# US 5,700,311 A · Methods of selectively separating CO.sub.2 from a multicomponent gaseous stream > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,700,311 A - Document ID: US5700311A - Status: Granted - Kind: A - Application number: 08/643,151 - Filed: 1996-04-30 - Granted: 1997-12-23 - Earliest claimed: 1996-04-30 - Inventors: Dwain F. Spencer - Web page: https://patentgrep.com/patent/US5700311A ## CPC - B01D 53/1475: {Removing carbon dioxide} - C10L 3/10: Working-up natural gas or synthetic natural gas - C10L 3/102: {of acid contaminants} - C10L 3/108: {Production of gas hydrates} - B01D 2256/24: Hydrocarbons - B01D 2258/05: Biogas - Y02C 20/20: of methane - Y02C 20/40: of CO2 - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - C10L: FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS - Y02C: CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG] ## Abstract Methods are provided for the selective removal of CO.sub.2 from a multicomponent gaseous stream to provide a CO.sub.2 depleted gaseous stream having at least a reduction in the concentration of CO.sub.2 relative to the untreated multicomponent gaseous stream. In the subject methods, the multicomponent gaseous stream is contacted with CO.sub.2 nucleated water under conditions of selective CO.sub.2 clathrate formation, where the CO.sub.2 nucleated water serves as liquid solvent. The subject methods find use in a variety of applications where it is desired to selectively remove CO.sub.2 from a multicomponent gaseous stream, including chemical feedstock processing applications and air emissions control applications. ## Claims ### Claim 1 A method for removing CO.sub.2 from the multicomponent gaseous stream to produce a CO.sub.2 depleted gaseous stream, said method comprising: contacting said multicomponent gaseous stream with CO.sub.2 nucleated water under conditions of CO.sub.2 clathrate formation wherein the temperature ranging from -1.5.degree. to 10.degree. C. and the pressure ranges from at least about 6 atm to 20 atm, whereby CO.sub.2 is absorbed from said gaseous stream by said CO.sub.2 nucleated water and concomitantly fixed as CO.sub.2 clathrates upon said contacting, whereby a CO.sub.2 depleted gaseous stream and a CO.sub.2 clathrate slurry are produced; and separating said CO.sub.2 depleted gaseous stream from said CO.sub.2 clathrate slurry. ### Claim 2 (depends on 1) The method according to claim 1, wherein the temperature of said conditions of CO.sub.2 clathrate formation ranges from -1.5.degree. to 10.degree. C. ### Claim 3 (depends on 1) The method according to claim 1, wherein the pressure of said conditions of CO.sub.2 clathrate formation is at least about 10 atm. ### Claim 4 (depends on 1) The method according to claim 1, wherein said CO.sub.2 nucleated water has a CO.sub.2 mole fraction of between about 0.01 to 0.04. ### Claim 5 A method for selectively removing CO.sub.2 from a multicomponent gaseous stream to produce a CO.sub.2 depleted gaseous stream, said method comprising: contacting said multicomponent gaseous stream with CO.sub.2 nucleated water under conditions of selective CO.sub.2 clathrate formation wherein the temperature ranges from about -1.5.degree. to 10.degree. C. and the pressure ranges from about 10 to 20 atm, whereby CO.sub.2 is absorbed from said gaseous stream by said CO.sub.2 nucleated water and concomitantly fixed as CO.sub.2 clathrates upon said contacting, whereby a CO.sub.2 depleted gaseous stream and a CO.sub.2 clathrate slurry are produced; and separating said CO.sub.2 depleted gaseous stream from said CO.sub.2 clathrate slurry. ### Claim 6 (depends on 5) The method according to claim 5, wherein said contacting of said multicomponent gaseous stream and CO.sub.2 nucleated water reduces the concentration of said CO.sub.2 in said multicomponent gaseous stream by at least about 50%. ### Claim 7 (depends on 5) The method according to claim 5, wherein said method further comprises sequestering said CO.sub.2 clathrate slurry. ### Claim 8 (depends on 5) The method according to claim 5, wherein said multicomponent gaseous stream is selected from the group of multicomponent gaseous streams consisting of power plant flue gas, turbo charged boiler emission gas, coal gasification product gas, shifted coal gasification product gas, and anaerobic digester product gas. ### Claim 9 A method for selectively removing CO.sub.2 from shifted coal gasification product gas to produce CO.sub.2 depleted shifted coal gasification product gas, said method comprising: reducing the temperature of said coal gasification product gas to a range of from about -1.5.degree. to 10.degree. C.; contacting said reduced temperature coal gasification product gas with CO.sub.2 nucleated water under conditions of selective CO.sub.2 clathrate formation wherein the temperature ranges from about -1.5.degree. to 10.degree. C. and the pressure ranges from about 10 to 20 atm, whereby CO.sub.2 is absorbed from said gaseous stream by said CO.sub.2 nucleated water and concomitantly fixed as CO.sub.2 clathrates upon said contacting, whereby a CO.sub.2 depleted shifted coal gasification product gas and a CO.sub.2 clathrate slurry are produced; and separating said CO.sub.2 depleted shifted coal gasification product gas from said CO.sub.2 clathrate slurry. ### Claim 10 (depends on 9) The method according to claim 9, wherein said method further comprises sequestering said CO.sub.2 clathrate slurry.