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Vol. 50 N° 6 - Mars 2011 [texte imprimé] . - 2011 . - p. 3071-3632 : ill. ; 28 cm. Chemical engineering Langues : Anglais (eng)
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Ajouter le résultat dans votre panierPhysicochemical properties of oil-based nanofluids containing hybrid structures of silver nanoparticles supported on silica / Subelia S. Botha in Industrial & engineering chemistry research, Vol. 50 N° 6 (Mars 2011)
Titre : Physicochemical properties of oil-based nanofluids containing hybrid structures of silver nanoparticles supported on silica Type de document : texte imprimé Auteurs : Subelia S. Botha, Auteur ; Patrick Ndungu, Auteur ; Bernard J. Bladergroen, Auteur Année de publication : 2011 Article en page(s) : pp. 3071-3077 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nanoparticle Physicochemical properties Résumé : The structural, rheological, thermal, and dielectric properties of transformer oil-based nanofluids containing silica and silver supported on silica were investigated. Thermal conductivity was found to increase with silica concentration. The greatest enhancement was seen with silver nanoparticles supported on silica at very low weight percent of silica. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944472
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3071-3077[article] Physicochemical properties of oil-based nanofluids containing hybrid structures of silver nanoparticles supported on silica [texte imprimé] / Subelia S. Botha, Auteur ; Patrick Ndungu, Auteur ; Bernard J. Bladergroen, Auteur . - 2011 . - pp. 3071-3077.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3071-3077
Mots-clés : Nanoparticle Physicochemical properties Résumé : The structural, rheological, thermal, and dielectric properties of transformer oil-based nanofluids containing silica and silver supported on silica were investigated. Thermal conductivity was found to increase with silica concentration. The greatest enhancement was seen with silver nanoparticles supported on silica at very low weight percent of silica. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944472 Exemplaires
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Titre : Influence of energetic heterogeneity and lateral interactions between adsorbed molecules on the kinetics of gas adsorption Type de document : texte imprimé Auteurs : Krzystof Nieszporek, Auteur ; Tomasz Banach, Auteur Année de publication : 2011 Article en page(s) : pp. 3078-3088 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Adsorption Kinetics Heterogeneity Résumé : The kinetics of pure gas adsorption on energetically heterogeneous solid surfaces has been studied by statistical rate theory. The theoretical investigations take into account the influence of lateral interactions between adsorbed molecules. The energetic heterogeneity of the adsorption system has been described by the rectangular energy distribution function. The obtained kinetic expression is based on the exact solution of the integral equation approach. The experimental systems of alkane adsorption on activated carbons were used for quantitative analysis. As a result, a good simultaneous description of equilibria and kinetics in these systems was obtained. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944473
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3078-3088[article] Influence of energetic heterogeneity and lateral interactions between adsorbed molecules on the kinetics of gas adsorption [texte imprimé] / Krzystof Nieszporek, Auteur ; Tomasz Banach, Auteur . - 2011 . - pp. 3078-3088.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3078-3088
Mots-clés : Adsorption Kinetics Heterogeneity Résumé : The kinetics of pure gas adsorption on energetically heterogeneous solid surfaces has been studied by statistical rate theory. The theoretical investigations take into account the influence of lateral interactions between adsorbed molecules. The energetic heterogeneity of the adsorption system has been described by the rectangular energy distribution function. The obtained kinetic expression is based on the exact solution of the integral equation approach. The experimental systems of alkane adsorption on activated carbons were used for quantitative analysis. As a result, a good simultaneous description of equilibria and kinetics in these systems was obtained. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944473 Exemplaires
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Titre : A facile method to prepare superhydrophobic coatings by calcium carbonate Type de document : texte imprimé Auteurs : Hua Zhang, Auteur ; Xiaofei Zeng, Auteur ; Yongfeng Gao, Auteur Année de publication : 2011 Article en page(s) : pp. 3089–3094 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Calcium Carbonate Résumé : In this work, we have developed a facile and inexpensive method to fabricate a superhydrophobic surface with hierarchical nano- and microstructures. The superhydrophobic surface was prepared through spin coating of a mixture of nano- and microsized calcium carbonate (CaCO3) suspensions on a substrate, followed by modification of a low-surface-energy monolayer of stearic acid. The key parameters of the fabrication of suitable surface morphologies, including the content of CaCO3 powder and the percentage of nano- and microsized CaCO3 powder, were also investigated. Results showed that the optimum CaCO3 content was 40 wt % and the self-cleaning property of the film was achieved only by the addition of 2 wt % microsized CaCO3 powder and 38 wt % nanosized CaCO3 powder. After modification with a self-assembled monolayer of stearic acid, the as-prepared coating showed self-cleaning properties with a water contact angle as high as 152.8° and a sliding angle of 7.8°. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102149y
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3089–3094[article] A facile method to prepare superhydrophobic coatings by calcium carbonate [texte imprimé] / Hua Zhang, Auteur ; Xiaofei Zeng, Auteur ; Yongfeng Gao, Auteur . - 2011 . - pp. 3089–3094.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3089–3094
Mots-clés : Calcium Carbonate Résumé : In this work, we have developed a facile and inexpensive method to fabricate a superhydrophobic surface with hierarchical nano- and microstructures. The superhydrophobic surface was prepared through spin coating of a mixture of nano- and microsized calcium carbonate (CaCO3) suspensions on a substrate, followed by modification of a low-surface-energy monolayer of stearic acid. The key parameters of the fabrication of suitable surface morphologies, including the content of CaCO3 powder and the percentage of nano- and microsized CaCO3 powder, were also investigated. Results showed that the optimum CaCO3 content was 40 wt % and the self-cleaning property of the film was achieved only by the addition of 2 wt % microsized CaCO3 powder and 38 wt % nanosized CaCO3 powder. After modification with a self-assembled monolayer of stearic acid, the as-prepared coating showed self-cleaning properties with a water contact angle as high as 152.8° and a sliding angle of 7.8°. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102149y Exemplaires
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Titre : Nanoassembly of block copolymer micelle and graphene oxide to multilayer coatings Type de document : texte imprimé Auteurs : Jinkee Hong, Auteur ; Yong Soo Kang, Auteur ; Sang Wook Kang, Auteur Année de publication : 2011 Article en page(s) : pp. 3095–3099 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Copolymer Oxide Résumé : We report on the preparation and characterization of multidimensional nano-objects nanoassembly in film surface coatings. 2D reduced graphene oxide (rGO) sheets are assembled with 0D block copolymer micelles (BCM)s through electrostatic layer-by-layer assembly. The BCM/rGO paired nanoassembly surface coatings were formed via sequential adsorption of polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) aqueous solutionsand modified rGO sheets with carboxylic acids groups, and the process was monitored by UV−vis spectroscopy. SEM and AFM were used to investigate surface morphology and the growth of multilayer coatings as a function of the number of bilayers. In addition, encapsulated hydrophobic fluorescence organic dyes were imaged via confocal microscopy. Evenly distributed BCMs on coatings were successfully obtained. We expect that this demonstration offers a new route to introduce nanoassembly of two different dimensional-shaped nano-objects in surface coatings for many industrial uses and makes building more complex, functional multicomponent, and multidimensional structures possible for use in nano-objects incorporated various multicoating applications. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1022282
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3095–3099[article] Nanoassembly of block copolymer micelle and graphene oxide to multilayer coatings [texte imprimé] / Jinkee Hong, Auteur ; Yong Soo Kang, Auteur ; Sang Wook Kang, Auteur . - 2011 . - pp. 3095–3099.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3095–3099
Mots-clés : Copolymer Oxide Résumé : We report on the preparation and characterization of multidimensional nano-objects nanoassembly in film surface coatings. 2D reduced graphene oxide (rGO) sheets are assembled with 0D block copolymer micelles (BCM)s through electrostatic layer-by-layer assembly. The BCM/rGO paired nanoassembly surface coatings were formed via sequential adsorption of polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) aqueous solutionsand modified rGO sheets with carboxylic acids groups, and the process was monitored by UV−vis spectroscopy. SEM and AFM were used to investigate surface morphology and the growth of multilayer coatings as a function of the number of bilayers. In addition, encapsulated hydrophobic fluorescence organic dyes were imaged via confocal microscopy. Evenly distributed BCMs on coatings were successfully obtained. We expect that this demonstration offers a new route to introduce nanoassembly of two different dimensional-shaped nano-objects in surface coatings for many industrial uses and makes building more complex, functional multicomponent, and multidimensional structures possible for use in nano-objects incorporated various multicoating applications. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1022282 Exemplaires
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Titre : Numerical integration of the chemical rate equations via a discretized adomian decomposition Type de document : texte imprimé Auteurs : Jarod M. Younker, Auteur Année de publication : 2011 Article en page(s) : pp. 3100–3109 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Adomian decomposition methods Résumé : Chemists are frequently interested in rate equations, which are first-order differential equations. Numerical integration of these equations allows the researcher to accurately predict the concentrations of chemical species at any time given the initial conditions. Explicit Runge−Kutta (RK) integration is widely used for solving the rate equations. In this article, Adomian decomposition methods (ADM) are used to obtain the solutions of chemical rate equations. The Adomian method outlined here outperforms high-order RK routines in the arenas of accuracy and truncation error. Additionally, four modifications are introduced that place the Adomian integration on par with RK in terms of speed (a primary reason for which Adomian decomposition methods are currently underemployed). The inclusion of up to the fifth term in the Adomian expansion gives a truncation error of order O(h10). The method as presented yields solutions which are step-size independent in the nonstiff regime. The problem of rapid polynomial divergence is addressed through discretizing the time axis. Performance of the ADM method against an implicit algorithm is also given. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1008647
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3100–3109[article] Numerical integration of the chemical rate equations via a discretized adomian decomposition [texte imprimé] / Jarod M. Younker, Auteur . - 2011 . - pp. 3100–3109.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3100–3109
Mots-clés : Adomian decomposition methods Résumé : Chemists are frequently interested in rate equations, which are first-order differential equations. Numerical integration of these equations allows the researcher to accurately predict the concentrations of chemical species at any time given the initial conditions. Explicit Runge−Kutta (RK) integration is widely used for solving the rate equations. In this article, Adomian decomposition methods (ADM) are used to obtain the solutions of chemical rate equations. The Adomian method outlined here outperforms high-order RK routines in the arenas of accuracy and truncation error. Additionally, four modifications are introduced that place the Adomian integration on par with RK in terms of speed (a primary reason for which Adomian decomposition methods are currently underemployed). The inclusion of up to the fifth term in the Adomian expansion gives a truncation error of order O(h10). The method as presented yields solutions which are step-size independent in the nonstiff regime. The problem of rapid polynomial divergence is addressed through discretizing the time axis. Performance of the ADM method against an implicit algorithm is also given. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1008647 Exemplaires
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Titre : Modeling of a fluidized bed membrane reactor for hydrogen production by steam reforming of hydrocarbons Type de document : texte imprimé Auteurs : Mohammad A. Rakib, Auteur ; John R. Grace, Auteur ; C. Jim Lim, Auteur Année de publication : 2011 Article en page(s) : pp. 3110–3129 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Membrane reactor Hydrogen production Résumé : A bubbling fluidized bed membrane reactor (FBMR) is modeled to estimate and predict the steam reforming of hydrocarbons. A two-phase fluidization model is used, with both the bubble and dense phases in plug flow. Diffusional mass transfer, as well as bulk convective mass flow between the phases, is incorporated to account for reactions occurring predominantly in the dense phase and increases in molar flow due to the reaction. Steam reforming of higher hydrocarbons is limited by the thermodynamic equilibrium of the methane steam reforming and water−gas shift reactions. The model predicts flexible feedstock capabilities, showing that most of the reactor does not actually see the higher hydrocarbon feed. With a single fitted constant to account for membrane effectiveness in the fluidized bed relative to that in the absence of particles, good agreement is obtained between model predictions and reactor performance of the reforming of methane, propane, and heptane. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100954a
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3110–3129[article] Modeling of a fluidized bed membrane reactor for hydrogen production by steam reforming of hydrocarbons [texte imprimé] / Mohammad A. Rakib, Auteur ; John R. Grace, Auteur ; C. Jim Lim, Auteur . - 2011 . - pp. 3110–3129.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3110–3129
Mots-clés : Membrane reactor Hydrogen production Résumé : A bubbling fluidized bed membrane reactor (FBMR) is modeled to estimate and predict the steam reforming of hydrocarbons. A two-phase fluidization model is used, with both the bubble and dense phases in plug flow. Diffusional mass transfer, as well as bulk convective mass flow between the phases, is incorporated to account for reactions occurring predominantly in the dense phase and increases in molar flow due to the reaction. Steam reforming of higher hydrocarbons is limited by the thermodynamic equilibrium of the methane steam reforming and water−gas shift reactions. The model predicts flexible feedstock capabilities, showing that most of the reactor does not actually see the higher hydrocarbon feed. With a single fitted constant to account for membrane effectiveness in the fluidized bed relative to that in the absence of particles, good agreement is obtained between model predictions and reactor performance of the reforming of methane, propane, and heptane. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100954a Exemplaires
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Titre : Sunlight - induced photocatalytic degradation of organic pollutants by carbon-modified nanotitania with vegetable oil as precursor Type de document : texte imprimé Auteurs : Jeevitha R. Raji, Auteur ; Kandasamy Palanivelu, Auteur Année de publication : 2011 Article en page(s) : pp. 3130–3138 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Photocatalytic Organic pollutants Résumé : An attempt has been made in this study to prepare a nanosized titanium dioxide catalyst by an ultrasonication assisted sol−gel process at low temperature. The as-synthesized titania was modified with carbon from coconut oil as a carbon precursor in two different proportions and then subjected to thermal and microwave treatment. The characterization of the pure and carbon modified titania catalysts was accomplished by XRD, SEM, HR-SEM/EDX, UV−vis absorption spectroscopy, and BET surface area analysis. The average size of the carbon modified TiO2 catalysts was found to be in the range of 90 nm. The solar photocatalytic activity of the catalysts was monitored by the degradation of a cationic dye, methylene blue, and an anionic dye, methyl orange. The effect of pH on the degradation of the dyes was also investigated. The study revealed that the degradation of the cationic dye was highly pronounced in the alkaline pH, whereas, the degradation of the anionic dye was effective in acidic pH. A solar photochemical study was also conducted with 2,4-dichlorophenol to ensure the degradation of visible light nonabsorbing organic compounds. The study revealed that carbon-modified catalysts with about 8.0 wt % of carbon was found to have the highest solar phoactivity, when compared to the pure titania and the carbon modified titania with 42% of carbon. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101259p
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3130–3138[article] Sunlight - induced photocatalytic degradation of organic pollutants by carbon-modified nanotitania with vegetable oil as precursor [texte imprimé] / Jeevitha R. Raji, Auteur ; Kandasamy Palanivelu, Auteur . - 2011 . - pp. 3130–3138.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3130–3138
Mots-clés : Photocatalytic Organic pollutants Résumé : An attempt has been made in this study to prepare a nanosized titanium dioxide catalyst by an ultrasonication assisted sol−gel process at low temperature. The as-synthesized titania was modified with carbon from coconut oil as a carbon precursor in two different proportions and then subjected to thermal and microwave treatment. The characterization of the pure and carbon modified titania catalysts was accomplished by XRD, SEM, HR-SEM/EDX, UV−vis absorption spectroscopy, and BET surface area analysis. The average size of the carbon modified TiO2 catalysts was found to be in the range of 90 nm. The solar photocatalytic activity of the catalysts was monitored by the degradation of a cationic dye, methylene blue, and an anionic dye, methyl orange. The effect of pH on the degradation of the dyes was also investigated. The study revealed that the degradation of the cationic dye was highly pronounced in the alkaline pH, whereas, the degradation of the anionic dye was effective in acidic pH. A solar photochemical study was also conducted with 2,4-dichlorophenol to ensure the degradation of visible light nonabsorbing organic compounds. The study revealed that carbon-modified catalysts with about 8.0 wt % of carbon was found to have the highest solar phoactivity, when compared to the pure titania and the carbon modified titania with 42% of carbon. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101259p Exemplaires
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Titre : Reaction performance of hydrogen from aqueous - phase reforming of methanol or ethanol in hydrogenation of phenol Type de document : texte imprimé Auteurs : Yizhi Xiang, Auteur ; Xiaonian Li, Auteur ; Chunshan Lu, Auteur Année de publication : 2011 Article en page(s) : pp. 3139–3144 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydrogen Methanol Ethanol Résumé : Reaction performances of hydrogen generated from aqueous-phase reforming (APR) of methanol or ethanol were investigated in hydrogenation of phenol, o-cresol and p-tert-butylphenol, over a Raney Ni or Pd/Al2O3 catalyst, respectively. The properties of the adsorbed hydrogen from aqueous-methanol/-ethanol, and H2-gas were studied by means of temperature-programmed surface reaction in liquid phase and temperature-programmed desorption. The results shown that the selectivities of cyclohexanone are 20.5% and 96.1%, 27.4% and 92.4%, and 12.6% and 71.1% in the hydrogenation of phenol with hydrogen from APR of methanol, APR of ethanol, and H2-gas over the Raney Ni and Pd/Al2O3 catalyst, respectively. The limited amount of adsorbed hydrogen from the APR of methanol or ethanol favors the formation of cyclohexanone, but excessive amounts of adsorbed hydrogen from H2-gas favors the formation of cyclohexanol in hydrogenation of phenol. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101411h
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3139–3144[article] Reaction performance of hydrogen from aqueous - phase reforming of methanol or ethanol in hydrogenation of phenol [texte imprimé] / Yizhi Xiang, Auteur ; Xiaonian Li, Auteur ; Chunshan Lu, Auteur . - 2011 . - pp. 3139–3144.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3139–3144
Mots-clés : Hydrogen Methanol Ethanol Résumé : Reaction performances of hydrogen generated from aqueous-phase reforming (APR) of methanol or ethanol were investigated in hydrogenation of phenol, o-cresol and p-tert-butylphenol, over a Raney Ni or Pd/Al2O3 catalyst, respectively. The properties of the adsorbed hydrogen from aqueous-methanol/-ethanol, and H2-gas were studied by means of temperature-programmed surface reaction in liquid phase and temperature-programmed desorption. The results shown that the selectivities of cyclohexanone are 20.5% and 96.1%, 27.4% and 92.4%, and 12.6% and 71.1% in the hydrogenation of phenol with hydrogen from APR of methanol, APR of ethanol, and H2-gas over the Raney Ni and Pd/Al2O3 catalyst, respectively. The limited amount of adsorbed hydrogen from the APR of methanol or ethanol favors the formation of cyclohexanone, but excessive amounts of adsorbed hydrogen from H2-gas favors the formation of cyclohexanol in hydrogenation of phenol. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101411h Exemplaires
