Documents disponibles écrits par cet auteur

Application of dynamic optimization techniques for poly(β-hydroxybutyrate) production in a fed-batch bioreactor / Lopez, Jimmy A. in Industrial & engineering chemistry research, Vol. 49 N° 4 (Fevrier 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 4 (Fevrier 2010) . - pp 1762–1769 Titre : Application of dynamic optimization techniques for poly(β-hydroxybutyrate) production in a fed-batch bioreactor Type de document : texte imprimé Auteurs : Lopez, Jimmy A., Auteur ; Verónica Bucalá, Auteur ; Villar, Marcelo A., Auteur Année de publication : 2010 Article en page(s) : pp 1762–1769 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Dynamic  optimization  Poly  β-hydroxybutyrate  Fed  batch  bioreactor. Résumé : Poly(β-hydroxybutyrate), PHB, is a microbial biopolymer produced by bacteria under unbalanced culture conditions. Such unbalanced conditions can be easily reached in a fed-batch bioreactor; therefore, it is important to know the system’s behavior as well as its constraints to induce unbalanced conditions that allow the optimization of feeding profiles and, consequently, PHB productivity. In this work, dynamic optimization has been applied to maximize PHB productivity in a fed-batch bioreactor. Optimal feeding profiles of carbon and nitrogen sources, as well as their respective concentrations, were obtained using gPROMS (generalized process modeling system). When there is reliable bioreaction kinetics available, dynamic optimization becomes a very valuable tool for predicting optimal operating conditions to maximize PHB productivity, with a considerable reduction in time and experimental costs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9006547 [article] Application of dynamic optimization techniques for poly(β-hydroxybutyrate) production in a fed-batch bioreactor [texte imprimé] / Lopez, Jimmy A., Auteur ; Verónica Bucalá, Auteur ; Villar, Marcelo A., Auteur . - 2010 . - pp 1762–1769. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 4 (Fevrier 2010) . - pp 1762–1769 Mots-clés : Dynamic  optimization  Poly  β-hydroxybutyrate  Fed  batch  bioreactor. Résumé : Poly(β-hydroxybutyrate), PHB, is a microbial biopolymer produced by bacteria under unbalanced culture conditions. Such unbalanced conditions can be easily reached in a fed-batch bioreactor; therefore, it is important to know the system’s behavior as well as its constraints to induce unbalanced conditions that allow the optimization of feeding profiles and, consequently, PHB productivity. In this work, dynamic optimization has been applied to maximize PHB productivity in a fed-batch bioreactor. Optimal feeding profiles of carbon and nitrogen sources, as well as their respective concentrations, were obtained using gPROMS (generalized process modeling system). When there is reliable bioreaction kinetics available, dynamic optimization becomes a very valuable tool for predicting optimal operating conditions to maximize PHB productivity, with a considerable reduction in time and experimental costs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9006547

Dynamics of an industrial fluidized-Bed granulator for urea production / Diego E. Bertín in Industrial & engineering chemistry research, Vol. 49 N° 1 (Janvier 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 1 (Janvier 2010) . - pp. 317–326 Titre : Dynamics of an industrial fluidized-Bed granulator for urea production Type de document : texte imprimé Auteurs : Diego E. Bertín, Auteur ; Juliana Pina, Auteur ; Verónica Bucalá, Auteur Année de publication : 2010 Article en page(s) : pp. 317–326 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Dynamics--Industrial--Fluidized-Bed--Granulator--Urea  Production Résumé : Granulation is one of the fundamental operations in particulate processing; however, there is still need to provide insight into the complex dynamic state behavior of these units. The unsteady state of an industrial multichamber fluidized-bed granulator for urea production, with variable mass holdup, is studied under different imposed step changes in key operating variables. For the assayed disturbances, the unit dynamics is considerably slow. In fact, many important state variables (e.g., bed height, pressure drop, solid mass flow, etc.) required more than 1 h to achieve the new steady state. The observed nonsteady behavior indicates the need of an efficient control to return the system rapidly to the desired operational point. The discharge area, fluidization air flow rate, and temperature were determined to be the more appropriate manipulative variables, for granulator stability control purposes. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901155a [article] Dynamics of an industrial fluidized-Bed granulator for urea production [texte imprimé] / Diego E. Bertín, Auteur ; Juliana Pina, Auteur ; Verónica Bucalá, Auteur . - 2010 . - pp. 317–326. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 1 (Janvier 2010) . - pp. 317–326 Mots-clés : Dynamics--Industrial--Fluidized-Bed--Granulator--Urea  Production Résumé : Granulation is one of the fundamental operations in particulate processing; however, there is still need to provide insight into the complex dynamic state behavior of these units. The unsteady state of an industrial multichamber fluidized-bed granulator for urea production, with variable mass holdup, is studied under different imposed step changes in key operating variables. For the assayed disturbances, the unit dynamics is considerably slow. In fact, many important state variables (e.g., bed height, pressure drop, solid mass flow, etc.) required more than 1 h to achieve the new steady state. The observed nonsteady behavior indicates the need of an efficient control to return the system rapidly to the desired operational point. The discharge area, fluidization air flow rate, and temperature were determined to be the more appropriate manipulative variables, for granulator stability control purposes. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901155a

