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Vol. 49 N° 9 - Mai 2010 [texte imprimé] . - 2010 . - p. 3993-4474 : ill. ; 28 cm. Chemical engineering Langues : Français (fre)
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Ajouter le résultat dans votre panierPlanning and scheduling under uncertainty / Peter M. Verderame in Industrial & engineering chemistry research, Vol. 49 N° 9 (Mai 2010)
Titre : Planning and scheduling under uncertainty : A review across multiple sectors Type de document : texte imprimé Auteurs : Peter M. Verderame, Auteur ; Josephine A. Elia, Auteur ; Jie Li, Auteur Année de publication : 2010 Article en page(s) : pp. 3993–4017 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Uncertainty analysis Résumé : This paper provides an overview of the key contributions within the planning and scheduling communities with specific emphasis on uncertainty analysis. As opposed to focusing in one particular industry, several independent sectors have been reviewed in order to find commonalities and potential avenues for future interdisciplinary collaborations. The objectives and physical constraints present within the planning and scheduling problems may vary greatly from one sector to another; however, all problems share the common attribute of needing to model parameter uncertainty in an explicit manner. It will be demonstrated through the literature review that two-stage stochastic programming, parametric programming, fuzzy programming, chance constraint programming, robust optimization techniques, conditional value-at-risk, and other risk mitigation procedures have found widespread application within all of the analyzed sectors. This review is the first work which attempts to provide a comprehensive description of the advances and future directions for planning and scheduling under uncertainty within a variety of sectors. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902009k
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 3993–4017[article] Planning and scheduling under uncertainty : A review across multiple sectors [texte imprimé] / Peter M. Verderame, Auteur ; Josephine A. Elia, Auteur ; Jie Li, Auteur . - 2010 . - pp. 3993–4017.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 3993–4017
Mots-clés : Uncertainty analysis Résumé : This paper provides an overview of the key contributions within the planning and scheduling communities with specific emphasis on uncertainty analysis. As opposed to focusing in one particular industry, several independent sectors have been reviewed in order to find commonalities and potential avenues for future interdisciplinary collaborations. The objectives and physical constraints present within the planning and scheduling problems may vary greatly from one sector to another; however, all problems share the common attribute of needing to model parameter uncertainty in an explicit manner. It will be demonstrated through the literature review that two-stage stochastic programming, parametric programming, fuzzy programming, chance constraint programming, robust optimization techniques, conditional value-at-risk, and other risk mitigation procedures have found widespread application within all of the analyzed sectors. This review is the first work which attempts to provide a comprehensive description of the advances and future directions for planning and scheduling under uncertainty within a variety of sectors. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902009k Exemplaires
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Titre : Catalytic studies toward synthesis of 2,6 - dimethylnaphthalene from 1 - (p - Tolyl) - 2 - methylbutane Type de document : texte imprimé Auteurs : Kari Vahteristo, Auteur ; Kari-Matti Sahala, Auteur ; Salme Koskimies, Auteur Année de publication : 2010 Article en page(s) : pp. 4018–4025 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Catalysts Résumé : In this work experiments have been performed in order to study the synthesis of 2,6-dimethylnaphthalene (DMN) via dehydrocyclizing 1-(p-tolyl)-2-methylbutane over Pt/SiO2, V/Ca/Al2O3, and unimpregnated or potassium-impregnated Cr2O3/Al2O3 catalysts. The obtained liquid product mixture consisted of 1,6-cyclization products (dimethylnaphthalenes) and dealkylated 1,6-cyclization products (2-methylnaphthalene and naphthalene), 1,5-cyclization products (trimethylindanes and -indenes), and fragmentation products (mainly p-xylene and 3-(p-tolyl)-propylenes) and 1-(p-tolyl)-2-methylbutenes. Among 10 possible DMN isomers 1,5-, 1,6-, 2,6-, and 2,7-DMN were identified. Metal catalysts V/Ca/Al2O3 (5 wt % vanadium) and Pt/SiO2 (1 wt % platinum) were slightly more active than unimpregnated commercial Cr2O3/Al2O3. After 1 h on-stream time the conversion of 1-(p-tolyl)-2-methylbutane was 96 mol % when the artificial contact time (1/weight-hourly space velocity (WHSV)) was 5.7 h at 783 K over unimpregnated Cr2O3/Al2O3. Potassium impregnation decreased the conversion into 84 mol % because of the decreased Brunauer−Emmett−Teller surface area (from 97 m2/g unimpregnated to 70 m2/g potassium-impregnated catalyst). ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9008887
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4018–4025[article] Catalytic studies toward synthesis of 2,6 - dimethylnaphthalene from 1 - (p - Tolyl) - 2 - methylbutane [texte imprimé] / Kari Vahteristo, Auteur ; Kari-Matti Sahala, Auteur ; Salme Koskimies, Auteur . - 2010 . - pp. 4018–4025.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4018–4025
Mots-clés : Catalysts Résumé : In this work experiments have been performed in order to study the synthesis of 2,6-dimethylnaphthalene (DMN) via dehydrocyclizing 1-(p-tolyl)-2-methylbutane over Pt/SiO2, V/Ca/Al2O3, and unimpregnated or potassium-impregnated Cr2O3/Al2O3 catalysts. The obtained liquid product mixture consisted of 1,6-cyclization products (dimethylnaphthalenes) and dealkylated 1,6-cyclization products (2-methylnaphthalene and naphthalene), 1,5-cyclization products (trimethylindanes and -indenes), and fragmentation products (mainly p-xylene and 3-(p-tolyl)-propylenes) and 1-(p-tolyl)-2-methylbutenes. Among 10 possible DMN isomers 1,5-, 1,6-, 2,6-, and 2,7-DMN were identified. Metal catalysts V/Ca/Al2O3 (5 wt % vanadium) and Pt/SiO2 (1 wt % platinum) were slightly more active than unimpregnated commercial Cr2O3/Al2O3. After 1 h on-stream time the conversion of 1-(p-tolyl)-2-methylbutane was 96 mol % when the artificial contact time (1/weight-hourly space velocity (WHSV)) was 5.7 h at 783 K over unimpregnated Cr2O3/Al2O3. Potassium impregnation decreased the conversion into 84 mol % because of the decreased Brunauer−Emmett−Teller surface area (from 97 m2/g unimpregnated to 70 m2/g potassium-impregnated catalyst). ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9008887 Exemplaires
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Titre : Alternative method with amperometric detection for ranitidine determination Type de document : texte imprimé Auteurs : Valeria Pfaffen, Auteur ; Patricia Inés Ortiz, Auteur Année de publication : 2010 Article en page(s) : pp. 4026-4030 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Amperometric Detection Ranitidine Résumé : An alternative, simple, and reliable FIA amperometric method for ranitidine quantification was developed. A working glassy carbon electrode and a Ag|AgCl|NaCl (3 M) reference electrode were used. The determination is based on the electrochemical oxidation of ranitidine at 1.2 V in phosphate buffer solution (pH 7.2). The determination of ranitidine in the range of 1 × 10−6 to 2 × 10−5 M was possible with a sampling frequency of 120 h−1. The method was validated and satisfactorily applied to the determination of ranitidine in pharmaceutical formulations with a low limit of detection (6 × 10−7 M) and a quantitative recovery with no interferences from excipients. The results compare favorably with those obtained by the liquid chromatographic method of the U.S. Pharmacopoeia. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901895a
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4026-4030[article] Alternative method with amperometric detection for ranitidine determination [texte imprimé] / Valeria Pfaffen, Auteur ; Patricia Inés Ortiz, Auteur . - 2010 . - pp. 4026-4030.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4026-4030
Mots-clés : Amperometric Detection Ranitidine Résumé : An alternative, simple, and reliable FIA amperometric method for ranitidine quantification was developed. A working glassy carbon electrode and a Ag|AgCl|NaCl (3 M) reference electrode were used. The determination is based on the electrochemical oxidation of ranitidine at 1.2 V in phosphate buffer solution (pH 7.2). The determination of ranitidine in the range of 1 × 10−6 to 2 × 10−5 M was possible with a sampling frequency of 120 h−1. The method was validated and satisfactorily applied to the determination of ranitidine in pharmaceutical formulations with a low limit of detection (6 × 10−7 M) and a quantitative recovery with no interferences from excipients. The results compare favorably with those obtained by the liquid chromatographic method of the U.S. Pharmacopoeia. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901895a Exemplaires
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Titre : Large-Scale Synthesis of Double-Walled Carbon Nanotubes in Fluidized Beds Type de document : texte imprimé Auteurs : Oscar M. Dunens, Auteur ; Kieran J. MacKenzie, Auteur ; Andrew T. Harris, Auteur Année de publication : 2010 Article en page(s) : pp. 4031–4035 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Carbon Nanotubes Résumé : Double-walled carbon nanotubes (DWCNTs) are a unique allotrope of carbon with numerous potential applications including use in electronic and nanomechanical devices. However, existing methods and reaction conditions for DWCNT synthesis are inherently unscaleable, and production is limited to gram per hour quantities. Here, we report the synthesis of well-graphitized DWCNTs using fluidized bed chemical vapor deposition on an alumina-supported iron−molybdenum catalyst. Reaction products were analyzed using thermogravimetric analysis, Raman spectroscopy, and scanning and transmission electron microscopies. At a synthesis temperature of 850 °C and with use of methane as the carbon source, a 278% carbon yield relative to the weight of the metal catalyst was obtained. Carbon products consisted of approximately 75% DWCNTs with a good degree of wall graphitization (IG/ID = 4.85). The production technique and reaction conditions described here are capable of being applied at industrial scale. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100059q
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4031–4035[article] Large-Scale Synthesis of Double-Walled Carbon Nanotubes in Fluidized Beds [texte imprimé] / Oscar M. Dunens, Auteur ; Kieran J. MacKenzie, Auteur ; Andrew T. Harris, Auteur . - 2010 . - pp. 4031–4035.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4031–4035
Mots-clés : Carbon Nanotubes Résumé : Double-walled carbon nanotubes (DWCNTs) are a unique allotrope of carbon with numerous potential applications including use in electronic and nanomechanical devices. However, existing methods and reaction conditions for DWCNT synthesis are inherently unscaleable, and production is limited to gram per hour quantities. Here, we report the synthesis of well-graphitized DWCNTs using fluidized bed chemical vapor deposition on an alumina-supported iron−molybdenum catalyst. Reaction products were analyzed using thermogravimetric analysis, Raman spectroscopy, and scanning and transmission electron microscopies. At a synthesis temperature of 850 °C and with use of methane as the carbon source, a 278% carbon yield relative to the weight of the metal catalyst was obtained. Carbon products consisted of approximately 75% DWCNTs with a good degree of wall graphitization (IG/ID = 4.85). The production technique and reaction conditions described here are capable of being applied at industrial scale. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100059q Exemplaires
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Titre : Temperature zonal combustion reactor for the 15 - nitrogen and 13 - carbon isotopic determination of enriched biosynthetic materials Type de document : texte imprimé Auteurs : Michael May, Auteur ; John Kuo, Auteur ; Michael Gray, Auteur Année de publication : 2010 Article en page(s) : pp. 4036–4043 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Carbon Isotopic Résumé : A temperature distribution was imposed on a solid−gas reactor to help accomplish the 15-nitrogen or 13-carbon isotopic determination of biosynthetic materials such as algal protein-15N. The temperature zonal combustion reactor (TZCR) can operate offline from its mass spectrometer, and this reactor facilitates the stable isotopic determination of highly enriched biomaterials (>95 atom % isotope). The reactor structure is a glass pipe comprising a quartz segment, transition segments, and threaded sockets. Precise positioning of the reactor within a tubular furnace establishes a longitudinal temperature distribution that is used to drive solid−gas chemistry in distinct zones: sample, catalyst, and sorbent. The TZCR module typically includes a reactor pipe, gastight valve, sample, reactants, reactant containers, and furnace. An important advantage of TZCR-mass spectrometer is preliminary vacuum heat treatment of the crude sample to remove volatile impurities before sample combustion (enabling isotopic enrichment determination of the analyte). For the determination of 15N enrichment, sample combustion at 650 °C in oxygen was supplemented by Fe3O4 catalyst near 500 °C and Li2O at 25 °C that concertedly promoted the intrareactor depletion of CO, CO2, and H2O. As a result, the primary gaseous product was dinitrogen. After 15N sample conversion, the reactor was coupled to a quadrupole MS for product analysis (N2+ ions for 15N determination). Accordingly, uniformly enriched biomaterials were analyzed such as algal protein-15N that measured 99.0 ± 0.12 atom % 15N. By adapting the methodology for 13C determination, lyophilized algal cells-13C were determined to be 99.1 ± 0.06 atom % 13C. Stable isotope enrichments were computed by minimizing the numeric differences between theoretical and actual MS signals. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100072z
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4036–4043[article] Temperature zonal combustion reactor for the 15 - nitrogen and 13 - carbon isotopic determination of enriched biosynthetic materials [texte imprimé] / Michael May, Auteur ; John Kuo, Auteur ; Michael Gray, Auteur . - 2010 . - pp. 4036–4043.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4036–4043
Mots-clés : Carbon Isotopic Résumé : A temperature distribution was imposed on a solid−gas reactor to help accomplish the 15-nitrogen or 13-carbon isotopic determination of biosynthetic materials such as algal protein-15N. The temperature zonal combustion reactor (TZCR) can operate offline from its mass spectrometer, and this reactor facilitates the stable isotopic determination of highly enriched biomaterials (>95 atom % isotope). The reactor structure is a glass pipe comprising a quartz segment, transition segments, and threaded sockets. Precise positioning of the reactor within a tubular furnace establishes a longitudinal temperature distribution that is used to drive solid−gas chemistry in distinct zones: sample, catalyst, and sorbent. The TZCR module typically includes a reactor pipe, gastight valve, sample, reactants, reactant containers, and furnace. An important advantage of TZCR-mass spectrometer is preliminary vacuum heat treatment of the crude sample to remove volatile impurities before sample combustion (enabling isotopic enrichment determination of the analyte). For the determination of 15N enrichment, sample combustion at 650 °C in oxygen was supplemented by Fe3O4 catalyst near 500 °C and Li2O at 25 °C that concertedly promoted the intrareactor depletion of CO, CO2, and H2O. As a result, the primary gaseous product was dinitrogen. After 15N sample conversion, the reactor was coupled to a quadrupole MS for product analysis (N2+ ions for 15N determination). Accordingly, uniformly enriched biomaterials were analyzed such as algal protein-15N that measured 99.0 ± 0.12 atom % 15N. By adapting the methodology for 13C determination, lyophilized algal cells-13C were determined to be 99.1 ± 0.06 atom % 13C. Stable isotope enrichments were computed by minimizing the numeric differences between theoretical and actual MS signals. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100072z Exemplaires
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Titre : Effect of the synthesis method of MgAl2O4 and of Sn and Pb addition to platinum catalysts on the behavior in n - butane dehydrogenation Type de document : texte imprimé Auteurs : Sonia Bocanegra, Auteur ; Maria Julia Yanez, Auteur ; Osvaldo Scelza, Auteur Année de publication : 2010 Article en page(s) : pp. 4044-4054 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Dehydrogenation Catalyst Résumé : The MgAl2O4 spinels, synthesized by using two different methods (ceramic and coprecipitation), show very low acidity and good dispersion capacity of the metallic phase, these properties being suitable for the use of these materials as supports. However, MgAl2O4ccr displays higher strong acidity than MgAl2O4cop which seems to influence the metal—support interaction, since Pt/MgAl2O4cer catalyst shows higher metallic dispersion, lower metal particle sizes, and better catalytic behavior than the Pt/MgAl2O4cop one. The Sn addition to Pt/ MgAl2O4 improves the performance in the n-butane dehydrogenation process, increasing the activity, stability, and selectivity to butenes. This behavior is due to the presence of important Pt—Sn interactions, mainly in bimetallic catalysts supported on MgAl2O4cer. On the other hand, the Pb addition to monometallic catalysts does not enhance the catalytic performance in dehydrogenation. This behavior is in agreement with the characterization results of metallic phase that indicate important blocking effects in PtPb/MgAl2O4cer catalysts, and segregation effects in PtPb/MgAl2O4cop. In conclusion, the ceramic method of MgAl2O4 preparation provides the best support for PtSn catalysts in n-butane dehydrogenation reaction. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732893
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4044-4054[article] Effect of the synthesis method of MgAl2O4 and of Sn and Pb addition to platinum catalysts on the behavior in n - butane dehydrogenation [texte imprimé] / Sonia Bocanegra, Auteur ; Maria Julia Yanez, Auteur ; Osvaldo Scelza, Auteur . - 2010 . - pp. 4044-4054.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4044-4054
