Nonthermal plasma processing for controlling volatile organic compounds

Power consumption and byproducts analysis are two key issues that users must address in determining which nonthermal plasma technology is the most appropriate for certain applications. We compared the operating characteristics and power Consumption for scaled-up nonthermal plasma devices: pulsed-corona, packed-bed, silent corona, and surface discharge plasma technologies. Advantages and disadvantages of each nonthermal plasma technology are discussed. Understanding of plasma chemistry or byproducts is also essential for the development of nonthermal plasma technologies. Plasma chemical reactions of trichloroethylene (TCE) and alkyl acetates were investigated using pulsed-corona and packed-bed reactors. The effects of excited electrons, background gas, moisture, and reactor-dependent phenomena on product distribution and chemical interaction were studied. The initial step of plasma chemical decomposition of TCE can be ascribed to the electron attachment (not to active oxygen species or OH radicals), followed by homolysis and/or heterolysis reactions. Extremely high decomposition of TCE was obtained in nitrogen. Byproduct formation was significantly suppressed under aerated conditions. Alkyl acetate decomposition was affected by reactor type and alkyl chain length.