| Abstract
| - This research examined the potential for emissions ofpolychlorinated dibenzodioxin and dibenzofuran (PCDD/F)from industrial boilers that cofire hazardous waste. PCDD/Femissions were sampled from a 732 kW (2.5 × 106 Btu/h), 3-pass, firetube boiler using #2 fuel oil cofired with 2,4-dichlorophenol or 1,2-dichlorobenzene and a coppernaphthenate mixture. PCDD/F levels were significantlyelevated when improved combustion conditions (reducedcarbon monoxide, increased carbon dioxide) followed periodsof flame wall-impingement and soot formation/depositionon the boiler tubes. Boiler tube deposits became a sink andsource for PCDD/F reactants (copper and chlorine) andPCDD/F, resulting in continued formation and emissions longafter waste cofiring ceased. The role of deposits inPCDD/F formation makes emissions dependent on currentas well as previous firing conditions, resulting inuncertainty regarding prediction of emissions basedsolely on the type and rate of cofired hazardous waste.
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