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Vol. 47 N°20 - Octobre 2008 [texte imprimé] . - 2008 . - p. 7509-7964 : ill. ; 28 cm. Chemical engineering Langues : Anglais (eng)
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Ajouter le résultat dans votre panierTransversal hot zones formation in catalytic packed-bed reactors / Ganesh A. Viswanathan in Industrial & engineering chemistry research, Vol. 47 N°20 (Octobre 2008)
Titre : Transversal hot zones formation in catalytic packed-bed reactors Type de document : texte imprimé Auteurs : Ganesh A. Viswanathan, Éditeur scientifique ; Moshe Sheintuch, Éditeur scientifique ; Dan Luss, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7509-7523 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hot zones Catalytic reactors Packed-bed (PBRs) Résumé : Spatiotemporal patterns reported to form in the cross sections of packed-bed reactors (PBRs) may pose severe safety hazard when present next to the reactor wall. Understanding what causes their formation and dynamic features is essential for the rational development of design and control strategies that circumvent their generation. We review the current knowledge and understanding about the formation of these transversal temperature patterns. Simulations and model analysis revealed that the formation of the hot spots and their dynamics are sensitive to the assumed kinetic and reactor models. Under practical conditions, stable symmetry-breaking bifurcation to nonuniform states, from stable, stationary, transversally uniform states cannot be predicted by common PBR models with a rate expression that depends only on the surface temperature and concentration of the limiting reactant. However, analysis and simulations reveal that transient nonuniform transversal temperatures may emerge in an upstream moving traveling front under practical conditions. Microkinetic oscillatory reactions predict the formation of a plethora of intricate spatiotemporal temperature patterns and temperature front motions that are sensitive to the reactor operating conditions and properties such as diameter and initial conditions. The predicted temperature patterns may be rather intricate as a result of conjugation of several modes. The nonlinear coupling between the states at different axial positions, that is, the interaction among the local temperature and concentrations at different cross-sections of the bed, may explain the intricate conjugation of several modes and modulation of the observed spatiotemporal patterns. While some simulations predicted spatiotemporal pattern evolution in PBRs, there is a need to understand which reaction mechanisms may lead to their formation. Most previous simulations and analysis utilized two-dimensional reactor models. However, hot zones are three-dimensional structures, often very small, and difficult to detect in large reactors. A 3-D simulation, although tedious, is necessary to provide full information about the size, shape and dynamic features of small hot zones. Moreover, common PBR models may have to be modified to account for the impact of local states such as flow distribution and nonuniform packing. Verification of the various model predictions requires in situ measurements of 3-D hot zones. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8005726
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7509-7523[article] Transversal hot zones formation in catalytic packed-bed reactors [texte imprimé] / Ganesh A. Viswanathan, Éditeur scientifique ; Moshe Sheintuch, Éditeur scientifique ; Dan Luss, Éditeur scientifique . - 2008 . - P. 7509-7523.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7509-7523
Mots-clés : Hot zones Catalytic reactors Packed-bed (PBRs) Résumé : Spatiotemporal patterns reported to form in the cross sections of packed-bed reactors (PBRs) may pose severe safety hazard when present next to the reactor wall. Understanding what causes their formation and dynamic features is essential for the rational development of design and control strategies that circumvent their generation. We review the current knowledge and understanding about the formation of these transversal temperature patterns. Simulations and model analysis revealed that the formation of the hot spots and their dynamics are sensitive to the assumed kinetic and reactor models. Under practical conditions, stable symmetry-breaking bifurcation to nonuniform states, from stable, stationary, transversally uniform states cannot be predicted by common PBR models with a rate expression that depends only on the surface temperature and concentration of the limiting reactant. However, analysis and simulations reveal that transient nonuniform transversal temperatures may emerge in an upstream moving traveling front under practical conditions. Microkinetic oscillatory reactions predict the formation of a plethora of intricate spatiotemporal temperature patterns and temperature front motions that are sensitive to the reactor operating conditions and properties such as diameter and initial conditions. The predicted temperature patterns may be rather intricate as a result of conjugation of several modes. The nonlinear coupling between the states at different axial positions, that is, the interaction among the local temperature and concentrations at different cross-sections of the bed, may explain the intricate conjugation of several modes and modulation of the observed spatiotemporal patterns. While some simulations predicted spatiotemporal pattern evolution in PBRs, there is a need to understand which reaction mechanisms may lead to their formation. Most previous simulations and analysis utilized two-dimensional reactor models. However, hot zones are three-dimensional structures, often very small, and difficult to detect in large reactors. A 3-D simulation, although tedious, is necessary to provide full information about the size, shape and dynamic features of small hot zones. Moreover, common PBR models may have to be modified to account for the impact of local states such as flow distribution and nonuniform packing. Verification of the various model predictions requires in situ measurements of 3-D hot zones. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8005726 Exemplaires
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Titre : Current research and development status and prospect of hot-melt adhesives : a review Type de document : texte imprimé Auteurs : Li, Wen, Éditeur scientifique ; Laziz Bouzidi, Éditeur scientifique ; Suresh S. Narine, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7524-7532 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hot-melt adhesives (HMAs) Résumé : Fundamental characteristics, general physical and mechanical behavior, and the recent developments in the knowledge of hot-melt adhesives (HMAs) are introduced. The current research and development status for HMAs is reviewed, with an emphasis on the development of new types/generations of HMAs. In particular, some crucial issues and challenges on the technological improvements and the materials development are discussed. On the basis of the current predicted shortage of energy resources and environmental concerns, prospective research on the development of green HMAs is suggested. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800189b
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7524-7532[article] Current research and development status and prospect of hot-melt adhesives : a review [texte imprimé] / Li, Wen, Éditeur scientifique ; Laziz Bouzidi, Éditeur scientifique ; Suresh S. Narine, Éditeur scientifique . - 2008 . - P. 7524-7532.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7524-7532
Mots-clés : Hot-melt adhesives (HMAs) Résumé : Fundamental characteristics, general physical and mechanical behavior, and the recent developments in the knowledge of hot-melt adhesives (HMAs) are introduced. The current research and development status for HMAs is reviewed, with an emphasis on the development of new types/generations of HMAs. In particular, some crucial issues and challenges on the technological improvements and the materials development are discussed. On the basis of the current predicted shortage of energy resources and environmental concerns, prospective research on the development of green HMAs is suggested. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800189b Exemplaires
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Titre : Determination of the solubility products in water at 20 °C of 32 metallic carboxylates Type de document : texte imprimé Auteurs : Stéphanie Mauchauffee, Éditeur scientifique ; Eric Meux, Éditeur scientifique ; Michel Schneider, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7533-7537 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Metallic carboxylates Carbons Résumé : The solubility products of 32 metallic carboxylates resulting from the precipitation of seven cations (Cd, Co, Cu, Mn, Ni, Pb, and Zn) with six linear saturated carboxylates (heptanoate, octanoate, nonanoate, decanoate, dodecanoate, and octadecanoate) are reported. Solubility measurements were performed using the analytical method with freshly precipitated metallic carboxylates. From the measured metal concentration and equilibrium pH value, solubility products, Ksp, were determined. The results indicate a linear relationship between the negative logarithm of the solubility product and the carbon number in the aliphatic chain that is valid from 7 to 12 carbons. The determination of the pKsp value of copper octadecanoate shows the limit of the linear model. Indeed, the experimental value obtained demonstrates that pKsp tends to a limiting value and becomes independent of the chain length. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071595a
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7533-7537[article] Determination of the solubility products in water at 20 °C of 32 metallic carboxylates [texte imprimé] / Stéphanie Mauchauffee, Éditeur scientifique ; Eric Meux, Éditeur scientifique ; Michel Schneider, Éditeur scientifique . - 2008 . - P. 7533-7537.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7533-7537
Mots-clés : Metallic carboxylates Carbons Résumé : The solubility products of 32 metallic carboxylates resulting from the precipitation of seven cations (Cd, Co, Cu, Mn, Ni, Pb, and Zn) with six linear saturated carboxylates (heptanoate, octanoate, nonanoate, decanoate, dodecanoate, and octadecanoate) are reported. Solubility measurements were performed using the analytical method with freshly precipitated metallic carboxylates. From the measured metal concentration and equilibrium pH value, solubility products, Ksp, were determined. The results indicate a linear relationship between the negative logarithm of the solubility product and the carbon number in the aliphatic chain that is valid from 7 to 12 carbons. The determination of the pKsp value of copper octadecanoate shows the limit of the linear model. Indeed, the experimental value obtained demonstrates that pKsp tends to a limiting value and becomes independent of the chain length. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071595a Exemplaires
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Titre : Effect of oxidizers on microwave-assisted oxidative degradation of poly(alkyl acrylates) Type de document : texte imprimé Auteurs : A. Marimuthu, Éditeur scientifique ; Giridhar Madras, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7538-7544 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Effect of oxidizers Microwave-assisted oxidative Poly(methyl acrylate) (PMA) Poly(ethyl (PEA) Résumé : The effect of oxidizers on the microwave-assisted oxidative degradation kinetics of poly(alkyl acrylates), namely, poly(methyl acrylate) (PMA), poly(ethyl acrylate) (PEA), and poly(butyl acrylate) (PBA), was studied. The molecular weight distributions were measured by gel permeation chromatography, and continuous distribution kinetic models were used to determine the degradation rate coefficients. The effect of alkyl group substituents on the microwave-assisted oxidative degradation of poly(alkyl acrylates) was also investigated. The degradation rate of poly(alkyl acrylates) decreased with an increase in the number of carbon atoms of the alkyl substituents and thus followed the order PMA > PEA > PBA, while the activation energy increased with the length of alkyl group substituents. The rate coefficients of hydrogen abstraction and oxidative random chain scission were found to be independent of the oxidizer and dependent only on the nature of the polymer. The differences in the overall degradation rate of poly(ethyl acrylate) in the presence of different oxidizing agents were only dependent on the rate of oxidizer dissociation. This is the first study that shows that the degradation rate of the polymer in the presence of any oxidizer can be predicted by knowing only the thermal dissociation rate constant values of the oxidizer, which can be easily obtained from existing literature. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie7017349
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7538-7544[article] Effect of oxidizers on microwave-assisted oxidative degradation of poly(alkyl acrylates) [texte imprimé] / A. Marimuthu, Éditeur scientifique ; Giridhar Madras, Éditeur scientifique . - 2008 . - P. 7538-7544.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7538-7544
Mots-clés : Effect of oxidizers Microwave-assisted oxidative Poly(methyl acrylate) (PMA) Poly(ethyl (PEA) Résumé : The effect of oxidizers on the microwave-assisted oxidative degradation kinetics of poly(alkyl acrylates), namely, poly(methyl acrylate) (PMA), poly(ethyl acrylate) (PEA), and poly(butyl acrylate) (PBA), was studied. The molecular weight distributions were measured by gel permeation chromatography, and continuous distribution kinetic models were used to determine the degradation rate coefficients. The effect of alkyl group substituents on the microwave-assisted oxidative degradation of poly(alkyl acrylates) was also investigated. The degradation rate of poly(alkyl acrylates) decreased with an increase in the number of carbon atoms of the alkyl substituents and thus followed the order PMA > PEA > PBA, while the activation energy increased with the length of alkyl group substituents. The rate coefficients of hydrogen abstraction and oxidative random chain scission were found to be independent of the oxidizer and dependent only on the nature of the polymer. The differences in the overall degradation rate of poly(ethyl acrylate) in the presence of different oxidizing agents were only dependent on the rate of oxidizer dissociation. This is the first study that shows that the degradation rate of the polymer in the presence of any oxidizer can be predicted by knowing only the thermal dissociation rate constant values of the oxidizer, which can be easily obtained from existing literature. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie7017349 Exemplaires
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Titre : Enhanced photocatalytic activity by silver metal ion exchanged naY zeolite photocatalysts for the degradation of organic contaminants and dyes in aqueous medium Type de document : texte imprimé Auteurs : Rajesh J. Tayade, Éditeur scientifique ; Praveen K. Surolia, Éditeur scientifique ; Manoj Lazar, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7545-7551 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Photocatalytic Zeolite-based photocatalyst X-ray diffraction (XRD) Scanning electron microscopy (SEM) TiO2 Résumé : Zeolite-based photocatalyst have been prepared using TiO2-coated NaY zeolite by post-synthesis modification with silver metal ion exchange. The characterization of the catalysts was carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM), Inductively coupled plasma-optical emission spectrophotometry (ICP), Diffuse reflectance spectroscopy (DRS), Fourier transform infrared spectroscopy (FTIR), and N2 adsorption techniques. The presence of metal ions and TiO2 on zeolite surface was observed by UV-visible diffuse reflectance spectroscopy. It was found that the structure of the support materials is retained after the silver metal ion exchange. The photocatalytic activity of the catalysts was studied by degradation of aqueous nitrobenzene, acetophenone, methylene blue, and malachite green in the presence of UV light. The highest photocatalytic activity was obtained for silver metal ion exchanged photocatalysts coated with TiO2 (2%, w/w) as compared to other silver exchanged NaY zeolite catalysts. This study demonstrated that the Ag metal ion exchanged TiO2-coated NaY is a better catalyst as compared to the TiO2-coated NaY photocatalysts. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800441c
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7545-7551[article] Enhanced photocatalytic activity by silver metal ion exchanged naY zeolite photocatalysts for the degradation of organic contaminants and dyes in aqueous medium [texte imprimé] / Rajesh J. Tayade, Éditeur scientifique ; Praveen K. Surolia, Éditeur scientifique ; Manoj Lazar, Éditeur scientifique . - 2008 . - P. 7545-7551.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7545-7551
Mots-clés : Photocatalytic Zeolite-based photocatalyst X-ray diffraction (XRD) Scanning electron microscopy (SEM) TiO2 Résumé : Zeolite-based photocatalyst have been prepared using TiO2-coated NaY zeolite by post-synthesis modification with silver metal ion exchange. The characterization of the catalysts was carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM), Inductively coupled plasma-optical emission spectrophotometry (ICP), Diffuse reflectance spectroscopy (DRS), Fourier transform infrared spectroscopy (FTIR), and N2 adsorption techniques. The presence of metal ions and TiO2 on zeolite surface was observed by UV-visible diffuse reflectance spectroscopy. It was found that the structure of the support materials is retained after the silver metal ion exchange. The photocatalytic activity of the catalysts was studied by degradation of aqueous nitrobenzene, acetophenone, methylene blue, and malachite green in the presence of UV light. The highest photocatalytic activity was obtained for silver metal ion exchanged photocatalysts coated with TiO2 (2%, w/w) as compared to other silver exchanged NaY zeolite catalysts. This study demonstrated that the Ag metal ion exchanged TiO2-coated NaY is a better catalyst as compared to the TiO2-coated NaY photocatalysts. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800441c Exemplaires
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Titre : Production of tetramethyl ammonium hydroxide using bipolar membrane electrodialysis Type de document : texte imprimé Auteurs : Haozhe Feng, Éditeur scientifique ; Chuanhui Huang, Éditeur scientifique ; Tongwen Xu, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7552-7557 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Tetramethyl ammonium hydroxide (TMAH) Bipolar membrane electrodialysis (BMED) Résumé : To produce tetramethyl ammonium hydroxide (TMAH) at lower energy consumption and with less environmental pollution, a bipolar membrane electrodialysis (BMED) of A-BP configuration (A, anion exchange membrane; BP, bipolar membrane) was adopted to electro-alkalize tetramethyl ammonium chloride. The results for one-unit BMED stack indicate that current efficiency increases and energy consumption decreases as feed concentration increases or current density decreases. The highest current efficiency can reach 99.9%, and the lowest energy consumption is 1.43 kWh kg−1. On the basis of a 3-unit BMED, the process cost is estimated to be 0.33 $ kg−1 of TMAH. This method is not only environmentally friendly but also cost-effective. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800558m
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7552-7557[article] Production of tetramethyl ammonium hydroxide using bipolar membrane electrodialysis [texte imprimé] / Haozhe Feng, Éditeur scientifique ; Chuanhui Huang, Éditeur scientifique ; Tongwen Xu, Éditeur scientifique . - 2008 . - P. 7552-7557.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7552-7557
Mots-clés : Tetramethyl ammonium hydroxide (TMAH) Bipolar membrane electrodialysis (BMED) Résumé : To produce tetramethyl ammonium hydroxide (TMAH) at lower energy consumption and with less environmental pollution, a bipolar membrane electrodialysis (BMED) of A-BP configuration (A, anion exchange membrane; BP, bipolar membrane) was adopted to electro-alkalize tetramethyl ammonium chloride. The results for one-unit BMED stack indicate that current efficiency increases and energy consumption decreases as feed concentration increases or current density decreases. The highest current efficiency can reach 99.9%, and the lowest energy consumption is 1.43 kWh kg−1. On the basis of a 3-unit BMED, the process cost is estimated to be 0.33 $ kg−1 of TMAH. This method is not only environmentally friendly but also cost-effective. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800558m Exemplaires
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Titre : Effect of alkyl derivatization on several properties of N-halamine antimicrobial siloxane coatings Type de document : texte imprimé Auteurs : Hasan B. Kocer, Éditeur scientifique ; Akin Akdag, Éditeur scientifique ; Xuehong Ren, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7558-7563 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Alkyl derivatization N-Halamine Antimicrobial Résumé : Variation of alkyl substitution at position 5 on the hydantoin ring of a series of N-halamine siloxane derivatives has been employed to better understand the biocidal activities of these compounds for use in preparing antimicrobial coatings. The alkyl derivatization of the hydantoin ring at its 5 position, while an essentially constant chlorine loading is maintained at the 1 position, has shown that there is little dependence of the antimicrobial efficacy against Escherichia coli O157:H7 on the alkyl chain length, in contrast to reported observations for biocidal quaternary ammonium salt derivatives. The stabilities of the derivatives toward hydrolyses and ultraviolet light exposure have also been found to not be dependent upon the nature of the alkyl substituent group. These observations led to the conclusion that the 5,5-dimethyl derivative would be recommended for use, since it is the least expensive alternative. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800899u
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7558-7563[article] Effect of alkyl derivatization on several properties of N-halamine antimicrobial siloxane coatings [texte imprimé] / Hasan B. Kocer, Éditeur scientifique ; Akin Akdag, Éditeur scientifique ; Xuehong Ren, Éditeur scientifique . - 2008 . - P. 7558-7563.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7558-7563
