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Vol. 50 N° 8 - Avril 2011 [texte imprimé] . - 2011 . - p. 4217-4800 : ill. ; 28 cm. Chemical engineering Langues : Anglais (eng)
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Ajouter le résultat dans votre panierAdsorption and UV protection properties of the extract from honeysuckle onto wool / Sha-Sha Sun in Industrial & engineering chemistry research, Vol. 50 N° 8 (Avril 2011)
Titre : Adsorption and UV protection properties of the extract from honeysuckle onto wool Type de document : texte imprimé Auteurs : Sha-Sha Sun, Auteur ; Ren-Cheng Tang, Auteur Année de publication : 2011 Article en page(s) : pp. 4217–4224 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Adsorption Résumé : The adsorption and UV-protection properties of water-extract from honeysuckle whose main ingredient is chlorogenic acid onto wool were studied. The effect of initial pH on the adsorption was investigated, and the extent of adsorption was found to increase with decreasing pH in the range 2−7. Four kinetic equations, namely pseudo-first-order, pseudo-second-order, Elvoich, and intraparticle diffusion equations were employed to investigate the adsorption rates. The pseudo-second-order model provided the best fit to the experimental data and was indicated with the activation energy of 47.91 kJ mol−1. The equilibrium adsorption data were fitted by Freundlich, Langmuir, Redlich−Peterson, and Langmuir−Nernst isotherm models. The adsorption behavior accorded with Redlich−Peterson and Langmuir−Nernst models well. The honeysuckle extract showed good build-up properties, and the UV transmittance in the range of UVA and UVB of wool treated with honeysuckle extract decreased obviously while the ultraviolet protection factors increased. The extract of honeysuckle may be developed as a natural UV-absorbing agent applied to wool finishing. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101505q
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4217–4224[article] Adsorption and UV protection properties of the extract from honeysuckle onto wool [texte imprimé] / Sha-Sha Sun, Auteur ; Ren-Cheng Tang, Auteur . - 2011 . - pp. 4217–4224.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4217–4224
Mots-clés : Adsorption Résumé : The adsorption and UV-protection properties of water-extract from honeysuckle whose main ingredient is chlorogenic acid onto wool were studied. The effect of initial pH on the adsorption was investigated, and the extent of adsorption was found to increase with decreasing pH in the range 2−7. Four kinetic equations, namely pseudo-first-order, pseudo-second-order, Elvoich, and intraparticle diffusion equations were employed to investigate the adsorption rates. The pseudo-second-order model provided the best fit to the experimental data and was indicated with the activation energy of 47.91 kJ mol−1. The equilibrium adsorption data were fitted by Freundlich, Langmuir, Redlich−Peterson, and Langmuir−Nernst isotherm models. The adsorption behavior accorded with Redlich−Peterson and Langmuir−Nernst models well. The honeysuckle extract showed good build-up properties, and the UV transmittance in the range of UVA and UVB of wool treated with honeysuckle extract decreased obviously while the ultraviolet protection factors increased. The extract of honeysuckle may be developed as a natural UV-absorbing agent applied to wool finishing. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101505q Exemplaires
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Titre : Hydrothermal pretreatment of switchgrass Type de document : texte imprimé Auteurs : Zhoujian Hu, Auteur ; Arthur J. Ragauskas, Auteur Année de publication : 2011 Article en page(s) : pp.4225–4230 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydrothermal Résumé : Samples Alamo, Kanlow, GA993, and GA992 switchgrass, Panicum virgatum L., were partitioned into two morphological portions, leaves and internodes, and analyzed for chemical compositions in the previous study. These samples underwent a hydrothermal pretreatment, followed by cellulase and cellobiase treatment. Hydrothermal pretreatment was found to provide comparable gravimetric yields ranging from 48.1 to 51.4%. However, cellulose digestibility of the pretreated leaf portion of the switchgrass exhibited 32.5% greater glucose yield (77.4%) than that of the internode portion (44.9%). The carbohydrate profiles, cellulose crystal structure, and degree of polymerization (DP) of the cellulose were analyzed for native and pretreated leaves and internodes. The results demonstrated that pretreated leaves and internodes had similar chemical constituent profiles and chemical structure for cellulose and lignin but significant differences for the DP of α-cellulose. The lower DP of cellulose for the pretreated leaf portion of the switchgrass was attributed to be a factor for the enhanced cellulose digestibility in comparison with the internode portion. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101886d
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp.4225–4230[article] Hydrothermal pretreatment of switchgrass [texte imprimé] / Zhoujian Hu, Auteur ; Arthur J. Ragauskas, Auteur . - 2011 . - pp.4225–4230.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp.4225–4230
Mots-clés : Hydrothermal Résumé : Samples Alamo, Kanlow, GA993, and GA992 switchgrass, Panicum virgatum L., were partitioned into two morphological portions, leaves and internodes, and analyzed for chemical compositions in the previous study. These samples underwent a hydrothermal pretreatment, followed by cellulase and cellobiase treatment. Hydrothermal pretreatment was found to provide comparable gravimetric yields ranging from 48.1 to 51.4%. However, cellulose digestibility of the pretreated leaf portion of the switchgrass exhibited 32.5% greater glucose yield (77.4%) than that of the internode portion (44.9%). The carbohydrate profiles, cellulose crystal structure, and degree of polymerization (DP) of the cellulose were analyzed for native and pretreated leaves and internodes. The results demonstrated that pretreated leaves and internodes had similar chemical constituent profiles and chemical structure for cellulose and lignin but significant differences for the DP of α-cellulose. The lower DP of cellulose for the pretreated leaf portion of the switchgrass was attributed to be a factor for the enhanced cellulose digestibility in comparison with the internode portion. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101886d Exemplaires
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Titre : Vapor-pressure measurements and modeling of dipentaerythritol ester lubricants Type de document : texte imprimé Auteurs : Josefa Garcia, Auteur ; Ramy Abou Naccoul, Auteur ; Josefa Fernandez, Auteur Année de publication : 2011 Article en page(s) : pp. 4231–4237 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Lubricants Vapor pressure measurements Résumé : The aim of this work is to present new vapor-pressure measurements and provide a good description of the volumetric and phase behavior of dipentaerythritol ester (DiPEs) lubricants, using the Statistical Associating Fluid Theory (SAFT) model (PC-SAFT and SAFT-VR versions). Characteristic parameters of these versions were optimized for dipentaerythritol hexapentanoate (DiPEC5), dipentaerythritol hexaheptanoate (DiPEC7), and dipentaerythritol isononanoate (DiPEiC9), using experimental vapor pressures and densities. With these parameters, compressed densities were predicted. Experimental vapor pressures, determined by a gas saturation apparatus, range between 2 × 10−5 Pa and 16 Pa, whereas the absolute deviations obtained in the correlations for both versions of the model (PC-SAFT and SAFT-VR) are between 10−6 Pa and 1 Pa. In the case of saturated densities, the average absolute deviation (AAD) values, for both models, range from 0.2% to 1.3%, except for DiPEC7, where the AAD is 4.4% when using the SAFT-VR model. The SAFT-VR version gives slightly better correlations, although we must note that this version has four parameters, whereas the PC-SAFT version has three. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102166r
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4231–4237[article] Vapor-pressure measurements and modeling of dipentaerythritol ester lubricants [texte imprimé] / Josefa Garcia, Auteur ; Ramy Abou Naccoul, Auteur ; Josefa Fernandez, Auteur . - 2011 . - pp. 4231–4237.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4231–4237
Mots-clés : Lubricants Vapor pressure measurements Résumé : The aim of this work is to present new vapor-pressure measurements and provide a good description of the volumetric and phase behavior of dipentaerythritol ester (DiPEs) lubricants, using the Statistical Associating Fluid Theory (SAFT) model (PC-SAFT and SAFT-VR versions). Characteristic parameters of these versions were optimized for dipentaerythritol hexapentanoate (DiPEC5), dipentaerythritol hexaheptanoate (DiPEC7), and dipentaerythritol isononanoate (DiPEiC9), using experimental vapor pressures and densities. With these parameters, compressed densities were predicted. Experimental vapor pressures, determined by a gas saturation apparatus, range between 2 × 10−5 Pa and 16 Pa, whereas the absolute deviations obtained in the correlations for both versions of the model (PC-SAFT and SAFT-VR) are between 10−6 Pa and 1 Pa. In the case of saturated densities, the average absolute deviation (AAD) values, for both models, range from 0.2% to 1.3%, except for DiPEC7, where the AAD is 4.4% when using the SAFT-VR model. The SAFT-VR version gives slightly better correlations, although we must note that this version has four parameters, whereas the PC-SAFT version has three. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102166r Exemplaires
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Titre : Performan!ce of a wet flue gas desulfurization pilot plant under oxy-fuel conditions Type de document : texte imprimé Auteurs : Brian B. Hansen, Auteur ; Folmer Fogh, Auteur ; Niels Ole Knudsen, Auteur Année de publication : 2011 Article en page(s) : pp. 4238–4244 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Gas Desulfurization Oxy fuel Résumé : Oxy-fuel firing is a promising technology that should enable the capture and storage of anthropogenic CO2 emissions from large stationary sources such as power plants and heavy industry. However, this new technology has a high energy demand for air separation and CO2 compression and storage. Unresolved issues, such as determination of the optimal recycle location of flue gas, the flue gas cleaning steps required (SO2, NOx, and particles), and the impact of an oxy-fuel flue gas on the cleaning steps, also persist. The aim of this work was to study the performance of the wet flue gas desulfurization (FGD) process under operating conditions corresponding to oxy-fuel firing. The most important output parameters were the overall degree of desulfurization and the residual limestone concentration in the gypsum slurry. Pilot-scale experiments quantified that the introduction of a flue gas with 90 vol % CO2, at a holding tank pH 5.4, reduced the limestone dissolution rate significantly and thereby increased the residual, particulate limestone concentration in the gypsum slurry from 3.2 to 5.0 g/L slurry relative to a base-case (air-firing) experiment with a flue gas CO2 concentration around 7 vol %. In the same experiment, due to the higher residual limestone concentration, the degree of desulfurization increased from 91 to 94%. The addition of 10 mM adipic acid to the slurry was not sufficient to return the increased concentration of residual limestone to the base-case level, but an additional increase in desulfurization degree, from 94 to 97%, was obtained. Using a holding tank pH 5.0 (no adipic acid) returned both parameters to the levels observed in the base-case experiment. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1022173
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4238–4244[article] Performan!ce of a wet flue gas desulfurization pilot plant under oxy-fuel conditions [texte imprimé] / Brian B. Hansen, Auteur ; Folmer Fogh, Auteur ; Niels Ole Knudsen, Auteur . - 2011 . - pp. 4238–4244.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4238–4244
Mots-clés : Gas Desulfurization Oxy fuel Résumé : Oxy-fuel firing is a promising technology that should enable the capture and storage of anthropogenic CO2 emissions from large stationary sources such as power plants and heavy industry. However, this new technology has a high energy demand for air separation and CO2 compression and storage. Unresolved issues, such as determination of the optimal recycle location of flue gas, the flue gas cleaning steps required (SO2, NOx, and particles), and the impact of an oxy-fuel flue gas on the cleaning steps, also persist. The aim of this work was to study the performance of the wet flue gas desulfurization (FGD) process under operating conditions corresponding to oxy-fuel firing. The most important output parameters were the overall degree of desulfurization and the residual limestone concentration in the gypsum slurry. Pilot-scale experiments quantified that the introduction of a flue gas with 90 vol % CO2, at a holding tank pH 5.4, reduced the limestone dissolution rate significantly and thereby increased the residual, particulate limestone concentration in the gypsum slurry from 3.2 to 5.0 g/L slurry relative to a base-case (air-firing) experiment with a flue gas CO2 concentration around 7 vol %. In the same experiment, due to the higher residual limestone concentration, the degree of desulfurization increased from 91 to 94%. The addition of 10 mM adipic acid to the slurry was not sufficient to return the increased concentration of residual limestone to the base-case level, but an additional increase in desulfurization degree, from 94 to 97%, was obtained. Using a holding tank pH 5.0 (no adipic acid) returned both parameters to the levels observed in the base-case experiment. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1022173 Exemplaires
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Titre : Evaluating the probabilities of fluidization regimes Type de document : texte imprimé Auteurs : Milad Aghabararnejad, Auteur ; Navid Mostoufi, Auteur ; Rahmat Sotudeh-Gharebagh, Auteur Année de publication : 2011 Article en page(s) : pp. 4245–4251 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Probabilities fluidization regimes Résumé : Probabilities of fluidization regimes were determined experimentally using frequency domain analysis of pressure fluctuation data. It was assumed that regime transition does not occur at a distinct gas velocity and fluidization regimes coexist at each gas velocity. Three different flow structures (macro-, meso-, and microstructures) were recognized in a fluidized bed. Macrostructure is represented by bubbles, mesostructures are represented by clusters, and microstructure is represented by particles. These structures are the characteristics of bubbling, turbulent, and fast fluidization regimes. Regime probabilities were determined using power spectrum energies of these structures. Experiments were carried out in a 1 m high and 5 cm inner diameter glass column. Pressure fluctuations were measured using a piezoresistive pressure sensor. Sand particles with various diameters (150, 280, and 490 μm) and fluid catalytic cracking (FCC) particles (73 μm) were used as solids. Probabilities of fluidization regimes were calculated at various gas velocities. A new procedure was proposed for evaluating the regime probabilities versus gas velocity. It was shown that the proposed correlation is in good agreement with the experimental data and is noticeably better than the method proposed in the literature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100642b
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4245–4251[article] Evaluating the probabilities of fluidization regimes [texte imprimé] / Milad Aghabararnejad, Auteur ; Navid Mostoufi, Auteur ; Rahmat Sotudeh-Gharebagh, Auteur . - 2011 . - pp. 4245–4251.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4245–4251
Mots-clés : Probabilities fluidization regimes Résumé : Probabilities of fluidization regimes were determined experimentally using frequency domain analysis of pressure fluctuation data. It was assumed that regime transition does not occur at a distinct gas velocity and fluidization regimes coexist at each gas velocity. Three different flow structures (macro-, meso-, and microstructures) were recognized in a fluidized bed. Macrostructure is represented by bubbles, mesostructures are represented by clusters, and microstructure is represented by particles. These structures are the characteristics of bubbling, turbulent, and fast fluidization regimes. Regime probabilities were determined using power spectrum energies of these structures. Experiments were carried out in a 1 m high and 5 cm inner diameter glass column. Pressure fluctuations were measured using a piezoresistive pressure sensor. Sand particles with various diameters (150, 280, and 490 μm) and fluid catalytic cracking (FCC) particles (73 μm) were used as solids. Probabilities of fluidization regimes were calculated at various gas velocities. A new procedure was proposed for evaluating the regime probabilities versus gas velocity. It was shown that the proposed correlation is in good agreement with the experimental data and is noticeably better than the method proposed in the literature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100642b Exemplaires
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Titre : Finding the simplest mechanistic kinetic model describing the homogeneous catalytic hydrogenation of avermectin to ivermectin Type de document : texte imprimé Auteurs : Mariano D. Cristaldi, Auteur ; Maria I. Cabrera, Auteur ; Ernesto C. Martinez, Auteur Année de publication : 2011 Article en page(s) : pp. 4252–4263 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetic Catalytic hydrogenation Résumé : Six mechanistic kinetic models of increasing complexity are analyzed to describe the RhCl(Ph3P)3 catalyzed hydrogenation process to produce ivermectin from avermectins B1a and B1b. Global sensitivity analysis (GSA) usefulness for selecting the simplest and the most suitable model is shown. First-order and total effect sensitivity indices for model parameters computed from GSA have been used for establishing those elementary reaction steps which were the most important in an extensive reaction framework. The prediction capability of the chosen model is corroborated by comparing its predictions with experimental data from both a lab-scale reactor and an industrial-scale reactor operating under isothermal and nonisothermal conditions, respectively. The best model is simple to use while resulting in a significant computational effort saving because there is no need to perform iterative algorithms for solving model equations. Another interesting feature is that ODEs for such a model have an analytical solution for isothermal hydrogenation processes. These features make modeling more amenable for cost-effective simulation and to include the selected model into computational frameworks for design of the hydrogenation process and control systems of the most usual catalytic method for producing ivermectin. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101289h
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4252–4263[article] Finding the simplest mechanistic kinetic model describing the homogeneous catalytic hydrogenation of avermectin to ivermectin [texte imprimé] / Mariano D. Cristaldi, Auteur ; Maria I. Cabrera, Auteur ; Ernesto C. Martinez, Auteur . - 2011 . - pp. 4252–4263.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4252–4263
Mots-clés : Kinetic Catalytic hydrogenation Résumé : Six mechanistic kinetic models of increasing complexity are analyzed to describe the RhCl(Ph3P)3 catalyzed hydrogenation process to produce ivermectin from avermectins B1a and B1b. Global sensitivity analysis (GSA) usefulness for selecting the simplest and the most suitable model is shown. First-order and total effect sensitivity indices for model parameters computed from GSA have been used for establishing those elementary reaction steps which were the most important in an extensive reaction framework. The prediction capability of the chosen model is corroborated by comparing its predictions with experimental data from both a lab-scale reactor and an industrial-scale reactor operating under isothermal and nonisothermal conditions, respectively. The best model is simple to use while resulting in a significant computational effort saving because there is no need to perform iterative algorithms for solving model equations. Another interesting feature is that ODEs for such a model have an analytical solution for isothermal hydrogenation processes. These features make modeling more amenable for cost-effective simulation and to include the selected model into computational frameworks for design of the hydrogenation process and control systems of the most usual catalytic method for producing ivermectin. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101289h Exemplaires
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Titre : New approach for kinetic modeling of catalytic cracking of paraffinic naphtha Type de document : texte imprimé Auteurs : Jae Ho Lee, Auteur ; Sookil Kang, Auteur ; Young Kim, Auteur Année de publication : 2011 Article en page(s) : pp. 4264–4279 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetic Catalytic cracking Résumé : Catalytic cracking of paraffinic naphtha requires higher temperature than that for cracking of olefinic naphtha. In the high temperature catalytic cracking, thermal cracking also occurs simultaneously. The degree of thermal cracking and its contribution to ethylene and propylene yield in the catalytic cracking of paraffinic naphtha are experimentally investigated. As the degree of thermal cracking is high at over 650 °C, both thermal and catalytic cracking mechanisms have to be simultaneously considered in the kinetic model. An approximate approach based on transition state theory is proposed for kinetic modeling of the catalytic cracking of paraffinic naphtha, which has a complex chemical reaction network. The pertinent parameters of the developed kinetic model are estimated by a genetic algorithm. Additionally, an integrated modeling software package is developed with a graphical user interface. The efficacy of the proposed approach is shown with its application to industrial catalytic cracking of paraffinic naphtha in the circulating fluidized bed reactor system. This approach will be particularly effective for modeling complex chemical reaction network systems. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1014074
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4264–4279[article] New approach for kinetic modeling of catalytic cracking of paraffinic naphtha [texte imprimé] / Jae Ho Lee, Auteur ; Sookil Kang, Auteur ; Young Kim, Auteur . - 2011 . - pp. 4264–4279.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4264–4279
Mots-clés : Kinetic Catalytic cracking Résumé : Catalytic cracking of paraffinic naphtha requires higher temperature than that for cracking of olefinic naphtha. In the high temperature catalytic cracking, thermal cracking also occurs simultaneously. The degree of thermal cracking and its contribution to ethylene and propylene yield in the catalytic cracking of paraffinic naphtha are experimentally investigated. As the degree of thermal cracking is high at over 650 °C, both thermal and catalytic cracking mechanisms have to be simultaneously considered in the kinetic model. An approximate approach based on transition state theory is proposed for kinetic modeling of the catalytic cracking of paraffinic naphtha, which has a complex chemical reaction network. The pertinent parameters of the developed kinetic model are estimated by a genetic algorithm. Additionally, an integrated modeling software package is developed with a graphical user interface. The efficacy of the proposed approach is shown with its application to industrial catalytic cracking of paraffinic naphtha in the circulating fluidized bed reactor system. This approach will be particularly effective for modeling complex chemical reaction network systems. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1014074 Exemplaires
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Titre : Influence of lanthanum addition on catalytic properties of PtSnK/Al2O3 catalyst for isobutane dehydrogenation Type de document : texte imprimé Auteurs : Lihui Wan, Auteur ; Yuming Zhou, Auteur ; Yiwei Zhang, Auteur Année de publication : 2011 Article en page(s) : pp. 4280–4285 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalytic properties Résumé : The effect of lanthanum addition on catalytic properties of PtSnK/Al2O3 catalyst for isobutane dehydrogenation was investigated. The catalysts were characterized by nitrogen adsorption, H2 chemisorption, XRF, XRD, XPS, TG, TPO, and NH3-TPD. Results showed that with the appropriate addition of lanthanum, the platinum dispersion increased, and carbon depositions decreased. The presence of La in the PtSnK/Al2O3 catalysts could not only strengthen the Sn−Al2O3 interaction, but also stabilize the oxidation states of Sn species, thus increasing the reaction activity and stability. Among the catalysts investigated, PtSnKLa(0.9 wt %)/Al2O3 had the best catalytic performance. After reaction for 8 h, the isobutane conversion of 49% was achieved with the corresponding isobutene selectivity of higher than 95%. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1023518
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4280–4285[article] Influence of lanthanum addition on catalytic properties of PtSnK/Al2O3 catalyst for isobutane dehydrogenation [texte imprimé] / Lihui Wan, Auteur ; Yuming Zhou, Auteur ; Yiwei Zhang, Auteur . - 2011 . - pp. 4280–4285.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4280–4285
Mots-clés : Catalytic properties Résumé : The effect of lanthanum addition on catalytic properties of PtSnK/Al2O3 catalyst for isobutane dehydrogenation was investigated. The catalysts were characterized by nitrogen adsorption, H2 chemisorption, XRF, XRD, XPS, TG, TPO, and NH3-TPD. Results showed that with the appropriate addition of lanthanum, the platinum dispersion increased, and carbon depositions decreased. The presence of La in the PtSnK/Al2O3 catalysts could not only strengthen the Sn−Al2O3 interaction, but also stabilize the oxidation states of Sn species, thus increasing the reaction activity and stability. Among the catalysts investigated, PtSnKLa(0.9 wt %)/Al2O3 had the best catalytic performance. After reaction for 8 h, the isobutane conversion of 49% was achieved with the corresponding isobutene selectivity of higher than 95%. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1023518 Exemplaires
