【作者】 陈海丰；

【导师】 朱益民；

【作者基本信息】 大连海事大学 ， 环境科学， 2009， 博士

【摘要】 本文提出新型的针阵列双极电晕放电发生技术。对多针双极电晕放电伏安特性进行了细致实验研究和理论分析,并确定了其优化的电极间距。使用光学发射光谱确定了多针双极电晕放电形貌,并获知其微观特性与放电电流和外加电压的关系。实验研究了针阵列双极电晕放电对颗粒物的捕集效果,分析了其高效荷电和高效捕集颗粒物的机理。并在餐饮油烟,高温除尘和炭烟捕集上进行实际应用试验,得到良好的捕集效率和运行可靠性。首先总结了现有的电晕放电发生方式及其研究现状,指出一般的直流电晕放电可注入放电能量较低,而脉冲电晕放电虽然放电强度有效提高,但存在电源效率低、负面放大效应和脉冲元件寿命等问题。然后总结了国内外光学发射光谱OES法研究电晕放电主要结果,得到对放电区形貌、及其与宏观参数之间关系的研究较少,主要研究集中在单极电晕放电,对双极电晕放电尚未有相关研究。最后分别综述了电晕放电在颗粒捕集、脱硫脱硝以及VOCs降低中的应用研究,认为对各种污染物的净化效率有待进一步提高,主要包括微细颗粒捕集效率低、脱硝效率低、一些难分解的VOCs去除效率低,所以有必要和其他技术结合来提高净化效率。同时认为电晕放电在污染气体处理中,一方面需要提高其放电强度,另一方面需要提高其运行可靠性。提出一种高压电极和接地电极同为针阵列电极的新型双极电晕放电发生技术。分析认为:该放电同时产生正负电晕放电:具有更大的放电电流和功率密度;避免单极放电中电极积尘影响正常放电,具有更长的运行稳定性。通过考察相邻针尖间距s,电极间距d,和针尖半径a等参数对其伏安曲线的影响,细致研究多针双极电晕放电伏安特性。分析其具有更大的放电电流、更高的电子和离子密度的原因,得出其迁移区中同时存在正负离子,且正负离子的复合可以忽略。通过研究相邻针尖间距s,电极间距d和针尖半径a与放电功率密度的关系,得出有效提高放电功率密度的方法。并以放电稳定性为依据,确定多针双极电晕放电的优化电极结构和尺寸。在发射光谱诊断研究多针对板电晕放电的基础上,对多针双极电晕放电的放电形貌进行研究。测量电离区N₂第二正带跃迁的谱峰I_SPB,确定其两个电离区的放电形貌,获知其高能电子分布,并得到I_SPB在电离区体积分与放电电流成线性关系。再结合伏安特性研究得到,多针双极电晕放电正负电晕电离区中形成电流的带电粒子为高能电子,迁移区中形成电流的带电粒子为上下负离子。利用前述研究结论,研制成两套以针阵列双极电晕放电为核心技术的空气净化装置。分别进行处理空气一次性通过净化装置捕集颗粒物实验和在封闭室内净化装置捕集颗粒物试验。研究运行参数（风速、外加电压）和颗粒物粒径对净化装置处理效率的影响。比较针阵列双极电晕放电与针对板电晕放电捕集颗粒物效果,得到两种放电方式都能高效去除粒径较大的颗粒物,而针阵列双极电晕放电对微细颗粒物效果更好。结合微粒荷电理论,分析了针阵列双极电晕放电对微细颗粒高效荷电和捕集的原因。最后以针阵列双极电晕放电为核心技术,研制成多种废气净化装置,分别试用或应用于餐饮油烟净化、高温除尘和碳烟捕集,分别考察其净化效果。得到净化装置主要特点为:微细颗粒捕集效率高、运行稳定、整机结构简单、造价低。更多还原

