Steam-reforming catalytic structure and pure hydrogen generator comprising the same and method of operation of same

A reactor/purifier for generating pure hydrogen, having in combination, a gas-porous screen structure washcoated with a steam-reforming catalyst;

• a stack of pairs of alternately connected relatively high and low pressure reactor chambers;
• said structure being sandwiched between a planar hydrogen-selective palladium alloy membrane and a planar gas-impermeable heat-conducting metal plate within the high pressure reactor chamber of each pair of alternating connected low and high pressure reactor chambers;
• means for reacting the catalyst-coated structure in each high pressure reactor chamber with steam and fuel and/or carbon monoxide at an appropriately controlled temperature between about 200° C. and 650° C. to produce hydrogen and carbon oxides within an isothermal temperature range in each high pressure reactor chamber while simultaneously permeating pure hydrogen therefrom through the membrane into the corresponding low pressure reactor chamber;
• and with the required heat transfer to and from said catalyst being provided in situ predominately by conduction through the corresponding metal plate.