A gliding discharge applied to H2S destruction

The destruction of foul smelling gases is an important subject involving a number of industrial applications. Increased interest is being devoted to technologies based on the properties of cold plasmas, which are the subject of a large body of research. Among all possible techniques, the sliding discharge is one of the simplest to utilize. We present a study of the destruction of H2S diluted in air by this type of discharge. We first describe the electric power supply, its characteristics and the design of the reactor. The properties of the discharge and its changes are then described using measurements of voltage, current, and different characteristic parameters: temperatures, velocities, and length of the discharge. After describing the instrumentation used for chemical diagnoses, the main experimental results are presented. They show the changes in the conversion rate as a function of the flow rate of the gas to treat and the dimensions of the reaction chamber, enabling a model of discharge changes to be defined. The model defines a zone of transformation corresponding to a volume swept by the plasma. It was thus possible to determine how destruction efficiency is affected by construction parameters, reactor dimensions, voltage, and flow rates. The energy cost per molecule destroyed is relatively high because the pollutant is diluted. With several improvements, the possibility of processing high flow rates with a simplified implementation could enable immediate industrial application to be envisaged. (C) 1998 American Institute of Physics.