长三角地区中小燃煤锅炉PM_(2.5)成分谱特征

Chemical Composition Characteristics of PM_(2.5) Emitted by Medium and Small Capacity Coal-fired Boilers in the Yangtze River Delta Region

选取7台中小燃煤锅炉,分析其排放的烟气中PM_(2.5)的排放因子、成分谱特征和除尘设施对不同粒径段的PM_(2.5)、OC、EC的去除效率.研究发现:除尘设施出口处的PM_(2.5)质量排放因子在0.047~0.283 g·kg^(-1)之间,平均为(0.146±0.081)g·kg^(-1).SO_4^(2-)在离子组分中的含量最为丰富,其次为NH_4^+和Ca^(2+);S在元素组分中的含量最为丰富,其次为Al、Ca、Fe;OC、EC的含量波动幅度较大,各锅炉产生的OC和EC比值均大于1.在所测粒径的范围内,PM_(2.5)的质量浓度呈单峰或双峰分布,峰值点出现在0.07~0.12μm处和1μm以上(双峰时);OC的粒径分布呈双峰或三峰的特征,峰值点分别出现在0.04μm和0.20~0.31μm处和1μm以上(三峰时).除尘设施对PM_(2.5)、OC、EC质量浓度的整体去除效率分别为66%、53%和23%.

Seven small and medium coal-fired boilers were selected to analyze the emission factors and chemical composition characteristics of PM2.5,and the efficiency of the dust collection unit in removing PM2.5,OC,and EC of different particle sizes. At the outlet of the dust collection unit,PM2.5 mass emission factor was around 0. 047-0. 283 g·kg^-1 with an average of（ 0. 146 ± 0. 081）g·kg^-1. SO4^2- was the most abundant ionic component,followed by NH4^＋ and Ca^2＋. S was the most abundant among all the elements,followed by Al,Ca,and Fe. The contents of OC and EC fluctuated greatly,and the ratio of OC and EC produced by each boiler was greater than one. In the range of the measured particle sizes,the mass concentration of PM2.5 showed a singlet or bimodal distribution,and the peak value appeared at 0. 07-0. 12 μm and greater than 1 μm in bimodal distribution. The mass concentration of OC showed a bimodal or trimodal distribution,and the peak value appeared at 0. 04 μm,0. 20-0. 31 μm,and greater than 1 μm in trimodal distribution. The efficiencies of the dust collection unit in removing PM2.5,OC,and EC were 66%,53%,and 23%,respectively.