(607a) Effect of the Number of Pairs of Dielectric Barrier Discharge Reactor on Diesel Particulate Matter Removal and Pressure Drop

We have developed an uneven type of dielectric barrier discharge (DBD) reactor, which consists of uneven alumina plates and uneven stainless steel plates, for diesel particulate matter (PM) removal. The experimental system mainly comprises of a diesel engine (4-cycle, DI, 2 liter), an uneven DBD reactor, a discharge system, and a PM emission rate monitor. The pulse power supply was used to generate corona discharge in each gap between the uneven alumina plate and uneven stainless steel plate, where PM was oxidized by some active oxygen species produced by the corona discharge. The pressure drop in the DBD reactor was measured with a pressure sensor installed before the DBD reactor. The PM emission rate under conditions with or without corona discharges was measured with the PM emission rate monitor. For practical use, the energy efficiency and pressure drop are very important. In this study, we investigated the effect of the number of layers on the performance of the reactor because the increase in the number of the layers of the uneven alumina and stainless steel plates can be considered to increase the energy efficiency and decrease the pressure drop. PM removal and energy efficiency using 20 layers were 66-84% and 2.9-0.85 g/kWh, respectively, in the range of energy injection of 80-340 W. When 50 layers were used, the energy efficiency was increased to 12.4-3.6 g/kWh with PM removal of 82-93% in the range of the energy injection of 87-330 W. The increase in the number of layers from 20 to 30 or 50 increases the cross section and discharge (reaction) area of the reactor. Thus, the increase in PM removal and energy efficiency is due to the increase in the discharge area. The pressure drop was 7.8 kPa when 20 layers were used. However, the pressure drop was decreased to 5.1 or 4.1 kPa by using 30 or 50 layers because of the increase in cross section of the reactor. These results indicate that the increase in the number of layers is an effective way to improve the performance of the DBD reactor. This study was supported by the New Energy and Industrial Technology Development Organization (NEDO), Japan.