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Vol. 49 N° 17 - Septembre 1, 2010 [texte imprimé] . - 2010 . - p. 7701-8288 : ill. ; 28 cm. Chemical engineering Langues : Français (fre)
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Ajouter le résultat dans votre panierExtents of reaction, mass transfer and flow for gas−liquid reaction systems / Nirav Bhatt in Industrial & engineering chemistry research, Vol. 49 N° 17 (Septembre 1, 2010)
Titre : Extents of reaction, mass transfer and flow for gas−liquid reaction systems Type de document : texte imprimé Auteurs : Nirav Bhatt, Auteur ; Michael Amrhein, Auteur ; Dominique Bonvin, Auteur Année de publication : 2010 Article en page(s) : pp 7704–7717 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Mass transfer Gas liquid. Résumé : For gas−liquid reaction systems with inlet and outlet streams, this paper proposes a linear transformation of the numbers of moles into five distinct parts, namely, the extents of reaction, the extents of mass transfer, the extents of inlet flow, the extents of outlet flow, and invariants. Furthermore, we discuss several implications of being able to compute the various extents directly from the measured numbers of moles without knowledge of kinetic and mass-transfer rate expressions. The computation of extents is illustrated via the simulation of different reactor configurations for the chlorination of butanoic acid. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902015t
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7704–7717[article] Extents of reaction, mass transfer and flow for gas−liquid reaction systems [texte imprimé] / Nirav Bhatt, Auteur ; Michael Amrhein, Auteur ; Dominique Bonvin, Auteur . - 2010 . - pp 7704–7717.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7704–7717
Mots-clés : Mass transfer Gas liquid. Résumé : For gas−liquid reaction systems with inlet and outlet streams, this paper proposes a linear transformation of the numbers of moles into five distinct parts, namely, the extents of reaction, the extents of mass transfer, the extents of inlet flow, the extents of outlet flow, and invariants. Furthermore, we discuss several implications of being able to compute the various extents directly from the measured numbers of moles without knowledge of kinetic and mass-transfer rate expressions. The computation of extents is illustrated via the simulation of different reactor configurations for the chlorination of butanoic acid. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902015t Exemplaires
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Titre : Computational design of polymer nanocomposite coatings: a multiscale hierarchical approach for barrier property prediction Type de document : texte imprimé Auteurs : Jie Xiao, Auteur ; Yinlun Huang, Auteur ; Charles W. Manke, Auteur Année de publication : 2010 Article en page(s) : pp 7718–7727 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Polymer Nanocomposite Coatings. Résumé : In the development of polymer nanocomposites (PNCs), computational prediction of material properties is of great advantages in achieving rational and cost-effective design. This paper introduces a new multiscale hierarchical approach specifically tailored for PNCs property prediction. Due to its distinct features of generality and comprehensiveness, the introduced methodology outperforms most existing computational methods in this area. By this methodology, a wide range of PNCs containing any-shaped nanoparticles dispersed in a thermoplastic or thermoset polymer matrix can be thoroughly investigated for multiple property prediction. Furthermore, a reliable prediction is promoted by a systematic consideration of the intrinsic multiscale hierarchical structure of PNCs. Most importantly, an effective integration of different methods and theories at individual scales offers unique opportunities for gaining in-depth scientific understandings on the molecular structural origin of macroscopic property enhancement. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901927t
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7718–7727[article] Computational design of polymer nanocomposite coatings: a multiscale hierarchical approach for barrier property prediction [texte imprimé] / Jie Xiao, Auteur ; Yinlun Huang, Auteur ; Charles W. Manke, Auteur . - 2010 . - pp 7718–7727.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7718–7727
Mots-clés : Polymer Nanocomposite Coatings. Résumé : In the development of polymer nanocomposites (PNCs), computational prediction of material properties is of great advantages in achieving rational and cost-effective design. This paper introduces a new multiscale hierarchical approach specifically tailored for PNCs property prediction. Due to its distinct features of generality and comprehensiveness, the introduced methodology outperforms most existing computational methods in this area. By this methodology, a wide range of PNCs containing any-shaped nanoparticles dispersed in a thermoplastic or thermoset polymer matrix can be thoroughly investigated for multiple property prediction. Furthermore, a reliable prediction is promoted by a systematic consideration of the intrinsic multiscale hierarchical structure of PNCs. Most importantly, an effective integration of different methods and theories at individual scales offers unique opportunities for gaining in-depth scientific understandings on the molecular structural origin of macroscopic property enhancement. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901927t Exemplaires
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Titre : Controlled formation of nanostructures with desired geometries. 1. robust static structures Type de document : texte imprimé Auteurs : Earl O. P. Solis, Auteur ; Paul I. Barton, Auteur ; George Stephanopoulos, Auteur Année de publication : 2010 Article en page(s) : pp 7728–7745 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nanostructures Geometries Robust Static. Résumé : An essential requirement for the fabrication of future electronic, magnetic, optical, and biologically based devices, composed of constituents at the nanometer length scale, is the precise positioning of constituents in the system’s physical domain. The desired nanostructure must be locally stable to a desired level of robustness, which is the basis for the static design problem described in this paper: systematic use of externally imposed controls, realized through point conditions that introduce attractive or repulsive interaction terms in the system potential energy, to ensure a robust desired structure. The locations of the point conditions are found through the solution of a minimum tiling problem. Given these locations, the point condition strengths are found through the solution of combinatorially constrained optimization problems. System ergodicity must be broken to isolate the desired structure from all competing structures in phase space. We illustrate these static problem solution methods with 1- and 2-dimensional example lattice model systems. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100066v
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7728–7745[article] Controlled formation of nanostructures with desired geometries. 1. robust static structures [texte imprimé] / Earl O. P. Solis, Auteur ; Paul I. Barton, Auteur ; George Stephanopoulos, Auteur . - 2010 . - pp 7728–7745.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7728–7745
Mots-clés : Nanostructures Geometries Robust Static. Résumé : An essential requirement for the fabrication of future electronic, magnetic, optical, and biologically based devices, composed of constituents at the nanometer length scale, is the precise positioning of constituents in the system’s physical domain. The desired nanostructure must be locally stable to a desired level of robustness, which is the basis for the static design problem described in this paper: systematic use of externally imposed controls, realized through point conditions that introduce attractive or repulsive interaction terms in the system potential energy, to ensure a robust desired structure. The locations of the point conditions are found through the solution of a minimum tiling problem. Given these locations, the point condition strengths are found through the solution of combinatorially constrained optimization problems. System ergodicity must be broken to isolate the desired structure from all competing structures in phase space. We illustrate these static problem solution methods with 1- and 2-dimensional example lattice model systems. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100066v Exemplaires
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Titre : Controlled formation of nanostructures with desired geometries. 2. robust dynamic paths Type de document : texte imprimé Auteurs : Earl O. P. Solis, Auteur ; Paul I. Barton, Auteur ; George Stephanopoulos, Auteur Année de publication : 2010 Article en page(s) : pp 7746–7757 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nanostructures Geometries Robust Dynamic. Résumé : Part 2 of this series addresses the question of how to manipulate in time the positions and intensities of external controls so that a set of self-assembling nanoscale particles can always reach the nanostructure of desired geometry, starting from any random and unknown spatial distribution of the particles. It complements part 1 in which we examined how to position external controls and compute their intensities so that we can ensure that the final nanostructure with the desired geometry corresponds to a local potential energy minimum surrounded by sufficiently high energy barriers to ensure that the nanostructure is statistically robust, i.e., it remains at the desired geometry with an acceptably high probability. The proposed approach for the generation of robust dynamic self-assembly paths is based on a progressive reduction of the system phase space into subsets with progressively smaller numbers of locally allowable configurational states. In other words, it is based on a judicious progressive transition from ergodic to nonergodic subsystems. The subsets of allowable configurations in phase space are modeled by a wavelet-based spatial multiresolution view of the desired structure (in terms of the number of particles). This approach produces a prescription of the optimal control problem where the dynamic self-assembly of particles into the desired nanostructure is governed by the dynamic master equation of statistical mechanics. A genetic algorithm is used to solve the associated optimization problems at each time period and locate the position of the external controls in the physical domain, as well as their intensities over time. The approaches and methods are illustrated with 1- and 2-dimensional lattice example systems. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000778
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7746–7757[article] Controlled formation of nanostructures with desired geometries. 2. robust dynamic paths [texte imprimé] / Earl O. P. Solis, Auteur ; Paul I. Barton, Auteur ; George Stephanopoulos, Auteur . - 2010 . - pp 7746–7757.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7746–7757
Mots-clés : Nanostructures Geometries Robust Dynamic. Résumé : Part 2 of this series addresses the question of how to manipulate in time the positions and intensities of external controls so that a set of self-assembling nanoscale particles can always reach the nanostructure of desired geometry, starting from any random and unknown spatial distribution of the particles. It complements part 1 in which we examined how to position external controls and compute their intensities so that we can ensure that the final nanostructure with the desired geometry corresponds to a local potential energy minimum surrounded by sufficiently high energy barriers to ensure that the nanostructure is statistically robust, i.e., it remains at the desired geometry with an acceptably high probability. The proposed approach for the generation of robust dynamic self-assembly paths is based on a progressive reduction of the system phase space into subsets with progressively smaller numbers of locally allowable configurational states. In other words, it is based on a judicious progressive transition from ergodic to nonergodic subsystems. The subsets of allowable configurations in phase space are modeled by a wavelet-based spatial multiresolution view of the desired structure (in terms of the number of particles). This approach produces a prescription of the optimal control problem where the dynamic self-assembly of particles into the desired nanostructure is governed by the dynamic master equation of statistical mechanics. A genetic algorithm is used to solve the associated optimization problems at each time period and locate the position of the external controls in the physical domain, as well as their intensities over time. The approaches and methods are illustrated with 1- and 2-dimensional lattice example systems. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000778 Exemplaires
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Titre : OntoMODEL: ontological mathematical modeling knowledge management in pharmaceutical product development, 1: conceptual framework Type de document : texte imprimé Auteurs : Pradeep Suresh, Auteur ; Shuo-Huan Hsu, Auteur ; Pavan Akkisetty, Auteur Année de publication : 2010 Article en page(s) : pp 7758–7767 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Management pharmaceutical product. Résumé : Pharmaceutical product development is a critical step in the path of a drug therapy from its discovery to its delivery to the patient. It is capital-intensive, time-consuming, and extremely information- and knowledge-intensive. This presents various challenges to manage the information and knowledge involved in a systematic, reusable, and user-friendly manner. Knowledge, in this context, means decision-making knowledge and mathematical knowledge that capture the families of mathematical models that exist in this domain. In this paper, which is the first of this two-part series of papers, we describe OntoMODEL, which is an ontological tool for mechanistic mathematical model management that facilitates systematic and standardizable methods for model storage, usage, and solution. [Suresh and co-workers have presented discussions on OntoMODEL at AIChE meetings in San Francisco, CA (2006) and Salt Lake City, UT (2007), as well as at the 18th European Symposium on Computer-Aided Process Engineering (ESCAPE-18) in Lyon, France (2008).] While the declarative knowledge in mathematical models is captured using ontologies, the procedural knowledge required for solving these models is handled by commercially available scientific computing software such as Mathematica and an execution engine written in Java. The interactions involved are well-established and the approach-intuitive; therefore, they do not require user familiarity with any particular programming language or modeling software. Apart from this key benefit, the fact that OntoMODEL lends itself to more-advanced applications such as model-based fault diagnosis, model predictive control (which is decribed in the second paper of this series), knowledge-based decisionmaking, and process flowsheet simulation, making it a useful tool in the intelligent automation of process operations. This paper describes the framework and use of OntoMODEL and discusses how it overcomes the shortcomings of existing approaches toward managing mathematical modeling knowledge. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100246w
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7758–7767[article] OntoMODEL: ontological mathematical modeling knowledge management in pharmaceutical product development, 1: conceptual framework [texte imprimé] / Pradeep Suresh, Auteur ; Shuo-Huan Hsu, Auteur ; Pavan Akkisetty, Auteur . - 2010 . - pp 7758–7767.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7758–7767
Mots-clés : Management pharmaceutical product. Résumé : Pharmaceutical product development is a critical step in the path of a drug therapy from its discovery to its delivery to the patient. It is capital-intensive, time-consuming, and extremely information- and knowledge-intensive. This presents various challenges to manage the information and knowledge involved in a systematic, reusable, and user-friendly manner. Knowledge, in this context, means decision-making knowledge and mathematical knowledge that capture the families of mathematical models that exist in this domain. In this paper, which is the first of this two-part series of papers, we describe OntoMODEL, which is an ontological tool for mechanistic mathematical model management that facilitates systematic and standardizable methods for model storage, usage, and solution. [Suresh and co-workers have presented discussions on OntoMODEL at AIChE meetings in San Francisco, CA (2006) and Salt Lake City, UT (2007), as well as at the 18th European Symposium on Computer-Aided Process Engineering (ESCAPE-18) in Lyon, France (2008).] While the declarative knowledge in mathematical models is captured using ontologies, the procedural knowledge required for solving these models is handled by commercially available scientific computing software such as Mathematica and an execution engine written in Java. The interactions involved are well-established and the approach-intuitive; therefore, they do not require user familiarity with any particular programming language or modeling software. Apart from this key benefit, the fact that OntoMODEL lends itself to more-advanced applications such as model-based fault diagnosis, model predictive control (which is decribed in the second paper of this series), knowledge-based decisionmaking, and process flowsheet simulation, making it a useful tool in the intelligent automation of process operations. This paper describes the framework and use of OntoMODEL and discusses how it overcomes the shortcomings of existing approaches toward managing mathematical modeling knowledge. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100246w Exemplaires
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Titre : OntoMODEL: ontological mathematical modeling knowledge management in pharmaceutical product development, 2: applications Type de document : texte imprimé Auteurs : Pradeep Suresh, Auteur ; Shuo-Huan Hsu, Auteur ; Gintaras V. Reklaitis, Auteur Année de publication : 2010 Article en page(s) : pp 7768–7781 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Management pharmaceutical product Résumé : The challenges of managing the information and knowledge involved in pharmaceutical product development in a systematic and reusable, yet user-friendly, manner are very real and substantive. The benefits of managing the mathematical knowledge component in this can, by itself, lead to significant monetary and time savings, because of the reduced cost of interoperability. In the first part of this series, an ontological approach—namely, the OntoMODEL conceptual framework that addresses this need—has been presented. In this paper, applications of this framework are described, which involve the use of OntoMODEL as an integrated component of model-based decision support processes in the domain of model predictive control, in decision making associated with drug formulation and in drug process validation. OntoMODEL is shown to provide an easy and intuitive approach to analyze controller performance, which allows the user to experiment with various controller configurations with minimum effort. OntoMODEL can also effectively support the multilevel product formulation process involving both experimental results and evaluation of model-based performance indices. Finally, aspects of regulatory compliance that involve evaluation of models are also well-supported. This paper demonstrates that OntoMODEL can effectively serve as the multifunctional platform for mathematical model-based applications in the domain of chemical and pharmaceutical process and product development. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100258p
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7768–7781[article] OntoMODEL: ontological mathematical modeling knowledge management in pharmaceutical product development, 2: applications [texte imprimé] / Pradeep Suresh, Auteur ; Shuo-Huan Hsu, Auteur ; Gintaras V. Reklaitis, Auteur . - 2010 . - pp 7768–7781.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7768–7781
Mots-clés : Management pharmaceutical product Résumé : The challenges of managing the information and knowledge involved in pharmaceutical product development in a systematic and reusable, yet user-friendly, manner are very real and substantive. The benefits of managing the mathematical knowledge component in this can, by itself, lead to significant monetary and time savings, because of the reduced cost of interoperability. In the first part of this series, an ontological approach—namely, the OntoMODEL conceptual framework that addresses this need—has been presented. In this paper, applications of this framework are described, which involve the use of OntoMODEL as an integrated component of model-based decision support processes in the domain of model predictive control, in decision making associated with drug formulation and in drug process validation. OntoMODEL is shown to provide an easy and intuitive approach to analyze controller performance, which allows the user to experiment with various controller configurations with minimum effort. OntoMODEL can also effectively support the multilevel product formulation process involving both experimental results and evaluation of model-based performance indices. Finally, aspects of regulatory compliance that involve evaluation of models are also well-supported. This paper demonstrates that OntoMODEL can effectively serve as the multifunctional platform for mathematical model-based applications in the domain of chemical and pharmaceutical process and product development. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100258p Exemplaires
