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Note: This page contains sample records for the topic "multiphase reactive geochemical" from the National Library of EnergyBeta (NLEBeta).
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1

TOUGHREACT-A simulation program for non-isothermal multiphase reactive geochemical transport in variably saturated geologic media: Applications to geothermal injectivity and CO2 geological sequestration  

Science Conference Proceedings (OSTI)

TOUGHREACT is a numerical simulation program for chemically reactive non-isothermal flows of multiphase fluids in porous and fractured media. The program was written in Fortran 77 and developed by introducing reactive geochemistry into the multiphase ... Keywords: CO2 geologic sequestration, Clay swelling, Geochemical transport, Hydrothermal systems, Injectivity enhancement, Mineral scaling, Mineral trapping, Reactive fluid flow, Saline aquifer, TOUGHREACT

Tianfu Xu; Eric Sonnenthal; Nicolas Spycher; Karsten Pruess

2006-03-01T23:59:59.000Z

2

TOUGHREACT User's Guide: A Simulation Program for Non-isothermal Multiphase Reactive geochemical Transport in Variable Saturated Geologic Media  

DOE Green Energy (OSTI)

Coupled modeling of subsurface multiphase fluid and heat flow, solute transport and chemical reactions can be used for the assessment of mineral alteration in hydrothermal systems, waste disposal sites, acid mine drainage remediation, contaminant transport, and groundwater quality. A comprehensive non-isothermal multi-component reactive fluid flow and geochemical transport simulator, TOUGHREACT, has been developed. A wide range of subsurface thermo-physical-chemical processes is considered under various thermohydrological and geochemical conditions of pressure, temperature, water saturation, and ionic strength. The program can be applied to one-, two- or three-dimensional porous and fractured media with physical and chemical heterogeneity. The model can accommodate any number of chemical species present in liquid, gas and solid phases. A variety of equilibrium chemical reactions are considered, such as aqueous complexation, gas dissolution/exsolution, and cation exchange. Mineral dissolution/precipitation can proceed either subject to local equilibrium or kinetic conditions. Changes in porosity and permeability due to mineral dissolution and precipitation can be considered. Linear adsorption and decay can be included. For the purpose of future extensions, surface complexation by double layer model is coded in the program. Xu and Pruess (1998) developed a first version of a non-isothermal reactive geochemical transport model, TOUGHREACT, by introducing reactive geochemistry into the framework of the existing multi-phase fluid and heat flow code TOUGH2 (Pruess, 1991). Xu, Pruess, and their colleagues have applied the program to a variety of problems such as: (1) supergene copper enrichment (Xu et al, 2001), (2) caprock mineral alteration in a hydrothermal system (Xu and Pruess, 2001a), and (3) mineral trapping for CO{sub 2} disposal in deep saline aquifers (Xu et al, 2003b and 2004a). For modeling the coupled thermal, hydrological, and chemical processes during heater tests at proposed nuclear waste disposal site at Yucca Mountain (Nevada), Sonnenthal and Spycher (2000) and Spycher et al. (2003) enhanced TOUGHREACT on (1) high temperature geochemistry, (2) mineral reactive surface area calculations, and (3) porosity and permeability changes due to mineral alteration. On the other hand, Pruess et al. (1999) updated the TOUGH2 simulator to TOUGH2 V2. The present version of TOUGHREACT was developed by introducing the work of Sonnenthal and Spycher (2000) to the original work of Xu and Pruess (1998), and by replacing TOUGH2 (Pruess, 1991) by TOUGH2 V2 (Pruess et al, 1999). The TOUGHREACT program makes use of ''self-documenting'' features. It is distributed with a number of input data files for sample problems. Besides providing benchmarks for proper code installation, these can serve as self-teaching tutorial in the use of TOUGHREACT, and they provide templates to help jump-start new applications. The fluid and heat flow part of TOUGHREACT is derived from TOUGH2 V2, so in addition to the current manual, users must have manual of the TOUGH2 V2 (Pruess et al., 1999). The present version of TOUGHREACT provides the following different TOUGH2 fluid property or ''EOS'' (equation-of-state) modules: (1) EOS1 for water, or two waters with typical applications to hydrothermal problems, (2) EOS2 for multiphase mixtures of water and CO{sub 2} also with typical applications to hydrothermal problems, (3) EOS3 for multiphase mixtures of water and air with typical applications to vadose zone and nuclear waste disposal problems, (4) EOS4 that has the same capabilities as EOS3 but with vapor pressure lowering effects due to capillary pressure, (5) EOS9 for single phase water (Richards. equation) with typical applications to ambient reactive geochemical transport problems, (6) ECO2 for multiphase mixtures of water, CO{sub 2} and NaCl with typical applications to CO{sub 2} disposal in deep brine aquifers.

Xu, Tianfu; Sonnenthal, Eric; Spycher, Nicolas; Pruess, Karsten

2004-05-24T23:59:59.000Z

3

TOURGHREACT: A Simulation Program for Non-isothermal Multiphase Reactive Geochemical Transport in Variably Saturated Geologic Media  

E-Print Network (OSTI)

flows of multiphase fluids in porous and fractured media.multiphase fluid and heat flow. The program is applicable to porous

Xu, Tianfu; Sonnenthal, Eric; Spycher, Nicolas; Pruess, Karsten

2004-01-01T23:59:59.000Z

4

TOURGHREACT: A Simulation Program for Non-isothermal MultiphaseReactive Geochemical Transport in Variably Saturated GeologicMedia  

DOE Green Energy (OSTI)

TOUGHREACT is a numerical simulation program for chemically reactive non-isothermal flows of multiphase fluids in porous and fractured media. The program was written in Fortran 77 and developed by introducing reactive geochemistry into the multiphase fluid and heat flow simulator TOUGH2. A variety of subsurface thermo-physical-chemical processes are considered under a wide range of conditions of pressure, temperature, water saturation, ionic strength, and pH and Eh. Interactions between mineral assemblages and fluids can occur under local equilibrium or kinetic rates. The gas phase can be chemically active. Precipitation and dissolution reactions can change formation porosity and permeability. The program can be applied to many geologic systems and environmental problems, including geothermal systems, diagenetic and weathering processes, subsurface waste disposal, acid mine drainage remediation, contaminant transport, and groundwater quality. Here we present two examples to illustrate applicability of the program: (1) injectivity effects of mineral scaling in a fractured geothermal reservoir and (2) CO2 disposal in a deep saline aquifer.

Xu, Tianfu; Sonnenthal, Eric; Spycher, Nicolas; Pruess, Karsten

2004-12-07T23:59:59.000Z

5

TOUGHREACT: a new code of the TOUGH Family for Non-Isothermal multiphase reactive geochemical transport in variably saturated geologic media  

E-Print Network (OSTI)

multiphase flow, solute transport and reactive chemistry in porousmultiphase fluid flow, mass transport and chemical reactions, (2) we consider not only porous

Xu, Tianfu; Sonnenthal, Eric; Spycher, Nicolas; Pruess, Karsten

2003-01-01T23:59:59.000Z

6

TOURGHREACT: A Simulation Program for Non-isothermal Multiphase Reactive Geochemical Transport in Variably Saturated Geologic Media  

E-Print Network (OSTI)

for modeling fluid and heat flow in fractured porous media.flows of multiphase fluids in porous and fractured media.

Xu, Tianfu; Sonnenthal, Eric; Spycher, Nicolas; Pruess, Karsten

2004-01-01T23:59:59.000Z

7

TOUGHREACT User's Guide: A Simulation Program for Non-isothermal Multiphase Reactive Geochemical Transport in Variably Saturated Geologic Media, V1.2.1  

Science Conference Proceedings (OSTI)

Coupled modeling of subsurface multiphase fluid and heat flow, solute transport, and chemical reactions can be applied to many geologic systems and environmental problems, including geothermal systems, diagenetic and weathering processes, subsurface waste disposal, acid mine drainage remediation, contaminant transport, and groundwater quality. TOUGHREACT has been developed as a comprehensive non-isothermal multi-component reactive fluid flow and geochemical transport simulator to investigate these and other problems. A number of subsurface thermo-physical-chemical processes are considered under various thermohydrological and geochemical conditions of pressure, temperature, water saturation, and ionic strength. TOUGHREACT can be applied to one-, two- or three-dimensional porous and fractured media with physical and chemical heterogeneity. The code can accommodate any number of chemical species present in liquid, gas and solid phases. A variety of equilibrium chemical reactions are considered, such as aqueous complexation, gas dissolution/exsolution, and cation exchange. Mineral dissolution/precipitation can take place subject to either local equilibrium or kinetic controls, with coupling to changes in porosity and permeability and capillary pressure in unsaturated systems. Chemical components can also be treated by linear adsorption and radioactive decay. The first version of the non-isothermal reactive geochemical transport code TOUGHREACT was developed (Xu and Pruess, 1998) by introducing reactive geochemistry into the framework of the existing multi-phase fluid and heat flow code TOUGH2 (Pruess, 1991). TOUGHREACT was further enhanced with the addition of (1) treatment of mineral-water-gas reactive-transport under boiling conditions, (2) an improved HKF activity model for aqueous species, (3) gas species diffusion coefficients calculated as a function of pressure, temperature, and molecular properties, (4) mineral reactive surface area formulations for fractured and porous media, and (5) porosity, permeability, and capillary pressure changes owing to mineral precipitation/dissolution (Sonnenthal et al., 1998, 2000, 2001; Spycher et al., 2003a). Subsequently, TOUGH2 V2 was released with additional EOS modules and features (Pruess et al., 1999). The present version of TOUGHREACT includes all of the previous extensions to the original version, along with the replacement of the original TOUGH2 (Pruess, 1991) by TOUGH2 V2 (Pruess et al., 1999). TOUGHREACT has been applied to a wide variety of problems, some of which are included as examples, such as: (1) Supergene copper enrichment (Xu et al., 2001); (2) Mineral alteration in hydrothermal systems (Xu and Pruess, 2001a; Xu et al., 2004b; Dobson et al., 2004); (3) Mineral trapping for CO{sub 2} disposal in deep saline aquifers (Xu et al., 2003b and 2004a); (4) Coupled thermal, hydrological, and chemical processes in boiling unsaturated tuff for the proposed nuclear waste emplacement site at Yucca Mountain, Nevada (Sonnenthal et al., 1998, 2001; Sonnenthal and Spycher, 2000; Spycher et al., 2003a, b; Xu et al., 2001); (5) Modeling of mineral precipitation/dissolution in plug-flow and fracture-flow experiments under boiling conditions (Dobson et al., 2003); (6) Calcite precipitation in the vadose zone as a function of net infiltration (Xu et al., 2003); and (7) Stable isotope fractionation in unsaturated zone pore water and vapor (Singleton et al., 2004). The TOUGHREACT program makes use of 'self-documenting' features. It is distributed with a number of input data files for sample problems. Besides providing benchmarks for proper code installation, these can serve as a self-teaching tutorial in the use of TOUGHREACT, and they provide templates to help jump-start new applications. The fluid and heat flow part of TOUGHREACT is derived from TOUGH2 V2, so in addition to the current manual, users must have the manual of the TOUGH2 V2 (Pruess et al., 1999). The present version of TOUGHREACT provides the following TOUGH2 fluid property or 'EOS' (equation-of-state) modules: (1) EOS1 for

Xu, Tianfu; Sonnenthal, Eric; Spycher, Nicolas; Pruess, Karsten

2008-09-29T23:59:59.000Z

8

Multiphase fluid flow and subsequent geochemical transport in variably saturated fractured rocks: 1. Approaches  

E-Print Network (OSTI)

multiphase flow, solute transport and reactive chemistry in porousmultiphase flow, solute transport and reactive chemistry in porousmultiphase fluid flow, mass transport and chemical reactions, (2) we consider not only porous

Xu, Tianfu; Pruess, Karsten

2000-01-01T23:59:59.000Z

9

A comparison of results obtained with two subsurface non-isothermal multiphase reactive transport simulators, FADES-CORE and TOUGHREACT  

E-Print Network (OSTI)

saturated porous media with multiphase flow. FADES-CORE hasisothermal multiphase flow with reactive transport in porousmultiphase flow with multicomponent reactive transport in porous

Juncosa Rivera, Ricardo; Xu, Tianfu; Pruess, Karsten

2001-01-01T23:59:59.000Z

10

Coupled modeling of non-isothermal multiphase flow, solute transport and reactive chemistry in porous and fractured media: 1. Model Development and Validation  

E-Print Network (OSTI)

multiphase reactive transport, in Reactive transport in porousporous and fractured media under non-isothermal multiphaseporous and fractured media under non-isothermal multiphase

Xu, Tianfu; Pruess, Karsten

1998-01-01T23:59:59.000Z

11

TOUGHREACT Version 2.0: A simulator for subsurface reactive transport under non-isothermal multiphase flow conditions  

Science Conference Proceedings (OSTI)

TOUGHREACT is a numerical simulation program for chemically reactive non-isothermal flows of multiphase fluids in porous and fractured media, and was developed by introducing reactive chemistry into the multiphase fluid and heat flow simulator TOUGH2 ... Keywords: CO2 geological storage, Environmental remediation, Multi-phase flow, Nuclear waste geological disposal, Reactive transport, TOUGHREACT

Tianfu Xu; Nicolas Spycher; Eric Sonnenthal; Guoxiang Zhang; Liange Zheng; Karsten Pruess

2011-06-01T23:59:59.000Z

12

Using toughreact to model reactive fluid flow and geochemical transport in hydrothermal systems  

E-Print Network (OSTI)

multiphase flow, solute transport and reactive chemistry in porousmultiphase fluid flow, mass transport and chemical reactions, (2) reactive fluid flow and transport in fractured rocks as well as porous

Xu, Tianfu; Sonnenthal, Eric; Spycher, Nicolas; Pruess, Karsten

2003-01-01T23:59:59.000Z

13

Subsurface Transport Over Reactive Multiphases (STORM): A general, coupled, nonisothermal multiphase flow, reactive transport, and porous medium alteration simulator, Version 2 user's guide  

Science Conference Proceedings (OSTI)

The Hanford Site, in southeastern Washington State, has been used extensively to produce nuclear materials for the US strategic defense arsenal by the Department of Energy (DOE) and its predecessors, the US Atomic Energy Commission and the US Energy Research and Development Administration. A large inventory of radioactive and mixed waste has accumulated in 177 buried single- and double shell tanks. Liquid waste recovered from the tanks will be pretreated to separate the low-activity fraction from the high-level and transuranic wastes. Vitrification is the leading option for immobilization of these wastes, expected to produce approximately 550,000 metric tons of Low Activity Waste (LAW) glass. This total tonnage, based on nominal Na{sub 2}O oxide loading of 20% by weight, is destined for disposal in a near-surface facility. Before disposal of the immobilized waste can proceed, the DOE must approve a performance assessment, a document that described the impacts, if any, of the disposal facility on public health and environmental resources. Studies have shown that release rates of radionuclides from the glass waste form by reaction with water determine the impacts of the disposal action more than any other independent parameter. This report describes the latest accomplishments in the development of a computational tool, Subsurface Transport Over Reactive Multiphases (STORM), Version 2, a general, coupled non-isothermal multiphase flow and reactive transport simulator. The underlying mathematics in STORM describe the rate of change of the solute concentrations of pore water in a variably saturated, non-isothermal porous medium, and the alteration of waste forms, packaging materials, backfill, and host rocks.

DH Bacon; MD White; BP McGrail

2000-03-07T23:59:59.000Z

14

Modeling of concentrated aqueous solutions: Efficient implementation of Pitzer equations in geochemical and reactive transport models  

Science Conference Proceedings (OSTI)

Modeling concentrated solutions demands the use of ion-interaction models such as Pitzer equations, which involve a large number of operations. Implementation of these models in large reactive transport simulations significantly increases the computation ... Keywords: Concentrated solutions, Evaporation of seawater, Geochemical modeling, HMW model, Invariant points, Object-oriented programming, Pitzer, Reactive transport modeling

S. A. Bea; J. Carrera; C. Ayora; F. Batlle

2010-04-01T23:59:59.000Z

15

TOUGHREACT Version 2.0: A simulator for subsurface reactive transport under non-isothermal multiphase flow conditions  

E-Print Network (OSTI)

flows of multiphase fluids in porous and fractured media,flows of multiphase fluids in porous and fractured media (Xu

Xu, T.

2010-01-01T23:59:59.000Z

16

Microstructure evolution in TiN films reactively sputter deposited on multiphase substrates  

SciTech Connect

Cross-sectional transmission electron microscopy (X-TEM) has been used to investigate the microstructure of TiN films deposited by reactive magnetron sputtering onto ASP 30 high speed steel (HSS) substrates. ASP 30 is a multiphase material consisting of a martensitic matrix with MC and M/sub 6/C transition--metal particles embedded in it. The TiN films were approx.4 ..mu..m thick and were grown at substrate temperatures T/sub s/ between 200 and 550/sup 0/C. The X-TEM results showed that the film microstructure was very nonhomogeneous. A dense columnar morphology was observed above both the martensitic and M/sub 6/C substrate phases. The average column diameter ranged from 15 nm (T/sub s/ = 200/sup 0/C) to 50 nm (T/sub s/ = 550/sup 0/C) near the film/substrate interface over the martensitic phase and was in a factor of 2 less in the film regions adjacent to the M/sub 6/C phase. increased in both regions to 100 nm (T/sub s/ = 200/sup 0/C) to 150 nm (T/sub s/ = 550/sup 0/C) near the surface of the films. TiN grew epitaxially on MC particles but contained a high dislocation density which (except at 550/sup 0/C where some of the epitaxial grains extended throughout the entire film thickness) eventually coalesced to form low-angle grain boundaries and, finally, high-angle boundaries.

Helmersson, U.; Sundgren, J.; Greene, J.E.

1986-05-01T23:59:59.000Z

17

TOUGHREACT Version 2.0: A simulator for subsurface reactive transport under non-isothermal multiphase flow conditions  

DOE Green Energy (OSTI)

TOUGHREACT is a numerical simulation program for chemically reactive non-isothermal flows of multiphase fluids in porous and fractured media, and was developed by introducing reactive chemistry into the multiphase fluid and heat flow simulator TOUGH2 V2. The first version of TOUGHREACT was released to the public through the U.S. Department of Energy's Energy Science and Technology Software Center (ESTSC) in August 2004. It is among the most frequently requested of ESTSC's codes. The code has been widely used for studies in CO{sub 2} geological sequestration, nuclear waste isolation, geothermal energy development, environmental remediation, and increasingly for petroleum applications. Over the past several years, many new capabilities have been developed, which were incorporated into Version 2 of TOUGHREACT. Major additions and improvements in Version 2 are discussed here, and two application examples are presented: (1) long-term fate of injected CO{sub 2} in a storage reservoir and (2) biogeochemical cycling of metals in mining-impacted lake sediments.

Xu, T.; Spycher, N.; Sonnenthal, E.; Zhang, G.; Zheng, L.; Pruess, K.

2010-08-01T23:59:59.000Z

18

TOUGHREACT Version 2.0: A simulator for subsurface reactive transport under non-isothermal multiphase flow conditions  

E-Print Network (OSTI)

1985) for fluid and heat flow in fractured porous media. Theflows of multiphase fluids in porous and fractured media,flows of multiphase fluids in porous and fractured media (Xu

Xu, T.

2010-01-01T23:59:59.000Z

19

Corrosion-induced gas generation in a nuclear waste repository: Reactive geochemistry and multiphase flow effect  

DOE Green Energy (OSTI)

Corrosion of steel canisters, stored in a repository for spent fuel and high-level nuclear wastes, leads to the generation and accumulation of hydrogen gas in the backfilled emplacement tunnels, which may significantly affect long-term repository safety. Previous studies used H{sub 2} generation rates based on the volume of the waste or canister material and the stoichiometry of the corrosion reaction. However, iron corrosion and H{sub 2} generation rates vary with time, depending on factors such as amount of iron, water availability, water contact area, and aqueous and solid chemistry. To account for these factors and feedback mechanisms, we developed a chemistry model related to iron corrosion, coupled with two-phase (liquid and gas) flow phenomena that are driven by gas-pressure buildup associated with H{sub 2} generation and water consumption. Results indicate that by dynamically calculating H{sub 2} generation rates based on a simple model of corrosion chemistry, and by coupling this corrosion reaction with two-phase flow processes, the degree and extent of gas pressure buildup could be much smaller compared to a model that neglects the coupling between flow and reactive transport mechanisms. By considering the feedback of corrosion chemistry, the gas pressure increases initially at the canister, but later decreases and eventually returns to a stabilized pressure that is slightly higher than the background pressure. The current study focuses on corrosion under anaerobic conditions for which the coupled hydrogeochemical model was used to examine the role of selected physical parameters on the H{sub 2} gas generation and corresponding pressure buildup in a nuclear waste repository. The developed model can be applied to evaluate the effect of water and mineral chemistry of the buffer and host rock on the corrosion reaction for future site-specific studies.

Xu, T.; Senger, R.; Finsterle, S.

2008-10-15T23:59:59.000Z

20

TOUGHREACT User's Guide: A Simulation Program for Non-isothermal Multiphase Reactive geochemical Transport in Variable Saturated Geologic Media  

E-Print Network (OSTI)

for modeling fluid and heat flow in fractured porous media:1985) for fluid and heat flow in fractured porous media. The

Xu, Tianfu; Sonnenthal, Eric; Spycher, Nicolas; Pruess, Karsten

2004-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "multiphase reactive geochemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Modeling and Simulation of Pore Scale Multiphase Fluid Flow and Reactive Transport in Fractured and Porous Media  

Science Conference Proceedings (OSTI)

In the subsurface fluids play a critical role by transporting dissolved minerals, colloids and contaminants (sometimes over long distances), by mediating dissolution and precipitation processes and enabling chemical transformations in solution and at mineral surfaces. Although the complex geometries of fracture apertures, fracture networks and pore spaces may make it difficult to accurately predict fluid flow in saturated (single-phase) subsurface systems, well developed methods are available. The simulation of multiphase fluid flow in the subsurface is much more challenging because of the large density and/or viscosity ratios found in important applications (water/air in the vadose zone, water/oil, water/gas, gas/oil and water/oil/gas in oil reservoirs, water/air/non-aqueous phase liquids (NAPL) in contaminated vadose zone systems and gas/molten rock in volcanic systems, for example). In addition, the complex behavior of fluid-fluid-solid contact lines, and its impact on dynamic contact angles, must also be taken into account, and coupled with the fluid flow. Pore network models and simple statistical physics based models such as the invasion percolation and diffusion-limited aggregation models have been used quite extensively. However, these models for multiphase fluid flow are based on simplified models for pore space geometries and simplified physics. Other methods such a lattice Boltzmann and lattice gas models, molecular dynamics, Monte Carlo methods, and particle methods such as dissipative particle dynamics and smoothed particle hydrodynamics are based more firmly on first principles, and they do not require simplified pore and/or fracture geometries. However, they are less (in some cases very much less) computationally efficient that pore network and statistical physics models. Recently a combination of continuum computation fluid dynamics, fluid-fluid interface tracking or capturing and simple models for the dependence of contact angles on fluid velocity at the contact line has been used to simulate multiphase fluid flow in fracture apertures, fracture networks and pore spaces. Fundamental conservation principles - conservation of momentum, and conservation of mass (or conservation of volume for incompressible fluids) and conservation of energy, as well as symmetries (Galilean invariance and isotropy) are central to the physics of fluids and the models used to simulate them. In molecular and mesoscale models observance of these conservation principles and symmetries at the microscopic level leads to macroscopic fluid dynamics that can be represented by the Navier Stokes equation. The remarkable fact that the flow of all simpe fluids, irrespective of their chemical nature, can be described by the Navier-Stokes equation is a result of these conservation principles and symmetries acting on the molecular level.

Paul Meakin; Alexandre Tartakovsky

2009-07-01T23:59:59.000Z

22

Coupled modeling of non-isothermal multiphase flow, solutetransport and reactive chemistry in porous and fractured media: 1. ModelDevelopment and Validation  

Science Conference Proceedings (OSTI)

Coupled modeling of subsurface multiphase fluid and heat flow, solute transport and chemical reactions can be used for the assessment of acid mine drainage remediation, mineral deposition, waste disposal sites, hydrothermal convection, contaminant transport, and groundwater quality. Here they present a numerical simulation model, TOUGHREACT, which considers non-isothermal multi-component chemical transport in both liquid and gas phases. A wide range of subsurface thermo-physical-chemical processes is considered. The model can be applied to one-, two- or three-dimensional porous and fractured media with physical and chemical heterogeneity. The model can accommodate any number of chemical species present in liquid, gas and solid phases. A variety of equilibrium chemical reactions is considered, such as aqueous complexation, gas dissolution/exsolution, cation exchange, and surface complexation. Mineral dissolution/precipitation can proceed either subject to local equilibrium or kinetic conditions. The coupled model employs a sequential iteration approach with reasonable computing efficiency. The development of the governing equations and numerical approach is presented along with the discussion of the model implementation and capabilities. The model is verified for a wide range of subsurface physical and chemical processes. The model is well suited for flow and reactive transport in variably saturated porous and fractured media. In the second of this two-part paper, three applications covering a variety of problems are presented to illustrate the capabilities of the model.

Xu, Tianfu; Pruess, Karsten

1998-09-01T23:59:59.000Z

23

Multiphase Reactive Transport modeling of Stable Isotope Fractionation of Infiltrating Unsaturated Zone Pore Water and Vapor Using TOUGHREACT  

Science Conference Proceedings (OSTI)

Numerical simulations of transport and isotope fractionation provide a method to quantitatively interpret vadose zone pore water stable isotope depth profiles based on soil properties, climatic conditions, and infiltration. We incorporate the temperature-dependent equilibration of stable isotopic species between water and water vapor, and their differing diffusive transport properties into the thermodynamic database of the reactive transport code TOUGHREACT. These simulations are used to illustrate the evolution of stable isotope profiles in semiarid regions where recharge during wet seasons disturbs the drying profile traditionally associated with vadose zone pore waters. Alternating wet and dry seasons lead to annual fluctuations in moisture content, capillary pressure, and stable isotope compositions in the vadose zone. Periodic infiltration models capture the effects of seasonal increases in precipitation and predict stable isotope profiles that are distinct from those observed under drying (zero infiltration) conditions. After infiltration, evaporation causes a shift to higher 18O and D values, which are preserved in the deeper pore waters. The magnitude of the isotopic composition shift preserved in deep vadose zone pore waters varies inversely with the rate of infiltration.

Singleton, Michael J.; Sonnenthal, Eric L.; Conrad, Mark E.; DePaolo, Donald J.

2003-08-28T23:59:59.000Z

24

Multiphase Flow Modeling Research  

NLE Websites -- All DOE Office Websites (Extended Search)

Science Chris Guenther, Director Computational Science Division RUA Spring Meeting, Morgantown, WV March 2013 2 NETL's Multiphase Flow Science Team * The Multiphase Flow Science...

25

TOUGHREACT User's Guide: A Simulation Program for Non-isothermal Multiphase Reactive Geochemical Transport in Variably Saturated Geologic Media, V1.2.1  

E-Print Network (OSTI)

mineralogic model of Yucca Mountain, Nevada, Rev 2.0 . , Losfrom tuffs at Yucca Mountain, Nevada, USA. Geochim.in zeolitized tuffs at Yucca Mountain, Nevada, USA. Geochim.

Xu, Tianfu

2008-01-01T23:59:59.000Z

26

TOUGHREACT User's Guide: A Simulation Program for Non-isothermal Multiphase Reactive Geochemical Transport in Variably Saturated Geologic Media, V1.2.1  

E-Print Network (OSTI)

for modeling fluid and heat flow in fractured porous media:1985) for fluid and heat flow in fractured porous media. The

Xu, Tianfu

2008-01-01T23:59:59.000Z

27

TOUGHREACT User's Guide: A Simulation Program for Non-isothermal Multiphase Reactive Geochemical Transport in Variably Saturated Geologic Media, V1.2.1  

E-Print Network (OSTI)

Drift, heat was applied solely to the drift-center gridsquares) indicate grid block coordinates. Heat was appliedgrid block KCYC=KCYC+1 Time step: ?t Solve fluid and heat

Xu, Tianfu

2008-01-01T23:59:59.000Z

28

Multiphase flow calculation software  

DOE Patents (OSTI)

Multiphase flow calculation software and computer-readable media carrying computer executable instructions for calculating liquid and gas phase mass flow rates of high void fraction multiphase flows. The multiphase flow calculation software employs various given, or experimentally determined, parameters in conjunction with a plurality of pressure differentials of a multiphase flow, preferably supplied by a differential pressure flowmeter or the like, to determine liquid and gas phase mass flow rates of the high void fraction multiphase flows. Embodiments of the multiphase flow calculation software are suitable for use in a variety of applications, including real-time management and control of an object system.

Fincke, James R. (Idaho Falls, ID)

2003-04-15T23:59:59.000Z

29

Multiphase Flow Modeling Research  

NLE Websites -- All DOE Office Websites (Extended Search)

Science Science Chris Guenther, Director Computational Science Division RUA Spring Meeting, Morgantown, WV March 2013 2 NETL's Multiphase Flow Science Team * The Multiphase Flow Science Team develops physics-based simulation models to conduct applied scientific research. - Development of new theory - Extensive on-site and collaborative V&V efforts and testing - Engages in technology transfer - Applies the models to industrial scale problems. 3 Why is Multiphase Flow Science Needed? * Industry is increasingly relying on multiphase technologies to produce clean and affordable energy with carbon capture. * Unfortunately, the presence of a solid phase reduces the operating capacity of a typical energy device from its original design on average by 40% [1].

30

Multiphase Stirling Engines  

E-Print Network (OSTI)

Analysis, design, fabrication, and experimental assessment of a symmetric three-phase free-piston Stirling engine system is discussed in this paper. The system is designed to operate with moderate-temperature heat input that is consistent with solar-thermal collectors. Diaphragm pistons and nylon flexures are considered for this prototype to eliminate surface friction and to provide appropriate seals. In addition, low loss diaphragm pistons, etched and woven-wire screen heat exchangers, and plastic flexures, as the main components of the system, are outlined. The experimental results are presented and compared with design analysis. Experiments successfully confirm the design models for heat exchanger flow friction losses and gas spring hysteresis dissipation. Furthermore, it is revealed that gas spring hysteresis loss is an important dissipation phenomenon for low-power Stirling engines and should be carefully addressed in design. Analysis shows that the gas hysteresis dissipation is reduced drastically by increasing the number of phases in a multiphase Stirling engine system. It is further shown that for an even number of phases, half of the engine chambers could be eliminated by utilizing a reversing mechanism within the multiphase system. The mathematical formulation and modal analysis of multiphase Stirling engine system are then extended to a system that incorporates a reverser. By introducing a reverser to the fabricated prototype, the system successfully operates in engine mode. The system proves its self-starting capability and validates the computed start-up temperature. ?DOI: 10.1115/1.3097274? 1

Artin Der Minassians; Seth R. Sanders

2009-01-01T23:59:59.000Z

31

'Multi-Phase' Steel Microstructures  

Science Conference Proceedings (OSTI)

Application of Conical Beam X-Ray Tomography to Multi-Phase Materials ... Digital Construction and Characterization of Reticulated Porous Microstructures ...

32

Mercury Geochemical, Groundwater Geochemical, And Radiometric Geophysical  

Open Energy Info (EERE)

Geochemical, Groundwater Geochemical, And Radiometric Geophysical Geochemical, Groundwater Geochemical, And Radiometric Geophysical Signatures At Three Geothermal Prospects In Northern Nevada Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Paper: Mercury Geochemical, Groundwater Geochemical, And Radiometric Geophysical Signatures At Three Geothermal Prospects In Northern Nevada Details Activities (14) Areas (3) Regions (0) Abstract: Ground water sampling, desorbed mercury soil geochemical surveys and a radiometric geophysical survey was conducted in conjunction with geological mapping at three geothermal prospects in northern Nevada. Orientation sample lines from 610 m (2000 ft.) to 4575 m (15,000 ft.) in length were surveyed at right angles to known and suspected faults. Scintillometer readings (gamma radiation - total counts / second) were also

33

Developing a robust geochemical and reactive transport model to evaluate possible sources of arsenic at the CO2 sequestration natural analog site in Chimayo, New Mexico  

SciTech Connect

Migration of carbon dioxide (CO2) from deep storage formations into shallow drinking water aquifers is a possible system failure related to geologic CO2 sequestration. A CO2 leak may cause mineral precipitation/ dissolution reactions, changes in aqueous speciation, and alteration of pH and redox conditions leading to potential increases of trace metal concentrations above EPA National Primary Drinking Water Standards. In this study, the Chimayo site (NM) was examined for site-specific impacts of shallow groundwater interacting with CO2 from deep storage formations. Major ion and trace element chemistry for the site have been previously studied. This work focuses on arsenic (As), which is regulated by the EPA under the Safe Drinking Water Act and for which some wells in the Chimayo area have concentrations higher than the maximum contaminant level (MCL). Statistical analysis of the existing Chimayo groundwater data indicates that As is strongly correlated with trace metals U and Pb indicating that their source may be from the same deep subsurface water. Batch experiments and materials characterization, such as: X-ray diffraction (XRD), scanning electron microscopy (SEM), and synchrotron micro X-ray fluorescence (#2;-XRF), were used to identify As association with Fe-rich phases, such as clays or oxides, in the Chimayo sediments as the major factor controlling As fate in the subsurface. Batch laboratory experiments with Chimayo sediments and groundwater show that pH decreases as CO2 is introduced into the system and buffered by calcite. The introduction of CO2 causes an immediate increase in As solution concentration, which then decreases over time. A geochemical model was developed to simulate these batch experiments and successfully predicted the pH drop once CO2 was introduced into the experiment. In the model, sorption of As to illite, kaolinite and smectite through surface complexation proved to be the key reactions in simulating the drop in As concentration as a function of time in the batch experiments. Based on modeling, kaolinite precipitation is anticipated to occur during the experiment, which allows for additional sorption sites to form with time resulting in the slow decrease in As concentration. This mechanism can be viewed as trace metal “scavenging” due to sorption caused secondary mineral precipitation. Since deep geologic transport of these trace metals to the shallow subsurface by brine or CO2 intrusion is critical to assessing environmental impacts, the effective retardation of trace metal transport is an important parameter to estimate and it is dependent on multiple coupled reactions. At the field scale, As mobility is retarded due to the influence of sorption reactions, which can affect environmental performance assessment studies of a sequestration site.

Viswanathana, Hari; Daia, Zhenxue; Lopano, Christina; Keating, Elizabeth; Hakala, J. Alexandra; Scheckelc, Kirk G; Zhengd, Liange; Guthrie, George D.; Pawara, Rajesh

2012-01-01T23:59:59.000Z

34

Developing a robust geochemical and reactive transport model to evaluate possible sources of arsenic at the CO[subscript 2] sequestration natural analog site in Chimayo, New Mexico  

Science Conference Proceedings (OSTI)

Migration of carbon dioxide (CO{sub 2}) from deep storage formations into shallow drinking water aquifers is a possible system failure related to geologic CO{sub 2} sequestration. A CO{sub 2} leak may cause mineral precipitation/dissolution reactions, changes in aqueous speciation, and alteration of pH and redox conditions leading to potential increases of trace metal concentrations above EPA National Primary Drinking Water Standards. In this study, the Chimayo site (NM) was examined for site-specific impacts of shallow groundwater interacting with CO{sub 2} from deep storage formations. Major ion and trace element chemistry for the site have been previously studied. This work focuses on arsenic (As), which is regulated by the EPA under the Safe Drinking Water Act and for which some wells in the Chimayo area have concentrations higher than the maximum contaminant level (MCL). Statistical analysis of the existing Chimayo groundwater data indicates that As is strongly correlated with trace metals U and Pb indicating that their source may be from the same deep subsurface water. Batch experiments and materials characterization, such as: X-ray diffraction (XRD), scanning electron microscopy (SEM), and synchrotron micro X-ray fluorescence ({mu}-XRF), were used to identify As association with Fe-rich phases, such as clays or oxides, in the Chimayo sediments as the major factor controlling As fate in the subsurface. Batch laboratory experiments with Chimayo sediments and groundwater show that pH decreases as CO{sub 2} is introduced into the system and buffered by calcite. The introduction of CO{sub 2} causes an immediate increase in As solution concentration, which then decreases over time. A geochemical model was developed to simulate these batch experiments and successfully predicted the pH drop once CO{sub 2} was introduced into the experiment. In the model, sorption of As to illite, kaolinite and smectite through surface complexation proved to be the key reactions in simulating the drop in As concentration as a function of time in the batch experiments. Based on modeling, kaolinite precipitation is anticipated to occur during the experiment, which allows for additional sorption sites to form with time resulting in the slow decrease in As concentration. This mechanism can be viewed as trace metal 'scavenging' due to sorption caused secondary mineral precipitation. Since deep geologic transport of these trace metals to the shallow subsurface by brine or CO{sub 2} intrusion is critical to assessing environmental impacts, the effective retardation of trace metal transport is an important parameter to estimate and it is dependent on multiple coupled reactions. At the field scale, As mobility is retarded due to the influence of sorption reactions, which can affect environmental performance assessment studies of a sequestration site.

Viswanathan, Hari; Dai, Zhenxue; Lopano, Christina; Keating, Elizabeth; Hakala, J. Alexandra; Scheckel, Kirk G.; Zheng, Liange; Gutherie, George D.; Pawar, Rajesh (EPA); (LBNL); (LANL); (NETL)

2012-10-24T23:59:59.000Z

35

Numerical analyses of effective dielectric constant of multiphase microporous media  

E-Print Network (OSTI)

dielectric constant of multiphase porous media are bettermicrostructures of multiphase porous media, and a latticemicrostructures of multiphase porous media and a lattice

Wang, Moran; Pan, Ning

2007-01-01T23:59:59.000Z

36

Thermodynamic Data for Geochemical Modeling of Carbonate Reactions Associated with CO2 Sequestration – Literature Review  

Science Conference Proceedings (OSTI)

Permanent storage of anthropogenic CO2 in deep geologic formations is being considered as a means to reduce the concentration of atmospheric CO2 and thus its contribution to global climate change. To ensure safe and effective geologic sequestration, numerous studies have been completed of the extent to which the CO2 migrates within geologic formations and what physical and geochemical changes occur in these formations when CO2 is injected. Sophisticated, computerized reservoir simulations are used as part of field site and laboratory CO2 sequestration studies. These simulations use coupled multiphase flow-reactive chemical transport models and/or standalone (i.e., no coupled fluid transport) geochemical models to calculate gas solubility, aqueous complexation, reduction/oxidation (redox), and/or mineral solubility reactions related to CO2 injection and sequestration. Thermodynamic data are critical inputs to modeling geochemical processes. The adequacy of thermodynamic data for carbonate compounds has been identified as an important data requirement for the successful application of these geochemical reaction models to CO2 sequestration. A review of thermodynamic data for CO2 gas and carbonate aqueous species and minerals present in published data compilations and databases used in geochemical reaction models was therefore completed. Published studies that describe mineralogical analyses from CO2 sequestration field and natural analogue sites and laboratory studies were also reviewed to identify specific carbonate minerals that are important to CO2 sequestration reactions and therefore require thermodynamic data. The results of the literature review indicated that an extensive thermodynamic database exists for CO2 and CH4 gases, carbonate aqueous species, and carbonate minerals. Values of ?fG298° and/or log Kr,298° are available for essentially all of these compounds. However, log Kr,T° or heat capacity values at temperatures above 298 K exist for less than approximately one-third of these compounds. Because the temperatures of host formations that will be used for CO2 injection and sequestration will be at tempera¬tures in the range of 50şC to 100şC or greater, the lack of high temperature thermodynamic values for key carbonate compounds especially minerals, will impact the accuracy of some modeling calculations.

Krupka, Kenneth M.; Cantrell, Kirk J.; McGrail, B. Peter

2010-09-28T23:59:59.000Z

37

Optimization of the Refrigerant Capacity in Multiphase ...  

Science Conference Proceedings (OSTI)

Symposium, Magnetic Materials for Energy Applications. Presentation Title, Optimization of the Refrigerant Capacity in Multiphase Magnetocaloric Materials.

38

History of Geochemical Modeling  

Science Conference Proceedings (OSTI)

Table 1   Sources of geochemical modeling software...www.telusplanet.net/public/geogams/index SOLVEQ/CHILLER Mark H. Reed Department of Geological

39

MSTS - Multiphase Subsurface Transport Simulator theory manual  

SciTech Connect

The US Department of Energy, through the Yucca Mountain Site Characterization Project Office, has designated the Yucca Mountain site in Nevada for detailed study as the candidate US geologic repository for spent nuclear fuel and high-level radioactive waste. Site characterization will determine the suitability of the Yucca Mountain site for the potential waste repository. If the site is determined suitable, subsequent studies and characterization will be conducted to obtain authorization from the Nuclear Regulatory Commission to construct the potential waste repository. A principal component of the characterization and licensing processes involves numerically predicting the thermal and hydrologic response of the subsurface environment of the Yucca Mountain site to the potential repository over a 10,000-year period. The thermal and hydrologic response of the subsurface environment to the repository is anticipated to include complex processes of countercurrent vapor and liquid migration, multiple-phase heat transfer, multiple-phase transport, and geochemical reactions. Numerical simulators based on mathematical descriptions of these subsurface phenomena are required to make numerical predictions of the thermal and hydrologic response of the Yucca Mountain subsurface environment The engineering simulator called the Multiphase Subsurface Transport Simulator (MSTS) was developed at the request of the Yucca Mountain Site Characterization Project Office to produce numerical predictions of subsurface flow and transport phenomena at the potential Yucca Mountain site. This document delineates the design architecture and describes the specific computational algorithms that compose MSTS. Details for using MSTS and sample problems are given in the {open_quotes}User`s Guide and Reference{close_quotes} companion document.

White, M.D.; Nichols, W.E.

1993-05-01T23:59:59.000Z

40

Flow assurance and multiphase pumping  

E-Print Network (OSTI)

A robust understanding and planning of production enhancement and flow assurance is required as petroleum E&P activities are targeting deepwaters and long distances. Different flow assurance issues and their solutions are put together in this work. The use of multiphase pumps as a flow assurance solution is emphasized. Multiphase pumping aids flow assurance in different ways. However, the problem causing most concern is sand erosion. This work involved a detection-based sand monitoring method. Our objectives are to investigate the reliability of an acoustic sand detector and analyze the feasibility of gel injection as a method to mitigate sand erosion. Use of a sand detector coupled with twin-screw pumps is studied under varying flow conditions. The feasibility of gel injection to reduce slip and transport produced solids through twin-screw pump is investigated. A unique full-scale laboratory with multiphase pumps was utilized to carry out the experimental tests. The test results indicate that acoustic sand detection works in a narrow window around the calibration signature. An empirical correlation for predicting the twin-screw pump performance with viscous fluids was developed. It shows good agreement in the practical operational limits – 50% to 100% speed. The results indicate that viscous gel injection should be an effective erosion mitigation approach as it reduces slip, the principle cause of erosive wear. To correlate the performance of viscous fluid injection to hydroabrasive wear, further experimental investigation is needed.

Nikhar, Hemant G.

2006-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "multiphase reactive geochemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Modeling Macrosegregation with a Multiphase Approach  

Science Conference Proceedings (OSTI)

A multiphase approach is used to study the macrosegregation phenomena that ... caused by pore or gas bubble formation, deformation of the solid framework, ...

42

Geochemical Techniques | Open Energy Information  

Open Energy Info (EERE)

Geochemical Techniques Geochemical Techniques Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Geochemical Techniques Details Activities (0) Areas (0) Regions (0) NEPA(1) Exploration Technique Information Exploration Group: Geochemical Techniques Exploration Sub Group: None Parent Exploration Technique: Exploration Techniques Information Provided by Technique Lithology: Stratigraphic/Structural: Hydrological: Thermal: Dictionary.png Geochemical Techniques: No definition has been provided for this term. Add a Definition Related Techniques Geochemical Techniques Geochemical Data Analysis Geothermometry Gas Geothermometry Isotope Geothermometry Liquid Geothermometry Cation Geothermometers Multicomponent Geothermometers Silica Geothermometers Thermal Ion Dispersion

43

Modules based on the geochemical model PHREEQC for use in scripting and programming languages  

Science Conference Proceedings (OSTI)

The geochemical model PHREEQC is capable of simulating a wide range of equilibrium reactions between water and minerals, ion exchangers, surface complexes, solid solutions, and gases. It also has a general kinetic formulation that allows modeling of ... Keywords: C, C++, COM, Component object model, Fortran, Geochemical modeling, PHREEQC, Reactive-transport modeling

Scott R. Charlton; David L. Parkhurst

2011-10-01T23:59:59.000Z

44

Multiphase Flow Analysis in Hydra-TH  

SciTech Connect

This talk presents an overview of the multiphase flow efforts with Hydra-TH. The presentation begins with a definition of the requirements and design principles for multiphase flow relevant to CASL-centric problems. A brief survey of existing codes and their solution algorithms is presented before turning the model formulation selected for Hydra-TH. The issues of hyperbolicity and wellposedness are outlined, and a three candidate solution algorithms are discussed. The development status of Hydra-TH for multiphase flow is then presented with a brief summary and discussion of future directions for this work.

Christon, Mark A. [Los Alamos National Laboratory; Bakosi, Jozsef [Los Alamos National Laboratory; Francois, Marianne M. [Los Alamos National Laboratory; Lowrie, Robert B. [Los Alamos National Laboratory; Nourgaliev, Robert [Idaho National Laboratory

2012-06-20T23:59:59.000Z

45

A Physically Based Approach for Modeling Multiphase Fracture-Matrix Interaction in Fractured Porous Media  

E-Print Network (OSTI)

in modeling multiphase flow in porous and fractured media,multiphase tracer transport in heterogeneous fractured porousof multiphase flow through fractured or porous media.

Wu, Yu-Shu; Pan, Lehua; Pruess, Karsten

2004-01-01T23:59:59.000Z

46

Efficient Schemes for Reducing Numerical Dispersion in Modeling Multiphase Transport through Porous and Fractured Media  

E-Print Network (OSTI)

within a fluid in a multiphase- porous-medium system isand radiation in a multiphase, multicomponent, porous mediumModeling Multiphase Transport through Porous and Fractured

Wu, Yu-Shu; Forsyth, Peter A.

2006-01-01T23:59:59.000Z

47

GEOCHEMICAL CONTROLS ON NUCLEAR MAGNETIC RESONANCE MEASUREMENTS  

Science Conference Proceedings (OSTI)

Proton nuclear magnetic resonance (NMR) is used in the Earth Sciences as a means of obtaining information about the molecular-scale environment of fluids in porous geological materials. Laboratory experiments were conducted to advance our fundamental understanding of the link between the NMR response and the geochemical properties of geological materials. In the first part of this research project, we studied the impact of both the surface-area-to-volume ratio (S/V) of the pore space and the surface relaxivity on the NMR response of fluids in sand-clay mixtures. This study highlighted the way in which these two parameters control our ability to use NMR measurements to detect and quantify fluid saturation in multiphase saturated systems. The second part of the project was designed to explore the way in which the mineralogic form of iron, as opposed to simply the concentration of iron, affects the surface relaxation rate and, more generally, the NMR response of porous materials. We found that the magnitude of the surface relaxation rate was different for the various iron-oxide minerals because of changes in both the surface-area-to-volume ratio of the pore space, and the surface relaxivity. Of particular significance from this study was the finding of an anomalously large surface relaxivity of magnetite compared to that of the other iron minerals. Differences in the NMR response of iron minerals were seen in column experiments during the reaction of ferrihydrite-coated quartz sand with aqueous Fe(II) solutions to form goethite, lepidocrocite and magnetite; indicating the potential use of NMR as a means of monitoring geochemical reactions. The final part of the research project investigated the impact of heterogeneity, at the pore-scale, on the NMR response. This work highlighted the way in which the geochemistry, by controlling the surface relaxivity, has a significant impact on the link between NMR data and the microgeometry of the pore space.

Rosemary Knight

2008-08-25T23:59:59.000Z

48

Upscaling Reaction Rate Laws In Geochemical Reactive Transport Using Pore-Scale Network Models Dmitri Kavetski1,2,#, Catherine A. Peters1,$, Michael A. Celia1 and Brent Lindquist3  

E-Print Network (OSTI)

, Rutile, Pyrite GY BR Q Pore space Chemical Reactions and Kinetic Rate Laws Primary interest: acid geosequestration studies *aquifer remediation *nuclear waste disposal *other applications Reactive processes occur and examines whether reaction rates applicable at the pore-scale, O(10-100m), are realistic at larger continuum

Peters, Catherine A.

49

The TOUGH codes - a family of simulation tools for multiphase flow and transport processes in permeable media  

E-Print Network (OSTI)

Multiphase Tracer Transport in Heterogeneous Fractured PorousMultiphase Flow and Multicomponent Transport in Porous and

Pruess, Karsten

2003-01-01T23:59:59.000Z

50

Geochemical Data Analysis | Open Energy Information  

Open Energy Info (EERE)

Geochemical Data Analysis Geochemical Data Analysis Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Geochemical Data Analysis Details Activities (0) Areas (0) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Geochemical Techniques Exploration Sub Group: Geochemical Data Analysis Parent Exploration Technique: Geochemical Techniques Information Provided by Technique Lithology: Stratigraphic/Structural: Hydrological: Thermal: Dictionary.png Geochemical Data Analysis: No definition has been provided for this term. Add a Definition References No exploration activities found. Print PDF Retrieved from "http://en.openei.org/w/index.php?title=Geochemical_Data_Analysis&oldid=594157" Categories: Geochemical Techniques Exploration Techniques

51

Nanostructured Multi-Phase Titanium Based Materials Consolidated ...  

Science Conference Proceedings (OSTI)

Abstract Scope, Nanostructured multi-phase titanium based materials were produced by severe ... Electrolytic Infiltration of Laser Sintered Porous Preforms.

52

Benchmarking a Visual-Basic based multi-component one-dimensional reactive transport modeling tool  

Science Conference Proceedings (OSTI)

We present the details of a comprehensive numerical modeling tool, RT1D, which can be used for simulating biochemical and geochemical reactive transport problems. The code can be run within the standard Microsoft EXCEL Visual Basic platform, and it does ... Keywords: Bioremediation, Geochemical transport, Groundwater models, Numerical model, Reactive transport

Jagadish Torlapati; T. Prabhakar Clement

2013-01-01T23:59:59.000Z

53

Multiphase fluid flow and subsequent geochemical transport in variably saturated fractured rocks: 1. Approaches  

E-Print Network (OSTI)

dissolution and precipitation. Here we present a comprehensive modeling approach and numerical methods

Xu, Tianfu; Pruess, Karsten

2000-01-01T23:59:59.000Z

54

Numerical simulation of single-phase and multiphase non-Darcy flow in porous and fractured reservoirs  

E-Print Network (OSTI)

well tests, multiphase flow, porous and fracturedin modeling multiphase flow in porous and fractured media,”description of multiphase flow through porous media: S w + S

Wu, Yu-Shu

2000-01-01T23:59:59.000Z

55

PFLOTRAN: Reactive Flow & Transport Code for Use on Laptops to Leadership-Class Supercomputers  

SciTech Connect

PFLOTRAN, a next-generation reactive flow and transport code for modeling subsurface processes, has been designed from the ground up to run efficiently on machines ranging from leadership-class supercomputers to laptops. Based on an object-oriented design, the code is easily extensible to incorporate additional processes. It can interface seamlessly with Fortran 9X, C and C++ codes. Domain decomposition parallelism is employed, with the PETSc parallel framework used to manage parallel solvers, data structures and communication. Features of the code include a modular input file, implementation of high-performance I/O using parallel HDF5, ability to perform multiple realization simulations with multiple processors per realization in a seamless manner, and multiple modes for multiphase flow and multicomponent geochemical transport. Chemical reactions currently implemented in the code include homogeneous aqueous complexing reactions and heterogeneous mineral precipitation/dissolution, ion exchange, surface complexation and a multirate kinetic sorption model. PFLOTRAN has demonstrated petascale performance using 2{sup 17} processor cores with over 2 billion degrees of freedom. Accomplishments achieved to date include applications to the Hanford 300 Area and modeling CO{sub 2} sequestration in deep geologic formations.

