蜂窝湿式静电脱除燃煤细颗粒物实验研究

发布时间：2018-04-03 08:36

本文选题：湿式静电除尘　切入点：细颗粒物　出处：《中国计量学院》2016年硕士论文

【摘要】：静电除尘器广泛应用于燃煤电厂的烟气治理系统,但其对可吸入颗粒物,尤其是细颗粒物的捕集效率并不高,难以达到现排放标准。湿式静电除尘技术采用水膜清灰方式代替了传统的振打清灰方式,可有效避免“二次扬尘”与“反电晕”现象,实现燃煤烟气细颗粒物排放的高效控制。对湿式静电除尘规律的研究有利于探索除尘机理,也能为工程应用中湿式电除尘设备的优化和设计提供指导。本文主要通过理论分析和实验测量的方法,研究蜂窝管状湿式静电除尘的放电特性规律以及除尘机理,主要研究内容包含以下三个部分:首先是对湿式静电除尘理论的研究,主要介绍了颗粒物在静电场中的荷电规律和收尘规律,并分析了粉尘颗粒与雾滴、粉尘颗粒与粉尘颗粒之间的相互作用,为湿式静电除尘实验研究提供指导。其次从清灰方式、极线形式、烟气含尘浓度着手,对蜂窝湿式静电放电特性进行实验研究。实验结果表明干式、溢流下湿式静电除尘器的放电特性区别不大,喷淋量的增加在一定程度上使电晕电流增大。在相同运行电压下,十二角锯齿星形极线在三种形式极线中电晕电流最大,六角锯齿星形极线其次。烟气含尘浓度的增加使荷电粉尘颗粒数目增加,自由电子与负离子数目减少,电晕电流降低。最后研究湿式静电的清灰方式、运行参数、本体参数和电源参数对细颗粒物脱除效率的影响。采用大流量重量撞击器(DGI)对除尘器颗粒物浓度进行测试,实验结果发现喷淋清灰方式对细颗粒物脱除效率最高,溢流清灰方式其次。提高比收尘面积和运行电压均可使除尘效率增加,当负载电压为18kV时,随着比收尘面积的增加,除尘效率由79%上升至92%。通过观察颗粒物分级脱除效率发现,粒径段在0.5μm-1μm的颗粒物脱除效率较低。当烟气含尘浓度达到较高值(442.85mg/m~3)时,除尘器仍可保持较高的除尘效率。
[Abstract]:Electrostatic precipitator (ESP) is widely used in flue gas control system of coal-fired power plants, but its capture efficiency for respirable particulates, especially fine particles, is not high, so it is difficult to meet the current emission standards.The wet electrostatic dust removal technology uses water film to remove ash instead of the traditional vibration dusting method, which can effectively avoid the phenomenon of "secondary dust raising" and "back corona", and realize the high efficiency control of fine particulate matter emission from coal-fired flue gas.The study on the law of wet electrostatic dust collection is beneficial to the exploration of dust removal mechanism, and can also provide guidance for the optimization and design of wet electrostatic precipitator in engineering application.Through theoretical analysis and experimental measurement, this paper mainly studies the discharge characteristics and dust removal mechanism of honeycomb tubular wet electrostatic precipitation. The main research contents include the following three parts: first, the research on wet electrostatic dust collection theory.This paper mainly introduces the charge law and dust collecting law of particles in electrostatic field, and analyzes the interaction between dust particles and droplets, dust particles and dust particles, which provides guidance for the experimental study of wet electrostatic dust collection.Secondly, the characteristics of honeycomb wet electrostatic discharge are studied from the aspects of ash cleaning, pole line and dust concentration.The experimental results show that the discharge characteristics of the wet electrostatic precipitator under dry and overflow conditions are not different, and the increase of spray amount increases the corona current to a certain extent.Under the same operating voltage, the corona current of the zigzag star pole line is the largest among the three forms, and the hexagonal zigzag star pole line is the second.With the increase of dust concentration in flue gas, the number of charged dust particles increases, the number of free electrons and negative ions decreases, and the corona current decreases.Finally, the effects of cleaning mode, operation parameters, bulk parameters and power supply parameters on the removal efficiency of fine particles were studied.The particle concentration of dust precipitator was measured by DGI. The results showed that the removal efficiency of fine particles was the highest by spray cleaning and the second was by overflow.When the load voltage is 18kV, the dust removal efficiency increases from 79% to 92% with the increase of specific dust collection area.It was found that the particle removal efficiency of 0.5 渭 m ~ (-1) 渭 m was lower when the particle size was 0.5 渭 m ~ (-1) 渭 m.When the dust concentration of flue gas reaches a high value of 442.85 mg / m ~ (3), the dust collector can still maintain a high dust removal efficiency.
【学位授予单位】：中国计量学院
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X773

【相似文献】