TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The reforming catalyst comprises Group VIII transition metal(s) on a support, preferably nickel on alumina.The hydrogen-permeable selective membrane comprises Group VIII transition metal(s) or their alloys, preferably palladium (Pd), platinum (Pt) or Pd or Pt alloy. The membrane support provides an intermediate layer between the membrane and the catalyst.Preferred Property: The membrane has a thickness of 10 Angstrom - 150 mum, preferably 0.5-10 mum. It has a permeability of 8x10-4 - 80 standard m3/m2/sec/bar 0.5, preferably 8x10-3 to 70 standard m3/m2/sec/bar 0.5. The fuel gas is hydrogen.    TECHNOLOGY FOCUS - METALLURGY - Preferred Composition: The membrane comprises (wt.%) Pd alloy with copper (30-50), Pd alloy with silver (5-30), Pd alloy with yttrium (1-10), Pd alloy with holmium (1-10), Pd alloy with gold (10), Pd alloy with ruthenium (1-10), and Pd alloy with cerium (1-10). The steam reforming reactor is constructed of an alloy containing chromium (Cr) (15-20), and nickel (Ni) (5-15), more preferably stainless steel comprising Cr (18), Ni (8) and iron (balance).    TECHNOLOGY FOCUS - CERAMICS AND GLASS - Preferred Component: The hydrogen-permeable membrane is situated on a support, preferably a porous metal or ceramic support.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The inside section is packed with a methanation catalyst. The fuel cell is a high pressure fuel cell, preferably a high pressure molten carbonate fuel cell. The vaporizable hydrocarbon is natural gas, methane, methanol, ethane, ethanol, propane, butane, 1-4C light hydrocarbons or light petroleum fractions including naphtha, diesel, kerosene, jet fuel or vacuum gas oil, preferably natural gas, methane, methanol or naphtha. The vaporizable hydrocarbon and steam provide a minimum overall oxygen:carbon ratio of 2:1, preferably 2:1-3:1.    TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Process: The FDC used to drive the reaction comprises:(a) preheating either a fuel gas or oxidant or both to a temperature that exceeds the autoignition temperature of the fuel gas and oxidant when they are mixed; passing the fuel gas and oxidant into a heating zone which is in heat transferring contact along a portion of the reaction zone; and(b) mixing the fuel gas and oxidant in the heating zone in a manner that autoignition occurs, resulting in combustion without high temperature flames so providing uniform, controllable heat over a substantial portion of the heating zone which is in contact with the reaction zone.The fuel gas is passed through tubes in the heating zone. The oxidant is air, and the air and fuel gas used for FDC are heated to 1,000-2,300 degrees F. The fuel gas is mixed with oxidant in increments so that, upon autoignition, the temperature of the resulting combustion gas will rise not more than 20-200 degrees F. The oxidant, the hydrogen and air are combusted at a ratio of hydrogen to oxygen of 2:1, resulting in a flue gas stream that has a high concentration of nitrogen on a dry basis. A sweep gas is used to promote the diffusion of hydrogen through the membrane, preferably a sweep gas from steam, CO2, nitrogen and condensable hydrocarbons, more preferably steam. A vacuum is used to promote the diffusion of hydrogen through the membrane. The temperature in the reaction zone is 300-600, preferably 400-500 degrees C at 10-50 bar. EXAMPLE - A Pd-on tantalum membrane was encased in a half inch diameter stainless tube and the void space filled with bulk-metal nickel catalyst (20 g) having a nitrogen content of 45 wt.%. The unit was swept with nitrogen and the catalyst sample pretreated with hydrogen at 420 degrees C. With steam flowing through the unit under 80 psig back pressure, the temperature was raised to 500 degrees C and a full vacuum drawn on the permeate side of the membrane. A reactor was charged with nickel catalyst (56 g) and fed a mix of methane and steam. The unit operating pressure was 380 psig. At 500 degrees C, product effluent analysis showed that 92% methane conversion per pass, 99% hydrogen permeation of the membrane, and 94% CO2 concentration in the product effluent. Analysis of the permeate gas showed that hydrogen had 99 % purity.