Hammond, Glenn E.; Lichtner, Peter C.; Lu, Chuan; Mills, Richard T.

2012-04-18T23:59:59.000Z

56

Modeling multiphase flow in porous medium systems at multiple scales.  

E-Print Network (OSTI)

??Problems involving multiphase flow and transport in porous media arise in a number of scientific and engineering applications including oil reservoir engineering and groundwater remediation.… (more)

Li, Huina.

2006-01-01T23:59:59.000Z

57

Isothermal Multiphase Fluid Flow and Capillary Instabilities in ...  

Science Conference Proceedings (OSTI)

... on the buoyant migration of a gas phase invading a saturated porous anode. ... and numerical computing that solve the multiphase dynamics at pore scale.

58

Discontinuous Galerkin formulation for multi-component multiphase flow.  

E-Print Network (OSTI)

??The understanding of multiphase multi-component transport in capillary porous media plays an important role in scientific and engineering disciplines such as the petroleum and environmental… (more)

Ho, Christina

2010-01-01T23:59:59.000Z

59

Multiphase Flow in a Steelmaking Converter Using an ...  

Science Conference Proceedings (OSTI)

Abstract Scope, The influence of an unconventional lance on the multiphase fluid ... However, the performance of the unconventional lance strongly depends on ...

60

Approval for Use of the Minnesota Multiphasic Personality Inventory...  

NLE Websites -- All DOE Office Websites (Extended Search)

OF HEAL TH, SAFETY AND SECURITY Approval for Use of Minnesota Multiphasic Personality Inventory-2 Revised Format and Psychological Assessment Inventory Under title IO, Code of...

Note: This page contains sample records for the topic "multiphase reactive geochemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Lessons learned from reactive transport modeling of a low-activity waste glass disposal system  

Science Conference Proceedings (OSTI)

A set of reactive chemical transport calculations were conducted with the Subsurface Transport Over Reactive Multiphases (STORM) code to evaluate the long-term performance of a representative low-activity waste glass in a shallow subsurface disposal ... Keywords: chemical transport, low-level waste, numerical model, unsaturated flow, vadose zone

Diana H. Bacon; B. Peter McGrail

2003-04-01T23:59:59.000Z

62

Category:Geochemical Techniques | Open Energy Information  

Open Energy Info (EERE)

source source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Category Edit History Facebook icon Twitter icon » Category:Geochemical Techniques Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Geothermalpower.jpg Looking for the Geochemical Techniques page? For detailed information on exploration techniques, click here. Category:Geochemical Techniques Add.png Add a new Geochemical Techniques Technique Subcategories This category has only the following subcategory. G [×] Geochemical Data Analysis‎ 3 pages Pages in category "Geochemical Techniques" This category contains only the following page. G Geochemical Data Analysis Retrieved from "http://en.openei.org/w/index.php?title=Category:Geochemical_Techniques&oldid=689823"

63

Injection and Reservoir Hazard Management: The Role of Injection-Induced Mechanical Deformation and Geochemical Alteration at In Salah CO2 Storage Project: Status ReportQuarter end, June 2009  

Science Conference Proceedings (OSTI)

The In Salah Gas Project (ISG), a joint venture (JV) of BP, Sonatrach, and StatoilHydro, has two fundamental goals: (1) 25-30 years of 9 bcfy natural gas production from 8 fields in the Algerian Central Sahara, and (2) successful minimization of the associated environmental footprint by capture and subsurface isolation of the excess CO{sub 2} extracted from production streams and subsurface isolation in the Krechba sandstone reservoir. The In Salah project provides an opportunity to study key physical and chemical processes in operational deployment of geological carbon sequestration. The objectives of the research are to study two components relevant to storage effectiveness and operational success at In Salah: Reactive chemistry of the brine-CO{sub 2}-reservoir-caprock-wellbore system, and the geomechanical effects of large-scale injection on crustal deformation and fault leakage hazards. Results from this work will enhance predictive capability of field performance, provide a new basis for interpretation of geophysical monitoring at In Salah, and provide additional information relevant to the creation of geological sequestration standards. The Joint Industry Partners (JIP: BP, StatoilHydro, Sonatrach) and LLNL will share data and results to achieve the objectives of the proposed work. The objective of the work performed at LLNL is to integrate LLNL core strengths in geochemistry and geomechanics to better understand and predict the fate of injected CO{sub 2} in the field. The mechanical, chemical and transport properties of the reservoir-caprock system are coupled. We are using LLNL-developed quantitative tools to assess the potential for CO{sub 2} migration/leakage caused by injection-induced deformation. The geomechanical work is focused upon fault activation, fluid induced fracturing of the caprock and permeability field evolution of the fractured reservoir. These results will be used in concert with reactive transport calculations to predict the ultimate fate of the CO{sub 2}. We will integrate laboratory and reactive transport modeling to assess CO{sub 2} plume migration and partitioning between different trapping mechanisms. Geochemical reactive transport modeling will be used to address multiphase flow (supercritical CO{sub 2} and water), CO{sub 2} dissolution, mineral sequestration, and porosity/permeability changes. The reactive transport portion of the work ultimately couples with geomechanical modeling. In particular, the distribution of the pressure perturbation induced by injection drives the geomechanical response. Subsequently, the geochemical work determines if water-rock interactions eventually enhance or suppress fractures. A key focus of this work is to establish the site specific interactions of geomechanics, reactive flow and transport. This involves building and refining models of the reservoir and overburden. The models will undergo continual refinement in response to data collected in the field and experiments performed at LLNL and elsewhere. This project commenced in FY08, with DOE funding starting in April, FY08. We have successfully initiated a cross-disciplinary study of the In Salah CO{sub 2} sequestration project and have met all FY08 and FY09 Q1, Q2 and Q3 milestones. During the reporting period, we continued to acquire and process data from the JIP to import into our own geomechanical and geochemical computational tools. The lab testing program continued using both locally formulated cements and field samples from Krechba. The geomechanical studies indicate that pore fluid pressures induced by injection will lead to significant permeability enhancement of the combination of fracture network and fault network within the reservoir in the vicinity of the injectors. We continued reactive transport calculations for CO{sub 2} rich fluids flowing through fractures. These calculations demonstrate that although porosity and permeability changes are expected in response to CO{sub 2} injection they are not anticipated to have a significant effect upon transport properties within the reservoir or c

Morris, J P; McNab, W W; Carroll, S K; Hao, Y; Foxall, W; Wagoner, J L

2009-07-30T23:59:59.000Z

64

Shock Scattering in Multiphase Flow Model  

Science Conference Proceedings (OSTI)

Multiphase flow models have been proposed for use in situations which have combined Rayleigh-Taylor (RTI) and Richtmyer-Meshkov (RMI) instabilities. Such an approach works poorly for the case of a heavy to light shock incidence on a developed interface. The physical original of this difficulty is traced to an inadequate model of the interfacial pressure term as it appears in the momentum and turbulence kinetic energy equations. Constraints on the form of a better model from a variety of sources are considered. In this context it is observed that a new constraint on closures arises. This occurs because of the discontinuity within the shock responsible for the RMI. The proposed model (Shock Scattering) is shown to give useful results.

Klem, D

2003-10-16T23:59:59.000Z

65

Shock Scattering in a Multiphase Flow Model  

Science Conference Proceedings (OSTI)

Multiphase flow models have been proposed for use in situations which have combined Rayleigh-Taylor (RTI) and Richtmyer-Meshkov (RMI) instabilities. Such an approach work poorly for the case of a heavy to light shock incidence on a developed interface. The physical original of this difficulty is traced to an inadequate model of the interfacial pressure term as it appears in the momentum and turbulence kinetic energy equations. Constraints on the form of a better model from a variety of sources are considered. In this context it is observed that a new constraint on closures arises. This occurs because of the discontinuity within the shock responsible for the RMI. The proposed model (Shock Scattering) is shown to give useful results.

Klem, D

2003-04-08T23:59:59.000Z

66

Gasificaton Transport: A Multiphase CFD Approach & Measurements  

DOE Green Energy (OSTI)

The objective of this project was to develop predictive theories for the dispersion and mass transfer coefficients and to measure them in the turbulent fluidization regime, using existing facilities. A second objective was to use our multiphase CFD tools to suggest optimized gasifier designs consistent with aims of Future Gen. We have shown that the kinetic theory based CFD codes correctly compute: (1) Dispersion coefficients; and (2) Mass transfer coefficients. Hence, the kinetic theory based CFD codes can be used for fluidized bed reactor design without any such inputs. We have also suggested a new energy efficient method of gasifying coal and producing electricity using a molten carbonate fuel cell. The principal product of this new scheme is carbon dioxide which can be converted into useful products such as marble, as is done very slowly in nature. We believe this scheme is a lot better than the canceled FutureGen, since the carbon dioxide is safely sequestered.

Dimitri Gidaspow; Veeraya Jiradilok; Mayank Kashyap; Benjapon Chalermsinsuwan

2009-02-14T23:59:59.000Z

67

Multiphase flow analysis of oil shale retorting  

DOE Green Energy (OSTI)

Several multiphase phenomena occur during oil shale retorting. An analysis is presented of two of these processes including condensation of oil shale vapor and oscillations of pressure in oil shale blocks through cracked bedding planes. Energy conservation equations for oil shale retorting, which include the effects associated with condensation of oil, are derived on the basis of two phase flow theory. It is suggested that an effective heat capacity associated with the latent heat of condensation should be included in the modeling of simulated modified in-situ oil shale retorting. A pressure propagation equation for fast transients in oil shale cracks has been derived and examined in view of existing experimental data. For slow processes, a limiting solution for maximum pressure in oil shale rocks has been obtained. Generation of high pressures in rocks by thermal or other means may lead to rock fracture which may be taken advantage of in modified in-situ oil shale processing.

Gidaspow, D.; Lyczkowski, R.W.

1978-09-18T23:59:59.000Z

68

Continuous multi-phase feeding of broiler chickens  

E-Print Network (OSTI)

Continuous multi-phase feeding of broiler chickens was evaluated to optimize broiler nutrition and minimize environmental impact related to excess nitrogen in poultry manure. Four experiments were conducted. Experiments 1 and 2 studied effects of continuous multi-phase feeding during a 3-week starting period using battery brooders while experiments 3 and 4 evaluated multi-phase feeding during a traditional 7-week growing period using both battery brooders and floor pens. In the first and second experiments, the nutrient content of the multi-phase diets was changed every 24 hours in comparison to single-phase feeding. Results indicated that during the starter period, continuous multi-phase feeding had no significant influence on feed consumption, daily gain, feed to gain ratio or fecal nitrogen. In the third and fourth experiments, a four phase industry type broiler feeding program was compared to intensive multi-phase feeding programs created by linearly blending three different diets based on typical industry nutrient values and a commercial nutrient modeling computer program (EFG Natal®). In both intensive multi-phase feeding programs, the diets were changed every three days over a 7-week growth period. Broilers in experiment 3 were raised in Petersime battery brooders to primarily access nitrogen balance while birds in experiment 4 were raised in a floor pen on pine shaving litter to resemble commercial broiler production. The results indicated that intensive multi-phase feeding improved body weight gain and feed to gain ratio only in weeks 5 and 6 but not during the overall 7-week period. Nitrogen excretion and nitrogen retention were unaffected by the intensive multi-phase feeding systems. Economic analysis indicated that intensive multi-phase feeding programs could potentially lower feed costs per kilogram of gain. However, the high cost of implementing a continuous multi-phase feeding system may not justify the relatively small gain in lower feed cost per kilogram of gain. In conclusion, continuous multi-phase feeding of broiler chickens using corn-soy diets does not appear to be justified by either increased performance or reduced nitrogen excretion.

Nasril

2003-12-01T23:59:59.000Z

69

A model for multiphase flows through poroelastic media  

Science Conference Proceedings (OSTI)

A continuum model for multiphase fluid mixture flows through poroelastic media is presented. The basic conservation laws developed via a volume averaging technique are considered. Effects of phasic equilibrated forces are included in the model. Based on the thermodynamics of the multiphase mixture flows, appropriate constitutive equations are formulated. The entropy inequality is exploited, and the method of Lagrangian multiplier is used along with the phasic conservation laws to derive the constitutive equations for the phasic stress tensors, equilibrated stress vectors, and the interactions terms. The special cases of wave propagation in poroelastic media saturated with multiphase fluids, and multiphase flows through porous media, are studied. It is shown that the present theory leads to the extended Darcy’s law and contains, as a special case, Biot’s theory of saturated poroelastic media.

Ahmadi, Goodarz; Mazaheri, Ali Reza; Smith, D.H

2003-01-01T23:59:59.000Z

70

Multiphase Flow Dynamics 4: Nuclear Thermal Hydraulics, 1st edition  

Science Conference Proceedings (OSTI)

Volume 4 of the successful book package "Multiphase Flow" is devoted to nuclear thermal hydraulics which is a substantial part of nuclear reactor safety. It provides knowledge and mathematical tools for adequate description of the process of transferring ...

Nikolay I. Kolev

2009-06-01T23:59:59.000Z

71

NETL Publications: 2013 NETL Workshop on Multiphase Flow Science  

NLE Websites -- All DOE Office Websites (Extended Search)

2013 NETL Workshop on Multiphase Flow Science 2013 NETL Workshop on Multiphase Flow Science Tuesday, August 6, 2013 - Governors Ballroom, Lakeview Resort Registration (Grand Ballroom Foyer) Welcome and Introduction (Governors Ballroom) William Rogers, Leader - Multiphase Flow Team U.S. Department of Energy, National Energy Technology Laboratory NETL Multiphase Flow Research Overview Madhava Syamlal, Focus Area Leader - Computational and Basic Science Focus Area U.S. Department of Energy, National Energy Technology Laboratory Session Chair - Rahul Garg Application of a Filtered Euler-Lagrange Formalism to Large-Scale Simulations of Dilute and Dense Fluid-Particle Flows Jesse Capecelatro and Olivier Desjardins, Cornell University Heat Transfer in Fluidized Bed-Tube Heat Exchanger Amit Amritkar and DaneshTafti, Virginia Tech

72

Proceedings of the workshop on geochemical modeling  

SciTech Connect

The following collection of papers was presented at a workshop on geochemical modeling that was sponsored by the Office of Civilian Radioactive Waste Management Program at the Lawrence Livermore National Laboratory (LLNL). The LLNL Waste Management Program sponsored this conference based on their belief that geochemical modeling is particularly important to the radioactive waste disposal project because of the need to predict the consequences of long-term water-rock interactions at the proposed repository site. The papers included in this volume represent a subset of the papers presented at the Fallen Leaf Lake Conference and cover a broad spectrum of detail and breadth in a subject that reflects the diverse research interests of the conference participants. These papers provide an insightful look into the current status of geochemical modeling and illustrate how various geochemical modeling codes have been applied to problems of geochemical interest. The emphasis of these papers includes traditional geochemical modeling studies of individual geochemical systems, the mathematical and theoretical development and refinement of new modeling capabilities, and enhancements of data bases on which the computations are based. The papers in this proceedings volume have been organized into the following four areas: Geochemical Model Development, Hydrothermal and Geothermal Systems, Sedimentary and Low Temperature Environments, and Data Base Development. The participants of this symposium and a complete list of the talks presented are listed in the appendices.

Not Available

1986-01-01T23:59:59.000Z

73

A geochemical expert system prototype using object-oriented knowledge representation and a production rule system  

Science Conference Proceedings (OSTI)

Keywords: MINEQL, artificial intelligence, expert systems, geochemical expert system, geochemical modeling, geochemistry

Forrest M. Hoffman; Vijay S. Tripathi

1993-01-01T23:59:59.000Z

74

NETL: 2009 Conference Proceedings - NETL 2009 Workshop on Multiphase Flow  

NLE Websites -- All DOE Office Websites (Extended Search)

NETL 2009 Workshop on Multiphase Flow Science NETL 2009 Workshop on Multiphase Flow Science Euro-Suites Hotel, Morgantown, WV April 22-23, 2009 Table of Contents Disclaimer Presentations Technology Roadmap, Workshop on Multiphase Flow Research, June 6-7, 2006 [PDF-45KB] Final Attendee List [PDF-21KB] PRESENTATIONS Kinetic Theory of Polydisperse Granular Flows and Validation Data [PDF-526KB] Christine Hrenya, Colorado University Quadrature-Based Moment Methods for Polydisperse Gas-Solid Flows [PDF-3.7MB] Rodney Fox, Iowa State University Fluid-Particle Drag Force in Bidisperse Suspensions [PDF-4.2MB] Sankaran Sundaresan, Princeton University Modeling Particle-Fluid Momentum Transfer in Polydisperse Gas-Solid Flows through Direct Numerical Simulations Based on the Immersed Boundary Method [PDF-2MB] Shankar Subramaniam, Iowa State University

75

National laboratories` capabilities summaries for the DOE Virtual Center for Multiphase Dynamics (VCMD)  

SciTech Connect

The Virtual Center For Multiphase Dynamics (VCMD) integrates and develops the resources of industry, government, academia, and professional societies to enable reliable analysis in multiphase computational fluid dynamics. The primary means of the VCMD focus will be by the creation, support, and validation of a computerized simulation capability for multiphase flow and multiphase flow applications. This paper briefly describes the capabilities of the National Laboratories in this effort.

Joyce, E.L.

1997-03-01T23:59:59.000Z

76

Comparison of approaches for simulating reactive solute transport involving organic degradation reactions by multiple terminal electron acceptors  

Science Conference Proceedings (OSTI)

Reactive solute transport models are useful tools for analyzing complex geochemical behavior resulting from biodegradation of organic compounds by multiple terminal electron acceptors (TEAPs). The usual approach of simulating the reactions of multiple ... Keywords: biogeochemistry, groundwater, hydrogen, monod kinetics, thermodynamics

Gary P. Curtis

2003-04-01T23:59:59.000Z

77

Multiphase Flow Modeling of Biofuel Production Processes  

Science Conference Proceedings (OSTI)

As part of the Idaho National Laboratory's (INL's) Secure Energy Initiative, the INL is performing research in areas that are vital to ensuring clean, secure energy supplies for the future. The INL Hybrid Energy Systems Testing (HYTEST) Laboratory is being established to develop and test hybrid energy systems with the principal objective to safeguard U.S. Energy Security by reducing dependence on foreign petroleum. HYTEST involves producing liquid fuels in a Hybrid Energy System (HES) by integrating carbon-based (i.e., bio-mass, oil-shale, etc.) with non-carbon based energy sources (i.e., wind energy, hydro, geothermal, nuclear, etc.). Advances in process development, control and modeling are the unifying vision for HES. This paper describes new modeling tools and methodologies to simulate advanced energy processes. Needs are emerging that require advanced computational modeling of multiphase reacting systems in the energy arena, driven by the 2007 Energy Independence and Security Act, which requires production of 36 billion gal/yr of biofuels by 2022, with 21 billion gal of this as advanced biofuels. Advanced biofuels derived from microalgal biomass have the potential to help achieve the 21 billion gal mandate, as well as reduce greenhouse gas emissions. Production of biofuels from microalgae is receiving considerable interest due to their potentially high oil yields (around 600 gal/acre). Microalgae have a high lipid content (up to 50%) and grow 10 to 100 times faster than terrestrial plants. The use of environmentally friendly alternatives to solvents and reagents commonly employed in reaction and phase separation processes is being explored. This is accomplished through the use of hydrothermal technologies, which are chemical and physical transformations in high-temperature (200-600 C), high-pressure (5-40 MPa) liquid or supercritical water. Figure 1 shows a simplified diagram of the production of biofuels from algae. Hydrothermal processing has significant advantages over other biomass processing methods with respect to separations. These 'green' alternatives employ a hybrid medium that, when operated supercritically, offers the prospect of tunable physicochemical properties. Solubility can be rapidly altered and phases partitioned selectively to precipitate or dissolve certain components by altering temperature or pressure in the near-critical region. The ability to tune the solvation properties of water in the highly compressible near-critical region facilitates partitioning of products or by-products into separate phases to separate and purify products. Since most challenges related to lipid extraction are associated with the industrial scale-up of integrated extraction systems, the new modeling capability offers the prospect of addressing previously untenable scaling issues.

D. Gaston; D. P. Guillen; J. Tester

2011-06-01T23:59:59.000Z

78

Up-Scaling Geochemical Reaction Rates for Carbon Dioxide (CO2) in Deep Saline Aquifers  

Science Conference Proceedings (OSTI)

The overall goal of the project was to bridge the gap between our knowledge of small-scale geochemical reaction rates and reaction rates meaningful for modeling transport at core scales. The working hypothesis was that reaction rates, determined from laboratory measurements based upon reactions typically conducted in well mixed batch reactors using pulverized reactive media may be significantly changed in in situ porous media flow due to rock microstructure heterogeneity. Specifically we hypothesized that, generally, reactive mineral surfaces are not uniformly accessible to reactive fluids due to the random deposition of mineral grains and to the variation in flow rates within a pore network. Expected bulk reaction rates would therefore have to be correctly up-scaled to reflect such heterogeneity. The specific objective was to develop a computational tool that integrates existing measurement capabilities with pore-scale network models of fluid flow and reactive transport. The existing measurement capabilities to be integrated consisted of (a) pore space morphology, (b) rock mineralogy, and (c) geochemical reaction rates. The objective was accomplished by: (1) characterizing sedimentary sandstone rock morphology using X-ray computed microtomography, (2) mapping rock mineralogy using back-scattered electron microscopy (BSE), X-ray dispersive spectroscopy (EDX) and CMT, (3) characterizing pore-accessible reactive mineral surface area, and (4) creating network models to model acidic CO{sub 2} saturated brine injection into the sandstone rock samples.

Lindquist, W Brent

2009-03-03T23:59:59.000Z

79

Geochemical Enhancement Of Enhanced Geothermal System Reservoirs: An Integrated Field And Geochemical Approach  

DOE Green Energy (OSTI)

The geochemical effects of injecting fluids into geothermal reservoirs are poorly understood and may be significantly underestimated. Decreased performance of injection wells has been observed in several geothermal fields after only a few years of service, but the reasons for these declines has not been established. This study had three primary objectives: 1) determine the cause(s) of the loss of injectivity; 2) utilize these observations to constrain numerical models of water-rock interactions; and 3) develop injection strategies for mitigating and reversing the potential effects of these interactions. In this study rock samples from original and redrilled injection wells at Coso and the Salton Sea geothermal fields, CA, were used to characterize the mineral and geochemical changes that occurred as a result of injection. The study documented the presence of mineral scales and at both fields in the reservoir rocks adjacent to the injection wells. At the Salton Sea, the scales consist of alternating layers of fluorite and barite, accompanied by minor anhydrite, amorphous silica and copper arsenic sulfides. Amorphous silica and traces of calcite were deposited at Coso. The formation of silica scale at Coso provides an example of the effects of untreated (unacidified) injectate on the reservoir rocks. Scanning electron microscopy and X-ray diffractometry were used to characterize the scale deposits. The silica scale in the reservoir rocks at Coso was initially deposited as spheres of opal-A 1-2 micrometers in diameter. As the deposits matured, the spheres coalesced to form larger spheres up to 10 micrometer in diameter. Further maturation and infilling of the spaces between spheres resulted in the formation of plates and sheets that substantially reduce the original porosity and permeability of the fractures. Peripheral to the silica deposits, fluid inclusions with high water/gas ratios provide a subtle record of interactions between the injectate and reservoir rocks. In contrast, fluid inclusions trapped prior to injection are relatively gas rich. These results suggest that the rocks undergo extensive microfracturing during injection and that the composition of the fluid inclusions will be biased toward the youngest event. Interactions between the reservoir rocks and injectate were modeled using the non-isothermal reactive geochemical transport code TOUGHREACT. Changes in fluid pH, fracture porosity, fracture permeability, fluid temperature, and mineral abundances were monitored. The simulations predict that amorphous silica will precipitate primarily within a few meters of the injection well and that mineral deposition will lead to rapid declines in fracture porosity and permeability, consistent with field observations. In support of Enhanced Geothermal System development, petrologic studies of Coso well 46A-19RD were conducted to determine the regions that are most likely to fail when stimulated. These studies indicate that the most intensely brecciated and altered rocks in the zone targeted for stimulation (below 10,000 ft (3048 m)) occur between 11,200 and 11,350 ft (3414 and 3459 m). This zone is interpreted as a shear zone that initially juxtaposed quartz diorite against granodiorite. Strong pervasive alteration and veining within the brecciated quartz diorite and granodiorite suggest this shear zone was permeable in the past. This zone of weakness was subsequently exploited by a granophyre dike whose top occurs at 11,350 ft (3459 m). The dike is unaltered. We anticipate, based on analysis of the well samples that failure during stimulation will most likely occur on this shear zone.

Joseph N. Moore

2007-12-31T23:59:59.000Z

80

NETL: News Release - NETL's Multiphase Flow Research Group Wins INCITE  

NLE Websites -- All DOE Office Websites (Extended Search)

December 19, 2008 December 19, 2008 NETL's Multiphase Flow Research Group Wins INCITE Award Award Brings 13,000,000 Processor Hours for Design of Clean and Efficient Coal Gasifiers Morgantown, W.Va. - The Multiphase Flow Research Group at the National Energy Technology Laboratory (NETL) has won a 2009 Innovative and Novel Computational Impact on Theory and Experiment (INCITE) award from the U.S. Department of Energy for their proposal "Clean and Efficient Coal Gasifier Designs using Large-Scale Simulations." This is the second consecutive year that the team has won an INCITE award. The NETL project is one of 66 to receive INCITE awards for 2009. According to the Energy Department's Office of Science, the projects address "some of the greatest scientific challenges" and will receive access to "some of the world's most powerful supercomputers."

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81

Impact of wettability correlations on multiphase flow through porous media  

E-Print Network (OSTI)

In the last decades, significant progress has been made in understanding the multiphase displacement through porous media with homogeneous wettability and its relation to the pore geometry. However, the role of wettability at the scale of the pore remains still little understood. In the present study the displacement of immiscible fluids through a two-dimensional porous medium is simulated by means of a mesoscopic particle approach. The substrate is described as an assembly of non-overlapping circular disks whose preferential wettability is distributed according to prescribed spatial correlations, from pore scale up to domains at system size. We analyze how this well-defined heterogeneous wettability affects the flow and try to establish a relationship among wettability-correlations and large-scale properties of the multiphase flow.

Marta S. de La Lama; Martin Brinkmann

2012-05-31T23:59:59.000Z

82

System for measuring multiphase flow using multiple pressure differentials  

DOE Patents (OSTI)

An improved method and system for measuring a multi-phase flow in a pressure flow meter. An extended throat venturi is used and pressure of the multi-phase flow is measured at three or more positions in the venturi, which define two or more pressure differentials in the flow conduit. The differential pressures are then used to calculate the mass flow of the gas phase, the total mass flow, and the liquid phase. The system for determining the mass flow of the high void fraction fluid flow and the gas flow includes taking into account a pressure drop experienced by the gas phase due to work performed by the gas phase in accelerating the liquid phase.

Fincke, James R. (Idaho Falls, ID)

2003-01-01T23:59:59.000Z

83

REACTIVE MULTIPHASE BEHAVIOR OF CO2 IN SALINE AQUIFERS BENEATH THE COLORADO PLATEAU  

DOE Green Energy (OSTI)

Field and laboratory investigations of naturally occurring CO{sub 2}-reservoirs are being conducted to determine the characteristics of potential seal and reservoir units and the extent of the interactions that occur between the host rocks and the CO{sub 2} charged fluids. Efforts have focused on the Farnham Dome field, located in central Utah, the Springerville-St. Johns field in Arizona and New Mexico, and most recently, the Crystal Geyser-Salt Wash graben areas with their CO{sub 2}-charged geysers and springs in central Utah. At both the Springerville-St. Johns field and the central Utah CO{sub 2} spring area, there is evidence of extensive travertine deposits that document release of CO{sub 2} to the atmosphere. At Farnham Dome, calcite debris fields appear to be remnants of vein calcite and an earlier period of fluid leakage. The main achievements during this quarter are (1): preparation for a soil gas flux survey in October at the Crystal Geyser --Little Grand Wash fault zone, and the Salt Wash graben; (2) submission of an abstract to the upcoming Measurement, Monitoring and Verification session at the Fall AGU meeting; (3) submission of an invited abstract to the Gordon Conference on Hydrocarbon Resources; and (4) receipt of initial radiocarbon dates of travertine from the Springerville-St Johns field. Analytical results and interpretations of both the travertine deposition and the soil gas surveys are still in progress, and will be included in future quarterly reports.

R.G. Allis; J. Moore; S. White

2004-10-25T23:59:59.000Z

84

REACTIVE MULTIPHASE BEHAVIOR OF CO{sub 2} IN SALINE AQUIFERS BENEATH THE COLORADO PLATEAU  

DOE Green Energy (OSTI)

Soil gas surveys have been carried out on the Colorado Plateau over areas with natural occurrences of CO{sub 2}. At Farnham Dome, Utah, and Springerville-St. Johns, Arizona, proven CO{sub 2} reservoirs occur at 600-800 m depth, but no anomalous soil gas CO{sub 2} flux was detected. Background CO{sub 2} fluxes of up to about 5 g m{sup -2} day{sup -1} were common in arid, poorly vegetated areas, and fluxes up to about 20 g m{sup -2} day{sup -1} were found at Springerville-St. Johns in heavily vegetated, wet ground adjacent to springs. These elevated fluxes are attributed to shallow root zone activity rather than to a deep upflow of CO{sub 2}. Localized areas of anomalously high CO{sub 2} gas flux ({approx} 100 g m{sup -2} day{sup -1}) were documented along the Little Grand Wash Fault Zone near Crystal Geyser, Utah and nearby in Ten Mile Graben, but those in Ten Mile Graben are not directly associated with the major faults. In both areas, features with a visible gas flux are present. Isotopic measurements on the CO{sub 2} gas confirm that it originated at depth. Evidence of widespread vein calcite at the surface at Farnham Dome and travertine deposits in the other areas suggests that there has been an outflow of CO{sub 2}-rich fluids in the past. 14C ages of pollen trapped in the travertine at Springerville-St. Johns record a period of CO{sub 2} leakage to the atmosphere between 887 {+-} 35 and 3219 {+-} 30 years BP. No travertine deposits appear to be currently forming. At Springerville-St. Johns, Crystal Geyser and Ten Mile Graben, there are significant outflows of high-bicarbonate water. Movement of CO{sub 2}-rich groundwaters may be the dominant mechanism controlling the mobility of CO{sub 2} today. The very localized nature of the soil gas anomalies, evidence of large scale discharge of CO{sub 2} over a very short period of time and the outflow of ground water containing dissolved CO{sub 2} will present challenges for effective, long term monitoring of CO{sub 2} leakage.

R.G. Allis; J. Moore; S. White

2005-02-08T23:59:59.000Z

85

Numerical Modeling of Reactive Multiphase Flow for FCC and Hot Gas Desulfurization Circulating Fluidized Beds  

Science Conference Proceedings (OSTI)

This work was carried out to understand the behavior of the solid and gas phases in a CFB riser. Only the riser is modeled as a straight pipe. A model with linear algebraic approximation to solids viscosity of the form, {musubs} = 5.34{epsisubs}, ({espisubs} is the solids volume fraction) with an appropriate boundary condition at the wall obtained by approximate momentum balance solution at the wall to acount for the solids recirculation is tested against experimental results. The work done was to predict the flow patterns in the CFB risers from available experimental data, including data from a 7.5-cm-ID CFB riser at the Illinois Institute of Technology and data from a 20.0-cm-ID CFB riser at the Particulate Solid Research, Inc., facility. This research aims at modeling the removal of hydrogen sulfide from hot coal gas using zinc oxide as the sorbent in a circulating fluidized bed and in the process indentifying the parameters that affect the performance of the sulfidation reactor. Two different gas-solid reaction models, the unreacted shrinking core (USC) and the grain model were applied to take into account chemical reaction resistances. Also two different approaches were used to affect the hydrodynamics of the process streams. The first model takes into account the effect of micro-scale particle clustering by adjusting the gas-particle drag law and the second one assumes a turbulent core with pseudo-steady state boundary condition at the wall. A comparison is made with experimental results.

None

2005-07-01T23:59:59.000Z

86

REACTIVE MULTIPHASE BEHAVIOR OF CO2 IN SALINE AQUIFERS BENEATH THE COLORADO PLATEAU  

Science Conference Proceedings (OSTI)

The six coal-fired power plants located in the Colorado Plateau and southern Rocky Mountain region of the U.S. produce 100 million tons of CO{sub 2} per year. Thick sequences of collocated sedimentary rocks represent potential sites for sequestration of the CO{sub 2}. Field and laboratory investigations of naturally occurring CO{sub 2}-reservoirs are being conducted to determine the characteristics of potential seal and reservoir units and the extent of the interactions that occur between the host rocks and the CO{sub 2} charged fluids. The results are being incorporated into a series of two-dimensional numerical models that represent the major chemical and physical processes induced by injection. During reporting period covered here (March 30 to June 30, 2003), the main achievements were: Presentation of three papers at the Second Annual Conference on Carbon Sequestration (May 5-8, Alexandria, Virginia); Presentation of a poster at the American Association of Petroleum Geologists meeting; Co-PI organized and chaired a special session on Geologic Carbon Dioxide Sequestration at the American Association of Petroleum Geologists annual convention in Salt Lake City (May 12-15).

R.G. Allis; J. Moore; S. White

2003-06-30T23:59:59.000Z

87

REACTIVE MULTIPHASE BEHAVIOR OF CO2 IN SALINE AQUIFERS BENEATH THE COLORADO PLATEAU  

Science Conference Proceedings (OSTI)

Soil CO{sub 2} flux surveys have been conducted over known CO{sub 2} reservoirs at Farnham Dome, Utah, Crystal Geyser-Ten Mile Graben in Utah and Springerville-St. Johns, Arizona. No anomalous CO{sub 2} flux was detected at the Farnham Dome and Springerville-St. Johns. At Crystal Geyser-Ten Mile Graben, localized areas of anomalously high CO{sub 2} flux ({approx}100 g m{sup -2} day{sup -1}) occur along a fault zone near visibly degassing features. Isotopic measurements on CO{sub 2} collected from nearby springs indicate that it originated at depth. Evidence of widespread vein calcite at the surface (Farnham Dome) and travertine deposits at the other two areas suggests that discharge of CO{sub 2}-rich fluids has occurred in the past. Despite the lack of evidence for significant present day leakage of CO{sub 2} to the atmosphere at Springerville-St. Johns and Crystal Geyser-Ten Mile Graben, there are significant outflows of high-bicarbonate water in both areas suggesting continuous migration of CO{sub 2} in the aqueous phase from depth. The very localized nature of the CO{sub 2} flux anomalies, and the outflow of ground water containing dissolved CO{sub 2} present challenges for effective, long term monitoring of CO{sub 2} leakage.

R.G. Allis; J. Moore; S. White

2005-05-16T23:59:59.000Z

88

Corrosion-induced gas generation in a nuclear waste repository: Reactive geochemistry and multiphase flow effect  

E-Print Network (OSTI)

and 80 0 C. Applied Geochemistry, 13, 905-916. Brown, P.W. ,and 80 0 C. Applied Geochemistry, 13, 905-916. de Combarieu,cells. Applied Geochemistry, 21, 977-992. Finsterle, S. ,

Xu, T.

2009-01-01T23:59:59.000Z

89

The Existence of a Multi-Phase Critical Point in Metastable Fcc ...  

Science Conference Proceedings (OSTI)

Presentation Title, The Existence of a Multi-Phase Critical Point in Metastable Fcc Ordering Phase Diagrams and Its Influence on Phase Diagram Features, ...

90

Towards Development of a Multiphase Simulation Model Using Lattice Boltzmann Method (LBM).  

E-Print Network (OSTI)

??Lattice Boltzmann Method is evolving as a substitute to the prevalent and predominant CFD modeling especially in cases such as multiphase flows, porous media flows… (more)

Koosukuntla, Narender Reddy

2011-01-01T23:59:59.000Z

91

Pore-scale modeling of the impact of surrounding flow behavior on multiphase flow properties.  

E-Print Network (OSTI)

??Accurate predictions of macroscopic multiphase flow properties, such as relative permeability and capillary pressure, are necessary for making key decisions in reservoir engineering. These properties… (more)

Petersen, Robert Thomas

2010-01-01T23:59:59.000Z

92

An unstructured finite volume simulator for multiphase flow through fractured-porous media.  

E-Print Network (OSTI)

??Modeling of multiphase flow in fractured media plays an integral role in management and performance prediction of oil and gas reserves. Geological characterization and nmultiphase… (more)

Bajaj, Reena

2009-01-01T23:59:59.000Z

93

Parameter estimation from flowing fluid temperature logging data in unsaturated fractured rock using multiphase inverse modeling  

E-Print Network (OSTI)

modeling fluid and heat flow in fractured porous media, Soc.fluid and heat flows of multiphase, multicomponent fluid mixtures in porous and fractured media.

Mukhopadhyay, S.

2009-01-01T23:59:59.000Z

94

Efficient Schemes for Reducing Numerical Dispersion in Modeling Multiphase Transport through Porous and Fractured Media  

E-Print Network (OSTI)

involved. These heat-transfer processes are complicated byprocesses of multiphase flow, chemical transport, and heat transfertransport, and heat transfer, we assume that these processes

Wu, Yu-Shu; Forsyth, Peter A.

2006-01-01T23:59:59.000Z

95

NUREG/CR-6870 Consideration of Geochemical  

E-Print Network (OSTI)

mining and milling of uranium ore. Nonetheless, the use of leaching fluids to mine uranium contaminatesNUREG/CR-6870 Consideration of Geochemical Issues in Groundwater Restoration at Uranium In in Groundwater Restoration at Uranium In-Situ Leach Mining Facilities Manuscript Completed: December 2006 Date

96

NETL: Methane Hydrates - DOE/NETL Projects  

NLE Websites -- All DOE Office Websites (Extended Search)

TOUGHREACT, a geochemical code for simulating chemically reactive non-isothermal flows of multiphase fluids in porous and fractured media; and C.CANDI, a code used to describe...

97

Geochemical engineering problem identification and program description. Final report  

SciTech Connect

The Geochemical Engineering Program has as its goal the improvement of geochemical fluid management techniques. This document presents the strategy and status of the Geochemical Engineering Program. The magnitude and scope of geochemical-related problems constraining geothermal industry productivity are described. The goals and objectives of the DGE Geochemical Engineering Program are defined. The rationale and strategy of the program are described. The structure, priorities, funding, and management of specific elements within the program are delineated, and the status of the overall program is presented.

Crane, C.H.; Kenkeremath, D.C.

1981-05-01T23:59:59.000Z

98

Multi-phase back contacts for CIS solar cells  

DOE Patents (OSTI)

Multi-phase, single layer, non-interdiffusing M-Mo back contact metallized films, where M is selected from Cu, Ga, or mixtures thereof, for CIS cells are deposited by a sputtering process on suitable substrates, preferably glass or alumina, to prevent delamination of the CIS from the back contact layer. Typical CIS compositions include CuXSe{sub 2} where X is In or/and Ga. The multi-phase mixture is deposited on the substrate in a manner to provide a columnar microstructure, with micro-vein Cu or/and Ga regions which partially or fully vertically penetrate the entire back contact layer. The CIS semiconductor layer is then deposited by hybrid sputtering and evaporation process. The Cu/Ga-Mo deposition is controlled to produce the single layer two-phase columnar morphology with controllable Cu or Ga vein size less than about 0.01 microns in width. During the subsequent deposition of the CIS layer, the columnar Cu/Ga regions within the molybdenum of the Cu/Ga-Mo back layer tend to partially leach out, and are replaced by columns of CIS. Narrower Cu and/or Ga regions, and those with fewer inner connections between regions, leach out more slowly during the subsequent CIS deposition. This gives a good mechanical and electrical interlock of the CIS layer into the Cu/Ga-Mo back layer. Solar cells employing In-rich CIS semiconductors bonded to the multi-phase columnar microstructure back layer of this invention exhibit vastly improved photo-electrical conversion on the order of 17% greater than Mo alone, improved uniformity of output across the face of the cell, and greater Fill Factor. 15 figs.

Rockett, A.A.; Yang, L.C.

1995-12-19T23:59:59.000Z

99

Interfacial Pressures and Shocks in a Multiphase Flow mix Model  

Science Conference Proceedings (OSTI)

Multiphase flow models have been proposed for use in situations which have combined Rayleigh-Taylor (RTI) and Richtmyer-Meshkov (RMI) instabilities [2, 3]. Such an approach works poorly for the case of a heavy to light shock incidence on a developed interface. I suggest that this difficulty can be overcome by adding an additional source to the turbulence kinetic energy equation. A variety of constraints on such a source are considered. In this context it is observed that a new constraint on closures arises. This occurs because of the discontinuity within the shock responsible for the RMI. The proposed model (Shock Scattering) is shown to give useful results.

Klem, D E

2004-10-01T23:59:59.000Z

100

A finite element approach for multiphase fluid flow in porous media  

Science Conference Proceedings (OSTI)

The main scope of this work is to carry out a mathematical framework and its corresponding finite element (FE) discretization for the partially saturated soil consolidation modelling in presence of an immiscible pollutant. A multiphase system with the ... Keywords: Consolidation, Finite elements, Immiscible pollutants, Mixture theory, Multiphase porous media

Javier L. Mroginski; H.Ariel Di Rado; Pablo A. Beneyto; Armando M. Awruch

2010-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "multiphase reactive geochemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

An energy preserving formulation for the simulation of multiphase turbulent flows  

Science Conference Proceedings (OSTI)

In this manuscript we propose an energy preserving formulation for the simulation of multiphase flows. The new formulation reduces the numerical diffusion with respect to previous formulations dealing with multiple phases, which makes this method to ... Keywords: Advection scheme, Multiphase flows, Turbulence

D. Fuster

2013-02-01T23:59:59.000Z

102

A Lagrangian, stochastic modeling framework for multi-phase flow in porous media  

Science Conference Proceedings (OSTI)

Many of the complex physical processes relevant for compositional multi-phase flow in porous media are well understood at the pore-scale level. In order to study CO"2 storage in sub-surface formations, however, it is not feasible to perform simulations ... Keywords: Lagrangian approach, Multi-phase flow, PDF method, Porous media, Stochastic particle method

Manav Tyagi; Patrick Jenny; Ivan Lunati; Hamdi A. Tchelepi

2008-06-01T23:59:59.000Z

103

Multiscale finite-volume method for compressible multiphase flow in porous media  

Science Conference Proceedings (OSTI)

The Multiscale Finite-Volume (MSFV) method has been recently developed and tested for multiphase-flow problems with simplified physics (i.e. incompressible flow without gravity and capillary effects) and proved robust, accurate and efficient. However, ... Keywords: compressibility, finite-volume methods, multiphase flow in porous media, multiscale methods, reservoir simulation

Ivan Lunati; Patrick Jenny

2006-08-01T23:59:59.000Z

104

A variational multiscale finite element method for multiphase flow in porous media  

Science Conference Proceedings (OSTI)

We present a stabilized finite element method for the numerical solution of multiphase flow in porous media, based on a multiscale decomposition of pressures and fluid saturations into resolved (or grid) scales and unresolved (or subgrid) scales. The ... Keywords: Conservation laws, Finite elements, Multiphase flow, Porous media, Shocks, Stabilized methods, Variational multiscale, Waterflood

Ruben Juanes

2005-04-01T23:59:59.000Z

105

A variational multiscale finite element method for multiphase flow in porous media  

Science Conference Proceedings (OSTI)

We present a stabilized finite element method for the numerical solution of multiphase flow in porous media, based on a multiscale decomposition of pressures and fluid saturations into resolved (or grid) scales and unresolved (or subgrid) scales. The ... Keywords: conservation laws, finite elements, multiphase flow, porous media, shocks, stabilized methods, variational multiscale, waterflood

Ruben Juanes

2005-04-01T23:59:59.000Z

106

A simulation model for the fabrication of components made from multiphase perfect materials  

Science Conference Proceedings (OSTI)

A component, which has an optimized combination of different materials (including homogeneous materials and different types of heterogeneous materials) in its different portions for a specific application, is considered as the component made of a multiphase ... Keywords: Layered manufacturing, Multiphase perfect materials, Simulation, Virtual component, Virtual manufacturing

Feng Wang; Ke-Zhang Chen; Xin-An Feng

2008-08-01T23:59:59.000Z

107

Experimental Geochemical Studies Relevant to Carbon Sequestration  

NLE Websites -- All DOE Office Websites (Extended Search)

Geochemical Studies Relevant to Geochemical Studies Relevant to Carbon Sequestration James G. Blencoe (blencoejg@ornl.gov; 865-574-7041) David R. Cole (coledr@ornl.gov; 865-574-5473) Juske Horita (horitaj@ornl.gov; 865-576-2750) Geochemistry Group Chemical and Analytical Sciences Division Oak Ridge National Laboratory P.O. Box 2008, Building 4500-S Oak Ridge, TN 37831-6110 Gerilynn R. Moline (molinegr@ornl.gov; 865-576-5134) Environmental Sciences Division Oak Ridge National Laboratory P.O. Box 2008, Building 1505 Oak Ridge, TN 37831-6038 Introduction Evidence is mounting that rising levels of atmospheric CO 2 will have profound effects on future global climates (1-2) . Consequently, many experts agree that technologies are needed to slow, and ultimately stop, further buildup (3-5) . One of the strategies proposed to achieve this aim

108

Fladmark. Parallel simulation of multiphase/multicomponent flow models  

E-Print Network (OSTI)

Summary. The simulation of flow in porous media is a computationally demanding task. Thermodynamical equilibrium calculations and complex, heterogeneous geological structures normally gives a multiphysics/multidomain problem to solve. Thus, efficient solution methods are needed. The research simulator Athena is a 3D, multiphase, multicomponent, porous media flow simulator. A parallel version of the simulator was developed based on a non-overlapping domain decomposition strategy, where the domains are defined a-priori from e.g. geological data. Selected domains are refined with locally matching grids, giving a globally non-matching, unstructured grid. In addition to the space domain, novel algorithms for parallel processing in time based on a predictor-corrector strategy has been successfully implemented. We discuss how the domain decomposition framework can be used to include different physical and numerical models in selected sub-domains. Also we comment on how the two-level solver relates to multiphase upscaling techniques. Adding communication functionality enables the original serial version to run on each sub-domain in parallel. Motivated by the need for larger time steps, an implicit formulation of the mass transport equations has been formulated and implemented in the existing parallel framework. Further, as the Message Passing Interface (MPI) is used for communication, the simulator is highly portable. Through benchmark experiments, we test the new formulation on platforms ranging from commercial super-computers to heterogeneous networks of workstations. 1

Erlend Řian; Magne S. Espedal; I. Garrido; G. E. Fladmark

2004-01-01T23:59:59.000Z

109

Interface effects on multiphase flows in porous media  

Science Conference Proceedings (OSTI)

Most models for multiphase flows in a porous medium are based on the straightforward extension of Darcy's law, in which each fluid phase is driven by its own pressure gradient. The pressure difference between the phases is thought to be an effect of surface tension and is called capillary pressure. Independent of Darcy's law, for liquid imbibition processes in a porous material, diffusion models are sometime used. In this paper, an ensemble phase averaging technique for continuous multi phase flows is applied to derive averaged equations and to examine the validity of the commonly used models. The closure for the averaged equations is quite complicated for general multiphase flows in a porous material. For flows with a small ratio of the characteristic length of the phase interfaces to the macroscopic length, the closure relations can be simplified significantly by an approximation with a second order error in the length ratio. The approximation reveals the information of the length scale separation obscured during the ensemble averaging process, and leads to an equation system similar to Darcy's law, but with additional terms. Based on interactions on phase interfaces, relations among closure quantities are studied.

Zhang, Duan Z [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

110

Modeling of thermal transport properties of multiphase porous materials  

Science Conference Proceedings (OSTI)

This work presents a numerical framework for modeling thermal transport properties of multiphase porous materials with complex internal microstructures. The framework includes two steps. First, a random generation-growth algorithm is highlighted for reproducing multiphase microstructures, statistically equivalent to the actual systems, based on the geometrical and morphological information obtained from measurements and experimental estimations. Then a high-efficiency lattice Boltzmann solver for the corresponding governing equations is described, which, while assuring energy conservation and appropriate continuities at the interfaces in a complex system, has demonstrated its numerical power in yielding accurate solutions. Various applications are provided to validate the feasibility, effectiveness and robustness of this new framework by comparing the predictions with existing experimental data for different transport processes, accounting for the effects due to internal morphology, microstructural anisotropy, and multi phase interactions. The examples given also suggest potential applicability of this methodology to other problems as long as they are governed by similar partial differential equation(s). Thus, for given composition and structure, this numerical methodology is in essence a model built on sound physics principles with prior validity, without resorting to any ad hoc empirical treatment. Therefore, it is useful for design and optimization of new materials, beyond just predicting and analyzing the existing ones.

Wang, Moran [Los Alamos National Laboratory; Kang, Qinjun [Los Alamos National Laboratory; Robinson, Bruce [Los Alamos National Laboratory; Ning, Pan [UC DAVIS

2010-01-01T23:59:59.000Z

111

Category:Geochemical Data Analysis | Open Energy Information  

Open Energy Info (EERE)

source source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Category Edit History Facebook icon Twitter icon » Category:Geochemical Data Analysis Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Geothermalpower.jpg Looking for the Geochemical Data Analysis page? For detailed information on exploration techniques, click here. Category:Geochemical Data Analysis Add.png Add a new Geochemical Data Analysis Technique Pages in category "Geochemical Data Analysis" The following 3 pages are in this category, out of 3 total. G Geothermometry T Thermal Ion Dispersion Thermochronometry Retrieved from "http://en.openei.org/w/index.php?title=Category:Geochemical_Data_Analysis&oldid=689825"

112

Temporal Geochemical Variations In Volatile Emissions From Mount...  

Open Energy Info (EERE)

Temporal Geochemical Variations In Volatile Emissions From Mount St Helens, Usa, 1980-1994 Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Temporal...

113

Trace Element Geochemical Zoning in the Roosevelt Hot Springs...  

Open Energy Info (EERE)

Element Geochemical Zoning in the Roosevelt Hot Springs Thermal Area, Utah Abstract Chemical interaction of thermal brines with reservoir rock in the Roosevelt Hot Springs...

114

DNA-based methods of geochemical prospecting  

Science Conference Proceedings (OSTI)

The present invention relates to methods for performing surveys of the genetic diversity of a population. The invention also relates to methods for performing genetic analyses of a population. The invention further relates to methods for the creation of databases comprising the survey information and the databases created by these methods. The invention also relates to methods for analyzing the information to correlate the presence of nucleic acid markers with desired parameters in a sample. These methods have application in the fields of geochemical exploration, agriculture, bioremediation, environmental analysis, clinical microbiology, forensic science and medicine.

Ashby, Matthew (Mill Valley, CA)

2011-12-06T23:59:59.000Z

115

Uncertainty Quantification Tools for Multiphase Flow Simulations using MFIX  

NLE Websites -- All DOE Office Websites (Extended Search)

Uncertainty Uncertainty Quantification Tools for Multiphase Flow Simulations using MFIX X. Hu 1 , A. Passalacqua 2 , R. O. Fox 1 1 Iowa State University, Department of Chemical and Biological Engineering, Ames, IA 2 Iowa State University, Department of Mechanical Engineering, Ames, IA Project Manager: Steve Seachman University Coal Research and Historically Black Colleges and Universities and Other Minority Institutions Contractors Review Conference Pittsburgh, June 11 th - 13 th 2013 X. Hu, A. Passalacqua, R. O. Fox (ISU) Uncertainty quantification DOE-UCR Review Meeting 2013 1 / 44 Outline 1 Introduction and background 2 Project objectives and milestones 3 Technical progress Univariate case Multivariate case Code structure 4 Future work X. Hu, A. Passalacqua, R. O. Fox (ISU) Uncertainty quantification DOE-UCR Review Meeting 2013 2 / 44 Introduction and background Outline 1 Introduction

116

Iterative methods for solving the pressure problem at multiphase filtration  

E-Print Network (OSTI)

Applied problems of oil and gas recovery are studied numerically using the mathematical models of multiphase fluid flows in porous media. The basic model includes the continuity equations and the Darcy laws for each phase, as well as the algebraic expression for the sum of saturations. Primary computational algorithms are implemented for such problems using the pressure equation. In this paper, we highlight the basic properties of the pressure problem and discuss the necessity of their fulfillment at the discrete level. The resulting elliptic problem for the pressure equation is characterized by a non-selfadjoint operator. Possibilities of approximate solving the elliptic problem are considered using the iterative methods. Special attention is given to the numerical algorithms for calculating the pressure on parallel computers.

