Documents disponibles écrits par cet auteur

Efficient numerical solver for partially structured differential and algebraic equation systems / Flavio Manenti in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9979–9984 Titre : Efficient numerical solver for partially structured differential and algebraic equation systems Type de document : texte imprimé Auteurs : Flavio Manenti, Auteur ; Ivan Dones, Auteur ; Guido Buzzi-Ferraris, Auteur Année de publication : 2010 Article en page(s) : pp. 9979–9984 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Differential  and  algebraic  equations  Sparse  set Résumé : Given a sparse set of differential and algebraic equations (DAEs), it is always recommended to exploit the structure of the system’s sparsity (e.g., tridiagonal blocks matrix, band matrix, and staircase matrix, etc.), thus to use tailored numerical solvers in order to reduce the computation time. Very frequently, though, while highly structured, a couple of elements enter the description which make it difficult for the solvers to reach a solution. They are common in process control applications, where the states added to the plant description by the integral parts of the controllers introduce unstructured elements in the otherwise very structured Jacobian of the mathematical model. Such systems are characterized by a partially structured Jacobian, which inhibits the use of the solvers tailored to fit problems with fully structured matrices. In such cases, one can either use a solver with lower performance, resulting in larger computation times, or alternatively one seeks an approximation for the unstructured points. A solution to the handling of “dirty” Jacobians is presented, which is implemented in a DAE solver package available freely on the Internet. This novel DAE solver fully exploits the overall structure of the system’s sparsity, without compromising CPU computation time and precision of the results. A numerical comparison with different approaches is given by solving a DAE model representing an existing nonequilibrium distillation column. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9007908 [article] Efficient numerical solver for partially structured differential and algebraic equation systems [texte imprimé] / Flavio Manenti, Auteur ; Ivan Dones, Auteur ; Guido Buzzi-Ferraris, Auteur . - 2010 . - pp. 9979–9984. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9979–9984 Mots-clés : Differential  and  algebraic  equations  Sparse  set Résumé : Given a sparse set of differential and algebraic equations (DAEs), it is always recommended to exploit the structure of the system’s sparsity (e.g., tridiagonal blocks matrix, band matrix, and staircase matrix, etc.), thus to use tailored numerical solvers in order to reduce the computation time. Very frequently, though, while highly structured, a couple of elements enter the description which make it difficult for the solvers to reach a solution. They are common in process control applications, where the states added to the plant description by the integral parts of the controllers introduce unstructured elements in the otherwise very structured Jacobian of the mathematical model. Such systems are characterized by a partially structured Jacobian, which inhibits the use of the solvers tailored to fit problems with fully structured matrices. In such cases, one can either use a solver with lower performance, resulting in larger computation times, or alternatively one seeks an approximation for the unstructured points. A solution to the handling of “dirty” Jacobians is presented, which is implemented in a DAE solver package available freely on the Internet. This novel DAE solver fully exploits the overall structure of the system’s sparsity, without compromising CPU computation time and precision of the results. A numerical comparison with different approaches is given by solving a DAE model representing an existing nonequilibrium distillation column. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9007908

Fuzzy model-based predictive hybrid control of polymerization processes / Nádson M. Nascimento Lima in Industrial & engineering chemistry research, Vol. 48 N° 18 (Septembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 18 (Septembre 2009) . - pp. 8542–8550 Titre : Fuzzy model-based predictive hybrid control of polymerization processes Type de document : texte imprimé Auteurs : Nádson M. Nascimento Lima, Auteur ; Flavio Manenti, Auteur ; Rubens Maciel Filho, Auteur Année de publication : 2010 Article en page(s) : pp. 8542–8550 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Fuzzy  model-based  predictive  hybrid  controller  Polymerization  processes  Nonlinear  behaviors Résumé : This paper presents a fuzzy model-based predictive hybrid controller (FMPHC) for polymerization processes based on Takagi−Sugeno models and moving horizon methodology. Such processes are characterized by strongly nonlinear behaviors, which may either require significant effort to tune model-based controllers or render them ineffective. The proposed FMPHC is a promising integrated approach to handle nonlinearities and control issues. An industrial copolymerization process of ethylene and 1-butene is adopted to validate the proposed approach and to compare it to the most widespread advanced multivariable control. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900352d [article] Fuzzy model-based predictive hybrid control of polymerization processes [texte imprimé] / Nádson M. Nascimento Lima, Auteur ; Flavio Manenti, Auteur ; Rubens Maciel Filho, Auteur . - 2010 . - pp. 8542–8550. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 18 (Septembre 2009) . - pp. 8542–8550 Mots-clés : Fuzzy  model-based  predictive  hybrid  controller  Polymerization  processes  Nonlinear  behaviors Résumé : This paper presents a fuzzy model-based predictive hybrid controller (FMPHC) for polymerization processes based on Takagi−Sugeno models and moving horizon methodology. Such processes are characterized by strongly nonlinear behaviors, which may either require significant effort to tune model-based controllers or render them ineffective. The proposed FMPHC is a promising integrated approach to handle nonlinearities and control issues. An industrial copolymerization process of ethylene and 1-butene is adopted to validate the proposed approach and to compare it to the most widespread advanced multivariable control. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900352d

