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Vol. 48 N° 7 - Avril 2009 [texte imprimé] . - 2009 . - p. 3261-3702 : ill. ; 28 cm. Chemical engineering Langues : Anglais (eng)
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Ajouter le résultat dans votre panierSynthesis of N-methylimidazolium functionalized strongly basic anion exchange resins for adsorption of Cr(VI) / Lili Zhu in Industrial & engineering chemistry research, Vol. 48 N° 7 (Avril 2009)
Titre : Synthesis of N-methylimidazolium functionalized strongly basic anion exchange resins for adsorption of Cr(VI) Type de document : texte imprimé Auteurs : Lili Zhu, Auteur ; Yinghui Liu, Auteur ; Ji, Chen, Auteur Année de publication : 2009 Article en page(s) : pp. 3261–3267 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : N-Methylimidazolium Cr(VI) Aqueous solution Adsorption Résumé : N-Methylimidazolium functionalized strongly basic anion exchange resins in the Cl− form (RCl) and SO42− form (R2SO4) were synthesized and employed for adsorption of Cr(VI) from aqueous solution. FT-IR and elementary analysis proved the structures of anion exchange resins and the content of functional groups. The gel-type strongly basic anion exchange resins had high thermal stability according to TGA and good chemical stability under the experimental conditions. The adsorption behaviors of Cr(VI) on RCl and R2SO4 were studied using the batch technique. It was shown that adsorption equilibrium was reached rapidly within 60 min. The adsorption data for RCl and R2SO4 were consistent with the Langmuir isotherm equation. The maximum adsorption capacities of RCl and R2SO4 were 132 and 125 mg/g, respectively, with almost all active sites fully occupied. RCl and R2SO4 could be used in the wide pH range 1−12 and were very suitable to remove Cr(VI) at a low concentration level. They also showed great preference to Cr(VI) compared to the other counterions. RCl was easily regenerated using the mixed solution of 0.3 mol/L NaOH and 0.3 mol/L NaCl, and retained nearly 100% of its orginal capacity during four cycles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801278f
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3261–3267[article] Synthesis of N-methylimidazolium functionalized strongly basic anion exchange resins for adsorption of Cr(VI) [texte imprimé] / Lili Zhu, Auteur ; Yinghui Liu, Auteur ; Ji, Chen, Auteur . - 2009 . - pp. 3261–3267.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3261–3267
Mots-clés : N-Methylimidazolium Cr(VI) Aqueous solution Adsorption Résumé : N-Methylimidazolium functionalized strongly basic anion exchange resins in the Cl− form (RCl) and SO42− form (R2SO4) were synthesized and employed for adsorption of Cr(VI) from aqueous solution. FT-IR and elementary analysis proved the structures of anion exchange resins and the content of functional groups. The gel-type strongly basic anion exchange resins had high thermal stability according to TGA and good chemical stability under the experimental conditions. The adsorption behaviors of Cr(VI) on RCl and R2SO4 were studied using the batch technique. It was shown that adsorption equilibrium was reached rapidly within 60 min. The adsorption data for RCl and R2SO4 were consistent with the Langmuir isotherm equation. The maximum adsorption capacities of RCl and R2SO4 were 132 and 125 mg/g, respectively, with almost all active sites fully occupied. RCl and R2SO4 could be used in the wide pH range 1−12 and were very suitable to remove Cr(VI) at a low concentration level. They also showed great preference to Cr(VI) compared to the other counterions. RCl was easily regenerated using the mixed solution of 0.3 mol/L NaOH and 0.3 mol/L NaCl, and retained nearly 100% of its orginal capacity during four cycles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801278f Exemplaires
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Titre : Epoxidation of methyl oleate using heterogeneous catalyst Type de document : texte imprimé Auteurs : Paulo A. Z. Suarez, Auteur ; Mírian S. C. Pereira, Auteur ; Kenneth M. Doll, Auteur Année de publication : 2009 Article en page(s) : pp. 3268–3270 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Alumina Catalytic activity Methyl oleate Hydrogen peroxide solution Résumé : In this work, we studied the catalytic activity of commercial alumina, and laboratory-synthesized alumina doped with Lewis acid metals, in the epoxidation of methyl oleate with aqueous hydrogen peroxide. It was observed that the reaction yields increased when the amount of catalyst, the quantity of hydrogen peroxide, the concentration of the hydrogen peroxide solution, or the surface area of the catalyst was increased. Reaction yields decreased when the surface acidity of the alumina was modified by doping with Lewis acid metals. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801635b
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3268–3270[article] Epoxidation of methyl oleate using heterogeneous catalyst [texte imprimé] / Paulo A. Z. Suarez, Auteur ; Mírian S. C. Pereira, Auteur ; Kenneth M. Doll, Auteur . - 2009 . - pp. 3268–3270.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3268–3270
Mots-clés : Alumina Catalytic activity Methyl oleate Hydrogen peroxide solution Résumé : In this work, we studied the catalytic activity of commercial alumina, and laboratory-synthesized alumina doped with Lewis acid metals, in the epoxidation of methyl oleate with aqueous hydrogen peroxide. It was observed that the reaction yields increased when the amount of catalyst, the quantity of hydrogen peroxide, the concentration of the hydrogen peroxide solution, or the surface area of the catalyst was increased. Reaction yields decreased when the surface acidity of the alumina was modified by doping with Lewis acid metals. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801635b Exemplaires
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Titre : Kinetics of glucose isomerization to fructose by immobilized glucose isomerase (sweetzyme IT) Type de document : texte imprimé Auteurs : Asghar Molaei Dehkordi, Auteur ; Mehrdad Shoai Tehrany, Auteur ; Iman Safari, Auteur Année de publication : 2009 Article en page(s) : pp. 3271–3278 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Immobilized glucose isomerase Stirred-tank reactor Fructose isomerization reaction Arrhenius-like expressions Résumé : We present the kinetic parameters and equilibrium constant of the enzymatic glucose−fructose isomerization reaction with an immobilized glucose isomerase (IGI), Sweetzyme IT, using a batch stirred-tank reactor following the procedure developed by Dehkordi et al. ( AIChE J. 2008, 54, 1333). The model predictions were compared with the experimental data and fair agreements were found. The influence of temperature on the equilibrium constant and kinetic parameters of glucose to fructose isomerization reaction was investigated. In addition, the frequency factors and the activation energies were determined by using Arrhenius-like expressions. Furthermore, correlations were found for the maximum reaction rate (i.e., Vm) and apparent Michaelis−Menten constant (i.e., Km). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800400b
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3271–3278[article] Kinetics of glucose isomerization to fructose by immobilized glucose isomerase (sweetzyme IT) [texte imprimé] / Asghar Molaei Dehkordi, Auteur ; Mehrdad Shoai Tehrany, Auteur ; Iman Safari, Auteur . - 2009 . - pp. 3271–3278.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3271–3278
Mots-clés : Immobilized glucose isomerase Stirred-tank reactor Fructose isomerization reaction Arrhenius-like expressions Résumé : We present the kinetic parameters and equilibrium constant of the enzymatic glucose−fructose isomerization reaction with an immobilized glucose isomerase (IGI), Sweetzyme IT, using a batch stirred-tank reactor following the procedure developed by Dehkordi et al. ( AIChE J. 2008, 54, 1333). The model predictions were compared with the experimental data and fair agreements were found. The influence of temperature on the equilibrium constant and kinetic parameters of glucose to fructose isomerization reaction was investigated. In addition, the frequency factors and the activation energies were determined by using Arrhenius-like expressions. Furthermore, correlations were found for the maximum reaction rate (i.e., Vm) and apparent Michaelis−Menten constant (i.e., Km). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800400b Exemplaires
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Titre : Low-pressure packed-bed gas-phase dehydration of glycerol to acrolein Type de document : texte imprimé Auteurs : Yan, Wei, Auteur ; Galen J. Suppes, Auteur Année de publication : 2009 Article en page(s) : pp. 3279–3283 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Glycerol Gas-phase dehydration Solid acid catalysts Résumé : Glycerol has become readily available from biodiesel industry. High functionality and relatively low price make it a potential building block to produce value-added derivatives such as acrolein. In this study, low-pressure packed-bed gas-phase dehydration of glycerol was investigated in presence of various solid acid catalysts, including H3PO4/activated carbon catalyst. Dehydration mechanism over H3PO4/activated carbon catalyst was validated. In the presence of H3PO4/activated carbon catalyst, yield of acroelin (66.8%) and selectivity to acrolein (84.0%) were achieved at the temperature of 260 °C and the pressure of 0.85 bar. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801200p
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3279–3283[article] Low-pressure packed-bed gas-phase dehydration of glycerol to acrolein [texte imprimé] / Yan, Wei, Auteur ; Galen J. Suppes, Auteur . - 2009 . - pp. 3279–3283.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3279–3283
Mots-clés : Glycerol Gas-phase dehydration Solid acid catalysts Résumé : Glycerol has become readily available from biodiesel industry. High functionality and relatively low price make it a potential building block to produce value-added derivatives such as acrolein. In this study, low-pressure packed-bed gas-phase dehydration of glycerol was investigated in presence of various solid acid catalysts, including H3PO4/activated carbon catalyst. Dehydration mechanism over H3PO4/activated carbon catalyst was validated. In the presence of H3PO4/activated carbon catalyst, yield of acroelin (66.8%) and selectivity to acrolein (84.0%) were achieved at the temperature of 260 °C and the pressure of 0.85 bar. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801200p Exemplaires
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Titre : Single-event microkinetic model for long-chain paraffin hydrocracking and hydroisomerization on an amorphous Pt/SiO2·Al2O3 catalyst Type de document : texte imprimé Auteurs : Marios Mitsios, Auteur ; Denis Guillaume, Auteur ; Pierre Galtier, Auteur Année de publication : 2009 Article en page(s) : pp. 3284–3292 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Single-event microkinetic concept Acid-catalyzed reactions Paraffin hydrocracking Résumé : Hydrocracking of a long-chain paraffin, n-hexadecane, was carried out on an amorphous Pt/SiO2·Al2O3 bifunctional catalyst. Through an isomerization selectivity analysis, it was found that the behavior of the system approaches the ideal hydrocracking conditions. The kinetic modeling of paraffin hydrocracking and hydroisomerization was realized by using the principles of the single-event microkinetic concept. The single-event microkinetic concept has been demonstrated to be efficient in the modeling of acid-catalyzed reactions. A lumped single-event microkinetic model was developed for heavy paraffin hydrocracking in the liquid phase, which considers a group of only nine rate constants for the reactions on the acid phase of the catalyst. The model’s lumping coefficients were calculated by the lateral-chain method, a computer-based approach that does not imply the generation of the whole reaction network. The rate constants were estimated at 340 °C from n-hexadecane hydroisomerization experiments in a plug-flow pilot reactor. The kinetic model was validated (upon extrapolation) by the simulation of two heavier paraffin feeds: a C20−C30 wax mixture and pure squalane. The agreement between the calculated and experimental data was satisfactory. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800974q
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3284–3292[article] Single-event microkinetic model for long-chain paraffin hydrocracking and hydroisomerization on an amorphous Pt/SiO2·Al2O3 catalyst [texte imprimé] / Marios Mitsios, Auteur ; Denis Guillaume, Auteur ; Pierre Galtier, Auteur . - 2009 . - pp. 3284–3292.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3284–3292
Mots-clés : Single-event microkinetic concept Acid-catalyzed reactions Paraffin hydrocracking Résumé : Hydrocracking of a long-chain paraffin, n-hexadecane, was carried out on an amorphous Pt/SiO2·Al2O3 bifunctional catalyst. Through an isomerization selectivity analysis, it was found that the behavior of the system approaches the ideal hydrocracking conditions. The kinetic modeling of paraffin hydrocracking and hydroisomerization was realized by using the principles of the single-event microkinetic concept. The single-event microkinetic concept has been demonstrated to be efficient in the modeling of acid-catalyzed reactions. A lumped single-event microkinetic model was developed for heavy paraffin hydrocracking in the liquid phase, which considers a group of only nine rate constants for the reactions on the acid phase of the catalyst. The model’s lumping coefficients were calculated by the lateral-chain method, a computer-based approach that does not imply the generation of the whole reaction network. The rate constants were estimated at 340 °C from n-hexadecane hydroisomerization experiments in a plug-flow pilot reactor. The kinetic model was validated (upon extrapolation) by the simulation of two heavier paraffin feeds: a C20−C30 wax mixture and pure squalane. The agreement between the calculated and experimental data was satisfactory. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800974q Exemplaires
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Titre : Investigation of batch alkene epoxidations catalyzed by polymer-supported Mo(VI) complexes Type de document : texte imprimé Auteurs : Krzysztof Ambroziak, Auteur ; Rene Mbeleck, Auteur ; Yue He, Auteur Année de publication : 2009 Article en page(s) : pp. 3293–3302 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Polymer-supported Mo(VI) catalysts Alkenes Cyclohexene epoxidation Résumé : Polymer-supported Mo(VI) catalysts (PBI.Mo and Ps.AMP.Mo) have been prepared and characterized. The activities of both of these catalysts in epoxidation of alkenes (e.g., cyclohexene; 1-octene; limonene; α-pinene) with dry tert-butyl hydroperoxide (TBHP) as oxidant have been studied under different reaction conditions in a batch reactor. The long-term stability and Mo leaching of each polymer catalyst was also assessed by recycling a sample in batch reaction using conditions that will form the basis of a continuous process. Both catalysts have been shown to be sufficiently stable to be considered as real candidates for use in such a process. In the case of the PBI.Mo catalyst, the order of reactivity of the alkenes was found to be the following: cyclohexene > limonene > α-pinene > 1-octene. “Wet” TBHP can also be used for cyclohexene epoxidation catalyzed by PBI.Mo without any significant decrease in the final TBHP conversion. In the case of limonene epoxidation, however, the presence of water reduced the TBHP conversion and also affected the cis−trans ratio of the main product 1,2-limonene epoxide. The reusability studies with PBI.Mo revealed that the largest fall in the final TBHP conversion was observed for α-pinene epoxidation among the alkenes studied. For 1-octene epoxidation, the loss of Mo from each support has been investigated by isolating any residue from the reaction supernatant solutions, following removal of the heterogeneous polymer catalyst, and then using the residues as potential catalysts in epoxidation reactions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801171s
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3293–3302[article] Investigation of batch alkene epoxidations catalyzed by polymer-supported Mo(VI) complexes [texte imprimé] / Krzysztof Ambroziak, Auteur ; Rene Mbeleck, Auteur ; Yue He, Auteur . - 2009 . - pp. 3293–3302.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3293–3302
Mots-clés : Polymer-supported Mo(VI) catalysts Alkenes Cyclohexene epoxidation Résumé : Polymer-supported Mo(VI) catalysts (PBI.Mo and Ps.AMP.Mo) have been prepared and characterized. The activities of both of these catalysts in epoxidation of alkenes (e.g., cyclohexene; 1-octene; limonene; α-pinene) with dry tert-butyl hydroperoxide (TBHP) as oxidant have been studied under different reaction conditions in a batch reactor. The long-term stability and Mo leaching of each polymer catalyst was also assessed by recycling a sample in batch reaction using conditions that will form the basis of a continuous process. Both catalysts have been shown to be sufficiently stable to be considered as real candidates for use in such a process. In the case of the PBI.Mo catalyst, the order of reactivity of the alkenes was found to be the following: cyclohexene > limonene > α-pinene > 1-octene. “Wet” TBHP can also be used for cyclohexene epoxidation catalyzed by PBI.Mo without any significant decrease in the final TBHP conversion. In the case of limonene epoxidation, however, the presence of water reduced the TBHP conversion and also affected the cis−trans ratio of the main product 1,2-limonene epoxide. The reusability studies with PBI.Mo revealed that the largest fall in the final TBHP conversion was observed for α-pinene epoxidation among the alkenes studied. For 1-octene epoxidation, the loss of Mo from each support has been investigated by isolating any residue from the reaction supernatant solutions, following removal of the heterogeneous polymer catalyst, and then using the residues as potential catalysts in epoxidation reactions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801171s Exemplaires
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Titre : Improvement of desulfurization performances of waste cement particles by acid treatment Type de document : texte imprimé Auteurs : Jiawei Wu, Auteur ; Atsushi Iizuka, Auteur ; Kazukiyo Kumagai, Auteur Année de publication : 2009 Article en page(s) : pp. 3303–3307 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Waste cement Desulfurization rate Acid treatments Résumé : We studied the effect of acid treatments on the desulfurization rate of waste cement, a byproduct in the recycling of aggregates from waste concrete. Calcium components in the waste cement were partially extracted by treatment with carbonic acid (aqueous solution of high-pressure CO2), hydrochloric acid, or acetic acid. The desulfurization rate was examined using a thermogravimetric method. The desulfurization rates in the initial stage of the reaction ( En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801312b
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3303–3307[article] Improvement of desulfurization performances of waste cement particles by acid treatment [texte imprimé] / Jiawei Wu, Auteur ; Atsushi Iizuka, Auteur ; Kazukiyo Kumagai, Auteur . - 2009 . - pp. 3303–3307.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3303–3307
Mots-clés : Waste cement Desulfurization rate Acid treatments Résumé : We studied the effect of acid treatments on the desulfurization rate of waste cement, a byproduct in the recycling of aggregates from waste concrete. Calcium components in the waste cement were partially extracted by treatment with carbonic acid (aqueous solution of high-pressure CO2), hydrochloric acid, or acetic acid. The desulfurization rate was examined using a thermogravimetric method. The desulfurization rates in the initial stage of the reaction ( En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801312b Exemplaires
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Titre : Study of optimal reaction conditions and a modified residue catalytic cracking process for maximizing liquid products Type de document : texte imprimé Auteurs : Gang Wang, Auteur ; Xing-ying Lan, Auteur ; Chun-ming Xu, Auteur Année de publication : 2009 Article en page(s) : pp. 3308–3316 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Residue fluid catalytic cracking Riser reactor Feedstock droplets Liquid products Résumé : The effect of residence time, catalyst-to-oil (CTO), and temperature of regenerated catalyst (TRC) on the product distribution of residue fluid catalytic cracking (RFCC) are investigated in a technical pilot scale riser apparatus. Under simulated realistic conditions, thermal cracking predominantly occurs at two different parts of the riser reactor: one is at the bottom of riser for hot catalyst contacting with relatively cool feedstock droplets and another is at the second half of the riser for deactivation of the catalyst. Therefore, the optimal reaction conditions and a modified RFCC process are proposed for lowering thermal cracking and maximizing liquid products. The simulation experiments of the modified process show that product distribution at lower TRC and higher CTO of the optimal conditions is superior to that of the routine RFCC at a nearly similar conversion level, more than 0.4−2.7 wt % liquid products could be obtained. The balance of hydrogen for the products indicates that the decrease of dry gas and coke at the optimal reaction conditions leads to more H of the feed is distributed into the liquid products. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8013555
