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Vol. 48 N° 24 - Décembre 2009 [texte imprimé] . - 2010 . - p. 10751–11240 : ill. ; 28 cm. Chemical engineering Langues : Anglais (eng)
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Ajouter le résultat dans votre panierIntumescent flame retardation of starch containing polypropylene semibiocomposites / Shibin Nie in Industrial & engineering chemistry research, Vol. 48 N° 24 (Décembre 2009)
inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10751–10758
Titre : Intumescent flame retardation of starch containing polypropylene semibiocomposites : flame retardancy and thermal degradation Type de document : texte imprimé Auteurs : Shibin Nie, Auteur ; Lei Song, Auteur ; Yuqiang Guo, Auteur Année de publication : 2010 Article en page(s) : pp. 10751–10758 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Starch containing polypropylene semibiocomposites Microencapsulated ammonium polyphosphate Résumé : Starch containing polypropylene (SCP) semibiocomposites were prepared by melted blend method. Microencapsulated ammonium polyphosphate (MCAPP) was added to the SCP not only to improve its flame retardant properties but also to restrain the reaction between ammonium polyphosphate (APP) and starch during processing. The flame retardant properties of SCP have been investigated by limited oxygen index (LOI), UL-94 test, and cone calorimeter test. The results of cone calorimeter show that the peak of heat release rate and total heat release of SCP decreases substantially compared with that of pure PP. The thermal degradation and gas products of PP/starch/MCAPP systems were monitored by thermogravimetric analysis (TGA) and thermogravimetric analysis−infrared spectrometry (TG-IR). Scanning electron micrograph (SEM) and X-ray photoelectron spectroscopy (XPS) measurements were utilized to investigate the chemical structure, as well as the surface morphology of the residual char. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9012198 [article] Intumescent flame retardation of starch containing polypropylene semibiocomposites : flame retardancy and thermal degradation [texte imprimé] / Shibin Nie, Auteur ; Lei Song, Auteur ; Yuqiang Guo, Auteur . - 2010 . - pp. 10751–10758.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10751–10758
Mots-clés : Starch containing polypropylene semibiocomposites Microencapsulated ammonium polyphosphate Résumé : Starch containing polypropylene (SCP) semibiocomposites were prepared by melted blend method. Microencapsulated ammonium polyphosphate (MCAPP) was added to the SCP not only to improve its flame retardant properties but also to restrain the reaction between ammonium polyphosphate (APP) and starch during processing. The flame retardant properties of SCP have been investigated by limited oxygen index (LOI), UL-94 test, and cone calorimeter test. The results of cone calorimeter show that the peak of heat release rate and total heat release of SCP decreases substantially compared with that of pure PP. The thermal degradation and gas products of PP/starch/MCAPP systems were monitored by thermogravimetric analysis (TGA) and thermogravimetric analysis−infrared spectrometry (TG-IR). Scanning electron micrograph (SEM) and X-ray photoelectron spectroscopy (XPS) measurements were utilized to investigate the chemical structure, as well as the surface morphology of the residual char. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9012198 Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10759–10764
Titre : Phase-transfer catalyzed esterification of brominated poly(isobutylene-co-isoprene) Type de document : texte imprimé Auteurs : J. Keith McLean, Auteur ; Sergio A. Guillén-Castellanos, Auteur ; J. Scott Parent, Auteur Année de publication : 2010 Article en page(s) : pp. 10759–10764 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Brominated poly(isobutylene-co-isoprene) Carboxylate nucleophiles Phase-transfer techniques Résumé : Phase-transfer techniques are used to activate carboxylate nucleophiles for the purpose of preparing ester derivatives of brominated poly(isobutylene-co-isoprene) (BIIR). Studies of the dynamics and yields of stearate ester syntheses reveal the dual role of tetrabutylammonium bromide, as it serves as a phase-transfer catalyst and a catalyst for the isomerization of exomethylene allylic bromide functionality to kinetically more reactive E,Z-BrMe isomers. Knowledge of reaction fundamentals are used to prepare copolymers from BIIR and carboxylate-terminated polybutadiene (cBR) that phase-partition in the manner required for blend compatibilization applications. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901284j [article] Phase-transfer catalyzed esterification of brominated poly(isobutylene-co-isoprene) [texte imprimé] / J. Keith McLean, Auteur ; Sergio A. Guillén-Castellanos, Auteur ; J. Scott Parent, Auteur . - 2010 . - pp. 10759–10764.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10759–10764
Mots-clés : Brominated poly(isobutylene-co-isoprene) Carboxylate nucleophiles Phase-transfer techniques Résumé : Phase-transfer techniques are used to activate carboxylate nucleophiles for the purpose of preparing ester derivatives of brominated poly(isobutylene-co-isoprene) (BIIR). Studies of the dynamics and yields of stearate ester syntheses reveal the dual role of tetrabutylammonium bromide, as it serves as a phase-transfer catalyst and a catalyst for the isomerization of exomethylene allylic bromide functionality to kinetically more reactive E,Z-BrMe isomers. Knowledge of reaction fundamentals are used to prepare copolymers from BIIR and carboxylate-terminated polybutadiene (cBR) that phase-partition in the manner required for blend compatibilization applications. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901284j Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10765–10770
Titre : Synthesis and characterization of CaO nanopods for high temperature CO2 capture Type de document : texte imprimé Auteurs : Zeheng Yang, Auteur ; Ming Zhao, Auteur ; Nicholas H. Florin, Auteur Année de publication : 2010 Article en page(s) : pp. 10765–10770 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : CaO sorbent CO2 absorption Good cyclic performance Résumé : A hollow structured CaO sorbent with high CO2 absorption capacity and good cyclic performance at high temperatures was derived from the corresponding CaCO3 precursor, which was prepared by bubbling gaseous CO2 through a Ca(OH)2 slurry in the presence of the triblock copolymer surfactant, P123 (PEO20PPO70PEO20). Field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images showed the novel sorbent to be comprised of nanosized platelets forming hollow particles resembling a pod of approximately 200 nm in diameter and up to 600 nm in length. Thermogravimetric analysis showed that the tailored sorbent had the highest CO2 absorption capacity when compared with calcines derived from precipitated CaCO3 without P123 and a commercially available CaCO3, retaining >50% CO2 absorption capacity after 50 CO2 capture-and-release cycles for carbonation temperatures from 600 to 700 °C. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901137s [article] Synthesis and characterization of CaO nanopods for high temperature CO2 capture [texte imprimé] / Zeheng Yang, Auteur ; Ming Zhao, Auteur ; Nicholas H. Florin, Auteur . - 2010 . - pp. 10765–10770.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10765–10770
Mots-clés : CaO sorbent CO2 absorption Good cyclic performance Résumé : A hollow structured CaO sorbent with high CO2 absorption capacity and good cyclic performance at high temperatures was derived from the corresponding CaCO3 precursor, which was prepared by bubbling gaseous CO2 through a Ca(OH)2 slurry in the presence of the triblock copolymer surfactant, P123 (PEO20PPO70PEO20). Field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images showed the novel sorbent to be comprised of nanosized platelets forming hollow particles resembling a pod of approximately 200 nm in diameter and up to 600 nm in length. Thermogravimetric analysis showed that the tailored sorbent had the highest CO2 absorption capacity when compared with calcines derived from precipitated CaCO3 without P123 and a commercially available CaCO3, retaining >50% CO2 absorption capacity after 50 CO2 capture-and-release cycles for carbonation temperatures from 600 to 700 °C. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901137s Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10771–10778
Titre : Enhanced photocatalytic activity of Ag3VO4 loaded with rare-earth elements under visible-light irradiation Type de document : texte imprimé Auteurs : Hui Xu, Auteur ; Huaming Li, Auteur ; Xu, Li, Auteur Année de publication : 2010 Article en page(s) : pp. 10771–10778 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Rare-earth element Wetness impregnation technique Photocatalytic activities Résumé : Rare-earth-loaded Ag3VO4 catalysts (RE3+-Ag3VO4, RE = Nd, Sm, and Eu) were prepared by the wetness impregnation technique and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), diffuse reflectance spectroscopy (DRS), and X-ray photoelectron spectroscopy (XPS). The photocatalytic activities of the samples were evaluated by rhodamine B (RhB) dye degradation under visible-light irradiation. It was found that the presence of rare-earth oxides in the host Ag3VO4 could decrease the band gap and accelerate the separation of photogenerated electron−hole pairs, which led to higher photocatalytic activities. Among the rare-earth-loaded samples, Nd3+-loaded Ag3VO4 catalyst showed the highest photocatalytic activity. The optimum contents of Nd3+, Eu3+, and Sm3+ were found to be 2, 3, and 2 wt %, respectively. It was also found that the photocatalytic degradation of RhB over RE3+-Ag3VO4 (2 wt %) followed pseudo-first-order kinetics. A possible mechanism for RhB photocatalytic degradation over RE3+-Ag3VO4 catalysts is also proposed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900835g [article] Enhanced photocatalytic activity of Ag3VO4 loaded with rare-earth elements under visible-light irradiation [texte imprimé] / Hui Xu, Auteur ; Huaming Li, Auteur ; Xu, Li, Auteur . - 2010 . - pp. 10771–10778.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10771–10778
Mots-clés : Rare-earth element Wetness impregnation technique Photocatalytic activities Résumé : Rare-earth-loaded Ag3VO4 catalysts (RE3+-Ag3VO4, RE = Nd, Sm, and Eu) were prepared by the wetness impregnation technique and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), diffuse reflectance spectroscopy (DRS), and X-ray photoelectron spectroscopy (XPS). The photocatalytic activities of the samples were evaluated by rhodamine B (RhB) dye degradation under visible-light irradiation. It was found that the presence of rare-earth oxides in the host Ag3VO4 could decrease the band gap and accelerate the separation of photogenerated electron−hole pairs, which led to higher photocatalytic activities. Among the rare-earth-loaded samples, Nd3+-loaded Ag3VO4 catalyst showed the highest photocatalytic activity. The optimum contents of Nd3+, Eu3+, and Sm3+ were found to be 2, 3, and 2 wt %, respectively. It was also found that the photocatalytic degradation of RhB over RE3+-Ag3VO4 (2 wt %) followed pseudo-first-order kinetics. A possible mechanism for RhB photocatalytic degradation over RE3+-Ag3VO4 catalysts is also proposed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900835g Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10779–10787
Titre : Design of a reactive distillation column for direct preparation of dichloropropanol from glycerol Type de document : texte imprimé Auteurs : Zheng-Hong Luo, Auteur ; Xiao-Zi You, Auteur ; Jie Zhong, Auteur Année de publication : 2010 Article en page(s) : pp. 10779–10787 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Dichloropropanol Glycerol Reactive distillation column Résumé : In the present study, a reactor design for the direct preparation of dichloropropanol (DCP) from glycerol (GLY) is presented. As an optimum design, a reactive distillation (RD) column in which the second chlorination of GLY occurs during the direct preparation of DCP from GLY has been introduced. Using a simple equilibrium mathematical model of RD, a pilot plant scale column is designed. Furthermore, the whole preparation process of DCP from GLY used the optimum RD column as the central unit is simulated by using an advanced software tool, namely ASPEN PLUS. The pilot plant realization of the whole preparation process is presented and its results are compared with the theoretical prediction. On the basis of the pilot plant data and simulated results, a new technology of DCP production has been designed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900933b [article] Design of a reactive distillation column for direct preparation of dichloropropanol from glycerol [texte imprimé] / Zheng-Hong Luo, Auteur ; Xiao-Zi You, Auteur ; Jie Zhong, Auteur . - 2010 . - pp. 10779–10787.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10779–10787
Mots-clés : Dichloropropanol Glycerol Reactive distillation column Résumé : In the present study, a reactor design for the direct preparation of dichloropropanol (DCP) from glycerol (GLY) is presented. As an optimum design, a reactive distillation (RD) column in which the second chlorination of GLY occurs during the direct preparation of DCP from GLY has been introduced. Using a simple equilibrium mathematical model of RD, a pilot plant scale column is designed. Furthermore, the whole preparation process of DCP from GLY used the optimum RD column as the central unit is simulated by using an advanced software tool, namely ASPEN PLUS. The pilot plant realization of the whole preparation process is presented and its results are compared with the theoretical prediction. On the basis of the pilot plant data and simulated results, a new technology of DCP production has been designed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900933b Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10788–10795
Titre : Catalytic conversion of ethylene to propylene and butenes over H−ZSM-5 Type de document : texte imprimé Auteurs : Baomin Lin, Auteur ; Qinghong Zhang, Auteur ; Ye Wang, Auteur Année de publication : 2010 Article en page(s) : pp. 10788–10795 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ethylene Propylene Butenes Catalytic conversion Résumé : Among 11 kinds of molecular sieves examined, H−ZSM-5 exhibited the highest activity for the direct conversion of ethylene to propylene. The conversion of ethylene was 58% and the selectivities to propylene and butenes were 42% and 21%, respectively, over H−ZSM-5 at 723 K. Our studies demonstrate that the conversion of ethylene increases with the degree of H+ exchange in the H−Na−ZSM-5 series of samples with different H+ exchange degrees and the Al content in the H−ZSM-5 samples with different Si/Al ratios. The strong Brønsted acid sites are proposed to account for the conversion of ethylene. The modification of H−ZSM-5 with phosphorus or boron could enhance the selectivity of propylene but decreased the conversion of ethylene due to the decreased acidity. In situ FT-IR studies confirm the reaction of ethylene molecules with the Brønsted acid sites associated with −Si−(OH)−Al− groups. In situ FT-IR results further suggest the occurrence of oligomerization of ethylene on the surface of H−ZSM-5. We speculate that the cracking of the oligomeric intermediates may lead to the formation of propylene. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901227p [article] Catalytic conversion of ethylene to propylene and butenes over H−ZSM-5 [texte imprimé] / Baomin Lin, Auteur ; Qinghong Zhang, Auteur ; Ye Wang, Auteur . - 2010 . - pp. 10788–10795.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10788–10795
Mots-clés : Ethylene Propylene Butenes Catalytic conversion Résumé : Among 11 kinds of molecular sieves examined, H−ZSM-5 exhibited the highest activity for the direct conversion of ethylene to propylene. The conversion of ethylene was 58% and the selectivities to propylene and butenes were 42% and 21%, respectively, over H−ZSM-5 at 723 K. Our studies demonstrate that the conversion of ethylene increases with the degree of H+ exchange in the H−Na−ZSM-5 series of samples with different H+ exchange degrees and the Al content in the H−ZSM-5 samples with different Si/Al ratios. The strong Brønsted acid sites are proposed to account for the conversion of ethylene. The modification of H−ZSM-5 with phosphorus or boron could enhance the selectivity of propylene but decreased the conversion of ethylene due to the decreased acidity. In situ FT-IR studies confirm the reaction of ethylene molecules with the Brønsted acid sites associated with −Si−(OH)−Al− groups. In situ FT-IR results further suggest the occurrence of oligomerization of ethylene on the surface of H−ZSM-5. We speculate that the cracking of the oligomeric intermediates may lead to the formation of propylene. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901227p Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10796–10802
Titre : Formation of synthesis gas from propane oxidation over pt-on-ceria : effect of ceria surface area, reaction temperature, and oxygen/fuel ratio Type de document : texte imprimé Auteurs : Tapan K. Das, Auteur ; Edwin L. Kugler, Auteur ; Dady B. Dadyburjor, Auteur Année de publication : 2010 Article en page(s) : pp. 10796–10802 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Synthesis gas Propane oxidation Ceria surface Temperature Résumé : The formation of synthesis gas from propane oxidation has been investigated on 1.0% Pt/CeO2 catalysts in a fixed-bed flow reactor over a temperature range of 200−800 °C at atmospheric pressure using ∼90% inert. Three kinds of ceria, with different surface areas, have been used as the catalytic support for this reaction. The catalysts were characterized using X-ray diffraction (XRD), temperature-programmed reduction (TPR), temperature-programmed oxidation (TPO), H2 chemisorption, and BET surface area. For the catalysts with the highest surface area, a large decrease in BET surface area has been observed after calcinations at high temperature. The oxidation of propane occurs with two sets of products. At low temperatures (T ≤ 500 °C), propane oxidizes exclusively into CO2 and H2O with little H2. Above 500 °C, O2 is completely consumed, and the selectivities of CO and H2 increase steadily with increase in temperature. In the region 500−700 °C, high-surface-area catalysts show higher activity and selectivity to H2 and CO than low-surface-area catalysts. Propane conversion at high temperatures (T ≥ 750 °C) is similar for all the catalysts. The effect of O2/C3H8 has also been investigated. Propane conversion and carbon dioxide selectivity increase, and H2 and CO selectivities decrease, with increase in the O2/C3H8 ratio. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900441d [article] Formation of synthesis gas from propane oxidation over pt-on-ceria : effect of ceria surface area, reaction temperature, and oxygen/fuel ratio [texte imprimé] / Tapan K. Das, Auteur ; Edwin L. Kugler, Auteur ; Dady B. Dadyburjor, Auteur . - 2010 . - pp. 10796–10802.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10796–10802
Mots-clés : Synthesis gas Propane oxidation Ceria surface Temperature Résumé : The formation of synthesis gas from propane oxidation has been investigated on 1.0% Pt/CeO2 catalysts in a fixed-bed flow reactor over a temperature range of 200−800 °C at atmospheric pressure using ∼90% inert. Three kinds of ceria, with different surface areas, have been used as the catalytic support for this reaction. The catalysts were characterized using X-ray diffraction (XRD), temperature-programmed reduction (TPR), temperature-programmed oxidation (TPO), H2 chemisorption, and BET surface area. For the catalysts with the highest surface area, a large decrease in BET surface area has been observed after calcinations at high temperature. The oxidation of propane occurs with two sets of products. At low temperatures (T ≤ 500 °C), propane oxidizes exclusively into CO2 and H2O with little H2. Above 500 °C, O2 is completely consumed, and the selectivities of CO and H2 increase steadily with increase in temperature. In the region 500−700 °C, high-surface-area catalysts show higher activity and selectivity to H2 and CO than low-surface-area catalysts. Propane conversion at high temperatures (T ≥ 750 °C) is similar for all the catalysts. The effect of O2/C3H8 has also been investigated. Propane conversion and carbon dioxide selectivity increase, and H2 and CO selectivities decrease, with increase in the O2/C3H8 ratio. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900441d Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10803–10809
