Documents disponibles écrits par cet auteur

Exploring the essence of three-phase packed distillation / Chen, Liang in Industrial & engineering chemistry research, Vol. 49 N° 2 (Janvier 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 822–837 Titre : Exploring the essence of three-phase packed distillation : substantial mass transfer computation Type de document : texte imprimé Auteurs : Chen, Liang, Auteur ; Jens-Uwe Repke, Auteur ; Günter Wozny, Auteur Année de publication : 2010 Article en page(s) : pp 822–837 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Essence  Mass  transfer  Vapor  Liquid. Résumé : Three-phase packed distillation has been so far relatively poorly understood. Hence, a substantial mass transfer model describing the (vapor−liquid−liquid) three-phase flow in packed column is proposed to explore the essence of three-phase distillation. The model enables, for the first time, rigorous computation of all the interphase transfer parameters on the basis of a thorough consideration of the unique flow behaviors (such as film breakup, rivulet-flow, surface variation, etc.) caused by the second liquid. The derived theoretical mass transfer model has been incorporated into the three-phase nonequilibrium simulation. Moreover, comprehensive experimental investigations have been carried out using two laboratory-scale columns, and four different packings (Montz-Pak B1-350, Rombopak 9M, Raschig Super-Ring 0.3, and Sulzer Optiflow C.36) were considered. The derived experimental database, covering a wide range of load conditions, is used for flow pattern identification and model validation. For the studied n-butanol/water/n-propanol system, it is revealed that the flow pattern of the second liquid (aqueous phase) could play a critical role in the system performance. When the second liquid flows below the first liquid film, it will enlarge the interfacial area and enhance the vapor−liquid mass transfer; when the second liquid flows above the first liquid film, it will reduce the interfacial area and degrade the mass transfer. This fundamental flow behavior may essentially result in the discrepancy existing in the highly variable separation efficiencies in three-phase packed columns. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9010645 [article] Exploring the essence of three-phase packed distillation : substantial mass transfer computation [texte imprimé] / Chen, Liang, Auteur ; Jens-Uwe Repke, Auteur ; Günter Wozny, Auteur . - 2010 . - pp 822–837. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 822–837 Mots-clés : Essence  Mass  transfer  Vapor  Liquid. Résumé : Three-phase packed distillation has been so far relatively poorly understood. Hence, a substantial mass transfer model describing the (vapor−liquid−liquid) three-phase flow in packed column is proposed to explore the essence of three-phase distillation. The model enables, for the first time, rigorous computation of all the interphase transfer parameters on the basis of a thorough consideration of the unique flow behaviors (such as film breakup, rivulet-flow, surface variation, etc.) caused by the second liquid. The derived theoretical mass transfer model has been incorporated into the three-phase nonequilibrium simulation. Moreover, comprehensive experimental investigations have been carried out using two laboratory-scale columns, and four different packings (Montz-Pak B1-350, Rombopak 9M, Raschig Super-Ring 0.3, and Sulzer Optiflow C.36) were considered. The derived experimental database, covering a wide range of load conditions, is used for flow pattern identification and model validation. For the studied n-butanol/water/n-propanol system, it is revealed that the flow pattern of the second liquid (aqueous phase) could play a critical role in the system performance. When the second liquid flows below the first liquid film, it will enlarge the interfacial area and enhance the vapor−liquid mass transfer; when the second liquid flows above the first liquid film, it will reduce the interfacial area and degrade the mass transfer. This fundamental flow behavior may essentially result in the discrepancy existing in the highly variable separation efficiencies in three-phase packed columns. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9010645

