Numerical Study on Effects of Key Factors on Performance of CeO2-based Catalyzed Diesel Particulate Filter

Abstract

Catalyzed diesel particulate filter (CDPF) combines the functions of the oxidization catalyst and the diesel particulate filter. Due to good redox capacity and oxygen storage capacity, CeO2 is used as the catalyst of CDPF. Since the effects of key factors on the performance of CeO2-based CDPF were rarely reported, it was performed in this study based on a zero-dimensional numerical model using plug flow reactor in which a reaction mechanism was established and validated by the experiment of the thermal gravimetric analyzer. The effects of exhaust gas temperature and three defined parameters including the ratios of NO2 in NOx (α), NOx to soot (β), and catalyst coated amount to carbon loading amount (γ) on catalyst poisoning temperature, N2O concentration, NOx reduction rate and soot regeneration rate were investigated. The results show that the rising exhaust gas temperature causes the reduction of NOx concentration, and the NOx reduction rate comes to 66% when the catalyst poisoning temperature is reached. The soot regeneration rate and the N2O concentration first increase and then decrease as the exhaust gas temperature increases. Meanwhile, the higher exhaust gas temperature suppresses the production of N2O, but raises the possibility of catalyst poisoning. The increasing α and β result in the increase of soot regeneration rate and the decrease of NOx reduction rate. The catalyst poisoning temperature is improved at higher α and lower β. The soot regeneration rate has a fast increase with γ at first and then stabilizes rapidly. The results of this study are valuable to optimize the operation of CDPF.