Titre : UDCaT-5 : a novel mesoporous superacid catalyst in the selective synthesis of linear phenyldodecanes by the alkylation of benzene with 1-dodecene Type de document : texte imprimé Auteurs : Ganapati D. Yadav, Auteur ; Mumtarul I. N. I. Siddiqui, Auteur Année de publication : 2010 Article en page(s) : pp. 10803–10809 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Novel mesoporous superacidic catalyst UDCaT-5 Benzene Alkylation Kinetic model Résumé : LAB are important intermediates used in the detergency sector and are typically manufactured by the alkylation of benzene and α-olefin using highly corrosive, polluting, and dangerous Lewis and Bronsted acids such as AlCl3 and HF. The position of phenyl group and the alkyl chain length are important factors in determining surface active properties and biodegradability of linear alkylbenzene sulfonates (LABS) prepared from LAB. LAB isomer distribution depends strongly on the type and nature of the catalyst and reaction conditions. In this paper, we report the novel mesoporous superacidic catalyst UDCaT-5 developed in our laboratory, which exhibits remarkable activity, selectivity, and stability for the alkylation of benzene using 1-dodecene. Also to get a greater insight into the mechanism and to develop a suitable kinetic model, the parallel reaction of dimerization of 1-dodecene, although insignificant, was also studied indepedently. A systematic investigation of the effects of various operating parameters was accomplished and the best parameters were established. Furthermore, a kinetic model was developed and validated against experimental data. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900610b [article] UDCaT-5 : a novel mesoporous superacid catalyst in the selective synthesis of linear phenyldodecanes by the alkylation of benzene with 1-dodecene [texte imprimé] / Ganapati D. Yadav, Auteur ; Mumtarul I. N. I. Siddiqui, Auteur . - 2010 . - pp. 10803–10809.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10803–10809
Mots-clés : Novel mesoporous superacidic catalyst UDCaT-5 Benzene Alkylation Kinetic model Résumé : LAB are important intermediates used in the detergency sector and are typically manufactured by the alkylation of benzene and α-olefin using highly corrosive, polluting, and dangerous Lewis and Bronsted acids such as AlCl3 and HF. The position of phenyl group and the alkyl chain length are important factors in determining surface active properties and biodegradability of linear alkylbenzene sulfonates (LABS) prepared from LAB. LAB isomer distribution depends strongly on the type and nature of the catalyst and reaction conditions. In this paper, we report the novel mesoporous superacidic catalyst UDCaT-5 developed in our laboratory, which exhibits remarkable activity, selectivity, and stability for the alkylation of benzene using 1-dodecene. Also to get a greater insight into the mechanism and to develop a suitable kinetic model, the parallel reaction of dimerization of 1-dodecene, although insignificant, was also studied indepedently. A systematic investigation of the effects of various operating parameters was accomplished and the best parameters were established. Furthermore, a kinetic model was developed and validated against experimental data. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900610b Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10810–10815
Titre : Kinetic and stability study of the peroxidase inhibition in ionic liquids Type de document : texte imprimé Auteurs : Aristides P. Carneiro, Auteur ; Oscar Rodriguez, Auteur ; Fatima L. Mota, Auteur Année de publication : 2010 Article en page(s) : pp. 10810–10815 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ionic liquids Peroxidase Kinetic study Stability Résumé : The activity and stability of peroxidase in aqueous solutions of two ionic liquids (ILs) have been studied. The ILs selected were 1-ethyl-3-methylimidazolium 2-(2-methoxyethoxy) ethylsulfate, [emim][MDEGSO4], and 1-ethyl-3-methylimidazolium ethylsulfate, [emim][EtSO4]. Experiments were performed at room temperature using concentrations of ILs between 5 and 50% (v/v) and pH values in the range from 5 to 9. The initial activity of the enzyme in these ILs at optimized conditions (pH 7 and 5−10% IL) was similar or higher than that achieved with buffer solution. Kinetic studies showed that maximum reaction velocity (Vmax) decreased with increasing concentration of IL. The effect of [emim][EtSO4] concentration on the decrease of Vmax was higher than that of [emim][MDEGSO4]. It was found that [emim][EtSO4] was a more potent inhibitor on peroxidase activity. The peroxidase studied was active in the ILs investigated, and the enzyme exhibited a higher stability in ILs at the optimized conditions. Kinetic studies showed that inhibition was a noncompetitive type in both ILs. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9007612 [article] Kinetic and stability study of the peroxidase inhibition in ionic liquids [texte imprimé] / Aristides P. Carneiro, Auteur ; Oscar Rodriguez, Auteur ; Fatima L. Mota, Auteur . - 2010 . - pp. 10810–10815.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10810–10815
Mots-clés : Ionic liquids Peroxidase Kinetic study Stability Résumé : The activity and stability of peroxidase in aqueous solutions of two ionic liquids (ILs) have been studied. The ILs selected were 1-ethyl-3-methylimidazolium 2-(2-methoxyethoxy) ethylsulfate, [emim][MDEGSO4], and 1-ethyl-3-methylimidazolium ethylsulfate, [emim][EtSO4]. Experiments were performed at room temperature using concentrations of ILs between 5 and 50% (v/v) and pH values in the range from 5 to 9. The initial activity of the enzyme in these ILs at optimized conditions (pH 7 and 5−10% IL) was similar or higher than that achieved with buffer solution. Kinetic studies showed that maximum reaction velocity (Vmax) decreased with increasing concentration of IL. The effect of [emim][EtSO4] concentration on the decrease of Vmax was higher than that of [emim][MDEGSO4]. It was found that [emim][EtSO4] was a more potent inhibitor on peroxidase activity. The peroxidase studied was active in the ILs investigated, and the enzyme exhibited a higher stability in ILs at the optimized conditions. Kinetic studies showed that inhibition was a noncompetitive type in both ILs. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9007612 Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10816–10819
Titre : Influence of carbon chain length and unsaturation on the esterification activity of fatty acids on Nb2O5 catalyst Type de document : texte imprimé Auteurs : Kalaru Srilatha, Auteur ; N. Lingaiah, Auteur ; Potharaju S. Sai Prasad, Auteur Année de publication : 2010 Article en page(s) : pp. 10816–10819 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Chain length Carboxylic acids Nb2O5 catalyst Résumé : The influence of chain length and the extent of the saturation on the esterification activity of long chain carboxylic acids were studied on Nb2O5 catalyst. A series of individual fatty acids (caprylic, capric, lauric, myristic, palmitic, and steric acids) and their mixtures present in vegetable oils, namely, coconut oil, ground nut oil, olive oil, and soybean oil, were selected for esterification with methanol at different reaction temperatures. The esterification reactivity was found to be inversely proportional to alkyl chain length of the acid. The trend was discussed in terms of steric and inductive effects. The kinetic parameters estimated revealed a mild dependency of the activity on the extent of unsaturation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900864z [article] Influence of carbon chain length and unsaturation on the esterification activity of fatty acids on Nb2O5 catalyst [texte imprimé] / Kalaru Srilatha, Auteur ; N. Lingaiah, Auteur ; Potharaju S. Sai Prasad, Auteur . - 2010 . - pp. 10816–10819.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10816–10819
Mots-clés : Chain length Carboxylic acids Nb2O5 catalyst Résumé : The influence of chain length and the extent of the saturation on the esterification activity of long chain carboxylic acids were studied on Nb2O5 catalyst. A series of individual fatty acids (caprylic, capric, lauric, myristic, palmitic, and steric acids) and their mixtures present in vegetable oils, namely, coconut oil, ground nut oil, olive oil, and soybean oil, were selected for esterification with methanol at different reaction temperatures. The esterification reactivity was found to be inversely proportional to alkyl chain length of the acid. The trend was discussed in terms of steric and inductive effects. The kinetic parameters estimated revealed a mild dependency of the activity on the extent of unsaturation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900864z Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10820–10826
Titre : A new Dubinin-Radushkevich-modified BET combined equation to correlate with a single procedure the full relative pressure range of 77 K N2 isotherms of solids with different textural properties Type de document : texte imprimé Auteurs : Antonio Marcilla, Auteur ; Amparo Gómez-Siurana, Auteur ; Francisco J. Valdés, Auteur Année de publication : 2010 Article en page(s) : pp. 10820–10826 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Adsorption isotherm data Dubinin− Radushkevich equations BET Résumé : In this work, a model capable of adequately correlating and reproducing experimental adsorption isotherm data in the overall relative pressure range is suggested. The equation includes a Dubinin−Radushkevich term and a modified BET term that avoids the discontinuity of BET equation at high relative pressures. Thus, the typical independent application of the Dubinin−Radushkevich and BET equations, involving the need of a selection of the respective relative pressure range, is substituted by a single optimization procedure, permitting the calculation of the values of the parameters characterizing the textural properties of solids. The validity of the procedure has been checked through its application to several experimental examples, corresponding to types I, II, and IV isotherms, showing excellent results in all of the cases. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900912x [article] A new Dubinin-Radushkevich-modified BET combined equation to correlate with a single procedure the full relative pressure range of 77 K N2 isotherms of solids with different textural properties [texte imprimé] / Antonio Marcilla, Auteur ; Amparo Gómez-Siurana, Auteur ; Francisco J. Valdés, Auteur . - 2010 . - pp. 10820–10826.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10820–10826
Mots-clés : Adsorption isotherm data Dubinin− Radushkevich equations BET Résumé : In this work, a model capable of adequately correlating and reproducing experimental adsorption isotherm data in the overall relative pressure range is suggested. The equation includes a Dubinin−Radushkevich term and a modified BET term that avoids the discontinuity of BET equation at high relative pressures. Thus, the typical independent application of the Dubinin−Radushkevich and BET equations, involving the need of a selection of the respective relative pressure range, is substituted by a single optimization procedure, permitting the calculation of the values of the parameters characterizing the textural properties of solids. The validity of the procedure has been checked through its application to several experimental examples, corresponding to types I, II, and IV isotherms, showing excellent results in all of the cases. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900912x Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10827–10839
Titre : Modeling and control of sequence length distribution for controlled radical (RAFT) copolymerization Type de document : texte imprimé Auteurs : Yuesheng Ye, Auteur ; F. Joseph Schork, Auteur Année de publication : 2010 Article en page(s) : pp. 10827–10839 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Controlled/living radical polymerization RAFT copolymerization systems Résumé : Controlled/living radical polymerization (CRP) allows a high degree of control over polymeric molecular architecture with narrow molecular weight distributions and desired polymer properties. Although the control of copolymer composition for RAFT copolymerization systems in a semibatch reactor has been studied, the control of sequence length receives little attention. In this work, using moment equations, a chain model and a sequence model were developed to describe both chain and sequence properties such as chain and sequence lengths and their distributions, for RAFT copolymerization in semibatch operations. It is seen that a copolymer with constant composition or linear gradient composition can be obtained through an optimized feeding policy. With the sequence model, it was possible to show the sequence length and distributions while controlling constant composition or linear gradient composition. More importantly, it was demonstrated that sequence length distribution can be designed and controlled using the sequence model. The sequence model may be used as a theoretical tool to understand the importance of sequence length and distributions in CRP. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901032y [article] Modeling and control of sequence length distribution for controlled radical (RAFT) copolymerization [texte imprimé] / Yuesheng Ye, Auteur ; F. Joseph Schork, Auteur . - 2010 . - pp. 10827–10839.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10827–10839
Mots-clés : Controlled/living radical polymerization RAFT copolymerization systems Résumé : Controlled/living radical polymerization (CRP) allows a high degree of control over polymeric molecular architecture with narrow molecular weight distributions and desired polymer properties. Although the control of copolymer composition for RAFT copolymerization systems in a semibatch reactor has been studied, the control of sequence length receives little attention. In this work, using moment equations, a chain model and a sequence model were developed to describe both chain and sequence properties such as chain and sequence lengths and their distributions, for RAFT copolymerization in semibatch operations. It is seen that a copolymer with constant composition or linear gradient composition can be obtained through an optimized feeding policy. With the sequence model, it was possible to show the sequence length and distributions while controlling constant composition or linear gradient composition. More importantly, it was demonstrated that sequence length distribution can be designed and controlled using the sequence model. The sequence model may be used as a theoretical tool to understand the importance of sequence length and distributions in CRP. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901032y Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10840–10844
Titre : Kinetics of the hydration of ethylene oxide in the presence of heterogeneous catalyst Type de document : texte imprimé Auteurs : Mehmet Riza Altiokka, Auteur ; Sema Akyalçin, Auteur Année de publication : 2010 Article en page(s) : pp. 10840–10844 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ethylene oxideKinetic data Pressurized batch reactor Résumé : Kinetic data on the hydration of ethylene oxide was obtained from both uncatalyzed and heterogeneously catalyzed reactions using a pressurized batch reactor. Amberjet 4200/HCO3− was used as the heterogeneous catalyst, which was found to be the most effective among the four types of cross-linked styrene−divinylbenzene anion-exchange resins tested. The reactions were proved to follow a series-parallel irreversible homogeneous mechanism under both catalyzed and uncatalyzed conditions. Thus the corresponding rate expression can be given as −rEtO = k1CWCEtO + k2CMEGCEtO + k3CDEGCEtO. The rate constants were determined by applying the method of averages at different temperatures. The temperature dependency of the rate constants was found to be k1/[L/(mol·min)] = exp(13.62 − 8220/T), k2/[L/(mol·min)] = exp(15.57 − 8700/T), and k3/[L/(mol·min)] = exp(16.06 − 8900/T) for the uncatalyzed reactions and k1/[L/(mol·min)] = exp(19.60 − 9580/T), k2/[L/(mol·min)] = exp(20.19 − 10171/T), and k3/[L/(mol·min)] = exp(19.06 − 9743/T) in the presence of catalyst of 0.15 mol of HCO3−/L in equivalent, where T is the absolute temperature in kelvin. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901037w [article] Kinetics of the hydration of ethylene oxide in the presence of heterogeneous catalyst [texte imprimé] / Mehmet Riza Altiokka, Auteur ; Sema Akyalçin, Auteur . - 2010 . - pp. 10840–10844.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10840–10844
Mots-clés : Ethylene oxideKinetic data Pressurized batch reactor Résumé : Kinetic data on the hydration of ethylene oxide was obtained from both uncatalyzed and heterogeneously catalyzed reactions using a pressurized batch reactor. Amberjet 4200/HCO3− was used as the heterogeneous catalyst, which was found to be the most effective among the four types of cross-linked styrene−divinylbenzene anion-exchange resins tested. The reactions were proved to follow a series-parallel irreversible homogeneous mechanism under both catalyzed and uncatalyzed conditions. Thus the corresponding rate expression can be given as −rEtO = k1CWCEtO + k2CMEGCEtO + k3CDEGCEtO. The rate constants were determined by applying the method of averages at different temperatures. The temperature dependency of the rate constants was found to be k1/[L/(mol·min)] = exp(13.62 − 8220/T), k2/[L/(mol·min)] = exp(15.57 − 8700/T), and k3/[L/(mol·min)] = exp(16.06 − 8900/T) for the uncatalyzed reactions and k1/[L/(mol·min)] = exp(19.60 − 9580/T), k2/[L/(mol·min)] = exp(20.19 − 10171/T), and k3/[L/(mol·min)] = exp(19.06 − 9743/T) in the presence of catalyst of 0.15 mol of HCO3−/L in equivalent, where T is the absolute temperature in kelvin. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901037w Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10845–10849
Titre : CuCl/phen/NMI in homogeneous carbonylation for synthesis of diethyl carbonate : highly active catalyst and corrosion inhibitor Type de document : texte imprimé Auteurs : Hui Xiong, Auteur ; Wanling Mo, Auteur ; Jianglin Hu, Auteur Année de publication : 2010 Article en page(s) : pp. 10845–10849 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ethanol CuCl-catalyzed oxidative carbonylation N-donor ligands Résumé : The effects of N-donor ligands on CuCl-catalyzed oxidative carbonylation of ethanol were investigated. It was found that 1,10-phenanthroline (phen) and N-methyl imidazole (NMI) exhibited a synergic effect on the catalytic activity. Catalytic efficiency of the CuCl system was enhanced dramatically, and corrosion of the reaction system was effectively inhibited when phen and NMI were simultaneously used as the ligands. Under the reaction conditions of cCuCl = 0.2 mol/L, nCu:nphen:nNMI = 2:1:1, T = 393 K, P = 2.4 MPa with PCO/PO2 = 2:1, and time = 3 h, conversion of ethanol and selectivity to diethyl carbonate (DEC) were 15.2% and 99.0%, respectively. As compared to pure CuCl, the catalytic activity of CuCl/phen/NMI is much higher (3.6-fold). Furthermore, the high catalytic activity could be kept for a long time of service during the reaction. Corrosion of CuCl was also inhibited by using phen and NMI as ligands. For example, the inhibition efficiencies of CuCl/phen/NMI catalyst system on stainless steel 304 and Hastelloy 5923 were 98.1% and 98.2%, respectively. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901139e [article] CuCl/phen/NMI in homogeneous carbonylation for synthesis of diethyl carbonate : highly active catalyst and corrosion inhibitor [texte imprimé] / Hui Xiong, Auteur ; Wanling Mo, Auteur ; Jianglin Hu, Auteur . - 2010 . - pp. 10845–10849.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10845–10849
Mots-clés : Ethanol CuCl-catalyzed oxidative carbonylation N-donor ligands Résumé : The effects of N-donor ligands on CuCl-catalyzed oxidative carbonylation of ethanol were investigated. It was found that 1,10-phenanthroline (phen) and N-methyl imidazole (NMI) exhibited a synergic effect on the catalytic activity. Catalytic efficiency of the CuCl system was enhanced dramatically, and corrosion of the reaction system was effectively inhibited when phen and NMI were simultaneously used as the ligands. Under the reaction conditions of cCuCl = 0.2 mol/L, nCu:nphen:nNMI = 2:1:1, T = 393 K, P = 2.4 MPa with PCO/PO2 = 2:1, and time = 3 h, conversion of ethanol and selectivity to diethyl carbonate (DEC) were 15.2% and 99.0%, respectively. As compared to pure CuCl, the catalytic activity of CuCl/phen/NMI is much higher (3.6-fold). Furthermore, the high catalytic activity could be kept for a long time of service during the reaction. Corrosion of CuCl was also inhibited by using phen and NMI as ligands. For example, the inhibition efficiencies of CuCl/phen/NMI catalyst system on stainless steel 304 and Hastelloy 5923 were 98.1% and 98.2%, respectively. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901139e Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10850–10856
Titre : Biodiesel production from jatropha curcas, waste cooking, and camelina sativa oils Type de document : texte imprimé Auteurs : Prafulla D. Patil, Auteur ; Veera Gnaneswar Gude, Auteur ; Shuguang Deng, Auteur Année de publication : 2010 Article en page(s) : pp. 10850–10856 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Biodiesel production Jatropha curcas oil Waste cooking Camelina sativa Résumé : Process parameter evaluation and catalyst performance study was conducted for biodiesel production using jatropha curcas, waste cooking, and camelina sativa oils. Conversion of triglycerides to methyl esters involves esterification and/or transesterification, depending on the nature of the feedstock. A two-step transesterification process (acid esterification followed by alkali transesterification) was employed to produce biodiesel from high free fatty acids (FFA) in jatropha curcas and waste cooking oils, and a single-step transesterifcation process (alkali transesterifcation) was used for camelina sativa oil conversion. Catalyst selection is vital in transesterification process because it determines biodiesel yield and cost. Transesterification of jatropha curcas and waste cooking oil was optimized by using H2SO4 and ferric sulfate catalysts in the acid esterification step and a KOH catalyst in the alkali transesterification, respectively. Heterogeneous metal oxide catalysts including BaO, SrO, MgO, and CaO were used for the transesterification of camelina sativa oil.
