NONEQUILIBRIUM VOLUME PLASMA CHEMICAL-PROCESSING

A review is presented of plasma chemical processes occurring in the volume part of electrical nonequilibrium discharges. The role of energetic electrons as initiators of chemical reactions in a cold background gas is discussed. Different discharge types (glow, corona, silent, RF, and microwave discharges) are investigated with respect to their suitability for plasma chemical processing. Emphasis is placed on the requirements of initiating and maintaining the discharge and, at the same time, optimizing plasma parameters for the desired chemical process. Using large-scale industrial ozone production as an example, the detailed process of discharge optimization is described. Other applications of volume plasma processing include other plasma chemical syntheses as well as decomposition processes such as flue gas treatment and hazardous waste disposal. If large gas volumes have to be handled, mainly the silent discharge and possibly also corona discharges have a chance of industrial acceptance as far as nonequilibrium plasma processing is concerned.