Monolithic Fiber@HZSM-5Core-shell Catalysts For Methanol-to-propylene

In recent years the methanol-to-propylene (MTP) has been attracting particular attention as an alternative route for propylene production from non-petroleum sources such as coal, natural gas and biomass. ZSM-5zeolite-based catalysts have been extensively studied to orient product selectivity toward propylene and to further improve the catalyst stability, although Lurgi’s MTP process has been industrially demonstrated. Up to now, most attention has been focused on modification of the ZSM-5zeolite, such as proper tuning of the acidity (strength and density), size-and/or morphology-controllable synthesis and hierarchical design of pore structure.Microstructured catalyst, with substantial potential for significant improvement of catalytic performance, has now attracted widespread interests in heterogeneous catalysis by taking advantages of improved hydrodynamics and enhanced heat/mass transfer. Herein, we present a hierarchical3D pore ZSM-5catalyst engineered from micro-to macro-scales. Such microstructured design exhibits dramatic selectivity and stability improvement in MTP process in comparison with purely microporous zeolite powder, by nature, due to the increase of the propagation of olefin methylation/cracking cycle in methanol-to-hydrocarbon (MTH) catalysis. The microstructured fiber@HZSM-5core-shell catalyst is stable for at least210h while the maximum propylene selectivity of43%is obtainable with C2-C4light olefins selectivity of68%at450℃and weight hourly space velocity of1h-1, using30vol%methanol in N2. In contrast, the HZSM-5powder catalyst delivers only30%(max.) selectivity to propylene and <60%selectivity to C2-C4olefins under identical conditions while being stable for only60h.