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Titre : Quantitative optimal experimental design using global sensitivity analysis via quasi-linearization Type de document : texte imprimé Auteurs : Yunfei Chu, Auteur ; Juergen Hahn, Auteur Année de publication : 2010 Article en page(s) : pp 7782–7794 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Quantitative optimal Analysis. Résumé : Local sensitivity analysis is widely used in experimental design to improve the precision of the estimated parameters. However, for nonlinear models, the local sensitivity values and the experimental design criteria are dependent on the, not yet known, parameter values. Global sensitivity analysis can deal with this situation by taking parameter uncertainty into account for computation of the sensitivity values. However, the existing experimental design criteria cannot easily be applied to the conventional global sensitivity analysis results. One outcome of this is that experimental design involving global sensitivity analysis has mainly focused on identification of influential parameters. A new global sensitivity analysis technique is presented in this work for the purpose of using this technique for quantitative experimental design. The methodology makes use of quasi-linearization and the global sensitivity matrix returned is the design matrix of the linearized model. Due to this, the same experimental criteria that have been developed for quantitative optimal design of linear models can be applied and serve as indicators of desired properties of the parameter estimates. The presented design using global sensitivity analysis is consistent with the popular design involving local sensitivity analysis when the parameter uncertainty is small; however, the technique outperforms local design when applied to models with significant parameter uncertainty. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9009827
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7782–7794[article] Quantitative optimal experimental design using global sensitivity analysis via quasi-linearization [texte imprimé] / Yunfei Chu, Auteur ; Juergen Hahn, Auteur . - 2010 . - pp 7782–7794.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7782–7794
Mots-clés : Quantitative optimal Analysis. Résumé : Local sensitivity analysis is widely used in experimental design to improve the precision of the estimated parameters. However, for nonlinear models, the local sensitivity values and the experimental design criteria are dependent on the, not yet known, parameter values. Global sensitivity analysis can deal with this situation by taking parameter uncertainty into account for computation of the sensitivity values. However, the existing experimental design criteria cannot easily be applied to the conventional global sensitivity analysis results. One outcome of this is that experimental design involving global sensitivity analysis has mainly focused on identification of influential parameters. A new global sensitivity analysis technique is presented in this work for the purpose of using this technique for quantitative experimental design. The methodology makes use of quasi-linearization and the global sensitivity matrix returned is the design matrix of the linearized model. Due to this, the same experimental criteria that have been developed for quantitative optimal design of linear models can be applied and serve as indicators of desired properties of the parameter estimates. The presented design using global sensitivity analysis is consistent with the popular design involving local sensitivity analysis when the parameter uncertainty is small; however, the technique outperforms local design when applied to models with significant parameter uncertainty. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9009827 Exemplaires
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Titre : Controller and estimator design for regulation of film thickness, surface roughness, and porosity in a multiscale thin film growth process Type de document : texte imprimé Auteurs : Xinyu Zhang, Auteur ; Gangshi Hu, Auteur ; Gerassimos Orkoulas, Auteur Année de publication : 2010 Article en page(s) : pp 7795–7806 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Estimator Growth process. Résumé : This work focuses on simultaneous regulation of film thickness, surface roughness, and porosity in a multiscale model of a thin film growth process using the inlet precursor concentration as the manipulated input. Specifically, under the assumption of continuum, a partial differential equation model is first derived to describe the dynamics of the precursor concentration in the gas phase. The thin film growth process is modeled via a microscopic kinetic Monte Carlo simulation model on a triangular lattice with vacancies and overhangs allowed to develop inside the film. Closed-form dynamic models of the thin film surface profile and porosity are developed and used as the basis for the design of model predictive control algorithms to simultaneously regulate film thickness, surface roughness, and porosity. Both state feedback and porosity estimation-based output feedback control algorithms are presented. Simulation results demonstrate the applicability and effectiveness of the proposed modeling and control approach by applying the proposed controllers to the multiscale model of the thin film growth process. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901396g
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7795–7806[article] Controller and estimator design for regulation of film thickness, surface roughness, and porosity in a multiscale thin film growth process [texte imprimé] / Xinyu Zhang, Auteur ; Gangshi Hu, Auteur ; Gerassimos Orkoulas, Auteur . - 2010 . - pp 7795–7806.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7795–7806
Mots-clés : Estimator Growth process. Résumé : This work focuses on simultaneous regulation of film thickness, surface roughness, and porosity in a multiscale model of a thin film growth process using the inlet precursor concentration as the manipulated input. Specifically, under the assumption of continuum, a partial differential equation model is first derived to describe the dynamics of the precursor concentration in the gas phase. The thin film growth process is modeled via a microscopic kinetic Monte Carlo simulation model on a triangular lattice with vacancies and overhangs allowed to develop inside the film. Closed-form dynamic models of the thin film surface profile and porosity are developed and used as the basis for the design of model predictive control algorithms to simultaneously regulate film thickness, surface roughness, and porosity. Both state feedback and porosity estimation-based output feedback control algorithms are presented. Simulation results demonstrate the applicability and effectiveness of the proposed modeling and control approach by applying the proposed controllers to the multiscale model of the thin film growth process. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901396g Exemplaires
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Titre : Area methods for relay feedback tests Type de document : texte imprimé Auteurs : Jietae Lee, Auteur ; Su Whan Sung, Auteur Année de publication : 2010 Article en page(s) : pp 7807–7813 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Area methods Feedback. Résumé : The amplitude and period of the relay feedback oscillation are used to obtain the ultimate parameter of a dynamic process and to tune a proportional−integral−derivative (PID) controller automatically. Equations for the ultimate gain and period are based on ignoring higher harmonic terms in the relay feedback response. The integral of the relay feedback response can suppress the higher harmonic terms, and the amplitude of this integral has been found to be better for estimating the ultimate gain of a process. As extensions, simpler methods that use several area calculations of the relay feedback response are proposed and shown to provide more accurate frequency responses, ultimate gain and period, and parametric models. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901546j
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7807–7813[article] Area methods for relay feedback tests [texte imprimé] / Jietae Lee, Auteur ; Su Whan Sung, Auteur . - 2010 . - pp 7807–7813.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7807–7813
Mots-clés : Area methods Feedback. Résumé : The amplitude and period of the relay feedback oscillation are used to obtain the ultimate parameter of a dynamic process and to tune a proportional−integral−derivative (PID) controller automatically. Equations for the ultimate gain and period are based on ignoring higher harmonic terms in the relay feedback response. The integral of the relay feedback response can suppress the higher harmonic terms, and the amplitude of this integral has been found to be better for estimating the ultimate gain of a process. As extensions, simpler methods that use several area calculations of the relay feedback response are proposed and shown to provide more accurate frequency responses, ultimate gain and period, and parametric models. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901546j Exemplaires
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Titre : Faster dynamic process simulation using In situ adaptive tabulation Type de document : texte imprimé Auteurs : Sidharth Abrol, Auteur ; Mingder Lu, Auteur ; David Hill, Auteur Année de publication : 2010 Article en page(s) : pp 7814–7823 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Dynamic process Tabulation. Résumé : In situ adaptive tabulation (ISAT) is applied to dynamic process simulators for reducing computational run-time. Several enhancements of previous approaches are presented here, including a method for estimating the sensitivities using input−output data, along with different strategies for record distribution. A modified version of the original algorithm (mISAT) to improve performance of ISAT is also suggested. Case studies for first-principles and data-driven models using ISAT are performed to generate accurate trajectories, which are essentially the same as those obtained by direct integration. Computational speed-up using ISAT is also shown for these studies. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901755f
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7814–7823[article] Faster dynamic process simulation using In situ adaptive tabulation [texte imprimé] / Sidharth Abrol, Auteur ; Mingder Lu, Auteur ; David Hill, Auteur . - 2010 . - pp 7814–7823.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7814–7823
Mots-clés : Dynamic process Tabulation. Résumé : In situ adaptive tabulation (ISAT) is applied to dynamic process simulators for reducing computational run-time. Several enhancements of previous approaches are presented here, including a method for estimating the sensitivities using input−output data, along with different strategies for record distribution. A modified version of the original algorithm (mISAT) to improve performance of ISAT is also suggested. Case studies for first-principles and data-driven models using ISAT are performed to generate accurate trajectories, which are essentially the same as those obtained by direct integration. Computational speed-up using ISAT is also shown for these studies. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901755f Exemplaires
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Titre : Constrained nonlinear estimation for industrial process fouling Type de document : texte imprimé Auteurs : Benjamin J. Spivey, Auteur ; John D. Hedengren, Auteur ; Thomas F. Edgar, Auteur Année de publication : 2010 Article en page(s) : pp 7824–7831 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nonlinear estimation Industrial process. Résumé : Industrial process monitoring tools require robust and efficient estimation techniques that maintain a high service factor by remaining online during abnormal operating conditions, such as during loss of measurements, changes in control status, or maintenance. Constraints incorporate additional process knowledge into estimation by bounding estimated disturbances within feasibility limits thereby providing robustness to faulty measurements or conditions that violate process models. Moving horizon estimation (MHE) and unscented Kalman filtering (UKF) are two estimation techniques that permit incorporation of constraints prior to evaluating the a priori estimate. This paper evaluates both constrained nonlinear estimators versus the extended Kalman filter (EKF) using industrial process data provided by ExxonMobil Chemical Company. Results provide short-term insight into the fouling process, and parameter estimates produced by UKF and MHE are shown to be more accurate than EKF. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9018116
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7824–7831[article] Constrained nonlinear estimation for industrial process fouling [texte imprimé] / Benjamin J. Spivey, Auteur ; John D. Hedengren, Auteur ; Thomas F. Edgar, Auteur . - 2010 . - pp 7824–7831.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7824–7831
Mots-clés : Nonlinear estimation Industrial process. Résumé : Industrial process monitoring tools require robust and efficient estimation techniques that maintain a high service factor by remaining online during abnormal operating conditions, such as during loss of measurements, changes in control status, or maintenance. Constraints incorporate additional process knowledge into estimation by bounding estimated disturbances within feasibility limits thereby providing robustness to faulty measurements or conditions that violate process models. Moving horizon estimation (MHE) and unscented Kalman filtering (UKF) are two estimation techniques that permit incorporation of constraints prior to evaluating the a priori estimate. This paper evaluates both constrained nonlinear estimators versus the extended Kalman filter (EKF) using industrial process data provided by ExxonMobil Chemical Company. Results provide short-term insight into the fouling process, and parameter estimates produced by UKF and MHE are shown to be more accurate than EKF. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9018116 Exemplaires
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Titre : Optimal selection of dominant measurements and manipulated variables for production control Type de document : texte imprimé Auteurs : Wuendy Abi Assali, Auteur ; Thomas McAvoy, Auteur Année de publication : 2010 Article en page(s) : pp 7832–7842 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Optimal Production control. Résumé : The main objective in operating a chemical plant is to improve profit while assuring products meet required specifications and plant operation satisfies environmental and operational constraints. A subobjective that directly affects profit is to improve the control performance of key economic variables in the plant, particularly the production rate and quality. An optimal control-based approach is proposed to determine a set of dominant measurements and manipulated variables and to structure them to improve control of the production rate and product quality. After the dominant variables are identified, a decentralized control structure is designed to control these variables. Then, a model predictive controller (MPC) is built on top of the decentralized control structure. The approach is applied to the Tennessee Eastman Process to demonstrate its effectiveness. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901879e
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7832–7842[article] Optimal selection of dominant measurements and manipulated variables for production control [texte imprimé] / Wuendy Abi Assali, Auteur ; Thomas McAvoy, Auteur . - 2010 . - pp 7832–7842.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7832–7842
Mots-clés : Optimal Production control. Résumé : The main objective in operating a chemical plant is to improve profit while assuring products meet required specifications and plant operation satisfies environmental and operational constraints. A subobjective that directly affects profit is to improve the control performance of key economic variables in the plant, particularly the production rate and quality. An optimal control-based approach is proposed to determine a set of dominant measurements and manipulated variables and to structure them to improve control of the production rate and product quality. After the dominant variables are identified, a decentralized control structure is designed to control these variables. Then, a model predictive controller (MPC) is built on top of the decentralized control structure. The approach is applied to the Tennessee Eastman Process to demonstrate its effectiveness. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901879e Exemplaires
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Titre : Automatic detection of stress states in type 1 diabetes subjects in ambulatory conditions Type de document : texte imprimé Auteurs : Daniel A. Finan, Auteur ; Howard Zisser, Auteur ; Lois Jovanovic, Auteur Année de publication : 2010 Article en page(s) : pp 7843–7848 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Automatic detection Ambulatory conditions. Résumé : Two levels of control are crucial to the robustness of an artificial β-cell, a medical device that would automatically regulate blood glucose levels in patients with type 1 diabetes. A low-level component would attempt to regulate blood glucose continuously, whereas a supervisory-level, or monitoring, component would detect underlying changes in the subject’s glucose−insulin dynamics and take corrective actions accordingly. These underlying changes, or “faults”, can include changes in insulin sensitivity, sensor problems, and insulin delivery problems, to name a few. A multivariate statistical monitoring technique, principal component analysis (PCA), has been applied to both simulated and experimental type 1 diabetes data. The objective of this study was to determine if PCA could be used to distinguish between normal patient data and data for abnormal conditions that included a variety of “faults.” The PCA results showed a high degree of accuracy; for data from nine type 1 diabetes subjects under ambulatory conditions, 33 of 37 total test days (89%), including fault days and normal days, were classified correctly. Therefore, the proposed monitoring technique shows considerable promise for incorporation into an artificial β-cell. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901891c
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7843–7848[article] Automatic detection of stress states in type 1 diabetes subjects in ambulatory conditions [texte imprimé] / Daniel A. Finan, Auteur ; Howard Zisser, Auteur ; Lois Jovanovic, Auteur . - 2010 . - pp 7843–7848.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7843–7848
Mots-clés : Automatic detection Ambulatory conditions. Résumé : Two levels of control are crucial to the robustness of an artificial β-cell, a medical device that would automatically regulate blood glucose levels in patients with type 1 diabetes. A low-level component would attempt to regulate blood glucose continuously, whereas a supervisory-level, or monitoring, component would detect underlying changes in the subject’s glucose−insulin dynamics and take corrective actions accordingly. These underlying changes, or “faults”, can include changes in insulin sensitivity, sensor problems, and insulin delivery problems, to name a few. A multivariate statistical monitoring technique, principal component analysis (PCA), has been applied to both simulated and experimental type 1 diabetes data. The objective of this study was to determine if PCA could be used to distinguish between normal patient data and data for abnormal conditions that included a variety of “faults.” The PCA results showed a high degree of accuracy; for data from nine type 1 diabetes subjects under ambulatory conditions, 33 of 37 total test days (89%), including fault days and normal days, were classified correctly. Therefore, the proposed monitoring technique shows considerable promise for incorporation into an artificial β-cell. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901891c Exemplaires
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Titre : Reconstruction-based contribution for process monitoring with kernel principal component analysis Type de document : texte imprimé Auteurs : Carlos F. Alcala, Auteur ; S. Joe Qin, Auteur Année de publication : 2010 Article en page(s) : pp 7849–7857 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Process monitoring Component analysis. Résumé : This paper presents a new method for fault diagnosis based on kernel principal component analysis (KPCA). The proposed method uses reconstruction-based contributions (RBC) to diagnose simple and complex faults in nonlinear principal component models based on KPCA. Similar to linear PCA, a combined index, based on the weighted combination of the Hotelling’s T2 and SPE indices, is proposed. Control limits for these fault detection indices are proposed using second-order moment approximation. The proposed fault detection and diagnosis scheme is tested with a simulated CSTR process where simple and complex faults are introduced. The simulation results show that the proposed fault detection and diagnosis methods are effective for KPCA. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9018947
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7849–7857[article] Reconstruction-based contribution for process monitoring with kernel principal component analysis [texte imprimé] / Carlos F. Alcala, Auteur ; S. Joe Qin, Auteur . - 2010 . - pp 7849–7857.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7849–7857
