Abstract
Separation properties of mordenite membrane for water-methanol-hydrogen mixtures were studied in the temperature range from 150 to 250°C under pressurized conditions. Mordenite is a kind of large pore zeolites with a pore diameter of 0.65 x 0.70 nm. Mordenite membrane was prepared on the outer surface of a porous alumina tubular support by a secondary-growth method. We found that water was selectively permeated through the membrane. The separation factors of water/hydrogen and water/methanol were 49 and 73, respectively, at 250°C. When only hydrogen was fed at 5 atm, its permeance was as low as 10-9 mol m-2 s-1 Pa-1 up to about 220°C, possibly suggesting that water pre-adsorbed in the micropores of mordenite hindered the permeation of hydrogen. The hydrogen permeance, however, dramatically increased to 6.5 x 10-7 mol m-2 s-1 Pa-1 at 230°C and reached to 1.4 x 10-6 mol m-2 s-1 Pa-1 at 250°C owing to the formation of cracks in the membrane. It was, however, found that the membrane was thermally stabilized in the presence of steam and/or methanol.
