Patent ID: 8507136

Claim:
A fuel cell system comprising: a reforming unit configured to subject a mixed gas containing a raw gas and steam to a reforming reaction by a reforming catalyst, thereby generating a reformed gas containing hydrogen; a carbon monoxide decreasing unit configured to allow the reformed gas generated by the reforming unit to contact a carbon monoxide decreasing catalyst, thereby decreasing carbon monoxide contained in the reformed gas; a fuel cell coupled to the carbon monoxide decreasing unit by a raw gas channel and configured to generate electric power by hydrogen contained in the reformed gas passed through the carbon monoxide decreasing unit and; a burner unit configured to burn at least one of an off-gas containing hydrogen not consumed in the fuel cell, the raw gas and the reformed gas using combustion air supplied by an air blower; and a raw gas supply device configured to supply the raw gas to the reforming unit and to the burner unit directly or through the reforming unit, a controller in communication with the raw gas supply device and the air blower, the controller executes a stored startup control program and controls the raw gas supply device and the air blower to set a ratio between a total amount and an amount of combustion air delivered to the burner unit by the air blower and to adjust the ratio to a predetermined ratio at the start-up operation of the fuel cell system, where the total amount is a sum of an amount of raw gas supplied by the raw gas supply device and burnt in the burner unit and an amount of a desorbed raw gas desorbed out of components of the raw gas adsorbed by at least one of the reforming catalyst and the carbon monoxide decreasing catalyst.