Mots-clés : Process monitoring Component analysis. Résumé : This paper presents a new method for fault diagnosis based on kernel principal component analysis (KPCA). The proposed method uses reconstruction-based contributions (RBC) to diagnose simple and complex faults in nonlinear principal component models based on KPCA. Similar to linear PCA, a combined index, based on the weighted combination of the Hotelling’s T2 and SPE indices, is proposed. Control limits for these fault detection indices are proposed using second-order moment approximation. The proposed fault detection and diagnosis scheme is tested with a simulated CSTR process where simple and complex faults are introduced. The simulation results show that the proposed fault detection and diagnosis methods are effective for KPCA. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9018947 Exemplaires
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Titre : Multivariate statistical process monitoring based on statistics pattern analysis Type de document : texte imprimé Auteurs : Jin Wang, Auteur ; Q. Peter He, Auteur Année de publication : 2010 Article en page(s) : pp 7858–7869 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Statistical process Pattern analysis. Résumé : In this work, a new multivariate method to monitor continuous processes is developed based on the statistics pattern analysis (SPA) framework. The SPA framework was proposed recently to address some challenges associated with batch process monitoring, such as unsynchronized batch trajectories and multimodal distribution. The major difference between the principal component analysis (PCA) based and SPA-based fault detection methods is that PCA monitors process variables while SPA monitors the statistics of process variables. In other words, PCA examines the variance−covariance of the process variables to perform fault detection while SPA examines the variance−covariance of the process variable statistics (e.g., mean, variance, autocorrelation, cross-correlation, etc.) to perform fault detection. In this paper, a window-based SPA method is proposed to address the challenges associated with continuous processes such as nonlinear process dynamics. First, the details of the window-based SPA method are presented; then the basic properties of the SPA method for fault detection are discussed and illustrated using a simple nonlinear example. Finally, the potential of the window-based SPA method in monitoring continuous processes is explored using two case studies (a 2 × 2 linear dynamic process and the challenging Tennessee Eastman process). The performance of the window-based SPA method is compared with the benchmark PCA and DPCA methods. The monitoring results clearly demonstrate the superiority of the proposed method. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901911p
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7858–7869[article] Multivariate statistical process monitoring based on statistics pattern analysis [texte imprimé] / Jin Wang, Auteur ; Q. Peter He, Auteur . - 2010 . - pp 7858–7869.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7858–7869
Mots-clés : Statistical process Pattern analysis. Résumé : In this work, a new multivariate method to monitor continuous processes is developed based on the statistics pattern analysis (SPA) framework. The SPA framework was proposed recently to address some challenges associated with batch process monitoring, such as unsynchronized batch trajectories and multimodal distribution. The major difference between the principal component analysis (PCA) based and SPA-based fault detection methods is that PCA monitors process variables while SPA monitors the statistics of process variables. In other words, PCA examines the variance−covariance of the process variables to perform fault detection while SPA examines the variance−covariance of the process variable statistics (e.g., mean, variance, autocorrelation, cross-correlation, etc.) to perform fault detection. In this paper, a window-based SPA method is proposed to address the challenges associated with continuous processes such as nonlinear process dynamics. First, the details of the window-based SPA method are presented; then the basic properties of the SPA method for fault detection are discussed and illustrated using a simple nonlinear example. Finally, the potential of the window-based SPA method in monitoring continuous processes is explored using two case studies (a 2 × 2 linear dynamic process and the challenging Tennessee Eastman process). The performance of the window-based SPA method is compared with the benchmark PCA and DPCA methods. The monitoring results clearly demonstrate the superiority of the proposed method. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901911p Exemplaires
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Titre : A modular approach to sustainability assessment and decision support in chemical process design Type de document : texte imprimé Auteurs : Mohamad R. Othman, Auteur ; Jens-Uwe Repke, Auteur ; Günter Wozny, Auteur Année de publication : 2010 Article en page(s) : pp 7870–7881 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Chemical process design. Résumé : In chemical and allied industries, process design sustainability has gained public concern in academia, industry, government agencies, and social groups. Over the past decade, a variety of sustainability indicators have been introduced, but with various challenges in application. It becomes clear that the industries need urgently practical tools for conducting systematic sustainability assessment on existing processes and/or new designs and, further, for helping derive the most desirable design decisions. This paper presents a systematic, general approach for sustainability assessment and design selection through integrating hard (quantitative) economic and environmental indicators along with soft (qualitative) indicators for social criteria into design activities. The approach contains four modules: a process simulator module, an equipment and inventory acquisition module, a sustainability assessment module, and a decision support module. The modules fully utilize and extend the capabilities of the process simulator Aspen Plus, Aspen Simulation Workbook, and a spreadsheet, where case model development, data acquisition and analysis, team contribution assessment, and decision support are effectively integrated. The efficacy of the introduced approach is illustrated by the example of biodiesel process design, where insightful sustainability analysis and persuasive decision support show its superiority over commonly practiced technoeconomy evaluation approaches. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901943d
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7870–7881[article] A modular approach to sustainability assessment and decision support in chemical process design [texte imprimé] / Mohamad R. Othman, Auteur ; Jens-Uwe Repke, Auteur ; Günter Wozny, Auteur . - 2010 . - pp 7870–7881.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7870–7881
Mots-clés : Chemical process design. Résumé : In chemical and allied industries, process design sustainability has gained public concern in academia, industry, government agencies, and social groups. Over the past decade, a variety of sustainability indicators have been introduced, but with various challenges in application. It becomes clear that the industries need urgently practical tools for conducting systematic sustainability assessment on existing processes and/or new designs and, further, for helping derive the most desirable design decisions. This paper presents a systematic, general approach for sustainability assessment and design selection through integrating hard (quantitative) economic and environmental indicators along with soft (qualitative) indicators for social criteria into design activities. The approach contains four modules: a process simulator module, an equipment and inventory acquisition module, a sustainability assessment module, and a decision support module. The modules fully utilize and extend the capabilities of the process simulator Aspen Plus, Aspen Simulation Workbook, and a spreadsheet, where case model development, data acquisition and analysis, team contribution assessment, and decision support are effectively integrated. The efficacy of the introduced approach is illustrated by the example of biodiesel process design, where insightful sustainability analysis and persuasive decision support show its superiority over commonly practiced technoeconomy evaluation approaches. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901943d Exemplaires
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Titre : Fast offset-free nonlinear model predictive control based on moving horizon estimation Type de document : texte imprimé Auteurs : Rui Huang, Auteur ; Lorenz T. Biegler, Auteur ; Sachin C. Patwardhan, Auteur Année de publication : 2010 Article en page(s) : pp 7882–7890 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Predictive control Nonlinear model. Résumé : To deal with plant−model mismatches in control practice, this paper proposes two variations of an offset-free framework which integrates nonlinear model predictive control (NMPC) and moving horizon estimation (MHE). We prove that the proposed method achieves offset-free regulatory behavior, even in the presence of plant−model mismatches. If the plant uncertainty structure is known, the MHE can be tuned to estimate uncertainty parameters, to remove the plant−model mismatch online. In addition, we incorporate the advanced step NMPC (as-NMPC) and the advanced step MHE (as-MHE) strategies into the proposed method to reduce online computational delay. Finally, the proposed method is applied on a large scale air separation unit, and the steady state offset-free behavior is observed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901945y
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7882–7890[article] Fast offset-free nonlinear model predictive control based on moving horizon estimation [texte imprimé] / Rui Huang, Auteur ; Lorenz T. Biegler, Auteur ; Sachin C. Patwardhan, Auteur . - 2010 . - pp 7882–7890.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7882–7890
Mots-clés : Predictive control Nonlinear model. Résumé : To deal with plant−model mismatches in control practice, this paper proposes two variations of an offset-free framework which integrates nonlinear model predictive control (NMPC) and moving horizon estimation (MHE). We prove that the proposed method achieves offset-free regulatory behavior, even in the presence of plant−model mismatches. If the plant uncertainty structure is known, the MHE can be tuned to estimate uncertainty parameters, to remove the plant−model mismatch online. In addition, we incorporate the advanced step NMPC (as-NMPC) and the advanced step MHE (as-MHE) strategies into the proposed method to reduce online computational delay. Finally, the proposed method is applied on a large scale air separation unit, and the steady state offset-free behavior is observed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901945y Exemplaires
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Titre : Optimal design and operation of a spatially distributed multiscale process, with regard to layered heterostructure growth Type de document : texte imprimé Auteurs : Christopher M. Behrens, Auteur ; Antonios Armaou, Auteur Année de publication : 2010 Article en page(s) : pp 7891–7900 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Optimal design Multiscale process Heterostructure. Résumé : Determining the optimal operation of processes modeled by multiscale systems presents many challenges, because of complexities in modeling and the extensive computational requirements needed to solve them. Application to layered heterostructure deposition is considered here, where an additional challenge of interface characterization is encountered. A solution methodology is applied to the fabrication of a device consisting of alternating layers of gallium arsenide and aluminum arsenide, with the intent of minimizing thickness nonuniformity and interfacial step density. Using a finite-element solver and kinetic Monte Carlo simulations, we were able to balance reductions in thickness nonuniformity and interfacial step density with maintaining favorable operating conditions in a computationally efficient manner. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9020107
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7891–7900[article] Optimal design and operation of a spatially distributed multiscale process, with regard to layered heterostructure growth [texte imprimé] / Christopher M. Behrens, Auteur ; Antonios Armaou, Auteur . - 2010 . - pp 7891–7900.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7891–7900
Mots-clés : Optimal design Multiscale process Heterostructure. Résumé : Determining the optimal operation of processes modeled by multiscale systems presents many challenges, because of complexities in modeling and the extensive computational requirements needed to solve them. Application to layered heterostructure deposition is considered here, where an additional challenge of interface characterization is encountered. A solution methodology is applied to the fabrication of a device consisting of alternating layers of gallium arsenide and aluminum arsenide, with the intent of minimizing thickness nonuniformity and interfacial step density. Using a finite-element solver and kinetic Monte Carlo simulations, we were able to balance reductions in thickness nonuniformity and interfacial step density with maintaining favorable operating conditions in a computationally efficient manner. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9020107 Exemplaires
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Titre : Fault detection and diagnosis using hidden markov disturbance models Type de document : texte imprimé Auteurs : Wee Chin Wong, Auteur ; Jay H. Lee, Auteur Année de publication : 2010 Article en page(s) : pp 7901–7908 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Detection Diagnosis Markov disturbance models. Résumé : Fault detection and diagnosis is critical for maintaining the health of process systems. Common fault signals include process and disturbance parameter changes, as well as sensor and actuator malfunctions typically manifested as persistent drifts or abrupt biases. These may be characterized by the existence of latent “fault” states. This work examines the effectiveness of a hidden Markov model framework for modeling such fault regimes. The proposed methodology may be interpreted as a generalization of the commonly employed mixture-of-Gaussians approach and is demonstrated through a shell-and-tube heat exchanger problem. Furthermore, the flexibility of the method is shown in the context of detecting valve stiction, a significant problem in the process industries. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9020655
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7901–7908[article] Fault detection and diagnosis using hidden markov disturbance models [texte imprimé] / Wee Chin Wong, Auteur ; Jay H. Lee, Auteur . - 2010 . - pp 7901–7908.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7901–7908
Mots-clés : Detection Diagnosis Markov disturbance models. Résumé : Fault detection and diagnosis is critical for maintaining the health of process systems. Common fault signals include process and disturbance parameter changes, as well as sensor and actuator malfunctions typically manifested as persistent drifts or abrupt biases. These may be characterized by the existence of latent “fault” states. This work examines the effectiveness of a hidden Markov model framework for modeling such fault regimes. The proposed methodology may be interpreted as a generalization of the commonly employed mixture-of-Gaussians approach and is demonstrated through a shell-and-tube heat exchanger problem. Furthermore, the flexibility of the method is shown in the context of detecting valve stiction, a significant problem in the process industries. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9020655 Exemplaires
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Titre : Simultaneous scheduling and control of multiproduct continuous parallel lines Type de document : texte imprimé Auteurs : Antonio Flores-Tlacuahuac, Auteur Année de publication : 2010 Article en page(s) : pp 7909–7921 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Simultaneous scheduling Parallel lines. Résumé : In this work, we propose a simultaneous scheduling and control optimization formulation to address both optimal steady-state production and dynamic product transitions in multiproduct parallel continuous stirred tank reactors (CSTRs). The simultaneous scheduling and control problem for multiproduct parallel continuous reactors is cast as a mixed-integer dynamic optimization (MIDO) problem. The reactor dynamic behavior is described by a set of nonlinear ordinary differential equations (ODEs) that are combined with the set of mixed-integer algebraic equations representing the optimal scheduling production model. The proposed simultaneous scheduling and control approach avoids suboptimal solutions that are obtained when both problems are solved in a decoupled way. Hence, the proposed optimization strategy can yield improved optimal solutions. The simultaneous approach for addressing the solution of dynamic optimization problems, based on orthogonal collocation on finite elements, is used to transform the set of ODEs into a mixed-integer nonlinear programming (MINLP) problem. Three multiproduct CSTRs are used to test the simultaneous scheduling and control optimization formulation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100024p
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7909–7921[article] Simultaneous scheduling and control of multiproduct continuous parallel lines [texte imprimé] / Antonio Flores-Tlacuahuac, Auteur . - 2010 . - pp 7909–7921.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7909–7921
Mots-clés : Simultaneous scheduling Parallel lines. Résumé : In this work, we propose a simultaneous scheduling and control optimization formulation to address both optimal steady-state production and dynamic product transitions in multiproduct parallel continuous stirred tank reactors (CSTRs). The simultaneous scheduling and control problem for multiproduct parallel continuous reactors is cast as a mixed-integer dynamic optimization (MIDO) problem. The reactor dynamic behavior is described by a set of nonlinear ordinary differential equations (ODEs) that are combined with the set of mixed-integer algebraic equations representing the optimal scheduling production model. The proposed simultaneous scheduling and control approach avoids suboptimal solutions that are obtained when both problems are solved in a decoupled way. Hence, the proposed optimization strategy can yield improved optimal solutions. The simultaneous approach for addressing the solution of dynamic optimization problems, based on orthogonal collocation on finite elements, is used to transform the set of ODEs into a mixed-integer nonlinear programming (MINLP) problem. Three multiproduct CSTRs are used to test the simultaneous scheduling and control optimization formulation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100024p Exemplaires
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Titre : Mathematical modeling, steady-state and dynamic behavior, and control of fuel cells: a review Type de document : texte imprimé Auteurs : Mona Bavarian, Auteur ; Masoud Soroush, Auteur Année de publication : 2010 Article en page(s) : pp 7922–7950 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Mathematical modeling Control fuel cells. Résumé : This paper presents a review of recent publications on mathematical modeling, steady-state and dynamic behavior, and control of polyelectrolyte membrane and solid oxide fuel cells. We limited the scope of this review to these two fuel cell types, which have been studied more, and have been reported to be more promising, than other fuel cell types. Zero-, one-, two-, and three-dimensional models developed to describe the behavior of the fuel cells are reviewed. Essential components of these models are highlighted. Conditions under which a fuel cell exhibits steady state multiplicity are described. Stability of the steady states is discussed. Processes that take place inside the fuel cells and contribute to the existence of multiple time-scales in the fuel cells are examined. Control configurations and strategies proposed and used for the fuel cells are reviewed, and advantages and disadvantages of each are listed. At the end, in view of the current status of the research activities, topics that require further research studies are discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100032c
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7922–7950[article] Mathematical modeling, steady-state and dynamic behavior, and control of fuel cells: a review [texte imprimé] / Mona Bavarian, Auteur ; Masoud Soroush, Auteur . - 2010 . - pp 7922–7950.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7922–7950
Mots-clés : Mathematical modeling Control fuel cells. Résumé : This paper presents a review of recent publications on mathematical modeling, steady-state and dynamic behavior, and control of polyelectrolyte membrane and solid oxide fuel cells. We limited the scope of this review to these two fuel cell types, which have been studied more, and have been reported to be more promising, than other fuel cell types. Zero-, one-, two-, and three-dimensional models developed to describe the behavior of the fuel cells are reviewed. Essential components of these models are highlighted. Conditions under which a fuel cell exhibits steady state multiplicity are described. Stability of the steady states is discussed. Processes that take place inside the fuel cells and contribute to the existence of multiple time-scales in the fuel cells are examined. Control configurations and strategies proposed and used for the fuel cells are reviewed, and advantages and disadvantages of each are listed. At the end, in view of the current status of the research activities, topics that require further research studies are discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100032c Exemplaires
