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Vol. 50 N° 16 - Août 2011 [texte imprimé] . - 2011 . - p. 9479-9828 : ill. ; 28 cm. Chemical engineering Langues : Anglais (eng)
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Ajouter le résultat dans votre panierIncorporation of silver ions into zirconium titanium phosphate / Niranjan Biswal in Industrial & engineering chemistry research, Vol. 50 N° 16 (Août 2011)
Titre : Incorporation of silver ions into zirconium titanium phosphate : a novel approach toward antibacterial activity Type de document : texte imprimé Auteurs : Niranjan Biswal, Auteur ; Satyabadi Martha, Auteur ; Umakanta Subudhi, Auteur Année de publication : 2011 Article en page(s) : pp. 9479-9486 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ions Zirconium Titanium Phosphate Résumé : Silver exchanged zirconium titanium phosphates (Ag–ZTPs) are interesting materials because of their best antibacterial performance toward Escherichia coli (E. coli). Silver ions were incorporated into zirconium titanium phosphate (ZTP), a composite ion-exchanger, by an ion-exchange process conducted at 65 °C. This study focuses on the most thorough investigation of their synthesis, optical spectroscopy, absorption band (vibrational and rotational levels) spectra, morphology studies, elemental analysis, and antibacterial activity. Silver-exchanged zirconium titanium phosphates (Ag–ZTPs) were characterized by XRD (BAXS), DRUV–vis, FTIR, XPS, SEM-EDS, TEM, and AAS measurement. Silver ions are incorporated into ZTP which is well-known from X-ray photoelectron study, transmission electron microscopy, and energy dispersive spectra. It was found that 250 mg L–1 of 5 wt % Ag–ZTP possesses high antibacterial activity with 99% inhibition within 12 h of contact. Therefore, the present results strongly suggest the effective use of silver-exchanged zirconium titanium phosphates as antibacterial agents. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102199b
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9479-9486[article] Incorporation of silver ions into zirconium titanium phosphate : a novel approach toward antibacterial activity [texte imprimé] / Niranjan Biswal, Auteur ; Satyabadi Martha, Auteur ; Umakanta Subudhi, Auteur . - 2011 . - pp. 9479-9486.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9479-9486
Mots-clés : Ions Zirconium Titanium Phosphate Résumé : Silver exchanged zirconium titanium phosphates (Ag–ZTPs) are interesting materials because of their best antibacterial performance toward Escherichia coli (E. coli). Silver ions were incorporated into zirconium titanium phosphate (ZTP), a composite ion-exchanger, by an ion-exchange process conducted at 65 °C. This study focuses on the most thorough investigation of their synthesis, optical spectroscopy, absorption band (vibrational and rotational levels) spectra, morphology studies, elemental analysis, and antibacterial activity. Silver-exchanged zirconium titanium phosphates (Ag–ZTPs) were characterized by XRD (BAXS), DRUV–vis, FTIR, XPS, SEM-EDS, TEM, and AAS measurement. Silver ions are incorporated into ZTP which is well-known from X-ray photoelectron study, transmission electron microscopy, and energy dispersive spectra. It was found that 250 mg L–1 of 5 wt % Ag–ZTP possesses high antibacterial activity with 99% inhibition within 12 h of contact. Therefore, the present results strongly suggest the effective use of silver-exchanged zirconium titanium phosphates as antibacterial agents. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102199b Exemplaires
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Titre : Green thermal analysis technology for evaluating the thermal hazard of di-tert-butyl peroxide Type de document : texte imprimé Auteurs : Jo-Ming Tseng, Auteur Année de publication : 2011 Article en page(s) : pp. 9487–9494 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hazard Thermal analysis Résumé : Di-tert-butyl peroxide (DTBP) has been widely employed in chemical industries. Unfortunately, many serious explosions and fires have occurred during the manufacturing process, storage, and transportation of organic peroxides. This study investigated the thermokinetic parameters by isothermal-kinetic and nonisothermal-kinetic simulation, using differential scanning calorimetry (DSC) tests. Green thermal analysis technology was applied to assess the kinetic parameters, such as the kinetic model, frequency factor (ln k0), activation energy (Ea), reaction order, heat of reaction (ΔHd), etc. Comparisons of nonisothermal and isothermal kinetic model simulation led to a beneficial kinetic model of thermal decomposition to predict the thermal hazard of DTBP. Simulations in 0.5 L Dewar vessel and 25 kg barrel commercial package in liquid thermal explosion models were performed and compared to the results in the literature. From the results, we determined the DTBP of the optimal conditions to avoid violent runaway reactions during the storage and transportation. This study established the features of green thermal analysis technology that could be executed as a reduction of energy potential and storage conditions in view of loss prevention. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425189
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9487–9494[article] Green thermal analysis technology for evaluating the thermal hazard of di-tert-butyl peroxide [texte imprimé] / Jo-Ming Tseng, Auteur . - 2011 . - pp. 9487–9494.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9487–9494
Mots-clés : Hazard Thermal analysis Résumé : Di-tert-butyl peroxide (DTBP) has been widely employed in chemical industries. Unfortunately, many serious explosions and fires have occurred during the manufacturing process, storage, and transportation of organic peroxides. This study investigated the thermokinetic parameters by isothermal-kinetic and nonisothermal-kinetic simulation, using differential scanning calorimetry (DSC) tests. Green thermal analysis technology was applied to assess the kinetic parameters, such as the kinetic model, frequency factor (ln k0), activation energy (Ea), reaction order, heat of reaction (ΔHd), etc. Comparisons of nonisothermal and isothermal kinetic model simulation led to a beneficial kinetic model of thermal decomposition to predict the thermal hazard of DTBP. Simulations in 0.5 L Dewar vessel and 25 kg barrel commercial package in liquid thermal explosion models were performed and compared to the results in the literature. From the results, we determined the DTBP of the optimal conditions to avoid violent runaway reactions during the storage and transportation. This study established the features of green thermal analysis technology that could be executed as a reduction of energy potential and storage conditions in view of loss prevention. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425189 Exemplaires
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Titre : Waste catalyst utilization : extraction of valuable metals from spent hydroprocessing catalysts by ultrasonic-assisted leaching with acids Type de document : texte imprimé Auteurs : M. Marafi, Auteur ; A. Stanislaus, Auteur Année de publication : 2011 Article en page(s) : pp.9495–9501 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Waste catalyst Hydroprocessing catalysts Résumé : Every year large quantities of spent hydroprocessing catalysts containing high concentrations of metals such as Mo, V, Ni, and Co are discarded as solid wastes from the petroleum refining industries. The metals present in the spent catalysts can be leached by water and pollute the environment. As these catalysts are hazardous wastes, landfills or other treatment methods for disposal are not preferable when all costs and liabilities are taken into account. Intensive efforts have been made in recent years on the development of processes for recycling and utilization of the waste catalyst materials as much as possible. Recovery of the valuable metals from the spent catalysts is an attractive option for their recycling and utilization. In the present work, the influence of ultrasonic agitation in enhancing the extraction of valuable metals such as Mo, V, and Ni from spent hydroprocessing catalysts by acid leaching was investigated. Two acids, one inorganic (H2SO4) and the other organic (citric acid), were used in the study. Citric acid was more active than H2SO4 for leaching metals from the spent catalyst. A comparison of the effectiveness of ultrasonic agitation and conventional mechanical stirring in the acid-leaching experiments conducted in the present study clearly demonstrated that ultrasonic vibration was more effective for the extraction of metals present in the spent catalyst. The leaching rate was enhanced by ultrasound, and large percentages (>95%) of all valuable metals (Mo, V, and Ni) present in the spent catalyst were extracted in a short time at a relatively low temperature (e.g., 60 °C) by combined use of citric acid and ultrasound. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200789u
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp.9495–9501[article] Waste catalyst utilization : extraction of valuable metals from spent hydroprocessing catalysts by ultrasonic-assisted leaching with acids [texte imprimé] / M. Marafi, Auteur ; A. Stanislaus, Auteur . - 2011 . - pp.9495–9501.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp.9495–9501
Mots-clés : Waste catalyst Hydroprocessing catalysts Résumé : Every year large quantities of spent hydroprocessing catalysts containing high concentrations of metals such as Mo, V, Ni, and Co are discarded as solid wastes from the petroleum refining industries. The metals present in the spent catalysts can be leached by water and pollute the environment. As these catalysts are hazardous wastes, landfills or other treatment methods for disposal are not preferable when all costs and liabilities are taken into account. Intensive efforts have been made in recent years on the development of processes for recycling and utilization of the waste catalyst materials as much as possible. Recovery of the valuable metals from the spent catalysts is an attractive option for their recycling and utilization. In the present work, the influence of ultrasonic agitation in enhancing the extraction of valuable metals such as Mo, V, and Ni from spent hydroprocessing catalysts by acid leaching was investigated. Two acids, one inorganic (H2SO4) and the other organic (citric acid), were used in the study. Citric acid was more active than H2SO4 for leaching metals from the spent catalyst. A comparison of the effectiveness of ultrasonic agitation and conventional mechanical stirring in the acid-leaching experiments conducted in the present study clearly demonstrated that ultrasonic vibration was more effective for the extraction of metals present in the spent catalyst. The leaching rate was enhanced by ultrasound, and large percentages (>95%) of all valuable metals (Mo, V, and Ni) present in the spent catalyst were extracted in a short time at a relatively low temperature (e.g., 60 °C) by combined use of citric acid and ultrasound. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200789u Exemplaires
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Titre : Fuel reformation and hydrogen generation with direct droplet impingement reactors : model formulation and validation Type de document : texte imprimé Auteurs : Mark J. Varady, Auteur ; Andrei G. Fedorov, Auteur Année de publication : 2011 Article en page(s) : pp. 9502-9513 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Modeling Reactor Droplet Hydrogen production Fuel Résumé : Onboard fuel reforming to produce hydrogen for portable fuel cell applications has been widely studied because the liquid has a high volumetric density as an energy storage medium. Several portable fuel reforming devices presented in the literature attempt to scale down the designs of traditional large-scale unit operations, an approach that becomes suboptimal as the size of the application is reduced. Unique reactor designs in which the various unit operations are combined in a synergistic manner are required to achieve higher energy densities and more compact reactors. Spraying a finely atomized liquid directly onto a hot catalyst is one such method that has been experimentally demonstrated. This work focuses on developing a fundamental understanding of this approach and optimizing it by utilizing a droplet generator array with precise control over the droplet spating, diameter, velocity, and trajectory, thus providing ultimate control over the reactor performance. The regular nature of the droplet generator array also enables modeling on a reactor-unit-cell basis with minimal empiricism, which can be used to optimize the reactor performance. The steady-state unit-cell model developed in this work accounts for the transport and evaporation of the droplet stream, impingement and subsequent film accumulation and vaporization, and gas-phase transport and reaction. The key components of the model were validated using relevant results from the literature to establish confidence in applying the complete model to predict reactor performance. Further, a reactor prototype mimicking the reactor unit cell used in the simulations was constructed and used to experimentally validate the comprehensive transport-reaction model for the specific case of methanol steam reforming, In a companion article, this complete model was used to study the effects of reactor operating parameters on conversion selectivity, and power density, aiming at an optimal reactor design. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425191
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9502-9513[article] Fuel reformation and hydrogen generation with direct droplet impingement reactors : model formulation and validation [texte imprimé] / Mark J. Varady, Auteur ; Andrei G. Fedorov, Auteur . - 2011 . - pp. 9502-9513.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9502-9513
Mots-clés : Modeling Reactor Droplet Hydrogen production Fuel Résumé : Onboard fuel reforming to produce hydrogen for portable fuel cell applications has been widely studied because the liquid has a high volumetric density as an energy storage medium. Several portable fuel reforming devices presented in the literature attempt to scale down the designs of traditional large-scale unit operations, an approach that becomes suboptimal as the size of the application is reduced. Unique reactor designs in which the various unit operations are combined in a synergistic manner are required to achieve higher energy densities and more compact reactors. Spraying a finely atomized liquid directly onto a hot catalyst is one such method that has been experimentally demonstrated. This work focuses on developing a fundamental understanding of this approach and optimizing it by utilizing a droplet generator array with precise control over the droplet spating, diameter, velocity, and trajectory, thus providing ultimate control over the reactor performance. The regular nature of the droplet generator array also enables modeling on a reactor-unit-cell basis with minimal empiricism, which can be used to optimize the reactor performance. The steady-state unit-cell model developed in this work accounts for the transport and evaporation of the droplet stream, impingement and subsequent film accumulation and vaporization, and gas-phase transport and reaction. The key components of the model were validated using relevant results from the literature to establish confidence in applying the complete model to predict reactor performance. Further, a reactor prototype mimicking the reactor unit cell used in the simulations was constructed and used to experimentally validate the comprehensive transport-reaction model for the specific case of methanol steam reforming, In a companion article, this complete model was used to study the effects of reactor operating parameters on conversion selectivity, and power density, aiming at an optimal reactor design. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425191 Exemplaires
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Titre : Fuel reformation and hydrogen generation with direct droplet impingement reactors : parametric study and design considerations for portable methanol steam reformers Type de document : texte imprimé Auteurs : Mark J. Varady, Auteur ; Andrei G. Fedorov, Auteur Année de publication : 2011 Article en page(s) : pp. 9514-9524 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Water vapor Design Reactor Droplet Hydrogen production Fuel Résumé : In a companion article (Varady and Fedorov Ind. Eng. Chem. Res. 2011, DOI: 10.1021/ie200563e), the concept of a direct droplet impingement reactor (DDIR) was introduced as a promising approach to liquid fuel reformation for distributed hydrogen generation. Considering the overall device as an array of unit cells enabled simplified modeling of the device on a unit-cell basis. In this study, the unit-cell model is utilized to study the effects of the important reactor operating parameters for the specific case of methanol steam reforming. The performance of the baseline DDIR is compared to the ideal limit of an isothermal plug-flow reactor (PFR). The effects of DDIR shape, size, heat input and location, and droplet initial conditions were varied from the baseline design to identify possible performance improvements. It was found that the selectivity displays a distinct marimum at a Pedet number (Pe) of ∼3 because of the interplay between back-diffusion of the products and thermal resistance of the catalyst bed. The spatial heating distribution also plays a key role, where an optimized matching of the heat input locations to the areas of heat consumption due to liquid vaporization and endothermic reaction results in an improved reactor performance, albeit at the penalty of a more complex reactor design and increased cost. Impingement of the droplet stream on the catalyst interface is necessary for proper operation, which requires certain initial droplet conditions to be satisfied, as expressed in the form of an operating regime map. Although the results are presented only for methanol steam reforming, the DDIR model is comprehensive and sufficiently general in terms of incorporated physical phenomena that it should be useful for developing similar operating criteria for other fuels and reactions requiring vaporization of a liquid feed followed by reaction over a fixed catalyst bed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425192
