Patent ID: 9653742
Date: 2017-05-16
CPC Classifications: H01M,Y02E

Claim:
1. A fuel cell system including a fuel cell module and a control device; the fuel cell module comprising: a fuel cell stack formed by stacking a plurality of fuel cells for generating electricity by electrochemical reactions of a fuel gas and an oxygen-containing gas; a partial oxidation reformer for reforming a mixed gas of a raw fuel chiefly containing hydrocarbon and an oxygen-containing gas; a steam reformer for reforming a mixed gas of the raw fuel and water vapor; an evaporator for evaporating water and supplying the water vapor to the steam reformer; an exhaust gas combustor for combusting the fuel gas and the oxygen-containing gas discharged from the fuel cell stack to produce a combustion gas; a heat exchanger for raising a temperature of the oxygen-containing gas by heat exchange with the combustion gas and supplying the oxygen containing gas to the fuel cell stack, wherein the exhaust gas combustor is provided integrally in the heat exchanger, the control device comprising: a temperature detector unit comprising a steam reformer temperature sensor for detecting a temperature of the steam reformer and an evaporator temperature sensor for detecting a temperature of the evaporator; a carbon amount determination unit for determining an amount of carbon in the fuel gas supplied to the fuel cell stack depending on a required output of the fuel cell stack; a central processing unit and a memory having a program stored thereon, the program when executed by the central processing unit causing the control device to operate as: a carbon amount determination unit for determining an amount of carbon in the fuel gas supplied to the fuel cell stack depending on a required output of the fuel cell stack; an S/C determination unit for determining a range of steam/carbon ratio based on the temperature of the steam reformer; a water supply amount determination unit for determining a range of the water supply amount to the evaporator based on the amount of carbon and the steam/carbon ratio; an evaporator operating state determination unit for determining whether or not the temperature of the evaporator is a temperature determined based on the range of the water supply amount to the evaporator; and a reformer control unit adapted to control at least one regulator valve to supply only the raw fuel to the partial oxidation reformer and the water vapor mixed with the raw fuel to the steam reformer when it is determined by the evaporator operating state determination unit that the temperature of the evaporator is equal to or more than the temperature determined based on the range of the water supply amount to the evaporator.