Solid oxide fuel cell system

A solid oxide fuel cell system in which electrical power is produced by reacting fuel and oxidant gas for electrical generation, comprising:

• a fuel cell module equipped with a fuel cell stack;
• a reformer, disposed inside the fuel cell module, that produces hydrogen by performing a POX step, an ATR step, and an SR step, wherein in the POX step a reforming reaction for partial oxidation reforming of fuel is performed by chemically reacting the fuel with oxidant gas, in the ATR step a reforming reaction for auto-thermal reforming of fuel is performed by simultaneously bringing about the partial oxidant reforming reaction and a steam reforming reaction in which fuel and steam are chemically reacted, and in the SR step a reforming reaction is performed by the steam reforming only;
• a combustion chamber, disposed inside the fuel cell module, wherein fuel which has passed through the reformer and the fiael cell stack is combusted to heat the reformer;
• a fuel supply apparatus that feeds fuel reformed by the reformer to the fuel cell stack by supplying fuel to the reformer;
• a reforming oxidant gas supply apparatus that supplies reforming oxidant gas to the reformer;
• a water supply apparatus that supplies reforming water to the reformer;
• an electrical generating oxidant gas supply apparatus that supplies electrical generating oxidant gas for electrical generation to the fuel cell stack;
• and
• a control device that controls the fuel supply apparatus, the reforming oxygen gas supply apparatus, the water supply apparatus, and the electrical generating oxidant gas supply apparatus based on the temperature in the fuel cell module so that the POX step, the ATR step, and the SR step are executed in predetermined respective temperature bands in sequence inside the reformer, to raise the temperature of the fuel cell stack to the temperature at which electrical generation is possible;
• wherein the control device includes a localized temperature rise suppression circuit that suppressed localized temperature rises in the reformer by inducing steam reforming in parts within the reformer when there are localized excessive temperature rises during the POX step.