The influence of precursors on the induction period and transition-regime of dimethyl ether conversion to hydrocarbons over ZSM-5 catalysts

Omojola, T; Lukyanov, DB; Cherkasov, N; Zholobenko, V; van Veen, AC

Abstract

ZSM-5 catalysts were subjected to step response cycles of dimethyl ether (DME) at 300 °C in a temporal analysis of products (TAP) reactor. Propylene is the major olefin and displays an S-shaped profile. A 44-min induction period occurs before primary propylene formation and is reduced upon subsequent step response cycles. The S-shaped profile was interpreted according to induction, transition-regime and steady-state stages to investigate hydrocarbon formation from DME. The influence of precursors (carbon monoxide, hydrogen, dimethoxymethane, and 1,5-hexadiene) was studied using a novel consecutive step response methodology in the TAP reactor. Addition of dimethoxymethane, carbon monoxide, hydrogen or 1,5-hexadiene reduces the induction period of primary olefin formation. However, while dimethoxymethane, carbon monoxide and hydrogen accelerate the transition-regime towards hydrocarbon pool formation, 1,5-hexadiene attenuates it. Heavier hydrocarbons obtained from 1,5-hexadiene compete for active sites during secondary olefin formation. A phenomenological evaluation of multiple parameters is presented.

Citation

Omojola, T., Lukyanov, D., Cherkasov, N., Zholobenko, V., & van Veen, A. (2019). The influence of precursors on the induction period and transition-regime of dimethyl ether conversion to hydrocarbons over ZSM-5 catalysts. Industrial & Engineering Chemistry Research, 16479-16488. https://doi.org/10.1021/acs.iecr.9b03344

• Acceptance Date: Aug 13, 2019
• Publication Date: Sep 11, 2019
• Journal: Industrial & Engineering Chemistry Research
• Print ISSN: 0888-5885
• Publisher: American Chemical Society
• Pages: 16479-16488
• DOI: https://doi.org/10.1021/acs.iecr.9b03344
• Keywords: Methanol, Methanol-to-olefins, ZSM-5, Dimethyl Ether (DME), Temporal Analysis of Products; (TAP) reactor, primary olefins, nucleation kinetics, dimethoxymethane (DMM), diene,; transition-regime, induction period, hydrocarbon-pool, multi-parameter space ev
• Publisher URL: http://doi.org/10.1021/acs.iecr.9b03344