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Titre : Characterization of fast pyrolysis of dry distiller’s grains (DDGS) and palm kernel cake using a heated foil reactor : nitrogen chemistry and basic reactor modeling Type de document : texte imprimé Auteurs : Jacopo Giuntoli, Auteur ; Jeroen Gout, Auteur ; Adrian H. M. Verkooijen, Auteur Année de publication : 2011 Article en page(s) : pp. 4286–4300 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Pyrolysis Résumé : In this paper, two residues of liquid biofuels production were tested: dry distiller’s grains with solubles and palm kernel cake. The fuels were tested in a heated foil reactor inserted in a Fourier Transform Infrared spectrometer under fast pyrolysis conditions: a heating rate of 600 °C/s and final temperatures ranging from 500 to 1300 °C. The fuels were also pretreated by water leaching to remove water-soluble inorganic compounds. A numerical model of the unloaded system was developed to gain better insight into the temperature and velocity profiles in the reactor and on the foil. The model allowed the detection of zones of high temperature and low velocity around the hot foil, indicating that secondary reactions are likely. Moreover, temperature validation with an InfraRed pyrometer indicated that the temperature measured by the control thermocouple is on average about 15% (in °C) lower than the actual foil temperature. The product composition and final yields of volatile species were measured at different final temperatures. The main volatile species was CO2 for temperatures lower than 1000 °C. At higher temperatures CO became the most abundant volatile species, likely because of tar cracking. HCN resulted to be the main volatile-N compound for all samples at all temperatures, while NH3 was detected in minor amounts. The mechanism of decomposition of proteins seems to have changed from deamination, at slow heating rates, to dehydration, followed by the formation of cyclic amides. These structures were released as tar-N and subsequently decomposed into HCN and NH3. The effect of the leaching was not relevant for weight loss and main species release, but it appeared to enhance tar-N decomposition for the DDGS sample. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101618c
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4286–4300[article] Characterization of fast pyrolysis of dry distiller’s grains (DDGS) and palm kernel cake using a heated foil reactor : nitrogen chemistry and basic reactor modeling [texte imprimé] / Jacopo Giuntoli, Auteur ; Jeroen Gout, Auteur ; Adrian H. M. Verkooijen, Auteur . - 2011 . - pp. 4286–4300.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4286–4300
Mots-clés : Pyrolysis Résumé : In this paper, two residues of liquid biofuels production were tested: dry distiller’s grains with solubles and palm kernel cake. The fuels were tested in a heated foil reactor inserted in a Fourier Transform Infrared spectrometer under fast pyrolysis conditions: a heating rate of 600 °C/s and final temperatures ranging from 500 to 1300 °C. The fuels were also pretreated by water leaching to remove water-soluble inorganic compounds. A numerical model of the unloaded system was developed to gain better insight into the temperature and velocity profiles in the reactor and on the foil. The model allowed the detection of zones of high temperature and low velocity around the hot foil, indicating that secondary reactions are likely. Moreover, temperature validation with an InfraRed pyrometer indicated that the temperature measured by the control thermocouple is on average about 15% (in °C) lower than the actual foil temperature. The product composition and final yields of volatile species were measured at different final temperatures. The main volatile species was CO2 for temperatures lower than 1000 °C. At higher temperatures CO became the most abundant volatile species, likely because of tar cracking. HCN resulted to be the main volatile-N compound for all samples at all temperatures, while NH3 was detected in minor amounts. The mechanism of decomposition of proteins seems to have changed from deamination, at slow heating rates, to dehydration, followed by the formation of cyclic amides. These structures were released as tar-N and subsequently decomposed into HCN and NH3. The effect of the leaching was not relevant for weight loss and main species release, but it appeared to enhance tar-N decomposition for the DDGS sample. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101618c Exemplaires
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Titre : Catalyzed partial oxidative gasification of phenol in supercritical water Type de document : texte imprimé Auteurs : DongHai Xu, Auteur ; ShuZhong Wang, Auteur ; Yang Guo, Auteur Année de publication : 2011 Article en page(s) : pp. 4301–4307 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Gasification Résumé : Phenol, a substance difficult to be gasified, is often an intermediate product from biomass gasification in supercritical water. In this study, 1 wt % phenol is gasified in supercritical water with different oxidation coefficients (0 ≤ n ≤ 0.8) at 430−550 °C, 25 MPa in a continuous tubular-flow reaction plant with or without 0.1 wt % Na2CO3. The results show that TOC (total organic carbon) removal rate and COD (chemical oxygen demand) removal rate of reactor effluent will rise with the increase of oxidation coefficient and reaction temperature. When n rises from 0.3 to 0.8 at 500 °C, hydrogen yield and hydrogen molar fraction will first increase and then decrease. They reach their respective maximum values of 0.245 mol/mol and 46.2% at n = 0.6 with the residence time of 2.96 min. There is an appropriate oxidation coefficient for obtaining the highest hydrogen yield for phenol supercritical water partial oxidative gasification (SWPO). Na2CO3 can serve as a catalyst or an additive for phenol SWPO. When 0.1 wt % Na2CO3 is added, hydrogen yield is near 0.477 mol/mol at n = 0.6, 500 °C with the residence time of 2.96 min. Furthermore, the potential conversion pathways for phenol SWPO with Na2CO3 catalyst are also proposed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1016255
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4301–4307[article] Catalyzed partial oxidative gasification of phenol in supercritical water [texte imprimé] / DongHai Xu, Auteur ; ShuZhong Wang, Auteur ; Yang Guo, Auteur . - 2011 . - pp. 4301–4307.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4301–4307
Mots-clés : Gasification Résumé : Phenol, a substance difficult to be gasified, is often an intermediate product from biomass gasification in supercritical water. In this study, 1 wt % phenol is gasified in supercritical water with different oxidation coefficients (0 ≤ n ≤ 0.8) at 430−550 °C, 25 MPa in a continuous tubular-flow reaction plant with or without 0.1 wt % Na2CO3. The results show that TOC (total organic carbon) removal rate and COD (chemical oxygen demand) removal rate of reactor effluent will rise with the increase of oxidation coefficient and reaction temperature. When n rises from 0.3 to 0.8 at 500 °C, hydrogen yield and hydrogen molar fraction will first increase and then decrease. They reach their respective maximum values of 0.245 mol/mol and 46.2% at n = 0.6 with the residence time of 2.96 min. There is an appropriate oxidation coefficient for obtaining the highest hydrogen yield for phenol supercritical water partial oxidative gasification (SWPO). Na2CO3 can serve as a catalyst or an additive for phenol SWPO. When 0.1 wt % Na2CO3 is added, hydrogen yield is near 0.477 mol/mol at n = 0.6, 500 °C with the residence time of 2.96 min. Furthermore, the potential conversion pathways for phenol SWPO with Na2CO3 catalyst are also proposed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1016255 Exemplaires
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Titre : Effect of structural and preparation parameters on the activity and hydrothermal stability of metal-exchanged ZSM-5 in the selective catalytic reduction of NO by NH3 Type de document : texte imprimé Auteurs : Sandro Brandenberger, Auteur ; Oliver Krocher, Auteur ; Arno Tissler, Auteur Année de publication : 2011 Article en page(s) : pp. 4308–4319 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydrothermal Catalytic Résumé : The influence of the nature of metal ion, framework type, exchange method and exchange degree, the addition of NO2 to the gas flow and the introduction of Al, Nb, and Mn on the selective catalytic reduction (SCR) of NOx with ammonia over ZSM-5 and BEA catalysts was studied before and after hydrothermal aging. From the results, it was concluded that the stability of metal-exchanged zeolites is governed by the framework type, among which Fe−BEA showed superior hydrothermal stability, Cu−ZSM-5 and Fe−ZSM-5 showed medium hydrothermal stability, and Cu−BEA showed relatively low hydrothermal stability. The choice of the exchange metal was a key factor for the activity of the zeolite, whereas Cu showed high low-temperature activity and Fe showed high high-temperature activity in the SCR reaction. Simultaneously exchanged Fe/Cu−ZSM-5 combined the advantages of both exchange metals in one catalyst. The Si/Al ratio did not directly influence the activity or stability. The initial activity was not influenced by the exchange method, but with respect to stability, the chemical vapor ion-exchange method was clearly favored. However, in view of ease of catalyst preparation, liquid phase ion exchange and solid state ion exchange are the preferred methods. By feeding an NO/NO2 = 1:1 mixture, the SCR activity is increased by a factor of about 10−30 for fresh Fe−ZSM-5W (0.3) and about 30−100 for aged Fe−ZSM-5W (0.3) compared to only NO. The introduction of extraframework Al in ZSM-5 zeolites and the use of an Fe3+ metal salt as a precursor improved the stability of the Fe−ZSM-5 zeolites against hydrothermal aging in terms of the SCR activity. On the other hand, neither the introduction of Nb or La nor the simultaneous exchange of Mn and Fe enhanced the NO conversion after aging. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101771e
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4308–4319[article] Effect of structural and preparation parameters on the activity and hydrothermal stability of metal-exchanged ZSM-5 in the selective catalytic reduction of NO by NH3 [texte imprimé] / Sandro Brandenberger, Auteur ; Oliver Krocher, Auteur ; Arno Tissler, Auteur . - 2011 . - pp. 4308–4319.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4308–4319
Mots-clés : Hydrothermal Catalytic Résumé : The influence of the nature of metal ion, framework type, exchange method and exchange degree, the addition of NO2 to the gas flow and the introduction of Al, Nb, and Mn on the selective catalytic reduction (SCR) of NOx with ammonia over ZSM-5 and BEA catalysts was studied before and after hydrothermal aging. From the results, it was concluded that the stability of metal-exchanged zeolites is governed by the framework type, among which Fe−BEA showed superior hydrothermal stability, Cu−ZSM-5 and Fe−ZSM-5 showed medium hydrothermal stability, and Cu−BEA showed relatively low hydrothermal stability. The choice of the exchange metal was a key factor for the activity of the zeolite, whereas Cu showed high low-temperature activity and Fe showed high high-temperature activity in the SCR reaction. Simultaneously exchanged Fe/Cu−ZSM-5 combined the advantages of both exchange metals in one catalyst. The Si/Al ratio did not directly influence the activity or stability. The initial activity was not influenced by the exchange method, but with respect to stability, the chemical vapor ion-exchange method was clearly favored. However, in view of ease of catalyst preparation, liquid phase ion exchange and solid state ion exchange are the preferred methods. By feeding an NO/NO2 = 1:1 mixture, the SCR activity is increased by a factor of about 10−30 for fresh Fe−ZSM-5W (0.3) and about 30−100 for aged Fe−ZSM-5W (0.3) compared to only NO. The introduction of extraframework Al in ZSM-5 zeolites and the use of an Fe3+ metal salt as a precursor improved the stability of the Fe−ZSM-5 zeolites against hydrothermal aging in terms of the SCR activity. On the other hand, neither the introduction of Nb or La nor the simultaneous exchange of Mn and Fe enhanced the NO conversion after aging. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101771e Exemplaires
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Titre : Numerical analysis of the effect of gas sparging on bubble column hydrodynamics Type de document : texte imprimé Auteurs : Wei Bai, Auteur ; Niels G. Deen, Auteur ; J. A. M. Kuipers, Auteur Année de publication : 2011 Article en page(s) : pp. 4320–4328 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Numerical analysis Gas Résumé : A discrete bubble model (DBM) has been used to study the effect of gas sparger properties on the hydrodynamics in a bubble column. As a first step the performance of the model was evaluated by comparison with experimental data. Subsequently, four different perforated plates with different sparged areas were used as a gas sparger. Distributions of liquid velocity, turbulent kinetic energy, and void fraction in the central plane were compared for the four different systems. Furthermore, the effect of the sparger location was also investigated. It was found that the liquid-phase circulation becomes more pronounced as the sparged area location is more distant from the center of the bottom plate. Finally, gas-phase residence time distributions (RTD) were obtained from the simulations. By employing standard axial dispersion model, the gas-phase mixing in the bubble column was characterized. Results show that the extent of mixing increased when the sparged area decreased. The axial dispersion coefficient increased as the sparged area was shifted to the edge of the bottom plate. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1017805
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4320–4328[article] Numerical analysis of the effect of gas sparging on bubble column hydrodynamics [texte imprimé] / Wei Bai, Auteur ; Niels G. Deen, Auteur ; J. A. M. Kuipers, Auteur . - 2011 . - pp. 4320–4328.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4320–4328
Mots-clés : Numerical analysis Gas Résumé : A discrete bubble model (DBM) has been used to study the effect of gas sparger properties on the hydrodynamics in a bubble column. As a first step the performance of the model was evaluated by comparison with experimental data. Subsequently, four different perforated plates with different sparged areas were used as a gas sparger. Distributions of liquid velocity, turbulent kinetic energy, and void fraction in the central plane were compared for the four different systems. Furthermore, the effect of the sparger location was also investigated. It was found that the liquid-phase circulation becomes more pronounced as the sparged area location is more distant from the center of the bottom plate. Finally, gas-phase residence time distributions (RTD) were obtained from the simulations. By employing standard axial dispersion model, the gas-phase mixing in the bubble column was characterized. Results show that the extent of mixing increased when the sparged area decreased. The axial dispersion coefficient increased as the sparged area was shifted to the edge of the bottom plate. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1017805 Exemplaires
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Titre : Radial dispersion in liquid upflow through solid SiC foams Type de document : texte imprimé Auteurs : Tri Truong Huu, Auteur ; Regis Philippe, Auteur ; Patrick Nguyen, Auteur Année de publication : 2011 Article en page(s) : pp. 4329–4334 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Radial dispersion Résumé : The radial dispersion process of an inert tracer in an upward liquid flow (superficial velocity from 3 × 10−3 to 13 × 10−3 m·s−1) through high-porosity (0.85 and 0.90 void fractions) solid foam samples of various lengths (6−15 cm) has been investigated. As in a standard packed bed the radial Peclet number based on the “cell diameter” is found to be of the order of 10 when the process is governed by mechanical dispersion. The results are in agreement with the flow contribution to the effective radial heat conductivity measured independently on the same type of foams. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1017942
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4329–4334[article] Radial dispersion in liquid upflow through solid SiC foams [texte imprimé] / Tri Truong Huu, Auteur ; Regis Philippe, Auteur ; Patrick Nguyen, Auteur . - 2011 . - pp. 4329–4334.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4329–4334
Mots-clés : Radial dispersion Résumé : The radial dispersion process of an inert tracer in an upward liquid flow (superficial velocity from 3 × 10−3 to 13 × 10−3 m·s−1) through high-porosity (0.85 and 0.90 void fractions) solid foam samples of various lengths (6−15 cm) has been investigated. As in a standard packed bed the radial Peclet number based on the “cell diameter” is found to be of the order of 10 when the process is governed by mechanical dispersion. The results are in agreement with the flow contribution to the effective radial heat conductivity measured independently on the same type of foams. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1017942 Exemplaires
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Titre : Dynamics of mixing-limited pattern formation in nonisothermal homogeneous autocatalytic reactors : a low-dimensional computational analysis Type de document : texte imprimé Auteurs : Anwesha Chaudhury, Auteur ; Saikat Chakraborty, Auteur Année de publication : 2011 Article en page(s) : pp. 4335–4344 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Dynamics Homogeneous autocatalytic reactors Résumé : This work studies the temporal evolution of concentration and temperature patterns in fast, homogeneous, nonisothermal, autocatalytic, adiabatic tubular reactors. Transverse patterns are simulated using a two-dimensional unsteady-state model, called the regularized model, obtained by averaging the 3-D convection−diffusion−reaction equations axially using a Liapunov−Schmidt based averaging technique, followed by regularization. Steady state bifurcation and linear stability analysis show that the patterns emerge from the unstable middle branch of the S-shaped steady state bifurcation diagrams of concentration/temperature versus reactor Damkohler number. This unstable steady state is then slightly perturbed to analyze the evolution dynamics of various symmetric and asymmetric concentration and temperature patterns. Our simulations show how zones with slightly differing concentrations and temperature evolve over time into intensely segregated patterns that slowly diffuse into the homogeneous ignited branch of the steady state curve. Our parametric analysis quantifies the effects of process parameters such as transverse and axial Peclet numbers, Damkohler number, Zeldovich number, and Lewis number on the dynamics and intensity of pattern formation and dissolution. Interesting differences between the mechanics of pattern formation in isothermal and nonisothermal autocatalysis are also discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101861x
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4335–4344[article] Dynamics of mixing-limited pattern formation in nonisothermal homogeneous autocatalytic reactors : a low-dimensional computational analysis [texte imprimé] / Anwesha Chaudhury, Auteur ; Saikat Chakraborty, Auteur . - 2011 . - pp. 4335–4344.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4335–4344
Mots-clés : Dynamics Homogeneous autocatalytic reactors Résumé : This work studies the temporal evolution of concentration and temperature patterns in fast, homogeneous, nonisothermal, autocatalytic, adiabatic tubular reactors. Transverse patterns are simulated using a two-dimensional unsteady-state model, called the regularized model, obtained by averaging the 3-D convection−diffusion−reaction equations axially using a Liapunov−Schmidt based averaging technique, followed by regularization. Steady state bifurcation and linear stability analysis show that the patterns emerge from the unstable middle branch of the S-shaped steady state bifurcation diagrams of concentration/temperature versus reactor Damkohler number. This unstable steady state is then slightly perturbed to analyze the evolution dynamics of various symmetric and asymmetric concentration and temperature patterns. Our simulations show how zones with slightly differing concentrations and temperature evolve over time into intensely segregated patterns that slowly diffuse into the homogeneous ignited branch of the steady state curve. Our parametric analysis quantifies the effects of process parameters such as transverse and axial Peclet numbers, Damkohler number, Zeldovich number, and Lewis number on the dynamics and intensity of pattern formation and dissolution. Interesting differences between the mechanics of pattern formation in isothermal and nonisothermal autocatalysis are also discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101861x Exemplaires
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Titre : Influence of the competitive adsorbates on the catalytic properties of PtSnNaMg/ZSM-5 catalysts for propane dehydrogenation Type de document : texte imprimé Auteurs : Linyang Bai, Auteur ; Yuming Zhou, Auteur ; Yiwei Zhang, Auteur Année de publication : 2011 Article en page(s) : pp. 4345–4350 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalytic properties Résumé : This paper is aimed at studying the influence of the competitive adsorbates (HCl, lactic acid, and citric acid) on the structural and catalytic properties of PtSnNaMg/ZSM-5 catalysts for propane dehydrogenation. N2 adsorption, X-ray diffraction, inductively coupled plasma, NH3 temperature-programmed desorption, H2 temperature-programmed reduction and transmission electron microscopy were applied for characterization of the prepared catalysts. The catalytic performance was tested in a microreactor. The obtained results indicate that the catalyst prepared in HCl medium exhibited the best catalytic activity and stability due to relatively better metal distribution on the support and/or the strong interactions between Pt and Sn as well as between them and the support. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1018639
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4345–4350[article] Influence of the competitive adsorbates on the catalytic properties of PtSnNaMg/ZSM-5 catalysts for propane dehydrogenation [texte imprimé] / Linyang Bai, Auteur ; Yuming Zhou, Auteur ; Yiwei Zhang, Auteur . - 2011 . - pp. 4345–4350.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4345–4350
Mots-clés : Catalytic properties Résumé : This paper is aimed at studying the influence of the competitive adsorbates (HCl, lactic acid, and citric acid) on the structural and catalytic properties of PtSnNaMg/ZSM-5 catalysts for propane dehydrogenation. N2 adsorption, X-ray diffraction, inductively coupled plasma, NH3 temperature-programmed desorption, H2 temperature-programmed reduction and transmission electron microscopy were applied for characterization of the prepared catalysts. The catalytic performance was tested in a microreactor. The obtained results indicate that the catalyst prepared in HCl medium exhibited the best catalytic activity and stability due to relatively better metal distribution on the support and/or the strong interactions between Pt and Sn as well as between them and the support. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1018639 Exemplaires
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Titre : Kinetics and simulation including mass-transfer processes of direct H2O2 synthesis from H2 and O2 over Pd/C catalyst in water containing H+ and Br− Ions Type de document : texte imprimé Auteurs : Takashi Deguchi, Auteur ; Masakazu Iwamoto, Auteur Année de publication : 2011 Article en page(s) : pp. 4351–4358 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetics Mass transfer processes Résumé : Kinetic analysis including mass-transfer processes of the title reaction was carried out on the basis of the effects of the solution agitation rate, reaction time, and H2 and O2 partial pressures. The suggested equations were found to be in sufficient agreement with the experimental values. The reactions were then simulated to reveal the chemical engineering characteristics, as well as the process performance under practical reaction conditions. It follows that the reduction of the H2O2 destruction rate is highly desired and the mass-transfer coefficient of H2 (kLa) must be dramatically raised from 560 h−1, the value observed in the present experiments, for practical application of the technology. The effects of total pressure and other parameters are also discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102074z
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4351–4358[article] Kinetics and simulation including mass-transfer processes of direct H2O2 synthesis from H2 and O2 over Pd/C catalyst in water containing H+ and Br− Ions [texte imprimé] / Takashi Deguchi, Auteur ; Masakazu Iwamoto, Auteur . - 2011 . - pp. 4351–4358.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4351–4358
Mots-clés : Kinetics Mass transfer processes Résumé : Kinetic analysis including mass-transfer processes of the title reaction was carried out on the basis of the effects of the solution agitation rate, reaction time, and H2 and O2 partial pressures. The suggested equations were found to be in sufficient agreement with the experimental values. The reactions were then simulated to reveal the chemical engineering characteristics, as well as the process performance under practical reaction conditions. It follows that the reduction of the H2O2 destruction rate is highly desired and the mass-transfer coefficient of H2 (kLa) must be dramatically raised from 560 h−1, the value observed in the present experiments, for practical application of the technology. The effects of total pressure and other parameters are also discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102074z Exemplaires
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Titre : A new way to look at fischer−tropsch synthesis using flushing axperiments Type de document : texte imprimé Auteurs : Xiaojun Lu, Auteur ; Xiaowei Zhu, Auteur ; Diane Hildebrandt, Auteur Année de publication : 2011 Article en page(s) : pp. 4359–4365 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Fischer tropsch synthesis Résumé : When Fischer−Tropsch synthesis (FTS) reaction experiments were conducted in a gas−solid system with a TiO2-supported cobalt catalyst in a continuous stirred tank reactor (CSTR), we observed significant changes in the reaction rate and product selectivity at an early stage of time on stream (TOS) when all the reaction conditions were kept constant.(1) We designed flushing experiments with an inert gas that started when the FTS reaction had reached steady state. After the completion of flushing, the FTS reaction was resumed with syngas. We then compared the results of the FTS reaction rate and product selectivity both before and after flushing. The flushing experimental results suggested that the marked variations we observed were caused (either wholly or mainly) by liquid products deposited in the catalyst rather than by the change in the properties of the catalyst surface. The concentrations and the relative amount of the reactant in the flushed out stream were examined and the implications of the high H2/CO ratio for the reaction kinetics and product selectivity are discussed. On the basis of the dynamic concentrations of C1−C8 in the flushed outgas, we propose that reaction among the products takes place under moderate FTS reaction conditions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102095c
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4359–4365[article] A new way to look at fischer−tropsch synthesis using flushing axperiments [texte imprimé] / Xiaojun Lu, Auteur ; Xiaowei Zhu, Auteur ; Diane Hildebrandt, Auteur . - 2011 . - pp. 4359–4365.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4359–4365
