A method for improving the efficiency of a hydrocarbon catalytic reformer
and close-coupled fuel cell system by recycling a percentage of the anode
exhaust syngas directly into the reformer in a range between about 20%
and about 60%. Oxygen is supplied to the reformer at start-up. Under
equilibrium conditions, oxygen required for reforming of hydrocarbon fuel
is derived entirely from endothermic reforming of water and carbon
dioxide in the recycled syngas. Recycling of anode syngas into the
reformer increases fuel efficiency, adds excess water to the reformate to
increase protection against anode coking, and protects the fuel cell
stack against air- and water-borne contaminants. A method for producing
an excess amount of syngas for exporting for other purposes is also
provided.