Jatropha curcas oil was observed to have yields in the range of 90−95%, with a maximum of 95% obtained at the following process conditions: acid esterification, methanol to oil molar ratio of 6:1, 0.5% of H2SO4, and 40 ± 5 °C; alkali tranesterification, methanol to oil molar ratio of 9:1, 2% of KOH, and 60 °C. Waste cooking oil yielded biodiesel in the range of 85−96%, with a maximum of 96% observed at the following optimized process conditions: 2 h reaction at 100 °C, methanol to oil molar ratio of 9:1, and 2% of a ferric sulfate catalyst. Comparative experiments on camelina sativa oil conversion showed that the most effective catalyst was BaO that showed >80% yield of camelina to biodiesel. Fuel properties of biodiesel produced from the three different feedstocks were determined and compared with the ASTM standards for biodiesel and petroleum diesel.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901146c [article] Biodiesel production from jatropha curcas, waste cooking, and camelina sativa oils [texte imprimé] / Prafulla D. Patil, Auteur ; Veera Gnaneswar Gude, Auteur ; Shuguang Deng, Auteur . - 2010 . - pp. 10850–10856.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10850–10856
Mots-clés : Biodiesel production Jatropha curcas oil Waste cooking Camelina sativa Résumé : Process parameter evaluation and catalyst performance study was conducted for biodiesel production using jatropha curcas, waste cooking, and camelina sativa oils. Conversion of triglycerides to methyl esters involves esterification and/or transesterification, depending on the nature of the feedstock. A two-step transesterification process (acid esterification followed by alkali transesterification) was employed to produce biodiesel from high free fatty acids (FFA) in jatropha curcas and waste cooking oils, and a single-step transesterifcation process (alkali transesterifcation) was used for camelina sativa oil conversion. Catalyst selection is vital in transesterification process because it determines biodiesel yield and cost. Transesterification of jatropha curcas and waste cooking oil was optimized by using H2SO4 and ferric sulfate catalysts in the acid esterification step and a KOH catalyst in the alkali transesterification, respectively. Heterogeneous metal oxide catalysts including BaO, SrO, MgO, and CaO were used for the transesterification of camelina sativa oil.
Jatropha curcas oil was observed to have yields in the range of 90−95%, with a maximum of 95% obtained at the following process conditions: acid esterification, methanol to oil molar ratio of 6:1, 0.5% of H2SO4, and 40 ± 5 °C; alkali tranesterification, methanol to oil molar ratio of 9:1, 2% of KOH, and 60 °C. Waste cooking oil yielded biodiesel in the range of 85−96%, with a maximum of 96% observed at the following optimized process conditions: 2 h reaction at 100 °C, methanol to oil molar ratio of 9:1, and 2% of a ferric sulfate catalyst. Comparative experiments on camelina sativa oil conversion showed that the most effective catalyst was BaO that showed >80% yield of camelina to biodiesel. Fuel properties of biodiesel produced from the three different feedstocks were determined and compared with the ASTM standards for biodiesel and petroleum diesel.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901146c Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10857–10863
Titre : Simultaneous hydrogenation and isomerization of diisobutylenes over pd-doped ion-exchange resin catalyst Type de document : texte imprimé Auteurs : Sandip Talwalkar, Auteur ; Suman Thotla, Auteur ; Kai Sundmacher, Auteur Année de publication : 2010 Article en page(s) : pp. 10857–10863 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Bifunctional ion-exchange-resin catalyst Diisobutylene Hydrogenation Isomerization Résumé : The present work evaluates the applicability of a bifunctional ion-exchange-resin catalyst for the effective hydrogenation of diisobutylene, which is generally available as an equilibrium mixture of its isomers, mainly 2,4,4-trimethylpent-1-ene and 2,4,4-trimethylpent-2-ene. The terminal double bond in 2,4,4-trimethylpent-1-ene gets hydrogenated substantially more quickly than the relatively stable internal double bond in 2,4,4-trimethylpent-2-ene under relatively mild reaction conditions. Therefore, there is a need for a catalyst that is active for hydrogenation as well as simultaneous isomerization of 2,4,4-trimethylpent-2-ene to 2,4,4-trimethylpent-1-ene under mild reaction conditions. The present catalyst was found to be capable of performing simultaneous hydrogenation and isomerization, thereby increasing the reaction rate. The effects of various operating parameters were studied, and a kinetic model is proposed to explain the observed reaction rates. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9012419 [article] Simultaneous hydrogenation and isomerization of diisobutylenes over pd-doped ion-exchange resin catalyst [texte imprimé] / Sandip Talwalkar, Auteur ; Suman Thotla, Auteur ; Kai Sundmacher, Auteur . - 2010 . - pp. 10857–10863.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10857–10863
Mots-clés : Bifunctional ion-exchange-resin catalyst Diisobutylene Hydrogenation Isomerization Résumé : The present work evaluates the applicability of a bifunctional ion-exchange-resin catalyst for the effective hydrogenation of diisobutylene, which is generally available as an equilibrium mixture of its isomers, mainly 2,4,4-trimethylpent-1-ene and 2,4,4-trimethylpent-2-ene. The terminal double bond in 2,4,4-trimethylpent-1-ene gets hydrogenated substantially more quickly than the relatively stable internal double bond in 2,4,4-trimethylpent-2-ene under relatively mild reaction conditions. Therefore, there is a need for a catalyst that is active for hydrogenation as well as simultaneous isomerization of 2,4,4-trimethylpent-2-ene to 2,4,4-trimethylpent-1-ene under mild reaction conditions. The present catalyst was found to be capable of performing simultaneous hydrogenation and isomerization, thereby increasing the reaction rate. The effects of various operating parameters were studied, and a kinetic model is proposed to explain the observed reaction rates. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9012419 Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10864–10869
Titre : Effects of varying the preparation conditions on the dielectric constant of mixed metal oxide films derived from layered double hydroxide precursor films Type de document : texte imprimé Auteurs : Xiaoxiao Guo, Auteur ; Fazhi Zhang, Auteur ; Sailong Xu, Auteur Année de publication : 2010 Article en page(s) : pp. 10864–10869 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Layered double hydroxide films Scanning electron microscopy images Résumé : Magnesium/aluminum layered double hydroxide (LDH) films have been prepared in situ by means of urea hydrolysis using aluminum metal as both the substrate and sole source of aluminum. Scanning electron microscopy (SEM) images showed that the LDH crystallites are almost perpendicular to the substrate and interlaced with each other forming a network of vacant pockets. The film showed outstanding mechanical strength and high adhesion with the substrate. After being calcined at 500 °C, MgAl mixed metal oxide (MMO) films were obtained which retained the morphology of the precursor films. The values of dielectric constant (k) of the MgAl-MMO films were measured and showed low values in the range 2.0−4.7 arising from the low density of the interlaced structure. The effect of varying the preparation conditions of the LDH precursor films on the microstructure and k-value of the corresponding MMO films was investigated by varying the metal ion concentration, crystallization time, and crystallization temperature. The MMO films became more compact with increasing metal ion concentration and crystallization time, which resulted in increased k-values. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900671b [article] Effects of varying the preparation conditions on the dielectric constant of mixed metal oxide films derived from layered double hydroxide precursor films [texte imprimé] / Xiaoxiao Guo, Auteur ; Fazhi Zhang, Auteur ; Sailong Xu, Auteur . - 2010 . - pp. 10864–10869.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10864–10869
Mots-clés : Layered double hydroxide films Scanning electron microscopy images Résumé : Magnesium/aluminum layered double hydroxide (LDH) films have been prepared in situ by means of urea hydrolysis using aluminum metal as both the substrate and sole source of aluminum. Scanning electron microscopy (SEM) images showed that the LDH crystallites are almost perpendicular to the substrate and interlaced with each other forming a network of vacant pockets. The film showed outstanding mechanical strength and high adhesion with the substrate. After being calcined at 500 °C, MgAl mixed metal oxide (MMO) films were obtained which retained the morphology of the precursor films. The values of dielectric constant (k) of the MgAl-MMO films were measured and showed low values in the range 2.0−4.7 arising from the low density of the interlaced structure. The effect of varying the preparation conditions of the LDH precursor films on the microstructure and k-value of the corresponding MMO films was investigated by varying the metal ion concentration, crystallization time, and crystallization temperature. The MMO films became more compact with increasing metal ion concentration and crystallization time, which resulted in increased k-values. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900671b Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10870–10876
Titre : Crystal structure of tubular Na-LTA zeolite membrane used for a vapor permeation process : unusual distribution of adsorbed water molecules Type de document : texte imprimé Auteurs : Tomohiro Kyotani, Auteur ; Takuji Ikeda, Auteur ; Junji Saito, Auteur Année de publication : 2010 Article en page(s) : pp. 10870–10876 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Tubular zeolite Na− LTA membranes Bioethanol Vapor permeation processes Résumé : The crystal structure of two tubular zeolite Na−LTA membranes—one as-prepared membrane and a membrane used in vapor permeation (VP) processes of bioethanol—was analyzed using Rietveld refinement with parallel-beam powder X-ray diffraction data. The crystal structure of the as-prepared membrane was consistent with that of typical Na−LTA powder. After the VP process, an unusual relative peak intensity ratio between 200 and 220 reflections was observed in the membrane. The number of adsorbed water molecules in the β-cage was reduced to half. Furthermore, detachment of sodium cations at the six-membered rings was confirmed. The electron density distributions of these Na−LTA zeolite membranes were analyzed by combining the Rietveld method and the maximum entropy method (MEM). MEM electron density images revealed that the adsorbed water molecules and Na+ cations were bonded, forming a hydrated cluster, and that the guest atoms or molecules were highly disordered. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900967e [article] Crystal structure of tubular Na-LTA zeolite membrane used for a vapor permeation process : unusual distribution of adsorbed water molecules [texte imprimé] / Tomohiro Kyotani, Auteur ; Takuji Ikeda, Auteur ; Junji Saito, Auteur . - 2010 . - pp. 10870–10876.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10870–10876
Mots-clés : Tubular zeolite Na− LTA membranes Bioethanol Vapor permeation processes Résumé : The crystal structure of two tubular zeolite Na−LTA membranes—one as-prepared membrane and a membrane used in vapor permeation (VP) processes of bioethanol—was analyzed using Rietveld refinement with parallel-beam powder X-ray diffraction data. The crystal structure of the as-prepared membrane was consistent with that of typical Na−LTA powder. After the VP process, an unusual relative peak intensity ratio between 200 and 220 reflections was observed in the membrane. The number of adsorbed water molecules in the β-cage was reduced to half. Furthermore, detachment of sodium cations at the six-membered rings was confirmed. The electron density distributions of these Na−LTA zeolite membranes were analyzed by combining the Rietveld method and the maximum entropy method (MEM). MEM electron density images revealed that the adsorbed water molecules and Na+ cations were bonded, forming a hydrated cluster, and that the guest atoms or molecules were highly disordered. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900967e Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10877–10883
Titre : Gypsum scale control by nitrilotrimethylenephosphonic acid Type de document : texte imprimé Auteurs : Marina Prisciandaro, Auteur ; Emilia Olivieri, Auteur ; Amedeo Lancia, Auteur Année de publication : 2010 Article en page(s) : pp. 10877–10883 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Nitrilotrimethylenephosphonic acid Calcium sulfate dihydrate nucleation kinetics Résumé : In this paper the retardant effect of nitrilotrimethylenephosphonic acid (NTMP) on calcium sulfate dihydrate nucleation kinetics is evaluated by means of an optical technique able to accurately measure the induction period. A laboratory-scale experimental apparatus is used, in which sodium sulfate and calcium chloride are mixed to obtain a supersaturated calcium sulfate dihydrate solution; all experiments are carried out for various values of NTMP concentrations (0.005−0.05 g/L) in solution, while changing the saturation index in the range of 4.04 − 4.82; the temperature was varied in the interval 15−45 °C. Experimentally measured induction times are used to evaluate the interfacial tension (γS) between crystals and mother solution and to estimate the activation energy (Eatt) for precipitation in the presence of NTMP. The measured values of γS and Eatt are compared with those found in the absence of any additive and in the presence of citric acid, showing that NTMP is a very strong retardant for gypsum nucleation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900253f [article] Gypsum scale control by nitrilotrimethylenephosphonic acid [texte imprimé] / Marina Prisciandaro, Auteur ; Emilia Olivieri, Auteur ; Amedeo Lancia, Auteur . - 2010 . - pp. 10877–10883.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10877–10883
Mots-clés : Nitrilotrimethylenephosphonic acid Calcium sulfate dihydrate nucleation kinetics Résumé : In this paper the retardant effect of nitrilotrimethylenephosphonic acid (NTMP) on calcium sulfate dihydrate nucleation kinetics is evaluated by means of an optical technique able to accurately measure the induction period. A laboratory-scale experimental apparatus is used, in which sodium sulfate and calcium chloride are mixed to obtain a supersaturated calcium sulfate dihydrate solution; all experiments are carried out for various values of NTMP concentrations (0.005−0.05 g/L) in solution, while changing the saturation index in the range of 4.04 − 4.82; the temperature was varied in the interval 15−45 °C. Experimentally measured induction times are used to evaluate the interfacial tension (γS) between crystals and mother solution and to estimate the activation energy (Eatt) for precipitation in the presence of NTMP. The measured values of γS and Eatt are compared with those found in the absence of any additive and in the presence of citric acid, showing that NTMP is a very strong retardant for gypsum nucleation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900253f Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10884–10891
Titre : Adsorption/reduction of NO2 on graphite oxide/Iron composites Type de document : texte imprimé Auteurs : Svetlana Bashkova, Auteur ; Teresa J. Bandosz, Auteur Année de publication : 2010 Article en page(s) : pp. 10884–10891 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Adsorption of NO2 Retention NO Graphite oxide X-ray diffraction Scanning electron microscopy Fourier transform infrared Thermogravimetric analysis Résumé : Adsorption of NO2 and the retention of NO (the product of NO2 reduction by carbon) on the materials prepared from iron acetato complex and its mixture with graphite oxide were studied. The surface of the materials was characterized using adsorption of nitrogen, X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and thermogravimetric analysis (TGA). The results showed that the development of texture and porosity along with formation of some active surface species on the graphite oxide/iron composite materials leads to an increase in NO2 adsorption. An immediate reduction of NO2 to NO by carbon was noticed for all samples except for the one that contained a smallest amount of carbon in a mostly oxidized form. The retention of NO on the surface of the materials does not depend on their structural characteristics. Better performance is found for the materials that contain active iron species, such as γ-FeOOH and α-Fe2O3, which likely react with NO molecules forming surface nitrates. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901054p [article] Adsorption/reduction of NO2 on graphite oxide/Iron composites [texte imprimé] / Svetlana Bashkova, Auteur ; Teresa J. Bandosz, Auteur . - 2010 . - pp. 10884–10891.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10884–10891
Mots-clés : Adsorption of NO2 Retention NO Graphite oxide X-ray diffraction Scanning electron microscopy Fourier transform infrared Thermogravimetric analysis Résumé : Adsorption of NO2 and the retention of NO (the product of NO2 reduction by carbon) on the materials prepared from iron acetato complex and its mixture with graphite oxide were studied. The surface of the materials was characterized using adsorption of nitrogen, X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and thermogravimetric analysis (TGA). The results showed that the development of texture and porosity along with formation of some active surface species on the graphite oxide/iron composite materials leads to an increase in NO2 adsorption. An immediate reduction of NO2 to NO by carbon was noticed for all samples except for the one that contained a smallest amount of carbon in a mostly oxidized form. The retention of NO on the surface of the materials does not depend on their structural characteristics. Better performance is found for the materials that contain active iron species, such as γ-FeOOH and α-Fe2O3, which likely react with NO molecules forming surface nitrates. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901054p Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10892–10902
Titre : Consistent inventory control Type de document : texte imprimé Auteurs : Elvira Marie B. Aske, Auteur ; Sigurd Skogestad, Auteur Année de publication : 2010 Article en page(s) : pp. 10892–10902 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Material balance control Résumé : Inventory or material balance control is an important part of process control. In the literature, many rules have been proposed to help in designing such systems, but their justification is often unclear. The main contribution of this paper is to propose the more general local-consistency rule for evaluating inventory control systems. Consistency means that the steady-state mass balances (total, component, and phase) for the individual units and the overall plant are satisfied. In addition, local consistency is a desired property, meaning that the local mass balances are satisfied with local inventory loops only. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801603j [article] Consistent inventory control [texte imprimé] / Elvira Marie B. Aske, Auteur ; Sigurd Skogestad, Auteur . - 2010 . - pp. 10892–10902.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10892–10902
Mots-clés : Material balance control Résumé : Inventory or material balance control is an important part of process control. In the literature, many rules have been proposed to help in designing such systems, but their justification is often unclear. The main contribution of this paper is to propose the more general local-consistency rule for evaluating inventory control systems. Consistency means that the steady-state mass balances (total, component, and phase) for the individual units and the overall plant are satisfied. In addition, local consistency is a desired property, meaning that the local mass balances are satisfied with local inventory loops only. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801603j Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10903–10911
Titre : Support vector regression approach for simultaneous data reconciliation and gross error or outlier detection Type de document : texte imprimé Auteurs : Yu Miao, Auteur ; Hongye Su, Auteur ; Ouguan Xu, Auteur Année de publication : 2010 Article en page(s) : pp. 10903–10911 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Support vector regression Outlier detection Résumé : Process data measurements are important for model fitting, process monitoring, control, optimization, and management decision making, and they are usually applied with parameter estimation. This paper applies the support vector (SV) regression approach as a framework for simultaneous data reconciliation and gross error or outlier detection in processes. SV regression minimizes regularized risk instead of maximum likelihood, and it is a compromise between empirical risk and model complexity. For data reconciliation, it is robust to random and gross errors or outliers, because loss functions are addressed as objective functions instead of least-squares. Furthermore, because of the robust nature of SV regressions, the coefficients of the SV regression itself have less effect on the reconciled results. Finally, a number of process and literature system simulation results show the features of the SV regression approach for data reconciliation proposed in this paper. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801629f [article] Support vector regression approach for simultaneous data reconciliation and gross error or outlier detection [texte imprimé] / Yu Miao, Auteur ; Hongye Su, Auteur ; Ouguan Xu, Auteur . - 2010 . - pp. 10903–10911.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10903–10911
