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Vol. 48 N°3 - Février 2009 [texte imprimé] . - 2009 . - p. 1067-1682 : ill. ; 28 cm. Chemical engineering Langues : Anglais (eng)
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Ajouter le résultat dans votre panierSimulation of biodiesel production through transesterification of vegetable oils / Scott Stiefel in Industrial & engineering chemistry research, Vol. 48 N°3 (Février 2009)
Titre : Simulation of biodiesel production through transesterification of vegetable oils Type de document : texte imprimé Auteurs : Scott Stiefel, Auteur ; Gustavo Dassori, Auteur Année de publication : 2009 Article en page(s) : p. 1068–1071 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Bioenergy Biodiesel Vegetable oils Résumé : Biodiesel can be produced from a number of natural, renewable sources, but vegetable oils are the main feedstocks. Most existing biodiesel plants currently rely upon the use of a homogeneous catalyst in a continuous reactor system, using the transesterification of soybean or rapeseed oil with methanol into alkyl esters. A key differentiation characteristic among the existing processes is that of the mixing pattern employed in the system. The present study compares reactor performances in terms of biodiesel yields for plug flow and complete mixing behaviors, along with the use of interstage phase separation. It is concluded that plug flow pattern shows a distinctive benefit in terms of yields and reactor volume reduction compared to complete mixing. Interstage separation improves the reacting system yields when proper phase separation can be achieved, maximizing glycerine removal from the downstream system. Staged mechanically stirred tank reactors can reach similar performances as plug flow behavior systems without resorting to interstage separation under the conditions here studied. Methanol/oil ratio can improve the reacting system performance and reduce differences, even if plug flow reactors are not employed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8005512
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1068–1071[article] Simulation of biodiesel production through transesterification of vegetable oils [texte imprimé] / Scott Stiefel, Auteur ; Gustavo Dassori, Auteur . - 2009 . - p. 1068–1071.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1068–1071
Mots-clés : Bioenergy Biodiesel Vegetable oils Résumé : Biodiesel can be produced from a number of natural, renewable sources, but vegetable oils are the main feedstocks. Most existing biodiesel plants currently rely upon the use of a homogeneous catalyst in a continuous reactor system, using the transesterification of soybean or rapeseed oil with methanol into alkyl esters. A key differentiation characteristic among the existing processes is that of the mixing pattern employed in the system. The present study compares reactor performances in terms of biodiesel yields for plug flow and complete mixing behaviors, along with the use of interstage phase separation. It is concluded that plug flow pattern shows a distinctive benefit in terms of yields and reactor volume reduction compared to complete mixing. Interstage separation improves the reacting system yields when proper phase separation can be achieved, maximizing glycerine removal from the downstream system. Staged mechanically stirred tank reactors can reach similar performances as plug flow behavior systems without resorting to interstage separation under the conditions here studied. Methanol/oil ratio can improve the reacting system performance and reduce differences, even if plug flow reactors are not employed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8005512 Exemplaires
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Titre : Flow regime diagnosis in bubble columns via pressure fluctuations and computer-assisted radioactive particle tracking measurements Type de document : texte imprimé Auteurs : María Sol Fraguío, Auteur ; Miryan C. Cassanello, Auteur ; Sujatha Degaleesan, Auteur ; Milorad Dudukovic, Auteur Année de publication : 2009 Article en page(s) : p. 1072–1080 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Flow regime Bubble columns industrial column Radioactivite Résumé : The importance of diagnosing the flow regime in bubble columns by noninvasive and easy-to-implement methods is well-known. Hence, the aim of this work is to diagnose the flow regime in a pilot scale bubble column by comparing the attractor that gives the fingerprint of a tested underlying hydrodynamic condition against the attractor of a reference condition, using the statistical S test, developed by Diks et al.(1) The attractors are reconstructed from the time series of two characteristic variables: the trajectory of a liquid flow follower, determined by CARPT (computer-assisted particle tracking), and pressure fluctuations. Since CARPT fully maps the hydrodynamics in multiphase systems in a Lagrangian sense, the tracer particle trajectory time series is used to establish the optimal set of parameters required for the S test when analyzing pressure fluctuations. This work demonstrates that the same set of optimal parameters determined when applying the S test to CARPT experimental time series leads to successful flow regime identification when applying the global S test to pressure fluctuation signals detected at various locations. This validates the use of pressure fluctuation signals in industrial settings as an economic way to detect flow regimes. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800549d
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1072–1080[article] Flow regime diagnosis in bubble columns via pressure fluctuations and computer-assisted radioactive particle tracking measurements [texte imprimé] / María Sol Fraguío, Auteur ; Miryan C. Cassanello, Auteur ; Sujatha Degaleesan, Auteur ; Milorad Dudukovic, Auteur . - 2009 . - p. 1072–1080.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1072–1080
Mots-clés : Flow regime Bubble columns industrial column Radioactivite Résumé : The importance of diagnosing the flow regime in bubble columns by noninvasive and easy-to-implement methods is well-known. Hence, the aim of this work is to diagnose the flow regime in a pilot scale bubble column by comparing the attractor that gives the fingerprint of a tested underlying hydrodynamic condition against the attractor of a reference condition, using the statistical S test, developed by Diks et al.(1) The attractors are reconstructed from the time series of two characteristic variables: the trajectory of a liquid flow follower, determined by CARPT (computer-assisted particle tracking), and pressure fluctuations. Since CARPT fully maps the hydrodynamics in multiphase systems in a Lagrangian sense, the tracer particle trajectory time series is used to establish the optimal set of parameters required for the S test when analyzing pressure fluctuations. This work demonstrates that the same set of optimal parameters determined when applying the S test to CARPT experimental time series leads to successful flow regime identification when applying the global S test to pressure fluctuation signals detected at various locations. This validates the use of pressure fluctuation signals in industrial settings as an economic way to detect flow regimes. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800549d Exemplaires
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Titre : Low trans and saturated vegetable oil hydrogenation over nanostructured Pd/silica catalysts : process parameters and mass-transfer features effects Type de document : texte imprimé Auteurs : Khaled Belkacemi, Auteur ; Safia Hamoudi, Auteur Année de publication : 2009 Article en page(s) : p. 1081–1089 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Catalytic hydogenation Pd catalyst Hydogenation Vegetable oils Résumé : Sunflower and canola oils were hydrogenated over a novel Pd catalyst and a commercial N catalyst. The Pd catalyst consisted of palladium nanoparticles highly dispersed on mesostructured silica material. The effect of temperature (80−130 °C) and H2 pressure (3.6−9.3 atm) on the activity, selectivity, and trans (TFA) and saturated (SFA) fatty acids formation were studied for both oils and types of catalysts. It was found that the reaction temperature and the hydrogen pressure increased the activity of both catalysts and controlled the solubility of hydrogen and the cis/trans isomerization. The Pd catalyst exhibited a greater selectivity toward the formation of monoene in comparison to the commercial Ni catalyst. Partial hydrogenation of both oils from initial iodine (IVo) value of 120−130 to a final IV of 90 with the nanostructured Pd catalyst using a conventional stirred reactor equipped with a surface aeration turbine-type impeller yielded modified oils with low TFA level (7−10%) and also controlled the formation SFA (∼7%) under mild process conditions. Further reduction of TFA level was achieved when the hydrogenation of vegetable oils over Pd catalyst was carried out with a reactor equipped with a gas-inducing sparger-type impeller having enhanced mass-transfer features. Very low TFA ( En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800559v
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1081–1089[article] Low trans and saturated vegetable oil hydrogenation over nanostructured Pd/silica catalysts : process parameters and mass-transfer features effects [texte imprimé] / Khaled Belkacemi, Auteur ; Safia Hamoudi, Auteur . - 2009 . - p. 1081–1089.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1081–1089
Mots-clés : Catalytic hydogenation Pd catalyst Hydogenation Vegetable oils Résumé : Sunflower and canola oils were hydrogenated over a novel Pd catalyst and a commercial N catalyst. The Pd catalyst consisted of palladium nanoparticles highly dispersed on mesostructured silica material. The effect of temperature (80−130 °C) and H2 pressure (3.6−9.3 atm) on the activity, selectivity, and trans (TFA) and saturated (SFA) fatty acids formation were studied for both oils and types of catalysts. It was found that the reaction temperature and the hydrogen pressure increased the activity of both catalysts and controlled the solubility of hydrogen and the cis/trans isomerization. The Pd catalyst exhibited a greater selectivity toward the formation of monoene in comparison to the commercial Ni catalyst. Partial hydrogenation of both oils from initial iodine (IVo) value of 120−130 to a final IV of 90 with the nanostructured Pd catalyst using a conventional stirred reactor equipped with a surface aeration turbine-type impeller yielded modified oils with low TFA level (7−10%) and also controlled the formation SFA (∼7%) under mild process conditions. Further reduction of TFA level was achieved when the hydrogenation of vegetable oils over Pd catalyst was carried out with a reactor equipped with a gas-inducing sparger-type impeller having enhanced mass-transfer features. Very low TFA ( En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800559v Exemplaires
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Titre : Simulation of a membrane reactor for the catalytic oxidehydrogenation of ethane Type de document : texte imprimé Auteurs : María L. Rodriguez, Auteur ; Daniel E. Ardissone, Auteur ; Angeliki A. Lemonidou, Auteur ; Eleni Heracleous, Auteur Année de publication : 2009 Article en page(s) : p. 1090–1095 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ethylene Catalytic Oxidehydrogenation Reactor catalytic Résumé : Industrial-scale ethylene production using a novel membrane multitubular reactor for the ethane oxidative dehydrogenation process over a Ni−Nb−O catalyst is proposed. A theoretical study was performed by means of a pseudohomogeneous model of the tube and shell sides. The feasibility and convenience of using this novel design, as well as the influence of the main operating variables on the reactor performance, were analyzed. The introduction of the membrane leads to lower oxygen partial pressures inside the catalyst tubes when compared with a conventional multitubular reactor. This leads to very good ethylene selectivities, good temperature control as a result of lower heat generation rates, and reasonable production rates. The reactor performance appears to be highly affected by the balance between the rate of oxygen consumption by the chemical reaction and its rate of permeation through the membrane. Under certain operating conditions leading to lower reaction rates, an undesired accumulation of oxygen inside the tubes is observed. A minimum amount of O2 injected at the tube mouth appears beneficial to overcoming this accumulation phenomenon. The membrane reactor shows a nonconventional inverse parametric sensitivity with respect to the inlet temperature. When the reactor is operated at conditions where the reaction is controlled by the permeation flow of O2 through the membrane, it is possible to reach high selectivities to ethylene, significant ethane conversions, and mild temperature profiles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800564v
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1090–1095[article] Simulation of a membrane reactor for the catalytic oxidehydrogenation of ethane [texte imprimé] / María L. Rodriguez, Auteur ; Daniel E. Ardissone, Auteur ; Angeliki A. Lemonidou, Auteur ; Eleni Heracleous, Auteur . - 2009 . - p. 1090–1095.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1090–1095
Mots-clés : Ethylene Catalytic Oxidehydrogenation Reactor catalytic Résumé : Industrial-scale ethylene production using a novel membrane multitubular reactor for the ethane oxidative dehydrogenation process over a Ni−Nb−O catalyst is proposed. A theoretical study was performed by means of a pseudohomogeneous model of the tube and shell sides. The feasibility and convenience of using this novel design, as well as the influence of the main operating variables on the reactor performance, were analyzed. The introduction of the membrane leads to lower oxygen partial pressures inside the catalyst tubes when compared with a conventional multitubular reactor. This leads to very good ethylene selectivities, good temperature control as a result of lower heat generation rates, and reasonable production rates. The reactor performance appears to be highly affected by the balance between the rate of oxygen consumption by the chemical reaction and its rate of permeation through the membrane. Under certain operating conditions leading to lower reaction rates, an undesired accumulation of oxygen inside the tubes is observed. A minimum amount of O2 injected at the tube mouth appears beneficial to overcoming this accumulation phenomenon. The membrane reactor shows a nonconventional inverse parametric sensitivity with respect to the inlet temperature. When the reactor is operated at conditions where the reaction is controlled by the permeation flow of O2 through the membrane, it is possible to reach high selectivities to ethylene, significant ethane conversions, and mild temperature profiles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800564v Exemplaires
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Titre : Vapor-liquid equilibrium study in trickle-bed reactors Type de document : texte imprimé Auteurs : Jinwen Chen, Auteur ; Neil Wang, Auteur ; Fabian Mederos, Auteur ; Jorge Ancheyta, Auteur Année de publication : 2009 Article en page(s) : p. 1096–1106 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Vapor-liquid Hydrodynamique des fluides Reactors Résumé : Vapor−liquid equilibrium (VLE) in trickle-bed hydroprocessing reactors can significantly change the fluid hydrodynamics and the distribution of reacting species in both the vapor and liquid phases and, ultimately, change the reactor performance. VLE is especially important to pilot-plant studies in which ideal operating regimes (plug flow, full catalyst wetting, absence of reactor wall effects, etc.) are desired to generate reliable, reproducible, and representative data for commercial scale-up and kinetics studies. In this article, we report VLE flash experiments that were conducted in a continuous-flow unit with hydrogen and various petroleum middle distillates under typical hydrotreating conditions to study the relative distribution of the oil in the two phases. The experimental data were further used to evaluate the interaction coefficients, required to perform VLE flash calculations, between hydrogen and hydrocarbon boiling-point pseudocomponents. Furthermore, flow hydrodynamics were predicted in a pilot-plant trickle-bed reactor for hydrotreating two different middle distillate feeds to provide a mapping of operating conditions under which the desired operating regimes could be maintained. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8006006
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1096–1106[article] Vapor-liquid equilibrium study in trickle-bed reactors [texte imprimé] / Jinwen Chen, Auteur ; Neil Wang, Auteur ; Fabian Mederos, Auteur ; Jorge Ancheyta, Auteur . - 2009 . - p. 1096–1106.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1096–1106
Mots-clés : Vapor-liquid Hydrodynamique des fluides Reactors Résumé : Vapor−liquid equilibrium (VLE) in trickle-bed hydroprocessing reactors can significantly change the fluid hydrodynamics and the distribution of reacting species in both the vapor and liquid phases and, ultimately, change the reactor performance. VLE is especially important to pilot-plant studies in which ideal operating regimes (plug flow, full catalyst wetting, absence of reactor wall effects, etc.) are desired to generate reliable, reproducible, and representative data for commercial scale-up and kinetics studies. In this article, we report VLE flash experiments that were conducted in a continuous-flow unit with hydrogen and various petroleum middle distillates under typical hydrotreating conditions to study the relative distribution of the oil in the two phases. The experimental data were further used to evaluate the interaction coefficients, required to perform VLE flash calculations, between hydrogen and hydrocarbon boiling-point pseudocomponents. Furthermore, flow hydrodynamics were predicted in a pilot-plant trickle-bed reactor for hydrotreating two different middle distillate feeds to provide a mapping of operating conditions under which the desired operating regimes could be maintained. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8006006 Exemplaires
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Titre : Fundamental kinetic modeling of catalytic reforming Type de document : texte imprimé Auteurs : Rogelio Sotelo-Boyás, Auteur ; Gilbert F. Froment, Auteur Année de publication : 2009 Article en page(s) : p. 1107–1119 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Catalytic kinetic Résumé : A fundamental kinetic model for the catalytic reforming process has been developed. The complex network of elementary steps and molecular reactions occurring in catalytic reforming was generated through a computer algorithm characterizing the various species by means of vectors and Boolean relation matrices. The algorithm is based on the fundamental chemistry occurring on both acid and metal sites of a Pt−Sn/Al2O3 catalyst. The number of rate coefficients for the transformations occurring on the metal sites was reduced by relating them to the nature of the involved carbon atoms. The single event concept was applied in the development of rate expressions for the elementary steps on the acid sites. This approach allows obtaining rate coefficients that are independent of the feedstock, owing to their fundamental chemical nature. The Levenberg−Marquardt algorithm was used to estimate the rate coefficients. The estimation was based on data reported from a previous naphtha reforming study in a fixed bed reactor with Pt−Sn/Al2O3 as a catalyst. The agreement between the experimental and estimated yields is excellent. The statistical tests were also satisfied. The kinetic model was used in pseudo-homogeneous and heterogeneous reactor models simulating an industrial three-bed adiabatic catalytic reformer with centripetal radial flow. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800607e
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1107–1119[article] Fundamental kinetic modeling of catalytic reforming [texte imprimé] / Rogelio Sotelo-Boyás, Auteur ; Gilbert F. Froment, Auteur . - 2009 . - p. 1107–1119.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1107–1119
Mots-clés : Catalytic kinetic Résumé : A fundamental kinetic model for the catalytic reforming process has been developed. The complex network of elementary steps and molecular reactions occurring in catalytic reforming was generated through a computer algorithm characterizing the various species by means of vectors and Boolean relation matrices. The algorithm is based on the fundamental chemistry occurring on both acid and metal sites of a Pt−Sn/Al2O3 catalyst. The number of rate coefficients for the transformations occurring on the metal sites was reduced by relating them to the nature of the involved carbon atoms. The single event concept was applied in the development of rate expressions for the elementary steps on the acid sites. This approach allows obtaining rate coefficients that are independent of the feedstock, owing to their fundamental chemical nature. The Levenberg−Marquardt algorithm was used to estimate the rate coefficients. The estimation was based on data reported from a previous naphtha reforming study in a fixed bed reactor with Pt−Sn/Al2O3 as a catalyst. The agreement between the experimental and estimated yields is excellent. The statistical tests were also satisfied. The kinetic model was used in pseudo-homogeneous and heterogeneous reactor models simulating an industrial three-bed adiabatic catalytic reformer with centripetal radial flow. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800607e Exemplaires
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Titre : Performance analysis of a smelting reactor for copper production process Type de document : texte imprimé Auteurs : Pimporn Chamveha, Auteur ; Kattiyapon Chaichana, Auteur ; Anon Chuachuensuk, Auteur ; Suthida Authayanun, Auteur Année de publication : 2009 Article en page(s) : p. 1120–1125 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Copper Chemical Reactor Résumé : A primary smelting reactor (PSR) is an important unit in the pyrometallurgical process for the production of copper. This article presents a performance analysis of a PSR with respect to the effects of various operating parameters. The model of the PSR was developed using a metallurgical process simulator, METSIM. Reactor parameters, i.e., heat loss and phase distributions of matte and slag, were estimated from actual plant data. The model predictions were validated with plant data, and good agreement was observed. The developed PSR model was used to analyze the influence of the feed rates of copper concentrate, oxygen, silica flux, and revert on the PSR performance in terms of the percentage of copper in white metal and PSR slag, the percentage of magnetite and silica in PSR slag, and reactor temperature En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800618a
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1120–1125[article] Performance analysis of a smelting reactor for copper production process [texte imprimé] / Pimporn Chamveha, Auteur ; Kattiyapon Chaichana, Auteur ; Anon Chuachuensuk, Auteur ; Suthida Authayanun, Auteur . - 2009 . - p. 1120–1125.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1120–1125
Mots-clés : Copper Chemical Reactor Résumé : A primary smelting reactor (PSR) is an important unit in the pyrometallurgical process for the production of copper. This article presents a performance analysis of a PSR with respect to the effects of various operating parameters. The model of the PSR was developed using a metallurgical process simulator, METSIM. Reactor parameters, i.e., heat loss and phase distributions of matte and slag, were estimated from actual plant data. The model predictions were validated with plant data, and good agreement was observed. The developed PSR model was used to analyze the influence of the feed rates of copper concentrate, oxygen, silica flux, and revert on the PSR performance in terms of the percentage of copper in white metal and PSR slag, the percentage of magnetite and silica in PSR slag, and reactor temperature En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800618a Exemplaires
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Titre : Modification of activity and selectivity of NiMo/SBA-15 HDS catalysts by grafting of different metal oxides on the support surface Type de document : texte imprimé Auteurs : Tatiana Klimova, Auteur ; Laura Peña, Auteur ; Lilia Lizama, Auteur ; Cecilia Salcedo, Auteur Année de publication : 2009 Article en page(s) : p. 1126–1133 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Catalysts Metal Oxides Résumé : In the context of searching for new catalysts for hydrodesulfurization (HDS) of petroleum, in the present work a series of NiMo catalysts supported on SBA-15 materials modified by different metal oxides were prepared and tested in dibenzothiophene HDS. The behavior of the HDS catalysts prepared using SBA-15 supports grafted with alkaline earth metal oxides (MgO, CaO, BaO) is described for the first time and compared to that observed for the supports modified with alumina (Al2O3) or transition metal oxides (TiO2, ZrO2) in order to inquire into the effect of the nature of the metal oxide incorporated in the support on the catalytic activity and selectivity of the NiMo catalysts. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800626k
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1126–1133[article] Modification of activity and selectivity of NiMo/SBA-15 HDS catalysts by grafting of different metal oxides on the support surface [texte imprimé] / Tatiana Klimova, Auteur ; Laura Peña, Auteur ; Lilia Lizama, Auteur ; Cecilia Salcedo, Auteur . - 2009 . - p. 1126–1133.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1126–1133
Mots-clés : Catalysts Metal Oxides Résumé : In the context of searching for new catalysts for hydrodesulfurization (HDS) of petroleum, in the present work a series of NiMo catalysts supported on SBA-15 materials modified by different metal oxides were prepared and tested in dibenzothiophene HDS. The behavior of the HDS catalysts prepared using SBA-15 supports grafted with alkaline earth metal oxides (MgO, CaO, BaO) is described for the first time and compared to that observed for the supports modified with alumina (Al2O3) or transition metal oxides (TiO2, ZrO2) in order to inquire into the effect of the nature of the metal oxide incorporated in the support on the catalytic activity and selectivity of the NiMo catalysts. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800626k Exemplaires
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Titre : Three-dimensional model of a membrane reactor configuration with cooling tubes Type de document : texte imprimé Auteurs : A. Ramírez Serrano, Auteur ; F. Tiscareño Lechuga, Auteur ; J. A. Ochoa Tapia, Auteur Année de publication : 2009 Article en page(s) : p. 1134–1139 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Membrane reactors Cooling tubes Résumé : Membrane reactors are a promising alternative to carry out reactions in which the selectivity can be enhanced by the controlled addition of reactants. In addition, it also is very important to keep the temperature profile within a favorable range. In this work a new configuration is proposed for a membrane reactor with internal heat transfer sources. The configuration is similar to that of a shell and tube heat exchanger with the differences that the shell side is packed with catalyst and some of the tubes are membranes. Although the model assumes plug flow, it considers changes in the superficial velocities due to temperature profiles and variations of the molar flow rates. This geometry requires three-dimensional considerations; however, the solution took advantage of a pseudo-three-dimensional model. Controlled addition of reactant through the membrane not only reduces the effect of the side reactions but also alleviates the hot spots since the rates of reactions are decreased. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800641h
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1134–1139[article] Three-dimensional model of a membrane reactor configuration with cooling tubes [texte imprimé] / A. Ramírez Serrano, Auteur ; F. Tiscareño Lechuga, Auteur ; J. A. Ochoa Tapia, Auteur . - 2009 . - p. 1134–1139.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1134–1139
Mots-clés : Membrane reactors Cooling tubes Résumé : Membrane reactors are a promising alternative to carry out reactions in which the selectivity can be enhanced by the controlled addition of reactants. In addition, it also is very important to keep the temperature profile within a favorable range. In this work a new configuration is proposed for a membrane reactor with internal heat transfer sources. The configuration is similar to that of a shell and tube heat exchanger with the differences that the shell side is packed with catalyst and some of the tubes are membranes. Although the model assumes plug flow, it considers changes in the superficial velocities due to temperature profiles and variations of the molar flow rates. This geometry requires three-dimensional considerations; however, the solution took advantage of a pseudo-three-dimensional model. Controlled addition of reactant through the membrane not only reduces the effect of the side reactions but also alleviates the hot spots since the rates of reactions are decreased. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800641h Exemplaires
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Titre : Monitoring filtration in trickle beds using electrical capacitance tomography Type de document : texte imprimé Auteurs : Mohsen Hamidipour, Auteur ; Faïçal Larachi, Auteur ; Zbigniew Ring, Auteur Année de publication : 2009 Article en page(s) : p. 1140–1153 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Trickle Beds -- Filtration Oil Hydrocarbon Résumé : Experiments were carried out to monitor the evolution of the deposition of fine particles in trickle-bed reactors during the flow of nonpolar hydrocarbon oil-like liquid suspensions using electrical capacitance tomography (ECT) imaging. The accuracy of the ECT rendition was validated in the pristine (i.e., deposit-free) bed state by comparing the liquid holdup measurements from ECT with the liquid holdup from residence time distribution (RTD) measurements. The pulse-flow characteristics (pulse velocity and frequency) estimated from the ECT signals were in agreement with existing literature data. For filtration experiments, the effects of the initial liquid suspension distribution, the gas and liquid superficial velocities, and single-phase flow (i.e., zero gas velocity) on the structure of the deposition in the bed were studied. ECT imaging successfully tracked the unsteady-state progression of bed plugging throughout the trickle bed. It was found that increasing the liquid or gas superficial velocity resulted in increased local deposition. The transition, due to deposition, from trickle to pulse flow was also determined from ECT. In the case of stagnant gas, a filter cake formed on top of the bed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800810t
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1140–1153[article] Monitoring filtration in trickle beds using electrical capacitance tomography [texte imprimé] / Mohsen Hamidipour, Auteur ; Faïçal Larachi, Auteur ; Zbigniew Ring, Auteur . - 2009 . - p. 1140–1153.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1140–1153
Mots-clés : Trickle Beds -- Filtration Oil Hydrocarbon Résumé : Experiments were carried out to monitor the evolution of the deposition of fine particles in trickle-bed reactors during the flow of nonpolar hydrocarbon oil-like liquid suspensions using electrical capacitance tomography (ECT) imaging. The accuracy of the ECT rendition was validated in the pristine (i.e., deposit-free) bed state by comparing the liquid holdup measurements from ECT with the liquid holdup from residence time distribution (RTD) measurements. The pulse-flow characteristics (pulse velocity and frequency) estimated from the ECT signals were in agreement with existing literature data. For filtration experiments, the effects of the initial liquid suspension distribution, the gas and liquid superficial velocities, and single-phase flow (i.e., zero gas velocity) on the structure of the deposition in the bed were studied. ECT imaging successfully tracked the unsteady-state progression of bed plugging throughout the trickle bed. It was found that increasing the liquid or gas superficial velocity resulted in increased local deposition. The transition, due to deposition, from trickle to pulse flow was also determined from ECT. In the case of stagnant gas, a filter cake formed on top of the bed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800810t Exemplaires
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Titre : Characterization and hydrogenation activity of Ni/Si(Al)- MCM-41 catalysts prepared by deposition-precipitation Type de document : texte imprimé Auteurs : Rubén Nares, Auteur ; Jorge Ramírez, Auteur ; Aída Gutiérrez-Alejandre, Auteur ; Rogelio Cuevas, Auteur Année de publication : 2009 Article en page(s) : p. 1154–1162 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Nickel phyllosilicate Catalysts spectroscopy Résumé : The deposition−precipitation (DP) method was used for the preparation of Ni/SiMCM-41 and Ni/AlMCM-41 catalysts with different DP times (1−4 h), and the catalysts were characterized by BET, XRD, TPR, FTIR spectroscopy, and TEM. On both types of catalysts, the Ni(II) phases formed are a mixture of 1:1 nickel phyllosilicate and Ni(OH)2. The quantity of each phase at the end of the deposition process determines the final Ni particle size; i.e., greater amounts of Ni(OH)2 lead to larger Ni particles. In addition, it was found that the presence of aluminum in the framework of MCM-41 delays the formation of the nickel hydrosilicate phase. As a result of the consumption of the siliceous pore walls during DP, the long-range order of the MCM-41 hexagonal pore structure is gradually lost. Catalytic activity in the hydrogenation of naphthalene was higher for Ni/SiMCM-41 catalysts and was a linear function of the exposed area of Ni particles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800569j
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1154–1162[article] Characterization and hydrogenation activity of Ni/Si(Al)- MCM-41 catalysts prepared by deposition-precipitation [texte imprimé] / Rubén Nares, Auteur ; Jorge Ramírez, Auteur ; Aída Gutiérrez-Alejandre, Auteur ; Rogelio Cuevas, Auteur . - 2009 . - p. 1154–1162.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1154–1162
