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Vol. 49 N° 13 - Juillet 2010 [texte imprimé] . - 2010 . - p. 5959-6260 : ill. ; 28 cm. Chemical engineering Langues : Français (fre)
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Ajouter le résultat dans votre panierCu - Zn - (Mn) - (Fe) - al layered double hydroxides and their mixed metal oxides / L. H. Zhang in Industrial & engineering chemistry research, Vol. 49 N° 13 (Juillet 2010)
Titre : Cu - Zn - (Mn) - (Fe) - al layered double hydroxides and their mixed metal oxides : physicochemical and catalytic properties in wet hydrogen peroxide oxidation of phenol Type de document : texte imprimé Auteurs : L. H. Zhang, Auteur ; F. Li, Auteur ; D. G. Evans, Auteur Année de publication : 2010 Article en page(s) : pp. 5959–5968 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Oxidation Hydrogen peroxide Catalytic reaction Résumé : Cu−Zn−Mn−Fe−Al layered double hydroxides (LDHs) with Cu/Zn/Mn/Fe/Al atomic ratios of 1/1/0/0/1, 1/1/1/0.3/0.7, and 1/0.7/0.3/0.3/0.7, respectively, in synthesis mixture were prepared by coprecipitation under controlled conditions of temperature and pH. The mixed oxides were obtained by decomposition of the precursors at 500 °C in air. The characterization has been performed by XRD, ICP-ES, FT-IR, TG−DTA, TG−DTA−MS, TEM, XPS,O2-TPD, and H2-TPR. The objective is to investigate the effects of Mn and Fe partial substitution into Cu−Zn−Al mixed metal oxide derived from LDH precursor on the physicochemical and catalytic properties. The results show that the Fe and Mn substitutions decrease the structural stability of LDHs and improve the redox behavior of calcined LDHs. The activity of catalytic wet hydrogen peroxide oxidation of phenol is proportional to the content of surface metal ions and mainly Cu2+ centers linked to the surface lattice oxygen, and the degree of the deep oxidation of it is mainly related to the reactivity of the weakly bonded surface oxygen, depending on the nature of the transition metal ions in the structure. The preoxidation of phenol by surface •OH radical originating from hydrogen peroxide favors the next deep oxidation. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22974410
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 5959–5968[article] Cu - Zn - (Mn) - (Fe) - al layered double hydroxides and their mixed metal oxides : physicochemical and catalytic properties in wet hydrogen peroxide oxidation of phenol [texte imprimé] / L. H. Zhang, Auteur ; F. Li, Auteur ; D. G. Evans, Auteur . - 2010 . - pp. 5959–5968.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 5959–5968
Mots-clés : Oxidation Hydrogen peroxide Catalytic reaction Résumé : Cu−Zn−Mn−Fe−Al layered double hydroxides (LDHs) with Cu/Zn/Mn/Fe/Al atomic ratios of 1/1/0/0/1, 1/1/1/0.3/0.7, and 1/0.7/0.3/0.3/0.7, respectively, in synthesis mixture were prepared by coprecipitation under controlled conditions of temperature and pH. The mixed oxides were obtained by decomposition of the precursors at 500 °C in air. The characterization has been performed by XRD, ICP-ES, FT-IR, TG−DTA, TG−DTA−MS, TEM, XPS,O2-TPD, and H2-TPR. The objective is to investigate the effects of Mn and Fe partial substitution into Cu−Zn−Al mixed metal oxide derived from LDH precursor on the physicochemical and catalytic properties. The results show that the Fe and Mn substitutions decrease the structural stability of LDHs and improve the redox behavior of calcined LDHs. The activity of catalytic wet hydrogen peroxide oxidation of phenol is proportional to the content of surface metal ions and mainly Cu2+ centers linked to the surface lattice oxygen, and the degree of the deep oxidation of it is mainly related to the reactivity of the weakly bonded surface oxygen, depending on the nature of the transition metal ions in the structure. The preoxidation of phenol by surface •OH radical originating from hydrogen peroxide favors the next deep oxidation. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22974410 Exemplaires
