(340c) Development of Hitz Zeolite Membrane Dehydration System for Bio-Ethanol Production

Hitachi Zosen Corporation (Hitz) has been actively engaged in the developing of the zeolite dehydration membrane for the bio-ethanol production and solvents purification. NaA type and NaY type zeolite membrane elements with the size of 16 mm in diameter and 1150 mm in length have been successfully developed. The element composed of a Al2O3 porous support tube with a closed end and a zeolite thin film deposited on outer surface of the tube by a hydrothermal synthesis process. The element constitution is only inorganic material, which leads high durability performance. The performance of the membrane elements has been tested in pervaporation (PV) and vapor permeation (VP) condition for the feed of ethanol-water mixture. For example, it was found that the VP dehydration flux of NaA type zeolile membrane was 50 kg m-2 h-1 at the temperature of 130 degree centigrade and the feed of ethanol(90 wt%)/water(10 wt%), which was two times to seven times higher than that of previous reports. It was also found that the separation factor of Hitz NaA membrane was several thousand or more and this high selectivity can lead the high efficient dehydration system. The dehydration system using Hitz NaA membrane elements were adopted for the first commercial bio-ethanol plant with the capacity of 50,000 L/d in Japan, 2008. The system has been operated successfully more than one year and it is found that the bio-ethanol product purity is 99.9 to 99.95 vol% at the capacity of 50,000 to 53,000 L/d.