Dépouillements

Thermodynamic property modeling for chemical process and product engineering / John P. O’Connell in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4619–4637 Titre : Thermodynamic property modeling for chemical process and product engineering : some perspectives Type de document : texte imprimé Auteurs : John P. O’Connell, Auteur ; Rafiqul Gani, Auteur ; Paul M. Mathias, Auteur Année de publication : 2009 Article en page(s) : pp. 4619–4637 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Thermodynamics Chemical products Résumé : Thermodynamic properties have always played essential roles in the engineering of chemical products and in the processes that manufacture them. Further, contemporary and future chemical technologies depend more than ever on property model formulation and application. This work explores how properties are utilized in process and product engineering, including opportunities and constraints of current property models, the current status of data availability and needs, and the interplay of data and models. Several case studies are given to illustrate underlying concepts, strategies for development, and methods of application to some industrial systems. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801535a [article] Thermodynamic property modeling for chemical process and product engineering : some perspectives [texte imprimé] / John P. O’Connell, Auteur ; Rafiqul Gani, Auteur ; Paul M. Mathias, Auteur . - 2009 . - pp. 4619–4637. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4619–4637 Mots-clés : Thermodynamics Chemical products Résumé : Thermodynamic properties have always played essential roles in the engineering of chemical products and in the processes that manufacture them. Further, contemporary and future chemical technologies depend more than ever on property model formulation and application. This work explores how properties are utilized in process and product engineering, including opportunities and constraints of current property models, the current status of data availability and needs, and the interplay of data and models. Several case studies are given to illustrate underlying concepts, strategies for development, and methods of application to some industrial systems. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801535a

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Membrane gas separation / P. Bernardo in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4638–4663 Titre : Membrane gas separation : a review/state of the art Type de document : texte imprimé Auteurs : P. Bernardo, Auteur ; E. Drioli, Auteur ; G. Golemme, Auteur Année de publication : 2009 Article en page(s) : pp. 4638–4663 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Gas separation Membrane processes Swing absorption Sryogenic distillation Résumé : In the last years membrane processes for gas separation are gaining a larger acceptance in industry and in the market are competing with consolidated operations such as pressure swing absorption and cryogenic distillation. The key for new applications of membranes in challenging and harsh environments (e.g., petrochemistry) is the development of new tough, high performance materials. The modular nature of membrane operations is intrinsically fit for process intensification, and this versatility might be a decisive factor to impose membrane processes in most gas separation fields, in a similar way as today membranes represent the main technology for water treatment. This review highlights the most promising areas of research in gas separation, by considering the materials for membranes, the industrial applications of membrane gas separations, and finally the opportunities for the integration of membrane gas separation units in hybrid systems for the intensification of processes. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8019032 [article] Membrane gas separation : a review/state of the art [texte imprimé] / P. Bernardo, Auteur ; E. Drioli, Auteur ; G. Golemme, Auteur . - 2009 . - pp. 4638–4663. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4638–4663 Mots-clés : Gas separation Membrane processes Swing absorption Sryogenic distillation Résumé : In the last years membrane processes for gas separation are gaining a larger acceptance in industry and in the market are competing with consolidated operations such as pressure swing absorption and cryogenic distillation. The key for new applications of membranes in challenging and harsh environments (e.g., petrochemistry) is the development of new tough, high performance materials. The modular nature of membrane operations is intrinsically fit for process intensification, and this versatility might be a decisive factor to impose membrane processes in most gas separation fields, in a similar way as today membranes represent the main technology for water treatment. This review highlights the most promising areas of research in gas separation, by considering the materials for membranes, the industrial applications of membrane gas separations, and finally the opportunities for the integration of membrane gas separation units in hybrid systems for the intensification of processes. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8019032

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Activation of waste tire char upon cyclic oxygen chemisorption-desorption / Francisco Heras in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4664–4670 Titre : Activation of waste tire char upon cyclic oxygen chemisorption-desorption Type de document : texte imprimé Auteurs : Francisco Heras, Auteur ; Noelia Alasino, Auteur ; Miguel A. Gilarranz, Auteur Année de publication : 2009 Article en page(s) : pp. 4664–4670 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Waste tire char Chemisorption−  desorption BET surface Résumé : Activation of waste tire char upon cyclic oxygen chemisorption−desorption permits a controlled development of porosity versus burnoff using air as feed gas for the activation process. A slow but monotonical increase of BET surface area is obtained from cycle to cycle. Initially the process led to the development of mesoporosity without generating micropores and then the micropore volume is increased whereas a decrease of narrow mesopore (20−80 nm) volume is observed, probably as a consequence of mesopore widening. Although the SBET reaches relatively low values (below 250 m2/g) even after 15 cycles, this surface development is associated with low burnoff values (around 22% for indicated BET surface area) and corresponds in an important percentage (up to about 50%) to external (nonmicropore) area. Temperatures around 210 and 550 °C for chemisorption and desorption, respectively, have been found as optimum for the purpose of preparing granular mesoporous carbons which can be interesting candidates as catalytic supports for liquid phase applications. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801764x [article] Activation of waste tire char upon cyclic oxygen chemisorption-desorption [texte imprimé] / Francisco Heras, Auteur ; Noelia Alasino, Auteur ; Miguel A. Gilarranz, Auteur . - 2009 . - pp. 4664–4670. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4664–4670 Mots-clés : Waste tire char Chemisorption−  desorption BET surface Résumé : Activation of waste tire char upon cyclic oxygen chemisorption−desorption permits a controlled development of porosity versus burnoff using air as feed gas for the activation process. A slow but monotonical increase of BET surface area is obtained from cycle to cycle. Initially the process led to the development of mesoporosity without generating micropores and then the micropore volume is increased whereas a decrease of narrow mesopore (20−80 nm) volume is observed, probably as a consequence of mesopore widening. Although the SBET reaches relatively low values (below 250 m2/g) even after 15 cycles, this surface development is associated with low burnoff values (around 22% for indicated BET surface area) and corresponds in an important percentage (up to about 50%) to external (nonmicropore) area. Temperatures around 210 and 550 °C for chemisorption and desorption, respectively, have been found as optimum for the purpose of preparing granular mesoporous carbons which can be interesting candidates as catalytic supports for liquid phase applications. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801764x

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Regioselective synthesis of monoepoxides from terpenic diolefins over alumina at high temperature and pressure / María A. Uguina in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4671–4680 Titre : Regioselective synthesis of monoepoxides from terpenic diolefins over alumina at high temperature and pressure Type de document : texte imprimé Auteurs : María A. Uguina, Auteur ; José A. Delgado, Auteur ; José Carretero, Auteur Année de publication : 2009 Article en page(s) : pp. 4671–4680 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Alumina Terpenic diolefins Epoxidation Water Résumé : Alumina is a heterogeneous catalyst for the regioselective epoxidation of terpenic diolefins that deactivates in presence of water. The reactions can be carried out at high temperature, above the boiling point of the solvent, increasing the pressure to maintain the reaction mixture in the liquid phase, yielding conversions between 41% and 96% and selectivities between 19% and 75% to monoepoxides with a significant decrease of reaction times. Deactivated alumina was analyzed, and an effective regeneration method was proposed. Furthermore, to improve the monoepoxide productivity, the effects of temperature, pressure, stirring rate, water concentration, alumina loading, and reactive concentrations were studied. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801763e [article] Regioselective synthesis of monoepoxides from terpenic diolefins over alumina at high temperature and pressure [texte imprimé] / María A. Uguina, Auteur ; José A. Delgado, Auteur ; José Carretero, Auteur . - 2009 . - pp. 4671–4680. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4671–4680 Mots-clés : Alumina Terpenic diolefins Epoxidation Water Résumé : Alumina is a heterogeneous catalyst for the regioselective epoxidation of terpenic diolefins that deactivates in presence of water. The reactions can be carried out at high temperature, above the boiling point of the solvent, increasing the pressure to maintain the reaction mixture in the liquid phase, yielding conversions between 41% and 96% and selectivities between 19% and 75% to monoepoxides with a significant decrease of reaction times. Deactivated alumina was analyzed, and an effective regeneration method was proposed. Furthermore, to improve the monoepoxide productivity, the effects of temperature, pressure, stirring rate, water concentration, alumina loading, and reactive concentrations were studied. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801763e

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Assessment of the production of oligomeric compounds from sugar beet pulp / Martina Martinez in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4681–4687 Titre : Assessment of the production of oligomeric compounds from sugar beet pulp Type de document : texte imprimé Auteurs : Martina Martinez, Auteur ; Beatriz Gullón, Auteur ; Henk A. Schols, Auteur Année de publication : 2009 Article en page(s) : pp. 4681–4687 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Sugar beet pulp Oligogalacturonides Arabinooligosaccharides Résumé : In order to obtain pectin-derived oligosaccharides (mainly arabinooligosaccharides and oligogalacturonides), samples of sugar beet pulp (SBP) were subjected to hydrothermal processing under nonisothermal conditions. Experiments carried out to reach temperatures in the range 160−175 °C (corresponding to values of the severity factor R0 in the range 287−835 min) led to comparatively high concentrations of both oligogalacturonides and arabinooligosaccharides. When SBP was treated to achieve a maximum temperature of 160 °C (R0 = 287 min) or 163 °C (R0 = 357 min), the overall amount of oligomers present in the reaction liquors recovered by pressing accounted for 31.2 and 29.9 g/100 g of oven-dried SBP, respectively, with a limited amount of nonvolatile impurities (about 0.15 g/g of oven-dried matter) and a mass ratio of arabinooligosaccharides/oligogalacturonides of about 1:1. Spent solids were washed with water, and the washing liquors were assayed for oligomers. Recovery of washing liquors would increase the overall yield process by 10%, to reach near 33 g/100 g of oven-dried SBP. Washed spent solids (with increased cellulose content) were obtained as a process byproduct. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8017753 [article] Assessment of the production of oligomeric compounds from sugar beet pulp [texte imprimé] / Martina Martinez, Auteur ; Beatriz Gullón, Auteur ; Henk A. Schols, Auteur . - 2009 . - pp. 4681–4687. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4681–4687 Mots-clés : Sugar beet pulp Oligogalacturonides Arabinooligosaccharides Résumé : In order to obtain pectin-derived oligosaccharides (mainly arabinooligosaccharides and oligogalacturonides), samples of sugar beet pulp (SBP) were subjected to hydrothermal processing under nonisothermal conditions. Experiments carried out to reach temperatures in the range 160−175 °C (corresponding to values of the severity factor R0 in the range 287−835 min) led to comparatively high concentrations of both oligogalacturonides and arabinooligosaccharides. When SBP was treated to achieve a maximum temperature of 160 °C (R0 = 287 min) or 163 °C (R0 = 357 min), the overall amount of oligomers present in the reaction liquors recovered by pressing accounted for 31.2 and 29.9 g/100 g of oven-dried SBP, respectively, with a limited amount of nonvolatile impurities (about 0.15 g/g of oven-dried matter) and a mass ratio of arabinooligosaccharides/oligogalacturonides of about 1:1. Spent solids were washed with water, and the washing liquors were assayed for oligomers. Recovery of washing liquors would increase the overall yield process by 10%, to reach near 33 g/100 g of oven-dried SBP. Washed spent solids (with increased cellulose content) were obtained as a process byproduct. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8017753

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Efficient cadmium(II) removal from aqueous solution using microwave synthesized guar gum-graft-poly(ethylacrylate) / Vandana Singh in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4688–4696 Titre : Efficient cadmium(II) removal from aqueous solution using microwave synthesized guar gum-graft-poly(ethylacrylate) Type de document : texte imprimé Auteurs : Vandana Singh, Auteur ; Ajit Kumar Sharma, Auteur ; Sadhana Maurya, Auteur Année de publication : 2009 Article en page(s) : pp. 4688–4696 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ethylacrylate Guar gum Cadmium concentration Résumé : Microwave induced emulsion copolymerization of ethylacrylate and guar gum resulted in copolymer samples of different % grafting (%G) by changing ethylacrylate and guar gum concentrations at fixed microwave power (100%) and exposure time (15 s). The synthesis was done in the absence of any redox initiator/catalyst, and the adsorption behavior of the copolymer (295%G) was investigated by performing both the kinetics and equilibrium studies in batch conditions. Several experimental parameters such as contact time, initial cadmium concentration, temperature, adsorbent dose, electrolyte amount, and pH of the solution were varied to optimize the adsorption conditions. The most favorable pH for the adsorption was pH 9, and at this pH the adsorption data were modeled using Langmuir and Freundlich isotherms. The data fitted satisfactorily to both the isotherms, indicating that the real heterogeneous nature of the surface sites involved in the metal uptake and overall sorption of Cd(II) on the adsorbent was complex and involved more than one mechanism. On the basis of the Langmuir model, Q0 was calculated to be 714.28 mg/g for microwave synthesized copolymer (mwGG-g-PEA) in comparison to 270.27 for conventionally synthesized copolymer (cvGG-g-PEA), revealing the advantage of using microwaves in the adsorbent synthesis. The sorption by mwGG-g-PEA followed pseudo-second-order kinetics where a linear plot of t/(qt) versus t was obtained, the correlation coefficient (R2) and rate constant at 100 mg/L Cd(II) being 0.9978 and 4.6 × 10−4 g/mg/min, respectively. The adsorbent exhibited high reusability and could be successfully recycled for nine cycles where in the ninth cycle 38% adsorption was feasible. To understand the role of PEA grafts (in the copolymer) in the adsorption process, different %G samples were evaluated as adsorbent under optimized conditions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801416z [article] Efficient cadmium(II) removal from aqueous solution using microwave synthesized guar gum-graft-poly(ethylacrylate) [texte imprimé] / Vandana Singh, Auteur ; Ajit Kumar Sharma, Auteur ; Sadhana Maurya, Auteur . - 2009 . - pp. 4688–4696. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4688–4696 Mots-clés : Ethylacrylate Guar gum Cadmium concentration Résumé : Microwave induced emulsion copolymerization of ethylacrylate and guar gum resulted in copolymer samples of different % grafting (%G) by changing ethylacrylate and guar gum concentrations at fixed microwave power (100%) and exposure time (15 s). The synthesis was done in the absence of any redox initiator/catalyst, and the adsorption behavior of the copolymer (295%G) was investigated by performing both the kinetics and equilibrium studies in batch conditions. Several experimental parameters such as contact time, initial cadmium concentration, temperature, adsorbent dose, electrolyte amount, and pH of the solution were varied to optimize the adsorption conditions. The most favorable pH for the adsorption was pH 9, and at this pH the adsorption data were modeled using Langmuir and Freundlich isotherms. The data fitted satisfactorily to both the isotherms, indicating that the real heterogeneous nature of the surface sites involved in the metal uptake and overall sorption of Cd(II) on the adsorbent was complex and involved more than one mechanism. On the basis of the Langmuir model, Q0 was calculated to be 714.28 mg/g for microwave synthesized copolymer (mwGG-g-PEA) in comparison to 270.27 for conventionally synthesized copolymer (cvGG-g-PEA), revealing the advantage of using microwaves in the adsorbent synthesis. The sorption by mwGG-g-PEA followed pseudo-second-order kinetics where a linear plot of t/(qt) versus t was obtained, the correlation coefficient (R2) and rate constant at 100 mg/L Cd(II) being 0.9978 and 4.6 × 10−4 g/mg/min, respectively. The adsorbent exhibited high reusability and could be successfully recycled for nine cycles where in the ninth cycle 38% adsorption was feasible. To understand the role of PEA grafts (in the copolymer) in the adsorption process, different %G samples were evaluated as adsorbent under optimized conditions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801416z

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Titania-acrylic coil reactor for photocatalytic water purification and sterilization / Luke H. Loetscher in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4697–4702 Titre : Titania-acrylic coil reactor for photocatalytic water purification and sterilization Type de document : texte imprimé Auteurs : Luke H. Loetscher, Auteur ; Jonathan M. Carey, Auteur ; Stephanie L. Skiles, Auteur Année de publication : 2009 Article en page(s) : pp. 4697–4702 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Titania−  acrylic reactor CoilCompact fluorescent blacklight Ultraviolet light emitting diodes Résumé : A titania−acrylic composite reactor was constructed with a coil geometry. The presence of multiple titania layers within the reactor increases the titania surface area while making maximum use of the illumination provided. Both compact fluorescent blacklight (CFL) and ultraviolet light emitting diodes (LEDs) were used as illumination sources. An external pump was used to recirculate 650−800 mL of water containing organic, metallic, or bacterial contamination through the coil reactor. Complete purification of the water was achieved within 300 min with 10 ppm methylene blue, 10 ppm methyl orange, 20 ppm Pb2+, and 2200 colony forming units per milliliter (CFU/mL) of E. coli respectively using the CFL source. The effectiveness, low cost, durability, ruggedness, and energy efficiency of this reactor are advantageous for both portable and fixed-base applications. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801916v [article] Titania-acrylic coil reactor for photocatalytic water purification and sterilization [texte imprimé] / Luke H. Loetscher, Auteur ; Jonathan M. Carey, Auteur ; Stephanie L. Skiles, Auteur . - 2009 . - pp. 4697–4702. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4697–4702 Mots-clés : Titania−  acrylic reactor CoilCompact fluorescent blacklight Ultraviolet light emitting diodes Résumé : A titania−acrylic composite reactor was constructed with a coil geometry. The presence of multiple titania layers within the reactor increases the titania surface area while making maximum use of the illumination provided. Both compact fluorescent blacklight (CFL) and ultraviolet light emitting diodes (LEDs) were used as illumination sources. An external pump was used to recirculate 650−800 mL of water containing organic, metallic, or bacterial contamination through the coil reactor. Complete purification of the water was achieved within 300 min with 10 ppm methylene blue, 10 ppm methyl orange, 20 ppm Pb2+, and 2200 colony forming units per milliliter (CFU/mL) of E. coli respectively using the CFL source. The effectiveness, low cost, durability, ruggedness, and energy efficiency of this reactor are advantageous for both portable and fixed-base applications. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801916v

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Inhibition effect of surfactants on CO2 enclathration with cyclopentane in an unstirred batch reactor / Junshe Zhang in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4703–4709 Titre : Inhibition effect of surfactants on CO2 enclathration with cyclopentane in an unstirred batch reactor Type de document : texte imprimé Auteurs : Junshe Zhang, Auteur ; Jae W. Lee, Auteur Année de publication : 2009 Article en page(s) : pp. 4703–4709 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Sodium dodecyl sulfate Cetyl trimethylammonium bromide Fatty alcohol EO/PO CO2 absorption Résumé : The effect of sodium dodecyl sulfate (SDS), cetyl trimethylammonium bromide (CTAB), and fatty alcohol EO/PO derivative (LS54) on unsteady-state CO2 absorption in the metastable region of CO2 hydrates and CO2 enclathration with cyclopentane (CP) was investigated in an unstirred batch reactor. These surfactants have no measurable effect on the mass transfer of CO2 across the gas−liquid interface into water. However, they retard CO2 enclathration, and this inhibition effect becomes significant at 200 ppm of SDS and 100 ppm of LS54 or CTAB. A layer of clathrate hydrates is visually observed if charging CO2 and CP sequentially. Even though this layer cannot be macroscopically detected when swapping the order of CO2 and CP charge, the existence of this layer can be inferred from the unchanged pressure profile. This layer prevents CO2 from contacting with water and thus delays CO2 enclathration. The habit of clathrate hydrates growing along the reactor wall without agitation is discussed based on the magnitude of temperature spikes at the initial stage of the enclathration. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8019328 [article] Inhibition effect of surfactants on CO2 enclathration with cyclopentane in an unstirred batch reactor [texte imprimé] / Junshe Zhang, Auteur ; Jae W. Lee, Auteur . - 2009 . - pp. 4703–4709. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4703–4709 Mots-clés : Sodium dodecyl sulfate Cetyl trimethylammonium bromide Fatty alcohol EO/PO CO2 absorption Résumé : The effect of sodium dodecyl sulfate (SDS), cetyl trimethylammonium bromide (CTAB), and fatty alcohol EO/PO derivative (LS54) on unsteady-state CO2 absorption in the metastable region of CO2 hydrates and CO2 enclathration with cyclopentane (CP) was investigated in an unstirred batch reactor. These surfactants have no measurable effect on the mass transfer of CO2 across the gas−liquid interface into water. However, they retard CO2 enclathration, and this inhibition effect becomes significant at 200 ppm of SDS and 100 ppm of LS54 or CTAB. A layer of clathrate hydrates is visually observed if charging CO2 and CP sequentially. Even though this layer cannot be macroscopically detected when swapping the order of CO2 and CP charge, the existence of this layer can be inferred from the unchanged pressure profile. This layer prevents CO2 from contacting with water and thus delays CO2 enclathration. The habit of clathrate hydrates growing along the reactor wall without agitation is discussed based on the magnitude of temperature spikes at the initial stage of the enclathration. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8019328