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Titre : Systematic procedures for interpretation and modeling of catalyst deactivation using integral fixed-bed reactors Type de document : texte imprimé Auteurs : John J. Birtill, Auteur Année de publication : 2011 Article en page(s) : pp. 3145–3158 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalyst Composition fluid phase Résumé : The method of decreasing conversion, constant space−time (DCCST) is sometimes used for empirical determination of catalyst decay kinetics in fixed beds. The method of constant conversion, increasing space−time (CCIST) is used infrequently. Although it is well known that these methods are most readily applied to cases in which the deactivation is independent of the composition of the fluid phase, the ease with which they can be misapplied to concentration-dependent cases has not been studied systematically. In this work, the empirical determination of catalyst decay kinetics in fixed beds has been examined by numerical simulation. It has been shown that it is rather easy to generate an invalid concentration-independent decay model, either by fitting a dubious straight line to a limited range of data using the DCCST method or by fitting a good, or even perfect, straight line using the CCIST method. It has also been shown that both methods can, in principle, be used reliably for empirical determination of catalyst decay kinetics, whatever the dependence on composition, provided that multiple experiments are carried out over a range of conversion. The CCIST method has much greater potential for resolving reaction and decay kinetics than has been realized previously, and it can be applied to reversible as well as irreversible reactions. This method will generally give a linear plot, provided that the selected plot corresponds to the actual decay order. The plot is exactly linear for any first-order decay kinetics and almost linear for non-first-order decay kinetics. Exact analytical solutions have been derived for various first-order cases. These solutions can be used to determine the true decay kinetics from multiple parallel experiments. Deviation from ideal behavior in this method is a useful indication that the power-law decay kinetics has a limited range of validity, beyond which a more detailed, systematic investigation may be required. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101481y
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3145–3158[article] Systematic procedures for interpretation and modeling of catalyst deactivation using integral fixed-bed reactors [texte imprimé] / John J. Birtill, Auteur . - 2011 . - pp. 3145–3158.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3145–3158
Mots-clés : Catalyst Composition fluid phase Résumé : The method of decreasing conversion, constant space−time (DCCST) is sometimes used for empirical determination of catalyst decay kinetics in fixed beds. The method of constant conversion, increasing space−time (CCIST) is used infrequently. Although it is well known that these methods are most readily applied to cases in which the deactivation is independent of the composition of the fluid phase, the ease with which they can be misapplied to concentration-dependent cases has not been studied systematically. In this work, the empirical determination of catalyst decay kinetics in fixed beds has been examined by numerical simulation. It has been shown that it is rather easy to generate an invalid concentration-independent decay model, either by fitting a dubious straight line to a limited range of data using the DCCST method or by fitting a good, or even perfect, straight line using the CCIST method. It has also been shown that both methods can, in principle, be used reliably for empirical determination of catalyst decay kinetics, whatever the dependence on composition, provided that multiple experiments are carried out over a range of conversion. The CCIST method has much greater potential for resolving reaction and decay kinetics than has been realized previously, and it can be applied to reversible as well as irreversible reactions. This method will generally give a linear plot, provided that the selected plot corresponds to the actual decay order. The plot is exactly linear for any first-order decay kinetics and almost linear for non-first-order decay kinetics. Exact analytical solutions have been derived for various first-order cases. These solutions can be used to determine the true decay kinetics from multiple parallel experiments. Deviation from ideal behavior in this method is a useful indication that the power-law decay kinetics has a limited range of validity, beyond which a more detailed, systematic investigation may be required. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101481y Exemplaires
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Titre : Design of turbulent flame aerosol reactors by mixing-limited fluid dynamics Type de document : texte imprimé Auteurs : Arto J. Grohn, Auteur ; Beat Buesser, Auteur ; Jorma K. Jokiniemi, Auteur Année de publication : 2011 Article en page(s) : pp. 3159–3168 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Turbulent Fluid dynamics Résumé : Nanoparticle synthesis in turbulent flame aerosol reactors is elucidated by computational fluid dynamics (CFD). Mixing-limited combustion is modeled, and total particle number, area, and volume concentration are described by transport equations including terms for particle dynamics. The spread of the particle size distribution at a given streamline is neglected as flame-made aerosols rapidly attain their self-preserving distribution. Results are in good agreement with primary particle data of turbulent diffusion flame synthesis of silica nanoparticles by oxidation of hexamethyldisiloxane vapor at different laboratories without adjustable parameters. Measured agglomerate mobility diameters best matched the predicted volume-equivalent soft-agglomerate diameters. The employed fractal-like dimensions (Df = 1.5−3) had no effect on the predicted primary particle and aggregate diameters and a rather small effect on volume-equivalent soft-agglomerate diameters. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1017817
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3159–3168[article] Design of turbulent flame aerosol reactors by mixing-limited fluid dynamics [texte imprimé] / Arto J. Grohn, Auteur ; Beat Buesser, Auteur ; Jorma K. Jokiniemi, Auteur . - 2011 . - pp. 3159–3168.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3159–3168
Mots-clés : Turbulent Fluid dynamics Résumé : Nanoparticle synthesis in turbulent flame aerosol reactors is elucidated by computational fluid dynamics (CFD). Mixing-limited combustion is modeled, and total particle number, area, and volume concentration are described by transport equations including terms for particle dynamics. The spread of the particle size distribution at a given streamline is neglected as flame-made aerosols rapidly attain their self-preserving distribution. Results are in good agreement with primary particle data of turbulent diffusion flame synthesis of silica nanoparticles by oxidation of hexamethyldisiloxane vapor at different laboratories without adjustable parameters. Measured agglomerate mobility diameters best matched the predicted volume-equivalent soft-agglomerate diameters. The employed fractal-like dimensions (Df = 1.5−3) had no effect on the predicted primary particle and aggregate diameters and a rather small effect on volume-equivalent soft-agglomerate diameters. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1017817 Exemplaires
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Titre : Toluene disproportionation and methylation over zeolites TNU-9, SSZ-33, ZSM-5, and mordenite using different reactor systems Type de document : texte imprimé Auteurs : T. Odedairo, Auteur ; R. J. Balasamy, Auteur ; Al-Khattaf, S., Auteur Année de publication : 2011 Article en page(s) : pp. 3169-3183 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Reactor Zeolite Methylation Disproportionation Résumé : An array of zeolites varying in the channel structural design and acidity was investigated in toluene methylation with methanol, together with toluene disproportionation, using fluidized-bed and fixed-bed reactors. The conversions of toluene in the methylation and disproportionation reactions in the fixed-bed reactor were higher than those in the fluidized-bed reactor over the zeolite based catalysts at similar reaction conditions. The unique pore architecture of zeolite TNU-9, with 10-ring channel systems, being slightly larger zeolite compared with ZSM-5, can offer new opportunities for toluene disproportionation, as well as for toluene methylation. The medium pore zeolite TNU-9 was found to possess the highest conversion in toluene disproportionation as compared with other zeolite based catalysts under study. In toluene methylation, the highest toluene conversion was achieved with mordenite based catalyst (MOR-A), while the xylene selectivity follows the order: ZSM-5 > TNU-9 > MOR-A > SSZ-33 > MOR-B. This order indicates that xylene selectivity is directly related to the size of channels from medium to large pore zeolites. Using the fluidized bed, the apparent activation energies for toluene methylation follow the order: ZSM-5 (46.8 kJ/mol) > TNU-9 (33.9 kJ/mol) > MOR-B (13.9 kJ/mol) ≈ MOR-A (13.1 kJ/mol) > SSZ-33 (8.2 kJ/mol). DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944482
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3169-3183[article] Toluene disproportionation and methylation over zeolites TNU-9, SSZ-33, ZSM-5, and mordenite using different reactor systems [texte imprimé] / T. Odedairo, Auteur ; R. J. Balasamy, Auteur ; Al-Khattaf, S., Auteur . - 2011 . - pp. 3169-3183.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3169-3183
Mots-clés : Reactor Zeolite Methylation Disproportionation Résumé : An array of zeolites varying in the channel structural design and acidity was investigated in toluene methylation with methanol, together with toluene disproportionation, using fluidized-bed and fixed-bed reactors. The conversions of toluene in the methylation and disproportionation reactions in the fixed-bed reactor were higher than those in the fluidized-bed reactor over the zeolite based catalysts at similar reaction conditions. The unique pore architecture of zeolite TNU-9, with 10-ring channel systems, being slightly larger zeolite compared with ZSM-5, can offer new opportunities for toluene disproportionation, as well as for toluene methylation. The medium pore zeolite TNU-9 was found to possess the highest conversion in toluene disproportionation as compared with other zeolite based catalysts under study. In toluene methylation, the highest toluene conversion was achieved with mordenite based catalyst (MOR-A), while the xylene selectivity follows the order: ZSM-5 > TNU-9 > MOR-A > SSZ-33 > MOR-B. This order indicates that xylene selectivity is directly related to the size of channels from medium to large pore zeolites. Using the fluidized bed, the apparent activation energies for toluene methylation follow the order: ZSM-5 (46.8 kJ/mol) > TNU-9 (33.9 kJ/mol) > MOR-B (13.9 kJ/mol) ≈ MOR-A (13.1 kJ/mol) > SSZ-33 (8.2 kJ/mol). DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944482 Exemplaires
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Titre : Rotating foam stirrer reactor : effect of catalyst coating characteristics on reactor performance Type de document : texte imprimé Auteurs : Maria A. Leon, Auteur ; Roman Tschentscher, Auteur ; T. Alexander Nijhuis, Auteur Année de publication : 2011 Article en page(s) : pp. 3184–3193 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalyst Résumé : Rotating foam stirrer reactors have a promising application in multiphase reactions. In this reactor, highly porous open-celled materials, solid foams, are used both as a catalyst support and as stirrer blades. One of the advantages of such a foam stirrer is easy catalyst handling. This paper presents a preparation method for catalysts on solid foam supports. The performance of the alumina foam catalysts is tested in the hydrogenation of a functionalized alkyne. A stable and homogeneous catalytic coating was deposited on aluminum foams by a combination of anodization and wash coating using the slurry method. Anodization produced a rough and porous material that improved the adhesion of the catalytic coating. The use of a slurry with a bimodal particle size distribution increased the catalytic coating stability. The mass loss of the catalytic coating after applying ultrasonic vibrations was less than 10 wt %, which indicates a good adhesion. A high specific surface area was achieved by increasing the foam cell density, that is, the number of pores per linear inch (ppi), and the catalytic coating thickness. With the wash-coating method, catalytic coatings were produced having a thickness between 10 and 40 μm, a porosity of around 50%, and a specific surface area up to 28.5 m2/gfoam. The hydrogenation of 3-methyl-1-pentyn-3-ol was chosen as the test reaction. Internal and external mass transfers limit the reaction rate of this fast reaction. High activity and selectivity were reached by combining a high specific surface area with a thin catalytic coating on the foam. Increasing the foam cell density up to 20 ppi led to enhanced liquid−solid mass transfer because of the high specific surface area combined with the fast refreshment of the catalyst surface. Coating thicknesses of less than 20 μm led to improved internal mass transfer due to shorter diffusion paths. DEWEY : 6600 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101962g
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3184–3193[article] Rotating foam stirrer reactor : effect of catalyst coating characteristics on reactor performance [texte imprimé] / Maria A. Leon, Auteur ; Roman Tschentscher, Auteur ; T. Alexander Nijhuis, Auteur . - 2011 . - pp. 3184–3193.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3184–3193
Mots-clés : Catalyst Résumé : Rotating foam stirrer reactors have a promising application in multiphase reactions. In this reactor, highly porous open-celled materials, solid foams, are used both as a catalyst support and as stirrer blades. One of the advantages of such a foam stirrer is easy catalyst handling. This paper presents a preparation method for catalysts on solid foam supports. The performance of the alumina foam catalysts is tested in the hydrogenation of a functionalized alkyne. A stable and homogeneous catalytic coating was deposited on aluminum foams by a combination of anodization and wash coating using the slurry method. Anodization produced a rough and porous material that improved the adhesion of the catalytic coating. The use of a slurry with a bimodal particle size distribution increased the catalytic coating stability. The mass loss of the catalytic coating after applying ultrasonic vibrations was less than 10 wt %, which indicates a good adhesion. A high specific surface area was achieved by increasing the foam cell density, that is, the number of pores per linear inch (ppi), and the catalytic coating thickness. With the wash-coating method, catalytic coatings were produced having a thickness between 10 and 40 μm, a porosity of around 50%, and a specific surface area up to 28.5 m2/gfoam. The hydrogenation of 3-methyl-1-pentyn-3-ol was chosen as the test reaction. Internal and external mass transfers limit the reaction rate of this fast reaction. High activity and selectivity were reached by combining a high specific surface area with a thin catalytic coating on the foam. Increasing the foam cell density up to 20 ppi led to enhanced liquid−solid mass transfer because of the high specific surface area combined with the fast refreshment of the catalyst surface. Coating thicknesses of less than 20 μm led to improved internal mass transfer due to shorter diffusion paths. DEWEY : 6600 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101962g Exemplaires
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Titre : Effects of the turbulent - to - laminar transition in monolithic reactors for automotive pollution control Type de document : texte imprimé Auteurs : Henrik Strom, Auteur ; Srdjan Sasic, Auteur ; Bengt Andersson, Auteur Année de publication : 2011 Article en page(s) : pp. 3194-3205 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Pollution abatement control Reactor Monolithic construction Résumé : In the current work a detailed study is performed of the turbulent-to-laminar transition at the inlet of an automotive monolithic reactor. The effects of the transition on the conversion of gaseous species and on the deposition of particulate matter are investigated using numerical simulations. Two main effects of the turbulence on the conversion in the monolith have been identified: slow fluctuations due to turbulent eddies that are too large to enter the channels and rapid fluctuations due to smaller turbulent eddies that penetrate the channels. It is also shown that inertial particles may deposit inside the monolith channels, providing a likely explanation of the experimentally observed spatial deposition profiles of elements that chemically deactivate automotive catalysts. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944484
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3194-3205[article] Effects of the turbulent - to - laminar transition in monolithic reactors for automotive pollution control [texte imprimé] / Henrik Strom, Auteur ; Srdjan Sasic, Auteur ; Bengt Andersson, Auteur . - 2011 . - pp. 3194-3205.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3194-3205
Mots-clés : Pollution abatement control Reactor Monolithic construction Résumé : In the current work a detailed study is performed of the turbulent-to-laminar transition at the inlet of an automotive monolithic reactor. The effects of the transition on the conversion of gaseous species and on the deposition of particulate matter are investigated using numerical simulations. Two main effects of the turbulence on the conversion in the monolith have been identified: slow fluctuations due to turbulent eddies that are too large to enter the channels and rapid fluctuations due to smaller turbulent eddies that penetrate the channels. It is also shown that inertial particles may deposit inside the monolith channels, providing a likely explanation of the experimentally observed spatial deposition profiles of elements that chemically deactivate automotive catalysts. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944484 Exemplaires
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Titre : Modeling hydrolysis and esterification kinetics for biofuel processes Type de document : texte imprimé Auteurs : Shujauddin Changi, Auteur ; Tanawan Pinnarat, Auteur Année de publication : 2011 Article en page(s) : pp. 3206–3211 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetics Résumé : We determined the kinetics for ethyl oleate hydrolysis in high-temperature water and for the reverse reaction, oleic acid esterification, in near- and supercritical ethanol. Hydrolysis was clearly autocatalytic. The experimental data, from reactions at 150−300 °C, times from 5 to 1440 min, and with different initial concentrations of reactants and products, were used to estimate thermodynamically and thermochemically consistent Arrhenius parameters for the forward and reverse reactions in an autocatalytic reaction model. The model provided a good correlation of the data and also exhibited the ability to make quantitatively accurate predictions within the parameter space investigated. The model also accurately predicted the experimental trends when extrapolated outside the original parameter space. Sensitivity analysis confirmed that data from both fatty acid esterification and fatty acid ester hydrolysis need to be used together if one desires reliable estimates for all of the Arrhenius parameters in the autocatalytic model. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1023047
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3206–3211[article] Modeling hydrolysis and esterification kinetics for biofuel processes [texte imprimé] / Shujauddin Changi, Auteur ; Tanawan Pinnarat, Auteur . - 2011 . - pp. 3206–3211.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3206–3211
Mots-clés : Kinetics Résumé : We determined the kinetics for ethyl oleate hydrolysis in high-temperature water and for the reverse reaction, oleic acid esterification, in near- and supercritical ethanol. Hydrolysis was clearly autocatalytic. The experimental data, from reactions at 150−300 °C, times from 5 to 1440 min, and with different initial concentrations of reactants and products, were used to estimate thermodynamically and thermochemically consistent Arrhenius parameters for the forward and reverse reactions in an autocatalytic reaction model. The model provided a good correlation of the data and also exhibited the ability to make quantitatively accurate predictions within the parameter space investigated. The model also accurately predicted the experimental trends when extrapolated outside the original parameter space. Sensitivity analysis confirmed that data from both fatty acid esterification and fatty acid ester hydrolysis need to be used together if one desires reliable estimates for all of the Arrhenius parameters in the autocatalytic model. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1023047 Exemplaires
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Titre : Misting of non - newtonian liquids in forward roll coating Type de document : texte imprimé Auteurs : Michael S. Owens, Auteur ; Madhu Vinjamur, Auteur ; L. E. Scriven, Auteur Année de publication : 2011 Article en page(s) : pp. 1123-1128 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nebulization Dilute solution Polymer solutions Flow visualization Experimental study Roller coating Hydrodynamics Viscoelastic fluid Non-Newtonian fluids Résumé : Misting of liquids in forward roll coating is a problem under certain conditions. The relaxation time is known to influence misting but the fundamental mechanisms are not clear. A new mechanism for misting of dilute non-Newtonian liquids was proposed based on visualizations with a high-speed camera. With these liquids, filaments were created which sometimes transformed into beads-on-string structures and the beads were ejected as mist droplets when the structures broke. Misting was quantified by measuring sizes of the generated droplets, their count and mass concentration. The measurements were related to elasticity of the solutions through their relaxation times. Small levels of elasticity reduce the amount of misting, but higher levels lead to an increase. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24497366
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 1123-1128[article] Misting of non - newtonian liquids in forward roll coating [texte imprimé] / Michael S. Owens, Auteur ; Madhu Vinjamur, Auteur ; L. E. Scriven, Auteur . - 2011 . - pp. 1123-1128.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 1123-1128
