Pre-processing assembly for pre-processing fuel feedstocks for use in a fuel cell system

• US 20060090398A1
• Filed: 11/02/2004
• Published: 05/04/2006
• Est. Priority Date: 11/02/2004
• Status: Abandoned Application

• Current Assignee: Fuelcell Energy Ltd.
• Original Assignee: Fuelcell Energy Ltd.
• Inventors: Katikaneni, Sai P., Daly, Joseph M.
• Application Number:
  US10/979,698
• Publication Number:
  US 20060090398A1
• Time in Patent Office: Days
• US Class Current: 48/127.9
• CPC Class Codes: B01J 19/2485 Monolithic reactors
• CPC Class Codes: B01J 2208/00176 outside the reactor
• CPC Class Codes: B01J 2208/00884 Means for supporting the bed of particles, e.g. grids, bars, perforated plates
• CPC Class Codes: B01J 2208/025 Two or more types of catalyst
• CPC Class Codes: B01J 2219/0004 Processes in series
• CPC Class Codes: B01J 8/0453 the beds being superimposed one above the other
• CPC Class Codes: C01B 2203/0233 the reforming step being a steam reforming step
• CPC Class Codes: C01B 2203/0261 containing a catalytic partial oxidation step [CPO]
• CPC Class Codes: C01B 2203/066 with fuel cells
• CPC Class Codes: C01B 2203/1241 Natural gas or methane
• CPC Class Codes: C01B 2203/1247 Higher hydrocarbons
• CPC Class Codes: C01B 2203/1258 Pre-treatment of the feed
• CPC Class Codes: C01B 2203/127 Catalytic desulfurisation
• CPC Class Codes: C01B 2203/143 Three or more reforming, decomposition or partial oxidation steps in series
• CPC Class Codes: C01B 3/38 using catalysts
• CPC Class Codes: C01B 3/382 Multi-step processes
• CPC Class Codes: C01B 3/386 Catalytic partial combustion
• CPC Class Codes: H01M 2008/1293 Fuel cells with solid oxide electrolytes
• CPC Class Codes: H01M 2008/147 Fuel cells with molten carbonates
• CPC Class Codes: H01M 8/0618 Reforming processes, e.g. autothermal, partial oxidation or steam reforming
• CPC Class Codes: H01M 8/0675 : Removal of sulfur
• CPC Class Codes: Y02E 60/50 : Fuel cells

Abstract

A pre-processing assembly and method for processing fuel feedstock containing oxygen and hydrocarbons having higher and lower hydrocarbon content for a fuel cell, wherein the pre-processing assembly has a deoxidizing bed for reducing oxygen in the fuel feedstock and a pre-reforming bed for reducing higher hydrocarbon content in the fuel feedstock and wherein the deoxidizing bed and the pre-reforming bed are disposed within a common reaction vessel such that the fuel feedstock first passes through the deoxidizing bed and thereafter through the pre-reforming bed. The pre-reforming assembly may further include a propane processor bed for processing propane and propylene in the fuel feedstock, where the propane processor bed is disposed within the common reaction vessel with the deoxidizing bed and the pre-reforming bed.

Claims

1. A pre-processing assembly for processing fuel feedstock for a fuel cell, the fuel feedstock including oxygen and hydrocarbons having higher and lower hydrocarbon content, said pre-processing assembly comprising:

a deoxidizing unit for reducing the oxygen in said fuel feedstock; and

a pre-reforming unit for reducing the higher hydrocarbon content in said fuel feedstock;

and a common vessel;

wherein said deoxidizing unit and said pre-reforming unit are disposed within said common vessel such that said fuel feedstock passes through said deoxidizing unit first and thereafter through said pre-reforming unit.

2. A pre-processing assembly according to claim 1, wherein said deoxidizing unit comprises a deoxidizing bed and said pre-reforming unit comprises a pre-reforming bed, said pre-reforming bed following said deoxidizing bed along the flow path of said fuel feedstock.

3. A pre-processing assembly according to claim 2, wherein said deoxidizing bed comprises a deoxidizing catalyst and said pre-reforming bed comprises a pre-reforming catalyst.

4. A pre-processing assembly according to claim 3, wherein said deoxidizing catalyst is one of Pt—

Pd on alumina catalyst, Pt—

Rh-based catalyst and Rh—

Pd-based alumina catalyst.