Mots-clés : Alkyl derivatization N-Halamine Antimicrobial Résumé : Variation of alkyl substitution at position 5 on the hydantoin ring of a series of N-halamine siloxane derivatives has been employed to better understand the biocidal activities of these compounds for use in preparing antimicrobial coatings. The alkyl derivatization of the hydantoin ring at its 5 position, while an essentially constant chlorine loading is maintained at the 1 position, has shown that there is little dependence of the antimicrobial efficacy against Escherichia coli O157:H7 on the alkyl chain length, in contrast to reported observations for biocidal quaternary ammonium salt derivatives. The stabilities of the derivatives toward hydrolyses and ultraviolet light exposure have also been found to not be dependent upon the nature of the alkyl substituent group. These observations led to the conclusion that the 5,5-dimethyl derivative would be recommended for use, since it is the least expensive alternative. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800899u Exemplaires
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Titre : Heterogeneous photocatalytic oxidation of o-chloroaniline immobilizing on recyclable TiO2 Type de document : texte imprimé Auteurs : W. K. Choy, Éditeur scientifique ; W. Chu, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7564-7569 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Photocatalytic Oxidation TiO2 Résumé : A mixture of sol−gel and commercial TiO2 powder was immobilized on a film to faciliate photodegradation. The photodecay of o-ClA in the mixture of TiO2 sol−gel and powder was about 20% faster then that solely made by the sol−gel solution. The performance of TiO2 film depended on the annealing temperature applied. The transformation of photoactive anatase to rutile phase was observed above 450 °C, which resulted in a slower photodecay of o-ClA. The use of quartz as substrate has proven to be superior to glass in the photoreaction, owing to the excellent optical property of quartz. The o-ClA decay could be further improved by weight increment on the film. A linear relationship between decay rate and weight of coating was acquired. Furthermore, TiO2 coating was found to be dependent on the light intensity. The direct photolysis was determined to be insignificant in the process, while the photocatalytic ability was directly proportional to the amount of TiO2 film coated on the slide. For practical application, the recycling performance of the film was examined. The reuse of the TiO2 film showed a promising performance with very low variation (±7%) of decay rate after nine consecutive usages. A mathematical model was also proposed to predict the o-ClA removal performance based on the film mass and light intensity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800325v
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7564-7569[article] Heterogeneous photocatalytic oxidation of o-chloroaniline immobilizing on recyclable TiO2 [texte imprimé] / W. K. Choy, Éditeur scientifique ; W. Chu, Éditeur scientifique . - 2008 . - P. 7564-7569.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7564-7569
Mots-clés : Photocatalytic Oxidation TiO2 Résumé : A mixture of sol−gel and commercial TiO2 powder was immobilized on a film to faciliate photodegradation. The photodecay of o-ClA in the mixture of TiO2 sol−gel and powder was about 20% faster then that solely made by the sol−gel solution. The performance of TiO2 film depended on the annealing temperature applied. The transformation of photoactive anatase to rutile phase was observed above 450 °C, which resulted in a slower photodecay of o-ClA. The use of quartz as substrate has proven to be superior to glass in the photoreaction, owing to the excellent optical property of quartz. The o-ClA decay could be further improved by weight increment on the film. A linear relationship between decay rate and weight of coating was acquired. Furthermore, TiO2 coating was found to be dependent on the light intensity. The direct photolysis was determined to be insignificant in the process, while the photocatalytic ability was directly proportional to the amount of TiO2 film coated on the slide. For practical application, the recycling performance of the film was examined. The reuse of the TiO2 film showed a promising performance with very low variation (±7%) of decay rate after nine consecutive usages. A mathematical model was also proposed to predict the o-ClA removal performance based on the film mass and light intensity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800325v Exemplaires
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Titre : Lumped kinetics of self-heating runaway reactions : a statistical treatment Type de document : texte imprimé Auteurs : Enio Kumpinsky, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7570-7579 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Lumped kinetics Self-heating Chemical industry Statistical Treatment Résumé : The evaluation of laboratory-scale runaway reactions is of fundamental importance to safety studies that seek mitigation of hazards in the chemical industry. Such studies depend on reaction kinetics, which require good experimentation practices and effective interpretation of the results. Statistics offer many tools for the analysis of experimental data. Parameters can be estimated and re-evaluated to reduce collinearity between the factors. In addition, experimental variability and deficient model performance at temperatures in the neighborhood of venting conditions can be properly managed to provide conservative reaction rates without exaggerating the hazard. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714201
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7570-7579[article] Lumped kinetics of self-heating runaway reactions : a statistical treatment [texte imprimé] / Enio Kumpinsky, Éditeur scientifique . - 2008 . - P. 7570-7579.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7570-7579
Mots-clés : Lumped kinetics Self-heating Chemical industry Statistical Treatment Résumé : The evaluation of laboratory-scale runaway reactions is of fundamental importance to safety studies that seek mitigation of hazards in the chemical industry. Such studies depend on reaction kinetics, which require good experimentation practices and effective interpretation of the results. Statistics offer many tools for the analysis of experimental data. Parameters can be estimated and re-evaluated to reduce collinearity between the factors. In addition, experimental variability and deficient model performance at temperatures in the neighborhood of venting conditions can be properly managed to provide conservative reaction rates without exaggerating the hazard. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714201 Exemplaires
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Titre : Photocatalytic inactivation of airborne bacteria in a continuous-flow reactor Type de document : texte imprimé Auteurs : Amrita Pal, Éditeur scientifique ; Simo O. Pehkonen, Éditeur scientifique ; Liya E. Yu, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7580-7585 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Photocatalytic inactivation Airborne bacteria TiO2 kinetic data Résumé : In this study, a continuous annular reactor was used to characterize the TiO2-mediated inactivation of an aerosolized Gram-negative bacterium, Escherichia coli K-12 (ATCC 10798), by varying UV-A intensity (0.5−3.4 mW/cm2), relative humidity (RH) (from 51 ± 0.61 to 85 ± 4.7%), and photocatalyst loading (960 and 1516 mg/m2) at an air flow rate of 1 L/min. Inactivation rate of E. coli K-12 increased with an increase in TiO2 loading, UV-intensity, and RH. A UV-A dose of 0.03−0.204 J/cm2 at an average UV-A intensity of 0.5−3.4 mW/cm2, at a residence time of 1.1 min, is sufficient to fully and continuously inactivate E. coli K-12 passing through the reactor. The photocatalytic inactivation rates obtained in the continuous flow reactor compared well with our earlier batch inactivation rates conducted at a UV-A intensity of 0.015 mW/cm2 and a TiO2 loading of 1516 mg/m2. This demonstrates the possibility of scaling up of the photocatalytic inactivation process for bioaerosol based on batch kinetic data. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701739g
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7580-7585[article] Photocatalytic inactivation of airborne bacteria in a continuous-flow reactor [texte imprimé] / Amrita Pal, Éditeur scientifique ; Simo O. Pehkonen, Éditeur scientifique ; Liya E. Yu, Éditeur scientifique . - 2008 . - P. 7580-7585.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7580-7585
Mots-clés : Photocatalytic inactivation Airborne bacteria TiO2 kinetic data Résumé : In this study, a continuous annular reactor was used to characterize the TiO2-mediated inactivation of an aerosolized Gram-negative bacterium, Escherichia coli K-12 (ATCC 10798), by varying UV-A intensity (0.5−3.4 mW/cm2), relative humidity (RH) (from 51 ± 0.61 to 85 ± 4.7%), and photocatalyst loading (960 and 1516 mg/m2) at an air flow rate of 1 L/min. Inactivation rate of E. coli K-12 increased with an increase in TiO2 loading, UV-intensity, and RH. A UV-A dose of 0.03−0.204 J/cm2 at an average UV-A intensity of 0.5−3.4 mW/cm2, at a residence time of 1.1 min, is sufficient to fully and continuously inactivate E. coli K-12 passing through the reactor. The photocatalytic inactivation rates obtained in the continuous flow reactor compared well with our earlier batch inactivation rates conducted at a UV-A intensity of 0.015 mW/cm2 and a TiO2 loading of 1516 mg/m2. This demonstrates the possibility of scaling up of the photocatalytic inactivation process for bioaerosol based on batch kinetic data. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701739g Exemplaires
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Titre : Catalytic hydrogenation of dimethyl itaconate in a water-cyclohexane-triton X-100 microemulsion in comparison to a biphasic system Type de document : texte imprimé Auteurs : Juan S. Milano-Brusco, Éditeur scientifique ; Michael Schwarze, Éditeur scientifique ; M'hamed Djennad, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7586-7592 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Catalytic hydrogenation Dimethyl itaconate (DMI) Résumé : The kinetics of the catalytic hydrogenation of dimethyl itaconate (DMI) was studied in a biphasic cyclohexane−water system and in a [Triton X-100/1-pentanol]/cyclohexane/water microemulsion, in both cases using the water-soluble catalyst complex Rh−TPPTS. The reaction was carried out at a pressure of 1.1 bar and in the temperature range 298−308 K. A typical profile of a zero-order reaction was observed in the case of the biphasic system. Against that the reaction order for DMI changed to 1 in a microemulsion. A rate law based on an Osborn−Wilkinson-like kinetics was used to describe the experimental results which were governed by the irreversible attack of free DMI at the rhodium complex. The activation energy of the rate-determining step is 53 kJ mol−1 and is similar in both systems. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800190g
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7586-7592[article] Catalytic hydrogenation of dimethyl itaconate in a water-cyclohexane-triton X-100 microemulsion in comparison to a biphasic system [texte imprimé] / Juan S. Milano-Brusco, Éditeur scientifique ; Michael Schwarze, Éditeur scientifique ; M'hamed Djennad, Éditeur scientifique . - 2008 . - P. 7586-7592.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7586-7592
Mots-clés : Catalytic hydrogenation Dimethyl itaconate (DMI) Résumé : The kinetics of the catalytic hydrogenation of dimethyl itaconate (DMI) was studied in a biphasic cyclohexane−water system and in a [Triton X-100/1-pentanol]/cyclohexane/water microemulsion, in both cases using the water-soluble catalyst complex Rh−TPPTS. The reaction was carried out at a pressure of 1.1 bar and in the temperature range 298−308 K. A typical profile of a zero-order reaction was observed in the case of the biphasic system. Against that the reaction order for DMI changed to 1 in a microemulsion. A rate law based on an Osborn−Wilkinson-like kinetics was used to describe the experimental results which were governed by the irreversible attack of free DMI at the rhodium complex. The activation energy of the rate-determining step is 53 kJ mol−1 and is similar in both systems. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800190g Exemplaires
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Titre : Effect of operating pressure on the extent of hysteresis in a trickle bed reactor Type de document : texte imprimé Auteurs : Zeljko Kuzeljevic, Éditeur scientifique ; Werner van der Merwe, Éditeur scientifique ; Muthanna H. Al-Dahhan, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7593-7599 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Operating pressure Hydrodynamic parameters Résumé : The dependence of hydrodynamic parameters, such as pressure drop, on the flow history of the bed is called hysteresis. This phenomenon is most commonly associated with changes of flow distribution and flow patterns with the flow history. Many studies have shown that increased operating pressure will affect flow distribution and wetting efficiency; however, there seems to be no study of the effect of the elevated operating pressure on the extent of hysteresis. In this study, an experimental investigation of the hysteresis in a high-pressure trickle bed has been performed. A hysteresis factor has been introduced to quantify the extent of hysteresis and was found to be a strong function of gas and liquid operating flow rates as well as the operating pressure. In the region of lower liquid velocities, hysteresis is present regardless of the operating pressure or gas velocity. In the region of higher liquid velocities, increases in both pressure and gas velocity will lower the extent of hysteresis. For the range of conditions considered in this study, the extent of hysteresis was uniquely determined by the pressure drop in the Levec mode, regardless of the operating pressure or velocities. The results are interpreted in terms of the phenomenological analysis of Al-Dahhan and Dudukovic (Al-Dahhan, M. H.; Dudukovic, M. P. Chem. Eng. Sci. 1994, 49, 5681−98), which relates operating pressure and gas velocity to the flow distribution and wetting efficiency in a trickle bed reactor. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800255p
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7593-7599[article] Effect of operating pressure on the extent of hysteresis in a trickle bed reactor [texte imprimé] / Zeljko Kuzeljevic, Éditeur scientifique ; Werner van der Merwe, Éditeur scientifique ; Muthanna H. Al-Dahhan, Éditeur scientifique . - 2008 . - P. 7593-7599.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7593-7599
Mots-clés : Operating pressure Hydrodynamic parameters Résumé : The dependence of hydrodynamic parameters, such as pressure drop, on the flow history of the bed is called hysteresis. This phenomenon is most commonly associated with changes of flow distribution and flow patterns with the flow history. Many studies have shown that increased operating pressure will affect flow distribution and wetting efficiency; however, there seems to be no study of the effect of the elevated operating pressure on the extent of hysteresis. In this study, an experimental investigation of the hysteresis in a high-pressure trickle bed has been performed. A hysteresis factor has been introduced to quantify the extent of hysteresis and was found to be a strong function of gas and liquid operating flow rates as well as the operating pressure. In the region of lower liquid velocities, hysteresis is present regardless of the operating pressure or gas velocity. In the region of higher liquid velocities, increases in both pressure and gas velocity will lower the extent of hysteresis. For the range of conditions considered in this study, the extent of hysteresis was uniquely determined by the pressure drop in the Levec mode, regardless of the operating pressure or velocities. The results are interpreted in terms of the phenomenological analysis of Al-Dahhan and Dudukovic (Al-Dahhan, M. H.; Dudukovic, M. P. Chem. Eng. Sci. 1994, 49, 5681−98), which relates operating pressure and gas velocity to the flow distribution and wetting efficiency in a trickle bed reactor. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800255p Exemplaires
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Titre : HZSM-5 and HY zeolite catalyst performance in the pyrolysis of tires in a conical spouted bed reactor Type de document : texte imprimé Auteurs : Miriam Arabiourrutia, Éditeur scientifique ; Martin Olazar, Éditeur scientifique ; Roberto Aguado, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7600-7609 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Zeolite catalyst HZSM-5 zeolite HY Résumé : A study has been carried out on the in situ use of two catalysts (prepared based on HZSM-5 and HY zeolites) in the pyrolysis of tires in a conical spouted bed reactor at 425 and 500 °C. Both catalysts significantly affect the yields and composition obtained in thermal pyrolysis for the fractions corresponding to C1−C4 gases, nonaromatic C5−C10, aromatic C10−, and tar. The shape selectivity characteristic of each zeolite has a considerable influence on catalyst performance. The HZSM-5 zeolite catalyst produces an increase in the yield of gases, with an increase in the yield of propene and the same yield of butadiene as in thermal pyrolysis, in which it is already high. Concerning the liquid fraction, the catalysts give way to a decrease in the yield of d-limonene (the conical spouted bed reactor performs very well in thermal pyrolysis for this purpose), whereas the yield of BTX aromatics increases, with an increase in the yield of xylenes. A positive fact to be noted is the decrease in the formation of tar (C10+) compared to thermal pyrolysis. As the reaction occurs, a carbonaceous material is deposited on the catalyst, in which the following are identified: (i) carbon black externally coating the particles and deposited on the catalyst macropores and mesopores and (ii) coke deposited on zeolite micropores, due to hydrocarbon condensation activated by catalyst active sites. This condensation preferably takes place in the HY zeolite due to both the larger size of intersections between micropore channels and to greater hydrogen-transfer capacity. Nevertheless, under the reaction conditions tested (up to 10.87 g of tire treated/g of catalyst), product yields remain almost constant, which is evidence that the catalyst does not undergo deactivation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800376d
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7600-7609[article] HZSM-5 and HY zeolite catalyst performance in the pyrolysis of tires in a conical spouted bed reactor [texte imprimé] / Miriam Arabiourrutia, Éditeur scientifique ; Martin Olazar, Éditeur scientifique ; Roberto Aguado, Éditeur scientifique . - 2008 . - P. 7600-7609.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7600-7609
Mots-clés : Zeolite catalyst HZSM-5 zeolite HY Résumé : A study has been carried out on the in situ use of two catalysts (prepared based on HZSM-5 and HY zeolites) in the pyrolysis of tires in a conical spouted bed reactor at 425 and 500 °C. Both catalysts significantly affect the yields and composition obtained in thermal pyrolysis for the fractions corresponding to C1−C4 gases, nonaromatic C5−C10, aromatic C10−, and tar. The shape selectivity characteristic of each zeolite has a considerable influence on catalyst performance. The HZSM-5 zeolite catalyst produces an increase in the yield of gases, with an increase in the yield of propene and the same yield of butadiene as in thermal pyrolysis, in which it is already high. Concerning the liquid fraction, the catalysts give way to a decrease in the yield of d-limonene (the conical spouted bed reactor performs very well in thermal pyrolysis for this purpose), whereas the yield of BTX aromatics increases, with an increase in the yield of xylenes. A positive fact to be noted is the decrease in the formation of tar (C10+) compared to thermal pyrolysis. As the reaction occurs, a carbonaceous material is deposited on the catalyst, in which the following are identified: (i) carbon black externally coating the particles and deposited on the catalyst macropores and mesopores and (ii) coke deposited on zeolite micropores, due to hydrocarbon condensation activated by catalyst active sites. This condensation preferably takes place in the HY zeolite due to both the larger size of intersections between micropore channels and to greater hydrogen-transfer capacity. Nevertheless, under the reaction conditions tested (up to 10.87 g of tire treated/g of catalyst), product yields remain almost constant, which is evidence that the catalyst does not undergo deactivation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800376d Exemplaires
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Titre : CO2 sequestration potential of steel slags at ambient pressure and temperature Type de document : texte imprimé Auteurs : Danielle Bonenfant, Éditeur scientifique ; Lynda Kharoune, Éditeur scientifique ; Sébastien Sauve, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7610-7616 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Carbon dioxide Electric arc furnace (EAF) Ladle (LF) CO2 Résumé : A study of carbon dioxide sequestration has been performed in aqueous electric arc furnace (EAF) and ladle furnace (LF) slag suspensions, in leached hydrated-matrixes, and in leachates to estimate their intrinsic sequestration potential at ambient conditions (temperature of 20 ± 1 °C and atmospheric pressure). The CO2 sequestration was tested in aqueous suspensions of steel slags at a liquid-to-solid ratio of 10 kg/kg as well as in leached hydrated-matrixes and leachates isolated from these fresh slag suspensions after three consecutive leachings. The sequestration assays were performed at 20 °C with a flow rate of 5 mL/min of a CO2 concentration of 15.00 vol %. The results have revealed that the CO2 sequestration capacity of the LF slag suspension (24.7 g of CO2/100 g of slag) is 14 times superior to that of the EAF slag suspension. This greater CO2 sequestration capacity of the LF slag suspension may be associated in large part to its higher content of portlandite, which reacts with CO2 relative to the EAF slag suspension. Moreover, the separation of hydrated-matrixes and leachates significantly enhanced the CO2 sequestration capacity of EAF slag while a slight decrease was observed for the LF slags. This may be due to an obstruction of the CO2 binding sites of LF slag hydrated-matrixes following the accumulation of calcium carbonate. Taken together, these results suggest that EAF and LF slags could be used for the CO2 sequestration and given a good yield as well in aqueous suspension as in separated matrixes and leachates. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701721j