Mots-clés : Fischer tropsch synthesis Résumé : When Fischer−Tropsch synthesis (FTS) reaction experiments were conducted in a gas−solid system with a TiO2-supported cobalt catalyst in a continuous stirred tank reactor (CSTR), we observed significant changes in the reaction rate and product selectivity at an early stage of time on stream (TOS) when all the reaction conditions were kept constant.(1) We designed flushing experiments with an inert gas that started when the FTS reaction had reached steady state. After the completion of flushing, the FTS reaction was resumed with syngas. We then compared the results of the FTS reaction rate and product selectivity both before and after flushing. The flushing experimental results suggested that the marked variations we observed were caused (either wholly or mainly) by liquid products deposited in the catalyst rather than by the change in the properties of the catalyst surface. The concentrations and the relative amount of the reactant in the flushed out stream were examined and the implications of the high H2/CO ratio for the reaction kinetics and product selectivity are discussed. On the basis of the dynamic concentrations of C1−C8 in the flushed outgas, we propose that reaction among the products takes place under moderate FTS reaction conditions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102095c Exemplaires
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Titre : Experimental study on the dynamic process of NO reduction in a precalciner Type de document : texte imprimé Auteurs : Lv Gang, Auteur ; Lu Jidong, Auteur ; Cai Lvqing, Auteur Année de publication : 2011 Article en page(s) : pp. 4366–4372 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Dynamic process Résumé : The dynamic processes of NO reduction by coals and char at different O2 concentrations have been investigated under the suspension conditions of a precalciner. The effects of cement raw meal, temperature, and O2 concentration on NO formation and reduction were studied. The results show that there are two stages in the NO reduction process in the presence of O2. The first stage is the early homogeneous NO reduction by volatiles, and the second is the heterogeneous oxidation of char N. The reduction of NO by coal with a higher volatiles content is more significant. At this stage, the quantities of NO reduction by Datong coal and Chenzhou coal were found to be 1.08 × 10−6 and 3.3 × 10−7 mol, respectively. In turn, the reduction capacity of Chenzhou coal is much larger than that of Chenzhou char (the quantity of NO reduction by Chenzhou char was 1 × 10−8 mol). Cement raw meal has positive effects on both NO reduction and NO formation. For the coal with the highest volatiles content (Datong), the total quantity of NO reduced by the coal increased from 1.08 × 10−6 to 1.52 × 10−6 mol when cement raw meal was present, whereas for Chenzhou char, the quantity increased only from 1 × 10−8 to 4 × 10−8 mol. For the two kinds of coals and the char, the effect of cement raw meal on NO formation was found to be relatively smaller. The temperature and O2 concentration can also affect the dynamic processes of NO conversion by coals and char, and the effect of temperature on NO reduction is more significant. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102118c
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4366–4372[article] Experimental study on the dynamic process of NO reduction in a precalciner [texte imprimé] / Lv Gang, Auteur ; Lu Jidong, Auteur ; Cai Lvqing, Auteur . - 2011 . - pp. 4366–4372.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4366–4372
Mots-clés : Dynamic process Résumé : The dynamic processes of NO reduction by coals and char at different O2 concentrations have been investigated under the suspension conditions of a precalciner. The effects of cement raw meal, temperature, and O2 concentration on NO formation and reduction were studied. The results show that there are two stages in the NO reduction process in the presence of O2. The first stage is the early homogeneous NO reduction by volatiles, and the second is the heterogeneous oxidation of char N. The reduction of NO by coal with a higher volatiles content is more significant. At this stage, the quantities of NO reduction by Datong coal and Chenzhou coal were found to be 1.08 × 10−6 and 3.3 × 10−7 mol, respectively. In turn, the reduction capacity of Chenzhou coal is much larger than that of Chenzhou char (the quantity of NO reduction by Chenzhou char was 1 × 10−8 mol). Cement raw meal has positive effects on both NO reduction and NO formation. For the coal with the highest volatiles content (Datong), the total quantity of NO reduced by the coal increased from 1.08 × 10−6 to 1.52 × 10−6 mol when cement raw meal was present, whereas for Chenzhou char, the quantity increased only from 1 × 10−8 to 4 × 10−8 mol. For the two kinds of coals and the char, the effect of cement raw meal on NO formation was found to be relatively smaller. The temperature and O2 concentration can also affect the dynamic processes of NO conversion by coals and char, and the effect of temperature on NO reduction is more significant. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102118c Exemplaires
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Titre : Effect of sulfur poisoning in high pressure catalytic partial oxidation of methane over Rh−Ce/Al2O3 catalyst Type de document : texte imprimé Auteurs : Jin Ki Hong, Auteur ; Lingzhi Zhang, Auteur ; Mark Thompson, Auteur Année de publication : 2011 Article en page(s) : pp. 4373–4380 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalytic partial Oxidation Methane Résumé : Short contact time catalytic partial oxidation (CPO) of methane has received increasing attention in industrial applications. Understanding of the catalytic system under high pressure and in the presence of sulfur represents a key challenge of this technology. This paper discusses CPO performance using a Rh−Ce catalyst supported on washcoat alumina foam under industrial relevant operating conditions (pressure up to 160 psig and different sulfur levels up to 16 ppm in methane). A long-term experimental run cycling between sulfur-free and sulfur injection conditions was conducted to examine the influence of sulfur on the catalyst. Sulfur effects were also evaluated under different sulfur levels and with different feed compositions. A dual zone reaction model was used to explain the effects of pressure, sulfur level, and the O/C ratio on CPO catalytic performance. Engineering challenges and requirements of the CPO process for industrial applications were discussed on the basis of recent advances in the understanding of CPO chemistry. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102159w
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4373–4380[article] Effect of sulfur poisoning in high pressure catalytic partial oxidation of methane over Rh−Ce/Al2O3 catalyst [texte imprimé] / Jin Ki Hong, Auteur ; Lingzhi Zhang, Auteur ; Mark Thompson, Auteur . - 2011 . - pp. 4373–4380.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4373–4380
Mots-clés : Catalytic partial Oxidation Methane Résumé : Short contact time catalytic partial oxidation (CPO) of methane has received increasing attention in industrial applications. Understanding of the catalytic system under high pressure and in the presence of sulfur represents a key challenge of this technology. This paper discusses CPO performance using a Rh−Ce catalyst supported on washcoat alumina foam under industrial relevant operating conditions (pressure up to 160 psig and different sulfur levels up to 16 ppm in methane). A long-term experimental run cycling between sulfur-free and sulfur injection conditions was conducted to examine the influence of sulfur on the catalyst. Sulfur effects were also evaluated under different sulfur levels and with different feed compositions. A dual zone reaction model was used to explain the effects of pressure, sulfur level, and the O/C ratio on CPO catalytic performance. Engineering challenges and requirements of the CPO process for industrial applications were discussed on the basis of recent advances in the understanding of CPO chemistry. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102159w Exemplaires
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Titre : Kinetic study of a novel active and stable catalyst for the water gas shift reaction Type de document : texte imprimé Auteurs : Carolina A. Cornaglia, Auteur ; John F. Munera, Auteur ; Eduardo A. Lombardo, Auteur Année de publication : 2011 Article en page(s) : pp. 4381–4389 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetic Gas Résumé : Two types of catalysts were synthesized and used in the Water Gas Shift Reaction (WGSR): Rh/La2O3 and Rh/La2O3-SiO2. The fresh and used catalysts were characterized through X-ray diffraction (XRD), laser raman spectroscopy (LRS), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The stability tests performed at 673 K (50 h time-on-stream) showed that the Rh/La2O3 slowly deactivated while Rh/La2O3-SiO2 exhibited high stability at least for 50 h on stream. The instrumental techniques offered some clues to explain the possible causes of deactivation of one formulation and the high stability of the other. The latter catalyst was more active than most high-temperature formulations reported in the literature. The kinetic measurements were made at atmospheric pressure and reaction temperatures between 598 and 723 K. The results obtained were fitted by a Langmuir−Hinshelwood mechanism assuming that the rate-determining step was the surface reaction of adsorbed CO and H2O. The parity plot showed a good correlation between the experimental and calculated reaction rates. The thermal parameters calculated with this model were all physically consistent. They were compared to kinetic, thermodynamic, and calculated data reported in the literature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102202u
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4381–4389[article] Kinetic study of a novel active and stable catalyst for the water gas shift reaction [texte imprimé] / Carolina A. Cornaglia, Auteur ; John F. Munera, Auteur ; Eduardo A. Lombardo, Auteur . - 2011 . - pp. 4381–4389.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4381–4389
Mots-clés : Kinetic Gas Résumé : Two types of catalysts were synthesized and used in the Water Gas Shift Reaction (WGSR): Rh/La2O3 and Rh/La2O3-SiO2. The fresh and used catalysts were characterized through X-ray diffraction (XRD), laser raman spectroscopy (LRS), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The stability tests performed at 673 K (50 h time-on-stream) showed that the Rh/La2O3 slowly deactivated while Rh/La2O3-SiO2 exhibited high stability at least for 50 h on stream. The instrumental techniques offered some clues to explain the possible causes of deactivation of one formulation and the high stability of the other. The latter catalyst was more active than most high-temperature formulations reported in the literature. The kinetic measurements were made at atmospheric pressure and reaction temperatures between 598 and 723 K. The results obtained were fitted by a Langmuir−Hinshelwood mechanism assuming that the rate-determining step was the surface reaction of adsorbed CO and H2O. The parity plot showed a good correlation between the experimental and calculated reaction rates. The thermal parameters calculated with this model were all physically consistent. They were compared to kinetic, thermodynamic, and calculated data reported in the literature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102202u Exemplaires
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Titre : Catalytic properties of Cu/13X zeolite based catalyst in catalytic wet peroxide oxidation of phenol Type de document : texte imprimé Auteurs : Karolina Maduna Valkaj, Auteur ; Andrea Katovic, Auteur ; Stanka Zrncevic, Auteur Année de publication : 2011 Article en page(s) : pp. 4390–4397 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Zeolite Catalytic Oxidation Résumé : Copper bearing 13X zeolite was prepared from commercial 13X zeolite via ion-exchange with copper acetate solutions. After the incorporation of copper, Cu/13X catalyst was exposed to post synthesis thermal treatment at different temperatures. The prepared catalysts were characterized by XRD and FTIR, while the adsorption techniques were used for the measurement of the specific surface area and pore volume. The catalytic tests were carried out in a stainless steel Parr reactor in batch operation mode at atmospheric pressure in temperature range from 333 to 353 K. Influence of postsynthesis thermal treatment and reaction temperature on activity and stability of prepared catalysts in the catalytic wet oxidation process with hydrogen peroxide as oxidant was investigated. The experimental results showed that total degradation of phenol can be achieved under mild operating conditions at temperatures bellow 353 K. All catalysts exhibited higher activity in terms of hydrogen peroxide and phenol abatement with the increasing temperature of the reaction. The postsynthesis thermal treatment resulted in more stable catalyst with respect to stability of both catalysts’ active metal component (copper) and support, while the activity of catalysts in terms of TOC conversion remained unaltered. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102223g
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4390–4397[article] Catalytic properties of Cu/13X zeolite based catalyst in catalytic wet peroxide oxidation of phenol [texte imprimé] / Karolina Maduna Valkaj, Auteur ; Andrea Katovic, Auteur ; Stanka Zrncevic, Auteur . - 2011 . - pp. 4390–4397.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4390–4397
Mots-clés : Zeolite Catalytic Oxidation Résumé : Copper bearing 13X zeolite was prepared from commercial 13X zeolite via ion-exchange with copper acetate solutions. After the incorporation of copper, Cu/13X catalyst was exposed to post synthesis thermal treatment at different temperatures. The prepared catalysts were characterized by XRD and FTIR, while the adsorption techniques were used for the measurement of the specific surface area and pore volume. The catalytic tests were carried out in a stainless steel Parr reactor in batch operation mode at atmospheric pressure in temperature range from 333 to 353 K. Influence of postsynthesis thermal treatment and reaction temperature on activity and stability of prepared catalysts in the catalytic wet oxidation process with hydrogen peroxide as oxidant was investigated. The experimental results showed that total degradation of phenol can be achieved under mild operating conditions at temperatures bellow 353 K. All catalysts exhibited higher activity in terms of hydrogen peroxide and phenol abatement with the increasing temperature of the reaction. The postsynthesis thermal treatment resulted in more stable catalyst with respect to stability of both catalysts’ active metal component (copper) and support, while the activity of catalysts in terms of TOC conversion remained unaltered. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102223g Exemplaires
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Titre : SOx oxidation and adsorption by CeO2/MgO : synergistic effect between CeO2 and MgO in the fluid catalytic cracking process Type de document : texte imprimé Auteurs : Lei Jiang, Auteur ; Min Wei, Auteur ; Xiangyu Xu, Auteur Année de publication : 2011 Article en page(s) : pp. 4398–4404 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : SOx Oxidation Fluid catalytic Résumé : The sulfur-transfer catalyst plays an important role in the fluid catalytic cracking (FCC) process through which the sulfur oxides (SOx) are removed from flue gas. This work reports the synergistic effect between CeO2 and MgO on the SOx oxidation and adsorption in the FCC process. The CeO2 acts as the oxidation promoter, while MgO is the active phase for SOx adsorption. The influence of crystal size on the synergistic effect between CeO2 and MgO on the SOx oxidation and adsorption was investigated. It was observed that the initial apparent SOx pick-up rate decreases with the increase in the CeO2 crystal size, while the maximum SOx oxidation and adsorption capacity decreases with the increase in the MgO crystal size. Therefore, this work provides a detailed understanding of the synergistic effect between CeO2 and MgO for the SOx pick-up, which is crucial for the rational design and preparation of the sulfur-transfer catalysts. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102243y
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4398–4404[article] SOx oxidation and adsorption by CeO2/MgO : synergistic effect between CeO2 and MgO in the fluid catalytic cracking process [texte imprimé] / Lei Jiang, Auteur ; Min Wei, Auteur ; Xiangyu Xu, Auteur . - 2011 . - pp. 4398–4404.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4398–4404
Mots-clés : SOx Oxidation Fluid catalytic Résumé : The sulfur-transfer catalyst plays an important role in the fluid catalytic cracking (FCC) process through which the sulfur oxides (SOx) are removed from flue gas. This work reports the synergistic effect between CeO2 and MgO on the SOx oxidation and adsorption in the FCC process. The CeO2 acts as the oxidation promoter, while MgO is the active phase for SOx adsorption. The influence of crystal size on the synergistic effect between CeO2 and MgO on the SOx oxidation and adsorption was investigated. It was observed that the initial apparent SOx pick-up rate decreases with the increase in the CeO2 crystal size, while the maximum SOx oxidation and adsorption capacity decreases with the increase in the MgO crystal size. Therefore, this work provides a detailed understanding of the synergistic effect between CeO2 and MgO for the SOx pick-up, which is crucial for the rational design and preparation of the sulfur-transfer catalysts. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102243y Exemplaires
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Titre : Fabrication and catalytic properties of palladium nanoparticles deposited on a silanized asymmetric ceramic support Type de document : texte imprimé Auteurs : Rizhi Chen, Auteur ; Yuanguo Jiang, Auteur ; Weihong Xing, Auteur Année de publication : 2011 Article en page(s) : pp. 4405–4411 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalytic properties Asymmetric ceramic Résumé : We developed an improved fabrication technique for the deposition of palladium nanoparticles on a ceramic membrane support in which the support surface was silanized with amino-functional silane. In the present work, the ceramic membrane support was used for catalyst immobilization only. The as-fabricated Pd-loaded ceramic membrane support was extensively characterized by ICP emission spectroscopy, XRD, FESEM, EDS, XPS, HRTEM, and TPR, and its catalytic properties were tested in the liquid-phase hydrogenation of p-nitrophenol to p-aminophenol. A comparative study was also made with palladium nanoparticles deposited on the ceramic membrane support without silanization. Higher catalytic activity and stability were observed for the palladium nanoparticles deposited on the surface-silanized ceramic membrane support. The reason proposed for the higher catalytic activity is the higher dispersion of the palladium nanoparticles. The palladium nanoparticles were loaded onto the surface-silanized ceramic membrane support with chemical bonds; thus, it was not easy for the palladium nanoparticles to detach from the silanized membrane support, and a superior catalytic stability could be obtained. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1022578
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4405–4411[article] Fabrication and catalytic properties of palladium nanoparticles deposited on a silanized asymmetric ceramic support [texte imprimé] / Rizhi Chen, Auteur ; Yuanguo Jiang, Auteur ; Weihong Xing, Auteur . - 2011 . - pp. 4405–4411.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4405–4411
Mots-clés : Catalytic properties Asymmetric ceramic Résumé : We developed an improved fabrication technique for the deposition of palladium nanoparticles on a ceramic membrane support in which the support surface was silanized with amino-functional silane. In the present work, the ceramic membrane support was used for catalyst immobilization only. The as-fabricated Pd-loaded ceramic membrane support was extensively characterized by ICP emission spectroscopy, XRD, FESEM, EDS, XPS, HRTEM, and TPR, and its catalytic properties were tested in the liquid-phase hydrogenation of p-nitrophenol to p-aminophenol. A comparative study was also made with palladium nanoparticles deposited on the ceramic membrane support without silanization. Higher catalytic activity and stability were observed for the palladium nanoparticles deposited on the surface-silanized ceramic membrane support. The reason proposed for the higher catalytic activity is the higher dispersion of the palladium nanoparticles. The palladium nanoparticles were loaded onto the surface-silanized ceramic membrane support with chemical bonds; thus, it was not easy for the palladium nanoparticles to detach from the silanized membrane support, and a superior catalytic stability could be obtained. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1022578 Exemplaires
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Titre : Pyrolysis of ethanol : gas and soot products formed Type de document : texte imprimé Auteurs : Claudia Esarte, Auteur ; Maria Peg, Auteur ; Maria P. Ruiz, Auteur Année de publication : 2011 Article en page(s) : pp. 4412–4419 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ethanol Gas Résumé : Ethanol may be used in diesel−ethanol mixtures in order to decrease soot emissions. Therefore, it is important to evaluate the contribution of ethanol to soot formation. The influence of the temperature on the pyrolysis of ethanol under sooting conditions has been studied. Pyrolysis experiments were carried out in a quartz reactor in the 700−1200 °C temperature range, for an inlet C2H5OH concentration of 50 000 ppm and a gas residence time in seconds of 1706/(T/K) . The concentrations of the gases analyzed in the experiments are shown in this work together with simulations carried out with a literature kinetic model. Theoretical and experimental results present, generally, a good agreement in spite of the model not taking into account the soot formation. Under the studied conditions, soot formation has been observed above 1050 °C. With the soot samples obtained, a study of their reactivity toward O2 and NO has been carried out, and several characterization techniques, such as elemental analysis, Brunauer−Emmett−Teller (BET) surface area, transmission electron microscopy, and X-ray diffraction have been used to study the structural properties of the collected soot samples and relate them to their reactivity. It has been observed that the soot samples formed at higher temperatures exhibit a lower reactivity toward O2 and NO, and the characterization analyses support these results. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1022628
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4412–4419[article] Pyrolysis of ethanol : gas and soot products formed [texte imprimé] / Claudia Esarte, Auteur ; Maria Peg, Auteur ; Maria P. Ruiz, Auteur . - 2011 . - pp. 4412–4419.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4412–4419
Mots-clés : Ethanol Gas Résumé : Ethanol may be used in diesel−ethanol mixtures in order to decrease soot emissions. Therefore, it is important to evaluate the contribution of ethanol to soot formation. The influence of the temperature on the pyrolysis of ethanol under sooting conditions has been studied. Pyrolysis experiments were carried out in a quartz reactor in the 700−1200 °C temperature range, for an inlet C2H5OH concentration of 50 000 ppm and a gas residence time in seconds of 1706/(T/K) . The concentrations of the gases analyzed in the experiments are shown in this work together with simulations carried out with a literature kinetic model. Theoretical and experimental results present, generally, a good agreement in spite of the model not taking into account the soot formation. Under the studied conditions, soot formation has been observed above 1050 °C. With the soot samples obtained, a study of their reactivity toward O2 and NO has been carried out, and several characterization techniques, such as elemental analysis, Brunauer−Emmett−Teller (BET) surface area, transmission electron microscopy, and X-ray diffraction have been used to study the structural properties of the collected soot samples and relate them to their reactivity. It has been observed that the soot samples formed at higher temperatures exhibit a lower reactivity toward O2 and NO, and the characterization analyses support these results. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1022628 Exemplaires
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Titre : Production of C3 hydrocarbons from biomass via hydrothermal carboxylate reforming Type de document : texte imprimé Auteurs : Curt R. Fischer, Auteur ; Andrew A. Peterson, Auteur ; Jefferson W. Tester, Auteur Année de publication : 2011 Article en page(s) : pp. 4420–4424 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Biomass Hydrothermal Carboxylate Résumé : We demonstrate a route for the production of C3 hydrocarbons from renewable biomass by the hydrothermal conversion of well-known fermentation end-products. Specifically, the major commercial C3 hydrocarbons, propane and propylene, can be obtained from butyric acid and 3-hydroxybutyrate (3HB) in substantial yields and industrially relevant productivities by hydrothermal decarboxylation. Butyric acid decarboxylates in supercritical water to give propane as the major product at 454 °C and 25 MPa. 3HB undergoes joint dehydration and decarboxylation in subcritical water to yield propylene at 371 °C and 25 MPa with yields of up to 48 mol %. Although catalysts may be found that increase yields and selectivities, these processes were demonstrated without any added heterogeneous catalysts, and have the further advantage of requiring no external H2 source. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1023386
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4420–4424[article] Production of C3 hydrocarbons from biomass via hydrothermal carboxylate reforming [texte imprimé] / Curt R. Fischer, Auteur ; Andrew A. Peterson, Auteur ; Jefferson W. Tester, Auteur . - 2011 . - pp. 4420–4424.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4420–4424
Mots-clés : Biomass Hydrothermal Carboxylate Résumé : We demonstrate a route for the production of C3 hydrocarbons from renewable biomass by the hydrothermal conversion of well-known fermentation end-products. Specifically, the major commercial C3 hydrocarbons, propane and propylene, can be obtained from butyric acid and 3-hydroxybutyrate (3HB) in substantial yields and industrially relevant productivities by hydrothermal decarboxylation. Butyric acid decarboxylates in supercritical water to give propane as the major product at 454 °C and 25 MPa. 3HB undergoes joint dehydration and decarboxylation in subcritical water to yield propylene at 371 °C and 25 MPa with yields of up to 48 mol %. Although catalysts may be found that increase yields and selectivities, these processes were demonstrated without any added heterogeneous catalysts, and have the further advantage of requiring no external H2 source. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1023386 Exemplaires
