Method and arrangement for utilizing recirculation for high temperature fuel cell system

An arrangement utilizing recirculation for a high temperature fuel cell system, each fuel cell in the fuel cell system having an anode side, a cathode side, and an electrolyte between the anode side and the cathode side, the fuel cell system comprising:

• a feedback arrangement for performing anode side recirculation flow of reactants;
• an anode recycle blower for accomplishing a recycle ratio of about 70% or more for a recirculation flow volume;
• a first pipe arrangement for feeding to the recirculation flow, a feed-in flow having an oxygen content, the feed-in flow being about 30% or less of an entire flow volume;
• a heat exchanger for performing heat exchanging to reduce temperature conditions in the recirculation flow;
• a reformer for performing catalytic partial oxidation in the recirculation flow to produce an high amount of hydrogen for the recirculation flow in fuel cell system start-up or shutdown situations;
• and
• a second pipe arrangement for exhausting about 30% or less of the entire flow volume from the anode side recirculation, and wherein the feedback arrangement and the anode recycle blower are configured to provide an inlet temperature of about 350° C. to 500° C. to the reformer and an outlet temperature of the reformer which does not exceed about 800° C.

A method utilizing recirculation for a high temperature fuel cell system, which method performs anode side recirculation flow of reactants, and accomplishes a recycle ratio about 70% or more for a recirculation flow volume, the method comprising:

• feeding to the recirculation flow volume a feed-in flow, which includes an oxygen content, the feed-in flow being about 30% or less of an entire flow volume;
• performing heat exchanging to provide substantially reduced temperature conditions in the recirculation flow;
• performing catalytic partial oxidation in the recirculation flow to produce an amount of hydrogen for the recirculation flow in fuel cell system during start-up or shutdown situations;
• and
• exhausting about 30% or less of the entire flow volume from the anode side recirculation, wherein the heat exchanging provides an inlet temperature of about 350° C. to about 500° C. to the catalytic partial oxidation and an outlet temperature which does not exceed about 800° C.