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7610-7616[article] CO2 sequestration potential of steel slags at ambient pressure and temperature [texte imprimé] / Danielle Bonenfant, Éditeur scientifique ; Lynda Kharoune, Éditeur scientifique ; Sébastien Sauve, Éditeur scientifique . - 2008 . - P. 7610-7616.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7610-7616
Mots-clés : Carbon dioxide Electric arc furnace (EAF) Ladle (LF) CO2 Résumé : A study of carbon dioxide sequestration has been performed in aqueous electric arc furnace (EAF) and ladle furnace (LF) slag suspensions, in leached hydrated-matrixes, and in leachates to estimate their intrinsic sequestration potential at ambient conditions (temperature of 20 ± 1 °C and atmospheric pressure). The CO2 sequestration was tested in aqueous suspensions of steel slags at a liquid-to-solid ratio of 10 kg/kg as well as in leached hydrated-matrixes and leachates isolated from these fresh slag suspensions after three consecutive leachings. The sequestration assays were performed at 20 °C with a flow rate of 5 mL/min of a CO2 concentration of 15.00 vol %. The results have revealed that the CO2 sequestration capacity of the LF slag suspension (24.7 g of CO2/100 g of slag) is 14 times superior to that of the EAF slag suspension. This greater CO2 sequestration capacity of the LF slag suspension may be associated in large part to its higher content of portlandite, which reacts with CO2 relative to the EAF slag suspension. Moreover, the separation of hydrated-matrixes and leachates significantly enhanced the CO2 sequestration capacity of EAF slag while a slight decrease was observed for the LF slags. This may be due to an obstruction of the CO2 binding sites of LF slag hydrated-matrixes following the accumulation of calcium carbonate. Taken together, these results suggest that EAF and LF slags could be used for the CO2 sequestration and given a good yield as well in aqueous suspension as in separated matrixes and leachates. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701721j Exemplaires
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Titre : CO2 sequestration by aqueous red mud carbonation at ambient pressure and temperature Type de document : texte imprimé Auteurs : Danielle Bonenfant, Éditeur scientifique ; Lynda Kharoune, Éditeur scientifique ; Sébastien Sauve, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7617-7622 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : CO2 Carbonation Liquid-to-solid Résumé : An analysis of carbonation was carried out with the aqueous fresh red mud suspension at a liquid-to-solid ratio of 10 kg/kg, as well as in the leached-hydrated matrixes and leachates isolated from this red mud suspension after three successive leachings, to evaluate their intrinsic carbonation potential at ambient conditions (temperature of 20 ± 1 °C and atmospheric pressure). The carbonation assays were performed at 20 °C using a CO2 concentration of 15.00 vol% at a flow rate of 5 mL/min. The red mud matrix has a great leaching capacity of Na−(hydr)oxide, which is the principal hydroxide that seems to be implicated in the carbonation of leachates that have half-carbonation capacity of red mud. Moreover, the carbonation of the red mud suspension also involves a portlandite-containing matrix. The carbonation of the red mud suspension and leachates implicates a complete neutralization of their content in Ca− and Na−(hydr)oxides. Although the leached hydrated-matrixes seem to be partially carbonated, it preserves a carbonation capacity near to that of leachate after three successive leachings. Moreover, three leached hydrated-matrixes and leachates have a carbonation capacity (7.09 g of CO2/100 g of red mud) higher than the carbonation capacity obtained for the red mud suspension, which is evaluated to 4.15 g of CO2/100 g of red mud. Taken together, these results suggest that the carbonation of the red mud may be enhanced by the use of leached hydrated-matrixes and leachates obtained from multiple leaching. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie7017228
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7617-7622[article] CO2 sequestration by aqueous red mud carbonation at ambient pressure and temperature [texte imprimé] / Danielle Bonenfant, Éditeur scientifique ; Lynda Kharoune, Éditeur scientifique ; Sébastien Sauve, Éditeur scientifique . - 2008 . - P. 7617-7622.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7617-7622
Mots-clés : CO2 Carbonation Liquid-to-solid Résumé : An analysis of carbonation was carried out with the aqueous fresh red mud suspension at a liquid-to-solid ratio of 10 kg/kg, as well as in the leached-hydrated matrixes and leachates isolated from this red mud suspension after three successive leachings, to evaluate their intrinsic carbonation potential at ambient conditions (temperature of 20 ± 1 °C and atmospheric pressure). The carbonation assays were performed at 20 °C using a CO2 concentration of 15.00 vol% at a flow rate of 5 mL/min. The red mud matrix has a great leaching capacity of Na−(hydr)oxide, which is the principal hydroxide that seems to be implicated in the carbonation of leachates that have half-carbonation capacity of red mud. Moreover, the carbonation of the red mud suspension also involves a portlandite-containing matrix. The carbonation of the red mud suspension and leachates implicates a complete neutralization of their content in Ca− and Na−(hydr)oxides. Although the leached hydrated-matrixes seem to be partially carbonated, it preserves a carbonation capacity near to that of leachate after three successive leachings. Moreover, three leached hydrated-matrixes and leachates have a carbonation capacity (7.09 g of CO2/100 g of red mud) higher than the carbonation capacity obtained for the red mud suspension, which is evaluated to 4.15 g of CO2/100 g of red mud. Taken together, these results suggest that the carbonation of the red mud may be enhanced by the use of leached hydrated-matrixes and leachates obtained from multiple leaching. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie7017228 Exemplaires
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Titre : Production of very pure hydrogen with simultaneous capture of carbon dioxide using the redox reactions of iron oxides in packed beds Type de document : texte imprimé Auteurs : Christopher D. Bohn, Éditeur scientifique ; Christoph R. Müller, Éditeur scientifique ; Jason P. Cleeton, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7623-7630 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hydrogen Carbon dioxide Oxides H2 CO2 Résumé : A chemical looping process, which uses a packed bed of the various oxides of iron, has been formulated to produce separate, pure streams of H2 and CO2 from syngas. The process has the following stages: (1) Reduction of Fe2O3 to Fe0.947O in the syngas from gasifying coal or biomass. This stage generates pure CO2, once the water has been condensed. (2) Subsequent oxidation of Fe0.947O to Fe3O4 using steam, to simultaneously produce H2. (3) Further oxidation of Fe3O4 to Fe2O3 using air to return the oxide to step 1. Step 1 was studied here using a mixture of CO + CO2 + N2 as the feed to a packed bed of iron oxide particles, while measuring the concentrations of CO and CO2 in the off-gas; step 2 was investigated by passing steam in N2 through the packed bed and measuring the quantity of H2 produced. The third step simply involved passing air through the bed. Reduction to Fe, rather than Fe0.947O, in step 1 gave low levels of H2 in step 2 after 10 cycles of reduction and oxidation and led to the deposition of carbon at lower temperature. Step 3, i.e. reoxidizing the particles in air to Fe2O3, led to no deterioration of the hydrogen yield in step 2 and benefited the process by (i) increasing the heat produced in each redox cycle and (ii) preventing the slip of CO from the bed in step 1. The proposed process is exothermic overall and very usefully generates separate streams of very pure H2 and CO2 without complicated separation units. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800335j
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7623-7630[article] Production of very pure hydrogen with simultaneous capture of carbon dioxide using the redox reactions of iron oxides in packed beds [texte imprimé] / Christopher D. Bohn, Éditeur scientifique ; Christoph R. Müller, Éditeur scientifique ; Jason P. Cleeton, Éditeur scientifique . - 2008 . - P. 7623-7630.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7623-7630
Mots-clés : Hydrogen Carbon dioxide Oxides H2 CO2 Résumé : A chemical looping process, which uses a packed bed of the various oxides of iron, has been formulated to produce separate, pure streams of H2 and CO2 from syngas. The process has the following stages: (1) Reduction of Fe2O3 to Fe0.947O in the syngas from gasifying coal or biomass. This stage generates pure CO2, once the water has been condensed. (2) Subsequent oxidation of Fe0.947O to Fe3O4 using steam, to simultaneously produce H2. (3) Further oxidation of Fe3O4 to Fe2O3 using air to return the oxide to step 1. Step 1 was studied here using a mixture of CO + CO2 + N2 as the feed to a packed bed of iron oxide particles, while measuring the concentrations of CO and CO2 in the off-gas; step 2 was investigated by passing steam in N2 through the packed bed and measuring the quantity of H2 produced. The third step simply involved passing air through the bed. Reduction to Fe, rather than Fe0.947O, in step 1 gave low levels of H2 in step 2 after 10 cycles of reduction and oxidation and led to the deposition of carbon at lower temperature. Step 3, i.e. reoxidizing the particles in air to Fe2O3, led to no deterioration of the hydrogen yield in step 2 and benefited the process by (i) increasing the heat produced in each redox cycle and (ii) preventing the slip of CO from the bed in step 1. The proposed process is exothermic overall and very usefully generates separate streams of very pure H2 and CO2 without complicated separation units. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800335j Exemplaires
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Titre : Heterogeneous approach to the catalytic cracking of vacuum gas oil Type de document : texte imprimé Auteurs : Mustafa Al-Sabawi, Éditeur scientifique ; Jesús A. Atias, Éditeur scientifique ; Hugo De Lasa, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7631-7641 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Gas Oil Zeolite catalysts Résumé : This study examines the roles of intracrystallite diffusion and reaction phenomena during the catalytic cracking of vacuum gas oil. Catalytic cracking experiments on FCC-type catalysts were performed in a fluidized bench-scale CREC riser simulator. This reactor was operated under close-to-industrial FCC conditions in terms of temperature, reaction time, partial pressures of reactant and products, and catalyst-to-oil ratio. The activity and selectivity of two USY zeolite catalysts, with very similar properties but varying zeolite crystallite sizes, were determined. A five-lump kinetic model describing the catalytic cracking of gas oil to light cycle oil, gasoline, light gases, and coke and accounting for diffusional constraints experienced by hydrocarbons while evolving in the zeolite pore network was considered. The results show that the catalyst with the smaller crystallites provided higher activity and selectivity toward desirable intermediate products (gasoline with low aromatics) and lower selectivity for terminal products (coke), indicating that diffusion plays a significant role in catalytic cracking. Diffusivity and kinetic parameters, including modified Thiele modulus and effectiveness factor, were established to determine the effects of crystallite size and temperature on the operating regime of the catalyst. It was found that, in the 510−530 °C range, the overall cracking rate is controlled by the highly temperature-sensitive intracrystalline gas oil transport, whereas in the 550−570 °C range, the overall cracking rate is dominated by a mildly temperature-sensitive intrinsic cracking rate. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701745k
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7631-7641[article] Heterogeneous approach to the catalytic cracking of vacuum gas oil [texte imprimé] / Mustafa Al-Sabawi, Éditeur scientifique ; Jesús A. Atias, Éditeur scientifique ; Hugo De Lasa, Éditeur scientifique . - 2008 . - P. 7631-7641.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7631-7641
Mots-clés : Gas Oil Zeolite catalysts Résumé : This study examines the roles of intracrystallite diffusion and reaction phenomena during the catalytic cracking of vacuum gas oil. Catalytic cracking experiments on FCC-type catalysts were performed in a fluidized bench-scale CREC riser simulator. This reactor was operated under close-to-industrial FCC conditions in terms of temperature, reaction time, partial pressures of reactant and products, and catalyst-to-oil ratio. The activity and selectivity of two USY zeolite catalysts, with very similar properties but varying zeolite crystallite sizes, were determined. A five-lump kinetic model describing the catalytic cracking of gas oil to light cycle oil, gasoline, light gases, and coke and accounting for diffusional constraints experienced by hydrocarbons while evolving in the zeolite pore network was considered. The results show that the catalyst with the smaller crystallites provided higher activity and selectivity toward desirable intermediate products (gasoline with low aromatics) and lower selectivity for terminal products (coke), indicating that diffusion plays a significant role in catalytic cracking. Diffusivity and kinetic parameters, including modified Thiele modulus and effectiveness factor, were established to determine the effects of crystallite size and temperature on the operating regime of the catalyst. It was found that, in the 510−530 °C range, the overall cracking rate is controlled by the highly temperature-sensitive intracrystalline gas oil transport, whereas in the 550−570 °C range, the overall cracking rate is dominated by a mildly temperature-sensitive intrinsic cracking rate. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701745k Exemplaires
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Titre : Simple synthesis, magnetic properties, and nonisothermal decomposition kinetics of Fe(H2PO4)2·2H2O Type de document : texte imprimé Auteurs : Banjong Boonchom, Éditeur scientifique ; Chanaiporn Danvirutai, Éditeur scientifique ; Sujittra Youngme, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7642-7647 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Iron metal Phosphoric acid Magnetic Properties Fe(H2PO4)2·2H2O Résumé : Fe(H2PO4)2·2H2O was synthesized by a simple and cost-effective method using iron metal and phosphoric acid as starting chemicals. The thermal transformation products from the synthesized Fe(H2PO4)2·2H2O according to the thermal treatment at 423 and 673 K were found to be FeH2P2O7 and Fe2P4O12, respectively. The activation energies of decomposition reaction of Fe(H2PO4)2·2H2O were calculated through the isoconversional methods of Ozawa and Kissinger−Akahira−Sunose. The synthesized Fe(H2PO4)2·2H2O and its thermal transformation products were characterized by scanning electron microscopy, X-ray powder diffraction, and FTIR spectroscopy. Room-temperature magnetization results showed a ferromagnetic behavior of the Fe(H2PO4)2·2H2O and its thermal transformation products. The hysteresis loops were in the range −10000 Oe En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800007j
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7642-7647[article] Simple synthesis, magnetic properties, and nonisothermal decomposition kinetics of Fe(H2PO4)2·2H2O [texte imprimé] / Banjong Boonchom, Éditeur scientifique ; Chanaiporn Danvirutai, Éditeur scientifique ; Sujittra Youngme, Éditeur scientifique . - 2008 . - P. 7642-7647.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7642-7647
Mots-clés : Iron metal Phosphoric acid Magnetic Properties Fe(H2PO4)2·2H2O Résumé : Fe(H2PO4)2·2H2O was synthesized by a simple and cost-effective method using iron metal and phosphoric acid as starting chemicals. The thermal transformation products from the synthesized Fe(H2PO4)2·2H2O according to the thermal treatment at 423 and 673 K were found to be FeH2P2O7 and Fe2P4O12, respectively. The activation energies of decomposition reaction of Fe(H2PO4)2·2H2O were calculated through the isoconversional methods of Ozawa and Kissinger−Akahira−Sunose. The synthesized Fe(H2PO4)2·2H2O and its thermal transformation products were characterized by scanning electron microscopy, X-ray powder diffraction, and FTIR spectroscopy. Room-temperature magnetization results showed a ferromagnetic behavior of the Fe(H2PO4)2·2H2O and its thermal transformation products. The hysteresis loops were in the range −10000 Oe En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800007j Exemplaires
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Titre : Hydrogenation of amino acid mixtures to amino alcohols Type de document : texte imprimé Auteurs : Ketan P. Pimparkar, Éditeur scientifique ; Dennis J. Miller, Éditeur scientifique ; James E. Jackson, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7648-7653 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Amino acid alcohols Résumé : Amino alcohols are important building blocks for a variety of pharmaceutical, insecticidal, and other specialty compounds. Hydrogenation of amino acids to amino alcohols is a route that allows for the incorporation of biorenewable-derived chemicals into traditional petroleum-based industrial processes. This study examines the effect of multiple substrates on aqueous-phase hydrogenation rates of the amino acids serine, alanine, and valine. Hydrogenation reactions were carried out in a high-pressure reactor at 7.0 MPa hydrogen pressure and 130 °C over carbon supported ruthenium catalyst. Samples taken at regular intervals and analyzed by high-performance liquid chromatography allowed calculation of conversion rates and product yields. In general, competition between the amino acid substrates results in reduced reaction rates relative to that for hydrogenation of a single amino acid substrate. Kinetics of mixed amino acid hydrogenation was modeled using a Langmuir−Hinshelwood-type mechanism with surface reaction as the rate-limiting step. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800351x
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7648-7653[article] Hydrogenation of amino acid mixtures to amino alcohols [texte imprimé] / Ketan P. Pimparkar, Éditeur scientifique ; Dennis J. Miller, Éditeur scientifique ; James E. Jackson, Éditeur scientifique . - 2008 . - P. 7648-7653.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7648-7653
Mots-clés : Amino acid alcohols Résumé : Amino alcohols are important building blocks for a variety of pharmaceutical, insecticidal, and other specialty compounds. Hydrogenation of amino acids to amino alcohols is a route that allows for the incorporation of biorenewable-derived chemicals into traditional petroleum-based industrial processes. This study examines the effect of multiple substrates on aqueous-phase hydrogenation rates of the amino acids serine, alanine, and valine. Hydrogenation reactions were carried out in a high-pressure reactor at 7.0 MPa hydrogen pressure and 130 °C over carbon supported ruthenium catalyst. Samples taken at regular intervals and analyzed by high-performance liquid chromatography allowed calculation of conversion rates and product yields. In general, competition between the amino acid substrates results in reduced reaction rates relative to that for hydrogenation of a single amino acid substrate. Kinetics of mixed amino acid hydrogenation was modeled using a Langmuir−Hinshelwood-type mechanism with surface reaction as the rate-limiting step. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800351x Exemplaires
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Titre : Comprehensive kinetic model for the degradation of methyl tert-butyl ether by an ozone/UV process Type de document : texte imprimé Auteurs : Temesgen Garoma, Éditeur scientifique ; Mirat D. Gurol, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7654-7662 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Methyl tert-Butyl Ether (MTBE) Ozone/UV Process ozone gas Résumé : The paper presents a comprehensive kinetic model that describes the degradation of methyl tert-butyl ether (MTBE) in an ozone/UV process. First, the degradation pathways for MTBE were proposed on the basis of major reaction intermediates identified during the oxidation of MTBE. The yield for each major reaction intermediate was determined by fitting experimental data to the model prediction. Accordingly, 43, 20, 15, 11, and 6% of MTBE oxidized resulted in the generation of TBF, MMP, TBA, acetone, and methyl acetate, respectively. TBF oxidation resulted in the generation of HiBA, acetone, and TBA as primary intermediates at 47, 24, and 20%, respectively. During the oxidation of TBA, 66% resulted in the generation of HiBA and 34% in acetone. The kinetic model was verified using different sets of experimental data by varying the initial concentration of MTBE, influent ozone gas concentration, and incident UV light intensity. The model predicted well the degradation of MTBE by an ozone/UV process. In addition, the model predicted the accumulation and decay of primary intermediates (TBF, TBA, MMP, methyl acetate, and acetone) with slight variations. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800721t
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7654-7662[article] Comprehensive kinetic model for the degradation of methyl tert-butyl ether by an ozone/UV process [texte imprimé] / Temesgen Garoma, Éditeur scientifique ; Mirat D. Gurol, Éditeur scientifique . - 2008 . - P. 7654-7662.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7654-7662
Mots-clés : Methyl tert-Butyl Ether (MTBE) Ozone/UV Process ozone gas Résumé : The paper presents a comprehensive kinetic model that describes the degradation of methyl tert-butyl ether (MTBE) in an ozone/UV process. First, the degradation pathways for MTBE were proposed on the basis of major reaction intermediates identified during the oxidation of MTBE. The yield for each major reaction intermediate was determined by fitting experimental data to the model prediction. Accordingly, 43, 20, 15, 11, and 6% of MTBE oxidized resulted in the generation of TBF, MMP, TBA, acetone, and methyl acetate, respectively. TBF oxidation resulted in the generation of HiBA, acetone, and TBA as primary intermediates at 47, 24, and 20%, respectively. During the oxidation of TBA, 66% resulted in the generation of HiBA and 34% in acetone. The kinetic model was verified using different sets of experimental data by varying the initial concentration of MTBE, influent ozone gas concentration, and incident UV light intensity. The model predicted well the degradation of MTBE by an ozone/UV process. In addition, the model predicted the accumulation and decay of primary intermediates (TBF, TBA, MMP, methyl acetate, and acetone) with slight variations. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800721t Exemplaires
