Diesel Exhaust Particulate Characterization - Influence on DPF Regeneration Performance -

1. Diesel Exhaust Particulate Characterization- Influence on DPF Regeneration Performance - Internal thermocouples are used to get temperature distribution The DPF is then divided into several individual “reactors” with minimal thermal gradients For a given substrate the LT and HT kinetic parameters are similar LT and HT soot contribute to filtration efficiency and pressure drop in different ways LT soot is characterized by tight catalyst contact HT soot oxidation is not affected by the catalyst (loose contact) LT soot does not significantly increase pressure drop or filtration efficiency (during both filling and regeneration) D. Foster, T. Root, T. Kawai, E. Wirojsakunchai, E. Schroeder, N. Schmidt, C. Kolodziej, R. Yapaulo Procedure • Objective:In addition to filling performance the regeneration behavior of various DPFs with different collected soot is examined to better understand the mechanisms involved. • Lab Setup: Kinetic Parameter Estimation The rate constant as an Arrhenius expression DPFs are exposed to controlled temperature ramp and gas-phase emissions are monitored Good fit with experimental data The measured emissions are a convolution of the emissions from the smaller reaction volumes • Soot oxidation occurs in two distinct events: • Catalytic oxidation at low temps (~300 °C)  LT Peak • Thermal (carbon) oxidation (500 – 600 °C)  HT Peak Temperature Ramp: Room T to 700 °C (6.67 °C/min) Results Applying Kinetic Parameters to in-situ Regeneration Conclusions Mode 3, Catalyzed Cordierite, LT & HT Conceptual Model of Regeneration Stage 1: High filtration efficiency (intact soot cake) Stage 2: Decreasing filtration efficiency (transition) Stage 3: Low filtration efficiency (clean DPF) Mode 3, Catalyzed Cordierite, LT Oxy – acetylene Burner setup In – situ regeneration results in high thermal gradients and non-homogeneous soot oxidation rates Pressure drop and filtration efficiency correlate well with the amount of HT soot remaining in the filter Mode 3, Catalyzed Cordierite, HT