Laminar flame speeds and oxidation kinetics of tetrachloromethane

The laminar flame speeds of blends of tetrachloromethane (CCl₄) with methane in air at room temperature and atmospheric pressure were experimentally determined using the counterflow twin-flame technique, varying both the amount of CCl₄ in the fuel and the equivalence ratio of the unburned mixture. Flame speeds were measured for stoichiometric mixtures with CCl₄-to-CH₄ ratios between 0 and 0.429 by volume and for equivalence ratio ranges of 0.7-1.3 and 0.7-1.2 for CCl₄-to-CH ₄ ratios of 0.053 and 0.200, respectively. Comparison between the present experimental results and the previous data of CH₃Cl-, CH ₂Cl₂-, and CHCl₃-CH₄-air flames demonstrates the dominant influence of the atomic Cl-to-H ratio on the propagation rate of laminar flames with chlorinated methane addition. A detailed kinetic model previously employed for CH₃Cl, CH₂Cl ₂, and CHCl₃ combustion was expanded to include additional pathways pertinent to tetrachloromethane combustion. Numerical simulation shows that this model predicts the laminar flame speeds reasonably well. Carbon flux and sensitivity analyses indicate that the oxidation kinetics of CH₄ flames doped with CCl₄ are essentially the same as those doped with other chloromethanes.