典型超低排放燃煤电厂可凝结颗粒物特征和成因  

Characteristics of Condensable Particulate Matter in Ultra-low Emission Coal-Fired Power Plants

作　　者：邓建国[1] 王刚 张莹 李妍菁 段雷[1,2] 蒋靖坤 DENG Jian-guo;WANG Gang;ZHANG Ying;LI Yan-jing;DUAN Lei;JIANG Jing-kun(School of Environment,Tsinghua University,Beijing 100084,China;State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex,Beijing 100084,China)

机构地区：[1]清华大学环境学院,北京100084 [2]国家环境保护大气复合污染来源与控制重点实验室,北京100084

出　　处：《环境科学》2020年第4期1589-1593,共5页Environmental Science

基　　金：国家重点研发计划项目(2018YFC0213202)。

摘　　要：燃煤电厂排放的可凝结颗粒物(condensable particle matter,CPM)由于其潜在的大气环境影响引起广泛关注,而目前对于燃煤电厂CPM的特征和成因尚不清楚.本研究通过稀释间接法收集了超低排放改造后的典型燃煤电厂石灰石-石膏湿法脱硫(wet flue gas desulfurization,WFGD)入口/出口和湿式静电除尘(wet electrostatic precipitator,WESP)出口位置的CPM,并对其进行重量分析和水溶性离子分析,同时测量了可能的CPM气态前体物浓度.结果表明,烟气中CPM的主要气态前体物为HCl、HNO3、SO3和NH3等.烟气温度降低后,这些气态前体物通过冷凝或化学反应形成CPM.所形成CPM主要化学组分包括SO4^2-、Cl-、NO-3和NH+4等水溶性离子.WFGD和WESP可以降低CPM气态前体物的浓度,进而减少CPM排放,经过WFGD和WESP后CPM浓度的平均下降比例分别为27%和45%.此外,稀释降温后烟气中的SO3非均相冷凝在已有的颗粒物表面上,导致颗粒物中的SO4^2-增加,同时Cl-和NO-3减少,致使最终排口处CPM的水溶性离子组分主要为SO4^2-.The condensable particle matter(CPM)from coal-fired power plants has attracted significant attention for its potential influence on air quality.The knowledge of CPM emissions from coal-fired power plants is limited.In this study,CPM was collected at the inlet and outlet of wet flue gas desulfurization(WFGD)and the outlet of wet electrostatic precipitator(WESP)using in-direct dilution method.Both mass concentration and water-soluble ions of CPM were analyzed after sampling.The gas precursors were measured at the same time.We showed that gas precursors such as HCl,HNO3,SO3,and NH3 significantly contributed to CPM from coal-fired power plants.As the temperature of flue gas decreased,these gas precursors were observed to form CPM.The major components of CPM were water-soluble ions such as SO4^2-,Cl-,NO-3,and NH+4.WFGD and WESP could reduce the CPM gas precursors.Therefore,CPM concentrations after WFGD and WESP of the five tested coal-fired power plants were reduced by 27%and 45%,respectively.In addition,the condensation of SO3 increased SO4^2-concentration but reduced Cl-and NO-3 contents.Finally,SO4^2-was found to be the major water-soluble ion of CPM.

关 键 词：燃煤电厂 可凝结颗粒物(CPM) 稀释间接法 石灰石-石膏湿法脱硫(WFGD) 湿式电除尘器(WESP) 

分 类 号：X513[环境科学与工程—环境工程]