Hydrogen gas separation using organic-vapor-resistant membranes

• US 6,544,316 B2
• Filed: 12/28/2001
• Issued: 04/08/2003
• Est. Priority Date: 05/19/2000
• Status: Expired due to Term

• Current Assignee: Membrane Technology and Research, Inc.
• Original Assignee: Membrane Technology and Research, Inc.
• Inventors: Pinnau, Ingo, He, Zhenjie, Amo, Karl D., Daniels, Ramin, Baker, Richard W., Da Costa, Andre R.
• Primary Examiner(s): Spitzer, Robert H.
• Application Number:
  US10/033,211
• Publication Number:
  US 20020104435A1
• Time in Patent Office: 466 Days
• Field of Search: 95/45, 95/47--55, 95/96--06, 96/4, 96/8, 96/10, 96/13, 96/14, 961/08, 961/30
• US Class Current: 95/55
• CPC Class Codes: B01D 53/228 characterised by specific membranes
• CPC Class Codes: B01D 69/02 characterised by their properties
• CPC Class Codes: B01D 71/32 containing fluorine atoms
• CPC Class Codes: B01D 71/44 Polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds, not provided for in a single one of groups B01D71/26-B01D71/42
• CPC Class Codes: B01D 71/522 Aromatic polyethers
• CPC Class Codes: B01D 71/64 Polyimides; Polyamide-imides; Polyester-imides; Polyamide acids or similar polyimide precursors

Abstract

A process for separating hydrogen from a multicomponent gas mixture containing hydrogen and a hydrocarbon, using gas-separation membranes selective for hydrogen over the hydrocarbon. The membranes use a selective layer made from a polymer having repeating units of a fluorinated polymer, and demonstrate good resistance to plasticization by the organic components in the gas mixture under treatment, and good recovery after exposure to liquid aromatic hydrocarbons.

Claims

1. A process for separating hydrogen from a gaseous hydrocarbon in a multicomponent gas mixture comprising hydrogen, the gaseous hydrocarbon, and a third gaseous component, the process comprising the steps of:

(a) bringing the gas mixture into contact with the feed side of a separation membrane having a feed side and a permeate side, the separation membrane having a selective layer comprising;

a polymer comprising repeat units of a fluorinated cyclic structure of an at least 5-member ring, the polymer having a fractional free volume no greater than about 0.3;

(b) providing a driving force for transmembrane permeation;

(c) withdrawing from the permeate side a permeate stream enriched in hydrogen compared to the gas mixture;

(d) withdrawing from the feed side a residue stream depleted in hydrogen compared to the gas mixture.

2. The process of claim 1, wherein the gaseous hydrocarbon is chosen from the group consisting of methane, ethane and C₃₊ hydrocarbons.

3. The process of claim 1, wherein the gaseous hydrocarbon is an olefin.

4. The process of claim 1, wherein the gaseous hydrocarbon is an aromatic compound.

5. The process of claim 1, wherein the gaseous hydrocarbon is chosen from the group consisting of halogenated compounds, amines, ketones and alcohols.

6. The process of claim 1, wherein the third gaseous component is a hydrocarbon.

7. The process of claim 1, wherein the third gaseous component is chosen from the group consisting of methane, ethane and C₃₊ hydrocarbons.

8. The process of claim 1, wherein the gas mixture is a refinery gas stream.

9. The process of claim 1, wherein the gas mixture is a petrochemical plant gas stream.

10. The process of claim 1, wherein the polymer comprises a perfluorinated polymer.

11. The process of claim 1, wherein the polymer is formed from a monomer selected from the group consisting of fluorinated dioxoles, fluorinated dioxolanes and fluorinated cyclically polymerizable alkyl ethers.

12. The process of claim 1, wherein the polymer is formed from a perfluorinated polyimide.

13. The process of claim 1, wherein the repeat unit is 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxole.

14. The process of claim 1, wherein the polymer is a polyperfluoro (alkenyl vinyl ether).

15. The process of claim 1, wherein the polymer comprises a copolymer.

16. The process of claim 1, wherein the polymer comprises a copolymer having repeat units as recited in claim 1 copolymerized with repeat units of a second fluorinated monomer.

17. The process of claim 1, wherein the polymer comprises a copolymer having repeat units as recited in claim 1 copolymerized with repeat units of tetrafluoroethylene.

18. The process of claim 1, wherein the polymer has the formula:

where x and y represent the relative proportions of the dioxole and the tetrafluoroethylene blocks, such that x+y=1.

19. The process of claim 1, wherein the polymer has the formula:

where n is a positive integer.

20. The process of claim 1, wherein the separation membrane is a composite membrane comprising the selective layer supported on a microporous support membrane.

21. The process of claim 1, wherein the gas mixture, as brought into contact with the feed side, has a total C₃₊ hydrocarbons partial pressure of at least about 25 psia.

22. The process of claim 1, wherein the separation membrane provides a pressure-normalized hydrogen flux as measured with pure gas at 25°

C. of at least about 50 GPU.

23. The process of claim 1, further comprising passing the permeate stream to additional separation treatment.

24. The process of claim 1, further comprising passing the residue stream to additional separation treatment.

25. The process of claim 1, wherein the separation membrane exhibits a mixed-gas selectivity for hydrogen over methane as measured at the operating conditions of the process of at least about 10.

26. The process of claim 1, further comprising passing the residue stream to a fuel gas supply.

27. The process of claim 1, further comprising passing the permeate stream to a pressure swing adsorption unit to produce a high-purity hydrogen stream.