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Titre : On the effects of tunable parameters of model predictive control on the locations of closed-loop eigenvalues Type de document : texte imprimé Auteurs : Jorge L. Garriga, Auteur ; Masoud Soroush, Auteur Année de publication : 2010 Article en page(s) : pp 7951–7956 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Tunable parameters Predictive control. Résumé : This paper presents an analytical study of the effects of model predictive control (MPC) tunable parameters on the closed-loop performance quantified in terms of the location(s) of closed-loop eigenvalue(s) of several common, single-input single-output, linear plants with inactive constraints. Symbolic manipulation capabilities of MATHEMATICA are used to obtain analytical expressions describing the dependence of closed-loop eigenvalues on the tunable parameters. This work is first to investigate how MPC tuning parameters affect the locations of the eigenvalues of the closed-loop system of a plant in the discrete-time setting. It provides theoretical basis/justification for several existing qualitative MPC tuning rules and proposes new tuning guidelines. For example, as the prediction horizon is increased while other tunable parameters remain constant, a subset of the closed-loop eigenvalues (poles) move toward the open-loop eigenvalues (poles) of the plant, if the plant is asymptotically stable. If a prediction horizon much longer than the reference-trajectory time constant is used, the value of the reference-trajectory time constant has little effect on the closed-loop performance. As the weights on the magnitude or the rate of change of the manipulated input are increased, the closed-loop eigenvalues move toward the open-loop eigenvalues. As the control horizon is increased from one, the dominant eigenvalue of the closed-loop system initially moves toward the origin and then away from the origin to a location that does not change with a further increase in the control horizon. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100030e
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7951–7956[article] On the effects of tunable parameters of model predictive control on the locations of closed-loop eigenvalues [texte imprimé] / Jorge L. Garriga, Auteur ; Masoud Soroush, Auteur . - 2010 . - pp 7951–7956.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7951–7956
Mots-clés : Tunable parameters Predictive control. Résumé : This paper presents an analytical study of the effects of model predictive control (MPC) tunable parameters on the closed-loop performance quantified in terms of the location(s) of closed-loop eigenvalue(s) of several common, single-input single-output, linear plants with inactive constraints. Symbolic manipulation capabilities of MATHEMATICA are used to obtain analytical expressions describing the dependence of closed-loop eigenvalues on the tunable parameters. This work is first to investigate how MPC tuning parameters affect the locations of the eigenvalues of the closed-loop system of a plant in the discrete-time setting. It provides theoretical basis/justification for several existing qualitative MPC tuning rules and proposes new tuning guidelines. For example, as the prediction horizon is increased while other tunable parameters remain constant, a subset of the closed-loop eigenvalues (poles) move toward the open-loop eigenvalues (poles) of the plant, if the plant is asymptotically stable. If a prediction horizon much longer than the reference-trajectory time constant is used, the value of the reference-trajectory time constant has little effect on the closed-loop performance. As the weights on the magnitude or the rate of change of the manipulated input are increased, the closed-loop eigenvalues move toward the open-loop eigenvalues. As the control horizon is increased from one, the dominant eigenvalue of the closed-loop system initially moves toward the origin and then away from the origin to a location that does not change with a further increase in the control horizon. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100030e Exemplaires
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Titre : A quasi-decentralized approach for networked state estimation and control of process systems Type de document : texte imprimé Auteurs : Yulei Sun, Auteur ; Nael H. El-Farra, Auteur Année de publication : 2010 Article en page(s) : pp 7957–7971 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Control process systems. Résumé : A quasi-decentralized state estimation and control architecture for plants with limited state measurements and distributed, interconnected units that exchange information over a shared communication network is developed in this work. The objective is to stabilize the plant while minimizing unnecessary network resource utilization and communication costs. The networked control architecture is composed of a family of local control systems that transmit their data in a discrete (on/off) fashion over the network. Each control system includes a state observer that generates estimates of the local state variables from the measured outputs. The estimates are used to implement the local feedback control law and are also shared over the network with the control systems of the interconnected units to account for the interactions between the units. To reduce the exchange of information over the network as much as possible without sacrificing stability, dynamic models of the interconnected units are embedded in the local control system of each unit to provide it with an estimate of the evolution of its neighbors when data are not transmitted through the network. The state of each model is then updated using the state estimate generated by the observer of the corresponding unit and transmitted over the network when communication is re-established. An explicit characterization of the maximum allowable update period (i.e., minimum cross communication frequency between the distributed control systems) needed to enforce the desired stability and performance properties is obtained in terms of the plant−model mismatch, controller, and observer design parameters. The design and implementation of the developed architecture are illustrated using a chemical plant example and compared with other possible networked control strategies. The comparison reveals that the lack of full state measurements imposes limitations on the maximum allowable update period, even if the models used to recreate the plant units’ dynamics are accurate. It is also shown that the quasi-decentralized control architecture is more robust than a centralized networked control structure, with respect to communication suspension. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000746
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7957–7971[article] A quasi-decentralized approach for networked state estimation and control of process systems [texte imprimé] / Yulei Sun, Auteur ; Nael H. El-Farra, Auteur . - 2010 . - pp 7957–7971.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7957–7971
Mots-clés : Control process systems. Résumé : A quasi-decentralized state estimation and control architecture for plants with limited state measurements and distributed, interconnected units that exchange information over a shared communication network is developed in this work. The objective is to stabilize the plant while minimizing unnecessary network resource utilization and communication costs. The networked control architecture is composed of a family of local control systems that transmit their data in a discrete (on/off) fashion over the network. Each control system includes a state observer that generates estimates of the local state variables from the measured outputs. The estimates are used to implement the local feedback control law and are also shared over the network with the control systems of the interconnected units to account for the interactions between the units. To reduce the exchange of information over the network as much as possible without sacrificing stability, dynamic models of the interconnected units are embedded in the local control system of each unit to provide it with an estimate of the evolution of its neighbors when data are not transmitted through the network. The state of each model is then updated using the state estimate generated by the observer of the corresponding unit and transmitted over the network when communication is re-established. An explicit characterization of the maximum allowable update period (i.e., minimum cross communication frequency between the distributed control systems) needed to enforce the desired stability and performance properties is obtained in terms of the plant−model mismatch, controller, and observer design parameters. The design and implementation of the developed architecture are illustrated using a chemical plant example and compared with other possible networked control strategies. The comparison reveals that the lack of full state measurements imposes limitations on the maximum allowable update period, even if the models used to recreate the plant units’ dynamics are accurate. It is also shown that the quasi-decentralized control architecture is more robust than a centralized networked control structure, with respect to communication suspension. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000746 Exemplaires
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Titre : Optimization of energy and water consumption in corn-based ethanol plants Type de document : texte imprimé Auteurs : Elvis Ahmetovic, Auteur ; Mariano Martin, Auteur ; Ignacio E. Grossmann, Auteur Année de publication : 2010 Article en page(s) : pp 7972–7982 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Optimization Energy Corn based ethanol. Résumé : In this paper we study the simultaneous energy and water consumption in the conceptual design of corn-based ethanol plants. A major goal is to reduce the freshwater consumption and wastewater discharge. We consider the corn-based ethanol plant reported in Karuppiah, et al. AICHE J. 2008, 54, 1499−1525. We review the major alternatives in the optimization of energy consumption and its impact in water consumption. Next, for each of the alternatives we synthesize an integrated process water network. This requires closing the loops for process and cooling water and steam, and implementing the proper treatment for the water streams. We show that minimizing energy consumption leads to process water networks with minimum water consumption. As a result, freshwater use is reduced to 1.54 galwater/galethanol, revealing that it is potentially possible to achieve levels of freshwater consumption that are significantly lower than the ones in current industrial operation and that wastewater discharged can also be reduced. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000955
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7972–7982[article] Optimization of energy and water consumption in corn-based ethanol plants [texte imprimé] / Elvis Ahmetovic, Auteur ; Mariano Martin, Auteur ; Ignacio E. Grossmann, Auteur . - 2010 . - pp 7972–7982.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7972–7982
Mots-clés : Optimization Energy Corn based ethanol. Résumé : In this paper we study the simultaneous energy and water consumption in the conceptual design of corn-based ethanol plants. A major goal is to reduce the freshwater consumption and wastewater discharge. We consider the corn-based ethanol plant reported in Karuppiah, et al. AICHE J. 2008, 54, 1499−1525. We review the major alternatives in the optimization of energy consumption and its impact in water consumption. Next, for each of the alternatives we synthesize an integrated process water network. This requires closing the loops for process and cooling water and steam, and implementing the proper treatment for the water streams. We show that minimizing energy consumption leads to process water networks with minimum water consumption. As a result, freshwater use is reduced to 1.54 galwater/galethanol, revealing that it is potentially possible to achieve levels of freshwater consumption that are significantly lower than the ones in current industrial operation and that wastewater discharged can also be reduced. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000955 Exemplaires
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Titre : Multiple model predictive control strategy for disturbance rejection Type de document : texte imprimé Auteurs : Matthew Kuure-Kinsey, Auteur ; B. Wayne Bequette, Auteur Année de publication : 2010 Article en page(s) : pp 7983–7989 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Predictive control Disturbance rejection. Résumé : Classical model-based control strategies assume a single disturbance model. In practice, the type of disturbance is often unknown or can change with time or multiple different disturbance types can occur simultaneously. In this paper, a multiple model predictive control strategy is developed to handle different disturbances, including multiple disturbances occurring simultaneously. A detailed discussion of disturbance model bank generation, state estimation, and disturbance model weighting is provided, and an unconstrained multiple model predictive control solution is formulated. Simulation results demonstrate successful estimation and control of single and multiple simultaneous disturbances. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100093c
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7983–7989[article] Multiple model predictive control strategy for disturbance rejection [texte imprimé] / Matthew Kuure-Kinsey, Auteur ; B. Wayne Bequette, Auteur . - 2010 . - pp 7983–7989.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7983–7989
Mots-clés : Predictive control Disturbance rejection. Résumé : Classical model-based control strategies assume a single disturbance model. In practice, the type of disturbance is often unknown or can change with time or multiple different disturbance types can occur simultaneously. In this paper, a multiple model predictive control strategy is developed to handle different disturbances, including multiple disturbances occurring simultaneously. A detailed discussion of disturbance model bank generation, state estimation, and disturbance model weighting is provided, and an unconstrained multiple model predictive control solution is formulated. Simulation results demonstrate successful estimation and control of single and multiple simultaneous disturbances. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100093c Exemplaires
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Titre : Maximum-likelihood parameter estimation for the thin-shell quasi-newtonian model for a laboratory blown film extruder Type de document : texte imprimé Auteurs : J. C. Pirkle, Auteur ; Jr., M. Fujiwara, Auteur ; R. D. Braatz, Auteur Année de publication : 2010 Article en page(s) : pp 8007–8015 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Maximum Likelihood Quasi Newtonian. Résumé : While most plastic films are manufactured by blown film extrusion, their first-principles modeling has remained substantially more challenging than for most other chemical engineering unit operations due to its combination of heat transfer, crystallization, and non-Newtonian fluid mechanics. This paper applies maximum-likelihood parameter estimation to characterize the convective heat transfer characteristics from measured spatial radii and temperature profiles for a laboratory-scale blown film process extruding a linear low density polyethylene (LLDPE) polymer. The Pearson and Petrie thin-film extrusion model incorporates (i) a quasi-Newtonian constitutive relation for the effect of temperature and crystallization on the viscosity of the polymer and (ii) a spatial variation of the heat transfer coefficient that is qualitatively consistent with turbulent flow simulations reported in the literature. A single heat transfer expression fit the experimental conditions for a cooling air flow rate of 1.5 m/s, whereas the variation of two parameters was able to fit all but one experimental condition for a cooling air flow rate of 1.0 m/s. The experimental condition that was poorly fit by the model had the highest takeup ratio, which was the operating condition closest to film instability and likely the condition most sensitive to the heat transfer relation. The experimental conditions corresponding to observed stable operations were investigated by linearized stability analysis. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100188g
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8007–8015[article] Maximum-likelihood parameter estimation for the thin-shell quasi-newtonian model for a laboratory blown film extruder [texte imprimé] / J. C. Pirkle, Auteur ; Jr., M. Fujiwara, Auteur ; R. D. Braatz, Auteur . - 2010 . - pp 8007–8015.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8007–8015
Mots-clés : Maximum Likelihood Quasi Newtonian. Résumé : While most plastic films are manufactured by blown film extrusion, their first-principles modeling has remained substantially more challenging than for most other chemical engineering unit operations due to its combination of heat transfer, crystallization, and non-Newtonian fluid mechanics. This paper applies maximum-likelihood parameter estimation to characterize the convective heat transfer characteristics from measured spatial radii and temperature profiles for a laboratory-scale blown film process extruding a linear low density polyethylene (LLDPE) polymer. The Pearson and Petrie thin-film extrusion model incorporates (i) a quasi-Newtonian constitutive relation for the effect of temperature and crystallization on the viscosity of the polymer and (ii) a spatial variation of the heat transfer coefficient that is qualitatively consistent with turbulent flow simulations reported in the literature. A single heat transfer expression fit the experimental conditions for a cooling air flow rate of 1.5 m/s, whereas the variation of two parameters was able to fit all but one experimental condition for a cooling air flow rate of 1.0 m/s. The experimental condition that was poorly fit by the model had the highest takeup ratio, which was the operating condition closest to film instability and likely the condition most sensitive to the heat transfer relation. The experimental conditions corresponding to observed stable operations were investigated by linearized stability analysis. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100188g Exemplaires
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Titre : Area method for a biased relay feedback system Type de document : texte imprimé Auteurs : Jietae Lee, Auteur ; Su Whan Sung, Auteur Année de publication : 2010 Article en page(s) : pp 8016–8020 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Biased relay Feedback system. Résumé : The relay feedback system often shows an asymmetric response because of initial transient states, disturbances, and process nonlinearity. To restore a symmetric response of the relay feedback system, an iterative adjustment of input or output bias is required. Instead of trying to obtain a symmetric response, the asymmetric response can be analyzed to estimate the ultimate data or a parametric model of process. However, the asymmetric response causes additional errors in estimating the ultimate properties of the process. An area method is proposed to reduce these errors. Because integrals (areas) of the relay responses reduce the effects of the high-order harmonic terms significantly, the proposed method shows better accuracy in obtaining frequency response data and parametric models compared with previous approaches. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1003027
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8016–8020[article] Area method for a biased relay feedback system [texte imprimé] / Jietae Lee, Auteur ; Su Whan Sung, Auteur . - 2010 . - pp 8016–8020.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8016–8020
Mots-clés : Biased relay Feedback system. Résumé : The relay feedback system often shows an asymmetric response because of initial transient states, disturbances, and process nonlinearity. To restore a symmetric response of the relay feedback system, an iterative adjustment of input or output bias is required. Instead of trying to obtain a symmetric response, the asymmetric response can be analyzed to estimate the ultimate data or a parametric model of process. However, the asymmetric response causes additional errors in estimating the ultimate properties of the process. An area method is proposed to reduce these errors. Because integrals (areas) of the relay responses reduce the effects of the high-order harmonic terms significantly, the proposed method shows better accuracy in obtaining frequency response data and parametric models compared with previous approaches. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1003027 Exemplaires
