WO2001074472A1 - Methods of selectively separating co2 from a multicomponent gaseous stream using co2 hydrate promoters - Google Patents

Methods of selectively separating co2 from a multicomponent gaseous stream using co2 hydrate promoters Download PDF

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Publication number
WO2001074472A1
WO2001074472A1 PCT/US2001/009465 US0109465W WO0174472A1 WO 2001074472 A1 WO2001074472 A1 WO 2001074472A1 US 0109465 W US0109465 W US 0109465W WO 0174472 A1 WO0174472 A1 WO 0174472A1
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Prior art keywords
gaseous stream
hydrate
multicomponent
promoter
multicomponent gaseous
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PCT/US2001/009465
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French (fr)
Inventor
Dwain F. Spencer
Robert P. Currier
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Univ California
Spencer Dwain F
Currier Robert P
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Application filed by Univ California, Spencer Dwain F, Currier Robert P filed Critical Univ California
Priority to JP2001572204A priority Critical patent/JP2003528721A/en
Priority to EP01924300A priority patent/EP1283740A4/en
Publication of WO2001074472A1 publication Critical patent/WO2001074472A1/en

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    • CCHEMISTRY; METALLURGY
    • C10PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10KPURIFYING OR MODIFYING THE CHEMICAL COMPOSITION OF COMBUSTIBLE GASES CONTAINING CARBON MONOXIDE
    • C10K1/00Purifying combustible gases containing carbon monoxide
    • C10K1/08Purifying combustible gases containing carbon monoxide by washing with liquids; Reviving the used wash liquors
    • C10K1/10Purifying combustible gases containing carbon monoxide by washing with liquids; Reviving the used wash liquors with aqueous liquids
    • C10K1/101Purifying combustible gases containing carbon monoxide by washing with liquids; Reviving the used wash liquors with aqueous liquids with water only
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D53/00Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • B01D53/1456Removing acid components
    • B01D53/1475Removing carbon dioxide
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02CCAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
    • Y02C20/00Capture or disposal of greenhouse gases
    • Y02C20/40Capture or disposal of greenhouse gases of CO2
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00Technologies relating to chemical industry
    • Y02P20/151Reduction of greenhouse gas [GHG] emissions, e.g. CO2