Vabishchevich, P

2011-01-01T23:59:59.000Z

117

A New Multiphase Model for Simulating Energetically Driven Particles  

SciTech Connect

The proper representation of particulate phenomena is important for the simulation of many non-ideal particle loaded explosives. These explosives present severe numerical difficulties to simulate because numerical approaches for packed particle beds often behave poorly for the dilute regime and the reverse is often true for methods developed for the dilute regime. This paper presents a multiphase framework for the simulation of these non-ideal explosives that accurately accounts for the particulate behavior in both of these regimes. The capability of this framework is enhanced by the use of prescribed PDF methods for both particle size distributions and the representation of chemical processes. We have validated this framework using several experimental methods that accommodate the separation of momentum flux measurements in two-phase blast flows.

Stevens, D E; Murphy, M J

2010-02-02T23:59:59.000Z

118

A programmable CCD driver circuit for multiphase CCD operation  

Science Conference Proceedings (OSTI)

A programmable CCD driver circuit was designed to drive CCD's in multiphased modes. The purpose of the drive electronics was to operate developmental CCD imaging arrays for NASA's Moderate Resolution Imaging Spectrometer - Tiltable (MODIS-T). Five prototype arrays were designed. Valid's Graphics Editor (GED) was used to design the driver. With this driver design, any of the five arrays can be readout. Designing the driver with GED allowed functional simulation, timing verification, and certain packaging analyses to be done on the design before fabrication. The driver verified its function with the master clock running up to 10 MHz. This suggests a maximum rate of 400 Kpixels/sec. Timing and packaging parameters were verified. the design uses 54 TTL component chips.

Ewin, A.J.; Reed, K.V.

1989-02-01T23:59:59.000Z

119

Scaling Relations for Turbulence in Multiphase Interstellar Medium  

E-Print Network (OSTI)

We simulate the dynamics of phase transition in radiatively cooling interstellar gas in three dimensions with a high order hydrodynamic method. We have previously shown (Kritsuk & Norman 2002a) in simulations with non-equilibrium initial conditions that thermal instability induces supersonic turbulence as a by-product of the phase transition which leads to formation of multiphase medium. We rely on a generalization of the She & Leveque (1994) model to study velocity scaling relations in this decaying turbulence and compare those with analogous results for compressible isothermal turbulence. Since radiative cooling promotes nonlinear instabilities in highly supersonic flows, turbulence in our simulations tends to be more intermittent than in the isothermal case. Hausdorff dimension of the most singular dissipative structures, D, can be as high as 2.3, while in supersonic isothermal turbulence D is limited by a more primitive nature of dissipation (shocks): D<=2. We also show that single-phase veloci...

Kritsuk, A G; Kritsuk, Alexei G.; Norman, Michael L.

2004-01-01T23:59:59.000Z

120

Multi-Phase Galaxy Formation and Quasar Absorption Systems  

E-Print Network (OSTI)

Abstract. The central problem of galaxy formation is understanding the cooling and condensation of gas in dark matter halos. It is now clear that to match observations this requires further physics than the simple assumptions of single phase gas cooling. A model of multi-phase cooling (Maller & Bullock 2004) can successfully account for the upper cutoff in the masses of galaxies and provides a natural explanation of many types of absorption systems (Mo & Miralda-Escude 1996). Absorption systems are our best probes of the gaseous content of galaxy halos and therefore provide important constraints on models for gas cooling into galaxies. All physical processes that effect gas cooling redistribute gas and therefore are detectable in absorption systems. Detailed studies of the nature of gas in galaxy halos using absorption systems are crucial for building a correct theory of galaxy formation.

P. R. Williams; C. Shu; B. Ménard; Ariyeh H. Maller

2005-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "multiphase reactive geochemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Multi-Phase Galaxy Formation and Quasar Absorption Systems  

E-Print Network (OSTI)

The central problem of galaxy formation is understanding the cooling and condensation of gas in dark matter halos. It is now clear that to match observations this requires further physics than the simple assumptions of single phase gas cooling. A model of multi-phase cooling (Maller & Bullock 2004) can successfully account for the upper cutoff in the masses of galaxies and provides a natural explanation of many types of absorption systems (Mo & Miralda-Escude 1996). Absorption systems are our best probes of the gaseous content of galaxy halos and therefore provide important constraints on models for gas cooling into galaxies. All physical processes that effect gas cooling redistribute gas and therefore are detectable in absorption systems. Detailed studies of the nature of gas in galaxy halos using absorption systems are crucial for building a correct theory of galaxy formation.

Ariyeh H. Maller

2005-05-06T23:59:59.000Z

122

Multi-Phase Galaxy Formation and Quasar Absorption Systems  

E-Print Network (OSTI)

The central problem of galaxy formation is understanding the cooling and condensation of gas in dark matter halos. It is now clear that to match observations this requires further physics than the simple assumptions of single phase gas cooling. A model of multi-phase cooling (Maller & Bullock 2004) can successfully account for the upper cutoff in the masses of galaxies and provides a natural explanation of many types of absorption systems (Mo & Miralda-Escude 1996). Absorption systems are our best probes of the gaseous content of galaxy halos and therefore provide important constraints on models for gas cooling into galaxies. All physical processes that effect gas cooling redistribute gas and therefore are detectable in absorption systems. Detailed studies of the nature of gas in galaxy halos using absorption systems are crucial for building a correct theory of galaxy formation.

Maller, A H

2005-01-01T23:59:59.000Z

123

Azo Dyes and Their Interfacial Activity: Implications for Multiphase Flow Experiments  

Science Conference Proceedings (OSTI)

Interfacial effects play an important role in governing multiphase fluid behavior in porous media (Neustadter 1984; Tuck et al. 1988). For instance, several dimensionless numbers have been developed to express important force ratios applicable to multiphase flow in porous media (Morrow and Songkran 1981; Chatzis and Morrow 1984; Wardlaw 1988; Pennell et al. 1996; Dawson and Roberts 1997). These force ratios emphasize the importance of interfacial properties. Our objectives are to provide chemical information regarding the dyes commonly used in multiphase flow visualization studies and to show the surface chemistry effects of the most commonly used dye, Sudan IV, in the tetrachloroethylene (PCE)-water-glass system

Tuck, D.M.

1999-04-21T23:59:59.000Z

124

Separator Design for Use in High GVF Multiphase Flow  

E-Print Network (OSTI)

The requirement of bringing an outside coolant source to run through the seals of a multiphase pump has always been a costly endeavor. Using a separator to extract liquid from the exhaust of the pump to use as a coolant is often more expensive than providing an outside source of coolant. This research proposes a cost effective separator design which efficiently separates the liquid from gas, while maintaining a high enough residence time to remove any gas entrainment, and separates only the seal flush requirement by letting any excess liquids carryover with the gas. Conventional multiphase separators operate by substantially decreasing the velocity of the mixture, which reduces the drag force put forth by the gasses and allows gravity to force the liquids downward. Gas-Liquid Cylindrical Cyclones (GLCCs) operate by increasing the velocity of the mixture, using radial force to separate liquids and gasses. This technique requires a smaller diameter vessel to achieve separation. The separator in this research uses gravity as the separation force while maintaining a pipe diameter similar to the GLCC. This way, only standard pipe and pipe fittings are used. The effectiveness of this design is measured two ways. First, efficiency is studied at varying gas volume fractions (GVFs), velocities, pressures, and pipe diameters. Second, the length of air entrainment (LAE) is measured at the same varying conditions. The efficiency and air entrainment studies provide design recommendations to accommodate seal flush requirements and size limitations. The following investigation also offers further areas of research to improve the understanding and modeling of using standard pipe and pipe fittings to create more effective design equations.

Cihak, Daniel

2012-08-01T23:59:59.000Z

125

Fluid Dynamic and Performance Behavior of Multiphase Progressive Cavity Pumps  

E-Print Network (OSTI)

It is common for an oil well to produce a mixture of hydrocarbons that flash when exposed to atmospheric pressure. The separation of oil and gas mixtures on site may prove expensive and lead to higher infrastructure and maintenance costs as well. A multiphase pump offers a good alternative with a lower capital cost and increased overall production. A Progressive Cavity Pump (PCP) is a positive displacement pump type that can be used to pump a wide range of multiphase mixtures, including high viscosity fluids with entrained gas and solid particles in suspension. Despite its advantages, a PCP has a reduced ability to handle high gas-liquid ratios due to limitations of its elastomeric stator material required to overcome thermo and mechanical effects. Also the efficiency decreases significantly with increases in gas volume fractions and reduced differential pressures. The current study focuses on studying the behavior of this unique pump in a wide range of GVFs and studying the effect of this ratio on overall efficiency, temperature and pressure distribution on the stator. The pump exhibits vibration issues at specific differential pressures and they have been studied in this work. This can be of critical value as severe vibration issues can damage the pump components such as couplings and bearings leading to high maintenance costs. Another important issue addressed by this research is the behavior of this pump in transient conditions. Oil well production is highly unpredictable with unexpected rises and drops in GVFs. These transient conditions have been simulated by varying the GVF over wide ranges and studying the pump's behavior in terms of load, temperature rises and instantaneous pressure profiles on the pump stator. This thesis provides a comprehensive study of this pump, its operating ranges and behavior in off-design conditions to assist oil and gas exploration ventures in making an informed choice in pump selection for their applications based on field conditions.

Narayanan, Shankar Bhaskaran

2011-08-01T23:59:59.000Z

126

An unstructured finite volume simulator for multiphase flow through fractured-porous media  

E-Print Network (OSTI)

Modeling of multiphase flow in fractured media plays an integral role in management and performance prediction of oil and gas reserves. Geological characterization and nmultiphase flow simulations in fractured media are ...

Bajaj, Reena

2009-01-01T23:59:59.000Z

127

Influence of Solid-Liquid-Liquid Interactions on Multiphase Transport Behavior in Porous Media  

Science Conference Proceedings (OSTI)

The flow of oil, water and gas in the complex network of paths in petroleum reservoir rocks constitutes probably the most complex embodiment of interfacial interactions and their consequences on multiphase transport behavior in porous media. The fact ...

Dandina N. Rao; Subhash C. Ayirala

2005-07-01T23:59:59.000Z

128

Lipid Oxidation PathwaysChapter 9 Protein Alterations Due to Lipid Oxidation in Multiphase Systems  

Science Conference Proceedings (OSTI)

Lipid Oxidation Pathways Chapter 9 Protein Alterations Due to Lipid Oxidation in Multiphase Systems Health Nutrition Biochemistry eChapters Health - Nutrition - Biochemistry Press Downloadable pdf of Chapter 9 P

129

Direct numerical simulations of multiphase flow with applications to basaltic volcanism and planetary evolution  

E-Print Network (OSTI)

Multiphase flows are an essential component of natural systems: They affect the explosivity of volcanic eruptions, shape the landscape of terrestrial planets, and govern subsurface flow in hydrocarbon reservoirs. Advancing ...

Suckale, Jenny

2011-01-01T23:59:59.000Z

130

Effects of buoyancy source composition on multiphase plume behavior in stratification  

E-Print Network (OSTI)

Experiments are performed where a dense multiphase plume is released vertically in a salinity stratified ambient. The constituent phase composition of the initial buoyancy flux can be dense brine, particles, or a mixture ...

Chow, Aaron C. (Aaron Chunghin), 1978-

2004-01-01T23:59:59.000Z

131

A high-resolution mapped grid algorithm for compressible multiphase flow problems  

Science Conference Proceedings (OSTI)

We describe a simple mapped-grid approach for the efficient numerical simulation of compressible multiphase flow in general multi-dimensional geometries. The algorithm uses a curvilinear coordinate formulation of the equations that is derived for the ... Keywords: 35L60, 58J45, 65M06, 65M50, 65Y15, Compressible multiphase flow, Fluid-mixture model, Mapped grids, Stiffened gas equation of state, Wave-propagation method

K. -M. Shyue

2010-11-01T23:59:59.000Z

132

An investigation of the effect of pore scale flow on average geochemical reaction rates using direct numerical simulation  

Science Conference Proceedings (OSTI)

The scale-dependence of geochemical reaction rates hinders their use in continuum scale models intended for the interpretation and prediction of chemical fate and transport in subsurface environments such as those considered for geologic sequestration of CO{sub 2}. Processes that take place at the pore scale, especially those involving mass transport limitations to reactive surfaces, may contribute to the discrepancy commonly observed between laboratory-determined and continuum-scale or field rates. Here, the dependence of mineral dissolution rates on the pore structure of the porous media is investigated by means of pore scale modeling of flow and multicomponent reactive transport. The pore scale model is comprised of high performance simulation tools and algorithms for incompressible flow and conservative transport combined with a general-purpose multicomponent geochemical reaction code. The model performs direct numerical simulation of reactive transport based on an operator-splitting approach to coupling transport and reactions. The approach is validated with a Poiseuille flow single-pore experiment and verified with an equivalent 1D continuum-scale model of a capillary tube packed with calcite spheres. Using the case of calcite dissolution as an example, the high resolution model is used to demonstrate that non-uniformity in the flow field at the pore scale has the effect of decreasing the overall reactivity of the system, even when systems with identical reactive surface area are considered. The effect becomes more pronounced as the heterogeneity of the reactive grain packing increases, particularly where the flow slows sufficiently such that the solution approaches equilibrium locally and the average rate becomes transport-limited.

Rafa, S. Molins; Trebotich, D.; Steefel, C. I.; Shen, C.

2012-02-01T23:59:59.000Z

133

System for reactivating catalysts  

DOE Patents (OSTI)

A method of reactivating a catalyst, such as a solid catalyst or a liquid catalyst is provided. The method comprises providing a catalyst that is at least partially deactivated by fouling agents. The catalyst is contacted with a fluid reactivating agent that is at or above a critical point of the fluid reactivating agent and is of sufficient density to dissolve impurities. The fluid reactivating agent reacts with at least one fouling agent, releasing the at least one fouling agent from the catalyst. The at least one fouling agent becomes dissolved in the fluid reactivating agent and is subsequently separated or removed from the fluid reactivating agent so that the fluid reactivating agent may be reused. A system for reactivating a catalyst is also disclosed.

Ginosar, Daniel M. (Idaho Falls, ID); Thompson, David N. (Idaho Falls, ID); Anderson, Raymond P. (Idaho Falls, ID)

2010-03-02T23:59:59.000Z

134

Design and Development of Integrated Compact Multiphase Separation System (CMSS)  

SciTech Connect

The petroleum industry has relied in the past mainly on conventional vessel-type separators, which are bulky, heavy and expensive, to process wellhead production of oil-water-gas flow. Economic and operational pressures continue to force the petroleum industry to seek less expensive and more efficient separation alternatives in the form of compact separators. The compact dimensions, smaller footprint and lower weight of compact separators have a potential for cost savings to the industry, especially in offshore and subsea applications. Also, compact separators reduce the inventory of hydrocarbons significantly, which is critical for environmental This report presents a brief overview of the activities and tasks accomplished during the Budget Period II (October 09, 2004-April 30, 2006) of the DOE project titled ''Design and Development of Integrated Compact Multiphase Separation System (CMSS{copyright})''. An executive summary is presented initially followed by the tasks of the current budget period. Then, detailed description of the experimental and modeling investigations are presented. Subsequently, the technical and scientific results of the activities of this project period are presented with discussions. The findings of this investigation are summarized in the ''Conclusions'' section In this investigation, the concept of CMSS{copyright} has been developed and is proven through simulation studies and validated by experimental data. As part of the second phase of the project (Budget Period II--10/09/2004-04/30/2006) experimental investigation of the integrated CMSS{copyright} for different configurations has been conducted in order to evaluate the performance of the individual separation components, and determine how they will affect the performance of each other when integrated in the CMSS{copyright}. An intelligent control system is also developed to improve the total system efficiency of Compact Multiphase Separation System (CMSS{copyright}). In mature oil fields, water handling poses a huge problem. Thus water knock out at the earliest stage helps in significant cost savings during handling, separation and transportation of oil. One of the objectives of the CMSS{copyright} configuration is to knock out free water from the upstream fluids. The results from theoretical and experimental studies show that Free Water Knock Out (FWKO) CMSS{copyright} system can be readily deployed in the field using the control system strategies designed, implemented and tested in this study.

Ram S. Mohan; Ovadia Shoham

2006-04-30T23:59:59.000Z

135

Thermal Conduction and Multiphase Gas in Cluster Cores  

E-Print Network (OSTI)

We examine the role of thermal conduction and magnetic fields in cores of galaxy clusters through global simulations of the intracluster medium (ICM). In particular, we study the influence of thermal conduction, both isotropic and anisotropic, on the condensation of multiphase gas in cluster cores. Previous hydrodynamic simulations have shown that cold gas condenses out of the hot ICM in thermal balance only when the ratio of the cooling time ($t_{\\rm cool}$) and the free-fall time ($t_{\\rm ff}$) is less than $\\approx 10$. Since thermal conduction is significant in the ICM and it suppresses local cooling at small scales, it is imperative to include thermal conduction in such studies. We find that anisotropic (along local magnetic field lines) thermal conduction does not influence the condensation criterion for a general magnetic geometry, even if thermal conductivity is large. However, with isotropic thermal conduction cold gas condenses only if conduction is suppressed (by a factor $\\lesssim 0.3$) with respe...

Wagh, Baban; McCourt, Michael

2013-01-01T23:59:59.000Z

136

Development, Verification, and Validation of Multiphase Models for Polydisperse Flows  

Science Conference Proceedings (OSTI)

This report describes in detail the technical findings of the DOE Award entitled 'Development, Verification, and Validation of Multiphase Models for Polydisperse Flows.' The focus was on high-velocity, gas-solid flows with a range of particle sizes. A complete mathematical model was developed based on first principles and incorporated into MFIX. The solid-phase description took two forms: the Kinetic Theory of Granular Flows (KTGF) and Discrete Quadrature Method of Moments (DQMOM). The gas-solid drag law for polydisperse flows was developed over a range of flow conditions using Discrete Numerical Simulations (DNS). These models were verified via examination of a range of limiting cases and comparison with Discrete Element Method (DEM) data. Validation took the form of comparison with both DEM and experimental data. Experiments were conducted in three separate circulating fluidized beds (CFB's), with emphasis on the riser section. Measurements included bulk quantities like pressure drop and elutriation, as well as axial and radial measurements of bubble characteristics, cluster characteristics, solids flux, and differential pressure drops (axial only). Monodisperse systems were compared to their binary and continuous particle size distribution (PSD) counterparts. The continuous distributions examined included Gaussian, lognormal, and NETL-provided data for a coal gasifier.

Christine Hrenya; Ray Cocco; Rodney Fox; Shankar Subramaniam; Sankaran Sundaresan

2011-12-31T23:59:59.000Z

137

DETERMINATION OF MECHANICAL AND HYDRAULIC BEHAVIOR OF TENSILE FRACTURES UNDER MULTIPHASE FLOW USING X-RAY COMPUTED TOMOGRAPHY.  

E-Print Network (OSTI)

??Understanding fracture morphology in terms of a porous media is necessary for accurate simulation of multiphase transport in fractured rocks. Although ambient-stress methods for obtaining… (more)

Alvarado, Freddy

2005-01-01T23:59:59.000Z

138

Numerical simulation of single-phase and multiphase non-Darcy flow in porous and fractured reservoirs  

E-Print Network (OSTI)

modeling fluid and heat flow in fractured porous media, Soc.flow of single-phase and multi-phase fluids in porous and fractured media.

Wu, Yu-Shu

2000-01-01T23:59:59.000Z

139

Using toughreact to model reactive fluid flow and geochemical transport in hydrothermal systems  

DOE Green Energy (OSTI)

The interaction between hydrothermal fluids and the rocks through which they migrate alters the earlier formed primary minerals and leads to the formation of secondary minerals, resulting in changes in the physical and chemical properties of the system. We have developed a comprehensive numerical simulator, TOUGHREACT, which considers nonisothermal multi-component chemical transport in both liquid and gas phases. A variety of subsurface thermo-physical-chemical processes is considered under a wide range of conditions of pressure, temperature, water saturation, and ionic strength. The code can be applied to problems in fundamental analysis of the hydrothermal systems and in the exploration of geothermal reservoirs including chemical evolution, mineral alteration, mineral scaling, changes of porosity and permeability, and mineral recovery from geothermal fluids.

Xu, Tianfu; Sonnenthal, Eric; Spycher, Nicolas; Pruess, Karsten

2003-07-31T23:59:59.000Z

140

Analysis and Geochemical Modeling of Vanadium Contamination in Groundwater New Rifle Processing Site, Colorado  

Energy.gov (U.S. Department of Energy (DOE))

Analysis and Geochemical Modeling of Vanadium Contamination in Groundwater New Rifle Processing Site, Colorado

Note: This page contains sample records for the topic "multiphase reactive geochemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Geochemical Sampling of Thermal Waters in Nevada | Open Energy Information  

Open Energy Info (EERE)

Geochemical Sampling of Thermal Waters in Nevada Geochemical Sampling of Thermal Waters in Nevada Jump to: navigation, search OpenEI Reference LibraryAdd to library Conference Paper: Geochemical Sampling of Thermal Waters in Nevada Abstract There are 1000 thermal springs in Nevada for which a location is known, but for which there are no available temperature (or chemical) measurements. Although many of these sites are within known geothermal areas and are located near springs for which temperature and/or geochemical data are available for one of the springs, many of these sites are not so located and require evaluation before the geothermal potential of the area can be assessed. In order to begin filling in data gaps, water sampling commenced in 2002 when over 70 analyses were obtained from springs with previously

142

Factors Controlling The Geochemical Evolution Of Fumarolic Encrustations,  

Open Energy Info (EERE)

Controlling The Geochemical Evolution Of Fumarolic Encrustations, Controlling The Geochemical Evolution Of Fumarolic Encrustations, Valley Of Ten Thousand Smokes, Alaska Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Factors Controlling The Geochemical Evolution Of Fumarolic Encrustations, Valley Of Ten Thousand Smokes, Alaska Details Activities (3) Areas (1) Regions (0) Abstract: Factor and canonical correlation analysis of geochemical data from eight fossil fumaroles suggest that six major factors controlled the formation and evolution of fumarolic encrustations on the 1912 ash-flow sheet in the Valley of Ten Thousand Smokes (VTTS). The six-factor solution model explains a large proportion (low of 74% for Ni to high of 99% for Si) of the individual element data variance. Although the primary fumarolic

143

Molecular geomicrobiology: genes and geochemical cycling Jennifer Macalady 1  

E-Print Network (OSTI)

Frontiers Molecular geomicrobiology: genes and geochemical cycling Jennifer Macalady 1 , Jillian F occurs. Yet, the field of molecular geomicrobiology remains in its infancy. In the foreseeable future, merging of modern biogeochemistry with molecularly resolved ecological studies will inspire

Macalady, Jenn

144

A Geochemical Reconnaissance Of The Alid Volcaniccenter And Geothermal  

Open Energy Info (EERE)

Geochemical Reconnaissance Of The Alid Volcaniccenter And Geothermal Geochemical Reconnaissance Of The Alid Volcaniccenter And Geothermal System, Danakil Depression, Eritrea Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Geochemical Reconnaissance Of The Alid Volcaniccenter And Geothermal System, Danakil Depression, Eritrea Details Activities (0) Areas (0) Regions (0) Abstract: Geological and geochemical studies indicate that a high-temperature geothermalsystem underlies the Alid volcanic center in the northern Danakil depression of Eritrea Alid is avery late-Pleistocene structural dome formed by shallow intrusion of rhyolitic magma some of which vented as lavas and pyroclastic flows Fumaroles and boiling pools distributed widelyover an area of ~10 km2 on the northern half of Alid suggest that an activehydrothermal system underlies much of that part of

145

Catalysis and Reactivity  

NLE Websites -- All DOE Office Websites (Extended Search)

understanding of basic principles of surface reactivity and its control by surface modification, on identification of active sites and full characterization of their electronic...

146

A validation process for multi-phase reacting flow CFD code  

DOE Green Energy (OSTI)

Computational fluid dynamic (CFD) code calculates flow properties for the analysis of a flow system. Flow properties are computed based on conservation principles and various phenomenological models. The accuracy of the computed flow properties highly depends on the validity of the models and the degree of numerical convergence. Validation of a CFD code is essential for application of an engineering system. Multiphase reacting flows are common in industrial applications and few CFD code are available. A CFD code was developed for the simulation of multiphase reacting flows. A validation process was also developed for such a CFD code. The validation was performed for several cases. Examples of industrial devices which are multiphase reacting flow systems include catalytic cracking reactors, glass melting furnaces, coal-fired combustors, and diesel engines.

Chang, S. L.; Zhou, C. Q.; Petrick, M.

2000-05-09T23:59:59.000Z

147

Experimental analysis of pressure distribution in a twin screw compressor for multiphase duties  

SciTech Connect

This paper presents the results of an experimental investigation of pressure distribution inside working chamber of a twin screw compressor for multiphase duties. A mathematical model for describing the pressure distribution inside working chamber is proposed. By means of a small pressure transducer embedded into the groove at the root of the rotor, the pressure distributions of a multiphase compressor under various running conditions have been recorded successfully to verify the model. It is found that the pressure curve during the discharge process has a higher level under the conditions of the lower gas void fraction, higher discharge pressure, higher rotational speed and higher inlet pressure. The pressure distribution calculated by model in this paper shows good agreement with the data recorded by a small pressure sensor in a prototype multiphase compressor at the high gas void fractions under different operating conditions. (author)

Cao, Feng; Gao, Tieyu; Li, Songshan; Xing, Ziwen; Shu, Pengcheng [School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049 (China)

2011-01-15T23:59:59.000Z

148

A ghost fluid, level set methodology for simulating multiphase electrohydrodynamic flows with application to liquid fuel injection  

Science Conference Proceedings (OSTI)

In this paper, we present the development of a sharp numerical scheme for multiphase electrohydrodynamic (EHD) flows for a high electric Reynolds number regime. The electric potential Poisson equation contains EHD interface boundary conditions, which ... Keywords: Conservative level set, DNS, Electrohydrodynamics, Ghost fluid method, Multiphase flow, Primary atomization

B. P. Van Poppel; O. Desjardins; J. W. Daily

2010-10-01T23:59:59.000Z

149

TOUGH+CO2: A multiphase fluid-flow simulator for CO2 geologic sequestration in saline aquifers  

Science Conference Proceedings (OSTI)

TOUGH+CO"2 is a new simulator for modeling of CO"2 geologic sequestration in saline aquifers. It is a member of TOUGH+, the successor to the TOUGH2 family of codes for multicomponent, multiphase fluid and heat flow simulation. The code accounts for heat ... Keywords: CO2 geologic sequestration, Modeling, Multiphase flow, Parallel computing, Saline aquifer, TOUGH+, TOUGH2

Keni Zhang; George Moridis; Karsten Pruess

2011-06-01T23:59:59.000Z

150

Three-dimensional model for multi-component reactive transport with variable density groundwater flow  

Science Conference Proceedings (OSTI)

PHWAT is a new model that couples a geochemical reaction model (PHREEQC-2) with a density-dependent groundwater flow and solute transport model (SEAWAT) using the split-operator approach. PHWAT was developed to simulate multi-component reactive transport ... Keywords: Cation exchange, Coastal groundwater flow and chemical transport/reaction, Density-dependent flow, MODFLOW, MT3DMS, PHREEQC-2, PHWAT, SEAWAT, Seawater intrusion, Snow-plough effect

X. Mao; H. Prommer; D. A. Barry; C. D. Langevin; B. Panteleit; L. Li

2006-05-01T23:59:59.000Z

151

Numerical simulation of air/water multiphase flows for ceramic sanitary ware design by multiple GPUs  

E-Print Network (OSTI)

8 Numerical simulation of air/water multiphase flows for ceramic sanitary ware design by multiple Compounds A Large-scale Simulation on CFD in Construction Industry Estimation of strong ground motion and manufacturing of plumbing products such as ceramic sanitary wares. In order to re-produce the complex

152

Dissipative Particle Dynamics Simulation of Pore-Scale Multiphase Fluid Flow  

Science Conference Proceedings (OSTI)

Multiphase fluid flow through porous media involves complex fluid dynamics, and it is difficult to model such complex behavior, on the pore scale, using grid-based continuum models. In this paper, the application of dissipative particle dynamics (DPD), a relatively new mesoscale method, to the simulation of pore-scale multiphase fluid flows under a variety of flow conditions is described. We demonstrate that the conventional DPD method using purely repulsive conservative (nondissipative) particle-particle interactions is capable of modeling single-phase flow fields in saturated porous media. In order to simulate unsaturated multiphase flow through porous media, we applied a modified model for the conservative particle-particle interactions that combines short-range repulsive and long-range attractive interactions. This form for the conservative particle-particle interactions allows the behavior of multiphase systems consisting of gases, liquids, and solids to be simulated. We also demonstrated that the flow of both wetting and nonwetting fluids through porous media can be simulated by controlling the ratios between the fluid-fluid and fluid-solid (fluid-wall) interparticle interaction strengths.

Paul Meakin; Hai Huang; Moubin Liu

2007-04-01T23:59:59.000Z

153

Adaptive multiscale finite-volume method for nonlinear multiphase transport in heterogeneous formations  

Science Conference Proceedings (OSTI)

In the previous multiscale finite-volume (MSFV) method, an efficient and accurate multiscale approach was proposed to solve the elliptic flow equation. The reconstructed fine-scale velocity field was then used to solve the nonlinear hyperbolic transport ... Keywords: Adaptivity, Multigrid, Multiphase flow, Multiscale finite-volume, Nonlinear transport, Porous media, Reservoir simulation

S. H. Lee; H. Zhou; H. A. Tchelepi

2009-12-01T23:59:59.000Z

154

Multiphase flow reconstruction in oil pipelines by capacitance tomography using simulated annealing  

E-Print Network (OSTI)

simulated annealing (SA) algorithm is applied to reconstruct permittivity images of real two-phase gas- oil such as mixing or stirring vessels, fluidized bed reactors, separator tanks and pipelines carrying multiphase in a cylindrical configuration close to the electrodes in order to improve resolution in the calculation

Martin, Roland

155

A Multiphase Traction/Fast-Battery-Charger Drive for Electric or Plug-in Hybrid Vehicles  

E-Print Network (OSTI)

A Multiphase Traction/Fast-Battery-Charger Drive for Electric or Plug-in Hybrid Vehicles Solutions and torque ripples. Keywords- Electric Vehicle, Plug-in Hybrid Vehicle, On-board Battery Charger, H on an original electric drive [1]-[3] dedicated to the vehicle traction and configurable as a battery charger

Paris-Sud XI, Université de

156

Spatial And Temporal Geochemical Trends In The Hydrothermal System Of  

Open Energy Info (EERE)

Spatial And Temporal Geochemical Trends In The Hydrothermal System Of Spatial And Temporal Geochemical Trends In The Hydrothermal System Of Yellowstone National Park- Inferences From River Solute Fluxes Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Spatial And Temporal Geochemical Trends In The Hydrothermal System Of Yellowstone National Park- Inferences From River Solute Fluxes Details Activities (2) Areas (1) Regions (0) Abstract: We present and analyze a chemical dataset that includes the concentrations and fluxes of HCO3-, SO42-, Cl-, and F- in the major rivers draining Yellowstone National Park (YNP) for the 2002-2004 water years (1 October 2001 - 30 September 2004). The total (molar) flux in all rivers decreases in the following order, HCO3- > Cl- > SO42- > F-, but each river is characterized by a distinct chemical composition, implying large-scale

157

Hg Anomalies In Soils- A Geochemical Exploration Method For Geothermal  

Open Energy Info (EERE)

Hg Anomalies In Soils- A Geochemical Exploration Method For Geothermal Hg Anomalies In Soils- A Geochemical Exploration Method For Geothermal Areas Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Hg Anomalies In Soils- A Geochemical Exploration Method For Geothermal Areas Details Activities (5) Areas (5) Regions (0) Abstract: Hg contents of soils in geothermal areas in the western U.S. were measured and a three-fold distribution was observed: peak, aureole and background. Peak values (up to several 100 ppm Hg) occur in fumaroles of vapour-dominated systems, around hot springs, and in zones overlying steeply dipping, hot-water aquifers. Aureoic values (up to several 100 ppb Hg) are found in zones surrounding the peak areas and delineate areas with shallow geothermal convection. Background values vary between 7 and 40 ppb

158

A Geochemical Model Of The Platanares Geothermal System, Honduras | Open  

Open Energy Info (EERE)

source source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit History Facebook icon Twitter icon » A Geochemical Model Of The Platanares Geothermal System, Honduras Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Geochemical Model Of The Platanares Geothermal System, Honduras Details Activities (0) Areas (0) Regions (0) Abstract: Results of exploration drilling combined with results of geologic, geophysical, and hydrogeochemical investigations have been used to construct a geochemical model of the Platanares geothermal system, Honduras. Three coreholes were drilled, two of which produced fluids from fractured Miocene andesite and altered Cretaceous to Eocene conglomerate at

159

Temporal Geochemical Variations In Volatile Emissions From Mount St Helens,  

Open Energy Info (EERE)

Temporal Geochemical Variations In Volatile Emissions From Mount St Helens, Temporal Geochemical Variations In Volatile Emissions From Mount St Helens, Usa, 1980-1994 Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Temporal Geochemical Variations In Volatile Emissions From Mount St Helens, Usa, 1980-1994 Details Activities (2) Areas (1) Regions (0) Abstract: Fumarole discharges (95-560°C) collected from the dacite dome inside Mount St. Helens crater show temporal changes in their isotopic and chemical compositions. A ΔD vs. Δ18O plot shows that condensed waters from the gases are mixtures of meteoric and magmatic components, but that the apparent magmatic end-member in 1994 was depleted by about 7‰ in ΔD relative to the apparent end-member in 1980. Based on ΔD modeling, approximately 63% of shallow, post-1980 magma has yet to degas.

160

Alteration And Geochemical Zoning In Bodie Bluff, Bodie Mining District,  

Open Energy Info (EERE)

Alteration And Geochemical Zoning In Bodie Bluff, Bodie Mining District, Alteration And Geochemical Zoning In Bodie Bluff, Bodie Mining District, Eastern California Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Alteration And Geochemical Zoning In Bodie Bluff, Bodie Mining District, Eastern California Details Activities (0) Areas (0) Regions (0) Abstract: Banded, epithermal quartz-adularia veins have produced about 1.5 million ounces of gold and 7 million ounces of silver from the Bodie mining district, eastern California. The veins cut dacitic lava flows, pyroclastic rocks and intrusions. Sinter boulders occur in a graben structure at the top of Bodie Bluff and fragments of sinter and mineralized quartz veins occur in hydrothermal breccias nearby. Explosive venting evidently was part of the evolution of the ore-forming geothermal systems which, at one time,

Note: This page contains sample records for the topic "multiphase reactive geochemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

A Reconnaissance Geochemical Study Of La Primavera Geothermal Area,  

Open Energy Info (EERE)

Reconnaissance Geochemical Study Of La Primavera Geothermal Area, Reconnaissance Geochemical Study Of La Primavera Geothermal Area, Jalisco, Mexico Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Reconnaissance Geochemical Study Of La Primavera Geothermal Area, Jalisco, Mexico Details Activities (0) Areas (0) Regions (0) Abstract: The Sierra La Primavera, a late Pleistocene rhyolitic caldera complex in Jalisco, Mexico, contains fumaroles and large-discharge 65°C hot springs that are associated with faults related to caldera collapse and to later magma insurgence. The nearly-neutral, sodium bicarbonate, hot springs occur at low elevations at the margins of the complex, whereas the water-rich fumaroles are high and central. The Comision Federal de Electricidad de Mexico (CFE) has recently drilled two deep holes at the

162

Surface tension of multi-phase flow with multiple junctions governed by the variational principle  

E-Print Network (OSTI)

We explore a computational model of an incompressible fluid with a multi-phase field in three-dimensional Euclidean space. By investigating an incompressible fluid with a two-phase field geometrically, we reformulate the expression of the surface tension for the two-phase field found by Lafaurie, Nardone, Scardovelli, Zaleski and Zanetti (J. Comp. Phys. \\vol{113} \\yr{1994} \\pages{134-147}) as a variational problem related to an infinite dimensional Lie group, the volume-preserving diffeomorphism. The variational principle to the action integral with the surface energy reproduces their Euler equation of the two-phase field with the surface tension. Since the surface energy of multiple interfaces even with singularities is not difficult to be evaluated in general and the variational formulation works for every action integral, the new formulation enables us to extend their expression to that of a multi-phase ($N$-phase, $N\\ge2$) flow and to obtain a novel Euler equation with the surface tension of the multi-phase field. The obtained Euler equation governs the equation of motion of the multi-phase field with different surface tension coefficients without any difficulties for the singularities at multiple junctions. In other words, we unify the theory of multi-phase fields which express low dimensional interface geometry and the theory of the incompressible fluid dynamics on the infinite dimensional geometry as a variational problem. We apply the equation to the contact angle problems at triple junctions. We computed the fluid dynamics for a two-phase field with a wall numerically and show the numerical computational results that for given surface tension coefficients, the contact angles are generated by the surface tension as results of balances of the kinematic energy and the surface energy.

Shigeki Matsutani; Kota Nakano; Katsuhiko Shinjo

2011-07-13T23:59:59.000Z

163

Reactive Transport and Coupled THM Processes in Engineering Barrier Systems (EBS)  

E-Print Network (OSTI)

of geological porous media with multiphase flow: Theory andmultiphase flow, solute transport andreactive chemistry in porousMultiphase Fluid Flow, Heat Transfer, and Deformation in Fractured Porous

Steefel, Carl

2010-01-01T23:59:59.000Z

164

Characterization of non-Darcy multiphase flow in petroleum bearing formations. Annual status report, May 14, 1991--May 13, 1992  

SciTech Connect

The objectives of this research are: Develop a proper theoretical model for characterizing non-Darcy multi-phase flow in petroleum bearing formations. Develop an experimental technique for measuring non-Darcy flow coefficients under multiphase flow at insitu reservoir conditions. Develop dimensional consistent correlations to express the non-Darcy flow coefficient as a function of rock and fluid properties for consolidated and unconsolidated porous media. The research accomplished during the period May 1991--May 1992 focused upon theoretical and experimental studies of multiphase non-Darcy flow in porous media.

Evans, R.D.; Civan, F.

1992-12-31T23:59:59.000Z

165

Characterization of non-Darcy multiphase flow in petroleum bearing formations. [Quarterly] report, January 1--March 30, 1993  

SciTech Connect

The objectives of this research are: Develop a proper theoretical model for characterizing non-Darcy multi-phase flow in petroleum bearing formations. Develop an experimental technique for measuring non-Darcy flow coefficients under multiphase flow at insitu reservoir conditions. Develop dimensional consistent correlations to express the non-Darcy flow coefficient as a function of rock and fluid properties for consolidated and unconsolidated porous media. The research accomplished during the period January 1993--March 1993 was focused upon theoretical and experimental studies to more accurately describe multiphase flow in porous media.

Evans, R.D.; Civan, F.

1993-12-31T23:59:59.000Z

166

Distribution and Geochemical Evolution of Fluoride in Groundwater of Taiyuan Basin, China  

Science Conference Proceedings (OSTI)

Hydrogeochemistry data were utilized to understand origin, distribution, and geochemical evolution of the high-fluoride groundwater in Taiyuan basin, China. In the study area, the spatial distribution of the high fluoride groundwater are strictly controlled ... Keywords: fluoride, geochemical mechanism

Xiangquan Li; Xinwei Hou; Zhichao Zhou; Lingxia Liu

2009-10-01T23:59:59.000Z

167

Crustal melting in the Himalayan orogen : field, geochemical and geochronological studies in the Everest region, Nepal  

E-Print Network (OSTI)

A combination of field studies and geochemical techniques were used to investigate the timing and processes involved in leucogranite generation in the Everest region of the Himalayan orogen. Geochemical investigations ...

Viskupic, Karen M. (Karen Marie), 1975-

2003-01-01T23:59:59.000Z

168

Reactive Power Compensator.  

DOE Patents (OSTI)

A system and method for determining and providing reactive power compensation for an inductive load. A reactive power compensator (50,50') monitors the voltage and current flowing through each of three distribution lines (52a, 52b, 52c), which are supplying three-phase power to one or more inductive loads. Using signals indicative of the current on each of these lines when the voltage waveform on the line crosses zero, the reactive power compensator determines a reactive power compensator capacitance that must be connected to the lines to maintain a desired VAR level, power factor, or line voltage. Alternatively, an operator can manually select a specific capacitance for connection to each line, or the capacitance can be selected based on a time schedule. The reactive power compensator produces control signals, which are coupled through optical fibers (102/106) to a switch driver (110, 110') to select specific compensation capacitors (112) for connections to each line. The switch driver develops triggering signals that are supplied to a plurality of series-connected solid state switches (350), which control charge current in one direction in respect to ground for each compensation capacitor. During each cycle, current flows from ground to charge the capacitors as the voltage on the line begins to go negative from its positive peak value. The triggering signals are applied to gate the solid state switches into a conducting state when the potential on the lines and on the capacitors reaches a negative peak value, thereby minimizing both the potential difference and across the charge current through the switches when they begin to conduct. Any harmonic distortion on the potential and current carried by the lines is filtered out from the current and potential signals used by the reactive power compensator so that it does not affect the determination of the required reactive compensation. 26 figs.

El-Sharkawi, M.A.; Venkata, S.S.; Chen, M.; Andexler, G.; Huang, T.

1992-07-28T23:59:59.000Z

169

Reactive power compensator  

DOE Patents (OSTI)

A system and method for determining and providing reactive power compensation for an inductive load. A reactive power compensator (50,50') monitors the voltage and current flowing through each of three distribution lines (52a, 52b, 52c), which are supplying three-phase power to one or more inductive loads. Using signals indicative of the current on each of these lines when the voltage waveform on the line crosses zero, the reactive power compensator determines a reactive power compensator capacitance that must be connected to the lines to maintain a desired VAR level, power factor, or line voltage. Alternatively, an operator can manually select a specific capacitance for connection to each line, or the capacitance can be selected based on a time schedule. The reactive power compensator produces control signals, which are coupled through optical fibers (102/106) to a switch driver (110, 110') to select specific compensation capacitors (112) for connections to each line. The switch driver develops triggering signals that are supplied to a plurality of series-connected solid state switches (350), which control charge current in one direction in respect to ground for each compensation capacitor. During each cycle, current flows from ground to charge the capacitors as the voltage on the line begins to go negative from its positive peak value. The triggering signals are applied to gate the solid state switches into a conducting state when the potential on the lines and on the capacitors reaches a negative peak value, thereby minimizing both the potential difference and across the charge current through the switches when they begin to conduct. Any harmonic distortion on the potential and current carried by the lines is filtered out from the current and potential signals used by the reactive power compensator so that it does not affect the determination of the required reactive compensation.

El-Sharkawi, Mohamed A. (Renton, WA); Venkata, Subrahmanyam S. (Woodinville, WA); Chen, Mingliang (Kirkland, WA); Andexler, George (Everett, WA); Huang, Tony (Seattle, WA)

1992-01-01T23:59:59.000Z

170

Merging High Resolution Geophysical and Geochemical Surveys to Reduce  

Open Energy Info (EERE)

Merging High Resolution Geophysical and Geochemical Surveys to Reduce Merging High Resolution Geophysical and Geochemical Surveys to Reduce Exploration Risk at Glass Buttes, Oregon Geothermal Project Jump to: navigation, search Last modified on July 22, 2011. Project Title Merging High Resolution Geophysical and Geochemical Surveys to Reduce Exploration Risk at Glass Buttes, Oregon Project Type / Topic 1 Recovery Act: Geothermal Technologies Program Project Type / Topic 2 Validation of Innovative Exploration Technologies Project Description This program will combine detailed gravity, high resolution aeromagnetic, and LIDAR data, all of which will be combined for structural modeling, with hyperspectral data, which will identify and map specific minerals and mineral assemblages that may point to upflow zones. The collection of these surveys and analyses of the merged data and model will be used to site deeper slim holes. Slim holes will be flow tested to determine whether or not Ormat can move forward with developing this resource. An innovative combination of geophysical and geochemical tools will significantly reduce risk in exploring this area, and the results will help to evaluate the value of these tools independently and in combination when exploring for blind resources where structure, permeability, and temperature are the most pressing questions. The slim holes will allow testing of models and validation of methods, and the surveys within the wellbores will be used to revise the models and site production wells if their drilling is warranted.

171

Synthesis of organic geochemical data from the Eastern Gas Shales  

Science Conference Proceedings (OSTI)

Over 2400 core and cuttings samples of Upper Devonian shales from wells in the Appalachian, Illinois, and Michigan Basins have been characterized by organic geochemical methods to provide a basis for accelerating the exploitation of this unconventional, gas-rich resource. This work was part of a program initiated to provide industry with criteria for locating the best areas for future drilling and for the development of stimulation methods that will make recovery of the resource economically attractive. The geochemical assessment shows that the shale, in much of the Appalachian, Illinois, and Michigan Basins is source rock that is capable of generating enormous quantities of gas. In some areas the shales are also capable of generating large quantities of oil as well. The limiting factors preventing these sources from realizing most of their potential are their very low permeabilities and the paucity of potential reservoir rocks. This geochemical data synthesis gives direction to future selection of sites for stimulation research projects in the Appalachian Basin by pinpointing those areas where the greatest volumes of gas are contained in the shale matrix. Another accomplishment of the geochemical data synthesis is a new estimate of the total resource of the Appalachian Basin. The new estimate of 2500 TCF is 25 percent greater than the highest previous estimates. This gives greater incentive to government and industry to continue the search for improved stimulation methods, as well as for improved methods for locating the sites where those improved stimulation methods can be most effectively applied.

Zielinski, R. E.; McIver, R. D.

1982-01-01T23:59:59.000Z

172

Modeling twin-screw multiphase pump performance during periods of high gas volume fraction  

E-Print Network (OSTI)

Multiphase pumping is a new technology used for reducing capital investments, increasing production rates, and improving recoveries in many on-shore projects. Interest is also growing in the subsea/offshore application of this technology. Multiphase pumping adds energy to an unprocessed effluent stream acting as a combined pump and compressor, permitting the recovery of oil and gas on an economical basis. In practice, multiphase production is characterized by wide fluctuations in the gas and liquid mass flow rates. During periods of substantial gas flow, temperature becomes the critical variable determining the performance of the pump. Without the liquid phase to remove the gas compression heat, temperatures in the discharge gas stream begin to rise causing a decrease in efficiency, a high temperature shut-in of the pump, and damage to the pump. While this behavior has been observed in lab experiments and in the field, a review of literature reveals that no mechanistic model exists for predicting the performance of a twin-screw pump under high gas volume flow conditions. Also, very few data are available under high GVF conditions. Both large-scale experiments and mechanistic modeling were performed as part of this research. This thesis models the behavior of a twin-screw multiphase pump under high gas volume fraction conditions. The model of the pump is based on fundamental principles of thermodynamic and fluid mechanics. The specific experimental tasks undertaken in this work include studying the volumetric pump performance during periods of high gas volume fractions, the observation of temperature increase with time under periods of 100% gas volume fraction and studying the effect of viscosity on high GVF performance. The results indicate that the pump can be operated during periods of 100% gas volume fractions. The volumetric efficiency of the twin-screw multiphase pump during periods of high to 100% gas volume fractions can be improved by increasing the viscosity of the process stream or by injecting high viscosity fluids into the pump casing. At 94-95% gas volume fraction the system transitions from isothermal conditions. And the system moves from isothermal to adiabatic (uncooled) conditions with time. A model has been generated that predicts temperature increase with time as a function of the key parameters of pump speed, differential pressure, mass flow rate, specific heat and slip flow. This model can be used to develop novel control philosophies for operating multiphase pumps during high gas volume fractions.

Singh, Aditya

2003-01-01T23:59:59.000Z

173

Methods, systems and apparatus for approximation of peak summed fundamental and third harmonic voltages in a multi-phase machine  

DOE Patents (OSTI)

Methods, system and apparatus are provided for quickly approximating a peak summed magnitude (A) of a phase voltage (Vph) waveform in a multi-phase system that implements third harmonic injection.

Ransom, Ray M. (Big Bear City, CA); Gallegos-Lopez, Gabriel (Torrance, CA); Kinoshita, Michael H. (Redondo Beach, CA)

2012-07-31T23:59:59.000Z

174

The Influence of Proposed Repository Thermal Load on Multiphase Flow and Heat Transfer in the Unsaturated Zone of Yucca Mountain  

E-Print Network (OSTI)

22]. Fluid flow and heat-transfer processes in a two-phase,processes associated with multiphase flow and heat transferprocesses has also motivated development of fluid flow and heat transfer

Wu, Y.-S.; Mukhopadhyay, Sumit; Zhang, Keni; Bodvarsson, G.S.

2006-01-01T23:59:59.000Z

175

Validation of the WATEQ4 geochemical model for uranium  

SciTech Connect

As part of the Geochemical Modeling and Nuclide/Rock/Groundwater Interactions Studies Program, a study was conducted to partially validate the WATEQ4 aqueous speciation-solubility geochemical model for uranium. The solubility controls determined with the WATEQ4 geochemical model were in excellent agreement with those laboratory studies in which the solids schoepite (UO/sub 2/(OH)/sub 2/ . H/sub 2/O), UO/sub 2/(OH)/sub 2/, and rutherfordine ((UO/sub 2/CO/sub 3/) were identified as actual solubility controls for uranium. The results of modeling solution analyses from laboratory studies of uranyl phosphate solids, however, identified possible errors in the characterization of solids in the original solubility experiments. As part of this study, significant deficiencies in the WATEQ4 thermodynamic data base for uranium solutes and solids were corrected. Revisions included recalculation of selected uranium reactions. Additionally, thermodynamic data for the hydroxyl complexes of U(VI), including anionic (VI) species, were evaluated (to the extent permitted by the available data). Vanadium reactions were also added to the thermodynamic data base because uranium-vanadium solids can exist in natural ground-water systems. This study is only a partial validation of the WATEQ4 geochemical model because the available laboratory solubility studies do not cover the range of solid phases, alkaline pH values, and concentrations of inorganic complexing ligands needed to evaluate the potential solubility of uranium in ground waters associated with various proposed nuclear waste repositories. Further validation of this or other geochemical models for uranium will require careful determinations of uraninite solubility over the pH range of 7 to 10 under highly reducing conditions and of uranyl hydroxide and phosphate solubilities over the pH range of 7 to 10 under oxygenated conditions.

Krupka, K.M.; Jenne, E.A.; Deutsch, W.J.

