沿面—填充床双极性纳秒脉冲放电等离子体协同催化处理苯研究

发布时间：2018-04-20 02:35

本文选题：复合反应器 + 双极性脉冲放电　；参考：《大连理工大学》2016年硕士论文

【摘要】：挥发性有机污染物(VOCs)能够对环境产生不利的影响,同时对人类健康还会造成不可逆的伤害。相比于传统的VOCs处理方法,低温等离子体法具有处理效率高、选择性好等优点。针对单独沿面、填充床等离子体反应器能量效率低、矿化不彻底等问题,本文采用双极性脉冲电源激励沿面-填充床复合式(Series Surface/Packed-bed Discharge, SSPBD)等离子体反应器处理VOCs.该反应器同时具有沿面和填充床反应器的结构,实现了对污染物的顺序处理,从而提高了对污染物的降解效率。由于单独使用等离子体法处理VOCs存在矿化效率不高、产生有害副产物等不足,因此本实验引入催化剂,将等离子体与催化过程相结合,同时还可以进一步提高污染物的降解效率。本文主要考查了SSPBD反应器相比于单独沿面(Surface Discharge, SD)、单独填充床(Packed-bed Discharge, PBD)反应器在处理污染物方面的优势、实验系统的结构及电气参数的优化及结合催化剂处理污染物等方面的问题。主要工作与结果如下：(1)研究了SSPBD、SD及PBD三种反应器和SSPBD反应器内不同放电区域对污染物的处理效果。结果表明：当反应器放电功率相同时(10.33 W), SSPBD反应器比SD、PBD反应器对苯的降解效率分别高了29%和11%,CO2的选择性分别高了17%和9%,产生03的浓度分别高了3.1和10mg/ L。另外,通过对苯的降解效率、CO2的选择性、产生03和N02的浓度及原子发射光谱等方面的对比,表明在SSPBD反应器内,填充床放电区域在活性物质产生及污染物降解方面起到了主要作用；(2)优化了实验系统的结构参数及电气参数,结果表明：当反应器外部有机玻璃管内径为338 mm,内部石英管外径为23.0 mm、内径为16.8 mm时,可以实现两部分放电区域平均分配反应器注入能量。当放电电极螺距为12 mm,线圈直径为1.2 mm,填充玻璃珠粒径为2 mm时,对污染物的降解效率有所提高。50 Hz和1 nF作为本实验的最佳脉冲重复频率及成形电容值；(3)本实验对比了MnO2-TiO2/zeolite、TiO2/zeolite和MnO2/zeolite催化剂在结合SSPBD反应器时的催化效果。结果表明,MnO2-TiO2/zeolite催化剂的催化活性要高于TiO2/zeolite、MnO2/zeolite催化剂。当反应器的注入功率为10.33 W时,MnO2-TiO2/zeolite催化剂对苯的降解效率、C02的选择性、03的分解率及产生N02的浓度比单独等离子体放电反应器分别提高了23%、19%、72%及48%。当催化剂被放置在末端位置时对污染物的处理效果最高,空气湿度为25%时,存在最优的湿度条件。
[Abstract]:Volatile organic pollutants (VOCs) can not only have adverse effects on the environment, but also cause irreversible harm to human health. Compared with the traditional VOCs treatment method, the low temperature plasma method has the advantages of high treatment efficiency and good selectivity. In order to solve the problems such as low energy efficiency and incomplete mineralization in a packed bed plasma reactor, a hybrid series Surface/Packed-bed charge (SSPBDD) plasma reactor with a bipolar pulse power source is used to treat VOCs. The reactor has the structure of both surface and packed bed reactor, which realizes the sequential treatment of pollutants, thus improving the degradation efficiency of pollutants. Because the treatment of VOCs by plasma alone has some disadvantages, such as low mineralization efficiency and harmful by-products, the catalyst is introduced to combine plasma with the catalytic process. At the same time, the degradation efficiency of pollutants can be further improved. In this paper, the advantages of SSPBD reactor in treating pollutants, the optimization of experimental system structure and electrical parameters, and the treatment of pollutants with catalyst are mainly investigated in comparison with surface charge (SDD) and packed bed reactor (PBDs). The main work and results are as follows: 1) the effects of different discharge regions in SSPBDSD and PBD reactors and SSPBD reactors on the treatment of pollutants were studied. The results showed that when the discharge power was the same, the degradation efficiency of benzene in SSPBD reactor was 29% higher than that in SD-PBD reactor, and the selectivity of CO _ 2 was 17% and 9% higher than that in SD-PBD reactor, respectively, and the concentration of 03 was 3.1% higher than that of 10mg/ L. In addition, the selectivity of CO2 to benzene degradation efficiency, the concentration of 03 and N02 and atomic emission spectra were compared. The results showed that in SSPBD reactor, The discharge region of packed bed plays a major role in the production of active substances and the degradation of pollutants.) the structural and electrical parameters of the experimental system are optimized. The results show that when the inner diameter of the outer plexiglass tube is 338 mm, the outer diameter of the quartz tube is 23.0 mm and the inner diameter is 16.8 mm, the injection energy can be equally distributed between the two parts of the discharge region. When the pitch of discharge electrode is 12 mm, the diameter of coil is 1.2 mm, and the diameter of filled glass beads is 2 mm, The degradation efficiency of pollutants was improved. 50 Hz and 1 NF were used as the optimum pulse repetition frequency and the forming capacitance of the experiment. The catalytic effects of MnO2-TiO2 / zeolite / TiO2 / zeolite and MnO2/zeolite catalysts on SSPBD reactor were compared in this experiment. The results show that the catalytic activity of MNO _ 2-TiO _ 2 / zeolite catalyst is higher than that of TIO _ 2 / zeolite / MNO _ 2 / zeolite catalyst. When the injection power of the reactor is 10.33 W, the degradation efficiency of benzene over the MNO _ 2-TiO _ 2 / zeolite catalyst and the concentration of N02 in the selective nitrite of C02 are increased by 23192% and 48%, respectively, compared with the plasma discharge reactor alone. When the catalyst is placed in the terminal position, the treatment effect of pollutants is the highest, and when the air humidity is 25, there is the best humidity condition.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X701

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