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3308–3316[article] Study of optimal reaction conditions and a modified residue catalytic cracking process for maximizing liquid products [texte imprimé] / Gang Wang, Auteur ; Xing-ying Lan, Auteur ; Chun-ming Xu, Auteur . - 2009 . - pp. 3308–3316.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3308–3316
Mots-clés : Residue fluid catalytic cracking Riser reactor Feedstock droplets Liquid products Résumé : The effect of residence time, catalyst-to-oil (CTO), and temperature of regenerated catalyst (TRC) on the product distribution of residue fluid catalytic cracking (RFCC) are investigated in a technical pilot scale riser apparatus. Under simulated realistic conditions, thermal cracking predominantly occurs at two different parts of the riser reactor: one is at the bottom of riser for hot catalyst contacting with relatively cool feedstock droplets and another is at the second half of the riser for deactivation of the catalyst. Therefore, the optimal reaction conditions and a modified RFCC process are proposed for lowering thermal cracking and maximizing liquid products. The simulation experiments of the modified process show that product distribution at lower TRC and higher CTO of the optimal conditions is superior to that of the routine RFCC at a nearly similar conversion level, more than 0.4−2.7 wt % liquid products could be obtained. The balance of hydrogen for the products indicates that the decrease of dry gas and coke at the optimal reaction conditions leads to more H of the feed is distributed into the liquid products. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8013555 Exemplaires
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Titre : Adsorption and catalytic oxidation of gaseous elemental mercury in flue gas over MnOx/alumina Type de document : texte imprimé Auteurs : Shaohua Qiao, Auteur ; Chen, Jie, Auteur ; Jianfeng Li, Auteur Année de publication : 2009 Article en page(s) : pp. 3317–3322 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : MnOx/alumina catalysts Flue gas Hydrogen chloride Adsorption Résumé : MnOx/Al2O3 catalysts (i.e., impregnating manganese oxide on alumina) were employed to remove elemental mercury (Hg0) from flue gas. MnOx/Al2O3 was found to have significant adsorption performance on capturing Hg0 in the absence of hydrogen chloride (HCl), and its favorable adsorption temperature was about 600 K. However, the catalytic oxidation of Hg0 became dominant when HCl or chlorine (Cl2) was present in flue gas, and the removal efficiency of Hg0 was up to 90% with 20 ppm of HCl or 2 ppm of Cl2. In addition, the catalysts with adsorbed mercury could be chemically regenerated by rinsing with HCl gas to strip off the adsorbed mercury in the form of HgCl2. Sulfur dioxide displayed inhibition to the adsorption of Hg0on the catalysts, but the inhibition was less to the catalytic oxidation of Hg0, especially in the presence of Cl2. The analysis results of XPS and pyrolysis−AAS indicated that the adsorbed mercury was mainly in the forms of mercuric oxide (HgO) and the weakly bonded speciation, and the ratio of them varied with the adsorption amount and manganese content on catalysts. The multifunctional performances of MnOx/Al2O3 on the removal of Hg0 appeared to be promising in the industrial applications. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801478w
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3317–3322[article] Adsorption and catalytic oxidation of gaseous elemental mercury in flue gas over MnOx/alumina [texte imprimé] / Shaohua Qiao, Auteur ; Chen, Jie, Auteur ; Jianfeng Li, Auteur . - 2009 . - pp. 3317–3322.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3317–3322
Mots-clés : MnOx/alumina catalysts Flue gas Hydrogen chloride Adsorption Résumé : MnOx/Al2O3 catalysts (i.e., impregnating manganese oxide on alumina) were employed to remove elemental mercury (Hg0) from flue gas. MnOx/Al2O3 was found to have significant adsorption performance on capturing Hg0 in the absence of hydrogen chloride (HCl), and its favorable adsorption temperature was about 600 K. However, the catalytic oxidation of Hg0 became dominant when HCl or chlorine (Cl2) was present in flue gas, and the removal efficiency of Hg0 was up to 90% with 20 ppm of HCl or 2 ppm of Cl2. In addition, the catalysts with adsorbed mercury could be chemically regenerated by rinsing with HCl gas to strip off the adsorbed mercury in the form of HgCl2. Sulfur dioxide displayed inhibition to the adsorption of Hg0on the catalysts, but the inhibition was less to the catalytic oxidation of Hg0, especially in the presence of Cl2. The analysis results of XPS and pyrolysis−AAS indicated that the adsorbed mercury was mainly in the forms of mercuric oxide (HgO) and the weakly bonded speciation, and the ratio of them varied with the adsorption amount and manganese content on catalysts. The multifunctional performances of MnOx/Al2O3 on the removal of Hg0 appeared to be promising in the industrial applications. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801478w Exemplaires
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Titre : Soot combustion dynamics in a planar diesel particulate filter Type de document : texte imprimé Auteurs : K. Chen, Auteur ; K. S. Martirosyan, Auteur ; D. Luss, Auteur Année de publication : 2009 Article en page(s) : pp. 3323–3330 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Soot combustion Diesel particulate filter Oxygen concentrations IR imaging Résumé : The dynamic features of soot combustion on a single layer, planar diesel particulate filter (DPF) were studied using IR imaging. At a feed temperature of 635 °C, the soot combustion rate was uniform all over the surface at low oxygen concentrations. At higher oxygen concentrations, local ignition occurred at either one or several locations. The maximum temperature rise of the moving fronts (>100 °C) was much higher than those attained during uniform combustion. The temperature fronts bounding an ignited zone propagated on the surface. Their peak temperature and velocity changed as they moved on the surface. The maximum temperature of a downstream moving front exceeded that of the corresponding one moving upstream. At a soot loading of 10 g/L, a hot zone formed close to the end of the DPF and the bounding temperature front propagated upstream until it conquered the whole surface. At a soot loading of 20 g/L, the position and number of the hot zones strongly depended on the oxygen concentration. In general, increasing either the oxygen concentration or the soot load increased the moving front temperature and velocity. The flow rate affected the location of the ignition point for soot loading of 10 g/L but not for 20 g/L. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8015544
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3323–3330[article] Soot combustion dynamics in a planar diesel particulate filter [texte imprimé] / K. Chen, Auteur ; K. S. Martirosyan, Auteur ; D. Luss, Auteur . - 2009 . - pp. 3323–3330.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3323–3330
Mots-clés : Soot combustion Diesel particulate filter Oxygen concentrations IR imaging Résumé : The dynamic features of soot combustion on a single layer, planar diesel particulate filter (DPF) were studied using IR imaging. At a feed temperature of 635 °C, the soot combustion rate was uniform all over the surface at low oxygen concentrations. At higher oxygen concentrations, local ignition occurred at either one or several locations. The maximum temperature rise of the moving fronts (>100 °C) was much higher than those attained during uniform combustion. The temperature fronts bounding an ignited zone propagated on the surface. Their peak temperature and velocity changed as they moved on the surface. The maximum temperature of a downstream moving front exceeded that of the corresponding one moving upstream. At a soot loading of 10 g/L, a hot zone formed close to the end of the DPF and the bounding temperature front propagated upstream until it conquered the whole surface. At a soot loading of 20 g/L, the position and number of the hot zones strongly depended on the oxygen concentration. In general, increasing either the oxygen concentration or the soot load increased the moving front temperature and velocity. The flow rate affected the location of the ignition point for soot loading of 10 g/L but not for 20 g/L. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8015544 Exemplaires
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Titre : Long-term deactivation of a commercial CoMo/γ-Al2O3 catalyst in hydrodesulfurization of a naphtha stream Type de document : texte imprimé Auteurs : Morteza Baghalha, Auteur ; Seyed Mohammad Hosseini, Auteur Année de publication : 2009 Article en page(s) : pp. 3331–3340 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : CoMo/γ -Al2O3 catalyst Naphtha stream Hydrodesulfurization Fixed bed reactor Résumé : Long-term deactivation of a commercial CoMo/γ-Al2O3 catalyst used in the hydrodesulfurization of a naphtha stream was studied using 35 months of operating data of an industrial HDS fixed bed reactor. The major sulfur-containing species of the naphtha feed was identified as 2-ethyl-4-methylthiophene (2E4MT) based on GC-MS analysis. The characterization of the industrial catalysts was performed by BET, XRD, XRF, and HCN Leco analyses. The reaction rate constant of the gas-phase hydrodesulfurization reaction was calculated by fitting the industrial reactor conversion data to the Hougen−Watson rate equation, assuming that the surface reaction between the sulfur-containing species and adsorbed hydrogen is the rate-determining step. The effectiveness factor was ∼0.91, nearly constant along the catalyst bed, implicitly implying that the HDS reaction is approximately first order in 2E4MT concentration. From the combined kinetics and characterization analyses, it was found that the main mechanisms of deactivation of the commercial HDS catalysts were (1) sulfur loss and coke deposition (recoverable by regeneration) and (2) Co−Mo−S permanent loss of activity. After 7 months of operation (before the first regeneration), the share of each deactivation mechanism in the loss of activity is (1) 81% and (2) 19%. The Co−Mo−S permanent loss of activity is assumed to be caused by arsenic poisoning, Co reaction with the alumina matrix, and decrease in the catalytic active surface area. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801743v
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3331–3340[article] Long-term deactivation of a commercial CoMo/γ-Al2O3 catalyst in hydrodesulfurization of a naphtha stream [texte imprimé] / Morteza Baghalha, Auteur ; Seyed Mohammad Hosseini, Auteur . - 2009 . - pp. 3331–3340.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3331–3340
Mots-clés : CoMo/γ -Al2O3 catalyst Naphtha stream Hydrodesulfurization Fixed bed reactor Résumé : Long-term deactivation of a commercial CoMo/γ-Al2O3 catalyst used in the hydrodesulfurization of a naphtha stream was studied using 35 months of operating data of an industrial HDS fixed bed reactor. The major sulfur-containing species of the naphtha feed was identified as 2-ethyl-4-methylthiophene (2E4MT) based on GC-MS analysis. The characterization of the industrial catalysts was performed by BET, XRD, XRF, and HCN Leco analyses. The reaction rate constant of the gas-phase hydrodesulfurization reaction was calculated by fitting the industrial reactor conversion data to the Hougen−Watson rate equation, assuming that the surface reaction between the sulfur-containing species and adsorbed hydrogen is the rate-determining step. The effectiveness factor was ∼0.91, nearly constant along the catalyst bed, implicitly implying that the HDS reaction is approximately first order in 2E4MT concentration. From the combined kinetics and characterization analyses, it was found that the main mechanisms of deactivation of the commercial HDS catalysts were (1) sulfur loss and coke deposition (recoverable by regeneration) and (2) Co−Mo−S permanent loss of activity. After 7 months of operation (before the first regeneration), the share of each deactivation mechanism in the loss of activity is (1) 81% and (2) 19%. The Co−Mo−S permanent loss of activity is assumed to be caused by arsenic poisoning, Co reaction with the alumina matrix, and decrease in the catalytic active surface area. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801743v Exemplaires
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Titre : Dynamic liquid saturation in a trickle bed reactor involving Newtonian/non-Newtonian liquid phase Type de document : texte imprimé Auteurs : Ajay Bansal, Auteur ; S. K. Sharma, Auteur Année de publication : 2009 Article en page(s) : pp. 3341–3350 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Dynamic liquid saturation Trickle bed reactor Newtonian phase Liquid flow rates Non-Newtonian viscoelastic fluids Résumé : Dynamic liquid saturation is an important hydrodynamic parameter that affects the performance of a trickle bed reactor. The parameters that affect the dynamic liquid saturation, by using Newtonian liquid phase, include gas and liquid flow rates, surface tension and viscosity of the liquid phase, and bed configurations. Additional rheological parameters affecting dynamic liquid saturation, in case of non-Newtonian viscoinelastic liquids, are observed to be flow consistency index K and flow behavior index n. The effect of viscoelasticity, in case of non-Newtonian viscoelastic fluids, was investigated in terms of Weissenberg number. A set of 20 correlations were selected from the literature to see the applicability of these correlations under varied conditions of bed configurations and liquid-phase properties as studied in the present investigation. It was observed that the correlations are valid only for a restricted range of parameters and none of the correlations seem to be applicable over the entire range of parameters as investigated in the present study. On the basis of the experimental data obtained, correlations are first developed for Newtonian liquids. These correlations could reproduce the literature data satisfactorily to ±20%. Further, the correlations developed are extended to predict dynamic liquid saturation for viscoinelastic and viscoelastic liquid phases. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801399u
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3341–3350[article] Dynamic liquid saturation in a trickle bed reactor involving Newtonian/non-Newtonian liquid phase [texte imprimé] / Ajay Bansal, Auteur ; S. K. Sharma, Auteur . - 2009 . - pp. 3341–3350.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3341–3350
Mots-clés : Dynamic liquid saturation Trickle bed reactor Newtonian phase Liquid flow rates Non-Newtonian viscoelastic fluids Résumé : Dynamic liquid saturation is an important hydrodynamic parameter that affects the performance of a trickle bed reactor. The parameters that affect the dynamic liquid saturation, by using Newtonian liquid phase, include gas and liquid flow rates, surface tension and viscosity of the liquid phase, and bed configurations. Additional rheological parameters affecting dynamic liquid saturation, in case of non-Newtonian viscoinelastic liquids, are observed to be flow consistency index K and flow behavior index n. The effect of viscoelasticity, in case of non-Newtonian viscoelastic fluids, was investigated in terms of Weissenberg number. A set of 20 correlations were selected from the literature to see the applicability of these correlations under varied conditions of bed configurations and liquid-phase properties as studied in the present investigation. It was observed that the correlations are valid only for a restricted range of parameters and none of the correlations seem to be applicable over the entire range of parameters as investigated in the present study. On the basis of the experimental data obtained, correlations are first developed for Newtonian liquids. These correlations could reproduce the literature data satisfactorily to ±20%. Further, the correlations developed are extended to predict dynamic liquid saturation for viscoinelastic and viscoelastic liquid phases. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801399u Exemplaires
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Titre : Kinetics of 4-chlorophenol hydrodechlorination with alumina and activated carbon-supported Pd and Rh catalysts Type de document : texte imprimé Auteurs : Elena Díaz, Auteur ; José A. Casas, Auteur ; Ángel F. Mohedano, Auteur Année de publication : 2009 Article en page(s) : pp. 3351–3358 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : 4-chlorophenol Hydrodechlorination Y-alumina Stirred basket reactor Résumé : The hydrodechlorination of 4-chlorophenol promoted by different commercial catalysts based on Pd and Rh on γ-alumina and activated carbon has been investigated in a continuous stirred basket reactor (20−40 °C and 1 bar) in order to analyze the kinetics of the reaction. External and internal mass transfer effects were found to be negligible from the values of the Carberry and Weisz−Prater numbers. The reaction rate showed a first-order dependence with respect to 4-chlorophenol. All catalysts were effective in the removal of 4-chlorophenol, with phenol, cyclohexanone, and cyclohexanol identified as reaction products, although the last one was only detected with the Rh/AC catalyst. The highest apparent kinetic constant values correspond to the hydrogenation of 4-chlorophenol to phenol. These values were in the range 146−478 L/kgcat·h for Pd/Al2O3, 179−713 L/kgcat·h for Pd/AC, and 44−172 L/kgcat·h for Rh/AC. The values of the apparent activation energy for 4-chlorophenol disappearance ranged within 47−58 kJ/mol. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801462b
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3351–3358[article] Kinetics of 4-chlorophenol hydrodechlorination with alumina and activated carbon-supported Pd and Rh catalysts [texte imprimé] / Elena Díaz, Auteur ; José A. Casas, Auteur ; Ángel F. Mohedano, Auteur . - 2009 . - pp. 3351–3358.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3351–3358
Mots-clés : 4-chlorophenol Hydrodechlorination Y-alumina Stirred basket reactor Résumé : The hydrodechlorination of 4-chlorophenol promoted by different commercial catalysts based on Pd and Rh on γ-alumina and activated carbon has been investigated in a continuous stirred basket reactor (20−40 °C and 1 bar) in order to analyze the kinetics of the reaction. External and internal mass transfer effects were found to be negligible from the values of the Carberry and Weisz−Prater numbers. The reaction rate showed a first-order dependence with respect to 4-chlorophenol. All catalysts were effective in the removal of 4-chlorophenol, with phenol, cyclohexanone, and cyclohexanol identified as reaction products, although the last one was only detected with the Rh/AC catalyst. The highest apparent kinetic constant values correspond to the hydrogenation of 4-chlorophenol to phenol. These values were in the range 146−478 L/kgcat·h for Pd/Al2O3, 179−713 L/kgcat·h for Pd/AC, and 44−172 L/kgcat·h for Rh/AC. The values of the apparent activation energy for 4-chlorophenol disappearance ranged within 47−58 kJ/mol. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801462b Exemplaires
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Titre : Influences of the chemical state of alkaline compounds and the nature of alkali metal on wood pyrolysis Type de document : texte imprimé Auteurs : Colomba Di Blasi, Auteur ; Antonio Galgano, Auteur ; Carmen Branca, Auteur Année de publication : 2009 Article en page(s) : pp. 3359–3369 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Alkaline compounds Wood pyrolysis Hydroxypropanone Minor carbohydrate Résumé : Motivated by the production of compounds of good industrial value, pyrolysis of fir wood catalyzed by alkaline compounds (NaOH, KOH, Na2CO3, K2CO3, KC2H3O2, and NaCl) has been investigated. Catalysts have been impregnated in wood (preliminarily extracted with water) by means of aqueous solutions resulting in concentrations of the K or Na ion in wood of about 0.37−0.41%. Pyrolysis experiments have been done with a fixed-bed reactor preheated at 800 K.The decomposition process is anticipated at lower temperatures with conversion times from 2.5 (NaOH) to 1.7 (NaCl) times shorter. Formation of char, carbon dioxide, and water is favored with total yields between 70 and 61% versus 48% of extracted wood (dry sample mass basis). The yields of carbon monoxide are increased approximately from 4% to 6% while the yields of organic compounds are lowered to 19−29% (versus 43%) with the disappearance of sugar compounds and a strong diminution in other typical products of uncatalyzed wood pyrolysis but hydroxypropanone. However, sodium and potassium hydroxides increase the yields of some minor carbohydrate compounds (1-hydroxy-2butanone, 2-methyl-2-cyclopentenone, 3-ethyl-2-hydroxy-2-cyclopentenone, and 3-methyl-2-cyclopentenone) by factors of 4−6 (yields of about 0.8−0.12%). The yields of total phenols are also increased. In particular, NaOH is slightly more effective for the production of guaiacol, cresols, and 4-ethylguaicol (factors of increase between 3 and 4 with yields of 0.3−1.2%), whereas KOH is slightly better for the production of phenol, cis-isoeugenol and trans-isoeugenol (factor of increase of 2−6 with yields between 0.7 and 0.2%). Finally, the production of furfuryl alcohol can be augmented up to factors of about 15 by potassium hydroxide or carbonate (yields up to 0.6%). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801468y