Mots-clés : Dehydrogenation Catalyst Résumé : The MgAl2O4 spinels, synthesized by using two different methods (ceramic and coprecipitation), show very low acidity and good dispersion capacity of the metallic phase, these properties being suitable for the use of these materials as supports. However, MgAl2O4ccr displays higher strong acidity than MgAl2O4cop which seems to influence the metal—support interaction, since Pt/MgAl2O4cer catalyst shows higher metallic dispersion, lower metal particle sizes, and better catalytic behavior than the Pt/MgAl2O4cop one. The Sn addition to Pt/ MgAl2O4 improves the performance in the n-butane dehydrogenation process, increasing the activity, stability, and selectivity to butenes. This behavior is due to the presence of important Pt—Sn interactions, mainly in bimetallic catalysts supported on MgAl2O4cer. On the other hand, the Pb addition to monometallic catalysts does not enhance the catalytic performance in dehydrogenation. This behavior is in agreement with the characterization results of metallic phase that indicate important blocking effects in PtPb/MgAl2O4cer catalysts, and segregation effects in PtPb/MgAl2O4cop. In conclusion, the ceramic method of MgAl2O4 preparation provides the best support for PtSn catalysts in n-butane dehydrogenation reaction. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732893 Exemplaires
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Titre : Char formation mechanism in supercritical water gasification process : a study of model compounds Type de document : texte imprimé Auteurs : Athika Chuntanapum, Auteur ; Yukihiko Matsumura, Auteur Année de publication : 2010 Article en page(s) : pp. 4055-4062 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Modeling Gasification Supercritical state Formation mechanism Résumé : Char is one of the undesirable products in the supercritical water gasification of biomass, causing a reduction in carbon gasification efficiency. 5-HMF (5-hydroxymethylfurfural) is believed to be an intermediate in the char formation pathway. In this Article, the rate of formation of char particles obtained from experiments using glucose (a biomass model compound) was compared to that from experiments using 5-HMF (Chuntanapum and Matsumura, 2009). The glucose experiments were conducted in a temperature range of 300—400 °C, at 25 MPa, and for a residence time up to 70 s. The initial concentration of glucose was varied from 1.5 to 3 wt % (i.e., 0.083 to 0.167 M). Glucose was found to produce char particles 2 orders of magnitude faster than 5-HMF feedstock. The copresence of the other glucose decomposition products is thought to cause the difference in the char formation mechanism (i.e., the side reaction between 5-HMF and the other decomposition products) from that of 5-HMF alone. FT-IR and Raman spectroscopy of the solid products was carried out. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732894
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4055-4062[article] Char formation mechanism in supercritical water gasification process : a study of model compounds [texte imprimé] / Athika Chuntanapum, Auteur ; Yukihiko Matsumura, Auteur . - 2010 . - pp. 4055-4062.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4055-4062
Mots-clés : Modeling Gasification Supercritical state Formation mechanism Résumé : Char is one of the undesirable products in the supercritical water gasification of biomass, causing a reduction in carbon gasification efficiency. 5-HMF (5-hydroxymethylfurfural) is believed to be an intermediate in the char formation pathway. In this Article, the rate of formation of char particles obtained from experiments using glucose (a biomass model compound) was compared to that from experiments using 5-HMF (Chuntanapum and Matsumura, 2009). The glucose experiments were conducted in a temperature range of 300—400 °C, at 25 MPa, and for a residence time up to 70 s. The initial concentration of glucose was varied from 1.5 to 3 wt % (i.e., 0.083 to 0.167 M). Glucose was found to produce char particles 2 orders of magnitude faster than 5-HMF feedstock. The copresence of the other glucose decomposition products is thought to cause the difference in the char formation mechanism (i.e., the side reaction between 5-HMF and the other decomposition products) from that of 5-HMF alone. FT-IR and Raman spectroscopy of the solid products was carried out. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732894 Exemplaires
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Titre : Preparation, characterization, and activity evaluation of H - ZSM - 5 catalysts in vapor - phase methanol dehydration to dimethyl ether Type de document : texte imprimé Auteurs : Samaneh Hassanpour, Auteur ; Majid Taghizadeh, Auteur Année de publication : 2010 Article en page(s) : pp. 4063-4069 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Dehydration Catalyst Preparation Résumé : Using the hydrothermal crystallization method, a highly crystalline series of H-ZSM-5 zeolites were prepared in different Si/Al molar ratios (ranging from 25 up to 250). The performance of prepared catalysts was a subject of assessment in the process of methanol dehydration to dimethyl ether (DME), where a stainless steel fixed-bed flow reactor at 573 K and 16 barg with WHSV of 26.5 h 1 was used. The catalysts were characterized by BET, XRD, NH3-TPD, ICP, TGA/DTA, TPH, and SEM techniques. According to the experimental results, the catalytic activity and surface acidity were increased with an increase in the Si/Al molar ratio up to 125 and then decreased. The sample with a Si/Al molar ratio of 125 [H-ZSM-5(125)] exhibited the best conversion and highest activity in methanol dehydration to DME. Before a comprehensive study was made on the synthesized zeolite catalysts, the dehydration reaction with crude methanol was studied over a commercial H-ZSM-5 catalyst under identical conditions. Results show that prepared catalysts have a better performance than commercial ones. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732895
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4063-4069[article] Preparation, characterization, and activity evaluation of H - ZSM - 5 catalysts in vapor - phase methanol dehydration to dimethyl ether [texte imprimé] / Samaneh Hassanpour, Auteur ; Majid Taghizadeh, Auteur . - 2010 . - pp. 4063-4069.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4063-4069
Mots-clés : Dehydration Catalyst Preparation Résumé : Using the hydrothermal crystallization method, a highly crystalline series of H-ZSM-5 zeolites were prepared in different Si/Al molar ratios (ranging from 25 up to 250). The performance of prepared catalysts was a subject of assessment in the process of methanol dehydration to dimethyl ether (DME), where a stainless steel fixed-bed flow reactor at 573 K and 16 barg with WHSV of 26.5 h 1 was used. The catalysts were characterized by BET, XRD, NH3-TPD, ICP, TGA/DTA, TPH, and SEM techniques. According to the experimental results, the catalytic activity and surface acidity were increased with an increase in the Si/Al molar ratio up to 125 and then decreased. The sample with a Si/Al molar ratio of 125 [H-ZSM-5(125)] exhibited the best conversion and highest activity in methanol dehydration to DME. Before a comprehensive study was made on the synthesized zeolite catalysts, the dehydration reaction with crude methanol was studied over a commercial H-ZSM-5 catalyst under identical conditions. Results show that prepared catalysts have a better performance than commercial ones. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732895 Exemplaires
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Titre : Numerical simulation of the gas − solid flow in fluidized - bed polymerization reactors Type de document : texte imprimé Auteurs : De-Pan Shi, Auteur ; Zheng-Hong Luo, Auteur ; An-Yi Guo, Auteur Année de publication : 2010 Article en page(s) : pp. 4070–4079 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Gas Solid Résumé : A three-dimensional computational fluid dynamics (CFD) model, using an Eulerian−Eulerian two-fluid model which incorporates the kinetic theory of granular flow, was developed to describe the gas−solid two-phase flow in fluidized-bed polymerization reactors. Corresponding simulations were carried out in a commercial CFD code Fluent. The entire flow field in the reactors was calculated by the model. The predicted pressure drop data were in agreement with the classical calculated data. In addition, the model was used to describe the solid holdup distributions, the bubble behaviors, and the solid velocity vectors in the free and agitated fluidized-bed polymerization reactors, respectively. The effects of the addition of an agitator on the gas−solid flow behaviors were preliminarily investigated via the model. The simulation results showed that the addition of an agitator can strengthen the fluidization efficiency and reduce the operation stability of the bed. However, the simulation results also showed that the total fluidization quality of the free fluidized bed was higher than that of the agitated fluidized bed at a superficial gas velocity of 0.5 m·s−1. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901424g
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4070–4079[article] Numerical simulation of the gas − solid flow in fluidized - bed polymerization reactors [texte imprimé] / De-Pan Shi, Auteur ; Zheng-Hong Luo, Auteur ; An-Yi Guo, Auteur . - 2010 . - pp. 4070–4079.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4070–4079
Mots-clés : Gas Solid Résumé : A three-dimensional computational fluid dynamics (CFD) model, using an Eulerian−Eulerian two-fluid model which incorporates the kinetic theory of granular flow, was developed to describe the gas−solid two-phase flow in fluidized-bed polymerization reactors. Corresponding simulations were carried out in a commercial CFD code Fluent. The entire flow field in the reactors was calculated by the model. The predicted pressure drop data were in agreement with the classical calculated data. In addition, the model was used to describe the solid holdup distributions, the bubble behaviors, and the solid velocity vectors in the free and agitated fluidized-bed polymerization reactors, respectively. The effects of the addition of an agitator on the gas−solid flow behaviors were preliminarily investigated via the model. The simulation results showed that the addition of an agitator can strengthen the fluidization efficiency and reduce the operation stability of the bed. However, the simulation results also showed that the total fluidization quality of the free fluidized bed was higher than that of the agitated fluidized bed at a superficial gas velocity of 0.5 m·s−1. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901424g Exemplaires
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Titre : Synthesis, characterization, and catalytic activity of phosphorus modified H - ZSM - 5 catalysts in selective ethanol dehydration Type de document : texte imprimé Auteurs : Kanaparthi Ramesh, Auteur ; Jie Chang, Auteur ; Yi-Fan Han, Auteur Année de publication : 2010 Article en page(s) : pp. 4080-4090 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Dehydration Catalyst activity Résumé : Phosphorus (P) modified H-ZSM-5 catalysts were prepared by wet impregnation method by varying P loadings from 0 to 7.43 wt % using phosphoric acid (H3PO4) as the P source. The catalysts were tested for ethanol dehydration in the temperature range of 523—723 K. The P-modified catalysts were found to be highly active and selective toward ethylene at 673 K and atmospheric pressure. In addition, the P-modified catalysts were found to be extremely stable more than 200 h without any sign of deactivation. However, the selectivity was found to be strongly dependent on several factors such as P content, reaction temperature, and space velocity (WHSV). The P-modified ZSM-5 catalysts were also found to be highly active for the dehydration of aqueous ethanol solutions (10 wt %) showing very high ethylene selectivity (above 98%) at significantly lower temperature 623 K. The catalysts were thoroughly characterized using various methods, including N2 physisorption, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric differential thermal analysis (TG-DTA), 1H, 27Al, and 31P magic angle spinning nuclear magnetic resonance (MAS NMR), and amonia temperature programmed desorption (NH3-TPD). 27Al MAS NMR spectra suggest that P addition facilitate the breaking of Si―O―Al bond that lead to a partial dealumination. NH3-TPD results indicate that total acidity as well as density of high strength acid sites were decreased with P loading. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732897
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4080-4090[article] Synthesis, characterization, and catalytic activity of phosphorus modified H - ZSM - 5 catalysts in selective ethanol dehydration [texte imprimé] / Kanaparthi Ramesh, Auteur ; Jie Chang, Auteur ; Yi-Fan Han, Auteur . - 2010 . - pp. 4080-4090.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4080-4090
Mots-clés : Dehydration Catalyst activity Résumé : Phosphorus (P) modified H-ZSM-5 catalysts were prepared by wet impregnation method by varying P loadings from 0 to 7.43 wt % using phosphoric acid (H3PO4) as the P source. The catalysts were tested for ethanol dehydration in the temperature range of 523—723 K. The P-modified catalysts were found to be highly active and selective toward ethylene at 673 K and atmospheric pressure. In addition, the P-modified catalysts were found to be extremely stable more than 200 h without any sign of deactivation. However, the selectivity was found to be strongly dependent on several factors such as P content, reaction temperature, and space velocity (WHSV). The P-modified ZSM-5 catalysts were also found to be highly active for the dehydration of aqueous ethanol solutions (10 wt %) showing very high ethylene selectivity (above 98%) at significantly lower temperature 623 K. The catalysts were thoroughly characterized using various methods, including N2 physisorption, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric differential thermal analysis (TG-DTA), 1H, 27Al, and 31P magic angle spinning nuclear magnetic resonance (MAS NMR), and amonia temperature programmed desorption (NH3-TPD). 27Al MAS NMR spectra suggest that P addition facilitate the breaking of Si―O―Al bond that lead to a partial dealumination. NH3-TPD results indicate that total acidity as well as density of high strength acid sites were decreased with P loading. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732897 Exemplaires
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Titre : Application of a combined catalyst and sorbent for steam reforming of methane Type de document : texte imprimé Auteurs : Karl O. Albrecht, Auteur ; Justinus A. Satrio, Auteur ; Brent H. Shanks, Auteur Année de publication : 2010 Article en page(s) : pp. 4091–4098 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Catalyst Methane Résumé : The performance of a combined catalyst and sorbent material designed for reforming hydrocarbons was evaluated by reacting methane with steam at different temperatures and pressures in a reactor packed with the material. The combined material was in the form of small spherical pellets comprised of a sorbent core of lime encased in a porous shell made largely of sintered alumina that supported a nickel catalyst. On the basis of previous research, two shell formulations were included in the study. One shell formulation contained a small quantity of CaO for strengthening of the shells, whereas the other contained a similar quantity of La2O3. Reaction testing of the combined catalyst and sorbent over a temperature range of 550−650 °C and a pressure range of 1.0−10.0 atm showed that pellets with either shell formulation were capable of producing H2 at or near thermodynamic equilibrium levels during a period when CO2 was being rapidly absorbed by the core material. Limited lifecycle testing of the combined catalyst and sorbent was also conducted at 650 °C and 1.0 atm over 10 cycles of H2 production and sorbent regeneration. A product stream with 98 mol % H2 (dry basis) was produced during the rapid CO2 absorption period of each cycle. However, the length of this period declined with each cycle. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901914c
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4091–4098[article] Application of a combined catalyst and sorbent for steam reforming of methane [texte imprimé] / Karl O. Albrecht, Auteur ; Justinus A. Satrio, Auteur ; Brent H. Shanks, Auteur . - 2010 . - pp. 4091–4098.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4091–4098
Mots-clés : Catalyst Methane Résumé : The performance of a combined catalyst and sorbent material designed for reforming hydrocarbons was evaluated by reacting methane with steam at different temperatures and pressures in a reactor packed with the material. The combined material was in the form of small spherical pellets comprised of a sorbent core of lime encased in a porous shell made largely of sintered alumina that supported a nickel catalyst. On the basis of previous research, two shell formulations were included in the study. One shell formulation contained a small quantity of CaO for strengthening of the shells, whereas the other contained a similar quantity of La2O3. Reaction testing of the combined catalyst and sorbent over a temperature range of 550−650 °C and a pressure range of 1.0−10.0 atm showed that pellets with either shell formulation were capable of producing H2 at or near thermodynamic equilibrium levels during a period when CO2 was being rapidly absorbed by the core material. Limited lifecycle testing of the combined catalyst and sorbent was also conducted at 650 °C and 1.0 atm over 10 cycles of H2 production and sorbent regeneration. A product stream with 98 mol % H2 (dry basis) was produced during the rapid CO2 absorption period of each cycle. However, the length of this period declined with each cycle. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901914c Exemplaires
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Titre : Reversible autocatalytic hydrolysis of alkyl formate : kinetic and reactor modeling Type de document : texte imprimé Auteurs : Olatunde Jogunola, Auteur ; Tapio Salmi, Auteur ; Kari Eranen, Auteur Année de publication : 2010 Article en page(s) : pp. 4099–4106 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Hydrolysis Kinetic Résumé : The kinetics and thermodynamics of alkyl formate hydrolysis in liquid phase were studied in a laboratory-scale autoclave at temperatures between 333 and 383 K using different molar ratios of the reactants. The process was found to exhibit an autocatalytic effect due to the acid formed. More so, the rate of neutral hydrolysis of ethyl formate is faster compared to methyl formate in the uncatalyzed reaction. However, the autocatalytic effect is more pronounced in methyl formate hydrolysis. In addition, the effect of adding a small amount of formic acid as an initial charge upon the equilibrium conversion and kinetics was investigated, and it was found that the addition improved the reaction rate by reducing the induction period but it suppressed slightly the equilibrium conversion. A kinetic model was proposed to explain these experimental trends, and the model agreed well with the experimental results. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902031d