Mots-clés : Nickel phyllosilicate Catalysts spectroscopy Résumé : The deposition−precipitation (DP) method was used for the preparation of Ni/SiMCM-41 and Ni/AlMCM-41 catalysts with different DP times (1−4 h), and the catalysts were characterized by BET, XRD, TPR, FTIR spectroscopy, and TEM. On both types of catalysts, the Ni(II) phases formed are a mixture of 1:1 nickel phyllosilicate and Ni(OH)2. The quantity of each phase at the end of the deposition process determines the final Ni particle size; i.e., greater amounts of Ni(OH)2 lead to larger Ni particles. In addition, it was found that the presence of aluminum in the framework of MCM-41 delays the formation of the nickel hydrosilicate phase. As a result of the consumption of the siliceous pore walls during DP, the long-range order of the MCM-41 hexagonal pore structure is gradually lost. Catalytic activity in the hydrogenation of naphthalene was higher for Ni/SiMCM-41 catalysts and was a linear function of the exposed area of Ni particles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800569j Exemplaires
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Titre : Study of the performance of catalysts for catalytic cracking by applying a lump-based kinetic model Type de document : texte imprimé Auteurs : R. Quintana-Solórzano, Auteur ; A. Rodríguez-Hernández, Auteur ; R. García-de-León, Auteur Année de publication : 2009 Article en page(s) : p. 1163–1171 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Catalysts Fluid catalytic cracking LPG Résumé : In catalytic cracking, catalysts selection is not a trivial task since a catalyst should exhibit a good hydrothermal stability as well as product distributions and qualities according to the necessities of the refinery. Cracking experiments at the bench scale in a fluidized confined-bed reactor at 789 K in the catalyst to oil range of 3.0−7.5 g/g using two industrial feeds have coupled to a five-lump kinetic model for a quantitative study of a set of cracking catalysts. To a gain insight into the catalysts performance, the assessment of raw rate coefficients has been complemented with a reaction pathways analysis. Primary cracking reactions are 1 order of magnitude higher than secondary ones, the gasoil to gasoline conversion being the fastest reaction. Up to 23% of the formed gasoline may undergo secondary cracking, more than 90% of it ending up in LPG. At the investigated conditions, coke formation is practically fully formed out of gasoline via secondary reactions and not from the gasoil. Cracking results are in concordance with catalyst properties, i.e., specific surface areas, and catalyst composition, e.g., the rate of secondary cracking of gasoline to LPG decreases with the zeolite and rare earths content. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800570z
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1163–1171[article] Study of the performance of catalysts for catalytic cracking by applying a lump-based kinetic model [texte imprimé] / R. Quintana-Solórzano, Auteur ; A. Rodríguez-Hernández, Auteur ; R. García-de-León, Auteur . - 2009 . - p. 1163–1171.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1163–1171
Mots-clés : Catalysts Fluid catalytic cracking LPG Résumé : In catalytic cracking, catalysts selection is not a trivial task since a catalyst should exhibit a good hydrothermal stability as well as product distributions and qualities according to the necessities of the refinery. Cracking experiments at the bench scale in a fluidized confined-bed reactor at 789 K in the catalyst to oil range of 3.0−7.5 g/g using two industrial feeds have coupled to a five-lump kinetic model for a quantitative study of a set of cracking catalysts. To a gain insight into the catalysts performance, the assessment of raw rate coefficients has been complemented with a reaction pathways analysis. Primary cracking reactions are 1 order of magnitude higher than secondary ones, the gasoil to gasoline conversion being the fastest reaction. Up to 23% of the formed gasoline may undergo secondary cracking, more than 90% of it ending up in LPG. At the investigated conditions, coke formation is practically fully formed out of gasoline via secondary reactions and not from the gasoil. Cracking results are in concordance with catalyst properties, i.e., specific surface areas, and catalyst composition, e.g., the rate of secondary cracking of gasoline to LPG decreases with the zeolite and rare earths content. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800570z Exemplaires
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Titre : Estimation of effectiveness factor for arbitrary particle shape and non-linear kinetics Type de document : texte imprimé Auteurs : Néstor J. Mariani, Auteur ; Clarisa Mocciaro, Auteur ; Osvaldo M. Martínez, Auteur ; Guillermo F. Barreto, Auteur Année de publication : 2009 Article en page(s) : p. 1172–1177 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Catalytic pellets -- analysis Generalized cylinder Résumé :
A one-dimensional model, called generalized cylinder (GC), is employed to analyze the diffusion−reaction problem in catalytic pellets of different shapes and nonlinear kinetics. The fitting parameter (σ) of the GC model was adjusted by matching the behavior of the actual pellet at high reaction rates. The errors of the GC model, considering five different kinetic expressions (isothermal zero and second order, isothermal Langmuir−Hinshelwood−Hougen−Watson type, first order exothermic, and first order endothermic) and four different catalytic pellet shapes turned out to be less than 3.5%.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800578p
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1172–1177[article] Estimation of effectiveness factor for arbitrary particle shape and non-linear kinetics [texte imprimé] / Néstor J. Mariani, Auteur ; Clarisa Mocciaro, Auteur ; Osvaldo M. Martínez, Auteur ; Guillermo F. Barreto, Auteur . - 2009 . - p. 1172–1177.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1172–1177
Mots-clés : Catalytic pellets -- analysis Generalized cylinder Résumé :
A one-dimensional model, called generalized cylinder (GC), is employed to analyze the diffusion−reaction problem in catalytic pellets of different shapes and nonlinear kinetics. The fitting parameter (σ) of the GC model was adjusted by matching the behavior of the actual pellet at high reaction rates. The errors of the GC model, considering five different kinetic expressions (isothermal zero and second order, isothermal Langmuir−Hinshelwood−Hougen−Watson type, first order exothermic, and first order endothermic) and four different catalytic pellet shapes turned out to be less than 3.5%.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800578p Exemplaires
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Titre : Kinetic study of the HDS of 4,6-DMDBT over NiMo/Al2O3-SiO2(x) catalysts Type de document : texte imprimé Auteurs : Felipe Sánchez-Minero, Auteur ; Jorge Ramírez, Auteur ; Rogelio Cuevas-Garcia, Auteur ; Aída Gutiérrez-Alejandre, Auteur Année de publication : 2009 Article en page(s) : p. 1178–1185 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Kinetic study NiMo catalyst Résumé :
Two NiMo/Al2O3-SiO2(x) catalysts with different SiO2 content in the support (0 and 10 wt %) were evaluated at four temperatures (560, 573, 585, and 598 K) in the HDS of 4,6-DMDBT. The reaction products (DMDP, MCHT, and DMDCH) were analyzed to establish a reaction scheme. Then, a kinetic study using Langmuir−Hinshelwood (LH) type equations was carried out to estimate the changes in the rate constants for the direct desulfurization and hydrogenation reaction routes involved in the HDS of 4,6-DMDBT. The results show that incorporation of SiO2 to the catalyst support increases the HDS of 4,6-DMDBT and that this increase is mainly due to a greater contribution of the hydrogenation reaction. The apparent activation energy and pre-exponential factor estimated for both reaction routes indicated an increase in the number of active sites related to the hydrogenation route when SiO2 is present in the catalyst. This result was corroborated by means of NO adsorption.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8005808
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1178–1185[article] Kinetic study of the HDS of 4,6-DMDBT over NiMo/Al2O3-SiO2(x) catalysts [texte imprimé] / Felipe Sánchez-Minero, Auteur ; Jorge Ramírez, Auteur ; Rogelio Cuevas-Garcia, Auteur ; Aída Gutiérrez-Alejandre, Auteur . - 2009 . - p. 1178–1185.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1178–1185
Mots-clés : Kinetic study NiMo catalyst Résumé :
Two NiMo/Al2O3-SiO2(x) catalysts with different SiO2 content in the support (0 and 10 wt %) were evaluated at four temperatures (560, 573, 585, and 598 K) in the HDS of 4,6-DMDBT. The reaction products (DMDP, MCHT, and DMDCH) were analyzed to establish a reaction scheme. Then, a kinetic study using Langmuir−Hinshelwood (LH) type equations was carried out to estimate the changes in the rate constants for the direct desulfurization and hydrogenation reaction routes involved in the HDS of 4,6-DMDBT. The results show that incorporation of SiO2 to the catalyst support increases the HDS of 4,6-DMDBT and that this increase is mainly due to a greater contribution of the hydrogenation reaction. The apparent activation energy and pre-exponential factor estimated for both reaction routes indicated an increase in the number of active sites related to the hydrogenation route when SiO2 is present in the catalyst. This result was corroborated by means of NO adsorption.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8005808 Exemplaires
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Titre : Transesterification of castor oil : effect of catalyst and co-solvent Type de document : texte imprimé Auteurs : Rosaura Peña, Auteur ; Rubi Romero, Auteur ; Sandra Luz Martínez, Auteur ; Maria Jesús Ramos, Auteur Année de publication : 2009 Article en page(s) : p. 1186–1189 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Biodiesel Castor Oil -- Transesterification Catalyst Methanol Résumé : Biodiesel is emerging as an alternative fuel with several advantages over the common petroleum based fuels. In its production, however, variables such as raw material, catalyst, and co-solvent are an issue worth exploring because of the impact they have on final biodiesel properties. Therefore, this work aims to establish the effect of the aforesaid variables on methyl ester content, viscosity, acidity, and water content of biodiesel produced from castor oil. In this context, the methanolysis of castor oil has been conducted at 60 °C in a batch reactor, and the effect of three alkaline catalysts (CH3ONa, NaOH, and KOH) and a co-solvent (hexane) has been established. It is concluded that sodium methoxide leads to considerably higher methyl ester content than the other essayed catalysts. Besides, when utilizing a co-solvent the methyl ester content increases up to a very close value (95.5%) to that established by the EN14214 norm (>96.5%). This has been ascribed to a significant improvement on oil−methanol contact. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8005929
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1186–1189[article] Transesterification of castor oil : effect of catalyst and co-solvent [texte imprimé] / Rosaura Peña, Auteur ; Rubi Romero, Auteur ; Sandra Luz Martínez, Auteur ; Maria Jesús Ramos, Auteur . - 2009 . - p. 1186–1189.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1186–1189
Mots-clés : Biodiesel Castor Oil -- Transesterification Catalyst Methanol Résumé : Biodiesel is emerging as an alternative fuel with several advantages over the common petroleum based fuels. In its production, however, variables such as raw material, catalyst, and co-solvent are an issue worth exploring because of the impact they have on final biodiesel properties. Therefore, this work aims to establish the effect of the aforesaid variables on methyl ester content, viscosity, acidity, and water content of biodiesel produced from castor oil. In this context, the methanolysis of castor oil has been conducted at 60 °C in a batch reactor, and the effect of three alkaline catalysts (CH3ONa, NaOH, and KOH) and a co-solvent (hexane) has been established. It is concluded that sodium methoxide leads to considerably higher methyl ester content than the other essayed catalysts. Besides, when utilizing a co-solvent the methyl ester content increases up to a very close value (95.5%) to that established by the EN14214 norm (>96.5%). This has been ascribed to a significant improvement on oil−methanol contact. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8005929 Exemplaires
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Titre : Carbon-modified alumina and alumina-carbon-supported hydrotreating catalysts Type de document : texte imprimé Auteurs : S. K. Maity, Auteur ; L. Flores, Auteur ; Jorge Ancheyta, Auteur ; H. Fukuyama, Auteur Année de publication : 2009 Article en page(s) : p. 1190–1195 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Energy Carbon Alumina Oil -- Hydrotreating Catalysts Résumé : Two types of supports, carbon-modified alumina and alumina−carbon, were prepared in this investigation. These supports were used to prepare hydrotreating (HDT) catalysts for Maya heavy crude. It was found that, when carbon was added to the alumina matrix and the carbon was then burned, pores having larger diameter were generated. The average pore diameter of the support increased with increasing amount of carbon in the alumina. However, when the carbon was not burned, the pore size decreased with added carbon. The hydrotreating activity results show that, because of the larger pore diameter and higher pore volume, the modified-alumina-supported PCoMo catalysts have slightly higher activities than the alumina−carbon-supported catalysts. The effects of additives, boron and phosphorus, on the hydrotreating of heavy oil were also compared. It was found that P-containing catalysts have higher activities than B-containing catalysts. It was also found that, when boron-containing catalyst were prepared at higher pH, they had higher hydrodemetalation (HDM) activities. Deactivation studies showed that the presence of carbon in the support might hinder rate of deactivation during hydrotreating of heavy oil. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800606p
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1190–1195[article] Carbon-modified alumina and alumina-carbon-supported hydrotreating catalysts [texte imprimé] / S. K. Maity, Auteur ; L. Flores, Auteur ; Jorge Ancheyta, Auteur ; H. Fukuyama, Auteur . - 2009 . - p. 1190–1195.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1190–1195
Mots-clés : Energy Carbon Alumina Oil -- Hydrotreating Catalysts Résumé : Two types of supports, carbon-modified alumina and alumina−carbon, were prepared in this investigation. These supports were used to prepare hydrotreating (HDT) catalysts for Maya heavy crude. It was found that, when carbon was added to the alumina matrix and the carbon was then burned, pores having larger diameter were generated. The average pore diameter of the support increased with increasing amount of carbon in the alumina. However, when the carbon was not burned, the pore size decreased with added carbon. The hydrotreating activity results show that, because of the larger pore diameter and higher pore volume, the modified-alumina-supported PCoMo catalysts have slightly higher activities than the alumina−carbon-supported catalysts. The effects of additives, boron and phosphorus, on the hydrotreating of heavy oil were also compared. It was found that P-containing catalysts have higher activities than B-containing catalysts. It was also found that, when boron-containing catalyst were prepared at higher pH, they had higher hydrodemetalation (HDM) activities. Deactivation studies showed that the presence of carbon in the support might hinder rate of deactivation during hydrotreating of heavy oil. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800606p Exemplaires
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Titre : Screening of ceria-based and commercial ceramic catalysts for catalytic ozonation of simulated olive mill wastewaters Type de document : texte imprimé Auteurs : Rui C. Martins, Auteur ; Rosa M. Quinta-Ferreira, Auteur Année de publication : 2009 Article en page(s) : p. 1196–1202 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Water Wastewater Commercial catalysts Catalytic Ozonation Résumé :
The efficiency of several commercial and laboratory catalysts in the catalytic ozonation of a simulated phenolic wastewater was tested. Experiments involving three ceria-based catalysts prepared in our laboratory, namely, Co−Ce−O (70/30), Ag−Ce−O (70/30), and Mn−Ce−O (70/30), were compared with those involving commercially available catalysts, namely, G66A (CuO−ZnO/Al2O3), N-150 (Fe2O3−MnOx), SG2216 (CuO−MnOx/Al2O3), and N-140 (CuO−MnOx). Of these, Mn−Ce−O (70/30) was found to be an interesting alternative because 80% of the total organic carbon was removed after 120 min of oxidation. The biodegradability of the simulated wastewater was assessed by measuring the ratio BOD5/COD before and after each treatment. Single and catalytic ozonation over Ag−Ce−O led to a less biodegradable effluent, whereas the rest of the catalytic systems truly enhanced the biodegradability of the simulated wastewater. Trends in the concentrations of some intermediates and the pH profiles were also analyzed for single and catalytic ozonation over Mn−Ce−O (70/30).En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8006209
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1196–1202[article] Screening of ceria-based and commercial ceramic catalysts for catalytic ozonation of simulated olive mill wastewaters [texte imprimé] / Rui C. Martins, Auteur ; Rosa M. Quinta-Ferreira, Auteur . - 2009 . - p. 1196–1202.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1196–1202
Mots-clés : Water Wastewater Commercial catalysts Catalytic Ozonation Résumé :
The efficiency of several commercial and laboratory catalysts in the catalytic ozonation of a simulated phenolic wastewater was tested. Experiments involving three ceria-based catalysts prepared in our laboratory, namely, Co−Ce−O (70/30), Ag−Ce−O (70/30), and Mn−Ce−O (70/30), were compared with those involving commercially available catalysts, namely, G66A (CuO−ZnO/Al2O3), N-150 (Fe2O3−MnOx), SG2216 (CuO−MnOx/Al2O3), and N-140 (CuO−MnOx). Of these, Mn−Ce−O (70/30) was found to be an interesting alternative because 80% of the total organic carbon was removed after 120 min of oxidation. The biodegradability of the simulated wastewater was assessed by measuring the ratio BOD5/COD before and after each treatment. Single and catalytic ozonation over Ag−Ce−O led to a less biodegradable effluent, whereas the rest of the catalytic systems truly enhanced the biodegradability of the simulated wastewater. Trends in the concentrations of some intermediates and the pH profiles were also analyzed for single and catalytic ozonation over Mn−Ce−O (70/30).En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8006209 Exemplaires
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Titre : Modeling ideal and nonideal hydrocracking of paraffins using the single-event lumped parameter hybrid (SELPH) model Type de document : texte imprimé Auteurs : Juan C. Chavarría-Hernández, Auteur ; Jorge Ramírez, Auteur Année de publication : 2009 Article en page(s) : p. 1203–1207 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hydrocracking Oil industrial SELPH model kinetic Résumé : The SELPH (single-event lumped parameter hybrid) model previously developed was used to simulate hydroconversion of n-octane and n-undecane over a wide range of operating conditions, in order to cover both ideal and nonideal hydrocracking behavior. The fundamental kinetic parameters used in the simulations were estimated previously from n-octane hydroconversion experimental data. Results of simulations demonstrate that predictions of the model for the effect of (i) operating pressure, (ii) reaction temperature, (iii) chain length of feed hydrocarbon, and (iv) hydrogen-to-hydrocarbon inlet molar ratio on the ideal (and nonideal) character of hydrocracking are in complete agreement with the general trends reported in the literature. The model allowed identification of intervals of the operating variables in which product selectivities are a unique function of total conversion, i.e., an ideal hydrocracking region, while, in the region of nonideal hydrocracking, the model accurately describes the changes of product selectivities as a function of operating conditions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800639n
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1203–1207[article] Modeling ideal and nonideal hydrocracking of paraffins using the single-event lumped parameter hybrid (SELPH) model [texte imprimé] / Juan C. Chavarría-Hernández, Auteur ; Jorge Ramírez, Auteur . - 2009 . - p. 1203–1207.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1203–1207
Mots-clés : Hydrocracking Oil industrial SELPH model kinetic Résumé : The SELPH (single-event lumped parameter hybrid) model previously developed was used to simulate hydroconversion of n-octane and n-undecane over a wide range of operating conditions, in order to cover both ideal and nonideal hydrocracking behavior. The fundamental kinetic parameters used in the simulations were estimated previously from n-octane hydroconversion experimental data. Results of simulations demonstrate that predictions of the model for the effect of (i) operating pressure, (ii) reaction temperature, (iii) chain length of feed hydrocarbon, and (iv) hydrogen-to-hydrocarbon inlet molar ratio on the ideal (and nonideal) character of hydrocracking are in complete agreement with the general trends reported in the literature. The model allowed identification of intervals of the operating variables in which product selectivities are a unique function of total conversion, i.e., an ideal hydrocracking region, while, in the region of nonideal hydrocracking, the model accurately describes the changes of product selectivities as a function of operating conditions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800639n Exemplaires
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Titre : Catalytic supercritical water oxidation for the destruction of quinoline over MnO2/CuO mixed catalyst Type de document : texte imprimé Auteurs : Mauricio J. Angeles-Hernández, Auteur ; Gary A. Leeke, Auteur ; Regina C. D. Santos, Auteur Année de publication : 2009 Article en page(s) : p. 1208–1214 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Catalytic Quinoline water oxidation Résumé : This article presents the results of the oxidation at supercritical conditions of a nonbiodegradable and highly stable nitrogen containing heterocyclic organic compound (quinoline) over a mixed catalyst in a tubular fixed-bed reactor. The effect of operating conditions namely temperature, pressure, oxygen concentration, and initial quinoline concentration were studied to evaluate their effect on the removal of the organic compound. The results showed that the catalytic reaction depended strongly on temperature and pressure; nevertheless it was very efficient at milder operating conditions close to the critical point of water. A power-law kinetic model was proposed to quantify the catalytic oxidation of quinoline. Three Langmuir−Hinshelwood−Hougen−Watson reaction rates models were also explored to fit the experimental data. However, the kinetic data were better represented by the power-law kinetic model. The catalyst was able to maintain its activity, and thus it can be used as an alternative to reduce the severity of the process. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8006402
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1208–1214[article] Catalytic supercritical water oxidation for the destruction of quinoline over MnO2/CuO mixed catalyst [texte imprimé] / Mauricio J. Angeles-Hernández, Auteur ; Gary A. Leeke, Auteur ; Regina C. D. Santos, Auteur . - 2009 . - p. 1208–1214.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1208–1214
Mots-clés : Catalytic Quinoline water oxidation Résumé : This article presents the results of the oxidation at supercritical conditions of a nonbiodegradable and highly stable nitrogen containing heterocyclic organic compound (quinoline) over a mixed catalyst in a tubular fixed-bed reactor. The effect of operating conditions namely temperature, pressure, oxygen concentration, and initial quinoline concentration were studied to evaluate their effect on the removal of the organic compound. The results showed that the catalytic reaction depended strongly on temperature and pressure; nevertheless it was very efficient at milder operating conditions close to the critical point of water. A power-law kinetic model was proposed to quantify the catalytic oxidation of quinoline. Three Langmuir−Hinshelwood−Hougen−Watson reaction rates models were also explored to fit the experimental data. However, the kinetic data were better represented by the power-law kinetic model. The catalyst was able to maintain its activity, and thus it can be used as an alternative to reduce the severity of the process. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8006402 Exemplaires
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Titre : Evaluation of vanadium-phosphorus oxide (VPO) catalysts for the oxidative dehydrogenation of propane Type de document : texte imprimé Auteurs : Salvador Arias-Pérez, Auteur ; Ricardo García-Alamilla, Auteur Année de publication : 2009 Article en page(s) : p 1215–1219 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Vanadium -- oxide Phosphorus Dehydrogenation Résumé : The catalytic activity of vanadium−phosphorus oxide (VPO) catalysts for the oxidative dehydrogenation of propane is analyzed. Two series of catalysts were synthesized in an organic medium with P/V molar ratios of 0.9 and 1.1. These materials were characterized by X-ray diffraction, N2 physisorption, NH3 adsorption microcalorimetry, decomposition of 2-propanol, and redox titration. The crystalline phase (VO)2P2O7, with a tetravalent vanadium oxidation state, was observed in all the catalysts. As a result of thermal treatment, their crystal size increased, which suggests more crystallinity, and a slight increment in the surface area (31−39 m2/g) also was observed. The microcalorimetry studies of the vanadium phosphates showed heats of adsorption for NH3 between 260 and 60 kJ/mol that can be associated with strong and medium strength acid sites, which are responsible for promoting the selectivity toward oxygenated products and COx; furthermore, it was found that larger crystallographic disorder favors the selectivity to propylene up to an 8.82% over a VPO that has been calcined at 673 K and has a P/V molar ratio of 1.1. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800649z
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p 1215–1219[article] Evaluation of vanadium-phosphorus oxide (VPO) catalysts for the oxidative dehydrogenation of propane [texte imprimé] / Salvador Arias-Pérez, Auteur ; Ricardo García-Alamilla, Auteur . - 2009 . - p 1215–1219.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p 1215–1219
Mots-clés : Vanadium -- oxide Phosphorus Dehydrogenation Résumé : The catalytic activity of vanadium−phosphorus oxide (VPO) catalysts for the oxidative dehydrogenation of propane is analyzed. Two series of catalysts were synthesized in an organic medium with P/V molar ratios of 0.9 and 1.1. These materials were characterized by X-ray diffraction, N2 physisorption, NH3 adsorption microcalorimetry, decomposition of 2-propanol, and redox titration. The crystalline phase (VO)2P2O7, with a tetravalent vanadium oxidation state, was observed in all the catalysts. As a result of thermal treatment, their crystal size increased, which suggests more crystallinity, and a slight increment in the surface area (31−39 m2/g) also was observed. The microcalorimetry studies of the vanadium phosphates showed heats of adsorption for NH3 between 260 and 60 kJ/mol that can be associated with strong and medium strength acid sites, which are responsible for promoting the selectivity toward oxygenated products and COx; furthermore, it was found that larger crystallographic disorder favors the selectivity to propylene up to an 8.82% over a VPO that has been calcined at 673 K and has a P/V molar ratio of 1.1. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800649z Exemplaires
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Titre : Tracking catalyst activity during fluidized-bed catalytic cracking Type de document : texte imprimé Auteurs : Gladys Jiménez-García, Auteur ; Ricardo Aguilar-López, Auteur ; Elizabeth León-Becerril, Auteur Année de publication : 2009 Article en page(s) : p. 1220–1227 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Chimie industrial Catalytic cracking Industrial reactor Résumé : Fluidized-bed catalytic cracking (FCC) of vacuum gas oils, which produces aggregated value liquid fuels such as gasoline and liquid petroleum gas, is an important process in petroleum refining. Cracking reactions take place in risers, which are transported solid bed devices. In order to model risers it is necessary to develop kinetic schemes; however, complex catalyst deactivation, reaction paths, and nonisothermal behavior of these adiabatic units make it difficult to propose accurate schemes. The main mechanism of catalyst deactivation has been under research for more than 60 years, being related to coke formation during FCC reactions and the consequent active sites coverage and catalyst’s pore blockage. Although it is usual to model these phenomena as a function of “time-on-stream”, it is possible to explain it in terms of effectiveness factors. If pore blockage is noticeable, then different activity related to each reactant is reflected by the relative magnitude of individual effective diffusion coefficients; unfortunately, these transport parameters are difficult to measure. In this work, a theoretical methodology based on the comparison of yield to products from different feed stocks is proposed to track catalyst activity dynamics; estimation functions are based on fundamental transport parameters, mainly effective diffusion, inside the catalyst particle. Experimental results obtained in microactivity tests and industrial reactors are used to adjust values of catalytic activity and probe the approach proposed; simulation results for an industrial riser reactor confirm the satisfactory description of the activity profiles En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800650y
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1220–1227[article] Tracking catalyst activity during fluidized-bed catalytic cracking [texte imprimé] / Gladys Jiménez-García, Auteur ; Ricardo Aguilar-López, Auteur ; Elizabeth León-Becerril, Auteur . - 2009 . - p. 1220–1227.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1220–1227
Mots-clés : Chimie industrial Catalytic cracking Industrial reactor Résumé : Fluidized-bed catalytic cracking (FCC) of vacuum gas oils, which produces aggregated value liquid fuels such as gasoline and liquid petroleum gas, is an important process in petroleum refining. Cracking reactions take place in risers, which are transported solid bed devices. In order to model risers it is necessary to develop kinetic schemes; however, complex catalyst deactivation, reaction paths, and nonisothermal behavior of these adiabatic units make it difficult to propose accurate schemes. The main mechanism of catalyst deactivation has been under research for more than 60 years, being related to coke formation during FCC reactions and the consequent active sites coverage and catalyst’s pore blockage. Although it is usual to model these phenomena as a function of “time-on-stream”, it is possible to explain it in terms of effectiveness factors. If pore blockage is noticeable, then different activity related to each reactant is reflected by the relative magnitude of individual effective diffusion coefficients; unfortunately, these transport parameters are difficult to measure. In this work, a theoretical methodology based on the comparison of yield to products from different feed stocks is proposed to track catalyst activity dynamics; estimation functions are based on fundamental transport parameters, mainly effective diffusion, inside the catalyst particle. Experimental results obtained in microactivity tests and industrial reactors are used to adjust values of catalytic activity and probe the approach proposed; simulation results for an industrial riser reactor confirm the satisfactory description of the activity profiles En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800650y Exemplaires
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Titre : Effect of liquid quenching on hydroprocessing of heavy crude oils in a fixed-bed reactor system Type de document : texte imprimé Auteurs : Anton Alvarez, Auteur ; Jorge Ancheyta, Auteur Année de publication : 2009 Article en page(s) : p. 1228–1236 Note générale : Cemical engineering Langues : Anglais (eng) Mots-clés : Oil Gas Liquid Quenching Hydroprocessing Résumé :
The effect of liquid quenching during the hydroprocessing of a heavy crude oil in a fixed-bed reactor system was explored. Experiments were carried out at various operating conditions in a pilot plant equipped with two fixed-bed reactors in series loaded with a triple catalyst system and necessary hardware for injecting quench fluids between reactors. The feed and quench liquid were prepared by splitting a heavy crude oil into two fractions, called light and heavy fractions. The heavy fraction was used as the feed to the reactors, whereas the light fraction was injected between reactors as the quenching liquid. To establish a reference case, a conventional hydrogen quenching scheme was also evaluated by injecting hydrogen instead of the light fraction. It was observed that hydrogen quenching produced only marginally better quality because of a more favorable H2/oil profile. Yet, it was determined that this approach (hydrogen quenching) requires the handling of large volumes of gas, which increases compressor capacity and equipment size. Liquid quenching, on the other hand, decreases the reaction severity by increasing the liquid hourly space velocity (LHSV), which affects product quality although not significantly. Compared with hydrogen quenching, liquid quenching dramatically reduces the quench volumetric rate and consequently compression costs, which makes this approach an economically attractive option for industrial application.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800686g
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1228–1236[article] Effect of liquid quenching on hydroprocessing of heavy crude oils in a fixed-bed reactor system [texte imprimé] / Anton Alvarez, Auteur ; Jorge Ancheyta, Auteur . - 2009 . - p. 1228–1236.
Cemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1228–1236
Mots-clés : Oil Gas Liquid Quenching Hydroprocessing Résumé :
The effect of liquid quenching during the hydroprocessing of a heavy crude oil in a fixed-bed reactor system was explored. Experiments were carried out at various operating conditions in a pilot plant equipped with two fixed-bed reactors in series loaded with a triple catalyst system and necessary hardware for injecting quench fluids between reactors. The feed and quench liquid were prepared by splitting a heavy crude oil into two fractions, called light and heavy fractions. The heavy fraction was used as the feed to the reactors, whereas the light fraction was injected between reactors as the quenching liquid. To establish a reference case, a conventional hydrogen quenching scheme was also evaluated by injecting hydrogen instead of the light fraction. It was observed that hydrogen quenching produced only marginally better quality because of a more favorable H2/oil profile. Yet, it was determined that this approach (hydrogen quenching) requires the handling of large volumes of gas, which increases compressor capacity and equipment size. Liquid quenching, on the other hand, decreases the reaction severity by increasing the liquid hourly space velocity (LHSV), which affects product quality although not significantly. Compared with hydrogen quenching, liquid quenching dramatically reduces the quench volumetric rate and consequently compression costs, which makes this approach an economically attractive option for industrial application.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800686g Exemplaires
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Titre : Brønsted acidity of MgO induced by H2S adsorption Type de document : texte imprimé Auteurs : L. Oliviero, Auteur ; H. Leclerc, Auteur ; O. V. Manoilova, Auteur ; V. Blasin-Aube, Auteur Année de publication : 2009 Article en page(s) : p. 1237–1241 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Brønsted acids Résumé : The effect of H2S upon the acidity of the MgO surface has been investigated using FTIR spectra of adsorbed dimethyl pyridine (2,6-DMP) and CO as test molecules. In the presence of weakly bound H2S, the spectra of 2,6-DMP reveal Brønsted acidity. Adsorption of CO perturbed OH groups from MgO only in the presence of H2S or of aprotic molecules such as CO2 or SO2. This infers that these are the surface OH groups activated by acidic molecules which act as the source of protons. Thus, weak adsorption of acidic compounds, such as H2S, SO2, or CO2, can lead to dramatic enhancement of the acidity of the MgO surface. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800768a
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1237–1241[article] Brønsted acidity of MgO induced by H2S adsorption [texte imprimé] / L. Oliviero, Auteur ; H. Leclerc, Auteur ; O. V. Manoilova, Auteur ; V. Blasin-Aube, Auteur . - 2009 . - p. 1237–1241.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1237–1241
Mots-clés : Brønsted acids Résumé : The effect of H2S upon the acidity of the MgO surface has been investigated using FTIR spectra of adsorbed dimethyl pyridine (2,6-DMP) and CO as test molecules. In the presence of weakly bound H2S, the spectra of 2,6-DMP reveal Brønsted acidity. Adsorption of CO perturbed OH groups from MgO only in the presence of H2S or of aprotic molecules such as CO2 or SO2. This infers that these are the surface OH groups activated by acidic molecules which act as the source of protons. Thus, weak adsorption of acidic compounds, such as H2S, SO2, or CO2, can lead to dramatic enhancement of the acidity of the MgO surface. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800768a Exemplaires
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Titre : Effect of the incorporation of Al, Ti, and Zr on the cracking and hydrodesulfurization activity of NiMo/SBA-15 catalysts Type de document : texte imprimé Auteurs : P. Rayo, Auteur ; J. Ramírez, Auteur ; Jorge Ancheyta, Auteur Année de publication : 2009 Article en page(s) : p. 1242–1248 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Sulfur Hydrodesulfurization NiMo catalysts Résumé :
The hydrodesulfurization and cracking activity of NiMo sulfided catalysts supported on Al-, Ti-, and Zr-modified SBA-15 was measured using the HDS of thiophene and cracking of cumene as model reactions. The results were used to analyze the effect of each heteroatom on the two reactions, and the existence of a relationship between HDS activity and the catalysts acid properties. The HDS activity of sulfided NiMo catalysts supported on Al-, Ti-, or Zr-modified SBA-15 depends significantly on the nature of the heteroatom used to modify the SBA-15 support. The HDS activity trend displayed by the catalysts was NiMo/Al20-SBA-15 > NiMo/Ti20-SBA-15 > NiMo/Zr20-SBA-15. This trend was similar for the cumene cracking reaction. The results indicate that Brønsted acidity favors hydrodesulfurization.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800862a
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1242–1248[article] Effect of the incorporation of Al, Ti, and Zr on the cracking and hydrodesulfurization activity of NiMo/SBA-15 catalysts [texte imprimé] / P. Rayo, Auteur ; J. Ramírez, Auteur ; Jorge Ancheyta, Auteur . - 2009 . - p. 1242–1248.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1242–1248
Mots-clés : Sulfur Hydrodesulfurization NiMo catalysts Résumé :
The hydrodesulfurization and cracking activity of NiMo sulfided catalysts supported on Al-, Ti-, and Zr-modified SBA-15 was measured using the HDS of thiophene and cracking of cumene as model reactions. The results were used to analyze the effect of each heteroatom on the two reactions, and the existence of a relationship between HDS activity and the catalysts acid properties. The HDS activity of sulfided NiMo catalysts supported on Al-, Ti-, or Zr-modified SBA-15 depends significantly on the nature of the heteroatom used to modify the SBA-15 support. The HDS activity trend displayed by the catalysts was NiMo/Al20-SBA-15 > NiMo/Ti20-SBA-15 > NiMo/Zr20-SBA-15. This trend was similar for the cumene cracking reaction. The results indicate that Brønsted acidity favors hydrodesulfurization.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800862a Exemplaires
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Titre : Characterization and photocatalytic performance of tin oxide Type de document : texte imprimé Auteurs : D. Solís-Casados, Auteur ; E. Vigueras-Santiago, Auteur ; S. Hernández-López, Auteur Année de publication : 2009 Article en page(s) : p. 1249–1252 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Oxide Tin oxide -- photocatalytic Résumé : Crystalline tin oxide was prepared by using the method of thermal decomposition of stannic chloride pentahydrate. Decomposition process was studied by thermogravimetric analysis and differential scanning calorimetry. This precursor salt was thermally treated at 800 °C during 4 hours to obtain a crystallite size similar to the reference sample. The crystallite size obtained for the as-prepared sample was 25 nm. For comparison purposes Titania P25 from Degussa Co. (crystallite size of 30 nm) was used as the reference sample. The as-obtained sample was characterized by the X-ray powder diffraction technique and infrared spectroscopy. The results indicate that SnO2 was obtained in the crystalline cassiterite phase. N2 physisorption measurements were carried out to determine the textural properties of the obtained SnO2. Methylene blue photodegradation in the presence of the SnO2 catalyst was evaluated in a preliminary way monitoring the absorbance spectrum after the UV irradiation experiments were done (lamp emitting at 254 nm). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800604u
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1249–1252[article] Characterization and photocatalytic performance of tin oxide [texte imprimé] / D. Solís-Casados, Auteur ; E. Vigueras-Santiago, Auteur ; S. Hernández-López, Auteur . - 2009 . - p. 1249–1252.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1249–1252
Mots-clés : Oxide Tin oxide -- photocatalytic Résumé : Crystalline tin oxide was prepared by using the method of thermal decomposition of stannic chloride pentahydrate. Decomposition process was studied by thermogravimetric analysis and differential scanning calorimetry. This precursor salt was thermally treated at 800 °C during 4 hours to obtain a crystallite size similar to the reference sample. The crystallite size obtained for the as-prepared sample was 25 nm. For comparison purposes Titania P25 from Degussa Co. (crystallite size of 30 nm) was used as the reference sample. The as-obtained sample was characterized by the X-ray powder diffraction technique and infrared spectroscopy. The results indicate that SnO2 was obtained in the crystalline cassiterite phase. N2 physisorption measurements were carried out to determine the textural properties of the obtained SnO2. Methylene blue photodegradation in the presence of the SnO2 catalyst was evaluated in a preliminary way monitoring the absorbance spectrum after the UV irradiation experiments were done (lamp emitting at 254 nm). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800604u Exemplaires
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Titre : Removal of biorefractory compounds in industrial wastewater by chemical and electrochemical pretreatments Type de document : texte imprimé Auteurs : Carlos Barrera-Díaz, Auteur ; Ivonne Linares-Hernandez, Auteur ; Gabriela Roa-Morales, Auteur Année de publication : 2009 Article en page(s) : p. 1253–1258 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Industrial wastewater -- Chemical pretreatments Electrochemical Biological treatment Résumé : The goal of this research was to investigate the effectiveness of chemical and electrochemical pretreatments in removing biorefractory compounds from a complex industrial wastewater. The presence of recalcitrant compounds in wastewater reduces the effectiveness of traditional biological treatments; in this case, the COD reduction was around 30%. Therefore, some pretreatments are required to eliminate the toxic substances and improve the biological efficiency. Chemical coagulation was evaluated using the standard jar testing technique with aluminum and iron sulfates and aluminum polyhydroxychloride (PAC). The best pollutant reduction was obtained when 4 mL dm−3 of PAC was added to the industrial wastewater. At the same time, a batch aluminum electrochemical reactor was used, and better COD and color reductions were obtained as compared to those obtained with the chemical method. After being subjected to the pretreatment, the wastewater was introduced into a laboratory-scale biological reactor in which the COD reduction was monitored, and a global reduction of 68% was obtained using the electrochemical + biological method. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800560n
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1253–1258[article] Removal of biorefractory compounds in industrial wastewater by chemical and electrochemical pretreatments [texte imprimé] / Carlos Barrera-Díaz, Auteur ; Ivonne Linares-Hernandez, Auteur ; Gabriela Roa-Morales, Auteur . - 2009 . - p. 1253–1258.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1253–1258
Mots-clés : Industrial wastewater -- Chemical pretreatments Electrochemical Biological treatment Résumé : The goal of this research was to investigate the effectiveness of chemical and electrochemical pretreatments in removing biorefractory compounds from a complex industrial wastewater. The presence of recalcitrant compounds in wastewater reduces the effectiveness of traditional biological treatments; in this case, the COD reduction was around 30%. Therefore, some pretreatments are required to eliminate the toxic substances and improve the biological efficiency. Chemical coagulation was evaluated using the standard jar testing technique with aluminum and iron sulfates and aluminum polyhydroxychloride (PAC). The best pollutant reduction was obtained when 4 mL dm−3 of PAC was added to the industrial wastewater. At the same time, a batch aluminum electrochemical reactor was used, and better COD and color reductions were obtained as compared to those obtained with the chemical method. After being subjected to the pretreatment, the wastewater was introduced into a laboratory-scale biological reactor in which the COD reduction was monitored, and a global reduction of 68% was obtained using the electrochemical + biological method. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800560n Exemplaires
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Titre : On the multiplicities of a catalytic distillation column for the deep hydrodesulfurization of light gas oil Type de document : texte imprimé Auteurs : A. Rosales-Quintero, Auteur ; F. D. Vargas-Villamil, Auteur Année de publication : 2009 Article en page(s) : p. 1259–1269 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Gas Oil Catalytic distillation Hydrodesulfurization Résumé :
Catalytic distillation integrates the reaction and separation into a single unit. Nevertheless, this integration leads to complex open-loop behaviors, as a consequence of nonlinear interactions. As a result, multiplicities and trajectories with complex attracting sets may arise. Multiplicities must be considered during design, operation, and control, because a process with multiplicities may be difficult to control and operate. In this work, the changes in the topological structure of the solutions of a light-gas-oil deep-hydrodesulfurization one-bed catalytic distillation column are studied. A cost-optimal operating point is chosen as a base case. It is obtained by minimizing the total annual cost, while keeping the total sulfur concentration less than 15 ppm. This design is studied to identify the operating region where multiplicities arise. A connection between operability (pressure) and design (catalyst mass) was made and a rich nonlinear behavior was found (i.e., isola branches, criss-cross patterns, cusp bifurcations, input multiplicities, output multiplicities, and input−output multiplicities). Bifurcation diagrams are presented for the most important design and control/operating variables. Yet, no multiplicity was found near the cost-optimal operating point; thus, its operation and control should not be a problem.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800586c
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1259–1269[article] On the multiplicities of a catalytic distillation column for the deep hydrodesulfurization of light gas oil [texte imprimé] / A. Rosales-Quintero, Auteur ; F. D. Vargas-Villamil, Auteur . - 2009 . - p. 1259–1269.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1259–1269
Mots-clés : Gas Oil Catalytic distillation Hydrodesulfurization Résumé :
Catalytic distillation integrates the reaction and separation into a single unit. Nevertheless, this integration leads to complex open-loop behaviors, as a consequence of nonlinear interactions. As a result, multiplicities and trajectories with complex attracting sets may arise. Multiplicities must be considered during design, operation, and control, because a process with multiplicities may be difficult to control and operate. In this work, the changes in the topological structure of the solutions of a light-gas-oil deep-hydrodesulfurization one-bed catalytic distillation column are studied. A cost-optimal operating point is chosen as a base case. It is obtained by minimizing the total annual cost, while keeping the total sulfur concentration less than 15 ppm. This design is studied to identify the operating region where multiplicities arise. A connection between operability (pressure) and design (catalyst mass) was made and a rich nonlinear behavior was found (i.e., isola branches, criss-cross patterns, cusp bifurcations, input multiplicities, output multiplicities, and input−output multiplicities). Bifurcation diagrams are presented for the most important design and control/operating variables. Yet, no multiplicity was found near the cost-optimal operating point; thus, its operation and control should not be a problem.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800586c Exemplaires
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Titre : Simultaneous oxygen and carbon variation within an RBC biofilm as function of different operating conditions Type de document : texte imprimé Auteurs : Sergio A. Martinez-Delgadillo, Auteur ; Denis Cantú-Lozano, Auteur ; Carlos Montalvo, Auteur Année de publication : 2009 Article en page(s) : p. 1270–1276 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Biological contactors Biofilm Oxygen Carbon Résumé :
In this work, a model that considers the change in biofilm density at different biofilm depths was applied. Two correlations, describing the variations of the oxygen and substrate effective diffusivities as functions of the biofilm density and depth, were introduced. The model was validated with experimental data of oxygen concentrations measured with a microelectrode at different biofilm depths in a laboratory-scale rotating biological contactor (RBC) system at different rotational speeds (1.25, 2.75, and 5.25 rpm.), using municipal wastewater. The oxygen and substrate concentration profiles depend on the position on the biodisk. Comparisons between the COD and oxygen concentration profiles obtained with the model and those obtained considering the microorganism density and diffusivities to be constant were performed. The effects of the biokinetic parameters μmax, KS, and KO2 on the COD and oxygen concentration profiles inside the biofilm were tested.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8005885
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1270–1276[article] Simultaneous oxygen and carbon variation within an RBC biofilm as function of different operating conditions [texte imprimé] / Sergio A. Martinez-Delgadillo, Auteur ; Denis Cantú-Lozano, Auteur ; Carlos Montalvo, Auteur . - 2009 . - p. 1270–1276.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1270–1276
Mots-clés : Biological contactors Biofilm Oxygen Carbon Résumé :
In this work, a model that considers the change in biofilm density at different biofilm depths was applied. Two correlations, describing the variations of the oxygen and substrate effective diffusivities as functions of the biofilm density and depth, were introduced. The model was validated with experimental data of oxygen concentrations measured with a microelectrode at different biofilm depths in a laboratory-scale rotating biological contactor (RBC) system at different rotational speeds (1.25, 2.75, and 5.25 rpm.), using municipal wastewater. The oxygen and substrate concentration profiles depend on the position on the biodisk. Comparisons between the COD and oxygen concentration profiles obtained with the model and those obtained considering the microorganism density and diffusivities to be constant were performed. The effects of the biokinetic parameters μmax, KS, and KO2 on the COD and oxygen concentration profiles inside the biofilm were tested.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8005885 Exemplaires
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Titre : Ionic-liquid-phase hydrolysis of pine wood Type de document : texte imprimé Auteurs : Carsten Sievers, Auteur ; Mariefel B. Valenzuela-Olarte, Auteur ; Teresita Marzialetti, Auteur ; Ildar Musin, Auteur Année de publication : 2009 Article en page(s) : p. 1277–1286 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ions Ionic liquid Hemicellulose Cellulose -- Depolymerization Hydrolysis Résumé :
Depolymerization of cellulose and hemicellulose from loblolly pine wood is studied in the ionic liquid 1-butyl-3-methylimidazolium chloride, which is capable of dissolving carbohydrates and lignin. In the presence of an acid catalyst, the carbohydrate fraction is converted into water-soluble products under milder conditions than reported for similar reactions in the aqueous phase. The water-soluble products included monosaccharides, oligosaccharides, furfural, and 5-hydroxymethylfurfural (HMF). The lignin fraction is recovered as a solid residue. It is found by 13C CP MAS NMR spectroscopy that chemical modifications of lignin occurred only to a very moderate extent. The influence of the reaction temperature, water content, and acid concentration is investigated. In particular, the presence of water is found to reduce the solubility of carbohydrate but also to be required for its conversion. Under harsh conditions (high temperature, high acid concentration), solid degradation products, so-called humins, form. The main building blocks of humins are sugars that are linked by additional components forming linkages that are more resistant to hydrolysis than glycosidic bonds in carbohydrates.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801174x
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1277–1286[article] Ionic-liquid-phase hydrolysis of pine wood [texte imprimé] / Carsten Sievers, Auteur ; Mariefel B. Valenzuela-Olarte, Auteur ; Teresita Marzialetti, Auteur ; Ildar Musin, Auteur . - 2009 . - p. 1277–1286.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1277–1286
Mots-clés : Ions Ionic liquid Hemicellulose Cellulose -- Depolymerization Hydrolysis Résumé :
Depolymerization of cellulose and hemicellulose from loblolly pine wood is studied in the ionic liquid 1-butyl-3-methylimidazolium chloride, which is capable of dissolving carbohydrates and lignin. In the presence of an acid catalyst, the carbohydrate fraction is converted into water-soluble products under milder conditions than reported for similar reactions in the aqueous phase. The water-soluble products included monosaccharides, oligosaccharides, furfural, and 5-hydroxymethylfurfural (HMF). The lignin fraction is recovered as a solid residue. It is found by 13C CP MAS NMR spectroscopy that chemical modifications of lignin occurred only to a very moderate extent. The influence of the reaction temperature, water content, and acid concentration is investigated. In particular, the presence of water is found to reduce the solubility of carbohydrate but also to be required for its conversion. Under harsh conditions (high temperature, high acid concentration), solid degradation products, so-called humins, form. The main building blocks of humins are sugars that are linked by additional components forming linkages that are more resistant to hydrolysis than glycosidic bonds in carbohydrates.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801174x Exemplaires
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Titre : Hydrogen bonding and interaction in the absorption processes of sulfur dioxide in ethylene glycol + water binary desulfurization system Type de document : texte imprimé Auteurs : Jianbin Zhang, Auteur ; Pengyan Zhang, Auteur ; Fang Han, Auteur Année de publication : 2009 Article en page(s) : p. 1287–1291 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Sulfur Dioxide Ethylene Glycol Hydrogen Desulfurization System Spectroscopy Résumé : In this work, ethylene glycol (EG) (1) + water (2) solutions (EGWs) were used as the promising medium for the absorption and desorption processes of SO2. Desorption data showed that SO2 can be desorbed easily from EGWs + SO2 at 333 K. Φ1 = 70−90% (volume fraction of EG in EGWs) were considered as reasonable compositions of desulfurization solution. Considering the industrial flue gas desulfurization (FGD) processes, Φ1 = 80% EGW (approximately 0.5 molar fraction of EG) was confirmed as the optimum composition of desulfurization solution. When conventional UV, FTIR, and 1H NMR spectroscopic techniques were used for inspection of spectral changes of SO2 in EGWs, the spectral results suggest that SO2 can interact with EG by hydrogen bonds. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801544t
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1287–1291[article] Hydrogen bonding and interaction in the absorption processes of sulfur dioxide in ethylene glycol + water binary desulfurization system [texte imprimé] / Jianbin Zhang, Auteur ; Pengyan Zhang, Auteur ; Fang Han, Auteur . - 2009 . - p. 1287–1291.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1287–1291
Mots-clés : Sulfur Dioxide Ethylene Glycol Hydrogen Desulfurization System Spectroscopy Résumé : In this work, ethylene glycol (EG) (1) + water (2) solutions (EGWs) were used as the promising medium for the absorption and desorption processes of SO2. Desorption data showed that SO2 can be desorbed easily from EGWs + SO2 at 333 K. Φ1 = 70−90% (volume fraction of EG in EGWs) were considered as reasonable compositions of desulfurization solution. Considering the industrial flue gas desulfurization (FGD) processes, Φ1 = 80% EGW (approximately 0.5 molar fraction of EG) was confirmed as the optimum composition of desulfurization solution. When conventional UV, FTIR, and 1H NMR spectroscopic techniques were used for inspection of spectral changes of SO2 in EGWs, the spectral results suggest that SO2 can interact with EG by hydrogen bonds. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801544t Exemplaires
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Titre : Pyrolysis of broiler manure : char and product gas characterization Type de document : texte imprimé Auteurs : Isabel M. Lima, Auteur ; Akwasi A. Boateng, Auteur ; K. Thomas Klasson, Auteur Année de publication : 2009 Article en page(s) : p. 1292–1297 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Manure -- Pyrolysis Résumé :
Value-added materials produced from broiler manure can be a renewable alternative to its problematic disposal. Pyrolysis of broiler manure (litter and cake) produces char, bio-oil, and biogas. In this study broiler manure chars were characterized for their ability to adsorb selected metal ions. Char yields for pelletized broiler manure slowly pyrolyzed at 700 and 800 °C for 1 h ranged between 29.6% and 33.5%. Surface areas for the broiler litter and cake decreased with pyrolysis temperature with 238 and 318 m2/g and 199 and 261 m2/g for 700 and 800 °C, respectively. Broiler manure chars removed significantly more metal ions from solution (up to 0.91 mmol/g Cu2+ and 0.96 mmol/g Zn2+) when compared to chars produced from coal, wood, or coconut shells (up to 0.0 mmol/g Cu2+ and 0.10 mmol/g Zn2+). Composition of the biogas generated during fast pyrolysis between 700−900 °C, as a measurement of its energy potential, was also determined. The major components of the noncondensable gas produced during fast pyrolysis of broiler manure, included CO, CO2, low molecular weight hydrocarbon gases, and H2. Except for CO, noncondensable gases increased with pyrolysis temperature.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800989s
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1292–1297[article] Pyrolysis of broiler manure : char and product gas characterization [texte imprimé] / Isabel M. Lima, Auteur ; Akwasi A. Boateng, Auteur ; K. Thomas Klasson, Auteur . - 2009 . - p. 1292–1297.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1292–1297
Mots-clés : Manure -- Pyrolysis Résumé :
Value-added materials produced from broiler manure can be a renewable alternative to its problematic disposal. Pyrolysis of broiler manure (litter and cake) produces char, bio-oil, and biogas. In this study broiler manure chars were characterized for their ability to adsorb selected metal ions. Char yields for pelletized broiler manure slowly pyrolyzed at 700 and 800 °C for 1 h ranged between 29.6% and 33.5%. Surface areas for the broiler litter and cake decreased with pyrolysis temperature with 238 and 318 m2/g and 199 and 261 m2/g for 700 and 800 °C, respectively. Broiler manure chars removed significantly more metal ions from solution (up to 0.91 mmol/g Cu2+ and 0.96 mmol/g Zn2+) when compared to chars produced from coal, wood, or coconut shells (up to 0.0 mmol/g Cu2+ and 0.10 mmol/g Zn2+). Composition of the biogas generated during fast pyrolysis between 700−900 °C, as a measurement of its energy potential, was also determined. The major components of the noncondensable gas produced during fast pyrolysis of broiler manure, included CO, CO2, low molecular weight hydrocarbon gases, and H2. Except for CO, noncondensable gases increased with pyrolysis temperature.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800989s Exemplaires
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Titre : Electrooxidation of brown-colored molasses wastewater. effect of the electrolyte salt on the process efficiency Type de document : texte imprimé Auteurs : P. Cañizares, Auteur ; M. Hernández, Auteur ; M. A. Rodrigo, Auteur Année de publication : 2009 Article en page(s) : p. 1298–1301 Note générale : Chemical engeenering Langues : Anglais (eng) Mots-clés : Electrochemical oxidation Synthetic melanoidin Résumé :
In this work, synthetic melanoidin wastes have been treated with conductive-diamond electrochemical oxidation in a bench-scale plant. The results show a significant influence of the current density and also of the electrolyte salts on the efficiency of the treatment. The electrochemical oxidation of the melanoidins in the presence of carbonate or perchlorate does not lead to the complete mineralization of the organics, but to the accumulation of refractory compounds. Conversely, the oxidation of these synthetic wastes in the presence of chlorine, sulfates, or phosphates yields the complete removal of the chemical oxygen demand and total organic carbon of the wastes. In addition, the efficiency (amount of melanoidin removed per Ah) also depends on the electrolyte salt. Thus, the presence of chloride and phosphate anions allows better results to be obtained. These observations have been explained taking into account the important role of the mediated oxidation carried out by the oxidizing electrogenerated agents (peroxodisulfate, peroxodiphosphate, hypochlorite,...) from the oxidation of the electrolyte salts. The results obtained as a function of the current density also confirm the important role of electrogenerated oxidants on the treatment efficiency.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801038t
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1298–1301[article] Electrooxidation of brown-colored molasses wastewater. effect of the electrolyte salt on the process efficiency [texte imprimé] / P. Cañizares, Auteur ; M. Hernández, Auteur ; M. A. Rodrigo, Auteur . - 2009 . - p. 1298–1301.