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3359–3369[article] Influences of the chemical state of alkaline compounds and the nature of alkali metal on wood pyrolysis [texte imprimé] / Colomba Di Blasi, Auteur ; Antonio Galgano, Auteur ; Carmen Branca, Auteur . - 2009 . - pp. 3359–3369.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3359–3369
Mots-clés : Alkaline compounds Wood pyrolysis Hydroxypropanone Minor carbohydrate Résumé : Motivated by the production of compounds of good industrial value, pyrolysis of fir wood catalyzed by alkaline compounds (NaOH, KOH, Na2CO3, K2CO3, KC2H3O2, and NaCl) has been investigated. Catalysts have been impregnated in wood (preliminarily extracted with water) by means of aqueous solutions resulting in concentrations of the K or Na ion in wood of about 0.37−0.41%. Pyrolysis experiments have been done with a fixed-bed reactor preheated at 800 K.The decomposition process is anticipated at lower temperatures with conversion times from 2.5 (NaOH) to 1.7 (NaCl) times shorter. Formation of char, carbon dioxide, and water is favored with total yields between 70 and 61% versus 48% of extracted wood (dry sample mass basis). The yields of carbon monoxide are increased approximately from 4% to 6% while the yields of organic compounds are lowered to 19−29% (versus 43%) with the disappearance of sugar compounds and a strong diminution in other typical products of uncatalyzed wood pyrolysis but hydroxypropanone. However, sodium and potassium hydroxides increase the yields of some minor carbohydrate compounds (1-hydroxy-2butanone, 2-methyl-2-cyclopentenone, 3-ethyl-2-hydroxy-2-cyclopentenone, and 3-methyl-2-cyclopentenone) by factors of 4−6 (yields of about 0.8−0.12%). The yields of total phenols are also increased. In particular, NaOH is slightly more effective for the production of guaiacol, cresols, and 4-ethylguaicol (factors of increase between 3 and 4 with yields of 0.3−1.2%), whereas KOH is slightly better for the production of phenol, cis-isoeugenol and trans-isoeugenol (factor of increase of 2−6 with yields between 0.7 and 0.2%). Finally, the production of furfuryl alcohol can be augmented up to factors of about 15 by potassium hydroxide or carbonate (yields up to 0.6%). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801468y Exemplaires
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Titre : Degradation and mineralization of organic pollutants contained in actual pulp and paper mill wastewaters by a UV/H2O2 process Type de document : texte imprimé Auteurs : Bedoui Ahmed, Auteur ; Mohamed Hasni, Auteur ; Elalaoui Limem, Auteur Année de publication : 2009 Article en page(s) : pp. 3370–3379 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : UV/H2O2 treatment Wastewaters Chemical oxygen demand Total organic carbon Carboxylic acids Résumé : In this work, UV/H2O2 treatment of actual pulp and paper mill wastewater (PPMW) was investigated. To determine optimal conditions, the effects of some experimental parameters (initial pH, initial H2O2 concentration, temperature, and organics load) on the UV/H2O2 process efficiency in terms of absorbance at 330 and 281 nm and chemical oxygen demand (COD) and total organic carbon (TOC) removals were studied. The results show that the UV/H2O2 system leads successfully to the almost-complete elimination of absorbance at 330 and 281 nm, COD, and TOC from an actual PPMW containing 270 mg of C L−1 under natural pH (pH 11.25) using 2.1 g of H2O2 L−1 at 28 °C. Under these optimal conditions, pseudo-first-order kinetics was determined for absorbance at 330 and 281 nm and COD decay with rate constants of 0.029, 0.02, and 0.008 min−1, respectively. Furthermore, the evolution with time of the H2O2 concentration exhibits two parts: a linear decrease to 300 min and then exponential change until the end of the treatment. This shows that the kinetics of H2O2 disappearance changes during the treatment from a pseudo-zeroth-order reaction in the first steps to a pseudo-first-order reaction in the final steps. On the other hand, a continuous decrease of pH and a rapid total phenols disappearance were observed during UV/H2O2 treatment of PPMW. These results suggest that several steps are involved in the photochemical oxidation of organics, starting with degradation of lignin derivatives and tannins to obtain aromatic intermediates that then undergo oxidative ring opening, leading to aliphatic carboxylic acids. In the final steps, carboxylic acids are mineralized into CO2 and H2O. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801755u
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3370–3379[article] Degradation and mineralization of organic pollutants contained in actual pulp and paper mill wastewaters by a UV/H2O2 process [texte imprimé] / Bedoui Ahmed, Auteur ; Mohamed Hasni, Auteur ; Elalaoui Limem, Auteur . - 2009 . - pp. 3370–3379.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3370–3379
Mots-clés : UV/H2O2 treatment Wastewaters Chemical oxygen demand Total organic carbon Carboxylic acids Résumé : In this work, UV/H2O2 treatment of actual pulp and paper mill wastewater (PPMW) was investigated. To determine optimal conditions, the effects of some experimental parameters (initial pH, initial H2O2 concentration, temperature, and organics load) on the UV/H2O2 process efficiency in terms of absorbance at 330 and 281 nm and chemical oxygen demand (COD) and total organic carbon (TOC) removals were studied. The results show that the UV/H2O2 system leads successfully to the almost-complete elimination of absorbance at 330 and 281 nm, COD, and TOC from an actual PPMW containing 270 mg of C L−1 under natural pH (pH 11.25) using 2.1 g of H2O2 L−1 at 28 °C. Under these optimal conditions, pseudo-first-order kinetics was determined for absorbance at 330 and 281 nm and COD decay with rate constants of 0.029, 0.02, and 0.008 min−1, respectively. Furthermore, the evolution with time of the H2O2 concentration exhibits two parts: a linear decrease to 300 min and then exponential change until the end of the treatment. This shows that the kinetics of H2O2 disappearance changes during the treatment from a pseudo-zeroth-order reaction in the first steps to a pseudo-first-order reaction in the final steps. On the other hand, a continuous decrease of pH and a rapid total phenols disappearance were observed during UV/H2O2 treatment of PPMW. These results suggest that several steps are involved in the photochemical oxidation of organics, starting with degradation of lignin derivatives and tannins to obtain aromatic intermediates that then undergo oxidative ring opening, leading to aliphatic carboxylic acids. In the final steps, carboxylic acids are mineralized into CO2 and H2O. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801755u Exemplaires
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Titre : Kinetics of the chemical oxidation of the pharmaceuticals primidone, ketoprofen, and diatrizoate in ultrapure and natural waters Type de document : texte imprimé Auteurs : Francisco J. Real, Auteur ; F. Javier Benitez, Auteur ; Juan L. Acero, Auteur Année de publication : 2009 Article en page(s) : pp. 3380–3388 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Oxidation processes systems Kinetic model Natural water Résumé : Oxidation of three pharmaceuticals (primidone, ketoprofen, and diatrizoate sodium) by means of several advanced oxidation processes including such as ozonation, UV radiation, and Fenton’s reagent has been studied. The influence of operating variables was established, and first-order rate constants were determined in most of the oxidation systems. Specifically, for the reactions with ozone, the following rate constants were obtained by means of a competition kinetic model: 1.0 ± 0.1, 0.40 ± 0.07, and 0.05 ± 0.01 M−1·s−1, for primidone, ketoprofen, and diatrizoate, respectively. The results showed that reaction with OH radicals was the major pathway for the oxidative transformation of these compounds. In the photodegradation experiments by 254 nm radiation, the quantum yields were also determined for every compound at different pH and temperatures. Additionally, the competition kinetic model, which was also used in Fenton’s reagent experiments, allowed to evaluate the rate constants for the reaction with hydroxyl radicals whose values were the following: (6.7 ± 0.2) × 109 M−1·s−1 for primidone, (8.4 ± 0.3) × 109 M−1·s−1 for ketoprofen, and (5.4 ± 0.3) × 108 M−1·s−1 for diatrizoate. Furthermore, the simultaneous oxidation of these selected pharmaceuticals in some natural water systems (a commercial mineral water, a groundwater, and surface water from a reservoir) was studied. The influence of the operating conditions on the removal efficiency was established. Finally, a kinetic model was proposed for the prediction of the elimination of the selected pharmaceuticals by ozone in these natural waters, with theoretical results that agreed well with the experimental ones. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801762p
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3380–3388[article] Kinetics of the chemical oxidation of the pharmaceuticals primidone, ketoprofen, and diatrizoate in ultrapure and natural waters [texte imprimé] / Francisco J. Real, Auteur ; F. Javier Benitez, Auteur ; Juan L. Acero, Auteur . - 2009 . - pp. 3380–3388.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3380–3388
Mots-clés : Oxidation processes systems Kinetic model Natural water Résumé : Oxidation of three pharmaceuticals (primidone, ketoprofen, and diatrizoate sodium) by means of several advanced oxidation processes including such as ozonation, UV radiation, and Fenton’s reagent has been studied. The influence of operating variables was established, and first-order rate constants were determined in most of the oxidation systems. Specifically, for the reactions with ozone, the following rate constants were obtained by means of a competition kinetic model: 1.0 ± 0.1, 0.40 ± 0.07, and 0.05 ± 0.01 M−1·s−1, for primidone, ketoprofen, and diatrizoate, respectively. The results showed that reaction with OH radicals was the major pathway for the oxidative transformation of these compounds. In the photodegradation experiments by 254 nm radiation, the quantum yields were also determined for every compound at different pH and temperatures. Additionally, the competition kinetic model, which was also used in Fenton’s reagent experiments, allowed to evaluate the rate constants for the reaction with hydroxyl radicals whose values were the following: (6.7 ± 0.2) × 109 M−1·s−1 for primidone, (8.4 ± 0.3) × 109 M−1·s−1 for ketoprofen, and (5.4 ± 0.3) × 108 M−1·s−1 for diatrizoate. Furthermore, the simultaneous oxidation of these selected pharmaceuticals in some natural water systems (a commercial mineral water, a groundwater, and surface water from a reservoir) was studied. The influence of the operating conditions on the removal efficiency was established. Finally, a kinetic model was proposed for the prediction of the elimination of the selected pharmaceuticals by ozone in these natural waters, with theoretical results that agreed well with the experimental ones. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801762p Exemplaires
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Titre : Computational method for efficient screening of metal precursors for nanomaterial syntheses Type de document : texte imprimé Auteurs : Yuuichi Orimoto, Auteur ; Ayumi Toyota, Auteur ; Takeshi Furuya, Auteur Année de publication : 2009 Article en page(s) : pp. 3389–3397 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Density functional theory Efficient screening Metal precursors Nanomaterial syntheses Résumé : A density functional theory (DFT) based method is proposed for efficient screening of metal precursors for nanomaterial syntheses. For this study, we examined the effectiveness of our DFT approach for predicting bulk properties of precursor metal complexes, which is a key of our method. The DFT calculations were applied for a series of copper(II) β-diketonate complexes to estimate values related to complex stabilities such as complex formation energies ΔEtotalcomplex, total energy changes for two-electron reduction ΔEtotalreduction, and so on. The value of ΔEtotalcomplex was compared to the stability constant β2 collected from the relevant literature; ΔEtotalreduction was compared with reduction potentials measured using cyclic voltammetry. Results obtained from these comparisons revealed that simple DFT calculations predicted the trend of the complex stabilities that were determined experimentally as a bulk property. Our method can predict precursor properties and can greatly contribute to efficient precursor selection for nanomaterial synthesis. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800903h
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3389–3397[article] Computational method for efficient screening of metal precursors for nanomaterial syntheses [texte imprimé] / Yuuichi Orimoto, Auteur ; Ayumi Toyota, Auteur ; Takeshi Furuya, Auteur . - 2009 . - pp. 3389–3397.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3389–3397
Mots-clés : Density functional theory Efficient screening Metal precursors Nanomaterial syntheses Résumé : A density functional theory (DFT) based method is proposed for efficient screening of metal precursors for nanomaterial syntheses. For this study, we examined the effectiveness of our DFT approach for predicting bulk properties of precursor metal complexes, which is a key of our method. The DFT calculations were applied for a series of copper(II) β-diketonate complexes to estimate values related to complex stabilities such as complex formation energies ΔEtotalcomplex, total energy changes for two-electron reduction ΔEtotalreduction, and so on. The value of ΔEtotalcomplex was compared to the stability constant β2 collected from the relevant literature; ΔEtotalreduction was compared with reduction potentials measured using cyclic voltammetry. Results obtained from these comparisons revealed that simple DFT calculations predicted the trend of the complex stabilities that were determined experimentally as a bulk property. Our method can predict precursor properties and can greatly contribute to efficient precursor selection for nanomaterial synthesis. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800903h Exemplaires
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Titre : Fabrication and evaluation of mesoporous poly(vinyl alcohol)-based activated carbon fibers Type de document : texte imprimé Auteurs : Hui-Min Feng, Auteur ; Shu-Juan Zhang, Auteur ; Yong-Zhen Chen, Auteur Année de publication : 2009 Article en page(s) : pp. 3398–3402 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Activated carbon fibers Mesoporous poly(vinyl alcohol) Raman spectroscopy Résumé : Poly(vinyl alcohol)- (PVA-) based activated carbon fibers (ACFs) with a high mesoporosity have been fabricated. The surface area and pore size distribution were fine-tuned by the careful control of the activation temperature and time. A mesopore volume fraction of 66% was obtained by activation at 1173 K for 120 min or 1273 K for 90 min. Raman spectroscopy revealed that more defect sites in the graphitic structure were found in samples with higher mesoporosity. Adsorption experiments demonstrated that the PVA-ACFs exhibited good adsorption capacities for both small-molecular-size iodine and the larger-size methylene blue, with adsorption capacities of up to 1934 and 709 mg/g, respectively. The adsorption kinetics of methylene blue on the PVA-ACFs was simulated by both a pseudo-second-order kinetic model and an intraparticle diffusion model. With an increase in mesoporosity, rate limitations on adsorption due to intraparticle diffusion were dramatically reduced. This resulted in an increase of up to a factor of 7 in the adsorption rate compared to that on microporous PVA-based ACFs. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8012852
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3398–3402[article] Fabrication and evaluation of mesoporous poly(vinyl alcohol)-based activated carbon fibers [texte imprimé] / Hui-Min Feng, Auteur ; Shu-Juan Zhang, Auteur ; Yong-Zhen Chen, Auteur . - 2009 . - pp. 3398–3402.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3398–3402
Mots-clés : Activated carbon fibers Mesoporous poly(vinyl alcohol) Raman spectroscopy Résumé : Poly(vinyl alcohol)- (PVA-) based activated carbon fibers (ACFs) with a high mesoporosity have been fabricated. The surface area and pore size distribution were fine-tuned by the careful control of the activation temperature and time. A mesopore volume fraction of 66% was obtained by activation at 1173 K for 120 min or 1273 K for 90 min. Raman spectroscopy revealed that more defect sites in the graphitic structure were found in samples with higher mesoporosity. Adsorption experiments demonstrated that the PVA-ACFs exhibited good adsorption capacities for both small-molecular-size iodine and the larger-size methylene blue, with adsorption capacities of up to 1934 and 709 mg/g, respectively. The adsorption kinetics of methylene blue on the PVA-ACFs was simulated by both a pseudo-second-order kinetic model and an intraparticle diffusion model. With an increase in mesoporosity, rate limitations on adsorption due to intraparticle diffusion were dramatically reduced. This resulted in an increase of up to a factor of 7 in the adsorption rate compared to that on microporous PVA-based ACFs. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8012852 Exemplaires
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Titre : Effect of organized assemblies, part VII: adsorption behavior of polyoxyethylated nonyl phenol at silica - cyclohexane interface and its efficiency in stabilizing the silica - cyclohexane dispersion Type de document : texte imprimé Auteurs : Pramila K. Misra, Auteur ; Uma Dash, Auteur ; Ponisseril Somasundaran, Auteur Année de publication : 2009 Article en page(s) : pp. 3403–3409 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Polyoxyethylated nonyl phenol Silica-cyclohexane interface Cyclohexane decreases Silica-water dispersion Oxyethylene units Résumé : The adsorption behavior of a series of nonionic polyoxyethylated nonyl phenol surfactants having same hydrocarbon chain length but varying oxyethylene chain has been studied spectrophotometrically at the silica−cyclohexane interface. The adsorption density is found to be independent of the number of oxyethylene units throughout the adsorption isotherms, except at higher surface coverage, where the adsorption density decreases with the increase in the number of oxyethylene units. The settling rate of the silica particles in cyclohexane decreases with the increase in adsorption density as well as oxyethylene chain length. On the other hand, the sediment volume decreases with the increase in the adsorption density, with a minimum for the surfactant having the least number of oxyethylene units. Surfactants with a longer oxyethylene chain partitions preferentially to the bulk solvent at higher concentrations, as a result of the change in the polarity of the medium. On the basis of adsorption density, settling rate, and sediment volume data, a model for the mechanism of stabilization of silica−cyclohexane dispersion has been proposed. The aromatic ring of the surfactant is assumed to be anchored on the silica surface through specific interaction with silanol hydrogen, while its nonyl and oxyethylene chains are suspended in the bulk cyclohexane solution. The protruding oxyethylene chain offers a strong steric resistance for particle−particle association leading to the stabilization of the silica−water dispersion. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801283f
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3403–3409[article] Effect of organized assemblies, part VII: adsorption behavior of polyoxyethylated nonyl phenol at silica - cyclohexane interface and its efficiency in stabilizing the silica - cyclohexane dispersion [texte imprimé] / Pramila K. Misra, Auteur ; Uma Dash, Auteur ; Ponisseril Somasundaran, Auteur . - 2009 . - pp. 3403–3409.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3403–3409
Mots-clés : Polyoxyethylated nonyl phenol Silica-cyclohexane interface Cyclohexane decreases Silica-water dispersion Oxyethylene units Résumé : The adsorption behavior of a series of nonionic polyoxyethylated nonyl phenol surfactants having same hydrocarbon chain length but varying oxyethylene chain has been studied spectrophotometrically at the silica−cyclohexane interface. The adsorption density is found to be independent of the number of oxyethylene units throughout the adsorption isotherms, except at higher surface coverage, where the adsorption density decreases with the increase in the number of oxyethylene units. The settling rate of the silica particles in cyclohexane decreases with the increase in adsorption density as well as oxyethylene chain length. On the other hand, the sediment volume decreases with the increase in the adsorption density, with a minimum for the surfactant having the least number of oxyethylene units. Surfactants with a longer oxyethylene chain partitions preferentially to the bulk solvent at higher concentrations, as a result of the change in the polarity of the medium. On the basis of adsorption density, settling rate, and sediment volume data, a model for the mechanism of stabilization of silica−cyclohexane dispersion has been proposed. The aromatic ring of the surfactant is assumed to be anchored on the silica surface through specific interaction with silanol hydrogen, while its nonyl and oxyethylene chains are suspended in the bulk cyclohexane solution. The protruding oxyethylene chain offers a strong steric resistance for particle−particle association leading to the stabilization of the silica−water dispersion. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801283f Exemplaires
