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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

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) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7870–7881 Titre : A modular approach to sustainability assessment and decision support in chemical process design Type de document : texte imprimé Auteurs : Mohamad R. Othman, Auteur ; Jens-Uwe Repke, Auteur ; Günter Wozny, Auteur Année de publication : 2010 Article en page(s) : pp 7870–7881 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Chemical  process  design. Résumé : In chemical and allied industries, process design sustainability has gained public concern in academia, industry, government agencies, and social groups. Over the past decade, a variety of sustainability indicators have been introduced, but with various challenges in application. It becomes clear that the industries need urgently practical tools for conducting systematic sustainability assessment on existing processes and/or new designs and, further, for helping derive the most desirable design decisions. This paper presents a systematic, general approach for sustainability assessment and design selection through integrating hard (quantitative) economic and environmental indicators along with soft (qualitative) indicators for social criteria into design activities. The approach contains four modules: a process simulator module, an equipment and inventory acquisition module, a sustainability assessment module, and a decision support module. The modules fully utilize and extend the capabilities of the process simulator Aspen Plus, Aspen Simulation Workbook, and a spreadsheet, where case model development, data acquisition and analysis, team contribution assessment, and decision support are effectively integrated. The efficacy of the introduced approach is illustrated by the example of biodiesel process design, where insightful sustainability analysis and persuasive decision support show its superiority over commonly practiced technoeconomy evaluation approaches. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901943d [article] A modular approach to sustainability assessment and decision support in chemical process design [texte imprimé] / Mohamad R. Othman, Auteur ; Jens-Uwe Repke, Auteur ; Günter Wozny, Auteur . - 2010 . - pp 7870–7881. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7870–7881 Mots-clés : Chemical  process  design. Résumé : In chemical and allied industries, process design sustainability has gained public concern in academia, industry, government agencies, and social groups. Over the past decade, a variety of sustainability indicators have been introduced, but with various challenges in application. It becomes clear that the industries need urgently practical tools for conducting systematic sustainability assessment on existing processes and/or new designs and, further, for helping derive the most desirable design decisions. This paper presents a systematic, general approach for sustainability assessment and design selection through integrating hard (quantitative) economic and environmental indicators along with soft (qualitative) indicators for social criteria into design activities. The approach contains four modules: a process simulator module, an equipment and inventory acquisition module, a sustainability assessment module, and a decision support module. The modules fully utilize and extend the capabilities of the process simulator Aspen Plus, Aspen Simulation Workbook, and a spreadsheet, where case model development, data acquisition and analysis, team contribution assessment, and decision support are effectively integrated. The efficacy of the introduced approach is illustrated by the example of biodiesel process design, where insightful sustainability analysis and persuasive decision support show its superiority over commonly practiced technoeconomy evaluation approaches. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901943d

Reduction of energy consumption in the process industry using a heat-integrated hybrid distillation pervaporation process / Maria T. Del Pozo Gomez in Industrial & engineering chemistry research, Vol. 48 N° 9 (Mai 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 9 (Mai 2009) . - pp. 4484–4494 Titre : Reduction of energy consumption in the process industry using a heat-integrated hybrid distillation pervaporation process Type de document : texte imprimé Auteurs : Maria T. Del Pozo Gomez, Auteur ; Jens-Uwe Repke, Auteur ; Deu-yeun Kim, Auteur Année de publication : 2009 Article en page(s) : pp. 4484–4494 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hybrid  distillation  pervaporation  process  Heat  integration  Condensation  energy Résumé : In the present work, the advantages of using heat integration in a hybrid distillation pervaporation process are studied and, on the basis of the developed model, the industrial applicability of the process is analyzed. The basic idea of the heat integration is to condense the distillate stream in a heat-exchanger pipe inside the membrane. The condensation energy is directly released into the process, not needing external heat exchangers to preheat the membrane feed. This is reflected in an important reduction in the process energy consumption. Experimental work has been carried out in order to characterize the membrane and to prove the positive influence of the heat integration. A rigorous model for the pervaporation process has been developed and validated. Additionally, simulation studies take place in order to compare the energy supply in the proposed process with a typical industrial process layout. As a result, in comparison to the results of Sommer and Melin [Sommer, S; Melin, T. Ind. Eng. Chem. Res. 2004, 43, 5248−5259], energy savings of 44.7% can be achieved. Further study has been realized in order to prove the reduction in the specific separation costs. The operation conditions have been varied, finding always lower specific separation costs in the heat integrated case. In the optimal operation point, the reduction reaches its maximum value of 20%. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801540a [article] Reduction of energy consumption in the process industry using a heat-integrated hybrid distillation pervaporation process [texte imprimé] / Maria T. Del Pozo Gomez, Auteur ; Jens-Uwe Repke, Auteur ; Deu-yeun Kim, Auteur . - 2009 . - pp. 4484–4494. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 9 (Mai 2009) . - pp. 4484–4494 Mots-clés : Hybrid  distillation  pervaporation  process  Heat  integration  Condensation  energy Résumé : In the present work, the advantages of using heat integration in a hybrid distillation pervaporation process are studied and, on the basis of the developed model, the industrial applicability of the process is analyzed. The basic idea of the heat integration is to condense the distillate stream in a heat-exchanger pipe inside the membrane. The condensation energy is directly released into the process, not needing external heat exchangers to preheat the membrane feed. This is reflected in an important reduction in the process energy consumption. Experimental work has been carried out in order to characterize the membrane and to prove the positive influence of the heat integration. A rigorous model for the pervaporation process has been developed and validated. Additionally, simulation studies take place in order to compare the energy supply in the proposed process with a typical industrial process layout. As a result, in comparison to the results of Sommer and Melin [Sommer, S; Melin, T. Ind. Eng. Chem. Res. 2004, 43, 5248−5259], energy savings of 44.7% can be achieved. Further study has been realized in order to prove the reduction in the specific separation costs. The operation conditions have been varied, finding always lower specific separation costs in the heat integrated case. In the optimal operation point, the reduction reaches its maximum value of 20%. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801540a