Dépouillements

Commentary / Stuart W. Churchill in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8806–8816 Titre : Commentary : the state of the art of education in reaction engineering Type de document : texte imprimé Auteurs : Stuart W. Churchill, Auteur Année de publication : 2011 Article en page(s) : pp. 8806–8816 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Reaction engineering Résumé : An informal survey of recent archival publications indicates that academic and industrial research in reaction engineering are interconnected, and they keep pace with those in the other engineering sciences, with one exception: the textbooks on reaction engineering incorporate many obsolete concepts, neglect some of the advances, and focus on the solution of overly simplified models. It is presumed that these characteristics carry over to the classroom. This is a serious matter, because chemical engineers, throughout their careers, are apt to cling to the concepts and textbooks that they acquire while in school. The simplest and perhaps most effective corrective for these shortcomings is the distribution of electronic supplements by the teacher. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200907s [article] Commentary : the state of the art of education in reaction engineering [texte imprimé] / Stuart W. Churchill, Auteur . - 2011 . - pp. 8806–8816. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8806–8816 Mots-clés : Reaction engineering Résumé : An informal survey of recent archival publications indicates that academic and industrial research in reaction engineering are interconnected, and they keep pace with those in the other engineering sciences, with one exception: the textbooks on reaction engineering incorporate many obsolete concepts, neglect some of the advances, and focus on the solution of overly simplified models. It is presumed that these characteristics carry over to the classroom. This is a serious matter, because chemical engineers, throughout their careers, are apt to cling to the concepts and textbooks that they acquire while in school. The simplest and perhaps most effective corrective for these shortcomings is the distribution of electronic supplements by the teacher. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200907s

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On the gradient diffusion hypothesis and passive scalar transport in turbulent flows / Daniel P. Combest in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8817–8823 Titre : On the gradient diffusion hypothesis and passive scalar transport in turbulent flows Type de document : texte imprimé Auteurs : Daniel P. Combest, Auteur ; Palghat A. Ramachandran, Auteur ; Milorad P. Dudukovic, Auteur Année de publication : 2011 Article en page(s) : pp. 8817–8823 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Turbulent flow Transport process Diffusion Résumé : A discussion of modeling passive scalar transport in turbulent flows is given. Several methods employed to dose the scalar-flux term ⟨u'φ'⟩ that arises during Reynolds averaging are provided. Alternatives and improvements to the gradient diffusion hypotheses are addressed, most notably, the need for an alternative to the global constant turbulent Schmidt and Prandtl numbers. The reader is given a brief history covering methods used to predict turbulent Schmidt and Prandtl numbers, along with recommendations for future research, based partially on studies by Professor Stuart Churchill. More detailed formulations of turbulent Schmidt or Prandtl numbers will enable better approximations of the influence of turbulence in models of passive scalar flows using the gradient diffusion hypothesis. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395827 [article] On the gradient diffusion hypothesis and passive scalar transport in turbulent flows [texte imprimé] / Daniel P. Combest, Auteur ; Palghat A. Ramachandran, Auteur ; Milorad P. Dudukovic, Auteur . - 2011 . - pp. 8817–8823. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8817–8823 Mots-clés : Turbulent flow Transport process Diffusion Résumé : A discussion of modeling passive scalar transport in turbulent flows is given. Several methods employed to dose the scalar-flux term ⟨u'φ'⟩ that arises during Reynolds averaging are provided. Alternatives and improvements to the gradient diffusion hypotheses are addressed, most notably, the need for an alternative to the global constant turbulent Schmidt and Prandtl numbers. The reader is given a brief history covering methods used to predict turbulent Schmidt and Prandtl numbers, along with recommendations for future research, based partially on studies by Professor Stuart Churchill. More detailed formulations of turbulent Schmidt or Prandtl numbers will enable better approximations of the influence of turbulence in models of passive scalar flows using the gradient diffusion hypothesis. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395827

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A comparison of ammonia borane dehydrogenation methods for proton-exchange-membrane fuel cell vehicles / Ahmad Al-Kukhun in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8824-8835 Titre : A comparison of ammonia borane dehydrogenation methods for proton-exchange-membrane fuel cell vehicles : hydrogen yield and ammonia formation and Its removal Type de document : texte imprimé Auteurs : Ahmad Al-Kukhun, Auteur ; Hyun Tae Hwang, Auteur ; Arvind Varma, Auteur Année de publication : 2011 Article en page(s) : pp. 8824-8835 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Proton exchange membrane fuel cells Dehydrogenation Résumé : Current promising methods to release hydrogen from ammonia borane (NH3BH3, AB; 19.6 wt % H2) including neat thermolysis, thermolysis in ionic liquid bmimCl with or without proton sponge, thermolysis with nano-BN and hydrothermolysis, were investigated for hydrogen yield and ammonia formation. It was found that even trace moisture influences AB dehydrogenation significantly. The hydrothermolysis at 85 °C (13.5 wt % H2, 1 mol % NH3) and thermolysis in bmimCl with 3 wt % moisture at 110 °C (13 wt % H2, 0.2 mol % NH3) methods were found to be the most promising. Since the target for a proton exchange membrane (PEM) fuel cell is an ammonia concentration less than 0.1 ppm, different purification methods were evaluated. Using experiments and simulations, the proposed ammonia removal method, involving absorption in water followed by adsorption on carbon, was optimized and tested. This study demonstrates that, with high hydrogen yield and an effective method to remove ammonia and borazine, AB dehydrogenation is an attractive approach to generate hydrogen for PEM fuel cell vehicle applications. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395828 [article] A comparison of ammonia borane dehydrogenation methods for proton-exchange-membrane fuel cell vehicles : hydrogen yield and ammonia formation and Its removal [texte imprimé] / Ahmad Al-Kukhun, Auteur ; Hyun Tae Hwang, Auteur ; Arvind Varma, Auteur . - 2011 . - pp. 8824-8835. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8824-8835 Mots-clés : Proton exchange membrane fuel cells Dehydrogenation Résumé : Current promising methods to release hydrogen from ammonia borane (NH3BH3, AB; 19.6 wt % H2) including neat thermolysis, thermolysis in ionic liquid bmimCl with or without proton sponge, thermolysis with nano-BN and hydrothermolysis, were investigated for hydrogen yield and ammonia formation. It was found that even trace moisture influences AB dehydrogenation significantly. The hydrothermolysis at 85 °C (13.5 wt % H2, 1 mol % NH3) and thermolysis in bmimCl with 3 wt % moisture at 110 °C (13 wt % H2, 0.2 mol % NH3) methods were found to be the most promising. Since the target for a proton exchange membrane (PEM) fuel cell is an ammonia concentration less than 0.1 ppm, different purification methods were evaluated. Using experiments and simulations, the proposed ammonia removal method, involving absorption in water followed by adsorption on carbon, was optimized and tested. This study demonstrates that, with high hydrogen yield and an effective method to remove ammonia and borazine, AB dehydrogenation is an attractive approach to generate hydrogen for PEM fuel cell vehicle applications. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395828

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Stochastic modeling for the formation of activated carbons / L. T. Fan in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8836–8841 Titre : Stochastic modeling for the formation of activated carbons : nonlinear approach Type de document : texte imprimé Auteurs : L. T. Fan, Auteur ; Andres Argoti, Auteur Année de publication : 2011 Article en page(s) : pp. 8836–8841 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Activated carbons Résumé : Activated carbons (ACs) have been widely deployed in the purification of gases and liquids or the separation of their mixtures. The formation of ACs entails the modification of the original internal surfaces of carbonaceous substrates, for example, coal or biomass, which can be effected by a variety of chemical or physical methods, thereby augmenting the carbonaceous substrates’ adsorbing capacities. The formation of ACs tends to proceed randomly or stochastically in view of the discrete and mesoscopic nature of the carbonaceous substrates, as well as the random encounters between the activation agent and carbon on the carbonaceous substrates’ internal surfaces; in addition, the carbonaceous substrates’ internal surfaces exhibit an intricate morphology or structure. Naturally, these traits of the formation of ACs render the process to vary incessantly with time. Thus, it is highly desirable that the analysis, modeling, and simulation of the formation of ACs from carbonaceous substrates be performed in light of a stochastic paradigm. Herein, a stochastic model for the formation of ACs is formulated as a pure-death process based on a nonlinear intensity of transition. The model gives rise to the process’ nonlinear master equation whose solution is obtained by resorting to a rational approximation method, the system-size expansion. This solution renders it possible to compute the mean as well as higher moments about this mean, for example, variance or standard deviation, which reveal and quantify the process’ inherent fluctuations. The results of modeling are validated by comparing them with the available experimental data. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102247z [article] Stochastic modeling for the formation of activated carbons : nonlinear approach [texte imprimé] / L. T. Fan, Auteur ; Andres Argoti, Auteur . - 2011 . - pp. 8836–8841. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8836–8841 Mots-clés : Activated carbons Résumé : Activated carbons (ACs) have been widely deployed in the purification of gases and liquids or the separation of their mixtures. The formation of ACs entails the modification of the original internal surfaces of carbonaceous substrates, for example, coal or biomass, which can be effected by a variety of chemical or physical methods, thereby augmenting the carbonaceous substrates’ adsorbing capacities. The formation of ACs tends to proceed randomly or stochastically in view of the discrete and mesoscopic nature of the carbonaceous substrates, as well as the random encounters between the activation agent and carbon on the carbonaceous substrates’ internal surfaces; in addition, the carbonaceous substrates’ internal surfaces exhibit an intricate morphology or structure. Naturally, these traits of the formation of ACs render the process to vary incessantly with time. Thus, it is highly desirable that the analysis, modeling, and simulation of the formation of ACs from carbonaceous substrates be performed in light of a stochastic paradigm. Herein, a stochastic model for the formation of ACs is formulated as a pure-death process based on a nonlinear intensity of transition. The model gives rise to the process’ nonlinear master equation whose solution is obtained by resorting to a rational approximation method, the system-size expansion. This solution renders it possible to compute the mean as well as higher moments about this mean, for example, variance or standard deviation, which reveal and quantify the process’ inherent fluctuations. The results of modeling are validated by comparing them with the available experimental data. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102247z

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Helical and Lemniscate Tubular Reactors / Charles G. Slominski in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8842–8850 Titre : Helical and Lemniscate Tubular Reactors Type de document : texte imprimé Auteurs : Charles G. Slominski, Auteur ; Warren D. Seider, Auteur ; Stuart W. Churchill, Auteur Année de publication : 2011 Article en page(s) : pp. 8842–8850 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Tubular reactor Résumé : Introducing curvature in a tubular reactor generates a secondary fluid motion that decreases the variance of the residence-time-distribution of the fluid elements. The conversion is thereby increased with respect to that of a straight tube, and in the extreme approaches the maximum corresponding to perfect radial mixing, which is the same as that for the hypothetical case of plug flow. Helically coiled tubes are widely used as reactors in industry, but experimental data and theoretical solutions are limited in number and scope. The fluid motion and conversion as determined by finite-element solutions using COMSOL is delineated more clearly than in prior studies for helical tubes and is also applied for a lemniscate tube (a figure-eight shape). Coiled tubes, lemniscate tubes, and other such configurations are designed to decrease the variance of the residence-time distribution of the fluid elements at the expense of a minimal increase in the pressure drop. The decrease in the variance of the residence-time distribution results in a reduction in the reactor length for a specified chemical conversion and thus in the floor space required to achieve a particular conversion. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395830 [article] Helical and Lemniscate Tubular Reactors [texte imprimé] / Charles G. Slominski, Auteur ; Warren D. Seider, Auteur ; Stuart W. Churchill, Auteur . - 2011 . - pp. 8842–8850. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8842–8850 Mots-clés : Tubular reactor Résumé : Introducing curvature in a tubular reactor generates a secondary fluid motion that decreases the variance of the residence-time-distribution of the fluid elements. The conversion is thereby increased with respect to that of a straight tube, and in the extreme approaches the maximum corresponding to perfect radial mixing, which is the same as that for the hypothetical case of plug flow. Helically coiled tubes are widely used as reactors in industry, but experimental data and theoretical solutions are limited in number and scope. The fluid motion and conversion as determined by finite-element solutions using COMSOL is delineated more clearly than in prior studies for helical tubes and is also applied for a lemniscate tube (a figure-eight shape). Coiled tubes, lemniscate tubes, and other such configurations are designed to decrease the variance of the residence-time distribution of the fluid elements at the expense of a minimal increase in the pressure drop. The decrease in the variance of the residence-time distribution results in a reduction in the reactor length for a specified chemical conversion and thus in the floor space required to achieve a particular conversion. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395830

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Polyelectrolyte multilayer stamping in aqueous phase and non-contact mode / Sumit Mehrotra in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp 8851–8858 Titre : Polyelectrolyte multilayer stamping in aqueous phase and non-contact mode Type de document : texte imprimé Auteurs : Sumit Mehrotra, Auteur ; Ilsoon Lee, Auteur ; Chun Liu, Auteur Année de publication : 2011 Article en page(s) : pp 8851–8858 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Polyelectrolyte Aqueous phase Résumé : Polyelectrolyte multilayer (PEM) transfer printing has been previously achieved by stamping under dry conditions. Here, we show for the first time that PEM can be transferred from a stamp to the base substrate under aqueous conditions whereby the two surfaces are in a noncontact mode. Degradable multilayers of (PAA/PEG)10.5 followed by nondegradable multilayers of (PDAC/SPS)80.5 were fabricated under acidic pH conditions on either PDMS or glass (stamp), and subsequently transferred over top of another multilayer prepared on a different substrate (base substrate), with a spacing of 200 μm between the stamping surface and the base substrate. This multilayer transfer was performed under physiological pH conditions. This process is referred to herein as noncontact, aqueous-phase multilayer (NAM) transfer. NAM transfer can be useful for applications such as fabricating three-dimensional (3-D) cellular scaffolds. We attempted to create a 3-D cellular scaffold using NAM transfer, and characterized the scaffolds with conventional and fluorescence microscopy. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102011m [article] Polyelectrolyte multilayer stamping in aqueous phase and non-contact mode [texte imprimé] / Sumit Mehrotra, Auteur ; Ilsoon Lee, Auteur ; Chun Liu, Auteur . - 2011 . - pp 8851–8858. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp 8851–8858 Mots-clés : Polyelectrolyte Aqueous phase Résumé : Polyelectrolyte multilayer (PEM) transfer printing has been previously achieved by stamping under dry conditions. Here, we show for the first time that PEM can be transferred from a stamp to the base substrate under aqueous conditions whereby the two surfaces are in a noncontact mode. Degradable multilayers of (PAA/PEG)10.5 followed by nondegradable multilayers of (PDAC/SPS)80.5 were fabricated under acidic pH conditions on either PDMS or glass (stamp), and subsequently transferred over top of another multilayer prepared on a different substrate (base substrate), with a spacing of 200 μm between the stamping surface and the base substrate. This multilayer transfer was performed under physiological pH conditions. This process is referred to herein as noncontact, aqueous-phase multilayer (NAM) transfer. NAM transfer can be useful for applications such as fabricating three-dimensional (3-D) cellular scaffolds. We attempted to create a 3-D cellular scaffold using NAM transfer, and characterized the scaffolds with conventional and fluorescence microscopy. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102011m

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Transient two-dimensional dehumidification and desorption behavior of plate desiccants under humid air flow / Hassan S. Al-Sharqawi in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8859-8880 Titre : Transient two-dimensional dehumidification and desorption behavior of plate desiccants under humid air flow : a conjugate model that includes diffusion and adsorption/desorption within the desiccant Type de document : texte imprimé Auteurs : Hassan S. Al-Sharqawi, Auteur Année de publication : 2011 Article en page(s) : pp. 8859-8880 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Adsorption Diffusion Modeling Air flow Desorption Dehumidification Résumé : A more rigorous conjugate-transient two-dimensional numerical model of solid bed desiccant systems (plates and narrow channels) used for gas dehumidification of a gas laminarly flowing along the desiccant, which, importantly, includes the associated transport through the desiccant body, was developed and validated. This improvement of the basic understanding of the process can be used for easier determination of ways for improving the overall performance of such systems. The solution provided a detailed exposition of the associated heat- and mass-transfer phenomena and of the desiccant performance, conducted here for both the adsorption and desorption processes in a range of air-flow Reynolds numbers and desiccant bed particle sizes and for two types of desiccant materials, silica gel and polystyrenesulfonic acid sodium salt (PSSASS) polymer. The results were also compared to those from an authors' simpler model that was published earlier and that does not consider transport through the solid desiccant. The new model was also employed to define and compute an "effective diffusion coefficient" from the basic composition of the desiccant, which is useful for characterizing desiccant properties and behavior in practical analysis. Besides the detailed behavior, some of the practical results are as follows: (i) the adsorption/desorption processes occur much faster at the flow entrance region; (ii) the mass-transport rates increase with the Reynolds number; (iii) within the studied range, manufacturing of the solid desiccant from larger particles raises its mass-transport rates; (iv) the water content and adsorption rate for PSSASS are larger than those for silica gel, thus making PSSASS a more effective desiccant than silica geL. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395832 [article] Transient two-dimensional dehumidification and desorption behavior of plate desiccants under humid air flow : a conjugate model that includes diffusion and adsorption/desorption within the desiccant [texte imprimé] / Hassan S. Al-Sharqawi, Auteur . - 2011 . - pp. 8859-8880. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8859-8880 Mots-clés : Adsorption Diffusion Modeling Air flow Desorption Dehumidification Résumé : A more rigorous conjugate-transient two-dimensional numerical model of solid bed desiccant systems (plates and narrow channels) used for gas dehumidification of a gas laminarly flowing along the desiccant, which, importantly, includes the associated transport through the desiccant body, was developed and validated. This improvement of the basic understanding of the process can be used for easier determination of ways for improving the overall performance of such systems. The solution provided a detailed exposition of the associated heat- and mass-transfer phenomena and of the desiccant performance, conducted here for both the adsorption and desorption processes in a range of air-flow Reynolds numbers and desiccant bed particle sizes and for two types of desiccant materials, silica gel and polystyrenesulfonic acid sodium salt (PSSASS) polymer. The results were also compared to those from an authors' simpler model that was published earlier and that does not consider transport through the solid desiccant. The new model was also employed to define and compute an "effective diffusion coefficient" from the basic composition of the desiccant, which is useful for characterizing desiccant properties and behavior in practical analysis. Besides the detailed behavior, some of the practical results are as follows: (i) the adsorption/desorption processes occur much faster at the flow entrance region; (ii) the mass-transport rates increase with the Reynolds number; (iii) within the studied range, manufacturing of the solid desiccant from larger particles raises its mass-transport rates; (iv) the water content and adsorption rate for PSSASS are larger than those for silica gel, thus making PSSASS a more effective desiccant than silica geL. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395832

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Prediction of the turbulent prandtl number in wall flows with lagrangian simulations / Chiranth Srinivasan in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8881-8891 Titre : Prediction of the turbulent prandtl number in wall flows with lagrangian simulations Type de document : texte imprimé Auteurs : Chiranth Srinivasan, Auteur ; Dimitrios V. Papavassiliou, Auteur Année de publication : 2011 Article en page(s) : pp. 8881-8891 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Prandtl number Prediction Résumé : The turbulent Prandtl number (Prt) is an important parameter in modeling turbulent transport, and a lot of effort has been placed in studying its behavior in wall turbulence. This work applied the Churchill model for turbulence scaling to determine the Prt. Two different computational approaches involving a direct numerical simulation in conjunction with Lagrangian techniques were utilized. In the first approach, the local fractions of shear stress and heat flux density, as defined using Churchill's scaling model and determined previously by Le and Papavassiliou [Le, P. M.; Papavassiliou, D. V. On temperature prediction at low Re turbulent flows using the Churchill turbulent heat flux correlation. Int. J. Heat Mass Transfer. 2006, 49, 3681-3690], were used to calculate the Prt. For Poiseuille channel flow, the Prt, at distances far away from the channel walls, was found to have a value between 0.8 and 0.9 irrespective of the molecular Prandtl number, while for plane Couette flow, it was found to be between 0.7 and 1.5. An alternative approach to determining the Pr, is to translate Churchill's physical interpretation of Pr, in a Lagrangian sense. Contributions of turbulent and molecular transport to momentum and heat transfer were calculated to find the local fractions of shear stress and heat flux density. For both Poiseuille channel and Couette flows, the Prt at Pr= 0.1 in regions near the center of the channel was higher than that at higher Pr. For Pr > 0.7, in the case of Poiseuille flow and plane Couette flow, the Prt started from values above 1 decreased and then followed a similar trend to that of the lower molecular Pr. The near-wall Prt increased with increasing Pr for both types of turbulent flow. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395833 [article] Prediction of the turbulent prandtl number in wall flows with lagrangian simulations [texte imprimé] / Chiranth Srinivasan, Auteur ; Dimitrios V. Papavassiliou, Auteur . - 2011 . - pp. 8881-8891. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8881-8891 Mots-clés : Prandtl number Prediction Résumé : The turbulent Prandtl number (Prt) is an important parameter in modeling turbulent transport, and a lot of effort has been placed in studying its behavior in wall turbulence. This work applied the Churchill model for turbulence scaling to determine the Prt. Two different computational approaches involving a direct numerical simulation in conjunction with Lagrangian techniques were utilized. In the first approach, the local fractions of shear stress and heat flux density, as defined using Churchill's scaling model and determined previously by Le and Papavassiliou [Le, P. M.; Papavassiliou, D. V. On temperature prediction at low Re turbulent flows using the Churchill turbulent heat flux correlation. Int. J. Heat Mass Transfer. 2006, 49, 3681-3690], were used to calculate the Prt. For Poiseuille channel flow, the Prt, at distances far away from the channel walls, was found to have a value between 0.8 and 0.9 irrespective of the molecular Prandtl number, while for plane Couette flow, it was found to be between 0.7 and 1.5. An alternative approach to determining the Pr, is to translate Churchill's physical interpretation of Pr, in a Lagrangian sense. Contributions of turbulent and molecular transport to momentum and heat transfer were calculated to find the local fractions of shear stress and heat flux density. For both Poiseuille channel and Couette flows, the Prt at Pr= 0.1 in regions near the center of the channel was higher than that at higher Pr. For Pr > 0.7, in the case of Poiseuille flow and plane Couette flow, the Prt started from values above 1 decreased and then followed a similar trend to that of the lower molecular Pr. The near-wall Prt increased with increasing Pr for both types of turbulent flow. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395833

