Aqueous absorbent composition for enhanced removal of hydrogen sulfide from gaseous mixtures and method for using the same

Patent metadata

Field	Value
Publication number	US-2015151240-A1
Application number	US-201314407658-A
Country	US
Kind code	A1
Filing date	Jun 6, 2013
Priority date	Jun 29, 2012
Publication date	Jun 4, 2015
Grant date	—

Abstract

The present invention relates to an aqueous alkanolamine solution for the removal of hydrogen sulfide from gaseous mixtures containing hydrogen sulfide. The aqueous alkanolamine solution comprises (i) an amino compound with the formula: R 1 R 2 NCH 2 CH(OH)CH 2 OH wherein R 1 and R 2 independently represent lower alkyl groups of 1 to 3 carbon atoms, (ii) piperazine, and (iii) optionally a physical solvent, wherein said solution does not contain a strong acid. Further, the present invention relates to a process for removing hydrogen sulfide from a gaseous mixture containing hydrogen sulfide, and additionally other acid gases, if present, for example carbon dioxide, comprising the step of contacting the gaseous mixture contain hydrogen sulfide with the aqueous alkanolamine solution, preferably wherein the temperature of the aqueous alkanolamine solution is equal to or greater than 140° F. Examples of the gaseous mixtures include natural gas, synthesis gas, tail gas, and refinery gas.

First claim

What is claimed is:

1 . An aqueous alkanolamine solution for the removal of acid gasses including hydrogen sulfide from gas mixtures containing hydrogen sulfide comprising:
(i) an amino compound with the formula:
R 1 R 2 NCH 2 CH(OH)CH 2 OH
wherein R 1 and R 2 independently represent methyl, ethyl, propyl, or isopropyl groups, and (ii) piperazine,
wherein said aqueous alkanolamine solution does not contain 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.

2 . The aqueous alkanolamine solution of claim 1 wherein
(i) the amino compound is present in an amount of from 0.1 to 75 weight percent,
and
(ii) the piperazine is present in an amount of from 0.1 to 15 weight percent,

wherein weight percent is based on the total weight of the aqueous alkanolamine solution.

3 . The aqueous alkanolamine solution of claim 1 wherein the amino compound (i) is 3-(dimethylamino)-1,2-propanediol or 3-(diethylamino)-1,2-propanediol.

4 . The aqueous alkanolamine solution of claim 1 further comprises (iii) a physical solvent.

5 . The aqueous alkanolamine solution of claim 4 wherein the physical solvent (iii) is selected from cyclotetramethylenesulfone, dimethyl ethers of polyethylene glycol, 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone, N-formylmorpholine, N-acetylmorpholine, triethylene glycol monomethyl ether, or mixtures thereof.

6 . A process for removing acid gases from a gaseous mixture comprising the step of contacting the gaseous mixture with the aqueous alkanolamine solution of any of the claims 1 to 3 .

7 . The process of claim 6 further comprising the step of steam stripping the aqueous alkanolamine solution such that an acid gas-lean aqueous alkanolamine solution is formed which may be used in said contacting step.

8 . The process of claim 6 wherein the temperature of the aqueous alkanolamine solution is equal to or greater than 140° F.

Assignees

• Dow Global Technologies Llc

Inventors

• Laroche Christophe R
• Padilla Gerardo
• Halnon Timothy D

Classifications

• B01D53/1462 Primary

  Removing mixtures of hydrogen sulfide and carbon dioxide · CPC title

• B01D2252/20489

  with two or more hydroxyl groups · CPC title

• B01D53/1493 Primary

  Selection of liquid materials for use as absorbents · CPC title

• B01D2252/20447

  containing a piperazine-ring · CPC title

• Y02C20/40

  of CO2 · CPC title