Chemical engeenering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1298–1301
Mots-clés : Electrochemical oxidation Synthetic melanoidin Résumé :
In this work, synthetic melanoidin wastes have been treated with conductive-diamond electrochemical oxidation in a bench-scale plant. The results show a significant influence of the current density and also of the electrolyte salts on the efficiency of the treatment. The electrochemical oxidation of the melanoidins in the presence of carbonate or perchlorate does not lead to the complete mineralization of the organics, but to the accumulation of refractory compounds. Conversely, the oxidation of these synthetic wastes in the presence of chlorine, sulfates, or phosphates yields the complete removal of the chemical oxygen demand and total organic carbon of the wastes. In addition, the efficiency (amount of melanoidin removed per Ah) also depends on the electrolyte salt. Thus, the presence of chloride and phosphate anions allows better results to be obtained. These observations have been explained taking into account the important role of the mediated oxidation carried out by the oxidizing electrogenerated agents (peroxodisulfate, peroxodiphosphate, hypochlorite,...) from the oxidation of the electrolyte salts. The results obtained as a function of the current density also confirm the important role of electrogenerated oxidants on the treatment efficiency.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801038t Exemplaires
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Titre : Spectroscopic investigation of alkylcarbonic acid formation and dissociation in CO2-expanded alcohols Type de document : texte imprimé Auteurs : John L. Gohres, Auteur ; Andrew T. Marin, Auteur ; Jie Lu, Auteur Année de publication : 2009 Article en page(s) : p. 1302–1306 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Acids Alkylcarbonic acid Résumé :
We show a technique to measure alkylcarbonic acid (ACA) formation and dissociation constants in CO2-expanded methanol, ethanol, and benzyl alcohol at 25 °C. In these systems, CO2 reacts with alcohols to form an in situ, self-neutralizing acid that exists under CO2 pressure. UV/vis spectroscopy is a noninvasive method to assay proton concentration, and the resulting values of this proton concentration yield effective equilibrium constants, the product of the formation, and dissociation constants. To separate the acid dissociation constant from the formation equilibrium constant, we employ a method using mass balances. From this, we find that methylcarbonic acid has a pKa of 5.7 and the relative ACA strengths are methyl > ethyl > benzyl. This work provides key parameters to design processes and expanded solvents that fully exploit the environmental and processing benefits of ACAs.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8011227
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1302–1306[article] Spectroscopic investigation of alkylcarbonic acid formation and dissociation in CO2-expanded alcohols [texte imprimé] / John L. Gohres, Auteur ; Andrew T. Marin, Auteur ; Jie Lu, Auteur . - 2009 . - p. 1302–1306.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1302–1306
Mots-clés : Acids Alkylcarbonic acid Résumé :
We show a technique to measure alkylcarbonic acid (ACA) formation and dissociation constants in CO2-expanded methanol, ethanol, and benzyl alcohol at 25 °C. In these systems, CO2 reacts with alcohols to form an in situ, self-neutralizing acid that exists under CO2 pressure. UV/vis spectroscopy is a noninvasive method to assay proton concentration, and the resulting values of this proton concentration yield effective equilibrium constants, the product of the formation, and dissociation constants. To separate the acid dissociation constant from the formation equilibrium constant, we employ a method using mass balances. From this, we find that methylcarbonic acid has a pKa of 5.7 and the relative ACA strengths are methyl > ethyl > benzyl. This work provides key parameters to design processes and expanded solvents that fully exploit the environmental and processing benefits of ACAs.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8011227 Exemplaires
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Titre : Simple procedure for optimally scaling-up fine chemical processes. I. practical tools Type de document : texte imprimé Auteurs : Francesco Maestri, Auteur ; Sabrina Copelli, Auteur ; Renato Rota, Auteur Année de publication : 2009 Article en page(s) : p. 1307–1315 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Chemical processes Industrial reactor Résumé :
A simple and general scale-up procedure, based on boundary and temperature diagram safety criteria for exothermic semibatch reactors (SBRs), has been developed. Such a procedure is based on a few graphical correlations that allow end users, dealing with homogeneous as well as heterogeneous SBRs (with or without autocatalytic behavior), an easy selection of safe operating conditions at the laboratory scale and for their scale-up to the industrial one, maximizing at the same time the industrial reactor productivity.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800465d
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1307–1315[article] Simple procedure for optimally scaling-up fine chemical processes. I. practical tools [texte imprimé] / Francesco Maestri, Auteur ; Sabrina Copelli, Auteur ; Renato Rota, Auteur . - 2009 . - p. 1307–1315.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1307–1315
Mots-clés : Chemical processes Industrial reactor Résumé :
A simple and general scale-up procedure, based on boundary and temperature diagram safety criteria for exothermic semibatch reactors (SBRs), has been developed. Such a procedure is based on a few graphical correlations that allow end users, dealing with homogeneous as well as heterogeneous SBRs (with or without autocatalytic behavior), an easy selection of safe operating conditions at the laboratory scale and for their scale-up to the industrial one, maximizing at the same time the industrial reactor productivity.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800465d Exemplaires
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Titre : Simple procedure for optimal scale-up of fine chemical processes. II. nitration of 4-chlorobenzotrifluoride Type de document : texte imprimé Auteurs : Francesco Maestri, Auteur ; Sabrina Copelli, Auteur ; Renato Rota, Auteur Année de publication : 2009 Article en page(s) : p. 1316–1324 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Chemical Processes Industrial reactor Résumé :
In this work, a simple and general procedure for optimally scaling-up exothermic semibatch processes has been applied to the analysis of a nitration reaction performed in the agrochemical industry for the production of an important class of herbicides. Such a reaction is performed in indirectly cooled semibatch reactors in which the species to be nitrated is added to a mixture of sulfuric and nitric acid, forming a heterogeneous (liquid−liquid) system. Adiabatic calorimetric experiments performed in an ARC equipment showed that the reaction in question belongs to the most critical class of exothermic reaction processes, for which maximum attainable temperature due to synthesis reaction (MTSR) is, at the same time, higher than system decomposition temperature and lower than boiling temperature of the reaction mass. It has been verified, through reaction calorimetry experiments (performed in an RC1 equipment), that the optimization−scale-up procedure previously developed allows, with minimum calculation and experimental effort, both for a selection, at laboratory scale, of operating conditions characterized by a rapid coreactant consumption and for their safe scale-up, maximizing industrial reactor productivity.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800466n
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1316–1324[article] Simple procedure for optimal scale-up of fine chemical processes. II. nitration of 4-chlorobenzotrifluoride [texte imprimé] / Francesco Maestri, Auteur ; Sabrina Copelli, Auteur ; Renato Rota, Auteur . - 2009 . - p. 1316–1324.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1316–1324
Mots-clés : Chemical Processes Industrial reactor Résumé :
In this work, a simple and general procedure for optimally scaling-up exothermic semibatch processes has been applied to the analysis of a nitration reaction performed in the agrochemical industry for the production of an important class of herbicides. Such a reaction is performed in indirectly cooled semibatch reactors in which the species to be nitrated is added to a mixture of sulfuric and nitric acid, forming a heterogeneous (liquid−liquid) system. Adiabatic calorimetric experiments performed in an ARC equipment showed that the reaction in question belongs to the most critical class of exothermic reaction processes, for which maximum attainable temperature due to synthesis reaction (MTSR) is, at the same time, higher than system decomposition temperature and lower than boiling temperature of the reaction mass. It has been verified, through reaction calorimetry experiments (performed in an RC1 equipment), that the optimization−scale-up procedure previously developed allows, with minimum calculation and experimental effort, both for a selection, at laboratory scale, of operating conditions characterized by a rapid coreactant consumption and for their safe scale-up, maximizing industrial reactor productivity.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800466n Exemplaires
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Titre : Hydroformylation of 1-butene on Rh catalyst Type de document : texte imprimé Auteurs : Tapio Salmi, Auteur ; Johan Ahlkvist, Auteur ; Andreas Bernas, Auteur Année de publication : 2009 Article en page(s) : p. 1325–1331 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hydroformylation Rhodium catalyst Butene Résumé : Kinetics of homogeneously catalyzed hydroformylation of 1-butene was studied in a pressurized semibatch autoclave reactor. Kinetics was determined for a reaction mixture, which consisted of 1-butene, carbon monoxide, hydrogen, a rhodium-based catalyst, and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate as a solvent. The following reaction parameters were investigated: temperature (70−100 °C), total pressure (1−3 MPa), catalyst concentration (100−200 ppm), catalyst (Rh)-to-ligand ratio, and the initial ratio of the synthesis gas (hydrogen and carbon dioxide) components. The solubility of 1-butene, carbon monoxide, and hydrogen in the solvent was determined by precise pressure and weight measurements and modeled mathematically. The main reaction products were pentanal (P) and 2-methylbutanal (MB), while trace amounts of cis-2- and trans-2-butene were detected as reaction intermediates. The ratio of the main products (P and MB) was practically independent of temperature, but the ligand-to-Rh ratio affected considerably the product distribution: an increasing ratio preferred the formation of pentanal (P). Increasing total pressure diminished the yield of pentanal (P). On the basis of the experimentally recorded kinetic data, a stoichiometric scheme was constructed and simplified. The kinetic data were combined with solubility models, and the parameters of an empirical power-law rate model were determined by nonlinear regression analysis. The kinetic parameters were well identified and physically reasonable being in accordance with qualitative observations. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800215t
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1325–1331[article] Hydroformylation of 1-butene on Rh catalyst [texte imprimé] / Tapio Salmi, Auteur ; Johan Ahlkvist, Auteur ; Andreas Bernas, Auteur . - 2009 . - p. 1325–1331.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1325–1331
Mots-clés : Hydroformylation Rhodium catalyst Butene Résumé : Kinetics of homogeneously catalyzed hydroformylation of 1-butene was studied in a pressurized semibatch autoclave reactor. Kinetics was determined for a reaction mixture, which consisted of 1-butene, carbon monoxide, hydrogen, a rhodium-based catalyst, and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate as a solvent. The following reaction parameters were investigated: temperature (70−100 °C), total pressure (1−3 MPa), catalyst concentration (100−200 ppm), catalyst (Rh)-to-ligand ratio, and the initial ratio of the synthesis gas (hydrogen and carbon dioxide) components. The solubility of 1-butene, carbon monoxide, and hydrogen in the solvent was determined by precise pressure and weight measurements and modeled mathematically. The main reaction products were pentanal (P) and 2-methylbutanal (MB), while trace amounts of cis-2- and trans-2-butene were detected as reaction intermediates. The ratio of the main products (P and MB) was practically independent of temperature, but the ligand-to-Rh ratio affected considerably the product distribution: an increasing ratio preferred the formation of pentanal (P). Increasing total pressure diminished the yield of pentanal (P). On the basis of the experimentally recorded kinetic data, a stoichiometric scheme was constructed and simplified. The kinetic data were combined with solubility models, and the parameters of an empirical power-law rate model were determined by nonlinear regression analysis. The kinetic parameters were well identified and physically reasonable being in accordance with qualitative observations. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800215t Exemplaires
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Titre : Sorption enhanced steam methane reforming process performance and bubbling fluidized bed reactor design analysis by use of a two-fluid model Type de document : texte imprimé Auteurs : Håvard Lindborg, Auteur ; Hugo A. Jakobsen, Auteur Année de publication : 2009 Article en page(s) : p. 1332–1342 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Chemical industrial Petroleum Hydrogen -- production Gas-solid Methane Résumé : This paper discusses simulations of reactive flows in a two-dimensional cylindrical bubbling fluidized bed reactor by using an Eulerian modeling approach. The study is intended to elucidate some aspects of high relevance for the development of novel concepts in the area of hydrogen production by means of steam methane reforming (SMR). The work is initiated with a practical model validation of reactive gas−solid flows with simulations of laboratory-scale experiments of the ozone decomposition reaction. The predicted outlet concentrations for various fluidization velocities are in very good agreement with reported experimental data. Further, investigations of sorption enhanced steam methane reforming (SE-SMR) in bubbling fluidized beds are conducted with lithium zirconate as the CO2 adsorbent. As long as extensive gas mixing is avoided, wide reactors are the most favorable choice for industrial applications since variations in bed diameter have a minor influence on the outlet hydrogen concentration. Running the process at elevated operating pressures and/or higher fluidization velocities requires increased bed heights. The most interesting finding of this work is the demonstration of how internal circulation and spatial temperature variations affect the reactor performance. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800522p
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1332–1342[article] Sorption enhanced steam methane reforming process performance and bubbling fluidized bed reactor design analysis by use of a two-fluid model [texte imprimé] / Håvard Lindborg, Auteur ; Hugo A. Jakobsen, Auteur . - 2009 . - p. 1332–1342.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1332–1342
Mots-clés : Chemical industrial Petroleum Hydrogen -- production Gas-solid Methane Résumé : This paper discusses simulations of reactive flows in a two-dimensional cylindrical bubbling fluidized bed reactor by using an Eulerian modeling approach. The study is intended to elucidate some aspects of high relevance for the development of novel concepts in the area of hydrogen production by means of steam methane reforming (SMR). The work is initiated with a practical model validation of reactive gas−solid flows with simulations of laboratory-scale experiments of the ozone decomposition reaction. The predicted outlet concentrations for various fluidization velocities are in very good agreement with reported experimental data. Further, investigations of sorption enhanced steam methane reforming (SE-SMR) in bubbling fluidized beds are conducted with lithium zirconate as the CO2 adsorbent. As long as extensive gas mixing is avoided, wide reactors are the most favorable choice for industrial applications since variations in bed diameter have a minor influence on the outlet hydrogen concentration. Running the process at elevated operating pressures and/or higher fluidization velocities requires increased bed heights. The most interesting finding of this work is the demonstration of how internal circulation and spatial temperature variations affect the reactor performance. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800522p Exemplaires
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Titre : Prediction of radial distribution function of particles in a gas-solid fluidized bed using discrete hard-sphere model Type de document : texte imprimé Auteurs : Shuyan Wang, Auteur ; Liu Guodong, Auteur ; Huilin Lu, Auteur Année de publication : 2009 Article en page(s) : p. 1343–1352 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Gas-Solid kinetic theory Résumé : Flow behavior of particles in a two-dimensional bubbling fluidized bed is predicted by using discrete hard-sphere model for particle−particle collision. Quantities of radial distribution functions of monosized particles, binary-sized particles, and binary density particles are obtained. Experimentally or theoretically proposed formulations for the radial distribution functions are evaluated based on our numerically predicted results. For monosized particles, the simulated radial distribution functions are in agreement with computed results from both Bagnold equation (1954) and Ma and Ahmadi (1986) equation. For the binary mixture with the different diameters but identical density, the pair radial distribution functions proposed by Boublik (1970) and Mansoori et al. (1971) agree with simulated data. For binary mixture of different densities, a modified equation of the pair radial distribution function is proposed to correlate from our simulation results. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8007049
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1343–1352[article] Prediction of radial distribution function of particles in a gas-solid fluidized bed using discrete hard-sphere model [texte imprimé] / Shuyan Wang, Auteur ; Liu Guodong, Auteur ; Huilin Lu, Auteur . - 2009 . - p. 1343–1352.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1343–1352
Mots-clés : Gas-Solid kinetic theory Résumé : Flow behavior of particles in a two-dimensional bubbling fluidized bed is predicted by using discrete hard-sphere model for particle−particle collision. Quantities of radial distribution functions of monosized particles, binary-sized particles, and binary density particles are obtained. Experimentally or theoretically proposed formulations for the radial distribution functions are evaluated based on our numerically predicted results. For monosized particles, the simulated radial distribution functions are in agreement with computed results from both Bagnold equation (1954) and Ma and Ahmadi (1986) equation. For the binary mixture with the different diameters but identical density, the pair radial distribution functions proposed by Boublik (1970) and Mansoori et al. (1971) agree with simulated data. For binary mixture of different densities, a modified equation of the pair radial distribution function is proposed to correlate from our simulation results. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8007049 Exemplaires
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Titre : Kinetic modeling of temperature dependence of TiCl4 and NH3 surface reaction in trap systems for CVD reactors Type de document : texte imprimé Auteurs : Changhyun Pang, Auteur ; Donghun Jeong, Auteur ; Heeyeop Chae, Auteur Année de publication : 2009 Article en page(s) : p. 1353–1356 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Kinetic Modeling Titanium nitride Résumé :
The chemical vapor deposition (CVD) of titanium nitride (TiN) thin film has been a widely adopted process for the fabrication of diffusion barrier layers in microelectronic fabrication processes. TiCl4(NH3)2 is known to be formed as a solid product in the downstream of the CVD chambers and causes damages to the pumping systems. To prevent such damage, trap systems are installed between the process chamber and pumps. This study focuses on the flow, temperature, and reaction kinetic modeling of the chemical formation of TiCl4(NH3)2 in the trap system by computational fluid dynamics (CFD). The simulation results showed good agreement with the experimental data at temperatures below 120 °C. The deposition rate of TiCl4(NH3)2 is found to increase with increasing temperature of the trap body, and the activation energy determined from the experiments suggests that the chemical vapor deposition of TiCl4(NH3)2 is surface-reaction-controlled.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800729y
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1353–1356[article] Kinetic modeling of temperature dependence of TiCl4 and NH3 surface reaction in trap systems for CVD reactors [texte imprimé] / Changhyun Pang, Auteur ; Donghun Jeong, Auteur ; Heeyeop Chae, Auteur . - 2009 . - p. 1353–1356.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1353–1356
Mots-clés : Kinetic Modeling Titanium nitride Résumé :
The chemical vapor deposition (CVD) of titanium nitride (TiN) thin film has been a widely adopted process for the fabrication of diffusion barrier layers in microelectronic fabrication processes. TiCl4(NH3)2 is known to be formed as a solid product in the downstream of the CVD chambers and causes damages to the pumping systems. To prevent such damage, trap systems are installed between the process chamber and pumps. This study focuses on the flow, temperature, and reaction kinetic modeling of the chemical formation of TiCl4(NH3)2 in the trap system by computational fluid dynamics (CFD). The simulation results showed good agreement with the experimental data at temperatures below 120 °C. The deposition rate of TiCl4(NH3)2 is found to increase with increasing temperature of the trap body, and the activation energy determined from the experiments suggests that the chemical vapor deposition of TiCl4(NH3)2 is surface-reaction-controlled.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800729y Exemplaires
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Titre : Transesterification of sunflower oil with methanol in a microtube reactor Type de document : texte imprimé Auteurs : Guoqing Guan, Auteur ; Katsuki Kusakabe, Auteur ; Kimiko Moriyama, Auteur Année de publication : 2009 Article en page(s) : p. 1357–1363 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Sunflower Oil -- Transesterification Methanol Microtube Reactor Résumé :
Transesterification of sunflower oil with methanol to form fatty acid methyl esters (FAMEs) using a KOH catalyst was performed in a microtube reactor. Oil conversion was significantly affected by microtube length, microtube diameter, the methanol/oil molar ratio, and reaction temperature. Flow patterns were observed in the transparent microtube under different operating conditions and were characterized by optical measurements. The relationship between flow pattern and oil conversion was examined. The flow pattern at the entrance region of the microtube was segmented flow of the methanol and oil phases. As the reaction progressed, fine droplets composed of the produced glycerol and methanol were dispersed and circulated in the oil segments. At a methanol/oil molar ratio of 23.9 at 60 °C, a quasi-homogeneous phase formed approximately 300 mm from the reaction inlet where the oil was completely converted to FAMEs.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800852x
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1357–1363[article] Transesterification of sunflower oil with methanol in a microtube reactor [texte imprimé] / Guoqing Guan, Auteur ; Katsuki Kusakabe, Auteur ; Kimiko Moriyama, Auteur . - 2009 . - p. 1357–1363.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1357–1363
Mots-clés : Sunflower Oil -- Transesterification Methanol Microtube Reactor Résumé :
Transesterification of sunflower oil with methanol to form fatty acid methyl esters (FAMEs) using a KOH catalyst was performed in a microtube reactor. Oil conversion was significantly affected by microtube length, microtube diameter, the methanol/oil molar ratio, and reaction temperature. Flow patterns were observed in the transparent microtube under different operating conditions and were characterized by optical measurements. The relationship between flow pattern and oil conversion was examined. The flow pattern at the entrance region of the microtube was segmented flow of the methanol and oil phases. As the reaction progressed, fine droplets composed of the produced glycerol and methanol were dispersed and circulated in the oil segments. At a methanol/oil molar ratio of 23.9 at 60 °C, a quasi-homogeneous phase formed approximately 300 mm from the reaction inlet where the oil was completely converted to FAMEs.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800852x Exemplaires
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Titre : Kinetics of epoxidation of hydroxyl-terminated polybutadiene with hydrogen peroxide under phase transfer catalysis Type de document : texte imprimé Auteurs : Qingfa Wang, Auteur ; Xiangwen Zhang, Auteur ; Wang, Li, Auteur Année de publication : 2009 Article en page(s) : p. 1364–1371 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hydroxyl-terminated polybutadiene -- epoxidation Hydrogen peroxide Phosphoric acid Ammonium Résumé :
The epoxidation of hydroxyl-terminated polybutadiene (HTPB) via phase transfer catalysis (PTC) using H2O2 as the oxidant and ammonium tungstate hydrate and phosphoric acid as the cocatalysts was successfully carried out in an acidic solution/organic solvent two-phase medium. The microstructures of original and epoxidized HTPB products were confirmed by 1H NMR and 13C NMR. The influence of some process variables such as stirring speed, ammonium tungstate hydrate amount, Aliquat 336 amount, phosphoric acid amount, hydrogen peroxide amount, and reaction temperature on the epoxidation of HTPB were studied in detail. The reactions in organic phase were the rate-controlling steps. Based on the experimental results, a rational PTC mechanism was proposed and a pseudo-steady-state kinetic model was applied to describe the epoxidation of HTPB. The apparent kinetic constants for the three configurations in HTPB under the temperatures of 20−60 °C were determined (kapp,c = (2.7−6.43) × 10−2 min−1, kapp,t = (0.95−4.49) × 10−2 min−1, kapp,v = (0.08−0.65) × 10−2 min−1). The activation energies of cis, trans, and vinyl configurations in the epoxidation of HTPB were 19.72, 31.35, and 90.75 kJ mol−1, respectively. This method (Aliquat 336 as PTC/H2O2/ammonium tungstate hydrate and phosphoric acid as the cocatalysts) was very effective for the epoxidation of HTPB. The chemoselectivity of epoxidation of three configurations in HTPB (cis, trans, and vinyl) was evaluated. The reactivity of double bonds toward epoxidation, depending on the chain microstructure, decreased in the following order: 1,4-cis > 1,4-trans > 1,2-vinyl.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800875h
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1364–1371[article] Kinetics of epoxidation of hydroxyl-terminated polybutadiene with hydrogen peroxide under phase transfer catalysis [texte imprimé] / Qingfa Wang, Auteur ; Xiangwen Zhang, Auteur ; Wang, Li, Auteur . - 2009 . - p. 1364–1371.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1364–1371
Mots-clés : Hydroxyl-terminated polybutadiene -- epoxidation Hydrogen peroxide Phosphoric acid Ammonium Résumé :
The epoxidation of hydroxyl-terminated polybutadiene (HTPB) via phase transfer catalysis (PTC) using H2O2 as the oxidant and ammonium tungstate hydrate and phosphoric acid as the cocatalysts was successfully carried out in an acidic solution/organic solvent two-phase medium. The microstructures of original and epoxidized HTPB products were confirmed by 1H NMR and 13C NMR. The influence of some process variables such as stirring speed, ammonium tungstate hydrate amount, Aliquat 336 amount, phosphoric acid amount, hydrogen peroxide amount, and reaction temperature on the epoxidation of HTPB were studied in detail. The reactions in organic phase were the rate-controlling steps. Based on the experimental results, a rational PTC mechanism was proposed and a pseudo-steady-state kinetic model was applied to describe the epoxidation of HTPB. The apparent kinetic constants for the three configurations in HTPB under the temperatures of 20−60 °C were determined (kapp,c = (2.7−6.43) × 10−2 min−1, kapp,t = (0.95−4.49) × 10−2 min−1, kapp,v = (0.08−0.65) × 10−2 min−1). The activation energies of cis, trans, and vinyl configurations in the epoxidation of HTPB were 19.72, 31.35, and 90.75 kJ mol−1, respectively. This method (Aliquat 336 as PTC/H2O2/ammonium tungstate hydrate and phosphoric acid as the cocatalysts) was very effective for the epoxidation of HTPB. The chemoselectivity of epoxidation of three configurations in HTPB (cis, trans, and vinyl) was evaluated. The reactivity of double bonds toward epoxidation, depending on the chain microstructure, decreased in the following order: 1,4-cis > 1,4-trans > 1,2-vinyl.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800875h Exemplaires
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Titre : Peroxyformic acid formation : a kinetic study Type de document : texte imprimé Auteurs : Paolo De Filippis, Auteur ; Marco Scarsella, Auteur ; Nicola Verdone, Auteur Année de publication : 2009 Article en page(s) : p. 1372–1375 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Peroxyformic acid -- Kinetic study Chemical industry Résumé :
Peroxyformic acid has been recently assuming a growing importance due to the versatile oxidizing properties in several applications in the chemical industry. However, quite surprisingly, a lack of data exists about the kinetics of formation of this compound, an even more singular event considering that the acid, when used, is generally produced in situ via the reaction between formic acid and hydrogen peroxide. This paper is a contribution to fill this gap. A series of batch experiments were carried out to measure the conversion rate in the peroxyformic acid formation reaction in the temperature range 30−60 °C. The results from experiments were successfully interpreted through a kinetic mechanism consisting of the reversible formation of the peroxyformic acid and its irreversible decomposition to CO2 and H2O, both catalyzed by hydrogen ions. With the considered kinetic mechanism, a pre-exponential factor of 13065.1 L6 mol−2 s−1 and an activation energy of 43524.2 J mol−1 were calculated. This last value and enthalpy and entropy of reaction derived from the kinetic data are in quite good accordance with the limited literature data available on this subject.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801163j
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1372–1375[article] Peroxyformic acid formation : a kinetic study [texte imprimé] / Paolo De Filippis, Auteur ; Marco Scarsella, Auteur ; Nicola Verdone, Auteur . - 2009 . - p. 1372–1375.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1372–1375
Mots-clés : Peroxyformic acid -- Kinetic study Chemical industry Résumé :
Peroxyformic acid has been recently assuming a growing importance due to the versatile oxidizing properties in several applications in the chemical industry. However, quite surprisingly, a lack of data exists about the kinetics of formation of this compound, an even more singular event considering that the acid, when used, is generally produced in situ via the reaction between formic acid and hydrogen peroxide. This paper is a contribution to fill this gap. A series of batch experiments were carried out to measure the conversion rate in the peroxyformic acid formation reaction in the temperature range 30−60 °C. The results from experiments were successfully interpreted through a kinetic mechanism consisting of the reversible formation of the peroxyformic acid and its irreversible decomposition to CO2 and H2O, both catalyzed by hydrogen ions. With the considered kinetic mechanism, a pre-exponential factor of 13065.1 L6 mol−2 s−1 and an activation energy of 43524.2 J mol−1 were calculated. This last value and enthalpy and entropy of reaction derived from the kinetic data are in quite good accordance with the limited literature data available on this subject.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801163j Exemplaires
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Titre : Kinetic study of synthesizing dimethoxydiphenylmethane under phase-transfer catalysis and ultrasonic irradiation Type de document : texte imprimé Auteurs : Maw-Ling Wang, Auteur ; Wei-Hung Chen, Auteur Année de publication : 2009 Article en page(s) : p. 1376–1383 Note générale : Chemical enginnering Langues : Anglais (eng) Mots-clés : Dimethoxydiphenylmethane Methanol -- catalytic reaction Résumé :
The synthesis of dimethoxydiphenylmethane (DMODPM) from the reaction of methanol and dichlorodiphenylmethane (DCDPM) was successfully carried out in a liquid−liquid phase-transfer catalytic (LLPTC) reaction assisted by ultrasonic irradiation. Little of the desired product DMODPM was obtained from the reaction in the presence of only potassium hydroxide and quaternary ammonium salts. The production of the DMODPM product was greatly enhanced when the reaction system was irradiated by ultrasonic waves. Two sequential reactions in the organic-phase solution proceed to produce the desired product. However, the second rate of the organic-phase reaction was faster than the first. Therefore, the first intermediate product, chloromethoxydiphenylmethane (CMODPM), was not detected during or after the reaction. A kinetic model was developed based on the experimental data. A pseudo-steady-state hypothesis (PSSH) was employed to describe the characteristic behaviors of the kinetic data. The results were finally described by a pseudo-first-order rate law, from which the apparent rate constant (kapp,1) of the first organic-phase reaction was obtained. The effects of the reaction conditions on the conversion of DCDPM and the reaction rate were investigated in detail, including the agitation speed; the amounts of methanol, DCDPM, water, chlorobenzene, potassium hydroxide, and tetrabutylammonium bromide (TBAB); the ultrasonic power and frequency; the organic solvents; the quaternary ammonium salts; and the temperature. Rational explanations are provided for the experimental results.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8011616
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1376–1383[article] Kinetic study of synthesizing dimethoxydiphenylmethane under phase-transfer catalysis and ultrasonic irradiation [texte imprimé] / Maw-Ling Wang, Auteur ; Wei-Hung Chen, Auteur . - 2009 . - p. 1376–1383.