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Titre : Experimental investigation on the kinetics of NO complex absorption through FeIIEDTA solvent in a double-stirred reactor Type de document : texte imprimé Auteurs : Qian Du, Auteur ; Haoyang Zhao, Auteur ; Leiling Ming, Auteur Année de publication : 2011 Article en page(s) : pp. 4425–4431 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetics Résumé : NO emission is a significant source of pollutant from coal combustion. With the establishment of industry flue gas emission standards, removal of NO has been attracting attention and research globally. In this paper, the denitration process through the use of a FeII complex solvent has been studied based on the approach of the wet desulfurization method. The kinetic parameters of the chemical reaction for NO absorption by FeII complex have also been deduced to provide theoretical consideration for the feasibility of this process. It is demonstrated that FeIIEDTA adsorbs NO efficiently under the conditions investigated, achieving the maximum NO reduction efficiency at a neutral pH value at 50 °C. The inlet O2 content in flue gas is a crucial factor affecting the performance of FeII complex, the increment in which leads to the oxidation of FeII into FeIII and hence reduces the absorption capability of the sorbent. The coexistence of SO2 and NO in flue gas decreases the NO removal efficiency by being preferentially adsorbed by the sorbent. However, with the increasing content of SO2 in flue gas, the solvent’s capability in absorbing NO is recovered to its original level. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102501h
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4425–4431[article] Experimental investigation on the kinetics of NO complex absorption through FeIIEDTA solvent in a double-stirred reactor [texte imprimé] / Qian Du, Auteur ; Haoyang Zhao, Auteur ; Leiling Ming, Auteur . - 2011 . - pp. 4425–4431.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4425–4431
Mots-clés : Kinetics Résumé : NO emission is a significant source of pollutant from coal combustion. With the establishment of industry flue gas emission standards, removal of NO has been attracting attention and research globally. In this paper, the denitration process through the use of a FeII complex solvent has been studied based on the approach of the wet desulfurization method. The kinetic parameters of the chemical reaction for NO absorption by FeII complex have also been deduced to provide theoretical consideration for the feasibility of this process. It is demonstrated that FeIIEDTA adsorbs NO efficiently under the conditions investigated, achieving the maximum NO reduction efficiency at a neutral pH value at 50 °C. The inlet O2 content in flue gas is a crucial factor affecting the performance of FeII complex, the increment in which leads to the oxidation of FeII into FeIII and hence reduces the absorption capability of the sorbent. The coexistence of SO2 and NO in flue gas decreases the NO removal efficiency by being preferentially adsorbed by the sorbent. However, with the increasing content of SO2 in flue gas, the solvent’s capability in absorbing NO is recovered to its original level. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102501h Exemplaires
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Titre : Studies on stress relaxation and thermomechanical properties of poly(acrylonitrile-butadiene-styrene) modified epoxy−amine systems Type de document : texte imprimé Auteurs : Jyotishkumar P, Auteur ; Jurgen Pionteck, Auteur ; Rudiger Hassler, Auteur Année de publication : 2011 Article en page(s) : pp. 4432–4440 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Thermomechanical properties Résumé : Epoxy networks based on diglycidyl ether of bisphenol A cured with diamino diphenyl sulfone and modified with poly(acrylonitrile-butadiene-styrene) (ABS) were prepared according to two different cure schedules, one with a single step curing and the other with two step curing. The samples were carefully analyzed by thermomechanical analysis (TMA) to understand the physical aging phenomenon. The TMA runs on samples with single curing step are strained and show “bumps” in the expansion traces indicating that internal stress relaxation takes place during heating. On the other hand, the samples prepared by two-step curing were not strained and hence no bumps occurred. The ABS modified epoxy blends were further characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), mechanical tests using a universal testing machine, and field emission scanning electron microscopy (FESEM). The FTIR spectroscopy study confirms that the epoxy/amine reaction was complete, irrespective of the cure schedule used. TEM micrographs reveals heterogeneous morphology for all the blends studied. DSC and TGA were employed to evaluate the thermal stability of epoxy/ABS blends. The mechanical properties of both strained and unstrained samples were investigated in detail and are correlated to the blend morphologies. The result shows that the mechanical and morphological properties are affected by blending with the thermoplastic but not with the cure schedule used. The addition of low ABS amounts (≤6.9 wt %) in the epoxy resin resulted in epoxy matrix/ABS particle morphologies leading to more than 100% increase in tensile toughness compared to neat cross-linked epoxy. FESEM micrographs of fractured surfaces proved fracture mechanisms such as nanocavitation, crack path deflection, crack pinning, ductile tearing of the thermoplastic, and local plastic deformation of the matrix. In contrast, when cocontinuous morphologies are formed at higher ABS loadings the mechanical properties are much lower than those formed for the neat epoxy system. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1016915
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4432–4440[article] Studies on stress relaxation and thermomechanical properties of poly(acrylonitrile-butadiene-styrene) modified epoxy−amine systems [texte imprimé] / Jyotishkumar P, Auteur ; Jurgen Pionteck, Auteur ; Rudiger Hassler, Auteur . - 2011 . - pp. 4432–4440.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4432–4440
Mots-clés : Thermomechanical properties Résumé : Epoxy networks based on diglycidyl ether of bisphenol A cured with diamino diphenyl sulfone and modified with poly(acrylonitrile-butadiene-styrene) (ABS) were prepared according to two different cure schedules, one with a single step curing and the other with two step curing. The samples were carefully analyzed by thermomechanical analysis (TMA) to understand the physical aging phenomenon. The TMA runs on samples with single curing step are strained and show “bumps” in the expansion traces indicating that internal stress relaxation takes place during heating. On the other hand, the samples prepared by two-step curing were not strained and hence no bumps occurred. The ABS modified epoxy blends were further characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), mechanical tests using a universal testing machine, and field emission scanning electron microscopy (FESEM). The FTIR spectroscopy study confirms that the epoxy/amine reaction was complete, irrespective of the cure schedule used. TEM micrographs reveals heterogeneous morphology for all the blends studied. DSC and TGA were employed to evaluate the thermal stability of epoxy/ABS blends. The mechanical properties of both strained and unstrained samples were investigated in detail and are correlated to the blend morphologies. The result shows that the mechanical and morphological properties are affected by blending with the thermoplastic but not with the cure schedule used. The addition of low ABS amounts (≤6.9 wt %) in the epoxy resin resulted in epoxy matrix/ABS particle morphologies leading to more than 100% increase in tensile toughness compared to neat cross-linked epoxy. FESEM micrographs of fractured surfaces proved fracture mechanisms such as nanocavitation, crack path deflection, crack pinning, ductile tearing of the thermoplastic, and local plastic deformation of the matrix. In contrast, when cocontinuous morphologies are formed at higher ABS loadings the mechanical properties are much lower than those formed for the neat epoxy system. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1016915 Exemplaires
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Titre : Fabrication of superhydrophobic cotton fabrics with UV protection based on CeO2 particles Type de document : texte imprimé Auteurs : Wei Duan, Auteur ; Anjian Xie, Auteur ; Yuhua Shen, Auteur Année de publication : 2011 Article en page(s) : pp. 4441–4445 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Superhydrophobic cotton UV protection Résumé : Water repellency and ultraviolet (UV) protection are desirable properties for textiles. In this paper, the cotton fabrics were first treated with CeO2 sol and then modified with a layer of dodecafluoroheptyl-propyl-trimethoxylsilane (DFTMS). The as-obtained cotton sample was characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and Fourier transformation infrared spectroscopy (FTIR), water contact angle measurement, and UV−vis spectrophotometry. The modified cotton surface not only exhibited robust superhydrophobicity with a high contact angle of 158° and low roll-off angle of 14° for 5-μL water droplets, but also rendered excellent protection against UV radiation because of incorporation of CeO2 particles. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101924v
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4441–4445[article] Fabrication of superhydrophobic cotton fabrics with UV protection based on CeO2 particles [texte imprimé] / Wei Duan, Auteur ; Anjian Xie, Auteur ; Yuhua Shen, Auteur . - 2011 . - pp. 4441–4445.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4441–4445
Mots-clés : Superhydrophobic cotton UV protection Résumé : Water repellency and ultraviolet (UV) protection are desirable properties for textiles. In this paper, the cotton fabrics were first treated with CeO2 sol and then modified with a layer of dodecafluoroheptyl-propyl-trimethoxylsilane (DFTMS). The as-obtained cotton sample was characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and Fourier transformation infrared spectroscopy (FTIR), water contact angle measurement, and UV−vis spectrophotometry. The modified cotton surface not only exhibited robust superhydrophobicity with a high contact angle of 158° and low roll-off angle of 14° for 5-μL water droplets, but also rendered excellent protection against UV radiation because of incorporation of CeO2 particles. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101924v Exemplaires
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Titre : Online Detection of Moisture in Heatset Printing : The Role of Substrate Structure during Liquid Transfer Type de document : texte imprimé Auteurs : Carl-Mikael Tag, Auteur ; Maunu Toiviainen, Auteur ; Mikko Juuti, Auteur Année de publication : 2011 Article en page(s) : pp.4446–4457 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Liquid transfer Résumé : Liquid transfer in a heatset printing process to coated papers has been evaluated online. The porous coatings, applied in various combinations of single coating onto a fine paper substrate, together with selective particle size distributions containing calcium carbonate pigments were calendered under different conditions to establish a range of porosities and pore structures while keeping the formulation and hence the surface chemistry constant. The transfer of fountain solution to the papers was analyzed from unprinted areas (nonimage) at six different positions along the printing line, namely, between each printing unit and after the dryer section, using near-infrared absorption reflectometry. In this way, real-time analysis of the amount of fountain solution (defined as water content) transferred to the paper per printing unit as a function of physical paper surface characteristics has been achieved. The role of printing speed and fountain solution dosage level on water uptake by the various coated paper substrates has been investigated. It was concluded that the higher the speed, firstly, there is less compression of the surface roughness and, secondly, less time for the liquid to respond with respect to capillary forces, resulting in less liquid transfer. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1022157
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp.4446–4457[article] Online Detection of Moisture in Heatset Printing : The Role of Substrate Structure during Liquid Transfer [texte imprimé] / Carl-Mikael Tag, Auteur ; Maunu Toiviainen, Auteur ; Mikko Juuti, Auteur . - 2011 . - pp.4446–4457.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp.4446–4457
Mots-clés : Liquid transfer Résumé : Liquid transfer in a heatset printing process to coated papers has been evaluated online. The porous coatings, applied in various combinations of single coating onto a fine paper substrate, together with selective particle size distributions containing calcium carbonate pigments were calendered under different conditions to establish a range of porosities and pore structures while keeping the formulation and hence the surface chemistry constant. The transfer of fountain solution to the papers was analyzed from unprinted areas (nonimage) at six different positions along the printing line, namely, between each printing unit and after the dryer section, using near-infrared absorption reflectometry. In this way, real-time analysis of the amount of fountain solution (defined as water content) transferred to the paper per printing unit as a function of physical paper surface characteristics has been achieved. The role of printing speed and fountain solution dosage level on water uptake by the various coated paper substrates has been investigated. It was concluded that the higher the speed, firstly, there is less compression of the surface roughness and, secondly, less time for the liquid to respond with respect to capillary forces, resulting in less liquid transfer. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1022157 Exemplaires
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Titre : Low-temperature wet-cross-linking of silk with citric acid Type de document : texte imprimé Auteurs : Narendra Reddy, Auteur ; Karlin Warner, Auteur ; Yiqi Yang, Auteur Année de publication : 2011 Article en page(s) : pp. 4458–4463 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Silk Citric acid Résumé : We report the development of a novel method of improving the wet wrinkle recovery of silk fabrics without affecting the whiteness or the tensile properties of the cross-linked fabrics. Previous attempts on cross-linking silk with poly(carboxylic acids) have been done in the dry state at high temperatures (150−175 °C) in the presence of the toxic catalyst, sodium hypophosphite, with decrease in the whiteness and tensile properties of the cross-linked fabrics. In this research, citric acid (CA) was used to cross-link silk in the wet state at low temperatures using weak acidic to neutral pH as catalyst. The effect of cross-linking conditions on the wrinkle recovery, whiteness index and yarn tensile and fabric tear strength were studied. The durability of the cross-linking to laundering was also examined. The new method of cross-linking improves the wet wrinkle recovery of the silk fabrics by about 32% compared to the noncross-linked fabric without affecting the whiteness or the tensile properties of the fabrics. The improvement in the functional properties of silk was stable to multiple launderings. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102226f
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4458–4463[article] Low-temperature wet-cross-linking of silk with citric acid [texte imprimé] / Narendra Reddy, Auteur ; Karlin Warner, Auteur ; Yiqi Yang, Auteur . - 2011 . - pp. 4458–4463.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4458–4463
Mots-clés : Silk Citric acid Résumé : We report the development of a novel method of improving the wet wrinkle recovery of silk fabrics without affecting the whiteness or the tensile properties of the cross-linked fabrics. Previous attempts on cross-linking silk with poly(carboxylic acids) have been done in the dry state at high temperatures (150−175 °C) in the presence of the toxic catalyst, sodium hypophosphite, with decrease in the whiteness and tensile properties of the cross-linked fabrics. In this research, citric acid (CA) was used to cross-link silk in the wet state at low temperatures using weak acidic to neutral pH as catalyst. The effect of cross-linking conditions on the wrinkle recovery, whiteness index and yarn tensile and fabric tear strength were studied. The durability of the cross-linking to laundering was also examined. The new method of cross-linking improves the wet wrinkle recovery of the silk fabrics by about 32% compared to the noncross-linked fabric without affecting the whiteness or the tensile properties of the fabrics. The improvement in the functional properties of silk was stable to multiple launderings. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102226f Exemplaires
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Titre : Carbonation and active-component-distribution behaviors of several potassium-based sorbents Type de document : texte imprimé Auteurs : Chuanwen Zhao, Auteur ; Xiaoping Chen, Auteur ; Changsui Zhao, Auteur Année de publication : 2011 Article en page(s) : pp. 4464–4470 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Carbonation Potassium Sorbents Résumé : To investigate active-component-distribution and carbonation behaviors, potassium-based sorbents were prepared by impregnation of K2CO3, K2CO3·1.5H2O, and KHCO3 on supports such as activated carbon (AC) and Al2O3. The CO2 capture capacity is significantly increased for K2CO3 and K2CO3 dehydrated from K2CO3·1.5H2O after they have been loaded on AC and Al2O3. For the sorbents with AC as their support, the active components keep their original phase in the impregnation process. Under an atmosphere of CO2 and H2O, the hydration reaction occurs first, and then KHCO3 is produced rapidly. The active components are held in macropore spaces without blocking micropores, and the rest is nonuniformly distributed on the surface of AC in the form of large aggregates. For the sorbents with Al2O3 as their support, all of the active components change into K2CO3 during the impregnation process. Under the same reaction atmosphere, K2CO3·1.5H2O is not produced. H2O is adsorbed at first, and then CO2 reacts with the adsorbed H2O and K2CO3 to produce KHCO3. Most of the active components are distributed in the mesopores and macropores of the support, and the rest is uniformly distributed on the surface of Al2O3 in the form of many small ag gregates. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200153c
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4464–4470[article] Carbonation and active-component-distribution behaviors of several potassium-based sorbents [texte imprimé] / Chuanwen Zhao, Auteur ; Xiaoping Chen, Auteur ; Changsui Zhao, Auteur . - 2011 . - pp. 4464–4470.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4464–4470
Mots-clés : Carbonation Potassium Sorbents Résumé : To investigate active-component-distribution and carbonation behaviors, potassium-based sorbents were prepared by impregnation of K2CO3, K2CO3·1.5H2O, and KHCO3 on supports such as activated carbon (AC) and Al2O3. The CO2 capture capacity is significantly increased for K2CO3 and K2CO3 dehydrated from K2CO3·1.5H2O after they have been loaded on AC and Al2O3. For the sorbents with AC as their support, the active components keep their original phase in the impregnation process. Under an atmosphere of CO2 and H2O, the hydration reaction occurs first, and then KHCO3 is produced rapidly. The active components are held in macropore spaces without blocking micropores, and the rest is nonuniformly distributed on the surface of AC in the form of large aggregates. For the sorbents with Al2O3 as their support, all of the active components change into K2CO3 during the impregnation process. Under the same reaction atmosphere, K2CO3·1.5H2O is not produced. H2O is adsorbed at first, and then CO2 reacts with the adsorbed H2O and K2CO3 to produce KHCO3. Most of the active components are distributed in the mesopores and macropores of the support, and the rest is uniformly distributed on the surface of Al2O3 in the form of many small ag gregates. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200153c Exemplaires
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Titre : Nonisothermal and isothermal cold crystallization behaviors of biodegradable poly(p-dioxanone) Type de document : texte imprimé Auteurs : Jian-Bing Zeng, Auteur ; Madhusudhan Srinivansan, Auteur ; Shao-Long Li, Auteur Année de publication : 2011 Article en page(s) : pp. 4471–4477 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nonisothermal Isothermal Crystallization Biodegradable Résumé : Nonisothermal and isothermal cold crystallization behaviors of poly(p-dioxanone) (PPDO) were investigated by differential scanning calorimetry (DSC). There were two crystallization exotherms—a major exotherm between 25 °C and 50 °C and a minor one almost unchanged at 77 °C with various heating rates—in the heating scans of PPDO during nonisothermal cold crystallization. Temperature-modulated differential scanning calorimetry (TMDSC) revealed the major crystallization exotherm in the low-temperature range to be the real cold crystallization peak, and the minor one in the high-temperature range to be the melt-recrystallization peak of crystals with lower thermal stability. Several methods, including the Avrami, Tobin, and Ozawa equations, were employed to analyze the nonisothermal cold crystallization kinetics of PPDO. The efficiencies of the Avrami and Tobin methods were compared, and the results suggest that the Avrami equation is more suitable for describing nonisothermal cold crystallization kinetics of PPDO. The activation energy for nonisothermal cold crystallization of PPDO was calculated to be 35.27 kJ/mol, using the Kissinger method. In addition, the Avrami equation was also used to describe the isothermal cold crystallization kinetics of PPDO. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102299y
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4471–4477[article] Nonisothermal and isothermal cold crystallization behaviors of biodegradable poly(p-dioxanone) [texte imprimé] / Jian-Bing Zeng, Auteur ; Madhusudhan Srinivansan, Auteur ; Shao-Long Li, Auteur . - 2011 . - pp. 4471–4477.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4471–4477
Mots-clés : Nonisothermal Isothermal Crystallization Biodegradable Résumé : Nonisothermal and isothermal cold crystallization behaviors of poly(p-dioxanone) (PPDO) were investigated by differential scanning calorimetry (DSC). There were two crystallization exotherms—a major exotherm between 25 °C and 50 °C and a minor one almost unchanged at 77 °C with various heating rates—in the heating scans of PPDO during nonisothermal cold crystallization. Temperature-modulated differential scanning calorimetry (TMDSC) revealed the major crystallization exotherm in the low-temperature range to be the real cold crystallization peak, and the minor one in the high-temperature range to be the melt-recrystallization peak of crystals with lower thermal stability. Several methods, including the Avrami, Tobin, and Ozawa equations, were employed to analyze the nonisothermal cold crystallization kinetics of PPDO. The efficiencies of the Avrami and Tobin methods were compared, and the results suggest that the Avrami equation is more suitable for describing nonisothermal cold crystallization kinetics of PPDO. The activation energy for nonisothermal cold crystallization of PPDO was calculated to be 35.27 kJ/mol, using the Kissinger method. In addition, the Avrami equation was also used to describe the isothermal cold crystallization kinetics of PPDO. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102299y Exemplaires
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Titre : In situ fabrication of surface modified lead monoxide nanopowder and its HDPE nanocomposite Type de document : texte imprimé Auteurs : Young Rang Uhm, Auteur ; Jaewoo Kim, Auteur ; Sol Lee, Auteur Année de publication : 2011 Article en page(s) : pp. 4478–4483 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nanopowder Nanocomposite Résumé : Low density polyethylene (LDPE) coated lead monoxide (PbO) nanopowder was fabricated by using in situ high energy wet ball milling. Degrees of pulverization of wet milled PbO together with LDPE and cyclohexane were analyzed by means of PSA and SEM. PbO powder could be pulverized to 100 nm for 1 h milling while the surfaces of the powder particles were modified with LDPE simultaneously. Surface modification by elemental interdiffusion of PbO and carbon on the particulate boundary was confirmed by TEM/EDX. High density polyethylene (HDPE) nanocomposites were also prepared by dispersing micro- and nano-PbO/LDPE powders using a polymer melting mixer. Dispersion and adhesion of PbO/LDPE nanoparticles in or with the polymer matrix were homogeneous and strong respectively according to the SEM images as well as the FTIR spectra, while the HDPE nanocomposites show higher mechanical properties than those for micro-PbO powder dispersed ones. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102300x
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4478–4483[article] In situ fabrication of surface modified lead monoxide nanopowder and its HDPE nanocomposite [texte imprimé] / Young Rang Uhm, Auteur ; Jaewoo Kim, Auteur ; Sol Lee, Auteur . - 2011 . - pp. 4478–4483.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4478–4483
Mots-clés : Nanopowder Nanocomposite Résumé : Low density polyethylene (LDPE) coated lead monoxide (PbO) nanopowder was fabricated by using in situ high energy wet ball milling. Degrees of pulverization of wet milled PbO together with LDPE and cyclohexane were analyzed by means of PSA and SEM. PbO powder could be pulverized to 100 nm for 1 h milling while the surfaces of the powder particles were modified with LDPE simultaneously. Surface modification by elemental interdiffusion of PbO and carbon on the particulate boundary was confirmed by TEM/EDX. High density polyethylene (HDPE) nanocomposites were also prepared by dispersing micro- and nano-PbO/LDPE powders using a polymer melting mixer. Dispersion and adhesion of PbO/LDPE nanoparticles in or with the polymer matrix were homogeneous and strong respectively according to the SEM images as well as the FTIR spectra, while the HDPE nanocomposites show higher mechanical properties than those for micro-PbO powder dispersed ones. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102300x Exemplaires
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Titre : Coalescence of bubbles and stability of foams in brij surfactant systems Type de document : texte imprimé Auteurs : Sayantan Samanta, Auteur ; Pallab Ghosh, Auteur Année de publication : 2011 Article en page(s) : pp. 4484–4493 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Coalescence air bubbles Aqueous solutions polyoxyethylene Résumé : This work presents coalescence of air bubbles and stability of foams in aqueous solutions of polyoxyethylene (4) lauryl ether (Brij 30), polyoxyethylene (23) lauryl ether (Brij 35), and polyoxyethylene (20) oleyl ether (Brij 98). Adsorption of these surfactants at the air−water interface was also studied. The surface tension profiles were fitted by the Szyskowski equation. It was found that the surface tensions at the critical micelle concentrations of these surfactants followed the sequence Brij 35 > Brij 98 > Brij 30. The air bubbles were most stable to coalescence in Brij 35 solution and least stable in Brij 30 solution. Coalescence in Brij 35 solution was hindered beyond a certain concentration of the surfactant. Stochastic distributions of coalescence time were observed in all surfactant systems. These distributions were fitted well by the stochastic model. Seven film-drainage models were used to predict the coalescence time. However, their predictions did not agree well with the mean values of the coalescence time distributions. Stability of foams was analyzed by the Ross−Miles test. The initial and residual foam heights were measured at each surfactant concentration. The foam heights followed the trends that are expected from the coalescence times of the bubbles. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102396v
