摘要
有效利用生物质能源是实现“碳中和”目标的重要举措,高效控制造粒生物质锅炉燃烧过程中NO x的生成有助于实现烟气达标排放。通过设计带有J型炉拱的新型造粒生物质锅炉炉膛,并在不同一二次风配比下模拟了林木基(杨木)造粒生物质燃烧的NO x浓度分布,进而通过试验研究得出了锅炉燃烧效率和NO x浓度场。结果表明:设置J型炉拱的新型炉膛能更有效地分配一二次风,延长高温烟气在其中的行程,为造粒生物质的分步燃烧提供了有利条件;随着二次风配比的增加,炉膛内高温区从尾部向进料处迁移,且NO x高浓度区域总是出现在高温燃烧区域;一二次风配比为75/25时,锅炉燃烧效率及热效率达到最高,分别为96.30%和80.61%;随着二次风配比增加,锅炉出口处NO x浓度减小,一二次风配比为70/30、75/25时,NO x排放浓度分别为69.54、77.33 mg/Nm 3。综合考虑锅炉燃烧效率和NO x排放浓度,确定一二次风最佳配比为75/25。J型炉拱的设置和一二次风配比的优化极大地提高了锅炉燃烧效率,高效控制了NO x的生成。
Efficient use of biomass energy is an important measure to achieve the goal of“carbon neutrality”,and control of NO x generation during the combustion process in pelletized biomass boilers will promote to achieve flue gas emission standards.In this paper,a new type of biomass boiler furnace with a J-shaped furnace arch was designed,and the NO x concentration distribution during wood-based(poplar)pelletized biomass combustion was simulated under the different primary and secondary air ratios,to explore the boiler combustion efficiency and NO x concentration field.The experimental results exhibited that the new furnace with J-shaped arch could distribute the primary and secondary air more effectively,and extend the stroke of high-temperature flue gas,providing favorable conditions for the stepwise combustion of pelletized biomass.With the increase of the secondary air ratio,the high temperature area in the furnace migrated from the tail to the feed,and the high NO x concentration area always appeared in the high temperature combustion area.When the primary and secondary air ratio was 75/25,the boiler combustion efficiency and thermal efficiency reached the maximum of 96.30%and 80.61%,respectively,while the NO x concentration at the boiler outlet decreased.When the primary and secondary air ratio were 70/30 and 75/25,the NO x emission concentration is 69.54 mg/Nm 3 and 77.33 mg/Nm 3,respectively.Considering the boiler combustion efficiency and NO x emission concentration comprehensively,the optimal ratio of primary and secondary air was determined to be 75/25.In general,the setting of the J-shaped furnace arch and the optimization of the primary and secondary air ratio greatly improved the boiler combustion efficiency and efficiently control the generation of NO x.
作者
朱复东
ZHU Fu-dong(School of Environmental Science and Engineering,Tianjin University,Tianjin 300350,China)
出处
《环境生态学》
2021年第10期63-69,共7页
Environmental Ecology
基金
江苏省首台套重大装备及关键零部件创新基金项目。
关键词
造粒生物质锅炉
J型炉拱
配风
NO
x
控氮燃烧
Granulating biomass boiler
J-shaped furnace arch
air distribution
NO x
nitrogen-controlled combustion
