Pyrolysis and catalysis of dimethyl ether in a flow reactor

Abstract

Dimethyl ether (DME) was an interesting alternative fuel for diesel and HCCI engines with the global energy crisis and growing environmental concerns. The DME pyrolysis was investigated experimentally from 700 K to 1220 K in a flow reactor. The concentration of DME and products has been detected by a gas chromatography with a thermal conductivity detector. In addition to methane, carbon monoxide, ethylene and ethane, methanol has been detected in present study. A kinetic mechanism for DME pyrolysis has been studied to analyze the pathways of methanol formation. The main routes of methanol formation were the H-atom abstractions by methoxy radicals, in which the dominant one was H-abstractions from DME molecules. The catalytic pyrolysis and catalytic oxidation of DME over γ-Al2O3 catalyst were investigated in the flow reactor from 300 K to 840 K. A large amount of hydrogen has been detected from DME catalytic pyrolysis and catalytic oxidation, both in which hydrogen was the dominatedfinal product. The excess O2 and the larger contact area with the catalyst contributed to the hydrogen production from DME catalytic oxidation.