Method for generating a gas which may be used for startup and shutdown of a fuel cell

1. A method for generating a reducing gas having a variable combustibles content, comprising:

providing a nitrogen-rich oxidant stream, the oxidant stream having a nitrogen content greater than that of ambient air, the oxidant stream also having an oxygen (O 2 ) content;

providing a hydrocarbon fuel stream;

combining the hydrocarbon fuel stream and the oxidant stream into a feed mixture, the feed mixture having an oxidant/fuel ratio;

reacting the feed mixture in a catalytic reactor to generate the reducing gas; and

controlling both the O 2 content of the oxidant stream and the oxidant/fuel ratio of the feed mixture to maintain a predetermined control temperature while also independently varying both the O 2 content of the oxidant stream and the oxidant/fuel ratio of the feed mixture to obtain a selected combustibles content of the reducing gas.

2. The method of claim 1 , further comprising supplying the reducing gas to a fuel cell.

3. The method of claim 1 , further comprising: generating a nitrogen-rich stream; and combining the nitrogen-rich stream with air to yield the nitrogen-rich oxidant stream.

4. The method of claim 1 , wherein the nitrogen-rich oxidant stream is generated by extracting nitrogen from air using a nitrogen separation membrane.

5. The method of claim 1 , wherein the predetermined temperature is a predetermined temperature of the reducing gas.

6. The method of claim 1 , wherein the predetermined temperature is a predetermined temperature of a catalyst of the catalytic reactor.

7. The method of claim 1 , further comprising:

providing feedback information pertaining to at least two of the O 2 content, the temperature of the reducing gas and at least one of a hydrogen (H 2 ) content of the reducing gas and a carbon monoxide (CO) content of the reducing gas,

wherein said controlling both the O 2 content of the oxidant stream and the oxidant/fuel ratio of the feed mixture to maintain the predetermined temperature is performed based on the feedback information.

8. A method for generating a reducing gas and using the reducing gas in a fuel cell, comprising:

a step for providing an oxidant stream;

a step for supplying a hydrocarbon fuel;

a step for combining the oxidant and said hydrocarbon fuel into a feed mixture, the feed mixture having an oxidant/fuel ratio;

a step for catalytically converting the feed mixture to generate a reducing gas;

a step for controlling both the O 2 content of the oxidant stream and the oxidant/fuel ratio of the feed mixture to maintain a predetermined temperature of the reducing gas while also independently varying at least one of the O 2 content of the oxidant stream and the oxidant/fuel ratio of the feed mixture to obtain a selected combustibles content of the reducing gas; and

a step for directing the reducing gas to the fuel cell.

9. A method for generating a reducing gas having a variable combustibles content, comprising:

providing a nitrogen-rich oxidant stream, the oxidant stream having a nitrogen content greater than that of ambient air, the oxidant stream also having an oxygen (O 2 ) content, wherein the nitrogen-rich oxidant stream is generated by extracting nitrogen from air using a nitrogen separation membrane;

providing a hydrocarbon fuel stream;

combining the hydrocarbon fuel stream and the oxidant stream into a feed mixture, the feed mixture having an oxidant/fuel ratio;

reacting the feed mixture in a catalytic reactor to generate the reducing gas; and

controlling both the O 2 content of the oxidant stream and the oxidant/fuel ratio of the feed mixture to maintain a predetermined control temperature while also independently varying both the O 2 content of the oxidant stream and the oxidant/fuel ratio of the feed mixture to obtain a selected combustibles content of the reducing gas.