低温等离子体氧化水中难降解有机物研究

实验将介质阻挡放电与电晕放电组合在同一个反应器内,实验废水为直接大红染料溶液,将高压电极上通人50 Hz交流高压电,介质阻挡放电系统的电极间距为30 mm、电晕放电系统电极间距为25 mm、电源电压20 kV,利用常压空气中形成的雾化水电极介质阻挡放电/电晕放电低温等离子体及其活性基团作用于难降解有机物分子.实验分析了...     

Mn(Ⅱ)液强化电晕放电烟气脱硫效果

建立了线筒式电晕放电反应器,测定了其放电特性,研究了电压、水流量、Mn2+浓度和SO2浓度等对电晕放电与Mn(Ⅱ)液相催化协同脱硫效果的影响,并探讨了协同脱硫的反应机理.结果表明,脱硫效率随着放电电压、水流量和Mn2+浓度的增加而增加,SO2浓度的影响不明显.电晕放电与Mn(Ⅱ)液相催化协同能够加强SO2的氧化作用,提...     

翘片-筒式脉冲电晕流光放电装置对二氯甲烷的降解效果及其稳定性

传统结构线-筒式电晕放电装置在降解VOCs时生成的副产物会粘附在放电区域(线电极)上,使得放电间距减小,导致降解效果不稳定。翘片-筒式脉冲电晕流光放电等离子装置的电极结构可将放电区域(翘片尖端-筒)与副产物粘附区域(连接翘片的轴线)分开,从而维持装置的放电强度和稳定性。当翘片-筒式脉冲电晕流光放电反应器相邻翘片间距/放电间距为1,在37 kV下,反应器功率为0.95 W,能量体积密度为和23.6 mJ·L-1,为最优电极配置;处理二氯甲烷2 h后的降解效率呈现小幅度下降后稳定在35%。因此,放电形成的气溶胶部分沉积在凹槽处,可维持反应器稳定的放电强度及对二氯甲烷的降解效率。本研究结果可为低温等离子体处理VOCs废气的性能提升提供参考。     

电晕-介质阻挡协同放电降解连续流丙酮

利用自制等离子体反应器开展电晕-介质阻挡协同放电降解连续流丙酮研究,采用均匀设计法获得适宜的丙酮降解参数及其相互关联性,通过解析电晕-介质阻挡协同放电机理,结合丙酮降解热力学性能分析,获得影响丙酮降解的主要因素。结果表明:丙酮降解的适宜条件为反应器电压9.60kV、空气流量1.4L·min~(-1)、在丙酮气体流量20 mL·min~(-1)的连续流体系下,电晕-介质阻挡协同放电3 min、初始质量浓度为1.807 mg·L~(-1)的丙酮单次循环降解率可达35.01%。解析等离子体放电过程和热力学性质发现,丙酮降解受协同放电活性粒子与反应温度的双重影响。     

雾化电晕净化烹调油烟技术

对雾化电晕放电极雾化过程、荷电液滴的捕集原理、自清洗作用进行探讨,在相同电压下雾化负电晕放电电流高于干式负电晕放电电流,极间大量荷电液滴具有很高的荷质比,并高速向极板驱进,对烟尘具有静电凝并和动力凝并除尘作用,具有高效净化油烟、自清洗极板的功能,此项净化烹调油烟的新技术,优于传统油烟净化技术,具有很好的应用价值和前景。     

雾化电晕净化烹调油烟技术

对雾化电晕放电极雾化过程、荷电液滴的捕集原理、自清洗作用进行探讨,在相同电压下雾化负电晕放电电流高于干式负电晕放电电流,极间大量荷电液滴具有很高的荷质比,并高速向极板驱进,对烟尘具有静电凝并和动力凝并除尘作用,具有高效净化油烟、自清洗极板的功能,此项净化烹调油烟的新技术,优于传统油烟净化技术,具有很好的应用价值和前景.     

电晕放电等离子体对水中邻苯二甲酸二甲酯的降解

采用电晕放电等离子体降解水中的邻苯二甲酸二甲酯,研究了放电输出功率、溶液初始浓度、空气流量、初始p H、Fe2+和羟基自由基清除剂对邻苯二甲酸二甲酯去除效率的影响,并对其降解动力学进行了初步模拟。结果表明,电晕放电等离子体对水中邻苯二甲酸二甲酯有较好的去除效果。在放电功率45 W、初始浓度50 mg·L~(-1)、空气流速2 L·h-1、初始p H 6.31、初始电导率4.05μS·cm-1的条件下,反应30 min,邻苯二甲酸二甲酯的去除率可达到95%。酸性条件下有利于邻苯二甲酸二甲酯的降解。添加Fe2+,在反应初期可显著提高邻苯二甲酸二甲酯的降解率。羟基自由基清除剂的加入在一定程度上抑制了邻苯二甲酸二甲酯的降解。电晕放电等离子体降解邻苯二甲酸二甲酯的过程基本符合一级反应动力学。     