Chemical enginnering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1376–1383
Mots-clés : Dimethoxydiphenylmethane Methanol -- catalytic reaction Résumé :
The synthesis of dimethoxydiphenylmethane (DMODPM) from the reaction of methanol and dichlorodiphenylmethane (DCDPM) was successfully carried out in a liquid−liquid phase-transfer catalytic (LLPTC) reaction assisted by ultrasonic irradiation. Little of the desired product DMODPM was obtained from the reaction in the presence of only potassium hydroxide and quaternary ammonium salts. The production of the DMODPM product was greatly enhanced when the reaction system was irradiated by ultrasonic waves. Two sequential reactions in the organic-phase solution proceed to produce the desired product. However, the second rate of the organic-phase reaction was faster than the first. Therefore, the first intermediate product, chloromethoxydiphenylmethane (CMODPM), was not detected during or after the reaction. A kinetic model was developed based on the experimental data. A pseudo-steady-state hypothesis (PSSH) was employed to describe the characteristic behaviors of the kinetic data. The results were finally described by a pseudo-first-order rate law, from which the apparent rate constant (kapp,1) of the first organic-phase reaction was obtained. The effects of the reaction conditions on the conversion of DCDPM and the reaction rate were investigated in detail, including the agitation speed; the amounts of methanol, DCDPM, water, chlorobenzene, potassium hydroxide, and tetrabutylammonium bromide (TBAB); the ultrasonic power and frequency; the organic solvents; the quaternary ammonium salts; and the temperature. Rational explanations are provided for the experimental results.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8011616 Exemplaires
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Titre : FTIR study measuring the monomer reactivity ratios for ethylene−vinyl acetate polymerization in supercritical CO2 Type de document : texte imprimé Auteurs : William Z. Xu, Auteur ; Paul A. Charpentier, Auteur Année de publication : 2009 Article en page(s) : p. 1384–1390 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Supercritical CO2 Ethylene− Vinyl Polymerization Résumé :
An understanding of the monomer reactivity ratios is extremely useful for tailoring copolymers with desired compositions for a diversity of end-use applications. In situ ATR-FTIR was employed to monitor the initial formation of copolymers of ethylene and vinyl acetate (VAc) during polymerization in the “green” solvent supercritical carbon dioxide (scCO2). To obtain the copolymer composition, a calibration curve of the absorbance ratio 1737/2929 cm−1 versus vinyl acetate content of poly(ethylene-co-vinyl acetate) (PEVA) was established, covering the range of 5−98 wt %. The reactivity ratios for copolymerization of ethylene and VAc in scCO2 were determined using both the Kelen−Tudos and the nonlinear least-squares (NLLS) methods. Off-line 1H NMR analysis was also utilized for obtaining the copolymer composition, by which the determined reactivity ratios were compared with the ones obtained using in situ FTIR. The effect of reaction temperature and pressure on reactivity ratios was examined at 50 and 72 °C and at 13.8 and 27.6 MPa, with the lower temperature and higher pressure conditions increasing the reactivity ratios slightly. In situ FTIR was found to be able to accurately measure the reactivity ratios, and both the Kelen−Tudos and NNLS methods gave similar results. The obtained reactivity ratios will promote the application of the green solvent scCO2 in the production of the widely commercialized copolymer PEVA.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801275g
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1384–1390[article] FTIR study measuring the monomer reactivity ratios for ethylene−vinyl acetate polymerization in supercritical CO2 [texte imprimé] / William Z. Xu, Auteur ; Paul A. Charpentier, Auteur . - 2009 . - p. 1384–1390.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1384–1390
Mots-clés : Supercritical CO2 Ethylene− Vinyl Polymerization Résumé :
An understanding of the monomer reactivity ratios is extremely useful for tailoring copolymers with desired compositions for a diversity of end-use applications. In situ ATR-FTIR was employed to monitor the initial formation of copolymers of ethylene and vinyl acetate (VAc) during polymerization in the “green” solvent supercritical carbon dioxide (scCO2). To obtain the copolymer composition, a calibration curve of the absorbance ratio 1737/2929 cm−1 versus vinyl acetate content of poly(ethylene-co-vinyl acetate) (PEVA) was established, covering the range of 5−98 wt %. The reactivity ratios for copolymerization of ethylene and VAc in scCO2 were determined using both the Kelen−Tudos and the nonlinear least-squares (NLLS) methods. Off-line 1H NMR analysis was also utilized for obtaining the copolymer composition, by which the determined reactivity ratios were compared with the ones obtained using in situ FTIR. The effect of reaction temperature and pressure on reactivity ratios was examined at 50 and 72 °C and at 13.8 and 27.6 MPa, with the lower temperature and higher pressure conditions increasing the reactivity ratios slightly. In situ FTIR was found to be able to accurately measure the reactivity ratios, and both the Kelen−Tudos and NNLS methods gave similar results. The obtained reactivity ratios will promote the application of the green solvent scCO2 in the production of the widely commercialized copolymer PEVA.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801275g Exemplaires
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Titre : Gas phase chemistry in cellulose fast pyrolysis Type de document : texte imprimé Auteurs : R. Lanza, Auteur ; D. Dalle Nogare, Auteur ; P. Canu, Auteur Année de publication : 2009 Article en page(s) : p. 1391–1399 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Chemistry -- gas phase Cellulose pyrolysis Résumé :
We experimentally and theoretically studied cellulose pyrolysis at high temperature and short residence time. We investigated the gas phase chemistry with dedicated experiments and feeding intermediates. Results have been also compared with equilibrium calculations, both single (gas) phase and allowing for solid C formation. Our aim was to understand the cellulose degradation mechanism and particularly the role of gas phase chemistry. We provided evidence of a simplified mechanism, where CO formation is a first, fast step that can be related to levoglucosan ring opening, while H2 comes from a totally different route, based on hydrocarbon reforming reactions, which also provide further CO. In addition, butadiene was identified as a key intermediate in the decomposition sequence. The different paths and rates of CO formation and H2 formation explain why the ratio of CO to H2 is not constant, particularly at short residence time. A two-stage process or longer contact time is required, if aiming at syngas productionEn ligne : http://pubs.acs.org/doi/abs/10.1021/ie801280g
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1391–1399[article] Gas phase chemistry in cellulose fast pyrolysis [texte imprimé] / R. Lanza, Auteur ; D. Dalle Nogare, Auteur ; P. Canu, Auteur . - 2009 . - p. 1391–1399.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1391–1399
Mots-clés : Chemistry -- gas phase Cellulose pyrolysis Résumé :
We experimentally and theoretically studied cellulose pyrolysis at high temperature and short residence time. We investigated the gas phase chemistry with dedicated experiments and feeding intermediates. Results have been also compared with equilibrium calculations, both single (gas) phase and allowing for solid C formation. Our aim was to understand the cellulose degradation mechanism and particularly the role of gas phase chemistry. We provided evidence of a simplified mechanism, where CO formation is a first, fast step that can be related to levoglucosan ring opening, while H2 comes from a totally different route, based on hydrocarbon reforming reactions, which also provide further CO. In addition, butadiene was identified as a key intermediate in the decomposition sequence. The different paths and rates of CO formation and H2 formation explain why the ratio of CO to H2 is not constant, particularly at short residence time. A two-stage process or longer contact time is required, if aiming at syngas productionEn ligne : http://pubs.acs.org/doi/abs/10.1021/ie801280g Exemplaires
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Titre : Hydrogen production via reforming of the aqueous phase of bio-oil over Ni/Olivine catalysts in a spouted bed reactor Type de document : texte imprimé Auteurs : Panagiotis N. Kechagiopoulos, Auteur ; Spyros S. Voutetakis, Auteur Année de publication : 2009 Article en page(s) : p. 1400–1408 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hydrogen -- production Bio-Oil Ethylene glycol Acetic acid Résumé : Hydrogen produced from renewable energy sources can present significant environmental benefits as a means for clean power generation via fuel cells. The aqueous fraction of bio-oil can be used as a source for hydrogen production, if reformed in the presence of active catalytic materials. Recently, we introduced the concept of the spouted bed reactor for this particular process. The aim of the current work is to further investigate the suitability of the novel reactor. The effect of temperature, H2O/C ratio, space velocity, and heat treatment of support was investigated in the presence of Ni/Olivine catalysts. Runs were conducted with ethylene glycol and acetic acid as representative model compounds of the aqueous phase of bio-oil. The organics converted fully toward gases with high selectivity in hydrogen, while the known problem of coking was notably avoided. Ethylene glycol reforming seems to proceed primarily via decomposition followed by reforming of secondary products. Hydrogen yield during acetic acid reforming is higher under equivalent conditions. Tests using the aqueous phase of bio-oil proved more complicated due to the serious thermal instability of the feed. A new injection-cooling system was developed in order to achieve efficient feeding of bio-oil. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8013378
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1400–1408[article] Hydrogen production via reforming of the aqueous phase of bio-oil over Ni/Olivine catalysts in a spouted bed reactor [texte imprimé] / Panagiotis N. Kechagiopoulos, Auteur ; Spyros S. Voutetakis, Auteur . - 2009 . - p. 1400–1408.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1400–1408
Mots-clés : Hydrogen -- production Bio-Oil Ethylene glycol Acetic acid Résumé : Hydrogen produced from renewable energy sources can present significant environmental benefits as a means for clean power generation via fuel cells. The aqueous fraction of bio-oil can be used as a source for hydrogen production, if reformed in the presence of active catalytic materials. Recently, we introduced the concept of the spouted bed reactor for this particular process. The aim of the current work is to further investigate the suitability of the novel reactor. The effect of temperature, H2O/C ratio, space velocity, and heat treatment of support was investigated in the presence of Ni/Olivine catalysts. Runs were conducted with ethylene glycol and acetic acid as representative model compounds of the aqueous phase of bio-oil. The organics converted fully toward gases with high selectivity in hydrogen, while the known problem of coking was notably avoided. Ethylene glycol reforming seems to proceed primarily via decomposition followed by reforming of secondary products. Hydrogen yield during acetic acid reforming is higher under equivalent conditions. Tests using the aqueous phase of bio-oil proved more complicated due to the serious thermal instability of the feed. A new injection-cooling system was developed in order to achieve efficient feeding of bio-oil. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8013378 Exemplaires
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Titre : Present and future alkylation processes in refineries Type de document : texte imprimé Auteurs : Albright, Lyle F., Auteur Année de publication : 2009 Article en page(s) : p. 1409–1413 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Gasolines Refineries -- alkylation Résumé :
Isobutane has been alkylated with light (C3−C5) olefins for many years to produce high-quality, clean-burning gasolines. Processes that will significantly reduce operating costs and also produce higher-quality gasolines are proposed. These recommendations are based on recent improved understanding of process fundamentals, including the complicated chemical steps and the physical steps between and near the two or more phases in the reactor. Processes using sulfuric acid can be modified to reduce acid consumption significantly. Several solid catalysts have recently been proposed. All exhibit rapid catalyst deactivation for reasons explained in this article.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801495p
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1409–1413[article] Present and future alkylation processes in refineries [texte imprimé] / Albright, Lyle F., Auteur . - 2009 . - p. 1409–1413.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1409–1413
Mots-clés : Gasolines Refineries -- alkylation Résumé :
Isobutane has been alkylated with light (C3−C5) olefins for many years to produce high-quality, clean-burning gasolines. Processes that will significantly reduce operating costs and also produce higher-quality gasolines are proposed. These recommendations are based on recent improved understanding of process fundamentals, including the complicated chemical steps and the physical steps between and near the two or more phases in the reactor. Processes using sulfuric acid can be modified to reduce acid consumption significantly. Several solid catalysts have recently been proposed. All exhibit rapid catalyst deactivation for reasons explained in this article.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801495p Exemplaires
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Titre : Absorption of carbon dioxide into aqueous solutions of 2-piperidineethanol : kinetics analysis Type de document : texte imprimé Auteurs : Subham Paul, Auteur ; Aloke K. Ghoshal, Auteur ; Bishnupada Mandal, Auteur Année de publication : 2009 Article en page(s) : p. 1414–1419 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Carbon Dioxide -- Kinetics reaction Piperidineethanol analysis Résumé : This work presents the kinetics of the reaction of CO2 with aqueous 2-piperidineethanol (2-PE) solutions at 303, 313, and 323 K within the amine concentration range of 0.14−1.13 kmol m−3 using a wetted-wall column absorber. The reaction was described by zwitterionic mechanism to interpret the kinetic data. A qualitative 13C NMR analysis has been carried out for 2-PE solution in D2O after reaction with CO2, which has indicated the formation of bicarbonate ion. The reaction order was found to be in between 1.10 and 1.12 with respect to amine for the above-mentioned concentration range. The kinetic rate parameters were calculated and presented at each experimental condition. The second-order rate constants, k2, were obtained as 696, 1147, and 2047 m3 kmol−1 s−1 at 303, 313, and 323 K, respectively, with an activation energy of 45.2 kJ mol−1. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800723b
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1414–1419[article] Absorption of carbon dioxide into aqueous solutions of 2-piperidineethanol : kinetics analysis [texte imprimé] / Subham Paul, Auteur ; Aloke K. Ghoshal, Auteur ; Bishnupada Mandal, Auteur . - 2009 . - p. 1414–1419.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1414–1419
Mots-clés : Carbon Dioxide -- Kinetics reaction Piperidineethanol analysis Résumé : This work presents the kinetics of the reaction of CO2 with aqueous 2-piperidineethanol (2-PE) solutions at 303, 313, and 323 K within the amine concentration range of 0.14−1.13 kmol m−3 using a wetted-wall column absorber. The reaction was described by zwitterionic mechanism to interpret the kinetic data. A qualitative 13C NMR analysis has been carried out for 2-PE solution in D2O after reaction with CO2, which has indicated the formation of bicarbonate ion. The reaction order was found to be in between 1.10 and 1.12 with respect to amine for the above-mentioned concentration range. The kinetic rate parameters were calculated and presented at each experimental condition. The second-order rate constants, k2, were obtained as 696, 1147, and 2047 m3 kmol−1 s−1 at 303, 313, and 323 K, respectively, with an activation energy of 45.2 kJ mol−1. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800723b Exemplaires
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Titre : A new method for evaluation of the isothermal conversion curves from the nonisothermal measurements. application in nickel axide reduction kinetics Type de document : texte imprimé Auteurs : Borivoj Adnadjevic, Auteur ; Bojan Jankovic, Auteur Année de publication : 2009 Article en page(s) : p. 1420–1427 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Metal oxide Nickel -- reduction kinetics Résumé :
A new method for evaluation of isothermal conversion curves from the experimentally determined nonisothermal conversion curves for the nickel oxide reduction process in hydrogen atmosphere was established. It was concluded that by applying the conventional and proposed prediction methods it was not possible (at Tiso ≤ 300 °C) to calculate the isothermal conversion curves using the experimentally obtained nonisothermal conversion curves for this reduction process. The dependence of the apparent activation energy on the degree of conversion shows that the investigated reduction process is complex under isothermal or nonisothermal conditions. By applying Miura’s procedure, the shape of density distribution functions of the apparent activation energies was determined for the isothermal and nonisothermal reduction processes. It was concluded that the existence of different distributions of internal energy of the NiO reduction centers is a consequence of different reduction kinetics under isothermal and nonisothermal experimental conditions.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801074j
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1420–1427[article] A new method for evaluation of the isothermal conversion curves from the nonisothermal measurements. application in nickel axide reduction kinetics [texte imprimé] / Borivoj Adnadjevic, Auteur ; Bojan Jankovic, Auteur . - 2009 . - p. 1420–1427.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1420–1427
Mots-clés : Metal oxide Nickel -- reduction kinetics Résumé :
A new method for evaluation of isothermal conversion curves from the experimentally determined nonisothermal conversion curves for the nickel oxide reduction process in hydrogen atmosphere was established. It was concluded that by applying the conventional and proposed prediction methods it was not possible (at Tiso ≤ 300 °C) to calculate the isothermal conversion curves using the experimentally obtained nonisothermal conversion curves for this reduction process. The dependence of the apparent activation energy on the degree of conversion shows that the investigated reduction process is complex under isothermal or nonisothermal conditions. By applying Miura’s procedure, the shape of density distribution functions of the apparent activation energies was determined for the isothermal and nonisothermal reduction processes. It was concluded that the existence of different distributions of internal energy of the NiO reduction centers is a consequence of different reduction kinetics under isothermal and nonisothermal experimental conditions.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801074j Exemplaires
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Titre : Increasing productivity of microreactors for fast gas-liquid reactions : the case of direct fluorination of toluene Type de document : texte imprimé Auteurs : Nuria De Mas, Auteur ; Axel Günther, Auteur ; Martin A. Schmidt, Auteur Année de publication : 2009 Article en page(s) : p. 1428–1434 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Microreactors -- Productivity Gas-liquid Superficial gas Résumé :
The throughput of a single-channel microreactor used for a fast gas-liquid reaction was increased by up to one order of magnitude relative to previously published results by simultaneously increasing the superficial gas and liquid velocities. Superficial gas and liquid velocities varied between 2.9-14.6 m/s and 0.012–0.061 m/s, respectively. The direct fluorination of toluene in acetonitrile, selected as a model reaction, was performed at room temperature in microchannels formed in a silicon substrate, coated with thermally grown silicon oxide and evaporated nickel, and capped by Pyrex. With faster velocities the toluene conversion increased from 63% to 76%, while the combined selectivity of ortho-, meta-, and para-fluorotoluene isomers remained constant at 26%. Operating at faster gas and liquid velocities appeared to enhance the contacting between the two phases, thus outweighing the reduced liquid residence time.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801232d
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1428–1434[article] Increasing productivity of microreactors for fast gas-liquid reactions : the case of direct fluorination of toluene [texte imprimé] / Nuria De Mas, Auteur ; Axel Günther, Auteur ; Martin A. Schmidt, Auteur . - 2009 . - p. 1428–1434.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1428–1434
Mots-clés : Microreactors -- Productivity Gas-liquid Superficial gas Résumé :
The throughput of a single-channel microreactor used for a fast gas-liquid reaction was increased by up to one order of magnitude relative to previously published results by simultaneously increasing the superficial gas and liquid velocities. Superficial gas and liquid velocities varied between 2.9-14.6 m/s and 0.012–0.061 m/s, respectively. The direct fluorination of toluene in acetonitrile, selected as a model reaction, was performed at room temperature in microchannels formed in a silicon substrate, coated with thermally grown silicon oxide and evaporated nickel, and capped by Pyrex. With faster velocities the toluene conversion increased from 63% to 76%, while the combined selectivity of ortho-, meta-, and para-fluorotoluene isomers remained constant at 26%. Operating at faster gas and liquid velocities appeared to enhance the contacting between the two phases, thus outweighing the reduced liquid residence time.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801232d Exemplaires
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Titre : Catalytic gasification of glucose over Ni/activated charcoal in supercritical water Type de document : texte imprimé Auteurs : In-Gu Lee, Auteur ; Son-Ki Ihm, Auteur Année de publication : 2009 Article en page(s) : p. 1435–1442 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Glucose -- Catalytic gasification Ni/Activated Charcoal Résumé :
Gasification of glucose was carried out over the 16 wt % Ni/activated charcoal in supercritical water at 28 MPa. Effects of temperature (575−725 °C), feed concentration (0.3−0.9 M), and LHSV (6−24 h−1) were investigated on the product distribution. For comparison, the gasification experiments were performed with activated charcoal and also without catalyst. While the Ni/activated charcoal catalyst showed a good yield of hydrogen, it was deactivated due to coke deposition especially at low temperatures below 650 °C and also due to sintering of nickel particles.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8012456
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1435–1442[article] Catalytic gasification of glucose over Ni/activated charcoal in supercritical water [texte imprimé] / In-Gu Lee, Auteur ; Son-Ki Ihm, Auteur . - 2009 . - p. 1435–1442.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1435–1442
Mots-clés : Glucose -- Catalytic gasification Ni/Activated Charcoal Résumé :
Gasification of glucose was carried out over the 16 wt % Ni/activated charcoal in supercritical water at 28 MPa. Effects of temperature (575−725 °C), feed concentration (0.3−0.9 M), and LHSV (6−24 h−1) were investigated on the product distribution. For comparison, the gasification experiments were performed with activated charcoal and also without catalyst. While the Ni/activated charcoal catalyst showed a good yield of hydrogen, it was deactivated due to coke deposition especially at low temperatures below 650 °C and also due to sintering of nickel particles.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8012456 Exemplaires
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Titre : Estimation of wetting efficiency in trickle-bed reactors for nonlinear kinetics Type de document : texte imprimé Auteurs : Mogalicherla, Aswani Kumar, Auteur ; Gaurav Sharma, Auteur ; Deepak Kunzru, Auteur Année de publication : 2009 Article en page(s) : p. 1443–1450 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Trickle-bed reactors Intrinsic kinetic Résumé :
A procedure has been developed for estimating the wetting efficiency in a trickle-bed reactor by using the conversion data obtained for a reaction following nonlinear kinetics. For this purpose, the hydrogenation of α-methylstyrene on 0.5 wt % Pd/Al2O3 catalyst was studied in a batch slurry reactor (1.0−6.0 atm, 313−343 K), as well as in a trickle-bed reactor (313 K, 1.0−2.5 atm). The superficial velocities of gas and liquid in the trickle-bed reactor (TBR) were in the range of 0.25−1.0 cm/s and 0.06−0.24 cm/s, respectively. The intrinsic power-law kinetics, determined from the data obtained in the batch reactor, was used to calculate the effectiveness factors in the TBR. A comparison of these effectiveness factors with those calculated assuming complete external wetting showed that the wetting was not complete. The external wetting efficiencies (f) were determined using the method proposed by Ramachandran and Smith [ AIChE J.1979, 25 (3), 538.]. To this end, effectiveness factors for the catalyst completely covered with gas or liquid were estimated for this nonlinear kinetics by a previously published procedure. f varied between 40% and 75% with the liquid superficial velocity. The difference between f values calculated from the conversion data and from the correlation developed using residence time distribution (RTD) data was attributed to the presence of stagnant liquid zones between the catalyst particles.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801305t
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1443–1450[article] Estimation of wetting efficiency in trickle-bed reactors for nonlinear kinetics [texte imprimé] / Mogalicherla, Aswani Kumar, Auteur ; Gaurav Sharma, Auteur ; Deepak Kunzru, Auteur . - 2009 . - p. 1443–1450.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1443–1450
Mots-clés : Trickle-bed reactors Intrinsic kinetic Résumé :
A procedure has been developed for estimating the wetting efficiency in a trickle-bed reactor by using the conversion data obtained for a reaction following nonlinear kinetics. For this purpose, the hydrogenation of α-methylstyrene on 0.5 wt % Pd/Al2O3 catalyst was studied in a batch slurry reactor (1.0−6.0 atm, 313−343 K), as well as in a trickle-bed reactor (313 K, 1.0−2.5 atm). The superficial velocities of gas and liquid in the trickle-bed reactor (TBR) were in the range of 0.25−1.0 cm/s and 0.06−0.24 cm/s, respectively. The intrinsic power-law kinetics, determined from the data obtained in the batch reactor, was used to calculate the effectiveness factors in the TBR. A comparison of these effectiveness factors with those calculated assuming complete external wetting showed that the wetting was not complete. The external wetting efficiencies (f) were determined using the method proposed by Ramachandran and Smith [ AIChE J.1979, 25 (3), 538.]. To this end, effectiveness factors for the catalyst completely covered with gas or liquid were estimated for this nonlinear kinetics by a previously published procedure. f varied between 40% and 75% with the liquid superficial velocity. The difference between f values calculated from the conversion data and from the correlation developed using residence time distribution (RTD) data was attributed to the presence of stagnant liquid zones between the catalyst particles.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801305t Exemplaires
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Titre : Catalytic decomposition of SO3 over Pt/BaSO4 materials in sulfur-iodine cycle for hydrogen production Type de document : texte imprimé Auteurs : Bhari Mallanna Nagaraja, Auteur ; Kwang Deog Jung, Auteur ; Byoung Sung Ahn, Auteur Année de publication : 2009 Article en page(s) : p. 1451–1457 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hydrogen -- Production sulfur Iodine Pt/BaSO4 SO3 Résumé :
Various platinum-supported barium sulfate catalysts have been employed for SO3 decomposition in sulfur−iodine cycle to produce hydrogen. Before impregnation of platinum, barium sulfate as a support has been prepared by different methods, i.e., using ethylene glycol (EG) and water by dispersion method and EG and propanol by spray pyrolysis. The influence of the supports on catalytic performance was examined with three catalysts: 1.0Pt/BaSO4 (PrOH), 1.0Pt/BaSO4 (EG), and 1.0Pt/BaSO4 (H2O) at various temperatures for SO3 decomposition. 1.0Pt/BaSO4 (PrOH) prepared by spray pyrolysis showed high SO3 conversion (62%) at low temperature (1023 K) compared with the other catalysts prepared by dispersion method. The effect of Pt loading on catalytic activity has been performed with BaSO4 impregnated by various amounts of platinum. Under identical conditions, the 1.0Pt/BaSO4 catalyst showed the highest catalytic performance because of high surface area and small particle size of platinum.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801328w
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1451–1457[article] Catalytic decomposition of SO3 over Pt/BaSO4 materials in sulfur-iodine cycle for hydrogen production [texte imprimé] / Bhari Mallanna Nagaraja, Auteur ; Kwang Deog Jung, Auteur ; Byoung Sung Ahn, Auteur . - 2009 . - p. 1451–1457.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1451–1457
Mots-clés : Hydrogen -- Production sulfur Iodine Pt/BaSO4 SO3 Résumé :
