Abstract:

Waste incineration has the advantages of volume reduction and resource utilization. In recent years, it has gradually replaced landfill and become an important way of solid waste disposal vigorously developed by countries around the world. Waste components are complex and harmful substances are diverse. After incineration, toxic and harmful aromatic hydrocarbon compounds will inevitably be produced, which will harm the atmospheric environment and human health. This paper developed an online monitoring system for aromatic hydrocarbon compounds in waste incineration flue gas based on photoionization time-of-flight mass spectrometry. The online monitoring system was then used to study the online monitoring and dynamic emission characteristics of representative substances such as benzene series, phenolic compounds, polycyclic aromatic hydrocarbons, and chlorinated aromatic hydrocarbons at the inlet and outlet of the selective catalytic reduction (SCR) device in a large-scale waste incineration plant. The study clarified the removal effect of the SCR device on typical aromatic hydrocarbon compounds in waste incineration flue gas. The results showed that the detection limit of the on-line monitoring system can reach ppb level, and the relative deviation (RSD) of the signal intensity of continuous monitoring for 5000 min was only 4.2%. The profile of aromatic hydrocarbon in the flue gases at inlet of SCR equipment was obviously different from that at the outlet, among which xylene and toluene were found to be the major contributors to this distinction. The SCR equipment has a good effect on the removal of aromatic hydrocarbon in flue gas. After flowing through the SCR equipment, the signal intensity of BTEX, phenols, PAHs, chlorobenzene, chlorophenol, chlorotoluene and chlorocresol decreased by 11.3%—91.5%, 47.7%—93.0%, 66.3%—94.9%, 26.4%— 84.5%, 48.5%—88.7%, 53.9%—89.5% and 67.3%—91.0%, respectively.

Key words: waste incineration, PAHs, on-line monitoring, SCR, removal characteristic

摘要：

垃圾焚烧具有减量化和资源化等优点，近年来已逐渐替代垃圾填埋而成为世界各国大力发展的固废处置重要方式。垃圾组分复杂且有害物质多样，经焚烧处理后不可避免地会产生有毒有害的芳香烃化合物，对大气环境和人体健康产生危害。研制了基于光电离飞行时间质谱的垃圾焚烧烟气中芳香烃化合物在线监测系统，并利用在线监测系统对某大型垃圾焚烧厂的选择性催化还原（selective catalytic reduction，SCR）装置出入口烟气中的苯系物、酚类化合物、多环芳烃化合物和氯代芳烃化合物的代表性物质进行在线监测和动态排放特征研究，明确了SCR装置对垃圾焚烧烟气中典型芳香烃化合物的脱除效果。结果表明，研制的在线监测系统对芳香烃化合物的检出限可达ppb级别，且连续监测5000 min信号强度的相对偏差（RSD）仅为4.2%；SCR装置入口和出口烟气中芳烃化合物的分布模式显著不同，二甲苯和甲苯对差异的贡献最大；SCR装置对烟气中的芳香烃化合物均具有较好的脱除效果，烟气流经SCR装置后，苯系物、酚类、多环芳烃类、氯苯类、氯酚类、氯甲苯类和氯甲酚类化合物的信号强度分别下降11.3%~91.5%、47.7%~93.0%、66.3%~94.9%、26.4%~84.5%、48.5%~88.7%、53.9%~89.5%和67.3%~91.0%。

关键词: 垃圾焚烧, 芳香烃化合物, 在线监测, 选择性催化还原装置, 脱除特性