Hydrogen recovery from hydrocarbon synthesis processes

• US 20070123595A1
• Filed: 12/13/2006
• Published: 05/31/2007
• Est. Priority Date: 03/08/2004
• Status: Active Grant

• Current Assignee: Chevron USA Incorporated (Chevron Corp.)
• Original Assignee: Chevron USA Incorporated (Chevron Corp.)
• Inventors: Chinn, Daniel, Lowe, Clifford
• Granted Patent: US 7,745,502 B2
• Time in Patent Office: Days
• US Class Current: 518/726
• CPC Class Codes: C01B 2203/0283 containing a CO-shift step, i.e. a water gas shift step
• CPC Class Codes: C01B 2203/0405 Purification by membrane separation
• CPC Class Codes: C01B 2203/043 Regenerative adsorption process in two or more beds, one for adsorption, the other for regeneration
• CPC Class Codes: C01B 2203/0475 the impurity being carbon dioxide
• CPC Class Codes: C01B 2203/0495 the impurity being water
• CPC Class Codes: C01B 2203/146 At least two purification steps in series
• CPC Class Codes: C01B 3/12 by reaction of water vapour with carbon monoxide
• CPC Class Codes: C01B 3/501 by diffusion
• CPC Class Codes: C01B 3/56 by contacting with solids; Regeneration of used solids C01B3/508 takes precedence
• CPC Class Codes: C10G 2/30 from carbon monoxide with hydrogen
• CPC Class Codes: C10K 1/32 with selectively adsorptive solids, e.g. active carbon
• CPC Class Codes: C10K 3/04 reducing the carbon monoxide content , e.g. water-gas shift [WGS]

Abstract

The invention relates to a process for producing a hydrogen-rich stream from a hydrogen-depleted stream. More particularly, the invention relates to a hydrocarbon synthesis process, by way of example, a Fischer Tropsch process, from which both hydrocarbons and high purity hydrogen are obtained. The process comprises contacting the hydrogen-depleted stream with a reverse-selective membrane to provide a CO₂-enriched permeate and a hydrogen-containing retentate. The high purity hydrogen is produced from the hydrogen-containing retentate. The high purity hydrogen thus obtained may be used in a process selected from the group consisting of upgrading hydrocarbons produced from the hydrocarbon synthesis process, hydrotreating a natural gas stream, recycling to the hydrocarbon synthesis reaction unit, high purity hydrogen production, catalyst rejuvenation, and combinations thereof.

Claims

1. A process for providing a hydrogen-rich stream comprising:

a) performing a hydrocarbon synthesis process using syngas;

b) isolating a gaseous stream comprising hydrogen from the hydrocarbon synthesis process;

c) contacting the gaseous stream comprising hydrogen with a reverse selective membrane to provide a CO₂-enriched permeate and a hydrogen-containing retentate;

d) passing the retentate through a water gas shift reactor to provide a hydrogen-containing stream; and

e) passing the hydrogen-containing stream through a pressure swing adsorption unit to provide a hydrogen-rich stream comprising greater than 90 vol. % hydrogen.

2. The process according to claim 1, wherein the hydrocarbon synthesis process is a Fischer Tropsch process.

3. The process according to claim 1, wherein the process further comprises passing the hydrogen-containing stream through a vapor-liquid separator to remove water.

4. The process according to claim 1, wherein the process further comprises using the hydrogen-rich stream for a process selected from the group consisting of (i) upgrading a hydrocarbon product stream from the hydrocarbon synthesis process;

(ii) hydrotreating a natural gas stream;

(iii) recycling the hydrogen-rich stream to a hydrocarbon synthesis reaction unit;

(iv) hydrogen production for uses outside the hydrocarbon synthesis process;

(v) rejuvenating a hydrocarbon synthesis reaction catalyst; and

(vi) combinations thereof.

5. The process according to claim 1, wherein the hydrogen-containing retentate is at a pressure of ≧

about 100 psig.

