Method for absorbing CO2 from a gas mixture

Patent metadata

Field	Value
Publication number	US-9630140-B2
Application number	US-201314399139-A
Country	US
Kind code	B2
Filing date	Apr 22, 2013
Priority date	May 7, 2012
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

In a method of absorbing CO 2 from a gas mixture the use of an absorption medium comprising water and at least one amine of formula (I)

where
R 1 is a —(CH 2 ) n —(XCH 2 CH 2 ) m —Y—R 3 radical where
R 3 =hydrogen or an alkyl radical having from 1 to 6 carbon atoms,
X and Y are each, independently of one another, NR 3 , oxygen, SO or SO 2 , where in the case of Y═SO and in the case of Y═SO 2 , R 3 is not hydrogen, and Y—R 3 can be an N-morpholinyl radical or an N-piperazyl radical,
n=2 to 4,
m=0 to 4 and
R 2 is hydrogen, an alkyl radical having from 1 to 6 carbon atoms or a radical R 1 ,
where m is not 0 when R 2 is not a radical R 1 , Y═NR 3 and Y—R 3 is not an N-morpholinyl radical and not an N-piperazyl radical,
makes it possible to avoid precipitation of a solid during the absorption of CO 2 and a separation into two liquid phases during the regeneration of the absorption medium.

First claim

The invention claimed is:

1. A method of absorbing CO 2 from a gas mixture by contacting the gas mixture with an absorption medium wherein the absorption medium comprises water and at least one amine of formula (I):

where
R 1 is a —(CH 2 ) n —(XCH 2 CH 2 ) m —Y—R 3 radical where
R 3 =hydrogen or an alkyl radical having from 1 to 6 carbon atoms,
X and Y are each, independently of one another, NR 3 , oxygen, SO or SO 2 , where in the case of Y═SO and in the case of Y═SO 2 , R 3 is not hydrogen, and Y—R 3 can be an N-morpholinyl radical or an N-piperazyl radical,
n=2 to 4,
m=0 to 4 and
R 2 is hydrogen, an alkyl radical having from 1 to 6 carbon atoms or a radical R 1 , where m is different from 0 when R 2 is not a radical R 1 , Y═NR 3 and Y—R 3 is not an N-morpholinyl radical and not an N-piperazyl radical.

2. The method of claim 1 , wherein X and Y in formula (I) are each, independently of one another, NR 3 or oxygen.

3. The method of claim 2 , wherein Y in formula (I) is oxygen.

4. The method of claim 3 , wherein R 3 in formula (I) is methyl or hydrogen.

5. The method of claim 3 , wherein m in formula (I) is 0.

6. The method of claim 1 , wherein Y—R 3 in formula (I) is an N-morpholinyl radical or an N-piperazyl radical.

7. The method of claim 6 , wherein m in formula (I) is 0.

8. The method of claim 1 , wherein n in formula (I) is 2 or 3.

9. The method of claim 8 , wherein n in formula (I) is 2.

10. The method of claim 1 , wherein the absorption medium has a content of amines of formula (I) of from 10 to 60% by weight.

11. The method of claim 10 , wherein the absorption medium has a content of amines of formula (I) of from 20 to 50% by weight.

12. The method of claim 1 , wherein the gas mixture is a combustion off-gas, a natural gas or a biogas.

13. The method of claim 1 , wherein CO 2 absorbed in the absorption medium is desorbed again by an increase in temperature, a reduction of pressure or both and after this desorption of CO 2 the absorption medium is used again for absorbing CO 2 .

14. The method of claim 13 , wherein the absorption is carried out at a temperature in the range from 0 to 80° C. and the desorption is carried out at a higher temperature in the range from 50 to 200° C.

15. The method of claim 13 , wherein the absorption is carried out at a pressure in the range from 0.8 to 90 bar and the desorption is carried out at a lower pressure in the range from 0.01 to 10 bar.

16. The method of claim 1 , wherein said amine of formula (I) is selected from the group consisting of 4-(2-hydroxyethylamino)-2,2,6,6-tetramethylpiperidine, 4-[bis(2-hydroxyethy)amino]-2,2,6,6-tetramethylpiperidine, 4-(2-methoxyethylamino)-2,2,6,6-tetramethylpiperidine, 4-(2-hydroxyethylaminoethylamino)-2,2,6,6-tetramethylpiperidine, 4-(2-piperazinoethylamino)-2,2,6,6-tetramethylpiperidine and 4-(2-morpholinopropylamino)-2,2,6,6-tetramethylpiperidine.

Assignees

• Evonik Degussa Gmbh

Inventors

• Willy Benjamin
• Rinker Stefanie
• Neumann Manfred
• Niemeyer Jochen
• Keup Michael
• Witthaut Daniel
• Seiler Matthias
• Rolker Jörn
• Schneider Rolf
• Dembkowski Daniel
• Brehme Volker

Classifications

• B01D2258/0283

  Flue gases · CPC title

• B01D2256/24

  Hydrocarbons · CPC title

• B01D2258/025

  from metallurgy plants · CPC title

• B01D2257/504

  Carbon dioxide · CPC title

• B01D2252/20478

  Alkanolamines · CPC title