Cooperative Research on Gaseous Air Contaminants Removal by using of Discharge Plasma Processing

本项目的主要目的是利用非热等离子体技术进行气体污染物净化的基础研究和实用技术的开发。所研究的污染物是燃料燃烧排放的废气中的各种挥发性有机化合物(VOCs)和NOx。典型的挥发性有机化合物是氯氟碳(CFC-113：防止臭氧层消耗)、卤化有机化合物(三氯乙烯、四氯甲烷：致癌或其他原因)和正常的有机物质，如酒精、丙酮。非热等离子体的产生方法多种多样。它们是采用内壁形成条形电极的氧化铝陶瓷反应器或内壁接触螺旋线电极的石英管的高频表面放电，阻挡放电，或在不需要阻挡的情况下的超短脉冲放电。现在也在测试这些放电的联合效应或相互比较。在任何情况下，如果提供足够的放电能量，分解率都可以达到95%以上。VOCs的最终分解产物为二氧化碳和水。用FID-GC、GC-MS和FTIR对等离子体产生的各种副产物进行了鉴定，发现等离子体对NOx的分解强烈依赖于残余氧浓度。添加氨气或其他气体对于提高NOx的脱除是必要的。催化、添加和等离子体处理相结合的方法对降低NOx是非常有效的。

The main aim of this project is that fundamental research and development of practical technology of cleaning gaseous air contaminants by using Non-Thermal Plasma Processing. Contaminants studied are various volatile organic compounds (VOCs) and NOx in flue gas exhausted from fuel combustion. Typical VOCs are chlorofluoro-carbon (CFC-113 : controlled against ozone layr depletion), halogenated organic compounds (trichloroethylene, tetrachloromethane : cause of cansor or others) and normal organic materials such as alcohol, acetone. Non-Thermal Plasma is generated by various methods. They are high frequency surface discharge using an alumina ceramic reactor with stripe electrode formed on inner wall or a quartz tube with a spiral wire electrode contacted on the inner wall, barrier discharge, or ultra short pulse discharge where barrier is not essential. Combining effects of those discharge or mutual comparison were also tested now. In any case, very high decomposition rate more than 95% is available, if enough dischage energy is supplied. Final products of VOCs decomposition are found to carbondioxide and water. Various byproducts generated by the plasma were identified by using FID-GC,GC-MS and FTIR.It is found that NOx decomposition by the plasma is strongly dependent on the residual oxygen concentration. The addition of anmonia or others is necessary to enhance NOx removal. Combined method of catalysis, additioning and plasma processing was very effective in reducing NOx.