Process for treating carbon dioxide containing gas

• US 8,435,479 B2
• Filed: 08/23/2012
• Issued: 05/07/2013
• Est. Priority Date: 09/27/2002
• Status: Active Grant

• Current Assignee: Saipem SPA (Saipem)
• Original Assignee: CO2 Solutions Inc.
• Inventors: Fradette, Sylvie, Ruel, Jean
• Primary Examiner(s): Johnson, Edward
• Application Number:
  US13/592,422
• Publication Number:
  US 20130011897A1
• Time in Patent Office: 257 Days
• Field of Search: 423/432, 60/395, 607/72
• US Class Current: 423/432
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 53/84 Biological processes
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02C 20/40 of CO2
• CPC Class Codes: Y02E 20/32 Direct CO2 mitigation

Abstract

A process is disclosed for recycling carbon dioxide emissions from a fossil-fuel power plant into useful carbonated species The process primarily comprises the steps of: a) burning the fossil fuel, thereby generating heat and a hot exhaust gas containing CO₂; and b) converting the heat into energy. The process is characterized in that it further comprises the steps of: c) cooling the exhaust gas; and d) biologically transforming the CO₂ contained in the cooled exhaust gas into carbonated species, thereby obtaining a low CO₂ exhaust gas and producing useful carbonated species. The low CO₂ exhaust gas obtained in step d) can be released in the atmosphere without increasing the problem of greenhouse effect.

Claims

1. A process comprising:

a) combustion of a fossil fuel or biomass, thereby generating heat and a hot exhaust gas containing CO₂;

b) using said heat to produce steam from water in a steam generator;

c) cooling at least a portion of said exhaust gas to produce a cooled exhaust gas; and

d) reducing the amount of CO₂ contained in the cooled exhaust gas, thereby obtaining a low CO₂ exhaust gas, wherein the step of reducing the amount of CO₂ comprises;

contacting an aqueous liquid phase with the cooled exhaust gas to cause at least a portion of the CO₂ to dissolve into the aqueous liquid phase and catalyzing the hydration of at least a portion of the dissolved CO₂ and producing a solution containing hydrogen ions and bicarbonate ions; and

wherein said hydration is catalyzed by carbonic anhydrase or an analogue thereof.

2. The process of claim 1, wherein the enzyme carbonic anhydrase or the analogue thereof is free in the aqueous liquid phase.

3. The process of claim 1, wherein the enzyme carbonic anhydrase or the analogue thereof is immobilised on a support which is in suspension in the aqueous liquid phase.

4. The process of claim 1, wherein the enzyme carbonic anhydrase or the analogue thereof is entrapped inside a solid.

5. The process of claim 4, where the solid comprises a solid matrix.

6. The process of claim 1, wherein the enzyme carbonic anhydrase or the analogue thereof is entrapped inside a matrix or immobilized on supports which are mounted within a reactor.

7. The process of claim 1, wherein the steam produced in step b) is used to produce electricity.

8. The process of claim 7, wherein the steam produced in step b) is provided to a heat recovery steam generator system.

9. The process of claim 1, wherein step d) comprises adding cations to the solution and adjusting the pH of the solution to precipitate a carbonated species of the cation.

10. The process of claim 9, wherein the cations are selected from the group consisting of calcium, barium, magnesium and sodium ions.

11. The process of claim 1, wherein the step of reducing the amount of CO₂ in the cooled exhaust gas comprises biologically removing said CO₂.

12. A process comprising:

combustion of a fossil fuel or biomass, thereby generating heat and a CO₂ containing exhaust gas;

using said heat to produce steam from water in a steam generator;

reducing the amount of CO₂ contained in the CO₂ containing exhaust gas, thereby obtaining a low CO₂ gas, comprising contacting an aqueous liquid phase with the CO₂ containing exhaust gas to cause at least a portion of the CO₂ to dissolve into the aqueous liquid phase and catalyzing the hydration of at least a portion of the dissolved CO₂ and producing a solution containing hydrogen ions and bicarbonate ions; and

wherein the hydration is catalyzed by carbonic anhydrase or an analogue thereof.

13. The process of claim 12, wherein the enzyme carbonic anhydrase or the analogue thereof is free in the aqueous liquid phase.

14. The process of claim 12, wherein the enzyme carbonic anhydrase or the analogue thereof is immobilised on a support which is in suspension in the aqueous liquid phase.

15. The process of claim 12, wherein the enzyme carbonic anhydrase or the analogue thereof is entrapped inside a solid.

16. The process of claim 15, where the solid comprises a solid matrix.

17. The process of claim 12, wherein the enzyme carbonic anhydrase or the analogue thereof is entrapped inside a matrix or immobilized on supports which are mounted within a reactor.

18. The process of claim 12, comprising adding cations to the solution and adjusting the pH of the solution to precipitate a carbonated species of the cation.

19. The process of claim 12, wherein the cations are selected from the group consisting of calcium, barium, magnesium and sodium ions.

