Study On Effects Of Chlorine Sources On Emission Of HCL And PCDD/Fs During Municipal Solid Wastes Incineration

Chlorine is one of the important elements that can cause secondary pollution. For its existence design, operation and maintenance of municipal solid wastes incinerators(MSWI) will be greatly influenced; moreover corrosion of super heaters and contamination of air will be realized by HC1 converted from chlorine. In addition, chlorine is also one of components of dioxins and it can affect the shift and distribution of heavy metal. This paper will focus on such hotspots as determination of chlorine content in representative MSW, the mechanisms of chlorine being converted into HC1 and the effects on dioxins formation. Some valuable conclusions have been drawn.Chlorine contents of the representative composition of MSW are quantitatively analyzed by using silver nitride volumetric analysis (SNVA) method, mercury thiocyanate spectrophotometer (MTS) method and ion chromatography (IC) method etc, the results have been tabled and the determination methods are confirmed. Then emission characteristics of HC1 during incineration of PVC, PCP and NaCl in a pipe stove with or without water vapor are studied when their temperature is rapidly increased and the results are simulated by math formulas. In addition, pyrolysis and combustion mechanisms of representative plastics are discussed. According to chemical reaction kinetics HC1 emission in combustion of PVC and PCP is studied by thermal gravity analyzer and dynamics parameters are acquired.The effects of particle distribution of fly ash from a MSW incinerator on de novo formation of dioxins with the use of organic/inorganic chorine sources and the relative action of different chlorine sources in de novo formation are studied. Chlorine source for chlorination reaction, various factors of influencing chlorination such as characteristics of fly ash, atmosphere, and the roles of copper, iron, sulfur etc. are discussed. In addition, chlorination in gas and solid phases and special roles of copper and iron in chlorination are also analyzed. In terms of theories of chlorination in solid phase, chlorination mechanisms for inorganic chlorine in de novo reaction are studied and compared with formation mechanisms of dioxins from organic chlorine PVC.In this paper the relation between HC1 and dioxins emission and input of chlorine in a co-firing coal/MSWI CFB incinerator with MSW and coal cofired is studied, removal of sulfur and chlorine is talked over with Ca-base absorbents added directly in furnace, and the removal efficiency of dioxins through a wet scrubber is also investigated.