Mots-clés : Support vector regression Outlier detection Résumé : Process data measurements are important for model fitting, process monitoring, control, optimization, and management decision making, and they are usually applied with parameter estimation. This paper applies the support vector (SV) regression approach as a framework for simultaneous data reconciliation and gross error or outlier detection in processes. SV regression minimizes regularized risk instead of maximum likelihood, and it is a compromise between empirical risk and model complexity. For data reconciliation, it is robust to random and gross errors or outliers, because loss functions are addressed as objective functions instead of least-squares. Furthermore, because of the robust nature of SV regressions, the coefficients of the SV regression itself have less effect on the reconciled results. Finally, a number of process and literature system simulation results show the features of the SV regression approach for data reconciliation proposed in this paper. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801629f Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10912–10923
Titre : Online probabilistic assessment of operating performance based on safety and optimality indices for multimode industrial processes Type de document : texte imprimé Auteurs : Lubin Ye, Auteur ; Yuming Liu, Auteur ; Zhengshun Fei, Auteur Année de publication : 2010 Article en page(s) : pp. 10912–10923 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Online operating assessment Probabilistic framework Gaussian mixture model Résumé : Operating performance of industrial process on safety and optimality may deteriorate with time due to process characteristic variation, and it is crucial to develop strategies for online operating performance assessment. Although there have been some studies and applications on process safety assessment, optimality assessment has not yet been paid sufficient attention. This paper proposes a probabilistic framework of online operating assessment for industrial processes. First, a Gaussian mixture model (GMM) is used to characterize multiple operating modes. Considering the distribution of process variables, safety and optimality indices (SI and OI) are defined and calculated by two successive nonlinear mappings. A hierarchical-level classification method is then presented to divide these indices into different performance levels, and margin analysis on each level is introduced. Finally, performance prediction and preliminary suggestions for improvement are provided. The proposed assessment strategy is then applied in two examples: Tennessee Eastman Process (TEP) and polypropylene (PP) production process, which indicate the efficiency of the proposed approach. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801870g [article] Online probabilistic assessment of operating performance based on safety and optimality indices for multimode industrial processes [texte imprimé] / Lubin Ye, Auteur ; Yuming Liu, Auteur ; Zhengshun Fei, Auteur . - 2010 . - pp. 10912–10923.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10912–10923
Mots-clés : Online operating assessment Probabilistic framework Gaussian mixture model Résumé : Operating performance of industrial process on safety and optimality may deteriorate with time due to process characteristic variation, and it is crucial to develop strategies for online operating performance assessment. Although there have been some studies and applications on process safety assessment, optimality assessment has not yet been paid sufficient attention. This paper proposes a probabilistic framework of online operating assessment for industrial processes. First, a Gaussian mixture model (GMM) is used to characterize multiple operating modes. Considering the distribution of process variables, safety and optimality indices (SI and OI) are defined and calculated by two successive nonlinear mappings. A hierarchical-level classification method is then presented to divide these indices into different performance levels, and margin analysis on each level is introduced. Finally, performance prediction and preliminary suggestions for improvement are provided. The proposed assessment strategy is then applied in two examples: Tennessee Eastman Process (TEP) and polypropylene (PP) production process, which indicate the efficiency of the proposed approach. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801870g Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10924–10940
Titre : Optimal design of an integrated discontinuous water-using network coordinating with a central continuous regeneration unit Type de document : texte imprimé Auteurs : Yongzhong Liu, Auteur ; Guanhua Li, Auteur ; Le Wang, Auteur Année de publication : 2010 Article en page(s) : pp. 10924–10940 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Water Regeneration unit Résumé : A systematic approach is proposed to design an optimal batch water-using network with centralized regeneration in order to deal with coordination of discontinuous water-using operations with one central continuous regeneration unit during multiple repeated batch cycles. The mathematical formulation in weak forms that readily induces process dynamic expressions is established under the framework of continuous time representation, in which a rigorous dynamic model of a tank is embedded. The freshwater consumption and the regeneration flow rates are minimized by a two-stage optimization approach. The integration of the batch water-using system highlights fixed regeneration flow rates and transitional behaviors from the start-up phase to steady state in multiple batch cycles. Optimal network structures and evolution characteristics of residual water and contaminant concentrations in buffer tanks can be achieved through solutions to the nonlinear programming problems (NLP). Four scenarios, including truly batch and semicontinuous water-using systems in both multiproduct and multipurpose batch plants, are presented to demonstrate the applicability of the proposed approach. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9000053 [article] Optimal design of an integrated discontinuous water-using network coordinating with a central continuous regeneration unit [texte imprimé] / Yongzhong Liu, Auteur ; Guanhua Li, Auteur ; Le Wang, Auteur . - 2010 . - pp. 10924–10940.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10924–10940
Mots-clés : Water Regeneration unit Résumé : A systematic approach is proposed to design an optimal batch water-using network with centralized regeneration in order to deal with coordination of discontinuous water-using operations with one central continuous regeneration unit during multiple repeated batch cycles. The mathematical formulation in weak forms that readily induces process dynamic expressions is established under the framework of continuous time representation, in which a rigorous dynamic model of a tank is embedded. The freshwater consumption and the regeneration flow rates are minimized by a two-stage optimization approach. The integration of the batch water-using system highlights fixed regeneration flow rates and transitional behaviors from the start-up phase to steady state in multiple batch cycles. Optimal network structures and evolution characteristics of residual water and contaminant concentrations in buffer tanks can be achieved through solutions to the nonlinear programming problems (NLP). Four scenarios, including truly batch and semicontinuous water-using systems in both multiproduct and multipurpose batch plants, are presented to demonstrate the applicability of the proposed approach. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9000053 Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10941–10961
Titre : Application and evaluation of three methodologies for plantwide control of the styrene monomer plant Type de document : texte imprimé Auteurs : Suraj Vasudevan, Auteur ; G.P. Rangaiah, Auteur ; N. V. S. N. Murthy Konda, Auteur Année de publication : 2010 Article en page(s) : pp. 10941–10961 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Plantwide control methodologies Styrene monomer plant Résumé : Plantwide control (PWC) methodologies have gained significant importance given the high and increasing degree of integration in chemical processes due to material recycle, energy integration, and stringent product quality control, all of which though economically favorable, pose tough challenges to smooth plant operation. As part of the continuing search for more effective PWC system design methods, an integrated framework of heuristics and simulation was proposed [Konda et al. Ind. Eng. Chem. Res. 2005, 44, 8300−8313]. The basic idea behind this development is to make effective use of rigorous process simulators to aid in decision-making during the development of the heuristic-based PWC structure. Konda and co-workers have successfully applied the procedure to the toluene hydrodealkylation process. Though the integrated framework is promising, there is still a need to test its applicability to other complex industrial processes. The present contribution considers the development of a PWC structure for the styrene monomer plant using the integrated framework. In addition, in order to gauge its effectiveness in comparison to the other plantwide control methods, two more methods are considered in this study. First, the heuristics procedure of Luyben and co-workers [Luyben et al. Plant-Wide Process Control; McGraw-Hill: New York, 1998], which is a popular heuristics-based methodology, is also applied to the same flowsheet, and is considered as the base case for performance assessment. Second, the self-optimizing control procedure [Skogestad, S. Comput. Chem. Eng. 2004, 28, 219−234] is also used in order to have a more comprehensive analysis of the effectiveness of the integrated framework. An analysis of the results indicates that while all the procedures give stable control structures, the integrated framework and self-optimizing control procedures give more robust control structures than the heuristics procedure. This is the first study to develop simulation models and complete PWC structures for the styrene plant, together with a detailed analysis of the relative performance of the resulting structures in order to evaluate the different PWC methodologies. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900022h [article] Application and evaluation of three methodologies for plantwide control of the styrene monomer plant [texte imprimé] / Suraj Vasudevan, Auteur ; G.P. Rangaiah, Auteur ; N. V. S. N. Murthy Konda, Auteur . - 2010 . - pp. 10941–10961.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10941–10961
Mots-clés : Plantwide control methodologies Styrene monomer plant Résumé : Plantwide control (PWC) methodologies have gained significant importance given the high and increasing degree of integration in chemical processes due to material recycle, energy integration, and stringent product quality control, all of which though economically favorable, pose tough challenges to smooth plant operation. As part of the continuing search for more effective PWC system design methods, an integrated framework of heuristics and simulation was proposed [Konda et al. Ind. Eng. Chem. Res. 2005, 44, 8300−8313]. The basic idea behind this development is to make effective use of rigorous process simulators to aid in decision-making during the development of the heuristic-based PWC structure. Konda and co-workers have successfully applied the procedure to the toluene hydrodealkylation process. Though the integrated framework is promising, there is still a need to test its applicability to other complex industrial processes. The present contribution considers the development of a PWC structure for the styrene monomer plant using the integrated framework. In addition, in order to gauge its effectiveness in comparison to the other plantwide control methods, two more methods are considered in this study. First, the heuristics procedure of Luyben and co-workers [Luyben et al. Plant-Wide Process Control; McGraw-Hill: New York, 1998], which is a popular heuristics-based methodology, is also applied to the same flowsheet, and is considered as the base case for performance assessment. Second, the self-optimizing control procedure [Skogestad, S. Comput. Chem. Eng. 2004, 28, 219−234] is also used in order to have a more comprehensive analysis of the effectiveness of the integrated framework. An analysis of the results indicates that while all the procedures give stable control structures, the integrated framework and self-optimizing control procedures give more robust control structures than the heuristics procedure. This is the first study to develop simulation models and complete PWC structures for the styrene plant, together with a detailed analysis of the relative performance of the resulting structures in order to evaluate the different PWC methodologies. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900022h Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10962–10975
Titre : Conceptual analysis of the effect of kinetics on the stability and multiplicity of a coupled bioreactor−separator system using a cybernetic modeling approach Type de document : texte imprimé Auteurs : M. Vasudeva Kumar, Auteur ; K. P. Zeyer, Auteur ; A. Kienle, Auteur Année de publication : 2010 Article en page(s) : pp. 10962–10975 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Bioreactor− separator system Kinetics Cybernetic modeling approach Résumé : In this work, the nonlinear behavior of a bioreactor coupled to a separator is analyzed. The main focus is on the effect of kinetics on the stability and multiplicity of the coupled system using a cybernetic modeling approach. One example of such a system is the activated sludge process. In this work we consider the growth of a culture of Pseudomonas putida in a medium containing phenol and glucose. We propose a cybernetic model which accounts for the regulatory features in the microorganism in a qualitative way in the aerator. These regulatory features control the rate of uptake of the substrates by the cells in the aerator. We use kinetics with self-substrate inhibition and cross-substrate inhibition effects. We observe a strong dependence of the window of multiplicity on kinetics. We depict that introduction of the more detailed kinetics into the model considerably widens the multiplicity region and helps the experimentalist to design the experiments. We use flocculation kinetics in the bioreactor which is the key for the settling of the suspended solids. The more realistic limiting flux condition is also introduced in the settler. We depict that under such conditions the resulting model of the coupled system exhibits nongrowth associated maintenance phenomena which occur at low dilution rates. The model equations governing the system behavior are ordinary differential equations and algebraic equations. In this work we vary the dilution rate and study the behavior of the system. We observe a shift in the uptake rates of the substrates as we vary the dilution rate. A two parameter continuation is also carried out to investigate the effect of other operating parameters on the nonlinear behavior. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900140u [article] Conceptual analysis of the effect of kinetics on the stability and multiplicity of a coupled bioreactor−separator system using a cybernetic modeling approach [texte imprimé] / M. Vasudeva Kumar, Auteur ; K. P. Zeyer, Auteur ; A. Kienle, Auteur . - 2010 . - pp. 10962–10975.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10962–10975
Mots-clés : Bioreactor− separator system Kinetics Cybernetic modeling approach Résumé : In this work, the nonlinear behavior of a bioreactor coupled to a separator is analyzed. The main focus is on the effect of kinetics on the stability and multiplicity of the coupled system using a cybernetic modeling approach. One example of such a system is the activated sludge process. In this work we consider the growth of a culture of Pseudomonas putida in a medium containing phenol and glucose. We propose a cybernetic model which accounts for the regulatory features in the microorganism in a qualitative way in the aerator. These regulatory features control the rate of uptake of the substrates by the cells in the aerator. We use kinetics with self-substrate inhibition and cross-substrate inhibition effects. We observe a strong dependence of the window of multiplicity on kinetics. We depict that introduction of the more detailed kinetics into the model considerably widens the multiplicity region and helps the experimentalist to design the experiments. We use flocculation kinetics in the bioreactor which is the key for the settling of the suspended solids. The more realistic limiting flux condition is also introduced in the settler. We depict that under such conditions the resulting model of the coupled system exhibits nongrowth associated maintenance phenomena which occur at low dilution rates. The model equations governing the system behavior are ordinary differential equations and algebraic equations. In this work we vary the dilution rate and study the behavior of the system. We observe a shift in the uptake rates of the substrates as we vary the dilution rate. A two parameter continuation is also carried out to investigate the effect of other operating parameters on the nonlinear behavior. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900140u Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10976–10985
Titre : Exergy analysis of the process for dimethyl ether production through biomass steam gasification Type de document : texte imprimé Auteurs : Xiangping Zhang, Auteur ; Christian Solli, Auteur ; Edgar G. Hertwich, Auteur Année de publication : 2010 Article en page(s) : pp. 10976–10985 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Biomass steam gasification to fuel Quasi-equilibrium model Résumé : A flowsheet for the production of the substitutable transportation fuel dimethyl ether through biomass steam gasification to fuel (BSGtF) was constructed including heat integration. A quasi-equilibrium model was applied to simulate the whole process based on rigorous thermodynamic property prediction models. The carbon and hydrogen flows of the process showed that the atom utilization efficiency of carbon from the biomass to fuel process was 38.47%, and 39.75% of the total hydrogen was converted to the fuel product. The exergy flows of the total process and the exergy loss taking place in each process section were calculated based on the second law of thermodynamics. The results indicated that the total energy and exergy efficiencies from biomass to fuel were 51.3% and 43.5%, respectively, with a negative CO2 emission effect. The effects of gasification temperature, combustion temperature, and steam/biomass ratio on the gasification performance were investigated. The causes of exergy losses were analyzed to identify the areas of improvement so that a high energy utilization efficiency could be achieved. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900199e [article] Exergy analysis of the process for dimethyl ether production through biomass steam gasification [texte imprimé] / Xiangping Zhang, Auteur ; Christian Solli, Auteur ; Edgar G. Hertwich, Auteur . - 2010 . - pp. 10976–10985.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10976–10985
Mots-clés : Biomass steam gasification to fuel Quasi-equilibrium model Résumé : A flowsheet for the production of the substitutable transportation fuel dimethyl ether through biomass steam gasification to fuel (BSGtF) was constructed including heat integration. A quasi-equilibrium model was applied to simulate the whole process based on rigorous thermodynamic property prediction models. The carbon and hydrogen flows of the process showed that the atom utilization efficiency of carbon from the biomass to fuel process was 38.47%, and 39.75% of the total hydrogen was converted to the fuel product. The exergy flows of the total process and the exergy loss taking place in each process section were calculated based on the second law of thermodynamics. The results indicated that the total energy and exergy efficiencies from biomass to fuel were 51.3% and 43.5%, respectively, with a negative CO2 emission effect. The effects of gasification temperature, combustion temperature, and steam/biomass ratio on the gasification performance were investigated. The causes of exergy losses were analyzed to identify the areas of improvement so that a high energy utilization efficiency could be achieved. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900199e Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10986–10993
Titre : Observer-controller design for a class of stable/unstable inverse pesponse processes Type de document : texte imprimé Auteurs : Carles Pedret, Auteur ; Salva Alcántara, Auteur ; Ramon Vilanova, Auteur Année de publication : 2010 Article en page(s) : pp. 10986–10993 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Two-degree-of-freedom configuration Smith-type predictor Résumé : This paper proposes the use of a two-degree-of-freedom configuration aimed at the control of inverse response processes. An observer−controller scheme based on coprime factorization results in a Smith-type predictor well suited for both stable and unstable inverse response processes. The design procedure is carried in two steps. First, the controller is designed providing an adjustable parameter to cope with the reference input tracking. Second, the observer blocks are selected for closed-loop properties, offering another tuning parameter to compromise between robust stability and disturbance rejection performance. As a result, the nominal set point response is decoupled from the disturbance response. To show the applicability of the proposed control configuration, its performance is compared by simulation with different approaches. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9002377 [article] Observer-controller design for a class of stable/unstable inverse pesponse processes [texte imprimé] / Carles Pedret, Auteur ; Salva Alcántara, Auteur ; Ramon Vilanova, Auteur . - 2010 . - pp. 10986–10993.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10986–10993
