NO/sub x/ removal from engine exhaust gas using multipoints DBD and pulse streamer discharges with SOS pulse generator

Abstract

NO/sub x/ removal from a diesel engine exhaust and simulated gases was carried out using two different nonthermal plasma reactors. One is multipoints dielectric barrier discharge (DBD) reactor, the other is pulse streamer discharge (PSD) reactor. In the former reactor, the 2 mm thickness Pyrex glass plate is used as the dielectric barrier. The DBD reactor is driven by IGBT pulse modulator which can supply the 10 kV pulse voltage to the reactor with repetition rate of 2.5 kpps. The co-axial cylinder type discharge chamber is used as the PSD reactor which is driven by the pulse power generator with semiconductor opening switches (SOS). The SOS pulse generator can supply both polarity of 30 kV pulse with 300 pps repetition rate. The DBD reactor energy cost for NO removal from simulated gas (N/sub 2/:O/sub 2/=9:1, initial NO concentration = 200 ppm) is obtained to 12 g/kWh at 65% removal in 5 l/min. gas flow rate. The energy cost of the PSD reactor is almost 12 g/kWh at 25% NO removal efficiency. The DBD reactor was applied to 20 kVA diesel engine generator exhaust gas treatment. The contained NO/sub x/ (NO+NO/sub 2/) is abated from 70 to 40 ppm at no-load to the generator, and from 340 to 300 ppm. at 50 A load. The energy cost for the NO/sub x/ removal is obtained to 32 g/kWh.