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Titre : Tensile stress relaxation studies of TiO2 and nanosilica filled natural rubber composites Type de document : texte imprimé Auteurs : A. P. Meera, Auteur ; Sylvère Said, Auteur ; Yves Grohens, Auteur Année de publication : 2009 Article en page(s) : pp. 3410–3416 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Natural rubberTiO2 Nanosilice Silica-filled NR Kohlrausch equation Résumé : Composites of natural rubber were prepared with TiO2 and nanosilica. The stress relaxation behavior of the composites under tension was studied with reference to the filler loading and strain level. It was observed that the rate of stress relaxation increases with increase in filler loading. The rate of stress relaxation was found to be higher for silica-filled NR compared to TiO2-filled NR. This is due to the high degree of agglomeration in silica compared to titanium dioxide filler. The effect of ageing on the stress decay was also investigated and the rate of stress relaxation was found to decrease after ageing. The experimental curves were fitted with the stretched Kohlrausch equation. From the fitting parameters, the relaxation time and the stretching exponent were estimated in order to understand the mechanism of the relaxation processes in the filled natural rubber composites. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801494s
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3410–3416[article] Tensile stress relaxation studies of TiO2 and nanosilica filled natural rubber composites [texte imprimé] / A. P. Meera, Auteur ; Sylvère Said, Auteur ; Yves Grohens, Auteur . - 2009 . - pp. 3410–3416.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3410–3416
Mots-clés : Natural rubberTiO2 Nanosilice Silica-filled NR Kohlrausch equation Résumé : Composites of natural rubber were prepared with TiO2 and nanosilica. The stress relaxation behavior of the composites under tension was studied with reference to the filler loading and strain level. It was observed that the rate of stress relaxation increases with increase in filler loading. The rate of stress relaxation was found to be higher for silica-filled NR compared to TiO2-filled NR. This is due to the high degree of agglomeration in silica compared to titanium dioxide filler. The effect of ageing on the stress decay was also investigated and the rate of stress relaxation was found to decrease after ageing. The experimental curves were fitted with the stretched Kohlrausch equation. From the fitting parameters, the relaxation time and the stretching exponent were estimated in order to understand the mechanism of the relaxation processes in the filled natural rubber composites. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801494s Exemplaires
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Titre : Morphological and thermal-mechanical stretching properties on polymeric lateral flow nitrocellulose membrane Type de document : texte imprimé Auteurs : A. L. Ahmad, Auteur ; S. C. Low, Auteur ; S. R. Abd. Shukor, Auteur Année de publication : 2009 Article en page(s) : pp.3417–3424 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Flow nitrocellulose membrane Thermal-mechanical stretching technique Polymer Résumé : Lateral flow nitrocellulose (NC) membrane is well-known as the transport medium in a diagnostic test strip. The function of the membrane is greatly influenced by its physical morphology and chemical composition. Hence, a thermal-mechanical stretching technique was introduced to modify polymeric membrane morphologies for various performance studies. Membrane samples were stretched at the appropriate settings of stretching elongation, stretching speed, and stretching temperature. Experimental, AFM, and SEM results show that membrane morphologies changed significantly as a result of the stretching effects. The current study has demonstrated that physical thermal-mechanical stretching properties are important in modifying membrane morphologies for specific applications, since these parameters potentially affect the membrane’s final performances. These findings provided some insight on the relationship between stretched membranes’ morphology and performances. This knowledge is useful in producing both versatile and durable nitrocellulose membranes for lateral flow applications. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801282t
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp.3417–3424[article] Morphological and thermal-mechanical stretching properties on polymeric lateral flow nitrocellulose membrane [texte imprimé] / A. L. Ahmad, Auteur ; S. C. Low, Auteur ; S. R. Abd. Shukor, Auteur . - 2009 . - pp.3417–3424.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp.3417–3424
Mots-clés : Flow nitrocellulose membrane Thermal-mechanical stretching technique Polymer Résumé : Lateral flow nitrocellulose (NC) membrane is well-known as the transport medium in a diagnostic test strip. The function of the membrane is greatly influenced by its physical morphology and chemical composition. Hence, a thermal-mechanical stretching technique was introduced to modify polymeric membrane morphologies for various performance studies. Membrane samples were stretched at the appropriate settings of stretching elongation, stretching speed, and stretching temperature. Experimental, AFM, and SEM results show that membrane morphologies changed significantly as a result of the stretching effects. The current study has demonstrated that physical thermal-mechanical stretching properties are important in modifying membrane morphologies for specific applications, since these parameters potentially affect the membrane’s final performances. These findings provided some insight on the relationship between stretched membranes’ morphology and performances. This knowledge is useful in producing both versatile and durable nitrocellulose membranes for lateral flow applications. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801282t Exemplaires
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Titre : Adsorption and separation of noble gases by IRMOF-1 : grand canonical monte carlo simulations Type de document : texte imprimé Auteurs : Jeffery A. Greathouse, Auteur ; Tiffany L. Kinnibrugh, Auteur ; Mark D. Allendorf, Auteur Année de publication : 2009 Article en page(s) : pp. 3425–3431 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Metal-organic frameworks IRMOF-1 Grand canonical Monte Carlo simulations Xenon adsorption Résumé : The gas storage capacity of metal−organic frameworks (MOFs) is well-known and has been investigated using both experimental and computational methods. Previous Monte Carlo computer simulations of gas adsorption by MOFs have made several questionable approximations regarding framework−framework and framework−adsorbate interactions: potential parameters from general force fields have been used, and framework atoms were fixed at their crystallographic coordinates (rigid framework). We assess the validity of these approximations with grand canonical Monte Carlo simulations for a well-known Zn-based MOF (IRMOF-1), using potential parameters specifically derived for IRMOF-1. Our approach is validated by comparison with experimental results for hydrogen and xenon adsorption at room temperature. The effects of framework flexibility on the adsorption of noble gases and hydrogen are described, as well as the selectivity of IRMOF-1 for xenon versus other noble gases. At both low temperature (78 K) and room temperature, little difference in gas adsorption is seen between the rigid and flexible force fields. Experimental trends of noble gas inflation curves are also matched by the simulation results. Additionally, we show that IRMOF-1 selectively adsorbs Xe atoms in Xe/Kr and Xe/Ar mixtures, and this preference correlates with the trend in van der Waals parameters for the adsorbate atoms. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801294n
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3425–3431[article] Adsorption and separation of noble gases by IRMOF-1 : grand canonical monte carlo simulations [texte imprimé] / Jeffery A. Greathouse, Auteur ; Tiffany L. Kinnibrugh, Auteur ; Mark D. Allendorf, Auteur . - 2009 . - pp. 3425–3431.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3425–3431
Mots-clés : Metal-organic frameworks IRMOF-1 Grand canonical Monte Carlo simulations Xenon adsorption Résumé : The gas storage capacity of metal−organic frameworks (MOFs) is well-known and has been investigated using both experimental and computational methods. Previous Monte Carlo computer simulations of gas adsorption by MOFs have made several questionable approximations regarding framework−framework and framework−adsorbate interactions: potential parameters from general force fields have been used, and framework atoms were fixed at their crystallographic coordinates (rigid framework). We assess the validity of these approximations with grand canonical Monte Carlo simulations for a well-known Zn-based MOF (IRMOF-1), using potential parameters specifically derived for IRMOF-1. Our approach is validated by comparison with experimental results for hydrogen and xenon adsorption at room temperature. The effects of framework flexibility on the adsorption of noble gases and hydrogen are described, as well as the selectivity of IRMOF-1 for xenon versus other noble gases. At both low temperature (78 K) and room temperature, little difference in gas adsorption is seen between the rigid and flexible force fields. Experimental trends of noble gas inflation curves are also matched by the simulation results. Additionally, we show that IRMOF-1 selectively adsorbs Xe atoms in Xe/Kr and Xe/Ar mixtures, and this preference correlates with the trend in van der Waals parameters for the adsorbate atoms. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801294n Exemplaires
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Titre : Effect of a miscible polymeric diluent on complex formation between isotactic and syndiotactic poly(methyl methacrylate) Type de document : texte imprimé Auteurs : L. Chang, Auteur ; E. M. Woo, Auteur Année de publication : 2009 Article en page(s) : pp. 3432–3440 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Syndiotactic poly(methyl methacrylate)Thermal treatment Isotactic Miscible polymeric Résumé : Formation of a stereocomplex structure in a blend of isotactic and syndiotactic poly(methyl methacrylate)s (iPMMA/sPMMA) was found to be significantly enhanced by introducing a mutual miscible diluent of poly(ethylene oxide) (PEO) in the blend, even when prepared using a kinetically hindered noncomplexing CHCl3 solvent. Mechanisms and influencing factors, such as thermal treatment, annealing temperature, annealing time, or PEO content in blends, on structures of stereocomplexes in the ternary iPMMA/sPMMA/PEO blends are discussed. WAXD result showed that addition of PEO in the iPMMA/sPMMA blend did not alter the crystal cells in the complexes. Melting peaks associated with the complexes were analyzed for discerning possible structural mechanisms. When annealed at specific temperatures, multiple endothermic peaks of the complexes increased in intensity as PEO contents increased in the ternary blends. Analysis shows that the lower melting peak (P1) represents shorter stereocomplex sequences or stereocomplex detached from PEO or connected with partial PEO, but the higher melting peak (P3) is related to the stereocomplex physically interconnected in the presence of PEO. The PEO molecules are thought to more easily interact with the stereocomplexes in blends by acting as a plasticizer, which decreases Tg of the more rigid PMMA chain segments. Physical interaction or miscibility-enhanced chain entanglement probably exists between PEO and the stereocomplex of tactic PMMAs, leading to stereocomplex formation in the iPMMA/sPMMA/PEO ternary blend. FT-IR characterization provided evidence of weak interactions between PEO and the stereocomplex of PMMA. IR peaks sensitive to complex structures with respect to temperature were analyzed for discerning effects by adding PEO. The stereocomplex formation of ternary blends with PEO is due to the weak interaction of ester groups and methoxy groups between PMMA and PEO. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801488u
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3432–3440[article] Effect of a miscible polymeric diluent on complex formation between isotactic and syndiotactic poly(methyl methacrylate) [texte imprimé] / L. Chang, Auteur ; E. M. Woo, Auteur . - 2009 . - pp. 3432–3440.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3432–3440
Mots-clés : Syndiotactic poly(methyl methacrylate)Thermal treatment Isotactic Miscible polymeric Résumé : Formation of a stereocomplex structure in a blend of isotactic and syndiotactic poly(methyl methacrylate)s (iPMMA/sPMMA) was found to be significantly enhanced by introducing a mutual miscible diluent of poly(ethylene oxide) (PEO) in the blend, even when prepared using a kinetically hindered noncomplexing CHCl3 solvent. Mechanisms and influencing factors, such as thermal treatment, annealing temperature, annealing time, or PEO content in blends, on structures of stereocomplexes in the ternary iPMMA/sPMMA/PEO blends are discussed. WAXD result showed that addition of PEO in the iPMMA/sPMMA blend did not alter the crystal cells in the complexes. Melting peaks associated with the complexes were analyzed for discerning possible structural mechanisms. When annealed at specific temperatures, multiple endothermic peaks of the complexes increased in intensity as PEO contents increased in the ternary blends. Analysis shows that the lower melting peak (P1) represents shorter stereocomplex sequences or stereocomplex detached from PEO or connected with partial PEO, but the higher melting peak (P3) is related to the stereocomplex physically interconnected in the presence of PEO. The PEO molecules are thought to more easily interact with the stereocomplexes in blends by acting as a plasticizer, which decreases Tg of the more rigid PMMA chain segments. Physical interaction or miscibility-enhanced chain entanglement probably exists between PEO and the stereocomplex of tactic PMMAs, leading to stereocomplex formation in the iPMMA/sPMMA/PEO ternary blend. FT-IR characterization provided evidence of weak interactions between PEO and the stereocomplex of PMMA. IR peaks sensitive to complex structures with respect to temperature were analyzed for discerning effects by adding PEO. The stereocomplex formation of ternary blends with PEO is due to the weak interaction of ester groups and methoxy groups between PMMA and PEO. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801488u Exemplaires
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Titre : Preparation of magnetically separable mesoporous silica microspheres with open pore systems in supercritical carbon dioxide Type de document : texte imprimé Auteurs : Zhimin Chen, Auteur ; Mingchuan Zhuo, Auteur ; Fengfeng Xue, Auteur Année de publication : 2009 Article en page(s) : pp. 3441–3445 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Silica microspheres Magnetically separable mesoporous Carbon dioxide Résumé : Magnetically separable mesoporous silica microspheres with open pore systems have been synthesized in supercritical carbon dioxide (SC-CO2). In the experiments, using the excellent transport properties of supercritical carbon dioxide, an acetone solution containing iron(III) acetylacetonate [Fe(acac)3] was easily infiltrated into the mesopores of the microspheres. After thermal decomposition, the Fe(acac)3 was easily transformed into Fe3O4 nanoparticles. A comparison experiment verified that the carrying effect of Fe(acac)3 using SC-CO2 was better than that observed for the common method. The magnetic microspheres were characterized by transmission electron microscopy, energy-dispersive X-ray analysis (EDAX), powder X-ray diffraction, and nitrogen adsorption−desorption. The magnetically separable property of the microspheres was also tested. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801557y
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3441–3445[article] Preparation of magnetically separable mesoporous silica microspheres with open pore systems in supercritical carbon dioxide [texte imprimé] / Zhimin Chen, Auteur ; Mingchuan Zhuo, Auteur ; Fengfeng Xue, Auteur . - 2009 . - pp. 3441–3445.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3441–3445
Mots-clés : Silica microspheres Magnetically separable mesoporous Carbon dioxide Résumé : Magnetically separable mesoporous silica microspheres with open pore systems have been synthesized in supercritical carbon dioxide (SC-CO2). In the experiments, using the excellent transport properties of supercritical carbon dioxide, an acetone solution containing iron(III) acetylacetonate [Fe(acac)3] was easily infiltrated into the mesopores of the microspheres. After thermal decomposition, the Fe(acac)3 was easily transformed into Fe3O4 nanoparticles. A comparison experiment verified that the carrying effect of Fe(acac)3 using SC-CO2 was better than that observed for the common method. The magnetic microspheres were characterized by transmission electron microscopy, energy-dispersive X-ray analysis (EDAX), powder X-ray diffraction, and nitrogen adsorption−desorption. The magnetically separable property of the microspheres was also tested. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801557y Exemplaires
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Titre : Preparation and characterization of a robust and hydrophobic ceramic membrane via an improved surface grafting technique Type de document : texte imprimé Auteurs : Chiao Chien Wei, Auteur ; K. Li, Auteur Année de publication : 2009 Article en page(s) : pp. 3446–3452 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hydrophobic ceramic membranes Grafting method Roughness Résumé : Studies have shown that hydrophilic surfaces of ceramic membranes can be modified to be hydrophobic using a grafting method. In this study, a robust and hydrophobic ceramic hollow-fiber membrane was developed by introducing a pretreatment technique, followed by a grafting method. The contact angle of the grafted membranes using the pretreatment technique was approximately 140°, indicating that the hydrophilic membrane surfaces were successfully modified to be hydrophobic. The mean roughness and the root roughness of grafted membranes decreased from 41 to 27.6 nm and from 53.4 to 33.6 nm, respectively, indicating that the membrane was covered by a grafted layer. The mechanical strength of the membrane was retained after the grafting process, and the grafted membrane was found to be thermally stable up to 270 °C and chemically stable in hexane for 100 h. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801639d
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3446–3452[article] Preparation and characterization of a robust and hydrophobic ceramic membrane via an improved surface grafting technique [texte imprimé] / Chiao Chien Wei, Auteur ; K. Li, Auteur . - 2009 . - pp. 3446–3452.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3446–3452
Mots-clés : Hydrophobic ceramic membranes Grafting method Roughness Résumé : Studies have shown that hydrophilic surfaces of ceramic membranes can be modified to be hydrophobic using a grafting method. In this study, a robust and hydrophobic ceramic hollow-fiber membrane was developed by introducing a pretreatment technique, followed by a grafting method. The contact angle of the grafted membranes using the pretreatment technique was approximately 140°, indicating that the hydrophilic membrane surfaces were successfully modified to be hydrophobic. The mean roughness and the root roughness of grafted membranes decreased from 41 to 27.6 nm and from 53.4 to 33.6 nm, respectively, indicating that the membrane was covered by a grafted layer. The mechanical strength of the membrane was retained after the grafting process, and the grafted membrane was found to be thermally stable up to 270 °C and chemically stable in hexane for 100 h. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801639d Exemplaires