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Titre : Reductive modification of alkaline pulping of southern pine, integrated with hydrothermal pre - extraction of hemicelluloses Type de document : texte imprimé Auteurs : Sung-Hoon Yoon, Auteur ; Harry T. Cullinan, Auteur ; Gopal A. Krishnagopalan, Auteur Année de publication : 2010 Article en page(s) : pp. 5969–5976 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Alkaline Hydrothermal Résumé : This study was to investigate the effect of modification of the kraft cooking process integrated with hemicellulose pre-extraction on the properties of pulp produced from softwood chips. Loblolly pine wood chips were extracted with pressurized hot water at an elevated temperature and then subjected to conventional and modified kraft pulping. A reductive pretreatment using sodium borohydride (SBH) in a mild alkaline sodium sulfide solution was adopted for a modification of kraft pulping preceded by water extraction. The presence of SBH in pretreatment caused a pronounced increase in pulp yield of the water pre-extracted kraft pulps. This reductive modification strategy for water-extracted kraft pulping was evaluated in two different ways including double extraction (SBH-alkaline extraction preceded by water extraction) followed by AQ-kraft pulping (DE-AQKP) and water extraction followed by pretreated AQ-kraft pulping (WE-SB-AQKP). The DE-AQKP using 1% SBH showed the same pulp yield as normal kraft cooking at 12% water-extraction weight loss along with approximately 3% of additional sugar extracts from the second extraction stream. In the case of WE-SB-AQKP with 1% SBH, the same yield as the kraft control was achieved around 14% water-extraction weight loss. The SBH demand for zero-yield-loss in pretreatment was in proportion to water-extraction weight loss in kraft pulping preceded by water extraction. Pulps from the modified processes showed faster PFI mill refining responses than the corresponding kraft pulps. No significant changes in paper strength properties were observed in handsheets prepared from the modified kraft pulping preceded by water extraction except for some reductions in tear strength. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100005v
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 5969–5976[article] Reductive modification of alkaline pulping of southern pine, integrated with hydrothermal pre - extraction of hemicelluloses [texte imprimé] / Sung-Hoon Yoon, Auteur ; Harry T. Cullinan, Auteur ; Gopal A. Krishnagopalan, Auteur . - 2010 . - pp. 5969–5976.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 5969–5976
Mots-clés : Alkaline Hydrothermal Résumé : This study was to investigate the effect of modification of the kraft cooking process integrated with hemicellulose pre-extraction on the properties of pulp produced from softwood chips. Loblolly pine wood chips were extracted with pressurized hot water at an elevated temperature and then subjected to conventional and modified kraft pulping. A reductive pretreatment using sodium borohydride (SBH) in a mild alkaline sodium sulfide solution was adopted for a modification of kraft pulping preceded by water extraction. The presence of SBH in pretreatment caused a pronounced increase in pulp yield of the water pre-extracted kraft pulps. This reductive modification strategy for water-extracted kraft pulping was evaluated in two different ways including double extraction (SBH-alkaline extraction preceded by water extraction) followed by AQ-kraft pulping (DE-AQKP) and water extraction followed by pretreated AQ-kraft pulping (WE-SB-AQKP). The DE-AQKP using 1% SBH showed the same pulp yield as normal kraft cooking at 12% water-extraction weight loss along with approximately 3% of additional sugar extracts from the second extraction stream. In the case of WE-SB-AQKP with 1% SBH, the same yield as the kraft control was achieved around 14% water-extraction weight loss. The SBH demand for zero-yield-loss in pretreatment was in proportion to water-extraction weight loss in kraft pulping preceded by water extraction. Pulps from the modified processes showed faster PFI mill refining responses than the corresponding kraft pulps. No significant changes in paper strength properties were observed in handsheets prepared from the modified kraft pulping preceded by water extraction except for some reductions in tear strength. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100005v Exemplaires
