Patent ID: 8501358

Claim:
A solid oxide fuel cell system for generating electricity by reacting fuel and oxidation gas, comprising: a fuel cell module comprising multiple solid oxide fuel cell units; a reformer configured to produce hydrogen through a series of startup operations including a steam reforming reaction (SR) operation, in which fuel is steam reformed by chemically reacting fuel and steam, and an auto thermal reforming reaction (ATR) operation, in which fuel is auto-thermally reformed by simultaneously inducing partial oxidation reforming and steam reforming; a fuel supply device configured to feed the fuel to the reformer and the reformed fuel to the solid oxide fuel cell units; a reforming oxidation gas supply device configured to supply the oxidation gas to the reformer; a steam supply device configured to supply steam to the reformer; an electricity generation oxidation gas supply device configured to supply oxidation gas to the solid oxide fuel cell units to generate electricity; a combustion section placed at one end portion of the solid oxide fuel cell units to combust fuel left unused in electricity generation; and a controller programmed to control the fuel supply device, the reforming oxidation gas supply device, the steam supply device, and the electricity generation oxidation gas supply device, wherein the controller is programmed to effect the startup operations including the ATR and SR operations inside the reformer to heat the solid oxide fuel cell units to an electricity generating startup temperature at which electrical power can be extracted from the fuel cell module, and after the solid oxide fuel cell units are heated above the electricity generating startup temperature and the startup operations end, the controller is further programmed to effect executes an electricity generating operation in which electrical power is extracted from the fuel cell module, and the controller is further programmed to effect a startup electricity generation operation in which a weak electricity is extracted from the fuel cell module to thereby generate heat and raise the temperature of the solid oxide fuel cell units during the startup operations, the weak electricity extracted during the startup electricity generation operation being smaller than the electric power extracted from the fuel cell module during the electricity generating operation.