Hydrogen passivation shut down system for a fuel cell power plant

Abstract

The invention is a hydrogen passivation shut down system for a fuel cell power plant ( 10 ). An anode flow path ( 24 ) is in fluid communication with an anode catalyst ( 14 ) for directing hydrogen fuel to flow adjacent to the anode catalyst ( 14 ), and a cathode flow path ( 38 ) is in fluid communication with a cathode catalyst ( 16 ) for directing an oxidant to flow adjacent to the cathode catalyst ( 16 ) of a fuel cell ( 12 ). Hydrogen fuel is permitted to transfer between the anode flow path ( 24 ) and the cathode flow path ( 38 ). A hydrogen reservoir ( 66 ) is secured in fluid communication with the anode flow path ( 24 ) for receiving and storing hydrogen during fuel cell ( 12 ) operation, and for releasing the hydrogen into fuel cell ( 12 ) whenever the fuel cell ( 12 ) is shut down.

1 . A hydrogen passivation shut down system for a fuel cell power plant ( 10 ), the system comprising: 
 a. at least one fuel cell ( 12 ) for generating electrical current from hydrogen containing reducing fluid fuel and oxygen containing oxidant reactant streams, the fuel cell ( 12 ) including an anode catalyst ( 14 ) and a cathode catalyst ( 16 ) on opposed sides of an electrolyte ( 18 ), an anode flow path ( 24 ) in fluid communication with the anode catalyst ( 14 ) for directing the hydrogen fuel to flow through the fuel cell ( 12 ) and adjacent the anode catalyst ( 14 ), and a cathode flow path ( 38 ) in fluid communication with the cathode catalyst ( 16 ) for directing the oxidant stream to flow through the fuel cell ( 12 ) and adjacent the cathode catalyst ( 14 );    b. a hydrogen inlet valve ( 52 ) secured between a hydrogen containing reducing fluid fuel source ( 54 ) and the anode flow path ( 24 ) for selectively permitting the hydrogen fuel to flow into the anode flow path ( 24 );    c. an oxidant inlet valve ( 56 ) secured between an oxygen containing oxidant source ( 58 ) and the cathode flow path ( 38 ) for selectively permitting the oxidant to flow into the cathode flow path ( 38 );    d. hydrogen transfer means secured in communication between the anode flow path ( 24 ) and the oxidant flow path ( 38 ) for selectively permitting flow of the hydrogen fuel between the anode flow path ( 24 ) and the cathode flow path ( 38 ); and,    e. hydrogen reservoir means secured in fluid communication with the anode flow path ( 24 ) for storing the hydrogen fuel whenever the hydrogen inlet valve ( 52 ) is open to permit flow of the hydrogen fuel through the anode flow path ( 24 ), and for releasing hydrogen fuel into the anode flow path ( 24 ) whenever the hydrogen inlet valve ( 52 ) is closed.    
     
     
         2 . The system of  claim 1 , wherein the hydrogen reservoir means comprises a hydrogen vessel ( 66 ) secured outside the fuel cell ( 12 ) in fluid communication with the anode flow path ( 24 ), the hydrogen vessel including a hydrogen storage media stored within the vessel ( 66 ).  
     
     
         3 . The system of  claim 1 , wherein the hydrogen reservoir means comprises a hydrogen storage media secured in fluid communication with the anode flow path ( 24 ).  
     
     
         4 . The system of  claim 1 , wherein the hydrogen reservoir means comprises a hydrogen storage media secured within the anode flow path ( 24 ).  
     
     
         5 . The system of  claim 1 , further comprising a hydrogen sensor means secured in communication with the fuel cell ( 12 ) for detecting a concentration of hydrogen within the anode flow path ( 24 ) and the cathode flow path ( 38 ).