GAS PURIFICATION SYSTEM HAVING PROVISIONS FOR CO2 INJECTION OF WASH WATER

• US 20090282977A1
• Filed: 05/06/2009
• Published: 11/19/2009
• Est. Priority Date: 05/14/2008
• Status: Abandoned Application

• Current Assignee: Alstom Technology Ltd. (Alstom SA)
• Original Assignee: Alstom Technology Ltd. (Alstom SA)
• Inventors: Koss, Peter Ulrich
• Application Number:
  US12/436,309
• Publication Number:
  US 20090282977A1
• Time in Patent Office: Days
• US Class Current: 95/199
• CPC Class Codes: B01D 2257/40 Nitrogen compounds
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 53/1406 Multiple stage absorption
• CPC Class Codes: B01D 53/1493 Selection of liquid materials for use as absorbents
• CPC Class Codes: B01D 53/42 Basic components B01D53/44 takes precedence
• CPC Class Codes: B01D 53/58 Ammonia
• CPC Class Codes: C01C 1/26 Carbonates or bicarbonates of ammonium
• CPC Class Codes: Y02C 20/40 of CO2
• CPC Class Codes: Y02P 20/151 Reduction of greenhouse gas [GHG] emissions, e.g. CO2

Abstract

The present invention relates to a methods and systems for the removal of contaminants from a gas stream, comprising the steps of: a)introducing CO₂ into a wash water stream to obtain a CO₂ enriched wash water; and b) contacting said CO₂ enriched wash water with the gas stream containing contaminants to be removed to allow absorption of the contaminants into the CO₂ enriched wash water. The present invention further relates to the use of CO₂ enriched wash water for removal of alkaline contaminants from a gas stream in a gas purification system.

Claims

1. A method for the removal of contaminants from a gas stream, comprising the steps of:

a) introducing CO₂ into a wash water stream to obtain a CO₂ enriched wash water; and

b) contacting said CO₂ enriched wash water with the gas stream containing contaminants to be removed to allow absorption of the contaminants into the CO₂ enriched wash water.

2. A method according to claim 1, wherein at least one of the contaminants is an alkaline compound.

3. A method according to claim 2, wherein at least one of the contaminants is selected from the group consisting of ammonia and amine compounds, preferably ammonia.

4. A method according to claim 1, wherein the CO₂ enriched wash water comprises 0.01-5 wt % of CO₂, preferably 0.01-2 wt % of CO₂, preferably 0.01-1 wt % of CO₂.

5. A method according to claim 1, wherein the CO₂ introduced into the wash water stream in step a) is in liquid form.

6. A method according to claim 1, wherein step b) is performed in a countercurrent flow mode.

7. A method according to claim 1, wherein step b) is performed in a packed bed column.

8. A method according to claim 1, wherein the CO₂ introduced into the wash water stream in step a) is obtained from a process for removal of CO₂ from a gas stream.

9. A method according to claim 8, wherein said process for removal of CO₂ from a gas stream comprises the step of scrubbing said gas stream with a liquid comprising ammonia or an amine compound, preferably ammonia.

10. A method according to claim 1, wherein in step b) the gas stream containing contaminants to be removed is a product resulting from a process for removal of CO₂, and the CO₂ introduced into the wash water stream in step a) is obtained from said process for removal of CO₂.

21. A method according to claim 1, wherein at least one of the contaminants is an alkaline compound.

22. A method according to claim 2, wherein at least one of the contaminants is selected from the group consisting of ammonia and amine compounds, preferably ammonia.

23. A method according to claim 1, wherein the CO₂ enriched wash water comprises 0.01-5 wt % of CO₂, preferably 0.01-2 wt % of CO₂, preferably 0.01-1 wt % of CO₂.

24. A method according to claim 1, wherein the CO₂ introduced into the wash water stream in step a) is in liquid form.

25. A method according to claim 1, wherein step b) is performed in a countercurrent flow mode.

26. A method according to claim 1, wherein step b) is performed in a packed bed column.

11. A method for the removal of contaminants from a gas stream, comprising the steps of:

a) removing CO₂ from a CO₂ rich gas stream to obtain a CO₂ lean gas stream;

b) introducing CO₂ removed from said CO₂ rich gas stream in step a) into a wash water stream to obtain a CO₂ enriched wash water; and

c) contacting said CO₂ enriched wash water with the CO₂ lean gas stream obtained in step a) to allow absorption of contaminants in the CO₂ lean gas stream into the CO₂ enriched wash water.

12. (canceled)

13. A gas purification system comprising a first contactor device arranged for receiving a gas stream and contacting it with a wash water stream, characterized in that said system comprises means for introducing CO₂ into said wash water stream upstream of said contactor device.

14. A gas purification system according to claim 13, wherein said means for introducing CO₂ is adapted for introducing the CO₂ in liquid form.

15. A gas purification system according to claim 13, further comprising a second contactor device arranged for receiving a CO₂ rich gas stream and contacting it with a liquid comprising ammonia or an amine compound to produce a CO₂ lean gas stream, wherein said first contactor device is arranged for receiving said CO₂ lean gas stream and contacting it with a wash water stream, characterized in that said system comprises means for introducing CO₂ into said wash water stream upstream of said first contactor device.

16. (canceled)

17. (canceled)

18. (canceled)

19. (canceled)

20. (canceled)