电除尘器阳极振打时粉尘层剥离与二次扬尘研究

发布时间：2018-07-05 07:12

本文选题：阳极板 + 粉尘层　；参考：《浙江大学》2017年硕士论文

【摘要】：目前,燃煤电厂锅炉尾气中细颗粒物的脱除主要采用静电除尘器。影响电除尘器收尘效率的主要因素是气流分布不均、离子风、振打等引起严重的二次扬尘。其中振打引起的二次扬尘最高可占电除尘器出口总排放浓度的90%。故降低振打时二次扬尘对提高除尘器收尘效率具有重大意义。电除尘器振打的研究主要集中在上世纪70、80年代,且研究方向主要集中在最小振打加速度、振打时的清灰效果和振打加速度的传递,鲜有研究粉尘层剥离过程的报道。为了研究不同条件下电除尘器阳极振打时粉尘层的剥离过程,设计了闭循环实验平台。用相机拍摄振打时粉尘层在阳极板上的剥离过程并用ELPI测试电除尘器出口浓度,确定最佳振打加速度和最佳振打粉尘层厚度,为工业应用中振打参数的设置提供依据。实验时测试不同条件下电除尘器的伏安特性曲线,实验表明:异极距越小,起晕电压越低,伏安特性曲线越陡;阳极板上粉尘层增厚会使电晕电流减小;粉尘层比电阻越大电流越小。此外,还对振打加速度进行标定,得到本实验装置振打加速度与振打高度的标准曲线。设置一系列的对照实验,研究振打时粉尘层的剥离过程,并探索剥离率和二次扬尘与粉尘层厚度、振打加速度、粉尘比电阻、振打时运行电压、收尘时运行电压的关系。结果表明:振打时粉尘层脱离阳极板时有颗粒状和团状,颗粒状会形成严重的二次扬尘随气流一起排出。就减少振打时二次扬尘而言,带电振打明显优于断电振打。此外,实验中还发现二次扬尘与剥离率呈正相关关系。对阳极板上粉尘颗粒和粉尘层进行受力分析,得出粉尘层脱离阳极板理论上需要的临界振打力,并分析理论公式难以应用的原因。拟合出不同条件下振打加速度与剥离率的关系,并求出剥离率为90%时的振打加速度,得到振打加速度与粉尘层厚度、振打时运行电压、比电阻的关系式。
[Abstract]:At present, electrostatic precipitator is used to remove fine particles from boiler tail gas of coal-fired power plant. The main factors affecting the dust collection efficiency of ESP are the uneven distribution of air flow, ion wind, vibration and other serious secondary dust. The secondary dust caused by vibration can account for 90% of the total discharge concentration at the outlet of the electrostatic precipitator. Therefore, it is of great significance to reduce the secondary hoisting dust during vibration beating to improve the dust collection efficiency of the dust collector. The research on the vibration of electrostatic precipitator is mainly focused in the 1970s and 1980s, and the research direction is mainly focused on the minimum vibration acceleration, the dust removal effect and the transmission of the vibration acceleration. There are few reports on the process of dust layer stripping. In order to study the stripping process of dust layer during anodic vibration of electrostatic precipitator under different conditions, a closed cycle experimental platform was designed. The peel process of dust layer on the anode plate was photographed by camera and the outlet concentration of ESP was measured by ELPI to determine the optimum vibration acceleration and the optimum thickness of the dust layer, which provided the basis for setting the vibration parameters in industrial application. The volt-ampere characteristic curves of the electrostatic precipitator under different conditions were measured in the experiment. The results show that the smaller the distance between the different poles, the lower the corona voltage, the steeper the volt-ampere characteristic curve, the thicker the dust layer on the anode plate, the less the corona current. The larger the dust layer resistance, the smaller the current. In addition, the standard curve of vibration acceleration and height was obtained by calibrating the vibration acceleration. A series of controlled experiments were carried out to study the stripping process of dust layer during vibration beating, and to explore the relationship between the stripping rate and the thickness of dust layer, the vibration acceleration, the specific resistance of dust, the operating voltage during vibration beating and the operating voltage during dust collection. The results show that when the dust layer breaks away from the anode plate, there are granular and mass shapes, and serious secondary dusts will be discharged along with the air flow. In terms of reducing secondary dusts, electrified vibration is better than power off. In addition, a positive correlation was found between the secondary dust and the stripping rate. By analyzing the force of dust particles and dust layer on anode plate, the critical vibration force of dust layer is obtained, and the reason why the theoretical formula is difficult to be applied is analyzed. The relation between vibration acceleration and stripping rate under different conditions is obtained, and the relation between vibration acceleration and dust layer thickness, operation voltage and specific resistance is obtained when peeling rate is 90.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X773

【参考文献】