Catalytic combustors keeping contained medium warm in response to hydrostatic valve

• US 7,771,663 B2
• Filed: 10/31/2005
• Issued: 08/10/2010
• Est. Priority Date: 12/29/2004
• Status: Active Grant

• Current Assignee: Audi AG (Volkswagen AG)
• Original Assignee: UTC Power Corporation (Rtx Corporation)
• Inventors: Resnick, Gennady, Cameron, James, Reiser, Carl A., Saito, Kazuo
• Primary Examiner(s): BHAT, NINA NMN
• Application Number:
  US11/794,599
• Publication Number:
  US 20090280036A1
• Time in Patent Office: 1,744 Days
• Field of Search: 422/105, 422/107, 422/190, 429/22, 429/24, 431/268, 431/328, 431/329
• US Class Current: 422/105
• CPC Class Codes: F23C 13/00 Apparatus in which combustion takes place in the presence of catalytic material in a fluidised bed of catalytic particles F23C10/01; radiant gas burners using catalysis for flameless combustion F23D14/18
• CPC Class Codes: F23C 13/08 characterised by the catalytic material
• CPC Class Codes: F23C 2900/9901 Combustion process using hydrogen, hydrogen peroxide water or brown gas as fuel
• CPC Class Codes: F23D 14/22 with separate air and gas feed ducts, e.g. with ducts running parallel or crossing each other
• CPC Class Codes: F23D 14/32 using a mixture of gaseous fuel and pure oxygen or oxygen-enriched air F23D14/38 takes precedence
• CPC Class Codes: F23N 2225/18 feedwater temperature
• CPC Class Codes: F23N 2237/12 catalytic burners
• CPC Class Codes: H01M 8/04022 Heating by combustion
• CPC Class Codes: H01M 8/04126 Humidifying
• CPC Class Codes: H01M 8/2475 Enclosures, casings or containers of fuel cell stacks
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

Water in a fuel cell accumulator is kept above freezing by a hydrogen/oxygen catalytic combustor fed hydrogen through a mechanical thermostatic valve in thermal communication with the container and connected to a hydrogen supply. The system includes an ejector hydrogen/oxygen combustor and a diffusion hydrogen/oxygen combustor for warming a medium within a container such as water in the accumulator of a fuel cell in response to a mechanic hydrostatic valve which conducts hydrogen to a combustor responsive to the temperature of the container.

Claims

1. A system for keeping a medium (9) in a container (10) warm, comprising:

a container (10) having a heatable surface (11) through which heat may be conducted into a medium (9) within the container; and

a supply (28) of hydrogen;

characterized by;

a first valve operable to be closed unless the time period of a related timer has expired after said first valve has been armed to become open;

a second valve (25) having a temperature responsive member (26) disposed in proximity with said container and responsive to either (i) the temperature of the container or (ii) the ambient temperature surrounding the container, said second valve operable to open in response to said temperature responsive member being below a first temperature and to close in response to said temperature responsive member being above a second temperature, said second temperature being not lower than said first temperature, said valves serially connected to said supply to provide, when said valves are both open, a source (24) of hydrogen for combustion to heat said heatable surface; and

a hydrogen/oxygen catalytic combustor (13) selected from

(a) an ejector combustor (13a) comprising—

a heating surface (36), through which heat is to be conducted to a heat utilizing apparatus;

an ejector (32) having an outlet, a primary inlet (31) in fluid communication with said source of hydrogen, and a secondary inlet (33) in fluid communication with air;

and a hydrogen/oxygen combustion catalyst (34) disposed between said ejector outlet and said heating surface; and

(b) a diffusion combustor (13b) comprising;

a hydrogen/oxygen combustion catalyst (38) having first and second sides;

a heating surface (12), through which heat is to be conducted to a heat utilizing apparatus, separated from said first side of said catalyst by a first space (39);

a hydrogen conduit (43) for conducting hydrogen from said source to said first space; and

a diffusion control device (40) disposed in air and separated from said second side of said catalyst by a second space (41);

said heatable surface in contact with one of said heating surfaces, whereby hydrogen passing through said valves is catalytically combusted to heat the medium within said container.

2. A system according to claim 1 wherein:

said container (10) is an accumulator of a fuel cell power plant.

3. A system according to claim 1 wherein:

said first valve is a timer-operated valve.

4. A system according to claim 1 wherein:

said second valve is a thermostatic valve.

5. A temperature-responsive hydrogen source for a keep-warm system, comprising:

a container (10) having a heatable surface (11) through which heat may be conducted into said container; and

a supply (28) of hydrogen;

characterized by;

a valve (25) having a temperature responsive member (26) in proximity with said container and responsive to either (i) the temperature of the container or (ii) the ambient temperature surrounding the container, said valve operable to open in response to said temperature responsive member being below a first temperature and to close in response to said temperature responsive member being above a second temperature, said second temperature being not lower than said first temperature, said valve connected to said supply to provide, when said valve is open, a source (24) of hydrogen for combustion to heat said heatable surface.

