Chemical Species and Temperature Profiles of Laminar Dichloromethane-Methane-Air Flames.I. Variation of Chlorine/ Hydrogen Loading

Abstract

Gas samples have been extracted from laminar atmospheric pressure CH₂ CI₂-CH₄ -air flat flames using uncooled quartz probes with 0.05 to 0.10 mm orifices. The samples ( 50torr total pressure) were analyzed by gas chromatography for a number of major C₁ and C₂ hydrocarbons, chlorinated hydrocarbons and CO, CO₂, O₂ CH₄ N₂and H₂ Temperatures were obtained throughout the reaction zone and into the postflame region using Pt-Pt (13 percent Rh) uncoated thermocouples with typical bead diameters of 0.15 mm. Measurements of species concentrations (major and minor stable products) along with temperatures are provided as a function of vertical distance above the burner for three separate flames with Cl/ H ratios of 0.060, 0.33 and 0.72 for φ 0.80. All intermediate species (with the exception of CHC1₃) are observed to fall below detectable limits when the CH₂ CI₂ concentration is less than 1 percent of its initial value. Peak values of major intermediates are presented as a function of Cl/ H ratio. In addition, plots of major intermediates are provided as a function of Cl/ H ratios to observe the effect of chlorine loading. The results provide a better understanding of the fundamental combustion processes which occur during the incineration of CH₂ C1₂ and similar chlorinated methanes.