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4484–4493[article] Coalescence of bubbles and stability of foams in brij surfactant systems [texte imprimé] / Sayantan Samanta, Auteur ; Pallab Ghosh, Auteur . - 2011 . - pp. 4484–4493.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4484–4493
Mots-clés : Coalescence air bubbles Aqueous solutions polyoxyethylene Résumé : This work presents coalescence of air bubbles and stability of foams in aqueous solutions of polyoxyethylene (4) lauryl ether (Brij 30), polyoxyethylene (23) lauryl ether (Brij 35), and polyoxyethylene (20) oleyl ether (Brij 98). Adsorption of these surfactants at the air−water interface was also studied. The surface tension profiles were fitted by the Szyskowski equation. It was found that the surface tensions at the critical micelle concentrations of these surfactants followed the sequence Brij 35 > Brij 98 > Brij 30. The air bubbles were most stable to coalescence in Brij 35 solution and least stable in Brij 30 solution. Coalescence in Brij 35 solution was hindered beyond a certain concentration of the surfactant. Stochastic distributions of coalescence time were observed in all surfactant systems. These distributions were fitted well by the stochastic model. Seven film-drainage models were used to predict the coalescence time. However, their predictions did not agree well with the mean values of the coalescence time distributions. Stability of foams was analyzed by the Ross−Miles test. The initial and residual foam heights were measured at each surfactant concentration. The foam heights followed the trends that are expected from the coalescence times of the bubbles. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102396v Exemplaires
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Titre : Cracks and ring bands of poly(3-hydroxybutyrate) on precrystallized poly(l-lactic acid) template Type de document : texte imprimé Auteurs : Siti Nurkhamidah, Auteur ; E. M. Woo, Auteur Année de publication : 2011 Article en page(s) : pp. 4494–4503 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Cracks Ring banded Precrystallized Poly Résumé : The lamellar morphology, cracks, and ring-banded spherulites were analyzed by allowing crystallization of poly(3-hydroxybutyrate) (PHB) on previously crystallized lamellar templates of poly(l-lactic acid) (PLLA) in mixtures of two semicrystalline polymers, PHB/PLLA (50/50) blend. PHB/PLLA blends were two-step crystallized first at crystallization temperature (Tc = 115−120 °C) and then cooled to ambient temperature. At Tc, only PLLA crystallized while PHB was an amorphous liquid; then at ambient temperature PHB crystallized and followed the preformed PLLA lamellar crystals. In addition, the amorphous PHB in PHB/PLLA blends induces the formation of ring-banded spherulites of PLLA at lower Tc. The radial short-segmental cracks aggregated on the circumferential bright bands occur in crystallized PHB/PLLA blends, which cannot be adequately interpreted by the temperature-induced coefficient of thermal expansion (CTE) upon cooling, but more likely they are related to interlamellar structuring of PLLA crystals at primary stage that are to be superimposed by the PHB crystals at later stage. The solvent etching of blends not only creates a valley−ridge depth profile in outer lamellar plates, but also exposes the internal branched crystals underneath the bright band (ridge after etching), which are housed underneath the concave portion of lamellae with lenticular-shaped radial cracks. PHB and PLLA in crystallized blends are intermixed in the dark bands, and these two lamellae also are interwound as radial bundles in the bright bands. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1024547
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4494–4503[article] Cracks and ring bands of poly(3-hydroxybutyrate) on precrystallized poly(l-lactic acid) template [texte imprimé] / Siti Nurkhamidah, Auteur ; E. M. Woo, Auteur . - 2011 . - pp. 4494–4503.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4494–4503
Mots-clés : Cracks Ring banded Precrystallized Poly Résumé : The lamellar morphology, cracks, and ring-banded spherulites were analyzed by allowing crystallization of poly(3-hydroxybutyrate) (PHB) on previously crystallized lamellar templates of poly(l-lactic acid) (PLLA) in mixtures of two semicrystalline polymers, PHB/PLLA (50/50) blend. PHB/PLLA blends were two-step crystallized first at crystallization temperature (Tc = 115−120 °C) and then cooled to ambient temperature. At Tc, only PLLA crystallized while PHB was an amorphous liquid; then at ambient temperature PHB crystallized and followed the preformed PLLA lamellar crystals. In addition, the amorphous PHB in PHB/PLLA blends induces the formation of ring-banded spherulites of PLLA at lower Tc. The radial short-segmental cracks aggregated on the circumferential bright bands occur in crystallized PHB/PLLA blends, which cannot be adequately interpreted by the temperature-induced coefficient of thermal expansion (CTE) upon cooling, but more likely they are related to interlamellar structuring of PLLA crystals at primary stage that are to be superimposed by the PHB crystals at later stage. The solvent etching of blends not only creates a valley−ridge depth profile in outer lamellar plates, but also exposes the internal branched crystals underneath the bright band (ridge after etching), which are housed underneath the concave portion of lamellae with lenticular-shaped radial cracks. PHB and PLLA in crystallized blends are intermixed in the dark bands, and these two lamellae also are interwound as radial bundles in the bright bands. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1024547 Exemplaires
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Titre : Stearic acid-coated chitosan-based interpenetrating polymer network microspheres : controlled release characteristics Type de document : texte imprimé Auteurs : Sudha C. Angadi, Auteur ; Lata S. Manjeshwar, Auteur ; Tejraj M. Aminabhavi, Auteur Année de publication : 2011 Article en page(s) : pp. 4504–4514 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Stearic acid Polymer Résumé : Novel pH-sensitive stearic acid-coated interpenetrating polymer network (IPN) blend microspheres of chitosan and gelatin were prepared by the emulsion cross-linking method using glutaraldehyde for the controlled release (CR) of isoniazid (INH), an antituberculosis drug. Coated as well as uncoated microspheres were developed and characterized by Fourier transform infrared (FTIR) to understand the chemical interactions and formation of the IPN blend structure as well as to confirm successful coating with the stearic acid. X-ray diffraction (XRD) indicated the distribution of INH, while differential scanning calorimetry (DSC) was used for investigating the thermal stability of the IPN blend matrices. Scanning electron microscopy (SEM) was used to distinguish between the morphologies of coated and uncoated microspheres. Coated microspheres were produced in the size range of 52 μm down to 502 nm with encapsulation efficiencies of 65−78%. Equilibrium swelling was studied in pH 1.2 and pH 7.4 buffer media, and the in vitro drug release showed the dependence of drug release on the cross-linking, blend ratio of the IPN matrix as well as stearic acid coating. The variations in the IPN blend ratio and cross-link density controlled the drug release up to 30 h, but the coated microspheres could reduce the burst release in the gastric stomach media, while enhancing in intestinal pH 7.4 media. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102479m
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4504–4514[article] Stearic acid-coated chitosan-based interpenetrating polymer network microspheres : controlled release characteristics [texte imprimé] / Sudha C. Angadi, Auteur ; Lata S. Manjeshwar, Auteur ; Tejraj M. Aminabhavi, Auteur . - 2011 . - pp. 4504–4514.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4504–4514
Mots-clés : Stearic acid Polymer Résumé : Novel pH-sensitive stearic acid-coated interpenetrating polymer network (IPN) blend microspheres of chitosan and gelatin were prepared by the emulsion cross-linking method using glutaraldehyde for the controlled release (CR) of isoniazid (INH), an antituberculosis drug. Coated as well as uncoated microspheres were developed and characterized by Fourier transform infrared (FTIR) to understand the chemical interactions and formation of the IPN blend structure as well as to confirm successful coating with the stearic acid. X-ray diffraction (XRD) indicated the distribution of INH, while differential scanning calorimetry (DSC) was used for investigating the thermal stability of the IPN blend matrices. Scanning electron microscopy (SEM) was used to distinguish between the morphologies of coated and uncoated microspheres. Coated microspheres were produced in the size range of 52 μm down to 502 nm with encapsulation efficiencies of 65−78%. Equilibrium swelling was studied in pH 1.2 and pH 7.4 buffer media, and the in vitro drug release showed the dependence of drug release on the cross-linking, blend ratio of the IPN matrix as well as stearic acid coating. The variations in the IPN blend ratio and cross-link density controlled the drug release up to 30 h, but the coated microspheres could reduce the burst release in the gastric stomach media, while enhancing in intestinal pH 7.4 media. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102479m Exemplaires
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Titre : A dynamic, distributed model of shell-and-tube heat exchangers undergoing crude oil fouling Type de document : texte imprimé Auteurs : Francesco Coletti, Auteur ; Sandro Macchietto, Auteur Année de publication : 2011 Article en page(s) : pp.4515–4533 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Dynamic Heat exchangers Résumé : Fouling in refinery preheat trains causes major energy inefficiencies, resulting in increased costs, greenhouse gas emissions, maintenance efforts, and safety hazards. Fouling deposition is not well understood, and current exchanger design and monitoring practices neglect the local effects and dynamics of fouling, in favor of lumped, steady-state, heuristic models (e.g., Tubular Exchanger Manufacturers Association (TEMA) fouling factors). In this paper, a dynamic, distributed model for a multipass shell-and-tube heat exchanger undergoing crude oil fouling is proposed. The model calculates fouling rates as a function of local conditions and time. It accounts for heat exchanger geometry, variation of oil physical properties with temperature, local accumulation of fouling deposits, and their structural change over time (aging). The interaction between fouling growth and fluid dynamics inside the tubes is accounted for by solving a moving boundary problem. Moreover, a procedure to analyze refinery data and support the estimation of a set of model parameters has been established. The model is validated using data from an ExxonMobil refinery and shows excellent agreement (less than 2% error) with primary plant measurements even when it is tested for its predictive capabilities over long periods (i.e., 1 year). It is concluded that the model can be used with confidence to identify and predict the fouling state of exchangers, to assess economic losses due to fouling, to support operating decisions such as planning of cleaning schedules, and to assist in the design and retrofit of heat exchangers. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901991g
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp.4515–4533[article] A dynamic, distributed model of shell-and-tube heat exchangers undergoing crude oil fouling [texte imprimé] / Francesco Coletti, Auteur ; Sandro Macchietto, Auteur . - 2011 . - pp.4515–4533.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp.4515–4533
Mots-clés : Dynamic Heat exchangers Résumé : Fouling in refinery preheat trains causes major energy inefficiencies, resulting in increased costs, greenhouse gas emissions, maintenance efforts, and safety hazards. Fouling deposition is not well understood, and current exchanger design and monitoring practices neglect the local effects and dynamics of fouling, in favor of lumped, steady-state, heuristic models (e.g., Tubular Exchanger Manufacturers Association (TEMA) fouling factors). In this paper, a dynamic, distributed model for a multipass shell-and-tube heat exchanger undergoing crude oil fouling is proposed. The model calculates fouling rates as a function of local conditions and time. It accounts for heat exchanger geometry, variation of oil physical properties with temperature, local accumulation of fouling deposits, and their structural change over time (aging). The interaction between fouling growth and fluid dynamics inside the tubes is accounted for by solving a moving boundary problem. Moreover, a procedure to analyze refinery data and support the estimation of a set of model parameters has been established. The model is validated using data from an ExxonMobil refinery and shows excellent agreement (less than 2% error) with primary plant measurements even when it is tested for its predictive capabilities over long periods (i.e., 1 year). It is concluded that the model can be used with confidence to identify and predict the fouling state of exchangers, to assess economic losses due to fouling, to support operating decisions such as planning of cleaning schedules, and to assist in the design and retrofit of heat exchangers. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901991g Exemplaires
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Titre : Fault diagnosis of batch chemical processes using a dynamic time warping (DTW)-based Artificial Immune System Type de document : texte imprimé Auteurs : Yiyang Dai, Auteur ; Jinsong Zhao, Auteur Année de publication : 2011 Article en page(s) : pp. 4534–4544 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Chemical processes Résumé : Fault diagnosis is important for ensuring chemical processes stability and safety. The strong nonlinearity and complexity of batch chemical processes make such diagnosis more difficult than that for continuous processes. In this paper, a new fault diagnosis methodology is proposed for batch chemical processes, based on an artificial immune system (AIS) and dynamic time warping (DTW) algorithm. The system generates diverse antibodies using known normal and fault samples and calculates the difference between the test data and the antibodies by the DTW algorithm. If the difference for an antibody is lower than a threshold, then the test data are deemed to be of the same type of this antibody’s fault. Its application to a simulated penicillin fermentation process demonstrates that the proposed AIS can meet the requirements for online dynamic fault diagnosis of batch processes and can diagnose new faults through self-learning. Compared with dynamic locus analysis and artificial neural networks, the proposed method has better capability in fault diagnosis of batch processes, especially when the number of historical fault samples is limited. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101465b
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4534–4544[article] Fault diagnosis of batch chemical processes using a dynamic time warping (DTW)-based Artificial Immune System [texte imprimé] / Yiyang Dai, Auteur ; Jinsong Zhao, Auteur . - 2011 . - pp. 4534–4544.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4534–4544
Mots-clés : Chemical processes Résumé : Fault diagnosis is important for ensuring chemical processes stability and safety. The strong nonlinearity and complexity of batch chemical processes make such diagnosis more difficult than that for continuous processes. In this paper, a new fault diagnosis methodology is proposed for batch chemical processes, based on an artificial immune system (AIS) and dynamic time warping (DTW) algorithm. The system generates diverse antibodies using known normal and fault samples and calculates the difference between the test data and the antibodies by the DTW algorithm. If the difference for an antibody is lower than a threshold, then the test data are deemed to be of the same type of this antibody’s fault. Its application to a simulated penicillin fermentation process demonstrates that the proposed AIS can meet the requirements for online dynamic fault diagnosis of batch processes and can diagnose new faults through self-learning. Compared with dynamic locus analysis and artificial neural networks, the proposed method has better capability in fault diagnosis of batch processes, especially when the number of historical fault samples is limited. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101465b Exemplaires
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Titre : Performance assessment by simulation of a gas-recycle oxosynthesis plant with propylene Recovery Type de document : texte imprimé Auteurs : Emil-Florin Tuţa, Auteur ; Grigore Bozga, Auteur Année de publication : 2011 Article en page(s) : pp. 4545–4552 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Gas Propylène Résumé : A simulation study of a C4 oxosynthesis plant (gas recycle technology) was performed by using the software package Hysys. The process thermodynamics was described by UNIQUAC property model. An important drawback of this technology is a significant loss of propylene by the purge gas stream. Computer simulations were carried out to evaluate the technical performance and the investment cost of a proposed revamping scheme, allowing an advanced propylene recovery from purge gases. The cost evaluations performed with Aspen Economic Evaluation are indicating that the revamping investment cost is equivalent to the propylene savings during a three years plant running period. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101731f
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4545–4552[article] Performance assessment by simulation of a gas-recycle oxosynthesis plant with propylene Recovery [texte imprimé] / Emil-Florin Tuţa, Auteur ; Grigore Bozga, Auteur . - 2011 . - pp. 4545–4552.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4545–4552
Mots-clés : Gas Propylène Résumé : A simulation study of a C4 oxosynthesis plant (gas recycle technology) was performed by using the software package Hysys. The process thermodynamics was described by UNIQUAC property model. An important drawback of this technology is a significant loss of propylene by the purge gas stream. Computer simulations were carried out to evaluate the technical performance and the investment cost of a proposed revamping scheme, allowing an advanced propylene recovery from purge gases. The cost evaluations performed with Aspen Economic Evaluation are indicating that the revamping investment cost is equivalent to the propylene savings during a three years plant running period. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101731f Exemplaires
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Titre : Optimal design and operation of flexible energy polygeneration systems Type de document : texte imprimé Auteurs : Yang Chen, Auteur ; Thomas A. Adams, Auteur ; Paul I. Barton, Auteur Année de publication : 2011 Article en page(s) : pp. 4553–4566 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Flexible energy Polygeneration systems Résumé : The optimal design and operation of flexible polygeneration systems using coal and biomass to coproduce power, liquid fuels, and chemicals is studied. In flexible systems, the various product rates change throughout the lifetime of the plant in response to market conditions in different scenarios. A two-stage programming formulation is proposed to optimize simultaneously the design decision variables and the operational decision variables in all scenarios. The optimal product portfolios, equipment capacity usages, and CO2 emissions of flexible polygeneration systems under different market conditions are discussed. In general, flexible polygeneration systems achieve higher net present values than static ones for the same oil price and carbon tax. Higher net present values can be obtained with increasing operational flexibility. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1021267
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4553–4566[article] Optimal design and operation of flexible energy polygeneration systems [texte imprimé] / Yang Chen, Auteur ; Thomas A. Adams, Auteur ; Paul I. Barton, Auteur . - 2011 . - pp. 4553–4566.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4553–4566
Mots-clés : Flexible energy Polygeneration systems Résumé : The optimal design and operation of flexible polygeneration systems using coal and biomass to coproduce power, liquid fuels, and chemicals is studied. In flexible systems, the various product rates change throughout the lifetime of the plant in response to market conditions in different scenarios. A two-stage programming formulation is proposed to optimize simultaneously the design decision variables and the operational decision variables in all scenarios. The optimal product portfolios, equipment capacity usages, and CO2 emissions of flexible polygeneration systems under different market conditions are discussed. In general, flexible polygeneration systems achieve higher net present values than static ones for the same oil price and carbon tax. Higher net present values can be obtained with increasing operational flexibility. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1021267 Exemplaires
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Titre : Optimal H2 IMC-PID controller with set-point weighting for time-delayed unstable processes Type de document : texte imprimé Auteurs : Anggi A. Nasution, Auteur ; Jyh-Cheng Jeng, Auteur ; Hsiao-Ping Huang, Auteur Année de publication : 2011 Article en page(s) : pp. 4567–4578 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : optimal H2 Unstable processes Résumé : This paper presents the synthesis of optimal H2 proportional−integral−derivative (PID) controller from internal model control (IMC) design for unstable processes with single right-half-plane (RHP) pole and time delay. The H2 optimal closed-loop transfer functions, for unit set-point and disturbance inputs, are first derived to synthesize the ideal controller. This ideal controller is then used to obtain PID parameters by the approach of Maclaurin series approximation. The proposed PID tuning is compared with those resulting from some of the recently developed desired closed-loop transfer functions in the literature in terms of performance and robustness both for set-point tracking and input disturbance rejection. Moreover, to improve the performance of set-point tracking, this paper also presents the two degrees of freedom controller design, which can be further derived as a set-point weighted PID controller. The tuning formulas for these weighting parameters on proportional and derivative modes are thus developed. Simulation examples are provided to demonstrate the effectiveness of the proposed tuning method DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1021688
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4567–4578[article] Optimal H2 IMC-PID controller with set-point weighting for time-delayed unstable processes [texte imprimé] / Anggi A. Nasution, Auteur ; Jyh-Cheng Jeng, Auteur ; Hsiao-Ping Huang, Auteur . - 2011 . - pp. 4567–4578.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4567–4578
Mots-clés : optimal H2 Unstable processes Résumé : This paper presents the synthesis of optimal H2 proportional−integral−derivative (PID) controller from internal model control (IMC) design for unstable processes with single right-half-plane (RHP) pole and time delay. The H2 optimal closed-loop transfer functions, for unit set-point and disturbance inputs, are first derived to synthesize the ideal controller. This ideal controller is then used to obtain PID parameters by the approach of Maclaurin series approximation. The proposed PID tuning is compared with those resulting from some of the recently developed desired closed-loop transfer functions in the literature in terms of performance and robustness both for set-point tracking and input disturbance rejection. Moreover, to improve the performance of set-point tracking, this paper also presents the two degrees of freedom controller design, which can be further derived as a set-point weighted PID controller. The tuning formulas for these weighting parameters on proportional and derivative modes are thus developed. Simulation examples are provided to demonstrate the effectiveness of the proposed tuning method DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1021688 Exemplaires
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Titre : Plantwide control of a hybrid integrated gasification combined cycle/methanol plant Type de document : texte imprimé Auteurs : Patrick J. Robinson, Auteur ; William L. Luyben, Auteur Année de publication : 2011 Article en page(s) : pp. 4579–4594 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Gasification Résumé : The coupling of an integrated gasification combined cycle (IGCC) electric power plant with a hydrogen-consuming chemical (methanol) plant can handle swings in electric power demand. Hydrogen gas from the combustion turbine and synthesis gas from the gasifier can be diverted to a methanol plant for the production of an easily stored, hydrogen-consuming liquid product. This paper extends previous work on dynamic studies of a gasifier and downstream units of an IGCC to explore the steady-state economic design, control, and successful turndown of the methanol plant. The plantwide control structure and interaction among units are also shown. The methanol plant is sized to reduce the power generation from an IGCC by 50%, producing a high-purity methanol stream of 99.5 mol %. Regulatory control structures are designed and play a significant role for the successful turndown of the methanol plant to 20% capacity. The exit temperature of the cooled tubular methanol reactor is controlled instead of a peak temperature within the reactor. During times of low capacity and minimum vapor rate within the distillation column, tray temperature is controlled by recycling a portion of the distillate and bottoms back upstream so that temperature can be effectively controlled by manipulating feed flow rate. The gasifier feed is held constant. The product hydrogen from the IGCC is fed to the combustion turbine as required by electric power demand. Synthesis gas fed into the methanol plant maintains pressure of the hydrogen stream. Make-up hydrogen is also fed to the methanol plant to maintain reaction stoichiometry by controlling the carbon monoxide composition of the recycle gas in the methanol plant. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102219k