Definitions

  • the field of this invention is selective absorption of CO 2 gas.
  • the carbon monoxide is converted to hydrogen and additional CO 2 via the water-gas shift process. It is then often desirable to separate the CO 2 from the hydrogen to obtain a pure H 2 stream for subsequent use, e.g. as a fuel or feedstock.
  • CO 2 As man made CO 2 is increasingly viewed as a pollutant, another area in which it is desirable to separate CO 2 from a multicomponent gaseous stream is in the area of pollution control. Emissions from industrial facilities, such as manufacturing and power generation facilities, often include CO 2 . In such instances, it is often desirable to at least reduce the CO 2 concentration of the emissions. The CO 2 may be removed prior to combustion in some cases and post combustion in others.
  • a variety of processes have been developed for removing or isolating a particular gaseous component from a multicomponent gaseous stream. These processes include cryogenic fractionation, selective adsorption by solid adsorbents, gas absorption, and the like.
  • gas absorption processes solute gases are separated from gaseous mixtures by transport into a liquid solvent.
  • the liquid solvent ideally offers specific or selective solubility for the solute gas or gases to be separated.
  • CO 2 from effluent flue gas generated by a power plant often requires 25 to 30 % of the available energy generated by the plant. In most situations, this energy requirement, as well as the additional cost for removing the CO 2 from the flue gas, is prohibitive.
  • Patents disclosing methods of selectively removing one or more components from a multicomponent gaseous stream include: 3,150,942; 3,359,744; 3,479,298; 3,838,553;
  • Methods are provided for the selective removal of CO 2 from a multicomponent gaseous stream to provide a CO 2 depleted gaseous stream having at least a reduction, e.g. 20%, in the concentration of CO 2 relative to the untreated multicomponent gaseous stream.
  • the multicomponent gaseous stream is contacted with an aqueous fluid, e.g. CO 2 nucleated (or structured) water, under conditions of selective CO 2 clathrate formation to produce a CO2 clathrate slurry and CO2 depleted gaseous stream.
  • an aqueous fluid e.g. CO 2 nucleated (or structured) water
  • the CO2 hydrate promoter serves to desirably modulate the thermodynamic conditions of hydrate formation, e.g., by reducing the minimum CO 2 partial pressure required for formation of CO 2 containing hydrates (i.e. CO 2 hydrates) and/or increasing the temperature at which hydrate formation occurs, as compared to a control using pure CO 2 gas and water.
  • the promoter also serves to increase the kinetics of hydrate formation.
  • the subject methods find use in a variety of applications where it is desired to selectively remove CO 2 from a multicomponent gaseous stream.
  • Methods are provided for the selective removal of CO2 from a multicomponent gaseous stream to provide a CO 2 depleted gaseous stream having at least a reduction, e.g. 30 to 90%, in the concentration of CO 2 relative to the untreated multicomponent gaseous stream.
  • the multicomponent gaseous stream is contacted with an aqueous fluid, e.g. CO 2 nucleated (or structure) water, under conditions of selective CO 2 clathrate formation to produce a CO 2 clathrate slurry and CO 2 depleted gaseous stream.
  • an aqueous fluid e.g. CO 2 nucleated (or structure) water
  • a feature of the subject invention is that a CO 2 hydrate promoter is employed, where the CO 2 hydrate promoter is included in the multicomponent gaseous stream and/or the aqueous fluid.
  • the CO 2 hydrate promoter serves to desirably modulate the thermodynamic conditions of hydrate formation, e.g., by reducing the minimum CO 2 partial pressure required for formation of CO 2 containing hydrates (i.e. CO 2 hydrates) and/or increasing the temperature at which hydrate formation occurs, as compared to a control using pure CO 2 gas and water.
  • the promoter also serves to increase the kinetics of hydrate formation.
  • the subject methods find use in a variety of applications where it is desired to selectively remove CO 2 from a multicomponent gaseous stream.
  • the subject invention provides a method of selectively removing CO 2 from multicomponent gaseous stream, where a feature of the subject methods is the use of a CO 2 hydrate promoter.
  • the CO2 hydrate promoter may be present in the multicomponent gaseous stream and/or in CO2 nucleated or non-nucleated water (hydrate precursor solution).
  • the first step is to provide a multicomponent gaseous stream that includes a CO 2 hydrate promoter and/or an aqueous fluid, e.g. CO2 nucleated or non- nucleated water (water source), that includes a CO 2 hydrate promoter.
  • a multicomponent gaseous stream and/or CO2 nucleated water source is provided that includes an amount of a CO2 hydrate promoter that is sufficient to desirably modulate the thermodynamic conditions of hydrate formation, e.g., to reduce the CO 2 partial pressure requirement of hydrate formation under a given set of conditions, e.g. at or near 0°C, as compared to a control and/or to increase the temperature of hydrate formation.
  • CO2 partial pressure requirement of hydrate formation is meant the CO 2 partial pressure in the multicomponent gaseous stream that is required for CO 2 hydrate formation to occur upon contact with an aqueous fluid under a given set of conditions, such as the ones described in greater detail, infra.
  • the amount of CO 2 hydrate promoter that is present in the multicomponent gaseous stream and/or CO2 nucleated water is generally sufficient to provide for a reduction in the CO 2 partial pressure requirement of hydrate formation of at least about 20 %, usually at least about 30 % and more usually at least about 60 % as compared to a control (i.e.
  • the CO 2 partial pressure requirement of hydrate formation in the absence of the CO2 hydrate promoter under otherwise identical conditions where in certain embodiments the magnitude of the reduction may be as great as 85, 90 or 95% or more.
  • the CO 2 partial pressure requirement at 0°C in the presence of a sufficient amount of CO 2 hydrate promoter is less than about 9 atm, usually less than about 5 atm and may be as low as 2 atm or 1 atm or lower.
  • the specific amount of gaseous CO2 hydrate promoter that is present in the provided multicomponent gaseous stream of this first step depends, in large part, on the nature of the multicomponent gaseous stream, the nature of the CO 2 hydrate promoter, and the like, where representative amounts for different types of represenative multicomponent gaseous streams are provided infra.
  • the amount of CO 2 hydrate promoter that is present, initially, in the multicomponent gaseous stream ranges from about 1 to 5 mole percent, usually from about 1.5 to 4 mole percent and more usually from about 2 to 3 mole percent.
  • the specific amount of liquid CO 2 hydrate promoter, dissolved in the CO 2 nucleated water (hydrate precursor solution) depends, in large part, on the nature of the specific dissolved liquid or solid in the nucleated water stream, the nature of the CO2 hydrate promoters, and the like, where representative amounts for different types of representative dissolved liquid or solid hydrate promoters are provide infra.
  • the amount of dissolved CO 2 promoter that is present in the nucleated water stream ranges from about 10 ppm to 10,000 ppm, usually from about 100 ppm to 2000 ppm and more usually from about 150 ppm to 1500 ppm.
  • CO 2 hydrate promoter Any convenient gaseous CO 2 hydrate promoter that is capable of providing the above described reduction in CO 2 partial pressure requirement of hydrate formation when present in the multicomponent gaseous stream may be employed.
  • suitable CO 2 hydrate promoters are low molecular weight compounds that have low vapor pressures at their hydrate formation pressure.
  • low vapor pressure is meant a vapor pressure ranging from about 0.1 to 1 atm, usually from about 0.2 to .95 atm and more usually from about 0.25 to 0.92 atm.
  • low molecular weight is meant a molecular weight that does not exceed about 350 daltons, usually does not exceed about 100 daltons and more usually does not exceed about 75 daltons.
  • gaseous CO 2 hydrate promoter is a sulfur containing compound, where specific sulfur containing compounds of interest include: H 2 S, SO 2 , CS 2 and the like.
  • H S it is generally present in the multicomponent gaseous stream in an amount ranging from about 1.0 to 5.0 mole percent, usually from about 1.5 to 4.0 mole percent and more usually from about 2.0 to 3.0 mole percent.
  • SO 2 it is generally present in the multicomponent gaseous stream in an amount ranging from about 1.0 to 5.0 mole percent, usually from about 1.5 to 4.0 mole percent and more usually from about 2.0 to 3.0 mole percent.
  • CO 2 hydrate promoters are proton donors, such as water soluble halogenated hydrocarbons, amines and the like.
  • Water soluble halogenated hydrocarbons of interest are generally those having from 1 to 5, usually 1 to 4 and more usually 1 to 2 carbon atoms, where the halogen moiety may be F, Cl, Br, I etc.
  • Specific halogenated hydrocarbons of interest include chloroform, ethylene chloride, carbon tetrachloride, and the like.
  • the CO 2 hydrate promoter is ethylene chloride, it is generally dissolved in the nucleated water in an amount ranging from about 100 to 2500 ppm, usually from about 500 to 2000 ppm and more usually from about 1000 to 1800 ppm.
  • CO 2 hydrate promoter is chloroform
  • it is generally present in the nucleated water in an amount ranging from about 100 to 2500 ppm, usually from about 500 to 2000 ppm and more usually from about 1000 to 1800 ppm.
  • CO 2 hydrate promoter is carbon tetrachloride
  • it is generally present in the nucleated water in an amount ranging from about 50 to 200 ppm, usually from about 80 to 160 ppm and more usually from about 100 to 120 ppm.
  • amines such as diethanolamine
  • diethanolamine it is generally present in the nucleated water stream in an amount ranging from about 1000 to 5000 ppm, usually from about 500 to 3000 ppm and more usually from about 1000 to 3000 ppm.
  • alkyl ammonium salts are compounds with cations of the generic formula:
  • R may be methyl or normal (linear) C4H , but may also be iso-C 3 H ⁇ . Of the four groups attached to the nitrogen, they need not all be of the same chemical composition (i.e. one may be methyl while another may be ethyl etc.).
  • the anionic portion of the salt may consist of simple ions such as: F-, HCOO-, OH-, Br-, C1-, NO 3 -, etc, but may also be ions such as normal (linear): nCaH 2a + ⁇ COO- or iso-nCaH 2 a +1 COO-.
  • the sulfonium salts usually are compounds with cations of the generic formula:
  • R 3 S+ where again R may be any of the possibilities cited above.
  • R may be any of the possibilities cited above.
  • all three R's need not be of the same chemical composition.
  • the anion for the sulfonium salts is usually F-.
  • the phosphonium salts generally have the generic formula: R A P+ for the cations with the same choices for the four R groups as described above.
  • the anions may be anions as described above.
  • This class of akyl-onium salts readily form hydrate structures involving encagement of the salt in the same class of polyhedral water cages as seen in the simple gas hydrates. (In many cases the anion actually is part of the cage structure.)
  • the hydrates of these salts form at atmospheric pressure and are stable well above the freezing point of water (where some melting points exceed 20 °C).
  • the above described "onium" salts vary widely in the number of water molecules per salt molecule (i.e. the hydration number).
  • the hydration number may be as low as 4 (for hydroxide salts) and as high as 50 (for formate salts), but will typically range from about 18 to 38 (e.g. for flouride and oxalate salts).
  • concentration to be used depends on which embodiment of the invention is employed. When used as a means for nucleating water, concentrations are similar to the gaseous promoters, usually in the range of 100 to 150 ppm. However, when used to form mixed hydrates, the promoter salt concentration may be substantially higher depending on the final partial pressure of CO2 that is sought. For the "onium" salts, this could be as high as 30 wt. percent, but is more typically in the range of from 5 to 25% by wt.
  • the promoter structure away from the charged end is chosen to be chemically similar to the gaseous component whose solubility is to be decreased and chosen to have an affinity for gas molecules whose solubility is to be increased. Since alteration of gaseous solubility would typically be used in conjunction with the other embodiments (e.g. formation of mixed hydrates, raising of T, or lowering of P) the concentrations could be as high as 30 wt. %, but typically would be about 5 to 25 wt. %.
  • the above organic or onium salts find particular use as hydrate promoters in the following applications: (1) as a means of nucleating water so that CO2 hydrates from for readily; (2) as a means of forming mixed hydrates of CO2 and the alkyl-onium salts, where the mixed hydrates may consist predominantly of salt guest molecules and are useful in the final step to bring the CO2 partial pressure down to below 1 atm; (3) as a means of raising the temperature at which CO2 hydrates or mixed CO2-alkyl-onium salt hydrates will form; (4) as a means to lower the partial pressure of CO 2 required for formation of the CO 2 containing hydrates; (b) as a means to alter the solubility of gases in the process water.
  • the R-groups on the cations are typically chosen so as to lower the solubility of compounds where incorporation into the CO 2 or mixed hydrate is undesirable.
  • R's may be chosen as hydrocarbon moieties which lower the solubility of methane in water for natural gas upgrading gas applications.
  • the R groups are chosen so that solubility of gases, whose incorporation into the hydrate is desirable, is increased.
  • An example would be R groups with a mild chemical affinity for the solvated gas of interest, e.g. CO 2 .
  • the nucleated water further includes a freezing point depression agent or "anti-freeze" agent.
  • Frezing point depression agents that may be included in the nucleated water are glycerol, ethylene glycol, and the like.
  • the amount of freezing point depressing agent that is included is generally sufficient to reduce the freezing point of the nucleated water by at least about 5, usually by at least about 10 and up to 20 °C or more. As such, the amount of freezing point depressing agent in the nucleated water typically ranges from about 20 to 30% by volume.
  • the multicomponent gaseous stream may be provided in the first step of the subject invention using any convenient protocol.
  • a multicomponent gaseous stream of interest will merely be tested to ensure that it includes the requisite amount of CO 2 hydrate promoter of interest.
  • this step requires adding a sufficient amount of the CO 2 hydrate promoter to the multicomponent gaseous stream to be treated.
  • the requisite amount of CO2 hydrate promoter that needs to be added to a given multicomponent gaseous stream of interest necessarily varies depending on the nature of the gaseous stream, the nature of the CO2 hydrate promoter, the desired CO 2 separation ratio and the like.
  • the requisite amount of CO 2 hydrate promoter may be added to the multicomponent gaseous stream using any convenient protocol, e.g. by combining gaseous streams, recycling gaseous compounds, adding appropriate gaseous components, etc.
  • the next step in the subject methods is to contact the multicomponent gaseous stream with an aqueous fluid under conditions sufficient for CO2 hydrate formation to occur.
  • aqueous fluids of interest include water, either pure water or salt water, CO 2 nucleated water as described in U.S. Patent No. 5,700,311 and U.S. Patent Application Serial Nos. 09/067,937 and 09/330,251 ; the disclosures of which are herein incorporated by reference, and the like.
  • the aqueous fluid may include a CO2 hydrate promoter in certain embodiments.
  • Aqueous fluids such as nucleated water containing a CO2 hydrate promoter may be prepared using any convenient protocol, e.g. by introducing an appropriate amount of the liquid CO2 hydrate promoter to the aqueous fluid.
  • the multicomponent gaseous stream to be treated according to the subject methods is contacted with water which may contain CO2 hydrate precursors or hydrate precursors of the promoter compounds.
  • the nucleated water may or may not include a CO 2 hydrate promoter, as described above.
  • the CO2 nucleated water employed in these embodiments of the subject invention comprises dissolved CO2 in the form of CO 2 hydrate precursors, where the precursors are in metastable form.
  • the mole fraction of CO 2 in the CO2 nucleated water ranges from about 0.01 to 0.10, usually from about 0.02 to 0.08, more usually from about 0.04 to 0.06.
  • the temperature of the CO 2 nucleated water typically ranges from about -1.5 to 10 °C, preferably from about 0 to 5°C, and more preferably from about 0.5 to 3.0 °C. In those embodiments in which an antifreeze is employed, the temperature often ranges from about -20 to -5 °C.
