ACIDIC GAS REMOVAL BY AQUEOUS AMINE SOLVENTS

• US 20110171093A1
• Filed: 01/11/2011
• Published: 07/14/2011
• 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: Chen, Xi, Nguyen, Thu, Freeman, Stephanie, Voice, Alexander, Rafique, Humera, Rochelle, Gary
• Granted Patent: US 8,816,078 B2
• Time in Patent Office: Days
• US Class Current: 423/228
• 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 contributes at least 50% by weight of the solvent'"'"'s total amine concentration.

2. The solvent of claim 1 wherein the second amine contributes less than 50% by weight of the solvent'"'"'s total amine concentration.

3. The solvent of claim 1 wherein the first amine is piperazine.

4. The solvent of claim 1 wherein the first amine and the second amine differ from each other by one or more of:

addition or removal of one methyl group or addition or removal of one methylene group;

cis or trans isomers;

rearrangement of one methyl group or rearrangement of one methylene group;

or right or left-handed orientation.

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

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

7. The solvent of claim 5 wherein the piperazine is present in a concentration of about 5 to 8 molal and the 2-methyl-(RS)-piperazine is present in a concentration of about 1 to 3 molal.

8. The solvent of claim 1 wherein the first amine is piperazine and the second amine is 1-methyl-piperazine.

9. The solvent of claim 8 wherein the piperazine and the 1-methyl-piperazine are present in a concentration of about 2 to 6 molal.

10. The solvent of claim 8 wherein the piperazine is present in a concentration of about 5 to 8 molal and the 1-methyl-piperazine is present in a concentration of about 1 to 3 molal.

11. The solvent of claim 1 wherein the first amine is piperazine and the second amine is 1-methyl-piperazine, and further comprising dimethyl-piperazine.

12. The solvent of claim 11 wherein the dimethyl-piperazine is 1,4-dimethyl-piperazine, 2,5-dimethyl-piperazine, or a combination thereof.

13. The solvent of claim 1 wherein the first amine is piperazine and the second amine is hexamethylenediamine.

14. The solvent of claim 1 wherein the first amine is an amino acid, wherein the amino acid is 2-amino-ethanesulfonic acid.

15. The solvent of claim 1 wherein the first amine is 2-amino-ethanesulfonic acid and the second amine is selected from the group consisting of 3-amino-propanesulfonic acid, 2-amino-isopropyl sulfonic acid, and a combination thereof.

16. The solvent of claim 1 wherein at least one of the amines precipitates solids at rich or lean conditions when used at a concentration greater than 2 equivalents amine/kg water.

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

18. A method comprising contacting an acidic gas with an aqueous amine solvent, wherein the aqueous amine solvent comprises 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.

19. The method of claim 18 wherein the acidic gas comprises at least one selected from the group consisting of CO₂, H₂S, COS, CS₂, and mercaptans.

20. The method of claim 18 wherein the aqueous amine solvent comprises piperazine and 2-methyl-(RS)-piperazine.

21. The method of claim 18 wherein the aqueous amine solvent comprises piperazine, 1-methyl-piperazine, and dimethyl-piperazine.