Extension of the mass transfer calculation for three-phase distillation in a packed column / Chen, Liang in Industrial & engineering chemistry research, Vol. 48 N° 15 (Août 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 15 (Août 2009) . - pp. 7289–7300 Titre : Extension of the mass transfer calculation for three-phase distillation in a packed column : nonequilibrium model based parameter estimation Type de document : texte imprimé Auteurs : Chen, Liang, Auteur ; Jens-Uwe Repke, Auteur ; Günter Wozny, Auteur Année de publication : 2009 Article en page(s) : pp. 7289–7300 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Nonequilibrium  modeling  Three-phase  distillation  Packed  column Résumé : Nonequilibrium (NEQ) modeling of three-phase (vapor−liquid−liquid) distillation in a packed column is still lacking of reliable correlations to calculate the interphase rate-based mass transfer. In this paper, extensions of the two most-used correlations [i.e., the Rocha correlation (Rocha, J. A.; Bravo, J. L.; Fair, J. R. Distillation Columns Containing Structured Packings: A Comprehensive Model for Their Performance. 2. Mass-Transfer Model. Ind. Eng. Chem. Res. 1996, 35, 1660) and the Billet and Schultes correlation (Billet, R.; Schultes, M. Prediction of Mass Transfer Columns with Dumped and Arranged Packings: Updated Summary of the Calculation Method of Billet & Schultes. Chem. Eng. Res. Des. 1999, 77, 498)] are proposed for mass transfer calculation of three-phase distillation in a packed column. Parameters used in the correlations are estimated on the basis of comprehensive experimental investigations on both two-phase (vapor−liquid) and three-phase distillation. The experimental database contains 150 different experiments of the 1-butanol/water/1-propanol system for different packings (Montz-Pak B1-350, Raschig Super-Ring 0.3, Rombopak 9M). The parameter estimation with multiple data sets and multipacking turns out to be a large-scale optimization problem subjected to a large number of nonlinear model equations. To reduce the problem dimension and remove coupling among the parameters, a hierarchical estimation strategy is proposed. The parameters are classified into packing-related and flow-related parameters, which are estimated using two-phase and three-phase distillation experimental data, respectively. In this way, the extension of mass transfer calculation for three-phase distillation is derived. Substantial improvements in the NEQ model prediction have been achieved. Compared with two-phase distillation, an increase of overall mass transfer ability is observed for the studied three-phase system. The extension of the mass transfer calculation can give a reasonable explanation for this observation, providing a better understanding of the intrinsic transfer phenomena inside three-phase packed columns. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900404p [article] Extension of the mass transfer calculation for three-phase distillation in a packed column : nonequilibrium model based parameter estimation [texte imprimé] / Chen, Liang, Auteur ; Jens-Uwe Repke, Auteur ; Günter Wozny, Auteur . - 2009 . - pp. 7289–7300. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 15 (Août 2009) . - pp. 7289–7300 Mots-clés : Nonequilibrium  modeling  Three-phase  distillation  Packed  column Résumé : Nonequilibrium (NEQ) modeling of three-phase (vapor−liquid−liquid) distillation in a packed column is still lacking of reliable correlations to calculate the interphase rate-based mass transfer. In this paper, extensions of the two most-used correlations [i.e., the Rocha correlation (Rocha, J. A.; Bravo, J. L.; Fair, J. R. Distillation Columns Containing Structured Packings: A Comprehensive Model for Their Performance. 2. Mass-Transfer Model. Ind. Eng. Chem. Res. 1996, 35, 1660) and the Billet and Schultes correlation (Billet, R.; Schultes, M. Prediction of Mass Transfer Columns with Dumped and Arranged Packings: Updated Summary of the Calculation Method of Billet & Schultes. Chem. Eng. Res. Des. 1999, 77, 498)] are proposed for mass transfer calculation of three-phase distillation in a packed column. Parameters used in the correlations are estimated on the basis of comprehensive experimental investigations on both two-phase (vapor−liquid) and three-phase distillation. The experimental database contains 150 different experiments of the 1-butanol/water/1-propanol system for different packings (Montz-Pak B1-350, Raschig Super-Ring 0.3, Rombopak 9M). The parameter estimation with multiple data sets and multipacking turns out to be a large-scale optimization problem subjected to a large number of nonlinear model equations. To reduce the problem dimension and remove coupling among the parameters, a hierarchical estimation strategy is proposed. The parameters are classified into packing-related and flow-related parameters, which are estimated using two-phase and three-phase distillation experimental data, respectively. In this way, the extension of mass transfer calculation for three-phase distillation is derived. Substantial improvements in the NEQ model prediction have been achieved. Compared with two-phase distillation, an increase of overall mass transfer ability is observed for the studied three-phase system. The extension of the mass transfer calculation can give a reasonable explanation for this observation, providing a better understanding of the intrinsic transfer phenomena inside three-phase packed columns. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900404p

