TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: A part of the quantity of produced heat by combusting the solid pyrotechnic charge is utilized for heating the membrane, and is transferred to the membrane via a material, acting as a thermal bridge, preferably at high thermal conductivity. The method further comprises cooling at least one part of the produced hydrogenated gas, before its purification, and filtering at least one part of the produced hydrogenated gas to remove at least one part of solid combustion residues. A part of the quantity of the heat extracted during the cooling step is utilized for heating the membrane. The filtering step is carried out before the purifying step. The method comprises producing hydrogenated gas, filtering at least one part of hydrogenated gas to remove at least one part of the solid combustion residues, cooling the part of the filtered hydrogenated gas, and purifying the filtered and cooled hydrogenated gas. Preferred Components: The solid pyrotechnic charge is a pyrotechnic charge containing a pyrotechnic product containing 96 mass% of an inorganic oxidizing component and a hydrogenated reducing component consisting of inorganic hydrides, borazane and polyaminoboranes. The hydrogenated reducing component includes inorganic hydrides consisting of inorganic borohydrides, preferably alkali and alkaline earth metal borohydrides (comprising sodium borohydride, lithium borohydride and magnesium borohydride), and consists of borazane (preferred) and polyaminoboranes. The inorganic oxidizing component includes perchlorates, dinitro amides, nitrates and metal oxides, preferably ammonium perchlorate, ammonium dinitroamide, strontium nitrate and iron oxide. The pyrotechnic product contains: 40-80 mass%, preferably more than 70 mass% of hydrogenated reducing component and 20-60 mass%, preferably 25-45 mass% of inorganic oxidizing component.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The annular combustion chamber is arranged around the separation membrane. The insulated enclosure containing a material provides a thermal bridge between the combustion chamber and the membrane. The device further comprises a gas cooling unit arranged in a downstream of the combustion chamber and in an upstream of the membrane, and a gas filtering unit. A part of a tube is present in communication with the combustion chamber and the separation membrane. The separation membrane is a palladium or alloy containing palladium membrane.