TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Component: The intermediate layer of the gas separation module comprises at least two sub-layers of particles and binder metal. At least one distributed combustion chamber is in a heat transferring relationship with the catalyst bed. The gas separation module is a tube. The intermediate layer of the gas separation module comprises a gradient of particle size from a surface of the intermediate layer proximate to the porous substrate to a surface of the intermediate layer distal to the porous substrate. A metal hydride precursor is separated from the reaction chamber by the gas separation module. It is in gaseous fluid communication with the gas separation module, where the metal hydride precursor is located to react with hydrogen permeating the gas separation module to form a metal hydride. Additional particles are deposited over the particles and binder metal and additional binder metal is deposited onto the additional particles. The reactor is a steam reforming reactor and the catalyst bed is a steam reforming catalyst bed. It is a dehydrogenation reactor and the catalyst bed is a dehydrogenation catalyst bed.    TECHNOLOGY FOCUS - METALLURGY - Preferred Material: The hydrogen-selective membrane is formed of palladium or its alloy with at least one of the metals from copper, silver, gold, platinum, ruthenium, rhodium, yttrium, cerium, or indium. The porous substrate is a porous ceramic substrate or a porous metal substrate from stainless steel, an alloy comprising chromium and nickel, a nickel based alloy, and an alloy comprising chromium, nickel, or molybdenum. The binder metal is a hydrogen-selective hydrogen-permeable metal or its alloy. The particles of the intermediate layer are metal particles, metal oxide particles including aluminum oxide particles, ceramic particles, and/or zeolite particles. The particles of the intermediate layer are a preactivated powder. Preferred Property: The intermediate layer has an average thickness of 0.3-3 microns.