Effect of postflame injection of fuel on the destruction of chlorinated hydrocarbons and the oxidation of NO

Postflame injection of fuel has been proposed as a means of reducing chlori nated hydrocarbons (CHCs) in a combustion exhaust. In this study, the effec ts of this strategy on CHCs and NOx are investigated. A small amount of fue l, such as CO or CH3OH, has been injected into the postflame region from a turbulent combustion-driven flow reactor to assess its effect on the destru ction of two CHCs (CH3Cl and C2H5Cl) and simultaneously, the oxidation of N O to NO2. The results suggest that this strategy is effective only in certa in conditions. There is an optimal temperature similar to 1050 K,where NO i s most effectively converted to NO2. Adding fuel to the postflame region in creases the concentrations of both HO2 and OH radicals, but temperature is the key factor in determining which radical will dominate the reaction path way. For the destruction of CHCs, attack by OH is the major destruction rou te, with T > 1200 K desired. For NO oxidation, the HO2 radical is the key s pecies, and lower temperatures are necessary. (C) 1999 by The Combustion In stitute.