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Titre : Inference-based scheme for controlling product end-use properties in reactive extrusion processes Type de document : texte imprimé Auteurs : S. C. Garge, Auteur ; M. D. Wetzel, Auteur ; B. A. Ogunnaike, Auteur Année de publication : 2010 Article en page(s) : pp 8021–8034 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Reactive extrusion processes. Résumé : Reactive extrusion processes are typically multivariable, display highly nonlinear characteristics, and often have significant time delays associated with the (offline) measurements of key product properties. Achieving desired product characteristics in industrial practice has therefore been based primarily on the control of a single critical variable such as viscosity. However, increasingly stringent customer demand on product quality has rendered such strategies no longer viable and has necessitated the development of more comprehensive schemes that focus explicitly on controlling product quality characteristics. This paper reports on an experimentally validated inference-based control scheme for controlling product quality and end-use properties in reactive extrusion processes. The scheme employs inference models to predict infrequently measured properties at a much faster rate—predictions that are then used to take necessary control action in between samples, within a cascadelike structure involving separate and distinct multivariable controllers. The control scheme is evaluated first in simulation and then implemented experimentally via a Labview−Matlab interface on an actual pilot-scale reactive extrusion process, where product viscosity, tensile strength, and toughness are controlled simultaneously. Some representative results are presented to highlight the advantages and limitations of the scheme. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100435s
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8021–8034[article] Inference-based scheme for controlling product end-use properties in reactive extrusion processes [texte imprimé] / S. C. Garge, Auteur ; M. D. Wetzel, Auteur ; B. A. Ogunnaike, Auteur . - 2010 . - pp 8021–8034.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8021–8034
Mots-clés : Reactive extrusion processes. Résumé : Reactive extrusion processes are typically multivariable, display highly nonlinear characteristics, and often have significant time delays associated with the (offline) measurements of key product properties. Achieving desired product characteristics in industrial practice has therefore been based primarily on the control of a single critical variable such as viscosity. However, increasingly stringent customer demand on product quality has rendered such strategies no longer viable and has necessitated the development of more comprehensive schemes that focus explicitly on controlling product quality characteristics. This paper reports on an experimentally validated inference-based control scheme for controlling product quality and end-use properties in reactive extrusion processes. The scheme employs inference models to predict infrequently measured properties at a much faster rate—predictions that are then used to take necessary control action in between samples, within a cascadelike structure involving separate and distinct multivariable controllers. The control scheme is evaluated first in simulation and then implemented experimentally via a Labview−Matlab interface on an actual pilot-scale reactive extrusion process, where product viscosity, tensile strength, and toughness are controlled simultaneously. Some representative results are presented to highlight the advantages and limitations of the scheme. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100435s Exemplaires
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Titre : On the calculation of operability sets of nonlinear high-dimensional processes Type de document : texte imprimé Auteurs : Christos Georgakis, Auteur ; Lin Li, Auteur Année de publication : 2010 Article en page(s) : pp 8035–8047 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nonlinear high dimensional processes. Résumé : The calculation of the steady state operability characteristics of nonlinear high-dimensional processes is a difficult task computationally as it involves the mapping of high-dimensional, constrained input sets through the nonlinear process model to a high-dimensional output set. The reverse mapping, from outputs to inputs, also of interest, is equally challenging. In this paper we propose the selection of a finite number of points as an adequately accurate representation of the overall input-output mapping of the detailed model. This approach is motivated by the well established design of experiments (DoE) [Montgomery, D. C. Design and Analysis of Experiments; Wiley: New York, 2005. Box, G. E. P.; Draper, N. R. Response Surfaces, Mixtures, and Ridge Analysis; Wiley: Hoboken, NJ, 2007. Box, G. E. P.; Hunter, J. S.; Hunter, W. G. Statistics for Experimenters: Design, Innovation and Discovery, 2nd ed.; John Wiley & Sons, Inc.: Hoboken, NJ, 2004.] methodology which has been successful in experimentally investigating similar relationships for processes that have not yet been modeled. For this reason, the proposed approach is called design of selective calculations (DoSC). The mapping of only selective points and the development of an interpolative response surface model for the output points enables the calculation of the desired operability sets with a much reduced number of calculations without any significant loss of accuracy. The applicability of the developed method is illustrated with two motivating examples and a plant-wide industrial process, the Tennessee Eastman challenge problem. Of particular interest is the demonstration that the response surface model with quadratic terms is rich enough to accurately describe even the complex phenomenon of input multiplicity. When input multiplicity exists, the image of the boundary of the input set does not fully describe the boundary of the image set. In such a case, mapping only the boundaries of the related sets is not sufficient. Besides its overall computational economy, the proposed method overcomes this important additional challenge. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1009316
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8035–8047[article] On the calculation of operability sets of nonlinear high-dimensional processes [texte imprimé] / Christos Georgakis, Auteur ; Lin Li, Auteur . - 2010 . - pp 8035–8047.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8035–8047
Mots-clés : Nonlinear high dimensional processes. Résumé : The calculation of the steady state operability characteristics of nonlinear high-dimensional processes is a difficult task computationally as it involves the mapping of high-dimensional, constrained input sets through the nonlinear process model to a high-dimensional output set. The reverse mapping, from outputs to inputs, also of interest, is equally challenging. In this paper we propose the selection of a finite number of points as an adequately accurate representation of the overall input-output mapping of the detailed model. This approach is motivated by the well established design of experiments (DoE) [Montgomery, D. C. Design and Analysis of Experiments; Wiley: New York, 2005. Box, G. E. P.; Draper, N. R. Response Surfaces, Mixtures, and Ridge Analysis; Wiley: Hoboken, NJ, 2007. Box, G. E. P.; Hunter, J. S.; Hunter, W. G. Statistics for Experimenters: Design, Innovation and Discovery, 2nd ed.; John Wiley & Sons, Inc.: Hoboken, NJ, 2004.] methodology which has been successful in experimentally investigating similar relationships for processes that have not yet been modeled. For this reason, the proposed approach is called design of selective calculations (DoSC). The mapping of only selective points and the development of an interpolative response surface model for the output points enables the calculation of the desired operability sets with a much reduced number of calculations without any significant loss of accuracy. The applicability of the developed method is illustrated with two motivating examples and a plant-wide industrial process, the Tennessee Eastman challenge problem. Of particular interest is the demonstration that the response surface model with quadratic terms is rich enough to accurately describe even the complex phenomenon of input multiplicity. When input multiplicity exists, the image of the boundary of the input set does not fully describe the boundary of the image set. In such a case, mapping only the boundaries of the related sets is not sufficient. Besides its overall computational economy, the proposed method overcomes this important additional challenge. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1009316 Exemplaires
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Titre : Energy flow patterns and control implications for integrated distillation networks Type de document : texte imprimé Auteurs : Sujit S. Jogwar, Auteur ; Prodromos Daoutidis, Auteur Année de publication : 2010 Article en page(s) : pp 8048–8061 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Energy Integrated distillation networks. Résumé : This paper focuses on the dynamics and control of energy-integrated distillation networks. Typical examples of networks of distillation columns, with significant energy integration, are analyzed with the help of energy flow diagrams. Common patterns (e.g., recycle loops, throughput paths) are identified, which influence the dynamic characteristics of these networks. An example of double effect distillation is considered for detailed dynamic analysis and control. A simulation case study is presented to illustrate the application of the proposed framework. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101006v
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8048–8061[article] Energy flow patterns and control implications for integrated distillation networks [texte imprimé] / Sujit S. Jogwar, Auteur ; Prodromos Daoutidis, Auteur . - 2010 . - pp 8048–8061.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8048–8061
Mots-clés : Energy Integrated distillation networks. Résumé : This paper focuses on the dynamics and control of energy-integrated distillation networks. Typical examples of networks of distillation columns, with significant energy integration, are analyzed with the help of energy flow diagrams. Common patterns (e.g., recycle loops, throughput paths) are identified, which influence the dynamic characteristics of these networks. An example of double effect distillation is considered for detailed dynamic analysis and control. A simulation case study is presented to illustrate the application of the proposed framework. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101006v Exemplaires
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Titre : Incidents investigation and dynamic analysis of large alarm databases in chemical plants: a fluidized-catalytic-cracking unit case study Type de document : texte imprimé Auteurs : Ankur Pariyani, Auteur ; Warren D. Seider, Auteur Année de publication : 2010 Article en page(s) : pp 8062–8079 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Dynamic analysis Fluidized catalytic Cracking unit. Résumé : A novel framework to model the chronology of incidents is presented—depicting the relationship of initiating events with the various regulating and protection systems of the process—eventually leading to consequences, varying from zero to high severities. The key premise is that the departures and subsequent returns of process and product quality variables, from and to their normal operating ranges, are recognized as near-misses, which could have propagated to incidents. This leads to the availability of vast near-miss information recorded in distributed control and emergency shutdown systems databases that monitor the dynamics of the process. New performance indices, which utilize this abundant information, are introduced to conduct quantitative and qualitative (absolute and relative) assessment of the real-time safety and operability performances of an industrial fluidized-catalytic-cracking unit (FCCU) at a petroleum refinery. Also, new techniques for abnormal event tracking and recovery-time analysis are presented, which help to identify the variables that experience operational difficulties. It is shown how this information can be used to suggest improvements in the alarm-system structures for the FCCU. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9019648
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8062–8079[article] Incidents investigation and dynamic analysis of large alarm databases in chemical plants: a fluidized-catalytic-cracking unit case study [texte imprimé] / Ankur Pariyani, Auteur ; Warren D. Seider, Auteur . - 2010 . - pp 8062–8079.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8062–8079
Mots-clés : Dynamic analysis Fluidized catalytic Cracking unit. Résumé : A novel framework to model the chronology of incidents is presented—depicting the relationship of initiating events with the various regulating and protection systems of the process—eventually leading to consequences, varying from zero to high severities. The key premise is that the departures and subsequent returns of process and product quality variables, from and to their normal operating ranges, are recognized as near-misses, which could have propagated to incidents. This leads to the availability of vast near-miss information recorded in distributed control and emergency shutdown systems databases that monitor the dynamics of the process. New performance indices, which utilize this abundant information, are introduced to conduct quantitative and qualitative (absolute and relative) assessment of the real-time safety and operability performances of an industrial fluidized-catalytic-cracking unit (FCCU) at a petroleum refinery. Also, new techniques for abnormal event tracking and recovery-time analysis are presented, which help to identify the variables that experience operational difficulties. It is shown how this information can be used to suggest improvements in the alarm-system structures for the FCCU. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9019648 Exemplaires
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Titre : Large-scale parallel computation of incompressible flows by a domain decomposition-based least-squares finite element method Type de document : texte imprimé Auteurs : Xu Ding, Auteur ; Q. Y. Jiang, Auteur ; Tate T. H. Tsang, Auteur Année de publication : 2010 Article en page(s) : pp 8080–8085 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Incompressible flows Finite element method. Résumé : We have successfully developed a least-squares finite element method (LSFEM) for unsteady-state, three-dimensional convection dominated flows. The serial algorithm was used for simulations on a single CPU. In this work, our goal is to use a domain decomposition approach to parallelize the serial algorithm without much modifications of the serial code. We illustrate the efficiency of the parallel algorithm by flow simulations for more than 25 million unknowns. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100136b
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8080–8085[article] Large-scale parallel computation of incompressible flows by a domain decomposition-based least-squares finite element method [texte imprimé] / Xu Ding, Auteur ; Q. Y. Jiang, Auteur ; Tate T. H. Tsang, Auteur . - 2010 . - pp 8080–8085.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8080–8085
Mots-clés : Incompressible flows Finite element method. Résumé : We have successfully developed a least-squares finite element method (LSFEM) for unsteady-state, three-dimensional convection dominated flows. The serial algorithm was used for simulations on a single CPU. In this work, our goal is to use a domain decomposition approach to parallelize the serial algorithm without much modifications of the serial code. We illustrate the efficiency of the parallel algorithm by flow simulations for more than 25 million unknowns. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100136b Exemplaires
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Titre : Effects of partial dehydration and freezing temperature on the morphology and water binding capacity of carboxymethyl chitosan-based superabsorbents Type de document : texte imprimé Auteurs : Akram Zamani, Auteur ; Mohammad J. Taherzadeh, Auteur Année de publication : 2010 Article en page(s) : pp 8094–8099 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Morphology Dehydration Carboxymethyl. Résumé : Superabsorbent polymers (SAPs) were prepared from carboxymethyl chitosan (CMCS) cross-linked to a gel, concentrated by partial dehydration in a rotary evaporator (at 70, 85, and 100 °C), frozen at −5, −20, and −196 °C, and then freeze dried. A 0.9% aqueous solution of CMCS was gelled by addition of glutaraldehyde and partially dehydrated to 1.3−16.8% dry matter (DM) before freeze drying. The water binding capacity (WBC) of the products was up to 171 g/g of superabsorbent. The best results were obtained when 32−81% of the water in the gel was removed in the evaporator at 85−100 °C, and the concentrated gel (1.3−4.7% DM) was frozen in liquid nitrogen at −196 °C before freeze drying. On average, these SAPs, according to SEM micrographs, had a porous sponge-like structure and absorbed 35 and 32 g/g of saline and urine solutions after 10 min exposure, respectively. The corresponding WBC of two commercial polyacrylate-based SAPs was 34−57 g/g for saline and 30−37 g/g for urine solutions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100257s
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8094–8099[article] Effects of partial dehydration and freezing temperature on the morphology and water binding capacity of carboxymethyl chitosan-based superabsorbents [texte imprimé] / Akram Zamani, Auteur ; Mohammad J. Taherzadeh, Auteur . - 2010 . - pp 8094–8099.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8094–8099
Mots-clés : Morphology Dehydration Carboxymethyl. Résumé : Superabsorbent polymers (SAPs) were prepared from carboxymethyl chitosan (CMCS) cross-linked to a gel, concentrated by partial dehydration in a rotary evaporator (at 70, 85, and 100 °C), frozen at −5, −20, and −196 °C, and then freeze dried. A 0.9% aqueous solution of CMCS was gelled by addition of glutaraldehyde and partially dehydrated to 1.3−16.8% dry matter (DM) before freeze drying. The water binding capacity (WBC) of the products was up to 171 g/g of superabsorbent. The best results were obtained when 32−81% of the water in the gel was removed in the evaporator at 85−100 °C, and the concentrated gel (1.3−4.7% DM) was frozen in liquid nitrogen at −196 °C before freeze drying. On average, these SAPs, according to SEM micrographs, had a porous sponge-like structure and absorbed 35 and 32 g/g of saline and urine solutions after 10 min exposure, respectively. The corresponding WBC of two commercial polyacrylate-based SAPs was 34−57 g/g for saline and 30−37 g/g for urine solutions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100257s Exemplaires
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Titre : HBr−H2O2: a facile protocol for regioselective synthesis of bromohydrins and α-bromoketones and oxidation of benzylic/secondary alcohols to carbonyl compounds under mild aqueous conditions Type de document : texte imprimé Auteurs : Rajendra D. Patil, Auteur ; Girdhar Joshi, Auteur ; Subbarayappa Adimurthy, Auteur Année de publication : 2010 Article en page(s) : pp 8100–8105 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Bromohydrins Oxidation benzylic Mild aqueous. Résumé : HBr−H2O2 is efficiently activated in water under mild conditions, allowing the bromohydroxylation of various styrenes. HBr−H2O2 is more economic and easy to handle and offers sufficiently high regioselectivity (100%) for bromohydrin synthesis. Further activation of bromohydrin with a catalytic amount of HBr (50 mol %) and H2O2 in water affords α-bromoketones in moderate to good yields in a single step. Oxidation of benzylic/secondary alcohols to the corresponding carbonyl compounds has been achieved with the HBr (10 mol %) and H2O2 efficiently in aqueous dioxane under ambient conditions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100492r
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8100–8105[article] HBr−H2O2: a facile protocol for regioselective synthesis of bromohydrins and α-bromoketones and oxidation of benzylic/secondary alcohols to carbonyl compounds under mild aqueous conditions [texte imprimé] / Rajendra D. Patil, Auteur ; Girdhar Joshi, Auteur ; Subbarayappa Adimurthy, Auteur . - 2010 . - pp 8100–8105.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8100–8105
Mots-clés : Bromohydrins Oxidation benzylic Mild aqueous. Résumé : HBr−H2O2 is efficiently activated in water under mild conditions, allowing the bromohydroxylation of various styrenes. HBr−H2O2 is more economic and easy to handle and offers sufficiently high regioselectivity (100%) for bromohydrin synthesis. Further activation of bromohydrin with a catalytic amount of HBr (50 mol %) and H2O2 in water affords α-bromoketones in moderate to good yields in a single step. Oxidation of benzylic/secondary alcohols to the corresponding carbonyl compounds has been achieved with the HBr (10 mol %) and H2O2 efficiently in aqueous dioxane under ambient conditions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100492r Exemplaires
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Titre : Kinetics and equilibrium studies of adsorption of anionic dyes using acid-treated palm shell Type de document : texte imprimé Auteurs : G. Sreelatha, Auteur ; S. Kushwaha, Auteur ; V. J. Rao, Auteur Année de publication : 2010 Article en page(s) : pp 8106–8113 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetics Adsorption Anionic. Résumé : This study investigates the potential uses of palm shell, pretreated with sulfuric acid (APSP) for the adsorption of AOII, DSB, and AV7. The effects of different system variables like adsorbent dosage, pH, contact time, and temperature were studied. Optimum pH values for all the three dyes were determined as 1.0. Equilibrium was achieved within 30 min. Langmuir I, II, III, IV and Freundlich isotherm models were applied to describe the equilibrium isotherms at different temperatures, and the langmuir model was found to agree very well with the experimental data. The maximum adsorption capacity was found to be 2180.05 mg/g, 1199.99 mg/g, and 243.9 mg/g for AOII, DSB, and AV7, respectively. Thermodynamic parameters such as change in free energy (ΔG0), enthalpy (ΔH0), and entropy (ΔS0) were also determined. Pseudo-first-order, pseudo-second-order, and intraparticle diffusion models were used to fit the experimental data. The pseudo-second-order equation was able to fit well and provide a realistic description of the adsorption kinetics. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101004q
