Documents disponibles écrits par cet auteur

Integrated design and control using a simultaneous mixed-integer dynamic optimization approach / Rodrigo López-Negrete de la Fuente in Industrial & engineering chemistry research, Vol. 48 N°4 (Février 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1933–1943 Titre : Integrated design and control using a simultaneous mixed-integer dynamic optimization approach Type de document : texte imprimé Auteurs : Rodrigo López-Negrete de la Fuente, Auteur ; Antonio Flores-Tlacuahuac, Auteur Année de publication : 2009 Article en page(s) : pp. 1933–1943 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Binary  distillation  column  Mixed-integer  nonlinear  programming  Dynamic  optimization  approach Résumé : In this work, we address the simultaneous design and control of a binary distillation column. The problem is first formulated as a mixed-integer dynamic optimization problem that is then transformed into a mixed-integer nonlinear programming problem using the simultaneous dynamic optimization approach (i.e., full discretization). This formulation is capable of designing the optimal feed tray location, tray sizing, optimal operating steady states, the optimal open-loop trajectory between them, and also the best controller paring and parameters that does the best tracking of the open-loop trajectory. For solving the complex mixed-integer dynamic optimization problem, an optimization decomposition strategy is proposed. The solution strategy is based on solving relaxed versions of the optimization problem and using the results to initialize complex problem versions. The full space problem was solved with the Bonmin solver. Two cases were analyzed, and in both the solver and the proposed decomposition strategy were capable of solving the problems successfully. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801353c [article] Integrated design and control using a simultaneous mixed-integer dynamic optimization approach [texte imprimé] / Rodrigo López-Negrete de la Fuente, Auteur ; Antonio Flores-Tlacuahuac, Auteur . - 2009 . - pp. 1933–1943. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1933–1943 Mots-clés : Binary  distillation  column  Mixed-integer  nonlinear  programming  Dynamic  optimization  approach Résumé : In this work, we address the simultaneous design and control of a binary distillation column. The problem is first formulated as a mixed-integer dynamic optimization problem that is then transformed into a mixed-integer nonlinear programming problem using the simultaneous dynamic optimization approach (i.e., full discretization). This formulation is capable of designing the optimal feed tray location, tray sizing, optimal operating steady states, the optimal open-loop trajectory between them, and also the best controller paring and parameters that does the best tracking of the open-loop trajectory. For solving the complex mixed-integer dynamic optimization problem, an optimization decomposition strategy is proposed. The solution strategy is based on solving relaxed versions of the optimization problem and using the results to initialize complex problem versions. The full space problem was solved with the Bonmin solver. Two cases were analyzed, and in both the solver and the proposed decomposition strategy were capable of solving the problems successfully. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801353c

