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CFD method to couple three - dimensional transport and reaction inside catalyst particles to the fixed bed flow field / Anthony G. Dixon in Industrial & engineering chemistry research, Vol. 49 N° 19 (Octobre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 19 (Octobre 2010) . - pp. 9012–9025 Titre : CFD method to couple three - dimensional transport and reaction inside catalyst particles to the fixed bed flow field Type de document : texte imprimé Auteurs : Anthony G. Dixon, Auteur ; M. Ertan Taskin, Auteur ; Michiel Nijemeisland, Auteur Année de publication : 2010 Article en page(s) : pp. 9012–9025 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Computational  fluid  dynamics  Catalyst  particles  Flow  field Résumé : A new method is presented to couple the fluid flow in a fixed bed to the transport and reaction inside a catalyst particle, using computational fluid dynamics (CFD). The particle is modeled as solid, allowing no-slip surface flow boundary conditions to be used. Species transport inside the particle is represented by user-defined scalars, and the catalytic reactions are represented by user-defined functions. The new method is validated using standard cases for which exact results are known. Previous work has used a porous representation of the catalyst particle, which results in inaccurate temperature and species profiles due to an artifact of convective flux across the particle−fluid interface. This also gives incorrect values of the particle-to-fluid heat transfer coefficient, compared to standard correlations. Simulation results are presented for methane steam reforming using spherical particles in a wall segment, under tube inlet and midtube conditions, to illustrate the solid particle method. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100298q [article] CFD method to couple three - dimensional transport and reaction inside catalyst particles to the fixed bed flow field [texte imprimé] / Anthony G. Dixon, Auteur ; M. Ertan Taskin, Auteur ; Michiel Nijemeisland, Auteur . - 2010 . - pp. 9012–9025. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 19 (Octobre 2010) . - pp. 9012–9025 Mots-clés : Computational  fluid  dynamics  Catalyst  particles  Flow  field Résumé : A new method is presented to couple the fluid flow in a fixed bed to the transport and reaction inside a catalyst particle, using computational fluid dynamics (CFD). The particle is modeled as solid, allowing no-slip surface flow boundary conditions to be used. Species transport inside the particle is represented by user-defined scalars, and the catalytic reactions are represented by user-defined functions. The new method is validated using standard cases for which exact results are known. Previous work has used a porous representation of the catalyst particle, which results in inaccurate temperature and species profiles due to an artifact of convective flux across the particle−fluid interface. This also gives incorrect values of the particle-to-fluid heat transfer coefficient, compared to standard correlations. Simulation results are presented for methane steam reforming using spherical particles in a wall segment, under tube inlet and midtube conditions, to illustrate the solid particle method. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100298q

Flow, transport, and reaction interactions for cylindrical particles with strongly endothermic reactions / M. Ertan Taskin in Industrial & engineering chemistry research, Vol. 49 N° 19 (Octobre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 19 (Octobre 2010) . - pp. 9026–9037 Titre : Flow, transport, and reaction interactions for cylindrical particles with strongly endothermic reactions Type de document : texte imprimé Auteurs : M. Ertan Taskin, Auteur ; Alexandre Troupel, Auteur ; Anthony G. Dixon, Auteur Année de publication : 2010 Article en page(s) : pp. 9026–9037 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalyst  particles  Methane  steam  reforming  Dehydrogenation Résumé : Interactions between reaction rates, conduction, and diffusion inside catalyst particles can be complex, especially when influenced by nonuniform surface conditions produced by the flow field external to the particle, or by the highly directional temperature field near a heated tube wall. In this work, a three-dimensional, realistic flow field was coupled to species and energy balances in cylindrical catalyst particles using computational fluid dynamics (CFD). Two strongly endothermic reactions were studied: methane steam reforming and propane dehydrogenation. Detailed pellet surface and intraparticle temperature, species, and reaction rate distributions were obtained for a near-wall particle. Nonuniform and nonsymmetric surface and intraparticle variations were observed. These effects are primarily attributed to the steep temperature gradients at the tube wall, as well as depletion of the reactants in regions of low or stagnant flow where particles approach each other closely. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1003619 [article] Flow, transport, and reaction interactions for cylindrical particles with strongly endothermic reactions [texte imprimé] / M. Ertan Taskin, Auteur ; Alexandre Troupel, Auteur ; Anthony G. Dixon, Auteur . - 2010 . - pp. 9026–9037. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 19 (Octobre 2010) . - pp. 9026–9037 Mots-clés : Catalyst  particles  Methane  steam  reforming  Dehydrogenation Résumé : Interactions between reaction rates, conduction, and diffusion inside catalyst particles can be complex, especially when influenced by nonuniform surface conditions produced by the flow field external to the particle, or by the highly directional temperature field near a heated tube wall. In this work, a three-dimensional, realistic flow field was coupled to species and energy balances in cylindrical catalyst particles using computational fluid dynamics (CFD). Two strongly endothermic reactions were studied: methane steam reforming and propane dehydrogenation. Detailed pellet surface and intraparticle temperature, species, and reaction rate distributions were obtained for a near-wall particle. Nonuniform and nonsymmetric surface and intraparticle variations were observed. These effects are primarily attributed to the steep temperature gradients at the tube wall, as well as depletion of the reactants in regions of low or stagnant flow where particles approach each other closely. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1003619