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Vol. 49 N° 20 - Octobre 2010 [texte imprimé] . - 2011 . - p. 9565-10152 : ill. ; 28 cm. Chemical engineering Langues : Français (fre)
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Ajouter le résultat dans votre panierCharge carrier transfer / Jacek Tyczkowski in Industrial & engineering chemistry research, Vol. 49 N° 20 (Octobre 2010)
Titre : Charge carrier transfer : A neglected process in chemical engineering Type de document : texte imprimé Auteurs : Jacek Tyczkowski, Auteur Année de publication : 2011 Article en page(s) : pp. 9565–9579 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Carrier transfer Résumé : This paper presents the discussion that charge carrier transfer should be treated by modern chemical engineering on equal terms with other transfer processes such as mass, heat, and momentum transfer. In an age when chemical engineering is entering the field of electronics, electrostatics, and electrochemistry, more and more often involving examination down to the molecular level, it is impossible to describe much phenomena without taking into consideration the charge carrier transfer. The discussion, the main goal of which is to familiarize chemical engineers with the fundamentals of charge transfer processes, is focused on covalent amorphous materials that are particularly interesting for advanced technologies. The paper presents a review of the generation mechanisms (band-to-band generation, Poole−Frenkel mechanism, charge carrier injection from contacts, photogeneration) and transport mechanisms (band transport, hopping transport) governing the charge carrier transfer on the molecular level. The problems with determining the dominant mechanisms for a given material are also discussed. Finally, specific examples of the use of the charge carrier transfer in chemical engineering are presented. The main attention is focused on electrochemical devices, electrocatalysis, photocatalysis, charging phenomena, and single-molecule engineering. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101069w
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9565–9579[article] Charge carrier transfer : A neglected process in chemical engineering [texte imprimé] / Jacek Tyczkowski, Auteur . - 2011 . - pp. 9565–9579.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9565–9579
Mots-clés : Carrier transfer Résumé : This paper presents the discussion that charge carrier transfer should be treated by modern chemical engineering on equal terms with other transfer processes such as mass, heat, and momentum transfer. In an age when chemical engineering is entering the field of electronics, electrostatics, and electrochemistry, more and more often involving examination down to the molecular level, it is impossible to describe much phenomena without taking into consideration the charge carrier transfer. The discussion, the main goal of which is to familiarize chemical engineers with the fundamentals of charge transfer processes, is focused on covalent amorphous materials that are particularly interesting for advanced technologies. The paper presents a review of the generation mechanisms (band-to-band generation, Poole−Frenkel mechanism, charge carrier injection from contacts, photogeneration) and transport mechanisms (band transport, hopping transport) governing the charge carrier transfer on the molecular level. The problems with determining the dominant mechanisms for a given material are also discussed. Finally, specific examples of the use of the charge carrier transfer in chemical engineering are presented. The main attention is focused on electrochemical devices, electrocatalysis, photocatalysis, charging phenomena, and single-molecule engineering. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101069w Exemplaires
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Titre : Thermophysical properties of pure ionic liquids : Review of present situation Type de document : texte imprimé Auteurs : Santiago Aparicio, Auteur ; Mert Atilhan, Auteur ; Ferdi Karadas, Auteur Année de publication : 2011 Article en page(s) : pp. 9580–9595 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ionic liquids Résumé : The large collection of thermophysical properties data for liquids available in the open literature is analyzed, describing its importance for industrial purposes. Although there has been a boom of thermophysical properties measurements for these fluids in the past decade, the reported analysis shows that studies have been centered on a limited number of fluids, whereas data collection for the new family ionic liquids is lacking. Measurements have been performed for limited temperature ranges, and pressure effects on the properties are extremely scarce in the literature; remarkable differences among data from different literature sources are reported. The need of sample purity quantification is analyzed together with the strong effect of these impurities on thermophysical properties. Available predictive models for the studied properties are analyzed together with the quality of their predictions. The main conclusion of this review is to point out the need of further systematic thermophysical studies, including for new environmentally friendly ionic liquids, carried out with interlaboratory comparisons, which allow the development of reference data sets. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101441s
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9580–9595[article] Thermophysical properties of pure ionic liquids : Review of present situation [texte imprimé] / Santiago Aparicio, Auteur ; Mert Atilhan, Auteur ; Ferdi Karadas, Auteur . - 2011 . - pp. 9580–9595.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9580–9595
Mots-clés : Ionic liquids Résumé : The large collection of thermophysical properties data for liquids available in the open literature is analyzed, describing its importance for industrial purposes. Although there has been a boom of thermophysical properties measurements for these fluids in the past decade, the reported analysis shows that studies have been centered on a limited number of fluids, whereas data collection for the new family ionic liquids is lacking. Measurements have been performed for limited temperature ranges, and pressure effects on the properties are extremely scarce in the literature; remarkable differences among data from different literature sources are reported. The need of sample purity quantification is analyzed together with the strong effect of these impurities on thermophysical properties. Available predictive models for the studied properties are analyzed together with the quality of their predictions. The main conclusion of this review is to point out the need of further systematic thermophysical studies, including for new environmentally friendly ionic liquids, carried out with interlaboratory comparisons, which allow the development of reference data sets. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101441s Exemplaires
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Titre : Deliquescence in the hydrolysis of sodium borohydride by water vapor Type de document : texte imprimé Auteurs : Amy M. Beaird, Auteur ; Thomas A. Davis, Auteur ; Michael A. Matthews, Auteur Année de publication : 2011 Article en page(s) : pp. 9596–9599 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydrolysis Water Vapor Résumé : The interaction between sodium borohydride (NaBH4) and water vapor leading to hydrolysis and hydrogen generation has been investigated by a visual technique. In situ video monitoring confirms that reaction is preceded by deliquescence of NaBH4 upon exposure to water vapor, forming a viscous liquid solution that releases hydrogen. A regime of temperature and relative humidity under which the deliquescence is favorable has been determined. A relative humidity threshold exists below which NaBH4 powder does not absorb water vapor into the bulk to form a solution and thereby does not undergo reaction to form hydrogen. The deliquescence behavior of NaBH4 in water vapor provides an alternative reaction pathway that has potential to improve hydrogen storage density by reducing excess water and other additives. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100244v
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9596–9599[article] Deliquescence in the hydrolysis of sodium borohydride by water vapor [texte imprimé] / Amy M. Beaird, Auteur ; Thomas A. Davis, Auteur ; Michael A. Matthews, Auteur . - 2011 . - pp. 9596–9599.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9596–9599
Mots-clés : Hydrolysis Water Vapor Résumé : The interaction between sodium borohydride (NaBH4) and water vapor leading to hydrolysis and hydrogen generation has been investigated by a visual technique. In situ video monitoring confirms that reaction is preceded by deliquescence of NaBH4 upon exposure to water vapor, forming a viscous liquid solution that releases hydrogen. A regime of temperature and relative humidity under which the deliquescence is favorable has been determined. A relative humidity threshold exists below which NaBH4 powder does not absorb water vapor into the bulk to form a solution and thereby does not undergo reaction to form hydrogen. The deliquescence behavior of NaBH4 in water vapor provides an alternative reaction pathway that has potential to improve hydrogen storage density by reducing excess water and other additives. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100244v Exemplaires
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Titre : Degradation of the insulating system of power transformers by copper sulfide deposition : Influence of oil oxidation and presence of metal passivator Type de document : texte imprimé Auteurs : Jelena M. Lukic, Auteur ; Srdjan B. Milosavljevic, Auteur ; Aleksandar M. Orlovic, Auteur Année de publication : 2011 Article en page(s) : pp. 9600–9608 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Oxidation Résumé : Deposition of conductive copper sulfide on paper insulation of power transformers was recognized as a serious risk that can result in equipment failure. The aim of this study was to investigate the influence of mineral insulating oil oxidation and the presence of metal passivator on copper sulfide (Cu2S) deposition. Oil oxidation was found to increase deposition of Cu2S on the insulating paper, as confirmed by IEC 61125 B and IEC 62535 tests. The presence of oxygen resulted in an increase of copper dissolution in the oil and facilitated progressive copper sulfide deposition on the insulating paper, as confirmed by ICP, AAS, and EDX measurements. The effectiveness of aminomethyl substituted toluylbenzotriazole (TTA) metal passivator in suppressing copper sulfide formation and deposition was studied using modified IEC 62535 test. The protective role of TTA bonded to the copper plate surface and absorbed in the insulating paper was observed in tests at 140 and 150 °C, even for highly oxidized oils. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325777
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9600–9608[article] Degradation of the insulating system of power transformers by copper sulfide deposition : Influence of oil oxidation and presence of metal passivator [texte imprimé] / Jelena M. Lukic, Auteur ; Srdjan B. Milosavljevic, Auteur ; Aleksandar M. Orlovic, Auteur . - 2011 . - pp. 9600–9608.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9600–9608
Mots-clés : Oxidation Résumé : Deposition of conductive copper sulfide on paper insulation of power transformers was recognized as a serious risk that can result in equipment failure. The aim of this study was to investigate the influence of mineral insulating oil oxidation and the presence of metal passivator on copper sulfide (Cu2S) deposition. Oil oxidation was found to increase deposition of Cu2S on the insulating paper, as confirmed by IEC 61125 B and IEC 62535 tests. The presence of oxygen resulted in an increase of copper dissolution in the oil and facilitated progressive copper sulfide deposition on the insulating paper, as confirmed by ICP, AAS, and EDX measurements. The effectiveness of aminomethyl substituted toluylbenzotriazole (TTA) metal passivator in suppressing copper sulfide formation and deposition was studied using modified IEC 62535 test. The protective role of TTA bonded to the copper plate surface and absorbed in the insulating paper was observed in tests at 140 and 150 °C, even for highly oxidized oils. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325777 Exemplaires
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Titre : Synthesis of dimethyl carbonate from methanol and carbon dioxide : Circumventing thermodynamic limitations Type de document : texte imprimé Auteurs : Valerie Eta, Auteur ; Paivi Maki-Arvela, Auteur ; Anne-Riikka Leino, Auteur Année de publication : 2011 Article en page(s) : pp. 9609–9617 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Carbon dioxide Résumé : The synthesis of dimethyl carbonate from methanol and CO2 catalyzed by ZrO2 doped with KCl was investigated using chemical traps for water to circumvent thermodynamic limitations. The reaction, promoted by magnesium, occurred via the formation of carbonated magnesium methoxide (CMM) which adsorbed on the surface of ZrO2. The surface migration of the oxygen atom of ZrO2 to the surface methoxy groups of CMM resulted in the formation of dimethyl carbonate. The resulting MgO then reacted with methanol forming water and regenerating magnesium methoxide. The water formed reacted with the dehydrating agent, thus shifting the equilibrium toward a higher yield of DMC. The yield of 7.2 mol % DMC and 13.6 mol % conversion of methanol was obtained when methanol reacted with CO2 at 150 °C and 9.5 MPa for 8 h. The plausible reaction pathway is described. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325778
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9609–9617[article] Synthesis of dimethyl carbonate from methanol and carbon dioxide : Circumventing thermodynamic limitations [texte imprimé] / Valerie Eta, Auteur ; Paivi Maki-Arvela, Auteur ; Anne-Riikka Leino, Auteur . - 2011 . - pp. 9609–9617.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9609–9617
Mots-clés : Carbon dioxide Résumé : The synthesis of dimethyl carbonate from methanol and CO2 catalyzed by ZrO2 doped with KCl was investigated using chemical traps for water to circumvent thermodynamic limitations. The reaction, promoted by magnesium, occurred via the formation of carbonated magnesium methoxide (CMM) which adsorbed on the surface of ZrO2. The surface migration of the oxygen atom of ZrO2 to the surface methoxy groups of CMM resulted in the formation of dimethyl carbonate. The resulting MgO then reacted with methanol forming water and regenerating magnesium methoxide. The water formed reacted with the dehydrating agent, thus shifting the equilibrium toward a higher yield of DMC. The yield of 7.2 mol % DMC and 13.6 mol % conversion of methanol was obtained when methanol reacted with CO2 at 150 °C and 9.5 MPa for 8 h. The plausible reaction pathway is described. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325778 Exemplaires
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Titre : Research on the gelation performance of low toxic PEI cross - linking PHPAM gel systems as water shutoff agents in low temperature reservoirs Type de document : texte imprimé Auteurs : Hu Jia, Auteur ; Wan-Fen Pu, Auteur ; Jin-Zhou Zhao, Auteur Année de publication : 2011 Article en page(s) : pp. 9618–9624 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Gelation performance Résumé : Using gel as the water shutoff agent has been widely reported in the aspect of enhanced oil recovery (EOR) of the development of mature oil fields. Cross-linkers such as chromium(III) acetate and phenol−formaldehyde are commonly used, but they are toxic. Today, use of low toxic polyethyleneimine (PEI) cross-linking a copolymer of acrylamide and tert-butyl acrylate (PAtBA) as the water shutoff gel is reported more but is mainly focused on its theoretical research and applications in high temperature reservoirs. Because of the defects of the chromium(III) acetate and phenol−formaldehyde cross-linkers, the gelation performance of PEI/partially hydrolyzed polyacrylamide (PHPAM) gel systems at low temperature (40 °C) is discussed in this paper. The results show that the gelation time and strength of the PEI/PHPAM gel system can be perfectly controlled by adjusting the PHPAM concentration, the molecular weight, the PEI concentration, and the total dissolved solids. The polymer concentration and molecular weight can affect not only the gelation time and the gel strength but also its stability. Among them the polymer concentration is the most important factor that affects the gel stability. For the low temperature reservoirs, the most common used chromium(III) acetate/PHPAM gel system has only around 5 h of gelation time at 40 °C to get a high gel strength. However, the PEI/PHPAM gel system can achieve a much longer gelation time. Polymer gels formulated with a combination of 1.5 wt % PHPAM and added 0.3−0.8 wt % PEI provide a gelation time between 15 h and 9 days, and the maximum gel strength could reach code I. This study suggests that the low toxic PEI/PHPAM gel system can be used in low temperature reservoirs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100888q
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9618–9624[article] Research on the gelation performance of low toxic PEI cross - linking PHPAM gel systems as water shutoff agents in low temperature reservoirs [texte imprimé] / Hu Jia, Auteur ; Wan-Fen Pu, Auteur ; Jin-Zhou Zhao, Auteur . - 2011 . - pp. 9618–9624.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9618–9624
Mots-clés : Gelation performance Résumé : Using gel as the water shutoff agent has been widely reported in the aspect of enhanced oil recovery (EOR) of the development of mature oil fields. Cross-linkers such as chromium(III) acetate and phenol−formaldehyde are commonly used, but they are toxic. Today, use of low toxic polyethyleneimine (PEI) cross-linking a copolymer of acrylamide and tert-butyl acrylate (PAtBA) as the water shutoff gel is reported more but is mainly focused on its theoretical research and applications in high temperature reservoirs. Because of the defects of the chromium(III) acetate and phenol−formaldehyde cross-linkers, the gelation performance of PEI/partially hydrolyzed polyacrylamide (PHPAM) gel systems at low temperature (40 °C) is discussed in this paper. The results show that the gelation time and strength of the PEI/PHPAM gel system can be perfectly controlled by adjusting the PHPAM concentration, the molecular weight, the PEI concentration, and the total dissolved solids. The polymer concentration and molecular weight can affect not only the gelation time and the gel strength but also its stability. Among them the polymer concentration is the most important factor that affects the gel stability. For the low temperature reservoirs, the most common used chromium(III) acetate/PHPAM gel system has only around 5 h of gelation time at 40 °C to get a high gel strength. However, the PEI/PHPAM gel system can achieve a much longer gelation time. Polymer gels formulated with a combination of 1.5 wt % PHPAM and added 0.3−0.8 wt % PEI provide a gelation time between 15 h and 9 days, and the maximum gel strength could reach code I. This study suggests that the low toxic PEI/PHPAM gel system can be used in low temperature reservoirs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100888q Exemplaires
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Titre : Ion exchange equilibrium carbonate treatment for anticorrosion in open recirculating cooling water system Type de document : texte imprimé Auteurs : Chunsong Ye, Auteur ; Jiuyang Lin, Auteur ; Hong Yang, Auteur Année de publication : 2011 Article en page(s) : pp. 9625–9630 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ion exchange Résumé : The study presents the results of ion exchange equilibrium carbonate treatment to prevent brass corrosion in open recirculating cooling water system. The treatment process can remove the hardness and aggressive anions, transform all of the ions into sodium bicarbonate and sodium carbonate, and form the open carbonate equilibrium system. In the static corrosion test, brass has the lowest corrosion rate of 1.36 × 10−3 mm/year in the open carbonate equilibrium system with total alkalinity of 6.00 × 10−3 mol/L. And during the 8-day dynamic simulation experiment of ion exchange equilibrium carbonate treatment, the recirculating water with total alkalinity of 6.00 × 10−3 mol/L that achieves open carbonate equilibrium state has the excellent buffer action when pH value of makeup water ranges from 5.94 to 11.26, and prevent brass after passivation with hydrogen peroxide (H2O2) solution from corrosion. So ion exchange equilibrium carbonate treatment is an effective and environmentally friendly method to treat the recirculating cooling water without corrosion inhibitor addition. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100913d
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9625–9630[article] Ion exchange equilibrium carbonate treatment for anticorrosion in open recirculating cooling water system [texte imprimé] / Chunsong Ye, Auteur ; Jiuyang Lin, Auteur ; Hong Yang, Auteur . - 2011 . - pp. 9625–9630.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9625–9630
Mots-clés : Ion exchange Résumé : The study presents the results of ion exchange equilibrium carbonate treatment to prevent brass corrosion in open recirculating cooling water system. The treatment process can remove the hardness and aggressive anions, transform all of the ions into sodium bicarbonate and sodium carbonate, and form the open carbonate equilibrium system. In the static corrosion test, brass has the lowest corrosion rate of 1.36 × 10−3 mm/year in the open carbonate equilibrium system with total alkalinity of 6.00 × 10−3 mol/L. And during the 8-day dynamic simulation experiment of ion exchange equilibrium carbonate treatment, the recirculating water with total alkalinity of 6.00 × 10−3 mol/L that achieves open carbonate equilibrium state has the excellent buffer action when pH value of makeup water ranges from 5.94 to 11.26, and prevent brass after passivation with hydrogen peroxide (H2O2) solution from corrosion. So ion exchange equilibrium carbonate treatment is an effective and environmentally friendly method to treat the recirculating cooling water without corrosion inhibitor addition. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100913d Exemplaires
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Titre : Conductive - diamond electrochemical oxidation of surfactant - aided soil - washing effluents Type de document : texte imprimé Auteurs : Cristina Saez, Auteur ; Ruben Lopez-Vizcaino, Auteur ; Pablo Canizares, Auteur Année de publication : 2011 Article en page(s) : pp. 9631–9635 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Electrochemical Oxidation Résumé : Washing of soils polluted with polycyclic aromatic hydrocarbons (PAHs) using surfactant is a widely used technique. Once the pollutant is transferred to the washing solution, the polluted wastewater has to be treated. In this work, the feasibility of conductive-diamond electrochemical oxidation (CDEO) to treat wastewater polluted with phenanthrene (selected as model PAHs) and three different surfactants (anionic, cationic, and nonionic), which were tested as the washing solution, has been studied. The results show that CDEO enables a significant reduction in the organic load of the wastes regardless of the surfactant present. However, the process efficiency is largely influenced by the type of surfactant employed. Thus, aliphatic linear-chain species seem to lead to the formation of oxidation-refractory compounds, whereas molecules with an aromatic structure favor the formation of insoluble species. The observed changes in pH and conductivity seem to confirm this assumption. In contrast, dimensionally stable anode technology is ineffective in the treatment of these effluents. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101224t
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9631–9635[article] Conductive - diamond electrochemical oxidation of surfactant - aided soil - washing effluents [texte imprimé] / Cristina Saez, Auteur ; Ruben Lopez-Vizcaino, Auteur ; Pablo Canizares, Auteur . - 2011 . - pp. 9631–9635.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9631–9635
Mots-clés : Electrochemical Oxidation Résumé : Washing of soils polluted with polycyclic aromatic hydrocarbons (PAHs) using surfactant is a widely used technique. Once the pollutant is transferred to the washing solution, the polluted wastewater has to be treated. In this work, the feasibility of conductive-diamond electrochemical oxidation (CDEO) to treat wastewater polluted with phenanthrene (selected as model PAHs) and three different surfactants (anionic, cationic, and nonionic), which were tested as the washing solution, has been studied. The results show that CDEO enables a significant reduction in the organic load of the wastes regardless of the surfactant present. However, the process efficiency is largely influenced by the type of surfactant employed. Thus, aliphatic linear-chain species seem to lead to the formation of oxidation-refractory compounds, whereas molecules with an aromatic structure favor the formation of insoluble species. The observed changes in pH and conductivity seem to confirm this assumption. In contrast, dimensionally stable anode technology is ineffective in the treatment of these effluents. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101224t Exemplaires
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Titre : Microwave assisted synthesis of nanostructured titanium dioxide with high photocatalytic activity Type de document : texte imprimé Auteurs : Anirudha Jena, Auteur ; R. Vinu, Auteur ; S. A. Shivashankar, Auteur Année de publication : 2011 Article en page(s) : pp. 9636–9643 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Microwave Titanium Dioxide Résumé : TiO2 (anatase) was synthesized using a microwave-irradiation-assisted chemical method. The reaction conditions were varied to obtain unique nanostructures of TiO2 comprising nanometric spheres giving the materials a very porous morphology. The oxide was characterized by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). The specific surface area and porosity were quantified by the BET method, and the degradation of dyes was carried out using these materials. The photocatalytic activity of the nanometric TiO2 was significantly higher than that of commercially available TiO2 (Degussa P25) for the degradation of the dyes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101226b