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8106–8113[article] Kinetics and equilibrium studies of adsorption of anionic dyes using acid-treated palm shell [texte imprimé] / G. Sreelatha, Auteur ; S. Kushwaha, Auteur ; V. J. Rao, Auteur . - 2010 . - pp 8106–8113.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8106–8113
Mots-clés : Kinetics Adsorption Anionic. Résumé : This study investigates the potential uses of palm shell, pretreated with sulfuric acid (APSP) for the adsorption of AOII, DSB, and AV7. The effects of different system variables like adsorbent dosage, pH, contact time, and temperature were studied. Optimum pH values for all the three dyes were determined as 1.0. Equilibrium was achieved within 30 min. Langmuir I, II, III, IV and Freundlich isotherm models were applied to describe the equilibrium isotherms at different temperatures, and the langmuir model was found to agree very well with the experimental data. The maximum adsorption capacity was found to be 2180.05 mg/g, 1199.99 mg/g, and 243.9 mg/g for AOII, DSB, and AV7, respectively. Thermodynamic parameters such as change in free energy (ΔG0), enthalpy (ΔH0), and entropy (ΔS0) were also determined. Pseudo-first-order, pseudo-second-order, and intraparticle diffusion models were used to fit the experimental data. The pseudo-second-order equation was able to fit well and provide a realistic description of the adsorption kinetics. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101004q Exemplaires
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Titre : Effectiveness factors for partially wetted catalysts Type de document : texte imprimé Auteurs : Arie Jan Van Houwelingen, Auteur ; Schalk Kok, Auteur ; Willie Nicol, Auteur Année de publication : 2010 Article en page(s) : pp 8114–8124 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalysts Partially wetted. Résumé : The finite element method (FEM) is used to solve the diffusion-reaction equation for spherical particles that are partially wetted by the liquid reagent in a trickle-bed reactor. Boundary conditions are specified using true wetting geometries from photographs of spherical particles that were partially wetted under trickle-flow conditions. Three types of reactions were investigated: completely liquid-limited reactions, completely gas-limited reactions, and reactions that are dependent on both the gas and the liquid reagent, following elementary kinetics. The study is limited to spheres, since wetting geometries were only available for these particles. Both monodispersed and eggshell catalysts were simulated. On the basis of the results, existing models for trickle-bed pellet efficiency factors were verified and models are proposed for the prediction of reaction rates in a partially wetted eggshell and monodispersed catalysts for gas-limited reactions, liquid-limited reactions, and elementary reactions for which both gas- and liquid-reagent concentrations are of importance. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9017176
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8114–8124[article] Effectiveness factors for partially wetted catalysts [texte imprimé] / Arie Jan Van Houwelingen, Auteur ; Schalk Kok, Auteur ; Willie Nicol, Auteur . - 2010 . - pp 8114–8124.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8114–8124
Mots-clés : Catalysts Partially wetted. Résumé : The finite element method (FEM) is used to solve the diffusion-reaction equation for spherical particles that are partially wetted by the liquid reagent in a trickle-bed reactor. Boundary conditions are specified using true wetting geometries from photographs of spherical particles that were partially wetted under trickle-flow conditions. Three types of reactions were investigated: completely liquid-limited reactions, completely gas-limited reactions, and reactions that are dependent on both the gas and the liquid reagent, following elementary kinetics. The study is limited to spheres, since wetting geometries were only available for these particles. Both monodispersed and eggshell catalysts were simulated. On the basis of the results, existing models for trickle-bed pellet efficiency factors were verified and models are proposed for the prediction of reaction rates in a partially wetted eggshell and monodispersed catalysts for gas-limited reactions, liquid-limited reactions, and elementary reactions for which both gas- and liquid-reagent concentrations are of importance. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9017176 Exemplaires
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Titre : Kinetics of heterogeneous catalytic epoxidation of propene with hydrogen peroxide over titanium silicalite (TS-1) Type de document : texte imprimé Auteurs : Sang Baek Shin, Auteur ; David Chadwick, Auteur Année de publication : 2010 Article en page(s) : pp 8125–8134 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetics Heterogeneous Catalytic. Résumé : The kinetics of the heterogeneous catalytic epoxidation of propene to propene oxide with hydrogen peroxide and titanium silicalite (TS-1) as the catalyst was studied under mild conditions in an autoclave reactor using methanol/water mixtures as the solvent. The effects of reactant concentration, solvent composition, catalyst loading, stirring speed, and reaction temperature on the propene oxidation were investigated. The initial rates increased almost linearly with catalyst loading. The apparent orders of reaction with respect to hydrogen peroxide and propene were found to be 0.67 (0.17−0.70 wt %) and 0.63 (0.3−0.8 bar), respectively. The apparent activation energy was found to be 25.8 kJ mol−1. Methanol content in the solvent was shown to have a dual influence on the reaction rate, enhancing the solubility of propene and inhibiting the epoxidation reaction by competitive adsorption. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100083u
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8125–8134[article] Kinetics of heterogeneous catalytic epoxidation of propene with hydrogen peroxide over titanium silicalite (TS-1) [texte imprimé] / Sang Baek Shin, Auteur ; David Chadwick, Auteur . - 2010 . - pp 8125–8134.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8125–8134
Mots-clés : Kinetics Heterogeneous Catalytic. Résumé : The kinetics of the heterogeneous catalytic epoxidation of propene to propene oxide with hydrogen peroxide and titanium silicalite (TS-1) as the catalyst was studied under mild conditions in an autoclave reactor using methanol/water mixtures as the solvent. The effects of reactant concentration, solvent composition, catalyst loading, stirring speed, and reaction temperature on the propene oxidation were investigated. The initial rates increased almost linearly with catalyst loading. The apparent orders of reaction with respect to hydrogen peroxide and propene were found to be 0.67 (0.17−0.70 wt %) and 0.63 (0.3−0.8 bar), respectively. The apparent activation energy was found to be 25.8 kJ mol−1. Methanol content in the solvent was shown to have a dual influence on the reaction rate, enhancing the solubility of propene and inhibiting the epoxidation reaction by competitive adsorption. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100083u Exemplaires
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Titre : Modeling of α-olefin copolymerization with chain-shuttling chemistry using dual catalysts in stirred-tank reactors: molecular weight distributions and copolymer composition Type de document : texte imprimé Auteurs : Min Zhang, Auteur Année de publication : 2010 Article en page(s) : pp 8135–8146 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalys Molecular weight Copolymer composition. Résumé : We report a kinetic model of chain-shuttling copolymerization using dual catalysts for solution α-olefin polymerization processes. This model focuses on predicting polymer properties such as the molecular weight and molecular weight distribution and the overall copolymer composition. We first validate the model through qualitative comparison between the model predictions and experimental observations reported in Arriola et al. ( Science2006, 312, 714) in both a semibatch reactor and a continuous stirred-tank reactor (CSTR). Then, examples are given to illustrate how the model can be used to examine the effects of the chain-shuttling rate constant and the chain-shuttling-agent feed rate in a CSTR. Moreover, simulations using this model demonstrate how to prepare polymers with desired properties by manipulating catalyst compositions and monomer compositions in the feed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100530p
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8135–8146[article] Modeling of α-olefin copolymerization with chain-shuttling chemistry using dual catalysts in stirred-tank reactors: molecular weight distributions and copolymer composition [texte imprimé] / Min Zhang, Auteur . - 2010 . - pp 8135–8146.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8135–8146
Mots-clés : Catalys Molecular weight Copolymer composition. Résumé : We report a kinetic model of chain-shuttling copolymerization using dual catalysts for solution α-olefin polymerization processes. This model focuses on predicting polymer properties such as the molecular weight and molecular weight distribution and the overall copolymer composition. We first validate the model through qualitative comparison between the model predictions and experimental observations reported in Arriola et al. ( Science2006, 312, 714) in both a semibatch reactor and a continuous stirred-tank reactor (CSTR). Then, examples are given to illustrate how the model can be used to examine the effects of the chain-shuttling rate constant and the chain-shuttling-agent feed rate in a CSTR. Moreover, simulations using this model demonstrate how to prepare polymers with desired properties by manipulating catalyst compositions and monomer compositions in the feed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100530p Exemplaires
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Titre : Microwave effect in the simultaneous removal of NOx and SO2 under electron beam irradiation and Kinetic investigation of NOx removal rate Type de document : texte imprimé Auteurs : Yong Kil Kwon, Auteur ; Do Hung Han, Auteur Année de publication : 2010 Article en page(s) : pp 8147–8156 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Microwave Electron Kinetic. Résumé : NOx and SO2 were removed from an air mixture in a flow process combining electron beam (EB) irradiation with microwave (MW) irradiation in order to improve the NOx removal efficiency. The addition of the MW irradiation considerably decreased the required EB doses compared to a single EB irradiation: for 80% removal efficiency the removal rate was increased by 21.1% to above 117.4% at initial NOx concentrations ranging from 250 to 1000 ppm. The increased NOx removal efficiency due to the MW irradiation addition was attributed to an intrinsic kinetic rather than a thermal effect. The removal process of SO2 and NOx with a stoichiometric ratio (M) addition of NH3 showed high removal efficiencies, as they were converted into main final products of NH4NO3 and (NH4)2SO4. The rate form of NOx removal (−rNOx = k[NOx][NH3][R•]) in the simultaneous removal of SO2 and NOx could be converted to a second-order rate according to the EB dose, instead of the irradiation time, and linear testing of this rate form with experimental data showed a good correlation, depending on the M value. The amount of NOx removed in the simultaneous removal of SO2 and NOx exhibited the following linear correlation: ΔC = k[NOx]o + ko with k = aDm + b and ko/Dn = aD + b. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100570q
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8147–8156[article] Microwave effect in the simultaneous removal of NOx and SO2 under electron beam irradiation and Kinetic investigation of NOx removal rate [texte imprimé] / Yong Kil Kwon, Auteur ; Do Hung Han, Auteur . - 2010 . - pp 8147–8156.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8147–8156
Mots-clés : Microwave Electron Kinetic. Résumé : NOx and SO2 were removed from an air mixture in a flow process combining electron beam (EB) irradiation with microwave (MW) irradiation in order to improve the NOx removal efficiency. The addition of the MW irradiation considerably decreased the required EB doses compared to a single EB irradiation: for 80% removal efficiency the removal rate was increased by 21.1% to above 117.4% at initial NOx concentrations ranging from 250 to 1000 ppm. The increased NOx removal efficiency due to the MW irradiation addition was attributed to an intrinsic kinetic rather than a thermal effect. The removal process of SO2 and NOx with a stoichiometric ratio (M) addition of NH3 showed high removal efficiencies, as they were converted into main final products of NH4NO3 and (NH4)2SO4. The rate form of NOx removal (−rNOx = k[NOx][NH3][R•]) in the simultaneous removal of SO2 and NOx could be converted to a second-order rate according to the EB dose, instead of the irradiation time, and linear testing of this rate form with experimental data showed a good correlation, depending on the M value. The amount of NOx removed in the simultaneous removal of SO2 and NOx exhibited the following linear correlation: ΔC = k[NOx]o + ko with k = aDm + b and ko/Dn = aD + b. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100570q Exemplaires
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Titre : SO3H-functionalized ionic liquid catalyzed alkylation of catechol with tert-butyl alcohol Type de document : texte imprimé Auteurs : Xiaowa Nie, Auteur ; Xin Liu, Auteur ; Lei Gao, Auteur Année de publication : 2010 Article en page(s) : pp 8157–8163 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ionic liquid Tert butyl alcohol. Résumé : Several SO3H-functionalized ionic liquids (FILs) were synthesized and their catalytic performances for catechol (CAT) alkylation with tert-butyl alcohol (TBA) were studied theoretically as well as experimentally. Under optimized reaction conditions, the conversion of CAT was 41.5%, and the selectivity for 4-tert-butyl catechol (4-TBC) could reach 97.1%. This electrophilic reaction exhibits a kinetics-dependent character. The higher frontier electron density at the C4 site, comparatively lower activation energy barrier (Ea), and higher thermodynamic stability all act in concert to make the reaction proceed preferentially toward 4-TBC. The FILs can lead to a much higher CAT conversion and a similar selectivity to 4-TBC compared to a Beta zeolite catalyst. Because the frontier electron density [fr(E)] of CAT was not significantly affected by the solvent, the product selectivity rule would not vary, whereas the addition of a solvent with a higher dielectric constant would slow the reaction by increasing Ea, thus resulting in a lower CAT conversion. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100800c
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8157–8163[article] SO3H-functionalized ionic liquid catalyzed alkylation of catechol with tert-butyl alcohol [texte imprimé] / Xiaowa Nie, Auteur ; Xin Liu, Auteur ; Lei Gao, Auteur . - 2010 . - pp 8157–8163.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8157–8163
Mots-clés : Ionic liquid Tert butyl alcohol. Résumé : Several SO3H-functionalized ionic liquids (FILs) were synthesized and their catalytic performances for catechol (CAT) alkylation with tert-butyl alcohol (TBA) were studied theoretically as well as experimentally. Under optimized reaction conditions, the conversion of CAT was 41.5%, and the selectivity for 4-tert-butyl catechol (4-TBC) could reach 97.1%. This electrophilic reaction exhibits a kinetics-dependent character. The higher frontier electron density at the C4 site, comparatively lower activation energy barrier (Ea), and higher thermodynamic stability all act in concert to make the reaction proceed preferentially toward 4-TBC. The FILs can lead to a much higher CAT conversion and a similar selectivity to 4-TBC compared to a Beta zeolite catalyst. Because the frontier electron density [fr(E)] of CAT was not significantly affected by the solvent, the product selectivity rule would not vary, whereas the addition of a solvent with a higher dielectric constant would slow the reaction by increasing Ea, thus resulting in a lower CAT conversion. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100800c Exemplaires
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Titre : Steam reforming of n-dodecane over ru−ni-based catalysts Type de document : texte imprimé Auteurs : Vidya Sagar Guggilla, Auteur ; Jale Akyurtlu, Auteur ; Ates Akyurtlu, Auteur Année de publication : 2010 Article en page(s) : pp 8164–8173 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Steam n Dodecane Catalysts. Résumé : Steam reforming of n-dodecane has been carried out with the goal of development of new and highly active catalysts for hydrogen production. Newly designed RuO-NiO-CeO2-Al2O3 catalysts have been successfully prepared with various loadings of Ni by sol−gel method. X-ray diffraction (XRD), H2 TPD, BET surface area, temperature-programmed reduction (TPR), and temperature-programmed desorption of CO2 (TPD of CO2) were used to characterize the prepared catalysts. The coke formation was studied by temperature programmed oxidation (TPO). The reforming of n-dodecane was carried out in a microreactor and investigated at different reaction temperatures, space velocity, steam/carbon ratio, and time-on-stream. Characterization results reveal that the presence of Ru and CeO2 enhances the catalyst reducibility. H2 TPD and CO2 TPD data indicate that 1 wt % Ru/2.5 wt % Ni/3 wt % CeO2/Al2O3 (1R2.5N3CA) catalyst exhibits larger nickel surface area and higher basicity compared to all the other catalysts. The activity and hydrogen yield of the 1R2.5N3CA catalyst are significantly higher than those of the other nickel catalysts under the same experimental conditions. Catalytic stability is also enhanced by the presence of ruthenium in nickel catalysts. Such improvement indicates that ruthenium plays an important role in the catalytic action of nickel. Overall, the bimetallic 1R2.5N3CA may be an effective catalyst for the production of hydrogen from n-dodecane. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100811g
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8164–8173[article] Steam reforming of n-dodecane over ru−ni-based catalysts [texte imprimé] / Vidya Sagar Guggilla, Auteur ; Jale Akyurtlu, Auteur ; Ates Akyurtlu, Auteur . - 2010 . - pp 8164–8173.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8164–8173
Mots-clés : Steam n Dodecane Catalysts. Résumé : Steam reforming of n-dodecane has been carried out with the goal of development of new and highly active catalysts for hydrogen production. Newly designed RuO-NiO-CeO2-Al2O3 catalysts have been successfully prepared with various loadings of Ni by sol−gel method. X-ray diffraction (XRD), H2 TPD, BET surface area, temperature-programmed reduction (TPR), and temperature-programmed desorption of CO2 (TPD of CO2) were used to characterize the prepared catalysts. The coke formation was studied by temperature programmed oxidation (TPO). The reforming of n-dodecane was carried out in a microreactor and investigated at different reaction temperatures, space velocity, steam/carbon ratio, and time-on-stream. Characterization results reveal that the presence of Ru and CeO2 enhances the catalyst reducibility. H2 TPD and CO2 TPD data indicate that 1 wt % Ru/2.5 wt % Ni/3 wt % CeO2/Al2O3 (1R2.5N3CA) catalyst exhibits larger nickel surface area and higher basicity compared to all the other catalysts. The activity and hydrogen yield of the 1R2.5N3CA catalyst are significantly higher than those of the other nickel catalysts under the same experimental conditions. Catalytic stability is also enhanced by the presence of ruthenium in nickel catalysts. Such improvement indicates that ruthenium plays an important role in the catalytic action of nickel. Overall, the bimetallic 1R2.5N3CA may be an effective catalyst for the production of hydrogen from n-dodecane. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100811g Exemplaires
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Titre : More benign synthesis of palladium nanoparticles in dimethyl sulfoxide and their extraction into an organic pohase Type de document : texte imprimé Auteurs : Juncheng Liu, Auteur ; Nicholas Ruffini, Auteur ; Pamela Pollet, Auteur Année de publication : 2010 Article en page(s) : pp 8174–8179 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nanoparticles Dimethyl Organic phase. Résumé : We present the successful synthesis and stabilization of 3.5 nm Pd nanoparticles (standard deviation of 0.49 nm) within dimethyl sulfoxide (DMSO) via fast, homogeneous reduction of a Pd salt using NaBH4 in the absence of traditional capping ligands. These Pd nanoparticles were found to be extremely stable and did not exhibit precipitation and/or agglomeration within the DMSO solvent even after more than 9 months. Moreover, these Pd nanoparticles were conveniently separated from the DMSO solvent medium via vacuum freeze drying by taking advantage of the high freezing point of DMSO. We have also successfully extracted the Pd nanoparticles from the DMSO phase into an organic phase (i.e., hexane), thereby providing a facile and efficient means for the generation of organic phase dispersible metal nanoparticles with complete recycle of the DMSO solvent. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902013g
