NOVELTY - A steam reformer with an internal hydrogen purification system has a concentric cylindrical architecture with the outermost shell nesting an annular combustion region, annular reforming region, an annular hydrogen transport region comprising a hydrogen-permeable membrane and an innermost polishing region for the product.    USE - In producing hydrogen of sufficient purity for use in a fuel cell.    ADVANTAGE - The apparatus combines steam reforming and purification of the hydrogen product in a practical way. The by-product gases, plus an amount of the hydrogen produced, provide the heat needed to drive the process and an additional fuel source is not required. Applying a second, polishing process to the hydrogen product to convert impurities into compounds which do not affect the operation of a fuel cell allows a cheaper, thin palladium alloy membrane to be used in the steam reforming process. A non-flammable fuel feedstock may be used. Using a concentric architecture with an outermost annular combustion chamber allows efficient integration of heat transfer and a compact design.    DETAILED DESCRIPTION - A steam reformer comprises:    (a) a reformation chamber which receives a reformation feedstock and contains a reformation catalyst, and which produces a reformation product flow including hydrogen;    (b) a hydrogen purification module, which receives the reformation flow and divides it into a by-product flow and a hydrogen product flow and which includes multiple stacked planar elements, at least one of which carries a hydrogen-permeable membrane. The elements includes:    (1) apertures, which are aligned in the stack and define multiple manifolds carrying the reformation product flow to a first side of the membrane,    (2) the by-product flow from the first side of the membrane to the module's by-product outlet,    (3) and the hydrogen product flow from the second side of the membrane to the module's hydrogen product outlet.    INDEPENDENT CLAIMS are also included for:    (a) a method of manufacturing a hydrogen-permeable structure comprising:    (1) coupling a hydrogen-permeable foil to a fame by ultrasonic welding to establish a first gas-tight seal,    (2) coupling a structural member to the frame to establish a second gas-tight seal,    (3) the foil, the frame and the structural member are coupled via the first and second gas-tight seals to form a first chamber on one side of the foil and a second chamber on the other side of the foil, such that hydrogen gas introduced into the first chamber passes through the hydrogen-permeable foil;    (b) a hydrogen-forming feedstock comprising:    (i) a water-miscible organic compound containing hydroxyl, aldehyde, ether, ketone or carboxylic acid groups, or a mixture, and having a vapor pressure of less than 100 Torr at 100degreesC,    (ii) at least one molar equivalent of water, such that the mixture is a homogeneous liquid at 20degreesC.    DESCRIPTION OF DRAWING(S) - The figure shows a cross-section of a steam reformer.    Outermost metal tube (50)    Air supply inlet (34)    Combustion by-product ports (38)    Combustion region (6)    Combustion catalyst (100)    Feedstock inlet (30)    Innermost metal tube (56)    Reforming region (62)    Catalyst (102)    Membrane tube (54)    Supporting tension spring (104) End caps (101)    Metal gauze (110) Polishing catalyst (106)    Purified hydrogen outlet (56b)