湿式电除尘器性能测试方法及排放特征研究

Study on Performance Testing Method and Emission Characteristics of Wet Electrostatic Precipitators

湿式电除尘器收尘极被水膜覆盖,放电区域存在水雾,无振打二次扬尘,且细颗粒物团聚现象显著,可有效减少细颗粒物、SO_3等排放。采用一体化采样头(内置滤膜)采集颗粒物,采用重量法(PM-10)和电荷法(ELPI)测定PM_(2.5);采用冷凝法或冷凝法与异丙醇吸收相结合的采样方法测定SO_3。测定结果表明,不同型式的湿式电除尘器颗粒物、PM_(2.5)一般分别在2～5 mg/m^3及3 mg/m^3以下,除尘效率一般在75%～95%,金属极板湿式电除尘器为连续喷淋,因不存在细颗粒物的二次扬尘,颗粒物排放可达1 mg/m^3以下;不同型式的湿式电除尘器SO_3排放一般在5 mg/m^3以下,SO_3脱除效率一般在60%～80%,导电玻璃钢湿式电除尘器板电流密度一般比金属极板湿式电除尘器大,因此其SO_3脱除效率普遍更高一些。

Due to the water film covered dust collecting electrode,the existence of water mist in the discharge area and the absence of vibration and secondary dust extraction,particularly its mechanism to agglomerate the fine particles significantly,the wet electrostatic precipitator(WESP)is very effective to reduce the emission of fine particles such as SO3.Particulate matter is collected by integrated sampling head(built-in filter membrane),while PM2.5 is determined by gravimetric method(PM-10)and charge method(ELPI),and SO3 is determined by condensation method or condensation method combined with isopropanol absorption.The results show that the concentration of particulate matter in different types of WESP varies from 2mg/m^3 to 5 mg/m^3,and PM2.5 is lower than 3 mg/m3 with the dust removal efficiency around 75%~95%.Continuous spray is applied in the metal plate type wet electrostatic precipitator.Since there is no secondary dust of fine particles,the emission of particulate matter is kept below 1mg/m3.The emissions characterization of SO3 in different types of WESP is generally below 5mg/m^3,with the SO3 removal efficiency about 60%~80%.The current density of conductive fiberglass WESP is generally greater than that of metal plate WESP,hence its SO3 removal efficiency is generally higher.