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Titre : Design of dynamic experiments in modeling for optimization of batch processes Type de document : texte imprimé Auteurs : Ernesto C. Martinez, Auteur ; Mariano D. Cristaldi, Auteur ; Ricardo J. Grau, Auteur Année de publication : 2009 Article en page(s) : pp. 3453–3465 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Designing dynamic experiments Hamilton− Jacobi− Bellman optimality equation Model-based policy iteration algorithm Résumé : Finding optimal operating conditions fast with a scarce budget of experimental runs is a key problem to speeding up the development of innovative products and processes. Modeling for optimization is proposed as a systematic approach to bias data gathering for iterative policy improvement through experimental design using first-principles models. Designing dynamic experiments that are optimally informative in order to reduce the uncertainty about the optimal operating conditions is addressed by integrating policy iteration based on the Hamilton−Jacobi−Bellman optimality equation with global sensitivity analysis. A conceptual framework for run-to-run convergence of a model-based policy iteration algorithm is proposed. Results obtained in the fed-batch fermentation of penicillin G are presented. The well-known Bajpai and Reuss bioreactor model validated with industrial data is used to increase on a run-to-run basis the amount of penicillin obtained by input policy optimization and selective (re)estimation of relevant model parameters. A remarkable improvement in productivity can be gain using a simple policy structure after only two modeling runs despite initial modeling uncertainty. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8000953
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3453–3465[article] Design of dynamic experiments in modeling for optimization of batch processes [texte imprimé] / Ernesto C. Martinez, Auteur ; Mariano D. Cristaldi, Auteur ; Ricardo J. Grau, Auteur . - 2009 . - pp. 3453–3465.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3453–3465
Mots-clés : Designing dynamic experiments Hamilton− Jacobi− Bellman optimality equation Model-based policy iteration algorithm Résumé : Finding optimal operating conditions fast with a scarce budget of experimental runs is a key problem to speeding up the development of innovative products and processes. Modeling for optimization is proposed as a systematic approach to bias data gathering for iterative policy improvement through experimental design using first-principles models. Designing dynamic experiments that are optimally informative in order to reduce the uncertainty about the optimal operating conditions is addressed by integrating policy iteration based on the Hamilton−Jacobi−Bellman optimality equation with global sensitivity analysis. A conceptual framework for run-to-run convergence of a model-based policy iteration algorithm is proposed. Results obtained in the fed-batch fermentation of penicillin G are presented. The well-known Bajpai and Reuss bioreactor model validated with industrial data is used to increase on a run-to-run basis the amount of penicillin obtained by input policy optimization and selective (re)estimation of relevant model parameters. A remarkable improvement in productivity can be gain using a simple policy structure after only two modeling runs despite initial modeling uncertainty. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8000953 Exemplaires
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Titre : Agglomeration detection by acoustic emission (AE) sensors in fluidized beds Type de document : texte imprimé Auteurs : Wang Jingdai, Auteur ; Yijia Cao, Auteur ; Xiaojing Jiang, Auteur Année de publication : 2009 Article en page(s) : pp. 3466–3473 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Fluidized beds Polyolefin Acoustic emission sensors Chaos analysis Résumé : The occurrence of agglomeration in fluidized-bed production of polyolefin can have negative impacts on the efficiency of the reactor operation and may lead to defluidization and unscheduled shutdown of the plant. A novel method by using acoustic emission (AE) sensors was developed to detect different types of agglomeration in fluidized bed. Chaos analysis was discussed, and coefficients of malfunction were defined to recognize agglomeration. AE signals we divided into micro-, meso-, and macroscales by wavelet transform, and on the basis of the energy of mesoscale fraction analysis of AE signals, a prediction model was developed to predict the size of moving chunks in the bed. The application effect of AE method was illustrated with experiments carried out both in laboratory and the plant. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800324m
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3466–3473[article] Agglomeration detection by acoustic emission (AE) sensors in fluidized beds [texte imprimé] / Wang Jingdai, Auteur ; Yijia Cao, Auteur ; Xiaojing Jiang, Auteur . - 2009 . - pp. 3466–3473.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3466–3473
Mots-clés : Fluidized beds Polyolefin Acoustic emission sensors Chaos analysis Résumé : The occurrence of agglomeration in fluidized-bed production of polyolefin can have negative impacts on the efficiency of the reactor operation and may lead to defluidization and unscheduled shutdown of the plant. A novel method by using acoustic emission (AE) sensors was developed to detect different types of agglomeration in fluidized bed. Chaos analysis was discussed, and coefficients of malfunction were defined to recognize agglomeration. AE signals we divided into micro-, meso-, and macroscales by wavelet transform, and on the basis of the energy of mesoscale fraction analysis of AE signals, a prediction model was developed to predict the size of moving chunks in the bed. The application effect of AE method was illustrated with experiments carried out both in laboratory and the plant. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800324m Exemplaires
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Titre : A new unified approach to valve stiction quantification and compensation Type de document : texte imprimé Auteurs : Lee Zhi Xiang Ivan, Auteur ; S. Lakshminarayanan, Auteur Année de publication : 2009 Article en page(s) : pp. 3474–3483 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Valve stiction Control loops Hammerstein identification approach Résumé : Satisfactory control loop performance has always been a vital objective in process industries for economic reasons. However, unsatisfactory performance may prevail, of which valve stiction is a common culprit. In this work, a new unified approach is introduced to quantify valve stiction in control loops and then compensate for it. The newly proposed stiction quantification method uses a one-parameter stiction model and is based on a modified Hammerstein identification approach. In conjunction with the stiction quantification algorithm, a novel compensation technique that adds a constant amplitude signal to the valve input signal is presented. The effectiveness of the proposed scheme is demonstrated using simulation examples. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800961f
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3474–3483[article] A new unified approach to valve stiction quantification and compensation [texte imprimé] / Lee Zhi Xiang Ivan, Auteur ; S. Lakshminarayanan, Auteur . - 2009 . - pp. 3474–3483.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3474–3483
Mots-clés : Valve stiction Control loops Hammerstein identification approach Résumé : Satisfactory control loop performance has always been a vital objective in process industries for economic reasons. However, unsatisfactory performance may prevail, of which valve stiction is a common culprit. In this work, a new unified approach is introduced to quantify valve stiction in control loops and then compensate for it. The newly proposed stiction quantification method uses a one-parameter stiction model and is based on a modified Hammerstein identification approach. In conjunction with the stiction quantification algorithm, a novel compensation technique that adds a constant amplitude signal to the valve input signal is presented. The effectiveness of the proposed scheme is demonstrated using simulation examples. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800961f Exemplaires
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Titre : Control of a column/pervaporation process for separating the ethanol/water zeotrope Type de document : texte imprimé Auteurs : William L. Luyben, Auteur Année de publication : 2009 Article en page(s) : pp. 3484–3495 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Pervaporation process Refrigeration Distillation columns Résumé : The pervaporation process features a liquid feed and retentate and a vapor permeate. The phase change produces a temperature decrease as the retentate flows through the unit. Since flux rates decrease with decreasing temperature, the conventional pervaporation unit consists of several membrane modules in series with interstage heating. The vapor permeate must be condensed for recovery and recycle, and refrigeration is usually required. Hybrid systems of distillation columns and pervaporation units are frequently used in situations where distillation alone is impossible or very expensive. Despite the many papers dealing with pervaporation, the issue of dynamic control seems to be almost completely unexplored. That is the purpose of this paper. A hybrid column/pervaporation process is studied that is designed to produce 99.77 wt % ethanol from a feed stream of ethanol/water mixture with composition near the azeotrope. The control objective is to maintain the purity of the ethanol product retentate stream in the face of disturbances in feed flowrate and feed composition. There are two possible manipulated variables: permeate pressure and retentate temperature. Permeate flux is increased by decreasing permeate pressure or increasing retentate temperature. A simplified dynamic pervaporation model is developed that captures the essential features of the process using energy and component balances along with overall pervaporation performance relationships. Dynamic simulations are used to demonstrate the effectiveness of a control structure that uses a cascade composition/temperature structure. A simple process modification is shown to improve controllability. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801428s
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3484–3495[article] Control of a column/pervaporation process for separating the ethanol/water zeotrope [texte imprimé] / William L. Luyben, Auteur . - 2009 . - pp. 3484–3495.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3484–3495
Mots-clés : Pervaporation process Refrigeration Distillation columns Résumé : The pervaporation process features a liquid feed and retentate and a vapor permeate. The phase change produces a temperature decrease as the retentate flows through the unit. Since flux rates decrease with decreasing temperature, the conventional pervaporation unit consists of several membrane modules in series with interstage heating. The vapor permeate must be condensed for recovery and recycle, and refrigeration is usually required. Hybrid systems of distillation columns and pervaporation units are frequently used in situations where distillation alone is impossible or very expensive. Despite the many papers dealing with pervaporation, the issue of dynamic control seems to be almost completely unexplored. That is the purpose of this paper. A hybrid column/pervaporation process is studied that is designed to produce 99.77 wt % ethanol from a feed stream of ethanol/water mixture with composition near the azeotrope. The control objective is to maintain the purity of the ethanol product retentate stream in the face of disturbances in feed flowrate and feed composition. There are two possible manipulated variables: permeate pressure and retentate temperature. Permeate flux is increased by decreasing permeate pressure or increasing retentate temperature. A simplified dynamic pervaporation model is developed that captures the essential features of the process using energy and component balances along with overall pervaporation performance relationships. Dynamic simulations are used to demonstrate the effectiveness of a control structure that uses a cascade composition/temperature structure. A simple process modification is shown to improve controllability. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801428s Exemplaires
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Titre : Development of a generalized mixed integer nonlinear programming model for assessing and improving the operational flexibility of water network designs Type de document : texte imprimé Auteurs : Chuei-Tin Chang, Auteur ; Bao-Hong Li, Auteur ; Chih-Wen Liou, Auteur Année de publication : 2009 Article en page(s) : pp. 3496–3504 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Water network Operational flexibility Mixed integer nonlinear program Résumé : In designing and operating any water network, a typical issue that must be addressed is concerned with the uncertain process conditions. A systematic procedure is proposed in this paper to enhance the operational flexibility of a given structure. Specifically, two design options have been investigated: (1) relaxation of the allowed maximum freshwater consumption rate in the nominal design and (2) installation of auxiliary pipelines and/or elimination of existing ones. The flexibility index model proposed by Swaney and Grossmann (1985) has been modified and formulated in a generalized format to evaluate the impact of introducing various modifications into an existing network. Since this model is a mixed integer nonlinear program (MINLP), it is in general very difficult to locate the global optima in the iterative solution processes. A simple and effective initialization procedure has also been devised in this work to facilitate successful convergence. The effectiveness of the proposed approach is demonstrated with two examples in this paper. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8015363
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3496–3504[article] Development of a generalized mixed integer nonlinear programming model for assessing and improving the operational flexibility of water network designs [texte imprimé] / Chuei-Tin Chang, Auteur ; Bao-Hong Li, Auteur ; Chih-Wen Liou, Auteur . - 2009 . - pp. 3496–3504.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3496–3504
Mots-clés : Water network Operational flexibility Mixed integer nonlinear program Résumé : In designing and operating any water network, a typical issue that must be addressed is concerned with the uncertain process conditions. A systematic procedure is proposed in this paper to enhance the operational flexibility of a given structure. Specifically, two design options have been investigated: (1) relaxation of the allowed maximum freshwater consumption rate in the nominal design and (2) installation of auxiliary pipelines and/or elimination of existing ones. The flexibility index model proposed by Swaney and Grossmann (1985) has been modified and formulated in a generalized format to evaluate the impact of introducing various modifications into an existing network. Since this model is a mixed integer nonlinear program (MINLP), it is in general very difficult to locate the global optima in the iterative solution processes. A simple and effective initialization procedure has also been devised in this work to facilitate successful convergence. The effectiveness of the proposed approach is demonstrated with two examples in this paper. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8015363 Exemplaires
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Titre : Chemical plant flare minimization via plantwide dynamic simulation Type de document : texte imprimé Auteurs : Qiang Xu, Auteur ; Xiongtao Yang, Auteur ; Chaowei Liu, Auteur Année de publication : 2009 Article en page(s) : pp. 3505–3512 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Flare minimization Plant start-up operations Plantwide dynamic simulation Résumé : Flaring is crucial to chemical plant safety. However, excessive flaring, especially the intensive flaring during the chemical plant start-up operation, emits huge amounts of volatile organic compounds (VOCs) and highly reactive VOCs, which meanwhile results in tremendous industrial material and energy loss. Thus, the flare emission should be minimized if at all possible. This paper presents a general methodology on flare minimization for chemical plant start-up operations via plantwide dynamic simulation. The methodology starts with setup and validation of plantwide steady-state and dynamic simulation models. The validated dynamic model is then systematically transformed to the initial state of start-up and thereafter virtually run to check the plant start-up procedures. Any infeasible or risky scenarios will be fed back to plant engineers for operation improvement. The plantwide dynamic simulation provides an insight into process dynamic behaviors, which is crucial for the plant to minimize the flaring while maintaining operational feasibility and safety. The efficacy of the developed methodology has been demonstrated by a real start-up test. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8016219
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3505–3512[article] Chemical plant flare minimization via plantwide dynamic simulation [texte imprimé] / Qiang Xu, Auteur ; Xiongtao Yang, Auteur ; Chaowei Liu, Auteur . - 2009 . - pp. 3505–3512.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3505–3512
Mots-clés : Flare minimization Plant start-up operations Plantwide dynamic simulation Résumé : Flaring is crucial to chemical plant safety. However, excessive flaring, especially the intensive flaring during the chemical plant start-up operation, emits huge amounts of volatile organic compounds (VOCs) and highly reactive VOCs, which meanwhile results in tremendous industrial material and energy loss. Thus, the flare emission should be minimized if at all possible. This paper presents a general methodology on flare minimization for chemical plant start-up operations via plantwide dynamic simulation. The methodology starts with setup and validation of plantwide steady-state and dynamic simulation models. The validated dynamic model is then systematically transformed to the initial state of start-up and thereafter virtually run to check the plant start-up procedures. Any infeasible or risky scenarios will be fed back to plant engineers for operation improvement. The plantwide dynamic simulation provides an insight into process dynamic behaviors, which is crucial for the plant to minimize the flaring while maintaining operational feasibility and safety. The efficacy of the developed methodology has been demonstrated by a real start-up test. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8016219 Exemplaires
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Titre : How to improve the model partitioning in a DSS for instrumentation design Type de document : texte imprimé Auteurs : Alejandro O. Domancich, Auteur ; Marcelo Durante, Auteur ; Sebastián Ferraro, Auteur Année de publication : 2009 Article en page(s) : pp. 3513–3525 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Decision Support System Direct method algorithm Résumé : In this Article, we present an extension to the observability analysis algorithm known as Direct Method (DM), which is an essential piece of a Decision Support System (DSS), whose purpose is to help engineers in the instrumentation design of industrial process plants. The main goal of this new version of DM algorithm is to improve the global performance of the DSS. The new variant, known as Extended Direct Method (EDM), incorporates a novel module that quantifies the degree of nonlinearity associated with the variables and equations of the mathematical model for the process plant. This new quantification procedure conforms a heuristic search, which guides the traditional DM toward a decomposition of the mathematical model in subsystems with the smallest possible degree of nonlinearity. The obtained results show that the EDM is able to reduce the nonlinearity of the subsystems obtained through the observability analysis procedure. At the same time, it can successfully increase the generated quantity of minimum size subsystems, thus also contributing to improve the DSS’s global performance. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800449t
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3513–3525[article] How to improve the model partitioning in a DSS for instrumentation design [texte imprimé] / Alejandro O. Domancich, Auteur ; Marcelo Durante, Auteur ; Sebastián Ferraro, Auteur . - 2009 . - pp. 3513–3525.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3513–3525
Mots-clés : Decision Support System Direct method algorithm Résumé : In this Article, we present an extension to the observability analysis algorithm known as Direct Method (DM), which is an essential piece of a Decision Support System (DSS), whose purpose is to help engineers in the instrumentation design of industrial process plants. The main goal of this new version of DM algorithm is to improve the global performance of the DSS. The new variant, known as Extended Direct Method (EDM), incorporates a novel module that quantifies the degree of nonlinearity associated with the variables and equations of the mathematical model for the process plant. This new quantification procedure conforms a heuristic search, which guides the traditional DM toward a decomposition of the mathematical model in subsystems with the smallest possible degree of nonlinearity. The obtained results show that the EDM is able to reduce the nonlinearity of the subsystems obtained through the observability analysis procedure. At the same time, it can successfully increase the generated quantity of minimum size subsystems, thus also contributing to improve the DSS’s global performance. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800449t Exemplaires