【Abstract】 This thesis has proposed a novel corona discharge,i.e.,the needle matrix bipolar corona discharge.The current-voltage characteristics of the multi-needle bipolar corona discharge have been obtained through detailed experiment and analysis,and the optimum electrode structure has been determined.Using optical emission spectrometry. the outline of the multi-needle bipolar corona discharge has been determined,and some important roles between the microscopic characteristics and the discharge current and the applied voltage have been obtained.The efficiency of particles trapping by the needle matrix bipolar corona discharge has been studied experimentally,and the reasons why this kind of corona discharge has a high efficiency of charging and trapping particles have been analyzed.Using this technology in cooking fume purification, high-temperature precipitation and soot trapping,the results of the tests show that this technology has advantages of high trapping efficiency and running reliability.Firstly,summarize all the normal methods for producing corona discharge,and point out that the injecting discharge energy in DC corona discharges is low.while pulse corona discharge has shortages of low power efficiency,negative magnifying effects and short lifetime of pulse elements.Then,introduce the status of researching corona discharge using OES.It is concluded that main researches focus on uniform corona discharge,there is few research on morphology determination of ionization region and the relationship with macro parameters,and especially there is no study of bipoplar corona discharge.Finally,summarize the main application research status of corona discharge in environmental pollution treatment,including particle trapping. desulfurization and denitrification,and VOCs degradation.All results show that the removal efficiency needs to be improved. and the main problems are low trapping efficiency of micro-particles,low denitrification efficiency and low degradation efficiency of some VOCs.Thus,it is necessary to combine with other purification technologies,and it is believed that both the discharge intensity and the running reliability should be improved in purification of polluted gases using corona discharge. A method for producing bipolar corona discharge in needle matrix electrode configuration is proposed.It is thought that this kind of discharge produce positive and negative discharges simultaneously;has large discharge current and high power density; and has long running stability,e.i..resolve the problem of dust accumulation on the discharge electrodes in unipolar corona discharge.The current-voltage characteristics of the multi-needle bipolar corona discharge are studied in detail.Through regulating the space between needles s,the space between electrodes d and the needle radius a,the curves of current-voltage have been analyzed experimentally.The reasons why this kind of corona discharge has larger discharge current and higher electron and ion densities are obtained.It is concluded that there exist positive ions and negative ions in the migration area simultaneously,and the combination between positive ions and negative ions is ignored.Through comparing the relationships between the discharge power density and s.d, or a,it is gotten to increase discharge power effectively.Meanwhile,considering the discharge stability,the optimum electrode structure of the bipolar corona discharge is determined.Based on the study of multi-needle to plate corona discharge using optical emission spectrum,the morphology of multi-needle bipolar corona discharge is determined.According to the distribution of N₂ second positive band’s intensity I_SPB,the outline of the two ionization regions are drawn and the distribution of energetic electrons is obtained too.There is linear relationship between the sum of I_SPB and the discharge current I.Combined with the study of the current-voltage characteristics,the energetic electrons in the ionization regions and the ions in migration area are to form the discharge current in the multi-needle bipolar corona discharge respectively.According to the former conclusions,using the needle matrix bipolar corona discharge as a core technology,two sets of air cleaning devices are made.The experiments of particles trapping in one way and the test of air cleaning in a closed room have been conducted respectively.The effects of the wind velocity,the applied voltage and the diameters of particles on the trapping efficiency are studied experimentally.Comparing the efficiencies of trapping particles using needle matrix to plate discharge and needle matrix bipolar corona discharge,the fact is despited that these two discharges both have high efficiencies of trapping particles with large diameter,and the needle matrix bipolar corona has a higher efficiency of trapping particles with small diameter.Combined with the theory of particle charge,the reasons why the needle matrix bipolar corona discharge has high charge capacity and trapping efficiency is analyzed.Finally,using the needle matrix bipolar corona discharge as a core technology, several purification devices are made for applying in cooking fume purification. high-temperature precipitation and soot trapping.The removal efficiencies are investigated experimentally.The purification devices are characterized by high trapping efficiency of micro-particles,high running stability,simple structure and low manufacture cost.更多还原