Dioxins, which are of the most toxic materials on the earth, are principal emitted from waste incineration process. The molecular structures, toxicity parameters, such as toxicity equivalency factor, tolerable daily i...Dioxins, which are of the most toxic materials on the earth, are principal emitted from waste incineration process. The molecular structures, toxicity parameters, such as toxicity equivalency factor, tolerable daily intake and physic-chemical properties of dioxins are briefly summarized. Three formation mechanisms of dioxins in waste incineration process, namely as de novo synthesis, mechanisms involving small organic molecular as precursors and homogenous gas phase reaction mechanism are alto reviewed. The influencing factors for dioxins formation during waste incineration process are also discussed. Three major methods for reducing dioxins emission from waste incineration process are discussed based upon the formation mechanisms and influencing factors. A new waste incineration process with low dioxins emission and low hydrogen chloride corrosion has been proposed based on multi- stage unit operation principal according to formation mechanisms of dioxins and potential production location in waste incinerators.展开更多
With the addition of urea as an inhibitor, four groups of reducing dioxin emission experiments in sintering pot were conducted. The results show that, adding 0.05%, 0.1% and 0.5% （mass fraction） urea, the emission c...With the addition of urea as an inhibitor, four groups of reducing dioxin emission experiments in sintering pot were conducted. The results show that, adding 0.05%, 0.1% and 0.5% （mass fraction） urea, the emission concentrations of dioxin are 0.287 0.258 and 0.217 ng-TEQ/m3, respectively. The dioxin emission rates drop substantially compared to 0.777 ng-TEQ/m3 flee of urea. With an increase of the urea content, the concentration of SO2 emission reduces sharply. （NH4）2SO4, formed by the reaction of SO2 and NH3, goes into the dust and part of NH3 is released before reaction with the emission of exhaust gas. The NO~ emission presents an increasing trend because the reaction of NH3 and 02 at high temperature produces NOx. Based on the consideration of factors such as the effect of reducing dioxin emission, and the chemical composition of exhaust gas, 0.05% is the optimum adding content of urea.展开更多
针对上海这一特大城市,构建了Weather Research and Forecasting-Community Multiscale Air Quality(WRF-CMAQ)耦合模型以分析二噁英(polychlorinated dibenzo-p-dioxins and furans,PCDD/Fs)的大气传输过程和呼吸暴露风险.结果表明:模...针对上海这一特大城市,构建了Weather Research and Forecasting-Community Multiscale Air Quality(WRF-CMAQ)耦合模型以分析二噁英(polychlorinated dibenzo-p-dioxins and furans,PCDD/Fs)的大气传输过程和呼吸暴露风险.结果表明:模型模拟的PCDD/Fs浓度中有69.88%的模拟值为观测值的0.5~2倍,精度良好.2019年上海大气在冬季的PCDD/Fs污染水平最高,其次是在秋季和春季,最低是在夏季,质量浓度分别为847.08、629.53、588.38和406.96 fg/m^(3),毒性当量TEQ浓度分别为59.29、44.46、40.80和28.08 fg I-TEQ/m^(3).大气PCDD/Fs污染严重的地方为杨浦区、虹口区、黄浦区、静安区、宝山区、金山区、松江区.上海居民对PCDD/Fs的呼吸暴露量表现为幼儿>老年人>成年人的趋势,分别为10.67、8.86和8.47 fg I-TEQ/(kg·d),暴露风险均在可接受水平内.此外,本地排放源对污染的贡献远大于外地排放源,这说明上海大气中的PCDD/Fs污染主要是由本地的工业生产过程和燃烧活动造成的.展开更多
文摘Dioxins, which are of the most toxic materials on the earth, are principal emitted from waste incineration process. The molecular structures, toxicity parameters, such as toxicity equivalency factor, tolerable daily intake and physic-chemical properties of dioxins are briefly summarized. Three formation mechanisms of dioxins in waste incineration process, namely as de novo synthesis, mechanisms involving small organic molecular as precursors and homogenous gas phase reaction mechanism are alto reviewed. The influencing factors for dioxins formation during waste incineration process are also discussed. Three major methods for reducing dioxins emission from waste incineration process are discussed based upon the formation mechanisms and influencing factors. A new waste incineration process with low dioxins emission and low hydrogen chloride corrosion has been proposed based on multi- stage unit operation principal according to formation mechanisms of dioxins and potential production location in waste incinerators.
基金Project(50904001) supported by the National Natural Science Foundation of ChinaProject(2010SQRL032D) supported by Anhui Provincial Key Science Foundation for Outstanding Young Talent,ChinaProject(TD200909) supported by Program for Innovative Research Team in Anhui University of Technology,China
文摘With the addition of urea as an inhibitor, four groups of reducing dioxin emission experiments in sintering pot were conducted. The results show that, adding 0.05%, 0.1% and 0.5% （mass fraction） urea, the emission concentrations of dioxin are 0.287 0.258 and 0.217 ng-TEQ/m3, respectively. The dioxin emission rates drop substantially compared to 0.777 ng-TEQ/m3 flee of urea. With an increase of the urea content, the concentration of SO2 emission reduces sharply. （NH4）2SO4, formed by the reaction of SO2 and NH3, goes into the dust and part of NH3 is released before reaction with the emission of exhaust gas. The NO~ emission presents an increasing trend because the reaction of NH3 and 02 at high temperature produces NOx. Based on the consideration of factors such as the effect of reducing dioxin emission, and the chemical composition of exhaust gas, 0.05% is the optimum adding content of urea.
文摘针对上海这一特大城市,构建了Weather Research and Forecasting-Community Multiscale Air Quality(WRF-CMAQ)耦合模型以分析二噁英(polychlorinated dibenzo-p-dioxins and furans,PCDD/Fs)的大气传输过程和呼吸暴露风险.结果表明:模型模拟的PCDD/Fs浓度中有69.88%的模拟值为观测值的0.5~2倍,精度良好.2019年上海大气在冬季的PCDD/Fs污染水平最高,其次是在秋季和春季,最低是在夏季,质量浓度分别为847.08、629.53、588.38和406.96 fg/m^(3),毒性当量TEQ浓度分别为59.29、44.46、40.80和28.08 fg I-TEQ/m^(3).大气PCDD/Fs污染严重的地方为杨浦区、虹口区、黄浦区、静安区、宝山区、金山区、松江区.上海居民对PCDD/Fs的呼吸暴露量表现为幼儿>老年人>成年人的趋势,分别为10.67、8.86和8.47 fg I-TEQ/(kg·d),暴露风险均在可接受水平内.此外,本地排放源对污染的贡献远大于外地排放源,这说明上海大气中的PCDD/Fs污染主要是由本地的工业生产过程和燃烧活动造成的.