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4099–4106[article] Reversible autocatalytic hydrolysis of alkyl formate : kinetic and reactor modeling [texte imprimé] / Olatunde Jogunola, Auteur ; Tapio Salmi, Auteur ; Kari Eranen, Auteur . - 2010 . - pp. 4099–4106.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4099–4106
Mots-clés : Hydrolysis Kinetic Résumé : The kinetics and thermodynamics of alkyl formate hydrolysis in liquid phase were studied in a laboratory-scale autoclave at temperatures between 333 and 383 K using different molar ratios of the reactants. The process was found to exhibit an autocatalytic effect due to the acid formed. More so, the rate of neutral hydrolysis of ethyl formate is faster compared to methyl formate in the uncatalyzed reaction. However, the autocatalytic effect is more pronounced in methyl formate hydrolysis. In addition, the effect of adding a small amount of formic acid as an initial charge upon the equilibrium conversion and kinetics was investigated, and it was found that the addition improved the reaction rate by reducing the induction period but it suppressed slightly the equilibrium conversion. A kinetic model was proposed to explain these experimental trends, and the model agreed well with the experimental results. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902031d Exemplaires
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Titre : Tuning of the activity and induction period of the polymerization of propylene oxide catalyzed by double metal cyanide complexes Bearing B - Alkoxy alcohols as complexing agents Type de document : texte imprimé Auteurs : Sang Hyun Lee, Auteur ; In Kyu Lee, Auteur ; Ju Young Ha, Auteur Année de publication : 2010 Article en page(s) : pp. 4107–4116 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Oxide Metal Résumé : For the development of commercially viable catalyst systems for the polymerization of propylene oxide (PO), a series of double metal cyanide (DMC) complexes have been developed by reacting aqueous zinc(II) chloride with aqueous potassium hexacyanocobaltate(III) in the presence of various complexing agents (CAs) such as 2-methoxyethanol, 2-ethoxyethanol, 2-propoxyethanol, 2-butoxyethanol (BE), 1-methoxypropan-2-ol, 1-ethoxypropan-2-ol, 1-propoxypropan-2-ol, and 1-butoxypropan-2-ol (BP) with different polarities and tert-butyl alcohol (tBuOH). The catalyst composition was estimated by combining elemental analysis with thermogravimertic analysis. The coordination of the CA can be identified by employing X-ray photoelectron spectroscopy, X-ray diffraction patterns, and infrared spectroscopy of the catalysts. Pursuing a catalyst system showing favorable polymerization behavior for commercial aspects of both catalytic activity and reaction control, the kinetics of PO polymerizations were investigated by using 4 and 8 L reactors equipped with pilot programmable logic controller systems. While a DMC catalyst bearing tBuOH as a CA showed a long induction period, it gave a very high overall rate of polymerization once activated, resulting in severe exothermic reactions that are hard to control. This problem could be successfully overcome by using the DMC catalysts bearing BE or BP as a CA. All polyether polyols were analyzed by measuring their unsaturation level, molecular weight, and distribution. All of the polyols produced featured a low level of unsaturation (0.014−0.024 mequiv g−1), moderate number-average molecular weights (900−3400), and very narrow polydispersities (1.04−1.19). ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000967
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4107–4116[article] Tuning of the activity and induction period of the polymerization of propylene oxide catalyzed by double metal cyanide complexes Bearing B - Alkoxy alcohols as complexing agents [texte imprimé] / Sang Hyun Lee, Auteur ; In Kyu Lee, Auteur ; Ju Young Ha, Auteur . - 2010 . - pp. 4107–4116.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4107–4116
Mots-clés : Oxide Metal Résumé : For the development of commercially viable catalyst systems for the polymerization of propylene oxide (PO), a series of double metal cyanide (DMC) complexes have been developed by reacting aqueous zinc(II) chloride with aqueous potassium hexacyanocobaltate(III) in the presence of various complexing agents (CAs) such as 2-methoxyethanol, 2-ethoxyethanol, 2-propoxyethanol, 2-butoxyethanol (BE), 1-methoxypropan-2-ol, 1-ethoxypropan-2-ol, 1-propoxypropan-2-ol, and 1-butoxypropan-2-ol (BP) with different polarities and tert-butyl alcohol (tBuOH). The catalyst composition was estimated by combining elemental analysis with thermogravimertic analysis. The coordination of the CA can be identified by employing X-ray photoelectron spectroscopy, X-ray diffraction patterns, and infrared spectroscopy of the catalysts. Pursuing a catalyst system showing favorable polymerization behavior for commercial aspects of both catalytic activity and reaction control, the kinetics of PO polymerizations were investigated by using 4 and 8 L reactors equipped with pilot programmable logic controller systems. While a DMC catalyst bearing tBuOH as a CA showed a long induction period, it gave a very high overall rate of polymerization once activated, resulting in severe exothermic reactions that are hard to control. This problem could be successfully overcome by using the DMC catalysts bearing BE or BP as a CA. All polyether polyols were analyzed by measuring their unsaturation level, molecular weight, and distribution. All of the polyols produced featured a low level of unsaturation (0.014−0.024 mequiv g−1), moderate number-average molecular weights (900−3400), and very narrow polydispersities (1.04−1.19). ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000967 Exemplaires
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Titre : Continuous - flow esterification of free fatty acids in a rotating packed bed Type de document : texte imprimé Auteurs : Yi-Hung Chen, Auteur ; Wang-Chi Lin, Auteur ; Cheng-Hsien Tsai, Auteur Année de publication : 2010 Article en page(s) : pp. 4117–4122 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Esterification Fatty Acid Résumé : The continuous-flow esterification of free fatty acids (FFAs) with methanol for the production of fatty acid methyl esters (FAMEs) using a rotating packed bed (RPB) is presented herein. The RPB, which provides a high centrifugal force and has an adjustable rotational speed, was employed as a novel esterification reactor. The following variables were investigated for their effects on the esterification efficiency: the methanol-FFA molar ratio, the estimated hydraulic retention time, the rotational speed of the packed bed, the reaction temperature, and the catalyst dosage. The conversion of the FFAs in the RPB system significantly depended on the experimental conditions, which influenced the residence time distribution, the esterification reaction rate, and the micromixing intensity. Due to its excellent micromixing characteristics, the RPB system exhibited good efficiency for the esterification reaction in continuous-flow operation. The RPB system achieved the conversion of the FFAs of 10.0−96.6% and the productivity of FAMEs of 0.042−1.20 mol/min. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100112s
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4117–4122[article] Continuous - flow esterification of free fatty acids in a rotating packed bed [texte imprimé] / Yi-Hung Chen, Auteur ; Wang-Chi Lin, Auteur ; Cheng-Hsien Tsai, Auteur . - 2010 . - pp. 4117–4122.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4117–4122
Mots-clés : Esterification Fatty Acid Résumé : The continuous-flow esterification of free fatty acids (FFAs) with methanol for the production of fatty acid methyl esters (FAMEs) using a rotating packed bed (RPB) is presented herein. The RPB, which provides a high centrifugal force and has an adjustable rotational speed, was employed as a novel esterification reactor. The following variables were investigated for their effects on the esterification efficiency: the methanol-FFA molar ratio, the estimated hydraulic retention time, the rotational speed of the packed bed, the reaction temperature, and the catalyst dosage. The conversion of the FFAs in the RPB system significantly depended on the experimental conditions, which influenced the residence time distribution, the esterification reaction rate, and the micromixing intensity. Due to its excellent micromixing characteristics, the RPB system exhibited good efficiency for the esterification reaction in continuous-flow operation. The RPB system achieved the conversion of the FFAs of 10.0−96.6% and the productivity of FAMEs of 0.042−1.20 mol/min. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100112s Exemplaires
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Titre : Electrochemical Degradation of Perchloroethylene in Aqueous Media : Influence of the Electrochemical Operational Variables in the Viability of the Process Type de document : texte imprimé Auteurs : Veronica Saez, Auteur ; Maria Deseada Esclapez, Auteur ; Ignacio Tudela, Auteur Année de publication : 2010 Article en page(s) : pp. 4123-4131 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Electrochemical Aqueous Media Résumé : An extensive study of the influence of the operational variables in the electrochemical degradation of perchloroethylene in water has been carried out using an electrochemical filter-press reactor. The influences of the initial concentration, volumetric flow, and electrode geometry and nature on the kinetics, degradation efficiency, and mechanism have been analyzed by determining the values of process performance parameters such as fractional conversion, degradation efficiency, mass balance error, and selectivity. The best results obtained were a fractional conversion higher than 85%, degradation efficiencies of 65%, selectivities close to 0.8, and energetic consumption around 3 kWh m−3 obtained with two-dimensional electrodes. Three-dimensional carbon electrodes did not provide a more competitive option. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732902
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4123-4131[article] Electrochemical Degradation of Perchloroethylene in Aqueous Media : Influence of the Electrochemical Operational Variables in the Viability of the Process [texte imprimé] / Veronica Saez, Auteur ; Maria Deseada Esclapez, Auteur ; Ignacio Tudela, Auteur . - 2010 . - pp. 4123-4131.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4123-4131
Mots-clés : Electrochemical Aqueous Media Résumé : An extensive study of the influence of the operational variables in the electrochemical degradation of perchloroethylene in water has been carried out using an electrochemical filter-press reactor. The influences of the initial concentration, volumetric flow, and electrode geometry and nature on the kinetics, degradation efficiency, and mechanism have been analyzed by determining the values of process performance parameters such as fractional conversion, degradation efficiency, mass balance error, and selectivity. The best results obtained were a fractional conversion higher than 85%, degradation efficiencies of 65%, selectivities close to 0.8, and energetic consumption around 3 kWh m−3 obtained with two-dimensional electrodes. Three-dimensional carbon electrodes did not provide a more competitive option. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732902 Exemplaires
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Titre : Synthesis and kinetics of highly energetic intermediates by micromixers : direct multistep synthesis of sodium nitrotetrazolate Type de document : texte imprimé Auteurs : Nikolay Zaborenko, Auteur ; Edward R. Murphy, Auteur ; Jason G. Kralj, Auteur Année de publication : 2010 Article en page(s) : pp. 4132–4139 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Kinetics Micromixers Résumé : A modular silicon micromixer is designed and fabricated for high-flow rapid mixing at a wide range of reaction conditions. The mixer operates by splitting two inlet flows into a large number of channels, interdigitating them, and constricting the laminated flow to create submicrometer diffusion lengths. Mixing is quantified using the Villermaux−Dushman method, with UV−vis detection of the photoactive species, and compared against a commercial micromixer. Micromixers and tubing are then used to perform a quantitative kinetic study of the direct two-step synthesis of sodium nitrotetrazolate (NaNT) by a Sandmeyer type reaction via a reactive diazonium intermediate. Orders of reactions and temperature dependence of both steps, as well as pH and ionic strength dependence of the second step, are evaluated. Successful production of 4.4 g/h of NaNT in solution is ultimately achieved in a compact footprint using the kinetic data, verifying the potential for scaling to typical production amounts. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100263p
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4132–4139[article] Synthesis and kinetics of highly energetic intermediates by micromixers : direct multistep synthesis of sodium nitrotetrazolate [texte imprimé] / Nikolay Zaborenko, Auteur ; Edward R. Murphy, Auteur ; Jason G. Kralj, Auteur . - 2010 . - pp. 4132–4139.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4132–4139
Mots-clés : Kinetics Micromixers Résumé : A modular silicon micromixer is designed and fabricated for high-flow rapid mixing at a wide range of reaction conditions. The mixer operates by splitting two inlet flows into a large number of channels, interdigitating them, and constricting the laminated flow to create submicrometer diffusion lengths. Mixing is quantified using the Villermaux−Dushman method, with UV−vis detection of the photoactive species, and compared against a commercial micromixer. Micromixers and tubing are then used to perform a quantitative kinetic study of the direct two-step synthesis of sodium nitrotetrazolate (NaNT) by a Sandmeyer type reaction via a reactive diazonium intermediate. Orders of reactions and temperature dependence of both steps, as well as pH and ionic strength dependence of the second step, are evaluated. Successful production of 4.4 g/h of NaNT in solution is ultimately achieved in a compact footprint using the kinetic data, verifying the potential for scaling to typical production amounts. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100263p Exemplaires
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Titre : Cobalt fischer − tropsch catalysts using nickel promoter as a rhenium substitute to suppress deactivation Type de document : texte imprimé Auteurs : Erling Rytter, Auteur ; Torild H. Skagseth, Auteur ; Sigrid Eri, Auteur Année de publication : 2010 Article en page(s) : pp. 4140–4148 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Catalysts Résumé : Catalysts with cobalt as the Fischer−Tropsch (FT) metal and nickel and/or rhenium as promoters on alumina of different pore sizes, a stabilized alumina, silica, or titania as supports were investigated for activity, selectivity, and deactivation up to 800 h of operation in a fixed-bed reactor. From the observed selectivities, there is no indication that nickel as a promoter with a loading up to 5 wt % influences the selectivities to higher hydrocarbons for low-temperature ( ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100308f
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4140–4148[article] Cobalt fischer − tropsch catalysts using nickel promoter as a rhenium substitute to suppress deactivation [texte imprimé] / Erling Rytter, Auteur ; Torild H. Skagseth, Auteur ; Sigrid Eri, Auteur . - 2010 . - pp. 4140–4148.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4140–4148
Mots-clés : Catalysts Résumé : Catalysts with cobalt as the Fischer−Tropsch (FT) metal and nickel and/or rhenium as promoters on alumina of different pore sizes, a stabilized alumina, silica, or titania as supports were investigated for activity, selectivity, and deactivation up to 800 h of operation in a fixed-bed reactor. From the observed selectivities, there is no indication that nickel as a promoter with a loading up to 5 wt % influences the selectivities to higher hydrocarbons for low-temperature ( ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100308f Exemplaires
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Titre : Kinetic study of H2 oxidation in the preferential oxidation of CO on a nanosized Au / CeO2 catalyst Type de document : texte imprimé Auteurs : Jing Xu, Auteur ; Ping Li, Auteur ; Xingfu Song, Auteur Année de publication : 2010 Article en page(s) : pp. 4149–4155 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Kinetic Oxidation Catalyst Résumé : Kinetic study of H2 oxidation in the preferential oxidation (PROX) of CO was implemented over a nanosize Au/CeO2 catalyst in a temperature range 313−353 K. The Langmuir−Hinshelwood mechanism was proposed to be mainly responsible for H2 oxidation, and CO oxidation can be accelerated by coadsorbed H at low temperatures. On the other hand, the water in the system has proved to suppress both CO and H2 oxidation by increasing the energy bars. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) of CO adsorption on the Au surface indicates that linear CO−Au bond can be weakened in the presence of H2; meanwhile, water can be a poison taking effects via the bonding of water and the lattice oxygen at the interface of Au/CeO2. The irreversible loss of activity during reaction may be caused by the reconstruction of Au particles, at least in part. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100325y
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4149–4155[article] Kinetic study of H2 oxidation in the preferential oxidation of CO on a nanosized Au / CeO2 catalyst [texte imprimé] / Jing Xu, Auteur ; Ping Li, Auteur ; Xingfu Song, Auteur . - 2010 . - pp. 4149–4155.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4149–4155
Mots-clés : Kinetic Oxidation Catalyst Résumé : Kinetic study of H2 oxidation in the preferential oxidation (PROX) of CO was implemented over a nanosize Au/CeO2 catalyst in a temperature range 313−353 K. The Langmuir−Hinshelwood mechanism was proposed to be mainly responsible for H2 oxidation, and CO oxidation can be accelerated by coadsorbed H at low temperatures. On the other hand, the water in the system has proved to suppress both CO and H2 oxidation by increasing the energy bars. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) of CO adsorption on the Au surface indicates that linear CO−Au bond can be weakened in the presence of H2; meanwhile, water can be a poison taking effects via the bonding of water and the lattice oxygen at the interface of Au/CeO2. The irreversible loss of activity during reaction may be caused by the reconstruction of Au particles, at least in part. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100325y Exemplaires