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A robust homotopy continuation method for seeking all real roots of unconstrained systems of nonlinear algebraic and transcendental equations / Saeed Khaleghi Rahimian in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8892–8900 Titre : A robust homotopy continuation method for seeking all real roots of unconstrained systems of nonlinear algebraic and transcendental equations Type de document : texte imprimé Auteurs : Saeed Khaleghi Rahimian, Auteur ; Farhang Jalali, Auteur ; J. D. Seader, Auteur Année de publication : 2011 Article en page(s) : pp. 8892–8900 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Continuation method Homotopy Résumé : A new homotopy developed for finding all real roots to a single nonlinear equation is extended to a system of nonlinear algebraic and transcendental equations written as f{x} = 0 to find all real roots, including those on isolas. To reach roots that may lie on isolas, the functions are squared. This causes all roots to be bifurcation points that are connected to each other through stemming branches. As a result, a new system of homotopy functions, including numerous bifurcation points, is formed as H{x,t} = (x-x0) ( 1 + f2 - t), where x0 is the starting point. Because the functions are squared, many systems of equations must be solved to find a starting point on a reduced system of homotopy functions written as H{x,t} = 1 + f2 - t. Therefore, robustness is achieved at the expense of increased computation time. To improve the efficiency of the algorithm, the Levenberg-Marquardt method is used to find the starting point for the reduced homotopy system by solving a system of nonlinear equations with the degree of freedom equal to one. Then, a continuation method is used to track the paths from the resulting starting point to seek at least one root. Because all roots are bifurcation points, tracking the stemming branches from each subsequent root is the final step. The new algorithm was able to find successfully all the reported roots for 20 test problems that included a variety of algebraic and transcendental terms. In some cases additional roots were obtained. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395834 [article] A robust homotopy continuation method for seeking all real roots of unconstrained systems of nonlinear algebraic and transcendental equations [texte imprimé] / Saeed Khaleghi Rahimian, Auteur ; Farhang Jalali, Auteur ; J. D. Seader, Auteur . - 2011 . - pp. 8892–8900. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8892–8900 Mots-clés : Continuation method Homotopy Résumé : A new homotopy developed for finding all real roots to a single nonlinear equation is extended to a system of nonlinear algebraic and transcendental equations written as f{x} = 0 to find all real roots, including those on isolas. To reach roots that may lie on isolas, the functions are squared. This causes all roots to be bifurcation points that are connected to each other through stemming branches. As a result, a new system of homotopy functions, including numerous bifurcation points, is formed as H{x,t} = (x-x0) ( 1 + f2 - t), where x0 is the starting point. Because the functions are squared, many systems of equations must be solved to find a starting point on a reduced system of homotopy functions written as H{x,t} = 1 + f2 - t. Therefore, robustness is achieved at the expense of increased computation time. To improve the efficiency of the algorithm, the Levenberg-Marquardt method is used to find the starting point for the reduced homotopy system by solving a system of nonlinear equations with the degree of freedom equal to one. Then, a continuation method is used to track the paths from the resulting starting point to seek at least one root. Because all roots are bifurcation points, tracking the stemming branches from each subsequent root is the final step. The new algorithm was able to find successfully all the reported roots for 20 test problems that included a variety of algebraic and transcendental terms. In some cases additional roots were obtained. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395834

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A general process model of sustainability / Michael Neuman in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8901–8904 Titre : A general process model of sustainability Type de document : texte imprimé Auteurs : Michael Neuman, Auteur Année de publication : 2011 Article en page(s) : pp. 8901–8904 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Process model sustainability Résumé : Sustainability is high on many research and policy agendas, and a number of specific models to measure sustainability have been developed. However, most models are based only on the first law of thermodynamics and, thereby, are incomplete and approximate. Sustainable processes are those whose rates are maintained over time without exceeding the innate ability of their surroundings to support the process. We present a model for measuring the sustainability of processes that adapts and integrates the first and second laws of thermodynamics and the concept of rate processes, thereby forming a new synthesis. The degree of sustainability of a process, whether ecological, economic, social, chemical, or biological, is expressed quantitatively in terms of algebraic equations. It is a dynamic approach that applies at any scale and takes into consideration the spatial and temporal factors of processes, thus permitting empirical applications that correspond to real world conditions (dynamic, complex, and evolving). These characteristics make it especially suitable for applications in the fields of chemistry, chemical engineering, and ecology. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1020156 [article] A general process model of sustainability [texte imprimé] / Michael Neuman, Auteur . - 2011 . - pp. 8901–8904. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8901–8904 Mots-clés : Process model sustainability Résumé : Sustainability is high on many research and policy agendas, and a number of specific models to measure sustainability have been developed. However, most models are based only on the first law of thermodynamics and, thereby, are incomplete and approximate. Sustainable processes are those whose rates are maintained over time without exceeding the innate ability of their surroundings to support the process. We present a model for measuring the sustainability of processes that adapts and integrates the first and second laws of thermodynamics and the concept of rate processes, thereby forming a new synthesis. The degree of sustainability of a process, whether ecological, economic, social, chemical, or biological, is expressed quantitatively in terms of algebraic equations. It is a dynamic approach that applies at any scale and takes into consideration the spatial and temporal factors of processes, thus permitting empirical applications that correspond to real world conditions (dynamic, complex, and evolving). These characteristics make it especially suitable for applications in the fields of chemistry, chemical engineering, and ecology. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1020156

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Turbulent energy redistribution in spanwise rotating channel flows / Karuna S. Koppula in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8905–8916 Titre : Turbulent energy redistribution in spanwise rotating channel flows Type de document : texte imprimé Auteurs : Karuna S. Koppula, Auteur ; Andre Benard, Auteur ; Charles A. Petty, Auteur Année de publication : 2011 Article en page(s) : pp. 8905–8916 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Pipe flow Channel Résumé : For fully developed turbulent flows of a Newtonian fluid in a nonrotating channel with a large aspect ratio (i.e., spanwise length scale transverse length scale), the longitudinal component of the mean velocity and the mean pressure are symmetrical functions of the transverse coordinate. The three unequal normal components of the Reynolds stress are also symmetrical functions about the midplane whereas the shear component of the Reynolds stress is spatially antisymmetric. However, if the channel rotates around the spanwise axis, the Coriolis acceleration breaks the spatial symmetry of the flow field. This phenomenon occurs because the angular velocity of the frame directly couples with the linear momentum of the flow field to redistribute the turbulent kinetic energy. Consequently, rotating channel flows are ideal for testing the efficacy of closure models for the Reynolds averaged Navier−Stokes (RANS) equation. It is noteworthy that none of the classical “eddy” viscosity models are able to predict the Coriolis symmetry breaking phenomenon in spanwise rotating fully developed channel flows. This fundamental deficiency occurs because the “eddy” viscosity hypothesis assumes that the Reynolds stress is a frame-indifferent dyadic-valued operator (i.e., objective). Unlike the viscous transport of momentum, the transport of momentum by turbulent fluctuations is directly influenced by the angular velocity of the reference frame. In this paper, a recently developed algebraic closure for the Reynolds stress [see Koppula, K.; Benard, A.; Petty, C. Realizable Algebraic Reynolds Stress Closure. Chem. Eng. Sci.2009, 64, 4611], referred to hereinafter as the universal realizable anisotropic prestress (URAPS) closure, is used to predict the spatial distribution of the normalized Reynolds (NR) stress (i.e., ≡ /tr() for rotating and for nonrotating fully developed channel flows. The new closure is formulated as an algebraic mapping of the NR stress into itself and is, thereby, realizable for all turbulent flows regardless of the specific benchmark flows used to estimate model parameters. The fixed points of the non-negative mapping depend explicitly on three specific time scales associated with the local statistical state of turbulence. The a priori predictions of the NR stress are consistent with previously published direct numerical simulations of the Navier−Stokes equation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395836 [article] Turbulent energy redistribution in spanwise rotating channel flows [texte imprimé] / Karuna S. Koppula, Auteur ; Andre Benard, Auteur ; Charles A. Petty, Auteur . - 2011 . - pp. 8905–8916. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8905–8916 Mots-clés : Pipe flow Channel Résumé : For fully developed turbulent flows of a Newtonian fluid in a nonrotating channel with a large aspect ratio (i.e., spanwise length scale transverse length scale), the longitudinal component of the mean velocity and the mean pressure are symmetrical functions of the transverse coordinate. The three unequal normal components of the Reynolds stress are also symmetrical functions about the midplane whereas the shear component of the Reynolds stress is spatially antisymmetric. However, if the channel rotates around the spanwise axis, the Coriolis acceleration breaks the spatial symmetry of the flow field. This phenomenon occurs because the angular velocity of the frame directly couples with the linear momentum of the flow field to redistribute the turbulent kinetic energy. Consequently, rotating channel flows are ideal for testing the efficacy of closure models for the Reynolds averaged Navier−Stokes (RANS) equation. It is noteworthy that none of the classical “eddy” viscosity models are able to predict the Coriolis symmetry breaking phenomenon in spanwise rotating fully developed channel flows. This fundamental deficiency occurs because the “eddy” viscosity hypothesis assumes that the Reynolds stress is a frame-indifferent dyadic-valued operator (i.e., objective). Unlike the viscous transport of momentum, the transport of momentum by turbulent fluctuations is directly influenced by the angular velocity of the reference frame. In this paper, a recently developed algebraic closure for the Reynolds stress [see Koppula, K.; Benard, A.; Petty, C. Realizable Algebraic Reynolds Stress Closure. Chem. Eng. Sci.2009, 64, 4611], referred to hereinafter as the universal realizable anisotropic prestress (URAPS) closure, is used to predict the spatial distribution of the normalized Reynolds (NR) stress (i.e., ≡ /tr() for rotating and for nonrotating fully developed channel flows. The new closure is formulated as an algebraic mapping of the NR stress into itself and is, thereby, realizable for all turbulent flows regardless of the specific benchmark flows used to estimate model parameters. The fixed points of the non-negative mapping depend explicitly on three specific time scales associated with the local statistical state of turbulence. The a priori predictions of the NR stress are consistent with previously published direct numerical simulations of the Navier−Stokes equation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395836

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The constrained vapor bubble fin heat pipe in microgravity / Arya Chatterjee in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8917-8926 Titre : The constrained vapor bubble fin heat pipe in microgravity Type de document : texte imprimé Auteurs : Arya Chatterjee, Auteur ; Peter C. Wayner, Auteur ; Joel L. Plawsky, Auteur Année de publication : 2011 Article en page(s) : pp. 8917-8926 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Microgravity Fin Bubble Résumé : The Constrained Vapor Bubble (CVB) is a wickless, grooved heat pipe and is the first, full-scale fluids experiment flown on the U.S. module of the International Space Station. The CVB promises to provide new insight into the operation of a heat pipe in space. It is a relatively simple device constructed from a spectrophotometer cuvette and uses pentane as the working fluid. The pentane flows within the comers of the cuvette due to a curvature gradient in the liquid menisci associated with the cuvette comers. The curvature of the liquid interface can be determined by viewing the meniscus through the transparent quartz walls. Extremely accurate temperature and pressure measurements were obtained in addition to the images. In the article, the results from the first two CVB modules-a dry calibration module and a wet heat pipe module-are presented. We show that the axial temperature profiles are significantly different in space. The heat pipes were seen to operate at a higher pressure and higher temperature in space primarily because radiation was the only heat loss mechanism. A fin model was developed to model the data, and Churchill's correlations for natural convection were used to determine the external heat transfer coefficient. Inside evaporation and condensation heat transfer coefficients were regressed from the temperature data. We show that the heat transfer coefficient in microgravity was higher. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395837 [article] The constrained vapor bubble fin heat pipe in microgravity [texte imprimé] / Arya Chatterjee, Auteur ; Peter C. Wayner, Auteur ; Joel L. Plawsky, Auteur . - 2011 . - pp. 8917-8926. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8917-8926 Mots-clés : Microgravity Fin Bubble Résumé : The Constrained Vapor Bubble (CVB) is a wickless, grooved heat pipe and is the first, full-scale fluids experiment flown on the U.S. module of the International Space Station. The CVB promises to provide new insight into the operation of a heat pipe in space. It is a relatively simple device constructed from a spectrophotometer cuvette and uses pentane as the working fluid. The pentane flows within the comers of the cuvette due to a curvature gradient in the liquid menisci associated with the cuvette comers. The curvature of the liquid interface can be determined by viewing the meniscus through the transparent quartz walls. Extremely accurate temperature and pressure measurements were obtained in addition to the images. In the article, the results from the first two CVB modules-a dry calibration module and a wet heat pipe module-are presented. We show that the axial temperature profiles are significantly different in space. The heat pipes were seen to operate at a higher pressure and higher temperature in space primarily because radiation was the only heat loss mechanism. A fin model was developed to model the data, and Churchill's correlations for natural convection were used to determine the external heat transfer coefficient. Inside evaporation and condensation heat transfer coefficients were regressed from the temperature data. We show that the heat transfer coefficient in microgravity was higher. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395837

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Reality of diffuse volume flow in fluid continua / Howard Brenner in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8927–8931 Titre : Reality of diffuse volume flow in fluid continua Type de document : texte imprimé Auteurs : Howard Brenner, Auteur Année de publication : 2011 Article en page(s) : pp. 8927–8931 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Volume flow Fluid continua Résumé : A gedankenexperiment is outlined that confirms the reality of diffuse volume transport in fluid continua. This example shows, inter alia, that the phenomenon is not limited to rarefied gases but is, in fact, a strictly continuum phenomenon, valid for both gases and liquids. Moreover, it is shown that volume-regarded as an extensive thermodynamic property of matter-can flow unaccompanied by matter through solid surfaces, in much the same manner as can internal energy ("heat"). DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102106j [article] Reality of diffuse volume flow in fluid continua [texte imprimé] / Howard Brenner, Auteur . - 2011 . - pp. 8927–8931. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8927–8931 Mots-clés : Volume flow Fluid continua Résumé : A gedankenexperiment is outlined that confirms the reality of diffuse volume transport in fluid continua. This example shows, inter alia, that the phenomenon is not limited to rarefied gases but is, in fact, a strictly continuum phenomenon, valid for both gases and liquids. Moreover, it is shown that volume-regarded as an extensive thermodynamic property of matter-can flow unaccompanied by matter through solid surfaces, in much the same manner as can internal energy ("heat"). DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102106j

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Novel features of aerosol coagulation in nonisothermal environments / Daniel E. Rosner in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8932–8940 Titre : Novel features of aerosol coagulation in nonisothermal environments Type de document : texte imprimé Auteurs : Daniel E. Rosner, Auteur ; Manuel Arias-Zugasti, Auteur Année de publication : 2011 Article en page(s) : pp. 8932–8940 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Aerosol coagulation Résumé : Local supersaturations and the rapid homogeneous nucleation of often subcooled nanometric particles occur when vapors from a high-temperature source diffuse into adjacent regions of much lower temperature. While earlier experimental and theoretical studies were focused on the macroscopic mass transfer rate consequences of such localized condensation (Turkdogan and Mills (1964), Epstein and Rosner (1970)), we identify and describe here, from a broader perspective, several expected novel features of aerosol coagulation dynamics in nonisothermal environments, including the expected particle size “spectra”. In the simplest (limiting) case, differential thermal particle drift down the local temperature gradient dominates the Brownian diffusion-controlled collision rate, and, for a population of thermally conductive mist droplets coagulating by this mechanism, we have calculated and displayed (e.g., Rosner, D. E.; Arias-Zugasti, M. Thermophoretically-dominated aerosol coagulation. Phys. Rev. Lett.2011, 106, 015502.) the expected coagulation-aged “self-preserving” droplet size distribution. However, in most applications the more familiar Brownian diffusion contribution to the coagulation rate must also be included, and we summarize here our recent analysis of this combined case, which enables another test of the frequently made assumption of “additive rate constants” and leads to quasi-self-preserving droplet size distributions. Because fully miscible mist droplets may also be distributed with respect to composition (and, hence, thermal conductivity) we take this opportunity to outline how these, and more general phoretic mechanisms (including thermocapillary flow), can be incorporated into the present formulation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102444e [article] Novel features of aerosol coagulation in nonisothermal environments [texte imprimé] / Daniel E. Rosner, Auteur ; Manuel Arias-Zugasti, Auteur . - 2011 . - pp. 8932–8940. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8932–8940 Mots-clés : Aerosol coagulation Résumé : Local supersaturations and the rapid homogeneous nucleation of often subcooled nanometric particles occur when vapors from a high-temperature source diffuse into adjacent regions of much lower temperature. While earlier experimental and theoretical studies were focused on the macroscopic mass transfer rate consequences of such localized condensation (Turkdogan and Mills (1964), Epstein and Rosner (1970)), we identify and describe here, from a broader perspective, several expected novel features of aerosol coagulation dynamics in nonisothermal environments, including the expected particle size “spectra”. In the simplest (limiting) case, differential thermal particle drift down the local temperature gradient dominates the Brownian diffusion-controlled collision rate, and, for a population of thermally conductive mist droplets coagulating by this mechanism, we have calculated and displayed (e.g., Rosner, D. E.; Arias-Zugasti, M. Thermophoretically-dominated aerosol coagulation. Phys. Rev. Lett.2011, 106, 015502.) the expected coagulation-aged “self-preserving” droplet size distribution. However, in most applications the more familiar Brownian diffusion contribution to the coagulation rate must also be included, and we summarize here our recent analysis of this combined case, which enables another test of the frequently made assumption of “additive rate constants” and leads to quasi-self-preserving droplet size distributions. Because fully miscible mist droplets may also be distributed with respect to composition (and, hence, thermal conductivity) we take this opportunity to outline how these, and more general phoretic mechanisms (including thermocapillary flow), can be incorporated into the present formulation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102444e

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Supercritical carbon dioxide extraction of molecules of interest from microalgae and seaweeds / Christelle Crampon in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8941–8953 Titre : Supercritical carbon dioxide extraction of molecules of interest from microalgae and seaweeds Type de document : texte imprimé Auteurs : Christelle Crampon, Auteur ; Olivier Boutin, Auteur ; Elisabeth Badens, Auteur Année de publication : 2011 Article en page(s) : pp. 8941–8953 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Algae Supercritical fluid extraction Résumé : The purpose of this paper is to guide lectors in the extraction of algal (microalgae and seaweeds) compounds using supercritical carbon dioxide (SC-CO2) from dry biomass. It proposes a review of 30 articles dealing with the SC-CO2 extraction of molecules of interest from microalgae and seaweeds. Among these papers, 20 are devoted to microalgae. The most extracted compounds are neutral lipids and antioxidants. Several operating conditions have been tested: pressures from 7.8 to 70 MPa, temperatures from 313.15 to 349.15 K, and CO2/algae mass ratio from 6 to 500. All extraction studies were performed at laboratory scale, with the masses of dry algae powder never exceeding 180 g. Extraction yields vary significantly with operating conditions: pressure seems to be the most influential parameter. The higher the pressure, the higher the yields and/or the faster the extraction kinetics. Temperature also has an influence, but its effect is dependent on pressure (retrograde behavior). Moreover, as expected, it is advised to work with a high CO2/algae mass ratio. From these works, it appears that, to perform an efficient extraction with SC–CO2, the influence of the algae pretreatment is highly significant. The first step is a centrifugation. The resulting concentrated algal suspension must then undergo a drying operation, which is generally freeze-drying or low-temperature drying. Finally, the algae are crushed. Concerning the influence of crushing, the reported results show that, as expected, the smaller the particles, the more rapid the extraction kinetics and/or the higher the yields. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395840 [article] Supercritical carbon dioxide extraction of molecules of interest from microalgae and seaweeds [texte imprimé] / Christelle Crampon, Auteur ; Olivier Boutin, Auteur ; Elisabeth Badens, Auteur . - 2011 . - pp. 8941–8953. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8941–8953 Mots-clés : Algae Supercritical fluid extraction Résumé : The purpose of this paper is to guide lectors in the extraction of algal (microalgae and seaweeds) compounds using supercritical carbon dioxide (SC-CO2) from dry biomass. It proposes a review of 30 articles dealing with the SC-CO2 extraction of molecules of interest from microalgae and seaweeds. Among these papers, 20 are devoted to microalgae. The most extracted compounds are neutral lipids and antioxidants. Several operating conditions have been tested: pressures from 7.8 to 70 MPa, temperatures from 313.15 to 349.15 K, and CO2/algae mass ratio from 6 to 500. All extraction studies were performed at laboratory scale, with the masses of dry algae powder never exceeding 180 g. Extraction yields vary significantly with operating conditions: pressure seems to be the most influential parameter. The higher the pressure, the higher the yields and/or the faster the extraction kinetics. Temperature also has an influence, but its effect is dependent on pressure (retrograde behavior). Moreover, as expected, it is advised to work with a high CO2/algae mass ratio. From these works, it appears that, to perform an efficient extraction with SC–CO2, the influence of the algae pretreatment is highly significant. The first step is a centrifugation. The resulting concentrated algal suspension must then undergo a drying operation, which is generally freeze-drying or low-temperature drying. Finally, the algae are crushed. Concerning the influence of crushing, the reported results show that, as expected, the smaller the particles, the more rapid the extraction kinetics and/or the higher the yields. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395840

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Solar energy storage methods / Yu Hou in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8954–8964 Titre : Solar energy storage methods Type de document : texte imprimé Auteurs : Yu Hou, Auteur ; Ruxandra Vidu, Auteur ; Pieter Stroeve, Auteur Année de publication : 2011 Article en page(s) : pp. 8954–8964 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Solar energy Résumé : Solar energy can provide an abundant source of renewable energy (electrical and thermal). However, because of its unsteady nature, the storage of solar energy will become critical when a significant portion of the total energy will be provided by solar energy. In this paper, current solar energy storage technologies are reviewed. Storage methods can be classified into categories according to capacity and discharge time. New developments in solar energy storage require advances in chemical engineering and materials science. Life cycle assessment (LCA) is an important tool to evaluate energy consumption and environmental impact of renewable energy processes. LCAs of some of the storage methods are reviewed. It is important to note that, while using renewable energy sources such as solar power, storage methods based on nonrecyclable materials or methods that consume significant amounts of energy may undermine the effort to reduce energy consumption. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2003413 [article] Solar energy storage methods [texte imprimé] / Yu Hou, Auteur ; Ruxandra Vidu, Auteur ; Pieter Stroeve, Auteur . - 2011 . - pp. 8954–8964. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8954–8964 Mots-clés : Solar energy Résumé : Solar energy can provide an abundant source of renewable energy (electrical and thermal). However, because of its unsteady nature, the storage of solar energy will become critical when a significant portion of the total energy will be provided by solar energy. In this paper, current solar energy storage technologies are reviewed. Storage methods can be classified into categories according to capacity and discharge time. New developments in solar energy storage require advances in chemical engineering and materials science. Life cycle assessment (LCA) is an important tool to evaluate energy consumption and environmental impact of renewable energy processes. LCAs of some of the storage methods are reviewed. It is important to note that, while using renewable energy sources such as solar power, storage methods based on nonrecyclable materials or methods that consume significant amounts of energy may undermine the effort to reduce energy consumption. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2003413

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Empirical models for the decoloration of dyes in an electrochemical batch cell / Montserrat Pepio in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8965–8972 Titre : Empirical models for the decoloration of dyes in an electrochemical batch cell Type de document : texte imprimé Auteurs : Montserrat Pepio, Auteur ; M. Carmen Gutierrez-Bouzan, Auteur Année de publication : 2011 Article en page(s) : pp. 8965–8972 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Batchwise Dyes Discoloration Empirical model Résumé : Among several types of textiles colorants, reactive dyes represent about 30-50% of the total market share, and the most common group used as chromophore is the azo group (70%), followed by anthraquinone. The removal of such dyes from wastewater is a problem in textile mills. Electrochemical treatment has proven to be an interesting technique for removing dyes from wastewater, as it does not require any added chemical reagents. Generally, this technique is applied to obtain partial dye degradation (until color removal). In this work, electrochemical treatment was performed in a batch cell. The influence of conductivity, temperature, pH, dye concentration, and dyeing electrolyte on the decoloration was studied. The time required to reach a fixed level of decoloration and the corresponding electricity consumption were also evaluated. Six reactive dyes with different chromophores and reactive goups were selected. The main statistical study was carried out on CI Reactive Orange 13, a textile dye with the commercial name Procion Orange PX-2R (OrPX). Subsequently, the behavior of the other dyes was studied in comparison with the OrPX models. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395842 [article] Empirical models for the decoloration of dyes in an electrochemical batch cell [texte imprimé] / Montserrat Pepio, Auteur ; M. Carmen Gutierrez-Bouzan, Auteur . - 2011 . - pp. 8965–8972. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8965–8972 Mots-clés : Batchwise Dyes Discoloration Empirical model Résumé : Among several types of textiles colorants, reactive dyes represent about 30-50% of the total market share, and the most common group used as chromophore is the azo group (70%), followed by anthraquinone. The removal of such dyes from wastewater is a problem in textile mills. Electrochemical treatment has proven to be an interesting technique for removing dyes from wastewater, as it does not require any added chemical reagents. Generally, this technique is applied to obtain partial dye degradation (until color removal). In this work, electrochemical treatment was performed in a batch cell. The influence of conductivity, temperature, pH, dye concentration, and dyeing electrolyte on the decoloration was studied. The time required to reach a fixed level of decoloration and the corresponding electricity consumption were also evaluated. Six reactive dyes with different chromophores and reactive goups were selected. The main statistical study was carried out on CI Reactive Orange 13, a textile dye with the commercial name Procion Orange PX-2R (OrPX). Subsequently, the behavior of the other dyes was studied in comparison with the OrPX models. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395842