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9636–9643[article] Microwave assisted synthesis of nanostructured titanium dioxide with high photocatalytic activity [texte imprimé] / Anirudha Jena, Auteur ; R. Vinu, Auteur ; S. A. Shivashankar, Auteur . - 2011 . - pp. 9636–9643.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9636–9643
Mots-clés : Microwave Titanium Dioxide Résumé : TiO2 (anatase) was synthesized using a microwave-irradiation-assisted chemical method. The reaction conditions were varied to obtain unique nanostructures of TiO2 comprising nanometric spheres giving the materials a very porous morphology. The oxide was characterized by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). The specific surface area and porosity were quantified by the BET method, and the degradation of dyes was carried out using these materials. The photocatalytic activity of the nanometric TiO2 was significantly higher than that of commercially available TiO2 (Degussa P25) for the degradation of the dyes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101226b Exemplaires
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Titre : Evaluation of waterborne coating for controlled - release fertilizer using wurster fluidized bed Type de document : texte imprimé Auteurs : Zhao Cong, Auteur ; Shen Yazhen, Auteur ; Du Changwen, Auteur Année de publication : 2011 Article en page(s) : pp. 9644–9647 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Fluidized bed Fluidization Fertilization Fertilizers Résumé : Coating through polymer film to control nutrient release can reduce the nutrient losses and minimize environmental contamination. In this research, the waterborne acrylate latex and additive (cross-linker aziridine) were used to develop coated controlled-release fertilizers by Wurster-type fluidized bed, and the influences of different cross-linker percentage on the coating properties and the nutrient-release profiles were investigated. The results indicated that the waterborne coating coupled with the 2 wt % of cross-linker could effectively decrease the swelling capacity of the membrane to 5.54 ± 0.32% while obtaining a suitable Tg (6.13 °C); the cumulative nutrient-release percentage was significantly improved to around 40% in 9 days at 40 °C. This organic solvent-free coating provided a promising option for the development of coated controlled-release fertilizer. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325783
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9644–9647[article] Evaluation of waterborne coating for controlled - release fertilizer using wurster fluidized bed [texte imprimé] / Zhao Cong, Auteur ; Shen Yazhen, Auteur ; Du Changwen, Auteur . - 2011 . - pp. 9644–9647.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9644–9647
Mots-clés : Fluidized bed Fluidization Fertilization Fertilizers Résumé : Coating through polymer film to control nutrient release can reduce the nutrient losses and minimize environmental contamination. In this research, the waterborne acrylate latex and additive (cross-linker aziridine) were used to develop coated controlled-release fertilizers by Wurster-type fluidized bed, and the influences of different cross-linker percentage on the coating properties and the nutrient-release profiles were investigated. The results indicated that the waterborne coating coupled with the 2 wt % of cross-linker could effectively decrease the swelling capacity of the membrane to 5.54 ± 0.32% while obtaining a suitable Tg (6.13 °C); the cumulative nutrient-release percentage was significantly improved to around 40% in 9 days at 40 °C. This organic solvent-free coating provided a promising option for the development of coated controlled-release fertilizer. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325783 Exemplaires
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Titre : Retarding effect of aromatic solvents on cobalt (II) - based catalyst system during synthesis of high cis - 1,4 - polybutadiene Type de document : texte imprimé Auteurs : Archana Singh, Auteur ; Siddharth Modi, Auteur ; N. Subrahmanyam, Auteur Année de publication : 2011 Article en page(s) : pp. 9648–9654 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Aromatic solvents Catalyst Résumé : The present study discloses the influence of aliphatic (cyclohexane) and aromatic solvents with different π-electron densities viz. toluene, o-xylene, ethylbenzene (EB), and p-diethylbenzene (PDEB) on the cobalt-catalyzed high cis-polymerization of 1,3-butadiene. Comparative study in cyclohexane and toluene has been conducted in view to understand the effect of solvent on catalyst reactivity, molecular weight of the polymer, and polymerization kinetics. At given reaction conditions conversion is highest (68%) in cyclohexane, followed by toluene (27%) and EB (8%). Respective polymerization rate constants are found to be 0.0170, 0.0020, and 0.0008 min−1. Higher viscosity average molecular weight (M) of polymer observed in toluene (M = 4.68 × 105) compared to that in cyclohexane (M = 2.37 × 105) indicates that the presence of lower number of active sites leads to higher molecular weight. Cyclohexane shows activity at a lower water:alkylaluminum ratio than does toluene; as the π-electron of toluene reduces the Lewis acidity of hydrolyzed diethylaluminum chloride (DEAC) more than cyclohexane, where influence of π-electron is absent. The effect of different solvents has also been demonstrated by respective shifting of wavelength (λ) of solvent π → π*, cobalt 4A2 → 4T1(P), as well as 4T1 g (F) → 4T1 g (P) and activated butadienyl π(HOMO) → π*(LUMO) transitions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101324d
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9648–9654[article] Retarding effect of aromatic solvents on cobalt (II) - based catalyst system during synthesis of high cis - 1,4 - polybutadiene [texte imprimé] / Archana Singh, Auteur ; Siddharth Modi, Auteur ; N. Subrahmanyam, Auteur . - 2011 . - pp. 9648–9654.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9648–9654
Mots-clés : Aromatic solvents Catalyst Résumé : The present study discloses the influence of aliphatic (cyclohexane) and aromatic solvents with different π-electron densities viz. toluene, o-xylene, ethylbenzene (EB), and p-diethylbenzene (PDEB) on the cobalt-catalyzed high cis-polymerization of 1,3-butadiene. Comparative study in cyclohexane and toluene has been conducted in view to understand the effect of solvent on catalyst reactivity, molecular weight of the polymer, and polymerization kinetics. At given reaction conditions conversion is highest (68%) in cyclohexane, followed by toluene (27%) and EB (8%). Respective polymerization rate constants are found to be 0.0170, 0.0020, and 0.0008 min−1. Higher viscosity average molecular weight (M) of polymer observed in toluene (M = 4.68 × 105) compared to that in cyclohexane (M = 2.37 × 105) indicates that the presence of lower number of active sites leads to higher molecular weight. Cyclohexane shows activity at a lower water:alkylaluminum ratio than does toluene; as the π-electron of toluene reduces the Lewis acidity of hydrolyzed diethylaluminum chloride (DEAC) more than cyclohexane, where influence of π-electron is absent. The effect of different solvents has also been demonstrated by respective shifting of wavelength (λ) of solvent π → π*, cobalt 4A2 → 4T1(P), as well as 4T1 g (F) → 4T1 g (P) and activated butadienyl π(HOMO) → π*(LUMO) transitions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101324d Exemplaires
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Titre : Poly (glycidyl methacrylate) - polystyrene diblocks copolymer grafted nanocomposite microspheres from surface - initiated atom transfer radical polymerization for lipase immobilization : Application in flavor ester synthesis Type de document : texte imprimé Auteurs : Bunyamin Karagoz, Auteur ; Gulay Bayramoglu, Auteur ; Begum Altintas, Auteur Année de publication : 2011 Article en page(s) : pp. 9655–9665 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Copolymer Nanocomposite Microspheres Résumé : Functional hairy poly(styrene-b-glycidylmethacrylate) (P(S-GMA)) brushes were generated by grafting from bromoacetylated poly(styrene-divinylbenzene) (P(S-DVB)) microspheres via surface-initiated atom transfer radical polymerization (SI-ATRP). Two different approaches for the covalent immobilization of lipase onto microspheres were studied for the first time: (1) direct immobilization of lipase to the polymer brushes via their epoxy groups, and (2) immobilization of lipase via glutaraldehyde coupling after attachment of a spacer arm (hexamethylendiamine (HMDA)) to the polymer brushes. The covalent immobilization of the lipase on microspheres after spacer-arm attachment and glutaraldeyhde coupling was found to be the more effective than the direct binding method. In this case, a maximum value of the immobilized enzyme activity 498.5 U g−1 was found with an enzyme loading of 27.6 mg per gram of support. Thermal and storage stabilities increase upon immobilization on the P(S-DVB)-g-P(S-GMA)-HMDA-GA microspheres. Finally, esterification reactions have been performed to produce ethyl acetate and isoamyl acetate in a solvent-free system and in n-hexane using lipase-immobilized P(S-DVB)-g-P(S-GMA)-HMDA-GA microspheres. The immobilized lipase was effectively reused in successive batch runs in a solvent-free system for isoamyl acetate synthesis, and only 21% activity was lost after 10 cycles. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101351u
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9655–9665[article] Poly (glycidyl methacrylate) - polystyrene diblocks copolymer grafted nanocomposite microspheres from surface - initiated atom transfer radical polymerization for lipase immobilization : Application in flavor ester synthesis [texte imprimé] / Bunyamin Karagoz, Auteur ; Gulay Bayramoglu, Auteur ; Begum Altintas, Auteur . - 2011 . - pp. 9655–9665.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9655–9665
Mots-clés : Copolymer Nanocomposite Microspheres Résumé : Functional hairy poly(styrene-b-glycidylmethacrylate) (P(S-GMA)) brushes were generated by grafting from bromoacetylated poly(styrene-divinylbenzene) (P(S-DVB)) microspheres via surface-initiated atom transfer radical polymerization (SI-ATRP). Two different approaches for the covalent immobilization of lipase onto microspheres were studied for the first time: (1) direct immobilization of lipase to the polymer brushes via their epoxy groups, and (2) immobilization of lipase via glutaraldehyde coupling after attachment of a spacer arm (hexamethylendiamine (HMDA)) to the polymer brushes. The covalent immobilization of the lipase on microspheres after spacer-arm attachment and glutaraldeyhde coupling was found to be the more effective than the direct binding method. In this case, a maximum value of the immobilized enzyme activity 498.5 U g−1 was found with an enzyme loading of 27.6 mg per gram of support. Thermal and storage stabilities increase upon immobilization on the P(S-DVB)-g-P(S-GMA)-HMDA-GA microspheres. Finally, esterification reactions have been performed to produce ethyl acetate and isoamyl acetate in a solvent-free system and in n-hexane using lipase-immobilized P(S-DVB)-g-P(S-GMA)-HMDA-GA microspheres. The immobilized lipase was effectively reused in successive batch runs in a solvent-free system for isoamyl acetate synthesis, and only 21% activity was lost after 10 cycles. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101351u Exemplaires
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Titre : Oxidation of 6 - aminopenicillanic acid by diperiodatoargantate (III) in aqueous alkaline medium : A kinetic and mechanistic study Type de document : texte imprimé Auteurs : Shridhar D. Gunagi, Auteur ; Praveen N. Naik, Auteur ; Sharanappa T. Nandibewoor, Auteur Année de publication : 2011 Article en page(s) : pp. 9666–9672 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Oxidation Kinetic Résumé : Many pharmaceutical compounds and metabolites are being found in surface and ground waters, indicating their ineffective removal by conventional wastewater treatment technologies. Advanced oxidation processes for the transformation of 6-aminopenicillanic acid in water are alternatives to traditional water treatment. Therefore the kinetics of oxidation of 6-aminopenicillanic acid by diperiodatoargentate(III) in alkaline medium at a constant ionic strength of 0.04 mol dm−3 was studied spectrophotometrically at 25 °C. The oxidation products, 2-formyl-5,5-dimethylthiazolidine-4-carboxylic acid and Ag(I), were identified by LC-ESI-MS and IR spectral studies. The reaction between 6-aminopenicillanic acid and diperiodatoargentate(III) in alkaline medium exhibits 1:1 stoichiometry. The reaction shows first order with respect to diperiodatoargentate(III) concentration. The order with respect to 6-aminopenicillanic acid and alkali concentrations is less than unity. The rate goes on decreasing with the increase in the concentration of periodate. Monoperiodatoargentate(III) is considered the active species of the diperiodatoargentate(III). A possible mechanism is proposed. The reaction constants involved in the different steps of the mechanisms are determined. The activation parameters with respect to the slow step of the mechanism are calculated and discussed. The thermodynamic quantities are also determined. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9012562
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9666–9672[article] Oxidation of 6 - aminopenicillanic acid by diperiodatoargantate (III) in aqueous alkaline medium : A kinetic and mechanistic study [texte imprimé] / Shridhar D. Gunagi, Auteur ; Praveen N. Naik, Auteur ; Sharanappa T. Nandibewoor, Auteur . - 2011 . - pp. 9666–9672.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9666–9672
Mots-clés : Oxidation Kinetic Résumé : Many pharmaceutical compounds and metabolites are being found in surface and ground waters, indicating their ineffective removal by conventional wastewater treatment technologies. Advanced oxidation processes for the transformation of 6-aminopenicillanic acid in water are alternatives to traditional water treatment. Therefore the kinetics of oxidation of 6-aminopenicillanic acid by diperiodatoargentate(III) in alkaline medium at a constant ionic strength of 0.04 mol dm−3 was studied spectrophotometrically at 25 °C. The oxidation products, 2-formyl-5,5-dimethylthiazolidine-4-carboxylic acid and Ag(I), were identified by LC-ESI-MS and IR spectral studies. The reaction between 6-aminopenicillanic acid and diperiodatoargentate(III) in alkaline medium exhibits 1:1 stoichiometry. The reaction shows first order with respect to diperiodatoargentate(III) concentration. The order with respect to 6-aminopenicillanic acid and alkali concentrations is less than unity. The rate goes on decreasing with the increase in the concentration of periodate. Monoperiodatoargentate(III) is considered the active species of the diperiodatoargentate(III). A possible mechanism is proposed. The reaction constants involved in the different steps of the mechanisms are determined. The activation parameters with respect to the slow step of the mechanism are calculated and discussed. The thermodynamic quantities are also determined. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9012562 Exemplaires
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Titre : Reactive distillation for fischer − tropsch synthesis : Simulation - based design methodology using aspen plus Type de document : texte imprimé Auteurs : Seethamraju Srinivas, Auteur ; Sanjay M. Mahajani, Auteur ; Ranjan K. Malik, Auteur Année de publication : 2011 Article en page(s) : pp. 9673–9692 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Simulations Reactive distillation Résumé : In a series of earlier papers, it has been shown through simulations in Aspen Plus that reactive distillation (RD) is feasible for Fischer−Tropsch Synthesis (FTS) [Srinivas et al., Ind. Eng. Chem. Res. 2009, 48, 4710−4718]. The flexibility offered by changing parameters such as reflux ratio, etc. has also been investigated through parametric studies [Srinivas et al., Ind. Eng. Chem. Res. 2009, 48, 4719−4730]. As an extension of the previous works, a methodology is now proposed to design a RD column for FTS in Aspen Plus, utilizing the kinetic and thermodynamic models reported previously. Slurry reactor simulations are performed initially to form a design basis and a simple RD column is configured. This is followed by catalyst redistribution, addition of coolers, nonreactive stages, and side draws. The methodology is illustrated step-by-step for three examples in a systematic manner. The possibility of multiple designs, expected difficulties in execution, and limitations of the algorithm are discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100108p
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9673–9692[article] Reactive distillation for fischer − tropsch synthesis : Simulation - based design methodology using aspen plus [texte imprimé] / Seethamraju Srinivas, Auteur ; Sanjay M. Mahajani, Auteur ; Ranjan K. Malik, Auteur . - 2011 . - pp. 9673–9692.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9673–9692
Mots-clés : Simulations Reactive distillation Résumé : In a series of earlier papers, it has been shown through simulations in Aspen Plus that reactive distillation (RD) is feasible for Fischer−Tropsch Synthesis (FTS) [Srinivas et al., Ind. Eng. Chem. Res. 2009, 48, 4710−4718]. The flexibility offered by changing parameters such as reflux ratio, etc. has also been investigated through parametric studies [Srinivas et al., Ind. Eng. Chem. Res. 2009, 48, 4719−4730]. As an extension of the previous works, a methodology is now proposed to design a RD column for FTS in Aspen Plus, utilizing the kinetic and thermodynamic models reported previously. Slurry reactor simulations are performed initially to form a design basis and a simple RD column is configured. This is followed by catalyst redistribution, addition of coolers, nonreactive stages, and side draws. The methodology is illustrated step-by-step for three examples in a systematic manner. The possibility of multiple designs, expected difficulties in execution, and limitations of the algorithm are discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100108p Exemplaires
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Titre : Kinetics of CO2 absorption in aqueous sarcosine salt solutions : Influence of concentration, temperature, and CO2 loading Type de document : texte imprimé Auteurs : Katja Simons, Auteur ; Wim (D. W. F.) Brilman, Auteur ; Harro Mengers, Auteur Année de publication : 2011 Article en page(s) : pp. 9693–9702 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Loading Gas absorption Carbon dioxide Kinetics Résumé : Amino acid salt solutions are a promising alternative to alkanolamines (e.g., MEA) as absorption liquid for CO2 removal due to their ionic nature, their low evaporative losses, and their assumed higher oxidative and thermal stability. Sarcosine is a promising candidate because of its relatively high CO2 loading capacity and reactivity. In this work, CO2 absorption experiments in the so-called pseudo-first-order regime were carried out to determine the reaction rate expression and reaction rate constant of CO2 absorption in aqueous sarcosine salt solutions. Next to the influence of the sarcosine concentration (0.5−3.8 M) and the temperature (298−308 K) on the rate of reaction, the reaction rate constants for partially loaded sarcosinate solutions were investigated. Compared to MEA, very high reaction rate constants for the carbamate formation were obtained for aqueous sarcosine salt solutions. The reaction order in CO2 was found to be equal to 1, which is in accordance with the literature, and for potassium sarcosinate an (apparent) reaction order of 1.66 was found. The activation energy was found to be approximately 26 kJ/mol. The apparent rate of the reaction strongly decreases with increasing partial loading of the solution with CO2 and was found to be directly related to the decrease in free amine concentration in the solution. This observation is especially relevant for cyclic absorption processes such as gas−liquid membrane contactors, where incomplete solvent regeneration occurs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325788
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9693–9702[article] Kinetics of CO2 absorption in aqueous sarcosine salt solutions : Influence of concentration, temperature, and CO2 loading [texte imprimé] / Katja Simons, Auteur ; Wim (D. W. F.) Brilman, Auteur ; Harro Mengers, Auteur . - 2011 . - pp. 9693–9702.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9693–9702
Mots-clés : Loading Gas absorption Carbon dioxide Kinetics Résumé : Amino acid salt solutions are a promising alternative to alkanolamines (e.g., MEA) as absorption liquid for CO2 removal due to their ionic nature, their low evaporative losses, and their assumed higher oxidative and thermal stability. Sarcosine is a promising candidate because of its relatively high CO2 loading capacity and reactivity. In this work, CO2 absorption experiments in the so-called pseudo-first-order regime were carried out to determine the reaction rate expression and reaction rate constant of CO2 absorption in aqueous sarcosine salt solutions. Next to the influence of the sarcosine concentration (0.5−3.8 M) and the temperature (298−308 K) on the rate of reaction, the reaction rate constants for partially loaded sarcosinate solutions were investigated. Compared to MEA, very high reaction rate constants for the carbamate formation were obtained for aqueous sarcosine salt solutions. The reaction order in CO2 was found to be equal to 1, which is in accordance with the literature, and for potassium sarcosinate an (apparent) reaction order of 1.66 was found. The activation energy was found to be approximately 26 kJ/mol. The apparent rate of the reaction strongly decreases with increasing partial loading of the solution with CO2 and was found to be directly related to the decrease in free amine concentration in the solution. This observation is especially relevant for cyclic absorption processes such as gas−liquid membrane contactors, where incomplete solvent regeneration occurs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325788 Exemplaires
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Titre : Modeling the influence of wood anisotropy and internal diffusion on delignification kinetics Type de document : texte imprimé Auteurs : Henrik Grenman, Auteur ; Johan Warna, Auteur ; J.-P. Mikkola, Auteur Année de publication : 2011 Article en page(s) : pp. 9703–9711 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetics Internal diffusion Anisotropy Wood Modeling Résumé : A general mathematical model for the chemical pulping of wood including coupled chemical reactions and diffusion limitations in anisotropic wood chips was developed. The model, which consists of coupled parabolic partial differential equations (PDEs) and ordinary differential equations (ODEs), describes the time-dependent behavior of wood chips as they are exposed to chemicals in the liquid phase. In addition to the reaction−diffusion phenomena, the model describes the change of the wood chip porosity during the process. A numerical algorithm that combines spatial discretization by finite differences with a stiff ODE solver based on the backward difference method was used as an efficient strategy to solve the mass balances of wood chips in batch reactors. Numerical simulations with the software can be used to predict the progress of industrial delignification, that is, production of primarily cellulose through chemical pulping. The effect of the reaction parameters, such as the temperature and the concentrations of the alkaline delignification chemicals, as well as the sizes of the wood chips, can be evaluated with the model, the final goal being the intensification of the chemical pulping process. The model can be used to describe both the current kraft pulping (sulfate pulping) technique, as well as other processes, such as sulfite pulping and pulping in nonaqueous solvents. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325789
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9703–9711[article] Modeling the influence of wood anisotropy and internal diffusion on delignification kinetics [texte imprimé] / Henrik Grenman, Auteur ; Johan Warna, Auteur ; J.-P. Mikkola, Auteur . - 2011 . - pp. 9703–9711.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9703–9711
Mots-clés : Kinetics Internal diffusion Anisotropy Wood Modeling Résumé : A general mathematical model for the chemical pulping of wood including coupled chemical reactions and diffusion limitations in anisotropic wood chips was developed. The model, which consists of coupled parabolic partial differential equations (PDEs) and ordinary differential equations (ODEs), describes the time-dependent behavior of wood chips as they are exposed to chemicals in the liquid phase. In addition to the reaction−diffusion phenomena, the model describes the change of the wood chip porosity during the process. A numerical algorithm that combines spatial discretization by finite differences with a stiff ODE solver based on the backward difference method was used as an efficient strategy to solve the mass balances of wood chips in batch reactors. Numerical simulations with the software can be used to predict the progress of industrial delignification, that is, production of primarily cellulose through chemical pulping. The effect of the reaction parameters, such as the temperature and the concentrations of the alkaline delignification chemicals, as well as the sizes of the wood chips, can be evaluated with the model, the final goal being the intensification of the chemical pulping process. The model can be used to describe both the current kraft pulping (sulfate pulping) technique, as well as other processes, such as sulfite pulping and pulping in nonaqueous solvents. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325789 Exemplaires
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Titre : Kinetic modeling of autothermal reforming of dimethyl ether Type de document : texte imprimé Auteurs : Derek Creaser, Auteur ; Marita Nilsson, Auteur ; Lars J. Pettersson, Auteur Année de publication : 2011 Article en page(s) : pp. 9712–9719 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetic Autothermal Résumé : A global kinetic model was developed for the autothermal reforming of dimethyl ether (DME) over a Pd−Zn/Al2O3 catalyst on a cordierite monolith. A kinetic model consisting of five key overall reactions was found to capture the main features of experimental data. The modeling also accounted for heat transport effects in the reactor that are of importance when coupling the exothermic oxidation reactions with endothermic steam reforming reactions. The modeling confirmed that oxidation reactions dominate near the inlet of the reactor, generating a local hot spot. The heat from oxidation reactions accelerates the reforming reactions. Water adsorption was found to have a weak detrimental influence on the activity. On the basis of the model, the influence of the reactor scale and oxygen supply by air feed on the performance of the reactor was examined. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100834v