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9514-9524[article] Fuel reformation and hydrogen generation with direct droplet impingement reactors : parametric study and design considerations for portable methanol steam reformers [texte imprimé] / Mark J. Varady, Auteur ; Andrei G. Fedorov, Auteur . - 2011 . - pp. 9514-9524.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9514-9524
Mots-clés : Water vapor Design Reactor Droplet Hydrogen production Fuel Résumé : In a companion article (Varady and Fedorov Ind. Eng. Chem. Res. 2011, DOI: 10.1021/ie200563e), the concept of a direct droplet impingement reactor (DDIR) was introduced as a promising approach to liquid fuel reformation for distributed hydrogen generation. Considering the overall device as an array of unit cells enabled simplified modeling of the device on a unit-cell basis. In this study, the unit-cell model is utilized to study the effects of the important reactor operating parameters for the specific case of methanol steam reforming. The performance of the baseline DDIR is compared to the ideal limit of an isothermal plug-flow reactor (PFR). The effects of DDIR shape, size, heat input and location, and droplet initial conditions were varied from the baseline design to identify possible performance improvements. It was found that the selectivity displays a distinct marimum at a Pedet number (Pe) of ∼3 because of the interplay between back-diffusion of the products and thermal resistance of the catalyst bed. The spatial heating distribution also plays a key role, where an optimized matching of the heat input locations to the areas of heat consumption due to liquid vaporization and endothermic reaction results in an improved reactor performance, albeit at the penalty of a more complex reactor design and increased cost. Impingement of the droplet stream on the catalyst interface is necessary for proper operation, which requires certain initial droplet conditions to be satisfied, as expressed in the form of an operating regime map. Although the results are presented only for methanol steam reforming, the DDIR model is comprehensive and sufficiently general in terms of incorporated physical phenomena that it should be useful for developing similar operating criteria for other fuels and reactions requiring vaporization of a liquid feed followed by reaction over a fixed catalyst bed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425192 Exemplaires
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Titre : II. Electrodeposition/removal of nickel in a spouted electrochemical reactor Type de document : texte imprimé Auteurs : Pengpeng Grimshaw, Auteur ; Joseph M. Calo, Auteur ; Pezhman A. Shirvanian, Auteur Année de publication : 2011 Article en page(s) : pp. 9525-9531 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Electrochemical reactor Electrodeposition Résumé : An investigation is presented of nickel electrodeposition from acidic solutions in a cylindrical spouted electrochemical reactor. The effects of solution pH, temperature, and applied current on nickel removal/recovery rate, current efficiency, and corrosion rate of deposited nickel on the cathodic particles were explored under galvanostatic operation. Nitrogen sparging was used to decrease the dissolved oxygen concentration in the electrolyte in order to reduce the nickel corrosion rate, thereby increasing the nickel electrowinning rate and current efficiency. A numerical model of electrodeposition, including corrosion and mass transfer in the particulate cathode moving bed, is presented that describes the behavior of the experimental net nickel electrodeposition data quite well. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425193
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9525-9531[article] II. Electrodeposition/removal of nickel in a spouted electrochemical reactor [texte imprimé] / Pengpeng Grimshaw, Auteur ; Joseph M. Calo, Auteur ; Pezhman A. Shirvanian, Auteur . - 2011 . - pp. 9525-9531.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9525-9531
Mots-clés : Electrochemical reactor Electrodeposition Résumé : An investigation is presented of nickel electrodeposition from acidic solutions in a cylindrical spouted electrochemical reactor. The effects of solution pH, temperature, and applied current on nickel removal/recovery rate, current efficiency, and corrosion rate of deposited nickel on the cathodic particles were explored under galvanostatic operation. Nitrogen sparging was used to decrease the dissolved oxygen concentration in the electrolyte in order to reduce the nickel corrosion rate, thereby increasing the nickel electrowinning rate and current efficiency. A numerical model of electrodeposition, including corrosion and mass transfer in the particulate cathode moving bed, is presented that describes the behavior of the experimental net nickel electrodeposition data quite well. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425193 Exemplaires
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Titre : III. Co-electrodeposition/removal of copper and nickel in a spouted electrochemical reactor Type de document : texte imprimé Auteurs : Pengpeng Grimshaw, Auteur ; Joseph M. Calo, Auteur ; George Hradil, Auteur Année de publication : 2011 Article en page(s) : pp. 9532–9538 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Copper Nickel Electrochemical reactor Résumé : Results are presented of an investigation of the co-electrodeposition of copper and nickel from acidic solution mixtures in a cylindrical spouted electrochemical reactor. The effects of solution pH, temperature, and applied current on the metal removal/recovery rate, current efficiency, and corrosion of the deposited metals from the cathodic particles were examined under galvanostatic operation. The quantitative and qualitative behavior of co-electrodeposition of the two metals from their mixtures differs significantly from that of the individual single-metal solutions. This is primarily attributed to the metal displacement reaction between Ni0 and Cu2+. This reaction effectively reduces the corrosion of copper and amplifies that of nickel (at least at high concentrations). It also amplifies the separation of the deposition regimes of the two metals in time, which indicates that the recovery of each metal as a relatively pure deposit from the mixture is possible. It was also shown that nitrogen sparging considerably increases the observed net electrodeposition rates for both metals, considerably more so than from solutions with just the single metals alone. A numerical model of co-electrodeposition, corrosion, metal displacement, and mass transfer in the cylindrical spouted electrochemical reactor is presented that describes the behavior of the experimental copper and nickel removal data quite well. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200670g
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9532–9538[article] III. Co-electrodeposition/removal of copper and nickel in a spouted electrochemical reactor [texte imprimé] / Pengpeng Grimshaw, Auteur ; Joseph M. Calo, Auteur ; George Hradil, Auteur . - 2011 . - pp. 9532–9538.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9532–9538
Mots-clés : Copper Nickel Electrochemical reactor Résumé : Results are presented of an investigation of the co-electrodeposition of copper and nickel from acidic solution mixtures in a cylindrical spouted electrochemical reactor. The effects of solution pH, temperature, and applied current on the metal removal/recovery rate, current efficiency, and corrosion of the deposited metals from the cathodic particles were examined under galvanostatic operation. The quantitative and qualitative behavior of co-electrodeposition of the two metals from their mixtures differs significantly from that of the individual single-metal solutions. This is primarily attributed to the metal displacement reaction between Ni0 and Cu2+. This reaction effectively reduces the corrosion of copper and amplifies that of nickel (at least at high concentrations). It also amplifies the separation of the deposition regimes of the two metals in time, which indicates that the recovery of each metal as a relatively pure deposit from the mixture is possible. It was also shown that nitrogen sparging considerably increases the observed net electrodeposition rates for both metals, considerably more so than from solutions with just the single metals alone. A numerical model of co-electrodeposition, corrosion, metal displacement, and mass transfer in the cylindrical spouted electrochemical reactor is presented that describes the behavior of the experimental copper and nickel removal data quite well. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200670g Exemplaires
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Titre : Mechanism and in vitro release kinetic study of sirolimus from a biodegradable polymeric matrix coated cardiovascular stent Type de document : texte imprimé Auteurs : Ankur Raval, Auteur ; Jigisha Parikh, Auteur ; Chhaya Engineer, Auteur Année de publication : 2011 Article en page(s) : pp. 9539-9549 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetics Résumé : Implantation of Drug Eluting Stents (DES) is the most accepted technique currently available to treat cardiovascular blockages. First generation DES uses polymers for drug delivery which are nondegradable in nature and remains attached to stent surface lifetime. Biodegradable polymers have gained immense attention for controlled drug delivery of therapeutic drugs from cardiovascular stents in recent times as nondegradable polymers are associated with long-term adverse events. Studies showed that permanent contact with this polymer creates local inflammatory reactions and long-term stent thrombosis which raises concerns over the widespread use of DES. Biodegradable polymers are widely accepted biomaterials in human health care area and have proved its biocompatibility as drug delivery vehicle in various medicinal applications. This research work is carried out to study mechanisms affecting drug release kinetics from coated cardiovascular stents composed of biodegradable poly lactide-co-caprolactone and polyvinyl pyrrolidone. A conventional air brush technique was effectively modified so that Co-Cr L605 metallic stents were coated within multiple layers having drug Sirolimus blended together with biodegradable polymeric matrix. Kinetic studies for drug dissolution from a stent are carried out in simulated biological fluid using high performance liquid chromatography (HPLC) with simultaneous monitoring of surface morphology by scanning electron microscopy (SEM). Drug elution data analyzed by mathematical models suggested a combination of surface drug dissolution and diffusion as major drug release mechanisms. Investigation of different top coats revealed that drug release is influenced by the hydrophobicity of the drug free protective layer. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425195
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9539-9549[article] Mechanism and in vitro release kinetic study of sirolimus from a biodegradable polymeric matrix coated cardiovascular stent [texte imprimé] / Ankur Raval, Auteur ; Jigisha Parikh, Auteur ; Chhaya Engineer, Auteur . - 2011 . - pp. 9539-9549.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9539-9549
Mots-clés : Kinetics Résumé : Implantation of Drug Eluting Stents (DES) is the most accepted technique currently available to treat cardiovascular blockages. First generation DES uses polymers for drug delivery which are nondegradable in nature and remains attached to stent surface lifetime. Biodegradable polymers have gained immense attention for controlled drug delivery of therapeutic drugs from cardiovascular stents in recent times as nondegradable polymers are associated with long-term adverse events. Studies showed that permanent contact with this polymer creates local inflammatory reactions and long-term stent thrombosis which raises concerns over the widespread use of DES. Biodegradable polymers are widely accepted biomaterials in human health care area and have proved its biocompatibility as drug delivery vehicle in various medicinal applications. This research work is carried out to study mechanisms affecting drug release kinetics from coated cardiovascular stents composed of biodegradable poly lactide-co-caprolactone and polyvinyl pyrrolidone. A conventional air brush technique was effectively modified so that Co-Cr L605 metallic stents were coated within multiple layers having drug Sirolimus blended together with biodegradable polymeric matrix. Kinetic studies for drug dissolution from a stent are carried out in simulated biological fluid using high performance liquid chromatography (HPLC) with simultaneous monitoring of surface morphology by scanning electron microscopy (SEM). Drug elution data analyzed by mathematical models suggested a combination of surface drug dissolution and diffusion as major drug release mechanisms. Investigation of different top coats revealed that drug release is influenced by the hydrophobicity of the drug free protective layer. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425195 Exemplaires
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Titre : Decomposition thermodynamics of magnesium sulfate Type de document : texte imprimé Auteurs : Madeleine N. Scheidema, Auteur ; Pekka Taskinen, Auteur Année de publication : 2011 Article en page(s) : pp. 9550-9556 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Thermodynamics Magnesium Résumé : The stability of MgSO4 was evaluated with varying conditions using HSC Chemistry software and thermo analysis (TG-DSC). The available thermodynamic data were reviewed and the equilibrium calculations using these data were compared to the results of the thermo analysis, in order to select the most reliable data. An enthalpy of formation for MgSO4 of −1284.9 kJ/mol was used in the calculations. Equilibrium calculations of magnesium sulfate in the absence of any reducing agent resulted in a decomposition temperature of 1080 °C. This temperature can be lowered in the presence of a reducing agent, which reduces the energy requirement. The calculations resulted in a decomposition temperature of 625 °C, 600 and 610 °C in the presence of sulfur, carbon monoxide and hydrogen gas as a reducing agent, respectively. The thermo analysis showed that magnesium sulfate decomposed at 1100 °C under N2 atmosphere; at 1070 °C in an atmosphere of 10% CO and 90% N2; and at 950 °C in an atmosphere with 5% H2 and 95% N2. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102554f
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9550-9556[article] Decomposition thermodynamics of magnesium sulfate [texte imprimé] / Madeleine N. Scheidema, Auteur ; Pekka Taskinen, Auteur . - 2011 . - pp. 9550-9556.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9550-9556
Mots-clés : Thermodynamics Magnesium Résumé : The stability of MgSO4 was evaluated with varying conditions using HSC Chemistry software and thermo analysis (TG-DSC). The available thermodynamic data were reviewed and the equilibrium calculations using these data were compared to the results of the thermo analysis, in order to select the most reliable data. An enthalpy of formation for MgSO4 of −1284.9 kJ/mol was used in the calculations. Equilibrium calculations of magnesium sulfate in the absence of any reducing agent resulted in a decomposition temperature of 1080 °C. This temperature can be lowered in the presence of a reducing agent, which reduces the energy requirement. The calculations resulted in a decomposition temperature of 625 °C, 600 and 610 °C in the presence of sulfur, carbon monoxide and hydrogen gas as a reducing agent, respectively. The thermo analysis showed that magnesium sulfate decomposed at 1100 °C under N2 atmosphere; at 1070 °C in an atmosphere of 10% CO and 90% N2; and at 950 °C in an atmosphere with 5% H2 and 95% N2. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102554f Exemplaires