介质阻挡放电与脉冲电晕放电修复芘污染土壤的对比研究

选取芘作为多环芳烃的代表污染物,利用介质阻挡及脉冲电晕2种放电方式产生的低温等离子体对芘污染的土壤进行修复。通过污染物处理率、影响因素和能量利用效率等实验计算结果对2种放电方式下土壤的修复效果进行比较,并从放电方式的原理、特点和反应器结构等角度进行分析。结果表明:在芘初始浓度为100 mg·kg~(-1)、电极间隙为14 mm时,介质阻挡放电对土壤中芘的处理率较高,可达60.6%,经GC-MS图谱检测分析,其多数产物分子量小、结构简单,但该放电方式受电气参数影响较大,当电极间隙增大到20 mm时,处理率则低至28.3%,其最高能量效率仅为0.321 mg·k J~(-1);而脉冲电晕放电在不同条件下处理效果稳定,电极间隙为14~20 mm时,处理率均能达50%左右,且在不同实验条件下,其能量效率为2.29~3.76 mg·k J~(-1),是介质阻挡放电的10余倍。脉冲电晕放电方式在处理比污染土壤时要优于介质阻挡放电。     

GJX-~5/100型高压静电吸尘器介绍

浙江金华电子仪器厂生产的GJX-~5/_(100)型高压静电吸尘器,具有单通道、宽极距、超高压等特点.这种收尘器的收尘方法是:将含尘空气集中于收尘罩内,罩内悬挂一电晕极线,并通以高压直流电(一般收尘罩接正极,并良好接地.电晕线接负极与地要很好绝缘).利用电晕线周围的电晕放电,产生大量的、高速运动的电子与正负离子,去碰撞     

公路隧道空气污染治理的研究进展

本文介绍了公路长隧道空气污染状况、治理现状及其研究进展,文中指出脉冲电晕放电法治理隧道空气污染是有效的和可行的。     

Novel hybrid composite discharge electrode for electrostatic precipitator

Over the last few decades, electrostatic precipitators (ESPs) have emerged as effective air pollution control devices for treating coal-fired power plant exhausts. Among the components of the ESP, the discharge electrodes are extremely important in determining the collection efficiency of the ESP. Typically, in wet ESPs, the discharge electrodes used must be made of corrosion-resistant alloys, which makes them extremely expensive and heavy. Hybrid composite discharge electrodes have the potential to be lightweight and corrosion-resistant substitute for traditional metal alloy electrodes used in wet ESPs. In this experimental study, a novel hybrid composite electrode (recently patented at Ohio University) is presented as a substitute for traditional metal electrodes in wet ESPs. The samples of hybrid electrodes were fabricated by using carbon fiber composites, combined with metal mesh, in the shape of a long and thin tape. The electrode’s electrical response was evaluated in open atmospheric conditions, while connected to a transformer-rectifier unit to generate a corona current at voltages exceeding 50 kV. Results of these hybrid electrodes were compared with traditional metal electrodes. The hybrid composite discharge electrode produced a uniform corona at comparable power levels to that of metal electrodes, with additional advantages of being compact, lightweight, and highly corrosion resistant. In addition, hybrid composite electrodes exhibited lower corona onset voltage as compared with metal electrodes. The preliminary experimental data are encouraging and show significant potential for this new inexpensive hybrid electrode to replace metal electrodes in wet ESPs, providing comparable (and in some cases exceeding) collection efficiencies with lower ozone generation.

Implications: The newly invented hybrid composite electrode (HCE) performance was evaluated through experimentation with conventional metal electrodes. The HCE performance was comparable to the metal electrodes. The HCE also exhibited uniform corona fields and steady power while maintaining similar and in some cases superior electrical performance as compared with metal electrodes and thus shows a significant potential to substitute metal electrodes in wet ESP systems.     

Decomposition of volatile organic compounds using corona discharge plasma technology

This paper explores the application of corona plasma technology as a tool in treatment of volatile organic compounds (VOCs). The review introduces the principle of corona discharge and describes the characteristics of plasma, especially of various corona plasma reactors. By summarizing the main features of such reactors, this paper provides a brief background to different power sources and reactor configurations and their application to VOC treatment design. Considering chlorinated compounds, benzene series and sulfur compounds, this paper reveals the probable mechanism of corona plasma in VOC degradation. Additionally, the effects of numerous technical parameters – such as reactor structure, shape and materials of electrodes, and humidity – are analyzed comprehensively. Product distribution, energy efficiency and economic benefits are invoked as factors to evaluate the performance of VOC degradation. Finally, the practical application of corona plasma and its advantages are briefly introduced. The review aims to illustrate the enormous potential of corona plasma technology in the treatment of VOCs, and identifies future directions.

Implications: This paper comprehensively describes the principle, characteristics, research progress and engineering application examples of the degradation of volatile organics by corona discharge plasma, to provide a theoretical basis for the industrial application of this process.     