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La Complex@Fe–pILM offering resilient option for efficient and green processing toward epoxidation of cyclohexene / Guru Bishwa Bidita Varadwaj in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8973–8982 Titre : La Complex@Fe–pILM offering resilient option for efficient and green processing toward epoxidation of cyclohexene Type de document : texte imprimé Auteurs : Guru Bishwa Bidita Varadwaj, Auteur ; Swagatika Sahu, Auteur ; Kulamani Parida, Auteur Année de publication : 2011 Article en page(s) : pp. 8973–8982 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Epoxidation Résumé : An overview focused on the synthesis, structural features, and catalytic applications of lanthanum salen complex heterogenized in iron pillared montmorillonite is described here. In this approach the pillaring species was introduced in the interlayers of montmorillonite by a simple cation-exchange mechanism. The material on subsequent calcination resulted in the formation of iron pillared montmorillonite. Consequently, lanthanum salen complex was intercalated into the porous structure of iron pillared montmorillonite. The prima facie evidence of pillaring and complex anchorage inside the pillared clay was established by various spectroscopic and analytical characterization techniques. The heterogeneous catalyst was identified to promote the cyclohexene epoxidation reaction very efficiently with tert-butylhydroperoxide (TBHP) as the oxidant, affording the desired product with a yield up to 95%. Again the reusability of the catalyst and its stability were investigated from its postcatalytic XRD and FT-IR analysis, which intimated that the catalyst could be reused up to four times without any reconditioning and loss of activity. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395843 [article] La Complex@Fe–pILM offering resilient option for efficient and green processing toward epoxidation of cyclohexene [texte imprimé] / Guru Bishwa Bidita Varadwaj, Auteur ; Swagatika Sahu, Auteur ; Kulamani Parida, Auteur . - 2011 . - pp. 8973–8982. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8973–8982 Mots-clés : Epoxidation Résumé : An overview focused on the synthesis, structural features, and catalytic applications of lanthanum salen complex heterogenized in iron pillared montmorillonite is described here. In this approach the pillaring species was introduced in the interlayers of montmorillonite by a simple cation-exchange mechanism. The material on subsequent calcination resulted in the formation of iron pillared montmorillonite. Consequently, lanthanum salen complex was intercalated into the porous structure of iron pillared montmorillonite. The prima facie evidence of pillaring and complex anchorage inside the pillared clay was established by various spectroscopic and analytical characterization techniques. The heterogeneous catalyst was identified to promote the cyclohexene epoxidation reaction very efficiently with tert-butylhydroperoxide (TBHP) as the oxidant, affording the desired product with a yield up to 95%. Again the reusability of the catalyst and its stability were investigated from its postcatalytic XRD and FT-IR analysis, which intimated that the catalyst could be reused up to four times without any reconditioning and loss of activity. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395843

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

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

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Analytical pyrolysis As a method to characterize tannery wastes / Antonio Marcilla in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8994–9002 Titre : Analytical pyrolysis As a method to characterize tannery wastes Type de document : texte imprimé Auteurs : Antonio Marcilla, Auteur ; Angela Nuria Garcia, Auteur ; Milagros Leon, Auteur Année de publication : 2011 Article en page(s) : pp. 8994–9002 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Leather industry Tannery Pyrolysis Résumé : The main objective of this paper is to study the thermal decomposition of waste products from leathers tanned with different tanning agents, from two different points of view: (i) thermogavimetric analysis and (ii) flash pyrolysis using a Pyroprobe device connected to a gas chromatograph with a mass spectrometer (Py/GC-MS). Both techniques allow us to characterize the samples by evaluating their potential differences regarding the decomposition process as well as by identifying the significant volatile compounds obtained depending on the tanning processes. The results have been treated using a multrvariate statistical analysis method. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395845 [article] Analytical pyrolysis As a method to characterize tannery wastes [texte imprimé] / Antonio Marcilla, Auteur ; Angela Nuria Garcia, Auteur ; Milagros Leon, Auteur . - 2011 . - pp. 8994–9002. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8994–9002 Mots-clés : Leather industry Tannery Pyrolysis Résumé : The main objective of this paper is to study the thermal decomposition of waste products from leathers tanned with different tanning agents, from two different points of view: (i) thermogavimetric analysis and (ii) flash pyrolysis using a Pyroprobe device connected to a gas chromatograph with a mass spectrometer (Py/GC-MS). Both techniques allow us to characterize the samples by evaluating their potential differences regarding the decomposition process as well as by identifying the significant volatile compounds obtained depending on the tanning processes. The results have been treated using a multrvariate statistical analysis method. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395845

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Efficient light scattering from one-pot solvothermally derived TiO2 nanospindles / Jun Jiang in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9003–9008 Titre : Efficient light scattering from one-pot solvothermally derived TiO2 nanospindles Type de document : texte imprimé Auteurs : Jun Jiang, Auteur ; Feng Gu, Auteur ; Xiang Ren, Auteur Année de publication : 2011 Article en page(s) : pp. 9003–9008 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Titanium oxide Light scattering Résumé : one-pot solvothermal approach has been developed for the synthesis of single-crystal anatase TiO2 nanospindles. The introduction of adscititious water in nonaqueous reaction mixture is critical for the spindle formation by allowing for a slow growth rate of TiO2 to facilitate the shape control of TiO2 nanospindles. Arising from the prominent light scattering effect, the fabricated dye sensitized solar cells with the TiO2 nanospindles as light scattering layer show a 27% increment of energy conversion efficiency compared to that of P25 single layer film. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395846 [article] Efficient light scattering from one-pot solvothermally derived TiO2 nanospindles [texte imprimé] / Jun Jiang, Auteur ; Feng Gu, Auteur ; Xiang Ren, Auteur . - 2011 . - pp. 9003–9008. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9003–9008 Mots-clés : Titanium oxide Light scattering Résumé : one-pot solvothermal approach has been developed for the synthesis of single-crystal anatase TiO2 nanospindles. The introduction of adscititious water in nonaqueous reaction mixture is critical for the spindle formation by allowing for a slow growth rate of TiO2 to facilitate the shape control of TiO2 nanospindles. Arising from the prominent light scattering effect, the fabricated dye sensitized solar cells with the TiO2 nanospindles as light scattering layer show a 27% increment of energy conversion efficiency compared to that of P25 single layer film. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395846

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Study on formation mechanism by monitoring the morphology and structure evolution of nearly monodispersed Fe3O4 submicroparticles with controlled particle sizes / Ting Fan in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9009–9018 Titre : Study on formation mechanism by monitoring the morphology and structure evolution of nearly monodispersed Fe3O4 submicroparticles with controlled particle sizes Type de document : texte imprimé Auteurs : Ting Fan, Auteur ; Dengke Pan, Auteur ; Hui Zhang, Auteur Année de publication : 2011 Article en page(s) : pp. 9009–9018 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Particle size Morphology Surveillance Formation mechanism Résumé : We present a facile surfactant-free solvothermal method for the fabrication of nearly monodispersed Fe3O4 submicroparticles with tunable particle sizes ranging from 130 to 420 nm by varying the concentration of single iron source FeCl3·6H2O in initial solutions. The morphology and crystal structure of the as-prepared Fe3O4 submicroparticles have been well characterized by using SEM/TEM/HRTEM, XRD, FT-IR, Raman spectroscopy, and XPS methods. It is found that the Fe3O4 particles present single-crystal nature and strong ferromagnetic property with magnetization saturation values ranged in 54.3–88.7 emu·g–1. A complexation–aggregation–phase transformation formation mechanism was first proposed for the nearly monodispersed single-crystal Fe3O4 submicroparticles based upon the quasi-in situ monitoring of the morphology and structure evolution of the samples during the synthesis process. These size-tunable nearly monodispersed Fe3O4 submicroparticles are expected to have promising applications in wide research fields such as bioseparation, targeted drug delivery, and catalysis. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395847 [article] Study on formation mechanism by monitoring the morphology and structure evolution of nearly monodispersed Fe3O4 submicroparticles with controlled particle sizes [texte imprimé] / Ting Fan, Auteur ; Dengke Pan, Auteur ; Hui Zhang, Auteur . - 2011 . - pp. 9009–9018. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9009–9018 Mots-clés : Particle size Morphology Surveillance Formation mechanism Résumé : We present a facile surfactant-free solvothermal method for the fabrication of nearly monodispersed Fe3O4 submicroparticles with tunable particle sizes ranging from 130 to 420 nm by varying the concentration of single iron source FeCl3·6H2O in initial solutions. The morphology and crystal structure of the as-prepared Fe3O4 submicroparticles have been well characterized by using SEM/TEM/HRTEM, XRD, FT-IR, Raman spectroscopy, and XPS methods. It is found that the Fe3O4 particles present single-crystal nature and strong ferromagnetic property with magnetization saturation values ranged in 54.3–88.7 emu·g–1. A complexation–aggregation–phase transformation formation mechanism was first proposed for the nearly monodispersed single-crystal Fe3O4 submicroparticles based upon the quasi-in situ monitoring of the morphology and structure evolution of the samples during the synthesis process. These size-tunable nearly monodispersed Fe3O4 submicroparticles are expected to have promising applications in wide research fields such as bioseparation, targeted drug delivery, and catalysis. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395847

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Vapor-phase propylene epoxidation with H2/O2 over bioreduction Au/TS-1 catalysts / Guowu Zhan in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - 9019-9026 Titre : Vapor-phase propylene epoxidation with H2/O2 over bioreduction Au/TS-1 catalysts : synthesis, characterization, and optimization Type de document : texte imprimé Auteurs : Guowu Zhan, Auteur ; Mingming Du, Auteur ; Daohua Sun, Auteur Année de publication : 2011 Article en page(s) : 9019-9026 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Optimization Catalyst Bioremediation Epoxidation Résumé : Au/TS-1 catalysts could be prepared by immobilizing the biosynthesized Au sol on TS-1 supports. A variety of techniques, such as N2 physisorption, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectorscopy, UV-visible diffuse reflectance, and thermogravimetric analysis, were employed to characterize both the supports and the bioreduction catalysts. The influence of various parameters (Si/Ti molar ratio, Au loading, immobilization pH, reaction temperature, and space velocity) on the catalytic performance in vapor phase propylene epoxidation with H2/O2 was systematically analyzed. parameter optimization results manifested that the optimum catalytic activity and stability of bioreduction Au/TS-1 catalysts were obtained of 573 optimum operation conditions of Si/Ti molar ratio Furthermore, of were also made to pH of 2, reaction temperature of 573 K, and space velocity of 4000-8000 mL gcat-1 h-1. Furthermore, efforts were also made to clarify the plausible reaction routes over the bioreduction catalysts. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395848 [article] Vapor-phase propylene epoxidation with H2/O2 over bioreduction Au/TS-1 catalysts : synthesis, characterization, and optimization [texte imprimé] / Guowu Zhan, Auteur ; Mingming Du, Auteur ; Daohua Sun, Auteur . - 2011 . - 9019-9026. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - 9019-9026 Mots-clés : Optimization Catalyst Bioremediation Epoxidation Résumé : Au/TS-1 catalysts could be prepared by immobilizing the biosynthesized Au sol on TS-1 supports. A variety of techniques, such as N2 physisorption, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectorscopy, UV-visible diffuse reflectance, and thermogravimetric analysis, were employed to characterize both the supports and the bioreduction catalysts. The influence of various parameters (Si/Ti molar ratio, Au loading, immobilization pH, reaction temperature, and space velocity) on the catalytic performance in vapor phase propylene epoxidation with H2/O2 was systematically analyzed. parameter optimization results manifested that the optimum catalytic activity and stability of bioreduction Au/TS-1 catalysts were obtained of 573 optimum operation conditions of Si/Ti molar ratio Furthermore, of were also made to pH of 2, reaction temperature of 573 K, and space velocity of 4000-8000 mL gcat-1 h-1. Furthermore, efforts were also made to clarify the plausible reaction routes over the bioreduction catalysts. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395848

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Surface optimization and redox behavior of vanadium oxides supported on γ-Al2O3 / Arindom Saha in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9027-9033 Titre : Surface optimization and redox behavior of vanadium oxides supported on γ-Al2O3 Type de document : texte imprimé Auteurs : Arindom Saha, Auteur ; Darrell P. Eyman, Auteur Année de publication : 2011 Article en page(s) : pp. 9027-9033 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Optimization Résumé : This report describes optimization of the synthesis of γ-Al2O3 supported vanadium oxides using three different vanadium precursors: OV(O'Pr)3, OV(OEt)3 and OV(OPr)3. It was observed that the actual loading of the metal oxide is controlled by a number of factors, including the kinetics and thermodynamics of the grafting process, the time allowed for the grafting reaction to proceed, the amount of available precursor, the concentration of the grafting solution, and temperature at which grafting is pursued. From TPR (temperature programmed reduction) and XPS (X-ray photoelectron spectroscopy) studies it was observed that V4+ and V5+ were the predominant oxidation states present under both normal and rigorous reducing conditions simulating those prevalent in the steam reforming process. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395849 [article] Surface optimization and redox behavior of vanadium oxides supported on γ-Al2O3 [texte imprimé] / Arindom Saha, Auteur ; Darrell P. Eyman, Auteur . - 2011 . - pp. 9027-9033. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9027-9033 Mots-clés : Optimization Résumé : This report describes optimization of the synthesis of γ-Al2O3 supported vanadium oxides using three different vanadium precursors: OV(O'Pr)3, OV(OEt)3 and OV(OPr)3. It was observed that the actual loading of the metal oxide is controlled by a number of factors, including the kinetics and thermodynamics of the grafting process, the time allowed for the grafting reaction to proceed, the amount of available precursor, the concentration of the grafting solution, and temperature at which grafting is pursued. From TPR (temperature programmed reduction) and XPS (X-ray photoelectron spectroscopy) studies it was observed that V4+ and V5+ were the predominant oxidation states present under both normal and rigorous reducing conditions simulating those prevalent in the steam reforming process. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395849

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Formation of carbon nanofibers from supported Pt catalysts through catalytic chemical vapor deposition from acetylene / Qilong Chen in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9034–9042 Titre : Formation of carbon nanofibers from supported Pt catalysts through catalytic chemical vapor deposition from acetylene Type de document : texte imprimé Auteurs : Qilong Chen, Auteur ; Jia Wang, Auteur ; Feng Li, Auteur Année de publication : 2011 Article en page(s) : pp. 9034–9042 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Chemical vapor deposition Catalytic reaction Catalyst Résumé : Carbon nanofibers (CNFs) were synthesized by catalytic chemical vapor deposition from acetylene from a series of supported Pt catalysts derived from Pt-containing Mg–Al layered double hydroxide precursors. The materials were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, temperature programmed reduction, low-temperature N2 adsorption–desorption experiments, X-ray photoelectron spectroscopy, and Raman spectroscopy. The effects of reaction temperature and Pt content on the morphologies and microstructures of CNFs were investigated. The results revealed that the reaction temperature of 600 °C was appropriate for the growth of uniform CNFs with regular shape. Furthermore, the structural defects and the diameters of CNFs were reduced with the increasing Pt content, which is attributable to the high dispersion of smaller Pt nanoparticles as well as the quick deposition rate of carbon atoms on active metal particles. The present work developed an additional approach to optimize the growth of CNFs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395850 [article] Formation of carbon nanofibers from supported Pt catalysts through catalytic chemical vapor deposition from acetylene [texte imprimé] / Qilong Chen, Auteur ; Jia Wang, Auteur ; Feng Li, Auteur . - 2011 . - pp. 9034–9042. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9034–9042 Mots-clés : Chemical vapor deposition Catalytic reaction Catalyst Résumé : Carbon nanofibers (CNFs) were synthesized by catalytic chemical vapor deposition from acetylene from a series of supported Pt catalysts derived from Pt-containing Mg–Al layered double hydroxide precursors. The materials were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, temperature programmed reduction, low-temperature N2 adsorption–desorption experiments, X-ray photoelectron spectroscopy, and Raman spectroscopy. The effects of reaction temperature and Pt content on the morphologies and microstructures of CNFs were investigated. The results revealed that the reaction temperature of 600 °C was appropriate for the growth of uniform CNFs with regular shape. Furthermore, the structural defects and the diameters of CNFs were reduced with the increasing Pt content, which is attributable to the high dispersion of smaller Pt nanoparticles as well as the quick deposition rate of carbon atoms on active metal particles. The present work developed an additional approach to optimize the growth of CNFs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395850

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Catalytic wet air oxidation of p-coumaric acid overcarbon nanotubes and activated carbon / Candida Milone in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp 9043–9053 Titre : Catalytic wet air oxidation of p-coumaric acid overcarbon nanotubes and activated carbon Type de document : texte imprimé Auteurs : Candida Milone, Auteur ; Abdul Rahim Shahul Hameed, Auteur ; Elpida Piperopoulos, Auteur Année de publication : 2011 Article en page(s) : pp 9043–9053 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Transition metal Olive Food industry Waste water Environmental protection Catalyst support Heterogeneous catalysis Supported catalyst Gold Platinum Cerium oxide Lanthanide compound Oxidation Wet air Catalytic reaction Résumé : p-Coumaric acid is representative of the polyphenolic fraction typically found in olive milling waste waters (OMWW). The catalytic wet air oxidation of p-coumaric acid has been investigated at 353 K at P = 2 MPa, using CeO2, Pt and Au supported on CeO2 catalysts. The influence of the metal and of the preparation method of the catalysts on the catalytic activity has been investigated. Upon addition of Pt to CeO2, the rate of oxidation of p-coumaric acid increases whereas addition of gold do not lead to a significant difference of the activity of CeO2. On all the catalysts investigated, the abatement of total organic carbon (TOC) was >80% after 300 min of reaction. Catalysts containing metallic platinum are the most effective towards the mineralization of the organic carbon to CO2 and the degree of mineralization (DM%) was higher than 50%. On CeO2 and Au-CeO2 catalysts a great contribute to the abatement of TOC is given from a significant adsorption of the organic substrates on the solid. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=18193885 [article] Catalytic wet air oxidation of p-coumaric acid overcarbon nanotubes and activated carbon [texte imprimé] / Candida Milone, Auteur ; Abdul Rahim Shahul Hameed, Auteur ; Elpida Piperopoulos, Auteur . - 2011 . - pp 9043–9053. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp 9043–9053 Mots-clés : Transition metal Olive Food industry Waste water Environmental protection Catalyst support Heterogeneous catalysis Supported catalyst Gold Platinum Cerium oxide Lanthanide compound Oxidation Wet air Catalytic reaction Résumé : p-Coumaric acid is representative of the polyphenolic fraction typically found in olive milling waste waters (OMWW). The catalytic wet air oxidation of p-coumaric acid has been investigated at 353 K at P = 2 MPa, using CeO2, Pt and Au supported on CeO2 catalysts. The influence of the metal and of the preparation method of the catalysts on the catalytic activity has been investigated. Upon addition of Pt to CeO2, the rate of oxidation of p-coumaric acid increases whereas addition of gold do not lead to a significant difference of the activity of CeO2. On all the catalysts investigated, the abatement of total organic carbon (TOC) was >80% after 300 min of reaction. Catalysts containing metallic platinum are the most effective towards the mineralization of the organic carbon to CO2 and the degree of mineralization (DM%) was higher than 50%. On CeO2 and Au-CeO2 catalysts a great contribute to the abatement of TOC is given from a significant adsorption of the organic substrates on the solid. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=18193885

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Kinetic modeling of the free-radical process during the initiated thermal cracking of normal alkanes with 1-nitropropane as an initiator / Yulei Guan in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9054-9062 Titre : Kinetic modeling of the free-radical process during the initiated thermal cracking of normal alkanes with 1-nitropropane as an initiator Type de document : texte imprimé Auteurs : Yulei Guan, Auteur ; Bolun Yang, Auteur ; Suitao Qi, Auteur Année de publication : 2011 Article en page(s) : pp. 9054-9062 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Modeling Thermal cracking Free radical Kinetic model Résumé : To elucidate the accelerating effect of 1-nitropropane on the thennal cracking of normal alkanes, ab initio and density functional theory calculations were performed to investigate the elementary reactions involved in the initiated thermal cracking of a 1-nitropropane/n-heptane mixture. The kinetic parameters were evaluated on the basis of standard transition state theory (TST) or variational transition state theory (VTST) with Wigner tunneling correction. The activation energy for the C-N bond rupture of 1-nitropropane to produce primary n-propyl and nitro radicals is calculated to be 234-269 kJ/mol, while the bond dissociation energy of the C-C bond within the n-heptane molecule is predicted to be at least 335 kJ/mol. These calculated results demonstrate that the presence of 1-nitropropane makes the free radical formation become relatively easier compared with single n-heptane cracking. Furthermore, compared with the C-H bond cleavage and 1,3-H intramolecular transfer, the unstable n-propyl radical mainly follows the C-C bond cleavage pathway to produce ethylene and secondary CH3 radical. After formation of these free radicals, the H-abstraction of n-heptane with radicals occurs readily with considerably lower activation energy than the radical formation step to initiate the chain reaction. The analysis result indicates that the thermal cracking of n-heptane is accelerated mainly due to the change of the initial step from the C-C bond cleavage of n-heptane to the C-N bond rupture of 1-nitropropane. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395852 [article] Kinetic modeling of the free-radical process during the initiated thermal cracking of normal alkanes with 1-nitropropane as an initiator [texte imprimé] / Yulei Guan, Auteur ; Bolun Yang, Auteur ; Suitao Qi, Auteur . - 2011 . - pp. 9054-9062. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9054-9062 Mots-clés : Modeling Thermal cracking Free radical Kinetic model Résumé : To elucidate the accelerating effect of 1-nitropropane on the thennal cracking of normal alkanes, ab initio and density functional theory calculations were performed to investigate the elementary reactions involved in the initiated thermal cracking of a 1-nitropropane/n-heptane mixture. The kinetic parameters were evaluated on the basis of standard transition state theory (TST) or variational transition state theory (VTST) with Wigner tunneling correction. The activation energy for the C-N bond rupture of 1-nitropropane to produce primary n-propyl and nitro radicals is calculated to be 234-269 kJ/mol, while the bond dissociation energy of the C-C bond within the n-heptane molecule is predicted to be at least 335 kJ/mol. These calculated results demonstrate that the presence of 1-nitropropane makes the free radical formation become relatively easier compared with single n-heptane cracking. Furthermore, compared with the C-H bond cleavage and 1,3-H intramolecular transfer, the unstable n-propyl radical mainly follows the C-C bond cleavage pathway to produce ethylene and secondary CH3 radical. After formation of these free radicals, the H-abstraction of n-heptane with radicals occurs readily with considerably lower activation energy than the radical formation step to initiate the chain reaction. The analysis result indicates that the thermal cracking of n-heptane is accelerated mainly due to the change of the initial step from the C-C bond cleavage of n-heptane to the C-N bond rupture of 1-nitropropane. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395852

