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Title: Thermodynamic properties of hydrocarbon liquids at high pressures and temperatures

Abstract

Understanding the organic/inorganic interface in the Earth's crust requires values of the thermodynamic properties of hydrocarbon species in crude oil, coal, and natural gas at elevated temperatures and pressures. Values of the apparent standard partial molal Gibbs free energies and enthalpies of formation and the standard partial molal entropies and heat capacities of these organic species can be computed as a function of temperature at 1 bar using the equations of state adopted by Helgeson et al (1991). The pressure dependence of the thermodynamic properties can be calculated from a modified version of the Parameters From Group Contributions (PFGC) equation of state. To improve the accuracy of these predictions, critical evaluation of high-pressure density experiments reported in the literature was used in the present study to characterize b[sub j] as a function of pressure and temperature. The revised PFGC equation of state permits accurate calculation of the standard partial molal volumes of the major hydrocarbon species in the aliphatic, aromatic, and naphthenic fractions of crude oil, as well as fatty acids, phenols, and naphthenic acids at temperatures and pressures to 500 C and 5 kbar. Combining the revised PFGC equation of state and parameters with the standard partial molal propertiesmore » of these species at one bar and those of aqueous species and minerals permits calculation of the apparent standard partial molal Gibbs Free energies of reaction, and thus equilibrium constants for a wide variety of chemical equilibria among organic liquids, solids, and gases, aqueous species, and minerals at temperatures and pressures characteristic of both diagenetic and low-grade metamorphic processes in the Earth's crust.« less

Authors:
 [1];  [2];  [3]
  1. Univ. of Oslo (Norway). Dept. of Geology
  2. Univ. Paul Sabatier, Toulouse (France). Lab. de Geochimie
  3. Univ. of California, Berkeley, CA (United States). Dept. of Geology and Geophysics
Publication Date:
OSTI Identifier:
5905979
Report Number(s):
CONF-921058-
Journal ID: ISSN 0016-7592; CODEN: GAAPBC
Resource Type:
Conference
Journal Name:
Geological Society of America, Abstracts with Programs; (United States)
Additional Journal Information:
Journal Volume: 24:7; Conference: 1992 annual meeting of the Geological Society of America (GSA), Cincinnati, OH (United States), 26-29 Oct 1992; Journal ID: ISSN 0016-7592
Country of Publication:
United States
Language:
English
Subject:
02 PETROLEUM; 03 NATURAL GAS; 01 COAL, LIGNITE, AND PEAT; COAL; THERMODYNAMIC PROPERTIES; NATURAL GAS; PETROLEUM; CONTINENTAL CRUST; DIAGENESIS; ENTROPY; EQUATIONS OF STATE; FORMATION FREE ENERGY; FREE ENTHALPY; METAMORPHISM; RESERVOIR PRESSURE; RESERVOIR TEMPERATURE; SPECIFIC HEAT; CARBONACEOUS MATERIALS; EARTH CRUST; ENERGY; ENERGY SOURCES; EQUATIONS; FLUIDS; FOSSIL FUELS; FREE ENERGY; FUEL GAS; FUELS; GAS FUELS; GASES; MATERIALS; PHYSICAL PROPERTIES; 023000* - Petroleum- Properties & Composition; 033000 - Natural Gas- Properties & Composition; 010600 - Coal, Lignite, & Peat- Properties & Composition

Citation Formats

Aagaard, P, Oelkers, E H, and Helgeson, H C. Thermodynamic properties of hydrocarbon liquids at high pressures and temperatures. United States: N. p., 1992. Web.
Aagaard, P, Oelkers, E H, & Helgeson, H C. Thermodynamic properties of hydrocarbon liquids at high pressures and temperatures. United States.
Aagaard, P, Oelkers, E H, and Helgeson, H C. Wed . "Thermodynamic properties of hydrocarbon liquids at high pressures and temperatures". United States.
@article{osti_5905979,
title = {Thermodynamic properties of hydrocarbon liquids at high pressures and temperatures},
author = {Aagaard, P and Oelkers, E H and Helgeson, H C},
abstractNote = {Understanding the organic/inorganic interface in the Earth's crust requires values of the thermodynamic properties of hydrocarbon species in crude oil, coal, and natural gas at elevated temperatures and pressures. Values of the apparent standard partial molal Gibbs free energies and enthalpies of formation and the standard partial molal entropies and heat capacities of these organic species can be computed as a function of temperature at 1 bar using the equations of state adopted by Helgeson et al (1991). The pressure dependence of the thermodynamic properties can be calculated from a modified version of the Parameters From Group Contributions (PFGC) equation of state. To improve the accuracy of these predictions, critical evaluation of high-pressure density experiments reported in the literature was used in the present study to characterize b[sub j] as a function of pressure and temperature. The revised PFGC equation of state permits accurate calculation of the standard partial molal volumes of the major hydrocarbon species in the aliphatic, aromatic, and naphthenic fractions of crude oil, as well as fatty acids, phenols, and naphthenic acids at temperatures and pressures to 500 C and 5 kbar. Combining the revised PFGC equation of state and parameters with the standard partial molal properties of these species at one bar and those of aqueous species and minerals permits calculation of the apparent standard partial molal Gibbs Free energies of reaction, and thus equilibrium constants for a wide variety of chemical equilibria among organic liquids, solids, and gases, aqueous species, and minerals at temperatures and pressures characteristic of both diagenetic and low-grade metamorphic processes in the Earth's crust.},
doi = {},
journal = {Geological Society of America, Abstracts with Programs; (United States)},
issn = {0016-7592},
number = ,
volume = 24:7,
place = {United States},
year = {1992},
month = {1}
}

Conference:
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