Enhanced formation of dioxins and furans from combustion devices by addition of trace quantities of bromine

Past pilot-scale experimental studies have shown a dramatic increase in the formation of certain chlorinated products of incomplete combustion (PICs) caused by the addition of trace amounts of bromine (Br). Emissions of trich loroethylene and tetrachloroethylene, generated as PICs from the fuel-lean combustion of methylene chloride, were enhanced by up to 3 orders of magnit ude by introducing Pr in the form of methylene bromide at a constant haloge n molar input rate with a 1:10 Br/chlorine (Cl) molar ratio. The two chlori nated PICs in question are both potential ring growth precursors, which cou ld lead to enhanced formation of polychlorinated dibenzo-p-dioxins and poly chlorinated dibenzofurans (PCDDs/PCDFs). The experiments described in this paper expand on this earlier work by examining the effect of trace amounts of Br on the formation of PCDDs/PCDFs, in addition to other chlorinated, br ominated, and mixed bromo-chloro organic PICs. (C) 1999 Elsevier Science Lt d. All rights reserved.