1983-09-01T23:59:59.000Z

176

Oxyferryl Heme Reactivity  

NLE Websites -- All DOE Office Websites (Extended Search)

Oxyferryl Heme Reactivity Using both Radiation and Photochemical Oxyferryl Heme Reactivity Using both Radiation and Photochemical Techniques A. M. English, T. Fox, G. Tsaprailis, C. W. Fenwick, J. F. Wishart, J. T. Hazzard, and G. Tollin Adv. Chem. Ser. 254, Ch. 6, pp. 81-98 Abstract: Flash photolysis and pulse radiolysis were used to generate reductants in situ to study the electron-transfer (ET) reactivity of the FeIV=O heme centers in myoglobin and cytochrome c peroxidase. Reduction of a5RuIII groups covalently bound to surface histidines allowed intramolecular RuII --> FeIV=O ET rates to be measured. Protonation of the oxene ligand was found to be largely rate determining in myoglobin, consistent with the lack of proton donors in its heme pocket. The large distance (21-23 Ă…) between surface histidines and the heme in wild-type

177

Reactivity of Acid Generators  

NLE Websites -- All DOE Office Websites (Extended Search)

Reactivity of Acid Generators for Chemically Amplified Resists with Reactivity of Acid Generators for Chemically Amplified Resists with Low-Energy Electrons Atsuro Nakano, Takahiro Kozawa, Seiichi Tagawa, Tomasz Szreder, James F. Wishart, Toshiyuki Kai and Tsutomu Shimokawa Jpn. J. Appl. Phys., 45, L197-L200 (2006). [Find paper at the Japanese Journal of Applied Physics] Abstract: In chemically amplified resists for ionizing radiations such as electron beams and extreme ultraviolet (EUV), low-energy electrons play an important role in the pattern formation processes. The reactivity of acid generators with low-energy electrons was evaluated using solvated electrons in tetrahydrofuran, which were generated by a pulsed electron beam. The rate constants of acid generators with the solvated electrons ranged from 0.6 to 1.9 x 1011 M-1s-1

178

Lattice Boltzmann Method for Multiphase Flows with High Density and Viscosity Ratios  

NLE Websites -- All DOE Office Websites (Extended Search)

Lattice Boltzmann Method for Multiphase Flows with High Density and Viscosity Ratios Lattice Boltzmann Method for Multiphase Flows with High Density and Viscosity Ratios Seckin Gokaltun, Dwayne McDaniel and David Roelant Florida International University, Miami, FL Background As a result of atomic weapons production, millions of gallons of radioactive waste was generated and stored in underground tanks at various U.S. Department of Energy sites. Department of Energy is currently in the process of transferring the waste from single shell tanks to double shell tanks. Various waste retrieval and processing methods are employed during the transfer of the waste. One such method, pulsed-air mixing, involves injection of discrete pulses of compressed air or inert gas at the bottom of the tank to produce large bubbles that rise due to buoyancy and mix the waste in the tank

179

High-Fidelity Multi-Phase Radiation Module for Modern Coal Combustion Systems  

NLE Websites -- All DOE Office Websites (Extended Search)

Task Task Description Sample calculations LBL-PMC Future Work High-Fidelity Multi-Phase Radiation Module for Modern Coal Combustion Systems Jian Cai 1 Ricardo Marquez 1 Michael F. Modest 2 1 Postdoctoral Research Associate 2 Shaffer and George Professor of Engineering University of California Merced Merced, CA 95343, USA DE-FG26-10FE0003801 May 2012 - Pittsburgh 2/17 Introduction Task Description Sample calculations LBL-PMC Future Work Radiation Challenges in Multi-Phase Reacting Flows Radiative heat transfer in high temperature combustion systems Thermal radiation becomes very important at elevated temperatures Coal and hydrocarbon fuels C n H m → H 2 O, CO 2 , CO, NO x , soot, char, ash CO 2 , H 2 O, soot, char and ash strongly emit and absorb radiative energy (lower temperature levels) Radiative effects are conveniently ignored or treated with very crude models Neglecting

180

Stochastic Finite Element Analysis for Multiphase Flow in Heterogeneous Porous Media  

E-Print Network (OSTI)

. This study is concerned with developing a two-dimensional multiphase model that simulates the movement of NAPL in heterogeneous aquifers. Heterogeneity is dealt with in a probabilistic sense by modeling the intrinsic permeability of the porous medium as a stochastic process. The deterministic finite element method is used to spatially discretize the multiphase flow equations. The intrinsic permeability is represented in the model via its Karhunen-Loeve expansion (Ghanem and Spanos, 1991). This is a computationally expedient representation of stochastic processes by means of a discrete set of random variables. Further, the nodal unknowns, water phase saturations and water phase pressures, are represented by their stochastic spectral expansions. This representation involves an orthogonal basis in the space of random variables. The basis consists of orthogonal polynomial chaoses of consecutive orders. The relative permeabilities of water and oil phases, and the capillary pressure are ex...

R. Ghanem; S. Dham

1998-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "multiphase reactive geochemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

LDRD final report: Physical simulation of nonisothermal multiphase multicomponent flow in porous media  

Science Conference Proceedings (OSTI)

This document reports on the accomplishments of a laboratory-directed research and development (LDRD) project whose objective was to initiate a research program for developing a fundamental understanding of multiphase multicomponent subsurface transport in heterogeneous porous media and to develop parallel processing computational tools for numerical simulation of such problems. The main achievement of this project was the successful development of a general-purpose, unstructured grid, multiphase thermal simulator for subsurface transport in heterogeneous porous media implemented for use on massively parallel (MP) computers via message-passing and domain decomposition techniques. The numerical platform provides an excellent base for new and continuing project development in areas of current interest to SNL and the DOE complex including, subsurface nuclear waste disposal and cleanup, groundwater availability and contamination studies, fuel-spill transport for accident analysis, and DNAPL transport and remediation.

Martinez, M.J.; Hopkins, P.L.; Shadid, J.N.

1997-07-01T23:59:59.000Z

182

Laboratory setup and results of experiments on two-dimensional multiphase flow in porous media  

Science Conference Proceedings (OSTI)

In the event of an accidental release into earth's subsurface of an immiscible organic liquid, such as a petroleum hydrocarbon or chlorinated organic solvent, the spatial and temporal distribution of the organic liquid is of great interest when considering efforts to prevent groundwater contamination or restore contaminated groundwater. An accurate prediction of immiscible organic liquid migration requires the incorporation of relevant physical principles in models of multiphase flow in porous media; these physical principles must be determined from physical experiments. This report presents a series of such experiments performed during the 1970s at the Swiss Federal Institute of Technology (ETH) in Zurich, Switzerland. The experiments were designed to study the transient, two-dimensional displacement of three immiscible fluids in a porous medium. This experimental study appears to be the most detailed published to date. The data obtained from these experiments are suitable for the validation and test calibration of multiphase flow codes. 73 refs., 140 figs.

McBride, J.F. (ed.) (Pacific Northwest Lab., Richland, WA (USA)); Graham, D.N. (ed.); Schiegg, H.O. (SIMULTEC Ltd., Meilen/Zurich (Switzerland))

1990-10-01T23:59:59.000Z

183

Considerations for developing models of multiphase flow in deformable porous media.  

Science Conference Proceedings (OSTI)

This document summarizes research and planning for the development of a numerical simulation capability for nonisothermal multiphase, multicomponent transport in heterogeneous deformable porous materials. Particular attention is given to describing a mathematical formulation for flow in deformable media and for numerical techniques for dealing with phase transitions. A development plan is formulated to provide a computational capability motivated by current and future needs in geosystems management for energy security.

Martinez, Mario J.; Stone, Charles Michael

2008-09-01T23:59:59.000Z

184

Local volume-time averaged equations of motion for dispersed, turbulent, multiphase flows  

Science Conference Proceedings (OSTI)

In most flows of liquids and their vapors, the phases are dispersed randomly in both space and time. These dispersed flows can be described only statistically or in terms of averages. Local volume-time averaging is used here to derive a self-consistent set of equations governing momentum and energy transfer in dispersed, turbulent, multiphase flows. The empiricisms required for use with these equations are the subject of current research.

Sha, W.T.; Slattery, J.C.

1980-11-01T23:59:59.000Z

185

Reactive Power Compensating System.  

DOE Patents (OSTI)

The circuit was designed for the specific application of wind-driven induction generators. It has great potential for application in any situation where a varying reactive power load is present, such as with induction motors or generators, or for transmission network compensation.

Williams, Timothy J.; El-Sharkawi, Mohamed A.; Venkata, Subrahmanyam S.

1985-01-04T23:59:59.000Z

186

Reactive power compensating system  

DOE Patents (OSTI)

The reactive power of an induction machine is compensated by providing fixed capacitors on each phase line for the minimum compensation required, sensing the current on one line at the time its voltage crosses zero to determine the actual compensation required for each phase, and selecting switched capacitors on each line to provide the balance of the compensation required.

Williams, Timothy J. (Redondo Beach, CA); El-Sharkawi, Mohamed A. (Renton, WA); Venkata, Subrahmanyam S. (Seattle, WA)

1987-01-01T23:59:59.000Z

187

Geochemical characterization of geothermal systems in the Great Basin:  

Open Energy Info (EERE)

characterization of geothermal systems in the Great Basin: characterization of geothermal systems in the Great Basin: Implications for exploration, exploitation, and environmental issues Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Paper: Geochemical characterization of geothermal systems in the Great Basin: Implications for exploration, exploitation, and environmental issues Details Activities (0) Areas (0) Regions (0) Abstract: The objective of this ongoing project is the development of a representative geochemical database for a comprehensive range of elemental and isotopic parameters (i.e., beyond the typical data suite) for a range of geothermal systems in the Great Basin. Development of this database is one of the first steps in understanding the nature of geothermal systems in the Great Basin. Of particular importance in the Great Basin is utilizing

188

Lectures on geochemical interpretation of hydrothermal waters | Open Energy  

Open Energy Info (EERE)

form form View source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit with form History Facebook icon Twitter icon » Lectures on geochemical interpretation of hydrothermal waters Jump to: navigation, search OpenEI Reference LibraryAdd to library Report: Lectures on geochemical interpretation of hydrothermal waters Abstract The alkali carbonates, Na, K, and Li, are relatively soluble at all temperatures and generally precipitate only where there is extreme evapora- tion. In contrast, the alkaline earth carbonates. Ca. Ht, Sr, and Ba, are moderately to sparingly soluble and commonly precipitate in bydrothecmal systems. Calcite is by far the most abundant and important carbonate found

189

Geochemical modeling of the Raft River geothermal field | Open Energy  

Open Energy Info (EERE)

Page Page Edit History Facebook icon Twitter icon » Geochemical modeling of the Raft River geothermal field Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Report: Geochemical modeling of the Raft River geothermal field Details Activities (1) Areas (1) Regions (0) Abstract: The results to date of chemical modeling of the Raft River KGRA are presented. Earlier work indicated a northwest-southeast anomaly in the contours. Modeling techniques applied to more complete data allowed further definition of the anomaly. Models described in this report show the source of various minerals in the geothermal water. There appears to be a regional heat source that gives rise to uniform conductive heat flow in the region, but convective flow is concentrated near the upwelling in the Crook well

190

Version 4.00 of the MINTEQ geochemical code  

DOE Green Energy (OSTI)

The MINTEQ code is a thermodynamic model that can be used to calculate solution equilibria for geochemical applications. Included in the MINTEQ code are formulations for ionic speciation, ion exchange, adsorption, solubility, redox, gas-phase equilibria, and the dissolution of finite amounts of specified solids. Since the initial development of the MINTEQ geochemical code, a number of undocumented versions of the source code and data files have come into use at the Pacific Northwest Laboratory (PNL). This report documents these changes, describes source code modifications made for the Aquifer Thermal Energy Storage (ATES) program, and provides comprehensive listings of the data files. A version number of 4.00 has been assigned to the MINTEQ source code and the individual data files described in this report.

Eary, L.E.; Jenne, E.A.

1992-09-01T23:59:59.000Z

191

Version 4. 00 of the MINTEQ geochemical code  

DOE Green Energy (OSTI)

The MINTEQ code is a thermodynamic model that can be used to calculate solution equilibria for geochemical applications. Included in the MINTEQ code are formulations for ionic speciation, ion exchange, adsorption, solubility, redox, gas-phase equilibria, and the dissolution of finite amounts of specified solids. Since the initial development of the MINTEQ geochemical code, a number of undocumented versions of the source code and data files have come into use at the Pacific Northwest Laboratory (PNL). This report documents these changes, describes source code modifications made for the Aquifer Thermal Energy Storage (ATES) program, and provides comprehensive listings of the data files. A version number of 4.00 has been assigned to the MINTEQ source code and the individual data files described in this report.

Eary, L.E.; Jenne, E.A.

1992-09-01T23:59:59.000Z

192

Fluid-rock interaction: A reactive transport approach  

SciTech Connect

Fluid-rock interaction (or water-rock interaction, as it was more commonly known) is a subject that has evolved considerably in its scope over the years. Initially its focus was primarily on interactions between subsurface fluids of various temperatures and mostly crystalline rocks, but the scope has broadened now to include fluid interaction with all forms of subsurface materials, whether they are unconsolidated or crystalline ('fluid-solid interaction' is perhaps less euphonious). Disciplines that previously carried their own distinct names, for example, basin diagenesis, early diagenesis, metamorphic petrology, reactive contaminant transport, chemical weathering, are now considered to fall under the broader rubric of fluid-rock interaction, although certainly some of the key research questions differ depending on the environment considered. Beyond the broadening of the environments considered in the study of fluid-rock interaction, the discipline has evolved in perhaps an even more important way. The study of water-rock interaction began by focusing on geochemical interactions in the absence of transport processes, although a few notable exceptions exist (Thompson 1959; Weare et al. 1976). Moreover, these analyses began by adopting a primarily thermodynamic approach, with the implicit or explicit assumption of equilibrium between the fluid and rock. As a result, these early models were fundamentally static rather than dynamic in nature. This all changed with the seminal papers by Helgeson and his co-workers (Helgeson 1968; Helgeson et al. 1969) wherein the concept of an irreversible reaction path was formally introduced into the geochemical literature. In addition to treating the reaction network as a dynamically evolving system, the Helgeson studies introduced an approach that allowed for the consideration of a multicomponent geochemical system, with multiple minerals and species appearing as both reactants and products, at least one of which could be irreversible. Helgeson's pioneering approach was given a more formal kinetic basis (including the introduction of real time rather than reaction progress as the independent variable) in subsequent studies (Lasaga 1981; Aagaard and Helgeson 1982; Lasaga 1984). The reaction path approach can be used to describe chemical processes in a batch or closed system (e.g., a laboratory beaker), but such systems are of limited interest in the Earth sciences where the driving force for most reactions is transport. Lichtner (1988) clarified the application of the reaction path models to water-rock interaction involving transport by demonstrating that they could be used to describe pure advective transport through porous media. By adopting a reference frame which followed the fluid packet as it moved through the medium, the reaction progress variable could be thought of as travel time instead. Multi-component reactive transport models that could treat any combination of transport and biogeochemical processes date back to the early 1980s. Berner and his students applied continuum reactive transport models to describe processes taking place during the early diagenesis of marine sediments (Berner 1980). Lichtner (1985) outlined much of the basic theory for a continuum model for multicomponent reactive transport. Yeh and Tripathi (1989) also presented the theoretical and numerical basis for the treatment of reactive contaminant transport. Steefel and Lasaga (1994) presented a reactive flow and transport model for nonisothermal, kinetically-controlled water-rock interaction and fracture sealing in hydrothermal systems based on simultaneous numerical solution of both reaction and transport This chapter begins with a review of the important transport processes that affect or even control fluid-rock interaction. This is followed by a general introduction to the governing equations for reactive transport, which are broadly applicable to both qualitative and quantitative interpretations of fluid-rock interactions. This framework is expanded through a discussion of specific topics that are the f

Steefel, C.; Maher, K.

2009-04-01T23:59:59.000Z

193

Geochemical engineering design tools for uranium in situ recovery : the HYDROGEOCHEM codes.  

SciTech Connect

Geochemical Engineering Design (GED) is based on applications of the principles and various computer models that describe the biogeochemistry and physics of removal of contaminants from water by adsorption, precipitation and filtration. It can be used to optimize or evaluate the efficiency of all phases of in situ recovery (ISR). The primary tools of GED are reactive transport models; this talk describes the potential application of the HYDROGEOCHEM family of codes to ISR. The codes can describe a complete suite of equilibrium or kinetic aqueous complexation, adsorption-desorption, precipitation-dissolution, redox, and acid-base reactions in variably saturated media with density-dependent fluid flow. Applications to ISR are illustrated with simulations of (1) the effectiveness of a reactive barrier to prevent off-site uranium migration and (2) evaluation of the effect of sorption hysteresis on natural attenuation. In the first example, it can be seen that the apparent effectiveness of the barrier depends on monitoring location and that it changes over time. This is due to changes in pH, saturation of sorption sites, as well as the geometry of the flow field. The second simulation shows how sorption hysteresis leads to observable attenuation of a uranium contamination plume. Different sorption mechanisms including fast (or reversible), slow, and irreversible sorption were simulated. The migration of the dissolved and total uranium plumes for the different cases are compared and the simulations show that when 50-100% of the sites have slow desorption rates, the center of mass of the dissolved uranium plume begins to move upstream. This would correspond to the case in which the plume boundaries begin to shrink as required for demonstration of natural attenuation.

Siegel, Malcolm Dean; Li, Ming-Hsu (National Central University, Jhongli City, Taiwan); Yeh, Gour-Tsyh (University of Central Florida, Orlando, FL)

2010-11-01T23:59:59.000Z

194

Investigating capillary pressure and interfacial area for multiphase flow in porous media using pore-scale imaging and lattice-Boltzmann modeling.  

E-Print Network (OSTI)

??Recent advances in imaging technology and numerical modeling have greatly enhanced pore-scale investigations of multiphase flow and transport in porous media. It is now feasible… (more)

[No author

2008-01-01T23:59:59.000Z

195

Grid Shunt Reactive Power Compensation  

Science Conference Proceedings (OSTI)

This report provides essential information on transmission grid shunt reactive power compensation, with particular focus on controllable reactive power sources such as the static var controller (SVC). Applying the information presented in this report can help electric utilities planning grid shunt reactive power compensation strategies or operating shunt reactive power compensation equipment to increase grid reliability, improve grid performance and prevent costly cascading outages. The report is intende...

2008-11-26T23:59:59.000Z

196

Reactive Air Aluminization  

DOE Green Energy (OSTI)

Ferritic stainless steels and other alloys are of great interest to SOFC developers for applications such as interconnects, cell frames, and balance of plant components. While these alloys offer significant advantages (e.g., low material and manufacturing cost, high thermal conductivity, and high temperature oxidation resistance), there are challenges which can hinder their utilization in SOFC systems; these challenges include Cr volatility and reactivity with glass seals. To overcome these challenges, protective coatings and surface treatments for the alloys are under development. In particular, aluminization of alloy surfaces offers the potential for mitigating both evaporation of Cr from the alloy surface and reaction of alloy constituents with glass seals. Commercial aluminization processes are available to SOFC developers, but they tend to be costly due to their use of exotic raw materials and/or processing conditions. As an alternative, PNNL has developed Reactive Air Aluminization (RAA), which offers a low-cost, simpler alternative to conventional aluminization methods.

Choi, Jung-Pyung; Chou, Y. S.; Stevenson, Jeffry W.

2011-10-28T23:59:59.000Z

197

Reactive Maintenance | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Reactive Maintenance Reactive Maintenance Reactive Maintenance October 7, 2013 - 9:40am Addthis Reactive maintenance follows a run-it-until-it-breaks strategy where no actions or efforts are taken to maintain equipment as intended by the manufacturer. Studies indicate this is still the predominant mode of maintenance for Federal facilities. Advantages Reactive maintenance advantages are a double-edged sword. Federal agencies following a purely reactive maintenance strategy can expect little expenditures for manpower or system upkeep until something breaks. However, systems do break. With new equipment, Federal agencies can expect minimal incidents of failure. However, older equipment often experiences higher failure incidents and costlier repairs. Other advantages of reactive maintenance are:

198

A geochemical model of the Kilauea east rift zone | Open Energy Information  

Open Energy Info (EERE)

A geochemical model of the Kilauea east rift zone A geochemical model of the Kilauea east rift zone Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: A geochemical model of the Kilauea east rift zone Abstract N/A Author Donald Thomas Published Journal US Geological Survey Professional Paper 1350, 1987 DOI Not Provided Check for DOI availability: http://crossref.org Online Internet link for A geochemical model of the Kilauea east rift zone Citation Donald Thomas. 1987. A geochemical model of the Kilauea east rift zone. US Geological Survey Professional Paper 1350. (!) . Retrieved from "http://en.openei.org/w/index.php?title=A_geochemical_model_of_the_Kilauea_east_rift_zone&oldid=682589" Categories: Missing Required Information References Uncited References Geothermal References

199

Toward a General Theory for Multiphase Turbulence Part I: Development and Gauging of the Model Equations  

SciTech Connect

A formalism for developing multiphase turbulence models is introduced by analogy to the phenomenological method used for single-phase turbulence. A sample model developed using the formalism is given in detail. The procedure begins with ensemble averaging of the exact conservation equations, with closure accomplished by using a combination of analytical and experimental results from the literature. The resulting model is applicable to a wide range of common multiphase flows including gas-solid, liquid-solid and gas-liquid (bubbly) flows. The model is positioned for ready extension to three-phase turbulence, or for use in two-phase turbulence in which one phase is accounted for in multiple size classes, representing polydispersivity. The formalism is expected to suggest directions toward a more fundamentally based theory, similar to the way that early work in single-phase turbulence has led to the spectral theory. The approach is unique in that a portion of the total energy decay rate is ascribed to each phase, as is dictated by the exact averaged equations, and results in a transport equation for energy decay rate associated with each phase. What follows is a straightforward definition of a turbulent viscosity for each phase, and accounts for the effect of exchange of fluctuational energy among phases on the turbulent shear viscosity. The model also accounts for the effect of slip momentum transfer among the phases on the production of turbulence kinetic energy and on the tensor character of the Reynolds stress. Collisional effects, when appropriate, are included by superposition. The model reduces to a standard form in limit of a single, pure material, and is expected to do a credible job of describing multiphase turbulent flows in a wide variety of regimes using a single set of coefficients.

B. A. Kashiwa; W. B. VanderHeyden

2000-12-01T23:59:59.000Z

200

Application of automatic differentiation for the simulation of nonisothermal, multiphase flow in geothermal reservoirs  

DOE Green Energy (OSTI)

Simulation of nonisothermal, multiphase flow through fractured geothermal reservoirs involves the solution of a system of strongly nonlinear algebraic equations. The Newton-Raphson method used to solve such a nonlinear system of equations requires the evaluation of a Jacobian matrix. In this paper we discuss automatic differentiation (AD) as a method for analytically computing the Jacobian matrix of derivatives. Robustness and efficiency of the AD-generated derivative codes are compared with a conventional derivative computation approach based on first-order finite differences.

Kim, Jong G.; Finsterle, Stefan

2002-01-08T23:59:59.000Z

Note: This page contains sample records for the topic "multiphase reactive geochemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Performance Evaluation and CFD Simulation of Multiphase Twin-Screw Pumps  

E-Print Network (OSTI)

Twin-screw pumps are economical alternatives to the conventional multiphase system and are increasingly used in the oil and gas industry due to their versatility in transferring the multiphase mixture with varying Gas Void Fraction (GVF). Present work focuses on the experimental and numerical analysis of twin-screw pumps for different operating conditions. Experimental evaluation aims to understand steady state and transient behavior of twin-screw pumps. Detailed steady state evaluation helped form better understanding of twin-screw pumps under different operating conditions. A comparative study of twin-screw pumps and compressors contradicted the common belief that compressor efficiency is better than the efficiency of twin-screw pumps. Transient analysis at high GVF helped incorporate necessary changes in the design of sealflush recirculation loop to improve the efficiency of the pump. The effect of viscosity of the sealflush fluid at high GVF on pump performance was studied. Volumetric efficiency was found to be decreased with increase in viscosity. Flow visualization was aimed to characterize phase distribution along cavities and clearances at low to high GVF. Dynamic pressure variation was studied along the axis of the screw which helped correlate the GVF, velocity and pressure distribution. Complicated fluid flow behavior due to enclosed fluid pockets and interconnecting clearances makes it difficult to numerically simulate the pump. Hence design optimization and performance prediction incorporates only analytical approach and experimental evaluation. Current work represents an attempt to numerically simulate a multiphase twin-screw pump as a whole. Single phase 3D CFD simulation was performed for different pressure rise. The pressure and velocity profile agreed well with previous studies. Results are validated using an analytical approach as well as experimental data. A two-phase CFD simulation was performed for 50% GVF. An Eulerian approach was employed to evaluate multiphase flow behavior. Pressure, velocity, temperature and GVF distributions were successfully predicted using CFD simulation. Bubble size was found to be most dominant parameter, significantly affecting phase separation and leakage flow rate. Better phase separation was realized with increased bubble size, which resulted in decrease in leakage flow rate. CFD results agreed well with experimental data for the bubble size higher than 0.08 mm.

Patil, Abhay

2013-08-01T23:59:59.000Z

202

Triangular flow in heavy ion collisions in a multiphase transport model  

E-Print Network (OSTI)

We obtain a new set of parameters in a multiphase transport (AMPT) model that are able to describe both the charged particle multiplicity density and the elliptic flow measured in Au + Au collisions at center-of-mass energy root(S)NN = 200 GeV at the Relativistic Heavy Ion Collider, although they still give somewhat softer transverse momentum spectra. We then use the model to predict the triangular flow due to fluctuations in the initial collision geometry and study its effect relative to those from other harmonic components of anisotropic flows on the dihadron azimuthal correlations in both central and midcentral collisions.

Xu, Jun; Ko, Che Ming.

2011-01-01T23:59:59.000Z

203

Geophysical monitoring and reactive transport modeling of ureolytically-driven calcium carbonate precipitation  

SciTech Connect

Ureolytically-driven calcium carbonate precipitation is the basis for a promising in-situ remediation method for sequestration of divalent radionuclide and trace metal ions. It has also been proposed for use in geotechnical engineering for soil strengthening applications. Monitoring the occurrence, spatial distribution, and temporal evolution of calcium carbonate precipitation in the subsurface is critical for evaluating the performance of this technology and for developing the predictive models needed for engineering application. In this study, we conducted laboratory column experiments using natural sediment and groundwater to evaluate the utility of geophysical (complex resistivity and seismic) sensing methods, dynamic synchrotron x-ray computed tomography (micro-CT), and reactive transport modeling for tracking ureolytically-driven calcium carbonate precipitation processes under site relevant conditions. Reactive transport modeling with TOUGHREACT successfully simulated the changes of the major chemical components during urea hydrolysis. Even at the relatively low level of urea hydrolysis observed in the experiments, the simulations predicted an enhanced calcium carbonate precipitation rate that was 3-4 times greater than the baseline level. Reactive transport modeling results, geophysical monitoring data and micro-CT imaging correlated well with reaction processes validated by geochemical data. In particular, increases in ionic strength of the pore fluid during urea hydrolysis predicted by geochemical modeling were successfully captured by electrical conductivity measurements and confirmed by geochemical data. The low level of urea hydrolysis and calcium carbonate precipitation suggested by the model and geochemical data was corroborated by minor changes in seismic P-wave velocity measurements and micro-CT imaging; the latter provided direct evidence of sparsely distributed calcium carbonate precipitation. Ion exchange processes promoted through NH{sub 4}{sup +} production during urea hydrolysis were incorporated in the model and captured critical changes in the major metal species. The electrical phase increases were potentially due to ion exchange processes that modified charge structure at mineral/water interfaces. Our study revealed the potential of geophysical monitoring for geochemical changes during urea hydrolysis and the advantages of combining multiple approaches to understand complex biogeochemical processes in the subsurface.

Wu, Y.; Ajo-Franklin, J.B.; Spycher, N.; Hubbard, S.S.; Zhang, G.; Williams, K.H.; Taylor, J.; Fujita, Y.; Smith, R.

2011-07-15T23:59:59.000Z

204

Geophysical Monitoring and Reactive Transport Modeling of Ureolytically-Driven Calcium Carbonate Precipitation  

Science Conference Proceedings (OSTI)

Ureolytically-driven calcium carbonate precipitation is the basis for a promising in-situ remediation method for sequestration of divalent radionuclide and trace metal ions. It has also been proposed for use in geotechnical engineering for soil strengthening applications. Monitoring the occurrence, spatial distribution, and temporal evolution of calcium carbonate precipitation in the subsurface is critical for evaluating the performance of this technology and for developing the predictive models needed for engineering application. In this study, we conducted laboratory column experiments using natural sediment and groundwater to evaluate the utility of geophysical (complex resistivity and seismic) sensing methods, dynamic synchrotron x-ray computed tomography (micro-CT), and reactive transport modeling for tracking ureolytically-driven calcium carbonate precipitation processes under site relevant conditions. Reactive transport modeling with TOUGHREACT successfully simulated the changes of the major chemical components during urea hydrolysis. Even at the relatively low level of urea hydrolysis observed in the experiments, the simulations predicted an enhanced calcium carbonate precipitation rate that was 3-4 times greater than the baseline level. Reactive transport modeling results, geophysical monitoring data and micro-CT imaging correlated well with reaction processes validated by geochemical data. In particular, increases in ionic strength of the pore fluid during urea hydrolysis predicted by geochemical modeling were successfully captured by electrical conductivity measurements and confirmed by geochemical data. The low level of urea hydrolysis and calcium carbonate precipitation suggested by the model and geochemical data was corroborated by minor changes in seismic P-wave velocity measurements and micro-CT imaging; the latter provided direct evidence of sparsely distributed calcium carbonate precipitation. Ion exchange processes promoted through NH4+ production during urea hydrolysis were incorporated in the model and captured critical changes in the major metal species. The electrical phase increases were potentially due to ion exchange processes that modified charge structure at mineral/water interfaces. Our study revealed the potential of geophysical monitoring for geochemical changes during urea hydrolysis and the advantages of combining multiple approaches to understand complex biogeochemical processes in the subsurface.

Yuxin Wu; Jonathan B. Ajo-Franklin; Nicolas Spycher; Susan S. Hubbard; Guoxiang Zhang; Kenneth H. Williams; Joanna Taylor; Yoshiko Fujita; Robert Smith

2011-09-01T23:59:59.000Z

205

Adaptive fully implicit multi-scale finite-volume method for multi-phase flow and transport in heterogeneous porous media  

Science Conference Proceedings (OSTI)

We describe a sequential fully implicit (SFI) multi-scale finite volume (MSFV) algorithm for nonlinear multi-phase flow and transport in heterogeneous porous media. The method extends the recently developed multiscale approach, which is based on an IMPES ... Keywords: coupled flow and transport, finite-volume, heterogeneous porous media, immiscible multi-phase flow, multiscale methods, numerical simulation

P. Jenny; S. H. Lee; H. A. Tchelepi

2006-09-01T23:59:59.000Z

206

Chemically and compositionally modified solid solution disordered multiphase nickel hydroxide positive electrode for alkaline rechargeable electrochemical cells  

DOE Patents (OSTI)

A high capacity, long cycle life positive electrode for use in an alkaline rechargeable electrochemical cell comprising: a solid solution nickel hydroxide material having a multiphase structure that comprises at least one polycrystalline .gamma.-phase including a polycrystalline .gamma.-phase unit cell comprising spacedly disposed plates with at least one chemical modifier incorporated around the plates, the plates having a range of stable intersheet distances corresponding to a 2.sup.+ oxidation state and a 3.5.sup.+, or greater, oxidation state; and at least one compositional modifier incorporated into the solid solution nickel hydroxide material to promote the multiphase structure.

Ovshinsky, Stanford R. (Bloomfield Hills, MI); Corrigan, Dennis (Troy, MI); Venkatesan, Srini (Southfield, MI); Young, Rosa (Troy, MI); Fierro, Christian (Troy, MI); Fetcenko, Michael A. (Rochester Hills, MI)

1994-01-01T23:59:59.000Z

207

A Multiphase, Modular, Bidirectional, Triple-Voltage DC-DC Converter Power Systems  

Science Conference Proceedings (OSTI)

Electrical power systems in future hybrid and fuel cell vehicles may employ three voltage [14 V, 42 V, and high voltage (HV)] nets. These will be necessary to accommodate existing 14-V loads as well as efficiently handle new heavy loads at the 42-V net and a traction drive on the HV bus. A low-cost DC-DC converter was proposed for connecting the three voltage nets. It minimizes the number of switches and their associated gate driver components by using two half-bridges and a high-frequency transformer. Another salient feature is that the half bridge on the 42-V bus is also utilized to provide the 14-V bus by operating at duty ratios around an atypical value of 1/3. Moreover, it makes use of the parasitic capacitance of the switches and the transformer leakage inductance for soft switching. The use of half bridges makes the topology well suited for interleaved multiphase modular configurations as a means to increase the power level because the capacitor legs can be shared. This paper presents simulation and experimental results on an interleaved two-phase arrangement rated at 4.5 kW. Also discussed are the benefits of operating with an atypical duty ratio on the transformer and a preferred multiphase configuration to minimize capacitor ripple currents.

Su, Gui-Jia [ORNL; Tang, Lixin [ORNL

2008-01-01T23:59:59.000Z

208

Multi-Phase CFD Modeling of Solid Sorbent Carbon Capture System  

Science Conference Proceedings (OSTI)

Computational fluid dynamics (CFD) simulations are used to investigate a low temperature post-combustion carbon capture reactor. The CFD models are based on a small scale solid sorbent carbon capture reactor design from ADA-ES and Southern Company. The reactor is a fluidized bed design based on a silica-supported amine sorbent. CFD models using both Eulerian-Eulerian and Eulerian-Lagrangian multi-phase modeling methods are developed to investigate the hydrodynamics and adsorption of carbon dioxide in the reactor. Models developed in both FLUENT® and BARRACUDA are presented to explore the strengths and weaknesses of state of the art CFD codes for modeling multi-phase carbon capture reactors. The results of the simulations show that the FLUENT® Eulerian-Lagrangian simulations (DDPM) are unstable for the given reactor design; while the BARRACUDA Eulerian-Lagrangian model is able to simulate the system given appropriate simplifying assumptions. FLUENT® Eulerian-Eulerian simulations also provide a stable solution for the carbon capture reactor given the appropriate simplifying assumptions.

Ryan, Emily M.; DeCroix, David; Breault, Ronald W.; Xu, Wei; Huckaby, E. D.; Saha, Kringan; Darteville, Sebastien; Sun, Xin

2013-07-30T23:59:59.000Z

209

CFD Simulation and Experimental Testing of Multiphase Flow Inside the MVP Electrical Submersible Pump  

E-Print Network (OSTI)

The MVP is a special type of Electrical Submersible Pumps (ESPs) manufactured by Baker Hughes, model no. G470, and is capable of handling multiphase flow up to 70% Gas Volume Fraction (GVF). Flows at high GVF cause conventional ESPs to surge. However, the special design of the impeller blades of the MVP ESP enables it to handle higher GVF. Dynamic behavior of the multiphase flow is studied experimentally and theoretically for this pump for the first time. In this work, a Computational Fluid Dynamics (CFD) simulation of an entire pump and detailed experimental analysis are performed. Meshing and CFD simulations are performed using the commercially available software ANSYS Fluent. An experimental facility has been designed and constructed to test the pump at different operating conditions. The pump is modeled and tested at two speeds; 3300 and 3600 rpm, using air-water mixtures with GVFs of 0, 5, 10, 25, 32 and 35%. The flow loop is controlled to produce different suction pressures up to 300psi. Pump pressure head is used to validate the CFD model for both single and two phase flows. Single phase CFD model was validated at 100 psi inlet pressure, while two phase models were validated at 200 psi inlet pressure. CFD simulations can predict the behavior of the pump at different speeds, flow rates, GVFs, and inlet pressures. Different diffuser designs are studied and simulated to improve the multistage pump performance. Enhanced diffuser designs increased the pump pressure head to up to 3.2%.

Rasmy Marsis, Emanuel 1983-

2012-12-01T23:59:59.000Z

210

STOMP-ECKEChem: An Engineering Perspective on Reactive Transport in Geologic Media  

Science Conference Proceedings (OSTI)

ECKEChem (Equilibrium, Conservation, Kinetic Equation Chemistry) is a reactive transport module for the STOMP suite of multifluid subsurface flow and transport simulators that was developed from an engineering perspective. STOMP comprises a suite of operational modes that are distinguished by the solved coupled conservation equations with capabilities for a variety of subsurface applications (e.g., environmental remediation and stewardship, geologic sequestration of greenhouse gases, gas hydrate production, and oil shale production). The ECKEChem module was designed to provide integrated reactive transport capabilities across the suite of STOMP simulator operational modes. The initial application for the ECKEChem module was in the simulation of the mineralization reactions that occurred with the injection of supercritical carbon dioxide into deep Columbia River basalt formations, where it was implemented in the STOMP-CO2 simulator. The STOMP-ECKEChem solution approach to modeling reactive transport in multifluid geologic media is founded on an engineering perspective: (1) sequential non-iterative coupling between the flow and reactive transport is sufficient, (2) reactive transport can be modeled by operator splitting with local geochemistry and global transport, (3) geochemistry can be expressed as a system of coupled nonlinear equilibrium, conservation and kinetic equations, (4) a limited number of kinetic equation forms are used in geochemical practice. This chapter describes the conceptual approach to converting a geochemical reaction network into a series of equilibrium, conservation and kinetic equations, the implementation of ECKEChem in STOMP, the numerical solution approach, and a demonstration of the simulator on a complex application involving desorption of uranium from contaminated field-textured sediments.

White, Mark D.; Fang, Yilin

2012-04-04T23:59:59.000Z

211

Testing geochemical modeling codes using New Zealand hydrothermal systems  

DOE Green Energy (OSTI)

Hydrothermal systems in the Taupo Volcanic Zone, North Island, New Zealand are being used as field-based modeling exercises for the EQ3/6 geochemical modeling code package. Comparisons of the observed state and evolution of selected portions of the hydrothermal systems with predictions of fluid-solid equilibria made using geochemical modeling codes will: (1) ensure that we are providing adequately for all significant processes occurring in natural systems; (2) determine the adequacy of the mathematical descriptions of the processes; (3) check the adequacy and completeness of thermodynamic data as a function of temperature for solids, aqueous species and gases; and (4) determine the sensitivity of model results to the manner in which the problem is conceptualized by the user and then translated into constraints in the code input. Preliminary predictions of mineral assemblages in equilibrium with fluids sampled from wells in the Wairakei geothermal field suggest that affinity-temperature diagrams must be used in conjunction with EQ6 to minimize the effect of uncertainties in thermodynamic and kinetic data on code predictions. The kinetics of silica precipitation in EQ6 will be tested using field data from silica-lined drain channels carrying hot water away from the Wairakei borefield.

Bruton, C.J.; Glassley, W.E.; Bourcier, W.L.

1993-12-01T23:59:59.000Z

212

Stream sediment detailed geochemical survey for Date Creek Basin, Arizona  

SciTech Connect

Results of the Date Creek Basin detailed geochemical survey are reported. Field and laboratory data are reported for 239 stream sediment samples. Statistical and areal distributions of uranium and possible uranium-related variables are displayed. A generalized geologic map of the area is provided, and pertinent geologic factors which may be of significance in evaluating the potential for uranium mineralization are briefly discussed. Based on stream sediment geochemical data, significant concentrations of uranium are restricted to the Anderson Mine area. The 84th percentile concentrations of U-FL, U-NT, and U-FL/U-NT combined with low thorium/U-NT values reflect increased mobility and enrichment of uranium in the carbonate host rocks of that area. Elements characteristically associated with the uranium mineralization include lithium and arsenic. No well defined diffusion halos suggesting outliers of similar uranium mineralization were observed from the stream sediment data in other areas of the Date Creek Basin. Significant concentrations of U-FL or U-NT found outside the mine area are generally coincident with low U-FL/U-NT values and high concentrations of zirconium, titanium, and phosphorus. This suggests that the uranium is related to a resistate mineral assemblage derived from surrounding crystalline igneous and metamorphic rocks.

Butz, T.R.; Tieman, D.J.; Grimes, J.G.; Bard, C.S.; Helgerson, R.N.; Pritz, P.M.

1980-06-30T23:59:59.000Z

213

Geochemical and Isotopic Interpretations of Groundwater Flow in the Oasis Valley Flow System, Southern Nevada  

SciTech Connect

This report summarizes the findings of a geochemical investigation of the Pahute Mesa-Oasis Valley groundwater flow system in southwestern Nevada. It is intended to provide geochemical data and interpretations in support of flow and contaminant transport modeling for the Western and Central Pahute Mesa Corrective Action Units.

J.M. Thomas; F.C. Benedict, Jr.; T.P. Rose; R.L. Hershey; J.B. Paces; Z.E. Peterman; I.M. Farnham; K.H. Johannesson; A.K. Singh; K.J. Stetzenbach; G.B. Hudson; J.M. Kenneally; G.F. Eaton; D.K. Smith

2003-01-08T23:59:59.000Z

214

Reactive rules on the web  

Science Conference Proceedings (OSTI)

Reactive rules are used for programming rule-based, reactive systems, which have the ability to detect events and respond to them automatically in a timely manner. Such systems are needed on the Web for bridging the gap between the existing, passive ...

Bruno Berstel; Philippe Bonnard; François Bry; Michael Eckert; Paula-Lavinia P?trânjan

2007-09-01T23:59:59.000Z

215

Multi-organ segmentation from multi-phase abdominal CT via 4D graphs using enhancement, shape and location optimization  

Science Conference Proceedings (OSTI)

The interpretation of medical images benefits from anatomical and physiological priors to optimize computer-aided diagnosis (CAD) applications. Diagnosis also relies on the comprehensive analysis of multiple organs and quantitative measures of soft tissue. ... Keywords: 4D graph, enhancement, multi-phase CT, segmentation, shape

Marius George Linguraru; John A. Pura; Ananda S. Chowdhury; Ronald M. Summers

2010-09-01T23:59:59.000Z

216

Fast computation of multiphase flow in porous media by implicit discontinuous Galerkin schemes with optimal ordering of elements  

Science Conference Proceedings (OSTI)

We present a family of implicit discontinuous Galerkin schemes for purely advective multiphase flow in porous media in the absence of gravity and capillary forces. To advance the solution one time step, one must solve a discrete system of nonlinear equations. ... Keywords: Implicit upwind scheme, Porous media flow, Topological sorting

Jostein R. Natvig; Knut-Andreas Lie

2008-12-01T23:59:59.000Z

217

Reactive Geochemical Transport Modeling of Concentrated Aqueous Solutions: Supplement to TOUGHREACT User's Guide for the Pitzer Ion-Interaction Model  

E-Print Network (OSTI)

144 o C. A water-cooled condenser was attached at the top ofthe end block (at the condenser outflow) is allowed contactis condensed in the condenser, represented by a cooler block

Zhang, Guoxiang; Spycher, Nicolas; Xu, Tianfu; Sonnenthal, Eric; Steefel, Carl

2006-01-01T23:59:59.000Z

218

A Tariff for Reactive Power  

DOE Green Energy (OSTI)

Two kinds of power are required to operate an electric power system: real power, measured in watts, and reactive power, measured in volt-amperes reactive or VARs. Reactive power supply is one of a class of power system reliability services collectively known as ancillary services, and is essential for the reliable operation of the bulk power system. Reactive power flows when current leads or lags behind voltage. Typically, the current in a distribution system lags behind voltage because of inductive loads such as motors. Reactive power flow wastes energy and capacity and causes voltage droop. To correct lagging power flow, leading reactive power (current leading voltage) is supplied to bring the current into phase with voltage. When the current is in phase with voltage, there is a reduction in system losses, an increase in system capacity, and a rise in voltage. Reactive power can be supplied from either static or dynamic VAR sources. Static sources are typically transmission and distribution equipment, such as capacitors at substations, and their cost has historically been included in the revenue requirement of the transmission operator (TO), and recovered through cost-of-service rates. By contrast, dynamic sources are typically generators capable of producing variable levels of reactive power by automatically controlling the generator to regulate voltage. Transmission system devices such as synchronous condensers can also provide dynamic reactive power. A class of solid state devices (called flexible AC transmission system devices or FACTs) can provide dynamic reactive power. One specific device has the unfortunate name of static VAR compensator (SVC), where 'static' refers to the solid state nature of the device (it does not include rotating equipment) and not to the production of static reactive power. Dynamic sources at the distribution level, while more costly would be very useful in helping to regulate local voltage. Local voltage regulation would reduce system losses, increase circuit capacity, increase reliability, and improve efficiency. Reactive power is theoretically available from any inverter-based equipment such as photovoltaic (PV) systems, fuel cells, microturbines, and adjustable-speed drives. However, the installation is usually only economical if reactive power supply is considered during the design and construction phase. In this report, we find that if the inverters of PV systems or the generators of combined heat and power (CHP) systems were designed with capability to supply dynamic reactive power, they could do this quite economically. In fact, on an annualized basis, these inverters and generators may be able to supply dynamic reactive power for about $5 or $6 per kVAR. The savings from the local supply of dynamic reactive power would be in reduced losses, increased capacity, and decreased transmission congestion. The net savings are estimated to be about $7 per kVAR on an annualized basis for a hypothetical circuit. Thus the distribution company could economically purchase a dynamic reactive power service from customers for perhaps $6/kVAR. This practice would provide for better voltage regulation in the distribution system and would provide an alternate revenue source to help amortize the cost of PV and CHP installations. As distribution and transmission systems are operated under rising levels of stress, the value of local dynamic reactive supply is expected to grow. Also, large power inverters, in the range of 500 kW to 1 MW, are expected to decrease in cost as they become mass produced. This report provides one data point which shows that the local supply of dynamic reactive power is marginally profitable at present for a hypothetical circuit. We expect that the trends of growing power flow on the existing system and mass production of inverters for distributed energy devices will make the dynamic supply of reactive power from customers an integral component of economical and reliable system operation in the future.

Kueck, John D [ORNL; Kirby, Brendan J [ORNL; Li, Fangxing [ORNL; Tufon, Christopher [Pacific Gas and Electric Company; Isemonger, Alan [California Independent System Operator

2008-07-01T23:59:59.000Z

219

Federal Energy Management Program: Reactive Maintenance  

NLE Websites -- All DOE Office Websites (Extended Search)

Reactive Reactive Maintenance to someone by E-mail Share Federal Energy Management Program: Reactive Maintenance on Facebook Tweet about Federal Energy Management Program: Reactive Maintenance on Twitter Bookmark Federal Energy Management Program: Reactive Maintenance on Google Bookmark Federal Energy Management Program: Reactive Maintenance on Delicious Rank Federal Energy Management Program: Reactive Maintenance on Digg Find More places to share Federal Energy Management Program: Reactive Maintenance on AddThis.com... Sustainable Buildings & Campuses Operations & Maintenance Federal Requirements Program Management Commissioning Metering Computerized Maintenance Management Systems Maintenance Types Reactive Preventive Predictive Reliability-Centered Major Equipment Types

220

Reactive transport modelling of the interaction of fission product ground contamination with alkaline and cementitious leachates  

Science Conference Proceedings (OSTI)

The fission products Cs-137 and Sr-90 are amongst the most common radionuclides occurring in ground contamination at the UK civil nuclear sites. Such contamination is often associated with alkaline liquids and the mobility of these fission products may be affected by these chemical conditions. Similar geochemical effects may also result from cementitious leachate associated with building foundations and the use of grouts to remediate ground contamination. The behaviour of fission products in these scenarios is a complex interaction of hydrogeological and geochemical processes. A suite of modelling tools have been developed to investigate the behaviour of a radioactive plume containing Cs and Sr. Firstly the effects of sorption due to cementitious groundwater is modelled using PHREEQC. This chemical model is then incorporated into PHAST for the 3-D reactive solute transport modeling. Results are presented for a generic scenario including features and processes that are likely to be relevant to a number of civil UK nuclear sites. Initial results show that modelling can be a very cost-effective means to study the complex hydrogeological and geochemical processes involved. Modelling can help predict the mobility of contaminants in a range of site end point scenarios, and in assessing the consequences of decommissioning activities. (authors)

Kwong, S.; Small, J. [Nexia Solutions Ltd, The British Technology Centre, Sellafield, Seascale, CA20 1PG (United Kingdom)

2007-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "multiphase reactive geochemical" from the National Library of EnergyBeta (NLEBeta).
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221

The hydrogeologic-geochemical model of Cerro Prieto revisited  

DOE Green Energy (OSTI)

As the exploitation of the Cerro Prieto, Mexico, geothermal field continues, there is increasing evidence that the hydrogeologic model developed by Halfman et al. (1984, 1986) presents the basic features controlling the movement of geothermal fluids in the system. At the present time the total installed capacity at Cerro Prieto is 620 MWe requiring the production of more than 10,500 tonnes/hr of a brine-steam mixture. This significant rate of fluid production has resulted in changes in reservoir thermodynamic conditions and in the chemistry of the produced fluids. After reviewing the hydrogeologic-geochemical model of Cerro Prieto, some of the changes observed in the field due to its exploitation are discussed and interpreted on the basis of the model. 21 refs., 11 figs., 1 tab.

Lippmann, M.J.; Halfman, S.E.; Truesdell, A.H.; Manon M., A.

1989-01-01T23:59:59.000Z

222

Holocene deposition in Northwest Providence Channel, Bahamas: a geochemical approach  

SciTech Connect

The origins and depositional history of Holocene sediment in Northwest Providence Channel, Bahamas (NWPC) have been determined using geochemical measurements coupled with textural data, petrographic examination, and scanning electron microscopy. Most of the channel is 200 to 2000 m deep, and nearly 100% of the sediment is calcium carbonate. Shallow water platform sources contribute 75-90% of the Holocene sediment in NWPC. Bank derived sand is most abundant near the platforms (nearly 100%) and is concentrically distributed around a central area of abundant non-platform sand. Bank-derived mud (<62 ..mu..m) accounts for more than 80% of the mud fraction in NWPC. The coarse silt (62-16 ..mu..m), fine silt (16-4 ..mu..m) and clay (< 4 ..mu..m) fractions from LLB (Bight of Abaco) are geochemically distinct from the mud fractions of Great Bahama Bank (GBB). Their distributions in NWPC demonstrate that both platforms are significant sediment contributors to NWPC. The observed sediment distribution clearly indicates that significant off bank transport occurs. With regard to sediment transport, no windward or leeward effects are observed in Holocene sediment deposition. Gravity flow processes are not significant to Holocene deposition. 80% of the present sedimentation rate results from the banktop flooding and confirms that 75%-90% of the Holocene sediment is derived from platform sources. The C-14 dated Holocene sediment layer is approximately 50 cm thick, and its transition with the Pleistocene occurs over a vertical interval of less than 20 cm as a result of mixing by benthonic organisms. This Holocene sediment layer should remain intact to permanently record this banktop episode, and should have a different diagenetic future from the underlying stable (calcite-rich) sediment.

Boardman, M.R.

1978-01-01T23:59:59.000Z

223

Geochemical exploration for uranium in the Red Desert, Wyoming  

SciTech Connect

Geochemical exploration techniques for uranium were performed at a known deposit, the ENQ uranium deposit, which is in arkosic sandstones of the Battle Spring Formation in the Red Desert of Wyoming. Regional gross-gamma aerial data did not indicate the most favorable terrain for follow-up surveys, but instead the radionuclide distribution mapped radioactive mudstones. The /sup 234/U//sup 238/U activity ratio and total uranium concentration in ground water were successful downflow indicators of the ENQ deposit. Helium concentration increased downflow in the ground water flowing from the deposit, while Cu, Pb, and Ba decreased. Radon emanometric techniques generally produced data that coincided with the equivalent uranium concentrations at shallow depth. Helium content in soil was interpreted to reflect local lithology and gaseous migration. Multielement geochemical analyses on soils were effective in delineating the general vicinity of the orebody. Factor analysis was used to recognize three lithologic subgroups. Leachable uranium in soils was the best indicator of subsurface mineralization for the entire subregional area. Equivalent uranium, as determined from the gamma-spectral borehole logs, revealed a consistent dispersion pattern within the host sand of the Battle Spring Formation, whereas gross gamma logs could not detect the subtle gradients in radioelement content. Halo models developed to explain the distribution of helium, radon, radioelements, and trace elements demonstrate uranium itself as the most mobile indicator. Radon and helium appear to reflect local generation from radium accumulations. Vertical leakage due to hydraulic flow against an impermeable barrier is interpreted to be the major secondary redistribution process responsible for the measureable surface signals.

Pacer, J.C.; Bramlett, L.; Moll, S.

