Documents disponibles écrits par cet auteur

Development of a generalized mixed integer nonlinear programming model for assessing and improving the operational flexibility of water network designs / Chuei-Tin Chang in Industrial & engineering chemistry research, Vol. 48 N° 7 (Avril 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3496–3504 Titre : Development of a generalized mixed integer nonlinear programming model for assessing and improving the operational flexibility of water network designs Type de document : texte imprimé Auteurs : Chuei-Tin Chang, Auteur ; Bao-Hong Li, Auteur ; Chih-Wen Liou, Auteur Année de publication : 2009 Article en page(s) : pp. 3496–3504 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Water  network  Operational  flexibility  Mixed  integer  nonlinear  program Résumé : In designing and operating any water network, a typical issue that must be addressed is concerned with the uncertain process conditions. A systematic procedure is proposed in this paper to enhance the operational flexibility of a given structure. Specifically, two design options have been investigated: (1) relaxation of the allowed maximum freshwater consumption rate in the nominal design and (2) installation of auxiliary pipelines and/or elimination of existing ones. The flexibility index model proposed by Swaney and Grossmann (1985) has been modified and formulated in a generalized format to evaluate the impact of introducing various modifications into an existing network. Since this model is a mixed integer nonlinear program (MINLP), it is in general very difficult to locate the global optima in the iterative solution processes. A simple and effective initialization procedure has also been devised in this work to facilitate successful convergence. The effectiveness of the proposed approach is demonstrated with two examples in this paper. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8015363 [article] Development of a generalized mixed integer nonlinear programming model for assessing and improving the operational flexibility of water network designs [texte imprimé] / Chuei-Tin Chang, Auteur ; Bao-Hong Li, Auteur ; Chih-Wen Liou, Auteur . - 2009 . - pp. 3496–3504. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3496–3504 Mots-clés : Water  network  Operational  flexibility  Mixed  integer  nonlinear  program Résumé : In designing and operating any water network, a typical issue that must be addressed is concerned with the uncertain process conditions. A systematic procedure is proposed in this paper to enhance the operational flexibility of a given structure. Specifically, two design options have been investigated: (1) relaxation of the allowed maximum freshwater consumption rate in the nominal design and (2) installation of auxiliary pipelines and/or elimination of existing ones. The flexibility index model proposed by Swaney and Grossmann (1985) has been modified and formulated in a generalized format to evaluate the impact of introducing various modifications into an existing network. Since this model is a mixed integer nonlinear program (MINLP), it is in general very difficult to locate the global optima in the iterative solution processes. A simple and effective initialization procedure has also been devised in this work to facilitate successful convergence. The effectiveness of the proposed approach is demonstrated with two examples in this paper. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8015363

Efficient flexibility assessment procedure for water network designs / Bao-Hong Li in Industrial & engineering chemistry research, Vol. 50 N° 7 (Avril 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 7 (Avril 2011) . - pp. 3763–3774 Titre : Efficient flexibility assessment procedure for water network designs Type de document : texte imprimé Auteurs : Bao-Hong Li, Auteur ; Chuei-Tin Chang, Auteur Année de publication : 2011 Article en page(s) : pp. 3763–3774 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Water  network  designs Résumé : A new nonlinear programming (NLP) formulation of the conventional flexibility index model (Swaney and Grossmann, 1985) has been developed in this work for flexibility analysis of single-contaminant water networks. Since this improved model is constructed on the basis of a single critical point instead of the entire region of uncertain parameters, the iterative optimization process converges at a much faster rate. A systematic flexibility assessment procedure has also been devised to analyze and modify a given network so as to achieve the desired level of operational resiliency. Specific design steps are followed sequentially to check the feasibility of a nominal design and to improve its flexibility index by (1) relaxing the upper limit of freshwater capacity and/or (2) adding new pipelines and/or removing existing ones. The effectiveness of the proposed approach is demonstrated with two examples in this paper. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101329v [article] Efficient flexibility assessment procedure for water network designs [texte imprimé] / Bao-Hong Li, Auteur ; Chuei-Tin Chang, Auteur . - 2011 . - pp. 3763–3774. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 7 (Avril 2011) . - pp. 3763–3774 Mots-clés : Water  network  designs Résumé : A new nonlinear programming (NLP) formulation of the conventional flexibility index model (Swaney and Grossmann, 1985) has been developed in this work for flexibility analysis of single-contaminant water networks. Since this improved model is constructed on the basis of a single critical point instead of the entire region of uncertain parameters, the iterative optimization process converges at a much faster rate. A systematic flexibility assessment procedure has also been devised to analyze and modify a given network so as to achieve the desired level of operational resiliency. Specific design steps are followed sequentially to check the feasibility of a nominal design and to improve its flexibility index by (1) relaxing the upper limit of freshwater capacity and/or (2) adding new pipelines and/or removing existing ones. The effectiveness of the proposed approach is demonstrated with two examples in this paper. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101329v