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4579–4594[article] Plantwide control of a hybrid integrated gasification combined cycle/methanol plant [texte imprimé] / Patrick J. Robinson, Auteur ; William L. Luyben, Auteur . - 2011 . - pp. 4579–4594.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4579–4594
Mots-clés : Gasification Résumé : The coupling of an integrated gasification combined cycle (IGCC) electric power plant with a hydrogen-consuming chemical (methanol) plant can handle swings in electric power demand. Hydrogen gas from the combustion turbine and synthesis gas from the gasifier can be diverted to a methanol plant for the production of an easily stored, hydrogen-consuming liquid product. This paper extends previous work on dynamic studies of a gasifier and downstream units of an IGCC to explore the steady-state economic design, control, and successful turndown of the methanol plant. The plantwide control structure and interaction among units are also shown. The methanol plant is sized to reduce the power generation from an IGCC by 50%, producing a high-purity methanol stream of 99.5 mol %. Regulatory control structures are designed and play a significant role for the successful turndown of the methanol plant to 20% capacity. The exit temperature of the cooled tubular methanol reactor is controlled instead of a peak temperature within the reactor. During times of low capacity and minimum vapor rate within the distillation column, tray temperature is controlled by recycling a portion of the distillate and bottoms back upstream so that temperature can be effectively controlled by manipulating feed flow rate. The gasifier feed is held constant. The product hydrogen from the IGCC is fed to the combustion turbine as required by electric power demand. Synthesis gas fed into the methanol plant maintains pressure of the hydrogen stream. Make-up hydrogen is also fed to the methanol plant to maintain reaction stoichiometry by controlling the carbon monoxide composition of the recycle gas in the methanol plant. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102219k Exemplaires
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Titre : Design and control of a methyl methacrylate separation process with a middle decanter Type de document : texte imprimé Auteurs : Yi Chang Wu, Auteur ; C. S. Hsu, Auteur ; Hsiao-Ping Huang, Auteur Année de publication : 2011 Article en page(s) : pp. 4595–4607 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Methyl Methacrylate Separation process Résumé : In an industrial process to produce methyl methacrylate, a mixture including methyl methacrylate, methanol, and water needs to be separated. The methyl methacrylate and water are designed to be drawn out of this separation process as two product streams while methanol as an excess reactant should be recycled back to the esterification reactor. An industrial feasible design flowsheet includes three columns, a decanter and two internal recycle streams. In this work, a simple design flowsheet is devised with a distillation column, a bottom decanter, and a stripper. This column/decanter/stripper design can further be simplified into an even simpler design flowsheet with only one distillation column with sidedraw and a middle decanter. Optimal design and dynamic control of this simplified separation process are investigated in this paper. It is shown that the product purity specifications can be maintained despite feed disturbances by holding a tray temperature above the sidedraw location and another one below the sidedraw location. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102570n
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4595–4607[article] Design and control of a methyl methacrylate separation process with a middle decanter [texte imprimé] / Yi Chang Wu, Auteur ; C. S. Hsu, Auteur ; Hsiao-Ping Huang, Auteur . - 2011 . - pp. 4595–4607.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4595–4607
Mots-clés : Methyl Methacrylate Separation process Résumé : In an industrial process to produce methyl methacrylate, a mixture including methyl methacrylate, methanol, and water needs to be separated. The methyl methacrylate and water are designed to be drawn out of this separation process as two product streams while methanol as an excess reactant should be recycled back to the esterification reactor. An industrial feasible design flowsheet includes three columns, a decanter and two internal recycle streams. In this work, a simple design flowsheet is devised with a distillation column, a bottom decanter, and a stripper. This column/decanter/stripper design can further be simplified into an even simpler design flowsheet with only one distillation column with sidedraw and a middle decanter. Optimal design and dynamic control of this simplified separation process are investigated in this paper. It is shown that the product purity specifications can be maintained despite feed disturbances by holding a tray temperature above the sidedraw location and another one below the sidedraw location. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102570n Exemplaires
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Titre : Combined model of mass-transfer coefficients for clean and contaminated liquid−liquid systems Type de document : texte imprimé Auteurs : A. Haghdoost, Auteur ; Asghar M. Dehkordi, Auteur ; M. Darbandi, Auteur Année de publication : 2011 Article en page(s) : pp. 4608–4617 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Mass transfer Liquid liquid systems Résumé : Mass-transfer rates to and from drops in liquid−liquid extraction processes are often reduced by the presence of contaminants. To design an industrial extractor, it is essential to consider this contamination effect in a quantitative manner. To achieve this goal, an experimental investigation was conducted on the mass transfer into single drops for n-butanol−succinic acid−water, as the recommended test system by the European Federation of Chemical Engineering (EFCE). The effects of anionic (sodium dodecyl sulfate, SDS), cationic (dodecyl trimethyl ammonium chloride, DTMAC), and nonionic (octylphenol decaethylene glycol ether, Triton X-100) surfactants on the hydrodynamic and mass-transfer parameters such as mean drop size, average velocity, and the overall mass-transfer coefficient were thoroughly investigated. On the basis of experimental results, a model for surfactant effect on the mass-transfer coefficient in a system with unknown type and amount of contaminant was presented. This model is especially applicable in industrial processes in which contaminants have unknown sources and types. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901076f
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4608–4617[article] Combined model of mass-transfer coefficients for clean and contaminated liquid−liquid systems [texte imprimé] / A. Haghdoost, Auteur ; Asghar M. Dehkordi, Auteur ; M. Darbandi, Auteur . - 2011 . - pp. 4608–4617.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4608–4617
Mots-clés : Mass transfer Liquid liquid systems Résumé : Mass-transfer rates to and from drops in liquid−liquid extraction processes are often reduced by the presence of contaminants. To design an industrial extractor, it is essential to consider this contamination effect in a quantitative manner. To achieve this goal, an experimental investigation was conducted on the mass transfer into single drops for n-butanol−succinic acid−water, as the recommended test system by the European Federation of Chemical Engineering (EFCE). The effects of anionic (sodium dodecyl sulfate, SDS), cationic (dodecyl trimethyl ammonium chloride, DTMAC), and nonionic (octylphenol decaethylene glycol ether, Triton X-100) surfactants on the hydrodynamic and mass-transfer parameters such as mean drop size, average velocity, and the overall mass-transfer coefficient were thoroughly investigated. On the basis of experimental results, a model for surfactant effect on the mass-transfer coefficient in a system with unknown type and amount of contaminant was presented. This model is especially applicable in industrial processes in which contaminants have unknown sources and types. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901076f Exemplaires
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Titre : On the solubility of three disperse anthraquinone dyes in supercritical carbon dioxide : new experimental data and correlation Type de document : texte imprimé Auteurs : Jose P. Coelho, Auteur ; Andrea F. Mendonça, Auteur ; Antonio F. Palavra, Auteur Année de publication : 2011 Article en page(s) : pp. 4618–4624 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Solubility measurements Anthraquinone Dioxide Résumé : Solubility measurements of quinizarin (1,4-dihydroxyanthraquinone), disperse red 9 (1-(methylamino) anthraquinone), and disperse blue 14 (1,4-bis(methylamino)anthraquinone) in supercritical carbon dioxide (SC CO2) were carried out in a flow type apparatus, at a temperature range from (333.2 to 393.2) K and at pressures from (12.0 to 40.0) MPa. Mole fraction solubility of the three dyes decreases in the order quinizarin (2.9 × 10−6 to 2.9.10−4), red 9 (1.4 × 10−6 to 3.2 × 10−4), and blue 14 (7.8 × 10−8 to 2.2 × 10−5). Four semiempirical density-based models were used to correlate the solubility of the dyes in the SC CO2. From the correlation results, the total heat of reaction, heat of vaporization plus the heat of solvation of the solute, were calculated and compared with the results presented in the literature. The solubilities of the three dyes were correlated also applying the Soave−Redlich−Kwong cubic equation of state (SRK CEoS) with classical mixing rules, and the physical properties required for the modeling were estimated and reported. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102028x
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4618–4624[article] On the solubility of three disperse anthraquinone dyes in supercritical carbon dioxide : new experimental data and correlation [texte imprimé] / Jose P. Coelho, Auteur ; Andrea F. Mendonça, Auteur ; Antonio F. Palavra, Auteur . - 2011 . - pp. 4618–4624.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4618–4624
Mots-clés : Solubility measurements Anthraquinone Dioxide Résumé : Solubility measurements of quinizarin (1,4-dihydroxyanthraquinone), disperse red 9 (1-(methylamino) anthraquinone), and disperse blue 14 (1,4-bis(methylamino)anthraquinone) in supercritical carbon dioxide (SC CO2) were carried out in a flow type apparatus, at a temperature range from (333.2 to 393.2) K and at pressures from (12.0 to 40.0) MPa. Mole fraction solubility of the three dyes decreases in the order quinizarin (2.9 × 10−6 to 2.9.10−4), red 9 (1.4 × 10−6 to 3.2 × 10−4), and blue 14 (7.8 × 10−8 to 2.2 × 10−5). Four semiempirical density-based models were used to correlate the solubility of the dyes in the SC CO2. From the correlation results, the total heat of reaction, heat of vaporization plus the heat of solvation of the solute, were calculated and compared with the results presented in the literature. The solubilities of the three dyes were correlated also applying the Soave−Redlich−Kwong cubic equation of state (SRK CEoS) with classical mixing rules, and the physical properties required for the modeling were estimated and reported. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102028x Exemplaires
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Titre : Studies on the sorption of cadmium(II), zinc(II), and copper(II) with PTFE selective resin containing primary amine N1923 and cyanex923 Type de document : texte imprimé Auteurs : Zhao Xiaowei, Auteur ; Song Naizhong, Auteur ; Jia Qiong, Auteur Année de publication : 2011 Article en page(s) : pp. 4625–4630 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Adsorption Cadmium Zinc Copper Résumé : The adsorption of Cd(II), Zn(II), and Cu(II) from chloride medium with PTFE Selective Resin containing primary amine N1923 and Cyanex923 has been investigated. The influences of the pH of solution and the contact time on the adsorption have been discussed, and the appropriate experimental conditions have been obtained. The adsorption kinetics investigations indicate that the adsorption rate of Cd(II), Zn(II), and Cu(II) on the Selective Resin can be well described by the pseudosecond-order kinetics model, and the adsorption capacities calculated by the pseudosecond-order rate model are close to those determined by actual measurements. Both Langmuir and Freundlich isotherm models match the experimental data very well, and the maximum adsorption capacity (qmax) has been calculated to be 263.16 mg Cd(II)/g·resin, 54.95 mg Zn(II)/g·resin, and 39.84 mg Cu(II)/g·resin, respectively. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101493r
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4625–4630[article] Studies on the sorption of cadmium(II), zinc(II), and copper(II) with PTFE selective resin containing primary amine N1923 and cyanex923 [texte imprimé] / Zhao Xiaowei, Auteur ; Song Naizhong, Auteur ; Jia Qiong, Auteur . - 2011 . - pp. 4625–4630.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4625–4630
Mots-clés : Adsorption Cadmium Zinc Copper Résumé : The adsorption of Cd(II), Zn(II), and Cu(II) from chloride medium with PTFE Selective Resin containing primary amine N1923 and Cyanex923 has been investigated. The influences of the pH of solution and the contact time on the adsorption have been discussed, and the appropriate experimental conditions have been obtained. The adsorption kinetics investigations indicate that the adsorption rate of Cd(II), Zn(II), and Cu(II) on the Selective Resin can be well described by the pseudosecond-order kinetics model, and the adsorption capacities calculated by the pseudosecond-order rate model are close to those determined by actual measurements. Both Langmuir and Freundlich isotherm models match the experimental data very well, and the maximum adsorption capacity (qmax) has been calculated to be 263.16 mg Cd(II)/g·resin, 54.95 mg Zn(II)/g·resin, and 39.84 mg Cu(II)/g·resin, respectively. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101493r Exemplaires
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Titre : Hydrodynamics of ceramic sponges in countercurrent flow Type de document : texte imprimé Auteurs : Julia Grosse, Auteur ; Matthias Kind, Auteur Année de publication : 2011 Article en page(s) : pp. 4631–4640 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydrodynamics Ceramic Sponges Résumé : A broad range of ceramic sponge types regarding porosity, pore size, and material was investigated experimentally in order to determine liquid holdup as well as wet pressure drop and operation limits. The observed values for the holdup are higher than those for state-of-the-art random and structured packings. The onset of flooding occurs at relatively low gas loads, but the operation range can be significantly enlarged by using a sponge with a cone-shaped bottom as drainage enhancer. Effects of stacking can be shown especially for the static liquid holdup. Possible applications are, for example, reactive rectification, where the continuous solid and the ceramic material as catalyst carrier are of advantage. The experimental values are compared with established correlations from the literature for conventional column internals. In general, those are able to describe the behavior of sponge structures, although the deviations are bigger than observed for other column internals. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101514w
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4631–4640[article] Hydrodynamics of ceramic sponges in countercurrent flow [texte imprimé] / Julia Grosse, Auteur ; Matthias Kind, Auteur . - 2011 . - pp. 4631–4640.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4631–4640
Mots-clés : Hydrodynamics Ceramic Sponges Résumé : A broad range of ceramic sponge types regarding porosity, pore size, and material was investigated experimentally in order to determine liquid holdup as well as wet pressure drop and operation limits. The observed values for the holdup are higher than those for state-of-the-art random and structured packings. The onset of flooding occurs at relatively low gas loads, but the operation range can be significantly enlarged by using a sponge with a cone-shaped bottom as drainage enhancer. Effects of stacking can be shown especially for the static liquid holdup. Possible applications are, for example, reactive rectification, where the continuous solid and the ceramic material as catalyst carrier are of advantage. The experimental values are compared with established correlations from the literature for conventional column internals. In general, those are able to describe the behavior of sponge structures, although the deviations are bigger than observed for other column internals. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101514w Exemplaires
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Titre : An implicit FEM solution of a PBE model of gibbsite crystallization with constant and nonlinear kinetics Type de document : texte imprimé Auteurs : Andrey V. Bekker, Auteur ; Iztok Livk, Auteur Année de publication : 2011 Article en page(s) : pp. 4641–4652 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Crystallization Nonlinear kinetics Résumé : Numerical solution for a 1-D dynamic population balance crystallization model that includes gibbsite secondary nucleation and crystal growth kinetics was developed. The implemented numerical algorithm combines an implicit Galerkin formulation of the finite element method (FEM) with Newton iterations, variable Gear-type time-step and adaptive nonuniform mesh strategies. The numerical solution of the crystallization model is compared to the analytical solution derived for the case of constant gibbsite crystallization kinetics. For this case, it is shown that the numerical solution was considerably stabilized with the introduction of the artificial diffusion term and reduction of the relative error of Newton’s iterative step. Furthermore, the numerical algorithm is tested for the case of nonlinear gibbsite crystallization kinetics demonstrating its ability to deliver consistent solutions for both nucleation and crystal growth dominant cases. In each of the cases considered, the model solution, valid for an isothermal batch homogenously mixed crystallizer, predicted evolutions of the crystal size distribution (CSD) and relative supersaturation. Using the developed modeling technique, it is also shown that the initial seed loading strongly influences the shape of the product CSD, leading in some cases to multimodal CSDs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1019326
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4641–4652[article] An implicit FEM solution of a PBE model of gibbsite crystallization with constant and nonlinear kinetics [texte imprimé] / Andrey V. Bekker, Auteur ; Iztok Livk, Auteur . - 2011 . - pp. 4641–4652.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4641–4652
Mots-clés : Crystallization Nonlinear kinetics Résumé : Numerical solution for a 1-D dynamic population balance crystallization model that includes gibbsite secondary nucleation and crystal growth kinetics was developed. The implemented numerical algorithm combines an implicit Galerkin formulation of the finite element method (FEM) with Newton iterations, variable Gear-type time-step and adaptive nonuniform mesh strategies. The numerical solution of the crystallization model is compared to the analytical solution derived for the case of constant gibbsite crystallization kinetics. For this case, it is shown that the numerical solution was considerably stabilized with the introduction of the artificial diffusion term and reduction of the relative error of Newton’s iterative step. Furthermore, the numerical algorithm is tested for the case of nonlinear gibbsite crystallization kinetics demonstrating its ability to deliver consistent solutions for both nucleation and crystal growth dominant cases. In each of the cases considered, the model solution, valid for an isothermal batch homogenously mixed crystallizer, predicted evolutions of the crystal size distribution (CSD) and relative supersaturation. Using the developed modeling technique, it is also shown that the initial seed loading strongly influences the shape of the product CSD, leading in some cases to multimodal CSDs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1019326 Exemplaires
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Titre : Mathematical analysis of the meso-scale flow field in spiral-wound membrane modules Type de document : texte imprimé Auteurs : Margaritis Kostoglou, Auteur ; Anastasios J. Karabelas, Auteur Année de publication : 2011 Article en page(s) : pp. 4653–4666 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Mathematical analysis Mesoscale hydrodynamic equations Résumé : The use of flat-sheet, spiral-wound, membrane modules for reverse osmosis and nanofiltration applications is very extensive. Design and performance optimization of these modules requires sound mathematical modeling. This study focuses on the mathematical analysis of the mesoscale hydrodynamic equations for the narrow channels with spacers, of the entire membrane sheet, previously derived from the microscale momentum conservation laws14. The mathematical problem is enhanced by considering a spatial dependence of the retentate channel and membrane permeabilities to account for fouling/scaling, aiming at future use of the proposed techniques to simulate long time fouling dynamic behavior of the process. The formal mathematical treatment of the original problem leads to several levels of approximation (depending on the problem parameter values) which admit either analytical or numerical solutions with reduced dimensionality, or numerical solutions with reduced convergence difficulties. To confirm the validity of conclusions obtained by following these procedures, several results from simplified cases are compared with numerical solutions of the original problem. Furthermore, all possible simplifications and analytical solutions of the particular problem have been obtained, as well as the conditions under which they hold, thus forming the basis for more comprehensive modeling, including mass transfer and scaling/fouling phenomena. Specific criteria are also provided for selecting appropriate simplified solutions to specific cases, helpful in the development of flow and membrane fouling simulators. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102083j
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4653–4666[article] Mathematical analysis of the meso-scale flow field in spiral-wound membrane modules [texte imprimé] / Margaritis Kostoglou, Auteur ; Anastasios J. Karabelas, Auteur . - 2011 . - pp. 4653–4666.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4653–4666
Mots-clés : Mathematical analysis Mesoscale hydrodynamic equations Résumé : The use of flat-sheet, spiral-wound, membrane modules for reverse osmosis and nanofiltration applications is very extensive. Design and performance optimization of these modules requires sound mathematical modeling. This study focuses on the mathematical analysis of the mesoscale hydrodynamic equations for the narrow channels with spacers, of the entire membrane sheet, previously derived from the microscale momentum conservation laws14. The mathematical problem is enhanced by considering a spatial dependence of the retentate channel and membrane permeabilities to account for fouling/scaling, aiming at future use of the proposed techniques to simulate long time fouling dynamic behavior of the process. The formal mathematical treatment of the original problem leads to several levels of approximation (depending on the problem parameter values) which admit either analytical or numerical solutions with reduced dimensionality, or numerical solutions with reduced convergence difficulties. To confirm the validity of conclusions obtained by following these procedures, several results from simplified cases are compared with numerical solutions of the original problem. Furthermore, all possible simplifications and analytical solutions of the particular problem have been obtained, as well as the conditions under which they hold, thus forming the basis for more comprehensive modeling, including mass transfer and scaling/fouling phenomena. Specific criteria are also provided for selecting appropriate simplified solutions to specific cases, helpful in the development of flow and membrane fouling simulators. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102083j Exemplaires
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Titre : Improvement of essential oil steam distillation by microwave pretreatment Type de document : texte imprimé Auteurs : A. Navarrete, Auteur ; S. Wallraf, Auteur ; R. B. Mato, Auteur Année de publication : 2011 Article en page(s) : pp. 4667–4671 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Microwave irradiation Pretreatment method Essential oil Résumé : Microwave irradiation is proposed as a pretreatment method to accelerate the conventional steam distillation of rosemary essential oil. Microwave extraction methods are based on the capacity of radiation to break the oil-containing glands, allowing faster extraction rates. An analytical method is developed to quantify the fraction of essential oil inside and outside trichomes. This method is used to evaluate the effect of microwaves on the fraction of oil released outside of trichome glands. Steam distillation rates are measured after using different microwave pretreatment energies, and the influence of liquid moisture released from plant cells is also analyzed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102218g
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4667–4671[article] Improvement of essential oil steam distillation by microwave pretreatment [texte imprimé] / A. Navarrete, Auteur ; S. Wallraf, Auteur ; R. B. Mato, Auteur . - 2011 . - pp. 4667–4671.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4667–4671
Mots-clés : Microwave irradiation Pretreatment method Essential oil Résumé : Microwave irradiation is proposed as a pretreatment method to accelerate the conventional steam distillation of rosemary essential oil. Microwave extraction methods are based on the capacity of radiation to break the oil-containing glands, allowing faster extraction rates. An analytical method is developed to quantify the fraction of essential oil inside and outside trichomes. This method is used to evaluate the effect of microwaves on the fraction of oil released outside of trichome glands. Steam distillation rates are measured after using different microwave pretreatment energies, and the influence of liquid moisture released from plant cells is also analyzed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102218g Exemplaires
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Titre : Gas - liquid - liquid slug flow for improving liquid - liquid extraction in miniaturized channels Type de document : texte imprimé Auteurs : Nobuaki Aoki, Auteur ; Ryuichi Ando, Auteur ; Kazuhiro Mae, Auteur Année de publication : 2011 Article en page(s) : pp. 4672–4677 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Gas Liquid Résumé : To increase the maximum flow rate that enables slug flow formation in miniaturized channels, gas-phase slugs are added in a liquid−liquid slug flow to form a gas−liquid−liquid slug flow. Effects of channel size, void fraction (ratio of volumetric flow rate of gas phase to that of total flow rate), and volume ratio of aqueous phase to organic phase on flow regime are examined. Results indicate that the total liquid-phase flow rate that forms a stable gas−liquid−liquid slug flow increases up to 200 mL/min with air addition (void fraction > 0.1) in a poly(tetrafluoroethylene) (PTFE) tube (inner diameter (i.d.), 3 mm). The mass-transfer rate in the gas−liquid−liquid slug flow was also high because internal circulation flow is enhanced by increased flow rate. The mass-transfer coefficient was then correlated with the channel i.d. and the flow velocity. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1024326