1981-05-01T23:59:59.000Z

224

Multi-symplectic relative equilibria, multi-phase wavetrains and coupled NLS equations  

E-Print Network (OSTI)

The paper begins with a geometric formulation of 2-phase wavetrain solutions of coupled nonlinear Schrodinger equations. It is shown that these solutions come in natural 4-parameter families, associated with symmetry, and a geometric instability condition can be deduced from the parameter structure which generalizes Roskes' instability criterion. It is then shown that this geometric structure is universal in the sense that it does not depend on the particular equation, only on the structure of the equations. The theory also extends to the case without symmetry, where small divisors may be present, but gives a new formal geometric framework for multi-phase wavetrains. 1 Introduction This paper has three interrelated parts. It starts by considering a system of coupled nonlinear Schrodinger (cNLS) equations as motivation. Coupled NLS equations are model PDEs which appear in a wide range of wave phenomena, including plasma physics, optics and water waves. The cNLS equations have a basic...

Thomas J. Bridges; Fiona E. Laine-pearson

2000-01-01T23:59:59.000Z

225

Multicomponent, Multiphase Thermodynamics of Swelling Porous Media with Electroquasistatics: I. Macroscale Field Equations  

E-Print Network (OSTI)

A systematic development of the macroscopic field equations (conservation of mass, linear and angular momentum, energy, and Maxwell’s equations) for a multiphase, multicomponent medium is presented. It is assumed that speeds involved are much slower than the speed of light and that the magnitude of the electric field significantly dominates over the magnetic field so that the electroquasistatic form of Maxwell’s equations applies. A mixture formulation is presented for each phase and then averaged to obtain the macroscopic formulation. Species electric fields are considered, however it is assumed that it is the total electric field which contributes to the electrically induced forces and energy. The relationships between species and bulk phase variables and the macroscopic and microscopic variables are given explicitly. The resulting field equations are of relevance to many practical applications including, but not limited to, swelling clays (smectites), biopolymers, biological membranes, pulsed electrophoresis, and chromatography.

Lynn Schreyer Bennethum; John H. Cushman

2001-01-01T23:59:59.000Z

226

TOUGH2: A general-purpose numerical simulator for multiphase fluid and heat flow  

DOE Green Energy (OSTI)

TOUGH2 is a numerical simulation program for nonisothermal flows of multicomponent, multiphase fluids in porous and fractured media. The chief applications for which TOUGH2 is designed are in geothermal reservoir engineering, nuclear waste disposal, and unsaturated zone hydrology. A successor to the TOUGH program, TOUGH2 offers added capabilities and user features, including the flexibility to handle different fluid mixtures, facilities for processing of geometric data (computational grids), and an internal version control system to ensure referenceability of code applications. This report includes a detailed description of governing equations, program architecture, and user features. Enhancements in data inputs relative to TOUGH are described, and a number of sample problems are given to illustrate code applications. 46 refs., 29 figs., 12 tabs.

Pruess, K.

1991-05-01T23:59:59.000Z

227

Circulating fluidized bed hydrodynamics experiments for the multiphase fluid dynamics research consortium (MFDRC).  

Science Conference Proceedings (OSTI)

An experimental program was conducted to study the multiphase gas-solid flow in a pilot-scale circulating fluidized bed (CFB). This report describes the CFB experimental facility assembled for this program, the diagnostics developed and/or applied to make measurements in the riser section of the CFB, and the data acquired for several different flow conditions. Primary data acquired included pressures around the flow loop and solids loadings at selected locations in the riser. Tomographic techniques using gamma radiation and electrical capacitance were used to determine radial profiles of solids volume fraction in the riser, and axial profiles of the integrated solids volume fraction were produced. Computer Aided Radioactive Particle Tracking was used to measure solids velocities, fluxes, and residence time distributions. In addition, a series of computational fluid dynamics simulations was performed using the commercial code Arenaflow{trademark}.

Oelfke, John Barry; Torczynski, John Robert; O'Hern, Timothy John; Tortora, Paul Richard; Bhusarapu, Satish (; ); Trujillo, Steven Mathew

2006-08-01T23:59:59.000Z

228

Investigation of Multiscale and Multiphase Flow, Transport and Reaction in Heavy Oil Recovery Processes  

Science Conference Proceedings (OSTI)

This project is an investigation of various multi-phase and multiscale transport and reaction processes associated with heavy oil recovery. The thrust areas of the project include the following: Internal drives, vapor-liquid flows, combustion and reaction processes, fluid displacements and the effect of instabilities and heterogeneities and the flow of fluids with yield stress. These find respective applications in foamy oils, the evolution of dissolved gas, internal steam drives, the mechanics of concurrent and countercurrent vapor-liquid flows, associated with thermal methods and steam injection, such as SAGD, the in-situ combustion, the upscaling of displacements in heterogeneous media and the flow of foams, Bingham plastics and heavy oils in porous media and the development of wormholes during cold production.

Yortsos, Yanis C.

2001-08-07T23:59:59.000Z

229

Progress in the Development of Compressible, Multiphase Flow Modeling Capability for Nuclear Reactor Flow Applications  

Science Conference Proceedings (OSTI)

In nuclear reactor safety and optimization there are key issues that rely on in-depth understanding of basic two-phase flow phenomena with heat and mass transfer. Within the context of multiphase flows, two bubble-dynamic phenomena – boiling (heterogeneous) and flashing or cavitation (homogeneous boiling), with bubble collapse, are technologically very important to nuclear reactor systems. The main difference between boiling and flashing is that bubble growth (and collapse) in boiling is inhibited by limitations on the heat transfer at the interface, whereas bubble growth (and collapse) in flashing is limited primarily by inertial effects in the surrounding liquid. The flashing process tends to be far more explosive (and implosive), and is more violent and damaging (at least in the near term) than the bubble dynamics of boiling. However, other problematic phenomena, such as crud deposition, appear to be intimately connecting with the boiling process. In reality, these two processes share many details.

R. A. Berry; R. Saurel; F. Petitpas; E. Daniel; O. Le Metayer; S. Gavrilyuk; N. Dovetta

2008-10-01T23:59:59.000Z

230

Reactivity of heat treated chars  

DOE Green Energy (OSTI)

Reactivities of a number of chars produced from American coals varying in rank from lignite to anthracite have been measured in air, CO/sub 2/, steam and H/sub 2/. The variables chosen for the study were: rank of the parent coal, inorganic matter content, particle size, reaction temperature and pressure as well as heat treatment conditions used during char preparation. In all gasification atmospheres studied, reactivity plots for different chars are essentially of the same general shape and have three distinct regions. The reaction rate first increases slowly with time. The plot then goes through a maximum in slope, followed by a lengthy region of decreasing slope as burn-off approaches 100 percent. The shape of the burn-off curves can be explained on the basis of what is known about the development of porosity and surface area in microporous chars as they undergo gasification. Using an adjustable time parameter, equations have been developed which successfully correlate the reactivity data. Char reactivity decreases, in general, with increase in rank of the parent coal. Reactivities of chars in air, CO/sub 2/ and steam increase over 150-fold in going from a low volatile bituminous to a lignite parent coal; the spread in char reactivities in H/sub 2/ is only 30-fold. Removal of inorganic matter from coal precursors prior to their charring or from chars produced from the raw coals has a marked effect on char reactivity and surface area. Removal of inorganic matter (by acid washing) decreases, in general, reactivity of chars produced from lower rank coals, whereas reactivities of chars derived from higher rank coals increase.

Mahajan, O. P.; Walker, Jr., P. L.

1977-01-01T23:59:59.000Z

231

DENSE MULTIPHASE FLOW SIMULATION: CONTINUUM MODEL FOR POLY-DISPERSED SYSTEMS USING KINETIC THEORY  

SciTech Connect

The overall objective of the project was to verify the applicability of the FCMOM approach to the kinetic equations describing the particle flow dynamics. For monodispersed systems the fundamental equation governing the particle flow dynamics is the Boltzmann equation. During the project, the FCMOM was successfully applied to several homogeneous and in-homogeneous problems in different flow regimes, demonstrating that the FCMOM has the potential to be used to solve efficiently the Boltzmann equation. However, some relevant issues still need to be resolved, i.e. the homogeneous cooling problem (inelastic particles cases) and the transition between different regimes. In this report, the results obtained in homogeneous conditions are discussed first. Then a discussion of the validation results for in-homogeneous conditions is provided. And finally, a discussion will be provided about the transition between different regimes. Alongside the work on development of FCMOM approach studies were undertaken in order to provide insights into anisotropy or particles kinetics in riser hydrodynamics. This report includes results of studies of multiphase flow with unequal granular temperatures and analysis of momentum re-distribution in risers due to particle-particle and fluid-particle interactions. The study of multiphase flow with unequal granular temperatures entailed both simulation and experimental studies of two particles sizes in a riser and, a brief discussion of what was accomplished will be provided. And finally, a discussion of the analysis done on momentum re-distribution of gas-particles flow in risers will be provided. In particular a discussion of the remaining work needed in order to improve accuracy and predictability of riser hydrodynamics based on two-fluid models and how they can be used to model segregation in risers.

Moses Bogere

2011-08-31T23:59:59.000Z

232

Method and system for measuring multiphase flow using multiple pressure differentials  

DOE Patents (OSTI)

An improved method and system for measuring a multiphase flow in a pressure flow meter. An extended throat venturi is used and pressure of the multiphase flow is measured at three or more positions in the venturi, which define two or more pressure differentials in the flow conduit. The differential pressures are then used to calculate the mass flow of the gas phase, the total mass flow, and the liquid phase. The method for determining the mass flow of the high void fraction fluid flow and the gas flow includes certain steps. The first step is calculating a gas density for the gas flow. The next two steps are finding a normalized gas mass flow rate through the venturi and computing a gas mass flow rate. The following step is estimating the gas velocity in the venturi tube throat. The next step is calculating the pressure drop experienced by the gas-phase due to work performed by the gas phase in accelerating the liquid phase between the upstream pressure measuring point and the pressure measuring point in the venturi throat. Another step is estimating the liquid velocity in the venturi throat using the calculated pressure drop experienced by the gas-phase due to work performed by the gas phase. Then the friction is computed between the liquid phase and a wall in the venturi tube. Finally, the total mass flow rate based on measured pressure in the venturi throat is calculated, and the mass flow rate of the liquid phase is calculated from the difference of the total mass flow rate and the gas mass flow rate.

Fincke, James R. (Idaho Falls, ID)

2001-01-01T23:59:59.000Z

233

Progress Report, December 2010: Improved Site Characterization And Storage Prediction Through Stochastic Inversion Of Time-Lapse Geophysical And Geochemical Data  

Science Conference Proceedings (OSTI)

Over the last project six months, our project activities have concentrated on three areas: (1) performing a stochastic inversion of pattern 16 seismic data to deduce reservoir permeability, (2) development of the geochemical inversion strategy and implementation of associated software, and (3) completing the software implementation of TProGS and the geostatistical analysis that provides the information needed when using the software to produce realizations of the Midale reservoir. The report partially the following deliverables: D2: Model development: MCMC tool (synthetic fluid chemistry data); deliverable completed. D4: Model development/verification: MCMC tool (TProGS, field seismic/chemistry data) work product; deliverable requirements partially fulfilled. D5: Field-based single-pattern simulations work product; deliverable requirements partially fulfilled. When completed, our completed stochastic inversion tool will explicitly integrate reactive transport modeling, facies-based geostatistical methods, and a novel stochastic inversion technique to optimize agreement between observed and predicted storage performance. Such optimization will be accomplished through stepwise refinement of: (1) the reservoir model - principally its permeability magnitude and heterogeneity - and (2) geochemical parameters - primarily key mineral volume fractions and kinetic data. We anticipate that these refinements will facilitate significantly improved history matching and forward modeling of CO{sub 2} storage. Our tool uses the Markov Chain Monte Carlo (MCMC) methodology. Deliverable D1, previously submitted as a report titled ''Development of a Stochastic Inversion Tool To Optimize Agreement Between The Observed And Predicted Seismic Response To CO{sub 2} Injection/Migration in the Weyburn-Midale Project'' (Ramirez et al., 2009), described the stochastic inversion approach that will identify reservoir models that optimize agreement between the observed and predicted seismic response. The software that implements this approach has been completed, tested, and used to process seismic data from pattern 16. A previously submitted report titled ''Model verification: synthetic single pattern simulations using seismic reflection data'', Ramirez et al. 2010, partially fulfilled deliverable D3 by summarizing verification activities that evaluate the performance of the seismic software and its ability to recover reservoir model permeabilities using synthetic seismic reflection data. A future progress report will similarly describe summarizing verification activities of the geochemical inversion software, thereby completing deliverable D3. This document includes a chapter that shows and discusses permeability models produced by seismic inversion that used seismic data from pattern 16 in Phase 1A. It partially fulfills deliverable D5: Field-based single-pattern simulations work product. The D5 work product is supposed to summarize the results of applying NUFT/MCMC to refine the reservoir model and geochemical parameters by optimizing observation/prediction agreement for the seismic/geochemical response to CO{sub 2} injection/migration within a single pattern of Phase 1A/1B. A future progress report will show inversion results for the same pattern using geochemical data, thereby completing deliverable D5. This document also contains a chapter that fulfills deliverable D2: Model development: MCMC tool (synthetic fluid chemistry data). The chapter will summarize model development activities required to facilitate application of NUFT/MCMC to optimize agreement between the observed and predicted geochemical response to CO{sub 2} injection/migration. Lastly, this document also contains a chapter that partially fulfills deliverable D4: Model development/verification: MCMC tool (TProGS, field seismic/chemistry data) work product. This work product is supposed to summarize model development activities required for (1) application of TProGS to Weyburn, (2) use of TProGS within the MCMC tool, and (3) application of the MCMC tool to address field seismic and g

Ramirez, A; Mcnab, W; Carle, S; Hao, Y; White, D; Johnson, J

2010-12-17T23:59:59.000Z

234

Pore-scale imaging and lattice Boltzmann modeling of single- and multi-phase flow in fractured and mixed-wet permeable media.  

E-Print Network (OSTI)

??Three investigations of pore-scale single-phase and multiphase flow in fractured porous media and mixed-wet porous media are presented here. With an emphasis on validating and… (more)

Landry, Christopher

2013-01-01T23:59:59.000Z

235

Geochemical Data on Waters, Gases, Scales, and Rocks from the Dixie Valley  

Open Energy Info (EERE)

Geochemical Data on Waters, Gases, Scales, and Rocks from the Dixie Valley Geochemical Data on Waters, Gases, Scales, and Rocks from the Dixie Valley Region, Nevada (1996-1999) Jump to: navigation, search OpenEI Reference LibraryAdd to library Report: Geochemical Data on Waters, Gases, Scales, and Rocks from the Dixie Valley Region, Nevada (1996-1999) Abstract This report tabulates an extensive geochemical database on waters, gases, scales,rocks, and hot-spring deposits from the Dixie Valley region, Nevada. The samples fromwhich the data were obtained were collected and analyzed during 1996 to 1999. Thesedata provide useful information for ongoing and future investigations on geothermalenergy, volcanism, ore deposits, environmental issues, and groundwater quality in thisregion. Authors Los Alamos National Laboratory and NM Published

236

Geochemical heterogeneity in the Hawaiian plume : constraints from Hawaiian volcanoes and Emperor seamounts  

E-Print Network (OSTI)

The 6000-km long, age-progressive linear Hawaii-Emperor Chain is one of the best defined hotspot tracks. This hotspot track plays an important role in the plume hypothesis. In this research, geochemical data on the ...

Huang, Shichun

2005-01-01T23:59:59.000Z

237

The dynamics of oceanic transform faults : constraints from geophysical, geochemical, and geodynamical modeling  

E-Print Network (OSTI)

Segmentation and crustal accretion at oceanic transform fault systems are investigated through a combination of geophysical data analysis and geodynamical and geochemical modeling. Chapter 1 examines the effect of fault ...

Gregg, Patricia Michelle Marie

2008-01-01T23:59:59.000Z

238

Migratory patterns of American shad (Alosa sapidissima) revealed by natural geochemical tags in otoliths  

E-Print Network (OSTI)

Geochemical signatures in the otoliths of diadromous fishes may allow for retrospective analyses of natal origins. In an assessment of river-specific signatures in American shad (Alosa sapidissima), an anadromous clupeid ...

Walther, Benjamin (Benjamin Dwaine)

2007-01-01T23:59:59.000Z

239

Reservoir simulation and geochemical study of Cerro Prieto I wells  

DOE Green Energy (OSTI)

Combined reservoir simulation and geochemical data analysis are used to investigate the effects of recharge and other reservoir processes occurring in the western part of the Cerro Prieto, Mexico, geothermal field (i.e., Cerro Prieto I area). Enthalpy-based temperatures and bottomhole temperatures are calculated based on simplified models of the system, considering different reservoir boundary conditions and zones of contrasting initial temperatures and reservoir properties. By matching the computed trends with geothermometer-based temperature and enthalpy histories of producing wells, the main processes active in the western area of Cerro Prieto are identified. This part of the geothermal system is strongly influenced by nearby groundwater aquifers; cooler waters readily recharge the reservoirs. In response to exploitation, the natural influx of cold water into the shallower alpha reservoir is mainly from the west and down Fault L, while the recharge to the deeper beta reservoir in this part of the field, seems to be only lateral, from the west and possibly south. 11 refs., 12 figs.

Lippmann, M.J. (Lawrence Berkeley Lab., CA (USA)); Truesdell, A.H. (Geological Survey, Menlo Park, CA (USA))

1990-03-01T23:59:59.000Z

240

Experimental assessment and modeling of organic compound interphase mass-transfer rates in multiphase subsurface systems. Progress report  

SciTech Connect

During the initial eight month period of this grant, work has been conducted on all facets of the project. Significant progress has been made in the design, construction and testing of the experimental apparatus. Investigation of methods for characterizing the physical forms of non-aqueous phase liquid (NAPL) residuals (globules or blobs) has led to a narrowing of possible approaches. Development of a numerical simulator that accomodates multiphase transport with mass transfer rate interactions is well underway.

Weber, W.J. Jr.; Abriola, L.M.

1990-03-15T23:59:59.000Z

Note: This page contains sample records for the topic "multiphase reactive geochemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Investigation of a Multiphase Twin-screw Pump Operating at High Gas Volume Fractions  

E-Print Network (OSTI)

The use of twin-screw pumps for moving fluids is not new technology but its application to wet gas compression (high gas volume fraction [GVF]) is still considered relatively new. There are many advantages for using twin-screw pumps for oil field applications; three of the immediate improvements include reducing hardware costs, reducing well bore pressure, and producing a pressure boost to move the product to a central collection facility. While there are many advantages to using twin-screw pumps in wet gas applications, there are some problems that have been encountered while operating at high GVFs. When operating at high GVF, over 95 percent twin-screw pumps experience a severe loss of efficiency and an increase of operating temperature. A common way to increase the efficiency while operating in the high GVF range includes adding a liquid recirculation system where a portion of liquid is stored downstream of the pump and is injected into the pump inlet. These systems lower the effective GVF of the multiphase fluid below 95 percent in order to increase the pump efficiency. The first objective is to characterize the performance of a twin-screw pump fitted with a liquid recirculation system while operating under high GVF conditions. The second objective is to investigate the transient heat rise associated with high GVF operation. While traditional twin-screw pumps can be fitted with a liquid recirculation system to allow them to operate under high GVF conditions the pumps themselves are not optimized for wet gas compression and still suffer performance penalties. The results of this investigation show that the liquid recirculation system can allow the pump to operate under high GVF but the heat added to the system reduces the systems efficiency. Without a method of removing the heat generated in the pumping process the pump will not run at its optimal efficiency. The following investigation provides recommendations for further research in area of multiphase pumping using twin-screw pumps based on the characterization and transient studies provided in this thesis.

Kroupa, Ryan Daniel

2011-05-01T23:59:59.000Z

242

Studies on multi-phase equilibrium separation of hydrocarbon/water systems  

E-Print Network (OSTI)

Equations of State (EOS) have been used successfully in compositional simulators to describe phase behavior of reservoir crude and gas condensates without water. The three-phase behavior of water/reservoir crude oils both at reservoir and steam flooding temperature has not yet been successfully predicted by an EOS. Recent publications show that incorporation of the association concept into simple cubic equations such as Peng-Robinson EOS significantly improves phase behavior prediction of water/hydrocarbon and nonhydrate systems, but there are still some numerical difficulties in the pre-diction of three phase flash equilibria. In this thesis we presented, an efficient procedure that will help us eliminate common numerical difficulties in predicting three-phase equilibria for systems containing water, and simplify the programming technique. This scheme checks the existence of three-phase flash at given reservoir conditions, and if three-phase flash (vapor-oleic-aqueous) doesn't exist, it automatically switches to check correct type of two-phase flash (vapor-oleic, vapor-aqueous, or oleic-aqueous). This convergence scheme is used in an EOS-simulator (VLLESIM), which uses nine different EOS's and van der Waals mixing rules, to accurately describe multi-phase equilibrium separation of hydrocarbon/water systems. VLLESIM will be validated with literature data and experimental results obtained from two different experimental setups, for different multi-component hydrocarbon/water systems, for hydrocarbon component varying from C6 to C20. PVT-VLLE apparatus can provide on-line compositional analysis and phase volumes of all equilibrium phases for temperatures up to 350 'F and an Isochoric Steam Distillation Cell (ISDC) can provide only vapor phase compositions, but it can be used up to 500 'F. VLLESIM will then be used to study the effect of temperature, pressure and molecular weight of hydrocarbon components on multiphase equilibria of different hydrocarbon/water systems. Detailed analysis is also provided in this thesis, of the effect of increasing concentration of different hydrocarbon components on the size of the three-phase region for ranges of temperature and pressure mostly prevalent under reservoir conditions.

Chawla, Inderjit Singh

1995-01-01T23:59:59.000Z

243

Ensemble phase averaging equations for multiphase flows in porous media, part I: the bundle-of-tubes model  

Science Conference Proceedings (OSTI)

A bundle-of-tubes construct is used as a model system to study ensemble averaged equations for multiphase flow in a porous material. Momentum equations for the fluid phases obtained from the method are similar to Darcy's law, but with additional terms. We study properties of the additional terms, and the conditions under which the averaged equations can be approximated by the diffusion model or the extended Darcy's law as often used in models for multiphase flows in porous media. Although the bundle-of-tubes model is perhaps the simplest model for a porous material, the ensemble averaged equation technique developed in this paper assumes the very same form in more general treatments described in Part 2 of the present work (Zhang 2009). Any model equation system intended for the more general cases must be understood and tested first using simple models. The concept of ensemble phase averaging is dissected here in physical terms, without involved mathematics through its application to the idealized bundle-of-tubes model for multiphase flow in porous media.

Yang, Dali [Los Alamos National Laboratory; Zhang, Duan [Los Alamos National Laboratory; Currier, Robert [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

244

Investigating the potential for long-term permeable reactive barrier (PRB) monitoring from the electrical signatures associated with the reduction in reactive iron performance  

SciTech Connect

The objective of this work was to conduct laboratory and field experiments to determine the sensitivity of low frequency electrical measurements (resistivity and induced polarization) to the processes of corrosion and precipitation that are believed to limit permeable reactive barrier (PRB) performance. The research was divided into four sets of experiments that were each written up and submitted to a peer-reviewed journal: [1] A laboratory experiment to define the controls of aqueous chemistry (electrolyte activity; pH; valence) and total zero valent iron (Fe0) available surface area on the electrical properties of Fe0 columns. [2] A laboratory experiment to determine the impact of corrosion and precipitation on the electrical response of synthetic Fe0 columns as a result of geochemical reactions with NaSO4 and NaCO3 electrolytes. [3] Laboratory experiments on a sequence of cores retrieved from the Kansas City PRB to determine the magnitude of electrical and geochemical changes within a field active PRB after eight years of operation [4] Field-scale cross borehole resistivity and induced polarization monitoring of the Kansas City PRB to evaluate the potential of electrical imaging as a technology for non-invasive, long-term monitoring of indicators of reduced PRB performance This report first summarizes the findings of the four major experiments conducted under this research. The reader is referred to the four papers in Appendices 1-4 for a full description of each experiment, including motivation and significance, technical details, findings and implications. The deliverables of the project, including the publications, conference papers and new collaborative arrangements that have resulted are then described. Appendices 5-6 contain two technical reports written by co-PI Korte describing (1) supporting geochemical measurements, and (2) the coring procedure, conducted at the Kansas City PRB as part of this project.

Slater, Lee D.; Korte, N.; Baker, J.

2005-12-14T23:59:59.000Z

245

DETERMINATION OF SPECIFIC NEUTRONIC REACTIVITY  

DOE Patents (OSTI)

A method is given for production-line determination of the specific neutronic reactivity of such objects as individual nuclear fuel or neutron absorber elements and is notable for rapidity and apparatus simplicity. The object is incorporated in a slightly sub-critical chain fission reactive assembly having a discrete neutron source, thereby establishing a K/sub eff/ within the crucial range of 0.95 to 0.995. The range was found to afford, uniquely, flux- transient damped response in a niatter of seconds simultaneously with acceptable analytical sensitivity. The resulting neutron flux measured at a situs spaced from both object and source within the assembly serves as a calibrable indication of said reactivity.

Dessauer, G.

1960-05-10T23:59:59.000Z

246

Multiphase Modeling of Flow, Transport, and Biodegradation in a Mesoscale Landfill Bioreactor  

DOE Green Energy (OSTI)

The need to control gas and leachate production and minimize refuse volume in municipal solid waste landfills has motivated the development of landfill simulation models to predict and design optimal treatment processes. We have developed a multiphase and multicomponent nonisothermal module called T2LBM for the three-dimensional TOUGH2 flow and transport simulator. T2LBM can be used to simulate aerobic or anaerobic biodegradation of municipal solid waste and the associated flow and transport of gas and liquid through the refuse mass. Acetic acid is used as a proxy for all biodegradable substrates in the refuse. T2LBM incorporates a Monod kinetic rate law for the biodegradation of acetic acid by either aerobic or anaerobic microbes as controlled by the local oxygen concentration. We have verified the model against published data, and applied it to our own mesoscale laboratory aerobic landfill bioreactor experiments. We observe spatial variability of flow and biodegradation consistent with permeability heterogeneity and the geometry of the radial grid. The model is capable of matching results of a shut-in test where the respiration of the system is measured over time.

Oldenburg, Curtis M.; Borglin, Sharon E.; Hazen, Terry C.

2002-02-01T23:59:59.000Z

247

Visualizing multiphase flow and trapped fluid configurations in a model three-dimensional porous medium  

E-Print Network (OSTI)

We report an approach to fully visualize the flow of two immiscible fluids through a model three-dimensional (3D) porous medium at pore-scale resolution. Using confocal microscopy, we directly image the drainage of the medium by the non-wetting oil and subsequent imbibition by the wetting fluid. During imbibition, the wetting fluid pinches off threads of oil in the narrow crevices of the medium, forming disconnected oil ganglia. Some of these ganglia remain trapped within the medium. By resolving the full 3D structure of the trapped ganglia, we show that the typical ganglion size, and the total amount of residual oil, decreases as the capillary number Ca increases; this behavior reflects the competition between the viscous pressure in the wetting fluid and the capillary pressure required to force oil through the pores of the medium. This work thus shows how pore-scale fluid dynamics influence the trapped fluid configurations in multiphase flow through 3D porous media.

Amber T. Krummel; Sujit S. Datta; Stefan Münster; David A. Weitz

2013-01-21T23:59:59.000Z

248

Visualizing multiphase flow and trapped fluid configurations in a model three-dimensional porous medium  

E-Print Network (OSTI)

We report an approach to fully visualize the flow of two immiscible fluids through a model three-dimensional (3D) porous medium at pore-scale resolution. Using confocal microscopy, we directly image the drainage of the medium by the non-wetting oil and subsequent imbibition by the wetting fluid. During imbibition, the wetting fluid pinches off threads of oil in the narrow crevices of the medium, forming disconnected oil ganglia. Some of these ganglia remain trapped within the medium. By resolving the full 3D structure of the trapped ganglia, we show that the typical ganglion size, and the total amount of residual oil, decreases as the capillary number Ca increases; this behavior reflects the competition between the viscous pressure in the wetting fluid and the capillary pressure required to force oil through the pores of the medium. This work thus shows how pore-scale fluid dynamics influence the trapped fluid configurations in multiphase flow through 3D porous media.

Krummel, Amber T; Münster, Stefan; Weitz, David A; 10.1002/aic.14005

2013-01-01T23:59:59.000Z

249

Development of Approach to Estimate Volume Fraction of Multiphase Material Using Dielectrics  

E-Print Network (OSTI)

Most engineering as well as pavement materials are composites composed of two or more components to obtain a variety of solid properties to support internal and external loading. The composite materials rely on physical or chemical properties and volume fraction of each component. While the properties can be identified easily, the volume fraction is hard to be estimated due to the volumetric variation during the performance in the field. Various test procedures have been developed to measure the volume fractions; however, they depend on subjective determination and judgment. As an alternative, electromagnetic technique using dielectric constant was developed to estimate the volume fraction. Empirical and mechanistic approaches were used to relate the dielectric constant and volume fraction. While the empirical models are not very accurate in all cases, the mechanistic models require assumptions of constituent dielectric constants. For those reasons, the existing approaches might produce less accurate estimate of volume fraction. In this study, a mechanistic-based approach using the self consistent scheme was developed to be applied to multiphase materials. The new approach was based on calibrated dielectric constant of components to improve results without any assumptions. Also, the system identification was used iteratively to solve for dielectric parameters and volume fraction at each step. As the validation performed to verify the viability of the new approach using soil mixture and portland cement concrete, it was found that the approach has produced a significant improvement in the accuracy of the estimated volume fraction.

Lee, Sang Ick

2010-05-01T23:59:59.000Z

250

GEOCHEMICAL MODELING OF F AREA SEEPAGE BASIN COMPOSITION AND VARIABILITY  

SciTech Connect

From the 1950s through 1989, the F Area Seepage Basins at the Savannah River Site (SRS) received low level radioactive wastes resulting from processing nuclear materials. Discharges of process wastes to the F Area Seepage Basins followed by subsequent mixing processes within the basins and eventual infiltration into the subsurface resulted in contamination of the underlying vadose zone and downgradient groundwater. For simulating contaminant behavior and subsurface transport, a quantitative understanding of the interrelated discharge-mixing-infiltration system along with the resulting chemistry of fluids entering the subsurface is needed. An example of this need emerged as the F Area Seepage Basins was selected as a key case study demonstration site for the Advanced Simulation Capability for Environmental Management (ASCEM) Program. This modeling evaluation explored the importance of the wide variability in bulk wastewater chemistry as it propagated through the basins. The results are intended to generally improve and refine the conceptualization of infiltration of chemical wastes from seepage basins receiving variable waste streams and to specifically support the ASCEM case study model for the F Area Seepage Basins. Specific goals of this work included: (1) develop a technically-based 'charge-balanced' nominal source term chemistry for water infiltrating into the subsurface during basin operations, (2) estimate the nature of short term and long term variability in infiltrating water to support scenario development for uncertainty quantification (i.e., UQ analysis), (3) identify key geochemical factors that control overall basin water chemistry and the projected variability/stability, and (4) link wastewater chemistry to the subsurface based on monitoring well data. Results from this study provide data and understanding that can be used in further modeling efforts of the F Area groundwater plume. As identified in this study, key geochemical factors affecting basin chemistry and variability included: (1) the nature or chemistry of the waste streams, (2) the open system of the basins, and (3) duration of discharge of the waste stream types. Mixing models of the archetype waste streams indicated that the overall basin system would likely remain acidic much of the time. Only an extended periods of predominantly alkaline waste discharge (e.g., >70% alkaline waste) would dramatically alter the average pH of wastewater entering the basins. Short term and long term variability were evaluated by performing multiple stepwise modeling runs to calculate the oscillation of bulk chemistry in the basins in response to short term variations in waste stream chemistry. Short term (1/2 month and 1 month) oscillations in the waste stream types only affected the chemistry in Basin 1; little variation was observed in Basin 2 and 3. As the largest basin, Basin 3 is considered the primary source to the groundwater. Modeling showed that the fluctuation in chemistry of the waste streams is not directly representative of the source term to the groundwater (i.e. Basin 3). The sequence of receiving basins and the large volume of water in Basin 3 'smooth' or nullify the short term variability in waste stream composition. As part of this study, a technically-based 'charge-balanced' nominal source term chemistry was developed for Basin 3 for a narrow range of pH (2.7 to 3.4). An example is also provided of how these data could be used to quantify uncertainty over the long term variations in waste stream chemistry and hence, Basin 3 chemistry.

Millings, M.; Denham, M.; Looney, B.

2012-05-08T23:59:59.000Z

251

Geochemical interpretation of Kings Mountain, North Carolina, orientation area  

SciTech Connect

An orientation study has been made of uranium occurrences in the area of Kings Mountain, North Carolina. This is one of the orientation studies of known uranium occurrences that are being conducted in several geologic provinces and under various climatic (weathering) conditions to provide the technical basis for design and interpretation of NURE geochemical reconnaissance programs. The Kings Mountain area was chosen for study primarily because of the reported presence of high-uranium monazite. This 750-mi/sup 2/ area is in the deeply weathered southern Appalachian Piedmont and spans portions of the Inner Piedmont, Kings Mountain, and Charlotte geologic belts. Uranium concentration maps for ground and surface water samples clearly outline the outcrop area of the Cherryville Quartz Monzonite with highs up to 10 ppb uranium near the reported uraninite. Several surface water samples appear to be anomalous because of trace industrial contamination. Uranium concentration maps for -100 to +200 mesh stream sediments indicate the area of monazite abundance. Several samples with >100 ppM uranium content appear to be high in uranium-rich resistate minerals. When the uranium content of sediment samples is ratioed to the sum of Hf, Dy, and Th, the anomaly pattern shifts to coincide with uranium highs in ground and surface water samples. False anomalies from concentrations of monazite (Ce,ThPO/sub 4/), xenotime (Y,DyPO/sub 4/), and zircon (Zr,HfSiO/sub 4/) in stream sediment samples can thus be eliminated. Residual anomalies should be related to unusual uranium enrichment of these common minerals or to the presence of an uncommon uranium-rich mineral. Tantalum, beryllium, and tin in stream sediments correspond to high concentrations of uranium in stream and ground water but not to uranium in sediments. In an initial reconnaissance, several media should be sampled, and it is essential to correct uranium in sediments for the sample mineralogy.

Price, V.; Ferguson, R.B.

1977-01-01T23:59:59.000Z

252

Origin and geochemical evolution of the Michigan basin brine  

Science Conference Proceedings (OSTI)

Chemical and isotopic data were collected on 126 oil field brine samples and were used to investigate the origin and geochemical evolution of water in 8 geologic formations in the Michigan basin. Two groups of brine are found in the basin, the Na-Ca-Cl brine in the upper Devonian formations, and Ca-Na-Cl brine from the lower Devonian and Silurian aged formations. Water in the upper Devonian Berea, Traverse, and Dundee formations originated from seawater concentrated into halite facies. This brine evolved by halite precipitation, dolomitization, aluminosilicate reactions, and the removal of SO{sub 4} by bacterial action or by CaSO{sub 4} precipitation. The stable isotopic composition (D, O) is thought to represent dilution of evapo-concentrated seawater by meteoric water. Water in the lower Devonian Richfield, Detroit River Group, and Niagara-Salina formations is very saline Ca-Na-Cl brine. Cl/Br suggest it originated from seawater concentrated through the halite and into the MgSO{sub 4} salt facies, with an origin linked to the Silurian and Devonian salt deposits. Dolomitization and halite precipitation increased the Ca/Na, aluminosilicate reactions removed K, and bacterial action or CaSO{sub 4} precipitation removed SO{sub 4} from this brine. Water chemistry in the Ordovician Trenton-Black River formations indicates dilution of evapo-concentrated seawater by fresh or seawater. Possible saline end-members include Ordovician seawater, present-day upper Devonian brine, or Ca-Cl brine from the deeper areas in the basin.

Wilson, T.P.

1989-01-01T23:59:59.000Z

253

Treating water-reactive wastes  

DOE Green Energy (OSTI)

Some compounds and elements, such as lithium hydride, magnesium, sodium, and calcium react violently with water to generate much heat and produce hydrogen. The hydrogen can ignite or even form an explosive mixture with air. Other metals may react rapidly only if they are finely divided. Some of the waste produced at Los Alamos National Laboratory includes these metals that are contaminated with radioactivity. By far the greatest volume of water-reactive waste is lithium hydride contaminated with depleted uranium. Reactivity of the water-reactive wastes is neutralized with an atmosphere of humid nitrogen, which prevents the formation of an explosive mixture of hydrogen and air. When we adjust the temperature of the nitrogen and the humidifier, the nitrogen can be more or less humid, and the rate of reaction can be adjusted and controlled. Los Alamos has investigated the rates of reaction of lithium hydride as a function of the temperature and humidity, and, as anticipated, they in with in temperature and humidity. Los Alamos will investigate other variables. For example, the nitrogen flow will be optimized to conserve nitrogen and yet keep the reaction rates high. Reaction rates will be determined for various forms of lithium waste, from small chips to powder. Bench work will lead to the design of a skid-mounted process for treating wastes. Other water-reactive wastes will also be investigated.

Lussiez, G.W.

1993-01-01T23:59:59.000Z

254

Treating water-reactive wastes  

DOE Green Energy (OSTI)

Some compounds and elements, such as lithium hydride, magnesium, sodium, and calcium react violently with water to generate much heat and produce hydrogen. The hydrogen can ignite or even form an explosive mixture with air. Other metals may react rapidly only if they are finely divided. Some of the waste produced at Los Alamos National Laboratory includes these metals that are contaminated with radioactivity. By far the greatest volume of water-reactive waste is lithium hydride contaminated with depleted uranium. Reactivity of the water-reactive wastes is neutralized with an atmosphere of humid nitrogen, which prevents the formation of an explosive mixture of hydrogen and air. When we adjust the temperature of the nitrogen and the humidifier, the nitrogen can be more or less humid, and the rate of reaction can be adjusted and controlled. Los Alamos has investigated the rates of reaction of lithium hydride as a function of the temperature and humidity, and, as anticipated, they in with in temperature and humidity. Los Alamos will investigate other variables. For example, the nitrogen flow will be optimized to conserve nitrogen and yet keep the reaction rates high. Reaction rates will be determined for various forms of lithium waste, from small chips to powder. Bench work will lead to the design of a skid-mounted process for treating wastes. Other water-reactive wastes will also be investigated.

Lussiez, G.W.

1993-05-01T23:59:59.000Z

255

Definition: Reactive Power | Open Energy Information  

Open Energy Info (EERE)

Reactive Power Reactive Power Jump to: navigation, search Dictionary.png Reactive Power The portion of electricity that establishes and sustains the electric and magnetic fields of alternating-current equipment. Reactive power must be supplied to most types of magnetic equipment, such as motors and transformers. It also must supply the reactive losses on transmission facilities. Reactive power is provided by generators, synchronous condensers, or electrostatic equipment such as capacitors and directly influences electric system voltage. It is usually expressed in kilovars (kvar) or megavars (Mvar).[1] View on Wikipedia Wikipedia Definition In electric power transmission and distribution, volt-ampere reactive (var) is a unit used to measure reactive power in an AC electric

256

Particle Swarm Optimization Based Reactive Power Optimization  

E-Print Network (OSTI)

Reactive power plays an important role in supporting the real power transfer by maintaining voltage stability and system reliability. It is a critical element for a transmission operator to ensure the reliability of an electric system while minimizing the cost associated with it. The traditional objectives of reactive power dispatch are focused on the technical side of reactive support such as minimization of transmission losses. Reactive power cost compensation to a generator is based on the incurred cost of its reactive power contribution less the cost of its obligation to support the active power delivery. In this paper an efficient Particle Swarm Optimization (PSO) based reactive power optimization approach is presented. The optimal reactive power dispatch problem is a nonlinear optimization problem with several constraints. The objective of the proposed PSO is to minimize the total support cost from generators and reactive compensators. It is achieved by maintaining the whole system power loss as minimum...

Sujin, P R; Linda, M Mary

2010-01-01T23:59:59.000Z

257

Engine combustion control via fuel reactivity stratification  

Science Conference Proceedings (OSTI)

A compression ignition engine uses two or more fuel charges having two or more reactivities to control the timing and duration of combustion. In a preferred implementation, a lower-reactivity fuel charge is injected or otherwise introduced into the combustion chamber, preferably sufficiently early that it becomes at least substantially homogeneously dispersed within the chamber before a subsequent injection is made. One or more subsequent injections of higher-reactivity fuel charges are then made, and these preferably distribute the higher-reactivity matter within the lower-reactivity chamber space such that combustion begins in the higher-reactivity regions, and with the lower-reactivity regions following thereafter. By appropriately choose the reactivities of the charges, their relative amounts, and their timing, combustion can be tailored to achieve optimal power output (and thus fuel efficiency), at controlled temperatures (and thus controlled NOx), and with controlled equivalence ratios (and thus controlled soot).

Reitz, Rolf Deneys; Hanson, Reed M; Splitter, Derek A; Kokjohn, Sage L

2013-12-31T23:59:59.000Z

258

Reactive and Catalytic Air Purification Materials - Energy ...  

Biomass and Biofuels; Building Energy Efficiency; Electricity Transmission; ... Target selectivity can be controlled through selection of reactive components.

259

Directional Reactive Power Ground Plane Transmission  

Directional Reactive Power Ground Plane Transmission Technology Summary ... The invention can transmit electrical power through the surface of the ...

260

Partnering Today: Technology Transfer Highlights Reactive ...  

THE LLNL TECHNOLOGY COMPANY PRODUCT Partnering Today: Technology Transfer Highlights Reactive NanoTechnologies Inc.: Temperature-controlled Precision Bonding

Note: This page contains sample records for the topic "multiphase reactive geochemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Gamma Survey of a Permeable Reactive Barrier at Monticello, Utah...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Gamma Survey of a Permeable Reactive Barrier at Monticello, Utah Gamma Survey of a Permeable Reactive Barrier at Monticello, Utah Gamma Survey of a Permeable Reactive Barrier at...

262

Trace Element Geochemical Zoning in the Roosevelt Hot Springs Thermal Area,  

Open Energy Info (EERE)

Page Page Edit with form History Facebook icon Twitter icon » Trace Element Geochemical Zoning in the Roosevelt Hot Springs Thermal Area, Utah Jump to: navigation, search OpenEI Reference LibraryAdd to library Conference Paper: Trace Element Geochemical Zoning in the Roosevelt Hot Springs Thermal Area, Utah Abstract Chemical interaction of thermal brines with reservoir rock in the Roosevelt Hot Springs thermal area has resulted in the development of distinctive trace element signatures. Geochemical analysis of soil sample, shallow temperature gradient drill hole cuttings and deep drill hole cutting provides a three dimensional perspective of trace element distributions within the system. Distributions of As, Hg and Li provide the clearest expression of hydrothermal activity. Comparison of these distribution

263

A Mineralogical Petrographic And Geochemical Study Of Samples From Wells In  

Open Energy Info (EERE)

Mineralogical Petrographic And Geochemical Study Of Samples From Wells In Mineralogical Petrographic And Geochemical Study Of Samples From Wells In The Geothermal Field Of Milos Island (Greece) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Mineralogical Petrographic And Geochemical Study Of Samples From Wells In The Geothermal Field Of Milos Island (Greece) Details Activities (0) Areas (0) Regions (0) Abstract: This paper presents a study of hydrothermal alteration on Milos island, Greece. Examination of cores and cuttings from the two drill sites, obtained from a depth of about 1100 m in Milos geothermal field, showed that the hydrothermal minerals occurring in the rock include: K-feldspar, albite, chlorite, talc, diopside, epidote, muscovite, tremolite, kaolinite, montmorillonite, alunite, anhydrite, gypsum, calcite, and opaque minerals.

264

Trace metal speciation in saline waters affected by geothermal brines. [GEOCHEM  

DOE Green Energy (OSTI)

A description is given of the chemical equilibrium computer program GEOCHEM, which has been developed to calculate trace element speciation in soil, irrigation, drainage, or Salton Sea waters affected by geothermal brine. GEOCHEM is applied to irrigation water-brine mixtures and to Salton Sea water-brine mixtures in order to compute the chemical speciation of the elements Cd, Cu, Hg, Ni, Pb, and Zn, along with the oxyanions of As and B. The results suggest that the computer simulation can have an important effect on a program for managing brine spills. Appendices include published papers on related research.

Sposito, G.; Page, A.L.

1977-11-01T23:59:59.000Z

265

Reactive transport modeling for CO2 geological sequestration  

E-Print Network (OSTI)

Geochemical detection of carbon dioxide in dilute aquifers.geological storage of carbon dioxide. Int. J. Greenhouse GasIPCC special report on carbon dioxide capture and storage.

Xu, T.

2013-01-01T23:59:59.000Z

266

Geochemical Journal, Vol. 39, pp. 383 to 389, 2005 *Corresponding author (e-mail: ytakaha@hiroshima-u.ac.jp)  

E-Print Network (OSTI)

383 Geochemical Journal, Vol. 39, pp. 383 to 389, 2005 *Corresponding author (e-mail: ytakaha@hiroshima,3 1 Department of Earth & Planetary Systems Science, Hiroshima University, Higashi-Hiroshima 739 for Multiple Isotope Research for Astro-and Geochemical Evolution (MIRAGE), Hiroshima University, Higashi-Hiroshima

267

GeoSys.Chem: Estimate of reservoir fluid characteristics as first step in geochemical modeling of geothermal systems  

Science Conference Proceedings (OSTI)

A computer code GeoSys.Chem for the calculation of deep geothermal reservoir fluid characteristics from the measured physical-chemical parameters of separated water and condensed vapor samples obtained from drilled wells is presented. It was written ... Keywords: GeoChem, GeoSys.Chem, Geochemical modeling, Los Azufres, VB.NET

Mahendra P. Verma

2012-12-01T23:59:59.000Z

268

Permeable Reactive Barriers | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Permeable Reactive Barriers Permeable Reactive Barriers Permeable Reactive Barriers Permeable Reactive Barrier Field Projects Durango, Colorado DOE installed a PRB in October 1995 to treat ground water from a uranium mill tailings disposal site at Durango, Colorado Read more Cañon City, Colorado ESL personnel conduct tests and help evaluate performance at other PRB sites, such as Cotter Corporation's Cañon City site in Colorado. Read more Monticello, Utah Installation of a PRB hydraulically downgradient of the Monticello, Utah, millsite was completed June 30, 1999, as an Interim Remedial Action. Read more A permeable reactive barrier (PRB) is a zone of reactive material placed underground to intercept and react with a contaminant plume in ground water. Typically, PRBs are emplaced by replacing soils with reactive

269

A coupled THC model of the FEBEX in situ test with bentonite swelling and chemical and thermal osmosis  

E-Print Network (OSTI)

of geological porous media with multiphase flow: theory andmultiphase flow and reactive transport in deformable porousisothermal multiphase flow and reactive transport in porous

Zheng, L.

2012-01-01T23:59:59.000Z

270

Comprehensive Approaches to Multiphase Flows in Geophysics - Application to nonisothermal, nonhomogenous, unsteady, large-scale, turbulent dusty clouds I. Hydrodynamic and Thermodynamic RANS and LES Models  

Science Conference Proceedings (OSTI)

The objective of this manuscript is to fully derive a geophysical multiphase model able to ''accommodate'' different multiphase turbulence approaches; viz., the Reynolds Averaged Navier-Stokes (RANS), the Large Eddy Simulation (LES), or hybrid RANSLES. This manuscript is the first part of a larger geophysical multiphase project--lead by LANL--that aims to develop comprehensive modeling tools for large-scale, atmospheric, transient-buoyancy dusty jets and plume (e.g., plinian clouds, nuclear ''mushrooms'', ''supercell'' forest fire plumes) and for boundary-dominated geophysical multiphase gravity currents (e.g., dusty surges, diluted pyroclastic flows, dusty gravity currents in street canyons). LES is a partially deterministic approach constructed on either a spatial- or a temporal-separation between the large and small scales of the flow, whereas RANS is an entirely probabilistic approach constructed on a statistical separation between an ensemble-averaged mean and higher-order statistical moments (the so-called ''fluctuating parts''). Within this specific multiphase context, both turbulence approaches are built up upon the same phasic binary-valued ''function of presence''. This function of presence formally describes the occurrence--or not--of any phase at a given position and time and, therefore, allows to derive the same basic multiphase Navier-Stokes model for either the RANS or the LES frameworks. The only differences between these turbulence frameworks are the closures for the various ''turbulence'' terms involving the unknown variables from the fluctuating (RANS) or from the subgrid (LES) parts. Even though the hydrodynamic and thermodynamic models for RANS and LES have the same set of Partial Differential Equations, the physical interpretations of these PDEs cannot be the same, i.e., RANS models an averaged field, while LES simulates a filtered field. In this manuscript, we also demonstrate that this multiphase model fully fulfills the second law of thermodynamics and fulfills the necessary requirements for a well-posed initial-value problem. In the next manuscripts, we will further develop specific closures for multiphase RANS, LES, and hybrid-LES.

S. Dartevelle

2005-09-05T23:59:59.000Z

271

Incorporation of Reaction Kinetics into a Multiphase, Hydrodynamic Model of a Fischer Tropsch Slurry Bubble Column Reactor  

DOE Green Energy (OSTI)

This paper describes the development of a computational multiphase fluid dynamics (CMFD) model of the Fischer Tropsch (FT) process in a Slurry Bubble Column Reactor (SBCR). The CMFD model is fundamentally based which allows it to be applied to different industrial processes and reactor geometries. The NPHASE CMFD solver [1] is used as the robust computational platform. Results from the CMFD model include gas distribution, species concentration profiles, and local temperatures within the SBCR. This type of model can provide valuable information for process design, operations and troubleshooting of FT plants. An ensemble-averaged, turbulent, multi-fluid solution algorithm for the multiphase, reacting flow with heat transfer was employed. Mechanistic models applicable to churn turbulent flow have been developed to provide a fundamentally based closure set for the equations. In this four-field model formulation, two of the fields are used to track the gas phase (i.e., small spherical and large slug/cap bubbles), and the other two fields are used for the liquid and catalyst particles. Reaction kinetics for a cobalt catalyst is based upon values reported in the published literature. An initial, reaction kinetics model has been developed and exercised to demonstrate viability of the overall solution scheme. The model will continue to be developed with improved physics added in stages.

Donna Guillen, PhD; Anastasia Gribik; Daniel Ginosar, PhD; Steven P. Antal, PhD

2008-11-01T23:59:59.000Z

272

Elucidating geochemical response of shallow heterogeneous aquifers to CO2 leakage using high-performance computing: Implications for monitoring of CO2 sequestration  

SciTech Connect

Predicting and quantifying impacts of potential carbon dioxide (CO2) leakage into shallow aquifers that overlie geologic CO2 storage formations is an important part of developing reliable carbon storage techniques. Leakage of CO2 through fractures, faults or faulty wellbores can reduce groundwater pH, inducing geochemical reactions that release solutes into the groundwater and pose a risk of degrading groundwater quality. In order to help quantify this risk, predictions of metal concentrations are needed during geologic storage of CO2. Here, we present regional-scale reactive transport simulations, at relatively fine-scale, of CO2 leakage into shallow aquifers run on the PFLOTRAN platform using high-performance computing. Multiple realizations of heterogeneous permeability distributions were generated using standard geostatistical methods. Increased statistical anisotropy of the permeability field resulted in more lateral and vertical spreading of the plume of impacted water, leading to increased Pb2+ (lead) concentrations and lower pH at a well down gradient of the CO2 leak. Pb2+ concentrations were higher in simulations where calcite was the source of Pb2+ compared to galena. The low solubility of galena effectively buffered the Pb2+ concentrations as galena reached saturation under reducing conditions along the flow path. In all cases, Pb2+ concentrations remained below the maximum contaminant level set by the EPA. Results from this study, compared to natural variability observed in aquifers, suggest that bicarbonate (HCO3) concentrations may be a better geochemical indicator of a CO2 leak under the conditions simulated here.

Navarre-Sitchler, Alexis K.; Maxwell, Reed M.; Siirila, Erica R.; Hammond, Glenn E.; Lichtner, Peter C.

