Documents disponibles écrits par cet auteur

Drying of supported catalysts / Xue Liu in Industrial & engineering chemistry research, Vol. 49 N° 6 (Mars 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 6 (Mars 2010) . - pp. 2649–2657 Titre : Drying of supported catalysts : a comparison of model predictions and experimental measurements of metal profiles Type de document : texte imprimé Auteurs : Xue Liu, Auteur ; Johannes G. Khinast, Auteur ; Benjamin J. Glasser, Auteur Année de publication : 2010 Article en page(s) : pp. 2649–2657 Note générale : Industrial Chemistry Langues : Anglais (eng) Mots-clés : Drying  of  Supported  Catalysts  Comparison  Predictions  Experimental  Measurements  Metal  Profiles Résumé : Supported metal catalysts are used in many industrial applications. Experiments have shown that drying may significantly impact the metal distribution within the support. Therefore we need to have a fundamental understanding of drying. In this work, a theoretical model is established to predict the drying process, and the model predictions are compared with experimental measurements of a nickel/alumina system. It is found that egg-shell profiles can be enhanced by increasing the drying temperature or the initial metal concentration if the metal loading is low. For high metal loadings, nearly uniform profiles are observed after drying. We have also investigated how breakage of the liquid film inside the pores of the support can affect the metal distribution during drying. It was found that film-breakage has a significant impact on the metal distribution, and it is important to correctly capture film-breakage in the model in order to get good experimental agreement. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9014606 [article] Drying of supported catalysts : a comparison of model predictions and experimental measurements of metal profiles [texte imprimé] / Xue Liu, Auteur ; Johannes G. Khinast, Auteur ; Benjamin J. Glasser, Auteur . - 2010 . - pp. 2649–2657. Industrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 6 (Mars 2010) . - pp. 2649–2657 Mots-clés : Drying  of  Supported  Catalysts  Comparison  Predictions  Experimental  Measurements  Metal  Profiles Résumé : Supported metal catalysts are used in many industrial applications. Experiments have shown that drying may significantly impact the metal distribution within the support. Therefore we need to have a fundamental understanding of drying. In this work, a theoretical model is established to predict the drying process, and the model predictions are compared with experimental measurements of a nickel/alumina system. It is found that egg-shell profiles can be enhanced by increasing the drying temperature or the initial metal concentration if the metal loading is low. For high metal loadings, nearly uniform profiles are observed after drying. We have also investigated how breakage of the liquid film inside the pores of the support can affect the metal distribution during drying. It was found that film-breakage has a significant impact on the metal distribution, and it is important to correctly capture film-breakage in the model in order to get good experimental agreement. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9014606

Fast reactions in bubbly flows / Stefan Radl in Industrial & engineering chemistry research, Vol. 49 N° 21 (Novembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10715-10729 Titre : Fast reactions in bubbly flows : Film model and micromixing effects Type de document : texte imprimé Auteurs : Stefan Radl, Auteur ; Daniele Suzzi, Auteur ; Johannes G. Khinast, Auteur Année de publication : 2011 Article en page(s) : pp. 10715-10729 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Micromixing  Modeling  Bubble  flow  Fast  reaction Résumé : In our work, we focus on the Euler-Lagrange strategy to simulate bubbly flows and fast chemical reactions. We propose a film model to account for fast, multistep chemical reactions near the gas—liquid interface. A combination of such a film model with Euler—Lagrange simulations for bubbly flows has not been used before. Also, we account for micromixing effects with respect to chemical reactions in the liquid bulk by solving for the variance of the concentration field. To validate our model predictions for multiphase flow and reactive mixing, we compare our results with literature data and find excellent agreement. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23447965 [article] Fast reactions in bubbly flows : Film model and micromixing effects [texte imprimé] / Stefan Radl, Auteur ; Daniele Suzzi, Auteur ; Johannes G. Khinast, Auteur . - 2011 . - pp. 10715-10729. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10715-10729 Mots-clés : Micromixing  Modeling  Bubble  flow  Fast  reaction Résumé : In our work, we focus on the Euler-Lagrange strategy to simulate bubbly flows and fast chemical reactions. We propose a film model to account for fast, multistep chemical reactions near the gas—liquid interface. A combination of such a film model with Euler—Lagrange simulations for bubbly flows has not been used before. Also, we account for micromixing effects with respect to chemical reactions in the liquid bulk by solving for the variance of the concentration field. To validate our model predictions for multiphase flow and reactive mixing, we compare our results with literature data and find excellent agreement. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23447965

