Simulation of methanol-to-olefin reaction over SAPO-34 catalysts with different particle sizes: Formation of active sites and deactivation

Abstract

Conversion profiles of methanol-to-olefin (MTO) reaction over SAPO-34 catalysts with different particle sizes were simulated using two kinetic models. The MTO reaction was assumed to consist of three steps: the formation of hexamethylbenzene (HMB), the production of lower olefins over HMB and the further condensation of HMB to polyaromatic hydrocarbons. To reflect the effect of particle size on the MTO reaction, only the space near the external particle surface was considered to be available for HMB formation in Model I, whereas an effectiveness factor and a deactivation function were introduced in Model II. The simulated conversion profiles of the MTO reaction by both models successfully confirmed the presence of an induction period and deactivation, but Model II showed a better agreement between the experimental and simulated results because of its inclusion of the deactivation function and its consideration for the gradient of methanol concentration.

Recent modifications of MCM-22 and MOR zeolite in MTO reaction: A review

“…However, the process of HMB formation necessitates an induction period for the creation of additional active species. Further condensation of HMB molecules to polyaromatic hydrocarbon (PAH) via alkylation ultimately results in catalyst deactivation [25].…”