Patent ID: 7968243

Claim:
A method of operating a solid oxide fuel cell in which a gaseous supply stream comprising a reactive fuel species is delivered to an anode where the reactive fuel species are consumed in an electrochemical reaction to produce an anode exhaust stream which is depleted in reactive fuel species, and an oxidant supply stream is delivered to a cathode where reactive oxidant species are consumed in an electrochemical reaction to produce a cathode exhaust stream having an oxidant quality, which method comprises: predetermining the relationship between a concentration of reactive fuel species in the anode exhaust stream and a maximum current that can be drawn from the fuel cell without redox damage of the anode; assessing the concentration of reactive fuel species in the anode exhaust stream by measurement of the oxygen partial pressure of the anode exhaust stream; and adjusting the way in which the fuel cell is operated in order to optimize efficiency without oxidation damage of the anode based on the predetermined relationship between the concentration of reactive fuel species in the anode exhaust stream and the maximum current and the assessed concentration of reactive fuel species in the anode exhaust stream.