广东某造纸厂掺烧固体废物的燃煤锅炉烟气中二噁英异构体组分特征

The Characteristics of Dioxins Isomers in Flue Gas of Coal-Fired Boilers Mixed With Solid Waste A case Study in a Paper Mill in Guangdong

为了解掺烧固体废物(主要是造纸备料车间产生的树皮、木屑及污水站污泥)的循环流化床型燃煤锅炉废气二噁英排放水平及其异构体组分特征,选取湛江市某制浆造纸厂的2台锅炉,于2014年2月17~20日对其废气处理设施出口断面进行废气二噁英排放浓度监测。样品二噁英浓度和异构体组分特征由高分辨气相色谱/高分辨质谱联用仪(HRGC-HRMS)分析获得。结果表明,掺烧固体废物的循环流化床型燃煤锅炉烟气中二噁英主要由高氯代PCDD/Fs组成,质量浓度最高分别为OCDD(19.1%)和1,2,3,4,6,7,8-HpCDF(16.6%);当量毒性浓度贡献最大的分别是2,3,4,7,8-PeCDF(40.4%)和2,3,4,6,7,8-HxCDF(13.4%),其单体浓度对二噁英毒性当量浓度大小具有举足轻重的影响,其中2,3,4,6,7,8-HxCDF与当量毒性浓度相关性最强,相关系数R2为0.9525,可作为该类型锅炉烟气中二噁英I-TEQ的指纹特征单体。

In order to understand the dioxin emission level and its isomer composition characteristics of the exhaust gas from the circulating fluidized bed type coal-fired boilers mixed with solid waste which mainly includes bark,wood chips and sewage sludge generated in the paper preparation workshop,two boilers from a pulp and paper mill in Zhanjiang City were selected,and the dioxin emission concentration in the exhaust gas on the export section of exhaust gas treatment facility were monitored,and the monitoring date was from 17th Feb 2014 to 20ed Feb 2014.High resolution gas chromatography/high resolution mass spectrometer (HRGC-HRMS) was used to analyze the dioxin concentration and isomer composition characteristics of the sample.The results show that the dioxin in the flue gas of the circulating fluidized bed type coal-fired boiler with solid waste is mainly composed of high chlorinated PCDD/Fs,in which the highest concentration of OCDD and 1,2,3,4,6,7,8-HpCDF were 19.1 % and 16.6 % respectively.The highest contribution of equivalent toxicity concentration is the composition of 2,3,4,7,8-PeCDF and 2,3,4,6,7,8-HxCDF,which are 13.4 % and 40.4 % respectively,and their monomer concentration has a significant effect on the concentration of dioxin toxicity equivalents,in which the 2,3,4,6,7,8-HxCDF has the strongest correlation with the equivalent toxicity concentration,and the correlation coefficient R2 is 0.9525, which can be used as a fingerprint characteristic monomer of dioxins I-TEQ in this type of boiler flue gas.