Fuel cell power generation system

A fuel cell power generation system comprising:

• an oxide-ion-conducting first fuel cell that performs reformation of a fuel containing hydrocarbon and power generation;
• a proton-conducting second fuel cell, coupled to the first fuel cell via an air pipe, that performs power generation by being supplied with hydrogen from the first fuel cell;
• a fuel supply device that supplies the fuel;
• a combustor that combusts a fuel gas with air, the fuel gas and the air being emitted from the second fuel cell;
• a first heat exchanger that performs heat exchange between a fuel supplied to the first fuel cell and a fuel emitted from the first fuel cell;
• a second heat exchanger that performs heat exchange between a fuel heated at the first heat exchanger and gas emitted from the combustor;
• a third heat exchanger that performs heat exchange between a fuel gas emitted from the first fuel cell and a fuel gas supplied to the second fuel cell;
• a CO/CO2 converter that converts carbon monoxide emitted from the first fuel cell, to carbon dioxide;
• and
• a water recovery mechanism that recovers condensed water condensed by being cooled by the second heat exchanger and the third heat exchanger after being emitted from the first fuel cell,
• wherein a fuel utilization rate of the second fuel cell is higher than a fuel utilization rate of the first fuel cell,
• wherein the first fuel cell is operated in a first temperature area, and the second fuel cell is operated in a second temperature area in which a temperature is lower than that in the first temperature area, and
• wherein the second fuel cell is connected downstream of the first fuel cell such that hydrogen emitted from the first fuel cell is fuel to the second fuel cell and air emitted from the first fuel cell is supplied to the second fuel cell via the air pipe.