Mechanistic insights into the conversion of dimethyl ether over ZSM-5 catalysts: A combined temperature-programmed surface reaction and microkinetic modelling study

نویسندگان

چکیده

The rates of adsorption, desorption, and surface reaction dimethyl ether (DME) to olefins over fresh working ZSM-5 catalysts with different Si/Al ratios (36 135) were decoupled using a combination temperature-programmed experiments microkinetic modelling. Transient reactor performance was simulated by solving coupled 1D nonlinear partial differential equations accounting for elementary steps during the induction period based on methoxymethyl mechanism zeolite catalyst axial dispersion convection in reactor. Propylene is major olefin formed, site-specific scaling relations between activation energies DME desorption barriers formation methyl propenyl are observed. Six ensembles sites observed maximum three adsorption/desorption adsorption/desorption/reaction sites. Barriers generally higher than catalysts. Activation propylene ca. 200 kJ mol?1 obtained, corroborating direct mechanistic proposals.

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ژورنال

عنوان ژورنال: Chemical Engineering Science

سال: 2021

ISSN: ['1873-4405', '0009-2509']

DOI: https://doi.org/10.1016/j.ces.2021.116620