Mots-clés : Nebulization Dilute solution Polymer solutions Flow visualization Experimental study Roller coating Hydrodynamics Viscoelastic fluid Non-Newtonian fluids Résumé : Misting of liquids in forward roll coating is a problem under certain conditions. The relaxation time is known to influence misting but the fundamental mechanisms are not clear. A new mechanism for misting of dilute non-Newtonian liquids was proposed based on visualizations with a high-speed camera. With these liquids, filaments were created which sometimes transformed into beads-on-string structures and the beads were ejected as mist droplets when the structures broke. Misting was quantified by measuring sizes of the generated droplets, their count and mass concentration. The measurements were related to elasticity of the solutions through their relaxation times. Small levels of elasticity reduce the amount of misting, but higher levels lead to an increase. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24497366 Exemplaires
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Titre : Amine - modified SBA-15 : effect of pore structure on the performance for CO2 capture Type de document : texte imprimé Auteurs : Xinlong Yan, Auteur ; Lei Zhang, Auteur ; Ying Zhang, Auteur Année de publication : 2011 Article en page(s) : pp. 3220-3226 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Carbon dioxide Pore structure Résumé : Several SBA-15 silica materials with different pore structures were synthesized and functionalized with poly(ethyleneimine) (PEI). The as-prepared materials were characterized by XRD, SEM, TG, FT-IR, and N2 physisorption techniques followed by testing for CO2 capture using a N2 stream containing 15.1 v/v% CO2 in the temperature range of 30- 75 °C. The results showed that the CO2 adsorption capacity linearly increased with the total pore volume of the SBA-15 phases in the tested temperature range (R2 > 0.94). Temperature also showed a strong influence on CO2 adsorption capacity. SBA-15 material with the largest pore volume (1.14 cm3 g-1) exhibited the largest CO2 adsorption capacity (105.2 mg g-1 adsorbent) with 15.1 v/v% CO2 in N2 at 75 °C and atmospheric pressure. Pore size was found not to be the main factor influencing the CO2 adsorption capacity of these PEI-modified SBA-15 materials. Adsorption-desorption cycles (12) revealed that the adsorbents with PEI loaded inside the pore channels were found to be quite stable, as they retained their CO2 adsorption capacity with many cycles. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944487
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3220-3226[article] Amine - modified SBA-15 : effect of pore structure on the performance for CO2 capture [texte imprimé] / Xinlong Yan, Auteur ; Lei Zhang, Auteur ; Ying Zhang, Auteur . - 2011 . - pp. 3220-3226.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3220-3226
Mots-clés : Carbon dioxide Pore structure Résumé : Several SBA-15 silica materials with different pore structures were synthesized and functionalized with poly(ethyleneimine) (PEI). The as-prepared materials were characterized by XRD, SEM, TG, FT-IR, and N2 physisorption techniques followed by testing for CO2 capture using a N2 stream containing 15.1 v/v% CO2 in the temperature range of 30- 75 °C. The results showed that the CO2 adsorption capacity linearly increased with the total pore volume of the SBA-15 phases in the tested temperature range (R2 > 0.94). Temperature also showed a strong influence on CO2 adsorption capacity. SBA-15 material with the largest pore volume (1.14 cm3 g-1) exhibited the largest CO2 adsorption capacity (105.2 mg g-1 adsorbent) with 15.1 v/v% CO2 in N2 at 75 °C and atmospheric pressure. Pore size was found not to be the main factor influencing the CO2 adsorption capacity of these PEI-modified SBA-15 materials. Adsorption-desorption cycles (12) revealed that the adsorbents with PEI loaded inside the pore channels were found to be quite stable, as they retained their CO2 adsorption capacity with many cycles. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944487 Exemplaires
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Titre : Modeling and simulation of vapor - phase synthesis of compound semiconductor nanoparticles in a counterflow jet reactor Type de document : texte imprimé Auteurs : Joungmo Cho, Auteur ; Maria Koutsona, Auteur ; Christos Sarigiannidis, Auteur Année de publication : 2011 Article en page(s) : pp. 3227–3238 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Vapor phase Nanoparticles Résumé : A mathematical model describing the vapor-phase synthesis of II−VI compound semiconductor nanoparticles in a counterflow jet reactor has been developed. The model was used to perform parametric studies in order to identify optimal operating conditions and reactor configurations that maximize particle yield, minimize polydispersity, and enable synthesis of particles with average size smaller than the quantum confinement threshold, i.e., quantum dots. The synthesis of zinc selenide nanoparticles by reacting vapors of dimethyl zinc with hydrogen selenide gas under isothermal conditions at 300 K was used as an example. In the experimental system, the two precursors were diluted in hydrogen carrier gas and each was fed into the reactor from a different inlet of an opposed-flow configuration. A steady-state reaction-transport model was developed to describe the laminar flow of the hydrogen carrier gas in the reactor, mass transfer of the precursors by convection and diffusion, and nucleation of particles through an irreversible reaction between the precursors. The reaction-transport model was coupled to an aerosol dynamics model describing particle transport by diffusion and convection, and particle growth by coagulation. The Galerkin finite element method was used to solve the resulting system of partial differential equations in the axial and radial directions of a cylindrical domain by assuming rotational symmetry. The only fitted parameter of the model was the activation energy for coagulation whose value was estimated by comparing model predictions with experimental data from a laboratory-scale reactor. A parametric study was performed to identify optimal operating conditions and a reactor configuration that maximizes particle yield, minimizes polydispersity, and enables the synthesis of particles with average size below the confinement threshold of 9 nm for zinc selenide. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101354e
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3227–3238[article] Modeling and simulation of vapor - phase synthesis of compound semiconductor nanoparticles in a counterflow jet reactor [texte imprimé] / Joungmo Cho, Auteur ; Maria Koutsona, Auteur ; Christos Sarigiannidis, Auteur . - 2011 . - pp. 3227–3238.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3227–3238
Mots-clés : Vapor phase Nanoparticles Résumé : A mathematical model describing the vapor-phase synthesis of II−VI compound semiconductor nanoparticles in a counterflow jet reactor has been developed. The model was used to perform parametric studies in order to identify optimal operating conditions and reactor configurations that maximize particle yield, minimize polydispersity, and enable synthesis of particles with average size smaller than the quantum confinement threshold, i.e., quantum dots. The synthesis of zinc selenide nanoparticles by reacting vapors of dimethyl zinc with hydrogen selenide gas under isothermal conditions at 300 K was used as an example. In the experimental system, the two precursors were diluted in hydrogen carrier gas and each was fed into the reactor from a different inlet of an opposed-flow configuration. A steady-state reaction-transport model was developed to describe the laminar flow of the hydrogen carrier gas in the reactor, mass transfer of the precursors by convection and diffusion, and nucleation of particles through an irreversible reaction between the precursors. The reaction-transport model was coupled to an aerosol dynamics model describing particle transport by diffusion and convection, and particle growth by coagulation. The Galerkin finite element method was used to solve the resulting system of partial differential equations in the axial and radial directions of a cylindrical domain by assuming rotational symmetry. The only fitted parameter of the model was the activation energy for coagulation whose value was estimated by comparing model predictions with experimental data from a laboratory-scale reactor. A parametric study was performed to identify optimal operating conditions and a reactor configuration that maximizes particle yield, minimizes polydispersity, and enables the synthesis of particles with average size below the confinement threshold of 9 nm for zinc selenide. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101354e Exemplaires
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Titre : Process intensification in particle technology : production of powder coatings by nonisothermal flow - induced phase inversion Type de document : texte imprimé Auteurs : Galip Akay, Auteur ; Bandara Dissanayake, Auteur ; Andy Morgan, Auteur Année de publication : 2011 Article en page(s) : pp.3239–3246 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nonisothermal flow Induced phase Résumé : A novel intensive granulation process for the production of powder coatings is described. The method is based on nonisothermal flow-induced phase inversion (FIPI) phenomenon. A powder coating composition in melt state is transformed to coating particles in a purpose-built granulator that operates in a rotor−stator configuration in which rotor−stator elements have cavities to achieve mixing, pumping, particulate conveying, heat transfer, and crumbling (phase inversion) which takes place at a certain distance (radius) from the center of the disk. The rotor disk is sandwiched between two stator disks. Heat transfer is further improved and melt quenching under deformation is achieved by injecting water or carbon dioxide into the melt while a temperature gradient is maintained across the upper rotor and stator. Injection of fluids reduced the average particle size of the product considerably and also intensified the granulation process through crumbling in a small volume when the coating melt is transformed to particles. The product was characterized by particle size analysis. Methods to control the crumbling radius and average particle size well-below the rotor−stator gap are discussed. The influence of fluid (water or carbon dioxide) injection on the granulation mechanism and the extension of the method to cylindrical rotor−stator system are also discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101516r
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp.3239–3246[article] Process intensification in particle technology : production of powder coatings by nonisothermal flow - induced phase inversion [texte imprimé] / Galip Akay, Auteur ; Bandara Dissanayake, Auteur ; Andy Morgan, Auteur . - 2011 . - pp.3239–3246.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp.3239–3246
Mots-clés : Nonisothermal flow Induced phase Résumé : A novel intensive granulation process for the production of powder coatings is described. The method is based on nonisothermal flow-induced phase inversion (FIPI) phenomenon. A powder coating composition in melt state is transformed to coating particles in a purpose-built granulator that operates in a rotor−stator configuration in which rotor−stator elements have cavities to achieve mixing, pumping, particulate conveying, heat transfer, and crumbling (phase inversion) which takes place at a certain distance (radius) from the center of the disk. The rotor disk is sandwiched between two stator disks. Heat transfer is further improved and melt quenching under deformation is achieved by injecting water or carbon dioxide into the melt while a temperature gradient is maintained across the upper rotor and stator. Injection of fluids reduced the average particle size of the product considerably and also intensified the granulation process through crumbling in a small volume when the coating melt is transformed to particles. The product was characterized by particle size analysis. Methods to control the crumbling radius and average particle size well-below the rotor−stator gap are discussed. The influence of fluid (water or carbon dioxide) injection on the granulation mechanism and the extension of the method to cylindrical rotor−stator system are also discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101516r Exemplaires
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Titre : Effect of growing crystalline phase on bubble nucleation in poly(L - Lactide)/CO2 batch foaming Type de document : texte imprimé Auteurs : Kentaro Taki, Auteur ; Daisaku Kitano, Auteur ; Masahiro Ohshima, Auteur Année de publication : 2011 Article en page(s) : pp. 3247–3252 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Crystalline phase Résumé : Creating a high-efficiency bubble nucleation agent for a polymer foaming process is essential for increasing bubble density as well as decreasing bubble size. Spherulites (crystalline phase) grown in a semicrystalline poly(L-lactide) (PLLA) matrix enhanced carbon dioxide (CO2) bubble nucleation in a batch foaming process. Several sites for PLLA spherulite formation were observed at a hold-temperature of 110 °C after CO2 saturation in molten PLLA, which was heated to 180 °C at 11 MPa. By depressurizing the system from 11 MPa to atmospheric pressure, the dissolved CO2 in the PLLA matrix became supersaturated, and CO2 bubbles nucleated around growing PLLA spherulites. The number of nucleating bubbles increased as a function of increasing spherulite quantity and area. A faster linear spherulite growth rate and a lower hold-temperature created more bubbles around the spherulites. From these observations, it was concluded that the growing spherulites expelled CO2 from the advancing spherulite−amorphous phase interface and that CO2 accumulated at the interface. Then, the increase in the concentration of CO2 led to an increase in the nucleation of bubbles around the spherulites. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101637f
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3247–3252[article] Effect of growing crystalline phase on bubble nucleation in poly(L - Lactide)/CO2 batch foaming [texte imprimé] / Kentaro Taki, Auteur ; Daisaku Kitano, Auteur ; Masahiro Ohshima, Auteur . - 2011 . - pp. 3247–3252.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3247–3252
Mots-clés : Crystalline phase Résumé : Creating a high-efficiency bubble nucleation agent for a polymer foaming process is essential for increasing bubble density as well as decreasing bubble size. Spherulites (crystalline phase) grown in a semicrystalline poly(L-lactide) (PLLA) matrix enhanced carbon dioxide (CO2) bubble nucleation in a batch foaming process. Several sites for PLLA spherulite formation were observed at a hold-temperature of 110 °C after CO2 saturation in molten PLLA, which was heated to 180 °C at 11 MPa. By depressurizing the system from 11 MPa to atmospheric pressure, the dissolved CO2 in the PLLA matrix became supersaturated, and CO2 bubbles nucleated around growing PLLA spherulites. The number of nucleating bubbles increased as a function of increasing spherulite quantity and area. A faster linear spherulite growth rate and a lower hold-temperature created more bubbles around the spherulites. From these observations, it was concluded that the growing spherulites expelled CO2 from the advancing spherulite−amorphous phase interface and that CO2 accumulated at the interface. Then, the increase in the concentration of CO2 led to an increase in the nucleation of bubbles around the spherulites. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101637f Exemplaires
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Titre : Effective solution mixing method to fabricate highly transparent and optical functional organic — inorganic nanocomposite film Type de document : texte imprimé Auteurs : Xiao - Fei Zeng, Auteur ; Xian - Rong Kong, Auteur ; Jun - Lin Ge, Auteur Année de publication : 2011 Article en page(s) : pp. 3253-3258 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nanocomposite Mixing Résumé : The organic-inorganic hybrid optical materials with a high transmittance of visible-light have shown great potential applications. However, it is still in challenge to maintain the transparency of optical materials when the inorganic nanoparticles (NPs) are introduced into the polymer matrix because of Rayleigh scattering caused by the severely aggregation of NPs, which is a huge obstacle for its applications. This article reports a transparent "solution" mixing method to fabricate a highly transparent nanocomposite film of zinc oxide (ZnO)/poly (methyl methacrylate)-co-poly (styrene) (PMMA-PS) with the novel UV-shielding properties. The transparent "solution" containing nanoparticles was prepared by phase-transfer of ZnO NPs suspension in hexane to NPs dispersion in toluene with surface modifier. The latter dispersion had the complete transparency as a solution (so-called "solution"). It was found that the incorporation of ZnO NPs not only provided UV-shielding ability to the PMMA-PS nanocomposite film with the same transparency of the pure PMMA-PS film, but also improved the thermal stability of the film. When 2% of the ZnO NPs were added into the PMMA-PS polymer, the nanocomposite film could block UV radiation at 350 nm up to 97% and allow 98% transmittance ofvisible light at 400 nm. The SEM and TEM studies further confirmed that the ZnO NPs were well distributed in the PMMA-PS polymer matrix with the maximum aggregated nanoparticle size less than 20 nm in diameter. High thermal stability was achieved with a 37 °C increase in the initial decomposition temperature of such nanocomposite compared to the pure PMMA-PS. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944491
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3253-3258[article] Effective solution mixing method to fabricate highly transparent and optical functional organic — inorganic nanocomposite film [texte imprimé] / Xiao - Fei Zeng, Auteur ; Xian - Rong Kong, Auteur ; Jun - Lin Ge, Auteur . - 2011 . - pp. 3253-3258.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3253-3258
Mots-clés : Nanocomposite Mixing Résumé : The organic-inorganic hybrid optical materials with a high transmittance of visible-light have shown great potential applications. However, it is still in challenge to maintain the transparency of optical materials when the inorganic nanoparticles (NPs) are introduced into the polymer matrix because of Rayleigh scattering caused by the severely aggregation of NPs, which is a huge obstacle for its applications. This article reports a transparent "solution" mixing method to fabricate a highly transparent nanocomposite film of zinc oxide (ZnO)/poly (methyl methacrylate)-co-poly (styrene) (PMMA-PS) with the novel UV-shielding properties. The transparent "solution" containing nanoparticles was prepared by phase-transfer of ZnO NPs suspension in hexane to NPs dispersion in toluene with surface modifier. The latter dispersion had the complete transparency as a solution (so-called "solution"). It was found that the incorporation of ZnO NPs not only provided UV-shielding ability to the PMMA-PS nanocomposite film with the same transparency of the pure PMMA-PS film, but also improved the thermal stability of the film. When 2% of the ZnO NPs were added into the PMMA-PS polymer, the nanocomposite film could block UV radiation at 350 nm up to 97% and allow 98% transmittance ofvisible light at 400 nm. The SEM and TEM studies further confirmed that the ZnO NPs were well distributed in the PMMA-PS polymer matrix with the maximum aggregated nanoparticle size less than 20 nm in diameter. High thermal stability was achieved with a 37 °C increase in the initial decomposition temperature of such nanocomposite compared to the pure PMMA-PS. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944491 Exemplaires
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Titre : Effect of functionalized nanomaterials on the rheology of borate cross - linked guar gum Type de document : texte imprimé Auteurs : Huma R. Jafry, Auteur ; Matteo Pasquali, Auteur ; Andrew R. Barron, Auteur Année de publication : 2011 Article en page(s) : pp. 3259–3264 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nanomaterials Rheology Résumé : This study provides an insight into the effect of incorporating nanoparticles on the rheology of fracturing fluids. Vapor grown carbon fibers (VGCFs) are first coated with silica and subsequently functionalized with octadecyltrichlorosilane groups. These coated and functionalized fibers are then added to a fracturing fluid gel. XPS and rheological measurements are performed to understand the interactions and effects of VGCFs coated with silica and functionalized with silane group on the viscosity and storage modulus of the fracturing gels at three different pHs: 8.6, 9.3, and 10.3. The addition of the ODS−SiO2−VGCF to the guar gels exhibits an interaction with the gels only at a lower pH than typically used for fracturing fluids. While the presence of ODS−SiO2−VGCF minimally increases the storage modulus of the guar gels, under shear-induced conditions, gels which contain ODS−SiO2−VGCF behave similarly to the plain guar gels, displaying no permanent damage to the gels under the applied shear. The presence of ODS−SiO2−VGCF does not appear to alter the structure and the cross-links of the guar gel. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101836z
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3259–3264[article] Effect of functionalized nanomaterials on the rheology of borate cross - linked guar gum [texte imprimé] / Huma R. Jafry, Auteur ; Matteo Pasquali, Auteur ; Andrew R. Barron, Auteur . - 2011 . - pp. 3259–3264.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3259–3264
Mots-clés : Nanomaterials Rheology Résumé : This study provides an insight into the effect of incorporating nanoparticles on the rheology of fracturing fluids. Vapor grown carbon fibers (VGCFs) are first coated with silica and subsequently functionalized with octadecyltrichlorosilane groups. These coated and functionalized fibers are then added to a fracturing fluid gel. XPS and rheological measurements are performed to understand the interactions and effects of VGCFs coated with silica and functionalized with silane group on the viscosity and storage modulus of the fracturing gels at three different pHs: 8.6, 9.3, and 10.3. The addition of the ODS−SiO2−VGCF to the guar gels exhibits an interaction with the gels only at a lower pH than typically used for fracturing fluids. While the presence of ODS−SiO2−VGCF minimally increases the storage modulus of the guar gels, under shear-induced conditions, gels which contain ODS−SiO2−VGCF behave similarly to the plain guar gels, displaying no permanent damage to the gels under the applied shear. The presence of ODS−SiO2−VGCF does not appear to alter the structure and the cross-links of the guar gel. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101836z Exemplaires
