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Title: Laboratory Investigations in Support of Carbon Dioxide-Limestone Sequestration in the Ocean

Abstract

This semi-annual progress reports includes further findings on CO{sub 2}-in-Water (C/W) emulsions stabilized by fine particles. In previous semi-annual reports we described the formation of stable C/W emulsions using pulverized limestone (CaCO{sub 3}), flyash, beach sand, shale and lizardite, a rock rich in magnesium silicate. For the creation of these emulsions we used a High-Pressure Batch Reactor (HPBR) equipped with view windows for illumination and video camera recording. For deep ocean sequestration, a C/W emulsion using pulverized limestone may be the most suitable. (a) Limestone (mainly CaCO{sub 3}) is cheap and plentiful; (b) limestone is innocuous for marine organisms (in fact, it is the natural ingredient of shells and corals); (c) it buffers the carbonic acid that forms when CO{sub 2} dissolves in water. For large-scale sequestration of a CO{sub 2}/H{sub 2}O/CaCO{sub 3} emulsion a device is needed that mixes the ingredients, liquid carbon dioxide, seawater, and a slurry of pulverized limestone in seawater continuously, rather than incrementally as in a batch reactor. A practical mixing device is a Kenics-type static mixer. The static mixer has no moving parts, and the shear force for mixing is provided by the hydrostatic pressure of liquid CO{sub 2} and CaCO{sub 3} slurry inmore » the delivery pipes from the shore to the disposal depth. This semi-annual progress report is dedicated to the description of the static mixer and the results that have been obtained using a bench-scale static mixer for the continuous formation of a CO{sub 2}/H{sub 2}O/CaCO{sub 3} emulsion. The static mixer has an ID of 0.63 cm, length 23.5 cm, number of baffles 27. Under pressure, a slurry of CaCO{sub 3} in artificial seawater (3.5% by weight NaCl) and liquid CO{sub 2} are co-injected into the mixer. From the mixer, the resulting emulsion flows into a Jerguson cell with two oblong windows on opposite sides, then it is vented. A fully ported ball valve inserted after the Jerguson cell allows the emulsion to be stopped in the cell. In such a manner the emulsion can be photographed while it is flowing through the cell, or after it has stagnated in the cell. A slurry of 10 g/L CaCO{sub 3} (Sigma Chemicals C-4830 reagent grade) in artificial seawater, co-injected into the static mixer at a rate of 1.5 L/min with liquid CO{sub 2} at a rate of 150 mL/min, at temperature 5-10 C, pressure 10 MPa, produced an emulsion with mean globule diameter in the 70-100 {micro}m range. In a HPBR, using the same materials, proportions, temperature and pressure, mixed with a magnetic stir bar at 1300 rpm, the mean globule diameter is in the 200-300 {micro}m range. Evidently, the static mixer produces an emulsion with smaller globule diameters and narrower distribution of globule diameters than a batch reactor.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
University of Massachusetts Lowell
Sponsoring Org.:
USDOE
OSTI Identifier:
861379
DOE Contract Number:
FC26-02NT41441
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; CARBON DIOXIDE; CALCIUM CARBONATES; CARBON SEQUESTRATION; MARINE DISPOSAL; MIXERS; DESIGN; PERFORMANCE; SEAWATER; SLURRIES; EMULSIONS

Citation Formats

Dan Golomb, Eugene Barry, David Ryan, Carl Lawton, Stephen Pennell, Peter Swett, Huishan Duan, and Michael Woods. Laboratory Investigations in Support of Carbon Dioxide-Limestone Sequestration in the Ocean. United States: N. p., 2005. Web. doi:10.2172/861379.
Dan Golomb, Eugene Barry, David Ryan, Carl Lawton, Stephen Pennell, Peter Swett, Huishan Duan, & Michael Woods. Laboratory Investigations in Support of Carbon Dioxide-Limestone Sequestration in the Ocean. United States. doi:10.2172/861379.
Dan Golomb, Eugene Barry, David Ryan, Carl Lawton, Stephen Pennell, Peter Swett, Huishan Duan, and Michael Woods. Tue . "Laboratory Investigations in Support of Carbon Dioxide-Limestone Sequestration in the Ocean". United States. doi:10.2172/861379. https://www.osti.gov/servlets/purl/861379.
