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An energy-efficient method of recovering carbon dioxide (CO2) in a high-pressure liquid state from a high-pressure gas stream. The method includes cooling, condensing, and/or separating CO2 from a high-pressure gas stream in two or more separation zones and further purifying the resulting sub-critic

An energy-efficient method of recovering carbon dioxide (CO2) in a high-pressure liquid state from a high-pressure gas stream. The method includes cooling, condensing, and/or separating CO2 from a high-pressure gas stream in two or more separation zones and further purifying the resulting sub-critical pressure liquid CO2 streams in a third purification zone to thereby provide purified CO2. The purified liquid CO2 may be pumped to above the critical pressure for further utilization and/or sequestration for industrial or environmental purposes.

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1. A method of recovering carbon dioxide (CO2) in a liquid state from a high-pressure gas stream, said method comprising: (a) cooling and partially condensing a high-pressure feed gas stream to thereby provide a condensed CO2-rich fraction and an uncondensed CO2-lean fraction;(b) recovering a CO2-ri

1. A method of recovering carbon dioxide (CO2) in a liquid state from a high-pressure gas stream, said method comprising: (a) cooling and partially condensing a high-pressure feed gas stream to thereby provide a condensed CO2-rich fraction and an uncondensed CO2-lean fraction;(b) recovering a CO2-rich liquid stream from at least a portion of said uncondensed CO2-lean fraction wherein said recovering comprises one or more of the following steps— (i) absorbing CO2 from said uncondensed CO2-lean fraction, and/or(ii) adsorbing CO2 from said uncondensed CO2-lean fraction, and/or(iii) freezing CO2 from said uncondensed CO2-lean fraction;(c) combining at least a portion of said CO2-rich liquid stream recovered in step (b) with at least a portion of said condensed CO2-rich fraction to thereby provide a combined CO2-rich stream; and(d) fractionating at least a portion of said combined CO2-rich stream to separate non-CO2 components therefrom and thereby provide a purified CO2-rich liquid stream,wherein said high-pressure feed gas stream has a pressure of at least 60.4 psia, wherein said condensed CO2-rich fraction and said combined CO2-rich stream are liquid streams, wherein said purified CO2-rich liquid stream has a pressure of at least 100 psia. 2. The process of claim 1, wherein said condensed CO2-rich fraction has a pressure of at least 650 psia and said combined CO2-rich stream has a pressure of at least 500 psia. 3. The process of claim 1, further comprising injecting said purified CO2-rich liquid stream into a geological formation at a pressure greater than the average formation pressure of said geological formation. 4. The process of claim 1, wherein said high-pressure feed gas stream comprises a natural gas stream or a synthesis gas stream. 5. The process of claim 1, wherein said high-pressure feed gas stream has a pressure of at least 350 psia and comprises at least 20 mole percent CO2 prior to said cooling of step (a). 6. The process of claim 1, wherein said high-pressure feed gas stream comprises water in an amount not more than 50 ppm by volume and less than 1 mole percent of one or more sulfur-containing compounds. 7. The process of claim 1, wherein said condensed CO2-rich fraction comprises at least 10 percent of the total CO2 originally present in said high-pressure feed gas stream and said uncondensed CO2-lean fraction comprises at least about 50 percent of the total non-CO2 components originally present in said high-pressure feed gas stream. 8. The process of claim 1, wherein the pressure of said uncondensed CO2-lean fraction is within 200 pounds per square inch, (psi) of the pressure of said high-pressure feed gas stream prior to said cooling of step (a). 9. The process of claim 1, wherein at least a portion of said cooling of step (a) is provided by a cascade refrigeration system, a mixed refrigeration system, an acoustic refrigeration system, and/or an absorption refrigeration system. 10. The process of claim 1, wherein said recovering of step (b) comprises adsorbing and/or absorbing CO2 from said uncondensed CO2-lean fraction to thereby produce a CO2-rich gaseous stream, wherein said recovering of step (b) includes compressing and/or cooling said CO2-rich gaseous stream to form said CO2-rich liquid stream having a pressure of at least 100 psig. 11. The process of claim 1, wherein said recovering of step (b) comprises adsorbing CO2 from said uncondensed CO2-lean fraction using a solid adsorbent material, wherein said adsorbing produces a CO2-rich tail gas stream, wherein said recovering of step (b) comprises compressing and/or cooling at least a portion of said CO2-rich tail gas stream to thereby provide said CO2-rich liquid stream. 12. The process of claim 1, wherein said recovering of step (b) comprises absorbing CO2 from said uncondensed CO2-lean fraction using a circulating liquid solvent, wherein said absorbing produces a CO2-rich off-gas stream, wherein said recovering of step (b) comprises compressing and/or cooling at least a portion of said recovered CO2-rich off-gas stream to thereby provide said CO2-rich liquid stream. 13. The process of claim 12, wherein said circulating liquid solvent is selected from a group consisting of methanol, SELEXOL solvent (DEPG), PURISOL solvent (NMP), MORPHYSORB solvent (NFM and NAM), Sulfinol solvent (Solfolane and di-isopropanolamine or Solfolane and methyldiethanolamine), reversible ionic liquids, propylene carbonate, hot potassium carbonate, amines, chilled ammonia, ammonium carbonate, and combinations thereof. 14. The process of claim 1, wherein said recovering of step (b) comprises freezing CO2 from said uncondensed CO2-lean fraction to thereby provide a plurality of CO2 solids and melting at least a portion of said CO2 solids to thereby provide said CO2-rich liquid stream. 