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Vol. 49 N° 24 - Décembre 2010 [texte imprimé] . - 2011 . - p. 12333-12798 : ill. ; 28 cm. Chemical engineering Langues : Anglais (eng)
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Ajouter le résultat dans votre panierNew catalysts for the borohydride dyeing process / N. Meksi in Industrial & engineering chemistry research, Vol. 49 N° 24 (Décembre 2010)
Titre : New catalysts for the borohydride dyeing process Type de document : texte imprimé Auteurs : N. Meksi, Auteur ; M. Ben Ticha, Auteur ; M. Kechida, Auteur Année de publication : 2011 Article en page(s) : pp. 12333-12338 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalyst Résumé : In the borohydride dyeing process, indigo cannot be reduced by sodium borohydride to its reduced form without the addition of catalyst. This catalyst, which is a metallic salt, is used to activate the reduction procedure of the reducing agent. So, the reduction reaction of indigo depends significantly on the nature of this catalyst. In this paper, the effect of 12 different metallic salts on the performances of the indigo reduction reaction has been discussed. These performances were evaluated by measuring the indigo reduction yield as well as the color yield (K/S) of the dyed samples of cotton. In these studies, it was found that the copper-based catalysts were the best and offered maximum performance. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23691983
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12333-12338[article] New catalysts for the borohydride dyeing process [texte imprimé] / N. Meksi, Auteur ; M. Ben Ticha, Auteur ; M. Kechida, Auteur . - 2011 . - pp. 12333-12338.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12333-12338
Mots-clés : Catalyst Résumé : In the borohydride dyeing process, indigo cannot be reduced by sodium borohydride to its reduced form without the addition of catalyst. This catalyst, which is a metallic salt, is used to activate the reduction procedure of the reducing agent. So, the reduction reaction of indigo depends significantly on the nature of this catalyst. In this paper, the effect of 12 different metallic salts on the performances of the indigo reduction reaction has been discussed. These performances were evaluated by measuring the indigo reduction yield as well as the color yield (K/S) of the dyed samples of cotton. In these studies, it was found that the copper-based catalysts were the best and offered maximum performance. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23691983 Exemplaires
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Titre : Design and analysis of experiments for obtaining high bulk density sodium tripolyphosphate Type de document : texte imprimé Auteurs : Marcin Banach, Auteur ; Zygmunt Kowalski, Auteur Année de publication : 2011 Article en page(s) : pp. 12339-12344 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Bulk density Design Résumé : The results of experiments for obtaining granulated sodium tripolyphosphate with bulk density adjustable within 1.00-1.05 kg/dm3 and expected content of STPP crystalline phases are presented. The scope of experiments included the identification of factors with statistically significant impacts on the study object and the estimation of response surface. Because of the application of the Plackett-Burman design, 15 input factors could be evaluated regarding their impact significance and insignificant factors could be eliminated. Moreover, the Hartley design enabled the determination of a response surface based on the general regression equation in the form of a second degree polynomial with double interactions. The input factor values, determined on the basis of the prediction profile and desirability function, were used to perform a series of experiments to achieve STPP expected bulk density within the range of 1.00-1.05 kg/dm3. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23691984
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12339-12344[article] Design and analysis of experiments for obtaining high bulk density sodium tripolyphosphate [texte imprimé] / Marcin Banach, Auteur ; Zygmunt Kowalski, Auteur . - 2011 . - pp. 12339-12344.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12339-12344
Mots-clés : Bulk density Design Résumé : The results of experiments for obtaining granulated sodium tripolyphosphate with bulk density adjustable within 1.00-1.05 kg/dm3 and expected content of STPP crystalline phases are presented. The scope of experiments included the identification of factors with statistically significant impacts on the study object and the estimation of response surface. Because of the application of the Plackett-Burman design, 15 input factors could be evaluated regarding their impact significance and insignificant factors could be eliminated. Moreover, the Hartley design enabled the determination of a response surface based on the general regression equation in the form of a second degree polynomial with double interactions. The input factor values, determined on the basis of the prediction profile and desirability function, were used to perform a series of experiments to achieve STPP expected bulk density within the range of 1.00-1.05 kg/dm3. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23691984 Exemplaires
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Titre : Y - Al2O3 modified with praseodymium : an application in the heterogeneous catalytic ozonation of succinic acid in aqueous solution Type de document : texte imprimé Auteurs : Zhiqiao He, Auteur ; Angliang Zhang, Auteur ; Shuang Song, Auteur Année de publication : 2011 Article en page(s) : pp.12345–12351 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalytic ozonation Succinic acid Aqueous solution Résumé : In an attempt to utilize ozone effectively, a series of praseodymium-modified γ-Al2O3 (Pr/Al2O3) was prepared via incipient wetness impregnation using Pr(NO3)3·6H2O as the precursor. The structure and properties of the catalysts were studied by X-ray diffraction (XRD) and the Brunauer−Emmett−Teller (BET) method. Catalytic activity was evaluated by monitoring the degradation of succinic acid (SA) in the presence of ozone. The praseodymium modification can effectively enhance the ozonation activity of γ-Al2O3 upon SA removal. Increasing the calcination temperature of Pr/Al2O3 is disadvantageous for the catalytic process, whereas increasing the load of praseodymium is helpful. After three successive cycles, the Pr/Al2O3 catalyst remained stable in the catalytic ozonation of SA. Overall, the initial degradation rate of SA, as well as the saturated adsorption capacity of SA, were found to have a linear relation to changes of the surface hydroxyl groups of the catalyst. On this basis, we conclude that the significant enhancement of SA degradation using Pr/Al2O3 as a catalyst should be because praseodymium, in the form of Pr6O11, promoted the formation of surface hydroxyl groups. Hence, the adsorption was increased, and the degradation rate of SA was enhanced. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101233h
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp.12345–12351[article] Y - Al2O3 modified with praseodymium : an application in the heterogeneous catalytic ozonation of succinic acid in aqueous solution [texte imprimé] / Zhiqiao He, Auteur ; Angliang Zhang, Auteur ; Shuang Song, Auteur . - 2011 . - pp.12345–12351.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp.12345–12351
Mots-clés : Catalytic ozonation Succinic acid Aqueous solution Résumé : In an attempt to utilize ozone effectively, a series of praseodymium-modified γ-Al2O3 (Pr/Al2O3) was prepared via incipient wetness impregnation using Pr(NO3)3·6H2O as the precursor. The structure and properties of the catalysts were studied by X-ray diffraction (XRD) and the Brunauer−Emmett−Teller (BET) method. Catalytic activity was evaluated by monitoring the degradation of succinic acid (SA) in the presence of ozone. The praseodymium modification can effectively enhance the ozonation activity of γ-Al2O3 upon SA removal. Increasing the calcination temperature of Pr/Al2O3 is disadvantageous for the catalytic process, whereas increasing the load of praseodymium is helpful. After three successive cycles, the Pr/Al2O3 catalyst remained stable in the catalytic ozonation of SA. Overall, the initial degradation rate of SA, as well as the saturated adsorption capacity of SA, were found to have a linear relation to changes of the surface hydroxyl groups of the catalyst. On this basis, we conclude that the significant enhancement of SA degradation using Pr/Al2O3 as a catalyst should be because praseodymium, in the form of Pr6O11, promoted the formation of surface hydroxyl groups. Hence, the adsorption was increased, and the degradation rate of SA was enhanced. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101233h Exemplaires
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Titre : Application of sulfonated carbon - based catalyst for reactive extraction of 1,3-propanediol from model fermentation mixture Type de document : texte imprimé Auteurs : Panatpong Boonoun, Auteur ; Navadol Laosiripojana, Auteur ; Chirakarn Muangnapoh, Auteur Année de publication : 2011 Article en page(s) : pp. 12352-12357 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Fermentation Modeling Catalyst Résumé : This study deals with the possibility of the application of a low-cost sulfonated carbon-based catalyst for reactive extraction to separate 1,3-propanediol (1,3-PDO) from a model solution of 1,3-PDO biologically derived from glycerol. The catalyst was synthesized by incomplete carbonization of naphthalene in sulfuric acid, and was demonstrated to be active for the acetalization of 1,3-PDO with acetaldehyde in aqueous solution. The performance of the reactive extraction process by using a sulfonated carbon-based catalyst was proven to be excellent based on the percent recovery rate of 1,3-PDO. These results along with those on the catalyst reactivity demonstrate that the carbon-based catalyst can be used to replace expensive commercial catalysts currently used such as Dowex 50-WX4-200 and Amberlite IR120. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23691986
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12352-12357[article] Application of sulfonated carbon - based catalyst for reactive extraction of 1,3-propanediol from model fermentation mixture [texte imprimé] / Panatpong Boonoun, Auteur ; Navadol Laosiripojana, Auteur ; Chirakarn Muangnapoh, Auteur . - 2011 . - pp. 12352-12357.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12352-12357
Mots-clés : Fermentation Modeling Catalyst Résumé : This study deals with the possibility of the application of a low-cost sulfonated carbon-based catalyst for reactive extraction to separate 1,3-propanediol (1,3-PDO) from a model solution of 1,3-PDO biologically derived from glycerol. The catalyst was synthesized by incomplete carbonization of naphthalene in sulfuric acid, and was demonstrated to be active for the acetalization of 1,3-PDO with acetaldehyde in aqueous solution. The performance of the reactive extraction process by using a sulfonated carbon-based catalyst was proven to be excellent based on the percent recovery rate of 1,3-PDO. These results along with those on the catalyst reactivity demonstrate that the carbon-based catalyst can be used to replace expensive commercial catalysts currently used such as Dowex 50-WX4-200 and Amberlite IR120. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23691986 Exemplaires
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Titre : Kinetic modeling of liquid phase photocatalysis on supported TiO2 nanoparticles in a rectangular flat - plate photoreactor Type de document : texte imprimé Auteurs : A. R. Khataee, Auteur ; M. Fathinia, Auteur ; S. Aber, Auteur Année de publication : 2011 Article en page(s) : pp. 12358-12364 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Modeling Photochemical reactor Flat plate Nanoparticle Titanium oxide Photocatalysis Liquid phase Kinetic model Résumé : The photocatalytic degradation of C.I. Basic Blue 3 (BB3) in water on supported TiO2 nanoparticles was carried out in a rectangular flat-plate photoreactor. The photocatalytic degradation kinetic characteristics were experimentally investigated under different light intensities and initial dye concentrations. Calculating corresponding "apparent adsorption constants", Ks, and "apparent rate constants", kr, of experimental results according to the Langmuir-Hinshelwood (L-H) model emphasized that the L-H constants varied with regard to the light intensity. A new kinetic model was developed on the basis of the intrinsic element reactions, which took into account the effect of light intensity, reaction intermediates, organic compound content, and first order reaction kinetics. The new kinetic model described the experimental results in a more accurate way and explained consistently the dependence of the apparent kinetic parameters kr and Ks on the light intensity. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23691987
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12358-12364[article] Kinetic modeling of liquid phase photocatalysis on supported TiO2 nanoparticles in a rectangular flat - plate photoreactor [texte imprimé] / A. R. Khataee, Auteur ; M. Fathinia, Auteur ; S. Aber, Auteur . - 2011 . - pp. 12358-12364.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12358-12364
Mots-clés : Modeling Photochemical reactor Flat plate Nanoparticle Titanium oxide Photocatalysis Liquid phase Kinetic model Résumé : The photocatalytic degradation of C.I. Basic Blue 3 (BB3) in water on supported TiO2 nanoparticles was carried out in a rectangular flat-plate photoreactor. The photocatalytic degradation kinetic characteristics were experimentally investigated under different light intensities and initial dye concentrations. Calculating corresponding "apparent adsorption constants", Ks, and "apparent rate constants", kr, of experimental results according to the Langmuir-Hinshelwood (L-H) model emphasized that the L-H constants varied with regard to the light intensity. A new kinetic model was developed on the basis of the intrinsic element reactions, which took into account the effect of light intensity, reaction intermediates, organic compound content, and first order reaction kinetics. The new kinetic model described the experimental results in a more accurate way and explained consistently the dependence of the apparent kinetic parameters kr and Ks on the light intensity. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23691987 Exemplaires
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Titre : Dehydrogenation of isopropanol on copper - containing mesoporous catalysts Type de document : texte imprimé Auteurs : Nancy F. Balsamo, Auteur ; Corina M. Chanquia, Auteur ; Eduardo R. Herrero, Auteur Année de publication : 2011 Article en page(s) : pp.12365–12370 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Mesoporous catalysts Résumé : Copper-containing mesoporous catalysts with an MCM-41 type structure have been prepared using direct hydrothermal synthesis and characterized using XRD, AAS, N2 adsorption−desorption, DRUV−vis, and TEM. All of the samples showed high structural regularity and surface area. Three copper species are presented in these materials: isolated mononuclear Cuδ+ species, oligonuclear [Cuδ+···Oδ−···Cuδ+]n clusters, and bulky CuO oxides. These materials were catalytically tested in isopropanol dehydrogenation, showing good activity and very high selectivity to propanone at 300 °C. A further reduction treatment of the samples allowed us to suggest possible active species. Both the [Cuδ+···Oδ−···Cuδ+]n clusters and the isolated Cuδ+ cations seem to be the species responsible for isopropanol dehydrogenation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100972h
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp.12365–12370[article] Dehydrogenation of isopropanol on copper - containing mesoporous catalysts [texte imprimé] / Nancy F. Balsamo, Auteur ; Corina M. Chanquia, Auteur ; Eduardo R. Herrero, Auteur . - 2011 . - pp.12365–12370.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp.12365–12370
Mots-clés : Mesoporous catalysts Résumé : Copper-containing mesoporous catalysts with an MCM-41 type structure have been prepared using direct hydrothermal synthesis and characterized using XRD, AAS, N2 adsorption−desorption, DRUV−vis, and TEM. All of the samples showed high structural regularity and surface area. Three copper species are presented in these materials: isolated mononuclear Cuδ+ species, oligonuclear [Cuδ+···Oδ−···Cuδ+]n clusters, and bulky CuO oxides. These materials were catalytically tested in isopropanol dehydrogenation, showing good activity and very high selectivity to propanone at 300 °C. A further reduction treatment of the samples allowed us to suggest possible active species. Both the [Cuδ+···Oδ−···Cuδ+]n clusters and the isolated Cuδ+ cations seem to be the species responsible for isopropanol dehydrogenation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100972h Exemplaires
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Titre : Kinetics of methanol transformation into hydrocarbons on a HZSM - 5 zeolite catalyst at high temperature (400 - 550 °C) Type de document : texte imprimé Auteurs : Andrés T. Aguayo, Auteur ; Diana Mier, Auteur ; Ana G. Gayubo, Auteur Année de publication : 2011 Article en page(s) : pp. 12371–12378 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetics Zeolite catalyst Résumé : A kinetic model of seven lumps has been established which allows the quantification of the product distribution (oxygenates, n-butane, C2−C4 olefins, C2−C4 paraffins (without n-butane), C5−C10 fraction, methane) in the transformation of methanol into hydrocarbons at high temperature (400−550 °C) on a HZSM-5 zeolite catalyst (SiO2/Al2O3 = 30) with high acidic strength (>120 kJ (mol of NH3)−1) and agglomerated with bentonite and alumina. The kinetic model fits well the experimental data obtained in a fixed bed reactor, from small values of space time in which the formation of hydrocarbons is incipient, to a space time of 2.4 (g of catalyst) h (mol CH2) −1 for a complete conversion of methanol. The rise in temperature increases the yield of C2−C4 olefins, so that the maximum value (50%) is obtained at the ceiling temperature for the hydrothermal stability of the HZSM-5 (550 °C) and space times between 0.6 and 1 (g of catalyst) h (mol CH2)−1. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101047f
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12371–12378[article] Kinetics of methanol transformation into hydrocarbons on a HZSM - 5 zeolite catalyst at high temperature (400 - 550 °C) [texte imprimé] / Andrés T. Aguayo, Auteur ; Diana Mier, Auteur ; Ana G. Gayubo, Auteur . - 2011 . - pp. 12371–12378.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12371–12378
Mots-clés : Kinetics Zeolite catalyst Résumé : A kinetic model of seven lumps has been established which allows the quantification of the product distribution (oxygenates, n-butane, C2−C4 olefins, C2−C4 paraffins (without n-butane), C5−C10 fraction, methane) in the transformation of methanol into hydrocarbons at high temperature (400−550 °C) on a HZSM-5 zeolite catalyst (SiO2/Al2O3 = 30) with high acidic strength (>120 kJ (mol of NH3)−1) and agglomerated with bentonite and alumina. The kinetic model fits well the experimental data obtained in a fixed bed reactor, from small values of space time in which the formation of hydrocarbons is incipient, to a space time of 2.4 (g of catalyst) h (mol CH2) −1 for a complete conversion of methanol. The rise in temperature increases the yield of C2−C4 olefins, so that the maximum value (50%) is obtained at the ceiling temperature for the hydrothermal stability of the HZSM-5 (550 °C) and space times between 0.6 and 1 (g of catalyst) h (mol CH2)−1. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101047f Exemplaires
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Titre : Investigation of the dissolution kinetics of meta - kaolin in H2SO4 solution Type de document : texte imprimé Auteurs : Mehmet Riza Altiokka, Auteur ; Handan Akalin, Auteur ; Nergis Melek, Auteur Année de publication : 2011 Article en page(s) : pp. 12379–12382 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : kinetics Résumé : Kaolin with a given size distribution was calcined at 1023 K for 2 h then digested in 3.0, 4.5, and 6.0 N sulfuric acid at constant temperatures within the range 328−358 K. The samples taken from the solution at predetermined time intervals were analyzed by using a complexometric method and the amount of aluminum passed into the solution was determined. The results showed that the dissolution kinetics follow the shrinking core model for spherical particles of unchanging size, t/τ = 1 − (1 − xB)1/3, with the apparent activation energy of 98.4 kJ/mol. The leaching reaction was found to be the 0.75th order with respect to acid concentration and controlled by reaction step. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101147n