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9712–9719[article] Kinetic modeling of autothermal reforming of dimethyl ether [texte imprimé] / Derek Creaser, Auteur ; Marita Nilsson, Auteur ; Lars J. Pettersson, Auteur . - 2011 . - pp. 9712–9719.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9712–9719
Mots-clés : Kinetic Autothermal Résumé : A global kinetic model was developed for the autothermal reforming of dimethyl ether (DME) over a Pd−Zn/Al2O3 catalyst on a cordierite monolith. A kinetic model consisting of five key overall reactions was found to capture the main features of experimental data. The modeling also accounted for heat transport effects in the reactor that are of importance when coupling the exothermic oxidation reactions with endothermic steam reforming reactions. The modeling confirmed that oxidation reactions dominate near the inlet of the reactor, generating a local hot spot. The heat from oxidation reactions accelerates the reforming reactions. Water adsorption was found to have a weak detrimental influence on the activity. On the basis of the model, the influence of the reactor scale and oxygen supply by air feed on the performance of the reactor was examined. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100834v Exemplaires
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Titre : Experimental investigation of a CuO/Al2O3 oxygen carrier for chemical - looping combustion Type de document : texte imprimé Auteurs : Sander Noorman, Auteur ; Fausto Gallucci, Auteur ; Martin Van Sint Annaland, Auteur Année de publication : 2011 Article en page(s) : pp. 9720–9728 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Oxygen carrier Combustion Résumé : Chemical-looping combustion (CLC) has emerged as an interesting alternative for conventional power production technologies, intrinsically combining power production and CO2 capture. The performance of the oxygen carrier particles used in this technology is of vital importance for the overall technical and economical feasibility of CLC technology, and therefore, the behavior of a selected oxygen carrier (CuO/Al2O3) has been investigated in more detail using thermogravimetry. The experimental study focused on the reactivity during the oxidation and reduction cycles and the stability of the particles over multiple alternating sequences of these cycles. Particles of relatively large size were used, to investigate the possibility of using the material in packed-bed CLC. Interpretation of the experimental results on a quantitative level was achieved through comparison with numerical simulations using a detailed particle model in which the effects of both reaction kinetics and intraparticle mass-transfer limitations were fully taken into account. It was found that the experimentally determined conversion rate of the particles during oxidation could be very well described by the particle model that accounts for changes in the particle morphology. The average pore size needed in the simulations to reproduce the experimental results matched well with the most common pore size found by nitrogen adsorption−desorption experiments using the BET and BJH methods. For the reduction cycles using hydrogen as the reducing agent, it was concluded that the conversion characteristics could be described reasonably well for moderate conversions, but for higher conversions, the discrepancies were larger, especially at rather low operating temperatures. When reduction cycles were carried out with methane, carbon deposition was observed. The generated data and insights help in assessing the optimal reactor configuration for CLC and its feasibility. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100869t
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9720–9728[article] Experimental investigation of a CuO/Al2O3 oxygen carrier for chemical - looping combustion [texte imprimé] / Sander Noorman, Auteur ; Fausto Gallucci, Auteur ; Martin Van Sint Annaland, Auteur . - 2011 . - pp. 9720–9728.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9720–9728
Mots-clés : Oxygen carrier Combustion Résumé : Chemical-looping combustion (CLC) has emerged as an interesting alternative for conventional power production technologies, intrinsically combining power production and CO2 capture. The performance of the oxygen carrier particles used in this technology is of vital importance for the overall technical and economical feasibility of CLC technology, and therefore, the behavior of a selected oxygen carrier (CuO/Al2O3) has been investigated in more detail using thermogravimetry. The experimental study focused on the reactivity during the oxidation and reduction cycles and the stability of the particles over multiple alternating sequences of these cycles. Particles of relatively large size were used, to investigate the possibility of using the material in packed-bed CLC. Interpretation of the experimental results on a quantitative level was achieved through comparison with numerical simulations using a detailed particle model in which the effects of both reaction kinetics and intraparticle mass-transfer limitations were fully taken into account. It was found that the experimentally determined conversion rate of the particles during oxidation could be very well described by the particle model that accounts for changes in the particle morphology. The average pore size needed in the simulations to reproduce the experimental results matched well with the most common pore size found by nitrogen adsorption−desorption experiments using the BET and BJH methods. For the reduction cycles using hydrogen as the reducing agent, it was concluded that the conversion characteristics could be described reasonably well for moderate conversions, but for higher conversions, the discrepancies were larger, especially at rather low operating temperatures. When reduction cycles were carried out with methane, carbon deposition was observed. The generated data and insights help in assessing the optimal reactor configuration for CLC and its feasibility. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100869t Exemplaires
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Titre : Removal of orange II dye in water by visible light assisted photocatalytic ozonation using Bi2O3 and Au /Bi2O3 nanorods Type de document : texte imprimé Auteurs : Sambandam Anandan, Auteur ; Gang-Juan Lee, Auteur ; Pei-Kuan Chen, Auteur Année de publication : 2011 Article en page(s) : pp. 9729–9737 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ozonization Photocatalysis Visible radiation Dyes Résumé : This paper presents the results of visible light assisted photocatalytic ozonation and other related oxidation processes for the removal of Orange II dye from water using Bi2O3 and Au/Bi2O3 nanorods prepared using microwave irradiation which was found effective compared to Bi2O3 particles prepared by conventional heat treatment method at 90 °C. Particularly, in the photocatalytic ozonation using Au/Bi2O3 nanorods, a fourfold increase in the rate was observed as compared to that in the absence of Au/Bi2O3. This is because tuning semiconductor materials into nanosize could create high quantum confinement of electron and hole to increase the illumination efficiency. In addition, the deposition of nanomaterial can also be employed to enhance the mechanical strength of devices. That is, deposited Au nanoparticles act as electron traps to impede electron/hole recombination. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325792
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9729–9737[article] Removal of orange II dye in water by visible light assisted photocatalytic ozonation using Bi2O3 and Au /Bi2O3 nanorods [texte imprimé] / Sambandam Anandan, Auteur ; Gang-Juan Lee, Auteur ; Pei-Kuan Chen, Auteur . - 2011 . - pp. 9729–9737.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9729–9737
Mots-clés : Ozonization Photocatalysis Visible radiation Dyes Résumé : This paper presents the results of visible light assisted photocatalytic ozonation and other related oxidation processes for the removal of Orange II dye from water using Bi2O3 and Au/Bi2O3 nanorods prepared using microwave irradiation which was found effective compared to Bi2O3 particles prepared by conventional heat treatment method at 90 °C. Particularly, in the photocatalytic ozonation using Au/Bi2O3 nanorods, a fourfold increase in the rate was observed as compared to that in the absence of Au/Bi2O3. This is because tuning semiconductor materials into nanosize could create high quantum confinement of electron and hole to increase the illumination efficiency. In addition, the deposition of nanomaterial can also be employed to enhance the mechanical strength of devices. That is, deposited Au nanoparticles act as electron traps to impede electron/hole recombination. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325792 Exemplaires
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Titre : Selection of best indicators for ranking and determination of bottleneck enzymes in metabolic reaction systems Type de document : texte imprimé Auteurs : Kansuporn Sriyudthsak, Auteur ; Fumihide Shiraishi, Auteur Année de publication : 2011 Article en page(s) : pp. 9738–9742 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Enzymes Metabolic reaction Résumé : Dynamic logarithmic gain and its modifications can be theoretically used as a bottleneck ranking (BR) indicator in a metabolic reaction system. However, it is not sufficiently explicit whether they can be successfully used in practical applications. The present work therefore focuses on the selection of best BR indicators in both instantaneous and overall cases. A modified ethanol fermentation model is used as a case study. The results indicate that the mathematical product of dynamic logarithmic gain and desired product concentration at a given time is the best instantaneous BR indicator, whereas its value at the end time of the fermentation process is the best overall BR indicator. The former is useful for observing the time course of the desired product concentration and determining a process time to be terminated. The latter is for ranking bottleneck enzymes to determine which enzyme activity should be changed to attain a higher desired product concentration. Moreover, discussion is made on the utilization of the overall BR indicators to predict how much the final desired product concentration is increased. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100911h
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9738–9742[article] Selection of best indicators for ranking and determination of bottleneck enzymes in metabolic reaction systems [texte imprimé] / Kansuporn Sriyudthsak, Auteur ; Fumihide Shiraishi, Auteur . - 2011 . - pp. 9738–9742.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9738–9742
Mots-clés : Enzymes Metabolic reaction Résumé : Dynamic logarithmic gain and its modifications can be theoretically used as a bottleneck ranking (BR) indicator in a metabolic reaction system. However, it is not sufficiently explicit whether they can be successfully used in practical applications. The present work therefore focuses on the selection of best BR indicators in both instantaneous and overall cases. A modified ethanol fermentation model is used as a case study. The results indicate that the mathematical product of dynamic logarithmic gain and desired product concentration at a given time is the best instantaneous BR indicator, whereas its value at the end time of the fermentation process is the best overall BR indicator. The former is useful for observing the time course of the desired product concentration and determining a process time to be terminated. The latter is for ranking bottleneck enzymes to determine which enzyme activity should be changed to attain a higher desired product concentration. Moreover, discussion is made on the utilization of the overall BR indicators to predict how much the final desired product concentration is increased. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100911h Exemplaires
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Titre : Pyrolysis of corncobs catalyzed by zinc chloride for furfural production Type de document : texte imprimé Auteurs : C. Branca, Auteur ; C. Di Blasi, Auteur ; A. Galgano, Auteur Année de publication : 2011 Article en page(s) : pp. 9743–9752 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Production Catalytic reaction Pyrolysis Résumé : The pyrolysis of corncobs impregnated with variable amounts of zinc chloride (ZnCl2) (up to 11%, on a dry sample mass basis) is investigated and compared with fir wood results. As expected, a continuous increase with the amount of impregnated catalyst in corncobs is observed of the formation rates of char and water (total yields from 46% up to 64%) associated with a decline in the yields of organic condensable products (from 38% to 18%) and gas (from 13% to 9%). Moderate ZnCl2 concentrations (2%−5%) favor the production of levoglucosenone (from trace amounts to 1%), acetic acid (from 4% to 6%), and furfural (from 0.65% to 6%). Moreover, low values, although causing the prompt decay in the yields of hydroxyacetaldehyde, hydroxypropanone, levoglucosan, minor carbohydrates, phenols, and guaiacols, enhance the formation rate of 5-hydroxy-methylfurfural, 4-hydroxy-5,6-dihydro-(2H)-pyran-2-one, 1-hydroxy-3,6-dioxabicyclo[3.2.1]octan-2-one, and 1,4:3,6-dianhydro-α-d-glucopyranose. Results support the speculation that dehydrated cellulose and galactoglucomannan hemicellulose produce levoglucosenone and 1,4:3,6-dianhydro-α-d-glucopyranose, instead of levoglucosan, which are then catalytically decomposed to other products, including furfural. ZnCl2 also catalyzes the primary paths of furfural formation via dehydration of pentosyl and glucosyl residues, with a stronger action on the former. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325794
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9743–9752[article] Pyrolysis of corncobs catalyzed by zinc chloride for furfural production [texte imprimé] / C. Branca, Auteur ; C. Di Blasi, Auteur ; A. Galgano, Auteur . - 2011 . - pp. 9743–9752.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9743–9752
Mots-clés : Production Catalytic reaction Pyrolysis Résumé : The pyrolysis of corncobs impregnated with variable amounts of zinc chloride (ZnCl2) (up to 11%, on a dry sample mass basis) is investigated and compared with fir wood results. As expected, a continuous increase with the amount of impregnated catalyst in corncobs is observed of the formation rates of char and water (total yields from 46% up to 64%) associated with a decline in the yields of organic condensable products (from 38% to 18%) and gas (from 13% to 9%). Moderate ZnCl2 concentrations (2%−5%) favor the production of levoglucosenone (from trace amounts to 1%), acetic acid (from 4% to 6%), and furfural (from 0.65% to 6%). Moreover, low values, although causing the prompt decay in the yields of hydroxyacetaldehyde, hydroxypropanone, levoglucosan, minor carbohydrates, phenols, and guaiacols, enhance the formation rate of 5-hydroxy-methylfurfural, 4-hydroxy-5,6-dihydro-(2H)-pyran-2-one, 1-hydroxy-3,6-dioxabicyclo[3.2.1]octan-2-one, and 1,4:3,6-dianhydro-α-d-glucopyranose. Results support the speculation that dehydrated cellulose and galactoglucomannan hemicellulose produce levoglucosenone and 1,4:3,6-dianhydro-α-d-glucopyranose, instead of levoglucosan, which are then catalytically decomposed to other products, including furfural. ZnCl2 also catalyzes the primary paths of furfural formation via dehydration of pentosyl and glucosyl residues, with a stronger action on the former. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325794 Exemplaires
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Titre : Making sense of the fischer − tropsch synthesis reaction : Start - up Type de document : texte imprimé Auteurs : Xiaojun Lu, Auteur ; Diane Hildebrandt, Auteur ; Xinying Liu, Auteur Année de publication : 2011 Article en page(s) : pp. 9753–9758 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Fischer tropsch reaction Résumé : Conventional Fischer−Tropsch experiments were conducted to investigate the early stages (start-up) of the reaction of a TiO2-supported cobalt catalyst in a continuous stirred tank reactor and compared to the later stages. Thus, both short-term and long-term experiments were performed starting with fresh catalysts in each case. The experimental results showed that stirrer speed had an influence on the Fischer−Tropsch performance only in the short term. This suggested that under typical reaction conditions in a gas−solid system, long-term the Fischer−Tropsch reaction is not controlled by external mass transfer. After between about 30 and 80 h (depending on the temperature), large changes in reaction rate and product selectivity were observed, and these time-on-stream experiments showed that these changes were caused neither by the reaction conditions nor by the external mass transfer. Two possible explanations are proposed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1011933
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9753–9758[article] Making sense of the fischer − tropsch synthesis reaction : Start - up [texte imprimé] / Xiaojun Lu, Auteur ; Diane Hildebrandt, Auteur ; Xinying Liu, Auteur . - 2011 . - pp. 9753–9758.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9753–9758
Mots-clés : Fischer tropsch reaction Résumé : Conventional Fischer−Tropsch experiments were conducted to investigate the early stages (start-up) of the reaction of a TiO2-supported cobalt catalyst in a continuous stirred tank reactor and compared to the later stages. Thus, both short-term and long-term experiments were performed starting with fresh catalysts in each case. The experimental results showed that stirrer speed had an influence on the Fischer−Tropsch performance only in the short term. This suggested that under typical reaction conditions in a gas−solid system, long-term the Fischer−Tropsch reaction is not controlled by external mass transfer. After between about 30 and 80 h (depending on the temperature), large changes in reaction rate and product selectivity were observed, and these time-on-stream experiments showed that these changes were caused neither by the reaction conditions nor by the external mass transfer. Two possible explanations are proposed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1011933 Exemplaires
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Titre : Reactions of indan over zeolite catalysts Type de document : texte imprimé Auteurs : Xiaojing Cheng, Auteur ; Guang Xiong, Auteur ; Xinwen Guo, Auteur Année de publication : 2011 Article en page(s) : pp. 9759–9763 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Zeolite Catalysts Résumé : The reactions of indan were studied over ZSM-5, zeolite β, and mordenite under atmospheric pressure or 3 MPa. Zeolite β shows the best catalytic activity. The main reaction pathways of indan are five-membered ring opening and condensation. The ring-opening reaction of indan follows β scission mechanism. No hydrogenation of indan occurs. When the reaction temperature or the concentration of indan is high, it tends to condensate to form polyaromatics. No effect of aromatics such as benzene or trimethylbenzene was found in the reactions of indan. The existence of indan decreases the conversion of trimethylbenzene because of its preferential adsorption on the catalysts. The amount of indan in the reactant strongly affects the coke amount of the catalyst. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1012085
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9759–9763[article] Reactions of indan over zeolite catalysts [texte imprimé] / Xiaojing Cheng, Auteur ; Guang Xiong, Auteur ; Xinwen Guo, Auteur . - 2011 . - pp. 9759–9763.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9759–9763
Mots-clés : Zeolite Catalysts Résumé : The reactions of indan were studied over ZSM-5, zeolite β, and mordenite under atmospheric pressure or 3 MPa. Zeolite β shows the best catalytic activity. The main reaction pathways of indan are five-membered ring opening and condensation. The ring-opening reaction of indan follows β scission mechanism. No hydrogenation of indan occurs. When the reaction temperature or the concentration of indan is high, it tends to condensate to form polyaromatics. No effect of aromatics such as benzene or trimethylbenzene was found in the reactions of indan. The existence of indan decreases the conversion of trimethylbenzene because of its preferential adsorption on the catalysts. The amount of indan in the reactant strongly affects the coke amount of the catalyst. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1012085 Exemplaires
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Titre : Long - term deactivation of supported Pt catalysts in the dehydrogenation of methylcyclohexane to toluene Type de document : texte imprimé Auteurs : Faisal Alhumaidan, Auteur ; David Cresswel, Auteur ; Arthur Garforth, Auteur Année de publication : 2011 Article en page(s) : pp. 9764–9770 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : kinetics Methylcyclohexane Résumé : The kinetics of methylcyclohexane (MCH) dehydrogenation over supported Pt catalysts was successfully described by a non-Langmuirian/noncompetitive Horiuti−Polanyi model (Ind. Eng. Chem. Res., in press). The daily reversible and irreversible deactivation, associated with activity tests, was satisfactorily included in the dehydrogenation model. The objective of this work is to incorporate the long-term deactivation of Pt catalysts, associated with life or deactivation tests, in the kinetic model. This has been successfully achieved by assuming that the long-term deactivation is the sum of two exponential decay processes, one rapid and completed in a few days, while the other is slow with a half-life of weeks to months. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1013025
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9764–9770[article] Long - term deactivation of supported Pt catalysts in the dehydrogenation of methylcyclohexane to toluene [texte imprimé] / Faisal Alhumaidan, Auteur ; David Cresswel, Auteur ; Arthur Garforth, Auteur . - 2011 . - pp. 9764–9770.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9764–9770
Mots-clés : kinetics Methylcyclohexane Résumé : The kinetics of methylcyclohexane (MCH) dehydrogenation over supported Pt catalysts was successfully described by a non-Langmuirian/noncompetitive Horiuti−Polanyi model (Ind. Eng. Chem. Res., in press). The daily reversible and irreversible deactivation, associated with activity tests, was satisfactorily included in the dehydrogenation model. The objective of this work is to incorporate the long-term deactivation of Pt catalysts, associated with life or deactivation tests, in the kinetic model. This has been successfully achieved by assuming that the long-term deactivation is the sum of two exponential decay processes, one rapid and completed in a few days, while the other is slow with a half-life of weeks to months. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1013025 Exemplaires
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Titre : Efficient methodologies for processing of fluids by thermal convection within porous square cavities Type de document : texte imprimé Auteurs : Ram Satish Kaluri, Auteur ; Tanmay Basak, Auteur Année de publication : 2011 Article en page(s) : pp. 9771–9788 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Fluids thermal Cavities Résumé : Effective use of thermal energy is the key for the energy-efficient processing of materials. A proper understanding of heat flow would be very useful in designing the systems of high energy efficiency with a minimal waste of precious energy resources. In the current study, a distributed heating methodology is proposed for the efficient thermal processing of materials. A detailed investigation on the processing of various fluids of industrial importance (with a Prandtl number of Pr = 0.015, 0.7, 10, and 1000) in differentially and discretely heated porous square cavities is presented. Analysis of laminar convective heat flow within a range of Darcy number, Da = 10−6−10−3 and Rayleigh number, Ra = 103−106 has been carried out, based on a heatline visualization approach. The effect of Da and the role of distributed heating in enhancing the convection in the cavities is illustrated via heatline distributions, which represent the paths of the heat flow, the magnitude of heat flow, and zones of high heat transfer. It is observed that distributed heating plays an important role in enhancement of thermal mixing and temperature uniformity. Furthermore, the effect of Da for various Pr values on the variation of local Nusselt number (Nu) is analyzed, based on heatline distributions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100569w
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9771–9788[article] Efficient methodologies for processing of fluids by thermal convection within porous square cavities [texte imprimé] / Ram Satish Kaluri, Auteur ; Tanmay Basak, Auteur . - 2011 . - pp. 9771–9788.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9771–9788
Mots-clés : Fluids thermal Cavities Résumé : Effective use of thermal energy is the key for the energy-efficient processing of materials. A proper understanding of heat flow would be very useful in designing the systems of high energy efficiency with a minimal waste of precious energy resources. In the current study, a distributed heating methodology is proposed for the efficient thermal processing of materials. A detailed investigation on the processing of various fluids of industrial importance (with a Prandtl number of Pr = 0.015, 0.7, 10, and 1000) in differentially and discretely heated porous square cavities is presented. Analysis of laminar convective heat flow within a range of Darcy number, Da = 10−6−10−3 and Rayleigh number, Ra = 103−106 has been carried out, based on a heatline visualization approach. The effect of Da and the role of distributed heating in enhancing the convection in the cavities is illustrated via heatline distributions, which represent the paths of the heat flow, the magnitude of heat flow, and zones of high heat transfer. It is observed that distributed heating plays an important role in enhancement of thermal mixing and temperature uniformity. Furthermore, the effect of Da for various Pr values on the variation of local Nusselt number (Nu) is analyzed, based on heatline distributions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100569w Exemplaires
