静电增强湿式除尘器捕集可吸入颗粒物的定量描述

湿式重力喷淋除尘器一般对可吸入颗粒物的除尘效率较差,而借助静电力,则有望改善湿式除尘器对细微颗粒的除尘效果.首先介绍了静电增强湿式除尘器的捕集机制,包括布朗扩散、拦截、惯性碰撞和静电捕集;然后利用事件驱动常体积法描述了典型火电厂中三峰分布的烟尘颗粒群的尺度分布函数的动力学演变过程,以此量化静电增强湿式除尘器的除尘过程.结果表明,典型的传统湿式重力喷淋除尘器对PM的分级除尘效率在5%以上;如果液滴荷电,有望使得该除尘器对PM的分级除尘效率达到70%以上;如果颗粒荷电,PM的分级除尘效率将在25%以上;在液滴和颗粒同时荷上相反电荷的静电增强湿式除尘器中,PM的分级除尘效率接近100%.

Quantitative Description of Removal Process of Particulate Matter in Gravitational Wet Scrubbers with Electrostatic Enhancement

Traditional gravitational wet scrubbers have low removal efficiency for particulate matters(PM),but the performance of the scrubbers for PM can be greatly improved by the help of electrostatic force.First,the removal mechanisms of scrubbers with electrostatic enhancement,that is,Brownian diffusion,interception,inertial impaction and electrostatic collection are introduced.Then event-driven constant volume method is used to describe the dynamic evolution of fly ash size distribution function with initial tri-model in typical power plants,in such a way that the removal process in wet scrubbers with electrostatic enhancement is described quantitatively.Numerical simulation shows that,in comparison to that the grade removal efficiency of PM in traditional wet scrubbers is above 5%,grade efficiency of PM in wet scrubbers with electrostatic enhancement reaches above 70% when droplet charging,above 25% when particle charging,and even near 100% when particle charging and droplet charging with opposite polarities.