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12379–12382[article] Investigation of the dissolution kinetics of meta - kaolin in H2SO4 solution [texte imprimé] / Mehmet Riza Altiokka, Auteur ; Handan Akalin, Auteur ; Nergis Melek, Auteur . - 2011 . - pp. 12379–12382.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12379–12382
Mots-clés : kinetics Résumé : Kaolin with a given size distribution was calcined at 1023 K for 2 h then digested in 3.0, 4.5, and 6.0 N sulfuric acid at constant temperatures within the range 328−358 K. The samples taken from the solution at predetermined time intervals were analyzed by using a complexometric method and the amount of aluminum passed into the solution was determined. The results showed that the dissolution kinetics follow the shrinking core model for spherical particles of unchanging size, t/τ = 1 − (1 − xB)1/3, with the apparent activation energy of 98.4 kJ/mol. The leaching reaction was found to be the 0.75th order with respect to acid concentration and controlled by reaction step. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101147n Exemplaires
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Titre : Ethanol steam reforming over Rh (1%) MgAl 2O4/ Al2O3 : a kinetic study Type de document : texte imprimé Auteurs : Cecilia Graschinsky, Auteur ; Miguel Laborde, Auteur ; Norma Amadeo, Auteur Année de publication : 2011 Article en page(s) : pp. 12383-12389 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetics Steam reforming Résumé : A kinetic study of ethanol steam-reforming reaction on Rh catalyst supported over a spinel structure (MgAl2O4/ Al2O3) was carried out. From the analysis of products distribution, the following four reactions were proposed as the reaction scheme: C2H5OH → CO + CH4 + H2 (ED), C2H5OH + H2O → CO2 + CH4 + 2H2 (ER), water-gas shift reaction, and methane steam-reforming reaction. When the initial rate method was applied, it was demonstrated that in the rate-determining step (RDS) two active sites of the same type are involved. With use of our experimental results and data obtained from the literature, a sequence of 14 elementary steps were proposed, in agreement with the reaction scheme. Taking into account both the reaction mechanism and the occurrence of two active sites in the RDS, four different kinetic expressions can be formulated in which the RDS is (1) dissociative adsorption of ethanol, (2) dehydrogenation of ethoxide, (3) C-C bond scission, or (4) reaction between two adsorbed species. Finally, when discrimination models were applied, it was verified that the mechanism that fits experimental data is that in which the RDS is the surface reaction. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23691991
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12383-12389[article] Ethanol steam reforming over Rh (1%) MgAl 2O4/ Al2O3 : a kinetic study [texte imprimé] / Cecilia Graschinsky, Auteur ; Miguel Laborde, Auteur ; Norma Amadeo, Auteur . - 2011 . - pp. 12383-12389.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12383-12389
Mots-clés : Kinetics Steam reforming Résumé : A kinetic study of ethanol steam-reforming reaction on Rh catalyst supported over a spinel structure (MgAl2O4/ Al2O3) was carried out. From the analysis of products distribution, the following four reactions were proposed as the reaction scheme: C2H5OH → CO + CH4 + H2 (ED), C2H5OH + H2O → CO2 + CH4 + 2H2 (ER), water-gas shift reaction, and methane steam-reforming reaction. When the initial rate method was applied, it was demonstrated that in the rate-determining step (RDS) two active sites of the same type are involved. With use of our experimental results and data obtained from the literature, a sequence of 14 elementary steps were proposed, in agreement with the reaction scheme. Taking into account both the reaction mechanism and the occurrence of two active sites in the RDS, four different kinetic expressions can be formulated in which the RDS is (1) dissociative adsorption of ethanol, (2) dehydrogenation of ethoxide, (3) C-C bond scission, or (4) reaction between two adsorbed species. Finally, when discrimination models were applied, it was verified that the mechanism that fits experimental data is that in which the RDS is the surface reaction. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23691991 Exemplaires
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Titre : Process engineering study of the homogenously catalyzed biodiesel synthesis in a bubble column reactor Type de document : texte imprimé Auteurs : Thomas Mollenhauer, Auteur ; Walther Klemm, Auteur ; Manfred Lauterbach, Auteur Année de publication : 2011 Article en page(s) : pp. 12390–12398 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Bubble column reactor Catalyzed biodiesel Résumé : A bubble column reactor has been developed for the production of fatty acid methyl ester (FAME) from refined oil and oil with high free fatty acid (FFA) content. The aim of our investigations was to examine the basic use of a discontinuously operated bubble reactor for homogenously catalyzed synthesis of FAME in comparison to use of a discontinuously operated stirred reactor. Stirring of the liquid phase in the bubble reactor was realized by the ascending force of bubbles which were introduced over a distribution system from the bottom of the reactor. Either the aerating nitrogen gas (at 60 °C) or vaporized methanol (at 80 °C) were used in the bubble reactor. The ascending bubbles should enable the mass transfer for transesterification and esterification of the feedstock. Further, the catalysts p-toluene sulfonic acid (p-TSS; 3 wt %) or sodium methoxide (1 wt %) were applied to an initial load of 2 L in a molar ratio of 2:1 methanol-to-feedstock related to the fatty acids. Additionally, important process engineering parameters and kinetic information were collected experimentally as well as theoretically. The results show that a bubble reactor is a serious alternative reaction technique for FAME production simplifying the devices and enabling higher throughputs per reaction unit. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101430w
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12390–12398[article] Process engineering study of the homogenously catalyzed biodiesel synthesis in a bubble column reactor [texte imprimé] / Thomas Mollenhauer, Auteur ; Walther Klemm, Auteur ; Manfred Lauterbach, Auteur . - 2011 . - pp. 12390–12398.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12390–12398
Mots-clés : Bubble column reactor Catalyzed biodiesel Résumé : A bubble column reactor has been developed for the production of fatty acid methyl ester (FAME) from refined oil and oil with high free fatty acid (FFA) content. The aim of our investigations was to examine the basic use of a discontinuously operated bubble reactor for homogenously catalyzed synthesis of FAME in comparison to use of a discontinuously operated stirred reactor. Stirring of the liquid phase in the bubble reactor was realized by the ascending force of bubbles which were introduced over a distribution system from the bottom of the reactor. Either the aerating nitrogen gas (at 60 °C) or vaporized methanol (at 80 °C) were used in the bubble reactor. The ascending bubbles should enable the mass transfer for transesterification and esterification of the feedstock. Further, the catalysts p-toluene sulfonic acid (p-TSS; 3 wt %) or sodium methoxide (1 wt %) were applied to an initial load of 2 L in a molar ratio of 2:1 methanol-to-feedstock related to the fatty acids. Additionally, important process engineering parameters and kinetic information were collected experimentally as well as theoretically. The results show that a bubble reactor is a serious alternative reaction technique for FAME production simplifying the devices and enabling higher throughputs per reaction unit. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101430w Exemplaires
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Titre : Etherification of glycerol with isobutylene to produce oxygenate additive using sulfonated peanut shell catalyst Type de document : texte imprimé Auteurs : Weiqin Zhao, Auteur ; Bolun Yang, Auteur ; Chunhai Yi, Auteur Année de publication : 2011 Article en page(s) : pp. 12399-12404 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalyst Additive Etherification Résumé : A carbon-based solid acid catalyst was prepared by sulfonation of partially carbonized peanut shell, and characterized by SEM, EDS, BET analysis, FTIR spectroscopy, NH3 TPD, and TGA. The analytic results indicate that sulfonated peanut shell catalyst has an amorphous porous structure with a high acid capacity and good thermal stability and exhibits better catalytic activity for the glycerol etherification reaction than cation-exchange resin. With a molar ratio of isobutylene to glycerol of 4: a catalyst-to-glycerol mass ratio of 6 wt %, a reaction temperature of 343 K, and a reaction time of 2 h, glycerol was completely transformed into a mixture of glycerol ethers including mono-tert-butylglycerols (MTBGs), di-tert-butylglycerols (DTBGs), and tri-tert-butylglycerol (TTBG), and the selectivity toward the sum of the desired DTBGs and TTBG of 92.1% was obtained. Moreover, excellent reusability of the catalyst was also confirmed by repeated experiments. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23691993
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12399-12404[article] Etherification of glycerol with isobutylene to produce oxygenate additive using sulfonated peanut shell catalyst [texte imprimé] / Weiqin Zhao, Auteur ; Bolun Yang, Auteur ; Chunhai Yi, Auteur . - 2011 . - pp. 12399-12404.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12399-12404
Mots-clés : Catalyst Additive Etherification Résumé : A carbon-based solid acid catalyst was prepared by sulfonation of partially carbonized peanut shell, and characterized by SEM, EDS, BET analysis, FTIR spectroscopy, NH3 TPD, and TGA. The analytic results indicate that sulfonated peanut shell catalyst has an amorphous porous structure with a high acid capacity and good thermal stability and exhibits better catalytic activity for the glycerol etherification reaction than cation-exchange resin. With a molar ratio of isobutylene to glycerol of 4: a catalyst-to-glycerol mass ratio of 6 wt %, a reaction temperature of 343 K, and a reaction time of 2 h, glycerol was completely transformed into a mixture of glycerol ethers including mono-tert-butylglycerols (MTBGs), di-tert-butylglycerols (DTBGs), and tri-tert-butylglycerol (TTBG), and the selectivity toward the sum of the desired DTBGs and TTBG of 92.1% was obtained. Moreover, excellent reusability of the catalyst was also confirmed by repeated experiments. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23691993 Exemplaires
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Titre : Fe2+ - Catalyzed wet oxidation of phenolic acids under different pH values Type de document : texte imprimé Auteurs : Sergio Collado, Auteur ; David Quero, Auteur ; Adriana Laca, Auteur Année de publication : 2011 Article en page(s) : pp. 12405–12413 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalytic oxidation Aqueous phase Résumé : Catalytic oxidation in the aqueous phase of phenol and phenol-derivates present in pharmaceutical wastewaters has been investigated using FeSO4·7H2O as a homogeneous catalyst at 413 K and 1.0 MPa. Different initial pH values and catalyst concentrations have been tested, and the results obtained have been discussed taking into account the different roles that the iron plays depending on the pH value and the phenolic compound studied. The degradation rate of each pollutant assayed and the degree of mineralization achieved during the wet oxidation process were greatly affected by pH. The catalytic effect of iron(II) during the wet oxidation of phenol was only observed at pH values ranging between 2 and 3, due to the establishment of a Fe(III)/Fe(II) redox cycle. However, the best results for the catalytic oxidation of salicylic acid were obtained for pH values below 2, and they were related to the formation of an Fe(II)−salicylic acid complex. On the other hand, the presence of iron(II) had a prejudicial effect on the degradation of p-hydroxybenzoic and 5-hydroxyisophthalic acids, provoking the apparition of induction periods in both cases, due to the competition between the autoxidation of Fe(II) and the hydroxylation of the phenolic compound by the initial OH•. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101497s
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12405–12413[article] Fe2+ - Catalyzed wet oxidation of phenolic acids under different pH values [texte imprimé] / Sergio Collado, Auteur ; David Quero, Auteur ; Adriana Laca, Auteur . - 2011 . - pp. 12405–12413.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12405–12413
Mots-clés : Catalytic oxidation Aqueous phase Résumé : Catalytic oxidation in the aqueous phase of phenol and phenol-derivates present in pharmaceutical wastewaters has been investigated using FeSO4·7H2O as a homogeneous catalyst at 413 K and 1.0 MPa. Different initial pH values and catalyst concentrations have been tested, and the results obtained have been discussed taking into account the different roles that the iron plays depending on the pH value and the phenolic compound studied. The degradation rate of each pollutant assayed and the degree of mineralization achieved during the wet oxidation process were greatly affected by pH. The catalytic effect of iron(II) during the wet oxidation of phenol was only observed at pH values ranging between 2 and 3, due to the establishment of a Fe(III)/Fe(II) redox cycle. However, the best results for the catalytic oxidation of salicylic acid were obtained for pH values below 2, and they were related to the formation of an Fe(II)−salicylic acid complex. On the other hand, the presence of iron(II) had a prejudicial effect on the degradation of p-hydroxybenzoic and 5-hydroxyisophthalic acids, provoking the apparition of induction periods in both cases, due to the competition between the autoxidation of Fe(II) and the hydroxylation of the phenolic compound by the initial OH•. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101497s Exemplaires
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Titre : Epoxy resins cross - linked with rosin adduct derivatives. cross - linking and thermal behaviors Type de document : texte imprimé Auteurs : Fanica R. Mustata, Auteur ; Nita Tudorachi, Auteur Année de publication : 2011 Article en page(s) : pp. 12414-12422 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Rosin adduct derivatives Résumé : Rosin adduct derivatives were obtained by chemical reaction of the Diels—Alder adduct of rosin acid with maleic anhydride (RAMA) with aspartic acid (ASP) and p-aminobenzoic acid (p-ABA), at 1/1 molar ratio. The structure of the obtained monomers was established by means of elemental analysis, FT-IR spectroscopy, and 1H NMR. These acids were used as cross-linking agents, in the presence of triethylbenzylammonium chloride as catalyst (TEBAC) for diglycidyl monomers (diglycidyl ether of bisphenol A, DGEBA, and diglycidyl ether of hydroquinone, DGEHQ). Using differential scanning calorimetry (DSC) at different heating rates and the literature methods, the kinetic parameters of cross-linking reactions were obtained. The thermal stability of the cross-linked polymers investigated by using thermogravimetric analysis (TGA) showed they are reasonably thermostable. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101746v
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12414-12422[article] Epoxy resins cross - linked with rosin adduct derivatives. cross - linking and thermal behaviors [texte imprimé] / Fanica R. Mustata, Auteur ; Nita Tudorachi, Auteur . - 2011 . - pp. 12414-12422.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12414-12422
Mots-clés : Rosin adduct derivatives Résumé : Rosin adduct derivatives were obtained by chemical reaction of the Diels—Alder adduct of rosin acid with maleic anhydride (RAMA) with aspartic acid (ASP) and p-aminobenzoic acid (p-ABA), at 1/1 molar ratio. The structure of the obtained monomers was established by means of elemental analysis, FT-IR spectroscopy, and 1H NMR. These acids were used as cross-linking agents, in the presence of triethylbenzylammonium chloride as catalyst (TEBAC) for diglycidyl monomers (diglycidyl ether of bisphenol A, DGEBA, and diglycidyl ether of hydroquinone, DGEHQ). Using differential scanning calorimetry (DSC) at different heating rates and the literature methods, the kinetic parameters of cross-linking reactions were obtained. The thermal stability of the cross-linked polymers investigated by using thermogravimetric analysis (TGA) showed they are reasonably thermostable. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101746v Exemplaires
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Titre : Synthesis of Ni - SiO2/silicalite -1 core - shell micromembrane reactors and their reaction / diffusion performance Type de document : texte imprimé Auteurs : Easir A. Khan, Auteur ; Arvind Rajendran, Auteur ; Zhiping Lai, Auteur Année de publication : 2011 Article en page(s) : pp. 12423-12428 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Diffusion Reactor Résumé : Core—shell micromembrane reactors are a novel class of materials where a catalyst and a shape-selective membrane are synergistically housed in a single particle. In this work, we report the synthesis of micrometer -sized core-shell particles containing a catalyst core and a thin permselective zeolite shell and their application as a micromembrane reactor for the selective hydrogenation of the 1-hexene and 3,3-dimethyl-1-butene isomers. The bare catalyst, which is made from porous silica loaded with catalytically active nickel, showed no reactant selectivity between hexene isomers, but the core-shell particles showed high selectivities up to 300 for a 1-hexene conversion of 90%. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23691996
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12423-12428[article] Synthesis of Ni - SiO2/silicalite -1 core - shell micromembrane reactors and their reaction / diffusion performance [texte imprimé] / Easir A. Khan, Auteur ; Arvind Rajendran, Auteur ; Zhiping Lai, Auteur . - 2011 . - pp. 12423-12428.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12423-12428
Mots-clés : Diffusion Reactor Résumé : Core—shell micromembrane reactors are a novel class of materials where a catalyst and a shape-selective membrane are synergistically housed in a single particle. In this work, we report the synthesis of micrometer -sized core-shell particles containing a catalyst core and a thin permselective zeolite shell and their application as a micromembrane reactor for the selective hydrogenation of the 1-hexene and 3,3-dimethyl-1-butene isomers. The bare catalyst, which is made from porous silica loaded with catalytically active nickel, showed no reactant selectivity between hexene isomers, but the core-shell particles showed high selectivities up to 300 for a 1-hexene conversion of 90%. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23691996 Exemplaires
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Titre : Ca(OH)2 superheating as a low - attrition steam reactivation method for CaO in calcium looping applications Type de document : texte imprimé Auteurs : Vlatko Materic, Auteur ; Susan Edwards, Auteur ; Stuart I. Smedley, Auteur Année de publication : 2011 Article en page(s) : pp.12429-12434 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Attrition rate Calcium Carbonation/calcination cycle Dehydration reactions Dewatering Fluid-beds Fluidization Free lime Heat storage Hydration Initiation temperature Lime Non equilibrium Reactivation process Sorption Steam hydration Superheated state Temperature Thermodynamic equilibria water vapor Résumé : Steam hydration of lime is an effective method for restoring CO2 capture activity but gives rise to high particle attrition rates in a fluid bed reactor. This paper describes the phenomenon of Ca(OH)2 superheating, also referred to as superheated dehydration (SD). The potential of an attrition-free lime reactivation process using this phenomenon is also investigated. Attrition rates of the sorbent are measured when a reactivation step using steam hydration is implemented every three carbonation/calcination cycles. It has been shown that the presence of CO2 during the dehydration step reduces attrition during subsequent cycles. Experiments performed in a small fluid bed reactor show that the presence of 40-100% CO 2 during the dehydration step increases the initiation temperature of the decomposition of Ca(OH)2 from 445 to 618 °C. The thermodynamic equilibrium water vapor pressure for the dehydration reaction at 618 °C is 516 kPa, whereas no water vapor was detected in the reactor during the dehydration step before the temperature reached 618 °C. Under these circumstances it is proposed that the Ca(OH)2 is in a nonequilibrium "superheated state". A CO2 capture cycling experiment, with a reactivation step every three carbonation/calcination cycles, maintained an average activity of 60%, creating only 3.25% of fines DEWEY : 660 ISSN : 0888-5885 En ligne : http://www.irl.cri.nz/caoh2-superheating-low-attrition-steam-reactivation-method [...]
