低负荷下SCR脱硝系统入口烟道补燃特性的数值模拟研究  

Numerical Simulation of Supplementary Combustion Properties in Entrance Flue of SCR Denitrition System of Low Load

作　　者：王廷燚 龚德鸿[1] 蒋松 程含含 WANG Ting-yi;GONG De-hong;JIANG Song(Electrical Engineering College,Guizhou University)

机构地区：[1]贵州大学电气工程学院,贵州贵阳550025

出　　处：《电站系统工程》2022年第2期1-4,共4页Power System Engineering

基　　金：贵州省自然科学基金项目(黔科合基础[2019]1059)资助。

摘　　要：针对锅炉机组在深度调峰过程中,SCR脱硝催化剂无法应用于低烟温的问题,以某660 MW火电厂SCR脱硝系统入口烟道为研究对象,基于CFD仿真软件,对该电厂通过焦炉煤气在脱硝系统入口烟道补燃提升烟温的过程进行了数值模拟。对比分析了锅炉机组50%负荷下,该段烟道出口过量空气系数为1.19、1.20、1.21、1.22、1.23,焦炉煤气量为1296 Nm^(3)/h、1368 Nm^(3)/h、1440 Nm^(3)/h、1512 Nm^(3)/h、1584 Nm^(3)/h等工况下烟道内温度分布及NO的排放情况,并在此基础上探究了机组负荷为45%、40%时烟道内温度分布特性。结果表明:焦炉煤气补燃能有效提升烟温,NO排放量有所下降,当过量空气系数为1.21时,补燃效果最好,随燃料量的增加,补燃温度呈线性升高趋势,且当烟温为586.01 K时,NO排放量最小为413 mg/Nm^(3);随着锅炉负荷的降低,燃烧区内温度分布的均匀性变差。In view of the problem that SCR denitration catalyst cannot be applied to low temperature conditions when the boiler units deep peaking,with the entrance flue of SCR denitrition system of a 660 MW thermal power plant as the study subject,based on CFD software,the process of coke oven gas supplementary combustion in the entrance flue of SCRdenitrition system to improve the flue gas temperature was simulated.When the load condition of boiler unit is 50%,excess air coefficient of the flue outlet is 1.19,1.20,1.21,1.22,1.23,and the coke oven gas is 1296 Nm^(3)/h,1368 Nm^(3)/h,1440 Nm^(3)/h,1512 Nm^(3)/h,1584 Nm^(3)/h,the temperature distribution and NO emission were comparatively studied.Meanwhile,the properties of smoke temperature distribution under 45%and 40%load were investigated.The results indicate that using coke oven gas in the flue to complementary reignite can increase smoke temperature and reduce NOemissions.When the excess air coefficient is 1.21,the effect of the supplemental combustion is the best.Increasing fuel amount can improve smoke temperature linearly,and when the smoke temperature is 586.01K,the minimum NOemission is 413 mg/Nm^(3).With the decrease of boiler load,the uniformity of temperature distribution in combustion zone becomes worse.

关 键 词：低负荷 SCR脱硝 烟道补燃 烟温 数值模拟 

分 类 号：TK227[动力工程及工程热物理—动力机械及工程]