Dépouillements

Dendrimers / Ernesto de Jesuse in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p.7968-7981 Titre : Dendrimers : solutions for catalyst separation and recycling Type de document : texte imprimé Auteurs : Ernesto de Jesuse, Auteur ; Juan c. Flores, Auteur Année de publication : 2008 Article en page(s) : p.7968-7981 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : DendrimersFunctionalized Résumé : Dendrimers provide new and practical solutions to the complex problem of catalyst separation from the product stream. Dendrimers functionalized with active metal complexes are themselves soluble, nanosized catalysts that are capable of combining the high activity and selectivity of classical homogeneous catalysts with the enhanced separation capabilities added by the macromolecule. This report reviews the recovery and recycling of metallodendrimer catalysts by different separation techniques, such as nanofiltration, precipitation, or catalyst immobilization on solid supports, or by the use of appropriate solvent media, as illustrated by representative examples. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800381d7968- [article] Dendrimers : solutions for catalyst separation and recycling [texte imprimé] / Ernesto de Jesuse, Auteur ; Juan c. Flores, Auteur . - 2008 . - p.7968-7981. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p.7968-7981 Mots-clés : DendrimersFunctionalized Résumé : Dendrimers provide new and practical solutions to the complex problem of catalyst separation from the product stream. Dendrimers functionalized with active metal complexes are themselves soluble, nanosized catalysts that are capable of combining the high activity and selectivity of classical homogeneous catalysts with the enhanced separation capabilities added by the macromolecule. This report reviews the recovery and recycling of metallodendrimer catalysts by different separation techniques, such as nanofiltration, precipitation, or catalyst immobilization on solid supports, or by the use of appropriate solvent media, as illustrated by representative examples. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800381d7968-

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Fuels from waste plastics by thermal and catalytic processes / J. Aguado in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 7982–7992 Titre : Fuels from waste plastics by thermal and catalytic processes : a review Type de document : texte imprimé Auteurs : J. Aguado, Auteur ; David P. Serrano, Auteur ; J. M. Escola, Auteur Année de publication : 2008 Article en page(s) : p. 7982–7992 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Plastic waste -- recycling fuels Catalytic processes Résumé : Feedstock recycling of plastic waste by thermal and catalytic processes is a promising route to eliminate this refuse (which is harmful to the environment) by obtaining, at the same time, products that are useful as fuels or chemicals. During the past decade, this option has undergone an important evolution from a promising scientific idea to an alternative that is very close to reality with commercial opportunities. Thus, several commercial processes have been developed worldwide, most of them especially addressed toward the preparation of diesel fuel. The present review highlights the most remarkable achievements of the field, providing a fundamental insight into this fascinating area and highlighting the main milestones that should be achieved in the next future for this alternative to become applied commercially on a large scale. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800393w [article] Fuels from waste plastics by thermal and catalytic processes : a review [texte imprimé] / J. Aguado, Auteur ; David P. Serrano, Auteur ; J. M. Escola, Auteur . - 2008 . - p. 7982–7992. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 7982–7992 Mots-clés : Plastic waste -- recycling fuels Catalytic processes Résumé : Feedstock recycling of plastic waste by thermal and catalytic processes is a promising route to eliminate this refuse (which is harmful to the environment) by obtaining, at the same time, products that are useful as fuels or chemicals. During the past decade, this option has undergone an important evolution from a promising scientific idea to an alternative that is very close to reality with commercial opportunities. Thus, several commercial processes have been developed worldwide, most of them especially addressed toward the preparation of diesel fuel. The present review highlights the most remarkable achievements of the field, providing a fundamental insight into this fascinating area and highlighting the main milestones that should be achieved in the next future for this alternative to become applied commercially on a large scale. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800393w

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Effective elimination ofpCBs catalyzed by thepalladium/hydrazine system as an ecological sustainableprocess / J. Gonzalo in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 7993–7996 Titre : Effective elimination ofpCBs catalyzed by thepalladium/hydrazine system as an ecological sustainableprocess Type de document : texte imprimé Auteurs : J. Gonzalo, Auteur ; Antonio Lafuente, Auteur Année de publication : 2008 Article en page(s) : p. 7993–7996 Langues : Anglais (eng) Résumé : Polychlorinated biphenyls (PCBs) undergo complete dechlorination catalyzed by palladium and hydrazine hydrochloride as hydrogen donor, in a bath at 60 °C or at room temperature in a reactor with an ultrasonic radiation source. The life of the catalyst system was evaluated in several reaction cycles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800110p [article] Effective elimination ofpCBs catalyzed by thepalladium/hydrazine system as an ecological sustainableprocess [texte imprimé] / J. Gonzalo, Auteur ; Antonio Lafuente, Auteur . - 2008 . - p. 7993–7996. Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 7993–7996 Résumé : Polychlorinated biphenyls (PCBs) undergo complete dechlorination catalyzed by palladium and hydrazine hydrochloride as hydrogen donor, in a bath at 60 °C or at room temperature in a reactor with an ultrasonic radiation source. The life of the catalyst system was evaluated in several reaction cycles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800110p

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Biodiesel from low-grade animal fat / Miguel Rodríguez in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 7997–8004 Titre : Biodiesel from low-grade animal fat : production process assessment and biodiesel properties characterization Type de document : texte imprimé Auteurs : Miguel Rodríguez, Auteur Année de publication : 2008 Article en page(s) : p. 7997–8004 Langues : Anglais (eng) Mots-clés : Biodiesel from different--industrial biodiesel production Résumé : Biodiesel from different mixtures of animal fat and soybean oil has been synthesized, and its properties have been evaluated and related to its composition. A mixture of 50 vol % of both raw materials has been selected as a suitable feedstock for industrial biodiesel production, and a computer simulation of the production process using Aspen Plus software has been carried out to evaluate the industrial feasibility of this scheme using this cheaper feedstock. The results obtained suggest that the process proposed and described produces a biodiesel with the selected feedstock acceptable by the standards with a lower final cost. The feedstocks employed are cheaper and consist of a waste fat without any other use, thus increasing the environmental benefits of the biodiesel and reducing dependency on conventional agricultural raw materials. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8002045 [article] Biodiesel from low-grade animal fat : production process assessment and biodiesel properties characterization [texte imprimé] / Miguel Rodríguez, Auteur . - 2008 . - p. 7997–8004. Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 7997–8004 Mots-clés : Biodiesel from different--industrial biodiesel production Résumé : Biodiesel from different mixtures of animal fat and soybean oil has been synthesized, and its properties have been evaluated and related to its composition. A mixture of 50 vol % of both raw materials has been selected as a suitable feedstock for industrial biodiesel production, and a computer simulation of the production process using Aspen Plus software has been carried out to evaluate the industrial feasibility of this scheme using this cheaper feedstock. The results obtained suggest that the process proposed and described produces a biodiesel with the selected feedstock acceptable by the standards with a lower final cost. The feedstocks employed are cheaper and consist of a waste fat without any other use, thus increasing the environmental benefits of the biodiesel and reducing dependency on conventional agricultural raw materials. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8002045

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Preparation characterization, and acidity evaluation of perfluorosulfonic acid-functionalized silica catalysts / Gema Blanco-Brieva in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8005-8010 Titre : Preparation characterization, and acidity evaluation of perfluorosulfonic acid-functionalized silica catalysts Type de document : texte imprimé Auteurs : Gema Blanco-Brieva, Auteur ; Jose M. Campos Martin, Auteur Année de publication : 2008 Article en page(s) : p. 8005-8010 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Solid acid catalysts perfluorsulfonic xps technique Résumé : Three different hybrid organic/inorganic solid acid catalysts were prepared by grafting perfluorosulfonic acid onto amorphous silica gel by covalently anchoring β-sultone onto the hydroxyl groups on the silica surface. The anchored sulfonic groups have been characterized by thermal analysis, infrared spectroscopy, and photoelectron spectroscopy (XPS). Particularly, the XPS technique has proven to be an extremely powerful tool to determine the nature and chemical state of sulfur and carbon, as well as the surface density of the acid groups. The hybrid organic/inorganic systems functionalized with sulfonic acid groups were tested in the esterification reaction of acetic acid with methanol in liquid phase. Activity results obtained at 333 K and using an initial molar ratio AcOOH:MeOH = 1:1 revealed that the acid-functionalized, nonsilylated catalyst reaches acetic acid conversion of ∼50%, which contrasts with the much lower level (∼30%) reached by a commercial Nafion silica composite sample. Treatment of the catalysts in methanol at 333 K under stirring for 48 h emphasized that only the acid-functionalized and silylated sample retains some of the sulfonic groups. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800221f [article] Preparation characterization, and acidity evaluation of perfluorosulfonic acid-functionalized silica catalysts [texte imprimé] / Gema Blanco-Brieva, Auteur ; Jose M. Campos Martin, Auteur . - 2008 . - p. 8005-8010. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8005-8010 Mots-clés : Solid acid catalysts perfluorsulfonic xps technique Résumé : Three different hybrid organic/inorganic solid acid catalysts were prepared by grafting perfluorosulfonic acid onto amorphous silica gel by covalently anchoring β-sultone onto the hydroxyl groups on the silica surface. The anchored sulfonic groups have been characterized by thermal analysis, infrared spectroscopy, and photoelectron spectroscopy (XPS). Particularly, the XPS technique has proven to be an extremely powerful tool to determine the nature and chemical state of sulfur and carbon, as well as the surface density of the acid groups. The hybrid organic/inorganic systems functionalized with sulfonic acid groups were tested in the esterification reaction of acetic acid with methanol in liquid phase. Activity results obtained at 333 K and using an initial molar ratio AcOOH:MeOH = 1:1 revealed that the acid-functionalized, nonsilylated catalyst reaches acetic acid conversion of ∼50%, which contrasts with the much lower level (∼30%) reached by a commercial Nafion silica composite sample. Treatment of the catalysts in methanol at 333 K under stirring for 48 h emphasized that only the acid-functionalized and silylated sample retains some of the sulfonic groups. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800221f

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New Two-Step Process for Propene Oxide Production (HPPO) Based on the Direct Synthesis of Hydrogen Peroxide / Gema Blanco-Brieva in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8011–8015 Titre : New Two-Step Process for Propene Oxide Production (HPPO) Based on the Direct Synthesis of Hydrogen Peroxide Type de document : texte imprimé Auteurs : Gema Blanco-Brieva, Auteur ; M.carmen capel sanchez, Auteur ; M.pilar de frutos, Auteur ; ana padilla polo, Auteur Année de publication : 2008 Article en page(s) : p. 8011–8015 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : oxide production -Aqueous solutions Résumé : In previous papers, we showed that (i) neutral solutions of hydrogen peroxide can be safely obtained by the direct reaction of H2 and O2 gas mixtures in the presence of Pd-loaded sulfonic acid resins and (ii) low molecular weight olefins can be successfully epoxidized using aqueous solutions of H2O2 in the presence of amorphous Ti/SiO2 catalysts. Against this background, this paper seeks to go one step further in our on-site H2O2 strategy by combining the direct synthesis of nonacidic H2O2 solutions with the catalyzed epoxidation of alkenes with hydrogen peroxide. In a first step, we optimized the reaction conditions for the direct synthesis of H2O2 working in a semibatch reactor. Aqueous solutions of 9 wt % H2O2 were then used in the epoxidation of oct-1-ene on a Ti-loaded amorphous silica catalyst, and reaction conditions were optimized. Finally, the propene epoxidation reaction was conducted in a continuous mode under the optimum reaction conditions selected (343 K, H2O2/catalyst ratio = 1:4, propene/catalyst ratio = 25, residence time 45 min). At steady-state, the conversion level of H2O2 reached 96% with a selectivity of hydrogen peroxide to propene oxide of 95%. After 135 h of reaction time, a slight decrease in the selectivity of H2O2 to epoxide was observed, with a decrease of H2O2 conversion from 96 to 80%. This catalyst deactivation is reversible, as original activity is fully recovered upon regeneration in air at 873 K. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800245r [article] New Two-Step Process for Propene Oxide Production (HPPO) Based on the Direct Synthesis of Hydrogen Peroxide [texte imprimé] / Gema Blanco-Brieva, Auteur ; M.carmen capel sanchez, Auteur ; M.pilar de frutos, Auteur ; ana padilla polo, Auteur . - 2008 . - p. 8011–8015. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8011–8015 Mots-clés : oxide production -Aqueous solutions Résumé : In previous papers, we showed that (i) neutral solutions of hydrogen peroxide can be safely obtained by the direct reaction of H2 and O2 gas mixtures in the presence of Pd-loaded sulfonic acid resins and (ii) low molecular weight olefins can be successfully epoxidized using aqueous solutions of H2O2 in the presence of amorphous Ti/SiO2 catalysts. Against this background, this paper seeks to go one step further in our on-site H2O2 strategy by combining the direct synthesis of nonacidic H2O2 solutions with the catalyzed epoxidation of alkenes with hydrogen peroxide. In a first step, we optimized the reaction conditions for the direct synthesis of H2O2 working in a semibatch reactor. Aqueous solutions of 9 wt % H2O2 were then used in the epoxidation of oct-1-ene on a Ti-loaded amorphous silica catalyst, and reaction conditions were optimized. Finally, the propene epoxidation reaction was conducted in a continuous mode under the optimum reaction conditions selected (343 K, H2O2/catalyst ratio = 1:4, propene/catalyst ratio = 25, residence time 45 min). At steady-state, the conversion level of H2O2 reached 96% with a selectivity of hydrogen peroxide to propene oxide of 95%. After 135 h of reaction time, a slight decrease in the selectivity of H2O2 to epoxide was observed, with a decrease of H2O2 conversion from 96 to 80%. This catalyst deactivation is reversible, as original activity is fully recovered upon regeneration in air at 873 K. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800245r

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Alkene Epoxidation with Ethylbenzene Hydroperoxides Using Molybdenum Heterogeneous Catalysts in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8016–8024 Titre : Alkene Epoxidation with Ethylbenzene Hydroperoxides Using Molybdenum Heterogeneous Catalysts Type de document : texte imprimé Année de publication : 2008 Article en page(s) : p. 8016–8024 Note générale : Chemical engineering Langues : Anglais (eng) Résumé : Molybdenum-containing catalysts were prepared by anchoring Mo(VI) groups onto different amino-functionalized silica surfaces and then tested in the epoxidation reaction of 1-octene with ethylbenzene hydroperoxide (EBHP) as an oxidant. Catalytic performance was found to depend on the chemical structure and nature of the functional group. EBHP conversion−time profiles exhibited an S-shaped behavior, suggesting that an induction period is required to develop the active site. Selectivity−conversion plots indicated that selectivities as high as 80% could be obtained at EBHP conversions of about 80% when the Mo complexes were immobilized on a silica substrate functionalized with a diamino-containing moiety. In contrast, surface functionalization with —COOH was found to be detrimental, as acid groups catalyze EBHP decomposition. Experiments designed to determine possible leaching of molybdenum into the reaction medium during the tests indicated that the catalyst prepared on a triamine-containing substrate exhibited good stability with almost no change in performance after three consecutive runs. The high stability of the Mo(VI) complex in this catalyst was shown by UV−vis and photoelectron spectroscopic techniques [article] Alkene Epoxidation with Ethylbenzene Hydroperoxides Using Molybdenum Heterogeneous Catalysts [texte imprimé] . - 2008 . - p. 8016–8024. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8016–8024 Résumé : Molybdenum-containing catalysts were prepared by anchoring Mo(VI) groups onto different amino-functionalized silica surfaces and then tested in the epoxidation reaction of 1-octene with ethylbenzene hydroperoxide (EBHP) as an oxidant. Catalytic performance was found to depend on the chemical structure and nature of the functional group. EBHP conversion−time profiles exhibited an S-shaped behavior, suggesting that an induction period is required to develop the active site. Selectivity−conversion plots indicated that selectivities as high as 80% could be obtained at EBHP conversions of about 80% when the Mo complexes were immobilized on a silica substrate functionalized with a diamino-containing moiety. In contrast, surface functionalization with —COOH was found to be detrimental, as acid groups catalyze EBHP decomposition. Experiments designed to determine possible leaching of molybdenum into the reaction medium during the tests indicated that the catalyst prepared on a triamine-containing substrate exhibited good stability with almost no change in performance after three consecutive runs. The high stability of the Mo(VI) complex in this catalyst was shown by UV−vis and photoelectron spectroscopic techniques

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Improved Procedure for Hydrogen Peroxide Production by Oxidation of Secondary Alcohols and Oxygenated Cosolvents† / pilsar de Fruto Escrig in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p.8025–8031 Titre : Improved Procedure for Hydrogen Peroxide Production by Oxidation of Secondary Alcohols and Oxygenated Cosolvents† Type de document : texte imprimé Auteurs : pilsar de Fruto Escrig, Auteur ; Alvaro garriga meco, Auteur ; ana padilla polo, Auteur Année de publication : 2008 Article en page(s) : p.8025–8031 Note générale : Chemical engineering Langues : Anglais (eng) Résumé : An improved procedure for the production of hydrogen peroxide via oxidation, with molecular oxygen, of secondary alcohols admixed with oxygenated co-solvents as primary alcohols and/or ether has been studied. The selectivity, conversion, and rates have been increased, in comparison to the data obtained in the absence of co-solvents. The increase observed in the oxidation rate of 1-phenylethanol in the presence of co-solvents has been interpreted using the chain co-oxidation reaction theory. The relative values of the termination constants of 1-phenylethanol and the tested co-solvents have been estimated. The lowest values of the termination constant of the peroxy radicals derived from the co-solvents explain the increase in the steady concentration of free radicals in the reaction media and, consequently, the enhancement observed in the co-oxidation rates. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800159u [article] Improved Procedure for Hydrogen Peroxide Production by Oxidation of Secondary Alcohols and Oxygenated Cosolvents† [texte imprimé] / pilsar de Fruto Escrig, Auteur ; Alvaro garriga meco, Auteur ; ana padilla polo, Auteur . - 2008 . - p.8025–8031. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p.8025–8031 Résumé : An improved procedure for the production of hydrogen peroxide via oxidation, with molecular oxygen, of secondary alcohols admixed with oxygenated co-solvents as primary alcohols and/or ether has been studied. The selectivity, conversion, and rates have been increased, in comparison to the data obtained in the absence of co-solvents. The increase observed in the oxidation rate of 1-phenylethanol in the presence of co-solvents has been interpreted using the chain co-oxidation reaction theory. The relative values of the termination constants of 1-phenylethanol and the tested co-solvents have been estimated. The lowest values of the termination constant of the peroxy radicals derived from the co-solvents explain the increase in the steady concentration of free radicals in the reaction media and, consequently, the enhancement observed in the co-oxidation rates. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800159u

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Strategies for the Immobilization of Homogeneous Catalysts and Their Use in the Synthesisof Carbamates / Aranzazu Orejón in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8025–8031 Titre : Strategies for the Immobilization of Homogeneous Catalysts and Their Use in the Synthesisof Carbamates Type de document : texte imprimé Auteurs : Aranzazu Orejón, Auteur ; Anna Masdeu-bulto, Auteur ; pilar salagre, Auteur Année de publication : 2008 Article en page(s) : p. 8025–8031 Note générale : Chemical engineering Langues : Anglais (eng) Résumé : Different methods of immobilization of N,N′-bis(salicylidene)ethylenediaminocobalt(II), [Co(salen)] complex, using K10 montmorillonite and silica have been used. These supported catalysts are active in the oxidative carbonylation of aniline using NaI as a promoter. The principal products obtained are N,N′-diphenylurea and 1-butyl-N-phenylcarbamate. En ligne : http://pubs.acs.org/toc/iecred/47/21 [article] Strategies for the Immobilization of Homogeneous Catalysts and Their Use in the Synthesisof Carbamates [texte imprimé] / Aranzazu Orejón, Auteur ; Anna Masdeu-bulto, Auteur ; pilar salagre, Auteur . - 2008 . - p. 8025–8031. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8025–8031 Résumé : Different methods of immobilization of N,N′-bis(salicylidene)ethylenediaminocobalt(II), [Co(salen)] complex, using K10 montmorillonite and silica have been used. These supported catalysts are active in the oxidative carbonylation of aniline using NaI as a promoter. The principal products obtained are N,N′-diphenylurea and 1-butyl-N-phenylcarbamate. En ligne : http://pubs.acs.org/toc/iecred/47/21

