Experimental Study On The Mechanism And Inhibition Of Synthesis Of PCDD/Fs In Municipal Waste Incinerators

Incineration technology is one of the main municipal solid waste(MSW) disposal measures introduced in the world. Formation mechanism and controlling technology of dioxins in MSW incineration is one of the very active fields in modern environmental research. Relying on the Natural Science Foundation of Tianjin,China (No.09JCYBJC08100), this study gives synthesis mechanism of dioxins affected by the content of oxygen and the inhibitor additives, which are the foundation of controlling technologies of dioxins from MSW incineration for the future.First,the origin,physical and chemical characteristics and risk of dioxins is presented in the paper.And information of dioxins fomation and control in MSW incineration is introduced systematically. The method of the dioxin sampling is built.Then, the laboratory-scale studies on the mechanisms of MSW incineration were conducted in a self-developed batch system and the dioxins was absorbed by the glass fiber and XAD-2 resin. The influences of operational conditions such as different oxygen concentrations and different dioxin inhibitor added were investigated.Finally, the samples were detected by Enzyme immunoassay (EIA) and High-resolution chromatography and mass spectrometry method (HRGC / HRMS). The results showed there was a positive correlation between oxygen content with dioxins levels and O2 is the main oxygen source of the de novo synthesis. However, when the oxygen content higher than 33%, dioxins levels was reduced because of high combustion efficiency. The inhibition rate of adding S and CaO can exceed 80% , and adding CaO can reduce dioxins levels more effectively. Also there was a positive correlation between chlorine content with dioxins levels, so controlling the chlorine of MSW also can inhibit the dioxins effectively.