CHLOROCARBON-INDUCED INCOMPLETE COMBUSTION IN A JET-STIRRED REACTOR

The chemistry leading to products of incomplete combustion, as affected by chlorocarbons, was studied by modeling data from a jet-stirred reactor, verifield experimentally to be at nearly perfectly-stirred conditions. Premixed, fuel-rich mixtures of C2H4, CH3Cl, and air were burned in a toroidal jet-stirred combustor. Instantaneous measurements of local temperature were obtained using laser Rayleigh scattering, and extractive probe sampling followed by gas chromatography was used to determine concentrations of stable species. Reactor temperature, and equivalence ratio (phi) were held constant, while the chlorine content was varied by modifying the C2H4, CH3Cl, and diluent N2 flows. The instantaneous temperature measurements showed that the reactor remains nearly perfectly-stirred, even to the point of blowout. A perfectly stirred reactor (PSR) model indicated that the principal effect of chlorine addition was that of inhibiting the burnout of CO to CO2, consistent with the experimental observation of increasing CO/CO2 ratio with increasing chlorine content. Burnout of CO was inhibited by depletion of OH in the presence of HCl by the reaction OH + HCl double line arrow pointing right H2O + Cl. In addition, consumption of fuel and initial intermediates was dominated by H abstraction reactions with Cl producing HCl. The HCl subsequently reacts with OH, H, and O radicals to produce Cl which reacts with the fuel but does not substantially participate in oxygen decomposition or subsequent reactions leading to final products. The depletion of OH, H, and O by reaction with HCl thus results in increased levels of intermediate hydrocarbons, oxygen and CO.