NOVELTY - Pre-reformer for rapidly heating reactants for use in fuel reformer, comprises: (i) combustion section having a catalyst providing non diffused flow path through the combustion chamber for passage of combustion gases and heat; and (ii) heat recovery section in fluid communication with the combustion chamber, having heat exchanging element(S) with inlet for receiving reactants and outlet for directing heated reactants out of the heat recovery section.    USE - For rapidly heating of reactants for use in a fuel reformer of integrated fuel processing apparatus.    ADVANTAGE - Rapid start-up of the fuel processor is provided, and a more stable temperature profile is maintained during the operation of the reformer.    DETAILED DESCRIPTION - Pre-reformer (10) for rapidly heating of reactants for use in a fuel reformer, comprises:    (a) a combustion section having an outer wall (6) enclosing a combustion chamber (36) and a catalyst disposed within the combustion chamber, with the catalyst providing a non diffused flow path through the combustion chamber for the passage of combustion gases and heat;    (b) optionally, a mixer upstream of the combustion chamber for mixing at least combustion reactants;    (1c) optionally, heating unit upstream of the combustion chamber for preheating the combustion reactants before contacting the catalyst; and    (d) heat recovery section in fluid communication with the combustion chamber, having an outer wall (8) defining a heat recovery chamber (38), with heat exchanging element(S) (18a, 18b) being disposed within the heat recovery chamber, the heat exchanging element having an inlet (22, 24) for receiving reactants and an outlet (26, 28) for directing heated reactants out of the heat recovery section, where the combustion section is elevated relative to the heat recovery section.    INDEPENDENT CLAIMS are also included for:    (a) method for the rapid start-up of fuel processor, comprising, in a pre-reformer, combusting a fuel and an oxygen containing gas over a combustion catalyst to generate heated combustion gases within a combustion section, optionally, pre-heating the fuel and/or oxygen-containing gas prior to the combustion, optionally, mixing the fuel and/or oxygen-containing gas prior to the combustion; passing the heated combustion gases through the combustion catalyst and into a heat recovery section; exchanging heat between the heated combustion gases and a fuel reformer reactant in the heat recovery section to generate a heated reactant, where the combustion section is elevated relative to the heat recovery section; and directing the heated reactant to a bottom-fed fuel reformer; and    (b) an integrated fuel processing apparatus for rapid start-up comprising a pre-reformer configured to provide a heated fuel reforming reactant to a fuel reformer, and fuel reformer connected to outlet of heat exchanging element for receiving a heated reactant from the pre-reformer.    DESCRIPTION OF DRAWING(S) - The figure is a cross sectional view of a pre-reformer.    Outer walls (6, 8)    Pre-reformer (10)    Heat exchanging elements (18a, 18b)    Inlets (22, 24)    Outlets (26, 28)    Combustion chamber (36)    Heat recovery chamber (38)