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Experimental and Modelling Study of Catalytic Diesel Soot Oxidation

Abstract : The objective of this Ph.D. thesis is the development of kinetic models for platinum-ceria-zirconia (Pt/CexZr1−xO2)-catalysed diesel particle filter (DPF) regeneration. Such models have a practical purpose in that they can be used to calculate source terms in 3D flow models, and they also have an intrinsic interest for the understanding of the mechanisms of catalysed soot oxidation. The core of this kinetic analysis consists in estimating Arrhenius parameters of a number of detailed reaction steps by fitting calculated curves to experimental ones. In doing so, the aim is not only to understand the roles of the different reactants, but also to investigate the efficacy and limitations of the modelling procedure for gas-solid heterogeneous reactions. Principal among the examined aspects is the feasibility of attributing physically meaningful values to individual parameters in large reaction mechanisms. The problem is approached by fitting one "subset"of reaction steps at a time. This procedure is illustrated by means of the cases of soot oxidation by NO, NO2 and/or O2, NO oxidation catalysed by ceria-based catalysts and soot oxidation catalysed by Pt/CexZr1−xO2. Interesting insights are gained into the mechanisms of these reactions, since the kinetics had often not been analysed thoroughly in the relevant literature. The fitting approach is shown to be effective as it allows for reproduction of several key species profiles in each of a number of experiments. Experiments used for these kinetic studies are temperature programmed tests in a fixed bed reactor, many of which were performed during the course of the study and data concerning others taken from the literature. In order to extract kinetic parameters from the temperature programmed data, a reactor model describing gas flow through a bed of particles and a mean field model of soot and catalyst surface chemistry are developed. The role of soot structure, ceria-zirconia composition/structure and soot/catalyst ratio on reaction are considered. Parameters used to deal with their effects are estimated.
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Contributor : Kirsten Leistner <>
Submitted on : Friday, September 6, 2013 - 8:59:25 AM
Last modification on : Wednesday, December 9, 2020 - 3:09:35 PM
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  • HAL Id : tel-00858763, version 1

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Kirsten Leistner. Experimental and Modelling Study of Catalytic Diesel Soot Oxidation. Chemical engineering. Université Pierre et Marie Curie - Paris VI, 2012. English. ⟨tel-00858763⟩

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