Changes of Homologue Profiles of PCDD/Fs in Waste Incineration in a Laboratory-Scale Fluidized-Bed Reactor

Abstract

Combustion experiments using a laboratory-scale fluidized-bed reactor were performed to elucidate the influence of chlorine content in wastes and combustion temperature on homologue profiles of poly-chlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) during incineration of model wastes with polyvinyl chloride or sodium chloride as a chlorine source and copper chloride as a catalyst. The experi-mental setup was carefully planned to obtain reliable data. In all experiments, the higher ratio of chlori-nation of PCDDs to PCDFs was obtained. As CO concentration in flue gas increased, the amount of PCDD/Fs increased and their homologue profiles were shifted toward higher chlorinated species. Such trends were more significant in PCDFs than PCDDs. The changes of the homologue profiles show that the major formation pathways are different between PCDDs and PCDFs. PCDDs could mainly form via materials that readily react with chlorine. The major formation pathways of PCDFs are strongly affected by combustion conditions.