6. The process according to claim 1, wherein the hydrogen-containing retentate is at a pressure of ≧

about 200 psig.

7. The process according to claim 3, wherein the gaseous stream comprising hydrogen comprises less than 35 vol. % hydrogen and the hydrogen-containing stream comprises greater than 40 vol. % hydrogen.

8. The process according to claim 1, wherein the hydrogen-rich stream comprising greater than 99 vol. % hydrogen.

9. The process according to claim 1, wherein the gaseous stream comprises CO₂, CO, H₂O (g), gaseous C₁-C₅ hydrocarbons, and less than 35 vol. % H₂.

10. The process according to claim 1, wherein the gaseous stream comprising hydrogen is isolated from a source selected from the group consisting of (i) a tail gas from a hydrocarbon synthesis reaction unit;

(ii) the syngas prior to performing the hydrocarbon synthesis reaction;

(iii) a tail gas from an upgrading process; and

(iv) combinations thereof.

11. A process for providing a hydrogen-rich stream comprising:

a) performing a hydrocarbon synthesis process using syngas;

b) isolating a gaseous stream comprising hydrogen from the hydrocarbon synthesis process;

c) passing the gaseous stream comprising hydrogen through a water gas shift reactor to provide a hydrogen-containing stream;

d) contacting the hydrogen-containing stream with a reverse-selective membrane to provide a CO₂-enriched permeate and a hydrogen-containing retentate; and

e) passing the hydrogen-containing retentate through a pressure swing adsorption unit to provide a hydrogen-rich stream comprising greater than 90 vol. % hydrogen.

12. The process according to claim 11, wherein the hydrocarbon synthesis process is a Fischer Tropsch process.

13. The process according to claim 11, wherein the process further comprises passing the hydrogen-containing stream through a vapor-liquid separator to remove water.

14. The process according to claim 11, wherein the process further comprises using the hydrogen-rich stream for a process selected from the group consisting of (i) upgrading a hydrocarbon product stream from the hydrocarbon synthesis process;

(ii) hydrotreating a natural gas stream;

(iii) recycling the hydrogen-rich stream to a hydrocarbon synthesis reaction unit;

(iv) hydrogen production for uses outside the hydrocarbon synthesis process;

(v) rejuvenating a hydrocarbon synthesis reaction catalyst; and

(vi) combinations thereof.

15. The process according to claim 11, wherein the hydrogen-containing retentate is at a pressure of ≧

about 100 psig.

16. The process according to claim 11, wherein the hydrogen-containing retentate is at a pressure of ≧

about 200 psig.

17. The process according to claim 13, wherein the gaseous stream comprising hydrogen comprises less than 35 vol. % hydrogen and the hydrogen-containing stream comprises greater than 40 vol. % hydrogen.

18. The process according to claim 11, wherein the hydrogen-rich stream comprising greater than 99 vol. % hydrogen.

19. The process according to claim 11, wherein the gaseous stream comprises CO₂, CO, H₂O (g), gaseous C₁-C₅ hydrocarbons, and less than 35 vol. % H₂.

20. The process according to claim 11, wherein the gaseous stream comprising hydrogen is isolated from a source selected from the group consisting of (i) a tail gas from a hydrocarbon synthesis reaction unit;

(ii) the syngas prior to performing the hydrocarbon synthesis reaction;

(iii) a tail gas from an upgrading process; and

(iv) combinations thereof.

21. A process for providing a hydrogen-rich stream comprising:

a) performing a hydrocarbon synthesis process;

b) isolating a hydrogen-depleted stream from the hydrocarbon synthesis process; and

c) isolating a hydrogen-rich stream comprising greater than 90 vol. % hydrogen from the hydrogen-depleted stream by a process comprising contacting the hydrogen-containing stream with a reverse-selective membrane.