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Titre : A conjugated polymer network approach to anticorrosion coatings : Poly (vinylcarbazole) electrodeposition Type de document : texte imprimé Auteurs : Antonio F. Frau, Auteur ; Roderick B. Pernites, Auteur ; Rigoberto C. Advincula, Auteur Année de publication : 2011 Article en page(s) : pp. 9789–9797 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Polymer Anticorrosion Résumé : The fabrication and characterization of poly(vinylcarbazole) (PVK)-conjugated polymer network (CPN) anticorrosion coatings on flat surfaces, steel coupons or indium tin oxide (ITO) glass substrates, is reported. Electrochemical deposition methods (potentiostatic and potentiodynamic) were employed by anodic oxidation of the carbazole side units in the PVK chains, resulting in electrodeposition of a cross-linked or network macromolecular structure. This is different from traditional conjugated polymer (CP) coatings made up of mostly linear species derived from direct electropolymerization of small molecule monomers. The coating composition was characterized by attenuated total reflection infrared spectroscopy (ATR-IR) and photoelectron spectroscopy (XPS). Atomic force microscopy (AFM) allowed morphological comparison between the coatings in terms of deposition technique and surface roughness. Electrochemical impedance spectroscopy (EIS) was subsequently carried out on PVK-coated steel coupons to evaluate the performance of such coatings in an accelerated corrosion environment. The deviation from the ideal (i.e., perfectly dielectric) capacitor-like behavior and Bode plot data suggested that the CPN approach of electrodeposited PVK coatings resulted in very good protection against weathering of engineering metals. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100813t
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9789–9797[article] A conjugated polymer network approach to anticorrosion coatings : Poly (vinylcarbazole) electrodeposition [texte imprimé] / Antonio F. Frau, Auteur ; Roderick B. Pernites, Auteur ; Rigoberto C. Advincula, Auteur . - 2011 . - pp. 9789–9797.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9789–9797
Mots-clés : Polymer Anticorrosion Résumé : The fabrication and characterization of poly(vinylcarbazole) (PVK)-conjugated polymer network (CPN) anticorrosion coatings on flat surfaces, steel coupons or indium tin oxide (ITO) glass substrates, is reported. Electrochemical deposition methods (potentiostatic and potentiodynamic) were employed by anodic oxidation of the carbazole side units in the PVK chains, resulting in electrodeposition of a cross-linked or network macromolecular structure. This is different from traditional conjugated polymer (CP) coatings made up of mostly linear species derived from direct electropolymerization of small molecule monomers. The coating composition was characterized by attenuated total reflection infrared spectroscopy (ATR-IR) and photoelectron spectroscopy (XPS). Atomic force microscopy (AFM) allowed morphological comparison between the coatings in terms of deposition technique and surface roughness. Electrochemical impedance spectroscopy (EIS) was subsequently carried out on PVK-coated steel coupons to evaluate the performance of such coatings in an accelerated corrosion environment. The deviation from the ideal (i.e., perfectly dielectric) capacitor-like behavior and Bode plot data suggested that the CPN approach of electrodeposited PVK coatings resulted in very good protection against weathering of engineering metals. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100813t Exemplaires
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Titre : High - performance rubber sealant for preventing water leaks Type de document : texte imprimé Auteurs : Morinobu Endo, Auteur ; Kenji Takeuchi, Auteur ; Toru Noguchi, Auteur Année de publication : 2011 Article en page(s) : pp. 9798-9802 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Leak Sealing material Résumé : Considerable amounts of water are being lost due to leaks. One of the main reasons for experiencing such large water leaks is the premature failure of rubber sealants in valves. Water leaks commonly originate from the presence of chlorine ions in tap water. Here, we demonstrate that the incorporation of surface-modified and highly crystalline carbon nanotubes allows the rubber sealants to maintain their sealing properties without experiencing any distinctive degradation over a wide range of temperature and environmental conditions over their expected lifetime. It is envisaged that environmentally friendly nanotechnology will save huge amounts of energy for purifying and transporting water around the whole world. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325800
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9798-9802[article] High - performance rubber sealant for preventing water leaks [texte imprimé] / Morinobu Endo, Auteur ; Kenji Takeuchi, Auteur ; Toru Noguchi, Auteur . - 2011 . - pp. 9798-9802.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9798-9802
Mots-clés : Leak Sealing material Résumé : Considerable amounts of water are being lost due to leaks. One of the main reasons for experiencing such large water leaks is the premature failure of rubber sealants in valves. Water leaks commonly originate from the presence of chlorine ions in tap water. Here, we demonstrate that the incorporation of surface-modified and highly crystalline carbon nanotubes allows the rubber sealants to maintain their sealing properties without experiencing any distinctive degradation over a wide range of temperature and environmental conditions over their expected lifetime. It is envisaged that environmentally friendly nanotechnology will save huge amounts of energy for purifying and transporting water around the whole world. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325800 Exemplaires
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Titre : A novel aromatic - aliphatic copolyester of poly (ethylene - co - diethylene terephthalate) - co - poly (l-lactic acid) : Synthesis and characterization Type de document : texte imprimé Auteurs : Jun Li, Auteur ; Zhi-Qiang Jiang, Auteur ; Jian Zhou, Auteur Année de publication : 2011 Article en page(s) : pp. 9803–9810 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Copolyester Résumé : Aromatic−aliphatic copolyesters of poly(ethylene-co-diethylene terephthalate)-co-poly(l-lactic acid) (PEDLT) with different compositions were synthesized by direct melt copolyesterization of l-lactic acid oligomers and poly(ethylene-co-diethylene terephthalate) (PEDT) oligomers. Chemical structures, thermal properties, and crystalline behaviors were studied. 1H NMR confirmed that the short lactyl units were incorporated into the PEDT chains. Thermogravimetric analysis showed that PEDLT copolyesters were thermally stable up to about 380 °C. Both wide-angle X-ray diffraction and Fourier transform infrared spectroscopy showed that no poly(l-lactic acid) crystal was formed during the crystallization of PEDLT copolyesters. Isothermal crystallization of PEDLT copolyesters was carried out, and it was found that both the crystallinity and crystal growth rate decreased after incorporation of lactyl units compared with those of PEDT. The obtained aromatic−aliphatic copolyesters are expected to find a potential application as biodegradable polymer materials. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100915y
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9803–9810[article] A novel aromatic - aliphatic copolyester of poly (ethylene - co - diethylene terephthalate) - co - poly (l-lactic acid) : Synthesis and characterization [texte imprimé] / Jun Li, Auteur ; Zhi-Qiang Jiang, Auteur ; Jian Zhou, Auteur . - 2011 . - pp. 9803–9810.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9803–9810
Mots-clés : Copolyester Résumé : Aromatic−aliphatic copolyesters of poly(ethylene-co-diethylene terephthalate)-co-poly(l-lactic acid) (PEDLT) with different compositions were synthesized by direct melt copolyesterization of l-lactic acid oligomers and poly(ethylene-co-diethylene terephthalate) (PEDT) oligomers. Chemical structures, thermal properties, and crystalline behaviors were studied. 1H NMR confirmed that the short lactyl units were incorporated into the PEDT chains. Thermogravimetric analysis showed that PEDLT copolyesters were thermally stable up to about 380 °C. Both wide-angle X-ray diffraction and Fourier transform infrared spectroscopy showed that no poly(l-lactic acid) crystal was formed during the crystallization of PEDLT copolyesters. Isothermal crystallization of PEDLT copolyesters was carried out, and it was found that both the crystallinity and crystal growth rate decreased after incorporation of lactyl units compared with those of PEDT. The obtained aromatic−aliphatic copolyesters are expected to find a potential application as biodegradable polymer materials. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100915y Exemplaires
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Titre : Protein imprinting by means of Aaginate - based polymer microcapsules Type de document : texte imprimé Auteurs : Edgar P. Herrero, Auteur ; Eva M. Martín Del Valle, Auteur ; Nicholas A. Peppas, Auteur Année de publication : 2011 Article en page(s) : pp. 9811-9814 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Microcapsule Résumé : Molecular imprinting is a promising technology that, although successfully used to recognize small molecules, has had many difficulties in recognizing macromolecules such as peptides and proteins. The current technologies used to achieve the macromolecular imprinting are incompatible with diagnosis and recognition in many life sciences applications such as medical devices, food additives, or drug delivery systems that require biocompatible products. We present here a new, biocompatible technology of protein imprinting by means of calcium alginate-based polymer capsules using ionic gelation and without toxic chemicals other than sodium alginate and calcium chloride. These molecular imprinting capsules are capable of recognizing higher quantities of protein than the existing technologies developed until now, with a simple formulation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325802
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9811-9814[article] Protein imprinting by means of Aaginate - based polymer microcapsules [texte imprimé] / Edgar P. Herrero, Auteur ; Eva M. Martín Del Valle, Auteur ; Nicholas A. Peppas, Auteur . - 2011 . - pp. 9811-9814.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9811-9814
Mots-clés : Microcapsule Résumé : Molecular imprinting is a promising technology that, although successfully used to recognize small molecules, has had many difficulties in recognizing macromolecules such as peptides and proteins. The current technologies used to achieve the macromolecular imprinting are incompatible with diagnosis and recognition in many life sciences applications such as medical devices, food additives, or drug delivery systems that require biocompatible products. We present here a new, biocompatible technology of protein imprinting by means of calcium alginate-based polymer capsules using ionic gelation and without toxic chemicals other than sodium alginate and calcium chloride. These molecular imprinting capsules are capable of recognizing higher quantities of protein than the existing technologies developed until now, with a simple formulation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325802 Exemplaires
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Titre : Dispersion of phosphonic acids surface - modified titania nanocrystals in various organic solvents Type de document : texte imprimé Auteurs : Toshihiko Arita, Auteur ; Ken-ichi Moriya, Auteur ; Tomoka Yoshimura, Auteur Année de publication : 2011 Article en page(s) : pp. 9815-9821 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Organic solvent Nanocrystal Dispersion Résumé : Titanium dioxide (TiO2, anatase) nanocyrstals tha can be transparently (perfectly) dispersed in several organic solvents were synthesized by organic-ligand-assisted hydrothermal synthesis. To analyze the dispersion behavior of surface-modified nanocrystals from the surface of the surface-modified nanocrystals, three types of surface-modified TiO2 nanocrystals were prepared. Depending on the surface nature of the surface-modified TiO2 nanocrystals, the nanocrystals showed different dispersion behaviors in organic solvents. In particular, the dispersion of surface-modified TiO2 nanocrystals with carboxylic acid terminated surface modifier (TiO2-COOH) varied strongly with changing solvent species. We investigated the dispersity of TiO2-COOH in typical organic solvents using dynamic light scattering (DLS) measurements. One of the three-dimensional solubility parameters, namely, the Hansen solubility parameter, provided detailed information on the mechanism of the dispersion of TiO2-COOH. Because of the carboxylic acid groups exhibited on the surface of the titania nanocrystals, the dispersion of TiO2-COOH was very much affected by the hydrogen-bonding ability of the solvent. The hydrogen-donating/-accepting ability adequately described the dispersion of TiO2-COOH in organic solvents. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325803
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9815-9821[article] Dispersion of phosphonic acids surface - modified titania nanocrystals in various organic solvents [texte imprimé] / Toshihiko Arita, Auteur ; Ken-ichi Moriya, Auteur ; Tomoka Yoshimura, Auteur . - 2011 . - pp. 9815-9821.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9815-9821
Mots-clés : Organic solvent Nanocrystal Dispersion Résumé : Titanium dioxide (TiO2, anatase) nanocyrstals tha can be transparently (perfectly) dispersed in several organic solvents were synthesized by organic-ligand-assisted hydrothermal synthesis. To analyze the dispersion behavior of surface-modified nanocrystals from the surface of the surface-modified nanocrystals, three types of surface-modified TiO2 nanocrystals were prepared. Depending on the surface nature of the surface-modified TiO2 nanocrystals, the nanocrystals showed different dispersion behaviors in organic solvents. In particular, the dispersion of surface-modified TiO2 nanocrystals with carboxylic acid terminated surface modifier (TiO2-COOH) varied strongly with changing solvent species. We investigated the dispersity of TiO2-COOH in typical organic solvents using dynamic light scattering (DLS) measurements. One of the three-dimensional solubility parameters, namely, the Hansen solubility parameter, provided detailed information on the mechanism of the dispersion of TiO2-COOH. Because of the carboxylic acid groups exhibited on the surface of the titania nanocrystals, the dispersion of TiO2-COOH was very much affected by the hydrogen-bonding ability of the solvent. The hydrogen-donating/-accepting ability adequately described the dispersion of TiO2-COOH in organic solvents. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325803 Exemplaires
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Titre : Steam - chest molding of expanded polypropylene foams : 1. DSC simulation of bead foam processing Type de document : texte imprimé Auteurs : Wentao Zhai, Auteur ; Young-Wook Kim, Auteur ; Chul B. Park, Auteur Année de publication : 2011 Article en page(s) : pp. 9822-9829 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Differential scanning calorimetry Foam Molding Water vapor Résumé : To investigate the evolution of melting behavior during the steam-chest molding process of expanded polypropylene (EPP) bead, a differential scanning calorimetry (DSC) test involving fast heating, isothermal treatment, and fast cooling was used to simulate the bead foam processing. The EPP bead foam had two original melting peaks: a low melting peak, Tmlow, and a high melting peak, Tmhigh. A new melting peak, Tmi, was induced in the DSC curves, resulting from the heating process, when the treatment temperature was 80—150 °C. The Tmi was about 7 °C higher than the treatment temperature and tended to increase linearly with the increased treatment temperature. A new melting area and further a melting peak, Tmc, were observed in DSC curves, resulting from the cooling process, when the treatment temperatures were higher than 135 °C. The high sensitivity of the Tmi and Tmc to treatment temperature provided a clue to the actual temperature inside the mold during the steam-chest molding process. Different steam pressures were applied during EPP bead processing, and the melting behavior of molded EPP samples was measured to check the processing thermal history. A comparison study was done between the DSC simulations and the actual results to understand the melting behavior evolution of EPP bead foam during processing. Some fundamental issues in the steam-chest molding processing, such as the actual steam temperature, the temperature gradient across the mold cavity, and the accurate pressure parameter used to describe the actual processing temperature were alsc studied based on the DSC simulation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325804
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9822-9829[article] Steam - chest molding of expanded polypropylene foams : 1. DSC simulation of bead foam processing [texte imprimé] / Wentao Zhai, Auteur ; Young-Wook Kim, Auteur ; Chul B. Park, Auteur . - 2011 . - pp. 9822-9829.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9822-9829
Mots-clés : Differential scanning calorimetry Foam Molding Water vapor Résumé : To investigate the evolution of melting behavior during the steam-chest molding process of expanded polypropylene (EPP) bead, a differential scanning calorimetry (DSC) test involving fast heating, isothermal treatment, and fast cooling was used to simulate the bead foam processing. The EPP bead foam had two original melting peaks: a low melting peak, Tmlow, and a high melting peak, Tmhigh. A new melting peak, Tmi, was induced in the DSC curves, resulting from the heating process, when the treatment temperature was 80—150 °C. The Tmi was about 7 °C higher than the treatment temperature and tended to increase linearly with the increased treatment temperature. A new melting area and further a melting peak, Tmc, were observed in DSC curves, resulting from the cooling process, when the treatment temperatures were higher than 135 °C. The high sensitivity of the Tmi and Tmc to treatment temperature provided a clue to the actual temperature inside the mold during the steam-chest molding process. Different steam pressures were applied during EPP bead processing, and the melting behavior of molded EPP samples was measured to check the processing thermal history. A comparison study was done between the DSC simulations and the actual results to understand the melting behavior evolution of EPP bead foam during processing. Some fundamental issues in the steam-chest molding processing, such as the actual steam temperature, the temperature gradient across the mold cavity, and the accurate pressure parameter used to describe the actual processing temperature were alsc studied based on the DSC simulation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325804 Exemplaires
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Titre : Optical properties of red algae fibers Type de document : texte imprimé Auteurs : Yung Bum Seo, Auteur ; Youn Woo Lee, Auteur ; Chun Han Lee, Auteur Année de publication : 2011 Article en page(s) : pp. 9830–9833 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Red algae fibers Résumé : Red algae fibers extracted from red algae (seaweed) showed very high opacity when used in the manufacture of white paper. For a basis weight of 60 g/m2, over 90% opacity was observed in paper made from red algae fibers without the aid of mineral fillers, whereas papers made from wood fibers had 70−80% opacity. Mercury porosimetry and light reflectance measurements at various wavelengths were used to investigate the origin of such high opacities in red algae fibers. The results revealed that red algae fibers had an extraordinarily high specific surface area on account of their very narrow widths (2−4 μm) and short lengths (500−800 μm). This unique property of red algae fibers can be best utilized for manufacturing highly opaque, premium-grade, lightweight printing papers without lowering the paper strength properties. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101194g
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9830–9833[article] Optical properties of red algae fibers [texte imprimé] / Yung Bum Seo, Auteur ; Youn Woo Lee, Auteur ; Chun Han Lee, Auteur . - 2011 . - pp. 9830–9833.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9830–9833
Mots-clés : Red algae fibers Résumé : Red algae fibers extracted from red algae (seaweed) showed very high opacity when used in the manufacture of white paper. For a basis weight of 60 g/m2, over 90% opacity was observed in paper made from red algae fibers without the aid of mineral fillers, whereas papers made from wood fibers had 70−80% opacity. Mercury porosimetry and light reflectance measurements at various wavelengths were used to investigate the origin of such high opacities in red algae fibers. The results revealed that red algae fibers had an extraordinarily high specific surface area on account of their very narrow widths (2−4 μm) and short lengths (500−800 μm). This unique property of red algae fibers can be best utilized for manufacturing highly opaque, premium-grade, lightweight printing papers without lowering the paper strength properties. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101194g Exemplaires
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Titre : Cell structure evolution and the crystallization behavior of polypropylene / clay nanocomposites foams blown in continuous extrusion Type de document : texte imprimé Auteurs : Wentao Zhai, Auteur ; Takashi Kuboki, Auteur ; Lilac Wang, Auteur Année de publication : 2011 Article en page(s) : pp. 9834–9845 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Crystallization Nanocomposites Résumé : In this study, linear homopolypropylene/clay (HPPC) nanocomposite foams with a high expansion ratio of about 18 and a high cell density of about 1.7 × 108 cells/cm3 were produced using an extrusion foaming method with CO2 as the physical blowing agent. The result was much better than pure HPP foams with expansion ratios of 1.7−2.2 and cell densities of 103−105 cells/cm3 obtained even at the same foaming conditions. The nanoclays had a half-exfoliated structure in the HPP matrix, and their presence dramatically affected the viscoelastic properties of HPP melt and foaming behaviors. It was found that the introduction of a small amount of nanoclay significantly increased the cell morphology of HPP foams at low die temperatures, where the cell wall was very thin and cell distribution was uniform. With an increase in nanoclay content of up to 5 wt %, cell morphology was improved gradually at broader die temperatures. Based on the cell morphology results, a suitable foaming window for clay content and die temperature was established. The mechanisms behind these phenomena are discussed from the perspective of cell nucleation and coalescence. Microstructures were found in the cell walls of HPP and HPPC nanocomposite foams, and they tended to evolve with cell wall thickness, depending on the die temperatures. Scanning electron microscopy (SEM) observation of foams and solvent-etched foams revealed that the microstructures in the cell walls were formed by covering large-sized crystals and that the absence of microstructures was due to the presence of small-sized crystals in the cell walls. A distribution of crystal sizes was observed across the foamed samples, which was affected by the die temperature and the introduction of nanoclay. The possible reasons were elaborated by considerations of temperature gradient. DSC tests indicated that the foaming process induced a low-temperature peak (Tm1) and its heat of fusion (ΔHm1) tended to evolve with the die temperature and the introduction of nanoclay. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101225f
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9834–9845[article] Cell structure evolution and the crystallization behavior of polypropylene / clay nanocomposites foams blown in continuous extrusion [texte imprimé] / Wentao Zhai, Auteur ; Takashi Kuboki, Auteur ; Lilac Wang, Auteur . - 2011 . - pp. 9834–9845.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9834–9845
Mots-clés : Crystallization Nanocomposites Résumé : In this study, linear homopolypropylene/clay (HPPC) nanocomposite foams with a high expansion ratio of about 18 and a high cell density of about 1.7 × 108 cells/cm3 were produced using an extrusion foaming method with CO2 as the physical blowing agent. The result was much better than pure HPP foams with expansion ratios of 1.7−2.2 and cell densities of 103−105 cells/cm3 obtained even at the same foaming conditions. The nanoclays had a half-exfoliated structure in the HPP matrix, and their presence dramatically affected the viscoelastic properties of HPP melt and foaming behaviors. It was found that the introduction of a small amount of nanoclay significantly increased the cell morphology of HPP foams at low die temperatures, where the cell wall was very thin and cell distribution was uniform. With an increase in nanoclay content of up to 5 wt %, cell morphology was improved gradually at broader die temperatures. Based on the cell morphology results, a suitable foaming window for clay content and die temperature was established. The mechanisms behind these phenomena are discussed from the perspective of cell nucleation and coalescence. Microstructures were found in the cell walls of HPP and HPPC nanocomposite foams, and they tended to evolve with cell wall thickness, depending on the die temperatures. Scanning electron microscopy (SEM) observation of foams and solvent-etched foams revealed that the microstructures in the cell walls were formed by covering large-sized crystals and that the absence of microstructures was due to the presence of small-sized crystals in the cell walls. A distribution of crystal sizes was observed across the foamed samples, which was affected by the die temperature and the introduction of nanoclay. The possible reasons were elaborated by considerations of temperature gradient. DSC tests indicated that the foaming process induced a low-temperature peak (Tm1) and its heat of fusion (ΔHm1) tended to evolve with the die temperature and the introduction of nanoclay. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101225f Exemplaires