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Isoprene and C5 olefins production by oxidative dehydrogenation of isopentane / Rita X Valenzuela in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p.8037–8042 Titre : Isoprene and C5 olefins production by oxidative dehydrogenation of isopentane Type de document : texte imprimé Auteurs : Rita X Valenzuela, Auteur ; Josè M. Asperilla, Auteur ; Vicente Cortés, Auteur Année de publication : 2008 Article en page(s) : p.8037–8042 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : oxidative dehydrogenation soprene and isoamylenes Résumé : The current limited availability of isoprene and isoamylenes (methyl butenes), which are the feedstock for a variety of petrochemical processes, could be boosted by converting the isopentane contained in the same refinery C5-fractions from which they are obtained. The oxidative dehydrogenation (ODH) of isopentane to isoprene and isoamylenes for this purpose has been studied very little to date. We present here a study of this reaction on oxide catalysts, using oxygen as an oxidant, without any dopant in the feed. After a broad catalyst formulations screening, a V−Mg oxide catalyst (15 wt % V2O5) was selected to study the influence of the reaction parameters (temperature, residence time, and feed composition). Selectivity values of ca. 25% to isoprene, and 70% to isoprene plus isomylenes, could be attained under selected reaction conditions. These results are promising for the direct conversion of the branched C5-hydrocarbons fraction to isoprene. En ligne : http://pubs.acs.org/toc/iecred/47/21 [article] Isoprene and C5 olefins production by oxidative dehydrogenation of isopentane [texte imprimé] / Rita X Valenzuela, Auteur ; Josè M. Asperilla, Auteur ; Vicente Cortés, Auteur . - 2008 . - p.8037–8042. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p.8037–8042 Mots-clés : oxidative dehydrogenation soprene and isoamylenes Résumé : The current limited availability of isoprene and isoamylenes (methyl butenes), which are the feedstock for a variety of petrochemical processes, could be boosted by converting the isopentane contained in the same refinery C5-fractions from which they are obtained. The oxidative dehydrogenation (ODH) of isopentane to isoprene and isoamylenes for this purpose has been studied very little to date. We present here a study of this reaction on oxide catalysts, using oxygen as an oxidant, without any dopant in the feed. After a broad catalyst formulations screening, a V−Mg oxide catalyst (15 wt % V2O5) was selected to study the influence of the reaction parameters (temperature, residence time, and feed composition). Selectivity values of ca. 25% to isoprene, and 70% to isoprene plus isomylenes, could be attained under selected reaction conditions. These results are promising for the direct conversion of the branched C5-hydrocarbons fraction to isoprene. En ligne : http://pubs.acs.org/toc/iecred/47/21

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Organocatalysts for the reaction of dimethyl carbonate with 2,4-diaminotoluene / Raquel juàrez in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8043–8047 Titre : Organocatalysts for the reaction of dimethyl carbonate with 2,4-diaminotoluene Type de document : texte imprimé Auteurs : Raquel juàrez, Auteur ; Ana padilla, Auteur ; Avelino Corma, Auteur Année de publication : 2008 Article en page(s) : p. 8043–8047 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : dimethyl carbonate Résumé : The current limited availability of isoprene and isoamylenes (methyl butenes), which are the feedstock for a variety of petrochemical processes, could be boosted by converting the isopentane contained in the same refinery C5-fractions from which they are obtained. The oxidative dehydrogenation (ODH) of isopentane to isoprene and isoamylenes for this purpose has been studied very little to date. We present here a study of this reaction on oxide catalysts, using oxygen as an oxidant, without any dopant in the feed. After a broad catalyst formulations screening, a V−Mg oxide catalyst (15 wt % V2O5) was selected to study the influence of the reaction parameters (temperature, residence time, and feed composition). Selectivity values of ca. 25% to isoprene, and 70% to isoprene plus isomylenes, could be attained under selected reaction conditions. These results are promising for the direct conversion of the branched C5-hydrocarbons fraction to isoprene. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8003495 [article] Organocatalysts for the reaction of dimethyl carbonate with 2,4-diaminotoluene [texte imprimé] / Raquel juàrez, Auteur ; Ana padilla, Auteur ; Avelino Corma, Auteur . - 2008 . - p. 8043–8047. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8043–8047 Mots-clés : dimethyl carbonate Résumé : The current limited availability of isoprene and isoamylenes (methyl butenes), which are the feedstock for a variety of petrochemical processes, could be boosted by converting the isopentane contained in the same refinery C5-fractions from which they are obtained. The oxidative dehydrogenation (ODH) of isopentane to isoprene and isoamylenes for this purpose has been studied very little to date. We present here a study of this reaction on oxide catalysts, using oxygen as an oxidant, without any dopant in the feed. After a broad catalyst formulations screening, a V−Mg oxide catalyst (15 wt % V2O5) was selected to study the influence of the reaction parameters (temperature, residence time, and feed composition). Selectivity values of ca. 25% to isoprene, and 70% to isoprene plus isomylenes, could be attained under selected reaction conditions. These results are promising for the direct conversion of the branched C5-hydrocarbons fraction to isoprene. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8003495

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Reversible chemisorbents for carbon dioxide and their potential applications / ki bong lee Michael in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p 8048–8062 Titre : Reversible chemisorbents for carbon dioxide and their potential applications Type de document : texte imprimé Auteurs : ki bong lee Michael, Auteur ; G.Beaver Hugo, Auteur Année de publication : 2008 Article en page(s) : p 8048–8062 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : PhysisorbentsChemisorbents Résumé : Physisorbents like zeolites, activated carbons, silica, and alumina gels have been traditionally used for separation of bulk or trace carbon dioxide from a gas mixture using a pressure or a thermal swing adsorption process. These processes are generally operated at near ambient or at moderate temperatures (say En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800795y [article] Reversible chemisorbents for carbon dioxide and their potential applications [texte imprimé] / ki bong lee Michael, Auteur ; G.Beaver Hugo, Auteur . - 2008 . - p 8048–8062. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p 8048–8062 Mots-clés : PhysisorbentsChemisorbents Résumé : Physisorbents like zeolites, activated carbons, silica, and alumina gels have been traditionally used for separation of bulk or trace carbon dioxide from a gas mixture using a pressure or a thermal swing adsorption process. These processes are generally operated at near ambient or at moderate temperatures (say En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800795y

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Recent advances and applications of statistical associating fluid theory / Sugata p. Tan in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8063–8082 Titre : Recent advances and applications of statistical associating fluid theory Type de document : texte imprimé Auteurs : Sugata p. Tan, Auteur ; Hertanto Adidharma, Auteur ; Maciej Radosz, Auteur Année de publication : 2008 Article en page(s) : p. 8063–8082 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Statistical associating ThermodynamicIts performance Résumé : This review presents recent advances and applications of statistical associating fluid theory (SAFT), which has been extended in the past few years, conceptually and practically, to improve its performance and to represent thermodynamic properties of complex systems, such as associating polymers, polydispersed polymers, aqueous electrolytes, dipolar and quadrupolar systems, ionic liquids, near-critical systems, interfacial phenomena, crystallizable copolymers, gas hydrates, liquid crystals, biomaterials, and oil reservoir fluids, as well as dynamic properties such as viscosity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8008764 [article] Recent advances and applications of statistical associating fluid theory [texte imprimé] / Sugata p. Tan, Auteur ; Hertanto Adidharma, Auteur ; Maciej Radosz, Auteur . - 2008 . - p. 8063–8082. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8063–8082 Mots-clés : Statistical associating ThermodynamicIts performance Résumé : This review presents recent advances and applications of statistical associating fluid theory (SAFT), which has been extended in the past few years, conceptually and practically, to improve its performance and to represent thermodynamic properties of complex systems, such as associating polymers, polydispersed polymers, aqueous electrolytes, dipolar and quadrupolar systems, ionic liquids, near-critical systems, interfacial phenomena, crystallizable copolymers, gas hydrates, liquid crystals, biomaterials, and oil reservoir fluids, as well as dynamic properties such as viscosity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8008764

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Solubility of Antibiotics in Different Solvents. Part II. Non-Hydrochloride Forms of Tetracycline and Ciprofloxacin / Ana I. Caço in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p 8083–8089 Titre : Solubility of Antibiotics in Different Solvents. Part II. Non-Hydrochloride Forms of Tetracycline and Ciprofloxacin Type de document : texte imprimé Auteurs : Ana I. Caço, Auteur ; Fàtima Varanda, Auteur Année de publication : 2008 Article en page(s) : p 8083–8089 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Solubility of the hydrochloride Résumé : The aim of this work is to establish a comparison between the solubility of the hydrochloride and non-hydrochloride forms of ciprofloxacin and tetracycline in relevant solvents. For that purpose the solubilities of the non-hydrochloride forms of ciprofloxacin and tetracycline were measured in water, ethanol, 2-propanol, and acetone, in the temperature range between 293.15 and 323.15 K for ciprofloxacin and between 288.15 and 303.15 K for tetracycline. The obtained results were compared with those of part I of this study, published previously, where the solubilities of the respective hydrochloride forms of the antibiotics in the same solvents were investigated. The solubility of the hydrochloride forms in water is about 2 orders of magnitude higher than those of the respective base forms. In acetone, we see the opposite effect. For ethanol and 2-propanol the influence of the hydrochloride group of the antibiotic on the solubility in the alcohol is much smaller than for water and acetone. The experimental data was correlated with good results using two different activity coefficient models, NRTL and UNIQUAC, with UNIQUAC giving better results, particularly for ciprofloxacin. The performance of COSMO-RS model to describe the studied systems was also evaluated. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8003495 [article] Solubility of Antibiotics in Different Solvents. Part II. Non-Hydrochloride Forms of Tetracycline and Ciprofloxacin [texte imprimé] / Ana I. Caço, Auteur ; Fàtima Varanda, Auteur . - 2008 . - p 8083–8089. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p 8083–8089 Mots-clés : Solubility of the hydrochloride Résumé : The aim of this work is to establish a comparison between the solubility of the hydrochloride and non-hydrochloride forms of ciprofloxacin and tetracycline in relevant solvents. For that purpose the solubilities of the non-hydrochloride forms of ciprofloxacin and tetracycline were measured in water, ethanol, 2-propanol, and acetone, in the temperature range between 293.15 and 323.15 K for ciprofloxacin and between 288.15 and 303.15 K for tetracycline. The obtained results were compared with those of part I of this study, published previously, where the solubilities of the respective hydrochloride forms of the antibiotics in the same solvents were investigated. The solubility of the hydrochloride forms in water is about 2 orders of magnitude higher than those of the respective base forms. In acetone, we see the opposite effect. For ethanol and 2-propanol the influence of the hydrochloride group of the antibiotic on the solubility in the alcohol is much smaller than for water and acetone. The experimental data was correlated with good results using two different activity coefficient models, NRTL and UNIQUAC, with UNIQUAC giving better results, particularly for ciprofloxacin. The performance of COSMO-RS model to describe the studied systems was also evaluated. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8003495

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Synthesis of β-Bromo Glycerol Monoethers from α-Olefins / Sukhprit Singh in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8090–8094 Titre : Synthesis of β-Bromo Glycerol Monoethers from α-Olefins Type de document : texte imprimé Auteurs : Sukhprit Singh, Auteur ; Avinash Bhadani, Auteur ; Raman Kamboj, Auteur Année de publication : 2008 Article en page(s) : p. 8090–8094 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : OlefinsDodeceneHexadecene Résumé : α-Olefins (1-decene (1), 1-dodecene (2), 1-tetradecene (3), 1-hexadecene (4), and 1-octadecene (5)), when reacted with N-bromosuccinimide (NBS (6)) and solketal (7) at 60 °C, followed by deprotection with 10% HCl, are converted into chromatographically inseparable isomeric mixtures of β-bromo monoethers of glycerol: 3-(2-bromoalkyloxy)propane-1,2-diol (13a−17a)/3-(1-bromoalkane-2-yloxy)propane-1,2-diol (13b−17b). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800718b [article] Synthesis of β-Bromo Glycerol Monoethers from α-Olefins [texte imprimé] / Sukhprit Singh, Auteur ; Avinash Bhadani, Auteur ; Raman Kamboj, Auteur . - 2008 . - p. 8090–8094. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8090–8094 Mots-clés : OlefinsDodeceneHexadecene Résumé : α-Olefins (1-decene (1), 1-dodecene (2), 1-tetradecene (3), 1-hexadecene (4), and 1-octadecene (5)), when reacted with N-bromosuccinimide (NBS (6)) and solketal (7) at 60 °C, followed by deprotection with 10% HCl, are converted into chromatographically inseparable isomeric mixtures of β-bromo monoethers of glycerol: 3-(2-bromoalkyloxy)propane-1,2-diol (13a−17a)/3-(1-bromoalkane-2-yloxy)propane-1,2-diol (13b−17b). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800718b

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Alumina nanoparticles for the removal of Ni(II) from aqueous solutions / Y. C. sharma in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p 8095–8100 Titre : Alumina nanoparticles for the removal of Ni(II) from aqueous solutions Type de document : texte imprimé Auteurs : Y. C. sharma, Auteur ; V. Srivastava, Auteur ; Upadhyay, S., Auteur Année de publication : 2008 Article en page(s) : p 8095–8100 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Alumina Nanoparticles Résumé : Alumina nanoparticles were developed by the sol−gel method and were used for the removal of Ni(II) ions from aqueous solutions. The nanoparticles were characterized by TEM and XRD. Nanoparticles of alumina were then used for removal of Ni(II) ions from aqueous solutions of nickel. The nanosize of the adsorbent was confirmed by TEM and XRD. Removal (%) was found to be dependent on the initial concentration of nickel, and maximum removal was found to be 96.6% at 25 mg/L Ni(II). The removal increased from 99 to 99.6% by decreasing the initial concentration from 75 to 25 mg/L. Equilibrium time was found to be 120 min. As expected, higher removal was obtained at higher adsorbent dose. The removal was governed by first-order kinetics, and the value of the rate constant of adsorption was found to be 1.83 × 10−2 min−1 at 25 mg/L and 25 °C. The removal was found to be pH dependent, and maximum removal was found to be at pH 8.0. The adsorption process was endothermic in nature. The experimental data fit well the Langmuir and Freundlich isotherms. Constants of the two isotherm equations were determined. Thermodynamic studies for the present process were performed by determining the values of ΔG°, ΔH°, and ΔS° at different temperatures. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800831v [article] Alumina nanoparticles for the removal of Ni(II) from aqueous solutions [texte imprimé] / Y. C. sharma, Auteur ; V. Srivastava, Auteur ; Upadhyay, S., Auteur . - 2008 . - p 8095–8100. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p 8095–8100 Mots-clés : Alumina Nanoparticles Résumé : Alumina nanoparticles were developed by the sol−gel method and were used for the removal of Ni(II) ions from aqueous solutions. The nanoparticles were characterized by TEM and XRD. Nanoparticles of alumina were then used for removal of Ni(II) ions from aqueous solutions of nickel. The nanosize of the adsorbent was confirmed by TEM and XRD. Removal (%) was found to be dependent on the initial concentration of nickel, and maximum removal was found to be 96.6% at 25 mg/L Ni(II). The removal increased from 99 to 99.6% by decreasing the initial concentration from 75 to 25 mg/L. Equilibrium time was found to be 120 min. As expected, higher removal was obtained at higher adsorbent dose. The removal was governed by first-order kinetics, and the value of the rate constant of adsorption was found to be 1.83 × 10−2 min−1 at 25 mg/L and 25 °C. The removal was found to be pH dependent, and maximum removal was found to be at pH 8.0. The adsorption process was endothermic in nature. The experimental data fit well the Langmuir and Freundlich isotherms. Constants of the two isotherm equations were determined. Thermodynamic studies for the present process were performed by determining the values of ΔG°, ΔH°, and ΔS° at different temperatures. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800831v

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Evaluation of Mathematical algorithm for solving of fourier transform infrared spectroscopic and mass spectra / raimo A. ketola in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8101–8106 Titre : Evaluation of Mathematical algorithm for solving of fourier transform infrared spectroscopic and mass spectra Type de document : texte imprimé Auteurs : raimo A. ketola, Auteur ; virpi Tarkiainen, Auteur ; Jari kiuru, Auteur Année de publication : 2008 Article en page(s) : p. 8101–8106 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Solving of fourier Analytical methods Résumé : The aim of this study was to evaluate the benefits of the simultaneous use of two different analytical methods, namely Fourier transform infrared spectroscopy (FTIR) and mass spectrometry (MS), for online analysis of environmental and process samples. A mathematical method (NALMS) that identifies and quantifies all single components from a single multicomponent spectrum was previously developed for MS, and in this study, the same method, named as SPECTACS, was adopted for solving also an FTIR spectrum and a combined FTIR-MS spectrum. The performance of SPECTACS was evaluated by analyzing various gaseous samples, as case studies, containing volatile organic compounds, and the performance was compared with other methods, which are used to identify and quantitate organic compounds from multicomponent spectra. The results obtained show that SPECTACS with optimized noise reduction and solving a combined FTIR-MS spectrum can increase the reliability of identifying components in a single spectrum and also the accuracy in quantitative measurements when compared to the analysis with one analytical technique alone. The reasons for this improvement is evaluated and discussed in detail. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800851e [article] Evaluation of Mathematical algorithm for solving of fourier transform infrared spectroscopic and mass spectra [texte imprimé] / raimo A. ketola, Auteur ; virpi Tarkiainen, Auteur ; Jari kiuru, Auteur . - 2008 . - p. 8101–8106. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8101–8106 Mots-clés : Solving of fourier Analytical methods Résumé : The aim of this study was to evaluate the benefits of the simultaneous use of two different analytical methods, namely Fourier transform infrared spectroscopy (FTIR) and mass spectrometry (MS), for online analysis of environmental and process samples. A mathematical method (NALMS) that identifies and quantifies all single components from a single multicomponent spectrum was previously developed for MS, and in this study, the same method, named as SPECTACS, was adopted for solving also an FTIR spectrum and a combined FTIR-MS spectrum. The performance of SPECTACS was evaluated by analyzing various gaseous samples, as case studies, containing volatile organic compounds, and the performance was compared with other methods, which are used to identify and quantitate organic compounds from multicomponent spectra. The results obtained show that SPECTACS with optimized noise reduction and solving a combined FTIR-MS spectrum can increase the reliability of identifying components in a single spectrum and also the accuracy in quantitative measurements when compared to the analysis with one analytical technique alone. The reasons for this improvement is evaluated and discussed in detail. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800851e

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Particle Formation in Vinyl Chloride Emulsion Polymerization. Experimental Study / Hugo M. Vale in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8107–8118 Titre : Particle Formation in Vinyl Chloride Emulsion Polymerization. Experimental Study Type de document : texte imprimé Auteurs : Hugo M. Vale, Auteur ; Timothy F. L. McKenna, Auteur Année de publication : 2008 Article en page(s) : p. 8107–8118 Note générale : Chemical engineering Langues : Anglais (eng) Résumé : Particle formation in vinyl chloride emulsion polymerization has been investigated by means of ab initio and seeded experiments. A series of ab initio polymerizations was run in order to obtain reliable data regarding the dependence of the particle number on the emulsifier (SDS and SDBS) concentration, as well as to analyze the effect of the initiator concentration, stirring rate, and monomer-to-water ratio upon the particle number and the polymerization kinetics. Seeded polymerizations carried out at different concentrations of seed latex and surfactant made it possible to quantitatively evaluate the influence of these factors on the onset and extent of secondary particle formation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0715153 [article] Particle Formation in Vinyl Chloride Emulsion Polymerization. Experimental Study [texte imprimé] / Hugo M. Vale, Auteur ; Timothy F. L. McKenna, Auteur . - 2008 . - p. 8107–8118. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8107–8118 Résumé : Particle formation in vinyl chloride emulsion polymerization has been investigated by means of ab initio and seeded experiments. A series of ab initio polymerizations was run in order to obtain reliable data regarding the dependence of the particle number on the emulsifier (SDS and SDBS) concentration, as well as to analyze the effect of the initiator concentration, stirring rate, and monomer-to-water ratio upon the particle number and the polymerization kinetics. Seeded polymerizations carried out at different concentrations of seed latex and surfactant made it possible to quantitatively evaluate the influence of these factors on the onset and extent of secondary particle formation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0715153

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Kinetics and Mechanism of Decomposition of Hydrogen Peroxide over Pd/SiO2 Catalyst Yury Voloshin, James Manganaro and Adeniyi Lawal / Yury Voloshin in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8119–8125 Titre : Kinetics and Mechanism of Decomposition of Hydrogen Peroxide over Pd/SiO2 Catalyst Yury Voloshin, James Manganaro and Adeniyi Lawal Type de document : texte imprimé Auteurs : Yury Voloshin, Auteur ; James Manganaro, Auteur ; Adeniyi Lawal, Auteur Année de publication : 2008 Article en page(s) : p. 8119–8125 Note générale : Chemical engineering Langues : Anglais (eng) Résumé : Kinetics of hydrogen peroxide decomposition over Pd/SiO2 catalyst was investigated as part of a larger project to determine the overall kinetics of hydrogen peroxide formation by Pd/SiO2 catalyzed direct combination of hydrogen and oxygen. A Pd oxidative/reductive cycle mechanism for the decomposition of H2O2 over Pd/SiO2 was proposed. A Rideal−Eley rate expression based on this mechanism was shown to accurately correlate experimental data over a wide range of H2O2 concentration and temperature. This rate equation was shown to also apply in the presence of stabilizing concentrations of H2SO4. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8000452 [article] Kinetics and Mechanism of Decomposition of Hydrogen Peroxide over Pd/SiO2 Catalyst Yury Voloshin, James Manganaro and Adeniyi Lawal [texte imprimé] / Yury Voloshin, Auteur ; James Manganaro, Auteur ; Adeniyi Lawal, Auteur . - 2008 . - p. 8119–8125. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8119–8125 Résumé : Kinetics of hydrogen peroxide decomposition over Pd/SiO2 catalyst was investigated as part of a larger project to determine the overall kinetics of hydrogen peroxide formation by Pd/SiO2 catalyzed direct combination of hydrogen and oxygen. A Pd oxidative/reductive cycle mechanism for the decomposition of H2O2 over Pd/SiO2 was proposed. A Rideal−Eley rate expression based on this mechanism was shown to accurately correlate experimental data over a wide range of H2O2 concentration and temperature. This rate equation was shown to also apply in the presence of stabilizing concentrations of H2SO4. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8000452