  • CO 2 nucleated water employed in the subject methods as the selective liquid absorbent or adsorbent may be prepared using any convenient means.
  • One convenient means of obtaining CO 2 nucleated water is described in U.S. Application Serial No. 08/291,593, filed August 16, 1994, now U.S. Pat. No. 5,562,891, the disclosure of which is herein incorporated by reference.
  • CO 2 is first dissolved in water using any convenient means, e.g. bubbling a stream of CO2 gas through the water, injection of CO 2 into the water under conditions of sufficient mixing or agitation to provide for homogeneous dispersion of the CO2 throughout the water, and the like, where the CO2 source that is combined with the water in this first stage may be either in liquid or gaseous phase.
  • gaseous CO2 is combined with water to make the CO2 nucleated water
  • the gaseous CO2 will typically be pressurized, usually to partial pressures ranging between 6 to 50 atm, more usually between about 10 to 20 atm.
  • the CO 2 may be derived from any convenient source.
  • at least a portion of the CO 2 is gaseous CO 2 obtained from a CO 2 hydrate slurry decomposition step, as described in greater detail below.
  • the water in which the CO 2 is dissolved may be fresh water or salt water, e.g. sea water, or may contain CO2 hydrate promoters.
  • the temperature of the CO 2 nucleated water typically ranges from about -1.5 to 10°C, preferably from about 0 to 5°C, and more preferably from about 0.5 to 3.0 °C. In those embodiments in which an antifreeze is employed, the temperature often ranges from about -20 to -5 °C.
  • the water that is used to produce the nucleated water may be obtained from any convenient source, where convenient sources include the deep ocean, deep fresh water aquifers, powerplant cooling ponds, and the like, and cooled to the required reactor conditions.
  • the nucleated water may be recycled from a downstream source, such a clathrate slurry heat exchanger/decomposition source (as described in greater detail below) where such recycled nucleated water may be supplemented as necessary with additional water, which water may or may not be newly synthesized nucleated water as described above and may, or may not, contain dissolved CO2 hydrate promoters.
  • the amount of CO 2 which is dissolved in the water is determined in view of the desired CO 2 mole fraction of the CO 2 nucleated water to be contacted with the gaseous stream.
  • One means of obtaining CO 2 nucleated water having relatively high mole fractions of CO2 is to produce a slurry of CO 2 clathrates and then decompose the clathrates by lowering the pressure and/or raising the temperature of the slurry to release CO 2 and regenerate a partially nucleated water stream.
  • nucleated water having higher mole fractions of CO2 are desired because it more readily accepts CO2 absorption or adsorption and limits formation of other hydrate compounds.
  • high mole fraction of CO 2 is meant a mole fraction of about 0.05 to 0.09, usually from about 0.06 to 0.08
  • the production of CO2 nucleated water may conveniently be carried out in a nucleation reactor.
  • the reactor may be packed with a variety of materials, where particular materials of interest are those which promote the formation of CO2 nucleated water with hydrate precursors and include: stainless steel rings, carbon steel rings, metal oxides and the like, to promote gas-liquid contact and catalyze hydrate formation.
  • active coolant means may be employed. Any convenient coolant means may be used, where the coolant means will typically comprise a coolant medium housed in a container which contacts the reactor, preferably with a large surface area of contact, such as coils around and/or within the reactor or at least a portion thereof, such as the tail tube of the reactor.
  • Coolant materials or media of interest include liquid ammonia, HCFCs, and the like, where a particular coolant material of interest is ammonia, where the ammonia is evaporated at a temperature of from about -10 to -5 ° C.
  • the surface of the cooling coils, or a portion thereof, may be coated with a catalyst material, such as an oxide of aluminum, iron, chromium, titanium, and the like, to accelerate CO 2 hydrate precursor formation. Additionally, hydrate crystal seeding or a small (1-3 atm) pressure swing may be utilized to enhance hydrate precursor formation.
  • the CO2 nucleated water is prepared by contacting water (e.g. fresh or salt water) with high pressure, substantially pure CO 2 gas provided from an external high pressure CO 2 gas source.
  • water e.g. fresh or salt water
  • substantially pure CO 2 gas provided from an external high pressure CO 2 gas source.
  • the water is contacted with substantially pure CO 2 gas which is at a pressure that is about equal to or slightly above the total multicomponent gaseous stream pressure.
  • the pressure of the substantially pure CO 2 gas typically ranges in many embodiments from about 5 to 7 atm above the multicomponent gaseous stream pressure, and may be 15 to 80, usually 20 to 70 and more usually 25 to 60 atm above the CO2 partial pressure of the multicomponent gaseous stream (CO2 overpressure stimulation of hydrate precursor and hydrate formation).
  • substantially pure is meant that the CO 2 gas is at least 95% pure, usually at least 99% pure and more usually at least 99.9% pure.
  • Advantages realized in this preferred embodiment include the production of CO2 saturated water that comprises high amounts of dissolved CO2, e.g. amounts (mole fractions) ranging from about 0.02 to 0.10, usually from about 0.04 to 0.08. Additional advantages include the use of relatively smaller nucleation reactors (as compared to nucleation reactors employed in other embodiments of the subject invention) and the production of more CO 2 selective nucleated water. In those embodiments where small nucleation reactors are employed, it may be desirable to batch produce the CO 2 saturated water, e.g.
  • the multicomponent gaseous stream with or without hydrate promoters is contacted with the aqueous fluid, e.g.
  • the aqueous fluid may be contacted with the gaseous stream using any convenient means.
  • Preferred means of contacting the aqueous fluid with the gaseous stream are those means that provide for efficient removal, e.g. by absorption or adsorption which enhances hydrate formation, of the CO 2 from the gas through solvation of the gaseous CO 2 within the liquid phase.
  • Means that may be employed include concurrent contacting means, i.e. contact between unidirectionally flowing gaseous and liquid phase streams, countercurrent means, i.e. contact between oppositely flowing gaseous and liquid phase streams, and the like.
  • contact may be accomplished through use of fluidic Venturi reactor, spray, tray, or packed column reactors, and the like, as may be convenient.
  • contact between the multicomponent gaseous stream and the aqueous fluid is carried out in a hydrate or clathrate formation reactor.
  • the reactor may be fabricated from a variety of materials, where particular materials of interest are those which catalyze the formation of CO 2 clathrates or hydrates and include: stainless steel, carbon steel, and the like.
  • the reactor surface, or a portion thereof, may be coated with a catalyst material, such as an oxide of aluminum, iron, chromium, titanium, and the like, to accelerate CO 2 hydrate formation.
  • active coolant means may be employed.
  • coolant means may be used, where the coolant means will typically comprise a coolant medium housed in a container which contacts the reactor, preferably with a large surface area of contact, such as coils around or within the reactor or at least a portion thereof, such as the exit plenum and tail tube of the reactor.
  • Coolant materials or media of interest include ammonia, HCFCs and the like, where a particular coolant material of interest is ammonia, where the ammonia is maintained at a temperature of from about -10 to -5 ° C.
  • the reactor comprises gas injectors as the means for achieving contact to produce clathrates, the reactor may comprise 1 or a plurality of such injectors.
  • the number of injectors will range from 1 to about 20 or more, where multiple injectors provide for greater throughput and thus greater clathrate production.
  • Specific examples of various reactors that may be employed for clathrate production are provided in U.S. Application Serial No. 09/067,937, the disclosure of which is herein incorporated by reference.
  • the clathrate formation conditions under which the gaseous and liquid phase streams are contacted may vary but will preferably be selected so as to provide for the selective formation of CO 2 clathrates, limiting the clathrate formation of other components of the multi-component gaseous stream.
  • the temperature at which the gaseous and liquid phases are contacted will range from about -1.5 to 10 °C, usually from about -0 to 5°C, more usually from about 0.5 to 3.0° C.
  • the total pressure of the environment in which contact occurs, e.g. in the reactor in which contact occurs may range from about 3 to 200 atm, usually from about 10 to 100 atm.
  • the CO 2 partial pressure at which contact occurs generally does not exceed about 80 atm, and usually does not exceed bout 40 atm.
  • the minimum CO 2 partial pressure at which hydrates form in the presence of CO 2 hydrate promoters is generally less than about 9 atm, usually less than about 5 atm and may be as low or 2 or 1 atm or lower.
  • the CO 2 concentration is reduced by at least about 50 %, usually by at least about 70 %, and more usually by at least about 90 %, as compared to the untreated multicomponent gaseous stream.
  • contact of the multicomponent gaseous stream with the CO 2 nucleated water results in at least a decrease in the concentration of the CO 2 of the gaseous phase, where the decrease will be at least about 50 %, usually at least about 70 %, more usually at least about 90 %.
  • the concentration of CO 2 in the gaseous phase may be reduced to the level where it does not exceed 5 % (v/v), such that the treated gaseous stream is effectively free of CO 2 solute gas.
  • many embodiments of the subject methods provide for a "single-pass" efficiency of CO 2 removal of at least about 50%, and often at least about 75 or 90% or higher.
  • the CO2 removed from the multicomponent gaseous stream is concomitantly fixed in the form of stable CO 2 clathrates.
  • Fixation of the CO 2 in the form of stable CO 2 clathrates results in the conversion of the aqueous fluid to a slurry of CO 2 clathrates.
  • the slurry of CO 2 clathrates produced upon contact of the gaseous stream with the aqueous fluid comprises CO2 stably fixed in the form of CO2 clathrates and water.
  • Typical mole fractions of CO 2 in stable clathrates are 0.12 to 0.15.
  • the CO 2 mole fraction may be lower, in the range of 0.05 to 0.12. These lower mole fractions may be employed, particularly if a two (2) stage hydrate reactor process is utilized., wherein the concentration of hydrate promoters may be varied between the two (2) stages to enhance low CO 2 partial pressure hydrate formation, particularly in the second stage. In these cases mixed hydrates of CO 2 and the promoter liquid or salt will form and permit lower CO 2 partial pressures, as low as 1 atm or less, to form hydrates; thus increasing overall CO 2 separation ratios from the multicomponent gaseous stream.
  • Methods of the subject invention generally also include the separation of the treated gaseous phase from the CO 2 clathrate slurry.
  • the gaseous phase may be separated from the slurry in the reactor or in a downstream gas-liquid separator. Any convenient gas-liquid phase separation means may be employed, where a number of such means are known in the art.
  • the gas-liquid separator that is employed is a horizontal separator with one or more, usually a plurality of, gas offtakes on the top of the separator.
  • the subject invention provides for extremely high recovery rates of the multicomponent gaseous stream. In other words, the amount of non-CO 2 gases removed from the multicomponent gaseous stream following selective CO 2 extraction according to the subject invention are extremely low.
  • the amount of combustible gases (i.e. H 2 , CEL and CO) recovered is above 99%, usually above 99.2 % and more usually above 99.5%, where the amount recovered ranges in many embodiments from about 99.6 to 99.8%.
  • the resultant CO 2 clathrate slurry may be disposed of directly as is known in the art, e.g. through placement in gas wells, the deep ocean or freshwater aquifers, and the like, or subsequently processed to separate the clathrates from the remaining nucleated water, where the isolated clathrates may then be disposed of according to methods known in the art and the remaining nucleated water recycled for further use as a selective CO 2 absorbent in the subject methods, and the like.
  • CO 2 gas can easily be regenerated from the clathrates, e.g. where high pressure CO 2 is to be a product or further processed for sequestration, using known methods.
  • the resultant CO 2 gas may be disposed of by transport to the deep ocean or ground aquifers, or used in a variety of processes, e.g. enhanced oil recovery, coal bed methane recovery, or further processed to form metal carbonates, e.g. MgCO 3 , for fixation and sequestration.
  • the CO2 hydrate slurry is treated in a manner sufficient to decompose the hydrate slurry into CO2 gas and CO2 nucleated water, i.e. it is subjected to a decomposition step.
  • the CO 2 hydrate slurry is thermally treated, e.g. flashed, where by thermally treated is meant that temperature of the CO 2 hydrate slurry is raised in sufficient magnitude to decompose the hydrates and produce CO2 gas.
  • the temperature of the CO 2 hydrate slurry is raised to a temperature of between about 40 to 50 °F, at a pressure ranging from about 3-20 to 200 atm, usually from about 40 to 100 atm.
  • One convenient means of thermally treating the CO 2 hydrate slurry is in a counterflow heat exchanger, where the heat exchanger comprises a heating medium in a containment means that provides for optimal surface area contact with the clathrate slurry.
  • any convenient heating medium may be employed, where specific heating media of interest include: ammonia, HCFC's and the like, with ammonia vapor at a temperature ranging from 20 to 40 °C being of particular interest.
  • the ammonia vapor is that vapor produced in cooling the nucleation and/or hydrate formation reactors, as described in greater detail in terms of the figures.
  • Multicomponent gaseous streams that may be treated according to the subject invention will comprise at least two different gaseous components and may comprise five or more different gaseous components, where at least one of the gaseous components will be CO 2 , where the other component or components may be one or more of N , O 2 , H 2 O, CBU, H2, CO and the like, as well as one or more trace gases, e.g. H 2 S, SO 2 , etc.
  • the total pressure of the gas will generally be at least about 15 atm, usually at least about 20 atm and more usually at least about 40 atm.
  • the mole fraction of CO2 in the multicomponent gaseous streams amenable to treatment according to the subject invention will typically range from about 0.10 to 0.90, usually from about 0.15 to 0.70, more usually from about 0.30 to 0.60 atm.
  • the partial pressure of CO 2 in the multicomponent gaseous stream need not be high, and may be as low as 5 atm or lower, e.g. 2 or 1 atm or lower.
  • Multicomponent gaseous streams that may be treated according to the subject methods include both reducing, e.g. syngas, shifted syngas, natural gas, and hydrogen and the like, and oxidizing condition streams, e.g. flue gases from combustion.
  • Particular multicomponent gaseous streams of interest that may be treated according to the subject invention include: oxygen containing combustion power plant flue gas, turbo charged boiler product gas, coal gasification product gas, shifted coal gasification product gas, anaerobic digester product gas, wellhead natural gas stream, reformed natural gas or methane hydrates, and the like.
  • Multicomponent gaseous mediums in which the partial pressures of each of the components are suitable for selective CO2 hydrate formation according to the subject invention may be treated directly without any pretreatment or processing.
  • multicomponent gaseous mediums that are not readily suitable for treatment by the subject invention e.g. in which the partial pressure of CO 2 is too low and/or the partial pressure of the other components are too high, may be subjected to a pretreatment or preprocessing step in order to modulate the characteristics of the gaseous medium so that is suitable for treatment by the subject method.
  • Illustrative pretreatment or preprocessing steps include: temperature modulation, e.g. heating or cooling, decompression, compression, incorporation of additional components, e.g. H2S and other hydrate promoter gases, and the like.
  • the subject methods and systems provide for a number of advantages.
  • the subject methods provide for extremely high CO 2 removal rates and separation ratios from the multicomponent gaseous stream.
  • the CO 2 separation ratio exceeds about 75%.
  • the CO 2 removal rate may exceed about 90% or even 95%in many embodiments.