15. The process of claim 1, further comprising, prior to said cooling of step (a), passing at least a portion of said high-pressure gas stream through at least one membrane separation device to thereby provide a first permeate stream and a first CO2-enriched non-permeate stream, wherein said high-pressure feed gas stream at least partially condensed in step (a) comprises at least a portion of said first CO2-enriched non-permeate stream. 16. A method of recovering carbon dioxide (CO2) in a liquid state from a high-pressure gas stream, said method comprising: (a) cooling and partially condensing a high-pressure feed gas stream to thereby provide a condensed CO2-rich fraction and an uncondensed CO2-lean fraction;(b) recovering a CO2-rich liquid stream from at least a portion of said uncondensed CO2-lean fraction, wherein said recovering comprises one or more of the following steps— (i) absorbing CO2 from said uncondensed CO2-lean fraction using a circulating liquid solvent to thereby provide a CO2-rich off-gas stream, wherein said recovering further comprises compressing and/or cooling at least a portion of said recovered CO2-rich off-gas stream to thereby provide said CO2-rich liquid stream, and/or(ii) adsorbing CO2 from said uncondensed CO2-lean fraction using a solid adsorbent material to thereby provide a CO2-rich tail gas stream, wherein said CO2-rich liquid stream recovered comprises at least a portion of said CO2-rich tail gas stream, and/or(iii) freezing CO2 from said uncondensed CO2-lean fraction using one or more direct or indirect heat exchange methods to thereby provide a plurality of CO2 solids and melting at least a portion of said CO2 solids to thereby provide said CO2-rich liquid stream;(c) introducing at least a portion of said CO2-rich liquid stream recovered in step (b) and/or at least a portion of said condensed CO2-rich fraction resulting from said cooling and partially condensing of step (a) into a purification zone; and(d) separating at least a portion of the non-CO2 components from said CO2-rich liquid stream and/or said condensed CO2-rich fraction introduced into said purification zone to thereby provide a purified CO2-rich liquid stream,wherein each of said high-pressure feed gas stream, said condensed CO2-rich fraction, and said purified CO2-rich liquid stream has a pressure greater than 77 psia. 17. The process of claim 16, wherein said high-pressure feed gas stream comprises a natural gas or a synthesis gas stream. 18. The process of claim 16, wherein said purified CO2 liquid stream comprises at least 75 percent of the CO2 originally present in said high-pressure feed gas stream. 19. The process of claim 16, wherein not more than 90 percent of the CO2 present in said purified CO2-rich liquid stream was subjected to compression during said recovering of step (b). 20. The process of claim 16, wherein said high-pressure feed gas stream has a pressure of at least 350 psia and comprises at least 20 mole percent CO2 prior to said cooling of step (a), wherein said high-pressure feed gas stream has been pre-treated for the removal of non-methane hydrocarbons, sulfur-containing compounds, and water prior to said cooling of step (a). 21. The process of claim 16, wherein said recovering of step (b) comprises adsorbing CO2 from said uncondensed CO2-lean fraction, wherein said CO2-rich liquid stream recovered in step (b) has a pressure of at least 77 psia. 22. The process of claim 16, wherein said recovering of step (b) comprises absorbing CO2 from said uncondensed CO2-lean fraction wherein said CO2-rich liquid stream has a pressure of at least 77 psia, wherein said circulating liquid solvent is selected from a group consisting of methanol, SELEXOL solvent (DEPG), PURISOL solvent (NMP), MORPHYSORB solvent (NFM and NAM), Sulfinol solvent (Solfolane and di-isopropanolamine or Solfolane and methyldiethanolamine), Flexsorb SE solvent (Solfolane and sterically-hindered amine), reversible ionic liquids, propylene carbonate, hot potassium carbonate, amines, chilled ammonia, ammonium carbonate, and combinations thereof. 23. The process of claim 16, wherein said recovering of step (b) comprises freezing said CO2 from said uncondensed CO2-lean fraction, wherein said CO2-rich liquid stream has a pressure of at least 77 psia. 24. The process of claim 16, further comprising, prior to said cooling of step (a), passing at least a portion of said high-pressure gas stream through at least one membrane separation device to thereby provide a first permeate stream and a first CO2-enriched non-permeate stream, wherein said high-pressure feed gas stream at least partially condensed in step (a) comprises at least a portion of said first CO2-enriched non-permeate stream. 25. A method of recovering carbon dioxide (CO2) in a liquid state from a high-pressure gas stream, said method comprising: (a) cooling and partially condensing a high-pressure feed gas stream to thereby provide a condensed CO2-rich fraction and an uncondensed CO2-lean fraction;(b) passing at least a portion of said uncondensed CO2-lean fraction though at least one membrane separation device to thereby provide a second permeate stream and a second CO2-enriched non-permeate stream(c) recovering a CO2-rich liquid stream from at least a portion of said second CO2-enriched non-permeate stream, wherein said recovering comprises one or more of the following steps— (i) absorbing CO2 from said uncondensed CO2-lean fraction, and/or(ii) adsorbing CO2 from said uncondensed CO2-lean fraction, and/or(iii) freezing CO2 from said uncondensed CO2-lean fraction;(d) introducing at least a portion of said CO2-rich liquid stream recovered in step (d) and/or at least a portion of said condensed CO2-rich fraction resulting from said cooling and partially condensing of step (a) into a purification zone; and(e) separating at least a portion of the non-CO2 components from said CO2-rich liquid stream and/or said condensed CO2-rich fraction introduced into said purification zone to thereby provide a purified CO2-rich liquid stream,wherein each of said high-pressure feed gas stream, said condensed CO2-rich fraction, and said purified CO2-rich liquid stream has a pressure greater than 77 psia.