【作者】 杨树；

【导师】 朱益民；

【作者基本信息】 大连海事大学 ， 环境科学， 2011， 博士

【摘要】 室内空气污染物具有复杂、多样、长期性和低浓度等特点,等离子体空气净化可快速、高效降低室内多种污染物。采用的主要等离子体发生技术为电晕放电,但电晕放电会同时产生少量的有害产物包括03和N02,形成二次污染。在实验室前期研究基础上,本文系统分析多针对板电晕放电电离区的微观特性；利用光学发射光谱(OES)法,对放电产生OH自由基进行优化研究,为后续以针阵列对板电晕放电为核心技术的空气净化单元研制提供设计依据。然后以降低放电产生的有害产物为研究目标,实验研究有害副产物N02与03产生,并采用Mn02催化剂催化降低N02及03。通过封闭空间内实验研究和应用试验,获知放电产生N02与O3相关规律及其去除规律,并确定室内空气净化装置的设计依据和运行参数。首先,根据发射光谱法(OES)对多针对板电晕放电的测量结果,对相应的实验数据进行统计、拟合和理论分析。得到高压针电极周围N2第二正带跃迁谱峰(ISPB)光强分布的等光强线曲线方程；获知电离区ISPB的分布,从而确定电离区内ISPB×S、电子平均速度、电流密度等微观电参数的变化关系,系统分析多针对板正、负电晕放电电离区和迁移区中微观物理特性。然后,以激发态OH自由基为研究对象,利用OES技术分别研究正、负电晕放电中,放电功率、电极间距和相对湿度等放电电参数对产生激发态OH自由基的影响。在稳定放电条件下,获知产生激发态OH自由基的优化运行参数,确定宏观参数与OH自由基之间的相关规律。为了使针阵列对板电晕放电适用于室内空气净化,本论文重点考虑放电产生有害副产物带来的安全问题。首先研究放电产生NO2的相关规律,主要包括放电功率、放电极性、电极间距和相对湿度等参数对NO2产生量的作用,并得到一些参数设计依据和定性运行依据。在此基础上,采用MnO2作为活性成分、SiO2-活性碳做载体的催化剂对放电产生的NO2进行去除实验研究。在不同放电功率P、不同相对湿度RH和不同放电极性等放电条件下,研究Mn02催化剂用量与NO2去除效率的关系。获知采用MnO2催化剂有效降低NO2的方法及其运行规律。其次进行针阵列对板电晕放电产生O3及催化降低O3的研究。在不同放电极性下,通过观测封闭小室内电晕放电产生的有害副产物O3浓度变化,总结出电晕放电产生O3的相关规律。采用MnO2作为活性成分、SiO2-活性碳做载体的催化剂对放电产生的O3进行去除实验。在不同放电功率P和不同放电极性等放电条件下,研究MnO2催化剂用量与O3去除效率的关系。获知MnO2催化剂作用下O3去除的相关规律。最后,在前述研究基础上,在体积为84m3的封闭试验室,将不同放电极性的针阵列对板电晕放电应用于实际空气净化中,放电反应器出口加设MnO2催化剂,研究降低放电产生有害副产物NO2和O3的效果,并通过催化剂分析,研究作用规律。最终获知满足《室内空气质量标准》(GB/T18883—2002)中NO2和O3浓度标准值的设计依据和运行条件,为室内空气净化的实际应用提供技术支持。更多还原

【Abstract】 Indoor air pollutants are characterized by their mutil-components, long period, low concentrations, and etc. Most pollutants can be effectively and rapidly removed by plasma air cleaning. Although corona discharge is adopted as a main plasma technology in indoor air cleaning, some harmful byproducts such as ozone and NOx are generated, and the corresponding secondary pollution is formed. Based on the laboratory earlier work, this thesis analyzes the properties in ionization region of multi-needle-to plate corona discharge systematically, and well studies the optimization of Excited state OH radical yield in the corona discharge by OES, which will provide design principles for needle matrix to plate DC corona discharge as the core technology of indoor air cleaning device. Taking the removal of harmful byproducts generated by corona discharge as the research goal, the generation of NO2 and O3 in corona discharge as well as their decomposition by MnO2 is studied experimentally. The relative roles of generation and removal of the byproducts are abtained by bench-scale experiements in a closed chamber and application tests. Meanwhile, the design principles and running parameters of the air cleaning device have been determined.Firstly, according to the measured experimenatal results of multi-needle-to-plate corona discharge by OES, the statistics, fitting and theoretical analyses are carried out. The isophote equations of N2 second positive band intensity (ISPB) are obtained. The distribution of ISPB and the variation of micro electrical parameters including ISPB×S, the average speed of electrons and current density in ionization region have been known. The micro physical properties in ionization and drift regions of multi-needle-to-plate positive-negative corona discharge are analysed systematically.Secondly, taking excited state OH radical as study object, the influences of discharge parameters including discharge power, electrode gap and relative humidity on OH generation in the corona discharge by OES are well studied. Under stable discharge condition, the optimized running parameters of excited OH yield have been abtained, and the relative roles between macro parameters and OH radical have been determined.In this thesis, in order to make the technology of needle matrix to plate corona discharge suitable for indoor air cleaning, safety problem caused by harmful byproducts generated in corona discharge is considered in detail. The relative roles of NO2 generated by the corona discharge are studied, especially on the influences of discharge power, discharge polarity, electrode gap and relative humidity on NO2 generation. Some principles of the parameter design as well as of qualitative running conditions have been obtained. On this basis, removal experiments of NO2 with catalyst containing MnO2 as active ingredients and SiO2-active Carbon as vector have been conducted. The relationship between MnO2 content and NO2 removal efficiency is studied under different discharge conditions such as discharge power P, relative humidity RH, discharge polarity, and etc. The method of effective removal of NO2 by MnO2 and relative running roles have been obtained.The generation of O3 and its removal with catalyst in needle matrix to plate corona discharge are also studied. The generation roles of O3 have been summarized by observing concentration variation of O3 in a closed chamber. Removal experiments of O3 with catalyst containing MnO2 as active ingredients and SiO2-active Carbon as vector have been conducted. The relationship between MnO2 content and O3 removal efficiency is studied under different discharge conditions including discharge power P and discharge polarity. The roles of O3 removal by MnO2 catalyst have been obtained.Finally, on the basis of the above work, the application tests of the noval air cleaning device with needle matrix to plate corona discharge have been conducted under different discharge polarities in a closed room of 84m3. MnO2 catalyst is set on the exit of the discharge reactor to study the removal effects of harmful byproducts of NO2 and O3 generated by the discharge. Meanwhile, the catalyst functional pattern is also studied by catalyst analysis. In the end, it has been known that the values of concentrations of NO2 and O3 generated by the corona discharge satisfy the demand of Standard of Indoor Air Quality(GB/T18883-2002). Hence, this work has provided powerful technology support for practical application of indoor air cleaning.更多还原