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Titre : Microfluidic fabrication of monodispersed pharmaceutical colloidal spheres of atorvastatin calcium with tunable sizes Type de document : texte imprimé Auteurs : Hai-Xia Zhang, Auteur ; Jie-Xin Wang, Auteur ; Lei Shao, Auteur Année de publication : 2010 Article en page(s) : pp. 4156–4161 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Microfluidic Résumé : In this work, monodispersed pharmaceutical colloidal spheres of atorvastatin calcium (AC) with tunable sizes have been synthesized in a microfluidic system at continuous flow conditions. The influences of the key parameters, including the concentration of the AC methanol solution, the overall flow rate, the flow rate of isopropanol, and the flow rate of the AC methanol solution on particle size and size distribution were discussed. The results indicated that the drug concentration and the flow rate could efficiently control the particle size and improve the polydispersity of the resulting particles. The particle size decreased from 760 to 300 nm with an increase in the AC concentration from 30 to 60 mg/mL and significantly increased from 430 to 2500 nm with an increase in the flow rate of the AC methanol solution from 2.7 to 16 mL/min. However, with the increase of the overall flow rate at a fixed flow ratio of 10, the particle size slightly decreased from 240 (10/1 mL/min) to 210 nm (30/3 mL/min) and then dramatically increased to 680 nm (80/8 mL/min). Also, the particle size first decreased and then increased with an increase in the flow rate of isopropanol. The prepared AC colloidal spheres were amorphous and displayed enhanced dissolution rate compared with the commercial AC. This work shows that the continuous synthesis in a microfluidic reactor is a simple and economic way to prepare monodispersed pharmaceutical colloidal particles or nanoparticles with tunable sizes. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901365w
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4156–4161[article] Microfluidic fabrication of monodispersed pharmaceutical colloidal spheres of atorvastatin calcium with tunable sizes [texte imprimé] / Hai-Xia Zhang, Auteur ; Jie-Xin Wang, Auteur ; Lei Shao, Auteur . - 2010 . - pp. 4156–4161.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4156–4161
Mots-clés : Microfluidic Résumé : In this work, monodispersed pharmaceutical colloidal spheres of atorvastatin calcium (AC) with tunable sizes have been synthesized in a microfluidic system at continuous flow conditions. The influences of the key parameters, including the concentration of the AC methanol solution, the overall flow rate, the flow rate of isopropanol, and the flow rate of the AC methanol solution on particle size and size distribution were discussed. The results indicated that the drug concentration and the flow rate could efficiently control the particle size and improve the polydispersity of the resulting particles. The particle size decreased from 760 to 300 nm with an increase in the AC concentration from 30 to 60 mg/mL and significantly increased from 430 to 2500 nm with an increase in the flow rate of the AC methanol solution from 2.7 to 16 mL/min. However, with the increase of the overall flow rate at a fixed flow ratio of 10, the particle size slightly decreased from 240 (10/1 mL/min) to 210 nm (30/3 mL/min) and then dramatically increased to 680 nm (80/8 mL/min). Also, the particle size first decreased and then increased with an increase in the flow rate of isopropanol. The prepared AC colloidal spheres were amorphous and displayed enhanced dissolution rate compared with the commercial AC. This work shows that the continuous synthesis in a microfluidic reactor is a simple and economic way to prepare monodispersed pharmaceutical colloidal particles or nanoparticles with tunable sizes. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901365w Exemplaires
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Titre : Preparation of monodispersed uniform silica spheres with large pore size for fast adsorption of proteins Type de document : texte imprimé Auteurs : Zheng Zhai, Auteur ; Yujun Wang, Auteur ; Yangcheng Lu, Auteur Année de publication : 2010 Article en page(s) : pp. 4162–4168 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Adsorption Pore size Preparation Résumé : In this paper, a “temperature-induced gelation” method, combined with microfluidic flows, has been developed to synthesize the uniform silica spheres with large pore structures for the fast adsorption of bovine serum albumin (BSA). The reversible-thermosentive property of methylcellulose (MC) and auxiliary function of poly(ethylene glycol) (PEG) were introduced to realize a fast gelation in a coaxial microfludic device. The effects of temperature and MC concentration on the gelation process were investigated by monitoring the change of viscosity of sol system over time. The silica spheres with different morphologies of internal structure were synthesized by adjusting the concentration of MC. The prepared silica spheres had large pore volumes (>2.0 mL/g) and an average mesopore diameter of >12 nm. Meanwhile, a large amount of macropores existed in the silica spheres. The bimodal mesopore-marcopore structure resulted in a high protein adsorption capacity (590 mg/g) and a fast adsorption rate (reaching equilibrium within 9 h). ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732907
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4162–4168[article] Preparation of monodispersed uniform silica spheres with large pore size for fast adsorption of proteins [texte imprimé] / Zheng Zhai, Auteur ; Yujun Wang, Auteur ; Yangcheng Lu, Auteur . - 2010 . - pp. 4162–4168.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4162–4168
Mots-clés : Adsorption Pore size Preparation Résumé : In this paper, a “temperature-induced gelation” method, combined with microfluidic flows, has been developed to synthesize the uniform silica spheres with large pore structures for the fast adsorption of bovine serum albumin (BSA). The reversible-thermosentive property of methylcellulose (MC) and auxiliary function of poly(ethylene glycol) (PEG) were introduced to realize a fast gelation in a coaxial microfludic device. The effects of temperature and MC concentration on the gelation process were investigated by monitoring the change of viscosity of sol system over time. The silica spheres with different morphologies of internal structure were synthesized by adjusting the concentration of MC. The prepared silica spheres had large pore volumes (>2.0 mL/g) and an average mesopore diameter of >12 nm. Meanwhile, a large amount of macropores existed in the silica spheres. The bimodal mesopore-marcopore structure resulted in a high protein adsorption capacity (590 mg/g) and a fast adsorption rate (reaching equilibrium within 9 h). ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732907 Exemplaires
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Titre : Microwave - assisted preparation of Mo2C/CNTs nanocomposites as efficient electrocatalyst supports for oxygen reduction reaction Type de document : texte imprimé Auteurs : Min Pang, Auteur ; Chuang Li, Auteur ; Ling Ding, Auteur Année de publication : 2010 Article en page(s) : pp. 4169-4174 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Nanocomposite Preparation Microwave Résumé : Nanostructured Mo2C/CNTs composites have been synthesized by using a novel methodology of microwave-assisted thermolytic molecular precursor with Mo(CO)6 as single source precursor. Pt electroeatalysts supported on the Mo2C/CNTs composites were prepared by using the modified ethylene glycol method. The resulting Mo2C/CNTs and Pt―Mo2C/CNTs were characterized by inductively coupled plasma-optical emission spectroscopy, thermogravimetric analysis, X-ray diffraction, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The rotating disk electrode experiments were used to measure electrocatalytic activity for oxygen reduction reaction. The results showed highly dispersed sphere-like Mo2C and Pt particles with 3—6 nm can be prepared upon CNTs by the above-mentioned methods. The formation process of Mo2C includes the following steps: decomposition of Mo(CO)6 precursor to the metallic Mo and CO, CO dismutation reaction, formation of the MoOxCy by the metallic Mo and CO, the MoOxCy carburization to Mo2C, and further carburization of Mo2C to Mo3C2. The Pt―Mo2C/CNTs sample gave higher electrochemical surface area and activity for oxygen reduction reaction with a more positive onset potential in acid solution than those of Pt/CNTs under the same condition, which was attributed to the synergistic effect among Pt, Mo2C, and CNTs. The findings indicate that Mo2C is an inexpensive and promising alternative to precious metal and worthy of further exploring for other applications in catalysis. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732908
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4169-4174[article] Microwave - assisted preparation of Mo2C/CNTs nanocomposites as efficient electrocatalyst supports for oxygen reduction reaction [texte imprimé] / Min Pang, Auteur ; Chuang Li, Auteur ; Ling Ding, Auteur . - 2010 . - pp. 4169-4174.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4169-4174
Mots-clés : Nanocomposite Preparation Microwave Résumé : Nanostructured Mo2C/CNTs composites have been synthesized by using a novel methodology of microwave-assisted thermolytic molecular precursor with Mo(CO)6 as single source precursor. Pt electroeatalysts supported on the Mo2C/CNTs composites were prepared by using the modified ethylene glycol method. The resulting Mo2C/CNTs and Pt―Mo2C/CNTs were characterized by inductively coupled plasma-optical emission spectroscopy, thermogravimetric analysis, X-ray diffraction, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The rotating disk electrode experiments were used to measure electrocatalytic activity for oxygen reduction reaction. The results showed highly dispersed sphere-like Mo2C and Pt particles with 3—6 nm can be prepared upon CNTs by the above-mentioned methods. The formation process of Mo2C includes the following steps: decomposition of Mo(CO)6 precursor to the metallic Mo and CO, CO dismutation reaction, formation of the MoOxCy by the metallic Mo and CO, the MoOxCy carburization to Mo2C, and further carburization of Mo2C to Mo3C2. The Pt―Mo2C/CNTs sample gave higher electrochemical surface area and activity for oxygen reduction reaction with a more positive onset potential in acid solution than those of Pt/CNTs under the same condition, which was attributed to the synergistic effect among Pt, Mo2C, and CNTs. The findings indicate that Mo2C is an inexpensive and promising alternative to precious metal and worthy of further exploring for other applications in catalysis. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732908 Exemplaires
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Titre : Synthesis of carbonaceous poly(furfuryl alcohol) membrane for water desalination Type de document : texte imprimé Auteurs : Li He, Auteur ; Li, Dan, Auteur ; Guangyou Zhang, Auteur Année de publication : 2010 Article en page(s) : pp. 4175–4180 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Water Desalination Résumé : A novel carbonaceous poly(furfuryl alcohol) (CPFA) membrane was fabricated by partially carbonizing a poly(furfuryl alcohol) (PFA) layer supported on a commercial polysulfone substrate with high-concentration sulfuric acid at room temperature. Gas permeation experiments suggested that the PFA membrane became microporous after sulfuric acid treatment. ATR-IR spectra showed that the furan structure of PFA was degraded by the high-concentration sulfuric acid, forming CPFA. As compared with the PFA membrane, the CPFA membrane exhibited significantly enhanced chlorine resistance and water desalination properties. The CPFA membrane had a salt rejection of around 93.3% and a water permeability of 1.54 L·μm·m−2·h−1·bar−1. After the chlorine treatment, the CPFA membrane exhibited a salt rejection of 73.7% and a water permeability of 2.01 L·μm·m−2·h−1·bar−1, whereas the PFA membrane had a salt rejection of only 60.1% and a water permeability of 0.17 L·μm·m−2·h−1·bar−1. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901886c
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4175–4180[article] Synthesis of carbonaceous poly(furfuryl alcohol) membrane for water desalination [texte imprimé] / Li He, Auteur ; Li, Dan, Auteur ; Guangyou Zhang, Auteur . - 2010 . - pp. 4175–4180.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4175–4180
Mots-clés : Water Desalination Résumé : A novel carbonaceous poly(furfuryl alcohol) (CPFA) membrane was fabricated by partially carbonizing a poly(furfuryl alcohol) (PFA) layer supported on a commercial polysulfone substrate with high-concentration sulfuric acid at room temperature. Gas permeation experiments suggested that the PFA membrane became microporous after sulfuric acid treatment. ATR-IR spectra showed that the furan structure of PFA was degraded by the high-concentration sulfuric acid, forming CPFA. As compared with the PFA membrane, the CPFA membrane exhibited significantly enhanced chlorine resistance and water desalination properties. The CPFA membrane had a salt rejection of around 93.3% and a water permeability of 1.54 L·μm·m−2·h−1·bar−1. After the chlorine treatment, the CPFA membrane exhibited a salt rejection of 73.7% and a water permeability of 2.01 L·μm·m−2·h−1·bar−1, whereas the PFA membrane had a salt rejection of only 60.1% and a water permeability of 0.17 L·μm·m−2·h−1·bar−1. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901886c Exemplaires
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Titre : Dynamic Water Transport in a Pigmented Porous Coating Medium : Novel Study of Droplet Absorption and Evaporation by Near-Infrared Spectroscopy Type de document : texte imprimé Auteurs : Carl-Mikael Tag, Auteur ; Mikko Juuti, Auteur ; Kimmo Koivunen, Auteur Année de publication : 2010 Article en page(s) : pp. 4181–4189 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Dynamic Porous Coating Résumé : The dynamic wetting of, and absorption into, model porous coatings in the form of compressed particulate pigment tablets by monocomponent, dual-component, and multicomponent liquid droplets has been studied by observation of apparent contact angle and near-infrared spectroscopy to identify the liquid water/moisture content. The absorption of the liquids was studied in a corresponding vapor-saturated environment. Liquid evaporation was determined for the tablets at both equilibrium starting pore saturation and under limited volume-filling conditions as evaporation proceeds. The changes in water and moisture content within the coatings as a function of time were also determined gravimetrically to relate the water uptake and evaporation being observed to changes in the near-infrared spectral data. Model and commercial offset printing fountain solutions were compared with respect to both absorption and evaporation. For the solutions containing isopropyl alcohol in water, a nonlinear behavior in the water response in the near-infrared spectra during absorption is observed as a function of time, which can be related to the fast evaporation of the alcohol. The nonlinear region was followed by a decline in water and moisture content as the penetration/evaporation of the water phase proceeded. Comparing the near-infrared water volume dependency in the upper layers of the structure with weight loss during evaporation showed that the mechanism of liquid transport to the surface−air interface reflected the logarithmic volume distribution of pore sizes, as might be expected from capillarity considerations and pore condensation hysteresis. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000289
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4181–4189[article] Dynamic Water Transport in a Pigmented Porous Coating Medium : Novel Study of Droplet Absorption and Evaporation by Near-Infrared Spectroscopy [texte imprimé] / Carl-Mikael Tag, Auteur ; Mikko Juuti, Auteur ; Kimmo Koivunen, Auteur . - 2010 . - pp. 4181–4189.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4181–4189
Mots-clés : Dynamic Porous Coating Résumé : The dynamic wetting of, and absorption into, model porous coatings in the form of compressed particulate pigment tablets by monocomponent, dual-component, and multicomponent liquid droplets has been studied by observation of apparent contact angle and near-infrared spectroscopy to identify the liquid water/moisture content. The absorption of the liquids was studied in a corresponding vapor-saturated environment. Liquid evaporation was determined for the tablets at both equilibrium starting pore saturation and under limited volume-filling conditions as evaporation proceeds. The changes in water and moisture content within the coatings as a function of time were also determined gravimetrically to relate the water uptake and evaporation being observed to changes in the near-infrared spectral data. Model and commercial offset printing fountain solutions were compared with respect to both absorption and evaporation. For the solutions containing isopropyl alcohol in water, a nonlinear behavior in the water response in the near-infrared spectra during absorption is observed as a function of time, which can be related to the fast evaporation of the alcohol. The nonlinear region was followed by a decline in water and moisture content as the penetration/evaporation of the water phase proceeded. Comparing the near-infrared water volume dependency in the upper layers of the structure with weight loss during evaporation showed that the mechanism of liquid transport to the surface−air interface reflected the logarithmic volume distribution of pore sizes, as might be expected from capillarity considerations and pore condensation hysteresis. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000289 Exemplaires