A model-based search strategy for exhaustive identification of alternative water network designs / Bao-Hong Li in Industrial & engineering chemistry research, Vol. 50 N° 7 (Avril 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 7 (Avril 2011) . - pp.3653–3659 Titre : A model-based search strategy for exhaustive identification of alternative water network designs Type de document : texte imprimé Auteurs : Bao-Hong Li, Auteur Année de publication : 2011 Article en page(s) : pp.3653–3659 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Water  network  designs Résumé : A systematic procedure is proposed in this paper to identify all optimal single-contaminant water-using networks by solving a series of three mathematical programming models. In particular, a linear programming (LP) model is adopted in this procedure to minimize the operating costs incurred from freshwater consumption and wastewater treatment, and a mixed-integer linear program (MILP) is then utilized for minimizing the total number of interconnections in the network while keeping the total operating cost at its lowest level. The third model is also a MILP model, which is used to minimize the total throughput and generate all alternative designs under the conditions of fixed minimum operating costs and interconnection number. Notice that, since the nonlinear mass-balance constraints are all converted to linear form in the proposed models according to the necessary conditions of optimality (Savelski and Bagajewicz, 2000), the convergence of the corresponding optimization processes can always be guaranteed. The solution pool technique provided by the CPLEX II solver within GAMS environment has been adopted to search for all optima. Four examples are presented in this paper to demonstrate the effectiveness of the proposed approach. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100310g [article] A model-based search strategy for exhaustive identification of alternative water network designs [texte imprimé] / Bao-Hong Li, Auteur . - 2011 . - pp.3653–3659. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 7 (Avril 2011) . - pp.3653–3659 Mots-clés : Water  network  designs Résumé : A systematic procedure is proposed in this paper to identify all optimal single-contaminant water-using networks by solving a series of three mathematical programming models. In particular, a linear programming (LP) model is adopted in this procedure to minimize the operating costs incurred from freshwater consumption and wastewater treatment, and a mixed-integer linear program (MILP) is then utilized for minimizing the total number of interconnections in the network while keeping the total operating cost at its lowest level. The third model is also a MILP model, which is used to minimize the total throughput and generate all alternative designs under the conditions of fixed minimum operating costs and interconnection number. Notice that, since the nonlinear mass-balance constraints are all converted to linear form in the proposed models according to the necessary conditions of optimality (Savelski and Bagajewicz, 2000), the convergence of the corresponding optimization processes can always be guaranteed. The solution pool technique provided by the CPLEX II solver within GAMS environment has been adopted to search for all optima. Four examples are presented in this paper to demonstrate the effectiveness of the proposed approach. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100310g