Abstract

Methods are provided for the selective removal of CO2 from a multicomponent gaseous stream to provide a CO2 depleted gaseous stream having at least a reduction, e.g. 30 to 90 %, in the concentration of CO2 relative to the untreated multicomponent gaseous stream. In practicing the subject methods, the multicomponent gaseous stream is contacted with an aqueous fluid, e.g. CO2 nucleated water, under conditions of selective CO2 clathrate formation to produce a CO2 clathrate slurry and CO2 depleted gaseous stream. A feature of the subject invention is that a CO2 hydrate promoter is employed, where the CO2 hydrate promoter is included in the multicomponent gaseous stream and/or the aqueous fluid. The CO2 hydrate promoter serves to desirably modulate the thermodynamic conditions of hydrate formation, e.g., by reducing the minimum CO2 partial pressure required for formation of CO2 containing hydrates (i.e. CO2 hydrates) and/or increasing the temperature at which hydrate formation occurs, as compared to a control using pure CO2 gas and water. In certain embodiments, the promoter also serves to increase the kinetics of hydrate formation. The subject methods find use in a variety of applicants where it is desired to selectively remove CO2 from a multicomponent gaseous stream.

Description

METHODS OF SELECTIVELY SEPARATING CO2
FROM A MULTICOMPONENT GASEOUS STREAM
USING CO2 HYDRATE PROMOTERS
INTRODUCTION
Field of the Invention
The field of this invention is selective absorption of CO2 gas. Introduction
In many applications where mixtures of two or more gaseous components are present, it is often desirable to selectively remove one or more of the component gases from the gaseous stream. Of increasing interest in a variety of industrial applications, including power generation, chemical synthesis, natural gas upgrading, and conversion of methane hydrates to hydrogen and CO , is the selective removal of CO2 from multicomponent gaseous streams. An example of where selective CO2 removal from a multicomponent gaseous stream is desirable is the processing of synthesis gas or syngas. Syngas is a mixture of hydrogen, carbon monoxide and CO2 that is readily produced from fossil fuels and finds use both as a fuel and as a chemical feedstock. In many applications involving syngas, the carbon monoxide is converted to hydrogen and additional CO2 via the water-gas shift process. It is then often desirable to separate the CO2 from the hydrogen to obtain a pure H2 stream for subsequent use, e.g. as a fuel or feedstock.
As man made CO2 is increasingly viewed as a pollutant, another area in which it is desirable to separate CO2 from a multicomponent gaseous stream is in the area of pollution control. Emissions from industrial facilities, such as manufacturing and power generation facilities, often include CO2. In such instances, it is often desirable to at least reduce the CO2 concentration of the emissions. The CO2 may be removed prior to combustion in some cases and post combustion in others.
A variety of processes have been developed for removing or isolating a particular gaseous component from a multicomponent gaseous stream. These processes include cryogenic fractionation, selective adsorption by solid adsorbents, gas absorption, and the like. In gas absorption processes, solute gases are separated from gaseous mixtures by transport into a liquid solvent. In such processes, the liquid solvent ideally offers specific or selective solubility for the solute gas or gases to be separated.
Gas absorption finds widespread use in the separation of CO2 from multicomponent gaseous streams. In CO2 gas absorption processes that currently find use, the following steps are employed: (1) absorption of CO2 from the gaseous stream by a host solvent, e.g. monoethanolamine; (2) removal of CO2 from the host solvent, e.g. by steam stripping; and
(3) compression of the stripped CO2 for disposal, e.g. by sequestration through deposition in the deep ocean or ground aquifers. Although these processes have proved successful for the selective removal of CO2 from a multicomponent gaseous stream, they are energy intensive. For example, using the above processes employing monoethanolamine as the selective absorbent solvent to remove
CO2 from effluent flue gas generated by a power plant often requires 25 to 30 % of the available energy generated by the plant. In most situations, this energy requirement, as well as the additional cost for removing the CO2 from the flue gas, is prohibitive.
Accordingly, there is continued interest in the development of less energy intensive processes for the selective removal of CO2 from multicomponent gaseous streams. Ideally, alternative CO2 removal processes should be simple, require inexpensive materials and low energy inputs, and be low in cost for separation and sequestration of the CO2. Of particular interest would be the development of a process which provided for efficient CO2 separation at low temperature (e.g. 0 to 10° C) from low CO2 partial pressure multicomponent gaseous streams.
Relevant Literature
Patents disclosing methods of selectively removing one or more components from a multicomponent gaseous stream include: 3,150,942; 3,359,744; 3,479,298; 3,838,553;
4,253,607; 4,861,351; 5,397,553; 5,434,330; 5,562,891; 5,600,044 and 5,700,311.
Other publications discussing CO2 clathrate formation include Japanese unexamined patent application 3-164419; Austvik & Løken, "Deposition of CO2 on the Seabed in the Form of Clathrates, " Energy Convers. Mgmt. (1992) 33: 659-666; Golumb et al, "The Fate of CO2 Sequestered in the Deep Ocean," Energy Convers. Mgmt. (1992) 33: 675-683; Morgan et al., "Hydrate Formation from Gaseous CO2 and water," Environmental Science and Technology (1999) 33: 1448-1452; Nishikawa et al, "CO2 Clathrate Formation and its Properties in the Simulated Deep Ocean," Energy Convers. Mgmt. (1992) 33:651-657; Saji etal, "Fixation of Carbon Dioxide by Clathrate-Hyrdrate," Energy Convers. Mgmt. (1992) 33: 643-649; Spencer, "A Preliminary Assessment of Carbon Dioxide Mitigation Options," Annu. Rev. Energy Environ. (1991) 16: 259-273; Spencer & North, "Ocean Systems for Managing the Global Carbon Cycle," Energy Convers. Mgmt. (1997) 38 Suppl.: 265-272; and Spencer & White, "Sequestration Processes for Treating Multicomponent Gas Streams," Proceedings of 23rd Coal and Fuel Systems Conference, Clearwater, Florida (March 1998).
SUMMARY OF THE INVENTION
Methods are provided for the selective removal of CO2 from a multicomponent gaseous stream to provide a CO2 depleted gaseous stream having at least a reduction, e.g. 20%, in the concentration of CO2 relative to the untreated multicomponent gaseous stream. In practicing the subject methods, the multicomponent gaseous stream is contacted with an aqueous fluid, e.g. CO2 nucleated (or structured) water, under conditions of selective CO2 clathrate formation to produce a CO2 clathrate slurry and CO2 depleted gaseous stream. A feature of the subject invention is that a CO2 hydrate promoter is employed, where the CO2 hydrate promoter is included in the multicomponent gaseous stream and/or the aqueous fluid. The CO2 hydrate promoter serves to desirably modulate the thermodynamic conditions of hydrate formation, e.g., by reducing the minimum CO2 partial pressure required for formation of CO2 containing hydrates (i.e. CO2 hydrates) and/or increasing the temperature at which hydrate formation occurs, as compared to a control using pure CO2 gas and water. In certain embodiments, the promoter also serves to increase the kinetics of hydrate formation. The subject methods find use in a variety of applications where it is desired to selectively remove CO2 from a multicomponent gaseous stream.
DETAILED DESCRIPTION OF THE INVENTION
Methods are provided for the selective removal of CO2 from a multicomponent gaseous stream to provide a CO2 depleted gaseous stream having at least a reduction, e.g. 30 to 90%, in the concentration of CO2 relative to the untreated multicomponent gaseous stream. In practicing the subject methods, the multicomponent gaseous stream is contacted with an aqueous fluid, e.g. CO2 nucleated (or structure) water, under conditions of selective CO2 clathrate formation to produce a CO2 clathrate slurry and CO2 depleted gaseous stream. A feature of the subject invention is that a CO2 hydrate promoter is employed, where the CO2 hydrate promoter is included in the multicomponent gaseous stream and/or the aqueous fluid. The CO2 hydrate promoter serves to desirably modulate the thermodynamic conditions of hydrate formation, e.g., by reducing the minimum CO2 partial pressure required for formation of CO2 containing hydrates (i.e. CO2 hydrates) and/or increasing the temperature at which hydrate formation occurs, as compared to a control using pure CO2 gas and water. In certain embodiments, the promoter also serves to increase the kinetics of hydrate formation. The subject methods find use in a variety of applications where it is desired to selectively remove CO2 from a multicomponent gaseous stream.
Before the subject invention is described further, it is to be understood that the invention is not limited to the particular embodiments of the invention described below, as variations of the particular embodiments may be made and still fall within the scope of the appended claims. It is also to be understood that the terminology employed is for the purpose of describing particular embodiments, and is not intended to be limiting. Instead, the scope of the present invention will be established by the appended claims.
In this specification and the appended claims, the singular forms "a," "an," and "the" include plural reference unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs.
As summarized above, the subject invention provides a method of selectively removing CO2 from multicomponent gaseous stream, where a feature of the subject methods is the use of a CO2 hydrate promoter. As mentioned above, the CO2 hydrate promoter may be present in the multicomponent gaseous stream and/or in CO2 nucleated or non-nucleated water (hydrate precursor solution).
In the subject methods, the first step is to provide a multicomponent gaseous stream that includes a CO2 hydrate promoter and/or an aqueous fluid, e.g. CO2 nucleated or non- nucleated water (water source), that includes a CO2 hydrate promoter. Specifically, a multicomponent gaseous stream and/or CO2 nucleated water source is provided that includes an amount of a CO2 hydrate promoter that is sufficient to desirably modulate the thermodynamic conditions of hydrate formation, e.g., to reduce the CO2 partial pressure requirement of hydrate formation under a given set of conditions, e.g. at or near 0°C, as compared to a control and/or to increase the temperature of hydrate formation.
By CO2 partial pressure requirement of hydrate formation is meant the CO2 partial pressure in the multicomponent gaseous stream that is required for CO2 hydrate formation to occur upon contact with an aqueous fluid under a given set of conditions, such as the ones described in greater detail, infra. The amount of CO2 hydrate promoter that is present in the multicomponent gaseous stream and/or CO2 nucleated water is generally sufficient to provide for a reduction in the CO2 partial pressure requirement of hydrate formation of at least about 20 %, usually at least about 30 % and more usually at least about 60 % as compared to a control (i.e. the CO2 partial pressure requirement of hydrate formation in the absence of the CO2 hydrate promoter under otherwise identical conditions), where in certain embodiments the magnitude of the reduction may be as great as 85, 90 or 95% or more. For example, the CO2 partial pressure requirement at 0°C in the presence of a sufficient amount of CO2 hydrate promoter is less than about 9 atm, usually less than about 5 atm and may be as low as 2 atm or 1 atm or lower.
In those embodiments where the hydrate promoter increases the temperature at which hydrate formation occurs, the amount of promoter that is present in sufficient to provide for an at least 2 fold and usually at least 5 fold increase in temperature, such that the presence of the hydrate promoter provides for hydrate formation at temperatures in excess of 5°C, preferably at least 10°C and in certain embodiments at least 15, 20, 25 or even 30 °C.
The specific amount of gaseous CO2 hydrate promoter that is present in the provided multicomponent gaseous stream of this first step depends, in large part, on the nature of the multicomponent gaseous stream, the nature of the CO2 hydrate promoter, and the like, where representative amounts for different types of represenative multicomponent gaseous streams are provided infra. Generally, the amount of CO2 hydrate promoter that is present, initially, in the multicomponent gaseous stream ranges from about 1 to 5 mole percent, usually from about 1.5 to 4 mole percent and more usually from about 2 to 3 mole percent.
The specific amount of liquid CO2 hydrate promoter, dissolved in the CO2 nucleated water (hydrate precursor solution) depends, in large part, on the nature of the specific dissolved liquid or solid in the nucleated water stream, the nature of the CO2 hydrate promoters, and the like, where representative amounts for different types of representative dissolved liquid or solid hydrate promoters are provide infra. Generally, the amount of dissolved CO2 promoter that is present in the nucleated water stream ranges from about 10 ppm to 10,000 ppm, usually from about 100 ppm to 2000 ppm and more usually from about 150 ppm to 1500 ppm.
Any convenient gaseous CO2 hydrate promoter that is capable of providing the above described reduction in CO2 partial pressure requirement of hydrate formation when present in the multicomponent gaseous stream may be employed. Generally, suitable CO2 hydrate promoters are low molecular weight compounds that have low vapor pressures at their hydrate formation pressure. By low vapor pressure is meant a vapor pressure ranging from about 0.1 to 1 atm, usually from about 0.2 to .95 atm and more usually from about 0.25 to 0.92 atm. By low molecular weight is meant a molecular weight that does not exceed about 350 daltons, usually does not exceed about 100 daltons and more usually does not exceed about 75 daltons. One type of gaseous CO2 hydrate promoter is a sulfur containing compound, where specific sulfur containing compounds of interest include: H2S, SO2, CS2 and the like. Where the CO2 hydrate promoter is H S, it is generally present in the multicomponent gaseous stream in an amount ranging from about 1.0 to 5.0 mole percent, usually from about 1.5 to 4.0 mole percent and more usually from about 2.0 to 3.0 mole percent. Where the CO2 hydrate promoter is SO2, it is generally present in the multicomponent gaseous stream in an amount ranging from about 1.0 to 5.0 mole percent, usually from about 1.5 to 4.0 mole percent and more usually from about 2.0 to 3.0 mole percent.
