NOVELTY - A fuel processor includes a hydrocarbon conversion zone for converting the hydrocarbonaceous fuel into a product gas, a steam generator, a water-gas shift reaction zone containing a catalyst for water-gas shift conversion reaction, and a carbon monoxide removal zone having a catalyst for oxidizing carbon monoxide or for methanation of carbon monoxide.    USE - For converting hydrocarbonaceous fuel into hydrogen and carbon dioxide.    ADVANTAGE - The processor is safe fuel processor in which damage from accidental ignition can be easily contained. It minimizes the number of sealings to minimize leakage of gas to the surroundings. It is manufactured at low costs and from mass-produced parts.    DETAILED DESCRIPTION - A fuel processor comprises a vessel having side wall and outlet, a first fluid flow path (4) located in or at the outside of the side wall, a hydrocarbon conversion zone (5) for converting the hydrocarbonaceous fuel into a product gas, a steam generator, a water-gas shift reaction zone (6) having an inlet and outlet and contains a catalyst for water-gas shift conversion reaction, a second fluid flow path (14) extending from the outlet of the conversion zone to the inlet of the water-gas shift reaction zone, a carbon monoxide removal zone (8) having catalyst for oxidizing carbon monoxide or for methanation of carbon monoxide, and third fluid flow path (17) extending from the outlet of the water-gas shift reaction zone to the inlet of the carbon monoxide removal zone. The first fluid flow path, the hydrocarbon conversion zone, and the carbon monoxide removal zone have inlets and outlets. The steam generator and the water-gas shift reaction zone are contained in the vessel.    An INDEPENDENT CLAIM is also included for a fuel cell system comprising a fuel processor and proton exchange membrane fuel cell.    DESCRIPTION OF DRAWING(S) - The figure shows a longitudinal section of the fuel processor.    Inner shell (2)    Outer shell (3)    First fluid flow path (4)    Hydrocarbon conversion zone (5)    Water-gas shift reaction zone (6)    Auxiliary water-gas shift reaction zone (7)    Carbon monoxide removal zone (8)    Evaporator (11)    Second fluid flow path (14)    Third fluid flow path (17)    Fourth fluid flow path (24)    Water reservoir (29)