四通道中空纤维 MFI 分子筛膜用于二甲苯异构体分离

MFI zeolite membranes were prepared on four-channel α-Al₂O₃ hollow fiber supports (7 cm) with high mechanical strength and high loading density by secondary growth method. The effects of synthetic time, operation temperature, partial pressure of raw material and purge gas flow rate on the membrane separation performance of xylene isomer were investigated. The results showed that the four-channel hollow fiber MFI zeolite membrane prepared by hydrothermal synthesis at 160℃ for 12 h possessed the better separation performance of xylene isomers. The separation factor of p-xylene/o-xylene was up to 878 at 150℃, partial pressure of raw material 2 kPa and purge gas flow rate 20 ml/min. PX permeance was 2.1×10^-8 mol·m^-2·s^-1·Pa^-1. Based on the optimized membrane preparation conditions, the MFI zeolite membranes were further prepared on the 27 cm long four-channel hollow fiber supports. An excellent p-xylene/o-xylene membrane separation performance was obtained, and the as-prepared membrane can run stably for more than 100 h for the separation of xylene isomer mixture. This study laid the foundation for promoting the batch preparation of hollow fiber MFI zeolite membranes and the technical innovation of traditional separation process.