Industrial-scale 61-channel monolithic silicalite-1 membranes for butane isomer separation

Abstract

Developing energy-saving membrane and technology is important for the separation of hydrocarbon isomers to replace the energy-intensive distillation. Silicalite-1 membrane is a promising membrane material but difficult to be scaled up. In this work, separation performance of industrial-scale monolithic silicalite-1 membranes in term of actual butane mixtures has been reported for the first time. Each 61-channel monolithic membrane has effective area and surface-to-volume ratio of 0.2 m2 and 400 m2/m3, which are about 20 and 5.6 times higher than that of the common tubular one with the same length, respectively. Average n-butane/i-butane separation factor (34) of the industrial-scale membranes was even higher than or comparable to that of the reported small-area zeolite membranes. The influences of test parameters on permeances and separation factors of the membranes and the long-term stability were examined. Reynold numbers was used to correlate the concentration polarization (CP) with the reduction of separation performance. A solution was proposed to reduce the effect of CP. It suggests that the industrial-scale and high-performance monolithic silicalite-1 membranes are suitable for actual applications of butane separation.