28. The process of claim 1, wherein the gas mixture comprises tail gas from a pressure swing adsorption unit.

29. The process of claim 1, wherein the gas mixture comprises a process or off-gas stream from a hydroprocessor.

30. The process of claim 1, wherein the gas mixture comprises a process or off-gas stream from a catalytic reformer.

31. The process of claim 1, wherein the gas mixture comprises a process or off-gas stream from a fluid catalytic cracker.

32. The process of claim 1, wherein the gas mixture comprises a process or off-gas stream from a stream cracker.

33. The process of claim 1, wherein the gas mixture comprises a process or off-gas stream from a steam reformer.

34. The process of claim 1, further comprising removing a contaminant material that has been brought into a module housing the separation membrane during operation of steps (a) through (d) by:

(e) discontinuing steps (a) through (d); and

(f) flushing the module with an organic solvent.

35. A process for separating hydrogen from a gaseous hydrocarbon in a multicomponent gas mixture comprising hydrogen, the gaseous hydrocarbon, and a third gaseous component, the process comprising the steps of:

(a) bringing the gas mixture into contact with the feed side of a separation membrane having a feed side and a permeate side, the membrane having a selective layer comprising a polymer having;

(i) a ratio of fluorine to carbon atoms in the polymer greater than 1;

1;

(ii) a fractional free volume no greater than about 0.3; and

(iii) a glass transition temperature of at least about 100°

C.;

 

and the separation membrane being characterized by a post-exposure selectivity for hydrogen over the gaseous hydrocarbon, after exposure of the separation membrane to liquid toluene and subsequent drying, that is at least about 65% of a pre-exposure selectivity for hydrogen over the gaseous hydrocarbon, as measured pre- and post-exposure with a test gas mixture of the same composition and under like conditions;

(b) providing a driving force for transmembrane permeation;

(c) withdrawing from the permeate side a permeate stream enriched in hydrogen compared to the gas mixture;

(d) withdrawing from the feed side a residue stream depleted in hydrogen compared to the gas mixture.

36. The process of claim 35, wherein the gaseous hydrocarbon is chosen from the group consisting of methane, ethane and C₃₊ hydrocarbons.

37. The process of claim 35, wherein the gaseous hydrocarbon is an olefin.

38. The process of claim 35, wherein the gaseous hydrocarbon is an aromatic compound.

39. The process of claim 35, wherein the gaseous hydrocarbon is chosen from the group consisting of halogenated compounds, amines, ketones and alcohols.

40. The process of claim 35, wherein the third gaseous component is a hydrocarbon.

41. The process of claim 35, wherein the third gaseous component is chosen from the group consisting of methane, ethane and C₃₊ hydrocarbons.

42. The process of claim 35, wherein the gas mixture is a refinery gas stream.

43. The process of claim 35, wherein the gas mixture is a petrochemical plant gas stream.

44. The process of claim 35, wherein the selective layer comprises a perfluorinated polymer.

45. The process of claim 35, wherein the selective layer comprises a polymer formed from a monomer selected from the group consisting of fluorinated dioxoles, fluorinated dioxolanes and fluorinated cyclically polymerizable alkyl ethers.

46. The process of claim 35, wherein the selective layer comprises a perfluorinated polyimide.

47. The process of claim 35, wherein the selective layer comprises a copolymer.

48. The process of claim 35, wherein the selective layer comprises a copolymer formed from fluorinated dioxole and tetrafluoroethylene repeat units.

49. The process of claim 35, wherein the selective layer comprises a polymer having the formula:

where x and y represent the relative proportions of the dioxole and the tetrafluoroethylene blocks, such that x+y=1.

50. The process of claim 35, wherein the selective layer comprises a polymer having the formula:

where n is a positive integer.

51. The process of claim 35, wherein the separation membrane is a composite membrane comprising the selective layer supported on a microporous support membrane.

52. The process of claim 35, wherein the gas mixture, as brought into contact with the feed side, has a total C₃₊ hydrocarbons partial pressure of at least about 25 psia.

53. The process of claim 35, wherein the separation membrane provides a pressure-normalized hydrogen flux as measured with pure gas at 25°

C. of at least about 50 GPU.

54. The process of claim 35, further comprising passing the permeate stream to additional separation treatment.

55. The process of claim 35, further comprising passing the residue stream to additional separation treatment.

56. The process of claim 35, wherein the separation membrane exhibits a mixed-gas selectivity for hydrogen over methane as measured at the operating conditions of the process of at least about 10.

57. The process of claim 35, further comprising passing the residue stream to a fuel gas supply.

58. The process of claim 35, further comprising passing the permeate stream to a pressure swing adsorption unit to produce a high-purity hydrogen stream.

59. The process of claim 35, wherein the gas mixture comprises tail gas from a pressure swing adsorption unit.

60. The process of claim 35, wherein the gas mixture comprises a process or off-gas stream from a hydroprocessor.

61. The process of claim 35, wherein the gas mixture comprises a process or off-gas stream from a catalytic reformer.

62. The process of claim 35, wherein the gas mixture comprises a process or off-gas stream from a fluid catalytic cracker.

63. The process of claim 35, wherein the gas mixture comprises a process or off-gas stream from a stream cracker.

64. The process of claim 35, wherein the gas mixture comprises a process or off-gas stream from a steam reformer.

65. The process of claim 35, further comprising removing a contaminant material that has been brought into a module housing the separation membrane during operation of steps (a) through (d) by:

(e) discontinuing steps (a) through (d); and

(f) flushing the module with an organic solvent.