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4672–4677[article] Gas - liquid - liquid slug flow for improving liquid - liquid extraction in miniaturized channels [texte imprimé] / Nobuaki Aoki, Auteur ; Ryuichi Ando, Auteur ; Kazuhiro Mae, Auteur . - 2011 . - pp. 4672–4677.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4672–4677
Mots-clés : Gas Liquid Résumé : To increase the maximum flow rate that enables slug flow formation in miniaturized channels, gas-phase slugs are added in a liquid−liquid slug flow to form a gas−liquid−liquid slug flow. Effects of channel size, void fraction (ratio of volumetric flow rate of gas phase to that of total flow rate), and volume ratio of aqueous phase to organic phase on flow regime are examined. Results indicate that the total liquid-phase flow rate that forms a stable gas−liquid−liquid slug flow increases up to 200 mL/min with air addition (void fraction > 0.1) in a poly(tetrafluoroethylene) (PTFE) tube (inner diameter (i.d.), 3 mm). The mass-transfer rate in the gas−liquid−liquid slug flow was also high because internal circulation flow is enhanced by increased flow rate. The mass-transfer coefficient was then correlated with the channel i.d. and the flow velocity. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1024326 Exemplaires
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Titre : A feasible post-treatment of drying and rewetting for preparation of high-flux pluronic F127/polyethersulfone nanofiltration membranes Type de document : texte imprimé Auteurs : Yan Zhang, Auteur ; Su, Yanlei, Auteur ; Wenjuan Chen, Auteur Année de publication : 2011 Article en page(s) : pp.4678–4685 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Pluronic Nanofiltration membranes Résumé : Pluronic F127/polyethersulfone (PES) blend nanofiltration membranes were fabricated by varying polymer weight ratios of WF127/WPES in casting solutions from 0.0 to 100.0 wt %. The initial wet membranes prepared via the phase inversion method were post-treated by drying at room temperature and then immersion into water for rewetting to obtain Pluronic F127/PES nanofiltration membranes. Membrane shrinkage and swelling, cross section and surface morphologies, water uptake, surface hydrophilicity, X-ray diffraction pattern, water flux, and rejection of dyes for Pluronic F127/PES nanofiltration membranes were investigated. The introduction of Pluronic F127 into PES membranes can substantially alleviate the membrane shrinkage during drying treatment. All of the prepared Pluronic F127/PES nanofiltration membranes can completely reject Alcian blue with a molecular weight of 1299. The water permeance of Pluronic F127/PES nanofiltration membrane at WF127/WPES of 80% is as high as 176.2 L/(m2 h MPa). After long-term immersion into sodium hypochlorite solution, Pluronic F127/PES nanofiltration membranes still keep over 95.7% rejection of Alcian blue. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102463k
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp.4678–4685[article] A feasible post-treatment of drying and rewetting for preparation of high-flux pluronic F127/polyethersulfone nanofiltration membranes [texte imprimé] / Yan Zhang, Auteur ; Su, Yanlei, Auteur ; Wenjuan Chen, Auteur . - 2011 . - pp.4678–4685.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp.4678–4685
Mots-clés : Pluronic Nanofiltration membranes Résumé : Pluronic F127/polyethersulfone (PES) blend nanofiltration membranes were fabricated by varying polymer weight ratios of WF127/WPES in casting solutions from 0.0 to 100.0 wt %. The initial wet membranes prepared via the phase inversion method were post-treated by drying at room temperature and then immersion into water for rewetting to obtain Pluronic F127/PES nanofiltration membranes. Membrane shrinkage and swelling, cross section and surface morphologies, water uptake, surface hydrophilicity, X-ray diffraction pattern, water flux, and rejection of dyes for Pluronic F127/PES nanofiltration membranes were investigated. The introduction of Pluronic F127 into PES membranes can substantially alleviate the membrane shrinkage during drying treatment. All of the prepared Pluronic F127/PES nanofiltration membranes can completely reject Alcian blue with a molecular weight of 1299. The water permeance of Pluronic F127/PES nanofiltration membrane at WF127/WPES of 80% is as high as 176.2 L/(m2 h MPa). After long-term immersion into sodium hypochlorite solution, Pluronic F127/PES nanofiltration membranes still keep over 95.7% rejection of Alcian blue. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102463k Exemplaires
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Titre : Surface modified, collapsible controlled pore glass materials for sequestration and immobilization of trivalent metal ions Type de document : texte imprimé Auteurs : Ilya A. Shkrob, Auteur ; Angela R. Tisch, Auteur ; Timothy W. Marin, Auteur Année de publication : 2011 Article en page(s) : pp. 4686–4696 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Chemical modification X-ray absorption Metal ions Résumé : We report a one-pot method for sequestration, containment, and immobilization of lanthanide (Ln) ions from dilute aqueous waste streams. The approach is based on the use of collapsible, surface modified controlled pore glass (CPG) nanomaterials. We present several approaches for a single-step chemical modification of 3-propylaminated CPGs that yield highly efficient Ln-extracting materials with distribution coefficients exceeding 10000 mL/g. The resulting Ln complexes were studied using X-ray absorption, magnetic resonance, and time-resolved luminescence spectroscopies. One of these CPG materials involving an imidodi(methanediphosphate) moiety demonstrated high extraction efficacy, significant ionic radius sensitivity, and exceptional tolerance to masking agents, which is conducive to its use for removal of traces of radionuclide ions from aqueous TALSPEAK raffinate (trivalent actinide−lanthanide separation by phosphorus reagent extraction from aqueous complexes process used in processing of spent nuclear fuel). The glass loaded with the extracted metal ions can be calcined and sintered at 1100 °C, yielding fused material that buries Ln ions in the vitreous matrix. This processing temperature is significantly lower than 1700 °C that is required for direct vitrification of lanthanide oxides in high-silica glass. X-ray absorption spectroscopy and acid leaching tests indicate that the immobilized ions are isolated and dispersed in the fused glass matrix. Thus, the method integrates Ln ions into the glass network. The resulting glass can be used for temporary storage or as the source of silica for production of borosilicate waste forms that are used for long-term disposal of high level radioactive waste. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102494r
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4686–4696[article] Surface modified, collapsible controlled pore glass materials for sequestration and immobilization of trivalent metal ions [texte imprimé] / Ilya A. Shkrob, Auteur ; Angela R. Tisch, Auteur ; Timothy W. Marin, Auteur . - 2011 . - pp. 4686–4696.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4686–4696
Mots-clés : Chemical modification X-ray absorption Metal ions Résumé : We report a one-pot method for sequestration, containment, and immobilization of lanthanide (Ln) ions from dilute aqueous waste streams. The approach is based on the use of collapsible, surface modified controlled pore glass (CPG) nanomaterials. We present several approaches for a single-step chemical modification of 3-propylaminated CPGs that yield highly efficient Ln-extracting materials with distribution coefficients exceeding 10000 mL/g. The resulting Ln complexes were studied using X-ray absorption, magnetic resonance, and time-resolved luminescence spectroscopies. One of these CPG materials involving an imidodi(methanediphosphate) moiety demonstrated high extraction efficacy, significant ionic radius sensitivity, and exceptional tolerance to masking agents, which is conducive to its use for removal of traces of radionuclide ions from aqueous TALSPEAK raffinate (trivalent actinide−lanthanide separation by phosphorus reagent extraction from aqueous complexes process used in processing of spent nuclear fuel). The glass loaded with the extracted metal ions can be calcined and sintered at 1100 °C, yielding fused material that buries Ln ions in the vitreous matrix. This processing temperature is significantly lower than 1700 °C that is required for direct vitrification of lanthanide oxides in high-silica glass. X-ray absorption spectroscopy and acid leaching tests indicate that the immobilized ions are isolated and dispersed in the fused glass matrix. Thus, the method integrates Ln ions into the glass network. The resulting glass can be used for temporary storage or as the source of silica for production of borosilicate waste forms that are used for long-term disposal of high level radioactive waste. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102494r Exemplaires
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Titre : Effect of change in fluidizing gas on riser hydrodynamics and evaluation of scaling laws Type de document : texte imprimé Auteurs : Naoko Ellis, Auteur ; Min Xu, Auteur ; C. Jim Lim, Auteur Année de publication : 2011 Article en page(s) : pp. 4697–4706 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Fluidizing Gas Résumé : Riser hydrodynamics in a circulating fluidized bed are investigated experimentally and numerically by changing the composition of the fluidizing gas. Helium gas is added to air in the range of 0 to 96 vol % for fluidizing FCC particles 78 μm in size and density of 1560 kg/m3. Increasing He concentration decreases the fluidizing gas density and viscosity. The effect of change in gas composition is measured through the change in voidage along the riser from the pressure drop and the solids circulation rate, while analyzed by changes in slip velocity and particle Reynolds number. Numerical simulations using Computational Fluid Dynamics (CFD) have successfully predicted the experimental measurements over the entire range of fluidizing gas densities investigated. Simulations have also revealed that interphase momentum exchange in the bottom, accelerated region of the riser is dominated by cluster formation, while individual particle drag was dominant in the upper, more dilute regions. Given that CFD simulations have successfully reproduced these results, a scaling scheme is investigated whereby a hot model unit is simulated keeping either the Archimedes number or the density ratio of particle to gas constant. The results indicated better agreement between experimental and numerical voidage profiles for the density ratio scaling. Using the full set of scaling laws produced excellent prediction of the upper, fully developed region of the riser, but failed in the bottom regions. The scaling error in the bottom region was attributed to the momentum interaction in this region being dominated by cluster formation and not by the drag force on individual particles for which the scaling laws were derived. CFD has shown to be an effective tool in evaluation of scaling laws in risers. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101141f
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4697–4706[article] Effect of change in fluidizing gas on riser hydrodynamics and evaluation of scaling laws [texte imprimé] / Naoko Ellis, Auteur ; Min Xu, Auteur ; C. Jim Lim, Auteur . - 2011 . - pp. 4697–4706.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4697–4706
Mots-clés : Fluidizing Gas Résumé : Riser hydrodynamics in a circulating fluidized bed are investigated experimentally and numerically by changing the composition of the fluidizing gas. Helium gas is added to air in the range of 0 to 96 vol % for fluidizing FCC particles 78 μm in size and density of 1560 kg/m3. Increasing He concentration decreases the fluidizing gas density and viscosity. The effect of change in gas composition is measured through the change in voidage along the riser from the pressure drop and the solids circulation rate, while analyzed by changes in slip velocity and particle Reynolds number. Numerical simulations using Computational Fluid Dynamics (CFD) have successfully predicted the experimental measurements over the entire range of fluidizing gas densities investigated. Simulations have also revealed that interphase momentum exchange in the bottom, accelerated region of the riser is dominated by cluster formation, while individual particle drag was dominant in the upper, more dilute regions. Given that CFD simulations have successfully reproduced these results, a scaling scheme is investigated whereby a hot model unit is simulated keeping either the Archimedes number or the density ratio of particle to gas constant. The results indicated better agreement between experimental and numerical voidage profiles for the density ratio scaling. Using the full set of scaling laws produced excellent prediction of the upper, fully developed region of the riser, but failed in the bottom regions. The scaling error in the bottom region was attributed to the momentum interaction in this region being dominated by cluster formation and not by the drag force on individual particles for which the scaling laws were derived. CFD has shown to be an effective tool in evaluation of scaling laws in risers. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101141f Exemplaires
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Titre : Visualization and measurement of CO2 flooding in porous media using MRI Type de document : texte imprimé Auteurs : Yuechao Zhao, Auteur ; Yongchen Song, Auteur ; Yu Liu, Auteur Année de publication : 2011 Article en page(s) : pp. 4707–4715 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : CO2 Porous media Résumé : CO2 flooding is used extensively as a commercial process for enhanced oil recovery. In this study, the visualization of CO2 flooding in immiscible and miscible displacements in a high-pressure condition was studied using a 400 MHz MRI system. For CO2 immiscible displacement, the phenomenon of CO2 channelling or fingering was obviously due to the difference in fluid viscosities and densities. Thus, the sweep efficiency was small, and the final residual oil saturation was 37.2%. For CO2 miscible displacement, the results showed that pistonlike displacement occurred, and the phenomenon of the miscible regions and CO2 front was obvious. The viscous fingering and gravity override caused by the low viscosity and density of the gas were restrained effectively, and the velocity of the CO2 front was uniform. The sweep efficiency was high, and the final residual oil saturation was 13.5%, indicating that CO2 miscible displacement could recover more oil compared with CO2 immiscible displacement. Finally, the average velocity of the CO2 front was evaluated by analyzing the oil saturation profile. A special core analysis method was applied to in situ oil saturation data to directly evaluate the effect of viscosity, buoyancy, and capillary pressure on CO2 miscible displacement. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1013019
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4707–4715[article] Visualization and measurement of CO2 flooding in porous media using MRI [texte imprimé] / Yuechao Zhao, Auteur ; Yongchen Song, Auteur ; Yu Liu, Auteur . - 2011 . - pp. 4707–4715.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4707–4715
Mots-clés : CO2 Porous media Résumé : CO2 flooding is used extensively as a commercial process for enhanced oil recovery. In this study, the visualization of CO2 flooding in immiscible and miscible displacements in a high-pressure condition was studied using a 400 MHz MRI system. For CO2 immiscible displacement, the phenomenon of CO2 channelling or fingering was obviously due to the difference in fluid viscosities and densities. Thus, the sweep efficiency was small, and the final residual oil saturation was 37.2%. For CO2 miscible displacement, the results showed that pistonlike displacement occurred, and the phenomenon of the miscible regions and CO2 front was obvious. The viscous fingering and gravity override caused by the low viscosity and density of the gas were restrained effectively, and the velocity of the CO2 front was uniform. The sweep efficiency was high, and the final residual oil saturation was 13.5%, indicating that CO2 miscible displacement could recover more oil compared with CO2 immiscible displacement. Finally, the average velocity of the CO2 front was evaluated by analyzing the oil saturation profile. A special core analysis method was applied to in situ oil saturation data to directly evaluate the effect of viscosity, buoyancy, and capillary pressure on CO2 miscible displacement. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1013019 Exemplaires
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Titre : CO2 Capture and Hydrogen Production in an Integrated Fluidized Bed Reformer-Regenerator System Type de document : texte imprimé Auteurs : Zhongxiang Chen, Auteur ; John R. Grace, Auteur ; C. Jim Lim, Auteur Année de publication : 2011 Article en page(s) : pp. 4716–4721 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : CO2 capture hydrogen Regenerator system Résumé : Thermodynamic analysis of CO2 capture and hydrogen production for steam methane reforming was carried out using ASPEN simulation software. The integrated reaction system is composed of a sorbent-enhanced fluidized bed reformer coupled with a fluidized bed sorbent regenerator (calciner) where fine CaO-based sorbents (100 μm mean particle diameter) were used. The system performance is evaluated as a function of a number of operating parameters for both the reformer and regenerator. The results indicate that the optimum operating parameters for reformer are temperatures from 550 to 600 °C, low pressure, steam-to-carbon molar feed ratio of 3.5, and sorbent circulation flow rate exceeding the minimum stoichiometric feed rate of active sorbent. For the sorbent regenerator, the optimum conditions are temperatures above 850 °C, low pressure, and enough sweep gas flow to completely calcine CaCO3. On the basis of thermodynamics, it should be possible to achieve a hydrogen purity of 98% and a CO2 purity in excess of 99% after condensing sweep steam downstream. The predicted hydrogen purity is consistent with previous experiments. The high-concentration CO2 should be suitable for sequestration or for industrial use. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101360x
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4716–4721[article] CO2 Capture and Hydrogen Production in an Integrated Fluidized Bed Reformer-Regenerator System [texte imprimé] / Zhongxiang Chen, Auteur ; John R. Grace, Auteur ; C. Jim Lim, Auteur . - 2011 . - pp. 4716–4721.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4716–4721
Mots-clés : CO2 capture hydrogen Regenerator system Résumé : Thermodynamic analysis of CO2 capture and hydrogen production for steam methane reforming was carried out using ASPEN simulation software. The integrated reaction system is composed of a sorbent-enhanced fluidized bed reformer coupled with a fluidized bed sorbent regenerator (calciner) where fine CaO-based sorbents (100 μm mean particle diameter) were used. The system performance is evaluated as a function of a number of operating parameters for both the reformer and regenerator. The results indicate that the optimum operating parameters for reformer are temperatures from 550 to 600 °C, low pressure, steam-to-carbon molar feed ratio of 3.5, and sorbent circulation flow rate exceeding the minimum stoichiometric feed rate of active sorbent. For the sorbent regenerator, the optimum conditions are temperatures above 850 °C, low pressure, and enough sweep gas flow to completely calcine CaCO3. On the basis of thermodynamics, it should be possible to achieve a hydrogen purity of 98% and a CO2 purity in excess of 99% after condensing sweep steam downstream. The predicted hydrogen purity is consistent with previous experiments. The high-concentration CO2 should be suitable for sequestration or for industrial use. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101360x Exemplaires
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Titre : Gas hydrate formation in carbon dioxide + nitrogen + water system : compositional analysis of equilibrium phases Type de document : texte imprimé Auteurs : Veronica Belandria, Auteur ; Ali Eslamimanesh, Auteur ; Amir H. Mohammadi, Auteur Année de publication : 2011 Article en page(s) : pp. 4722–4730 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Gas Analysis equilibrium phases Résumé : In this Article, experimental data on compositions of equilibrium phases under gas hydrate formation conditions are reported for the carbon dioxide + nitrogen + water system in the (273.6 to 281.7) K temperature range for pressures up to 17.628 MPa. An experimental “in-house” setup based on the “static-analytic” technique was employed for performing the measurements. An isochoric pressure-search method in combination with gas phase compositional analysis was used to measure compositions of the gas phase in equilibrium with gas hydrate and liquid water. A material balance method was used to determine compositions of the hydrate and aqueous phases. A mathematical approach based on the Newton’s numerical method and the Differential Evolution optimization strategy was applied to solve the material balance equations. The compositional data generated in this work are compared with the corresponding experimental data reported in the literature as well as the predictions of the CSMGem thermodynamic model. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101635k
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4722–4730[article] Gas hydrate formation in carbon dioxide + nitrogen + water system : compositional analysis of equilibrium phases [texte imprimé] / Veronica Belandria, Auteur ; Ali Eslamimanesh, Auteur ; Amir H. Mohammadi, Auteur . - 2011 . - pp. 4722–4730.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4722–4730
Mots-clés : Gas Analysis equilibrium phases Résumé : In this Article, experimental data on compositions of equilibrium phases under gas hydrate formation conditions are reported for the carbon dioxide + nitrogen + water system in the (273.6 to 281.7) K temperature range for pressures up to 17.628 MPa. An experimental “in-house” setup based on the “static-analytic” technique was employed for performing the measurements. An isochoric pressure-search method in combination with gas phase compositional analysis was used to measure compositions of the gas phase in equilibrium with gas hydrate and liquid water. A material balance method was used to determine compositions of the hydrate and aqueous phases. A mathematical approach based on the Newton’s numerical method and the Differential Evolution optimization strategy was applied to solve the material balance equations. The compositional data generated in this work are compared with the corresponding experimental data reported in the literature as well as the predictions of the CSMGem thermodynamic model. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101635k Exemplaires
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Titre : Wax solubility in gaseous system : thermodynamic consistency test of experimental data Type de document : texte imprimé Auteurs : Amir H. Mohammadi, Auteur ; Ali Eslamimanesh, Auteur ; Dominique Richon, Auteur Année de publication : 2011 Article en page(s) : pp. 4731–4740 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Gaseous system Thermodynamic Résumé : Wax deposition from natural gas can cause severe problems in production, transmission and processing operations. Accurate knowledge of wax solubility in natural gas system is required to avoid operating problems. Unfortunately, experimental measurements of solubilities of these compounds in gaseous systems are quite challenging. This is partly because concentrations of these solid substances in the gas phase are extremely low; this generally may result in generation of highly uncertain experimental data. In this paper, we present a thermodynamic consistency test based on the Gibbs−Duhem equation to determine the reliability of experimental solubility data of paraffin waxes (n-C24H50 to n-C33H68) available in the open literature. This test uses the Peng−Robinson equation of state and two-fluid van der Waals (vdW2) mixing rules to represent the solubilities of solid waxy compounds in supercritical CO2 and ethane. The results show that all the investigated experimental data that are well represented by the applied thermodynamic model seem to be thermodynamically consistent. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1022145
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4731–4740[article] Wax solubility in gaseous system : thermodynamic consistency test of experimental data [texte imprimé] / Amir H. Mohammadi, Auteur ; Ali Eslamimanesh, Auteur ; Dominique Richon, Auteur . - 2011 . - pp. 4731–4740.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4731–4740
Mots-clés : Gaseous system Thermodynamic Résumé : Wax deposition from natural gas can cause severe problems in production, transmission and processing operations. Accurate knowledge of wax solubility in natural gas system is required to avoid operating problems. Unfortunately, experimental measurements of solubilities of these compounds in gaseous systems are quite challenging. This is partly because concentrations of these solid substances in the gas phase are extremely low; this generally may result in generation of highly uncertain experimental data. In this paper, we present a thermodynamic consistency test based on the Gibbs−Duhem equation to determine the reliability of experimental solubility data of paraffin waxes (n-C24H50 to n-C33H68) available in the open literature. This test uses the Peng−Robinson equation of state and two-fluid van der Waals (vdW2) mixing rules to represent the solubilities of solid waxy compounds in supercritical CO2 and ethane. The results show that all the investigated experimental data that are well represented by the applied thermodynamic model seem to be thermodynamically consistent. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1022145 Exemplaires
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Titre : Gas - solid fluidization in mini- and micro-channels Type de document : texte imprimé Auteurs : Fei Wang, Auteur ; Liang-Shih Fan, Auteur Année de publication : 2011 Article en page(s) : pp. 4741–4751 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Gas solid fluidization Résumé : Much of the fundamental research reported in the literature on gas−solid fluidization properties has been performed with large gas−solid fluidized beds. However, little is known regarding gas−solid fluidization in the mini- and microscale channel sizes ranging from 10−3 to 10−2 m and 10−5 to 10−4 m, respectively. The wall effects in the mini- and microchannels significantly affect the hydrodynamics of gas−solid fluidization. Such effects are examined experimentally in this study using FCC particles in six mini- and microchannels with sizes ranging from 700 μm to 5 mm. The data reveal a significant increase in the minimum fluidization and bubbling velocities as well as the wall friction in the mini- and microchannels compared to those in large fluidized beds. Additionally, the maximum stable bubble size increases with the superficial gas velocity and channel size. The round-nosed slug and the wall slug are observed in the channels. Correlations for predicting the fluidization regime transition in large fluidized beds are not adequate for predicting that in the mini- and microchannels. Also, differing from fluidization in a large bed, there is regime transition instability in that particulate fluidization is observed to form in the 700 μm and 1 mm channels through the bubbling/slugging transition as the gas velocity increases beyond that for the fixed bed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102245m
