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Papers by Bengt Andersson
Journal of Catalysis, 1999
The Canadian Journal of Chemical Engineering, 2000
ABSTRACT Several Mars—Van Krevelen-type redox kinetic models were developed for the catalytic oxi... more ABSTRACT Several Mars—Van Krevelen-type redox kinetic models were developed for the catalytic oxidative dehydrogenation of propane and examined for their ability to predict high propene yields at low oxygen/propane feed ratios. The intent in this study was to use modelling as a means of extracting further mechanistic insight from experimental data rather than to identify the best model. Thus, a conventional redox model with a consecutive reaction mechanism and a single pathway for the production of carbon oxides predicts higher propene selectivity but only at the expense of low propane conversion. Experimental data indicated, however, that even at the same propane conversion, propene selectivity increased as the oxygen partial pressure was lowered. Models that successfully describe the data had an additional carbon oxide production path involving the reaction of propane with deeply oxidizing surface oxygen species. Kinetic models and experimental data examined do not fully resolve how these deeply oxidizing surface oxygen species are formed. However, they do reflect the accepted view that lattice oxygen selectively produces propene whereas more weakly bound surface adsorbed oxygen reacts to completely oxidize propane.Plusieurs modèles cinétiques redox de type Mars—Van Krevelen ont été mis au point pour la déshydrogénation oxydative catalytique du propane et examinés pour déterminer leur capacité à prédire de hauts rendements de propène à de faibles rapports d'alimentation oxygène/propane. Le but de cette étude était d'utiliser la modélisation pour avoir un meilleur aperçu des aspects mécanistiques à partir de données expérimentales plutǒt que de déterminer le meilleur modèle. Ainsi, un modèle redox classique basée sur un mécanisme de réactions consécutives et un chemin unique pour produire des oxydes de carbone prédit une meilleure sélectivité du propène mais seulement au dépens d'une faible conversion de propane. Des données expérimentales indiquent, cependant, que měme à conversion de propane identique, la sélectivité du propène augmente alors que la pression partielle de l'oxygène est réduite. Des modèles décrivant avec succès les données avaient un chemin de production d'oxyde de carbone supplémentaire impliquant la réaction du propane avec des espèces d'oxygène de surface s'oxydant fortement. Les modèles cinétiques et les données expérimentales examinés ne disent pas complètement comment se forment ces espèces d'oxygène s'oxydant fortement. Toutefois, ils reflètent l'idée acceptée que l'oxygène en réseau produit sélectivement du propène tandis que l'oxygène adsorbé en surface avec des liaisons faibles réaglt pour oxyder complètement le propane.
J Catal, 2004
A new method for preparing supported catalysts, in which Pt was distributed in locally high conce... more A new method for preparing supported catalysts, in which Pt was distributed in locally high concentrations on the γ-Al2O3 support, was studied. These catalysts were compared with a conventionally prepared Pt/γ-Al2O3 catalyst in which Pt was deposited evenly on the support. The object was to ascertain whether it is possible to prepare catalysts that retain heat released from exothermic reactions to a higher extent and thereby become more low-temperature active than a conventionally prepared catalyst. A significant improvement of the activity was observed for the catalysts prepared with locally high Pt concentrations when CO (1%, 1000 and 100 ppm) was oxidized at a constant O2 concentration (10%). The improved activity is discussed in terms of heat transfer, mass transfer, and structure sensitivity. Differences in heat transfer appear to be the least probable reason for the enhanced activity for the catalysts with locally higher Pt concentrations, whereas structural effects also seem to be an unlikely explanation. Differences in mass transfer seem, however, to be a more likely reason for the improved activity.
The Journal of Physical Chemistry B, 2001
Modeling and flow reactor experiments were used to study the kinetics of NO x storage/release on ... more Modeling and flow reactor experiments were used to study the kinetics of NO x storage/release on a Pt/BaO/Al2O3 model catalyst. The mechanism for this concept can be divided into four steps:(i) NO to NO2 oxidation on Pt,(ii) NO2 storage on BaO,(iii) NO x ...
A mean field model, for storage and desorption of NOx in a Pt/BaO/Al2O3 catalyst is developed usi... more A mean field model, for storage and desorption of NOx in a Pt/BaO/Al2O3 catalyst is developed using data from flow reactor experiments. This relatively complex system is divided into five smaller sub-systems and the model is divided into the following steps:(i) ...
