生物质锅炉与燃煤锅炉颗粒物排放特征比较

选择2台设计结构不同的生物质锅炉(BB1、BB2),针对木质和秸秆2种生物质燃料开展烟尘、PM₁₀和PM_2.5排放特征的研究,并与燃煤锅炉进行比较. 结果表明:2台生物质锅炉的大气污染物排放质量浓度都未达到北京市DB 11/139—2007《锅炉大气污染物排放标准》的要求；2台生物质锅炉颗粒物的排放因子存在差别,燃烧木质成型燃料时,BB1和BB2生物质锅炉除尘器后的烟尘排放因子分别为207.10和465.51mg/kg,PM₁₀排放因子分别为75.18和149.61mg/kg, PM_2.5排放因子分别为58.48和106.86mg/kg；燃烧秸秆成型燃料时,BB1和BB2生物质锅炉除尘器后的烟尘排放因子分别为142.86和1200.86mg/kg,PM₁₀排放因子分别为63.63和102.01mg/kg,PM_2.5的排放因子分别为50.90和76.51mg/kg. 与热功率相近的燃煤锅炉比较,2台生物质锅炉除尘器前的PM₁₀平均排放因子低30.41%,PM_2.5平均排放因子却高36.84%,即PM_2.5在生物质锅炉烟尘中所占比例更高. 尽管利用可再生能源的生物质锅炉具有很好的发展前景,但目前该类锅炉仍存在污染物排放不达标的现象,因此,需要提高热能利用效率和除尘效率,以减少污染. 

Comparative Study on the Particle Emission Characteristics of Biomass Boiler with Coal-Fired Industrial Boiler

Biomass boilers were widely used as an effective method for biomass combustion. However, there were not many studies on the characteristics of atmospheric pollutants emitted from biomass boilers. Two biomass boilers with different structure were selected to study the emission characteristics of dust, PM₁₀ and PM_2.5 and compare it with coal-fired boiler. Wooden block fuel (MZ) and straw block fuel (JG) were used in this study. The results showed that the emission concentrations of pollutants from both biomass boilers could not fulfill Beijing local standard “Emission standard of air pollutants for boilers” (DB 11/139-2007). The emission factors using two types of biomass boilers showed a significant difference. For the wooden block fuel, the dust emission factors were 207.10mg/kg (BB1) and 465.51mg/kg (BB2); the PM₁₀ emission factors were 75.18mg/kg (BB1) and 149.61mg/kg (BB2); the PM_2.5 emission factors were 58.48mg/kg (BB1) and 106.86mg/kg (BB2) respectively. For the straw block fuel, the dust emission factors were 142.86mg/kg (BB1) and 1200.86mg/kg (BB2), the PM₁₀ emission factors were 63.63mg/kg(BB1) and 102.01mg/kg(BB2); the PM_2.5 emission factors were 50.90mg/kg(BB1) and 76.51mg/kg(BB2) respectively. Compared with the coal-fired boiler under the similar condition of thermal power, the average PM₁₀ emission factor of two biomass boilers was 30.41% lower than that for the coal-fired boiler, while the average PM_2.5 emission factor of two biomass boilers was 36.84% higher than that for the coal-fired boiler. PM_2.5 in the dust of biomass boiler has a higher proportion than that for the coal-fired boiler. Although biomass boiler has a very good applicable perspective due to its recycling applicability, the emission of atmospheric pollutants from some biomass boilers could not meet the local standard. Consequently, the current energy efficiency and dust removal efficiency should be improved to reduce the pollution to atmospheric environment.