2006 Volume 31 Issue 1 Pages 28-32
Hydrogen permselective silica membranes were prepared by using a counter diffusion chemical vapor deposition method. H2 permeances through silica membranes were over 8x10-8 mol m-2 s-1 Pa-1, and H2/N2 permeance ratios were over 500 at 873 K. Reproducibility of the silica membranes were 87%. Pore size of an alumina substrate was important parameter to obtain higher H2 permeances. H2 permeance was lager through a silica membrane deposited on a substrate having smaller pore size. Activation energies of H2 permeance through the silica membranes increased with increasing the deposition temperatures. However, the membranes prepared over 873 K were not stable under steam at 773 K. A 3 membranes module was employed for the simultaneous multi membranes deposition of silica layers. H2 permeance through the module was 5.0 x 10-8 mol m-2 s-1 Pa-1, and H2/N2 permeance ratio was 3200 at 873 K. The deposited silica membrane properties on the membrane module was similar to that deposited on a single membrane substrate.