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Titre : Gas chromatography mass spectrometric analysis of chemically derivatized hexahydrotriazine - based hydrogen sulfide scavengers : 1 Type de document : texte imprimé Auteurs : Grahame N. Taylor, Auteur ; Ron Matherly, Auteur Année de publication : 2010 Article en page(s) : pp. 5977-5980 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Hydrogen sulfides Gas chromatography Résumé : A gas chromatography-mass spectrometry method of assaying 1,3,5-tris(2-hydroxyethyl)hexahydro-s-triazine in laboratory and field fluids is presented. This method involves the tris-trifluoroacetylation of anhydrous 1,3,5-tris(2-hydroxyethyl)hexahydro-s-triazine to avoid the undesired thermolysis to oxazolidine. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22974412
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 5977-5980[article] Gas chromatography mass spectrometric analysis of chemically derivatized hexahydrotriazine - based hydrogen sulfide scavengers : 1 [texte imprimé] / Grahame N. Taylor, Auteur ; Ron Matherly, Auteur . - 2010 . - pp. 5977-5980.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 5977-5980
Mots-clés : Hydrogen sulfides Gas chromatography Résumé : A gas chromatography-mass spectrometry method of assaying 1,3,5-tris(2-hydroxyethyl)hexahydro-s-triazine in laboratory and field fluids is presented. This method involves the tris-trifluoroacetylation of anhydrous 1,3,5-tris(2-hydroxyethyl)hexahydro-s-triazine to avoid the undesired thermolysis to oxazolidine. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22974412 Exemplaires
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Titre : Optimization of green synthesis of potassium diformate and its potential as a mold Iinhibitor for animal feed Type de document : texte imprimé Auteurs : Wenshuang Lin, Auteur ; Huixuan Wang, Auteur ; Qingbiao Li, Auteur Année de publication : 2010 Article en page(s) : pp. 5981–5985 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Potassium diformate Résumé : Potassium diformate (KDF) has been regarded as an alternative to antibiotic growth promoters for animals. This paper delineates a 100% atom economical process for the preparation of KDF from formic acid and potassium formate. Parametric optimization of the synthesis was conducted with respect to reaction time, reaction temperature, and molar ratio of the reactants by employing orthogonal design of experiment method. The results manifested a molar ratio of HCOOH to HCOOK of 1.3, reaction temperature of 65 °C, and reaction time of 30 min as the optimal conditions with a KDF product yield of 94.0%. Efforts were also made to explore the antimold performance of KDF on animal feed using the plate count method. Compared with sodium diacetate (SDA), the widely used mold inhibitor, KDF exhibited even better antimold performance for animal feed. To our knowledge, this work first proved the applicability of KDF as a mold inhibitor for animal feed. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100332m
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 5981–5985[article] Optimization of green synthesis of potassium diformate and its potential as a mold Iinhibitor for animal feed [texte imprimé] / Wenshuang Lin, Auteur ; Huixuan Wang, Auteur ; Qingbiao Li, Auteur . - 2010 . - pp. 5981–5985.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 5981–5985
Mots-clés : Potassium diformate Résumé : Potassium diformate (KDF) has been regarded as an alternative to antibiotic growth promoters for animals. This paper delineates a 100% atom economical process for the preparation of KDF from formic acid and potassium formate. Parametric optimization of the synthesis was conducted with respect to reaction time, reaction temperature, and molar ratio of the reactants by employing orthogonal design of experiment method. The results manifested a molar ratio of HCOOH to HCOOK of 1.3, reaction temperature of 65 °C, and reaction time of 30 min as the optimal conditions with a KDF product yield of 94.0%. Efforts were also made to explore the antimold performance of KDF on animal feed using the plate count method. Compared with sodium diacetate (SDA), the widely used mold inhibitor, KDF exhibited even better antimold performance for animal feed. To our knowledge, this work first proved the applicability of KDF as a mold inhibitor for animal feed. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100332m Exemplaires