Handling uncertainty in model-based optimal experimental design / Tilman Barz in Industrial & engineering chemistry research, Vol. 49 N° 12 (Juin 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5702–5713 Titre : Handling uncertainty in model-based optimal experimental design Type de document : texte imprimé Auteurs : Tilman Barz, Auteur ; Harvey Arellano-Garcia, Auteur ; Günter Wozny, Auteur Année de publication : 2010 Article en page(s) : pp. 5702–5713 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Uncertainties  Protein  ion-exchange  equilibrium  parameters Résumé : In contrast to the majority of published works in the field of model-based optimal experimental design which focused on numerical studies so as to demonstrate the validity of the OED approach or the development of new criteria or numerical approaches, this work is mainly concerned with the experimental application and practical insights gained from the adaption of an optimal design framework. The presented work is discussed based on the determination of protein ion-exchange equilibrium parameters. For this purpose, special attention is paid to the explicit modeling of all laboratory steps so as to prepare, implement, and analyze experiments in order to have a realistic definition of the numeric design problem and to formally include experimental restrictions and sources of uncertainties in the problem formulation. Moreover, whereas the effect of erroneous assumptions in the initially assumed parameter values have been covered by various authors, in this work, uncertainties are considered in a more general way including those which arise during an imprecise implementation of optimal planned experiments. To compensate for uncertainty influences, a feed-back based approach to optimal design is adopted based on the combination of the parallel and sequential design approaches. Uncertainty identification is done by solution of an augmented parameter estimation problem, where deviations in the experimental design are detected and estimated together with the parameter values. It has been shown that uncertainty influences vanish along with the iterative refinement of the experiment design variables and estimated parameter values. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901611b [article] Handling uncertainty in model-based optimal experimental design [texte imprimé] / Tilman Barz, Auteur ; Harvey Arellano-Garcia, Auteur ; Günter Wozny, Auteur . - 2010 . - pp. 5702–5713. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5702–5713 Mots-clés : Uncertainties  Protein  ion-exchange  equilibrium  parameters Résumé : In contrast to the majority of published works in the field of model-based optimal experimental design which focused on numerical studies so as to demonstrate the validity of the OED approach or the development of new criteria or numerical approaches, this work is mainly concerned with the experimental application and practical insights gained from the adaption of an optimal design framework. The presented work is discussed based on the determination of protein ion-exchange equilibrium parameters. For this purpose, special attention is paid to the explicit modeling of all laboratory steps so as to prepare, implement, and analyze experiments in order to have a realistic definition of the numeric design problem and to formally include experimental restrictions and sources of uncertainties in the problem formulation. Moreover, whereas the effect of erroneous assumptions in the initially assumed parameter values have been covered by various authors, in this work, uncertainties are considered in a more general way including those which arise during an imprecise implementation of optimal planned experiments. To compensate for uncertainty influences, a feed-back based approach to optimal design is adopted based on the combination of the parallel and sequential design approaches. Uncertainty identification is done by solution of an augmented parameter estimation problem, where deviations in the experimental design are detected and estimated together with the parameter values. It has been shown that uncertainty influences vanish along with the iterative refinement of the experiment design variables and estimated parameter values. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901611b

Local optima in model - based optimal experimental design / Jan C. Schoneberger in Industrial & engineering chemistry research, Vol. 49 N° 20 (Octobre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10059–10073 Titre : Local optima in model - based optimal experimental design Type de document : texte imprimé Auteurs : Jan C. Schoneberger, Auteur ; Harvey Arellano-Garcia, Auteur ; Günter Wozny, Auteur Année de publication : 2011 Article en page(s) : pp. 10059–10073 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Optimal Résumé : Model-based nonlinear optimal experimental design (OED) has advanced to a relevant systematic tool in model development. However, the high nonlinearity of OED problems and their required high computational effort makes the optimization a challenging task. The objective of this work is to point out a crucial aspect of OED problems, namely, the existence of local minima. For this purpose, general characteristics of OED problems are presented and discussed, using different OED criteria and approaches (sequential/parallel). Furthermore, five different approaches are compared to overcome the local minima problem. Tuning options to improve the computation time of hybrid approaches are derived and discussed. The approaches are compared, based on the results of two case studies. To solve high-dimensional complex OED problems, a proposed hybrid framework is found to be a promising approach. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9016094 [article] Local optima in model - based optimal experimental design [texte imprimé] / Jan C. Schoneberger, Auteur ; Harvey Arellano-Garcia, Auteur ; Günter Wozny, Auteur . - 2011 . - pp. 10059–10073. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10059–10073 Mots-clés : Optimal Résumé : Model-based nonlinear optimal experimental design (OED) has advanced to a relevant systematic tool in model development. However, the high nonlinearity of OED problems and their required high computational effort makes the optimization a challenging task. The objective of this work is to point out a crucial aspect of OED problems, namely, the existence of local minima. For this purpose, general characteristics of OED problems are presented and discussed, using different OED criteria and approaches (sequential/parallel). Furthermore, five different approaches are compared to overcome the local minima problem. Tuning options to improve the computation time of hybrid approaches are derived and discussed. The approaches are compared, based on the results of two case studies. To solve high-dimensional complex OED problems, a proposed hybrid framework is found to be a promising approach. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9016094

