Investigation on the Simulation of SCR Chemical Reaction

Abstract

Abstract. With the global environment worsening and the consciousness of protecting environment strengthening, the limitation of noxious gas from diesel engines is becoming more and more strictly. Selective catalytic reduction (SCR) aftertreatment system has been applied to reduce Nitrogen Oxides (NOx) as a key technology. The urea solution injected into the tailpipe decomposes to ammonia, which will react with NOx on the surface of SCR catalyst. The main purpose of this paper is to study the effect of different concentrations of NO, NO2 and NH3 on the reactions taking place with SCR catalyst by simulation. Based on mass transfer equations and chemical kinetics the simulation results predict the concentrations of NO, NO2 and NH3 accurately. The mass conservation equations of species are solved by the software MATLAB. Some regulations can be revealed to improve the NOx conversion efficiency and reduced the NH3 slip.