Also of particular interest as CO2 hydrate promoters are proton donors, such as water soluble halogenated hydrocarbons, amines and the like. Water soluble halogenated hydrocarbons of interest are generally those having from 1 to 5, usually 1 to 4 and more usually 1 to 2 carbon atoms, where the halogen moiety may be F, Cl, Br, I etc. Specific halogenated hydrocarbons of interest include chloroform, ethylene chloride, carbon tetrachloride, and the like. Where the CO2 hydrate promoter is ethylene chloride, it is generally dissolved in the nucleated water in an amount ranging from about 100 to 2500 ppm, usually from about 500 to 2000 ppm and more usually from about 1000 to 1800 ppm. Where the CO2 hydrate promoter is chloroform, it is generally present in the nucleated water in an amount ranging from about 100 to 2500 ppm, usually from about 500 to 2000 ppm and more usually from about 1000 to 1800 ppm. Where the CO2 hydrate promoter is carbon tetrachloride, it is generally present in the nucleated water in an amount ranging from about 50 to 200 ppm, usually from about 80 to 160 ppm and more usually from about 100 to 120 ppm. In addition, if amines such as diethanolamine, are utilized as a CO2 hydrate promoter, there is even greater flexibility in determining the ideal amount of amine, since the amine is essentially infinitely soluble in water. However, if diethanolamine is utilized, it is generally present in the nucleated water stream in an amount ranging from about 1000 to 5000 ppm, usually from about 500 to 3000 ppm and more usually from about 1000 to 3000 ppm.
Also of particular interest as CO2 promoters are the ogranic salts, particularly alkyl ammonium, sulfonium and phosphonium salts. The alkyl ammonium salts are compounds with cations of the generic formula:
R4N+ where R usually consists of hydrocarbon elements of the formula: nCaH2a+ι n=l,2,3... a=l,2,3
For example, R may be methyl or normal (linear) C4H , but may also be iso-C3Hπ. Of the four groups attached to the nitrogen, they need not all be of the same chemical composition (i.e. one may be methyl while another may be ethyl etc.). The anionic portion of the salt may consist of simple ions such as: F-, HCOO-, OH-, Br-, C1-, NO3-, etc, but may also be ions such as normal (linear): nCaH2a+ιCOO- or iso-nCaH2a+1 COO-. The sulfonium salts usually are compounds with cations of the generic formula:
R3S+ where again R may be any of the possibilities cited above. Similarly, for the sulfonium salts, all three R's need not be of the same chemical composition. The anion for the sulfonium salts is usually F-. The phosphonium salts generally have the generic formula: RAP+ for the cations with the same choices for the four R groups as described above. The anions may be anions as described above.
This class of akyl-onium salts readily form hydrate structures involving encagement of the salt in the same class of polyhedral water cages as seen in the simple gas hydrates. (In many cases the anion actually is part of the cage structure.) The hydrates of these salts form at atmospheric pressure and are stable well above the freezing point of water (where some melting points exceed 20 °C). The above described "onium" salts vary widely in the number of water molecules per salt molecule (i.e. the hydration number). For example, the hydration number may be as low as 4 (for hydroxide salts) and as high as 50 (for formate salts), but will typically range from about 18 to 38 (e.g. for flouride and oxalate salts). The concentration to be used depends on which embodiment of the invention is employed. When used as a means for nucleating water, concentrations are similar to the gaseous promoters, usually in the range of 100 to 150 ppm. However, when used to form mixed hydrates, the promoter salt concentration may be substantially higher depending on the final partial pressure of CO2 that is sought. For the "onium" salts, this could be as high as 30 wt. percent, but is more typically in the range of from 5 to 25% by wt.
When used to alter the solubility of charged gases, the promoter structure away from the charged end is chosen to be chemically similar to the gaseous component whose solubility is to be decreased and chosen to have an affinity for gas molecules whose solubility is to be increased. Since alteration of gaseous solubility would typically be used in conjunction with the other embodiments (e.g. formation of mixed hydrates, raising of T, or lowering of P) the concentrations could be as high as 30 wt. %, but typically would be about 5 to 25 wt. %.
The above organic or onium salts find particular use as hydrate promoters in the following applications: (1) as a means of nucleating water so that CO2 hydrates from for readily; (2) as a means of forming mixed hydrates of CO2 and the alkyl-onium salts, where the mixed hydrates may consist predominantly of salt guest molecules and are useful in the final step to bring the CO2 partial pressure down to below 1 atm; (3) as a means of raising the temperature at which CO2 hydrates or mixed CO2-alkyl-onium salt hydrates will form; (4) as a means to lower the partial pressure of CO2 required for formation of the CO2 containing hydrates; (b) as a means to alter the solubility of gases in the process water. The R-groups on the cations are typically chosen so as to lower the solubility of compounds where incorporation into the CO2 or mixed hydrate is undesirable. For example, R's may be chosen as hydrocarbon moieties which lower the solubility of methane in water for natural gas upgrading gas applications. In certain embodiments, the R groups are chosen so that solubility of gases, whose incorporation into the hydrate is desirable, is increased. An example would be R groups with a mild chemical affinity for the solvated gas of interest, e.g. CO2. In certain embodiments of the invention, the nucleated water further includes a freezing point depression agent or "anti-freeze" agent. Frezing point depression agents that may be included in the nucleated water are glycerol, ethylene glycol, and the like. The amount of freezing point depressing agent that is included is generally sufficient to reduce the freezing point of the nucleated water by at least about 5, usually by at least about 10 and up to 20 °C or more. As such, the amount of freezing point depressing agent in the nucleated water typically ranges from about 20 to 30% by volume.
The multicomponent gaseous stream may be provided in the first step of the subject invention using any convenient protocol. In certain embodiments, a multicomponent gaseous stream of interest will merely be tested to ensure that it includes the requisite amount of CO2 hydrate promoter of interest. Generally, however, this step requires adding a sufficient amount of the CO2 hydrate promoter to the multicomponent gaseous stream to be treated. The requisite amount of CO2 hydrate promoter that needs to be added to a given multicomponent gaseous stream of interest necessarily varies depending on the nature of the gaseous stream, the nature of the CO2 hydrate promoter, the desired CO2 separation ratio and the like. The requisite amount of CO2 hydrate promoter may be added to the multicomponent gaseous stream using any convenient protocol, e.g. by combining gaseous streams, recycling gaseous compounds, adding appropriate gaseous components, etc.
Following provision of the multicomponent gaseous stream that includes the requisite amount of CO2 hydrate promoter (when desired), the next step in the subject methods is to contact the multicomponent gaseous stream with an aqueous fluid under conditions sufficient for CO2 hydrate formation to occur. Any convenient aqueous fluid may be employed, where aqueous fluids of interest include water, either pure water or salt water, CO2 nucleated water as described in U.S. Patent No. 5,700,311 and U.S. Patent Application Serial Nos. 09/067,937 and 09/330,251 ; the disclosures of which are herein incorporated by reference, and the like. As discussed above, the aqueous fluid may include a CO2 hydrate promoter in certain embodiments. Aqueous fluids such as nucleated water containing a CO2 hydrate promoter may be prepared using any convenient protocol, e.g. by introducing an appropriate amount of the liquid CO2 hydrate promoter to the aqueous fluid. In many embodiments, the multicomponent gaseous stream to be treated according to the subject methods is contacted with water which may contain CO2 hydrate precursors or hydrate precursors of the promoter compounds. The nucleated water may or may not include a CO2 hydrate promoter, as described above. The CO2 nucleated water employed in these embodiments of the subject invention comprises dissolved CO2 in the form of CO2 hydrate precursors, where the precursors are in metastable form. These precursors may be composite for mixed hydrates containing both CO2 and promoter molecules The mole fraction of CO2 in the CO2 nucleated water ranges from about 0.01 to 0.10, usually from about 0.02 to 0.08, more usually from about 0.04 to 0.06. The temperature of the CO2 nucleated water typically ranges from about -1.5 to 10 °C, preferably from about 0 to 5°C, and more preferably from about 0.5 to 3.0 °C. In those embodiments in which an antifreeze is employed, the temperature often ranges from about -20 to -5 °C.
CO2 nucleated water employed in the subject methods as the selective liquid absorbent or adsorbent may be prepared using any convenient means. One convenient means of obtaining CO2 nucleated water is described in U.S. Application Serial No. 08/291,593, filed August 16, 1994, now U.S. Pat. No. 5,562,891, the disclosure of which is herein incorporated by reference. In this method CO2 is first dissolved in water using any convenient means, e.g. bubbling a stream of CO2 gas through the water, injection of CO2 into the water under conditions of sufficient mixing or agitation to provide for homogeneous dispersion of the CO2 throughout the water, and the like, where the CO2 source that is combined with the water in this first stage may be either in liquid or gaseous phase. Where gaseous CO2 is combined with water to make the CO2 nucleated water, the gaseous CO2 will typically be pressurized, usually to partial pressures ranging between 6 to 50 atm, more usually between about 10 to 20 atm. The CO2 may be derived from any convenient source. In a preferred embodiment, at least a portion of the CO2 is gaseous CO2 obtained from a CO2 hydrate slurry decomposition step, as described in greater detail below. The water in which the CO2 is dissolved may be fresh water or salt water, e.g. sea water, or may contain CO2 hydrate promoters. The temperature of the CO2 nucleated water typically ranges from about -1.5 to 10°C, preferably from about 0 to 5°C, and more preferably from about 0.5 to 3.0 °C. In those embodiments in which an antifreeze is employed, the temperature often ranges from about -20 to -5 °C.
The water that is used to produce the nucleated water may be obtained from any convenient source, where convenient sources include the deep ocean, deep fresh water aquifers, powerplant cooling ponds, and the like, and cooled to the required reactor conditions. In certain embodiments, the nucleated water may be recycled from a downstream source, such a clathrate slurry heat exchanger/decomposition source (as described in greater detail below) where such recycled nucleated water may be supplemented as necessary with additional water, which water may or may not be newly synthesized nucleated water as described above and may, or may not, contain dissolved CO2 hydrate promoters.
The amount of CO2 which is dissolved in the water is determined in view of the desired CO2 mole fraction of the CO2 nucleated water to be contacted with the gaseous stream. One means of obtaining CO2 nucleated water having relatively high mole fractions of CO2 is to produce a slurry of CO2 clathrates and then decompose the clathrates by lowering the pressure and/or raising the temperature of the slurry to release CO2 and regenerate a partially nucleated water stream. Generally, nucleated water having higher mole fractions of CO2 are desired because it more readily accepts CO2 absorption or adsorption and limits formation of other hydrate compounds. By high mole fraction of CO2 is meant a mole fraction of about 0.05 to 0.09, usually from about 0.06 to 0.08
The production of CO2 nucleated water may conveniently be carried out in a nucleation reactor. The reactor may be packed with a variety of materials, where particular materials of interest are those which promote the formation of CO2 nucleated water with hydrate precursors and include: stainless steel rings, carbon steel rings, metal oxides and the like, to promote gas-liquid contact and catalyze hydrate formation. To ensure that the optimal temperature is maintained in the nucleation reactor, active coolant means may be employed. Any convenient coolant means may be used, where the coolant means will typically comprise a coolant medium housed in a container which contacts the reactor, preferably with a large surface area of contact, such as coils around and/or within the reactor or at least a portion thereof, such as the tail tube of the reactor. Coolant materials or media of interest include liquid ammonia, HCFCs, and the like, where a particular coolant material of interest is ammonia, where the ammonia is evaporated at a temperature of from about -10 to -5 ° C. The surface of the cooling coils, or a portion thereof, may be coated with a catalyst material, such as an oxide of aluminum, iron, chromium, titanium, and the like, to accelerate CO2 hydrate precursor formation. Additionally, hydrate crystal seeding or a small (1-3 atm) pressure swing may be utilized to enhance hydrate precursor formation.