Multiobjective nonlinear model predictive control of a class of chemical reactors / Antonio Flores-Tlacuahuac in Industrial & engineering chemistry research, Vol. 51 N° 17 (Mai 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 17 (Mai 2012) . - pp. 5891–5899 Titre : Multiobjective nonlinear model predictive control of a class of chemical reactors Type de document : texte imprimé Auteurs : Antonio Flores-Tlacuahuac, Auteur ; Pilar Morales, Auteur ; Martin Rivera-Toledo, Auteur Année de publication : 2012 Article en page(s) : pp. 5891–5899 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Chemical  reactors  Optimization Résumé : Many problems in science and engineering can be posed as multiobjective optimization problems where several objectives must be met simultaneously. Commonly such multiobjective optimization problems are reduced to a single optimization problem by merging all the involved objective functions by using rather subjective weighting functions. This solution procedure can produce suboptimal solutions, and it is not a systematic method since the choice of the weighting functions is up to the designer. Process control is one of the engineering fields where multiobjective optimization control problems frequently emerge because such problems normally involve conflicting objective functions such as economical profit and environmental concerns. Because the optimal value of the conflicting objective functions cannot be simultaneously achieved one has to compute a trade-off solution that best suits, in a given sense, all the objective functions. Moreover, additional requirements, beyond upset rejection and set-point tracking, such as the determination of optimal operating conditions should also be handled by dynamic real time optimal control approaches. In this work we propose a novel multiobjective optimization and control approach able to get target points while simultaneously computing optimal operating conditions. The proposed approach can be applied to nonlinear dynamic systems and does not require the specification of arbitrary weighting functions to handle conflicting multiobjective optimization problems. Several case studies using chemical reactors of varying nonlinear behavior are deployed to illustrate the practical application of the proposed dynamic real time optimization approach. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201742e [article] Multiobjective nonlinear model predictive control of a class of chemical reactors [texte imprimé] / Antonio Flores-Tlacuahuac, Auteur ; Pilar Morales, Auteur ; Martin Rivera-Toledo, Auteur . - 2012 . - pp. 5891–5899. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 17 (Mai 2012) . - pp. 5891–5899 Mots-clés : Chemical  reactors  Optimization Résumé : Many problems in science and engineering can be posed as multiobjective optimization problems where several objectives must be met simultaneously. Commonly such multiobjective optimization problems are reduced to a single optimization problem by merging all the involved objective functions by using rather subjective weighting functions. This solution procedure can produce suboptimal solutions, and it is not a systematic method since the choice of the weighting functions is up to the designer. Process control is one of the engineering fields where multiobjective optimization control problems frequently emerge because such problems normally involve conflicting objective functions such as economical profit and environmental concerns. Because the optimal value of the conflicting objective functions cannot be simultaneously achieved one has to compute a trade-off solution that best suits, in a given sense, all the objective functions. Moreover, additional requirements, beyond upset rejection and set-point tracking, such as the determination of optimal operating conditions should also be handled by dynamic real time optimal control approaches. In this work we propose a novel multiobjective optimization and control approach able to get target points while simultaneously computing optimal operating conditions. The proposed approach can be applied to nonlinear dynamic systems and does not require the specification of arbitrary weighting functions to handle conflicting multiobjective optimization problems. Several case studies using chemical reactors of varying nonlinear behavior are deployed to illustrate the practical application of the proposed dynamic real time optimization approach. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201742e

A multiobjective optimization approach for the simultaneous single line scheduling and control of CSTRs / Miguel Angel Gutiérrez-Limon in Industrial & engineering chemistry research, Vol. 51 N° 17 (Mai 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 17 (Mai 2012) . - pp. 5881–5890 Titre : A multiobjective optimization approach for the simultaneous single line scheduling and control of CSTRs Type de document : texte imprimé Auteurs : Miguel Angel Gutiérrez-Limon, Auteur ; Antonio Flores-Tlacuahuac, Auteur ; Ignacio E. Grossmann, Auteur Année de publication : 2012 Article en page(s) : pp. 5881–5890 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Optimization  Process  dynamic Résumé : A new multiobjective optimization formulation dealing with simultaneous scheduling and control issues in single line processing systems is proposed. Objective functions featuring economic profit and dynamic performance are considered because normally they are in conflict. Because integer, continuous variables and process dynamic behavior are involved, the bicriterion optimization problem is cast in terms of a mixed-integer dynamic optimization (MIDO) problem. The Pareto front of each problem is computed using the ε-constraint method for handling multiobjective problems. The results indicate that improved optimal solutions can be obtained by using multiobjective optimization techniques instead of just simple merging of all the target objective functions into a single objective. The proposed multiobjective approach for handling scheduling and control problems is illustrated using three CSTR examples of varying nonlinear behavior. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201740s [article] A multiobjective optimization approach for the simultaneous single line scheduling and control of CSTRs [texte imprimé] / Miguel Angel Gutiérrez-Limon, Auteur ; Antonio Flores-Tlacuahuac, Auteur ; Ignacio E. Grossmann, Auteur . - 2012 . - pp. 5881–5890. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 17 (Mai 2012) . - pp. 5881–5890 Mots-clés : Optimization  Process  dynamic Résumé : A new multiobjective optimization formulation dealing with simultaneous scheduling and control issues in single line processing systems is proposed. Objective functions featuring economic profit and dynamic performance are considered because normally they are in conflict. Because integer, continuous variables and process dynamic behavior are involved, the bicriterion optimization problem is cast in terms of a mixed-integer dynamic optimization (MIDO) problem. The Pareto front of each problem is computed using the ε-constraint method for handling multiobjective problems. The results indicate that improved optimal solutions can be obtained by using multiobjective optimization techniques instead of just simple merging of all the target objective functions into a single objective. The proposed multiobjective approach for handling scheduling and control problems is illustrated using three CSTR examples of varying nonlinear behavior. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201740s