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp.12429-12434[article] Ca(OH)2 superheating as a low - attrition steam reactivation method for CaO in calcium looping applications [texte imprimé] / Vlatko Materic, Auteur ; Susan Edwards, Auteur ; Stuart I. Smedley, Auteur . - 2011 . - pp.12429-12434.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp.12429-12434
Mots-clés : Attrition rate Calcium Carbonation/calcination cycle Dehydration reactions Dewatering Fluid-beds Fluidization Free lime Heat storage Hydration Initiation temperature Lime Non equilibrium Reactivation process Sorption Steam hydration Superheated state Temperature Thermodynamic equilibria water vapor Résumé : Steam hydration of lime is an effective method for restoring CO2 capture activity but gives rise to high particle attrition rates in a fluid bed reactor. This paper describes the phenomenon of Ca(OH)2 superheating, also referred to as superheated dehydration (SD). The potential of an attrition-free lime reactivation process using this phenomenon is also investigated. Attrition rates of the sorbent are measured when a reactivation step using steam hydration is implemented every three carbonation/calcination cycles. It has been shown that the presence of CO2 during the dehydration step reduces attrition during subsequent cycles. Experiments performed in a small fluid bed reactor show that the presence of 40-100% CO 2 during the dehydration step increases the initiation temperature of the decomposition of Ca(OH)2 from 445 to 618 °C. The thermodynamic equilibrium water vapor pressure for the dehydration reaction at 618 °C is 516 kPa, whereas no water vapor was detected in the reactor during the dehydration step before the temperature reached 618 °C. Under these circumstances it is proposed that the Ca(OH)2 is in a nonequilibrium "superheated state". A CO2 capture cycling experiment, with a reactivation step every three carbonation/calcination cycles, maintained an average activity of 60%, creating only 3.25% of fines DEWEY : 660 ISSN : 0888-5885 En ligne : http://www.irl.cri.nz/caoh2-superheating-low-attrition-steam-reactivation-method [...] Exemplaires
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Titre : Stable citrate - coated iron oxide superparamagnetic nanoclusters at high salinity Type de document : texte imprimé Auteurs : Csaba Kotsmar, Auteur ; Ki Youl Yoon, Auteur ; Haiyang Yu, Auteur Année de publication : 2011 Article en page(s) : pp. 12435–12443 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Superparamagnetic nanoclusters Résumé : Superparamagnetic nanoclusters may be used in imaging in biomedicine and in mapping of petroleum reservoirs, by generating either ultrasonic or acoustic signals with oscillating magnetic motion. For a given magnetization per weight of iron oxide, nanoclusters with diameters from 20 to 100 nm experience a much larger magnetic force than that of the primary sub-10-nm primary particles. Aqueous dispersions of 0.1 wt % superparamagnetic iron oxide nanoclusters were stabilized with citric acid on the particle surface, with a high loading of 90% iron oxide. The dispersions were stable for months even with high salt concentrations up to 4 wt % at a pH of 6 and 8 based on the hydrodynamic diameter from dynamic light scattering. The citrate ligands provide electrostatic repulsion, as characterized by the ζ potential. The small size of the clusters, superparamagnetic properties, and high salt tolerance are highly beneficial in various applications including the mapping of petroleum reservoirs with magnetomotive techniques. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1010965
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12435–12443[article] Stable citrate - coated iron oxide superparamagnetic nanoclusters at high salinity [texte imprimé] / Csaba Kotsmar, Auteur ; Ki Youl Yoon, Auteur ; Haiyang Yu, Auteur . - 2011 . - pp. 12435–12443.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12435–12443
Mots-clés : Superparamagnetic nanoclusters Résumé : Superparamagnetic nanoclusters may be used in imaging in biomedicine and in mapping of petroleum reservoirs, by generating either ultrasonic or acoustic signals with oscillating magnetic motion. For a given magnetization per weight of iron oxide, nanoclusters with diameters from 20 to 100 nm experience a much larger magnetic force than that of the primary sub-10-nm primary particles. Aqueous dispersions of 0.1 wt % superparamagnetic iron oxide nanoclusters were stabilized with citric acid on the particle surface, with a high loading of 90% iron oxide. The dispersions were stable for months even with high salt concentrations up to 4 wt % at a pH of 6 and 8 based on the hydrodynamic diameter from dynamic light scattering. The citrate ligands provide electrostatic repulsion, as characterized by the ζ potential. The small size of the clusters, superparamagnetic properties, and high salt tolerance are highly beneficial in various applications including the mapping of petroleum reservoirs with magnetomotive techniques. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1010965 Exemplaires
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Titre : Rubbery polymer − inorganic nanocomposite membranes : free volume characteristics on separation property Type de document : texte imprimé Auteurs : Ben Li, Auteur ; Dan Xu, Auteur ; Xiongfei Zhang, Auteur Année de publication : 2011 Article en page(s) : pp. 12444–12451 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nanocomposite Polymer inorganic Résumé : The rational design of polymer−inorganic nanocomposite membranes relies heavily on the precise insight and elaborate control of the interface. Presently, the direct exploration of the hierarchical structure of nanocomposite membranes still remains elusive. In the present study, we propose a facile and generic methodology to quantitatively probe the interfacial structure by complementary positron annihilation lifetime spectroscopy (PALS) and molecular dynamics simulation (MDS) techniques. MDS is used to acquire the molecular level information such as the polymer−inorganic interface interaction energy, chain mobility within the nanocomposite membranes, whereas PALS is used to acquire the free volume characteristics of the nanocomposite membranes. As proof-of-principle, we choose anisotropic inorganic nanotube embedded rubbery polymer membrane as a model, which generates the interface between soft polymer and rigid inorganic. PALS reveals that incorporation of titanate nanotubes (TNTs) narrows the free volume pore radius distribution of the membranes. MDS indicates that the segmental chain mobility in the vicinity of the polymer−inorganic interface is substantially restrained, which creates numerous nanosized voids for molecular transport, and dramatically enhances the fractional free volume (FFV) of the membranes. Quite interestingly, it was found that the rubbery membranes can also exhibit simultaneously increased permeability and membrane selectivity, and this unusual phenomenon was tentatively elucidated by relating the separation properties to the free volume characteristics of the membranes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101142b
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12444–12451[article] Rubbery polymer − inorganic nanocomposite membranes : free volume characteristics on separation property [texte imprimé] / Ben Li, Auteur ; Dan Xu, Auteur ; Xiongfei Zhang, Auteur . - 2011 . - pp. 12444–12451.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12444–12451
Mots-clés : Nanocomposite Polymer inorganic Résumé : The rational design of polymer−inorganic nanocomposite membranes relies heavily on the precise insight and elaborate control of the interface. Presently, the direct exploration of the hierarchical structure of nanocomposite membranes still remains elusive. In the present study, we propose a facile and generic methodology to quantitatively probe the interfacial structure by complementary positron annihilation lifetime spectroscopy (PALS) and molecular dynamics simulation (MDS) techniques. MDS is used to acquire the molecular level information such as the polymer−inorganic interface interaction energy, chain mobility within the nanocomposite membranes, whereas PALS is used to acquire the free volume characteristics of the nanocomposite membranes. As proof-of-principle, we choose anisotropic inorganic nanotube embedded rubbery polymer membrane as a model, which generates the interface between soft polymer and rigid inorganic. PALS reveals that incorporation of titanate nanotubes (TNTs) narrows the free volume pore radius distribution of the membranes. MDS indicates that the segmental chain mobility in the vicinity of the polymer−inorganic interface is substantially restrained, which creates numerous nanosized voids for molecular transport, and dramatically enhances the fractional free volume (FFV) of the membranes. Quite interestingly, it was found that the rubbery membranes can also exhibit simultaneously increased permeability and membrane selectivity, and this unusual phenomenon was tentatively elucidated by relating the separation properties to the free volume characteristics of the membranes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101142b Exemplaires
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Titre : Comparison of the corrosion inhibitive effect of anaerobic and aerobic cigarette butts water extracts on N80 steel at 90 °C in hydrochloric acid solution Type de document : texte imprimé Auteurs : Jun Zhao, Auteur ; Ningsheng Zhang, Auteur ; Chengtun Qu, Auteur Année de publication : 2011 Article en page(s) : pp. 12452-12460 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Steel Extract Aerobe Anaerobe Corrosion Résumé : The chemical compositions of cigarette butts water extracts mainly are aromatic amines including nicotine and its compounds. If oxygen exists, the aromatic amine compounds can be oxidized easily. Whether this oxidation would be beneficial in enhancing the corrosion inhibitive effect of the inhibitor is not known. In this study, the corrosion inhibitive effect of aerobic and anaerobic cigarette butts water extracts are compared on N80 steel at 90 °C in 15% (weight %) hydrochloric acid. The chemical compositions of the aerobic and anaerobic cigarette butts water extracts are also contrasted. Weight loss, X-ray diffraction, and electrochemical techniques (such as electrochemical noise, impedance, and potentiodynamic polarization) are used to evaluate the corrosion inhibitive effect of aerobic and anaerobic cigarette butts water extracts. Results show that the inhibition efficiency of the aerobic cigarette butts water extracts (92.9%) is higher than anaerobic cigarette butts water extracts (84.6%). DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692000
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12452-12460[article] Comparison of the corrosion inhibitive effect of anaerobic and aerobic cigarette butts water extracts on N80 steel at 90 °C in hydrochloric acid solution [texte imprimé] / Jun Zhao, Auteur ; Ningsheng Zhang, Auteur ; Chengtun Qu, Auteur . - 2011 . - pp. 12452-12460.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12452-12460
Mots-clés : Steel Extract Aerobe Anaerobe Corrosion Résumé : The chemical compositions of cigarette butts water extracts mainly are aromatic amines including nicotine and its compounds. If oxygen exists, the aromatic amine compounds can be oxidized easily. Whether this oxidation would be beneficial in enhancing the corrosion inhibitive effect of the inhibitor is not known. In this study, the corrosion inhibitive effect of aerobic and anaerobic cigarette butts water extracts are compared on N80 steel at 90 °C in 15% (weight %) hydrochloric acid. The chemical compositions of the aerobic and anaerobic cigarette butts water extracts are also contrasted. Weight loss, X-ray diffraction, and electrochemical techniques (such as electrochemical noise, impedance, and potentiodynamic polarization) are used to evaluate the corrosion inhibitive effect of aerobic and anaerobic cigarette butts water extracts. Results show that the inhibition efficiency of the aerobic cigarette butts water extracts (92.9%) is higher than anaerobic cigarette butts water extracts (84.6%). DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692000 Exemplaires
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Titre : Meniscus - shear particle detachment in foam - based cleaning of silicon wafers with an immersion / withdrawal cell Type de document : texte imprimé Auteurs : V. A. Andreev, Auteur ; J. M. Prausnitz, Auteur ; C. J. Radke, Auteur Année de publication : 2011 Article en page(s) : pp. 12461–12470 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : silicon Résumé : New experimental data collected at Lam Research Corporation and theoretical analyses are presented for aqueous-foam cleaning of silicon wafers contaminated with strongly adhered 90 nm Si3N4 particles (Freer et al. 2010). We analyze the distribution of contaminant removal along the wafer surface and the influence of foam quality in a vertical rectangular slot upon wafer immersion/withdrawal. At zero foam quality, particle removal along the wafer surface is uniform. Increased foam quality leads to improved overall removal. Removal, however, is no longer uniform with larger detachment rates toward the bottom of the wafer. To explain the observed nonuniform particle removal, we adopt a binary-collision model that demands a linear dependence of removal rate on the surface shear rate. Perturbation analysis provides the distribution of the wall shear rate along the wafer surface in an unfoamed solution. Calculations show that the wall shear rate on the wafer surface is strongly peaked in the meniscus just above the liquid-filled slot. Thus, with no foam present, removal in the meniscus zone dominates the overall removal process. Because the time of exposure to this high shear is the same for all parts of the surface, we obtain uniform cleaning. With foam bubbles present, the wall shear rate in the slot is enhanced, leading to significant removal in the bulk of the slot. Because the residence time of a wafer in the bulk cleaning solution varies for different parts of the wafer, contaminant removal in the bulk of the slot depends on the vertical position. Combined particle removal in the meniscus zone and in the slot leads to the observed nonuniform distribution of contaminant particles remaining on the wafer surface. Increasing foam quality increases the slot wall shear rate and, hence, the removal rate inside the immersion/withdrawal cell. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1012954
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12461–12470[article] Meniscus - shear particle detachment in foam - based cleaning of silicon wafers with an immersion / withdrawal cell [texte imprimé] / V. A. Andreev, Auteur ; J. M. Prausnitz, Auteur ; C. J. Radke, Auteur . - 2011 . - pp. 12461–12470.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12461–12470
Mots-clés : silicon Résumé : New experimental data collected at Lam Research Corporation and theoretical analyses are presented for aqueous-foam cleaning of silicon wafers contaminated with strongly adhered 90 nm Si3N4 particles (Freer et al. 2010). We analyze the distribution of contaminant removal along the wafer surface and the influence of foam quality in a vertical rectangular slot upon wafer immersion/withdrawal. At zero foam quality, particle removal along the wafer surface is uniform. Increased foam quality leads to improved overall removal. Removal, however, is no longer uniform with larger detachment rates toward the bottom of the wafer. To explain the observed nonuniform particle removal, we adopt a binary-collision model that demands a linear dependence of removal rate on the surface shear rate. Perturbation analysis provides the distribution of the wall shear rate along the wafer surface in an unfoamed solution. Calculations show that the wall shear rate on the wafer surface is strongly peaked in the meniscus just above the liquid-filled slot. Thus, with no foam present, removal in the meniscus zone dominates the overall removal process. Because the time of exposure to this high shear is the same for all parts of the surface, we obtain uniform cleaning. With foam bubbles present, the wall shear rate in the slot is enhanced, leading to significant removal in the bulk of the slot. Because the residence time of a wafer in the bulk cleaning solution varies for different parts of the wafer, contaminant removal in the bulk of the slot depends on the vertical position. Combined particle removal in the meniscus zone and in the slot leads to the observed nonuniform distribution of contaminant particles remaining on the wafer surface. Increasing foam quality increases the slot wall shear rate and, hence, the removal rate inside the immersion/withdrawal cell. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1012954 Exemplaires
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Titre : High - performance hybrid magnetorheological materials : preparation and mechanical properties Type de document : texte imprimé Auteurs : W. Zhang, Auteur ; X. L. Gong, Auteur ; S. H. Xuan, Auteur Année de publication : 2011 Article en page(s) : pp12471–12476 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Magnetorheological Mechanical properties Résumé : To improve mechanical performance of magnetorheological elastomers (MREs), two novel hybrid magnetorheological elastomers that were embedded with magnetorheological fluids (MRFs) and magnetorheological gels (MRGs) were fabricated. In this work, MRFs and MRGs were injected into different numbers of holes that were punched on MRE specimens regularly. The nonlinear mechanical properties of the as-prepared magnetorheological fluid-elastomers (MRFEs) and magnetorheological gel-elastomers (MRGEs) were investigated in the presence of external homogeneous magnetic fields. The modulus, loss factor, and hysteresis were evaluated with a modified dynamic mechanical analyzer (DMA) and vibrating sample magnetometer (VSM). Dependence of the rheological response on the volume fraction was also investigated. As the experimental results show, not only were the initial moduli of the two novel hybrid magnetorheological materials higher than those of both the MRFs and MRGs, but also their magnetorheological (MR) effects were better than those of MREs. The loss factors of the two new hybrids were different from those of traditional MREs. Moreover, their dynamic properties changed according to the different volume ratios of MRFs and MRGs injected into the MRE specimens. These results suggest that the two novel hybrid magnetorheological elastomers are improved systems with volume-fraction-dependent rheological responses and the mechanical properties of MREs can be improved by embedding them with MRFs and MRGs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101904f
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp12471–12476[article] High - performance hybrid magnetorheological materials : preparation and mechanical properties [texte imprimé] / W. Zhang, Auteur ; X. L. Gong, Auteur ; S. H. Xuan, Auteur . - 2011 . - pp12471–12476.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp12471–12476
Mots-clés : Magnetorheological Mechanical properties Résumé : To improve mechanical performance of magnetorheological elastomers (MREs), two novel hybrid magnetorheological elastomers that were embedded with magnetorheological fluids (MRFs) and magnetorheological gels (MRGs) were fabricated. In this work, MRFs and MRGs were injected into different numbers of holes that were punched on MRE specimens regularly. The nonlinear mechanical properties of the as-prepared magnetorheological fluid-elastomers (MRFEs) and magnetorheological gel-elastomers (MRGEs) were investigated in the presence of external homogeneous magnetic fields. The modulus, loss factor, and hysteresis were evaluated with a modified dynamic mechanical analyzer (DMA) and vibrating sample magnetometer (VSM). Dependence of the rheological response on the volume fraction was also investigated. As the experimental results show, not only were the initial moduli of the two novel hybrid magnetorheological materials higher than those of both the MRFs and MRGs, but also their magnetorheological (MR) effects were better than those of MREs. The loss factors of the two new hybrids were different from those of traditional MREs. Moreover, their dynamic properties changed according to the different volume ratios of MRFs and MRGs injected into the MRE specimens. These results suggest that the two novel hybrid magnetorheological elastomers are improved systems with volume-fraction-dependent rheological responses and the mechanical properties of MREs can be improved by embedding them with MRFs and MRGs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101904f Exemplaires
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Titre : Improving the computational performance of STN / RTN formulations for short - term scheduling Type de document : texte imprimé Auteurs : Guillermo A. Durand, Auteur ; J. Alberto Bandoni, Auteur Année de publication : 2011 Article en page(s) : pp. 12477-12495 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Scheduling Short term Résumé : In this article, we present a series of integer cuts to improve the computational performance of scheduling problems based on either discrete- or continuous-time representation. They are expressed as novel equations in terms of binary variables alone that take advantage of structural characteristic of general STN and RTN formulations. Different fixed pairs of tasks appearing in scheduling problems of continuous and batch-continuous processes are identified, and corresponding integer cuts are developed to improve the solution efficiency of the mathematical formulations. For demonstration purposes, five selected scheduling formulations are modified as proposed in this article and applied to three well-known benchmark problems, and their computational performances are compared against the unmodified formulations. An industrial case study is also used to demonstrate the advantages of using the new equations. This case study corresponds to a sector, the so-called "sugarhouse", of a beet sugar plant. The scheduling model is presented, and the results are discussed in terms of both the optimal plant schedule and the computational point of view. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692003
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12477-12495[article] Improving the computational performance of STN / RTN formulations for short - term scheduling [texte imprimé] / Guillermo A. Durand, Auteur ; J. Alberto Bandoni, Auteur . - 2011 . - pp. 12477-12495.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12477-12495