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Effect of particle porosity on hysteresis in trickle-bed reactors / rabindranath Maiti in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8126–8135 Titre : Effect of particle porosity on hysteresis in trickle-bed reactors Type de document : texte imprimé Auteurs : rabindranath Maiti, Auteur ; Arnab Atta, Auteur ; K. D. P. Nigam, Auteur Année de publication : 2008 Article en page(s) : p. 8126–8135 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : HydrodynamicsParticle porosity Résumé : Hydrodynamics in trickle-bed reactors (TBRs) is quite complex because of the coexistence of gas−liquid−solid phases. Recent past hysteresis have been the subject of investigation to improve the understanding of the flow features at the microlevel, aiming to demystify the complex hydrodynamics. The purpose of the present study is to identify the role of particle porosity on hysteresis by choosing particles of different pore density (nonporous, semiporous, porous) but prepared from same material with identical shape and sizes. Experiments were carried out with industrial relevant-sized alumina extrudates in a 150 mm ID column using both a dry- and a wet-bed startup procedure. Comprehensive pressure drop hysteresis data were generated in increasing and decreasing modes of water flow in the presence of a constant flow of air at ambient condition. Pronounced but different magnitudes of pressure drop hysteresis were observed with all three types of particles at first cycle as well at subsequent cycle of operation. A deviation in pressure drop up to 90% was found between increasing and decreasing modes of operation, even after prewetting the bed. The same amount of hysteresis was observed for all the subsequent cycles, but the value is higher for particles with higher porosity. This confirms that particle porosity plays a major role in the existence of different flow texture at the microlevel in the trickle flow regime. This observation is reported here for the first time, and we believe that there is no such experimental data available in the literature. The genesis of this different hysteretic behavior of porous particles lies in the different ways liquid spreads/retracts over porous and nonporous particles. A conceptual framework of hysteresis proposed by Maiti et al. (2005), which is based on the concept of participating and nonparticipating particles and principles of liquid spreading on porous and nonporous substrates, is found to explain successfully the various features of hysteresis observed with all three types of particles. This study is expected to be useful to the TBR researcher and practitioner in enhancing the understanding further to demystify the complex hydrodynamic phenomena in TBRs. View: PDF | PDF w/ Links | Full Text HTML En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8003539 [article] Effect of particle porosity on hysteresis in trickle-bed reactors [texte imprimé] / rabindranath Maiti, Auteur ; Arnab Atta, Auteur ; K. D. P. Nigam, Auteur . - 2008 . - p. 8126–8135. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8126–8135 Mots-clés : HydrodynamicsParticle porosity Résumé : Hydrodynamics in trickle-bed reactors (TBRs) is quite complex because of the coexistence of gas−liquid−solid phases. Recent past hysteresis have been the subject of investigation to improve the understanding of the flow features at the microlevel, aiming to demystify the complex hydrodynamics. The purpose of the present study is to identify the role of particle porosity on hysteresis by choosing particles of different pore density (nonporous, semiporous, porous) but prepared from same material with identical shape and sizes. Experiments were carried out with industrial relevant-sized alumina extrudates in a 150 mm ID column using both a dry- and a wet-bed startup procedure. Comprehensive pressure drop hysteresis data were generated in increasing and decreasing modes of water flow in the presence of a constant flow of air at ambient condition. Pronounced but different magnitudes of pressure drop hysteresis were observed with all three types of particles at first cycle as well at subsequent cycle of operation. A deviation in pressure drop up to 90% was found between increasing and decreasing modes of operation, even after prewetting the bed. The same amount of hysteresis was observed for all the subsequent cycles, but the value is higher for particles with higher porosity. This confirms that particle porosity plays a major role in the existence of different flow texture at the microlevel in the trickle flow regime. This observation is reported here for the first time, and we believe that there is no such experimental data available in the literature. The genesis of this different hysteretic behavior of porous particles lies in the different ways liquid spreads/retracts over porous and nonporous particles. A conceptual framework of hysteresis proposed by Maiti et al. (2005), which is based on the concept of participating and nonparticipating particles and principles of liquid spreading on porous and nonporous substrates, is found to explain successfully the various features of hysteresis observed with all three types of particles. This study is expected to be useful to the TBR researcher and practitioner in enhancing the understanding further to demystify the complex hydrodynamic phenomena in TBRs. View: PDF | PDF w/ Links | Full Text HTML En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8003539

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Mercury oxidation over the V2O5(WO3)/tiO2 commercial scr catalyst / Hiroyuki Kamata in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p 8136–8141 Titre : Mercury oxidation over the V2O5(WO3)/tiO2 commercial scr catalyst Type de document : texte imprimé Auteurs : Hiroyuki Kamata, Auteur ; Shun-ichiro Ueno, Auteur ; Toshiyuki Naito, Auteur Année de publication : 2008 Article en page(s) : p 8136–8141 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Mercury oxidationHydrochloric acid Résumé : Mercury oxidation by hydrochloric acid over the V2O5(WO3)/TiO2 commercial SCR catalyst was investigated. Both fresh and aged catalysts with honeycomb structure, which were exposed to a coal combustion flue gas in a coal-fired boiler for over 71 000 h, were examined. The aged catalysts were characterized by X-ray and SEM-EDX analysis to examine the presence of ash deposition on the surface. The mercury oxidation rate was enhanced by increasing HCl concentrations and inhibited strongly by the presence of NH3. This behavior could be explained by a kinetic model assuming that HCl competes for the catalyst active sites against NH3. As the catalyst operation time increased, the mercury oxidation rate was observed to decrease considerably in the presence of NH3 while NO reduction rate was apparently nearly unchanged. By examining aged catalysts, deposits stemming from fly ash and SO2/SO3 were observed to accumulate continuously on the catalyst surface. The ash deposited on the surface may partially block the active catalyst sites and decrease their number. The decrease of the number of active sites on the catalyst surface caused NH3 to remain unreacted in the honeycomb catalyst. The decrease of the Hg0 oxidation rate was caused by the inhibition effect of NH3 remaining in the catalyst. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800363g [article] Mercury oxidation over the V2O5(WO3)/tiO2 commercial scr catalyst [texte imprimé] / Hiroyuki Kamata, Auteur ; Shun-ichiro Ueno, Auteur ; Toshiyuki Naito, Auteur . - 2008 . - p 8136–8141. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p 8136–8141 Mots-clés : Mercury oxidationHydrochloric acid Résumé : Mercury oxidation by hydrochloric acid over the V2O5(WO3)/TiO2 commercial SCR catalyst was investigated. Both fresh and aged catalysts with honeycomb structure, which were exposed to a coal combustion flue gas in a coal-fired boiler for over 71 000 h, were examined. The aged catalysts were characterized by X-ray and SEM-EDX analysis to examine the presence of ash deposition on the surface. The mercury oxidation rate was enhanced by increasing HCl concentrations and inhibited strongly by the presence of NH3. This behavior could be explained by a kinetic model assuming that HCl competes for the catalyst active sites against NH3. As the catalyst operation time increased, the mercury oxidation rate was observed to decrease considerably in the presence of NH3 while NO reduction rate was apparently nearly unchanged. By examining aged catalysts, deposits stemming from fly ash and SO2/SO3 were observed to accumulate continuously on the catalyst surface. The ash deposited on the surface may partially block the active catalyst sites and decrease their number. The decrease of the number of active sites on the catalyst surface caused NH3 to remain unreacted in the honeycomb catalyst. The decrease of the Hg0 oxidation rate was caused by the inhibition effect of NH3 remaining in the catalyst. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800363g

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Influence of Binder on the CatalyticperformaInfluence of binder on the catalytic nce of ptSnNa/ZSM-5 catalyst for propane dehydrogenation / Hui Liu in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8142–8147 Titre : Influence of Binder on the CatalyticperformaInfluence of binder on the catalytic nce of ptSnNa/ZSM-5 catalyst for propane dehydrogenation Type de document : texte imprimé Auteurs : Hui Liu, Auteur ; Yuming Zhou, Auteur ; Yiwei Zhang, Auteur Année de publication : 2008 Article en page(s) : p. 8142–8147 Note générale : Chemical engineering Langues : Anglais (eng) Résumé : The influence of different binders (alumina, silica sol, and montmorillonite) on the structure and performance of PtSnNa/ZSM-5 catalysts for propane dehydrogenation to propene was studied. Temperature-programmed desoption of ammonia (NH3-TPD), hydrogen chemisorption, BET surface area measurement, solid-state 27Al MAS NMR spectroscopy, catalyst particle mechanical strength, and X-ray diffraction (XRD) were used to characterize the catalysts. After agglomeration with different binders, the mechanical strength of all catalyst particles increased obviously in comparison with the nonagglomerated sample and the Al species amounts of the catalysts were affected greatly by the binder. A slightly acidic change was observed for the catalysts with different binders, but the metal dispersion on the carrier of different samples was clearly different. The result of propane dehydrogenation indicated that the catalyst based on PtSnNa/ZSM-5 agglomerated with alumina showed the highest conversion and high selectivity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800693t [article] Influence of Binder on the CatalyticperformaInfluence of binder on the catalytic nce of ptSnNa/ZSM-5 catalyst for propane dehydrogenation [texte imprimé] / Hui Liu, Auteur ; Yuming Zhou, Auteur ; Yiwei Zhang, Auteur . - 2008 . - p. 8142–8147. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8142–8147 Résumé : The influence of different binders (alumina, silica sol, and montmorillonite) on the structure and performance of PtSnNa/ZSM-5 catalysts for propane dehydrogenation to propene was studied. Temperature-programmed desoption of ammonia (NH3-TPD), hydrogen chemisorption, BET surface area measurement, solid-state 27Al MAS NMR spectroscopy, catalyst particle mechanical strength, and X-ray diffraction (XRD) were used to characterize the catalysts. After agglomeration with different binders, the mechanical strength of all catalyst particles increased obviously in comparison with the nonagglomerated sample and the Al species amounts of the catalysts were affected greatly by the binder. A slightly acidic change was observed for the catalysts with different binders, but the metal dispersion on the carrier of different samples was clearly different. The result of propane dehydrogenation indicated that the catalyst based on PtSnNa/ZSM-5 agglomerated with alumina showed the highest conversion and high selectivity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800693t

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Effect of Temperature on Reduction of CaSO4 Oxygen Carrier in Chemical-Looping Combustion of Simulated Coal Gas in a Fluidized Bed Reactor / Oilei Song in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8148–8159 Titre : Effect of Temperature on Reduction of CaSO4 Oxygen Carrier in Chemical-Looping Combustion of Simulated Coal Gas in a Fluidized Bed Reactor Type de document : texte imprimé Auteurs : Oilei Song, Auteur ; Rui Xiao, Auteur ; Zhongyi Deng, Auteur Année de publication : 2008 Article en page(s) : p. 8148–8159 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Chemical-looping combustion Résumé : Chemical-looping combustion (CLC) is a promising combustion technology for gaseous and solid fuel with efficient use of energy and inherent separation of CO2. The concept of a coal-fueled CLC system using calcium sulfate (CaSO4) as oxygen carrier is proposed in this study. Reduction tests of CaSO4 oxygen carrier with simulated coal gas were performed in a laboratory-scale fluidized bed reactor in the temperature range of 890−950 °C. A high concentration of CO2 was obtained at the initial reduction period. CaSO4 oxygen carrier exhibited high reactivity initially and decreased gradually at the late period of reduction. The sulfur release during the reduction of CaSO4 as oxygen carrier was also observed and analyzed. H2 and CO conversions were greatly influenced by reduction temperature. The carbon deposition ratio was found to be quite low. The oxygen carrier conversion and mass-based reaction rates during the reduction at typical temperatures were compared. Higher temperatures would enhance reaction rates and result in high conversion of oxygen carrier. An XRD patterns study indicated that CaS was the dominant product of reduction and the variation of relative intensity with temperature is in agreement with the solid conversion. The slight content of CaO in reduced oxygen carrier at high temperatures was due to the formation of SO2 and H2S during the reduction period. ESEM analysis indicated that the surface structure of oxygen carrier particles changed significantly from impervious to porous after reduction. Slight agglomeration of small grains occurred for reduced particles at 950 °C. EDS analysis also demonstrated the transfer of oxygen from the oxygen carrier to the fuel gas and a certain amount of sulfur loss and CaO formation on the surface at higher temperatures. The reduction kinetics of CaSO4 oxygen carrier was explored with the shrinking unreacted-core model. The apparent kinetic parameters were obtained, and the kinetic equation well predicted the experimental data. Finally, some basic considerations on the use of CaSO4 oxygen carrier in a CLC system for solid fuels were discussed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8007264 [article] Effect of Temperature on Reduction of CaSO4 Oxygen Carrier in Chemical-Looping Combustion of Simulated Coal Gas in a Fluidized Bed Reactor [texte imprimé] / Oilei Song, Auteur ; Rui Xiao, Auteur ; Zhongyi Deng, Auteur . - 2008 . - p. 8148–8159. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8148–8159 Mots-clés : Chemical-looping combustion Résumé : Chemical-looping combustion (CLC) is a promising combustion technology for gaseous and solid fuel with efficient use of energy and inherent separation of CO2. The concept of a coal-fueled CLC system using calcium sulfate (CaSO4) as oxygen carrier is proposed in this study. Reduction tests of CaSO4 oxygen carrier with simulated coal gas were performed in a laboratory-scale fluidized bed reactor in the temperature range of 890−950 °C. A high concentration of CO2 was obtained at the initial reduction period. CaSO4 oxygen carrier exhibited high reactivity initially and decreased gradually at the late period of reduction. The sulfur release during the reduction of CaSO4 as oxygen carrier was also observed and analyzed. H2 and CO conversions were greatly influenced by reduction temperature. The carbon deposition ratio was found to be quite low. The oxygen carrier conversion and mass-based reaction rates during the reduction at typical temperatures were compared. Higher temperatures would enhance reaction rates and result in high conversion of oxygen carrier. An XRD patterns study indicated that CaS was the dominant product of reduction and the variation of relative intensity with temperature is in agreement with the solid conversion. The slight content of CaO in reduced oxygen carrier at high temperatures was due to the formation of SO2 and H2S during the reduction period. ESEM analysis indicated that the surface structure of oxygen carrier particles changed significantly from impervious to porous after reduction. Slight agglomeration of small grains occurred for reduced particles at 950 °C. EDS analysis also demonstrated the transfer of oxygen from the oxygen carrier to the fuel gas and a certain amount of sulfur loss and CaO formation on the surface at higher temperatures. The reduction kinetics of CaSO4 oxygen carrier was explored with the shrinking unreacted-core model. The apparent kinetic parameters were obtained, and the kinetic equation well predicted the experimental data. Finally, some basic considerations on the use of CaSO4 oxygen carrier in a CLC system for solid fuels were discussed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8007264

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Investigation of Double-Stage Preferential CO Oxidation Reactor over Bimetallic Au−Pt Supported on A-Zeolite Catalyst / Apanee Luengnaruemitchai in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8160–8165 Titre : Investigation of Double-Stage Preferential CO Oxidation Reactor over Bimetallic Au−Pt Supported on A-Zeolite Catalyst Type de document : texte imprimé Auteurs : Apanee Luengnaruemitchai, Auteur ; pattarasuda Naknam, Auteur ; sujitra wogkasemjit, Auteur Année de publication : 2008 Article en page(s) : p. 8160–8165 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : CO oxidation Résumé : This article presents experiment data on the preferential CO oxidation (PROX) in a hydrogen-rich stream, currently the most practical method for CO removal induced by a double-stage process. The reaction was carried out in a microreactor testing unit using Au and Pt supported on an A zeolite catalyst in the temperature range of 50−300 °C under atmospheric pressure. The reactant gas mixture contained CO (1%), O2 (1%), H2 (40%), CO2 (0−10%), and H2O (0−10%), with the balance being He, at a total flow rate of 50 mL/min. The results clearly show that the addition of the second stage significantly reduces the H2 loss and the O2 requirements while greatly increasing the CO selectivity from ∼48 to ∼58%. The addition of CO2 and H2O in the feed slightly reduces the CO oxidation activity both in single- and double-stage processes. Moreover, the double-stage process shows a CO removal efficiency of over 99% during 60 h of testing at a reaction temperature of 170 °C in the simulated reformed gas (CO2- and H2O-free [article] Investigation of Double-Stage Preferential CO Oxidation Reactor over Bimetallic Au−Pt Supported on A-Zeolite Catalyst [texte imprimé] / Apanee Luengnaruemitchai, Auteur ; pattarasuda Naknam, Auteur ; sujitra wogkasemjit, Auteur . - 2008 . - p. 8160–8165. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8160–8165 Mots-clés : CO oxidation Résumé : This article presents experiment data on the preferential CO oxidation (PROX) in a hydrogen-rich stream, currently the most practical method for CO removal induced by a double-stage process. The reaction was carried out in a microreactor testing unit using Au and Pt supported on an A zeolite catalyst in the temperature range of 50−300 °C under atmospheric pressure. The reactant gas mixture contained CO (1%), O2 (1%), H2 (40%), CO2 (0−10%), and H2O (0−10%), with the balance being He, at a total flow rate of 50 mL/min. The results clearly show that the addition of the second stage significantly reduces the H2 loss and the O2 requirements while greatly increasing the CO selectivity from ∼48 to ∼58%. The addition of CO2 and H2O in the feed slightly reduces the CO oxidation activity both in single- and double-stage processes. Moreover, the double-stage process shows a CO removal efficiency of over 99% during 60 h of testing at a reaction temperature of 170 °C in the simulated reformed gas (CO2- and H2O-free

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Role of the Activated Carbon Surface on Catalytic Wet Peroxide Oxidation / Ana Rey in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8166–8174 Titre : Role of the Activated Carbon Surface on Catalytic Wet Peroxide Oxidation Type de document : texte imprimé Auteurs : Ana Rey, Auteur ; Marisol Faraldos, Auteur ; Ana Bahamonde, Auteur Année de publication : 2008 Article en page(s) : p. 8166–8174 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Activated carbonsCatalytst characterization Résumé : Three activated carbons with fairly different characteristics have been checked in catalytic wet peroxide oxidation (CWPO) using phenol as a model compound for the purpose of learning the role of these materials which can be used as supports for the preparation of Fe or other metallic catalysts. A complex contribution of mixed effects is involved making difficult to predict the behavior of a given activated carbon. The surface of these materials promotes the undesirable decomposition of H2O2 to unreactive O2 instead of •OH radicals in an extent depending on the nature and accessibility of the oxygen groups. A frankly basic surface including groups such as pyrone with an egg-shell type distribution on the carbon particle seems to be beneficial for a more effective decomposition of H2O2 leading to a higher oxidation activity. The presence of iron in the activated carbon ashes is also an important factor which may hide in part other effects derived from the structure and surface composition of the carbon. However, that factor cannot explain by itself the differences found in the behavior of the activated carbons since two of them with a similar Fe content showed markedly different activities in CWPO of phenol. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800538t [article] Role of the Activated Carbon Surface on Catalytic Wet Peroxide Oxidation [texte imprimé] / Ana Rey, Auteur ; Marisol Faraldos, Auteur ; Ana Bahamonde, Auteur . - 2008 . - p. 8166–8174. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8166–8174 Mots-clés : Activated carbonsCatalytst characterization Résumé : Three activated carbons with fairly different characteristics have been checked in catalytic wet peroxide oxidation (CWPO) using phenol as a model compound for the purpose of learning the role of these materials which can be used as supports for the preparation of Fe or other metallic catalysts. A complex contribution of mixed effects is involved making difficult to predict the behavior of a given activated carbon. The surface of these materials promotes the undesirable decomposition of H2O2 to unreactive O2 instead of •OH radicals in an extent depending on the nature and accessibility of the oxygen groups. A frankly basic surface including groups such as pyrone with an egg-shell type distribution on the carbon particle seems to be beneficial for a more effective decomposition of H2O2 leading to a higher oxidation activity. The presence of iron in the activated carbon ashes is also an important factor which may hide in part other effects derived from the structure and surface composition of the carbon. However, that factor cannot explain by itself the differences found in the behavior of the activated carbons since two of them with a similar Fe content showed markedly different activities in CWPO of phenol. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800538t

