Abstract:

Condensable particulate matter (CPM) is vapor phase at stack conditions, but forms fine particle matter with diameter less than 2.5μm upon release into the ambient air. Researchers have paid more attention to filterable particulate matter (FPM) than CPM from stationary sources for a long time. Many countries didn’t determining CPM, which caused the underestimation of particle matter emission level and the imperfection of inventory. The existing researches indicate that the emission concentration of CPM from most stationary sources are not lower than FPM, whose effect for the ecological environment cannot be ignored. Nevertheless, at present the cognition of CPM is not enough. In this case, on the basis of limited research reports, formation mechanism, test method, emission level, characterization and control technologies of CPM are reviewed. CPM is mainly generated by vapor components through “heterogeneous condensation” and “homogeneous nucleation”. Impinger cooling method and dilution cooling method are the main determining methods of CPM. Researchers revealed that CPM emission is affected by sulfur content, exhaust gas temperature, pollutant control facilities and operating conditions, in which exhaust gas temperature is the most important influence factor. The physical form of granular CPM is spherical and with a porous surface. The emission CPM from most stationary sources mainly consists of inorganic components, whose major metal element are K, Na, Ca and major soluble ions are SO₄ ^2-、NO₃ ^-、Cl^-、NH₄ ⁺. Conventional particle control facilities have poorer removal efficiency for CPM than FPM. Nowadays, the research of CPM is severe inadequate. The future research of CPM may focus on the aspects like improvement of test method, the CPM characteristics from different stationary sources and the control of CPM.

Key words: condensable particulate matter (CPM), formation mechanism, emission level, test method, composition, control technology

摘要：

可凝结颗粒物（CPM）在烟道环境下为气相，释放到大气环境中快速形成粒径<2.5μm的细颗粒物。长期以来，研究者对CPM的关注较少，固定污染源颗粒物的研究主要针对可过滤颗粒物（FPM）。许多国家未对CPM进行测试，导致了颗粒物排放水平的低估和排放清单的不完整。已有研究表明，大多固定污染源CPM的排放浓度不低于FPM，其对生态环境的影响不容忽视。但目前，人们对CPM的认知依然较少。针对此情况，在有限文献的基础上，本文从CPM的形成机理、测试方法、排放水平、理化特性和控制技术等方面对CPM研究现状进行了综述。CPM主要形成于“异相冷凝”和“均相成核”两种机理，测试方法主要有“冲击冷凝法”和“稀释冷凝法”。研究表明，CPM的排放受燃料含硫量、排烟温度、污染物控制设施及运行工况等影响，其中排烟温度影响最大。颗粒态CPM的形态为球形多孔表面结构。大多固定污染源排放的CPM主要成分为无机组分，其中主要金属元素为K、Na、Ca，主要水溶性离子为SO₄ ^2-、NO₃ ^-、Cl^-、NH₄ ⁺。CPM在常规颗粒物控制设施中的脱除效果差于FPM。目前，CPM的研究尚比较薄弱，未来CPM研究的重点应在测试方法的改进、不同固定污染源排放CPM的特性及CPM的控制等方面。

关键词: 可凝结颗粒物, 形成机理, 排放水平, 测试方法, 化学组分, 控制技术