Mixing and dissolution processes of pharmaceutical bulk materials in stirred tanks / Thomas Hormann in Industrial & engineering chemistry research, Vol. 50 N° 21 (Novembre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 21 (Novembre 2011) . - pp. 12011-12025 Titre : Mixing and dissolution processes of pharmaceutical bulk materials in stirred tanks : experimental and numerical investigations Type de document : texte imprimé Auteurs : Thomas Hormann, Auteur ; Daniele Suzzi, Auteur ; Johannes G. Khinast, Auteur Année de publication : 2011 Article en page(s) : pp. 12011-12025 Note générale : Chimie induistrielle Langues : Anglais (eng) Mots-clés : Stirred  vessel  Bulk  material  Dissolution  Mixing Résumé : Numerical analysis of mixing and dissolution processes is becoming increasingly important for graining a process understanding and thus optimizing the production. Due to the increasing costs and shortage of raw materials, "in-silico" techniques are currently employed together with standard experimental analyses. Numerical simulations have proven to be a useful tool for understanding and optimizing industrial mixing problems. However, such simulations are still in the research phase. Although Computational Fluid Dynamics (CFD) is a well-developed and validated method, for more complex applications (e.g., industrial mixing) much work is still required to obtain reliable results quickly enough. In this work we focused on the simulation of mixing and dissolution of a bulk powder in a moderately viscous solution in an unbaffled stirred tank reactor typically used in the chemical and pharmaceutical industries. Estimations were made with regard to optimizing batch sizes, tank geometry, impeller type, and placement and process variables, such as the impeller agitation speed. In addition, the vortex formation of the liquid surface, the feeding position of the bulk powder, and the dissolution process of the solid particles that represent the bulk powder were manipulated. Finally, a quantitative comparison of different stirring systems and scale-up studies was prepared. The time-dependent and turbulent flow of the mixture was studied by solving the Reynolds-averaged Navier-Stokes equations. The numerical predictions of the flow field were validated by means of high-speed camera images and particle image velodmetry postprocessing techniques. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24697521 [article] Mixing and dissolution processes of pharmaceutical bulk materials in stirred tanks : experimental and numerical investigations [texte imprimé] / Thomas Hormann, Auteur ; Daniele Suzzi, Auteur ; Johannes G. Khinast, Auteur . - 2011 . - pp. 12011-12025. Chimie induistrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 21 (Novembre 2011) . - pp. 12011-12025 Mots-clés : Stirred  vessel  Bulk  material  Dissolution  Mixing Résumé : Numerical analysis of mixing and dissolution processes is becoming increasingly important for graining a process understanding and thus optimizing the production. Due to the increasing costs and shortage of raw materials, "in-silico" techniques are currently employed together with standard experimental analyses. Numerical simulations have proven to be a useful tool for understanding and optimizing industrial mixing problems. However, such simulations are still in the research phase. Although Computational Fluid Dynamics (CFD) is a well-developed and validated method, for more complex applications (e.g., industrial mixing) much work is still required to obtain reliable results quickly enough. In this work we focused on the simulation of mixing and dissolution of a bulk powder in a moderately viscous solution in an unbaffled stirred tank reactor typically used in the chemical and pharmaceutical industries. Estimations were made with regard to optimizing batch sizes, tank geometry, impeller type, and placement and process variables, such as the impeller agitation speed. In addition, the vortex formation of the liquid surface, the feeding position of the bulk powder, and the dissolution process of the solid particles that represent the bulk powder were manipulated. Finally, a quantitative comparison of different stirring systems and scale-up studies was prepared. The time-dependent and turbulent flow of the mixture was studied by solving the Reynolds-averaged Navier-Stokes equations. The numerical predictions of the flow field were validated by means of high-speed camera images and particle image velodmetry postprocessing techniques. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24697521