Acidic gas removal by aqueous amine solvents

• US 8,816,078 B2
• Filed: 01/11/2011
• Issued: 08/26/2014
• Est. Priority Date: 01/12/2010
• Status: Active Grant

• Current Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Inventors: Rochelle, Gary, Freeman, Stephanie, Chen, Xi, Nguyen, Thu, Voice, Alexander, Rafique, Humera
• Primary Examiner(s): Silverman, Stanley
• Assistant Examiner(s): BERNS, DANIEL J
• Application Number:
  US13/004,606
• Publication Number:
  US 20110171093A1
• Time in Patent Office: 1,323 Days
• Field of Search: 423/228, 544/358
• US Class Current: 544/358
• CPC Class Codes: B01D 2251/80 Organic bases or salts
• CPC Class Codes: B01D 2257/304 Hydrogen sulfide
• CPC Class Codes: B01D 2257/306 Organic sulfur compounds, e.g. mercaptans
• CPC Class Codes: B01D 2257/308 Carbonoxysulfide COS
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 53/1456 Removing acid components
• CPC Class Codes: B01D 53/1493 Selection of liquid materials for use as absorbents

Abstract

Compositions and methods related to the removal of acidic gas. In one embodiment, compositions and methods are provided for the removal of acidic gas from a gas mixture using an aqueous amine solvent comprising water, a first amine, and a second amine, wherein the first amine contributes at least 50% by weight of the solvent'"'"'s total amine concentration.

Claims

1. An aqueous amine solvent comprising water, a first amine, and a second amine, wherein the first amine and the second amine are closely related amines, wherein the first amine is piperazine, and wherein piperazine is present in a concentration of about 2 to 6 molal.

2. The solvent of claim 1 wherein the second amine precipitates solids at rich or lean conditions at a concentration greater than 2 equivalents amine/kg water.

3. The solvent of claim 1 wherein the total amine in the composition is about 30% to 70% by weight.

4. The solvent of claim 1 wherein the second amine is 2-methyl-piperazine, 1-methyl-piperazine, or homopiperazine.

5. The solvent of claim 1 wherein the second amine is 2-methyl-(RS)-piperazine.

6. The solvent of claim 5, further comprising 2,5-dimethyl-piperazine.

7. The solvent of claim 6, wherein piperazine is present in a concentration of 6 molal, 2-methyl-(RS)-piperazine is present in a concentration of 2 molal, and 2,5-dimethyl-piperazine is present in a concentration of less than 1 molal.

8. The solvent of claim 5 wherein 2 methyl-(RS)-piperazine is present in a concentration of about 2 to 6 molal.

9. The solvent of claim 8, wherein piperazine and 2-methyl-(RS)-piperazine are each present in a concentration of 4 molal.

10. The solvent of claim 1 wherein the second amine is 1-methyl-piperazine.

11. The solvent of claim 10 wherein 1 methyl-piperazine is present in a concentration of about 2 to 6 molal.

12. The solvent of claim 10 further comprising dimethyl-piperazine.

13. The solvent of claim 12 wherein the dimethyl-piperazine is 1,4-dimethylpiperazine, 2,5-dimethyl-piperazine, or a combination thereof.

14. An aqueous amine solvent comprising water, a first amine, and a second amine, wherein the first amine and the second amines are closely related amines, wherein the first amine is 2-amino-ethanesulfonic acid, and wherein the first amine contributes at least 50% by weight of the solvent'"'"'s total amine concentration.

15. The solvent of claim 14 wherein the second amine is selected from the group consisting of 3-amino-propanesulfonic acid, 2-amino-isopropyl sulfonic acid, and a combination thereof.

16. An aqueous amine solution comprising water, piperazine, and 1-methyl-piperazine, wherein the solvent'"'"'s total amine concentration is from 8 to 10 molal, and wherein 1-methyl-piperazine is present in a concentration of 1 to 4 molal.

17. An aqueous amine solvent comprising water, piperazine, and 2-methyl-(RS)-piperazine, wherein piperazine is present in a concentration of about 5 to 8 molal, and wherein 2-methyl-(RS)-piperazine is present in a concentration of about 1 to 3 molal.

18. An aqueous amine solvent comprising water, piperazine, and 1-methyl-piperazine, wherein piperazine is present in a concentration of about 5 to 8 molal, and wherein 1-methyl-piperazine is present in a concentration of about 1 to 3 molal.