Investigation of a pulse circuit design and pulse condition for the high energy efficiency on water treatment using pulsed power discharge in a water droplet spray

The pulsed power is one of technologies to solve the problem of water pollution. Since the pulsed streamer discharge can generate not only ozone but also OH radical, ultraviolet rays and shockwaves, it is expected to have high efficiency for the treatment and decompose the pollutants that cannot be easily decomposed by even ozone oxidation. Therefore, we have been studying the method that uses the pulsed streamer discharge generated in air with water droplets as the method with highest energy efficiency in the water treatment method by the discharge. In this study, in order to get higher efficiency in this method, we have investigated a pulse circuit design and pulse conditions in which the energy is transferred efficiently from a pulsed power generator to the discharge and the treatment efficiency is higher. The output power from the pulsed power generator is limited by switching time of the high voltage FET switches in it. In the experiment, optimum output time of pulsed voltage and resistance value in the pulsed power generator for higher energy efficiency was investigated. The results show that high resistance value and the output time of pulsed voltage of 100ns give highest efficiency for the generator and the treatment, because the discharging power increased at high resistance value and until the output time of 100 ns. The maximum energy transfer ratio is approximately 40%.