In order to understand the dioxin migration characteristics during the water-washing pretreatment process and thermal degradation characteristics during the co-processing process in cement kilns,based on the demonstration line of cement kiln co-processing of municipal solid waste incineration (MSWI)fly ash in Liulihe Cement Company in Beijing,an industrial test about MSWI fly ash dechlorination by water-washing pretreatment and washed fly ash feeding into the cement kiln was carried out.The results showed that the dioxin emission concentrations in the flue gases of the fly ash drying machine and cement kiln inlet were lower than the emission limit value (measured as I-TEQ) of O.1 ng/m3 prescribed in " Standard for Pollution Control on Co-Processing of Solid Wastes in Cement Kilns" (GB 30485-2013),and the dioxin concentration in the crystallized chlorine salt(measured as I-TEQ)was only 2.8 ng/kg.Taking the mass of dioxins in the raw fly ash fed into the washing tank in 1 h as 100％,after water-washing pretreatment,99.97％ of dioxin remained in the dechlorinated fly ash,while only 0.081％ and 0.14％ of dioxin was discharged in the fly ash drying machine flue gas and crystallized chlorine salt,respectively.Taking the mass of dioxin in the fly ash fed into the cement kiln in 1 h as 100％,only 0.82％,0.13％ and 0.0021％ of dioxin was discharged in the cement kiln dust,clinker and flue gas,respectively.The dioxin reduction efficiency of fly ash in the cement kiln reached over 99％ which indicated a more complete degradation for the dioxin had been achieved.%为了解生活垃圾焚烧飞灰中的二(噁)英在水泥脱氯预处理过程中的迁移特性以及在水泥窑内的热降解特性,依托北京市琉璃河水泥有限公司的生活垃圾焚烧飞灰水泥窑协同处置示范线,开展了生活垃圾焚烧飞灰的水洗脱氯预处理和水洗后飞灰向水泥窑投加的工程试验研究.结果表明:烘干烟气中和水泥窑窑尾烟气中二(噁)英排放浓度低于GB 30485-2013《水泥窑协同处置固体废物污染控制标准》中所规定的标准限值(以I-TEQ计)为0.1 ng/m3,结晶氯盐中二(噁)英含量(以I-TEQ计)仅为2.8 ng/kg;以每h进入水洗罐的原飞灰中所含二(噁)英量为100％计,经过水洗处理后,99.97％的二(噁)英仍留在脱氯飞灰中,仅有0.08％和0.14％的二(噁)英分别通过烘干废气和结晶盐排出;以每h投入水泥窑窑尾烟室的飞灰所含二(噁)英为100％计,仅有0.82％、0.13％和0.002％的二(噁)英分别随窑灰、熟料、烟气排出,飞灰中的二(噁)英在水泥窑内的消减率达到了99％以上,实现了较为彻底的降解.
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