Separation of alkenes with organic and inorganic composite membranes

Abstract

In this study the separation of two alkenes, ethene and butene, which have similar physical properties, was attempted for industrial gas purification. Using both inorganic (ceramic and zeolite NaA) and polymeric (Teflon AF 2400) coated ceramic membranes, a mixture of 70 % ethene and 30 % butene was separated. Both membranes showed promising single gas permeation, where the best inorganic ideal selectivity (α = 9), was obtained for the NaA coated ceramic membrane. The Teflon AF 2400 coated ceramic membrane had an ideal selectivity of 31. For the binary mixture, the NaA coated ceramic membrane was however not able to separate the mixture satisfactorily, probably due to intercrystalline boundary diffusion. The Teflon coated membrane yielded a selectivity o 4 with a permeate permeance of 1.98×10-3 mol.s-1.m-2.bar-1