| 主权项 |
1. A fuel cell system comprising:
a fuel cell stack formed by stacking a plurality of fuel cells, said fuel cells each including an electrolyte electrode assembly and a separator stacked together, said electrolyte electrode assembly including an anode, a cathode, and an electrolyte interposed between said anode and said cathode; a heat exchanger for heating an oxygen-containing gas to be supplied to said fuel cell stack; a preliminary reformer for reforming a mixed fuel of a raw fuel chiefly containing hydrocarbon and water vapor by steam reforming to produce a fuel gas; a single exhaust gas passage in which all of an exhaust gas discharged from both the cathode and anode during power generation reactions is combined prior to all of the exhaust gas discharged from both the cathode and the anode during power generation reactions being allocated between—first and second heating mechanisms, the exhaust gas including an exhaust fuel gas discharged from the anode and an exhaust oxygen-containing gas discharged from the cathode; the first heating mechanism, the first heating mechanism directly supplying, without further processing, some of the exhaust gas from the single exhaust gas passage to said preliminary reformer as a heat source for directly heating said preliminary reformer; the second heating mechanism, the second heating mechanism supplying the remaining exhaust gas from the single exhaust gas passage to said heat exchanger as a heat source for heating the oxygen-containing gas, and supplying the heat generated in said heat exchanger to said preliminary reformer as a heat source for indirectly heating said preliminary reformer, all of the exhaust gas discharged from the anode and cathode being directed to the first and second heating mechanisms, wherein said preliminary reformer and said heat exchanger are provided near said fuel cell stack, and said heat exchanger is provided outside and physically separated from said preliminary reformer so as to form an indirect heating space of the second heating mechanism between the heat exchanger and the reformer, heat generated in the heat exchanger being conveyed by radiation or convection through the indirect heating space to the preliminary reformer; and a control mechanism for controlling said first and second heating mechanisms to maintain the state of said preliminary reformer to have a predetermined reforming condition value, the control mechanism controlling a control valve, the control valve operable to allocate an amount of the exhaust gas between the first and second heating mechanisms based on a temperature reading in the preliminary reformer, wherein the fuel gas produced by said preliminary reformer is supplied to said anode, and water produced in power generation reaction of said electrolyte electrode assembly is used for reforming the fuel gas by steam reforming at said anode. |