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Effect of microwave treatment on structural changes and gasification reactivity of petroleum coke / Xin Liu in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9063-9068 Titre : Effect of microwave treatment on structural changes and gasification reactivity of petroleum coke Type de document : texte imprimé Auteurs : Xin Liu, Auteur ; Zhi-jie Zhou, Auteur ; Bao-shen Zhang, Auteur Année de publication : 2011 Article en page(s) : pp. 9063-9068 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Petroleum Chemical reactivity Gasification Microwave Résumé : The gasification reactivity of petroleum coke, which was treated by microwave at different times, powers, and temperatures, was investigated by using thermogravimetric analysis (TGA) at 1473 K at atmospheric pressure. The results showed that the gasification rate of petroleum coke increased with the increase of conversion and then decreased after reaching its maximum; the conversion corresponding to the maximal gasification rate is about x=0.1. The gasification rate of petroleum coke increased with the increase of microwave irradiation time and irradiation power, but as the irradiation temperature increased, the gasification rate of petroleum coke first increased and then decreased. Petroleum coke before and after microwave treatment was analyzed by X-ray diffraction (XRD), infrared absorption spectroscopy (IR), and the accelerated surface area and porosimetry system (ASAP). The results showed that the crystalline structure of petroleum coke becomes amorphous and the BET surface area and pore volume become larger with increase of microwave irradiation time and irradiation power. As the irradiation temperature increased, the crystalline ordering degree of petroleum coke became weakened and then strengthened and the BET surface area and pore volume increased and then decreased, which agrees with the change in the petroleum coke gasification reaction rate. Results show that microwave treatment is an effective way to change the structure of petroleum coke and promote its gasification reactivity. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395853 [article] Effect of microwave treatment on structural changes and gasification reactivity of petroleum coke [texte imprimé] / Xin Liu, Auteur ; Zhi-jie Zhou, Auteur ; Bao-shen Zhang, Auteur . - 2011 . - pp. 9063-9068. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9063-9068 Mots-clés : Petroleum Chemical reactivity Gasification Microwave Résumé : The gasification reactivity of petroleum coke, which was treated by microwave at different times, powers, and temperatures, was investigated by using thermogravimetric analysis (TGA) at 1473 K at atmospheric pressure. The results showed that the gasification rate of petroleum coke increased with the increase of conversion and then decreased after reaching its maximum; the conversion corresponding to the maximal gasification rate is about x=0.1. The gasification rate of petroleum coke increased with the increase of microwave irradiation time and irradiation power, but as the irradiation temperature increased, the gasification rate of petroleum coke first increased and then decreased. Petroleum coke before and after microwave treatment was analyzed by X-ray diffraction (XRD), infrared absorption spectroscopy (IR), and the accelerated surface area and porosimetry system (ASAP). The results showed that the crystalline structure of petroleum coke becomes amorphous and the BET surface area and pore volume become larger with increase of microwave irradiation time and irradiation power. As the irradiation temperature increased, the crystalline ordering degree of petroleum coke became weakened and then strengthened and the BET surface area and pore volume increased and then decreased, which agrees with the change in the petroleum coke gasification reaction rate. Results show that microwave treatment is an effective way to change the structure of petroleum coke and promote its gasification reactivity. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395853

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Supported undecaphosphotungstate / Pragati A Shringarpure in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9069-9076 Titre : Supported undecaphosphotungstate : an ecofriendly and efficient solid catalyst for nonsolvent liquid-phase aerobic epoxidation of alkenes Type de document : texte imprimé Auteurs : Pragati A Shringarpure, Auteur ; Anjali Patel, Auteur Année de publication : 2011 Article en page(s) : pp. 9069-9076 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Epoxidation Aerobe Liquid phase Catalyst Résumé : An ecofriendly solid catalytic system comprising undecaphosphotungstate and neutral alumina was found to be an efficient catalytic system for solvent-free liquid-phase aerobic epoxidation of alkenes under mild reaction conditions. The superiority of the present catalyst lies in achieving 85% conversion for cyclohexene with 100% selectivity toward cyclohexene oxide. Further, the catalyst can be regenerated and can be reused up to three cycles without any significant loss in the catalytic activity. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395854 [article] Supported undecaphosphotungstate : an ecofriendly and efficient solid catalyst for nonsolvent liquid-phase aerobic epoxidation of alkenes [texte imprimé] / Pragati A Shringarpure, Auteur ; Anjali Patel, Auteur . - 2011 . - pp. 9069-9076. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9069-9076 Mots-clés : Epoxidation Aerobe Liquid phase Catalyst Résumé : An ecofriendly solid catalytic system comprising undecaphosphotungstate and neutral alumina was found to be an efficient catalytic system for solvent-free liquid-phase aerobic epoxidation of alkenes under mild reaction conditions. The superiority of the present catalyst lies in achieving 85% conversion for cyclohexene with 100% selectivity toward cyclohexene oxide. Further, the catalyst can be regenerated and can be reused up to three cycles without any significant loss in the catalytic activity. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395854

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Modeling and experimental verification of a corrugated plate photocatalytic reactor using computational fluid dynamics / Claudio Passalia in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9077–9086 Titre : Modeling and experimental verification of a corrugated plate photocatalytic reactor using computational fluid dynamics Type de document : texte imprimé Auteurs : Claudio Passalia, Auteur ; Orlando M. Alfano, Auteur ; Rodolfo J. Brandi, Auteur Année de publication : 2011 Article en page(s) : pp. 9077–9086 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Photocatalytic Computational fluid dynamics Résumé : Heterogeneous photocatalysis is a suitable technology for eliminating indoor pollutants at low concentration ranges. In this work we deal with the modeling and experimental evaluation of a continuous, single-pass, corrugated plate photocatalytic reactor for elimination of gaseous formaldehyde in air. The reactor configuration consists of a corrugated stainless steel plate coated with titanium dioxide catalyst, irradiated from both sides with UV lamps. The complete modeling of the reactor was achieved by means of a commercial CFD tool. Nonetheless, the radiative transfer within the reactor was modeled externally, considering the lamps emission and the radiative interaction between reactor windows and catalytic walls by the computation of view factors. The reaction kinetics was also imposed externally from previous determined parameters. The conditions of the experimental runs were replicated in the computational simulations. Model predictions of the formaldehyde overall conversion showed good agreement with experiments, with a root-mean-square error less than 4%. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200756t [article] Modeling and experimental verification of a corrugated plate photocatalytic reactor using computational fluid dynamics [texte imprimé] / Claudio Passalia, Auteur ; Orlando M. Alfano, Auteur ; Rodolfo J. Brandi, Auteur . - 2011 . - pp. 9077–9086. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9077–9086 Mots-clés : Photocatalytic Computational fluid dynamics Résumé : Heterogeneous photocatalysis is a suitable technology for eliminating indoor pollutants at low concentration ranges. In this work we deal with the modeling and experimental evaluation of a continuous, single-pass, corrugated plate photocatalytic reactor for elimination of gaseous formaldehyde in air. The reactor configuration consists of a corrugated stainless steel plate coated with titanium dioxide catalyst, irradiated from both sides with UV lamps. The complete modeling of the reactor was achieved by means of a commercial CFD tool. Nonetheless, the radiative transfer within the reactor was modeled externally, considering the lamps emission and the radiative interaction between reactor windows and catalytic walls by the computation of view factors. The reaction kinetics was also imposed externally from previous determined parameters. The conditions of the experimental runs were replicated in the computational simulations. Model predictions of the formaldehyde overall conversion showed good agreement with experiments, with a root-mean-square error less than 4%. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200756t

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What does LiOH treatment offer for lyocell fibers? investigation of structural changes / Hale Bahar Ozturk in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9087-9094 Titre : What does LiOH treatment offer for lyocell fibers? investigation of structural changes Type de document : texte imprimé Auteurs : Hale Bahar Ozturk, Auteur ; Bill MacNaughtan, Auteur ; John R. Mitchell, Auteur Année de publication : 2011 Article en page(s) : pp. 9087-9094 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Lyocell fibers cellulosic Résumé : Lyocell fibers, regenerated cellulosic fibers spun from cellulose/N-methylmorpholine-N-oxide hydrate solution by wet spinning, were treated with LiOH aqueous solution at concentrations of up to 7.5 M to study the inter- and intrafibrillar changes. Wide-angle X-ray diffraction analyses were applied to identify the crystallinity index and crystallite size. Inverse size-exclusion chromatography was applied to study the pore structure of the swollen fibers. The mean pore diameter was found to increase after the LiOH treatment. The carboxyl content, measured by methylene blue sorption, decreased slightly. The water retention value, depth of color measured after dyeing with CI Direct Red 81, and weight loss of fibers changed gradually after LiOH treatment at concentrations up to ca. 5 M. The treated fibers became brittle as a result of both inter- and intrafibrillar swelling and the deep penetration ability of LiOH treatments above 5 M. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1015624 [article] What does LiOH treatment offer for lyocell fibers? investigation of structural changes [texte imprimé] / Hale Bahar Ozturk, Auteur ; Bill MacNaughtan, Auteur ; John R. Mitchell, Auteur . - 2011 . - pp. 9087-9094. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9087-9094 Mots-clés : Lyocell fibers cellulosic Résumé : Lyocell fibers, regenerated cellulosic fibers spun from cellulose/N-methylmorpholine-N-oxide hydrate solution by wet spinning, were treated with LiOH aqueous solution at concentrations of up to 7.5 M to study the inter- and intrafibrillar changes. Wide-angle X-ray diffraction analyses were applied to identify the crystallinity index and crystallite size. Inverse size-exclusion chromatography was applied to study the pore structure of the swollen fibers. The mean pore diameter was found to increase after the LiOH treatment. The carboxyl content, measured by methylene blue sorption, decreased slightly. The water retention value, depth of color measured after dyeing with CI Direct Red 81, and weight loss of fibers changed gradually after LiOH treatment at concentrations up to ca. 5 M. The treated fibers became brittle as a result of both inter- and intrafibrillar swelling and the deep penetration ability of LiOH treatments above 5 M. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1015624

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Biogenic silver nanoparticles by cacumen platycladi extract / Jiale Huang in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9095-9106 Titre : Biogenic silver nanoparticles by cacumen platycladi extract : synthesis, formation mechanism, and antibacterial activity Type de document : texte imprimé Auteurs : Jiale Huang, Auteur ; Guowu Zhan, Auteur ; Bingyun Zheng, Auteur Année de publication : 2011 Article en page(s) : pp. 9095-9106 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Formation mechanism Extract Nanoparticle Biogenic factor Résumé : Biosynthesis of Ag nanoparticles (AgNPs) by Cacumen Platycladi extract was investigated. The AgNPs were characterized by ultraviolet-visible absorption spectroscopy (UV-vis), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), and X-ray diffraction (XRD). The results showed that increasing the initial AgNO3 concentration at 30 or 60 °C increased the mean size and widened the size distribution of the AgNPs leading to red shift and broadening of the Surface Plasmon Resonance absorption. The conversion of silver ions was determined by atomic absorption spectroscopy (AAS) and to discuss the bioreductive mechanism, the reducing sugar, flavonoid, saccharide, protein contents in the extract, and the antioxidant activity were measured using 3,5-dinitrosalicylic acid colorimetric; Coomassie brilliant blue; phenol-sulfuric acid; rutin-based spectrophotometry method; and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging assay methods. The results showed that the reducing sugars and flavonoids were mainly responsible for the bioreduction of the silver ions and their reductive capability promoted at 90 °C, leading to the formation of AgNPs (18.4 ± 4.6 nm) with narrow size distribution. Finally, the antibacterial activity of the AgNPs against E. coli and S. aureus was assessed to determine their potential applications in silver-loaded antibacterial materials. This work provides useful technical parameters for industrialization ofthe biosynthetic technique and further antibacterial application of the AgNPs. Furthermore, the elucidation of bioreductive mechanism of silver ions by measuring the change of the biomolecular concentrations in plant extract exemplifies understanding the formation mechanism of such biogenic AgNPs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395857 [article] Biogenic silver nanoparticles by cacumen platycladi extract : synthesis, formation mechanism, and antibacterial activity [texte imprimé] / Jiale Huang, Auteur ; Guowu Zhan, Auteur ; Bingyun Zheng, Auteur . - 2011 . - pp. 9095-9106. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9095-9106 Mots-clés : Formation mechanism Extract Nanoparticle Biogenic factor Résumé : Biosynthesis of Ag nanoparticles (AgNPs) by Cacumen Platycladi extract was investigated. The AgNPs were characterized by ultraviolet-visible absorption spectroscopy (UV-vis), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), and X-ray diffraction (XRD). The results showed that increasing the initial AgNO3 concentration at 30 or 60 °C increased the mean size and widened the size distribution of the AgNPs leading to red shift and broadening of the Surface Plasmon Resonance absorption. The conversion of silver ions was determined by atomic absorption spectroscopy (AAS) and to discuss the bioreductive mechanism, the reducing sugar, flavonoid, saccharide, protein contents in the extract, and the antioxidant activity were measured using 3,5-dinitrosalicylic acid colorimetric; Coomassie brilliant blue; phenol-sulfuric acid; rutin-based spectrophotometry method; and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging assay methods. The results showed that the reducing sugars and flavonoids were mainly responsible for the bioreduction of the silver ions and their reductive capability promoted at 90 °C, leading to the formation of AgNPs (18.4 ± 4.6 nm) with narrow size distribution. Finally, the antibacterial activity of the AgNPs against E. coli and S. aureus was assessed to determine their potential applications in silver-loaded antibacterial materials. This work provides useful technical parameters for industrialization ofthe biosynthetic technique and further antibacterial application of the AgNPs. Furthermore, the elucidation of bioreductive mechanism of silver ions by measuring the change of the biomolecular concentrations in plant extract exemplifies understanding the formation mechanism of such biogenic AgNPs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395857

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Preparation of micronized β-HMX Using supercritical carbon dioxide as antisolvent / Byoung - Mine Lee in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9107-9115 Titre : Preparation of micronized β-HMX Using supercritical carbon dioxide as antisolvent Type de document : texte imprimé Auteurs : Byoung - Mine Lee, Auteur ; Soo - Jung Kim, Auteur ; Byung - Chul Lee, Auteur Année de publication : 2011 Article en page(s) : pp. 9107-9115 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Supercritical state Carbon dioxide Preparation Résumé : This study investigated the micronization of HMX (cyclotetramethylenetetranitramine) using two types of recrystallization methods with supercritical carbon dioxide as an antisolvent, namely, the aerosol solvent extraction system (ASES) and gas antisolvent (GAS) processes. The effects of experimental variables on the recrystallization of β-HMX particles in the GAS process were also studied. In particular, we varied the temperature from 303 to 323 K, used CO2 feeding rates of 20 and 50 mL·min-1, and varied the agitation speed from 200 to 900 rpm in the GAS process. The precipitated HMX particles were characterized by field-emission scanning electron microscopy (FE-SEM), particle size analysis (PSA), and Fourier transform infrared (FT-IR) spectroscopy. Depending on the organic solvent used and the type of recrystallization method, the precipitated HMX particles showed a variety of morphologies, particle size distributions, and crystal phases. The HMX precipitated by the ASES process was transformed into micronized γ- or δ-HMX with a volume-mean particle size (D50) of 6.3-32.1 μm. On the other hand, in the case of the GAS process, micronized γ- or β-HMX was formed, with a volume-mean particle size (D50) of 5.3-37.45 μm. In particular, HMX dissolved in acetone was successfully precipitated to micronized β-HMX with a narrow particle size distribution through the GAS process. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395858 [article] Preparation of micronized β-HMX Using supercritical carbon dioxide as antisolvent [texte imprimé] / Byoung - Mine Lee, Auteur ; Soo - Jung Kim, Auteur ; Byung - Chul Lee, Auteur . - 2011 . - pp. 9107-9115. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9107-9115 Mots-clés : Supercritical state Carbon dioxide Preparation Résumé : This study investigated the micronization of HMX (cyclotetramethylenetetranitramine) using two types of recrystallization methods with supercritical carbon dioxide as an antisolvent, namely, the aerosol solvent extraction system (ASES) and gas antisolvent (GAS) processes. The effects of experimental variables on the recrystallization of β-HMX particles in the GAS process were also studied. In particular, we varied the temperature from 303 to 323 K, used CO2 feeding rates of 20 and 50 mL·min-1, and varied the agitation speed from 200 to 900 rpm in the GAS process. The precipitated HMX particles were characterized by field-emission scanning electron microscopy (FE-SEM), particle size analysis (PSA), and Fourier transform infrared (FT-IR) spectroscopy. Depending on the organic solvent used and the type of recrystallization method, the precipitated HMX particles showed a variety of morphologies, particle size distributions, and crystal phases. The HMX precipitated by the ASES process was transformed into micronized γ- or δ-HMX with a volume-mean particle size (D50) of 6.3-32.1 μm. On the other hand, in the case of the GAS process, micronized γ- or β-HMX was formed, with a volume-mean particle size (D50) of 5.3-37.45 μm. In particular, HMX dissolved in acetone was successfully precipitated to micronized β-HMX with a narrow particle size distribution through the GAS process. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395858

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Effects of operational parameters on particle size distributions in methyl mpethacrylate suspension polymerization / Odinei H. Gonçalves in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9116-9122 Titre : Effects of operational parameters on particle size distributions in methyl mpethacrylate suspension polymerization Type de document : texte imprimé Auteurs : Odinei H. Gonçalves, Auteur ; André L. Nogueira, Auteur ; Pedro H. H. Araujo, Auteur Année de publication : 2011 Article en page(s) : pp. 9116-9122 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Suspension polymerization Particle size distribution Résumé : The correct manipulation of particle size distribution in suspension polymerization is important because particle size determines the product applicability and processability. Methyl methacrylate suspension polymerization was studied in order to determine the effect of operational parameters in manipulating the particle size distribution (PSD) while keeping suspension stability. The effects of stirring rate, stabilizer concentration, and stabilizer addition time were evaluated on particle size distribution, Sauter mean diameter, and suspension stability. Stabilizer concentration affected particle sizes but at the expense of system stability as low amounts of stabilizer led to uncontrolled coagulation of the particles. Changing the stirring rate was efficient in manipulating particle sizes although its increase led to the broadening of the PSDs while reducing the Sauter mean diameter. The moment stabilizer was fed has shown to be a very efficient way to manipulate the PSD as delaying the stabilizer addition increased the Sauter mean diameter and narrowed the distributions. However, there was a limit in increasing the addition time as adding the stabilizer at higher conversions compromised the suspension stability. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395859 [article] Effects of operational parameters on particle size distributions in methyl mpethacrylate suspension polymerization [texte imprimé] / Odinei H. Gonçalves, Auteur ; André L. Nogueira, Auteur ; Pedro H. H. Araujo, Auteur . - 2011 . - pp. 9116-9122. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9116-9122 Mots-clés : Suspension polymerization Particle size distribution Résumé : The correct manipulation of particle size distribution in suspension polymerization is important because particle size determines the product applicability and processability. Methyl methacrylate suspension polymerization was studied in order to determine the effect of operational parameters in manipulating the particle size distribution (PSD) while keeping suspension stability. The effects of stirring rate, stabilizer concentration, and stabilizer addition time were evaluated on particle size distribution, Sauter mean diameter, and suspension stability. Stabilizer concentration affected particle sizes but at the expense of system stability as low amounts of stabilizer led to uncontrolled coagulation of the particles. Changing the stirring rate was efficient in manipulating particle sizes although its increase led to the broadening of the PSDs while reducing the Sauter mean diameter. The moment stabilizer was fed has shown to be a very efficient way to manipulate the PSD as delaying the stabilizer addition increased the Sauter mean diameter and narrowed the distributions. However, there was a limit in increasing the addition time as adding the stabilizer at higher conversions compromised the suspension stability. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395859

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Preparation and rheological behaviors of thermoplastic poly(vinyl alcohol) modified by lactic acid / Jing Ding in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9123-9130 Titre : Preparation and rheological behaviors of thermoplastic poly(vinyl alcohol) modified by lactic acid Type de document : texte imprimé Auteurs : Jing Ding, Auteur ; Si - Chong Chen, Auteur ; Xiu-Li Wang, Auteur Année de publication : 2011 Article en page(s) : pp. 9123-9130 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Preparation Thermoplastic Résumé : A thermoplastic modified poly(vinyl alcohol) (PVA-g-LA) with improved melt processing property was prepared by melt polycondensation of PVA with lactic acid. Rheological behaviors of PVA-g-LA copolymers were investigated using a high-pressure capillary rheometer. The influences of the content of oligo-poly (lactic add) graft chains and content of PVA-0588 on the rheological properties of PVA-g-LA copolymers were researched. The rheological parameters including non-Newtonian index and the viscous flow activation energy were analyzed and evaluated. As predicted, the PVA-g-LA samples exhibited noticeable shear thinning behavior. The apparent viscosity, the viscous flow activation energy, and the non-Newtonian index of PVA-g-LA showed obvious correlation with the PLA grafting chain content and PVA-0588 content at a constant temperature and shear rate. Both the increase of the content of oligo-PLA graft chains and content of PVA-0588 with PVA-1799 can improve the melting flow processing of PVA-g-LA copolymer. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395860 [article] Preparation and rheological behaviors of thermoplastic poly(vinyl alcohol) modified by lactic acid [texte imprimé] / Jing Ding, Auteur ; Si - Chong Chen, Auteur ; Xiu-Li Wang, Auteur . - 2011 . - pp. 9123-9130. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9123-9130 Mots-clés : Preparation Thermoplastic Résumé : A thermoplastic modified poly(vinyl alcohol) (PVA-g-LA) with improved melt processing property was prepared by melt polycondensation of PVA with lactic acid. Rheological behaviors of PVA-g-LA copolymers were investigated using a high-pressure capillary rheometer. The influences of the content of oligo-poly (lactic add) graft chains and content of PVA-0588 on the rheological properties of PVA-g-LA copolymers were researched. The rheological parameters including non-Newtonian index and the viscous flow activation energy were analyzed and evaluated. As predicted, the PVA-g-LA samples exhibited noticeable shear thinning behavior. The apparent viscosity, the viscous flow activation energy, and the non-Newtonian index of PVA-g-LA showed obvious correlation with the PLA grafting chain content and PVA-0588 content at a constant temperature and shear rate. Both the increase of the content of oligo-PLA graft chains and content of PVA-0588 with PVA-1799 can improve the melting flow processing of PVA-g-LA copolymer. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395860