Multiobjective optimization of water-using networks with multiple contaminants / Bao-Hong Li 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. 5651-5660 Titre : Multiobjective optimization of water-using networks with multiple contaminants Type de document : texte imprimé Auteurs : Bao-Hong Li, Auteur Année de publication : 2011 Article en page(s) : pp. 5651-5660 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Pollution  Optimization Résumé : A systematic multiobjective optimization procedure is developed in this study to produce realistic multicontaminant water-using network designs. In every given design problem, the most appropriate structure is identitied by solving three mathematical programming models (that is, one nonlinear program and two mixed-integer nonlinear programs) sequentially so as to satisfy different criteria in order of decreasing importance. Freshwater conservation is given the top priority in the present work because of its scarcity in environment and the pollution problems caused by wastewater effluents. Minimization of the total number of interconnections in the water network is treated as the next design goal since network complexity is directly related to operability, controllability and safety. The final step in the sequential procedure is to minimize the total throughput and, consequently, the operating and capital costs of all water using units as well. Five examples are presented in this paper to demonstrate the effectiveness of proposed procedure. When compared with the network designs obtained with available methods reported in literature, it can be observed that better solutions can usually be generated with our approach. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24128690 [article] Multiobjective optimization of water-using networks with multiple contaminants [texte imprimé] / Bao-Hong Li, Auteur . - 2011 . - pp. 5651-5660. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 9 (Mai 2011) . - pp. 5651-5660 Mots-clés : Pollution  Optimization Résumé : A systematic multiobjective optimization procedure is developed in this study to produce realistic multicontaminant water-using network designs. In every given design problem, the most appropriate structure is identitied by solving three mathematical programming models (that is, one nonlinear program and two mixed-integer nonlinear programs) sequentially so as to satisfy different criteria in order of decreasing importance. Freshwater conservation is given the top priority in the present work because of its scarcity in environment and the pollution problems caused by wastewater effluents. Minimization of the total number of interconnections in the water network is treated as the next design goal since network complexity is directly related to operability, controllability and safety. The final step in the sequential procedure is to minimize the total throughput and, consequently, the operating and capital costs of all water using units as well. Five examples are presented in this paper to demonstrate the effectiveness of proposed procedure. When compared with the network designs obtained with available methods reported in literature, it can be observed that better solutions can usually be generated with our approach. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24128690

Retrofitting heat exchanger networks based on simple pinch analysis / Bao-Hong Li in Industrial & engineering chemistry research, Vol. 49 N° 8 (Avril 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 8 (Avril 2010) . - pp. 3967–3971 Titre : Retrofitting heat exchanger networks based on simple pinch analysis Type de document : texte imprimé Auteurs : Bao-Hong Li, Auteur Année de publication : 2010 Article en page(s) : pp. 3967–3971 Note générale : Industrial Chemistry Langues : Anglais (eng) Mots-clés : Retrofitting  Heat  Exchanger  Networks  Based  Pinch  Analysis Résumé : It has been well-established that the energy and capital costs of a heat exchanger network are both dependent upon the minimum allowable temperature approach ΔTmin. As a result of the rapidly growing oil prices in recent years, there appears to be an urgent need to retrofit the existing “optimal” networks so as to reduce the current utility consumption rates with smaller ΔTmin values. A simple pinch-based approach is proposed here to accomplish this task while keeping additional capital investment to a reasonable level. In particular, every cross-pinch match is removed, and its heat loads on the hot and cold streams are both divided into two according to the pinch temperatures. At either side of the pinch, the divided heat loads on each stream are combined and then matched according to a systematic procedure derived from simple pinch analysis. Two examples are provided to illustrate this procedure. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9016607 [article] Retrofitting heat exchanger networks based on simple pinch analysis [texte imprimé] / Bao-Hong Li, Auteur . - 2010 . - pp. 3967–3971. Industrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 8 (Avril 2010) . - pp. 3967–3971 Mots-clés : Retrofitting  Heat  Exchanger  Networks  Based  Pinch  Analysis Résumé : It has been well-established that the energy and capital costs of a heat exchanger network are both dependent upon the minimum allowable temperature approach ΔTmin. As a result of the rapidly growing oil prices in recent years, there appears to be an urgent need to retrofit the existing “optimal” networks so as to reduce the current utility consumption rates with smaller ΔTmin values. A simple pinch-based approach is proposed here to accomplish this task while keeping additional capital investment to a reasonable level. In particular, every cross-pinch match is removed, and its heat loads on the hot and cold streams are both divided into two according to the pinch temperatures. At either side of the pinch, the divided heat loads on each stream are combined and then matched according to a systematic procedure derived from simple pinch analysis. Two examples are provided to illustrate this procedure. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9016607