Documents disponibles écrits par cet auteur

Experimental and modeling analysis of methane partial oxidation / Alessandra Beretta in Industrial & engineering chemistry research, Vol. 48 N° 8 (Avril 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 8 (Avril 2009) . - pp. 3825–3836 Titre : Experimental and modeling analysis of methane partial oxidation : transient and steady-state behavior of rh-coated honeycomb monoliths Type de document : texte imprimé Auteurs : Alessandra Beretta, Auteur ; Gianpiero Groppi, Auteur ; Matteo Lualdi, Auteur Année de publication : 2009 Article en page(s) : pp. 3825–3836 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Rh-coated  honeycomb  monoliths  Methane  partial  oxidation  Steady  state Résumé : The present study consists of an experimental and theoretical study of the performance of Rh-coated honeycomb monoliths for methane partial oxidation. The thermal behavior of Rh-coated honeycomb monoliths was studied under representative operating conditions, at steady state and during light-off. Model analysis (based on a dynamic heterogeneous reactor model that incorporates a kinetic scheme of the process independently developed, and well-assessed correlations for heat and mass transfer) provided a key for interpreting the observed effects. The comprehension of how transport phenomena and surface kinetics affect the reactor behavior leads to the conclusion that the feasibility of small-scale production of syngas via CH4 catalytic partial oxidation relies on thermal management of the short contact time reactor and not the obtainment of high syngas yields (which is not a challenging task). Severe operating conditions (and high surface temperatures) can deplete the catalyst activity and cause unstable reactor operation. Guidelines for optimal reactor design are proposed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8017143 [article] Experimental and modeling analysis of methane partial oxidation : transient and steady-state behavior of rh-coated honeycomb monoliths [texte imprimé] / Alessandra Beretta, Auteur ; Gianpiero Groppi, Auteur ; Matteo Lualdi, Auteur . - 2009 . - pp. 3825–3836. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 8 (Avril 2009) . - pp. 3825–3836 Mots-clés : Rh-coated  honeycomb  monoliths  Methane  partial  oxidation  Steady  state Résumé : The present study consists of an experimental and theoretical study of the performance of Rh-coated honeycomb monoliths for methane partial oxidation. The thermal behavior of Rh-coated honeycomb monoliths was studied under representative operating conditions, at steady state and during light-off. Model analysis (based on a dynamic heterogeneous reactor model that incorporates a kinetic scheme of the process independently developed, and well-assessed correlations for heat and mass transfer) provided a key for interpreting the observed effects. The comprehension of how transport phenomena and surface kinetics affect the reactor behavior leads to the conclusion that the feasibility of small-scale production of syngas via CH4 catalytic partial oxidation relies on thermal management of the short contact time reactor and not the obtainment of high syngas yields (which is not a challenging task). Severe operating conditions (and high surface temperatures) can deplete the catalyst activity and cause unstable reactor operation. Guidelines for optimal reactor design are proposed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8017143

Experimental and modeling analysis of the thermal behavior of an autothermal C3H8 catalytic partial oxidation reformer / Dario Livio in Industrial & engineering chemistry research, Vol. 51 N° 22 (Juin 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 22 (Juin 2012) . - pp. 7573–7583 Titre : Experimental and modeling analysis of the thermal behavior of an autothermal C3H8 catalytic partial oxidation reformer Type de document : texte imprimé Auteurs : Dario Livio, Auteur ; Alessandro Donazzi, Auteur ; Alessandra Beretta, Auteur Année de publication : 2012 Article en page(s) : pp. 7573–7583 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Thermal  behavior  Partial  oxidation Résumé : In this work, a spatially resolved sampling technique is applied to characterize the performance of a C3H8 CPO reformer and to compare it with that of a CH4 reformer. The case of Rh-coated honeycomb catalysts is examined. The axial profiles show that higher temperatures are reached in C3H8 CPO, especially at the reactor inlet. Surface hot-spot temperatures around 950 °C lead the catalyst to rapid loss of activity. A detailed model analysis is also applied to better understand the reasons for the observed differences of the thermal behavior. On one hand, the heat release via oxidation reactions is controlled by O2 mass transfer rate and thus proportional to O2 inlet concentration, which is 20% higher in the C3H8/air mixture at equal C/O ratio. On the other hand, while CH4 steam reforming is partly chemically controlled, C3H8 steam reforming is mainly limited by gas–solid diffusion. Thus, a less efficient balance between exo- and endothermic reactions occurs in the case of C3H8 CPO, and this results in much higher hot-spot temperatures. As a consequence, specific strategies for the optimization of the thermal behavior are required depending on the fuel. Modeling of the C3H8 CPO results shows that an increased catalyst load or a suitable aspect ratio of the reactor, combined with a decrease of the flow rate, produces a beneficial moderation of the hot-spot temperature of the catalytic wall. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202098q [article] Experimental and modeling analysis of the thermal behavior of an autothermal C3H8 catalytic partial oxidation reformer [texte imprimé] / Dario Livio, Auteur ; Alessandro Donazzi, Auteur ; Alessandra Beretta, Auteur . - 2012 . - pp. 7573–7583. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 22 (Juin 2012) . - pp. 7573–7583 Mots-clés : Thermal  behavior  Partial  oxidation Résumé : In this work, a spatially resolved sampling technique is applied to characterize the performance of a C3H8 CPO reformer and to compare it with that of a CH4 reformer. The case of Rh-coated honeycomb catalysts is examined. The axial profiles show that higher temperatures are reached in C3H8 CPO, especially at the reactor inlet. Surface hot-spot temperatures around 950 °C lead the catalyst to rapid loss of activity. A detailed model analysis is also applied to better understand the reasons for the observed differences of the thermal behavior. On one hand, the heat release via oxidation reactions is controlled by O2 mass transfer rate and thus proportional to O2 inlet concentration, which is 20% higher in the C3H8/air mixture at equal C/O ratio. On the other hand, while CH4 steam reforming is partly chemically controlled, C3H8 steam reforming is mainly limited by gas–solid diffusion. Thus, a less efficient balance between exo- and endothermic reactions occurs in the case of C3H8 CPO, and this results in much higher hot-spot temperatures. As a consequence, specific strategies for the optimization of the thermal behavior are required depending on the fuel. Modeling of the C3H8 CPO results shows that an increased catalyst load or a suitable aspect ratio of the reactor, combined with a decrease of the flow rate, produces a beneficial moderation of the hot-spot temperature of the catalytic wall. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202098q