Performances of Nanosecond Pulsed Discharge

Abstract

The conventional methods such as selective catalytic reduction method, electron beam method and lime--gypsum method could not treat exhaust gases completely. In addition, the energy efficiency and the cost of the conventional ways are still unfavourable. In recent years, the pollution control techniques using electric discharge plasmas which attract attention as the low cost and high energy efficient exhaust gas treatment methods, have been widely studied. In our laboratory, pulsed streamer discharge plasmas which are one of the non-thermal plasmas have been used to treat exhaust gases. Since a pulse width of applied voltage has a strong influence on the energy efficiency of the removal of pollutants, the development of a short pulse generator is of paramount importance for practical applications. In this work, nanosecond pulse generator which can output the 5 ns pulsed voltage is developed. In addition, the exhaust gas treatment and the ozone production by nanosecond pulse generator were demonstrated.

Nanosecond pulsed streamer discharges: II. Physics, discharge characterization and plasma processing

“…The difficulty with 5 ns discharge is working at increased ozone concentrations. Figure 29 shows the dependence of O 3 yield on O 3 concentration for different pulse discharge durations [89].…”

Plasma and catalyst for the oxidation of NOx

“…The theoretical efficiencies for the production of oxygen radicals and ozone by barrier discharges ignited by sinusoidal or microsecond range pulsed voltages remain in the range of 200-250 g kWh −1 in pure oxygen [67,93] and 100-110 g kWh −1 in dry air. The efficiency may increase up to 500 g kWh −1 and 200 g kWh −1 for pure oxygen and air with the use of nanosecond pulsed discharges [35]. The stoichiometric amount of ozone which is required for the oxidation of NO to NO 2 and N 2 O 5 are respectively 1 and 1.5 times the concentration of inlet NO.…”

“…The use of plasma additionally allows the oxidation of NO 2 to N 2 O 5 which is beneficial for absorption based methods. Studies carried out by different research groups have shown that it is possible to oxidize all NO to NO 2 when inlet NO concentration is up to of 200-330 ppm depending on experimental conditions [30][31][32][33][34][35][36][37][38][39][40][41][42][43]. The input energy (SIE) required to remove all NO at 200 ppm inlet NO concentration varied from 20 to 200 J l −1 depending on gas composition and reactor temperature [33,36,39,42,43].…”

Process Performances of 2 ns Pulsed Discharge Plasma

“…[14][15][16] It is already reported that a nanosecond pulsed generator that can output 5 ns pulsed voltage was developed for use in exhaust gas treatment and ozone production. [17][18][19][20][21][22][23] In refs. 17-23, it was indicated that the 5 ns pulsed discharge has great advantage in terms of energy efficiency for NO removal and ozone generation over conventional discharge methods.…”