Integrated fuel reformation and thermal management system for solid oxide fuel cell systems

• US 6,485,852 B1
• Filed: 01/07/2000
• Issued: 11/26/2002
• Est. Priority Date: 01/07/2000
• Status: Expired due to Fees

• Current Assignee: Delphi Technologies, Inc. (Aptiv PLC)
• Original Assignee: Delphi Technologies, Inc. (Aptiv PLC)
• Inventors: Depreter, Bruno, Simpkins, Haskell, Miller, Carl Elmer, Botti, Jean Joseph
• Primary Examiner(s): KALAFUT, STEPHEN J
• Application Number:
  US09/479,165
• Time in Patent Office: 1,054 Days
• Field of Search: 429/17, 429/19, 429/20, 429/26, 422/198, 422/240
• US Class Current: 429/423
• CPC Class Codes: B01J 19/2485 Monolithic reactors
• CPC Class Codes: B01J 2219/00155 using insulating materials or refractories
• 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 2203/0277 containing a catalytic decomposition step
• CPC Class Codes: C01B 2203/0283 containing a CO-shift step, i.e. a water gas shift step
• CPC Class Codes: C01B 2203/066 with fuel cells
• CPC Class Codes: C01B 2203/0805 Methods of heating the process for making hydrogen or synthesis gas
• CPC Class Codes: C01B 2203/0833 Heating by indirect heat exchange with hot fluids, other than combustion gases, product gases or non-combustive exothermic reaction product gases
• CPC Class Codes: C01B 2203/085 by electric heating
• CPC Class Codes: C01B 2203/1247 Higher hydrocarbons
• CPC Class Codes: C01B 2203/1288 Evaporation of one or more of the different feed components
• CPC Class Codes: C01B 2203/148 involving a recycle stream to the feed of the process for making hydrogen or synthesis gas
• CPC Class Codes: C01B 2203/1604 Starting up the process
• CPC Class Codes: C01B 3/384 the catalyst being continuously externally heated
• CPC Class Codes: F28D 9/0018 without any annular circulation of the heat exchange media
• CPC Class Codes: F28D 9/0043 the plates having openings therein for circulation of at least one heat-exchange medium from one conduit to another
• CPC Class Codes: F28F 2270/00 Thermal insulation; Thermal decoupling
• CPC Class Codes: F28F 9/20 Arrangements of heat reflectors, e.g. separately-insertible reflecting walls
• CPC Class Codes: H01M 2004/8684 Negative electrodes
• CPC Class Codes: H01M 2008/1293 : Fuel cells with solid oxide electrolytes
• CPC Class Codes: H01M 8/04007 : related to heat exchange
• CPC Class Codes: H01M 8/04291 : Arrangements for managing water in solid electrolyte fuel cell systems H01M8/04119 takes precedence
• CPC Class Codes: H01M 8/0625 : in a modular combined reactor/fuel cell structure
• CPC Class Codes: H01M 8/0662 : Treatment of gaseous reactants or gaseous residues, e.g. cleaning
• CPC Class Codes: Y02E 60/50 : Fuel cells
• CPC Class Codes: Y02P 20/129 : Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines

Abstract

A compact integrated thermal management and fuel reformation system and method includes a thermally insulated wall forming an envelope having an interior chamber housing, a solid oxide fuel cell stack and a mixed mode heat exchanger. A recuperator having interior walls that are color graded to provide temperature zones effecting a positive temperature gradient in the direction of the solid oxide fuel cell stack is disposed within the chamber and close coupled to the fuel cell stack for absorbing radiation therefrom. The recuperator further heats the partially preheated oxidant gas and partially or fully reforms incoming fuel gas. Manifolds having oxidant and fuel channels for conducting reformed fuel and heated oxidant from the recuperator to fuel cell oxidant and fuel inlets are arranged to maximize fuel flow at the portions of each fuel cell adjacent the recuperator and to maximize oxidant flow near central portions of each fuel cell. A method for providing a tailored anode fuel stream is also provided.

