高浓度煤粉预燃式强稳燃低氮燃烧器配风组织优化  

Optimization of air distribution of high concentration pulverized coal pre-combustion strong stable combustion low nitrogen burner

作　　者：周旭 张瀚霖 张锋[1,3] 谭厚章 郑海国[1] 刘一[2] 林山虎 王学斌 ZHOU Xu;ZHANG Hanlin;ZHANG Feng;TAN Houzhang;ZHENG Haiguo;LIU Yi;LIN Shanhu;WANG Xuebin(MOE Key Laboratory of Thermo-Fluid Science and Engineering,Xi′an Jiaotong University,Xi′an 710049,China;Key Laboratory for Clean Combustion and Flue Gas Purification of Sichuan Province,Chengdu 611731,China;Shandong Shunye pressure vessel Co.,Ltd,Jinan 250300,China)

机构地区：[1]西安交通大学热流科学与工程教育部重点实验室,陕西西安710049 [2]清洁燃烧与烟气净化四川省重点实验室,四川成都611731 [3]山东舜业压力容器有限公司,山东济南250300

出　　处：《洁净煤技术》2024年第9期43-51,共9页Clean Coal Technology

基　　金：国家重点研发计划青年科学家资助项目(2022YFB4100500)。

摘　　要：煤粉预燃低氮燃烧技术可兼顾稳定燃烧与NO_(x)排放控制,在燃煤锅炉灵活性调峰稳燃领域的应用潜力巨大。依托5 MW燃烧试验平台,研究一种带小型预燃室的高浓度煤粉预燃低氮燃烧器运行性能。通过CFD数值模拟,系统研究了一次风率、内外二次风配风与分离式燃尽风(SOFA)对燃烧器燃烧性能及污染物排放特性的影响。结合5 MW燃烧试验平台测试结果对燃烧模型进行验证验证,试验实际温度与数值计算结果的最大偏差为44℃,误差范围±3.3%,证明所选燃烧模型的准确性。研究结果表明:一次风率是影响预燃室环形回流区的关键因素,过低或过高的一次风速会分别对稳燃能力与降氮能力产生影响,在约8.8%的一次风率条件下能够保证有充足的回流量,有利于煤粉着火和排放控制;升高内二次风率能卷吸更多炉膛内高温烟气,有利于煤粉燃尽,但炉膛内部高温氧化性气氛区域增加,会导致污染物排放有所升高,约为43.5%的内二次风率能兼顾稳燃与降氮效果;采取适当比率的SOFA替代外二次风,能使得燃烧区域的含氮化合物更易被还原,从而降低排放,在23%SOFA风率下出现明显的低氮效果,NO_(x)排放为72 mg/m^(3)(6%O_(2)),与0%SOFA风率相比减排约67%。The low nitrogen combustion technology of pulverized coal pre-combustion can balance stable combustion and NO_(x)emission control,which has great application potential in the field of flexible peak shaving and stable combustion of coal-fired boilers.Based on the 5 MW combustion test rig,the operation performance of a high-concentration pulverized coal pre-combustion low-nitrogen burner with a small pre-combustion chamber developed by the authors′team was studied.The effects of primary air rate,internal and external secondary air distribution and separate over-fire air(SOFA)on the combustion performance and pollutant emission of the burner were systematically studied by CFD numerical simulation.The combustion model was verified by the test results of the 5 MW combustion test rig.The maximum deviation between the actual temperature and the numerical calculation results is 44℃,and the error range is±3.3%,which proves the accuracy of the selected combustion model.The results show that the primary air rate is the key factor affecting the backflow zone of the pre-combustion chamber,and too low or too high primary air rate will affect the combustion stability and nitrogen reduction ability respectively.Under the condition of 8.8%primary air rate,sufficient backflow can be guaranteed,which is conducive to the ignition and emission control of pulverized coal.Increasing the internal secondary air rate can entrain more high-temperature flue gas in the furnace,which is conducive to the burning of pulverized coal.However,the increase of the high-temperature oxidizing atmosphere area in the furnace will lead to the increase of pollutant emission.The internal secondary air rate of about 43.5%can both stabilize combustion and reduce nitrogen.Replacing the external secondary air with an appropriate proportion of SOFA can make the nitrogen-containing compounds in the combustion area more easily reduced,thus reducing emissions.At 23%SOFA rate,a significant nitrogen reduction effect was observed,with NO_(x)emissions of 72 mg/m^

关 键 词：预燃低氮燃烧 燃烧器 配风优化 数值模拟 NO_(x)排放 

分 类 号：TK16[动力工程及工程热物理—热能工程]