20. The process of claim 12, wherein the CO₂ containing gas comprises exhaust gas generated by combustion of fossil fuel or biomass.

21. A process comprising:

pre-treating a CO₂ containing gas to remove contaminants and produce a contaminant reduced gas;

reducing the amount of CO₂ contained in the contaminant reduced gas, thereby obtaining a low CO₂ gas, by contacting an aqueous liquid phase with the contaminant reduced gas to cause at least a portion of the CO₂ to dissolve into the aqueous liquid phase and catalyzing the hydration of at least a portion of the dissolved CO₂ and producing a solution containing hydrogen ions and bicarbonate ions; and

wherein the hydration is catalyzed by carbonic anhydrase or an analogue thereof.

22. The process of claim 21, wherein the contaminants removed are selected from the group consisting of ash, NO_x and SO₂.

23. The process of claim 21, wherein the pre-treating comprises scrubbing the CO₂ containing gas.

24. The process of claim 23, wherein the scrubbing is performed while cooling the CO₂ containing gas to produce a cooled CO₂ containing gas with a temperature sufficiently low to allow feeding directly into the step of biologically removing the CO₂.

25. The process of claim 21, wherein the CO₂ containing gas is cooled to a temperature sufficiently low so as to maintain a desired catalytic effect of the enzyme carbonic anhydrase or the analog thereof.

26. The process of claim 25, wherein the temperature to which the CO₂ containing gas is cooled avoids a given denaturing of free carbonic anhydrase.

27. The process of claim 25, wherein the temperature to which the CO₂ containing gas is cooled avoids a given denaturing of immobilized carbonic anhydrase.

28. The process of claim 21, wherein the enzyme carbonic anhydrase or the analogue thereof is free in the aqueous liquid phase;

immobilised on a support which is in suspension in the aqueous liquid phase;

entrapped inside a matrix which is in suspension in the aqueous liquid phase;

or entrapped inside a matrix or immobilized on supports which are mounted within a reactor.

29. The process of claim 21, comprising adding cations to the solution and adjusting the pH of the solution to precipitate a carbonated species of the cation.

30. The process of claim 29, wherein the cations are selected from the group consisting of calcium, barium, magnesium and sodium ions.

31. The process of claim 21, wherein the CO₂ containing gas comprises hot exhaust gas generated by combustion of fossil fuel or biomass.

32. The process of claim 31, wherein heat is removed from the hot exhaust gas prior to reducing the amount of CO₂ contained therein and the heat is recycled.

33. A process comprising:

generating a CO₂ containing gas;

ensuring that the CO₂ containing gas has a temperature sufficiently low so as to maintain a desired catalytic effect of carbonic anhydrase or analog thereof;

reducing the amount of CO₂ contained in the CO₂ containing gas, thereby obtaining a low CO₂ gas, comprising;

contacting an aqueous liquid phase with the CO₂ containing gas to cause at least a portion of the CO₂ to dissolve into the aqueous liquid phase and catalyzing the hydration of at least a portion of the dissolved CO₂ and producing a solution containing hydrogen ions and bicarbonate ions; and

wherein said hydration is catalyzed by the carbonic anhydrase or the analogue thereof.

34. The process of claim 33, wherein the CO₂ containing gas is subjected to a cooling step.

35. The process of claim 33, wherein the CO₂ containing gas comprises hot exhaust gas generated by combustion of fossil fuel or biomass and wherein heat is removed from the hot exhaust gas in a heat exchanger prior to reducing the amount of CO₂ contained therein.

36. A process comprising:

generating steam using heat derived from combustion;

cooling an exhaust gas containing CO₂ to produce a cooled exhaust gas, said exhaust gas being derived from the combustion;

reducing the amount of CO₂ contained in the cooled exhaust gas, thereby obtaining a low CO₂ exhaust gas, wherein the step of reducing the amount of CO₂ comprises;

contacting an aqueous liquid phase with the cooled exhaust gas to cause at least a portion of the CO₂ to dissolve into the aqueous liquid phase and catalyzing the hydration of at least a portion of the dissolved CO₂ and producing a solution containing hydrogen ions and bicarbonate ions; and

wherein said hydration is catalyzed by carbonic anhydrase or an analogue thereof.

37. A process comprising:

cooling an exhaust gas containing CO₂ to produce a cooled exhaust gas, said exhaust gas being derived from combustion for producing heat used to generate steam;

reducing the amount of CO₂ contained in the cooled exhaust gas, thereby obtaining a low CO₂ exhaust gas, wherein the step of reducing the amount of CO₂ comprises;

contacting an aqueous liquid phase with the cooled exhaust gas to cause at least a portion of the CO₂ to dissolve into the aqueous liquid phase and catalyzing the hydration of at least a portion of the dissolved CO₂ and producing a solution containing hydrogen ions and bicarbonate ions; and

wherein said hydration is catalyzed by carbonic anhydrase or an analogue thereof.