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Titre : Development of a new inorganic−organic hybrid ion - exchanger of zirconium (IV) − propanolamine for efficient removal of fluoride from drinking water Type de document : texte imprimé Auteurs : S. K. Swain, Auteur ; Sulagna Mishra, Auteur ; Prachi Sharma, Auteur Année de publication : 2011 Article en page(s) : pp. 9846–9856 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hybrid Ion exchanger Résumé : This investigation reports the synthesis of a new adsorbent material (ZrPA), from Zr(IV) and propanolamine (PA), synthesized by sol−gel technique at room temperature following the green chemistry principle. The suitability of ZrPA as a potential adsorbent is assessed for the removal of fluoride following the batch mode of operation. The isotherm, kinetics, and thermodynamics of fluoride adsorption on ZrPA have been studied at various experimental conditions (initial fluoride concentration, adsorption time, adsorbent dose, and temperature). The characteristic of the adsorbent, before and after fluoride adsorption, was examined using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), coupled with energy dispersive spectrum (EDS) techniques. Further measurement of surface area, pore volume, and pore diameter using N2 intrusion automated gas sorption system shows the microporous nature of the prepared material. Adsorption of fluoride was found to be strongly affected by pH. Mathematically, pseudosecond-order kinetic model was found to best describe the reaction rate, which was consistent with the actual measurement. Applications of Freundlich, Langmuir, Temkin, and Dubinin−Radushkevich (D−R) isotherm models for the adsorption process were evaluated, and the data were also compared for six different error functions, that is, the sum of the squares of errors (SSE), sum of the absolute errors (SAE), the average relative error (ARE), the hybrid fractional error function (HYBRID), the Marquardt’s percent standard deviation (MPSD), and regression coefficient (R2), to test the adequacy and accuracy of the model equations. Thermodynamic parameters such as enthalpy, entropy, and free energy were calculated using van’t Hoff equations, which shows that fluoride adsorption on ZrPA indicates the spontaneous and endothermic nature of adsorption. The reusability of the ZrPA adsorbent material was tested up to 10 consecutive cycles for a sustainable commercial application purpose. Quantitative desorption of fluoride from ZrPA was found to be more than 95% at pH 12. To test the efficacy, the performance of the adsorbent material was studied with water samples collected from a fluorosis endemic region. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1012536
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9846–9856[article] Development of a new inorganic−organic hybrid ion - exchanger of zirconium (IV) − propanolamine for efficient removal of fluoride from drinking water [texte imprimé] / S. K. Swain, Auteur ; Sulagna Mishra, Auteur ; Prachi Sharma, Auteur . - 2011 . - pp. 9846–9856.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9846–9856
Mots-clés : Hybrid Ion exchanger Résumé : This investigation reports the synthesis of a new adsorbent material (ZrPA), from Zr(IV) and propanolamine (PA), synthesized by sol−gel technique at room temperature following the green chemistry principle. The suitability of ZrPA as a potential adsorbent is assessed for the removal of fluoride following the batch mode of operation. The isotherm, kinetics, and thermodynamics of fluoride adsorption on ZrPA have been studied at various experimental conditions (initial fluoride concentration, adsorption time, adsorbent dose, and temperature). The characteristic of the adsorbent, before and after fluoride adsorption, was examined using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), coupled with energy dispersive spectrum (EDS) techniques. Further measurement of surface area, pore volume, and pore diameter using N2 intrusion automated gas sorption system shows the microporous nature of the prepared material. Adsorption of fluoride was found to be strongly affected by pH. Mathematically, pseudosecond-order kinetic model was found to best describe the reaction rate, which was consistent with the actual measurement. Applications of Freundlich, Langmuir, Temkin, and Dubinin−Radushkevich (D−R) isotherm models for the adsorption process were evaluated, and the data were also compared for six different error functions, that is, the sum of the squares of errors (SSE), sum of the absolute errors (SAE), the average relative error (ARE), the hybrid fractional error function (HYBRID), the Marquardt’s percent standard deviation (MPSD), and regression coefficient (R2), to test the adequacy and accuracy of the model equations. Thermodynamic parameters such as enthalpy, entropy, and free energy were calculated using van’t Hoff equations, which shows that fluoride adsorption on ZrPA indicates the spontaneous and endothermic nature of adsorption. The reusability of the ZrPA adsorbent material was tested up to 10 consecutive cycles for a sustainable commercial application purpose. Quantitative desorption of fluoride from ZrPA was found to be more than 95% at pH 12. To test the efficacy, the performance of the adsorbent material was studied with water samples collected from a fluorosis endemic region. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1012536 Exemplaires
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Titre : Preparation of hydroxyaptite nanoparticles by using high - gravity reactive precipitation combined with hydrothermal method Type de document : texte imprimé Auteurs : Qing Yang, Auteur ; Jie-Xin Wang, Auteur ; Fen Guo, Auteur Année de publication : 2011 Article en page(s) : pp. 9857–9863 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydroxyaptite Nanoparticles Hydrothermal Résumé : Hydroxyapatite (HAP) nanoparticles were successfully prepared without using organic modifiers by the combination of high-gravity reactive precipitation and hydrothermal method. The influences of the high-gravity level, the total reactant flow rate, the reactant flow rate ratio, and the reactant concentration on the preparation of HAP nanoparticles were systematically explored. The results showed that a high-gravity level of 3808−7774 m/s2, a total reactant flow rate of 120−360 mL/min, a moderate reactant flow rate ratio of 0.6−1.67, and a low reactant concentration of 0.04−0.3 mol/L favored the formation of uniformly small HAP nanoparticles with a mean size of 55−110 nm and a narrow size distribution. The increase of the high-gravity level led to the initial rapid and following slight decrease of the mean particle size. The mean particle size first decreased and subsequently increased with increasing the total reactant flow rate, the reactant flow rate ratio, and the reactant concentration. The uniformity of HAP nanoparticles was mainly determined by the micromixing condition of reactants. It could be envisioned that high-gravity reactive precipitation combined with hydrothermal method would be promising in the commercial production of HAP nanoparticles. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1012757
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9857–9863[article] Preparation of hydroxyaptite nanoparticles by using high - gravity reactive precipitation combined with hydrothermal method [texte imprimé] / Qing Yang, Auteur ; Jie-Xin Wang, Auteur ; Fen Guo, Auteur . - 2011 . - pp. 9857–9863.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9857–9863
Mots-clés : Hydroxyaptite Nanoparticles Hydrothermal Résumé : Hydroxyapatite (HAP) nanoparticles were successfully prepared without using organic modifiers by the combination of high-gravity reactive precipitation and hydrothermal method. The influences of the high-gravity level, the total reactant flow rate, the reactant flow rate ratio, and the reactant concentration on the preparation of HAP nanoparticles were systematically explored. The results showed that a high-gravity level of 3808−7774 m/s2, a total reactant flow rate of 120−360 mL/min, a moderate reactant flow rate ratio of 0.6−1.67, and a low reactant concentration of 0.04−0.3 mol/L favored the formation of uniformly small HAP nanoparticles with a mean size of 55−110 nm and a narrow size distribution. The increase of the high-gravity level led to the initial rapid and following slight decrease of the mean particle size. The mean particle size first decreased and subsequently increased with increasing the total reactant flow rate, the reactant flow rate ratio, and the reactant concentration. The uniformity of HAP nanoparticles was mainly determined by the micromixing condition of reactants. It could be envisioned that high-gravity reactive precipitation combined with hydrothermal method would be promising in the commercial production of HAP nanoparticles. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1012757 Exemplaires
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Titre : Trimethyl borate regenerated from spent sodium borohydride after hydrogen production Type de document : texte imprimé Auteurs : Cheng-Hong Liu, Auteur ; Bing-Hung Chen, Auteur ; Duu-Jong Lee, Auteur Année de publication : 2011 Article en page(s) : pp. 9864–9869 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydrogen production Résumé : Sodium metaborate (NaBO2) is the hydrolysate of sodium borohydride (NaBH4) for hydrogen production. Trimethyl borate (B(OCH3)3), the major reactant for producing sodium borohydride via the Brown−Schlesinger process, is successfully regenerated from sodium metaborate (NaBO2) via a sequential process including reacting with sulfuric acid, cooling crystallization, and reactive esterification distillation. The metaborate is first converted to boric acid (H3BO3) by reacting with sulfuric acid, bypassing formation of borax (Na2B4O7·10H2O) required in a conventional process. Cooling crystallization is utilized to separate and purify boric acid from coexisting sodium sulfate (Na2SO4). Subsequently, trimethyl borate is formed via esterification of boric acid with methanol, in which reactive esterification distillation is adopted to facilitate the esterification and purify the product. Formation of boric acid and trimethyl borate is confirmed with X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FT-IR), and gas chromatography (GC). Approximately 55% of sodium metaborate could be converted to boric acid, along with a production yield from 74.1% to 96.5% realized for trimethyl borate esterified from the as-produced boric acid. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325809
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9864–9869[article] Trimethyl borate regenerated from spent sodium borohydride after hydrogen production [texte imprimé] / Cheng-Hong Liu, Auteur ; Bing-Hung Chen, Auteur ; Duu-Jong Lee, Auteur . - 2011 . - pp. 9864–9869.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9864–9869
Mots-clés : Hydrogen production Résumé : Sodium metaborate (NaBO2) is the hydrolysate of sodium borohydride (NaBH4) for hydrogen production. Trimethyl borate (B(OCH3)3), the major reactant for producing sodium borohydride via the Brown−Schlesinger process, is successfully regenerated from sodium metaborate (NaBO2) via a sequential process including reacting with sulfuric acid, cooling crystallization, and reactive esterification distillation. The metaborate is first converted to boric acid (H3BO3) by reacting with sulfuric acid, bypassing formation of borax (Na2B4O7·10H2O) required in a conventional process. Cooling crystallization is utilized to separate and purify boric acid from coexisting sodium sulfate (Na2SO4). Subsequently, trimethyl borate is formed via esterification of boric acid with methanol, in which reactive esterification distillation is adopted to facilitate the esterification and purify the product. Formation of boric acid and trimethyl borate is confirmed with X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FT-IR), and gas chromatography (GC). Approximately 55% of sodium metaborate could be converted to boric acid, along with a production yield from 74.1% to 96.5% realized for trimethyl borate esterified from the as-produced boric acid. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325809 Exemplaires
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Titre : Miscibility and crystallization behaviors of poly (butylene succinate) and poly (l-lactic acid) segments in their multiblock copoly (ester urethane) Type de document : texte imprimé Auteurs : Jian-Bing Zeng, Auteur ; Cong Liu, Auteur ; Fang-Yang Liu, Auteur Année de publication : 2011 Article en page(s) : pp. 9870–9876 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Crystallization Résumé : Miscibility and crystallization behaviors of poly(butylenes succinate) (PBS) and poly(l-lactic acid) (PLLA) segments in their multiblock copoly(ester urethane) were investigated by differential scanning calorimetry (DSC), polarized optical microscopy (POM), and wide-angle X-ray diffraction (WAXD). The single glass transition and depressed crystallization temperatures of PEUs with different compositions suggest that PBS and PLLA segments are miscible in amorphous phase of PEUs. Nonisothermal crystallization kinetics of PEUs was studied by Avrami and Mo methods; both results suggest that the crystallization rates of PEUs decreased with increasing weight fraction of PLLA segments. POM results indicate that banded spherulites were formed for PEUs when PLLA segments were introduced, and the band spacing increased with weight fraction of PLLA segments. The investigation of WAXD demonstrated the crystal structure of PEUs was the same as that of PBS, suggesting the crystallization of PEUs arose from PBS segments, and PLLA segments were unable to crystallize in PEUs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325810
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9870–9876[article] Miscibility and crystallization behaviors of poly (butylene succinate) and poly (l-lactic acid) segments in their multiblock copoly (ester urethane) [texte imprimé] / Jian-Bing Zeng, Auteur ; Cong Liu, Auteur ; Fang-Yang Liu, Auteur . - 2011 . - pp. 9870–9876.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9870–9876
Mots-clés : Crystallization Résumé : Miscibility and crystallization behaviors of poly(butylenes succinate) (PBS) and poly(l-lactic acid) (PLLA) segments in their multiblock copoly(ester urethane) were investigated by differential scanning calorimetry (DSC), polarized optical microscopy (POM), and wide-angle X-ray diffraction (WAXD). The single glass transition and depressed crystallization temperatures of PEUs with different compositions suggest that PBS and PLLA segments are miscible in amorphous phase of PEUs. Nonisothermal crystallization kinetics of PEUs was studied by Avrami and Mo methods; both results suggest that the crystallization rates of PEUs decreased with increasing weight fraction of PLLA segments. POM results indicate that banded spherulites were formed for PEUs when PLLA segments were introduced, and the band spacing increased with weight fraction of PLLA segments. The investigation of WAXD demonstrated the crystal structure of PEUs was the same as that of PBS, suggesting the crystallization of PEUs arose from PBS segments, and PLLA segments were unable to crystallize in PEUs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325810 Exemplaires
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Titre : Design methodology for screening dynamic characteristics of candidate heat - integrated flowsheets Type de document : texte imprimé Auteurs : Robert J. Brende, Auteur ; Prasad S. Dhurjati, Auteur Année de publication : 2011 Article en page(s) : pp. 9877–9886 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Heat integrated Dynamic Résumé : Well-established design methods exist for generating candidate heat-exchanger networks (HENs), but there is a strong need for a methodology to screen for undesirable dynamic characteristics that are often observed in heat-integrated processes. In this paper, a simple transfer function-based method is developed that can assist in comparing dynamic behavior of candidate heat-integrated flowsheets. Use of the method allows the design engineer to determine the dynamic characteristics of the overall process shortly after identifying exchanger networks that satisfy the process heat balance. Mathematical development of the method is given, followed by explanations of its use. The basis of the method is developed in block-diagram format, making apparent the source of positive feedback that can result from adding heat integration to a process. Finally, the method is demonstrated on three candidate HENs for a simple process. The method allows for identification of dynamic characteristics that would not be determined through steady-state analysis alone. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901399f
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9877–9886[article] Design methodology for screening dynamic characteristics of candidate heat - integrated flowsheets [texte imprimé] / Robert J. Brende, Auteur ; Prasad S. Dhurjati, Auteur . - 2011 . - pp. 9877–9886.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9877–9886
Mots-clés : Heat integrated Dynamic Résumé : Well-established design methods exist for generating candidate heat-exchanger networks (HENs), but there is a strong need for a methodology to screen for undesirable dynamic characteristics that are often observed in heat-integrated processes. In this paper, a simple transfer function-based method is developed that can assist in comparing dynamic behavior of candidate heat-integrated flowsheets. Use of the method allows the design engineer to determine the dynamic characteristics of the overall process shortly after identifying exchanger networks that satisfy the process heat balance. Mathematical development of the method is given, followed by explanations of its use. The basis of the method is developed in block-diagram format, making apparent the source of positive feedback that can result from adding heat integration to a process. Finally, the method is demonstrated on three candidate HENs for a simple process. The method allows for identification of dynamic characteristics that would not be determined through steady-state analysis alone. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901399f Exemplaires
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Titre : Reduction of a urea crystallizer model by proper orthogonal decomposition and best - points interpolation Type de document : texte imprimé Auteurs : Mykhaylo Krasnyk, Auteur ; Michael Mangold, Auteur Année de publication : 2011 Article en page(s) : pp. 9887–9898 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Modeling Cristalliseur Résumé : A reduced model of a urea crystallizer is developed for process control purposes. It is derived from a reference model, which describes the formation of particles in fluid flow and is of very high order. A strong reduction of the system order is achieved by proper orthogonal decomposition (POD). However, it turns out that POD alone does not lead to a satisfactory reduction of the computation time. The reason is the presence of nonlinear terms in the reference model whose evaluation is quite costly in the reduced model. To get a speed-up of the reduced model, the nonlinear terms are approximated by an interpolation technique. The resulting reduced model is 500 times smaller and 100 times faster than the reference model, while the loss of accuracy is marginal. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325812
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9887–9898[article] Reduction of a urea crystallizer model by proper orthogonal decomposition and best - points interpolation [texte imprimé] / Mykhaylo Krasnyk, Auteur ; Michael Mangold, Auteur . - 2011 . - pp. 9887–9898.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9887–9898
Mots-clés : Modeling Cristalliseur Résumé : A reduced model of a urea crystallizer is developed for process control purposes. It is derived from a reference model, which describes the formation of particles in fluid flow and is of very high order. A strong reduction of the system order is achieved by proper orthogonal decomposition (POD). However, it turns out that POD alone does not lead to a satisfactory reduction of the computation time. The reason is the presence of nonlinear terms in the reference model whose evaluation is quite costly in the reduced model. To get a speed-up of the reduced model, the nonlinear terms are approximated by an interpolation technique. The resulting reduced model is 500 times smaller and 100 times faster than the reference model, while the loss of accuracy is marginal. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325812 Exemplaires
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Titre : Automated targeting technique for batch process integration Type de document : texte imprimé Auteurs : Dominic Chwan Yee Foo, Auteur Année de publication : 2011 Article en page(s) : pp. 9899–9916 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Targeting Batch process Résumé : A new targeting technique is proposed in this work to determine the minimum resource and waste targets for batch process integration problems. The technique, which is generic in nature, handles fixed-schedule batch heat and mass exchange, as well as water networks equally well. Even though the technique is formulated as a mathematical optimization model, the concept, which is built on the insight-based pinch analysis technique, enables the minimum resource/cost targets to be identified prior to detailed design. Five examples are solved to demonstrate the newly developed technique. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100146n
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9899–9916[article] Automated targeting technique for batch process integration [texte imprimé] / Dominic Chwan Yee Foo, Auteur . - 2011 . - pp. 9899–9916.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9899–9916
Mots-clés : Targeting Batch process Résumé : A new targeting technique is proposed in this work to determine the minimum resource and waste targets for batch process integration problems. The technique, which is generic in nature, handles fixed-schedule batch heat and mass exchange, as well as water networks equally well. Even though the technique is formulated as a mathematical optimization model, the concept, which is built on the insight-based pinch analysis technique, enables the minimum resource/cost targets to be identified prior to detailed design. Five examples are solved to demonstrate the newly developed technique. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100146n Exemplaires
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Titre : Dynamic simulation and decision support for multisite specialty chemicals supply chain Type de document : texte imprimé Auteurs : Arief Adhitya, Auteur ; Rajagopalan Srinivasan, Auteur Année de publication : 2011 Article en page(s) : pp. 9917-9931 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Modeling Dynamic model Résumé : Companies are increasingly shifting from single-site manufacturing to multisite operations to tap into the vast business opportunities offered by globalization. The supply chain of such a multisite enterprise is complex, involving numerous interacting entities with various roles and constraints, resulting in complex dynamics and complexities in decision making. This complexity motivates the development of simulation models of the supply chain that can capture the behavior of the entities, their interactions, the resulting dynamics, and the various uncertainties. In this article, we present a dynamic model of a multisitc specialty chemicals supply chain that can serve as a quantitative simulation and decision support tool. The model explicitly considers the different supply chain entities and their interactions across various activities such as order acceptance and assignment, job scheduling, raw material procurement, storage, and production. It has been implemented as a dynamic simulator in Matlab/Simulink, called the integrated lube additive supply chain simulator (ILAS). Different policies, configurations, and uncertainties can be simulated in ILAS, and their impacts on the overall performance of the supply chain, such as customer satisfaction and profit, can be analyzed. The capabilities of ILAS for decision support are illustrated using several case studies. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325814
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9917-9931[article] Dynamic simulation and decision support for multisite specialty chemicals supply chain [texte imprimé] / Arief Adhitya, Auteur ; Rajagopalan Srinivasan, Auteur . - 2011 . - pp. 9917-9931.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9917-9931
Mots-clés : Modeling Dynamic model Résumé : Companies are increasingly shifting from single-site manufacturing to multisite operations to tap into the vast business opportunities offered by globalization. The supply chain of such a multisite enterprise is complex, involving numerous interacting entities with various roles and constraints, resulting in complex dynamics and complexities in decision making. This complexity motivates the development of simulation models of the supply chain that can capture the behavior of the entities, their interactions, the resulting dynamics, and the various uncertainties. In this article, we present a dynamic model of a multisitc specialty chemicals supply chain that can serve as a quantitative simulation and decision support tool. The model explicitly considers the different supply chain entities and their interactions across various activities such as order acceptance and assignment, job scheduling, raw material procurement, storage, and production. It has been implemented as a dynamic simulator in Matlab/Simulink, called the integrated lube additive supply chain simulator (ILAS). Different policies, configurations, and uncertainties can be simulated in ILAS, and their impacts on the overall performance of the supply chain, such as customer satisfaction and profit, can be analyzed. The capabilities of ILAS for decision support are illustrated using several case studies. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325814 Exemplaires
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Titre : Histogram matching, hypothesis testing, and statistical control - chart - assisted nucleation detection using bulk video imaging for optimal switching between nucleation and seed conditioning steps Type de document : texte imprimé Auteurs : Levente L. Simon, Auteur ; Kaoutar Abbou Oucherif, Auteur ; Zoltan K. Nagy, Auteur Année de publication : 2011 Article en page(s) : pp. 9932-9944 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Conditioning Imaging Résumé : This article investigates the systematic nucleation detection performance of hypothesis testing, histogram matching, and control charts based on bulk video imaging. The control charts are built on the time series of the bin-by-bin distances between the reference and online acquired image histograms. In addition to the bin-by-bin histogram measures, the cross-bin earth mover's distance measure has been evaluated. Hypothesis testing using the Kolmogorov-Smirnof (KS) statistics was also investigated as an additional method to detect nucleation. This work is relevant to the crystallization process control with in situ seed generation. Following the nucleation step in unseeded crystallization processes, it is common to keep the temperature constant or to increase it in order to allow the stabilization of the suspension, also called the digestion step. The nucleation detection methods discussed in this work allow the automated and robust switching between the nucleation and digestion steps. It is concluded that histogram matching can be successfully used for systematic nucleation detection, while the KS hypothesis-testing-based detection is strongly dependent on the histogram resolution. Furthermore, it is suggested that histogram matching is performed on the first principal components of color images in order to decrease the autocorrelation of histogram distance time series. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325815
