Patent ID: 8497044

Claim:
A solid oxide fuel cell system for generating electricity by reacting fuel with an electricity generating oxidation gas, comprising: a fuel cell module comprising multiple solid oxide fuel cell units which is thermally prepared for generation of electricity through a series of startup operations comprising an auto-thermal reforming (ATR) reaction operation and a steam reforming (SR) reaction operation performed after the ATR operation; a reformer that supplies reformed fuel to the solid oxide fuel cell units; a fuel supply device that supplies fuel to the reformer for reformation of the fuel; a reforming oxidation gas supply device that supplies reforming oxidation gas to the reformer; a water supply device that supplies water to the reformer; a generating oxidant gas supply device that supplies the electricity generating oxidation gas to the solid oxide fuel cell units; and a controller programmed to control the fuel supply device to reduce a rate of fuel supply to the reformer in a step-wise manner during transitions between adjacent startup operations such that a change in the fuel supply rate which takes place during a transition from the ATR operation to the SR operation is smallest, compared to changes in the fuel supply rate which take place during the other transitions between adjacent startup operations.