Mots-clés : Two-degree-of-freedom configuration Smith-type predictor Résumé : This paper proposes the use of a two-degree-of-freedom configuration aimed at the control of inverse response processes. An observer−controller scheme based on coprime factorization results in a Smith-type predictor well suited for both stable and unstable inverse response processes. The design procedure is carried in two steps. First, the controller is designed providing an adjustable parameter to cope with the reference input tracking. Second, the observer blocks are selected for closed-loop properties, offering another tuning parameter to compromise between robust stability and disturbance rejection performance. As a result, the nominal set point response is decoupled from the disturbance response. To show the applicability of the proposed control configuration, its performance is compared by simulation with different approaches. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9002377 Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10994–11001
Titre : Development and implementation of numerical simulation for a selective noncatalytic reduction system design Type de document : texte imprimé Auteurs : Wei Zhou, Auteur ; David Moyeda, Auteur ; Vitali Lissianski, Auteur Année de publication : 2010 Article en page(s) : pp. 10994–11001 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Selective noncatalytic reduction technology Numerical simulation Résumé : Selective noncatalytic reduction (SNCR) technology is an effective and economical method of reducing NOx emissions from a wide range of industrial combustion systems. It is widely known that the SNCR process is primarily effective in a narrow temperature window, around 1200−1255 K, and that high CO concentrations can both shift the temperature window and limit the process’ effectiveness. To ensure proper design and application of SNCR technology, it is critical to understand the flow and temperature fields, SNCR kinetics, and species concentrations in the combustion system and to design an injection system that provides good mixing and distribution of the reagent with the furnace gases. The work summarized in this article developed and incorporated a reduced SNCR chemical mechanism into a commercial computational fluid dynamics (CFD) model. Three main results are reported: (1) the reduced mechanism is validated by comparisons to a detailed mechanism using a plug-flow reactor and a perfectly stirred reactor, (2) the SNCR modeling approach with the reduced mechanism is validated by comparing the three-dimensional modeling results with test data from a pilot-scale combustion furnace, and (3) the integrated CFD modeling approach is applied to designing an SNCR system for an industrial furnace. The SNCR system was installed and has been in operation for several years. The NOx reduction and ammonia slip performance for the full-scale system agreed well with the CFD predictions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9004089 [article] Development and implementation of numerical simulation for a selective noncatalytic reduction system design [texte imprimé] / Wei Zhou, Auteur ; David Moyeda, Auteur ; Vitali Lissianski, Auteur . - 2010 . - pp. 10994–11001.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10994–11001
Mots-clés : Selective noncatalytic reduction technology Numerical simulation Résumé : Selective noncatalytic reduction (SNCR) technology is an effective and economical method of reducing NOx emissions from a wide range of industrial combustion systems. It is widely known that the SNCR process is primarily effective in a narrow temperature window, around 1200−1255 K, and that high CO concentrations can both shift the temperature window and limit the process’ effectiveness. To ensure proper design and application of SNCR technology, it is critical to understand the flow and temperature fields, SNCR kinetics, and species concentrations in the combustion system and to design an injection system that provides good mixing and distribution of the reagent with the furnace gases. The work summarized in this article developed and incorporated a reduced SNCR chemical mechanism into a commercial computational fluid dynamics (CFD) model. Three main results are reported: (1) the reduced mechanism is validated by comparisons to a detailed mechanism using a plug-flow reactor and a perfectly stirred reactor, (2) the SNCR modeling approach with the reduced mechanism is validated by comparing the three-dimensional modeling results with test data from a pilot-scale combustion furnace, and (3) the integrated CFD modeling approach is applied to designing an SNCR system for an industrial furnace. The SNCR system was installed and has been in operation for several years. The NOx reduction and ammonia slip performance for the full-scale system agreed well with the CFD predictions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9004089 Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11002–11016
Titre : Optimal short-term scheduling of large-scale multistage batch plants Type de document : texte imprimé Auteurs : Pedro M. Castro, Auteur ; Iiro Harjunkoski, Auteur ; Ignacio E. Grossmann, Auteur Année de publication : 2010 Article en page(s) : pp. 11002–11016 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Large-scale multiproduct plants Optimal scheduling Decomposition algorithm Résumé : This paper presents a new decomposition algorithm for the optimal scheduling of large-scale multiproduct plants containing a large number of orders. Rather than tackling highly complex, full-space problems that cannot be solved in reasonable time, the complete set of orders is scheduled sequentially by considering one, or a couple of them, at a time. As we proceed through the iterations, previously scheduled orders can be partly rescheduled to allow for some flexibility while keeping the combinatorial complexity at a manageable level. Once a complete schedule is obtained, the same concept is applied to improve the schedule locally. The user can choose to rely on either a unit-specific or a sequencing variable based continuous-time mixed-integer linear programming model. In addition, there are other parameters that affect how the decomposition is carried out, so the algorithm is highly versatile and adaptable to problems of varying sizes. The largest problem solved is a real-life, 50-order, 17-unit, 6-stage problem, for which a very good solution can be found in less than 1 min of computational time. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900734x [article] Optimal short-term scheduling of large-scale multistage batch plants [texte imprimé] / Pedro M. Castro, Auteur ; Iiro Harjunkoski, Auteur ; Ignacio E. Grossmann, Auteur . - 2010 . - pp. 11002–11016.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11002–11016
Mots-clés : Large-scale multiproduct plants Optimal scheduling Decomposition algorithm Résumé : This paper presents a new decomposition algorithm for the optimal scheduling of large-scale multiproduct plants containing a large number of orders. Rather than tackling highly complex, full-space problems that cannot be solved in reasonable time, the complete set of orders is scheduled sequentially by considering one, or a couple of them, at a time. As we proceed through the iterations, previously scheduled orders can be partly rescheduled to allow for some flexibility while keeping the combinatorial complexity at a manageable level. Once a complete schedule is obtained, the same concept is applied to improve the schedule locally. The user can choose to rely on either a unit-specific or a sequencing variable based continuous-time mixed-integer linear programming model. In addition, there are other parameters that affect how the decomposition is carried out, so the algorithm is highly versatile and adaptable to problems of varying sizes. The largest problem solved is a real-life, 50-order, 17-unit, 6-stage problem, for which a very good solution can be found in less than 1 min of computational time. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900734x Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11017–11033
Titre : Evaluation of synergy effect in the horizontal merger of companies in a petrochemical complex Type de document : texte imprimé Auteurs : Sung-Geun Yoon, Auteur ; Sunwon Park, Auteur ; Jeongseok Lee, Auteur Année de publication : 2010 Article en page(s) : pp. 11017–11033 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Mergers and acquisitions Petrochemical companies Résumé : Mergers and acquisitions (M&As) have been actively carried out in the petrochemical industry. However, the synergy created by the merger of petrochemical companies has seen relatively little study, despite being the primary goal of a merger. This study deals with the horizontal merger of petrochemical companies located within a single complex. Synergies considered in this work stem from integration of the process network and the utility plant, reduction of fixed costs, and contracts in purchasing and selling. A novel mathematical model that represents the operation of a process network and a utility plant and the decisions for purchasing and selling contracts is formulated. Four contracts for purchasing and selling are considered. The proposed model is applied to three Korean companies at a naphtha cracking center (NCC) located in the same industrial complex. The results show that synergy effects from integration of the process network and the utility system, reduction of fixed costs, and increased market share together increase profit by 50%. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900802v [article] Evaluation of synergy effect in the horizontal merger of companies in a petrochemical complex [texte imprimé] / Sung-Geun Yoon, Auteur ; Sunwon Park, Auteur ; Jeongseok Lee, Auteur . - 2010 . - pp. 11017–11033.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11017–11033
Mots-clés : Mergers and acquisitions Petrochemical companies Résumé : Mergers and acquisitions (M&As) have been actively carried out in the petrochemical industry. However, the synergy created by the merger of petrochemical companies has seen relatively little study, despite being the primary goal of a merger. This study deals with the horizontal merger of petrochemical companies located within a single complex. Synergies considered in this work stem from integration of the process network and the utility plant, reduction of fixed costs, and contracts in purchasing and selling. A novel mathematical model that represents the operation of a process network and a utility plant and the decisions for purchasing and selling contracts is formulated. Four contracts for purchasing and selling are considered. The proposed model is applied to three Korean companies at a naphtha cracking center (NCC) located in the same industrial complex. The results show that synergy effects from integration of the process network and the utility system, reduction of fixed costs, and increased market share together increase profit by 50%. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900802v Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11034–11047
Titre : Approximate predictive versus self-tuning adaptive control strategies of biodiesel reactors Type de document : texte imprimé Auteurs : Farouq S. Mjalli, Auteur ; Mohamed Azlan Hussain, Auteur Année de publication : 2010 Article en page(s) : pp. 11034–11047 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Palm oil Transesterification reactions Reactor nonlinearity Résumé : Producing biodiesel from palm oil as a raw material involves complex transesterification reactions which add up to the process nonlinearity. In this work, more emphasis will be focused on the reactor nonlinearity and ways of solving its control problem. The reactor nonlinearity is addressed via the application of an instantaneous linearization technique to control the reactor temperature and the triglyceride product concentration. A feed-forward neural network with delayed inputs and outputs was trained and validated to capture the dynamics of the biodiesel process. The generated nonlinear model was then utilized in an instantaneous linearization algorithm using two control algorithms adopting the self-tuning adaptive control and an approximate model predictive framework. The two algorithms were compared in terms of set-point tracking capability, efficiency, and stability. The minimum variance control algorithm attained poor performance compared to the pole-placement self-tuning adaptive algorithm. However, the approximate model predictive control strategy was superior to the self-tuning control in terms of its ability for forcing the output to follow the set-point trajectory efficiently with smooth controller moves. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900930k [article] Approximate predictive versus self-tuning adaptive control strategies of biodiesel reactors [texte imprimé] / Farouq S. Mjalli, Auteur ; Mohamed Azlan Hussain, Auteur . - 2010 . - pp. 11034–11047.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11034–11047
Mots-clés : Palm oil Transesterification reactions Reactor nonlinearity Résumé : Producing biodiesel from palm oil as a raw material involves complex transesterification reactions which add up to the process nonlinearity. In this work, more emphasis will be focused on the reactor nonlinearity and ways of solving its control problem. The reactor nonlinearity is addressed via the application of an instantaneous linearization technique to control the reactor temperature and the triglyceride product concentration. A feed-forward neural network with delayed inputs and outputs was trained and validated to capture the dynamics of the biodiesel process. The generated nonlinear model was then utilized in an instantaneous linearization algorithm using two control algorithms adopting the self-tuning adaptive control and an approximate model predictive framework. The two algorithms were compared in terms of set-point tracking capability, efficiency, and stability. The minimum variance control algorithm attained poor performance compared to the pole-placement self-tuning adaptive algorithm. However, the approximate model predictive control strategy was superior to the self-tuning control in terms of its ability for forcing the output to follow the set-point trajectory efficiently with smooth controller moves. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900930k Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11048–11059
Titre : Unusual control structure for high reflux ratio distillation columns Type de document : texte imprimé Auteurs : William L. Luyben, Auteur Année de publication : 2010 Article en page(s) : pp. 11048–11059 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Reflux ratio Distillation control wisdom Résumé : Distillation control wisdom suggests that reflux flow rate should be used to control the reflux-drum level when the reflux ratio is large (>3). In the typical case where a single-end temperature control structure is used, reboiler heat input is used to control a tray temperature at an appropriate location in the column. When the reflux ratio is large and reflux is used to control the reflux-drum level, a frequently used scheme controls the reflux ratio by measuring the reflux flow rate and rationing the distillate flow rate to the reflux flow rate. However, in many single-end distillation control structures, the inherent ability to handle feed composition disturbances is better for a fixed reflux-to-feed ratio than for a fixed reflux ratio. Using reflux to control the reflux-drum level precludes the use of this structure. This dilemma can be resolved by using an unusual control structure in which the reflux-drum level is controlled by reboiler heat input and a tray temperature is controlled by manipulating the distillate flow rate. The effectiveness of this nonconventional structure is demonstrated in this paper for a highly nonlinear azeotropic system of water, acetic acid, and formic acid. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9010589 [article] Unusual control structure for high reflux ratio distillation columns [texte imprimé] / William L. Luyben, Auteur . - 2010 . - pp. 11048–11059.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11048–11059
Mots-clés : Reflux ratio Distillation control wisdom Résumé : Distillation control wisdom suggests that reflux flow rate should be used to control the reflux-drum level when the reflux ratio is large (>3). In the typical case where a single-end temperature control structure is used, reboiler heat input is used to control a tray temperature at an appropriate location in the column. When the reflux ratio is large and reflux is used to control the reflux-drum level, a frequently used scheme controls the reflux ratio by measuring the reflux flow rate and rationing the distillate flow rate to the reflux flow rate. However, in many single-end distillation control structures, the inherent ability to handle feed composition disturbances is better for a fixed reflux-to-feed ratio than for a fixed reflux ratio. Using reflux to control the reflux-drum level precludes the use of this structure. This dilemma can be resolved by using an unusual control structure in which the reflux-drum level is controlled by reboiler heat input and a tray temperature is controlled by manipulating the distillate flow rate. The effectiveness of this nonconventional structure is demonstrated in this paper for a highly nonlinear azeotropic system of water, acetic acid, and formic acid. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9010589 Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11060–11070
Titre : Batch-to-batch steady state identification based on variable correlation and mahalanobis distance Type de document : texte imprimé Auteurs : Yuan Yao, Auteur ; Chunhui Zhao, Auteur ; Furong Gao, Auteur Année de publication : 2010 Article en page(s) : pp. 11060–11070 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Online steady state identification Multiway principal component analysis Résumé : Online steady state identification (SSID) is an important task to ensure the quality consistence of final products in batch processes. Additionally, it is also critical for satisfactory control of many batch processes. The existing approach for batch process SSID is based on the multiway principal component analysis (MPCA) method, which requires history data from dozens of batches for process modeling. Consequently, this limits its online applications. In this work, principal component analysis (PCA) models are built for each batch from which the variable correlation information is extracted. The changes in variable correlation structures are then quantified with a PCA similarity factor. At the same time, the Mahalanobis distances between batch trajectories are also calculated to indicate the changes in variable trajectory magnitudes. These two types of information are then used for online SSID in batch processes. This method is more suitable for online applications and can solve the problems of uneven operation durations. Additionally, it can be easily extended to deal with non-Gaussian information and multiphase batch process characteristics. Application examples show the effectiveness of the proposed method. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901107h [article] Batch-to-batch steady state identification based on variable correlation and mahalanobis distance [texte imprimé] / Yuan Yao, Auteur ; Chunhui Zhao, Auteur ; Furong Gao, Auteur . - 2010 . - pp. 11060–11070.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11060–11070
Mots-clés : Online steady state identification Multiway principal component analysis Résumé : Online steady state identification (SSID) is an important task to ensure the quality consistence of final products in batch processes. Additionally, it is also critical for satisfactory control of many batch processes. The existing approach for batch process SSID is based on the multiway principal component analysis (MPCA) method, which requires history data from dozens of batches for process modeling. Consequently, this limits its online applications. In this work, principal component analysis (PCA) models are built for each batch from which the variable correlation information is extracted. The changes in variable correlation structures are then quantified with a PCA similarity factor. At the same time, the Mahalanobis distances between batch trajectories are also calculated to indicate the changes in variable trajectory magnitudes. These two types of information are then used for online SSID in batch processes. This method is more suitable for online applications and can solve the problems of uneven operation durations. Additionally, it can be easily extended to deal with non-Gaussian information and multiphase batch process characteristics. Application examples show the effectiveness of the proposed method. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901107h Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11071–11080
