Patent ID: 7323262

Claim:
A fuel cell system, comprising: (a) a fuel cell having a cathode, a first reactant inlet and a first reactant outlet both connected to the cathode, and an anode, a second reactant inlet and a second reactant outlet both connected to the anode; (b) a first reactant supply subsystem including a first reactant supply means for supplying a first reactant incoming stream to the first reactant inlet of the fuel cell; (c) a second reactant supply subsystem for supplying a second reactant incoming stream to the second reactant inlet of the fuel cell; (d) a monitoring device for monitoring a fuel cell state variable indicative of flooding of the fuel cell; (e) a controller for controlling the first reactant supply means to provide an additional amount of the first reactant to the fuel cell cathode based on the fuel cell state variable, and for controlling the second reactant supply means to provide an additional amount of the second reactant to the fuel cell anode based on the fuel cell state variable, whereby flooding occurring in either one of the anode and cathode is displaced by the additional amounts of the first and second reactants; and (f) a second reactant recirculation line connected between the second reactant outlet and the second reactant inlet, and a second reactant purge means connected to the second reactant outlet, wherein the controller is operable to control the second reactant purge means to purge at least a portion of the second reactant exhaust stream from the second reactant outlet when the fuel cell state variable indicates the fuel cell is flooded.