大型炉排炉清洁高效燃烧的问题剖析与实炉优化  

Analysis and Optimization for Practical Applications of Clean and Efficient Combustion of Large-scale Grate Furnace

作　　者：张睿智[1] 汪林正 赵善辉 邓睿渠 罗永浩[1] ZHANG Ruizhi;WANG Linzheng;ZHAO Shanhui;DENG Ruiqu;LUO Yonghao(School of Mechanical Engineering,Shanghai JiaoTong University,Shanghai 200240,China;Department of Mechanical Engineering,Massachusetts Institute of Technology,Cambridge M A 02139,USA;School of Energy and Power Engineering,Nanjing Institute of Technology,Nanjing 211167,China)

机构地区：[1]上海交通大学机械与动力工程学院,上海200240 [2]麻省理工学院机械工程系,马萨诸塞州剑桥市02139 [3]南京工程学院能源与动力工程学院,南京211167

出　　处：《动力工程学报》2024年第5期681-691,共11页Journal of Chinese Society of Power Engineering

摘　　要：大型炉排炉被广泛应用于生物质及生活垃圾的能源化转化,但由于其设计和运行仍处于工程经验探索阶段,实际运行过程中,存在过量空气系数大、气固相燃尽差、NO_(x)原始排放高等问题。针对炉排炉复杂的层燃反应过程,构建了大颗粒转化模型和多成分并行颗粒层燃模型,实现对炉排炉燃烧过程的精细化数值模拟。并通过与实验结果进行对比,验证模型的精度。利用数值模拟方法,分别针对生活垃圾和农业秸秆的大型炉排炉进行了实炉分析与优化,并根据表面着火和底部着火2种层燃模式,进行了现场运行调整。结果表明:某中拱型垃圾焚烧炉的炉膛局部高温和NO_(x)排放较高的问题,源自于前后侧烟道的组分分布、燃烧和还原反应与设计预期的偏离,运行优化后消除了实炉的局部高温,NO_(x)排放亦显著下降,所提出的结构改进方案可使NO_(x)原始排放降低至26.8 mg/m^(3);某秸秆振动炉排发电锅炉的床层和气相燃烧效率低的问题,源自于大一次风的对流冷却作用和炉膛内的“烟囱流”现象,运行优化后实炉CO排放大幅减少,发电负荷显著上升。Large-scale grate furnaces have been widely used in the energy conversion of biomass and municipal solid wastes(MSW).However,due to the fact that design and operation of grate furnaces are still in the stage of engineering exploration,in the actual operation process,there are still problems such as high excessive air rate,poor combustion efficiency in both gas and solid phase,and high initial NO_(x) emissions.In response to the complex layered combustion process of grate furnaces,a large-particle conversion model and a multi-component parallel particle combustion model were constructed to achieve fine numerical simulation of actual grate furnace combustion processes.The accuracy of this model was verified by comparing with experimental results.Using numerical simulation methods,real-furnace analysis and optimization were carried out for large-scale grate furnaces burning MSW and agricultural straw.Based on the surface-and bottom-ignition modes,on-site adjustments were made.Results show that for the middle-arch SW incinerator,localized high temperature and high NO_(x) emission are mainly caused by the departure of component distribution,combustion and reduction reactions from design,which are clearly improved by the operation adjustment.According to numerical modeling calculation,a further optimization in its structure can reduce NO_(x) emission to 26.8 mg/m^(3).For the vibrating grate boiler for straw,low combustion efficiency in gas and solid phase is mainly caused by the convective cooling of large primary air and the"chimney-like flow"in furnace.After optimization,its emission is hugely reduced,and power-generation load remarkably rises.

关 键 词：生物质 大型炉排炉 清洁燃烧 NOx 数值模拟 

分 类 号：TK229[动力工程及工程热物理—动力机械及工程]