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Titre : Preparing mesoporous low - k films with high mechanical strength from noncrystalline silica particles Type de document : texte imprimé Auteurs : Hsin - Yan Lu, Auteur ; Chin - Lin Teng, Auteur ; Chien - Hao Kung, Auteur Année de publication : 2011 Article en page(s) : pp. 3265-3273 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Strength Résumé : The coating solutions composed of surfactant Tween 80 and noncrystalline silica particles with an average size of 4.6 nm were synthesized through a short hydrothermal process. They were spun onto silicon wafers to obtain mesoporous low-k films. The film properties were compared with those of the films made of MFI zeolite nanocrystals with an average size of around 40 nm. The films from noncrystalline particles showed higher surface uniformity and higher mechanical strength, and possessed k values of smaller than 2 and low leakage current densities, which all reached the needs of the future IC industry. The preparation processes and time for the noncrystalline silica particles are much simpler and shorter than those for the MFI zeolite nanocrystals. As a result, the processes developed in this research can save the production cost and time for producing low-k films in the future. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944493
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3265-3273[article] Preparing mesoporous low - k films with high mechanical strength from noncrystalline silica particles [texte imprimé] / Hsin - Yan Lu, Auteur ; Chin - Lin Teng, Auteur ; Chien - Hao Kung, Auteur . - 2011 . - pp. 3265-3273.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3265-3273
Mots-clés : Strength Résumé : The coating solutions composed of surfactant Tween 80 and noncrystalline silica particles with an average size of 4.6 nm were synthesized through a short hydrothermal process. They were spun onto silicon wafers to obtain mesoporous low-k films. The film properties were compared with those of the films made of MFI zeolite nanocrystals with an average size of around 40 nm. The films from noncrystalline particles showed higher surface uniformity and higher mechanical strength, and possessed k values of smaller than 2 and low leakage current densities, which all reached the needs of the future IC industry. The preparation processes and time for the noncrystalline silica particles are much simpler and shorter than those for the MFI zeolite nanocrystals. As a result, the processes developed in this research can save the production cost and time for producing low-k films in the future. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944493 Exemplaires
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Titre : Amino - functionalized polyethylene for enhancing the adhesion between polyolefins and polyurethanes Type de document : texte imprimé Auteurs : Shingo Kobayashi, Auteur ; Jie Song, Auteur ; H. Craig Silvis, Auteur Année de publication : 2011 Article en page(s) : pp. 3274–3279 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Polyethylenes Résumé : Primary and secondary amino-functionalized polyethylenes were synthesized from commercially available maleic anhydride-modified polyethylene by reaction with mono-tert-butoxycarbonyl-protected diamines, N-(tert-butoxycarbonyl)-1,6-diaminohexane (tBocHMDA), and N-(tert-butoxycarbonyl)-N-ethyl-1,6-diaminohexane (tBocEtHMDA) followed by deprotection with trifluoroacetic acid. The structures of amino-functionalized polyethylenes were characterized by NMR and IR spectroscopies, and the data compared favorably to that of the corresponding model compounds. The amino-functionalized polymers showed significantly improved adhesive strength toward thermoplastic polyurethanes as compared to the parent maleic anhydride-modified polyethylene. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102005q
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3274–3279[article] Amino - functionalized polyethylene for enhancing the adhesion between polyolefins and polyurethanes [texte imprimé] / Shingo Kobayashi, Auteur ; Jie Song, Auteur ; H. Craig Silvis, Auteur . - 2011 . - pp. 3274–3279.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3274–3279
Mots-clés : Polyethylenes Résumé : Primary and secondary amino-functionalized polyethylenes were synthesized from commercially available maleic anhydride-modified polyethylene by reaction with mono-tert-butoxycarbonyl-protected diamines, N-(tert-butoxycarbonyl)-1,6-diaminohexane (tBocHMDA), and N-(tert-butoxycarbonyl)-N-ethyl-1,6-diaminohexane (tBocEtHMDA) followed by deprotection with trifluoroacetic acid. The structures of amino-functionalized polyethylenes were characterized by NMR and IR spectroscopies, and the data compared favorably to that of the corresponding model compounds. The amino-functionalized polymers showed significantly improved adhesive strength toward thermoplastic polyurethanes as compared to the parent maleic anhydride-modified polyethylene. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102005q Exemplaires
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Titre : Effects of rotation of benzene rings on diffusion of solvents in polymer melts Type de document : texte imprimé Auteurs : Makoto Asai, Auteur ; Megumi Awata, Auteur ; Yasuhiro Koike, Auteur Année de publication : 2011 Article en page(s) : pp. 3280–3286 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Solvents Polymer Résumé : Diffusion of a solvent through a polymer is one of the important phenomena in the industry. Such diffusion phenomena, however, have complicated multibody problems, and in general, they are difficult to tightly control. In this study, it was our objective to investigate the effects of the structure of the solvent on the diffusion in polymers, in particular, the effects of the structure on concentration dependence of a mutual diffusion coefficient. Knowledge pertaining to chemical structures and diffusion is very useful for controlling the diffusion phenomena because it allows the design of a solvent possessing the desired diffusion. The diffusion of diphenylsulfide and dibenzothiophene in poly(methyl methacrylate) (PMMA) was investigated. Diphenylsulfide and dibenzothiophene have nearly identical molecular structures and differ in a benzene ring with or without rotation within the molecule. The results indicated that the dependence of the mutual diffusion coefficient was significantly affected by the rotation of the benzene ring present in the molecule. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102082r
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3280–3286[article] Effects of rotation of benzene rings on diffusion of solvents in polymer melts [texte imprimé] / Makoto Asai, Auteur ; Megumi Awata, Auteur ; Yasuhiro Koike, Auteur . - 2011 . - pp. 3280–3286.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3280–3286
Mots-clés : Solvents Polymer Résumé : Diffusion of a solvent through a polymer is one of the important phenomena in the industry. Such diffusion phenomena, however, have complicated multibody problems, and in general, they are difficult to tightly control. In this study, it was our objective to investigate the effects of the structure of the solvent on the diffusion in polymers, in particular, the effects of the structure on concentration dependence of a mutual diffusion coefficient. Knowledge pertaining to chemical structures and diffusion is very useful for controlling the diffusion phenomena because it allows the design of a solvent possessing the desired diffusion. The diffusion of diphenylsulfide and dibenzothiophene in poly(methyl methacrylate) (PMMA) was investigated. Diphenylsulfide and dibenzothiophene have nearly identical molecular structures and differ in a benzene ring with or without rotation within the molecule. The results indicated that the dependence of the mutual diffusion coefficient was significantly affected by the rotation of the benzene ring present in the molecule. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102082r Exemplaires
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Titre : Absorption capability and inkjet ink colorant penetration into binders commonly used in pigmented paper coatings Type de document : texte imprimé Auteurs : T. T. Lamminmaki, Auteur ; J. P. Kettle, Auteur ; P. J. T. Puukko, Auteur Année de publication : 2011 Article en page(s) : pp. 3287–3294 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Absorption coating Résumé : The absorption of coating binders used in inkjet coatings plays an important role apart from that of the porosity and pore structure of the pigment coating layer. The aim of this work is to clarify how different binder films absorb water-based dye-containing inks and how changes in the ionic nature of both ink dye and binder films affect the ink absorption capability and the final colorant location in the binder film. The studied commercial binders were one carboxylated, and a range of partially hydrolyzed and fully hydrolyzed polyvinyl alcohol (PVOH), and these were compared to an anionic styrene acrylic latex. The hydrolysis modifies the effective crystallinity and hence the swelling tendency. The results show that as the hydrophobicity of the PVOH binder increases, the less the binder absorbs the water-based ink vehicle and the colorant of the ink locates/fixes more on the top part of the coating structure. Both ink vehicle and dye colorant diffuse into the binder film. It was observed that the carboxylated PVOH film produces the most intense coloration (darkest blue color of cyan ink) as the greater ink vehicle absorption promotes the high colorant amount in the film. The combination of opposite charges of the binder film and dye-based ink colorant fixes the colorant most effectively to the top part of the film by the action of chromatographic separation and adsorption. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102178x
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3287–3294[article] Absorption capability and inkjet ink colorant penetration into binders commonly used in pigmented paper coatings [texte imprimé] / T. T. Lamminmaki, Auteur ; J. P. Kettle, Auteur ; P. J. T. Puukko, Auteur . - 2011 . - pp. 3287–3294.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3287–3294
Mots-clés : Absorption coating Résumé : The absorption of coating binders used in inkjet coatings plays an important role apart from that of the porosity and pore structure of the pigment coating layer. The aim of this work is to clarify how different binder films absorb water-based dye-containing inks and how changes in the ionic nature of both ink dye and binder films affect the ink absorption capability and the final colorant location in the binder film. The studied commercial binders were one carboxylated, and a range of partially hydrolyzed and fully hydrolyzed polyvinyl alcohol (PVOH), and these were compared to an anionic styrene acrylic latex. The hydrolysis modifies the effective crystallinity and hence the swelling tendency. The results show that as the hydrophobicity of the PVOH binder increases, the less the binder absorbs the water-based ink vehicle and the colorant of the ink locates/fixes more on the top part of the coating structure. Both ink vehicle and dye colorant diffuse into the binder film. It was observed that the carboxylated PVOH film produces the most intense coloration (darkest blue color of cyan ink) as the greater ink vehicle absorption promotes the high colorant amount in the film. The combination of opposite charges of the binder film and dye-based ink colorant fixes the colorant most effectively to the top part of the film by the action of chromatographic separation and adsorption. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102178x Exemplaires
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Titre : Improved antifouling property of polyethersulfone hollow fiber membranes using additive of poly(ethylene glycol) methyl ether-b - poly(styrene) copolymers Type de document : texte imprimé Auteurs : Weifeng Zhao, Auteur ; Chao He, Auteur ; Huiyuan Wang, Auteur Année de publication : 2011 Article en page(s) : pp. 3295-3303 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Additive Hollow fiber Résumé : Well-defined block copolymers, poly(ethylene glycol) methyl ether-b-poly(styrene) (mPEG-b-PS), in which the PS blocks had different molecular weights, were synthesized by atom-transfer radical polymerization (ATRP) and characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and gel permeation chromatography (GPC). The block copolymers were then used as amphiphilic additives to modify polyethersulfone (PES) hollow fiber membranes to improve the antifouling property. Static contact angle measurement indicated the increase of the membrane surface hydrophilicity, and scanning electron micrograph (SEM) suggested that the modified membranes preserved asymmetric structure. Protein ultrafiltration experiments showed that the antifouling ability of the modified membranes enhanced. After three cycles of BSA solution (1.0 mg/mL) ultrafiltration and three times of hydraulic cleaning, the water flux recovery ratios (FRR) of the mPEG-b-PS modified membranes were still as high as 85.6%. The hydrophilic modification with mPEG-b-PS copolymers is a good method to improve the antifouling property of PES hollow fiber membranes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944497
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3295-3303[article] Improved antifouling property of polyethersulfone hollow fiber membranes using additive of poly(ethylene glycol) methyl ether-b - poly(styrene) copolymers [texte imprimé] / Weifeng Zhao, Auteur ; Chao He, Auteur ; Huiyuan Wang, Auteur . - 2011 . - pp. 3295-3303.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3295-3303
Mots-clés : Additive Hollow fiber Résumé : Well-defined block copolymers, poly(ethylene glycol) methyl ether-b-poly(styrene) (mPEG-b-PS), in which the PS blocks had different molecular weights, were synthesized by atom-transfer radical polymerization (ATRP) and characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and gel permeation chromatography (GPC). The block copolymers were then used as amphiphilic additives to modify polyethersulfone (PES) hollow fiber membranes to improve the antifouling property. Static contact angle measurement indicated the increase of the membrane surface hydrophilicity, and scanning electron micrograph (SEM) suggested that the modified membranes preserved asymmetric structure. Protein ultrafiltration experiments showed that the antifouling ability of the modified membranes enhanced. After three cycles of BSA solution (1.0 mg/mL) ultrafiltration and three times of hydraulic cleaning, the water flux recovery ratios (FRR) of the mPEG-b-PS modified membranes were still as high as 85.6%. The hydrophilic modification with mPEG-b-PS copolymers is a good method to improve the antifouling property of PES hollow fiber membranes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944497 Exemplaires
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Titre : Byproduct hydrogen network design using pressure swing adsorption and recycling unit for the petrochemical complex Type de document : texte imprimé Auteurs : Changhyun Jeong, Auteur ; Chonghun Han, Auteur Année de publication : 2011 Article en page(s) : pp. 3304-3311 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Petrochemical industry Recycling Pressure swing adsorption Design Résumé : Hydrogen, which has gained attention as the next-generation renewable energy source among byproducts, is a raw material that is commonly produced and consumed in all petrochemical complexes. It is also a primary energy source in energy systems that can considerably reduce air pollution and greenhouse gas emission. Therefore, an explosive demand for hydrogen is expected in the future. A considerable amount of hydrogen is produced as byproducts in industrial complexes such as petrochemical plants and oil refineries within a petrochemical complex; however, this hydrogen is mostly used as fuel internally. If a considerable amount of hydrogen that is used as fuel can be recycled as raw material for an energy source or for other processes, hydrogen can be of a considerably higher value than it is at present. In this research, we have designed a byproduct hydrogen network between a source and a sink within a petrochemical complex. We determined the minimum fresh hydrogen and recovery hydrogen that are needed for forming a material exchange network through hydrogen pinch analysis and finally designed the hydrogen recycling network between the source plant and the sink plant by building a network optimization problem in which the cost and constraints needed to build the network were considered. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944498
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3304-3311[article] Byproduct hydrogen network design using pressure swing adsorption and recycling unit for the petrochemical complex [texte imprimé] / Changhyun Jeong, Auteur ; Chonghun Han, Auteur . - 2011 . - pp. 3304-3311.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3304-3311
Mots-clés : Petrochemical industry Recycling Pressure swing adsorption Design Résumé : Hydrogen, which has gained attention as the next-generation renewable energy source among byproducts, is a raw material that is commonly produced and consumed in all petrochemical complexes. It is also a primary energy source in energy systems that can considerably reduce air pollution and greenhouse gas emission. Therefore, an explosive demand for hydrogen is expected in the future. A considerable amount of hydrogen is produced as byproducts in industrial complexes such as petrochemical plants and oil refineries within a petrochemical complex; however, this hydrogen is mostly used as fuel internally. If a considerable amount of hydrogen that is used as fuel can be recycled as raw material for an energy source or for other processes, hydrogen can be of a considerably higher value than it is at present. In this research, we have designed a byproduct hydrogen network between a source and a sink within a petrochemical complex. We determined the minimum fresh hydrogen and recovery hydrogen that are needed for forming a material exchange network through hydrogen pinch analysis and finally designed the hydrogen recycling network between the source plant and the sink plant by building a network optimization problem in which the cost and constraints needed to build the network were considered. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944498 Exemplaires
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Titre : Design and control of a vapor - phase conventional process and reactive distillation process for cumene production Type de document : texte imprimé Auteurs : Ashok S. Pathak, Auteur ; Sankalp Agarwal, Auteur ; Vivek Gera, Auteur Année de publication : 2011 Article en page(s) : pp. 3312–3326 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Cumene production Résumé : The economic optimum design and plantwide control of two alternative processes for cumene manufacture, a conventional process using a vapor-phase packed bed reactor and a reactive distillation (RD) process, are compared in this work. In terms of the total annualized cost (TAC), the RD process is a significant 47% cheaper than the conventional process. This is attributed to the lower capital and energy costs due to process integration. The RD process yield to desired product is also higher. Effective decentralized plantwide regulatory control structures exhibiting good load rejection characteristics are developed for the two processes. A two-point temperature inferential control structure on the RD column is found to work well. The RD process thus appears a promising alternative to the conventional process. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100779k
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3312–3326[article] Design and control of a vapor - phase conventional process and reactive distillation process for cumene production [texte imprimé] / Ashok S. Pathak, Auteur ; Sankalp Agarwal, Auteur ; Vivek Gera, Auteur . - 2011 . - pp. 3312–3326.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3312–3326
Mots-clés : Cumene production Résumé : The economic optimum design and plantwide control of two alternative processes for cumene manufacture, a conventional process using a vapor-phase packed bed reactor and a reactive distillation (RD) process, are compared in this work. In terms of the total annualized cost (TAC), the RD process is a significant 47% cheaper than the conventional process. This is attributed to the lower capital and energy costs due to process integration. The RD process yield to desired product is also higher. Effective decentralized plantwide regulatory control structures exhibiting good load rejection characteristics are developed for the two processes. A two-point temperature inferential control structure on the RD column is found to work well. The RD process thus appears a promising alternative to the conventional process. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100779k Exemplaires
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Titre : Proportional - integral-Derivative tuning for servo/regulation control operation for unstable and integrating processes Type de document : texte imprimé Auteurs : O. Arrieta, Auteur ; R. Vilanova, Auteur ; A. Visioli, Auteur Année de publication : 2011 Article en page(s) : pp. 3327–3334 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Servo Integrating processes Résumé : The control of stable processes using PI/PID controllers is by now a well established and understood problem (even if new methods and approaches are continuously appearing). However, when the process has integrating or unstable characteristics the problem becomes much more difficult to manage. Several proposals have appeared in the literature presenting different approaches to tackle the problem. The procedures that have been proposed heavily concentrate on tunings for servo or regulation operation. A common drawback of such approaches is the high loss of performance when the other operation mode is used. In this paper, an approach for providing a unique tuning is presented. It combines tunings for both operation modes in such a way that the performance degradation is traded-off. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101012z
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3327–3334[article] Proportional - integral-Derivative tuning for servo/regulation control operation for unstable and integrating processes [texte imprimé] / O. Arrieta, Auteur ; R. Vilanova, Auteur ; A. Visioli, Auteur . - 2011 . - pp. 3327–3334.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3327–3334
Mots-clés : Servo Integrating processes Résumé : The control of stable processes using PI/PID controllers is by now a well established and understood problem (even if new methods and approaches are continuously appearing). However, when the process has integrating or unstable characteristics the problem becomes much more difficult to manage. Several proposals have appeared in the literature presenting different approaches to tackle the problem. The procedures that have been proposed heavily concentrate on tunings for servo or regulation operation. A common drawback of such approaches is the high loss of performance when the other operation mode is used. In this paper, an approach for providing a unique tuning is presented. It combines tunings for both operation modes in such a way that the performance degradation is traded-off. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101012z Exemplaires