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Titre : Partial oxidation of n-tetradecane over 1 wt % Pt/γ-Al2O3 and Co0.4Mo0.6Cx carbide catalysts : a comparative study Type de document : texte imprimé Auteurs : Daniel J. Haynes, Éditeur scientifique ; David A. Berry, Éditeur scientifique ; Dushyant Shekhawat, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7663-7671 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Catalytic partial oxidation (CPOX) Carbide Catalysts Dibenzothiophene (DBT) 1-Methylnaphthalene (1-MN) Résumé : Catalytic partial oxidation (CPOX) of liquid fuels is being widely studied as an option for producing a hydrogen-rich gas stream for fuel cells. However, deactivation of catalysts by carbon deposition and sulfur poisoning in this process is a key technical challenge. Here, the deactivation of Co0.4Mo0.6Cx has been compared to that of 1 wt % Pt/γ-Al2O3 in a fixed-bed catalytic reactor, using mixtures of n-tetradecane and either 1-methylnaphthalene (1-MN) or dibenzothiophene (DBT) to simulate diesel fuel. The results show that Co0.4Mo0.6Cx is stable and active for the CPOX of n-tetradecane at 850 °C, 50000 scc/(gcat h), and an O/C ratio of 1.2. This catalyst produces slightly lower H2 and CO yields than Pt/γ-Al2O3, but still close to equilibrium values for 5 h. A low concentration of sulfur (50 ppmw as DBT) has little effect on either activity or selectivity for the carbide or Pt/γ-Al2O3 catalyst. However, the presence of 1-MN or a high sulfur concentration (1000 ppmw as DBT) deactivates both catalysts, resulting in reaction products that are typical of gas-phase reactions in a blank reactor. The addition of 1-MN or 1000 ppmw DBT to n-tetradecane produces qualitatively similar results on both catalysts: H2 production decreases continuously in the presence of either 1-MN or DBT, and CO drops to a stationary level. This drop in synthesis gas yields corresponds to an increase in steam, CO2, and olefin yields, suggesting that the contaminants deactivate sites that are active for steam and dry reforming reactions downstream of the reactor inlet, where rapid oxidation takes place. Once the contaminants are removed, initial activity returns more quickly for the carbide than for Pt/γ-Al2O3. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071295t
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7663-7671[article] Partial oxidation of n-tetradecane over 1 wt % Pt/γ-Al2O3 and Co0.4Mo0.6Cx carbide catalysts : a comparative study [texte imprimé] / Daniel J. Haynes, Éditeur scientifique ; David A. Berry, Éditeur scientifique ; Dushyant Shekhawat, Éditeur scientifique . - 2008 . - P. 7663-7671.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7663-7671
Mots-clés : Catalytic partial oxidation (CPOX) Carbide Catalysts Dibenzothiophene (DBT) 1-Methylnaphthalene (1-MN) Résumé : Catalytic partial oxidation (CPOX) of liquid fuels is being widely studied as an option for producing a hydrogen-rich gas stream for fuel cells. However, deactivation of catalysts by carbon deposition and sulfur poisoning in this process is a key technical challenge. Here, the deactivation of Co0.4Mo0.6Cx has been compared to that of 1 wt % Pt/γ-Al2O3 in a fixed-bed catalytic reactor, using mixtures of n-tetradecane and either 1-methylnaphthalene (1-MN) or dibenzothiophene (DBT) to simulate diesel fuel. The results show that Co0.4Mo0.6Cx is stable and active for the CPOX of n-tetradecane at 850 °C, 50000 scc/(gcat h), and an O/C ratio of 1.2. This catalyst produces slightly lower H2 and CO yields than Pt/γ-Al2O3, but still close to equilibrium values for 5 h. A low concentration of sulfur (50 ppmw as DBT) has little effect on either activity or selectivity for the carbide or Pt/γ-Al2O3 catalyst. However, the presence of 1-MN or a high sulfur concentration (1000 ppmw as DBT) deactivates both catalysts, resulting in reaction products that are typical of gas-phase reactions in a blank reactor. The addition of 1-MN or 1000 ppmw DBT to n-tetradecane produces qualitatively similar results on both catalysts: H2 production decreases continuously in the presence of either 1-MN or DBT, and CO drops to a stationary level. This drop in synthesis gas yields corresponds to an increase in steam, CO2, and olefin yields, suggesting that the contaminants deactivate sites that are active for steam and dry reforming reactions downstream of the reactor inlet, where rapid oxidation takes place. Once the contaminants are removed, initial activity returns more quickly for the carbide than for Pt/γ-Al2O3. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071295t Exemplaires
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Titre : Effects of feed composition and space velocity on direct synthesis of dimethyl ether from syngas Type de document : texte imprimé Auteurs : Gholamreza Moradi, Éditeur scientifique ; Javad Ahmadpour, Éditeur scientifique ; Mahdi Nazari, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7672-7679 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Feed composition Space velocity Bifunctional catalyst (CuO/ZnO/Al2O3+ H-ZSM-5) Résumé : Full factorial experimental design method was applied for investigation of the effects of different space velocity (SV) (500−1500 mLn/(g-cat.h)) and H2/CO molar feed ratio (1−2) on CO conversion and/or DME selectivity as the response variables over a physically prepared bifunctional catalyst (CuO/ZnO/Al2O3+ H-ZSM-5) for liquid phase direct DME synthesis from synthesis gas. The results showed that feed composition is the more effective factor on the response and the interaction of the SV and H2/CO only slightly influenced the response. The factor levels that can maximize the SDME are SV of 1500 mLn/(g-cat.h) and H2/CO of 1.5 at 240 °C and 35 bar. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800888z
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7672-7679[article] Effects of feed composition and space velocity on direct synthesis of dimethyl ether from syngas [texte imprimé] / Gholamreza Moradi, Éditeur scientifique ; Javad Ahmadpour, Éditeur scientifique ; Mahdi Nazari, Éditeur scientifique . - 2008 . - P. 7672-7679.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7672-7679
Mots-clés : Feed composition Space velocity Bifunctional catalyst (CuO/ZnO/Al2O3+ H-ZSM-5) Résumé : Full factorial experimental design method was applied for investigation of the effects of different space velocity (SV) (500−1500 mLn/(g-cat.h)) and H2/CO molar feed ratio (1−2) on CO conversion and/or DME selectivity as the response variables over a physically prepared bifunctional catalyst (CuO/ZnO/Al2O3+ H-ZSM-5) for liquid phase direct DME synthesis from synthesis gas. The results showed that feed composition is the more effective factor on the response and the interaction of the SV and H2/CO only slightly influenced the response. The factor levels that can maximize the SDME are SV of 1500 mLn/(g-cat.h) and H2/CO of 1.5 at 240 °C and 35 bar. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800888z Exemplaires
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Titre : Controlled synthesis of monolithic hierarchical porous materials using wood as a template with assistance of supercritical carbon dioxide Type de document : texte imprimé Auteurs : Jianbo Li, Éditeur scientifique ; Jiguang Wang, Éditeur scientifique ; Jianxia Jiao, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7680-7685 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Carbon Dioxide Monolithic porous inorganic materials CO2 Résumé : A green and efficient process to synthesize monolithic porous inorganic materials with hierarchical structure has been presented. By using wood cellular structure as a template and supercritical CO2 as a solvent and carrier, the morphology and pore or channel systems of wood templates could be replicated faithfully. The total BET (Brunauer−Emmett−Teller) surface area of the resulting silica material can reach 469 m2/g using poplar as the template. It is found that different pore structure data can be obtained with different wood cellular structures as the template. Meanwhile, the pore structure data of the product can be adjusted by changing the experimental conditions of the supercritical CO2 during the impregnation process. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0711269
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7680-7685[article] Controlled synthesis of monolithic hierarchical porous materials using wood as a template with assistance of supercritical carbon dioxide [texte imprimé] / Jianbo Li, Éditeur scientifique ; Jiguang Wang, Éditeur scientifique ; Jianxia Jiao, Éditeur scientifique . - 2008 . - P. 7680-7685.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7680-7685
Mots-clés : Carbon Dioxide Monolithic porous inorganic materials CO2 Résumé : A green and efficient process to synthesize monolithic porous inorganic materials with hierarchical structure has been presented. By using wood cellular structure as a template and supercritical CO2 as a solvent and carrier, the morphology and pore or channel systems of wood templates could be replicated faithfully. The total BET (Brunauer−Emmett−Teller) surface area of the resulting silica material can reach 469 m2/g using poplar as the template. It is found that different pore structure data can be obtained with different wood cellular structures as the template. Meanwhile, the pore structure data of the product can be adjusted by changing the experimental conditions of the supercritical CO2 during the impregnation process. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0711269 Exemplaires
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Titre : Process parameter interaction effects during carbon nanotube synthesis in fluidized beds Type de document : texte imprimé Auteurs : Chee Howe See, Éditeur scientifique ; Oscar M. Dunens, Éditeur scientifique ; Kieran J. MacKenzie, Éditeur scientifique Année de publication : 2008 Article en page(s) : P. 7686-7692 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Carbon nanotube (CNT) Résumé : The interaction effects between temperature, catalyst properties, fluidization conditions, and deposition time during carbon nanotube (CNT) synthesis by chemical vapor deposition in a fluidized bed were investigated. While numerous investigations have attempted to correlate process parameters with CNT characteristics, selectivity and yield, the interaction between process parameters is often ignored. Parametric interactions in this process have been investigated using a factorial design methodology. Besides the main effects of synthesis temperature, deposition time, and catalyst type, the interaction parameters temperature−time and temperature−catalyst were found to significantly influence the resultant carbon and CNT yields. These results lay the foundation for a detailed parametric analysis toward the optimization of CNT synthesis in fluidized beds, which takes into account these interaction effects. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701786p
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7686-7692[article] Process parameter interaction effects during carbon nanotube synthesis in fluidized beds [texte imprimé] / Chee Howe See, Éditeur scientifique ; Oscar M. Dunens, Éditeur scientifique ; Kieran J. MacKenzie, Éditeur scientifique . - 2008 . - P. 7686-7692.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7686-7692
Mots-clés : Carbon nanotube (CNT) Résumé : The interaction effects between temperature, catalyst properties, fluidization conditions, and deposition time during carbon nanotube (CNT) synthesis by chemical vapor deposition in a fluidized bed were investigated. While numerous investigations have attempted to correlate process parameters with CNT characteristics, selectivity and yield, the interaction between process parameters is often ignored. Parametric interactions in this process have been investigated using a factorial design methodology. Besides the main effects of synthesis temperature, deposition time, and catalyst type, the interaction parameters temperature−time and temperature−catalyst were found to significantly influence the resultant carbon and CNT yields. These results lay the foundation for a detailed parametric analysis toward the optimization of CNT synthesis in fluidized beds, which takes into account these interaction effects. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701786p Exemplaires
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Titre : Microstructural modeling of solid oxide fuel cell anodes Type de document : texte imprimé Auteurs : Joshua Golbert, Auteur ; Adjiman, Claire S., Auteur ; Nigel P. Brandon, Auteur Année de publication : 2008 Article en page(s) : P. 7693-7699 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Solid Oxide Fuel Cell (SOFC) Electrodes SOFC Résumé : The design and manufacture of electrodes for use in SOFCs is one of the greatest challenges to the commercialization of fuel cell technology. Composite SOFC electrodes mix three phases (ion conducting, electron conducting, pore phase) in order to improve performance by increasing the amount of triple-phase boundaries (TBPs)—meetings of the ionic and electronic pathways with the percolating gas network—where the redox reaction takes place. The electrode microstructure is critical since electrode performance is directly dependent on the abundance of TPBs and the transport properties of the three phases.A fundamental understanding of the quantitative effects of microstructure on electrode performance is required. However, electrode models commonly neglect heterogeneity and assume effective values for key parameters. In contrast, we present a computational framework that can readily be linked to experimental studies of microstructure, thereby providing crucial insight into the conditions and competing processes in the porous microstructure, insight that can be used to design future generations of electrodes. In the proposed methodology, a virtual electrode is generated by randomly placing spherical particles in a packed bed. The particles are then expanded to simulate sintering to ensure large contact surfaces between the different phases. Once the porous structure is obtained, we can analyze the porosity and percolation of the various phases and the amount of triple-phase boundary and its percolation throughout the electrode. Furthermore, the transport and redox phenomena are also modeled to determine the potential, current, and chemical distribution throughout the different phases. We are then able to predict electrode performance based on fundamental properties of the underlying microstructure. These results are used to relate microstructural properties to electrode performance. The microstructural properties can include porosity, particle radii, and radius ratio and the effect of graded electrodes. The method is tested on model systems and used to demonstrate the effect of particle size on performance. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800065w
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7693-7699[article] Microstructural modeling of solid oxide fuel cell anodes [texte imprimé] / Joshua Golbert, Auteur ; Adjiman, Claire S., Auteur ; Nigel P. Brandon, Auteur . - 2008 . - P. 7693-7699.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7693-7699
Mots-clés : Solid Oxide Fuel Cell (SOFC) Electrodes SOFC Résumé : The design and manufacture of electrodes for use in SOFCs is one of the greatest challenges to the commercialization of fuel cell technology. Composite SOFC electrodes mix three phases (ion conducting, electron conducting, pore phase) in order to improve performance by increasing the amount of triple-phase boundaries (TBPs)—meetings of the ionic and electronic pathways with the percolating gas network—where the redox reaction takes place. The electrode microstructure is critical since electrode performance is directly dependent on the abundance of TPBs and the transport properties of the three phases.A fundamental understanding of the quantitative effects of microstructure on electrode performance is required. However, electrode models commonly neglect heterogeneity and assume effective values for key parameters. In contrast, we present a computational framework that can readily be linked to experimental studies of microstructure, thereby providing crucial insight into the conditions and competing processes in the porous microstructure, insight that can be used to design future generations of electrodes. In the proposed methodology, a virtual electrode is generated by randomly placing spherical particles in a packed bed. The particles are then expanded to simulate sintering to ensure large contact surfaces between the different phases. Once the porous structure is obtained, we can analyze the porosity and percolation of the various phases and the amount of triple-phase boundary and its percolation throughout the electrode. Furthermore, the transport and redox phenomena are also modeled to determine the potential, current, and chemical distribution throughout the different phases. We are then able to predict electrode performance based on fundamental properties of the underlying microstructure. These results are used to relate microstructural properties to electrode performance. The microstructural properties can include porosity, particle radii, and radius ratio and the effect of graded electrodes. The method is tested on model systems and used to demonstrate the effect of particle size on performance. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800065w Exemplaires
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Titre : Fe3O4/poly(N-Isopropylacrylamide)/chitosan composite microspheres with multiresponsive properties Type de document : texte imprimé Auteurs : Pei Li, Auteur ; Ai Mei Zhu, Auteur ; Qing Lin Liu, Auteur ; Qiu Gen Zhang, Auteur Année de publication : 2008 Article en page(s) : P. 7700-7706 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Multiresponsive Fourier transform infrared spectroscopy (FTIR) X-ray diffraction (XRD) Thermogravimetric analysis (TGA) Scanning electron microscopy (SEM) Transmission electronic (TEM) Résumé : Multiresponsive composite microspheres were fabricated via emulsion polymerization in two steps. Fe3O4 nanoparticles modified by oleic acid (about 13 nm in diameter) were first prepared, and then they were embedded in biocompatible chitosan (CS) and N-isopropylacrylamide (NIPAm). Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) examined the structure and morphology of the composite microspheres. Scanning electron microscopy (SEM) and transmission electronic microscopy (TEM) indicate the diameter of the composite microspheres to be about 400 nm. The magnetic, thermo, and pH-sensitive properties of the composite microspheres were investigated. Magnetic measurements with magnet and superconducting quantum interference device (SQUID) reveal that the composite microspheres are superparamagnetic. The electromagnetically induced heating shows that the composite microspheres could be heated up to 45 °C in an alternating electromagnetic field. The dynamic light scattering (DLS) results confirm the thermoresponsive and pH-responsive properties. It was found that the lower critical solution temperature (LCST) of the composite microspheres is 29 °C in water, and the LCST changed from 28 to 32 °C in the pH range from 4.7 to 7.4. These composite microspheres with the multiresponsive properties show great promise in biomedical applications. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800824q
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7700-7706[article] Fe3O4/poly(N-Isopropylacrylamide)/chitosan composite microspheres with multiresponsive properties [texte imprimé] / Pei Li, Auteur ; Ai Mei Zhu, Auteur ; Qing Lin Liu, Auteur ; Qiu Gen Zhang, Auteur . - 2008 . - P. 7700-7706.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7700-7706
Mots-clés : Multiresponsive Fourier transform infrared spectroscopy (FTIR) X-ray diffraction (XRD) Thermogravimetric analysis (TGA) Scanning electron microscopy (SEM) Transmission electronic (TEM) Résumé : Multiresponsive composite microspheres were fabricated via emulsion polymerization in two steps. Fe3O4 nanoparticles modified by oleic acid (about 13 nm in diameter) were first prepared, and then they were embedded in biocompatible chitosan (CS) and N-isopropylacrylamide (NIPAm). Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) examined the structure and morphology of the composite microspheres. Scanning electron microscopy (SEM) and transmission electronic microscopy (TEM) indicate the diameter of the composite microspheres to be about 400 nm. The magnetic, thermo, and pH-sensitive properties of the composite microspheres were investigated. Magnetic measurements with magnet and superconducting quantum interference device (SQUID) reveal that the composite microspheres are superparamagnetic. The electromagnetically induced heating shows that the composite microspheres could be heated up to 45 °C in an alternating electromagnetic field. The dynamic light scattering (DLS) results confirm the thermoresponsive and pH-responsive properties. It was found that the lower critical solution temperature (LCST) of the composite microspheres is 29 °C in water, and the LCST changed from 28 to 32 °C in the pH range from 4.7 to 7.4. These composite microspheres with the multiresponsive properties show great promise in biomedical applications. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800824q Exemplaires
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Titre : Sulfonation of surface-initiated polynorbornene films Type de document : texte imprimé Auteurs : Brad J. Berron, Auteur ; Andrew P. Payne, Auteur ; Kane G. Jennings, Auteur Année de publication : 2008 Article en page(s) : P. 7707-7714 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : polynorbornene self-assembled monolayer (SAM) ring-opening metathesis polymerization (ROMP) Résumé : We report the sulfonation of surface-initiated polynorbornene with acetyl sulfate to produce ultrathin ionomer films. The complete process consists of exposure of a hydroxyl-terminated self-assembled monolayer (SAM) on gold to a norbornenyl diacid chloride, attachment of Grubbs first generation catalyst, ring-opening metathesis polymerization (ROMP), and sulfonation. Structural and chemical changes in the film upon sulfonation are confirmed by RAIRS, contact angle goniometry, ellipsometry, optical microscopy, and electrochemical impedance spectroscopy. Sulfonation of surface-initiated polynorbornene results in a highly nonuniform surface morphology which can be relaxed to a more uniform film through exposure to dimethyl sulfoxide at room temperature. The sulfonated polynorbornene films have an intermediate surface energy (θA(H2O) ≈ 75°) and a low resistance against proton transport (Rf ≈ 1.6 Ω·cm2), which is 6 orders of magnitude lower than that of the original polynorbornene film. The sulfonated films are far more stable than the original polynorbornene films because of a ∼95% diminution of olefin content within the film. Sulfonated poly(butylnorbornene) films were prepared analogously to demonstrate the versatility of this approach toward ionomer films. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800356a
