Continuous Regeneration of Ceramics Particulate Filter in Stationary Diesel Engine Using Nonthermal Plasma-Induced Ozone Injection

The regulation for the diesel engine emission becomes stringent every year, and it is difficult to meet the requirement only by the combustion improvement techniques in the near future. More effective post-processing technology is desired especially on particulate matter (PM), such as carbon soots. Although the use of ceramic diesel particulate filter (DPF) is now a leading technology for PM removal, the problem exists on the soot removal or regeneration at low temperature, especially at the cold start. In the present study, a pilot scale experiments on nonthermal plasma regeneration of diesel particulate filter in stationary diesel engine generator is carried out using the low temperature atmospheric pressure nonthermal plasma induced ozone injection. In the method, the NO₂ and ozone induced by the plasma reactor is used to burn carbon soots deposited on DPF. Regeneration experiment is carried out with a small diesel engine and a surface discharge type plasma ozonizer. The amount of injected ozone required for the regeneration is determined under various operation conditions of the engine, It is confirmed that the pressure difference decreased only when the plasma is turned on and the regeneration of DPF is realized approximately at 250degC. The required plasma energy is only 0.25% of the generated power of the engine.