Synergistic effect of Fe and Ga incorporation into ZSM-5 to increase propylene production in the cracking of n-hexane utilizing a microchannel reactor

Abstract

In the present study, the effect of various amounts of Fe and Ga in the catalytic cracking of n-hexane in a microchannel reactor was investigated using experimental design by the D-optimal method. Nano zeolites incorporated with Fe and Ga metals were synthesized in a fluorine environment to investigate the synergistic effect of the metals on the textural and acidic properties of the catalysts, which ultimately improved the performance of the synthesized catalysts in the efficient production of light olefins, in particular propylene. Three synthesis parameters including the Si/Al, Si/Fe and Si/Ga ratios were considered as the main factors to determine the optimal conditions for obtaining the maximum conversion of n-hexane, yield of light olefins, and P/E ratio and minimum yield of alkanes as the responses. In sample FeGa-1, the P/E ratio reached 3.97, indicating the significant effect of the substituted metals in improving the desirable routes for propylene production. According to the results of the acidic properties, Fe, Al and Ga increased the number of total acid sites and the strengths of strong and weak acid sites, respectively. In addition, according to the results obtained from sample FeGa-7, the synergistic effect of Fe and Ga increased the number of weak acid sites.