THE COMBUSTION OF MUNICIPAL SOLID-WASTE AND PCDD AND PCDF EMISSIONS - ON THE REAL SCALE THERMAL-BEHAVIOR OF PCDD AND PCDF IN FLUE-GAS AND FLY-ASH

The results obtained in an investigation on the real scale thermal behavior of PCDD and PCDF in flue gas and fly ash are reported. The sampling time of flue gas at about 300°C significantly affects dioxin and furan concentrations and fingerprints in the particulate, probably due to chlorination reactions. The lack of fingerprint evolution in the gaseous samples on passing through the boiler and ESP, seems to indicate the absence of gas phase reactions. Moreover, PCDD and PCDF concentrations in the gas phase at the post-combustion exit and at the stack inlet are of some ng/Nm3 and the fingerprints are also very similar. In the fly ash collected in the boiler, economizer and ESP, a progressive shift from lower chlorinated to higher chlorinated congeners is observed: possible mechanistic explanations are reported. © 1990.