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9932-9944[article] Histogram matching, hypothesis testing, and statistical control - chart - assisted nucleation detection using bulk video imaging for optimal switching between nucleation and seed conditioning steps [texte imprimé] / Levente L. Simon, Auteur ; Kaoutar Abbou Oucherif, Auteur ; Zoltan K. Nagy, Auteur . - 2011 . - pp. 9932-9944.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9932-9944
Mots-clés : Conditioning Imaging Résumé : This article investigates the systematic nucleation detection performance of hypothesis testing, histogram matching, and control charts based on bulk video imaging. The control charts are built on the time series of the bin-by-bin distances between the reference and online acquired image histograms. In addition to the bin-by-bin histogram measures, the cross-bin earth mover's distance measure has been evaluated. Hypothesis testing using the Kolmogorov-Smirnof (KS) statistics was also investigated as an additional method to detect nucleation. This work is relevant to the crystallization process control with in situ seed generation. Following the nucleation step in unseeded crystallization processes, it is common to keep the temperature constant or to increase it in order to allow the stabilization of the suspension, also called the digestion step. The nucleation detection methods discussed in this work allow the automated and robust switching between the nucleation and digestion steps. It is concluded that histogram matching can be successfully used for systematic nucleation detection, while the KS hypothesis-testing-based detection is strongly dependent on the histogram resolution. Furthermore, it is suggested that histogram matching is performed on the first principal components of color images in order to decrease the autocorrelation of histogram distance time series. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325815 Exemplaires
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Titre : Water integration of eco - industrial parks using a global optimization approach Type de document : texte imprimé Auteurs : Eusiel Rubio-Castro, Auteur ; José María Ponce-Ortega, Auteur ; Fabricio Napoles-Rivera, Auteur Année de publication : 2011 Article en page(s) : pp. 9945-9960 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Optimization Résumé : This Article presents a mathematical programming model for the mass integration of eco-industrial parks. The model considers the reuse of wastewater among different industries and the constraints given by the process sinks and the environmental regulations for waste streams discharged to the environment. The model allows the optimal selection of treatment units to satisfy the process and environmental regulations. The objective function consists of the minimization of the total annual cost, including the treatment unit costs, the piping costs, and the cost of fresh water. A new discretization approach is proposed for the model reformulation to handle the bilinear terms of the model as part of a global optimization strategy. Results show that significant savings can be achieved for the design of an integrated eco-industrial park with respect to the integration of each individual industry. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325816
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9945-9960[article] Water integration of eco - industrial parks using a global optimization approach [texte imprimé] / Eusiel Rubio-Castro, Auteur ; José María Ponce-Ortega, Auteur ; Fabricio Napoles-Rivera, Auteur . - 2011 . - pp. 9945-9960.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9945-9960
Mots-clés : Optimization Résumé : This Article presents a mathematical programming model for the mass integration of eco-industrial parks. The model considers the reuse of wastewater among different industries and the constraints given by the process sinks and the environmental regulations for waste streams discharged to the environment. The model allows the optimal selection of treatment units to satisfy the process and environmental regulations. The objective function consists of the minimization of the total annual cost, including the treatment unit costs, the piping costs, and the cost of fresh water. A new discretization approach is proposed for the model reformulation to handle the bilinear terms of the model as part of a global optimization strategy. Results show that significant savings can be achieved for the design of an integrated eco-industrial park with respect to the integration of each individual industry. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325816 Exemplaires
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Titre : Statistical monitoring and fault diagnosis of batch processes using two - dimensional dynamic information Type de document : texte imprimé Auteurs : Yuan Yao, Auteur ; Furong Gao, Auteur Année de publication : 2011 Article en page(s) : pp. 9961–9969 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Dynamic Résumé : Two-dimensional (2D) dynamics widely exist in batch processes, which inspirit research efforts to develop corresponding monitoring schemes. Recently, two-dimensional dynamic principal component analysis (2D-DPCA) has been proposed to model and monitor such 2D dynamic batch processes, in which support region (ROS) determination is a key step. A proper ROS ensures modeling accuracy, monitoring efficiency, and reasonable fault diagnosis. The previous ROS determination method is practicable in many situations but still has certain limitations, as discussed in this paper. To overcome these shortcomings, a 2D-DPCA method with an improved ROS determination procedure is developed, by considering variable partial correlations and performing iterative stepwise regressions. Such a procedure expands ROS batch by batch and is a generalization of the autoregressive (AR) model order selection to the 2D batch process cases. Simulations show that the proposed method extracts 2D dynamics more accurately and improves the monitoring and diagnosis performance of the 2D-DPCA model. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100860x
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9961–9969[article] Statistical monitoring and fault diagnosis of batch processes using two - dimensional dynamic information [texte imprimé] / Yuan Yao, Auteur ; Furong Gao, Auteur . - 2011 . - pp. 9961–9969.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9961–9969
Mots-clés : Dynamic Résumé : Two-dimensional (2D) dynamics widely exist in batch processes, which inspirit research efforts to develop corresponding monitoring schemes. Recently, two-dimensional dynamic principal component analysis (2D-DPCA) has been proposed to model and monitor such 2D dynamic batch processes, in which support region (ROS) determination is a key step. A proper ROS ensures modeling accuracy, monitoring efficiency, and reasonable fault diagnosis. The previous ROS determination method is practicable in many situations but still has certain limitations, as discussed in this paper. To overcome these shortcomings, a 2D-DPCA method with an improved ROS determination procedure is developed, by considering variable partial correlations and performing iterative stepwise regressions. Such a procedure expands ROS batch by batch and is a generalization of the autoregressive (AR) model order selection to the 2D batch process cases. Simulations show that the proposed method extracts 2D dynamics more accurately and improves the monitoring and diagnosis performance of the 2D-DPCA model. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100860x Exemplaires
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Titre : Strategic planning of integrated multirefinery networks : A robust optimization approach based on the degree of conservatism Type de document : texte imprimé Auteurs : Adriana Leiras, Auteur ; Ali Elkamel, Auteur ; Silvio Hamacher, Auteur Année de publication : 2011 Article en page(s) : pp. 9970–9977 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Optimization Résumé : This paper considers the problem of strategic planning under uncertainty for optimal integration and coordination of a multirefinery network. The deterministic model proposed by Al-Qahtani and Elkamel [Comput. Chem. Eng. 2008, 32, 2189−202] was extended to account for uncertainties in raw material costs and final product prices, as well as product demand. The robust optimization methodology of Bertsimas and Sim [Op. Res. 2004, 52, 35−53] was applied, which deals with uncertainty in a tractable manner and does not add complexity to the deterministic problem. An industrial-scale study illustrated the benefits of the integrated planning and demonstrated that the modeling of uncertainty in process parameters provides a more practical perspective of the refining industry. In addition, probability bounds of constraint violation were calculated to help decision makers select appropriate parameters to control solution robustness and evaluate trade-offs between conservatism and total profit. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100919z
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9970–9977[article] Strategic planning of integrated multirefinery networks : A robust optimization approach based on the degree of conservatism [texte imprimé] / Adriana Leiras, Auteur ; Ali Elkamel, Auteur ; Silvio Hamacher, Auteur . - 2011 . - pp. 9970–9977.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9970–9977
Mots-clés : Optimization Résumé : This paper considers the problem of strategic planning under uncertainty for optimal integration and coordination of a multirefinery network. The deterministic model proposed by Al-Qahtani and Elkamel [Comput. Chem. Eng. 2008, 32, 2189−202] was extended to account for uncertainties in raw material costs and final product prices, as well as product demand. The robust optimization methodology of Bertsimas and Sim [Op. Res. 2004, 52, 35−53] was applied, which deals with uncertainty in a tractable manner and does not add complexity to the deterministic problem. An industrial-scale study illustrated the benefits of the integrated planning and demonstrated that the modeling of uncertainty in process parameters provides a more practical perspective of the refining industry. In addition, probability bounds of constraint violation were calculated to help decision makers select appropriate parameters to control solution robustness and evaluate trade-offs between conservatism and total profit. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100919z Exemplaires
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Titre : Use of hybrid membrane cells to improve the apparent selectivity in the fractionation of two components : Computational fluid dynamics study Type de document : texte imprimé Auteurs : S. I. S. Pinto, Auteur ; J. M. Miranda, Auteur ; J. B. L. M. Campos, Auteur Année de publication : 2011 Article en page(s) : pp. 9978–9987 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hybrid Fluid dynamics Résumé : The fractionation of aqueous solutions of bovine serum albumin (BSA) and Dextran-T10 in a hybrid membrane cell is studied by numerical methods. The hybrid membrane cell has n semipermeable and n fully permeable membrane subsections alternating in series. The cell has a feed stream and three outlet streams: the retentate stream, a BSA-rich permeate stream, and a dextran-rich permeate stream. The flow and concentration fields of the solutes are determined by solving the Navier−Stokes and mass transport equations. The apparent selectivity of the separation process is determined from the concentrations of the solutes in the permeate streams. The selectivity of a hybrid membrane cell is compared with the selectivity of a conventional membrane cell. The selectivity is higher in the hybrid membrane cell due to the depolarization effect promoted by the fully permeable membranes. The difference is significant in the range of transmembrane pressure for which the membrane of the conventional cell becomes polarized. The selectivity of the hybrid membrane cell is maximized for high permeate velocities through the fully permeable membranes and high number of membrane sections. Additionally, the less transmitted component is preferentially recovered in the stream that crosses the fully permeable membranes. In comparison with conventional cells, the hybrid membrane cell has good performance along a large range of the transmembrane pressure, a characteristic that gives it good operational flexibility. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100152y
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9978–9987[article] Use of hybrid membrane cells to improve the apparent selectivity in the fractionation of two components : Computational fluid dynamics study [texte imprimé] / S. I. S. Pinto, Auteur ; J. M. Miranda, Auteur ; J. B. L. M. Campos, Auteur . - 2011 . - pp. 9978–9987.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9978–9987
Mots-clés : Hybrid Fluid dynamics Résumé : The fractionation of aqueous solutions of bovine serum albumin (BSA) and Dextran-T10 in a hybrid membrane cell is studied by numerical methods. The hybrid membrane cell has n semipermeable and n fully permeable membrane subsections alternating in series. The cell has a feed stream and three outlet streams: the retentate stream, a BSA-rich permeate stream, and a dextran-rich permeate stream. The flow and concentration fields of the solutes are determined by solving the Navier−Stokes and mass transport equations. The apparent selectivity of the separation process is determined from the concentrations of the solutes in the permeate streams. The selectivity of a hybrid membrane cell is compared with the selectivity of a conventional membrane cell. The selectivity is higher in the hybrid membrane cell due to the depolarization effect promoted by the fully permeable membranes. The difference is significant in the range of transmembrane pressure for which the membrane of the conventional cell becomes polarized. The selectivity of the hybrid membrane cell is maximized for high permeate velocities through the fully permeable membranes and high number of membrane sections. Additionally, the less transmitted component is preferentially recovered in the stream that crosses the fully permeable membranes. In comparison with conventional cells, the hybrid membrane cell has good performance along a large range of the transmembrane pressure, a characteristic that gives it good operational flexibility. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100152y Exemplaires
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Titre : Effect of polyethersulfone molecular weight on structure and performance of ultrafiltration membranes Type de document : texte imprimé Auteurs : Chen Zhou, Auteur ; Zhengchi Hou, Auteur ; Xiaofeng Lu, Auteur Année de publication : 2011 Article en page(s) : pp. 9988–9997 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Polyethersulfone molecular Résumé : Polyethersulfones (PES) with three different molecular weights were chosen to prepare ultrafiltration (UF) membranes by the nonsolvent induced phase separation method using polyvinylpyrrolidone (PVP) and N-methyl-2-pyrrolidone (NMP) as additive and solvent, respectively. The effect of PES molecular weight on the structure and performance of the prepared asymmetric membranes was investigated by means of UF experiments, measurements of membrane thickness and porosity, scanning electron microscopy, and the measurement of bursting strength, given fixed PVP or PES concentrations. It was found that increasing PES molecular weight would lead to a larger pore size in the skin layer but lower membrane porosity, and would result in membranes with higher strength, higher permeability, and lower rejection. Based on the experimental data of PES molecular weight, ternary phase diagram, and cast solution viscosity obtained from gel permeation chromatography, cloud point titration, and coaxial cylinder viscometer measurements, respectively, the underlying causes of membrane structures were accounted for from the combined perspective of thermodynamics and kinetics and polymer aggregate dimensions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100199h
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9988–9997[article] Effect of polyethersulfone molecular weight on structure and performance of ultrafiltration membranes [texte imprimé] / Chen Zhou, Auteur ; Zhengchi Hou, Auteur ; Xiaofeng Lu, Auteur . - 2011 . - pp. 9988–9997.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9988–9997
Mots-clés : Polyethersulfone molecular Résumé : Polyethersulfones (PES) with three different molecular weights were chosen to prepare ultrafiltration (UF) membranes by the nonsolvent induced phase separation method using polyvinylpyrrolidone (PVP) and N-methyl-2-pyrrolidone (NMP) as additive and solvent, respectively. The effect of PES molecular weight on the structure and performance of the prepared asymmetric membranes was investigated by means of UF experiments, measurements of membrane thickness and porosity, scanning electron microscopy, and the measurement of bursting strength, given fixed PVP or PES concentrations. It was found that increasing PES molecular weight would lead to a larger pore size in the skin layer but lower membrane porosity, and would result in membranes with higher strength, higher permeability, and lower rejection. Based on the experimental data of PES molecular weight, ternary phase diagram, and cast solution viscosity obtained from gel permeation chromatography, cloud point titration, and coaxial cylinder viscometer measurements, respectively, the underlying causes of membrane structures were accounted for from the combined perspective of thermodynamics and kinetics and polymer aggregate dimensions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100199h Exemplaires
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Titre : Removal of chromium(VI) from aqueous solutions using polyaniline doped with sulfuric acid Type de document : texte imprimé Auteurs : Runhu Zhang, Auteur ; Hongzhu Ma, Auteur ; Bo Wang, Auteur Année de publication : 2011 Article en page(s) : pp. 9998-10004 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Aqueous solution Résumé : A type of polyaniline was synthesized and its Cr (VI) removal potential was investigated in this work. The kinetics study, adsorption isotherm, pH effect, and thermodynamic study were examined in batch experiments. Adsorption data for Cr (VI) uptake by polyaniline were analyzed according to Langmuir and Freundlich adsorption models. Thermodynamic parameters for the adsorption system were determinated at 293 K, 303 K, and 313 K (ΔH° = 23.87 kJ mol-1; ΔG° = -10.76 to -13.13 kJ mol-1 and ΔS° = 118.20 J K-1 mol-1). The positive values of both ΔH° and ΔS° suggest an endothermic reaction, increasing in randomness at the solid—liquid interface during the adsorption process. ΔG° values obtained were negative, indicated that the adsorption of the Cr (VI) ion on the surface of polyaniline was a spontaneous adsorption process. The kinetics process can be described by a pseudosecond-order rate equation very well. The Cr (VI) adsorption capacity tended to increase with a decrease of pH. The maximum uptake of Cr (VI) was 95.79 mg g-1. These results show that the polyaniline doped with sulfuric acid could be considered as a potential adsorbent for chromium hexavalent ions in aqueous solutions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325821
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9998-10004[article] Removal of chromium(VI) from aqueous solutions using polyaniline doped with sulfuric acid [texte imprimé] / Runhu Zhang, Auteur ; Hongzhu Ma, Auteur ; Bo Wang, Auteur . - 2011 . - pp. 9998-10004.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9998-10004
Mots-clés : Aqueous solution Résumé : A type of polyaniline was synthesized and its Cr (VI) removal potential was investigated in this work. The kinetics study, adsorption isotherm, pH effect, and thermodynamic study were examined in batch experiments. Adsorption data for Cr (VI) uptake by polyaniline were analyzed according to Langmuir and Freundlich adsorption models. Thermodynamic parameters for the adsorption system were determinated at 293 K, 303 K, and 313 K (ΔH° = 23.87 kJ mol-1; ΔG° = -10.76 to -13.13 kJ mol-1 and ΔS° = 118.20 J K-1 mol-1). The positive values of both ΔH° and ΔS° suggest an endothermic reaction, increasing in randomness at the solid—liquid interface during the adsorption process. ΔG° values obtained were negative, indicated that the adsorption of the Cr (VI) ion on the surface of polyaniline was a spontaneous adsorption process. The kinetics process can be described by a pseudosecond-order rate equation very well. The Cr (VI) adsorption capacity tended to increase with a decrease of pH. The maximum uptake of Cr (VI) was 95.79 mg g-1. These results show that the polyaniline doped with sulfuric acid could be considered as a potential adsorbent for chromium hexavalent ions in aqueous solutions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325821 Exemplaires
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Titre : Extraction of germanium by the AOT microemulsion with N235 system Type de document : texte imprimé Auteurs : Fei Liu, Auteur ; Yanzhao Yang, Auteur ; Yanmin Lu, Auteur Année de publication : 2011 Article en page(s) : pp. 10005–10008 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Microemulsion Résumé : The extraction of germanium to a W/O microemulsion by the combination with an anionic surfactant and an amine extractant was studied. In the AOT/n-butanol/n-heptane/Na2SO4/N235 system, AOT was used as an anionic surfactant to form a microemulsion in n-heptane, n-butanol was injected in the microemulsion as a cosurfactant to enhance the stability, and N235 was a typical extractant in the system. The microemulsion system without N235 showed poor extractability and stability. However, by adding N235, the extraction efficiency (E%) can be more than 99%, and the stability of the microemulsion extremely enhanced. The influences of the concentration of cosurfactant, temperature, pH of the feed solution, and composition of the feed solution on the extraction efficiency (E%) were verified. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100963t
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10005–10008[article] Extraction of germanium by the AOT microemulsion with N235 system [texte imprimé] / Fei Liu, Auteur ; Yanzhao Yang, Auteur ; Yanmin Lu, Auteur . - 2011 . - pp. 10005–10008.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10005–10008
Mots-clés : Microemulsion Résumé : The extraction of germanium to a W/O microemulsion by the combination with an anionic surfactant and an amine extractant was studied. In the AOT/n-butanol/n-heptane/Na2SO4/N235 system, AOT was used as an anionic surfactant to form a microemulsion in n-heptane, n-butanol was injected in the microemulsion as a cosurfactant to enhance the stability, and N235 was a typical extractant in the system. The microemulsion system without N235 showed poor extractability and stability. However, by adding N235, the extraction efficiency (E%) can be more than 99%, and the stability of the microemulsion extremely enhanced. The influences of the concentration of cosurfactant, temperature, pH of the feed solution, and composition of the feed solution on the extraction efficiency (E%) were verified. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100963t Exemplaires
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Titre : Comparison study on the adsorption of CFC - 115 and HFC - 125 on activated carbon and silicalite - 1 Type de document : texte imprimé Auteurs : Yong Peng, Auteur ; Fumin Zhang, Auteur ; Xiao Zheng, Auteur Année de publication : 2011 Article en page(s) : pp. 10009–10015 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Adsorption Activated carbon Silicalite Résumé : The adsorption isotherms of CFC-115 (1-chloro-1,1,2,2,2-pentafluoroethane) and HFC-125 (1,1,1,2,2-pentafluoroethane) on Vruf activated carbon (Calgon Carbon Corp.; brand code, VRU-F) and silicalite-1 have been accurately measured at pressures up to 120 kPa and temperatures ranging from 273 to 348 K. The Tóth or dual-site Langmuir (DSL) model appropriately describes the equilibrium data for the adsorptives CFC-115 and HFC-125 on Vruf carbon or silicalite-1, respectively. Because HFC-125 molecule has a higher packing efficiency in the pores of Vruf carbon, its saturation capacity extracted by the Tóth model is higher than that for CFC-115. For CFC-115, a “kink” in the isotherm on silicalite-1 is observed at about 4 molecules (unit cell of silicalite-1)−1, and the measured isotherms of CFC-115 for the first time show a second-step adsorption at loadings over 4 molecules (unit cell)−1. This is ascribed to a large difference in the adsorption entropy between the molecular locations in the intersections and in the channels. The DSL model with fixed saturation capacities describes this behavior well. The mixture adsorption isotherms predicted by the ideal adsorbed solution theory show that both adsorbents could be industrially applicable in the separation of CFC-115 and HFC-125. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1010806
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10009–10015[article] Comparison study on the adsorption of CFC - 115 and HFC - 125 on activated carbon and silicalite - 1 [texte imprimé] / Yong Peng, Auteur ; Fumin Zhang, Auteur ; Xiao Zheng, Auteur . - 2011 . - pp. 10009–10015.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10009–10015
