西安城区燃煤锅炉颗粒物排放特征研究

EMISSION CHARACTERISTICS OF PARTICULATE MATTER FROM COAL-FIRED BOILERS IN XI’AN CITY

针对西安市雾霾频发,在集中供热期利用冷凝法收集了5台燃煤锅炉排放的湿烟气中的冷凝液,分析了湿烟气中颗粒物的排放特征。实验结果表明:5台锅炉排放的烟气中可溶性盐的浓度为0. 92～10. 59 mg/m3,不溶性颗粒物浓度为0. 46～6. 31 mg/m3,供热燃煤锅炉的可溶性盐和不溶性颗粒物的排放量明显高于电厂燃煤锅炉。水溶性盐中主要成分含有SO2-4、NH+4、Cl-以及Ca2+,其中SO2-4含量最高,质量分数为55. 69%～66. 84%。根据现场测试结果和西安城区燃煤锅炉的燃煤量推算:当静风天气持续48 h时,分别以300,500 m的空间高度为基准,计算得出燃煤锅炉排放的可溶性盐对西安城区大气中颗粒物浓度的贡献量分别为6. 6,3. 96μg/m3。

For the spate of haze in Xi＇ an, by the condensation method, condensed fluid was collected from wet flue gas emitted by 5 boilers during the central heating period. And emission characteristics of particulate matter were analysed. Results demonstrated that the concentration of soluble salt and insoluble particulate matter in the flue gas were in the range of 0. 92 ~ 10.59 mg/m3 and 0.46 ~ 6. 31 mg/m3 ,respectively, whose concentration levels were higher in heating coal boiler than in power plant boiler. Components of soluble salt mainly involved S024- , NH4 , C1- and Ca2~ . S024- was the most abundant component among soluble salt, with the mass fraction of 55.69% -66. 84%. According to field measurement results and coal consumptions of coal-fired boilers in Xi＇an City, it was estimated that in calm wind weather, soluble salt from coal-fired boilers contributed 6.6 μg/m3 and 4. 0 μg/m3 to the concentrations of particulate matter in the atmosphere,respectively based on spatial height of 300 m and 500 m within 48 hours.