METHOD FOR REMOVAL OF CARBON DIOXIDE FROM A PROCESS GAS

• US 20110064636A1
• Filed: 09/15/2009
• Published: 03/17/2011
• Est. Priority Date: 09/15/2009
• Status: Active Grant

• Current Assignee: General Electric Technology GmbH (General Electric Company)
• Original Assignee: Alstom Technology Ltd. (Alstom SA)
• Inventors: Petig, Arlyn V., Kozak, Frederic Z.
• Granted Patent: US 8,790,605 B2
• Time in Patent Office: Days
• US Class Current: 423/234
• CPC Class Codes: B01D 2252/102 Ammonia
• CPC Class Codes: B01D 53/1406 Multiple stage absorption
• CPC Class Codes: B01D 53/1425 Regeneration of liquid absorbents
• CPC Class Codes: B01D 53/1475 Removing carbon dioxide
• 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

Abstract

The invention relates to a method of removing carbon dioxide from a process gas, the method comprising: a) allowing an ammoniated solution to enter an absorption arrangement, said absorption arrangement comprising at least a first absorber; b) contacting the ammoniated solution with the process gas in said first absorber, the ammoniated solution capturing at least a part of the carbon dioxide of the process gas; c) allowing the ammoniated solution to exit the absorption arrangement; d) cooling the ammoniated solution, wherein at least a part of the captured carbon dioxide is precipitated as solid salt; e) allowing the cooled ammoniated solution to enter a separator, in which separator at least a part of the precipitated solids are removed from the ammoniated solution, after which the ammoniated solution is allowed to exit the separator; f) heating the ammoniated solution; and g) allowing the heated ammoniated solution to re-enter the absorption arrangement. The invention also relates to a carbon dioxide removal system.

Claims

1. A method of removing carbon dioxide from a process gas, the method comprising:

a) allowing an ammoniated solution to enter an absorption arrangement, said absorption arrangement comprising at least a first absorber;

b) contacting the ammoniated solution with the process gas in said first absorber, the ammoniated solution capturing at least a part of the carbon dioxide of the process gas;

c) allowing the ammoniated solution to exit the absorption arrangement;

d) cooling the ammoniated solution, wherein at least a part of the captured carbon dioxide is precipitated as solid salt;

e) allowing the cooled ammoniated solution to enter a separator, in which separator at least a part of the precipitated solids are removed from the ammoniated solution, after which the ammoniated solution is allowed to exit the separator;

f) heating the ammoniated solution; and

g) allowing the heated ammoniated solution to re-enter the absorption arrangement.

2. The method of claim 1, wherein the temperature of the ammoniated solution in b) is between about 10°

C. and 20°

C. (50°

F. and 68°

F.).

3. The method of claim 2, wherein the temperature of the ammoniated solution in b) is about 15°

C. (59°

F.).

4. The method of claim 1, wherein the ammoniated solution is in d) cooled to between about 0°

C. and 10°

C. (32°

F. and 50°

F.).

5. The method of claim 4, wherein the ammoniated solution is in d) cooled to about 5°

C. (41°

F.).

6. The method of claim 1, wherein the ammoniated solution is in f) heated to at least 7°

C. (45°

F.).

7. The method of claim 6, wherein the ammoniated solution is in f) heated to between about 7°

C. and 15°

C. (45°

F. and 59°

C.).

8. The method of claim 7, wherein the ammoniated solution is in f) heated to between about 7°

C. and 10°

C. (45°

F. and 50°

C.).

9. The method of claim 1, wherein the cooling of d) and the heating of f) is at least partly achieved by means of a heat exchanger, in which heat exchanger the ammoniated solution exiting the absorption arrangement in c) is the heating medium and the ammoniated solution exiting the separator in e) is the cooling medium.

10. The method of claim 1, wherein the cooling of d) is at least partly achieved by means of a heat exchanger, in which heat exchanger cold water is used as a cooling medium.

11. The method of claim 1, wherein the separator is a hydrocyclone.

12. The method of claim 1, wherein some liquid solution is also removed together with the solids in the separator, forming a leaving suspension or slurry, which suspension or slurry has a solids content of between about 10% and 20% by weight of the suspension or slurry.

13. The method of claim 1, further comprising:

h) contacting the heated ammoniated solution with the process gas in a second absorber of the absorption arrangement, the second absorber being separate from the first absorber, the ammoniated solution absorbing and solving at least a part of the carbon dioxide of the process gas in the second absorber.

14. A carbon dioxide removal system for removing carbon dioxide from a process gas, the system comprising:

an absorption arrangement, said absorption arrangement comprising at least a first absorber, said first absorber being arranged to, inside said first absorber, allow contact between the process gas and an ammoniated solution such that at least a part of the carbon dioxide of the process gas is captured by the ammoniated solution;

a first heat exchanger arranged to cool the ammoniated solution including captured carbon dioxide after it has exited the absorption arrangement;

a separator arranged to remove at least a part of any solids in the cooled ammoniated solution;

a second heat exchanger arranged to heat the ammoniated solution after it has exited the separator; and

piping connecting, and arranged to allow a flow of the ammoniated solution between, the absorption arrangement and the first heat exchanger, the first heat exchanger and the separator, the separator and the second heat exchanger, as well as the second heat exchanger and the absorption arrangement.

15. The system of claim 14, wherein the first and second heat exchangers are arranged to cooperate with each other such that the ammoniated solution being cooled in the first heat exchanger is at least partly cooled by the ammoniated solution being heated in the second heat exchanger as cooling medium, and the ammoniated solution being heated in the second heat exchanger is at least partly heated by the ammoniated solution being cooled in the first heat exchanger as heating medium.