Optimal molecular design of ionic liquids for high-purity bioethanol production / Luz María Chávez-Islas in Industrial & engineering chemistry research, Vol. 50 N° 9 (Mai 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 9 (Mai 2011) . - pp. 5153-5168 Titre : Optimal molecular design of ionic liquids for high-purity bioethanol production Type de document : texte imprimé Auteurs : Luz María Chávez-Islas, Auteur ; Ruben Vasquez-Medrano, Auteur ; Antonio Flores-Tlacuahuac, Auteur Année de publication : 2011 Article en page(s) : pp. 5153-5168 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Production  High  purity  Ionic  liquid  Design Résumé : A mixed-integer nonlinear programming (MINLP) formulation for the molecular design optimization of ionic liquids (ILs) to recuperate ethanol with a purity of 99 mol % or greater from a E85 system (a mixture containing 85 and 15 mol% of ethanol and water, respectively) is presented. The reason why the ethanol/water separation is difficult is because of the azeotropic behavior of this system. Therefore, the IL is designed to feature water affinity such that it can break the ethanol/water azeotrope, allowing the high-purity separation to take place. The MINLP formulation is based on the development of a superstructure that contains a set of cations and anions, whose combination forms different kinds of ILs that have the potential to separate azeotropic systems such as the ethanol/water system. Because most of the ILs to be optimally designed are novel solvents, their physical and thermodynamic properties are estimated by group contribution methods. The optimization formulation is composed of a set of constraints featuring vapor―liquid equilibrium conditions as well as constraints dealing with structural and allowed cation-anion combinations. We assume that the separation will take place at atmospheric pressure. For the sake of simplicity, the optimal IL is first synthesized in a single separation stage, although the separation was also addressed using a reboiled absorption column. The results indicate that the optimally designed IL is capable of performing the required separation meeting the high-purity ethanol constraint. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24128639 [article] Optimal molecular design of ionic liquids for high-purity bioethanol production [texte imprimé] / Luz María Chávez-Islas, Auteur ; Ruben Vasquez-Medrano, Auteur ; Antonio Flores-Tlacuahuac, Auteur . - 2011 . - pp. 5153-5168. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 9 (Mai 2011) . - pp. 5153-5168 Mots-clés : Production  High  purity  Ionic  liquid  Design Résumé : A mixed-integer nonlinear programming (MINLP) formulation for the molecular design optimization of ionic liquids (ILs) to recuperate ethanol with a purity of 99 mol % or greater from a E85 system (a mixture containing 85 and 15 mol% of ethanol and water, respectively) is presented. The reason why the ethanol/water separation is difficult is because of the azeotropic behavior of this system. Therefore, the IL is designed to feature water affinity such that it can break the ethanol/water azeotrope, allowing the high-purity separation to take place. The MINLP formulation is based on the development of a superstructure that contains a set of cations and anions, whose combination forms different kinds of ILs that have the potential to separate azeotropic systems such as the ethanol/water system. Because most of the ILs to be optimally designed are novel solvents, their physical and thermodynamic properties are estimated by group contribution methods. The optimization formulation is composed of a set of constraints featuring vapor―liquid equilibrium conditions as well as constraints dealing with structural and allowed cation-anion combinations. We assume that the separation will take place at atmospheric pressure. For the sake of simplicity, the optimal IL is first synthesized in a single separation stage, although the separation was also addressed using a reboiled absorption column. The results indicate that the optimally designed IL is capable of performing the required separation meeting the high-purity ethanol constraint. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24128639