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Titre : Full-scale application of the alternating oxic/anoxic process : an overview Type de document : texte imprimé Auteurs : Paolo Nardelli, Auteur ; Giovanni Gatti, Auteur ; Anna Laura Eusebi, Auteur Année de publication : 2009 Article en page(s) : pp. 3526–3532 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Wastewater treatment plants Alternate cycle process Nitrogen loading rate approach Résumé : This article describes the results obtained in terms of nitrogen removal, energy savings, and waste sludge production upon application of an alternate cycle process and a remote control system in real wastewater treatment plants (WWTPs). The experimentation, which lasted for eight months, was performed in three extended oxidation plants (denoted WWTP1, WWTP2, and WWTP3) characterized by different structural designs and sewerage influent macropollutant concentrations. The alternate cycle (AC) process provided good total nitrogen biological removal. The results obtained were due to the excellent reduction of nitrates. In fact, comparison with the pre-AC period showed an average decrease of NO3-N of about 64% in WWTP1, 62% in WWTP2, and 33% in WWTP3. The behavior of all WWTPs can be rationalized according to a nitrogen loading rate (NLR) approach, showing that its increment determined a reduction of the length of the anoxic phase to allow for ammonia oxidation. All of these conditions assured the satisfaction of the limit on total nitrogen in effluent established in directive EC 91/271. The energy savings (13−26%) was always observed to be related to the time spent in the anoxic phase during which the blowers were switched off and the mixers were used for mixed liquor suspension and nitrates denitrification. Moreover, it was demonstrated, as a new aspect, that application of the AC process was able to reduce the waste activated sludge by a biomass stressing during the anoxic conditions. In addition, in WWTP3 where the influent mass loading and effluent suspended solid removal mainly were controlled, a consistent specific sludge reduction (up to 47%) was observed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8014796
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3526–3532[article] Full-scale application of the alternating oxic/anoxic process : an overview [texte imprimé] / Paolo Nardelli, Auteur ; Giovanni Gatti, Auteur ; Anna Laura Eusebi, Auteur . - 2009 . - pp. 3526–3532.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3526–3532
Mots-clés : Wastewater treatment plants Alternate cycle process Nitrogen loading rate approach Résumé : This article describes the results obtained in terms of nitrogen removal, energy savings, and waste sludge production upon application of an alternate cycle process and a remote control system in real wastewater treatment plants (WWTPs). The experimentation, which lasted for eight months, was performed in three extended oxidation plants (denoted WWTP1, WWTP2, and WWTP3) characterized by different structural designs and sewerage influent macropollutant concentrations. The alternate cycle (AC) process provided good total nitrogen biological removal. The results obtained were due to the excellent reduction of nitrates. In fact, comparison with the pre-AC period showed an average decrease of NO3-N of about 64% in WWTP1, 62% in WWTP2, and 33% in WWTP3. The behavior of all WWTPs can be rationalized according to a nitrogen loading rate (NLR) approach, showing that its increment determined a reduction of the length of the anoxic phase to allow for ammonia oxidation. All of these conditions assured the satisfaction of the limit on total nitrogen in effluent established in directive EC 91/271. The energy savings (13−26%) was always observed to be related to the time spent in the anoxic phase during which the blowers were switched off and the mixers were used for mixed liquor suspension and nitrates denitrification. Moreover, it was demonstrated, as a new aspect, that application of the AC process was able to reduce the waste activated sludge by a biomass stressing during the anoxic conditions. In addition, in WWTP3 where the influent mass loading and effluent suspended solid removal mainly were controlled, a consistent specific sludge reduction (up to 47%) was observed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8014796 Exemplaires
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Titre : Cointegration testing method for monitoring nonstationary processes Type de document : texte imprimé Auteurs : Qian Chen, Auteur ; Uwe Kruger, Auteur ; Andrew Y. T. Leung, Auteur Année de publication : 2009 Article en page(s) : pp. 3533–3543 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Cointegration testing method Nonstationary process Dynamic equilibrium Autocorrelated residual sequence Résumé : This paper introduces cointegration testing method for nonstationary process monitoring, which yields a long-run dynamic equilibrium relationship for nonstationary process systems. The process variables are examined, and then a cointegration model of the tested nonstationary variables is identified. The residual sequence of the cointegration model describes the dynamic equilibrium errors of the nonstationary process system and can be further analyzed for condition monitoring and fault detection purposes. The autocorrelated residual sequence is filtered with AR model first, then compensated to keep the fault signatures from being distorted by the filtering process. An application case study to an industrial distillation unit with a nonstatioanry process shows that a tidy cointegration model can describe the dynamic equilibruim state of the unit and correctly detect abnormal behavior of the process. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801611s
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3533–3543[article] Cointegration testing method for monitoring nonstationary processes [texte imprimé] / Qian Chen, Auteur ; Uwe Kruger, Auteur ; Andrew Y. T. Leung, Auteur . - 2009 . - pp. 3533–3543.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3533–3543
Mots-clés : Cointegration testing method Nonstationary process Dynamic equilibrium Autocorrelated residual sequence Résumé : This paper introduces cointegration testing method for nonstationary process monitoring, which yields a long-run dynamic equilibrium relationship for nonstationary process systems. The process variables are examined, and then a cointegration model of the tested nonstationary variables is identified. The residual sequence of the cointegration model describes the dynamic equilibrium errors of the nonstationary process system and can be further analyzed for condition monitoring and fault detection purposes. The autocorrelated residual sequence is filtered with AR model first, then compensated to keep the fault signatures from being distorted by the filtering process. An application case study to an industrial distillation unit with a nonstatioanry process shows that a tidy cointegration model can describe the dynamic equilibruim state of the unit and correctly detect abnormal behavior of the process. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801611s Exemplaires
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Titre : Thermodynamic insights on the feasibility of homogeneous batch extractive distillation, 1. Azeotropic mixtures with a heavy entrainer Type de document : texte imprimé Auteurs : Ivonne Rodriguez-Donis, Auteur ; Vincent Gerbaud, Auteur ; Xavier Joulia, Auteur Année de publication : 2009 Article en page(s) : pp. 3544–3559 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Batch extractive distillation Azeotropic mixture Heavy entrainer Résumé : Feasibility assessment of batch homogeneous extractive distillation for the separation of an A−B mixture feeding entrainer E traditionally relies on the systematic computation of rectifying and extractive composition profile maps under various reflux ratio and entrainer flow-rate conditions. This is a well-settled methodology for determining the product sequence and the corresponding column configuration. However, we show that all related literature examples can be simply explained using the thermodynamic insights of residue curve maps, in particular, the unidistribution and univolatility curves. A general feasibility criterion at infinite reflux is proposed and finite reflux operation is also discussed. Illustration is provided for the most common cases, namely, the separation with a heavy entrainer of minimum boiling (class 1.0-1a) and maximum boiling azeotropes (class 1.0-2). New cases that have not been published yet are presented, and operating conditions are also discussed. These results demonstrate the obligatory incorporation of the univolatility lines for explaining the unexpected behavior of some particular ternary mixtures to be separated by the homogeneous extractive distillation process. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801060n
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3544–3559[article] Thermodynamic insights on the feasibility of homogeneous batch extractive distillation, 1. Azeotropic mixtures with a heavy entrainer [texte imprimé] / Ivonne Rodriguez-Donis, Auteur ; Vincent Gerbaud, Auteur ; Xavier Joulia, Auteur . - 2009 . - pp. 3544–3559.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3544–3559
Mots-clés : Batch extractive distillation Azeotropic mixture Heavy entrainer Résumé : Feasibility assessment of batch homogeneous extractive distillation for the separation of an A−B mixture feeding entrainer E traditionally relies on the systematic computation of rectifying and extractive composition profile maps under various reflux ratio and entrainer flow-rate conditions. This is a well-settled methodology for determining the product sequence and the corresponding column configuration. However, we show that all related literature examples can be simply explained using the thermodynamic insights of residue curve maps, in particular, the unidistribution and univolatility curves. A general feasibility criterion at infinite reflux is proposed and finite reflux operation is also discussed. Illustration is provided for the most common cases, namely, the separation with a heavy entrainer of minimum boiling (class 1.0-1a) and maximum boiling azeotropes (class 1.0-2). New cases that have not been published yet are presented, and operating conditions are also discussed. These results demonstrate the obligatory incorporation of the univolatility lines for explaining the unexpected behavior of some particular ternary mixtures to be separated by the homogeneous extractive distillation process. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801060n Exemplaires
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Titre : Thermodynamic insights on the feasibility of homogeneous batch extractive distillation, 2. Low-relative-volatility binary mixtures with a heavy entrainer Type de document : texte imprimé Auteurs : Ivonne Rodriguez-Donis, Auteur ; Vincent Gerbaud, Auteur ; Xavier Joulia, Auteur Année de publication : 2009 Article en page(s) : pp. 3560–3572 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Low-relative-volatility binary mixture Heavy entrainer Azeotropic mixtures Batch rectifier Résumé : All former studies reported that the separation of the low-relative-volatility binary mixture using a heavy entrainer in a batch rectifier imposed the obligatory withdrawal of the most-volatile original component. In this paper, we demonstrate that this does not always happen, and that the product sequence can be unambiguously determined from the sole analysis of thermodynamic properties of residue curve maps and the occurrence of unidistribution lines and univolatility lines, following the general feasibility criterion enounced in the first part of this series of papers [Rodríguez-Donis et al., Ind. Eng. Chem. Res. 2009, 48, 3544-3559] for the separation of azeotropic mixtures using heavy or light entrainers. For low-relative-volatility mixtures, the original component that has an intermediate boiling temperature can be also drawn as the first distillate product. Cases concerning 94% of statistically occurring zeotropic ternary mixtures are investigated, which allows one to define the product sequence without any previous calculation of the liquid composition profile inside the column. Preliminary feasibility results are confirmed by computing maps of extractive and rectifying liquid composition profiles using a simplified mass balance. Final validation is done via rigorous simulation using ProSim Batch software. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801061y
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3560–3572[article] Thermodynamic insights on the feasibility of homogeneous batch extractive distillation, 2. Low-relative-volatility binary mixtures with a heavy entrainer [texte imprimé] / Ivonne Rodriguez-Donis, Auteur ; Vincent Gerbaud, Auteur ; Xavier Joulia, Auteur . - 2009 . - pp. 3560–3572.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3560–3572
Mots-clés : Low-relative-volatility binary mixture Heavy entrainer Azeotropic mixtures Batch rectifier Résumé : All former studies reported that the separation of the low-relative-volatility binary mixture using a heavy entrainer in a batch rectifier imposed the obligatory withdrawal of the most-volatile original component. In this paper, we demonstrate that this does not always happen, and that the product sequence can be unambiguously determined from the sole analysis of thermodynamic properties of residue curve maps and the occurrence of unidistribution lines and univolatility lines, following the general feasibility criterion enounced in the first part of this series of papers [Rodríguez-Donis et al., Ind. Eng. Chem. Res. 2009, 48, 3544-3559] for the separation of azeotropic mixtures using heavy or light entrainers. For low-relative-volatility mixtures, the original component that has an intermediate boiling temperature can be also drawn as the first distillate product. Cases concerning 94% of statistically occurring zeotropic ternary mixtures are investigated, which allows one to define the product sequence without any previous calculation of the liquid composition profile inside the column. Preliminary feasibility results are confirmed by computing maps of extractive and rectifying liquid composition profiles using a simplified mass balance. Final validation is done via rigorous simulation using ProSim Batch software. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801061y Exemplaires
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Titre : Hydrometallurgical recovery of germanium from coal gasification fly ash : pilot plant scale evaluation Type de document : texte imprimé Auteurs : Fátima Arroyo, Auteur ; Constantino Fernández-Pereira, Auteur ; Joaquín Olivares, Auteur Année de publication : 2009 Article en page(s) : pp. 3573–3579 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Germanium Fly ash Hydrometallurgical method Solvent extraction Résumé : In this article, a hydrometallurgical method for the selective recovery of germanium from fly ash (FA) has been tested at pilot plant scale. The pilot plant flowsheet comprised a first stage of water leaching of FA, and a subsequent selective recovery of the germanium from the leachate by solvent extraction method. The solvent extraction method was based on Ge complexation with catechol in an aqueous solution followed by the extraction of the Ge−catechol complex (Ge(C6H4O2)32−) with an extracting organic reagent (trioctylamine) diluted in an organic solvent (kerosene), the relevant reaction probably being 2(C8H17)3N(org) + Ge(OH)4o(aq) + 3(C6H6O2)(aq) ↔ ((C8H17)3NH)2Ge(C6H4O2)3(org) + 4H2O(aq) followed by the subsequent stripping of the organic extract. The process has been tested on a FA generated in an integrated gasification with combined cycle (IGCC) process. The paper describes the designed 5 kg/h pilot plant and the tests performed on it. Under the operational conditions tested, approximately 50% of germanium could be recovered from FA after a water extraction at room temperature. Regarding the solvent extraction method, the best operational conditions for obtaining a concentrated germanium-bearing solution practically free of impurities were as follows: extraction time equal to 20 min; aqueous phase/organic phase volumetric ratio equal to 5; stripping with 1 M NaOH, stripping time equal to 30 min, and stripping phase/organic phase volumetric ratio equal to 5. 95% of germanium were recovered from water leachates using those conditions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800730h
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3573–3579[article] Hydrometallurgical recovery of germanium from coal gasification fly ash : pilot plant scale evaluation [texte imprimé] / Fátima Arroyo, Auteur ; Constantino Fernández-Pereira, Auteur ; Joaquín Olivares, Auteur . - 2009 . - pp. 3573–3579.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3573–3579
Mots-clés : Germanium Fly ash Hydrometallurgical method Solvent extraction Résumé : In this article, a hydrometallurgical method for the selective recovery of germanium from fly ash (FA) has been tested at pilot plant scale. The pilot plant flowsheet comprised a first stage of water leaching of FA, and a subsequent selective recovery of the germanium from the leachate by solvent extraction method. The solvent extraction method was based on Ge complexation with catechol in an aqueous solution followed by the extraction of the Ge−catechol complex (Ge(C6H4O2)32−) with an extracting organic reagent (trioctylamine) diluted in an organic solvent (kerosene), the relevant reaction probably being 2(C8H17)3N(org) + Ge(OH)4o(aq) + 3(C6H6O2)(aq) ↔ ((C8H17)3NH)2Ge(C6H4O2)3(org) + 4H2O(aq) followed by the subsequent stripping of the organic extract. The process has been tested on a FA generated in an integrated gasification with combined cycle (IGCC) process. The paper describes the designed 5 kg/h pilot plant and the tests performed on it. Under the operational conditions tested, approximately 50% of germanium could be recovered from FA after a water extraction at room temperature. Regarding the solvent extraction method, the best operational conditions for obtaining a concentrated germanium-bearing solution practically free of impurities were as follows: extraction time equal to 20 min; aqueous phase/organic phase volumetric ratio equal to 5; stripping with 1 M NaOH, stripping time equal to 30 min, and stripping phase/organic phase volumetric ratio equal to 5. 95% of germanium were recovered from water leachates using those conditions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800730h Exemplaires
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Titre : Effects of mass transfer on the steady state and dynamic performance of a Kühni column : experimental observations Type de document : texte imprimé Auteurs : Luísa N. Gomes, Auteur ; Margarida L. Guimarães, Auteur ; Johann Stichlmair, Auteur Année de publication : 2009 Article en page(s) : pp. 3580–3588 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Kühni column Mass transfer Steady state Dynamic behavior Résumé : Experimental data obtained in a pilot-scale Kühni liquid−liquid extraction column were used to obtain local drop size distributions, dispersed-phase hold-up profiles, and solute concentrations. To obtain information about the dynamic behavior of the column, several experiments were planned and performed, under both steady and controlled transient conditions, with and without mass transfer. The analysis of the effects of the presence of a transferring solute (not of the mass transfer flux itself) on the dispersion’s steady state and dynamic behavior was the main objective. For this, we imposed forced step variations in the operating conditions − agitation intensity and continuous and dispersed-phase flowrates. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801034a
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3580–3588[article] Effects of mass transfer on the steady state and dynamic performance of a Kühni column : experimental observations [texte imprimé] / Luísa N. Gomes, Auteur ; Margarida L. Guimarães, Auteur ; Johann Stichlmair, Auteur . - 2009 . - pp. 3580–3588.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3580–3588
Mots-clés : Kühni column Mass transfer Steady state Dynamic behavior Résumé : Experimental data obtained in a pilot-scale Kühni liquid−liquid extraction column were used to obtain local drop size distributions, dispersed-phase hold-up profiles, and solute concentrations. To obtain information about the dynamic behavior of the column, several experiments were planned and performed, under both steady and controlled transient conditions, with and without mass transfer. The analysis of the effects of the presence of a transferring solute (not of the mass transfer flux itself) on the dispersion’s steady state and dynamic behavior was the main objective. For this, we imposed forced step variations in the operating conditions − agitation intensity and continuous and dispersed-phase flowrates. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801034a Exemplaires
