Development of a Global Kinetic Model for a Commercial Lean NO_x Trap Automotive Catalyst Based on Laboratory Measurements

摘要

We summarize a global kinetic model for a commercial automotive Lean NO_x Trap (LNT) catalyst derived from laboratory flow reactor measurements at Oak Ridge National Laboratory (ORNL). The experimental measurements were made according to a modified version of a publicly shared protocol developed for characterizing the dynamic responses of LNT catalysts over a temperature range of 150— 550 °C under lean-rich cycling with CO, H_2, and C_3H_6 as the reductants. The resulting model includes three NO_x storage sites. The present model also includes reactions for oxygen storage, water gas shift, steam reforming, NO_x reduction, and N_2O and NH_3 generation. When implemented in ID integral reactor simulations of long-period cycling, the model was found to accurately predict the observed outlet concentrations of CO, H_2, C_3H_6, NO, NO_2, NH_3, and N_2O.