2013-03-01T23:59:59.000Z

273

Chemie der Erde 65 (2005) 4778 Geochemical and isotopic characteristics and evolution of the  

E-Print Network (OSTI)

Chemie der Erde 65 (2005) 47­78 Geochemical and isotopic characteristics and evolution) and Pichowiak (1994). ARTICLE IN PRESS W. Kramer et al. / Chemie der Erde 65 (2005) 47­7848 #12;These east (Oficina Viz Fm.) on a wide front to the west (Caleta Ligate Fm.). W. Kramer et al. / Chemie der

Siebel, Wolfgang

274

Geochemical Implications of Gas Leakage Associated with Geologic CO2 Storage - A Qualitative Review  

SciTech Connect

Leakage from deep storage reservoirs is considered the major risk factor associated with geologic sequestration of CO2. Different schools of thought exist concerning the potential implications of such leakage for near-surface environments. We reviewed the current literature on how CO2 leakage (from storage reservoirs) would likely impact the geochemistry of overlying potable aquifers. Results from experimental and modeling studies point to the potential for both beneficial (e.g. contaminant immobilization) and deleterious (e.g. contaminant mobilization) consequences of CO2 intrusion into potable groundwater. However, there are significant discrepancies between studies particularly concerning, what contaminants are of concern and the geochemical processes involved. These discrepancies reflected the lack of a consensus on CO2-induced changes in subsurface geochemical processes and subsequent effects on groundwater chemistry. The development of consistent experimental protocols and the identification of pertinent factors driving CO2-induced geochemical changes in the subsurface were identified as key research needs. Geochemical modeling was used to systematically highlight why a standardization of experimental protocols and the consideration of experimental factors such as gas leakage rates, redox status and the influence of co-transported gases are pertinent. The role of analog studies, reactions occurring in the vadose zone, and the influence of organic contaminants are also discussed.

Harvey, Omar R.; Qafoku, Nikolla; Cantrell, Kirk J.; Lee, Gie Hyeon; Amonette, James E.; Brown, Christopher F.

2013-01-01T23:59:59.000Z

275

Geochemical constraints on the Palaeocene^ Miocene evolution of eastern Azerbaijan, with  

E-Print Network (OSTI)

Geochemical constraints on the Palaeocene^ Miocene evolution of eastern AzerbaijanEarth and Environmental Sciences, University of Texas at Arlington, Arlington,TX, USA zAzerbaijan NationalAcademy of Sciences Geology Institute ^ 29 A. H. Javid Pr., Baku, Azerbaijan ABSTRACT Fine-grained Palaeogene

Johnson, Cari

276

Geochemical modeling of the nuclear-waste repository system. A status report  

Science Conference Proceedings (OSTI)

The primary objective of the geochemical modeling task is to develop an understanding of the waste-repository geochemical system and provide a valuable tool for estimating future states of that system. There currently exists a variety of computer codes which can be used in geochemical modeling studies. Some available codes contain the framework for simulating a natural chemical system and estimating, within limits, the response of that system to environmental changes. By data-base enhancement and code development, this modeling technique can be even more usefully applied to a nuclear-waste repository. In particular, thermodynamic data on elements not presently in the data base but identified as being of particular hazard in the waste-repository system, need to be incorporated into the code to estimate the near-field as well as the far-field reactions during a hypothetical breach. A reaction-path-simulation code, which estimates the products of specific rock/water reactions, has been tested using basalt and ground water. Results show that the mass-transfer capabilities of the code will be useful in chemical-evolution studies and scenario analyses. The purpose of this report is to explain the status of geochemical modeling as it currently applies to the chemical system of a hypothetical nuclear-waste repository in basalt and to present the plan proposed for further developmet and application.

Deutsch, W.J.

1980-12-01T23:59:59.000Z

277

Geochemical anomalies in soil and sandstone overlying the Phoenix uranium deposit, Athabasca Basin Natural Resources  

E-Print Network (OSTI)

Collaboration Introduction The Wheeler River Property, host of Denison Mine's Phoenix uranium depositCo Mo Ni UU Geochemical anomalies in soil and sandstone overlying the Phoenix uranium deposit is the most efficient analytical method to detect these anomalies. Athabasca Basin Figure 1: Denison Mine

278

Soil geochemical survey over concealed kimberlites in the Attawapiskat area in northern Canada  

E-Print Network (OSTI)

lengths of 562 m over the Whiskey kimberlite and 740 m over the Yankee kimberlite pipe. B-horizon soil of the kimberlite pipes. Ammonium acetate leach at pH 5 (AA5) dissolves most of these carbonates, and shows geochemical characteristics of kimberlites in com- parison with peridotites, oceanic basalts (MORB

279

Z .Chemical Geology 145 1998 153159 z /Geochemical Earth Reference Model GERM  

E-Print Network (OSTI)

Z .Chemical Geology 145 1998 153­159 z /Geochemical Earth Reference Model GERM : description on a chemical characterization of the Earth, its major reservoirs, and the fluxes between them. The Z .GERM chemical Z . Z .reservoirs of the present-day Earth, from core to atmosphere; 2 present-day fluxes between

Mcdonough, William F.

280

Paper #194973 GEOCHEMICAL CHARACTERIZATION OF THE RESERVOIR HOSTING SHALE-GAS AND OIL in  

E-Print Network (OSTI)

Paper #194973 GEOCHEMICAL CHARACTERIZATION OF THE RESERVOIR HOSTING SHALE-GAS AND OIL a reservoir for shale-gas and oil. We examined organic-rich black shale, known as Macasty shale, of Upper SHALE-GAS AND OIL in THE SUBSURFACE OF ANTICOSTI ISLAND, CANADA Key Words: Provenance, Anticosti Island

Note: This page contains sample records for the topic "multiphase reactive geochemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Oak Ridge Geochemical Reconnaissance Program. [For National Uranium Resource Evaluation Program  

SciTech Connect

The Oak Ridge reconnaissance program is responsible for the geochemical survey in a 12-state area covering Texas, Oklahoma, Kansas, Nebraska, South Dakota, North Dakota, Minnesota, Wisconsin, Michigan, Iowa, Indiana, and Illinois as part of the National Uranium Resource Evaluation Program. The program concept is outlined and the planning and organization of the program is discussed. (JSR)

Arendt, J.W.

1977-03-01T23:59:59.000Z

282

Reactive Transport and Coupled THM Processes in Engineering Barrier Systems (EBS)  

E-Print Network (OSTI)

Sorption of Long-Lived Radionuclides Cesium-134, Strontium-term retardation of radionuclide release. EBS is involved inas heat release due to radionuclide decay, multiphase flow (

Steefel, Carl

2010-01-01T23:59:59.000Z

283

Geochemical Characterization of Chromate Contamination in the 100 Area Vadose Zone at the Hanford Site  

SciTech Connect

The major objectives of the proposed study were to: 1.) determine the leaching characteristics of hexavalent chromium [Cr(VI)] from contaminated sediments collected from 100 Area spill sites; 2.) elucidate possible Cr(VI) mineral and/or chemical associations that may be responsible for Cr(VI) retention in the Hanford Site 100 Areas through the use of i.) macroscopic leaching studies and ii.) microscale characterization of contaminated sediments; and 3.) provide information to construct a conceptual model of Cr(VI) geochemistry in the Hanford 100 Area vadose zone. In addressing these objectives, additional benefits accrued were: (1) a fuller understanding of Cr(VI) entrained in the vadose zone that will that can be utilized in modeling potential Cr(VI) source terms, and (2) accelerating the Columbia River 100 Area corridor cleanup by providing valuable information to develop remedial action based on a fundamental understanding of Cr(VI) vadose zone geochemistry. A series of macroscopic column experiments were conducted with contaminated and uncontaminated sediments to study Cr(VI) desorption patterns in aged and freshly contaminated sediments, evaluate the transport characteristics of dichromate liquid retrieved from old pipelines of the 100 Area; and estimate the effect of strongly reducing liquid on the reduction and transport of Cr(VI). Column experiments used the < 2 mm fraction of the sediment samples and simulated Hanford groundwater solution. Periodic stop-flow events were applied to evaluate the change in elemental concentration during time periods of no flow and greater fluid residence time. The results were fit using a two-site, one dimensional reactive transport model. Sediments were characterized for the spatial and mineralogical associations of the contamination using an array of microscale techniques such as XRD, SEM, EDS, XPS, XMP, and XANES. The following are important conclusions and implications. Results from column experiments indicated that most of contaminant Cr travels fast through the sediments and appears as Cr(VI) in the effluents. The significance of this for groundwater concentrations would, however, depend on the mass flux of recharge to the water table. adsorption of Cr(VI) to sediments from spiked Cr(VI) solution is low; calculated retardation coefficients are close to one. Calcium polysulfide solutions readily reduced Cr(VI) to Cr(III) in column experiments. However a significant amount of the Cr(VI) was mobilized ahead of the polysulfide solution front. This has significant implications for in-situ reductive remediation techniques. The experiments suggest that it would be difficult to design a remedial measure using infiltration of liquid phase reductants without increasing transport of Cr(VI) toward the water table. The microscopic characterization results are consistent with the column studies. Cr(VI) is found as ubiquitous coatings on sediment grain surfaces. Small, higher concentration, chromium sites are associated with secondary clay mineral inclusions, with occasional barium chromate minerals, and reduced to Cr(III) in association with iron oxides that are most likely magnetite primary minerals. Within the restricted access domains of sediment matrix, ferrous iron could also diffuse from in situ, high-surface-area minerals to cause the reductive immobilization of chromate. This process may be favored at microscale geochemical zones where ferrous iron could be supplied. Once nucleated, micrometer-scale precipitates are favored as growing locales for further accumulation, causing the formation of discrete zones of Cr(III).

Dresel, P. Evan; Qafoku, Nikolla; McKinley, James P.; Fruchter, Jonathan S.; Ainsworth, Calvin C.; Liu, Chongxuan; Ilton, Eugene S.; Phillips, J. L.

2008-07-16T23:59:59.000Z

284

Soil Iodine Determination in Deccan Syneclise, India: Implications for Near Surface Geochemical Hydrocarbon Prospecting  

Science Conference Proceedings (OSTI)

The association of iodine with organic matter in sedimentary basins is well documented. High iodine concentration in soils overlying oil and gas fields and areas with hydrocarbon microseepage has been observed and used as a geochemical exploratory tool for hydrocarbons in a few studies. In this study, we measure iodine concentration in soil samples collected from parts of Deccan Syneclise in the west central India to investigate its potential application as a geochemical indicator for hydrocarbons. The Deccan Syneclise consists of rifted depositional sites with Gondwana-Mesozoic sediments up to 3.5 km concealed under the Deccan Traps and is considered prospective for hydrocarbons. The concentration of iodine in soil samples is determined using ICP-MS and the values range between 1.1 and 19.3 ppm. High iodine values are characteristic of the northern part of the sampled region. The total organic carbon (TOC) content of the soil samples range between 0.1 and 1.3%. The TOC correlates poorly with the soil iodine (r{sup 2} propane-oxidizing bacterial populations in the soil. The integration of geochemical observations show the occurrence of elevated values in the northern part of the study area, which is also coincident with the presence of exposed dyke swarms that probably serve as conduits for hydrocarbon microseepage. The corroboration of iodine with existing geological, geophysical, and geochemical data suggests its efficacy as one of the potential tool in surface geochemical exploration of hydrocarbons. Our study supports Deccan Syneclise to be promising in terms of its hydrocarbon prospects.

Mani, Devleena, E-mail: devleenatiwari@ngri.res.in [National Geophysical Research Institute (Council of Scientific and Industrial Research) (India); Kumar, T. Satish [Oil India Limited (India); Rasheed, M. A.; Patil, D. J.; Dayal, A. M.; Rao, T. Gnaneshwar; Balaram, V. [National Geophysical Research Institute (Council of Scientific and Industrial Research) (India)

2011-03-15T23:59:59.000Z

285

Benchmarks for Quantifying Fuel Reactivity Depletion Uncertainty  

Science Conference Proceedings (OSTI)

Analytical methods, described in this report, are used to systematically determine experimental fuel sub-batch reactivities as a function of burnup. Fuel sub-batch reactivities are inferred using more than 600 in-core pressurized water reactor (PWR) flux maps taken during 44 cycles of operation at the Catawba and McGuire nuclear power plants. The analytical methods systematically search for fuel sub-batch reactivities that minimize differences between measured and computed reaction rates, using Studsvik ...

2011-08-08T23:59:59.000Z

286

Rejuvenating Permeable Reactive Barriers by Chemical Flushing  

Energy.gov (U.S. Department of Energy (DOE))

Final Report:Rejuvenating Permeable Reactive Barriers by Chemical Flushing,U.S. Environmental Protection Agency, Region 8 Support.August 2004

287

ENGINE COMBUSTION CONTROL VIA FUEL REACTIVITY ...  

A compression ignition engine uses two or more fuel charges having two or more reactivities to control the timing and duration of combustion. In a ...

288

Electrochemistry of Enargite: Reactivity in Alkaline Solutions  

Science Conference Proceedings (OSTI)

The reactivity of enargite samples from Montana, US and Quiruvilca, Peru were studied under alkaline conditions, pH range of 8-13, using a cyclic voltammetry ...

289

Reactive Air Aluminizing - Energy Innovation Portal  

Reactive Air Aluminizing is a process for applying a protective coating on steel components in solid oxide fuel ... Building Energy Efficiency; ...

290

Reactive Air Aluminizing - Energy Innovation Portal  

Reactive Air Aluminizing is a process for applying a protective coating on steel components in solid oxide fuel cells and other high temperature electrochemical devices.

291

Device and method for measuring multi-phase fluid flow in a conduit having an abrupt gradual bend  

DOE Patents (OSTI)

A system is described for measuring fluid flow in a conduit having an abrupt bend. The system includes pressure transducers, one disposed in the conduit at the inside of the bend and one or more disposed in the conduit at the outside of the bend but spaced a distance therefrom. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow. 1 fig.

Ortiz, M.G.

1998-02-10T23:59:59.000Z

292

Theoretical and experimental analysis of a multiphase screw pump, handling gas-liquid mixtures with very high gas volume fractions  

SciTech Connect

In the investigation of the pumping behaviour of multiphase screw pumps, handling gas-liquid mixtures with very high gas volume fractions, theoretical and experimental analyses were performed. A new theoretical screw pump model was developed, which calculates the time-dependent conditions inside the several chambers of a screw pump as well as the exchange of mass and energy between these chambers. By means of the performed experimental analysis, the screw pump model was verified, especially at very high gas volume fractions from 90% to 99%. The experiments, which were conducted with the reference fluids water and air, can be divided mainly into the determination of the steady state pumping behaviour on the one hand and into the analysis of selected transient operating conditions on the other hand, whereas the visualisation of the leakage flows through the circumferential gaps was rounded off the experimental analysis. (author)

Raebiger, K. [LEISTRITZ Pumpen GmbH, Nuremberg (Germany); Faculty of Advanced Technology, University of Glamorgan, Pontypridd, Wales (United Kingdom); Maksoud, T.M.A.; Ward, J. [Faculty of Advanced Technology, University of Glamorgan, Pontypridd, Wales (United Kingdom); Hausmann, G. [Department of Mechanical Engineering and Building Services Engineering, University of Applied Sciences, Nuremberg (Germany)

2008-09-15T23:59:59.000Z

293

Proceedings: Fossil Plant Layup and Reactivation Conference  

Science Conference Proceedings (OSTI)

In recent years, the layup and reactivation of fossil-fired power plants has become more important as increasing numbers of utilities develop a need for retaining capacity not currently needed. A 1992 EPRI conference highlighted key technical issues, focusing on proven layup procedures, descriptions of layup equipment and preservation methods, layup and reactivation case studies, and summaries of regulatory issues.

1992-10-01T23:59:59.000Z

294

Geochemical Aspects of the Carbonation of Magnesium Silicates in an Aqueous Medium  

NLE Websites -- All DOE Office Websites (Extended Search)

GEOCHEMICAL ASPECTS OF THE CARBONATION OF MAGNESIUM GEOCHEMICAL ASPECTS OF THE CARBONATION OF MAGNESIUM SILICATES IN AN AQUEOUS MEDIUM George D. Guthrie, Jr. (gguthrie@lanl.gov 505-665-6340) J. William Carey (bcarey@lanl.gov 505-667-5540) Deborah Bergfeld (debberrg@lanl.gov 505-667-1812) Darrin Byler (dbyler@lanl.gov 505-665-9562) Steve Chipera (chipera@lanl.gov 505-667-1110) Hans-Joachim Ziock (ziock@lanl.gov 505-667-7265) Hydrology, Geochemistry, & Geology Los Alamos National Laboratory Los Alamos, NM 87545 Klaus Lackner (ksl@lanl.gov 505-667-5694) Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM and Columbia University, New York, NY KEYWORDS: CO 2 sequestration, magnesium silicate, mineral carbonation INTRODUCTION The volume of carbon dioxide associated with the use of fossil fuels to produce

295

Field-based tests of geochemical modeling codes using New Zealand hydrothermal systems  

DOE Green Energy (OSTI)

Hydrothermal systems in the Taupo Volcanic Zone, North Island, New Zealand are being used as field-based modeling exercises for the EQ3/6 geochemical modeling code package. Comparisons of the observed state and evolution of the hydrothermal systems with predictions of fluid-solid equilibria made using geochemical modeling codes will determine how the codes can be used to predict the chemical and mineralogical response of the environment to nuclear waste emplacement. Field-based exercises allow us to test the models on time scales unattainable in the laboratory. Preliminary predictions of mineral assemblages in equilibrium with fluids sampled from wells in the Wairakei and Kawerau geothermal field suggest that affinity-temperature diagrams must be used in conjunction with EQ6 to minimize the effect of uncertainties in thermodynamic and kinetic data on code predictions.

Bruton, C.J.; Glassley, W.E.; Bourcier, W.L.

1994-06-01T23:59:59.000Z

296

Origin of geochemical heterogeneity in the mantle : constraints from volcanism associated with Hawaiian and Kerguelen mantle plumes  

E-Print Network (OSTI)

Lavas derived from long-lived mantle plumes provide important information of mantle compositions and the processes that created the geochemical heterogeneity within the mantle. Kerguelen and Hawaii are two long-lived mantle ...

Xu, Guangping

2007-01-01T23:59:59.000Z

297

Evaluation of selected geochemical anomalies in Colorado and the Southeastern US. Final report  

SciTech Connect

This study demonstrates the utility of HSSR geochemical data from stream sediment in exploration for uranium. In the southeastern US, four uraniferous occurrences and associated radiometric anomalies were identified in areas where uranium mineralization has not been previously reported. At two localities, assays of about .01% have been obtained from saprolite. There is some evidence which suggests that uranium may have been leached at these localities and that higher grades of U are likely at depth.

Carpenter, R H

1980-08-01T23:59:59.000Z

298

Proceedings of the second workshop on hydrologic and geochemical monitoring in the Long Valley Caldera  

DOE Green Energy (OSTI)

A workshop was held to review the results of hydrologic and geochemical monitoring and scientific drilling in the Long Valley caldera. Such monitoring is being done to detect changes in the hydrothermal system induced by ongoing magmatic and techonic processes. Data from a 2400-ft deep core hole completed in June 1986 were presented at the 1986 workshop and participants discussed the need and rationale for siting locations for future scientific drilling in the caldera.

Sorey, M.L.; Farrar, C.D.; Wollenberg, H.A. (eds.)

1986-12-01T23:59:59.000Z

299

Simulations of highly reactive fluids  

SciTech Connect

We report density functional molecular dynamics simulations to determine the early chemical events of hot (T = 3000 K) and dense (1.97 g/cm{sup 3}, V/V{sub 0} = 0.68) nitromethane (CH{sub 3}NO{sub 2}). The first step in the decomposition process is an intermolecular proton abstraction mechanism that leads to the formation of CH{sub 3}NO{sub 2}H and the aci ion H{sub 2}CNO{sub 2}{sup -}, in support of evidence from static high-pressure and shock experiments. An intramolecular hydrogen transfer that transforms nitromethane into the aci acid form, CH{sub 2}NO{sub 2}H, accompanies this event. This is the first confirmation of chemical reactivity with bond selectivity for an energetic material near the condition of fully reacted specimen. We also report the decomposition mechanism followed up to the formation of H{sub 2}O as the first stable product.

Fried, L E; Manaa, M R; Reed, E J

2005-07-21T23:59:59.000Z

300

Reactive Power Measurement Using the Wavelet Transform  

E-Print Network (OSTI)

Abstract—This paper provides the theoretical basis for the measurement of reactive and distortion powers from the wavelet transforms. The measurement of reactive power relies on the use of broad-band phase-shift networks to create concurrent in-phase currents and quadrature voltages. The wavelet real power computation resulting from these 90 phase-shift networks yields the reactive power associated with each wavelet frequency level or subband. The distortion power at each wavelet subband is then derived from the real, reactive and apparent powers of the subband, where the apparent power is the product of the v; i element pair's subband rms voltage and current. The advantage of viewing the real and reactive powers in the wavelet domain is that the domain preserves both the frequency and time relationship of these powers. In addition, the reactive power associated with each wavelet subband is a signed quantity and thus has a direction associated with it. This permits tracking the reactive power flow in each subband through the power system. Index Terms—Digital signal processing, phase shift networks, measurement, power, RMS, subband, wavelets. I.

Weon-ki Yoon; Michael J. Devaney

2000-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "multiphase reactive geochemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Comparison of biomass and coal char reactivities  

SciTech Connect

Char combustion is typically the rate limiting step during the combustion of solid fuels. The magnitude and variation of char reactivity during combustion are, therefore, of primary concern when comparing solid fuels such as coal and biomass. In an effort to evaluate biomass` potential as a sustainable and renewable energy source, the reactivities of both biomass and coal chars were compared using Sandia`s Captive Particle Imaging (CPI) apparatus. This paper summarizes the experimental approach used to determine biomass and coal reactivities and presents results from CPT experiments. The reactivity of six types of char particles, two high-rank coal chars, two low-rank coal chars, and two biomass chars, were investigated using the CPT apparatus. Results indicate that both of the high-rank coal chars have relatively low reactivities when compared with the higher reactivities measured for the low-rank coal and the biomass chars. In addition, extinction behavior of the chars support related investigations that suggest carbonaceous structural ordering is an important consideration in understanding particle reactivity as a function of extent of burnout. High-rank coal chars were found to have highly ordered carbon structures, where as, both low-rank coal and biomass chars were found to have highly disordered carbon structures.

Huey, S.P. [Sandia National Labs., Livermore, CA (United States); Davis, K.A. [Reaction Engineering International, Salt Lake City, UT (United States); Hurt, R.H. [Brown Univ., Providence, RI (United States). Div. of Engineering

1995-08-01T23:59:59.000Z

302

Geochemical Data Package for Performance Assessment Calculations Related to the Savannah River Site  

Science Conference Proceedings (OSTI)

The Savannah River Site disposes of certain types of radioactive waste within subsurface-engineered facilities. One of the tools used to establish the capacity of a given site to safely store radioactive waste (i.e., that a site does not exceed its Waste Acceptance Criteria) is the Performance Assessment (PA). The objective of this document is to provide the geochemical values for the PA calculations. This work is being conducted as part of the on-going maintenance program that permits the PA to periodically update existing calculations when new data becomes available. Because application of values without full understanding of their original purpose may lead to misuse, this document also provides the geochemical conceptual model, approach used for selecting the values, the justification for selecting data, and the assumptions made to assure that the conceptual and numerical geochemical models are reasonably conservative (i.e., reflect conditions that will tend to predict the maximum risk to the hypothetical recipient). The geochemical parameters describe transport processes for 38 elements (>90 radioisotopes) potentially occurring within eight disposal units (Slit Trenches, Engineered Trenches, Low Activity Waste (LAW) Vault, Intermediate Level (ILV) Vaults, TRU-Pad-1, Naval Reactor Waste Pads, Components-in-Grout Trenches, and Saltstone Facility). This work builds upon well-documented work from previous PA calculations (McDowell-Boyer et al. 2000). The new geochemical concepts introduced in this data package are: (1) In the past, solubility products were used only in a few conditions (element existing in a specific environmental setting). This has been expanded to >100 conditions. (2) Radionuclide chemistry in cementitious environments is described through the use of both the Kd and apparent solubility concentration limit. Furthermore, the solid phase is assumed to age during the assessment period (thousands of years), resulting in three main types of controlling solid phases, each possessing a unique set of radionuclide sorption parameters (Kd and solubility concentration limit). (3) A large amount of recent site-specific sorption research has been conducted since the last PA (McDowell-Boyer et al. 2000). These new data have replaced previous Kd values derived from literature values, thus reducing uncertainty and improving accuracy. Finally, because this document will be used by future PA calculations and external acceptance of the document will eventually be required, this document was extensively reviewed. The review process, including the internal review, site review, and external review process is described.

Kaplan, D

2006-02-28T23:59:59.000Z

303

Systematic approach for chemical reactivity evaluation  

E-Print Network (OSTI)

Under certain conditions, reactive chemicals may proceed into uncontrolled chemical reaction pathways with rapid and significant increases in temperature, pressure, and/or gas evolution. Reactive chemicals have been involved in many industrial incidents, and have harmed people, property, and the environment. Evaluation of reactive chemical hazards is critical to design and operate safer chemical plant processes. Much effort is needed for experimental techniques, mainly calorimetric analysis, to measure thermal reactivity of chemical systems. Studying all the various reaction pathways experimentally however is very expensive and time consuming. Therefore, it is essential to employ simplified screening tools and other methods to reduce the number of experiments and to identify the most energetic pathways. A systematic approach is presented for the evaluation of reactive chemical hazards. This approach is based on a combination of computational methods, correlations, and experimental thermal analysis techniques. The presented approach will help to focus the experimental work to the most hazardous reaction scenarios with a better understanding of the reactive system chemistry. Computational methods are used to predict reaction stoichiometries, thermodynamics, and kinetics, which then are used to exclude thermodynamically infeasible and non-hazardous reaction pathways. Computational methods included: (1) molecular group contribution methods, (2) computational quantum chemistry methods, and (3) correlations based on thermodynamic-energy relationships. The experimental techniques are used to evaluate the most energetic systems for more accurate thermodynamic and kinetics parameters, or to replace inadequate numerical methods. The Reactive System Screening Tool (RSST) and the Automatic Pressure Tracking Adiabatic Calorimeter (APTAC) were employed to evaluate the reactive systems experimentally. The RSST detected exothermic behavior and measured the overall liberated energy. The APTAC simulated near-adiabatic runaway scenarios for more accurate thermodynamic and kinetic parameters. The validity of this approach was investigated through the evaluation of potentially hazardous reactive systems, including decomposition of di-tert-butyl peroxide, copolymerization of styrene-acrylonitrile, and polymerization of 1,3-butadiene.

Aldeeb, Abdulrehman Ahmed

2003-12-01T23:59:59.000Z

304

Theoretical and Experimental Evaluation of Chemical Reactivity  

E-Print Network (OSTI)

Reactive chemicals are presented widely in the chemical and petrochemical process industry. Their chemical reactivity hazards have posed a significant challenge to the industries of manufacturing, storage and transportation. The accidents due to reactive chemicals have caused tremendous loss of properties and lives, and damages to the environment. In this research, three classes of reactive chemicals (unsaturated hydrocarbons, self-reacting chemicals, energetic materials) were evaluated through theoretical and experimental methods. Methylcyclopentadiene (MCP) and Hydroxylamine (HA) are selected as representatives of unsaturated hydrocarbons and self-reacting chemicals, respectively. Chemical reactivity of MCP, including isomerization, dimerization, and oxidation, is investigated by computational chemistry methods and empirical thermodynamic–energy correlation. Density functional and ab initio methods are used to search the initial thermal decomposition steps of HA, including unimolecular and bimolecular pathways. In addition, solvent effects are also examined using water cluster methods and Polarizable Continuum Models (PCM) for aqueous solution of HA. The thermal stability of a basic energetic material, Nitroethane, is investigated through both theoretical and experimental methods. Density functional methods are employed to explore the initial decomposition pathways, followed by developing detailed reaction networks. Experiments with a batch reactor and in situ GC are designed to analyze the distribution of reaction products and verify reaction mechanisms. Overall kinetic model is also built from calorimetric experiments using an Automated Pressure Tracking Adiabatic Calorimeter (APTAC). Finally, a general evaluation approach is developed for a wide range of reactive chemicals. An index of thermal risk is proposed as a preliminary risk assessment to screen reactive chemicals. Correlations are also developed between reactivity parameters, such as onset temperature, activation energy, and adiabatic time to maximum rate based on a limited number, 37 sets, of Differential Scanning Calorimeter (DSC) data. The research shows broad applications in developing reaction mechanisms at the molecular level. The methodology of reaction modeling in combination with molecular modeling can also be used to study other reactive chemical systems.

Wang, Qingsheng

2010-08-01T23:59:59.000Z

305

COAL SLAGGING AND REACTIVITY TESTING  

SciTech Connect

Union Fenosa's La Robla I Power Station is a 270-MW Foster Wheeler arch-fired system. The unit is located at the mine that provides a portion of the semianthracitic coal. The remaining coals used are from South Africa, Russia, Australia, and China. The challenges at the La Robla I Station stem from the various fuels used, the characteristics of which differ from the design coal. The University of North Dakota Energy & Environmental Research Center (EERC) and the Lehigh University Energy Research Center (LUERC) undertook a program to assess problematic slagging and unburned carbon issues occurring at the plant. Full-scale combustion tests were performed under baseline conditions, with elevated oxygen level and with redistribution of air during a site visit at the plant. During these tests, operating information, observations and temperature measurements, and coal, slag deposit, and fly ash samples were obtained to assess slagging and unburned carbon. The slagging in almost all cases appeared due to elevated temperatures rather than fuel chemistry. The most severe slagging occurred when the temperature at the sampling port was in excess of 1500 C, with problematic slagging where first-observed temperatures exceeded 1350 C. The presence of anorthite crystals in the bulk of the deposits analyzed indicates that the temperatures were in excess of 1350 C, consistent with temperature measurements during the sampling period. Elevated temperatures and ''hot spots'' are probably the result of poor mill performance, and a poor distribution of the coal from the mills to the specific burners causes elevated temperatures in the regions where the slag samples were extracted. A contributing cause appeared to be poor combustion air mixing and heating, resulting in oxygen stratification and increased temperatures in certain areas. Air preheater plugging was observed and reduces the temperature of the air in the windbox, which leads to poor combustion conditions, resulting in unburned carbon as well as slagging. A second phase of the project involved advanced analysis of the baseline coal along with an Australian coal fired at the plant. These analysis results were used in equilibrium thermodynamic modeling along with a coal quality model developed by the EERC to assess slagging, fouling, and opacity for the coals. Bench-scale carbon conversion testing was performed in a drop-tube furnace to assess the reactivity of the coals. The Australian coal had a higher mineral content with significantly more clay minerals present than the baseline coal. The presence of these clay minerals, which tend to melt at relatively low temperatures, indicated a higher potential for problematic slagging than the baseline coal. However, the pyritic minerals, comprising over 25% of the baseline mineral content, may form sticky iron sulfides, leading to severe slagging in the burner region if local areas with reducing conditions exist. Modeling results indicated that neither would present significant fouling problems. The Australian coal was expected to show slagging behavior much more severe than the baseline coal except at very high furnace temperatures. However, the baseline coal was predicted to exhibit opacity problems, as well as have a higher potential for problematic calcium sulfate-based low-temperature fouling. The baseline coal had a somewhat higher reactivity than the Australian coal, which was consistent with both the lower average activation energy for the baseline coal and the greater carbon conversion at a given temperature and residence time. The activation energy of the baseline coal showed some effect of oxygen on the activation energy, with E{sub a} increasing at the lower oxygen concentration, but may be due to the scatter in the baseline coal kinetic values at the higher oxygen level tested.

Donald P. McCollor; Kurt E. Eylands; Jason D. Laumb

2003-10-01T23:59:59.000Z

306

Final Report Phase II: Performance Evaluation of Permeable Reactive  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Final Report Phase II: Performance Evaluation of Permeable Reactive Final Report Phase II: Performance Evaluation of Permeable Reactive Barriers and Potential for Rejuvenation by Chemical Flushing Final Report Phase II: Performance Evaluation of Permeable Reactive Barriers and Potential for Rejuvenation by Chemical Flushing Final Report Phase II: Performance Evaluation of Permeable Reactive Barriers and Potential for Rejuvenation by Chemical Flushing Final Report Phase II: Performance Evaluation of Permeable Reactive Barriers and Potential for Rejuvenation by Chemical Flushing More Documents & Publications Phase II: Performance Evaluation of Permeable Reactive Barriers and Potential for Rejuvenation by Chemical Flushing Rejuvenating Permeable Reactive Barriers by Chemical Flushing Final Report - Rejuvenating Permeable Reactive Barriers by Chemical

307

Hydraulic Conductivity of the Monticello Permeable Reactive Barrier  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Hydraulic Conductivity of the Monticello Permeable Reactive Barrier Hydraulic Conductivity of the Monticello Permeable Reactive Barrier November 2005 Update Hydraulic Conductivity of the Monticello Permeable Reactive Barrier November 2005 Update Hydraulic Conductivity of the Monticello Permeable Reactive Barrier November 2005 Update Hydraulic Conductivity of the Monticello Permeable Reactive Barrier November 2005 Update More Documents & Publications Variation in Hydraulic Conductivity Over Time at the Monticello Permeable Reactive Barrier Performance Assessment and Recommendations for Rejuvenation of a Permeable Reactive Barrier: Cotter Corporation's Cañon City, Colorado, Uranium Mill Performance Assessment and Recommendations for Rejuvenation of a Permeable Reactive Barrier: Cotter Corporation's Cañon City, Colorado, Uranium

308

Efficient and Reliable Reactive Power Supply and Consumption...  

NLE Websites -- All DOE Office Websites (Extended Search)

Efficient and Reliable Reactive Power Supply and Consumption - Insights from an Integrated Program of Engineering and Economics Research Title Efficient and Reliable Reactive Power...

309

Olefin production via reactive distillation based Olefin metathesis.  

E-Print Network (OSTI)

??Reactive distillation is a combination of a traditional multi-stage distillation column with a chemical reaction. The primary benefits of a reactive distillation process are reduced… (more)

Morrison, Ryan Frederick

2012-01-01T23:59:59.000Z

310

A Parametric Reactive Distillation Study: Economic Feasibility and Design Heuristics.  

E-Print Network (OSTI)

??The integration of reaction and distillation into a single column is called reactive distillation or catalytic distillation. Reactive distillation provides many benefits such as reduced… (more)

Hoyme, Craig Alan

2004-01-01T23:59:59.000Z

311

Observations on the Coke Air Reactivity Test - Programmaster.org  

Science Conference Proceedings (OSTI)

Coke air reactivities are strongly dependent on coke calcination levels and it is possible to drive air reactivities lower by increasing calcining temperatures.

312

Reactivity control assembly for nuclear reactor  

DOE Patents (OSTI)

Reactivity control assembly for nuclear reactor comprises supports stacked above reactor core for holding control rods. Couplers associated with the supports and a vertically movable drive shaft have lugs at their lower ends for engagement with the supports.

Bollinger, Lawrence R. (Schenectady, NY)

1984-01-01T23:59:59.000Z

313

A Tariff for Reactive Power - IEEE  

DOE Green Energy (OSTI)

This paper describes a suggested tariff or payment for the local supply of reactive power from distributed energy resources. The authors consider four sample customers, and estimate the cost of supply of reactive power for each customer. The power system savings from the local supply of reactive power are also estimated for a hypothetical circuit. It is found that reactive power for local voltage regulation could be supplied to the distribution system economically by customers when new inverters are installed. The inverter would be supplied with a power factor of 0.8, and would be capable of local voltage regulation to a schedule supplied by the utility. Inverters are now installed with photovoltaic systems, fuel cells and microturbines, and adjustable-speed motor drives.

Kueck, John D [ORNL; Tufon, Christopher [Pacific Gas and Electric Company; Isemonger, Alan [California Independent System Operator; Kirby, Brendan J [ORNL

2008-11-01T23:59:59.000Z

314

Mild coal pretreatment to improve liquefaction reactivity  

SciTech Connect

This report describes work completed during the fourth quarter of a three year project to study the effects of mild chemical pretreatment on coal dissolution reactivity during low severity liquefaction or coal/oil coprocessing. The overall objective of this research is to elucidate changes in the chemical and physical structure of coal by pretreating with methanol or other simple organic solvent and a trace amount of hydrochloric acid and measure the influence of these changes on coal dissolution reactivity. This work is part of a larger effort to develop a new coal liquefaction or coal/oil coprocessing scheme consisting of three main process steps: (1) mile pretreatment of the feed coal to enhance dissolution reactivity and dry the coal, (2) low severity thermal dissolution of the pretreated coal to obtain a very reactive coal-derived residual material amenable to upgrading, and (3) catalytic upgrading of the residual products to distillate liquids.

Miller, R.L.

1991-01-01T23:59:59.000Z

315

Groundwater well with reactive filter pack  

DOE Patents (OSTI)

A method and apparatus for the remediation of contaminated soil and ground water wherein a reactive pack material is added to the annular fill material utilized in standard well construction techniques.

Gilmore, Tyler J. (Pasco, WA); Holdren, Jr., George R. (Kennewick, WA); Kaplan, Daniel I. (Richland, WA)

1998-01-01T23:59:59.000Z

316

Fossil plant layup and reactivation conference: Proceedings  

Science Conference Proceedings (OSTI)

The Fossil Plant Layup and Reactivation Conference was held in New Orleans, Louisiana on April 14--15, 1992. The Conference was sponsored by EPRI and hosted by Entergy Services, Inc. to bring together representatives from utilities, consulting firms, manufacturers and architectural engineers. Eighteen papers were presented in three sessions. These sessions were devoted to layup procedures and practices, and reactivation case studies. A panel discussion was held on the second day to interactively discuss layup and reactivation issues. More than 80 people attended the Conference. This report contains technical papers and a summary of the panel discussion. Of the eighteen papers, three are related to general, one is related to regulatory issues, three are related to specific equipment, four are related to layup procedures and practices, and seven are layup and reactivation case studies.

Not Available

1992-10-01T23:59:59.000Z

317

Oxidation Resistance of Reactive Atoms in Graphene  

SciTech Connect

We have found that reactive elements that are normally oxidized at room temperature are present as individual atoms or clusters on and in graphene. Oxygen is present in these samples but it is only detected in the thicker amorphous carbon layers present in the graphene specimens we have examined. However, we have seen no evidence that oxygen reacts with the impurity atoms and small clusters of these normally reactive elements when they are incorporated in the graphene layers. First principles calculations suggest that the oxidation resistance is due to kinetic effects such as preferential bonding of oxygen to nonincorporated atoms and H passivation. The observed oxidation resistance of reactive atoms in graphene may allow the use of these incorporated metals in catalytic applications. It also opens the possibility of designing and producing electronic, opto-electronic, and magnetic devices based on these normally reactive atoms.

Chisholm, Matthew F [ORNL; Duscher, Gerd [University of Tennessee, Knoxville (UTK); Windl, Wolfgang [Ohio State University

2012-01-01T23:59:59.000Z

318

Radiative Forcing Due to Reactive Gas Emissions  

Science Conference Proceedings (OSTI)

Reactive gas emissions (CO, NOx, VOC) have indirect radiative forcing effects through their influences on tropospheric ozone and on the lifetimes of methane and hydrogenated halocarbons. These effects are quantified here for the full set of ...

T. M. L. Wigley; S. J. Smith; M. J. Prather

2002-09-01T23:59:59.000Z

319

INVESTIGATION OF MULTISCALE AND MULTIPHASE FLOW, TRANSPORT AND REACTION IN HEAVY OIL RECOVERY PROCESSES  

Science Conference Proceedings (OSTI)

This is final report for contract DE-AC26-99BC15211. The report describes progress made in the various thrust areas of the project, which include internal drives for oil recovery, vapor-liquid flows, combustion and reaction processes and the flow of fluids with yield stress. The report consists mainly of a compilation of various topical reports, technical papers and research reports published produced during the three-year project, which ended on May 6, 2002 and was no-cost extended to January 5, 2003. Advances in multiple processes and at various scales are described. In the area of internal drives, significant research accomplishments were made in the modeling of gas-phase growth driven by mass transfer, as in solution-gas drive, and by heat transfer, as in internal steam drives. In the area of vapor-liquid flows, we studied various aspects of concurrent and countercurrent flows, including stability analyses of vapor-liquid counterflow, and the development of novel methods for the pore-network modeling of the mobilization of trapped phases and liquid-vapor phase changes. In the area of combustion, we developed new methods for the modeling of these processes at the continuum and pore-network scales. These models allow us to understand a number of important aspects of in-situ combustion, including steady-state front propagation, multiple steady-states, effects of heterogeneity and modes of combustion (forward or reverse). Additional aspects of reactive transport in porous media were also studied. Finally, significant advances were made in the flow and displacement of non-Newtonian fluids with Bingham plastic rheology, which is characteristic of various heavy oil processes. Various accomplishments in generic displacements in porous media and corresponding effects of reservoir heterogeneity are also cited.

Yannis C. Yortsos

2003-02-01T23:59:59.000Z

320

Final Report Coupling in silico microbial models with reactive transport models to predict the fate of contaminants in the subsurface.  

Science Conference Proceedings (OSTI)

This project successfully accomplished its goal of coupling genome-scale metabolic models with hydrological and geochemical models to predict the activity of subsurface microorganisms during uranium bioremediation. Furthermore, it was demonstrated how this modeling approach can be used to develop new strategies to optimize bioremediation. The approach of coupling genome-scale metabolic models with reactive transport modeling is now well enough established that it has been adopted by other DOE investigators studying uranium bioremediation. Furthermore, the basic principles developed during our studies will be applicable to much broader investigations of microbial activities, not only for other types of bioremediation, but microbial metabolism in diversity of environments. This approach has the potential to make an important contribution to predicting the impact of environmental perturbations on the cycling of carbon and other biogeochemical cycles.

Lovley, Derek R.

2012-10-31T23:59:59.000Z

Note: This page contains sample records for the topic "multiphase reactive geochemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Three-dimensional multiphase segmentation of X-ray CT data of porous materials using a Bayesian Markov random field framework  

SciTech Connect

Advancements in noninvasive imaging methods such as X-ray computed tomography (CT) have led to a recent surge of applications in porous media research with objectives ranging from theoretical aspects of pore-scale fluid and interfacial dynamics to practical applications such as enhanced oil recovery and advanced contaminant remediation. While substantial efforts and resources have been devoted to advance CT technology, microscale analysis, and fluid dynamics simulations, the development of efficient and stable three-dimensional multiphase image segmentation methods applicable to large data sets is lacking. To eliminate the need for wet-dry or dual-energy scans, image alignment, and subtraction analysis, commonly applied in X-ray micro-CT, a segmentation method based on a Bayesian Markov random field (MRF) framework amenable to true three-dimensional multiphase processing was developed and evaluated. Furthermore, several heuristic and deterministic combinatorial optimization schemes required to solve the labeling problem of the MRF image model were implemented and tested for computational efficiency and their impact on segmentation results. Test results for three grayscale data sets consisting of dry glass beads, partially saturated glass beads, and partially saturated crushed tuff obtained with synchrotron X-ray micro-CT demonstrate great potential of the MRF image model for three-dimensional multiphase segmentation. While our results are promising and the developed algorithm is stable and computationally more efficient than other commonly applied porous media segmentation models, further potential improvements exist for fully automated operation.

Kulkarni, Ramaprasad; Tuller, Markus; Fink, Wolfgang; Wildschild, Dorthe (Oregon State U.); (Ariz)

2012-07-27T23:59:59.000Z

322

Enhanced Oxidative Reactivity for Anthracite Coal via a Reactive Ball Milling Pretreatment Step  

Science Conference Proceedings (OSTI)

Reactive ball milling in a cyclohexene solvent significantly increases the oxidative reactivity of an anthracite coal, due to the combined effects of particle size reduction, metal introduction, introduction of volatile matter, and changes in carbon structure. Metals introduced during milling can be easily removed via a subsequent demineralization process, and the increased reactivity is retained. Solvent addition alters the morphological changes that occur during pyrolysis and leads to a char with significantly increased reactivity. When the solvent is omitted, similar effects are seen for the milled product, but a significant fraction of the char is resistant to oxidation. 33 refs., 3 figs., 1 tab.

Angela D. Lueking; Apurba Sakti; Dania Alvarez-Fonseca; Nichole Wonderling [Pennsylvania State University, PA (United States). Department of Energy and Mineral Engineering

2009-09-15T23:59:59.000Z

323

Variably Saturated Flow and Multicomponent Biogeochemical Reactive Transport Modeling of a Uranium Bioremediation Field Experiment  

Science Conference Proceedings (OSTI)

Field experiments at a former uranium mill tailings site have identified the potential for stimulating indigenous bacteria to catalyze the conversion of aqueous uranium in the +6 oxidation state to immobile solid-associated uranium in the +4 oxidation state. This effectively removes uranium from solution resulting in groundwater concentrations below actionable standards. Three-dimensional, coupled variably-saturated flow and biogeochemical reactive transport modeling of a 2008 in situ uranium bioremediation field experiment is used to better understand the interplay of transport rates and biogeochemical reaction rates that determine the location and magnitude of key reaction products. A comprehensive reaction network, developed largely through previous 1-D modeling studies, was used to simulate the impacts on uranium behavior of pulsed acetate amendment, seasonal water table variation, spatially-variable physical (hydraulic conductivity, porosity) and geochemical (reactive surface area) material properties. A principal challenge is the mechanistic representation of biologically-mediated terminal electron acceptor process (TEAP) reactions whose products significantly alter geochemical controls on uranium mobility through increases in pH, alkalinity, exchangeable cations, and highly reactive reduction products. In general, these simulations of the 2008 Big Rusty acetate biostimulation field experiment in Rifle, Colorado confirmed previously identified behaviors including (1) initial dominance by iron reducing bacteria that concomitantly reduce aqueous U(VI), (2) sulfate reducing bacteria that become dominant after {approx}30 days and outcompete iron reducers for the acetate electron donor, (3) continuing iron-reducer activity and U(VI) bioreduction during dominantly sulfate reducing conditions, and (4) lower apparent U(VI) removal from groundwater during dominantly sulfate reducing conditions. New knowledge on simultaneously active metal and sulfate reducers has been incorporated into the modeling. In this case, an initially small population of slow growing sulfate reducers is active from the initiation of biostimulation. Three-dimensional, variably saturated flow modeling was used to address impacts of a falling water table during acetate injection. These impacts included a significant reduction in aquifer saturated thickness and isolation of residual reactants and products, as well as unmitigated uranium, in the newly unsaturated vadose zone. High permeability sandy gravel structures resulted in locally high flow rates in the vicinity of injection wells that increased acetate dilution. In downgradient locations, these structures created preferential flow paths for acetate delivery that enhanced local zones of TEAP reactivity and subsidiary reactions. Conversely, smaller transport rates associated with the lower permeability lithofacies (e.g., fine) and vadose zone were shown to limit acetate access and reaction. Once accessed by acetate, however, these same zones limited subsequent acetate dilution and provided longer residence times that resulted in higher concentrations of TEAP products when terminal electron donors and acceptors were not limiting. Finally, facies-based porosity and reactive surface area variations were shown to affect aqueous uranium concentration distributions; however, the ranges were sufficiently small to preserve general trends. Large computer memory and high computational performance were required to simulate the detailed coupled process models for multiple biogeochemical components in highly resolved heterogeneous materials for the 110-day field experiment and 50 days of post-biostimulation behavior. In this case, a highly-scalable subsurface simulator operating on 128 processor cores for 12 hours was used to simulate each realization. An equivalent simulation without parallel processing would have taken 60 days, assuming sufficient memory was available.

Yabusaki, Steven B.; Fang, Yilin; Williams, Kenneth H.; Murray, Christopher J.; Ward, Anderson L.; Dayvault, Richard; Waichler, Scott R.; Newcomer, Darrell R.; Spane, Frank A.; Long, Philip E.

2011-11-01T23:59:59.000Z

324

Data for the geochemical investigation of UMTRAP designated site at Ambrosia Lake, New Mexico  

SciTech Connect

This report contains the geochemical data and the methods of data collection from the former tailings site at Ambrosia Lake, New Mexico. Data are from a one-time sampling of waters and solid material from the background, the area adjacent to the site, and the site. Selected solid samples are water extracted to remove easily soluble salts and acid extracted to remove carbonates and hydroxides. The waters, extracts, and solid samples were analyzed for selected major and trace elements. 3 refs., 2 figs., 1 tab.

Markos, G.; Bush, K.J.

1983-09-01T23:59:59.000Z

325

review of extraction, processing, properties & applications of reactive ...  

Science Conference Proceedings (OSTI)

REVIEW OF EXTRACTION,. PROCESSING, PROPERTIES. & APPLICATIONS OF. REACTIVE METALS. Edited by. Brajendra Mishra ...

326

Final Report Phase II: Performance Evaluation of Permeable Reactive  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Final Report Phase II: Performance Evaluation of Permeable Reactive Final Report Phase II: Performance Evaluation of Permeable Reactive Barriers and Potential for Rejuvenation by Chemical Flushing Final Report Phase II: Performance Evaluation of Permeable Reactive Barriers and Potential for Rejuvenation by Chemical Flushing Final Report Phase II: Performance Evaluation of Permeable Reactive Barriers and Potential for Rejuvenation by Chemical Flushing Final Report Phase II: Performance Evaluation of Permeable Reactive Barriers and Potential for Rejuvenation by Chemical Flushing More Documents & Publications Phase II: Performance Evaluation of Permeable Reactive Barriers and Potential for Rejuvenation by Chemical Flushing Final Report - Rejuvenating Permeable Reactive Barriers by Chemical Flushing, U.S. Environmental Protection Agency Region 8 Support

327

Phase II: Performance Evaluation of Permeable Reactive Barriers and  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Phase II: Performance Evaluation of Permeable Reactive Barriers and Phase II: Performance Evaluation of Permeable Reactive Barriers and Potential for Rejuvenation by Chemical Flushing Phase II: Performance Evaluation of Permeable Reactive Barriers and Potential for Rejuvenation by Chemical Flushing Final Report Phase II: Performance Evaluation of Permeable Reactive Barriers and Potential for Rejuvenation by Chemical Flushing U. S. Environmental Protection Agency Region 8 Support January 2004 Phase II: Performance Evaluation of Permeable Reactive Barriers and Potential for Rejuvenation by Chemical Flushing More Documents & Publications Final Report Phase II: Performance Evaluation of Permeable Reactive Barriers and Potential for Rejuvenation by Chemical Flushing Rejuvenating Permeable Reactive Barriers by Chemical Flushing

328

Hydraulic Conductivity of the Monticello Permeable Reactive Barrier  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Hydraulic Conductivity of the Monticello Permeable Reactive Barrier Hydraulic Conductivity of the Monticello Permeable Reactive Barrier November 2005 Update Hydraulic Conductivity of the Monticello Permeable Reactive Barrier November 2005 Update Hydraulic Conductivity of the Monticello Permeable Reactive Barrier November 2005 Update Hydraulic Conductivity of the Monticello Permeable Reactive Barrier November 2005 Update More Documents & Publications Variation in Hydraulic Conductivity Over Time at the Monticello Permeable Reactive Barrier Ground-Water Table and Chemical Changes in an Alluvial Aquifer During Sustained Pumping at the Monticello, Utah, Zero-Valent Iron Treatment Cells Performance Assessment and Recommendations for Rejuvenation of a Permeable Reactive Barrier: Cotter Corporation's Cañon City, Colorado, Uranium

329

Transport Modeling of Reactive and Non-Reactive Constituents from Summitville,  

E-Print Network (OSTI)

Survey (USGS) began water- quality investigations at Summitville, Terrace #12;Figure 2. Aerial photographTransport Modeling of Reactive and Non- Reactive Constituents from Summitville, Colorado in the Wightman Fork/Alamosa River system downstream of the Summitville Mine, south-central Colorado, were

330

Geochemical Implications of CO2 Leakage Associated with Geologic Storage: A Review  

SciTech Connect

Leakage from deep storage reservoirs is a major risk factor associated with geologic sequestration of carbon dioxide (CO2). Different scientific theories exist concerning the potential implications of such leakage for near-surface environments. The authors of this report reviewed the current literature on how CO2 leakage (from storage reservoirs) would likely impact the geochemistry of near surface environments such as potable water aquifers and the vadose zone. Experimental and modeling studies highlighted the potential for both beneficial (e.g., CO2 re sequestration or contaminant immobilization) and deleterious (e.g., contaminant mobilization) consequences of CO2 intrusion in these systems. Current knowledge gaps, including the role of CO2-induced changes in redox conditions, the influence of CO2 influx rate, gas composition, organic matter content and microorganisms are discussed in terms of their potential influence on pertinent geochemical processes and the potential for beneficial or deleterious outcomes. Geochemical modeling was used to systematically highlight why closing these knowledge gaps are pivotal. A framework for studying and assessing consequences associated with each factor is also presented in Section 5.6.

