PROPARGYL-TYPE RADICALS AS PRECURSORS FOR POLYCHLORINATED AROMATIC HYDROCARBONS DURING INCINERATION

摘要

A gas-phase mechanism for the formation of polychlorinated benzene, in systems where chlorine concentration need not be high, is presented. The key features are the quenching and mixing of lean and rich mixtures and the involvement of propargyl radicals as a key intermediate. It is dependent on the resistance of this radical to oxidation and the formation of chlorine in lean mixtures as a result of the oxidation of HC1. Results are derived on the basis of simulation studies using data on the combustion and chlorination of small hydrocarbons. Carbon monoxide and hydrogen in the effluent stream catalyze the release of chlorine from HC1. These results may have implications on dioxin formation mechanisms since they suggest that even in the absence of surface processes there may be a residual contribution purely from gas-phase reactions.