微空腔雾化放电对PM2.5污染控制的实验研究

In the emission of air pollutants, particulate matters (PM2.5)and acid materials (SO2, NOx) often exist simultaneously. In the current environment improving process, it is a big problem how to control the two types of pollutants at the same time. A micro-cavity water electrode discharge system is proposed in this subject to investigate the I-V characteristic curve, the atomizing features of different liquid, the coagulation between atomized droplets and particulate matters andthe characteristics of the chemical reaction between liquid droplets and acid materials. The reactions will be compared under two different conditions such as atomization discharge and metal one, then the property's change of electrohydrodynamic in micro-cavity atomization can be discussed as well. In the experiment,non-invasive measurement method such as spectral measurements, ICCD imaging with short exposural time, optical target, optical power meter, and micro-pressure measurement,etc.will be used to analyze the spatial and temporal distributions and moving characteristics of ions in the process of atomization discharging and metal discharging. Absorbing energy effect from discharge will be confirmed for the discharge atomized droplets. The distribution rule of wind velocity and wind pressure will also be obtained. Furthermore, particle size distribution of collected dust and the change of acid rain materials' collecting efficiency are analyzed under different conditions.In order to find a optimizated condition, the electrostatic dust collecting and the lye absorpting methods will be investigated and an ideal combination of them will be found.This project is carried out mainly to improve the technology of low collecting efficiency for fine particulate matters.and to widen the controlling method of SO2.

在大气污染排放过程中，颗粒物(PM2.5)及酸雨物质（SO2、NOx）往往同时存在，如何同时治理这两类污染物质是目前环境治理过程中的难点问题。本课题将采用自主研发的微空腔水电极放电系统研究微空腔放电的伏安特性、不同液体的雾化特性、雾化液滴与颗粒物的凝并作用、荷电液滴与酸雨物质反应的特殊性以及上述反应在雾化放电与金属放电两种情况下的比较，讨论微空腔雾化放电电流体性质的变化。实验过程中，将利用光谱测量、ICCD 短时曝光成像、光学靶、光功率计、微压测量法等非介入式测量手段，分析雾化放电与金属放电过程中离子的时、空分布及运动规律。确定放电水雾对放电能量的吸收作用，电场中风速、风压分布规律。分析不同条件下捕集粉尘的粒径分布、对酸雨物质收集效率的变化，研究将静电除尘、碱液吸收两种方法有机结合的优化条件。该研究将解决大气中微细颗粒物收集效率低下的关键技术并拓宽 SO2 治理的手段。

在大气污染排放过程中，颗粒物(PM2.5)及酸雨物质（SO2、NOx）往往同时存在，如何同时治理这两类污染物质是目前环境治理过程中的难点问题。针对此问题，利用自主研发的微空腔水电极放电系统研究了微空腔放电的放电特性。在雾化放电情况下，研究了放电区域内气、液两相流的运动过程、凝并过程。分析了雾化放电过程中 Taylor 锥的形成、断裂及散射的过程变化，雾滴在靶标上的成像分布及运动轨迹，分析了泰勒锥锥角、长短轴关系、锥体形成与断裂周期等相关参数。研究了不同液体静电雾化过程中泰勒锥的形成与断裂形式，测量了不同电压和液体种类下液桥长度、液桥断裂后的平均粒径、雾化均匀度等参数。模拟了单个放电单元的放电特性，分析了放电空间液相物质存在对空间气流的影响。利用实验室环境代替除尘器环境对雾化静电除尘器进行模拟研究，以空腔电极结构为切入点，选取不同长度的直单空腔电极、不同分离角度的双空腔电极以及上、下偏离电极，在五种典型外加高电压下进行了静电雾化实验，从空腔电极的放电特性，静电雾化过程中的泰勒锥形貌、雾滴喷射效率、雾化周期时间分布、耗液量等角度出发，对各类空腔电极的性能进行了研究。本项目同时通过分析不同极配结构下的收集效率及粉尘粒径分布，研究了影响烧结烟气中微细颗粒物捕集效果的因素。本项目依据实验结果及研究结论寻找了提高微细粉尘（PM2.5）净化率、提高液体与气态污染物（SO2、NOx）反应效率的方法，为进一步实现研制同时治理两种污染物的设备提供了设计理念和理论指导。