Effects of Enhancing Micromixing on Nucleation/Crystal Growth Process and Material Properties of Zeolite

Abstract

Hierarchical (micro/mesopore) ZSM-5 zeolites were hydrothermally synthesized with enhancing micromixing of the high viscosity reaction system in a rotating packed bed (RPB). Herein, the effects of four operating processes with different micromixing intensity on nucleation/crystal growth process as well as properties of ZSM-5 zeolites were investigated. Results indicated that enhancing micromixing by RPB in the zeolite synthesis could facilitate the formation of Al sites and shorten the nucleation and crystallization period. ZSM-5 samples prepared by the RPB premix process exhibit hierarchical structure, smaller average particle size, more uniform particle size distributions, larger specific surface areas, higher catalytic stability as well as more Brønsted and Lewis acid sites. While adopting the prepared ZSM-5 zeolites with RPB premix for catalyzing C4-olefin cracking reaction, the conversion of C4-olefin and yield of propylene were higher than that obtained by traditional stirring tank reactor premix.