Mots-clés : Scheduling Short term Résumé : In this article, we present a series of integer cuts to improve the computational performance of scheduling problems based on either discrete- or continuous-time representation. They are expressed as novel equations in terms of binary variables alone that take advantage of structural characteristic of general STN and RTN formulations. Different fixed pairs of tasks appearing in scheduling problems of continuous and batch-continuous processes are identified, and corresponding integer cuts are developed to improve the solution efficiency of the mathematical formulations. For demonstration purposes, five selected scheduling formulations are modified as proposed in this article and applied to three well-known benchmark problems, and their computational performances are compared against the unmodified formulations. An industrial case study is also used to demonstrate the advantages of using the new equations. This case study corresponds to a sector, the so-called "sugarhouse", of a beet sugar plant. The scheduling model is presented, and the results are discussed in terms of both the optimal plant schedule and the computational point of view. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692003 Exemplaires
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Titre : Thermodynamic analysis on work transfer process of two gas streams Type de document : texte imprimé Auteurs : Jian - Qiang Deng, Auteur ; Ji - Quan Shi, Auteur ; Zao - Xiao Zhang, Auteur Année de publication : 2011 Article en page(s) : pp. 12496-12502 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Thermodynamic analysis Résumé : A novel concept of gas-gas work exchanger (WE) is proposed for recovery of mechanical energy. Its thermodynamic process is analyzed by using the energy conservation law and the real gas's pressure-specific enthalpy diagram. An in-depth work evaluation model of the work transfer process is carried out. A simplified equation for quick forecast work recovery efficiency of a gas-gas work exchanger is derived. The performances of a gas-gas work exchanger are analyzed by predigesting some precondition. The work recovery efficiency of a gas—gas work exchanger is found to be lower than that of a liquid-liquid work exchanger, e.g., the work recovery efficiency of a diatomic molecule gas drops from 0.75 to 0.46 as the compression ratio is increased from 1.5 to 3.0. The higher compression rate results in more work loss. In the example case of this work, supposing the same nitrogen stream supplies the power for recovery, a three-stage recovery process can recover 79% more power than a single stage process. A low-pressure stream can be compressed and rise its temperature far higher than that of two original temperatures of the streams. It is a new approach to energy transfer driven by pressure difference and it is wholly different from the heat transfer in a heat exchanger (HE). A network combining WEs with HEs is proposed for recovering energy thoroughly and flexibly. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692004
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12496-12502[article] Thermodynamic analysis on work transfer process of two gas streams [texte imprimé] / Jian - Qiang Deng, Auteur ; Ji - Quan Shi, Auteur ; Zao - Xiao Zhang, Auteur . - 2011 . - pp. 12496-12502.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12496-12502
Mots-clés : Thermodynamic analysis Résumé : A novel concept of gas-gas work exchanger (WE) is proposed for recovery of mechanical energy. Its thermodynamic process is analyzed by using the energy conservation law and the real gas's pressure-specific enthalpy diagram. An in-depth work evaluation model of the work transfer process is carried out. A simplified equation for quick forecast work recovery efficiency of a gas-gas work exchanger is derived. The performances of a gas-gas work exchanger are analyzed by predigesting some precondition. The work recovery efficiency of a gas—gas work exchanger is found to be lower than that of a liquid-liquid work exchanger, e.g., the work recovery efficiency of a diatomic molecule gas drops from 0.75 to 0.46 as the compression ratio is increased from 1.5 to 3.0. The higher compression rate results in more work loss. In the example case of this work, supposing the same nitrogen stream supplies the power for recovery, a three-stage recovery process can recover 79% more power than a single stage process. A low-pressure stream can be compressed and rise its temperature far higher than that of two original temperatures of the streams. It is a new approach to energy transfer driven by pressure difference and it is wholly different from the heat transfer in a heat exchanger (HE). A network combining WEs with HEs is proposed for recovering energy thoroughly and flexibly. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692004 Exemplaires
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Titre : Pharmaceutical salt formation guided by phase diagrams Type de document : texte imprimé Auteurs : Ka W. Lam, Auteur ; Jinjie Xu, Auteur ; Ka M. Ng, Auteur Année de publication : 2011 Article en page(s) : pp. 12503-12512 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Phase diagram Résumé : Salt formation is frequently employed to improve the solubility and bioavailability of pharmaceutical compounds. Solid-liquid equilibrium (SLE) phase diagram that serves as the foundation for designing crystallization-based separation is introduced to facilitate the recovery of the desired salt form. Two poorly water-soluble drugs, each with two ionizable groups, were selected to demonstrate this phase diagram-guided approach. The first is pemetrexed with confirmed monosodium and disodium salt forms. The second drug is the orally administered dapsone for which no known salt form has been established. Dihydrochloric salt of dapsone was successfully formed alongside the experimental phase diagram. Its solubility was found to be 80 times higher than that of the parent drug. Caco-2 cell assays showed that the intestinal permeability of the dihydrochloric salt was as good as that of the parent drug, thus confirming the usefulness of the salt form. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692005
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12503-12512[article] Pharmaceutical salt formation guided by phase diagrams [texte imprimé] / Ka W. Lam, Auteur ; Jinjie Xu, Auteur ; Ka M. Ng, Auteur . - 2011 . - pp. 12503-12512.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12503-12512
Mots-clés : Phase diagram Résumé : Salt formation is frequently employed to improve the solubility and bioavailability of pharmaceutical compounds. Solid-liquid equilibrium (SLE) phase diagram that serves as the foundation for designing crystallization-based separation is introduced to facilitate the recovery of the desired salt form. Two poorly water-soluble drugs, each with two ionizable groups, were selected to demonstrate this phase diagram-guided approach. The first is pemetrexed with confirmed monosodium and disodium salt forms. The second drug is the orally administered dapsone for which no known salt form has been established. Dihydrochloric salt of dapsone was successfully formed alongside the experimental phase diagram. Its solubility was found to be 80 times higher than that of the parent drug. Caco-2 cell assays showed that the intestinal permeability of the dihydrochloric salt was as good as that of the parent drug, thus confirming the usefulness of the salt form. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692005 Exemplaires
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Titre : Thickeners in vat dye textile printing : rheology and morphology Type de document : texte imprimé Auteurs : Ziad Saffour, Auteur ; Chuang C. Wang, Auteur ; Pierre Viallier, Auteur Année de publication : 2011 Article en page(s) : pp. 12513-12520 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Morphology Textile industry Vat dye Résumé : This paper is a study of the thickeners used in two-phase vat dye textile printing. Throughout this complex process, the thickener dispersion undergoes several transformations, especially spreading on the textile material, drying, and coagulation. Empirical knowledge prescribes several requirements in terms of viscosity but also concerning the dried thickener. But, a better understanding of the phenomena is necessary to determine the origin of possible failure if the basic recipe is modified. Three different thickeners are considered: guaranate, alginate, and modified starch, as well as a combination of these three polymers. Their rheological properties are characterized in both permanent and oscillatory shear flow. Use of a mixture of polymers instead of a simple one avoids undesirable effects of thixotropy, yield stress, and elasticity, for a given value of the viscosity. The process involves the gelation of the thickener by cross-linking of guaranate chains with borate ions. The mechanical properties of such gels strongly depend on the pH, and their stability is affected by the presence of salt. Additionally, thickener films are dried under different conditions, and the morphology of the film is observed at different scales. It is shown that rapid drying at high temperature prevents crystalline structures obtained in the case of slow drying under ambient conditions. This is propitious to a good flexibility of the polymer film, suitable for fabric handling, good swelling in the steamer, and easy washing off. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692006
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12513-12520[article] Thickeners in vat dye textile printing : rheology and morphology [texte imprimé] / Ziad Saffour, Auteur ; Chuang C. Wang, Auteur ; Pierre Viallier, Auteur . - 2011 . - pp. 12513-12520.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12513-12520
Mots-clés : Morphology Textile industry Vat dye Résumé : This paper is a study of the thickeners used in two-phase vat dye textile printing. Throughout this complex process, the thickener dispersion undergoes several transformations, especially spreading on the textile material, drying, and coagulation. Empirical knowledge prescribes several requirements in terms of viscosity but also concerning the dried thickener. But, a better understanding of the phenomena is necessary to determine the origin of possible failure if the basic recipe is modified. Three different thickeners are considered: guaranate, alginate, and modified starch, as well as a combination of these three polymers. Their rheological properties are characterized in both permanent and oscillatory shear flow. Use of a mixture of polymers instead of a simple one avoids undesirable effects of thixotropy, yield stress, and elasticity, for a given value of the viscosity. The process involves the gelation of the thickener by cross-linking of guaranate chains with borate ions. The mechanical properties of such gels strongly depend on the pH, and their stability is affected by the presence of salt. Additionally, thickener films are dried under different conditions, and the morphology of the film is observed at different scales. It is shown that rapid drying at high temperature prevents crystalline structures obtained in the case of slow drying under ambient conditions. This is propitious to a good flexibility of the polymer film, suitable for fabric handling, good swelling in the steamer, and easy washing off. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692006 Exemplaires
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Titre : Decentralized control system design for MIMO processes with integrators / differentiators Type de document : texte imprimé Auteurs : Wuhua Hu, Auteur ; Wen-Jian Cai, Auteur ; Gaoxi Xiao, Auteur Année de publication : 2011 Article en page(s) : pp. 12521–12528 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : MIMO processes integrators Résumé : This work extends the concept of relative normalized gain array (RNGA) and proposes a systematic approach to designing decentralized proportional−integral−derivative (PID) control for multi-input−multi-output (MIMO) processes containing integrators and/or differentiators. By determining the input−output-pairing using the relative gain array (RGA)−Nederlinski index (NI)−RNGA criterion, equivalent transfer functions (ETFs) for the selected input−output pairs are derived by utilizing the RGA and RNGA information, which has incorporated the information on loop interactions. Based on the ETFs, decentralized PID controllers are tuned to stabilize the MIMO system independently. The proposed approach is simple, easy to understand, and easy to implement by field engineers. Three industrial MIMO processes with different dimensions and interaction modes are employed to demonstrate the efficiency of the proposed approach. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1005838
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12521–12528[article] Decentralized control system design for MIMO processes with integrators / differentiators [texte imprimé] / Wuhua Hu, Auteur ; Wen-Jian Cai, Auteur ; Gaoxi Xiao, Auteur . - 2011 . - pp. 12521–12528.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12521–12528
Mots-clés : MIMO processes integrators Résumé : This work extends the concept of relative normalized gain array (RNGA) and proposes a systematic approach to designing decentralized proportional−integral−derivative (PID) control for multi-input−multi-output (MIMO) processes containing integrators and/or differentiators. By determining the input−output-pairing using the relative gain array (RGA)−Nederlinski index (NI)−RNGA criterion, equivalent transfer functions (ETFs) for the selected input−output pairs are derived by utilizing the RGA and RNGA information, which has incorporated the information on loop interactions. Based on the ETFs, decentralized PID controllers are tuned to stabilize the MIMO system independently. The proposed approach is simple, easy to understand, and easy to implement by field engineers. Three industrial MIMO processes with different dimensions and interaction modes are employed to demonstrate the efficiency of the proposed approach. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1005838 Exemplaires
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Titre : Novel syngas production techniques for GTL - FT synthesis of gasoline using reverse flow catalytic membrane reactors Type de document : texte imprimé Auteurs : C. Dillerop, Auteur ; H. Van den Berg, Auteur ; A. G. J. Van der Ham, Auteur Année de publication : 2011 Article en page(s) : pp. 12529-12537 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalytic reactor Production Synthesis gas Résumé : Syngas production plays a key role in gas-to-liquid (GTL) technology. In this feasibility study, existing and new syngas production techniques are compared. As the conventional autothermal reforming reactors (ATR) always consist of extensive heat exchange equipment and air separation units, alternatives are based on integrating these within the reactor design. Reverse flow catalytic membrane reactors (RFCMR) make it possible to perform heat integration within the reactor; integrated air separation is accomplished by incorporating O2 selective membranes. The alternatives show a higher economic potential than the conventional technique. The use of an O2 selective membrane still experiences reliability problems and was therefore not considered. The second part of the study consists of an extended conceptual design of both the conventional design as well as the reactor with integrated heat transfer. The design involved a GTL plant producing 100 000 bbl/day of gasoline. The feasibility of the reversed flow catalytic membrane reactor is shown by reduced methane and oxygen consumption. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692008
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12529-12537[article] Novel syngas production techniques for GTL - FT synthesis of gasoline using reverse flow catalytic membrane reactors [texte imprimé] / C. Dillerop, Auteur ; H. Van den Berg, Auteur ; A. G. J. Van der Ham, Auteur . - 2011 . - pp. 12529-12537.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12529-12537
Mots-clés : Catalytic reactor Production Synthesis gas Résumé : Syngas production plays a key role in gas-to-liquid (GTL) technology. In this feasibility study, existing and new syngas production techniques are compared. As the conventional autothermal reforming reactors (ATR) always consist of extensive heat exchange equipment and air separation units, alternatives are based on integrating these within the reactor design. Reverse flow catalytic membrane reactors (RFCMR) make it possible to perform heat integration within the reactor; integrated air separation is accomplished by incorporating O2 selective membranes. The alternatives show a higher economic potential than the conventional technique. The use of an O2 selective membrane still experiences reliability problems and was therefore not considered. The second part of the study consists of an extended conceptual design of both the conventional design as well as the reactor with integrated heat transfer. The design involved a GTL plant producing 100 000 bbl/day of gasoline. The feasibility of the reversed flow catalytic membrane reactor is shown by reduced methane and oxygen consumption. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692008 Exemplaires
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Titre : Plantwide control system design and performance evaluation for ammonia synthesis process Type de document : texte imprimé Auteurs : Chi Zhang, Auteur ; Suraj Vasudevan, Auteur ; G.P. Rangaiah, Auteur Année de publication : 2011 Article en page(s) : pp. 12538-12547 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : System design Control system Process control Résumé : The emphasis on process economics in modem chemical plants has led to the increased use of material recycle and energy integration that significantly alter process dynamics and add complexity. As a result, many plantwide control (PWC) methodologies have emerged. However, there are very few comparative studies to evaluate the effectiveness of alternate methodologies. In this study, a PWC structure for the ammonia synthesis process is developed using the integrated framework of simulation and heuristics [Konda et al. Ind. Eng. Chem. Res. 2005, 44, 8300-8313], which is then compared with that developed by Araújo and Skogestad [Araújo and Skogestad, Comput. Chem. Eng. 2008, 32, 2920-2932] using the self-optimizing control procedure. The different control structures are evaluated in a comprehensive manner including assessment of the dynamic performance and steady-state profit. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692009
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12538-12547[article] Plantwide control system design and performance evaluation for ammonia synthesis process [texte imprimé] / Chi Zhang, Auteur ; Suraj Vasudevan, Auteur ; G.P. Rangaiah, Auteur . - 2011 . - pp. 12538-12547.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12538-12547
Mots-clés : System design Control system Process control Résumé : The emphasis on process economics in modem chemical plants has led to the increased use of material recycle and energy integration that significantly alter process dynamics and add complexity. As a result, many plantwide control (PWC) methodologies have emerged. However, there are very few comparative studies to evaluate the effectiveness of alternate methodologies. In this study, a PWC structure for the ammonia synthesis process is developed using the integrated framework of simulation and heuristics [Konda et al. Ind. Eng. Chem. Res. 2005, 44, 8300-8313], which is then compared with that developed by Araújo and Skogestad [Araújo and Skogestad, Comput. Chem. Eng. 2008, 32, 2920-2932] using the self-optimizing control procedure. The different control structures are evaluated in a comprehensive manner including assessment of the dynamic performance and steady-state profit. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692009 Exemplaires
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Titre : Turndown control structures for distillation columns Type de document : texte imprimé Auteurs : Patrick J. Robinson, Auteur ; William L. Luyben, Auteur Année de publication : 2011 Article en page(s) : pp. 12548–12559 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Distillation columns Résumé : Future chemical plants may be required to have much higher flexibility and agility than existing process facilities in order to be able to handle new hybrid combinations of power and chemical units. An important example is a gasification process producing synthesis gas that can either feed a combustion turbine for the generation of electricity or, during periods of lower power demand, feed a chemical plant. The chemical plant would be designed for the maximum capacity that is associated with periods of minimum electric power demand. But the plant would have to be able to turndown to low throughputs during periods of maximum electric power demand. The 24 h power demand swings in many locations can be a factor of 2 or more from day to night. The separations required in many chemical processes are achieved using distillation columns. If the process must operate over a wide range of throughputs, the columns must also have wide rangeability. There are several low-throughput limitations in distillation columns, usually involving hydraulic constraints. The most common is a low limit on vapor flow rate, below which weeping can adversely affect tray efficiency and separation. The vapor limit depends on tray design, with valve trays being the most rangeable. Even valve trays lose performance below about 50% of design vapor rates. If the plant throughput must be reduced to 25% of design capacity and the column vapor can only be reduced to 50% of design, a control structure that effectively handles this situation is required. The purpose of this paper is to explore three alternative control structures for columns with significant turndown requirements. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101945x
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12548–12559[article] Turndown control structures for distillation columns [texte imprimé] / Patrick J. Robinson, Auteur ; William L. Luyben, Auteur . - 2011 . - pp. 12548–12559.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12548–12559
