Reaction of methanol to olefin using a membrane contactor on a silica substrate

•High olefins selectivity was obtained through the two-layer membrane contactor.•The C3H6/C3H8 selectivity was 236.•No need for further separation of C3H6 and C3H8.•The porous silica substrate was the key for the high selectivity.•The silica substrate improved the growth rate of the membrane. A MFI zeolite membrane was synthesized on a porous silica substrate. The defect-free MFI zeolite membrane was synthesized via a secondary growth method using seed crystals (Si/Al = 20) on a silica substrate in a parent gel of Si/Al = 100. The silica substrate prevented the dissolution of the seed crystals during the synthesis to promote the MFI zeolite membrane synthesis. The MFI zeolite membranes were employed for a contactor-type reactor for methanol-to-olefins (MTO) reactions to produce olefins, such as propylene. The methanol conversion was 99.9% with the selectivity of ethylene - pentene at 91.5% for the permeate side of the membrane contactor. The propylene selectivity was high at 48.5% with the C3H6/C3H8 ratio at 236.