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Photocatalytic activity of TiO2 nanoparticles sensitized by culnS2 quantum dots / Fengyu Shen in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9131-9137 Titre : Photocatalytic activity of TiO2 nanoparticles sensitized by culnS2 quantum dots Type de document : texte imprimé Auteurs : Fengyu Shen, Auteur ; Wenxiu Que, Auteur ; Yulong Liao, Auteur Année de publication : 2011 Article en page(s) : pp. 9131-9137 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nanoparticle Titanium oxide Photocatalysis Résumé : In this paper, p-type CuInS2 quantum dots are synthesized by a solvothermal route and incorporated with n-type TiO2 nanoparticles by a thermal treatment process. Transmission electron microscopy (TEM) results indicate that the CuInS2 quantum dots distribute uniformly and the size is ~3.4 nm. Photocatalytic activities of the TiO2 nanoparticles sensitized with the CuInS2 quantum dots are evaluated by the degadation of the methyl orange aqueous solution under ultraviolet (UV) and visible (vis) light irradiation and show an enhanced performance, compared with the pure TiO2 nanoparticles and the pure CuInS2 quantum dots. Microstructural, morphological, and optical properties of the TiO2 nanoparticles sensitized with the CuInS2 quantum dots are characterized by X-ray diffraction (XRD) analysis, TEM, and UV-vis absorption spectroscopy. Results indicate that the CuInS2 quantum dots greatly enhance the absorption ofUV and visible light due to the p-n heterojunction being constructed between p-type CuInS2 quantum dots, and n-type TiO2 nanoparticles. Effects of the mass ratio of the TiO2 and CuInS2 and the thermal treatment temperature on the photocatalytic activities of the TiO2 nanoparticles sensitized with the CuInS2 quantum dots are also investigated. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395861 [article] Photocatalytic activity of TiO2 nanoparticles sensitized by culnS2 quantum dots [texte imprimé] / Fengyu Shen, Auteur ; Wenxiu Que, Auteur ; Yulong Liao, Auteur . - 2011 . - pp. 9131-9137. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9131-9137 Mots-clés : Nanoparticle Titanium oxide Photocatalysis Résumé : In this paper, p-type CuInS2 quantum dots are synthesized by a solvothermal route and incorporated with n-type TiO2 nanoparticles by a thermal treatment process. Transmission electron microscopy (TEM) results indicate that the CuInS2 quantum dots distribute uniformly and the size is ~3.4 nm. Photocatalytic activities of the TiO2 nanoparticles sensitized with the CuInS2 quantum dots are evaluated by the degadation of the methyl orange aqueous solution under ultraviolet (UV) and visible (vis) light irradiation and show an enhanced performance, compared with the pure TiO2 nanoparticles and the pure CuInS2 quantum dots. Microstructural, morphological, and optical properties of the TiO2 nanoparticles sensitized with the CuInS2 quantum dots are characterized by X-ray diffraction (XRD) analysis, TEM, and UV-vis absorption spectroscopy. Results indicate that the CuInS2 quantum dots greatly enhance the absorption ofUV and visible light due to the p-n heterojunction being constructed between p-type CuInS2 quantum dots, and n-type TiO2 nanoparticles. Effects of the mass ratio of the TiO2 and CuInS2 and the thermal treatment temperature on the photocatalytic activities of the TiO2 nanoparticles sensitized with the CuInS2 quantum dots are also investigated. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395861

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Adaptive agent-based system for process fault diagnosis / Sinem Perk in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9138-9155 Titre : Adaptive agent-based system for process fault diagnosis Type de document : texte imprimé Auteurs : Sinem Perk, Auteur ; Fouad Teymour, Auteur ; Ali Cinar, Auteur Année de publication : 2011 Article en page(s) : pp. 9138-9155 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Fault diagnostic Résumé : An adaptive agent-based hierarchical framework for fault type classification and diagnosis in continuous chemical processes is presented. Classification techniques such as Fisher's discriminant analysis (FDA) and partial least-squares discriminant analysis (PLSDA) and diagnosis tools such as variable contribution plots are used by agents in this supervision system. After an abnormality is detected, the classification results reported by different diagnosis agents are summarized via a performance-based criterion, and a consensus diagnosis decision is formed. In the agent management layer of the proposed system, the performances of diagnosis agents are evaluated under different fault scenarios, and the collective performance of the supervision system is improved via performance-based consensus decision and adaptation. The effectiveness of the proposed adaptive agent-based framework for the classification of faults is illustrated using a simulated continuous stirred tank reactor (CSTR) network. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395862 [article] Adaptive agent-based system for process fault diagnosis [texte imprimé] / Sinem Perk, Auteur ; Fouad Teymour, Auteur ; Ali Cinar, Auteur . - 2011 . - pp. 9138-9155. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9138-9155 Mots-clés : Fault diagnostic Résumé : An adaptive agent-based hierarchical framework for fault type classification and diagnosis in continuous chemical processes is presented. Classification techniques such as Fisher's discriminant analysis (FDA) and partial least-squares discriminant analysis (PLSDA) and diagnosis tools such as variable contribution plots are used by agents in this supervision system. After an abnormality is detected, the classification results reported by different diagnosis agents are summarized via a performance-based criterion, and a consensus diagnosis decision is formed. In the agent management layer of the proposed system, the performances of diagnosis agents are evaluated under different fault scenarios, and the collective performance of the supervision system is improved via performance-based consensus decision and adaptation. The effectiveness of the proposed adaptive agent-based framework for the classification of faults is illustrated using a simulated continuous stirred tank reactor (CSTR) network. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395862

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Scheduling gasoline blending operations from recipe determination to shipping using unit slots / Jie Li in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9156-9174 Titre : Scheduling gasoline blending operations from recipe determination to shipping using unit slots Type de document : texte imprimé Auteurs : Jie Li, Auteur ; Iftekhar A. Karimi, Auteur Année de publication : 2011 Article en page(s) : pp. 9156-9174 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Scheduling Résumé : Gasoline can yield 60%-70% of the total profit of a refinery. Integrated scheduling of gasoline blending and order delivery operations can increase profit by avoiding ship demurrage, improving customer satisfaction, minimizing quality giveaways, avoiding costly transitions and slop generation, and reducing inventory costs. In this paper, we develop a novel continuous-time formulation using unit slots for an integrated scheduling of gasoline blending operations incorporating features such as multipurpose tanks, parallel nonidentical blenders, minimum run lengths, blender setups, tank changeovers, piecewise-constant profiles for blend component qualities and feed rates, simultaneous receipt/delivery by tanks, etc. We employ and revise the schedule adjustment procedure of Li et aL [AIChE J. 2010, 56, 441-465] to avoid solving mixed-integer nonlinear programming (MINLP) problems and illustrate the effectiveness of our new formulation on 14 industry-scale examples. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395863 [article] Scheduling gasoline blending operations from recipe determination to shipping using unit slots [texte imprimé] / Jie Li, Auteur ; Iftekhar A. Karimi, Auteur . - 2011 . - pp. 9156-9174. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9156-9174 Mots-clés : Scheduling Résumé : Gasoline can yield 60%-70% of the total profit of a refinery. Integrated scheduling of gasoline blending and order delivery operations can increase profit by avoiding ship demurrage, improving customer satisfaction, minimizing quality giveaways, avoiding costly transitions and slop generation, and reducing inventory costs. In this paper, we develop a novel continuous-time formulation using unit slots for an integrated scheduling of gasoline blending operations incorporating features such as multipurpose tanks, parallel nonidentical blenders, minimum run lengths, blender setups, tank changeovers, piecewise-constant profiles for blend component qualities and feed rates, simultaneous receipt/delivery by tanks, etc. We employ and revise the schedule adjustment procedure of Li et aL [AIChE J. 2010, 56, 441-465] to avoid solving mixed-integer nonlinear programming (MINLP) problems and illustrate the effectiveness of our new formulation on 14 industry-scale examples. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395863

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Development of an online monitoring method of a CO2 capture process / Leon F. G. Geers in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9175-9180 Titre : Development of an online monitoring method of a CO2 capture process Type de document : texte imprimé Auteurs : Leon F. G. Geers, Auteur ; Annemieke Van de Runstraat, Auteur ; Ralph Joh, Auteur Année de publication : 2011 Article en page(s) : pp. 9175-9180 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Carbon dioxide Surveillance Résumé : One possible way to reduce our carbon footprint is using postcombustion capture (PCC) processes to remove CO2 from flue gases. Because of the highly dynamic characteristics of such processes, real-time performance monitoring is a very complex task. This paper presents a method for monitoring the concentrations of CO2, SOx, and a CO2 capturing agent (β-alanine) during a process in a PCC pilot plant. A partial least-squares (PLS) model was built to estimate these concentrations from Fourier transform infrared (FTIR) spectra of the capturing solvent during processing in a model PCC plant. The model predicts the species concentrations to within 0.05 mol/L, provided that the concentrations stayed within the calibration window of the model. Next to that, it is paramount that the solutions used for model calibration consist of the same solution matrix as the real process medium. The model was eventually used to monitor an emulated PCC process online during 24 h of processing. This demonstrated that events such as saturation of the capturing agent with CO2, water replenishment, and switching to safety protocols can be followed accurately. The combination of an FTIR spectrometer and a PLS model can be used to extract process information in real-time. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395864 [article] Development of an online monitoring method of a CO2 capture process [texte imprimé] / Leon F. G. Geers, Auteur ; Annemieke Van de Runstraat, Auteur ; Ralph Joh, Auteur . - 2011 . - pp. 9175-9180. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9175-9180 Mots-clés : Carbon dioxide Surveillance Résumé : One possible way to reduce our carbon footprint is using postcombustion capture (PCC) processes to remove CO2 from flue gases. Because of the highly dynamic characteristics of such processes, real-time performance monitoring is a very complex task. This paper presents a method for monitoring the concentrations of CO2, SOx, and a CO2 capturing agent (β-alanine) during a process in a PCC pilot plant. A partial least-squares (PLS) model was built to estimate these concentrations from Fourier transform infrared (FTIR) spectra of the capturing solvent during processing in a model PCC plant. The model predicts the species concentrations to within 0.05 mol/L, provided that the concentrations stayed within the calibration window of the model. Next to that, it is paramount that the solutions used for model calibration consist of the same solution matrix as the real process medium. The model was eventually used to monitor an emulated PCC process online during 24 h of processing. This demonstrated that events such as saturation of the capturing agent with CO2, water replenishment, and switching to safety protocols can be followed accurately. The combination of an FTIR spectrometer and a PLS model can be used to extract process information in real-time. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395864

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Design simulation of glass-fiber-loaded flow in an internally spout-fluidized bed for processing of thermoplastic composites. I. flow characterization / Yuan Zong in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9181-9196 Titre : Design simulation of glass-fiber-loaded flow in an internally spout-fluidized bed for processing of thermoplastic composites. I. flow characterization Type de document : texte imprimé Auteurs : Yuan Zong, Auteur ; Xiaogang Yang, Auteur ; Gance Dai, Auteur Année de publication : 2011 Article en page(s) : pp. 9181-9196 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Composite material Fluidized bed Fluidization Glass fiber Design Résumé : A novel fiber dispersion process suitable for the manufacture of composites consisting of long glass fibers and thermoplastic is discussed. An internally spout-fluidized bed with a draft tube and disk baffle has been designed to disperse fiber bundles and perform preimpregnation, which can improve the hydrodynamic behavior inside the spout-fluidized bed for more effective dispersion of fiber bundles and impregnation with resin powder when applying such beds in the manufacture of fiber-reinforced thermoplastics. Features of the flow field in the spout-fluidized bed are important for fiber dispersion. Therefore, this article discusses the design results in terms of numerical simulations [large-eddy simulations (LESs)], focusing on the likely hydrodynamic impact on fiber dispersion in this particular spout-fluidized bed. Because of a strong interaction between the flow in the spout-fluidized bed and the fibers in the actual process and the limitations on direct measurements of fiber floc breakup in the spout-fluidized bed, the strength of the fiber floc was obtained by strength measurements with a rheometer. In the LES runs, the motion of the fibers was neglected because of their low volume fraction (lower than 0.001%). The turbulence kinetic energy, Reynolds stress, and strain rate were determined by statistical analysis. The LES results clearly indicate that the addition of internals significantly alters the flow patterns in the spout-fluidized bed, in particular changing the characteristics of the round turbulent jet and confined impinging jet. The hydrodynamics analysis showed that the introduction of internals into a spout-fluidized bed improves its capacity and efficiency for dispersing fiber flocs. These results provide important information on the flow fields within spout-fluidized beds for process design and scaleup. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395865 [article] Design simulation of glass-fiber-loaded flow in an internally spout-fluidized bed for processing of thermoplastic composites. I. flow characterization [texte imprimé] / Yuan Zong, Auteur ; Xiaogang Yang, Auteur ; Gance Dai, Auteur . - 2011 . - pp. 9181-9196. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9181-9196 Mots-clés : Composite material Fluidized bed Fluidization Glass fiber Design Résumé : A novel fiber dispersion process suitable for the manufacture of composites consisting of long glass fibers and thermoplastic is discussed. An internally spout-fluidized bed with a draft tube and disk baffle has been designed to disperse fiber bundles and perform preimpregnation, which can improve the hydrodynamic behavior inside the spout-fluidized bed for more effective dispersion of fiber bundles and impregnation with resin powder when applying such beds in the manufacture of fiber-reinforced thermoplastics. Features of the flow field in the spout-fluidized bed are important for fiber dispersion. Therefore, this article discusses the design results in terms of numerical simulations [large-eddy simulations (LESs)], focusing on the likely hydrodynamic impact on fiber dispersion in this particular spout-fluidized bed. Because of a strong interaction between the flow in the spout-fluidized bed and the fibers in the actual process and the limitations on direct measurements of fiber floc breakup in the spout-fluidized bed, the strength of the fiber floc was obtained by strength measurements with a rheometer. In the LES runs, the motion of the fibers was neglected because of their low volume fraction (lower than 0.001%). The turbulence kinetic energy, Reynolds stress, and strain rate were determined by statistical analysis. The LES results clearly indicate that the addition of internals significantly alters the flow patterns in the spout-fluidized bed, in particular changing the characteristics of the round turbulent jet and confined impinging jet. The hydrodynamics analysis showed that the introduction of internals into a spout-fluidized bed improves its capacity and efficiency for dispersing fiber flocs. These results provide important information on the flow fields within spout-fluidized beds for process design and scaleup. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395865

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In-Situ product removal from fermentations by membrane extraction / Louise Heerema in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9197-9208 Titre : In-Situ product removal from fermentations by membrane extraction : conceptual process design and economics Type de document : texte imprimé Auteurs : Louise Heerema, Auteur ; Mark Roelands, Auteur ; Earl Goetheer, Auteur Année de publication : 2011 Article en page(s) : pp. 9197-9208 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Design Fermentation In situ Résumé : This paper describes a conceptual process design for the production of the model component phenol by a recombinant strain of the micro-organism Pseudomonas putida S12. The (bio)production of the inhibiting component phenol in a bioreactor is combined with direct product removal by membrane extraction (pertraction). Continuous fermentation with the pertraction unit inside the reactor (integrated process), is compared to fed-batch fermentation with the pertraction unit outside the reactor (nonintegrated process). In the nonintegrated process, the bioprocess is completely separated from the pertraction process. An extended model for fermentation, consisting of biomass growth and phenol production combined with product inhibition, cell removal, pertraction with 1-octanol, and regeneration of the solvent by distillation is described with the help of experimental and theoretical data. Running the fermentation process at a lower product concentration results in a more efficient substrate utilization into biomass and phenol. The disadvantage of the integrated process is the need for large distillation columns and a high energy input for solvent regeneration due to the low product concentration in the solvent and the high solvent fluxes. Economic evaluation of the two processes show that to obtain a return of investment of 15%, the product cost price of the integrated process is a factor three lower as compared to that of the nonintegrated process. The benefits of an integrated process will pay off even more for very toxic and inhibiting products that do not allow for a high concentration in the (bio)reactor as compared to phenol. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395866 [article] In-Situ product removal from fermentations by membrane extraction : conceptual process design and economics [texte imprimé] / Louise Heerema, Auteur ; Mark Roelands, Auteur ; Earl Goetheer, Auteur . - 2011 . - pp. 9197-9208. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9197-9208 Mots-clés : Design Fermentation In situ Résumé : This paper describes a conceptual process design for the production of the model component phenol by a recombinant strain of the micro-organism Pseudomonas putida S12. The (bio)production of the inhibiting component phenol in a bioreactor is combined with direct product removal by membrane extraction (pertraction). Continuous fermentation with the pertraction unit inside the reactor (integrated process), is compared to fed-batch fermentation with the pertraction unit outside the reactor (nonintegrated process). In the nonintegrated process, the bioprocess is completely separated from the pertraction process. An extended model for fermentation, consisting of biomass growth and phenol production combined with product inhibition, cell removal, pertraction with 1-octanol, and regeneration of the solvent by distillation is described with the help of experimental and theoretical data. Running the fermentation process at a lower product concentration results in a more efficient substrate utilization into biomass and phenol. The disadvantage of the integrated process is the need for large distillation columns and a high energy input for solvent regeneration due to the low product concentration in the solvent and the high solvent fluxes. Economic evaluation of the two processes show that to obtain a return of investment of 15%, the product cost price of the integrated process is a factor three lower as compared to that of the nonintegrated process. The benefits of an integrated process will pay off even more for very toxic and inhibiting products that do not allow for a high concentration in the (bio)reactor as compared to phenol. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395866

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Mixed succinic acid/acetic acid esterification with ethanol by reactive distillation. / Alvaro Orjuela in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9209-9220 Titre : Mixed succinic acid/acetic acid esterification with ethanol by reactive distillation. Type de document : texte imprimé Auteurs : Alvaro Orjuela, Auteur ; Aspi Kolah, Auteur ; Carl T. Lira, Auteur Année de publication : 2011 Article en page(s) : pp. 9209-9220 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Distillation with reaction Esterification Résumé : Esterification of mixtures of succinic acid and acetic acid, commonly produced via fermentation of biomass carbohydrates, with ethanol in a continuous reactive distillation unit has been studied. Experiments were carried out in a 6 m tall, 51 mm diameter pilot-scale stainless steel column with the reactive zone consisting of Katapak-SP11 structured packing containing Amberlyst 70 cation exchange resin as catalyst. Noncatalytic BX structured gauze packing was used in stripping and enrichment sections. Steady-state experiments were performed under different conditions by varying the composition and number of inlet streams, the column pressure, the reboiler power, and the reflux ratio. Conversions approaching 100% for both succinic acid and acetic acid were verified experimentally; succinate esters were obtained as bottom products with purities of diethyl succinate as high as 98%, and ethyl acetate was recovered in the distillate. Computer simulations based upon experimental phase equilibrium data and chemical kinetics were performed in Aspen Plus using RadFrac to reproduce steady-state results. Good agreement between experiment and simulation was observed under diverse operating conditions. The model developed here can be used to design commercial-scale systems for succinic acid production when acetic acid is also formed during the fermentation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395867 [article] Mixed succinic acid/acetic acid esterification with ethanol by reactive distillation. [texte imprimé] / Alvaro Orjuela, Auteur ; Aspi Kolah, Auteur ; Carl T. Lira, Auteur . - 2011 . - pp. 9209-9220. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9209-9220 Mots-clés : Distillation with reaction Esterification Résumé : Esterification of mixtures of succinic acid and acetic acid, commonly produced via fermentation of biomass carbohydrates, with ethanol in a continuous reactive distillation unit has been studied. Experiments were carried out in a 6 m tall, 51 mm diameter pilot-scale stainless steel column with the reactive zone consisting of Katapak-SP11 structured packing containing Amberlyst 70 cation exchange resin as catalyst. Noncatalytic BX structured gauze packing was used in stripping and enrichment sections. Steady-state experiments were performed under different conditions by varying the composition and number of inlet streams, the column pressure, the reboiler power, and the reflux ratio. Conversions approaching 100% for both succinic acid and acetic acid were verified experimentally; succinate esters were obtained as bottom products with purities of diethyl succinate as high as 98%, and ethyl acetate was recovered in the distillate. Computer simulations based upon experimental phase equilibrium data and chemical kinetics were performed in Aspen Plus using RadFrac to reproduce steady-state results. Good agreement between experiment and simulation was observed under diverse operating conditions. The model developed here can be used to design commercial-scale systems for succinic acid production when acetic acid is also formed during the fermentation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395867

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A New shortcut design method and economic analysis of divided wall columns / Kai-Ti Chu in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp.9221–9235 Titre : A New shortcut design method and economic analysis of divided wall columns Type de document : texte imprimé Auteurs : Kai-Ti Chu, Auteur ; Loic Cadoret, Auteur ; Cheng-Ching Yu, Auteur Année de publication : 2011 Article en page(s) : pp.9221–9235 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Wall Columns Résumé : Divided wall columns (DWCs) can save energy and capital costs compared with traditional distillation columns; however, the design of DWCs is more difficult because there are more degrees of freedom. This paper describes a novel short-cut method that can be used to rapidly determine near-optimal values of important design parameters, including the reflux ratio, number of stages in all sections, and split liquid and vapor ratios for the three most common types of DWCs. The method is based on the development of a rational and efficient net flow model and the application of the methods of Fenske, Underwood, and Gilliland and the Kirkbride equation. The method is applied to two real systems, and the results are compared with results from rigorous simulations and optimization. The results show that the shortcut method leads to a process similar to a feasible actual process, and the total annual cost (TAC) based on the design method is close to the minimum (optimum) total annual cost. The results also show that the method also provides good initial values for rigorous optimization. The method is also applied to a fictitious process consisting of three components with constant relative volatilities, for different values of the ease of separation index (ESI), overall split difficulty, and feed composition. The results indicate that the method works well for a variety of process conditions and that the minimum vapor flow rate is a good surrogate for the total cost of process operation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200234p [article] A New shortcut design method and economic analysis of divided wall columns [texte imprimé] / Kai-Ti Chu, Auteur ; Loic Cadoret, Auteur ; Cheng-Ching Yu, Auteur . - 2011 . - pp.9221–9235. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp.9221–9235 Mots-clés : Wall Columns Résumé : Divided wall columns (DWCs) can save energy and capital costs compared with traditional distillation columns; however, the design of DWCs is more difficult because there are more degrees of freedom. This paper describes a novel short-cut method that can be used to rapidly determine near-optimal values of important design parameters, including the reflux ratio, number of stages in all sections, and split liquid and vapor ratios for the three most common types of DWCs. The method is based on the development of a rational and efficient net flow model and the application of the methods of Fenske, Underwood, and Gilliland and the Kirkbride equation. The method is applied to two real systems, and the results are compared with results from rigorous simulations and optimization. The results show that the shortcut method leads to a process similar to a feasible actual process, and the total annual cost (TAC) based on the design method is close to the minimum (optimum) total annual cost. The results also show that the method also provides good initial values for rigorous optimization. The method is also applied to a fictitious process consisting of three components with constant relative volatilities, for different values of the ease of separation index (ESI), overall split difficulty, and feed composition. The results indicate that the method works well for a variety of process conditions and that the minimum vapor flow rate is a good surrogate for the total cost of process operation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200234p