In a preferred embodiment of the subject invention, the CO2 nucleated water is prepared by contacting water (e.g. fresh or salt water) with high pressure, substantially pure CO2 gas provided from an external high pressure CO2 gas source. In this embodiment, the water is contacted with substantially pure CO2 gas which is at a pressure that is about equal to or slightly above the total multicomponent gaseous stream pressure. As such, the pressure of the substantially pure CO2 gas typically ranges in many embodiments from about 5 to 7 atm above the multicomponent gaseous stream pressure, and may be 15 to 80, usually 20 to 70 and more usually 25 to 60 atm above the CO2 partial pressure of the multicomponent gaseous stream (CO2 overpressure stimulation of hydrate precursor and hydrate formation). By substantially pure is meant that the CO2 gas is at least 95% pure, usually at least 99% pure and more usually at least 99.9% pure. Advantages realized in this preferred embodiment include the production of CO2 saturated water that comprises high amounts of dissolved CO2, e.g. amounts (mole fractions) ranging from about 0.02 to 0.10, usually from about 0.04 to 0.08. Additional advantages include the use of relatively smaller nucleation reactors (as compared to nucleation reactors employed in other embodiments of the subject invention) and the production of more CO2 selective nucleated water. In those embodiments where small nucleation reactors are employed, it may be desirable to batch produce the CO2 saturated water, e.g. by producing the total requisite amount of CO2 saturated water in portions and storing the saturated water in a high pressure reservoir. The CO2 saturated water is readily converted to nucleated water, i.e. water laden with CO2 hydrate precursors, using any convenient means, e.g. by temperature cycling, contact with catalysts, pressure cycling, etc. This prestructuring of the hydrate formation water not only increases the kinetics of hydrate formation, but also reduces the exothermic energy release in the CO2 hydrate reactor. This, in turn, reduces the cooling demands of the process and increases overall process efficiency. As mentioned above, in this step of the subject methods, the multicomponent gaseous stream with or without hydrate promoters is contacted with the aqueous fluid, e.g. CO2 nucleated water with or without hydrate promoters, under conditions of CO2 clathrate formation, preferably under conditions of selective CO2 clathrate formation. The aqueous fluid may be contacted with the gaseous stream using any convenient means. Preferred means of contacting the aqueous fluid with the gaseous stream are those means that provide for efficient removal, e.g. by absorption or adsorption which enhances hydrate formation, of the CO2 from the gas through solvation of the gaseous CO2 within the liquid phase. Means that may be employed include concurrent contacting means, i.e. contact between unidirectionally flowing gaseous and liquid phase streams, countercurrent means, i.e. contact between oppositely flowing gaseous and liquid phase streams, and the like. Thus, contact may be accomplished through use of fluidic Venturi reactor, spray, tray, or packed column reactors, and the like, as may be convenient. Generally, contact between the multicomponent gaseous stream and the aqueous fluid is carried out in a hydrate or clathrate formation reactor. The reactor may be fabricated from a variety of materials, where particular materials of interest are those which catalyze the formation of CO2 clathrates or hydrates and include: stainless steel, carbon steel, and the like. The reactor surface, or a portion thereof, may be coated with a catalyst material, such as an oxide of aluminum, iron, chromium, titanium, and the like, to accelerate CO2 hydrate formation. To ensure that the optimal temperature is maintained in the hydrate formation reactor, active coolant means may be employed. Any convenient coolant means may be used, where the coolant means will typically comprise a coolant medium housed in a container which contacts the reactor, preferably with a large surface area of contact, such as coils around or within the reactor or at least a portion thereof, such as the exit plenum and tail tube of the reactor. Coolant materials or media of interest include ammonia, HCFCs and the like, where a particular coolant material of interest is ammonia, where the ammonia is maintained at a temperature of from about -10 to -5 ° C. Where the reactor comprises gas injectors as the means for achieving contact to produce clathrates, the reactor may comprise 1 or a plurality of such injectors. In such reactors, the number of injectors will range from 1 to about 20 or more, where multiple injectors provide for greater throughput and thus greater clathrate production. Specific examples of various reactors that may be employed for clathrate production are provided in U.S. Application Serial No. 09/067,937, the disclosure of which is herein incorporated by reference.
The clathrate formation conditions under which the gaseous and liquid phase streams are contacted, particularly the temperature and pressure, may vary but will preferably be selected so as to provide for the selective formation of CO2 clathrates, limiting the clathrate formation of other components of the multi-component gaseous stream. Generally, the temperature at which the gaseous and liquid phases are contacted will range from about -1.5 to 10 °C, usually from about -0 to 5°C, more usually from about 0.5 to 3.0° C. The total pressure of the environment in which contact occurs, e.g. in the reactor in which contact occurs, may range from about 3 to 200 atm, usually from about 10 to 100 atm. The CO2 partial pressure at which contact occurs generally does not exceed about 80 atm, and usually does not exceed bout 40 atm. The minimum CO2 partial pressure at which hydrates form in the presence of CO2 hydrate promoters is generally less than about 9 atm, usually less than about 5 atm and may be as low or 2 or 1 atm or lower. Upon contact of the gaseous stream with the aqueous fluid, CO2 is selectively removed from the gaseous stream and CO2 hydrates are formed as the CO2 reacts with the CO2 nucleated water liquid phase containing CO2 hydrate precursors, with or without CO2 hydrate promoters. The removed CO2 is concomitantly fixed as solid CO2 clathrates in the liquid phase slurry. Contact between the gaseous and liquid phases results in the production of a CO2 depleted multicomponent gaseous stream and a slurry of CO2 clathrates. In the CO2 depleted multicomponent gaseous stream, the CO2 concentration is reduced by at least about 50 %, usually by at least about 70 %, and more usually by at least about 90 %, as compared to the untreated multicomponent gaseous stream. In other words, contact of the multicomponent gaseous stream with the CO2 nucleated water results in at least a decrease in the concentration of the CO2 of the gaseous phase, where the decrease will be at least about 50 %, usually at least about 70 %, more usually at least about 90 %. In some instances the concentration of CO2 in the gaseous phase may be reduced to the level where it does not exceed 5 % (v/v), such that the treated gaseous stream is effectively free of CO2 solute gas. As such, many embodiments of the subject methods provide for a "single-pass" efficiency of CO2 removal of at least about 50%, and often at least about 75 or 90% or higher.
As discussed above, the CO2 removed from the multicomponent gaseous stream is concomitantly fixed in the form of stable CO2 clathrates. Fixation of the CO2 in the form of stable CO2 clathrates results in the conversion of the aqueous fluid to a slurry of CO2 clathrates. The slurry of CO2 clathrates produced upon contact of the gaseous stream with the aqueous fluid comprises CO2 stably fixed in the form of CO2 clathrates and water. Typical mole fractions of CO2 in stable clathrates are 0.12 to 0.15.
In cases where CO2 hydrate liquid promoters are employed, either dissolved organic liquids or salts, as discussed previously, the CO2 mole fraction may be lower, in the range of 0.05 to 0.12. These lower mole fractions may be employed, particularly if a two (2) stage hydrate reactor process is utilized., wherein the concentration of hydrate promoters may be varied between the two (2) stages to enhance low CO2 partial pressure hydrate formation, particularly in the second stage. In these cases mixed hydrates of CO2 and the promoter liquid or salt will form and permit lower CO2 partial pressures, as low as 1 atm or less, to form hydrates; thus increasing overall CO2 separation ratios from the multicomponent gaseous stream.
Methods of the subject invention generally also include the separation of the treated gaseous phase from the CO2 clathrate slurry. As convenient, the gaseous phase may be separated from the slurry in the reactor or in a downstream gas-liquid separator. Any convenient gas-liquid phase separation means may be employed, where a number of such means are known in the art. In many preferred embodiments, the gas-liquid separator that is employed is a horizontal separator with one or more, usually a plurality of, gas offtakes on the top of the separator. The subject invention provides for extremely high recovery rates of the multicomponent gaseous stream. In other words, the amount of non-CO2 gases removed from the multicomponent gaseous stream following selective CO2 extraction according to the subject invention are extremely low. For example, where the multicomponent gaseous stream is a shifted synthesis gas stream, the amount of combustible gases (i.e. H2, CEL and CO) recovered is above 99%, usually above 99.2 % and more usually above 99.5%, where the amount recovered ranges in many embodiments from about 99.6 to 99.8%.
Where it is desired to sequester the CO2 clathrates produced by the subject method, the resultant CO2 clathrate slurry may be disposed of directly as is known in the art, e.g. through placement in gas wells, the deep ocean or freshwater aquifers, and the like, or subsequently processed to separate the clathrates from the remaining nucleated water, where the isolated clathrates may then be disposed of according to methods known in the art and the remaining nucleated water recycled for further use as a selective CO2 absorbent in the subject methods, and the like.
Where desired, CO2 gas can easily be regenerated from the clathrates, e.g. where high pressure CO2 is to be a product or further processed for sequestration, using known methods. The resultant CO2 gas may be disposed of by transport to the deep ocean or ground aquifers, or used in a variety of processes, e.g. enhanced oil recovery, coal bed methane recovery, or further processed to form metal carbonates, e.g. MgCO3, for fixation and sequestration. In certain embodiments, the CO2 hydrate slurry is treated in a manner sufficient to decompose the hydrate slurry into CO2 gas and CO2 nucleated water, i.e. it is subjected to a decomposition step. Typically, the CO2 hydrate slurry is thermally treated, e.g. flashed, where by thermally treated is meant that temperature of the CO2 hydrate slurry is raised in sufficient magnitude to decompose the hydrates and produce CO2 gas. Typically, the temperature of the CO2 hydrate slurry is raised to a temperature of between about 40 to 50 °F, at a pressure ranging from about 3-20 to 200 atm, usually from about 40 to 100 atm. One convenient means of thermally treating the CO2 hydrate slurry is in a counterflow heat exchanger, where the heat exchanger comprises a heating medium in a containment means that provides for optimal surface area contact with the clathrate slurry. Any convenient heating medium may be employed, where specific heating media of interest include: ammonia, HCFC's and the like, with ammonia vapor at a temperature ranging from 20 to 40 °C being of particular interest. Preferably, the ammonia vapor is that vapor produced in cooling the nucleation and/or hydrate formation reactors, as described in greater detail in terms of the figures.
A variety of multicomponent gaseous streams are amenable to treatment according to the subject methods. Multicomponent gaseous streams that may be treated according to the subject invention will comprise at least two different gaseous components and may comprise five or more different gaseous components, where at least one of the gaseous components will be CO2, where the other component or components may be one or more of N , O2, H2O, CBU, H2, CO and the like, as well as one or more trace gases, e.g. H2S, SO2, etc. The total pressure of the gas will generally be at least about 15 atm, usually at least about 20 atm and more usually at least about 40 atm. The mole fraction of CO2 in the multicomponent gaseous streams amenable to treatment according to the subject invention will typically range from about 0.10 to 0.90, usually from about 0.15 to 0.70, more usually from about 0.30 to 0.60 atm. The partial pressure of CO2 in the multicomponent gaseous stream need not be high, and may be as low as 5 atm or lower, e.g. 2 or 1 atm or lower. By controlling the clathrate formation conditions, the CO2 hydrate formation precursors and promoters, nucleated water properties, and providing intimate contact between the CO2 nucleated water and the multicomponent gas, the CO2 separation can be controlled to provide for the selective formation of CO2 clathrates, e.g. through use of highly nucleated water containing hydrate precursors and promoters, and perhaps dissolved or dispersed catalysts, which further aids the selective CO2 hydrate formation from the multicomponent gaseous stream and increases CO2 separation efficiency. The particular conditions which provide for the best selectivity with a particular gas can be determined empirically by those of skill in the art. Multicomponent gaseous streams (containing CO2) that may be treated according to the subject methods include both reducing, e.g. syngas, shifted syngas, natural gas, and hydrogen and the like, and oxidizing condition streams, e.g. flue gases from combustion. Particular multicomponent gaseous streams of interest that may be treated according to the subject invention include: oxygen containing combustion power plant flue gas, turbo charged boiler product gas, coal gasification product gas, shifted coal gasification product gas, anaerobic digester product gas, wellhead natural gas stream, reformed natural gas or methane hydrates, and the like.
Multicomponent gaseous mediums in which the partial pressures of each of the components are suitable for selective CO2 hydrate formation according to the subject invention may be treated directly without any pretreatment or processing. For those multicomponent gaseous mediums that are not readily suitable for treatment by the subject invention, e.g. in which the partial pressure of CO2 is too low and/or the partial pressure of the other components are too high, may be subjected to a pretreatment or preprocessing step in order to modulate the characteristics of the gaseous medium so that is suitable for treatment by the subject method. Illustrative pretreatment or preprocessing steps include: temperature modulation, e.g. heating or cooling, decompression, compression, incorporation of additional components, e.g. H2S and other hydrate promoter gases, and the like.
The subject methods and systems provide for a number of advantages. First, the subject methods provide for extremely high CO2 removal rates and separation ratios from the multicomponent gaseous stream. In many embodiments, the CO2 separation ratio exceeds about 75%. In yet other embodiments, the CO2 removal rate may exceed about 90% or even 95%in many embodiments. These exceptional recovery rates are observed at low CO2 partial pressures, e.g. partial pressures that are less than about 5 atm in many embodiments as low as 1 to 2 atm or lower. Although the above discussion has focused on the reduction of minimum CO2 hydrate formation pressure by utilizing gaseous and/or liquid hydrate promoters, the above described approach can be utilized to reduce the minimum hydrate formation pressure of many hydrate forming gases, including methane, ethane, propane, butane, or mixtures of these gases, including natural gas, to separate or fractionate specific gaseous species utilizing hydrate formation as the thermodynamic foundation of the separation and/or hydrate formation process.
It is evident from the above discussion that a simple and efficient method for the selective removal of CO2 from a multicomponent gaseous stream is provided. By using a CO2 hydrate promoter in the multicomponent gaseous stream, one can obtain high single- pass CO2 separation ratios at low CO2 partial pressures, even at temperatures ranging from 0 to 1 °C. As such, the subject invention represents a significant contribution to the art. All publications and patent applications cited in this specification are herein incorporated by reference as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference.
Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it will be readily apparent to those of ordinary skill in the art in light of the teachings of this invention that certain changes and modifications may be made thereto without departing from the spirit or scope of the appended claims.

