Modeling of NOx Storage and Reduction for Diesel Exhaust Emission Control

A one-dimensional two-phase model of an adsorptive catalytic monolith reactor (used as Lean NOx Trap, LNT) is developed and analyzed. The model simulates the features of NOx storage and reduction (NSR), a periodic process involving the sequential trapping on a storage component and conversion of NOx to nitrogen under lean conditions found in the exhaust of lean burn and diesel vehicles. The effect of design and operating parameters, such as the lean and rich times and feed temperature, on NO₂ conversion is examined. Using a relatively simple kinetic model and without any attempt to fit data, the LNT model predicts the dependencies of NO₂ conversion on several feed parameters that are in good agreement with experimental observations.