NOVELTY - The catalytic reactor (5) comprises a reaction vessel (15) containing an annular catalytic reactor tube (40) with an interior volume divided into several fluidly connected chambers. The chamber(s) contains a catalyst bed (45). The vessel contains a reactant stream inlet (90) for directing a reactant stream to the chamber(s) and a reactant stream outlet (95) for directing a reactant stream from the chamber(s).    USE - For fuel cell power generating system (claimed), such as electrochemical fuel cells.    ADVANTAGE - The reactor tube permits increased mass flow rate for greater efficiency and reduced cost processing of hydrocarbon fuel for electrochemical fuel cells and other industrial applications. The reaction vessel provides homogeneous and faster reforming reaction and increases the amount of thermal energy transferred to the reactor tube per unit length. The septa reduces variation in thermal expansion and contraction of the reactor tube, and hence decreases catalyst crush. The septa improves integration of the overall reactor structure, and facilitates heat conduction through the catalyst beds.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for;    (1) A fuel cell power generating system comprises a catalytic reactor and a fuel cell stack. The catalytic reaction contains a reaction chamber (I) and a reaction chamber (II). The reaction chamber (I) comprises a catalyst bed for converting a reactant stream to a reformate stream (I) containing hydrogen. The reaction chamber (II) receives and converts the reformate stream (I) to a reformate stream (II) containing hydrogen. The fuel cell stack comprises at least one fuel cell fluidly connected to the catalytic reactor, such that the reformate stream (II) is directed to at least one fuel cell; and    (2) A fuel processing method, which involves supplying a reactant stream to the catalytic reactor and operating the system to obtain a reformate stream (II) containing hydrogen.    DESCRIPTION OF DRAWING(S) - The figure shows a vertical cross-sectional view of a catalytic reactor containing an annular cylindrical reactor tube comprising two reaction chambers.    Catalytic reactor (5)    Burner (10)    Reaction vessel (15)    Gas sleeves (25)    Inner wall (30)    Outer wall (35)    Annular catalytic reactor tube (40)    Catalyst bed (45)    Reactant stream inlet (90)    Reactant stream outlet (95)