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Nonlinear modeling method applied to prediction of Hot metal silicon in the ironmaking blast furnace / Antti Nurkkala in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9236-9248 [ Titre : Nonlinear modeling method applied to prediction of Hot metal silicon in the ironmaking blast furnace Type de document : texte imprimé Auteurs : Antti Nurkkala, Auteur ; Frank Pettersson, Auteur ; Henrik Saxe, Auteur Année de publication : 2011 Article en page(s) : pp. 9236-9248 [ Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Blast furnace Prediction Modeling Non linear model Résumé : Feedforward neural networks have been established as versatile tools for nonlinear black-box modeling, but in many data-mining tasks the choice of relevant inputs and network complexity still constitute major challenges. Statistical tests for detecting relations between inputs and outputs proposed in the literature are largely based on the theory for linear systems, and laborious retraining combined with the risk of getting stuck in local minima make the application of exhaustive search through all possible network configurations impossible but for toy problems. This paper proposes a systematic method to tackle the problem where an output shall be estimated on the basis of a (large) set of potential inputs. Feedforward neural networks of multilayer perceptron type are used in the three-stage approach: First, starting from sufficiently large networks, an efficient pruning method is applied to detect potential model candidates. Next, the best results of the pruning runs are extracted by forming a Pareto-frontier, with the contradictory objectives of minimizing network complexity and estimation error. The networks on this frontier are considered to contain promising hidden nodes with their specific connections to relevant input variables. These hidden nodes are therefore optimally combined by mixed-integer linear programming to form a final set of neural network models, from which the user can select a model of suitable complexity. The modeling method is applied on an illustrative test example as well as on a complex modeling problem in the metallurgical industry, i.e., prediction of the silicon content of hot metal produced in a blast furnace. It is demonstrated to find relevant inputs and to yield parsimonious sparsely connected neural models of the output. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395869 [article] Nonlinear modeling method applied to prediction of Hot metal silicon in the ironmaking blast furnace [texte imprimé] / Antti Nurkkala, Auteur ; Frank Pettersson, Auteur ; Henrik Saxe, Auteur . - 2011 . - pp. 9236-9248 [. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9236-9248 [ Mots-clés : Blast furnace Prediction Modeling Non linear model Résumé : Feedforward neural networks have been established as versatile tools for nonlinear black-box modeling, but in many data-mining tasks the choice of relevant inputs and network complexity still constitute major challenges. Statistical tests for detecting relations between inputs and outputs proposed in the literature are largely based on the theory for linear systems, and laborious retraining combined with the risk of getting stuck in local minima make the application of exhaustive search through all possible network configurations impossible but for toy problems. This paper proposes a systematic method to tackle the problem where an output shall be estimated on the basis of a (large) set of potential inputs. Feedforward neural networks of multilayer perceptron type are used in the three-stage approach: First, starting from sufficiently large networks, an efficient pruning method is applied to detect potential model candidates. Next, the best results of the pruning runs are extracted by forming a Pareto-frontier, with the contradictory objectives of minimizing network complexity and estimation error. The networks on this frontier are considered to contain promising hidden nodes with their specific connections to relevant input variables. These hidden nodes are therefore optimally combined by mixed-integer linear programming to form a final set of neural network models, from which the user can select a model of suitable complexity. The modeling method is applied on an illustrative test example as well as on a complex modeling problem in the metallurgical industry, i.e., prediction of the silicon content of hot metal produced in a blast furnace. It is demonstrated to find relevant inputs and to yield parsimonious sparsely connected neural models of the output. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395869

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Hierarchically distributed fault detection and identification through dempster–shafer evidence fusion / Kaushik Ghosh in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9249-9269 Titre : Hierarchically distributed fault detection and identification through dempster–shafer evidence fusion Type de document : texte imprimé Auteurs : Kaushik Ghosh, Auteur ; Sathish Natarajan, Auteur ; Rajagopalan Srinivasan, Auteur Année de publication : 2011 Article en page(s) : pp. 9249-9269 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Failure detection Résumé : Due to the sheer size and complexity of modem chemical processes, single centralized monolithic monitoring strategies are not always well suited for detecting and identifying faults. In this paper, we propose a framework for distributed fault detection and identification (FDI), wherein the process is decomposed hierarchically into sections and subsections based on a process flow diagram. Multiple hierarchical FDI methods at varying levels of granularity are deployed to monitor the various sections and subsections of the process. The results from the individual FDI methods contain mutually nonexclusive fault classes at different levels of granularity. We propose an adaptation of the Dempster-Shafer evidence theory to combine these diagnostic results at different levels of abstraction. The key benefits of this scheme as demonstrated through two case studies-a simulated CSTR-distillation column system and the Tennessee Eastman challenge process-are improved diagnostic performance compared to individual FDI methods, robust localization of even novel faults, and a coherent explanation of the entire plant's state. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395870 [article] Hierarchically distributed fault detection and identification through dempster–shafer evidence fusion [texte imprimé] / Kaushik Ghosh, Auteur ; Sathish Natarajan, Auteur ; Rajagopalan Srinivasan, Auteur . - 2011 . - pp. 9249-9269. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9249-9269 Mots-clés : Failure detection Résumé : Due to the sheer size and complexity of modem chemical processes, single centralized monolithic monitoring strategies are not always well suited for detecting and identifying faults. In this paper, we propose a framework for distributed fault detection and identification (FDI), wherein the process is decomposed hierarchically into sections and subsections based on a process flow diagram. Multiple hierarchical FDI methods at varying levels of granularity are deployed to monitor the various sections and subsections of the process. The results from the individual FDI methods contain mutually nonexclusive fault classes at different levels of granularity. We propose an adaptation of the Dempster-Shafer evidence theory to combine these diagnostic results at different levels of abstraction. The key benefits of this scheme as demonstrated through two case studies-a simulated CSTR-distillation column system and the Tennessee Eastman challenge process-are improved diagnostic performance compared to individual FDI methods, robust localization of even novel faults, and a coherent explanation of the entire plant's state. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395870

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Adsorption thermodynamics and kinetics of uridine 5′-monophosphate on a gel-type anion exchange resin / Xiqun Zhou in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9270-9279 Titre : Adsorption thermodynamics and kinetics of uridine 5′-monophosphate on a gel-type anion exchange resin Type de document : texte imprimé Auteurs : Xiqun Zhou, Auteur ; Jiansheng Fan, Auteur ; Nan Li, Auteur Année de publication : 2011 Article en page(s) : pp. 9270-9279 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Anionic resin Kinetics Adsorption Résumé : The adsorption behavior of uridine 5'-monophosphate (UMP) on a gel-type anion-exchange resin SD3 at different temperatures was investigated by the batch method. The dissociation equilibrium of UMP in aqueous solution has been studied. Effects of solution pH, contact time, and initial concentrations of UMP on the adsorption have been discussed. Adsorption equilibrium data had been fitted to three different isotherms including Langmuir, Freundlich, and Sips isotherms, which have been widely used in biosorption processes, and the accuracy for all models has been evaluated by the residual-root-mean-square error. For adsorption kinetics, the adsorption rate of UMP on the resin was interpreted by the Fick model, first- and second-order kinetic models, and the adsorption process was found to be well represented by the Fick model. The solution diffusivities of UMP at different temperatures were estimated by the Wilke-Chang equation. The sorption process was found to be controlled by the intraparticle diffusion. The Fick model and Sips isotherm were chosen to simulate the concentration diffusion of UMP on SD3 resin during the adsorption process. An intraparticle two-dimensional profile of SD3 resin at 0, 1, 4, 15, and 25 min for 293.15, 303.15, and 313.15 K was shown with a satisfactory description of the adsorption process. The thermodynamic parameters such as Gibbs free energy and enthalpy and entropy changes were calculated, and the values indicated that the adsorption process of UMP on SD3 resin was spontaneous and endothermic. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395871 [article] Adsorption thermodynamics and kinetics of uridine 5′-monophosphate on a gel-type anion exchange resin [texte imprimé] / Xiqun Zhou, Auteur ; Jiansheng Fan, Auteur ; Nan Li, Auteur . - 2011 . - pp. 9270-9279. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9270-9279 Mots-clés : Anionic resin Kinetics Adsorption Résumé : The adsorption behavior of uridine 5'-monophosphate (UMP) on a gel-type anion-exchange resin SD3 at different temperatures was investigated by the batch method. The dissociation equilibrium of UMP in aqueous solution has been studied. Effects of solution pH, contact time, and initial concentrations of UMP on the adsorption have been discussed. Adsorption equilibrium data had been fitted to three different isotherms including Langmuir, Freundlich, and Sips isotherms, which have been widely used in biosorption processes, and the accuracy for all models has been evaluated by the residual-root-mean-square error. For adsorption kinetics, the adsorption rate of UMP on the resin was interpreted by the Fick model, first- and second-order kinetic models, and the adsorption process was found to be well represented by the Fick model. The solution diffusivities of UMP at different temperatures were estimated by the Wilke-Chang equation. The sorption process was found to be controlled by the intraparticle diffusion. The Fick model and Sips isotherm were chosen to simulate the concentration diffusion of UMP on SD3 resin during the adsorption process. An intraparticle two-dimensional profile of SD3 resin at 0, 1, 4, 15, and 25 min for 293.15, 303.15, and 313.15 K was shown with a satisfactory description of the adsorption process. The thermodynamic parameters such as Gibbs free energy and enthalpy and entropy changes were calculated, and the values indicated that the adsorption process of UMP on SD3 resin was spontaneous and endothermic. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395871

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Calcined Mg–al layered double hydroxides for uptake of trace levels of bromate from aqueous solution / Ramesh Chitrakar in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9280-9285 Titre : Calcined Mg–al layered double hydroxides for uptake of trace levels of bromate from aqueous solution Type de document : texte imprimé Auteurs : Ramesh Chitrakar, Auteur ; Akinari Sonoda, Auteur ; Yoji Makita, Auteur Année de publication : 2011 Article en page(s) : pp. 9280-9285 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Aqueous solution Uptake Calcination Résumé : Layered double hydroxides of Mg and Al (Mg-Al LDH) were synthesized with OH-, Cl-, or CO32- as charge compensating anions. The materials were calcined at 500 °C in air. The bromate uptakes of calcined and uncalcined LDH materials were investigated from 0.78 μmol/dm3 bromate solution. Results show that uncalcined LDH exhibited no bromate uptake, although calcined LDH exhibited bromate uptake: the initial bromate concentration of 0.78 μmol/dm3 decreased to less than 0.078 μmol/dm3, the maximum contaminant level established for bromate in drinking water. The rate of bromate uptake of calcined LDH was slow to attain equilibrium in 48 h. The bromate uptake data of calcined LDH agreed well with the Freundlich model. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395872 [article] Calcined Mg–al layered double hydroxides for uptake of trace levels of bromate from aqueous solution [texte imprimé] / Ramesh Chitrakar, Auteur ; Akinari Sonoda, Auteur ; Yoji Makita, Auteur . - 2011 . - pp. 9280-9285. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9280-9285 Mots-clés : Aqueous solution Uptake Calcination Résumé : Layered double hydroxides of Mg and Al (Mg-Al LDH) were synthesized with OH-, Cl-, or CO32- as charge compensating anions. The materials were calcined at 500 °C in air. The bromate uptakes of calcined and uncalcined LDH materials were investigated from 0.78 μmol/dm3 bromate solution. Results show that uncalcined LDH exhibited no bromate uptake, although calcined LDH exhibited bromate uptake: the initial bromate concentration of 0.78 μmol/dm3 decreased to less than 0.078 μmol/dm3, the maximum contaminant level established for bromate in drinking water. The rate of bromate uptake of calcined LDH was slow to attain equilibrium in 48 h. The bromate uptake data of calcined LDH agreed well with the Freundlich model. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395872

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Preparation of activated carbons with large specific surface areas from biomass corncob and their adsorption equilibrium for methane, carbon dioxide, nitrogen, and hydrogen / Yong Sun in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9286–9294 Titre : Preparation of activated carbons with large specific surface areas from biomass corncob and their adsorption equilibrium for methane, carbon dioxide, nitrogen, and hydrogen Type de document : texte imprimé Auteurs : Yong Sun, Auteur ; Paul A. Webley, Auteur Année de publication : 2011 Article en page(s) : pp. 9286–9294 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Activated Carbons Biomass Corncob Carbon Dioxide Résumé : Activated carbons were produced from agricultural waste corncob using K2CO3 and H3PO4 as activators. The optimal activation temperature for producing the largest BET specific surface area and pore volume of the carbon was 800 °C for K2CO3 activation (sample CK-800) and 500 °C for H3PO4 activation (sample CP-500). The maximum BET specific surface area and pore volume of the resultant carbons were 1450 m2/g and 1.1 cm3/g for K2CO3 activation and 1069 m2/g and 1.0 cm3/g for H3PO4 activation, respectively. The two produced carbons for high pressure carbon dioxide, methane, and nitrogen separation and hydrogen storage were closely investigated. The adsorption isotherm model based on the Toth equation together with the Benedict–Webb–Rubin (BWR) equation of state for determination of the gas phase fugacity provides a satisfactory representation of the high pressure carbon dioxide, methane, and nitrogen equilibrium adsorption. The adsorption isotherm model based on the Langmuir–Freundlich equation together with the Benedict–Webb–Rubin (BWR) equation of state for determination of the gas phase fugacity provides a satisfactory representation of the high pressure hydrogen adsorption. The preferential adsorption of CO2 on the two carbons indicates its selectivity in separation of CO2/CH4 and CO2/N2 mixtures. The hydrogen adsorption capacity of the CK-800 attained 0.34 wt % at 298 K and 60 bar, while CP-500 attained 0.29 wt % at room temperature when the full coverage of the solid surface by hydrogen is reached. The isosteric enthalpies of CK-800 for CO2, CH4, N2, and H2 are around 17, 18, 8, and 9 kJ/mol, respectively; those for CP-500 for CO2, CH4, N2, and H2 are around 13, 12, 9, and 6.5 kJ/mol, respectively. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1024003 [article] Preparation of activated carbons with large specific surface areas from biomass corncob and their adsorption equilibrium for methane, carbon dioxide, nitrogen, and hydrogen [texte imprimé] / Yong Sun, Auteur ; Paul A. Webley, Auteur . - 2011 . - pp. 9286–9294. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9286–9294 Mots-clés : Activated Carbons Biomass Corncob Carbon Dioxide Résumé : Activated carbons were produced from agricultural waste corncob using K2CO3 and H3PO4 as activators. The optimal activation temperature for producing the largest BET specific surface area and pore volume of the carbon was 800 °C for K2CO3 activation (sample CK-800) and 500 °C for H3PO4 activation (sample CP-500). The maximum BET specific surface area and pore volume of the resultant carbons were 1450 m2/g and 1.1 cm3/g for K2CO3 activation and 1069 m2/g and 1.0 cm3/g for H3PO4 activation, respectively. The two produced carbons for high pressure carbon dioxide, methane, and nitrogen separation and hydrogen storage were closely investigated. The adsorption isotherm model based on the Toth equation together with the Benedict–Webb–Rubin (BWR) equation of state for determination of the gas phase fugacity provides a satisfactory representation of the high pressure carbon dioxide, methane, and nitrogen equilibrium adsorption. The adsorption isotherm model based on the Langmuir–Freundlich equation together with the Benedict–Webb–Rubin (BWR) equation of state for determination of the gas phase fugacity provides a satisfactory representation of the high pressure hydrogen adsorption. The preferential adsorption of CO2 on the two carbons indicates its selectivity in separation of CO2/CH4 and CO2/N2 mixtures. The hydrogen adsorption capacity of the CK-800 attained 0.34 wt % at 298 K and 60 bar, while CP-500 attained 0.29 wt % at room temperature when the full coverage of the solid surface by hydrogen is reached. The isosteric enthalpies of CK-800 for CO2, CH4, N2, and H2 are around 17, 18, 8, and 9 kJ/mol, respectively; those for CP-500 for CO2, CH4, N2, and H2 are around 13, 12, 9, and 6.5 kJ/mol, respectively. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1024003

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Surfactant-template/ultrasound-assisted method for the preparation of porous nanoparticle lithium zirconate / Hamid R. Radfarnia in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9295-9305 Titre : Surfactant-template/ultrasound-assisted method for the preparation of porous nanoparticle lithium zirconate Type de document : texte imprimé Auteurs : Hamid R. Radfarnia, Auteur ; Maria C. Iliuta, Auteur Année de publication : 2011 Article en page(s) : pp. 9295-9305 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nanoparticle Preparation Ultrasound Surfactant Résumé : Porous nanoparticle lithium zirconate (Li2ZrO3) was prepared using an ultrasound-assisted surfactant-template method in the liquid-state reaction. The CO2 adsorption performance of the prepared materials was tested under various conditions and compared with that of Li2ZrO3 prepared by the simple surfactant-template method (porous, without sonication) and the conventional soft-chemistry route. The results indicated a better adsorption rate and capacity of porous nanopowders, whether assisted with ultrasound or not, in comparison with the traditional sample. This behavior is mainly due to a less aggregated powder structure and porous framework, facilitating gas and ion diffusion to and from the particle layers. However, the porous adsorbent prepared without sonication exhibited instability during cyclic operation, limiting its application for long-time use. Sonication time and surfactant concentration were found to be key parameters for controlling the crystallite size and the BET surface area. The porous Li2ZrO3 sample prepared with less surfactant and a shorter irradiation time (sample A) had the most favorable sorption kinetics and capacity among all studied samples. The maximum uptake capacity of 22 wt % for sample A compared to 15.2 wt % for the conventional sample (sample J, fabricated by the soft-chemistry method), obtained under a 100% CO2 stream, suggested a noticeable improvement in sorption behavior of the proposed adsorbents compared with traditional Li2ZrO3. Moreover, the adequate cyclic stability of porous powders prepared by sonication identify these materials as promising CO2 acceptors, particularly for integrated sorbent/catalyst systems such as that used for sorption-enhanced steam methane reforming (SESMR). CO2 adsorption experimental data for sample A were successfully modeled at various CO2 partial pressures using a double-exponential equation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395874 [article] Surfactant-template/ultrasound-assisted method for the preparation of porous nanoparticle lithium zirconate [texte imprimé] / Hamid R. Radfarnia, Auteur ; Maria C. Iliuta, Auteur . - 2011 . - pp. 9295-9305. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9295-9305 Mots-clés : Nanoparticle Preparation Ultrasound Surfactant Résumé : Porous nanoparticle lithium zirconate (Li2ZrO3) was prepared using an ultrasound-assisted surfactant-template method in the liquid-state reaction. The CO2 adsorption performance of the prepared materials was tested under various conditions and compared with that of Li2ZrO3 prepared by the simple surfactant-template method (porous, without sonication) and the conventional soft-chemistry route. The results indicated a better adsorption rate and capacity of porous nanopowders, whether assisted with ultrasound or not, in comparison with the traditional sample. This behavior is mainly due to a less aggregated powder structure and porous framework, facilitating gas and ion diffusion to and from the particle layers. However, the porous adsorbent prepared without sonication exhibited instability during cyclic operation, limiting its application for long-time use. Sonication time and surfactant concentration were found to be key parameters for controlling the crystallite size and the BET surface area. The porous Li2ZrO3 sample prepared with less surfactant and a shorter irradiation time (sample A) had the most favorable sorption kinetics and capacity among all studied samples. The maximum uptake capacity of 22 wt % for sample A compared to 15.2 wt % for the conventional sample (sample J, fabricated by the soft-chemistry method), obtained under a 100% CO2 stream, suggested a noticeable improvement in sorption behavior of the proposed adsorbents compared with traditional Li2ZrO3. Moreover, the adequate cyclic stability of porous powders prepared by sonication identify these materials as promising CO2 acceptors, particularly for integrated sorbent/catalyst systems such as that used for sorption-enhanced steam methane reforming (SESMR). CO2 adsorption experimental data for sample A were successfully modeled at various CO2 partial pressures using a double-exponential equation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395874

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CO2 absorption characteristics in aqueous K2CO3/Piperazine solution by NMR spectroscopy / Young Eun Kim in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9306-9313 Titre : CO2 absorption characteristics in aqueous K2CO3/Piperazine solution by NMR spectroscopy Type de document : texte imprimé Auteurs : Young Eun Kim, Auteur ; Jeong Ho Choi, Auteur ; Sung Chan Nam, Auteur Année de publication : 2011 Article en page(s) : pp. 9306-9313 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : NMR spectrometry Gas absorption Carbon dioxide Résumé : This research studied the absorption of CO2 into the aqueous solution of piperazine (PZ) and K2CO3/PZ in the vapor-liquid equilibrium (VLE) apparatus at 313, 333, and 353 K. NMR spectroscopy was used to identify the species distribution in PZ-H2O-CO2 and K2CO3-PZ-H2O-CO2 systems. The study of species distribution is important for designing new absorbents and absorption processes for CO2 capture. The CO2 loaded solutions of PZ 7.5 wt % and K2CO3 15 wt %/PZ 7.5 wt % were prepared by VLE apparatus at 333 K. 1H NMR and 13C NMR spectra were obtained for these systems at 293 K. This study shows that it is possible to use this method to confirm the reaction mechanism of aqueous PZ and K2CO3/PZ solutions with CO2. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395875 [article] CO2 absorption characteristics in aqueous K2CO3/Piperazine solution by NMR spectroscopy [texte imprimé] / Young Eun Kim, Auteur ; Jeong Ho Choi, Auteur ; Sung Chan Nam, Auteur . - 2011 . - pp. 9306-9313. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9306-9313 Mots-clés : NMR spectrometry Gas absorption Carbon dioxide Résumé : This research studied the absorption of CO2 into the aqueous solution of piperazine (PZ) and K2CO3/PZ in the vapor-liquid equilibrium (VLE) apparatus at 313, 333, and 353 K. NMR spectroscopy was used to identify the species distribution in PZ-H2O-CO2 and K2CO3-PZ-H2O-CO2 systems. The study of species distribution is important for designing new absorbents and absorption processes for CO2 capture. The CO2 loaded solutions of PZ 7.5 wt % and K2CO3 15 wt %/PZ 7.5 wt % were prepared by VLE apparatus at 333 K. 1H NMR and 13C NMR spectra were obtained for these systems at 293 K. This study shows that it is possible to use this method to confirm the reaction mechanism of aqueous PZ and K2CO3/PZ solutions with CO2. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395875

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Solubility of used frying oil in high pressure CO2-cosolvent mixtures / Jesusa Rincon in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9314-9323 Titre : Solubility of used frying oil in high pressure CO2-cosolvent mixtures Type de document : texte imprimé Auteurs : Jesusa Rincon, Auteur ; Rafael Camarillo, Auteur ; Luis Rodriguez, Auteur Année de publication : 2011 Article en page(s) : pp. 9314-9323 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Cosolvent Carbon dioxide Solubility Résumé : The solubility of used frying oil in high pressure CO2 modified with four cosolvents (ethanol, methanol, acetone, and hexane) has been determined using a dynamic flow method. The aim of the work has been to analyze and compare the oil solubilities in CO2-cosolvent mixtures to those attained with pure CO2 in order to determine how the use of cosolvents affects the recovery of the undegraded triglyceride fraction of the waste oil. Another objective has been to obtain an empirical correlation to predict these solubility data for further scale-up applications. The pressure, temperature, and concentration ranges used to investigate the cosolvent effect were 30-35 MPa, 313-353 K, and 0.05-0.1 g of cosolvent/g of solvent, respectively. In such ranges the classical empirical models cannot be used since they do not account for the presence of a cosolvent. Therefore, a modification of the classical empirical correlations is proposed by introducing a cosolvent-concentration-dependent term. The modified model can be used to estimate the used oil solubilities in solvent—cosolvent mixtures and provides a better agreement with the experimental data, compared to the earlier models. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395876 [article] Solubility of used frying oil in high pressure CO2-cosolvent mixtures [texte imprimé] / Jesusa Rincon, Auteur ; Rafael Camarillo, Auteur ; Luis Rodriguez, Auteur . - 2011 . - pp. 9314-9323. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9314-9323 Mots-clés : Cosolvent Carbon dioxide Solubility Résumé : The solubility of used frying oil in high pressure CO2 modified with four cosolvents (ethanol, methanol, acetone, and hexane) has been determined using a dynamic flow method. The aim of the work has been to analyze and compare the oil solubilities in CO2-cosolvent mixtures to those attained with pure CO2 in order to determine how the use of cosolvents affects the recovery of the undegraded triglyceride fraction of the waste oil. Another objective has been to obtain an empirical correlation to predict these solubility data for further scale-up applications. The pressure, temperature, and concentration ranges used to investigate the cosolvent effect were 30-35 MPa, 313-353 K, and 0.05-0.1 g of cosolvent/g of solvent, respectively. In such ranges the classical empirical models cannot be used since they do not account for the presence of a cosolvent. Therefore, a modification of the classical empirical correlations is proposed by introducing a cosolvent-concentration-dependent term. The modified model can be used to estimate the used oil solubilities in solvent—cosolvent mixtures and provides a better agreement with the experimental data, compared to the earlier models. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395876