5. A pre-processing assembly according to claim 4, wherein said deoxidizing catalyst is G-74D.

6. A pre-processing assembly according to claim 4, wherein said pre-reforming catalyst is a nickel-based catalyst.

7. A pre-processing assembly according to claim 6, wherein said pre-reforming catalyst is one of C11-PR, CRG-F, CRG-LH and G-180.

8. A pre-processing assembly according to claim 7, wherein said deoxidizing catalyst and said pre-reforming catalyst are pellet-shaped catalysts.

9. A pre-processing assembly according to claim 7, wherein each of said deoxidizing catalyst and said pre-reforming catalyst comprises a catalyst-coated ceramic monolith.

10. A pre-processing assembly according to claim 1, wherein said deoxidizing bed in reducing said oxygen produces hydrogen and said pre-reforming bed converts said lower hydrocarbon content to hydrogen to maintain a reducing environment in said pre-reforming bed.

11. A pre-processing assembly according to claim 10, wherein the space velocity of the fuel feedstock in said pre-reforming bed is such that hydrogen back diffusion is developed and maintained in said pre-reforming bed.

12. A pre-processing assembly according to claim 11, wherein the space velocity of said fuel feedstock in said pre-reforming bed is between 2,000 and 5,000 h⁻

1.

13. A pre-processing assembly according to claim 12, wherein the space velocity of said fuel feedstock in said deoxidizer bed is between 5,000 and 12,000 h⁻

1.

14. A pre-processing assembly according to claim 13, wherein:

said deoxidizer bed has a volume of 0.7 cubic feet; and

said pre-reforming bed has a volume of 2.5 cubic feet.

15. A pre-processing assembly according to claim 14, wherein the temperature of said fuel feedstock upon entry into said assembly is approximately 375°

C.

16. A pre-processing assembly according to claim 15, wherein the deoxidizer bed operates at temperatures between 300°

C. and 600°

C., and said pre-reforming bed operates at temperatures between 320°

C. and 540°

C.

17. A pre-processing assembly according to claim 16, wherein the steam to carbon ratio of the fuel feedstock is between 2.9 and 3.4.

18. A pre-processing assembly according to claim 17, wherein the superficial velocity of the fuel feedstock in said pre-reforming bed is 1.3 ft/s at STP conditions.

19. A pre-processing assembly in accordance with claim 1, wherein said pre-reforming unit is further adapted to remove sulfur-containing compounds from said fuel feedstock.

67. A pre-processing assembly according to claim 1, wherein said fuel feedstock is a multi fuel such as natural gas, peak shaving gas, coal bed methane, digester gas, propane, LPG, and HD-5.

20. A pre-processing assembly for processing fuel feedstock for a fuel cell, the fuel feedstock including oxygen and hydrocarbons having higher and lower hydrocarbon content, said pre-processing assembly comprising:

a deoxidizing unit for reducing the oxygen in said fuel feedstock;

a propane processor unit for reducing the propylene in said fuel feedstock; and

a pre-reforming unit for reducing the higher hydrocarbon content in said fuel feedstock.

21. A pre-processing assembly according to claim 20, wherein said propane processor unit comprises a nickel-based carbon resistant catalyst.

22. A pre-processing assembly according to claim 21, wherein said deoxidizing unit, said propane processor unit and said pre-reforming unit are disposed within a common vessel.

23. A pre-processing assembly according to claim 22, wherein said deoxidizing unit comprises a deoxidizing bed, said pre-reforming unit comprises a pre-reforming bed and said propane processor unit comprises a propane processor bed.

24. A pre-processing assembly according to claim 23, wherein said deoxidizing bed, said propane processor bed and said pre-reforming bed are disposed within said common vessel such that said fuel feedstock passes through said deoxidizing bed first, then through one of said propane processor bed and said pre-reforming bed, and thereafter through the other of said propane processor bed and said pre-reforming bed.

25. A pre-processing assembly according to claim 24, wherein said deoxidizing bed, said propane processor bed and said pre-reforming bed are disposed within said common vessel such that said fuel feedstock passes through said deoxidizing bed first, then through said propane processor bed, and thereafter through said pre-reforming bed.

26. A pre-processing assembly according to claim 24, wherein said deoxidizing bed comprises a deoxidizing catalyst and said pre-reforming bed comprises a pre-reforming catalyst.