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7707-7714[article] Sulfonation of surface-initiated polynorbornene films [texte imprimé] / Brad J. Berron, Auteur ; Andrew P. Payne, Auteur ; Kane G. Jennings, Auteur . - 2008 . - P. 7707-7714.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7707-7714
Mots-clés : polynorbornene self-assembled monolayer (SAM) ring-opening metathesis polymerization (ROMP) Résumé : We report the sulfonation of surface-initiated polynorbornene with acetyl sulfate to produce ultrathin ionomer films. The complete process consists of exposure of a hydroxyl-terminated self-assembled monolayer (SAM) on gold to a norbornenyl diacid chloride, attachment of Grubbs first generation catalyst, ring-opening metathesis polymerization (ROMP), and sulfonation. Structural and chemical changes in the film upon sulfonation are confirmed by RAIRS, contact angle goniometry, ellipsometry, optical microscopy, and electrochemical impedance spectroscopy. Sulfonation of surface-initiated polynorbornene results in a highly nonuniform surface morphology which can be relaxed to a more uniform film through exposure to dimethyl sulfoxide at room temperature. The sulfonated polynorbornene films have an intermediate surface energy (θA(H2O) ≈ 75°) and a low resistance against proton transport (Rf ≈ 1.6 Ω·cm2), which is 6 orders of magnitude lower than that of the original polynorbornene film. The sulfonated films are far more stable than the original polynorbornene films because of a ∼95% diminution of olefin content within the film. Sulfonated poly(butylnorbornene) films were prepared analogously to demonstrate the versatility of this approach toward ionomer films. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800356a Exemplaires
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Titre : Robust control of volatile fatty acids in anaerobic digestion processes Type de document : texte imprimé Auteurs : Hugo O. Mendez-Acosta, Auteur ; Bernardo Palacios-Ruiz, Auteur ; Victor Alcaraz-Gonzalez, Auteur ; Jean-Philippe Steyer, Auteur Année de publication : 2008 Article en page(s) : P. 7715-7720 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : volatile fatty acids (VFA) Anaerobic digestion processes Résumé : This paper is focused on the experimental implementation of a robust control scheme for the regulation of volatile fatty acids (VFA) in continuous anaerobic digestion processes. The robust scheme is made of an output feedback control, and an extended Luenberger observer is used to estimate the uncertain terms of the process (i.e., influent concentration and process kinetics). The control scheme is implemented in a pilot plant up-flow fixed-bed reactor that is treating industrial wine distillery wastewater. The performance of the robust scheme is tested over a period of 36 days, under different set-point values and several uncertain scenarios, including model mismatch, badly known parameters, and load disturbances. Experimental results show that the VFA concentration can be effectively regulated over a wide range of operating conditions. In addition, it is shown that the control scheme has a structure that improves its performance in the presence of noisy measurements and control input saturations. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800256e
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7715-7720[article] Robust control of volatile fatty acids in anaerobic digestion processes [texte imprimé] / Hugo O. Mendez-Acosta, Auteur ; Bernardo Palacios-Ruiz, Auteur ; Victor Alcaraz-Gonzalez, Auteur ; Jean-Philippe Steyer, Auteur . - 2008 . - P. 7715-7720.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7715-7720
Mots-clés : volatile fatty acids (VFA) Anaerobic digestion processes Résumé : This paper is focused on the experimental implementation of a robust control scheme for the regulation of volatile fatty acids (VFA) in continuous anaerobic digestion processes. The robust scheme is made of an output feedback control, and an extended Luenberger observer is used to estimate the uncertain terms of the process (i.e., influent concentration and process kinetics). The control scheme is implemented in a pilot plant up-flow fixed-bed reactor that is treating industrial wine distillery wastewater. The performance of the robust scheme is tested over a period of 36 days, under different set-point values and several uncertain scenarios, including model mismatch, badly known parameters, and load disturbances. Experimental results show that the VFA concentration can be effectively regulated over a wide range of operating conditions. In addition, it is shown that the control scheme has a structure that improves its performance in the presence of noisy measurements and control input saturations. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800256e Exemplaires
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Titre : Material Transfer Operations in Batch Scheduling : a critical modeling issue Type de document : texte imprimé Auteurs : Sergio Ferrer-Nadal, Auteur ; Elisabet Capon-Garcia, Auteur ; Carlos A. Méndez, Auteur ; Puigjaner, Luis, Auteur Année de publication : 2008 Article en page(s) : P. 7721-7732 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Batch Scheduling mixed-integer linear programming (MILP) Résumé : An effective short-term scheduling formulation must simultaneously deal with several problem difficulties commonly arising in batch processes operations. One of the key features to be considered is the representation of the material transfer operations between process stages. A nonzero time as well as certain conditions and resources are always required to move the material from one processing stage to the next one according to the specified product recipe. The transfer task consumes a period of time during which a proper synchronization of the equipment units supplying and receiving the material is enforced. Synchronization implies that during the execution of the transfer task, one unit will be supplying the material whereas the other one will be receiving it and consequently, no other task can be simultaneously performed in both units. Most of the existing mixed-integer linear programming (MILP) optimization approaches have traditionally dealt with the batch scheduling problem assuming zero transfer times, and consequently no synchronization, between consecutive processing stages. Simplification relying on negligible transfer times may work properly for the scheduling of multiproduct batch plants with similar product recipes; however, it is demonstrated in this work that ignoring the important role of transfer times may seriously compromise the feasibility of the scheduling whenever shared units and storage tanks, material recycles, or bidirectional flows of products are to be considered. To overcome the serious limitations of current MILP-based scheduling approaches, a general precedence-based framework accounting for nonzero transfer times is introduced. Also, two alternative methods that avoid generating unfeasible schedules are proposed and tested in different case studies. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800075u
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7721-7732[article] Material Transfer Operations in Batch Scheduling : a critical modeling issue [texte imprimé] / Sergio Ferrer-Nadal, Auteur ; Elisabet Capon-Garcia, Auteur ; Carlos A. Méndez, Auteur ; Puigjaner, Luis, Auteur . - 2008 . - P. 7721-7732.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7721-7732
Mots-clés : Batch Scheduling mixed-integer linear programming (MILP) Résumé : An effective short-term scheduling formulation must simultaneously deal with several problem difficulties commonly arising in batch processes operations. One of the key features to be considered is the representation of the material transfer operations between process stages. A nonzero time as well as certain conditions and resources are always required to move the material from one processing stage to the next one according to the specified product recipe. The transfer task consumes a period of time during which a proper synchronization of the equipment units supplying and receiving the material is enforced. Synchronization implies that during the execution of the transfer task, one unit will be supplying the material whereas the other one will be receiving it and consequently, no other task can be simultaneously performed in both units. Most of the existing mixed-integer linear programming (MILP) optimization approaches have traditionally dealt with the batch scheduling problem assuming zero transfer times, and consequently no synchronization, between consecutive processing stages. Simplification relying on negligible transfer times may work properly for the scheduling of multiproduct batch plants with similar product recipes; however, it is demonstrated in this work that ignoring the important role of transfer times may seriously compromise the feasibility of the scheduling whenever shared units and storage tanks, material recycles, or bidirectional flows of products are to be considered. To overcome the serious limitations of current MILP-based scheduling approaches, a general precedence-based framework accounting for nonzero transfer times is introduced. Also, two alternative methods that avoid generating unfeasible schedules are proposed and tested in different case studies. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800075u Exemplaires
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Titre : A TSP-based MILP model for medium-term planning of single-stage continuous multiproduct plants Type de document : texte imprimé Auteurs : Songsong Liu, Auteur ; Jose M. Pinto, Auteur ; Lazaros G. Papageorgiou, Auteur Année de publication : 2008 Article en page(s) : P. 7733-7743 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : mixed-integer linear programming (MILP)Plants Résumé : In this paper, we consider the problem of medium-term planning of single-stage continuous plants with a single processing unit that manufactures several products over a planning horizon of several weeks. Sequence-dependent changeover times and costs occur when switching from one type of product to another. To overcome the computational expensiveness of traditional slot-based models for large instances, a novel TSP-based (traveling salesman problem) mixed-integer linear programming (MILP) model is proposed that relies on a hybrid discrete/continuous time representation. The model is applied to an example of a real world polymer processing plant to illustrate its applicability. Finally, the proposed model is compared to recently published approaches through literature examples, and the results show that the computational performance of the proposed model is superior. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800646q
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7733-7743[article] A TSP-based MILP model for medium-term planning of single-stage continuous multiproduct plants [texte imprimé] / Songsong Liu, Auteur ; Jose M. Pinto, Auteur ; Lazaros G. Papageorgiou, Auteur . - 2008 . - P. 7733-7743.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7733-7743
Mots-clés : mixed-integer linear programming (MILP)Plants Résumé : In this paper, we consider the problem of medium-term planning of single-stage continuous plants with a single processing unit that manufactures several products over a planning horizon of several weeks. Sequence-dependent changeover times and costs occur when switching from one type of product to another. To overcome the computational expensiveness of traditional slot-based models for large instances, a novel TSP-based (traveling salesman problem) mixed-integer linear programming (MILP) model is proposed that relies on a hybrid discrete/continuous time representation. The model is applied to an example of a real world polymer processing plant to illustrate its applicability. Finally, the proposed model is compared to recently published approaches through literature examples, and the results show that the computational performance of the proposed model is superior. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800646q Exemplaires
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Titre : Multivariate temporal data analysis using self-organizing maps. 1. Training methodology for effective visualization of multistate operations Type de document : texte imprimé Auteurs : Yew Seng Ng, Auteur ; Rajagopalan Srinivasan, Auteur Année de publication : 2008 Article en page(s) : p. 7744-7757 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Self-organizing map (SOM) Multivariate temporal data analysis Résumé : Multistate operations are common in chemical plants and result in high-dimensional, multivariate, temporal data. In this two-part paper, we develop self-organizing map (SOM)-based approaches for visualizing and analyzing such data. In Part 1 of this paper, the SOM is used to reduce the dimensionality of the data and effectively visualize multistate operations in a three-dimensional map. A key characteristic of multistate processes is that the plant operates for long durations at steady states and undergoes brief transitions involving large changes in variable values. When classical SOM training algorithms are used on data from multistate processes, large portions of the SOM become dedicated to steady states, which exaggerates even minor noise in the data. Also, transitions are represented as discrete jumps on the SOM space, which makes it an ineffective tool for visualizing multistate operations. In this Part 1, we propose a new training strategy specifically targeted at multistate operations. In the proposed strategy, the training dataset is first resampled to yield equal representation of the different process states. The SOM is trained with this state-sampled dataset. Furthermore, clustering is applied to group neurons of high similarity into compact clusters. Through this strategy, modes and transitions of multistate operations are depicted differently, with process modes visualized as intuitive clusters and transitions as trajectories across the SOM. We illustrate the proposed strategy using two real-case studies, namely, startup of a laboratory-scale distillation unit and operation of a refinery hydrocracker. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0710216
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - p. 7744-7757[article] Multivariate temporal data analysis using self-organizing maps. 1. Training methodology for effective visualization of multistate operations [texte imprimé] / Yew Seng Ng, Auteur ; Rajagopalan Srinivasan, Auteur . - 2008 . - p. 7744-7757.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - p. 7744-7757
Mots-clés : Self-organizing map (SOM) Multivariate temporal data analysis Résumé : Multistate operations are common in chemical plants and result in high-dimensional, multivariate, temporal data. In this two-part paper, we develop self-organizing map (SOM)-based approaches for visualizing and analyzing such data. In Part 1 of this paper, the SOM is used to reduce the dimensionality of the data and effectively visualize multistate operations in a three-dimensional map. A key characteristic of multistate processes is that the plant operates for long durations at steady states and undergoes brief transitions involving large changes in variable values. When classical SOM training algorithms are used on data from multistate processes, large portions of the SOM become dedicated to steady states, which exaggerates even minor noise in the data. Also, transitions are represented as discrete jumps on the SOM space, which makes it an ineffective tool for visualizing multistate operations. In this Part 1, we propose a new training strategy specifically targeted at multistate operations. In the proposed strategy, the training dataset is first resampled to yield equal representation of the different process states. The SOM is trained with this state-sampled dataset. Furthermore, clustering is applied to group neurons of high similarity into compact clusters. Through this strategy, modes and transitions of multistate operations are depicted differently, with process modes visualized as intuitive clusters and transitions as trajectories across the SOM. We illustrate the proposed strategy using two real-case studies, namely, startup of a laboratory-scale distillation unit and operation of a refinery hydrocracker. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0710216 Exemplaires
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Titre : Multivariate temporal data analysis using self-organizing maps. 2. Monitoring and diagnosis of multistate operations Type de document : texte imprimé Auteurs : Yew Seng Ng, Auteur ; Rajagopalan Srinivasan, Auteur Année de publication : 2008 Article en page(s) : P. 7758-7771 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Self-organizing map (SOM) Multivariate temporal data analysis Résumé : The operation of transitions in continuous processes is challenging and often results in out-of-spec products, alarm floods, and abnormal situations. Therefore, efficient techniques for automated monitoring and fault diagnosis of such operations are essential. In Part 1 of this paper, we proposed a self-organizing map (SOM) training strategy for effectively visualizing multistate operations. In this part of the series, we use the same methodology as a representation scheme to compare operating trajectories and diagnosing faults during transient operations. In the proposed approach, clusters of SOM neurons, called neuronal clusters, serve as landmarks on the multivariate measurement space. Online data during the transition are reflected as a trajectory on the SOM and are converted to a sequence of neuronal clusters, which are the signature of the operating state. We have adapted the well-known Smith and Waterman discrete sequence comparison algorithm from bioinformatics to compare the state signatures and account for run-to-run variations. The proposed comparison method accounts explicitly for oscillations that are common in chemical processes. Online monitoring and diagnosis is performed by comparing the signature with those of known normal and abnormal transitions. The key advantage of the proposed strategy are its computational speed, inherent multivariate nature, and robustness to run-to-run variations, in addition to intuitiveness and visualization of the results. We illustrate the proposed method through two case studies: the Tennessee Eastman challenge problem and startup of a laboratory-scale distillation unit. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071022y
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7758-7771[article] Multivariate temporal data analysis using self-organizing maps. 2. Monitoring and diagnosis of multistate operations [texte imprimé] / Yew Seng Ng, Auteur ; Rajagopalan Srinivasan, Auteur . - 2008 . - P. 7758-7771.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7758-7771
Mots-clés : Self-organizing map (SOM) Multivariate temporal data analysis Résumé : The operation of transitions in continuous processes is challenging and often results in out-of-spec products, alarm floods, and abnormal situations. Therefore, efficient techniques for automated monitoring and fault diagnosis of such operations are essential. In Part 1 of this paper, we proposed a self-organizing map (SOM) training strategy for effectively visualizing multistate operations. In this part of the series, we use the same methodology as a representation scheme to compare operating trajectories and diagnosing faults during transient operations. In the proposed approach, clusters of SOM neurons, called neuronal clusters, serve as landmarks on the multivariate measurement space. Online data during the transition are reflected as a trajectory on the SOM and are converted to a sequence of neuronal clusters, which are the signature of the operating state. We have adapted the well-known Smith and Waterman discrete sequence comparison algorithm from bioinformatics to compare the state signatures and account for run-to-run variations. The proposed comparison method accounts explicitly for oscillations that are common in chemical processes. Online monitoring and diagnosis is performed by comparing the signature with those of known normal and abnormal transitions. The key advantage of the proposed strategy are its computational speed, inherent multivariate nature, and robustness to run-to-run variations, in addition to intuitiveness and visualization of the results. We illustrate the proposed method through two case studies: the Tennessee Eastman challenge problem and startup of a laboratory-scale distillation unit. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071022y Exemplaires
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Titre : PCA combined model-based design of experiments (DOE) criteria for differential and algebraic system parameter estimation Type de document : texte imprimé Auteurs : Yang Zhang, Auteur ; Thomas F. Edgar, Auteur Année de publication : 2008 Article en page(s) : P. 7772-7783 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Design of experiments (DOE) Résumé : Design of experiments (DOE) for parameter estimation in dynamic systems is receiving more attention from process system engineers. In this paper, a principal component analysis (PCA)-based optimal criterion (P-optimal) for model-based DOE is proposed that combines PCA with information matrix analysis. The P-optimal criterion is a general form that encompasses most widely used optimal design criteria such as D-, E-, and SV-optimal, and it can automatically choose the optimal objective function (criterion) to use for a specific differential and algebraic (DAE) system. Two engineering examples are used to validate the algorithms and assumptions. The advantages of P-optimal DOE include ease of reducing the scale of the optimization process by choosing parameter subsets to increase estimation accuracy of specific parameters and avoid an ill-conditioned information matrix. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071206c
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7772-7783[article] PCA combined model-based design of experiments (DOE) criteria for differential and algebraic system parameter estimation [texte imprimé] / Yang Zhang, Auteur ; Thomas F. Edgar, Auteur . - 2008 . - P. 7772-7783.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7772-7783