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Titre : Removal mechanisms of toluene from aqueous solutions by chitin and chitosan Type de document : texte imprimé Auteurs : Maryam Mohamed, Auteur ; Sabeha Ouki, Auteur Année de publication : 2011 Article en page(s) : pp. 9557-9563 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Aqueous solution Résumé : Low-cost materials of natural origin such as chitin and chitosan were found to effectively remove toluene from aqueous solutions. Batch adsorption experiments for the removal of toluene (5―200 mg/L) were conducted to obtain the isotherm profile. The effects of various parameters such as initial concentrations, adsorbent dose, and contact time on the removal performance of toluene were evaluated. Chitosan shows better removal efficiency, compared to chitin, both in terms of the level of toluene adsorbed per unit mass of adsorbent and in terms of the adsorption kinetics. Adsorption capacity in the range of 33%―58% efficiency was obtained when the chitosan materials were used. The adsorption data on toluene were found to best fit the Langmuir and Redlich-Peterson isotherm models. The kinetic studies revealed that the adsorption of toluene followed the pseudo-second-order rate model. Overall, the study demonstrated that chitosan is a potential adsorbent for the removal of toluene at concentrations as high as 200 mg/L. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425197
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9557-9563[article] Removal mechanisms of toluene from aqueous solutions by chitin and chitosan [texte imprimé] / Maryam Mohamed, Auteur ; Sabeha Ouki, Auteur . - 2011 . - pp. 9557-9563.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9557-9563
Mots-clés : Aqueous solution Résumé : Low-cost materials of natural origin such as chitin and chitosan were found to effectively remove toluene from aqueous solutions. Batch adsorption experiments for the removal of toluene (5―200 mg/L) were conducted to obtain the isotherm profile. The effects of various parameters such as initial concentrations, adsorbent dose, and contact time on the removal performance of toluene were evaluated. Chitosan shows better removal efficiency, compared to chitin, both in terms of the level of toluene adsorbed per unit mass of adsorbent and in terms of the adsorption kinetics. Adsorption capacity in the range of 33%―58% efficiency was obtained when the chitosan materials were used. The adsorption data on toluene were found to best fit the Langmuir and Redlich-Peterson isotherm models. The kinetic studies revealed that the adsorption of toluene followed the pseudo-second-order rate model. Overall, the study demonstrated that chitosan is a potential adsorbent for the removal of toluene at concentrations as high as 200 mg/L. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425197 Exemplaires
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Titre : Evaluation of the capacity of hydroxyapaptite prepared from concrete sludge to remove lead from water Type de document : texte imprimé Auteurs : Takeshi Sasaki, Auteur ; Yuka Sakai, Auteur ; Atsushi Iizuka, Auteur Année de publication : 2011 Article en page(s) : pp. 9564-9568 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydroxyapaptite Résumé : Low-crystallinity hydroxyapatite (HAP) was prepared from concrete sludge as a recycling method for concrete waste. The HAP was prepared from model samples of concrete sludge and phosphorus wastewater, and its capacity to remove lead from water was investigated. Lead ions were quickly removed by the HAP particles. Some of the prepared HAP samples reduced the lead concentration of the water to within the Japanese standard for industrial effluent (0.1 ppm). The lead removal capacity of the concrete sludge-derived HAP (506 mg/g) was comparable to that of reagent grade HAP. Lead in water was removed in the form of Pb3(CO3)2(OH)2. These results indicate that HAP prepared from concrete sludge can be applied to removal of lead ions from water. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200233s
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9564-9568[article] Evaluation of the capacity of hydroxyapaptite prepared from concrete sludge to remove lead from water [texte imprimé] / Takeshi Sasaki, Auteur ; Yuka Sakai, Auteur ; Atsushi Iizuka, Auteur . - 2011 . - pp. 9564-9568.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9564-9568
Mots-clés : Hydroxyapaptite Résumé : Low-crystallinity hydroxyapatite (HAP) was prepared from concrete sludge as a recycling method for concrete waste. The HAP was prepared from model samples of concrete sludge and phosphorus wastewater, and its capacity to remove lead from water was investigated. Lead ions were quickly removed by the HAP particles. Some of the prepared HAP samples reduced the lead concentration of the water to within the Japanese standard for industrial effluent (0.1 ppm). The lead removal capacity of the concrete sludge-derived HAP (506 mg/g) was comparable to that of reagent grade HAP. Lead in water was removed in the form of Pb3(CO3)2(OH)2. These results indicate that HAP prepared from concrete sludge can be applied to removal of lead ions from water. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200233s Exemplaires
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Titre : Removal of N-methyl-2-pyrrolidone by photocatalytic degradation in a batch reactor Type de document : texte imprimé Auteurs : Alireza Zolfaghari, Auteur ; Hamid Reza Mortaheb, Auteur ; Fatemeh Meshkini, Auteur Année de publication : 2011 Article en page(s) : pp. 9569-9576 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Reactor Batchwise Photochemical degradation Résumé : Photocatalytic degradation of N-methyl-2-pyrrolidone (NMP) was investigated in an aerated UV/TiO2 batch system. The effects of TiO2 photocatalyst loading, temperature, pH, initial concentration, and the type of gas phase on the reaction rate were ascertained, and the optimum conditions for the maximum degradation rate were determined. The results showed that photocatalytic degradation ofNMP is strongly influenced by these parameters. The optimum TiO2 loading, which provides enough surface area for reaction without irradiation loss due to scattering of UV light, was found to be 0.1 wt %. It was revealed that due to bilateral effect of temperature on the process, the maximum oxidation rate (0.22 min―1) is obtained at 45 °C. The highest photodegradation reaction rate is obtained in neutral or slightly acidic condition rather than in extreme acidic or alkaline range. The pseudo-first-order reaction rate expression based on Langmuir―Hinshelwood model can reasonably simulate the photocatalytic degradation process. The optimum values for TiO2 photocatalyst loading, temperature, and pH were confirmed by economic factor analysis based on electrical energy consumption. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425199
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9569-9576[article] Removal of N-methyl-2-pyrrolidone by photocatalytic degradation in a batch reactor [texte imprimé] / Alireza Zolfaghari, Auteur ; Hamid Reza Mortaheb, Auteur ; Fatemeh Meshkini, Auteur . - 2011 . - pp. 9569-9576.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9569-9576
Mots-clés : Reactor Batchwise Photochemical degradation Résumé : Photocatalytic degradation of N-methyl-2-pyrrolidone (NMP) was investigated in an aerated UV/TiO2 batch system. The effects of TiO2 photocatalyst loading, temperature, pH, initial concentration, and the type of gas phase on the reaction rate were ascertained, and the optimum conditions for the maximum degradation rate were determined. The results showed that photocatalytic degradation ofNMP is strongly influenced by these parameters. The optimum TiO2 loading, which provides enough surface area for reaction without irradiation loss due to scattering of UV light, was found to be 0.1 wt %. It was revealed that due to bilateral effect of temperature on the process, the maximum oxidation rate (0.22 min―1) is obtained at 45 °C. The highest photodegradation reaction rate is obtained in neutral or slightly acidic condition rather than in extreme acidic or alkaline range. The pseudo-first-order reaction rate expression based on Langmuir―Hinshelwood model can reasonably simulate the photocatalytic degradation process. The optimum values for TiO2 photocatalyst loading, temperature, and pH were confirmed by economic factor analysis based on electrical energy consumption. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425199 Exemplaires
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Titre : Kinetic modeling of hydroxycarbonylation of styrene using a homogeneous palladium complex catalyst Type de document : texte imprimé Auteurs : Yuanchun Li, Auteur ; Raghunath V. Chaudhari, Auteur Année de publication : 2011 Article en page(s) : pp. 9577-9586 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Modeling Catalyst Kinetic model Résumé : Kinetics of hydrorycarbonylation of styrene using Pd(pyca)(PPh3)(OTs)/PPh3/TsOH/LiCl catalyst was investigated in a stirred batch reactor. The effects of catalyst, styrene, and water concentrations and the partial pressure of CO on the rate of hydroxycarbonylation as well as the concentration—time profiles have been investigated over a temperature range of 368-388 K. A unique observation was the induction period which was CO pressure dependent leading to lower rates of carbonylation at the start of the reaction. A molecular level description of the reaction mechanism (catalytic cycle) has been proposed to explain the observed trends. The results were found to be consistent with a mechanism based on a Pd-hydride complex as an active intermediate species. The proposed mechanism also captured the experimentally observed trends of induction period. The approach of microkinetic modeling used here does not require the assumption of a rate determining step and provides a good description of the complex trends observed with respect to reaction parameters over a wide range of conditions. Note de contenu : http://atcatalogue_2.enp.edu.dz/catalog.php?categ=serials&sub=analysis&action=analysis_form&bul_id=15578&analysis_id=0 DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425200
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9577-9586[article] Kinetic modeling of hydroxycarbonylation of styrene using a homogeneous palladium complex catalyst [texte imprimé] / Yuanchun Li, Auteur ; Raghunath V. Chaudhari, Auteur . - 2011 . - pp. 9577-9586.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9577-9586
Mots-clés : Modeling Catalyst Kinetic model Résumé : Kinetics of hydrorycarbonylation of styrene using Pd(pyca)(PPh3)(OTs)/PPh3/TsOH/LiCl catalyst was investigated in a stirred batch reactor. The effects of catalyst, styrene, and water concentrations and the partial pressure of CO on the rate of hydroxycarbonylation as well as the concentration—time profiles have been investigated over a temperature range of 368-388 K. A unique observation was the induction period which was CO pressure dependent leading to lower rates of carbonylation at the start of the reaction. A molecular level description of the reaction mechanism (catalytic cycle) has been proposed to explain the observed trends. The results were found to be consistent with a mechanism based on a Pd-hydride complex as an active intermediate species. The proposed mechanism also captured the experimentally observed trends of induction period. The approach of microkinetic modeling used here does not require the assumption of a rate determining step and provides a good description of the complex trends observed with respect to reaction parameters over a wide range of conditions. Note de contenu : http://atcatalogue_2.enp.edu.dz/catalog.php?categ=serials&sub=analysis&action=analysis_form&bul_id=15578&analysis_id=0 DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425200 Exemplaires
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Titre : Synthesis of stainless-steel-net supported TS-1 catalyst and Its catalytic performance in liquid-phase epoxidation reactions Type de document : texte imprimé Auteurs : Yuting Zheng, Auteur ; Yingtian Zhang, Auteur ; Zhendong Wang, Auteur Année de publication : 2011 Article en page(s) : pp. 9587-9593 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Epoxidation Liquid phase Catalytic reaction Catalyst Stainless steel Résumé : TS-1 particles were loaded on stainless-steel-net (SSN) to form an integrated material (TS-1/SSN) by secondary hydrothermal synthesis. This avoided completely the filtration separation in both catalyst preparation and catalytic applications in liquid-phase reactions. Seeding-assisted secondary crystallization prevented zeolite from detaching from the support during the synthesis process. The TS-1 particles were coated on the SSN support uniformly, and their loading amount was adjustable in the range of 7―25 wt % by repeating the seeding and crystallization processes. UV―visible and IR spectra verified that the titanium species in TS-1/SSN mostly occupied the tetrahedral coordination sites in the zeolite framework. TS-1/SSN was comparably active to conventional TS-1 particles in batchwise epoxidation of 1-hexene with H2O2. The zeolite particles maintained the catalytic activity and did not detach from the SSN after five reuses. Moreover, TS-I/SSN proved to be efficient and reusable in continuous epoxidation of allyl chloride where the separation of products and catalyst occurred easily. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425201
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9587-9593[article] Synthesis of stainless-steel-net supported TS-1 catalyst and Its catalytic performance in liquid-phase epoxidation reactions [texte imprimé] / Yuting Zheng, Auteur ; Yingtian Zhang, Auteur ; Zhendong Wang, Auteur . - 2011 . - pp. 9587-9593.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9587-9593
Mots-clés : Epoxidation Liquid phase Catalytic reaction Catalyst Stainless steel Résumé : TS-1 particles were loaded on stainless-steel-net (SSN) to form an integrated material (TS-1/SSN) by secondary hydrothermal synthesis. This avoided completely the filtration separation in both catalyst preparation and catalytic applications in liquid-phase reactions. Seeding-assisted secondary crystallization prevented zeolite from detaching from the support during the synthesis process. The TS-1 particles were coated on the SSN support uniformly, and their loading amount was adjustable in the range of 7―25 wt % by repeating the seeding and crystallization processes. UV―visible and IR spectra verified that the titanium species in TS-1/SSN mostly occupied the tetrahedral coordination sites in the zeolite framework. TS-1/SSN was comparably active to conventional TS-1 particles in batchwise epoxidation of 1-hexene with H2O2. The zeolite particles maintained the catalytic activity and did not detach from the SSN after five reuses. Moreover, TS-I/SSN proved to be efficient and reusable in continuous epoxidation of allyl chloride where the separation of products and catalyst occurred easily. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425201 Exemplaires
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Titre : CuO Nanoparticles : a simple, effective, ligand free, and reusable heterogeneous catalyst for N-arylation of benzimidazole Type de document : texte imprimé Auteurs : Sundaram Ganesh Babu, Auteur ; Ramasamy Karvembu, Auteur Année de publication : 2011 Article en page(s) : pp. 9594-9600 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Heterogeneous catalysis Ligand Nanoparticle Résumé : Copper(II) oxide (CuO) nanoparticles have been synthesized from copper acetate by simple precipitation method and were found to be an efficient and inexpensive catalyst for C―N cross-coupling reactions of benzimidazole with various aryl halides. The catalyst was characterized by scanning electron microscope, transmission electron microscope, Brunauer―Emmett―Teller—surface area, and X-ray diffraction analysis. Benzimidazole undergoes reaction with aryl bromides, aryl chlorides, or aryl fluorides in the presence of K2CO3 at moderate temperature. The yield of N-arylated benzimidazole is ranging from 55 to 92%. The effect of the particle size of the catalyst on N-arylation of benzimidazole with 4-chlorobenzonitrile was studied. Reusability of the CuO nanoparticles was also carried out, and the results were found to be good. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425202
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9594-9600[article] CuO Nanoparticles : a simple, effective, ligand free, and reusable heterogeneous catalyst for N-arylation of benzimidazole [texte imprimé] / Sundaram Ganesh Babu, Auteur ; Ramasamy Karvembu, Auteur . - 2011 . - pp. 9594-9600.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9594-9600
Mots-clés : Heterogeneous catalysis Ligand Nanoparticle Résumé : Copper(II) oxide (CuO) nanoparticles have been synthesized from copper acetate by simple precipitation method and were found to be an efficient and inexpensive catalyst for C―N cross-coupling reactions of benzimidazole with various aryl halides. The catalyst was characterized by scanning electron microscope, transmission electron microscope, Brunauer―Emmett―Teller—surface area, and X-ray diffraction analysis. Benzimidazole undergoes reaction with aryl bromides, aryl chlorides, or aryl fluorides in the presence of K2CO3 at moderate temperature. The yield of N-arylated benzimidazole is ranging from 55 to 92%. The effect of the particle size of the catalyst on N-arylation of benzimidazole with 4-chlorobenzonitrile was studied. Reusability of the CuO nanoparticles was also carried out, and the results were found to be good. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425202 Exemplaires