27. A pre-processing assembly according to claim 26, wherein said deoxidizing catalyst is one of Pt—

Pd on alumina catalyst, Pt—

Rh-based catalyst and Rh—

Pd-based alumina catalyst.

28. A pre-processing assembly according to claim 27, wherein said deoxidizing catalyst is G-74D.

29. A pre-processing assembly according to claim 27, wherein said pre-reforming catalyst is a nickel based catalyst.

30. A pre-processing assembly according to claim 29, wherein said pre-reforming catalyst is one of C11-PR, CRG-F, CRG-LH and G-180.

31. A pre-processing assembly according to claim 30, wherein said carbon resistant catalyst is FCR-HC59.

32. A pre-processing assembly according to claim 31, wherein:

said deoxidizing bed has a volume of 0.7 cubic feet;

said propane processor bed has a volume of 0.75 cubic feet;

said pre-reforming bed has a volume of 1.7 cubic feet.

33. A pre-processing assembly according to claim 32, wherein:

the space velocity of said fuel feedstock in said deoxidizing bed is between 5,000 and 10,000 h<sup>−

1</sup>;

the space velocity of said fuel feedstock in said propane processor bed is between 1900 and 10,000 h<sup>−

1</sup>; and

the space velocity of said fuel feedstock in said pre-reforming processor bed is between 2,000 and 5,000 h<sup>−

1</sup>.

34. A pre-processing assembly according to claim 33, wherein the fuel inlet temperature is between 300 and 450°

C.

35. A pre-processing assembly according to claim 34, wherein said deoxidizer bed is adapted to operate at a temperature between 300°

C. and 600°

C., said propane processor bed is adapted to operate at a temperature between 300°

C. and 540°

C., and said pre-reforming bed is adapted to operate at temperature between 300°

C. and 540°

C.

36. A pre-processing assembly according to claim 35, wherein the steam to carbon ratio in said fuel feedstock is between 2.9 and 3.4.

37. A pre-processing assembly according to claim 20, wherein said pre-reforming unit is further adapted to remove sulfur-containing compounds from said fuel feedstock.

45. A fuel processing method according to claim 34, wherein said propane processor unit is disposed in said common vessel and comprises a propane processing bed.

46. A fuel processing method according to claim 45, wherein said deoxidizer bed, said pre-reforming bed and said propane processing bed are disposed in said common vessel such that said fuel feedstock flows first through said deoxidizing bed, and then through one of said propane processing bed and said pre-reforming bed, and thereafter through the other of said propane processing bed and said pre-reforming bed.

47. A fuel processing method according to claim 46, wherein said propane processing bed comprises a nickel-based carbon resistant catalyst.

68. A pre-processing assembly according to claim 20, wherein said assembly is adapted to process natural gas, HD-5 and LPG hydrocarbon fuel feedstocks to produce methane rich gas for use in a high temperature fuel cell.

38. A fuel processing method for processing fuel feedstock for a fuel cell, the fuel feedstock including oxygen and hydrocarbons having higher and lower hydrocarbon content, the fuel processing method comprising the steps of:

providing said fuel feedstock;

reducing oxygen in said fuel feedstock using a deoxidizing unit;

reducing said higher hydrocarbon content in said fuel feedstock using a pre-reforming unit;

wherein said deoxidizing unit and said pre-reforming unit are disposed within a common vessel such that said fuel feedstock first flows through said deoxidizing unit and thereafter through said pre-reforming unit.

39. A fuel processing method according to claim 38, wherein said deoxidizing unit comprises a deoxidizing bed and said pre-reforming unit comprises a pre-reforming bed, said pre-reforming bed following said deoxidizing bed along the flow path of said fuel feedstock.

40. A fuel processing method according to claim 39, wherein said deoxidizing bed comprises a deoxidizing catalyst and said pre-reforming bed comprises a pre-reforming catalyst.

41. A fuel processing method according to claim 40, wherein said deoxidizing catalyst is one of Pt—

Pd on alumina catalyst, Pt—

Rh-based catalyst and Rh—

Pd-based alumina catalyst, and wherein said pre-reforming catalyst is a nickel-based catalyst.

42. A fuel processing method according to claim 41, wherein said deoxidizing catalyst is G-74D.

43. A fuel processing method according to claim 41, wherein said pre-reforming catalyst is one of C11-PR, CRG-F, CRG-LH and G-180.