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Feasibility of reactive distillation for Fischer-Tropsch synthesis. 2 / Seethamraju Srinivas in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4710–4718 Titre : Feasibility of reactive distillation for Fischer-Tropsch synthesis. 2 Type de document : texte imprimé Auteurs : Seethamraju Srinivas, Auteur ; Ranjan K. Malik, Auteur ; Sanjay M. Mahajani, Auteur Année de publication : 2009 Article en page(s) : pp. 4710–4718 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Transportation fuels Fischer-Tropsch Synthesis technology Reactive distillation Résumé : The search for alternative sources of transportation fuels and energy security have revived an interest in the Fischer−Tropsch Synthesis (FTS) technology. Over the years, the main driver in FT reactor development has moved from the exothermic heat removal to the product distribution and selectivity. Reactive distillation (RD), a proven reactive separation method that can enhance yields and improve product selectivity in multiple reactant/product systems, was shown to be feasible for FTS in our earlier paper using a simplified kinetics [Srinivas, et al. Feasibility of Reactive distillation for Fischer−Tropsch Synthesis. Ind. Eng. Chem. Res. 2008, 48, 889−899]. This paper looks at the feasibility using a detailed kinetics incorporating olefin readsorption. In-built thermodynamic procedures of Aspen Plus, along with a detailed kinetic model that predicts product distribution, were used in performing the simulations. Some insight is given on the thermodynamics and kinetics used in performing the simulations. Conversion, yield, olefin-to-paraffin ratio, and product distribution are the parameters used for comparison among the different reactor types. Simulation results of the conventional reactors are compared with RD and it is seen that the performance of RD is at par or better than the conventional reactors. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801887m [article] Feasibility of reactive distillation for Fischer-Tropsch synthesis. 2 [texte imprimé] / Seethamraju Srinivas, Auteur ; Ranjan K. Malik, Auteur ; Sanjay M. Mahajani, Auteur . - 2009 . - pp. 4710–4718. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4710–4718 Mots-clés : Transportation fuels Fischer-Tropsch Synthesis technology Reactive distillation Résumé : The search for alternative sources of transportation fuels and energy security have revived an interest in the Fischer−Tropsch Synthesis (FTS) technology. Over the years, the main driver in FT reactor development has moved from the exothermic heat removal to the product distribution and selectivity. Reactive distillation (RD), a proven reactive separation method that can enhance yields and improve product selectivity in multiple reactant/product systems, was shown to be feasible for FTS in our earlier paper using a simplified kinetics [Srinivas, et al. Feasibility of Reactive distillation for Fischer−Tropsch Synthesis. Ind. Eng. Chem. Res. 2008, 48, 889−899]. This paper looks at the feasibility using a detailed kinetics incorporating olefin readsorption. In-built thermodynamic procedures of Aspen Plus, along with a detailed kinetic model that predicts product distribution, were used in performing the simulations. Some insight is given on the thermodynamics and kinetics used in performing the simulations. Conversion, yield, olefin-to-paraffin ratio, and product distribution are the parameters used for comparison among the different reactor types. Simulation results of the conventional reactors are compared with RD and it is seen that the performance of RD is at par or better than the conventional reactors. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801887m

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Feasibility of reactive distillation for Fischer-Tropsch synthesis. 3. / Seethamraju Srinivas in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4719–4730 Titre : Feasibility of reactive distillation for Fischer-Tropsch synthesis. 3. Type de document : texte imprimé Auteurs : Seethamraju Srinivas, Auteur ; Ranjan K. Malik, Auteur ; Sanjay M. Mahajani, Auteur Année de publication : 2009 Article en page(s) : pp. 4719–4730 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Reactive distillation Multiple reactant/product systems Fischer−  Tropsch Synthesis Résumé : Reactive distillation (RD), a proven reactive separation method that can enhance yields and improve product selectivity in multiple reactant/product systems, was shown to be feasible for FTS in our earlier papers using a simplified kinetics [Srinivas et al. Feasibility of Reactive Distillation for Fischer−Tropsch Synthesis. Ind. Eng. Chem. Res. 2008, 48, 889−899; DOI 10.1021/ie071094p] as well as a detailed kinetics [Srinivas et al. Feasibility of Reactive Distillation for Fischer−Tropsch Synthesis. 2. Ind. Eng. Chem. Res. 2009; DOI 10.1021/ie801887m]. In-built thermodynamic procedures of Aspen Plus, along with a detailed kinetic model that predicts product distribution, were used in performing the simulations. In this paper, we present detailed parametric studies like effect of reflux ratio, H2/CO feed ratio, number of nonreactive stages, etc. Conversion, yield, olefin-to-paraffin ratio and product distribution are the parameters used for comparison among the different cases studied. Within RD mode for FTS, some of the alternate column configurations like those with a side-heat removal and a side-draw, a hybrid column with reactive and nonreactive stages, are also explored and investigated. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801888v [article] Feasibility of reactive distillation for Fischer-Tropsch synthesis. 3. [texte imprimé] / Seethamraju Srinivas, Auteur ; Ranjan K. Malik, Auteur ; Sanjay M. Mahajani, Auteur . - 2009 . - pp. 4719–4730. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4719–4730 Mots-clés : Reactive distillation Multiple reactant/product systems Fischer−  Tropsch Synthesis Résumé : Reactive distillation (RD), a proven reactive separation method that can enhance yields and improve product selectivity in multiple reactant/product systems, was shown to be feasible for FTS in our earlier papers using a simplified kinetics [Srinivas et al. Feasibility of Reactive Distillation for Fischer−Tropsch Synthesis. Ind. Eng. Chem. Res. 2008, 48, 889−899; DOI 10.1021/ie071094p] as well as a detailed kinetics [Srinivas et al. Feasibility of Reactive Distillation for Fischer−Tropsch Synthesis. 2. Ind. Eng. Chem. Res. 2009; DOI 10.1021/ie801887m]. In-built thermodynamic procedures of Aspen Plus, along with a detailed kinetic model that predicts product distribution, were used in performing the simulations. In this paper, we present detailed parametric studies like effect of reflux ratio, H2/CO feed ratio, number of nonreactive stages, etc. Conversion, yield, olefin-to-paraffin ratio and product distribution are the parameters used for comparison among the different cases studied. Within RD mode for FTS, some of the alternate column configurations like those with a side-heat removal and a side-draw, a hybrid column with reactive and nonreactive stages, are also explored and investigated. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801888v

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Hydrothermal conversion of biomass: I, glucose conversion in hot compressed water / D. Knezevic in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4731–4743 Titre : Hydrothermal conversion of biomass: I, glucose conversion in hot compressed water Type de document : texte imprimé Auteurs : D. Knezevic, Auteur ; W. P. M. van Swaaij, Auteur ; S. R. A. Kersten, Auteur Année de publication : 2009 Article en page(s) : pp. 4731–4743 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hydrothermal conversion Biomass Glucose Résumé : In this paper, hydrothermal conversion of biomass is investigated. Part I deals with glucose and part II focuses on woody biomass and pyrolysis oil. Hydrothermal conversion of glucose (250−350 °C) has been studied in batch quartz capillary reactors. Kinetics of the overall glucose decomposition was determined and was in agreement with the majority of literature data. Attention was paid to the initial glucose decomposition: primary glucose decay products were identified from literature and used in experiments. It was found that all primary decay components of glucose, with the exception of formaldehyde, produce a kind of char (acetone insoluble product). Characteristic gas (primarily CO2) formation reactions are discussed on the basis of separate tests with primary and other known initial glucose degradation products. Complete mass and elemental balances were obtained for two different temperatures, 300 and 350 °C, and various residence times from 10 s to 10 days. It was clearly observed that the product formation as a function of residence time occurs in two distinctly different regimes. The first 5−10 min are characterized by fast changes, whereas after the initial 10 min the changes occur at a much lower rate. It was found that water production, which occurred predominantly in the first 5 min of residence time, was constant (3 mol/mol glucose) and unaffected by temperature or glucose concentration. The yield of the oil product, called here water−acetone soluble (WSS) yield exhibited a maximum at ca. 5 min residence time. After 5 min it was reduced in favor of gas and char, called here water−acetone insoluble (WSIS). However, a certain quantity of WSS is stable even after 10 days residence time. The elemental composition of WSS and WSIS was found to be very similar, which indicates that they are essentially the same product. The highest molecular weight fraction of this product does not dissolve in acetone, whereas the lower molecular weight part does. Compositions of gas, WSS, and WSIS were used as a basis for estimation of the overall reaction enthalpy, which was calculated to be ΔHr = −1.5 ± 0.5 MJ/kg. It was found that higher glucose concentrations resulted in more WSIS and less WSS, whereas the gas and water yield did not change. All findings were incorporated into a lumped engineering reaction path and kinetic model of glucose hydrothermal decomposition. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801387v [article] Hydrothermal conversion of biomass: I, glucose conversion in hot compressed water [texte imprimé] / D. Knezevic, Auteur ; W. P. M. van Swaaij, Auteur ; S. R. A. Kersten, Auteur . - 2009 . - pp. 4731–4743. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4731–4743 Mots-clés : Hydrothermal conversion Biomass Glucose Résumé : In this paper, hydrothermal conversion of biomass is investigated. Part I deals with glucose and part II focuses on woody biomass and pyrolysis oil. Hydrothermal conversion of glucose (250−350 °C) has been studied in batch quartz capillary reactors. Kinetics of the overall glucose decomposition was determined and was in agreement with the majority of literature data. Attention was paid to the initial glucose decomposition: primary glucose decay products were identified from literature and used in experiments. It was found that all primary decay components of glucose, with the exception of formaldehyde, produce a kind of char (acetone insoluble product). Characteristic gas (primarily CO2) formation reactions are discussed on the basis of separate tests with primary and other known initial glucose degradation products. Complete mass and elemental balances were obtained for two different temperatures, 300 and 350 °C, and various residence times from 10 s to 10 days. It was clearly observed that the product formation as a function of residence time occurs in two distinctly different regimes. The first 5−10 min are characterized by fast changes, whereas after the initial 10 min the changes occur at a much lower rate. It was found that water production, which occurred predominantly in the first 5 min of residence time, was constant (3 mol/mol glucose) and unaffected by temperature or glucose concentration. The yield of the oil product, called here water−acetone soluble (WSS) yield exhibited a maximum at ca. 5 min residence time. After 5 min it was reduced in favor of gas and char, called here water−acetone insoluble (WSIS). However, a certain quantity of WSS is stable even after 10 days residence time. The elemental composition of WSS and WSIS was found to be very similar, which indicates that they are essentially the same product. The highest molecular weight fraction of this product does not dissolve in acetone, whereas the lower molecular weight part does. Compositions of gas, WSS, and WSIS were used as a basis for estimation of the overall reaction enthalpy, which was calculated to be ΔHr = −1.5 ± 0.5 MJ/kg. It was found that higher glucose concentrations resulted in more WSIS and less WSS, whereas the gas and water yield did not change. All findings were incorporated into a lumped engineering reaction path and kinetic model of glucose hydrothermal decomposition. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801387v

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Fast pyrolysis of biomass in a fluidized bed reactor / Elly Hoekstra in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4744–4756 Titre : Fast pyrolysis of biomass in a fluidized bed reactor : in situ filtering of the vapors Type de document : texte imprimé Auteurs : Elly Hoekstra, Auteur ; Kees J. A. Hogendoorn, Auteur ; Xiaoquan Wang, Auteur Année de publication : 2009 Article en page(s) : pp. 4744–4756 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hot pyrolysis vapors Fluidized bed reactor Résumé : A system to remove in situ char/ash from hot pyrolysis vapors has been developed and tested at the University of Twente. The system consists of a continuous fluidized bed reactor (0.7 kg/h) with immersed filters (wire mesh, pore size 5 μm) for extracting pyrolysis vapors. Integration of the filter system in the fluidized bed should overcome operational problems related to the increase in pressure drop across the filter in time and a decrease in oil yield as typically observed in downstream pyrolysis vapor filtration and lead to process intensification. In this study the effect of in situ hot pyrolysis vapor filtration has been studied with respect to process stability, product yields, and product quality. Oil obtained via a more conventional cyclone system placed in parallel to the filter system served as reference for the quality and yields of the filtered oil. Good process stability concerning temperature and pressure drop across the hot gas vapor filter was achieved during a 2 h run, even when using a reused filter. Particles (char/sand) were retained inside the filter pores located at the outside surface of the filter, while the inside of the filter remained clean apart from some deposits formed on the metal wire and small 1 μm particles which slipped through the filter. Mass balance closures higher than 94 wt % were obtained. Comparable yields (cyclone + filtered oil) were obtained as in the experiments carried out with only the cyclones. The filtered oil contained significantly less solids, alkali metals, and ash compared to cyclone oil. For the alkali metals, only a considerable amount of potassium (K) was still present in filtered pyrolysis oil, which most likely entered the filtered oil via the vapor phase. There were no significant differences in the elemental composition of the oil produced via the filter line and cyclone line. The molecular weight of the filtered oil obtained with nondried feed was always marginally lower compared to the cyclone oil. Results of the aging tests show that the reactivity of pyrolysis oil can already originate from the highly reactive components in pyrolysis oil itself and does not need the presence of char/ash. To show the intrinsically high reactivity of solids-free pyrolysis oil vapors, an external filter section (1 μm pore size) was placed additionally and in series with the filter inside the fluidized bed. The results show that char is formed from the reactive pyrolysis vapors. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8017274 [article] Fast pyrolysis of biomass in a fluidized bed reactor : in situ filtering of the vapors [texte imprimé] / Elly Hoekstra, Auteur ; Kees J. A. Hogendoorn, Auteur ; Xiaoquan Wang, Auteur . - 2009 . - pp. 4744–4756. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4744–4756 Mots-clés : Hot pyrolysis vapors Fluidized bed reactor Résumé : A system to remove in situ char/ash from hot pyrolysis vapors has been developed and tested at the University of Twente. The system consists of a continuous fluidized bed reactor (0.7 kg/h) with immersed filters (wire mesh, pore size 5 μm) for extracting pyrolysis vapors. Integration of the filter system in the fluidized bed should overcome operational problems related to the increase in pressure drop across the filter in time and a decrease in oil yield as typically observed in downstream pyrolysis vapor filtration and lead to process intensification. In this study the effect of in situ hot pyrolysis vapor filtration has been studied with respect to process stability, product yields, and product quality. Oil obtained via a more conventional cyclone system placed in parallel to the filter system served as reference for the quality and yields of the filtered oil. Good process stability concerning temperature and pressure drop across the hot gas vapor filter was achieved during a 2 h run, even when using a reused filter. Particles (char/sand) were retained inside the filter pores located at the outside surface of the filter, while the inside of the filter remained clean apart from some deposits formed on the metal wire and small 1 μm particles which slipped through the filter. Mass balance closures higher than 94 wt % were obtained. Comparable yields (cyclone + filtered oil) were obtained as in the experiments carried out with only the cyclones. The filtered oil contained significantly less solids, alkali metals, and ash compared to cyclone oil. For the alkali metals, only a considerable amount of potassium (K) was still present in filtered pyrolysis oil, which most likely entered the filtered oil via the vapor phase. There were no significant differences in the elemental composition of the oil produced via the filter line and cyclone line. The molecular weight of the filtered oil obtained with nondried feed was always marginally lower compared to the cyclone oil. Results of the aging tests show that the reactivity of pyrolysis oil can already originate from the highly reactive components in pyrolysis oil itself and does not need the presence of char/ash. To show the intrinsically high reactivity of solids-free pyrolysis oil vapors, an external filter section (1 μm pore size) was placed additionally and in series with the filter inside the fluidized bed. The results show that char is formed from the reactive pyrolysis vapors. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8017274

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Hydrolysis of triglycerides using solid acid catalysts / Kanokwan Ngaosuwan in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4757–4767 Titre : Hydrolysis of triglycerides using solid acid catalysts Type de document : texte imprimé Auteurs : Kanokwan Ngaosuwan, Auteur ; Edgar Lotero, Auteur ; Kaewta Suwannakarn, Auteur Année de publication : 2009 Article en page(s) : pp. 4757–4767 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Triglycerides Noncatalytic hydrolysis Solid acid Résumé : The commercial production of free fatty acids (FFAs) is carried out through the noncatalytic hydrolysis of triglycerides (TGs) using great amounts of superheated steam in large reactors made of expensive corrosion-resistant materials, making the process energy intensive and costly. In this study, the feasibility of a continuous reaction system using a solid acid for the hydrolysis of TGs at atmospheric pressure has been investigated. This research was to explore the viability of heterogeneous catalyzed hydrolysis of oils and fats for the synthesis of FFAs, a platform reaction of the oleochemical industry and a possible reaction in a novel two-step (hydrolysis−esterification) biodiesel synthesis process using low-cost feedstocks containing >5−15% FFAs. Tricaprylin (TCp) was used as a model compound representing TGs in order to obtain reliable intrinsic kinetics. Using tungstated zirconia (WZ) and the solid acid composite SAC-13 (Nafion resin nanoparticles supported on mesoporous silica) as catalysts, the hydrolysis of TCp was carried out at 110−150 °C in a semibatch reactor with continuous addition of water at low flow rates capable of achieving 100% selectivity of the carboxylic acid side chains on the triglyceride to HCp. The characteristics of the catalysts played an important role in reaction selectivity, apparent activation energy, and deactivation. Catalyst recycling experiments showed continuous activity loss for both catalysts. Characterization of the used catalysts indicated that deactivation was likely caused by the strong adsorption of bulky reaction intermediates on the catalytic acid sites, blocking reactant accessibility. For WZ, recalcination in air was an effective regeneration method resulting in the recovery of 100% of its original activity. Regeneration by calcination was not possible for SAC-13 due to its temperature sensitivity. Methanol washing of used WZ and SAC-13 catalysts only partially regenerated catalyst activity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8013988 [article] Hydrolysis of triglycerides using solid acid catalysts [texte imprimé] / Kanokwan Ngaosuwan, Auteur ; Edgar Lotero, Auteur ; Kaewta Suwannakarn, Auteur . - 2009 . - pp. 4757–4767. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4757–4767 Mots-clés : Triglycerides Noncatalytic hydrolysis Solid acid Résumé : The commercial production of free fatty acids (FFAs) is carried out through the noncatalytic hydrolysis of triglycerides (TGs) using great amounts of superheated steam in large reactors made of expensive corrosion-resistant materials, making the process energy intensive and costly. In this study, the feasibility of a continuous reaction system using a solid acid for the hydrolysis of TGs at atmospheric pressure has been investigated. This research was to explore the viability of heterogeneous catalyzed hydrolysis of oils and fats for the synthesis of FFAs, a platform reaction of the oleochemical industry and a possible reaction in a novel two-step (hydrolysis−esterification) biodiesel synthesis process using low-cost feedstocks containing >5−15% FFAs. Tricaprylin (TCp) was used as a model compound representing TGs in order to obtain reliable intrinsic kinetics. Using tungstated zirconia (WZ) and the solid acid composite SAC-13 (Nafion resin nanoparticles supported on mesoporous silica) as catalysts, the hydrolysis of TCp was carried out at 110−150 °C in a semibatch reactor with continuous addition of water at low flow rates capable of achieving 100% selectivity of the carboxylic acid side chains on the triglyceride to HCp. The characteristics of the catalysts played an important role in reaction selectivity, apparent activation energy, and deactivation. Catalyst recycling experiments showed continuous activity loss for both catalysts. Characterization of the used catalysts indicated that deactivation was likely caused by the strong adsorption of bulky reaction intermediates on the catalytic acid sites, blocking reactant accessibility. For WZ, recalcination in air was an effective regeneration method resulting in the recovery of 100% of its original activity. Regeneration by calcination was not possible for SAC-13 due to its temperature sensitivity. Methanol washing of used WZ and SAC-13 catalysts only partially regenerated catalyst activity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8013988

