Deactivation kinetics for the conversion of dimethyl ether to olefins over a HZSM-5 zeolite catalyst

Abstract A deactivation kinetic equation for the conversion of dimethyl ether (DME) to olefins (DTO process) has been established. The catalyst has been prepared with a HZSM-5 zeolite (SiO 2 /Al 2 O 3 ratio of 280) agglomerated with boehmite (mesoporous matrix of weak acidity). The experimental data have been obtained in an isothermal fixed bed reactor in a wide range of operating conditions: temperature, 573–673 K; space time, 0.2–6 g cat  h mol C −1 ; time on stream, 18 h; and different dilutions of DME (with He, methanol and water). The main cause of the catalyst deactivation is the coke deposition, being DME the principal precursor and the presence of water in the medium a key parameter in its attenuation. The kinetic model considers these effects and its use together with the kinetic model at zero time on stream results suitable to simulate the reactor over the whole range of operating conditions experimentally studied.