Study on Catalytic Cracking of Cyclohexane to Produce Light Olefins

Catalytic cracking of cyclohexane(CHA) over ZSM-5, Beta, and USY zeolite catalysts was examined in a fixed fluidized bed reactor(ACE) at 773 K. The adsorption of cyclohexane in ZSM-5, Beta, and USY catalysts was investigated by IR spectroscopy. The IR results demonstrated that the zeolite structure has a remarkable influence on adsorption. Beta zeolite has stronger adsorption of cyclohexane than ZSM-5 and USY zeolites. During the cracking of cyclohexane, path Ⅰ(cyclohexane →methycyclopentane →light olefins) and path Ⅱ(cyclohexane → cyclohexene → light olefins) were found as two important reaction pathways to produce light olefins. A mixture of ZSM-5 and Beta zeolites is better suited for path Ⅰ, and a combination of ZSM-5 and USY zeolites is suitable for path Ⅱ. When pathway Ⅰ and pathway Ⅱ had the same proportion in cyclohexane conversion, pathway Ⅱ would be a better choice for light olefins production.