低温等离子体降解VOCs的DBD反应器优化探索和产物分析

发布时间：2018-03-09 03:26

本文选题：介质阻挡放电　切入点：反应产物　出处：《东华大学》2017年硕士论文　论文类型：学位论文

【摘要】：挥发性有机化合物(VOCs)对环境造成的危害是继氮氧化物、硫化物之后的又一主要污染源。VOCs易挥发性及有毒性,给人类居住环境造成不可估量的伤害。近些年来,随着处理技术的发展,低温等离子体作为一种适用于各种VOCs的高效率降解技术,得到广泛的重视和研究。本文为了探索优化低温离子体降解VOCs技术的方向和途径,通过同轴圆柱和平板两种类型放电腔对DBD等离子体降解甲苯进行研究,对比了不同放电结构下的降解效率,定性和定量地分析了中间副产物,并对降解途径进行了分析。研究结果表明:(1)对比研究了圆柱和平板放电腔在相同能量密度及相同放电体积下,DBD放电装置对甲苯的降解效果。结果显示圆柱放电腔具有更好的降解效率、碳平衡和碳选择性及更好的能量效率。(2)利用GC和GC-MS对两种结构下的反应产物成份进行测量和分析,发现了两种结构下产物出现顺序的异同及其与放电功率间的联系,并结合简单的静态电场计算和甲苯的键能结构,得出DBD降解产物与等离子体电子能量相关联。随着能量密度的增加两种放电腔形成的副产物逐渐增多,最终产物类型一致,都是甲酸、乙酸、丙酮、苯、苯甲醛和硝酸甲酯。同时,由于化学键能及高能电子的影响,这些产物产生顺序为:苯甲醛→苯→甲酸、乙酸和硝酸甲酯→丙酮,由于生产苯甲醛、苯、甲酸、硝酸甲酯和乙酸所需的能量相差不大,实验测得为同时产生。(3)研究了同轴圆柱放电腔结构尺寸对甲苯降解效率的影响。研究介质厚度和尺寸大小对降解效率的影响,结果显示在同电压下,薄的介质有利于甲苯的降解效率,同时中型尺寸的圆柱放电腔具有相对较好的降解效率和能量效率。(4)尝试利用氧化金属来提高DBD等离子体降解VOCs效率。选择Zr O_2和Mg O涂层添加于内平板放电腔下,研究其对甲苯降解和产物的影响。结果显示涂层能有效提高甲苯的降解效率和能量效率,Zr O_2涂层下最大能量效率提高了79%,Mg O涂层的最大能量效率提高了33%。结果还显示Zr O_2涂层在降解效率和能量效率上明显好于Mg O涂层,但O_3浓度较高。而Mg O涂层具有更好的碳平衡和碳选择性,同时能降低O_3产生。
[Abstract]:VOCs is another major pollution source after nitrogen oxides and sulfides. VOCs are volatile and toxic, causing incalculable harm to human living environment in recent years. With the development of treatment technology, low temperature plasma, as a kind of high efficiency degradation technology suitable for various kinds of VOCs, has been widely paid attention to and studied. In order to explore the direction and way of optimizing low temperature ionomer degradation VOCs technology, The degradation of toluene by DBD plasma was studied by two types of discharge cavities, coaxial cylinder and flat plate. The degradation efficiency of toluene in different discharge structures was compared, and the intermediate by-products were analyzed qualitatively and quantitatively. The results show that the degradation of toluene in cylindrical and flat discharge cavities under the same energy density and same discharge volume is comparatively studied. With better degradation efficiency, Carbon balance and carbon selectivity and better energy efficiency. (2) using GC and GC-MS to measure and analyze the composition of the reaction products under the two structures, the similarities and differences of the order of occurrence of the products under the two structures and their relationship with the discharge power are found. Combined with the simple static electric field calculation and the bond energy structure of toluene, it is concluded that the degradation products of DBD are related to the electron energy of the plasma. With the increase of the energy density, the by-products formed by the two discharge cavities increase gradually, and the final products are of the same type. They are formic acid, acetic acid, acetone, benzene, benzaldehyde and methyl nitrate. At the same time, due to the influence of chemical bond energy and high energy electrons, these products are produced in the following order: benzaldehyde. 鈫払enzene. 鈫扚ormic acid, acetic acid and methyl nitrate. 鈫扐cetone, because the energy required to produce benzaldehyde, benzene, formic acid, methyl nitrate and acetic acid is not much different, The effect of the structure size of the coaxial cylindrical discharge cavity on the degradation efficiency of toluene was studied. The effect of the thickness and size of the medium on the degradation efficiency was studied. Thin medium is beneficial to the degradation efficiency of toluene. At the same time, the medium size cylindrical discharge cavity has relatively good degradation efficiency and energy efficiency. 4) the oxidation metal is used to improve the degradation efficiency of VOCs by DBD plasma. The ZrSnO2 and MgO coatings are added under the inner plate discharge cavity. The results show that the coating can effectively improve the degradation efficiency and energy efficiency of toluene. The maximum energy efficiency under Zr O 2 coating increases the maximum energy efficiency of 79mg O coating by 33%. The results show that the degradation efficiency and energy efficiency of ZR / SnO2 coating are better than that of MgO coating. Mg-O coating has better carbon balance and carbon selectivity, and can reduce the production of O _ (3) at the same time.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ052;X701

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