DEVELOPMENT OF A FLUOROCARBON DECOMPOSITION SYSTEM BY A FUNCTIONAL CERAMIC REACTOR WITH HIGH FREQUENCY SURFACE DISCHAGE

本研究的目的是建立环境空气控制系统，即通过在圆柱形反应器的内壁上使用高频表面放电的氧化铝基陶瓷反应器来分解环境空气中的稀释气态有机化合物的系统。表面放电产生的非平衡低温等离子体对许多挥发性化合物如CFC_（22）、CFC_（113）和其它卤代有机化合物（三氯乙烯、113-三氯乙烷、12-二氯乙烷、二氯甲烷）的分解非常有效。在任何情况下，该装置都具有非常高的分解性能，空气中90%以上的稀释污染物被去除。空气中的其他丙酮也被表面放电等离子体分解为常见的污染VOC，但丙酮很难被表面放电等离子体分解。发现醇（异丙醇）被放电氧化，并且一部分被转化为丙酮。通过GCMS（气相色谱质谱仪）分析，当分解一半（~ 50%分解率）时观察到中间体卤代化合物和氯代物。然而，在95%或更高的高分解率下，中间产物被分解，残留气体为氯代氢和二氧化碳。尚未观察到通过空气放电产生NOx。紫外线也被发现是有效的分解三氯乙烯。

The aim of this research which was continued for three years is to establish the environmental air control system, that is, the decomposition system of diluted gaseous organic compounds in environmental air by using a alumina-based ceramic reactor with high frequency surface discharge on the inner wall of a cylindrical reactor. The non-equilibrium low temperature plasma prosuced by the surface discharge is found to be very effective to decompose many voltile compounds, such as CFC22 (chloro-difluorohydromethane : CHClF_2), CFC113 (trichlorotrifluoroethane : CF_2ClCFCl_2) and other halogenated organic compounds (trichloroethylene, 113-truchloroethane, 12-dichloroethane, dichloromethane). Inevery case, very high decomposition performance by the device was very well and more than 90% of dilute contaminants in air was removed. Other acetone in air was also decomposed by the surface discharge plasma as normal contaminated VOC.Acetone is found to be very difficult to be destroyed by the discharge. Alcohol (isopropylalcohol) is found to be oxidized by the discharge and some part is changed to acetone. By GCMS (Gas-Chromatograph Mass Spectrometer) analysis, the intermediate halogenated compounds and phosgen are observed when the decomposition is half (-50% decomposition rate). However, at the high decomposition rate of 95% or more, the intermediate products are decomposed and residual gasses are chlorohydrogen and carbon-dioxide. Production of NOx by the air discharge is not yet observed. UV is also found to be effective to decompose trichloroethylene.