Patent ID: 6872481

Claim:
A method of operating a fuel cell system to satisfy transient loads wherein said system comprises a reformer producing a hydrogen-containing reformate stream which is consumed in a fuel cell stack to satisfy the transient load, said method comprising the steps of: providing a cold-flame vaporizer; supplying to said cold-flame vaporizer a hydrocarbon liquid inlet stream at a first mass flow rate and an oxidant inlet stream at a second flow mass rate, said oxidant comprising oxygen; at least partially oxidizing a portion of the hydrocarbon liquid within the cold-flame vaporizer to transfer heat to a remaining portion of the hydrocarbon liquid causing vaporization thereof, thereby producing an outlet stream comprising vaporized fuel; varying said first and second flow rates while controlling an oxygen to carbon molar ratio within said cold-flame vaporizer within a range sufficient to cause said vaporization of said remaining portion of hydrocarbon liquid without causing auto-ignition thereof, and to maintain said outlet stream within a first temperature range; and reforming said outlet stream in a reformer to produce the reformate steam for consumption in said stack to satisfy the transient load.