Various platinum-supported barium sulfate catalysts have been employed for SO3 decomposition in sulfur−iodine cycle to produce hydrogen. Before impregnation of platinum, barium sulfate as a support has been prepared by different methods, i.e., using ethylene glycol (EG) and water by dispersion method and EG and propanol by spray pyrolysis. The influence of the supports on catalytic performance was examined with three catalysts: 1.0Pt/BaSO4 (PrOH), 1.0Pt/BaSO4 (EG), and 1.0Pt/BaSO4 (H2O) at various temperatures for SO3 decomposition. 1.0Pt/BaSO4 (PrOH) prepared by spray pyrolysis showed high SO3 conversion (62%) at low temperature (1023 K) compared with the other catalysts prepared by dispersion method. The effect of Pt loading on catalytic activity has been performed with BaSO4 impregnated by various amounts of platinum. Under identical conditions, the 1.0Pt/BaSO4 catalyst showed the highest catalytic performance because of high surface area and small particle size of platinum.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801328w Exemplaires
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Titre : Fe(III)-immobilized collagen fiber : a renewable heterogeneous catalyst for the photoassisted decomposition of orange II Type de document : texte imprimé Auteurs : Xiaohu Liu, Auteur ; Rui Tang, Auteur ; Qiang He, Auteur Année de publication : 2009 Article en page(s) : p. 1458–1463 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Fe(III) Collagen fiber Heterogeneous catalyst Résumé :
A novel catalyst for the Fenton reaction was prepared by immobilizing Fe(III) onto collagen fiber, and its catalytic activity for the photoassisted decomposition of Orange II was investigated. The results indicated that this catalyst, Fe(III)-immobilized collagen fiber (FICF), follows an adsorption-decomposition mechanism so that it can effectively accelerate the decoloration and mineralization rates of Orange II in aqueous solution. Catalyzed by FICF (0.5 g/L, 91 mg/g Fe loading), the TOC of Orange II solution (1000 mL, 0.2 mM, pH 6.42) was 62.9% removed within 90 min under UVC irradiation (254 nm, 10 W) in the presence of H2O2 (5.0 mM); meanwhile, the dye solution was completely decolorized. FICF can be recycled 10 times with little activity loss, and its catalytic activity can be easily recovered by reimmobilization of Fe(III). Therefore, FICF could act as an efficient and cost-effective catalyst for the photoassisted decomposition of Orange II.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801330m
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1458–1463[article] Fe(III)-immobilized collagen fiber : a renewable heterogeneous catalyst for the photoassisted decomposition of orange II [texte imprimé] / Xiaohu Liu, Auteur ; Rui Tang, Auteur ; Qiang He, Auteur . - 2009 . - p. 1458–1463.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1458–1463
Mots-clés : Fe(III) Collagen fiber Heterogeneous catalyst Résumé :
A novel catalyst for the Fenton reaction was prepared by immobilizing Fe(III) onto collagen fiber, and its catalytic activity for the photoassisted decomposition of Orange II was investigated. The results indicated that this catalyst, Fe(III)-immobilized collagen fiber (FICF), follows an adsorption-decomposition mechanism so that it can effectively accelerate the decoloration and mineralization rates of Orange II in aqueous solution. Catalyzed by FICF (0.5 g/L, 91 mg/g Fe loading), the TOC of Orange II solution (1000 mL, 0.2 mM, pH 6.42) was 62.9% removed within 90 min under UVC irradiation (254 nm, 10 W) in the presence of H2O2 (5.0 mM); meanwhile, the dye solution was completely decolorized. FICF can be recycled 10 times with little activity loss, and its catalytic activity can be easily recovered by reimmobilization of Fe(III). Therefore, FICF could act as an efficient and cost-effective catalyst for the photoassisted decomposition of Orange II.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801330m Exemplaires
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Titre : Determination of distributed activation energy model kinetic parameters using simulated annealing optimization method for nonisothermal pyrolysis of lignin Type de document : texte imprimé Auteurs : Thilakavathi Mani, Auteur ; Pulikesi Murugan, Auteur ; Nader Mahinpey, Auteur Année de publication : 2009 Article en page(s) : p. 1464–1467 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Energy model -- distribution kinetic Résumé :
The distributed activation energy model (DAEM) has been shown to be more descriptive of the pyrolysis reaction than other applicable models. In this study, the temperature dependency of the preexponential factor has been included in the DAEM. The model equation has been solved using Simpson’s 1/3 rule, and the kinetic parameters were determined using an optimization method. Simulated annealing method has been used to determine the DAEM kinetic parameters for the nonisothermal pyrolysis of lignin using thermogravimetric analysis (TGA) data. The nonisothermal pyrolysis of lignin was conducted at three different heating rates of 5, 10, and 15 °C/min under nitrogen atmosphere. Predicted results from the optimum kinetic parameters have been compared with the experimental data. The DAEM equation predicts the experimental data very well for different heating rates.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8013605
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1464–1467[article] Determination of distributed activation energy model kinetic parameters using simulated annealing optimization method for nonisothermal pyrolysis of lignin [texte imprimé] / Thilakavathi Mani, Auteur ; Pulikesi Murugan, Auteur ; Nader Mahinpey, Auteur . - 2009 . - p. 1464–1467.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1464–1467
Mots-clés : Energy model -- distribution kinetic Résumé :
The distributed activation energy model (DAEM) has been shown to be more descriptive of the pyrolysis reaction than other applicable models. In this study, the temperature dependency of the preexponential factor has been included in the DAEM. The model equation has been solved using Simpson’s 1/3 rule, and the kinetic parameters were determined using an optimization method. Simulated annealing method has been used to determine the DAEM kinetic parameters for the nonisothermal pyrolysis of lignin using thermogravimetric analysis (TGA) data. The nonisothermal pyrolysis of lignin was conducted at three different heating rates of 5, 10, and 15 °C/min under nitrogen atmosphere. Predicted results from the optimum kinetic parameters have been compared with the experimental data. The DAEM equation predicts the experimental data very well for different heating rates.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8013605 Exemplaires
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Titre : Novel synthesis and characterization of yellow inorganic/organic composite spheres for electrophoretic display Type de document : texte imprimé Auteurs : Jihai Duan, Auteur ; Yaqing Feng, Auteur ; Guang Yang, Auteur Année de publication : 2009 Article en page(s) : p. 1468–1475 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Cds Electronic paper Résumé :
Yellow CdS/wax nanocomposite spheres were fabricated in an aqueous solution by an emulsion method, in which the CdS nanoparticles were adsorbed on the surface of a wax core with positive charge by electrostatic self-assembly. A thin shell of SiO2 was then coated to the yellow CdS/wax spheres by the hydrolysis of Na2SiO3 in the same aqueous solution to enhance the optical and mechanical properties and the charge load of the composite spheres. The product was characterized by transmission electron microscopy, scanning electron microscope, atomic force microscopy, thermogravimetric analysis, and X-ray powder diffraction, which showed that the SiO2 walls of spheres were compact and part of CdS crystals dispersed inside, the density of composite spheres being about 1.3 g/cm3, which match most of the suspensions. Fourier transform infrared spectroscopy, and energy dispersive X-ray spectrometry showed the component of composite spheres. Dynamic light scattering showed the diameter distribution of composite spheres was between 100∼400 nm. Zeta-potential measurement proved that the SiO2/CdS/wax spheres had a higher charge load, and Ultraviolet−visible spectra showed that the SiO2/CdS/wax spheres had a better optical property. Therefore, this type of composite spheres had the merits of low density and strong durability in environments. The response behavior of the microencapsulated electronic ink of the composite spheres has been measured. This novel method is expected to produce various inorganic/organic nanocomposite spheres with potential application in the fields of electronic paper and other material science.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800416w
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1468–1475[article] Novel synthesis and characterization of yellow inorganic/organic composite spheres for electrophoretic display [texte imprimé] / Jihai Duan, Auteur ; Yaqing Feng, Auteur ; Guang Yang, Auteur . - 2009 . - p. 1468–1475.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1468–1475
Mots-clés : Cds Electronic paper Résumé :
Yellow CdS/wax nanocomposite spheres were fabricated in an aqueous solution by an emulsion method, in which the CdS nanoparticles were adsorbed on the surface of a wax core with positive charge by electrostatic self-assembly. A thin shell of SiO2 was then coated to the yellow CdS/wax spheres by the hydrolysis of Na2SiO3 in the same aqueous solution to enhance the optical and mechanical properties and the charge load of the composite spheres. The product was characterized by transmission electron microscopy, scanning electron microscope, atomic force microscopy, thermogravimetric analysis, and X-ray powder diffraction, which showed that the SiO2 walls of spheres were compact and part of CdS crystals dispersed inside, the density of composite spheres being about 1.3 g/cm3, which match most of the suspensions. Fourier transform infrared spectroscopy, and energy dispersive X-ray spectrometry showed the component of composite spheres. Dynamic light scattering showed the diameter distribution of composite spheres was between 100∼400 nm. Zeta-potential measurement proved that the SiO2/CdS/wax spheres had a higher charge load, and Ultraviolet−visible spectra showed that the SiO2/CdS/wax spheres had a better optical property. Therefore, this type of composite spheres had the merits of low density and strong durability in environments. The response behavior of the microencapsulated electronic ink of the composite spheres has been measured. This novel method is expected to produce various inorganic/organic nanocomposite spheres with potential application in the fields of electronic paper and other material science.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800416w Exemplaires
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Titre : Interfacial tension and density of water + branched hydrocarbon bnary systems in the range 303-343 K Type de document : texte imprimé Auteurs : Carlos Gilberto Aranda-Bravo, Auteur ; Ascención Romero-Martínez, Auteur ; Arturo Trejo, Auteur Année de publication : 2009 Article en page(s) : p. 1476–1483 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Interfacial Tension Thermophysical Water -- Density Hydrocarbon Résumé :
Experimental results for the liquid-liquid interfacial tension of water + branched hydrocarbon binary systems were obtained using the pendant drop method. The branched hydrocarbons included in this study were 2-methylpentane and 3-methylpentane as structural isomers of C6H14; 2,3-dimethylpentane as isomer of C7H16; and 2,2,4-trimethylpentane and 2,3,4-trimethylpentane as isomers of C8H18. The temperatures at which the experiments were carried out were 303.15, 313.15, 323.15, 333.15, and 343.15 K. Density values of both saturated liquid phases were also experimentally determined. An experimental apparatus for achieving the liquid−liquid equilibrium with online sampling and density measurement was developed. Density values obtained for both saturated liquid phases follow the expected behavior with temperature: they decrease with increasing temperature, whereas the effect of the structural isomerism on density was mainly observed on the results for the hydrocarbon-rich liquid phase. Also, the interfacial tension values decrease with increasing temperature for a given water + hydrocarbon binary system and as the size of the hydrocarbon increases. Estimated values for the interfacial tension of the systems with the different branched isomers were obtained using a method developed in previous work.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801101r
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1476–1483[article] Interfacial tension and density of water + branched hydrocarbon bnary systems in the range 303-343 K [texte imprimé] / Carlos Gilberto Aranda-Bravo, Auteur ; Ascención Romero-Martínez, Auteur ; Arturo Trejo, Auteur . - 2009 . - p. 1476–1483.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1476–1483
Mots-clés : Interfacial Tension Thermophysical Water -- Density Hydrocarbon Résumé :
Experimental results for the liquid-liquid interfacial tension of water + branched hydrocarbon binary systems were obtained using the pendant drop method. The branched hydrocarbons included in this study were 2-methylpentane and 3-methylpentane as structural isomers of C6H14; 2,3-dimethylpentane as isomer of C7H16; and 2,2,4-trimethylpentane and 2,3,4-trimethylpentane as isomers of C8H18. The temperatures at which the experiments were carried out were 303.15, 313.15, 323.15, 333.15, and 343.15 K. Density values of both saturated liquid phases were also experimentally determined. An experimental apparatus for achieving the liquid−liquid equilibrium with online sampling and density measurement was developed. Density values obtained for both saturated liquid phases follow the expected behavior with temperature: they decrease with increasing temperature, whereas the effect of the structural isomerism on density was mainly observed on the results for the hydrocarbon-rich liquid phase. Also, the interfacial tension values decrease with increasing temperature for a given water + hydrocarbon binary system and as the size of the hydrocarbon increases. Estimated values for the interfacial tension of the systems with the different branched isomers were obtained using a method developed in previous work.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801101r Exemplaires
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Titre : Measurement of autogenous pressure and dissociated species during the thermolysis of mesitylene for the synthesis of monodispersed, pure, paramagnetic carbon particles Type de document : texte imprimé Auteurs : Pol, Vilas G., Auteur ; P. Thiyagarajan, Auteur Année de publication : 2009 Article en page(s) : p. 1484–1489 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : spherical carbon particles Autogenous pressure Mesitylene Résumé :
Two reaction parameters are important for the synthesis of entirely monodispersed, pure, paramagnetic spherical carbon particles. The experimental setup is developed to measure in situ autogenous pressure as a function of temperature during the thermolysis of mesitylene in a closed reactor. In situ mass spectrometry analyzed the dissociated species during the heating cycle of mesitylene as a function of temperature. The morphology, structure, composition, and magnetic properties of the as-prepared spherical carbon particles are characterized by using SEM, XRD, Raman spectroscopy, EDX, CHNS analysis, and EPR.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8014928
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1484–1489[article] Measurement of autogenous pressure and dissociated species during the thermolysis of mesitylene for the synthesis of monodispersed, pure, paramagnetic carbon particles [texte imprimé] / Pol, Vilas G., Auteur ; P. Thiyagarajan, Auteur . - 2009 . - p. 1484–1489.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1484–1489
Mots-clés : spherical carbon particles Autogenous pressure Mesitylene Résumé :
Two reaction parameters are important for the synthesis of entirely monodispersed, pure, paramagnetic spherical carbon particles. The experimental setup is developed to measure in situ autogenous pressure as a function of temperature during the thermolysis of mesitylene in a closed reactor. In situ mass spectrometry analyzed the dissociated species during the heating cycle of mesitylene as a function of temperature. The morphology, structure, composition, and magnetic properties of the as-prepared spherical carbon particles are characterized by using SEM, XRD, Raman spectroscopy, EDX, CHNS analysis, and EPR.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8014928 Exemplaires
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Titre : Effects of processing parameters on the morphology of precipitated manganese oxide powders Type de document : texte imprimé Auteurs : Qiang Zhao, Auteur ; Shih, Wan Y., Auteur ; Shih, Wei-Heng, Auteur Année de publication : 2009 Article en page(s) : p. 1490–1494 Langues : Anglais (eng) Mots-clés : Manganese oxide powders Résumé :
It is desirable that the surface area of catalytic materials can be controlled by adjusting the processing parameters. In this paper we report that the morphology of precipitated manganese oxide powders after 500 °C calcination is affected by the volume ratio between the manganese nitrate precursor and ammonium hydroxide and also by the concentration of the precursor solution. When a large amount of ammonium hydroxide (nominal concentration of NH4OH in the final suspension greater than 4 N) was used, the synthesized powder had plate-like particles with higher specific surface area compared to spherical particles made by a small amount of ammonium hydroxide (nominal concentration of NH4OH less than 1 N). Thinner plates were synthesized from the system with lower nominal concentration of Mn(NO3)2, resulting in even higher specific surface area. The surface area differences between these powders synthesized by different conditions decreased as the calcination temperatures increased from 500 to 900 °C because the high calcination temperatures eliminated the morphology difference among them.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801173e
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1490–1494[article] Effects of processing parameters on the morphology of precipitated manganese oxide powders [texte imprimé] / Qiang Zhao, Auteur ; Shih, Wan Y., Auteur ; Shih, Wei-Heng, Auteur . - 2009 . - p. 1490–1494.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1490–1494
Mots-clés : Manganese oxide powders Résumé :
It is desirable that the surface area of catalytic materials can be controlled by adjusting the processing parameters. In this paper we report that the morphology of precipitated manganese oxide powders after 500 °C calcination is affected by the volume ratio between the manganese nitrate precursor and ammonium hydroxide and also by the concentration of the precursor solution. When a large amount of ammonium hydroxide (nominal concentration of NH4OH in the final suspension greater than 4 N) was used, the synthesized powder had plate-like particles with higher specific surface area compared to spherical particles made by a small amount of ammonium hydroxide (nominal concentration of NH4OH less than 1 N). Thinner plates were synthesized from the system with lower nominal concentration of Mn(NO3)2, resulting in even higher specific surface area. The surface area differences between these powders synthesized by different conditions decreased as the calcination temperatures increased from 500 to 900 °C because the high calcination temperatures eliminated the morphology difference among them.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801173e Exemplaires
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Titre : Iterative identification of continuous-time hammerstein and wiener systems using a two-stage estimation algorithm Type de document : texte imprimé Auteurs : Ho-Tsen Chen, Auteur ; Shyh-Hong Hwang, Auteur ; Chuei-Tin Chang, Auteur Année de publication : 2009 Article en page(s) : p. 1495–1510 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Nonlinear processes Hammerstein Systems Wiener Résumé :
This article presents an iterative method to deal with the identification of continuous-time single-input/single-output Hammerstein and Wiener systems, characterized by a series connection of a nonlinear static element and a linear dynamic element. The internal variable between the nonlinear and linear elements is inaccessible to measurements so that simultaneous parameter estimation of the two elements cannot be easily achieved in a least-squares fashion. This difficulty could be circumvented by updating the internal variable at each iteration step. A two-stage estimation algorithm, in conjunction with moving-horizon smoothing and a solution-guiding mechanism, is established to ensure the convergence and accuracy of the iterative method in the face of linear structure mismatch, high static nonlinearity with an unknown characteristic, and severe noise. At the first stage, a good description of the static nonlinearity is given by a multisegment function or a polynomial in an iterative manner. Linear structure mismatch is allowed for this stage of estimation. At the second stage, the identification problem is reduced to a simple linear one with the internal variable gained at the first stage. A noniterative procedure can then be applied to determine accurately the structure and parameters of the linear dynamic element. Studies with simulated and experimental examples demonstrate that the proposed identification method is valid for a wide variety of nonlinear system dynamics and test conditions.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800149w
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1495–1510[article] Iterative identification of continuous-time hammerstein and wiener systems using a two-stage estimation algorithm [texte imprimé] / Ho-Tsen Chen, Auteur ; Shyh-Hong Hwang, Auteur ; Chuei-Tin Chang, Auteur . - 2009 . - p. 1495–1510.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1495–1510
Mots-clés : Nonlinear processes Hammerstein Systems Wiener Résumé :
This article presents an iterative method to deal with the identification of continuous-time single-input/single-output Hammerstein and Wiener systems, characterized by a series connection of a nonlinear static element and a linear dynamic element. The internal variable between the nonlinear and linear elements is inaccessible to measurements so that simultaneous parameter estimation of the two elements cannot be easily achieved in a least-squares fashion. This difficulty could be circumvented by updating the internal variable at each iteration step. A two-stage estimation algorithm, in conjunction with moving-horizon smoothing and a solution-guiding mechanism, is established to ensure the convergence and accuracy of the iterative method in the face of linear structure mismatch, high static nonlinearity with an unknown characteristic, and severe noise. At the first stage, a good description of the static nonlinearity is given by a multisegment function or a polynomial in an iterative manner. Linear structure mismatch is allowed for this stage of estimation. At the second stage, the identification problem is reduced to a simple linear one with the internal variable gained at the first stage. A noniterative procedure can then be applied to determine accurately the structure and parameters of the linear dynamic element. Studies with simulated and experimental examples demonstrate that the proposed identification method is valid for a wide variety of nonlinear system dynamics and test conditions.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800149w Exemplaires
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Titre : Selecting the optimal target company based on synergy calculation for the vertical merger in a petrochemical complex Type de document : texte imprimé Auteurs : Sung-Geun Yoon, Auteur ; Sunwon Park, Auteur ; Jeongseok Lee, Auteur Année de publication : 2009 Article en page(s) : p. 1511–1521 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Petrochemical -- mergers acquisitions Résumé :
Petrochemical companies have focused on mergers and acquisitions (M&A) as a strategic option; however, there are very few quantitative tools which can critically evaluate M&A. The objectives of M&A are rapid growth by increasing the external scale of a company and strengthening its cost competitiveness. In particular, many petrochemical mergers occur within a complex. This study presents a novel mathematical model to select an optimal target company for the vertical merger in a petrochemical complex. The model is applied to the problem of one acquirer and five target companies within a complex. The results of the optimization studies are analyzed with regard to profit, synergy, variability, and cost efficiency of the merger. One target company is ultimately selected with a synergy of $264 million with $0.81 million of capital investment. The industrial case study demonstrates the viability of the given model for analyzing real M&A problems within a complex.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8011787
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1511–1521[article] Selecting the optimal target company based on synergy calculation for the vertical merger in a petrochemical complex [texte imprimé] / Sung-Geun Yoon, Auteur ; Sunwon Park, Auteur ; Jeongseok Lee, Auteur . - 2009 . - p. 1511–1521.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1511–1521
Mots-clés : Petrochemical -- mergers acquisitions Résumé :
Petrochemical companies have focused on mergers and acquisitions (M&A) as a strategic option; however, there are very few quantitative tools which can critically evaluate M&A. The objectives of M&A are rapid growth by increasing the external scale of a company and strengthening its cost competitiveness. In particular, many petrochemical mergers occur within a complex. This study presents a novel mathematical model to select an optimal target company for the vertical merger in a petrochemical complex. The model is applied to the problem of one acquirer and five target companies within a complex. The results of the optimization studies are analyzed with regard to profit, synergy, variability, and cost efficiency of the merger. One target company is ultimately selected with a synergy of $264 million with $0.81 million of capital investment. The industrial case study demonstrates the viability of the given model for analyzing real M&A problems within a complex.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8011787 Exemplaires
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Titre : Online sensor/actuator failure isolation and reconfigurablecontrol using the generalized likelihood ratio method Type de document : texte imprimé Auteurs : Anjali P. Deshpande, Auteur ; Ujjwal Zamad, Auteur ; Sachin C. Patwardhan, Auteur Année de publication : 2009 Article en page(s) : p. 1522–1535 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Sensor -- Control Actuator failure Diagnose online Résumé : In processing plants, sensor and/or actuator failures can have considerable deteriorating effect on the closed-loop performance. Such failures have to be diagnosed online, as quickly as possible, and actively accommodated to arrest the performance degradation. Active failure tolerance can be achieved by employing model-based failure diagnosis techniques and redesigning/restructuring controller online. In this work, a sensor/actuator failure isolation strategy has been developed under the linear generalized likelihood ratio (GLR) framework. The strategy is then extended to isolation of sensor and actuator failures in nonlinear systems. The infomation on sensor/actuator failures is further used for online reconfiguration of the state estimator and the controller/control scheme. In case of sensor failure, the state estimator is reconfigured by removing the measurement of failed sensor from the measurement vector. If an observability property is preserved after sensor failure, then an inferential control scheme is employed subsequent to the failure. When an actuator failure is isolated, it is proposed to make modifications in the controller objectives or switch to a new controller to account for the loss of a degree of freedom. The efficacy of the proposed failure diagnosis and control structure reconfiguration schemes is demonstrated by conducting experimental studies on a benchmark heater mixer set up. Analysis of these results reveals that the proposed strategies are able to isolate the failures accurately and recover the closed-loop performance by online reconfiguration of the controller/control scheme. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8003122
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1522–1535[article] Online sensor/actuator failure isolation and reconfigurablecontrol using the generalized likelihood ratio method [texte imprimé] / Anjali P. Deshpande, Auteur ; Ujjwal Zamad, Auteur ; Sachin C. Patwardhan, Auteur . - 2009 . - p. 1522–1535.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1522–1535
Mots-clés : Sensor -- Control Actuator failure Diagnose online Résumé : In processing plants, sensor and/or actuator failures can have considerable deteriorating effect on the closed-loop performance. Such failures have to be diagnosed online, as quickly as possible, and actively accommodated to arrest the performance degradation. Active failure tolerance can be achieved by employing model-based failure diagnosis techniques and redesigning/restructuring controller online. In this work, a sensor/actuator failure isolation strategy has been developed under the linear generalized likelihood ratio (GLR) framework. The strategy is then extended to isolation of sensor and actuator failures in nonlinear systems. The infomation on sensor/actuator failures is further used for online reconfiguration of the state estimator and the controller/control scheme. In case of sensor failure, the state estimator is reconfigured by removing the measurement of failed sensor from the measurement vector. If an observability property is preserved after sensor failure, then an inferential control scheme is employed subsequent to the failure. When an actuator failure is isolated, it is proposed to make modifications in the controller objectives or switch to a new controller to account for the loss of a degree of freedom. The efficacy of the proposed failure diagnosis and control structure reconfiguration schemes is demonstrated by conducting experimental studies on a benchmark heater mixer set up. Analysis of these results reveals that the proposed strategies are able to isolate the failures accurately and recover the closed-loop performance by online reconfiguration of the controller/control scheme. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8003122 Exemplaires