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Strontium-Doped Lanthanum Cobaltite and Manganite: Highly Active Catalysts for Toluene Complete Oxidation / Deng Jiguang in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8175–8183 Titre : Strontium-Doped Lanthanum Cobaltite and Manganite: Highly Active Catalysts for Toluene Complete Oxidation Type de document : texte imprimé Auteurs : Deng Jiguang, Auteur ; Lei Zhang, Auteur ; Hongxing Dai, Auteur Année de publication : 2008 Article en page(s) : p. 8175–8183 Note générale : Chemical engineering Langues : Anglais (eng) Résumé : La1−xSrxMO3−δ (M = Co, Mn; x = 0, 0.4) catalysts have been fabricated via a strategy of citric acid complexing and hydrothermal treatment. The oxidation of toluene was used as a probe reaction for the evaluation of catalytic performance. The materials were characterized by a number of techniques. We observed that the catalytic activity (evaluated by the temperature required for 80% conversion of toluene, T80%) increased in the sequence of LaMnO3.10 (T80% = 295 °C) En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800585x [article] Strontium-Doped Lanthanum Cobaltite and Manganite: Highly Active Catalysts for Toluene Complete Oxidation [texte imprimé] / Deng Jiguang, Auteur ; Lei Zhang, Auteur ; Hongxing Dai, Auteur . - 2008 . - p. 8175–8183. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8175–8183 Résumé : La1−xSrxMO3−δ (M = Co, Mn; x = 0, 0.4) catalysts have been fabricated via a strategy of citric acid complexing and hydrothermal treatment. The oxidation of toluene was used as a probe reaction for the evaluation of catalytic performance. The materials were characterized by a number of techniques. We observed that the catalytic activity (evaluated by the temperature required for 80% conversion of toluene, T80%) increased in the sequence of LaMnO3.10 (T80% = 295 °C) En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800585x

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Direct Chlorination of Nickel-Containing Materials. Recovery of the Metal from Different Sources / J. F. Álvarez in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8184–8191 Titre : Direct Chlorination of Nickel-Containing Materials. Recovery of the Metal from Different Sources Type de document : texte imprimé Auteurs : J. F. Álvarez, Auteur ; Ana E. Bohé, Auteur Année de publication : 2008 Article en page(s) : p. 8184–8191 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Chlorination of nickel Résumé : In the present work, the chlorination of nickel-containing materials is proposed: using NiO and mixtures that simulate the conditions of 12 wt % NiO−Al2O3 catalyst, prepared by mechanical mixing and incipient wetness impregnation (IWI), the reaction with gaseous chlorine proceeds from 500 to 800 °C. Non-isothermal experiments from 20 to 950 °C and isothermal measurements at 725, 800, and 850 °C were performed under Ar−Cl2 atmosphere in a thermogravimetric (TG) system. Direct chlorination of the mixtures was carried out isothermally in a tubular reactor under a flow of Cl2 from 500 to 800 °C. The chlorination started at 725, 473, and 428 °C for NiO, the mechanical mixture, and the IWI mixture, respectively. The high temperature for NiO can be explained by its BET area, which is small enough to reduce the reactivity of the sample. The recovery factor of Ni from Al2O3 attained at 800 °C was 85% for the mechanical mixture and 96% for the IWI mixture. All the species were characterized by X-ray diffraction (XRD), scanning-electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) techniques. They were quantified by X-ray fluorescence spectrometry (XRF), and BET surface area (BET) was measured in the samples. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8006598 [article] Direct Chlorination of Nickel-Containing Materials. Recovery of the Metal from Different Sources [texte imprimé] / J. F. Álvarez, Auteur ; Ana E. Bohé, Auteur . - 2008 . - p. 8184–8191. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8184–8191 Mots-clés : Chlorination of nickel Résumé : In the present work, the chlorination of nickel-containing materials is proposed: using NiO and mixtures that simulate the conditions of 12 wt % NiO−Al2O3 catalyst, prepared by mechanical mixing and incipient wetness impregnation (IWI), the reaction with gaseous chlorine proceeds from 500 to 800 °C. Non-isothermal experiments from 20 to 950 °C and isothermal measurements at 725, 800, and 850 °C were performed under Ar−Cl2 atmosphere in a thermogravimetric (TG) system. Direct chlorination of the mixtures was carried out isothermally in a tubular reactor under a flow of Cl2 from 500 to 800 °C. The chlorination started at 725, 473, and 428 °C for NiO, the mechanical mixture, and the IWI mixture, respectively. The high temperature for NiO can be explained by its BET area, which is small enough to reduce the reactivity of the sample. The recovery factor of Ni from Al2O3 attained at 800 °C was 85% for the mechanical mixture and 96% for the IWI mixture. All the species were characterized by X-ray diffraction (XRD), scanning-electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) techniques. They were quantified by X-ray fluorescence spectrometry (XRF), and BET surface area (BET) was measured in the samples. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8006598

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Modeling of Catalyst Activity Profiles in Fixed-Bed Reactors with a Moment Transformation Method / Jonas Roininen in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p 8192–8196 Titre : Modeling of Catalyst Activity Profiles in Fixed-Bed Reactors with a Moment Transformation Method Type de document : texte imprimé Auteurs : Jonas Roininen, Auteur ; Ville Alopaeus, Auteur Année de publication : 2008 Article en page(s) : p 8192–8196 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : catalyst activity profiles Résumé : A model for pseudo-steady-state catalyst activity profiles in a fixed-bed reactor is presented. It is based on conservation of moments of the exact catalyst activity profile, as calculated from the catalyst deactivation rate. These moments are then transformed analytically into a polynomial approximation of the activity profile for each time step. Then temporal and spatial evolution of the catalyst activity can be followed, and correspondingly accurate predictions of reactor performance with partly deactivated catalyst can be carried out. The present model is especially suitable for situations where the observed reaction rate is not solely determined by kinetics of a catalytic reaction, but also by heat or mass transfer limitations, or if the pressure drop in the reactor affects reaction rates. A further important class is when multiple reactions are taking place with different mechanisms so that the dominant mechanism changes as catalyst is deactivated. It can also be used in catalyst lifespan design, since measured temperature gradients can be followed by the model and transformed into information regarding catalyst activity profile. Also optimization of reactor operation with partly deactivated catalyst can be improved. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8007665 [article] Modeling of Catalyst Activity Profiles in Fixed-Bed Reactors with a Moment Transformation Method [texte imprimé] / Jonas Roininen, Auteur ; Ville Alopaeus, Auteur . - 2008 . - p 8192–8196. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p 8192–8196 Mots-clés : catalyst activity profiles Résumé : A model for pseudo-steady-state catalyst activity profiles in a fixed-bed reactor is presented. It is based on conservation of moments of the exact catalyst activity profile, as calculated from the catalyst deactivation rate. These moments are then transformed analytically into a polynomial approximation of the activity profile for each time step. Then temporal and spatial evolution of the catalyst activity can be followed, and correspondingly accurate predictions of reactor performance with partly deactivated catalyst can be carried out. The present model is especially suitable for situations where the observed reaction rate is not solely determined by kinetics of a catalytic reaction, but also by heat or mass transfer limitations, or if the pressure drop in the reactor affects reaction rates. A further important class is when multiple reactions are taking place with different mechanisms so that the dominant mechanism changes as catalyst is deactivated. It can also be used in catalyst lifespan design, since measured temperature gradients can be followed by the model and transformed into information regarding catalyst activity profile. Also optimization of reactor operation with partly deactivated catalyst can be improved. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8007665

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Isomerization of n-Pentane Catalyzed by Acidic Chloroaluminate Ionic liquids / Rui Zhang in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8205–8210 Titre : Isomerization of n-Pentane Catalyzed by Acidic Chloroaluminate Ionic liquids Type de document : texte imprimé Auteurs : Rui Zhang, Auteur ; Xianghai Meng, Auteur ; Zhichang Liu, Auteur Année de publication : 2008 Article en page(s) : p. 8205–8210 Note générale : Chemical engineerimg Determination of lonic liquid Langues : Anglais (eng) Mots-clés : acidity characterization Résumé : Isomerization oil becomes an important motor gasoline blending component due to increased statutory reduction of aromatics and olefins (high octane number components) contents in motor gasoline. The ionic liquid Et3NHCl−AlCl3 (mole fraction of AlCl3 is 0.67) shows good catalytic performance for the isomerization of n-pentane. The conversion of n-pentane increases with the enhancement of reaction temperature, reaction time, and catalyst/oil volume ratio (C/O ratio), while the yield of isomerization oil and the selectivity of isoparaffins decrease. The optimal reaction temperature, reaction time, and C/O ratio are 30 °C, 3 h, and 1:1, respectively. Under the optimal reaction conditions, the conversion of n-pentane, the yield of isomerization oil, and the selectivity of isoparaffins are 44.61 wt %, 96.07 wt %, and 90.52%, respectively. High conversion of n-pentane favors the octane number improvement of isomerization oil without the circulation of n-pentane, while low conversion of n-pentane is preferential with the circulation of n-pentane. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801013j [article] Isomerization of n-Pentane Catalyzed by Acidic Chloroaluminate Ionic liquids [texte imprimé] / Rui Zhang, Auteur ; Xianghai Meng, Auteur ; Zhichang Liu, Auteur . - 2008 . - p. 8205–8210. Chemical engineerimg Determination of lonic liquid Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8205–8210 Mots-clés : acidity characterization Résumé : Isomerization oil becomes an important motor gasoline blending component due to increased statutory reduction of aromatics and olefins (high octane number components) contents in motor gasoline. The ionic liquid Et3NHCl−AlCl3 (mole fraction of AlCl3 is 0.67) shows good catalytic performance for the isomerization of n-pentane. The conversion of n-pentane increases with the enhancement of reaction temperature, reaction time, and catalyst/oil volume ratio (C/O ratio), while the yield of isomerization oil and the selectivity of isoparaffins decrease. The optimal reaction temperature, reaction time, and C/O ratio are 30 °C, 3 h, and 1:1, respectively. Under the optimal reaction conditions, the conversion of n-pentane, the yield of isomerization oil, and the selectivity of isoparaffins are 44.61 wt %, 96.07 wt %, and 90.52%, respectively. High conversion of n-pentane favors the octane number improvement of isomerization oil without the circulation of n-pentane, while low conversion of n-pentane is preferential with the circulation of n-pentane. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801013j

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Study and characterization of Al-MCM-41 prepared with the assistance of supercritical CO2 / Li Shimin in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p 8211–8217 Titre : Study and characterization of Al-MCM-41 prepared with the assistance of supercritical CO2 Type de document : texte imprimé Auteurs : Li Shimin, Auteur ; Qun Xu, Auteur ; Chen, Alain, Auteur Année de publication : 2008 Article en page(s) : p 8211–8217 Note générale : Chemical engineering Langues : Anglais (eng) Résumé : Supercritical carbon dioxide (SC CO2) was used as a carrier/solvent for the “dry” alumination of mesoporous silica to prepare aluminum-containing mesoporous MCM-41. The effect of alumination on the structure and crystallinity of the materials was studied. In addition, the hydrothermal and thermal stability of this material have been investigated and compared with Al-MCM-41 prepared via conventional impregnation and direct hydrothermal synthesis. Irrespective of the preparation method, the surface area, pore diameter, pore volume, and crystallinity of Al-MCM-41 all decrease after hydrothermal and thermal treatments. However, Al-MCM-41 materials prepared with the assistance of SC CO2 possess better hydrothermal and thermal stability. This method allows for the incorporation of aluminum onto rather than into pores wall, without disintegration of the mesoporous structure, compared to Al-MCM-41 that has been prepared via impregnation and direct hydrothermal synthesis. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800046h [article] Study and characterization of Al-MCM-41 prepared with the assistance of supercritical CO2 [texte imprimé] / Li Shimin, Auteur ; Qun Xu, Auteur ; Chen, Alain, Auteur . - 2008 . - p 8211–8217. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p 8211–8217 Résumé : Supercritical carbon dioxide (SC CO2) was used as a carrier/solvent for the “dry” alumination of mesoporous silica to prepare aluminum-containing mesoporous MCM-41. The effect of alumination on the structure and crystallinity of the materials was studied. In addition, the hydrothermal and thermal stability of this material have been investigated and compared with Al-MCM-41 prepared via conventional impregnation and direct hydrothermal synthesis. Irrespective of the preparation method, the surface area, pore diameter, pore volume, and crystallinity of Al-MCM-41 all decrease after hydrothermal and thermal treatments. However, Al-MCM-41 materials prepared with the assistance of SC CO2 possess better hydrothermal and thermal stability. This method allows for the incorporation of aluminum onto rather than into pores wall, without disintegration of the mesoporous structure, compared to Al-MCM-41 that has been prepared via impregnation and direct hydrothermal synthesis. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800046h

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Characterization and rheological properties of kaolinite−silicon Oil pastes / Dogan, Mehmet in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8218–8227 Titre : Characterization and rheological properties of kaolinite−silicon Oil pastes Type de document : texte imprimé Auteurs : Dogan, Mehmet, Auteur ; Zürriye Yilmaz, Auteur ; Alkan, Mahir, Auteur Année de publication : 2008 Article en page(s) : p. 8218–8227 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : oil pastes Résumé : A description of experiments carried out to determine the effect of some parameters on the extrusion behavior of particulate pastes is given. The effects of particle size, solid/liquid ratio, temperature, shear rate, and die dimensiones on rheological behavior of kaolinite−silicon oil pastes were investigated. These pastes were prepared by mixing kaolinite powder with chosen amounts of silicon oil. Capillary rheometry was used to determine the extrusion properties of the pastes. All pastes were found to exhibit non-Newtonian, pseudoplastic behavior under all experimental conditions. The viscosity decreased with an increase in temperature and particle size and with a decrease in solid/liquid ratio. The whole paste was properly described by the Herschel−Bulkley model and exhibited a shear thinning behavior. The yield stress increased with an increase in particle size and kaolinite amount and a decrease in temperature, reflecting the increase in paste viscosity. The flow behavior index, n, varied in the range of 0.077−0.534. The Arrhenius model gave a good description of the temperature effect on the shear viscosity of paste, and the Ea value appeared in the range of 7.4−32.6 kJ/mol. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800727d [article] Characterization and rheological properties of kaolinite−silicon Oil pastes [texte imprimé] / Dogan, Mehmet, Auteur ; Zürriye Yilmaz, Auteur ; Alkan, Mahir, Auteur . - 2008 . - p. 8218–8227. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8218–8227 Mots-clés : oil pastes Résumé : A description of experiments carried out to determine the effect of some parameters on the extrusion behavior of particulate pastes is given. The effects of particle size, solid/liquid ratio, temperature, shear rate, and die dimensiones on rheological behavior of kaolinite−silicon oil pastes were investigated. These pastes were prepared by mixing kaolinite powder with chosen amounts of silicon oil. Capillary rheometry was used to determine the extrusion properties of the pastes. All pastes were found to exhibit non-Newtonian, pseudoplastic behavior under all experimental conditions. The viscosity decreased with an increase in temperature and particle size and with a decrease in solid/liquid ratio. The whole paste was properly described by the Herschel−Bulkley model and exhibited a shear thinning behavior. The yield stress increased with an increase in particle size and kaolinite amount and a decrease in temperature, reflecting the increase in paste viscosity. The flow behavior index, n, varied in the range of 0.077−0.534. The Arrhenius model gave a good description of the temperature effect on the shear viscosity of paste, and the Ea value appeared in the range of 7.4−32.6 kJ/mol. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800727d

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Coating of TiO2 Thin Films on the Surface of SiO2 Microspheres: Toward Industrial Photocatalysis / Gang Li in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p 8228–8232 Titre : Coating of TiO2 Thin Films on the Surface of SiO2 Microspheres: Toward Industrial Photocatalysis Type de document : texte imprimé Auteurs : Gang Li, Auteur ; Renbi Bai, Auteur ; X. S. Zhao, Auteur Année de publication : 2008 Article en page(s) : p 8228–8232 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Surface of SiO2 Treating wastewater. Résumé : A core/shell SiO2/TiO2 photocatalyst was prepared using a liquid-phase deposition (LPD) method. Zeta-potential measurement showed that deposition of a layer of polyelectrolyte on the surface of SiO2 microspheres was a prerequisite for subsequent deposition of the TiO2 shell with a controllable and uniform thickness. The photocatalytic activity of the core/shell SiO2/TiO2 catalyst for decomposition of Orange II in liquid phase was observed to be comparable with that of P25 (a commercial TiO2 product of Degussa). Experimental data also showed that the SiO2/TiO2 core/shell nanostructured photocatalyst can be easily separated from the reaction medium by sedimentation, and the solid can be recycled and reused. Thus, the photocatalyst described in this work represents a new catalyst system with a high potential for practical applications in treating wastewater. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800561y [article] Coating of TiO2 Thin Films on the Surface of SiO2 Microspheres: Toward Industrial Photocatalysis [texte imprimé] / Gang Li, Auteur ; Renbi Bai, Auteur ; X. S. Zhao, Auteur . - 2008 . - p 8228–8232. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p 8228–8232 Mots-clés : Surface of SiO2 Treating wastewater. Résumé : A core/shell SiO2/TiO2 photocatalyst was prepared using a liquid-phase deposition (LPD) method. Zeta-potential measurement showed that deposition of a layer of polyelectrolyte on the surface of SiO2 microspheres was a prerequisite for subsequent deposition of the TiO2 shell with a controllable and uniform thickness. The photocatalytic activity of the core/shell SiO2/TiO2 catalyst for decomposition of Orange II in liquid phase was observed to be comparable with that of P25 (a commercial TiO2 product of Degussa). Experimental data also showed that the SiO2/TiO2 core/shell nanostructured photocatalyst can be easily separated from the reaction medium by sedimentation, and the solid can be recycled and reused. Thus, the photocatalyst described in this work represents a new catalyst system with a high potential for practical applications in treating wastewater. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800561y

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Novel Biodegradable Poly(1,4-dioxan-2-one) Grafted Soy Protein Copolymer: Synthesis and Characterization / Yi-Dong Li in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8233–8238 Titre : Novel Biodegradable Poly(1,4-dioxan-2-one) Grafted Soy Protein Copolymer: Synthesis and Characterization Type de document : texte imprimé Auteurs : Yi-Dong Li, Auteur ; Si - Chong Chen, Auteur ; Jian-Bing Zeng, Auteur ; Yu-Zhong Wang, Auteur Année de publication : 2008 Article en page(s) : p. 8233–8238 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : BiodegradableNuclear magnetic resonance (NMR) Résumé : A novel biodegradable copolymer, poly(1,4-dioxan-2-one) (PPDO) grafted soy protein isolate (SPI) (SPI-g-PPDO), was investigated. The ring-opening graft copolymerization of SPI-g-PPDO was carried out with stannous octoate as a co-initiator/catalyst in the presence of azeotropic solvent at 80 °C. The molecular structure of SPI-g-PPDO was characterized by Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR). The results suggested that the content and length of PPDO graft chains of the copolymer increased with the increase of monomer (1,4-dioxan-2-one, PDO) content. Moreover, the results of differential scanning calorimetry (DSC) showed that the copolymer has a definite glass transition temperature and melting point, meaning that the copolymer can be melt-processed. In addition, the copolymers could form crystals after the grafting polymerization. The crystallization ability increases with the increase of graft chain length. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800994s [article] Novel Biodegradable Poly(1,4-dioxan-2-one) Grafted Soy Protein Copolymer: Synthesis and Characterization [texte imprimé] / Yi-Dong Li, Auteur ; Si - Chong Chen, Auteur ; Jian-Bing Zeng, Auteur ; Yu-Zhong Wang, Auteur . - 2008 . - p. 8233–8238. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8233–8238 Mots-clés : BiodegradableNuclear magnetic resonance (NMR) Résumé : A novel biodegradable copolymer, poly(1,4-dioxan-2-one) (PPDO) grafted soy protein isolate (SPI) (SPI-g-PPDO), was investigated. The ring-opening graft copolymerization of SPI-g-PPDO was carried out with stannous octoate as a co-initiator/catalyst in the presence of azeotropic solvent at 80 °C. The molecular structure of SPI-g-PPDO was characterized by Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR). The results suggested that the content and length of PPDO graft chains of the copolymer increased with the increase of monomer (1,4-dioxan-2-one, PDO) content. Moreover, the results of differential scanning calorimetry (DSC) showed that the copolymer has a definite glass transition temperature and melting point, meaning that the copolymer can be melt-processed. In addition, the copolymers could form crystals after the grafting polymerization. The crystallization ability increases with the increase of graft chain length. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800994s