@article{osti_861379,
title = {Laboratory Investigations in Support of Carbon Dioxide-Limestone Sequestration in the Ocean},
author = {Dan Golomb and Eugene Barry and David Ryan and Carl Lawton and Stephen Pennell and Peter Swett and Huishan Duan and Michael Woods},
abstractNote = {This semi-annual progress reports includes further findings on CO{sub 2}-in-Water (C/W) emulsions stabilized by fine particles. In previous semi-annual reports we described the formation of stable C/W emulsions using pulverized limestone (CaCO{sub 3}), flyash, beach sand, shale and lizardite, a rock rich in magnesium silicate. For the creation of these emulsions we used a High-Pressure Batch Reactor (HPBR) equipped with view windows for illumination and video camera recording. For deep ocean sequestration, a C/W emulsion using pulverized limestone may be the most suitable. (a) Limestone (mainly CaCO{sub 3}) is cheap and plentiful; (b) limestone is innocuous for marine organisms (in fact, it is the natural ingredient of shells and corals); (c) it buffers the carbonic acid that forms when CO{sub 2} dissolves in water. For large-scale sequestration of a CO{sub 2}/H{sub 2}O/CaCO{sub 3} emulsion a device is needed that mixes the ingredients, liquid carbon dioxide, seawater, and a slurry of pulverized limestone in seawater continuously, rather than incrementally as in a batch reactor. A practical mixing device is a Kenics-type static mixer. The static mixer has no moving parts, and the shear force for mixing is provided by the hydrostatic pressure of liquid CO{sub 2} and CaCO{sub 3} slurry in the delivery pipes from the shore to the disposal depth. This semi-annual progress report is dedicated to the description of the static mixer and the results that have been obtained using a bench-scale static mixer for the continuous formation of a CO{sub 2}/H{sub 2}O/CaCO{sub 3} emulsion. The static mixer has an ID of 0.63 cm, length 23.5 cm, number of baffles 27. Under pressure, a slurry of CaCO{sub 3} in artificial seawater (3.5% by weight NaCl) and liquid CO{sub 2} are co-injected into the mixer. From the mixer, the resulting emulsion flows into a Jerguson cell with two oblong windows on opposite sides, then it is vented. A fully ported ball valve inserted after the Jerguson cell allows the emulsion to be stopped in the cell. In such a manner the emulsion can be photographed while it is flowing through the cell, or after it has stagnated in the cell. A slurry of 10 g/L CaCO{sub 3} (Sigma Chemicals C-4830 reagent grade) in artificial seawater, co-injected into the static mixer at a rate of 1.5 L/min with liquid CO{sub 2} at a rate of 150 mL/min, at temperature 5-10 C, pressure 10 MPa, produced an emulsion with mean globule diameter in the 70-100 {micro}m range. In a HPBR, using the same materials, proportions, temperature and pressure, mixed with a magnetic stir bar at 1300 rpm, the mean globule diameter is in the 200-300 {micro}m range. Evidently, the static mixer produces an emulsion with smaller globule diameters and narrower distribution of globule diameters than a batch reactor.},
doi = {10.2172/861379},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Nov 01 00:00:00 EST 2005},
month = {Tue Nov 01 00:00:00 EST 2005}
}

Technical Report:

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  • In the first half of the second contractual year the High Pressure Flow Reactor (HPFR) was fully designed. Most components have been ordered, and assembly of the flow reactor has been started. Also, the High Pressure Batch Reactor (HPBR) was redesigned for more efficient operation and observation of the emulsion of liquid or supercritical CO{sub 2} dispersed in water stabilized by pulverized limestone and other particles. In this period we firmly established that when about equal volumes of liquid CO{sub 2} and a slurry of pulverized limestone (CaCO{sub 3}) in de-ionized or artificial seawater (3.5% NaCl solution in de-ionized water)more » are thoroughly mixed, a macro-emulsion ensues consisting of liquid CO{sub 2} droplets coated with a sheath of CaCO{sub 3} particles dispersed in water. We call the coated CO{sub 2} droplets globules, and the macro-emulsion a globulsion. Depending on the degree of mixing (rotational speed of the magnetic stir bar) and the size of the CaCO{sub 3} particles, the globules float on top of the water column, are suspended in it, or sink to the bottom of the water column. With CO{sub 2} droplet diameter in the 100-200 {micro}m range, and CaCO{sub 3} particles in the 6-20 {micro}m range, most of the globules sink to the bottom. The formation of sinking globules is desirable for ocean sequestration of CO{sub 2}. The properties and stability of the globules will be further investigated in the HPFR in the second contractual year. It has also been demonstrated that flyash can be substituted for pulverized limestone to obtain a stable globulsion of CO{sub 2}-in-water.« less