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Titre : Optimization of scaled parameters and setting minimum rule base for a fuzzy controller in a lab - scale pH process Type de document : texte imprimé Auteurs : O. Aras, Auteur ; M. Bayramoglu, Auteur ; A.S. Hasiloglu, Auteur Année de publication : 2011 Article en page(s) : pp. 3335-3344 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : pH Optimization Résumé : Experimental and simulation studies were conducted to design a multiregional fuzzy logic controller (FLC) for a lab-scale pH process system. Scaled coefficients of the controller were optimized offline to obtain the best controller performance in terms of cost function and function evaluation number using two widely used global optimization methods; namely, Genetic Algorithm (GA) and Particle Swarm Optimization (PSO). Various tuning parameters of these optimization algorithms were investigated in detail to compare their performance on this subject. The cost functions obtained via two algorithms were very close to each other, but the function evaluation number was almost 4-fold due to complicated computation of the GA compared to the PSO. On the other side, working with the PSO was much easier owing to fewer adjustable parameters. In the second part of the study, the rule base of the controller was minimized using two different new methods. In this context, the number of rules was reduced by 43% and 56% using the fuzzy matching set and the personal initiative methods, respectively. Rule base reduction increased the performance and the effectiveness of the controller, an important issue for real-time applications. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944501
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3335-3344[article] Optimization of scaled parameters and setting minimum rule base for a fuzzy controller in a lab - scale pH process [texte imprimé] / O. Aras, Auteur ; M. Bayramoglu, Auteur ; A.S. Hasiloglu, Auteur . - 2011 . - pp. 3335-3344.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3335-3344
Mots-clés : pH Optimization Résumé : Experimental and simulation studies were conducted to design a multiregional fuzzy logic controller (FLC) for a lab-scale pH process system. Scaled coefficients of the controller were optimized offline to obtain the best controller performance in terms of cost function and function evaluation number using two widely used global optimization methods; namely, Genetic Algorithm (GA) and Particle Swarm Optimization (PSO). Various tuning parameters of these optimization algorithms were investigated in detail to compare their performance on this subject. The cost functions obtained via two algorithms were very close to each other, but the function evaluation number was almost 4-fold due to complicated computation of the GA compared to the PSO. On the other side, working with the PSO was much easier owing to fewer adjustable parameters. In the second part of the study, the rule base of the controller was minimized using two different new methods. In this context, the number of rules was reduced by 43% and 56% using the fuzzy matching set and the personal initiative methods, respectively. Rule base reduction increased the performance and the effectiveness of the controller, an important issue for real-time applications. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944501 Exemplaires
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Titre : Hidden semi - markov probability models for monitoring two-dimensional batch operation Type de document : texte imprimé Auteurs : Junghui Chen, Auteur ; Yan-Cheng Jiang, Auteur Année de publication : 2011 Article en page(s) : pp. 3345–3355 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Dynamic Probability Résumé : The repetitive batch operation has a two-dimensional dynamic behavior, including a finite time interval of each batch run in the time domain and infinite repetitions along the batch domain. In this Article, a novel monitoring method that combines dynamic multiway principal component analysis (DMPCA) and hidden segmental semi-Markov models (HSMM) is proposed to resolve the problem caused by the two-dimensional behavior of batch processes. DMPCA utilizes the batch-to-batch dynamic characteristics and eliminates the batch correlation among process variables. HSMM is used to construct the temporal behavior among process variables during each batch run. By constructing a two-dimensional model, the proposed method can generate simple probability monitoring charts and monitor the progress in each batch run. The proposed method has the temporal property of HSMM and the batch-to-batch dynamic characteristics of DMPCA. Its advantages are demonstrated through a simulated fed-batch penicillin cultivation process characterized by fault sources. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101189g
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3345–3355[article] Hidden semi - markov probability models for monitoring two-dimensional batch operation [texte imprimé] / Junghui Chen, Auteur ; Yan-Cheng Jiang, Auteur . - 2011 . - pp. 3345–3355.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3345–3355
Mots-clés : Dynamic Probability Résumé : The repetitive batch operation has a two-dimensional dynamic behavior, including a finite time interval of each batch run in the time domain and infinite repetitions along the batch domain. In this Article, a novel monitoring method that combines dynamic multiway principal component analysis (DMPCA) and hidden segmental semi-Markov models (HSMM) is proposed to resolve the problem caused by the two-dimensional behavior of batch processes. DMPCA utilizes the batch-to-batch dynamic characteristics and eliminates the batch correlation among process variables. HSMM is used to construct the temporal behavior among process variables during each batch run. By constructing a two-dimensional model, the proposed method can generate simple probability monitoring charts and monitor the progress in each batch run. The proposed method has the temporal property of HSMM and the batch-to-batch dynamic characteristics of DMPCA. Its advantages are demonstrated through a simulated fed-batch penicillin cultivation process characterized by fault sources. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101189g Exemplaires
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Titre : Suitable modeling for process flow sheet optimization using the correct economic criterion Type de document : texte imprimé Auteurs : M. Kasas, Auteur ; Z. Kravanja, Auteur ; Z. Novak Pintaric, Auteur Année de publication : 2011 Article en page(s) : pp. 3356–3370 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Optimization Process flow Résumé : In process systems engineering, mathematical models with different economic objective functions, e.g., total cost, profit, net present value, and the internal rate of return, are frequently used for process flow sheet optimization. In financial theory, however, the net present value is the only correct criterion when selecting from among mutually exclusive alternatives, while the others are not totally correct. This paper shows that only those process models with sufficient levels of accuracy are suitable for generating proper optimal designs using the correct economic criterion. An analysis method is proposed for testing the accuracy and adequacy of process flow sheet optimization models, in terms of appropriate trade-offs between invested funds and generated cash flows. This method analyzes the cash flow function vs investment, its derivative, and the differences between optimum solutions obtained by different economic criteria. Suitable process models generate concave monotonically increasing cash flow functions and flat derivative curves, while optimal designs obtained by different economic criteria are substantially different. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101485z
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3356–3370[article] Suitable modeling for process flow sheet optimization using the correct economic criterion [texte imprimé] / M. Kasas, Auteur ; Z. Kravanja, Auteur ; Z. Novak Pintaric, Auteur . - 2011 . - pp. 3356–3370.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3356–3370
Mots-clés : Optimization Process flow Résumé : In process systems engineering, mathematical models with different economic objective functions, e.g., total cost, profit, net present value, and the internal rate of return, are frequently used for process flow sheet optimization. In financial theory, however, the net present value is the only correct criterion when selecting from among mutually exclusive alternatives, while the others are not totally correct. This paper shows that only those process models with sufficient levels of accuracy are suitable for generating proper optimal designs using the correct economic criterion. An analysis method is proposed for testing the accuracy and adequacy of process flow sheet optimization models, in terms of appropriate trade-offs between invested funds and generated cash flows. This method analyzes the cash flow function vs investment, its derivative, and the differences between optimum solutions obtained by different economic criteria. Suitable process models generate concave monotonically increasing cash flow functions and flat derivative curves, while optimal designs obtained by different economic criteria are substantially different. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101485z Exemplaires
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Titre : Multi - objective lot - sizing and scheduling dealing with perishability issues Type de document : texte imprimé Auteurs : Pedro Amorim, Auteur ; Carlos H. Antunes, Auteur ; Bernardo Almada-Lobo, Auteur Année de publication : 2011 Article en page(s) : pp. 3371–3381 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Scheduling Résumé : The recent evidence demonstrating the importance of perishables in terms of store choice and shopping experience makes these products a very interesting topic in many different research areas. Nevertheless, the production planning research has not been paying the necessary attention to the complexities of production systems of such items. The evidence that consumers of perishable goods search for visual and other cues of freshness, such as the printed expiry dates, triggered the development of a multi-objective lot-sizing and scheduling model taking this relevant aspect into account by considering it explicitly as an objective function. A hybrid genetic algorithm based on NSGA-II was developed to allow the decision maker a true choice between different trade-offs from the Pareto front. Computational experiments were based on a case study, reported in the literature, concerning a diary company producing yogurt. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101645h
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3371–3381[article] Multi - objective lot - sizing and scheduling dealing with perishability issues [texte imprimé] / Pedro Amorim, Auteur ; Carlos H. Antunes, Auteur ; Bernardo Almada-Lobo, Auteur . - 2011 . - pp. 3371–3381.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3371–3381
Mots-clés : Scheduling Résumé : The recent evidence demonstrating the importance of perishables in terms of store choice and shopping experience makes these products a very interesting topic in many different research areas. Nevertheless, the production planning research has not been paying the necessary attention to the complexities of production systems of such items. The evidence that consumers of perishable goods search for visual and other cues of freshness, such as the printed expiry dates, triggered the development of a multi-objective lot-sizing and scheduling model taking this relevant aspect into account by considering it explicitly as an objective function. A hybrid genetic algorithm based on NSGA-II was developed to allow the decision maker a true choice between different trade-offs from the Pareto front. Computational experiments were based on a case study, reported in the literature, concerning a diary company producing yogurt. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101645h Exemplaires
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Titre : Control of an isomerization column / reactor process Type de document : texte imprimé Auteurs : William L. Luyben, Auteur Année de publication : 2011 Article en page(s) : pp. 3382-3389 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Reactor Isomerization Résumé : The control of a distillation column with a side reactor is studied for the conversion of n-butane into isobutane for use in the alkylation process. Fresh feed of a mixture of propane, isobutane, n-butane, and isopentane is fed to a distillation column. A vapor sidestream is withdrawn in the stripping section of the column and fed to an isomerization reactor in which some of the n-butane is converted to isobutane. Reactor effluent is fed back into the column in the rectifying section. Isopentane is removed in the bottoms, and moderate-purity isobutane is removed in the distillate. The control of the purity of the isobutane product can be achieved in two alternative ways: manipulating sidestream flow rate to the reactor or manipulating reflux ratio. The latter method is demonstrated to be better because manipulating sidestream flow rate presents potential control problems due to the existence of multiple steady states. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944505
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3382-3389[article] Control of an isomerization column / reactor process [texte imprimé] / William L. Luyben, Auteur . - 2011 . - pp. 3382-3389.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3382-3389
Mots-clés : Reactor Isomerization Résumé : The control of a distillation column with a side reactor is studied for the conversion of n-butane into isobutane for use in the alkylation process. Fresh feed of a mixture of propane, isobutane, n-butane, and isopentane is fed to a distillation column. A vapor sidestream is withdrawn in the stripping section of the column and fed to an isomerization reactor in which some of the n-butane is converted to isobutane. Reactor effluent is fed back into the column in the rectifying section. Isopentane is removed in the bottoms, and moderate-purity isobutane is removed in the distillate. The control of the purity of the isobutane product can be achieved in two alternative ways: manipulating sidestream flow rate to the reactor or manipulating reflux ratio. The latter method is demonstrated to be better because manipulating sidestream flow rate presents potential control problems due to the existence of multiple steady states. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944505 Exemplaires
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Titre : Nonlinear bioprocess monitoring using multiway kernel localized fisher discriminant analysis Type de document : texte imprimé Auteurs : Jie Yu, Auteur Année de publication : 2011 Article en page(s) : pp. 3390–3402 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Bioprocess Résumé : A novel batch bioprocess monitoring approach based on multiway kernel localized Fisher discriminant analysis (MKLFDA) is proposed in this article. For the routine bioprocess operation with some abnormal events, a supervised monitoring method is needed to handle the training data set that includes various types of faulty samples. Because of the inherent process nonlinearity and multimodality among normal and faulty clusters, the traditional multiway Fisher discriminant analysis (MFDA) method becomes inappropriate and unable to effectively detect or classify faulty samples. The newly developed MKLFDA approach, however, combines kernel function with the localized Fisher discriminant analysis so that the “kernel” feature can retain the process nonlinearity while the “localized” characteristic is able to extract the multi-Gaussianity within data clusters. Furthermore, the integrated multiway analysis uses batch-wise unfolding to convert the three-dimensional data set into a two-dimensional matrix that can be fed into the kernel localized Fisher discriminant analysis for fault detection and classification. The proposed MKLFDA approach is applied to three test scenarios in the fed-batch penicillin fermentation process and its batch monitoring performance is compared to that of the conventional MFDA method. The results indicate that the MKLFDA approach performs much better than MFDA method in detecting abnormal operating conditions as well as classifying various types of process faults occurring in fed-batch operation. The MKLFDA approach results in higher fault detection rate and lower false classifications. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1017282
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3390–3402[article] Nonlinear bioprocess monitoring using multiway kernel localized fisher discriminant analysis [texte imprimé] / Jie Yu, Auteur . - 2011 . - pp. 3390–3402.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3390–3402
Mots-clés : Bioprocess Résumé : A novel batch bioprocess monitoring approach based on multiway kernel localized Fisher discriminant analysis (MKLFDA) is proposed in this article. For the routine bioprocess operation with some abnormal events, a supervised monitoring method is needed to handle the training data set that includes various types of faulty samples. Because of the inherent process nonlinearity and multimodality among normal and faulty clusters, the traditional multiway Fisher discriminant analysis (MFDA) method becomes inappropriate and unable to effectively detect or classify faulty samples. The newly developed MKLFDA approach, however, combines kernel function with the localized Fisher discriminant analysis so that the “kernel” feature can retain the process nonlinearity while the “localized” characteristic is able to extract the multi-Gaussianity within data clusters. Furthermore, the integrated multiway analysis uses batch-wise unfolding to convert the three-dimensional data set into a two-dimensional matrix that can be fed into the kernel localized Fisher discriminant analysis for fault detection and classification. The proposed MKLFDA approach is applied to three test scenarios in the fed-batch penicillin fermentation process and its batch monitoring performance is compared to that of the conventional MFDA method. The results indicate that the MKLFDA approach performs much better than MFDA method in detecting abnormal operating conditions as well as classifying various types of process faults occurring in fed-batch operation. The MKLFDA approach results in higher fault detection rate and lower false classifications. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1017282 Exemplaires
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Titre : A method of online safety assessment for industrial process operations based on hopf bifurcation analysis Type de document : texte imprimé Auteurs : Lubin Ye, Auteur ; Zhengshun Fei, Auteur ; Jun Liang, Auteur Année de publication : 2011 Article en page(s) : pp. 3403–3414 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Industrial process Bifurcation analysis Résumé : This paper proposes an approach of online safety assessment for industrial process operations. The core idea is to apply the Hopf bifurcation analysis of nonlinear systems in safety assessment. Herein, the Hopf bifurcation equations are used to characterize the critical stability boundary or manifold of the system, which is taken as the safety limit. Then, a safety index (SI) is constructed to denote the integrated exponential distances between each parameter and their bifurcation points. In the online implementation, the parameters are estimated by the extended Kalman filter (EKF), and the Hopf bifurcation points are generated by solving the nonlinear bifurcation equations. Afterward, the value of the SI can be online calculated. The introduced approach was then applied to a simulated gas phase polyethylene reactor process, in which the efficiency of the proposed method was verified in indicating the distance to the potential unsafe oscillation and in the early identification of potential threats. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1018854
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3403–3414[article] A method of online safety assessment for industrial process operations based on hopf bifurcation analysis [texte imprimé] / Lubin Ye, Auteur ; Zhengshun Fei, Auteur ; Jun Liang, Auteur . - 2011 . - pp. 3403–3414.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3403–3414
Mots-clés : Industrial process Bifurcation analysis Résumé : This paper proposes an approach of online safety assessment for industrial process operations. The core idea is to apply the Hopf bifurcation analysis of nonlinear systems in safety assessment. Herein, the Hopf bifurcation equations are used to characterize the critical stability boundary or manifold of the system, which is taken as the safety limit. Then, a safety index (SI) is constructed to denote the integrated exponential distances between each parameter and their bifurcation points. In the online implementation, the parameters are estimated by the extended Kalman filter (EKF), and the Hopf bifurcation points are generated by solving the nonlinear bifurcation equations. Afterward, the value of the SI can be online calculated. The introduced approach was then applied to a simulated gas phase polyethylene reactor process, in which the efficiency of the proposed method was verified in indicating the distance to the potential unsafe oscillation and in the early identification of potential threats. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1018854 Exemplaires
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Titre : Analysis and tuning of RTD - A controllers Type de document : texte imprimé Auteurs : Antonius Yudi Sendjaja, Auteur ; Zhen Fu Ng, Auteur ; Si Si How, Auteur Année de publication : 2011 Article en page(s) : pp. 3415-3425 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Residence time distribution Résumé : RTD-A controller has recently been proposed as an alternative to the proportional-integral-derivative (PID) controller for control of single-input single-output systems. The RTD-A controller maintains the simplicity like the PID controller, has predictive capabilities like model predictive controller, and allows easier tuning of the controller parameters to achieve desired closed-loop performance. The available tuning rule for RTD-A controllers are aggressive, and their application to practical problems can be difficult. In this paper, a block diagram representation of the RTD-A controller is developed. It is shown that the RTD-A controller can be viewed as a generalized analytical predictor augmented with noise and set point filters. On the basis of the block diagram representation, semianalytical tuning rules are proposed for the RTD-A algorithm. It is shown that the RTD-A controller tuned using the proposed rule provides reasonable performance for a wide class of processes including inverse response and delay-dominant processes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944508
