Kinetic modeling of soot oxidation inside diesel particulate filter

The aim of this thesis work was to create a model for experimental data on kinetics and pressure drop of a lab-scale DPF setting using real-engine exhaust. Previous experimental work was carried out by testing four catalyzed and non-catalyzed mini-DPF substrates (cordierite, silicon carbide, Ceria coated silicon carbide, Pt/Ceria coated silicon carbide) fed with real heavy duty engine exhausts under several experimental conditions (w/o upstream diesel oxidation catalyst, short/long loading). Each of the samples was subsequently analyzed at different temperature levels under the effect of oxidant pulses (O2, NO2) in order to perform pre-loaded soot oxidation. Pressure drop across DPF and outgoing CO, CO2, NOx emissions were detected during the experiments. In this work, simulations have been performed using the commercial software GT-Suite from Gamma Technology, developing a single-channel filter 1-D model. By tuning of a set of pre-defined parameters, a software-based model for reproducing the experimental results was established. Another objective was to propose a simple kinetic mechanism able to describe the results of soot oxidation. The global kinetic model was replaced by a detailed kinetic model with consideration of a "pseudo-species" soot defined for modeling surface reactions in the soot cake. Combined O2 and NO2 oxidation was described. The general characterization of the system was obtained but not all the phenomena occurring were captured and further refinement on the kinetic mechanism is needed. However, the entire work represents a new frontier for aftertreatment analysis as it establishes a cross-over in between lab-scale experiment and real-operation settings.