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8174–8179[article] More benign synthesis of palladium nanoparticles in dimethyl sulfoxide and their extraction into an organic pohase [texte imprimé] / Juncheng Liu, Auteur ; Nicholas Ruffini, Auteur ; Pamela Pollet, Auteur . - 2010 . - pp 8174–8179.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8174–8179
Mots-clés : Nanoparticles Dimethyl Organic phase. Résumé : We present the successful synthesis and stabilization of 3.5 nm Pd nanoparticles (standard deviation of 0.49 nm) within dimethyl sulfoxide (DMSO) via fast, homogeneous reduction of a Pd salt using NaBH4 in the absence of traditional capping ligands. These Pd nanoparticles were found to be extremely stable and did not exhibit precipitation and/or agglomeration within the DMSO solvent even after more than 9 months. Moreover, these Pd nanoparticles were conveniently separated from the DMSO solvent medium via vacuum freeze drying by taking advantage of the high freezing point of DMSO. We have also successfully extracted the Pd nanoparticles from the DMSO phase into an organic phase (i.e., hexane), thereby providing a facile and efficient means for the generation of organic phase dispersible metal nanoparticles with complete recycle of the DMSO solvent. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902013g Exemplaires
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Titre : Size-controlled syntheses of nanoporous silica spherical particles through a microfluidic approach Type de document : texte imprimé Auteurs : Kota Shiba, Auteur ; Kumiko Kambara, Auteur ; Makoto Ogawa, Auteur Année de publication : 2010 Article en page(s) : pp 8180–8183 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nanoporous silica Microfluidic. Résumé : Monodispersed spherical particles of silica/surfactant hybrid with the particle size of 200−400 nm were successfully synthesized by a microfluidic reaction for nucleation and subsequent growth process under ambient condition and were transformed into nanoporous spherical particles with uniform pore size of ca. 2 nm and BET surface area of 500−1000 m2 g−1. Compared to the results obtained by conventional batch method using identical starting solution, the products obtained utilizing microfluidic syntheses showed narrower particle size distribution as a result of separating nucleation and growth processes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://fr.babelfish.yahoo.com/translate_txt
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8180–8183[article] Size-controlled syntheses of nanoporous silica spherical particles through a microfluidic approach [texte imprimé] / Kota Shiba, Auteur ; Kumiko Kambara, Auteur ; Makoto Ogawa, Auteur . - 2010 . - pp 8180–8183.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8180–8183
Mots-clés : Nanoporous silica Microfluidic. Résumé : Monodispersed spherical particles of silica/surfactant hybrid with the particle size of 200−400 nm were successfully synthesized by a microfluidic reaction for nucleation and subsequent growth process under ambient condition and were transformed into nanoporous spherical particles with uniform pore size of ca. 2 nm and BET surface area of 500−1000 m2 g−1. Compared to the results obtained by conventional batch method using identical starting solution, the products obtained utilizing microfluidic syntheses showed narrower particle size distribution as a result of separating nucleation and growth processes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://fr.babelfish.yahoo.com/translate_txt Exemplaires
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Titre : Effect of thermal treatment of silica gels on their amino functionalization and subsequent adsorption properties for Cu2+ from aqueous solution of copper sulfate Type de document : texte imprimé Auteurs : Manu V., Auteur ; Haresh M. Mody, Auteur ; Hari C. Bajaj, Auteur Année de publication : 2010 Article en page(s) : pp 8184–8191 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Thermal treatment Aqueous solution. Résumé : Hydrothermally prepared mesoporous silica gel (prepared under acidic condition) was calcined at different temperatures to control concentration of surface hydroxyl groups. These materials were functionalized with 3-aminopropyltrimethoxysilane (APTMS) and used for the adsorption of Cu2+ ions. Adsorption isotherm and adsorption capacity of the amine functionalized materials for Cu2+ were followed by inductively coupled plasma optical emission spectrometry (ICP-OES). The adsorption capacity for functionalized silica gel was correlated with population density of hydroxyl groups and hence amine content in the materials, which was determined by CHN analysis. Nitrogen adsorption/desorption measurements at liquid N2 temperature, Fourier transform infrared spectrometry (FTIR), and 29Si MAS NMR spectra were used to follow the changes in the textural parameters and surface properties of the mesoporous silica gel samples. This study indicates that thermal treatment of silica gel determines the population density of surface hydroxyl groups and hence the NH2 population density after functionalization of the gels, which in turn determines the NH2/Cu2+ ratio at saturation of Cu2+ on the functionalized silica gel. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1007773
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8184–8191[article] Effect of thermal treatment of silica gels on their amino functionalization and subsequent adsorption properties for Cu2+ from aqueous solution of copper sulfate [texte imprimé] / Manu V., Auteur ; Haresh M. Mody, Auteur ; Hari C. Bajaj, Auteur . - 2010 . - pp 8184–8191.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8184–8191
Mots-clés : Thermal treatment Aqueous solution. Résumé : Hydrothermally prepared mesoporous silica gel (prepared under acidic condition) was calcined at different temperatures to control concentration of surface hydroxyl groups. These materials were functionalized with 3-aminopropyltrimethoxysilane (APTMS) and used for the adsorption of Cu2+ ions. Adsorption isotherm and adsorption capacity of the amine functionalized materials for Cu2+ were followed by inductively coupled plasma optical emission spectrometry (ICP-OES). The adsorption capacity for functionalized silica gel was correlated with population density of hydroxyl groups and hence amine content in the materials, which was determined by CHN analysis. Nitrogen adsorption/desorption measurements at liquid N2 temperature, Fourier transform infrared spectrometry (FTIR), and 29Si MAS NMR spectra were used to follow the changes in the textural parameters and surface properties of the mesoporous silica gel samples. This study indicates that thermal treatment of silica gel determines the population density of surface hydroxyl groups and hence the NH2 population density after functionalization of the gels, which in turn determines the NH2/Cu2+ ratio at saturation of Cu2+ on the functionalized silica gel. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1007773 Exemplaires
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Titre : Sulfur pigments synthesized from zeolite LTA under vacuum and in Air. XRD and spectroscopic (UV−vis, FTIR, Raman, ESR, ESE) characterization Type de document : texte imprimé Auteurs : Stanisław K. Hoffmann, Auteur ; Janina Goslar, Auteur ; Stefan Lijewski, Auteur Année de publication : 2010 Article en page(s) : pp 8192–8199 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Sulfur Zeolite Spectroscopic. Résumé : X-ray, UV−vis, FT-infrared, Raman, continuous wave, and pulsed ESR spectroscopy were applied to characterize pigments prepared at 500 °C under vacuum or in air from mixtures of zeolite A (LTA) with sulfur (40 wt %) and anhydrous sodium sulfide (Na2/S = 0.1−0.4). The samples maintained the LTA structure. Sample color results from an S3− absorption band and the shoulder of a UV band. The fingerprint and asymmetric stretch region of the IR spectra show that the pigments synthesized in air have more disordered structures. The S2−/S3−ratio was estimated from Raman spectra. The ESR spectra of S3− radicals show the existence of several phases visible as five different ESR components. Two components dominate: ideal [Na4S3−]3+ clusters and clusters existing in a disordered environment. The samples synthesized in air show a substantial distortion of local structure. Synthesis in vacuum leads to products containing about 20% of the ordered crystalline phase. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100983m
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8192–8199[article] Sulfur pigments synthesized from zeolite LTA under vacuum and in Air. XRD and spectroscopic (UV−vis, FTIR, Raman, ESR, ESE) characterization [texte imprimé] / Stanisław K. Hoffmann, Auteur ; Janina Goslar, Auteur ; Stefan Lijewski, Auteur . - 2010 . - pp 8192–8199.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8192–8199
Mots-clés : Sulfur Zeolite Spectroscopic. Résumé : X-ray, UV−vis, FT-infrared, Raman, continuous wave, and pulsed ESR spectroscopy were applied to characterize pigments prepared at 500 °C under vacuum or in air from mixtures of zeolite A (LTA) with sulfur (40 wt %) and anhydrous sodium sulfide (Na2/S = 0.1−0.4). The samples maintained the LTA structure. Sample color results from an S3− absorption band and the shoulder of a UV band. The fingerprint and asymmetric stretch region of the IR spectra show that the pigments synthesized in air have more disordered structures. The S2−/S3−ratio was estimated from Raman spectra. The ESR spectra of S3− radicals show the existence of several phases visible as five different ESR components. Two components dominate: ideal [Na4S3−]3+ clusters and clusters existing in a disordered environment. The samples synthesized in air show a substantial distortion of local structure. Synthesis in vacuum leads to products containing about 20% of the ordered crystalline phase. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100983m Exemplaires
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Titre : Preparation of intumescent flame retardant poly(butylene succinate) using fumed silica as synergistic agent Type de document : texte imprimé Auteurs : Yangjuan Chen, Auteur ; Jing Zhan, Auteur ; Ping Zhang, Auteur Année de publication : 2010 Article en page(s) : pp 8200–8208 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Silica Synergistic agent. Résumé : A novel intumescent flame retardant (IFR) poly(butylene succinate) (PBS) with an antidripping property using fumed silica as a synergistic agent was prepared. Ammonium polyphosphate, melamine, and fumed silica were added in PBS via melt blending. It was revealed that the flame retardant PBS exhibited both excellent flame retardance and antidripping properties when the three components of IFR coexisted at an appropriate proportion. The lowest total loading of flame retardant could be reduced to 17 wt % with the synergism of fumed silica, for the goal of vertical flammability (UL-94) V-0 rate. Scanning electron microscopy and X-ray photoelectron spectroscopy were employed to characterize the morphology and composition of residual char, respectively. The combustion properties and thermal degradation behavior of the IFR-PBS composites were fully evaluated, and the possible flame retardant mechanism was proposed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100989j
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8200–8208[article] Preparation of intumescent flame retardant poly(butylene succinate) using fumed silica as synergistic agent [texte imprimé] / Yangjuan Chen, Auteur ; Jing Zhan, Auteur ; Ping Zhang, Auteur . - 2010 . - pp 8200–8208.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8200–8208
Mots-clés : Silica Synergistic agent. Résumé : A novel intumescent flame retardant (IFR) poly(butylene succinate) (PBS) with an antidripping property using fumed silica as a synergistic agent was prepared. Ammonium polyphosphate, melamine, and fumed silica were added in PBS via melt blending. It was revealed that the flame retardant PBS exhibited both excellent flame retardance and antidripping properties when the three components of IFR coexisted at an appropriate proportion. The lowest total loading of flame retardant could be reduced to 17 wt % with the synergism of fumed silica, for the goal of vertical flammability (UL-94) V-0 rate. Scanning electron microscopy and X-ray photoelectron spectroscopy were employed to characterize the morphology and composition of residual char, respectively. The combustion properties and thermal degradation behavior of the IFR-PBS composites were fully evaluated, and the possible flame retardant mechanism was proposed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100989j Exemplaires
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Titre : Simple nonlinear predictive control strategy for chemical processes using sparse kernel learning with polynomial form Type de document : texte imprimé Auteurs : Yi Liu, Auteur ; Yanchen Gao, Auteur ; Zengliang Gao, Auteur Année de publication : 2010 Article en page(s) : pp 8209–8218 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nonlinear predictive control Polynomial form. Résumé : A simple nonlinear control strategy using sparse kernel learning (SKL) with a polynomial kernel form is presented and applied to chemical processes. The nonlinear process is first identified by SKL with a polynomial kernel, and then a predictive control performance index is formulated. This index is characterized as an even-degree polynomial function of the manipulated input and has the benefit that the input can be separated from the index because of its special structure. Consequently, the optimal manipulated input can be efficiently obtained by solving a simple root problem of an odd-degree polynomial equation. Moreover, the control parameter directly relates to its performance and can be tuned in a guided manner. All these attributes result in a practicable solution for real-time process control. The novel controller is applied to two chemical processes to evaluate its performance. The obtained results show the superiority of the proposed method compared to a well-tuned proportional−integral−derivative controller in different situations. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901548u
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8209–8218[article] Simple nonlinear predictive control strategy for chemical processes using sparse kernel learning with polynomial form [texte imprimé] / Yi Liu, Auteur ; Yanchen Gao, Auteur ; Zengliang Gao, Auteur . - 2010 . - pp 8209–8218.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8209–8218
Mots-clés : Nonlinear predictive control Polynomial form. Résumé : A simple nonlinear control strategy using sparse kernel learning (SKL) with a polynomial kernel form is presented and applied to chemical processes. The nonlinear process is first identified by SKL with a polynomial kernel, and then a predictive control performance index is formulated. This index is characterized as an even-degree polynomial function of the manipulated input and has the benefit that the input can be separated from the index because of its special structure. Consequently, the optimal manipulated input can be efficiently obtained by solving a simple root problem of an odd-degree polynomial equation. Moreover, the control parameter directly relates to its performance and can be tuned in a guided manner. All these attributes result in a practicable solution for real-time process control. The novel controller is applied to two chemical processes to evaluate its performance. The obtained results show the superiority of the proposed method compared to a well-tuned proportional−integral−derivative controller in different situations. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901548u Exemplaires
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Titre : Synthesis of unloading operation procedure for a mixed operation of above-ground and in-ground liquefied natural gas storage tanks using dynamic simulation Type de document : texte imprimé Auteurs : Chul-Jin Lee, Auteur ; Youngsub Lim, Auteur ; Chansaem Park, Auteur Année de publication : 2010 Article en page(s) : pp 8219–8226 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Liquefied natural gas Dynamic simulation. Résumé : Because of increased liquefied natural gas (LNG) demand, operation of LNG receiving terminals having both above-ground and in-ground LNG storage tanks will soon be required. In such cases, there exists a pressure head difference between the two types of tanks. As such, during the depressurization step of LNG unloading, vapor can be generated at the top of the unloading pipeline of the above-ground tank due to pressure head. Vapor produced in a branch pipeline of the above-ground tank can thereby cause congestion during depressurization, resulting in a pressure difference across the unloading valve. This can, in turn, cause excessive boil off gas inflow into the storage tank. In this paper, we suggest a reliable unloading operation procedure for a mixed operation of above-ground and in-ground storage tanks using dynamic simulation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902075k
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8219–8226[article] Synthesis of unloading operation procedure for a mixed operation of above-ground and in-ground liquefied natural gas storage tanks using dynamic simulation [texte imprimé] / Chul-Jin Lee, Auteur ; Youngsub Lim, Auteur ; Chansaem Park, Auteur . - 2010 . - pp 8219–8226.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8219–8226
Mots-clés : Liquefied natural gas Dynamic simulation. Résumé : Because of increased liquefied natural gas (LNG) demand, operation of LNG receiving terminals having both above-ground and in-ground LNG storage tanks will soon be required. In such cases, there exists a pressure head difference between the two types of tanks. As such, during the depressurization step of LNG unloading, vapor can be generated at the top of the unloading pipeline of the above-ground tank due to pressure head. Vapor produced in a branch pipeline of the above-ground tank can thereby cause congestion during depressurization, resulting in a pressure difference across the unloading valve. This can, in turn, cause excessive boil off gas inflow into the storage tank. In this paper, we suggest a reliable unloading operation procedure for a mixed operation of above-ground and in-ground storage tanks using dynamic simulation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902075k Exemplaires
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Titre : Classification of chemical processes: a graphical approach to process synthesis to improve reactive process work efficiency Type de document : texte imprimé Auteurs : Baraka Celestin Sempuga, Auteur ; Brendon Hausberger, Auteur ; Bilal Patel, Auteur Année de publication : 2010 Article en page(s) : pp 8227–8237 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Chemical processes Process work efficiency. Résumé : To reduce carbon dioxide emissions for chemical processes, one should make them as reversible as possible. Patel et al. [Ind. Eng. Chem. Res. 2005, 44, 3529−3537] showed that, in some cases, one can analyze processes in terms of their work and heat requirements. In particular, for processes, there exists a temperature that is called “the Carnot temperature”, at which one can satisfy the work requirement for the process, using the heat that must be added or removed. The analogy of a heat engine and Carnot temperature is applied to chemical processes, particularly on reactive processes, using a graphical approach. This approach looks at chemical processes holistically, where only the inlet and outlet streams are considered. The process is represented in a ΔH−ΔG space. Chemical processes are classified in different thermodynamics regions as defined in the ΔH−ΔG space, and their feasibility in terms of heat and work requirement is discussed. This approach allows one to determine whether heat at an appropriate temperature is sufficient to meet the work requirement of a chemical process, or if other means should be considered. The approach is used to investigate and discuss the possibility of combining reactive chemical processes classified in different thermodynamic regions in the ΔH−ΔG space, with the purpose of making infeasible processes possible, or to minimize, or even eliminate, the work requirement of the combined process. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100288h
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8227–8237[article] Classification of chemical processes: a graphical approach to process synthesis to improve reactive process work efficiency [texte imprimé] / Baraka Celestin Sempuga, Auteur ; Brendon Hausberger, Auteur ; Bilal Patel, Auteur . - 2010 . - pp 8227–8237.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8227–8237
