Reaction kinetics of dimethyl ether. I: high-temperature pyrolysis and oxidation in flow reactors

Dimethyl ether reaction kinetics at high temperature were studied in two different flow reactors under highly dilute conditions. Pyrolysis of dimethyl ether was studied in a variable-pressure flow reactor at 2.5 atm and 1118 K. Studies were also conducted in an atmospheric pressure flow reactor at about 1085 K. These experiments included trace-oxygen-assisted pyrolysis, as well as full oxidation experiments, with the equivalence ratio (φ) varying from 0.32 ≤ φ ≤ 3.4. On-line, continuous, extractive sampling in conjunction with Fourier Transform Infra-Red, Non-Dispersive Infra-Red (for CO and CO₂) and electrochemical (for O₂) analyses were performed to quantify species at specific locations along the axis of the turbulent flow reactors. Species concentrations were correlated against residence time in the reactor and species evolution profiles were compared to the predictions of a previously published detailed kinetic mechanism. Some changes were made to the model in order to improve agreement with the present experimental data. However, the revised model continues to reproduce previously reported high-temperature jet-stirred reactor and shock tube results.