22. The process according to claim 21, wherein the hydrocarbon synthesis process is a Fischer Tropsch process.

23. The process according to claim 21, wherein the hydrogen-depleted stream comprises less than 35 vol. % hydrogen.

24. The process according to claim 21, wherein the hydrogen-depleted stream is isolated from a source selected from the group consisting of (i) a tail gas from a hydrocarbon synthesis reaction unit;

(ii) syngas prior to performing the hydrocarbon synthesis reaction;

(iii) a tail gas from an upgrading process; and

(iv) combinations thereof.

25. The process according to claim 21, wherein the process for isolating the hydrogen-rich stream comprising further comprises passing the hydrogen-depleted stream through a water gas shift reactor and through a pressure swing adsorption unit, wherein the hydrogen-depleted stream is contacted with the reverse-selective membrane and passed through the water gas shift reactor prior to the pressure swing adsorption unit.

26. The process according to claim 21, wherein the hydrogen-rich stream comprising greater than 99 vol. % hydrogen.

27. A process for upgrading a hydrocarbon product stream comprising contacting the hydrocarbon product stream with a hydrogen-rich stream, wherein the hydrogen-rich stream is isolated from a stream comprising less than 40% vol. hydrogen.

28. The process according to claim 27, wherein the hydrogen-rich stream is isolated from a stream comprising less than 35% vol. hydrogen and the hydrogen-rich stream comprises greater than 99 vol. % hydrogen.

29. The process according to claim 27, wherein the stream, from which the hydrogen-rich stream is isolated, originates from a source selected from the group consisting of (i) a tail gas from a hydrocarbon synthesis reaction unit;

(ii) syngas prior to performing a hydrocarbon synthesis reaction;

(iii) a tail gas from an upgrading process; and

(iv) combinations thereof.

30. A process for providing a hydrogen-rich stream comprising:

a) performing a hydrocarbon synthesis process using syngas to provide at least one hydrocarbon stream and a hydrogen-depleted stream;

b) isolating a hydrogen-containing stream from the hydrogen-depleted stream by a process comprising contacting with a reverse-selective membrane and performing a water gas shift reaction, wherein the hydrogen concentration on a water-free basis of the hydrogen-containing stream is at least 5 vol. % greater than the hydrogen concentration on a water-free basis of the hydrogen-depleted stream; and

c) passing the hydrogen-containing stream through a pressure swing adsorption unit to provide a hydrogen-rich stream comprising greater than 90 vol. % hydrogen.

31. The process according to claim 30, wherein the hydrogen-depleted stream is contacted with the reverse-selective membrane prior to performing the water gas shift reaction.

32. The process according to claim 30, wherein the water gas shift reaction is performed on the hydrogen-depleted stream prior to contacting with a reverse-selective membrane.

33. The process according to claim 30, wherein the process for isolating a hydrogen-containing stream from the hydrogen-depleted stream further comprises removing water in a vapor-liquid separator.

34. The process according to claim 30, wherein the hydrogen-depleted stream comprises less than 40 vol. % hydrogen.

35. The process according to claim 30, wherein the hydrogen-depleted stream comprises less than 35 vol. % hydrogen.

36. The process according to claim 30, wherein the hydrogen-depleted stream is isolated from a source selected from the group consisting of (i) a tail gas from a hydrocarbon synthesis reaction unit;

(ii) the syngas prior to performing the hydrocarbon synthesis reaction;

(iii) a tail gas from an upgrading process; and

(iv) combinations thereof.

37. The process according to claim 30, wherein the process further comprises using the hydrogen-rich stream for a process selected from the group consisting of (i) upgrading a hydrocarbon product stream from the hydrocarbon synthesis process;

(ii) hydrotreating a natural gas stream;

(iii) recycling the hydrogen-rich stream to a hydrocarbon synthesis reaction unit;

(iv) hydrogen production for uses outside the hydrocarbon synthesis process;

(v) rejuvenating a hydrocarbon synthesis reaction catalyst; and

(vi) combinations thereof.

38. The process according to claim 30, wherein the hydrocarbon synthesis process is a Fischer Tropsch process.