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-9937462-B2
Application number	US-201615196541-A
Country	US
Kind code	B2
Filing date	Sep 15, 2016
Priority date	Jun 29, 2012
Publication date	Apr 10, 2018
Grant date	Apr 10, 2018

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. A process for removing hydrogen sulfide from a gaseous mixture comprising hydrogen sulfide consisting of the step(s) of:
A) contacting the gaseous mixture with an aqueous alkanolamine solution, providing a hydrogen sulfide-loaded aqueous alkanolamine solution and a cleaned gas, wherein the aqueous alkanolamine solution consists of:
(i) 3-(dimethylamino)-1,2-propanediol,
(ii) piperazine,
and
(iii) optionally a physical solvent selected from cyclotetramethylenesulfone, dimethyl ethers of polyethylene glycol, 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone, N-formylmorpholine, N-acetylmorpholine, or mixtures thereof,
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,

B) optionally, steam stripping the hydrogen sulfide-loaded aqueous alkanolamine solution, providing an acid gas-lean aqueous alkanolamine solution,
and
C) optionally, contacting the gaseous mixture in step A) with the acid gas-lean aqueous alkanolamine solution from step B).

2. The process of claim 1 wherein
(i) the 3-(dimethylamino)-1,2-propanediol is present in an amount from 0.1 to 75 weight percent,
and
(ii) the piperazine is present in an amount from 0.1 to 15 weight percent,
wherein weight percent is based on the total weight of the aqueous alkanolamine solution.

3. The process of claim 1 wherein the physical solvent is present in an amount from 1 to 75 weight percent based on the total weight of the aqueous alkanolamine solution.

4. The process of claim 1 wherein the temperature of the aqueous alkanolamine solution in step A) is equal to or greater than 140° F.

Assignees

• Dow Global Technologies Llc

Inventors

• Laroche Christophe R
• Padilla Gerardo
• Halnon Timothy D

Classifications

• B01D2252/20421

  Primary amines · CPC title

• B01D2252/2025

  Ethers or esters of alkylene glycols, e.g. ethylene or propylene carbonate · CPC title

• B01D2252/103

  Water · CPC title

• B01D2252/20431

  Tertiary amines · CPC title

• C10K1/003

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