Titre : Effect of feed tray location on temperature-based inferential control of double feed reactive distillation columns Type de document : texte imprimé Auteurs : Gülsah Sunar, Auteur ; Devrim B. Kaymak, Auteur Année de publication : 2010 Article en page(s) : pp. 11071–11080 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Feed tray location Reactive distillation columns Résumé : Adjusting the feed tray locations may result in significant energy savings for double feed reactive distillation columns. In the literature, composition-based control structures have been suggested for the internally heat integrated designs of ideal reactive distillation columns. This paper explores the effect of feed tray location on the controllability of ideal reactive distillation columns using temperature-based control structures. Two different types of two-temperature inferential control structures are considered. In the first structure, two fresh feed flow rates are manipulated to control the temperatures on two selected trays. In the second structure, the light fresh feed flow rate and the vapor boilup are manipulated. Alternative designs are created by moving the feed trays in and out of the reactive zone. It is demonstrated that significant energy savings are obtained by shifting the feed tray locations into the reactive zone. The results indicate that there are internally heat integrated designs, which can be effectively controlled by a two-temperature inferential control structure without using any direct composition measurement. For the case study examined, a 13.17% energy saving is obtained by shifting the fresh feed trays into the reactive zone by two trays from their conventional locations. The second temperature-based control structure considered can handle fairly large throughput changes without any system shut down or steady-state transition for this energy-efficient design. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901142s [article] Effect of feed tray location on temperature-based inferential control of double feed reactive distillation columns [texte imprimé] / Gülsah Sunar, Auteur ; Devrim B. Kaymak, Auteur . - 2010 . - pp. 11071–11080.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11071–11080
Mots-clés : Feed tray location Reactive distillation columns Résumé : Adjusting the feed tray locations may result in significant energy savings for double feed reactive distillation columns. In the literature, composition-based control structures have been suggested for the internally heat integrated designs of ideal reactive distillation columns. This paper explores the effect of feed tray location on the controllability of ideal reactive distillation columns using temperature-based control structures. Two different types of two-temperature inferential control structures are considered. In the first structure, two fresh feed flow rates are manipulated to control the temperatures on two selected trays. In the second structure, the light fresh feed flow rate and the vapor boilup are manipulated. Alternative designs are created by moving the feed trays in and out of the reactive zone. It is demonstrated that significant energy savings are obtained by shifting the feed tray locations into the reactive zone. The results indicate that there are internally heat integrated designs, which can be effectively controlled by a two-temperature inferential control structure without using any direct composition measurement. For the case study examined, a 13.17% energy saving is obtained by shifting the fresh feed trays into the reactive zone by two trays from their conventional locations. The second temperature-based control structure considered can handle fairly large throughput changes without any system shut down or steady-state transition for this energy-efficient design. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901142s Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11081–11093
Titre : Design and control of an autorefrigerated alkylation process Type de document : texte imprimé Auteurs : William L. Luyben, Auteur Année de publication : 2010 Article en page(s) : pp. 11081–11093 Note générale : Chemical engineering Langues : Anglais (eng) Résumé : The alkylation of C4 olefins with isobutane to produce high-octane C8 components (“alkylate”) is a very important process in many oil refineries. The Kellogg process uses a sulfuric acid catalyst in a series of agitated reactors, which must operate at temperatures that require refrigeration because of undesirable side reactions that are favored by high temperatures. The reactors are cooled by boiling the liquid in the reactor, compressing the vapor, condensing it, and returning the liquid back to the reactor. A large excess of isobutane is used to suppress undesirable reactions, which requires a large recycle stream. Inert components (propane and n-butane) that enter in the fresh feed streams must be purged from the system. Two distillation columns are used, one of which has a vapor sidestream in addition to distillate and bottoms streams. This paper studies a simplified version of the autorefrigerated alkylation process and demonstrates the design trade-offs and interaction among design optimization variables such as reactor size, reactor temperature, compressor work, and isobutane recycle. Large reactors permit lower temperatures for a given olefin conversion, which improves selectivity. However, low reactor temperatures produce a low reactor pressure, which increases compressor work. Higher isobutane recycle improves selectivity but increases energy consumption and equipment sizes in the separation section. So the optimum economic design must balance the capital costs of reactors and distillation columns with the energy costs of compression and reboiler heat inputs. The location where the fresh feed streams enter the process also affects the design. An effective plantwide control structure is also developed that handles large disturbances in throughput and feed compositions. The structure has several uncommon control features: control of two compositions and one temperature in the sidestream column and a proportional-only temperature control in the other column. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9012387 [article] Design and control of an autorefrigerated alkylation process [texte imprimé] / William L. Luyben, Auteur . - 2010 . - pp. 11081–11093.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11081–11093
Résumé : The alkylation of C4 olefins with isobutane to produce high-octane C8 components (“alkylate”) is a very important process in many oil refineries. The Kellogg process uses a sulfuric acid catalyst in a series of agitated reactors, which must operate at temperatures that require refrigeration because of undesirable side reactions that are favored by high temperatures. The reactors are cooled by boiling the liquid in the reactor, compressing the vapor, condensing it, and returning the liquid back to the reactor. A large excess of isobutane is used to suppress undesirable reactions, which requires a large recycle stream. Inert components (propane and n-butane) that enter in the fresh feed streams must be purged from the system. Two distillation columns are used, one of which has a vapor sidestream in addition to distillate and bottoms streams. This paper studies a simplified version of the autorefrigerated alkylation process and demonstrates the design trade-offs and interaction among design optimization variables such as reactor size, reactor temperature, compressor work, and isobutane recycle. Large reactors permit lower temperatures for a given olefin conversion, which improves selectivity. However, low reactor temperatures produce a low reactor pressure, which increases compressor work. Higher isobutane recycle improves selectivity but increases energy consumption and equipment sizes in the separation section. So the optimum economic design must balance the capital costs of reactors and distillation columns with the energy costs of compression and reboiler heat inputs. The location where the fresh feed streams enter the process also affects the design. An effective plantwide control structure is also developed that handles large disturbances in throughput and feed compositions. The structure has several uncommon control features: control of two compositions and one temperature in the sidestream column and a proportional-only temperature control in the other column. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9012387 Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11094–11107
Titre : Supply chain redesign : multimodal optimization using a hybrid evolutionary algorithm Type de document : texte imprimé Auteurs : P. K. Naraharisetti, Auteur ; Iftekhar A. Karimi, Auteur ; Rajagopalan Srinivasan, Auteur Année de publication : 2010 Article en page(s) : pp. 11094–11107 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Supply chain redesign Hybrid evolutionary algorithm Résumé : Supply chain redesign (SCR) involves decisions regarding the timings, amounts, and locations of the investment and disinvestment in facilities, production, material purchase, product sales, contracts, capital-raising loans and bonds, etc. such that the profit is maximized. SCR is a heavily constrained problem; hence as the problem size increases, the MILP formulations (Naraharisetti, P. K.; Karimi, I. A.; Srinivasan, R. Supply Chain Redesign through Optimal Asset Management and Capital Budgeting. Comput. Chem. Eng. 2008, 32, 3153−3169) become increasingly difficult to solve. In addition, MILP solvers typically give only one solution, while multiple optimal solutions may be desirable in practice. Hence, an alternative optimization technique is warranted. In this work, we propose a hybrid MILP−evolutionary algorithm strategy for supply chain redesign and present progress on three fronts: (a) a novel reformulation of the MILP in which most decision variables are unconstrained and the rest can be easily repaired to satisfy constraints, (b) a single-objective hybrid optimization algorithm that uses an evolutionary search and reaches 97% of the objective value attained by CPlex 9.0 on a small example, while outperforming CPlex 9.0 on a large SCR problem, and (c) a multimodal algorithm that identifies multiple supply chain networks with 90−95% of the objective value obtained by CPlex 9.0. Finally, we analyze the effect of uncertainty on each supply chain network identified by our multimodal algorithm. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9002574 [article] Supply chain redesign : multimodal optimization using a hybrid evolutionary algorithm [texte imprimé] / P. K. Naraharisetti, Auteur ; Iftekhar A. Karimi, Auteur ; Rajagopalan Srinivasan, Auteur . - 2010 . - pp. 11094–11107.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11094–11107
Mots-clés : Supply chain redesign Hybrid evolutionary algorithm Résumé : Supply chain redesign (SCR) involves decisions regarding the timings, amounts, and locations of the investment and disinvestment in facilities, production, material purchase, product sales, contracts, capital-raising loans and bonds, etc. such that the profit is maximized. SCR is a heavily constrained problem; hence as the problem size increases, the MILP formulations (Naraharisetti, P. K.; Karimi, I. A.; Srinivasan, R. Supply Chain Redesign through Optimal Asset Management and Capital Budgeting. Comput. Chem. Eng. 2008, 32, 3153−3169) become increasingly difficult to solve. In addition, MILP solvers typically give only one solution, while multiple optimal solutions may be desirable in practice. Hence, an alternative optimization technique is warranted. In this work, we propose a hybrid MILP−evolutionary algorithm strategy for supply chain redesign and present progress on three fronts: (a) a novel reformulation of the MILP in which most decision variables are unconstrained and the rest can be easily repaired to satisfy constraints, (b) a single-objective hybrid optimization algorithm that uses an evolutionary search and reaches 97% of the objective value attained by CPlex 9.0 on a small example, while outperforming CPlex 9.0 on a large SCR problem, and (c) a multimodal algorithm that identifies multiple supply chain networks with 90−95% of the objective value obtained by CPlex 9.0. Finally, we analyze the effect of uncertainty on each supply chain network identified by our multimodal algorithm. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9002574 Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11108–11114
Titre : Batch-to-batch iterative learning control of a batch polymerization process based on online sequential extreme learning machine Type de document : texte imprimé Auteurs : Tang Ao, Auteur ; Xiao Dong, Auteur ; Mao Zhizhong, Auteur Année de publication : 2010 Article en page(s) : pp. 11108–11114 Note générale : Chemical engineeringg Langues : Anglais (eng) Mots-clés : Batch-to-batch iterative learning control Online sequential extreme machine Extreme Résumé : This paper develops a batch-to-batch iterative learning control (ILC) strategy based on online sequential extreme learning machine (OS-ELM) for batch optimal control. On the basis of extreme learning machine (ELM), a data-based nonlinear model is first adopted to capture the batch process characteristics aiming to obtain superior predictive accuracy. Subsequently, due to the model−plant mismatch in real batch processes, an ILC algorithm with adjusting input trajectory by means of error feedback is employed focusing on the improvement of the final product quality. In order to cope with the problems of the unknown disturbances and process variations from batch to batch, when a batch run is completed, OS-ELM is utilized to update the model weights so as to guarantee the precision of the model for optimal control, which corresponds to a nonlinear updating procedure. The feasibility and effectiveness of the proposed method are demonstrated via the application to a simulated bulk polymerization of the styrene batch process, and the simulation results show superior performance. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9007979 [article] Batch-to-batch iterative learning control of a batch polymerization process based on online sequential extreme learning machine [texte imprimé] / Tang Ao, Auteur ; Xiao Dong, Auteur ; Mao Zhizhong, Auteur . - 2010 . - pp. 11108–11114.
Chemical engineeringg
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11108–11114
Mots-clés : Batch-to-batch iterative learning control Online sequential extreme machine Extreme Résumé : This paper develops a batch-to-batch iterative learning control (ILC) strategy based on online sequential extreme learning machine (OS-ELM) for batch optimal control. On the basis of extreme learning machine (ELM), a data-based nonlinear model is first adopted to capture the batch process characteristics aiming to obtain superior predictive accuracy. Subsequently, due to the model−plant mismatch in real batch processes, an ILC algorithm with adjusting input trajectory by means of error feedback is employed focusing on the improvement of the final product quality. In order to cope with the problems of the unknown disturbances and process variations from batch to batch, when a batch run is completed, OS-ELM is utilized to update the model weights so as to guarantee the precision of the model for optimal control, which corresponds to a nonlinear updating procedure. The feasibility and effectiveness of the proposed method are demonstrated via the application to a simulated bulk polymerization of the styrene batch process, and the simulation results show superior performance. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9007979 Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11115–11132
Titre : Optimization of adiabatic styrene reactor : a hybrid multiobjective differential evolution (H-MODE) approach Type de document : texte imprimé Auteurs : Ashish M. Gujarathi, Auteur ; B. V. Babu, Auteur Année de publication : 2010 Article en page(s) : pp. 11115–11132 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hybrid-mode algorithm Résumé : In this study, a hybrid strategy of multiobjective differential evolution (hybrid-MODE) algorithm is proposed that consists of an evolutionary algorithm for global search and a deterministic algorithm for local search. To begin, the proposed algorithm is tested for its performance using a benchmark test function (KUR) as case study 1 with the nondominated sorting genetic algorithm-II (NSGA-II) (both binary- and real-coded versions), strength Pareto evolutionary algorithm (SPEA), Pareto archived evolutionary strategy (PAES), multiobjective differential evolution (MODE), and an improved strategy of MODE algorithms. Subsequently, the multiobjective optimization of an industrial adiabatic styrene reactor is carried out as case study 2, employing a prevalidated model using the hybrid-MODE algorithm and an improved strategy of MODE. Four cases (three sets of two-objective optimization, cases 1−3, and one set of three-objective optimization, case 4) are considered consisting of simultaneous maximization of styrene productivity, selectivity, and yield with four decision variables and two constraints. The proposed algorithm converges to a better set of nondominated solutions (possibly a Pareto front) as compared to the nondominated solutions obtained using NSGA and an improved strategy of MODE algorithms. The limitations of previous studies are reported in terms of key decision variables. The hybrid strategy of MODE is found to converge to the true Pareto front more rapidly (in fewer function evaluations), resulting in a well-diversified Pareto front as compared to the stand-alone evolutionary approach. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901074k [article] Optimization of adiabatic styrene reactor : a hybrid multiobjective differential evolution (H-MODE) approach [texte imprimé] / Ashish M. Gujarathi, Auteur ; B. V. Babu, Auteur . - 2010 . - pp. 11115–11132.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11115–11132
Mots-clés : Hybrid-mode algorithm Résumé : In this study, a hybrid strategy of multiobjective differential evolution (hybrid-MODE) algorithm is proposed that consists of an evolutionary algorithm for global search and a deterministic algorithm for local search. To begin, the proposed algorithm is tested for its performance using a benchmark test function (KUR) as case study 1 with the nondominated sorting genetic algorithm-II (NSGA-II) (both binary- and real-coded versions), strength Pareto evolutionary algorithm (SPEA), Pareto archived evolutionary strategy (PAES), multiobjective differential evolution (MODE), and an improved strategy of MODE algorithms. Subsequently, the multiobjective optimization of an industrial adiabatic styrene reactor is carried out as case study 2, employing a prevalidated model using the hybrid-MODE algorithm and an improved strategy of MODE. Four cases (three sets of two-objective optimization, cases 1−3, and one set of three-objective optimization, case 4) are considered consisting of simultaneous maximization of styrene productivity, selectivity, and yield with four decision variables and two constraints. The proposed algorithm converges to a better set of nondominated solutions (possibly a Pareto front) as compared to the nondominated solutions obtained using NSGA and an improved strategy of MODE algorithms. The limitations of previous studies are reported in terms of key decision variables. The hybrid strategy of MODE is found to converge to the true Pareto front more rapidly (in fewer function evaluations), resulting in a well-diversified Pareto front as compared to the stand-alone evolutionary approach. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901074k Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11133–11139
Titre : Quantitative study on polymorphic form in solution crystallization of clopidogrel hydrogen sulfate Type de document : texte imprimé Auteurs : Hye-Jin Kim, Auteur ; Kwang-Joo Kim, Auteur Année de publication : 2010 Article en page(s) : pp. 11133–11139 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Polymorphs Crystallized solid Ultrasonic velocity Résumé : The concentration of polymorphs was explored by the ultrasonic measuring technique during crystallization in solution. The polymorphic form of the crystallized solid, the concentration of the solution, and the transformation of polymorphs were found by the ultrasonic measuring technique. The ultrasonic velocity calibrated at known solid and liquid concentrations has been applied to determine quantitatively the polymorphic compositions for various process conditions. Additionally, it can be used to estimate the solute concentration and the supersaturation of solution during the transformation of polymorphs. Multivariate data analysis from the ultrasonic measuring technique was used to determine the kinetics of polymorph transformation and to simulate the transformation process. It was found that the transformation of polymorphs occurred simultaneously with crystallization of a polymorph in the solution. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900715w [article] Quantitative study on polymorphic form in solution crystallization of clopidogrel hydrogen sulfate [texte imprimé] / Hye-Jin Kim, Auteur ; Kwang-Joo Kim, Auteur . - 2010 . - pp. 11133–11139.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11133–11139
Mots-clés : Polymorphs Crystallized solid Ultrasonic velocity Résumé : The concentration of polymorphs was explored by the ultrasonic measuring technique during crystallization in solution. The polymorphic form of the crystallized solid, the concentration of the solution, and the transformation of polymorphs were found by the ultrasonic measuring technique. The ultrasonic velocity calibrated at known solid and liquid concentrations has been applied to determine quantitatively the polymorphic compositions for various process conditions. Additionally, it can be used to estimate the solute concentration and the supersaturation of solution during the transformation of polymorphs. Multivariate data analysis from the ultrasonic measuring technique was used to determine the kinetics of polymorph transformation and to simulate the transformation process. It was found that the transformation of polymorphs occurred simultaneously with crystallization of a polymorph in the solution. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900715w Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11140–11147
