Patent ID: 7862937

Claim:
An anode effluent control method for a fuel cell power plant comprising a fuel cell stack which performs power generation using anode gas having hydrogen as a main component, the anode gas being discharged from the fuel cell stack as anode effluent following a power generation reaction, a return passage which re-circulates the anode effluent into the anode gas, and a purge valve which discharges the anode effluent in the return passage to the outside of the passage, the control method comprising: calculating a first energy loss caused by an increase in a non-hydrogen component in the anode gas while the purge valve is closed; calculating a second energy loss which corresponds to an amount of hydrogen lost from the anode gas when the purge valve is opened; maintaining the purge valve in a closed state when the second energy loss is larger than the first energy loss; and opening the purge valve when the second energy loss equals or falls below the first energy loss.