相变凝聚器对湿式电除尘器烟气均流效果分析

Analysis of the effect of PTC on the uniformity of flow velocity of wet electrostatic precipitator

湿式电除尘器入口处烟气流速的均匀性是影响其除尘效率的主要因素之一。基于多孔介质模型,对湿式电除尘器内部进行冷态流场数值模拟,并与试验测量结果对比;将无整流结构工况下的湿式电除尘器内部的模拟结果与仅添加格栅工况下的模拟结果对比;然后在整流格栅下方添加相变凝聚器后进行模拟,并与试验测量结果对比。结果表明:将湿式电除尘器简化为多孔介质模型合理;湿式电除尘器仅添加格栅,可使除尘器入口烟气流速分布趋于均匀,但并不能达到设计要求;同时添加格栅和相变凝聚器时,复合净化装置本体流场速度平均值为2.425m/s,相对偏差率为0.143,达到烟气流场气流均布系数≤0.2的设计要求,且与理论数值模拟结果吻合。

The uniformity of the flue gas flow rate at the inlet of the wet electrostatic precipitator(WESP)is one of the main factors affecting the dust removal efficiency. Based on the porous medium model, the numerical simulation of the cold flow field inside the WESP is carried out and compared with the experimental measurement results;the simulation results inside the WESP under the condition of no rectification structure and the addition of the grid only was compared, then a PTC is added below the rectification grid and the simulation result was compared with the experimental measurements. The results show that it is reasonable to simplify the WESP into a porous medium model;the WESP with grid only can make the flow velocity distribution at the WESP inlet tend to be uniform, but it cannot meet the design requirements;when the PTC is used, the average flow field velocity of the WESP is 2.425m/s, the relative deviation rate is 0.143, meeting the design requirement of the airflow field uniformity coefficient≤0.2 and fitting well with the result of numerical simulation.