An experimental and modeling study of the oxidation of acetylene in a flow reactor

Acetylene is a hydrocarbon of significance in a variety of processes. It is an intermediate species during combustion processes and it is recognized as one of the most important soot precursors. Despite the large number of studies carried out in the past decades in relation to acetylene conversion in a variety of reactors (shock tubes, flames, and jet-stirred reactors) and operating conditions (from rich to lean environments, at different temperatures and pressures), the conversion of acetylene is not yet well described. An experimental and theoretical study of the oxidation of acetylene at atmospheric pressure in the temperature range 700–1500 K, and from fuel-rich to significantly fuel-lean conditions, has been performed. The experiments were conducted in an isothermal quartz flow reactor and the influence of the temperature and stoichiometry (by varying the O2 concentration for a given C2H2 initial level) on the concentrations of C2H2, CO, and CO2 has been analyzed. A reaction mechanism based on the model of Glarborg et al. [Combust. Flame 115 (1998) 1–27] for hydrocarbon/NO interactions, updated by Glarborg et al. [Combust. Flame 132 (2003) 629–638], and the model of Skjøth-Rasmussen et al. [Proc. Combust. Inst. 29 (2002) 1329–1336] for benzene formation, using methane as the initial hydrocarbon, has been used for calculations. The results show the oxidation regime of acetylene for different air excess conditions and the model developed allows a fairly good description of the experiments made. The experimental results are analyzed in terms of detailed chemistry and the main issues are discussed. The model here used should be further included in more detailed kinetic schemes and models developed to describe not only hydrocarbon conversion but also soot formation.