Investigation on Reactor Configuration of Non Thermal Plasma Catalytic Hybrid Method for NOx Removal of Diesel Engine Exhaust
N. Osawa1, T. Suetomi1, Y. Hafuka1, K. Tsuha1, Y. Yoshioka2, and R. Hanaoka1
1Department of Electrical and Electronic Engineering, Kanazawa Institute of Technology, Ishikawa
2Office of Industry-University Collaboration, Kanazawa Institute of Technology, Ishikawa
Abstract— NOx (Nitrogen Oxides) emitted from diesel engines are one of the causes of air pollution. Recently, a urea-SCR method is going to be applied to diesel auto trucks. However, it is difficult to remove NOx at low temperatures. Up to now, many researchers have investigated a non thermal plasma catalytic hybrid method for NOx removal of diesel engine exhaust at low temperatures. In this research, we set up a NOx removal system from exhaust gas of a diesel engine generator by a combination of urea-SCR (Selective Catalytic Reduction) and non thermal plasma, and investigated the effect of reactor types on NOx removal performance. The results are obtained as follows; (1) the amount of the changes of NO concentration at rear side of the DBD (Dielectric Barrier Discharge) type reactor was larger than that of by the SD (Surface Discharge) type reactor, (2) in case of DBD type reactor, the maximum NOx removal efficiency was 26 g/kWh at the NOx removal rate of 8%. However it decreased with the increase of NOx removal rate and it attained to 11 g/kWh at 22%, (3) In case of the SD type reactor, the maximum NOx removal efficiency was 26 g/kWh at 8%. However it decreased drastically with the increase of NOx removal rate and it attained to 2.4 g/kWh at 16%. In summary, the DBD type reactor combined with catalysts is better than the SD type reactor as a plasma catalytic hybrid method for NOx removal of diesel engine exhaust gas.
Keywords— De-NOx, dielectric barrier discharge, surface discharge, urea-SCR, catalysts, photographic observation