A Non-Isothermal Kinetic Model for Modeling NH₃ Selective Catalytic Reduction Process over the Cu-ZSM-5 Monolithic Catalyst

Abstract

A non-isothermal kinetic model is proposed to study the selective catalytic reduction (SCR) of NH₃ over the Cu-ZSM-5 monolithic catalyst for improving the reduction efficiency of the NO gas exhausted from an internal combustion engine. In the kinetic model, the coupling of the chemical reaction, fluid flow, mass transfer, and heat transfer is considered for the numerical analysis. The model is solved by the finite element method. In this study, a simulation is conducted to verify the maththeoretical model. In the simulation, a three-dimensional non-isothermal model is adopted under different conditions of the gas temperature. The comparison between the simulated and the measured results reveals that the proposed non-isothermal kinetic model is accurate and reliable for analyzing the SCR process. From the simulated results, we found that the reduction efficiency of NO is significantly promoted by a high NH₃/NO ratio in the high gas-temperature range. Whereas in the low gas-temperature range, the reduction efficiency of NO is affected by a low ambient temperature. The present study could provide theoretical guidance for the parametric optimal study of the NH₃-SCR process to improe the reduction efficiency of NO.