Revisit the pathway and kinetics for transformation of light olefins over ZSM-5 modeling: Influence of steam-pretreatment

Abstract

Previous kinetic studies on light olefins transformation over ZSM-5 catalyst were carried out either with pristine zeolite powders (research catalyst), or with commercial catalysts (technical catalyst) as-received without steam pretreatment, meanwhile, a rational procedure to discern the reaction network was lacking, thus a gap inevitably existed between the kinetic model established and the industrial practice. Herein, we revisited the kinetics of light olefins (C3–C7) interconversion over the commercial ZSM-5 catalyst, and special attention was paid to the effect of steam treatment. Comparative analysis was performed between the pristine and the steam-treated catalysts in terms of acid property, catalytic activity, and deactivation behavior. With the help of Delplot analysis, a rational and reliable kinetic model was developed for olefins interconversion as simple as possible, and a temporal kinetic model for catalyst deactivation was also proposed. These models can provide kinetic foundations for design and retrofit of MTO or MTP reactors.