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4741–4751[article] Gas - solid fluidization in mini- and micro-channels [texte imprimé] / Fei Wang, Auteur ; Liang-Shih Fan, Auteur . - 2011 . - pp. 4741–4751.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4741–4751
Mots-clés : Gas solid fluidization Résumé : Much of the fundamental research reported in the literature on gas−solid fluidization properties has been performed with large gas−solid fluidized beds. However, little is known regarding gas−solid fluidization in the mini- and microscale channel sizes ranging from 10−3 to 10−2 m and 10−5 to 10−4 m, respectively. The wall effects in the mini- and microchannels significantly affect the hydrodynamics of gas−solid fluidization. Such effects are examined experimentally in this study using FCC particles in six mini- and microchannels with sizes ranging from 700 μm to 5 mm. The data reveal a significant increase in the minimum fluidization and bubbling velocities as well as the wall friction in the mini- and microchannels compared to those in large fluidized beds. Additionally, the maximum stable bubble size increases with the superficial gas velocity and channel size. The round-nosed slug and the wall slug are observed in the channels. Correlations for predicting the fluidization regime transition in large fluidized beds are not adequate for predicting that in the mini- and microchannels. Also, differing from fluidization in a large bed, there is regime transition instability in that particulate fluidization is observed to form in the 700 μm and 1 mm channels through the bubbling/slugging transition as the gas velocity increases beyond that for the fixed bed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102245m Exemplaires
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Titre : Thermodynamics of partitioning system with dimerization taking place in both phases Type de document : texte imprimé Auteurs : Bingwen Long, Auteur ; Yiheng Luo, Auteur Année de publication : 2011 Article en page(s) : pp. 4752–4760 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Thermodynamics Résumé : The partition coefficients of benzoic acid in partially miscible two phase mixtures of (methanol + cyclohexane) were measured at the temperature of 293.15, 303.15, and 313.15 K. The experimental results show that the benzoic acid is more soluble in methanol than in cyclohexane and thus it makes the partition coefficients, defined as the ratio of the total molar concentration of benzoic acid in methanol phase to cyclohexane phase, be greater than unity. In addition, the partition coefficient at each temperature is not a constant but increases with the increase of benzoic acid concentration in each phase even at very low concentration. This seeming deviation to the Nernst law can be explained by chemical theory of strong dimerization reactions taking place in both phases. Accordingly, a new generalized equilibrium model was proposed to describe the partition system with solute self-dimerization in both phases. The new model predictions agree well with the experimental data and the equilibrium constants for all the proposed association and partition reactions are obtained simultaneously by fitting the experimental data with nonlinear least-squares method. The results show that there is much stronger dimerization reaction for benzoic acid in methanol phase than in cycolhexane phase, which results in that the dimerization in cycolhexane phases can be totally neglected. In the methanol phase alone, the calculation results further show that dimerization of benzoic acid is so strong that almost all the solute molecules form dimers within the concentration investigated. The standard thermodynamics functions of Gibbs energy, enthalpy and entropy changes for the proposed reactions were estimated with the obtained parameters at different temperature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1022964
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4752–4760[article] Thermodynamics of partitioning system with dimerization taking place in both phases [texte imprimé] / Bingwen Long, Auteur ; Yiheng Luo, Auteur . - 2011 . - pp. 4752–4760.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4752–4760
Mots-clés : Thermodynamics Résumé : The partition coefficients of benzoic acid in partially miscible two phase mixtures of (methanol + cyclohexane) were measured at the temperature of 293.15, 303.15, and 313.15 K. The experimental results show that the benzoic acid is more soluble in methanol than in cyclohexane and thus it makes the partition coefficients, defined as the ratio of the total molar concentration of benzoic acid in methanol phase to cyclohexane phase, be greater than unity. In addition, the partition coefficient at each temperature is not a constant but increases with the increase of benzoic acid concentration in each phase even at very low concentration. This seeming deviation to the Nernst law can be explained by chemical theory of strong dimerization reactions taking place in both phases. Accordingly, a new generalized equilibrium model was proposed to describe the partition system with solute self-dimerization in both phases. The new model predictions agree well with the experimental data and the equilibrium constants for all the proposed association and partition reactions are obtained simultaneously by fitting the experimental data with nonlinear least-squares method. The results show that there is much stronger dimerization reaction for benzoic acid in methanol phase than in cycolhexane phase, which results in that the dimerization in cycolhexane phases can be totally neglected. In the methanol phase alone, the calculation results further show that dimerization of benzoic acid is so strong that almost all the solute molecules form dimers within the concentration investigated. The standard thermodynamics functions of Gibbs energy, enthalpy and entropy changes for the proposed reactions were estimated with the obtained parameters at different temperature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1022964 Exemplaires
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Titre : Experimental measurement of vapor pressures and densities at saturation of pure hexafluoropropylene oxide : modeling using a crossover equation of state Type de document : texte imprimé Auteurs : Moussa Dicko, Auteur ; Ghemina Belaribi-Boukais, Auteur ; Christophe Coquelet, Auteur Année de publication : 2011 Article en page(s) : pp. 4761–4768 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Vapor pressures Oxide Hexafluoropropylene Résumé : Hydrofluoroalkenes, like hexafluoropropylene, can be considered as new working fluids for refrigeration systems and consequently volumetric and critical property data are required. In this study, a vibrating tube densitometer technique was used to determine densities at nine different temperatures between (263 and 358) K, and pressures between (0.04 and 15) MPa. The experimental uncertainties are ±0.0003 and ±0.0006 MPa for pressure, ± 0.02 K for temperature, ± 0.5% (relative) for vapor densities, and ±0.05% for liquid densities. A different equipment based on static method is used for the determination of pure component vapor pressures for temperatures between (231 and 359) K. The experimental uncertainties are ±0.0005 MPa for pressure and ±0.02 K for the temperature. Critical properties have been determined by direct measurement and also from utilization of experimental densities considering the asymptotic scaling law behavior. The Patel−Teja and crossover Patel−Teja equations of state are used to correlate the data. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102354p
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4761–4768[article] Experimental measurement of vapor pressures and densities at saturation of pure hexafluoropropylene oxide : modeling using a crossover equation of state [texte imprimé] / Moussa Dicko, Auteur ; Ghemina Belaribi-Boukais, Auteur ; Christophe Coquelet, Auteur . - 2011 . - pp. 4761–4768.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4761–4768
Mots-clés : Vapor pressures Oxide Hexafluoropropylene Résumé : Hydrofluoroalkenes, like hexafluoropropylene, can be considered as new working fluids for refrigeration systems and consequently volumetric and critical property data are required. In this study, a vibrating tube densitometer technique was used to determine densities at nine different temperatures between (263 and 358) K, and pressures between (0.04 and 15) MPa. The experimental uncertainties are ±0.0003 and ±0.0006 MPa for pressure, ± 0.02 K for temperature, ± 0.5% (relative) for vapor densities, and ±0.05% for liquid densities. A different equipment based on static method is used for the determination of pure component vapor pressures for temperatures between (231 and 359) K. The experimental uncertainties are ±0.0005 MPa for pressure and ±0.02 K for the temperature. Critical properties have been determined by direct measurement and also from utilization of experimental densities considering the asymptotic scaling law behavior. The Patel−Teja and crossover Patel−Teja equations of state are used to correlate the data. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102354p Exemplaires
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Titre : Numerical assessment of hydrodynamic cavitation reactors using organic solvents Type de document : texte imprimé Auteurs : Peeush Kumar, Auteur ; V. S. Moholkar, Auteur Année de publication : 2011 Article en page(s) : pp 4769–4775 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydrodynamic cavitation Organic solvents Résumé : This paper attempts to give a physical insight into the behavior of cavitation bubbles in a hydrodynamic cavitation reactor, with organic liquids employed as the bulk medium. The diffusion limited model of cavitation bubble dynamics has been coupled to hydrodynamics of flow through an orifice. Two kinds of bubbles, namely, air and argon, and two organic liquids, namely, n-hexane and toluene, have been chosen as the model system. The effect of four parameters on the dynamics of cavitation bubbles, namely, cavitation number, orifice to pipe diameter ratio, downstream recovery pressure, and initial bubble radius, has been investigated. Simulations show interesting results that dynamics of cavitation bubbles in organic media is relatively insensitive to operating parameters. These results have been attributed to physical properties of the organic media. Relatively, the intensity of the collapse of bubbles in toluene is higher than in hexane; however, the temperature peaks attained at the transient collapse of bubbles in both liquids are too low to allow formation of radical species in appreciable quantities. Hydrodynamic cavitation reactors with organic media are unsuitable for sonochemical reactions, although some physical processes or chemical reactions with external addition of source of radicals/ions may well be carried out. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1025024
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp 4769–4775[article] Numerical assessment of hydrodynamic cavitation reactors using organic solvents [texte imprimé] / Peeush Kumar, Auteur ; V. S. Moholkar, Auteur . - 2011 . - pp 4769–4775.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp 4769–4775
Mots-clés : Hydrodynamic cavitation Organic solvents Résumé : This paper attempts to give a physical insight into the behavior of cavitation bubbles in a hydrodynamic cavitation reactor, with organic liquids employed as the bulk medium. The diffusion limited model of cavitation bubble dynamics has been coupled to hydrodynamics of flow through an orifice. Two kinds of bubbles, namely, air and argon, and two organic liquids, namely, n-hexane and toluene, have been chosen as the model system. The effect of four parameters on the dynamics of cavitation bubbles, namely, cavitation number, orifice to pipe diameter ratio, downstream recovery pressure, and initial bubble radius, has been investigated. Simulations show interesting results that dynamics of cavitation bubbles in organic media is relatively insensitive to operating parameters. These results have been attributed to physical properties of the organic media. Relatively, the intensity of the collapse of bubbles in toluene is higher than in hexane; however, the temperature peaks attained at the transient collapse of bubbles in both liquids are too low to allow formation of radical species in appreciable quantities. Hydrodynamic cavitation reactors with organic media are unsuitable for sonochemical reactions, although some physical processes or chemical reactions with external addition of source of radicals/ions may well be carried out. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1025024 Exemplaires
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Titre : Multicomponent maxwell−stefan diffusivities at infinite dilution Type de document : texte imprimé Auteurs : Xin Liu, Auteur ; Andre Bardow, Auteur ; Thijs J.H. Vlugt, Auteur Année de publication : 2011 Article en page(s) : pp. 4776–4782 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Chemical processes Résumé : Diffusion plays an important role in (bio)chemical processes. It is usually difficult to obtain Maxwell−Stefan diffusivities from experiments as well as molecular simulation. Therefore, predictive models based on easily measurable quantities are highly desired. The Vignes equation is commonly used to describe the concentration dependence of Maxwell−Stefan diffusivities. In mixtures containing at least three components, the generalized Vignes equation requires the value of the quantity Đijxk→1, which describes the friction between components i and j when both are infinitely diluted in component k. Over the past decades, several empirical models were proposed for estimating Đijxk→1, and all of these are lacking a sound theoretical basis. In this study, we show that Đijxk→1 actually exists (i.e., its value does not depend on the molar ratio xi/xj), and we derive an analytical expression for Đijxk→1 that is based on the linear response theory and the Onsager relations. We find that Đijxk→1 can be expressed in terms of binary and pure-component self-diffusivities and integrals over velocity cross-correlation functions. By neglecting the latter terms, we obtain a convenient predictive model for Đijxk→1. Molecular dynamics simulations are used to validate the assumptions made in this model. The following test systems are considered: a ternary system consisting of particles interacting using Weeks−Chandler−Andersen (WCA) interactions and the ternary systems n-hexane−cyclohexane−toluene and ethanol−methanol−water. Our results show that (1) for the WCA system, as well as the n-hexane−cyclohexane−toluene system, neglecting the integrals over velocity cross-correlation functions results in accurate predictions for Đijxk→1; (2) for the WCA system, our model prediction is superior, compared to the existing models for Đijxk→1; (3) in the ethanol−methanol−water system, the integrals over velocity cross-correlation functions cannot be neglected, because of the presence of hydrogen bonds (models for predicting Đijxk→1 in this system will require detailed information on the collective motion of molecules); and (4) our model may provide an explanation why the Maxwell−Stefan diffusivity describing the friction between adsorbed components in a porous material is usually very large. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102515w
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4776–4782[article] Multicomponent maxwell−stefan diffusivities at infinite dilution [texte imprimé] / Xin Liu, Auteur ; Andre Bardow, Auteur ; Thijs J.H. Vlugt, Auteur . - 2011 . - pp. 4776–4782.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4776–4782
Mots-clés : Chemical processes Résumé : Diffusion plays an important role in (bio)chemical processes. It is usually difficult to obtain Maxwell−Stefan diffusivities from experiments as well as molecular simulation. Therefore, predictive models based on easily measurable quantities are highly desired. The Vignes equation is commonly used to describe the concentration dependence of Maxwell−Stefan diffusivities. In mixtures containing at least three components, the generalized Vignes equation requires the value of the quantity Đijxk→1, which describes the friction between components i and j when both are infinitely diluted in component k. Over the past decades, several empirical models were proposed for estimating Đijxk→1, and all of these are lacking a sound theoretical basis. In this study, we show that Đijxk→1 actually exists (i.e., its value does not depend on the molar ratio xi/xj), and we derive an analytical expression for Đijxk→1 that is based on the linear response theory and the Onsager relations. We find that Đijxk→1 can be expressed in terms of binary and pure-component self-diffusivities and integrals over velocity cross-correlation functions. By neglecting the latter terms, we obtain a convenient predictive model for Đijxk→1. Molecular dynamics simulations are used to validate the assumptions made in this model. The following test systems are considered: a ternary system consisting of particles interacting using Weeks−Chandler−Andersen (WCA) interactions and the ternary systems n-hexane−cyclohexane−toluene and ethanol−methanol−water. Our results show that (1) for the WCA system, as well as the n-hexane−cyclohexane−toluene system, neglecting the integrals over velocity cross-correlation functions results in accurate predictions for Đijxk→1; (2) for the WCA system, our model prediction is superior, compared to the existing models for Đijxk→1; (3) in the ethanol−methanol−water system, the integrals over velocity cross-correlation functions cannot be neglected, because of the presence of hydrogen bonds (models for predicting Đijxk→1 in this system will require detailed information on the collective motion of molecules); and (4) our model may provide an explanation why the Maxwell−Stefan diffusivity describing the friction between adsorbed components in a porous material is usually very large. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102515w Exemplaires
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Titre : Evaluation of a tert - butyl peroxybenzoate runaway reaction by five kinetic models Type de document : texte imprimé Auteurs : Jo-Ming Tseng, Auteur Année de publication : 2011 Article en page(s) : pp. 4783–4787 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetic Résumé : This study focuses on understanding the basic kinetic parameters associated with runaway reactions for tert-butyl peroxybenzoate (TBPB), which is a strong free-radical source. TBPB is used as a polymerization initiator, catalyst, vulcanizing agent, cross-linking agent, and chemical intermediate. Runaway reactions can either be induced by hot spots or caused by insufficient heat removal. It is important to understand the decomposition reactions that may result in a runaway reaction. To do so, one must evaluate the thermal kinetic parameters, such as activation energy, frequency factor, and reaction order to make the process safer. Most investigations focus on methyl ethyl ketone peroxide, di-tert-butyl peroxide, and cumene hydroperoxide. The kinetic parameters indicate the degree of thermal hazard based on accidents triggered by TBPB. This study uses mathematical models of the Coats−Redfern equation, the Arrhenius equation, the corrected kinetic equation, the Kissinger equation, and the Ozawa equation to study these kinetic parameters. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100640t
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4783–4787[article] Evaluation of a tert - butyl peroxybenzoate runaway reaction by five kinetic models [texte imprimé] / Jo-Ming Tseng, Auteur . - 2011 . - pp. 4783–4787.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4783–4787
Mots-clés : Kinetic Résumé : This study focuses on understanding the basic kinetic parameters associated with runaway reactions for tert-butyl peroxybenzoate (TBPB), which is a strong free-radical source. TBPB is used as a polymerization initiator, catalyst, vulcanizing agent, cross-linking agent, and chemical intermediate. Runaway reactions can either be induced by hot spots or caused by insufficient heat removal. It is important to understand the decomposition reactions that may result in a runaway reaction. To do so, one must evaluate the thermal kinetic parameters, such as activation energy, frequency factor, and reaction order to make the process safer. Most investigations focus on methyl ethyl ketone peroxide, di-tert-butyl peroxide, and cumene hydroperoxide. The kinetic parameters indicate the degree of thermal hazard based on accidents triggered by TBPB. This study uses mathematical models of the Coats−Redfern equation, the Arrhenius equation, the corrected kinetic equation, the Kissinger equation, and the Ozawa equation to study these kinetic parameters. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100640t Exemplaires
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Titre : Heuristic design of reaction/separation processes with two recycles Type de document : texte imprimé Auteurs : William L. Luyben, Auteur Année de publication : 2011 Article en page(s) : pp. 4788–4795 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Separation Processes Résumé : A recent paper presented a heuristic approach to quickly estimate the optimum tradeoff between reactor size and recycle flow rate during the preliminary conceptual process design of a reaction/separation process. The basic idea is to find the minimum recycle flow rate by designing the process to meet some specified conversion/yield/selectivity criterion, using a very large reactor. A heuristic of setting the actual recycle flow rate equal to 1.2 times the minimum then is used to obtain an approximate optimum design. The process studied had relative volatilities such that only one recycle stream was needed. The purpose of this paper is to extend this work to the case where two recycle streams are required. There is a reactor and three distillation columns with two recycle streams. The desired product C is produced via the reaction A + B → C. An undesired product D is also produced. Two alternative reactions (A + C → D or A + B → D) mean that there is a large recycle of either B or A to achieve high selectivity. The relative volatilities are assumed to be αA > αC > αB > αD, so reactant A is recycled from the overhead of the first distillation column and reactant B is recycled from the overhead of the third column. Product C is the distillate of the second column, and product D is the bottoms of the third column. Results show that the more-complex separation section shifts the economics to favor a smaller heuristic ratio (1.05) of actual recycle to minimum recycle. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101896v
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4788–4795[article] Heuristic design of reaction/separation processes with two recycles [texte imprimé] / William L. Luyben, Auteur . - 2011 . - pp. 4788–4795.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4788–4795
Mots-clés : Separation Processes Résumé : A recent paper presented a heuristic approach to quickly estimate the optimum tradeoff between reactor size and recycle flow rate during the preliminary conceptual process design of a reaction/separation process. The basic idea is to find the minimum recycle flow rate by designing the process to meet some specified conversion/yield/selectivity criterion, using a very large reactor. A heuristic of setting the actual recycle flow rate equal to 1.2 times the minimum then is used to obtain an approximate optimum design. The process studied had relative volatilities such that only one recycle stream was needed. The purpose of this paper is to extend this work to the case where two recycle streams are required. There is a reactor and three distillation columns with two recycle streams. The desired product C is produced via the reaction A + B → C. An undesired product D is also produced. Two alternative reactions (A + C → D or A + B → D) mean that there is a large recycle of either B or A to achieve high selectivity. The relative volatilities are assumed to be αA > αC > αB > αD, so reactant A is recycled from the overhead of the first distillation column and reactant B is recycled from the overhead of the third column. Product C is the distillate of the second column, and product D is the bottoms of the third column. Results show that the more-complex separation section shifts the economics to favor a smaller heuristic ratio (1.05) of actual recycle to minimum recycle. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101896v Exemplaires
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Titre : Simple method to evaluate and to predict flash points of organic compounds Type de document : texte imprimé Auteurs : Felix A. Carroll, Auteur ; Chung-Yon Lin, Auteur ; Frank H. Quina, Auteur Année de publication : 2011 Article en page(s) : pp. 4796–4800 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Organic compounds Résumé : Flash points (TFP) of organic compounds are calculated from their flash point numbers, NFP, with the relationship TFP = 23.369NFP2/3 + 20.010NFP1/3 + 31.901. In turn, the NFP values can be predicted from boiling point numbers (YBP) and functional group counts with the equation NFP = 0.974YBP + ∑i niGi + 0.095 where Gi is a functional group-specific contribution to the value of NFP and ni is the number of such functional groups in the structure. For a data set consisting of 1000 diverse organic compounds, the average absolute deviation between reported and predicted flash points was less than 2.5 K. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1021283
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4796–4800[article] Simple method to evaluate and to predict flash points of organic compounds [texte imprimé] / Felix A. Carroll, Auteur ; Chung-Yon Lin, Auteur ; Frank H. Quina, Auteur . - 2011 . - pp. 4796–4800.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4796–4800
Mots-clés : Organic compounds Résumé : Flash points (TFP) of organic compounds are calculated from their flash point numbers, NFP, with the relationship TFP = 23.369NFP2/3 + 20.010NFP1/3 + 31.901. In turn, the NFP values can be predicted from boiling point numbers (YBP) and functional group counts with the equation NFP = 0.974YBP + ∑i niGi + 0.095 where Gi is a functional group-specific contribution to the value of NFP and ni is the number of such functional groups in the structure. For a data set consisting of 1000 diverse organic compounds, the average absolute deviation between reported and predicted flash points was less than 2.5 K. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1021283 Exemplaires
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