Titre : Continuous CO2 capture from flue gases using a dual fluidized bed reactor with calcium-based sorbent Type de document : texte imprimé Auteurs : Fan Fang, Auteur ; Zhen-shan Li, Auteur ; Ning-sheng Cai, Auteur Année de publication : 2010 Article en page(s) : pp. 11140–11147 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : CO2 capture Dual fluidized bed reactors Résumé : CO2 capture using multiple carbonation and calcination reaction looping is an emerging postcombustion capture technology. Dual fluidized bed reactors are the key technology to fulfill the carbonation/calcination looping process. Dual bubbling fluidized bed reactors were constructed to demonstrate the process feasibility of continuous CO2 capture from flue gases. First, a cold model of the dual bubbling fluidized bed reactor was built and tested on the foundation of analyzing different types of dual fluidized bed reactors. Long-term stable operation and continuous solids circulation between the two reactors was achieved in the cold model. The solids circulation rate increased with increasing bed material height, solid injection nozzle diameter, and hole diameter on the solid injection nozzle. Second, a hot model of the dual bubbling fluidized bed reactor was constructed. The sorbent particles successfully circulated between the carbonator and the regenerator at high temperatures and the CO2 in the flue gases was continuously captured by the Ca-based sorbent, dolomite. Experimental results indicate that ∼95.0% CO2 capture efficiency could be achieved. In the carbonator, about 70.4% CaO in the sorbent was converted to CaCO3. In the regenerator, the CaCO3 did not decompose completely with more than 13.9 wt % CaCO3 still in the sorbent leaving the regenerator. The carbonation temperature and the sorbent attrition were found to significantly influence the carbonation/calcination looping process. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901128r [article] Continuous CO2 capture from flue gases using a dual fluidized bed reactor with calcium-based sorbent [texte imprimé] / Fan Fang, Auteur ; Zhen-shan Li, Auteur ; Ning-sheng Cai, Auteur . - 2010 . - pp. 11140–11147.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11140–11147
Mots-clés : CO2 capture Dual fluidized bed reactors Résumé : CO2 capture using multiple carbonation and calcination reaction looping is an emerging postcombustion capture technology. Dual fluidized bed reactors are the key technology to fulfill the carbonation/calcination looping process. Dual bubbling fluidized bed reactors were constructed to demonstrate the process feasibility of continuous CO2 capture from flue gases. First, a cold model of the dual bubbling fluidized bed reactor was built and tested on the foundation of analyzing different types of dual fluidized bed reactors. Long-term stable operation and continuous solids circulation between the two reactors was achieved in the cold model. The solids circulation rate increased with increasing bed material height, solid injection nozzle diameter, and hole diameter on the solid injection nozzle. Second, a hot model of the dual bubbling fluidized bed reactor was constructed. The sorbent particles successfully circulated between the carbonator and the regenerator at high temperatures and the CO2 in the flue gases was continuously captured by the Ca-based sorbent, dolomite. Experimental results indicate that ∼95.0% CO2 capture efficiency could be achieved. In the carbonator, about 70.4% CaO in the sorbent was converted to CaCO3. In the regenerator, the CaCO3 did not decompose completely with more than 13.9 wt % CaCO3 still in the sorbent leaving the regenerator. The carbonation temperature and the sorbent attrition were found to significantly influence the carbonation/calcination looping process. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901128r Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11148–11157
Titre : Optimization and analysis of possible column arrangements for multicomponent separations by preparative chromatography Type de document : texte imprimé Auteurs : Javier García Palacios, Auteur ; Malte Kaspereit, Auteur ; Grzegorz Ziomek, Auteur Année de publication : 2010 Article en page(s) : pp. 11148–11157 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Chromatographic columns Ternary mixture Résumé : The optimal arrangement of eight identical chromatographic columns for the isolation of the intermediate adsorbing component of a ternary mixture is investigated theoretically. The arrangements considered are batch chromatography with columns connected in series and/or in parallel, cascades of two standard simulated moving bed (SMB) processes, and combinations of standard SMB units and batch columns. Based on standard column models, the productivity of each configuration was maximized by optimizing the relevant operating parameters using a modified simplex algorithm. The methodology applied allows us to evaluate all possible batch column arrangements on the basis of only eight different optimization runs. The results obtained reveal a significant dependency of the optimal process configuration on relevant aspects such as product purity, feed composition, and particle size of the adsorbent. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900361m [article] Optimization and analysis of possible column arrangements for multicomponent separations by preparative chromatography [texte imprimé] / Javier García Palacios, Auteur ; Malte Kaspereit, Auteur ; Grzegorz Ziomek, Auteur . - 2010 . - pp. 11148–11157.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11148–11157
Mots-clés : Chromatographic columns Ternary mixture Résumé : The optimal arrangement of eight identical chromatographic columns for the isolation of the intermediate adsorbing component of a ternary mixture is investigated theoretically. The arrangements considered are batch chromatography with columns connected in series and/or in parallel, cascades of two standard simulated moving bed (SMB) processes, and combinations of standard SMB units and batch columns. Based on standard column models, the productivity of each configuration was maximized by optimizing the relevant operating parameters using a modified simplex algorithm. The methodology applied allows us to evaluate all possible batch column arrangements on the basis of only eight different optimization runs. The results obtained reveal a significant dependency of the optimal process configuration on relevant aspects such as product purity, feed composition, and particle size of the adsorbent. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900361m Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11158–11161
Titre : Reduced-heat transfer area reactor for scale-up study of batch cooling crystallization Type de document : texte imprimé Auteurs : Huiyong Kim, Auteur ; Kwang Soon Lee, Auteur Année de publication : 2010 Article en page(s) : pp. 11158–11161 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Batch cooling crystallization Reactor Jacket heat transfer area Résumé : A method to facilitate the scale-up study for batch cooling crystallization using a reactor which has reduced jacket heat transfer area is proposed. It is shown that the thermal behavior of a 30 L or larger reactor can be replicated using a 1 L reactor by blocking a part of the jacket area from the heat transfer to achieve 30 times or larger volume scale-up effect. The proposed method has an additional advantage in that the hydrodynamics are intact and the effects on the thermal behavior can be investigated separately. A usage of the proposed method is demonstrated for seed amount determination in batch cooling crystallization of ammonium sulfate. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900444q [article] Reduced-heat transfer area reactor for scale-up study of batch cooling crystallization [texte imprimé] / Huiyong Kim, Auteur ; Kwang Soon Lee, Auteur . - 2010 . - pp. 11158–11161.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11158–11161
Mots-clés : Batch cooling crystallization Reactor Jacket heat transfer area Résumé : A method to facilitate the scale-up study for batch cooling crystallization using a reactor which has reduced jacket heat transfer area is proposed. It is shown that the thermal behavior of a 30 L or larger reactor can be replicated using a 1 L reactor by blocking a part of the jacket area from the heat transfer to achieve 30 times or larger volume scale-up effect. The proposed method has an additional advantage in that the hydrodynamics are intact and the effects on the thermal behavior can be investigated separately. A usage of the proposed method is demonstrated for seed amount determination in batch cooling crystallization of ammonium sulfate. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900444q Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11162–11167
Titre : Supercritical antisolvent micronization of cyclotrimethylenetrinitramin : influence of the organic solvent Type de document : texte imprimé Auteurs : Byoung-Min Lee, Auteur ; Jin-Seong Jeong, Auteur ; Young-Ho Lee, Auteur Année de publication : 2010 Article en page(s) : pp. 11162–11167 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Supercritical antisolvent Micronized cyclotrimethylenetrinitramin Résumé : A supercritical antisolvent (SAS) process was used to prepare micronized cyclotrimethylenetrinitramin (RDX). This study examined the influence of different solvents at a fixed temperature (50 °C) and pressure (13.7 or 15 MPa) on the morphology, particle size (PS), and particle size distribution (PSD) using a semicontinuous SAS process. Dimethyl sulfoxide (DMSO), dimethylformamide (DMF), acetone (AC), acetonitrile (ACN), n-methyl 2-pyrrolidone (NMP), and cyclohexanone (CHN) were used as solvents. The recrystallized RDX particles were characterized by scanning electron microscopy (SEM), particle size analyzer (PSA), Fourier transform infrared (FT-IR) spectroscopy, and differential scanning calorimetry (DSC). Depending on the solvent used, the recrystallized RDX particles showed a variety of morphologies, particle sizes, and particle size distributions (PSD). The mean particle size of the recrystallized RDX ranged from 2.6 to 17.7 μm. The enthalpy change (ΔH = 583.4, 847.7, 967.1, 823.9, 1131, and 1620 J/g) for the exothermic decomposition of recrystallized RDX was much higher than that of the unprocessed RDX (ΔH = 381.5 J/g). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900448w [article] Supercritical antisolvent micronization of cyclotrimethylenetrinitramin : influence of the organic solvent [texte imprimé] / Byoung-Min Lee, Auteur ; Jin-Seong Jeong, Auteur ; Young-Ho Lee, Auteur . - 2010 . - pp. 11162–11167.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11162–11167
Mots-clés : Supercritical antisolvent Micronized cyclotrimethylenetrinitramin Résumé : A supercritical antisolvent (SAS) process was used to prepare micronized cyclotrimethylenetrinitramin (RDX). This study examined the influence of different solvents at a fixed temperature (50 °C) and pressure (13.7 or 15 MPa) on the morphology, particle size (PS), and particle size distribution (PSD) using a semicontinuous SAS process. Dimethyl sulfoxide (DMSO), dimethylformamide (DMF), acetone (AC), acetonitrile (ACN), n-methyl 2-pyrrolidone (NMP), and cyclohexanone (CHN) were used as solvents. The recrystallized RDX particles were characterized by scanning electron microscopy (SEM), particle size analyzer (PSA), Fourier transform infrared (FT-IR) spectroscopy, and differential scanning calorimetry (DSC). Depending on the solvent used, the recrystallized RDX particles showed a variety of morphologies, particle sizes, and particle size distributions (PSD). The mean particle size of the recrystallized RDX ranged from 2.6 to 17.7 μm. The enthalpy change (ΔH = 583.4, 847.7, 967.1, 823.9, 1131, and 1620 J/g) for the exothermic decomposition of recrystallized RDX was much higher than that of the unprocessed RDX (ΔH = 381.5 J/g). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900448w Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11168–11174
Titre : Performance of several ionic liquids for the separation of 1-octene from n-octane Type de document : texte imprimé Auteurs : Gary J. Belluomini, Auteur ; John G. Pendergast, Auteur ; Christopher H. Domke, Auteur Année de publication : 2010 Article en page(s) : pp. 11168–11174 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Several ionic liquids 1-octene n-octane Résumé : This paper reports on the performance of several ionic liquids for use in separating an olefin (1-octene) from a paraffin (n-octane). To quantify the effectiveness of an ionic liquid in a given separation, a measurement of the activity coefficients of the solutes in the solvent can be used as a guide. This measurement permits the calculation of selectivities and capacities that are important factors in judging the suitability and potential commercial viability of an ionic liquid for a separation application. Several different ionic liquids were tested and compared to a traditional, conventional solvent, N-methyl-pyrrolidone (NMP), and to each other. One ionic liquid tested, silver(I)/N,N-dimethylbenzoamide bis(trifluoromethylsulfonyl) imide [Ag(DMBA)2+Tf2N−], showed selectivities 24−32 times higher than NMP while maintaining a comparable mass capacity as the nonionic solvent. The experimental data showed that this particular ionic liquid was also superior to any of the other ionic liquids tested in this series of experiments. This ionic liquid has the potential to be used in an economically viable commercial process to recover valuable olefinic components from streams where they are mixed with paraffins. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9009815 [article] Performance of several ionic liquids for the separation of 1-octene from n-octane [texte imprimé] / Gary J. Belluomini, Auteur ; John G. Pendergast, Auteur ; Christopher H. Domke, Auteur . - 2010 . - pp. 11168–11174.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11168–11174
Mots-clés : Several ionic liquids 1-octene n-octane Résumé : This paper reports on the performance of several ionic liquids for use in separating an olefin (1-octene) from a paraffin (n-octane). To quantify the effectiveness of an ionic liquid in a given separation, a measurement of the activity coefficients of the solutes in the solvent can be used as a guide. This measurement permits the calculation of selectivities and capacities that are important factors in judging the suitability and potential commercial viability of an ionic liquid for a separation application. Several different ionic liquids were tested and compared to a traditional, conventional solvent, N-methyl-pyrrolidone (NMP), and to each other. One ionic liquid tested, silver(I)/N,N-dimethylbenzoamide bis(trifluoromethylsulfonyl) imide [Ag(DMBA)2+Tf2N−], showed selectivities 24−32 times higher than NMP while maintaining a comparable mass capacity as the nonionic solvent. The experimental data showed that this particular ionic liquid was also superior to any of the other ionic liquids tested in this series of experiments. This ionic liquid has the potential to be used in an economically viable commercial process to recover valuable olefinic components from streams where they are mixed with paraffins. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9009815 Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11175–11180
Titre : Simultaneous absorption of CO2 and NH3 into water in a rotating packed bed Type de document : texte imprimé Auteurs : Bao-Chang Sun, Auteur ; Xue-Mei Wang, Auteur ; Jian-Ming Chen, Auteur Année de publication : 2010 Article en page(s) : pp. 11175–11180 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : CO2 NH3 Rotating packed bed Overall volumetric mass-transfer coefficients Résumé : This article presents the modeling and experimental investigation of the simultaneous absorption of CO2 and NH3 into water in a rotating packed bed (RPB). A model was established to predict the overall volumetric mass-transfer coefficients (KGa) of CO2 and NH3 with reactions in the RPB at gravity levels of about 70−250g. Experiments involving the simultaneous absorption of CO2 and NH3 into water in an RPB were carried out under different conditions, and it was found that KGa increased with increasing rotation speed, liquid volumetric flow rate, gas volumetric flow rate, and NH3/CO2 molar ratio. It was observed that the model was in good agreement with the experimental data, with deviations within 10% compared to the experimental values. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9001316 [article] Simultaneous absorption of CO2 and NH3 into water in a rotating packed bed [texte imprimé] / Bao-Chang Sun, Auteur ; Xue-Mei Wang, Auteur ; Jian-Ming Chen, Auteur . - 2010 . - pp. 11175–11180.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11175–11180
Mots-clés : CO2 NH3 Rotating packed bed Overall volumetric mass-transfer coefficients Résumé : This article presents the modeling and experimental investigation of the simultaneous absorption of CO2 and NH3 into water in a rotating packed bed (RPB). A model was established to predict the overall volumetric mass-transfer coefficients (KGa) of CO2 and NH3 with reactions in the RPB at gravity levels of about 70−250g. Experiments involving the simultaneous absorption of CO2 and NH3 into water in an RPB were carried out under different conditions, and it was found that KGa increased with increasing rotation speed, liquid volumetric flow rate, gas volumetric flow rate, and NH3/CO2 molar ratio. It was observed that the model was in good agreement with the experimental data, with deviations within 10% compared to the experimental values. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9001316 Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11181–11188
Titre : Fluid dynamic study of a semicylindrical spouted bed : evaluation of the shear stress effects in the flat wall region using computational fluid dynamics Type de document : texte imprimé Auteurs : Rodrigo Béttega, Auteur ; Cezar A. da Rosa, Auteur ; Ronaldo G. Corrêa, Auteur Année de publication : 2010 Article en page(s) : pp. 11181–11188 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Cylindrical vessels Semicylindrical spouted beds Computational fluid dynamics Résumé : Using a semicylindrical spouted bed to obtain experimental data of cylindrical vessels is an old technique and it has already been widely studied by experimental procedures. In the mathematical modeling of semicylindrical spouted beds, the specularity coefficient is one of the ways of including the effect of shear stress in the solid phase promoted by the flat wall. This parameter can be included in the boundary condition of a semicylindrical spouted bed to represent this friction effect. The main purpose of this paper is to discuss the numerical influence of the specularity coefficient on the fluid and solid dynamics of the semicylindrical vessel. Several numerical simulations were performed using the CFD (computational fluid dynamics) technique, by Euler−Euler 3D modeling, for different parameter values of the specularity coefficient. Experimental pressure data are used to verify these simulations. Numerical and experimental results showed good agreement, and the simulations indicated that particle velocity profiles and solid volume fraction were strongly influenced by the specularity coefficient on the spout channel region. Nonetheless, numerical static pressure and fluid velocity have not presented considerable dependence on this coefficient. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900973x [article] Fluid dynamic study of a semicylindrical spouted bed : evaluation of the shear stress effects in the flat wall region using computational fluid dynamics [texte imprimé] / Rodrigo Béttega, Auteur ; Cezar A. da Rosa, Auteur ; Ronaldo G. Corrêa, Auteur . - 2010 . - pp. 11181–11188.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11181–11188
Mots-clés : Cylindrical vessels Semicylindrical spouted beds Computational fluid dynamics Résumé : Using a semicylindrical spouted bed to obtain experimental data of cylindrical vessels is an old technique and it has already been widely studied by experimental procedures. In the mathematical modeling of semicylindrical spouted beds, the specularity coefficient is one of the ways of including the effect of shear stress in the solid phase promoted by the flat wall. This parameter can be included in the boundary condition of a semicylindrical spouted bed to represent this friction effect. The main purpose of this paper is to discuss the numerical influence of the specularity coefficient on the fluid and solid dynamics of the semicylindrical vessel. Several numerical simulations were performed using the CFD (computational fluid dynamics) technique, by Euler−Euler 3D modeling, for different parameter values of the specularity coefficient. Experimental pressure data are used to verify these simulations. Numerical and experimental results showed good agreement, and the simulations indicated that particle velocity profiles and solid volume fraction were strongly influenced by the specularity coefficient on the spout channel region. Nonetheless, numerical static pressure and fluid velocity have not presented considerable dependence on this coefficient. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900973x Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11189–11201
Titre : Modeling pVT properties and phase equilibria for systems containing ionic liquids using a new lattice-fluid equation of state Type de document : texte imprimé Auteurs : Xiaochun Xu, Auteur ; Changjun Peng, Auteur ; Honglai Liu, Auteur Année de publication : 2010 Article en page(s) : pp. 11189–11201 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ionic liquids Chainlike structures Résumé : The cations or anions of ionic liquids (ILs) usually have long alkyl chains or chainlike structures. Therefore, ILs can be reasonably considered as fluids containing neutral chainlike molecules. Lattice-based molecular thermodynamic models generally used for polymer systems can be applied to describe the thermodynamic properties and phase behavior of IL systems. In our previous work, a new lattice-fluid equation of state (LF EoS) was developed and successfully applied to normal fluid systems (Xu et al., Fluid Phase Equilib. 2008, 265, 112.). In this work, this LF EoS is further extended to model the pVT properties and phase equilibria of IL systems. The molecular parameters of ILs in this EoS were determined by correlating the experimental pVT data of pure ILs. It is shown that the pVT behavior of IL mixtures can be fairly well predicted by these parameters. The vapor−liquid equilibria (VLE) of binary IL−solvent systems were calculated by using an adjustable binary parameter, κ12. For liquid−liquid equilibria (LLE) of binary IL systems, a parameter Cr describing the effect of the mixture composition on the chain-length parameter r is further used, and satisfactory correlation is obtained. The upper critical solution temperature (UCST) can be predicted successfully. Moreover, the EoS reproduces the solubility data for carbon dioxide (CO2) in various ILs covering a wide range of pressures (0−100 MPa), and it describes the global behavior of trifluoromethane (CHF3) and IL mixtures. The results reveal that the LF EoS is well-suited for the calculation or prediction of the thermodynamic properties of systems containing ILs. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9011722 [article] Modeling pVT properties and phase equilibria for systems containing ionic liquids using a new lattice-fluid equation of state [texte imprimé] / Xiaochun Xu, Auteur ; Changjun Peng, Auteur ; Honglai Liu, Auteur . - 2010 . - pp. 11189–11201.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11189–11201