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Titre : Intensification of degradation of 2,4,6-trichlorophenol using sonochemical reactors : understanding mechanism and scale-up aspects Type de document : texte imprimé Auteurs : Akshaykumar K. Shriwas, Auteur ; Parag R. Gogate, Auteur Année de publication : 2011 Article en page(s) : pp. 9601-9608 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Scale effect Extrapolation Reactor Sonochemical reaction Résumé : Degradation of 2,4,6-trichlorophenol (TCP) has been investigated using two types of sonochemical reactors viz. ultrasonic horn and ultrasonic bath reactors with an objective of investigating the effect of different operating parameters and intensifying the extent of degradation using different additives. Effect of different operating parameters such as operating temperature, power input, operating pH, and use of different additives such as solid particles, air, and hydrogen peroxide has been investigated. Experiments have been performed at two different scales of operation with an objective of illustrating the guidelines for possible scale-up strategies for cost-effective operation. As the extent of degradation was significantly lower in large scale reactor, intensification studies have been carried out by combining sonication with UV light and ozone. Possible mechanisms for intensification due to the use of different additives and combining oxidation techniques have also been illustrated based on the observed results. Maximum degradation has been obtained in the presence of air in the horn type reactor and in the presence of TiO2 as catalyst in larger capacity reactor. It has been observed that the use of additives which enhance the overall cavitational activity is more recommended due to the dominant pyrolytic mechanism of degradation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425203
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9601-9608[article] Intensification of degradation of 2,4,6-trichlorophenol using sonochemical reactors : understanding mechanism and scale-up aspects [texte imprimé] / Akshaykumar K. Shriwas, Auteur ; Parag R. Gogate, Auteur . - 2011 . - pp. 9601-9608.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9601-9608
Mots-clés : Scale effect Extrapolation Reactor Sonochemical reaction Résumé : Degradation of 2,4,6-trichlorophenol (TCP) has been investigated using two types of sonochemical reactors viz. ultrasonic horn and ultrasonic bath reactors with an objective of investigating the effect of different operating parameters and intensifying the extent of degradation using different additives. Effect of different operating parameters such as operating temperature, power input, operating pH, and use of different additives such as solid particles, air, and hydrogen peroxide has been investigated. Experiments have been performed at two different scales of operation with an objective of illustrating the guidelines for possible scale-up strategies for cost-effective operation. As the extent of degradation was significantly lower in large scale reactor, intensification studies have been carried out by combining sonication with UV light and ozone. Possible mechanisms for intensification due to the use of different additives and combining oxidation techniques have also been illustrated based on the observed results. Maximum degradation has been obtained in the presence of air in the horn type reactor and in the presence of TiO2 as catalyst in larger capacity reactor. It has been observed that the use of additives which enhance the overall cavitational activity is more recommended due to the dominant pyrolytic mechanism of degradation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425203 Exemplaires
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Titre : Kinetics study of 3-methylthiophene alkylation with isobutylene catalyzed by NKC-9 ion exchange resin Type de document : texte imprimé Auteurs : Yu Liu, Auteur ; Bolun Yang, Auteur ; Chunhai Yi, Auteur Année de publication : 2011 Article en page(s) : pp. 9609-9616 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ion exchange resin Catalytic reaction Alkylation Kinetics Résumé : A series of experiments were carried out in a stirred batch reactor at the temperature range of 333-363 K and the pressure of 1.5—2.5 MPa by using NKC-9 ion-exchange resin to investigate the alkylation kinetics of 3-methylthiophene (3MT) with isobutylene (IB). The effect of various operation parameters such as stirring speed, catalyst particle size, temperature, pressure, and sulfur content on the conversion and selectivity of alkylation reaction were studied. Experimental results indicated that the alkylation of 3MT with IB was followed by a parallel reaction of IB oligomerization; higher temperature could improve the alkylation activity while lower temperature was profitable to the reaction selectivity over the NKC-9 catalyst; however, the operating pressure has little effect on the alkylation and oligomerization; much sulfur content could inhibit IB dimerization. The Eley-Rideal (ER) law can be used to explain the reaction mechanism, and the kinetics models that considered the alkylation and oligomerization at the same time were established. Kinetics parameters were solved, and the calculation results agreed well with the experimental results. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425204
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9609-9616[article] Kinetics study of 3-methylthiophene alkylation with isobutylene catalyzed by NKC-9 ion exchange resin [texte imprimé] / Yu Liu, Auteur ; Bolun Yang, Auteur ; Chunhai Yi, Auteur . - 2011 . - pp. 9609-9616.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9609-9616
Mots-clés : Ion exchange resin Catalytic reaction Alkylation Kinetics Résumé : A series of experiments were carried out in a stirred batch reactor at the temperature range of 333-363 K and the pressure of 1.5—2.5 MPa by using NKC-9 ion-exchange resin to investigate the alkylation kinetics of 3-methylthiophene (3MT) with isobutylene (IB). The effect of various operation parameters such as stirring speed, catalyst particle size, temperature, pressure, and sulfur content on the conversion and selectivity of alkylation reaction were studied. Experimental results indicated that the alkylation of 3MT with IB was followed by a parallel reaction of IB oligomerization; higher temperature could improve the alkylation activity while lower temperature was profitable to the reaction selectivity over the NKC-9 catalyst; however, the operating pressure has little effect on the alkylation and oligomerization; much sulfur content could inhibit IB dimerization. The Eley-Rideal (ER) law can be used to explain the reaction mechanism, and the kinetics models that considered the alkylation and oligomerization at the same time were established. Kinetics parameters were solved, and the calculation results agreed well with the experimental results. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425204 Exemplaires
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Titre : Preparation and characterization of sulfonated copolyamides based on poly(hexafluoroisopropylidene) isophthalamides for polymer electrolytic membranes Type de document : texte imprimé Auteurs : Yamile Perez-Padilla, Auteur ; Mascha. A. Smit, Auteur ; Manuel J. Aguilar-Vega, Auteur Année de publication : 2011 Article en page(s) : pp. 9617-9624 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Preparation Polymer electrolytic membranes Résumé : A series of sulfonated random copolyamides with increasing sulfonation degree were synthesized from the aromatic diamine 4,4'-(hexafluoroisopropylidene)dianiline, HFA, reacted with 2,4-diaminobenzenosulfonic acid, DABS, by direct polycondensation using isophthalic diacid, ISO, as comonomer. Thin films of the sulfonated copolyamides were prepared by the solution-evaporation method using dimethylacetamide, DMAc. The structure of the resulting sulfonated copolyamides was confirmed by FTIR and 1H NMR which evidenced the presence of amide and sulfonic groups in the proposed concentrations. Thermal stabilities as characterized by TGA, showed the onset of decomposition at 320 °C for the ionic moieties and above 600 °C for the nonsulfonated part of the copolymers. The values of water uptake and ion exchange capacity, IEC, at room temperature for the copolymer with 50 mol % of DABS, HFAS55 membrane were higher than those obtained for Nafion 115. HFAS55 also presented a proton conductivity value of 3.3 (mS cm―1) which was similar to the one of Nafion 115 tested under the same conditions which situates it as a possible material for PEM membrane preparation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425205
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9617-9624[article] Preparation and characterization of sulfonated copolyamides based on poly(hexafluoroisopropylidene) isophthalamides for polymer electrolytic membranes [texte imprimé] / Yamile Perez-Padilla, Auteur ; Mascha. A. Smit, Auteur ; Manuel J. Aguilar-Vega, Auteur . - 2011 . - pp. 9617-9624.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9617-9624
Mots-clés : Preparation Polymer electrolytic membranes Résumé : A series of sulfonated random copolyamides with increasing sulfonation degree were synthesized from the aromatic diamine 4,4'-(hexafluoroisopropylidene)dianiline, HFA, reacted with 2,4-diaminobenzenosulfonic acid, DABS, by direct polycondensation using isophthalic diacid, ISO, as comonomer. Thin films of the sulfonated copolyamides were prepared by the solution-evaporation method using dimethylacetamide, DMAc. The structure of the resulting sulfonated copolyamides was confirmed by FTIR and 1H NMR which evidenced the presence of amide and sulfonic groups in the proposed concentrations. Thermal stabilities as characterized by TGA, showed the onset of decomposition at 320 °C for the ionic moieties and above 600 °C for the nonsulfonated part of the copolymers. The values of water uptake and ion exchange capacity, IEC, at room temperature for the copolymer with 50 mol % of DABS, HFAS55 membrane were higher than those obtained for Nafion 115. HFAS55 also presented a proton conductivity value of 3.3 (mS cm―1) which was similar to the one of Nafion 115 tested under the same conditions which situates it as a possible material for PEM membrane preparation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425205 Exemplaires
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Titre : Continuous Hydrothermal Synthesis of Nickel Ferrite Nanoparticles Using a Central Collision-Type Micromixer : effects of temperature, residence time, metal salt molality, and NaOH addition on conversion, particle size, and crystal phase Type de document : texte imprimé Auteurs : Kiwamu Sue, Auteur ; Mitsuko Aoki, Auteur ; Takafumi Sato, Auteur Année de publication : 2011 Article en page(s) : pp. 9625-9631 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Particle size Temperature effect Micromixing Collision Nanoparticle Résumé : Continuous hydrothermal synthesis of nickel ferrite nanopartides from Fe(NO3)3 and Ni(NO3)2 was performed using a central collision-type micromixer developed for rapid heating of a starting solution to the reaction temperature and homogeneous nucleation. Temperature, residence time, and nitrate molality were varied in the ranges 573―673 K, 0.02―2.00 s, and 0.05―0.50 mol/kg, respectively. The effects of temperature, residence time, nitrate molality, and NaOH addition on conversion, Ni/Fe molar ratio, particle size, and crystal phase were examined using ICP spectroscopy, EDX spectroscopy, TEM, and XRD. In the cases without NaOH, the Ni conversion was less than 2% at temperatures up to 623 K and increased dramatically to around 50% at 673 K, whereas the Fe conversion was more than 94% at all temperatures. In terms of conversion, the Ni/Fe molar ratio was less than 0.01 at temperatures up to 623 K, and stable nickel ferrite was not produced. By contrast, at 673 K, the Ni/Fe molar ratio increased sharply to more than 0.2, and stable nickel ferrite could be obtained. With increasing residence time at 673 K, the Ni conversion and Ni/Fe ratio increased, and the lattice parameter decreased from 8.35 to 8.34 Å. These results indicate that the products at an early stage of the reaction are similar in structure to γ-Fe2O3 and can be considered as a Ni-deficient NiFe2O4 whereas the products at a later stage have a structure dose to that of NiFe2O4. In addition, the average particle size increased slightly from 5.2 to 7.4 nm at 0.05 mol/kg and increased markedly from 5.8 to 12.3 nm at 0.50 mol/kg with increasing temperature despite the high Fe conversion of >97% at the shortest residence time of 0.02 s. In the cases with NaOH, smaller nanoparticles of less than 5.0 nm with a stoichiometric Ni/Fe molar ratio of 0.5 were produced at 673 K. On the basis of these results, the mechanisms of nucleation and growth in the nickel ferrite synthesis are discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425206
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9625-9631[article] Continuous Hydrothermal Synthesis of Nickel Ferrite Nanoparticles Using a Central Collision-Type Micromixer : effects of temperature, residence time, metal salt molality, and NaOH addition on conversion, particle size, and crystal phase [texte imprimé] / Kiwamu Sue, Auteur ; Mitsuko Aoki, Auteur ; Takafumi Sato, Auteur . - 2011 . - pp. 9625-9631.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9625-9631
Mots-clés : Particle size Temperature effect Micromixing Collision Nanoparticle Résumé : Continuous hydrothermal synthesis of nickel ferrite nanopartides from Fe(NO3)3 and Ni(NO3)2 was performed using a central collision-type micromixer developed for rapid heating of a starting solution to the reaction temperature and homogeneous nucleation. Temperature, residence time, and nitrate molality were varied in the ranges 573―673 K, 0.02―2.00 s, and 0.05―0.50 mol/kg, respectively. The effects of temperature, residence time, nitrate molality, and NaOH addition on conversion, Ni/Fe molar ratio, particle size, and crystal phase were examined using ICP spectroscopy, EDX spectroscopy, TEM, and XRD. In the cases without NaOH, the Ni conversion was less than 2% at temperatures up to 623 K and increased dramatically to around 50% at 673 K, whereas the Fe conversion was more than 94% at all temperatures. In terms of conversion, the Ni/Fe molar ratio was less than 0.01 at temperatures up to 623 K, and stable nickel ferrite was not produced. By contrast, at 673 K, the Ni/Fe molar ratio increased sharply to more than 0.2, and stable nickel ferrite could be obtained. With increasing residence time at 673 K, the Ni conversion and Ni/Fe ratio increased, and the lattice parameter decreased from 8.35 to 8.34 Å. These results indicate that the products at an early stage of the reaction are similar in structure to γ-Fe2O3 and can be considered as a Ni-deficient NiFe2O4 whereas the products at a later stage have a structure dose to that of NiFe2O4. In addition, the average particle size increased slightly from 5.2 to 7.4 nm at 0.05 mol/kg and increased markedly from 5.8 to 12.3 nm at 0.50 mol/kg with increasing temperature despite the high Fe conversion of >97% at the shortest residence time of 0.02 s. In the cases with NaOH, smaller nanoparticles of less than 5.0 nm with a stoichiometric Ni/Fe molar ratio of 0.5 were produced at 673 K. On the basis of these results, the mechanisms of nucleation and growth in the nickel ferrite synthesis are discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425206 Exemplaires
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Titre : Carbon dioxide induced crystallization for toughening polypropylene Type de document : texte imprimé Auteurs : Jin-Biao Bao, Auteur ; Tao Liu, Auteur ; Ling Zhao, Auteur Année de publication : 2011 Article en page(s) : pp. 9632-9641 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Crystallization Carbon dioxide Résumé : This study proposes a novel process for significantly toughening isotactic polypropylene (iPP) by finely tuning and controlling the structure and morphology ofiPP. The toughness of injection-molded iPP specimens can be significantly improved by controlled shearing, CO2-induced recrystallization, and adequate cooling without loss of strength. The distribution and structure of the iPP samples before and after toughening were characterized by polarized optical microscopy, Fourier transform infrared spectroscopy, wide-angle X-ray diffraction, small-angle X-ray scattering, scanning electron microscopy, and differential scanning calorimetry, to investigate the structure―property relationship. Under shear, a high degree of orientation can be obtained with "shish-kebab" crystals formed in the shear zone. During the subsequent CO2 treatment, a crystal network morphology can be formed as a result of an increase in the numbers of primary lamellae and crosshatched subsidiary lamellae, which leads to an increase in toughness. Wide-angle X-ray diffraction patterns indicate that quenching in ice-water of scCO2-treated iPP promotes the formation of nanosized mesomorphic phase domains in the shear zone, which further toughens the iPP. The impact strength of the best toughened iPP sample was found to be over 12 times that of the original sample without loss in tensile strength and modulus. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425207
