摘要:
通过室内模拟燃烧5种生物质,分别采集燃烧排放的烟气作为样品,然后分析生物质和燃烧产物的二噁英含量,得到玉米秸秆、稻草、松树、桉树、松针燃烧的二噁英排放因子分别为2.59、16.78、1.44、5.15、34.12 ng·kg-1,对应的I-TEQ浓度为0.26、1.04、0.10 、0.31、1.49 ng·kg-1.OCDD对浓度贡献最大,所占百分比值分别为28.20%、21.82%、44.73%、64.09%、52.28%;对总毒性当量浓度贡献最大的为2,3,4,7,8-PeCDF,所占百分比值分别为44.62%、37.50%、44.00%、51.61%、40.94%.5种生物质二噁英含量分别为5.01、21.28、3.55、9.10、81.32 ng·kg-1,比对应生物质燃烧的二噁英排放因子大; I-TEQ含量分别为0.014、0.62、0.013、0.13、1.29 ng·kg-1,比对应生物质燃烧的二噁英总毒性当量小.生物质燃烧排放的二噁英一方面来源于原材料释放,尤其是OCDD;另一方面来源于二噁英合成,尤其是低氯代二噁英(P4—5CDD/Fs).2,3,4,7,8-PeCDF与二噁英总浓度及总毒性当量浓度具有较好线性相关性,R2>0.91、P<0.011.
关键词:
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生物质
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燃烧
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二噁英
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排放特性
Abstract:
In this paper, open fire buring of five kinds of biomass were simulated indoor. Their smokes were collected as samples, and the level of dioxins in biomass and combustion products was analyzed. The emission factors of corn stalks, straw, pine, eucalyptus, pine needle are 2.59, 16.78, 1.44, 5.15, 34.12 ng·kg-1, their corresponding I-TEQ concentration are 0.26, 1.04, 0.10, 0.31, 1.49 ng·kg-1. The largest contribution to the concentration is OCDD, the percentage is 28.20%, 21.82%, 44.73%, 64.09%, 52.28%; the largest contribution to the total toxic equivalent concentration is 2,3,4,7,8-PeCDF, the percentage is 44.62%, 37.50%, 44.00%, 51.61%, 40.94%. The contents of dioxins in the five biomass are 5.01,21.28,3.55,9.10,81.32 ng·kg-1, which are large when compared with the emission factor of dioxins in biomass burning. I-TEQ contents are 0.014,0.62,0.013,0.13,1.29 ng·kg-1, which are small when compared with the emission factor of dioxins total toxic equivalent in biomass burning. The dioxins in biomass burning came from the raw materials, particular OCDD, as well as from the formation, especially the low-chlorinated dioxins (P4-5CDD/Fs). The 2,3,4,7,8-PeCDF has a good linear relationship with the total concentration or the total toxic equivalent concentration,with R2>0.91, P<0.011.