Harvey, Omar R.; Qafoku, Nikolla; Cantrell, Kirk J.; Brown, Christopher F.

2012-07-09T23:59:59.000Z

331

Trace metal speciation in saline waters affected by geothermal brines. Final technical report. [GEOCHEM  

DOE Green Energy (OSTI)

The computer program GEOCHEM was developed and applied to calculate the speciation of trace elements, such as Li, B, Mn, Co, Ni, Cu, Zn, Pb, and As, in mixtures of geothermal brines with soil waters. A typical speciation calculation involved the simultaneous consideration of about 350 inorganic and organic complexes and about 80 possible solid phases that could form among the macro- and microconstituents in the mixtures. The four geothermal brines chosen for study were from the East Mesa, Heber, and Salton Sea KGRA's. Two examples of East Mesa brine were employed in order to illustrate the effect of brine variability within a given KGRA. The soil waters chosen for study were the Holtville, Rosita, and Vint soil solutions and the Vail 4 drain water. These waters were mixed with the four brines to produce 1%, 5%, and 10% brine combinations. The combinations then were analyzed with the help of GEOCHEM and were interpreted in the context of two proposed general contamination scenarios. The results of the speciation calculations pointed to the great importance, in brine, of sulfide as a precipitating agent for trace metals and of borate as a trace metal-complexing ligand. In general, precipitation and/or exchange adsorption in soil were found to reduce the levels of trace metals well below harmful concentrations. The principal exceptions were Li and B, which did not precipitate and which were at or very hear harmful levels in the soil water-brine mixtures.

Sposito, G.

1979-07-01T23:59:59.000Z

332

Nuclear engine flow reactivity shim control  

DOE Patents (OSTI)

A nuclear engine control system is provided which automatically compensates for reactor reactivity uncertainties at the start of life and reactivity losses due to core corrosion during the reactor life in gas-cooled reactors. The coolant gas flow is varied automatically by means of specially provided control apparatus so that the reactor control drums maintain a predetermined steady state position throughout the reactor life. This permits the reactor to be designed for a constant drum position and results in a desirable, relatively flat temperature profile across the core. (Official Gazette)

Walsh, J.M.

1973-12-11T23:59:59.000Z

333

A sequential partly iterative approach for multicomponent reactive transport with CORE2D  

SciTech Connect

CORE{sup 2D} V4 is a finite element code for modeling partly or fully saturated water flow, heat transport and multicomponent reactive solute transport under both local chemical equilibrium and kinetic conditions. It can handle coupled microbial processes and geochemical reactions such as acid-base, aqueous complexation, redox, mineral dissolution/precipitation, gas dissolution/exsolution, ion exchange, sorption via linear and nonlinear isotherms, sorption via surface complexation. Hydraulic parameters may change due to mineral precipitation/dissolution reactions. Coupled transport and chemical equations are solved by using sequential iterative approaches. A sequential partly-iterative approach (SPIA) is presented which improves the accuracy of the traditional sequential noniterative approach (SNIA) and is more efficient than the general sequential iterative approach (SIA). While SNIA leads to a substantial saving of computing time, it introduces numerical errors which are especially large for cation exchange reactions. SPIA improves the efficiency of SIA because the iteration between transport and chemical equations is only performed in nodes with a large mass transfer between solid and liquid phases. The efficiency and accuracy of SPIA are compared to those of SIA and SNIA using synthetic examples and a case study of reactive transport through the Llobregat Delta aquitard in Spain. SPIA is found to be as accurate as SIA while requiring significantly less CPU time. In addition, SPIA is much more accurate than SNIA with only a minor increase in computing time. A further enhancement of the efficiency of SPIA is achieved by improving the efficiency of the Newton-Raphson method used for solving chemical equations. Such an improvement is obtained by working with increments of log-concentrations and ignoring the terms of the Jacobian matrix containing derivatives of activity coefficients. A proof is given for the symmetry and non-singularity of the Jacobian matrix. Numerical analyses performed with synthetic examples confirm that these modifications improve the efficiency and convergence of the iterative algorithm.

Samper, J.; Xu, T.; Yang, C.

2008-11-01T23:59:59.000Z

334

Neutron Radiography Reactor Reactivity -- Focused Lessons Learned  

SciTech Connect

As part of the Global Threat Reduction Initiative, the Neutron Radiography Reactor (NRAD) at the Idaho National Laboratory (INL) was converted from using highly enriched uranium (HEU) to low enriched uranium (LEU) fuel. After the conversion, NRAD resumed operations and is meeting operational requirements. Radiography image quality and the number of images that can be produced in a given time frame match pre-conversion capabilities. However, following the conversion, NRAD’s excess reactivity with the LEU fuel was less than it had been with the HEU fuel. Although some differences between model predictions and actual performance are to be expected, the lack of flexibility in NRAD’s safety documentation prevented adjusting the reactivity by adding more fuel, until the safety documentation could be modified. To aid future reactor conversions, a reactivity-focused Lessons Learned meeting was held. This report summarizes the findings of the lessons learned meeting and addresses specific questions posed by DOE regarding NRAD’s conversion and reactivity.

Eric Woolstenhulme; Randal Damiana; Kenneth Schreck; Ann Marie Phillips; Dana Hewit

2010-11-01T23:59:59.000Z

335

LES algorithm for turbulent reactive flows simulation  

Science Conference Proceedings (OSTI)

The paper presents the development and implementation of a Large Eddy Simulation numerical algorithm for simulating turbulent reactive flows. The numerical algorithm is based on a 5 step modified Runge - Kutta numerical scheme with a dual time stepping ... Keywords: Runge - Kutta numerical scheme, large eddy simulation, linear eddy model

Ionut Porumbel; Cristian Cârl?nescu; Florin Gabriel Florean; Constantin Eusebiu Hritcu

2010-10-01T23:59:59.000Z

336

Investigation of the Effect of Non-Darcy Flow and Multi-Phase Flow on the Productivity of Hydraulically Fractured Gas Wells  

E-Print Network (OSTI)

Hydraulic fracturing has recently been the completion of choice for most tight gas bearing formations. It has proven successful to produce these formations in a commercial manner. However, some considerations have to be taken into account to design an optimum stimulation treatment that leads to the maximum possible productivity. These considerations include, but not limited to, non-Darcy flow and multiphase flow effects inside the fracture. These effects reduce the fracture conductivity significantly. Failing to account for that results in overestimating the deliverability of the well and, consequently, to designing a fracture treatment that is not optimum. In this work a thorough investigation of non-Darcy flow and multi-phase flow effects on the productivity of hydraulically fractured wells is conducted and an optimum fracture design is proposed for a tight gas formation in south Texas using the Unified Fracture Design (UFD) Technique to compensate for the mentioned effects by calculating the effective fracture permeability in an iterative way. Incorporating non-Darcy effects results in an optimum fracture that is shorter and wider than the fracture when only Darcy calculations are considered. That leads to a loss of production of 5, 18 percent due to dry and multiphase non-Darcy flow effects respectively. A comparison between the UFD and 3D simulators is also done to point out the differences in terms of methodology and results. Since UFD incorporated the maximum dimensionless productivity index in the fracture dimensions design, unlike 3D simulators, it can be concluded that using UFD to design the fracture treatment and then use the most important fracture parameters outputs (half length and CfDopt) as inputs in the simulators is a recommended approach.

Alarbi, Nasraldin Abdulslam A.

2011-08-01T23:59:59.000Z

337

Numerical Modeling of Coupled Variably-Saturated Fluid Flow and Reactive Transport with Fast and Slow Chemical Reactions  

SciTech Connect

The couplings among chemical reaction rates, advective and diffusive transport in fractured media or soils, and changes in hydraulic properties due to precipitation and dissolution within fractures and in rock matrix are important for both nuclear waste disposal and remediation of contaminated sites. This paper describes the development and application of LEHGC2.0, a mechanistically-based numerical model for simulation of coupled fluid flow and reactive chemical transport including both fast and slow reactions invariably saturated media. Theoretical bases and numerical implementations are summarized, and two example problems are demonstrated. The first example deals with the effect of precipitation-dissolution on fluid flow and matrix diffusion in a two-dimensional fractured media. Because of the precipitation and decreased diffusion of solute from the fracture into the matrix, retardation in the fractured medium is not as large as the case wherein interactions between chemical reactions and transport are not considered. The second example focuses on a complicated but realistic advective-dispersive-reactive transport problem. This example exemplifies the need for innovative numerical algorithms to solve problems involving stiff geochemical reactions.

LI, MING-HSU; SIEGEL, MALCOLM D.; YEH, GOUR-TSYH (GEORGE)

1999-09-20T23:59:59.000Z

338

Geological, geochemical, and geophysical survey of the geothermal resources at Hot Springs Bay Valley, Akutan Island, Alaska  

DOE Green Energy (OSTI)

An extensive survey was conducted of the geothermal resource potential of Hot Springs Bay Valley on Akutan Island. A topographic base map was constructed, geologic mapping, geophysical and geochemical surveys were conducted, and the thermal waters and fumarolic gases were analyzed for major and minor element species and stable isotope composition. (ACR)

Motyka, R.J.; Wescott, E.M.; Turner, D.L.; Swanson, S.E.; Romick, J.D.; Moorman, M.A.; Poreda, R.J.; Witte, W.; Petzinger, B.; Allely, R.D.

1985-01-01T23:59:59.000Z

339

Geochemical records in the South China Sea: implications for East Asian summer monsoon evolution over the last 20 Ma  

E-Print Network (OSTI)

Geochemical records in the South China Sea: implications for East Asian summer monsoon evolution past changes in the East Asian summer monsoon over the last 20 Ma using samples from Ocean Drilling and combined review suggests that the long-term evolution of the East Asian summer monsoon is similar

Clift, Peter

340

Geochemical Data on Waters, gases, scales, and rocks from the Dixie Valley Region, Nevada (1996-1999)  

DOE Green Energy (OSTI)

This report tabulates an extensive geochemical database on waters, gases, scales, rocks, and hot-spring deposits from the Dixie Valley region, Nevada. The samples from which the data were obtained were collected and analyzed during 1996 to 1999. These data provide useful information for ongoing and future investigations on geothermal energy, volcanism, ore deposits, environmental issues, and groundwater quality in this region.

Goff, Fraser; Bergfeld, Deborah; Janik, C.J.; et al

2002-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "multiphase reactive geochemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

VOLTINT: A Matlab®-based program for semi-automated processing of geochemical data acquired by voltammetry  

Science Conference Proceedings (OSTI)

Recent progress has resulted in the development of advanced techniques to acquire geochemical information in situ in aquatic systems. Among these techniques, voltammetry has generated significant interest for its ability to detect several important redox-sensitive ... Keywords: Data processing, Geochemistry, Integration, Matlab®, Software, Voltammetry

Gwendolyn Bristow; Martial Taillefert

2008-02-01T23:59:59.000Z

342

Method for generating a highly reactive plasma for exhaust gas after treatment and enhanced catalyst reactivity  

DOE Patents (OSTI)

This patent application describes a method and apparatus of exhaust gas remediation that enhance the reactivity of the material catalysts found within catalytic converters of cars, trucks, and power stations.

Whealton, John H.; Hanson, Gregory R.; Storey, John M.; Raridon, Richard J.; Armfield, Jeffrey S.; Bigelow, Timothy S.; Graves, Ronald L.

2000-07-01T23:59:59.000Z

343

Workshop on hydrologic and geochemical monitoring in the Long Valley Caldera: proceedings  

DOE Green Energy (OSTI)

A workshop reviewed the results of hydrologic and geochemical monitoring in the Long Valley caldera. Such monitoring is being done to detect changes in the hydrothermal system induced by ongoing magmatic and tectonic processes. Workshop participants discussed the need to instrument sites for continuous measurements of several parameters and to obtain additional hydrologic and chemical information from intermediate and deep drill holes. In addition to seismic and deformation monitoring, programs are currently in progress to monitor changes in the discharge characteristics of hot springs, fumaroles, and soil gases, as well as pressures and temperatures in wells. Some hydrochemical parameters are measured continuously, others are measured monthly or at longer intervals. This report summarizes the information presented at the hydrologic monitoring workshop, following the workshop agenda which was divided into four sessions: (1) overview of the hydrothermal system; (2) monitoring springs, fumaroles, and wells; (3) monitoring gas emissions; and (4) conclusions and recommendations.

Sorey, M.L.; Farrar, C.D.; Wollenberg, H.A.

1984-10-01T23:59:59.000Z

344

Geochemical and physical properties of wetland soils at the Savannah River site  

Science Conference Proceedings (OSTI)

The Savannah River Site (SRS), located in Aiken, Allendale, and Barnwell Counties, South Carolina, is a nuclear production facility operated for the U.S. Department of Energy (DOE) by Westinghouse Savannah River Company (WSRC). To facilitate future human health and ecological risk assessments, treatability studies, remedial investigations, and feasibility studies for its wetland areas, SRS needs a database of background geochemical and physical properties of wetland soils. These data are needed for comparison to data collected from wetland soils that may have been affected by SRS operations. SRS contains 36,000 acres of wetlands and an additional 5,000 acres of bottom land soils subject to flooding. Recent studies of wetland soils near various waste units at SRS show that some wetlands have been impacted by releases of contaminants resulting from SRS operations (WSRC, 1992). Waste waters originating from the operations facilities typically have been discharged into seepage basins located in upland soils, direct discharge of waste water to wetland areas has been minimal. This suggests that impacted wetland areas have been affected indirectly as a result of transport mechanisms such as surface runoff, groundwater seeps, fluvial or sediment transport, and leaching. Looney et al. (1990) conducted a study to characterize the geochemical and physical properties of upland soils and shallow sediments on the SRS. A primary objective of the upland study was to collect the data needed to assess the qualitative and quantitative impacts of SRS operations on the environment. By comparing the upland soils data to data collected from waste units located in similar soils, SRS impacts could be assessed. The data were also intended to aid in selection of remediation alternatives. Because waste units at SRS have historically been located in upland areas, wetland soils were not sampled. (Abstract Truncated)

Dixon, K.L; Rogers, V.A.; Conner, S.P.; Cummings, C.L.; Gladden, J.B.; Weber, J.M.

1996-05-01T23:59:59.000Z

345

Hydrogeochemical and stream sediment detailed geochemical survey for Edgemont, South Dakota; Wyoming  

SciTech Connect

Results of the Edgemont detailed geochemical survey are reported. Field and laboratory data are presented for 109 groundwater and 419 stream sediment samples. Statistical and areal distributions of uranium and possible uranium-related variables are given. A generalized geologic map of the survey area is provided, and pertinent geologic factors which may be of significance in evaluating the potential for uranium mineralization are briefly discussed. Groundwaters containing greater than or equal to 7.35 ppB uranium are present in scattered clusters throughout the area sampled. Most of these groundwaters are from wells drilled where the Inyan Kara Group is exposed at the surface. The exceptions are a group of samples in the northwestern part of the area sampled and south of the Dewey Terrace. These groundwaters are also produced from the Inyan Kara Group where it is overlain by the Graneros Group and alluvium. The high uranium groundwaters along and to the south of the terrace are characterized by high molybdenum, uranium/specific conductance, and uranium/sulfate values. Many of the groundwaters sampled along the outcrop of the Inyan Kara Group are near uranium mines. Groundwaters have high amounts of uranium and molybdenum. Samples taken downdip are sulfide waters with low values of uranium and high values of arsenic, molybdenum, selenium, and vanadium. Stream sediments containing greater than or equal to 5.50 ppM soluble uranium are concentrated in basins draining the Graneros and Inyan Kara Groups. These values are associated with high values for arsenic, selenium, and vanadium in samples from both groups. Anomalous values for these elements in the Graneros Group may be caused by bentonite beds contained in the rock units. As shown on the geochemical distribution plot, high uranium values that are located in the Inyan Kara Group are almost exclusively draining open-pit uranium mines.

Butz, T.R.; Dean, N.E.; Bard, C.S.; Helgerson, R.N.; Grimes, J.G.; Pritz, P.M.

1980-05-31T23:59:59.000Z

346

ENVIRONMENTAL REACTIVITY OF SOLID STATE HYDRIDE MATERIALS  

DOE Green Energy (OSTI)

In searching for high gravimetric and volumetric density hydrogen storage systems, it is inevitable that higher energy density materials will be used. In order to make safe and commercially acceptable condensed phase hydrogen storage systems, it is important to understand quantitatively the risks involved in using and handling these materials and to develop appropriate mitigation strategies to handle potential material exposure events. A crucial aspect of the development of risk identification and mitigation strategies is the development of rigorous environmental reactivity testing standards and procedures. This will allow for the identification of potential risks and implementation of risk mitigation strategies. Modified testing procedures for shipping air and/or water sensitive materials, as codified by the United Nations, have been used to evaluate two potential hydrogen storage materials, 2LiBH{sub 4} {center_dot} MgH{sub 2} and NH{sub 3}BH{sub 3}. The modified U.N. procedures include identification of self-reactive substances, pyrophoric substances, and gas-emitting substances with water contact. The results of these tests for air and water contact sensitivity will be compared to the pure material components where appropriate (e.g. LiBH{sub 4} and MgH{sub 2}). The water contact tests are divided into two scenarios dependent on the hydride to water mole ratio and heat transport characteristics. Air contact tests were run to determine whether a substance will spontaneously react with air in a packed or dispersed form. In the case of the 2LiBH{sub 4} {center_dot} MgH{sub 2} material, the results from the hydride mixture compared to the pure materials results showed the MgH{sub 2} to be the least reactive component and LiBH{sub 4} the more reactive. The combined 2LiBH{sub 4} {center_dot} MgH{sub 2} resulted in a material having environmental reactivity between these two materials. Relative to 2LiBH{sub 4} {center_dot} MgH{sub 2}, the chemical hydride NH{sub 3}BH{sub 3} was observed to be less environmentally reactive.

Gray, J; Donald Anton, D

2009-04-23T23:59:59.000Z

347

Behavior of Laminate Reactive Materials under Dynamic Loading ...  

Science Conference Proceedings (OSTI)

Presentation Title, Behavior of Laminate Reactive Materials under Dynamic Loading ... Atomistically-Informed Dislocation Dynamics Simulations of High Rate  ...

348

SIC Manufature via Reactive Infiltration - Programmaster.org  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, Materials Science & Technology 2013. Symposium, Ceramic Matrix Composites. Presentation Title, SIC Manufature via Reactive ...

349

Multiple Steady States in Azeotropic and Reactive Distillation  

E-Print Network (OSTI)

Introduction . Motivation Overview on the Contributions MSS in Reactive Distillation Conclusions Outline Multiple Steady States (MSS) Overview on the Contributions . The Starting Point . Consolidation . Industrial Applications . Incorporating Reactions MSS in Reactive Distillation Conclusions Outline Multiple Steady States (MSS) Overview on the Contributions MSS in Reactive Distillation . Prediction Method . MTBE Process Conclusions Outline Multiple Steady States (MSS) Overview on the Contributions MSS in Reactive Distillation Conclusions Distillation Overview . Ideal binary / multicomponent distillation . Homogeneous azeotropic distillation -- Heavy entrainer (extractive distillation) -- Intermediate entrainer -- "Boundary scheme" (ligh

Thomas E. Güttinger

1998-01-01T23:59:59.000Z

350

Image analysis algorithms for estimating porous media multiphase flow variables from computed microtomography data: a validation study  

Science Conference Proceedings (OSTI)

Image analysis of three-dimensional microtomographic image data has become an integral component of pore scale investigations of multiphase flow through porous media. This study focuses on the validation of image analysis algorithms for identifying phases and estimating porosity, saturation, solid surface area, and interfacial area between fluid phases from gray-scale X-ray microtomographic image data. The data used in this study consisted of (1) a two-phase high precision bead pack from which porosity and solid surface area estimates were obtained and (2) three-phase cylindrical capillary tubes of three different radii, each containing an air-water interface, from which interfacial area was estimated. The image analysis algorithm employed here combines an anisotropic diffusion filter to remove noise from the original gray-scale image data, a k-means cluster analysis to obtain segmented data, and the construction of isosurfaces to estimate solid surface area and interfacial area. Our method was compared with laboratory measurements, as well as estimates obtained from a number of other image analysis algorithms presented in the literature. Porosity estimates for the two-phase bead pack were within 1.5% error of laboratory measurements and agreed well with estimates obtained using an indicator kriging segmentation algorithm. Additionally, our method estimated the solid surface area of the high precision beads within 10% of the laboratory measurements, whereas solid surface area estimates obtained from voxel counting and two-point correlation functions overestimated the surface area by 20--40%. Interfacial area estimates for the air-water menisci contained within the capillary tubes were obtained using our image analysis algorithm, and using other image analysis algorithms, including voxel counting, two-point correlation functions, and the porous media marching cubes. Our image analysis algorithm, and other algorithms based on marching cubes, resulted in errors ranging from 1% to 20% of the analytical interfacial area estimates, whereas voxel counting and two-point correlation functions overestimated the analytical interfacial area by 20--40%. In addition, the sensitivity of the image analysis algorithms on the resolution of the microtomographic image data was investigated, and the results indicated that there was little or no improvement in the comparison with laboratory estimates for the resolutions and conditions tested.

Porter, Mark L.; Wildenschild, Dorthe; (Oregon State U.)

2010-09-03T23:59:59.000Z

351

Development of Micro/Nano-Scale Sensors for Investigation of Heat Transfer in Multi-Phase Flows  

E-Print Network (OSTI)

The objective of this investigation was to develop micro/nano-scale temperature sensors for measuring surface temperature transients in multi-phase flows and heat transfer. Surface temperature fluctuations were measured on substrates exposed to phase change processes. Prior reports in the literature indicate that these miniature scale surface temperature fluctuations can result in 60-90 percent of the total heat flux during phase change heat transfer. In this study, DTS (Diode Temperature Sensors) were fabricated with a doping depth of ~100 nm on n-type silicon to measure the surface temperature transients on a substrate exposed to droplet impingement cooling. DTS are expected to have better sensor characteristics compared to TFTs (Thin Film Thermocouples), due to their small size and faster response (which comes at the expense of the smaller operating temperature range). Additional advantages of DTS include the availability of robust commercial micro fabrication processes (with diode and transistor node sizes currently in the size range of ~ 30 nm), and that only 2N wire leads can be used to interrogate a set of N x N array of sensors (in contrast thermocouples require 2 N x N wire leads for N x N sensor array). The DTS array was fabricated using conventional semi-conductor processes. The temperature response of the TFT and DTS was also calibrated using NIST standards. Transient temperature response of the DTS was recorded using droplet impingement cooling experiments. The droplet impingement cooling experiments were performed for two different test fluids (acetone and ethanol). An infrared camera was used to verify the surface temperature of the substrate and compare these measurements with the temperature values recorded by individual DTS. PVD (Physical Vapor Deposition) was used for obtaining the catalyst coatings for subsequent CNT synthesis using CVD (Chemical Vapor Deposition) as well as for fabricating the thin film thermocouple (TFT) arrays using the "lift-off" process. Flow boiling experiments were conducted for three different substrates. Flow boiling experiments on bare silicon wafer surface were treated as the control experiment, and the results were compared with that of CNT (Carbon Nano-Tube) coated silicon wafer surfaces. Similar experiments were also performed on a pure copper surface. In addition, experiments were performed using compact condensers. Micro-scale patterns fabricated on the refrigerant side of the compact heat exchanger were observed to cause significant enhancement of the condensation heat transfer coefficient.

Jeon, Sae Il

2011-08-01T23:59:59.000Z

352

DEVELOPMENT OF A COMPUTATIONAL MULTIPHASE FLOW MODEL FOR FISCHER TROPSCH SYNTHESIS IN A SLURRY BUBBLE COLUMN REACTOR  

DOE Green Energy (OSTI)

The Hybrid Energy Systems Testing (HYTEST) Laboratory is being established at the Idaho National Laboratory to develop and test hybrid energy systems with the principal objective to safeguard U.S. Energy Security by reducing dependence on foreign petroleum. A central component of the HYTEST is the slurry bubble column reactor (SBCR) in which the gas-to-liquid reactions will be performed to synthesize transportation fuels using the Fischer Tropsch (FT) process. SBCRs are cylindrical vessels in which gaseous reactants (for example, synthesis gas or syngas) is sparged into a slurry of liquid reaction products and finely dispersed catalyst particles. The catalyst particles are suspended in the slurry by the rising gas bubbles and serve to promote the chemical reaction that converts syngas to a spectrum of longer chain hydrocarbon products, which can be upgraded to gasoline, diesel or jet fuel. These SBCRs operate in the churn-turbulent flow regime which is characterized by complex hydrodynamics, coupled with reacting flow chemistry and heat transfer, that effect reactor performance. The purpose of this work is to develop a computational multiphase fluid dynamic (CMFD) model to aid in understanding the physico-chemical processes occurring in the SBCR. Our team is developing a robust methodology to couple reaction kinetics and mass transfer into a four-field model (consisting of the bulk liquid, small bubbles, large bubbles and solid catalyst particles) that includes twelve species: (1) CO reactant, (2) H2 reactant, (3) hydrocarbon product, and (4) H2O product in small bubbles, large bubbles, and the bulk fluid. Properties of the hydrocarbon product were specified by vapor liquid equilibrium calculations. The absorption and kinetic models, specifically changes in species concentrations, have been incorporated into the mass continuity equation. The reaction rate is determined based on the macrokinetic model for a cobalt catalyst developed by Yates and Satterfield [1]. The model includes heat generation due to the exothermic chemical reaction, as well as heat removal from a constant temperature heat exchanger. Results of the CMFD simulations (similar to those shown in Figure 1) will be presented.

Donna Post Guillen; Tami Grimmett; Anastasia M. Gribik; Steven P. Antal

2010-09-01T23:59:59.000Z

353

Nuclear reactivity control using laser induced polarization  

DOE Patents (OSTI)

A control element for reactivity control of a fission source provides an atomic density of .sup.3 He in a control volume which is effective to control criticality as the .sup.3 He is spin-polarized. Spin-polarization of the .sup.3 He affects the cross section of the control volume for fission neutrons and hence, the reactivity. An irradiation source is directed within the .sup.3 He for spin-polarizing the .sup.3 He. An alkali-metal vapor may be included with the .sup.3 He where a laser spin-polarizes the alkali-metal atoms which in turn, spin-couple with .sup.3 He to spin-polarize the .sup.3 He atoms.

Bowman, Charles D. (Los Alamos, NM)

1991-01-01T23:59:59.000Z

354

Nuclear reactivity control using laser induced polarization  

DOE Patents (OSTI)

A control element for reactivity control of a fission source provides an atomic density of .sup.3 He in a control volume which is effective to control criticality as the .sup.3 He is spin-polarized. Spin-polarization of the .sup.3 He affects the cross section of the control volume for fission neturons and hence, the reactivity. An irradiation source is directed within the .sup.3 He for spin-polarizing the .sup.3 He. An alkali-metal vapor may be included with the .sup.3 He where a laser spin-polarizes the alkali-metal atoms which in turn, spin-couple with .sup.3 He to spin-polarize the .sup.3 He atoms.

Bowman, Charles D. (Los Alamos, NM)

1990-01-01T23:59:59.000Z

355

Reactivity control assembly for nuclear reactor. [LMFBR  

DOE Patents (OSTI)

This invention, which resulted from a contact with the United States Department of Energy, relates to a control mechanism for a nuclear reactor and, more particularly, to an assembly for selectively shifting different numbers of reactivity modifying rods into and out of the core of a nuclear reactor. It has been proposed heretofore to control the reactivity of a breeder reactor by varying the depth of insertion of control rods (e.g., rods containing a fertile material such as ThO/sub 2/) in the core of the reactor, thereby varying the amount of neutron-thermalizing coolant and the amount of neutron-capturing material in the core. This invention relates to a mechanism which can advantageously be used in this type of reactor control system.

Bollinger, L.R.

1982-03-17T23:59:59.000Z

356

Treatment of Radioactive Reactive Mixed Waste  

Science Conference Proceedings (OSTI)

PacificEcoSolutions, Inc. (PEcoS) has installed a plasma gasification system that was recently modified and used to destroy a trimethyl-aluminum mixed waste stream from Los Alamos National Laboratory (LANL.) The unique challenge in handling reactive wastes like trimethyl-aluminum is their propensity to flame instantly on contact with air and to react violently with water. To safely address this issue, PacificEcoSolutions has developed a new feed system to ensure the safe containment of these radioactive reactive wastes during transfer to the gasification unit. The plasma gasification system safely processed the radioactively contaminated trimethyl-metal compounds into metal oxides. The waste stream came from LANL research operations, and had been in storage for seven years, pending treatment options. (authors)

Colby, S.; Turner, Z.; Utley, D. [Pacific EcoSolutions, Inc., 2025 Battelle Boulevard, Richland, Washington 99354 (United States); Duy, C. [Los Alamos National Laboratory - LA-UR-05-8410, Post Office Box 1663 MS J595, Los Alamos, New Mexico 97545 (United States)

2006-07-01T23:59:59.000Z

357

Nuclear reactivity control using laser induced polarization  

DOE Patents (OSTI)

A control element for reactivity control of a fission source provides an atomic density of {sup 3}He in a control volume which is effective to control criticality as the {sup 3}He is spin-polarized. Spin-polarization of the {sup 3}He affects the cross section of the control volume for fission neutrons and hence, the reactivity. An irradiation source is directed within the {sup 3}He for spin-polarizing the {sup 3}He. An alkali-metal vapor may be included with the {sup 3}He where a laser spin-polarizes the alkali-metal atoms which in turn, spin-couple with {sup 3}He to spin-polarize the {sup 3}He atoms. 5 figs.

Bowman, C.D.

1989-05-26T23:59:59.000Z

358

Real time reactive programming in lucid enriched with contexts  

Science Conference Proceedings (OSTI)

We present a synchronous approach to real-time reactive programming in Lucid enriched with contexts as first class objects. The declarative intensional approach allows real-time reactive programs to manipulate both events and state-based representations ... Keywords: contexts, formal verification, intensional programming, real-time reactive programming

Kaiyu Wan; Vasu Alagar; Joey Paquet

2004-09-01T23:59:59.000Z

359

From model conception to verification and validation, a global approach to multiphase Navier-Stoke models with an emphasis on volcanic explosive phenomenology  

Science Conference Proceedings (OSTI)

Large-scale volcanic eruptions are hazardous events that cannot be described by detailed and accurate in situ measurement: hence, little to no real-time data exists to rigorously validate current computer models of these events. In addition, such phenomenology involves highly complex, nonlinear, and unsteady physical behaviors upon many spatial and time scales. As a result, volcanic explosive phenomenology is poorly understood in terms of its physics, and inadequately constrained in terms of initial, boundary, and inflow conditions. Nevertheless, code verification and validation become even more critical because more and more volcanologists use numerical data for assessment and mitigation of volcanic hazards. In this report, we evaluate the process of model and code development in the context of geophysical multiphase flows. We describe: (1) the conception of a theoretical, multiphase, Navier-Stokes model, (2) its implementation into a numerical code, (3) the verification of the code, and (4) the validation of such a model within the context of turbulent and underexpanded jet physics. Within the validation framework, we suggest focusing on the key physics that control the volcanic clouds—namely, momentum-driven supersonic jet and buoyancy-driven turbulent plume. For instance, we propose to compare numerical results against a set of simple and well-constrained analog experiments, which uniquely and unambiguously represent each of the key-phenomenology. Key

Dartevelle, Sebastian

2007-10-01T23:59:59.000Z

360

Groundwater modeling: Application of a multiphase fluid flow model as a decision-making tool for assessing and remediating installation restoration program sites. Master's thesis  

Science Conference Proceedings (OSTI)

This research examined a two-dimensional numerical model, VALOR, which can simulate multiphase fluid flow in soils and groundwater, and evaluated the applicability of the model as a decision-making tool for assessing and remediating IRP sites. Model sensitivity analyses were conducted to study the influence of grid sizes, soil types, and organic release rates on the simulated migration of both light and dense non-aqueous phase liquids (NAPLs). The VALOR model was applied to a case study of a JP-4 release at Wright-Patterson AFB, Ohio. The finer grid sizes provide the most accurate definition of NAPL distribution. The soil type and release rate sensitivity analyses demonstrate that NAPL migrates quicker through coarse sands than fine sand and clay. The light NAPL ponds at the water table and spreads laterally. The dense NAPL migrates through the subsurface and ponds at the aquifer bottom. The fast organic release simulations predict wider vertical pathways of migration. The slow organic release simulations predict higher light NAPL saturation at the water table. The case study indicates that within limits, VALOR may be useful for assessing NAPL distribution, estimating contaminated soil volumes, and evaluating remediation alternatives.... Groundwater modeling, Non-aqueous Phase Liquids: NAPL, Multiphase fluid flow model, Installation Restoration Program, IRP.

Scott, D.J.

1993-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "multiphase reactive geochemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Geochemical data package for the Hanford immobilized low-activity tank waste performance assessment (ILAW PA)  

Science Conference Proceedings (OSTI)

Lockheed Martin Hanford Company (LMHC) is designing and assessing the performance of disposal facilities to receive radioactive wastes that are stored in single- and double-shell tanks at the Hanford Site. The preferred method of disposing of the portion that is classified as low-activity waste is to vitrify the liquid/slurry and place the solid product in near-surface, shallow-land burial facilities. The LMHC project to assess the performance of these disposal facilities is the Hanford Immobilized Low-Activity Tank Waste (ILAW) Performance Assessment (PA) activity. The goal of this project is to provide a reasonable expectation that the disposal of the waste is protective of the general public, groundwater resources, air resources, surface-water resources, and inadvertent intruders. Achieving this goal will require prediction of contaminant migration from the facilities. This migration is expected to occur primarily via the movement of water through the facilities, and the consequent transport of dissolved contaminants in the porewater of the vadose zone. Pacific Northwest National Laboratory assists LMHC in their performance assessment activities. One of the PNNL tasks is to provide estimates of the geochemical properties of the materials comprising the disposal facility, the disturbed region around the facility, and the physically undisturbed sediments below the facility (including the vadose zone sediments and the aquifer sediments in the upper unconfined aquifer). The geochemical properties are expressed as parameters that quantify the adsorption of contaminants and the solubility constraints that might apply for those contaminants that may exceed solubility constraints. The common parameters used to quantify adsorption and solubility are the distribution coefficient (K{sub d}) and the thermodynamic solubility product (K{sub sp}), respectively. In this data package, the authors approximate the solubility of contaminants using a more simplified construct, called the solution concentration limit, a constant value. In future geochemical data packages, they will determine whether a more rigorous measure of solubility is necessary or warranted based on the dose predictions emanating from the ILAW 2001 PA and reviewers' comments. The K{sub d}s and solution concentration limits for each contaminant are direct inputs to subsurface flow and transport codes used to predict the performance of the ILAW system. In addition to the best-estimate K{sub d}s, a reasonable conservative value and a range are provided. They assume that K{sub d} values are log normally distributed over the cited ranges. Currently, they do not give estimates for the range in solubility limits or their uncertainty. However, they supply different values for both the K{sub d}s and solution concentration limits for different spatial zones in the ILAW system and supply time-varying K{sub d}s for the concrete zone, should the final repository design include concrete vaults or cement amendments to buffer the system pH.

DI Kaplan; RJ Serne

2000-02-24T23:59:59.000Z

362

Multiphase and Multicomponent Materials  

Science Conference Proceedings (OSTI)

The microstructure of the adhered material consisted of oxide ligaments ( nanowires, NWs) that served to attach the debris to tool steel surface as revealed by ...

363

Mulitcomponent Multiphase Diffusion  

Science Conference Proceedings (OSTI)

... 54 (2006) p 2431-2439. pdf file; "Hillert, Höglund, and Ĺgren, "Diffusion in interstitial compounds with thermal and stoichiometric defects," J. Appl. ...

2008-07-22T23:59:59.000Z

364

Core-based integrated sedimentologic, stratigraphic, and geochemical analysis of the oil shale bearing Green River Formation, Uinta Basin, Utah  

NLE Websites -- All DOE Office Websites (Extended Search)

DOE Award No.: DE-FE0001243 DOE Award No.: DE-FE0001243 Topical Report CORE-BASED INTEGRATED SEDIMENTOLOGIC, STRATIGRAPHIC, AND GEOCHEMICAL ANALYSIS OF THE OIL SHALE BEARING GREEN RIVER FORMATION, UINTA BASIN, UTAH Submitted by: University of Utah Institute for Clean and Secure Energy 155 South 1452 East, Room 380 Salt Lake City, UT 84112 Prepared for: United States Department of Energy National Energy Technology Laboratory April 2011 Oil & Natural Gas Technology Office of Fossil Energy Core-based integrated sedimentologic, stratigraphic, and geochemical analysis of the oil shale bearing Green River Formation, Uinta Basin, Utah Topical Report Reporting Period: October 31, 2009 through March 31, 2011 Authors: Lauren P. Birgenheier, Energy and Geoscience Insitute, University of Utah

365

Geologic, geophysical, and geochemical aspects of site-specific studies of the geopressured-geothermal energy resource of southern Louisiana. Final report  

DOE Green Energy (OSTI)

The report consists of four sections dealing with progress in evaluating geologic, geochemical, and geophysical aspects of geopressured-geothermal energy resources in Louisiana. Separate abstracts have been prepared for the individual sections. (ACR)

Pilger, R.H. Jr. (ed.)

1985-01-01T23:59:59.000Z

366

Preparation of reactive beta-dicalcium silicate  

DOE Patents (OSTI)

This invention relates to the preparation of fine particles of reactive beta-dicalcium silicate by means of a solid state process which comprises firing a mixture of calcium sulfate, silica and a reducing additive selected from the group consisting of calcium sulfide, carbon, carbon monoxide, methane and hydrogen, at a temperature of about 850.degree.-1000.degree. C. A carrier gas such as nitrogen or carbon dioxide may also be added, if desired. A high concentration of sulfur dioxide is a by-product of this process.

Shen, Ming-Shing (Laramie, WY, NJ); Chen, James M. (Rahway, NJ); Yang, Ralph T. (Amherst, NY)

1982-01-01T23:59:59.000Z

367

Preparation of reactive beta-dicalcium silicate  

DOE Patents (OSTI)

This invention relates to the preparation of fine particles of reactive beta-dicalcium silicate by means of a solid state process which comprises firing a mixture of calcium sulfate, silica, and a reducing additive selected from the group consisting of calcium sulfide, carbon, carbon monoxide, methane, and hydrogen, at a temperature of about 850 to 1000/sup 0/C. A carrier gas such as nitrogen or carbon dioxide may also be added, if desired. A high concentration of sulfur dioxide is a by-product of this process.

Shen, M.S.; Chen, J.M.; Yang, R.T.

1980-02-28T23:59:59.000Z

368

Reactive sticking coefficients of silane on silicon  

SciTech Connect

Reactive sticking coefficients (RSCs) were measured for silane and disilane on polycrystalline silicon for a wide range of temperature and flux (pressure) conditions. The data were obtained from deposition rate measurements using molecular beam scattering and a very low pressure cold wall reactor. The RSCs have non-Arrhenius temperature dependences and decreases with increasing flux at low (710/sup 0/) temperatures. A simple model involving dissociative adsorption of silane is consistent with these results. The results are compared with previous studies of the SiH/sub 4//Si(s) reaction.

Buss, R.J.; Ho, P.; Breiland, W.G.; Coltrin, M.E.

1988-09-15T23:59:59.000Z

369

Injection and Reservoir Hazard Management: Mechanical Deformation and Geochemical Alteration at the InSalah CO2 Storage Project  

NLE Websites -- All DOE Office Websites (Extended Search)

Injection and Reservoir Hazard Injection and Reservoir Hazard Management: Mechanical Deformation and Geochemical Alteration at the In Salah CO 2 Storage Project Background Safe and permanent storage of carbon dioxide (CO 2 ) in geologic reservoirs is critical to geologic sequestration. The In Salah Project (joint venture of British Petroleum (BP), Sonatrach, and StatoilHydro) has two fundamental goals: (1) 25-30 years of 9 billion cubic feet per year (bcfy) natural gas production from 8 fields in the Algerian

370

The application of PHREEQCi, a geochemical computer program, to aid in the management of a wastewater treatment wetland  

E-Print Network (OSTI)

In the past decade, constructed wetlands have become popular for treating coal-generated acid mine drainage and leachate from coal-ash disposal areas. The goal of the wetland manager is to design a system in which the pH is neutralized, toxic metals are removed, and wetland discharge meets or exceeds discharge standards for water quality. This is typically accomplished by using a combination of wetlands, ponds, and limestone drains. The treatment capability of a constructed wetland is based on relationships among dissolved oxygen (DO), pH, and metal speciation. The aim of this research was to determine if PHREEQCi, a geochemical computer program, could be used in wetland management and design. The wetland site chosen for this study was at a Texas Municipal Power Agency (TMPA) plant located in Grimes County, Texas and was created to treat leachate from a solid waste disposal area where coal ash and SO? scrubber sludge was deposited. The leachate contains significant concentrations of sulfate, chloride, total dissolved solids (TDS), arsenic, and selenium. Using PHREEQCi, geochemical speciation models were created to study the interrelationships between critical chemical components at the TMPA site in order to establish an optimum set of conditions to improve treatment capability and to avoid wetland failure. The results of the geochemical speciation modeling indicated a challenging situation for a wetland manager because different species precipitate under contrasting environments. In order to apply the geochemical speciation results to the design of the TMPA site, two conditions must be recognized. First, metal removal is best accomplished by generating alkaline and oxidative conditions to promote metal-oxide precipitation. Second, sulfate can be controlled under reducing environments where it is converted to sulfide and metal sulfides precipitate. Chlorides are very soluble and no viable conclusions as to the most appropriate removal method could be postulated. TDS has an ambiguous composition and could not be modeled using PHREEQCi.

Mitzman, Stephanie

1999-01-01T23:59:59.000Z

371

Geochemical and physical properties of soils and shallow sediments at the Savannah River Site  

Science Conference Proceedings (OSTI)

A program to characterize the geochemical and physical properties of the unimpacted soils and shallow sediments at the Savannah River Site (SRS) has been completed. The maximum, minimum, median, standard deviation, and mean values for metals, radionuclides, inorganic anions, organic compounds, and agricultural indicator parameters are summarized for six soil series that were identified as representative of the 29 soil series at SRS. The soils from unimpacted areas of SRS are typical of soils found in moderately aggressive weathering environments, including the southeastern United States. Appendix 8 organic compounds were detected in all samples. Since these constituents are not generally present in soil, this portion of the investigation was intended to assess possible laboratory artifacts. An additional objective of the SRS Soil Study was to determine if the composition of the split spoon sampler biased chemical analysis of the soils. Twenty-five duplicate samples were analyzed for a number of metals, radiological and agricultural parameters, and organics by two laboratories currently contracted with to analyze samples during waste site characterization. In all cases, the absolute values of the average differences are relatively small compared to the overall variability in the population. 31 refs., 14 figs., 48 tabs.

Looney, B.B.; Eddy, C.A.; Ramdeen, M.; Pickett, J. (Savannah River Lab., Aiken, SC (USA)); Rogers, V. (Soil Conservation Service, Aiken, SC (USA). Savannah River Site Savannah River Lab., Aiken, SC (USA)); Scott, M.T.; Shirley, P.A. (Sirrine Environmental Consultants, Greenville, SC (USA))

1990-08-31T23:59:59.000Z

372

Geochemical Fingerprinting of Coltan Ores by Machine Learning on Uneven Datasets  

Science Conference Proceedings (OSTI)

Two modern machine learning techniques, Linear Programming Boosting (LPBoost) and Support Vector Machines (SVMs), are introduced and applied to a geochemical dataset of niobium-tantalum ('coltan') ores from Central Africa to demonstrate how such information may be used to distinguish ore provenance, i.e., place of origin. The compositional data used include uni- and multivariate outliers and elemental distributions are not described by parametric frequency distribution functions. The 'soft margin' techniques of LPBoost and SVMs can be applied to such data. Optimization of their learning parameters results in an average accuracy of up to c. 92%, if spot measurements are assessed to estimate the provenance of ore samples originating from two geographically defined source areas. A parameterized performance measure, together with common methods for its optimization, was evaluated to account for the presence of uneven datasets. Optimization of the classification function threshold improves the performance, as class importance is shifted towards one of those classes. For this dataset, the average performance of the SVMs is significantly better compared to that of LPBoost.

Savu-Krohn, Christian, E-mail: christian.savu-krohn@unileoben.ac.at; Rantitsch, Gerd, E-mail: gerd.rantitsch@unileoben.ac.at [Montanuniversitaet Leoben, Department of Applied Geosciences and Geophysics (Austria); Auer, Peter, E-mail: auer@unileoben.ac.at [Chair for Information Technology, Montanuniversitaet Leoben (Austria); Melcher, Frank, E-mail: frank.melcher@bgr.de; Graupner, Torsten, E-mail: torsten.graupner@bgr.de [Federal Institute for Geosciences and Natural Resources (Germany)

2011-09-15T23:59:59.000Z

373

Changes in Bacterial And Archaeal Community Structure And Functional Diversity Along a Geochemically Variable Soil Profile  

SciTech Connect

Spatial heterogeneity in physical, chemical, and biological properties of soils allows for the proliferation of diverse microbial communities. Factors influencing the structuring of microbial communities, including availability of nutrients and water, pH, and soil texture, can vary considerably with soil depth and within soil aggregates. Here we investigated changes in the microbial and functional communities within soil aggregates obtained along a soil profile spanning the surface, vadose zone, and saturated soil environments. The composition and diversity of microbial communities and specific functional groups involved in key pathways in the geochemical cycling of nitrogen, Fe, and sulfur were characterized using a coupled approach involving cultivation-independent analysis of both 16S rRNA (bacterial and archaeal) and functional genes (amoA and dsrAB) as well as cultivation-based analysis of Fe(III)-reducing organisms. Here we found that the microbial communities and putative ammonia-oxidizing and Fe(III)-reducing communities varied greatly along the soil profile, likely reflecting differences in carbon availability, water content, and pH. In particular, the Crenarchaeota 16S rRNA sequences are largely unique to each horizon, sharing a distribution and diversity similar to those of the putative (amoA-based) ammonia-oxidizing archaeal community. Anaerobic microenvironments within soil aggregates also appear to allow for both anaerobic- and aerobic-based metabolisms, further highlighting the complexity and spatial heterogeneity impacting microbial community structure and metabolic potential within soils.

Hansel, C.M.; Fendorf, S.; Jardine, P.M.; Francis, C.A.

2009-05-18T23:59:59.000Z

374

Mechanistic Reactive Burn Modeling of Solid Explosives  

SciTech Connect

This report describes a computational framework for reactive burn modeling of solid explosives and the development of a test case where physical mechanisms represent RDX or RDX-based materials. The report is a sequel to LA-13794-MS, ''A Unifying Framework for Hot Spots and the Ignition of Energetic Materials,'' where we proposed a new approach to the building of a general purpose model that captures the essential features of the three primary origins of hot-spot formation: void collapse, shear banding, friction. The purpose of the present report is to describe the continuing task of coupling the unifying hot-spot model to hydrodynamic calculations to develop a mechanistic reactive burn model. The key components of the coupling include energy localization, the growth of hot spots, overall hot-spot behavior, and a phase-averaged mixture equation of state (EOS) in a Mie-Grueneisen form. The nucleation and growth of locally heated regions is modeled by a phenomenological treatment as well as a statistical model based on an exponential size distribution. The Mie-Grueneisen form of the EOS is one of many possible choices and is not a critical selection for implementing the model. In this report, model calculations are limited to proof-of-concept illustrations for shock loading. Results include (1) shock ignition and growth-to-detonation, (2) double shock ignition, and (3) quenching and reignition. A comparative study of Pop-plots is discussed based on the statistical model.

Y.Horie; Y.Hamate; D.Greening

2003-04-01T23:59:59.000Z

375

Reactive thermal waves in energetic materials  

SciTech Connect

Reactive thermal waves (RTWs) arise in several energetic material applications, including self-propagating high-temperature synthesis (SHS), high explosive cookoff, and the detonation of heterogeneous explosives. In this paper I exmaine ideal RTWs, by which I mean that (1) material motion is neglected, (2) the state dependence of reaction is Arrhenius in the temperature, and (3) the reaction rate is modulated by an arbitrary mass-fraction-based reaction progress function. Numerical simulations demonstrate that one's natural intuition, which is based mainly upon experience with inert materials and which leads one to expect diffusion processes to become relatively slow after a short time period, is invalid for high energy, state-sensitive reactive systems. Instead, theory predicts that RTWs can propagate at very high speeds. This result agrees with estimates for detonating heterogeneous explosives, which indicate that RTWs must spread from hot-spot nucleation sites at rates comparable to the detonation speed in order to produce experimentally-observed reaction zone thicknesses. Using dimensionless scaling and further invoking the high activation energy approximation, I obtain an analytic formula for the steady plane RTW speed from numerical calculations. I then compute the RTW speed for real explosives, and discuss aspects of their behavior.

Hill, Larry G [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

376

Mild coal pretreatment to improve liquefaction reactivity  

SciTech Connect

This report describes work completed during the fifth quarter of a three year project to study the effects of mild chemical pretreatment on coal dissolution reactivity during low severity liquefaction or coal/oil coprocessing. The overall objective of this research is to elucidate changes in the chemical and physical structure of coal by pretreating with methanol or other simple organic solvent and a trace amount of hydrochloric acid and measure the influence of these changes on coal dissolution reactivity. Work this quarter focused on analytical characterization of untreated and treated Wyodak subbituminous coal and Illinois {number sign}6 bituminous coal. Mossbauer spectroscopy and x-ray diffraction techniques were used to study the effect of methanol/HCl pretreatment on the composition of each coal's inorganic phase. Results from these studies indicated that calcite is largely removed during pretreatment, but that other mineral species such as pyrite are unaffected. This finding is significant, since calcite removal appears to directly correlate with low severity liquefaction enhancement. Further work will be performed to study this phenomenon in more detail.

Miller, R.L.

1991-01-01T23:59:59.000Z

377

Actinide and xenon reactivity effects in ATW high flux systems  

SciTech Connect

In this paper, initial system reactivity response to flux changes caused by the actinides and xenon are investigated separately for a high flux ATW system. The maximum change in reactivity after a flux change due to the effect of the changing quantities of actinides is generally at least two orders of magnitude smaller than either the positive or negative reactivity effect associated with xenon after a shutdown or start-up. In any transient flux event, the reactivity response of the system to xenon will generally occlude the response due to the actinides.

Woosley, M.; Olson, K.; Henderson, D. L.; Sailor, W. C. [Department of Mechanical, Aerospace, and Nuclear Engineering University of Virginia, Charlottesville, Virginia 22903 (United States); Department of Nuclear Engineering and Engineering Physics University of Wisconsin, Madison, Wisconsin 53706-1687 (United States); Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

1995-09-15T23:59:59.000Z

378

Knudsen Layer Reduction of Fusion Reactivity Kim Molvig and Nelson...  

NLE Websites -- All DOE Office Websites (Extended Search)

fusion cross section determine Gamow peak in the fusion reactivity. 2 Inertially confined fusion systems typically have plasma fuel enveloped by a cold non-reacting region or...

