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1. WO2011029024 - APPARATUS FOR GENERATING A GAS WHICH MAY BE USED FOR STARTUP AND SHUTDOWN OF A FUEL CELL

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[ EN ]

Claims

What is claimed is:

1 . A reducing gas generator for startup and shutdown of a fuel cell, comprising:

an oxidant source structured to supply a low oxygen (O2) content oxidant, the low O2 content oxidant having an O2 content less than that of atmospheric air; a fuel input configured to receive a hydrocarbon fuel;

a merging chamber in fluid communication with said oxidant source and in fluid communication with said fuel inlet, said merging chamber structured to receive the hydrocarbon fuel and the low oxygen (O2) content oxidant and to discharge a feed mixture containing both the hydrocarbon fuel and the low oxygen (O2) content oxidant;

a catalytic reactor in fluid communication with said merging chamber, said catalytic reactor structured to receive the feed mixture and to catalytically convert the feed mixture into a reducing gas; and

a reducing gas output fluidly coupled to said catalytic reactor and in fluid communication with at least one of an anode and a reformer of the fuel cell, said reducing gas output operative to direct the reducing gas to said at least one of the anode and the reformer of the fuel cell.

2. The reducing gas generator of claim 1 , further comprising a nitrogen generator operable to extract oxygen (O2) from air and to discharge the balance in the form of a nitrogen-rich gas, the nitrogen-rich gas forming at least a part of the low O2 content oxidant.

3. The reducing gas generator of claim 2, further comprising an air charging system coupled to said nitrogen generator output, said air charging system structured to variably add air to the nitrogen-rich gas to vary the O2 content of the low O2 content oxidant.

4. The reducing gas generator of claim 2, further including a valve structured to add a controlled amount of air to one of the nitrogen-rich gas and the feed mixture.

5. The reducing gas generator of claim 4, wherein said nitrogen generator includes a nitrogen separation membrane configured to separate nitrogen out of air.

6. The reducing gas generator of claim 1 , further including a control system configured to execute program instructions to regulate a control temperature by varying both the O2 content of the low O2 content oxidant and the oxidant/fuel ratio of the feed mixture.

7. The reducing gas generator of claim 6, further comprising a control temperature sensor and an O2 sensor communicatively coupled to said control system.

8. The reducing gas generator of claim 6, further comprising:

an oxidant control valve communicatively coupled to said control system, said oxidant control valve structured to control a flow of the oxidant as directed by said control system; and

a fuel control valve communicatively coupled to said control system, said fuel control valve structured to control a flow of the hydrocarbon fuel as directed by said control system,

wherein said control system is configured to execute program instructions to vary the oxidant/fuel ratio by controlling the output of at least one of said fuel control valve and said oxidant control valve.

9. The reducing gas generator of claim 1 , further including a control system configured to execute program instructions to selectively vary a combustibles content of the reducing gas while maintaining a selected temperature of the reducing gas by varying both the O2 content of the oxidant and the oxidant/fuel ratio of the feed mixture.

10. The reducing gas generator of claim 9, further comprising at least two of a control temperature sensor, an oxygen sensor and a reducing gas combustibles detection sensor communicatively coupled to said control system.

1 1 . The reducing gas generator of claim 1 , further comprising a heat exchanger fluidly coupled downstream of said catalytic reactor, said heat exchanger configured to control a temperature of said reducing gas.

12. The reducing gas generator of claim 1 , further comprising a heater upstream of said catalytic reactor, said heater configured to initiate a catalytic reaction at the catalyst of said catalytic reactor by heating at least a portion of the feed mixture and supplying the heated mixture to said catalytic reactor.

13. The reducing gas generator of claim 12, wherein said heater includes a body configured to continuously maintain a temperature of one of at and above a catalyst light-off temperature of the feed mixture during normal operations of the fuel cell.

14. The reducing gas generator of claim 1 , further comprising at least one of:

a catalyst heater configured to maintain the catalyst of said catalytic reactor at a temperature one of at and above a catalyst light-off temperature of the feed mixture during normal operations of the fuel cell; and

an other heater disposed adjacent the inlet of said catalytic reactor and structured to initiate catalytic reaction of the feed mixture in an upstream portion of said catalytic reactor.

15. The reducing gas generator of claim 1 , further comprising means for varying a combustibles content of the reducing gas while maintaining a constant control temperature.

16. The reducing gas generator of claim 15, wherein the feed mixture includes an oxidant having an O2 content, and wherein said means for varying includes:

means for varying the O2 content in the oxidant; and

means for varying an oxidant/fuel ratio of the feed mixture.

17. A fuel cell system, comprising:

a fuel cell, including an anode, a cathode, an electrolyte coupled to said anode and said cathode, and a reformer; and

a reducing gas generator configured for startup and shutdown of the fuel cell, the reducing gas generator including:

an oxidant source structured to supply a low oxygen (O2) content oxidant stream, the low O2 content oxidant stream having an O2 content less than that of atmospheric air;

a fuel input configured to receive a hydrocarbon fuel;

a merging chamber in fluid communication with said oxidant source and in fluid communication with said fuel inlet, said merging chamber structured to receive the hydrocarbon fuel and the low O2 content oxidant stream and to discharge a feed mixture containing both the hydrocarbon fuel and the low O2 content oxidant stream;

a catalytic reactor in fluid communication with said merging chamber, said catalytic reactor structured to receive said feed mixture and catalytically convert said feed mixture into a reducing gas; and

a reducing gas output fluidly coupled to said catalytic reactor and in fluid communication with at least one of said anode and said reformer, said reducing gas output operative to direct the reducing gas to said at least one of said anode and said reformer.

