Catalytic synthesis of C$_2$-C$_4$-alkenes from dimethyl ether

TL;DR

This study investigates how the volumetric velocity and reaction conditions affect the catalytic conversion of dimethyl ether to C2-C4 olefins using Zn-Zr-Cu/HSZ/Al2O3 catalysts, revealing optimal parameters for higher selectivity and yield.

Contribution

It demonstrates the impact of volumetric velocity and temperature on olefin selectivity and yield, providing insights for optimizing catalytic processes for dimethyl ether conversion.

Findings

Higher volumetric velocity reduces DME conversion and olefin selectivity.

Lower reaction temperatures increase ethylene and propylene selectivity.

Adjusting raw material composition alters olefin ratios.

Abstract

In the study, the effect of the volumetric velocity of the initial gaseous mixture on the catalytic properties of Zn-Zr-Cu/HSZ/Al$_2$O$_3$ in the conversion of dimethyl ether to olefins was studied. When the volumetric rate is increased by 5 times, the conversion of dimethyl ether decreases from 96.5 to 40.7 %, the total selectivity for C$_2$=-C$_4$=olefins decreases from 59.0 to 75.5 mas.%, at the same time, the yield of the by-products of the reaction - C$_2$ + paraffin is reduced. A decrease in the reaction temperature at the equal conversion of dimethyl ether leads to an increase in selectivity for both ethylene and propylene due to a decrease in the formation of methane and C$_2$+paraffin in the reaction products. Thus, in copper-containing zeolite catalysts, lower olefins than dimethyl ether provide higher conversion of raw material and higher selectivity of olefin formation (up to 90 mas. %.). Also, changing the initial raw material composition and regime parameters allows a significant change in the ratio of olefins to each other.