焚烧烟气和大气中二噁英类气-固分布比较研究

Comparison and research on characteristics of PCDD/Fs gas-particle partition in stack gas and atmosphere

探讨生活垃圾焚烧烟气和周边大气中二噁英类的气-固浓度分布特性。通过采样实测某生活垃圾焚烧厂焚烧烟气和周边大气中二噁英类浓度，比较分析生活垃圾焚烧烟气和周边大气气-固浓度分布特性。焚烧烟气中不同氯取代的二噁英类气-固相分布较均衡，气相二噁英类占主导，质量浓度比例为82％～93％；大气中不同氯取代的二噁英类气-固分布很不均匀，固相二噁英类质量浓度比例为85％。烟气从出口到大气环境二噁英类气-固分配存在动态平衡。影响其动态平衡的2个重要影响参数为：气-固分布系数和颗粒态二噁英粒径分布特征。

This paper studies the feature of the PCDD/Fs gas-particle partition in the stack gas and in the ambient atmosphere through measuring some samples.The measurement and modeling results illustrate that the balance of the PCDD/Fs gas-particle partition in the stack gas varies compared with that in the ambient atmosphere.In the stack gas,there is 80% gaseous PCDD/Fs and 20% particulate PCDD/Fs,while the ambient air is consist of 15% gaseous and 85% particulate.Although there is a big difference between the stack gas and the ambient air gas-particle partition,beyond 80% particulate PCDD/Fs primarily are adsorbed on D ae ≤2.5 μm particles,especially on D ae =0.2~0.5 μm particles. The two vital parameters influencing the above partition dynamic balance from the stack gas to the ambient air are the gas-particle distribution coefficient and the particulate PCDD/Fs distribution profile.What is more important,the PCDD/Fs gas-particle partition has a negative correlation with temperature,and a positive correlation with the total suspended particle concentration. The particulate PCDD/Fs distribution profile has some correlation with PM2.5 percentage in the atmosphere.