超超临界机组锅炉贴壁风系统的数值模拟及工程验证  

Numerical Simulation and Practical Verification of Near-wall Air System for an Ultra-supercritical Boiler

作　　者：陈勤根 林闽城 项群扬 张光学[3] CHEN Qin-gen;LIN Min-cheng;XIANG Qun-yang;ZHANG Guang-xue(Zhejiang Zheneng Techndogy Research Institute Co.,Ltd.,Hangzhou,China,311121;Ningxia Zaoquan Power Generation Co.,Ltd.,Yinchuan,China,750000;Institute of Energy Engineering,China Jiliang University,Hangzhou,China,310018)

机构地区：[1]浙江浙能技术研究院有限公司,浙江杭州311121 [2]宁夏枣泉发电有限责任公司,宁夏银川750000 [3]中国计量大学能源工程研究所,浙江杭州310018

出　　处：《热能动力工程》2022年第10期112-121,共10页Journal of Engineering for Thermal Energy and Power

基　　金：浙能集团科技项目资助(ZNKJ-2019-053);浙江省属高校基本科研业务费专项资金(2020YW04)。

摘　　要：为了解决某660 MW超超临界对冲燃烧锅炉的高温腐蚀问题,提出了前后墙布置高速直流贴壁风改造方案,并采用计算流体力学理论对该方案进行数值模拟。改造前的锅炉温度沿高度分布、主燃区水冷壁贴壁气氛等模拟数据与实测结果基本符合,验证了模拟的准确性。结果表明:当贴壁风率较低时,由于炉膛内温度高、烟气粘度大,射流穿透力不足,效果较差;当贴壁风率达到3%以上时,射流动量和初始速度增大,射流刚性增强,能够抵达高温腐蚀区域;贴壁风对炉膛中间主体区域的气体组分影响不大,仅提高了侧墙贴壁区域的氧化性气氛,使具有高温腐蚀倾向的水冷壁面积大幅减少。实际改造结果表明,该方案对改善主燃区高温腐蚀区域的贴壁气氛效果显著,贴壁O_(2)体积分数由1.0%提高至2.7%左右,而还原性CO和H_(2)S的体积分数降幅分别达到70%和85%。A technology solution of near-wall air retrofit for a 660 MW ultra-supercritical opposed firing boiler,which had serious high-temperature corrosion problem,was proposed.It mainly contained high-speed nozzles located at the front and rear walls.Computational fluid dynamics(CFD)theory was used to evaluate the effect of the retrofit.The simulated data,such as temperature distribution and near-wall atmosphere at main combustion zone of the boiler before retrofit,correspond closed to the experimental results,so the correctness of numerical simulation is verified.The results show that if near-wall air percentage is low,the jet shows weak rigidity and would not penetrate the high-temperature and high-viscous flue gas.When the near-wall air percentage reaches more than 3%,the jet shows strong rigidity for its high momentum and initial velocity,which could reach the high-temperature corrosion zone.The near-wall air has little influence on the gas components at the main central zone,and only increases the oxidizing atmosphere near the side wall at main combustion zone.As a result,the area of water wall which has a tendency to occur high-temperature corrosion is reduced significantly.The in-situ measurement shows that near-wall air system is effective.After retrofit,the near-wall O_(2) volume fraction is greatly increased from 1.0%to 2.7%.Correspondingly,the CO and H_(2)S volume fractions are reduced by 70%and 85%,respectively.

关 键 词：高温腐蚀 贴壁风 计算流体力学 数值模拟 工程验证 

分 类 号：TK229.6[动力工程及工程热物理—动力机械及工程]