Mots-clés : Design of experiments (DOE) Résumé : Design of experiments (DOE) for parameter estimation in dynamic systems is receiving more attention from process system engineers. In this paper, a principal component analysis (PCA)-based optimal criterion (P-optimal) for model-based DOE is proposed that combines PCA with information matrix analysis. The P-optimal criterion is a general form that encompasses most widely used optimal design criteria such as D-, E-, and SV-optimal, and it can automatically choose the optimal objective function (criterion) to use for a specific differential and algebraic (DAE) system. Two engineering examples are used to validate the algorithms and assumptions. The advantages of P-optimal DOE include ease of reducing the scale of the optimization process by choosing parameter subsets to increase estimation accuracy of specific parameters and avoid an ill-conditioned information matrix. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071206c Exemplaires
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Titre : Simple dynamic gasifier model that runs in aspen dynamics Type de document : texte imprimé Auteurs : Patrick J. Robinson, Auteur ; William L. Luyben, Auteur Année de publication : 2008 Article en page(s) : P. 7784-7792 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Dynamic Gasifier chemical industries Résumé : Gasification has been used in industry on a relatively limited scale for many years, but it is emerging as the premier unit operation in the energy and chemical industries. The switch from expensive and insecure petroleum to solid hydrocarbon sources (coal and biomass) is occurring due to the vast amount of domestic solid resources, national security, and global warming issues. Gasification (or partial oxidation) is a vital component of “clean coal” technology. Sulfur and nitrogen emissions can be reduced, overall energy efficiency is increased, and carbon dioxide recovery and sequestration are facilitated. Gasification units in an electric power generation plant produce a fuel gas for driving combustion turbines. Gasification units in a chemical plant generate synthesis gas, which can be used to produce a wide spectrum of chemical products. Future plants are predicted to be hybrid power/chemical plants with gasification as the key unit operation. The widely used process simulator Aspen Plus provides a library of models that can be used to develop an overall gasifier model that handles solids, so steady-state design and optimization studies of processes with gasifiers can be undertaken. However, at the present time, these models cannot be exported into Aspen Dynamics because the automatic export of models involving solids from Aspen Plus to Aspen Dynamics is not supported. Dynamic simulations are essential for the development of stable and agile plantwide control structures for energy and chemical processes. This paper presents a simple approximate method for achieving the objective of having a gasifier model that can be exported into Aspen Dynamics. The basic idea is to use a high molecular weight hydrocarbon that is present in the Aspen library as a pseudofuel. This component should have the same 1:1 hydrogen-to-carbon ratio that is found in coal and biomass. For many plantwide dynamic studies, a rigorous high-fidelity dynamic model of the gasifier is not needed because its dynamics are very fast and the gasifier gas volume is a relatively small fraction of the total volume of the entire plant. The proposed approximate model captures the essential macroscale thermal, flow, composition, and pressure dynamics. This paper does not attempt to optimize the design or control of gasifiers but merely presents an idea of how to dynamically simulate coal gasification in an approximate way. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800227n
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7784-7792[article] Simple dynamic gasifier model that runs in aspen dynamics [texte imprimé] / Patrick J. Robinson, Auteur ; William L. Luyben, Auteur . - 2008 . - P. 7784-7792.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7784-7792
Mots-clés : Dynamic Gasifier chemical industries Résumé : Gasification has been used in industry on a relatively limited scale for many years, but it is emerging as the premier unit operation in the energy and chemical industries. The switch from expensive and insecure petroleum to solid hydrocarbon sources (coal and biomass) is occurring due to the vast amount of domestic solid resources, national security, and global warming issues. Gasification (or partial oxidation) is a vital component of “clean coal” technology. Sulfur and nitrogen emissions can be reduced, overall energy efficiency is increased, and carbon dioxide recovery and sequestration are facilitated. Gasification units in an electric power generation plant produce a fuel gas for driving combustion turbines. Gasification units in a chemical plant generate synthesis gas, which can be used to produce a wide spectrum of chemical products. Future plants are predicted to be hybrid power/chemical plants with gasification as the key unit operation. The widely used process simulator Aspen Plus provides a library of models that can be used to develop an overall gasifier model that handles solids, so steady-state design and optimization studies of processes with gasifiers can be undertaken. However, at the present time, these models cannot be exported into Aspen Dynamics because the automatic export of models involving solids from Aspen Plus to Aspen Dynamics is not supported. Dynamic simulations are essential for the development of stable and agile plantwide control structures for energy and chemical processes. This paper presents a simple approximate method for achieving the objective of having a gasifier model that can be exported into Aspen Dynamics. The basic idea is to use a high molecular weight hydrocarbon that is present in the Aspen library as a pseudofuel. This component should have the same 1:1 hydrogen-to-carbon ratio that is found in coal and biomass. For many plantwide dynamic studies, a rigorous high-fidelity dynamic model of the gasifier is not needed because its dynamics are very fast and the gasifier gas volume is a relatively small fraction of the total volume of the entire plant. The proposed approximate model captures the essential macroscale thermal, flow, composition, and pressure dynamics. This paper does not attempt to optimize the design or control of gasifiers but merely presents an idea of how to dynamically simulate coal gasification in an approximate way. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800227n Exemplaires
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Titre : Model for fast computation of blast furnace hearth erosion and buildup profiles Type de document : texte imprimé Auteurs : Johnny Brannbacka, Auteur ; Henrik Saxén, Auteur Année de publication : 2008 Article en page(s) : P. 7793-7801 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Blast furnace hearth Résumé : A model for estimation of the profiles of erosion and buildup material in the hearth of an ironmaking blast furnace has been developed. The model is based on thermocouple readings in the hearth wall and bottom and solves an inverse heat transfer problem for two-dimensional slices of the hearth geometry to estimate the inner profile. Special attention has been paid to the mathematical formulation of the problem at hand, yielding a general model optimized for fast computation. This includes a flexible formulation of the boundary conditions, a generic setup of the lining materials applied in the hearth refractory, and a sophisticated iterative procedure in the estimation of the location of the internal profile. These steps have led to a model that facilitates process analysis with estimation and reestimation of the furnace hearth conditions over whole campaigns using different parameter settings. The model has been applied to study the evolution of the hearth erosion and buildup formation processes in several industrial furnaces. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800384q
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7793-7801[article] Model for fast computation of blast furnace hearth erosion and buildup profiles [texte imprimé] / Johnny Brannbacka, Auteur ; Henrik Saxén, Auteur . - 2008 . - P. 7793-7801.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7793-7801
Mots-clés : Blast furnace hearth Résumé : A model for estimation of the profiles of erosion and buildup material in the hearth of an ironmaking blast furnace has been developed. The model is based on thermocouple readings in the hearth wall and bottom and solves an inverse heat transfer problem for two-dimensional slices of the hearth geometry to estimate the inner profile. Special attention has been paid to the mathematical formulation of the problem at hand, yielding a general model optimized for fast computation. This includes a flexible formulation of the boundary conditions, a generic setup of the lining materials applied in the hearth refractory, and a sophisticated iterative procedure in the estimation of the location of the internal profile. These steps have led to a model that facilitates process analysis with estimation and reestimation of the furnace hearth conditions over whole campaigns using different parameter settings. The model has been applied to study the evolution of the hearth erosion and buildup formation processes in several industrial furnaces. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800384q Exemplaires
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Titre : Mixed-integer Nonlinear programming models and algorithms for large-scale supply chain design with stochastic inventory management Type de document : texte imprimé Auteurs : Fengqi You, Auteur ; Ignacio E. Grossmann, Auteur Année de publication : 2008 Article en page(s) : P. 7802-7817 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Supply chain network Mixed-integer nonlinear programming (MINLP) Résumé : An important challenge for most chemical companies is to simultaneously consider inventory optimization and supply chain network design under demand uncertainty. This leads to a problem that requires integrating a stochastic inventory model with the supply chain network design model. This problem can be formulated as a large-scale combinatorial optimization model that includes nonlinear terms. Since these models are very difficult to solve, they require exploiting their properties and developing special solution techniques to reduce the computational effort. In this work, we analyze the properties of the basic model and develop solution techniques for a joint supply chain network design and inventory management model for a given product. The model is formulated as a nonlinear integer programming problem. By reformulating it as a mixed-integer nonlinear programming (MINLP) problem and using an associated convex relaxation model for initialization, we first propose a heuristic method to quickly obtain good-quality solutions. Further, a decomposition algorithm based on Lagrangean relaxation is developed for obtaining global or near-global optimal solutions. Extensive computational examples with up to 150 distribution centers and 150 retailers are presented to illustrate the performance of the algorithms and to compare them with the full-space solution. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800257x
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7802-7817[article] Mixed-integer Nonlinear programming models and algorithms for large-scale supply chain design with stochastic inventory management [texte imprimé] / Fengqi You, Auteur ; Ignacio E. Grossmann, Auteur . - 2008 . - P. 7802-7817.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7802-7817
Mots-clés : Supply chain network Mixed-integer nonlinear programming (MINLP) Résumé : An important challenge for most chemical companies is to simultaneously consider inventory optimization and supply chain network design under demand uncertainty. This leads to a problem that requires integrating a stochastic inventory model with the supply chain network design model. This problem can be formulated as a large-scale combinatorial optimization model that includes nonlinear terms. Since these models are very difficult to solve, they require exploiting their properties and developing special solution techniques to reduce the computational effort. In this work, we analyze the properties of the basic model and develop solution techniques for a joint supply chain network design and inventory management model for a given product. The model is formulated as a nonlinear integer programming problem. By reformulating it as a mixed-integer nonlinear programming (MINLP) problem and using an associated convex relaxation model for initialization, we first propose a heuristic method to quickly obtain good-quality solutions. Further, a decomposition algorithm based on Lagrangean relaxation is developed for obtaining global or near-global optimal solutions. Extensive computational examples with up to 150 distribution centers and 150 retailers are presented to illustrate the performance of the algorithms and to compare them with the full-space solution. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800257x Exemplaires
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Titre : Continuous-time formulation for the synthesis of water-using networks in batch plants Type de document : texte imprimé Auteurs : Cheng-Liang Chen, Auteur ; Chia-Yuan Chang, Auteur ; Jui-Yuan Lee, Auteur Année de publication : 2008 Article en page(s) : P. 7818-7832 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Water Mixed-integer nonlinear program (MINLP) Résumé : Water minimization is conducted by exploiting all possibilities of water reuse and recycle to reduce the freshwater consumption, as well as the wastewater generation. Because the starting and finishing times of batch water-using tasks are dependent on the production schedule as the inherent time dependence in batch processes, storage facilities are commonly equipped for the temporary storage of reusable water to partially bypass the time limitation. With a fixed production schedule, this paper presents a mathematical formulation for the synthesis of water-using networks in batch plants. Superstructures that incorporate all possible flow connections are built for modeling the batch water system. The proposed formulation is based on a continuous-time representation where different design objectives have been considered for an applicable network configuration. The design problems for the minimization of freshwater consumption, storage capacity, and the amount of connecting flows are formulated as nonlinear programs (NLPs), whereas the design problem for minimizing the number of connections will be a mixed-integer nonlinear program (MINLP). Representative examples from literature are provided to demonstrate the effectiveness of proposed formulation. Furthermore, the application of a fictitious contaminant is also developed, to address the forbidden match between assigned water-using tasks. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800573r
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7818-7832[article] Continuous-time formulation for the synthesis of water-using networks in batch plants [texte imprimé] / Cheng-Liang Chen, Auteur ; Chia-Yuan Chang, Auteur ; Jui-Yuan Lee, Auteur . - 2008 . - P. 7818-7832.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7818-7832
Mots-clés : Water Mixed-integer nonlinear program (MINLP) Résumé : Water minimization is conducted by exploiting all possibilities of water reuse and recycle to reduce the freshwater consumption, as well as the wastewater generation. Because the starting and finishing times of batch water-using tasks are dependent on the production schedule as the inherent time dependence in batch processes, storage facilities are commonly equipped for the temporary storage of reusable water to partially bypass the time limitation. With a fixed production schedule, this paper presents a mathematical formulation for the synthesis of water-using networks in batch plants. Superstructures that incorporate all possible flow connections are built for modeling the batch water system. The proposed formulation is based on a continuous-time representation where different design objectives have been considered for an applicable network configuration. The design problems for the minimization of freshwater consumption, storage capacity, and the amount of connecting flows are formulated as nonlinear programs (NLPs), whereas the design problem for minimizing the number of connections will be a mixed-integer nonlinear program (MINLP). Representative examples from literature are provided to demonstrate the effectiveness of proposed formulation. Furthermore, the application of a fictitious contaminant is also developed, to address the forbidden match between assigned water-using tasks. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800573r Exemplaires
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Titre : Removal of SO2 from industrial effluents by a novel twin fluid air-assist atomized spray scrubber Type de document : texte imprimé Auteurs : B. Rajmohan, Auteur ; S. N. Reddy, Auteur ; B. C. Meikap, Auteur Année de publication : 2008 Article en page(s) : P. 7833-7840 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : SO2 Gas Résumé : Wet scrubbers are employed in process industries for scrubbing both gases and particulates. To achieve a high efficiency for scrubbers and meet pollution control standards, industries need a new type of scrubber. In this paper an attempt has been made to design a new spray scrubber by a twin fluid air-assisted atomizer for the removal of SO2. Experimental results for scrubbing of lean sulfur dioxide gas by a novel spray tower using a twin fluid air-assisted atomizer have been presented. The efficiency of the spray column was found to increase with increase in spray liquid flow rate (8.35 × 10−6−33.34 × 10−6 m3/s) and concentration of SO2 gas (400−1200 ppm). A maximum of almost 99.99% efficiency was observed for 1200 ppm at 3.354 × 10−3 m3/s gas flow rate and 33.34 × 10−6 m3/s spray liquid flow rate. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800712a
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7833-7840[article] Removal of SO2 from industrial effluents by a novel twin fluid air-assist atomized spray scrubber [texte imprimé] / B. Rajmohan, Auteur ; S. N. Reddy, Auteur ; B. C. Meikap, Auteur . - 2008 . - P. 7833-7840.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7833-7840
Mots-clés : SO2 Gas Résumé : Wet scrubbers are employed in process industries for scrubbing both gases and particulates. To achieve a high efficiency for scrubbers and meet pollution control standards, industries need a new type of scrubber. In this paper an attempt has been made to design a new spray scrubber by a twin fluid air-assisted atomizer for the removal of SO2. Experimental results for scrubbing of lean sulfur dioxide gas by a novel spray tower using a twin fluid air-assisted atomizer have been presented. The efficiency of the spray column was found to increase with increase in spray liquid flow rate (8.35 × 10−6−33.34 × 10−6 m3/s) and concentration of SO2 gas (400−1200 ppm). A maximum of almost 99.99% efficiency was observed for 1200 ppm at 3.354 × 10−3 m3/s gas flow rate and 33.34 × 10−6 m3/s spray liquid flow rate. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800712a Exemplaires
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Titre : Development of a CaO-based CO2 sorbent with improved cyclic stability Type de document : texte imprimé Auteurs : Karl O. Albrecht, Auteur ; Kyle S. Wagenbach, Auteur ; Justinus A. Satrio, Auteur Année de publication : 2008 Article en page(s) : P. 7841-7848 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : CaO-based CO2 Résumé : The carbonation of CaO is an attractive method for removing CO2 from hot gas mixtures. However, regeneration and reuse of a CaO-based sorbent causes a gradual decline in absorption capacity, which ultimately limits the life of the material. Various methods have been proposed for increasing the life cycle performance of a CaO-based sorbent. Two of these methods were selected for further investigation. One method incorporates an “inert” material in the sorbent, while a second method stabilizes the sorbent through controlled sintering. Promising results were achieved with both methods when they were applied separately to a sorbent derived from a natural limestone. In one case MgO was finely dispersed within the sorbent, where it served as an “inert” material in the sense that it did not absorb CO2. A concentration of approximately 20 wt % appeared to be nearly optimal. In a second case the sorbent was stabilized by calcining the material at 1100 °C for 5 h. Although neither method produced a completely stable material, the stability of the sorbents was improved sufficiently so that by the end of a 1200-cycle test the absorption capacity of either of the treated sorbents was 45% greater than that of an untreated sorbent and the rate of decline was very small. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8007743
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7841-7848[article] Development of a CaO-based CO2 sorbent with improved cyclic stability [texte imprimé] / Karl O. Albrecht, Auteur ; Kyle S. Wagenbach, Auteur ; Justinus A. Satrio, Auteur . - 2008 . - P. 7841-7848.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7841-7848
Mots-clés : CaO-based CO2 Résumé : The carbonation of CaO is an attractive method for removing CO2 from hot gas mixtures. However, regeneration and reuse of a CaO-based sorbent causes a gradual decline in absorption capacity, which ultimately limits the life of the material. Various methods have been proposed for increasing the life cycle performance of a CaO-based sorbent. Two of these methods were selected for further investigation. One method incorporates an “inert” material in the sorbent, while a second method stabilizes the sorbent through controlled sintering. Promising results were achieved with both methods when they were applied separately to a sorbent derived from a natural limestone. In one case MgO was finely dispersed within the sorbent, where it served as an “inert” material in the sense that it did not absorb CO2. A concentration of approximately 20 wt % appeared to be nearly optimal. In a second case the sorbent was stabilized by calcining the material at 1100 °C for 5 h. Although neither method produced a completely stable material, the stability of the sorbents was improved sufficiently so that by the end of a 1200-cycle test the absorption capacity of either of the treated sorbents was 45% greater than that of an untreated sorbent and the rate of decline was very small. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8007743 Exemplaires