Chemical Engineering Science, Nov 1, 2000
ABSTRACT The oxidation of CO in air has been studied using spherical alumina pellets with varying... more ABSTRACT The oxidation of CO in air has been studied using spherical alumina pellets with varying radial platinum distributions. Shell and homogeneous catalysts have bi on prepared with the same total amount of platinum. Go-impregnation of chloroplatinic acid and citric acid was used to obtain the homogeneous distribution. Temperature ramp experiments in a flow reactor showed significant differences in light-off behavior for the two catalysts. Compared to the shell catalyst, the conversion of CO started at lower temperatures when using the homogeneous catalyst, but higher temperatures were needed for total conversion. Steady-stale experiments performed in a micro Berty tank reactor with the homogeneous catalyst were used to derive two different kinetic models for the oxidation. One of the kinetic expressions was used to simulate the catalytic activity in a steady-state flow reactor system. The maximum temperature gain which can be achieved by placing the active material at the optimum position in the pellet, in comparison to an infinitesimal shell distribution, was found to be 48 degreesC at 95% conversion for 1.0% CO.
Aiche Journal, 2007
... Bubble Trapping and Coalescence at the Leeward Side of Baffles in Reactors Stired by Rushton ... more ... Bubble Trapping and Coalescence at the Leeward Side of Baffles in Reactors Stired by Rushton Turbines. Sudiyo, Rahman, 1971-(författare) Chalmers tekniska högskola, Institutionen för kemi-och bioteknik, Kemisk reaktionsteknik Andersson, Bengt, 1947-(författare ...
Industrial Engineering Chemistry Research, 1988
Chemical Engineering Journal, Jul 15, 2009
Http Dx Doi Org 10 1080 01614948808080809, Jan 3, 2007
ABSTRACT The use of monoliths in automotive emission control systems has dominated the applicatio... more ABSTRACT The use of monoliths in automotive emission control systems has dominated the applications of monoliths. However, other applications have also become of interest due to unique features of monoliths.
Journal of Catalysis, 1999
The Canadian Journal of Chemical Engineering, 2000
ABSTRACT Several Mars—Van Krevelen-type redox kinetic models were developed for the catalytic oxi... more ABSTRACT Several Mars—Van Krevelen-type redox kinetic models were developed for the catalytic oxidative dehydrogenation of propane and examined for their ability to predict high propene yields at low oxygen/propane feed ratios. The intent in this study was to use modelling as a means of extracting further mechanistic insight from experimental data rather than to identify the best model. Thus, a conventional redox model with a consecutive reaction mechanism and a single pathway for the production of carbon oxides predicts higher propene selectivity but only at the expense of low propane conversion. Experimental data indicated, however, that even at the same propane conversion, propene selectivity increased as the oxygen partial pressure was lowered. Models that successfully describe the data had an additional carbon oxide production path involving the reaction of propane with deeply oxidizing surface oxygen species. Kinetic models and experimental data examined do not fully resolve how these deeply oxidizing surface oxygen species are formed. However, they do reflect the accepted view that lattice oxygen selectively produces propene whereas more weakly bound surface adsorbed oxygen reacts to completely oxidize propane.Plusieurs modèles cinétiques redox de type Mars—Van Krevelen ont été mis au point pour la déshydrogénation oxydative catalytique du propane et examinés pour déterminer leur capacité à prédire de hauts rendements de propène à de faibles rapports d'alimentation oxygène/propane. Le but de cette étude était d'utiliser la modélisation pour avoir un meilleur aperçu des aspects mécanistiques à partir de données expérimentales plutǒt que de déterminer le meilleur modèle. Ainsi, un modèle redox classique basée sur un mécanisme de réactions consécutives et un chemin unique pour produire des oxydes de carbone prédit une meilleure sélectivité du propène mais seulement au dépens d'une faible conversion de propane. Des données expérimentales indiquent, cependant, que měme à conversion de propane identique, la sélectivité du propène augmente alors que la pression partielle de l'oxygène est réduite. Des modèles décrivant avec succès les données avaient un chemin de production d'oxyde de carbone supplémentaire impliquant la réaction du propane avec des espèces d'oxygène de surface s'oxydant fortement. Les modèles cinétiques et les données expérimentales examinés ne disent pas complètement comment se forment ces espèces d'oxygène s'oxydant fortement. Toutefois, ils reflètent l'idée acceptée que l'oxygène en réseau produit sélectivement du propène tandis que l'oxygène adsorbé en surface avec des liaisons faibles réaglt pour oxyder complètement le propane.