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Bayesian framework for building kinetic models of catalytic systems / Shuo-Huan Hsu in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4768–4790 Titre : Bayesian framework for building kinetic models of catalytic systems Type de document : texte imprimé Auteurs : Shuo-Huan Hsu, Auteur ; Stephen D. Stamatis, Auteur ; James M. Caruthers, Auteur Année de publication : 2009 Article en page(s) : pp. 4768–4790 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Catalytic systems Bayesian approach Monte Carlo based methods Résumé : Recent advances in statistical procedures, coupled with the availability of high performance computational resources and the large mass of data generated from high throughput screening, have enabled a new paradigm for building mathematical models of the kinetic behavior of catalytic reactions. A Bayesian approach is used to formulate the model building problem, estimate model parameters by Monte Carlo based methods, discriminate rival models, and design new experiments to improve the discrimination and fidelity of the parameter estimates. The methodology is illustrated with a typical, model building problem involving three proposed Langmuir−Hinshelwood rate expressions. The Bayesian approach gives improved discrimination of the three models and higher quality model parameters for the best model selected as compared to the traditional methods that employ linearized statistical tools. This paper describes the methodology and its capabilities in sufficient detail to allow kinetic model builders to evaluate and implement its improved model discrimination and parameter estimation features. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801651y [article] Bayesian framework for building kinetic models of catalytic systems [texte imprimé] / Shuo-Huan Hsu, Auteur ; Stephen D. Stamatis, Auteur ; James M. Caruthers, Auteur . - 2009 . - pp. 4768–4790. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4768–4790 Mots-clés : Catalytic systems Bayesian approach Monte Carlo based methods Résumé : Recent advances in statistical procedures, coupled with the availability of high performance computational resources and the large mass of data generated from high throughput screening, have enabled a new paradigm for building mathematical models of the kinetic behavior of catalytic reactions. A Bayesian approach is used to formulate the model building problem, estimate model parameters by Monte Carlo based methods, discriminate rival models, and design new experiments to improve the discrimination and fidelity of the parameter estimates. The methodology is illustrated with a typical, model building problem involving three proposed Langmuir−Hinshelwood rate expressions. The Bayesian approach gives improved discrimination of the three models and higher quality model parameters for the best model selected as compared to the traditional methods that employ linearized statistical tools. This paper describes the methodology and its capabilities in sufficient detail to allow kinetic model builders to evaluate and implement its improved model discrimination and parameter estimation features. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801651y

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Experimental and theoretical analysis of the alkali impregnation of eucalyptus wood / Maria C. Inalbon in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4791–4795 Titre : Experimental and theoretical analysis of the alkali impregnation of eucalyptus wood Type de document : texte imprimé Auteurs : Maria C. Inalbon, Auteur ; Miguel C. Mussati, Auteur ; Miguel A. Zanuttini, Auteur Année de publication : 2009 Article en page(s) : pp. 4791–4795 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Eucalyptus wood Impregnation Alkali concentration Dynamic diffusion coefficient Kinetics Résumé : Wood impregnation is crucial in any pulping process. The impregnation of chips of eucalyptus wood by a liquor of constant alkali concentration is here analyzed. A mass balance that considers kinetics of the main reactions and a dynamic diffusion coefficient is applied for the six chemical species analyzed. The diffusion rate is assumed dependent on temperature, alkali concentration, and the advance degree of reactions. The predicted concentration profiles are in acceptable agreement with the experimental results for hidroxyl and sodium ions, as well as for acetyl groups. For each set of impregnation conditions and chip thickness, characteristic impregnation times or impregnation levels can be predicted by the model. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801685a [article] Experimental and theoretical analysis of the alkali impregnation of eucalyptus wood [texte imprimé] / Maria C. Inalbon, Auteur ; Miguel C. Mussati, Auteur ; Miguel A. Zanuttini, Auteur . - 2009 . - pp. 4791–4795. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4791–4795 Mots-clés : Eucalyptus wood Impregnation Alkali concentration Dynamic diffusion coefficient Kinetics Résumé : Wood impregnation is crucial in any pulping process. The impregnation of chips of eucalyptus wood by a liquor of constant alkali concentration is here analyzed. A mass balance that considers kinetics of the main reactions and a dynamic diffusion coefficient is applied for the six chemical species analyzed. The diffusion rate is assumed dependent on temperature, alkali concentration, and the advance degree of reactions. The predicted concentration profiles are in acceptable agreement with the experimental results for hidroxyl and sodium ions, as well as for acetyl groups. For each set of impregnation conditions and chip thickness, characteristic impregnation times or impregnation levels can be predicted by the model. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801685a

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Wood fast pyrolysis / Olivier Authier in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4796–4809 Titre : Wood fast pyrolysis : comparison of lagrangian and eulerian modeling approaches with experimental measurements Type de document : texte imprimé Auteurs : Olivier Authier, Auteur ; Monique Ferrer, Auteur ; Guillain Mauviel, Auteur Année de publication : 2009 Article en page(s) : pp. 4796–4809 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Biomass fast pyrolysis Lagrangian modeling Eulerian Dual fluidized bed gasifier Résumé : The aim of the present paper is to validate Lagrangian and Eulerian modeling approaches of biomass fast pyrolysis from comparison with experimental measurements. Wood samples are submitted during measured times to a controlled and concentrated radiation delivered by an image furnace. The heat flux densities are close to those encountered when wood is surrounded by hot bed particles in a dual fluidized bed (DFB) gasifier. In the image furnace, the sample is placed inside a transparent quartz reactor fed by a cold carrier gas. The volatile matter (condensable vapors and gases) released by the solid is quenched inside the reactor. It is hence possible to selectively study primary pyrolysis phenomena occurring at the solid level. All the pyrolysis products (char, vapors, and gases) are recovered, and their masses are measured as a function of the flash time allowing the assessment of mass balances. The yield of vapors does not significantly depend on the available heat flux density, unlike the gases and char yields. The experimental results are compared to data derived from two different modeling approaches. Their basic assumptions are discussed from characteristic time values which reveal the controlling phenomena. Mass transfer limitations are neglected in comparison with heat transfer and chemical phenomena. The first type of pyrolysis model relies on an original Lagrangian approach where mathematical equations of heat and mass balances are written with the assumptions that wood and char form two distinct layers. In the second one, a classical Eulerian approach is considered: equations are directly written at the whole particle level. The results of the two models as well as the experimental data (sample mass losses and product yields) are in quite good agreement. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801854c [article] Wood fast pyrolysis : comparison of lagrangian and eulerian modeling approaches with experimental measurements [texte imprimé] / Olivier Authier, Auteur ; Monique Ferrer, Auteur ; Guillain Mauviel, Auteur . - 2009 . - pp. 4796–4809. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4796–4809 Mots-clés : Biomass fast pyrolysis Lagrangian modeling Eulerian Dual fluidized bed gasifier Résumé : The aim of the present paper is to validate Lagrangian and Eulerian modeling approaches of biomass fast pyrolysis from comparison with experimental measurements. Wood samples are submitted during measured times to a controlled and concentrated radiation delivered by an image furnace. The heat flux densities are close to those encountered when wood is surrounded by hot bed particles in a dual fluidized bed (DFB) gasifier. In the image furnace, the sample is placed inside a transparent quartz reactor fed by a cold carrier gas. The volatile matter (condensable vapors and gases) released by the solid is quenched inside the reactor. It is hence possible to selectively study primary pyrolysis phenomena occurring at the solid level. All the pyrolysis products (char, vapors, and gases) are recovered, and their masses are measured as a function of the flash time allowing the assessment of mass balances. The yield of vapors does not significantly depend on the available heat flux density, unlike the gases and char yields. The experimental results are compared to data derived from two different modeling approaches. Their basic assumptions are discussed from characteristic time values which reveal the controlling phenomena. Mass transfer limitations are neglected in comparison with heat transfer and chemical phenomena. The first type of pyrolysis model relies on an original Lagrangian approach where mathematical equations of heat and mass balances are written with the assumptions that wood and char form two distinct layers. In the second one, a classical Eulerian approach is considered: equations are directly written at the whole particle level. The results of the two models as well as the experimental data (sample mass losses and product yields) are in quite good agreement. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801854c

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Study of butyl methacrylate depropagation behavior using batch experiments in combination with modeling / Wei Wang in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4810–4816 Titre : Study of butyl methacrylate depropagation behavior using batch experiments in combination with modeling Type de document : texte imprimé Auteurs : Wei Wang, Auteur ; Robin A. Hutchinson, Auteur Année de publication : 2009 Article en page(s) : pp. 4810–4816 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Butyl methacrylate Polymerization Depropagation behavior Résumé : Batch polymerization experiments are combined with simulations to investigate the depropagation behavior of butyl methacrylate (BMA). Experiments carried out between 110 and 145 °C and polymer contents between 9 and 34 wt %, including experiments conducted with added polymer, indicate that equilibrium monomer concentration ([M]eq) varies not only with temperature but also with polymer content. An extended Predici model provides a good fit to the monomer concentration and polymer molecular weight profiles, with the simulated monomer profiles at 132 and 145 °C sensitive to small changes in the depropagation activation energy. Thus, these data provide a better estimate of depropagation kinetics than those measured by the pulsed-laser polymerization/size-exclusion chromatography method. The entire data set is well-represented by [M]eq (mol·L −1) = 1.76 × 106(1 − 0.778xwp) exp(−6240/T), in which xwp represents the weight fraction of polymer in the system. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900060x [article] Study of butyl methacrylate depropagation behavior using batch experiments in combination with modeling [texte imprimé] / Wei Wang, Auteur ; Robin A. Hutchinson, Auteur . - 2009 . - pp. 4810–4816. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4810–4816 Mots-clés : Butyl methacrylate Polymerization Depropagation behavior Résumé : Batch polymerization experiments are combined with simulations to investigate the depropagation behavior of butyl methacrylate (BMA). Experiments carried out between 110 and 145 °C and polymer contents between 9 and 34 wt %, including experiments conducted with added polymer, indicate that equilibrium monomer concentration ([M]eq) varies not only with temperature but also with polymer content. An extended Predici model provides a good fit to the monomer concentration and polymer molecular weight profiles, with the simulated monomer profiles at 132 and 145 °C sensitive to small changes in the depropagation activation energy. Thus, these data provide a better estimate of depropagation kinetics than those measured by the pulsed-laser polymerization/size-exclusion chromatography method. The entire data set is well-represented by [M]eq (mol·L −1) = 1.76 × 106(1 − 0.778xwp) exp(−6240/T), in which xwp represents the weight fraction of polymer in the system. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900060x

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Rheology, crystallization, and biodegradability of blends based on soy protein and chemically modified poly(butylene succinate) / Yi-Dong Li in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4817–4825 Titre : Rheology, crystallization, and biodegradability of blends based on soy protein and chemically modified poly(butylene succinate) Type de document : texte imprimé Auteurs : Yi-Dong Li, Auteur ; Jian-Bing Zeng, Auteur ; Wen-Da Li, Auteur Année de publication : 2009 Article en page(s) : pp. 4817–4825 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : PBS blends Soy protein Crystallization Biodegradability Rheology Résumé : In our previous study, we found that modification of poly(butylene succinate) (PBS) by introducing urethane and isocyanate groups is an effective method for improving the mechanical properties and water resistance of soy-protein-based bioplastics. This study presents the effects of the structure and content of PBS components on the rheology, crystallization, and biodegradability of soy protein/PBS blends. Tests using a Haake torque rheometer and a high-pressure capillary rheometer both indicated that chemically modified PBS with a relatively low molecular weight can improve the flowability of the blend. According to differential scanning calorimeter measurements, the crystallization ability of the PBS component in a blend with improved compatibility is enhanced markedly compared with that of the pure PBS, and the nonisothermal crystallization behavior could be described by the Jeziorny model. A combination of the weight losses of the samples with the characterization of the surface microstructure shows that both the structure and the content of PBS influence the biodegradation rate of the blend in a compost medium. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801718f [article] Rheology, crystallization, and biodegradability of blends based on soy protein and chemically modified poly(butylene succinate) [texte imprimé] / Yi-Dong Li, Auteur ; Jian-Bing Zeng, Auteur ; Wen-Da Li, Auteur . - 2009 . - pp. 4817–4825. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4817–4825 Mots-clés : PBS blends Soy protein Crystallization Biodegradability Rheology Résumé : In our previous study, we found that modification of poly(butylene succinate) (PBS) by introducing urethane and isocyanate groups is an effective method for improving the mechanical properties and water resistance of soy-protein-based bioplastics. This study presents the effects of the structure and content of PBS components on the rheology, crystallization, and biodegradability of soy protein/PBS blends. Tests using a Haake torque rheometer and a high-pressure capillary rheometer both indicated that chemically modified PBS with a relatively low molecular weight can improve the flowability of the blend. According to differential scanning calorimeter measurements, the crystallization ability of the PBS component in a blend with improved compatibility is enhanced markedly compared with that of the pure PBS, and the nonisothermal crystallization behavior could be described by the Jeziorny model. A combination of the weight losses of the samples with the characterization of the surface microstructure shows that both the structure and the content of PBS influence the biodegradation rate of the blend in a compost medium. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801718f

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Polymeric branched flocculant effect on the flocculation process of pulp suspensions in the papermaking industry / Angeles Blanco in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4826–4836 Titre : Polymeric branched flocculant effect on the flocculation process of pulp suspensions in the papermaking industry Type de document : texte imprimé Auteurs : Angeles Blanco, Auteur ; Elena Fuente, Auteur ; M. Concepcion Monte, Auteur Année de publication : 2009 Article en page(s) : pp. 4826–4836 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Cationic polyacrylamides Pulp suspensions Floc properties Focused beam reflectance measurement Résumé : This paper presents the effect of the structure of cationic polyacrylamides (CPAMs) on flocculation of pulp suspensions and floc properties. A focused beam reflectance measurement (FBRM) probe was used to monitor flocculation, deflocculation, and reflocculation processes in real time. To carry out the study, 1% elemental chlorine free (ECF) eucalyptus kraft pulp containing 20% ground calcium carbonate (GCC) was used. Results show that the effect of the CPAM structure depends on charge density and polymer dose. Floc size does not always decrease with branching degree, whereas floc stability and reflocculation ability increased when highly charged and branched CPAM was used. These findings indicate that the use of highly branched CPAMs with very high molecular weight is very promising as a retention aid method to improve the papermaking process. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8011837 [article] Polymeric branched flocculant effect on the flocculation process of pulp suspensions in the papermaking industry [texte imprimé] / Angeles Blanco, Auteur ; Elena Fuente, Auteur ; M. Concepcion Monte, Auteur . - 2009 . - pp. 4826–4836. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4826–4836 Mots-clés : Cationic polyacrylamides Pulp suspensions Floc properties Focused beam reflectance measurement Résumé : This paper presents the effect of the structure of cationic polyacrylamides (CPAMs) on flocculation of pulp suspensions and floc properties. A focused beam reflectance measurement (FBRM) probe was used to monitor flocculation, deflocculation, and reflocculation processes in real time. To carry out the study, 1% elemental chlorine free (ECF) eucalyptus kraft pulp containing 20% ground calcium carbonate (GCC) was used. Results show that the effect of the CPAM structure depends on charge density and polymer dose. Floc size does not always decrease with branching degree, whereas floc stability and reflocculation ability increased when highly charged and branched CPAM was used. These findings indicate that the use of highly branched CPAMs with very high molecular weight is very promising as a retention aid method to improve the papermaking process. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8011837

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A novel approach for the synthesis of zeolite Y / D. Karami in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4837–4843 Titre : A novel approach for the synthesis of zeolite Y Type de document : texte imprimé Auteurs : D. Karami, Auteur ; S. Rohani, Auteur Année de publication : 2009 Article en page(s) : pp. 4837–4843 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Zeolite Y X ray diffraction Résumé : In this study, a novel approach for the synthesis of zeolite Y is described. The effect of varying the starting silica source on the purity of zeolite Y was investigated, while all other reaction parameters were kept constant. The purity of zeolite was expressed in terms of percent crystallinity obtained from the powder XRD. The silica sources were all powders of varying types (except for silica sol). To study the influence of the varying silica sources on the purity of the resulting zeolite Y, the best gel composition and synthesis condition for one batch were chosen. The gel composition was 4Na2O:1Al2O3:6SiO2:200H2O. The aging temperature and duration of aging were chosen as room temperature and 120 h, respectively. The synthesis temperature and synthesis time were 100 °C and 48 h. The experiments were all conducted in sealed 30 mL Teflon bottles. The extent to which the pure zeolite Y was formed depended on the BET specific surface area of the silica sources (ranging from 150 to 300 m2/g) but not on the synthesis conditions. This novel method for zeolite Y preparation allows one to eliminate the vigorous agitation step required for the preparation of a homogeneous silica solution, thereby simplifying the synthesis of zeolite Y in one single vessel. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801338u [article] A novel approach for the synthesis of zeolite Y [texte imprimé] / D. Karami, Auteur ; S. Rohani, Auteur . - 2009 . - pp. 4837–4843. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4837–4843 Mots-clés : Zeolite Y X ray diffraction Résumé : In this study, a novel approach for the synthesis of zeolite Y is described. The effect of varying the starting silica source on the purity of zeolite Y was investigated, while all other reaction parameters were kept constant. The purity of zeolite was expressed in terms of percent crystallinity obtained from the powder XRD. The silica sources were all powders of varying types (except for silica sol). To study the influence of the varying silica sources on the purity of the resulting zeolite Y, the best gel composition and synthesis condition for one batch were chosen. The gel composition was 4Na2O:1Al2O3:6SiO2:200H2O. The aging temperature and duration of aging were chosen as room temperature and 120 h, respectively. The synthesis temperature and synthesis time were 100 °C and 48 h. The experiments were all conducted in sealed 30 mL Teflon bottles. The extent to which the pure zeolite Y was formed depended on the BET specific surface area of the silica sources (ranging from 150 to 300 m2/g) but not on the synthesis conditions. This novel method for zeolite Y preparation allows one to eliminate the vigorous agitation step required for the preparation of a homogeneous silica solution, thereby simplifying the synthesis of zeolite Y in one single vessel. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801338u

