A chemical kinetic study of the oxidation of dibutyl-ether in a jet-stirred reactor

摘要

The oxidation of dibutyl-ether, a potential lignocellulosic biofuel was studied in a jet-stirred reactor. Fuel-lean, stoichiometric and fuel-rich mixtures were oxidized at a constant fuel mole fraction (1000 ppm), at temperatures ranging from 470 to 1250 K, pressures of 1 and 10 atm, and constant residence time (70 and 700 ms, respectively). The mole fraction profiles obtained through sonic probe sampling, gas chromatography and Fourier transform infrared spectrometry were used to develop a detailed kinetic mechanism for the oxidation of DBE. The carbon neighboring the ether group was found to be the most favorable site for H-abstraction reactions and the chemistry of the corresponding fuel radical drives the overall reactivity. The fuel concentration profiles indicated strong low-temperature chemistry at both pressures: two negative temperature coefficient regions were observed, notably on the 10 atm experiments. This unusual behavior was investigated by means of a rate of production analysis using the mechanism developed in this work. This analysis showed that the low-temperature reactivity stems from the low-temperature chemistry of the fuel and of smaller species such as C4H9 which are triggered at different threshold temperatures. The proposed mechanism shows good performances for representing the present experimental data, as well as ignition delay time and flame speed data available from the literature. (C) 2017 The Combustion Institute. Published by Elsevier Inc. All rights reserved.