Collection of Diesel Exhaust Particles using Electrostatic Charging prior to DPF and Regeneration of DPF using Sliding Discharge
H. Hayashi, D. Sakiyama, K. Takashima, and A. Mizuno
Department of Environmental and Life Sciences, Toyohashi University of Technology, Japan
Abstract— Diesel particulate filter (DPF) has been established as a key technology in reducing diesel particulate emission. However, technological improvements to pressure drop, durability, and to insufficient collection efficiency for nano-particles are still required. Electrostatic precipitator (ESP) is another leading technology used in exhaust treatment, but it is currently limited to applications for stationary sources. In this paper we have proven that simultaneous use of ESP and DPF show synergetic effects of very high collection efficiency and slower increase of the pressure drop. The particle number density observed downstream of the combined system was 98% smaller compared to that of DPF alone. At the same time, it was confirmed that increase in the pressure drop across the DPF was slower by about 10% compared to that of DPF only. In addition, regeneration of DPF was also investigated using non-thermal plasma (NTP). In order to generate the plasma inside the DPF, a surface discharge was used in front and a DC electric field was applied across the DPF. In this study, the discharge plasma was used to oxidize particle matter (PM) accumulated inside the DPF. It showed around ten grams per kilowatt-hour (g/kWh) of the PM oxidation efficiency.
Keywords— Diesel exhaust aftertreatment, electrostatic precipitator, surface discharge, sliding discharge, DPF, regeneration