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Synthesis of monodisperse glycerol dimethacrylate-based microgel particles by precipitation polymerization / Berna Saraçoglu in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4844–4851 Titre : Synthesis of monodisperse glycerol dimethacrylate-based microgel particles by precipitation polymerization Type de document : texte imprimé Auteurs : Berna Saraçoglu, Auteur ; Erdal Uguzdogan, Auteur ; Çigdem Gölgelioglu, Auteur Année de publication : 2009 Article en page(s) : pp. 4844–4851 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Glycerol dimethacrylate Monodisperse microgel Polymerizations Résumé : A new, single-stage precipitation polymerization was proposed for the synthesis of monodisperse cross-linked glycerol dimethacrylate (GDMA)-based microgel particles carrying hydroxyl and carboxyl functionalities, from nanometer to micrometer size range. The synthesis of monodisperse microgel spheres in the size range of 30−1500 nm was possible by the proposed method. In the polymerizations, glycerol dimethacrylate was copolymerized with methacrylic acid (MAA) in the medium containing toluene and acetonitrile without using a stabilizing agent. The effects of polymerization conditions on the final monomer conversion, polymerization kinetics, and MAA distribution in the microgel particles were investigated. The hydrodynamic size, the size distribution characteristics, and the mass charge density of microgel particles were also determined. Highly monodisperse and spherical microgel particles were obtained particularly with low GDMA feed concentrations. A marked increase in the hydrodynamic size was observed with the decreasing polarity (i.e., increasing toluene concentration) in the continuous medium. The distribution of MAA in the particles and the effect of pH on the swelling behavior in the aqueous medium indicated that the microgel particles contained a swellable shell and a nonswellable core. Most of the MAA charged was buried within the core part of the microgel particles. The swelling of microgel was controlled by the ionization of the carboxyl groups located on the shell layer. The swellable character, the presence of functional groups for surface derivatization, and the similarity of microgel to a biocompatible structure, poly(hydroxyethyl methacrylate), make the new microgel a promising material for biomedical applications. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801572w [article] Synthesis of monodisperse glycerol dimethacrylate-based microgel particles by precipitation polymerization [texte imprimé] / Berna Saraçoglu, Auteur ; Erdal Uguzdogan, Auteur ; Çigdem Gölgelioglu, Auteur . - 2009 . - pp. 4844–4851. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4844–4851 Mots-clés : Glycerol dimethacrylate Monodisperse microgel Polymerizations Résumé : A new, single-stage precipitation polymerization was proposed for the synthesis of monodisperse cross-linked glycerol dimethacrylate (GDMA)-based microgel particles carrying hydroxyl and carboxyl functionalities, from nanometer to micrometer size range. The synthesis of monodisperse microgel spheres in the size range of 30−1500 nm was possible by the proposed method. In the polymerizations, glycerol dimethacrylate was copolymerized with methacrylic acid (MAA) in the medium containing toluene and acetonitrile without using a stabilizing agent. The effects of polymerization conditions on the final monomer conversion, polymerization kinetics, and MAA distribution in the microgel particles were investigated. The hydrodynamic size, the size distribution characteristics, and the mass charge density of microgel particles were also determined. Highly monodisperse and spherical microgel particles were obtained particularly with low GDMA feed concentrations. A marked increase in the hydrodynamic size was observed with the decreasing polarity (i.e., increasing toluene concentration) in the continuous medium. The distribution of MAA in the particles and the effect of pH on the swelling behavior in the aqueous medium indicated that the microgel particles contained a swellable shell and a nonswellable core. Most of the MAA charged was buried within the core part of the microgel particles. The swelling of microgel was controlled by the ionization of the carboxyl groups located on the shell layer. The swellable character, the presence of functional groups for surface derivatization, and the similarity of microgel to a biocompatible structure, poly(hydroxyethyl methacrylate), make the new microgel a promising material for biomedical applications. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801572w

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Effect of extraction solvent on the bioactivity of an herbal formulation / Kin N. Chan in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4852–4857 Titre : Effect of extraction solvent on the bioactivity of an herbal formulation Type de document : texte imprimé Auteurs : Kin N. Chan, Auteur ; Choi C. Lau, Auteur ; King L. Chow, Auteur Année de publication : 2009 Article en page(s) : pp. 4852–4857 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Zhikang Granules Extraction solvents Chrysophanol Résumé : Zhikang Granules (ZKG) is a traditional Chinese medicine prescription for the treatment of hyperlipidemia symptoms. In this study, the effect of extraction solvents—namely, acetone, ethanol, and water—on the recovery of a bioactive ingredient—namely, chrysophanol—and on the bioactivity of this herbal formulation was investigated. Although the solubility of chrysophanol is highest in acetone, the amount of chrysophanol extracted from Semen Cassiae is lowest in this solvent. Water was found to play an important role in the release of chrysophanol from Semen Cassiae. Two alternative ZKG processing methods are proposed based on the findings of bench-scale extraction tests. The resulting products were analyzed by both chemical analyses and biological assays. One of the products offered the same level of bioactivity while using only 10% of the original amount of Semen Cassiae. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8012538 [article] Effect of extraction solvent on the bioactivity of an herbal formulation [texte imprimé] / Kin N. Chan, Auteur ; Choi C. Lau, Auteur ; King L. Chow, Auteur . - 2009 . - pp. 4852–4857. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4852–4857 Mots-clés : Zhikang Granules Extraction solvents Chrysophanol Résumé : Zhikang Granules (ZKG) is a traditional Chinese medicine prescription for the treatment of hyperlipidemia symptoms. In this study, the effect of extraction solvents—namely, acetone, ethanol, and water—on the recovery of a bioactive ingredient—namely, chrysophanol—and on the bioactivity of this herbal formulation was investigated. Although the solubility of chrysophanol is highest in acetone, the amount of chrysophanol extracted from Semen Cassiae is lowest in this solvent. Water was found to play an important role in the release of chrysophanol from Semen Cassiae. Two alternative ZKG processing methods are proposed based on the findings of bench-scale extraction tests. The resulting products were analyzed by both chemical analyses and biological assays. One of the products offered the same level of bioactivity while using only 10% of the original amount of Semen Cassiae. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8012538

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Extractive distillation of acetone/methanol mixture using water as entrainer / Iván D. Gil in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4858–4865 Titre : Extractive distillation of acetone/methanol mixture using water as entrainer Type de document : texte imprimé Auteurs : Iván D. Gil, Auteur ; Diana C. Botía, Auteur ; Pablo Ortiz, Auteur Année de publication : 2009 Article en page(s) : pp. 4858–4865 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Acetone-methanol Extractive distillation Vapor−  liquid equilibrium UNIQUAC model Résumé : The acetone−methanol extractive distillation using water as an entrainer was simulated on Aspen Plus software package using rigorous methods. Calculation of the vapor−liquid equilibrium for the ternary system was done by the UNIQUAC model according to the experimental results obtained in a previous work. The effects of the solvent to feed molar ratio, reflux ratio, feed stage, feed solvent stage, and solvent feed temperature were studied to obtain the best design of the extractive distillation column with minimal energy requirements. The most appropriate configuration is 52 theoretical stages. The best binary mixture and entrainer feeding stages were obtained at 48 and 22 respectively with a solvent to feed molar and reflux ratio of 2.0 and 5.0, respectively. The simulation results show the effect of the main variables on the extractive distillation process. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801637h [article] Extractive distillation of acetone/methanol mixture using water as entrainer [texte imprimé] / Iván D. Gil, Auteur ; Diana C. Botía, Auteur ; Pablo Ortiz, Auteur . - 2009 . - pp. 4858–4865. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4858–4865 Mots-clés : Acetone-methanol Extractive distillation Vapor−  liquid equilibrium UNIQUAC model Résumé : The acetone−methanol extractive distillation using water as an entrainer was simulated on Aspen Plus software package using rigorous methods. Calculation of the vapor−liquid equilibrium for the ternary system was done by the UNIQUAC model according to the experimental results obtained in a previous work. The effects of the solvent to feed molar ratio, reflux ratio, feed stage, feed solvent stage, and solvent feed temperature were studied to obtain the best design of the extractive distillation column with minimal energy requirements. The most appropriate configuration is 52 theoretical stages. The best binary mixture and entrainer feeding stages were obtained at 48 and 22 respectively with a solvent to feed molar and reflux ratio of 2.0 and 5.0, respectively. The simulation results show the effect of the main variables on the extractive distillation process. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801637h

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Synthesis of ultrahigh molecular weight polyethylene using traditional heterogeneous ziegler-natta catalyst systems / Sudhakar Padmanabhan in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4866–4871 Titre : Synthesis of ultrahigh molecular weight polyethylene using traditional heterogeneous ziegler-natta catalyst systems Type de document : texte imprimé Auteurs : Sudhakar Padmanabhan, Auteur ; Krishna R. Sarma, Auteur ; Shashikant Sharma, Auteur Année de publication : 2009 Article en page(s) : pp. 4866–4871 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ultrahigh molecular weight polyethylene Ziegler-Natta catalysts Oxidation states Polymer Résumé : Ultrahigh molecular weight polyethylene was synthesized from traditional Ziegler−Natta type catalysts (ZN), namely, TiCl4 anchored on MgCl2 support. This, upon activation with AlRR′2 (where R, R′ = isoprenyl or isobutyl), gave precatalysts (C-2 to C-5) having 16, 21, 25, and 32% trivalent titanium, respectively. The reduction in oxidation states also accompanies the reduction in particle size of the catalysts, which in turn gets reflected in the resulting polymer properties under specified operating conditions. We have demonstrated the effect of process conditions that can surmount the catalyst dependency over the polymer characteristics, and hence, it can result in polymer with consistent polymer properties, which is an important need of the polymer industries. The polymer characteristics such as particle size distribution, average particle size, bulk density, reduced specific viscosity, and concentration of fine and coarse particles were determined and were dependent on various process parameters. Under identical reaction conditions, the polymerization with larger scale yield polymer with different characteristics. The fine-tuning of process conditions yielded polymer with consistent quality. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie802000n [article] Synthesis of ultrahigh molecular weight polyethylene using traditional heterogeneous ziegler-natta catalyst systems [texte imprimé] / Sudhakar Padmanabhan, Auteur ; Krishna R. Sarma, Auteur ; Shashikant Sharma, Auteur . - 2009 . - pp. 4866–4871. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4866–4871 Mots-clés : Ultrahigh molecular weight polyethylene Ziegler-Natta catalysts Oxidation states Polymer Résumé : Ultrahigh molecular weight polyethylene was synthesized from traditional Ziegler−Natta type catalysts (ZN), namely, TiCl4 anchored on MgCl2 support. This, upon activation with AlRR′2 (where R, R′ = isoprenyl or isobutyl), gave precatalysts (C-2 to C-5) having 16, 21, 25, and 32% trivalent titanium, respectively. The reduction in oxidation states also accompanies the reduction in particle size of the catalysts, which in turn gets reflected in the resulting polymer properties under specified operating conditions. We have demonstrated the effect of process conditions that can surmount the catalyst dependency over the polymer characteristics, and hence, it can result in polymer with consistent polymer properties, which is an important need of the polymer industries. The polymer characteristics such as particle size distribution, average particle size, bulk density, reduced specific viscosity, and concentration of fine and coarse particles were determined and were dependent on various process parameters. Under identical reaction conditions, the polymerization with larger scale yield polymer with different characteristics. The fine-tuning of process conditions yielded polymer with consistent quality. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie802000n

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Online monitoring of kappa number during batch pulping by visible spectroscopy / Wenhao Shen in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4872–4876 Titre : Online monitoring of kappa number during batch pulping by visible spectroscopy Type de document : texte imprimé Auteurs : Wenhao Shen, Auteur ; Xiaoquan Chen, Auteur Année de publication : 2009 Article en page(s) : pp. 4872–4876 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Kappa number Batch pulping Online measurement Spectroscopy Résumé : Aiming at the difficulties and problems of online measurement of pulp Kappa number during batch pulping, a novel measuring idea was proposed to predict the lignin content in pulp through the measurement of dissolved lignin in cooking liquor with spectroscopic technology. It was discovered that the spectral absorption of sulfite cooking liquor from Masson’s pine in 460−580 nm wave range resulted mainly from lignin sulfonate with high molecular weight, while saccharide and water in sulfite cooking liquor have no obvious absorption. The delignification study shows that the sulfite cooking delignification process can be observed with selected visible wavelength. Mathematical models of online Kappa number determination with visible spectroscopy were developed by chemometrics for batch sulfite pulping. After applying to sulfite pulp mill, the results showed that the new measuring method was much better than the manual method: The first-class proportion of pulp has been improved from 55% to 70%, the pulp Kappa number could be controlled within ±2 units. With this new method, it is possible not only to measure sulfite pulp Kappa number but also to perform the end point controlling of the sulfite pulping process. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie802008r [article] Online monitoring of kappa number during batch pulping by visible spectroscopy [texte imprimé] / Wenhao Shen, Auteur ; Xiaoquan Chen, Auteur . - 2009 . - pp. 4872–4876. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4872–4876 Mots-clés : Kappa number Batch pulping Online measurement Spectroscopy Résumé : Aiming at the difficulties and problems of online measurement of pulp Kappa number during batch pulping, a novel measuring idea was proposed to predict the lignin content in pulp through the measurement of dissolved lignin in cooking liquor with spectroscopic technology. It was discovered that the spectral absorption of sulfite cooking liquor from Masson’s pine in 460−580 nm wave range resulted mainly from lignin sulfonate with high molecular weight, while saccharide and water in sulfite cooking liquor have no obvious absorption. The delignification study shows that the sulfite cooking delignification process can be observed with selected visible wavelength. Mathematical models of online Kappa number determination with visible spectroscopy were developed by chemometrics for batch sulfite pulping. After applying to sulfite pulp mill, the results showed that the new measuring method was much better than the manual method: The first-class proportion of pulp has been improved from 55% to 70%, the pulp Kappa number could be controlled within ±2 units. With this new method, it is possible not only to measure sulfite pulp Kappa number but also to perform the end point controlling of the sulfite pulping process. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie802008r

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Adaptive PID controller design for nonlinear systems / Imma Nuella in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4877–4883 Titre : Adaptive PID controller design for nonlinear systems Type de document : texte imprimé Auteurs : Imma Nuella, Auteur ; Cheng Cheng, Auteur ; Min-Sen Chiu, Auteur Année de publication : 2009 Article en page(s) : pp. 4877–4883 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Adaptive proportional-integral-derivative controller Nonlinear control Just-in-time learning technique Résumé : In this paper, an adaptive proportional−integral−derivative (PID) controller design is proposed for nonlinear process control. In the proposed method, a controller database is constructed to store the PID parameters previously implemented together with their corresponding information vectors, while another modeling database is utilized by the just-in-time learning technique for modeling purpose. The PID parameters are obtained from controller database according to the current process dynamics characterized by the information vector at each sampling instance. Moreover, these PID parameters can be further fine-tuned, whenever required, and the resulting PID parameters together with the associated information vector are stored into controller database to improve it for operating conditions where the relevant information is not available in the construction of initial controller database. Simulation results are presented to illustrate the proposed adaptive PID design and its effectiveness is evaluated through comparison with its conventional counterpart. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801227d [article] Adaptive PID controller design for nonlinear systems [texte imprimé] / Imma Nuella, Auteur ; Cheng Cheng, Auteur ; Min-Sen Chiu, Auteur . - 2009 . - pp. 4877–4883. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4877–4883 Mots-clés : Adaptive proportional-integral-derivative controller Nonlinear control Just-in-time learning technique Résumé : In this paper, an adaptive proportional−integral−derivative (PID) controller design is proposed for nonlinear process control. In the proposed method, a controller database is constructed to store the PID parameters previously implemented together with their corresponding information vectors, while another modeling database is utilized by the just-in-time learning technique for modeling purpose. The PID parameters are obtained from controller database according to the current process dynamics characterized by the information vector at each sampling instance. Moreover, these PID parameters can be further fine-tuned, whenever required, and the resulting PID parameters together with the associated information vector are stored into controller database to improve it for operating conditions where the relevant information is not available in the construction of initial controller database. Simulation results are presented to illustrate the proposed adaptive PID design and its effectiveness is evaluated through comparison with its conventional counterpart. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801227d

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Optimization of the polymer foam process by the residence time distribution approach / Mathieu Larochette in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4884–4891 Titre : Optimization of the polymer foam process by the residence time distribution approach Type de document : texte imprimé Auteurs : Mathieu Larochette, Auteur ; Didier Graebling, Auteur ; Djamel Nasri, Auteur Année de publication : 2009 Article en page(s) : pp. 4884–4891 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Polystyrene foaming Residence time distribution Extrusion process Reactors Résumé : In this work, we used the residence time distribution to study the polystyrene foaming during an extrusion process. The extruder associated with a gear pump is simply and quantitatively described by three continuously stirred tank reactors with recycling loops and one plug-flow reactor. The blowing agent used is CO2 and is obtained by thermal decomposition of a chemical blowing agent (CBA). This approach allows the optimization of the density of the foam in accordance with the CBA kinetic of decomposition. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800836j [article] Optimization of the polymer foam process by the residence time distribution approach [texte imprimé] / Mathieu Larochette, Auteur ; Didier Graebling, Auteur ; Djamel Nasri, Auteur . - 2009 . - pp. 4884–4891. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4884–4891 Mots-clés : Polystyrene foaming Residence time distribution Extrusion process Reactors Résumé : In this work, we used the residence time distribution to study the polystyrene foaming during an extrusion process. The extruder associated with a gear pump is simply and quantitatively described by three continuously stirred tank reactors with recycling loops and one plug-flow reactor. The blowing agent used is CO2 and is obtained by thermal decomposition of a chemical blowing agent (CBA). This approach allows the optimization of the density of the foam in accordance with the CBA kinetic of decomposition. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800836j

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A novel statistical-based monitoring approach for complex multivariate processes / Zhiqiang Ge in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4892–4898 Titre : A novel statistical-based monitoring approach for complex multivariate processes Type de document : texte imprimé Auteurs : Zhiqiang Ge, Auteur ; Lei Xie, Auteur Année de publication : 2009 Article en page(s) : pp. 4892–4898 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Non-Gaussian variables Gaussian essential Independent component analysis Factor Résumé : Conventional methods are under the assumption that a process is driven by either non-Gaussian or Gaussian essential variables. However, many complex processes may be simultaneously driven by these two types of essential source. This paper proposes a novel independent component analysis and factor analysis (ICA-FA) method to capture the non-Gaussian and Gaussian essential variables. The non-Gaussian part is first extracted by ICA and support vector data description is utilized to obtain tight confidence limit. A probabilistic approach is subsequently incorporated to separate the residual Gaussian part into latent influential factors and unmodeled uncertainty. By retrieving the underlying process data generating structure, ICA-FA facilitates the diagnosis of process faults that occur in different sources. A further contribution of this paper is the definition of a new similarity factor based on the ICA-FA for fault identification. The efficiency of the proposed method is shown by a case study on the TE benchmark process. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800935e [article] A novel statistical-based monitoring approach for complex multivariate processes [texte imprimé] / Zhiqiang Ge, Auteur ; Lei Xie, Auteur . - 2009 . - pp. 4892–4898. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4892–4898 Mots-clés : Non-Gaussian variables Gaussian essential Independent component analysis Factor Résumé : Conventional methods are under the assumption that a process is driven by either non-Gaussian or Gaussian essential variables. However, many complex processes may be simultaneously driven by these two types of essential source. This paper proposes a novel independent component analysis and factor analysis (ICA-FA) method to capture the non-Gaussian and Gaussian essential variables. The non-Gaussian part is first extracted by ICA and support vector data description is utilized to obtain tight confidence limit. A probabilistic approach is subsequently incorporated to separate the residual Gaussian part into latent influential factors and unmodeled uncertainty. By retrieving the underlying process data generating structure, ICA-FA facilitates the diagnosis of process faults that occur in different sources. A further contribution of this paper is the definition of a new similarity factor based on the ICA-FA for fault identification. The efficiency of the proposed method is shown by a case study on the TE benchmark process. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800935e

