Palladium membranes are attractive and important because of its complete hydrogen selectivity. However, palladium is expensive and limited in resources. In a series of our research, an amorphous Zr₃₆Ni₆₄ alloy membrane has been proposed. The membrane was found to be tough even in a hydrogen atmosphere and permeable only to hydrogen. In this study, a hydrogen separation module consisting of four amorphous Zr₃₆Ni₆₄ membranes has been developed to demonstrate practical usefulness of amorphous alloy membranes.
Amorphous Zr₃₆Ni₆₄ membranes were prepared by rapid quenching from the melt. On both sides, 100 nm Pd was coated using radio frequency sputtering to facilitate hydrogen dissociation and recombination on the surface. Thus prepared four membranes were aligned parallel. Spacers and metal gaskets were inserted between membranes. The most outer spaces and the space between the second and third membranes were permeation sides. Feed sides are those between the first and second, and the third and forth membranes. As a feed, a mixture simulating methanol reformed gas was used. The composition was 75% H₂, 23% CO₂ and 2% CO. The permeation side was atmospheric. No sweep gas was employed. Permeation rate was measured using two mass flow meters; one was for high flow rate and the other for low flow rate.
The module was confirmed to be successfully assembled without leakage. Using this module, pure hydrogen was obtained as effluent from the permeation side. The 82.7% recovery and 31.7 mL(STP)/min were attained in separation from dry gas mixtures simulating methanol reformed gas.