Patent ID: 7425380

Claim:
A fuel cell system comprising: a fuel gas supply unit supplying fuel gas; an oxidant gas supply unit supplying oxidant gas; a fuel cell stack generating electric power using the fuel gas and the oxidant gas; an anode off-gas recirculation unit directly recirculating anode off-gas, discharged from an anode of the fuel cell stack, to the anode; a purging unit temporarily discharging the anode off-gas from the anode off-gas recirculation unit to an outside thereof; a combustor combusting at least the anode off-gas, discharged from the purging unit, and the oxidant gas or cathode off-gas discharged from a cathode of the fuel cell stack; and a system controller operative to permit the purging unit to discharge the anode off-gas to the combustor, such that a combustion temperature of the combustor is equal to or less than a given temperature.