Mots-clés : Distillation columns Résumé : Future chemical plants may be required to have much higher flexibility and agility than existing process facilities in order to be able to handle new hybrid combinations of power and chemical units. An important example is a gasification process producing synthesis gas that can either feed a combustion turbine for the generation of electricity or, during periods of lower power demand, feed a chemical plant. The chemical plant would be designed for the maximum capacity that is associated with periods of minimum electric power demand. But the plant would have to be able to turndown to low throughputs during periods of maximum electric power demand. The 24 h power demand swings in many locations can be a factor of 2 or more from day to night. The separations required in many chemical processes are achieved using distillation columns. If the process must operate over a wide range of throughputs, the columns must also have wide rangeability. There are several low-throughput limitations in distillation columns, usually involving hydraulic constraints. The most common is a low limit on vapor flow rate, below which weeping can adversely affect tray efficiency and separation. The vapor limit depends on tray design, with valve trays being the most rangeable. Even valve trays lose performance below about 50% of design vapor rates. If the plant throughput must be reduced to 25% of design capacity and the column vapor can only be reduced to 50% of design, a control structure that effectively handles this situation is required. The purpose of this paper is to explore three alternative control structures for columns with significant turndown requirements. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101945x Exemplaires
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Titre : Fabrication of bimodal porous CaTiO3 microspheres using composite agarose/CaCO3 beads as template Type de document : texte imprimé Auteurs : Kai-Feng Du, Auteur ; Xiao-Yan Dong, Auteur ; Yan Sun, Auteur Année de publication : 2011 Article en page(s) : pp. 12560–12566 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Microspheres Bimodal porous Résumé : Agarose gel entrapping CaCO3 granules is used for the synthesis of bimodal porous CaTiO3 beads by a method that combines a sol−gel process and solid phase reaction, in which CaCO3 (1.05 μm) performed as both calcium resource and porogen for creating macropores. The amount of CaCO3 granules embedded in agarose gel is varied from 0 to 16 wt %, and the macropores on the surface and in the inner of final CaTiO3 beads are investigated. It is found that the addition of 12 wt % of CaCO3 produced CaTiO3 beads that present interconnected macropores of about 745 ± 20 nm. The calcination temperature affects the surface area, mesopore size, phase state, and crystalline size of the CaTiO3 beads. By calcination at 450 °C, the CaTiO3 beads prepared by the addition of 12 wt % CaCO3 are amorphous with an average pore size of 9 nm and possess a high surface area of about 225 m2 g−1. With an increase of temperature to 600, 750, and 900 °C, the CaTiO3 is transformed into perovskite in size of about 32, 34, and 37 nm with mesopores of about 20, 23, and 24 nm, respectively, and its specific surface area decreases below 20 m2 g−1. The bimodal porous CaTiO3 beads of about 15 μm are packed into a column for investigating its chromatographic performance. The column shows much higher column efficiency than that packed with CaTiO3 beads without removal of the porogen. The remarkably high separation performance is attributed to the unique surface property and interconnected macropores present in the CaTiO3 beads. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901727s
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12560–12566[article] Fabrication of bimodal porous CaTiO3 microspheres using composite agarose/CaCO3 beads as template [texte imprimé] / Kai-Feng Du, Auteur ; Xiao-Yan Dong, Auteur ; Yan Sun, Auteur . - 2011 . - pp. 12560–12566.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12560–12566
Mots-clés : Microspheres Bimodal porous Résumé : Agarose gel entrapping CaCO3 granules is used for the synthesis of bimodal porous CaTiO3 beads by a method that combines a sol−gel process and solid phase reaction, in which CaCO3 (1.05 μm) performed as both calcium resource and porogen for creating macropores. The amount of CaCO3 granules embedded in agarose gel is varied from 0 to 16 wt %, and the macropores on the surface and in the inner of final CaTiO3 beads are investigated. It is found that the addition of 12 wt % of CaCO3 produced CaTiO3 beads that present interconnected macropores of about 745 ± 20 nm. The calcination temperature affects the surface area, mesopore size, phase state, and crystalline size of the CaTiO3 beads. By calcination at 450 °C, the CaTiO3 beads prepared by the addition of 12 wt % CaCO3 are amorphous with an average pore size of 9 nm and possess a high surface area of about 225 m2 g−1. With an increase of temperature to 600, 750, and 900 °C, the CaTiO3 is transformed into perovskite in size of about 32, 34, and 37 nm with mesopores of about 20, 23, and 24 nm, respectively, and its specific surface area decreases below 20 m2 g−1. The bimodal porous CaTiO3 beads of about 15 μm are packed into a column for investigating its chromatographic performance. The column shows much higher column efficiency than that packed with CaTiO3 beads without removal of the porogen. The remarkably high separation performance is attributed to the unique surface property and interconnected macropores present in the CaTiO3 beads. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901727s Exemplaires
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Titre : Adsorption of neodymium(III) from aqueous solutions using a phosphorus functionalized adsorbent Type de document : texte imprimé Auteurs : Hyung-Jun Park, Auteur ; Lawrence L. Tavlarides, Auteur Année de publication : 2011 Article en page(s) : pp. 12567–12575 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Adsorption neodymium Aqueous solutions Résumé : Separation of neodymium(III) from aqueous solutions is investigated using an phosphorus based sol−gel adsorbent. This adsorbent has been formed by the sol−gel synthesis method. The speciation diagram of Nd(III) in an aqueous phase with varying pH is studied by analyses of the equilibria equations. Batch adsorption equilibrium studies show an increase in neodymium uptake capacity with increase in pH in the range from pH 0.5 to pH 6.5, and the maximum uptake capacity at pH 6 is observed to be 1.13 mmol/g (160 mg/g). The equilibrium adsorption isotherm gives a satisfactory fit of the adsorption data. A kinetics study conducted with different concentrations and particle sizes of neodymium(III) in a batch reactor shows a high rate of adsorption. The adsorbent shows a capability of selectivity toward Nd(III) and other rare earths. Adsorption tests in a fixed bed column show a sharp breakthrough curve. Stripping of the neodymium-loaded column bed is achieved using 1 M HNO3. The material also has sustainable stability over repeated metal loading and stripping in a column. In addition to the experimental studies, the adsorption processes in batch and packed column systems are successfully modeled by using a pore diffusion model, and the results are presented. The organophosphorus functionalized adsorbent is demonstrated to be an effective sorbent material for the separation of neodymium(III) from aqueous solutions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100403b
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12567–12575[article] Adsorption of neodymium(III) from aqueous solutions using a phosphorus functionalized adsorbent [texte imprimé] / Hyung-Jun Park, Auteur ; Lawrence L. Tavlarides, Auteur . - 2011 . - pp. 12567–12575.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12567–12575
Mots-clés : Adsorption neodymium Aqueous solutions Résumé : Separation of neodymium(III) from aqueous solutions is investigated using an phosphorus based sol−gel adsorbent. This adsorbent has been formed by the sol−gel synthesis method. The speciation diagram of Nd(III) in an aqueous phase with varying pH is studied by analyses of the equilibria equations. Batch adsorption equilibrium studies show an increase in neodymium uptake capacity with increase in pH in the range from pH 0.5 to pH 6.5, and the maximum uptake capacity at pH 6 is observed to be 1.13 mmol/g (160 mg/g). The equilibrium adsorption isotherm gives a satisfactory fit of the adsorption data. A kinetics study conducted with different concentrations and particle sizes of neodymium(III) in a batch reactor shows a high rate of adsorption. The adsorbent shows a capability of selectivity toward Nd(III) and other rare earths. Adsorption tests in a fixed bed column show a sharp breakthrough curve. Stripping of the neodymium-loaded column bed is achieved using 1 M HNO3. The material also has sustainable stability over repeated metal loading and stripping in a column. In addition to the experimental studies, the adsorption processes in batch and packed column systems are successfully modeled by using a pore diffusion model, and the results are presented. The organophosphorus functionalized adsorbent is demonstrated to be an effective sorbent material for the separation of neodymium(III) from aqueous solutions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100403b Exemplaires
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Titre : Simultaneous capture of mercury and CO2 in amine - based CO2 absorption process Type de document : texte imprimé Auteurs : Zheng Cui, Auteur ; Adisorn Aroonwilas, Auteur ; Amornvadee Veawab, Auteur Année de publication : 2011 Article en page(s) : pp. 12576–12586 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Absorption Process Résumé : The feasibility of using an amine-based carbon dioxide (CO2) capture unit for the simultaneous capture of mercury (Hg) and CO2 was studied by carrying out Hg absorption experiments with three different types of absorption solutions: mixtures of sodium chloride (NaCl) and sodium hypochlorite (NaOCl), monoethanolamine (MEA), and blended MEA and NaCl/NaOCl. The results show that it is not effective to use the amine-based CO2 unit for the concurrent capture of Hg and CO2 because the Hg absorption performance of aqueous solutions of MEA and blended MEA/NaCl/NaOCl is low. Mixtures of NaOCl and NaCl do not perform as a rate enhancer for Hg removal in the presence of MEA. The presence of Hg in the MEA solutions does not affect the CO2 absorption performance of MEA. To capture both Hg and CO2, a two-step capture process that employs an aqueous NaCl/NaOCl solution for Hg removal, prior to CO2 capture in the amine unit, might be an option. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100687a
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12576–12586[article] Simultaneous capture of mercury and CO2 in amine - based CO2 absorption process [texte imprimé] / Zheng Cui, Auteur ; Adisorn Aroonwilas, Auteur ; Amornvadee Veawab, Auteur . - 2011 . - pp. 12576–12586.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12576–12586
Mots-clés : Absorption Process Résumé : The feasibility of using an amine-based carbon dioxide (CO2) capture unit for the simultaneous capture of mercury (Hg) and CO2 was studied by carrying out Hg absorption experiments with three different types of absorption solutions: mixtures of sodium chloride (NaCl) and sodium hypochlorite (NaOCl), monoethanolamine (MEA), and blended MEA and NaCl/NaOCl. The results show that it is not effective to use the amine-based CO2 unit for the concurrent capture of Hg and CO2 because the Hg absorption performance of aqueous solutions of MEA and blended MEA/NaCl/NaOCl is low. Mixtures of NaOCl and NaCl do not perform as a rate enhancer for Hg removal in the presence of MEA. The presence of Hg in the MEA solutions does not affect the CO2 absorption performance of MEA. To capture both Hg and CO2, a two-step capture process that employs an aqueous NaCl/NaOCl solution for Hg removal, prior to CO2 capture in the amine unit, might be an option. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100687a Exemplaires
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Titre : Effect of the acid treatment of olive stone on the biosorption of lead in a packed - bed column Type de document : texte imprimé Auteurs : Monica Calero de Hoces, Auteur ; Gabriel Blazquez Garcia, Auteur ; Alicia Ronda Galvez, Auteur Année de publication : 2011 Article en page(s) : pp. 12587–12595 Note générale : Chimie industrielle Mots-clés : Biosorption Résumé : Biosorption of lead(II) ions from aqueous solutions by untreated, HCl-treated, H2SO4-treated, HNO3-treated, and H3PO4-treated olive stone was studied in a continuous-upflow packed-bed column. The effect of acid treatment on the lead biosorption capacity of olive stone was determined by evaluating the breakthrough curves obtained at different inlet concentrations of lead, changing from 10 to 150 mg/L. Results indicated that the treatment of olive stone with inorganic acids improves significantly its capacity to removal lead ions from aqueous solution. Finally, the Adams−Bohart, Thomas, Yoon and Nelson, and dose−response models were used to analyze the experimental data to determine the characteristic parameters of the column useful for process design. In particular, the dose−response model was able to simulate breakthrough curves at lower and higher time periods with high correlation coefficients. The maximum column biosorption capacity predicted by this model at an inlet lead concentration of 150 mg/L was 1.31 mg/g for unmodified olive stone and 14.03 mg/g for olive stone treated by H2SO4. Also, the pH variations during the sorption process have been reported. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1013597
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12587–12595[article] Effect of the acid treatment of olive stone on the biosorption of lead in a packed - bed column [texte imprimé] / Monica Calero de Hoces, Auteur ; Gabriel Blazquez Garcia, Auteur ; Alicia Ronda Galvez, Auteur . - 2011 . - pp. 12587–12595.
Chimie industrielle
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12587–12595
Mots-clés : Biosorption Résumé : Biosorption of lead(II) ions from aqueous solutions by untreated, HCl-treated, H2SO4-treated, HNO3-treated, and H3PO4-treated olive stone was studied in a continuous-upflow packed-bed column. The effect of acid treatment on the lead biosorption capacity of olive stone was determined by evaluating the breakthrough curves obtained at different inlet concentrations of lead, changing from 10 to 150 mg/L. Results indicated that the treatment of olive stone with inorganic acids improves significantly its capacity to removal lead ions from aqueous solution. Finally, the Adams−Bohart, Thomas, Yoon and Nelson, and dose−response models were used to analyze the experimental data to determine the characteristic parameters of the column useful for process design. In particular, the dose−response model was able to simulate breakthrough curves at lower and higher time periods with high correlation coefficients. The maximum column biosorption capacity predicted by this model at an inlet lead concentration of 150 mg/L was 1.31 mg/g for unmodified olive stone and 14.03 mg/g for olive stone treated by H2SO4. Also, the pH variations during the sorption process have been reported. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1013597 Exemplaires
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Titre : Prediction of the phase behavior of Ionic liquid solutions Type de document : texte imprimé Auteurs : Li Yang, Auteur ; Stanley I. Sandler, Auteur ; Changjun Peng, Auteur Année de publication : 2011 Article en page(s) : pp. 12596-12604 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ionic liquid Prediction Résumé : Here we examine the application of the COSMO-SAC model to phase equilibrium calculations of solutions containing ionic liquids (ILs). As there is uncertainty about the degree of ionization in these liquids, we consider three methods: treating the IL as a neutral molecule, as a separated anion and cation, and essentially as an ion pair. In the first case, the needed quantum mechanics calculation is done for the neutral molecule referred to as COSMO-SAC(molecule), and in the other two cases, the calculations are performed for the separated ions in which the IL is treated as two separate components, COSMO-SAC(ions) or COSMO-SAC(CA), in which the separate cosmo files are combined and the IL is treated as a single-component neutral ion pair. There is generally good agreement between the predicted results and the experimental data using COSMO-SAC(CA) and COSMO-SAC(ions), while for COSMO-SAC(molecule) the results are less satisfactory and the calculations are more difficult because of the problems with geometry optimization and the density functional calculations for the large intact IL molecules. The results show that the COSMO-SAC model can give reasonably good predictions for the vapor—liquid equilibria, liquid—liquid equilibria, and infinite dilution activity coefficients for solutions containing ionic liquids. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692015
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12596-12604[article] Prediction of the phase behavior of Ionic liquid solutions [texte imprimé] / Li Yang, Auteur ; Stanley I. Sandler, Auteur ; Changjun Peng, Auteur . - 2011 . - pp. 12596-12604.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12596-12604
Mots-clés : Ionic liquid Prediction Résumé : Here we examine the application of the COSMO-SAC model to phase equilibrium calculations of solutions containing ionic liquids (ILs). As there is uncertainty about the degree of ionization in these liquids, we consider three methods: treating the IL as a neutral molecule, as a separated anion and cation, and essentially as an ion pair. In the first case, the needed quantum mechanics calculation is done for the neutral molecule referred to as COSMO-SAC(molecule), and in the other two cases, the calculations are performed for the separated ions in which the IL is treated as two separate components, COSMO-SAC(ions) or COSMO-SAC(CA), in which the separate cosmo files are combined and the IL is treated as a single-component neutral ion pair. There is generally good agreement between the predicted results and the experimental data using COSMO-SAC(CA) and COSMO-SAC(ions), while for COSMO-SAC(molecule) the results are less satisfactory and the calculations are more difficult because of the problems with geometry optimization and the density functional calculations for the large intact IL molecules. The results show that the COSMO-SAC model can give reasonably good predictions for the vapor—liquid equilibria, liquid—liquid equilibria, and infinite dilution activity coefficients for solutions containing ionic liquids. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692015 Exemplaires
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Titre : Mixed - matrix membrane hollow fibers of Cu3(BTC)2 MOF and polyimide for gas separation and adsorption Type de document : texte imprimé Auteurs : Jun Hu, Auteur ; Hongpei Cai, Auteur ; Huiqing Ren, Auteur Année de publication : 2011 Article en page(s) : pp. 12605-12612 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Adsorption Hollow fiber Résumé : Metal-organic framework (MOF) crystals of Cu3(BTC)2 with a high surface area (1396 m2·g-1) were synthesized and mixed with polyimide (PI) to prepare mixed-matrix membranes (MMMs) for gas separations. The PI-Cu3(BTC)2 blend was successfully spun into MMM hollow fiber by the dry/wet-spinning method. SEM images of the fiber cross sections revealed significant plastic deformation of the polymer matrix owing to the strong affinity between Cu3(BTC)2 and PI. The H2 permeance and the selectivity of H2 with respect to other gases such as N2, CO2, O2, and CH4 both increased markedly with increased Cu3(BTC)2 loading. At a loading of 6 wt % Cu3(BTC)2, the permeance of H2 increased by 45%, and the ideal selectivity increased by a factor of 2—3 compared to the corresponding values for pure PI. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692016
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12605-12612[article] Mixed - matrix membrane hollow fibers of Cu3(BTC)2 MOF and polyimide for gas separation and adsorption [texte imprimé] / Jun Hu, Auteur ; Hongpei Cai, Auteur ; Huiqing Ren, Auteur . - 2011 . - pp. 12605-12612.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12605-12612
Mots-clés : Adsorption Hollow fiber Résumé : Metal-organic framework (MOF) crystals of Cu3(BTC)2 with a high surface area (1396 m2·g-1) were synthesized and mixed with polyimide (PI) to prepare mixed-matrix membranes (MMMs) for gas separations. The PI-Cu3(BTC)2 blend was successfully spun into MMM hollow fiber by the dry/wet-spinning method. SEM images of the fiber cross sections revealed significant plastic deformation of the polymer matrix owing to the strong affinity between Cu3(BTC)2 and PI. The H2 permeance and the selectivity of H2 with respect to other gases such as N2, CO2, O2, and CH4 both increased markedly with increased Cu3(BTC)2 loading. At a loading of 6 wt % Cu3(BTC)2, the permeance of H2 increased by 45%, and the ideal selectivity increased by a factor of 2—3 compared to the corresponding values for pure PI. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692016 Exemplaires
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Titre : Liquid - liquid equilibrium for ternary systems containing ethyl esters, anhydrous ethanol and water at 298.15, 313.15, and 333.15 K Type de document : texte imprimé Auteurs : Luis A. Follegatti-Romero, Auteur ; Marcelo Lanza, Auteur ; Fabio R. M. Batista, Auteur Année de publication : 2011 Article en page(s) : pp. 12613–12619 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ternary system Phase equilibrium Liquid liquid Résumé : The most common method used for purifying biodiesel is washing with water. During the biodiesel washing process, two phases are formed, a water-rich phase and an ester-rich one. For this reason, knowledge of the corresponding phase equilibrium is an important step in optimizing the final purification of biodiesel. The objective of this work was to investigate the liquid−liquid equilibrium related to some esters of interest in the production of ethylic biodiesel, in particular the equilibrium data for systems containing ethyl laurate/ethyl myristate + ethanol + water at 298.15, 313.15, and 333.15 K. The data obtained were correlated with the cubic-plus-association equation of state (CPA EoS). It was shown that this model was able to provide a very good description of the phase diagrams of the systems studied. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692017
