Modeling of Reaction and Deactivation Kinetics in Methanol-to-Olefins Reaction on SAPO-34

Abstract

A new kinetic model is proposed for the methanol-to-olefins (MTO) reaction over SAPO-34. The resulting products in this model are divided into 7 lumps: methane, ethylene, propylene, butene, propane, C4, and C5+. The deactivation kinetics of the MTO reaction is studied based on the proposed 7-lump kinetic model. The model is based on the assumptions that all reaction steps are first-order and the active catalyst reduction is proportional to the conversion. The kinetic parameters were determined using experimental data measured in a fixed bed reactor by use of a genetic algorithm. By regarding the deactivation of SAPO-34 as the loss of the active catalyst, the deactivation constant a is the only intrinsic parameter required to represent the effect of catalyst deactivation on the conversion and product yields with time on stream. This approach is effective for modeling complex deactivation kinetics in MTO. The results illustrate that the proposed model gives a reasonable representation of the experimental data.