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Genetic programming based variable interaction models for classification of process and biological systems / Raghuraj K. Rao in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4899–4907 Titre : Genetic programming based variable interaction models for classification of process and biological systems Type de document : texte imprimé Auteurs : Raghuraj K. Rao, Auteur ; Kyaw Tun, Auteur ; S. Lakshminarayanan, Auteur Année de publication : 2009 Article en page(s) : pp. 4899–4907 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Genetic programming Variable dependency models Linear classification Nonlinear Résumé : Classification of data originating from complex process and biological systems is challenging owing to the presence of multivariate and highly nonlinear interactions between variables. Patterns, difficult to distinguish using decision boundaries or available discriminating rules, can be separated based on unique inter-relations among the feature vectors. Given the complex nature of such systems, the variable interaction models are difficult to establish. Genetic programming (GP), a data-driven evolutionary modeling approach, is suggested here to be a potential tool for designing variable dependency models and exploiting them further for class discriminant analysis. Thus, this paper proposes a new GP model based classification approach. The approach is applied on illustrative data sets, and its performance is benchmarked against well-established linear and nonlinear classifiers such as LDA, kNN, CART, ANN, and SVM. It is demonstrated that GP based models can play an effective role in classification of data into multiple classes. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801147m [article] Genetic programming based variable interaction models for classification of process and biological systems [texte imprimé] / Raghuraj K. Rao, Auteur ; Kyaw Tun, Auteur ; S. Lakshminarayanan, Auteur . - 2009 . - pp. 4899–4907. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4899–4907 Mots-clés : Genetic programming Variable dependency models Linear classification Nonlinear Résumé : Classification of data originating from complex process and biological systems is challenging owing to the presence of multivariate and highly nonlinear interactions between variables. Patterns, difficult to distinguish using decision boundaries or available discriminating rules, can be separated based on unique inter-relations among the feature vectors. Given the complex nature of such systems, the variable interaction models are difficult to establish. Genetic programming (GP), a data-driven evolutionary modeling approach, is suggested here to be a potential tool for designing variable dependency models and exploiting them further for class discriminant analysis. Thus, this paper proposes a new GP model based classification approach. The approach is applied on illustrative data sets, and its performance is benchmarked against well-established linear and nonlinear classifiers such as LDA, kNN, CART, ANN, and SVM. It is demonstrated that GP based models can play an effective role in classification of data into multiple classes. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801147m

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Optimum design of battery-integrated diesel generator systems incorporating demand uncertainty / Arun P. in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4908–4916 Titre : Optimum design of battery-integrated diesel generator systems incorporating demand uncertainty Type de document : texte imprimé Auteurs : Arun P., Auteur ; Rangan Banerjee, Auteur ; Santanu Bandyopadhyay, Auteur Année de publication : 2009 Article en page(s) : pp. 4908–4916 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Diesel generator system Battery integrated Demand uncertainty System reliability values Résumé : A diesel generator system, integrated with battery, is one of the options for decentralized power production in remote locations. The principles of process system engineering along with the concept of design space approach for system design have been employed to optimize a battery integrated diesel generator system. The design space is the set of all feasible design options, generated using time series simulation of the entire system. In this paper, a methodology is proposed to appropriately size a battery integrated diesel generator system incorporating uncertainty associated with the demand. Chance constrained programming approach is combined with the design space approach to incorporate the demand uncertainty at the design stage. With a known distribution of the demand, the proposed methodology helps in identifying a sizing curve on the diesel generator rating versus storage capacity diagram for a specified reliability level. The system reliability values given by the proposed approach are validated using sequential Monte Carlo simulation approach through illustrative examples. Sets of sizing curves may be generated for different confidence levels as required by the designer. However, under the simplified assumption of a constant coefficient of variation for the demand, these sizing curves can be combined into a single curve. The cost of energy of the system is minimized to select the optimum configuration for different reliability levels. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8014236 [article] Optimum design of battery-integrated diesel generator systems incorporating demand uncertainty [texte imprimé] / Arun P., Auteur ; Rangan Banerjee, Auteur ; Santanu Bandyopadhyay, Auteur . - 2009 . - pp. 4908–4916. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4908–4916 Mots-clés : Diesel generator system Battery integrated Demand uncertainty System reliability values Résumé : A diesel generator system, integrated with battery, is one of the options for decentralized power production in remote locations. The principles of process system engineering along with the concept of design space approach for system design have been employed to optimize a battery integrated diesel generator system. The design space is the set of all feasible design options, generated using time series simulation of the entire system. In this paper, a methodology is proposed to appropriately size a battery integrated diesel generator system incorporating uncertainty associated with the demand. Chance constrained programming approach is combined with the design space approach to incorporate the demand uncertainty at the design stage. With a known distribution of the demand, the proposed methodology helps in identifying a sizing curve on the diesel generator rating versus storage capacity diagram for a specified reliability level. The system reliability values given by the proposed approach are validated using sequential Monte Carlo simulation approach through illustrative examples. Sets of sizing curves may be generated for different confidence levels as required by the designer. However, under the simplified assumption of a constant coefficient of variation for the demand, these sizing curves can be combined into a single curve. The cost of energy of the system is minimized to select the optimum configuration for different reliability levels. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8014236

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Inherent safety analysis of a propane precooled gas-phase liquified natural gas process / Nipen M. Shah in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4917–4927 Titre : Inherent safety analysis of a propane precooled gas-phase liquified natural gas process Type de document : texte imprimé Auteurs : Nipen M. Shah, Auteur ; Andrew F. A. Hoadley, Auteur Année de publication : 2009 Article en page(s) : pp. 4917–4927 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Liquified natural gas Refrigeration Propane precooling cycle Hydrocarbon reduction Résumé : Refrigeration is widely used in chemical and petrochemical industries and in the liquefaction of gases including natural gas (LNG). There are many commercial processes being used in the LNG industries. These processes are energy intensive and require large capital investment. Conventional refrigeration processes such as the single mixed refrigerant process and the cascade refrigerant process operate by evaporation of the refrigerant. Gas-phase refrigeration processes have one important advantage over these processes and this is their very low hydrocarbon inventory. However, precooling the natural gas feed stream with a conventional propane refrigeration system significantly improves the efficiency of the gas phase refrigeration process. However, due to the propane precooling cycle, the liquid hydrocarbon inventory in the process increases, and hence, the hazard potential of the overall process increases. Therefore, there is a tradeoff between the energy efficiency and the inherent safety of the process. To analyze this tradeoff, a multiobjective optimization study is performed on the propane precooled dual independent expander process. The study includes four case studies with different objectives such as the minimization of the total shaftwork requirement, the capital cost, the total annual cost, and the total hydrocarbon inventory. The cost of hydrocarbon inventory reduction is calculated from the Pareto-optimal solutions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8015939 [article] Inherent safety analysis of a propane precooled gas-phase liquified natural gas process [texte imprimé] / Nipen M. Shah, Auteur ; Andrew F. A. Hoadley, Auteur . - 2009 . - pp. 4917–4927. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4917–4927 Mots-clés : Liquified natural gas Refrigeration Propane precooling cycle Hydrocarbon reduction Résumé : Refrigeration is widely used in chemical and petrochemical industries and in the liquefaction of gases including natural gas (LNG). There are many commercial processes being used in the LNG industries. These processes are energy intensive and require large capital investment. Conventional refrigeration processes such as the single mixed refrigerant process and the cascade refrigerant process operate by evaporation of the refrigerant. Gas-phase refrigeration processes have one important advantage over these processes and this is their very low hydrocarbon inventory. However, precooling the natural gas feed stream with a conventional propane refrigeration system significantly improves the efficiency of the gas phase refrigeration process. However, due to the propane precooling cycle, the liquid hydrocarbon inventory in the process increases, and hence, the hazard potential of the overall process increases. Therefore, there is a tradeoff between the energy efficiency and the inherent safety of the process. To analyze this tradeoff, a multiobjective optimization study is performed on the propane precooled dual independent expander process. The study includes four case studies with different objectives such as the minimization of the total shaftwork requirement, the capital cost, the total annual cost, and the total hydrocarbon inventory. The cost of hydrocarbon inventory reduction is calculated from the Pareto-optimal solutions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8015939

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Effect of H2O on the desulfurization of simulated flue gas by an ionic liquid / Shuhang Ren in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4928–4932 Titre : Effect of H2O on the desulfurization of simulated flue gas by an ionic liquid Type de document : texte imprimé Auteurs : Shuhang Ren, Auteur ; Yucui Hou, Auteur ; Weize Wu, Auteur Année de publication : 2009 Article en page(s) : pp. 4928–4932 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ionic liquids SO2 Large-scale desulfurization Mixed gases Résumé : Functionalized ionic liquids (ILs) have been demonstrated to absorb SO2 from mixed gases or simulated flue gases efficiently. However, after absorbing a large amount of SO2, the viscosity of the ILs increases greatly, which might limit their eventual applications in large-scale desulfurization from mixed gases or flue gases. In this work, the effect of the presence of water in a simulated flue gas on the absorption of SO2 by a functionalized ionic liquid, 1,1,3,3-tetramethylguanidinium lactate, has been studied at different temperatures. It is found that the presence of water in the simulated flue gas can decrease the viscosity of the IL greatly, and it has no effect on the absorptivity of SO2 from the flue gas. The densities of the IL absorbing SO2 from the flue gas with or without water are also studied. They increase with the increase of the amount of SO2 absorbed from the flue gas in both cases. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9000844 [article] Effect of H2O on the desulfurization of simulated flue gas by an ionic liquid [texte imprimé] / Shuhang Ren, Auteur ; Yucui Hou, Auteur ; Weize Wu, Auteur . - 2009 . - pp. 4928–4932. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4928–4932 Mots-clés : Ionic liquids SO2 Large-scale desulfurization Mixed gases Résumé : Functionalized ionic liquids (ILs) have been demonstrated to absorb SO2 from mixed gases or simulated flue gases efficiently. However, after absorbing a large amount of SO2, the viscosity of the ILs increases greatly, which might limit their eventual applications in large-scale desulfurization from mixed gases or flue gases. In this work, the effect of the presence of water in a simulated flue gas on the absorption of SO2 by a functionalized ionic liquid, 1,1,3,3-tetramethylguanidinium lactate, has been studied at different temperatures. It is found that the presence of water in the simulated flue gas can decrease the viscosity of the IL greatly, and it has no effect on the absorptivity of SO2 from the flue gas. The densities of the IL absorbing SO2 from the flue gas with or without water are also studied. They increase with the increase of the amount of SO2 absorbed from the flue gas in both cases. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9000844

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Adding microsized silica particles to the catalysis/ultrafiltration system / Zhaoxiang Zhong in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4933–4938 Titre : Adding microsized silica particles to the catalysis/ultrafiltration system : catalyst dissolution inhibition and flux enhancement Type de document : texte imprimé Auteurs : Zhaoxiang Zhong, Auteur ; Xin Liu, Auteur ; Rizhi Chen, Auteur Année de publication : 2009 Article en page(s) : pp. 4933–4938 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Catalytic reactionCrossflow ultrafiltration Microsized silica particles Résumé : A system combining catalytic reaction with crossflow ultrafiltration (UF) was used to catalytic ammoximation of cyclohexanone to the oxime over titanium silicalite-1 (TS-1) catalysts. The effect of microsized silica particles on the performance of the catalysis/UF system was investigated in terms of catalytic activity and membrane filterability through dissolution and ultrafiltration experiments. Adding silica particles in the system inhibits the dissolution of TS-1 catalysts and increases both the reaction conversion and the selectivity significantly. Further characterizations (XRF, XRD, FTIR, etc.) indicated that the presence of silica particles remarkably limits the ammonia damage to the microstructure frame of TS-1 catalyst. In addition, silica particles play an important role in substantially removing the deposited TS-1 cake from the membrane surface, benefiting from the scouring effect. According to the results of visual observation to the tested membranes and the estimation of hydrodynamic forces acting on particles, microsized particles are hard to deposit on the membrane surface at the studied conditions and therefore a flux improvement has been achieved. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801774a [article] Adding microsized silica particles to the catalysis/ultrafiltration system : catalyst dissolution inhibition and flux enhancement [texte imprimé] / Zhaoxiang Zhong, Auteur ; Xin Liu, Auteur ; Rizhi Chen, Auteur . - 2009 . - pp. 4933–4938. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4933–4938 Mots-clés : Catalytic reactionCrossflow ultrafiltration Microsized silica particles Résumé : A system combining catalytic reaction with crossflow ultrafiltration (UF) was used to catalytic ammoximation of cyclohexanone to the oxime over titanium silicalite-1 (TS-1) catalysts. The effect of microsized silica particles on the performance of the catalysis/UF system was investigated in terms of catalytic activity and membrane filterability through dissolution and ultrafiltration experiments. Adding silica particles in the system inhibits the dissolution of TS-1 catalysts and increases both the reaction conversion and the selectivity significantly. Further characterizations (XRF, XRD, FTIR, etc.) indicated that the presence of silica particles remarkably limits the ammonia damage to the microstructure frame of TS-1 catalyst. In addition, silica particles play an important role in substantially removing the deposited TS-1 cake from the membrane surface, benefiting from the scouring effect. According to the results of visual observation to the tested membranes and the estimation of hydrodynamic forces acting on particles, microsized particles are hard to deposit on the membrane surface at the studied conditions and therefore a flux improvement has been achieved. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801774a

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Preparation of mustard (Brassica juncea L.) protein isolate and recovery of phenolic compounds by ultrafiltration / Ranjana Das in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4939–4947 Titre : Preparation of mustard (Brassica juncea L.) protein isolate and recovery of phenolic compounds by ultrafiltration Type de document : texte imprimé Auteurs : Ranjana Das, Auteur ; Chiranjib Bhattacharjee, Auteur ; Santinath Ghosh, Auteur Année de publication : 2009 Article en page(s) : pp. 4939–4947 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Mustard Ultrafiltration-diafiltration-based technique Phenolic antioxidants Résumé : Mustard (Brassica juncea L.) seed meal is good source of protein (28−36%) and phenolic antioxidants like sinapic acid and sinapine. In this work an ultrafiltration−diafiltration-based technique is developed for simultaneous preparation of protein isolate and recovery of phenolic rich fraction from seed meal using a high shear rotating disk membrane module with emphasis on reduced membrane fouling effect. The yield of membrane process found less (31.4% on dry basis) compared to precipitation process (42% on dry basis), but a high purity of protein isolate (96%) with improved functional properties was obtained. The phenolic content in the protein was found to be reduced from 7.23 mg/g of protein to as low as 0.6 mg/g of protein in this process. The phenolic-acid-rich fraction recovered shows about 87.24% radical scavenging and 34.3% chelation capacity per 100 ppm concentration. So, this process can be commercially exploited for protein isolate and phenolic antioxidant-rich product preparation after proper scale up. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801474q [article] Preparation of mustard (Brassica juncea L.) protein isolate and recovery of phenolic compounds by ultrafiltration [texte imprimé] / Ranjana Das, Auteur ; Chiranjib Bhattacharjee, Auteur ; Santinath Ghosh, Auteur . - 2009 . - pp. 4939–4947. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4939–4947 Mots-clés : Mustard Ultrafiltration-diafiltration-based technique Phenolic antioxidants Résumé : Mustard (Brassica juncea L.) seed meal is good source of protein (28−36%) and phenolic antioxidants like sinapic acid and sinapine. In this work an ultrafiltration−diafiltration-based technique is developed for simultaneous preparation of protein isolate and recovery of phenolic rich fraction from seed meal using a high shear rotating disk membrane module with emphasis on reduced membrane fouling effect. The yield of membrane process found less (31.4% on dry basis) compared to precipitation process (42% on dry basis), but a high purity of protein isolate (96%) with improved functional properties was obtained. The phenolic content in the protein was found to be reduced from 7.23 mg/g of protein to as low as 0.6 mg/g of protein in this process. The phenolic-acid-rich fraction recovered shows about 87.24% radical scavenging and 34.3% chelation capacity per 100 ppm concentration. So, this process can be commercially exploited for protein isolate and phenolic antioxidant-rich product preparation after proper scale up. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801474q

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Numerical simulation and optimal design of AGMD-based hollow fiber modules for desalination / Li-Hua Cheng in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4948–4959 Titre : Numerical simulation and optimal design of AGMD-based hollow fiber modules for desalination Type de document : texte imprimé Auteurs : Li-Hua Cheng, Auteur ; Ping-Chung Wu, Auteur ; Junghui Chen, Auteur Année de publication : 2009 Article en page(s) : pp. 4948–4959 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Air gap membrane distillation Desalination Hollow fiber Résumé : To improve the permeate flux and to keep the advantage of the high thermal efficiency in air gap membrane distillation (AGMD) for desalination, the optimal design of countercurrent AGMD of the hollow fiber module (AGMD-HF) is proposed. The module is basically composed of hydrophobic porous fiber tubes for feed flow and nonporous tubes for cold flow. The set of mathematical model equations for the entire module is derived from rigorous mass, momentum, and energy balances of both the feed side and the cold side coupled with the simultaneous mass and heat transfer across the membrane. The temperatures across the membrane and along the length of the module are simulated. The sensitivity of the process performance to operating conditions along the fiber length is investigated over a range of temperature and the flow rate. It is found that in the AGMD-HF domain, air/vapor dominates the heat and mass transfer resistances, which are comparable with the available experimental results in the literature. An attempt is then made to adjust the packing density and the surface ratio of the hot porous fibers to the cold nonporous fibers in order to maximize the process performance. Based on the trade-off between productivity and the thermal efficiency under module parameters, optimal design of AGMD-HF using Pareto solutions and the genetic algorithm is finally carried out. The obtained optimal points show that productivity increases considerably at the cost of the higher thermal efficiency with the increase of both packing density of the module and the tube ratio of hot feed fibers to cold fibers, with the latter showing relatively complex effect. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800832z [article] Numerical simulation and optimal design of AGMD-based hollow fiber modules for desalination [texte imprimé] / Li-Hua Cheng, Auteur ; Ping-Chung Wu, Auteur ; Junghui Chen, Auteur . - 2009 . - pp. 4948–4959. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4948–4959 Mots-clés : Air gap membrane distillation Desalination Hollow fiber Résumé : To improve the permeate flux and to keep the advantage of the high thermal efficiency in air gap membrane distillation (AGMD) for desalination, the optimal design of countercurrent AGMD of the hollow fiber module (AGMD-HF) is proposed. The module is basically composed of hydrophobic porous fiber tubes for feed flow and nonporous tubes for cold flow. The set of mathematical model equations for the entire module is derived from rigorous mass, momentum, and energy balances of both the feed side and the cold side coupled with the simultaneous mass and heat transfer across the membrane. The temperatures across the membrane and along the length of the module are simulated. The sensitivity of the process performance to operating conditions along the fiber length is investigated over a range of temperature and the flow rate. It is found that in the AGMD-HF domain, air/vapor dominates the heat and mass transfer resistances, which are comparable with the available experimental results in the literature. An attempt is then made to adjust the packing density and the surface ratio of the hot porous fibers to the cold nonporous fibers in order to maximize the process performance. Based on the trade-off between productivity and the thermal efficiency under module parameters, optimal design of AGMD-HF using Pareto solutions and the genetic algorithm is finally carried out. The obtained optimal points show that productivity increases considerably at the cost of the higher thermal efficiency with the increase of both packing density of the module and the tube ratio of hot feed fibers to cold fibers, with the latter showing relatively complex effect. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800832z

