A Model to Analyze Formation of Dioxins in the High Temperature Regions of Municipal Solid Waste Incinerators

Abstract

Polychlorinated dibenzo-p-dioxins (PCDD) can be formed in significant amounts in municipal solid waste incinerators. Earlier attempts at modeling their formation proposed that chlorobenzenes (CB) and chlorophenols (CP) could be precursors to PCDD formation. Most modeling studies have been largely confined to the lower temperature regions of the incinerator (450–550 K or 177–277°C). But incinerator data seem to indicate that PCDD are also formed in the region between the secondary combustion chamber and the particle collection device, a region that might be represented by a temperature range of 450–1150 K (177–877°C). PCDD formation in this region can be predicted by the same model used for the lower temperature region by including a temperature dependence for the surface coverage of fly ash particles in the model. The effect of particle size is also discussed.