Study On The Influence Factors Of Non-thermal Plasma Exhaust-purification

With the further development and application of diesel engine in the field of commercial vehicles and passenger cars, relevant emissions regulations gradually follow international standards, and higher requirements will be achieved. The diesel engine discharges a larger proporation of NOx(nitrogen oxides)and PM(particulate matter), and there are a great number of exhaust control technologies directed to them. The non-thermal plasma exhaust technology introduced in this paper can adapt to the more stringent emission regulations in the future, which is able to control the NOx and PM emission in a lower range.Besides, its combination with other exhaust control technologies also becomes one of technology selections. The advantages of Dielectric barrier non-thermal plasma for exhaust treatment lie in its simultaneous purification capacity, simple structure, insensitivity to the oil,and good adaptability in variable conditions.Starting from the current situation of the non-thermal plasma technology at home and abroad, this paper makes a brief analysis on the basic principles and methods of diesel engine emission control, especially on the PM and NOx emissions which are concerned by the relevant functional departments of state in recent years. Combined with the emissions regulations and test cycle, this paper declares that the non-thermal plasma technology is the key research of diesel engine emission control in the future and has a long-term research value.In the experimental study, a set of DBD(Dielectric Barrier Discharge) non-thermal plasma reactor was designed independently. Revolving around the influencing factors, a variety of experimental programs were designed. Compared these programs under the conditions of different power supply input voltages and frequencies, a series of findings are established:hydrocarbons can significantly improve the conversion rate of the reactor on NOx; NOx and PM conversion rate decreased with the increasing of the inlet component flow; the change of the circulation of the reactor can improve the removal of exhaust gas; vapor of the accession can significantly increased the NOx conversion; the comparative experiment of PM capture efficiency reveals that the reactor has a good treatment effect on PM; it is better to choose the high-voltage electrode of the reactor with a 0.6mm diameter, as well as a larger dielectric constant, a thin wall, and a mesh shape or other shapes, the reactor adapts well to the changes in the diesel exhaust temperature field, and it has a good effect in the low temperature area.Based on the application of the PFR(Plasma Plug Flow Reactor) module in the CHEMKIN-PRO, as well as the combination of dynamics of chemical reactions, the experiment makes analog simulations grouped by O2/NO/CO/N2/C3H6/CO2. The simulation studies show that the NOx coversion rate is high, which is accordance with the influencing factors of experimental programs.Beside, the influences of Axial Velocity and the electrode space on the reactor efficiency are added:there is little change in conversion rate with rising of rate; however, the experiment date shows that the conversion rate declines rapidly with a greater rate; electrode space should be less than2.0cm and should be easy to layout.This project based on the impact factors of the non-thermal plasma emission control, aims to explore the purification effect of exhaust gas, The experimental and simulation results both show this technique has a good prospect.