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Titre : Novel semibiobased copolyester containing poly (trimethylene - co - hexamethylene terephthalate) and poly (lactic acid) segments Type de document : texte imprimé Auteurs : Zhu Xiong, Auteur ; Jian-Bing Zeng, Auteur ; Xiu-Li Wang, Auteur Année de publication : 2010 Article en page(s) : pp. 5986–5992 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Polymer Acid Résumé : Poly (l-lactic acid) (PLLA) is a biobased polymer, and poly(trimethylene terephthalate) (PTT) is a semibiobased polymer. However, PLLA is biodegradable, and PTT is not. In this paper, their copolymers (PTHT−PLLA) are synthesized via chain-extension reaction of hydroxyl terminated poly(trimethylene-co-hexamethylene terephthalate) (PTHT−OH) and hydroxyl terminated poly(l-lactic acid) (PLLA−OH) using toluene-2,4-diisocyanate (TDI) as a chain extender. The structures and molecular weights of PTHT−OH, PLLA−OH, and PTHT−PLLA were characterized by Fourier transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance (1H NMR), and gel permeation chromatography (GPC). The thermal, crystalline, and mechanical properties of PTHT−PLLA were further studied by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), and tensile testing. The resulting PTHT−PLLA copolyesters went through a two-stage thermal decomposition behavior and showed two glass transition temperatures. The tensile testing results showed that PTHT−PLLA copolyesters have excellent flexibility with a strain of more than 300%, which is much higher than that of PLLA. The copolyesters are expected to have a better biodegradability than PTT. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100817h
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 5986–5992[article] Novel semibiobased copolyester containing poly (trimethylene - co - hexamethylene terephthalate) and poly (lactic acid) segments [texte imprimé] / Zhu Xiong, Auteur ; Jian-Bing Zeng, Auteur ; Xiu-Li Wang, Auteur . - 2010 . - pp. 5986–5992.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 5986–5992
Mots-clés : Polymer Acid Résumé : Poly (l-lactic acid) (PLLA) is a biobased polymer, and poly(trimethylene terephthalate) (PTT) is a semibiobased polymer. However, PLLA is biodegradable, and PTT is not. In this paper, their copolymers (PTHT−PLLA) are synthesized via chain-extension reaction of hydroxyl terminated poly(trimethylene-co-hexamethylene terephthalate) (PTHT−OH) and hydroxyl terminated poly(l-lactic acid) (PLLA−OH) using toluene-2,4-diisocyanate (TDI) as a chain extender. The structures and molecular weights of PTHT−OH, PLLA−OH, and PTHT−PLLA were characterized by Fourier transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance (1H NMR), and gel permeation chromatography (GPC). The thermal, crystalline, and mechanical properties of PTHT−PLLA were further studied by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), and tensile testing. The resulting PTHT−PLLA copolyesters went through a two-stage thermal decomposition behavior and showed two glass transition temperatures. The tensile testing results showed that PTHT−PLLA copolyesters have excellent flexibility with a strain of more than 300%, which is much higher than that of PLLA. The copolyesters are expected to have a better biodegradability than PTT. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100817h Exemplaires
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Titre : Catalytic effect of transition metal doped in the Li - N - H system for hydrogen storage : A first principle investigation Type de document : texte imprimé Auteurs : Qiang Wang, Auteur ; Zhiqian Chen, Auteur ; Yu, Wenbin, Auteur Année de publication : 2010 Article en page(s) : pp. 5993-5996 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Storage Catalytic reaction Résumé : The ternary Li—M—N—H systems, in which one of the Li sites in LiNH2 was substituted by transition metals (Ti, Cr, Fe, or Ni), were calculated with a first principle to explore new ternary systems for hydrogen storage. In order to evaluate their properties of hydrogen storage, the electronic structures, N—H chemical bonds, and thermodynamics of these systems were extensively computed and analyzed. In contrast to the Li—N—H system, these results proved a favorable energy cost to break the N-H bond and dissociate the H atom from these ternary amides. Of particular interest, there was a significant improvement in thermodynamics of the Li-Ti-N-H system, which had a reaction enthalpy of -46.6 kJ/mol compared with that of -75.67 kJ/mol in the Li—N—H system. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22974415