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12613–12619[article] Liquid - liquid equilibrium for ternary systems containing ethyl esters, anhydrous ethanol and water at 298.15, 313.15, and 333.15 K [texte imprimé] / Luis A. Follegatti-Romero, Auteur ; Marcelo Lanza, Auteur ; Fabio R. M. Batista, Auteur . - 2011 . - pp. 12613–12619.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12613–12619
Mots-clés : Ternary system Phase equilibrium Liquid liquid Résumé : The most common method used for purifying biodiesel is washing with water. During the biodiesel washing process, two phases are formed, a water-rich phase and an ester-rich one. For this reason, knowledge of the corresponding phase equilibrium is an important step in optimizing the final purification of biodiesel. The objective of this work was to investigate the liquid−liquid equilibrium related to some esters of interest in the production of ethylic biodiesel, in particular the equilibrium data for systems containing ethyl laurate/ethyl myristate + ethanol + water at 298.15, 313.15, and 333.15 K. The data obtained were correlated with the cubic-plus-association equation of state (CPA EoS). It was shown that this model was able to provide a very good description of the phase diagrams of the systems studied. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692017 Exemplaires
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Titre : Enhancement of particle collection efficiency in electrohydrodynamic atomization process for pharmaceutical particle fabrication Type de document : texte imprimé Auteurs : Alireza Rezvanpour, Auteur ; Amalina B. E. Attia, Auteur ; Chi-Hwa Wang, Auteur Année de publication : 2011 Article en page(s) : pp. 12620-12631 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Electrohydrodynamics Particle collection Résumé : In the present work, Electrohydrodynamic Atomization was employed to produce biodegradable polymeri microparticles in a new generation of shuttle glass chamber. The effects of different parameters including solution flow rate, nitrogen flow rate, nozzle, and ring voltage on the particle collection efficiency and residua amount of organic solvent in collected particles were investigated systematically. The Taguchi (a combine DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692018
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12620-12631[article] Enhancement of particle collection efficiency in electrohydrodynamic atomization process for pharmaceutical particle fabrication [texte imprimé] / Alireza Rezvanpour, Auteur ; Amalina B. E. Attia, Auteur ; Chi-Hwa Wang, Auteur . - 2011 . - pp. 12620-12631.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12620-12631
Mots-clés : Electrohydrodynamics Particle collection Résumé : In the present work, Electrohydrodynamic Atomization was employed to produce biodegradable polymeri microparticles in a new generation of shuttle glass chamber. The effects of different parameters including solution flow rate, nitrogen flow rate, nozzle, and ring voltage on the particle collection efficiency and residua amount of organic solvent in collected particles were investigated systematically. The Taguchi (a combine DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692018 Exemplaires
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Titre : Preparation of spherical ammonium nitrate particles by melt spray Type de document : texte imprimé Auteurs : Jae-Kyeong Kim, Auteur ; Seung-Il Choi, Auteur ; Eui Jung Kim, Auteur Année de publication : 2011 Article en page(s) : pp. 12632-12637 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Preparation Spherical ammonium Résumé : Spherical ammonium nitrate particles with average diameters of 82-206 μm were produced using the mel spray system built in the present work. The effects of spray pressure and temperature on the size distribution and average diameter of the ammonium nitrate particles were investigated. It was found that increasing the spray pressure at given temperature or increasing the temperature at given pressure enhanced the disintegration of the front edge of the liquid sheet into fine droplets and, thus, slightly reduced the average diameter of the ammonium nitrate particles. X-ray diffraction patterns confirmed all spherical ammonium nitrate particles to be form IV because of a rapid phase transition from form I to form IV. Dombrowski and Johns' equation which is applicable to highly viscous spray fluids, was found to be satisfactory for estimating the Saute diameter of the ammonium nitrate particles. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692019
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12632-12637[article] Preparation of spherical ammonium nitrate particles by melt spray [texte imprimé] / Jae-Kyeong Kim, Auteur ; Seung-Il Choi, Auteur ; Eui Jung Kim, Auteur . - 2011 . - pp. 12632-12637.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12632-12637
Mots-clés : Preparation Spherical ammonium Résumé : Spherical ammonium nitrate particles with average diameters of 82-206 μm were produced using the mel spray system built in the present work. The effects of spray pressure and temperature on the size distribution and average diameter of the ammonium nitrate particles were investigated. It was found that increasing the spray pressure at given temperature or increasing the temperature at given pressure enhanced the disintegration of the front edge of the liquid sheet into fine droplets and, thus, slightly reduced the average diameter of the ammonium nitrate particles. X-ray diffraction patterns confirmed all spherical ammonium nitrate particles to be form IV because of a rapid phase transition from form I to form IV. Dombrowski and Johns' equation which is applicable to highly viscous spray fluids, was found to be satisfactory for estimating the Saute diameter of the ammonium nitrate particles. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692019 Exemplaires
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Titre : Pre - extraction of hemicelluloses from hardwood chips using an alkaline wood pulping solution followed by kraft pulping of the extracted wood chips Type de document : texte imprimé Auteurs : Sara L. Walton, Auteur ; Dwane Hutto, Auteur ; Joseph M. Genco, Auteur Année de publication : 2011 Article en page(s) : pp.12638–12645 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hemicelluloses Wood Résumé : Mixed southern hardwood chips were extracted with an alkaline wood pulping solution called kraft green liquor. This aqueous solution containing mainly sodium carbonate and sodium sulfide was applied at different alkali charges (expressed as Na2O) of 0, 2, 4, and 6% on dry wood weight. The extractions were performed at 160 °C for effective times ranging from about 1−2 h to determine the effect of extraction severity on pulp yield and composition of the extracted liquor. The severity of hemicellulose extraction time and alkaline charge controls the concentration of acetic acid and monosaccharide sugars available for downstream processing, the accumulation of degradation products such as organic acids and furans in the extract, and the pulp yield attainable for the extracted wood chips. As the alkali charge was increased, the amount of acetate side chains on the hemicelluloses and the dissolved lignin in the extract increased but the carbohydrate and sugars in the extract decreased appreciably. Water extraction (0% alkali addition) released the greatest amount of carbohydrates, up to 30 g/L measured as component sugars, but resulted in the greatest decrease in pulp yield, dropping from 47% to 35%. Extraction with 2% green liquor increased the pulp yield to 51% while greatly reducing the component sugars to 8 g/L. Data obtained in this work will allow selection of optimum hemicellulose extraction conditions for integrating the extraction operation into the Kraft pulping process. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100848p
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp.12638–12645[article] Pre - extraction of hemicelluloses from hardwood chips using an alkaline wood pulping solution followed by kraft pulping of the extracted wood chips [texte imprimé] / Sara L. Walton, Auteur ; Dwane Hutto, Auteur ; Joseph M. Genco, Auteur . - 2011 . - pp.12638–12645.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp.12638–12645
Mots-clés : Hemicelluloses Wood Résumé : Mixed southern hardwood chips were extracted with an alkaline wood pulping solution called kraft green liquor. This aqueous solution containing mainly sodium carbonate and sodium sulfide was applied at different alkali charges (expressed as Na2O) of 0, 2, 4, and 6% on dry wood weight. The extractions were performed at 160 °C for effective times ranging from about 1−2 h to determine the effect of extraction severity on pulp yield and composition of the extracted liquor. The severity of hemicellulose extraction time and alkaline charge controls the concentration of acetic acid and monosaccharide sugars available for downstream processing, the accumulation of degradation products such as organic acids and furans in the extract, and the pulp yield attainable for the extracted wood chips. As the alkali charge was increased, the amount of acetate side chains on the hemicelluloses and the dissolved lignin in the extract increased but the carbohydrate and sugars in the extract decreased appreciably. Water extraction (0% alkali addition) released the greatest amount of carbohydrates, up to 30 g/L measured as component sugars, but resulted in the greatest decrease in pulp yield, dropping from 47% to 35%. Extraction with 2% green liquor increased the pulp yield to 51% while greatly reducing the component sugars to 8 g/L. Data obtained in this work will allow selection of optimum hemicellulose extraction conditions for integrating the extraction operation into the Kraft pulping process. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100848p Exemplaires
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Titre : A heuristic - embedded scheduling system for a pharmaceutical intermediates manufacturing plant Type de document : texte imprimé Auteurs : Jiyong Kim, Auteur ; Junghwan Kim, Auteur ; Taeyeong Lee, Auteur Année de publication : 2011 Article en page(s) : pp. 12646-12653 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Manufacturing Scheduling Résumé : This paper proposes a new mathematical model for a real pharmaceutical intermediates manufacturing (PIM plant. To consider the general characteristics of the scheduling problems experienced at PIM plants, the propose model employed a strategy to address a mixed-integer linear programming (MILP) formulation. Two heuristi techniques—preclassification of equipment and sequential two-stage optimization-were then proposed, to relax the complexities of scheduling problems that are due to practical constraints. The objective function the proposed model is to minimize the total operation time (makespan) that is subject to the mass balance constraints and process boundary conditions. On the basis of the proposed models and heuristics, new package software is developed for an application to real PIM plants. To show the features and capabilities of th proposed scheduling system, four real examples were examined. The results reveal that the techniques ar helpful for obtaining both higher accuracy of optimized solutions and higher computational performance. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692021
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12646-12653[article] A heuristic - embedded scheduling system for a pharmaceutical intermediates manufacturing plant [texte imprimé] / Jiyong Kim, Auteur ; Junghwan Kim, Auteur ; Taeyeong Lee, Auteur . - 2011 . - pp. 12646-12653.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12646-12653
Mots-clés : Manufacturing Scheduling Résumé : This paper proposes a new mathematical model for a real pharmaceutical intermediates manufacturing (PIM plant. To consider the general characteristics of the scheduling problems experienced at PIM plants, the propose model employed a strategy to address a mixed-integer linear programming (MILP) formulation. Two heuristi techniques—preclassification of equipment and sequential two-stage optimization-were then proposed, to relax the complexities of scheduling problems that are due to practical constraints. The objective function the proposed model is to minimize the total operation time (makespan) that is subject to the mass balance constraints and process boundary conditions. On the basis of the proposed models and heuristics, new package software is developed for an application to real PIM plants. To show the features and capabilities of th proposed scheduling system, four real examples were examined. The results reveal that the techniques ar helpful for obtaining both higher accuracy of optimized solutions and higher computational performance. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692021 Exemplaires
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Titre : Process control and investigation of oxidation kinetics of postoxidative effluents using gas chromatography with pulsed flame photometric detection (GC - PFPD) Type de document : texte imprimé Auteurs : Grzegorz Boczkaj, Auteur ; Marian Kaminski, Auteur ; Andrzej Przyjazny, Auteur Année de publication : 2011 Article en page(s) : pp. 12654–12662 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetics Résumé : This article presents the results of investigations on the use of headspace analysis and gas chromatography with pulsed flame photometric detection (HSA-GC-PFPD) to evaluate the effectiveness of oxidation of postoxidative effluents from the production of bitumens. Samples of effluents from the bitumen oxidation unit were used in the experiments. In addition, the kinetics of effluent oxidation was also investigated. The content of volatile sulfur compounds (VSCs) was determined using HSA-GC-PFPD. The results were correlated with chemical oxygen demand (COD). The changes in concentration of individual volatile sulfur compounds in the course of effluent oxidation were measured, which enabled the determination of the order of the oxidation reactions. The usefulness of the determination of VSCs in the headspace as a reliable technique for evaluating the reduction in emissions of volatile malodorous compounds was demonstrated. The developed method is also useful for process control of the oxidation of postoxidative effluents. The procedure ensures an objective evaluation of the effectiveness of the removal of volatile sulfur compounds from postoxidative effluents. The experimental results revealed that the effectiveness of the oxidation of organosulfur compounds was much higher than that of other classes of organic compounds. Furthermore, the order of oxidation reactions along with the rate constants of thiophenol, p-thiocresol, and hydrogen sulfide were determined. An advantage of the developed procedure is that it can be automated. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100939x
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12654–12662[article] Process control and investigation of oxidation kinetics of postoxidative effluents using gas chromatography with pulsed flame photometric detection (GC - PFPD) [texte imprimé] / Grzegorz Boczkaj, Auteur ; Marian Kaminski, Auteur ; Andrzej Przyjazny, Auteur . - 2011 . - pp. 12654–12662.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12654–12662
Mots-clés : Kinetics Résumé : This article presents the results of investigations on the use of headspace analysis and gas chromatography with pulsed flame photometric detection (HSA-GC-PFPD) to evaluate the effectiveness of oxidation of postoxidative effluents from the production of bitumens. Samples of effluents from the bitumen oxidation unit were used in the experiments. In addition, the kinetics of effluent oxidation was also investigated. The content of volatile sulfur compounds (VSCs) was determined using HSA-GC-PFPD. The results were correlated with chemical oxygen demand (COD). The changes in concentration of individual volatile sulfur compounds in the course of effluent oxidation were measured, which enabled the determination of the order of the oxidation reactions. The usefulness of the determination of VSCs in the headspace as a reliable technique for evaluating the reduction in emissions of volatile malodorous compounds was demonstrated. The developed method is also useful for process control of the oxidation of postoxidative effluents. The procedure ensures an objective evaluation of the effectiveness of the removal of volatile sulfur compounds from postoxidative effluents. The experimental results revealed that the effectiveness of the oxidation of organosulfur compounds was much higher than that of other classes of organic compounds. Furthermore, the order of oxidation reactions along with the rate constants of thiophenol, p-thiocresol, and hydrogen sulfide were determined. An advantage of the developed procedure is that it can be automated. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100939x Exemplaires
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Titre : Modeling of carbon dioxide absorption by aqueous ammonia solutions using the extended UNIQUAC model Type de document : texte imprimé Auteurs : Victor Darde, Auteur ; Willy J. M. Van Well, Auteur ; Erling H. Stenby, Auteur Année de publication : 2011 Article en page(s) : pp. 12663-12674 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Gas absorption Carbon dioxide Modeling Résumé : An upgraded version of the extended UNIQUAC thermodynamic model for the carbon dioxide-ammonia-water system has been developed, on the basis of the original version proposed by Thomsen and Rasmussen (Chem. Eng. Sci. 1999, 54, 1787). The original model was valid in the temperature range 0-110 °C, the pressure range 0-10 MPa, and the concentration range up to 80 m ammonia. In this work, the validity of this model was extended up to 150 °C and the accuracy improved by increasing the number of experimental data points from 2000 to more than 3700. These experimental data consisting of vapor-liquid equilibrium data in various concentration ranges, enthalpy change from partial evaporation measurements, speciation data, heat capacity, enthalpy of solution, and enthalpy of dilution data have been used to refit 43 model parameters and standard-state properties. Henry's law constant correlations have been used for extrapolating standard-state properties of carbon dioxide and ammonia to supercritical conditions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692023
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12663-12674[article] Modeling of carbon dioxide absorption by aqueous ammonia solutions using the extended UNIQUAC model [texte imprimé] / Victor Darde, Auteur ; Willy J. M. Van Well, Auteur ; Erling H. Stenby, Auteur . - 2011 . - pp. 12663-12674.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12663-12674
Mots-clés : Gas absorption Carbon dioxide Modeling Résumé : An upgraded version of the extended UNIQUAC thermodynamic model for the carbon dioxide-ammonia-water system has been developed, on the basis of the original version proposed by Thomsen and Rasmussen (Chem. Eng. Sci. 1999, 54, 1787). The original model was valid in the temperature range 0-110 °C, the pressure range 0-10 MPa, and the concentration range up to 80 m ammonia. In this work, the validity of this model was extended up to 150 °C and the accuracy improved by increasing the number of experimental data points from 2000 to more than 3700. These experimental data consisting of vapor-liquid equilibrium data in various concentration ranges, enthalpy change from partial evaporation measurements, speciation data, heat capacity, enthalpy of solution, and enthalpy of dilution data have been used to refit 43 model parameters and standard-state properties. Henry's law constant correlations have been used for extrapolating standard-state properties of carbon dioxide and ammonia to supercritical conditions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692023 Exemplaires
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Titre : Synthesis and characterization of novel poly (N - isopropylacrylamide - co - N,N' - dimethylaminoethyl methacrylate sulfate) hydrogels Type de document : texte imprimé Auteurs : Gulten Gurdag, Auteur ; Bestenur Kurtulus, Auteur Année de publication : 2011 Article en page(s) : pp. 12675-12684 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydrogels Résumé : Poly(N-isopropylacrylamide-co-N,N'-dimethylaminoethyl methacrylate sulfate) [P(NIPAM-co-DMAEMASA)] was prepared from N-isopropylacrylamide (NIPAM) and N,N-dimethylaminoethyl methacrylate sulfate (DMAEMASA) monomers, and its properties were compared with those of poly(N-isopropylacrylamide-co-N,N'-dimethylaminoethyl methacrylate) [P(NIPAM-co-DMAEMA)]. The copolymers were characterized by swelling measurements in distilled water (10-40 °C) and buffer solutions (I = 0.1 M, pH = 2.2-10.0), FTIR, DSC, and SEM methods. The ESV's of the NIPAM-DMAEMASA copolymers in distilled water were 5 times higher than those of P(NIPAM-co-DMAEMA); they decreased with an increase in comonomer (DMAEMASA/DMAEMA) content for both copolymers. While NIPAM-DMAEMASA copolymers did not display any phase transition with temperature, the LCST of the NIPAM-DMAEMA copolymer was determined as 20 °C. Both copolymers displayed a phase transition at pH = 5.0, but the pH of the phase transition for NIPAM-DMAEMA gels shifted to 7.0 with increased DMAEMA content. Glass transition temperatures of NIPAM copolymers did not change with the type and content of comonomer. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692024
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12675-12684[article] Synthesis and characterization of novel poly (N - isopropylacrylamide - co - N,N' - dimethylaminoethyl methacrylate sulfate) hydrogels [texte imprimé] / Gulten Gurdag, Auteur ; Bestenur Kurtulus, Auteur . - 2011 . - pp. 12675-12684.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12675-12684