  • In the second half of the second contractual year the construction of the High Pressure Flow Reactor (HPFR) was completed, tested, and satisfactory results have been obtained. The major component of the HPFR is a Kenics-type static mixer in which two fluids are thoroughly mixed. In our case the two fluids are liquid or supercritical CO{sub 2} and a slurry of pulverized limestone (CaCO{sub 3}) in pure or artificial seawater. The outflow from the static mixer is an emulsion consisting of CO{sub 2} droplets coated with a sheath of CaCO{sub 3} particles dispersed in water. The coated CO{sub 2} dropletsmore » are called globules, and the emulsion is called globulsion. By adjusting the proportions of the two fluids, carbon dioxide and water, the length and pressure drop across the static mixer, globules with a fairly uniform distribution of diameters can be obtained. By using different particle sizes of CaCO{sub 3}, globules can be obtained that are lighter or heavier than water, thus floating or sinking in a water column. The globulsion ensuing from the static mixer flows into a high pressure cell with windows, where the properties of the globules can be observed, such as their diameter and settling velocity. Using the Stokes' equation, the specific gravity of the globules can be determined. Also, a second generation High Pressure Batch Reactor (HPBR) was constructed. This reactor allows better mixing of the ingredients, more accurate temperature and pressure control, better illumination and video camera observations. In this reactor we established that CO{sub 2}-in-water globulsions can be formed stabilized by other particles than pulverized limestone. So far, we used flyash obtained from a local coal-fired power plant, and a pulverized magnesium silicate mineral, lizardite, Mg{sub 3}Si{sub 2}O{sub 5}(OH){sub 4}, obtained from DOE's Albany Research Laboratory. In the reporting period we conducted joint experiments in NETL's high pressure water tunnel facility. Thanks to the longer travel path of the globules, and the excellent optical instrumentation available at NETL, we were able to more accurately obtain globule diameters and settling velocities.« less
  • This semi-annual progress reports includes further findings on CO{sub 2}-in-Water (C/W) emulsions stabilized by fine particles. In previous reports we described C/W emulsions using pulverized limestone (CaCO{sub 3}), flyash, and a pulverized magnesium silicate mineral, lizardite, Mg{sub 3}Si{sub 2}O{sub 5}(OH){sub 4}, which has a similar composition as the more abundant mineral, serpentine. All these materials formed stable emulsions consisting of droplets of liquid or supercritical CO{sub 2} coated with a sheath of particles dispersed in water. During this semi-annual period we experimented with pulverized beach sand (10-20 {micro}m particle diameter). Pulverized sand produced an emulsion similar to the previously usedmore » materials. The globules are heavier than water, thus they accumulate at the bottom of the water column. Energy Dispersive X-ray (EDX) analysis revealed that the sand particles consisted mainly of SiO{sub 2}. Sand is one of the most abundant materials on earth, so the economic and energy penalties of using it for ocean sequestration consist mainly of the cost of transporting the sand to the user, the capital and operating costs of the pulverizer, and the energy expenditure for mining, shipping and grinding the sand. Most likely, sand powder would be innocuous to marine organisms if released together with CO{sub 2} in the deep ocean. We examined the effects of methanol (MeOH) and monoethanolamine (MEA) on emulsion formation. These solvents are currently used for pre- and post-combustion capture of CO{sub 2}. A fraction of the solvents may be captured together with CO{sub 2}. A volume fraction of 5% of these solvents in a mix of CO{sub 2}/CaCO{sub 3}/H{sub 2}O had no apparent effect on emulsion formation. Previously we have shown that a 3.5% by weight of common salt (NaCl) in water, simulating seawater, also had no appreciable effect on emulsion formation. We investigated the formation of inverted emulsions, where water droplets coated with pulverized materials are dispersed in liquid or supercritical CO{sub 2}. This is a Water-in-CO{sub 2} emulsion (W/C) stabilized by particles. For a W/C emulsion it is necessary to employ hydrophobic particles, where the particles are primarily wetted by CO{sub 2}. We used the following hydrophobic particles: carbon black, coal dust, and Teflon. All materials were either obtained as fine particles or ground to 10-20 {micro}m size. All these hydrophobic particles produced a stable W/C emulsion.« less
