Experimental Research On DPF Regeneration By Non-thermal Plasma Technology Based On PBRs

Using the diesel particulate filter(DPF)can efficiently capture particulate matter(PM)in diesel exhaust,but the DPF must be regenerated in due course.Non-thermal plasma(NTP)technology is a new type of exhaust purification technology.By using the strong oxidizing property of NTP,PM can be oxidized and decomposed at a temperature far below the ignition temperature of PM to achieve the effect of removing PM.Based on NTP technology,packed bed reactors(PBRs)were designed in this paper.Discharge tests with different monitor capacitances were carried out.The influence of operating parameters changed on PBRs performance were studied.Finally,the effects of regeneration strategies on DPF regeneration were explored using PBRs.The main research contents are as follows:(1)By changing the measurement capacitance,the parameters of dielectric capacitance,gas gap capacitance and burning voltage of dielectric barrier discharge(DBD)reactor were analyzed through the applied voltage signal and Lissajous graph,and the influence of monitor capacitance on DBD reactor discharge was explored.The results indicated that the dielectric capacitance decreased with the increasing monitor capacitance.The gas gap capacitance increased with the increasing monitor capacitance.The effective electric field of the discharge gap and the reduced field of the discharge gap were negatively correlated with the monitor capacitance.Hovever,the burning voltage,power of the DBD reactor,and transferred charge also decreased with increasing monitor capacitance.(2)The self-designed PBRs as the research object,through changing operating parameters,analyzed the effect of PBRs power,material and size of packed particle,type and flow rate of feed gas,type of coolant,and temperature of cooling water on ozone generation,using ozone concentration,ozone yield and ozone production efficiency as indicators.The influence of operating parameters on PBRs performance were investigated.The results indicated that compared with air,using oxygen as feed gas can obtain higher ozone concentration and ozone yield.The flow of feed gas was negatively correlated with ozone concentration and positively correlated with ozone yield.Increasing the size and dielectric constant of packed particle would increase ozone concentration and ozone yield.Packed with ZrO2 particle,ozone concentration can reach up to112.4 g/m~3.Using water or air as coolant,the ozone production efficiency was quite different.Ozone concentration and ozone yield would gradually decrease with the increasing cooling water temperature.(3)PBRs were used to experimentally study the regeneration effect of DPF by different regeneration strategies.The effects of different ozone concentrations and different PM filtering times on DPF regeneration were investigated using oxidation products,carbon removal,axial and radial regeneration temperature as evaluation parameters.The results indicated that,with increasing ozone concentration,CO and CO2 volume fractions showed an upward trend;carbon removal and peak regeneration temperature gradually increased;and peak regeneration temperature arrival time gradually advanced.With increasing PM filtering times,CO and CO2volume fractions gradually increased;carbon removal and peak regeneration temperature also showed an upward trend;but peak regeneration temperature arrival time was gradually delayed.Along the DPF axis,peak regeneration temperature gradually increased with the backward movement of the temperature monitor point;peak regeneration temperature arrival time at the rear of DPF lagged behind that at the front of DPF.Along the DPF radial,peak regeneration temperature decreased from inside to outside;peak regeneration temperature arrival time gradually lagged behind.