Optimal synthesis of a high purity bioethanol distillation column using ionic liquids / Luz María Chávez-Islas in Industrial & engineering chemistry research, Vol. 50 N° 9 (Mai 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 9 (Mai 2011) . - pp. 5175-5190 Titre : Optimal synthesis of a high purity bioethanol distillation column using ionic liquids Type de document : texte imprimé Auteurs : Luz María Chávez-Islas, Auteur ; Ruben Vasquez-Medrano, Auteur ; Antonio Flores-Tlacuahuac, Auteur Année de publication : 2011 Article en page(s) : pp. 5175-5190 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ionic  liquid  Distillation  column  High  purity  Optimal  design Résumé : In this work, we address the optimal economical synthesis of an extractive distillation column for bioethanol purification, using ionic liquids as a type of solvent that can be designed to feature sustainable characteristics, such as low toxicity and low volatility, among other desirable properties. For the optimal synthesis of the separation scheme, we propose a mixed-integer nonlinear programming (MINLP) formulation, merged with disjunctive programming tools, to take care of modeling logical decisions [Yeomans and Grossmann, Ind. Eng. Chem. Res. 2000, 39, 1637―1648]. In a previous work [Chavez-Islas et al., submitted to Ind. Eng. Chem. Res.], we have addressed the design of a novel ionic liquid to separate the ethanol/water azeotropic system, up to high purities. The MLNLP synthesis of the distillation column considers the feed tray location, the number of trays, and the operating and design parameters as decision variables. Because the ionic liquid used in this work is a novel solvent, its physical and thermodynamic properties are yet not available. Therefore, the physical properties of the ionic liquid are estimated using group contribution methods. The MINLP formulation is based on the application of the MESH equations for conditional trays, to reduce the size of the nonlinear subproblems and increase the robustness of the optimization formulation. The MINLP problem was solved using the SBB solver embedded in GAMS. Using the proposed MINLP formulation, we attained ethanol purities as good as 99.9 mol %, and 90% of the ethanol presented in the feed stream was recovered. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24128641 [article] Optimal synthesis of a high purity bioethanol distillation column using ionic liquids [texte imprimé] / Luz María Chávez-Islas, Auteur ; Ruben Vasquez-Medrano, Auteur ; Antonio Flores-Tlacuahuac, Auteur . - 2011 . - pp. 5175-5190. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 9 (Mai 2011) . - pp. 5175-5190 Mots-clés : Ionic  liquid  Distillation  column  High  purity  Optimal  design Résumé : In this work, we address the optimal economical synthesis of an extractive distillation column for bioethanol purification, using ionic liquids as a type of solvent that can be designed to feature sustainable characteristics, such as low toxicity and low volatility, among other desirable properties. For the optimal synthesis of the separation scheme, we propose a mixed-integer nonlinear programming (MINLP) formulation, merged with disjunctive programming tools, to take care of modeling logical decisions [Yeomans and Grossmann, Ind. Eng. Chem. Res. 2000, 39, 1637―1648]. In a previous work [Chavez-Islas et al., submitted to Ind. Eng. Chem. Res.], we have addressed the design of a novel ionic liquid to separate the ethanol/water azeotropic system, up to high purities. The MLNLP synthesis of the distillation column considers the feed tray location, the number of trays, and the operating and design parameters as decision variables. Because the ionic liquid used in this work is a novel solvent, its physical and thermodynamic properties are yet not available. Therefore, the physical properties of the ionic liquid are estimated using group contribution methods. The MINLP formulation is based on the application of the MESH equations for conditional trays, to reduce the size of the nonlinear subproblems and increase the robustness of the optimization formulation. The MINLP problem was solved using the SBB solver embedded in GAMS. Using the proposed MINLP formulation, we attained ethanol purities as good as 99.9 mol %, and 90% of the ethanol presented in the feed stream was recovered. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24128641

Simultaneous cyclic scheduling and control of tubular reactors / Antonio Flores-Tlacuahuac in Industrial & engineering chemistry research, Vol. 50 N° 13 (Juillet 2011) 

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Simultaneous cyclic scheduling and control of tubular reactors / Antonio Flores-Tlacuahuac in Industrial & engineering chemistry research, Vol. 49 N° 22 (Novembre 2010) 

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Simultaneous optimal design of an extractive column and ionic liquid for the separation of bioethanol – water mixtures / Darinel Valencia-Marquez in Industrial & engineering chemistry research, Vol. 51 N° 17 (Mai 2012) 

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Simultaneous scheduling and control of multiproduct continuous parallel lines / Antonio Flores-Tlacuahuac in Industrial & engineering chemistry research, Vol. 49 N° 17 (Septembre 1, 2010) 

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