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Titre : Biosorption of As(V) onto the shells of the crab (portunus sanguinolentus) : equilibrium and kinetic studies Type de document : texte imprimé Auteurs : K. Vijayaraghavan, Auteur ; Mahadevan Arun, Auteur ; Umid Man Joshi, Auteur Année de publication : 2009 Article en page(s) : pp. 3589–3594 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Crab shells Arsenic(V) Aqueous solution Systematic equilibrium Kinetic studies Résumé : Worldwide concerns over inorganic arsenic in water bodies have prompted much research and policy development focusing on removal of this chronic human carcinogen. In the present study, the potential use of shell particles of crab (Portunus sanguinolentus) for removal of arsenic(V) from aqueous solution was investigated on the basis of systematic equilibrium and kinetic studies. Crab shells favor the removal of arsenate ion, especially under acidic pH conditions, because of the presence of CaCO3 and chitin in the biosorbent. The scanning electron micrographs together with energy dispersive X-ray analysis (EDX) confirmed the presence of arsenic on the crab shells. A series of isotherm experiments conducted at different pH conditions revealed that pH 3 favored arsenic biosorption. Among the four isotherm models (Langmuir, Freundlich, Redlich−Peterson, and Toth) employed in the study, the Toth model provided a better fit with the experimental data than others as revealed by high correlation coefficients, low % error, and root-mean-square error (rmse) values. The arsenic biosorption kinetics was very fast, and the kinetics data were successfully modeled using nonlinear pseudo-second-order model. As the ionic strength increased, arsenic uptake declined to a great extent. Desorption experiments were conducted to explore the feasibility of regenerating the biosorbent for further use. Results indicated that 0.1 M NaOH was sufficiently strong to remove the biosorbed arsenate ions from the crab shell with elution efficiency of 98.2%. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801570v
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3589–3594[article] Biosorption of As(V) onto the shells of the crab (portunus sanguinolentus) : equilibrium and kinetic studies [texte imprimé] / K. Vijayaraghavan, Auteur ; Mahadevan Arun, Auteur ; Umid Man Joshi, Auteur . - 2009 . - pp. 3589–3594.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3589–3594
Mots-clés : Crab shells Arsenic(V) Aqueous solution Systematic equilibrium Kinetic studies Résumé : Worldwide concerns over inorganic arsenic in water bodies have prompted much research and policy development focusing on removal of this chronic human carcinogen. In the present study, the potential use of shell particles of crab (Portunus sanguinolentus) for removal of arsenic(V) from aqueous solution was investigated on the basis of systematic equilibrium and kinetic studies. Crab shells favor the removal of arsenate ion, especially under acidic pH conditions, because of the presence of CaCO3 and chitin in the biosorbent. The scanning electron micrographs together with energy dispersive X-ray analysis (EDX) confirmed the presence of arsenic on the crab shells. A series of isotherm experiments conducted at different pH conditions revealed that pH 3 favored arsenic biosorption. Among the four isotherm models (Langmuir, Freundlich, Redlich−Peterson, and Toth) employed in the study, the Toth model provided a better fit with the experimental data than others as revealed by high correlation coefficients, low % error, and root-mean-square error (rmse) values. The arsenic biosorption kinetics was very fast, and the kinetics data were successfully modeled using nonlinear pseudo-second-order model. As the ionic strength increased, arsenic uptake declined to a great extent. Desorption experiments were conducted to explore the feasibility of regenerating the biosorbent for further use. Results indicated that 0.1 M NaOH was sufficiently strong to remove the biosorbed arsenate ions from the crab shell with elution efficiency of 98.2%. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801570v Exemplaires
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Titre : Separation of succinic acid from fermentation broth using weak alkaline anion exchange adsorbents Type de document : texte imprimé Auteurs : Qiang Li, Auteur ; Jianmin Xing, Auteur ; Wangliang Li, Auteur Année de publication : 2009 Article en page(s) : pp. 3595–3599 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Succinic acid Separation Adsorption Weak alkaline anion exchange adsorbe Langmuir/Freundlich isotherm models Pseudo-first/second-order equations Résumé : Succinic acid is one of the platform chemicals that can be bioproduced from renewable resources. Separation of succinic acid by adsorption from model solutions and fermentation broth by weak alkaline anion exchange adsorbents was studied. Adsorption capacities and regenerability of several sorts of adsorbents were tested. In a static test, the adsorbent NERCB 09 has the adsorption capacity of 0.11 g succinic acid g−1 at succinic acid concentrations of 5 g L−1. In packed column test, its capacity was as high as 0.56 g succinic acid g−1 when the feeding concentration was 50 g L−1. NERCB 09 showed the high selectivity toward succinate over both glucose and amino acid at acidic or neutral conditions. Langmuir/Freundlich isotherm models and pseudo-first/second-order equations were presented to simulate the adsorption behavior. Data showed that the temperature had little effect on the adsorption isotherm. Kinetic parameters suggested that about 1.5 h were sufficient for the adsorption equilibrium. The adsorbent was easily regenerated. The adsorption capacity was steady after 30 cycles and showed 96% average recovery. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801304k
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3595–3599[article] Separation of succinic acid from fermentation broth using weak alkaline anion exchange adsorbents [texte imprimé] / Qiang Li, Auteur ; Jianmin Xing, Auteur ; Wangliang Li, Auteur . - 2009 . - pp. 3595–3599.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3595–3599
Mots-clés : Succinic acid Separation Adsorption Weak alkaline anion exchange adsorbe Langmuir/Freundlich isotherm models Pseudo-first/second-order equations Résumé : Succinic acid is one of the platform chemicals that can be bioproduced from renewable resources. Separation of succinic acid by adsorption from model solutions and fermentation broth by weak alkaline anion exchange adsorbents was studied. Adsorption capacities and regenerability of several sorts of adsorbents were tested. In a static test, the adsorbent NERCB 09 has the adsorption capacity of 0.11 g succinic acid g−1 at succinic acid concentrations of 5 g L−1. In packed column test, its capacity was as high as 0.56 g succinic acid g−1 when the feeding concentration was 50 g L−1. NERCB 09 showed the high selectivity toward succinate over both glucose and amino acid at acidic or neutral conditions. Langmuir/Freundlich isotherm models and pseudo-first/second-order equations were presented to simulate the adsorption behavior. Data showed that the temperature had little effect on the adsorption isotherm. Kinetic parameters suggested that about 1.5 h were sufficient for the adsorption equilibrium. The adsorbent was easily regenerated. The adsorption capacity was steady after 30 cycles and showed 96% average recovery. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801304k Exemplaires
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Titre : CO2 removal from CO2-CH4 gas mixture using different solvents and hollow fiber membranes Type de document : texte imprimé Auteurs : Mohamed H. Al-Marzouqi, Auteur ; Sayed A. M. Marzouk, Auteur ; Muftah H. El-Naas, Auteur Année de publication : 2009 Article en page(s) : pp. 3600–3605 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hollow fiber membrane CO2 removal CO2-CH4 gas mixture Liquid flow rate Résumé : Commercial hollow fiber membrane modules have been investigated for the selective removal of CO2 from the CO2−CH4 gas mixture. Experiments were carried out to evaluate the effectiveness of different membrane modules and different solvents for the removal of CO2 from a gas mixture containing 10% CO2 and 90% CH4. Three different membrane modules with fibers made from polypropylene, super phobic polypropylene, and silicone rubber were used in this study. The effects of gas and liquid flow rates, temperature, solvent type and concentration, and membrane module type were investigated. The experimental results indicated that CO2 removal increased with increasing the liquid flow rate, decreasing gas flow rate, and increasing solvent concentration. For physical absorption, the CO2 removal decreased with increasing temperature, whereas temperature had negligible effect using chemical absorption. The polypropylene module showed the best performance in terms of CO2 flux. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800977z
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3600–3605[article] CO2 removal from CO2-CH4 gas mixture using different solvents and hollow fiber membranes [texte imprimé] / Mohamed H. Al-Marzouqi, Auteur ; Sayed A. M. Marzouk, Auteur ; Muftah H. El-Naas, Auteur . - 2009 . - pp. 3600–3605.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3600–3605
Mots-clés : Hollow fiber membrane CO2 removal CO2-CH4 gas mixture Liquid flow rate Résumé : Commercial hollow fiber membrane modules have been investigated for the selective removal of CO2 from the CO2−CH4 gas mixture. Experiments were carried out to evaluate the effectiveness of different membrane modules and different solvents for the removal of CO2 from a gas mixture containing 10% CO2 and 90% CH4. Three different membrane modules with fibers made from polypropylene, super phobic polypropylene, and silicone rubber were used in this study. The effects of gas and liquid flow rates, temperature, solvent type and concentration, and membrane module type were investigated. The experimental results indicated that CO2 removal increased with increasing the liquid flow rate, decreasing gas flow rate, and increasing solvent concentration. For physical absorption, the CO2 removal decreased with increasing temperature, whereas temperature had negligible effect using chemical absorption. The polypropylene module showed the best performance in terms of CO2 flux. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800977z Exemplaires
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Titre : Flow field visualization in structured packing using real time X-ray radiography Type de document : texte imprimé Auteurs : Scott A. Owens, Auteur ; Andreas Kossmann, Auteur ; John Farone, Auteur Année de publication : 2009 Article en page(s) : pp. 3606–3618 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Computational fluid dynamics X-ray radiography Vapor flow Structured packing Résumé : This research developed an experimental method for validating the CFD representation of single-phase (vapor) flow through structured packing. Real time X-ray radiography was used to visualize fluid streamlines in structured packing by tracking neutrally buoyant X-ray absorbing particles entrained in water flow. Flow through the packing was found to be uniform, whereas flow at the packing element joints exhibited chaotic flow and recirculation zones. Individual radiographs were analyzed to determine particle displacement and compute local velocities. This data could be used to validate existing computational fluid dynamics (CFD) models, including fluids other than water through the use of similarity theory. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801260s
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3606–3618[article] Flow field visualization in structured packing using real time X-ray radiography [texte imprimé] / Scott A. Owens, Auteur ; Andreas Kossmann, Auteur ; John Farone, Auteur . - 2009 . - pp. 3606–3618.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3606–3618
Mots-clés : Computational fluid dynamics X-ray radiography Vapor flow Structured packing Résumé : This research developed an experimental method for validating the CFD representation of single-phase (vapor) flow through structured packing. Real time X-ray radiography was used to visualize fluid streamlines in structured packing by tracking neutrally buoyant X-ray absorbing particles entrained in water flow. Flow through the packing was found to be uniform, whereas flow at the packing element joints exhibited chaotic flow and recirculation zones. Individual radiographs were analyzed to determine particle displacement and compute local velocities. This data could be used to validate existing computational fluid dynamics (CFD) models, including fluids other than water through the use of similarity theory. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801260s Exemplaires
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Titre : Treatment of cyanide bearing water/wastewater by plain and biological activated carbon Type de document : texte imprimé Auteurs : Rajesh Roshan Dash, Auteur ; Chandrajit Balomajumder, Auteur ; Arvind Kumar, Auteur Année de publication : 2009 Article en page(s) : pp. 3619–3627 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Cyanide SAB process Granular activated carbon Adsorption Biodegradation Résumé : Comparative study of biodegradation and adsorption alone with simultaneous adsorption and biodegradation (SAB) process was carried out along with a brief review of the processes. Adsorption and SAB studies were carried out in plain and Pseudomonas putida immobilized granular activated carbon (GAC), whereas biodegradation was conducted with suspended cultures of P. putida. P. putida used iron cyanide as the sole source of nitrogen at an initial pH of 7.0 and temperature of 30 °C. At an initial iron(II) cyanide concentration of 100 mg/L, removal efficiencies of cyanide by adsorption, biodegradation, and SAB were found to be 81.5%, 78.2%, and 96.7%, respectively. The initial ferrocyanide concentrations of 50−350 mg CN−/L were taken for the study. The microbes adopted to grow at maximum cyanide concentration were harvested, and their ability to degrade cyanide were measured in both biodegradation and SAB. The removal efficiency of biologically activated granular activated carbon (BAC) was found better as compared to that of plain GAC. It was also found that the SAB process is more effective than adsorption and biodegradation alone. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071299y
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3619–3627[article] Treatment of cyanide bearing water/wastewater by plain and biological activated carbon [texte imprimé] / Rajesh Roshan Dash, Auteur ; Chandrajit Balomajumder, Auteur ; Arvind Kumar, Auteur . - 2009 . - pp. 3619–3627.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3619–3627
Mots-clés : Cyanide SAB process Granular activated carbon Adsorption Biodegradation Résumé : Comparative study of biodegradation and adsorption alone with simultaneous adsorption and biodegradation (SAB) process was carried out along with a brief review of the processes. Adsorption and SAB studies were carried out in plain and Pseudomonas putida immobilized granular activated carbon (GAC), whereas biodegradation was conducted with suspended cultures of P. putida. P. putida used iron cyanide as the sole source of nitrogen at an initial pH of 7.0 and temperature of 30 °C. At an initial iron(II) cyanide concentration of 100 mg/L, removal efficiencies of cyanide by adsorption, biodegradation, and SAB were found to be 81.5%, 78.2%, and 96.7%, respectively. The initial ferrocyanide concentrations of 50−350 mg CN−/L were taken for the study. The microbes adopted to grow at maximum cyanide concentration were harvested, and their ability to degrade cyanide were measured in both biodegradation and SAB. The removal efficiency of biologically activated granular activated carbon (BAC) was found better as compared to that of plain GAC. It was also found that the SAB process is more effective than adsorption and biodegradation alone. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071299y Exemplaires
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Titre : Modeling the multiphase flow in a dense medium cyclone Type de document : texte imprimé Auteurs : B. Wang, Auteur ; K. W. Chu, Auteur ; A. B. Yu, Auteur Année de publication : 2009 Article en page(s) : pp. 3628–3639 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Multiphase flow Dense-medium cyclone Fluid multiphase model Reynolds stress Résumé : A mathematical model is proposed to describe the multiphase flow in a dense-medium cyclone (DMC). In this model, the volume of fluid multiphase model is first used to determine the shape and position of the air core, and then the mixture multiphase model is employed to describe the flow of the dense medium (comprising finely ground magnetite in water) and the air core, where the turbulence is described by the Reynolds stress model. The results of fluid flow are finally used in the simulation of coal particle flow described by the stochastic Lagrangian particle tracking model. The validity of the proposed approach is verified by the reasonably good agreement between the measured and predicted results under different conditions. The flow features in a DMC are then examined in terms of factors such as flow field, pressure drop, particle trajectories, and separation efficiency. The results are used to explain the key characteristics of flow in DMCs, such as the origin of a short-circuit flow, the flow pattern, and the motion of coal particles. Moreover, the so-called surging phenomenon is examined in relation to the instability of fluid flow. The model offers a convenient method to investigate the effects of variables related to geometrical and operational conditions on the performance of DMCs. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801175c
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3628–3639[article] Modeling the multiphase flow in a dense medium cyclone [texte imprimé] / B. Wang, Auteur ; K. W. Chu, Auteur ; A. B. Yu, Auteur . - 2009 . - pp. 3628–3639.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3628–3639
Mots-clés : Multiphase flow Dense-medium cyclone Fluid multiphase model Reynolds stress Résumé : A mathematical model is proposed to describe the multiphase flow in a dense-medium cyclone (DMC). In this model, the volume of fluid multiphase model is first used to determine the shape and position of the air core, and then the mixture multiphase model is employed to describe the flow of the dense medium (comprising finely ground magnetite in water) and the air core, where the turbulence is described by the Reynolds stress model. The results of fluid flow are finally used in the simulation of coal particle flow described by the stochastic Lagrangian particle tracking model. The validity of the proposed approach is verified by the reasonably good agreement between the measured and predicted results under different conditions. The flow features in a DMC are then examined in terms of factors such as flow field, pressure drop, particle trajectories, and separation efficiency. The results are used to explain the key characteristics of flow in DMCs, such as the origin of a short-circuit flow, the flow pattern, and the motion of coal particles. Moreover, the so-called surging phenomenon is examined in relation to the instability of fluid flow. The model offers a convenient method to investigate the effects of variables related to geometrical and operational conditions on the performance of DMCs. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801175c Exemplaires
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Titre : Expanded fluid-based viscosity correlation for hydrocarbons Type de document : texte imprimé Auteurs : Harvey W. Yarranton, Auteur ; M. A. Satyro, Auteur Année de publication : 2009 Article en page(s) : pp. 3640–3648 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hydrocarbons Viscosity Correlation Résumé : The viscosity of pure hydrocarbons was correlated using a simple function based on the fluid density. The correlation has three adjustable parameters, a compressed state density, ρs°, an empirical parameter, c2, that scales the viscosity response to fluid expansion, and another empirical parameter, c3, used to tune at pressures above 10 MPa. The inputs to the correlation are the fluid density, pressure, and low-pressure gas viscosity. The correlation fit experimental viscosities for 39 pure hydrocarbons including n-alkanes, branched alkanes, alkenes, cyclics, and aromatics, within experimental error over a broad range of temperatures and pressures. Heavy hydrocarbons such as mineral oils were also fit with an AAPRD of 2.7%. Binary mixture viscosities were predicted to within 10% using simple volumetric mixing rules. The method provides a single framework for liquid and vapor phases, is simple to implement, and is very fast computationally, making it ideal for incorporation into process and reservoir simulators. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801698h
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3640–3648[article] Expanded fluid-based viscosity correlation for hydrocarbons [texte imprimé] / Harvey W. Yarranton, Auteur ; M. A. Satyro, Auteur . - 2009 . - pp. 3640–3648.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3640–3648
Mots-clés : Hydrocarbons Viscosity Correlation Résumé : The viscosity of pure hydrocarbons was correlated using a simple function based on the fluid density. The correlation has three adjustable parameters, a compressed state density, ρs°, an empirical parameter, c2, that scales the viscosity response to fluid expansion, and another empirical parameter, c3, used to tune at pressures above 10 MPa. The inputs to the correlation are the fluid density, pressure, and low-pressure gas viscosity. The correlation fit experimental viscosities for 39 pure hydrocarbons including n-alkanes, branched alkanes, alkenes, cyclics, and aromatics, within experimental error over a broad range of temperatures and pressures. Heavy hydrocarbons such as mineral oils were also fit with an AAPRD of 2.7%. Binary mixture viscosities were predicted to within 10% using simple volumetric mixing rules. The method provides a single framework for liquid and vapor phases, is simple to implement, and is very fast computationally, making it ideal for incorporation into process and reservoir simulators. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801698h Exemplaires