6. A freeze-proof container characterized by:

a source according to claim 5; and

a hydrogen/oxygen catalytic combustor (13) for combusting hydrogen from said source (24) to heat said heatable surface (11).

7. A container according to claim 6 wherein:

said valve (25) is in thermal contact (26) with said container (10).

8. An accumulator for a fuel cell power plant characterized by:

a container according to claim 6.

9. A hydrogen/oxygen catalytic combustor (13a) characterized by:

a heating surface (36), through which heat is to be conducted to a heat utilizing apparatus (10);

an ejector (32) having an outlet, a primary inlet (31) in fluid communication with a source (24) of hydrogen, and a secondary inlet (33) in fluid communication with air; and

a hydrogen/oxygen combustion catalyst (34) disposed between said ejector outlet and said heating surface.

10. A hydrogen/oxygen catalytic combustor (13b), characterized by:

a hydrogen/oxygen combustion catalyst (38) having first and second sides;

a hydrogen conduit (43) for conducting hydrogen from a source (24) to said first side; and

a diffusion control device (40) disposed in air and separated from said second side of said catalyst by a second space (41).

11. A combustor according to either of claim 9 or 10 wherein said catalyst comprises:

a coating of catalyst material on a porous metal substrate.

12. A combustor according to either of claim 9 or 10 wherein said catalyst comprises:

a mixture of catalyst material and hydrophobic material on a porous substrate.

13. A combustor according to either of claim 9 or 10 wherein said catalyst (38) comprises:

a porous metal substrate (130), the interior surfaces of which are washcoated with a mixture of polytetrafluoroethylene and a noble metal or alloys thereof.

14. A combustor according to claim 13 wherein:

said noble metal is selected from platinum, palladium and alloys of platinum and/or palladium.

15. A combustor according to claim 10 further comprising:

an insulator (44) surrounding said catalyst, said first space and said second space; and

wherein;

said diffusion control device (40) extends beyond said second space (41) to substantially the outer periphery of said insulator.

16. A combustor according to claim 10 wherein:

said first space (39) includes a metal screen (124).

17. A combustor according to claim 10 wherein:

said first space (39) contains a second surface (156) upon which moisture generated by combustion in said catalyst (38) condenses; and

further characterized by;

a hydrophilic mesh (126, 127) having pores of a first size disposed below said second surface; and

a wicking material (133, 140, 147) having pores of a second size smaller than said first size extending from said mesh to a point below said diffusion control plate (40, 110).

18. A combustor according to claim 17 further characterized by:

a chamber (190) disposed below said diffusion control plate and adapted to receive said condensate, said chamber containing a substance (192) which with said condensate forms a liquid which has a freezing temperature below −

50°

C. (−

60°

F.).

19. A combustor according to claim 18 wherein said substance is CaCl₂ salt.

20. A combustor according to claim 17, further characterized by:

a porous hydrophilic mixer (200) disposed below said diffusion control device (40) to receive said condensate;

a source (206) of antifreeze miscible with water; and

at least one capillary tube (205) interconnecting said source of antifreeze with said porous hydrophilic mixer, whereby said condensate mixes with antifreeze and the antifreeze mixture drips into ambient from said porous hydrophilic mixer.

21. A combustor according to claim 20 wherein said antifreeze is windshield washer fluid.

22. A combustor according to claim 17 wherein:

said condensate is conducted to ambient.

23. A combustor according to claim 10 wherein;

said catalyst (38, 130) is a porous cylinder having a central bore disposed with its axis vertical.

24. A combustor according to claim 23 wherein:

a hydrogen conduit (112, 103) passes through said central bore to provide hydrogen to said first space.

25. A combustor according to claim 23 wherein:

said first space (39) contains a second surface (156) upon which moisture generated by combustion in said catalyst (38) condenses; and

further characterized by;

a hydrophilic mesh (126, 127) having pores of a first size disposed below said second surface; and

a wicking material (133, 140, 147) having pores of a second size smaller than said first size extending through said central bore from said mesh to a point below said diffusion control device (40, 110).

26. A combustor according to claim 10 wherein:

said diffusion control device (40) limits the amount of oxygen diffused therethrough to thereby limit the temperature of said catalyst.

27. A combustor according to claim 10 wherein:

said catalyst comprises a porous cylinder, the interior of which comprises said first side and the exterior of which comprises said second side; and

said diffusion control device (40) comprises a cylinder surrounding said catalyst and spaced therefrom, and having oxygen diffusion holes (225) therein.