TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Apparatus: The steam reformer may further comprise:(i) a combustion chamber receiving a combustion fuel and providing heat energy to the reformation process, such that the combustion chamber is within and thermally coupled to the reformation chamber, but there is no contact between its fluids and those of the reformation process,(ii) a tubular structure (preferably double-walled) defining a combustion region, which receives a combustion fuel and is then coupled to the steam reformation process by placing the structure (partially) within the reformation chamber;(iii) a vaporization chamber, which receives and vaporizes the feedstock for delivery to the reformation chamber, and which includes a conduit carrying the feedstock through the vaporization chamber.The stacked elements carrying a hydrogen-permeable membrane include a frame part which is coupled to the membrane by ultrasonic welding. At least 2 of the stacked elements carry a hydrogen-permeable membrane and the by-product flow is presented to them in a serial and/or parallel flow arrangement. Preferred Method: The second gas-tight seal is established by a welding process including a liquid phase.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The hydrogen-permeable membrane contains a hydrogen-permeable foil comprising palladium and/or a palladium alloy. Preferably the foil comprises copper (35-45 wt.%, preferably 39.5-40.5 wt.%), less than 200 ppm (preferably less than 100 ppm) each of carbon and oxygen and palladium (preferably the balance). The frame of the hydrogen-permeable structure is made of copper, nickel or their alloys.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Feedstock: The organic compound is:(i) a polyhydroxy alcohol or its oligomers, or polyether;(ii) (di)ethylene gylcol, (di)propylene glycol or glycerol. EXAMPLE - The figure shows a cross-section of a steam reformer (12) comprising an outermost metal tube (50) with an air supply inlet (34) and ports for combustion by-products (38). In the combustion region (60), there is a combustion catalyst (100) near the air inlet (34). An inlet (30) carrying a mixture of methanol and water under pressure passes through the end wall of the tube (50) and forms a coil (30a) wrapped about the innermost metal tube (56) and opening into the reforming region (62). The mixture is delivered as vapor after passing through the elevated temperatures of the combustion region (60). The reforming region (62) contains a catalyst (102) and hydrogen is produced in the vicinity of the membrane tube (54) of hydrogen-permeable palladium alloy, which contains a supporting tension spring (101). The ends of the membrane tube are sealed with metal caps (104) and the tube is surrounded by a metal gauze (106), which holds the catalyst (102) around the tube. Hydrogen migrates by pressure difference into a hydrogen transport region (64) and towards the open end (56a) of the tube (56), which contains a polishing catalyst (110) to remove impurities, e.g. carbon monoxide and carbon dioxide. Purified hydrogen exits at the opposite end of the tube (56b). A tubular structure (54) was formed by ultrasonically welding a Pd-40Cu foil of thickness 25 um over a central cut-out in a copper foil frame. The structure was wrapped around a stainless steel tension spring which had an outer diameter of 2.8 cm and the overlapping edges were ultrasonically welded to form a tubular shape. Copper end-caps were then brazing to the exposed ends parts of the frame to complete a gas-tight structure. The membrane was 15 cm long. A copper tube (56) of outside diameter 1.8 cm was sealed to one end cap (the left one). The other end of the tube terminated 0.3 cm from the other end cap and the tube was filled with greater than G1 greater than 80 (RTM: supported nickel composition methanation catalyst). The reforming region of the apparatus (62) was filled with K3-110 (RTM: Cu/Zn supported catalyst). The rest of the apparatus was constructed from stainless steel. The apparatus was electrically heated to 200-300degreesC, then the heater was turned off and a feedstock comprising methanol (405 ml) and deionized water (180 ml) was pumped in at 200 psig. Combustion of a hydrogen-depleted gas inside the apparatus maintained a temperature of 300-350degreesC and provided all of the heat required by the process. Product hydrogen at ambient pressure was obtained at 2 l/minute and contained less than 10 ppm each of CO and CO2. During a trial lasting 6 hours, the reformer was operated without an external source of heating.