高流场中微细粉尘荷电凝并粗化对电捕集效率的影响

Effect of Submicron Dust Charging and Coagulation on Efficiency of ESP in the High Flow

目前电除尘器存在微小颗粒粉尘捕集效率低、本体体积庞大和能耗高等问题。本文基于烟道中粒子动量高,放电通道中离子输运特性较好的特点,将离子源、荷电凝并装置设置于电除尘器前烟道中。实验结果表明,离子浓度随电场强度加大而增加;在高离子动量情况下,烟道中的离子浓度可达到1.97×109/cm3,比现有电除尘器的离子浓度高出2～3个数量级;矩形电晕极优于圆形电晕极,而芒刺电晕极起晕电压低,耗能少,产生离子浓度高且稳定,因此以芒刺电晕极为最佳;中位径为0.2μm的硅粉、中位径为6μm的滑石粉和两种粉体的混合粉等微细颗粒荷电凝并后被粗化为电除尘器有效捕集的颗粒,电捕集效率显著提高。本实验可在不增加电除尘器室数、不改变原有运行方式和运行参数条件下,有效解决现有电除尘器预荷电离子浓度过低问题,增大其捕集效率。

Due to the inefficiency of collecting submicron dust, the current electrostatic precipitator（ESP） suffers from disadvantages of great size and much consumed energy.This paper proposes to put the ion source and the charging and coagulation equipment in the flue, to secure a high ion transportation rate with high particle momentum.The results show that the ion density is increased with the increase of the electric field intensity.In the condition of high momentum, the ion density reaches 1.97×109/cm3, 2～3 orders of magnitude higher than that of ESP.Rectangular powered electrodes are shown to be better than circular powered electrodes.The prickle powered electrodes, with low corona onset voltage, consume less power and generate ions of high density in a stable way.So the prickle powered electrodes are the best choice.Median-particle-size of 0.2μm silicon powder, median-particle-size of 6μm talcum powder and the mixed powder of silicon powder and talcum powder were charged and coagulated to big particles.The efficiency of ESP is significantly improved.A charging system equal to a room of ESP can be saved.The problem of low efficiency of the current ESP can be solved without the need to increase the rooms of ESP and to change the running matter and the parameters, but only by making use of the high momentum of charging particles in the flue.