Mots-clés : Adsorption Activated carbon Silicalite Résumé : The adsorption isotherms of CFC-115 (1-chloro-1,1,2,2,2-pentafluoroethane) and HFC-125 (1,1,1,2,2-pentafluoroethane) on Vruf activated carbon (Calgon Carbon Corp.; brand code, VRU-F) and silicalite-1 have been accurately measured at pressures up to 120 kPa and temperatures ranging from 273 to 348 K. The Tóth or dual-site Langmuir (DSL) model appropriately describes the equilibrium data for the adsorptives CFC-115 and HFC-125 on Vruf carbon or silicalite-1, respectively. Because HFC-125 molecule has a higher packing efficiency in the pores of Vruf carbon, its saturation capacity extracted by the Tóth model is higher than that for CFC-115. For CFC-115, a “kink” in the isotherm on silicalite-1 is observed at about 4 molecules (unit cell of silicalite-1)−1, and the measured isotherms of CFC-115 for the first time show a second-step adsorption at loadings over 4 molecules (unit cell)−1. This is ascribed to a large difference in the adsorption entropy between the molecular locations in the intersections and in the channels. The DSL model with fixed saturation capacities describes this behavior well. The mixture adsorption isotherms predicted by the ideal adsorbed solution theory show that both adsorbents could be industrially applicable in the separation of CFC-115 and HFC-125. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1010806 Exemplaires
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Titre : Gas and liquid axial mixing in the column packed with mellapak 250Y, pall rings 25, and intalox saddles 25 under flow conditions prevailing in distillation columns Type de document : texte imprimé Auteurs : L. Valenz, Auteur ; F. J. Rejl, Auteur ; V. Linek, Auteur Année de publication : 2011 Article en page(s) : pp. 10016-10025 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Distillation column Pall ring Axial mixing Résumé : The axial dispersions of gas and liquid phase in a column of inner diameter 0.297 m packed with random packing of metal Pall rings 25 and Intalox saddles 25 and structured packing of Mellapak 250Y were measured using a dynamic method under hydraulic conditions common in distillation columns, i.e., liquid flow rate from 6.94 x 10-4 to 0.0111 m/s and gas flow rate from 0.25 to 2 m/s. The two-response method with a diffusion-type model was used to reproduce the experimental response curves. Axial mixing in the gas increases with gas and liquid rates for both random and structured packings, but the dependence on the gas rate is very weak for the structured packing. The largest gas mixing was found for the Pall rings at the highest gas rate; the least was found for the structured packing at the lowest gas and liquid rates. Liquid-phase axial mixing increases with decreasing liquid flow rate and is independent of gas flow rate for both random and structured packings. The largest liquid mixing was found for the Intalox saddles at the lowest liquid rate; the least was found for the structured packing. The correlations of BoL and BoG numbers deduced for all types of packings used reproduced the experimental data within ±22%. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325824
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10016-10025[article] Gas and liquid axial mixing in the column packed with mellapak 250Y, pall rings 25, and intalox saddles 25 under flow conditions prevailing in distillation columns [texte imprimé] / L. Valenz, Auteur ; F. J. Rejl, Auteur ; V. Linek, Auteur . - 2011 . - pp. 10016-10025.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10016-10025
Mots-clés : Distillation column Pall ring Axial mixing Résumé : The axial dispersions of gas and liquid phase in a column of inner diameter 0.297 m packed with random packing of metal Pall rings 25 and Intalox saddles 25 and structured packing of Mellapak 250Y were measured using a dynamic method under hydraulic conditions common in distillation columns, i.e., liquid flow rate from 6.94 x 10-4 to 0.0111 m/s and gas flow rate from 0.25 to 2 m/s. The two-response method with a diffusion-type model was used to reproduce the experimental response curves. Axial mixing in the gas increases with gas and liquid rates for both random and structured packings, but the dependence on the gas rate is very weak for the structured packing. The largest gas mixing was found for the Pall rings at the highest gas rate; the least was found for the structured packing at the lowest gas and liquid rates. Liquid-phase axial mixing increases with decreasing liquid flow rate and is independent of gas flow rate for both random and structured packings. The largest liquid mixing was found for the Intalox saddles at the lowest liquid rate; the least was found for the structured packing. The correlations of BoL and BoG numbers deduced for all types of packings used reproduced the experimental data within ±22%. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325824 Exemplaires
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Titre : Effect of the membrane quality on gas permeation and chemical vapor deposition modification of MFI - type zeolite membranes Type de document : texte imprimé Auteurs : Xuefeng Zhu, Auteur ; Haibing Wang, Auteur ; Y. S. Lin, Auteur Année de publication : 2011 Article en page(s) : pp. 10026–10033 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Gas Chemical vapor Zeolite Résumé : Chemical vapor deposition (CVD) with methyldiethoxysilane (MDES) for MFI zeolitic pore size reduction is an effective way to improve the H2/CO2 separation factor of zeolite membranes. However, only good membranes with few intercrystalline defects are able to show considerable improvement in H2/CO2 separation factor through CVD modification. It is unreliable to evaluate the membrane quality on the basis of the H2/SF6 or N2/SF6 ideal separation factor because the SF6 adsorption-induced crystal swelling causes shrinkage of the intercrystalline defects in the MFI zeolite membranes. In this study, the quality of MFI zeolite membranes was evaluated on the basis of their performance in separating equimolar H2/CO2 mixture gas at room temperature. High-quality membranes are more selective to CO2 molecules rather than H2 at room temperature due to the adsorption of CO2 into the zeolitic pores and blocking of the pore channels for H2 diffusion. The effectiveness of the quality evaluation method was confirmed by on-stream CVD modification of MFI zeolite membranes with different initial H2/CO2 separation factors/ideal separation factors at room temperature. Experimental results showed that only those membranes with low H2/CO2 separation factor at room temperature (good membranes) showed improvement in H2/CO2 separation factor through CVD modification. For the CVD modified zeolite membrane with good initial quality, the permeance of H2 is lower than that of He with an activated diffusion behavior for small gas molecules in the modified zeolitic pores. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101101z
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10026–10033[article] Effect of the membrane quality on gas permeation and chemical vapor deposition modification of MFI - type zeolite membranes [texte imprimé] / Xuefeng Zhu, Auteur ; Haibing Wang, Auteur ; Y. S. Lin, Auteur . - 2011 . - pp. 10026–10033.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10026–10033
Mots-clés : Gas Chemical vapor Zeolite Résumé : Chemical vapor deposition (CVD) with methyldiethoxysilane (MDES) for MFI zeolitic pore size reduction is an effective way to improve the H2/CO2 separation factor of zeolite membranes. However, only good membranes with few intercrystalline defects are able to show considerable improvement in H2/CO2 separation factor through CVD modification. It is unreliable to evaluate the membrane quality on the basis of the H2/SF6 or N2/SF6 ideal separation factor because the SF6 adsorption-induced crystal swelling causes shrinkage of the intercrystalline defects in the MFI zeolite membranes. In this study, the quality of MFI zeolite membranes was evaluated on the basis of their performance in separating equimolar H2/CO2 mixture gas at room temperature. High-quality membranes are more selective to CO2 molecules rather than H2 at room temperature due to the adsorption of CO2 into the zeolitic pores and blocking of the pore channels for H2 diffusion. The effectiveness of the quality evaluation method was confirmed by on-stream CVD modification of MFI zeolite membranes with different initial H2/CO2 separation factors/ideal separation factors at room temperature. Experimental results showed that only those membranes with low H2/CO2 separation factor at room temperature (good membranes) showed improvement in H2/CO2 separation factor through CVD modification. For the CVD modified zeolite membrane with good initial quality, the permeance of H2 is lower than that of He with an activated diffusion behavior for small gas molecules in the modified zeolitic pores. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101101z Exemplaires
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Titre : CO2 Nucleation in Membrane Spacer Channels Remove Biofilms and Fouling Deposits Type de document : texte imprimé Auteurs : Ikenna S. Ngene, Auteur ; Rob G. H. Lammertink, Auteur ; Antoine J. B. Kemperman, Auteur Année de publication : 2011 Article en page(s) : pp. 10034–10039 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Biofilms Résumé : The decline in membrane performance due to both biofouling and particulate fouling is a major issue for membranes in the water treatment industry. In spiral wound modules, commonly used in reverse osmosis and nanofiltration, the presence of feed spacers results in an increased potential of fouling. We describe a novel cleaning method to be used in the restoration of membrane module performance. The method described here involves the use of water saturated with dissolved CO2 at higher pressures and rinsing of the fouled membrane/spacer channel at a lower pressure. Due to depressurization, bubbles nucleate at spacer filaments and improve the cleaning efficacy significantly. The study compared the cleaning efficacy of three methods in the removal of fouling from a membrane/spacer channel; water rinsing, water/N2 sparging, and water/CO2 (dissolved) nucleation. Using water rinsing, 40% of the fouling on the spacer-filled channel could be removed; a water/N2 mixture removed 85% of the fouling. With the dissolved water/CO2, there was complete removal of the fouling (all measured as restoration of the hydraulic resistance of the clean channels). Such an efficient tool to recover the performance of severely fouled desalination membrane modules could replace or reduce today’s expensive, sensitive, and chemically intensive cleaning processes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1011245
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10034–10039[article] CO2 Nucleation in Membrane Spacer Channels Remove Biofilms and Fouling Deposits [texte imprimé] / Ikenna S. Ngene, Auteur ; Rob G. H. Lammertink, Auteur ; Antoine J. B. Kemperman, Auteur . - 2011 . - pp. 10034–10039.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10034–10039
Mots-clés : Biofilms Résumé : The decline in membrane performance due to both biofouling and particulate fouling is a major issue for membranes in the water treatment industry. In spiral wound modules, commonly used in reverse osmosis and nanofiltration, the presence of feed spacers results in an increased potential of fouling. We describe a novel cleaning method to be used in the restoration of membrane module performance. The method described here involves the use of water saturated with dissolved CO2 at higher pressures and rinsing of the fouled membrane/spacer channel at a lower pressure. Due to depressurization, bubbles nucleate at spacer filaments and improve the cleaning efficacy significantly. The study compared the cleaning efficacy of three methods in the removal of fouling from a membrane/spacer channel; water rinsing, water/N2 sparging, and water/CO2 (dissolved) nucleation. Using water rinsing, 40% of the fouling on the spacer-filled channel could be removed; a water/N2 mixture removed 85% of the fouling. With the dissolved water/CO2, there was complete removal of the fouling (all measured as restoration of the hydraulic resistance of the clean channels). Such an efficient tool to recover the performance of severely fouled desalination membrane modules could replace or reduce today’s expensive, sensitive, and chemically intensive cleaning processes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1011245 Exemplaires
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Titre : Rapid measurement of gas solubility in liquids using a membrane dispersion microcontactor Type de document : texte imprimé Auteurs : Jing Tan, Auteur ; Jianhong Xu, Auteur ; Kai Wang, Auteur Année de publication : 2011 Article en page(s) : pp. 10040–10045 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Dispersion Solubility Résumé : In this study, we present a simple and fast method for the measurement of gas solubility in different liquids. Gas solubility measurements were carried out in a microcontactor using microdispersions to enhance mass transfer. The gas−liquid microcontactor, with a 5 μm pore size microfiltration membrane as the dispersion medium, was used to measure the gas solubility of six typical gas−liquid systems. The gas−liquid systems reached vapor−liquid equilibrium within 2 s, much less time than the 24 h required by the widely used static method of measurement. The obtained gas solubility data agree well with those obtained using the static method. The results produced using this measurement method were also highly reproducible, and relative measurement errors were less than 10% at the optimized operating conditions. The present method can potentially be very useful for the accurate and rapid measurement of gas solubility in many areas including gas−liquid reactions and solvent-based CO2 capture. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325827
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10040–10045[article] Rapid measurement of gas solubility in liquids using a membrane dispersion microcontactor [texte imprimé] / Jing Tan, Auteur ; Jianhong Xu, Auteur ; Kai Wang, Auteur . - 2011 . - pp. 10040–10045.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10040–10045
Mots-clés : Dispersion Solubility Résumé : In this study, we present a simple and fast method for the measurement of gas solubility in different liquids. Gas solubility measurements were carried out in a microcontactor using microdispersions to enhance mass transfer. The gas−liquid microcontactor, with a 5 μm pore size microfiltration membrane as the dispersion medium, was used to measure the gas solubility of six typical gas−liquid systems. The gas−liquid systems reached vapor−liquid equilibrium within 2 s, much less time than the 24 h required by the widely used static method of measurement. The obtained gas solubility data agree well with those obtained using the static method. The results produced using this measurement method were also highly reproducible, and relative measurement errors were less than 10% at the optimized operating conditions. The present method can potentially be very useful for the accurate and rapid measurement of gas solubility in many areas including gas−liquid reactions and solvent-based CO2 capture. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325827 Exemplaires
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Titre : Process intensification in HiGee absorption and distillation : Design procedure and applications Type de document : texte imprimé Auteurs : Lava Agarwal, Auteur ; V. Pavani, Auteur ; D. P. Rao, Auteur Année de publication : 2011 Article en page(s) : pp. 10046–10058 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Design Distillation Résumé : HiGee technology is emerging as an alternative to conventional tray and packed towers for mass-transfer applications. To evaluate the process intensification (volume reduction) potential of the technology, a systematic design procedure is developed in this work. HiGee designs using split packing innovation of Chandra et al. [Ind. Eng. Chem. Res. 2005, 44, 4051-4060] are developed for four industrially relevant distillation and absorption systems. Comparison with conventional packed or tray tower designs shows that significant volume reduction is possible. For the systems studied, the process intensification achieved is particularly impressive when the gas side mass-transfer resistance is dominant. The results suggest that split packing design innovation may be particularly suitable for intensification of gas side mass-transfer resistance controlled processes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325828
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10046–10058[article] Process intensification in HiGee absorption and distillation : Design procedure and applications [texte imprimé] / Lava Agarwal, Auteur ; V. Pavani, Auteur ; D. P. Rao, Auteur . - 2011 . - pp. 10046–10058.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10046–10058
Mots-clés : Design Distillation Résumé : HiGee technology is emerging as an alternative to conventional tray and packed towers for mass-transfer applications. To evaluate the process intensification (volume reduction) potential of the technology, a systematic design procedure is developed in this work. HiGee designs using split packing innovation of Chandra et al. [Ind. Eng. Chem. Res. 2005, 44, 4051-4060] are developed for four industrially relevant distillation and absorption systems. Comparison with conventional packed or tray tower designs shows that significant volume reduction is possible. For the systems studied, the process intensification achieved is particularly impressive when the gas side mass-transfer resistance is dominant. The results suggest that split packing design innovation may be particularly suitable for intensification of gas side mass-transfer resistance controlled processes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325828 Exemplaires
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Titre : Local optima in model - based optimal experimental design Type de document : texte imprimé Auteurs : Jan C. Schoneberger, Auteur ; Harvey Arellano-Garcia, Auteur ; Günter Wozny, Auteur Année de publication : 2011 Article en page(s) : pp. 10059–10073 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Optimal Résumé : Model-based nonlinear optimal experimental design (OED) has advanced to a relevant systematic tool in model development. However, the high nonlinearity of OED problems and their required high computational effort makes the optimization a challenging task. The objective of this work is to point out a crucial aspect of OED problems, namely, the existence of local minima. For this purpose, general characteristics of OED problems are presented and discussed, using different OED criteria and approaches (sequential/parallel). Furthermore, five different approaches are compared to overcome the local minima problem. Tuning options to improve the computation time of hybrid approaches are derived and discussed. The approaches are compared, based on the results of two case studies. To solve high-dimensional complex OED problems, a proposed hybrid framework is found to be a promising approach. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9016094
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10059–10073[article] Local optima in model - based optimal experimental design [texte imprimé] / Jan C. Schoneberger, Auteur ; Harvey Arellano-Garcia, Auteur ; Günter Wozny, Auteur . - 2011 . - pp. 10059–10073.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10059–10073
Mots-clés : Optimal Résumé : Model-based nonlinear optimal experimental design (OED) has advanced to a relevant systematic tool in model development. However, the high nonlinearity of OED problems and their required high computational effort makes the optimization a challenging task. The objective of this work is to point out a crucial aspect of OED problems, namely, the existence of local minima. For this purpose, general characteristics of OED problems are presented and discussed, using different OED criteria and approaches (sequential/parallel). Furthermore, five different approaches are compared to overcome the local minima problem. Tuning options to improve the computation time of hybrid approaches are derived and discussed. The approaches are compared, based on the results of two case studies. To solve high-dimensional complex OED problems, a proposed hybrid framework is found to be a promising approach. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9016094 Exemplaires
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Titre : Experimental investigations into the insecticidal, fungicidal, and bactericidal properties of pyrolysis bio - oil from tobacco leaves using a fluidized bed pilot plant Type de document : texte imprimé Auteurs : Christina J. Booker, Auteur ; Rohan Bedmutha, Auteur ; Tiffany Vogel, Auteur Année de publication : 2011 Article en page(s) : pp. 10074–10079 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Bio oil Bactericidal Résumé : Tobacco bio-oil, gases, and char were produced through pyrolysis of tobacco leaves using a fluidized bed pilot plant under varying temperature (350, 400, 450, 500, 550, and 600 °C) and residence time (5, 10, and 17 s) conditions. The optimized condition for the production of bio-oil was found to be at 500 °C at a vapor residence time of 5 s, giving a bio-oil yield of 43.4%. The Colorado Potato Beetle (CPB) Leptinotarsa decemlineata L. (Coleoptera: Chrysomelidae), a destructive pest toward potato crops, and three microorganisms (Streptomyces scabies, Clavibacter michiganensis, and Pythium ultimum), all problematic in Canadian agriculture, were strongly affected by tobacco bio-oil generated at all pyrolysis temperatures. Nicotine-free fractions of the tobacco bio-oil were prepared through liquid−liquid extraction, and high mortality rates for the CPB and inhibited growth for the microorganisms were still observed. A potential pesticide from tobacco bio-oil adds value to the biomass as well as the pyrolysis process. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100329z
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10074–10079[article] Experimental investigations into the insecticidal, fungicidal, and bactericidal properties of pyrolysis bio - oil from tobacco leaves using a fluidized bed pilot plant [texte imprimé] / Christina J. Booker, Auteur ; Rohan Bedmutha, Auteur ; Tiffany Vogel, Auteur . - 2011 . - pp. 10074–10079.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10074–10079
Mots-clés : Bio oil Bactericidal Résumé : Tobacco bio-oil, gases, and char were produced through pyrolysis of tobacco leaves using a fluidized bed pilot plant under varying temperature (350, 400, 450, 500, 550, and 600 °C) and residence time (5, 10, and 17 s) conditions. The optimized condition for the production of bio-oil was found to be at 500 °C at a vapor residence time of 5 s, giving a bio-oil yield of 43.4%. The Colorado Potato Beetle (CPB) Leptinotarsa decemlineata L. (Coleoptera: Chrysomelidae), a destructive pest toward potato crops, and three microorganisms (Streptomyces scabies, Clavibacter michiganensis, and Pythium ultimum), all problematic in Canadian agriculture, were strongly affected by tobacco bio-oil generated at all pyrolysis temperatures. Nicotine-free fractions of the tobacco bio-oil were prepared through liquid−liquid extraction, and high mortality rates for the CPB and inhibited growth for the microorganisms were still observed. A potential pesticide from tobacco bio-oil adds value to the biomass as well as the pyrolysis process. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100329z Exemplaires
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Titre : Modeling the closure of thief zones in carbonate reservoirs using acids Type de document : texte imprimé Auteurs : Hamidreza Salimi, Auteur ; Karl-Heinz Wolf, Auteur ; Johannes Bruining, Auteur Année de publication : 2011 Article en page(s) : pp. 10080–10093 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Carbonate Acids Résumé : Carbonate oil reservoirs can contain fractures and dissolution-vug pore space that may cause short-circuit flows between injection and production well. As a result, injected water bypasses the larger part of the reservoir, leaving much oil unproduced. This paper investigates the concept of reducing the permeability in the fracture that is causing the short-circuit flow by injecting a mixture of sulfuric acid and hydrochloric acid. During the process, reservoir rock dissolves and gypsum subsequently precipitates. We formulate a mathematical and numerical model that simulates the coinjection of sulfuric acid (H2SO4) with hydrochloric acid (HCl) into carbonate rock for both one- and two-dimensional settings. The carbonate rock contains a single fracture. A one-dimensional simulation of the process shows that upstream dissolution is the dominant process, whereas precipitation of gypsum occurs downstream. The two-dimensional simulation shows that downstream fractures are clogged, whereas continuous paths are created upstream. We find that the injection flow rate and acid ratio are the two main factors that influence precipitation and dissolution patterns within a fracture. The results show qualitative agreement with experimental results obtained in the Dietz−De Josseling laboratory. We conclude that injection of an acid mixture can be used to improve water-drive recovery performance from oil reservoirs that contain fractures between injection and production well. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100616x
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10080–10093[article] Modeling the closure of thief zones in carbonate reservoirs using acids [texte imprimé] / Hamidreza Salimi, Auteur ; Karl-Heinz Wolf, Auteur ; Johannes Bruining, Auteur . - 2011 . - pp. 10080–10093.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10080–10093
Mots-clés : Carbonate Acids Résumé : Carbonate oil reservoirs can contain fractures and dissolution-vug pore space that may cause short-circuit flows between injection and production well. As a result, injected water bypasses the larger part of the reservoir, leaving much oil unproduced. This paper investigates the concept of reducing the permeability in the fracture that is causing the short-circuit flow by injecting a mixture of sulfuric acid and hydrochloric acid. During the process, reservoir rock dissolves and gypsum subsequently precipitates. We formulate a mathematical and numerical model that simulates the coinjection of sulfuric acid (H2SO4) with hydrochloric acid (HCl) into carbonate rock for both one- and two-dimensional settings. The carbonate rock contains a single fracture. A one-dimensional simulation of the process shows that upstream dissolution is the dominant process, whereas precipitation of gypsum occurs downstream. The two-dimensional simulation shows that downstream fractures are clogged, whereas continuous paths are created upstream. We find that the injection flow rate and acid ratio are the two main factors that influence precipitation and dissolution patterns within a fracture. The results show qualitative agreement with experimental results obtained in the Dietz−De Josseling laboratory. We conclude that injection of an acid mixture can be used to improve water-drive recovery performance from oil reservoirs that contain fractures between injection and production well. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100616x Exemplaires
