REMOVAL OF CARBON DIOXIDE FROM FLUE GASES

• US 20090199711A1
• Filed: 06/13/2007
• Published: 08/13/2009
• Est. Priority Date: 06/13/2006
• Status: Active Grant

• Current Assignee: BASF SE
• Original Assignee: BASF SE
• Inventors: Asprion, Norbert, Clausen, Iven, Lichtfers, Ute
• Granted Patent: US 7,887,620 B2
• Time in Patent Office: Days
• US Class Current: 95/161
• 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 description is given of a process for removing carbon dioxide from gas streams in which the partial pressure of the carbon dioxide is less than 200 mbar, in particular flue gases, the gas stream being contacted with a liquid absorption medium which comprises an aqueous solution (A) of a tertiary aliphatic alkanolamine and (B) an activator of the formula

R¹—NH—R²—NH₂,

where R¹ is C₁-C₆-alkyl and R² is C₂-C₆-alkylene, the sum of the concentrations of A and B being 2.5 to 7 mol/l, and the molar ratio of B to A being in the range of 1:3 to 1.5:1. The activator is, for example, 3-methylaminopropylamine, the tertiary aliphatic amine methyldiethanolamine, methyidiisopropanolamine or n-butyldiethanolamine. The process permits substantial removal of carbon dioxide and the regeneration of the absorption medium is possible with relatively low energy consumption.

Claims

1. A process for removing carbon dioxide from a gas stream in which the partial pressure of the carbon dioxide in the gas stream is less than 200 mbar, the gas stream being contacted with a liquid absorption medium which comprises an aqueous solution of

(A) a tertiary aliphatic alkanolamine and

(B) an activator of the formula

R¹—

NH—

R²—

NH₂,

where R¹ is C₁-C₆-alkyl and R² is C₂-C₆-alkylene,

the sum of the concentrations of A and B in the absorption medium being 2.5 to 7 mol/l and the molar ratio of B to A being in the range from 1;

3 to 1.5;

1.

2. The process according to claim 1, wherein the activator is 3-methylamino-propylamine.

3. The process according to claim 1, wherein the tertiary aliphatic amine A is selected from methyldiethanolamine, methyldiisopropanolamine and n-butyldiethanolamine.

4. The process according to claim 1, wherein the sum of the concentrations of A and B in the absorption medium is 2.8 to 6.3 mol/l.

5. The process according to claim 1, wherein the molar ratio of B to A is in the range of 1:

2.5 to 1.3;

1.

6. The process according to claim 1, wherein the gas stream originates from

a) the oxidation of organic substances,

b) the composting or storage of waste materials comprising organic substances, or

c) the bacterial decomposition of organic substances.

7. The process according to claim 1, wherein the loaded absorption medium is regenerated by

a) heating,

b) expansion,

b) stripping with an inert fluid

or a combination of two or all of these measures.

8. The process according to claim 2, wherein the tertiary aliphatic amine A is selected from methyldiethanolamine, methyldiisopropanolamine and n-butyl-diethanolamine.

9. The process according to claim 2, wherein the sum of the concentrations of A and B in the absorption medium is 2.8 to 6.3 mol/l.

10. The process according to claim 3, wherein the sum of the concentrations of A and B in the absorption medium is 2.8 to 6.3 mol/l.

11. The process according to claim 2, wherein the molar ratio of B to A is in the range of 1:

2.5 to 1.3;

1.

12. The process according to claim 3, wherein the molar ratio of B to A is in the range of 1:

2.5 to 1.3;

1.

13. The process according to claim 4, wherein the molar ratio of B to A is in the range of 1:

2.5 to 1.3;

1.

14. The process according to claim 2, wherein the gas stream originates from

a) the oxidation of organic substances,

b) the composting or storage of waste materials comprising organic substances, or

c) the bacterial decomposition of organic substances.

15. The process according to claim 3, wherein the gas stream originates from

a) the oxidation of organic substances,

b) the composting or storage of waste materials comprising organic substances, or

c) the bacterial decomposition of organic substances.

16. The process according to claim 4, wherein the gas stream originates from

a) the oxidation of organic substances,

b) the composting or storage of waste materials comprising organic substances, or

c) the bacterial decomposition of organic substances.

17. The process according to claim 5, wherein the gas stream originates from

a) the oxidation of organic substances,

b) the composting or storage of waste materials comprising organic substances, or

c) the bacterial decomposition of organic substances.

18. The process according to claim 2, wherein the loaded absorption medium is regenerated by

a) heating,

b) expansion,

c) stripping with an inert fluid

or a combination of two or all of these measures.

19. The process according to claim 3, wherein the loaded absorption medium is regenerated by

a) heating,

b) expansion,

d) stripping with an inert fluid

or a combination of two or all of these measures.

20. The process according to claim 4, wherein the loaded absorption medium is regenerated by

a) heating,

b) expansion,

e) stripping with an inert fluid

or a combination of two or all of these measures.