Experimental and kinetic modeling study for N 2 O formation of NH 3 -SCR over commercial Cu-zeolite catalyst

In this paper, a systematic experimental and kinetic model investigation was conducted over Cu-SSZ-13 catalyst to study the DeNOx efficiency and N 2 O formation for selective catalytic reduction of NOx with NH 3 (NH 3 -SCR). The kinetic model was developed for various reactions to take place in the NH 3 -SCR system, including NH 3 adsorption/desorption, NH 3 oxidation, NO oxidation, standard SCR, fast SCR, slow SCR and N 2 O formation reactions. In addition, the reaction of N 2 O formation from NH 3 non-selective oxidation was taken into account. All the experiments were performed in a flow reactor with a feed stream near to the real application of diesel engine vehicles exhaust. The current model can satisfactorily predict the steady state conversion rate of various species at the reactor outlet and the effect of gas hourly space velocities and ammonia nitrogen ratio on N 2 O formation. The results show that the kinetic model can simulate the reaction process of the Cu-SSZ-13 catalyst well. This is significant for the optimization of NH 3 -SCR system for achieving the higher DeNOx efficiency and the lower N 2 O emission.