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Titre : Hydrogel nanopowder production by inverse - miniemulsion polymerization and supercritical drying Type de document : texte imprimé Auteurs : Melinda G. Hemingway, Auteur ; Gupta, Ram B., Auteur ; David J. Elton, Auteur Année de publication : 2011 Article en page(s) : pp. 10094–10099 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Drying Supercritical state Polymerization Production Résumé : Hydrogel nanoparticles can be successfully produced by polymerization in inverse miniemulsions, for use in a variety of applications including diagnosis, drug delivery, separation, soil stabilization, and absorption. Unfortunately, conventional drying techniques result in agglomerated powder due to the sticky nature of the wet hydrogel particles. This work utilizes supercritical CO2 drying to obtain free-flowing hydrogel nanoparticles. Polyacrylamide hydrogel nanoparticles (100 nm in diameter) are produced in an inverse miniemulsion composed of a cyclohexane continuous phase, a water dispersed phase, and a nonionic surfactant. The polymerized miniemulsion is dried by injection into supercritical CO2 which results in rapid removal of cyclohexane, water, and surfactant. The morphology, particle size, and size distribution of the nanoparticles are determined using dynamic light scattering and scanning electron microscopy. The proposed miniemulsion polymerization supercritical drying (MPSD) method produces a hydrogel nanopowder with much lower agglomeration or residual surfactant as compared to convention drying. In addition, the MPSD method produced solvent-free nanoparticles due to efficient extraction by supercritical CO2. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325832
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10094–10099[article] Hydrogel nanopowder production by inverse - miniemulsion polymerization and supercritical drying [texte imprimé] / Melinda G. Hemingway, Auteur ; Gupta, Ram B., Auteur ; David J. Elton, Auteur . - 2011 . - pp. 10094–10099.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10094–10099
Mots-clés : Drying Supercritical state Polymerization Production Résumé : Hydrogel nanoparticles can be successfully produced by polymerization in inverse miniemulsions, for use in a variety of applications including diagnosis, drug delivery, separation, soil stabilization, and absorption. Unfortunately, conventional drying techniques result in agglomerated powder due to the sticky nature of the wet hydrogel particles. This work utilizes supercritical CO2 drying to obtain free-flowing hydrogel nanoparticles. Polyacrylamide hydrogel nanoparticles (100 nm in diameter) are produced in an inverse miniemulsion composed of a cyclohexane continuous phase, a water dispersed phase, and a nonionic surfactant. The polymerized miniemulsion is dried by injection into supercritical CO2 which results in rapid removal of cyclohexane, water, and surfactant. The morphology, particle size, and size distribution of the nanoparticles are determined using dynamic light scattering and scanning electron microscopy. The proposed miniemulsion polymerization supercritical drying (MPSD) method produces a hydrogel nanopowder with much lower agglomeration or residual surfactant as compared to convention drying. In addition, the MPSD method produced solvent-free nanoparticles due to efficient extraction by supercritical CO2. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325832 Exemplaires
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Titre : Aspects to be considered for the development of a correlation algorithm for condensed phase equilibrium data of ternary systems Type de document : texte imprimé Auteurs : A. Marcilla, Auteur ; M. M. Olaya, Auteur ; M. D. Serrano, Auteur Année de publication : 2011 Article en page(s) : pp. 10100–10110 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Phase equilibrium Ternary systems Résumé : The existing commercial software packages for equilibrium data correlation, or analogous tools included in chemical process simulators, have been widely used and their extensive capabilities are well-known. Nevertheless, and as far as LLE calculations are concerned, they have been designed for the simplest equilibrium behavior. For example, for ternary systems, only the correlation of type 1 and type 2 LLE data is possible. None of these applications allows for the correlation of type 0 LLE, type 3 LLLE, or type 4 LLSE systems, although these are interesting for many industrial purposes. To enable a possible extension of such software, a robust computation algorithm has been developed to correlate phase equilibrium data among condensed phases for all of these more complicated behaviors. Moreover, this algorithm includes some new strategies to avoid the main problems occurring through correlation procedures, which lead to convergence problems or inconsistent results. These strategies are explained in detail in the present work. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1010383
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10100–10110[article] Aspects to be considered for the development of a correlation algorithm for condensed phase equilibrium data of ternary systems [texte imprimé] / A. Marcilla, Auteur ; M. M. Olaya, Auteur ; M. D. Serrano, Auteur . - 2011 . - pp. 10100–10110.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10100–10110
Mots-clés : Phase equilibrium Ternary systems Résumé : The existing commercial software packages for equilibrium data correlation, or analogous tools included in chemical process simulators, have been widely used and their extensive capabilities are well-known. Nevertheless, and as far as LLE calculations are concerned, they have been designed for the simplest equilibrium behavior. For example, for ternary systems, only the correlation of type 1 and type 2 LLE data is possible. None of these applications allows for the correlation of type 0 LLE, type 3 LLLE, or type 4 LLSE systems, although these are interesting for many industrial purposes. To enable a possible extension of such software, a robust computation algorithm has been developed to correlate phase equilibrium data among condensed phases for all of these more complicated behaviors. Moreover, this algorithm includes some new strategies to avoid the main problems occurring through correlation procedures, which lead to convergence problems or inconsistent results. These strategies are explained in detail in the present work. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1010383 Exemplaires
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Titre : Dynamical modeling and experimental analysis on the swelling behavior of the sIPN hydrogels Type de document : texte imprimé Auteurs : Saman Sotoudeh, Auteur ; Ghazaleh Pourfallah, Auteur ; Abolfazl Barati, Auteur Année de publication : 2011 Article en page(s) : pp. 10111–10115 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Dynamic Hydrogels Résumé : In this article, polyethylene glycol-acrylamide (PEG-AAm) hydrogels were experimentally prepared with a matrix structure and their swelling behaviors were tested. Different amounts of polyethylene glycol, acrylic acid, and acrylamide were added, and an optimum case was discovered. Effect of some parameters on the swelling was then investigated. A dynamic model based on the Maxwell−Stefan equation, Nernst−Planck equation, and Donnan theory was developed to consider the swelling behavior of hydrogels. These equations were applied to model the buffer diffusion inside the hydrogels in the swelling process. COMSOL software was also applied to simulate the swelling behavior in the hydrogels. The results showed that the data obtained from the modeling were in good agreement with the experimental data (the deviation value was around 16%). Further, COMSOL was able to simulate water diffusion process in the hydrogels, properly. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101062d
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10111–10115[article] Dynamical modeling and experimental analysis on the swelling behavior of the sIPN hydrogels [texte imprimé] / Saman Sotoudeh, Auteur ; Ghazaleh Pourfallah, Auteur ; Abolfazl Barati, Auteur . - 2011 . - pp. 10111–10115.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10111–10115
Mots-clés : Dynamic Hydrogels Résumé : In this article, polyethylene glycol-acrylamide (PEG-AAm) hydrogels were experimentally prepared with a matrix structure and their swelling behaviors were tested. Different amounts of polyethylene glycol, acrylic acid, and acrylamide were added, and an optimum case was discovered. Effect of some parameters on the swelling was then investigated. A dynamic model based on the Maxwell−Stefan equation, Nernst−Planck equation, and Donnan theory was developed to consider the swelling behavior of hydrogels. These equations were applied to model the buffer diffusion inside the hydrogels in the swelling process. COMSOL software was also applied to simulate the swelling behavior in the hydrogels. The results showed that the data obtained from the modeling were in good agreement with the experimental data (the deviation value was around 16%). Further, COMSOL was able to simulate water diffusion process in the hydrogels, properly. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101062d Exemplaires
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Titre : Simulation of flow behavior of particles in a liquid − solid fluidized bed Type de document : texte imprimé Auteurs : Shuyan Wang, Auteur ; Xiaoqi Li, Auteur ; Yanbo Wu, Auteur Année de publication : 2011 Article en page(s) : pp. 10116-10124 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Fluidized bed Fluidization Résumé : Understanding hydrodynamics of liquid—solid fluidized beds is crucial in proper scale-up and design of these reactors. Computational fluid dynamics (CFD) models have shown promise in gaining this understanding. In this paper, a two-dimensional CFD model, using an Eulerian—Eulerian two-fluid model incorporating the kinetic theory of granular flow, is used to describe the liquid—solid two-phase flow in a liquid—solid fluidized bed. The predicted pressure gradient data and concentrations are found to agree with experimental data published in the literature. Furthermore, the model is used to investigate the influences of the superficial liquid velocity and the sold particle size on the distribution of solids concentration. The simulation results showed that the solids concentration has a relatively uniform distribution and high bed expansion with the increase of liquid velocity and decrease of particles sizes. Solids mean axial velocities decrease with the decrease in superficial liquid velocity. The static bed height plays a minor role on the effect of velocity and concentration distribution in numerical simulations of liquid—solid bubbling fluidized beds. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325835
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10116-10124[article] Simulation of flow behavior of particles in a liquid − solid fluidized bed [texte imprimé] / Shuyan Wang, Auteur ; Xiaoqi Li, Auteur ; Yanbo Wu, Auteur . - 2011 . - pp. 10116-10124.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10116-10124
Mots-clés : Fluidized bed Fluidization Résumé : Understanding hydrodynamics of liquid—solid fluidized beds is crucial in proper scale-up and design of these reactors. Computational fluid dynamics (CFD) models have shown promise in gaining this understanding. In this paper, a two-dimensional CFD model, using an Eulerian—Eulerian two-fluid model incorporating the kinetic theory of granular flow, is used to describe the liquid—solid two-phase flow in a liquid—solid fluidized bed. The predicted pressure gradient data and concentrations are found to agree with experimental data published in the literature. Furthermore, the model is used to investigate the influences of the superficial liquid velocity and the sold particle size on the distribution of solids concentration. The simulation results showed that the solids concentration has a relatively uniform distribution and high bed expansion with the increase of liquid velocity and decrease of particles sizes. Solids mean axial velocities decrease with the decrease in superficial liquid velocity. The static bed height plays a minor role on the effect of velocity and concentration distribution in numerical simulations of liquid—solid bubbling fluidized beds. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325835 Exemplaires
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Titre : High - temperature pyrolysis of blended animal manures for producing renewable energy and value - added biochar Type de document : texte imprimé Auteurs : Kyoung S. Ro, Auteur ; Keri B. Cantrell, Auteur ; Patrick G. Hunt, Auteur Année de publication : 2011 Article en page(s) : pp. 10125–10131 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Pyrolysis Renewable energy Résumé : In this study, we used a commercial pilot-scale pyrolysis reactor system to produce combustible gas and biochar at 620 °C from three sources (chicken litter, swine solids, mixture of swine solids with rye grass). Pyrolysis of swine solids produced gas with the greatest higher heating value (HHV) followed by the mixture of swine solids with rye grass and chicken litter. Relatively high S-containing gases were produced; dimethyl sulfide and methyl mercaptan concentrations were higher than the OSHA PEL limits. Biochar yield ranged from 43 to 49% based on dry weight with about 53% of carbon recovery. Whereas the HHV of the chicken litter biochar was slightly below that of low rank coals, swine-based biochars had HHVs between high and low rank coals. Approximately 50% of the feedstock energy was retained in biochar and 25% in produced gases. Manure biochars contained higher concentrations of P and K than that of original manure feedstocks. Consequently, these could be used as a low-grade fertilizer to improve soil fertility and crop yields. Extremely high energy (232.3 MJ/kg) was required to make 1 kg of biochar from wet swine manure with 97% MC. However, dewatering of the wet swine manure to 75% MC substantially reduced the external energy requirement by 19 folds. Mixing of dried biomass such as rye grass with the dewatered swine solids almost eliminated the need for external energy. If one can copyrolyze wet animal wastes with additional feedstock that are drier and more energy dense than rye grass such as waste plastic pellets, it may be possible to produce both valuable biochar and extra power. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101155m
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10125–10131[article] High - temperature pyrolysis of blended animal manures for producing renewable energy and value - added biochar [texte imprimé] / Kyoung S. Ro, Auteur ; Keri B. Cantrell, Auteur ; Patrick G. Hunt, Auteur . - 2011 . - pp. 10125–10131.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10125–10131
Mots-clés : Pyrolysis Renewable energy Résumé : In this study, we used a commercial pilot-scale pyrolysis reactor system to produce combustible gas and biochar at 620 °C from three sources (chicken litter, swine solids, mixture of swine solids with rye grass). Pyrolysis of swine solids produced gas with the greatest higher heating value (HHV) followed by the mixture of swine solids with rye grass and chicken litter. Relatively high S-containing gases were produced; dimethyl sulfide and methyl mercaptan concentrations were higher than the OSHA PEL limits. Biochar yield ranged from 43 to 49% based on dry weight with about 53% of carbon recovery. Whereas the HHV of the chicken litter biochar was slightly below that of low rank coals, swine-based biochars had HHVs between high and low rank coals. Approximately 50% of the feedstock energy was retained in biochar and 25% in produced gases. Manure biochars contained higher concentrations of P and K than that of original manure feedstocks. Consequently, these could be used as a low-grade fertilizer to improve soil fertility and crop yields. Extremely high energy (232.3 MJ/kg) was required to make 1 kg of biochar from wet swine manure with 97% MC. However, dewatering of the wet swine manure to 75% MC substantially reduced the external energy requirement by 19 folds. Mixing of dried biomass such as rye grass with the dewatered swine solids almost eliminated the need for external energy. If one can copyrolyze wet animal wastes with additional feedstock that are drier and more energy dense than rye grass such as waste plastic pellets, it may be possible to produce both valuable biochar and extra power. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101155m Exemplaires
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Titre : Pretreatment and fractionation of wheat straw by an acetone - based organosolv process Type de document : texte imprimé Auteurs : Wouter J. J. Huijgen, Auteur ; Johannes H. Reith, Auteur ; Herman den Uil, Auteur Année de publication : 2011 Article en page(s) : pp. 10132–10140 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Acetone Organosolv Résumé : Acetone-based organosolv fractionation of wheat straw was studied to produce sugars and lignin in a lignocellulose biorefinery. The influence of acetone−water ratio, reaction time, and temperature on fractionation degree, lignin yield, and enzymatic digestibility of the cellulose fraction was examined. The solvent−water ratio was found to influence delignification and hemicellulose hydrolysis by its effect on lignin solubility and pH. Organosolv treatment in 50:50% w/w acetone−water during 1 h at 205 °C resulted in 82% hemicellulose hydrolysis, 79% delignification, and 93% cellulose recovery. A substantial part of the sugars formed upon hemicellulose hydrolysis seems to have reacted further including possible formation of lignin−furfural condensation products. Finally, aqueous acetone pretreatment was found to substantially improve the enzymatic digestibility of the cellulose fraction (glucose yield: up to 87% vs 16% for untreated wheat straw). DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101247w
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10132–10140[article] Pretreatment and fractionation of wheat straw by an acetone - based organosolv process [texte imprimé] / Wouter J. J. Huijgen, Auteur ; Johannes H. Reith, Auteur ; Herman den Uil, Auteur . - 2011 . - pp. 10132–10140.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10132–10140
Mots-clés : Acetone Organosolv Résumé : Acetone-based organosolv fractionation of wheat straw was studied to produce sugars and lignin in a lignocellulose biorefinery. The influence of acetone−water ratio, reaction time, and temperature on fractionation degree, lignin yield, and enzymatic digestibility of the cellulose fraction was examined. The solvent−water ratio was found to influence delignification and hemicellulose hydrolysis by its effect on lignin solubility and pH. Organosolv treatment in 50:50% w/w acetone−water during 1 h at 205 °C resulted in 82% hemicellulose hydrolysis, 79% delignification, and 93% cellulose recovery. A substantial part of the sugars formed upon hemicellulose hydrolysis seems to have reacted further including possible formation of lignin−furfural condensation products. Finally, aqueous acetone pretreatment was found to substantially improve the enzymatic digestibility of the cellulose fraction (glucose yield: up to 87% vs 16% for untreated wheat straw). DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101247w Exemplaires
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Titre : Use of an artificial neural network algorithm to determine pressure − temperature phase diagrams of tert - butylamine + methane and tert - butylamine + hydrogen binary hydrates Type de document : texte imprimé Auteurs : Amir H. Mohammadi, Auteur ; Dominique Richon, Auteur Année de publication : 2011 Article en page(s) : pp. 10141–10143 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Phase diagram Algorithm Neural networ Résumé : In this communication, we have developed a feed forward artificial neural network algorithm for estimating dissociation pressures of binary hydrates of tert-butylamine + methane and tert-butylamine + hydrogen, as a function of temperature and concentration of tert-butylamine in aqueous solution. To develop this algorithm, experimental data reported in the literature on the dissociation pressures of the aforementioned binary hydrates have been used. It is shown that this ANN algorithm can be regarded as a useful tool to model these hydrate systems. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325838
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10141–10143[article] Use of an artificial neural network algorithm to determine pressure − temperature phase diagrams of tert - butylamine + methane and tert - butylamine + hydrogen binary hydrates [texte imprimé] / Amir H. Mohammadi, Auteur ; Dominique Richon, Auteur . - 2011 . - pp. 10141–10143.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10141–10143
Mots-clés : Phase diagram Algorithm Neural networ Résumé : In this communication, we have developed a feed forward artificial neural network algorithm for estimating dissociation pressures of binary hydrates of tert-butylamine + methane and tert-butylamine + hydrogen, as a function of temperature and concentration of tert-butylamine in aqueous solution. To develop this algorithm, experimental data reported in the literature on the dissociation pressures of the aforementioned binary hydrates have been used. It is shown that this ANN algorithm can be regarded as a useful tool to model these hydrate systems. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325838 Exemplaires
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Titre : Regeneration of sulfur deactivated Ni - based biomass syngas cleaning catalysts Type de document : texte imprimé Auteurs : Liyu Li, Auteur ; Christopher Howard, Auteur ; David L. King, Auteur Année de publication : 2011 Article en page(s) : pp. 10144–10148 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Biomass Catalysts Résumé : Nickel-based catalysts have been widely tested for reforming undesired tar and methane from hot biomass-derived syngas. However, nickel catalysts readily deactivate through the adsorption of sulfur compounds in the syngas. We report a new regeneration process that can effectively regenerate sulfur-poisoned Ni reforming catalysts. This process consists of four sequential treatments: (1) controlled oxidation at 750 °C in 1% O2, (2) decomposition at 900 °C in inert gas, (3) reduction at 900 °C in 2% H2, and (4) reaction at 900 °C under reforming condition. This 4-step regeneration process might have advantages over the conventional steam regeneration process. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101032x
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10144–10148[article] Regeneration of sulfur deactivated Ni - based biomass syngas cleaning catalysts [texte imprimé] / Liyu Li, Auteur ; Christopher Howard, Auteur ; David L. King, Auteur . - 2011 . - pp. 10144–10148.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10144–10148
Mots-clés : Biomass Catalysts Résumé : Nickel-based catalysts have been widely tested for reforming undesired tar and methane from hot biomass-derived syngas. However, nickel catalysts readily deactivate through the adsorption of sulfur compounds in the syngas. We report a new regeneration process that can effectively regenerate sulfur-poisoned Ni reforming catalysts. This process consists of four sequential treatments: (1) controlled oxidation at 750 °C in 1% O2, (2) decomposition at 900 °C in inert gas, (3) reduction at 900 °C in 2% H2, and (4) reaction at 900 °C under reforming condition. This 4-step regeneration process might have advantages over the conventional steam regeneration process. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101032x Exemplaires
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Titre : Prediction of henry’s law constant of organic compounds in water from a new group - contribution - based model Type de document : texte imprimé Auteurs : Farhad Gharagheizi, Auteur ; Reza Abbasi, Auteur ; Behnam Tirandazi, Auteur Année de publication : 2011 Article en page(s) : pp. 10149-10152 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Modeling Prediction Résumé : In this work, a new model is presented for estimation of Henry's law constant of pure compounds in water at 25 °C (H). This model is based on a combination between a group contribution method and neural networks. The needed parameters of the model are the occurrences of a new collection of 107 functional groups. On the basis of these 107 functional groups, a feed forward neural network is presented to estimate the H of pure compounds. The squared correlation coefficient, absolute percent error, standard deviation error, and root-mean-square error of the model over a diverse set of 1940 pure compounds used are, respectively, 0.9981, 2.84%, 2.4, and 0.1 (all the values obtained using log H based data). Therefore, the model is a comprehensive and an accurate model and can be used to predict the H of a wide range of chemical families of pure compounds in water better than previously presented models. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325840
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10149-10152[article] Prediction of henry’s law constant of organic compounds in water from a new group - contribution - based model [texte imprimé] / Farhad Gharagheizi, Auteur ; Reza Abbasi, Auteur ; Behnam Tirandazi, Auteur . - 2011 . - pp. 10149-10152.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 10149-10152
Mots-clés : Modeling Prediction Résumé : In this work, a new model is presented for estimation of Henry's law constant of pure compounds in water at 25 °C (H). This model is based on a combination between a group contribution method and neural networks. The needed parameters of the model are the occurrences of a new collection of 107 functional groups. On the basis of these 107 functional groups, a feed forward neural network is presented to estimate the H of pure compounds. The squared correlation coefficient, absolute percent error, standard deviation error, and root-mean-square error of the model over a diverse set of 1940 pure compounds used are, respectively, 0.9981, 2.84%, 2.4, and 0.1 (all the values obtained using log H based data). Therefore, the model is a comprehensive and an accurate model and can be used to predict the H of a wide range of chemical families of pure compounds in water better than previously presented models. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325840 Exemplaires
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