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Theoretical analysis to assess the separative power of reconfigured cascades of predesigned gas centrifuges / Jochen F. A. Delbeke in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4960–4965 Titre : Theoretical analysis to assess the separative power of reconfigured cascades of predesigned gas centrifuges Type de document : texte imprimé Auteurs : Jochen F. A. Delbeke, Auteur Année de publication : 2009 Article en page(s) : pp. 4960–4965 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Gas centrifuges Reconfigured cascades Résumé : An analysis is presented that describes a theoretical approach to assess the separative power of redistributions of a fixed number of predesigned gas centrifuges in reconfigured countercurrent cascades. A parameter that indicates deviations from ideal operation is derived, and this parameter facilitates the choice of likely sets of external cascade parameters. The overall loss in separative power of redistributed systems is discussed, and configurations that correspond to a minimum loss of overall separative power are presented. The application of this methodology to a specific case study that is of importance in the field of nuclear safeguards is discussed. Sample calculations simulating higher product enrichment levels are performed to determine likely cascade configurations. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8011006 [article] Theoretical analysis to assess the separative power of reconfigured cascades of predesigned gas centrifuges [texte imprimé] / Jochen F. A. Delbeke, Auteur . - 2009 . - pp. 4960–4965. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4960–4965 Mots-clés : Gas centrifuges Reconfigured cascades Résumé : An analysis is presented that describes a theoretical approach to assess the separative power of redistributions of a fixed number of predesigned gas centrifuges in reconfigured countercurrent cascades. A parameter that indicates deviations from ideal operation is derived, and this parameter facilitates the choice of likely sets of external cascade parameters. The overall loss in separative power of redistributed systems is discussed, and configurations that correspond to a minimum loss of overall separative power are presented. The application of this methodology to a specific case study that is of importance in the field of nuclear safeguards is discussed. Sample calculations simulating higher product enrichment levels are performed to determine likely cascade configurations. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8011006

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Multicomponent inverse gas chromatography / J. Román Galdámez in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4966–4974 Titre : Multicomponent inverse gas chromatography : determination of solubility and diffusivity in ternary polymer-solvent systems Type de document : texte imprimé Auteurs : J. Román Galdámez, Auteur ; Ronald P. Danner, Auteur Année de publication : 2009 Article en page(s) : pp. 4966–4974 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Inverse gas chromatography Ternary polymer-solvent-solvent system Solubility Diffusivity Résumé : The inverse gas chromatography technique was applied to measure solubility and diffusivity in a ternary polymer−solvent−solvent system. This method requires the comparison of the experimental elution profiles with theoretically predicted ones. A new simplified model was developed to describe ternary systems. In addition, a new experimental apparatus was constructed to monitor the independent composition profiles during a multicomponent experiment. The model was evaluated using experimental data for the system poly(vinyl acetate)−toluene−tetrahydrofuran at 80 and 100 °C. Solubility and diffusivity of the mixed solvents in poly(vinyl acetate) were collected at 80°. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801776g [article] Multicomponent inverse gas chromatography : determination of solubility and diffusivity in ternary polymer-solvent systems [texte imprimé] / J. Román Galdámez, Auteur ; Ronald P. Danner, Auteur . - 2009 . - pp. 4966–4974. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4966–4974 Mots-clés : Inverse gas chromatography Ternary polymer-solvent-solvent system Solubility Diffusivity Résumé : The inverse gas chromatography technique was applied to measure solubility and diffusivity in a ternary polymer−solvent−solvent system. This method requires the comparison of the experimental elution profiles with theoretically predicted ones. A new simplified model was developed to describe ternary systems. In addition, a new experimental apparatus was constructed to monitor the independent composition profiles during a multicomponent experiment. The model was evaluated using experimental data for the system poly(vinyl acetate)−toluene−tetrahydrofuran at 80 and 100 °C. Solubility and diffusivity of the mixed solvents in poly(vinyl acetate) were collected at 80°. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801776g

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Use of water-compatible polystyrene-polyglycidol resins for the separation and recovery of dissolved precious metal salts / Yu-Lung Lam in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4975–4979 Titre : Use of water-compatible polystyrene-polyglycidol resins for the separation and recovery of dissolved precious metal salts Type de document : texte imprimé Auteurs : Yu-Lung Lam, Auteur ; Die Yang, Auteur ; Chi-Yuet Chan, Auteur Année de publication : 2009 Article en page(s) : pp. 4975–4979 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Polystyrene-polyglycidol Water-compatible resins Precious metal salts Cyanide Résumé : The use of polystyrene−polyglycidol (PS/PG) water-compatible resins for the extraction of the precious metal salts gold(I) cyanide and silver(I) cyanide from aqueous phase was studied. The resins studied include polyglycidol grafted onto a polystyrene core, a thiol version of this base PS/PG resin in which the terminal hydroxyl groups are replaced with thiol groups, and a magnetic PS/PG resin. More than 99% of the gold and silver ions of the original solutions could be extracted using the resins, and reverse extraction of the loaded metal ions from the resins was performed. Thus, recycling of the resins was possible and no deterioration in extraction performance of the reused materials was observed. The attractiveness of these resins in water purification is augmented by the fact that the PS/PG resins examined can be easily synthesized from inexpensive commodity chemical starting materials. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801904h [article] Use of water-compatible polystyrene-polyglycidol resins for the separation and recovery of dissolved precious metal salts [texte imprimé] / Yu-Lung Lam, Auteur ; Die Yang, Auteur ; Chi-Yuet Chan, Auteur . - 2009 . - pp. 4975–4979. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4975–4979 Mots-clés : Polystyrene-polyglycidol Water-compatible resins Precious metal salts Cyanide Résumé : The use of polystyrene−polyglycidol (PS/PG) water-compatible resins for the extraction of the precious metal salts gold(I) cyanide and silver(I) cyanide from aqueous phase was studied. The resins studied include polyglycidol grafted onto a polystyrene core, a thiol version of this base PS/PG resin in which the terminal hydroxyl groups are replaced with thiol groups, and a magnetic PS/PG resin. More than 99% of the gold and silver ions of the original solutions could be extracted using the resins, and reverse extraction of the loaded metal ions from the resins was performed. Thus, recycling of the resins was possible and no deterioration in extraction performance of the reused materials was observed. The attractiveness of these resins in water purification is augmented by the fact that the PS/PG resins examined can be easily synthesized from inexpensive commodity chemical starting materials. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801904h

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Preparation, characterization, and application of modified chitosan sorbents for elemental mercury removal / Anchao Zhang in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4980–4989 Titre : Preparation, characterization, and application of modified chitosan sorbents for elemental mercury removal Type de document : texte imprimé Auteurs : Anchao Zhang, Auteur ; Jun Xiang, Auteur ; Lushi Sun, Auteur Année de publication : 2009 Article en page(s) : pp. 4980–4989 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Chitosan sorbents N2 isotherm adsorption/desorption method Vapor-phase elemental mercury Résumé : A series of raw, iodine (bromide) or/and sulfuric acid-modified chitosan sorbents were synthesized and comprehensively characterized by N2 isotherm adsorption/desorption method, TGA, FTIR, XRD, and XPS et al. Adsorption experiments of vapor-phase elemental mercury (Hg0) were studied using the sorbents in a laboratory-scale fixed-bed reactor. The results revealed that porosities and specific surface areas of the sorbents decreased after modification. The sorbents operated stably at flue-gas temperature below 140 °C. The chemical reactions of iodine and sulfate ion with the amide of chitosan occurred, and the I2 was found in the sorbents due to the presence of H2SO4. Fixed-bed adsorber tests showed that compared to raw chitosan, the bromide or iodine-modified chitosan could promote the efficiency of Hg0 capture more or less. Mercury removal efficiency could be significantly promoted when an appropriate content of H2SO4 was added, and the iodine and H2SO4 modified sorbents almost had a mercury removal efficiency of 100% for 3 h. The presence of moisture can increase the sorbent’s capacity for mercury uptake due to the existence of active sites, such as sulfonate and amino group. The mercury breakthrough of modified chitosan sorbents decreased with increasing temperature. A reaction scheme that could explain the experimental results was presumed based on the characterizations and adsorption study. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9000629 [article] Preparation, characterization, and application of modified chitosan sorbents for elemental mercury removal [texte imprimé] / Anchao Zhang, Auteur ; Jun Xiang, Auteur ; Lushi Sun, Auteur . - 2009 . - pp. 4980–4989. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4980–4989 Mots-clés : Chitosan sorbents N2 isotherm adsorption/desorption method Vapor-phase elemental mercury Résumé : A series of raw, iodine (bromide) or/and sulfuric acid-modified chitosan sorbents were synthesized and comprehensively characterized by N2 isotherm adsorption/desorption method, TGA, FTIR, XRD, and XPS et al. Adsorption experiments of vapor-phase elemental mercury (Hg0) were studied using the sorbents in a laboratory-scale fixed-bed reactor. The results revealed that porosities and specific surface areas of the sorbents decreased after modification. The sorbents operated stably at flue-gas temperature below 140 °C. The chemical reactions of iodine and sulfate ion with the amide of chitosan occurred, and the I2 was found in the sorbents due to the presence of H2SO4. Fixed-bed adsorber tests showed that compared to raw chitosan, the bromide or iodine-modified chitosan could promote the efficiency of Hg0 capture more or less. Mercury removal efficiency could be significantly promoted when an appropriate content of H2SO4 was added, and the iodine and H2SO4 modified sorbents almost had a mercury removal efficiency of 100% for 3 h. The presence of moisture can increase the sorbent’s capacity for mercury uptake due to the existence of active sites, such as sulfonate and amino group. The mercury breakthrough of modified chitosan sorbents decreased with increasing temperature. A reaction scheme that could explain the experimental results was presumed based on the characterizations and adsorption study. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9000629

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KT-3: a novel tickler for solids removal from slurry vessels / Richard F. Cope in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4990–4997 Titre : KT-3: a novel tickler for solids removal from slurry vessels Type de document : texte imprimé Auteurs : Richard F. Cope, Auteur ; Kishore K. Kar, Auteur Année de publication : 2009 Article en page(s) : pp. 4990–4997 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ticklers Slurry vessels Résumé : Ticklers are relatively small impellers operating near the bottom of slurry-containing stirred-tank reactors and storage vessels. They maintain solids suspension after the level of a draining slurry recedes below the main impeller(s). Typical pitched-blade or flat-blade ticklers suspend solids, but often simultaneously starve the pump and protract drainage times by throwing material out toward the wall instead of in toward the centerline discharge nozzle. After the slurry liquid eventually drains, solids deposited on the vessel bottom and wall are often removable only by extraneous liquid sprays. By contrast, the recently designed KT-3 tickler minimizes solids heels while simultaneously avoiding pump starvation and prolonged drainage times. It does so by swirling the slurry so that it washes the unbaffled vessel bottom and sweeps solids toward the centerline exit. KT-3 ticklers have been successfully installed in vessels used in many processing industries including those for basic and fine chemicals, minerals, pharmaceuticals, and food products. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801221t [article] KT-3: a novel tickler for solids removal from slurry vessels [texte imprimé] / Richard F. Cope, Auteur ; Kishore K. Kar, Auteur . - 2009 . - pp. 4990–4997. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4990–4997 Mots-clés : Ticklers Slurry vessels Résumé : Ticklers are relatively small impellers operating near the bottom of slurry-containing stirred-tank reactors and storage vessels. They maintain solids suspension after the level of a draining slurry recedes below the main impeller(s). Typical pitched-blade or flat-blade ticklers suspend solids, but often simultaneously starve the pump and protract drainage times by throwing material out toward the wall instead of in toward the centerline discharge nozzle. After the slurry liquid eventually drains, solids deposited on the vessel bottom and wall are often removable only by extraneous liquid sprays. By contrast, the recently designed KT-3 tickler minimizes solids heels while simultaneously avoiding pump starvation and prolonged drainage times. It does so by swirling the slurry so that it washes the unbaffled vessel bottom and sweeps solids toward the centerline exit. KT-3 ticklers have been successfully installed in vessels used in many processing industries including those for basic and fine chemicals, minerals, pharmaceuticals, and food products. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801221t

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Determination of toluene, n-heptane, [emim][EtSO4], and [bmim][MeSO4] ionic liquids concentrations in quaternary mixtures by UV-vis spectroscopy / José S. Torrecilla in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4998–5003 Titre : Determination of toluene, n-heptane, [emim][EtSO4], and [bmim][MeSO4] ionic liquids concentrations in quaternary mixtures by UV-vis spectroscopy Type de document : texte imprimé Auteurs : José S. Torrecilla, Auteur ; Ester Rojo, Auteur ; Julián García, Auteur Année de publication : 2009 Article en page(s) : pp. 4998–5003 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Toluene Heptane 1-ethyl-3-methylimidazolium ethylsulfate 1-butyl-3-methylimidazolium methylsulfate Ionic liquids Correlation UV−  vis absorbance Résumé : This article reports a new computerized approach to the simultaneous determination of low concentrations of toluene, heptane and 1-ethyl-3-methylimidazolium ethylsulfate ([emim][EtSO4]) and 1-butyl-3-methylimidazolium methylsulfate ([bmim][MeSO4]) ionic liquids (ILs) in acetone using a correlation between their concentrations and UV−vis absorbance values. The essential information (absorbance data) from UV−vis spectrometer of quaternary mixtures in acetone was selected by a principal component analysis (PCA) and transferred into linear regressions (LRs) or neural network (NN) trained computer to estimate the concentrations. Such an integrated PCA/NN/UV−vis spectroscopy system is capable of estimating the concentrations of chemicals in acetone, based on the created models and patterns, without any previous phenomenological knowledge. The mean difference between the estimated concentrations using the PCA/NN/UV−vis and the real concentrations of toluene, heptane, [emim][EtSO4], and [bmim][MeSO4] is less than 2.5%. The PCA/NN/UV−vis is one of the first reliable approaches that can be used in the ILs mixtures field to determine the concentration of two ILs and hydrocarbons in quaternary mixtures while at the same time having simple applications. The short time required by PCA/NN/UV−vis to measure all four chemicals makes it especially useful in processes where long sample preparation times are required. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8014044 [article] Determination of toluene, n-heptane, [emim][EtSO4], and [bmim][MeSO4] ionic liquids concentrations in quaternary mixtures by UV-vis spectroscopy [texte imprimé] / José S. Torrecilla, Auteur ; Ester Rojo, Auteur ; Julián García, Auteur . - 2009 . - pp. 4998–5003. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 4998–5003 Mots-clés : Toluene Heptane 1-ethyl-3-methylimidazolium ethylsulfate 1-butyl-3-methylimidazolium methylsulfate Ionic liquids Correlation UV−  vis absorbance Résumé : This article reports a new computerized approach to the simultaneous determination of low concentrations of toluene, heptane and 1-ethyl-3-methylimidazolium ethylsulfate ([emim][EtSO4]) and 1-butyl-3-methylimidazolium methylsulfate ([bmim][MeSO4]) ionic liquids (ILs) in acetone using a correlation between their concentrations and UV−vis absorbance values. The essential information (absorbance data) from UV−vis spectrometer of quaternary mixtures in acetone was selected by a principal component analysis (PCA) and transferred into linear regressions (LRs) or neural network (NN) trained computer to estimate the concentrations. Such an integrated PCA/NN/UV−vis spectroscopy system is capable of estimating the concentrations of chemicals in acetone, based on the created models and patterns, without any previous phenomenological knowledge. The mean difference between the estimated concentrations using the PCA/NN/UV−vis and the real concentrations of toluene, heptane, [emim][EtSO4], and [bmim][MeSO4] is less than 2.5%. The PCA/NN/UV−vis is one of the first reliable approaches that can be used in the ILs mixtures field to determine the concentration of two ILs and hydrocarbons in quaternary mixtures while at the same time having simple applications. The short time required by PCA/NN/UV−vis to measure all four chemicals makes it especially useful in processes where long sample preparation times are required. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8014044

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Investigation of micromixing efficiency in a novel high-throughput microporous tube-in-tube microchannel reactor / Qi-An Wang in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5004–5009 Titre : Investigation of micromixing efficiency in a novel high-throughput microporous tube-in-tube microchannel reactor Type de document : texte imprimé Auteurs : Qi-An Wang, Auteur ; Jie-Xin Wang, Auteur ; Wen Yu, Auteur Année de publication : 2009 Article en page(s) : pp. 5004–5009 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Microporous tube-in-tube microchannel reactor Throughput Micromixing performance Résumé : This article presents a new microporous tube-in-tube microchannel reactor (MTMCR) with high throughput and excellent micromixing performance. In the MTMCR, one liquid from the inner tube is divided into many liquid fragments through the microscale pores in the walls, and then these fragments vertically collide with another flowing annular liquid sheet between the inner and outer tubes, generating cross-flow. The annular microchannel allows a mass of fluid to go through it rapidly without enlarging the channel width, thereby achieving a throughput as high as 9 L/min (typical microreactor throughput = 4−100 mL/min). Furthermore, the micromixing performance is expressed in terms of a segregation index, which can be as low as 0.0007. The micromixing time evaluated by the incorporation model reaches the magnitude of milliseconds. In addition, several factors affecting the micromixing such as reactant concentration, flow rate, volume flow ratio, micropore size, and channel width were investigated. The results indicated that an increase of the flow rate, as well as a reduction of the micropore size and channel width, could greatly intensify the micromixing. Therefore, it can be envisioned that the MTMCR would exhibit great potential for various industrial applications in the future. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801424r [article] Investigation of micromixing efficiency in a novel high-throughput microporous tube-in-tube microchannel reactor [texte imprimé] / Qi-An Wang, Auteur ; Jie-Xin Wang, Auteur ; Wen Yu, Auteur . - 2009 . - pp. 5004–5009. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5004–5009 Mots-clés : Microporous tube-in-tube microchannel reactor Throughput Micromixing performance Résumé : This article presents a new microporous tube-in-tube microchannel reactor (MTMCR) with high throughput and excellent micromixing performance. In the MTMCR, one liquid from the inner tube is divided into many liquid fragments through the microscale pores in the walls, and then these fragments vertically collide with another flowing annular liquid sheet between the inner and outer tubes, generating cross-flow. The annular microchannel allows a mass of fluid to go through it rapidly without enlarging the channel width, thereby achieving a throughput as high as 9 L/min (typical microreactor throughput = 4−100 mL/min). Furthermore, the micromixing performance is expressed in terms of a segregation index, which can be as low as 0.0007. The micromixing time evaluated by the incorporation model reaches the magnitude of milliseconds. In addition, several factors affecting the micromixing such as reactant concentration, flow rate, volume flow ratio, micropore size, and channel width were investigated. The results indicated that an increase of the flow rate, as well as a reduction of the micropore size and channel width, could greatly intensify the micromixing. Therefore, it can be envisioned that the MTMCR would exhibit great potential for various industrial applications in the future. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801424r