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9632-9641[article] Carbon dioxide induced crystallization for toughening polypropylene [texte imprimé] / Jin-Biao Bao, Auteur ; Tao Liu, Auteur ; Ling Zhao, Auteur . - 2011 . - pp. 9632-9641.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9632-9641
Mots-clés : Crystallization Carbon dioxide Résumé : This study proposes a novel process for significantly toughening isotactic polypropylene (iPP) by finely tuning and controlling the structure and morphology ofiPP. The toughness of injection-molded iPP specimens can be significantly improved by controlled shearing, CO2-induced recrystallization, and adequate cooling without loss of strength. The distribution and structure of the iPP samples before and after toughening were characterized by polarized optical microscopy, Fourier transform infrared spectroscopy, wide-angle X-ray diffraction, small-angle X-ray scattering, scanning electron microscopy, and differential scanning calorimetry, to investigate the structure―property relationship. Under shear, a high degree of orientation can be obtained with "shish-kebab" crystals formed in the shear zone. During the subsequent CO2 treatment, a crystal network morphology can be formed as a result of an increase in the numbers of primary lamellae and crosshatched subsidiary lamellae, which leads to an increase in toughness. Wide-angle X-ray diffraction patterns indicate that quenching in ice-water of scCO2-treated iPP promotes the formation of nanosized mesomorphic phase domains in the shear zone, which further toughens the iPP. The impact strength of the best toughened iPP sample was found to be over 12 times that of the original sample without loss in tensile strength and modulus. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425207 Exemplaires
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Titre : Role of surface chemistry and energetics in high shear wet granulation Type de document : texte imprimé Auteurs : Raimundo Ho, Auteur ; Sarah E. Dilworth, Auteur ; Daryl R. Williams, Auteur Année de publication : 2011 Article en page(s) : pp. 9642–9649 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Surface chemistry Energetics Résumé : This article presents a detailed study of the role of solid state surface chemistry on the high shear granulation performance of organic pharmaceutical solids. The sole effect of powder surface chemistry on granulation performance was investigated by coagglomerating untreated and silanized d-mannitol powder from a narrow sieve fraction in a high shear process. The wetting performance by polyvinylpyrrolidone (PVP) binder solutions was quantified using experimentally determined thermodynamic spreading coefficients, calculated from surface energy heterogeneity distributions obtained via inverse gas chromatography (IGC) measurements. Increases in binder wettability of the formulations correlated with increases in both granule size and compressive elastic moduli, which are attributed to an increase in interparticle contacts. In conclusion, starting materials surface chemistry plays a crucial role in final granule properties, even in highly agitated processes such as high shear granulation. The comprehensive characterization of powder surface properties is necessary to facilitate the manufacture of granules with controllable critical attributes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2009263
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9642–9649[article] Role of surface chemistry and energetics in high shear wet granulation [texte imprimé] / Raimundo Ho, Auteur ; Sarah E. Dilworth, Auteur ; Daryl R. Williams, Auteur . - 2011 . - pp. 9642–9649.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9642–9649
Mots-clés : Surface chemistry Energetics Résumé : This article presents a detailed study of the role of solid state surface chemistry on the high shear granulation performance of organic pharmaceutical solids. The sole effect of powder surface chemistry on granulation performance was investigated by coagglomerating untreated and silanized d-mannitol powder from a narrow sieve fraction in a high shear process. The wetting performance by polyvinylpyrrolidone (PVP) binder solutions was quantified using experimentally determined thermodynamic spreading coefficients, calculated from surface energy heterogeneity distributions obtained via inverse gas chromatography (IGC) measurements. Increases in binder wettability of the formulations correlated with increases in both granule size and compressive elastic moduli, which are attributed to an increase in interparticle contacts. In conclusion, starting materials surface chemistry plays a crucial role in final granule properties, even in highly agitated processes such as high shear granulation. The comprehensive characterization of powder surface properties is necessary to facilitate the manufacture of granules with controllable critical attributes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2009263 Exemplaires
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Titre : Elemental mercury capture from flue gas by magnetic Mn–Fe spinel : effect of chemical heterogeneity Type de document : texte imprimé Auteurs : Shijian Yang, Auteur ; Yongfu Guo, Auteur ; Naiqiang Yan, Auteur Année de publication : 2011 Article en page(s) : pp. 9650-9656 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Heterogeneity Gaseous effluent Zerovalent metal Résumé : A stoichiometric nanosized Mn―Fe spinel (Fe2.2Mno0.8O4) was synthesized using a coprecipitation method. After the thermal treatment at 400 °C under air, chemical heterogeneity deriving from the oxidation kinetic difference between Fe2+ and Mn2+/Mn3+ was observed in (Fe2.2Mn0.8)1-δO4. XPS and TEM analyses both pointed a Mn enrichment (especially Mn4+ cation) on the particle's surface. Furthermore, the percent of cation vacancy on the surface increased obviously due to the enrichment of Mn4+ cation on the surface. As a result, the capacity of (Fe2.2Mn0.8)1-δ-400 for elemental mercury capture was generally much better than those of MnOx/γ-Fe2O3, (Fe2.2Mn0.8)1-δO4-200 and Fe2.2Mn0.8O4. Furthermore, the saturation magnetization of (Fe2.2Mn0.8)1-δO4 obviously increased after the thermal treatment under air at 400 °C, which made it easier to separate the sorbent and adsorbed mercury from the fly ash for recycling, regeneration, and safe disposal of the adsorbed mercury. Therefore, (Fe2.2Mn0.8)1-δO4-400 may be a promising sorbent for elemental mercury capture. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425209
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9650-9656[article] Elemental mercury capture from flue gas by magnetic Mn–Fe spinel : effect of chemical heterogeneity [texte imprimé] / Shijian Yang, Auteur ; Yongfu Guo, Auteur ; Naiqiang Yan, Auteur . - 2011 . - pp. 9650-9656.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9650-9656
Mots-clés : Heterogeneity Gaseous effluent Zerovalent metal Résumé : A stoichiometric nanosized Mn―Fe spinel (Fe2.2Mno0.8O4) was synthesized using a coprecipitation method. After the thermal treatment at 400 °C under air, chemical heterogeneity deriving from the oxidation kinetic difference between Fe2+ and Mn2+/Mn3+ was observed in (Fe2.2Mn0.8)1-δO4. XPS and TEM analyses both pointed a Mn enrichment (especially Mn4+ cation) on the particle's surface. Furthermore, the percent of cation vacancy on the surface increased obviously due to the enrichment of Mn4+ cation on the surface. As a result, the capacity of (Fe2.2Mn0.8)1-δ-400 for elemental mercury capture was generally much better than those of MnOx/γ-Fe2O3, (Fe2.2Mn0.8)1-δO4-200 and Fe2.2Mn0.8O4. Furthermore, the saturation magnetization of (Fe2.2Mn0.8)1-δO4 obviously increased after the thermal treatment under air at 400 °C, which made it easier to separate the sorbent and adsorbed mercury from the fly ash for recycling, regeneration, and safe disposal of the adsorbed mercury. Therefore, (Fe2.2Mn0.8)1-δO4-400 may be a promising sorbent for elemental mercury capture. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425209 Exemplaires
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Titre : Extending ideal PID tuning rules to the ISA real structure : two procedures and a benchmark campaign Type de document : texte imprimé Auteurs : Martina Maggio, Auteur ; Alberto Leva, Auteur Année de publication : 2011 Article en page(s) : pp. 9657-9666 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Benchmarks Résumé : Although virtually any installed PID controller encompasses a derivative filter, and very frequently takes the standard ISA form, many tuning rules refer to the ideal controller structure, which is subsequently made realizable by introducing the so-called "derivative filter" a posteriori. Doing so can sometimes lead to undesired results. This paper investigates the matter and discusses two very simple but rigorous procedures to extend ideal PID tuning rules to the ISA controller. A benchmark simulation campaign, referring to several well-assessed rules, demonstrates the opportunity and efficacy of the proposed extensions. A quite realistic test referring to a typical process control case is also presented. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425210
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9657-9666[article] Extending ideal PID tuning rules to the ISA real structure : two procedures and a benchmark campaign [texte imprimé] / Martina Maggio, Auteur ; Alberto Leva, Auteur . - 2011 . - pp. 9657-9666.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9657-9666
Mots-clés : Benchmarks Résumé : Although virtually any installed PID controller encompasses a derivative filter, and very frequently takes the standard ISA form, many tuning rules refer to the ideal controller structure, which is subsequently made realizable by introducing the so-called "derivative filter" a posteriori. Doing so can sometimes lead to undesired results. This paper investigates the matter and discusses two very simple but rigorous procedures to extend ideal PID tuning rules to the ISA controller. A benchmark simulation campaign, referring to several well-assessed rules, demonstrates the opportunity and efficacy of the proposed extensions. A quite realistic test referring to a typical process control case is also presented. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425210 Exemplaires
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Titre : Integration of renewable energy with industrial absorption refrigeration systems : systematic design and operation with technical, economic, and environmental objectives Type de document : texte imprimé Auteurs : José María Ponce-Ortega, Auteur ; Eman A. Tora, Auteur ; J. Betzabe Gonzalez-Campos, Auteur Année de publication : 2011 Article en page(s) : pp. 9667–9684 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Design Refrigeration Résumé : This paper presents a new methodology for the energy integration of systems that require refrigeration. It considers the integration between process streams as well as that between the heat from process stream excess, solar energy, fossil fuels, and biofuels to run the stripper required by the absorption refrigeration (AR) needed. The proposed methodology consists of two stages: the first one identifies the energy targets, while the second one uses a new mathematical programming model to solve a multiobjective optimization mixed-integer linear programming (MILP) problem, allowing one to determine the minimum cost as well as the minimum greenhouse gas emissions (GHGE) to satisfy the utility requirements identified in the first stage. The proposed model considers the optimal selection of different types of solar collectors, and since the solar radiation depends on the season of the year, the model also accounts for the best combination of fossil and biofuels to complement the energy required for the AR. The proposed methodology is very useful to identify the scenario required to implement the use of clean energies in the refrigeration process. Three problems are presented to show the applicability of the proposed methodology, which does not exhibit numerical complications; these results show that process integration helps to get a given reduction in the GHGE economically attractive involving the use of dean energies, besides identifying the required tax credit to get economic and environmentally efficient cooling systems. In addition, because of the availability of the solar radiation, the solar collectors must be integrated with different types of energy, depending on the season of the year. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425211
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9667–9684[article] Integration of renewable energy with industrial absorption refrigeration systems : systematic design and operation with technical, economic, and environmental objectives [texte imprimé] / José María Ponce-Ortega, Auteur ; Eman A. Tora, Auteur ; J. Betzabe Gonzalez-Campos, Auteur . - 2011 . - pp. 9667–9684.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9667–9684
Mots-clés : Design Refrigeration Résumé : This paper presents a new methodology for the energy integration of systems that require refrigeration. It considers the integration between process streams as well as that between the heat from process stream excess, solar energy, fossil fuels, and biofuels to run the stripper required by the absorption refrigeration (AR) needed. The proposed methodology consists of two stages: the first one identifies the energy targets, while the second one uses a new mathematical programming model to solve a multiobjective optimization mixed-integer linear programming (MILP) problem, allowing one to determine the minimum cost as well as the minimum greenhouse gas emissions (GHGE) to satisfy the utility requirements identified in the first stage. The proposed model considers the optimal selection of different types of solar collectors, and since the solar radiation depends on the season of the year, the model also accounts for the best combination of fossil and biofuels to complement the energy required for the AR. The proposed methodology is very useful to identify the scenario required to implement the use of clean energies in the refrigeration process. Three problems are presented to show the applicability of the proposed methodology, which does not exhibit numerical complications; these results show that process integration helps to get a given reduction in the GHGE economically attractive involving the use of dean energies, besides identifying the required tax credit to get economic and environmentally efficient cooling systems. In addition, because of the availability of the solar radiation, the solar collectors must be integrated with different types of energy, depending on the season of the year. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425211 Exemplaires
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Titre : Experimental validation of the calcium looping CO2 capture process with two circulating fluidized bed carbonator reactors Type de document : texte imprimé Auteurs : Alexander Charitos, Auteur ; Nuria Rodriguez, Auteur ; Craig Hawthorne, Auteur Année de publication : 2011 Article en page(s) : pp. 9685-9695 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Reactor Circulating fluidized bed Fluidization Carbon dioxide Résumé : Postcombustion CO2 capture using CaO as a regenerable solid sorbent in a circulating fluidized bed (CFB) carbonator is emerging as a promising CO2 capture technology. Experimental validation of this concept is provided through a comparative analysis of the results obtained in two laboratory-scale dual fluidized bed (DFB) installations located at INCAR-CSIC (Spain) and IFK (Germany). The analysis is focused on the performance of the CFB carbonator reactors operated with continuous solid circulation of CaO. A reasonable closure of the carbon balances (i) between the CO2 that has disappeared from the gas phase, (ii) the CaCO3 circulating between the reactors, and (iii) the CaCO3 that is formed within the carbonator bed has been established. A necessary condition for the capture of a given molar flow of CO2 is experimentally demonstrated and requires that a slightly overstoichiometric molar flow of active CaO is supplied to the carbonator. The deactivation behavior of the sorbents during continuous looping conditions has been measured. The key parameter to interpret the carbonator reactor results has been the active space time, that is indicative of the CaO inventory per molar flow of CO2 participating in the carbonation reaction and of the reaction rate of the solid inventory in the reactor. Two different approaches have been utilized in order to find a suitable expression for this parameter, thus achieving its correlation with the CO2 capture efficiency. A simple model assuming instant mixing of solids and plug-flow of the gas has been tested. Based mainly on carbonator active space time variation, the CO2 capture efficiency are shown to lie between 30% and above 90%. These results confirm the technical viability of the calcium looping postcombustion CO2 capture process. They have been used for designing the current pilot-plant facilities which are scaled up 20―50 times in regard to the lab-scale units. Moreover, the lab-scale results obtained allow for simulation work to be initiated in regard to the full scale Ca looping application. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425212