Claims

WHAT IS CLAIMED IS:
1. A method for removing CO2 from a multicomponent gaseous stream to produce a CO2 depleted gaseous stream, said method comprising:
(a) providing a multicomponent gaseous stream; (b) contacting said multicomponent gaseous stream with an aqueous fluid under conditions sufficient to produce CO2 hydrates, whereby CO2 is removed from said gaseous stream by said aqueous fluid and concomitantly fixed as CO2 clathrates upon said contacting to produce a CO2 depleted gaseous stream and a CO2 clathrate slurry; and
(c) separating said CO2 depleted gaseous stream from said CO2 clathrate slurry; with the proviso that a CO2 hydrate promoter is present in at least one of said multicomponent gaseous stream and said aqueous fluid; whereby CO2 is removed from a multicomponent gaseous stream.
2. The method according to Claim 1, wherein said CO2 hydrate promoter is present in in an amount sufficient to reduce the CO2 partial pressure requirement and/or increase the temperature of hydrate formation under said conditions as compared to a control.
3. The method according to Claim 2, wherein said conditions comprise a temperature of about -1.5 to 10°C.
4. The method according to Claim 1, wherein said aqueous fluid is CO2 nucleated water.
5. The method according to Claim 1, wherein a CO2 hydrate promoter is present in both said multicomponent gaseous stream and said aqueous fluid.
6. A method for removing CO2 from a multicomponent gaseous stream to produce a CO2 depleted gaseous stream, said method comprising:
(a) providing a multicomponent gaseous stream; (b) contacting said multicomponent gaseous stream with CO2 nucleated water under conditions sufficient to produce CO2 hydrates, whereby CO2 is removed from said gaseous stream and concomitantly fixed as CO2 clathrates upon said contacting to produce a CO2 depleted gaseous stream and a CO clathrate slurry; and (c) separating said CO2 depleted gaseous stream from said CO2 clathrate slurry; with the proviso that at least one of said gaseous stream and said nucleated water contains a CO2 hydrate promoter, wherein said CO2 hydrate promoter is present in an amount sufficient to reduce the CO2 partial pressure requirement and/or increase the temperature of hydrate formation at 0°C as compared to a control; whereby CO2 is removed from a multicomponent gaseous stream.
7. The method according to Claim 6, wherein said CO2 partial pressure requirement of hydrate formation in the presence of said CO2 hydrate promoter does not exceed about 9 atm.
8. The method according to Claim 6, wherein said CO2 hydrate promoter is a low molecular weight compound.
9. The method according to Claim 8, wherein said low molecular weight compound is a halogenated hydrocarbon.
10. The method according to Claim 8, wherein said low molecular weight compound is a sulfur containing compound.
11. The method according to Claim 8, wherein said low molecular weight compound is an organic salt.
12. The method according to Claim 6, wherein said contacting occurs at a temperature ranging from about 0.5 to 3 °C.
13. The method according to Claim 6, wherein said contacting occurs at a system pressure ranging from about 3 to 200 atm.
14. A method for removing CO2 from a multicomponent gaseous stream to produce a CO2 depleted gaseous stream, said method comprising:
(a) providing a multicomponent gaseous stream comprising a CO2 hydrate promoter, wherein said CO2 hydrate promoter is a compound that has a low vapor pressure at its hydrate formation temperature, wherein said CO2 hydrate promoter is present in an amount sufficient to provide for CO2 hydrate formation at a CO2 partial pressure of less than about 9 atm at about 0 °C;
(b) contacting said multicomponent gaseous stream with CO2 nucleated water under conditions sufficient to produce CO2 hydrates, whereby CO2 is removed from said gaseous stream and concomitantly fixed as CO2 clathrates upon said contacting to produce a CO2 depleted gaseous stream and a CO2 clathrate slurry, wherein said CO2 nucleated water optionally contains a CO2 hydrate promoter; and
(c) separating said CO2 depleted gaseous stream from said CO2 clathrate slurry; whereby CO2 is removed from a multicomponent gaseous stream.
15. The method according to Claim 14, wherein said CO2 hydrate promoter in said multicomponent gaseous stream is a low molecular weight compound.
16. The method according to Claim 15, wherein said low molecular weight compound is a sulfur containing compound.
17. The method according to Claim 16, wherein said sulfur containing compound is selected from the group consisting of H2S, SO2 and CS2.
18. The method according to Claim 14, wherein said contacting occurs at a temperature ranging from about 0.5 to 3 °C.
19. The method according to Claim 13, wherein said contacting occurs at a system pressure ranging from about 3 to 200 atm.
20. The method according to Claim 13, wherein said method has a single-pass CO2 separation raito of at least about 50%.
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2382040A (en) * 2001-09-14 2003-05-21 Chevron Usa Inc Scrubbing CO2 from a gas stream containing methane and CO2 .
WO2011114168A1 (en) * 2010-03-19 2011-09-22 The Queen's University Of Belfast Removal of carbon dioxide from a gas stream by using aqueous ionic liquid

