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.