NOVELTY - A fuel processor has a reformer converting a hydrogen-containing fuel to a hydrogen-containing reformate; a shift reactor to reduce carbon monoxide levels of the reformate; a preferential oxidation reactor to further reduce carbon monoxide levels of the reformate from the shift reactor; and a first combustion heater system coupled to the reformer, shift reactor or preferential oxidation reactor.    USE - For rapidly achieving operating temperature during startup.    ADVANTAGE - The system is capable of heating the fuel processor components quickly to achieve proper operating temperatures for startup. It maximizes this heat input into the fuel processor while minimizing the tendency to form carbon. It is capable of heating the fuel processor components while minimizing the use of electrical energy during startup and the reliance on catalytic reactions. It enables the potential usage of inexpensive copper-zinc (CuZn) catalyst only without the need for an additional coolant loop. The tight control of temperatures within the fuel processor enables the optimization of reactor size and catalyst usage resulting in reduced active metal costs. The system provides improved transient carbon monoxide concentration performance.    DETAILED DESCRIPTION - A fuel processor for rapidly achieving operating temperature, comprises a reformer converting a hydrogen-containing fuel to a hydrogen-containing reformate; a shift reactor in fluid communication with the reformer, and being operable to reduce carbon monoxide levels of the reformate; a preferential oxidation reactor in fluid communication with the shift reactor, and being operable to further reduce carbon monoxide levels of the reformate exiting the shift reactor; and a first combustion heater system (12) coupled to the reformer, shift reactor or preferential oxidation reactor. The first combustion heater system is operable in a lean state to produce thermal energy as a product of the combustion of air and fuel in the form of a first heated exhaust stream.    DESCRIPTION OF DRAWING(S) - The figure is a schematic view illustrating a fuel processor.    First combustion heater system (12)    Reformer (14)    Heat exchanger (16)    Fuel cell stack (22)    Second combustion heater system (24)    Catalyst combustor (26)    First heated exhaust stream (32)    Air control valve (64)    Cathode back pressure valve (66)    Second heated exhaust stream (70)