  • This semi-annual progress reports includes further findings on CO{sub 2}-in-Water emulsions stabilized by fine particles of limestone (CaCO{sub 3}). Specifically, here we report on the tests performed in the DOE National Energy Technology Laboratory High Pressure Water Tunnel Facility (HPWTF) using a Kenics-type static mixer for the formation of a CO{sub 2}-H{sub 2}O emulsion stabilized by fine particles of CaCO{sub 3}. The tested static mixer has an ID of 0.5 cm, length 23.5 cm, number of baffles 27. Under pressure, a slurry of CaCO{sub 3} particles (mean particle size 6 {micro}m) in reverse osmosis (RO) water and liquid CO{sub 2}more » were co-injected into the mixer. From the mixer, the resulting emulsion flowed into the HPWTF, which was filled with RO water kept at 6.8 MPa pressure and 4, 8 or 12 C. The emulsion plume was photographed by three video cameras through spy windows mounted on the wall of the HPWTF. The mixer produced an emulsion consisting of tiny CO{sub 2} droplets sheathed with a layer of CaCO{sub 3} particles dispersed in water. The sheathed droplets are called globules. The globules diameter was measured to be in the 300-500 {micro}m range. The globules were sinking in the HPWTF, indicating that they are heavier than the ambient water. The tests in the HPWTF confirmed that the Kenics-type static mixer is an efficient device for forming a CO{sub 2}-H{sub 2}O emulsion stabilized by fine particles of CaCO{sub 3}. The static mixer may prove to be a practical device for sequestering large quantities of CO{sub 2} in the deep ocean in the form of a CO{sub 2}-H{sub 2}O-CaCO{sub 3} emulsion. The static mixer can be mounted at the end of pipelines feeding the mixer. The static mixer has no moving parts. The pressure drop across the mixer that is necessary to sustain good mixing is created by the hydrostatic pressure of liquid CO{sub 2} and the slurry of CaCO{sub 3} in the pipes that feed the mixer. The tests in the HPWTF demonstrated that the emulsion plume is heavier than ambient seawater, hence the plume will sink to greater depth from the release point. Preliminary modeling indicates that an emulsion plume released at 500 m depth (the minimum depth required to prevent liquid CO{sub 2} flashing into vapor) may sink hundreds of meters before the plume comes to rest in the density stratified ocean water. Furthermore, tests in our laboratory showed that the emulsion is slightly alkaline, not acidic, because of the excess of CaCO{sub 3} particles present in the plume. Thus, the release of the CO{sub 2}-H{sub 2}OCaCO{sub 3} emulsion in the deep ocean is not likely to acidify the seawater around the release point. The possible acidification of seawater is the major environmental hazard if pure liquid CO{sub 2} were released in the deep ocean.« less
  • Research under this Project has proven that liquid carbon dioxide can be emulsified in water by using very fine particles as emulsion stabilizers. Hydrophilic particles stabilize a CO{sub 2}-in-H{sub 2}O (C/W) emulsion; hydrophobic particles stabilize a H{sub 2}O-in-CO{sub 2} (W/C) emulsion. The C/W emulsion consists of tiny CO{sub 2} droplets coated with hydrophilic particles dispersed in water. The W/C emulsion consists of tiny H{sub 2}O droplets coated with hydrophobic particles dispersed in liquid carbon dioxide. The coated droplets are called globules. The emulsions could be used for deep ocean sequestration of CO{sub 2}. Liquid CO{sub 2} is sparsely soluble inmore » water, and is less dense than seawater. If neat, liquid CO{sub 2} were injected in the deep ocean, it is likely that the dispersed CO{sub 2} droplets would buoy upward and flash into vapor before the droplets dissolve in seawater. The resulting vapor bubbles would re-emerge into the atmosphere. On the other hand, the emulsion is denser than seawater, hence the emulsion plume would sink toward greater depth from the injection point. For ocean sequestration a C/W emulsion appears to be most practical using limestone (CaCO{sub 3}) particles of a few to ten ?m diameter as stabilizing agents. A mix of one volume of liquid CO{sub 2} with two volumes of H{sub 2}O, plus 0.5 weight of pulverized limestone per weight of liquid CO{sub 2} forms a stable emulsion with density 1087 kg m{sup -3}. Ambient seawater at 500 m depth has a density of approximately 1026 kg m{sup -3}, so the emulsion plume would sink by gravity while entraining ambient seawater till density equilibrium is reached. Limestone is abundant world-wide, and is relatively cheap. Furthermore, upon disintegration of the emulsion the CaCO{sub 3} particles would partially buffer the carbonic acid that forms when CO{sub 2} dissolves in seawater, alleviating some of the concerns of discharging CO{sub 2} in the deep ocean. Laboratory experiments showed that the CaCO{sub 3} emulsion is slightly alkaline, not acidic. We tested the release of the CO{sub 2}-in-H{sub 2}O emulsion stabilized by pulverized limestone in the DOE National Energy Technology Laboratory High Pressure Water Tunnel Facility (HPWTF). Digital photographs showed the sinking globules in the HPWTF, confirming the concept of releasing the emulsion in the deep ocean. We modeled the release of an emulsion from the CO{sub 2} output of a 1000 MW coal-fired power plant at 500 m depth. The emulsion would typically sink several hundred meters before density equilibration with ambient seawater. The CO{sub 2} globules would rain out from the equilibrated plume toward the ocean bottom where they would disintegrate due to wave action and bottom friction. Conceptual release systems are described both for an open ocean release and a sloping seabed release of the emulsion.« less