Modeling of an industrial vibrating double-deck screen of a urea granulation circuit / Ivana M. Cotabarren in Industrial & engineering chemistry research, Vol. 48 N° 6 (Mars 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 6 (Mars 2009) . - pp. 3187–3196 Titre : Modeling of an industrial vibrating double-deck screen of a urea granulation circuit Type de document : texte imprimé Auteurs : Ivana M. Cotabarren, Auteur ; José Rossit, Auteur ; Verónica Bucalá, Auteur Année de publication : 2009 Article en page(s) : pp. 3187–3196 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Double-deck  screens  Urea  granulation  circuit  Screening  performance Résumé : A reliable mathematical model to predict the performance of double-deck screens from an industrial urea granulation circuit is provided in this work. The classification in each deck was described by the empirical model reported by Karra [Karra, V. K.Development of a Model for Predicting the Screening Performance of a Vibrating Screen. CIM Bull. 1979, 72, 804.] for the mining industry. The estimation of model parameters was based on industrial data collected from two large-scale double-deck screens belonging to a urea granulation plant. Prior to parameter fitting, data reconciliation of the solid streams was performed, with the aim of determining the unmeasured mass flows and the reconciled particle size distributions that fulfill the material balances for every size class. The results indicate that the fitted model reproduces in an accurate way the performance of the urea granules classification device. Thus, the screen mathematical representation can be used as a module of a plant simulator for many existing urea granulation circuits, which (independently of the technology) have similar industrial vibrating double-deck screens to attain the marketable product granulometry. In addition, the fitted model allows finding the optimal screen apertures to achieve the desired product attributes and recycle ratios. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800968y [article] Modeling of an industrial vibrating double-deck screen of a urea granulation circuit [texte imprimé] / Ivana M. Cotabarren, Auteur ; José Rossit, Auteur ; Verónica Bucalá, Auteur . - 2009 . - pp. 3187–3196. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 6 (Mars 2009) . - pp. 3187–3196 Mots-clés : Double-deck  screens  Urea  granulation  circuit  Screening  performance Résumé : A reliable mathematical model to predict the performance of double-deck screens from an industrial urea granulation circuit is provided in this work. The classification in each deck was described by the empirical model reported by Karra [Karra, V. K.Development of a Model for Predicting the Screening Performance of a Vibrating Screen. CIM Bull. 1979, 72, 804.] for the mining industry. The estimation of model parameters was based on industrial data collected from two large-scale double-deck screens belonging to a urea granulation plant. Prior to parameter fitting, data reconciliation of the solid streams was performed, with the aim of determining the unmeasured mass flows and the reconciled particle size distributions that fulfill the material balances for every size class. The results indicate that the fitted model reproduces in an accurate way the performance of the urea granules classification device. Thus, the screen mathematical representation can be used as a module of a plant simulator for many existing urea granulation circuits, which (independently of the technology) have similar industrial vibrating double-deck screens to attain the marketable product granulometry. In addition, the fitted model allows finding the optimal screen apertures to achieve the desired product attributes and recycle ratios. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800968y

Solids transport modeling in a fluidized drum granulator / Rodrigo Rojas in Industrial & engineering chemistry research, Vol. 49 N° 15 (Août 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 15 (Août 2010) . - pp 6986–6997 Titre : Solids transport modeling in a fluidized drum granulator Type de document : texte imprimé Auteurs : Rodrigo Rojas, Auteur ; Juliana Pina, Auteur ; Verónica Bucalá, Auteur Année de publication : 2010 Article en page(s) : pp 6986–6997 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Solids  transport  Granulator. Résumé : The fluidized-bed granulator (FDG) involves the use of a fluidized bed in a drum granulator, which is a horizontal cylinder fitted with internal flights. Despite its demonstrated success on an industrial scale, there are few published fundamental studies of this granulation process. In this work, a mathematical model to represent the solids flow pattern within the different active and passive zones of the rotating FDGs is developed. The fluidization table geometry as well as the angular velocity, drum inclination angle, and flights number strongly affect the mass holdups. Relatively high rotational speeds, inclination angles, and number of flights allow increasing the active mass holdups, reducing the passive mass, and eliminating the kilning flow. The model presented in this work, which accounts for the solids mass flows and holdups in the different zones of a FDG, provides a firm foundation for integration with energy and population balances. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901691v [article] Solids transport modeling in a fluidized drum granulator [texte imprimé] / Rodrigo Rojas, Auteur ; Juliana Pina, Auteur ; Verónica Bucalá, Auteur . - 2010 . - pp 6986–6997. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 15 (Août 2010) . - pp 6986–6997 Mots-clés : Solids  transport  Granulator. Résumé : The fluidized-bed granulator (FDG) involves the use of a fluidized bed in a drum granulator, which is a horizontal cylinder fitted with internal flights. Despite its demonstrated success on an industrial scale, there are few published fundamental studies of this granulation process. In this work, a mathematical model to represent the solids flow pattern within the different active and passive zones of the rotating FDGs is developed. The fluidization table geometry as well as the angular velocity, drum inclination angle, and flights number strongly affect the mass holdups. Relatively high rotational speeds, inclination angles, and number of flights allow increasing the active mass holdups, reducing the passive mass, and eliminating the kilning flow. The model presented in this work, which accounts for the solids mass flows and holdups in the different zones of a FDG, provides a firm foundation for integration with energy and population balances. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901691v