Fuel cell power generating device

Abstract

A condenser condenses an unused exhaust gas exhausted from a fuel cell and recovers water, condensation-capacity detection means always monitors the condensation capacity of the condenser, control means controls an output of heat-transport-medium circulation means, stores the exhaust heat of the fuel cell in heat-using means when a sufficient condensation capacity is left, and stops the heat-transport-medium circulation means to complete exhaust-heat recovery when the condensation capacity lowers. Moreover, a fuel cell, a cooling pipe through which a first heating medium of carrying the heat of the fuel cell circulates, a cooling-water pump of circulating the first heating medium, and a fuel-cell-temperature detector of detecting the temperature of the fuel cell are used to operate a cooling-water pump until the temperature detected by the fuel-cell-temperature detector becomes a predetermine threshold value or less even after supply of a fuel and an oxidant to the fuel cell is stopped.

1 . A fuel-cell power-generation system comprising: 
 a fuel cell of generating power by using a fuel gas and an oxidant gas;    a condenser of condensing at least some of the unused exhaust gas exhausted from said fuel cell; and    water-using means of using the condensed water exhausted from said condenser for humidification of at least either of said fuel gas and said oxidant gas.    
     
     
         2 . The fuel-cell power-generation system according to  claim 1 , comprising: 
 heat exchange means of recovering exhaust heat due to the power generation of said fuel cell by means of heat exchange;    heat-using means of storing a heat transport medium recovering exhaust heat in said heat exchange means; and    circulation means of circulating said heat transport medium between said heat exchange means and said heat-using means.    
     
     
         3 . The fuel-cell power-generation system according to  claim 2 , wherein 
 said heat transport medium is constituted so as to pass through said condenser and contribute to condensation of the said unused exhaust gas in said condenser, and condensation-capacity detection means of detecting the condensation capacity of said condenser and control means of controlling the output of said circulation means in accordance with a detection signal of said condensation-capacity detection means are comprised.    
     
     
         4 . The fuel-cell power-generation system according to  claim 3 , wherein 
 said condensation-capacity detection means is condensed-water-temperature detection means of detecting the temperature of condensed water supplied from said condenser.    
     
     
         5 . The fuel-cell power-generation system according to  claim 4 , further comprising: 
 medium-temperature detection means of detecting a temperature of said heat transport medium recovering exhaust heat in said heat exchange means, and wherein said control means controls the output of said circulation means by also using the temperature of said heat transport medium detected by said medium-temperature detection means.    
     
     
         6 . The fuel-cell power-generation system according to  claim 3 , wherein 
 said condensation-capacity detection means is medium-temperature detection means of detecting the temperature of said heat transport medium coming into said condenser or medium-temperature detection means of detecting the temperature of said heat transport medium going out of said condenser.    
     
     
         7 . The fuel-cell power-generation system according to  claim 3 , wherein 
 said condensation-capacity detection means is heat-using-temperature detection means of detecting the temperature of said heat-using means.    
     
     
         8 . The fuel-cell power-generation system according to  claim 3 , wherein 
 said condensation-capacity detection means is medium-temperature detection means of detecting the temperature of said heat transport medium recovering exhaust heat in said heat exchange means.    
     
     
         9 . The fuel-cell power-generation system according to  claim 1 , wherein 
 the unused exhaust gas to be condensed by said condenser is at least either of an oxidant gas and a fuel gas.    
     
     
         10 . The fuel-cell power-generation system according to  claim 1 , wherein cooling is continued until the temperature of said fuel cell becomes a predetermined threshold value or less even after supply of said fuel and said oxidant to said fuel cell is stopped.  
     
     
         11 . The fuel-cell power-generation system according to  claim 1 , further comprising: 
 a cooling-circulation system through which a first heating medium set, so as to pass through said fuel cell and to carry the heat of said fuel cell, circulates;    heating-medium circulation means of circulating said first heating medium through said cooling-circulation system;    heat release means of releasing the heat of said first heating medium; and    temperature detection means of directly or indirectly detecting the temperature of said fuel cell, and    said heat-medium circulation means operates at least until the temperature detected by said temperature detection means becomes a predetermined threshold value or less after supply of said fuel and said oxidant to said fuel cell is stopped.    
     
     
         12 . The fuel-cell power-generation system according to  claim 11 , wherein 
 said heat release means has a heat exchanger of performing heat exchange between said first heating medium and a second heating medium, and    said heat exchanger performs said heat exchange until the temperature detected by said temperature detection means becomes a predetermined threshold value or less after supply of said fuel and said oxidant to said fuel cell is stopped.    
     
     
         13 . The fuel-cell power-generation system according to  claim 11  or  12 , wherein 
 the temperature detected by said temperature detection means is the temperature of said first heating medium or said cooling-circulation system.  
 
     
     
         14 . The fuel-cell power-generation system according to  claim 12 , wherein 
 the temperature detected by said temperature detection means is the temperature of said second heating medium.    
     
     
         15 . A fuel-cell power-generation system, comprising: 
 a fuel cell of generating power by receiving supply of a fuel and an oxidant;    a cooling-circulation system through which a first heating medium set, so as to pass through said fuel cell and to carry the heat of said fuel cell, circulates;    heating-medium circulation means of circulating said first heating medium in said cooling-circulation system;    heat release means of heat-exchanging the heat of said first heating medium with a second heating medium; and    heat detection means of detecting the temperature of said second heating medium, and    at least either of said heating-medium circulation means and said heat release means continuously operates until the temperature detected by said temperature detection means becomes a predetermined threshold value or less even after supply of said fuel and said oxidant to said fuel cell is stopped.