Model-based experimental analysis of a fixed-bed reactor for catalytic SO2 oxidation / J. C. Schöneberger in Industrial & engineering chemistry research, Vol. 48 N° 11 (Juin 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5165–5176 Titre : Model-based experimental analysis of a fixed-bed reactor for catalytic SO2 oxidation Type de document : texte imprimé Auteurs : J. C. Schöneberger, Auteur ; H. Arellano-Garcia, Auteur ; Günter Wozny, Auteur Année de publication : 2009 Article en page(s) : pp. 5165–5176 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Nonlinear  experimental  design  Kinetic  models Résumé : In this work, a systematic approach based on nonlinear experimental design as an efficient tool for the validation of kinetic models is proposed which has the objective of computing experimental layouts, setups, and controls in order to optimize the statistical reliability of parameter estimates from the resulting experimental data. Furthermore, because the optimum experimental design is dependent on the values of the parameters, a sequential design is proposed. This represents an interaction between proposed experiments (e.g., inlet temperature and concentration), their evaluation, parameter estimation, and new design information such as reactor layout, sampling points, and temperature measurement positions. This follows an iterative procedure until all parameters achieve a prescribed statistical quality. Because of the fact that the overlaying optimization problem contains a highly nonlinear objective function, a hybrid optimization framework is also proposed to overcome the problem of local minima. To show the efficiency of the developed framework, it has been applied to the contact reaction. This reaction is a basic step in the sulfuric acid production and is carried out in a catalytic fixed-bed reactor called the contact horde. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801288d [article] Model-based experimental analysis of a fixed-bed reactor for catalytic SO2 oxidation [texte imprimé] / J. C. Schöneberger, Auteur ; H. Arellano-Garcia, Auteur ; Günter Wozny, Auteur . - 2009 . - pp. 5165–5176. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5165–5176 Mots-clés : Nonlinear  experimental  design  Kinetic  models Résumé : In this work, a systematic approach based on nonlinear experimental design as an efficient tool for the validation of kinetic models is proposed which has the objective of computing experimental layouts, setups, and controls in order to optimize the statistical reliability of parameter estimates from the resulting experimental data. Furthermore, because the optimum experimental design is dependent on the values of the parameters, a sequential design is proposed. This represents an interaction between proposed experiments (e.g., inlet temperature and concentration), their evaluation, parameter estimation, and new design information such as reactor layout, sampling points, and temperature measurement positions. This follows an iterative procedure until all parameters achieve a prescribed statistical quality. Because of the fact that the overlaying optimization problem contains a highly nonlinear objective function, a hybrid optimization framework is also proposed to overcome the problem of local minima. To show the efficiency of the developed framework, it has been applied to the contact reaction. This reaction is a basic step in the sulfuric acid production and is carried out in a catalytic fixed-bed reactor called the contact horde. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801288d

A modular approach to sustainability assessment and decision support in chemical process design / Mohamad R. Othman in Industrial & engineering chemistry research, Vol. 49 N° 17 (Septembre 1, 2010) 

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Robust implementation of optimal decisions using a two-layer chance-constrained approach / Tilman Barz in Industrial & engineering chemistry research, Vol. 50 N° 9 (Mai 2011) 

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