PROCESS AND APPARATUS FOR SEPARATING ENTRAINED AMINES FROM A GAS STREAM

• US 20170246586A1
• Filed: 10/27/2015
• Published: 08/31/2017
• Est. Priority Date: 10/27/2014
• Status: Abandoned Application

• Current Assignee: Carbonoro B.V.
• Original Assignee: Carbonoro B.V.
• Inventors: Jurg, Immanuel
• Application Number:
  US15/521,862
• Publication Number:
  US 20170246586A1
• Time in Patent Office: Days
• CPC Class Codes: B01D 2252/20421 Primary amines
• CPC Class Codes: B01D 2252/20426 Secondary amines
• CPC Class Codes: B01D 2252/20431 Tertiary amines
• CPC Class Codes: B01D 2252/20436 Cyclic amines
• CPC Class Codes: B01D 2257/304 Hydrogen sulfide
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 2258/0283 Flue gases
• CPC Class Codes: B01D 2258/05 Biogas
• CPC Class Codes: B01D 53/1425 Regeneration of liquid absorbents
• CPC Class Codes: B01D 53/1462 Removing mixtures of hydrogen sulfide and carbon dioxide
• CPC Class Codes: B01D 53/1468 Removing hydrogen sulfide
• CPC Class Codes: B01D 53/1475 Removing carbon dioxide
• CPC Class Codes: F23J 15/04 using washing fluids scrubbers for removing solids only F23J15/022
• CPC Class Codes: F23J 2219/40 Sorption with wet devices, e.g. scrubbers
• CPC Class Codes: Y02C 20/40 of CO2
• CPC Class Codes: Y02E 20/32 Direct CO2 mitigation

Abstract

This disclosure relates to a process for removing acid gases from a gas stream enriched in acid gases, wherein: (a) the gas stream enriched in acid gases is contacted in an absorption zone with an absorption medium, wherein the absorption medium is an aqueous medium comprising an amine, to form a gas stream depleted in acid gases which comprises an entrained amine and an absorption medium enriched in acid gases; and (b) treating the gas stream depleted in acid gases which comprises an entrained amine in a scrubbing zone with a scrubbing medium, wherein the scrubbing medium is an aqueous medium comprising an amine, the amount of amine comprised by the scrubbing medium being about 0 to about 10.0 wt. %, to form a gas stream depleted in acid gases and in amine and a scrubbing medium enriched in amine.

Claims

1. A process for removing acid gases from a gas stream enriched in acid gases, wherein:

(a) the gas stream enriched in acid gases is contacted in an absorption zone with an absorption medium, wherein the absorption medium is an aqueous medium comprising an amine, to form a gas stream depleted in acid gases which comprises an entrained amine and an absorption medium enriched in acid gases; and

(b) treating the gas stream depleted in acid gases which comprises an entrained amine in a first scrubbing zone with a first scrubbing medium, wherein the first scrubbing medium is an aqueous medium comprising an amine, the amount of amine comprised by the scrubbing medium being about 0 to about 10.0 wt. %, to form a first gas stream depleted in acid gases and in amine and a first scrubbing medium enriched in amine;

wherein the amine has a partition coefficient log P of more than −

0.5 and wherein the scrubbing medium originates from a regeneration unit.

2. The process according to claim 1, wherein the amount of amine comprised by the scrubbing medium is about 0.1 to about 6.0 wt. %.

3. The process according to claim 1, wherein the scrubbing medium has a pH in the range of about 7 to about 11.

4. The process according to claim 1, wherein step (b) is performed countercurrently.

5. The process according to claim 1, wherein the scrubbing zone is a packed column.

6. The process according to claim 1, wherein the scrubbing medium enriched in amine is returned to a regeneration unit.

7. The process according to claim 1, wherein the amine has a partition coefficient log P of not higher than 3.

8. The process according to claim 1, wherein the amine is selected from the group consisting of primary amines, secondary amines, tertiary amines and mixtures thereof.

9. The process according to claim 8, wherein the amine is a cyclic amine.

10. The process according to claim 9, wherein the amine is N,N-dimethylcyclohexylamine (DMCA), N-methylcyclohexylamine (MCA) or a combination thereof.

11. The process according to claim 1, wherein the acid gases are carbon dioxide, hydrogen sulphide or a mixture thereof.

12. The process according to claim 1, wherein the gas stream enriched in acid gases is a biogas.

13. The process according to claim 1, said process further comprising step (c), said step (c) comprising treating the first gas stream depleted in acid gases and in amine in a second scrubbing zone with a second scrubbing medium, wherein the second scrubbing medium is an aqueous medium comprising an amine, the amount of amine comprised by the second scrubbing medium being about 0 to about 6.0 wt. %, to form a second gas stream depleted in acid gases and in amine and a second scrubbing medium enriched in amine.

14. The process according to claim 1, wherein the first and/or the second scrubbing medium enriched in amine are subjected to a separation process.

15. The process according to claim 14, wherein the first and/or the second scrubbing medium enriched in amine is heated to a temperature in the range of about 40°

to about 90°

C. which results into the formation of an aqueous phase depleted in amine and a non-aqueous phase enriched in amine, where after the two phases are separated.