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Improving the heat integration of distillation columns in a cryogenic air separation unit / L. V. Van der Ham in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9324-9338 Titre : Improving the heat integration of distillation columns in a cryogenic air separation unit Type de document : texte imprimé Auteurs : L. V. Van der Ham, Auteur ; S. Kjelstrup, Auteur Année de publication : 2011 Article en page(s) : pp. 9324-9338 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Cryogenics Distillation column Heat recovery Résumé : The distillation columns of a two-column cryogenic air separation unit (ASU) are responsible for a considerable part of the total ASU inefficiencies. The efficiency of a conventional distillation column can be increased by distributing the reboiler and condenser duties over a larger part of its length. In an ASU, this can be realized by moving the low-pressure column (LPC) down along the high-pressure column (HPC), thus increasing the number of heat-integrated stages (HI stages). We present an assessment of the effect that such an intensification of the heat integration has on the performance of the ASU distillation section, using the entropy production as performance criterion. When keeping the operating pressures fixed, the entropy production in the LPC is replaced by entropy production in the HI stages, without affecting the total entropy production. Reducing the pressure ratio enables a reduction in the LPC entropy production without increasing the contribution of the HI stages. For a probable value of the heat-transfer capacity per stage, increasing the pressure in the LPC results in a decrease of 21% in the total entropy production, while decreasing the pressure in the HPC results in a decrease of 23%. Decreasing the pressure in the HPC when using an opportunistic heat-transfer capacity yields a decrease of 31%. The reductions in entropy production materialize eventually as changes in the required ASU compressor, pump, and expander duties. Compared to the addition of either an additional heat exchanger or an additional distillation column, the use of HI stages seems to be the most promising method for improving the thermodynamic performance of a cryogenic ASU. More-detailed experimental data are required to simulate heat-integrated distillation columns accurately. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395877 [article] Improving the heat integration of distillation columns in a cryogenic air separation unit [texte imprimé] / L. V. Van der Ham, Auteur ; S. Kjelstrup, Auteur . - 2011 . - pp. 9324-9338. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9324-9338 Mots-clés : Cryogenics Distillation column Heat recovery Résumé : The distillation columns of a two-column cryogenic air separation unit (ASU) are responsible for a considerable part of the total ASU inefficiencies. The efficiency of a conventional distillation column can be increased by distributing the reboiler and condenser duties over a larger part of its length. In an ASU, this can be realized by moving the low-pressure column (LPC) down along the high-pressure column (HPC), thus increasing the number of heat-integrated stages (HI stages). We present an assessment of the effect that such an intensification of the heat integration has on the performance of the ASU distillation section, using the entropy production as performance criterion. When keeping the operating pressures fixed, the entropy production in the LPC is replaced by entropy production in the HI stages, without affecting the total entropy production. Reducing the pressure ratio enables a reduction in the LPC entropy production without increasing the contribution of the HI stages. For a probable value of the heat-transfer capacity per stage, increasing the pressure in the LPC results in a decrease of 21% in the total entropy production, while decreasing the pressure in the HPC results in a decrease of 23%. Decreasing the pressure in the HPC when using an opportunistic heat-transfer capacity yields a decrease of 31%. The reductions in entropy production materialize eventually as changes in the required ASU compressor, pump, and expander duties. Compared to the addition of either an additional heat exchanger or an additional distillation column, the use of HI stages seems to be the most promising method for improving the thermodynamic performance of a cryogenic ASU. More-detailed experimental data are required to simulate heat-integrated distillation columns accurately. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395877

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Removal of trace olefins from aromatics at room temperature using pyridinium and imidazolium ionic liquids / Yu Sun in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9339-9343 Titre : Removal of trace olefins from aromatics at room temperature using pyridinium and imidazolium ionic liquids Type de document : texte imprimé Auteurs : Yu Sun, Auteur ; Li Shi, Auteur Année de publication : 2011 Article en page(s) : pp. 9339-9343 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ionic liquid Résumé : [BuPy]Br-AlCl3 and [BMIm]Br-AlCl3 were used to remove trace olefins from aromatics. At room temperature, almost 100% olefin conversion was obtained using [BuPy]Br-AlCl3 as the catalyst. The effects of the cation and the dosage of AlCl3 in the ionic liquid were investigated. It was found that the dosage of AlCl3 had a significant impact on the reaction, whereas the organic cation type mainly influenced the conversion. Anions in [BuPy]Br-AlCl3 such as AlCl4- and AlCl7- were shown to exist by ESI-MS, and the mechanism of the reaction catalyzed by [BuPy]Br-AlCl3 was studied. The investigation of various reaction parameters showed that the process saves time, consumes less energy, separates products more easily, and produces less pollution to the environment than conventional methods to remove trace olefins from aromatics. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395878 [article] Removal of trace olefins from aromatics at room temperature using pyridinium and imidazolium ionic liquids [texte imprimé] / Yu Sun, Auteur ; Li Shi, Auteur . - 2011 . - pp. 9339-9343. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9339-9343 Mots-clés : Ionic liquid Résumé : [BuPy]Br-AlCl3 and [BMIm]Br-AlCl3 were used to remove trace olefins from aromatics. At room temperature, almost 100% olefin conversion was obtained using [BuPy]Br-AlCl3 as the catalyst. The effects of the cation and the dosage of AlCl3 in the ionic liquid were investigated. It was found that the dosage of AlCl3 had a significant impact on the reaction, whereas the organic cation type mainly influenced the conversion. Anions in [BuPy]Br-AlCl3 such as AlCl4- and AlCl7- were shown to exist by ESI-MS, and the mechanism of the reaction catalyzed by [BuPy]Br-AlCl3 was studied. The investigation of various reaction parameters showed that the process saves time, consumes less energy, separates products more easily, and produces less pollution to the environment than conventional methods to remove trace olefins from aromatics. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395878

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CO2 Separation from flue gas using polyvinyl-(room temperature ionic liquid)–room temperature ionic liquid composite membranes / Pei Li in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9344-9353 Titre : CO2 Separation from flue gas using polyvinyl-(room temperature ionic liquid)–room temperature ionic liquid composite membranes Type de document : texte imprimé Auteurs : Pei Li, Auteur ; K. P. Pramoda, Auteur ; Tai-Shung Chung, Auteur Année de publication : 2011 Article en page(s) : pp. 9344-9353 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Composite material Ionic liquid Gaseous effluent Carbon dioxide Résumé : In this work, a vinyl-fonctionalized room temperature ionic liquid (RTIL), 1-vinyl-3-butylimidazolium bis-(trifluoromethylsulfonyl)imide ([vbim][Tf2N]), has been successfully synthesized. The RTIL was further polymerized and mixed with 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([bmim][Tf2N]) to form the free-standing poly([vbim]-[Tf2N])-[bmim][Tf2N] composite films. The compositions of [bmim] [Tf2N] in the composite membranes were designed at 15, 30, 45, and 60 wt %. The pristine poly([vbim][Tf2N]) and poly([vbim][Tf2N])-[bmim][Tf2N] composite membranes exhibit similar permeability selectivities as the standard [bmim][Tf2N] but permeabilities are enhanced up to 5 times higher than the equivalent polystyrene-RTIL and polyacrylate-RTIL membranes. An increase in [bmim][Tf2N] concentration of poly([vbim]-[Tf2N])-[bmim][Tf2N] composite membranes results in an increase in solubility, diffusivity, and permeability coefficients of CO2 and N2 but does not change the CO2/N2 selectivities of the solubility, diffusivity, and permeability. The CO2 permeability of the 60 wt % composite at 35°C, 10 atm is 559 barrers in pure gas tests which is closer to 60% of the [bmim][Tf2N] permeability (i.e., 1344 barrers). In addition, the 60 wt % composite membrane exhibits a CO2 permeability of 491.2 barrers and a CO2/N2 selectivity of 20 in mixed gas tests using CO2/N2 (50:50) as the feed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395879 [article] CO2 Separation from flue gas using polyvinyl-(room temperature ionic liquid)–room temperature ionic liquid composite membranes [texte imprimé] / Pei Li, Auteur ; K. P. Pramoda, Auteur ; Tai-Shung Chung, Auteur . - 2011 . - pp. 9344-9353. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9344-9353 Mots-clés : Composite material Ionic liquid Gaseous effluent Carbon dioxide Résumé : In this work, a vinyl-fonctionalized room temperature ionic liquid (RTIL), 1-vinyl-3-butylimidazolium bis-(trifluoromethylsulfonyl)imide ([vbim][Tf2N]), has been successfully synthesized. The RTIL was further polymerized and mixed with 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([bmim][Tf2N]) to form the free-standing poly([vbim]-[Tf2N])-[bmim][Tf2N] composite films. The compositions of [bmim] [Tf2N] in the composite membranes were designed at 15, 30, 45, and 60 wt %. The pristine poly([vbim][Tf2N]) and poly([vbim][Tf2N])-[bmim][Tf2N] composite membranes exhibit similar permeability selectivities as the standard [bmim][Tf2N] but permeabilities are enhanced up to 5 times higher than the equivalent polystyrene-RTIL and polyacrylate-RTIL membranes. An increase in [bmim][Tf2N] concentration of poly([vbim]-[Tf2N])-[bmim][Tf2N] composite membranes results in an increase in solubility, diffusivity, and permeability coefficients of CO2 and N2 but does not change the CO2/N2 selectivities of the solubility, diffusivity, and permeability. The CO2 permeability of the 60 wt % composite at 35°C, 10 atm is 559 barrers in pure gas tests which is closer to 60% of the [bmim][Tf2N] permeability (i.e., 1344 barrers). In addition, the 60 wt % composite membrane exhibits a CO2 permeability of 491.2 barrers and a CO2/N2 selectivity of 20 in mixed gas tests using CO2/N2 (50:50) as the feed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395879

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Improving the adsorption of heavy metals from water using commercial carbons modified with egg shell wastes / Alejandro Guijarro-Aldaco in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9354-9362 Titre : Improving the adsorption of heavy metals from water using commercial carbons modified with egg shell wastes Type de document : texte imprimé Auteurs : Alejandro Guijarro-Aldaco, Auteur ; Virginia Hernandez-Montoya, Auteur ; Adrian Bonilla-Petriciolet, Auteur Année de publication : 2011 Article en page(s) : pp. 9354-9362 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Heavy metal Adsorption Résumé : We introduce the application of hen egg shell waste to improve the adsorption capacities of heavy-metal ions using commercial carbons via the modification of their surface chemistry. Specifically, a calcium solution extracted from egg shell waste has been used as a low-cost activation agent to improve the adsorption properties of three commercial carbons. An orthogonal array of the Taguchi method has been applied to identify the optimal conditions for the adsorbent modification process using the Zn2+ batch adsorption, at 30 °C and pH 5, as the response variable. Our results show that maximum adsorption capacities of Cd2+, Ni2+, and Zn2+ ions, at 30 °C and pH 5, may increase up to 15 times, with respect to the results obtained using the commercial adsorbent without modification. The improvement of adsorbent performance may be related to the formation of calcium phosphate on the carbon surface. Finally, adsorption studies in binary metal solutions were performed to identify the competitive effects in multicomponent adsorption, using calcium-modified carbons. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395880 [article] Improving the adsorption of heavy metals from water using commercial carbons modified with egg shell wastes [texte imprimé] / Alejandro Guijarro-Aldaco, Auteur ; Virginia Hernandez-Montoya, Auteur ; Adrian Bonilla-Petriciolet, Auteur . - 2011 . - pp. 9354-9362. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9354-9362 Mots-clés : Heavy metal Adsorption Résumé : We introduce the application of hen egg shell waste to improve the adsorption capacities of heavy-metal ions using commercial carbons via the modification of their surface chemistry. Specifically, a calcium solution extracted from egg shell waste has been used as a low-cost activation agent to improve the adsorption properties of three commercial carbons. An orthogonal array of the Taguchi method has been applied to identify the optimal conditions for the adsorbent modification process using the Zn2+ batch adsorption, at 30 °C and pH 5, as the response variable. Our results show that maximum adsorption capacities of Cd2+, Ni2+, and Zn2+ ions, at 30 °C and pH 5, may increase up to 15 times, with respect to the results obtained using the commercial adsorbent without modification. The improvement of adsorbent performance may be related to the formation of calcium phosphate on the carbon surface. Finally, adsorption studies in binary metal solutions were performed to identify the competitive effects in multicomponent adsorption, using calcium-modified carbons. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395880

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Adsorption of thiophene on Pt/Ag-supported activated carbons prepared by ultrasonic-assisted impregnation / Xiao-lin Tang in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9363-9367 Titre : Adsorption of thiophene on Pt/Ag-supported activated carbons prepared by ultrasonic-assisted impregnation Type de document : texte imprimé Auteurs : Xiao-lin Tang, Auteur ; Wei Qian, Auteur ; An Hu, Auteur Année de publication : 2011 Article en page(s) : pp. 9363-9367 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Impregnation Activated carbon Adsorption Résumé : This work mainly involved the investigation of the adsorption of thiophene on Pt/Ag-supported activated carbons (ACs) prepared by ultrasonic-assisted impregnation (UI). The adsorption capacity of thiophene over the ACs studied followed the order of Pt/Ag/AC-UI > Ag/AC-UI > Ag/AC > AC > Pt/AC. Pt ions can promote the reaction between the soft acid Ag(I) and the soft base thiophene. These sorbents were characterized by X-ray diffraction (XRD), sorption of nitrogen (BET), and thermal analysis. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395881 [article] Adsorption of thiophene on Pt/Ag-supported activated carbons prepared by ultrasonic-assisted impregnation [texte imprimé] / Xiao-lin Tang, Auteur ; Wei Qian, Auteur ; An Hu, Auteur . - 2011 . - pp. 9363-9367. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9363-9367 Mots-clés : Impregnation Activated carbon Adsorption Résumé : This work mainly involved the investigation of the adsorption of thiophene on Pt/Ag-supported activated carbons (ACs) prepared by ultrasonic-assisted impregnation (UI). The adsorption capacity of thiophene over the ACs studied followed the order of Pt/Ag/AC-UI > Ag/AC-UI > Ag/AC > AC > Pt/AC. Pt ions can promote the reaction between the soft acid Ag(I) and the soft base thiophene. These sorbents were characterized by X-ray diffraction (XRD), sorption of nitrogen (BET), and thermal analysis. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395881

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One-step separation of platinum, palladium, and rhodium / Pinhua Yu in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9368-9376 Titre : One-step separation of platinum, palladium, and rhodium : a three-liquid-phase extraction approach Type de document : texte imprimé Auteurs : Pinhua Yu, Auteur ; Kun Huang, Auteur ; Chao Zhang, Auteur Année de publication : 2011 Article en page(s) : pp. 9368-9376 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Liquid phase Résumé : Three-liquid-phase extraction and one-step separation of platinum, palladium, and rhodium in the system composed of diisoamyl sulphide (S201), polyethylene oxide-polypropylene oxide random block copolymer (EOPO), Na2SO4, and H2O were investigated. Experimental results indicated that phase-forming salt type, salt concentrations, coexisting H+ and Cl- concentrations in equilibrious Na2SO4 aqueous solutions have significant influences on the three-liquid-phase partitioning behaviors of Pt(IV), Pd(II), and Rh(III). Under the optimized operation parameters, over 99 wt % of Pd(II), about 90 wt % of Pt(IV), and 85 wt % of Rh(III) in initial feed solutions were respectively concentrated into S201 top phase, EOPO middle phase, and Na2SO4 bottom aqueous phase. The present work explores a possibility to develop a three-liquid-phase extraction approach for one-step separation of platinum metal ions in highly concentrated acidic chloride media obtained by hydrometallurgical processes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395882 [article] One-step separation of platinum, palladium, and rhodium : a three-liquid-phase extraction approach [texte imprimé] / Pinhua Yu, Auteur ; Kun Huang, Auteur ; Chao Zhang, Auteur . - 2011 . - pp. 9368-9376. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9368-9376 Mots-clés : Liquid phase Résumé : Three-liquid-phase extraction and one-step separation of platinum, palladium, and rhodium in the system composed of diisoamyl sulphide (S201), polyethylene oxide-polypropylene oxide random block copolymer (EOPO), Na2SO4, and H2O were investigated. Experimental results indicated that phase-forming salt type, salt concentrations, coexisting H+ and Cl- concentrations in equilibrious Na2SO4 aqueous solutions have significant influences on the three-liquid-phase partitioning behaviors of Pt(IV), Pd(II), and Rh(III). Under the optimized operation parameters, over 99 wt % of Pd(II), about 90 wt % of Pt(IV), and 85 wt % of Rh(III) in initial feed solutions were respectively concentrated into S201 top phase, EOPO middle phase, and Na2SO4 bottom aqueous phase. The present work explores a possibility to develop a three-liquid-phase extraction approach for one-step separation of platinum metal ions in highly concentrated acidic chloride media obtained by hydrometallurgical processes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395882

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Dynamic performance of continuous-flow mixing of pseudoplastic fluids exhibiting yield stress in stirred reactors / Dineshkumar Patel in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9377–9389 Titre : Dynamic performance of continuous-flow mixing of pseudoplastic fluids exhibiting yield stress in stirred reactors Type de document : texte imprimé Auteurs : Dineshkumar Patel, Auteur ; Farhad Ein-Mozaffari, Auteur ; Mehrab Mehrvar, Auteur Année de publication : 2011 Article en page(s) : pp. 9377–9389 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Pseudoplastic fluids Résumé : The core objectives of this work were to characterize and optimize the continuous-flow mixing of pseudoplastic fluids exhibiting yield stress in stirred reactors. To achieve these objectives, the effects of impeller type (for the seven axial-flow impellers A100, A200, A310, A315, A320, 3AH, and 3AM and the four radial-flow impellers R500, RSB, RT, and Scaba), impeller speed (50–800 rpm), impeller diameter (T/3.2–T/1.6, where T is the tank diameter), impeller off-bottom clearance (H/3.4–H/1.7, where H is the fluid height in the vessel), inlet and outlet locations (for the four configurations top inlet–top outlet, top inlet–bottom outlet, bottom inlet–bottom outlet, and bottom inlet–top outlet), pumping directions for axial-flow impellers (upward and downward pumping), fluid height in the vessel (T/1.06–T/0.83), residence time (257–328 s), and jet velocity (0.317–3.24 m s–1) on the dynamic performance of the mixing vessel were explored. To identify nonideal flows, dynamic tests were conducted using the frequency-modulated random binary input of a brine solution with the feed. The mixing quality in the vessel was substantially improved by increasing the impeller diameter, increasing the residence time, optimizing the impeller off-bottom clearance, decreasing the fluid height, optimizing the jet velocity, and using the up-pumping axial-flow impeller. Applying these findings will lead to improved quality of products and more efficient use of power in continuous-flow mixing of yield-pseudoplastic fluids. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102388y [article] Dynamic performance of continuous-flow mixing of pseudoplastic fluids exhibiting yield stress in stirred reactors [texte imprimé] / Dineshkumar Patel, Auteur ; Farhad Ein-Mozaffari, Auteur ; Mehrab Mehrvar, Auteur . - 2011 . - pp. 9377–9389. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9377–9389 Mots-clés : Pseudoplastic fluids Résumé : The core objectives of this work were to characterize and optimize the continuous-flow mixing of pseudoplastic fluids exhibiting yield stress in stirred reactors. To achieve these objectives, the effects of impeller type (for the seven axial-flow impellers A100, A200, A310, A315, A320, 3AH, and 3AM and the four radial-flow impellers R500, RSB, RT, and Scaba), impeller speed (50–800 rpm), impeller diameter (T/3.2–T/1.6, where T is the tank diameter), impeller off-bottom clearance (H/3.4–H/1.7, where H is the fluid height in the vessel), inlet and outlet locations (for the four configurations top inlet–top outlet, top inlet–bottom outlet, bottom inlet–bottom outlet, and bottom inlet–top outlet), pumping directions for axial-flow impellers (upward and downward pumping), fluid height in the vessel (T/1.06–T/0.83), residence time (257–328 s), and jet velocity (0.317–3.24 m s–1) on the dynamic performance of the mixing vessel were explored. To identify nonideal flows, dynamic tests were conducted using the frequency-modulated random binary input of a brine solution with the feed. The mixing quality in the vessel was substantially improved by increasing the impeller diameter, increasing the residence time, optimizing the impeller off-bottom clearance, decreasing the fluid height, optimizing the jet velocity, and using the up-pumping axial-flow impeller. Applying these findings will lead to improved quality of products and more efficient use of power in continuous-flow mixing of yield-pseudoplastic fluids. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102388y

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Evaluation of group-contribution methods to predict VLE and odor intensity of fragrances / Miguel A. Teixeira in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9390-9402 Titre : Evaluation of group-contribution methods to predict VLE and odor intensity of fragrances Type de document : texte imprimé Auteurs : Miguel A. Teixeira, Auteur ; Oscar Rodriguez, Auteur ; Fatima L. Mota, Auteur Année de publication : 2011 Article en page(s) : pp. 9390-9402 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Odor Group contribution method Résumé : Several predictive GE methods based on the group-contribution concept have been tested for prediction of multicomponent vapor-liquid equilibria (VLE) of fragrance mixtures. The evaluation covered 24 binary, 20 ternary, and 21 quaternary mixtures combining six different fragrances typically used in perfume formulation and ethanol as the solvent. The selected predictive methods are the original UNIFAC (updated to the last revision), the UNIFAC-Dortmund, the ASOG, and the A-UNIFAC. The equilibrium compositions were experimentally measured at 23 °C by headspace gas chromatography (HS-GC). For each liquid composition, the corresponding experimental and predicted vapor compositions were compared. This study confirmed that the UNIFAC method is the best predictive model for prediction of VLE, while the A-UNIFAC performed poorer than other evaluated methods for the mixtures studied in this work. Moreover, from the vapor composition the odor intensity and character of the fragrance mixtures was calculated using a previous developed model which considers the Stevens' power law for the olfaction intensity scale and the stronger component model for quality perception. In this way, the odor intensity and character of fragrance mixtures was predicted and compared to experimental and sensorial evaluations. From this work it can be concluded that the UNIFAC and UNIFAC-Dortmund methods allow obtaining optimal predictions of the character of the fragrance mixtures with an agreement of 95.4% when compared to experimental measurements. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395884 [article] Evaluation of group-contribution methods to predict VLE and odor intensity of fragrances [texte imprimé] / Miguel A. Teixeira, Auteur ; Oscar Rodriguez, Auteur ; Fatima L. Mota, Auteur . - 2011 . - pp. 9390-9402. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9390-9402 Mots-clés : Odor Group contribution method Résumé : Several predictive GE methods based on the group-contribution concept have been tested for prediction of multicomponent vapor-liquid equilibria (VLE) of fragrance mixtures. The evaluation covered 24 binary, 20 ternary, and 21 quaternary mixtures combining six different fragrances typically used in perfume formulation and ethanol as the solvent. The selected predictive methods are the original UNIFAC (updated to the last revision), the UNIFAC-Dortmund, the ASOG, and the A-UNIFAC. The equilibrium compositions were experimentally measured at 23 °C by headspace gas chromatography (HS-GC). For each liquid composition, the corresponding experimental and predicted vapor compositions were compared. This study confirmed that the UNIFAC method is the best predictive model for prediction of VLE, while the A-UNIFAC performed poorer than other evaluated methods for the mixtures studied in this work. Moreover, from the vapor composition the odor intensity and character of the fragrance mixtures was calculated using a previous developed model which considers the Stevens' power law for the olfaction intensity scale and the stronger component model for quality perception. In this way, the odor intensity and character of fragrance mixtures was predicted and compared to experimental and sensorial evaluations. From this work it can be concluded that the UNIFAC and UNIFAC-Dortmund methods allow obtaining optimal predictions of the character of the fragrance mixtures with an agreement of 95.4% when compared to experimental measurements. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395884

