CO 2 REMOVAL FROM GASES BY MEANS OF AQUEOUS AMINE SOLUTIONS WITH THE ADDITION OF A STERICALLY HINDERED AMINE

• US 20120279393A1
• Filed: 12/21/2010
• Published: 11/08/2012
• Est. Priority Date: 01/05/2010
• Status: Active Grant

• Current Assignee: Thyssenkrupp Uhde GmbH (Thyssenkrupp AG)
• Original Assignee: Thyssenkrupp Uhde GmbH (Thyssenkrupp AG)
• Inventors: Menzel, Johannes, Von Morstein, Olaf
• Granted Patent: US 8,920,544 B2
• Time in Patent Office: Days
• US Class Current: 95/161
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 53/1475 Removing carbon dioxide
• CPC Class Codes: B01D 53/1493 Selection of liquid materials for use as absorbents
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02C 20/40 of CO2

Abstract

A method for removing acid gases from a fluid flow using an absorbent including an aqueous solution with at least two different amines. An amine in a proportion of greater than 50 wt. % of the total amine amount in the aqueous solution is the first amine component in the aqueous solution, and a sterically hindered amine in a proportion of less than 50 wt. % is the second amine component in the aqueous solution. The fluid flow is brought into contact with the absorbent at a partial pressure of <200 mbar.

Claims

1. Use of an absorbent for the removal of sour gases from a fluid stream, the absorbent consisting of an aqueous solution with at least two different amines, with

any arbitrary amine with a share of more than 50 wt. % in the total amine content of the aqueous solution constituting the first amine component in the aqueous solution, and with

a sterically hindered amine with a share of less than 50 wt. % in the total amine content constituting the second amine component in the aqueous solution.

the fluid stream being brought into contact with the absorbent at a partial pressure of <

200 mbar.

2. Use of an absorbent according to claim 1, with the share of the arbitrary amine in the total amine content of the aqueous solution ranging between 60 wt. % and 90 wt. % and preferably between 70 wt. % and 85 wt. %.

3. Use of an absorbent according to claim 1, with the share of the sterically hindered amine in the total amine content of the aqueous solution ranging between 1 wt. % and 40 wt. % and preferably being <

15 wt. %.

4. Use of an absorbent according to one of claims 1 to 3, the sterically hindered amine being selected from a group comprising

(i) amines with a primary amino group which is bound to a tertiary carbon atom,

(ii) amines with a secondary amino group which is bound to a secondary or tertiary carbon atom, and

(iii) amines in which a tertiary or quaternary carbon atom is placed in β

position to the amino group.

5. Use of an absorbent according to claim 4, the sterically hindered amine particularly preferred being 2-amino-2-methyl-1-propanol (AMP).

6. Use of an absorbent according to one of claims 1 to 5, the arbitrary amine being piperazine or a piperazine derivative.

7. Use of an absorbent according to one of claims 1 to 5, the arbitrary amine being an amine with more than one amino group in the molecule, with the amino group existing in primary and in secondary structure as well as in mixed primary and secondary structure.

8. Use of an absorbent according to one of claims 1 to 5, the arbitrary amine being a diamine of the formula H₂N—

R2-NH₂, where R2 represents a C₂ to C₆ alkyl group.

9. Use of an absorbent according to one of claims 1 to 5, the arbitrary amine being selected from a group comprising ethylene diamine, 1,4 diaminobutane, 1,3 diaminopropane, 1,2 diaminopropane, 2,2 dimethyl-1,3 diaminopropane, hexamethylene diamine, 3-methyl aminopropylamine, 3-(dimethyl amino)propylamine, 3-(diethyl amino)propylamine, 4-dimethyl aminobutylamine and 5-dimethyl aminopentylamine, 1,1,N,N-tetramethyl ethane diamine, 2,2,N,N-tetramethyl-1,3-propane diamine, N,N′

-dimethyl-1,3-propane diamine and N,N′

bis(2-hydroxyethyl)ethylene diamine.

10. Use of an absorbent according to one of claims 1 to 5, the arbitrary amine being a diamine of the formula R1-HN—

R2-NH₂, where R1 represents a C₁-C₆ alkyl and R2 a C₂ to C₆ alkyl group.

11. Use of an absorbent according to one of claims 1 to 5, the arbitrary amine being a polyalkylene polyamine selected from a group comprising diethylene triamine, triethylene tetramine, tetraethylene pentamine, tris(3-aminopropyl)amine, tris(2-amino ethyl)amine, bis(3-dimethyl aminopropyl)amine, methyl-bis(2-methyl aminoethyl)amine.

12. Use of an absorbent according to one of claims 1 to 5, the arbitrary amine being a primary or a secondary amine.

13. Use of an absorbent according to one of claims 1 to 5, the arbitrary amine being a tertiary amine of the general formula N(R1)₂₋

n(R2)_1+n,

where R1 represents an alkyl group and R2 a hydroxylalkyl group.

14. Use of an absorbent according to one of claims 1 to 5, the arbitrary amine being a tertiary amine of the general formula (R1)₂₋

n(R2)_nN—

X—

N(R1)<sub>2−

m</sub>(R2)_m,

where R1 represents an alkyl group, R2 a hydroxyalkyl group, X an alkylene group which is interrupted once or several times by oxygen and n and m represent an integer from 0 to 2, or two remainders R1 and R2 bound to different nitrogen atoms together represent an alkylene group.

15. Use of an absorbent according to claim 13 or 14, the arbitrary amine being selected from a group comprising bis-dimethylaminoethyl ether, tris(2-hydroxyethyl)amine, tris(2-hydroxypropyl)amine, tributanolamine, bis(2-hydroxyethyl)-methylamine, 2-diethylaminoethanol, 2-dimethylaminoethanol, 3-dimethylamino-1-propanol, 3-diethylamino-1-propanol, 2-diisopropylaminoethanol, N,N-bis(2-hydroxypropyl)methylamin (methyldiisopropanolamin, MDI PA), N,N,N′

,N′

-tetramethylethylendiamine, N,N-diethyl-N′

,N′

-dimethylethylendiamine, N,N,N′

,N′

-tetraethylethylendiamin, N,N′

,N′

-tetramethylpropandiamine, N,N,N′

,N′

-tetraethylpropandiamine, N,N-dimethyl-N′

,N′

-diethylethylendiamine, 2-(2-dimethylaminoethoxy)-N,N-dimethylethanamine;

1,4-diazabicyclo[2.2.2]octane (DABCO);

N,N,N′

-trimethylaminoethylethanolamine, N,N′

-dimethylpiperazine and N,N′

-bis(hydroxyethyl)piperazine, bis-dimethylaminoethyl ether being used with particular preference.

16. Use of an absorbent for the removal of carbon dioxide from a fluid stream according to one of claims 1 to 15, the laden absorbent being regenerated by

i) heating,

ii) depressurising,

iii) stripping with stripping vapours produced by internal evaporation of the solvent,

iv) stripping with an inert fluid

or a combination of two or all of these measures.