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3415-3425[article] Analysis and tuning of RTD - A controllers [texte imprimé] / Antonius Yudi Sendjaja, Auteur ; Zhen Fu Ng, Auteur ; Si Si How, Auteur . - 2011 . - pp. 3415-3425.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3415-3425
Mots-clés : Residence time distribution Résumé : RTD-A controller has recently been proposed as an alternative to the proportional-integral-derivative (PID) controller for control of single-input single-output systems. The RTD-A controller maintains the simplicity like the PID controller, has predictive capabilities like model predictive controller, and allows easier tuning of the controller parameters to achieve desired closed-loop performance. The available tuning rule for RTD-A controllers are aggressive, and their application to practical problems can be difficult. In this paper, a block diagram representation of the RTD-A controller is developed. It is shown that the RTD-A controller can be viewed as a generalized analytical predictor augmented with noise and set point filters. On the basis of the block diagram representation, semianalytical tuning rules are proposed for the RTD-A algorithm. It is shown that the RTD-A controller tuned using the proposed rule provides reasonable performance for a wide class of processes including inverse response and delay-dominant processes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944508 Exemplaires
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Titre : Modified duplex PSA.1. sharp separation and process intensification for CO2-N2-13X zeolite system Type de document : texte imprimé Auteurs : S. V. Sivakumar, Auteur ; D. P. Rao, Auteur Année de publication : 2011 Article en page(s) : pp. 3426-3436 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Zeolite Carbon dioxide Résumé : A modified duplex PSA has been proposed, which could yield sharp separation and has the potential for process intensification. The performances for the original and the modified duplex PSA have been evaluated for two types of systems: the CO2-N2-13X zeolite with single component adsorption and the N2-O2-5A zeolite with competing adsorption. Part 1 of the companion papers presents the simulation studies on the separation of the CO2-N2 mixture. The purities of both products were in excess of 99 mol % with the modified duplex PSA against 78 mol% CO2 and 95 mol% N2 with the original duplex PSA for the same conditions. The bed sizes and energy requirements for the modified duplex PSA were one-half of those for the original duplex PSA. Part 2 presents studies on the separation of the N2-O2 mixture. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944509
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3426-3436[article] Modified duplex PSA.1. sharp separation and process intensification for CO2-N2-13X zeolite system [texte imprimé] / S. V. Sivakumar, Auteur ; D. P. Rao, Auteur . - 2011 . - pp. 3426-3436.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3426-3436
Mots-clés : Zeolite Carbon dioxide Résumé : A modified duplex PSA has been proposed, which could yield sharp separation and has the potential for process intensification. The performances for the original and the modified duplex PSA have been evaluated for two types of systems: the CO2-N2-13X zeolite with single component adsorption and the N2-O2-5A zeolite with competing adsorption. Part 1 of the companion papers presents the simulation studies on the separation of the CO2-N2 mixture. The purities of both products were in excess of 99 mol % with the modified duplex PSA against 78 mol% CO2 and 95 mol% N2 with the original duplex PSA for the same conditions. The bed sizes and energy requirements for the modified duplex PSA were one-half of those for the original duplex PSA. Part 2 presents studies on the separation of the N2-O2 mixture. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944509 Exemplaires
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Titre : Modified duplex PSA. 2. sharp separation and process intensification for N2-O2-5A zeolite system Type de document : texte imprimé Auteurs : S. V. Sivakumar, Auteur ; D. P. Rao, Auteur Année de publication : 2011 Article en page(s) : pp. 3437-3445 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Zeolite Résumé : We present the simulation studies carried on separation of the N2-O2 mixture with the original and modified duplex PSA. The purities of products were in excess of 99 mol % with the modified duplex PSA, whereas the original duplex PSA yielded product purities of 72 mol %. For both product purities of 95 mol %, the bed size and energy requirements with the modified duplex PSA were less by 10 and 2.5 times respectively compared to the conventional PSA and were less by an order of magnitude compared to those with original duplex PSA. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944510
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3437-3445[article] Modified duplex PSA. 2. sharp separation and process intensification for N2-O2-5A zeolite system [texte imprimé] / S. V. Sivakumar, Auteur ; D. P. Rao, Auteur . - 2011 . - pp. 3437-3445.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3437-3445
Mots-clés : Zeolite Résumé : We present the simulation studies carried on separation of the N2-O2 mixture with the original and modified duplex PSA. The purities of products were in excess of 99 mol % with the modified duplex PSA, whereas the original duplex PSA yielded product purities of 72 mol %. For both product purities of 95 mol %, the bed size and energy requirements with the modified duplex PSA were less by 10 and 2.5 times respectively compared to the conventional PSA and were less by an order of magnitude compared to those with original duplex PSA. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944510 Exemplaires
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Titre : Banana peel applied to the solid phase extraction of copper and lead from river water : preconcentration of metal ions with a fruit waste Type de document : texte imprimé Auteurs : Renata S. D. Castro, Auteur ; Laercio Caetano, Auteur ; Guilherme Ferreira, Auteur Année de publication : 2011 Article en page(s) : pp. 3446–3451 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Banana peel extract lead copper ions from water Résumé : This article reports on an investigation into the ability of minced banana peel to extract lead and copper ions from water and the parameters involved in this process. The kinetics of copper and lead uptake reached equilibrium in 10 min and the extraction of metals ions was favorable above pH 3. The medium was characterized by FTIR, which showed absorption bands of carboxylic and amine groups at 1730 and 889 cm1, respectively. The adsorption isotherm fitted by Langmuir’s model showed maximum adsorption capacities of 0.33 and 0.20 mmol g−1 (or 20.97 and 41.44 mg g−1) for Cu(II) and Pb(II), respectively. Minced banana peel was applied in the preconcentration system and showed approximately 20-fold enrichment factor and the column was reused for 11 cycles without loss in the percentage of recovery. The proposed method was applied in the determination of Cu(II) and Pb(II) in a sample of raw river water and was validated by comparison with a standard reference material. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101499e
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3446–3451[article] Banana peel applied to the solid phase extraction of copper and lead from river water : preconcentration of metal ions with a fruit waste [texte imprimé] / Renata S. D. Castro, Auteur ; Laercio Caetano, Auteur ; Guilherme Ferreira, Auteur . - 2011 . - pp. 3446–3451.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3446–3451
Mots-clés : Banana peel extract lead copper ions from water Résumé : This article reports on an investigation into the ability of minced banana peel to extract lead and copper ions from water and the parameters involved in this process. The kinetics of copper and lead uptake reached equilibrium in 10 min and the extraction of metals ions was favorable above pH 3. The medium was characterized by FTIR, which showed absorption bands of carboxylic and amine groups at 1730 and 889 cm1, respectively. The adsorption isotherm fitted by Langmuir’s model showed maximum adsorption capacities of 0.33 and 0.20 mmol g−1 (or 20.97 and 41.44 mg g−1) for Cu(II) and Pb(II), respectively. Minced banana peel was applied in the preconcentration system and showed approximately 20-fold enrichment factor and the column was reused for 11 cycles without loss in the percentage of recovery. The proposed method was applied in the determination of Cu(II) and Pb(II) in a sample of raw river water and was validated by comparison with a standard reference material. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101499e Exemplaires
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Titre : Understanding the physical absorption of CO2 in ionic liquids using the COSMO-RS method Type de document : texte imprimé Auteurs : José Palomar, Auteur ; Maria Gonzalez-Miquel, Auteur ; Alicia Polo, Auteur Année de publication : 2011 Article en page(s) : pp. 3452–3463 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Physical absorption CO2 Ionic liquids Résumé : The quantum chemical Conductor-like Screening Model for Real Solvents (COSMO-RS) method was evaluated as a theoretical framework to computationally investigate the application of room temperature ionic liquids (ILs) in absorptive technologies for capturing CO2 from power plant emissions to efficiently reduce both experimental efforts and time consumption. First, different molecular models to simulate ILs and computational methods in geometry calculations were investigated to optimize the COSMO-RS capability to predict Henry’s Law coefficients using a demanding solubility sample test with 35 gaseous solute-IL systems and 20 CO2−IL systems. The simulation results were in good agreement with experimental data, indicating that using an ion-pair molecular model optimized in a gas-phase environment allows a finer COSMO-RS description of the IL structure influence on the CO2 and other solutes solubilities. Moreover, the COSMO-RS methodology was used for the first time to achieve a deeper insight into the behavior of the solubility of CO2 in ILs from a molecular point of view. For this purpose, further analyses of the energetic intermolecular interactions between CO2 and ILs were performed by COSMO-RS, revealing that the van der Waals forces associated with the solute in the liquid phase determine the absorption capacity of CO2 in ILs, which is measured in terms of Henry’s Law coefficients. These findings were finally driven by a rational screening over 170 ILs with COSMO-RS to design new ILs that enhance CO2 capture by physical absorption. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101572m
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3452–3463[article] Understanding the physical absorption of CO2 in ionic liquids using the COSMO-RS method [texte imprimé] / José Palomar, Auteur ; Maria Gonzalez-Miquel, Auteur ; Alicia Polo, Auteur . - 2011 . - pp. 3452–3463.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3452–3463
Mots-clés : Physical absorption CO2 Ionic liquids Résumé : The quantum chemical Conductor-like Screening Model for Real Solvents (COSMO-RS) method was evaluated as a theoretical framework to computationally investigate the application of room temperature ionic liquids (ILs) in absorptive technologies for capturing CO2 from power plant emissions to efficiently reduce both experimental efforts and time consumption. First, different molecular models to simulate ILs and computational methods in geometry calculations were investigated to optimize the COSMO-RS capability to predict Henry’s Law coefficients using a demanding solubility sample test with 35 gaseous solute-IL systems and 20 CO2−IL systems. The simulation results were in good agreement with experimental data, indicating that using an ion-pair molecular model optimized in a gas-phase environment allows a finer COSMO-RS description of the IL structure influence on the CO2 and other solutes solubilities. Moreover, the COSMO-RS methodology was used for the first time to achieve a deeper insight into the behavior of the solubility of CO2 in ILs from a molecular point of view. For this purpose, further analyses of the energetic intermolecular interactions between CO2 and ILs were performed by COSMO-RS, revealing that the van der Waals forces associated with the solute in the liquid phase determine the absorption capacity of CO2 in ILs, which is measured in terms of Henry’s Law coefficients. These findings were finally driven by a rational screening over 170 ILs with COSMO-RS to design new ILs that enhance CO2 capture by physical absorption. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101572m Exemplaires
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Titre : Agglomeration process modeling based on a PDE approximation of the safronov agglomeration equation Type de document : texte imprimé Auteurs : Andrey V. Bekker, Auteur ; Iztok Livk, Auteur Année de publication : 2011 Article en page(s) : pp. 3464–3474 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Agglomeration process Résumé : A one-dimensional dynamic partial differential equation (PDE) agglomeration model is derived based on the continuous Safronov agglomeration equation. A regularized PDE agglomeration model, represented by a set of convection−reaction−diffusion PDEs, can be solved within a standard adaptive-mesh implicit numerical framework that does not require additional quadrature assumptions to evaluate the aggregation integral. The PDE agglomeration model is solved numerically using a general Newton’s-method-based implicit Galerkin finite-element algorithm. The applied algorithm uses an automatic Gear-type time step and nonuniform adaptive-mesh strategies, which aids solution convergence. A numerical solution of the model for an agglomeration degree of 99.9% closely matches an asymptotic analytic solution of the original Safronov equation, which confirms the accuracy of the numerical procedure used. It is also shown that the number density function predicted by the new PDE agglomeration model satisfactorily agrees with the analytic solution of the Smoluchowski agglomeration equation. For small particle sizes and first and zeroth full moments, the two models give similar solutions. However, for larger particle sizes and the second full moment, the difference between the two models increases with increasing degree of agglomeration. Industrially important gibbsite agglomeration is used as a case study to demonstrate the application of the new numerical approach for agglomeration modeling. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101933r
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3464–3474[article] Agglomeration process modeling based on a PDE approximation of the safronov agglomeration equation [texte imprimé] / Andrey V. Bekker, Auteur ; Iztok Livk, Auteur . - 2011 . - pp. 3464–3474.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3464–3474
Mots-clés : Agglomeration process Résumé : A one-dimensional dynamic partial differential equation (PDE) agglomeration model is derived based on the continuous Safronov agglomeration equation. A regularized PDE agglomeration model, represented by a set of convection−reaction−diffusion PDEs, can be solved within a standard adaptive-mesh implicit numerical framework that does not require additional quadrature assumptions to evaluate the aggregation integral. The PDE agglomeration model is solved numerically using a general Newton’s-method-based implicit Galerkin finite-element algorithm. The applied algorithm uses an automatic Gear-type time step and nonuniform adaptive-mesh strategies, which aids solution convergence. A numerical solution of the model for an agglomeration degree of 99.9% closely matches an asymptotic analytic solution of the original Safronov equation, which confirms the accuracy of the numerical procedure used. It is also shown that the number density function predicted by the new PDE agglomeration model satisfactorily agrees with the analytic solution of the Smoluchowski agglomeration equation. For small particle sizes and first and zeroth full moments, the two models give similar solutions. However, for larger particle sizes and the second full moment, the difference between the two models increases with increasing degree of agglomeration. Industrially important gibbsite agglomeration is used as a case study to demonstrate the application of the new numerical approach for agglomeration modeling. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101933r Exemplaires
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Titre : Effect of supersaturation on the morphology of coated surface in coating by solution crystallization Type de document : texte imprimé Auteurs : Jae-Wook Jung, Auteur ; Kwang-Joo Kim, Auteur Année de publication : 2011 Article en page(s) : pp. 3475-3482 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Solution crystallization Morphology Supersaturation Résumé : HMX (cyclotetramethylene tetranitramine) was coated with NTO (3-nitro-1,2,4-triazole-5-one) by solution crystallization. Two-step coating crystallization was investigated to enhance coating morphology. The first coating process using HMX seed and the second coating process using HMX coated with NTO obtained from the first process were compared in terms of coating shape, coating surface, nucleation rate, metastable zone width, and interfacial energy. The objective of this study was to examine how operating conditions affected the surface morphology by coating crystallization. The parameters such as type of seed, concentration, and cooling rate were used in the crystallization process. Finally, the second coating process was found to achieve compact and uniform surfaces of NTO crystals coated on the HMX surface. It was found that higher supersaturation enhances cluster aggregation, which results in uniform coating on the HMX surface. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944514
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3475-3482[article] Effect of supersaturation on the morphology of coated surface in coating by solution crystallization [texte imprimé] / Jae-Wook Jung, Auteur ; Kwang-Joo Kim, Auteur . - 2011 . - pp. 3475-3482.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3475-3482
Mots-clés : Solution crystallization Morphology Supersaturation Résumé : HMX (cyclotetramethylene tetranitramine) was coated with NTO (3-nitro-1,2,4-triazole-5-one) by solution crystallization. Two-step coating crystallization was investigated to enhance coating morphology. The first coating process using HMX seed and the second coating process using HMX coated with NTO obtained from the first process were compared in terms of coating shape, coating surface, nucleation rate, metastable zone width, and interfacial energy. The objective of this study was to examine how operating conditions affected the surface morphology by coating crystallization. The parameters such as type of seed, concentration, and cooling rate were used in the crystallization process. Finally, the second coating process was found to achieve compact and uniform surfaces of NTO crystals coated on the HMX surface. It was found that higher supersaturation enhances cluster aggregation, which results in uniform coating on the HMX surface. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944514 Exemplaires
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Titre : Phase transformation of guanosine 5-monophosphate in continuous couette—taylor crystallizer : experiments and numerical modeling for kinetics Type de document : texte imprimé Auteurs : Anh-Tuan Nguyen, Auteur ; Jong-Min Kim, Auteur ; Sang-Mok Chang, Auteur Année de publication : 2011 Article en page(s) : pp. 3483–3493 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetics Numerical simulation Crystallizer Phase transformation Résumé : The phase transformation of guanosine 5-monophosphate (GMP) during drowning-out crystallization in a continuous Couette-Taylor (CT) crystallizer was studied experimentally and numerically. At a steady state, the phase transformation of the amorphous GMP into hydrate crystals was monitored along the axial direction of the CT crystallizer when varying the crystallization conditions, including the rotation speed of the inner cylinder of the crystallizer and the feed concentration. As a result, the phase transformation was significantly facilitated when increasing the rotation speed, due to the enhanced dissolution of the amorphous GMP, as well as the growth of the hydrate crystals. For the numerical modeling, simple material balances were derived for three kinds of GMP: the amorphous GMP, hydrate crystals, and GMP concentration in the solution, under the assumption of plug flow behavior for the fluid motion in the CT crystallizer. The simple model predictions matched well with the experimental profiles for the three kinds of GMP along the axial direction of the crystallizer, allowing estimates for the kinetics of the phase transformation, including the mass transfer coefficients for dissolution and growth. According to the model predictions, the rates of amorphous GMP dissolution and hydrate crystal growth were both competitive to control the phase transformation in the CT crystallizer, and about 10 times higher than those in a stirred tank crystallizer. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944515
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3483–3493[article] Phase transformation of guanosine 5-monophosphate in continuous couette—taylor crystallizer : experiments and numerical modeling for kinetics [texte imprimé] / Anh-Tuan Nguyen, Auteur ; Jong-Min Kim, Auteur ; Sang-Mok Chang, Auteur . - 2011 . - pp. 3483–3493.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3483–3493
Mots-clés : Kinetics Numerical simulation Crystallizer Phase transformation Résumé : The phase transformation of guanosine 5-monophosphate (GMP) during drowning-out crystallization in a continuous Couette-Taylor (CT) crystallizer was studied experimentally and numerically. At a steady state, the phase transformation of the amorphous GMP into hydrate crystals was monitored along the axial direction of the CT crystallizer when varying the crystallization conditions, including the rotation speed of the inner cylinder of the crystallizer and the feed concentration. As a result, the phase transformation was significantly facilitated when increasing the rotation speed, due to the enhanced dissolution of the amorphous GMP, as well as the growth of the hydrate crystals. For the numerical modeling, simple material balances were derived for three kinds of GMP: the amorphous GMP, hydrate crystals, and GMP concentration in the solution, under the assumption of plug flow behavior for the fluid motion in the CT crystallizer. The simple model predictions matched well with the experimental profiles for the three kinds of GMP along the axial direction of the crystallizer, allowing estimates for the kinetics of the phase transformation, including the mass transfer coefficients for dissolution and growth. According to the model predictions, the rates of amorphous GMP dissolution and hydrate crystal growth were both competitive to control the phase transformation in the CT crystallizer, and about 10 times higher than those in a stirred tank crystallizer. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944515 Exemplaires