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9685-9695[article] Experimental validation of the calcium looping CO2 capture process with two circulating fluidized bed carbonator reactors [texte imprimé] / Alexander Charitos, Auteur ; Nuria Rodriguez, Auteur ; Craig Hawthorne, Auteur . - 2011 . - pp. 9685-9695.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9685-9695
Mots-clés : Reactor Circulating fluidized bed Fluidization Carbon dioxide Résumé : Postcombustion CO2 capture using CaO as a regenerable solid sorbent in a circulating fluidized bed (CFB) carbonator is emerging as a promising CO2 capture technology. Experimental validation of this concept is provided through a comparative analysis of the results obtained in two laboratory-scale dual fluidized bed (DFB) installations located at INCAR-CSIC (Spain) and IFK (Germany). The analysis is focused on the performance of the CFB carbonator reactors operated with continuous solid circulation of CaO. A reasonable closure of the carbon balances (i) between the CO2 that has disappeared from the gas phase, (ii) the CaCO3 circulating between the reactors, and (iii) the CaCO3 that is formed within the carbonator bed has been established. A necessary condition for the capture of a given molar flow of CO2 is experimentally demonstrated and requires that a slightly overstoichiometric molar flow of active CaO is supplied to the carbonator. The deactivation behavior of the sorbents during continuous looping conditions has been measured. The key parameter to interpret the carbonator reactor results has been the active space time, that is indicative of the CaO inventory per molar flow of CO2 participating in the carbonation reaction and of the reaction rate of the solid inventory in the reactor. Two different approaches have been utilized in order to find a suitable expression for this parameter, thus achieving its correlation with the CO2 capture efficiency. A simple model assuming instant mixing of solids and plug-flow of the gas has been tested. Based mainly on carbonator active space time variation, the CO2 capture efficiency are shown to lie between 30% and above 90%. These results confirm the technical viability of the calcium looping postcombustion CO2 capture process. They have been used for designing the current pilot-plant facilities which are scaled up 20―50 times in regard to the lab-scale units. Moreover, the lab-scale results obtained allow for simulation work to be initiated in regard to the full scale Ca looping application. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425212 Exemplaires
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Titre : Carbon filter process for flue-gas carbon capture on carbonaceous sorbents : steam-aided vacuum swing adsorption option Type de document : texte imprimé Auteurs : Bryce Dutcher, Auteur ; Hertanto Adidharma, Auteur ; Maciej Radosz, Auteur Année de publication : 2011 Article en page(s) : pp. 9696-9703 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Vacuum swing adsorption Water vapor Gaseous effluent Résumé : A low-pressure carbon filter process can capture carbon dioxide from combustion flue gas. This filter is filled with a carbonaceous sorbent, such as activated carbon, which has a high chemical affinity to and hence high capacity to retain CO2 but not nitrogen. This in turn leads to a high CO2/N2 selectivity, especially at low pressures. While CO2 sorption is spontaneous and rapid, its recovery from the sorbent is a challenge that determines the process efficiency. Among the desorption methods considered in this work, direct steam can produce nearly pure CO2, but it results in condensed water in the bed that reduces the sorbent capacity and requires sorbent cooling, which is slow. Vacuum desorption in the absence of water also works, but it requires low pressures, much lower than 30 Torr, to achieve substantial CO2 yields. However, a hybrid approach, referred to as "steam-aided vacuum swing adsorption" (SA-VSA), proposed in this work, is found to alleviate or eliminate these problems. Water vapor serves as a displacement medium and hence increases the vacuum efficiency at moderate pressures. Vacuum, on the other hand, prevents bulk water condensation and sorbent heating, and hence eliminates the need for cooling. As a result, SA-VSA can completely recover nearly pure CO2 from combustion flue gas, but it also allows for optimizing the CO2 recovery and purity. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425213
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9696-9703[article] Carbon filter process for flue-gas carbon capture on carbonaceous sorbents : steam-aided vacuum swing adsorption option [texte imprimé] / Bryce Dutcher, Auteur ; Hertanto Adidharma, Auteur ; Maciej Radosz, Auteur . - 2011 . - pp. 9696-9703.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9696-9703
Mots-clés : Vacuum swing adsorption Water vapor Gaseous effluent Résumé : A low-pressure carbon filter process can capture carbon dioxide from combustion flue gas. This filter is filled with a carbonaceous sorbent, such as activated carbon, which has a high chemical affinity to and hence high capacity to retain CO2 but not nitrogen. This in turn leads to a high CO2/N2 selectivity, especially at low pressures. While CO2 sorption is spontaneous and rapid, its recovery from the sorbent is a challenge that determines the process efficiency. Among the desorption methods considered in this work, direct steam can produce nearly pure CO2, but it results in condensed water in the bed that reduces the sorbent capacity and requires sorbent cooling, which is slow. Vacuum desorption in the absence of water also works, but it requires low pressures, much lower than 30 Torr, to achieve substantial CO2 yields. However, a hybrid approach, referred to as "steam-aided vacuum swing adsorption" (SA-VSA), proposed in this work, is found to alleviate or eliminate these problems. Water vapor serves as a displacement medium and hence increases the vacuum efficiency at moderate pressures. Vacuum, on the other hand, prevents bulk water condensation and sorbent heating, and hence eliminates the need for cooling. As a result, SA-VSA can completely recover nearly pure CO2 from combustion flue gas, but it also allows for optimizing the CO2 recovery and purity. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425213 Exemplaires
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Titre : A Population balance model on sorbent in CFB combustors : the influence of particle attrition Type de document : texte imprimé Auteurs : Fabio Montagnaro, Auteur ; Piero Salatino, Auteur ; Fabrizio Scala, Auteur Année de publication : 2011 Article en page(s) : pp. 9704-9711 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Attrition Modeling Population balance Résumé : A population balance model on sorbent particles in an atmospheric circulating fluidized bed combustor fueled with sulfur-bearing solid fuel is developed. The model aims at the prediction of the following quantities establishing at the steady state in the combustor: sorbent inventory and particle size distribution, partitioning of the sorbent between fly and bottom ash, desulfurization efficiency, and the mass flow rate of the sorbent circulating around the loop of the combustor. The core of the model is represented by the population balance equations on sorbent particles, which embody terms expressing the rate of sorbent attrition/fragmentation. The effect of the progress of sulfation on attrition is taken into account by the selection of appropriate constitutive equations. Model results are presented and discussed with the aim of clarifying the influence of particle attrition. In particular, the effect of attrition on bed sorbent partitioning between lime and sulfated lime and on SO2 capture efficiency is highlighted. The model enables one to assess the balance between opposed effects of attrition on desulfurization: on one hand, attrited fines are characterized by a better reactivity with respect to SO2, when compared with the mother particles; on the other hand, attrition is responsible for larger amounts of unsulfated material reporting to the fly ash. A sensitivity analysis is also carried out with reference to relevant operational parameters of the combustor in order to correlate changes in ash partitioning and desulfurization efficiency with the extent of sorbent attrition and solids circulation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425214
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9704-9711[article] A Population balance model on sorbent in CFB combustors : the influence of particle attrition [texte imprimé] / Fabio Montagnaro, Auteur ; Piero Salatino, Auteur ; Fabrizio Scala, Auteur . - 2011 . - pp. 9704-9711.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9704-9711
Mots-clés : Attrition Modeling Population balance Résumé : A population balance model on sorbent particles in an atmospheric circulating fluidized bed combustor fueled with sulfur-bearing solid fuel is developed. The model aims at the prediction of the following quantities establishing at the steady state in the combustor: sorbent inventory and particle size distribution, partitioning of the sorbent between fly and bottom ash, desulfurization efficiency, and the mass flow rate of the sorbent circulating around the loop of the combustor. The core of the model is represented by the population balance equations on sorbent particles, which embody terms expressing the rate of sorbent attrition/fragmentation. The effect of the progress of sulfation on attrition is taken into account by the selection of appropriate constitutive equations. Model results are presented and discussed with the aim of clarifying the influence of particle attrition. In particular, the effect of attrition on bed sorbent partitioning between lime and sulfated lime and on SO2 capture efficiency is highlighted. The model enables one to assess the balance between opposed effects of attrition on desulfurization: on one hand, attrited fines are characterized by a better reactivity with respect to SO2, when compared with the mother particles; on the other hand, attrition is responsible for larger amounts of unsulfated material reporting to the fly ash. A sensitivity analysis is also carried out with reference to relevant operational parameters of the combustor in order to correlate changes in ash partitioning and desulfurization efficiency with the extent of sorbent attrition and solids circulation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425214 Exemplaires
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Titre : Effective adsorption of anionic dye, alizarin red S, from aqueous solutions on activated clay modified by iron oxide Type de document : texte imprimé Auteurs : Feng Fu, Auteur ; Ziwei Gao, Auteur ; Lingxiang Gao, Auteur Année de publication : 2011 Article en page(s) : pp. 9712–9717 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Aqueous solution Dyes Adsorption Résumé : The present study aims to investigate the adsorption of anionic dye, alizarin red s (ARS), on activated clay modified by iron oxide (Fe-clay) in a batch reactor. The adsorption process reached equilibrium within 90 min, and the removal efficiency increased with the enhancement of initial dye concentration, adsorbent dosage, and contact time, but decreased with the enhancement of solution pH. The adsorption kinetics was investigated according to three theoretical models, but the best fit was achieved by the pseudosecond-order kinetics model. The adsorption isotherms could be well-defined with the Langmuir isotherm model instead of the Freundlich isotherm model, and the calculated maximum adsorption capacity was found to be 32.7 mg g–1. The obtained results indicate that Fe-clay is suitable for adsorption of ARS from aqueous solutions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425215
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9712–9717[article] Effective adsorption of anionic dye, alizarin red S, from aqueous solutions on activated clay modified by iron oxide [texte imprimé] / Feng Fu, Auteur ; Ziwei Gao, Auteur ; Lingxiang Gao, Auteur . - 2011 . - pp. 9712–9717.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9712–9717
Mots-clés : Aqueous solution Dyes Adsorption Résumé : The present study aims to investigate the adsorption of anionic dye, alizarin red s (ARS), on activated clay modified by iron oxide (Fe-clay) in a batch reactor. The adsorption process reached equilibrium within 90 min, and the removal efficiency increased with the enhancement of initial dye concentration, adsorbent dosage, and contact time, but decreased with the enhancement of solution pH. The adsorption kinetics was investigated according to three theoretical models, but the best fit was achieved by the pseudosecond-order kinetics model. The adsorption isotherms could be well-defined with the Langmuir isotherm model instead of the Freundlich isotherm model, and the calculated maximum adsorption capacity was found to be 32.7 mg g–1. The obtained results indicate that Fe-clay is suitable for adsorption of ARS from aqueous solutions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425215 Exemplaires
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Titre : Influences of seeds on the properties of zeolite NaA membranes on alumina hollow fibers Type de document : texte imprimé Auteurs : Jia Shao, Auteur ; Qinqin Ge, Auteur ; Lijun Shan, Auteur Année de publication : 2011 Article en page(s) : pp. 9718-9726 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hollow fiber Zeolite Résumé : The influences of size (90―1500 nm) and amount (1―4 wt %) of as-synthesized seed crystals on the properties of zeolite NaA membranes on alumina hollow fibers are investigated. Seeds and membranes are characterized by dynamic light scattering, X-ray diffraction, and scanning electron microscope. It is found that in order to prepare dense NaA membranes with high separation performance, for seeds smaller than 100 and 200 nm, the optimal concentrations are 1 and 3 wt %, respectively; while for large-sized seeds (>1500 nm), membranes obtained using the seed suspension with 4 wt % seed concentration still have defects. Furthermore, the influence of crystal fragments (∼50 nm) obtained by ball-milling available crystals (e.g., 1500 nm) on the formation of zeolite membrane is also studied. Based on the morphology and performance of membranes grown from different seeds, seed-assisted membrane formation process is briefly discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425216
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9718-9726[article] Influences of seeds on the properties of zeolite NaA membranes on alumina hollow fibers [texte imprimé] / Jia Shao, Auteur ; Qinqin Ge, Auteur ; Lijun Shan, Auteur . - 2011 . - pp. 9718-9726.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9718-9726
Mots-clés : Hollow fiber Zeolite Résumé : The influences of size (90―1500 nm) and amount (1―4 wt %) of as-synthesized seed crystals on the properties of zeolite NaA membranes on alumina hollow fibers are investigated. Seeds and membranes are characterized by dynamic light scattering, X-ray diffraction, and scanning electron microscope. It is found that in order to prepare dense NaA membranes with high separation performance, for seeds smaller than 100 and 200 nm, the optimal concentrations are 1 and 3 wt %, respectively; while for large-sized seeds (>1500 nm), membranes obtained using the seed suspension with 4 wt % seed concentration still have defects. Furthermore, the influence of crystal fragments (∼50 nm) obtained by ball-milling available crystals (e.g., 1500 nm) on the formation of zeolite membrane is also studied. Based on the morphology and performance of membranes grown from different seeds, seed-assisted membrane formation process is briefly discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425216 Exemplaires
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Titre : Effect of agglomerate size on oil removal during microwave treatment of oil contaminated drill cuttings Type de document : texte imprimé Auteurs : Igor S. M. Pereira, Auteur ; John P. Robinson, Auteur ; Sam W. kingman, Auteur Année de publication : 2011 Article en page(s) : pp. 9727-9734 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Cutting Pollution Microwave Résumé : This paper presents new observations on the effects of agglomerate size on microwave treatment of drill cuttings. A continuous pilot scale microwave heating system was used at power levels from 17 to 42 kW and material throughputs from 190 to 300 kg/h. It was found that oil is preferentially removed from smaller agglomerates and that feed materials larger than 1 mm required up to 15% more energy to be remediated to the same levels of residual oil as DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425217
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9727-9734[article] Effect of agglomerate size on oil removal during microwave treatment of oil contaminated drill cuttings [texte imprimé] / Igor S. M. Pereira, Auteur ; John P. Robinson, Auteur ; Sam W. kingman, Auteur . - 2011 . - pp. 9727-9734.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9727-9734
