백금산화촉매를 통한 이산화질소(NO2)의 저감 특성에 관한 실험적 연구

Abstract

The reduction characteristics of NO2 to NO are experimentally studied over a platinum-based catalyst, especially at lower temperatures below about 200°C. In the present work, two types of steady-state experiments, engine bench and synthetic gas bench tests, are carried out in sequence. Steady-state engine bench tests with the DOC mounted on a light duty 4-cylinder 2.0 liter turbocharged diesel engine are performed and prove that CO plays a major role in NO2 abatement at temperatures below the light-off temperature of CO oxidation, about 200°C. Synthetic gas bench tests are then performed using synthetic gas mixtures with CO, C3H6, NO, NO2, O2, H2O and N2 in the 140~450°C T-range and show that both CO and C3H6 are capable of reducing NO2. It is noted that the reaction rate of NO2 with C3H6 is much higher than that with CO. At temperatures below about 200°C, the reduction of NO2 to NO is promoted with increasing CO concentration and NO2/NOX ratio and with decreasing O2 concentration, as well as with the presence of H2O.