At present

the emission of polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs)has hampered the application of combustion technology in waste clean treatment and waste to energy utilization.This study experimentally investigated the inhibition of PCDD/Fs formation from fly ash by ammonium sulfate and urea at different temperatures.Some key observations were reported.Both inhibitors had higher inhibition efficiency at a high temperature(650℃)than a low temperature(350℃)

while the production of PCDD/Fs at 650℃ was quite small; the main reduction of PCDD/Fs was from PCDFs

as well as

the most significant reduction of homologue was TeCDF at a low temperature(350℃)and OCDF at 650℃.In a full scale incinerator

the chemical additives injected at the high temperature section could enter the low temperature area and continued to inhibit dioxin formation

so it is necessary to do more work to evaluate different inhibitors for PCDD/Fs formation and figure out the optimal injecting temperature.