Experimental study on pollutant emission characteristics of diesel urea-based selective catalytic reduction system based on corrugated substrate

Abstract

In this study, a corrugated substrate of diesel engines for urea-based selective catalytic reduction (urea-SCR) with V2O5-WO3/TiO2 (V-SCR) and Cu-based (Cu-SCR) catalysts is proposed and the effects of the ammonia-to-nitrogen ratio α on the NOx emission, NH3 slip, and N2O emission were experimentally investigated on a diesel engine test bench with the World Harmonized Transient Cycle (WHTC). The volume ratio of the catalyst to the engine capacity is 1.6. With the increase of α, the NOx reduction reaction of V-SCR performed better NOx emission characteristics than that of Cu-SCR. When α increased from 1.0 to 1.2, the NOx emission of V-SCR and Cu-SCR decreased from 0.44 to 0.26 g/kW·h and from 0.63 to 0.36 g/kW·h, respectively. However, the NH3 slip of Cu-SCR was less because of its absorption capacity of NH3. The NOx conversion efficiency β and N2 selectivity δ of V-SCR outperformed those of Cu-SCR. At α = 1.1, β and δ of V-SCR were 1.07% and 3.25% higher than those of Cu-SCR, respectively. The dynamic response of V-SCR to NH3 showed high competitiveness compared to Cu-SCR. It was concluded that, based on the corrugated substrate, the V-SCR showed better pollutant emission characteristics than did the Cu-SCR.