ZSM-5 zeolite coatings on perlite support for MTO application

Abstract

Abstract ZSM-5 zeolite crystals were grown via an in situ hydrothermal synthesis on perlite supports. In this study, cheap perlite mineral, which mainly contains SiO2 and metal oxides (Al2O3, CaO, MgO), was used as aluminum source and support material for binderless zeolite crystals growth. Hence, this synthesis strategy neither needs the introduction of Al, nor support surface functionalization steps, which may diminish the cost. Besides, the highly porous structure and the big particle size of ZSM-5/perlite composites are beneficial to reduce the pressure drop along the catalyst bed, rendering easier the heat and mass transfer of the products. In addition, the influence of different particle sizes (4–3, 3–1.5 and 1.5–0.5\xa0mm) and quantities (1–3\xa0g) of ZSM-5/perlite without any further modification were successfully evaluated in the Methanol-To-Olefins reaction (MTO). An optimized ZSM-5/perlite structured catalyst exhibited a high stability at full methanol conversion during 14\xa0h on stream, along with a 80% selectivity towards light olefins at 475\xa0°C. In addition, this catalyst still exhibited an excellent catalytic activity at relatively low temperature (350\xa0°C), the methanol conversion remaining 96% after 28\xa0h on stream. Finally, the conversion was maintained at 95% during 8\xa0h on stream at WHSV\xa0=\xa08\xa0h−1 with a propylene selectivity of 38%.