Synthesize Of Silicalite-1 Membrane And Application For Pervaportion Of ETOH/Water Mixture

Energy problem had became an important issue that can not be ignored in contemporary society, as an green energy, ethanol has great practical significance in alleviating nowadays energy shortage and air pollution. Pervaporation as a new separation process had many advantages of having simple equipment, low energy consumption and high efficient. Sillcalite-1 zeolite membrane with high hydrophobicity had a excellent effect on separation of ethanol/water. In my thesis, Silicalite-1 zeolite membrane which was synthesized by two stage temperature-varied hydrothermal synthesis in porous stainless steel andα-Al2O3 carrier, chatacterized by means of SEM,XRD and gas permeation. I also had a research on its pervaporation performance to ethanol/water.1. This article studied the impact of the different synthetic temperature, reaction time, OH-/Si in the content of synthetic liquid and different carriers on the synthesis of Silicalite-1. The high synthetic temperature and long reaction time will increase the diameter of Molecular-Sieves crystal and the thickness of membranes.But the low synthetic temperature and short reaction time will cause the surface of carriers can not be fully growed and then many defects will appear. The increase of OH-/Si in the content of the synthetic liquid will diminish diameter of molecular-sieves crystal and increase the density the membranous layer.2. It also studied the gas permeability of the synthetic molecular-sieves membranes on different synthetic condition and different carrier. With temperature varied from 140℃to 200℃, the surface morphology and the air permeability of the synthetic membrane reach its best state under the 160℃,the permeation flux of H2 is 9.86×10-7mol·Pa·1-s·1·m-2, H2/N2 reach 5.39; As synthetic time extended from 12h to 72h,24h reaction time is the best properties of synthetic membrane, the permeation flux of H2 was 10.91×10-7mol·Pa-1·s-1·m-2, H2/N2 reached 5.27; with OH-/Si is different from 0.05 to 0.2, when OH-/Si is 0.2, zeolite membrane at its best property, the permeation flux of H2 is 9.27×10-7mol·Pa-1·s-1·m-2, while H2/N2 reached 5.50; in the aspect of the ideal permeation flux and separation factor,the membrane which take the porous stainless steel as the carrier is superior to those generated on theα-Al2O3 ceramic membrane carrier.3. To observe and study the law of the pervaporation performance of synthetizing Silicalite-1 zeolite membrane to ethanol/water with the change of feed temperature and concentration respectively in the carrier of the porous stainless steel andα-Al2O3 ceramic. Take the carrier of the porous stainless steel as an example, when feed temperature 50℃and concentration 3%, separation factor reached 36.654, the flux was 0.407Kg·h-1·m-2.under the same conditions,takeα-Al2O3 Ceramic tube as the carrier, its ceramic membrane separation factor was 31.973, the flux is 0.397.