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Novel approach to characterize fluidized bed dynamics combining particle image velocimetry and finite element method / J. A. Almendros-Ibáñez in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5010–5023 Titre : Novel approach to characterize fluidized bed dynamics combining particle image velocimetry and finite element method Type de document : texte imprimé Auteurs : J. A. Almendros-Ibáñez, Auteur ; D. Pallarès, Auteur ; F. Johnsson, Auteur Année de publication : 2009 Article en page(s) : pp. 5010–5023 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Combining particle image velocimetry Digital analysis Finite element method Bubbling fluidized bed Résumé : This work presents a new experimental−numerical method combining PIV (particle image velocimetry), digital image analysis, and FEM (finite element method) to obtain gas and particle motion around bubbles in a 2D freely bubbling fluidized bed. The bubble geometry is captured with a high speed video camera while the particle velocity is measured using a PIV technique. These experimental data are exported to a finite element software where the pressure and gas velocity fields are obtained numerically. The flow equations proposed by Davidson’s model have been chosen to exemplify the application of the method presented in this paper. Different bubble types have been analyzed: slow and fast bubbles but also erupting and interacting bubbles. The effect on the gas flow of bubbles with a nonzero horizontal velocity component has also been analyzed, and it is shown how such bubbles interchange gas with the main stream. In addition, the Darcy’s law included in Davidson’s model has been extended including a quadratic term (i.e., Ergun’s equation) to take into account non-Darcy effects and the PIV results have been used to evaluate the error committed when voidage variation around bubbles is neglected. The results obtained including non-Darcy effects show differences in the gas velocity magnitude in regions near the nose and the wake of the bubble, where the gas velocity and, consequently, the local Reynolds number are higher. Nevertheless, these local differences give no significante difference in the gas streamlines around bubbles. Finally, the study of the voidage variation around bubbles shows that this variation is important only in a region of small thickness adjacent to the bubble. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801720g [article] Novel approach to characterize fluidized bed dynamics combining particle image velocimetry and finite element method [texte imprimé] / J. A. Almendros-Ibáñez, Auteur ; D. Pallarès, Auteur ; F. Johnsson, Auteur . - 2009 . - pp. 5010–5023. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5010–5023 Mots-clés : Combining particle image velocimetry Digital analysis Finite element method Bubbling fluidized bed Résumé : This work presents a new experimental−numerical method combining PIV (particle image velocimetry), digital image analysis, and FEM (finite element method) to obtain gas and particle motion around bubbles in a 2D freely bubbling fluidized bed. The bubble geometry is captured with a high speed video camera while the particle velocity is measured using a PIV technique. These experimental data are exported to a finite element software where the pressure and gas velocity fields are obtained numerically. The flow equations proposed by Davidson’s model have been chosen to exemplify the application of the method presented in this paper. Different bubble types have been analyzed: slow and fast bubbles but also erupting and interacting bubbles. The effect on the gas flow of bubbles with a nonzero horizontal velocity component has also been analyzed, and it is shown how such bubbles interchange gas with the main stream. In addition, the Darcy’s law included in Davidson’s model has been extended including a quadratic term (i.e., Ergun’s equation) to take into account non-Darcy effects and the PIV results have been used to evaluate the error committed when voidage variation around bubbles is neglected. The results obtained including non-Darcy effects show differences in the gas velocity magnitude in regions near the nose and the wake of the bubble, where the gas velocity and, consequently, the local Reynolds number are higher. Nevertheless, these local differences give no significante difference in the gas streamlines around bubbles. Finally, the study of the voidage variation around bubbles shows that this variation is important only in a region of small thickness adjacent to the bubble. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801720g

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Effects of coal interaction with supercritical CO2 / Benson B. Gathitu in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5024–5034 Titre : Effects of coal interaction with supercritical CO2 : physical structure Type de document : texte imprimé Auteurs : Benson B. Gathitu, Auteur ; Wei-Yin Chen, Auteur ; Michael McClure, Auteur Année de publication : 2009 Article en page(s) : pp. 5024–5034 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Coal Gas sorption technique Scanning electron microscope CO2 Résumé : It is known that polar solvents swell coal, break hydrogen-bonds in the macromolecular structure, and enhance coal liquefaction efficiencies. The effects of drying, interaction with supercritical CO2 and degassing on the physical structure of coal have been studied using gas sorption technique and a scanning electron microscope (SEM). Both drying and interaction with supercritical CO2 drastically change the micropore and mesopore surface area, absolute volume, and volume distribution in both bituminous coal and lignite. Degassing removes debris in the pore space which allows for better analysis of the changes in the morphology that were induced by drying and exposure to supercritical CO2. SEM reveals that interaction of bituminous coal with supercritical CO2 results in an abundance of carbon structures similar to the maceral collinite. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9000162 [article] Effects of coal interaction with supercritical CO2 : physical structure [texte imprimé] / Benson B. Gathitu, Auteur ; Wei-Yin Chen, Auteur ; Michael McClure, Auteur . - 2009 . - pp. 5024–5034. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5024–5034 Mots-clés : Coal Gas sorption technique Scanning electron microscope CO2 Résumé : It is known that polar solvents swell coal, break hydrogen-bonds in the macromolecular structure, and enhance coal liquefaction efficiencies. The effects of drying, interaction with supercritical CO2 and degassing on the physical structure of coal have been studied using gas sorption technique and a scanning electron microscope (SEM). Both drying and interaction with supercritical CO2 drastically change the micropore and mesopore surface area, absolute volume, and volume distribution in both bituminous coal and lignite. Degassing removes debris in the pore space which allows for better analysis of the changes in the morphology that were induced by drying and exposure to supercritical CO2. SEM reveals that interaction of bituminous coal with supercritical CO2 results in an abundance of carbon structures similar to the maceral collinite. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9000162

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Extension of the Elliott-Suresh-Donohue equation of state to dipolar systems / Farzad Alavi in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5035–5045 Titre : Extension of the Elliott-Suresh-Donohue equation of state to dipolar systems Type de document : texte imprimé Auteurs : Farzad Alavi, Auteur ; Farzaneh Feyzi, Auteur Année de publication : 2009 Article en page(s) : pp. 5035–5045 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Elliott−  Suresh−  Donohue equation of state Dipolar systems Square-well reference Vapor−  liquid equilibrium Liquid−  liquid Résumé : The Elliott−Suresh−Donohue (ESD) equation of state (EOS) is extended to dipolar systems by adding a contribution as perturbation to the Helmholtz energy of the system. The polar contribution is based on the Padé approximation for square-well (SW) reference potential. Pure compound parameters of the new equation were regressed by vapor pressure and saturated density analyses. The parameters were then generalized for nonassociating compounds based on the data for 38 slightly polar substances, mostly including hydrocarbons. Using the polar perturbation term, the accuracy of the ESD EOS to predict saturation properties of pure components is improved in both generalized (nonassociating) and nongeneralized (associating) forms. The proposed model is applied to vapor−liquid equilibrium (VLE) and liquid−liquid equilibrium (LLE) in binary polar systems including associating compounds. Using the polar contribution, the required binary interaction parameter was decreased in comparison with the ESD EOS. By some illustrations, it is demonstrated that the polar perturbation term improves the accuracy and applicability of the ESD EOS. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800689f [article] Extension of the Elliott-Suresh-Donohue equation of state to dipolar systems [texte imprimé] / Farzad Alavi, Auteur ; Farzaneh Feyzi, Auteur . - 2009 . - pp. 5035–5045. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5035–5045 Mots-clés : Elliott−  Suresh−  Donohue equation of state Dipolar systems Square-well reference Vapor−  liquid equilibrium Liquid−  liquid Résumé : The Elliott−Suresh−Donohue (ESD) equation of state (EOS) is extended to dipolar systems by adding a contribution as perturbation to the Helmholtz energy of the system. The polar contribution is based on the Padé approximation for square-well (SW) reference potential. Pure compound parameters of the new equation were regressed by vapor pressure and saturated density analyses. The parameters were then generalized for nonassociating compounds based on the data for 38 slightly polar substances, mostly including hydrocarbons. Using the polar perturbation term, the accuracy of the ESD EOS to predict saturation properties of pure components is improved in both generalized (nonassociating) and nongeneralized (associating) forms. The proposed model is applied to vapor−liquid equilibrium (VLE) and liquid−liquid equilibrium (LLE) in binary polar systems including associating compounds. Using the polar contribution, the required binary interaction parameter was decreased in comparison with the ESD EOS. By some illustrations, it is demonstrated that the polar perturbation term improves the accuracy and applicability of the ESD EOS. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800689f

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Evaluation of local turbulent energy dissipation rate using PIV in jet loop reactor / Sagar S. Deshpande in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5046–5057 Titre : Evaluation of local turbulent energy dissipation rate using PIV in jet loop reactor Type de document : texte imprimé Auteurs : Sagar S. Deshpande, Auteur ; Mayur J. Sathe, Auteur ; Jyeshtharaj B. Joshi, Auteur Année de publication : 2009 Article en page(s) : pp. 5046–5057 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Jet loop reactors Particle image velocimetry Laser Doppler Hot film anemometry Turbulent dissipation rate Résumé : In the present work, experimental analysis has been carried out for jet loop reactors to investigate the mean and turbulence parameters. Measurements have been made using particle image velocimetry (PIV), laser Doppler velocimetry (LDV), and hot film anemometry (HFA). The major aim of this work is to evaluate the local value of turbulent dissipation rate (ε) using PIV. LDV has been used as a benchmark for analyzing the mean flow quantities, while HFA has been mainly used for the evaluation of energy spectra. Thus, the relative strength of these instruments was harnessed for better understanding of the flow pattern. A method has been proposed for the evaluation of ε from the experimental data from PIV and HFA based on structure function relationships and 3D energy spectrum. Overall energy balance has been satisfied implicitly to make the method of ε estimation more robust. As an application, the values of ε obtained from the CFD predictions (Large eddy simulations) have been compared with that of the experimental values showing opportunity for improved design of turbulence based on local ε variations. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8007924 [article] Evaluation of local turbulent energy dissipation rate using PIV in jet loop reactor [texte imprimé] / Sagar S. Deshpande, Auteur ; Mayur J. Sathe, Auteur ; Jyeshtharaj B. Joshi, Auteur . - 2009 . - pp. 5046–5057. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5046–5057 Mots-clés : Jet loop reactors Particle image velocimetry Laser Doppler Hot film anemometry Turbulent dissipation rate Résumé : In the present work, experimental analysis has been carried out for jet loop reactors to investigate the mean and turbulence parameters. Measurements have been made using particle image velocimetry (PIV), laser Doppler velocimetry (LDV), and hot film anemometry (HFA). The major aim of this work is to evaluate the local value of turbulent dissipation rate (ε) using PIV. LDV has been used as a benchmark for analyzing the mean flow quantities, while HFA has been mainly used for the evaluation of energy spectra. Thus, the relative strength of these instruments was harnessed for better understanding of the flow pattern. A method has been proposed for the evaluation of ε from the experimental data from PIV and HFA based on structure function relationships and 3D energy spectrum. Overall energy balance has been satisfied implicitly to make the method of ε estimation more robust. As an application, the values of ε obtained from the CFD predictions (Large eddy simulations) have been compared with that of the experimental values showing opportunity for improved design of turbulence based on local ε variations. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8007924

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Investigation of mutual solubility in the NH4VO3−NH4NO3−H2O system / Mieczyslaw Trypuc in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5058–5063 Titre : Investigation of mutual solubility in the NH4VO3−NH4NO3−H2O system Type de document : texte imprimé Auteurs : Mieczyslaw Trypuc, Auteur ; Sebastian Druzynski, Auteur Année de publication : 2009 Article en page(s) : pp. 5058–5063 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ammonium vanadate nitrate NH4VO3−  NH4NO3−  H2O system Isothermal saturation method Résumé : The solubilities of ammonium vanadate and ammonium nitrate in the NH4VO3−NH4NO3−H2O system were investigated at 293, 303, 313, and 323 K by the method of isothermal saturation of solutions. A section of the solubility isotherm for the investigated system was plotted based on the obtained data. Knowledge of that dependence is necessary for developing the new method of using the postfiltration liquor from the soda−chlorine−saltpeter (SCS) method of sodium carbonate production, based on an equilibrium plot for the quaternary system of pairs of the exchange salts NH4NO3−NaVO3−H2O. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801341j [article] Investigation of mutual solubility in the NH4VO3−NH4NO3−H2O system [texte imprimé] / Mieczyslaw Trypuc, Auteur ; Sebastian Druzynski, Auteur . - 2009 . - pp. 5058–5063. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5058–5063 Mots-clés : Ammonium vanadate nitrate NH4VO3−  NH4NO3−  H2O system Isothermal saturation method Résumé : The solubilities of ammonium vanadate and ammonium nitrate in the NH4VO3−NH4NO3−H2O system were investigated at 293, 303, 313, and 323 K by the method of isothermal saturation of solutions. A section of the solubility isotherm for the investigated system was plotted based on the obtained data. Knowledge of that dependence is necessary for developing the new method of using the postfiltration liquor from the soda−chlorine−saltpeter (SCS) method of sodium carbonate production, based on an equilibrium plot for the quaternary system of pairs of the exchange salts NH4NO3−NaVO3−H2O. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801341j

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Prediction of the upper flammability limits of organic compounds from molecular structures / Yong Pan in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5064–5069 Titre : Prediction of the upper flammability limits of organic compounds from molecular structures Type de document : texte imprimé Auteurs : Yong Pan, Auteur ; Juncheng Jiang, Auteur ; Rui, Wang, Auteur Année de publication : 2009 Article en page(s) : pp. 5064–5069 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Organic compounds Upper flammability limits Genetic algorithm Multiple linear regression Résumé : A quantitative structure−property relationship (QSPR) study is performed to develop mathematical models for prediction of the upper flammability limits (UFL) of organic compounds from their molecular structures. The structural features of the compounds are numerically represented by various kinds of calculated molecular descriptors such as topological, charge, and geometric descriptors. The genetic algorithm combined with multiple linear regression (GA-MLR) is used to select an optimal subset of descriptors that have significant contribution to the overall UFL property from the large pool of calculated descriptors. The best resulted model is a four-variable multilinear model with a defined applicability range. The average absolute error and root-mean-square error obtained for the external test set are 1.75 vol % and 2.77, respectively. The proposed model can be used to predict the UFL of organic compounds with only four preselected theoretical descriptors which can be directly calculated from molecular structure alone. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900193r [article] Prediction of the upper flammability limits of organic compounds from molecular structures [texte imprimé] / Yong Pan, Auteur ; Juncheng Jiang, Auteur ; Rui, Wang, Auteur . - 2009 . - pp. 5064–5069. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5064–5069 Mots-clés : Organic compounds Upper flammability limits Genetic algorithm Multiple linear regression Résumé : A quantitative structure−property relationship (QSPR) study is performed to develop mathematical models for prediction of the upper flammability limits (UFL) of organic compounds from their molecular structures. The structural features of the compounds are numerically represented by various kinds of calculated molecular descriptors such as topological, charge, and geometric descriptors. The genetic algorithm combined with multiple linear regression (GA-MLR) is used to select an optimal subset of descriptors that have significant contribution to the overall UFL property from the large pool of calculated descriptors. The best resulted model is a four-variable multilinear model with a defined applicability range. The average absolute error and root-mean-square error obtained for the external test set are 1.75 vol % and 2.77, respectively. The proposed model can be used to predict the UFL of organic compounds with only four preselected theoretical descriptors which can be directly calculated from molecular structure alone. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900193r

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Preparation and characterization of inclusion complexes of β-cyclodextrin−BITC and β-cyclodextrin−PEITC / Hai-Na Yuan in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5070–5078 Titre : Preparation and characterization of inclusion complexes of β-cyclodextrin−BITC and β-cyclodextrin−PEITC Type de document : texte imprimé Auteurs : Hai-Na Yuan, Auteur ; Shan-Jing Yao, Auteur ; Lian-Qing Shen, Auteur Année de publication : 2009 Article en page(s) : pp. 5070–5078 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Benzyl isothiocyanate Phenylethyl Inclusion complexes Response surface design Résumé : Benzyl isothiocyanate (BITC) and phenylethyl isothiocyanate (PEITC) are two poorly water-soluble plant components that can form inclusion complexes with β-cyclodextrin (β-CD), namely, β-cyclodextrin−BITC and β-cyclodextrin−PEITC, that are two water-soluble complexes. The inclusion complexes were prepared by two independent processes: physical mixing and coprecipitation. The content of guest molecules in the complexes was measured by UV spectrophotometry. Response surface design (RSD) was applied to optimize the preparation conditions of said complexes. The results showed that the embedding ratios for β-CD−BITC and β-CD−PEITC were 94.9% and 94.1%, respectively. Variance analysis revealed that the mass ratio and the inclusion temperature were two important factors in terms of inclusion action. The optimum conditions for the inclusion of β-CD−BITC were a mass ratio of 0.17 and an inclusion temperature of 57.99 °C, and those for β-CD−PEITC were a mass ratio of 0.0057 and an inclusion temperature of 64.87 °C. The inclusion complexes prepared were qualified by thermal methods [thermogravimetry (TG) and differential scanning calorimetry (DSC)], Fourier transform infrared (FTIR) spectroscopy, and X-ray powder diffraction (XRD). The thermal analysis of β-CD and the two complexes indicated that an interaction between the guest and host molecules did occur. BITC and PEITC could be partially embedded in the hydrophobic cavity of β-CD, so the formation of the said complexes was established. The X-ray and FTIR results support this indication of inclusion behavior. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8015329 [article] Preparation and characterization of inclusion complexes of β-cyclodextrin−BITC and β-cyclodextrin−PEITC [texte imprimé] / Hai-Na Yuan, Auteur ; Shan-Jing Yao, Auteur ; Lian-Qing Shen, Auteur . - 2009 . - pp. 5070–5078. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5070–5078 Mots-clés : Benzyl isothiocyanate Phenylethyl Inclusion complexes Response surface design Résumé : Benzyl isothiocyanate (BITC) and phenylethyl isothiocyanate (PEITC) are two poorly water-soluble plant components that can form inclusion complexes with β-cyclodextrin (β-CD), namely, β-cyclodextrin−BITC and β-cyclodextrin−PEITC, that are two water-soluble complexes. The inclusion complexes were prepared by two independent processes: physical mixing and coprecipitation. The content of guest molecules in the complexes was measured by UV spectrophotometry. Response surface design (RSD) was applied to optimize the preparation conditions of said complexes. The results showed that the embedding ratios for β-CD−BITC and β-CD−PEITC were 94.9% and 94.1%, respectively. Variance analysis revealed that the mass ratio and the inclusion temperature were two important factors in terms of inclusion action. The optimum conditions for the inclusion of β-CD−BITC were a mass ratio of 0.17 and an inclusion temperature of 57.99 °C, and those for β-CD−PEITC were a mass ratio of 0.0057 and an inclusion temperature of 64.87 °C. The inclusion complexes prepared were qualified by thermal methods [thermogravimetry (TG) and differential scanning calorimetry (DSC)], Fourier transform infrared (FTIR) spectroscopy, and X-ray powder diffraction (XRD). The thermal analysis of β-CD and the two complexes indicated that an interaction between the guest and host molecules did occur. BITC and PEITC could be partially embedded in the hydrophobic cavity of β-CD, so the formation of the said complexes was established. The X-ray and FTIR results support this indication of inclusion behavior. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8015329

