System and method for recovering ammonia from a chilled ammonia process

• US 8,986,640 B1
• Filed: 01/07/2014
• Issued: 03/24/2015
• Est. Priority Date: 01/07/2014
• Status: Active Grant

• Current Assignee: General Electric Technology GmbH (GE Aerospace)
• Original Assignee: Alstom Technology Ltd. (Alstom SA)
• Inventors: Dube, Sanjay Kumar
• Primary Examiner(s): VANOY, TIMOTHY C
• Application Number:
  US14/149,315
• Time in Patent Office: 441 Days
• Field of Search: 423/237, 423/238
• US Class Current: 423/237
• CPC Class Codes: B01D 2252/102 Ammonia
• CPC Class Codes: B01D 53/1425 Regeneration of liquid absorbents
• CPC Class Codes: B01D 53/1475 Removing carbon dioxide
• CPC Class Codes: B01D 53/62 Carbon oxides
• CPC Class Codes: Y02C 20/40 of CO2

Abstract

An ammonia recovery system and method for removing ammonia from a gas stream is provided. The system includes an ammonia recovery vessel for contacting a solution, having a dissolved acidic salt, with the gas stream, having ammonia. The dissolved acidic salt solution absorbs the ammonia in the gas stream to provide an ammonia-lean gas stream and an ammonia-rich solution. The ammonia-rich solution is heated within an ammonia stripper to release the ammonia from the ammonia-rich solution to thereby generate an ammonia-rich gas stream and the solution having dissolved acidic salt. A heat exchanger heats the dissolved acidic salt from the ammonia stripper prior to the solution being provided to the ammonia recovery system. The acidic salt has a low thermal decomposition.

Claims

1. An ammonia recovery system for removing ammonia from a gas stream, the system comprising:

an ammonia recovery vessel for contacting a solution having a dissolved acidic salt with the gas stream having ammonia wherein the dissolved acidic salt solution absorbs the ammonia in the gas stream to provide ammonia-lean gas stream and an ammonia-rich solution;

an ammonia stripper including a vessel that receives and heats the ammonia-rich solution from the vessel to release the ammonia from the ammonia-rich solution to generate an ammonia rich gas stream comprising ammonia and water, and the solution having dissolved acidic salt;

a heat exchanger for receiving the dissolved acidic salt solution from the ammonia stripper and heating the solution prior the solution being provided to the ammonia recovery vessel;

wherein the acidic salt has a low thermal decomposition temperature.

2. The ammonia recovery system of claim 1, further includes a second heat exchanger for heating the ammonia-rich solution prior to entering the ammonia stripper.

3. The ammonia recovery system of claim 1, further includes a second heat exchanger that exchanges heat from the ammonia-lean solution from the ammonia stripper with the ammonia-rich solution provided to the ammonia stripper.

4. The ammonia recovery system of claim 1, wherein the acidic salt has a thermal decomposition temperature between 50 and 300 degrees Celsius.

5. The ammonia recovery system of claim 1, wherein the acidic salt includes at least one of ammonium acetate and ammonium phosphate.

6. The ammonia recovery system of claim 1, further includes a carbon capture system having an absorption vessel that contacts the gas stream with a chilled solution having ammonia to absorb CO₂ from the flue gas stream to generate a CO₂ rich solution and the gas stream having ammonia.

7. The ammonia recovery system of claim 1, wherein the gas stream is a flue gas stream from a combustion process.

8. The ammonia recovery system of claim 6, further includes a regeneration vessel for receiving the CO₂ rich solution and heating the solution to provide a CO₂ rich gas stream and a CO₂ lean absorption solution which is recycled back to the absorber vessel.

9. The ammonia recovery system of claim 1, further comprising a direct contact cooling vessel for cooling the gas stream prior to entering the absorption vessel.

10. The ammonia recovery system of claim 9, further comprising a pipe to provide the water from the direct contact cooling vessel to the second heat exchanger to preheat the ammonia-lean solution from the ammonia stripper prior to entering the ammonia recovery vessel.

11. A method of removing ammonia from a gas stream, the method comprising:

contacting within a first vessel a solution having a dissolved acidic salt with the gas stream having ammonia wherein the dissolved acidic salt solution absorbs the ammonia in the gas stream to provide ammonia-lean gas stream and an ammonia-rich solution;

heating within a second vessel the ammonia-rich solution to release the ammonia from the ammonia-rich solution to generate an ammonia rich gas stream comprising ammonia and water, and a solution having dissolved acidic salt;

heating the dissolved acidic salt solution;

providing the heated dissolved acidic salt solution back to the first vessel;

wherein the acidic salt has a low thermal decomposition temperature.

12. The method of claim 11, further comprising heating the ammonia-rich solution prior to entering the second vessel.

13. The method of claim 11, further comprising exchanging heat from the ammonia-lean solution from the second vessel with the ammonia-rich solution provided to the second vessel.

14. The method of claim 11, wherein the acidic salt has a thermal decomposition temperature between 50 and 300 degrees Celsius.

15. The method of claim 11, wherein the acidic salt includes at least one of ammonium acetate and ammonium phosphate.

16. The method of claim 11, further comprising contacting in a third vessel the gas stream with a chilled solution having ammonia to absorb CO₂ from the flue gas stream to generate a CO₂ rich solution and the gas stream having ammonia.

17. The method of claim 11, wherein the gas stream is a flue gas stream from a combustion process.

18. The method of claim 16, further comprising heating the CO₂ rich solution to provide a CO₂ rich gas stream and a CO₂ lean absorption solution which is recycled back to the third vessel.

19. The method of claim 16, further comprising cooling in a fourth vessel the gas stream prior to entering the third vessel.

20. The method of claim 19, further comprising providing water from the fourth vessel to preheat the ammonia-lean solution from the second vessel prior to entering the first vessel.