Process for the removal of acid gases from gaseous mixtures using an aqueous solution of 2-dimethylamino-2-hydroxymethyl-1, 3-propanediol

Patent metadata

Field	Value
Publication number	US-10286356-B2
Application number	US-201515502701-A
Country	US
Kind code	B2
Filing date	Oct 6, 2015
Priority date	Oct 10, 2014
Publication date	May 14, 2019
Grant date	May 14, 2019

Abstract

The present invention relates to an aqueous alkanolamine solution demonstrating low volatility comprising 2-di-methylamino-2-hydroxymethyl-1, 3-propanediol useful for removing acid gases from gaseous mixtures. Said aqueous alkanolamine solution may further comprise one or more of an acid or acid-forming compound, another amino compound, an activator, a physical solvent, or one or more other compounds used in gal-liquid treatment practices. Further, the present invention relates to a process for removing acid gases from a gaseous mixture, preferably hydrogen sulfide, comprising the step of contacting the gaseous mixture with said aqueous alkanolamine solution. Examples of the gaseous mixtures include natural gas, synthesis gas, tail gas, and refinery gas.

First claim

What is claimed is:

1. A process for removing acid gases from a gaseous mixture, the process comprising the step of contacting the gaseous mixture with an aqueous alkanolamine solution, wherein the alkanolamine solution consists essentially of:
(i) 2-dimethylamino-2-hydroxymethyl-1,3-propanediol,
(ii) an acid having a pKa of 8 or less or an acid-forming material capable of forming in aqueous medium an acid having a pKa of 8 or less,
(iii) an additional amino compound, and
(iv) water.

2. The process of claim 1 wherein the temperature of the aqueous alkanolamine solution is equal to or greater than 40° F.

3. The process of claim 1 or 2 further comprising the step of partially removing acid gases from the aqueous alkanolamine solution to form an acid gas lean aqueous alkanolamine solution which may be used in said contacting step.

4. The process of claim 3 wherein the step of partially removing acid gases is achieved by steam stripping.

5. The process of claim 1 wherein based on the total weight of the aqueous alkanolamine solution:
(i) the 2-dimethylamino-2-hydroxymethyl-1, 3-propanediol is present in an amount of from 0.1 to 75 weight percent,
(ii) the acid or acid-forming material is present in an amount of from 0.1 to 25 weight percent, and
(iii) the additional amino compound is present in an amount of from 0.1 to 75 weight percent.

6. The process of claim 1 wherein the acid or acid-forming material (ii) is present in an amount of 0.1 to 25 weight percent and is phosphoric acid, sulfuric acid, boric acid, formic acid, or hydrochloric acid.

7. The process of claim 1 wherein the additional amino compound (iii) is present in an amount of 0.1 to 75 weight percent and is monoethanolamine (MEA); tris(2-hydroxyethyl)amine (TEA); tris(2-hydroxypropyl)amine (triisopropanol); tributanolamine; bis(2-hydroxyethyl)methylamine (MDEA); 2-diethylaminoethanol (DEEA); 2-dimethylaminoethanol (DMEA); 3-dimethylamino-1-propanol; 3-diethylamino-1-propanol; 2-diisopropylaminoethanol (DIEA); N,N-bis(2-hydroxypropyl)methylamine (MDIPA); N,N′-bis(2-hydroxyethyl)piperazine (DiHEP); diethanolamine (DEA); 2-(tert-butylamino)ethanol; 2-(tert-butylaminoethoxy)ethanol; 2-amino-2-methylpropanol (AMP); 2-(2-amino-ethoxy)ethanol; or a 1-hydroxyethyl-4-pyridinylpiperazine compound.

8. A process for removing acid gases from a gaseous mixture, the process comprising the step of contacting the gaseous mixture with an aqueous alkanolamine solution, wherein the aqueous alkanolamine solution consists essentially of:
(i) 2-dimethylamino-2-hydroxymethyl-1,3-propanediol,
(ii) an acid having a pKa of 8 or less or an acid-forming material capable of forming in aqueous medium an acid having a pKa of 8 or less, and
(iii) water.

9. The process of claim 8 wherein the acid or acid-forming material (ii) is present in an amount of 0.1 to 25 weight percent and is phosphoric acid, sulfuric acid, boric acid, formic acid, or hydrochloric acid.

10. The process of claim 8 further comprising the step of partially removing acid gases from the aqueous alkanolamine solution to form an acid gas lean aqueous alkanolamine solution which may be used in said contacting step.

11. The process of claim 10 wherein the step of partially removing acid gases is achieved by steam stripping.

12. The process of claim 8 wherein hydrogen sulfide is selectively removed from a gaseous mixture comprising hydrogen sulfide wherein the aqueous alkanolamine solution does not comprise any additional amino compounds.

13. The process of claim 12 wherein the acid or acid-forming material (ii) is present in an amount of 0.1 to 25 weight percent and is phosphoric acid, sulfuric acid, boric acid, formic acid, or hydrochloric acid.

Assignees

• Dow Global Technologies Llc

Inventors

• Laroche Christophe R
• Dowdle John R

Classifications

• C10K1/003

  of acid contaminants, e.g. acid gas removal · CPC title

• C10K1/143

  containing amino groups · CPC title

• B01D53/1493 Primary

  Selection of liquid materials for use as absorbents · CPC title

• C10K1/004

  Sulfur containing contaminants, e.g. hydrogen sulfide · CPC title

• B01D53/1468

  Removing hydrogen sulfide · CPC title