Mots-clés : Cutting Pollution Microwave Résumé : This paper presents new observations on the effects of agglomerate size on microwave treatment of drill cuttings. A continuous pilot scale microwave heating system was used at power levels from 17 to 42 kW and material throughputs from 190 to 300 kg/h. It was found that oil is preferentially removed from smaller agglomerates and that feed materials larger than 1 mm required up to 15% more energy to be remediated to the same levels of residual oil as DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425217 Exemplaires
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Titre : Modeling the turbulent flow of pulp suspensions Type de document : texte imprimé Auteurs : Carla A.F. Ventura, Auteur ; Fernando A.P. Garcia, Auteur ; Paulo J. Ferreira, Auteur Année de publication : 2011 Article en page(s) : pp. 9735-9742 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Turbulent flow Modeling Résumé : Pulp fiber suspensions are complex systems because the components present singular and complex interactions between them. A mechanistic model for the turbulent flow regime of industrial pulp suspensions was developed on the basis of a CFD code, using the chemical engineering module of COMSOL Multiphysics software. The standard k-ε turbulence model, chosen to simulate turbulence, was tested and validated using four different industrial pulp suspensions previously characterized experimentally. The modeled pressure drop profiles agree very well with the experimental results obtained in a pilot rig. Therefore, the k-ε turbulence model for the simulation of pulp fiber suspension flows, associated with experimental rheological data, proved to be a prompt strategy to attain good prediction of pressure drop for fiber suspension flows. Moreover, the adjustment of the turbulence parameters confirmed previous studies, where it was concluded that the existence of particles, such as fibers, in a fluid flow induces a turbulence damping. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425218
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9735-9742[article] Modeling the turbulent flow of pulp suspensions [texte imprimé] / Carla A.F. Ventura, Auteur ; Fernando A.P. Garcia, Auteur ; Paulo J. Ferreira, Auteur . - 2011 . - pp. 9735-9742.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9735-9742
Mots-clés : Turbulent flow Modeling Résumé : Pulp fiber suspensions are complex systems because the components present singular and complex interactions between them. A mechanistic model for the turbulent flow regime of industrial pulp suspensions was developed on the basis of a CFD code, using the chemical engineering module of COMSOL Multiphysics software. The standard k-ε turbulence model, chosen to simulate turbulence, was tested and validated using four different industrial pulp suspensions previously characterized experimentally. The modeled pressure drop profiles agree very well with the experimental results obtained in a pilot rig. Therefore, the k-ε turbulence model for the simulation of pulp fiber suspension flows, associated with experimental rheological data, proved to be a prompt strategy to attain good prediction of pressure drop for fiber suspension flows. Moreover, the adjustment of the turbulence parameters confirmed previous studies, where it was concluded that the existence of particles, such as fibers, in a fluid flow induces a turbulence damping. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425218 Exemplaires
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Titre : High-octane gasoline production by upgrading low-temperature fischer–tropsch syncrude Type de document : texte imprimé Auteurs : Xiangbo Guo, Auteur ; Guangjian Liu, Auteur ; Eric D. Larson, Auteur Année de publication : 2011 Article en page(s) : pp. 9743-9747 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Low temperature Upgrading Production Résumé : Technology selection for refining the lighter fractions of syncrude produced by low-temperatore Fischer―Tropsch (LTFT) synthesis into high octane motor-gasoline with no decrease in distillate production has been investigated. It was found that an upgrading scheme based on Pt/Lzeolite reforming, non-hydrogen aromatization and olefin oligomerization can produce high quality motor gasoline which can meet current gasoline specifications (Euro-4). A second scheme, which we call "full aromatization", is also evaluated on the basis of liquid yield and octane number. The full aromatization process appears to be the least complex refining scheme that provides a sufficiently high octane number, but the gasoline produced from this process may require additives to meet current motor gasoline specifications. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425219
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9743-9747[article] High-octane gasoline production by upgrading low-temperature fischer–tropsch syncrude [texte imprimé] / Xiangbo Guo, Auteur ; Guangjian Liu, Auteur ; Eric D. Larson, Auteur . - 2011 . - pp. 9743-9747.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9743-9747
Mots-clés : Low temperature Upgrading Production Résumé : Technology selection for refining the lighter fractions of syncrude produced by low-temperatore Fischer―Tropsch (LTFT) synthesis into high octane motor-gasoline with no decrease in distillate production has been investigated. It was found that an upgrading scheme based on Pt/Lzeolite reforming, non-hydrogen aromatization and olefin oligomerization can produce high quality motor gasoline which can meet current gasoline specifications (Euro-4). A second scheme, which we call "full aromatization", is also evaluated on the basis of liquid yield and octane number. The full aromatization process appears to be the least complex refining scheme that provides a sufficiently high octane number, but the gasoline produced from this process may require additives to meet current motor gasoline specifications. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425219 Exemplaires
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Titre : Measurement of thermophysical pure component properties for a few siloxanes used as working fluids for organic rankine cycles Type de document : texte imprimé Auteurs : Rima Abbas, Auteur ; Andre Schedemann, Auteur ; Christian Ihmels, Auteur Année de publication : 2011 Article en page(s) : pp. 9748-9757 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Thermophysical Siloxanes Résumé : In this work, heat capacities for three linear siloxanes (hexamethyl disiloxane (MM), octamethyltrisiloxane (MDM), and decamethyltetrasiloxane (MD2M)) in the temperature range of 205.15―395.15 K and for two cyclic siloxanes (octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (Ds)) in the temperature range of 288.15―443.15 K have been measured with the help of a Tian―Calvert calorimeter. Furthermore, vapor pressures for the five mentioned compounds in the temperature range of 250―620 K and pressures from 2 mbar to 1 bar have been determined with the help of a Scott ebulliometer. The prediction of the heat capacities using the group contribution equation of state VTPR were improved by fitting the Twu parameters simultaneously to the new vapor pressure and heat capacity data. In addition, melting temperatures and heat of fusions for these five siloxanes have been measured using a differential scanning calorimeter (DSC). Furthermore, density measurements for the three linear siloxanes (MM, MDM, and MD2M) between 278 and 437 K and pressures up to 130 MPa were carried out using a vibrating tube densimeter. The densities were correlated with the TRIDEN model. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425220
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9748-9757[article] Measurement of thermophysical pure component properties for a few siloxanes used as working fluids for organic rankine cycles [texte imprimé] / Rima Abbas, Auteur ; Andre Schedemann, Auteur ; Christian Ihmels, Auteur . - 2011 . - pp. 9748-9757.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9748-9757
Mots-clés : Thermophysical Siloxanes Résumé : In this work, heat capacities for three linear siloxanes (hexamethyl disiloxane (MM), octamethyltrisiloxane (MDM), and decamethyltetrasiloxane (MD2M)) in the temperature range of 205.15―395.15 K and for two cyclic siloxanes (octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (Ds)) in the temperature range of 288.15―443.15 K have been measured with the help of a Tian―Calvert calorimeter. Furthermore, vapor pressures for the five mentioned compounds in the temperature range of 250―620 K and pressures from 2 mbar to 1 bar have been determined with the help of a Scott ebulliometer. The prediction of the heat capacities using the group contribution equation of state VTPR were improved by fitting the Twu parameters simultaneously to the new vapor pressure and heat capacity data. In addition, melting temperatures and heat of fusions for these five siloxanes have been measured using a differential scanning calorimeter (DSC). Furthermore, density measurements for the three linear siloxanes (MM, MDM, and MD2M) between 278 and 437 K and pressures up to 130 MPa were carried out using a vibrating tube densimeter. The densities were correlated with the TRIDEN model. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425220 Exemplaires
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Titre : Estimating specific chemical exergy of biomass from basic analysis data Type de document : texte imprimé Auteurs : Guohui Song, Auteur ; Laihong Shen, Auteur ; Jun Xiao, Auteur Année de publication : 2011 Article en page(s) : pp. 9758-9766 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Biomass Résumé : Estimation of chemical exergy of biomass is one of the basic steps in performance analysis and optimization of biomass conversion systems. A practical method for estimating specific chemical exergy of biomass on dry basis (db) from basic analysis data was developed on Szargut's reference environment model. The method is based on exergy and entropy equations of reaction, Gibbs free energy relations, a modified estimation of the standard entropy of organic matter in biomass and an assumption about original state of inorganic matter-forming elements in biomass. The method was applied to 86 varieties of biomass, and the statistical results indicate that specific chemical exergy of dry biomass varies in the interval of 11.5―24.2 MJ·kg―1, which is always slightly larger than the higher heat value (HHV) (db). Owing to the relative very small value, the influence of inorganic matter in the form of chemical exergies of ash and oxygen reacting with inorganic matter, and the entropy change in ash formation can be neglected. The average ratio of specific chemical exergy to HHV is 1.047 for dry biomass. Consequently, specific chemical exergy of dry biomass can be conveniently estimated from ultimate analysis data plus ash content (in wt %, db) or HHV. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425221
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9758-9766[article] Estimating specific chemical exergy of biomass from basic analysis data [texte imprimé] / Guohui Song, Auteur ; Laihong Shen, Auteur ; Jun Xiao, Auteur . - 2011 . - pp. 9758-9766.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9758-9766
Mots-clés : Biomass Résumé : Estimation of chemical exergy of biomass is one of the basic steps in performance analysis and optimization of biomass conversion systems. A practical method for estimating specific chemical exergy of biomass on dry basis (db) from basic analysis data was developed on Szargut's reference environment model. The method is based on exergy and entropy equations of reaction, Gibbs free energy relations, a modified estimation of the standard entropy of organic matter in biomass and an assumption about original state of inorganic matter-forming elements in biomass. The method was applied to 86 varieties of biomass, and the statistical results indicate that specific chemical exergy of dry biomass varies in the interval of 11.5―24.2 MJ·kg―1, which is always slightly larger than the higher heat value (HHV) (db). Owing to the relative very small value, the influence of inorganic matter in the form of chemical exergies of ash and oxygen reacting with inorganic matter, and the entropy change in ash formation can be neglected. The average ratio of specific chemical exergy to HHV is 1.047 for dry biomass. Consequently, specific chemical exergy of dry biomass can be conveniently estimated from ultimate analysis data plus ash content (in wt %, db) or HHV. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425221 Exemplaires
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Titre : Experimental study of drop size distribution in the bag breakup regime Type de document : texte imprimé Auteurs : Hui Zhao, Auteur ; Hai Feng Liu, Auteur ; Jian Liang Xu, Auteur Année de publication : 2011 Article en page(s) : pp. 9767-9773 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Particle size distribution Drop Résumé : The situation of a liquid drop exposed to a continuous air jet flow was investigated experimentally. The drop bag breakup of test liquids which included water, ethanol, and various glycerol mixtures was observed using a high-speed camera. The morphological change, such as drop deformation, was observed and analyzed. Mean fragment sizes were obtained, which were in good agreement with those reported in the literature. Big fragments formed from the ring contained the great mass of the initial drop and were studied in detail, and correlations on fragment mean size and number were obtained. Mean size decreased with the Weber number and increased with the Ohnesorge number; fragment number was in contrast to mean size. Fragment size distribution was another useful parameter. Our results showed that fragment size distribution based on the number formed from the ring was a gamma distribution. Fragment size distribution based on the number formed from the whole drop was an exponential distribution. We also investigated fragment size distribution based on the volume formed from the whole drop, which was a Rosin―Rammler distribution. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425222
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9767-9773[article] Experimental study of drop size distribution in the bag breakup regime [texte imprimé] / Hui Zhao, Auteur ; Hai Feng Liu, Auteur ; Jian Liang Xu, Auteur . - 2011 . - pp. 9767-9773.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9767-9773
Mots-clés : Particle size distribution Drop Résumé : The situation of a liquid drop exposed to a continuous air jet flow was investigated experimentally. The drop bag breakup of test liquids which included water, ethanol, and various glycerol mixtures was observed using a high-speed camera. The morphological change, such as drop deformation, was observed and analyzed. Mean fragment sizes were obtained, which were in good agreement with those reported in the literature. Big fragments formed from the ring contained the great mass of the initial drop and were studied in detail, and correlations on fragment mean size and number were obtained. Mean size decreased with the Weber number and increased with the Ohnesorge number; fragment number was in contrast to mean size. Fragment size distribution was another useful parameter. Our results showed that fragment size distribution based on the number formed from the ring was a gamma distribution. Fragment size distribution based on the number formed from the whole drop was an exponential distribution. We also investigated fragment size distribution based on the volume formed from the whole drop, which was a Rosin―Rammler distribution. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425222 Exemplaires
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Titre : Experimental and theoretical study of chemical equilibria in the reacting system of the di-alkyl carbonate synthesis Type de document : texte imprimé Auteurs : Sergey P. Verevkin, Auteur ; Vladimir N. Emel'yanenko, Auteur ; Svetlana A. Kozlova, Auteur Année de publication : 2011 Article en page(s) : pp. 9774-9780 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Chemical equilibrium Résumé : The chemical equilibrium of the reactive system (propylene carbonate + butanol = dibutyl carbonate +1,2-propanediol) was studied in the temperature range (303 to 373) K in the liquid phase using the method of sealed ampules using K2CO3 as heterogeneous catalyst. This reactive system exhibits a strong nonideal behavior of the mixture compounds in the liquid phase. The knowledge of the activity coefficients is required in order to obtain the thermodynamic equilibrium constants Ka. A well established procedure, COSMO-RS, has been used to assess activity coefficients of the reaction participants in the liquid phase. Enthalpies of reactions of the dialkyl carbonate synthesis reaction in the liquid phase were obtained from temperature dependences of the corresponding thermodynamic equilibrium constants. For the sake of comparison, high-level ab initio calculations of the reaction participants have been performed using the GAUSSIAN-03 program package. Absolute electronic energy values of the molecules have been obtained using G3MP2 level. Using these results calculated equilibrium constants and enthalpies of reaction of the dialkyl carbonates synthesis in the liquid phase based on the principles of statistical thermodynamics are found to be in acceptable agreement with the data obtained from the thermochemical measurements. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425223
