Patent ID: 8841039

Claim:
A method of operating an indirect internal reforming solid oxide fuel cell system comprising: providing the indirect internal reforming solid oxide fuel cell system, the system comprising: an indirect internal reforming solid oxide fuel cell comprising: an internal reformer for producing a reformed gas from a hydrocarbon-based fuel by using a steam reforming reaction, a solid oxide fuel cell for generating electric power by using the reformed gas obtained in the internal reformer, and a container for containing the internal reformer and the solid oxide fuel cell, the internal reformer being disposed in a position to receive heat radiation from the solid oxide fuel cell; an external reformer for producing a reformed gas by reforming a hydrocarbon-based fuel, the external reformer being disposed outside the container; and a line for leading the reformed gas obtained in the external reformer from the external reformer to an anode of the solid oxide fuel cell, wherein the internal reformer is connected to the solid oxide fuel cell not via the external reformer, and the external reformer is connected to the solid oxide fuel cell not via the internal reformer; feeding the reformed gas produced by the external reformer to the anode of the solid oxide fuel cell only when starting up and shutting down the system; feeding the reformed gas produced by the internal reformer to the anode of the solid oxide fuel cell only when a temperature of the internal reformer is a temperature at which reforming is possible in the internal reformer.