Lamp Processing of the Surface of PdCu Membrane Foil: Hydrogen Permeability and Membrane Catalysis

We have studied the effect of surface lamp processing on the hydrogen permeability of membrane foil produced by rolling an ingot of a Pd–Cu solid solution. Such processing has been shown to remove sorption products from the membrane surface and to significantly improve the hydrogen permeability of the membranes at temperatures of up to 300°C. The use of a reactor with a cleaned PdCu membrane allows the hydrogen yield in the methanol steam reforming process in the presence of a Ni0.2Cu0.8/Ce0.3Zr0.7O2–δ catalyst to be raised relative to that in a conventional flow reactor owing to the displacement of thermodynamic equilibrium as a result of the removal of hydrogen from the reaction zone. The effect of membrane surface cleaning by lamp processing is most clearly demonstrated by examining the yield of high-purity hydrogen in the permeate zone. Whereas at 360°C the yield of high-purity hydrogen in a reactor containing a membrane with a cleaned surface increased by just 15%, membrane surface cleaning by lamp processing ensured a 15‑fold gain at 260°C. This is due to the considerable difference between the hydrogen permeabilities of the membranes at low temperatures and its gradual decrease at high temperatures.