Claims

1. A compact integrated thermal management and fuel reformation system comprising:

a thermally insulated wall forming an envelope having an interior chamber for housing a solid oxide fuel cell stack;

said solid oxide fuel cell stack comprising a plurality of solid oxide fuel cells having oxidant and fuel inlets and arranged to permit fluid flow of incoming oxidant and fuel gases therebetween, and having an exhaust outlet;

a mixed mode heat exchanger disposed within said chamber for partially preheating an oxidant gas, said mixed mode heat exchanger having an oxidant gas inlet in fluid communication with a source of oxidant gas and an oxidant gas outlet;

a recuperator, disposed within said chamber and close coupled to said solid oxide fuel cell stack for absorbing radiation therefrom, for further heating incoming partially preheated oxidant gas and reforming incoming fuel gas,

said recuperator having color graded interior walls providing a plurality of temperature zones and forming a positive temperature gradient in the direction of said solid oxide fuel cell stack,

said recuperator having an oxidant inlet in fluid communication with said oxidant gas outlet of said mixed mode exchanger to receive partially preheated oxidant gas therefrom, an inlet in fluid communication with a fuel source to receive a flow of fuel;

an oxidant outlet, a fuel gas outlet; and

manifolds associated with said solid oxide fuel cell stack and in fluid communication with said oxidant and fuel gas outlets of said recuperator, said manifolds comprising oxidant and fuel channels for conducting fuel and heated oxidant from said recuperator to said solid oxide fuel cell oxidant and fuel inlets.

2. The system of claim 1, wherein said recuperator comprises an extruded monolith having bright white to medium gray to black color grading.

3. The system of claim 1, wherein said recuperator is formed from a ceramic slurry comprising inorganic pigments that are stable to high temperature, oxidizing and reducing environments.

4. The system of claim 1, wherein said manifold channels are arranged so as to maximize fuel flow near peripheral portions of each fuel cell and to maximize oxidant flow near central portions of each fuel cell.

5. The system of claim 1, wherein said manifold channels comprise a ceramic foam tailored to maximize fuel flow near peripheral portions of each fuel cell and to maximize oxidant flow near central portions of each fuel cell.

6. The system of claim 1, wherein said thermally insulated wall, mixed mode heat exchanger, and recuperator are arranged so as to effect a positive temperature gradient in the direction of said solid oxide fuel cell stack.

7. The system of claim 1, comprising ceramic blankets disposed on said recuperator.

8. The system of claim 7, wherein said ceramic blankets comprise cordierite, mullite, silicon carbide, or a combination thereof.

9. The system of claim 1, wherein said envelope is cylindrical.

10. The system of claim 1, wherein said wall and said mixed mode heat exchanger is formed by a super plastic forming process.

11. The system of claim 1, comprising an intumescent polymeric fire shield disposed adjacent said wall.

12. The system of claim 1, further comprising:

a reflective layer provided on an interior wall of said mixed mode heat exchanger.

13. The system of claim 1, wherein said incoming fuel gas comprises solid oxide fuel cell exhaust that is recirculated to said recuperator.

14. The system of claim 1, wherein said solid oxide fuel cell stack further comprises auxiliary cooling ducts.

15. The system of claim 1, further comprising:

an electrically heated gasoline vaporizer, an electrically heated monolith duct for heating oxidant, an oxygen permeable membrane for controlling oxygen partial pressure, or a combination thereof.

16. The system of claim 1, wherein said recuperator further comprises multiple catalyst zones, mixtures of catalysts, or a combination thereof.

17. The system of claim 1, wherein portions of interior surfaces of said wall forming said envelope comprise reflective surfaces.

18. The system of claim 1, wherein said solid oxide fuel cell stack comprises end sections disposed at opposite ends of said stack and a center section disposed between said end sections, and wherein said end sections comprise radiant energy absorbing walls.

19. The system of claim 1, wherein said solid oxide fuel cell stack comprises end sections disposed at opposite ends of said stack and a center section disposed between said end sections, and wherein anodes within said center section comprise a pore structure having a porosity sufficient to optimize removal of H₂O from anode-electrolyte interfaces.

20. A method for providing a tailored anode fuel stream for a solid oxide fuel cell system comprising:

arranging a solid oxide fuel cell stack comprising a plurality of solid oxide fuel cells in fluid communication with a recuperator within an insulated housing, said recuperator having color graded interior walls providing a plurality of temperature zones that form a positive temperature gradient in the direction of said solid oxide fuel cell stack;

introducing a flow of fuel gas into said recuperator;

exposing the recuperator to radiation from said solid oxide fuel cell stack;

exchanging heat from said solid oxide fuel cell stack into the flow of fuel gas;

reforming said fuel gas into a tailored anode fuel stream;

directing said tailored anode fuel stream to anodes of said solid oxide fuel cells.

21. The method of claim 20, wherein said directing is through channels arranged so as to maximize fuel utilization at portions of each fuel cell adjacent said recuperator.

