基于非均匀入口条件的SCR氨喷射方法  

Ammonia injection method for SCR based on non-uniform inlet condition

作　　者：周英贵[1] 金保昇[1] 

机构地区：[1]东南大学能源热转换及其过程测控教育部重点实验室,江苏南京210096

出　　处：《华中科技大学学报（自然科学版）》2016年第4期121-126,共6页Journal of Huazhong University of Science and Technology(Natural Science Edition)

基　　金：国家自然科学基金资助项目(51276038)

摘　　要：为了提高选择性催化还原(SCR)脱硝系统烟气流场和还原剂浓度在反应器内分布的均匀性,以300MW四角切圆燃煤锅炉SCR系统为原型,基于更符合SCR工程实际的非均匀入口边界条件,采用数值模拟计算方法,分析不同氨喷射方法时还原剂的分布特性和标准偏差.结果表明:SCR入口NO通量偏差大,最大值为46.7%;弯道C布置4块导流板时,E-E截面速度偏差系数从18.13%降低到13.61%;SCR入口采用涡流板均匀喷氨时,E-E截面氨氮比标准偏差系数Ch为17.52%,调整为非均匀喷氨时,Ch为15.56%,不均匀性效果改善不明显;SCR入口采用喷氨格栅多喷嘴设置,且实行分区非均匀喷氨控制方法时,E-E截面的Ch降低至4.72%,对流场速度均匀性分布几乎没有影响,说明该方法是SCR系统还原剂有效控制方法.On the basis of the non-uniform inlet boundary conditions which was more in line with the SCR（selective catalytic reduction）engineering practice,a suitable CFD（computational fluid dynamics）model was built based on a commercial 300 MW tangentially coal-fired utility boiler′s SCR system in order to improve the uniform distribution characteristics of reducing agent in the tail flue on hybrid process.Measurements were conducted to analyze the trends and standard deviation of concentration distribution of reducing agent in ammonia different injection methods.Results show that the deviation of the NO flux in the entrance is relatively large with the maximum relative value close to 46.7%.Without guide plates,the velocity deviation factor on the E-E cross section of bend Chis 18.13%,while this value could be reduced to 13.61% by assembling 4guide plates on the bend Ch.Under the uniform injection mode of vortex board device,the standard deviation coefficient of the ammonia nitrogen ratio is 17.52%.Using a non-uniform injection method could reduce this coefficient to 15.56%,which is an unsatisfactory promotion.However,by combining the non-uniform mode with ammonia injection grid,it is observed that the standard deviation coefficient of ammonia nitrogen ration on the E-E cross section could be reduced to 4.72%,while the influence on the velocity distribution is negligible.All the results indicate that the non-uniform mode with ammonia injection grid is a effective control mode for the SCR system.

关 键 词：选择性催化还原 非均匀入口 速度分布 氨氮比 非均匀喷氨 偏差系数 

分 类 号：TK229[动力工程及工程热物理—动力机械及工程]