Mots-clés : Ionic liquids Chainlike structures Résumé : The cations or anions of ionic liquids (ILs) usually have long alkyl chains or chainlike structures. Therefore, ILs can be reasonably considered as fluids containing neutral chainlike molecules. Lattice-based molecular thermodynamic models generally used for polymer systems can be applied to describe the thermodynamic properties and phase behavior of IL systems. In our previous work, a new lattice-fluid equation of state (LF EoS) was developed and successfully applied to normal fluid systems (Xu et al., Fluid Phase Equilib. 2008, 265, 112.). In this work, this LF EoS is further extended to model the pVT properties and phase equilibria of IL systems. The molecular parameters of ILs in this EoS were determined by correlating the experimental pVT data of pure ILs. It is shown that the pVT behavior of IL mixtures can be fairly well predicted by these parameters. The vapor−liquid equilibria (VLE) of binary IL−solvent systems were calculated by using an adjustable binary parameter, κ12. For liquid−liquid equilibria (LLE) of binary IL systems, a parameter Cr describing the effect of the mixture composition on the chain-length parameter r is further used, and satisfactory correlation is obtained. The upper critical solution temperature (UCST) can be predicted successfully. Moreover, the EoS reproduces the solubility data for carbon dioxide (CO2) in various ILs covering a wide range of pressures (0−100 MPa), and it describes the global behavior of trifluoromethane (CHF3) and IL mixtures. The results reveal that the LF EoS is well-suited for the calculation or prediction of the thermodynamic properties of systems containing ILs. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9011722 Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11202–11210
Titre : Phase equilibria of mixtures containing glycol and n-alkane : experimental study of infinite dilution activity coefficients and modeling using the cubic-plus-association equation of state Type de document : texte imprimé Auteurs : Waheed Afzal, Auteur ; Martin P. Breil, Auteur ; Pascal Théveneau, Auteur Année de publication : 2010 Article en page(s) : pp. 11202–11210 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Infinite dilution activity coefficients n-alkanes Cubic-plus-association equation Résumé : In this work, we report the infinite dilution activity coefficients for four n-alkanes (n-pentane, n-hexane, n-heptane, and n-octane) in monoethylene glycol in the temperature range from 298 to 334 K and at atmospheric pressure. Experimental data were measured using a previously described inert gas stripping technique. The new experimental data are compared with the literature data whenever possible. The experimental infinite dilution activity coefficients of several alkanes from n-pentane to n-hexadecane in monoethylene glycol, diethylene glycol, triethylene glycol, and tetraethylene glycol previously reported in the literature, along with the data measured in this work have been modeled using the cubic-plus-association (CPA) equation of state (EoS). Satisfactory results have been obtained using temperature-independent interaction parameters. Useful remarks are presented about the application of infinite dilution activity coefficient data for estimating binary interaction parameters of the CPA EoS for the description of whole vapor−liquid equilibria. Furthermore, the variation in the values of the interaction parameters is discussed for different glycol systems. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900856q [article] Phase equilibria of mixtures containing glycol and n-alkane : experimental study of infinite dilution activity coefficients and modeling using the cubic-plus-association equation of state [texte imprimé] / Waheed Afzal, Auteur ; Martin P. Breil, Auteur ; Pascal Théveneau, Auteur . - 2010 . - pp. 11202–11210.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11202–11210
Mots-clés : Infinite dilution activity coefficients n-alkanes Cubic-plus-association equation Résumé : In this work, we report the infinite dilution activity coefficients for four n-alkanes (n-pentane, n-hexane, n-heptane, and n-octane) in monoethylene glycol in the temperature range from 298 to 334 K and at atmospheric pressure. Experimental data were measured using a previously described inert gas stripping technique. The new experimental data are compared with the literature data whenever possible. The experimental infinite dilution activity coefficients of several alkanes from n-pentane to n-hexadecane in monoethylene glycol, diethylene glycol, triethylene glycol, and tetraethylene glycol previously reported in the literature, along with the data measured in this work have been modeled using the cubic-plus-association (CPA) equation of state (EoS). Satisfactory results have been obtained using temperature-independent interaction parameters. Useful remarks are presented about the application of infinite dilution activity coefficient data for estimating binary interaction parameters of the CPA EoS for the description of whole vapor−liquid equilibria. Furthermore, the variation in the values of the interaction parameters is discussed for different glycol systems. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900856q Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11211–11219
Titre : Preparation and characterization of cellulose nanofibers from two commercial hardwood and softwood pulps Type de document : texte imprimé Auteurs : Wolfgang Stelte, Auteur ; Anand R. Sanadi, Auteur Année de publication : 2010 Article en page(s) : pp. 11211–11219 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Cellulose nanofibers Mechanical fibrillation process Microscopy techniques Résumé : The aim of this work was to study the mechanical fibrillation process for the preparation of cellulose nanofibers from two commercial hard- and softwood cellulose pulps. The process consisted of initial refining and subsequent high-pressure homogenization. The progress in fibrillation was studied using different microscopy techniques, mechanical testing, and fiber density measurements of cellulose films prepared after different processing stages. The mechanical properties of cellulose films showed an increase in strength and stiffness with decreasing fiber size, and this stabilized after a certain number of passes in the homogenizer. Atomic force microscopy studies showed that the obtained cellulose nanofibers had diameters in the 10−25-nm range. The significant difference between the two samples was that the ultimate failure strain for cellulose films made of softwood fibers increased during the process whereas it remained constantly low for hardwood cellulose films. This difference could be due to the presence of shorter fibers and more defects in the films. An important point to note is that excessive processing reduced properties, as seen by the decrease in failure strain of softwood fiber films, and could also decrease other properties such as strength if the number of processing steps were further increased. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9011672 [article] Preparation and characterization of cellulose nanofibers from two commercial hardwood and softwood pulps [texte imprimé] / Wolfgang Stelte, Auteur ; Anand R. Sanadi, Auteur . - 2010 . - pp. 11211–11219.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11211–11219
Mots-clés : Cellulose nanofibers Mechanical fibrillation process Microscopy techniques Résumé : The aim of this work was to study the mechanical fibrillation process for the preparation of cellulose nanofibers from two commercial hard- and softwood cellulose pulps. The process consisted of initial refining and subsequent high-pressure homogenization. The progress in fibrillation was studied using different microscopy techniques, mechanical testing, and fiber density measurements of cellulose films prepared after different processing stages. The mechanical properties of cellulose films showed an increase in strength and stiffness with decreasing fiber size, and this stabilized after a certain number of passes in the homogenizer. Atomic force microscopy studies showed that the obtained cellulose nanofibers had diameters in the 10−25-nm range. The significant difference between the two samples was that the ultimate failure strain for cellulose films made of softwood fibers increased during the process whereas it remained constantly low for hardwood cellulose films. This difference could be due to the presence of shorter fibers and more defects in the films. An important point to note is that excessive processing reduced properties, as seen by the decrease in failure strain of softwood fiber films, and could also decrease other properties such as strength if the number of processing steps were further increased. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9011672 Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11220–11224
Titre : Selective hydrogenation of maleic anhydride to tetrahydrofuran over Cu−Zn−M (M = Al, Ti, Zr) catalysts using ethanol as a solvent Type de document : texte imprimé Auteurs : Dongzhi Zhang, Auteur ; Hengbo Yin, Auteur ; Jinjuan Xue, Auteur Année de publication : 2010 Article en page(s) : pp. 11220–11224 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Cu− Zn− M catalysts Ethanol Résumé : A series of Cu−Zn−M (M = Al, Ti, Zr) catalysts were prepared by coprecipitation method and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and N2 adsorption. The catalytic activity of the Cu−Zn−M catalyst in maleic anhydride hydrogenation using ethanol as a solvent was studied at 220−280 °C and 1 MPa. The presence of MxOy in Cu−Zn−M (M = Al, Ti, Zr) catalysts favored the deep hydrogenation of maleic anhydride to tetrahydrofuran. The catalysts using TiO2 as a support showed the highest selectivity of tetrahydrofuran. The catalytic activity of the catalysts in the hydrogenation of maleic anhydride to tetrahydrofuran followed a sequence of Cu−Zn−Ti > Cu−Zn−Zr ≈ Cu−Zn−Al. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9013875 [article] Selective hydrogenation of maleic anhydride to tetrahydrofuran over Cu−Zn−M (M = Al, Ti, Zr) catalysts using ethanol as a solvent [texte imprimé] / Dongzhi Zhang, Auteur ; Hengbo Yin, Auteur ; Jinjuan Xue, Auteur . - 2010 . - pp. 11220–11224.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11220–11224
Mots-clés : Cu− Zn− M catalysts Ethanol Résumé : A series of Cu−Zn−M (M = Al, Ti, Zr) catalysts were prepared by coprecipitation method and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and N2 adsorption. The catalytic activity of the Cu−Zn−M catalyst in maleic anhydride hydrogenation using ethanol as a solvent was studied at 220−280 °C and 1 MPa. The presence of MxOy in Cu−Zn−M (M = Al, Ti, Zr) catalysts favored the deep hydrogenation of maleic anhydride to tetrahydrofuran. The catalysts using TiO2 as a support showed the highest selectivity of tetrahydrofuran. The catalytic activity of the catalysts in the hydrogenation of maleic anhydride to tetrahydrofuran followed a sequence of Cu−Zn−Ti > Cu−Zn−Zr ≈ Cu−Zn−Al. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9013875 Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11225–11229
Titre : Hydrodynamic characteristics of a sparged gas−liquid contactor for fine bubble generation Type de document : texte imprimé Auteurs : Chakraborty, D., Auteur ; G. Siva Rama Krishna, Auteur ; S. Chakraborty, Auteur Année de publication : 2010 Article en page(s) : pp. 11225–11229 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Gas− liquid bubble column Hydrodynamics Bubble generation Résumé : In this study, hydrodynamics of a gas−liquid bubble column with a following sparger made of ceramic, a perforated metal plate, brick material, and polypor porous material has been presented. Experiments were conducted for water levels of 100, 125, and 150 cm with and without the addition of frother. An attempt has been made to investigate the hydrodynamics of the downward flow of a high-pressure water jet at different jet heights and different water velocities. The column was operated with air at superficial gas velocities in the range of 0.122−3.7 cm/s. Effects of superficial gas velocity, frother doses, and jet height on gas holdup have been presented. Depending on experimental operating conditions for gas holdup, flow regimes were identified for different spargers. Experimental results shows that a ceramic type sparger has better gas holdup compared to other spargers. It was also found that gas holdup is greater with the addition of frother (70%) compared to that without addition of frother (20%). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901322e [article] Hydrodynamic characteristics of a sparged gas−liquid contactor for fine bubble generation [texte imprimé] / Chakraborty, D., Auteur ; G. Siva Rama Krishna, Auteur ; S. Chakraborty, Auteur . - 2010 . - pp. 11225–11229.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11225–11229
Mots-clés : Gas− liquid bubble column Hydrodynamics Bubble generation Résumé : In this study, hydrodynamics of a gas−liquid bubble column with a following sparger made of ceramic, a perforated metal plate, brick material, and polypor porous material has been presented. Experiments were conducted for water levels of 100, 125, and 150 cm with and without the addition of frother. An attempt has been made to investigate the hydrodynamics of the downward flow of a high-pressure water jet at different jet heights and different water velocities. The column was operated with air at superficial gas velocities in the range of 0.122−3.7 cm/s. Effects of superficial gas velocity, frother doses, and jet height on gas holdup have been presented. Depending on experimental operating conditions for gas holdup, flow regimes were identified for different spargers. Experimental results shows that a ceramic type sparger has better gas holdup compared to other spargers. It was also found that gas holdup is greater with the addition of frother (70%) compared to that without addition of frother (20%). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901322e Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11230–11235
Titre : Encapsulation of SiO2 and TiO2 fine powders with poly(dl-lactic-co-glycolic acid) by rapid expansion of supercritical CO2 incorporated with ethanol cosolvent Type de document : texte imprimé Auteurs : Benjapol Kongsombut, Auteur ; Atsushi Tsutsumi, Auteur ; Nara Suankaew, Auteur Année de publication : 2010 Article en page(s) : pp. 11230–11235 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Supercritical carbon dioxide solution Polymer shell Large SiO2 powders Résumé : Rapid expansion of supercritical carbon dioxide solution (RESS) for encapsulating core powders with a polymer shell was experimentally examined. Poly(dl-lactic-co-glycolic acid) polymer (PLGA) and 1.4-μm SiO2 as well as 70-nm TiO2 powders were employed as model encapsulating agent and core particles, respectively. A solution of PLGA in supercritical carbon dioxide (SC-CO2) was prepared incorporated with ethanol cosolvent. The RESS process was then performed by spraying the supercritical mixture through a capillary nozzle, leading to formation of well-dispersed PLGA nanoparticles. The precipitation of PLGA accompanying with its dispersion on core powder surface could be ascribed to the rigorous shear stress acting on the expanding flow of SC-CO2. The cumulative deposition of the precipitating PLGA could result in the uniform encapsulation of the SiO2 and TiO2 powders with 10 to 100 nm-thick PLGA layers in the form of both individual and agglomerating particles. The increased weight ratio of core particle to PLGA could lead to the more promoted encapsulation of core particles due to the higher contact among the core and precipitated PLGA particles after expansion. In comparison with large SiO2 powders, more rigorous agglomeration of encapsulated TiO2 powders would be attributed to their higher interparticle collections, which could also interfere with the expansion process. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900690v [article] Encapsulation of SiO2 and TiO2 fine powders with poly(dl-lactic-co-glycolic acid) by rapid expansion of supercritical CO2 incorporated with ethanol cosolvent [texte imprimé] / Benjapol Kongsombut, Auteur ; Atsushi Tsutsumi, Auteur ; Nara Suankaew, Auteur . - 2010 . - pp. 11230–11235.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11230–11235
Mots-clés : Supercritical carbon dioxide solution Polymer shell Large SiO2 powders Résumé : Rapid expansion of supercritical carbon dioxide solution (RESS) for encapsulating core powders with a polymer shell was experimentally examined. Poly(dl-lactic-co-glycolic acid) polymer (PLGA) and 1.4-μm SiO2 as well as 70-nm TiO2 powders were employed as model encapsulating agent and core particles, respectively. A solution of PLGA in supercritical carbon dioxide (SC-CO2) was prepared incorporated with ethanol cosolvent. The RESS process was then performed by spraying the supercritical mixture through a capillary nozzle, leading to formation of well-dispersed PLGA nanoparticles. The precipitation of PLGA accompanying with its dispersion on core powder surface could be ascribed to the rigorous shear stress acting on the expanding flow of SC-CO2. The cumulative deposition of the precipitating PLGA could result in the uniform encapsulation of the SiO2 and TiO2 powders with 10 to 100 nm-thick PLGA layers in the form of both individual and agglomerating particles. The increased weight ratio of core particle to PLGA could lead to the more promoted encapsulation of core particles due to the higher contact among the core and precipitated PLGA particles after expansion. In comparison with large SiO2 powders, more rigorous agglomeration of encapsulated TiO2 powders would be attributed to their higher interparticle collections, which could also interfere with the expansion process. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900690v Exemplaires
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inIndustrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11236–11240
Titre : Simple kinetic expressions to study the transport process during the growth of crystals in solution Type de document : texte imprimé Auteurs : K. Vasanth Kumar, Auteur Année de publication : 2010 Article en page(s) : pp. 11236–11240 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Kinetic expressions Crystals Burton− Cabrera− Frank model Résumé : First- and second-order kinetic expressions are proposed to explain the growth of crystals in solutions limited by diffusion and integration kinetics, respectively. The experimental growth kinetic data of sucrose crystals at 30 and 40 °C were fitted to the kinetic expressions by a linear regression method. A linear second-order expression proposed based on the Burton−Cabrera−Frank (BCF) model was found to be useful in identifying the transition in kinetics from the diffusion to the kinetic regime during the crystal growth process. A parameter, Atcritical (product of crystal area and time) was defined according to a second-order kinetic expression. The growth process was found to be limited by diffusion and surface reaction kinetics for At Atcritical, respectively. An initial reaction rate was defined according to a second-order surface reaction kinetics. The mass-transfer coefficient during the growth of crystals increases with increasing temperature, whereas the reaction kinetic constant was found to decrease with increasing temperature. The total adsorption energy for the growth of sucrose crystals in the diffusion and kinetic regime during was found to be >95 kJ/mol according to the derived expressions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900823x [article] Simple kinetic expressions to study the transport process during the growth of crystals in solution [texte imprimé] / K. Vasanth Kumar, Auteur . - 2010 . - pp. 11236–11240.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 11236–11240
Mots-clés : Kinetic expressions Crystals Burton− Cabrera− Frank model Résumé : First- and second-order kinetic expressions are proposed to explain the growth of crystals in solutions limited by diffusion and integration kinetics, respectively. The experimental growth kinetic data of sucrose crystals at 30 and 40 °C were fitted to the kinetic expressions by a linear regression method. A linear second-order expression proposed based on the Burton−Cabrera−Frank (BCF) model was found to be useful in identifying the transition in kinetics from the diffusion to the kinetic regime during the crystal growth process. A parameter, Atcritical (product of crystal area and time) was defined according to a second-order kinetic expression. The growth process was found to be limited by diffusion and surface reaction kinetics for At Atcritical, respectively. An initial reaction rate was defined according to a second-order surface reaction kinetics. The mass-transfer coefficient during the growth of crystals increases with increasing temperature, whereas the reaction kinetic constant was found to decrease with increasing temperature. The total adsorption energy for the growth of sucrose crystals in the diffusion and kinetic regime during was found to be >95 kJ/mol according to the derived expressions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900823x Exemplaires
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