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Titre : An ion-imprinted monolith for in vitro removal of iron out of human plasma with beta thalassemia Type de document : texte imprimé Auteurs : Serpil Ozkara, Auteur ; Ridvan Say, Auteur ; Cenk Andaç, Auteur ; Adil Denozli, Auteur Année de publication : 2008 Article en page(s) : P. 78497856 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ion-imprinted Résumé : The aim of this study is to prepare an ion-imprinted monolith which can be utilized to remove Fe3+ from beta thalassemia patient plasma. Fe3+, as a template, was initially complexed with N-methacryloyl-(l)-cysteine methyl ester (MAC) to form MAC−Fe3+ (the complex monomer), which was then polymerized with hydroxyethyl methacrylate (HEMA) to constitude a Fe3+-imprinted poly(HEMA−MAC) monolith (PHEMAC−Fe3+) by bulk polymerization method. The template (Fe3+) was removed from the polymer by 0.1 M EDTA solution. The specific surface area of PHEMAC−Fe3+ was found to be 35.2 m2/g with a swelling ratio of 60.2%. A maximum adsorption capacity of 150 μg Fe3+/g was observed with PHEMAC−Fe3+. It was determined that PHEMAC−Fe3+ possesses relative selectivity coefficients for Fe3+/Cd2+ and Fe3+/Ni2+, which are 42.6 and 36.1, respectively, times greater than nonimprinted monolith (produced in the absence of Fe3+, PHEMAC). The PHEMAC−Fe3+ monolith has been recovered and reused many times without a significant decrease in its adsorption capacity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071471y
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 78497856[article] An ion-imprinted monolith for in vitro removal of iron out of human plasma with beta thalassemia [texte imprimé] / Serpil Ozkara, Auteur ; Ridvan Say, Auteur ; Cenk Andaç, Auteur ; Adil Denozli, Auteur . - 2008 . - P. 78497856.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 78497856
Mots-clés : Ion-imprinted Résumé : The aim of this study is to prepare an ion-imprinted monolith which can be utilized to remove Fe3+ from beta thalassemia patient plasma. Fe3+, as a template, was initially complexed with N-methacryloyl-(l)-cysteine methyl ester (MAC) to form MAC−Fe3+ (the complex monomer), which was then polymerized with hydroxyethyl methacrylate (HEMA) to constitude a Fe3+-imprinted poly(HEMA−MAC) monolith (PHEMAC−Fe3+) by bulk polymerization method. The template (Fe3+) was removed from the polymer by 0.1 M EDTA solution. The specific surface area of PHEMAC−Fe3+ was found to be 35.2 m2/g with a swelling ratio of 60.2%. A maximum adsorption capacity of 150 μg Fe3+/g was observed with PHEMAC−Fe3+. It was determined that PHEMAC−Fe3+ possesses relative selectivity coefficients for Fe3+/Cd2+ and Fe3+/Ni2+, which are 42.6 and 36.1, respectively, times greater than nonimprinted monolith (produced in the absence of Fe3+, PHEMAC). The PHEMAC−Fe3+ monolith has been recovered and reused many times without a significant decrease in its adsorption capacity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071471y Exemplaires
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Titre : Preparation and characterization of a selective nitric oxide adsorbent based on cobalt(II) phthalocyanine tetrasulfonic acid Type de document : texte imprimé Auteurs : W. J. Desisto, Auteur ; R. Cashon, Auteur ; D. Cassidy, Auteur ; N. Hill, Auteur Année de publication : 2008 Article en page(s) : P. 7857-7861 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Nitric oxide (NO) cobalt(II) phthalocyanine tetrasulfonic acid (CoPcS Résumé : We report the synthesis and characterization of a selective nitric oxide (NO) adsorbent based on the covalent binding of cobalt(II) phthalocyanine tetrasulfonic acid (CoPcS) onto imidazole-functionalized mesoporous silica gel beads. The equilibrium data indicated that the adsorption of NO was highly favorable, approaching irreversible adsorption. The breakthrough curves for NO were modeled assuming irreversible adsorption and resulted in pore diffusivities through the packed bed of 0.1−0.3 cm2·s−1. Adsorption experiments of NO in the presence of nitrogen, water vapor, and ammonia indicated that the adsorption was selective for NO. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8000293
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7857-7861[article] Preparation and characterization of a selective nitric oxide adsorbent based on cobalt(II) phthalocyanine tetrasulfonic acid [texte imprimé] / W. J. Desisto, Auteur ; R. Cashon, Auteur ; D. Cassidy, Auteur ; N. Hill, Auteur . - 2008 . - P. 7857-7861.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7857-7861
Mots-clés : Nitric oxide (NO) cobalt(II) phthalocyanine tetrasulfonic acid (CoPcS Résumé : We report the synthesis and characterization of a selective nitric oxide (NO) adsorbent based on the covalent binding of cobalt(II) phthalocyanine tetrasulfonic acid (CoPcS) onto imidazole-functionalized mesoporous silica gel beads. The equilibrium data indicated that the adsorption of NO was highly favorable, approaching irreversible adsorption. The breakthrough curves for NO were modeled assuming irreversible adsorption and resulted in pore diffusivities through the packed bed of 0.1−0.3 cm2·s−1. Adsorption experiments of NO in the presence of nitrogen, water vapor, and ammonia indicated that the adsorption was selective for NO. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8000293 Exemplaires
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Titre : Component distribution between light and heavy phases in biodiesel processes Type de document : texte imprimé Auteurs : Renzo Felice, Auteur ; Danilo de Faveri, Auteur ; Paola De Andreis, Auteur ; Piero Ottonello, Auteur Année de publication : 2008 Article en page(s) : P. 7862-7867 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Biodiesel Résumé : Knowledge of the component distribution in the biodiesel production process is fundamental both during the transesterification reaction, where reactants are partially miscible, and during the recovery of the final products, which exist in two separate phases, a heavy one containing nearly all of the glycerol and a light one containing nearly all of the biodiesel. In this article, a simple methodology able to predict the product distribution at equilibrium between the heavy and light phases is suggested. Experimental equilibrium data for mixtures of two (biodiesel and glycerol), three (biodiesel, glycerol, and methanol), and four (biodiesel, glycerol, methanol, and water) components are collected and correlated with the Wilson activity coefficient model. The approach is based on thermodynamic data already available in the literature, without the addition of any empirical fitting parameter. A small effect brought about by the presence of water at low concentrations on methanol distribution between the two phases is pointed out and qualitatively supported by the model predictions. The influence of the addition of electrolyte contaminants (soap or catalysts) is also considered. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800510w
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7862-7867[article] Component distribution between light and heavy phases in biodiesel processes [texte imprimé] / Renzo Felice, Auteur ; Danilo de Faveri, Auteur ; Paola De Andreis, Auteur ; Piero Ottonello, Auteur . - 2008 . - P. 7862-7867.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7862-7867
Mots-clés : Biodiesel Résumé : Knowledge of the component distribution in the biodiesel production process is fundamental both during the transesterification reaction, where reactants are partially miscible, and during the recovery of the final products, which exist in two separate phases, a heavy one containing nearly all of the glycerol and a light one containing nearly all of the biodiesel. In this article, a simple methodology able to predict the product distribution at equilibrium between the heavy and light phases is suggested. Experimental equilibrium data for mixtures of two (biodiesel and glycerol), three (biodiesel, glycerol, and methanol), and four (biodiesel, glycerol, methanol, and water) components are collected and correlated with the Wilson activity coefficient model. The approach is based on thermodynamic data already available in the literature, without the addition of any empirical fitting parameter. A small effect brought about by the presence of water at low concentrations on methanol distribution between the two phases is pointed out and qualitatively supported by the model predictions. The influence of the addition of electrolyte contaminants (soap or catalysts) is also considered. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800510w Exemplaires
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Titre : Natural organic matter adsorption onto granular activated carbons : implications in the molecular weight and disinfection byproducts formation Type de document : texte imprimé Auteurs : Unai Iriarte-Velasco, Auteur ; Jon I. Álvarez-Uriarte, Auteur ; Noemí Chimeno-Alanís, Auteur ; Juan R. Gonzalez-Velasco, Auteur Année de publication : 2008 Article en page(s) : P. 7868-7876 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Carbon Granular activated carbon (GAC) Thermogravimetric analysis (TGA) Résumé : Adsorption of natural organic matter (NOM) by granular activated carbon (GAC) was studied. Three different carbons of different origin were initially used. The physical properties were studied by means of N2 adsorption. Chemical properties were studied by means of thermogravimetric analysis (TGA), acid−base titrations, and FTIR. Only one of the carbons showed a broad adsorption band in the 1300−1000 cm−1 region in FTIR spectra, which can be assigned to C−O stretching and O−H bending modes of alcoholic, phenolic, and carboxylic groups. Adsorption of NOM was studied by batch adsorption experiments. Uptake of NOM by the different carbons was evaluated by UV absorbance, disinfection byproduct formation potential tests, and HPLC-SEC chromatography. Freundlich equation was used to fit equilibrium data. pHPZC and overall surface basicity were shown to improve the removal of THM precursors. Differences in the molecular weight distribution of the adsorbed material by different carbons were reported. A clear correlation was found between the reduction in the THM formation capacity of sample and the reduction in intensity of a specific peak in SEC chromatograms. Furthermore, THMFP tests showed the existence of some fractions of NOM not adsorbable with activated carbons and undetected by measurement of DOC. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800912y
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7868-7876[article] Natural organic matter adsorption onto granular activated carbons : implications in the molecular weight and disinfection byproducts formation [texte imprimé] / Unai Iriarte-Velasco, Auteur ; Jon I. Álvarez-Uriarte, Auteur ; Noemí Chimeno-Alanís, Auteur ; Juan R. Gonzalez-Velasco, Auteur . - 2008 . - P. 7868-7876.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7868-7876
Mots-clés : Carbon Granular activated carbon (GAC) Thermogravimetric analysis (TGA) Résumé : Adsorption of natural organic matter (NOM) by granular activated carbon (GAC) was studied. Three different carbons of different origin were initially used. The physical properties were studied by means of N2 adsorption. Chemical properties were studied by means of thermogravimetric analysis (TGA), acid−base titrations, and FTIR. Only one of the carbons showed a broad adsorption band in the 1300−1000 cm−1 region in FTIR spectra, which can be assigned to C−O stretching and O−H bending modes of alcoholic, phenolic, and carboxylic groups. Adsorption of NOM was studied by batch adsorption experiments. Uptake of NOM by the different carbons was evaluated by UV absorbance, disinfection byproduct formation potential tests, and HPLC-SEC chromatography. Freundlich equation was used to fit equilibrium data. pHPZC and overall surface basicity were shown to improve the removal of THM precursors. Differences in the molecular weight distribution of the adsorbed material by different carbons were reported. A clear correlation was found between the reduction in the THM formation capacity of sample and the reduction in intensity of a specific peak in SEC chromatograms. Furthermore, THMFP tests showed the existence of some fractions of NOM not adsorbable with activated carbons and undetected by measurement of DOC. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800912y Exemplaires
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Titre : An improved local composition expression and its implication for phase equilibrium models Type de document : texte imprimé Auteurs : Ivan L. Shulgin, Auteur ; Eli Ruckenstein, Auteur Année de publication : 2008 Article en page(s) : P. 7877-7880 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Local composition (LC) equilibrium models Résumé : A modified local composition (LC) expression is suggested, which accounts for the recent finding that the LC in an ideal binary mixture should be equal to the bulk composition only when the molar volumes of the two pure components are equal. However, the expressions available in the literature for the LCs in binary mixtures do not satisfy this requirement. Some LCs are examined including the popular LC-based NRTL model, to show how the above inconsistency can be eliminated. Further, the emphasis is on the modified NRTL model. The newly derived activity coefficient expressions have three adjustable parameters as the NRTL equations do, but contain, in addition, the ratio of the molar volumes of the pure components, a quantity that is usually available. The correlation capability of the modified activity coefficients was compared to the traditional NRTL equations for 42 vapor−liquid equilibrium data sets from two different kinds of binary mixtures: (i) highly nonideal alcohol/water mixtures (33 sets), and (ii) mixtures formed of weakly interacting components, such as benzene, hexafluorobenzene, toluene, and cyclohexane (9 sets). The new equations provided better performances in correlating the vapor pressure than the NRTL for 36 data sets, less well for 4 data sets, and equal performances for 2 data sets. Similar modifications can be applied to any phase equilibrium model based on the LC concept. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800897j
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7877-7880[article] An improved local composition expression and its implication for phase equilibrium models [texte imprimé] / Ivan L. Shulgin, Auteur ; Eli Ruckenstein, Auteur . - 2008 . - P. 7877-7880.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7877-7880
Mots-clés : Local composition (LC) equilibrium models Résumé : A modified local composition (LC) expression is suggested, which accounts for the recent finding that the LC in an ideal binary mixture should be equal to the bulk composition only when the molar volumes of the two pure components are equal. However, the expressions available in the literature for the LCs in binary mixtures do not satisfy this requirement. Some LCs are examined including the popular LC-based NRTL model, to show how the above inconsistency can be eliminated. Further, the emphasis is on the modified NRTL model. The newly derived activity coefficient expressions have three adjustable parameters as the NRTL equations do, but contain, in addition, the ratio of the molar volumes of the pure components, a quantity that is usually available. The correlation capability of the modified activity coefficients was compared to the traditional NRTL equations for 42 vapor−liquid equilibrium data sets from two different kinds of binary mixtures: (i) highly nonideal alcohol/water mixtures (33 sets), and (ii) mixtures formed of weakly interacting components, such as benzene, hexafluorobenzene, toluene, and cyclohexane (9 sets). The new equations provided better performances in correlating the vapor pressure than the NRTL for 36 data sets, less well for 4 data sets, and equal performances for 2 data sets. Similar modifications can be applied to any phase equilibrium model based on the LC concept. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800897j Exemplaires
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Titre : Enhancing CO-water mass transfer by functionalized MCM41 nanoparticles Type de document : texte imprimé Auteurs : Haiyang Zhu, Auteur ; Brent H. Shanks, Auteur ; Heindel, Theodore J., Auteur Année de publication : 2008 Article en page(s) : P. 7881-7887 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : CO-Water Gas Résumé : Organic groups are grafted to ∼250-nm-diameter MCM41 nanoparticles with a spherical morphology to enhance the CO−water volumetric mass-transfer coefficient (kLa) for synthesis gas fermentation. The results indicate that (i) ∼250-nm MCM41 nanoparticles show a higher kLa value than large silica particles (1.4 and 7 μm), (ii) surface hydroxyl groups on MCM41 nanoparticles play an important role in mass-transfer enhancement, (iii) organic groups grafted to MCM41 modify the mass-transfer enhancement, and (iv) mercaptan groups grafted to MCM41 show the most mass-transfer enhancement of ∼1.9 times that of no nanoparticle addition. The CO−water mass-transfer enhancement depends on the interaction between the nanoparticles and the CO molecules, which is influenced by the hydrophobicity of the nanoparticles and the functional group on the nanoparticles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800238w
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7881-7887[article] Enhancing CO-water mass transfer by functionalized MCM41 nanoparticles [texte imprimé] / Haiyang Zhu, Auteur ; Brent H. Shanks, Auteur ; Heindel, Theodore J., Auteur . - 2008 . - P. 7881-7887.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7881-7887
Mots-clés : CO-Water Gas Résumé : Organic groups are grafted to ∼250-nm-diameter MCM41 nanoparticles with a spherical morphology to enhance the CO−water volumetric mass-transfer coefficient (kLa) for synthesis gas fermentation. The results indicate that (i) ∼250-nm MCM41 nanoparticles show a higher kLa value than large silica particles (1.4 and 7 μm), (ii) surface hydroxyl groups on MCM41 nanoparticles play an important role in mass-transfer enhancement, (iii) organic groups grafted to MCM41 modify the mass-transfer enhancement, and (iv) mercaptan groups grafted to MCM41 show the most mass-transfer enhancement of ∼1.9 times that of no nanoparticle addition. The CO−water mass-transfer enhancement depends on the interaction between the nanoparticles and the CO molecules, which is influenced by the hydrophobicity of the nanoparticles and the functional group on the nanoparticles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800238w Exemplaires
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Titre : Simulation of moisture uptake and transport in a bed of urea particles Type de document : texte imprimé Auteurs : Xiao-Dong Nie, Auteur ; Richard W. Evitts, Auteur ; Robert W. Besant, Auteur Année de publication : 2008 Article en page(s) : P. 7888-7896 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Granular urea Moisture Résumé : Granular urea is a commonly used fertilizer, and it is subject to caking when exposed to small quantities of moisture. In this paper, coupled heat and moisture transport equations are used to predict one-dimensional temperature and moisture content distributions in a bed of bulk granular urea particles when humid air flows uniformly through the bed. The moisture sorption and transport processes consider two computational domains—water vapor diffusion inside each particle and water vapor convection and diffusion in the interstitial air space in the urea particle bed. For energy transport, the temperature is assumed to be uniform inside each particle, but convective heat transfer and conduction between the urea particles and the interstitial air outside particles occur throughout the bed. Comparisons between simulations and data show agreement within the experimental uncertainties for low Reynolds number conditions, where both internal particle and external bed sorption processes are important for porous urea particles in bulk storage. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701744g
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7888-7896[article] Simulation of moisture uptake and transport in a bed of urea particles [texte imprimé] / Xiao-Dong Nie, Auteur ; Richard W. Evitts, Auteur ; Robert W. Besant, Auteur . - 2008 . - P. 7888-7896.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7888-7896
Mots-clés : Granular urea Moisture Résumé : Granular urea is a commonly used fertilizer, and it is subject to caking when exposed to small quantities of moisture. In this paper, coupled heat and moisture transport equations are used to predict one-dimensional temperature and moisture content distributions in a bed of bulk granular urea particles when humid air flows uniformly through the bed. The moisture sorption and transport processes consider two computational domains—water vapor diffusion inside each particle and water vapor convection and diffusion in the interstitial air space in the urea particle bed. For energy transport, the temperature is assumed to be uniform inside each particle, but convective heat transfer and conduction between the urea particles and the interstitial air outside particles occur throughout the bed. Comparisons between simulations and data show agreement within the experimental uncertainties for low Reynolds number conditions, where both internal particle and external bed sorption processes are important for porous urea particles in bulk storage. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701744g Exemplaires
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Titre : Characterization of blast furnace slag-Ca(OH)2 sorbents for flue gas desulfurization Type de document : texte imprimé Auteurs : Guozhuo Gong, Auteur ; Shufeng Ye, Auteur ; Yajun Tian, Auteur ; Yanbin Cui, Auteur Année de publication : 2008 Article en page(s) : P. 7897-7902 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Furnace Slag Flue Gas Desulfurization Résumé : A series of sorbents for flue gas SO2 scrubbing have been prepared from hydrated lime (HL) and blast furnace slag (BFS) with the factorial experiment design method. The sorbents were characterized and tested for SO2 reactivity in a differential fixed-bed reactor. It was found that, due to the formation of calcium silicate hydrates (CSHs), the reactivities of the sorbents prepared were higher than that of Ca(OH)2 alone. The present sorbent gave better utilization of the Ca originated from the Ca(OH)2 precursor and provided additional utilization capacity of the Ca derived from BFS. The present sorbents were mesoporous, and their specific surface areas were linearly correlated with their mesopore volumes. When the weight ratio of BFS/HL varied between 1/9 and 3/7, the SO2 capture of the sorbents prepared was independent of specific surface area. When the weight ratio of BFS/HL varied between 7/3 and 9/1, the SO2 capture was seen to increase linearly with specific surface area. Among the four process variables studied for the sorbent prepared in this work, the weight ratio of BFS/HL was found to be the most significant for the specific surface area of the sorbents. The optimum BSF/HL ratio looked to be around 9/1. The second and the third process variables studied were hydration time and the ratio of water/solid, respectively. The optimum hydration time was about 10 h, while the optimum water/solid ratio was 25/1. The last process variable studied was slurrying temperature. Slurrying temperature (T) had little effect on the specific surface area of the BFS/HL sorbent in the range 50−80 °C. This is useful for preparing high-performance silica-enhanced desulfurization sorbents for dry and semidry flue gas desulfurization processes, taking advantage of the waste BFS. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800873b