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Mixed-convection flow of nanofluids and regular fluids in vertical porous media with viscous heating / Mohammad Memari in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9403-9414 Titre : Mixed-convection flow of nanofluids and regular fluids in vertical porous media with viscous heating Type de document : texte imprimé Auteurs : Mohammad Memari, Auteur ; Ayub Golmakani, Auteur ; Asghar Molaei Dehkordi, Auteur Année de publication : 2011 Article en page(s) : pp. 9403-9414 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Heating Porous medium Convection flow Résumé : In this article, the problem of combined forced and natural convection in a vertical porous channel for both regular fluids and nanofluids has been solved by perturbation and numerical methods, taking into account the influences of viscous heating and inertial force. In this regard, various types of viscous dissipation models, including the Darcy model, the power of drag force model, and the clear fluid compatible model, were considered to account for viscous heating. In addition, the mass flux of nanoparticles was also considered in terms of Brownian and thermophoresis mechanisms. The velocity and temperature distributions of both the regular fluid and nanofluid and the Nusselt number values were determined by considering isothermal boundary conditions in terms of Grashof, Reynolds, Forchheimer, Brinkman, and Darcy numbers. Moreover, the results of the numerical method were validated against those predicted by the perturbation method for small values of the Forchheimer drag term and the Brinkman number. In addition, the results obtained for both the nanofluid and the regular fluid were compared in terms of dimensionless parameters such as Brinkman number, Forchheimer drag term, pressure drop, Grashof-to-Reynolds-number ratio, Darcy number, and nanoparticle mass flux. The predicted results clearly indicate that the presence of nanoparticles enhances the Nusselt number values significantly. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395885 [article] Mixed-convection flow of nanofluids and regular fluids in vertical porous media with viscous heating [texte imprimé] / Mohammad Memari, Auteur ; Ayub Golmakani, Auteur ; Asghar Molaei Dehkordi, Auteur . - 2011 . - pp. 9403-9414. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9403-9414 Mots-clés : Heating Porous medium Convection flow Résumé : In this article, the problem of combined forced and natural convection in a vertical porous channel for both regular fluids and nanofluids has been solved by perturbation and numerical methods, taking into account the influences of viscous heating and inertial force. In this regard, various types of viscous dissipation models, including the Darcy model, the power of drag force model, and the clear fluid compatible model, were considered to account for viscous heating. In addition, the mass flux of nanoparticles was also considered in terms of Brownian and thermophoresis mechanisms. The velocity and temperature distributions of both the regular fluid and nanofluid and the Nusselt number values were determined by considering isothermal boundary conditions in terms of Grashof, Reynolds, Forchheimer, Brinkman, and Darcy numbers. Moreover, the results of the numerical method were validated against those predicted by the perturbation method for small values of the Forchheimer drag term and the Brinkman number. In addition, the results obtained for both the nanofluid and the regular fluid were compared in terms of dimensionless parameters such as Brinkman number, Forchheimer drag term, pressure drop, Grashof-to-Reynolds-number ratio, Darcy number, and nanoparticle mass flux. The predicted results clearly indicate that the presence of nanoparticles enhances the Nusselt number values significantly. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395885

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Influence of nonbasic nitrogen compounds and condensed aromatics on coker gas oil catalytic cracking and their characterization / Ze-kun Li in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp 9415–9424 Titre : Influence of nonbasic nitrogen compounds and condensed aromatics on coker gas oil catalytic cracking and their characterization Type de document : texte imprimé Auteurs : Ze-kun Li, Auteur ; Jin-sen Gao, Auteur ; Gang Wang, Auteur Année de publication : 2011 Article en page(s) : pp 9415–9424 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nonbasic nitrogen compounds Coker gas oil catalytic Résumé : Contrastive fluid catalytic cracking (FCC) performances of coker gas oil (CGO) narrow-boiling fractions before and after HCl aqueous solution and furfural further treatment were investigated. Nonbasic nitrogen compounds and condensed aromatics in test oil samples were identified by negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) and gas chromatography and mass spectrometry (GC–MS), respectively. The results show that basic nitrogen compounds mainly retard the feed conversion and liquid products due to their interaction with Brønsted acid sites or Lewis acid sites during catalytic cracking reactions, while the nonbasic nitrogen compounds and condensed aromatics are hard to convert into smaller molecules, just resulting in obvious effects on yields of gasoline and diesel. Moreover, nonbasic nitrogen compounds with single N species are dominant in CGO, identified as carbazoles, cycloalkyl-carbazoles, benzocarbazoles, and cycloalkyl-benzocarbazoles. Condensed aromatics include three to four rings of large dynamic size, usually presented as chrysene, pyrene, and phenanthrene. These compounds deposit on the surface of catalysts and thus redundant coke is formed; consequently, entrances for other hydrocarbons into acid centers are jammed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2003973 [article] Influence of nonbasic nitrogen compounds and condensed aromatics on coker gas oil catalytic cracking and their characterization [texte imprimé] / Ze-kun Li, Auteur ; Jin-sen Gao, Auteur ; Gang Wang, Auteur . - 2011 . - pp 9415–9424. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp 9415–9424 Mots-clés : Nonbasic nitrogen compounds Coker gas oil catalytic Résumé : Contrastive fluid catalytic cracking (FCC) performances of coker gas oil (CGO) narrow-boiling fractions before and after HCl aqueous solution and furfural further treatment were investigated. Nonbasic nitrogen compounds and condensed aromatics in test oil samples were identified by negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) and gas chromatography and mass spectrometry (GC–MS), respectively. The results show that basic nitrogen compounds mainly retard the feed conversion and liquid products due to their interaction with Brønsted acid sites or Lewis acid sites during catalytic cracking reactions, while the nonbasic nitrogen compounds and condensed aromatics are hard to convert into smaller molecules, just resulting in obvious effects on yields of gasoline and diesel. Moreover, nonbasic nitrogen compounds with single N species are dominant in CGO, identified as carbazoles, cycloalkyl-carbazoles, benzocarbazoles, and cycloalkyl-benzocarbazoles. Condensed aromatics include three to four rings of large dynamic size, usually presented as chrysene, pyrene, and phenanthrene. These compounds deposit on the surface of catalysts and thus redundant coke is formed; consequently, entrances for other hydrocarbons into acid centers are jammed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2003973

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Effect of n-butanol blending with a blend of diesel and biodiesel on performance and exhaust emissions of a diesel engine / Şehmus Altun in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9425-9430 Titre : Effect of n-butanol blending with a blend of diesel and biodiesel on performance and exhaust emissions of a diesel engine Type de document : texte imprimé Auteurs : Şehmus Altun, Auteur ; Cengiz Oner, Auteur ; Fevzi Yaşar, Auteur Année de publication : 2011 Article en page(s) : pp. 9425-9430 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Diesel engine Résumé : Experimental work was conducted to evaluate the effect of using n-butanol (normal butanol) in conventional diesel fuel-biodiesel blends on the engine performance and exhaust emissions of a single cylinder direct injection compression ignition engine with the engine working at a constant engine speed and at different three engine loads. A blend ofbiodiesel and diesel fuel known as B20 (20% biodiesel and 80% diesel in volume) was prepared, and then n-butanol was added to B20 at a volume percent of 10% and 20% (denoted as B20Bu10 and B20Bu20, respectively). Fuel consumption; regulated exhaust emissions such as nitrogen oxides, carbon monoxide, and total unburned hydrocarbons; and smoke opacity were measured. The brake specific fuel consumption of fuel blends was found to be higher when compared to that of conventional diesel fuel On the other hand, the addition of n-butanol to the B20 fuel blend caused a slight increase in the brake specific fuel consumption and brake thermal efficiency in comparison to the B20 fuel blend. For exhaust emissions, carbon monoxide (CO) and hydrocarbon (HCs) emissions decreased, and NOx remained almost unchanged at low engine loads, while it decreased at high engine loads. Fuel blends also resulted in a sharp reduction of smoke opacity in the whole range of engine tests. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395887 [article] Effect of n-butanol blending with a blend of diesel and biodiesel on performance and exhaust emissions of a diesel engine [texte imprimé] / Şehmus Altun, Auteur ; Cengiz Oner, Auteur ; Fevzi Yaşar, Auteur . - 2011 . - pp. 9425-9430. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9425-9430 Mots-clés : Diesel engine Résumé : Experimental work was conducted to evaluate the effect of using n-butanol (normal butanol) in conventional diesel fuel-biodiesel blends on the engine performance and exhaust emissions of a single cylinder direct injection compression ignition engine with the engine working at a constant engine speed and at different three engine loads. A blend ofbiodiesel and diesel fuel known as B20 (20% biodiesel and 80% diesel in volume) was prepared, and then n-butanol was added to B20 at a volume percent of 10% and 20% (denoted as B20Bu10 and B20Bu20, respectively). Fuel consumption; regulated exhaust emissions such as nitrogen oxides, carbon monoxide, and total unburned hydrocarbons; and smoke opacity were measured. The brake specific fuel consumption of fuel blends was found to be higher when compared to that of conventional diesel fuel On the other hand, the addition of n-butanol to the B20 fuel blend caused a slight increase in the brake specific fuel consumption and brake thermal efficiency in comparison to the B20 fuel blend. For exhaust emissions, carbon monoxide (CO) and hydrocarbon (HCs) emissions decreased, and NOx remained almost unchanged at low engine loads, while it decreased at high engine loads. Fuel blends also resulted in a sharp reduction of smoke opacity in the whole range of engine tests. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395887

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Pressure drop and residence time distribution in carbon-nanofiber/gaphite-felt composite for single liquid-phase flow / Yaojie Cao in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9431-9436 Titre : Pressure drop and residence time distribution in carbon-nanofiber/gaphite-felt composite for single liquid-phase flow Type de document : texte imprimé Auteurs : Yaojie Cao, Auteur ; Ping Li, Auteur ; Jinghong Zhou, Auteur Année de publication : 2011 Article en page(s) : pp. 9431-9436 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Liquid phase Composite material Residence time distribution Hydrodynamics Pressure drop Résumé : Fibrous carbon nanofiber composite is prepared by growing carbon nanofibers on graphite felt Pressure drop experiments are carried out with ethanol solution to study the influence of the liquid surface tension on the permeability of the composite, and residence time distribution experiments with cyclohexane and water respectively are performed to study the effect of the fluid wettability on the flow behavior in the composite. Piston dispersion exchange (PDE) model is employed to determine the dynamic liquid holdup, the axial dispersion, and the mass transfer between the dynamic and static liquids. When the fluid is less oleophilic, less space in the CNF layer will be open for the flow, and the fluid will be more likely to slip over the carbon surface. Compared with the flow in spherical particle packing and in monolith, the mass transfer in the composite is high owing to its fibrous structure that splits the fluid into streamlets. The rate of mass transfer in water is lower than that in cyclohexane because water is only trapped in some of the large pores in the CNF layer while cyclohexane suffuses the whole layer. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395888 [article] Pressure drop and residence time distribution in carbon-nanofiber/gaphite-felt composite for single liquid-phase flow [texte imprimé] / Yaojie Cao, Auteur ; Ping Li, Auteur ; Jinghong Zhou, Auteur . - 2011 . - pp. 9431-9436. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9431-9436 Mots-clés : Liquid phase Composite material Residence time distribution Hydrodynamics Pressure drop Résumé : Fibrous carbon nanofiber composite is prepared by growing carbon nanofibers on graphite felt Pressure drop experiments are carried out with ethanol solution to study the influence of the liquid surface tension on the permeability of the composite, and residence time distribution experiments with cyclohexane and water respectively are performed to study the effect of the fluid wettability on the flow behavior in the composite. Piston dispersion exchange (PDE) model is employed to determine the dynamic liquid holdup, the axial dispersion, and the mass transfer between the dynamic and static liquids. When the fluid is less oleophilic, less space in the CNF layer will be open for the flow, and the fluid will be more likely to slip over the carbon surface. Compared with the flow in spherical particle packing and in monolith, the mass transfer in the composite is high owing to its fibrous structure that splits the fluid into streamlets. The rate of mass transfer in water is lower than that in cyclohexane because water is only trapped in some of the large pores in the CNF layer while cyclohexane suffuses the whole layer. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395888

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Thermodynamic model for the prediction of equilibrium conditions of clathrate hydrates of methane + water-soluble or -insoluble hydrate former / Mohammad Illbeigi in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9437–9450 Titre : Thermodynamic model for the prediction of equilibrium conditions of clathrate hydrates of methane + water-soluble or -insoluble hydrate former Type de document : texte imprimé Auteurs : Mohammad Illbeigi, Auteur ; Alireza Fazlali, Auteur ; Amir H. Mohammadi, Auteur Année de publication : 2011 Article en page(s) : pp. 9437–9450 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Thermodynamic Hydrates of methane Résumé : In this communication, equilibrium conditions of clathrate hydrates of cyclopentane, cylcohexane, acetone, or 1,4-dioxane + methane, which form structure II, and 1,1-dimethylcyclohexane, 2,2-dimethylpentane, methylcyclohexane, or cis-1,2-dimethylcyclohexane + methane, which form structure H, are modeled. The thermodynamic model is based on the van der Waals–Platteeuw solid solution theory combined with an equation of state and activity model. The Peng–Robinson (PR) and Soave–Redlich–Kwong (SRK) equations of state with random mixing rules are used to model the gas phase, while the UNIFAC method is used to model the liquid phase(s). It is shown that the use of the PR equation of state leads to better predictions of hydrate equilibrium conditions of the aforementioned water-insoluble heavy hydrocarbons, while the use of the SRK equation of state causes better predictions of hydrate equilibrium conditions of the latter water-soluble hydrate formers. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200442h [article] Thermodynamic model for the prediction of equilibrium conditions of clathrate hydrates of methane + water-soluble or -insoluble hydrate former [texte imprimé] / Mohammad Illbeigi, Auteur ; Alireza Fazlali, Auteur ; Amir H. Mohammadi, Auteur . - 2011 . - pp. 9437–9450. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9437–9450 Mots-clés : Thermodynamic Hydrates of methane Résumé : In this communication, equilibrium conditions of clathrate hydrates of cyclopentane, cylcohexane, acetone, or 1,4-dioxane + methane, which form structure II, and 1,1-dimethylcyclohexane, 2,2-dimethylpentane, methylcyclohexane, or cis-1,2-dimethylcyclohexane + methane, which form structure H, are modeled. The thermodynamic model is based on the van der Waals–Platteeuw solid solution theory combined with an equation of state and activity model. The Peng–Robinson (PR) and Soave–Redlich–Kwong (SRK) equations of state with random mixing rules are used to model the gas phase, while the UNIFAC method is used to model the liquid phase(s). It is shown that the use of the PR equation of state leads to better predictions of hydrate equilibrium conditions of the aforementioned water-insoluble heavy hydrocarbons, while the use of the SRK equation of state causes better predictions of hydrate equilibrium conditions of the latter water-soluble hydrate formers. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200442h

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Influence of temperature on the rheological behavior of polymer mixtures in solution / Simona Morariu in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9451–9455 Titre : Influence of temperature on the rheological behavior of polymer mixtures in solution Type de document : texte imprimé Auteurs : Simona Morariu, Auteur ; Cristina-Eliza Brunchi, Auteur ; Camelia Hulubei, Auteur Année de publication : 2011 Article en page(s) : pp. 9451–9455 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Rheological behavior of polymer Résumé : This article investigates the viscoelastic behavior of poly(acrylonitrile) (PAN) and poly[N-(4-carboxyphenyl)maleimide] (PMI) solutions in dimethylformamide (DMF) in comparison with PMI/PAN/DMF ternary mixtures. Some rheological characteristics, such as viscosity and relaxation time, were investigated as functions of the polymer mixture composition at different temperatures in the range of 0–60 °C. The solutions of each polymer and their mixtures exhibit a Newtonian behavior throughout the studied frequency range. At low temperatures, the behavior of the solutions having high PAN contents in the polymer mixture is influenced by physical gelation of the solution. The activation energy of the flow gives indications about the intensity of polymer–polymer interactions as a function of the polymer mixture composition. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200736e [article] Influence of temperature on the rheological behavior of polymer mixtures in solution [texte imprimé] / Simona Morariu, Auteur ; Cristina-Eliza Brunchi, Auteur ; Camelia Hulubei, Auteur . - 2011 . - pp. 9451–9455. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9451–9455 Mots-clés : Rheological behavior of polymer Résumé : This article investigates the viscoelastic behavior of poly(acrylonitrile) (PAN) and poly[N-(4-carboxyphenyl)maleimide] (PMI) solutions in dimethylformamide (DMF) in comparison with PMI/PAN/DMF ternary mixtures. Some rheological characteristics, such as viscosity and relaxation time, were investigated as functions of the polymer mixture composition at different temperatures in the range of 0–60 °C. The solutions of each polymer and their mixtures exhibit a Newtonian behavior throughout the studied frequency range. At low temperatures, the behavior of the solutions having high PAN contents in the polymer mixture is influenced by physical gelation of the solution. The activation energy of the flow gives indications about the intensity of polymer–polymer interactions as a function of the polymer mixture composition. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200736e

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On the critical points of thermally cracked hydrocarbon fuels under high pressure / Rongpei Jiang in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9456-9465 Titre : On the critical points of thermally cracked hydrocarbon fuels under high pressure Type de document : texte imprimé Auteurs : Rongpei Jiang, Auteur ; Guozhu Liu, Auteur ; Zhiqiang You, Auteur Année de publication : 2011 Article en page(s) : pp. 9456-9465 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Fuel Crack Critical point Résumé : Thermal cracking of a series of model compounds (n-octane, n-decane, n-dodecane, cydohexane, methylcyclohexane), as well as a commercial Chinese jet fuel RP-3, was performed in a flowing reactor consisting of an electrically heated tube under a pressure of 5 MPa to obtain the chemical compositions of the cracked hydrocarbon fuels at different levels of cracking conversion. The phase envelopes and critical points of the cracked hydrocarbon fuels were calculated using the Peng-Robinson and Soave-Redlich-Kwong equations. The calculation results showed that the critical points for cracked hydrocarbon fuels are strongly dependent on the hydrocarbon type and cracking conversion and that the critical temperature of cracked fuel decreases but the critical pressure increases sharply from 2—4 to above 10 MPa because of the appearance of many small-molecule products. Therefore, phase changes of the hydrocarbon fuel from compressed liquid phase to supercritical phase and then to gas phase possibly occurred in the electrically heated tube reactor when the cracking conversions exceeded 30%. Based on the calculation results, the supercritical cracking of hydrocarbon fuels should be carefully used at higher cracking conversions of hydrocarbon fuels under high pressure. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395891 [article] On the critical points of thermally cracked hydrocarbon fuels under high pressure [texte imprimé] / Rongpei Jiang, Auteur ; Guozhu Liu, Auteur ; Zhiqiang You, Auteur . - 2011 . - pp. 9456-9465. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9456-9465 Mots-clés : Fuel Crack Critical point Résumé : Thermal cracking of a series of model compounds (n-octane, n-decane, n-dodecane, cydohexane, methylcyclohexane), as well as a commercial Chinese jet fuel RP-3, was performed in a flowing reactor consisting of an electrically heated tube under a pressure of 5 MPa to obtain the chemical compositions of the cracked hydrocarbon fuels at different levels of cracking conversion. The phase envelopes and critical points of the cracked hydrocarbon fuels were calculated using the Peng-Robinson and Soave-Redlich-Kwong equations. The calculation results showed that the critical points for cracked hydrocarbon fuels are strongly dependent on the hydrocarbon type and cracking conversion and that the critical temperature of cracked fuel decreases but the critical pressure increases sharply from 2—4 to above 10 MPa because of the appearance of many small-molecule products. Therefore, phase changes of the hydrocarbon fuel from compressed liquid phase to supercritical phase and then to gas phase possibly occurred in the electrically heated tube reactor when the cracking conversions exceeded 30%. Based on the calculation results, the supercritical cracking of hydrocarbon fuels should be carefully used at higher cracking conversions of hydrocarbon fuels under high pressure. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395891

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Hydrogen generation by pulsed gliding arc discharge plasma with sprays of alcohol solutions / Radu Burlica in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9466-9470 Titre : Hydrogen generation by pulsed gliding arc discharge plasma with sprays of alcohol solutions Type de document : texte imprimé Auteurs : Radu Burlica, Auteur ; Kai-Yuan Shih, Auteur ; Bogdan Hnatiuc, Auteur Année de publication : 2011 Article en page(s) : pp. 9466-9470 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Alcoholic solution Plasma Hydrogen production Résumé : The formation rates and energy yields of H2 formed from methanol, propanol, and ethanol solutions exposed to a nonthermal pulsed plasma-gliding arc reactor equipped with a spray nozzle were determined. The H2 energy yield formation was the highest with Ar carrier and pure methanol giving 176 ± 25% kW h at the highest liquid flow rate. This value is higher than other reported plasma technologies and within error of the energy yields for more conventional thermal reforming. Liquid droplets can enhance energy yield; however, the low chemical yields of H2 suggest the need for reactor operation with a recycle stream. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395892 [article] Hydrogen generation by pulsed gliding arc discharge plasma with sprays of alcohol solutions [texte imprimé] / Radu Burlica, Auteur ; Kai-Yuan Shih, Auteur ; Bogdan Hnatiuc, Auteur . - 2011 . - pp. 9466-9470. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9466-9470 Mots-clés : Alcoholic solution Plasma Hydrogen production Résumé : The formation rates and energy yields of H2 formed from methanol, propanol, and ethanol solutions exposed to a nonthermal pulsed plasma-gliding arc reactor equipped with a spray nozzle were determined. The H2 energy yield formation was the highest with Ar carrier and pure methanol giving 176 ± 25% kW h at the highest liquid flow rate. This value is higher than other reported plasma technologies and within error of the energy yields for more conventional thermal reforming. Liquid droplets can enhance energy yield; however, the low chemical yields of H2 suggest the need for reactor operation with a recycle stream. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395892

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