Scrubbing CO2 from a CO2-containing gas with an aqueous stream

• US 6,720,359 B2
• Filed: 09/14/2001
• Issued: 04/13/2004
• Est. Priority Date: 09/14/2001
• Status: Expired due to Fees

• Current Assignee: Chevron USA Incorporated (Chevron Corp.)
• Original Assignee: Chevron USA Incorporated (Chevron Corp.)
• Inventors: Munson, Curtis, OʼRear, Dennis J.
• Primary Examiner(s): Parsa, J.
• Application Number:
  US09/951,553
• Publication Number:
  US 20030055117A1
• Time in Patent Office: 942 Days
• Field of Search: 518/700, 518/702, 951/50, 166/267
• US Class Current: 518/702
• CPC Class Codes: C10G 2/30 from carbon monoxide with hydrogen
• CPC Class Codes: Y02C 20/20 of methane
• CPC Class Codes: Y02C 20/40 of CO2
• CPC Class Codes: Y02P 20/582 Recycling of unreacted starting or intermediate materials

Abstract

A process for removing CO₂ from a CO₂-containing gas. The process includes scrubbing CO₂ from a CO₂-containing gas using an aqueous phase liquid forming a CO₂-enriched aqueous phase. The CO₂-enriched aqueous phase is then disposed of in at least one of a marine environment, a terrestrial formation or combination thereof.

Claims

1. A process for removing CO₂ from a CO₂-containing gas, the process comprising:

a) scrubbing CO₂ from a CO₂-containing gas using an aqueous phase liquid, forming a CO₂-enriched aqueous phase, wherein the aqueous phase liquid is at a pressure greater than about atmospheric pressure and wherein the aqueous phase liquid has a pH of at least about 7.0 before scrubbing; and

b) disposing of the CO₂-enriched aqueous phase in at least one of a marine environment, a terrestrial formation or combination thereof, wherein disposal of the CO₂-enriched aqueous phase is done at a temperature, pressure, and pH sufficient to ensure that about 75% or more of the CO₂ removed from the CO₂-containing gas remains dissolved in the aqueous phase.

2. The process of claim 1, wherein the CO₂-containing gas is present in a Fischer-Tropsch GTL process stream.

3. The process of claim 1, wherein about 90% or more of the CO₂ removed from the CO₂-containing gas remains dissolved in the aqueous phase.

4. The process of claim 1, wherein said aqueous phase liquid is selected from the group consisting of sea water, reaction water generated during a Fischer-Tropsch process, spent cooling water from a Fischer-Tropsch process, river water, non-potable water sources, water recovered from crude or gas production, and combinations thereof.

5. The process of claim 1, wherein the terrestrial formation is selected from the group consisting of a hydrocarbonaceous formation, that is the same as or different from a source providing the methane-containing gas, a non-hydro carbonaceous formation or combination thereof.

6. The process of claim 1, wherein the CO₂-containing gas is an exhaust gas from a furnace.

18. The process of claim 1, further comprising adjusting the pH of the aqueous phase liquid with a basic material prior to scrubbing CO₂ from the CO₂-containing gas.

19. The process of claim 18, wherein the pH is adjusted by adding an alkali material, adding ammonia, adding a base, or combinations thereof.

20. The process of claim 1, further comprising de-aerating the aqueous phase liquid prior to scrubbing CO₂ from the CO₂-containing gas.

7. A process for converting methane-containing gas in a Fischer-Tropsch GTL process into liquid hydrocarbons, the process comprising:

a) converting methane-containing gas into synthesis gas;

b) converting at least a portion of the synthesis gas into liquid hydrocarbons and CO₂-containing gas;

c) scrubbing CO₂ from the CO₂-containing gas using an aqueous phase liquid, forming a CO₂-enriched aqueous phase wherein during scrubbing the aqueous phase liquid is at a pressure greater than about atmospheric pressure and wherein the aqueous phase liquid has a pH of at least 7.0 before scrubbing; and

d) disposing of the CO₂-enriched aqueous phase in at least one of a marine environment, a terrestrial formation or combination thereof wherein disposal of the CO₂-enriched aqueous phase is done at a temperature, pressure and pH sufficient to ensure that about 75% or more of the CO₂ removed from the CO₂-containing gas remains dissolved in the aqueous phase.

8. The process of claim 7, wherein about 90% or more of the CO₂ removed from the CO₂-containing gas remains dissolved in the aqueous phase.

9. The process of claim 7, wherein the aqueous phase liquid is selected from the group consisting of sea water, reaction water generated during a Fischer-Tropsch process, spent cooling water from a Fischer-Tropsch process, river water, non-potable water sources, water recovered from crude or gas production and combinations thereof.

10. The process of claim 7, wherein a pH of the aqueous phase liquid is adjusted to at least about 7.0 before scrubbing using a process selected from the group consisting essentially of oxidation, distillation, neutralization, extraction, ion exchange and combinations thereof.

11. The process of claim 7, wherein scrubbing with the aqueous phase liquid is conducted by contacting the CO₂-containing gas with a CO₂-selective adsorbent, treating the CO₂-selective adsorbent to form a CO₂-enriched gas stream and thereafter contacting the CO₂-enriched gas stream with the aqueous phase liquid.

12. The process of claim 7, wherein the terrestrial formation is selected from the group consisting essentially of a hydrocarbonaceous formation, that is the same as or different from a source providing the methane-containing gas, a non-hydrocarbonaceous formation and combinations thereof.

13. A process for removing CO₂ from a CO₂-containing gas, the process comprising:

a) scrubbing CO₂ from a CO₂-containing gas, present in a Fischer-Tropsch GTL process stream and/or a furnace exhaust gas, using an aqueous phase liquid at a pressure greater than about atmospheric pressure wherein the aqueous phase liquid has a pH of at least about 7.0 before scrubbing; and

b) disposing of the CO₂-enriched aqueous phase in at least one marine environment, a terrestrial formation, or combination thereof at a temperature, pressure and pH sufficient to ensure that at least about 75% of the CO₂ removed from the CO₂-containing gas remains in the aqueous phase.

14. A process for converting methane-containing gas generated form a Fischer-Tropsch GTL process into liquid hydrocarbons, the process comprising:

a) converting methane-containing gas into synthesis gas;

b) converting at least a portion of the methane-containing gas into liquid hydrocarbons and by-product CO₂-containing gas by a Fischer-Tropsch process;

c) scrubbing CO₂ from the CO₂-containing gas using an aqueous phase liquid at a pressure greater about atmospheric pressure, forming a CO₂-enriched aqueous phase wherein the aqueous phase liquid comprises water selected from the group consisting of reaction water generated during the FischerTropsch process, spent cooling water from the Fischer-Tropsch process, and mixtures thereof; and

d) disposing of the CO₂-enriched aqueous phase in at least one of a marine environment, a terrestrial formation or combination thereof at a temperature, pressure and pH sufficient to ensure that at least about 75% of the CO₂ removed from the CO₂-containing gas remains dissolved in the aqueous phase.

15. The process of claim 14, further comprising isolating at least a portion of the reaction water generated during the Fischer-Tropsch process, the spent cooling water from the Fischer-Tropsch process or mixtures thereof to provide an aqueous phase liquid to scrub CO₂ from the CO₂-containing gas.

16. The process of claim 14, wherein prior to contact with the by-product CO₂-containing gas, the aqueous phase liquid has a pH of at least about 7.0.

17. The process of claim 16, further comprising adjusting the pH of the aqueous phase liquid by adding an alkali material, adding ammonia, adding a base, or combinations thereof.