2024-03-28T23:11:25Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/510512022-11-17T02:08:08Zhdl_2115_20045hdl_2115_139Kinetics of n-hexane cracking over ZSM-5 zeolites : Effect of crystal size on effectiveness factor and catalyst lifetimeKonno, HirokiOkamura, TakuyaKawahara, TakahitoNakasaka, YutaTago, TeruokiMasuda, TakaoNano-zeoliteZSM-5NaphthaCatalytic crackingKineticThiele modulus571The catalytic cracking of n-hexane over ZSM-5 zeolite (MFI-type zeolite, Si/Al = 150 and 240) catalysts was examined at reaction temperatures ranging from 823 to 923 K under atmospheric pressure. The reaction rate constants and activation energies of n-hexane cracking over ZSM-5 zeolites with various crystal sizes and Si/Al ratios were evaluated. The catalytic cracking of n-hexane was first order with respect to the n-hexane concentration, and the activation energies of n-hexane cracking over ZSM-5 zeolites were found to be approximately 123-128 kJ mol^[-1]. Compared with the macro-sized zeolite, the nano-sized zeolites exhibited high n-hexane conversion with stable activity for 50 h. This is because the cracking reaction with nano-sized zeolite proceeded under reaction-limiting conditions, whereas the reaction with macro-sized zeolite proceeded under transition conditions between reaction- and diffusion-limiting conditions. As a result, the application of nano-zeolite to the catalytic cracking of n-hexane was effective and gave light olefins with high yield and excellent stable activity.Elsevier B.V.Journal Articleapplication/pdfhttp://hdl.handle.net/2115/51051https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/51051/1/CEJ207-208_490-496.pdf1385-8947Chemical Engineering Journal207-2084904962012-10-01enginfo:doi/10.1016/j.cej.2012.06.157author