44. A fuel processing method according to claim 39, further comprising a step of reducing the propylene in said fuel feedstock using a propane processor unit.

48. A fuel processing method according to claim 43, wherein said carbon resistant catalyst is FCR-HC59.

49. A fuel processing method according to claim 38, wherein reducing said oxygen in said deoxidizing bed produces hydrogen, and said lower hydrocarbon content is converted to produce hydrogen in said pre-reforming bed.

50. A fuel processing method according to claim 49, wherein the space velocity of said fuel feedstock in said pre-reforming bed is such that hydrogen back diffusion is developed and maintained in said pre-reforming bed.

51. A fuel processing method according to claim 38, further comprising removing sulfur-containing compounds from said fuel feedstock in said pre-reforming unit.

52. A fuel cell system for use with a fuel feedstock, said fuel feedstock including oxygen and hydrocarbons having higher and lower hydrocarbon content, said fuel cell system comprising:

pre-processing assembly for processing said fuel feedstock comprising;

a deoxidizing unit for reducing the oxygen in said fuel feedstock;

a pre-reforming unit for reducing the higher hydrocarbon content in said fuel feedstock; and

a common vessel;

wherein said deoxidizing unit and said pre-reforming unit are disposed within said common vessel such that said fuel feedstock passes through said deoxidizing unit first and thereafter through said pre-reforming unit; and

a fuel cell for receiving said fuel feedstock after passage through said pre-processing assembly.

53. A fuel cell system according to claim 52, wherein said pre-processing assembly further comprises a propane processor unit for processing propane and propylene in said fuel, said propane processor unit being disposed in said common reaction vessel.

54. A fuel cell system according to claim 53, wherein said deoxidizing unit comprises a deoxidizing bed, said pre-reforming unit comprises a pre-reforming bed and said propane processor unit comprises a propane processor bed.

55. A fuel cell system according to claim 54, wherein:

said deoxidizing bed, said propane processor bed and said pre-reforming bed are disposed within a common vessel such that said fuel feedstock passes through said deoxidizing bed first, then through one of said propane processor bed and said pre-reforming bed, and thereafter through the other of said propane processor bed and said pre-reforming bed.

56. A fuel cell system according to claim 55, further comprising:

a preheater for preheating said fuel feedstock before said fuel feedstock is processed by said pre-processing assembly.

57. A fuel cell system according to claim 56, further comprising:

a desulfurizer for reducing the sulfur content in said fuel feedstock before said fuel feedstock is processed by said pre-processing assembly.

58. A fuel cell system according to claim 57, wherein said desulfurizer precedes said preheater.

59. A fuel cell system in accordance with claim 56, wherein said preheater heats said fuel feedstock to approximately 375°

C.

60. A fuel cell system in accordance with claim 54, wherein:

said deoxidizer bed comprises one of Pt—

Pd on alumina catalyst, Pt—

Rh-based catalyst and Rh—

Pd-based alumina catalyst;

said pre-reforming bed comprises a nickel based catalyst; and

said propane processor bed comprises a nickel-based carbon resistant catalyst.

61. A fuel cell system in accordance with claim 60, wherein said nickel-based carbon resistant catalyst is doped with promoters comprising at least one of cerium oxide, lanthanum oxide, palladium and platinum.

62. A fuel cell system in accordance with claim 61, wherein:

deoxidizing bed comprises a G-74D catalyst;

said pre-reforming bed comprises one of C11-PR, CRG-F, CRG-LH and G-180; and

said propane processor bed comprises FCR-HC59 catalyst.

63. A fuel cell system according to claim 52, wherein said deoxidizing unit in reducing said oxygen produces hydrogen and said pre-reforming unit converts a portion of said lower hydrocarbon content to hydrogen to maintain a reducing environment in said pre-reforming unit.

64. A fuel cell system according to claim 63, wherein the space velocity of the fuel feedstock in said pre-reforming unit is such that hydrogen back diffusion is developed and maintained in said pre-reforming unit.

65. A fuel cell system according to claim 52, wherein said pre-reforming unit is further adapted to remove sulfur-containing compounds from said fuel feedstock.

66. A fuel cell system according to claim 52, wherein said fuel cell is one of a molten carbonate fuel cell and solid oxide fuel cell.