(545f) Effect of Power Frequency on Various Organic Compounds(VOCs) Decomposition Using Nonthermal Plasma Reactor Combined with Ceramic Filter

Recently, volatile Organic Compounds(VOCs) emissions have been controlled in various countries in the world. There are two major methods of VOCs processing methods such as incineration and adsorption. These methods are suitable for VOCs with high concentration levels and flow late, however, these are not suitable for medium- and small-scale emission sources. Therefore, the nonthermal plasma decomposition method has been drawing more attention these days as an alternative approach because of its advantages over conventional methods. In our previous work, we developed a new type electrode system for gas treatment in which nonthermal plasma and a ceramic filter were integrated and applied it for VOCs treatment. Configuration of the reactor is as follows; a copper wire electrode is wound in a coil form on the surface of a tubular porous ceramic filter as a discharge electrode. Another copper rod electrode which is insulated by a quartz tube is inserted inside the tube and is used as a counter electrode. The ceramic tube is made of alumina.
　In this study, in order to investigate the effect of both power frequency and chemical structure of VOC on the decomposition efficiency, discharge decomposition experiment of various VOCs was carried out using our nonthermal plasma reactor. In the experiment, trichloroethylene (TCE), n-hexane, benzene, n-pentane, 1-hexene, 1-clorohexane were used as VOCs to be decomposed, and the power supply frequencies were 0.5, 1, 3, and 5 kHz to perform discharge decomposition. As a result, in the case of 1-hexene and TCE, very high decomposition efficiency was shown, and at the same time, the decomposition efficiency was significantly influenced by the power frequency. On the other hand, the decompositions of 1-clorohexane, n-hexane, n-pentane and benzene were influenced by the power frequency slightly, and the decomposition efficiency was remarkably lower than the case of 1-hexane and TCE. Furthermore, when the decomposition efficiency of n-hexane was compared to 1-clorohexane, which has almost the same structure as n-hexane and just replacing one hydrogen to chlorine, the efficiency in 1-clorohexane was higher at any frequency. In addition, when the decomposition efficiency was compared between n-hexane and n-pentane, no significant difference was observed. It indicates that only one carbon number difference does not affect discharge decomposition largely in the range of this study.