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An Exponentially Weighted Moving Average Method for Identification and Monitoring of / Shyh-Hong Hwang in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8239–8249 Titre : An Exponentially Weighted Moving Average Method for Identification and Monitoring of Type de document : texte imprimé Auteurs : Shyh-Hong Hwang, Auteur ; Ho-Tsen Chen, Auteur ; Chuei-Tin Chang, Auteur Année de publication : 2008 Article en page(s) : p. 8239–8249 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : The stochasticEWMA parameter estimators Résumé : To identify parametric models for stochastic systems, the standard least-squares method tends to yield biased parameter estimates owing to correlated residuals resulting from unknown stochastic disturbances. Although the consistency properties of parameter estimates could generically be secured by instrumental variable methods, the inadequate choices of instruments and prefilters would render them much less efficient. This article establishes a method to identify an ARARX (AutoRegressive AutoRegressive with eXogenous input), an ARMAX (AutoRegressive Moving Average with eXogenous input), or a BJ (Box–Jenkins) model based on the process output data smoothed by the EWMA (Exponentially Weighted Moving Average). The major advantages of the method are 2-fold. First, the proposed off-line and online algorithms often acquire unbiased, efficient, and consistent parameter estimation from identification tests operating in open loop or closed loop. Second, the resultant process plus disturbance model can be easily employed to remove the autocorrelation in process data for accurate statistical process monitoring. Monte-Carlo simulation studies demonstrate that the proposed method provides reliable parametric models for a wide variety of noise characteristics and is highly robust with respect to the sampling period, sample size, and noise-to-signal ratio. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0707218 [article] An Exponentially Weighted Moving Average Method for Identification and Monitoring of [texte imprimé] / Shyh-Hong Hwang, Auteur ; Ho-Tsen Chen, Auteur ; Chuei-Tin Chang, Auteur . - 2008 . - p. 8239–8249. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8239–8249 Mots-clés : The stochasticEWMA parameter estimators Résumé : To identify parametric models for stochastic systems, the standard least-squares method tends to yield biased parameter estimates owing to correlated residuals resulting from unknown stochastic disturbances. Although the consistency properties of parameter estimates could generically be secured by instrumental variable methods, the inadequate choices of instruments and prefilters would render them much less efficient. This article establishes a method to identify an ARARX (AutoRegressive AutoRegressive with eXogenous input), an ARMAX (AutoRegressive Moving Average with eXogenous input), or a BJ (Box–Jenkins) model based on the process output data smoothed by the EWMA (Exponentially Weighted Moving Average). The major advantages of the method are 2-fold. First, the proposed off-line and online algorithms often acquire unbiased, efficient, and consistent parameter estimation from identification tests operating in open loop or closed loop. Second, the resultant process plus disturbance model can be easily employed to remove the autocorrelation in process data for accurate statistical process monitoring. Monte-Carlo simulation studies demonstrate that the proposed method provides reliable parametric models for a wide variety of noise characteristics and is highly robust with respect to the sampling period, sample size, and noise-to-signal ratio. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0707218

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Fault detection and classification for a process with multiple production grades / Jialin Liu in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8250–8262 Titre : Fault detection and classification for a process with multiple production grades Type de document : texte imprimé Auteurs : Jialin Liu, Auteur Année de publication : 2008 Article en page(s) : p. 8250–8262 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Industrial polyethylene Résumé : In practice, an industrial polyethylene process produces various products, even often developing new production grades for market demand. Therefore, the process has not only multiple operating conditions, but also time-varying characteristics. In addition, the process measurements inevitably are redundant and noisy. It is a challenging problem for on-line classifying the operating conditions in the industrial process. In this paper, principal component analysis (PCA) is applied to the reference data set to reduce the dimensions of variables and eliminate the collinearities among process measurements. Since outliers are inevitable in a real plant data set, they significantly stretch the cluster centers and covariances and reach an unreliable solution. In this paper, the distance-based fuzzy c-means (DFCM) algorithm is proposed. A boundary distance for each cluster is derived for identifying outliers, which should be discarded from the reference data set. Before the on-line classification, the statistic Q and T2 of new data have to be evaluated. If any one of the statistics is out of its control limits, it indicates the new data do not belong to the PCA subspace and they should be collected for the next model update. In this paper, the blockwise recursive formulas for updating the means and covariance matrix are derived. By utilizing the updated means and covariance, a new PCA subspace that accounts for all events is derived recursively. In addition, through rotating and shifting the coordinates of the PCA subspace, the cluster parameters on the new subspace can be directly transferred from the previous one. The proposed method was successfully applied to monitor a polyethylene process with multiple production grades and time-varying characteristics. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0710014 [article] Fault detection and classification for a process with multiple production grades [texte imprimé] / Jialin Liu, Auteur . - 2008 . - p. 8250–8262. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8250–8262 Mots-clés : Industrial polyethylene Résumé : In practice, an industrial polyethylene process produces various products, even often developing new production grades for market demand. Therefore, the process has not only multiple operating conditions, but also time-varying characteristics. In addition, the process measurements inevitably are redundant and noisy. It is a challenging problem for on-line classifying the operating conditions in the industrial process. In this paper, principal component analysis (PCA) is applied to the reference data set to reduce the dimensions of variables and eliminate the collinearities among process measurements. Since outliers are inevitable in a real plant data set, they significantly stretch the cluster centers and covariances and reach an unreliable solution. In this paper, the distance-based fuzzy c-means (DFCM) algorithm is proposed. A boundary distance for each cluster is derived for identifying outliers, which should be discarded from the reference data set. Before the on-line classification, the statistic Q and T2 of new data have to be evaluated. If any one of the statistics is out of its control limits, it indicates the new data do not belong to the PCA subspace and they should be collected for the next model update. In this paper, the blockwise recursive formulas for updating the means and covariance matrix are derived. By utilizing the updated means and covariance, a new PCA subspace that accounts for all events is derived recursively. In addition, through rotating and shifting the coordinates of the PCA subspace, the cluster parameters on the new subspace can be directly transferred from the previous one. The proposed method was successfully applied to monitor a polyethylene process with multiple production grades and time-varying characteristics. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0710014

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Dynamic analysis and identification of a wet limestone flue Gas desulfurization pilot plan / A. L. Villanueva Perales in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - P. 8263–8272 Titre : Dynamic analysis and identification of a wet limestone flue Gas desulfurization pilot plan Type de document : texte imprimé Auteurs : A. L. Villanueva Perales, Auteur ; P. Ollero, Auteur ; F. J. Gutiérrez Ortiz, Auteur ; F. Vidal Barrero, Auteur Année de publication : 2008 Article en page(s) : P. 8263–8272 Note générale : Chemical engineering Langues : Anglais (eng) Résumé : In order to meet more stringent SO2 regulations that have come into force recently, the operating conditions of wet limestone flue gas desulfurization (WLFGD) plants must be changed from design conditions to others where a higher SO2 removal is obtained; this results in higher operating costs. Furthermore, because of process disturbances, the SO2 removal target is usually set somewhat higher than necessary to provide a safety margin for meeting SO2 emission limits. Thus, the larger the safety margin, the higher the operating costs. How much larger the safety margin needs to be depends on the proper tuning of the control strategy and dynamic properties of the WLFGD plant to be controlled. Both aspects can only be studied if a dynamic model of the plant is available. However, dynamic modeling of WLFGD plants for control purposes has not been addressed in the literature so far. To deal with with this issue, in this paper we propose an identification methodology for control purposes applicable to full-scale plants. The identification methodology is put into practice in a WLFGD pilot plant, and the empirical dynamic model obtained is suitable for predicting the dynamic behavior of the pilot plant in a wide range of operating conditions. The dynamic behavior of the pilot plant is further analyzed from the perspective of the physical−chemical phenomena of the WLFGD process Note de contenu : Dynamic Analysis wet limestone En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071582x [article] Dynamic analysis and identification of a wet limestone flue Gas desulfurization pilot plan [texte imprimé] / A. L. Villanueva Perales, Auteur ; P. Ollero, Auteur ; F. J. Gutiérrez Ortiz, Auteur ; F. Vidal Barrero, Auteur . - 2008 . - P. 8263–8272. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - P. 8263–8272 Résumé : In order to meet more stringent SO2 regulations that have come into force recently, the operating conditions of wet limestone flue gas desulfurization (WLFGD) plants must be changed from design conditions to others where a higher SO2 removal is obtained; this results in higher operating costs. Furthermore, because of process disturbances, the SO2 removal target is usually set somewhat higher than necessary to provide a safety margin for meeting SO2 emission limits. Thus, the larger the safety margin, the higher the operating costs. How much larger the safety margin needs to be depends on the proper tuning of the control strategy and dynamic properties of the WLFGD plant to be controlled. Both aspects can only be studied if a dynamic model of the plant is available. However, dynamic modeling of WLFGD plants for control purposes has not been addressed in the literature so far. To deal with with this issue, in this paper we propose an identification methodology for control purposes applicable to full-scale plants. The identification methodology is put into practice in a WLFGD pilot plant, and the empirical dynamic model obtained is suitable for predicting the dynamic behavior of the pilot plant in a wide range of operating conditions. The dynamic behavior of the pilot plant is further analyzed from the perspective of the physical−chemical phenomena of the WLFGD process Note de contenu : Dynamic Analysis wet limestone En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071582x

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Gray-box model identification of an integrated plant with recycle / Jay H. Lee in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8273–8281 Titre : Gray-box model identification of an integrated plant with recycle Type de document : texte imprimé Auteurs : Jay H. Lee, Auteur ; Thidarat Tosukhowong, Auteur Année de publication : 2008 Article en page(s) : p. 8273–8281 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Dynamic model Proposed gray-boxi Résumé : The objective of this paper is to propose a systematic method for identifying a dynamic model of an integrated plant with recycle for plantwide optimization and control purposes. We are interested in cases where identification experiment is limited to a period of time much shorter than the plant’s settling time. The method is intended to take advantage of prior knowledge about the plant’s steady-state gains. We use an example of an integrated plant composed of a reactor and a distillation column to illustrate the potential issues and to test the effectiveness of the proposed gray-box identification approach. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071625%2B [article] Gray-box model identification of an integrated plant with recycle [texte imprimé] / Jay H. Lee, Auteur ; Thidarat Tosukhowong, Auteur . - 2008 . - p. 8273–8281. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8273–8281 Mots-clés : Dynamic model Proposed gray-boxi Résumé : The objective of this paper is to propose a systematic method for identifying a dynamic model of an integrated plant with recycle for plantwide optimization and control purposes. We are interested in cases where identification experiment is limited to a period of time much shorter than the plant’s settling time. The method is intended to take advantage of prior knowledge about the plant’s steady-state gains. We use an example of an integrated plant composed of a reactor and a distillation column to illustrate the potential issues and to test the effectiveness of the proposed gray-box identification approach. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071625%2B

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Optimal solution-range analysis in production planning: refinery feedstock selection / Dimitrios K. Varvarezos in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8282–8285 Titre : Optimal solution-range analysis in production planning: refinery feedstock selection Type de document : texte imprimé Auteurs : Dimitrios K. Varvarezos, Auteur Année de publication : 2008 Article en page(s) : p. 8282–8285 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Crude oilAnalysis including all feedstocks Résumé : This paper presents a new way to expand and analyze the optimal solution of a process planning model. Feedstock selection in a refinery is a complex process, accomplished in many steps that typically involve numerous optimization executions that aim at providing a “value” for each potential crude oil feedstock to the refinery for a given operational period. Traditionally, the optimal crude oil slate as determined by the planning system is a point solution that does not provide detailed information regarding potential (finite) changes in the optimal crude oil selection without degradation of the overall plant economics., In this work we define the optimal selection range for each feedstock as the result of a Pareto-type analysis including all feedstocks. Two flexibility indices are defined for each crude oil feed providing a quantitative flexibility metric in the context of optimal economics. The proposed approach provides a useful and practical way to quantitatively evaluate each potential crude feed. This is expressed in terms of an optimal range as defined by the ability of a feedstock to replace and be replaced in the optimal solution without significant economic change. In addition, this analysis provides a map of the optimal surface in terms of near-optimal points around the base solution. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800078e [article] Optimal solution-range analysis in production planning: refinery feedstock selection [texte imprimé] / Dimitrios K. Varvarezos, Auteur . - 2008 . - p. 8282–8285. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8282–8285 Mots-clés : Crude oilAnalysis including all feedstocks Résumé : This paper presents a new way to expand and analyze the optimal solution of a process planning model. Feedstock selection in a refinery is a complex process, accomplished in many steps that typically involve numerous optimization executions that aim at providing a “value” for each potential crude oil feedstock to the refinery for a given operational period. Traditionally, the optimal crude oil slate as determined by the planning system is a point solution that does not provide detailed information regarding potential (finite) changes in the optimal crude oil selection without degradation of the overall plant economics., In this work we define the optimal selection range for each feedstock as the result of a Pareto-type analysis including all feedstocks. Two flexibility indices are defined for each crude oil feed providing a quantitative flexibility metric in the context of optimal economics. The proposed approach provides a useful and practical way to quantitatively evaluate each potential crude feed. This is expressed in terms of an optimal range as defined by the ability of a feedstock to replace and be replaced in the optimal solution without significant economic change. In addition, this analysis provides a map of the optimal surface in terms of near-optimal points around the base solution. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800078e

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Life Cycle Assessment Coupled with Process der Uncertainty for Reduced Environmental Impact: Application to Phosphoric Acid Production / Aarón David Bojarsk in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8286–8300 Titre : Life Cycle Assessment Coupled with Process der Uncertainty for Reduced Environmental Impact: Application to Phosphoric Acid Production Type de document : texte imprimé Auteurs : Aarón David Bojarsk, Auteur ; Gonzalo Guillen-Gosalbez, Auteur ; Laureano Jiménez, Auteur Année de publication : 2008 Article en page(s) : p. 8286–8300 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Phosphoric acid Résumé : One of the most important drawbacks of life cycle assessment (LCA)-related analysis is the generation of reliable data. In the proposed methodology, this drawback is addressed using data from process simulations, based on first-principles models in the LCA calculations. Furthermore, uncertainty that arises from industrial data and a simulation hypothesis are explicitly incorporated, using Monte Carlo sampling, which allows statistical information to be translated into a set of representative scenarios for which the LCA calculations are performed. The combined use of LCA, process simulation, and sampling techniques results in a powerful environmentally conscious quantitative tool whose objective is to guide decision-makers toward the adoption of more-sustainable process alternatives. The main objective of the methodology is to show the main differences between production options. This novel methodology is applied to the specific case of phosphoric acid (PA) production. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8001149 [article] Life Cycle Assessment Coupled with Process der Uncertainty for Reduced Environmental Impact: Application to Phosphoric Acid Production [texte imprimé] / Aarón David Bojarsk, Auteur ; Gonzalo Guillen-Gosalbez, Auteur ; Laureano Jiménez, Auteur . - 2008 . - p. 8286–8300. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8286–8300 Mots-clés : Phosphoric acid Résumé : One of the most important drawbacks of life cycle assessment (LCA)-related analysis is the generation of reliable data. In the proposed methodology, this drawback is addressed using data from process simulations, based on first-principles models in the LCA calculations. Furthermore, uncertainty that arises from industrial data and a simulation hypothesis are explicitly incorporated, using Monte Carlo sampling, which allows statistical information to be translated into a set of representative scenarios for which the LCA calculations are performed. The combined use of LCA, process simulation, and sampling techniques results in a powerful environmentally conscious quantitative tool whose objective is to guide decision-makers toward the adoption of more-sustainable process alternatives. The main objective of the methodology is to show the main differences between production options. This novel methodology is applied to the specific case of phosphoric acid (PA) production. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8001149

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Selection of Third-party service contracts for chemical logistics / Mukta Bansal in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8301–8316 Titre : Selection of Third-party service contracts for chemical logistics Type de document : texte imprimé Auteurs : Mukta Bansal, Auteur ; Iftekhar A. Karimi, Auteur ; Rajagopalan Srinivasan, Auteur Année de publication : 2008 Article en page(s) : p. 8301–8316 Note générale : Chmical engineering Langues : Anglais (eng) Mots-clés : Chemical logistics Résumé : Logistics costs in the chemical and related industries are among the highest in asset-intensive supply chains. Having managed the intraplant logistics well for years, companies are now looking for ways to lower the costs of enterprise-wide logistics by increasingly outsourcing a variety of logistics services to third-party logistics (3PL) firms globally. This paper presents a systematic framework for managing chemical logistics in an integrated manner. It presents a novel approach to represent logistics tasks in terms of recipes and recipe superstructures. Using this representation, it develops a mixed-integer linear programming formulation to fulfill the logistics needs of a global enterprise in terms of 3PL contracts and in-house execution. The goal is to obtain the contracts, and thus the 3PLs, that serve the total needs of a company in an integrated manner and with the minimum cost. Several industry-based examples show the utility of our approach. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800132f [article] Selection of Third-party service contracts for chemical logistics [texte imprimé] / Mukta Bansal, Auteur ; Iftekhar A. Karimi, Auteur ; Rajagopalan Srinivasan, Auteur . - 2008 . - p. 8301–8316. Chmical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8301–8316 Mots-clés : Chemical logistics Résumé : Logistics costs in the chemical and related industries are among the highest in asset-intensive supply chains. Having managed the intraplant logistics well for years, companies are now looking for ways to lower the costs of enterprise-wide logistics by increasingly outsourcing a variety of logistics services to third-party logistics (3PL) firms globally. This paper presents a systematic framework for managing chemical logistics in an integrated manner. It presents a novel approach to represent logistics tasks in terms of recipes and recipe superstructures. Using this representation, it develops a mixed-integer linear programming formulation to fulfill the logistics needs of a global enterprise in terms of 3PL contracts and in-house execution. The goal is to obtain the contracts, and thus the 3PLs, that serve the total needs of a company in an integrated manner and with the minimum cost. Several industry-based examples show the utility of our approach. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800132f

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Effective tuning method for fuzzy PID with internal model control / X. Duan in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8317–8323 Titre : Effective tuning method for fuzzy PID with internal model control Type de document : texte imprimé Auteurs : X. Duan, Auteur ; Han-Xiong Li, Auteur Année de publication : 2008 Article en page(s) : p. 8317–8323 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : The lyapunov stability theory Résumé : An internal model control (IMC) based tuning method is proposed to autotune the fuzzy proportional integral derivative (PID) controller in this paper. An analytical model of the fuzzy PID controller is first derived, which consists of a linear PID controller and a nonlinear compensation item. The nonlinear compensation item can be considered as a process disturbance, and then parameters of the fuzzy PID controller can be analytically determined on the basis of the IMC structure. The stability of the fuzzy PID control system is analyzed using the Lyapunov stability theory. The simulation results demonstrate the effectiveness of the proposed tuning method. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800485j [article] Effective tuning method for fuzzy PID with internal model control [texte imprimé] / X. Duan, Auteur ; Han-Xiong Li, Auteur . - 2008 . - p. 8317–8323. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8317–8323 Mots-clés : The lyapunov stability theory Résumé : An internal model control (IMC) based tuning method is proposed to autotune the fuzzy proportional integral derivative (PID) controller in this paper. An analytical model of the fuzzy PID controller is first derived, which consists of a linear PID controller and a nonlinear compensation item. The nonlinear compensation item can be considered as a process disturbance, and then parameters of the fuzzy PID controller can be analytically determined on the basis of the IMC structure. The stability of the fuzzy PID control system is analyzed using the Lyapunov stability theory. The simulation results demonstrate the effectiveness of the proposed tuning method. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800485j

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parallel hybrid algorithm for process flexibility analysis / Jeonghwa Moon in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8324–8336 Titre : parallel hybrid algorithm for process flexibility analysis Type de document : texte imprimé Auteurs : Jeonghwa Moon, Auteur ; Kedar Kulkarni, Auteur ; Libin Zhang, Auteur Année de publication : 2008 Article en page(s) : p. 8324–8336 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Flexibility analysisHybrid algorithm Résumé : Flexibility analysis is an important task for the optimal design and synthesis of chemical processes with uncertainty. It is a challenging problem because of the discontinuity and nonconvexity of rigorous flexibility programming formulations. In this article, we propose a new parallel hybrid algorithm based on stochastic search in conjunction with a nearest constraint projection technique to numerically solve the flexibility index problem. The proposed method can be applied regardless of the convexity of the design constraints. The stochastic method robustly identifies the global solution without the need for derivative information. The new nearest constraint projection technique is used to handle the constraints of the flexibility index problem in reduced state space. In contrast to existing methods, this technique does not require the addition of artificial variables for active constraints, does not need to have access to explicit analytical forms of the problem formulation or its derivatives, and does not solve for additional artificial variables. Its implementation is well-suited for parallel computing so that computational time can be dramatically reduced. Five applications illustrate the efficacy of the proposed method. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800644n [article] parallel hybrid algorithm for process flexibility analysis [texte imprimé] / Jeonghwa Moon, Auteur ; Kedar Kulkarni, Auteur ; Libin Zhang, Auteur . - 2008 . - p. 8324–8336. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8324–8336 Mots-clés : Flexibility analysisHybrid algorithm Résumé : Flexibility analysis is an important task for the optimal design and synthesis of chemical processes with uncertainty. It is a challenging problem because of the discontinuity and nonconvexity of rigorous flexibility programming formulations. In this article, we propose a new parallel hybrid algorithm based on stochastic search in conjunction with a nearest constraint projection technique to numerically solve the flexibility index problem. The proposed method can be applied regardless of the convexity of the design constraints. The stochastic method robustly identifies the global solution without the need for derivative information. The new nearest constraint projection technique is used to handle the constraints of the flexibility index problem in reduced state space. In contrast to existing methods, this technique does not require the addition of artificial variables for active constraints, does not need to have access to explicit analytical forms of the problem formulation or its derivatives, and does not solve for additional artificial variables. Its implementation is well-suited for parallel computing so that computational time can be dramatically reduced. Five applications illustrate the efficacy of the proposed method. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800644n

