Absorbent for the selective removal of hydrogen sulfide

Patent metadata

Field	Value
Publication number	US-10617993-B2
Application number	US-201615763604-A
Country	US
Kind code	B2
Filing date	Sep 28, 2016
Priority date	Sep 29, 2015
Publication date	Apr 14, 2020
Grant date	Apr 14, 2020

Abstract

An absorbent for selective removal of hydrogen sulfide from a fluid stream comprises an aqueous solution comprising a) a tertiary amine; b) an aminic pH promoter selected from the compounds mentioned in the description; where the molar ratio of b) to a) is in the range from 0.05 to 1.0; and c) an acid having a pKA of less than 6 in such an amount that the pH of the aqueous solution measured at 120° C. is 7.9 to less than 8.8. Also described is a process for removing acidic gases from a fluid stream, in which the fluid stream is contacted with the absorbent. The absorbent is notable for a low regeneration energy.

First claim

The invention claimed is:

1. An absorbent for selective removal of hydrogen sulfide over carbon dioxide from a fluid stream, the absorbent comprising an aqueous solution comprising:
a) a tertiary amine of the general formula (I)

in which R 1 is a C 2-4 -hydroxyalkyl and R 2 and R 3 are each independently selected from C 1-3 -alkyl and C 2-4 -hydroxyalkyl;
b) an aminic pH promoter, the aminic pH promoter being selected from the group consisting of:
compounds of the general formula (II):

in which
R 4 is selected from the group consisting of hydrogen; OR 7 in which R 7 is selected from the group consisting of hydrogen and C 1-4 -alkyl; and NR 8 R 9 in which R 8 and R 9 are each independently selected from the group consisting of C 1-5 -alkyl and C 2-5 -hydroxyalkyl or R 8 is hydrogen and R 9 is selected from the group consisting of C 1-5 -alkyl and C 2-5 -hydroxyalkyl;
R 5 and R 6 are each independently selected from the group consisting of C 1-5 -alkyl and C 2-5 -hydroxyalkyl or R 5 is hydrogen and R 6 is selected from the group consisting of C 1-5 -alkyl and C 2-5 -hydroxyalkyl; and

compounds of the general formula (III):

in which
R 10 , R 11 , R 12 and R 13 are each independently selected from the group consisting of C 1-5 -alkyl, C 1-5 -aminoalkyl, C 2-5 -hydroxyalkyl and (di-C 1-4 -alkylamino)-C 1-5 -alkyl; and
x is an integer from 2 to 4; and

c) an acid having a pK A of less than 6 in such an amount that a pH of the aqueous solution measured at 120° C. is 7.9 to less than 8.8,
wherein a molar ratio of b) to a) is in the range from 0.05 to 1.

2. The absorbent according to claim 1 , wherein the total concentration of a) and b) in the aqueous solution is 10% to 60% by weight.

3. The absorbent according to claim 1 , wherein the tertiary amine a) is methyldiethanolamine.

4. The absorbent according to claim 1 , wherein the molar ratio of b) to a) ranges from 0.1 to 0.9.

5. The absorbent according to claim 1 , wherein the acid is an acid having a pK A of less than 5.

6. The absorbent according to claim 1 , wherein the acid is an inorganic acid.

7. A process for selectively removing hydrogen sulfide over carbon dioxide from a fluid stream, the process comprising contacting the fluid stream with the absorbent according to claim 1 .

8. The process according to claim 7 , wherein the fluid stream comprises hydrocarbons.

9. The process according to claim 7 , wherein there is a partial hydrogen sulfide pressure of at least 0.1 bar and a partial carbon dioxide pressure of at least 0.2 bar in the fluid stream.

10. The process according to claim 7 , wherein the fluid stream has a total pressure of at least 3.0 bar.

11. The process according to claim 7 , further comprising regenerating laden absorbent 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
• Gruenanger Christian
• Deglmann Peter

Classifications

• B01D2252/20405

  Monoamines · CPC title

• B01D53/1468

  Removing hydrogen sulfide · CPC title

• B01D2252/2041

  Diamines · CPC title

• B01D2252/602

  Activators, promoting agents, catalytic agents or enzymes · CPC title

• B01D2252/20426

  Secondary amines · CPC title