Documents disponibles écrits par cet auteur

Branch-and-cut algorithmic framework for 0-1 mixed-integer convex nonlinear programs / Hao Wu in Industrial & engineering chemistry research, Vol. 48 N° 20 (Octobre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9119–9127 Titre : Branch-and-cut algorithmic framework for 0-1 mixed-integer convex nonlinear programs Type de document : texte imprimé Auteurs : Hao Wu, Auteur ; Hao Wen, Auteur ; Yushan Zhu, Auteur Année de publication : 2010 Article en page(s) : pp. 9119–9127 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Branch-and-cut  algorithmic  framework  Mixed-Integer  Nonlinear  Optimizer  Nonlinear  programming Résumé : With widespread use of mixed-integer modeling for continuous and discontinuous nonlinear chemical processes, a robust mixed-integer nonlinear optimization algorithm is strongly demanded for the design and operation of chemical processes that achieve greater profits and also satisfy environmental and safety constraints. In this article, an extensive evaluation of a branch-and-cut algorithmic framework for 0−1 mixed-integer convex nonlinear programs, called MINO for Mixed-Integer Nonlinear Optimizer, is presented. The numerical performances of MINO are tested against four sets of medium-sized practical application problems from the fields of operations research and chemical engineering. The effects of the nonlinear programming (NLP) solvers, the cut generating and maintaining strategy, the node selection method, and the frequency of cut generation are examined, in order to handle MINLP problem with different mathematical structures. Preliminary computational results show that MINO exhibits a capability for handling practical MINLP problems that is comparable to that of the commercial solvers SBB and DICOPT, and it shows better performance for some problems for which either commercial solver encounters convergence problem within a CPU time limit of 6 h. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9001074 [article] Branch-and-cut algorithmic framework for 0-1 mixed-integer convex nonlinear programs [texte imprimé] / Hao Wu, Auteur ; Hao Wen, Auteur ; Yushan Zhu, Auteur . - 2010 . - pp. 9119–9127. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9119–9127 Mots-clés : Branch-and-cut  algorithmic  framework  Mixed-Integer  Nonlinear  Optimizer  Nonlinear  programming Résumé : With widespread use of mixed-integer modeling for continuous and discontinuous nonlinear chemical processes, a robust mixed-integer nonlinear optimization algorithm is strongly demanded for the design and operation of chemical processes that achieve greater profits and also satisfy environmental and safety constraints. In this article, an extensive evaluation of a branch-and-cut algorithmic framework for 0−1 mixed-integer convex nonlinear programs, called MINO for Mixed-Integer Nonlinear Optimizer, is presented. The numerical performances of MINO are tested against four sets of medium-sized practical application problems from the fields of operations research and chemical engineering. The effects of the nonlinear programming (NLP) solvers, the cut generating and maintaining strategy, the node selection method, and the frequency of cut generation are examined, in order to handle MINLP problem with different mathematical structures. Preliminary computational results show that MINO exhibits a capability for handling practical MINLP problems that is comparable to that of the commercial solvers SBB and DICOPT, and it shows better performance for some problems for which either commercial solver encounters convergence problem within a CPU time limit of 6 h. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9001074

