基于非均匀入口条件的SCR氨喷射方法

发布时间：2018-11-24 21:08

【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.
[Abstract]:In order to improve the uniformity of flue gas flow field and reducing agent concentration in the selective catalytic reduction (SCR) denitrification system, the 300MW quadrangle tangential coal-fired boiler SCR system was used as the prototype. Based on the non-uniform inlet boundary conditions which are more in line with the actual conditions of SCR engineering, the distribution characteristics and standard deviation of reductant in different ammonia injection methods are analyzed by numerical simulation. The results show that the deviation of NO flux at the entrance of SCR is large, the maximum value is 46.7.The velocity deviation coefficient of E-E section decreases from 18.13% to 13.61 when the four guide plates are arranged in bend C. The standard deviation coefficient of ammonia nitrogen ratio of E-E section is 17.52 when the swirl plate is uniformly sprayed at the entrance of SCR, and the Ch is 15.56 when adjusted to non-uniform ammonia spray, the effect of inhomogeneity is not improved obviously. When the inlet of SCR is set with multiple nozzles with ammonia spray grille and the method of zone non-uniform ammonia spraying is implemented, the Ch of E-E section is reduced to 4.72, and the velocity uniformity distribution of the flow field has little effect on it. It shows that this method is an effective control method for reducing agent in SCR system.
【作者单位】：东南大学能源热转换及其过程测控教育部重点实验室;
【基金】：国家自然科学基金资助项目(51276038)
【分类号】：X773

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