FUEL CELL POWER GENERATION SYSTEM AND ITS OPERATION METHOD

PROBLEM TO BE SOLVED: To provide a fuel cell power generation system which has no radiator and no process burner capable of continuously operating a fuel cell even if power demand and heat demand are imbalanced, and to provide its operation method. SOLUTION: The fuel cell power generation system 1 controls heat storage amount by stages by changing an exhaust heat recovering circulation system when a hot water storage tank 11 reaches the specified temperature (hot water temperature of 80 °C). A first stage: a change-over valve V1 is closed, a switch-over valve V2 is opened, and a passage bypassing a hear exchanger 10 is used. Since the exhaust heat recovering amount is decreased by the heat exchange amount of the heat exchanger 10, hot water temperature rising speed inside the hot water storage tank 11 can be suppressed, the exhaust heat amount not recovered with the heat exchanger 10 is exhausted to the atmosphere through an exhaust gas line E1 as exhaust gas in which temperature is raised by heat equivalent to nonrecovered enthalpy. A second stage; in the case where the hot water temperature in the hot water storage tank 11 is further raised, bypass technique is applied to a heat exchanger 15, and exhaust heat recovery amount is further decreased. COPYRIGHT: (C)2005,JPO&NCIPI