A kinetic model to predict the catalyst lifetime in methanol to olefins conversion

The kinetics of deactivation of zeolite and zeotype catalysts in the conversion of methanol to olefins (MTO) was studied. A three-lump autocatalytic reaction network was considered for methanol conversion reactions. The reversible deactivation rate was considered to be single-lump and first-order in reactant concentration and catalyst activity. A correlation was developed for dimensionless catalyst lifetime as a function of a first Damköhler number and dimensionless rate constants ratio. It was used to relate the catalyst lifetime to methanol concentration in the feed, space velocity, crystallite size, and acidity of the catalyst in a fixed-bed reactor. The model predictions were tested against the published experimental data and favourable agreements were observed. The findings of this work can be used for optimizing reaction conditions to achieve maximum cumulative yield of olefins.