18. The fuel cell system of claim 17, further comprising:

an air intake,

a nitrogen generator in fluid communication with said air intake, said nitrogen generator having a nitrogen generator output and structured to receive air from said air intake, to extract O2 from the air received from said air intake and to discharge from the nitrogen generator output the balance in the form of a nitrogen-rich gas, the nitrogen-rich gas forming at least a part of the low O2 oxidant stream.

19. A reducing gas generator, comprising:

an oxidant source structured to supply a low-oxygen (O2) content oxidant stream, the low O2 oxidant stream having an O2 content less than that of atmospheric air;

a fuel source fluidly coupled to said oxidant source and structured to supply a hydrocarbon fuel;

a merging chamber fluidly coupled to said fuel source and said oxidant source, said merging chamber structured to combine the oxidant and the hydrocarbon fuel into a feed mixture, the feed mixture having an oxidant/fuel ratio defined by a ratio of the amount of the oxidant in the feed mixture to the amount of the hydrocarbon fuel in the feed mixture;

a catalytic reactor fluidly coupled to said merging chamber and structured to catalytically convert the feed mixture to generate a reducing gas; and

a control system configured to execute program instructions to control the flow rate of feed mixture and both the O2 content of the oxidant stream and the oxidant/fuel ratio of the feed mixture to maintain a predetermined control temperature while varying a combustibles content of the reducing gas output by said catalytic reactor.

20. The reducing gas generator of claim 19, wherein said oxidant source employs a nitrogen generator to supply a nitrogen-rich gas.

21 . The reducing gas generator of claim 20, wherein said nitrogen generator includes a nitrogen separation polymer.

22. The reducing gas generator of claim 19, wherein the reducing gas generator is structured to supply the reducing gas to a fuel cell having at least one of an anode and a reformer, further comprising a reducing gas output fluidly coupled to said catalytic reactor and in fluid communication with at least one of the anode and the reformer, said reducing gas output operative to direct the reducing gas to said at least one of said anode and said reformer.

23. A reducing gas generator, comprising:

means for providing an oxidant stream;

means for supplying a hydrocarbon fuel;

means for combining the oxidant and the hydrocarbon fuel into a feed mixture, the feed mixture having an oxidant/fuel ratio defined by a ratio of the amount of the oxidant in the feed mixture to the amount of the hydrocarbon fuel in the feed mixture;

means for catalytically converting the feed mixture into a reducing gas; and

means for controlling both the O2 content of the oxidant stream and the oxidant/fuel ratio of the feed mixture to selectively vary a combustibles content of the reducing gas while maintaining a selected control temperature.

24. A system for purging a fuel cell, comprising:

an air intake structured to receive atmospheric air;

a compressor fluidly coupled to the air intake, said compressor structured to compress atmospheric air received from the air intake to a pressure above ambient atmospheric pressure; and

a nitrogen generator fluidly coupled to said compressor and fluidly coupled to said fuel cell, said nitrogen generator structured to generate a nitrogen-rich stream from the compressed air and to provide the nitrogen-rich stream to purge at least one component associated with said fuel cell.

25. The system of claim 24, wherein said nitrogen generator includes a nitrogen separation membrane structured to separate oxygen from the

compressed air using the pressure of the compressed air to supply the nitrogen-rich stream.

26. The system of claim 24, further comprising a pressure regulator fluidly coupled between said compressor and said nitrogen generator, said pressure regulator structured to regulate the pressure of the compressed air.

27. A fuel cell system, comprising:

a fuel cell; and

a purging system coupled to said fuel cell, said purging system including: an air intake structured to receive atmospheric air;

a compressor fluidly coupled to the air intake, said compressor structured to compress atmospheric air received from the air intake to a pressure above ambient atmospheric pressure; and

a nitrogen generator fluidly disposed between said compressor and said fuel cell, said nitrogen generator being structured to generate a nitrogen-rich stream from the compressed air and to provide the nitrogen- rich stream to purge at least one component associated with said fuel cell.

28. A control system structured to execute program instructions to control a flow rate of a feed mixture and both the O2 content of an oxidant stream and the oxidant/fuel ratio of the feed mixture to maintain a predetermined control temperature in one of a catalytic reactor and a reducing gas output by said catalytic reactor.

29. The control system of claim 28, wherein said control system is structured to execute program instructions to maintain the predetermined control temperature while varying a combustibles content of the reducing gas output by the catalytic reactor.

30. The control system of claim 28, wherein said control system is structured to execute program instructions to selectively discharge said reducing gas into one or both of an anode of a fuel cell and a reformer of a fuel cell.

31 . The control system of claim 30, wherein the amount of reducing gas discharged to each of said anode and said reformer varies between 0% and 100% of the total amount discharged from said catalytic reactor.