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Use of data-driven model to optimize scale-up production of nanosized silver sarticles / Jyh-Shyong Chang in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8337–8346 Titre : Use of data-driven model to optimize scale-up production of nanosized silver sarticles Type de document : texte imprimé Auteurs : Jyh-Shyong Chang, Auteur ; Tzu-Chun Hu, Auteur ; Jiun-kai Tang, Auteur Année de publication : 2008 Article en page(s) : p. 8337–8346 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Synthesis of nanosized Chemical reduction Résumé : Optimization of the synthesis of nanosized silver particles by chemical reduction using formaldehyde in aqueous solution was carried out based on small-scale experimental data (with a 100 cc reaction mixture loaded in a 200 cc beaker and shaken in an isothermal shaker). Effects of the possible processing variables were achieved. In this study, the scale-up production (2 L or more of the reaction mixture) of nanosized silver particles is intended; however, for a scale-up system, the experiments generally require large and expensive resources. To obtain the optimal recipe and operating conditions using limited resources for a scale-up system, an algorithm for extending the identified model built from a small-scale system to a scale-up system was first developed through a numerical example. On the basis of the developed algorithm, 19 experiments were carried out in the scale-up system to achieve the objectives (minimum of the mean particle size of the silver colloid with or without the constraint of conversion of silver nitrate) of the synthesis of nanosized silver particles. With the modeling and optimization method proposed in this work, limited experiments were required, and most of the experiments can produce near on-specification products such that the off-specification products can be minimized En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800345e [article] Use of data-driven model to optimize scale-up production of nanosized silver sarticles [texte imprimé] / Jyh-Shyong Chang, Auteur ; Tzu-Chun Hu, Auteur ; Jiun-kai Tang, Auteur . - 2008 . - p. 8337–8346. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8337–8346 Mots-clés : Synthesis of nanosized Chemical reduction Résumé : Optimization of the synthesis of nanosized silver particles by chemical reduction using formaldehyde in aqueous solution was carried out based on small-scale experimental data (with a 100 cc reaction mixture loaded in a 200 cc beaker and shaken in an isothermal shaker). Effects of the possible processing variables were achieved. In this study, the scale-up production (2 L or more of the reaction mixture) of nanosized silver particles is intended; however, for a scale-up system, the experiments generally require large and expensive resources. To obtain the optimal recipe and operating conditions using limited resources for a scale-up system, an algorithm for extending the identified model built from a small-scale system to a scale-up system was first developed through a numerical example. On the basis of the developed algorithm, 19 experiments were carried out in the scale-up system to achieve the objectives (minimum of the mean particle size of the silver colloid with or without the constraint of conversion of silver nitrate) of the synthesis of nanosized silver particles. With the modeling and optimization method proposed in this work, limited experiments were required, and most of the experiments can produce near on-specification products such that the off-specification products can be minimized En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800345e

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Application of a Temperature-Dependmiempirical thermodynamic ion-exchange model to a multicomponent natural zeolite system / Kathryn A. Mumford in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8347–8354 Titre : Application of a Temperature-Dependmiempirical thermodynamic ion-exchange model to a multicomponent natural zeolite system Type de document : texte imprimé Auteurs : Kathryn A. Mumford, Auteur ; David C. Shallcross, Auteur ; Ian Snape, Auteur ; Geoff W. Stevens, Auteur Année de publication : 2008 Article en page(s) : p. 8347–8354 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Semiempirical thermodynamic Résumé : A recently developed temperature-dependent semiempirical thermodynamic ion-exchange model is used to predict ion-exchange equilibrium behavior of a binary and ternary system onto a natural zeolite material. The ion-exchange system involves the cations ammonium, potassium, and calcium, at chloride concentrations ranging from 0.005 to 0.25 M and temperatures ranging from 4.0 to 40.0 °C ± 0.2 °C. The model describes the ion-exchange behavior well, considering the natural variability of the zeolite material. En ligne : http://pubs.acs.org/toc/iecred/47/21 [article] Application of a Temperature-Dependmiempirical thermodynamic ion-exchange model to a multicomponent natural zeolite system [texte imprimé] / Kathryn A. Mumford, Auteur ; David C. Shallcross, Auteur ; Ian Snape, Auteur ; Geoff W. Stevens, Auteur . - 2008 . - p. 8347–8354. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8347–8354 Mots-clés : Semiempirical thermodynamic Résumé : A recently developed temperature-dependent semiempirical thermodynamic ion-exchange model is used to predict ion-exchange equilibrium behavior of a binary and ternary system onto a natural zeolite material. The ion-exchange system involves the cations ammonium, potassium, and calcium, at chloride concentrations ranging from 0.005 to 0.25 M and temperatures ranging from 4.0 to 40.0 °C ± 0.2 °C. The model describes the ion-exchange behavior well, considering the natural variability of the zeolite material. En ligne : http://pubs.acs.org/toc/iecred/47/21

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Stability and Selectivity of Supported Liquid membranes with Ionicliquids for the separation of organic liquids by vapor permeation in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p 8355–8360 Titre : Stability and Selectivity of Supported Liquid membranes with Ionicliquids for the separation of organic liquids by vapor permeation Type de document : texte imprimé Année de publication : 2008 Article en page(s) : p 8355–8360 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : liquid membranes Cyclohexane systems Résumé : The stability of supported liquid membranes (SLMs) was partially improved by using a room-temperature ionic liquid (RTIL) as the membrane liquid and by employing a vapor permeation process for the separation of toluene/cyclohexane systems and the dehydration of aqueous 1-propanol and aqueous ethanol mixtures. Because the basic characteristics of RTILs are that they have high surface tension and no detectable vapor pressure, the loss of membrane liquid by evaporation was avoided completely. The separation of toluene/cyclohexane mixtures was conducted for as long as 550 h, and the separation factor was kept within the range of 15−25, with the membrane showing good durability in vapor permeation. The use of SLMs with ionic liquids was shown to be a promising method for separating organic/organic and organic/water mixtures. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie7017004 [article] Stability and Selectivity of Supported Liquid membranes with Ionicliquids for the separation of organic liquids by vapor permeation [texte imprimé] . - 2008 . - p 8355–8360. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p 8355–8360 Mots-clés : liquid membranes Cyclohexane systems Résumé : The stability of supported liquid membranes (SLMs) was partially improved by using a room-temperature ionic liquid (RTIL) as the membrane liquid and by employing a vapor permeation process for the separation of toluene/cyclohexane systems and the dehydration of aqueous 1-propanol and aqueous ethanol mixtures. Because the basic characteristics of RTILs are that they have high surface tension and no detectable vapor pressure, the loss of membrane liquid by evaporation was avoided completely. The separation of toluene/cyclohexane mixtures was conducted for as long as 550 h, and the separation factor was kept within the range of 15−25, with the membrane showing good durability in vapor permeation. The use of SLMs with ionic liquids was shown to be a promising method for separating organic/organic and organic/water mixtures. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie7017004

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Detection of Contrabands in cargo containers using a high-speed gas chromatograph with surface acoustic wave sensor / Edward J. Staples in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p 8361–8367 Titre : Detection of Contrabands in cargo containers using a high-speed gas chromatograph with surface acoustic wave sensor Type de document : texte imprimé Auteurs : Edward J. Staples, Auteur ; Shekar Viswanathan, Auteur Année de publication : 2008 Article en page(s) : p 8361–8367 Note générale : Chemical engineerig Langues : Anglais (eng) Mots-clés : Chemical profiling systemExprimental mathodology Résumé : A portable chemical profiling system for cargo containers using a single, uncoated, high Q surface acoustic wave sensor, along with a high-speed chromatograph and column, a programmable gate array microprocessor, and a vapor preconcentrator, is described. This unit provides a recognizable visual vectorial image in N-dimensional space (where N equals the number of sensors) of specific vapor mixtures (fragrances) containing possibly hundreds of different chemical species in 20 s or near real time with picogram sensitivity. This new approach, based upon fast chromatography, which combines the technology with sampling system is proven to solve complex contraband detection and measurement problems with the probability of detection equal to or greater than 90% with a false alarm rate of 1%. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701703y [article] Detection of Contrabands in cargo containers using a high-speed gas chromatograph with surface acoustic wave sensor [texte imprimé] / Edward J. Staples, Auteur ; Shekar Viswanathan, Auteur . - 2008 . - p 8361–8367. Chemical engineerig Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p 8361–8367 Mots-clés : Chemical profiling systemExprimental mathodology Résumé : A portable chemical profiling system for cargo containers using a single, uncoated, high Q surface acoustic wave sensor, along with a high-speed chromatograph and column, a programmable gate array microprocessor, and a vapor preconcentrator, is described. This unit provides a recognizable visual vectorial image in N-dimensional space (where N equals the number of sensors) of specific vapor mixtures (fragrances) containing possibly hundreds of different chemical species in 20 s or near real time with picogram sensitivity. This new approach, based upon fast chromatography, which combines the technology with sampling system is proven to solve complex contraband detection and measurement problems with the probability of detection equal to or greater than 90% with a false alarm rate of 1%. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701703y

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Performance and scale-up of karr reciprocating plate extraction columns / Kathryn H. Smith in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p 8368–8375 Titre : Performance and scale-up of karr reciprocating plate extraction columns Type de document : texte imprimé Auteurs : Kathryn H. Smith, Auteur ; Tim Bowser, Auteur ; Geoff W. Stevens, Auteur Année de publication : 2008 Article en page(s) : p 8368–8375 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hydrodynamic and mass System of kerosene/tributyl phosphate− Résumé : The hydrodynamic and mass transfer performance of Karr reciprocating plate extraction columns with varying column diameters has been presented in order to examine how column performance changes with scale. An ideal liquid system of kerosene/tributyl phosphate−phenol−water was initially studied using a 50 mm diameter Karr column. Correlations were developed to predict the dispersed phase holdup, drop size distribution, and overall mass transfer coefficient over a range of operating conditions. This was followed by column performance studies using a phenolic alkaloid liquid system in Karr columns with diameters of 50, 100, and 300 mm. Overall results showed that there was no significant change in either the dispersed phase holdup or the mass transfer coefficient with column diameter. It was therefore concluded that overall column performance was independent of column diameter and the traditional Karr column scale-up equations were too conservative. This study also showed that factors such as droplet and plate coalescence, contamination of liquid systems, aging of column internals, and variation in physical properties can greatly influence the column’s performance and need to be carefully considered when designing a Karr column. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800581u#afn1 [article] Performance and scale-up of karr reciprocating plate extraction columns [texte imprimé] / Kathryn H. Smith, Auteur ; Tim Bowser, Auteur ; Geoff W. Stevens, Auteur . - 2008 . - p 8368–8375. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p 8368–8375 Mots-clés : Hydrodynamic and mass System of kerosene/tributyl phosphate− Résumé : The hydrodynamic and mass transfer performance of Karr reciprocating plate extraction columns with varying column diameters has been presented in order to examine how column performance changes with scale. An ideal liquid system of kerosene/tributyl phosphate−phenol−water was initially studied using a 50 mm diameter Karr column. Correlations were developed to predict the dispersed phase holdup, drop size distribution, and overall mass transfer coefficient over a range of operating conditions. This was followed by column performance studies using a phenolic alkaloid liquid system in Karr columns with diameters of 50, 100, and 300 mm. Overall results showed that there was no significant change in either the dispersed phase holdup or the mass transfer coefficient with column diameter. It was therefore concluded that overall column performance was independent of column diameter and the traditional Karr column scale-up equations were too conservative. This study also showed that factors such as droplet and plate coalescence, contamination of liquid systems, aging of column internals, and variation in physical properties can greatly influence the column’s performance and need to be carefully considered when designing a Karr column. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800581u#afn1

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Replacement of trays by packingtoincrease the absorption capacity of acetone during cellulose acetate spinning / Roberto Nasser Jr. in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8376–8383 Titre : Replacement of trays by packingtoincrease the absorption capacity of acetone during cellulose acetate spinning Type de document : texte imprimé Auteurs : Roberto Nasser Jr., Auteur Année de publication : 2008 Article en page(s) : p. 8376–8383 Note générale : Chemical engineerng Langues : Anglais (eng) Mots-clés : Acetone absorptionCellulose acetate Résumé : All textile uses of cellulose acetate involve acetone recovery, which, because of safety issues, results in large installations, in order to work with dilute streams. This compromises the efficiency of all of the involved unit operations, in this case, acetone absorption in cold water, acetone distillation, and water chilling, making them more expensive. The present article proposes the improvement of the absorption of acetone in water, traditionally performed with sieve trays, by using structured packing instead. The advantageous implementation was enabled through the utilization of a calculation methodology based on concepts of thermodynamic equilibrium of the binary acetone/water system and empirical relations that allow the evaluation of the hydrodynamics of the proposed modification. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800612e [article] Replacement of trays by packingtoincrease the absorption capacity of acetone during cellulose acetate spinning [texte imprimé] / Roberto Nasser Jr., Auteur . - 2008 . - p. 8376–8383. Chemical engineerng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8376–8383 Mots-clés : Acetone absorptionCellulose acetate Résumé : All textile uses of cellulose acetate involve acetone recovery, which, because of safety issues, results in large installations, in order to work with dilute streams. This compromises the efficiency of all of the involved unit operations, in this case, acetone absorption in cold water, acetone distillation, and water chilling, making them more expensive. The present article proposes the improvement of the absorption of acetone in water, traditionally performed with sieve trays, by using structured packing instead. The advantageous implementation was enabled through the utilization of a calculation methodology based on concepts of thermodynamic equilibrium of the binary acetone/water system and empirical relations that allow the evaluation of the hydrodynamics of the proposed modification. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800612e

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Desulfurization of fuel by extraction with pyridinium-based ionic liquids / Hongshuai Gao in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8384–8388 Titre : Desulfurization of fuel by extraction with pyridinium-based ionic liquids Type de document : texte imprimé Auteurs : Hongshuai Gao, Auteur ; Mingfang Luo, Auteur ; Jianmin Xing, Auteur Année de publication : 2008 Article en page(s) : p. 8384–8388 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Pyridinium-based ionic liquids Résumé : The pyridinium-based ionic liquids (ILs) N-butylpyridinium tetrafluoroborate ([BPy][BF4]), N-hexylpyridinium tetrafluoroborate ([HPy][BF4]), and N-octylpyridinium tetrafluoroborate ([OPy][BF4]) were found to be effective for the selective removal of aromatic heterocyclic sulfur compounds from diesel at room temperature. The results suggested that the structure and size of the cation greatly affect the extractive performance of ILs. The extractive performance using pyridinium-based ILs followed the order [BPy][BF4] En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800739w [article] Desulfurization of fuel by extraction with pyridinium-based ionic liquids [texte imprimé] / Hongshuai Gao, Auteur ; Mingfang Luo, Auteur ; Jianmin Xing, Auteur . - 2008 . - p. 8384–8388. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8384–8388 Mots-clés : Pyridinium-based ionic liquids Résumé : The pyridinium-based ionic liquids (ILs) N-butylpyridinium tetrafluoroborate ([BPy][BF4]), N-hexylpyridinium tetrafluoroborate ([HPy][BF4]), and N-octylpyridinium tetrafluoroborate ([OPy][BF4]) were found to be effective for the selective removal of aromatic heterocyclic sulfur compounds from diesel at room temperature. The results suggested that the structure and size of the cation greatly affect the extractive performance of ILs. The extractive performance using pyridinium-based ILs followed the order [BPy][BF4] En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800739w

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Binary andternaryphasediagrams of benzene, hexafluorobenzene, and ionic liquid [emim][Tf2N] using equations of state / A. Yokozeki in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8389–8395 Titre : Binary andternaryphasediagrams of benzene, hexafluorobenzene, and ionic liquid [emim][Tf2N] using equations of state Type de document : texte imprimé Auteurs : A. Yokozeki, Auteur ; Mark B. Shiflett, Auteur Année de publication : 2008 Article en page(s) : p. 8389–8395 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : System of benzeneIonic liquid, solubility Résumé : A binary system of benzene and hexafluorobenzene is known as a system with famous double azeotropes (minimum-and-maximum pressure azeotropes at the isothermal VLE (vapor−liquid equilibrium)). In order to understand how these azeotropic behaviors will be affected by interactions with an ionic liquid, solubility experiments for benzene + ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [emim][Tf2N], and hexafluorobenzene + [emim][Tf2N] systems have been carried out at temperatures of about 283, 298, and 318 K. Both binary systems show immisciblity gaps with concentration ranges from about 77 to 100 and from about 66 to 100 mol % for benzene and hexafluorobenzene systems, respectively. The observed solubility data have been used to develop equation-of-state (EOS) models (with a generic Redlich−Kwong cubic equation) for these binary systems. As for the binary system of benzene and hexafluorobenzene, VLE data in the literature have been employed to develop the EOS model. Thus, binary and ternary phase diagrams for the present three components have been constructed using the present binary interaction parameters. Then, extractive separations of the azeotropes are discussed based on the present EOS model. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800754u [article] Binary andternaryphasediagrams of benzene, hexafluorobenzene, and ionic liquid [emim][Tf2N] using equations of state [texte imprimé] / A. Yokozeki, Auteur ; Mark B. Shiflett, Auteur . - 2008 . - p. 8389–8395. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8389–8395 Mots-clés : System of benzeneIonic liquid, solubility Résumé : A binary system of benzene and hexafluorobenzene is known as a system with famous double azeotropes (minimum-and-maximum pressure azeotropes at the isothermal VLE (vapor−liquid equilibrium)). In order to understand how these azeotropic behaviors will be affected by interactions with an ionic liquid, solubility experiments for benzene + ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [emim][Tf2N], and hexafluorobenzene + [emim][Tf2N] systems have been carried out at temperatures of about 283, 298, and 318 K. Both binary systems show immisciblity gaps with concentration ranges from about 77 to 100 and from about 66 to 100 mol % for benzene and hexafluorobenzene systems, respectively. The observed solubility data have been used to develop equation-of-state (EOS) models (with a generic Redlich−Kwong cubic equation) for these binary systems. As for the binary system of benzene and hexafluorobenzene, VLE data in the literature have been employed to develop the EOS model. Thus, binary and ternary phase diagrams for the present three components have been constructed using the present binary interaction parameters. Then, extractive separations of the azeotropes are discussed based on the present EOS model. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800754u

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Room temperature ionic liquids for mercury capture from flue gas / Lei Ji in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8396–8400 Titre : Room temperature ionic liquids for mercury capture from flue gas Type de document : texte imprimé Auteurs : Lei Ji, Auteur ; Stephen W Thiel, Auteur ; neville G. Pinto, Auteur Année de publication : 2008 Article en page(s) : p. 8396–8400 Note générale : Chemical engineering Langues : Anglais (eng) Résumé : Six room temperature ionic liquids (RTILs) were synthesized and tested as coatings for adsorbents for mercury capture from nitrogen at 160 °C. All six RTILs were thermally stable to temperatures above 160 °C. These RTILs were coated on mesoporous silica gel, and the fixed-bed mercury capture characteristics of these adsorbents were observed at 160 °C. Hg0 capture appears to result from the formation of a complex involving Hg0 and ions in the RTIL complex, and not from oxidation by the RTIL. The high observed oxidized mercury capacity for Cl−-based RTILs is believed to be due to greater dissociation of HgCl2 in the RTILs that incorporate chloride anion. The higher hydrogen-bond basicity and dipolarity of these RTILs might underlie improved HgCl2 dissociation. [bmim]Cl was identified as a promising RTIL for the simultaneous capture of elemental and oxidized mercury from the gas phase. A nanostructured chelating adsorbent with a coating of 25 wt % [bmim]Cl has an elemental mercury capacity of 10 mg/g and an oxidized mercury capacity of at least 38 mg/g. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8008023 [article] Room temperature ionic liquids for mercury capture from flue gas [texte imprimé] / Lei Ji, Auteur ; Stephen W Thiel, Auteur ; neville G. Pinto, Auteur . - 2008 . - p. 8396–8400. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8396–8400 Résumé : Six room temperature ionic liquids (RTILs) were synthesized and tested as coatings for adsorbents for mercury capture from nitrogen at 160 °C. All six RTILs were thermally stable to temperatures above 160 °C. These RTILs were coated on mesoporous silica gel, and the fixed-bed mercury capture characteristics of these adsorbents were observed at 160 °C. Hg0 capture appears to result from the formation of a complex involving Hg0 and ions in the RTIL complex, and not from oxidation by the RTIL. The high observed oxidized mercury capacity for Cl−-based RTILs is believed to be due to greater dissociation of HgCl2 in the RTILs that incorporate chloride anion. The higher hydrogen-bond basicity and dipolarity of these RTILs might underlie improved HgCl2 dissociation. [bmim]Cl was identified as a promising RTIL for the simultaneous capture of elemental and oxidized mercury from the gas phase. A nanostructured chelating adsorbent with a coating of 25 wt % [bmim]Cl has an elemental mercury capacity of 10 mg/g and an oxidized mercury capacity of at least 38 mg/g. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8008023

