Patent ID: 7250229

Claim:
A procedure for starting-up a fuel cell system that is shut down, the shut down system comprising a source of hydrogen containing fuel, a fuel cell including a cathode flow field adjacent the cathode of the cell on one side of the cell electrolyte and an anode flow field adjacent the anode of the cell on the other side of the cell electrolyte, an anode recycle loop for recirculating at least a portion of the anode flow field exhaust through the anode flow field, wherein both the anode flow field and cathode flow field are filled with air, and the primary electricity using device is disconnected from the fuel cell external circuit, the start-up procedure comprising the steps of: (A) initiating a recirculation, through the recycle loop, of the anode flow field exhaust, which is initially 100% air, and then providing a flow of hydrogen containing fuel into the recirculating anode exhaust to create a mixture of hydrogen and air within the recycle loop, wherein the recycle loop includes a plurality of burners disposed in series, and providing a separate flow of fuel to each burner, wherein hydrogen and oxygen are catalytically consumed within each of the burners; (B) catalytically reacting hydrogen and oxygen within the mixture on a catalyst within the recycle loop as the hydrogen and oxygen circulates through the recycle loop in contact with a catalyst to form water, and continuing to add hydrogen containing fuel to the recirculating mixture until substantially no oxygen remains in the recycle loop, including regulating the rate at which fuel is added such that the recirculating gases do not contain a flammable ratio of hydrogen and oxygen when they contact the catalyst or when they enter the anode flow field; and, (C) after substantially no oxygen remains in the recycle loop, (i) increasing the rate of fuel flow into the anode flow field to a normal operating flow rate, (ii) providing an oxidant into the cathode flow field at a normal operating flow rate, and, (iii) connecting the primary electricity using device to the external circuit.