TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Component: The catalyst unit and the purifier are mounted in coaxial relation where the purifier is operable to receive and remove hydrogen from the reformed gases produced in the catalyst bed.The catalyst unit is cylindrical with an open inner annular space.The purifier comprises a separate cylindrical unit. It is resident within the annular space of the catalyst unit.The reformer includes a guard wall interposed between the catalyst bed and the purifier to prevent engagement of the catalyst with the purifier. The guard wall is constructed with passages facilitating movement of hydrogen through the purifier.The catalyst unit includes an outer wall of a high heat conducting material; fins secured to the outer wall and extending outwardly of the outer wall, where heating fluid passes over the catalyst unit and engages the fins and the outer wall for heating the catalyst bed; and a length defined by a linear axis. The fins project radially from the outer walls to establish a controlled flow of the flue gas (79) over the catalyst unit.The purifier has a length corresponding to the length of the catalyst unit. It is mounted on the linear axis.The reformer may comprise a linear metallic pressure vessel (19) having the catalyst bed disposed along the linear axis within the pressure vessel for producing hydrogen. The vessel is constructed and arranged with a feedstock inlet for introducing pressured fuel to be reformed to the catalyst bed and a reformed gas outlet.A hydrogen selective membrane is positioned downstream of the catalyst bed and operable to receive reformed gas and separate the reformed gas into hydrogen and raffinate.A heating unit is located upstream of the vessel. It directly discharges a heated fluid stream through the catalyst bed laterally to the linear axis of the catalyst bed.The heated fluid stream has a length corresponding to the length of the catalyst bed.The vessel is a cylinder that also contains the membrane.The catalyst bed surrounds the membrane in coaxial relationship within the vessel.The heating unit comprises a catalytic burner (75), and a passing and generating mechanism for passing a mixture of raffinate and air through the burner and generating the heated fluid stream for heating the vessel.The reformer further includes a header unit releasably secured to the other end of the vessel in a sealed fashion, where the feedstock inlet, the reformed gas outlet and the purified hydrogen all pass through the header unit; a raffinate pressure control for depressurizing the raffinate; a dispersing member located downstream of the depressurized raffinate for dispersing the depressurized raffinate in air; a feeding mechanism for feeding the raffinate/air mixture to the catalytic burner to supply the heated fluid stream; and a ceramic member having the membrane secured to its outer surface.The membrane is a metal member plated on the ceramic member.The guard wall is secured to the header unit and forms an inner annular wall for the catalyst bed.An end wall is connected to one end of the vessel.The feedstock inlet extends through the end wall into the catalyst bed to discharge the feedstock into the catalyst bed.A hydrogen recovery line extends through the end wall connected to the membrane to recover purified hydrogen.The reformed gas outlet extends through the end wall at a location spaced from the feedstock inlet.A hydrogen exit line communicates with the membrane. The feedstock inlet is coupled in counterflow fashion to the hydrogen exit line and/or the reformed gas outlet to preheat the feedstock. It includes a conduit arranged in a serpentine path located in the path of the heated fluid stream downstream of the vessel.The membrane is secured to a porous core.The catalytic burner is formed as a coating on the surface of the fins.A methanation catalyst is located on one side of the purifier membrane.The dispersing member comprises one or more porous members arranged such that the distributed raffinate/air mixture is richer at the feedstock inlet, and the raffinate/air mixture is leaner at the reformed gas outlet resulting in a higher heat flux per unit area in the catalyst bed, near the feedstock inlet than compared to in the catalyst bed near the reformed gas outlet.The header unit includes a mounting flange secured to the vessel and an end wall releasably secured to the flange.The flange is interconnected in fixed relation to the vessel with a seal located between opposed surface of the flange and the end wall to provide a high-pressure seal about the open end of the vessel.The vessel is mounted within a housing (36) including a vertical wall dividing the housing into an air inlet passageway.The passageway includes an air inlet chamber (90) on one side of the vertical wall to supply air to the heating unit located upstream of the vessel.The heating defines an exhaust passageway including an exhaust chamber (91) on the opposite side of the wall to discharge exhaust gas from the heating unit.The inlet and exhaust passageways are constructed and scaled to establish a low-pressure flow path of less than 1 psi through the air inlet passageway and the exhaust passageway.A counterflow exhaust heat recuperating system is provided for heating the inlet air supply. It comprises heat-transmitting plates (96) formed of thermally conductive material.Each plate is transversely mounted on the vertical wall and extends across the inlet and exhaust passageways. It includes distributed openings to permit free airflow and exhaust gas flow through the plates.Seals are provided between the plates and the vertical wall to prevent mixing exhaust and inlet gas streams, where the plates facilitate the flow of heat from the exhaust flue gas stream to the inlet air supply. They comprise a thermally insulating seals placed between each plate.The insulating seal is of adequate width to prevent mixing of the inlet air and exhaust flue gas. It is a ductile metal-member.Preferred Property: The membrane secured to the core has a thickness of 0.1-100 microns.    TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Method: The method further comprises feeding air to the burner; and pre-heating the air by transferring heat from the hot gas at a location downstream from the catalyst bed.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Material: The membrane is formed of a material from an inorganic molecular sieve, a pure metal, an alloyed metal, or an inorganic molecular sieved in combination with a pure or alloyed metal.The porous core is formed of a material from a porous metallic material, a porous ceramic material, a porous carbon-containing material, or a laminate of the materials.