Zeolite/cellulose acetate mixed matrix membranes for olefin/paraffin separations

Abstract

Membranes for olefin/paraffin separations are important in today’s chemical and petrochemical industry due to lower capital cost and lower energy consumption. Hence, a new type of mixed matrix membrane (MMM) has been developed for these separations. NaX-zeolite, AgX-zeolite and silicalite were used as adsorbent incorporated into cellulose acetate (CA) polymer for making MMMs. They were prepared by solution-casting method and characterized for the morphologies of MMMs by scanning electron microscopy. Then, they were tested for ethylene/ethane and propylene/propane separations by using the membrane-testing unit. For a comparison purpose, CA membrane was also prepared and tested for the above separations. It was found that CA membrane was selective for ethylene over ethane and propylene over propane. For the MMMs, 20% silicalite/CA MMM was selective for propylene over propane. However, NaX-zeolite/CA and AgXzeolite/CA MMMs were reverse selective for olefins over paraffins.