Nonlinear model predictive control / Ivan Dones in Industrial & engineering chemistry research, Vol. 49 N° 10 (Mai 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 10 (Mai 2010) . - pp. 4782–4791 Titre : Nonlinear model predictive control : a self - adaptive approach Type de document : texte imprimé Auteurs : Ivan Dones, Auteur ; Flavio Manenti, Auteur ; Heinz A. Preisig, Auteur Année de publication : 2010 Article en page(s) : pp. 4782–4791 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Dynamic  models  Predictive  Control Résumé : Model predictive control (MPC) is an online application based on dynamic models. Its application faces two major obstacles: (i) computational constraints and (ii) the need to accurately simulate the process by a model that properly predicts how the plant will behave in the future. Implementation of MPC is not always possible in large-scale or industrial applications due to the computational complexity of MPC and to the dimensionality of the models. To facilitate MPC implementations, this paper proposes a self-adaptive approach based on simplified (or reduced-order) nonlinear models. The proposed methodology yields an MPC that adjusts the dimension of the model according to both the current process conditions and the control objectives. The self-adaptive approach is described and validated on an industrial case study, a C4-splitter. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901693w [article] Nonlinear model predictive control : a self - adaptive approach [texte imprimé] / Ivan Dones, Auteur ; Flavio Manenti, Auteur ; Heinz A. Preisig, Auteur . - 2010 . - pp. 4782–4791. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 10 (Mai 2010) . - pp. 4782–4791 Mots-clés : Dynamic  models  Predictive  Control Résumé : Model predictive control (MPC) is an online application based on dynamic models. Its application faces two major obstacles: (i) computational constraints and (ii) the need to accurately simulate the process by a model that properly predicts how the plant will behave in the future. Implementation of MPC is not always possible in large-scale or industrial applications due to the computational complexity of MPC and to the dimensionality of the models. To facilitate MPC implementations, this paper proposes a self-adaptive approach based on simplified (or reduced-order) nonlinear models. The proposed methodology yields an MPC that adjusts the dimension of the model according to both the current process conditions and the control objectives. The self-adaptive approach is described and validated on an industrial case study, a C4-splitter. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901693w

