Pulsed power corona discharges for air pollution control

Successful introduction of pulsed corona for industrial purposes very much depends on the reliability of high-voltage and pulsed power technology and on the efficiency of energy transfer. In addition, it is of the utmost importance that adequate electromagnetic compatibility (EMC) is achieved between the high-voltage pulse source and the surrounding equipment. Pulsed corona is generated in a pilot unit that produces narrow 50 MW pulses at 1000 pps (net average corona power 1.5 kW). The pilot unit can run continuously for use in industrial applications such as cleaning of gases (100 m³/h) containing NO or volatile organic compounds (VOCs) or fluids (e.g., waste water). Simultaneous removal of NO and ethylene to obtain clean CO₂ from the exhaust of a combustion engine was tested at an industrial site. Various chemical processes, such as removal of toluene or styrene from an airflow are tested in the laboratory. We developed a model to analyze the conversion of these pollutants. To examine the discharges in the reactor we use current, voltage, and E-field sensors as well as a fast charge-coupled device (CCD) camera. Detailed energy input measurements are compared with CCD movies to investigate the efficiency of different streamer phases. EMC techniques incorporated in the pilot unit are based on the successful concept of constructing a low transfer impedance between common mode currents induced by pulsed power and differential mode voltages in signal lines and external main lines