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9774-9780[article] Experimental and theoretical study of chemical equilibria in the reacting system of the di-alkyl carbonate synthesis [texte imprimé] / Sergey P. Verevkin, Auteur ; Vladimir N. Emel'yanenko, Auteur ; Svetlana A. Kozlova, Auteur . - 2011 . - pp. 9774-9780.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9774-9780
Mots-clés : Chemical equilibrium Résumé : The chemical equilibrium of the reactive system (propylene carbonate + butanol = dibutyl carbonate +1,2-propanediol) was studied in the temperature range (303 to 373) K in the liquid phase using the method of sealed ampules using K2CO3 as heterogeneous catalyst. This reactive system exhibits a strong nonideal behavior of the mixture compounds in the liquid phase. The knowledge of the activity coefficients is required in order to obtain the thermodynamic equilibrium constants Ka. A well established procedure, COSMO-RS, has been used to assess activity coefficients of the reaction participants in the liquid phase. Enthalpies of reactions of the dialkyl carbonate synthesis reaction in the liquid phase were obtained from temperature dependences of the corresponding thermodynamic equilibrium constants. For the sake of comparison, high-level ab initio calculations of the reaction participants have been performed using the GAUSSIAN-03 program package. Absolute electronic energy values of the molecules have been obtained using G3MP2 level. Using these results calculated equilibrium constants and enthalpies of reaction of the dialkyl carbonates synthesis in the liquid phase based on the principles of statistical thermodynamics are found to be in acceptable agreement with the data obtained from the thermochemical measurements. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425223 Exemplaires
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Titre : Effects of starch on latex migration and on paper coating properties Type de document : texte imprimé Auteurs : Yanfen Du, Auteur ; Yong-Hua Zang, Auteur ; Juan Du, Auteur Année de publication : 2011 Article en page(s) : pp. 9781-9786 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Migration Résumé : With increasing awareness of environmental protection and the surging cost of petroleum chemicals, eco-friendly polymer starches are being increasingly used as cobinders to partly replace synthetic polymer latex in the production of high quality coated papers. In this work, the influences of starch on latex migration and on properties of model day coatings were investigated, in order to better understand interactions between starch and latex and their effects on coating structure development. The results showed that surface carbon content determined from XPS measurements decreased significantly with increasing starch content. This unexpected finding of lower surface carbon content for coatings ofhigher binder content was explained by assuming that watersoluble starch migrated to the surface would move back into the coating pores as an integral part of the aqueous phase, as the air-water interfaces recede from the coating surface into the capillaries during drying. It has also been found that gloss and porosity of the coatings decreased with starch addition, as expected. However, the K and N ink absorbency values increased with increasing binder content, contradicting literature results for coatings of sole binder systems. This finding was attributed to reduced binder migration to the surface, resulting in a more open surface structure, since surface carbon content decreased with increasing starch addition. DEWEY : 660 ISSN : 0888-5885 En ligne : http://www.refdoc.fr/Noticeresultat
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9781-9786[article] Effects of starch on latex migration and on paper coating properties [texte imprimé] / Yanfen Du, Auteur ; Yong-Hua Zang, Auteur ; Juan Du, Auteur . - 2011 . - pp. 9781-9786.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9781-9786
Mots-clés : Migration Résumé : With increasing awareness of environmental protection and the surging cost of petroleum chemicals, eco-friendly polymer starches are being increasingly used as cobinders to partly replace synthetic polymer latex in the production of high quality coated papers. In this work, the influences of starch on latex migration and on properties of model day coatings were investigated, in order to better understand interactions between starch and latex and their effects on coating structure development. The results showed that surface carbon content determined from XPS measurements decreased significantly with increasing starch content. This unexpected finding of lower surface carbon content for coatings ofhigher binder content was explained by assuming that watersoluble starch migrated to the surface would move back into the coating pores as an integral part of the aqueous phase, as the air-water interfaces recede from the coating surface into the capillaries during drying. It has also been found that gloss and porosity of the coatings decreased with starch addition, as expected. However, the K and N ink absorbency values increased with increasing binder content, contradicting literature results for coatings of sole binder systems. This finding was attributed to reduced binder migration to the surface, resulting in a more open surface structure, since surface carbon content decreased with increasing starch addition. DEWEY : 660 ISSN : 0888-5885 En ligne : http://www.refdoc.fr/Noticeresultat Exemplaires
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Titre : Dynamic simulation of the packing of ellipsoidal particles Type de document : texte imprimé Auteurs : Zong-Yan Zhou, Auteur ; Rui-Ping Zou, Auteur ; David Pinson, Auteur Année de publication : 2011 Article en page(s) : pp. 9787-9798 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Modeling Dynamic model Résumé : This paper presents a numerical study of the packing of nonspherical particles by the use of the discrete element method. The shapes considered are oblate and prolate spheroids, with the aspect ratio varying from 0.1 to 7.0. It is shown that the predicted relationship between packing fraction and aspect ratio is consistent with those reported in the literature. Ellipsoids can pack more densely than spheres. The maximum packing fraction occurs at an aspect ratio of 0.6 for oblate spheroids, and 1.80 for prolate spheroids. The packing characteristics with aspect ratio are further analyzed in terms of structural parameters such as coordination number and radial distribution function. It is shown that ellipsoids with small or large aspect ratios tend to give a locally ordered structure. The results demonstrate that DEM provides a useful method to investigate the packing dynamics of ellipsoidal particles. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425225
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9787-9798[article] Dynamic simulation of the packing of ellipsoidal particles [texte imprimé] / Zong-Yan Zhou, Auteur ; Rui-Ping Zou, Auteur ; David Pinson, Auteur . - 2011 . - pp. 9787-9798.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9787-9798
Mots-clés : Modeling Dynamic model Résumé : This paper presents a numerical study of the packing of nonspherical particles by the use of the discrete element method. The shapes considered are oblate and prolate spheroids, with the aspect ratio varying from 0.1 to 7.0. It is shown that the predicted relationship between packing fraction and aspect ratio is consistent with those reported in the literature. Ellipsoids can pack more densely than spheres. The maximum packing fraction occurs at an aspect ratio of 0.6 for oblate spheroids, and 1.80 for prolate spheroids. The packing characteristics with aspect ratio are further analyzed in terms of structural parameters such as coordination number and radial distribution function. It is shown that ellipsoids with small or large aspect ratios tend to give a locally ordered structure. The results demonstrate that DEM provides a useful method to investigate the packing dynamics of ellipsoidal particles. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425225 Exemplaires
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Titre : Monitoring the ozonation of phenol solutions at constant pH by different methods Type de document : texte imprimé Auteurs : Edgardo M. Contreras, Auteur ; Nora C. Bertola, Auteur ; Noemi E. Zaritzky, Auteur Année de publication : 2011 Article en page(s) : pp. 9799-9809 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : pH Ozonization Surveillance Résumé : In this study the oxidation―reduction potential (ORP) and the proton production (Hp) profiles as a function of time were proposed as indicators to monitor the ozonation of phenol solutions at constant pH. Analysis of the ozone gas outlet stream (XO3), COD, and phenol measurements in the aqueous phase confirm the reliability of the proposed indicators. Results show that the derivative with respect to time of the normalized ozone gas outlet concentration ((1/XO30)dXO3/dt), of the oxidation―reduction potential (dORP/dt) or of its logarithmic value (dLog(ORP)/dt), and of the proton production rate (dHp/dt) exhibited maximum values that were close to the critical ozonation time (tc) determined by XO3, COD, and phenol measurements. Additionally, ORP and XO3 measurements were useful to determine tc for all the tested pHs (5 to 11); however, Hp was useful only for pH values higher than 9. The indicators of the ozonation process proposed in the present work (ORP, Hp) as alternatives of XO3 may be useful to control the addition of ozone, minimizing the ozonation process costs. Note de contenu : http://atcatalogue_2.enp.edu.dz/catalog.php?categ=serials&sub=analysis&action=analysis_form&bul_id=15578&analysis_id=0 DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425226
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9799-9809[article] Monitoring the ozonation of phenol solutions at constant pH by different methods [texte imprimé] / Edgardo M. Contreras, Auteur ; Nora C. Bertola, Auteur ; Noemi E. Zaritzky, Auteur . - 2011 . - pp. 9799-9809.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9799-9809
Mots-clés : pH Ozonization Surveillance Résumé : In this study the oxidation―reduction potential (ORP) and the proton production (Hp) profiles as a function of time were proposed as indicators to monitor the ozonation of phenol solutions at constant pH. Analysis of the ozone gas outlet stream (XO3), COD, and phenol measurements in the aqueous phase confirm the reliability of the proposed indicators. Results show that the derivative with respect to time of the normalized ozone gas outlet concentration ((1/XO30)dXO3/dt), of the oxidation―reduction potential (dORP/dt) or of its logarithmic value (dLog(ORP)/dt), and of the proton production rate (dHp/dt) exhibited maximum values that were close to the critical ozonation time (tc) determined by XO3, COD, and phenol measurements. Additionally, ORP and XO3 measurements were useful to determine tc for all the tested pHs (5 to 11); however, Hp was useful only for pH values higher than 9. The indicators of the ozonation process proposed in the present work (ORP, Hp) as alternatives of XO3 may be useful to control the addition of ozone, minimizing the ozonation process costs. Note de contenu : http://atcatalogue_2.enp.edu.dz/catalog.php?categ=serials&sub=analysis&action=analysis_form&bul_id=15578&analysis_id=0 DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425226 Exemplaires
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Titre : Thermodynamics of mixtures containing amines. X. systems with cyclic amines or morpholine Type de document : texte imprimé Auteurs : Juan Antonio Gonzalez, Auteur Année de publication : 2011 Article en page(s) : pp. 9810-9820 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : thermodynamic Amines Morpholine Résumé : Cyclic amine or morpholine + organic solvent mixtures have been investigated in terms of DISQUAC and of the Kirkwood―Buffformalism. The amines considered are cyclohexylamine; (c-CH2)uNH (u = 2―7) and (c-CH2)uN―CH3 (u = 4,5). The organic solvents are alkanes and methanol or ethanol. The DISQUAC interaction parameters are reported. The model describes correctly a whole set of thermodynamic properties: vapor―liquid equilibria (VLE); excess Gibbs energies, GEm; excess enthalpies, HEm; excess heat capacities at constant pressure, CEP,m; and partial excess enthalpies at infinite dilution, HE,∞1, as well as the main features of the Kirkwood―Buff integrak. In (c-CH2)uNH + C6H12 mixtures, amine-amine interactions become weaker with increased u values. This is supported by the corresponding decrease of HEm and HE,∞1 and of the effective dipole moment. Interactions between amine molecules are also weakened when passing from a primary cyclic amine to an isomeric tertiary cyclic amine. The existence of an aromatic ring in the amine, as in aniline or pyridine, leads to stronger amine―amine interactions. Dipolar interactions between morpholine molecules are stronger than those between piperidine molecules, and reveal the existence of proximity effects between the two groups of morpholine. In systems with alkanes, interactions between amine molecules are preferred to those between unlike molecules. In piperidine + methanol and pyrrolidine + ethanol systems, the mixture structure is close to random mixing. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201120h
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9810-9820[article] Thermodynamics of mixtures containing amines. X. systems with cyclic amines or morpholine [texte imprimé] / Juan Antonio Gonzalez, Auteur . - 2011 . - pp. 9810-9820.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9810-9820
Mots-clés : thermodynamic Amines Morpholine Résumé : Cyclic amine or morpholine + organic solvent mixtures have been investigated in terms of DISQUAC and of the Kirkwood―Buffformalism. The amines considered are cyclohexylamine; (c-CH2)uNH (u = 2―7) and (c-CH2)uN―CH3 (u = 4,5). The organic solvents are alkanes and methanol or ethanol. The DISQUAC interaction parameters are reported. The model describes correctly a whole set of thermodynamic properties: vapor―liquid equilibria (VLE); excess Gibbs energies, GEm; excess enthalpies, HEm; excess heat capacities at constant pressure, CEP,m; and partial excess enthalpies at infinite dilution, HE,∞1, as well as the main features of the Kirkwood―Buff integrak. In (c-CH2)uNH + C6H12 mixtures, amine-amine interactions become weaker with increased u values. This is supported by the corresponding decrease of HEm and HE,∞1 and of the effective dipole moment. Interactions between amine molecules are also weakened when passing from a primary cyclic amine to an isomeric tertiary cyclic amine. The existence of an aromatic ring in the amine, as in aniline or pyridine, leads to stronger amine―amine interactions. Dipolar interactions between morpholine molecules are stronger than those between piperidine molecules, and reveal the existence of proximity effects between the two groups of morpholine. In systems with alkanes, interactions between amine molecules are preferred to those between unlike molecules. In piperidine + methanol and pyrrolidine + ethanol systems, the mixture structure is close to random mixing. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201120h Exemplaires
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Titre : Iterative feedback tuning of PID controllers for reactive distillation processes : a comparison with relay feedback tuning Type de document : texte imprimé Auteurs : Steffen Sommer, Auteur ; Peter Muller, Auteur ; Achim Kienle, Auteur Année de publication : 2011 Article en page(s) : pp. 9821-9828 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Distillation with reaction Differential integral proportional control Feedback Résumé : The iterative feedback tuning approach is used to design decentralized PID controllers for an ideal two-product reactive distillation column. The method is compared with relay feedback tuning including Tyreus-Luyben tuning rules. A control structure where two tray temperatures are the controlled variables and the feeds are the manipulated variables is considered. It is shown that iterative feedback tuning gives superior performance, compared to standard relay feedback. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425228
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9821-9828[article] Iterative feedback tuning of PID controllers for reactive distillation processes : a comparison with relay feedback tuning [texte imprimé] / Steffen Sommer, Auteur ; Peter Muller, Auteur ; Achim Kienle, Auteur . - 2011 . - pp. 9821-9828.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9821-9828
Mots-clés : Distillation with reaction Differential integral proportional control Feedback Résumé : The iterative feedback tuning approach is used to design decentralized PID controllers for an ideal two-product reactive distillation column. The method is compared with relay feedback tuning including Tyreus-Luyben tuning rules. A control structure where two tray temperatures are the controlled variables and the feeds are the manipulated variables is considered. It is shown that iterative feedback tuning gives superior performance, compared to standard relay feedback. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425228 Exemplaires
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