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Group contribution prediction of vapor pressure with statistical associating fluid theory, perturbed-chain statistical associating fluid theory, and elliott−suresh−donohue equations of state / Fateme Sadat Emami in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8401–8411 Titre : Group contribution prediction of vapor pressure with statistical associating fluid theory, perturbed-chain statistical associating fluid theory, and elliott−suresh−donohue equations of state Type de document : texte imprimé Auteurs : Fateme Sadat Emami, Auteur ; Amir Vahid, Auteur ; J. Richard Elliott, Auteur Année de publication : 2008 Article en page(s) : p. 8401–8411 Note générale : Chemical engineering Langues : Anglais (eng) Résumé : The group contribution methodology developed by Elliott and Natarajan has been extended to the statistical associating fluid theory (SAFT) and perturbed-chain statistical associating fluid theory (PC-SAFT) equations of state (EOS). Thermodynamic properties were correlated and predicted for a database of 878 compounds, including associating compounds. Association contributions were treated with Wertheim’s theory. The database covers 19 chemical families including hydrocarbons, cyclic hydrocarbons, aromatic hydrocarbons, alcohols, amines, nitriles, thiols, sulfides, aldehydes, ketones, esters, ethers, halocarbons, and silicones. The present group contribution (GC) method was developed in two stages. Initially, pure component parameters of each EOS were obtained by matching their boiling temperatures at 10 or 760 mmHg and available GC estimates of solubility parameter and liquid density, while applying standard hydrogen-bonding parameters. Then, group contributions were regressed for the shape factor parameters of each EOS. Group contributions are presented for 84 first-order functional groups (FOG). Given the GC shape factors, the same GC estimates of solubility parameter and liquid density can be applied to estimate all EOS parameters on a GC basis. The resulting correlation enables three-parameter corresponding states predictions without any experimental data. A byproduct of the correlation for equation of state parameters is the capability to predict vapor pressure only on the basis of chemical structure. This capability was evaluated by computing the vapor pressures at 10, 100, and 760 mmHg. On the basis of the present work, vapor pressure average absolute percent deviations (P AAD%) were 36% for Elliott−Suresh−Donohue (ESD) EOS, 65% for SAFT, 32% PC-SAFT. For comparison, the first- and second-order groups (FOG and SOG) provided by Tihic et al. (for simplified PC-SAFT) have been applied to ∼650 nonassociating compounds. The resulting P AAD% were 53% for Tihic FOG and 42% for Tihic SOG. An alternative characterization of accuracy is the average absolute deviation (|ΔT|) between experimental and calculated saturated temperature. These were 8, 12, 8, 10, and 9 K for ESD, SAFT, PC-SAFT, Tihic FOG, and Tihic SOG equations, respectively. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800329r [article] Group contribution prediction of vapor pressure with statistical associating fluid theory, perturbed-chain statistical associating fluid theory, and elliott−suresh−donohue equations of state [texte imprimé] / Fateme Sadat Emami, Auteur ; Amir Vahid, Auteur ; J. Richard Elliott, Auteur . - 2008 . - p. 8401–8411. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8401–8411 Résumé : The group contribution methodology developed by Elliott and Natarajan has been extended to the statistical associating fluid theory (SAFT) and perturbed-chain statistical associating fluid theory (PC-SAFT) equations of state (EOS). Thermodynamic properties were correlated and predicted for a database of 878 compounds, including associating compounds. Association contributions were treated with Wertheim’s theory. The database covers 19 chemical families including hydrocarbons, cyclic hydrocarbons, aromatic hydrocarbons, alcohols, amines, nitriles, thiols, sulfides, aldehydes, ketones, esters, ethers, halocarbons, and silicones. The present group contribution (GC) method was developed in two stages. Initially, pure component parameters of each EOS were obtained by matching their boiling temperatures at 10 or 760 mmHg and available GC estimates of solubility parameter and liquid density, while applying standard hydrogen-bonding parameters. Then, group contributions were regressed for the shape factor parameters of each EOS. Group contributions are presented for 84 first-order functional groups (FOG). Given the GC shape factors, the same GC estimates of solubility parameter and liquid density can be applied to estimate all EOS parameters on a GC basis. The resulting correlation enables three-parameter corresponding states predictions without any experimental data. A byproduct of the correlation for equation of state parameters is the capability to predict vapor pressure only on the basis of chemical structure. This capability was evaluated by computing the vapor pressures at 10, 100, and 760 mmHg. On the basis of the present work, vapor pressure average absolute percent deviations (P AAD%) were 36% for Elliott−Suresh−Donohue (ESD) EOS, 65% for SAFT, 32% PC-SAFT. For comparison, the first- and second-order groups (FOG and SOG) provided by Tihic et al. (for simplified PC-SAFT) have been applied to ∼650 nonassociating compounds. The resulting P AAD% were 53% for Tihic FOG and 42% for Tihic SOG. An alternative characterization of accuracy is the average absolute deviation (|ΔT|) between experimental and calculated saturated temperature. These were 8, 12, 8, 10, and 9 K for ESD, SAFT, PC-SAFT, Tihic FOG, and Tihic SOG equations, respectively. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800329r

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Thermal decomposition of waste linear alkylbenzene sulfonate / Hyung Ju Lee in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8412–8415 Titre : Thermal decomposition of waste linear alkylbenzene sulfonate Type de document : texte imprimé Auteurs : Hyung Ju Lee, Auteur ; Kyun Young Park, Auteur ; Monn surk-silk, Auteur Année de publication : 2008 Article en page(s) : p. 8412–8415 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : thermal decompositionlinear alkylbenzene Résumé : A thermal decomposition is proposed to convert a waste linear alkylbenzene sulfonate (LAS) into a solid material that is environmentally more favorable and disposable at a lower cost. The waste LAS is a viscous liquid containing sulfur as high as 13.3 wt %. The waste LAS was heated in a nitrogen atmosphere at 200−300 °C for 1−4 h. The thermal treatment at 250 °C for 2 h decomposed the waste into vapors and a solid material or residue, 2.0 wt % in sulfur content. The vapors were cooled with water to form two condensate layers in the receiving cylinder. The upper layer was identified to be a linear alkylbenzene (LAB) and the lower one a mixture of water and organic sulfur oxy compounds. The uncondensed vapor that left the condenser was determined to be a mixture of SO2, SO3, and H2SO4. A material balance shows that the mass of the waste LAS charged was distributed in the decomposition products as follows: the solid residue, 65.3%; the LAB, 5.6%; the mixture of water and organic sulfur compounds, 5.6%; the mixture of SO2, SO3, and H2SO4, 21.5%; unidentifiable loss, 2.0%. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800382n [article] Thermal decomposition of waste linear alkylbenzene sulfonate [texte imprimé] / Hyung Ju Lee, Auteur ; Kyun Young Park, Auteur ; Monn surk-silk, Auteur . - 2008 . - p. 8412–8415. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8412–8415 Mots-clés : thermal decompositionlinear alkylbenzene Résumé : A thermal decomposition is proposed to convert a waste linear alkylbenzene sulfonate (LAS) into a solid material that is environmentally more favorable and disposable at a lower cost. The waste LAS is a viscous liquid containing sulfur as high as 13.3 wt %. The waste LAS was heated in a nitrogen atmosphere at 200−300 °C for 1−4 h. The thermal treatment at 250 °C for 2 h decomposed the waste into vapors and a solid material or residue, 2.0 wt % in sulfur content. The vapors were cooled with water to form two condensate layers in the receiving cylinder. The upper layer was identified to be a linear alkylbenzene (LAB) and the lower one a mixture of water and organic sulfur oxy compounds. The uncondensed vapor that left the condenser was determined to be a mixture of SO2, SO3, and H2SO4. A material balance shows that the mass of the waste LAS charged was distributed in the decomposition products as follows: the solid residue, 65.3%; the LAB, 5.6%; the mixture of water and organic sulfur compounds, 5.6%; the mixture of SO2, SO3, and H2SO4, 21.5%; unidentifiable loss, 2.0%. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800382n

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Thermodynamic consistency test of vapor−liquid equilibrium data for mixtures containing ionic liquids / José O. Valderrama in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8416–8422 Titre : Thermodynamic consistency test of vapor−liquid equilibrium data for mixtures containing ionic liquids Type de document : texte imprimé Auteurs : José O. Valderrama, Auteur ; Alfonso Reátegui, Auteur ; Wilson W. Sanga, Auteur Année de publication : 2008 Article en page(s) : p. 8416–8422 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Thermodynamicionic liquid Résumé : Vapor−liquid equilibrium of eight binary mixtures containing an ionic liquid and carbon dioxide have been tested for thermodynamic consistency. A method proposed by one of the authors has been modified to be applied to this special situation in which the gas phase contains practically one component (carbon dioxide) while the liquid phase contains both components in a wide concentration range. The method is based on the Gibbs−Duhem equation and on appropriate combination of equations of state, mixing rules, and combining rules. The Peng−Robinson equation of state with the Wong−Sandler mixing rules including the Van Laar model for the excess Gibbs free energy required in the mixing rules, are used. The experimental data were obtained from literature sources, and the adjustable parameters were found by minimizing the errors between predicted and experimental bubble pressure. It is shown that the proposed modified consistency test is accurate enough to decide about the thermodynamic consistency of this type of data. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800763x [article] Thermodynamic consistency test of vapor−liquid equilibrium data for mixtures containing ionic liquids [texte imprimé] / José O. Valderrama, Auteur ; Alfonso Reátegui, Auteur ; Wilson W. Sanga, Auteur . - 2008 . - p. 8416–8422. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8416–8422 Mots-clés : Thermodynamicionic liquid Résumé : Vapor−liquid equilibrium of eight binary mixtures containing an ionic liquid and carbon dioxide have been tested for thermodynamic consistency. A method proposed by one of the authors has been modified to be applied to this special situation in which the gas phase contains practically one component (carbon dioxide) while the liquid phase contains both components in a wide concentration range. The method is based on the Gibbs−Duhem equation and on appropriate combination of equations of state, mixing rules, and combining rules. The Peng−Robinson equation of state with the Wong−Sandler mixing rules including the Van Laar model for the excess Gibbs free energy required in the mixing rules, are used. The experimental data were obtained from literature sources, and the adjustable parameters were found by minimizing the errors between predicted and experimental bubble pressure. It is shown that the proposed modified consistency test is accurate enough to decide about the thermodynamic consistency of this type of data. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800763x

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Analysis of the acceleration region in a circulating fluidized bed riser operating above fast fluidization velocities / Esmail R. Monazam in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8423–8429 Titre : Analysis of the acceleration region in a circulating fluidized bed riser operating above fast fluidization velocities Type de document : texte imprimé Auteurs : Esmail R. Monazam, Auteur ; Lawrence J. Shadle, Auteur Année de publication : 2008 Article en page(s) : p. 8423–8429 Note générale : Chmical engineering Langues : Anglais (eng) Mots-clés : Analysis of the acceleration Résumé : In commercial circulating fluidized bed (CFB) processes the acceleration zone greatly contributes to solids mixing, gas and solids dispersion, and particle residence times. A new analysis was developed to describe the relative gas−solids concentration in the acceleration region of a transport system with air as the fluidizing agent for Geldart-type B particles. A theoretical expression was derived from a drag relationship and momentum and continuity equations to describe the evolution of the gas−solids profile along the axial direction. The acceleration zone was characterized using nondimensional analysis of the continuum equations (balances of masses and momenta) that described multiphase flows. In addition to acceleration length, the boundary condition for the solids fraction at the bottom of the riser and the fully developed regions were measured using an industrial scale CFB of 0.3 m diameter and 15 m tall. The operating factors affecting the flow development in the acceleration region were determined for three materials of various sizes and densities in core annular and dilute regimes of the riser. Performance data were taken from statistically designed experiments over a wide range of Fr (0.5−39), Re (8−600), Ar (29−3600), load ratio (0.2−28), riser to particle diameter ratio (375−5000), and gas to solids density ratio (138−1381). In this one-dimensional system of equations, velocities and solid fractions were assumed to be constant over any cross section. The model and engineering correlations were compared with literature expressions to assess their validity and range of applicability. These expressions can be used as tools for simulation and design of a CFB riser and can also be easily coupled to a kinetics model for process simulation. [article] Analysis of the acceleration region in a circulating fluidized bed riser operating above fast fluidization velocities [texte imprimé] / Esmail R. Monazam, Auteur ; Lawrence J. Shadle, Auteur . - 2008 . - p. 8423–8429. Chmical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8423–8429 Mots-clés : Analysis of the acceleration Résumé : In commercial circulating fluidized bed (CFB) processes the acceleration zone greatly contributes to solids mixing, gas and solids dispersion, and particle residence times. A new analysis was developed to describe the relative gas−solids concentration in the acceleration region of a transport system with air as the fluidizing agent for Geldart-type B particles. A theoretical expression was derived from a drag relationship and momentum and continuity equations to describe the evolution of the gas−solids profile along the axial direction. The acceleration zone was characterized using nondimensional analysis of the continuum equations (balances of masses and momenta) that described multiphase flows. In addition to acceleration length, the boundary condition for the solids fraction at the bottom of the riser and the fully developed regions were measured using an industrial scale CFB of 0.3 m diameter and 15 m tall. The operating factors affecting the flow development in the acceleration region were determined for three materials of various sizes and densities in core annular and dilute regimes of the riser. Performance data were taken from statistically designed experiments over a wide range of Fr (0.5−39), Re (8−600), Ar (29−3600), load ratio (0.2−28), riser to particle diameter ratio (375−5000), and gas to solids density ratio (138−1381). In this one-dimensional system of equations, velocities and solid fractions were assumed to be constant over any cross section. The model and engineering correlations were compared with literature expressions to assess their validity and range of applicability. These expressions can be used as tools for simulation and design of a CFB riser and can also be easily coupled to a kinetics model for process simulation.

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Energy saving in papermaking through filler addition / Chunxu Dong in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8430–8435 Titre : Energy saving in papermaking through filler addition Type de document : texte imprimé Auteurs : Chunxu Dong, Auteur ; Delong Song, Auteur ; Timothy Patterson, Auteur Année de publication : 2008 Article en page(s) : p. 8430–8435 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : papermakingenergy savings. Résumé : The main purposes of filler addition in papermaking are to improve paper properties and reduce cost. The cost reduction is attributed to the low cost of the filler itself and to the energy savings that occur during the papermaking process. In this work, the effects of clay filler addition on the energy savings during the papermaking process, including water drainage, pressing, and drying, were systematically investigated. Experimental results indicated that the addition of filler could dramatically increase the drainage rate and the water removal rates during pressing and drying. With 20% filler addition, the drainage time decreased by 20% compared to the unfilled paper. At a filler content of 23%, the solids content of the handsheets after pressing increased at least 5 absolute points, and the drying rates increased by 20%. All these improvements can offer considerable benefits for paper mills, including enhanced machine speeds and large energy savings. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8011159 [article] Energy saving in papermaking through filler addition [texte imprimé] / Chunxu Dong, Auteur ; Delong Song, Auteur ; Timothy Patterson, Auteur . - 2008 . - p. 8430–8435. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8430–8435 Mots-clés : papermakingenergy savings. Résumé : The main purposes of filler addition in papermaking are to improve paper properties and reduce cost. The cost reduction is attributed to the low cost of the filler itself and to the energy savings that occur during the papermaking process. In this work, the effects of clay filler addition on the energy savings during the papermaking process, including water drainage, pressing, and drying, were systematically investigated. Experimental results indicated that the addition of filler could dramatically increase the drainage rate and the water removal rates during pressing and drying. With 20% filler addition, the drainage time decreased by 20% compared to the unfilled paper. At a filler content of 23%, the solids content of the handsheets after pressing increased at least 5 absolute points, and the drying rates increased by 20%. All these improvements can offer considerable benefits for paper mills, including enhanced machine speeds and large energy savings. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8011159

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Improved hydrodynamic model for wetting Efficiency, pressure drop, and liquid hjoldup in trickle-bed reactors / Katja Lappalainen in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8436–8444 Titre : Improved hydrodynamic model for wetting Efficiency, pressure drop, and liquid hjoldup in trickle-bed reactors Type de document : texte imprimé Auteurs : Katja Lappalainen, Auteur ; Ville Alopaeus, Auteur ; Mikko Manninen, Auteur Année de publication : 2008 Article en page(s) : p. 8436–8444 Note générale : Chemical engineeing Langues : Anglais (eng) Mots-clés : Improved hydrodynamic Résumé : An improved hydrodynamic model is developed for estimating wetting efficiency, pressure drop, and liquid holdup in trickle-bed reactors. The model is based on the hydrodynamic model presented in Alopaeus et al. [Alopaeus, V.; Hynynen, K.; Aittamaa, J.; Manninen, M. Modeling of Gas−Liquid Packed-Bed Reactor with Momentum Equations and Local Interactions Closures. Ind. Eng. Chem. Res. 2006, 45, 8189.], which is extended to take into account partial wetting of the packing. In addition, the applicability of the 1D model for three-dimensional situations is considered in the process of model development. The wetting efficiency model is formulated on the basis of dimensional analysis and carrying out systematic tests with varying combinations of dimensionless groups. In addition, the wetting efficiency model is not evaluated solely on the wetting efficiency data, but also it is tested systematically with the hydrodynamic model. Furthermore the consistency of the model characteristics to common experimental observations is discussed. Finally, the model’s ability to predict wetting efficiency, dimensionless pressure drop, and liquid saturation was compared to other existing models and improvements were found in all areas. The resulting hydrodynamic model can be used equally as a tool for design and modeling of large scale industrial reactors as well as a tool for complicated three-dimensional simulations. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8003754 [article] Improved hydrodynamic model for wetting Efficiency, pressure drop, and liquid hjoldup in trickle-bed reactors [texte imprimé] / Katja Lappalainen, Auteur ; Ville Alopaeus, Auteur ; Mikko Manninen, Auteur . - 2008 . - p. 8436–8444. Chemical engineeing Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8436–8444 Mots-clés : Improved hydrodynamic Résumé : An improved hydrodynamic model is developed for estimating wetting efficiency, pressure drop, and liquid holdup in trickle-bed reactors. The model is based on the hydrodynamic model presented in Alopaeus et al. [Alopaeus, V.; Hynynen, K.; Aittamaa, J.; Manninen, M. Modeling of Gas−Liquid Packed-Bed Reactor with Momentum Equations and Local Interactions Closures. Ind. Eng. Chem. Res. 2006, 45, 8189.], which is extended to take into account partial wetting of the packing. In addition, the applicability of the 1D model for three-dimensional situations is considered in the process of model development. The wetting efficiency model is formulated on the basis of dimensional analysis and carrying out systematic tests with varying combinations of dimensionless groups. In addition, the wetting efficiency model is not evaluated solely on the wetting efficiency data, but also it is tested systematically with the hydrodynamic model. Furthermore the consistency of the model characteristics to common experimental observations is discussed. Finally, the model’s ability to predict wetting efficiency, dimensionless pressure drop, and liquid saturation was compared to other existing models and improvements were found in all areas. The resulting hydrodynamic model can be used equally as a tool for design and modeling of large scale industrial reactors as well as a tool for complicated three-dimensional simulations. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8003754

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Dynamic parameters estimation method: advanced manometric temperature measurement approach for freeze-drying monitoring of pharmaceutical solutions / Salvatore A. Velardi in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8445–8457 Titre : Dynamic parameters estimation method: advanced manometric temperature measurement approach for freeze-drying monitoring of pharmaceutical solutions Type de document : texte imprimé Auteurs : Salvatore A. Velardi, Auteur ; Valeria Rasetto, Auteur ; Antonello A. Barresi, Auteur Année de publication : 2008 Article en page(s) : p. 8445–8457 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : The dynamic parameters technique for the freeze-drying Résumé : The aim of this paper is to describe and validate the dynamic parameters estimation (DPE) method, a noninvasive in-line monitoring technique for the freeze-drying process of pharmaceuticals that only requires pressure measurement; simulations and experimental data of pharmaceutical solutions in vials are used to this purpose. This method has to be considered as an improvement of analogous techniques, such as the manometric temperature measurement (MTM) method, which are also based on the pressure rise analysis concept. The proposed approach is able to estimate not only the temperature profile inside the frozen product at any time during the pressure rise test, but also the position of the moving interface of sublimation, the external heat transfer coefficient, and the effective diffusivity coefficient in the dried product, which are necessary for a predictive model-based control algorithm. Fairly good estimations of the product temperature and of the transport parameters, as well as of the position of the interface of sublimation, which is directly related to the state of progression of the primary drying phase, are obtained along almost all the primary drying phase. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie7017433 [article] Dynamic parameters estimation method: advanced manometric temperature measurement approach for freeze-drying monitoring of pharmaceutical solutions [texte imprimé] / Salvatore A. Velardi, Auteur ; Valeria Rasetto, Auteur ; Antonello A. Barresi, Auteur . - 2008 . - p. 8445–8457. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8445–8457 Mots-clés : The dynamic parameters technique for the freeze-drying Résumé : The aim of this paper is to describe and validate the dynamic parameters estimation (DPE) method, a noninvasive in-line monitoring technique for the freeze-drying process of pharmaceuticals that only requires pressure measurement; simulations and experimental data of pharmaceutical solutions in vials are used to this purpose. This method has to be considered as an improvement of analogous techniques, such as the manometric temperature measurement (MTM) method, which are also based on the pressure rise analysis concept. The proposed approach is able to estimate not only the temperature profile inside the frozen product at any time during the pressure rise test, but also the position of the moving interface of sublimation, the external heat transfer coefficient, and the effective diffusivity coefficient in the dried product, which are necessary for a predictive model-based control algorithm. Fairly good estimations of the product temperature and of the transport parameters, as well as of the position of the interface of sublimation, which is directly related to the state of progression of the primary drying phase, are obtained along almost all the primary drying phase. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie7017433

