中空纤维MFI/α-Al_2O_3分子筛膜的制备及其二甲苯分离研究

Preparation of MFI/α-Al_2O_3 hollow fiber zeolite membranes and its application to xylene separation

采用原位水热合成法在具有较高装填面积的α-Al2O3中空纤维支撑体上制备MFI分子筛膜.实验研究了膜合成时间及重复次数对膜质量的影响.结果表明,经过两次5h合成的中空纤维MFI分子筛膜具有良好的膜结构和较优的对二甲苯(PX)渗透选择性.同时,系统考察了操作温度和进料分压对膜性能的影响.结果显示,对于PX/OX(邻二甲苯)/MX(间二甲苯)(2∶1∶1)三元体系的分离,150℃时,PX/OX和PX/MX的分离因子分别可达174、79,PX的渗透性为3.7×10-9 mol/(m2·s·Pa).

MFI zeolite membranes were prepared on α-Alz 03 hollow fiber supports with high packed density by in-situ hydrothermal synthesis method. The influences of hydrothermal synthesis time and repeated times on the quality of the as-synthesized membranes were studied. It was observed that hollow fiber MFI zeolite membranes with excellent structure and para-xylene （PX） permseleetivity were fabricated by twice growth for 5 h. Meanwhile, the effects of operating temperature and feed partial pressure on membrane performance were investigated systematically. As a result, the PX/OX and PX/MX separation factor up to 174 and 79 with PX permeance of 3.7 × 10-gmol/（m2 · s · Pa） was obtained at 150 ＊C for a PX/OX/MX （2 ： 1 ： 1） ternary mixture.