Experimental study on the parameter optimization and application of a packed-bed dielectric barrier discharge reactor in diesel particulate filter regeneration

To compensate for the shortcomings of the thermal and catalytic regeneration of the diesel particulate filter (DPF), a self-designed packed-bed dielectric barrier discharge (DBD) reactor for DPF regeneration was developed. The DBD reactor with the main active substance of nonthermal plasma (NTP) as the target parameter was optimized by adjusting the feed gas, packing particles (material or size), and cooling water temperature. Moreover, a set of optimal working parameters (gas source, O₂; packing particles, 1.2–1.4 mm ZrO₂; and cooling water temperature, 20 °C) was selected to evaluate the effect of different O3 concentrations on DPF regeneration. The research results showed that selecting packing particles with high dielectric constant and large particles, as well as reducing the cooling water temperature, with oxygen as the feed gas, contributed to an increase in O₃ concentration. During DPF regeneration, the following changes were observed: the power of the NTP reactor decreased to lower than 100 W, the O₃ concentration increased from 15 g m⁻³ to 45 g m⁻³, the CO and CO₂ volume fractions of the particulate matter decomposition products increased, and the peak regeneration temperature increased to 173.4 °C. The peak temperature arrival time was 60 min earlier, indicating that the regeneration rate of DPF increased with the increase in O3 concentration. However, the O₃ utilization rate (the amount of carbon deposit removed per unit volume O₃) initially increased and then decreased; when the O3 concentration was set to 25 g m⁻³, the highest O₃ utilization rate was reached. The packed-bed DBD technology contributed to the increase in the concentration of NTP active substances and the regeneration efficiency of DPF. It provides a theoretical and experimental basis for high-efficiency regeneration of DPF at low temperatures (<200 °C).