SCR脱硝系统导流板优化设置的数值模拟

根据某电厂SCR脱硝装置气流均匀性的设计要求,按1:1比例建立三维模型,划分网格后进行CFD仿真模拟,并根据模拟结果对比分析了速度相对标准偏差、最大烟气入射角度、温度最大绝对偏差、氨氮物质的量之比、系统压损5个参数,研究了关键位置导流板的优化设置规律。结果表明,在整个SCR脱硝装置烟道系统中,烟道入口处宜设置等间距导流板,以使气流均匀进入后部管道;烟道系统中任何有变径或变向的烟道均宜设置导流板,以防止气流偏向某一方;距离反应器最近处的烟道外形、导流板尺寸对气流均匀性影响最大;在反应器顶部加设干扰气流的小圆管,对改善局部区域气流均匀性有一定作用。

Numerical Simulation of Guide Plate Optimization Setting of Selective Catalytic Reduction Denitrification System

According to the design requirement of airflow uniformity of SCR denitration device in a power plant, established a three-dimensional model with a ratio of 1:1 and simulatedwith CFD after meshing. On the basis of the simulation result, contrasted and analyzed five parameters of speed relative standard deviation, the max flue gas incident angle, the temperaturemaximum absolute deviation, the molar ratio of NH3/NO and the systempressure loss, and investigated the guide plate optimal setting rule in the key positions. The results showed that in the SCR denitration system, it is necessary to set the equidistant guide plate at the flue entrance for uniform airflow into rear pipe, and the guide plates should also be set at the appropriate positions with reducing and changing direction to prevent the gas flow to one side. The guide plate size and the flue pipe shape nearest to the reactor have the most impact on the airflow uniformity. Installing the little pipe on the reactor top would improve local position air uniformity.