Mass-production of tubular NaY zeolite membranes for industrial purpose and their application to ethanol dehydration by vapor permeation

A fabrication method for tubular NaY zeolite membranes with 80 cm long for industrial purpose has been applied in mass-production to synthesize 99 membrane samples using two types of synthetic solutions with Al2O3:SiO2: Na2O: H2O = 1: 10: 14:800 and = 1:20:14: 1000. Sufficient reproducibility for industrial purpose with high membrane performance in mass-production were observed by pervaporation at 75 C in a feed mixture of water(10 wt.%)/ethanol(90 wt.%), resulting in the average flux (1 - sigma) and separation factor of 8.1 kg m(-2) h(-1) (1.5)and 220 for the SiO2-rich synthetic solution and those of 9.9 kg m(-2) h-1 (1.3) and 190 for the SiO2-poor solution, respectively. Dehydration of hydrous ethanol by vapor permeation for the present membranes was studied at 90-110 degrees C to investigate an applicability of these membranes to ethanol purification. The ethanol products with concentration up to 98.5 wt.% and with 96.1 wt.% could be obtained at 110 degrees C by production rates at 5 kg h(-1) and 20 kg h(-1), respectively. It is also confirmed that concentration polarization could limit the permeation fluxes through the present high-performance membranes for the feed flow rates at 5.5-22 kg h(-1) with the Reynolds number of 5000-20,000. (c) 2008 Elsevier B.V. All rights reserved.