Ceramic hollow fiber membrane distributor for heterogeneous catalysis: Effects of membrane structure and operating conditions

Abstract

A ceramic hollow fiber membrane distributor was proposed for the micro-scale distribution of reactants in heterogeneous catalytic reaction. To evaluate the feasibility and the performance of the ceramic hollow fiber membrane based reactant distribution, phenol hydroxylation with hydrogen peroxide (H2O2) over TS-1 solid catalysts was selected as a model reaction. The effects of membrane structural parameters of ceramic hollow fiber membrane on the micro-scale distribution and the reaction selectivity were studied in detail. The influence of operation conditions such as hydrogen peroxide flow rate, stirring rate and phenol/H2O2 molar ratio on the membrane distribution process was discussed. The ceramic hollow fiber membrane with small pore size and proper gradient in the pore structure was demonstrated to have a promotion effect on the reaction selectivity, which indicated its ability to generate uniform droplets in micro-scale. In addition, the increase of H2O2 flow rate and/or stirring rate can result in an improvement of reaction selectivity. Because of its controllable structure, high chemical stability and high packing density, the ceramic hollow fiber membrane distributor has potential for widespread applications in heterogenous catalysis.