Mots-clés : Hydrogels Résumé : Poly(N-isopropylacrylamide-co-N,N'-dimethylaminoethyl methacrylate sulfate) [P(NIPAM-co-DMAEMASA)] was prepared from N-isopropylacrylamide (NIPAM) and N,N-dimethylaminoethyl methacrylate sulfate (DMAEMASA) monomers, and its properties were compared with those of poly(N-isopropylacrylamide-co-N,N'-dimethylaminoethyl methacrylate) [P(NIPAM-co-DMAEMA)]. The copolymers were characterized by swelling measurements in distilled water (10-40 °C) and buffer solutions (I = 0.1 M, pH = 2.2-10.0), FTIR, DSC, and SEM methods. The ESV's of the NIPAM-DMAEMASA copolymers in distilled water were 5 times higher than those of P(NIPAM-co-DMAEMA); they decreased with an increase in comonomer (DMAEMASA/DMAEMA) content for both copolymers. While NIPAM-DMAEMASA copolymers did not display any phase transition with temperature, the LCST of the NIPAM-DMAEMA copolymer was determined as 20 °C. Both copolymers displayed a phase transition at pH = 5.0, but the pH of the phase transition for NIPAM-DMAEMA gels shifted to 7.0 with increased DMAEMA content. Glass transition temperatures of NIPAM copolymers did not change with the type and content of comonomer. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692024 Exemplaires
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Titre : A new Neural network group contribution method for estimation of upper flash point of pure chemicals Type de document : texte imprimé Auteurs : Farhad Gharagheizi, Auteur ; Reza Abbasi, Auteur Année de publication : 2011 Article en page(s) : pp. 12685-12695 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Group contribution method Neural network Résumé : In this study, a new group contribution-based model is presented for the prediction of the upper flash point temperature of pure compounds based on a large data set containing 1294 pure compounds. The model is a neural network using a number of occurrences of 122 chemical groups in a pure compound to predict its related UFLT (Upper Flash Point Limit). The squared correlation coefficient, average percent error, mean average error, and root-mean-square error of the model over the main data set containing 1294 pure compounds are 0.99, 1.7%, 6, and 8.5, respectively. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692025
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12685-12695[article] A new Neural network group contribution method for estimation of upper flash point of pure chemicals [texte imprimé] / Farhad Gharagheizi, Auteur ; Reza Abbasi, Auteur . - 2011 . - pp. 12685-12695.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12685-12695
Mots-clés : Group contribution method Neural network Résumé : In this study, a new group contribution-based model is presented for the prediction of the upper flash point temperature of pure compounds based on a large data set containing 1294 pure compounds. The model is a neural network using a number of occurrences of 122 chemical groups in a pure compound to predict its related UFLT (Upper Flash Point Limit). The squared correlation coefficient, average percent error, mean average error, and root-mean-square error of the model over the main data set containing 1294 pure compounds are 0.99, 1.7%, 6, and 8.5, respectively. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692025 Exemplaires
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Titre : Critical - point temperature of ionic liquids from surface tension at liquid — vapor equilibrium and the correlation with the interaction energy Type de document : texte imprimé Auteurs : Mohammad Hadi Ghatee, Auteur ; Fatemeh Moosavi, Auteur ; Amin Reza Zolghadr, Auteur Année de publication : 2011 Article en page(s) : pp. 12696-12701 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Correlation analysis Phase equilibrium Liquid vapor Surface tension Ionic liquid Critical point Résumé : The critical temperature of ionic liquids is predicted by scaling-law, Guggenheim, and Eötvös approaches using surface tension data measured in the temperature range of 293-393 K. The available surface tensior data for imidazolium-, phosphonium-, and ammonium-based ionic liquids, with different anions content, show that the predicted critical temperature is a function of cation type and its alkyl chain length as well as the anion type. According to this dependence on the nature of the ionic liquid, the anion-cation interactior energy (Einter) was calculated by quantum mechanical density functional theory and the correlation with the predicted critical temperature was studied. The predicted critical temperature has a direct correlation to the absolute value of Einter. The ionic liquids with the BF4- anion, which consistently have the highest critica point temperature, also have the largest absolute value of Einter. As the alkyl chain length increases, the critica temperature decreases. When the surface tension is measured under a liquid-vapor equilibrium, the prediction has the meaningful feature of producing the critical-point temperature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692026
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12696-12701[article] Critical - point temperature of ionic liquids from surface tension at liquid — vapor equilibrium and the correlation with the interaction energy [texte imprimé] / Mohammad Hadi Ghatee, Auteur ; Fatemeh Moosavi, Auteur ; Amin Reza Zolghadr, Auteur . - 2011 . - pp. 12696-12701.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12696-12701
Mots-clés : Correlation analysis Phase equilibrium Liquid vapor Surface tension Ionic liquid Critical point Résumé : The critical temperature of ionic liquids is predicted by scaling-law, Guggenheim, and Eötvös approaches using surface tension data measured in the temperature range of 293-393 K. The available surface tensior data for imidazolium-, phosphonium-, and ammonium-based ionic liquids, with different anions content, show that the predicted critical temperature is a function of cation type and its alkyl chain length as well as the anion type. According to this dependence on the nature of the ionic liquid, the anion-cation interactior energy (Einter) was calculated by quantum mechanical density functional theory and the correlation with the predicted critical temperature was studied. The predicted critical temperature has a direct correlation to the absolute value of Einter. The ionic liquids with the BF4- anion, which consistently have the highest critica point temperature, also have the largest absolute value of Einter. As the alkyl chain length increases, the critica temperature decreases. When the surface tension is measured under a liquid-vapor equilibrium, the prediction has the meaningful feature of producing the critical-point temperature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692026 Exemplaires
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Titre : Prediction of flash point of organosilicon compounds using quantitative structure property relationship approach Type de document : texte imprimé Auteurs : Chan-Cheng Chen, Auteur ; Horng-Jang Liaw, Auteur ; Yi-Jen Tsai, Auteur Année de publication : 2011 Article en page(s) : pp. 12702–12708 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Organosilicon compounds Résumé : Flash point (FP) is the primary property to classify flammable liquids for the purpose of assessing their fire and explosion hazards. Because of the advancement of technology in discovering or synthesizing new compounds, there is often a significant gap between the demand for such data and their availability. In this regard, reliable methods to estimate the FP of a compound are indispensible. In this work, a quantitative structure property relationship study is presented for predicting the FP of organosilicon compounds. To build up and validate the proposed models, a data set of 230 organosilicon compounds are collected and divided into a training set of 184 compounds and a testing set of 46 compounds. The stepwise regression method is used to select the required molecular descriptors for predicting the FP of organosilicon compounds from 1538 molecular descriptors. Depending on the p-value for accepting a descriptor to enter the model, models with different number of descriptors are obtained. A 13-descriptor model and a 6-descriptor model are obtained with the p-value of 5 × 10−4 and 1 × 10−5, respectively. It is found that the 6-descriptor model could fit the training data with R2 = 0.8981 and predict the test data with Q2 = 0.8533 and the 13-descriptor model could fit the training data with R2 = 0.9293 and predict the test data with Q2 = 0.9245. The average predictive errors are less than 5% for both proposed models and they are useful for many practical applications, because the proposed models used only calculated descriptors from the molecular structure. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101381b
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12702–12708[article] Prediction of flash point of organosilicon compounds using quantitative structure property relationship approach [texte imprimé] / Chan-Cheng Chen, Auteur ; Horng-Jang Liaw, Auteur ; Yi-Jen Tsai, Auteur . - 2011 . - pp. 12702–12708.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12702–12708
Mots-clés : Organosilicon compounds Résumé : Flash point (FP) is the primary property to classify flammable liquids for the purpose of assessing their fire and explosion hazards. Because of the advancement of technology in discovering or synthesizing new compounds, there is often a significant gap between the demand for such data and their availability. In this regard, reliable methods to estimate the FP of a compound are indispensible. In this work, a quantitative structure property relationship study is presented for predicting the FP of organosilicon compounds. To build up and validate the proposed models, a data set of 230 organosilicon compounds are collected and divided into a training set of 184 compounds and a testing set of 46 compounds. The stepwise regression method is used to select the required molecular descriptors for predicting the FP of organosilicon compounds from 1538 molecular descriptors. Depending on the p-value for accepting a descriptor to enter the model, models with different number of descriptors are obtained. A 13-descriptor model and a 6-descriptor model are obtained with the p-value of 5 × 10−4 and 1 × 10−5, respectively. It is found that the 6-descriptor model could fit the training data with R2 = 0.8981 and predict the test data with Q2 = 0.8533 and the 13-descriptor model could fit the training data with R2 = 0.9293 and predict the test data with Q2 = 0.9245. The average predictive errors are less than 5% for both proposed models and they are useful for many practical applications, because the proposed models used only calculated descriptors from the molecular structure. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101381b Exemplaires
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Titre : Effects of O2 on characteristics of sulfur added to petroleum coke through reaction with SO2 Type de document : texte imprimé Auteurs : Eric A. Morris, Auteur ; Charles Q. Jia, Auteur Année de publication : 2011 Article en page(s) : pp. 12709–12717 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Sulfur petroleum coke Résumé : Alberta oil-sands petroleum coke is an abundant byproduct of the upgrading of bitumen. The current study aims to improve the current understanding of sulfur added to the surface of petroleum coke through reaction with sulfur dioxide (SO2) and how this is affected by a large excess of oxygen (O2). Particular focus is given to the distribution and speciation of sulfur within the coke particles, as well as its thermal stability. Petroleum coke was activated in SO2 with and without O2 in a packed bed reactor at 600−800 °C. The activated cokes were characterized with electron probe microanalysis (EPMA), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Cross-sectional analysis with EPMA of activated coke particles revealed that sulfur-rich coke particles (i.e., SIAC) could be produced with and without O2. Under low SO2 (3%), high O2 (18%) conditions, however, O2 competitively reacted with coke at 600 °C, and SO2 only reacted to form a sulfur-rich layer after O2 had been depleted. Analysis with XPS suggested that the sulfur-rich layer of the coke particles was made up of thiophene from the coke plus carbon−sulfur surface complexes, mainly heterocyclic sulfide and disulfide, while the presence of aliphatic sulfide, thiolactone, and thiol could not be ruled out. TGA and DSC analyses confirmed that sulfur added to activated coke via reaction with SO2 was not elemental in nature. In both N2 and air, sulfur added via high-temperature reaction with SO2 is more thermally stable than that of a commercial SIAC sulfurized at lower temperatures. This may have beneficial implications if these SO2 activated cokes were to be used to capture mercury, since they could be thermally regenerated with minimal loss of active sulfur surface sites while the captured mercury is collected, avoiding the costly and potentially problematic landfill disposal of Hg-containing activated carbon. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101388q
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12709–12717[article] Effects of O2 on characteristics of sulfur added to petroleum coke through reaction with SO2 [texte imprimé] / Eric A. Morris, Auteur ; Charles Q. Jia, Auteur . - 2011 . - pp. 12709–12717.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12709–12717
Mots-clés : Sulfur petroleum coke Résumé : Alberta oil-sands petroleum coke is an abundant byproduct of the upgrading of bitumen. The current study aims to improve the current understanding of sulfur added to the surface of petroleum coke through reaction with sulfur dioxide (SO2) and how this is affected by a large excess of oxygen (O2). Particular focus is given to the distribution and speciation of sulfur within the coke particles, as well as its thermal stability. Petroleum coke was activated in SO2 with and without O2 in a packed bed reactor at 600−800 °C. The activated cokes were characterized with electron probe microanalysis (EPMA), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Cross-sectional analysis with EPMA of activated coke particles revealed that sulfur-rich coke particles (i.e., SIAC) could be produced with and without O2. Under low SO2 (3%), high O2 (18%) conditions, however, O2 competitively reacted with coke at 600 °C, and SO2 only reacted to form a sulfur-rich layer after O2 had been depleted. Analysis with XPS suggested that the sulfur-rich layer of the coke particles was made up of thiophene from the coke plus carbon−sulfur surface complexes, mainly heterocyclic sulfide and disulfide, while the presence of aliphatic sulfide, thiolactone, and thiol could not be ruled out. TGA and DSC analyses confirmed that sulfur added to activated coke via reaction with SO2 was not elemental in nature. In both N2 and air, sulfur added via high-temperature reaction with SO2 is more thermally stable than that of a commercial SIAC sulfurized at lower temperatures. This may have beneficial implications if these SO2 activated cokes were to be used to capture mercury, since they could be thermally regenerated with minimal loss of active sulfur surface sites while the captured mercury is collected, avoiding the costly and potentially problematic landfill disposal of Hg-containing activated carbon. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101388q Exemplaires
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Titre : Phase equilibria of mixtures containing organic sulfur species (OSS) and water / hydrocarbons : VLE measurements and modeling using the cubic - plus - association equation of state Type de document : texte imprimé Auteurs : Javeed A. Awan, Auteur ; Ioannis Tsivintzelis, Auteur ; Martin P. Breil, Auteur Année de publication : 2011 Article en page(s) : pp. 12718–12725 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Organic sulfur Hydrocarbons Résumé : We report new vapor−liquid equilibrium (VLE) data for dimethyl sulfide (DMS) in pure water, performed at three temperatures (303, 330, and 362 K) in the 1−8 MPa pressure range. The total system pressure was maintained introducing CH4. The inlet mole fraction of DMS was the same in all experiments, around 1.5 × 10−3 in the liquid phase. A “static-analytic” method was used for performing all of the measurements. The objective is to provide experimental VLE data for the dimethyl sulfide + CH4 + water system, for which no data are available in the open literature. These data will allow industry to model sulfur emissions. The new VLE data as well as the VLE data of some binary systems from the literature containing organic sulfur species + hydrocarbon, organic sulfur species + water, and some ternary systems containing organic sulfur species in hydrocarbons and water have been modeled successfully with the cubic-plus-association (CPA) equation of state. Useful remarks are presented about the application of Henry’s constant values to estimate binary interaction parameters of the CPA EoS for the description of whole vapor−liquid equilibria. The results using CPA EoS show that the cross association interactions in the methyl mercaptan + water system and ethyl mercaptan + water system should be considered. In aqueous mixtures of higher mercaptans, the consideration of such interactions does not improve the calculations, indicating that they are rather weak. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101470b
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12718–12725[article] Phase equilibria of mixtures containing organic sulfur species (OSS) and water / hydrocarbons : VLE measurements and modeling using the cubic - plus - association equation of state [texte imprimé] / Javeed A. Awan, Auteur ; Ioannis Tsivintzelis, Auteur ; Martin P. Breil, Auteur . - 2011 . - pp. 12718–12725.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12718–12725
Mots-clés : Organic sulfur Hydrocarbons Résumé : We report new vapor−liquid equilibrium (VLE) data for dimethyl sulfide (DMS) in pure water, performed at three temperatures (303, 330, and 362 K) in the 1−8 MPa pressure range. The total system pressure was maintained introducing CH4. The inlet mole fraction of DMS was the same in all experiments, around 1.5 × 10−3 in the liquid phase. A “static-analytic” method was used for performing all of the measurements. The objective is to provide experimental VLE data for the dimethyl sulfide + CH4 + water system, for which no data are available in the open literature. These data will allow industry to model sulfur emissions. The new VLE data as well as the VLE data of some binary systems from the literature containing organic sulfur species + hydrocarbon, organic sulfur species + water, and some ternary systems containing organic sulfur species in hydrocarbons and water have been modeled successfully with the cubic-plus-association (CPA) equation of state. Useful remarks are presented about the application of Henry’s constant values to estimate binary interaction parameters of the CPA EoS for the description of whole vapor−liquid equilibria. The results using CPA EoS show that the cross association interactions in the methyl mercaptan + water system and ethyl mercaptan + water system should be considered. In aqueous mixtures of higher mercaptans, the consideration of such interactions does not improve the calculations, indicating that they are rather weak. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101470b Exemplaires
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Titre : Thermodynamic analysis of systems formed by alkyl esters with a - w alkyl dibromides : new experimental information and the use of a dense database to describe their behavior using the UNIFAC group contribution method and the COSMO - RS methodology Type de document : texte imprimé Auteurs : Ana Navas, Auteur ; Juan Ortega, Auteur ; Tomas Martin, Auteur Année de publication : 2011 Article en page(s) : pp. 12726–12739 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Thermodynamic Résumé : This is a theoretical study carried out on the experimental data obtained for 90 binary systems comprised of alkyl esters with dibromoalkanes, using data from previous publications and those corresponding to 20 mixtures presented here. The experimental part of this work corresponds to experimental measurements of HmE and VmE at T = 298.15 K and atmospheric pressure for systems containing propyl alkanoates (methanoate to butanoate) with 1,ω-dibromoalkanes (ω = 2−6). The systems containing propyl methanoate present HmE > 0, while the remaining ones give values of HmE that follow a sigmoid distribution. The VmE of these mixtures of propyl esters are either positive or negative, depending on the dihalide involved. Positive ones correspond to mixtures with short-chain dibromoalkanes, and contraction effects are observed with the increasing chain length of the dihalide compound. On the whole, experimental information suggests a specific behavior with either positive or negative structural mixing effects depending on the chain length of the compounds. HmE values were estimated theoretically by applying two different types of models. The UNIFAC group contribution model gives good results in the prediction, but only when the Br, Br/carboxylate interaction is considered to vary with the chains of the ester and dibromoalkane; mathematical expressions are presented to describe these variations for the entire set of mixtures. The COSMO-RS quantum-chemical method is also applied to predict HmE values for the systems studied and the results extrapolated to a set of 90 systems (alkyl alkanoates + dibromoalkane), optimizing the model parameters, especially to obtain an adequate description of the Van der Waals interactions. As a result, the optimized COSMO-RS method can be used to interpret the behavior of the HmE for the whole group of alkyl esters + dibromoalkane in terms of the different intermolecular interactions taking place inside the pure compounds and mixtures, especially in relation to the variable effects of the alkyl chains of the components on the mixing enthalpies. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101479v
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12726–12739[article] Thermodynamic analysis of systems formed by alkyl esters with a - w alkyl dibromides : new experimental information and the use of a dense database to describe their behavior using the UNIFAC group contribution method and the COSMO - RS methodology [texte imprimé] / Ana Navas, Auteur ; Juan Ortega, Auteur ; Tomas Martin, Auteur . - 2011 . - pp. 12726–12739.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12726–12739