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Titre : Novel flame - retardant and antidripping branched polyesters prepared via phosphorus - containing ionic monomer as end - capping agent Type de document : texte imprimé Auteurs : Jun-Sheng Wang, Auteur ; Hai-Bo Zhao, Auteur ; Xin-Guo Ge, Auteur Année de publication : 2010 Article en page(s) : pp. 4190–4196 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Ionic Monomer Résumé : A series of novel branched polyester-based ionomers were synthesized with trihydroxy ethyl esters of trimethyl-1,3,5-benzentricarboxylate (as branching agent) and sodium salt of 2-hydroxyethyl 3-(phenylphosphinyl)propionate (SHPPP, as end-capping agent) by melt polycondensation. The chemical structures of the branched polyester-based ionomers were confirmed with 1H and 31P NMR spectra. The effects of branching and ionic end groups on the melt behavior and thermal properties were investigated by differential scanning calorimetry and thermogravimetric analysis. The flammability and fire behavior were characterized by limiting oxygen index (LOI) and cone calorimeter. The LOI values of branched poly(ethylene terephthalate)s (PETs) are higher than that of pure PET. The cone calorimeter parameters of the samples such as heat release rate, total heat release, and time to ignition indicate that the fire safety of branched polyester-based ionomers is improved by introducing SHPPP. The effects of SHPPP on accelerating char forming and antidripping could be observed clearly from the pictures of the samples after LOI test. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100057n
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4190–4196[article] Novel flame - retardant and antidripping branched polyesters prepared via phosphorus - containing ionic monomer as end - capping agent [texte imprimé] / Jun-Sheng Wang, Auteur ; Hai-Bo Zhao, Auteur ; Xin-Guo Ge, Auteur . - 2010 . - pp. 4190–4196.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4190–4196
Mots-clés : Ionic Monomer Résumé : A series of novel branched polyester-based ionomers were synthesized with trihydroxy ethyl esters of trimethyl-1,3,5-benzentricarboxylate (as branching agent) and sodium salt of 2-hydroxyethyl 3-(phenylphosphinyl)propionate (SHPPP, as end-capping agent) by melt polycondensation. The chemical structures of the branched polyester-based ionomers were confirmed with 1H and 31P NMR spectra. The effects of branching and ionic end groups on the melt behavior and thermal properties were investigated by differential scanning calorimetry and thermogravimetric analysis. The flammability and fire behavior were characterized by limiting oxygen index (LOI) and cone calorimeter. The LOI values of branched poly(ethylene terephthalate)s (PETs) are higher than that of pure PET. The cone calorimeter parameters of the samples such as heat release rate, total heat release, and time to ignition indicate that the fire safety of branched polyester-based ionomers is improved by introducing SHPPP. The effects of SHPPP on accelerating char forming and antidripping could be observed clearly from the pictures of the samples after LOI test. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100057n Exemplaires
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Titre : Prior checking and moving horizon smoothing for improved particle filtering Type de document : texte imprimé Auteurs : Lixin Lang, Auteur ; Prem K. Goel, Auteur ; Bhavik R. Bakshi, Auteur Année de publication : 2010 Article en page(s) : pp. 4197-4209 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Smoothing Surveillance Résumé : Particle filtering, also known as sequential Monte Carlo (SMC) sampling, has been successfully applied to general state-space models for Bayesian inference. Being a simulation method, its performance relies to some extent on the generated samples or particles. For a poor initial guess a large fraction of particles is usually less representative of the underlying state's distribution and could even cause SMC to diverge. In this paper, an intuitive statistic, predictive density is proposed to monitor the particles' performance. When below a statistically controlled threshold value, our approach triggers smoothing for obtaining a better estimate of the initial state in the case of a poor prior. We find that combining a moving horizon smoother with SMC is very effective for recovering from a poor prior and develop an integrated practical approach that combines these two powerful tools. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732912
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4197-4209[article] Prior checking and moving horizon smoothing for improved particle filtering [texte imprimé] / Lixin Lang, Auteur ; Prem K. Goel, Auteur ; Bhavik R. Bakshi, Auteur . - 2010 . - pp. 4197-4209.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4197-4209
Mots-clés : Smoothing Surveillance Résumé : Particle filtering, also known as sequential Monte Carlo (SMC) sampling, has been successfully applied to general state-space models for Bayesian inference. Being a simulation method, its performance relies to some extent on the generated samples or particles. For a poor initial guess a large fraction of particles is usually less representative of the underlying state's distribution and could even cause SMC to diverge. In this paper, an intuitive statistic, predictive density is proposed to monitor the particles' performance. When below a statistically controlled threshold value, our approach triggers smoothing for obtaining a better estimate of the initial state in the case of a poor prior. We find that combining a moving horizon smoother with SMC is very effective for recovering from a poor prior and develop an integrated practical approach that combines these two powerful tools. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732912 Exemplaires
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Titre : Diagnosis of poor control loop performance due to model − plant mismatch Type de document : texte imprimé Auteurs : S. Selvanathan, Auteur ; A. K. Tangirala, Auteur Année de publication : 2010 Article en page(s) : pp. 4210–4229 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Model plant mismatch Résumé : Model−plant mismatch is a crucial factor that influences the performance of a closed-loop system. A new approach is proposed for the diagnosis of poor control loop performance due to model−plant mismatch (MPM) in the internal model control framework. In particular, the objective is to identify the mismatch in specific components of a transfer function model, namely, the gain, time-constant, and delay from closed-loop operating data. A new quantity Gp/Gm, called the plant model ratio (PMR) in the frequency domain is introduced as a measure of model−plant mismatch. It is shown that there exists a unique signature in PMR for each combination of mismatch in model parameters, which is the key step in the proposed method. A method to estimate the PMR from closed-loop operating data is provided. Theoretical and practical aspects of the mapping between the type of MPM and the proposed PMR are presented. Simulation studies demonstrate the effectiveness of the proposed method. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900769v
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4210–4229[article] Diagnosis of poor control loop performance due to model − plant mismatch [texte imprimé] / S. Selvanathan, Auteur ; A. K. Tangirala, Auteur . - 2010 . - pp. 4210–4229.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4210–4229
Mots-clés : Model plant mismatch Résumé : Model−plant mismatch is a crucial factor that influences the performance of a closed-loop system. A new approach is proposed for the diagnosis of poor control loop performance due to model−plant mismatch (MPM) in the internal model control framework. In particular, the objective is to identify the mismatch in specific components of a transfer function model, namely, the gain, time-constant, and delay from closed-loop operating data. A new quantity Gp/Gm, called the plant model ratio (PMR) in the frequency domain is introduced as a measure of model−plant mismatch. It is shown that there exists a unique signature in PMR for each combination of mismatch in model parameters, which is the key step in the proposed method. A method to estimate the PMR from closed-loop operating data is provided. Theoretical and practical aspects of the mapping between the type of MPM and the proposed PMR are presented. Simulation studies demonstrate the effectiveness of the proposed method. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900769v Exemplaires
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Titre : Design and planning of sustainable industrial networks : application to a recovery network of residual products Type de document : texte imprimé Auteurs : Joaquim Duque, Auteur ; Ana Paula F. D. Barbosa-Povoa, Auteur ; Augusto Q. Novais, Auteur Année de publication : 2010 Article en page(s) : pp. 4230–4248 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Industrial Networks Résumé : The present work describes the integration of environmental impact/damage evaluation into an optimization model for management of industrial networks. The selected methodology of environmental evaluation, the Eco-indicator 99, is based on the life cycle impact assessment. Its implementation and suitability is studied with an emphasis being placed on the strengths and limits of the methodology. The final model, derived from the application of process system engineering methodologies, is described as a mixed-integer linear program, which, once solved, is able to suggest the optimal processing and transportation routes, while optimizing a given objective function that either meets the design and environmental constraints or minimizes the eco-indicator. Whenever the impacts/damages costs are quantifiable, the calculation may also contemplate the inclusion of the environmental costs into the economic function that evaluates the network characteristic data and costs. An example based on the implementation of an innovative network for the recovery of the sludge obtained from aluminum surface finishing plants is presented. This illustrates the importance of including environmental impact/damage methodologies, explores their possible uses and analyzes obtained results. It is also used to perform a multiobjective analysis through an approximation to the Pareto curve for an economic-environmental trade-off. This curve is obtained through the application of a ε-constraint method, by plotting a set of successive optimized solutions given by the maximization of an economic function that reflects the costs of disposal, processing, transport, and materials storage versus an impact indicator obtained from the environment pollutants emitted. This analysis is complemented with the minimization of the eco-indicator value (EI99), along with an estimate of the corresponding amount of sludge recovery. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900940h
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4230–4248[article] Design and planning of sustainable industrial networks : application to a recovery network of residual products [texte imprimé] / Joaquim Duque, Auteur ; Ana Paula F. D. Barbosa-Povoa, Auteur ; Augusto Q. Novais, Auteur . - 2010 . - pp. 4230–4248.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4230–4248
Mots-clés : Industrial Networks Résumé : The present work describes the integration of environmental impact/damage evaluation into an optimization model for management of industrial networks. The selected methodology of environmental evaluation, the Eco-indicator 99, is based on the life cycle impact assessment. Its implementation and suitability is studied with an emphasis being placed on the strengths and limits of the methodology. The final model, derived from the application of process system engineering methodologies, is described as a mixed-integer linear program, which, once solved, is able to suggest the optimal processing and transportation routes, while optimizing a given objective function that either meets the design and environmental constraints or minimizes the eco-indicator. Whenever the impacts/damages costs are quantifiable, the calculation may also contemplate the inclusion of the environmental costs into the economic function that evaluates the network characteristic data and costs. An example based on the implementation of an innovative network for the recovery of the sludge obtained from aluminum surface finishing plants is presented. This illustrates the importance of including environmental impact/damage methodologies, explores their possible uses and analyzes obtained results. It is also used to perform a multiobjective analysis through an approximation to the Pareto curve for an economic-environmental trade-off. This curve is obtained through the application of a ε-constraint method, by plotting a set of successive optimized solutions given by the maximization of an economic function that reflects the costs of disposal, processing, transport, and materials storage versus an impact indicator obtained from the environment pollutants emitted. This analysis is complemented with the minimization of the eco-indicator value (EI99), along with an estimate of the corresponding amount of sludge recovery. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900940h Exemplaires
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Titre : Petri - net based approach to configure online fault diagnosis systems for batch processes Type de document : texte imprimé Auteurs : Yi-Chung Chen, Auteur ; Ming-Li Yeh, Auteur ; Chia-Lun Hong, Auteur Année de publication : 2010 Article en page(s) : pp. 4249–4268 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Batch Processes Résumé : Online fault diagnosis is a task of critical importance for maintaining a high level of operational safety in many chemical plants. The Petri-net models are adopted in this work for describing the fault propagation behaviors in batch processes. A systematic method has been developed to synthesize a timed Petri-net hierarchically structured according to any given piping and instrumentation diagram (P&ID) and its operating procedure. On the basis of this model, a diagnoser can be constructed automatically with a computer program for online implementation. Computer algorithms have also been devised to place additional sensors and/or synthesize extra operation steps for the purpose of improving diagnostic performance. Several examples are presented in this paper to demonstrate the effectiveness and correctness of the proposed approach. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901410p
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4249–4268[article] Petri - net based approach to configure online fault diagnosis systems for batch processes [texte imprimé] / Yi-Chung Chen, Auteur ; Ming-Li Yeh, Auteur ; Chia-Lun Hong, Auteur . - 2010 . - pp. 4249–4268.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4249–4268
Mots-clés : Batch Processes Résumé : Online fault diagnosis is a task of critical importance for maintaining a high level of operational safety in many chemical plants. The Petri-net models are adopted in this work for describing the fault propagation behaviors in batch processes. A systematic method has been developed to synthesize a timed Petri-net hierarchically structured according to any given piping and instrumentation diagram (P&ID) and its operating procedure. On the basis of this model, a diagnoser can be constructed automatically with a computer program for online implementation. Computer algorithms have also been devised to place additional sensors and/or synthesize extra operation steps for the purpose of improving diagnostic performance. Several examples are presented in this paper to demonstrate the effectiveness and correctness of the proposed approach. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901410p Exemplaires
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Titre : Understanding the impact of operating pressure on process intensification in reactive distillation columns Type de document : texte imprimé Auteurs : Shaofeng Wang, Auteur ; Kejin Huang, Auteur ; Quanquan Lin, Auteur Année de publication : 2010 Article en page(s) : pp. 4269–4284 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Reactive distillation column Résumé : For a reactive distillation column involving reactions with high thermal effect, process intensification can be reinforced with the prudent adjustment of operating pressure within its feasible region bounded by the given hot and cold utilities. Three specific situations can be identified and should be dealt with cautiously during process synthesis and design. For a reactive distillation column involving reversible endothermic reactions, the enhancement of the operating pressure increases reactant conversion and reaction heat load, thus facilitating process intensification between the reaction operation and the separation operation involved. For a reactive distillation column involving equilibrium-limited exothermic reactions, the abatement of operating pressure increases reactant conversion and the reaction heat load, thus reinforcing process intensification between the reaction operation and the separation operation involved. For a reactive distillation column involving kinetically controlled exothermic reactions, the complicated relationship between operating pressure and reactant conversion and reaction heat load must be dealt with carefully, thus being likely to benefit process intensification between the reaction operation and the separation operation involved. Six hypothetical ideal and two real reactive distillation systems involving either equilibrium-limited or kinetically controlled reactions with high thermal effect are studied to evaluate the proposed philosophy. It has been found that with the appropriate selection of operating pressure, a considerable reduction of utility consumption can be secured beside a possible abatement in capital investment. These striking results evidence the strong necessity of deepening process intensification through the adjustment of operating pressure in the synthesis and design of reactive distillation columns involving reactions with high thermal effect. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100067z
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4269–4284[article] Understanding the impact of operating pressure on process intensification in reactive distillation columns [texte imprimé] / Shaofeng Wang, Auteur ; Kejin Huang, Auteur ; Quanquan Lin, Auteur . - 2010 . - pp. 4269–4284.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4269–4284