Online data reconciliation with poor redundancy systems / Flavio Manenti in Industrial & engineering chemistry research, Vol. 50 N° 24 (Décembre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 24 (Décembre 2011) . - pp. 14105-14114 Titre : Online data reconciliation with poor redundancy systems Type de document : texte imprimé Auteurs : Flavio Manenti, Auteur ; Maria Grazia Grottoli, Auteur ; Sauro Pierucci, Auteur Année de publication : 2012 Article en page(s) : pp. 14105-14114 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Data  reconciliation Résumé : The paper deals with the integrated solution of different model-based optimization levels to face the problem of inferring and reconciling online plant measurements practically, under the condition of poor measure redundancy, because of a lack of instrumentation installed in the field. The novelty of the proposed computer-aided process engineering (CAPE) solution is in the simultaneous integration of different optimization levels: (i) the data reconciliation based on a detailed process simulation; (ii) the introduction and estimation of certain adaptive parameters, to match the current process conditions as well as to confer a certain generality on it; and (iii) the use of a set of efficient optimizers to improve plant operations. The online feasibility of the proposed CAPE solution is validated on a large-scale sulfur recovery unit (SRU) of an oil refinery. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25299879 [article] Online data reconciliation with poor redundancy systems [texte imprimé] / Flavio Manenti, Auteur ; Maria Grazia Grottoli, Auteur ; Sauro Pierucci, Auteur . - 2012 . - pp. 14105-14114. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 24 (Décembre 2011) . - pp. 14105-14114 Mots-clés : Data  reconciliation Résumé : The paper deals with the integrated solution of different model-based optimization levels to face the problem of inferring and reconciling online plant measurements practically, under the condition of poor measure redundancy, because of a lack of instrumentation installed in the field. The novelty of the proposed computer-aided process engineering (CAPE) solution is in the simultaneous integration of different optimization levels: (i) the data reconciliation based on a detailed process simulation; (ii) the introduction and estimation of certain adaptive parameters, to match the current process conditions as well as to confer a certain generality on it; and (iii) the use of a set of efficient optimizers to improve plant operations. The online feasibility of the proposed CAPE solution is validated on a large-scale sulfur recovery unit (SRU) of an oil refinery. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25299879

Sulfur recovery units / Stefano Signor 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. 5714–5724 Titre : Sulfur recovery units : adaptive simulation and model validation on an industrial plant Type de document : texte imprimé Auteurs : Stefano Signor, Auteur ; Flavio Manenti, Auteur ; Maria Grazia Grottoli, Auteur Année de publication : 2010 Article en page(s) : pp. 5714–5724 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Sulfur  recovery  units  Adaptive  simulation  parameters  Italy Résumé : The paper is aimed at discussing and fixing issues in providing a generalized approach to the simulation of sulfur recovery units (SRUs). The main goal is to get a simulation that is at the same time (i) reasonably detailed and robust to properly characterize SRUs and (ii) so generalized to provide a tool that is not only specific for the case in study. To achieve point (i), standard libraries belonging to commercial process simulators are coupled to specific heuristic relations coming from the industrial experience for modeling the thermal furnace and the catalytic Claus converters; this allows us to infer with a certain reliability those measures that are often missing or unavailable online in these processes. To achieve point (ii), a series of adaptive parameters are filled in the process simulation by making it more flexible and yet preserving all model details. The most recent techniques and numerical methods, to tune the adaptive simulation parameters, are implemented in Visual C++ and interfaced to PRO/II (by SimSci-Esscor) to obtain a robust parameter estimation solved by means of the BzzMath library. At last, the detailed and tuned adaptive simulation is validated along a period of 2 months on a large-scale SRU (TECHNIP-KTI SpA technology) operating in Italy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901749t [article] Sulfur recovery units : adaptive simulation and model validation on an industrial plant [texte imprimé] / Stefano Signor, Auteur ; Flavio Manenti, Auteur ; Maria Grazia Grottoli, Auteur . - 2010 . - pp. 5714–5724. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5714–5724 Mots-clés : Sulfur  recovery  units  Adaptive  simulation  parameters  Italy Résumé : The paper is aimed at discussing and fixing issues in providing a generalized approach to the simulation of sulfur recovery units (SRUs). The main goal is to get a simulation that is at the same time (i) reasonably detailed and robust to properly characterize SRUs and (ii) so generalized to provide a tool that is not only specific for the case in study. To achieve point (i), standard libraries belonging to commercial process simulators are coupled to specific heuristic relations coming from the industrial experience for modeling the thermal furnace and the catalytic Claus converters; this allows us to infer with a certain reliability those measures that are often missing or unavailable online in these processes. To achieve point (ii), a series of adaptive parameters are filled in the process simulation by making it more flexible and yet preserving all model details. The most recent techniques and numerical methods, to tune the adaptive simulation parameters, are implemented in Visual C++ and interfaced to PRO/II (by SimSci-Esscor) to obtain a robust parameter estimation solved by means of the BzzMath library. At last, the detailed and tuned adaptive simulation is validated along a period of 2 months on a large-scale SRU (TECHNIP-KTI SpA technology) operating in Italy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901749t