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Analysis of particle segregation and intermixing in solid−liquid fluidized beds / Prakash V Chavan in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8458–8470 Titre : Analysis of particle segregation and intermixing in solid−liquid fluidized beds Type de document : texte imprimé Auteurs : Prakash V Chavan, Auteur ; Jyeshtharaj B. Joshi, Auteur Année de publication : 2008 Article en page(s) : p. 8458–8470 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Analysis of particl Résumé : Particle segregation and intermixing have been studied in 50 mm i.d. and 1.2 m long solid−liquid fluidized bed (SLFB). An ion-exchange resin was used as a solid phase in five size ranges with average particle sizes (dry basis) of 427, 500, 605, 725, and 855 μm. Expansion characteristics of beds were investigated separately for all the particle sizes. The expansion characteristics were also investigated using 2, 3, 4, and 5 sizes having all the combinations among 427, 500, 605, 725, and 855 μm. In all cases, the concentration profiles of the individual sizes were measured along the bed height. The segregation velocity of dense and light particle was predicted and compared with experimental results for binary mixtures. Criteria have been developed for segregation/intermixing in laminar (Re∞ 500) regimes for binary particle systems. The solid dispersion coefficient has also been evaluated for each particle size present in the mixture of particles of different sizes at given operating conditions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800504z [article] Analysis of particle segregation and intermixing in solid−liquid fluidized beds [texte imprimé] / Prakash V Chavan, Auteur ; Jyeshtharaj B. Joshi, Auteur . - 2008 . - p. 8458–8470. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8458–8470 Mots-clés : Analysis of particl Résumé : Particle segregation and intermixing have been studied in 50 mm i.d. and 1.2 m long solid−liquid fluidized bed (SLFB). An ion-exchange resin was used as a solid phase in five size ranges with average particle sizes (dry basis) of 427, 500, 605, 725, and 855 μm. Expansion characteristics of beds were investigated separately for all the particle sizes. The expansion characteristics were also investigated using 2, 3, 4, and 5 sizes having all the combinations among 427, 500, 605, 725, and 855 μm. In all cases, the concentration profiles of the individual sizes were measured along the bed height. The segregation velocity of dense and light particle was predicted and compared with experimental results for binary mixtures. Criteria have been developed for segregation/intermixing in laminar (Re∞ 500) regimes for binary particle systems. The solid dispersion coefficient has also been evaluated for each particle size present in the mixture of particles of different sizes at given operating conditions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800504z

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Reactions of organic sulfur and nitrogen compounds in the fCC pretreater and the FCC unit / Peter Ø. Vistisen in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8471–8477 Titre : Reactions of organic sulfur and nitrogen compounds in the fCC pretreater and the FCC unit Type de document : texte imprimé Auteurs : Peter Ø. Vistisen, Auteur ; Per Zeuthen, Auteur Année de publication : 2008 Article en page(s) : p. 8471–8477 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hydrotreating Résumé : The effect of hydrotreating VGO (FCC pretreatment) at different severities was examined with respect to FCC performance. Furthermore, the reaction mechanisms for conversion of the organic sulfur and nitrogen compounds found in the pretreated FCC feedstocks during FCC processing were studied. The studies were carried out under realistic conditions in a large pilot plant hydrotreating unit and in an FCC pilot plant operating with a circulating catalyst. It was found that the sulfur compounds in the FCC gasoline (i.e., thiophenes and benzothiophenes) were formed from recombination reactions between H2S and olefins generated in the FCC unit. Similarly, the nitrogen compounds found in the FCC gasoline (i.e., anilines and indoles) were formed from recombination reactions between ammonia and olefins. These results show that the sulfur and nitrogen compounds in the FCC gasoline are mostly the same with only minor differences in the relative concentration of the individual compound. This phenomenon is not dependent on the feed charged to the FCC unit but is a result of equilibrium reactions between olefins, H2S and ammonia, respectively, and the temperature in the FCC reactor. [article] Reactions of organic sulfur and nitrogen compounds in the fCC pretreater and the FCC unit [texte imprimé] / Peter Ø. Vistisen, Auteur ; Per Zeuthen, Auteur . - 2008 . - p. 8471–8477. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8471–8477 Mots-clés : Hydrotreating Résumé : The effect of hydrotreating VGO (FCC pretreatment) at different severities was examined with respect to FCC performance. Furthermore, the reaction mechanisms for conversion of the organic sulfur and nitrogen compounds found in the pretreated FCC feedstocks during FCC processing were studied. The studies were carried out under realistic conditions in a large pilot plant hydrotreating unit and in an FCC pilot plant operating with a circulating catalyst. It was found that the sulfur compounds in the FCC gasoline (i.e., thiophenes and benzothiophenes) were formed from recombination reactions between H2S and olefins generated in the FCC unit. Similarly, the nitrogen compounds found in the FCC gasoline (i.e., anilines and indoles) were formed from recombination reactions between ammonia and olefins. These results show that the sulfur and nitrogen compounds in the FCC gasoline are mostly the same with only minor differences in the relative concentration of the individual compound. This phenomenon is not dependent on the feed charged to the FCC unit but is a result of equilibrium reactions between olefins, H2S and ammonia, respectively, and the temperature in the FCC reactor.

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Electrochemical oxidation of refractory organics wastewater and chemical oxygen demand (COD) Removal under Extremely Mild Condition / Bo Wang in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8478–8483 Titre : Electrochemical oxidation of refractory organics wastewater and chemical oxygen demand (COD) Removal under Extremely Mild Condition Type de document : texte imprimé Auteurs : Bo Wang, Auteur ; Xin Chang, Auteur ; Hongzhu Ma, Auteur Année de publication : 2008 Article en page(s) : p. 8478–8483 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Wastewater causes Pollution Résumé : Coking wastewater causes severe environmental pollution because of its high concentration of organics and other dangerous chemicals, which makes it difficult to reuse by conventional technologies. In this article, we report an investigation of the electrochemical oxidation of coking wastewater at 298 K and 1 atm in the presence of ozone, where the reaction was assisted by potassium permanganate as the catalyst and kaolin as the carrier. The results showed that the refractory organics in wastewater can be effectively removed by this process, and a chemical oxygen demand (COD) removal efficiency of 92.5% was obtained in 80 min at pH 3. Operating parameters such as the current density, initial pH, and amount of catalyst were investigated. Catalyst lifetime was also tested, and the results showed that catalyst activity still remained even after the catalyst had been used three times. The impact of the treated wastewater on chlorophyll was also investigated, with a steady amount of chlorophyll indicating that the treated wastewater could be applied to irrigation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800826v [article] Electrochemical oxidation of refractory organics wastewater and chemical oxygen demand (COD) Removal under Extremely Mild Condition [texte imprimé] / Bo Wang, Auteur ; Xin Chang, Auteur ; Hongzhu Ma, Auteur . - 2008 . - p. 8478–8483. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8478–8483 Mots-clés : Wastewater causes Pollution Résumé : Coking wastewater causes severe environmental pollution because of its high concentration of organics and other dangerous chemicals, which makes it difficult to reuse by conventional technologies. In this article, we report an investigation of the electrochemical oxidation of coking wastewater at 298 K and 1 atm in the presence of ozone, where the reaction was assisted by potassium permanganate as the catalyst and kaolin as the carrier. The results showed that the refractory organics in wastewater can be effectively removed by this process, and a chemical oxygen demand (COD) removal efficiency of 92.5% was obtained in 80 min at pH 3. Operating parameters such as the current density, initial pH, and amount of catalyst were investigated. Catalyst lifetime was also tested, and the results showed that catalyst activity still remained even after the catalyst had been used three times. The impact of the treated wastewater on chlorophyll was also investigated, with a steady amount of chlorophyll indicating that the treated wastewater could be applied to irrigation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800826v

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Gas back-mixing in a two-dimensional baffled turbulent fluidized bed / Yongmin Zhang in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8484–8491 Titre : Gas back-mixing in a two-dimensional baffled turbulent fluidized bed Type de document : texte imprimé Auteurs : Yongmin Zhang, Auteur ; Chunxi Lu, Auteur ; John R. Grace, Auteur Année de publication : 2008 Article en page(s) : p. 8484–8491 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Turbulent fluidized Résumé : The effect of louver baffles on gas back-mixing was investigated in a large-scale two-dimensional fluidized bed of fluid catalytic cracking (FCC) particles with helium as tracer gas. The axial gas dispersion coefficient of the baffle-free fluidized bed first increased with increasing superficial gas velocity and then decreased after reaching a maximum near the onset of the turbulent flow regime. “Gulf streaming” of emulsion flow in the baffle-free bed determined the lateral profiles of tracer gas concentration. Solids back-mixing flux was greatly reduced by the addition of a layer of louver baffles, while solids mixing above the baffle layer was enhanced. The modified baffled fluidized bed with multilayer louver baffles not only provided a high efficiency of gas−solids contacting but also greatly suppressed the back-mixing of both gas and solids. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800906n [article] Gas back-mixing in a two-dimensional baffled turbulent fluidized bed [texte imprimé] / Yongmin Zhang, Auteur ; Chunxi Lu, Auteur ; John R. Grace, Auteur . - 2008 . - p. 8484–8491. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8484–8491 Mots-clés : Turbulent fluidized Résumé : The effect of louver baffles on gas back-mixing was investigated in a large-scale two-dimensional fluidized bed of fluid catalytic cracking (FCC) particles with helium as tracer gas. The axial gas dispersion coefficient of the baffle-free fluidized bed first increased with increasing superficial gas velocity and then decreased after reaching a maximum near the onset of the turbulent flow regime. “Gulf streaming” of emulsion flow in the baffle-free bed determined the lateral profiles of tracer gas concentration. Solids back-mixing flux was greatly reduced by the addition of a layer of louver baffles, while solids mixing above the baffle layer was enhanced. The modified baffled fluidized bed with multilayer louver baffles not only provided a high efficiency of gas−solids contacting but also greatly suppressed the back-mixing of both gas and solids. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800906n

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Research note previous article next article table of contents experimental data and predictions of dissociation conditions for methane ethane propane, and carbon dioxide simple hydrates in the presence of glycerol aqueous solutions / Amir H. Mohammadi in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8492–8495 Titre : Research note previous article next article table of contents experimental data and predictions of dissociation conditions for methane ethane propane, and carbon dioxide simple hydrates in the presence of glycerol aqueous solutions Type de document : texte imprimé Auteurs : Amir H. Mohammadi, Auteur ; Ilyas Kraouti, Auteur ; Dominique Richon, Auteur Année de publication : 2008 Article en page(s) : p. 8492–8495 Note générale : Chemical engineering Langues : Anglais (eng) Résumé : Experimental dissociation data for methane, ethane, and carbon dioxide simple hydrates in the presence of 0.1 and 0.4 mass fraction glycerol aqueous solutions and dissociation data for propane simple hydrates in the presence of 0.1 mass fraction glycerol aqueous solution are reported in this communication. The experimental data were generated using a reliable isochoric pressure-search method. The new experimental dissociation data for carbon dioxide simple hydrates in the presence of 0.1 mass fraction glycerol aqueous solution are compared with the experimental data reported in the literature and the agreements are generally found acceptable. All the experimental data are finally compared with the predictions of a general correlation and acceptable agreements between the experimental and predicted data are generally observed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801018e [article] Research note previous article next article table of contents experimental data and predictions of dissociation conditions for methane ethane propane, and carbon dioxide simple hydrates in the presence of glycerol aqueous solutions [texte imprimé] / Amir H. Mohammadi, Auteur ; Ilyas Kraouti, Auteur ; Dominique Richon, Auteur . - 2008 . - p. 8492–8495. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8492–8495 Résumé : Experimental dissociation data for methane, ethane, and carbon dioxide simple hydrates in the presence of 0.1 and 0.4 mass fraction glycerol aqueous solutions and dissociation data for propane simple hydrates in the presence of 0.1 mass fraction glycerol aqueous solution are reported in this communication. The experimental data were generated using a reliable isochoric pressure-search method. The new experimental dissociation data for carbon dioxide simple hydrates in the presence of 0.1 mass fraction glycerol aqueous solution are compared with the experimental data reported in the literature and the agreements are generally found acceptable. All the experimental data are finally compared with the predictions of a general correlation and acceptable agreements between the experimental and predicted data are generally observed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801018e

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Room-temperature ionic liquid−amine solutions: tunable solvents for efficient and reversible capture of cO2 / Dean Camper in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8496–8498 Titre : Room-temperature ionic liquid−amine solutions: tunable solvents for efficient and reversible capture of cO2 Type de document : texte imprimé Auteurs : Dean Camper, Auteur ; Jason E. Bara, Auteur ; Douglas L. Gin, Auteur Année de publication : 2008 Article en page(s) : p. 8496–8498 Langues : Anglais (eng) Résumé : Solutions of room-temperature ionic liquids (RTILs) and commercially available amines were found to be effective for the capture of CO2 as carbamate salts. RTIL solutions containing 50 mol % (16% v/v) monoethanolamine (MEA) are capable of rapid and reversible capture of 1 mol of CO2 per 2 moles MEA to give an insoluble MEA−carbamate precipitate that helps to drive the capture reaction (as opposed to aqueous amine systems). Diethanolamine (DEA) can also be used in the same manner for CO2 capture in RTILs containing a pendant hydroxyl group. The captured CO2 in the resulting RTIL−carbamate salt mixtures can be readily released by either heating and/or subjecting them to reduced pressure. Using this unprecedented and industrially attractive mixing approach, the desirable properties of RTILs (i.e., nonvolatility, enhanced CO2 solubility, lower heat capacities) can be combined with the performance of amines for CO2 capture without the use of specially designed, functionalized “task-specific” ionic liquids. By mixing RTILs with commercial amines, reactive solvents with a wide range of amine loading levels can be tailored to capture CO2 in a variety of conditions and processes. These RTIL−amine solutions behave similarly to their water-based counterparts but may offer many advantages, including increased energy efficiency, compared to current aqueous amine technologies. [article] Room-temperature ionic liquid−amine solutions: tunable solvents for efficient and reversible capture of cO2 [texte imprimé] / Dean Camper, Auteur ; Jason E. Bara, Auteur ; Douglas L. Gin, Auteur . - 2008 . - p. 8496–8498. Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8496–8498 Résumé : Solutions of room-temperature ionic liquids (RTILs) and commercially available amines were found to be effective for the capture of CO2 as carbamate salts. RTIL solutions containing 50 mol % (16% v/v) monoethanolamine (MEA) are capable of rapid and reversible capture of 1 mol of CO2 per 2 moles MEA to give an insoluble MEA−carbamate precipitate that helps to drive the capture reaction (as opposed to aqueous amine systems). Diethanolamine (DEA) can also be used in the same manner for CO2 capture in RTILs containing a pendant hydroxyl group. The captured CO2 in the resulting RTIL−carbamate salt mixtures can be readily released by either heating and/or subjecting them to reduced pressure. Using this unprecedented and industrially attractive mixing approach, the desirable properties of RTILs (i.e., nonvolatility, enhanced CO2 solubility, lower heat capacities) can be combined with the performance of amines for CO2 capture without the use of specially designed, functionalized “task-specific” ionic liquids. By mixing RTILs with commercial amines, reactive solvents with a wide range of amine loading levels can be tailored to capture CO2 in a variety of conditions and processes. These RTIL−amine solutions behave similarly to their water-based counterparts but may offer many advantages, including increased energy efficiency, compared to current aqueous amine technologies.

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Estimating Sulfur Content of Hydrog Sulfide at elevated temperatures and Pressures using an Atificial Neural Network Algorithm / Amir H. Mohammadi in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8499–8504 Titre : Estimating Sulfur Content of Hydrog Sulfide at elevated temperatures and Pressures using an Atificial Neural Network Algorithm Type de document : texte imprimé Auteurs : Amir H. Mohammadi, Auteur ; Dominique Richon, Auteur Année de publication : 2008 Article en page(s) : p. 8499–8504 Note générale : chemical engineering Langues : Anglais (eng) Résumé : In this communication, we report an artificial neural network algorithm for estimating sulfur content of hydrogen sulfide at elevated temperatures and pressures. This model eliminates any need for characterization parameters, due to the tendency of sulfurs to react, required in thermodynamic models. To develop this algorithm, reliable experimental data reported in the literature on sulfur content of hydrogen sulfide are used. The developed model is then used to predict independent experimental data (not used in developing the model). It is shown that artificial neural network algorithm can be used as an efficient tool to estimate sulfur content of hydrogen sulfide. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8004463 [article] Estimating Sulfur Content of Hydrog Sulfide at elevated temperatures and Pressures using an Atificial Neural Network Algorithm [texte imprimé] / Amir H. Mohammadi, Auteur ; Dominique Richon, Auteur . - 2008 . - p. 8499–8504. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8499–8504 Résumé : In this communication, we report an artificial neural network algorithm for estimating sulfur content of hydrogen sulfide at elevated temperatures and pressures. This model eliminates any need for characterization parameters, due to the tendency of sulfurs to react, required in thermodynamic models. To develop this algorithm, reliable experimental data reported in the literature on sulfur content of hydrogen sulfide are used. The developed model is then used to predict independent experimental data (not used in developing the model). It is shown that artificial neural network algorithm can be used as an efficient tool to estimate sulfur content of hydrogen sulfide. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8004463

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Cfd simulation of bubble column reactor using population balance / Kalekudithi Ekambara in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8505–8516 Titre : Cfd simulation of bubble column reactor using population balance Type de document : texte imprimé Auteurs : Kalekudithi Ekambara, Auteur ; Kumar Nandakuma, Auteur ; Jyeshtharaj B. Joshi, Auteur Année de publication : 2008 Article en page(s) : p. 8505–8516 Langues : Anglais (eng) Résumé : In this paper, we have presented a comprehensive analysis of the development of flow pattern in a bubble column reactor by the introduction of a population balance equation combined with the three-dimensional two-fluid model (Reynolds stress model). The multiple size group (MUSIG) model has been used to account for the nonuniform bubble size distribution in a gas−liquid mixture. The coalescence and breakage effects of the gas bubbles are modeled according to the coalescence by the random collision driven by turbulence and wake entrainment while for bubble breakage by the impact of turbulent eddies. Local radial distributions of the gas hold-up, Sauter mean bubble diameter, axial liquid velocity, turbulent kinetic energy, turbulent energy dissipation rate, and Reynolds stresses for superficial gas velocity of 20 mm/s are compared against experimental data in a bubble column reactor. The development of flow pattern were examined at six axial locations H/D = 0.2, 1.4, 2.6, 3.9, 5.0, and 6.2. Good quantitative agreement with the experimental data is obtained with three different models (i.e., k−ε, RSM with constant bubble size, and RSM with population balance). The model prediction shows better agreement with the experimental data with population balance than constant bubble diameter predictions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071393e [article] Cfd simulation of bubble column reactor using population balance [texte imprimé] / Kalekudithi Ekambara, Auteur ; Kumar Nandakuma, Auteur ; Jyeshtharaj B. Joshi, Auteur . - 2008 . - p. 8505–8516. Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8505–8516 Résumé : In this paper, we have presented a comprehensive analysis of the development of flow pattern in a bubble column reactor by the introduction of a population balance equation combined with the three-dimensional two-fluid model (Reynolds stress model). The multiple size group (MUSIG) model has been used to account for the nonuniform bubble size distribution in a gas−liquid mixture. The coalescence and breakage effects of the gas bubbles are modeled according to the coalescence by the random collision driven by turbulence and wake entrainment while for bubble breakage by the impact of turbulent eddies. Local radial distributions of the gas hold-up, Sauter mean bubble diameter, axial liquid velocity, turbulent kinetic energy, turbulent energy dissipation rate, and Reynolds stresses for superficial gas velocity of 20 mm/s are compared against experimental data in a bubble column reactor. The development of flow pattern were examined at six axial locations H/D = 0.2, 1.4, 2.6, 3.9, 5.0, and 6.2. Good quantitative agreement with the experimental data is obtained with three different models (i.e., k−ε, RSM with constant bubble size, and RSM with population balance). The model prediction shows better agreement with the experimental data with population balance than constant bubble diameter predictions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071393e

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