Abstract:

Fine particulate matter (PM_2.5) in the waste gas emitted from three types of coal-fired heating plants (thermal power, heat source, and power plants) was sampled using the dilution channel sampling method. The main components of PM_2.5, as well as the emission characteristics of SO₂, NO_x, PM_2.5, NH₃, and the chemical component characteristics of PM_2.5, were analyzed based on online monitoring data. The results showed that the average emission concentrations of SO₂, NO_x, PM_2.5 and NH₃ from the three types of coal-fired heating enterprises ranged from 1.01‒15.0, 18.6‒39.8, 0.592‒2.37, 0.125‒2.00 mg·m⁻³, respectively, with a great difference in emission concentrations. Among them, the heat source plant using coal with low sulfur content had a significantly lower SO₂ emission concentration than the thermal power and power plants. In thermal power plants and power plants, the emission concentrations of SO₂, NO_x and PM_2.5 met the requirements of the national ultra-low emission limit, and the heat source plant met the emission standard limit requirements of local coal-fired boilers in Shandong Province. In terms of the component characteristics of PM_2.5, the main components of the different types of heating plants differed significantly, with SO₄²⁻ (11.8%) and OC (17.1%) for thermal power plants, Ca²⁺ (11.6%) and OC (33.5%) for heat source plants, and SO₄²⁻ (23.0%) and OC (18.6%) for power plants, all of which had much higher OC proportions than those of other regions in China. This may be related to the operating conditions of the coal quality and the environmental protection facilities of local enterprises. The high proportions of SO₄²⁻ in thermal and power plants are related to the high sulfur content of the fuel. During the heating season from 2022 to 2023, the total amount of water-soluble ions in PM_2.5, the component of flue gas emitted by the three types of heating enterprises in Ji’nan City, was the largest, and the total annual emission was 3.74×10⁴ kg, which is 2.07 times that of the carbon component and 5.18 times that of the inorganic elements. The total amount of water-soluble ions emitted by power plants was the highest. The annual emission was 3.01×10⁴ kg, accounting for 80.5%. The water-soluble ion emission of the heat source plant is 4.14 times that of the thermal power plant, and the inorganic element emission of the heat source plant was the highest, with an annual emission of 4.96×10³ kg. Water-soluble ions (0.605 kg∙m⁻³ flue gas), carbon components (0.715 kg∙m⁻³ flue gas), and inorganic elements (0.161 kg∙m⁻³ flue gas) in the heat source plant exhibited high emission characteristics. The control of carbon components and water-soluble ions in PM_2.5 from the heat source plant in winter and giving attention to the stable operation of denitration facilities are recommended. This study can provide data support for the decision-making of air PM_2.5 pollution control in Ji’nan, Shandong, China.

Key words: coal-fired heating enterprise, exhaust pollutant, PM_2.5 composition spectrum, component characteristics, emission estimation

摘要：

利用稀释通道采样法于2022年12月对济南市热电厂、热源厂、电厂3种类型冬季燃煤供暖典型企业废气细颗粒物进行采样，结合在线监测数据分析了SO₂、NO_x、PM_2.5和NH₃排放情况及PM_2.5化学组分特征，并估算了济南市冬季3种类型供暖企业PM_2.5主要组分排放量。结果表明：3种类型燃煤供暖企业SO₂、NO_x、PM_2.5和NH₃排放浓度均值范围分别为1.01—15.0、18.6—39.8、0.592—2.37、0.125—2.00 mg∙m⁻³，排放浓度差异较大，其中使用含硫率较低的燃煤供暖热源厂SO₂排放浓度明显低于热电厂和电厂。热电厂和电厂SO₂、NO_x、PM_2.5排放浓度均满足国家超低排放限值要求，热源厂满足山东省地方燃煤锅炉排放标准限值要求。PM_2.5组分特征分析结果表明不同供暖类型企业排放主要组分存在较大差异，其中热电厂主要为SO₄²⁻（11.8%）、OC（17.1%），热源厂主要为Ca²⁺（11.6%）、OC（33.5%），电厂主要为SO₄²⁻（23.0%）、OC（18.6%），3类企业OC占比均远高于国内其他地区，这可能与本地调查企业煤质及环保设施运行工况等有关，热电厂和电厂高的SO₄²⁻占比与燃料含硫率较高有关。经估算，2022—2023年供暖季济南市3种类型供暖企业排放烟气PM_2.5组分中水溶性离子总量最多，排放总量为3.74×10⁴ kg，是碳组分的2.07倍，是无机元素的5.18倍，其中水溶性离子排放总量以电厂最多，排放量为3.01×10⁴ kg，占比为80.5%；热源厂水溶性离子排放量是热电厂的4.14倍，无机元素排放量以电厂最高，排放量为4.96×10³ kg，热源厂的水溶性离子（0.605 kg∙m⁻³烟气）、碳组分（0.715 kg∙m⁻³烟气）、无机元素（0.161 kg∙m⁻³烟气）均呈现高排放特征，建议进一步加强对冬季热源厂PM_2.5中碳组分及水溶性离子的管控，关注脱硝设施的稳定运行。

关键词: 燃煤供暖企业, 废气污染物, PM_2.5成分谱, 组分特征, 排放估算