Absorbent for selective removal of hydrogen sulfide from a fluid stream

Patent metadata

Field	Value
Publication number	US-10464013-B2
Application number	US-201515506451-A
Country	US
Kind code	B2
Filing date	Aug 20, 2015
Priority date	Aug 25, 2014
Publication date	Nov 5, 2019
Grant date	Nov 5, 2019

Abstract

An absorbent for selective removal of hydrogen sulfide from a fluid stream comprises an aqueous solution of a) a tertiary amine, b) a sterically hindered secondary amine of the general formula (I)

in which R 1 and R 2 are each independently selected from C 1-4 -alkyl and C 1-4 -hydroxyalkyl; R 3 , R 4 , R 5 and R 6 are each independently selected from hydrogen, C 1-4 -alkyl and C 1-4 -hydroxyalkyl, with the proviso that at least one R 4 and/or R 5 radical on the carbon atom bonded directly to the nitrogen atom is C 1-4 -alkyl or C 1-4 -hydroxyalkyl when R 3 is hydrogen; x and y are integers from 2 to 4 and z is an integer from 1 to 4; where the molar ratio of b) to a) is in the range from 0.05 to 1.0, and c) an acid in an amount, calculated as neutralization equivalent relative to the protonatable nitrogen atoms in a) and b), of 0.05 to 15.0%. One preferred amine of the formula I is 2-(2-tert-butylaminoethoxy)ethanol. The absorbent allows a defined H 2 S selectivity to be set at pressures of the kind typical in natural gas processing.

First claim

The invention claimed is:

1. A process for removing an acidic gas from a fluid stream, said process comprising:
contacting the fluid stream which is selected from gases and which has a total pressure of at least 3.0 bar, with an absorbent, comprising an aqueous solution comprising:
a) a tertiary amine;
b) a sterically hindered secondary amine of the general formula (I)

in which R 1 and R 2 are each independently selected from C 1-4 -alkyl and C 1-4 -hydroxyalkyl; R 3 , R 4 , R 5 and R 6 are each independently selected from hydrogen, C 1-4 -alkyl and C 1-4 -hydroxyalkyl, with the proviso that at least one R 4 and/or R 5 radical on the carbon atom bonded directly to the nitrogen atom is C 1-4 -alkyl or C 1-4 -hydroxyalkyl when R 3 is hydrogen; x and y are integers from 2 to 4 and z is an integer from 1 to 4; where the molar ratio of b) to a) is in the range from 0.3 to 0.7, and
c) an acid in an amount, calculated as neutralization equivalent relative to the protonatable nitrogen atoms in a) and h), of 1.0 to 9.0%;
wherein
the acid is selected from the group consisting of a mineral acid (excluding phosphoric acid and partial esters thereof), a carboxylic acid, a sulfonic acid, a tertiary aminocarboxylic acid, an N-sec-alkylaminocarboxylic acid and an N-tert-alkylamino-carboxylic acid, with the proviso that the acid does not comprise a phosphonic acid, and there is
a partial hydrogen sulfide pressure of at least 0.1 bar and/or a partial carbon dioxide pressure of at least 0.2 bar in the fluid stream.

2. The process according to claim 1 , wherein the fluid stream comprises a hydrocarbon.

3. The process according to claim 1 , wherein there is a partial hydrogen sulfide pressure of at least 0.1 bar and a partial carbon dioxide pressure of at least 1.0 bar in the fluid stream.

4. The process according to claim 1 , wherein the laden absorbent is regenerated by
a) heating,
b) decompression,
c) stripping with an inert fluid
or a combination of two or all of these measures.

Assignees

• Basf Se

Inventors

• Vorberg Gerald
• Notz Ralf
• Ingram Thomas
• Sieder Georg
• Katz Torsten

Classifications

• C10L2290/545

  Washing, scrubbing, stripping, scavenging for separating fractions, components or impurities during preparation or upgrading of a fuel · CPC title

• C10L2290/48

  Expanders, e.g. throttles or flash tanks · CPC title

• C10L2290/06

  Heat exchange, direct or indirect · CPC title

• C10L2200/0268

  Phosphor containing compounds · CPC title

• C10L2200/0263

  Sulphur containing compounds · CPC title