Analysis of the deactivation of ZSM-5 catalyst during MTO reaction in a periodic operating fixed bed reactor

A set of methanol to olefins (MTO) reactions has been performed in a fixed bed periodic operating reactor with a low acidic ZSM-5 zeolite catalyst. The experimental set-up of the periodic reactor allows the operation in fast heating cooling cycles, therefore obtaining coke formed by distinct pathways. The conversion of oxygenates and yields of products have been analyzed for both conventional fixed bed and periodic operating reactor and the deactivated catalyst has been characterized by different methods and then compared to those obtained for the fresh catalyst. Our results show that periodic operation is a suitable option for extending the lifetime of the catalyst compared to the conventional steady operating MTO reaction. The stability increase is proportional to the length of the oscillation period. The analysis of the coke samples obtained with periodic operation combined with the information obtained by improved techniques such as catalyzed combustion of coke open a new approach to understanding the catalyst deactivation in MTO reaction.