J Catal, 2004
A new method for preparing supported catalysts, in which Pt was distributed in locally high conce... more A new method for preparing supported catalysts, in which Pt was distributed in locally high concentrations on the γ-Al2O3 support, was studied. These catalysts were compared with a conventionally prepared Pt/γ-Al2O3 catalyst in which Pt was deposited evenly on the support. The object was to ascertain whether it is possible to prepare catalysts that retain heat released from exothermic reactions to a higher extent and thereby become more low-temperature active than a conventionally prepared catalyst. A significant improvement of the activity was observed for the catalysts prepared with locally high Pt concentrations when CO (1%, 1000 and 100 ppm) was oxidized at a constant O2 concentration (10%). The improved activity is discussed in terms of heat transfer, mass transfer, and structure sensitivity. Differences in heat transfer appear to be the least probable reason for the enhanced activity for the catalysts with locally higher Pt concentrations, whereas structural effects also seem to be an unlikely explanation. Differences in mass transfer seem, however, to be a more likely reason for the improved activity.
The Journal of Physical Chemistry B, 2001
Modeling and flow reactor experiments were used to study the kinetics of NO x storage/release on ... more Modeling and flow reactor experiments were used to study the kinetics of NO x storage/release on a Pt/BaO/Al2O3 model catalyst. The mechanism for this concept can be divided into four steps:(i) NO to NO2 oxidation on Pt,(ii) NO2 storage on BaO,(iii) NO x ...
A mean field model, for storage and desorption of NOx in a Pt/BaO/Al2O3 catalyst is developed usi... more A mean field model, for storage and desorption of NOx in a Pt/BaO/Al2O3 catalyst is developed using data from flow reactor experiments. This relatively complex system is divided into five smaller sub-systems and the model is divided into the following steps:(i) ...
Chemical Engineering Science, Nov 1, 2000
ABSTRACT The oxidation of CO in air has been studied using spherical alumina pellets with varying... more ABSTRACT The oxidation of CO in air has been studied using spherical alumina pellets with varying radial platinum distributions. Shell and homogeneous catalysts have bi on prepared with the same total amount of platinum. Go-impregnation of chloroplatinic acid and citric acid was used to obtain the homogeneous distribution. Temperature ramp experiments in a flow reactor showed significant differences in light-off behavior for the two catalysts. Compared to the shell catalyst, the conversion of CO started at lower temperatures when using the homogeneous catalyst, but higher temperatures were needed for total conversion. Steady-stale experiments performed in a micro Berty tank reactor with the homogeneous catalyst were used to derive two different kinetic models for the oxidation. One of the kinetic expressions was used to simulate the catalytic activity in a steady-state flow reactor system. The maximum temperature gain which can be achieved by placing the active material at the optimum position in the pellet, in comparison to an infinitesimal shell distribution, was found to be 48 degreesC at 95% conversion for 1.0% CO.
Aiche Journal, 2007
... Bubble Trapping and Coalescence at the Leeward Side of Baffles in Reactors Stired by Rushton ... more ... Bubble Trapping and Coalescence at the Leeward Side of Baffles in Reactors Stired by Rushton Turbines. Sudiyo, Rahman, 1971-(författare) Chalmers tekniska högskola, Institutionen för kemi-och bioteknik, Kemisk reaktionsteknik Andersson, Bengt, 1947-(författare ...
Industrial Engineering Chemistry Research, 1988
Chemical Engineering Journal, Jul 15, 2009
Http Dx Doi Org 10 1080 01614948808080809, Jan 3, 2007
ABSTRACT The use of monoliths in automotive emission control systems has dominated the applicatio... more ABSTRACT The use of monoliths in automotive emission control systems has dominated the applications of monoliths. However, other applications have also become of interest due to unique features of monoliths.