A Model Development for Evaluating Soot-NO_<i>x</i> Interactions in a Blended 2‑Way Diesel Particulate Filter/Selective Catalytic Reduction

Abstract

The 2-way diesel particulate filter/selective catalytic reduction (DPF/SCR) emission reduction system has been considered as a potential candidate for future emission standards owing to its advantages in cost savings and packaging flexibility. For the 2-way device, Cu–zeolite is coated inside the DPF substrate as nitrogen oxide (NO_<i>x</i>) reducing (DeNO_<i>x</i>) catalytic material. Therefore, when exhaust gas passes through the 2-way device, NO_<i>x</i> reduction and soot filtration occur simultaneously. However, the operating characteristics of the combinatorial device might be different from individual DPF and SCR devices. In this work, a previously developed model was improved to include soot filtration and oxidation. The model has been tested and validated with experimental data from a reactor flow bench in a systematic manner and applied to capture the effect of soot deposits on NO_<i>x</i> reduction performance in a 2-way DPF/SCR device. Accordingly, the soot oxidation characteristics of a 2-way device are investigated with various feed gas compositions. Then the effect of soot deposit on the SCR reaction is investigated in terms of deterioration of DeNO_<i>x</i> performance and the interaction between soot oxidation reactions and DeNO_<i>x</i> SCR reactions