Fine particle migration and collection in a wet electrostatic precipitator

Electrostatic precipitation is considered as an effective technology for fine particle removal. A lab-scale wet electrostatic precipitator (ESP) with wire-to-plate configuration was developed to study particle migration and collection. The performance of the wet ESP was evaluated in terms of the corona discharge characteristics, total removal efficiency and fractional removal efficiency. The corona discharge characteristics and particle removal abilities of the wet ESP were investigated and compared with dry ESP. Particle removal efficiency was influenced by discharge electrode type, SO₂ concentration, specific collection area (SCA) and particle/droplet interaction. Results showed that the particle removal efficiency of wet ESP was elevated to 97.86% from 93.75% of dry ESP. Three types of discharge electrodes were investigated. Higher particle removal efficiency and larger migration velocity could be obtained with fishbone electrode. Particle removal efficiency decreased by 2.87% when SO₂ concentration increased from 0 ppm to 43 ppm as a result of the suppression of corona discharge and particle charging. The removal efficiency increased with higher SCA, but it changed by only 0.71% with the SCA increasing from 25.0 m²/(m³/s) to 32.5 m²/(m³/s). Meanwhile, the increasing of particle and droplet concentration was favorable to the particle aggregation and improved particle removal efficiency.

Implications: This work tends to study the particle migration and collection under spraying condition. The performance of a wet electrostatic precipitator (ESP) is evaluated in terms of the corona discharge characteristics, total particle removal efficiency, and fractional particle removal efficiency. The effects of water droplets on particle removal, especially on removal of particles with different sizes, is investigated. The optimization work was done to determine appropriate water consumption, discharge electrode type, and specific collection area, which can provide a basis for wet ESP design and application.     

脉冲电晕反应器结构对乙硫醇消除效果的影响

研究了脉冲电晕等离子体反应器结构的变化对乙硫醇消除效果的影响规律。结果表明,在反应器内设置折流板,可以增加气流的湍动程度,有利于活性粒子与污染物的充分接触,从而提高消除率。高压电极间距对电晕区范围及消毒效果有较大影响,间距较小将导致各电极产生的电场相互干扰明显,消除率减小;而电极间距过大,虽然电极间电场分布相互干扰小,但是反应器内可排布的电极数减少,总电晕区减少,消除率也减小。根据实验结果,电极间距设置为50 mm比较合理。另外,在相同的电场强度和脉冲频率下,毛刺形高压电极比线电极结构能耗低,能量利用率高。     

Laboratory and field measurements of NOx produced from corona discharge

This research consists of a laboratory study and a field study. The laboratory research reports the formation of NO_x from a point to plane corona discharge. Discharge polarity and relative humidity determined the amount of NO_x that was produced. The positive point discharge caused more NO_x to form than the negative point discharge. For both polarities NO_x production showed a nonlinear increase with current. Relative humidity enhanced the NO_x formation for both polarities. In each case, the amount of NO_x formed was comparable to the quantity of N₂O produced from corona discharge. The research also reports the results from a field study that measured the amounts of 03 and NO₂ produced by corona discharge during a thunderstorm. The study found that the ambient concentrations of 03 and NO₂ increased several fold due to corona discharge and returned to original levels after the thunderstorm.     

Ozone Generation in an Electrostatic Precipitator With a Heated Corona Wire

The body of information in this paper is directed to individuals involved in the design of electrostatic precipitators or of any devices utilizing the corona discharge where the ozone generation is considered to be a problem. A method that gives as much as 85 % reduction in the ozone generation per unit corona current for a given corona wire is described. The electrical parameters governing the formation of O₃ in an electrical discharge are summarized. It is shown that a reduction in the average gas density in the ionized sheath of a corona discharge should lead to lower O₃ generation. Experiments were carried out with an a.c. heating current being used to heat a corona wire in a cylindrical geometry corona section. It was found that as the heating power applied to the wire increased, the O₃ generation per unit corona current decreased for both positive and negative corona. An experimental formula was obtained that relates the heating power to the O₃ generation with and without heating for positive corona. This formula was based upon experimental work carried out on corona wires of different materials and sizes and at flow conditions typical of two-stage electrostatic precipitators. The reduction in the O₃ concentration is believed to be caused primarily by the reduced corona power dissipated in the ionized sheath under heating conditions. These results have great practical importance for improving the performance of the two-stage type electrostatic precipitator as it allows the corona current and hence charging efficiency of the unit to be increased without exceeding the O₃ limits.     

脉冲电晕法脱硫脱硝研究概述

本文概述了脉冲电晕脱硫脱硝研究所得的重要成果，着重总结了国内外有关电晕特性、反应机理、电源与反应器系统研究所得的重要结论。最后对该技术的前景作一展望。     

泛比电阻电除尘器收尘性能实验研究

泛比电阻电除尘器是一种具有辅助电极和交错平板收尘电极的新型电除尘器.通过对其伏安特性及除尘效率的试验研究,并与传统线板式静电除尘器进行比较,结果表明辅助电极对电晕电流具有明显的抑制作用,在相同的外加电压下,泛比电阻电除尘器对高比电阻锅炉飞灰的收尘效率比普通的线板式电除尘器明显要高.     

直流电晕放电降解甲苯的特性研究

利用直流高压电晕产生的非平衡等离子体分解甲苯.考察了各种因素对甲苯降解效率的影响,并对降解机理进行分析.研究结果表明:放电时间的延长、放电电压的提高、适宜的相对湿度和较低甲苯的初始浓度都有利于提高甲苯的降解效率.