379

SP-19: Electrochemistry of Enargite: Reactivity in Alkaline Solutions  

Science Conference Proceedings (OSTI)

The reactivity of enargite samples from Montana, US and Quiruvilca, Peru were studied under alkaline conditions, pH range of 8-13, using a cyclic voltammetry ...

380

Advancing Reactive Tracer Methods for Measuring Thermal Evolution...  

Open Energy Info (EERE)

History Facebook icon Twitter icon Advancing Reactive Tracer Methods for Measuring Thermal Evolution in CO2- and Water-Based Geothermal Reservoirs Geothermal Lab Call Project...

Note: This page contains sample records for the topic "multiphase reactive geochemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Chombo-Crunch: Advanced Simulation of Subsurface Flow and Reactive...  

NLE Websites -- All DOE Office Websites (Extended Search)

Chombo-Crunch: Advanced Simulation of Subsurface Flow and Reactive Transport Processes Associated with Carbon Sequestration PI Name: David Trebotich Institution: Lawrence Berkeley...

382

Geochemical Data Package for the 2005 Hanford Integrated Disposal Facility Performance Assessment  

Science Conference Proceedings (OSTI)

CH2M HILL Hanford Group, Inc. (CH2M HILL) is designing and assessing the performance of an integrated disposal facility (IDF) to receive low-level waste (LLW), mixed low-level waste (MLLW), immobilized low-activity waste (ILAW), and failed or decommissioned melters. The CH2M HILL project to assess the performance of this disposal facility is the Hanford IDF Performance Assessment (PA) activity. The goal of the Hanford IDF PA activity is to provide a reasonable expectation that the disposal of the waste is protective of the general public, groundwater resources, air resources, surface-water resources, and inadvertent intruders. Achieving this goal will require prediction of contaminant migration from the facilities. This migration is expected to occur primarily via the movement of water through the facilities, and the consequent transport of dissolved contaminants in the vadose zone to groundwater where contaminants may be re-introduced to receptors via drinking water wells or mixing in the Columbia River. Pacific Northwest National Laboratory (PNNL) assists CH2M HILL in their performance assessment activities. One of the PNNL tasks is to provide estimates of the geochemical properties of the materials comprising the IDF, the disturbed region around the facility, and the physically undisturbed sediments below the facility (including the vadose zone sediments and the aquifer sediments in the upper unconfined aquifer). The geochemical properties are expressed as parameters that quantify the adsorption of contaminants and the solubility constraints that might apply for those contaminants that may exceed solubility constraints. The common parameters used to quantify adsorption and solubility are the distribution coefficient (Kd) and the thermodynamic solubility product (Ksp), respectively. In this data package, we approximate the solubility of contaminants using a more simplified construct, called the solution concentration limit, a constant value. The Kd values and solution concentration limits for each contaminant are direct inputs to subsurface flow and transport codes used to predict the performance of the IDF system. In addition to the best-estimate Kd values, a reasonable conservative value and a range are provided. The data package does not list estimates for the range in solubility limits or their uncertainty. However, the data package does provide different values for both the Kd values and solution concentration limits for different spatial zones in the IDF system and does supply time-varying Kd values for the cement solidified waste. The Kd values and solution concentration limits presented for each contaminant were previously presented in a report prepared by Kaplan and Serne (2000) for the 2001 ILAW PA, and have been updated to include applicable data from investigations completed since the issuance of that report and improvements in our understanding of the geochemistry specific to Hanford. A discussion is also included of the evolution of the Kd values recommended from the original 1999 ILAW PA through the 2001 ILAW and 2003 Supplement PAs to the current values to be used for the 2005 IDF PA for the key contaminants of concern: Cr(VI), nitrate, 129I, 79Se, 99Tc, and U(VI). This discussion provides the rationale for why certain Kd have changed with time.

Krupka, Kenneth M.; Serne, R JEFFREY.; Kaplan, D I.

2004-09-30T23:59:59.000Z

383

Instrumentation @ Catalysis: Reactivity and Structure Group | Chemistry  

NLE Websites -- All DOE Office Websites (Extended Search)

Instrumentation Instrumentation The Catalysis Group at BNL is leading research initiatives into the development of new tools and techniques that focus on the characterization of heterogeneous catalytic reactions and catalysts using imaging, spectroscopy and scattering techniques and integrated combinations of them under reaction conditions to unravel the morphology, chemical and structural properties, of catalysts, respectively. These efforts revolve around the use of synchrotron radiation (NSLS), electrons (CFN) and quantum tunneling tools with particular thrusts into imaging, spectroscopy and scattering. Groups Instrumentation(BNL) Three UHV chambers with diverse instrumentation for surface characterization: LEED, UPS, XPS, AES, TPD, ISS, PM-AP-IRRAS, Reactivity Cell. All the systems include ancillary instrumentation such as sputtering guns and metal evaporators. The IRRAS system was retrofitted with an ambient pressure (AP) cell on top of the UHV system. The sample can be prepared and characterized in UHV and then transfer in vacuum to the AP cell.

384

Using laboratory flow experiments and reactive chemical transport modeling for designing waterflooding of the Agua Fria Reservoir, Poza Rica-Altamira Field, Mexico  

SciTech Connect

Waterflooding for enhanced oil recovery requires that injected waters must be chemically compatible with connate reservoir waters, in order to avoid mineral dissolution-and-precipitation cycles that could seriously degrade formation permeability and injectivity. Formation plugging is a concern especially in reservoirs with a large content of carbonates, such as calcite and dolomite, as such minerals typically react rapidly with an aqueous phase, and have strongly temperature-dependent solubility. Clay swelling can also pose problems. During a preliminary waterflooding pilot project, the Poza Rica-Altamira oil field, bordering the Gulf coast in the eastern part of Mexico, experienced injectivity loss after five months of reinjection of formation waters into well AF-847 in 1999. Acidizing with HCl restored injectivity. We report on laboratory experiments and reactive chemistry modeling studies that were undertaken in preparation for long-term waterflooding at Agua Frma. Using analogous core plugs obtained from the same reservoir interval, laboratory coreflood experiments were conducted to examine sensitivity of mineral dissolution and precipitation effects to water composition. Native reservoir water, chemically altered waters, and distilled water were used, and temporal changes in core permeability, mineral abundances and aqueous concentrations of solutes were monitored. The experiments were simulated with the multi-phase, nonisothermal reactive transport code TOUGHREACT, and reasonable to good agreement was obtained for changes in solute concentrations. Clay swelling caused an additional impact on permeability behavior during coreflood experiments, whereas the modeled permeability depends exclusively on chemical processes. TOUGHREACT was then used for reservoir-scale simulation of injecting ambient-temperature water (30 C, 86 F) into a reservoir with initial temperature of 80 C (176 F). Untreated native reservoir water was found to cause serious porosity and permeability reduction due to calcite precipitation, which is promoted by the retrograde solubility of this mineral. Using treated water that performed well in the laboratory flow experiments was found to avoid excessive precipitation, and allowed injection to proceed.

Birkle, P.; Pruess, K.; Xu, T.; Figueroa, R.A. Hernandez; Lopez, M. Diaz; Lopez, E. Contreras

2008-10-01T23:59:59.000Z

385

CO2–brine–caprock interaction: Reactivity experiments on Eau Claire shale and a review of relevant literature  

SciTech Connect

Long term containment of stored CO2 in deep geological reservoirs will depend on the performance of the caprock to prevent the buoyant CO2 from escaping to shallow drinking water aquifers or the ground surface. Here we report new laboratory experiments on CO2-brine-caprock interactions and a review of the relevant literature. The Eau Claire Formation is the caprock overlying the Mount Simon sandstone formation, one of the target geological CO2 storage reservoirs in the Midwest USA region. Batch experiments of Eau Claire shale dissolution in brine were conducted at 200 C and 300 bars to test the extent of fluid-rock reactions. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis indicate minor dissolution of K-feldspar and anhydrite, and precipitation of pore-filling and pore-bridging illite and/or smectite, and siderite in the vicinity of pyrite. We also reviewed relevant reactivity experiments, modeling work, and field observations in the literature in an attempt to help define the framework for future studies on the geochemical systems of the caprock overlain on geological CO2 storage formations. Reactivity of the caprock is generally shown to be low and limited to the vicinity of the CO2-caprock interface, and is related to the original caprock mineralogical and petrophysical properties. Stable isotope studies indicate that CO2 exists in both free phase and dissolved phase within the caprock. Carbonate and feldspar dissolution is reported in most studies, along with clay and secondary carbonate precipitation. Currently, research is mainly focused on the micro-fracture scale geochemistry of the shaly caprock. More attention is required on the potential pore scale reactions that may become significant given the long time scale associated with geological carbon storage

Liua, Faye; Lua, Peng; Griffith, Craig; Hedges, Sheila W.; Soong, Yee; Hellevang, Helge; Zhua,Chen

2012-01-01T23:59:59.000Z

386

Artificial bee colony algorithm solution for optimal reactive power flow  

Science Conference Proceedings (OSTI)

Artificial bee colony (ABC) algorithm is an optimization algorithm based on the intelligent foraging behavior of honeybee swarm. Optimal reactive power flow (ORPF) based on ABC algorithm to minimize active power loss in power systems is studied in this ... Keywords: Artificial bee colony, Optimal reactive power flow, Penalty function, Power system

Kür?at Ayan; Ula? K?l?ç

2012-05-01T23:59:59.000Z

387

A formal approach for the development of reactive systems  

Science Conference Proceedings (OSTI)

Context: This paper deals with the development and verification of liveness properties on reactive systems using the Event-B method. By considering the limitation of the Event-B method to invariance properties, we propose to apply the language TLA^+ ... Keywords: Event-B method, Language TLA+, Liveness properties, Reactive systems, Refinement, Verification

Olfa Mosbahi; Leila Jemni Ben Ayed; Mohamed Khalgui

2011-01-01T23:59:59.000Z

388

MARKETS FOR REACTIVE POWER AND RELIABILITY: A WHITE PAPER  

E-Print Network (OSTI)

1 MARKETS FOR REACTIVE POWER AND RELIABILITY: A WHITE PAPER Engineering and Economics as efficient and optimal production and prices for real and reactive power. The purpose of this paper delivery of electric power. To accomplish this end, the paper opens with specification of an economic

389

Differential evolution approach for optimal reactive power dispatch  

Science Conference Proceedings (OSTI)

Differential evolution based optimal reactive power dispatch for real power loss minimization in power system is presented in this paper. The proposed methodology determines control variable settings such as generator terminal voltages, tap positions ... Keywords: Differential evolution, Loss minimization, Optimal power flow, Penalty function, Reactive power dispatch

M. Varadarajan; K. S. Swarup

2008-09-01T23:59:59.000Z

390

Reactive Power Compensation Technologies, State-of-the-Art Review  

E-Print Network (OSTI)

reactors to provide or absorb the required reactive power have been developed [7], [8], [9]. Also, the use static VAR generators, using power electronic technologies have been proposed and developed [7 compensators (SVC) consist of standard reactive power shunt elements (reactors and capacitors) which

Rudnick, Hugh

391

Modeling brine-rock interactions in an enhanced geothermal system deep fractured reservoir at Soultz-Sous-Forets (France): a joint approach using two geochemical codes: frachem and toughreact  

E-Print Network (OSTI)

150 p. Bächler, D. , Durst, P. , Evans, K. , Hopkirk, R. ,in Mineralogy, 29: 259-308. Durst, P. , (2002). Geochemical1999. Rabemanana, V. , Durst, P. , Bächler, D. , Vuataz,

Andre, Laurent; Spycher, Nicolas; Xu, Tianfu; Vuataz, Francois-D.; Pruess, Karsten.

2006-01-01T23:59:59.000Z

392

Variational reactivity estimates: new analyses and new results  

SciTech Connect

A modified form of the variational estimate of the reactivity worth ofa perturbation was previously developed to extend the range of applicability of variational perturbation theory for perturbations leading to negative reactivity worths. Recent numerical results challenged the assumptions behind the modified form. In this paper, more results are obtained, leading to the conclusion that sometimes the modified form extends the range ofapplicability of variational perturbation theory for positive reactivity worths as well, and sometimes the standard variational form is more accurate for negative-reactivity perturbations. In addition, this paper proves that using the exact generalized adjoint function would lead to an inaccurate variational reactivity estimate when the error in the first-order estimate is large; the standard generalized adjoint function, an approximation to the exact one, leads to Lore accurate results. This conclusion is also demonstrated numerically. Transport calculations use the PARTISN multi group discrete ordinates code

Favorite, Jeffrey A [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

393

Geological, geochemical, and operational summary, aurora well, OCS Y-0943-1, Beaufort Sea, Alaska. Final report  

Science Conference Proceedings (OSTI)

The Aurora well is located just off the coast of the Arctic National Wildlife Refuge (ANWR). The well was spudded November 2, 1987, in 68 ft of water and plugged and abandoned 286 days later on August 30, 1988, after drilling to a total depth (TD) of 18,325 ft below the Kelly Bushing (RKB). The report presents our interpretations of the geologic and geochemical information collected from the Aurora well. Additionally, a significant section of the report is devoted to the operational aspects of drilling the Aurora well.

Paul, L.E.; Choromanski, D.R.; Turner, R.F.; Flett, T.O.; Paul, L.E.

1994-01-01T23:59:59.000Z

394

Geochemical Characterization of Chromate Contamination in the 100 Area Vadose Zone at the Hanford Site  

Science Conference Proceedings (OSTI)

The major objectives of the proposed study were to: 1.) determine the leaching characteristics of hexavalent chromium [Cr(VI)] from contaminated sediments collected from 100 Area spill sites; 2.) elucidate possible Cr(VI) mineral and/or chemical associations that may be responsible for Cr(VI) retention in the Hanford Site 100 Areas through the use of i.) macroscopic leaching studies and ii.) microscale characterization of contaminated sediments; and 3.) provide information to construct a conceptual model of Cr(VI) geochemistry in the Hanford 100 Area vadose zone. In addressing these objectives, additional benefits accrued were: (1) a fuller understanding of Cr(VI) entrained in the vadose zone that will that can be utilized in modeling potential Cr(VI) source terms, and (2) accelerating the Columbia River 100 Area corridor cleanup by providing valuable information to develop remedial action based on a fundamental understanding of Cr(VI) vadose zone geochemistry. A series of macroscopic column experiments were conducted with contaminated and uncontaminated sediments to study Cr(VI) desorption patterns in aged and freshly contaminated sediments, evaluate the transport characteristics of dichromate liquid retrieved from old pipelines of the 100 Area; and estimate the effect of strongly reducing liquid on the reduction and transport of Cr(VI). Column experiments used the with the column studies. Cr(VI) is found as ubiquitous coatings on sediment grain surfaces. Small, higher concentration, chromium sites are associated with secondary clay mineral inclusions, with occasional barium chromate minerals, and reduced to Cr(III) in association with iron oxides that are most likely magnetite primary minerals. Within the restricted access domains of sediment matrix, ferrous iron could also diffuse from in situ, high-surface-area minerals to cause the reductive immobilization of chromate. This process may be favored at microscale geochemical zones where ferrous iron could be supplied. Once nucleated, micrometer-scale precipitates are favored as growing locales for further accumulation, causing the formation of discrete zones of Cr(III).

Dresel, P. Evan; Qafoku, Nikolla; McKinley, James P.; Fruchter, Jonathan S.; Ainsworth, Calvin C.; Liu, Chongxuan; Ilton, Eugene S.; Phillips, J. L.

2008-07-16T23:59:59.000Z

395

Final Report: Molecular Basis for Microbial Adhesion and Geochemical Surface Reactions: A Study Across Scales  

SciTech Connect

Computational chemistry was used to help provide a molecular level description of the interactions of Gram-negative microbial membranes with subsurface materials. The goal is to develop a better understanding of the molecular processes involved in microbial metal binding, microbial attachment to mineral surfaces, and, eventually, oxidation/reduction reactions (electron transfer) that can occur at these surfaces and are mediated by the bacterial exterior surface. The project focused on the interaction of the outer microbial membrane, which is dominated by an exterior lipopolysaccharide (LPS) portion, of Pseudomonas aeruginosa with the mineral goethite and with solvated ions in the environment. This was originally a collaborative project with T.P. Straatsma and B. Lowery of the Pacific Northwest National Laboratory. The University of Alabama effort used electronic structure calculations to predict the molecular behavior of ions in solution and the behavior of the sugars which form a critical part of the LPS. The interactions of the sugars with metal ions are expected to dominate much of the microscopic structure and transport phenomena in the LPS. This work, in combination with the molecular dynamics simulations of Straatsma and the experimental electrochemistry and microscopy measurements of Lowry, both at PNNL, is providing new insights into the detailed molecular behavior of these membranes in geochemical environments. The effort at The University of Alabama has three components: solvation energies and structures of ions in solution, prediction of the acidity of the critical groups in the sugars in the LPS, and binding of metal ions to the sugar anions. An important aspect of the structure of the LPS membrane as well as ion transport in the LPS is the ability of the sugar side groups such as the carboxylic acids and the phosphates to bind positively charged ions. We are studying the acidity of the acidic side groups in order to better understand the ability of these groups to bind metal ions. We need to understand the solvation properties of the metal ions in solution and their ability to bind not only to the sugars but to proteins and to other anions. Our goal is then to be able to predict the ability of the side groups to bind metal ions. One result from the earlier molecular dynamics simulations is the exclusion of water from the inner hydrophobic part of the membrane. We thus need to investigate the binding of the cations in media with different dielectric constants.

Dixon, David Adams [The University of Alabama

2013-06-27T23:59:59.000Z

396

Early maturation processes in coal. Part 2: Reactive dynamics simulations using the ReaxFF reactive force field on Morwell Brown coal structures  

E-Print Network (OSTI)

Early maturation processes in coal. Part 2: Reactive dynamics simulations using the ReaxFF reactive force field on Morwell Brown coal structures Elodie Salmon a , Adri C.T. van Duin b , François Lorant Brown coal using the ReaxFF reactive force field. We find that these reactive MD simulations

Goddard III, William A.

397

Reactive sticking coefficients of silane on silicon  

SciTech Connect

We have investigated the reaction of room-temperature silane and disilane on a hot polycrystalline silicon surface using both a collision-free molecular beam and a very low pressure CVD cell. Reactive sticking coefficients were obtained from deposition rate data over a wide range of temperatures and silane (disilane) fluxes. The RSCs are substantially less than one, ranging from 6 x 10/sup -5/ to 4 x 10/sup -2/. For silane we observed curved Arrhenius plots with slopes decreasing from approx.60 kcal mol/sup -1/ at low temperatures to approx.2 kcal mol/sup -1/ at higher temperatures. The RSCs are independent of flux (pressure) at 1040/sup 0/C, but vary as flux to the approx.-1/2 power at 710/sup 0/C. A model comprised of a dissociative adsorption mechanism with competing associative desorption and reaction was found to give reasonable agreement. For disilane, we observed RSCs that were roughly ten times higher than those for silane. We also observed a curved Arrhenius plot and a flux dependence at 710/sup 0/C for disilane. 22 refs., 5 figs.

Buss, R.J.; Ho, P.; Breiland, W.G.; Coltrin, M.E.

1987-01-01T23:59:59.000Z

398

Reactivity of coals under coprocessing conditions  

DOE Green Energy (OSTI)

In the recent years greater interest has developed for processes involving coal and petroleum fractions to produce distillate fuels. Coprocessing is especially attractive as a direct liquefaction process because it involves the use of heavy petroleum fractions, so both coal and heavy petroleum resids are upgraded simultaneously. The main distinction of coprocessing from other direct liquefaction processes is that coprocessing is more complex from a chemical standpoint than direct liquefaction processes which use traditional solvents, due to the greater variety of hydrocarbons (aromatic from the coal and aliphatics from the petroleum) present in the system. Therefore, need arises for better understanding of the chemical and physical interactions during coprocessing. The aim of the present study is to examine the influence of reaction conditions, coal and petroleum resid properties as well as the compatibility of the coal/petroleum resid pairs in terms of structural components on total coal conversion. Special focus will be given to the reactivity of coals and interaction of the coal and resid which lead to anisotropic coke.

Tomic, J.; Schobert, H.H.

1992-06-01T23:59:59.000Z

399

Reactivity of coals under coprocessing conditions  

DOE Green Energy (OSTI)

In the recent years greater interest has developed for processes involving coal and petroleum fractions to produce distillate fuels. Coprocessing is especially attractive as a direct liquefaction process because it involves the use of heavy petroleum fractions, so both coal and heavy petroleum resids are upgraded simultaneously. The main distinction of coprocessing from other direct liquefaction processes is that coprocessing is more complex from a chemical standpoint than direct liquefaction processes which use traditional solvents, due to the greater variety of hydrocarbons (aromatic from the coal and aliphatics from the petroleum) present in the system. Therefore, need arises for better understanding of the chemical and physical interactions during coprocessing. The aim of the present study is to examine the influence of reaction conditions, coal and petroleum resid properties as well as the compatibility of the coal/petroleum resid pairs in terms of structural components on total coal conversion. Special focus will be given to the reactivity of coals and interaction of the coal and resid which lead to anisotropic coke.

Tomic, J.; Schobert, H.H.

1992-01-01T23:59:59.000Z

400

Advanced Simulation Capability for Environmental Management  

Multi-Process High Performance Computing Simulator Modular simulation capability for barrier and waste form degradation, multiphase flow and reactive ...

Note: This page contains sample records for the topic "multiphase reactive geochemical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Geologic, geochemical, and geographic controls on NORM in produced water from Texas oil, gas, and geothermal reservoirs. Final report  

DOE Green Energy (OSTI)

Water from Texas oil, gas, and geothermal wells contains natural radioactivity that ranges from several hundred to several thousand Picocuries per liter (pCi/L). This natural radioactivity in produced fluids and the scale that forms in producing and processing equipment can lead to increased concerns for worker safety and additional costs for handling and disposing of water and scale. Naturally occurring radioactive materials (NORM) in oil and gas operations are mainly caused by concentrations of radium-226 ({sup 226}Ra) and radium-228 ({sup 228}Ra), daughter products of uranium-238 ({sup 238}U) and thorium-232 ({sup 232}Th), respectively, in barite scale. We examined (1) the geographic distribution of high NORM levels in oil-producing and gas-processing equipment, (2) geologic controls on uranium (U), thorium (Th), and radium (Ra) in sedimentary basins and reservoirs, (3) mineralogy of NORM scale, (4) chemical variability and potential to form barite scale in Texas formation waters, (5) Ra activity in Texas formation waters, and (6) geochemical controls on Ra isotopes in formation water and barite scale to explore natural controls on radioactivity. Our approach combined extensive compilations of published data, collection and analyses of new water samples and scale material, and geochemical modeling of scale Precipitation and Ra incorporation in barite.

Fisher, R.

1995-08-01T23:59:59.000Z

402

Development and Application of a Paleomagnetic/Geochemical Method for Constraining the Timing of Burial Diagenetic and Fluid  

SciTech Connect

Studies of diagenesis caused by fluid migration or other events are commonly hindered by a lack of temporal control. Our results to date demonstrate that a paleomagnetic/geochemical approach can be used to date fluid migration as well as burial diagenetic events. Our principal working hypothesis is that burial diagenetic processes (e.g., maturation of organic-rich sediments and clay diagenesis) and the migration of fluids can trigger the authigenesis of magnetic mineral phases. The ages of these events can be constrained by comparing chemical remanent magnetizations (CRMs) to independently established Apparent Polar Wander Paths. While geochemical (e.g. stable isotope and organic analyses) and petrographic studies provide important clues for establishing these relationships, the ultimate test of this hypothesis requires the application of independent dating methods to verify the paleomagnetic ages. Towards this end, we have used K-Ar dating of illitization as an alternative method for constraining the ages of magnetic mineral phases in our field areas.

Elmore, Richard D.; Engel, Michael H.

2005-03-10T23:59:59.000Z

403

Multielement geochemical exploration data for the Cove Fort-Sulphurdale Known Geothermal Resource Area, Beaver and Millard counties, Utah  

DOE Green Energy (OSTI)

Multielement geochemical exploration data have been acquired for the Cove Fort-Sulphurdale Known Geothermal Resource Area (KGRA). This was accomplished by analysis of both whole rock and +3.3 specific gravity concentrate samples from cuttings composites collected from shallow rotary drill holes. Areal distributions are reported for arsenic, mercury, lead and zinc. These are elements indicated by previous studies to be broadly zoned around thermal centers in geothermal systems and thus to be useful for selecting and prioritizing drilling targets. Results from this work suggest that reservoir temperature and/or reservoir to surface permeability, and thus possibly overall potential for a geothermal resource, increase northward beneath the approximately 18 square mile area containing shallow drill holes, possibly to beyond the northern limits of the area. The data provide a basis for development of three principal target models for the geothermal system but do not permit prioritization of these models. It is recommended that geochemical, geological, and temperature gradient surveys be expanded northward from the present survey area to more fully define the area which appears to have the best resource potential and to aid prioritization of the target models.

Bamford, R.W.; Christensen, O.D.

1979-09-01T23:59:59.000Z

404

Microbial community structure of hydrothermal deposits from geochemically different vent fields along the Mid-Atlantic Ridge  

Science Conference Proceedings (OSTI)

To evaluate the effects of local fluid geochemistry on microbial communities associated with active hydrothermal vent deposits, we examined the archaeal and bacterial communities of 12 samples collected from two very different vent fields: the basalt-hosted Lucky Strike (37 17'N, 32 16.3'W, depth 1600-1750 m) and the ultramafic-hosted Rainbow (36 13'N, 33 54.1'W, depth 2270-2330 m) vent fields along the Mid-Atlantic Ridge (MAR). Using multiplexed barcoded pyrosequencing of the variable region 4 (V4) of the 16S rRNA genes, we show statistically significant differences between the archaeal and bacterial communities associated with the different vent fields. Quantitative polymerase chain reaction (qPCR) assays of the functional gene diagnostic for methanogenesis (mcrA), as well as geochemical modelling to predict pore fluid chemistries within the deposits, support the pyrosequencing observations. Collectively, these results show that the less reduced, hydrogen-poor fluids at Lucky Strike limit colonization by strict anaerobes such as methanogens, and allow for hyperthermophilic microaerophiles, like Aeropyrum. In contrast, the hydrogen-rich reducing vent fluids at the ultramafic-influenced Rainbow vent field support the prevalence of methanogens and other hydrogen-oxidizing thermophiles at this site. These results demonstrate that biogeographical patterns of hydrothermal vent microorganisms are shaped in part by large scale geological and geochemical processes.

Flores, Gilberto E [Portland State University; Campbell, James H [ORNL; Kirshtein, Julie D [United States Geological Survey, Reston, VA; Meneghin, Jennifer [Portland State University; Podar, Mircea [ORNL; Steinberg, Joshua [Oregon Episcopal School, Portland, OR; Seewald, Jeffrey S [Woods Hole Oceanographic Institution (WHOI), Woods Hole, MA; Tivey, Margaret Kingston [Woods Hole Oceanographic Institution (WHOI), Woods Hole, MA; Voytek, Mary A [United States Geological Survey & National Aeronautics and Space Administration; Reysenbach, Anna-Louise [Portland State University; Yang, Zamin Koo [ORNL

2011-01-01T23:59:59.000Z

405

Method for generating a highly reactive plasma for exhaust gas aftertreatment and enhanced catalyst reactivity  

DOE Patents (OSTI)

A method for non-thermal plasma aftertreatment of exhaust gases the method comprising the steps of providing short risetime, high frequency, high power bursts of low-duty factor microwaves sufficient to generate a plasma discharge and passing a gas to be treated through the discharge so as to cause dissociative reduction of the exhaust gases and enhanced catalyst reactivity through application of the pulsed microwave fields directly to the catalyst material sufficient to cause a polarizability catastrophe and enhanced heating of the metal crystallite particles of the catalyst, and in the presence or absence of the plasma. The invention also includes a reactor for aftertreatment of exhaust gases.

Whealton, John H. (Oak Ridge, TN); Hanson, Gregory R. (Clinton, TN); Storey, John M. (Oak Ridge, TN); Raridon, Richard J. (Oak Ridge, TN); Armfield, Jeffrey S. (Ypsilanti, MI); Bigelow, Timothy S. (Knoxville, TN); Graves, Ronald L. (Knoxville, TN)

2002-01-01T23:59:59.000Z

406

Reactivity Control Schemes for Fast Spectrum Space Nuclear Reactors  

Science Conference Proceedings (OSTI)

Several different reactivity control schemes are considered for future space nuclear reactor power systems. Each of these control schemes uses a combination of boron carbide absorbers and/or beryllium oxide reflectors to achieve sufficient reactivity swing to keep the reactor subcritical during launch and to provide sufficient excess reactivity to operate the reactor over its expected 7–15 year lifetime. The size and shape of the control system directly impacts the size and mass of the space reactor's reflector and shadow shield

Aaron E. Craft; Jeffrey C. King

2008-01-01T23:59:59.000Z

407

Standard test methods for determining chemical durability of nuclear, hazardous, and mixed waste glasses and multiphase glass ceramics: The product consistency test (PCT)  

E-Print Network (OSTI)

1.1 These product consistency test methods A and B evaluate the chemical durability of homogeneous glasses, phase separated glasses, devitrified glasses, glass ceramics, and/or multiphase glass ceramic waste forms hereafter collectively referred to as “glass waste forms” by measuring the concentrations of the chemical species released to a test solution. 1.1.1 Test Method A is a seven-day chemical durability test performed at 90 ± 2°C in a leachant of ASTM-Type I water. The test method is static and conducted in stainless steel vessels. Test Method A can specifically be used to evaluate whether the chemical durability and elemental release characteristics of nuclear, hazardous, and mixed glass waste forms have been consistently controlled during production. This test method is applicable to radioactive and simulated glass waste forms as defined above. 1.1.2 Test Method B is a durability test that allows testing at various test durations, test temperatures, mesh size, mass of sample, leachant volume, a...

American Society for Testing and Materials. Philadelphia

2002-01-01T23:59:59.000Z

408

SAMFT3D: Single-phase and multiphase flow and transport in 3 dimensions. Version 1.0, Documentation and user`s guide  

Science Conference Proceedings (OSTI)

SAMFT3D is a three-dimensional, finite element code designed to simulate single-phase and multiphase fluid flow and contaminant transport in porous media. This report documents the single-phase version of the code. The single-phase computational modules have been developed to simulate flow and solute transport in fully or variable saturated porous media. The formulation of the governing equations and the numerical procedures used in these modules are presented. The flow equation is approximated using the Galerkin finite element method. For variably saturated flow problems, nonlinearities due to unsaturated soil properties are treated using Picard or Newton-Raphson iterations. The contaminant transport simulation can account for advection, hydrodynamic dispersion, linear equilibrium sorption, and first-order degradation. Transport of a single component can be handled. The transport equation is approximated using a upstream weighted residual method. Several test problems are presented to verify the code and to demonstrate its utility. These problems range from single one-dimensional to complex three-dimensional problems. This document has been produced as a user`s manual. It contains brief information on the code structure along with detailed instructions for input data preparation and sample input and printed output for selected test problems. Also included are instructions for setting up a simulation run and restart procedures.

NONE

1991-09-01T23:59:59.000Z

409

High-resolution numerical methods for compressible multi-phase flow in hierarchical porous media. Progress report, September 1993--September 1994  

SciTech Connect

This is the second year in the proposed three-year effort to develop high-resolution numerical methods for multi-phase flow in hierarchical porous media. The issues being addressed in this research are: Computational efficiency: Field-scale simulation of enhanced oil recovery, whether for energy production or aquifer remediation, is typically highly under-resolved. This is because rock transport properties vary on many scales, and because current numerical methods have low resolution. Effective media properties: Since porous media are formed through complex geologic processes, they involve significant uncertainty and scale-dependence. Given this uncertainty, knowledge of ensemble averages of flow in porous media can be preferable to knowledge of flow in specific realizations of the reservoir. However, current models of effective properties do not represent the observed behavior very well. Relative permeability models present a good example of this problem. In practice, these models seldom provide realistic representations of hysteresis, interfacial tension effects or three-phase flow; there are no models that represent well all three effects simultaneously.

Trangenstein, J.A.

1994-03-15T23:59:59.000Z

410

Assessment of the Economic Potential of Microgrids for Reactive Power Supply  

E-Print Network (OSTI)

of Commercial Building Microgrids,” IEEE Transactions onEconomic Potential of Microgrids for Reactive Power Supplyof creating an incentive for microgrids to provide reactive

Appen, Jan von

2012-01-01T23:59:59.000Z

411

Synthesis of Sm-Fe-N Hard Magnets by Reactive Mechanical Milling  

Science Conference Proceedings (OSTI)

In this study, we have performed reactive mechanical milling on Sm2Fe17 alloy under hydrogen atmosphere. After reactive mechanical milling, the Sm2Fe17 ...

412

Photo of the Week: Reactive Ion Etching | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Reactive Ion Etching Reactive Ion Etching Photo of the Week: Reactive Ion Etching October 17, 2013 - 1:26pm Addthis Have you ever heard of Laue lenses? These multilayer lenses are used to focus high-intensity x-ray beams to show the details of nano material structures. In this photo, the drop-like domes were carved through a process called reactive ion etching, which produced the striped bubbles you see in the Laue lens. The prototype in this image helped scientists perfect the process of creating lenses so precise that scientists are able to focus x-rays to within a single nanometer. | Photo courtesy of Brookhaven National Laboratory. Have you ever heard of Laue lenses? These multilayer lenses are used to focus high-intensity x-ray beams to show the details of nano material

413

Radiation Chemistry of Ionic Liquids: Reactivity of Primary Species  

NLE Websites -- All DOE Office Websites (Extended Search)

Liquids: Reactivity of Primary Species Liquids: Reactivity of Primary Species James F. Wishart In "Ionic Liquids as Green Solvents: Progress and Prospects" Rogers, R. D. and Seddon, K. R. , Eds.; ACS Symp. Ser. 856, Ch. 31, pp. 381-395, American Chemical Society, Washington, DC, 2003. (ISBN 0-84123-856-1) [Information about the book] Abstract: An understanding of the radiation chemistry of ionic liquids is important for development of their applications in radioactive material processing and for the application of pulse radiolysis techniques to the general study of chemical reactivity in ionic liquids. The distribution of primary radiolytic species and their reactivities determine the yields of ultimate products and the radiation stability of a particular ionic liquid. This chapter introduces some principles of radiation chemistry and the

414

A-26: Nanoindentation Investigation of the Reactive Pulsed Laser ...  

Science Conference Proceedings (OSTI)

... of the Reactive Pulsed Laser Deposited Superconducting Niobium Nitride Thin Films. Author(s) ... A-33: Modeling of a Displacive Transformation within Continuous ... Dye-Sensitized Solar Cells by Introducing a TiN Nanocrystalline Thin Film.

415

Pre-plated reactive diffusion-bonded battery electrode plaques  

SciTech Connect

A high strength, metallic fiber battery plaque is made using reactive diffusion bonding techniques, where a substantial amount of the fibers are bonded together by an iron-nickel alloy.

Maskalick, Nicholas J. (Pittsburgh, PA)

1984-01-01T23:59:59.000Z

416

Land Use and Reactive Nitrogen Discharge: Effects of Dietary Choices  

Science Conference Proceedings (OSTI)

Modern agriculture alters natural biological and geophysical processes, with magnitudes proportional to its spatial extent. Cultivation is also the main cause of artificially enhanced reactive nitrogen (Nr) availability in natural ecosystems. ...

Gidon Eshel; Pamela A. Martin; Esther E. Bowen

2010-12-01T23:59:59.000Z

417

Reactive Reserve Requirements and Optimal Allocation Among Resources  

Science Conference Proceedings (OSTI)

Voltage stability is a major concern in power system operation, and the need to maintain it limits power transfers in the prevailing open access environment. In a power system with significant induction motor loads, voltage instability can be manifested either in the form of delayed voltage recovery or voltage collapse. Inadequate reactive supply is a major factor in causing these problems. Reactive supply is an important ingredient in maintaining healthy power system voltages and facilitating power tran...

2010-12-01T23:59:59.000Z

418

(Electronic structure and reactivities of transition metal clusters)  

DOE Green Energy (OSTI)

The following are reported: theoretical calculations (configuration interaction, relativistic effective core potentials, polyatomics, CASSCF); proposed theoretical studies (clusters of Cu, Ag, Au, Ni, Pt, Pd, Rh, Ir, Os, Ru; transition metal cluster ions; transition metal carbide clusters; bimetallic mixed transition metal clusters); reactivity studies on transition metal clusters (reactivity with H{sub 2}, C{sub 2}H{sub 4}, hydrocarbons; NO and CO chemisorption on surfaces). Computer facilities and codes to be used, are described. 192 refs, 13 figs.

Not Available

1992-01-01T23:59:59.000Z

419

[Electronic structure and reactivities of transition metal clusters  

DOE Green Energy (OSTI)

The following are reported: theoretical calculations (configuration interaction, relativistic effective core potentials, polyatomics, CASSCF); proposed theoretical studies (clusters of Cu, Ag, Au, Ni, Pt, Pd, Rh, Ir, Os, Ru; transition metal cluster ions; transition metal carbide clusters; bimetallic mixed transition metal clusters); reactivity studies on transition metal clusters (reactivity with H{sub 2}, C{sub 2}H{sub 4}, hydrocarbons; NO and CO chemisorption on surfaces). Computer facilities and codes to be used, are described. 192 refs, 13 figs.

Not Available

1992-08-01T23:59:59.000Z

420

Microsoft Word - treact_manual.doc  

Office of Scientific and Technical Information (OSTI)

1 1 LBNL-55460 TOUGHREACT User's Guide: A Simulation Program for Non- isothermal Multiphase Reactive Geochemical Transport in Variably Saturated Geologic Media Tianfu Xu, Eric Sonnenthal, Nicolas Spycher , and Karsten Pruess Earth Sciences Division, Lawrence Berkeley National Laboratory University of California, Berkeley, CA 94720. May 2004 This work was supported by the Laboratory Directed Research and Development Program of the Ernest Orlando Lawrence Berkeley National Laboratory, and by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Geothermal Technologies, of the U.S. Department of Energy, under Contract No. DE-AC03-76SF00098. 2 i TABLE OF CONTENTS 1. INTRODUCTION ...........................................................................................................

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421

Reactive burn models and ignition & growth concept  

SciTech Connect

Plastic-bonded explosives are heterogeneous materials. Experimentally, shock initiation is sensitive to small amounts of porosity, due to the formation of hot spots (small localized regions of high temperature). This leads to the Ignition and Growth concept, introduced by Lee and Tarver in 1980, as the basis for reactive burn models. A homogeneized burn rate needs to account for three mesoscale physical effects (i) the density of burnt hot spots, which depends on the lead shock strength; (ii) the growth of the burn fronts triggered by hot spots, which depends on the local deflagration speed; (iii) a geometric factor that accounts for the overlap of deflagration wavelets from adjacent hot spots. These effects can be combined and the burn model defined by specifying the reaction progress variable {lambda}(t) as a function of a dimensionless reaction length {tau}{sub hs}(t)/{ell}{sub hs}, rather than by xpecifying an explicit burn rate. The length scale {ell}{sub hs} is the average distance between hot spots, which is proportional to [N{sub hs}(P{sub s})]{sup -1/3}, where N{sub hs} is the number density of hot spots activated by the lead shock. The reaction length {tau}{sub hs}(t) = {line_integral}{sub 0}{sup t} D(P(t'))dt' is the distance the burn front propagates from a single hot spot, where D is the deflagration speed and t is the time since the shock arrival. A key implementation issue is how to determine the lead shock strength in conjunction with a shock capturing scheme. They have developed a robust algorithm for this purpose based on the Hugoniot jump condition for the energy. The algorithm utilizes the time dependence of density, pressure and energy within each cell. The method is independent of the numerical dissipation used for shock capturing. It is local and can be used in one or more space dimensions. The burn model has a small number of parameters which can be calibrated to fit velocity gauge data from shock initiation experiments.

Menikoff, Ralph S [Los Alamos National Laboratory; Shaw, Milton S [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

422

Geochemical and hydrodynamic controls on arsenic and trace metal cycling in a seasonally stratified US sub-tropical reservoir  

SciTech Connect

The phase distribution of trace metals and oxyanions was investigated within a South Texas watershed hosting a high density of surface uranium mine pits and tailings. The objectives of the study were to evaluate the potential impact of these old uranium mining sites on the watershed with particular emphasis on spatial and temporal changes in water quality of a reservoir that serves as the major source of freshwater to a population of {approx} 350,000 people in the region. A livestock pond, bordered by uranium mine tailings, was used as a model case-study site to evaluate the cycling of uranium mine-derived oxyanions under changing redox conditions. Although the pond showed seasonal thermal and chemical stratification, geochemical cycling of metals was limited to Co and Pb, which seemed to be mostly associated with redox cycling of Mn mineral phases, and U, which suggested reductive precipitation in the ponds hypolimnion. Uranium levels, however, were too low to support strong inputs from th e tailings into the water column of the pond. The strong relations observed between particulate Cr, Cs, V and Fe suggest that these metals are associated with a stable particulate phase (probably allochthonous aluminosilicates) enriched in unreactive iron. This observation is supported by a parallel relationship in sediments collected across a broad range of sediment depositional processed (and histories) in the basin. Arsenic, though selectively enriched in the ponds water column, remained stable and mostly in solution throughout the depth of the profile and showed no sign of geochemical cycling or interaction with Fe-rich particles. We found no evidence of anthropogenic impacts of U mines beyond the purely local scale. Arsenic does decrease in concentration downstream of uranium mining sites but its presence within the Nueces drainage basin is related to interactions between surface and ground waters with uranium-rich geological formations rather than long-scale transport of contaminants downstream of the U mine pits and tailings. As in Lyssy pond, arsenic (and other oxyanions) in Lake Corpus Christi's water column are not affected by the abundant presence of Fe-rich particles but instead behave conservatively throughout the entire period of study. A quantitative mass balance model, constructed using monthly hydrological data for the reservoir, provides quantitative evidence of seasonal evaporative concentration of as in surface waters demonstrating the predominance of hydrodynamic constraints, over geochemical ones, on the cycling of this metal in selected aquatic systems.

Brandenberger, Jill M.; Louchouarn, Patrick; Herbert, Bruce; Tissot, Philippe

2004-10-01T23:59:59.000Z

423

The global geochemical cycles of iron and calcium: using novel isotope systems to understand weathering, global mass budgets, natural reaction rates, and paleoclimate  

E-Print Network (OSTI)

in the sedimentary column, and diagenetic alteration of Ca isotope signals over geologic time scales. The overallThe global geochemical cycles of iron and calcium: using novel isotope systems to understand of Doctor of Philosophy in Geology in the GRADUATE DIVISION of the UNIVERSITY OF CALIFORNIA, BERKELEY

Fantle, Matthew

424

Data Package of Samples Collected for Hydrogeologic and Geochemical Characterization: 300 Area RI/FS Sediment Cores  

Science Conference Proceedings (OSTI)

This is a data package for sediment samples received from the 300 FF 5 OU. This report was prepared for CHPRC. Between August 16, 2010 and April 25, 2011 sediment samples were received from 300-FF-5 for geochemical studies. The analyses for this project were performed at the 331 building located in the 300 Area of the Hanford Site. The analyses were performed according to Pacific Northwest National Laboratory (PNNL) approved procedures and/or nationally recognized test procedures. The data sets include the sample identification numbers, analytical results, estimated quantification limits (EQL), and quality control data. The preparatory and analytical quality control requirements, calibration requirements, acceptance criteria, and failure actions are defined in the on-line QA plan 'Conducting Analytical Work in Support of Regulatory Programs' (CAW). This QA plan implements the Hanford Analytical Services Quality Assurance Requirements Documents (HASQARD) for PNNL.

Lindberg, Michael J.; Bjornstad, Bruce N.; Lanigan, David C.; Williams, Benjamin D.

2011-05-01T23:59:59.000Z

425

KINETIC MODELING OF A FISCHER-TROPSCH REACTION OVER A COBALT CATALYST IN A SLURRY BUBBLE COLUMN REACTOR FOR INCORPORATION INTO A COMPUTATIONAL MULTIPHASE FLUID DYNAMICS MODEL  

DOE Green Energy (OSTI)

Currently multi-tubular fixed bed reactors, fluidized bed reactors, and slurry bubble column reactors (SBCRs) are used in commercial Fischer Tropsch (FT) synthesis. There are a number of advantages of the SBCR compared to fixed and fluidized bed reactors. The main advantage of the SBCR is that temperature control and heat recovery are more easily achieved. The SBCR is a multiphase chemical reactor where a synthesis gas, comprised mainly of H2 and CO, is bubbled through a liquid hydrocarbon wax containing solid catalyst particles to produce specialty chemicals, lubricants, or fuels. The FT synthesis reaction is the polymerization of methylene groups [-(CH2)-] forming mainly linear alkanes and alkenes, ranging from methane to high molecular weight waxes. The Idaho National Laboratory is developing a computational multiphase fluid dynamics (CMFD) model of the FT process in a SBCR. This paper discusses the incorporation of absorption and reaction kinetics into the current hydrodynamic model. A phased approach for incorporation of the reaction kinetics into a CMFD model is presented here. Initially, a simple kinetic model is coupled to the hydrodynamic model, with increasing levels of complexity added in stages. The first phase of the model includes incorporation of the absorption of gas species from both large and small bubbles into the bulk liquid phase. The driving force for the gas across the gas liquid interface into the bulk liquid is dependent upon the interfacial gas concentration in both small and large bubbles. However, because it is difficult to measure the concentration at the gas-liquid interface, coefficients for convective mass transfer have been developed for the overall driving force between the bulk concentrations in the gas and liquid phases. It is assumed that there are no temperature effects from mass transfer of the gas phases to the bulk liquid phase, since there are only small amounts of dissolved gas in the liquid phase. The product from the incorporation of absorption is the steady state concentration profile of the absorbed gas species in the bulk liquid phase. The second phase of the model incorporates a simplified macrokinetic model to the mass balance equation in the CMFD code. Initially, the model assumes that the catalyst particles are sufficiently small such that external and internal mass and heat transfer are not rate limiting. The model is developed utilizing the macrokinetic rate expression developed by Yates and Satterfield (1991). Initially, the model assumes that the only species formed other than water in the FT reaction is C27H56. Change in moles of the reacting species and the resulting temperature of the catalyst and fluid phases is solved simultaneously. The macrokinetic model is solved in conjunction with the species transport equations in a separate module which is incorporated into the CMFD code.

Anastasia Gribik; Doona Guillen, PhD; Daniel Ginosar, PhD

2008-09-01T23:59:59.000Z

426

Third (March 2006) Coring and Analysis of Zero-Valent Iron Permeable Reactive Barrier, Monticello, Utah  

Energy.gov (U.S. Department of Energy (DOE))

Third (March 2006) Coring and Analysis of Zero-Valent Iron Permeable Reactive Barrier, Monticello, Utah

427

Reactive behavior in object-oriented applications: an analysis and a research roadmap  

Science Conference Proceedings (OSTI)

Reactive applications are difficult to implement. Traditional solutions based on event systems and the Observer pattern have a number of inconveniences, but programmers bear them in return for the benefits of OO design. On the other hand, reactive approaches ... Keywords: functional-reactive programming, incremental computation, object-oriented programming, reactive programming

Guido Salvaneschi; Mira Mezini

2013-03-01T23:59:59.000Z

428

Ionic Liquids and Ionizing Radiation: Reactivity of Highly Energetic  

NLE Websites -- All DOE Office Websites (Extended Search)

Ionizing Radiation: Reactivity of Highly Energetic Ionizing Radiation: Reactivity of Highly Energetic Species James F. Wishart J. Phys. Chem. Lett. 1, 3225-3231 (2010). [Find paper at ACS Publications] or use ACS Articles on Request View the video on this Perspective article at The Journal of Physical Chemistry Letters (5:03) Selected for the ACS Special Virtual Issue on Ionic Liquids (March 2011). Abstract: Due to their unique properties, ionic liquids present many opportunities for basic research on the interactions of radiation with materials under conditions not previously available. At the same time, there are practical applied reasons for characterizing, understanding, and being able to predict how ionic-liquid-based devices and industrial-scale systems will perform under conditions of extreme reactivity, including radiation. This

429

Options for Control of Reactive Power by Distributed Photovoltaic Generators  

E-Print Network (OSTI)

High penetration levels of distributed photovoltaic(PV) generation on an electrical distribution circuit present several challenges and opportunities for distribution utilities. Rapidly varying irradiance conditions may cause voltage sags and swells that cannot be compensated by slowly responding utility equipment resulting in a degradation of power quality. Although not permitted under current standards for interconnection of distributed generation, fast-reacting, VAR-capable PV inverters may provide the necessary reactive power injection or consumption to maintain voltage regulation under difficult transient conditions. As side benefit, the control of reactive power injection at each PV inverter provides an opportunity and a new tool for distribution utilities to optimize the performance of distribution circuits, e.g. by minimizing thermal losses. We discuss and compare via simulation various design options for control systems to manage the reactive power generated by these inverters. An important design de...

Sulc, Petr; Backhaus, Scott; Chertkov, Michael

2010-01-01T23:59:59.000Z

430

Internal structure, hygroscopic and reactive properties of mixed sodium  

NLE Websites -- All DOE Office Websites (Extended Search)

Internal structure, hygroscopic and Internal structure, hygroscopic and reactive properties of mixed sodium methanesulfonate-sodium chloride particles Internal structure, hygroscopic and reactive properties of mixed sodium methanesulfonate-sodium chloride particles Print Friday, 13 May 2011 00:00 Scientists recently combined experimental approaches and molecular dynamics modeling to gain new insights into the internal structure of sea salt particles and relate it to their fundamental chemical reactivity in the atmosphere. This research shows that surface enhancement or depletion of chemical components in marine particles can occur because of the difference in the chemical nature of the species. Because the atmospheric chemistry of the salt particles takes place at the gas-particle interface, understanding their complex surfaces provides new insights about their effect on the environment and climate change. Article Link.

431

OPF for reactive pricing studies on the NGC system  

SciTech Connect

Retail transmission services like those being provided by the National Grid Company (NGC) in England and Wales pose new challenges for the pricing of reactive power supply. A reactive power market approach has been proposed by NGC and continues to be evaluated. Such an approach includes a novel requirement for transmission constrained economic dispatch of VArs, a problem in the security constrained optimal power flow (OPF) class. The problem formulations handled by the OPF package in use could not accommodate NGC`s requirements. This paper describes the reactive pricing problem being addressed, the modeling requirements, and the resulting extensions made to the OPF formulation and package. It discusses the test results obtained to date on the NGC system.

Dandachi, N.H.; Rawlins, M.J. [National Grid Co., Sindlesham (United Kingdom). Control Technology Centre; Alsac, O.; Prais, M.; Stott, B. [PCA Corp., Mesa, AZ (United States)

1996-02-01T23:59:59.000Z

432

Method and apparatus for measuring reactivity of fissile material  

DOE Patents (OSTI)

Given are a method and apparatus for measuring nondestructively and noninvasively (i.e., using no internal probing) the burnup, reactivity, or fissile content of any material which emits neutrons and which has fissionable components. The assay is accomplished by altering the return flux of neutrons into the fuel assembly by means of changing the reflecting material. The existing passive neutron emissions in the material being assayed are used as the source of interrogating neutrons. Two measurements of either emitted neutron or emitted gamma-ray count rates are made and are then correlated to either reactivity, burnup, or fissionable content of the material being assayed, thus providing a measurement of either reactivity, burnup, or fissionable content of the material being assayed. Spent fuel which has been freshly discharged from a reactor can be assayed using this method and apparatus. Precisions of 1000 MWd/tU appear to be feasible.

Lee, D.M.; Lindquist, L.O.

1982-09-07T23:59:59.000Z

433

Effect of superbanana diffusion on fusion reactivity in stellarators  

Science Conference Proceedings (OSTI)

Fusion reactivity is usually obtained using a Maxwellian distribution. However, energy-dependent radial diffusion can modify the energy distribution. Superbanana diffusion is energy