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Titre : Coupling Ion Exchange and Biosorption for Copper(II) Removal From Wastewaters Type de document : texte imprimé Auteurs : Anna Gorka, Auteur ; Justyna Zamorska, Auteur ; Dorota Antos, Auteur Année de publication : 2011 Article en page(s) : pp. 3494–3502 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ion exchange Removal wastewaters Résumé : A coupled process of ion exchange and biosorption for recovery of copper(II) from wastewater has been proposed. In this process a cation exchanger has been used as a carrier for the biofilm formation. Two different types of microorganisms capable for copper biosorption have been selected for immobilization, i.e, effective microorganisms and activated sludge microorganisms. As a regenerating agent solutions of sodium bicarbonate with aqueous ammonia as an additive have been used, which allowed operating the column under mild pH conditions. The activity of biofilm was preserved after the cyclic process of ion exchange and regeneration. The effect of biofilm on the mass transfer kinetics and the ion exchange equilibrium was quantified by comparing the efficiency of ion exchange on the fresh bed and that covered by biofilm. The linear driving force model was used for simulations of the process dynamics. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101019s
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3494–3502[article] Coupling Ion Exchange and Biosorption for Copper(II) Removal From Wastewaters [texte imprimé] / Anna Gorka, Auteur ; Justyna Zamorska, Auteur ; Dorota Antos, Auteur . - 2011 . - pp. 3494–3502.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3494–3502
Mots-clés : Ion exchange Removal wastewaters Résumé : A coupled process of ion exchange and biosorption for recovery of copper(II) from wastewater has been proposed. In this process a cation exchanger has been used as a carrier for the biofilm formation. Two different types of microorganisms capable for copper biosorption have been selected for immobilization, i.e, effective microorganisms and activated sludge microorganisms. As a regenerating agent solutions of sodium bicarbonate with aqueous ammonia as an additive have been used, which allowed operating the column under mild pH conditions. The activity of biofilm was preserved after the cyclic process of ion exchange and regeneration. The effect of biofilm on the mass transfer kinetics and the ion exchange equilibrium was quantified by comparing the efficiency of ion exchange on the fresh bed and that covered by biofilm. The linear driving force model was used for simulations of the process dynamics. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101019s Exemplaires
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Titre : Modeling pH and solubilities in aqueous multisolute amino acid solutions Type de document : texte imprimé Auteurs : Jan-Bernd Grosse Daldrup, Auteur ; Christoph Held, Auteur ; Gabriele Sadowski, Auteur Année de publication : 2011 Article en page(s) : pp. 3503–3509 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Amino acids Aqueous multisolute Résumé : The solubility of amino acids is highly depending on the prevailing pH value. However, this dependency is neglected in the state-of-the-art modeling of solubilities in multisolute solutions. In order to describe the pH-dependency of the solubilities, the PC-SAFT model is applied to aqueous solutions containing two amino acids accounting for their dissociation/association equilibria. This approach is applied to four ternary mixtures with pronounced pH-dependent solubility behavior allowing for a good description of experimental amino acid solubilities depending on temperature, cosolute concentration, and pH value. The systems considered within this work each contain two amino acids which show big differences in pI, i.e., l-glutamic acid or l/dl-aspartic acid on the one hand and glycine or l-serine on the other hand, respectively. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1010367
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3503–3509[article] Modeling pH and solubilities in aqueous multisolute amino acid solutions [texte imprimé] / Jan-Bernd Grosse Daldrup, Auteur ; Christoph Held, Auteur ; Gabriele Sadowski, Auteur . - 2011 . - pp. 3503–3509.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3503–3509
Mots-clés : Amino acids Aqueous multisolute Résumé : The solubility of amino acids is highly depending on the prevailing pH value. However, this dependency is neglected in the state-of-the-art modeling of solubilities in multisolute solutions. In order to describe the pH-dependency of the solubilities, the PC-SAFT model is applied to aqueous solutions containing two amino acids accounting for their dissociation/association equilibria. This approach is applied to four ternary mixtures with pronounced pH-dependent solubility behavior allowing for a good description of experimental amino acid solubilities depending on temperature, cosolute concentration, and pH value. The systems considered within this work each contain two amino acids which show big differences in pI, i.e., l-glutamic acid or l/dl-aspartic acid on the one hand and glycine or l-serine on the other hand, respectively. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1010367 Exemplaires
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Titre : New impeller for viscous fermentation : power input and mass transfer coefficient correlations Type de document : texte imprimé Auteurs : Yun Lin, Auteur ; Zisheng Zhang, Auteur ; Jules Thibault, Auteur Année de publication : 2011 Article en page(s) : pp. 3510-3516 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Correlation analysis Mass transfer coefficient Fermentation Agitator Résumé : To mix viscous fermentation broths more efficiently, a new close-clearance impeller, the rotational reciprocating plate impeller (RRPI), was designed to partly mimic the axial reciprocating plate impeller (ARPI). Akin to the axial movement of a reciprocating plate impeller, this new RRPI rotates back and forth driven by a three-arm linkage system. Its power consumption and overall mass transfer coefficient (KLa) were determined in a 22 L laboratory scale bioreactor using model fluids of different viscosities. Results obtained with this new impeller were compared to those of a triple Rushton impeller (TRI) and an ARPI. In water, results were the same as those of the TRI. However, the ARPI gave significantly lower KLa than the other two impellers for the same power input per unit volume. In highly viscous non-Newtonian carboxymethyl cellulose (CMC) solutions, the new impeller showed similar performance as the ARPI, whereas the TRI was not able to provide acceptable mixing due to the presence of stagnant zones. Therefore, this new impeller proves to be a suitable alternative to existing impellers for use in fermentations having rheologically evolving broth. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944518
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3510-3516[article] New impeller for viscous fermentation : power input and mass transfer coefficient correlations [texte imprimé] / Yun Lin, Auteur ; Zisheng Zhang, Auteur ; Jules Thibault, Auteur . - 2011 . - pp. 3510-3516.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3510-3516
Mots-clés : Correlation analysis Mass transfer coefficient Fermentation Agitator Résumé : To mix viscous fermentation broths more efficiently, a new close-clearance impeller, the rotational reciprocating plate impeller (RRPI), was designed to partly mimic the axial reciprocating plate impeller (ARPI). Akin to the axial movement of a reciprocating plate impeller, this new RRPI rotates back and forth driven by a three-arm linkage system. Its power consumption and overall mass transfer coefficient (KLa) were determined in a 22 L laboratory scale bioreactor using model fluids of different viscosities. Results obtained with this new impeller were compared to those of a triple Rushton impeller (TRI) and an ARPI. In water, results were the same as those of the TRI. However, the ARPI gave significantly lower KLa than the other two impellers for the same power input per unit volume. In highly viscous non-Newtonian carboxymethyl cellulose (CMC) solutions, the new impeller showed similar performance as the ARPI, whereas the TRI was not able to provide acceptable mixing due to the presence of stagnant zones. Therefore, this new impeller proves to be a suitable alternative to existing impellers for use in fermentations having rheologically evolving broth. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944518 Exemplaires
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Titre : Commercial operation test and performance analysis of a 200 MWe super - high - pressure circulating fluidized bed boiler Type de document : texte imprimé Auteurs : Y. K. Sun, Auteur ; Q. G. Lu, Auteur ; S. L. Bao, Auteur Année de publication : 2011 Article en page(s) : pp. 3517-3523 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Fluidization Circulating fluidized bed Fluidized boiler Résumé : A 200 MWe circulating fluidized bed (CFB) boiler with three cyclone separators was built in Inner Mongolia in China, and tests were carried out with the coal combustion process. The objective of this research is to investigate the effect of primary (secondary) air flow rate on the combustion process and the effect of multicyclone separator arrangement on solids circulation characteristics. Temperature and pressure drops at different positions in the boiler chamber and cyclone separator diplegs were measured. On the basis of the measured temperature and pressure, heat flux and solids void fraction distribution in the chamber are derived and analyzed. The profiles of temperature, pressure, heat flux, and solids void fraction along the height of the CFB boiler chamber and in the dipleg of cyclone separators at different operation conditions are given and discussed. The secondary air penetration depth in the dense area was tested at different operation conditions, and the effect of secondary air on the combustion process has been investigated. The preliminary test results indicate that the solid distribution in the three parallel cyclone separators is nonuniform and future research is necessary to optimize the arrangement of multicyclone separators for large scale CFB boilers. Key issues on superhigh pressure CFB boiler design, scaling up of CFB boilers, and further work on computational fluid dynamics (CFD) simulation for hydrodynamic behavior in the CFB boiler and cyclone separators are given at the end of this paper. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944519
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3517-3523[article] Commercial operation test and performance analysis of a 200 MWe super - high - pressure circulating fluidized bed boiler [texte imprimé] / Y. K. Sun, Auteur ; Q. G. Lu, Auteur ; S. L. Bao, Auteur . - 2011 . - pp. 3517-3523.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3517-3523
Mots-clés : Fluidization Circulating fluidized bed Fluidized boiler Résumé : A 200 MWe circulating fluidized bed (CFB) boiler with three cyclone separators was built in Inner Mongolia in China, and tests were carried out with the coal combustion process. The objective of this research is to investigate the effect of primary (secondary) air flow rate on the combustion process and the effect of multicyclone separator arrangement on solids circulation characteristics. Temperature and pressure drops at different positions in the boiler chamber and cyclone separator diplegs were measured. On the basis of the measured temperature and pressure, heat flux and solids void fraction distribution in the chamber are derived and analyzed. The profiles of temperature, pressure, heat flux, and solids void fraction along the height of the CFB boiler chamber and in the dipleg of cyclone separators at different operation conditions are given and discussed. The secondary air penetration depth in the dense area was tested at different operation conditions, and the effect of secondary air on the combustion process has been investigated. The preliminary test results indicate that the solid distribution in the three parallel cyclone separators is nonuniform and future research is necessary to optimize the arrangement of multicyclone separators for large scale CFB boilers. Key issues on superhigh pressure CFB boiler design, scaling up of CFB boilers, and further work on computational fluid dynamics (CFD) simulation for hydrodynamic behavior in the CFB boiler and cyclone separators are given at the end of this paper. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944519 Exemplaires
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Titre : Rheological behavior of cellulose fiber suspensions : application to paper - making processing Type de document : texte imprimé Auteurs : Didier Chaussy, Auteur ; Celine Martin, Auteur ; Jean-Claude Roux, Auteur Année de publication : 2011 Article en page(s) : pp. 3524–3533 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Cellulose fiber Résumé : The refining operation of cellulose fibrous suspensions results in fibrillation, hydration, and shortening of fibers. To characterize the viscous behavior of such a suspension during processing, rheological properties of bleached softwood fibers are studied by considering a semi-industrial disk refiner as a parallel plate rheometer. The rheological behavior of fiber suspension is quantified and modeled using a modified Carreau−Yasuda equation. This model does not show discontinuities and enables the description of the pulp suspension behavior for the entire domain of shear rates (up to 2.1 × 106 s−1). It points out a Newtonian behavior or a combination of a Newtonian followed by a shear thinning behavior after a limiting shear rate. Moreover, the measured apparent viscosity of the fiber suspension in the gap clearance is about 100 times higher than the viscosity of individualized fibers suspension. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101591s
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3524–3533[article] Rheological behavior of cellulose fiber suspensions : application to paper - making processing [texte imprimé] / Didier Chaussy, Auteur ; Celine Martin, Auteur ; Jean-Claude Roux, Auteur . - 2011 . - pp. 3524–3533.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3524–3533
Mots-clés : Cellulose fiber Résumé : The refining operation of cellulose fibrous suspensions results in fibrillation, hydration, and shortening of fibers. To characterize the viscous behavior of such a suspension during processing, rheological properties of bleached softwood fibers are studied by considering a semi-industrial disk refiner as a parallel plate rheometer. The rheological behavior of fiber suspension is quantified and modeled using a modified Carreau−Yasuda equation. This model does not show discontinuities and enables the description of the pulp suspension behavior for the entire domain of shear rates (up to 2.1 × 106 s−1). It points out a Newtonian behavior or a combination of a Newtonian followed by a shear thinning behavior after a limiting shear rate. Moreover, the measured apparent viscosity of the fiber suspension in the gap clearance is about 100 times higher than the viscosity of individualized fibers suspension. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101591s Exemplaires
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Titre : Synthesis of Fe3O4 nanoparticles using controlled ammonia vapor diffusion under ultrasonic irradiation Type de document : texte imprimé Auteurs : Zunli Mo, Auteur ; Chun Zhang, Auteur ; Ruibin Guo, Auteur Année de publication : 2011 Article en page(s) : pp. 3534–3539 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ammonia vapor Ultrasonic irradiation Résumé : Fe3O4 nanoparticles were synthesized for the first time via an ammonia vapor diffusion process under ultrasonic irradiation. The possible ultrasound mechanism and the process of ammonia diffusion and reaction has been deduced. Influences of experiment parameters such as reaction time, temperature on the morphology, and size of products were also investigated in detail. Morphology and magnetic properties of products were carefully studied by Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), Scanning electron microscopes (SEM), and vibrating sample magnetometer (VSM). The synthesized Fe3O4 nanoparticles possess superparamagnetic properties at room temperature, and the saturation magnetization is 70.5 emu/g. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101683x
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3534–3539[article] Synthesis of Fe3O4 nanoparticles using controlled ammonia vapor diffusion under ultrasonic irradiation [texte imprimé] / Zunli Mo, Auteur ; Chun Zhang, Auteur ; Ruibin Guo, Auteur . - 2011 . - pp. 3534–3539.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3534–3539
Mots-clés : Ammonia vapor Ultrasonic irradiation Résumé : Fe3O4 nanoparticles were synthesized for the first time via an ammonia vapor diffusion process under ultrasonic irradiation. The possible ultrasound mechanism and the process of ammonia diffusion and reaction has been deduced. Influences of experiment parameters such as reaction time, temperature on the morphology, and size of products were also investigated in detail. Morphology and magnetic properties of products were carefully studied by Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), Scanning electron microscopes (SEM), and vibrating sample magnetometer (VSM). The synthesized Fe3O4 nanoparticles possess superparamagnetic properties at room temperature, and the saturation magnetization is 70.5 emu/g. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101683x Exemplaires
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Titre : Hydrothermal synthesis of CuO nanoparticles : study on effects of operational conditions on yield, purity, and size of the nanoparticles Type de document : texte imprimé Auteurs : M. Outokesh, Auteur ; M. Hosseinpour, Auteur ; S. J. Ahmadi, Auteur Année de publication : 2011 Article en page(s) : pp. 3540–3554 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydrothermal Nanoparticles Résumé : Hydrothermal synthesis of CuO nanoparticles under near-critical and supercritical conditions was investigated from two different standpoints in the current study. The first standpoint was optimization of “yield”, “purity”, and “size of the nanoparticles” that were optimized at T = 500 °C, time = 2 h, [Cu(NO3)2] = 0.1 mol dm−3, and pH 3. This was achieved by undertaking an orthogonal experiment design methodology and performing different instrumental analyses, such as X-ray diffractometry, inductively coupled plasma spectrometry, and transmission electron microscopy, along with treatment of the data by analysis of variance (ANOVA). The second goal of the study was elucidation of the mechanisms of effects of operational conditions (e.g., temperature) on the above-mentioned target parameters, through application of the appropriate mechanisms of formation of nanoparticles. Nanoparticles are suggested to form initially in the liquid phase as Cu(OH)2, which are later transformed to Cu2(OH)3NO3, through which CuO product is obtained. Decomposition of nitric acid also plays role in this mechanism. Fabricated nanoparticles are effective catalysts for the synthesis of benzoheterocycle compounds in the pharmaceutical industries. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1017089
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3540–3554[article] Hydrothermal synthesis of CuO nanoparticles : study on effects of operational conditions on yield, purity, and size of the nanoparticles [texte imprimé] / M. Outokesh, Auteur ; M. Hosseinpour, Auteur ; S. J. Ahmadi, Auteur . - 2011 . - pp. 3540–3554.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3540–3554
Mots-clés : Hydrothermal Nanoparticles Résumé : Hydrothermal synthesis of CuO nanoparticles under near-critical and supercritical conditions was investigated from two different standpoints in the current study. The first standpoint was optimization of “yield”, “purity”, and “size of the nanoparticles” that were optimized at T = 500 °C, time = 2 h, [Cu(NO3)2] = 0.1 mol dm−3, and pH 3. This was achieved by undertaking an orthogonal experiment design methodology and performing different instrumental analyses, such as X-ray diffractometry, inductively coupled plasma spectrometry, and transmission electron microscopy, along with treatment of the data by analysis of variance (ANOVA). The second goal of the study was elucidation of the mechanisms of effects of operational conditions (e.g., temperature) on the above-mentioned target parameters, through application of the appropriate mechanisms of formation of nanoparticles. Nanoparticles are suggested to form initially in the liquid phase as Cu(OH)2, which are later transformed to Cu2(OH)3NO3, through which CuO product is obtained. Decomposition of nitric acid also plays role in this mechanism. Fabricated nanoparticles are effective catalysts for the synthesis of benzoheterocycle compounds in the pharmaceutical industries. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1017089 Exemplaires
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Titre : Thermodynamic consistency test for experimental data of sulfur content of hydrogen sulfide Type de document : texte imprimé Auteurs : Ali Eslamimanesh, Auteur ; Amir H. Mohammadi, Auteur ; Dominique Richon, Auteur Année de publication : 2011 Article en page(s) : pp. 3555-3563 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydrogen sulfides Résumé : Accurate knowledge of the sulfur content of hydrogen sulfide vapor is an important factor for prediction of the sulfur precipitation conditions in production of many sour natural gases. However, limited data regarding the sulfur content of hydrogen sulfide are available in the open literature. This is partly because of the fact that the concentration of sulfur in the vapor phase is very low. The measurement difficulties may consequently result in generating inaccurate and sometimes unreliable experimental data. This work aims at performing a thermodynamic consistency test based on area approach to study the reliability of some selected experimental data from the literature on the sulfur content of hydrogen sulfide vapor. The Peng-Robinson equation of state along with conventional mixing rules is used for thermodynamic modeling. In this model, sulfur molecules are treated as single molecules S8. The results show that almost 45% of all of the investigated experimental data are thermodynamically consistent, 45% are inconsistent, and 10% are not fully consistent. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944523
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3555-3563[article] Thermodynamic consistency test for experimental data of sulfur content of hydrogen sulfide [texte imprimé] / Ali Eslamimanesh, Auteur ; Amir H. Mohammadi, Auteur ; Dominique Richon, Auteur . - 2011 . - pp. 3555-3563.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3555-3563
