300MW四角切圆锅炉低负荷下燃烧特性数值模拟研究  

Numerical simulation on combustion characteristics of a 300 MW tangentially-fired boiler under low load

作　　者：江志铭 张妍 李越胜 邱燕飞 宋长志 刘虎 邓磊[3] 车得福[3] JIANG Zhiming;ZHANG Yan;LI Yuesheng;QIU Yanfei;SONG Changzhi;LIU Hu;DENG Lei;CHE Defu(Shunde Institute of Inspection,Guangdong Institute of Special Equipment Inspection and Research,Foshan 528300,China;Quality Supervision and Inspection Center of National Industrial Boiler,Foshan 528300,China;School of Energy and Power Engineering,Xi'an Jiaotong University,Xi′an 710049,China)

机构地区：[1]广东省特种设备检测研究院顺德检测院,广东佛山528300 [2]国家工业锅炉质量监督检验中心,广东佛山528300 [3]西安交通大学能源与动力工程学院,陕西西安710049

出　　处：《洁净煤技术》2021年第3期182-188,共7页Clean Coal Technology

基　　金：广东省质量技术监督局科技项目(2018CT17);国家重点研发计划资助项目(2017YFB0602102)。

摘　　要：随着环保标准提高,电站锅炉NOx排放量控制日益严格。低氮改造可以有效降低NOx生成,而对于改造后低负荷下炉内燃烧特性研究有限。对某电厂低氮改造后的一台300 MW四角切圆煤粉锅炉进行了低负荷下多工况燃烧特性的数值模拟,研究了过量空气系数、燃尽风量和一次风喷口给煤量对炉内速度场、温度场、组分浓度场的影响。通过改进网格系统,提高模拟结果的准确性。数值模拟结果和试验测量值偏差较小,说明其数值模拟结果可信。结果表明:随着过量空气系数的增加,炉内燃烧温度升高,还原性物质减少,NOx排放量增加,当过量空气系数从1.20增加到1.30时,NOx排放从221.12 mg/m^(3)增加到196.26 mg/m^(3);随着燃尽风量增加,主燃区温度降低,燃尽区温度升高,主燃区温度的降低抑制了热力型NOx的生成,NOx排放量降低,当燃尽风量从20%增加到30%时,NOx从231.21 mg/m^(3)降低到180.95 mg/m^(3);一次风喷口给煤量变化对炉膛内温度场、组分浓度场和NOx生成影响较小。With the improvement of environmental protection standards,NOx emission control of power plant boilers is increasingly strict.Low-NOx retrofit can effectively reduce NOx generation,but the research on combustion characteristics in low load after retrofit is limited.The combustion characteristics of a 300 MW low-NOx retrofitted tangentially-fired boiler under low load and multiple operating conditions were numerically simulated in this work.The influence of excess air ratio,burnout air ratio and pulverized coal feeding rate of primary air nozzle on the velocity,temperature and species distributions in the furnace were studied.By improving the grid system,the accuracy of simulation results is improved.The deviation between the simulation results and the experimental measurements is small,which shows that the simulation results are reliable.The results show that with the increase of excess air ratio,the temperature rises up,the reducing species decrease and the NOx emission increases.When the excess air coefficient increases from 1.20 to 1.30,the NOx emission increases from 221.12 mg/m^(3) to 196.26 mg/m^(3).With the increase of burnout air ratio,the temperature of the main combustion zone decreases,the temperature of the burnout zone increases.The reduction of the temperature of the main combustion zone inhibits the generation of thermal NOx,and the NOx emission decreases.When the burnout air ratio increases from 20%to 30%,the NOx emission decreases from 231.21 mg/m^(3) to 180.95 mg/m^(3).The influences of pulverized coal feeding rate for primary air nozzle on temperature,species concentration and NOx emission are small.

关 键 词：四角切圆锅炉 低氮改造 NOx 燃烧特性 数值模拟 

分 类 号：TK16[动力工程及工程热物理—热能工程]