Mots-clés : Reactive distillation column Résumé : For a reactive distillation column involving reactions with high thermal effect, process intensification can be reinforced with the prudent adjustment of operating pressure within its feasible region bounded by the given hot and cold utilities. Three specific situations can be identified and should be dealt with cautiously during process synthesis and design. For a reactive distillation column involving reversible endothermic reactions, the enhancement of the operating pressure increases reactant conversion and reaction heat load, thus facilitating process intensification between the reaction operation and the separation operation involved. For a reactive distillation column involving equilibrium-limited exothermic reactions, the abatement of operating pressure increases reactant conversion and the reaction heat load, thus reinforcing process intensification between the reaction operation and the separation operation involved. For a reactive distillation column involving kinetically controlled exothermic reactions, the complicated relationship between operating pressure and reactant conversion and reaction heat load must be dealt with carefully, thus being likely to benefit process intensification between the reaction operation and the separation operation involved. Six hypothetical ideal and two real reactive distillation systems involving either equilibrium-limited or kinetically controlled reactions with high thermal effect are studied to evaluate the proposed philosophy. It has been found that with the appropriate selection of operating pressure, a considerable reduction of utility consumption can be secured beside a possible abatement in capital investment. These striking results evidence the strong necessity of deepening process intensification through the adjustment of operating pressure in the synthesis and design of reactive distillation columns involving reactions with high thermal effect. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100067z Exemplaires
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Titre : Safe - parking framework for fault - tolerant control of transport − reaction processes Type de document : texte imprimé Auteurs : Maaz Mahmood, Auteur ; Prashant Mhaskar, Auteur Année de publication : 2010 Article en page(s) : pp. 4285–4296 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Transport Reaction Processes Résumé : This work considers the problem of handling actuator faults in transport−reaction processes described by quasi-linear parabolic partial differential equations (PDEs) subject to input constraints. To this end, first, by exploiting the separation between the fast and slow eigenmodes of the parabolic spatial differential operator in combination with Galerkin’s method, a finite set of ordinary differential equations (ODEs) that captures the dominant dynamics of the PDE system are constructed. This finite ODE system is used to develop a Lyapunov-based model predictive controller which provides an explicit characterization of the set of initial conditions from where closed-loop stability of the parabolic PDE system is guaranteed. This control design is then subsequently used to develop a safe-parking framework for handling faults. In particular, faults which preclude the possibility of maintaining operation at the nominal equilibrium distribution, using the existing robust or reconfiguration-based fault-tolerant control approaches are considered. The key idea is to temporarily maintain the process at an appropriate “safe-park” distribution using the available depleted control action. This “safe-park” distribution is chosen to prevent onset of hazardous situations as well as to ensure smooth resumption of nominal operation upon fault repair. Utilizing the stability region characterization provided by the developed predictive controller, safe-park distributions from the safe-park candidates (equilibrium distributions subject to the remaining functioning and fail-safe values of the failed actuators) are chosen to preserve closed-loop stability upon fault repair. The proposed framework is illustrated on a diffusion−reaction process. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901295x
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4285–4296[article] Safe - parking framework for fault - tolerant control of transport − reaction processes [texte imprimé] / Maaz Mahmood, Auteur ; Prashant Mhaskar, Auteur . - 2010 . - pp. 4285–4296.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4285–4296
Mots-clés : Transport Reaction Processes Résumé : This work considers the problem of handling actuator faults in transport−reaction processes described by quasi-linear parabolic partial differential equations (PDEs) subject to input constraints. To this end, first, by exploiting the separation between the fast and slow eigenmodes of the parabolic spatial differential operator in combination with Galerkin’s method, a finite set of ordinary differential equations (ODEs) that captures the dominant dynamics of the PDE system are constructed. This finite ODE system is used to develop a Lyapunov-based model predictive controller which provides an explicit characterization of the set of initial conditions from where closed-loop stability of the parabolic PDE system is guaranteed. This control design is then subsequently used to develop a safe-parking framework for handling faults. In particular, faults which preclude the possibility of maintaining operation at the nominal equilibrium distribution, using the existing robust or reconfiguration-based fault-tolerant control approaches are considered. The key idea is to temporarily maintain the process at an appropriate “safe-park” distribution using the available depleted control action. This “safe-park” distribution is chosen to prevent onset of hazardous situations as well as to ensure smooth resumption of nominal operation upon fault repair. Utilizing the stability region characterization provided by the developed predictive controller, safe-park distributions from the safe-park candidates (equilibrium distributions subject to the remaining functioning and fail-safe values of the failed actuators) are chosen to preserve closed-loop stability upon fault repair. The proposed framework is illustrated on a diffusion−reaction process. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901295x Exemplaires
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Titre : Design and control of a reactive distillation column based on a nonlinear wave propagation theory : production of terephthalic acid Type de document : texte imprimé Auteurs : Bo-kyung Kim, Auteur ; Hwidong Hwang, Auteur ; Daesik Woo, Auteur Année de publication : 2010 Article en page(s) : pp.4297–4307 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Production Wave propagation Distillation with reaction Design Résumé : This paper is concerned with the design and control of a reactive distillation column for the synthesis of terephthalic acid (TPA) from dimethyl terephthalate (DMT). Both components are possible monomers for the production of fresh polyesters. The potential of reactive distillation for the hydrolysis of DMT was investigated, and the effects of the design parameters on the performances of the process were explored. A steady-state design and the dynamic behavior of the reactive distillation process were analyzed based on a nonlinear wave theory. Keeping the location of the column composition profile at the proper location was found to make the reaction zone active in the reactive distillation column, leading to a higher TPA yield. The proposed control scheme demonstrated excellent control of the reaction yield and product purity. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732918
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp.4297–4307[article] Design and control of a reactive distillation column based on a nonlinear wave propagation theory : production of terephthalic acid [texte imprimé] / Bo-kyung Kim, Auteur ; Hwidong Hwang, Auteur ; Daesik Woo, Auteur . - 2010 . - pp.4297–4307.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp.4297–4307
Mots-clés : Production Wave propagation Distillation with reaction Design Résumé : This paper is concerned with the design and control of a reactive distillation column for the synthesis of terephthalic acid (TPA) from dimethyl terephthalate (DMT). Both components are possible monomers for the production of fresh polyesters. The potential of reactive distillation for the hydrolysis of DMT was investigated, and the effects of the design parameters on the performances of the process were explored. A steady-state design and the dynamic behavior of the reactive distillation process were analyzed based on a nonlinear wave theory. Keeping the location of the column composition profile at the proper location was found to make the reaction zone active in the reactive distillation column, leading to a higher TPA yield. The proposed control scheme demonstrated excellent control of the reaction yield and product purity. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732918 Exemplaires
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Titre : Sequential approach to design batch distillation processes for homogeneous azeotropic systems Type de document : texte imprimé Auteurs : Vincentius Surya Kurnia Adi, Auteur ; Chuei-Tin Chang, Auteur Année de publication : 2010 Article en page(s) : pp. 4308–4328 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Azeotropic Systems Résumé : By addressing both flowsheeting and scheduling issues, a systematic approach is developed in this work to design batch azeotropic distillation processes for the homogeneous ternary and quaternary systems. The proposed design strategy is implemented sequentially in three stages. First, an integer program (IP) is formulated for producing the optimal structure of state-task network (STN). A nonlinear program (NLP) is then developed to generate the corresponding material-balance constraints. In the final step, a mixed integer linear programming (MILP) model and a mixed integer nonlinear programming (MINLP) model are constructed for stipulating the optimal short-term and cyclic schedules respectively. The conventional concept of event points is adopted to facilitate the continuous-time representation in these model formulations. The implementation procedure is illustrated with two example systems in this paper. Satisfactory process configurations and production schedules can both be produced in all the cases we have studied so far. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100101w
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4308–4328[article] Sequential approach to design batch distillation processes for homogeneous azeotropic systems [texte imprimé] / Vincentius Surya Kurnia Adi, Auteur ; Chuei-Tin Chang, Auteur . - 2010 . - pp. 4308–4328.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4308–4328
Mots-clés : Azeotropic Systems Résumé : By addressing both flowsheeting and scheduling issues, a systematic approach is developed in this work to design batch azeotropic distillation processes for the homogeneous ternary and quaternary systems. The proposed design strategy is implemented sequentially in three stages. First, an integer program (IP) is formulated for producing the optimal structure of state-task network (STN). A nonlinear program (NLP) is then developed to generate the corresponding material-balance constraints. In the final step, a mixed integer linear programming (MILP) model and a mixed integer nonlinear programming (MINLP) model are constructed for stipulating the optimal short-term and cyclic schedules respectively. The conventional concept of event points is adopted to facilitate the continuous-time representation in these model formulations. The implementation procedure is illustrated with two example systems in this paper. Satisfactory process configurations and production schedules can both be produced in all the cases we have studied so far. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100101w Exemplaires
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Titre : Optimization of preventive maintenance in chemical process plants Type de document : texte imprimé Auteurs : DuyQuang Nguyen, Auteur ; Miguel Bagajewicz, Auteur Année de publication : 2010 Article en page(s) : pp. 4329-4339 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Preventive maintenance Optimization Résumé : In this article, we use a genetic algorithm to obtain an economically optimal preventive maintenance frequency for different equipment, the parts inventory policy (number and type of spare parts to keep in stock), and labor allocation in process plants. To assess cost, we improved a previously published Monte Carlo simulation-based maintenance model (Nguyen et al. Ind. Eng. Chem. Res. 2008, 47(6), 1910−1924). Two examples, a Tennessee Eastman example and a fluid catalytic cracking unit in a refinery, are provided. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732920
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4329-4339[article] Optimization of preventive maintenance in chemical process plants [texte imprimé] / DuyQuang Nguyen, Auteur ; Miguel Bagajewicz, Auteur . - 2010 . - pp. 4329-4339.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4329-4339
Mots-clés : Preventive maintenance Optimization Résumé : In this article, we use a genetic algorithm to obtain an economically optimal preventive maintenance frequency for different equipment, the parts inventory policy (number and type of spare parts to keep in stock), and labor allocation in process plants. To assess cost, we improved a previously published Monte Carlo simulation-based maintenance model (Nguyen et al. Ind. Eng. Chem. Res. 2008, 47(6), 1910−1924). Two examples, a Tennessee Eastman example and a fluid catalytic cracking unit in a refinery, are provided. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732920 Exemplaires
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Titre : On the degeneracy of the water/wastewater allocation problem in process plants Type de document : texte imprimé Auteurs : Debora C. Faria, Auteur ; Miguel J. Bagajewicz, Auteur Année de publication : 2010 Article en page(s) : pp. 4340–4351 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Wastewater Process Plants Résumé : Several methodologies to design water systems in process plants are based on minimizing freshwater consumption. The objective is the appropriate one when water is scarce and costs are not a big issue. It has also been used as a substitute for cost in the belief that water and final treatment costs overwhelm other fixed capital and operating costs of regeneration processes. Among graphical and algorithmic methods, the popular “Pinch Technology”-based procedure has early proponents and contemporary advocates who consider and defend it as a good method to provide “insights” into the right answer. In this paper, we show that the minimum freshwater problem has sometimes a large number of alternative degenerate solutions, something that graphical and algorithmic procedures like the aforementioned pinch technology can hardly identify systematically. The fact that the degenerate solutions are many makes it worse. We provide a mathematical programming method to identify these solutions and to point out those that make more economical sense. We also provide means to identify suboptimal solutions that are very close to the optimum one. We illustrate these degeneracies in several cases of single and multiple contaminants. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901574g
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4340–4351[article] On the degeneracy of the water/wastewater allocation problem in process plants [texte imprimé] / Debora C. Faria, Auteur ; Miguel J. Bagajewicz, Auteur . - 2010 . - pp. 4340–4351.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4340–4351
Mots-clés : Wastewater Process Plants Résumé : Several methodologies to design water systems in process plants are based on minimizing freshwater consumption. The objective is the appropriate one when water is scarce and costs are not a big issue. It has also been used as a substitute for cost in the belief that water and final treatment costs overwhelm other fixed capital and operating costs of regeneration processes. Among graphical and algorithmic methods, the popular “Pinch Technology”-based procedure has early proponents and contemporary advocates who consider and defend it as a good method to provide “insights” into the right answer. In this paper, we show that the minimum freshwater problem has sometimes a large number of alternative degenerate solutions, something that graphical and algorithmic procedures like the aforementioned pinch technology can hardly identify systematically. The fact that the degenerate solutions are many makes it worse. We provide a mathematical programming method to identify these solutions and to point out those that make more economical sense. We also provide means to identify suboptimal solutions that are very close to the optimum one. We illustrate these degeneracies in several cases of single and multiple contaminants. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901574g Exemplaires
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Titre : Local modeling approach for spatially distributed system based on interval type - 2 T - S fuzzy sets Type de document : texte imprimé Auteurs : Mengling Wang, Auteur ; Ning Li, Auteur ; Shaoyuan Li, Auteur Année de publication : 2010 Article en page(s) : pp. 4352–4359 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Spatial dynamics Résumé : It is important to choose the appropriate type of local model to reduce the model error for a spatially distributed system (SDS) under large uncertainties. In this paper, a new local modeling approach is proposed to estimate the spatial dynamics of SDS based on input output data. The interval type-2 T-S fuzzy model is developed to the local dynamics in consideration of the mutual influence of neighbor regions. The parameters and the proper fuzzy rules of the local models are obtained by using interval type-2 fuzzy satisfactory clustering algorithm. Then the global models can be determined by constructing the local models by smooth interpolation. The accuracies of the modeling methodologies are tested in the shell and tube heat exchanger. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901278r
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4352–4359[article] Local modeling approach for spatially distributed system based on interval type - 2 T - S fuzzy sets [texte imprimé] / Mengling Wang, Auteur ; Ning Li, Auteur ; Shaoyuan Li, Auteur . - 2010 . - pp. 4352–4359.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4352–4359
Mots-clés : Spatial dynamics Résumé : It is important to choose the appropriate type of local model to reduce the model error for a spatially distributed system (SDS) under large uncertainties. In this paper, a new local modeling approach is proposed to estimate the spatial dynamics of SDS based on input output data. The interval type-2 T-S fuzzy model is developed to the local dynamics in consideration of the mutual influence of neighbor regions. The parameters and the proper fuzzy rules of the local models are obtained by using interval type-2 fuzzy satisfactory clustering algorithm. Then the global models can be determined by constructing the local models by smooth interpolation. The accuracies of the modeling methodologies are tested in the shell and tube heat exchanger. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901278r Exemplaires