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Titre : Analysis of oxygen-condensate interactions in metal powder production : sprayed particles in a carrier gas phase Type de document : texte imprimé Auteurs : Elisabetta Arato, Auteur ; Enrica Ricci, Auteur ; Paolo Costa, Auteur Année de publication : 2009 Article en page(s) : pp. 3649–3656 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ssprayed metal-carrier gas system Droplet surface Liquid steady state Phase equilibrium Interfacial Résumé : A preliminary, theoretical, analysis of the interfacial oxidization phenomena in a sprayed metal−carrier gas system was made to determine the initial conditions of the process which are compatible or not with surface saturation and the appearance of a separate oxide phase on the droplet surface. This discussion is based on previous theoretical and experimental works on single drop behavior. For the purpose of the discussion the liquid steady state, phase equilibrium and interfacial equilibrium conditions have been discussed; the material balance links of the phases and their coupling with the equilibrium equation have been examined; and the importance of the time variable and the various characteristic times has been underlined. Finally, by coupling the interface steady state conditions and oxygen material balance a set of sufficient conditions for obtaining a clean pure metallic phase has been derived. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800402h
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3649–3656[article] Analysis of oxygen-condensate interactions in metal powder production : sprayed particles in a carrier gas phase [texte imprimé] / Elisabetta Arato, Auteur ; Enrica Ricci, Auteur ; Paolo Costa, Auteur . - 2009 . - pp. 3649–3656.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3649–3656
Mots-clés : Ssprayed metal-carrier gas system Droplet surface Liquid steady state Phase equilibrium Interfacial Résumé : A preliminary, theoretical, analysis of the interfacial oxidization phenomena in a sprayed metal−carrier gas system was made to determine the initial conditions of the process which are compatible or not with surface saturation and the appearance of a separate oxide phase on the droplet surface. This discussion is based on previous theoretical and experimental works on single drop behavior. For the purpose of the discussion the liquid steady state, phase equilibrium and interfacial equilibrium conditions have been discussed; the material balance links of the phases and their coupling with the equilibrium equation have been examined; and the importance of the time variable and the various characteristic times has been underlined. Finally, by coupling the interface steady state conditions and oxygen material balance a set of sufficient conditions for obtaining a clean pure metallic phase has been derived. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800402h Exemplaires
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Titre : Spray drying of suspensions for pharma and bio products : drying kinetics and morphology Type de document : texte imprimé Auteurs : Jakob Sloth, Auteur ; Kåre Jørgensen, Auteur ; Poul Bach, Auteur Année de publication : 2009 Article en page(s) : pp. 3657–3664 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Spray drying Biotechnological industries Carbohydrates Morphology analysisDrying rate Résumé : An experimental investigation of the spray drying behavior of droplets containing excipients and carrier materials used in the pharmaceutical and biotechnological industries has been conducted. Specifically, rice starch suspensions with different amounts of TiO2, maltodextrin, dextrin, NaCl and Na2SO4 are dried. The drying rate is measured, and the morphology formation is mapped to obtain a more fundamental understanding of the drying process, which is very useful when designing product formulations. In the pilot spray dryer, droplet generation is based on the JetCutter technology and the droplets are dried under well-defined temperature and flow conditions. The droplets are sampled during drying to determine the drying rate, and the dried particles are collected for morphology analysis. The results show that reducing the water activity in a suspension of insolubles by adding various amounts of inorganic salts or carbohydrates causes an increase in the droplet temperature during spray drying resulting in a rather constant the drying rate. Further, the results show that small alterations in the droplet composition may significantly change the final particle morphology. The observed morphologies are discussed in detail. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800983w
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3657–3664[article] Spray drying of suspensions for pharma and bio products : drying kinetics and morphology [texte imprimé] / Jakob Sloth, Auteur ; Kåre Jørgensen, Auteur ; Poul Bach, Auteur . - 2009 . - pp. 3657–3664.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3657–3664
Mots-clés : Spray drying Biotechnological industries Carbohydrates Morphology analysisDrying rate Résumé : An experimental investigation of the spray drying behavior of droplets containing excipients and carrier materials used in the pharmaceutical and biotechnological industries has been conducted. Specifically, rice starch suspensions with different amounts of TiO2, maltodextrin, dextrin, NaCl and Na2SO4 are dried. The drying rate is measured, and the morphology formation is mapped to obtain a more fundamental understanding of the drying process, which is very useful when designing product formulations. In the pilot spray dryer, droplet generation is based on the JetCutter technology and the droplets are dried under well-defined temperature and flow conditions. The droplets are sampled during drying to determine the drying rate, and the dried particles are collected for morphology analysis. The results show that reducing the water activity in a suspension of insolubles by adding various amounts of inorganic salts or carbohydrates causes an increase in the droplet temperature during spray drying resulting in a rather constant the drying rate. Further, the results show that small alterations in the droplet composition may significantly change the final particle morphology. The observed morphologies are discussed in detail. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800983w Exemplaires
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Titre : Efficient resolution of the Colebrook equation Type de document : texte imprimé Auteurs : Didier Clamond, Auteur Année de publication : 2009 Article en page(s) : pp. 3665–3671 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Colebrook-like equations Lambert W-function Matlab FORTRAN codes Résumé : A robust, fast, and accurate method for solving the Colebrook-like equations is presented. The algorithm is efficient for the whole range of parameters involved in the Colebrook equation. The computations are not more demanding than simplified approximations, but they are much more accurate. The algorithm is also faster and more robust than the Colebrook solution expressed in term of the Lambert W-function. Matlab and FORTRAN codes are provided. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801626g
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3665–3671[article] Efficient resolution of the Colebrook equation [texte imprimé] / Didier Clamond, Auteur . - 2009 . - pp. 3665–3671.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3665–3671
Mots-clés : Colebrook-like equations Lambert W-function Matlab FORTRAN codes Résumé : A robust, fast, and accurate method for solving the Colebrook-like equations is presented. The algorithm is efficient for the whole range of parameters involved in the Colebrook equation. The computations are not more demanding than simplified approximations, but they are much more accurate. The algorithm is also faster and more robust than the Colebrook solution expressed in term of the Lambert W-function. Matlab and FORTRAN codes are provided. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801626g Exemplaires
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Titre : Internal treatment of process waters in paper production by dissolved air flotation with newly developed chemicals. 2. Field trials Type de document : texte imprimé Auteurs : Ruben Miranda, Auteur ; Carlos Negro, Auteur ; Angeles Blanco, Auteur Année de publication : 2009 Article en page(s) : pp. 3672–3677 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Inorganic polyaluminium salts Organic cationic polyelectrolytes Dissolved air flotation Résumé : New chemicals, based on the synergistic effect between inorganic polyaluminium salts and organic cationic polyelectrolytes, have been tested previously at laboratory-scale, and the most efficient product has been selected for an industrial trial for a dissolved air flotation unit of a paper mill based on 100% recovered paper (part 1 of this work). A polyaluminium nitrate sulfate salt combined with a quaternary polyamine has been evaluated in a long-term industrial trial for assessing its potential benefits. Results indicate that this new chemical is able to improve the removal of contaminants by dissolved air flotation, especially when the contamination load of the waters is high, allowing a further closure of the water circuits. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801826m
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3672–3677[article] Internal treatment of process waters in paper production by dissolved air flotation with newly developed chemicals. 2. Field trials [texte imprimé] / Ruben Miranda, Auteur ; Carlos Negro, Auteur ; Angeles Blanco, Auteur . - 2009 . - pp. 3672–3677.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3672–3677
Mots-clés : Inorganic polyaluminium salts Organic cationic polyelectrolytes Dissolved air flotation Résumé : New chemicals, based on the synergistic effect between inorganic polyaluminium salts and organic cationic polyelectrolytes, have been tested previously at laboratory-scale, and the most efficient product has been selected for an industrial trial for a dissolved air flotation unit of a paper mill based on 100% recovered paper (part 1 of this work). A polyaluminium nitrate sulfate salt combined with a quaternary polyamine has been evaluated in a long-term industrial trial for assessing its potential benefits. Results indicate that this new chemical is able to improve the removal of contaminants by dissolved air flotation, especially when the contamination load of the waters is high, allowing a further closure of the water circuits. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801826m Exemplaires
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Titre : Nonequilibrium reactive mole fraction curve maps Type de document : texte imprimé Auteurs : Gerardo Ruiz, Auteur ; Lakshmi N. Sridhar, Auteur Année de publication : 2009 Article en page(s) : pp. 3678–3684 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Nonequilibrium composition curve Reactive separation Mass transfer Differential algebraic equation Résumé : In this research and development (R&D) note, we derive new expressions to calculate the nonequilibrium composition curve maps for reactive separation processes incorporating mass transfer effects. The strategy to solve the differential algebraic equation (DAE) system to find the nonequilibrium reactive mole fraction curves is discussed and illustrated for the methyl tert-butyl ether (MTBE) and tertiary amyl methyl ether (TAME) synthesis problems. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8013082
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3678–3684[article] Nonequilibrium reactive mole fraction curve maps [texte imprimé] / Gerardo Ruiz, Auteur ; Lakshmi N. Sridhar, Auteur . - 2009 . - pp. 3678–3684.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3678–3684
Mots-clés : Nonequilibrium composition curve Reactive separation Mass transfer Differential algebraic equation Résumé : In this research and development (R&D) note, we derive new expressions to calculate the nonequilibrium composition curve maps for reactive separation processes incorporating mass transfer effects. The strategy to solve the differential algebraic equation (DAE) system to find the nonequilibrium reactive mole fraction curves is discussed and illustrated for the methyl tert-butyl ether (MTBE) and tertiary amyl methyl ether (TAME) synthesis problems. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8013082 Exemplaires
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Titre : Esterification of salicylic acid with dimethyl carbonate over mesoporous aluminosilicate Type de document : texte imprimé Auteurs : Xiaowei Su, Auteur ; Junping Li, Auteur ; Fukui Xiao, Auteur Année de publication : 2009 Article en page(s) : pp. 3685–3691 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Methyl salicylate Salicylic acid Dimethyl carbonate Mesoporous aluminosilicate Résumé : The synthesis of methyl salicylate (MS) from salicylic acid (SA) and dimethyl carbonate (DMC) was performed over a series of mesoporous aluminosilicates. The results showed that mesoporous aluminosilicate was an effective esterification catalyst for the reaction. It was also found that both SA conversion and MS selectivity were closely linked with the intermediate strong acidity and Lewis acidity of catalysts. As a result, the synergistic mechanism was proposed for the esterification of SA with DMC over a mesoporous aluminosilicate. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801148v
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3685–3691[article] Esterification of salicylic acid with dimethyl carbonate over mesoporous aluminosilicate [texte imprimé] / Xiaowei Su, Auteur ; Junping Li, Auteur ; Fukui Xiao, Auteur . - 2009 . - pp. 3685–3691.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3685–3691
Mots-clés : Methyl salicylate Salicylic acid Dimethyl carbonate Mesoporous aluminosilicate Résumé : The synthesis of methyl salicylate (MS) from salicylic acid (SA) and dimethyl carbonate (DMC) was performed over a series of mesoporous aluminosilicates. The results showed that mesoporous aluminosilicate was an effective esterification catalyst for the reaction. It was also found that both SA conversion and MS selectivity were closely linked with the intermediate strong acidity and Lewis acidity of catalysts. As a result, the synergistic mechanism was proposed for the esterification of SA with DMC over a mesoporous aluminosilicate. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801148v Exemplaires
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Titre : Natural convection mass transfer behavior of fixed bed of spheres in relation to catalytic and electrochemical reactor design Type de document : texte imprimé Auteurs : Ibrahim Hassan, Auteur ; Inderjit Nirdosh, Auteur ; Gomaa H. Sedahmed, Auteur Année de publication : 2009 Article en page(s) : pp. 3692–3695 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Convection mass transfer Spheres Electrochemical reactor Résumé : The free convection mass transfer behavior of a fixed bed of spheres has been studied experimentally using an electrochemical technique which involved measuring the limiting current of the cathodic deposition of copper from acidified copper sulfate solution. Variables studied were sphere diameter, bed height, and physical properties of the solution. The mass transfer coefficient was found to decrease slightly with increasing bed height and independent of sphere diameter. The data were correlated for the conditions 5 × 106 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801195b
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3692–3695[article] Natural convection mass transfer behavior of fixed bed of spheres in relation to catalytic and electrochemical reactor design [texte imprimé] / Ibrahim Hassan, Auteur ; Inderjit Nirdosh, Auteur ; Gomaa H. Sedahmed, Auteur . - 2009 . - pp. 3692–3695.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3692–3695
Mots-clés : Convection mass transfer Spheres Electrochemical reactor Résumé : The free convection mass transfer behavior of a fixed bed of spheres has been studied experimentally using an electrochemical technique which involved measuring the limiting current of the cathodic deposition of copper from acidified copper sulfate solution. Variables studied were sphere diameter, bed height, and physical properties of the solution. The mass transfer coefficient was found to decrease slightly with increasing bed height and independent of sphere diameter. The data were correlated for the conditions 5 × 106 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801195b Exemplaires
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Titre : Oxygen mass transfer correlations for pure and salt water in a well-mixed vessel Type de document : texte imprimé Auteurs : Gordon A. Hill, Auteur Année de publication : 2009 Article en page(s) : pp. 3696–3699 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Oxygen mass transfer Reverse osmosis Salt water Well-mixed vessel Résumé : The mass transfer rates of oxygen from air bubbles into both reverse osmosis (RO) and salt water (2.85% NaCl by mass) inside a baffled, well-mixed vessel have been investigated. Low aeration rates and impeller speeds were selected according to the Central Composite Rotatable Design (CCRD) experimental design approach. Empirical correlations with less than ±3% average prediction errors have been developed. Using identical operating conditions, the rate of oxygen transfer into pure RO water was significantly faster than that into salt water, with mass transfer coefficients ranging between 5.6 and 16.3 1/h for RO water and 4.4 and 14.7 1/h for salt water. The lower rates of oxygen transfer for salt water are hypothesized to be due to increased viscosity and correspondingly reduced diffusion in the boundary layer. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8019906
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3696–3699[article] Oxygen mass transfer correlations for pure and salt water in a well-mixed vessel [texte imprimé] / Gordon A. Hill, Auteur . - 2009 . - pp. 3696–3699.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3696–3699
Mots-clés : Oxygen mass transfer Reverse osmosis Salt water Well-mixed vessel Résumé : The mass transfer rates of oxygen from air bubbles into both reverse osmosis (RO) and salt water (2.85% NaCl by mass) inside a baffled, well-mixed vessel have been investigated. Low aeration rates and impeller speeds were selected according to the Central Composite Rotatable Design (CCRD) experimental design approach. Empirical correlations with less than ±3% average prediction errors have been developed. Using identical operating conditions, the rate of oxygen transfer into pure RO water was significantly faster than that into salt water, with mass transfer coefficients ranging between 5.6 and 16.3 1/h for RO water and 4.4 and 14.7 1/h for salt water. The lower rates of oxygen transfer for salt water are hypothesized to be due to increased viscosity and correspondingly reduced diffusion in the boundary layer. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8019906 Exemplaires
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Titre : CO2/N2 reverse selective gas separation membranes : technological opportunities and scientific challenges Type de document : texte imprimé Auteurs : Eric Favre, Auteur ; Denis Roizard, Auteur ; Roda Bounaceur, Auteur Année de publication : 2009 Article en page(s) : pp. 3700–3701 Note générale : Chemical engineering Langues : Anglais (eng) Note de contenu : Correspondence En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801923w
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3700–3701[article] CO2/N2 reverse selective gas separation membranes : technological opportunities and scientific challenges [texte imprimé] / Eric Favre, Auteur ; Denis Roizard, Auteur ; Roda Bounaceur, Auteur . - 2009 . - pp. 3700–3701.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3700–3701
Note de contenu : Correspondence En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801923w Exemplaires
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Titre : Comments on the origins of N2/CO2 selectivity of gas separation membranes Type de document : texte imprimé Auteurs : Parveen Kumar, Auteur ; Sangil Kim, Auteur ; Junichi Ida, Auteur Année de publication : 2009 Article en page(s) : p. 3702 Note générale : Chemical engineering Langues : Anglais (eng) Note de contenu : Correspondence En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9001487
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - p. 3702[article] Comments on the origins of N2/CO2 selectivity of gas separation membranes [texte imprimé] / Parveen Kumar, Auteur ; Sangil Kim, Auteur ; Junichi Ida, Auteur . - 2009 . - p. 3702.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - p. 3702
Note de contenu : Correspondence En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9001487 Exemplaires
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