低温等离子催化降解甲苯类废气工艺研究毕业论文
2022-01-14 09:01
论文总字数：18889字
摘 要
随着我国工业化进程的不断加快，环境污染也越来越严重，尤其是挥发性有机物VOCs（例如：甲苯类、醇类、醚类等）排放量日益增大，已经严重影响着地球环境和人的身体健康。利用低温等离子体处理VOCs具有运行成本低、无二次污染、操控方便等优点，已成为有机废气处理是主要技术之一。
本论文采用低温等离子体催化技术，以甲苯废气为研究对象，研究制备了ZIF-8和TiO2@ZIF-8催化剂，同时探究不同影响因素（催化剂、进气浓度、能量密度、湿度）对甲苯去除效率的影响。具体如下：
1、制备了ZIF-8和TiO2@ZIF-8两种催化剂，并进行XRD、BET、SEM和TEM表征，结果表明：所制备的ZIF-8和TiO2@ZIF-8催化剂与目标结构一致，两种催化剂比表面积分别为1360.3824m2/g、931.0245m2/g，晶体大小分布均匀，结晶度高。
2、无催化剂条件下，研究了不同进气浓度、不同能量密度、不同湿度等因素条件下，低温等离子对甲苯的去除效率影响，通过响应面分析表明：在能量密度50J/L、进气浓度1000mg/m3、相对湿度20%RH的条件下，甲苯的转化率最大达49.98%。
3、在低温等离子协同催化剂的条件下，重点研究了在两种催化剂投加量为0.1g时，对甲苯的去除效率影响，结果表明：在能量密度为70J/L、进气浓度为1000mg/m3、相对湿度为20%RH的条件下，添加ZIF-8和TiO2@ZIF-8催化剂，甲苯的转化率最高分别可达78.19%和99.05%，比未加催化剂的甲苯去除效率高将近一倍，TiO2@ZIF-8性能明显优于ZIF-8。
4、稳定性实验发现，经过32h，催化剂的性能仅衰减了16%，具有良好的催化活性。
关键词：VOCs 低温等离子体 甲苯 催化剂
Study on catalytic degradation of toluene waste gas by Non-thermal plasma
Abstract
With the development of China's economy, environmental problem is becoming more and more severe. Especially, the emission of volatile organic compounds (VOCs) is increasing day by day, which has seriously affected the earth environment and human health. Non-thermal plasma has the advantages of low operating cost, no secondary pollution and easy to control, and has become one of the main technologies of organic waste gas treatment.
In this paper, Non-thermal plasma catalysis technology was adopted to prepare ZIF-8 and TiO2@ZIF-8 catalysts by taking toluene waste gas as the research object. Meanwhile, the influences of different influencing factors (catalyst, inlet concentration, energy density, humidity) on toluene removal efficiency were explored. Specific as follows:
1. ZIF-8 and TiO2@ZIF-8 were characterized by XRD, BET, SEM and TEM. The results showed that the prepared ZIF-8 and TiO2@ZIF-8 catalysts were consistent with the target structure. ZIF-8 and TiO2@ZIF-8’s specific surface areas were 1360.3824m2/g and 931.0245m2/g, with uniform crystal size distribution and high crystallinity.
2. In the absence of catalyst, the effects of Non-thermal plasma on toluene removal efficiency were studied under different the conditions of different inlet concentrations, energy densities and humidity. It was showed that the maximum conversion rate of toluene reached 49.98% which was tested by Design Expert,under the conditions that energy density was 50J/L and inlet concentration was 1000mg/m3.meanwhile ,relative humidity was 20%RH.
3. Under the condition of Non-thermal plasma combined with catalysts, mainly studied on two kinds of catalysts dosing quantity was 0.1g, the impact on removal efficiency of toluene, the results show that the energy density of 50J/L, inlet concentration of 1000mg/m3, relative humidity was 20%RH, add ZIF-8 and TiO2@ZIF-8, toluene degradation rate was highest that can amount to 78.19% and 99.05% respectively, than that without catalyst of toluene removal efficiency nearly doubled, TiO2@ZIF-8’s performance is superior to ZIF-8.
Key Words: VOCs; Non-thermal plasma; toluene; catalyst
目 录
摘要 I
Abstract II
目 录 IV
第一章 绪论 1
1.1 研究背景 1
1.2 VOCs的控制技术 1
1.3 低温等离子体原理 2
1.3.1 电晕放电 3
1.3.2 介质阻挡放电（DBD） 3
1.4 介质阻挡放电（DBD）技术研究进展 4
1.5 本课题的研究内容 5
第二章 实验仪器与方法 6
2.1 药剂及仪器 6
2.2 实验装置及方法 7
2.2.1实验装置 7
2.2.2实验装置介绍 7
2.3 放电参数分析 9
2.3.1 放电功率 9
2.3.2 能量密度 10
2.4 气体组分分析 10
2.5 甲苯转化率 10
第三章 催化剂的制备与表征 11
3.1 ZIF-8介绍 11
3.2 催化剂的制备 11
3.3 催化剂的表征分析 11
3.3.1 XRD 12
3.3.2 BET 12
3.3.3 SEM 13
3.3.4 TEM 13
3.4 本章小结 14
第四章 低温等离子体催化降解甲苯性能 15
4.1 不同进气浓度对甲苯降解性能的影响 15
4.2 不同能量密度对甲苯降解性能的影响 16
4.3 不同湿度对甲苯降解性能的影响 17
4.4 结合响应面软件分析 17
4.5 ZIF-8与TiO2@ZIF-8催化剂协同条件下甲苯的降解性能研究 18
4.6 稳定性测试 20
4.7本章小结 20
第五章 结论与展望 22
5.1 结论 22
5.2 展望 22
参考文献 23
致谢 26
第一章 绪论
1.1 研究背景
随着我国工业产业现代化进程的加快，生态环境也遭受着不同程度地破坏，大气环境污染日益严重，空气质量日益下降，雾霾成为了我们生活中很头疼的话题。大气污染物排放量的增多是空气质量下降的主要原因，挥发性有机物（VOCs）在大气光化学过程中起着非常重要的作用，影响着大气的氧化性、二次气溶胶的形成和大气辐射等，对全球气候环境有着重要影响。
挥发性有机物是一类有机化合物的总称，在常温下它们的蒸发速率大，易挥发，是造成空气污染的主要原因[1]。VOCs的人为排放大量来自交通运输、石化行业以及有机溶剂使用过程，比如常见的石油炼油厂和燃料燃烧等[2]。典型VOCs包括苯类、酯类、醇类、酮类和醛类等[3]。VOCs还具有毒性、致畸致癌性[4]，严重危害人体健康。
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