Fuel cell system and method for operating the fuel cell system

Abstract

A fuel cell system and method of operation in which the fuel cell system has a fuel cell unit with anode and cathode, a media flow path for supplying substantially pure hydrogen to the anode, a media flow path for the cathode, an anode exhaust-gas flow path and a cathode exhaust-gas flow path. A fan for supplying air to the cathode is provided in the flow path of the cathode, and a catalytic burner is arranged in the cathode exhaust-gas flow path. The anode exhaust-gas flow path opens into the catalytic burner and/or into the cathode exhaust-gas flow path upstream of the catalytic burner. The combined, catalytically converted fuel cell exhaust-gas flow is passed into an expansion machine.

1 . A fuel cell system comprising: 
 a fuel cell unit having an anode and a cathode;    a media flow path leading to the anode;    a media flow path leading to the cathode;    an anode exhaust-gas flow path;    a cathode exhaust-gas flow path;    a fan provided in the flow path of the cathode, for supplying air to the cathode; and    a catalytic burner arranged in the cathode exhaust-gas flow path, and the anode exhaust-gas flow path opening into at least one of the catalytic burner and the cathode exhaust-gas flow path upstream of the catalytic burner;    wherein the catalytically converted fuel cell exhaust-gas flow is combined and passed into an expansion machine.    
     
     
         2 . The fuel cell system according to  claim 1 , wherein: 
 the fuel cell unit comprises a plurality of fuel cell stacks;    at least two fuel cell stacks are connected in parallel in terms of media flow; and    at least one fuel cell stack is arranged in series, in terms of media flow, with the parallel-connected fuel cell stacks.    
     
     
         3 . The fuel cell system according to  claim 1 , wherein the expansion machine comprises one of an exhaust-gas turbocharger or a turbogenerator.  
     
     
         4 . The fuel cell system according to  claim 1 , wherein the fan is coupled to the expansion machine via a common shaft.  
     
     
         5 . The fuel cell system according to  claim 1 , wherein the catalytic burner has a metering device for fuel.  
     
     
         6 . The fuel cell system according to  claim 1 , further comprising a gas generation system having a unit for generating a hydrogen-rich product gas and a cleaning unit for selectively separating hydrogen out of the product gas, upstream of the fuel cell unit; 
 wherein separated hydrogen is fed to the fuel cell unit and residual gas is fed to the catalytic burner.    
     
     
         7 - 13 . (canceled)