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Titre : Role of initial still charge on batch distillation Type de document : texte imprimé Auteurs : Xuemei Zhang, Auteur ; Chungui Jian, Auteur ; Sufei Zhang, Auteur Année de publication : 2009 Article en page(s) : p. 1536–1542 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Chemical industries Batch distillation -- mathematical model Résumé : Batch distillation is widely used in chemical industries, but the role of initial still charge on batch distillation has not been well understood and is still the focus of debate among researchers. A constant molar holdup model for batch distillation was built in this work in order to study the role of initial still charge. The degree of separation difficulty q was used to correlate the design and operating parameters in batch distillation. And yield was selected as the criterion of evaluating the performance of batch distillation under different initial still charge. The simulation results show that an optimum initial charge occurs in batch distillation at q ≤ 0.6 for ideal mixtures. Moreover, the yield keeps constant if the column holdup and initial still charge increase and drop in the same scale with the other operating parameters being fixed. Experiments were made to check the optimum charge with an iso-propanol−n-propanol−n-butanol system, which agreed well with the simulation results. The investigations make it possible to achieve a profitable operation by choosing an optimal amount of charge. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8003607
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1536–1542[article] Role of initial still charge on batch distillation [texte imprimé] / Xuemei Zhang, Auteur ; Chungui Jian, Auteur ; Sufei Zhang, Auteur . - 2009 . - p. 1536–1542.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1536–1542
Mots-clés : Chemical industries Batch distillation -- mathematical model Résumé : Batch distillation is widely used in chemical industries, but the role of initial still charge on batch distillation has not been well understood and is still the focus of debate among researchers. A constant molar holdup model for batch distillation was built in this work in order to study the role of initial still charge. The degree of separation difficulty q was used to correlate the design and operating parameters in batch distillation. And yield was selected as the criterion of evaluating the performance of batch distillation under different initial still charge. The simulation results show that an optimum initial charge occurs in batch distillation at q ≤ 0.6 for ideal mixtures. Moreover, the yield keeps constant if the column holdup and initial still charge increase and drop in the same scale with the other operating parameters being fixed. Experiments were made to check the optimum charge with an iso-propanol−n-propanol−n-butanol system, which agreed well with the simulation results. The investigations make it possible to achieve a profitable operation by choosing an optimal amount of charge. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8003607 Exemplaires
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Titre : NSGA-II for multiobjective optimization of pervaporation process : removal of volatile organics from water Type de document : texte imprimé Auteurs : Gopal R. Nemmani, Auteur ; Satyanarayana V. Suggala, Auteur ; Prashant K. Bhattacharya, Auteur Année de publication : 2009 Article en page(s) : p. 1543–1550 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Pervaporation Process Water -- Volatile Organics wastewater treatment Résumé :
Pervaporation is fast emerging as a viable technique for the removal of VOC from wastewater. In our previous study (Satyanarayana, V. S.; Bhattacharya, P. K. Ind. Eng. Chem. Res. 2003, 42, 3118) we have carried out the minimization of the treatment cost for a fixed toluene removal fraction from multicomponent wastewater by single-stage pervaporation using shell and tube module without recycling permeate. In the present work, two objective optimization problem of minimization of the treatment cost with simultaneous maximization of percent removal of toluene is studied using an evolutionary algorithm of NSGA-II. The previously available model (Satyanarayana, V. S.; Bhattacharya, P. K. Ind. Eng. Chem. Res. 2003, 42, 3118) is employed including fiber diameter as an eighth decision variable. The study reveals that attractive trade-offs are available between the two objectives. Further, vacuum and condensation cost is found to be the major contributor to the treatment cost for the entire range of Reynold’s number and the contribution is found to be more dominating with decrease in Reynold’s number.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8005319
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1543–1550[article] NSGA-II for multiobjective optimization of pervaporation process : removal of volatile organics from water [texte imprimé] / Gopal R. Nemmani, Auteur ; Satyanarayana V. Suggala, Auteur ; Prashant K. Bhattacharya, Auteur . - 2009 . - p. 1543–1550.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1543–1550
Mots-clés : Pervaporation Process Water -- Volatile Organics wastewater treatment Résumé :
Pervaporation is fast emerging as a viable technique for the removal of VOC from wastewater. In our previous study (Satyanarayana, V. S.; Bhattacharya, P. K. Ind. Eng. Chem. Res. 2003, 42, 3118) we have carried out the minimization of the treatment cost for a fixed toluene removal fraction from multicomponent wastewater by single-stage pervaporation using shell and tube module without recycling permeate. In the present work, two objective optimization problem of minimization of the treatment cost with simultaneous maximization of percent removal of toluene is studied using an evolutionary algorithm of NSGA-II. The previously available model (Satyanarayana, V. S.; Bhattacharya, P. K. Ind. Eng. Chem. Res. 2003, 42, 3118) is employed including fiber diameter as an eighth decision variable. The study reveals that attractive trade-offs are available between the two objectives. Further, vacuum and condensation cost is found to be the major contributor to the treatment cost for the entire range of Reynold’s number and the contribution is found to be more dominating with decrease in Reynold’s number.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8005319 Exemplaires
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Titre : Calculation of solubilities for systems containing multiple non-volatile solutes and supercritical carbon dioxide Type de document : texte imprimé Auteurs : Beatriz P. Nobre, Auteur ; Rui L. Mendes, Auteur ; Eduardo M. Queiroz, Auteur Année de publication : 2009 Article en page(s) : p. 1551–1555 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Supercritical fluids Systems non-volatile -- calculation solubility Carbon Dioxide Résumé :
Most of the investigations on thermodynamic modeling of solid solubility in supercritical fluids are limited to pure nonvolatile solutes. Even with a presence of solid mixtures, it is considered that the different solids in the mixture behave as if they were alone, that is, they do not interact. Results in the literature show that this is true if the molecules of the solutes have symmetry, both in size or polarity. The aim of this work is to present solubility experimental data of a solid mixture (β-carotene/bixin) and supercritical carbon dioxide and to propose a thermodynamic model in order to describe this very asymmetric system. The proposed model is based on the Peng−Robinson equation of state and depends on the critical properties and the binary interaction parameters. The binary interaction parameters between carbon dioxide and β-carotene and between carbon dioxide and bixin were obtained from binary experimental data. For the solid mixture and carbon dioxide the model considers interactions between the solids in the solid phase and relaxes the constraint of equal interaction parameters between the solutes. A new set of experimental data on the solubility in supercritical CO2 of a mixture of bixin and β-carotene (1:1, wt) measured at 40 and 60 °C and pressures up to 350 bar is presented, and its behavior is well described by the proposed model, with a deviation of 18.2% and 44.6% for β-carotene and bixin, respectively, opposed to the model without any solid interaction, which poorly describes the available experimental data (approximately 70% average deviation). This model may be used for solid mixtures even when the solids melt.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8006352
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1551–1555[article] Calculation of solubilities for systems containing multiple non-volatile solutes and supercritical carbon dioxide [texte imprimé] / Beatriz P. Nobre, Auteur ; Rui L. Mendes, Auteur ; Eduardo M. Queiroz, Auteur . - 2009 . - p. 1551–1555.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1551–1555
Mots-clés : Supercritical fluids Systems non-volatile -- calculation solubility Carbon Dioxide Résumé :
Most of the investigations on thermodynamic modeling of solid solubility in supercritical fluids are limited to pure nonvolatile solutes. Even with a presence of solid mixtures, it is considered that the different solids in the mixture behave as if they were alone, that is, they do not interact. Results in the literature show that this is true if the molecules of the solutes have symmetry, both in size or polarity. The aim of this work is to present solubility experimental data of a solid mixture (β-carotene/bixin) and supercritical carbon dioxide and to propose a thermodynamic model in order to describe this very asymmetric system. The proposed model is based on the Peng−Robinson equation of state and depends on the critical properties and the binary interaction parameters. The binary interaction parameters between carbon dioxide and β-carotene and between carbon dioxide and bixin were obtained from binary experimental data. For the solid mixture and carbon dioxide the model considers interactions between the solids in the solid phase and relaxes the constraint of equal interaction parameters between the solutes. A new set of experimental data on the solubility in supercritical CO2 of a mixture of bixin and β-carotene (1:1, wt) measured at 40 and 60 °C and pressures up to 350 bar is presented, and its behavior is well described by the proposed model, with a deviation of 18.2% and 44.6% for β-carotene and bixin, respectively, opposed to the model without any solid interaction, which poorly describes the available experimental data (approximately 70% average deviation). This model may be used for solid mixtures even when the solids melt.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8006352 Exemplaires
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Titre : Catalytic wet peroxide oxidation technique for the removal of decontaminating agents ethylenediaminetetraacetic acid and oxalic acid from aqueous solution using efficient fenton type Fe-MCM-41 mesoporous materials Type de document : texte imprimé Auteurs : Narasimhan Gokulakrishnan, Auteur ; Arumugam Pandurangan, Auteur ; Pradeep Kumar Sinha, Auteur Année de publication : 2009 Article en page(s) : p. 1556–1561 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Peroxide Oxidation -- catalytic Ethylenediaminetetraacetic acid Oxalic Waste treatment Résumé :
Catalytic wet peroxide oxidation (CWPO) of organic contaminants may have a possible path for the treatment of decontamination waste containing chelating agents that cause a complex with radioactive cations leading to interferences in their removal by various techniques and may pose a hazard to the environment. The aim of the present work was to synthesize and characterize the mesoporous Fe-MCM-41 with various Si/Fe ratios for evaluating the removal of organic contaminants such as ethylenediaminetetraacetic acid (EDTA) and oxalic acid in aqueous solution. The influence of reaction parameters such as time, pH, and temperature was studied to achieve efficient removal of organic contaminant. Among the catalysts studied, Fe-MCM-41 (Si/Fe = 25) provides high-percentage removal of total organic carbon in aqueous solution. The mineralization of organic contaminants was found to be higher in heterogeneous catalysis than homogeneous catalysis (Fe3+). Further, after the reaction, only a minimum percentage (2%) of Fe was leaching from Fe-MCM-41 under optimized condition and the catalyst remained unaltered in its structure.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800907y
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1556–1561[article] Catalytic wet peroxide oxidation technique for the removal of decontaminating agents ethylenediaminetetraacetic acid and oxalic acid from aqueous solution using efficient fenton type Fe-MCM-41 mesoporous materials [texte imprimé] / Narasimhan Gokulakrishnan, Auteur ; Arumugam Pandurangan, Auteur ; Pradeep Kumar Sinha, Auteur . - 2009 . - p. 1556–1561.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1556–1561
Mots-clés : Peroxide Oxidation -- catalytic Ethylenediaminetetraacetic acid Oxalic Waste treatment Résumé :
Catalytic wet peroxide oxidation (CWPO) of organic contaminants may have a possible path for the treatment of decontamination waste containing chelating agents that cause a complex with radioactive cations leading to interferences in their removal by various techniques and may pose a hazard to the environment. The aim of the present work was to synthesize and characterize the mesoporous Fe-MCM-41 with various Si/Fe ratios for evaluating the removal of organic contaminants such as ethylenediaminetetraacetic acid (EDTA) and oxalic acid in aqueous solution. The influence of reaction parameters such as time, pH, and temperature was studied to achieve efficient removal of organic contaminant. Among the catalysts studied, Fe-MCM-41 (Si/Fe = 25) provides high-percentage removal of total organic carbon in aqueous solution. The mineralization of organic contaminants was found to be higher in heterogeneous catalysis than homogeneous catalysis (Fe3+). Further, after the reaction, only a minimum percentage (2%) of Fe was leaching from Fe-MCM-41 under optimized condition and the catalyst remained unaltered in its structure.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800907y Exemplaires
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Titre : Vanillin release from polysulfone macrocapsules Type de document : texte imprimé Auteurs : Brisa Peña, Auteur ; Mireia Casals, Auteur Année de publication : 2009 Article en page(s) : p. 1562–1565 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Capsules Microencapsulation Macrocapsules -- polysulfone Vanillin macrocapsules Résumé :
Microencapsulation has been successfully implemented in various fields of science. It can be used to remove, protect, preserve and disseminate many substances. The objective of this work is to investigate the vanillin release from polysulfone macrocapsules as a first approach to characterize microcapsules afterward. The capsules were synthesized from polysulfone as polymer, dimethyl formamide as solvent, and vanillin as active agent, by phase inversion precipitation. Morphological characterization was made by scanning electron microscopy. Vanillin release from the capsules was monitored by withdrawing samples, from the release medium, at different time intervals. The vanillin concentration was determined by high performance liquid chromatography. Vanillin release from capsules was encountered to increase when increasing the stirring rate or when increasing the temperature of the release medium. Total amount of vanillin encapsulated was estimated by sequentially refreshing the release medium and corresponded to ca. 50% of the perfume initially incorporated in the polymeric solution.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801133f
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1562–1565[article] Vanillin release from polysulfone macrocapsules [texte imprimé] / Brisa Peña, Auteur ; Mireia Casals, Auteur . - 2009 . - p. 1562–1565.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1562–1565
Mots-clés : Capsules Microencapsulation Macrocapsules -- polysulfone Vanillin macrocapsules Résumé :
Microencapsulation has been successfully implemented in various fields of science. It can be used to remove, protect, preserve and disseminate many substances. The objective of this work is to investigate the vanillin release from polysulfone macrocapsules as a first approach to characterize microcapsules afterward. The capsules were synthesized from polysulfone as polymer, dimethyl formamide as solvent, and vanillin as active agent, by phase inversion precipitation. Morphological characterization was made by scanning electron microscopy. Vanillin release from the capsules was monitored by withdrawing samples, from the release medium, at different time intervals. The vanillin concentration was determined by high performance liquid chromatography. Vanillin release from capsules was encountered to increase when increasing the stirring rate or when increasing the temperature of the release medium. Total amount of vanillin encapsulated was estimated by sequentially refreshing the release medium and corresponded to ca. 50% of the perfume initially incorporated in the polymeric solution.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801133f Exemplaires
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Titre : Limits of operation for the integration of water removal by membranes and crystallization of l-phenylalanine Type de document : texte imprimé Auteurs : Cuellar, Maria C., Auteur ; Simone N. Herreilers, Auteur ; Straathof, Adrie J. J., Auteur Année de publication : 2009 Article en page(s) : p. 1566–1573 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : water Crystallization process Phenylalanine Résumé :
Integration of crystallization and water removal using membrane technology is being used as a means to improve control over supersaturation generation and, consequently, to improve crystal quality. However, it is not clear yet how water removal, which has a limited window of operation, can be combined with crystallization in case of occurrence of several crystal forms (and, therefore, also a limited window of operation). In this work we evaluated the use of nanofiltration and reverse osmosis for water removal to achieve selective crystallization of l-phenylalanine anhydrate from aqueous solution. Water removal and crystallization were first studied separately, and models were used to define the limits of operation for the coupled system so that the target crystal form and production rate could be achieved. A narrow window of operation was obtained, and it was shown that practical implementation can be difficult due to operation near the limits of the window of operation. Possibilities for widening the window of operation are briefly discussed.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8012659
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1566–1573[article] Limits of operation for the integration of water removal by membranes and crystallization of l-phenylalanine [texte imprimé] / Cuellar, Maria C., Auteur ; Simone N. Herreilers, Auteur ; Straathof, Adrie J. J., Auteur . - 2009 . - p. 1566–1573.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1566–1573
Mots-clés : water Crystallization process Phenylalanine Résumé :
Integration of crystallization and water removal using membrane technology is being used as a means to improve control over supersaturation generation and, consequently, to improve crystal quality. However, it is not clear yet how water removal, which has a limited window of operation, can be combined with crystallization in case of occurrence of several crystal forms (and, therefore, also a limited window of operation). In this work we evaluated the use of nanofiltration and reverse osmosis for water removal to achieve selective crystallization of l-phenylalanine anhydrate from aqueous solution. Water removal and crystallization were first studied separately, and models were used to define the limits of operation for the coupled system so that the target crystal form and production rate could be achieved. A narrow window of operation was obtained, and it was shown that practical implementation can be difficult due to operation near the limits of the window of operation. Possibilities for widening the window of operation are briefly discussed.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8012659 Exemplaires
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Titre : Some studies of soybean lipoxygenase-II leaching employing a stirred tank reactor Type de document : texte imprimé Auteurs : Khosrow Rostami, Auteur ; Hamid Bekhteyari, Auteur ; Armita Farahmand, Auteur Année de publication : 2009 Article en page(s) : p. 1574–1578 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Soybean -- Lipoxygenase leaching Résumé :
In the present work, a procedure for leaching of lipoxygenase-II from soybean flour has been developed. The effect of operational parameters such as temperature, mixing speed, pH, sodium salts, leaching period, and reactor scale on enzyme extraction was studied. It has been found that analytical grade n-hexane is more advantageous for defatting of soybean flour than is industrial grade. Further, lipoxygenase-II was leached from defatted soybean flour by using sodium phosphate buffer of 0.05 M strength of pH 6.5. It has also been observed that by increasing the medium temperature from 4 to about 25 ± 1 °C, higher enzyme could be leached. The effect of a wide range of agitator speeds on the enzyme leached was investigated. It has been found that at 5 rps, a considerable amount of lipoxygenase-II could be leached. A vector diagram of the agitated tank and scale-up at 5 and 1.67 rps using CFD has been presented, respectively. Lsqnonlin Matlab version 6.5 was used to analyze the data statistically. A correlation has been developed.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801154z
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1574–1578[article] Some studies of soybean lipoxygenase-II leaching employing a stirred tank reactor [texte imprimé] / Khosrow Rostami, Auteur ; Hamid Bekhteyari, Auteur ; Armita Farahmand, Auteur . - 2009 . - p. 1574–1578.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1574–1578
Mots-clés : Soybean -- Lipoxygenase leaching Résumé :
In the present work, a procedure for leaching of lipoxygenase-II from soybean flour has been developed. The effect of operational parameters such as temperature, mixing speed, pH, sodium salts, leaching period, and reactor scale on enzyme extraction was studied. It has been found that analytical grade n-hexane is more advantageous for defatting of soybean flour than is industrial grade. Further, lipoxygenase-II was leached from defatted soybean flour by using sodium phosphate buffer of 0.05 M strength of pH 6.5. It has also been observed that by increasing the medium temperature from 4 to about 25 ± 1 °C, higher enzyme could be leached. The effect of a wide range of agitator speeds on the enzyme leached was investigated. It has been found that at 5 rps, a considerable amount of lipoxygenase-II could be leached. A vector diagram of the agitated tank and scale-up at 5 and 1.67 rps using CFD has been presented, respectively. Lsqnonlin Matlab version 6.5 was used to analyze the data statistically. A correlation has been developed.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801154z Exemplaires
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Titre : Separation of ethanol-heptane azeotropic mixtures by solvent extraction with an ionic liquid Type de document : texte imprimé Auteurs : Ana B. Pereiro, Auteur ; Ana Rodríguez, Auteur Année de publication : 2009 Article en page(s) : p. 1579–1585 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ionic liquids (ILs) Extraction solvent Ethanol Heptane Résumé :
Ionic liquids (ILs) are gaining attention as potential substitutes for classical organic solvents in extraction processes. This article reports the results of a study on the use of the IL 1,3-dimethylimidazolium methyl sulfate ([MMIM][MeSO4]) as an extraction solvent in petrochemical processes for the removal of heptane from its mixtures with ethanol. The separation of heptane and ethanol is valuable but difficult because of the formation of an azeotropic mixture. Knowledge of the liquid-liquid equilibria (LLE) of this mixture is essential for the design of separation techniques. For this reason, the experimental LLE for the ternary system heptane + ethanol + [MMIM][MeSO4] were investigated at 298.15 K. The solvent capacity of [MMIM][MeSO4] was compared with those of other ILs. The extraction process derived from the use of this solvent was simulated using conventional software, and the obtained results are reported. Experimental data were obtained in a laboratory-scale packed-column extraction system for the separation of this azeotropic mixture using [MMIM][MeSO4]. A comparison with the experimental column data for other ILs is included. Moreover, it is concluded that [MMIM][MeSO4] has the highest extraction efficiency. Also, this IL can be recycled, meaning that the separation process results in a vast reduction of energy consumption.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8011769
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1579–1585[article] Separation of ethanol-heptane azeotropic mixtures by solvent extraction with an ionic liquid [texte imprimé] / Ana B. Pereiro, Auteur ; Ana Rodríguez, Auteur . - 2009 . - p. 1579–1585.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1579–1585
Mots-clés : Ionic liquids (ILs) Extraction solvent Ethanol Heptane Résumé :
Ionic liquids (ILs) are gaining attention as potential substitutes for classical organic solvents in extraction processes. This article reports the results of a study on the use of the IL 1,3-dimethylimidazolium methyl sulfate ([MMIM][MeSO4]) as an extraction solvent in petrochemical processes for the removal of heptane from its mixtures with ethanol. The separation of heptane and ethanol is valuable but difficult because of the formation of an azeotropic mixture. Knowledge of the liquid-liquid equilibria (LLE) of this mixture is essential for the design of separation techniques. For this reason, the experimental LLE for the ternary system heptane + ethanol + [MMIM][MeSO4] were investigated at 298.15 K. The solvent capacity of [MMIM][MeSO4] was compared with those of other ILs. The extraction process derived from the use of this solvent was simulated using conventional software, and the obtained results are reported. Experimental data were obtained in a laboratory-scale packed-column extraction system for the separation of this azeotropic mixture using [MMIM][MeSO4]. A comparison with the experimental column data for other ILs is included. Moreover, it is concluded that [MMIM][MeSO4] has the highest extraction efficiency. Also, this IL can be recycled, meaning that the separation process results in a vast reduction of energy consumption.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8011769 Exemplaires
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Titre : Removal of toxic organic micropollutants with FeTsPc-immobilized amberlite/H2O2 : effect of physicochemical properties of toxic chemicals Type de document : texte imprimé Auteurs : Jae-Hyuk Kim, Auteur ; Se-Joong Kim, Auteur ; Chung-Hak Lee, Auteur Année de publication : 2009 Article en page(s) : p. 1586–1592 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Organic micropollutants -- Physicochemical properties Toxic chemicals FeTsPc-immobilized Résumé :
The effect of physicochemical properties of organic micropollutants on removal efficiencies over iron-tetrasulfophthalocyanine (FeTsPc)-immobilized Amberlite was investigated with one endocrine-disrupting chemical (EDC), bisphenol-A (BPA), and three pharmaceutically active chemicals (PhACs), cefaclor, diclofenac, and ibuprofen. The electrical charge of each chemical was the most important factor in overall removal efficiency. Hydrophilicity was the second most important factor. Negatively charged diclofenac and ibuprofen were completely removed at the reaction pH of 7.5 in less than 1 hour in the absence of H2O2. The FeTsPc-immobilized Amberlite catalyst accelerated BPA and cefaclor removal in the presence of H2O2 at pH 7.5. For BPA, catalytic oxidation accounted for at least 35% of total removal. The stability of FeTsPc was greatly improved by immobilizing it on Amberlite compared to that of the homogeneous FeTsPc in an aqueous solutionEn ligne : http://pubs.acs.org/doi/abs/10.1021/ie071412k
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1586–1592[article] Removal of toxic organic micropollutants with FeTsPc-immobilized amberlite/H2O2 : effect of physicochemical properties of toxic chemicals [texte imprimé] / Jae-Hyuk Kim, Auteur ; Se-Joong Kim, Auteur ; Chung-Hak Lee, Auteur . - 2009 . - p. 1586–1592.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1586–1592
Mots-clés : Organic micropollutants -- Physicochemical properties Toxic chemicals FeTsPc-immobilized Résumé :
The effect of physicochemical properties of organic micropollutants on removal efficiencies over iron-tetrasulfophthalocyanine (FeTsPc)-immobilized Amberlite was investigated with one endocrine-disrupting chemical (EDC), bisphenol-A (BPA), and three pharmaceutically active chemicals (PhACs), cefaclor, diclofenac, and ibuprofen. The electrical charge of each chemical was the most important factor in overall removal efficiency. Hydrophilicity was the second most important factor. Negatively charged diclofenac and ibuprofen were completely removed at the reaction pH of 7.5 in less than 1 hour in the absence of H2O2. The FeTsPc-immobilized Amberlite catalyst accelerated BPA and cefaclor removal in the presence of H2O2 at pH 7.5. For BPA, catalytic oxidation accounted for at least 35% of total removal. The stability of FeTsPc was greatly improved by immobilizing it on Amberlite compared to that of the homogeneous FeTsPc in an aqueous solutionEn ligne : http://pubs.acs.org/doi/abs/10.1021/ie071412k Exemplaires
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Titre : Electrochemical mass transfer in impinging swirl jets Type de document : texte imprimé Auteurs : Atatürk Üniversitesi, Auteur ; Mühendislik Fakültesi, Auteur ; Kimya Mühendisliği Bölümü, Auteur Année de publication : 2009 Article en page(s) : p. 1593–1602 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Electrochemical Jets -- Mass transfer Résumé :