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Titre : Dynamic simulation and optimization for the start - up operation of an ethylene oxide plant Type de document : texte imprimé Auteurs : Xiongtao Yang, Auteur ; Qiang Xu, Auteur ; Kuyen Li, Auteur Année de publication : 2010 Article en page(s) : pp. 4360–4371 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Ethylene Oxide Résumé : Ethylene oxide (EO) is an important chemical intermediate for the production of various chemical products. The manufacturing of EO involves critical exothermic reactions at high temperature and high pressure, whose failure may cause catastrophic personal injury, severe air pollution, and tremendous economic loss. Thus, an EO plant must be well controlled under various situations, especially during its start-up operations. In this paper, a general methodology for improving chemical plant start-up operations through plant-wide dynamic simulation has been developed. It undergoes modeling and validations for steady-state, dynamic, and historian start-up operations. On the basis of the validated dynamic simulation model, the original plant start-up strategy is further examined and optimized to speed-up the plant start-up operation with enhanced safety considerations. A case study on an EO plant start-up has demonstrated the significant operational and economic benefits of the proposed methodology. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9019038
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4360–4371[article] Dynamic simulation and optimization for the start - up operation of an ethylene oxide plant [texte imprimé] / Xiongtao Yang, Auteur ; Qiang Xu, Auteur ; Kuyen Li, Auteur . - 2010 . - pp. 4360–4371.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4360–4371
Mots-clés : Ethylene Oxide Résumé : Ethylene oxide (EO) is an important chemical intermediate for the production of various chemical products. The manufacturing of EO involves critical exothermic reactions at high temperature and high pressure, whose failure may cause catastrophic personal injury, severe air pollution, and tremendous economic loss. Thus, an EO plant must be well controlled under various situations, especially during its start-up operations. In this paper, a general methodology for improving chemical plant start-up operations through plant-wide dynamic simulation has been developed. It undergoes modeling and validations for steady-state, dynamic, and historian start-up operations. On the basis of the validated dynamic simulation model, the original plant start-up strategy is further examined and optimized to speed-up the plant start-up operation with enhanced safety considerations. A case study on an EO plant start-up has demonstrated the significant operational and economic benefits of the proposed methodology. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9019038 Exemplaires
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Titre : Desulfurization of low sulfur diesel by adsorption using activated carbon : adsorption isotherms Type de document : texte imprimé Auteurs : Celia Marin-Rosas, Auteur ; Luis F. Ramirez-Verduzco, Auteur ; Florentino R. Murrieta-Guevara, Auteur Année de publication : 2010 Article en page(s) : pp. 4372–4376 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Adsorption Carbon Isotherms Résumé : Adsorptive desulfurization was studied using diesel fuel with low sulfur content (72 ppmw) and four commercial activated carbons (CAA, CAB, CAC, and CAD). After the adsorption scheme, it was possible to obtain a diesel with 15 ppmw of sulfur content. The experiments were carried out in a batch system at 303.15 K, atmospheric pressure, and 5−200 g-A/L-D, with magnetic stirring over 18 h. The adsorption isotherms were correlated by the Freundlich, Langmuir, Sips and Brunauer−Emmett−Teller (BET) models. There was a good agreement between the experimental and calculated adsorption isotherms. The Sips and BET models give the best correlation for the experiment. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901756b
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4372–4376[article] Desulfurization of low sulfur diesel by adsorption using activated carbon : adsorption isotherms [texte imprimé] / Celia Marin-Rosas, Auteur ; Luis F. Ramirez-Verduzco, Auteur ; Florentino R. Murrieta-Guevara, Auteur . - 2010 . - pp. 4372–4376.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4372–4376
Mots-clés : Adsorption Carbon Isotherms Résumé : Adsorptive desulfurization was studied using diesel fuel with low sulfur content (72 ppmw) and four commercial activated carbons (CAA, CAB, CAC, and CAD). After the adsorption scheme, it was possible to obtain a diesel with 15 ppmw of sulfur content. The experiments were carried out in a batch system at 303.15 K, atmospheric pressure, and 5−200 g-A/L-D, with magnetic stirring over 18 h. The adsorption isotherms were correlated by the Freundlich, Langmuir, Sips and Brunauer−Emmett−Teller (BET) models. There was a good agreement between the experimental and calculated adsorption isotherms. The Sips and BET models give the best correlation for the experiment. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901756b Exemplaires
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Titre : Study on production of CH4 in hydrogen purification with palladium − silver / ceramic composite membranes Type de document : texte imprimé Auteurs : Yang Li, Auteur ; BingJia Yao, Auteur ; Tomonori Takahashi, Auteur Année de publication : 2010 Article en page(s) : pp. 4377–4382 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Hydrogen composite membranes Résumé : Hydrogen was purified by a series of Pd−Ag/ceramic composite membranes with different Pd−Ag alloy thickness ranging from 2.5 to 15 μm. During the process, methane (CH4) was found to be formed in the permeated gas, which was also reported in related studies. A comprehensive study was carried out to identify the source of CH4 by discussing the influence of membrane defect and feed composition with several gas mixtures as feed gas. It was found that CH4 content in the purified hydrogen increased with the defect degree, and for obtaining 99.9% permeated hydrogen, the helium leakage of the membrane should be less than 0.01 mL min−1 cm−2; whereas no helium flow should be detected, that is, the membranes should be completely defect-free, to achieve 99.999+% hydrogen. Meanwhile, different feed gases were used to discover the reason for production of CH4 during purification; the results revealed that only CO in the feed gas resulted in the formation of CH4 on the permeated side. Finally, on the basis of the above findings, a small amount of Au in the Pd−Ag alloy was added to examine the possibility of preventing CH4 formation, and the preliminary result was satisfactory. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900624v
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4377–4382[article] Study on production of CH4 in hydrogen purification with palladium − silver / ceramic composite membranes [texte imprimé] / Yang Li, Auteur ; BingJia Yao, Auteur ; Tomonori Takahashi, Auteur . - 2010 . - pp. 4377–4382.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4377–4382
Mots-clés : Hydrogen composite membranes Résumé : Hydrogen was purified by a series of Pd−Ag/ceramic composite membranes with different Pd−Ag alloy thickness ranging from 2.5 to 15 μm. During the process, methane (CH4) was found to be formed in the permeated gas, which was also reported in related studies. A comprehensive study was carried out to identify the source of CH4 by discussing the influence of membrane defect and feed composition with several gas mixtures as feed gas. It was found that CH4 content in the purified hydrogen increased with the defect degree, and for obtaining 99.9% permeated hydrogen, the helium leakage of the membrane should be less than 0.01 mL min−1 cm−2; whereas no helium flow should be detected, that is, the membranes should be completely defect-free, to achieve 99.999+% hydrogen. Meanwhile, different feed gases were used to discover the reason for production of CH4 during purification; the results revealed that only CO in the feed gas resulted in the formation of CH4 on the permeated side. Finally, on the basis of the above findings, a small amount of Au in the Pd−Ag alloy was added to examine the possibility of preventing CH4 formation, and the preliminary result was satisfactory. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900624v Exemplaires
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Titre : “Profile method” for the measurement of kLa and kVa in distillation columns. validation of rate - based distillation models using concentration profiles measured along the column Type de document : texte imprimé Auteurs : F. J. Rejl, Auteur ; L. Valenz, Auteur ; V. Linek, Auteur Année de publication : 2010 Article en page(s) : pp 4383–4398 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Distillation Columns Résumé : The “profile method” enables the determination of vapor- and liquid-side volumetric mass-transfer coefficients kVa and kLa by comparing the concentration profiles measured in both phases in a distillation column with the simulated profiles. The method is based on the fact that the shape of the concentration profiles along the column depend significantly on the distribution of the mass-transfer resistance between the liquid and vapor phases. This makes it possible to measure kLa and kVa directly in the distillation columns, in the same manner that is possible in absorption columns, and therefore to validate the distillation models more conclusively than by means of comparing the experimental and calculated height equivalent to a theoretical plate values. The coefficients were measured on structured packing Mellapak250Y. A small axial mixing of phases on this type of packing enables the use of a plug-flow model for both phases. Three distillation systems, methanol−ethanol, ethanol−propanol, and methanol−propanol, were used under total reflux and atmospheric pressure. Samples of the phases were withdrawn directly from the column packing by means of special sampling devices. The dependence of the individual transport coefficients on the phase flow rate was obtained by changing the reboiler duty. The dependencies were compared with those predicted by the following three mass-transfer correlations developed for packed columns: RBF (Rocha et al. Ind. Eng. Chem. Res. 1996, 35, 1660), BS (Billet, R.; Schultes, M. Trans. Inst. Chem. Eng. 1999, 77, 498), and DELFT (Olujic et al. Chem. Eng. Proc. 1999, 38, 683). The coefficients obtained by the profile method differ substantially from those calculated from the original models. Specifically, all of the original models considerably overvalue the kLa coefficients (RBF by up to 2 times, BS by up to 1.5 times, and DELFT by up to 6.3 times) and undervalue the kVa coefficients (all by up to 2 times). The dependence of the mass-transfer coefficients on the rate of the phases predicted by any of the original models is not consistent with that of the profile method. It has also been shown that the experimental concentration profiles strongly differ from the profiles calculated from the Aspen Plus simulation program. The correlations of the kLa and kVa coefficients with improved flow dependencies according to the profile method are presented. The concentration profiles calculated from the improved correlations fit the profiles accurately. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901690m
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp 4383–4398[article] “Profile method” for the measurement of kLa and kVa in distillation columns. validation of rate - based distillation models using concentration profiles measured along the column [texte imprimé] / F. J. Rejl, Auteur ; L. Valenz, Auteur ; V. Linek, Auteur . - 2010 . - pp 4383–4398.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp 4383–4398
Mots-clés : Distillation Columns Résumé : The “profile method” enables the determination of vapor- and liquid-side volumetric mass-transfer coefficients kVa and kLa by comparing the concentration profiles measured in both phases in a distillation column with the simulated profiles. The method is based on the fact that the shape of the concentration profiles along the column depend significantly on the distribution of the mass-transfer resistance between the liquid and vapor phases. This makes it possible to measure kLa and kVa directly in the distillation columns, in the same manner that is possible in absorption columns, and therefore to validate the distillation models more conclusively than by means of comparing the experimental and calculated height equivalent to a theoretical plate values. The coefficients were measured on structured packing Mellapak250Y. A small axial mixing of phases on this type of packing enables the use of a plug-flow model for both phases. Three distillation systems, methanol−ethanol, ethanol−propanol, and methanol−propanol, were used under total reflux and atmospheric pressure. Samples of the phases were withdrawn directly from the column packing by means of special sampling devices. The dependence of the individual transport coefficients on the phase flow rate was obtained by changing the reboiler duty. The dependencies were compared with those predicted by the following three mass-transfer correlations developed for packed columns: RBF (Rocha et al. Ind. Eng. Chem. Res. 1996, 35, 1660), BS (Billet, R.; Schultes, M. Trans. Inst. Chem. Eng. 1999, 77, 498), and DELFT (Olujic et al. Chem. Eng. Proc. 1999, 38, 683). The coefficients obtained by the profile method differ substantially from those calculated from the original models. Specifically, all of the original models considerably overvalue the kLa coefficients (RBF by up to 2 times, BS by up to 1.5 times, and DELFT by up to 6.3 times) and undervalue the kVa coefficients (all by up to 2 times). The dependence of the mass-transfer coefficients on the rate of the phases predicted by any of the original models is not consistent with that of the profile method. It has also been shown that the experimental concentration profiles strongly differ from the profiles calculated from the Aspen Plus simulation program. The correlations of the kLa and kVa coefficients with improved flow dependencies according to the profile method are presented. The concentration profiles calculated from the improved correlations fit the profiles accurately. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901690m Exemplaires
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Titre : High - Flux SAPO - 34 membrane for CO2 / N2 separation Type de document : texte imprimé Auteurs : Li, Shiguang, Auteur ; Chinbay Q. Fan, Auteur Année de publication : 2010 Article en page(s) : pp. 4399–4404 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Carbon dioxide Résumé : SAPO-34 membranes, synthesized by using multiple templates and reduced crystallization time, showed high CO2 permeability for separating CO2/N2 mixtures up to 230 °C. At a trans-membrane pressure drop of 138 kPa and an atmospheric pressure in the permeate side, one such membrane had a CO2 permeance of 1.2 × 10−6 mol/m2·s·Pa (= 3500 GPU) with a CO2/N2 separation selectivity of 32 for a 50/50 feed at 22 °C. At a feed pressure of 2.3 MPa (23 bar), the CO2 flux was as high as 75 kg/m2 h. The CO2/N2 separations were also investigated in part by using vacuum permeate pumping, where the membrane showed a CO2 permeance of 7.7 × 10−7 mol/m2·s·Pa and a CO2 permeate concentration of 93% for an equimolar feed at 22 °C. At 105 °C, adding 8% water vapor to the feed had almost no effect on the CO2/N2 separation selectivity. The CO2 permeance decreased by 37%, but it was recovered by calcination. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732927
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4399–4404[article] High - Flux SAPO - 34 membrane for CO2 / N2 separation [texte imprimé] / Li, Shiguang, Auteur ; Chinbay Q. Fan, Auteur . - 2010 . - pp. 4399–4404.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4399–4404
Mots-clés : Carbon dioxide Résumé : SAPO-34 membranes, synthesized by using multiple templates and reduced crystallization time, showed high CO2 permeability for separating CO2/N2 mixtures up to 230 °C. At a trans-membrane pressure drop of 138 kPa and an atmospheric pressure in the permeate side, one such membrane had a CO2 permeance of 1.2 × 10−6 mol/m2·s·Pa (= 3500 GPU) with a CO2/N2 separation selectivity of 32 for a 50/50 feed at 22 °C. At a feed pressure of 2.3 MPa (23 bar), the CO2 flux was as high as 75 kg/m2 h. The CO2/N2 separations were also investigated in part by using vacuum permeate pumping, where the membrane showed a CO2 permeance of 7.7 × 10−7 mol/m2·s·Pa and a CO2 permeate concentration of 93% for an equimolar feed at 22 °C. At 105 °C, adding 8% water vapor to the feed had almost no effect on the CO2/N2 separation selectivity. The CO2 permeance decreased by 37%, but it was recovered by calcination. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732927 Exemplaires
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Titre : Biosorption of lanthanum, cerium, europium, and ytterbium by a brown marine alga, turbinaria conoides Type de document : texte imprimé Auteurs : K. Vijayaraghavan, Auteur ; M. Sathishkumar, Auteur ; R. Balasubramanian, Auteur Année de publication : 2010 Article en page(s) : pp 4405–4411 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Biosorption Résumé : The ability of a brown marine alga, Turbinaria conoides, to remove four rare-earth elements (REEs; lanthanum, cerium, europium, and ytterbium) was evaluated. Results showed that T. conoides was an excellent biosorbent for all four REEs. The equilibrium pH was found to severely affect the biosorption performance; pH 4.9 ± 0.2 was found to be an optimum pH for favorable biosorption of REEs. The biosorption mechanism was found to proceed mainly by ion-exchange reactions between the lanthanide ions and the carboxyl groups present on the algal surface, confirmed by the pH edge, desorption, and scanning electron microscopy/energy-dispersive X-ray results. Biosorption isotherms were modeled using the Langmuir, Freundlich, and Toth isotherms, with the latter-described REE isotherms with very high correlation coefficients and lower error values. Maximum biosorption uptakes, according to the Langmuir model, were recorded as 154.7, 152.8, 138.2, and 121.2 mg/g for La, Ce, Eu, and Yb, respectively. Biosorption kinetics of REEs was found to be rapid, achieving 90% of total biosorption within 50 min. Desorption was successful with 0.05 M HCl, and the biomass was regenerated and reused for three sorption−desorption cycles without a significant loss in the biosorption capacity. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000373
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp 4405–4411[article] Biosorption of lanthanum, cerium, europium, and ytterbium by a brown marine alga, turbinaria conoides [texte imprimé] / K. Vijayaraghavan, Auteur ; M. Sathishkumar, Auteur ; R. Balasubramanian, Auteur . - 2010 . - pp 4405–4411.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp 4405–4411
