Regenerable solvent mixtures for acid-gas separation

Patent metadata

Field	Value
Publication number	US-10065148-B2
Application number	US-201314382108-A
Country	US
Kind code	B2
Filing date	Mar 1, 2013
Priority date	Mar 2, 2012
Publication date	Sep 4, 2018
Grant date	Sep 4, 2018

Abstract

A solvent system for the removal of acid gases from mixed gas streams is provided. Also provided is a process for removing acid gases from mixed gas streams using the disclosed solvent systems. The solvent systems may be utilized within a gas processing system.

First claim

The invention claimed is:

1. A solvent system consisting of an ionic liquid,
wherein the ionic liquid consists of a nucleophilic amine and a protic, non-aqueous liquid;
wherein the ionic liquid reacts with an acidic gas so as to form an ionic solution comprising: 1) a carbamate salt, Zwitterionic sulfamic acid, sulfate salt, or a combination thereof; and 2) a protonated weak acid;
wherein the carbamate salt, Zwitterionic sulfamic acid, sulfate salt, or combination thereof comprises a reaction product between the nucleophilic amine and the acidic gas; and
wherein the protonated weak acid is a protonated form of the protic, non-aqueous liquid.

2. The solvent system of claim 1 , wherein the nucleophilic amine is hydrophobic.

3. The solvent system of claim 1 , wherein the solvent system has a solubility with water of less than about 20 g of solvent per 100 mL of water.

4. The solvent system of claim 1 , wherein the nucleophilic amine is selected from the group consisting of: a primary amine, a secondary amine, a diamine, a triamine, a tetraamine, a pentamine, a cyclic amine, a cyclic diamine, an amine oligomer, a polyamine, an alcoholamine, and mixtures thereof.

5. The solvent system of claim 1 , wherein the protic non-aqueous liquid is a liquid having a pKa of about 8 to about 15.

6. The solvent system of claim 1 , wherein the protic non-aqueous liquid is selected from the group consisting of: a fluorinated alcohol, an optionally substituted phenol; a nitrogen heterocycle, and mixtures thereof.

7. The solvent system of claim 1 , wherein the protic non-aqueous liquid is selected from the group consisting of: 2,2,3,3,4,4,5,5-octafluoropentanol; 2,2,3,3-tetrafluoropropanol; 2,2,3,3,3-pentafluoropropanol; 2,2,3,3,4,4-hexafluorobutanol; 2,2,2-trifluoroethanol; nonafluoro-1-hexanol; 4,4,5,5,6,6,7,7,7-nonafluoroheptanol; 1,1,3,3-hexafluoro-2-phenyl-2-propanol; 4-methoxyphenol; 4-ethoxyphenol; 2-ethoxyphenol; 4-propoxyphenol; imidazole; benzimidazole; N-methyl imidazole; 1-trifluoroacetylimidazole; 1,2,3-triazole; 1,2,4-triazole; 2-trifluoromethylpyrazole; 3,5-bistrifluoromethylpyrazole; 3-trifluoromethylpyrazole, 2-fluorophenol, 3-fluorophenol, 4-fluorophenol, 2-trifluoromethylphenol, 3-trifluoromethylphenol, 4-trifluoromethylphenol, and mixtures thereof.

8. The solvent system of claim 1 , wherein the nucleophilic amine has a pKa of about 8 to about 15.

9. The solvent system of claim 1 , wherein the nucleophilic amine has a pKa of about 8 to about 14.

10. The solvent system of claim 1 , wherein the nucleophilic amine has a pKa of about 8 to about 13.

11. The solvent system of claim 1 , wherein the nucleophilic amine has a pKa of about 8 to about 12.

12. The solvent system of claim 1 , wherein the nucleophilic amine has a pKa of about 8 to about 11.

13. The solvent system of claim 1 , wherein the nucleophilic amine has a pKa of about 8 to about 10.

14. The solvent system of claim 1 , wherein the solvent system has a solubility at 25° C. of less than or equal to about 10 g of solvent per 100 mL of water, such that it tolerates water in a gas stream comprising the acidic gas.

15. The solvent system of claim 1 , wherein the solvent system can tolerate water up to or equal to about 20% water by volume with no degradation of solvent performance.

16. The solvent system of claim 1 , wherein the nucleophilic amine is N-methyl-1-phenylmethanamine, and wherein the protic, non-aqueous liquid is phenol.

Assignees

• Res Triangle Inst

Inventors

• Lail Marty
• Coleman Luke

Classifications

• B01D2258/0283

  Flue gases · CPC title

• B01D53/507

  by treating the gases with other liquids · CPC title

• B01D2257/302

  Sulfur oxides · CPC title

• B01D2252/30

  Ionic liquids and zwitter-ions · CPC title

• B01D2252/205

  Other organic compounds not covered by B01D2252/00 - B01D2252/20494 · CPC title