VOCs向PM2.5转化机理研究

发布时间：2018-03-27 22:29

本文选题：烟雾箱　切入点：臭氧　出处：《河北科技大学》2015年硕士论文

【摘要】：目前中国大气污染日益严峻,引起社会各界广泛关注。大气污染物来源非常广泛,其中人为产生的挥发性有机物是当前主要的大气污染物之一,在复杂多变的大气环境下挥发性有机物的各种转变对环境以及人类健康产生了极大的影响。自制了小型烟雾箱系统用于研究大气中挥发性有机物向细颗粒物(PM2.5)转化的机理。烟雾箱主体材料采用全氟乙烯丙烯共聚物(Fluorinated ethylene propylene FEP)膜制造,FEP膜本身不参与反应并且能够最大限度透过紫外线。反应器的框架采用有机玻璃激光切割加工,工艺成熟便于加工和扩展。采用外部支撑的方式,利用人气压辅助排气的手段省去了抽真空的环节,简化了实验系统。自制的烟雾箱体积300L,比表面积9.67m-1,常温下臭氧的半衰期为12h,臭氧的壁损失系数0.0618h-1。对烟雾箱进行了表征并且针对臭氧和紫外线对反应物反应速率的影响进行了研究。并将实验数据与中心化学机理(MCMv3.1)中丙酮的子机理演化结果进行了对比分析。对比其他小型烟雾箱属于正常水平。经过多次实验,自制烟雾箱表现良好,能够胜任大气光化学实验的要求。针对丙酮进行了多因素的对比试验,测量了本烟雾箱背景条件下丙酮的标准曲线,线性相关系数达到0.99,满足实验要求。测定了丙酮的壁损失系数,常温常压无光照情况下为0.00144 h-1。研究了紫外线和臭氧对丙酮分解反应影响的不同,对比发现紫外线对丙酮的分解起到了关键性的影响。并且结合MCMv3.1机理,利用FACS IMILE软件对丙酮的变化情况进行了模拟,模拟结果与实际实验有较大偏差,这是由于初始条件和反应历程的双重影响造成的,表明不同的地区需要做针对性的模拟实验来探讨和验证挥发性有机物的转变过程。
[Abstract]:At present, air pollution in China is becoming increasingly serious, causing widespread concern from all walks of life. Air pollutants come from a wide range of sources, among which man-made volatile organic compounds are one of the main atmospheric pollutants at present. The changes of volatile organic compounds (VOCs) in complex and changeable atmospheric environments have a great impact on the environment and human health. A small smoke Box system has been developed to study the transition of VOC to PM2.5) in the atmosphere. The main material of the smog box is made of perfluoroethylene propylene copolymer (perfluorinated ethylene propylene FEPPE) film. The FEP film itself is not involved in the reaction and can penetrate ultraviolet ray to the maximum extent. The reactor frame is cut by plexiglass laser. The process is mature and easy to process and expand. By means of external support, the air pressure is used to assist the exhaust to save the vacuum pumping. The experimental system was simplified. The volume of the self-made smoke box was 300L, the specific surface area was 9.67m ~ (-1), the half-life of ozone was 12h at room temperature, and the wall loss coefficient of ozone was 0.0618h-1.The smoke box was characterized and the reaction rate of ozone and UV to reactants was analyzed. The experimental data were compared with the results of the evolution of acetone in the central chemical mechanism (MCMv3.1). The self-made smoke box has good performance and can meet the requirements of atmospheric photochemical experiments. A multi-factor comparative test was carried out for acetone, and the standard curve of acetone was measured under the background condition of the smoke box. The linear correlation coefficient reached 0.99. the wall loss coefficient of acetone was determined, which was 0.00144 h-1.The effects of UV and ozone on the decomposition of acetone were studied. It is found that UV rays play a key role in the decomposition of acetone. Combined with the mechanism of MCMv3.1, the variation of acetone is simulated by FACS IMILE software. The simulation results are quite different from the actual experiments. This is caused by the dual influence of initial conditions and reaction process, which indicates that different regions need to do targeted simulation experiments to study and verify the transition process of volatile organic compounds (VOCs).
【学位授予单位】：河北科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X51

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