Mots-clés : Hydrogen sulfides Résumé : Accurate knowledge of the sulfur content of hydrogen sulfide vapor is an important factor for prediction of the sulfur precipitation conditions in production of many sour natural gases. However, limited data regarding the sulfur content of hydrogen sulfide are available in the open literature. This is partly because of the fact that the concentration of sulfur in the vapor phase is very low. The measurement difficulties may consequently result in generating inaccurate and sometimes unreliable experimental data. This work aims at performing a thermodynamic consistency test based on area approach to study the reliability of some selected experimental data from the literature on the sulfur content of hydrogen sulfide vapor. The Peng-Robinson equation of state along with conventional mixing rules is used for thermodynamic modeling. In this model, sulfur molecules are treated as single molecules S8. The results show that almost 45% of all of the investigated experimental data are thermodynamically consistent, 45% are inconsistent, and 10% are not fully consistent. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944523 Exemplaires
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Titre : Synthesis of spherical polyelectrolyte brushes by photoemulsion polymerization with different photoinitiators Type de document : texte imprimé Auteurs : Xiang Wang, Auteur ; Shuang Wu, Auteur ; Li, L., Auteur Année de publication : 2011 Article en page(s) : pp. 3564–3569 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : kinetics Photoemulsion Polymerization Résumé : Nanosized spherical polyelectrolyte brushes (SPBs) with tunable size and grafting density were synthesized successfully by photoemulsion polymerization using three photoinitiators. Due to their difference in structure, UV absorption, and mechanism of photoinitiation, the kinetics of photoemulsion polymerization using these respective photoinitiators are different. The grafting densities of poly(acrylic acid) (PAA) brushes varied from 0.012 to 0.081 nm−2 by using different photoinitiators, as determined by cutting off the PAA chains from the core particles. All of the spherical PAA brushes prepared by these three photoinitiators are pH and ionic strength sensitive as demonstrated by DLS measurements. Well-defined spherical morphology with narrow size distribution for all of the brushes prepared has been observed by FESEM. This work opens a new way to control the synthesis of SPBs with tunable structure for potential applications in catalysis, wastewater treatment, disease diagnosis, and protein immobilization. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101764s
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3564–3569[article] Synthesis of spherical polyelectrolyte brushes by photoemulsion polymerization with different photoinitiators [texte imprimé] / Xiang Wang, Auteur ; Shuang Wu, Auteur ; Li, L., Auteur . - 2011 . - pp. 3564–3569.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3564–3569
Mots-clés : kinetics Photoemulsion Polymerization Résumé : Nanosized spherical polyelectrolyte brushes (SPBs) with tunable size and grafting density were synthesized successfully by photoemulsion polymerization using three photoinitiators. Due to their difference in structure, UV absorption, and mechanism of photoinitiation, the kinetics of photoemulsion polymerization using these respective photoinitiators are different. The grafting densities of poly(acrylic acid) (PAA) brushes varied from 0.012 to 0.081 nm−2 by using different photoinitiators, as determined by cutting off the PAA chains from the core particles. All of the spherical PAA brushes prepared by these three photoinitiators are pH and ionic strength sensitive as demonstrated by DLS measurements. Well-defined spherical morphology with narrow size distribution for all of the brushes prepared has been observed by FESEM. This work opens a new way to control the synthesis of SPBs with tunable structure for potential applications in catalysis, wastewater treatment, disease diagnosis, and protein immobilization. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101764s Exemplaires
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Titre : Performance of an internal combustion engine operating on landfill gas and the effect of syngas addition Type de document : texte imprimé Auteurs : Mckenzie P. Kohn, Auteur ; Jechan Lee, Auteur ; Matthew L. Basinger, Auteur Année de publication : 2011 Article en page(s) : pp. 3570-3579 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Synthesis gas Waste dumping Combustion Résumé : The performance of a four-stroke Honda GC160E spark ignition (SI) internal combustion (IC) engine operating on landfill gas (LFG) was investigated, as well as the impact ofH2 and CO (syngas) addition on emissions and engine efficiency. Tests were performed for engine loads from 0.2 to 0.8 kW over a range of CO2 to CH4 ratios (0-0.50). In addition, variation across both the syngas content (up to 15%) and the ratio of H2 to CO in the syngas (H2/CO = 0.5, 1, and 2) were tested. Catalytic testing provided reactor data on the amount of syngas and H2/CO ratios that can be obtained by autothermally reforming LFG. The emissions obtained from the test engine fueled with the simulated LFG were found to be comparable to emissions from commercial LFG to energy (LFGTE) systems currently deployed. Syngas addition was found to not only significantly reduce CO, unburned hydrocarbon (UHC), and NOx emissions but also improve brake efficiency of the engine. CO emissions were reduced from 802 to 214 ppm for a 5% syngas addition and to 230 and 247 ppm for 10 and 15% syngas addition, respectively. UHC emissions were reduced from 113 ppm to approximately 12 ppm for all amounts of syngas addition. Syngas addition decreased NOx from 100 to 62 ppm for 5% syngas and 71 and 76 ppm for 10 and 15% syngas, respectively. Finally, the brake efficiency increased by approximately 10% with the addition of 5% syngas. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944525
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3570-3579[article] Performance of an internal combustion engine operating on landfill gas and the effect of syngas addition [texte imprimé] / Mckenzie P. Kohn, Auteur ; Jechan Lee, Auteur ; Matthew L. Basinger, Auteur . - 2011 . - pp. 3570-3579.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3570-3579
Mots-clés : Synthesis gas Waste dumping Combustion Résumé : The performance of a four-stroke Honda GC160E spark ignition (SI) internal combustion (IC) engine operating on landfill gas (LFG) was investigated, as well as the impact ofH2 and CO (syngas) addition on emissions and engine efficiency. Tests were performed for engine loads from 0.2 to 0.8 kW over a range of CO2 to CH4 ratios (0-0.50). In addition, variation across both the syngas content (up to 15%) and the ratio of H2 to CO in the syngas (H2/CO = 0.5, 1, and 2) were tested. Catalytic testing provided reactor data on the amount of syngas and H2/CO ratios that can be obtained by autothermally reforming LFG. The emissions obtained from the test engine fueled with the simulated LFG were found to be comparable to emissions from commercial LFG to energy (LFGTE) systems currently deployed. Syngas addition was found to not only significantly reduce CO, unburned hydrocarbon (UHC), and NOx emissions but also improve brake efficiency of the engine. CO emissions were reduced from 802 to 214 ppm for a 5% syngas addition and to 230 and 247 ppm for 10 and 15% syngas addition, respectively. UHC emissions were reduced from 113 ppm to approximately 12 ppm for all amounts of syngas addition. Syngas addition decreased NOx from 100 to 62 ppm for 5% syngas and 71 and 76 ppm for 10 and 15% syngas, respectively. Finally, the brake efficiency increased by approximately 10% with the addition of 5% syngas. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944525 Exemplaires
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Titre : Sparger type influence on the hydrodynamics of the draft tube airlift reactor with diluted alcohol - solutions Type de document : texte imprimé Auteurs : Ivana M. Šijacki, Auteur ; Milenko S. Tokic, Auteur ; Predrag S. Kojic, Auteur Année de publication : 2011 Article en page(s) : pp. 3580-3591 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Bioreactor Alcoholic solution Airlift reactor Draft tube Hydrodynamics Résumé : The objective of this work was to investigate the influence of normal aliphatic alcohols (from methanol to n-octanol) and the gas sparger type (single orifice, perforated plate, and sinter plate) on the hydrodynamics of a draft tube airlift reactor. The results showed that the presence of alcohols led to both an increase in the gas holdup and reduction of the downcomer liquid velocity, in comparison to the values obtained in water. The type of gas sparger also changed the hydrodynamic behavior-the gas holdup increased with dispersion effectiveness, from single orifice to sinter plate, while the effect on the downcomer liquid velocity was in conjunction with the liquid phase properties. Simple correlations were developed to predict the gas holdup and the downcomer liquid velocity. Beside the gas superficial velocity, the proposed correlations include the surface tension gradient, as a unique parameter which represents the liquid phase properties, and sparger related variables: the ratio of the sparger's total openings area and the draft tube cross-sectional area and also orifice (pore) size of the sparger. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944526
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3580-3591[article] Sparger type influence on the hydrodynamics of the draft tube airlift reactor with diluted alcohol - solutions [texte imprimé] / Ivana M. Šijacki, Auteur ; Milenko S. Tokic, Auteur ; Predrag S. Kojic, Auteur . - 2011 . - pp. 3580-3591.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3580-3591
Mots-clés : Bioreactor Alcoholic solution Airlift reactor Draft tube Hydrodynamics Résumé : The objective of this work was to investigate the influence of normal aliphatic alcohols (from methanol to n-octanol) and the gas sparger type (single orifice, perforated plate, and sinter plate) on the hydrodynamics of a draft tube airlift reactor. The results showed that the presence of alcohols led to both an increase in the gas holdup and reduction of the downcomer liquid velocity, in comparison to the values obtained in water. The type of gas sparger also changed the hydrodynamic behavior-the gas holdup increased with dispersion effectiveness, from single orifice to sinter plate, while the effect on the downcomer liquid velocity was in conjunction with the liquid phase properties. Simple correlations were developed to predict the gas holdup and the downcomer liquid velocity. Beside the gas superficial velocity, the proposed correlations include the surface tension gradient, as a unique parameter which represents the liquid phase properties, and sparger related variables: the ratio of the sparger's total openings area and the draft tube cross-sectional area and also orifice (pore) size of the sparger. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944526 Exemplaires
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Titre : Measurement and correlation of the solubility of ammonia in ethanol between 277.35 and 318.25 K Type de document : texte imprimé Auteurs : Zuo-Xiang Zeng, Auteur ; Jing Chen, Auteur ; Wei-Lan Xue, Auteur Année de publication : 2011 Article en page(s) : pp. 3592–3597 Langues : Anglais (eng) Mots-clés : Solubility ammonia Ethanol Résumé : The solubility of ammonia in ethanol was measured by a static−analytic method. The total pressure is up to about 0.4 MPa, and temperature ranges from (277.35 to 318.25) K. The relationship between the partial molar volume of ammonia infinitely diluted in ethanol and temperature is obtained by measuring the density of (ethanol + ammonia) solution. The experimental results are used to determine the (molality scale based) Henry’s constant of ammonia in ethanol, where the activity in the liquid phase is calculated by applying the molality scale based Gibbs excess energy model of Pitzer. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102089x
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3592–3597[article] Measurement and correlation of the solubility of ammonia in ethanol between 277.35 and 318.25 K [texte imprimé] / Zuo-Xiang Zeng, Auteur ; Jing Chen, Auteur ; Wei-Lan Xue, Auteur . - 2011 . - pp. 3592–3597.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3592–3597
Mots-clés : Solubility ammonia Ethanol Résumé : The solubility of ammonia in ethanol was measured by a static−analytic method. The total pressure is up to about 0.4 MPa, and temperature ranges from (277.35 to 318.25) K. The relationship between the partial molar volume of ammonia infinitely diluted in ethanol and temperature is obtained by measuring the density of (ethanol + ammonia) solution. The experimental results are used to determine the (molality scale based) Henry’s constant of ammonia in ethanol, where the activity in the liquid phase is calculated by applying the molality scale based Gibbs excess energy model of Pitzer. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102089x Exemplaires
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Titre : Hydrodynamics and adsorption mass transfer in a novel gas − liquid − solid circulating fluidized bed adsorber Type de document : texte imprimé Auteurs : Tan Lin, Auteur ; Liu Mingyan, Auteur ; Hu Zongding, Auteur Année de publication : 2011 Article en page(s) : pp. 3598–3612 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydrodynamics Mass transfer Résumé : A novel gas−liquid−solid circulating fluidized bed adsorber for the separation of natural products or traditional Chinese medicines from extracts was successfully developed in this work. The hydrodynamics, axial dispersion, and mixing characteristics of phases and the adsorption and desorption of Ginkgo flavonoids in macroporous resin particles with prepared extract were investigated. The results showed that with the increase of downer superficial gas velocity, the deviation degree of flow pattern from plug flow, and the liquid back-mixing in the downer were enhanced because the liquid Pe number of the downer became smaller while its axial dispersion coefficient got larger. Similar tends were found for the riser as the riser superficial gas velocity climbed. Compared with that of the downer, the flow in the riser was more close to plug flow. Investigations on the adsorption kinetics of macroporous resin particles showed that the adsorption separation of Ginkgo flavonoids from extract was controlled by the surface film mass transfer and intraparticle diffusion. Experimental results of adsorption separation of Ginkgo flavonoids in the three-phase circulating fluidized bed indicated that the air bubbles introduced in a liquid−solid circulating fluidized bed could enhance the adsorption and desorption processes, and smaller particles, lower superficial feed velocity, and adsorbate concentration were favorable for the three-phase circulating fluidized bed adsorption separation. The adsorption model of the downer and the desorption model of the riser were built, and they predicted the adsorption and desorption processes well. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102113u
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3598–3612[article] Hydrodynamics and adsorption mass transfer in a novel gas − liquid − solid circulating fluidized bed adsorber [texte imprimé] / Tan Lin, Auteur ; Liu Mingyan, Auteur ; Hu Zongding, Auteur . - 2011 . - pp. 3598–3612.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3598–3612
Mots-clés : Hydrodynamics Mass transfer Résumé : A novel gas−liquid−solid circulating fluidized bed adsorber for the separation of natural products or traditional Chinese medicines from extracts was successfully developed in this work. The hydrodynamics, axial dispersion, and mixing characteristics of phases and the adsorption and desorption of Ginkgo flavonoids in macroporous resin particles with prepared extract were investigated. The results showed that with the increase of downer superficial gas velocity, the deviation degree of flow pattern from plug flow, and the liquid back-mixing in the downer were enhanced because the liquid Pe number of the downer became smaller while its axial dispersion coefficient got larger. Similar tends were found for the riser as the riser superficial gas velocity climbed. Compared with that of the downer, the flow in the riser was more close to plug flow. Investigations on the adsorption kinetics of macroporous resin particles showed that the adsorption separation of Ginkgo flavonoids from extract was controlled by the surface film mass transfer and intraparticle diffusion. Experimental results of adsorption separation of Ginkgo flavonoids in the three-phase circulating fluidized bed indicated that the air bubbles introduced in a liquid−solid circulating fluidized bed could enhance the adsorption and desorption processes, and smaller particles, lower superficial feed velocity, and adsorbate concentration were favorable for the three-phase circulating fluidized bed adsorption separation. The adsorption model of the downer and the desorption model of the riser were built, and they predicted the adsorption and desorption processes well. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102113u Exemplaires
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Titre : Thermodynamics of multicomponent PAH mixtures and development of tarlike behavior Type de document : texte imprimé Auteurs : James W. Rice, Auteur ; Jinxia Fu, Auteur ; Eric M. Suuberg, Auteur Année de publication : 2011 Article en page(s) : pp. 3613–3620 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Thermodynamics Résumé : This study explores the solid/liquid phase behavior of mixtures of polycyclic aromatic hydrocarbons (PAHs), exploring the transition from nonideal solid mixtures to a relatively ideal liquid behavior characteristic of “tars”. PAH mixtures have been studied using differential scanning calorimetry, melting point analysis and Knudsen effusion. Mixtures of anthracene, pyrene, and fluoranthene show behavior that is consistent with other binary PAH mixtures; that is, the initially solid mixture exhibits a significant melting point depression, relative to the pure components, and in a certain range of composition, solid azeotrope behavior on vaporization. As the number of distinct PAH species is increased (by adding in benzo[a]pyrene, phenanthrene, fluorene, and chrysene), this behavior gradually gives way to liquid phase character at even room temperature, and the vaporization behavior approaches that crudely predictable from ideal mixture theory. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102325d
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3613–3620[article] Thermodynamics of multicomponent PAH mixtures and development of tarlike behavior [texte imprimé] / James W. Rice, Auteur ; Jinxia Fu, Auteur ; Eric M. Suuberg, Auteur . - 2011 . - pp. 3613–3620.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3613–3620
Mots-clés : Thermodynamics Résumé : This study explores the solid/liquid phase behavior of mixtures of polycyclic aromatic hydrocarbons (PAHs), exploring the transition from nonideal solid mixtures to a relatively ideal liquid behavior characteristic of “tars”. PAH mixtures have been studied using differential scanning calorimetry, melting point analysis and Knudsen effusion. Mixtures of anthracene, pyrene, and fluoranthene show behavior that is consistent with other binary PAH mixtures; that is, the initially solid mixture exhibits a significant melting point depression, relative to the pure components, and in a certain range of composition, solid azeotrope behavior on vaporization. As the number of distinct PAH species is increased (by adding in benzo[a]pyrene, phenanthrene, fluorene, and chrysene), this behavior gradually gives way to liquid phase character at even room temperature, and the vaporization behavior approaches that crudely predictable from ideal mixture theory. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102325d Exemplaires
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Titre : Thermodynamics of phase equilibria in aqueous strong electrolyte systems Type de document : texte imprimé Auteurs : Mi-Yi Li, Auteur ; Li-Sheng Wang, Auteur ; Jürgen Gmehling, Auteur Année de publication : 2011 Article en page(s) : pp. 3621-3631 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Strong electrolyte Phase equilibrium Résumé : The middle range (MR) parameters of the LIQUAC model were improved as a function of temperature to allow the calculation of the activities of all the species in the solution over a wide temperature and concentration range. New parameters were recorrelated by using the experimental data of osmotic coefficients, vapor-liquid equilibria (VLE), mean ion activity coefficients and salt solubilities from the Dortmund Data Bank (DDB). The coordinates of the eutectics, the peritectics, and the ice-water equilibria of the aqueous electrolyte systems were represented with the model. Standard Gibbs energies of formation, standard enthalpies of formation, and heat capacities of various solids were retrieved from the fitting of their solubility products with respect to temperature or estimated using the group contribution method. The schematic phase diagrams for the salts in aqueous systems are presented in this work. A good agreement of calculated results with the published measurements is observed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944530
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3621-3631[article] Thermodynamics of phase equilibria in aqueous strong electrolyte systems [texte imprimé] / Mi-Yi Li, Auteur ; Li-Sheng Wang, Auteur ; Jürgen Gmehling, Auteur . - 2011 . - pp. 3621-3631.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3621-3631
Mots-clés : Strong electrolyte Phase equilibrium Résumé : The middle range (MR) parameters of the LIQUAC model were improved as a function of temperature to allow the calculation of the activities of all the species in the solution over a wide temperature and concentration range. New parameters were recorrelated by using the experimental data of osmotic coefficients, vapor-liquid equilibria (VLE), mean ion activity coefficients and salt solubilities from the Dortmund Data Bank (DDB). The coordinates of the eutectics, the peritectics, and the ice-water equilibria of the aqueous electrolyte systems were represented with the model. Standard Gibbs energies of formation, standard enthalpies of formation, and heat capacities of various solids were retrieved from the fitting of their solubility products with respect to temperature or estimated using the group contribution method. The schematic phase diagrams for the salts in aqueous systems are presented in this work. A good agreement of calculated results with the published measurements is observed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944530 Exemplaires
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