We proved that the disposition of tandem fixed-beds of ZSM-5 with SAPO-18 catalysts could decrease the deactivation of the second catalytic bed during the methanol-to-olefins (MTO) reaction. For this purpose, we prepared two catalysts based on ZSM-5 zeolite and SAPO-18 zeotype; characterized them using XPS, XRD, 29Si NMR, N2 physisorption, NH3-TPD and FTIR; tested them individually, in mixed or tandem forms using a fixed-bed reactor or in-situ reactors monitored with UV-vis or FTIR spectroscopies; and characterized the catalyst during the reaction or after it. The catalytic beds (mixed or tandem) did not offer any significant enhancement or synergetic effect in product selectivity. However, the catalytic lifetime of the second bed in the tandem catalytic beds (particularly if that is made up of SAPO-18 catalyst) was prolonged because this bed receives less oxygenates (methanol and dimethyl ether) and more water, which slows down the deactivation of the second catalytic bed.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was possible thanks to the financial support of the Ministry of Economy, Industry and Competitiveness of the Spanish Government (Project CTQ2016-79646-P, co-founded with ERDF funds) and the Basque Government (Project IT748-13, IT912-
16). J.V. is thankful for his fellowship granted by the Ministry of Economy, Industry and Competitiveness of the Spanish Government (BES-2014-069980). The authors are thankful for technical and human support provided by IZO-SGI SGIker of UPV/EHU and
European funding (ERDF and ESF).