Mots-clés : Biosorption Résumé : The ability of a brown marine alga, Turbinaria conoides, to remove four rare-earth elements (REEs; lanthanum, cerium, europium, and ytterbium) was evaluated. Results showed that T. conoides was an excellent biosorbent for all four REEs. The equilibrium pH was found to severely affect the biosorption performance; pH 4.9 ± 0.2 was found to be an optimum pH for favorable biosorption of REEs. The biosorption mechanism was found to proceed mainly by ion-exchange reactions between the lanthanide ions and the carboxyl groups present on the algal surface, confirmed by the pH edge, desorption, and scanning electron microscopy/energy-dispersive X-ray results. Biosorption isotherms were modeled using the Langmuir, Freundlich, and Toth isotherms, with the latter-described REE isotherms with very high correlation coefficients and lower error values. Maximum biosorption uptakes, according to the Langmuir model, were recorded as 154.7, 152.8, 138.2, and 121.2 mg/g for La, Ce, Eu, and Yb, respectively. Biosorption kinetics of REEs was found to be rapid, achieving 90% of total biosorption within 50 min. Desorption was successful with 0.05 M HCl, and the biomass was regenerated and reused for three sorption−desorption cycles without a significant loss in the biosorption capacity. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000373 Exemplaires
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Titre : Chemical equilibrium conversion of the tert - amyl - methyl - ether synthesis in the presence of n - pentane, tetrahydrofuran, or benzene Type de document : texte imprimé Auteurs : Vincent Liebert, Auteur ; Torben Hector, Auteur ; Jürgen Gmehling, Auteur Année de publication : 2010 Article en page(s) : pp. 4412-4419 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Chemical equilibrium Résumé : The chemical equilibrium conversion of the reversible liquid-phase etherification of isoamylene with methanol to tert-amyl-methyl-ether using Amberlyst 36 as catalyst was investigated in a temperature range from 312.15 to 354.15 K. The experiments were also carried out in the presence of n-pentane, tetrahydrofuran, or benzene to investigate the influence of different inert solvents on the equilibrium conversion. From the results the standard enthalpy and standard Gibbs energy of reaction have been determined. The experimental conversions have been compared with the predicted conversions assuming ideal and nonideal behavior. For the predictions, tabulated standard thermodynamic properties at 298.15 in the ideal gas state (ΔHf0, ΔGf0), vapor pressures Pis, and standard molar heat capacities cp0 in the liquid phase have been used. The required activity coefficients were calculated with the help of the Wilson model or predicted using the group-contribution method modified UNIFAC (Dortmund). ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732929
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4412-4419[article] Chemical equilibrium conversion of the tert - amyl - methyl - ether synthesis in the presence of n - pentane, tetrahydrofuran, or benzene [texte imprimé] / Vincent Liebert, Auteur ; Torben Hector, Auteur ; Jürgen Gmehling, Auteur . - 2010 . - pp. 4412-4419.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4412-4419
Mots-clés : Chemical equilibrium Résumé : The chemical equilibrium conversion of the reversible liquid-phase etherification of isoamylene with methanol to tert-amyl-methyl-ether using Amberlyst 36 as catalyst was investigated in a temperature range from 312.15 to 354.15 K. The experiments were also carried out in the presence of n-pentane, tetrahydrofuran, or benzene to investigate the influence of different inert solvents on the equilibrium conversion. From the results the standard enthalpy and standard Gibbs energy of reaction have been determined. The experimental conversions have been compared with the predicted conversions assuming ideal and nonideal behavior. For the predictions, tabulated standard thermodynamic properties at 298.15 in the ideal gas state (ΔHf0, ΔGf0), vapor pressures Pis, and standard molar heat capacities cp0 in the liquid phase have been used. The required activity coefficients were calculated with the help of the Wilson model or predicted using the group-contribution method modified UNIFAC (Dortmund). ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732929 Exemplaires
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Titre : Density prediction of ionic liquids at different temperatures and pressures using a group contribution equation of state based on electrolyte perturbation theory Type de document : texte imprimé Auteurs : Junfeng Wang, Auteur ; Zhibao Li, Auteur ; Chunxi Li, Auteur Année de publication : 2010 Article en page(s) : pp. 4420-4425 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Thermodynamic properties Perturbation theory Electrolyte Equations of state Ionic liquid Prediction Density Résumé : Based on the electrolyte perturbation theory, a group contribution equation of state that embodies hard-sphere repulsion, dispersive attraction, and ionic electrostatic interaction energy was established to calculate the density of ionic liquids (ILs). According to this method, each ionic liquid is divided into several groups representing cation, anion, and alkyl substituents. The performance of the model was examined by describing the densities of a large number of imidazolium-based ILs over a wide range of temperatures (293.15―414.15 K) and pressures (0.1-70.43 MPa). A total number of 202 data points of density for 12 ILs and 2 molecular liquids (i.e., I-methylimidazole and 1-ethylimidazole) were used to fit the group parameters, namely, the soft-core diameter σ and the dispersive energy e. The resulting group parameters were used to predict 961 data points of density for 29 ILs at varying temperatures and pressures. The model was found to estimate well the densities of ionic liquids with an overall average relative deviation (ARD) of 0.41% for correlation and an ARD of 0.63% for prediction, which demonstrates the applicability of the model and the rationality of the soft-core diameter and dispersive energy parameters. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732930
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4420-4425[article] Density prediction of ionic liquids at different temperatures and pressures using a group contribution equation of state based on electrolyte perturbation theory [texte imprimé] / Junfeng Wang, Auteur ; Zhibao Li, Auteur ; Chunxi Li, Auteur . - 2010 . - pp. 4420-4425.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4420-4425
Mots-clés : Thermodynamic properties Perturbation theory Electrolyte Equations of state Ionic liquid Prediction Density Résumé : Based on the electrolyte perturbation theory, a group contribution equation of state that embodies hard-sphere repulsion, dispersive attraction, and ionic electrostatic interaction energy was established to calculate the density of ionic liquids (ILs). According to this method, each ionic liquid is divided into several groups representing cation, anion, and alkyl substituents. The performance of the model was examined by describing the densities of a large number of imidazolium-based ILs over a wide range of temperatures (293.15―414.15 K) and pressures (0.1-70.43 MPa). A total number of 202 data points of density for 12 ILs and 2 molecular liquids (i.e., I-methylimidazole and 1-ethylimidazole) were used to fit the group parameters, namely, the soft-core diameter σ and the dispersive energy e. The resulting group parameters were used to predict 961 data points of density for 29 ILs at varying temperatures and pressures. The model was found to estimate well the densities of ionic liquids with an overall average relative deviation (ARD) of 0.41% for correlation and an ARD of 0.63% for prediction, which demonstrates the applicability of the model and the rationality of the soft-core diameter and dispersive energy parameters. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732930 Exemplaires
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Titre : Study of solid − liquid mixing in agitated tanks through computational fluid dynamics modeling Type de document : texte imprimé Auteurs : Seyed Hosseini, Auteur ; Dineshkumar Patel, Auteur ; Farhad Ein-Mozaffari, Auteur Année de publication : 2010 Article en page(s) : pp. 4426–4435 Note générale : Industrial chemisty Langues : Anglais (eng) Mots-clés : Fluid Dynamics Résumé : Solid−liquid mixing is one of the most important mixing operations due to its vast applications in many unit operations such as crystallization, adsorption, solid-catalyzed reaction, suspension polymerization, and activated sludge processes. In this study, a computational fluid dynamics (CFD) model was developed for solid−liquid mixing in a cylindrical tank equipped with a top-entering impeller to investigate the effect of impeller type (Lightnin A100, A200, and A310), impeller off-bottom clearance (T/6−T/2, where T is tank diameter), impeller speed (150−800 rpm), particle size (100−900 μm), and particle specific gravity (1.4−6) on the mixing quality. An Eulerian−Eulerian (EE) approach, standard k−ε model, and multiple reference frames (MRF) techniques were employed to simulate the two-phase flow, turbulent flow, and impeller rotation, respectively. The impeller torque, cloud height, and just suspended impeller speed (Njs) computed by the CFD model agreed well with the experimental data. The validated CFD model was then employed to calculate the solid concentration profiles by which the degree of homogeneity was quantified as a function of operating conditions and design parameters. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901130z
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4426–4435[article] Study of solid − liquid mixing in agitated tanks through computational fluid dynamics modeling [texte imprimé] / Seyed Hosseini, Auteur ; Dineshkumar Patel, Auteur ; Farhad Ein-Mozaffari, Auteur . - 2010 . - pp. 4426–4435.
Industrial chemisty
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4426–4435
Mots-clés : Fluid Dynamics Résumé : Solid−liquid mixing is one of the most important mixing operations due to its vast applications in many unit operations such as crystallization, adsorption, solid-catalyzed reaction, suspension polymerization, and activated sludge processes. In this study, a computational fluid dynamics (CFD) model was developed for solid−liquid mixing in a cylindrical tank equipped with a top-entering impeller to investigate the effect of impeller type (Lightnin A100, A200, and A310), impeller off-bottom clearance (T/6−T/2, where T is tank diameter), impeller speed (150−800 rpm), particle size (100−900 μm), and particle specific gravity (1.4−6) on the mixing quality. An Eulerian−Eulerian (EE) approach, standard k−ε model, and multiple reference frames (MRF) techniques were employed to simulate the two-phase flow, turbulent flow, and impeller rotation, respectively. The impeller torque, cloud height, and just suspended impeller speed (Njs) computed by the CFD model agreed well with the experimental data. The validated CFD model was then employed to calculate the solid concentration profiles by which the degree of homogeneity was quantified as a function of operating conditions and design parameters. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901130z Exemplaires
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Titre : Water cleaning of biodiesel. effect of catalyst concentration, water amount, and washing temperature on biodiesel obtained from rapeseed oil and used oil Type de document : texte imprimé Auteurs : Alberto Gonzalo, Auteur ; Manuel García, Auteur ; José Luis Sanchez, Auteur Année de publication : 2010 Article en page(s) : pp. 4436–4443 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Biodiesel Catalyst Résumé : The effect of changing the NaOH wt % (0.7−0.9%) in the transesterification, the amount of water (30−90 wt % of the biodiesel), and the temperature (40−60 °C) in the water cleaning step of biodiesel has been investigated, specifically the influence of these factors on some properties (acidity, viscosity and density) and contaminants (methanol, Na, glycerine, water, and glycerides) of the resulting biodiesel produced from two different oils (rapeseed and used frying oil) using a three factor-two level experimental design, and statistical analysis by ANOVA of the results. The biodiesels produced from both oils show very similar trends: methanol, sodium, and glycerine are almost completely removed from the biodiesel phase in one single step, whereas the glycerides content is not affected by the washing conditions. Viscosity and density are only very slightly affected by the washing step. The water content of the biodiesel is affected by both the water amount used and the temperature in an inverse way: the higher the temperature and the lower the water amount used in the cleaning step, the higher the water content in biodiesel. This washing step was also simulated in Aspen HYSYS V7.0 software. Using the NRTL thermodynamic package for properties calculation, the results obtained showed a reasonable agreement with experimental ones, although it should be improved for a better calculation of biodiesel final properties. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901707q
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4436–4443[article] Water cleaning of biodiesel. effect of catalyst concentration, water amount, and washing temperature on biodiesel obtained from rapeseed oil and used oil [texte imprimé] / Alberto Gonzalo, Auteur ; Manuel García, Auteur ; José Luis Sanchez, Auteur . - 2010 . - pp. 4436–4443.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4436–4443
Mots-clés : Biodiesel Catalyst Résumé : The effect of changing the NaOH wt % (0.7−0.9%) in the transesterification, the amount of water (30−90 wt % of the biodiesel), and the temperature (40−60 °C) in the water cleaning step of biodiesel has been investigated, specifically the influence of these factors on some properties (acidity, viscosity and density) and contaminants (methanol, Na, glycerine, water, and glycerides) of the resulting biodiesel produced from two different oils (rapeseed and used frying oil) using a three factor-two level experimental design, and statistical analysis by ANOVA of the results. The biodiesels produced from both oils show very similar trends: methanol, sodium, and glycerine are almost completely removed from the biodiesel phase in one single step, whereas the glycerides content is not affected by the washing conditions. Viscosity and density are only very slightly affected by the washing step. The water content of the biodiesel is affected by both the water amount used and the temperature in an inverse way: the higher the temperature and the lower the water amount used in the cleaning step, the higher the water content in biodiesel. This washing step was also simulated in Aspen HYSYS V7.0 software. Using the NRTL thermodynamic package for properties calculation, the results obtained showed a reasonable agreement with experimental ones, although it should be improved for a better calculation of biodiesel final properties. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901707q Exemplaires
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Titre : Performance of four axial flow impellers for agitation of pulp suspensions in a laboratory - scale cylindrical stock chest Type de document : texte imprimé Auteurs : Manish R. Bhole, Auteur ; Chad P. J. Bennington, Auteur Année de publication : 2010 Article en page(s) : pp. 4444–4451 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Axial flow Résumé : Axial flow impellers are commonly used for pulp suspension agitation. Pulp fiber suspensions are non-Newtonian and exhibit a yield stress. In mixing operations, a ‘cavern’ (region of active motion) is created around the impeller, with the size of the cavern affecting the quality of mixing attained. In this work, the cavern size produced by four different axial flow impellers in a Cm = 3% (mass concentration) hardwood pulp suspension was measured using electrical resistance tomography (ERT) and by analysis of dynamic mixing tests. Cavern size is shown to depend on impeller performance as characterized by power number, NP, and axial force number, Nf. At an equal power consumption of 0.53 kW/m3 the largest cavern was produced by the impeller having the largest values of NP and Nf. The measured cavern volumes compared well with predictions of the axial force model developed by Hui et al. [Hui, L. K.; Bennington, C. P. J.; Dumont, G. A. Cavern formation in pulp suspensions using side-entering axial-flow impellers. Chem. Eng. Sci. 2009, 64, 509], which accounted for interaction between the cavern and the vessel walls. When the cavern just filled the vessel volume, the time constants determined using the dynamic mixing test data reached 90% of their theoretical values (with the estimated standard deviation of ±10%), indicating that the chest approached an ideal dynamic response (complete mixing) with the onset of complete motion in the chest. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901854d
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4444–4451[article] Performance of four axial flow impellers for agitation of pulp suspensions in a laboratory - scale cylindrical stock chest [texte imprimé] / Manish R. Bhole, Auteur ; Chad P. J. Bennington, Auteur . - 2010 . - pp. 4444–4451.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4444–4451
Mots-clés : Axial flow Résumé : Axial flow impellers are commonly used for pulp suspension agitation. Pulp fiber suspensions are non-Newtonian and exhibit a yield stress. In mixing operations, a ‘cavern’ (region of active motion) is created around the impeller, with the size of the cavern affecting the quality of mixing attained. In this work, the cavern size produced by four different axial flow impellers in a Cm = 3% (mass concentration) hardwood pulp suspension was measured using electrical resistance tomography (ERT) and by analysis of dynamic mixing tests. Cavern size is shown to depend on impeller performance as characterized by power number, NP, and axial force number, Nf. At an equal power consumption of 0.53 kW/m3 the largest cavern was produced by the impeller having the largest values of NP and Nf. The measured cavern volumes compared well with predictions of the axial force model developed by Hui et al. [Hui, L. K.; Bennington, C. P. J.; Dumont, G. A. Cavern formation in pulp suspensions using side-entering axial-flow impellers. Chem. Eng. Sci. 2009, 64, 509], which accounted for interaction between the cavern and the vessel walls. When the cavern just filled the vessel volume, the time constants determined using the dynamic mixing test data reached 90% of their theoretical values (with the estimated standard deviation of ±10%), indicating that the chest approached an ideal dynamic response (complete mixing) with the onset of complete motion in the chest. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901854d Exemplaires
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