NOVELTY - A fuel processor includes: (i) housing comprising a reformable fuel inlet, product gas outlet, combustible fuel inlet, or flue gas outlet; (ii) shift/methanator reactor vessel within the housing; (iii) combustion chamber comprising wall(s) forming inner annular space between the chamber wall(s) and the reactor vessel wall; and (iv) reformer reactor vessel comprising wall(s) forming an inner annular space between the reformer vessel wall and the combustion chamber wall.    USE - The fuel processor for reforming natural gas and other hydrocarbon fuels to produce a reformed fuel used in electrochemical fuel cell.    ADVANTAGE - The fuel processor is inexpensive and reduces the quantity of carbon monoxide in a mixture of hydrogen, carbon dioxide and carbon monoxide resulting from the reforming of hydrocarbon fuels. It renders the fuels usable in fuel cell applications without additional processing subsequent to reforming. The processor may utilize counter-current gas flow patterns for the reformer process gas stream and combustion flue gas stream to maximize fuel conversion, thus increasing efficiency. The reformer/combustion/shift/methanation coils work together balancing heat flow by gas flows and catalysts temperature requirements to function optimally. The insulation provides structural integrity to the fuel processor. It binds the fuel processing vessel components and tubing into a single integrated compact structure.    DETAILED DESCRIPTION - A fuel processor (10) includes:    (i) housing wall(s) one of which forming a reformable fuel inlet (40), product gas outlet (41), combustible fuel inlet (42), or flue gas outlet (43);    (ii) shift/methanator reactor vessel (14) comprising reactor vessel wall(s) disposed within the housing (11) and forming an outer annular space between the vessel wall(s) and the housing wall(s);    (iii) combustion chamber (39) comprising combustion chamber wall(s) and forming first inner annular space between the chamber wall(s) and the reactor vessel wall; and    (iv) reformer reactor vessel (28) comprising reformer vessel wall(s) and forming a second inner annular space between the reformer vessel wall and the combustion chamber wall.    The combustion chamber has a combustion products outlet in fluid communication with the flue gas outlet.    An INDEPENDENT CLAIM is also included for:    (a) reforming a hydrocarbon fuel by mixing the hydrocarbon fuel with water to form a fuel/water mixture;    (b) introducing the fuel/water mixture into a heat exchange zone of a fuel processor to form a preheated mixture comprising steam;    (c) introducing the preheated mixture into an input end of a reformer section disposed within the fuel processor to form a reformer section effluent comprising hydrogen, carbon monoxide, carbon dioxide and steam; and    (d) passing the reformer section effluent into a shift/methanator reactor vessel to form a hydrogen-rich product gas.    DESCRIPTION OF DRAWING(S) - The figure is a cross-sectional view of the fuel processor.    Fuel processor (10)    Housing (11)    Insulating foam (12)    Shift/methanator reaction vessel (14)    Shift catalyst (17)    Methanation catalyst (18)    Reformer reactor vessel (28)    Combustion chamber (39)    Fuel inlet (40)    Gas outlet (41)    Combustible fuel inlet (42)    Flue gas outlet (43)