Hydrogen separation from dry gas mixtures using a membrane module consisting of palladium-coated amorphous-alloy

Amorphous alloy membranes are anticipated as substitutes for expensive palladium membranes. Hydrogen separation modules consisting of four amorphous Zr36Ni64 membranes have been developed to demonstrate their practical usefulness. First, surface investigation showed that 50-mm-wide membranes are smoother on the surface and are therefore expected to be better in terms of sealing than 20-mm-wide membranes. A four-membrane module was assembled without leakage for 0.92 MPa inside to the atmospheric outside. 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 CO and CO2 containing a gas mixture simulating methanol reformed gas. Therefore, the practical availability of amorphous alloy membranes was demonstrated.

Permeation tests of a one-membrane module and a four-membrane module were performed at Two amorphous Zr36Ni64 membranes of different widths were prepared; their surfaces were investigated. Results show that 50 mm wide membranes were smoother than narrower membranes because of low Ar pressure during quenching. Therefore, wider membranes were used for hydrogen separation modules. The assembled modules were gas-tight from the inside to the outside: leakage was less than 0.018 mL (STP)/min for 0.92 MPa. Hydrogen separation from the gas mixture was investigated using assembled modules. The module performances were investigated in terms of a dimensionless number . The performance of four-membrane modules agreed with that expected from results of a one-membrane module. Using this module, 82.7% recovery for a 31.7 mL (STP)/min permeation rate was obtained. The permeated gas was over 99.999% pure hydrogen. Therefore, practical availability of amorphous alloy membranes was demonstrated.