22. The method of claim 20, wherein said method further comprises flowing exhaust from said solid oxide fuel cell stack into said recuperator.

23. The method of claim 20, wherein said fuel gas is gasoline and said reforming is thermal catalytic cracking of said gasoline.

24. The method of claim 23, further comprising:

recirculating cathode exhaust to substantially remove carbon from said recuperator.

25. The method of claim 20, further comprising:

providing multiple catalyst zones, mixtures of catalysts, or a combination thereof, within said temperature zones.

26. The method of claim 20, further comprising:

directing segregated, specialized anode fuel streams into said solid oxide fuel cell stack.

27. The method of claim 20, further comprising:

reforming at least a portion of said fuel gas external to said recuperator.

28. The method of claim 27, further comprising:

reforming at least a portion of said fuel gas within said SOFC stack.

29. The method of claim 20, further comprising:

selecting between endothermic and exothermic reforming to control heat flow into and out of said SOFC stack.

30. A hybrid electric powertrain employing a solid oxide fuel cell system having a compact integrated thermal management and fuel reformation system characterized by:

a thermally insulated wall forming an envelope having an interior chamber for housing a solid oxide fuel cell stack;

said solid oxide fuel cell stack comprising a plurality of solid oxide fuel cells having oxidant and fuel inlets and arranged to permit fluid flow of incoming oxidant and fuel gases therebetween, and having an exhaust outlet;

a mixed mode heat exchanger disposed within said chamber for partially preheating an oxidant gas, said mixed mode heat exchanger having an oxidant gas inlet in fluid communication with a source of oxidant gas and an oxidant gas outlet;

a recuperator, disposed within said chamber and close coupled to said solid oxide fuel cell stack for absorbing radiation therefrom, for further heating incoming partially preheated oxidant gas and reforming incoming fuel gas,

said recuperator having interior walls that are color graded to effect a plurality of temperature zones forming a positive temperature gradient in the direction of said solid oxide fuel cell stack and comprising multiple catalyst zones, mixtures of catalysts, or a combination thereof;

said recuperator having an oxidant inlet in fluid communication with said oxidant gas outlet of said mixed mode exchanger to receive partially preheated oxidant gas therefrom, an inlet in fluid communication with a fuel source to receive a flow of fuel;

an oxidant outlet, a fuel gas outlet; and

manifolds associated with said solid oxide fuel cell stack and in fluid communication with said oxidant and fuel gas outlets of said recuperator, said manifolds comprising oxidant and fuel channels for conducting reformed fuel and heated oxidant from said recuperator to said solid oxide fuel cell oxidant and fuel inlets, wherein said manifold channels are arranged so as to maximize fuel flow near peripheral portions of each fuel cell and to maximize oxidant flow near central portions of each fuel cell.

31. The system of claim 30, wherein said recuperator comprises an extruded monolith formed from a ceramic slurry comprising inorganic pigments that are stable to high temperature, oxidizing and reducing environments.

32. The system of claim 30, comprising an intumescent polymeric fire shield disposed adjacent said wall.

33. The system of claim 30, further comprising an electrically heated gasoline vaporizer, an electrically heated monolith duct for heating oxidant, an oxygen permeable membrane for controlling oxygen partial pressure, or a combination thereof.

34. A reformer comprising:

a recuperator, for heating and reforming incoming fuel gas, having a fuel inlet in fluid communication with a fuel source and an outlet for emitting a stream of reformed fuel;

said recuperator having interior walls that are color graded to effect a plurality of temperature zones forming a positive temperature gradient in the direction of said outlet.

35. The reformer of claim 34, wherein said recuperator comprises an extruded monolith having bright white to medium gray to black color grading.

36. The reformer of claim 34, wherein said recuperator is formed from an extruded ceramic slurry comprising inorganic pigments that are stable to high temperature, oxidizing and reducing environments.

37. The reformer of claim 34, wherein selected portions of said recuperator have ceramic blankets disposed thereon.

38. The reformer of claim 34, wherein said incoming fuel gas comprises solid oxide fuel cell exhaust.

39. The reformer of claim 34, further comprising:

mixtures of catalysts, multiple catalyst zones, or a combination thereof;

wherein said fuel gas inlet is further arranged so as to direct said incoming fuel gas to a selected catalyst zone.

40. The reformer of claim 34, wherein said reformer is arranged so as to produce segregated tailored anode fuel streams.