The local mass transfer coefficients between an impinging swirl jet flow and a flat circular surface in a cylindrical cell were measured by the electrochemical limiting diffusion current technique. Helical-type swirl generators were used to generate swirl flow with intensities in the range of S = 0−0.73. The experiments were carried out for a jet Reynolds number range of 10 950−43 800, a nozzle-to-surface distance range of 2−10, and a dimensionless radial distance range of 0−15. The measured local mass transfer distributions in the radial direction exhibited an increase first and then a decrease and a converging behavior as the radial distance increased. It was observed that increasing Reynolds number increased the mass transfer rate, but its effect was reduced with an increase in swirl intensity. Increasing swirl intensity decreased transfer coefficients but increased their uniformity over the disk surface. The change in the nozzle-to-surface distance affected mass transfer coefficients up to a dimensionless radial distance of approximately r/djEn ligne : http://pubs.acs.org/doi/abs/10.1021/ie0715097
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1593–1602[article] Electrochemical mass transfer in impinging swirl jets [texte imprimé] / Atatürk Üniversitesi, Auteur ; Mühendislik Fakültesi, Auteur ; Kimya Mühendisliği Bölümü, Auteur . - 2009 . - p. 1593–1602.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1593–1602
Mots-clés : Electrochemical Jets -- Mass transfer Résumé :
The local mass transfer coefficients between an impinging swirl jet flow and a flat circular surface in a cylindrical cell were measured by the electrochemical limiting diffusion current technique. Helical-type swirl generators were used to generate swirl flow with intensities in the range of S = 0−0.73. The experiments were carried out for a jet Reynolds number range of 10 950−43 800, a nozzle-to-surface distance range of 2−10, and a dimensionless radial distance range of 0−15. The measured local mass transfer distributions in the radial direction exhibited an increase first and then a decrease and a converging behavior as the radial distance increased. It was observed that increasing Reynolds number increased the mass transfer rate, but its effect was reduced with an increase in swirl intensity. Increasing swirl intensity decreased transfer coefficients but increased their uniformity over the disk surface. The change in the nozzle-to-surface distance affected mass transfer coefficients up to a dimensionless radial distance of approximately r/djEn ligne : http://pubs.acs.org/doi/abs/10.1021/ie0715097 Exemplaires
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Titre : Reaction chemistry between aqueous sulfuric acid and solid sodium borohydride Type de document : texte imprimé Auteurs : Qinglin Zhang, Auteur ; Richard M. Mohring, Auteur Année de publication : 2009 Article en page(s) : p. 1603–1607 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Chemical hydrides Sulfuric acid -- reaction chemistry Solid sodium borohydride Résumé :
Chemical hydrides represent a class of promising hydrogen storage materials. Solid sodium borohydride in particular offers superior fuel stability and its reaction with acid provides a new approach for hydrogen generation. In this study, the chemistry involved in a hydrogen storage system based on solid NaBH4 and aqueous H2SO4 was studied experimentally. Factors influencing hydrogen generation dynamics, sodium borohydride conversion, and borax byproduct distributions were studied. A fuel-only energy density of 2310 Wh/kg (on the basis of lower heating value of hydrogen contained) is projected for hydrogen storage using pure sodium borohydride and 31 wt % H2SO4.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800470d
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1603–1607[article] Reaction chemistry between aqueous sulfuric acid and solid sodium borohydride [texte imprimé] / Qinglin Zhang, Auteur ; Richard M. Mohring, Auteur . - 2009 . - p. 1603–1607.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1603–1607
Mots-clés : Chemical hydrides Sulfuric acid -- reaction chemistry Solid sodium borohydride Résumé :
Chemical hydrides represent a class of promising hydrogen storage materials. Solid sodium borohydride in particular offers superior fuel stability and its reaction with acid provides a new approach for hydrogen generation. In this study, the chemistry involved in a hydrogen storage system based on solid NaBH4 and aqueous H2SO4 was studied experimentally. Factors influencing hydrogen generation dynamics, sodium borohydride conversion, and borax byproduct distributions were studied. A fuel-only energy density of 2310 Wh/kg (on the basis of lower heating value of hydrogen contained) is projected for hydrogen storage using pure sodium borohydride and 31 wt % H2SO4.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800470d Exemplaires
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Titre : Computational fluid dynamics simulation of solid suspension in a gas-liquid-solid mechanically agitated contactor Type de document : texte imprimé Auteurs : Ranganathan Panneerselvam, Auteur ; Sivaraman Savithri, Auteur ; Gerald Devasagayam Surender, Auteur Année de publication : 2009 Article en page(s) : p. 1608–1620 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Fluid dynamics Gas-liquid Gas-solid Solid suspension Résumé :
In the present study, computational fluid dynamics (CFD) simulations have been carried out to characterize a solid suspension in a gas-liquid-solid mechanically agitated contactor using the Eulerian multifluid approach with a standard k-ε turbulence model. A steady state method of multiple frame of reference (MFR) has been used to model the impeller and tank region. The CFD model predictions are compared qualitatively with the literature experimental data (Guha et al. Chem. Eng. Sci. 2007, 62, 6143; Spidla et al. Chem. Eng. J. 2005, 113, 73; Aubin et al. Exp. Therm. Fluid Sci. 2004, 28, 447) and quantitatively with our experimental data. Also the effect of different types of impellers (disk turbine and pitched blade turbine with downward pumping), impeller speed, particle size (125−230 μm), and gas flow rate (0-1 vvm) on the critical impeller speed for solid suspension in a gas-liquid-solid mechanically agitated contactor is investigated. The values predicted by CFD simulation agree well with experimental data for various operating conditions.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800978w
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1608–1620[article] Computational fluid dynamics simulation of solid suspension in a gas-liquid-solid mechanically agitated contactor [texte imprimé] / Ranganathan Panneerselvam, Auteur ; Sivaraman Savithri, Auteur ; Gerald Devasagayam Surender, Auteur . - 2009 . - p. 1608–1620.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1608–1620
Mots-clés : Fluid dynamics Gas-liquid Gas-solid Solid suspension Résumé :
In the present study, computational fluid dynamics (CFD) simulations have been carried out to characterize a solid suspension in a gas-liquid-solid mechanically agitated contactor using the Eulerian multifluid approach with a standard k-ε turbulence model. A steady state method of multiple frame of reference (MFR) has been used to model the impeller and tank region. The CFD model predictions are compared qualitatively with the literature experimental data (Guha et al. Chem. Eng. Sci. 2007, 62, 6143; Spidla et al. Chem. Eng. J. 2005, 113, 73; Aubin et al. Exp. Therm. Fluid Sci. 2004, 28, 447) and quantitatively with our experimental data. Also the effect of different types of impellers (disk turbine and pitched blade turbine with downward pumping), impeller speed, particle size (125−230 μm), and gas flow rate (0-1 vvm) on the critical impeller speed for solid suspension in a gas-liquid-solid mechanically agitated contactor is investigated. The values predicted by CFD simulation agree well with experimental data for various operating conditions.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800978w Exemplaires
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Titre : Flow pattern, pressure drop, and mass transfer in a gas-liquid concurrent two-phase flow microchannel reactor Type de document : texte imprimé Auteurs : Haining Niu, Auteur ; Liwei Pan, Auteur ; Hongjiu Su, Auteur Année de publication : 2009 Article en page(s) : p. 1621–1628 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Gas-liquid -- pressure drop mass transfer flow pattern Résumé :
Flow pattern, pressure drop, and mass transfer characteristics have been studied for the gas-liquid two-phase flow in a 1.0 mm inner diameter circular microchannel reactor. A mixture of CO2, N2, and polyethylene glycol dimethyl ether was used to represent the gas and liquid phases, respectively. Bubbly, slug, churn, and slug-annular flow patterns were observed in the present work. A flow pattern map using superficial gas and liquid velocities as coordinates has been developed and compared to the existing flow pattern maps for ∼1 mm diameter channels. The data obtained for the pressure drop of the two-phase flow were analyzed and compared with the homogeneous model and the separate flow model to assess their predictive capabilities. The liquid side volumetric mass transfer coefficient increased with an increase of the superficial gas and liquid velocities, and the influences of the superficial gas and liquid velocities on it were demonstrated. The liquid side mass transfer coefficient, which was as high as 3.34 s-1, was 1 or 2 orders of magnitude higher than the traditional industrial gas−liquid contactors.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801095a
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1621–1628[article] Flow pattern, pressure drop, and mass transfer in a gas-liquid concurrent two-phase flow microchannel reactor [texte imprimé] / Haining Niu, Auteur ; Liwei Pan, Auteur ; Hongjiu Su, Auteur . - 2009 . - p. 1621–1628.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1621–1628
Mots-clés : Gas-liquid -- pressure drop mass transfer flow pattern Résumé :
Flow pattern, pressure drop, and mass transfer characteristics have been studied for the gas-liquid two-phase flow in a 1.0 mm inner diameter circular microchannel reactor. A mixture of CO2, N2, and polyethylene glycol dimethyl ether was used to represent the gas and liquid phases, respectively. Bubbly, slug, churn, and slug-annular flow patterns were observed in the present work. A flow pattern map using superficial gas and liquid velocities as coordinates has been developed and compared to the existing flow pattern maps for ∼1 mm diameter channels. The data obtained for the pressure drop of the two-phase flow were analyzed and compared with the homogeneous model and the separate flow model to assess their predictive capabilities. The liquid side volumetric mass transfer coefficient increased with an increase of the superficial gas and liquid velocities, and the influences of the superficial gas and liquid velocities on it were demonstrated. The liquid side mass transfer coefficient, which was as high as 3.34 s-1, was 1 or 2 orders of magnitude higher than the traditional industrial gas−liquid contactors.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801095a Exemplaires
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Titre : Development of a countercurrent multistage fluidized-bed reactor and mathematical modeling for prediction of removal efficiency of sulfur dioxide from flue gases Type de document : texte imprimé Auteurs : C. R. Mohanty, Auteur ; G. Malavia, Auteur ; B. C. Meikap, Auteur Année de publication : 2009 Article en page(s) : p. 1629–1637 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Flue Gases -- sulfur dioxide Fluidization mathematical modeling Résumé :
A bubbling countercurrent multistage fluidized-bed reactor for the sorption of sulfur dioxide by hydrated lime particles was simulated employing a two-phase model, with the bubble phase assumed to be in plug flow and with the emulsion phase either in plug flow (EGPF model) or in perfectly mixed flow (EGPM model). The model calculations were compared with experimental data in term of percentage removal efficiency of sulfur dioxide. Both models were applied to understand the influence of operating parameters on the reactor performance. The comparison showed that the EGPF model agreed well with the experimental data. From the perspective of use of a multistage fluidized-bed reactor as air pollution control equipment in industry, the model could be considered general enough for predicting the performance of reactors for gas−solid treatment.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801615c
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1629–1637[article] Development of a countercurrent multistage fluidized-bed reactor and mathematical modeling for prediction of removal efficiency of sulfur dioxide from flue gases [texte imprimé] / C. R. Mohanty, Auteur ; G. Malavia, Auteur ; B. C. Meikap, Auteur . - 2009 . - p. 1629–1637.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1629–1637
Mots-clés : Flue Gases -- sulfur dioxide Fluidization mathematical modeling Résumé :
A bubbling countercurrent multistage fluidized-bed reactor for the sorption of sulfur dioxide by hydrated lime particles was simulated employing a two-phase model, with the bubble phase assumed to be in plug flow and with the emulsion phase either in plug flow (EGPF model) or in perfectly mixed flow (EGPM model). The model calculations were compared with experimental data in term of percentage removal efficiency of sulfur dioxide. Both models were applied to understand the influence of operating parameters on the reactor performance. The comparison showed that the EGPF model agreed well with the experimental data. From the perspective of use of a multistage fluidized-bed reactor as air pollution control equipment in industry, the model could be considered general enough for predicting the performance of reactors for gas−solid treatment.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801615c Exemplaires
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Titre : The effect of oven-heat flux on powder-coating issues of sheet molding compound panels Type de document : texte imprimé Auteurs : Soumendra K. Basu, Auteur ; Bhavesh Shah, Auteur ; Hamid G. Kia, Auteur Année de publication : 2009 Article en page(s) : p. 1638–1649 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Powder-coating Powder bake Oven-Heat -- effect Résumé :
The effects of variations in the powder bake temperature profile on the paint popping defect of sheet molding compound (SMC) panels was investigated by subjecting powder-coated panels to various heating rates using IR heaters and convective ovens, and by using a mathematical model of heat transfer and curing reaction. It was found that overheating the SMC than that required for optimum powder curing can cause high rates of outgassing of absorbed moisture and, therefore, excessive popping. It was further found that higher quantity of moisture outgassing per unit time through the molten primer layer during a fast temperature ramp causes more popping compared to a slow temperature ramp. Therefore, it is expected that any plant that is experiencing paint popping would benefit from slowing down the rate of temperature rise of the panels during the initial 5−10 min of the heating cycle.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801130g
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1638–1649[article] The effect of oven-heat flux on powder-coating issues of sheet molding compound panels [texte imprimé] / Soumendra K. Basu, Auteur ; Bhavesh Shah, Auteur ; Hamid G. Kia, Auteur . - 2009 . - p. 1638–1649.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1638–1649
Mots-clés : Powder-coating Powder bake Oven-Heat -- effect Résumé :
The effects of variations in the powder bake temperature profile on the paint popping defect of sheet molding compound (SMC) panels was investigated by subjecting powder-coated panels to various heating rates using IR heaters and convective ovens, and by using a mathematical model of heat transfer and curing reaction. It was found that overheating the SMC than that required for optimum powder curing can cause high rates of outgassing of absorbed moisture and, therefore, excessive popping. It was further found that higher quantity of moisture outgassing per unit time through the molten primer layer during a fast temperature ramp causes more popping compared to a slow temperature ramp. Therefore, it is expected that any plant that is experiencing paint popping would benefit from slowing down the rate of temperature rise of the panels during the initial 5−10 min of the heating cycle.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801130g Exemplaires
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Titre : Degradation of chemical warfare agents by reactive polymers Type de document : texte imprimé Auteurs : Lev Bromberg, Auteur ; Heidi Schreuder-Gibson, Auteur ; William R. Creasy, Auteur Année de publication : 2009 Article en page(s) : p. 1650–1659 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Chemical warfare -- Degradation Reactive polymers Résumé : Nucleophilic hydrolysis of chemical warfare agents (CWA), S-2-(diisopropylamino)ethyl O-ethyl methylphosphonothioate (VX), O-pinacolyl methylphosphonofluoridate (soman, or GD), and isopropyl methylphosphonofluoridate (sarin, or GB) by polyacrylamidoxime (PANOx) and poly(N-hydroxyacrylamide) (PHA) has been demonstrated. The reactive PANOx and PHA were obtained by one-step oximation of polyacrylonitrile and polyacrylamide, respectively. The polymers were converted to their respective oximate salts at pH values greater than the pKa of oximate or amidoximate groups of 7.5 and 10.8, respectively. Although the PANOx and PHA exhibited spontaneous hydrolysis at ambient temperature and humidity, the conversion of the hydroxamate into the unreactive carboxylic groups was insignificant even at prolonged storage, so that the polymers maintained reactivity at ambient conditions. When exposed to ambient air or 100% humidity, the polymers imbibed up to 65 wt % water, which dramatically enhanced the polymer reactivity toward the CWA under study. The half-lives of VX in heterogeneous hydrolysis, which appeared to be pseudo-first-order in the polymer dispersions, were measured to be from 0.093 to 4.3 and 7.7 h in the presence of PANOx and PHA, respectively. The rates of hydrolytic activity of PANOx for VX exhibited a strong dependency on the degree of conversion of the amidoxime to amidoximate groups. The half-life of GB was less than 3 min. Only a minor presence of the toxic VX degradation product, S-[2-(diisopropylamino)ethyl]methylphonothioate (EA-2192), was detected in the course of degradation by the reactive polymers. The efficiency, ease of synthesis, and nontoxic nature of the PANOx and PHA polymers make them attractive materials in decontamination and as components of reactive barriers. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801150y
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1650–1659[article] Degradation of chemical warfare agents by reactive polymers [texte imprimé] / Lev Bromberg, Auteur ; Heidi Schreuder-Gibson, Auteur ; William R. Creasy, Auteur . - 2009 . - p. 1650–1659.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1650–1659
Mots-clés : Chemical warfare -- Degradation Reactive polymers Résumé : Nucleophilic hydrolysis of chemical warfare agents (CWA), S-2-(diisopropylamino)ethyl O-ethyl methylphosphonothioate (VX), O-pinacolyl methylphosphonofluoridate (soman, or GD), and isopropyl methylphosphonofluoridate (sarin, or GB) by polyacrylamidoxime (PANOx) and poly(N-hydroxyacrylamide) (PHA) has been demonstrated. The reactive PANOx and PHA were obtained by one-step oximation of polyacrylonitrile and polyacrylamide, respectively. The polymers were converted to their respective oximate salts at pH values greater than the pKa of oximate or amidoximate groups of 7.5 and 10.8, respectively. Although the PANOx and PHA exhibited spontaneous hydrolysis at ambient temperature and humidity, the conversion of the hydroxamate into the unreactive carboxylic groups was insignificant even at prolonged storage, so that the polymers maintained reactivity at ambient conditions. When exposed to ambient air or 100% humidity, the polymers imbibed up to 65 wt % water, which dramatically enhanced the polymer reactivity toward the CWA under study. The half-lives of VX in heterogeneous hydrolysis, which appeared to be pseudo-first-order in the polymer dispersions, were measured to be from 0.093 to 4.3 and 7.7 h in the presence of PANOx and PHA, respectively. The rates of hydrolytic activity of PANOx for VX exhibited a strong dependency on the degree of conversion of the amidoxime to amidoximate groups. The half-life of GB was less than 3 min. Only a minor presence of the toxic VX degradation product, S-[2-(diisopropylamino)ethyl]methylphonothioate (EA-2192), was detected in the course of degradation by the reactive polymers. The efficiency, ease of synthesis, and nontoxic nature of the PANOx and PHA polymers make them attractive materials in decontamination and as components of reactive barriers. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801150y Exemplaires
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Titre : Modified resin coalescer for oil-in-water emulsion treatment : effect of operating conditions on oil removal performance Type de document : texte imprimé Auteurs : Yan Bo Zhou, Auteur ; Chen, Li, Auteur ; Xiao Meng Hu, Auteur Année de publication : 2009 Article en page(s) : p. 1660–1664 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Resin Oil Coalescence material Résumé :
The application of modified resin as a filter medium treating the anionic surfactant stabilized oil-in-water emulsion was investigated. In this study, emulsion breaking was accelerated by the grafting cetyltrimethylammonium bromide on polystyrene resin, so the need for expensive specific chemicals was eliminated. The results indicated that, as a new type of coalescence material, the modified resin has incomparable advantages over polypropylene, ceramic, and activated carbon. A series of experiments were performed to evaluate the effect of flow velocity, bed height, oil concentration, temperature, and pH value on the oil removal performance of the modified resin coalescer. More than 80% of emulsified oil was removed under optimal operating conditions: flow velocity 60-180 mL/h, bed height 20-40 cm, temperature 20-60 °C, and pH value 2-10. The results further indicated that modified resin bed coalescer is feasible to be used in the treatment of oil-in-water emulsion due to integration of both advantages of chemical demulsification and coalescence process.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8012242
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1660–1664[article] Modified resin coalescer for oil-in-water emulsion treatment : effect of operating conditions on oil removal performance [texte imprimé] / Yan Bo Zhou, Auteur ; Chen, Li, Auteur ; Xiao Meng Hu, Auteur . - 2009 . - p. 1660–1664.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1660–1664
Mots-clés : Resin Oil Coalescence material Résumé :
The application of modified resin as a filter medium treating the anionic surfactant stabilized oil-in-water emulsion was investigated. In this study, emulsion breaking was accelerated by the grafting cetyltrimethylammonium bromide on polystyrene resin, so the need for expensive specific chemicals was eliminated. The results indicated that, as a new type of coalescence material, the modified resin has incomparable advantages over polypropylene, ceramic, and activated carbon. A series of experiments were performed to evaluate the effect of flow velocity, bed height, oil concentration, temperature, and pH value on the oil removal performance of the modified resin coalescer. More than 80% of emulsified oil was removed under optimal operating conditions: flow velocity 60-180 mL/h, bed height 20-40 cm, temperature 20-60 °C, and pH value 2-10. The results further indicated that modified resin bed coalescer is feasible to be used in the treatment of oil-in-water emulsion due to integration of both advantages of chemical demulsification and coalescence process.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8012242 Exemplaires
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Titre : Turbulent and laminar mixings in an unbaffled agitated vessel with an unsteadily angularly oscillating impeller Type de document : texte imprimé Auteurs : Masanori Yoshida, Auteur ; Yasuyuki Nagai, Auteur ; Kazuaki Yamagiwa, Auteur Année de publication : 2009 Article en page(s) : p. 1665–1672 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Oscillation Vessel agitated Impeller power Résumé :
For an unbaffled agitated vessel with an angularly oscillating impeller whose rotation continues while periodically reversing its direction at a set angle, the progress of mixing of Newtonian liquid phase was studied experimentally in relation to the impeller power characteristics. Results obtained for the angular oscillation mode of a disk turbine impeller with six flat blades with different amplitudes (Strouhal number) were compared to those obtained for the unidirectional rotation mode of the impeller of identical design. Using an angularly oscillating impeller, turbulent and laminar mixings were effective, respectively, with larger and smaller amplitudes. The mixing characteristics for turbulent and laminar flow regions were discussed on the basis of the flow field features, which the impeller power number reflected.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801502q
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1665–1672[article] Turbulent and laminar mixings in an unbaffled agitated vessel with an unsteadily angularly oscillating impeller [texte imprimé] / Masanori Yoshida, Auteur ; Yasuyuki Nagai, Auteur ; Kazuaki Yamagiwa, Auteur . - 2009 . - p. 1665–1672.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1665–1672
Mots-clés : Oscillation Vessel agitated Impeller power Résumé :
For an unbaffled agitated vessel with an angularly oscillating impeller whose rotation continues while periodically reversing its direction at a set angle, the progress of mixing of Newtonian liquid phase was studied experimentally in relation to the impeller power characteristics. Results obtained for the angular oscillation mode of a disk turbine impeller with six flat blades with different amplitudes (Strouhal number) were compared to those obtained for the unidirectional rotation mode of the impeller of identical design. Using an angularly oscillating impeller, turbulent and laminar mixings were effective, respectively, with larger and smaller amplitudes. The mixing characteristics for turbulent and laminar flow regions were discussed on the basis of the flow field features, which the impeller power number reflected.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801502q Exemplaires
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Titre : Synthesis of glycerol-based pyridinium surfactants and appraisal of their properties Type de document : texte imprimé Auteurs : Sukhprit Singh, Auteur ; Avinash Bhadani, Auteur ; Hardeep Kataria, Auteur Année de publication : 2009 Article en page(s) : p. 1673–1677 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Glycerol Pyridinium Cationic surfactants Résumé : β-Bromo glycerol monoethers, when heated with pyridine at 100 °C for 10 h, gave a new glycerol-based pyridinium cationic surfactant, 1-(1-(2,3-dihydroxypropoxy)alkane-2-yl)pyridinium bromide (6a-10a)/1-(2-(2,3-dihydroxypropoxy)alkyl)pyridinium bromide (6b-10b) in a yield of 60%-70%. The surface properties and biocompatibility of these cationic surfactants has been determined and compared to tetradecyl trimethyl ammonium bromide (10) and cetyl pyridinium bromide (11). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801737m
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1673–1677[article] Synthesis of glycerol-based pyridinium surfactants and appraisal of their properties [texte imprimé] / Sukhprit Singh, Auteur ; Avinash Bhadani, Auteur ; Hardeep Kataria, Auteur . - 2009 . - p. 1673–1677.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1673–1677
Mots-clés : Glycerol Pyridinium Cationic surfactants Résumé : β-Bromo glycerol monoethers, when heated with pyridine at 100 °C for 10 h, gave a new glycerol-based pyridinium cationic surfactant, 1-(1-(2,3-dihydroxypropoxy)alkane-2-yl)pyridinium bromide (6a-10a)/1-(2-(2,3-dihydroxypropoxy)alkyl)pyridinium bromide (6b-10b) in a yield of 60%-70%. The surface properties and biocompatibility of these cationic surfactants has been determined and compared to tetradecyl trimethyl ammonium bromide (10) and cetyl pyridinium bromide (11). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801737m Exemplaires
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Titre : Estimation of aniline point temperature of pure hydrocarbons : a quantitative structure-property relationship approach Type de document : texte imprimé Auteurs : Farhad Gharagheizi, Auteur ; Behnam Tirandazi, Auteur ; Reza Barzin, Auteur Année de publication : 2009 Article en page(s) : p. 1678–1682 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Aniline Hydrocarbons Structure -- quantitative study Material physicochemical properties Résumé :
In the present work, a quantitative structure-property relationship (QSPR) study is performed to predict the aniline point temperature of pure hydrocarbon components. As a powerful tool, genetic algorithm-based multivariate linear regression (GA-MLR) is applied to select most statistically effective molecular descriptors on the aniline point temperature of pure hydrocarbon components. Also, a three-layer feed forward neural network (FFNN) is constructed to consider the nonlinear behavior of appearing molecular descriptors in GA-MLR result. The obtained results show that the constructed FFNN can accurately predict the aniline point temperature of pure hydrocarbon components.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801212a
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1678–1682[article] Estimation of aniline point temperature of pure hydrocarbons : a quantitative structure-property relationship approach [texte imprimé] / Farhad Gharagheizi, Auteur ; Behnam Tirandazi, Auteur ; Reza Barzin, Auteur . - 2009 . - p. 1678–1682.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1678–1682
Mots-clés : Aniline Hydrocarbons Structure -- quantitative study Material physicochemical properties Résumé :
In the present work, a quantitative structure-property relationship (QSPR) study is performed to predict the aniline point temperature of pure hydrocarbon components. As a powerful tool, genetic algorithm-based multivariate linear regression (GA-MLR) is applied to select most statistically effective molecular descriptors on the aniline point temperature of pure hydrocarbon components. Also, a three-layer feed forward neural network (FFNN) is constructed to consider the nonlinear behavior of appearing molecular descriptors in GA-MLR result. The obtained results show that the constructed FFNN can accurately predict the aniline point temperature of pure hydrocarbon components.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801212a Exemplaires
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