Families Citing this family (78)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080072495A1 (en) * 1999-12-30 2008-03-27 Waycuilis John J Hydrate formation for gas separation or transport
KR100347092B1 (en) * 2000-06-08 2002-07-31 한국과학기술원 Method for Separation of Gas Mixtures Using Hydrate Promoter
US6797039B2 (en) * 2002-12-27 2004-09-28 Dwain F. Spencer Methods and systems for selectively separating CO2 from a multicomponent gaseous stream
US6946017B2 (en) * 2003-12-04 2005-09-20 Gas Technology Institute Process for separating carbon dioxide and methane
US7128777B2 (en) 2004-06-15 2006-10-31 Spencer Dwain F Methods and systems for selectively separating CO2 from a multicomponent gaseous stream to produce a high pressure CO2 product
US9028607B2 (en) * 2005-02-24 2015-05-12 Wisconsin Electric Power Company Carbon dioxide sequestration in foamed controlled low strength materials
US7390444B2 (en) * 2005-02-24 2008-06-24 Wisconsin Electric Power Company Carbon dioxide sequestration in foamed controlled low strength materials
CN101258218B (en) * 2005-08-09 2012-11-28 埃克森美孚研究工程公司 Tetraorganoammonium and tetraorganophosphonium salts for acid gas scrubbing process
US20070248527A1 (en) * 2006-04-25 2007-10-25 Spencer Dwain F Methods and systems for selectively separating co2 from an oxygen combustion gaseous stream
CN100493672C (en) * 2006-11-10 2009-06-03 中国科学院广州能源研究所 Hydrate process and apparatus for separating gas mixture continuously
US7753618B2 (en) * 2007-06-28 2010-07-13 Calera Corporation Rocks and aggregate, and methods of making and using the same
EA200901629A1 (en) 2007-06-28 2010-06-30 Калера Корпорейшн METHODS AND DESCRIPTION SYSTEMS INCLUDING THE DECOMPOSITION OF CARBONATE COMPOUNDS
EP2058045A3 (en) * 2007-11-02 2011-02-02 Yoosung Co., Ltd. Separation, purification and recovery method of SF6, HFCs and PFCs
US7754169B2 (en) * 2007-12-28 2010-07-13 Calera Corporation Methods and systems for utilizing waste sources of metal oxides
BRPI0821515A2 (en) * 2007-12-28 2019-09-24 Calera Corp co2 capture methods
US20100239467A1 (en) * 2008-06-17 2010-09-23 Brent Constantz Methods and systems for utilizing waste sources of metal oxides
US7749476B2 (en) * 2007-12-28 2010-07-06 Calera Corporation Production of carbonate-containing compositions from material comprising metal silicates
US8479505B2 (en) 2008-04-09 2013-07-09 Sustainx, Inc. Systems and methods for reducing dead volume in compressed-gas energy storage systems
US8677744B2 (en) 2008-04-09 2014-03-25 SustaioX, Inc. Fluid circulation in energy storage and recovery systems
US8037678B2 (en) 2009-09-11 2011-10-18 Sustainx, Inc. Energy storage and generation systems and methods using coupled cylinder assemblies
US8359856B2 (en) 2008-04-09 2013-01-29 Sustainx Inc. Systems and methods for efficient pumping of high-pressure fluids for energy storage and recovery
US7832207B2 (en) * 2008-04-09 2010-11-16 Sustainx, Inc. Systems and methods for energy storage and recovery using compressed gas
US8240140B2 (en) 2008-04-09 2012-08-14 Sustainx, Inc. High-efficiency energy-conversion based on fluid expansion and compression
US7802426B2 (en) 2008-06-09 2010-09-28 Sustainx, Inc. System and method for rapid isothermal gas expansion and compression for energy storage
US8474255B2 (en) 2008-04-09 2013-07-02 Sustainx, Inc. Forming liquid sprays in compressed-gas energy storage systems for effective heat exchange
US7958731B2 (en) 2009-01-20 2011-06-14 Sustainx, Inc. Systems and methods for combined thermal and compressed gas energy conversion systems
US8250863B2 (en) 2008-04-09 2012-08-28 Sustainx, Inc. Heat exchange with compressed gas in energy-storage systems
US20110266810A1 (en) 2009-11-03 2011-11-03 Mcbride Troy O Systems and methods for compressed-gas energy storage using coupled cylinder assemblies
US8225606B2 (en) 2008-04-09 2012-07-24 Sustainx, Inc. Systems and methods for energy storage and recovery using rapid isothermal gas expansion and compression
US20100307156A1 (en) 2009-06-04 2010-12-09 Bollinger Benjamin R Systems and Methods for Improving Drivetrain Efficiency for Compressed Gas Energy Storage and Recovery Systems
US8448433B2 (en) 2008-04-09 2013-05-28 Sustainx, Inc. Systems and methods for energy storage and recovery using gas expansion and compression
US20100144521A1 (en) * 2008-05-29 2010-06-10 Brent Constantz Rocks and Aggregate, and Methods of Making and Using the Same
WO2010009273A1 (en) 2008-07-16 2010-01-21 Calera Corporation Co2 utilization in electrochemical systems
CN104722466A (en) 2008-07-16 2015-06-24 卡勒拉公司 Low-energy 4-cell Electrochemical System With Carbon Dioxide Gas
US7993500B2 (en) * 2008-07-16 2011-08-09 Calera Corporation Gas diffusion anode and CO2 cathode electrolyte system
US20100021361A1 (en) * 2008-07-23 2010-01-28 Spencer Dwain F Methods and systems for selectively separating co2 from a multi-component gaseous stream
EP2338136A1 (en) * 2008-09-11 2011-06-29 Calera Corporation Co2 commodity trading system and method
US7815880B2 (en) 2008-09-30 2010-10-19 Calera Corporation Reduced-carbon footprint concrete compositions
TW201026597A (en) 2008-09-30 2010-07-16 Calera Corp CO2-sequestering formed building materials
US7939336B2 (en) * 2008-09-30 2011-05-10 Calera Corporation Compositions and methods using substances containing carbon
US8869477B2 (en) 2008-09-30 2014-10-28 Calera Corporation Formed building materials
CN101925391A (en) * 2008-10-31 2010-12-22 卡勒拉公司 Non-cementitious compositions comprising CO2 sequestering additives
US9133581B2 (en) 2008-10-31 2015-09-15 Calera Corporation Non-cementitious compositions comprising vaterite and methods thereof
FR2938522B1 (en) * 2008-11-20 2010-12-17 Inst Francais Du Petrole PROCESS FOR THE PRODUCTION OF HYDROGEN WITH TOTAL CO2 CAPTATION AND RECYCLING OF NON-CONVERTED METHANE
US20100150802A1 (en) * 2008-12-11 2010-06-17 Gilliam Ryan J Processing co2 utilizing a recirculating solution
US7790012B2 (en) * 2008-12-23 2010-09-07 Calera Corporation Low energy electrochemical hydroxide system and method
CA2696088A1 (en) * 2008-12-23 2010-06-23 Calera Corporation Low-energy electrochemical proton transfer system and method
US20100258035A1 (en) * 2008-12-24 2010-10-14 Brent Constantz Compositions and methods using substances containing carbon
US20110091366A1 (en) * 2008-12-24 2011-04-21 Treavor Kendall Neutralization of acid and production of carbonate-containing compositions
EP2240629A4 (en) * 2009-01-28 2013-04-24 Calera Corp Low-energy electrochemical bicarbonate ion solution
US8834688B2 (en) 2009-02-10 2014-09-16 Calera Corporation Low-voltage alkaline production using hydrogen and electrocatalytic electrodes
WO2010101953A1 (en) 2009-03-02 2010-09-10 Calera Corporation Gas stream multi-pollutants control systems and methods
EP2247366A4 (en) * 2009-03-10 2011-04-20 Calera Corp Systems and methods for processing co2
US7963110B2 (en) 2009-03-12 2011-06-21 Sustainx, Inc. Systems and methods for improving drivetrain efficiency for compressed gas energy storage
JP5504675B2 (en) * 2009-03-31 2014-05-28 Jfeスチール株式会社 Gas separation method and gas separation equipment using membrane separation and hydrate separation
US8104274B2 (en) 2009-06-04 2012-01-31 Sustainx, Inc. Increased power in compressed-gas energy storage and recovery
US20110147227A1 (en) * 2009-07-15 2011-06-23 Gilliam Ryan J Acid separation by acid retardation on an ion exchange resin in an electrochemical system
US7993511B2 (en) * 2009-07-15 2011-08-09 Calera Corporation Electrochemical production of an alkaline solution using CO2
US20110079515A1 (en) * 2009-07-15 2011-04-07 Gilliam Ryan J Alkaline production using a gas diffusion anode with a hydrostatic pressure
US8191362B2 (en) 2010-04-08 2012-06-05 Sustainx, Inc. Systems and methods for reducing dead volume in compressed-gas energy storage systems
US8171728B2 (en) 2010-04-08 2012-05-08 Sustainx, Inc. High-efficiency liquid heat exchange in compressed-gas energy storage systems
US8234863B2 (en) 2010-05-14 2012-08-07 Sustainx, Inc. Forming liquid sprays in compressed-gas energy storage systems for effective heat exchange
US8709367B2 (en) 2010-07-30 2014-04-29 General Electric Company Carbon dioxide capture system and methods of capturing carbon dioxide
US8495872B2 (en) 2010-08-20 2013-07-30 Sustainx, Inc. Energy storage and recovery utilizing low-pressure thermal conditioning for heat exchange with high-pressure gas
US8578708B2 (en) 2010-11-30 2013-11-12 Sustainx, Inc. Fluid-flow control in energy storage and recovery systems
CN103492046B (en) 2011-01-20 2015-08-26 沙特阿拉伯石油公司 Used heat is used for CO 2car on reclaim and store reversible solid adsorption method and system
US9371755B2 (en) 2011-01-20 2016-06-21 Saudi Arabian Oil Company Membrane separation method and system utilizing waste heat for on-board recovery and storage of CO2 from motor vehicle internal combustion engine exhaust gases
EP2665808B1 (en) 2011-01-20 2016-12-07 Saudi Arabian Oil Company On-board recovery and storage of c02 from motor vehicle exhaust gases
WO2012100157A1 (en) 2011-01-20 2012-07-26 Saudi Arabian Oil Company Direct densification method and system utilizing waste heat for on-board recovery and storage of co2 from motor vehicle internal combustion engine exhaust gases
JP5477328B2 (en) * 2011-04-14 2014-04-23 Jfeエンジニアリング株式会社 Gas collection method and gas collection device
WO2012158781A2 (en) 2011-05-17 2012-11-22 Sustainx, Inc. Systems and methods for efficient two-phase heat transfer in compressed-air energy storage systems
US20130091834A1 (en) 2011-10-14 2013-04-18 Sustainx, Inc. Dead-volume management in compressed-gas energy storage and recovery systems
JP5477364B2 (en) * 2011-12-01 2014-04-23 Jfeエンジニアリング株式会社 Method and apparatus for collecting and releasing gas using a hydrate containing a quaternary ammonium salt as a guest molecule
JP5488573B2 (en) * 2011-12-05 2014-05-14 Jfeエンジニアリング株式会社 Gas collecting agent and gas collecting method
JP5783137B2 (en) * 2012-06-15 2015-09-24 信越化学工業株式会社 Sulfonium salt, polymer compound, resist material, and pattern forming method
CN103304479B (en) * 2013-05-28 2015-07-01 常州大学 Promoter for CO2 hydrate and application of promoter
CN106474904B (en) * 2016-11-25 2019-03-08 中国科学院广州能源研究所 A kind of CO of hydrate joint chemical absorption method2Gas fractionation unit and method
US11439858B1 (en) * 2019-08-14 2022-09-13 Dieter R. Berndt Fire extinguisher and method

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4821794A (en) * 1988-04-04 1989-04-18 Thermal Energy Storage, Inc. Clathrate thermal storage system
US5277038A (en) * 1992-08-28 1994-01-11 Instatherm Company Thermal storage system for a vehicle
US5562891A (en) * 1992-10-05 1996-10-08 The California Institute Of Technology Method for the production of carbon dioxide hydrates
US5700311A (en) * 1996-04-30 1997-12-23 Spencer; Dwain F. Methods of selectively separating CO2 from a multicomponent gaseous stream
US6028234A (en) * 1996-12-17 2000-02-22 Mobil Oil Corporation Process for making gas hydrates

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3150942A (en) 1959-10-19 1964-09-29 Chemical Construction Corp Method of purifying a hydrogen gas stream by passing said gas in series through 13x and 4a or 5a molecular sieves
US3479298A (en) 1964-08-04 1969-11-18 Lummus Co Production of hydrogen
US3359744A (en) 1965-06-16 1967-12-26 Air Prod & Chem Hydrogen purification system with separated vapor and liquid mixed to provide a heat exchange medium
GB1381112A (en) 1971-04-20 1975-01-22 Petrocarbon Dev Ltd Separation of gas mixtures
US4235607A (en) 1979-01-19 1980-11-25 Phillips Petroleum Company Method and apparatus for the selective absorption of gases
US4861351A (en) 1987-09-16 1989-08-29 Air Products And Chemicals, Inc. Production of hydrogen and carbon monoxide
DE69015326T2 (en) * 1989-11-21 1995-07-20 Mitsubishi Heavy Ind Ltd Method for fixing carbon dioxide and device for treating carbon dioxide.
JPH03164419A (en) 1989-11-21 1991-07-16 Mitsubishi Heavy Ind Ltd Treatment of gaseous carbon dioxide
US5148943A (en) 1991-06-17 1992-09-22 Hydreclaim Corporation Method and apparatus for metering and blending different material ingredients
US5159971A (en) * 1991-06-27 1992-11-03 Allied-Signal Inc. Cooling medium for use in a thermal energy storage system
US5434330A (en) 1993-06-23 1995-07-18 Hnatow; Miguel A. Process and apparatus for separation of constituents of gases using gas hydrates
US5536893A (en) * 1994-01-07 1996-07-16 Gudmundsson; Jon S. Method for production of gas hydrates for transportation and storage
US5600044A (en) 1994-09-15 1997-02-04 Exxon Production Research Company Method for inhibiting hydrate formation
FR2768637B1 (en) * 1997-09-25 1999-10-22 Inst Francais Du Petrole METHOD FOR TRANSPORTING HYDRATES IN SUSPENSION IN PRODUCTION EFFLUENTS

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4821794A (en) * 1988-04-04 1989-04-18 Thermal Energy Storage, Inc. Clathrate thermal storage system
US5277038A (en) * 1992-08-28 1994-01-11 Instatherm Company Thermal storage system for a vehicle
US5562891A (en) * 1992-10-05 1996-10-08 The California Institute Of Technology Method for the production of carbon dioxide hydrates
US5700311A (en) * 1996-04-30 1997-12-23 Spencer; Dwain F. Methods of selectively separating CO2 from a multicomponent gaseous stream
US6028234A (en) * 1996-12-17 2000-02-22 Mobil Oil Corporation Process for making gas hydrates

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP1283740A4 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2382040A (en) * 2001-09-14 2003-05-21 Chevron Usa Inc Scrubbing CO2 from a gas stream containing methane and CO2 .
GB2382040B (en) * 2001-09-14 2003-10-29 Chevron Usa Inc Scrubbing CO2 from methane-containing gases using an aqueous stream
US6667347B2 (en) 2001-09-14 2003-12-23 Chevron U.S.A. Inc. Scrubbing CO2 from methane-containing gases using an aqueous stream
WO2011114168A1 (en) * 2010-03-19 2011-09-22 The Queen's University Of Belfast Removal of carbon dioxide from a gas stream by using aqueous ionic liquid
US10888814B2 (en) 2010-03-19 2021-01-12 The Queen's University Of Belfast Removal of carbon dioxide from a gas stream by using aqueous ionic liquid

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