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Extension of Tao-Mason equation of state to mixtures / Fakhri Yousefi in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5079–5084 Titre : Extension of Tao-Mason equation of state to mixtures : results for PVTx properties of refrigerants fluid mixtures Type de document : texte imprimé Auteurs : Fakhri Yousefi, Auteur ; Jalil Moghadasi, Auteur ; Mohammad Mehdi Papari, Auteur Année de publication : 2009 Article en page(s) : pp. 5079–5084 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Tao-Mason equation of state Refrigerant fluid mixtures Résumé : Tao and Mason ( J. Chem. Phys.1994, 100, 9075−9084) developed a statistical-mechanical-based equation of state (EOS) for pure substances. In the present study, we have successfully extended this EOS to fluid mixtures, selecting refrigerant fluid mixtures as the test systems. The considered refrigerant mixtures are R32 + R125, R32 + R134a, R134a + R152a, R125 + R143a, R125 + R134a, R32 + R227ea, R134a + R290, and R22 + R152a. The second virial coefficient, B(T), necessary for the mixture version of the Tao−Mason (TM) EOS, was determined using a two-parameter corresponding-states correlation obtained from the analysis of the speed of sound data and two constants: the enthalpy of vaporization ΔHvap and the molar density ρnb, both at the normal boiling point. Other temperature-dependent quantities, including the correction factor α(T) and van der Waals covolume b(T), were obtained from the Lennard-Jones (12−6) model potential. The cross parameters B12(T), α12(T), and b12(T), required by the EOS for mixtures, were determined with the help of simple combining rules. The constructed mixture version of the TM EOS was extensively tested by comparison with experimental data. The results show that the molar gas and liquid densities of the refrigerant mixtures of interest can be predicted to within 1.3% and 2.69%, respectively, over the temperature range of 253−440 K and the pressure range of 0.33−158 bar. The present EOS was further assessed through comparisons with the Ihm−Song−Mason (ISM) and Peng−Robinson (PR) equations of state. In the gas phase, the TM EOS outperforms the two other equations of state. In the liquid phase, there is no noticeable difference between the TM EOS and the PR EOS, but both work better than the ISM EOS. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8016658 [article] Extension of Tao-Mason equation of state to mixtures : results for PVTx properties of refrigerants fluid mixtures [texte imprimé] / Fakhri Yousefi, Auteur ; Jalil Moghadasi, Auteur ; Mohammad Mehdi Papari, Auteur . - 2009 . - pp. 5079–5084. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5079–5084 Mots-clés : Tao-Mason equation of state Refrigerant fluid mixtures Résumé : Tao and Mason ( J. Chem. Phys.1994, 100, 9075−9084) developed a statistical-mechanical-based equation of state (EOS) for pure substances. In the present study, we have successfully extended this EOS to fluid mixtures, selecting refrigerant fluid mixtures as the test systems. The considered refrigerant mixtures are R32 + R125, R32 + R134a, R134a + R152a, R125 + R143a, R125 + R134a, R32 + R227ea, R134a + R290, and R22 + R152a. The second virial coefficient, B(T), necessary for the mixture version of the Tao−Mason (TM) EOS, was determined using a two-parameter corresponding-states correlation obtained from the analysis of the speed of sound data and two constants: the enthalpy of vaporization ΔHvap and the molar density ρnb, both at the normal boiling point. Other temperature-dependent quantities, including the correction factor α(T) and van der Waals covolume b(T), were obtained from the Lennard-Jones (12−6) model potential. The cross parameters B12(T), α12(T), and b12(T), required by the EOS for mixtures, were determined with the help of simple combining rules. The constructed mixture version of the TM EOS was extensively tested by comparison with experimental data. The results show that the molar gas and liquid densities of the refrigerant mixtures of interest can be predicted to within 1.3% and 2.69%, respectively, over the temperature range of 253−440 K and the pressure range of 0.33−158 bar. The present EOS was further assessed through comparisons with the Ihm−Song−Mason (ISM) and Peng−Robinson (PR) equations of state. In the gas phase, the TM EOS outperforms the two other equations of state. In the liquid phase, there is no noticeable difference between the TM EOS and the PR EOS, but both work better than the ISM EOS. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8016658

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Anionic surfactants removal by natural coagulant/flocculant products / J. Beltrán-Heredia in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5085–5092 Titre : Anionic surfactants removal by natural coagulant/flocculant products Type de document : texte imprimé Auteurs : J. Beltrán-Heredia, Auteur ; J. Sánchez-Martín, Auteur ; C. Solera-Hernández, Auteur Année de publication : 2009 Article en page(s) : pp. 5085–5092 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Coagulant agent Flocculant Sodium dodecyl benzene sulfonate Anionic surfactant Résumé : A new tannin-based coagulant and flocculant agent has been tested on the removal of sodium dodecyl benzene sulfonate (SDBS), a dangerous and pollutant anionic surfactant. It is called Tanfloc and consists of a chemically modified tannin extract from Acacia mearnsii de Wild. Tanfloc has been revealed as an efficient product in anionic surfactant removal. Around 70% of SDBS removal has been achieved with Tanfloc doses of 150 mg·L−1. pH has a negative influence on surfactant removal, while the higher the initial surfactant concentration is the higher q capacity is obtained. Theoretical data adjustment has been carried out according to three different models: Frumkin−Fowler−Guggenheim (FFG), Gu and Zhu (G−Z), and Freundlich (F). Adjustment parameters have been obtained with r2 levels above 0.90 in all cases. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801913y [article] Anionic surfactants removal by natural coagulant/flocculant products [texte imprimé] / J. Beltrán-Heredia, Auteur ; J. Sánchez-Martín, Auteur ; C. Solera-Hernández, Auteur . - 2009 . - pp. 5085–5092. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5085–5092 Mots-clés : Coagulant agent Flocculant Sodium dodecyl benzene sulfonate Anionic surfactant Résumé : A new tannin-based coagulant and flocculant agent has been tested on the removal of sodium dodecyl benzene sulfonate (SDBS), a dangerous and pollutant anionic surfactant. It is called Tanfloc and consists of a chemically modified tannin extract from Acacia mearnsii de Wild. Tanfloc has been revealed as an efficient product in anionic surfactant removal. Around 70% of SDBS removal has been achieved with Tanfloc doses of 150 mg·L−1. pH has a negative influence on surfactant removal, while the higher the initial surfactant concentration is the higher q capacity is obtained. Theoretical data adjustment has been carried out according to three different models: Frumkin−Fowler−Guggenheim (FFG), Gu and Zhu (G−Z), and Freundlich (F). Adjustment parameters have been obtained with r2 levels above 0.90 in all cases. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801913y

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Acetone influence on glass transition of poly(methyl methacrylate) and polystyrene in compressed carbon dioxide / Jun He in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5093–5097 Titre : Acetone influence on glass transition of poly(methyl methacrylate) and polystyrene in compressed carbon dioxide Type de document : texte imprimé Auteurs : Jun He, Auteur ; Bo Wang, Auteur Année de publication : 2009 Article en page(s) : pp. 5093–5097 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Poly(methyl methacrylate) Polystyrene Compressed gaseous acetone/carbon dioxide Glass transition pressure Résumé : In this work, the glass transitions of poly(methyl methacrylate) and polystyrene in compressed gaseous acetone/carbon dioxide were measured by an in situ creep compliance method at pressures lower than 7.0 MPa and at 318−338 K. When a small amount of acetone (x = 0.01−0.02) was added to a polymer-compressed carbon dioxide system, the glass transition pressure of polymer was further depressed by 1.0−4.0 MPa. The observed glass transition pressure depression increased with the acetone concentration in carbon dioxide and decreased with the temperature rise. A simple model was used to estimate the glass transition temperature depressions for the polymers in compressed gaseous acetone/carbon dioxide solution. The calculated results were in good agreement with the determined ones, except for the retrograde vitrification region. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801949g [article] Acetone influence on glass transition of poly(methyl methacrylate) and polystyrene in compressed carbon dioxide [texte imprimé] / Jun He, Auteur ; Bo Wang, Auteur . - 2009 . - pp. 5093–5097. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5093–5097 Mots-clés : Poly(methyl methacrylate) Polystyrene Compressed gaseous acetone/carbon dioxide Glass transition pressure Résumé : In this work, the glass transitions of poly(methyl methacrylate) and polystyrene in compressed gaseous acetone/carbon dioxide were measured by an in situ creep compliance method at pressures lower than 7.0 MPa and at 318−338 K. When a small amount of acetone (x = 0.01−0.02) was added to a polymer-compressed carbon dioxide system, the glass transition pressure of polymer was further depressed by 1.0−4.0 MPa. The observed glass transition pressure depression increased with the acetone concentration in carbon dioxide and decreased with the temperature rise. A simple model was used to estimate the glass transition temperature depressions for the polymers in compressed gaseous acetone/carbon dioxide solution. The calculated results were in good agreement with the determined ones, except for the retrograde vitrification region. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801949g

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Sulfate and surfactants as boosters of kraft lignin precipitation / Magnus Norgren in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5098–5104 Titre : Sulfate and surfactants as boosters of kraft lignin precipitation Type de document : texte imprimé Auteurs : Magnus Norgren, Auteur ; Sofia Mackin, Auteur Année de publication : 2009 Article en page(s) : pp. 5098–5104 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Salts Surfactants Kraft lignin precipitation Résumé : In the spirit of the biorefinery concept, an increasing interest in further utilization of technical lignins outside the pulp mills has arisen. In this context optimization of the precipitation process to increase the yield of the lignin recovered is of great importance. The objectives of this investigation have been to study how specific salts and surfactants affect kraft lignin yield during precipitation and washing. From the results it was seen that additions of sodium sulfate increased the yield of precipitation at elevated temperatures at much lower concentrations than sodium chloride. Earlier studies of the effect of monovalent salts on kraft lignin stability have shown that specific ions either increase or decrease the formation of precipitates during kraft lignin aggregation. Thus, the presented results in this study further strengthen this dependency concerning divalent anions. Regarding the role of surfactants as precipitation enhancers, cationic surfactants gave rise to fast aggregation and relatively high yields. This was found mainly due to attractive electrostatic interactions between the cationic surfactant headgroup and the oppositely charged groups on the kraft lignin macromolecules, introducing an increased degree of hydrophobicity of the lignin and thus a decreased stability. The nonionic surfactants tested affected the system very differently. In some cases the aggregation was fast and the aggregates became relatively large before settling, whereas some surfactants induced the formation of relatively dense precipitates that settled rapidly. Concerning kraft lignin precipitate washing, calcium chloride at concentrations in the millimolar region decreased the lignin losses dramatically. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900141s [article] Sulfate and surfactants as boosters of kraft lignin precipitation [texte imprimé] / Magnus Norgren, Auteur ; Sofia Mackin, Auteur . - 2009 . - pp. 5098–5104. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5098–5104 Mots-clés : Salts Surfactants Kraft lignin precipitation Résumé : In the spirit of the biorefinery concept, an increasing interest in further utilization of technical lignins outside the pulp mills has arisen. In this context optimization of the precipitation process to increase the yield of the lignin recovered is of great importance. The objectives of this investigation have been to study how specific salts and surfactants affect kraft lignin yield during precipitation and washing. From the results it was seen that additions of sodium sulfate increased the yield of precipitation at elevated temperatures at much lower concentrations than sodium chloride. Earlier studies of the effect of monovalent salts on kraft lignin stability have shown that specific ions either increase or decrease the formation of precipitates during kraft lignin aggregation. Thus, the presented results in this study further strengthen this dependency concerning divalent anions. Regarding the role of surfactants as precipitation enhancers, cationic surfactants gave rise to fast aggregation and relatively high yields. This was found mainly due to attractive electrostatic interactions between the cationic surfactant headgroup and the oppositely charged groups on the kraft lignin macromolecules, introducing an increased degree of hydrophobicity of the lignin and thus a decreased stability. The nonionic surfactants tested affected the system very differently. In some cases the aggregation was fast and the aggregates became relatively large before settling, whereas some surfactants induced the formation of relatively dense precipitates that settled rapidly. Concerning kraft lignin precipitate washing, calcium chloride at concentrations in the millimolar region decreased the lignin losses dramatically. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900141s

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A semiempirical kinetics for modeling and simulation of the crystal growth process in pure solutions / K. Vasanth Kumar in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5105–5110 Titre : A semiempirical kinetics for modeling and simulation of the crystal growth process in pure solutions Type de document : texte imprimé Auteurs : K. Vasanth Kumar, Auteur Année de publication : 2009 Article en page(s) : pp. 5105–5110 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Crystal growth Kinetics Solid-phase concentration Crystallization rate Résumé : A kinetic model was proposed to explain the growth of crystals in pure solutions based on the solid-phase concentration, assuming that the crystal growth process follows a pseudo-second-order kinetics. The initial crystallization rate was defined based on the pseudo-second-order kinetics. The proposed model was determined to be useful in predicting the rate constant, the solid-phase concentration at equilibrium, and the initial crystallization rate. The pseudo-second-order kinetic model was applied to the experimental data of the sucrose crystal growth process for different operating temperatures and seed crystal diameters. The proposed model was accurate in modeling the experimental kinetics of sucrose crystallization process for the range of operating conditions studied. The coefficient of determination between experimental data and predicted kinetics varied from r2 = 0.943 to r2 = 0.982 at the studied temperatures. The calculated kinetic parameters were used to generate three-dimensional empirical correlations relating the crystal growth of sucrose for the range of temperature studied. The proposed model was very simple with only two unknown parameters, which can be easily determined by a simple linear or nonlinear regression analysis. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8018565 [article] A semiempirical kinetics for modeling and simulation of the crystal growth process in pure solutions [texte imprimé] / K. Vasanth Kumar, Auteur . - 2009 . - pp. 5105–5110. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5105–5110 Mots-clés : Crystal growth Kinetics Solid-phase concentration Crystallization rate Résumé : A kinetic model was proposed to explain the growth of crystals in pure solutions based on the solid-phase concentration, assuming that the crystal growth process follows a pseudo-second-order kinetics. The initial crystallization rate was defined based on the pseudo-second-order kinetics. The proposed model was determined to be useful in predicting the rate constant, the solid-phase concentration at equilibrium, and the initial crystallization rate. The pseudo-second-order kinetic model was applied to the experimental data of the sucrose crystal growth process for different operating temperatures and seed crystal diameters. The proposed model was accurate in modeling the experimental kinetics of sucrose crystallization process for the range of operating conditions studied. The coefficient of determination between experimental data and predicted kinetics varied from r2 = 0.943 to r2 = 0.982 at the studied temperatures. The calculated kinetic parameters were used to generate three-dimensional empirical correlations relating the crystal growth of sucrose for the range of temperature studied. The proposed model was very simple with only two unknown parameters, which can be easily determined by a simple linear or nonlinear regression analysis. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8018565

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Batch distillation in a column with a side withdrawal for separation of a ternary mixture with a decomposing reaction / Xianbao Cui in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5111–5116 Titre : Batch distillation in a column with a side withdrawal for separation of a ternary mixture with a decomposing reaction Type de document : texte imprimé Auteurs : Xianbao Cui, Auteur ; Ying Zhang, Auteur ; Tianyang Feng, Auteur Année de publication : 2009 Article en page(s) : pp. 5111–5116 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ternary mixture Decomposing reaction Batch distillation column GEAR integration method Résumé : The separation of a ternary mixture with a decomposing reaction was investigated in a batch distillation column with a side withdrawal (BDS). The process was simulated by a constant molar holdup model solved by the GEAR integration method and optimized by a simulated annealing algorithm. Comparing to the batch rectifier and middle vessel batch distillation column, BDS is favorable for the purification of an intermediate component from light and heavy impurities with a decomposing reaction. The effects of top reflux ratio and side reflux ratio were also investigated. Different combinations of top and side reflux ratio result in different types of product withdrawal, and the optimal operation tends to be in a large top reflux ratio and a small side reflux ratio. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8017934 [article] Batch distillation in a column with a side withdrawal for separation of a ternary mixture with a decomposing reaction [texte imprimé] / Xianbao Cui, Auteur ; Ying Zhang, Auteur ; Tianyang Feng, Auteur . - 2009 . - pp. 5111–5116. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5111–5116 Mots-clés : Ternary mixture Decomposing reaction Batch distillation column GEAR integration method Résumé : The separation of a ternary mixture with a decomposing reaction was investigated in a batch distillation column with a side withdrawal (BDS). The process was simulated by a constant molar holdup model solved by the GEAR integration method and optimized by a simulated annealing algorithm. Comparing to the batch rectifier and middle vessel batch distillation column, BDS is favorable for the purification of an intermediate component from light and heavy impurities with a decomposing reaction. The effects of top reflux ratio and side reflux ratio were also investigated. Different combinations of top and side reflux ratio result in different types of product withdrawal, and the optimal operation tends to be in a large top reflux ratio and a small side reflux ratio. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8017934

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Effect of acid treatment on the high-temperature surface oxidation behavior of FeCrAlloy foil used for methane combustion catalyst support / Dong Zhang in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5117–5122 Titre : Effect of acid treatment on the high-temperature surface oxidation behavior of FeCrAlloy foil used for methane combustion catalyst support Type de document : texte imprimé Auteurs : Dong Zhang, Auteur ; Lihong Zhang, Auteur ; Bin Liang, Auteur Année de publication : 2009 Article en page(s) : pp. 5117–5122 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Acid treatment Fe−  Cr−  Al alloy Oxidation Résumé : The effect of acid treatment on the high-temperature oxidation behavior of Fe−Cr−Al alloy has been examined with oxidation tests and various characterization techniques. Acid treatment effectively improves the stability of the alloy in a high-temperature oxidation environment. After the treatment, the alloy oxidizes at a higher rate in the induction period and a lower rate in the subsequent time period. A passivative oxide layer was determined to be better formed during high-temperature oxidation on the surface of the acid-treated alloy, which suppressed further oxidation. It was observed that the oxidation rate of the alloy at high temperature can be described precisely by the Quadakkers equation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8019664 [article] Effect of acid treatment on the high-temperature surface oxidation behavior of FeCrAlloy foil used for methane combustion catalyst support [texte imprimé] / Dong Zhang, Auteur ; Lihong Zhang, Auteur ; Bin Liang, Auteur . - 2009 . - pp. 5117–5122. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5117–5122 Mots-clés : Acid treatment Fe−  Cr−  Al alloy Oxidation Résumé : The effect of acid treatment on the high-temperature oxidation behavior of Fe−Cr−Al alloy has been examined with oxidation tests and various characterization techniques. Acid treatment effectively improves the stability of the alloy in a high-temperature oxidation environment. After the treatment, the alloy oxidizes at a higher rate in the induction period and a lower rate in the subsequent time period. A passivative oxide layer was determined to be better formed during high-temperature oxidation on the surface of the acid-treated alloy, which suppressed further oxidation. It was observed that the oxidation rate of the alloy at high temperature can be described precisely by the Quadakkers equation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8019664

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Tensile stress relaxation studies of TiO2 and nanosilica filled natural rubber composites / A. P. Meera in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - p. 5123 Titre : Tensile stress relaxation studies of TiO2 and nanosilica filled natural rubber composites Type de document : texte imprimé Auteurs : A. P. Meera, Auteur ; Sylvère Said, Auteur ; Yves Grohens, Auteur Année de publication : 2009 Article en page(s) : p. 5123 Note générale : Chemical engineering Addition and correction of the same article in volume 48 n° 7, pp. 3410-3416 Langues : Anglais (eng) En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9005029 [article] Tensile stress relaxation studies of TiO2 and nanosilica filled natural rubber composites [texte imprimé] / A. P. Meera, Auteur ; Sylvère Said, Auteur ; Yves Grohens, Auteur . - 2009 . - p. 5123. Chemical engineering Addition and correction of the same article in volume 48 n° 7, pp. 3410-3416 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - p. 5123 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9005029

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