Mots-clés : Thermodynamic Résumé : This is a theoretical study carried out on the experimental data obtained for 90 binary systems comprised of alkyl esters with dibromoalkanes, using data from previous publications and those corresponding to 20 mixtures presented here. The experimental part of this work corresponds to experimental measurements of HmE and VmE at T = 298.15 K and atmospheric pressure for systems containing propyl alkanoates (methanoate to butanoate) with 1,ω-dibromoalkanes (ω = 2−6). The systems containing propyl methanoate present HmE > 0, while the remaining ones give values of HmE that follow a sigmoid distribution. The VmE of these mixtures of propyl esters are either positive or negative, depending on the dihalide involved. Positive ones correspond to mixtures with short-chain dibromoalkanes, and contraction effects are observed with the increasing chain length of the dihalide compound. On the whole, experimental information suggests a specific behavior with either positive or negative structural mixing effects depending on the chain length of the compounds. HmE values were estimated theoretically by applying two different types of models. The UNIFAC group contribution model gives good results in the prediction, but only when the Br, Br/carboxylate interaction is considered to vary with the chains of the ester and dibromoalkane; mathematical expressions are presented to describe these variations for the entire set of mixtures. The COSMO-RS quantum-chemical method is also applied to predict HmE values for the systems studied and the results extrapolated to a set of 90 systems (alkyl alkanoates + dibromoalkane), optimizing the model parameters, especially to obtain an adequate description of the Van der Waals interactions. As a result, the optimized COSMO-RS method can be used to interpret the behavior of the HmE for the whole group of alkyl esters + dibromoalkane in terms of the different intermolecular interactions taking place inside the pure compounds and mixtures, especially in relation to the variable effects of the alkyl chains of the components on the mixing enthalpies. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101479v Exemplaires
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Titre : Influence of the Solvent Quality on the Thermodynamic Behavior of Polymethylphenylsiloxane Solutions Type de document : texte imprimé Auteurs : Cristina-Eliza Brunchi, Auteur ; Simona Morariu, Auteur ; Maria Cazacu, Auteur Année de publication : 2011 Article en page(s) : pp. 12740–12746 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Solvent quality Thermodynamic Résumé : In this work we investigate the effect of the solvent quality on the thermodynamic behavior of the polydimethyldiphenylsiloxane copolymer by using turbidimetry and viscosimetry. The turbidimetric method was used for the determination of the composition of the solvent mixture at the theta point. The experimental data obtained by using the capillary viscometry both in good and theta solvent conditions have been processed by using classical Huggins equation and new Wolf model (2007), which allows the calculation of intrinsic viscosities and other hydrodynamic parameters. The results obtained by using the two approaches were discussed comparatively. The conformational properties of copolymer in solution depend on their molecular structure, which is essentially dominated by the solvent quality, reflecting the balance of the interactions between the polymer chains and each solvent and that between solvent molecules. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1015238
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12740–12746[article] Influence of the Solvent Quality on the Thermodynamic Behavior of Polymethylphenylsiloxane Solutions [texte imprimé] / Cristina-Eliza Brunchi, Auteur ; Simona Morariu, Auteur ; Maria Cazacu, Auteur . - 2011 . - pp. 12740–12746.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12740–12746
Mots-clés : Solvent quality Thermodynamic Résumé : In this work we investigate the effect of the solvent quality on the thermodynamic behavior of the polydimethyldiphenylsiloxane copolymer by using turbidimetry and viscosimetry. The turbidimetric method was used for the determination of the composition of the solvent mixture at the theta point. The experimental data obtained by using the capillary viscometry both in good and theta solvent conditions have been processed by using classical Huggins equation and new Wolf model (2007), which allows the calculation of intrinsic viscosities and other hydrodynamic parameters. The results obtained by using the two approaches were discussed comparatively. The conformational properties of copolymer in solution depend on their molecular structure, which is essentially dominated by the solvent quality, reflecting the balance of the interactions between the polymer chains and each solvent and that between solvent molecules. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1015238 Exemplaires
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Titre : Beclomethasone microparticles for wet inhalation, produced by supercritical assisted atomization Type de document : texte imprimé Auteurs : Ernesto Reverchon, Auteur ; Renata Adami, Auteur ; Mariarosa Scognamiglio, Auteur Année de publication : 2011 Article en page(s) : pp. 12747-12755 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Supercritical state Microparticle Résumé : Supercritical assisted atomization (SAA) was used to produce micronized particles of beclomethasone dipropionate (BDP) to be used for inhalation therapy. Methanol, acetone, acetone + water 9% v/v, and methanol + water 4% v/v were tested as liquid solvents to explore their influence on particle size and crystalline structure of the precipitated powder. Particles with narrow size distributions (PSD) were obtained by changing the SAA process operating conditions. In particular, using acetone + water 9% v/v with a BDP concentration of 90 mg/mL, crystalline particles ranging between 0.2 and 4.7 μm were produced and 70% by volume of these particles ranged between 1 and 3 μm. PSD stability analysis in a wet formulation showed that BDP powder obtained by SAA does not modify over a long period of time. The results obtained on the laboratory scale plant were successfully reproduced on a pilot plant and a further refinement of the operating conditions was performed. About 30 g of BDP microparticles were produced per batch and a recovery of about 93 wt % of the micronized powder with respect to the injected quantity was obtained. The largest volumetric fraction of BDP particles falling in the range 1-3 μm was 83% on the pilot scale. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692032
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12747-12755[article] Beclomethasone microparticles for wet inhalation, produced by supercritical assisted atomization [texte imprimé] / Ernesto Reverchon, Auteur ; Renata Adami, Auteur ; Mariarosa Scognamiglio, Auteur . - 2011 . - pp. 12747-12755.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12747-12755
Mots-clés : Supercritical state Microparticle Résumé : Supercritical assisted atomization (SAA) was used to produce micronized particles of beclomethasone dipropionate (BDP) to be used for inhalation therapy. Methanol, acetone, acetone + water 9% v/v, and methanol + water 4% v/v were tested as liquid solvents to explore their influence on particle size and crystalline structure of the precipitated powder. Particles with narrow size distributions (PSD) were obtained by changing the SAA process operating conditions. In particular, using acetone + water 9% v/v with a BDP concentration of 90 mg/mL, crystalline particles ranging between 0.2 and 4.7 μm were produced and 70% by volume of these particles ranged between 1 and 3 μm. PSD stability analysis in a wet formulation showed that BDP powder obtained by SAA does not modify over a long period of time. The results obtained on the laboratory scale plant were successfully reproduced on a pilot plant and a further refinement of the operating conditions was performed. About 30 g of BDP microparticles were produced per batch and a recovery of about 93 wt % of the micronized powder with respect to the injected quantity was obtained. The largest volumetric fraction of BDP particles falling in the range 1-3 μm was 83% on the pilot scale. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692032 Exemplaires
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Titre : Characterization of oil - water emulsion and its use in enhanced oil recovery Type de document : texte imprimé Auteurs : Ajay Mandal, Auteur ; Abhijit Samanta, Auteur ; Achinta Bera, Auteur Année de publication : 2011 Article en page(s) : pp. 12756–12761 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Oil water emulsion Résumé : Oil-in-water emulsions are important in the petroleum industry as a displacing fluid for enhanced oil recovery (EOR). To investigate the efficiency of oil−water emulsions in EOR, experiments were performed to characterize the emulsions in terms of their physicochemical properties and size distribution of the dispersed oil droplet in water phase. In the present study commercially available gear oil was used to prepare oil-in-water emulsions. Flooding experiments were also carried out to evaluate the effectiveness of the emulsion as displacing fluid for enhanced oil recovery. Substantial additional recoveries (more than 20% of original oil in place) over conventional water flooding were obtained in the present investigation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101589x
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12756–12761[article] Characterization of oil - water emulsion and its use in enhanced oil recovery [texte imprimé] / Ajay Mandal, Auteur ; Abhijit Samanta, Auteur ; Achinta Bera, Auteur . - 2011 . - pp. 12756–12761.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12756–12761
Mots-clés : Oil water emulsion Résumé : Oil-in-water emulsions are important in the petroleum industry as a displacing fluid for enhanced oil recovery (EOR). To investigate the efficiency of oil−water emulsions in EOR, experiments were performed to characterize the emulsions in terms of their physicochemical properties and size distribution of the dispersed oil droplet in water phase. In the present study commercially available gear oil was used to prepare oil-in-water emulsions. Flooding experiments were also carried out to evaluate the effectiveness of the emulsion as displacing fluid for enhanced oil recovery. Substantial additional recoveries (more than 20% of original oil in place) over conventional water flooding were obtained in the present investigation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101589x Exemplaires
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Titre : Biogenic Synthesis of Au Nanoparticles Using Vascular Plants Type de document : texte imprimé Auteurs : Roza Bali, Auteur ; Andrew T. Harris, Auteur Année de publication : 2011 Article en page(s) : pp. 12762–12772 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nanoparticles Biogenic Résumé : The known metallophytes Brassica juncea (B. juncea) and Medicago sativa (M. sativa) were investigated for their ability to accumulate and sequester gold (Au) from aqueous solutions of KAuCl4. Once sequestered, some of the metal was stored as nanoparticles, throughout the epidermis, cortex, and vascular tissue for both species, but predominantly located in the xylem parenchyma cells. Nanoparticle size distribution within the plant tissues was determined. In general, particle sizes ranged between 2 nm to 2 μm in B. juncea and 2 nm to 1 μm in M. sativa and was location dependent; root located nanoparticles had similar size distributions in both species, whereas the distribution within above ground tissues differed between M. sativa and B. juncea, with B. juncea showing a much broader range of particle sizes. Au(0) nanoparticles were also formed ex vivo following contact between root exudates and an aqueous solution of KAuCl4 resulting in the reduction of Au(III) to Au(0). The largest proportion of particles was in the range 5−10 nm (B. juncea) and 10−20 nm (M. sativa). The mechanism of growth of Au(0) nanoparticles using live plants, both in vivo and ex vivo is consistent with Turkevich [Gold Bull. 1985, 18 (3), 86−91], who suggested that the process of Au(0) particle formation involved the interplay of crystal nucleation, growth, and coagulation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101600m
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12762–12772[article] Biogenic Synthesis of Au Nanoparticles Using Vascular Plants [texte imprimé] / Roza Bali, Auteur ; Andrew T. Harris, Auteur . - 2011 . - pp. 12762–12772.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12762–12772
Mots-clés : Nanoparticles Biogenic Résumé : The known metallophytes Brassica juncea (B. juncea) and Medicago sativa (M. sativa) were investigated for their ability to accumulate and sequester gold (Au) from aqueous solutions of KAuCl4. Once sequestered, some of the metal was stored as nanoparticles, throughout the epidermis, cortex, and vascular tissue for both species, but predominantly located in the xylem parenchyma cells. Nanoparticle size distribution within the plant tissues was determined. In general, particle sizes ranged between 2 nm to 2 μm in B. juncea and 2 nm to 1 μm in M. sativa and was location dependent; root located nanoparticles had similar size distributions in both species, whereas the distribution within above ground tissues differed between M. sativa and B. juncea, with B. juncea showing a much broader range of particle sizes. Au(0) nanoparticles were also formed ex vivo following contact between root exudates and an aqueous solution of KAuCl4 resulting in the reduction of Au(III) to Au(0). The largest proportion of particles was in the range 5−10 nm (B. juncea) and 10−20 nm (M. sativa). The mechanism of growth of Au(0) nanoparticles using live plants, both in vivo and ex vivo is consistent with Turkevich [Gold Bull. 1985, 18 (3), 86−91], who suggested that the process of Au(0) particle formation involved the interplay of crystal nucleation, growth, and coagulation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101600m Exemplaires
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Titre : Molecular characterization of gasoline and diesel streams Type de document : texte imprimé Auteurs : Yongwen Wu, Auteur ; Nan Zhang, Auteur Année de publication : 2011 Article en page(s) : pp. 12773-12782 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Gasoline Diesel Streams Résumé : A novel methodology to characterize gasoline and diesel streams into the molecular level is developed on the basis of molecular type homologous series (MTHS) matrix framework (Chem. Eng. Sci. 2005, 60, 6702−6717). The method comprises the enhancements of both representation matrix construction and transformation methodology of bulk properties into molecular composition. To improve the accuracy and adequacy of the representation model, different strategies are set up separately for gasoline and diesel streams for the consideration of isomers. By introducing statistical distribution and applying extensive bulk properties, the transformation approach is revolutionized to increase the usability, and tackle the challenge of possibly achieving significantly different molecular compositions from the same bulk properties of refining streams by existing transformation approaches. The proposed method is verified with both gasoline and diesel streams, and the results show a good agreement with measured data. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101647d
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12773-12782[article] Molecular characterization of gasoline and diesel streams [texte imprimé] / Yongwen Wu, Auteur ; Nan Zhang, Auteur . - 2011 . - pp. 12773-12782.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12773-12782
Mots-clés : Gasoline Diesel Streams Résumé : A novel methodology to characterize gasoline and diesel streams into the molecular level is developed on the basis of molecular type homologous series (MTHS) matrix framework (Chem. Eng. Sci. 2005, 60, 6702−6717). The method comprises the enhancements of both representation matrix construction and transformation methodology of bulk properties into molecular composition. To improve the accuracy and adequacy of the representation model, different strategies are set up separately for gasoline and diesel streams for the consideration of isomers. By introducing statistical distribution and applying extensive bulk properties, the transformation approach is revolutionized to increase the usability, and tackle the challenge of possibly achieving significantly different molecular compositions from the same bulk properties of refining streams by existing transformation approaches. The proposed method is verified with both gasoline and diesel streams, and the results show a good agreement with measured data. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101647d Exemplaires
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Titre : Numerical Investigation of Nucleating-Agent-Enhanced Heterogeneous Nucleation Type de document : texte imprimé Auteurs : C. Wang, Auteur ; S. N. Leung, Auteur ; M. Bussmann, Auteur Année de publication : 2011 Article en page(s) : pp. 12783–12792 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Heterogeneous nucleation Résumé : Nucleating agents have long been employed in polymeric foaming processes to promote cell nucleation, increase cell density, and improve cell uniformity. This improvement in foam morphology is usually considered to result from the enhanced heterogeneous nucleation caused by the lower free energy barrier for cell nucleation. However, less is known about the underlying mechanisms of nucleating-agent-enhanced nucleation. In the polymer foaming process, pressure is a critical parameter that affects the degree of supersaturation of gas within a polymer−gas solution. In most previous theoretical studies on cell nucleation, a uniform pressure was assumed throughout the solution. Although this assumption may be acceptable when no particles have been added, its validity is questionable when nucleating agents are present. It has been speculated that growing cells that have already been nucleated generate local flow fields that induce tensile stresses around nearby particles, resulting in local pressure fluctuations. The discontinuity at the interface between a nucleating agent particle and the surrounding polymer melt yields local pressure and stress fields around the particle that are different from those in the bulk, which may enhance it as a potential heterogeneous nucleation site. This paper presents a numerical analysis to investigate the pressure profile in the vicinity of nucleating agents and provides new information about the underlying mechanism that promotes cell nucleation in the presence of nucleating agents. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1017207
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12783–12792[article] Numerical Investigation of Nucleating-Agent-Enhanced Heterogeneous Nucleation [texte imprimé] / C. Wang, Auteur ; S. N. Leung, Auteur ; M. Bussmann, Auteur . - 2011 . - pp. 12783–12792.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12783–12792
Mots-clés : Heterogeneous nucleation Résumé : Nucleating agents have long been employed in polymeric foaming processes to promote cell nucleation, increase cell density, and improve cell uniformity. This improvement in foam morphology is usually considered to result from the enhanced heterogeneous nucleation caused by the lower free energy barrier for cell nucleation. However, less is known about the underlying mechanisms of nucleating-agent-enhanced nucleation. In the polymer foaming process, pressure is a critical parameter that affects the degree of supersaturation of gas within a polymer−gas solution. In most previous theoretical studies on cell nucleation, a uniform pressure was assumed throughout the solution. Although this assumption may be acceptable when no particles have been added, its validity is questionable when nucleating agents are present. It has been speculated that growing cells that have already been nucleated generate local flow fields that induce tensile stresses around nearby particles, resulting in local pressure fluctuations. The discontinuity at the interface between a nucleating agent particle and the surrounding polymer melt yields local pressure and stress fields around the particle that are different from those in the bulk, which may enhance it as a potential heterogeneous nucleation site. This paper presents a numerical analysis to investigate the pressure profile in the vicinity of nucleating agents and provides new information about the underlying mechanism that promotes cell nucleation in the presence of nucleating agents. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1017207 Exemplaires
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Titre : Evaluation of interaction forces between nanoparticles by molecular dynamics simulation Type de document : texte imprimé Auteurs : Qinghua Zeng, Auteur ; Aibing Yu, Auteur ; Gaoqing (Max) Lu, Auteur Année de publication : 2011 Article en page(s) : pp.12793 -12797 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Shape controlled synthesis Microscope Crystals Surface Résumé : Molecular dynamics simulations are used to quantify the interaction forces between nanoparticles, which are critical to nanoparticle systems. It is shown that the fluctuation of surface atomic density and the dynamics of collisions significantly affect the interaction forces. As a result, the Hamaker method cannot accurately estimate the interaction forces for nanoparticles. The proposed approach offers an effective method for determining the interaction forces between nanoparticles. © 2010 American Chemical Society. DEWEY : 660 ISSN : 0888-5885 En ligne : http://espace.library.uq.edu.au/view/UQ:226534
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp.12793 -12797[article] Evaluation of interaction forces between nanoparticles by molecular dynamics simulation [texte imprimé] / Qinghua Zeng, Auteur ; Aibing Yu, Auteur ; Gaoqing (Max) Lu, Auteur . - 2011 . - pp.12793 -12797.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp.12793 -12797
Mots-clés : Shape controlled synthesis Microscope Crystals Surface Résumé : Molecular dynamics simulations are used to quantify the interaction forces between nanoparticles, which are critical to nanoparticle systems. It is shown that the fluctuation of surface atomic density and the dynamics of collisions significantly affect the interaction forces. As a result, the Hamaker method cannot accurately estimate the interaction forces for nanoparticles. The proposed approach offers an effective method for determining the interaction forces between nanoparticles. © 2010 American Chemical Society. DEWEY : 660 ISSN : 0888-5885 En ligne : http://espace.library.uq.edu.au/view/UQ:226534 Exemplaires
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