TY - JOUR
T1 - Comprehensive kinetic characterization of the oxidation and gasification of model and real diesel soot by nitrogen oxides and oxygen under engine exhaust conditions
T2 - Measurement, Langmuir-Hinshelwood, and Arrhenius parameters
AU - Messerer, A.
AU - Niessner, R.
AU - Pöschl, U.
N1 - Funding Information:
This work has been funded by the Bavarian Research Foundation (BFS) in the project “Development of a catalytic system for the continuous reduction of soot particle emissions of HDV diesel engines”. The authors would like to thank Christoph Adelhelm and Astrid Thalhammer (TU München; HBC and HDV experiments), Dieter Rothe and Eberhard Jacob (MAN Nutzfahrzeuge AG, Nürnberg, Germany; HDV soot sampling, analysis, and experiments), Christian Knab and Matthias Mangold (Oberland Mangold GmbH, Eschenlohe, Germany; oxidation catalyst and soot deposition structures), Jens-Oliver Müller and Robert Schlögl (Fritz–Haber-Institute of the Max–Planck-Society, Berlin, Germany), Christopher Simpson and Klaus Müllen (Max–Planck-Institute for Polymer Research, Mainz, Germany), as well as all other colleagues involved in the project work for support and stimulating discussions.
PY - 2006/2
Y1 - 2006/2
N2 - The reaction kinetics of the oxidation and gasification of four types of model and real diesel soot (light and heavy duty vehicle engine soot, graphite spark discharge soot, hexabenzocoronene) by nitrogen oxides and oxygen have been characterized for a wide range of conditions relevant for modern diesel engine exhaust and continuously regenerating particle trapping or filter systems (0-20% O2, 0-800 ppm NO2, 0-250 ppm NO, 0-8% H2O, 303-773 K, space velocities 1.3 × 104-5 × 105 h-1). Soot oxidation and NO2 adsorption experiments have been performed in a model catalytic system with temperature controlled flat bed reactors, novel aerosol particle deposition structures, and sensitive multicomponent gas analysis by FTIR spectroscopy. The experimental results have been analyzed and parameterized by means of a simple carbon mass-based pseudo-first-order rate equation, a shrinking core model, oxidant-specific rate coefficients, Langmuir-Hinshelwood formalisms (maximum rate coefficients and effective adsorption equilibrium constants), and Arrhenius equations (effective activation energies and pre-exponential factors), which allow to describe the rate of reaction as a function of carbon mass conversion, oxidant concentrations, and temperature. At temperatures up to 723 K the reaction was driven primarily by NO2 and enhanced by O2 and H 2O. Within the technically relevant concentration range the reaction rates were nearly independent of O2 and H2O variations, while the NO2 concentration dependence followed a Langmuir-Hinshelwood mechanism (saturation above ∼200 ppm). Reaction stoichiometry (NO2 consumption, CO and CO2 formation) and rate coefficients indicate that the reactions of NO2 and O 2 with soot proceed in parallel and are additive without significant non-linear interferences. The reactivity of the investigated diesel soot and model substances was positively correlated with their oxygen mass fraction and negatively correlated with their carbon mass fraction.
AB - The reaction kinetics of the oxidation and gasification of four types of model and real diesel soot (light and heavy duty vehicle engine soot, graphite spark discharge soot, hexabenzocoronene) by nitrogen oxides and oxygen have been characterized for a wide range of conditions relevant for modern diesel engine exhaust and continuously regenerating particle trapping or filter systems (0-20% O2, 0-800 ppm NO2, 0-250 ppm NO, 0-8% H2O, 303-773 K, space velocities 1.3 × 104-5 × 105 h-1). Soot oxidation and NO2 adsorption experiments have been performed in a model catalytic system with temperature controlled flat bed reactors, novel aerosol particle deposition structures, and sensitive multicomponent gas analysis by FTIR spectroscopy. The experimental results have been analyzed and parameterized by means of a simple carbon mass-based pseudo-first-order rate equation, a shrinking core model, oxidant-specific rate coefficients, Langmuir-Hinshelwood formalisms (maximum rate coefficients and effective adsorption equilibrium constants), and Arrhenius equations (effective activation energies and pre-exponential factors), which allow to describe the rate of reaction as a function of carbon mass conversion, oxidant concentrations, and temperature. At temperatures up to 723 K the reaction was driven primarily by NO2 and enhanced by O2 and H 2O. Within the technically relevant concentration range the reaction rates were nearly independent of O2 and H2O variations, while the NO2 concentration dependence followed a Langmuir-Hinshelwood mechanism (saturation above ∼200 ppm). Reaction stoichiometry (NO2 consumption, CO and CO2 formation) and rate coefficients indicate that the reactions of NO2 and O 2 with soot proceed in parallel and are additive without significant non-linear interferences. The reactivity of the investigated diesel soot and model substances was positively correlated with their oxygen mass fraction and negatively correlated with their carbon mass fraction.
KW - Activation energy
KW - Adsorption
KW - Combustion
KW - Oxidation
KW - Soot
UR - http://www.scopus.com/inward/record.url?scp=27344441838&partnerID=8YFLogxK
U2 - 10.1016/j.carbon.2005.07.017
DO - 10.1016/j.carbon.2005.07.017
M3 - Article
AN - SCOPUS:27344441838
SN - 0008-6223
VL - 44
SP - 307
EP - 324
JO - Carbon
JF - Carbon
IS - 2
ER -