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7897-7902[article] Characterization of blast furnace slag-Ca(OH)2 sorbents for flue gas desulfurization [texte imprimé] / Guozhuo Gong, Auteur ; Shufeng Ye, Auteur ; Yajun Tian, Auteur ; Yanbin Cui, Auteur . - 2008 . - P. 7897-7902.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7897-7902
Mots-clés : Furnace Slag Flue Gas Desulfurization Résumé : A series of sorbents for flue gas SO2 scrubbing have been prepared from hydrated lime (HL) and blast furnace slag (BFS) with the factorial experiment design method. The sorbents were characterized and tested for SO2 reactivity in a differential fixed-bed reactor. It was found that, due to the formation of calcium silicate hydrates (CSHs), the reactivities of the sorbents prepared were higher than that of Ca(OH)2 alone. The present sorbent gave better utilization of the Ca originated from the Ca(OH)2 precursor and provided additional utilization capacity of the Ca derived from BFS. The present sorbents were mesoporous, and their specific surface areas were linearly correlated with their mesopore volumes. When the weight ratio of BFS/HL varied between 1/9 and 3/7, the SO2 capture of the sorbents prepared was independent of specific surface area. When the weight ratio of BFS/HL varied between 7/3 and 9/1, the SO2 capture was seen to increase linearly with specific surface area. Among the four process variables studied for the sorbent prepared in this work, the weight ratio of BFS/HL was found to be the most significant for the specific surface area of the sorbents. The optimum BSF/HL ratio looked to be around 9/1. The second and the third process variables studied were hydration time and the ratio of water/solid, respectively. The optimum hydration time was about 10 h, while the optimum water/solid ratio was 25/1. The last process variable studied was slurrying temperature. Slurrying temperature (T) had little effect on the specific surface area of the BFS/HL sorbent in the range 50−80 °C. This is useful for preparing high-performance silica-enhanced desulfurization sorbents for dry and semidry flue gas desulfurization processes, taking advantage of the waste BFS. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800873b Exemplaires
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Titre : Comparison of corresponding-states-based correlations for the prediction of the vaporization enthalpy of fluids Type de document : texte imprimé Auteurs : Angel Mulero, Auteur ; Isidro Cachadina, Auteur ; M. I. Parra, Auteur Année de publication : 2008 Article en page(s) : P. 7903-7916 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Analytical correlations vaporization of fluids DIPPR project Résumé : Four analytical correlations, including one proposed very recently, were used to calculate the enthalpy of vaporization of fluids. These correlations are based on the Pitzer et al. corresponding states principle and require as input the critical temperature and the acentric factor. They have generally been applied only to a reduced number of normal fluids (nonpolar, slightly polar, non-hydrogen-bonding, and nonquantum fluids), but in this paper we check their accuracy and applicability for 1594 polar and nonpolar fluids grouped into 81 families. The results are compared with the values accepted by the DIPPR project. Recommendations are given for the use of each model and for the choice of the adequate model for each family of fluids. In particular, we found that the most recent model, proposed by Morgan, gives the best results for most of the families and behaves better than the other models at both high and low temperatures. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800557q
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7903-7916[article] Comparison of corresponding-states-based correlations for the prediction of the vaporization enthalpy of fluids [texte imprimé] / Angel Mulero, Auteur ; Isidro Cachadina, Auteur ; M. I. Parra, Auteur . - 2008 . - P. 7903-7916.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7903-7916
Mots-clés : Analytical correlations vaporization of fluids DIPPR project Résumé : Four analytical correlations, including one proposed very recently, were used to calculate the enthalpy of vaporization of fluids. These correlations are based on the Pitzer et al. corresponding states principle and require as input the critical temperature and the acentric factor. They have generally been applied only to a reduced number of normal fluids (nonpolar, slightly polar, non-hydrogen-bonding, and nonquantum fluids), but in this paper we check their accuracy and applicability for 1594 polar and nonpolar fluids grouped into 81 families. The results are compared with the values accepted by the DIPPR project. Recommendations are given for the use of each model and for the choice of the adequate model for each family of fluids. In particular, we found that the most recent model, proposed by Morgan, gives the best results for most of the families and behaves better than the other models at both high and low temperatures. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800557q Exemplaires
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Titre : Online NMR spectroscopic study of species distribution in MDEA-H2O-CO2 and MDEA-PIP-H2O-CO2 Type de document : texte imprimé Auteurs : Wolfram Bottinger, Auteur ; Michael Maiwald, Auteur ; Hans Hasse, Auteur Année de publication : 2008 Article en page(s) : P. 7917-7926 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Nuclear magnetic resonance(NMR) Carbon dioxide (CO2) Vapor-liquid equilibrium (VLE) Résumé : Quantitative online nuclear magnetic resonance (NMR) spectroscopy was used to study the species distribution in solutions of carbon dioxide (CO2) in aqueous N-methyldiethanolamine (MDEA), and MDEA + piperazine (PIP). The mass fraction of MDEA in the unloaded ternary solution was 0.2, 0.3, and 0.4 g/g. In quaternary solutions, the mass fraction of MDEA was 0.3 g/g, and that of PIP was 0.1 g/g. The temperature ranged from 293 K to 333 K, and the overall CO2 loading was up to 1.4 molCO2/molamine. For the measurements, a special apparatus was used that allowed the mixtures to be prepared gravimetrically and applied pressures up to 25 bar to keep the CO2 in solution. It was coupled to a 400 MHz NMR spectrometer by heated capillaries. Using both 1H and 13C NMR spectroscopy, quantitative information on the concentrations of the following species was obtained: amines, carbamates, bicarbonate, and CO2. Because of the fast proton transfer between molecular and protonated amines, only the sum of their concentrations can be determined. Furthermore, a byproduct was observed and quantified. The experimental data were used to develop a thermodynamic model of the studied electrolyte solutions, based on the extended Pitzer GE-model. In the model development, vapor−liquid equilibrium (VLE) data from the literature also were included. The model describes both the species distribution and the VLE of the studied mixtures. The properties of the quaternary system are predicted from information on the subsystems. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800914m
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7917-7926[article] Online NMR spectroscopic study of species distribution in MDEA-H2O-CO2 and MDEA-PIP-H2O-CO2 [texte imprimé] / Wolfram Bottinger, Auteur ; Michael Maiwald, Auteur ; Hans Hasse, Auteur . - 2008 . - P. 7917-7926.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7917-7926
Mots-clés : Nuclear magnetic resonance(NMR) Carbon dioxide (CO2) Vapor-liquid equilibrium (VLE) Résumé : Quantitative online nuclear magnetic resonance (NMR) spectroscopy was used to study the species distribution in solutions of carbon dioxide (CO2) in aqueous N-methyldiethanolamine (MDEA), and MDEA + piperazine (PIP). The mass fraction of MDEA in the unloaded ternary solution was 0.2, 0.3, and 0.4 g/g. In quaternary solutions, the mass fraction of MDEA was 0.3 g/g, and that of PIP was 0.1 g/g. The temperature ranged from 293 K to 333 K, and the overall CO2 loading was up to 1.4 molCO2/molamine. For the measurements, a special apparatus was used that allowed the mixtures to be prepared gravimetrically and applied pressures up to 25 bar to keep the CO2 in solution. It was coupled to a 400 MHz NMR spectrometer by heated capillaries. Using both 1H and 13C NMR spectroscopy, quantitative information on the concentrations of the following species was obtained: amines, carbamates, bicarbonate, and CO2. Because of the fast proton transfer between molecular and protonated amines, only the sum of their concentrations can be determined. Furthermore, a byproduct was observed and quantified. The experimental data were used to develop a thermodynamic model of the studied electrolyte solutions, based on the extended Pitzer GE-model. In the model development, vapor−liquid equilibrium (VLE) data from the literature also were included. The model describes both the species distribution and the VLE of the studied mixtures. The properties of the quaternary system are predicted from information on the subsystems. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800914m Exemplaires
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Titre : Vapor-liquid-liquid equilibria for aqueous systems with methyl acetate, methyl propionate, and methanol Type de document : texte imprimé Auteurs : Cheng-Ting Hsieh, Auteur ; Ming-Jer Lee, Auteur ; Ho-mu Lin, Auteur Année de publication : 2008 Article en page(s) : P. 7927-7933 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Vapor− liquid− liquid equilibrium (VLLE) Aqueous Systems Résumé : Vapor−liquid−liquid equilibrium (VLLE) properties were measured with a static apparatus for mixtures of water + methyl acetate, water + methyl propionate, water + methyl acetate + methanol, and water + methyl propionate + methanol at temperatures ranging from 313.24 to 348.15 K. Both ternary systems exhibit type I liquid−liquid equilibrium (LLE) behavior. By checking with the Othmer−Tobias equation, the experimental tie-line data of these two ternary systems appeared to be consistent. The binary VLLE data were correlated satisfactorily with the UNIQUAC model for water + methyl acetate and water + methyl propionate. While the UNIQUAC model with the parameters determined from the phase equilibrium data of the constituent binaries overestimated the two-liquid-phase regions of the ternary systems, the representation of the binodal loci was substantially improved as the six parameters of the UNIQUAC model were determined simultaneously from the ternary VLLE data. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800840r
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7927-7933[article] Vapor-liquid-liquid equilibria for aqueous systems with methyl acetate, methyl propionate, and methanol [texte imprimé] / Cheng-Ting Hsieh, Auteur ; Ming-Jer Lee, Auteur ; Ho-mu Lin, Auteur . - 2008 . - P. 7927-7933.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7927-7933
Mots-clés : Vapor− liquid− liquid equilibrium (VLLE) Aqueous Systems Résumé : Vapor−liquid−liquid equilibrium (VLLE) properties were measured with a static apparatus for mixtures of water + methyl acetate, water + methyl propionate, water + methyl acetate + methanol, and water + methyl propionate + methanol at temperatures ranging from 313.24 to 348.15 K. Both ternary systems exhibit type I liquid−liquid equilibrium (LLE) behavior. By checking with the Othmer−Tobias equation, the experimental tie-line data of these two ternary systems appeared to be consistent. The binary VLLE data were correlated satisfactorily with the UNIQUAC model for water + methyl acetate and water + methyl propionate. While the UNIQUAC model with the parameters determined from the phase equilibrium data of the constituent binaries overestimated the two-liquid-phase regions of the ternary systems, the representation of the binodal loci was substantially improved as the six parameters of the UNIQUAC model were determined simultaneously from the ternary VLLE data. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800840r Exemplaires
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Titre : Flow patterns: does gas/solids flow pattern correspond to churn flow in gas/liquid flow Type de document : texte imprimé Auteurs : B. J. Azzopardi, Auteur Année de publication : 2008 Article en page(s) : P. 7934-7939 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Gas/solids flow Electrical capacitance tomography Probability density functions velocity Résumé : The output of electrical capacitance tomography measurements of gas/solids flow in a vertical pipe have been analyzed to extract flow pattern information. Two approaches already used for gas/liquid flows were employed. One uses the shape of the probability density functions of the cross-sectionally averaged gas fraction time series. The other considered the velocities of periodic structures, i.e., pulses of particles. The results from both techniques showed that a flow pattern similar to churn flow in gas/liquid flow was indicated. When the gas/solids flow rates are plotted on a gas/liquid flow pattern map, they fell in the churn flow region. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800868b
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7934-7939[article] Flow patterns: does gas/solids flow pattern correspond to churn flow in gas/liquid flow [texte imprimé] / B. J. Azzopardi, Auteur . - 2008 . - P. 7934-7939.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7934-7939
Mots-clés : Gas/solids flow Electrical capacitance tomography Probability density functions velocity Résumé : The output of electrical capacitance tomography measurements of gas/solids flow in a vertical pipe have been analyzed to extract flow pattern information. Two approaches already used for gas/liquid flows were employed. One uses the shape of the probability density functions of the cross-sectionally averaged gas fraction time series. The other considered the velocities of periodic structures, i.e., pulses of particles. The results from both techniques showed that a flow pattern similar to churn flow in gas/liquid flow was indicated. When the gas/solids flow rates are plotted on a gas/liquid flow pattern map, they fell in the churn flow region. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800868b Exemplaires
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Titre : Combined group-contribution and atom connectivity index-based methods for estimation of surface tension and viscosity Type de document : texte imprimé Auteurs : Elisa Conte, Auteur ; Ana Martinho, Auteur ; Henrique A. Matos, Auteur ; Rafiqul Gani, Auteur Année de publication : 2008 Article en page(s) : P. 7940-7954 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Surface tension Viscosity Atom connectivity (CI) Résumé : New methods for estimation of surface tension and viscosity of pure component organic chemicals are presented. The surface tension is estimated at 298 K while the viscosity is estimated at 300 K. For both properties, the combined group contribution−atom connectivity index approach has been employed, where the same set of experimental data is used for a group contribution (GC)-based model and an atom connectivity index (CI)-based method and then the model parameters for the atom-CI method are used to predict the missing parameters of the GC method. In this way, using the same set of experimental data, the application range of the GC method is enlarged through the combined GC−CI method. Group contributions for surface tension (98, 39, and 8 for first, second, and third order groups, respectively) and for viscosity (108, 39, and 12 for first, second, and third order groups, respectively) have been regressed using two collected sets of experimental data consisting of 420 compounds for surface tension and 445 for viscosity, including C, H, N, O, F, Cl, Br, and S atoms, some of which are complex polycyclic compounds. The new methods have been compared with other GC methods, and their use in mixture property models have also been highlighted through illustrative examples. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071572w
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7940-7954[article] Combined group-contribution and atom connectivity index-based methods for estimation of surface tension and viscosity [texte imprimé] / Elisa Conte, Auteur ; Ana Martinho, Auteur ; Henrique A. Matos, Auteur ; Rafiqul Gani, Auteur . - 2008 . - P. 7940-7954.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7940-7954
Mots-clés : Surface tension Viscosity Atom connectivity (CI) Résumé : New methods for estimation of surface tension and viscosity of pure component organic chemicals are presented. The surface tension is estimated at 298 K while the viscosity is estimated at 300 K. For both properties, the combined group contribution−atom connectivity index approach has been employed, where the same set of experimental data is used for a group contribution (GC)-based model and an atom connectivity index (CI)-based method and then the model parameters for the atom-CI method are used to predict the missing parameters of the GC method. In this way, using the same set of experimental data, the application range of the GC method is enlarged through the combined GC−CI method. Group contributions for surface tension (98, 39, and 8 for first, second, and third order groups, respectively) and for viscosity (108, 39, and 12 for first, second, and third order groups, respectively) have been regressed using two collected sets of experimental data consisting of 420 compounds for surface tension and 445 for viscosity, including C, H, N, O, F, Cl, Br, and S atoms, some of which are complex polycyclic compounds. The new methods have been compared with other GC methods, and their use in mixture property models have also been highlighted through illustrative examples. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071572w Exemplaires
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Titre : Correlation of mixture vapor-liquid equilibria with the SPEADMD model Type de document : texte imprimé Auteurs : Amir Vahid, Auteur ; Amanda D. Sans, Auteur ; J. Richard Elliott, Auteur Année de publication : 2008 Article en page(s) : P. 7955-7964 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Molecular simulation SPEADMD Vapor− Liquid Résumé : The present work examines the accuracy of the SPEADMD molecular simulation methodology in correlating experimental data relative to a standard low-pressure database for testing VLE models. The database contains 104 binary systems categorized according to polarity and ideality. Although the database is somewhat small, it covers a broad range of chemical functionality, including halocarbons and carboxylic acids as well as hydrocarbons and alcohols. Six models were tested and compared for their characterization of these mixtures. Four standard models were evaluated to establish a basis for comparison: the Margules, NRTL, PR, and PRWS models. The SPEADMD model was evaluated in three forms. In its elementary form, the SPEADMD model includes ∼10% deviations in vapor pressure because of the application of transferable potential functions in the molecular model. An alternative model is developed on the basis of SPEADMD combined with corrected vapor pressures and customized self-interaction parameter for pure compounds. This alternative is referred to as the SPEADCI model, in which CI stands for customized interactions. Results show that SPEADCI model provides accuracy similar to the NRTL and PRWS models, even though it includes only one adjustable parameter per binary system, whereas the NRTL model includes two and the PRWS models include three. Deviations in correlated bubble point pressure are roughly 1−2% for these models. The SPEADMD models have the advantage that transferable potentials can be applied for solvation interactions that are similar to the Kamlet-Taft interaction parameters. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800374h
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7955-7964[article] Correlation of mixture vapor-liquid equilibria with the SPEADMD model [texte imprimé] / Amir Vahid, Auteur ; Amanda D. Sans, Auteur ; J. Richard Elliott, Auteur . - 2008 . - P. 7955-7964.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7955-7964
Mots-clés : Molecular simulation SPEADMD Vapor− Liquid Résumé : The present work examines the accuracy of the SPEADMD molecular simulation methodology in correlating experimental data relative to a standard low-pressure database for testing VLE models. The database contains 104 binary systems categorized according to polarity and ideality. Although the database is somewhat small, it covers a broad range of chemical functionality, including halocarbons and carboxylic acids as well as hydrocarbons and alcohols. Six models were tested and compared for their characterization of these mixtures. Four standard models were evaluated to establish a basis for comparison: the Margules, NRTL, PR, and PRWS models. The SPEADMD model was evaluated in three forms. In its elementary form, the SPEADMD model includes ∼10% deviations in vapor pressure because of the application of transferable potential functions in the molecular model. An alternative model is developed on the basis of SPEADMD combined with corrected vapor pressures and customized self-interaction parameter for pure compounds. This alternative is referred to as the SPEADCI model, in which CI stands for customized interactions. Results show that SPEADCI model provides accuracy similar to the NRTL and PRWS models, even though it includes only one adjustable parameter per binary system, whereas the NRTL model includes two and the PRWS models include three. Deviations in correlated bubble point pressure are roughly 1−2% for these models. The SPEADMD models have the advantage that transferable potentials can be applied for solvation interactions that are similar to the Kamlet-Taft interaction parameters. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800374h Exemplaires
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