Mots-clés : Chemical processes Process work efficiency. Résumé : To reduce carbon dioxide emissions for chemical processes, one should make them as reversible as possible. Patel et al. [Ind. Eng. Chem. Res. 2005, 44, 3529−3537] showed that, in some cases, one can analyze processes in terms of their work and heat requirements. In particular, for processes, there exists a temperature that is called “the Carnot temperature”, at which one can satisfy the work requirement for the process, using the heat that must be added or removed. The analogy of a heat engine and Carnot temperature is applied to chemical processes, particularly on reactive processes, using a graphical approach. This approach looks at chemical processes holistically, where only the inlet and outlet streams are considered. The process is represented in a ΔH−ΔG space. Chemical processes are classified in different thermodynamics regions as defined in the ΔH−ΔG space, and their feasibility in terms of heat and work requirement is discussed. This approach allows one to determine whether heat at an appropriate temperature is sufficient to meet the work requirement of a chemical process, or if other means should be considered. The approach is used to investigate and discuss the possibility of combining reactive chemical processes classified in different thermodynamic regions in the ΔH−ΔG space, with the purpose of making infeasible processes possible, or to minimize, or even eliminate, the work requirement of the combined process. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100288h Exemplaires
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Titre : Theoretical and experimental study of lactic acid stripping from loaded organic phase Type de document : texte imprimé Auteurs : G. Kyuchoukov, Auteur ; D. Yankov, Auteur Année de publication : 2010 Article en page(s) : pp 8238–8243 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Lactic acid Organic phase. Résumé : The process of stripping lactic acid with different stripping agents was investigated for two organic-phase systems containing trioctylamine (TOA). On the basis of theoretical considerations for extraction mechanism, equations for stripping were developed. The theoretical values of the extent of stripping and the concentrations of lactic acid in organic and aqueous phases were compared with experimental values in the cases of water, NaOH, NaCl, HCl, and carbonates as the stripping agents. The possibilities of repeated use of the extractants in extraction/stripping runs were investigated. The best results were obtained with a system containing 20% TOA, 30% dodecane, and 50% decanol with (NH4)HCO3 as the stripping agent. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100914n
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8238–8243[article] Theoretical and experimental study of lactic acid stripping from loaded organic phase [texte imprimé] / G. Kyuchoukov, Auteur ; D. Yankov, Auteur . - 2010 . - pp 8238–8243.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8238–8243
Mots-clés : Lactic acid Organic phase. Résumé : The process of stripping lactic acid with different stripping agents was investigated for two organic-phase systems containing trioctylamine (TOA). On the basis of theoretical considerations for extraction mechanism, equations for stripping were developed. The theoretical values of the extent of stripping and the concentrations of lactic acid in organic and aqueous phases were compared with experimental values in the cases of water, NaOH, NaCl, HCl, and carbonates as the stripping agents. The possibilities of repeated use of the extractants in extraction/stripping runs were investigated. The best results were obtained with a system containing 20% TOA, 30% dodecane, and 50% decanol with (NH4)HCO3 as the stripping agent. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100914n Exemplaires
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Titre : Isopiestic study of the Na2CrO4−H2O system at 353.15 K: prediction of the solubility of Na2CrO4 in aqueous NaOH solutions Type de document : texte imprimé Auteurs : Wei Jin, Auteur ; Shili Zheng, Auteur ; Hao Du, Auteur Année de publication : 2010 Article en page(s) : pp 8244–8247 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Isopiestic study Aqueous solutions. Résumé : The osmotic coefficients of the Na2CrO4−H2O system at 353.15 K were determined using isopiestic method ranging from 0.05 to 7.683 mol·kg−1. The experimental osmotic coefficients were excellently correlated with Pitzer equation to obtain the interaction parameters, the activity coefficients, and the solubility product for Na2CrO4. Furthermore, the solubility of Na2CrO4 in NaOH solutions at 353.15 K was predicted using binary parameters, and the predicted values agree with the experimental data, demonstrating the Pitzer equation is capable of optimizing the processes for the removal and recovery of sodium chromate in NaOH solutions at high temperature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1011068
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8244–8247[article] Isopiestic study of the Na2CrO4−H2O system at 353.15 K: prediction of the solubility of Na2CrO4 in aqueous NaOH solutions [texte imprimé] / Wei Jin, Auteur ; Shili Zheng, Auteur ; Hao Du, Auteur . - 2010 . - pp 8244–8247.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8244–8247
Mots-clés : Isopiestic study Aqueous solutions. Résumé : The osmotic coefficients of the Na2CrO4−H2O system at 353.15 K were determined using isopiestic method ranging from 0.05 to 7.683 mol·kg−1. The experimental osmotic coefficients were excellently correlated with Pitzer equation to obtain the interaction parameters, the activity coefficients, and the solubility product for Na2CrO4. Furthermore, the solubility of Na2CrO4 in NaOH solutions at 353.15 K was predicted using binary parameters, and the predicted values agree with the experimental data, demonstrating the Pitzer equation is capable of optimizing the processes for the removal and recovery of sodium chromate in NaOH solutions at high temperature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1011068 Exemplaires
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Titre : Discrete solution of the breakage equation using markov chains Type de document : texte imprimé Auteurs : Muammer Catak, Auteur ; Nursin Bas, Auteur ; Kevin Cronin, Auteur Année de publication : 2010 Article en page(s) : pp 8248–8257 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Markov chains Breakage equation. Résumé : Analytical solution of population balance equations (PBEs) may be impossible except for some simple cases. In the literature there are a number of methods to solve PBEs including discrete methods, Monte Carlo simulation, and method of moments. In this paper, the Markov chain is presented as a discrete solution for a population balance equation of a breakage process for determining the particle size distribution (PSD) over time. The transition matrix P, which is the key operator of a Markov chain, is built using breakage equations. Thereafter, from calculating transition matrix, P, the particle size distribution of the system is easily evaluated using the Markov chain. According to simulation results, if the size range of the system is divided into a sufficient number of states and an appropriate transition time step was chosen, then results from the Markov chain are in agreement with the analytical solution of PBEs governed by the same breakage functions. In addition to theoretical illustration, the Markov theory was employed to model the breakage process of aggregated food products passing through a pneumatic conveying pipeline rig. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100216g
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8248–8257[article] Discrete solution of the breakage equation using markov chains [texte imprimé] / Muammer Catak, Auteur ; Nursin Bas, Auteur ; Kevin Cronin, Auteur . - 2010 . - pp 8248–8257.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8248–8257
Mots-clés : Markov chains Breakage equation. Résumé : Analytical solution of population balance equations (PBEs) may be impossible except for some simple cases. In the literature there are a number of methods to solve PBEs including discrete methods, Monte Carlo simulation, and method of moments. In this paper, the Markov chain is presented as a discrete solution for a population balance equation of a breakage process for determining the particle size distribution (PSD) over time. The transition matrix P, which is the key operator of a Markov chain, is built using breakage equations. Thereafter, from calculating transition matrix, P, the particle size distribution of the system is easily evaluated using the Markov chain. According to simulation results, if the size range of the system is divided into a sufficient number of states and an appropriate transition time step was chosen, then results from the Markov chain are in agreement with the analytical solution of PBEs governed by the same breakage functions. In addition to theoretical illustration, the Markov theory was employed to model the breakage process of aggregated food products passing through a pneumatic conveying pipeline rig. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100216g Exemplaires
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Titre : Evaluation of Mountain beetle-infested lodgepole pine for cellulosic ethanol production by sulfite pretreatment to overcome recalcitrance of lignocellulose Type de document : texte imprimé Auteurs : X. Luo, Auteur ; R. Gleisner, Auteur ; S. Tian, Auteur Année de publication : 2010 Article en page(s) : pp 8258–8266 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ethanol Sulfite pretreatment Lignocellulose. Résumé : The potentials of deteriorated mountain pine beetle (Dendroctonus ponderosae)-killed lodgepole pine (Pinus contorta) trees for cellulosic ethanol production were evaluated using the sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) process. The trees were harvested from two sites in the United States Arapaho-Roosevelt National Forest, Colorado. The infestation age of the trees varied from zero to about 8 years. Mild (170 °C) and harsh (180 °C) SPORL pretreatments were conducted. The chemical charges were sulfuric acid of 2.21% and sodium bisulfite of 8% on oven dry wood for the harsh and half of those for the mild pretreatment. The results suggest that beetle-caused mortality enriched glucan content by as much as 3 percentage points (or 7.5%) in wood. The glucan enrichment seems to increase with infestation age. The enriched glucan can be captured after SPORL pretreatment followed by enzymatic hydrolysis. The killed trees are more susceptible to SPORL pretreatment, which enhanced substrate enzymatic digestibility (SED). Enzymatic hydrolysis glucose yields (EHGY) from killed trees were about 5−20% higher than those from their corresponding live trees. Total fermentable sugar productions from dead trees (including a tree laying on the ground) were 4−14% higher than corresponding production from live trees, depending on pretreatment conditions and infestation age. An ethanol yield of 267 L/metric ton of wood or 69% theoretical value was achieved from a tree infested 4 years, 7% higher than the 250 L/metric ton of wood from the corresponding live tree. The results also demonstrated the robustness of SPORL pretreatment for lodgepole pine. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1003202
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8258–8266[article] Evaluation of Mountain beetle-infested lodgepole pine for cellulosic ethanol production by sulfite pretreatment to overcome recalcitrance of lignocellulose [texte imprimé] / X. Luo, Auteur ; R. Gleisner, Auteur ; S. Tian, Auteur . - 2010 . - pp 8258–8266.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8258–8266
Mots-clés : Ethanol Sulfite pretreatment Lignocellulose. Résumé : The potentials of deteriorated mountain pine beetle (Dendroctonus ponderosae)-killed lodgepole pine (Pinus contorta) trees for cellulosic ethanol production were evaluated using the sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) process. The trees were harvested from two sites in the United States Arapaho-Roosevelt National Forest, Colorado. The infestation age of the trees varied from zero to about 8 years. Mild (170 °C) and harsh (180 °C) SPORL pretreatments were conducted. The chemical charges were sulfuric acid of 2.21% and sodium bisulfite of 8% on oven dry wood for the harsh and half of those for the mild pretreatment. The results suggest that beetle-caused mortality enriched glucan content by as much as 3 percentage points (or 7.5%) in wood. The glucan enrichment seems to increase with infestation age. The enriched glucan can be captured after SPORL pretreatment followed by enzymatic hydrolysis. The killed trees are more susceptible to SPORL pretreatment, which enhanced substrate enzymatic digestibility (SED). Enzymatic hydrolysis glucose yields (EHGY) from killed trees were about 5−20% higher than those from their corresponding live trees. Total fermentable sugar productions from dead trees (including a tree laying on the ground) were 4−14% higher than corresponding production from live trees, depending on pretreatment conditions and infestation age. An ethanol yield of 267 L/metric ton of wood or 69% theoretical value was achieved from a tree infested 4 years, 7% higher than the 250 L/metric ton of wood from the corresponding live tree. The results also demonstrated the robustness of SPORL pretreatment for lodgepole pine. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1003202 Exemplaires
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Titre : Methane enclathration with sodium dodecyl sulfate: effect of cyclopentane and two salts on formation kinetics Type de document : texte imprimé Auteurs : Junshe S. Zhang, Auteur ; Jo A. Salera, Auteur ; Jae W. Lee, Auteur Année de publication : 2010 Article en page(s) : pp 8267–8270 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Methane Sodium Dodecyl Kinetics. Résumé : This work presents the effect of NaCl and NaClO4 on the kinetics of methane enclathration with cyclopentane (CP) and sodium dodecyl sulfate (SDS) in a nonstirred batch reactor. Methane and 1 cm3 of CP were charged sequentially to 150 cm3 of solutions in a high-pressure vessel and the reaction system was cooled down to 274.6 K with an initial pressure of 7.1 MPa. Hydrates are visually observed within 1 h after the onset of cooling at a SDS concentration range of 0−200 ppm. At the end of a growth period of 2.5 h, the pressure reduces to 6.4 MPa for SDS concentrations below 20 ppm, whereas it decreases to 3.2 MPa for SDS concentrations above 50 ppm without any salts, which is very close to the hydrate equilibrium pressure. With 20 ppm SDS and 1 cm3 of CP, the average enclathration rate maximizes at 1.0 mM NaCl or 5.0 mM NaClO4 as the salt concentration increases from 0 to 100 mM. However, with 100 ppm SDS, it decreases monotonically with the increased salt concentration. These results not only provide an implication of reducing the SDS dosage (down to 50 ppm or less) in regard to fast enclathration but also further our understanding of the promoting role of surfactants. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100759p
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8267–8270[article] Methane enclathration with sodium dodecyl sulfate: effect of cyclopentane and two salts on formation kinetics [texte imprimé] / Junshe S. Zhang, Auteur ; Jo A. Salera, Auteur ; Jae W. Lee, Auteur . - 2010 . - pp 8267–8270.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8267–8270
Mots-clés : Methane Sodium Dodecyl Kinetics. Résumé : This work presents the effect of NaCl and NaClO4 on the kinetics of methane enclathration with cyclopentane (CP) and sodium dodecyl sulfate (SDS) in a nonstirred batch reactor. Methane and 1 cm3 of CP were charged sequentially to 150 cm3 of solutions in a high-pressure vessel and the reaction system was cooled down to 274.6 K with an initial pressure of 7.1 MPa. Hydrates are visually observed within 1 h after the onset of cooling at a SDS concentration range of 0−200 ppm. At the end of a growth period of 2.5 h, the pressure reduces to 6.4 MPa for SDS concentrations below 20 ppm, whereas it decreases to 3.2 MPa for SDS concentrations above 50 ppm without any salts, which is very close to the hydrate equilibrium pressure. With 20 ppm SDS and 1 cm3 of CP, the average enclathration rate maximizes at 1.0 mM NaCl or 5.0 mM NaClO4 as the salt concentration increases from 0 to 100 mM. However, with 100 ppm SDS, it decreases monotonically with the increased salt concentration. These results not only provide an implication of reducing the SDS dosage (down to 50 ppm or less) in regard to fast enclathration but also further our understanding of the promoting role of surfactants. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100759p Exemplaires
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Titre : Coarse-grained model for perfluorocarbons and phase equilibrium simulation of perfluorocarbons/CO2 mixtures Type de document : texte imprimé Auteurs : Qiu Du, Auteur ; Zhen Yang, Auteur ; Nannan Yang, Auteur Année de publication : 2010 Article en page(s) : pp 8271–8278 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Perfluorocarbons Phase equilibrium. Résumé : A coarse-grained (CG) model for perfluorocarbons (PFCs) with arbitrary chain length has been established in this work. The construction of the CG model is based on the all-atomic (AA) simulation results and the thermodynamics experimental data. The intramolecular parameters are obtained through reproducing the intramolecular bond and angle distributions from AA simulations. The intermolecular parameters are determined by fitting the experimental bulk densities and surface tensions. Comparison between the CG and AA simulations has confirmed that the CG model can reasonably represent the structure behavior of PFCs. Furthermore, the CG model has been also extended to simulate the vapor−liquid phase equilibria for the mixture of PFCs and carbon dioxide by using the Gibbs ensemble Monte Carlo (GEMC) method. As compared with the experimental data, the GEMC simulation based on the CG model satisfactorily reproduces the mixture phase equilibria. The developed CG model will be useful in simulating the self-assembly of PFC-based surfactants/blockpolymers in supercritical carbon dioxide fluid. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100935u
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8271–8278[article] Coarse-grained model for perfluorocarbons and phase equilibrium simulation of perfluorocarbons/CO2 mixtures [texte imprimé] / Qiu Du, Auteur ; Zhen Yang, Auteur ; Nannan Yang, Auteur . - 2010 . - pp 8271–8278.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8271–8278
Mots-clés : Perfluorocarbons Phase equilibrium. Résumé : A coarse-grained (CG) model for perfluorocarbons (PFCs) with arbitrary chain length has been established in this work. The construction of the CG model is based on the all-atomic (AA) simulation results and the thermodynamics experimental data. The intramolecular parameters are obtained through reproducing the intramolecular bond and angle distributions from AA simulations. The intermolecular parameters are determined by fitting the experimental bulk densities and surface tensions. Comparison between the CG and AA simulations has confirmed that the CG model can reasonably represent the structure behavior of PFCs. Furthermore, the CG model has been also extended to simulate the vapor−liquid phase equilibria for the mixture of PFCs and carbon dioxide by using the Gibbs ensemble Monte Carlo (GEMC) method. As compared with the experimental data, the GEMC simulation based on the CG model satisfactorily reproduces the mixture phase equilibria. The developed CG model will be useful in simulating the self-assembly of PFC-based surfactants/blockpolymers in supercritical carbon dioxide fluid. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100935u Exemplaires
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Titre : Content increase of spirostanol saponins during enzymatic hydrolysis of dioscorea zingiberensis C. H. wright Type de document : texte imprimé Auteurs : Yue’e Peng, Auteur ; Yanxin Wang, Auteur ; Zhihua Yang, Auteur Année de publication : 2010 Article en page(s) : pp 8279–8281 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Enzymatic Hydrolysis Spirostanol. Résumé : Dioscorea zingiberensis C. H. Wright (DZW) has been used as a traditional Chinese medicinal plant for the extraction of diosgenin, which is a starting material for the semisynthesis of drugs of steroidal hormones such as progesterone and testosterone. In this study, the changes in contents of three spirostanol saponins, i.e., zingiberensis newsaponin, deltonin, and prosapogenin A of dioscin, during enzymatic hydrolysis of DZW were monitored. The results show that xylanase leads to a 212% increase in the content of spirostanol saponins, as compared with that in the raw DZW rhizome, while the other three enzymes induced an 22% increase. Therefore, xylanase hydrolysis of DZW would be a promising approach to enhance the content of spirostanol saponins, as well as the diosgenin yield. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1001923
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8279–8281[article] Content increase of spirostanol saponins during enzymatic hydrolysis of dioscorea zingiberensis C. H. wright [texte imprimé] / Yue’e Peng, Auteur ; Yanxin Wang, Auteur ; Zhihua Yang, Auteur . - 2010 . - pp 8279–8281.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8279–8281
Mots-clés : Enzymatic Hydrolysis Spirostanol. Résumé : Dioscorea zingiberensis C. H. Wright (DZW) has been used as a traditional Chinese medicinal plant for the extraction of diosgenin, which is a starting material for the semisynthesis of drugs of steroidal hormones such as progesterone and testosterone. In this study, the changes in contents of three spirostanol saponins, i.e., zingiberensis newsaponin, deltonin, and prosapogenin A of dioscin, during enzymatic hydrolysis of DZW were monitored. The results show that xylanase leads to a 212% increase in the content of spirostanol saponins, as compared with that in the raw DZW rhizome, while the other three enzymes induced an 22% increase. Therefore, xylanase hydrolysis of DZW would be a promising approach to enhance the content of spirostanol saponins, as well as the diosgenin yield. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1001923 Exemplaires
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