Cyclic amine for selectively removing hydrogen sulphide

Patent metadata

Field	Value
Publication number	US-11130094-B2
Application number	US-201916594526-A
Country	US
Kind code	B2
Filing date	Oct 7, 2019
Priority date	Sep 29, 2015
Publication date	Sep 28, 2021
Grant date	Sep 28, 2021

Abstract

The use of an amine of the formula (I)

in which the R 1 to R 5 radicals are each as defined in the description, and an absorbent and a process for removing acidic gases from a fluid stream, especially for selectively removing hydrogen sulfide over carbon dioxide. The invention also relates to particular amines suitable for selective removal of hydrogen sulfide. Absorbents based on amines of the formula (I) have high selectivity, high loading capacity and good regeneration capacity.

First claim

The invention claimed is:

1. A process for selectively removing hydrogen sulfide from a fluid stream comprising carbon dioxide and hydrogen sulfide, the process comprising contacting the fluid stream with an absorbent comprising an amine of formula (I):

wherein
R 1 , R 2 , R 3 and R 4 are independently selected from C 1 -C 5 -alkyl and C 2 -C 5 -hydroxyalkyl;
R 5 is NR 6 R 7 ; and
R 6 is selected from hydrogen, C 1 -C 5 -alkyl and C 2 -C 5 -hydroxyalkyl and R 7 is selected from C 1 -C 5 -alkyl and C 2 -C 5 -hydroxyalkyl, with the proviso that, when R 6 is hydrogen, R 7 is C 3 -C 5 -alkyl bonded to the nitrogen atom via a secondary or tertiary carbon atom;
to obtain a treated fluid stream and a laden absorbent,
wherein the following expression is satisfied:
(mol(H 2 S)/(mol(CO 2 ) in the liquid phase/(mol(H 2 S)/(mol(CO 2 )) in the gas phase≥1.

2. The process according to claim 1 , in which R 1 , R 2 , R 3 and R 4 are methyl.

3. The process according to claim 1 , wherein the absorbent is an aqueous solution.

4. The process according to claim 1 , wherein the absorbent comprises at least one organic solvent.

5. The process according to claim 1 , wherein the absorbent comprises an acid having a pK A of less than 6.

6. The process according to claim 1 , wherein the absorbent comprises a tertiary amine or highly sterically hindered amine.

7. The process according to claim 1 , wherein a residual carbon dioxide content in the treated fluid stream is at least 0.5% by volume.

8. The process according to claim 1 , wherein the laden absorbent is regenerated by at least one selected from the group consisting of heating, decompressing and stripping with an inert fluid.

9. The process according to claim 1 , wherein R 7 is C 2 -C 5 -hydroxyalkyl.

10. The process according to claim 1 , wherein R 5 is NR 6 R 7 ; R 6 is selected from hydrogen and C 1 -C 5 -alkyl and R 7 is C 1 -C 5 -alkyl, with the proviso that, when R 6 is hydrogen, R 7 is C 3 -C 5 -alkyl bonded to the nitrogen atom via a secondary or tertiary carbon atom.

11. The process according to claim 10 , wherein the amine of formula (I) is selected from the group consisting of:
4-(N,N-dimethylamino)-2,2,6,6-tetramethylpiperidine,
4-(N,N-diethylamino)-2,2,6,6-tetramethylpiperidine,
4-isopropylamino-2,2,6,6-tetramethylpiperidine, and
4-(tert-butylamino)-2,2,6,6-tetramethylpiperidine.

Assignees

• Basf Se

Inventors

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

Classifications

• C10L3/102

  of acid contaminants · CPC title

• B01D2252/20442

  containing a piperidine-ring · CPC title

• C10L3/104

  Carbon dioxide · CPC title

• B01D53/1468

  Removing hydrogen sulfide · CPC title

• C10L3/103

  Sulfur containing contaminants · CPC title