Remixing control for divided - wall columns / Hao Ling in Industrial & engineering chemistry research, Vol. 50 N° 22 (Novembre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12694–12705 Titre : Remixing control for divided - wall columns Type de document : texte imprimé Auteurs : Hao Ling, Auteur ; Zhi Cai, Auteur ; Hao Wu, Auteur Année de publication : 2012 Article en page(s) : pp. 12694–12705 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Energy  saving Résumé : The divided-wall column is an energy-saving promising technology for the separation of ternary mixtures, but control is difficult because of its complexity structure and interactions of control loops. Although a few control methods have been reported, the general control method for all ternary mixtures is still pending because of the difference of relative volatilities. In this work, we explore a new control structure by control the remixing of the intermediate at the top trays in the prefractionator section for the separation of benzene, toluene, and o-xylene. It is found that avoiding the remixing of toluene helps the divided-wall column work very close to the optimal conditions. The remixing of toluene is studied at steady state first. Then, a remixing control structure with one remixing control loop and three composition control loops is presented. Minimized energy consumption is achieved by avoiding the remixing of toluene at the top of the prefractionator. Disturbances in feed flow rate and feed compositions are used to demonstrate the effectiveness of the proposed control structure. Remixing profile analysis of intermediate compounds gives an easy and new way to design and control the divided-wall column at energy saving conditions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201610g [article] Remixing control for divided - wall columns [texte imprimé] / Hao Ling, Auteur ; Zhi Cai, Auteur ; Hao Wu, Auteur . - 2012 . - pp. 12694–12705. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12694–12705 Mots-clés : Energy  saving Résumé : The divided-wall column is an energy-saving promising technology for the separation of ternary mixtures, but control is difficult because of its complexity structure and interactions of control loops. Although a few control methods have been reported, the general control method for all ternary mixtures is still pending because of the difference of relative volatilities. In this work, we explore a new control structure by control the remixing of the intermediate at the top trays in the prefractionator section for the separation of benzene, toluene, and o-xylene. It is found that avoiding the remixing of toluene helps the divided-wall column work very close to the optimal conditions. The remixing of toluene is studied at steady state first. Then, a remixing control structure with one remixing control loop and three composition control loops is presented. Minimized energy consumption is achieved by avoiding the remixing of toluene at the top of the prefractionator. Disturbances in feed flow rate and feed compositions are used to demonstrate the effectiveness of the proposed control structure. Remixing profile analysis of intermediate compounds gives an easy and new way to design and control the divided-wall column at energy saving conditions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201610g

Structure and dynamics of neat and CO2-reacted Ionic liquid tetrabutylphosphonium 2-cyanopyrrolide / Hao Wu in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8983–8993 Titre : Structure and dynamics of neat and CO2-reacted Ionic liquid tetrabutylphosphonium 2-cyanopyrrolide Type de document : texte imprimé Auteurs : Hao Wu, Auteur ; Jindal K. Shah, Auteur ; Craig M. Tenney, Auteur Année de publication : 2011 Article en page(s) : pp. 8983–8993 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ionic  liquid  Carbon  dioxide Résumé : Results of molecular dynamics simulations are reported in which the structure and dynamics of the reacted and unreacted forms of the task-specific ionic liquid (TSIL) tetrabutylphosphonium 2-cyanopyrrolide were computed. This particular ionic liquid is one of several newly discovered TSILs containing aprotic heterocyclic anions designed specifically for CO2 capture. The physical properties, liquid structure, and dynamics of the ionic liquid were computed as a function of extent of reaction with CO2. Translational and rotational dynamics showed little change upon reaction with CO2, in sharp contrast to traditional TSILs and consistent with experimental viscosity measurements. It is shown that this is due to the failure of a hydrogen-bond network to form upon reaction with CO2. The Henry’s law constants for the physical solubility of CO2, N2, O2, and H2O were computed for the unreacted TSIL and found to be comparable to values observed with other ionic liquids. In the reacted state, the solubility of CO2, N2, and O2 remained essentially unchanged, whereas the solubility of H2O increased by over a factor of 10 because of favorable hydrogen-bonding interactions with the carbamate. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395844 [article] Structure and dynamics of neat and CO2-reacted Ionic liquid tetrabutylphosphonium 2-cyanopyrrolide [texte imprimé] / Hao Wu, Auteur ; Jindal K. Shah, Auteur ; Craig M. Tenney, Auteur . - 2011 . - pp. 8983–8993. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8983–8993 Mots-clés : Ionic  liquid  Carbon  dioxide Résumé : Results of molecular dynamics simulations are reported in which the structure and dynamics of the reacted and unreacted forms of the task-specific ionic liquid (TSIL) tetrabutylphosphonium 2-cyanopyrrolide were computed. This particular ionic liquid is one of several newly discovered TSILs containing aprotic heterocyclic anions designed specifically for CO2 capture. The physical properties, liquid structure, and dynamics of the ionic liquid were computed as a function of extent of reaction with CO2. Translational and rotational dynamics showed little change upon reaction with CO2, in sharp contrast to traditional TSILs and consistent with experimental viscosity measurements. It is shown that this is due to the failure of a hydrogen-bond network to form upon reaction with CO2. The Henry’s law constants for the physical solubility of CO2, N2, O2, and H2O were computed for the unreacted TSIL and found to be comparable to values observed with other ionic liquids. In the reacted state, the solubility of CO2, N2, and O2 remained essentially unchanged, whereas the solubility of H2O increased by over a factor of 10 because of favorable hydrogen-bonding interactions with the carbamate. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395844