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 5993-5996[article] Catalytic effect of transition metal doped in the Li - N - H system for hydrogen storage : A first principle investigation [texte imprimé] / Qiang Wang, Auteur ; Zhiqian Chen, Auteur ; Yu, Wenbin, Auteur . - 2010 . - pp. 5993-5996.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 5993-5996
Mots-clés : Storage Catalytic reaction Résumé : The ternary Li—M—N—H systems, in which one of the Li sites in LiNH2 was substituted by transition metals (Ti, Cr, Fe, or Ni), were calculated with a first principle to explore new ternary systems for hydrogen storage. In order to evaluate their properties of hydrogen storage, the electronic structures, N—H chemical bonds, and thermodynamics of these systems were extensively computed and analyzed. In contrast to the Li—N—H system, these results proved a favorable energy cost to break the N-H bond and dissociate the H atom from these ternary amides. Of particular interest, there was a significant improvement in thermodynamics of the Li-Ti-N-H system, which had a reaction enthalpy of -46.6 kJ/mol compared with that of -75.67 kJ/mol in the Li—N—H system. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22974415 Exemplaires
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Titre : Galvanic leaching of chalcopyrite in atmospheric pressure and sulfate media : kinetic and surface studies Type de document : texte imprimé Auteurs : S. M. Javad Koleini, Auteur ; M. Jafarian, Auteur ; M. Abdollahy, Auteur Année de publication : 2010 Article en page(s) : pp. 5997–6002 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Galvanic leaching Kinetic Résumé : Chalcopyrite leaching rate in atmospheric pressure and in sulfate media with ferric ion is low because of passive layer formation around chalcopyrite particles. In this investigation pyrite is used as a catalyst of chalcopyrite leaching. Because of galvanic interaction between chalcopyrite and pyrite, the chalcopyrite leaching rate is increased. Effects of parameters such as stirring speed, pyrite to chalcopyrite ratio, solution potential, temperature, and initial acid concentration were investigated. Results showed that maximum copper recovery (more than 95%) is obtained in less than 24 h, stirring speed of 1150 rpm, pyrite to chalcopyrite ratio 4, solution potential 410 mV, temperature 85 °C, and initial sulfuric acid concentration 45 g/L. Also, kinetic investigation showed that chalcopyrite dissolution in the presence of pyrite followed the shrinking core model and the reaction was controlled by the surface reaction. Activation energy (Ea) was calculated at 77.79 kJ/mol. Surface studies showed that in the absence of pyrite, the surface of chalcopyrite particles was covered by passive layer. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100017u
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 5997–6002[article] Galvanic leaching of chalcopyrite in atmospheric pressure and sulfate media : kinetic and surface studies [texte imprimé] / S. M. Javad Koleini, Auteur ; M. Jafarian, Auteur ; M. Abdollahy, Auteur . - 2010 . - pp. 5997–6002.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 5997–6002
Mots-clés : Galvanic leaching Kinetic Résumé : Chalcopyrite leaching rate in atmospheric pressure and in sulfate media with ferric ion is low because of passive layer formation around chalcopyrite particles. In this investigation pyrite is used as a catalyst of chalcopyrite leaching. Because of galvanic interaction between chalcopyrite and pyrite, the chalcopyrite leaching rate is increased. Effects of parameters such as stirring speed, pyrite to chalcopyrite ratio, solution potential, temperature, and initial acid concentration were investigated. Results showed that maximum copper recovery (more than 95%) is obtained in less than 24 h, stirring speed of 1150 rpm, pyrite to chalcopyrite ratio 4, solution potential 410 mV, temperature 85 °C, and initial sulfuric acid concentration 45 g/L. Also, kinetic investigation showed that chalcopyrite dissolution in the presence of pyrite followed the shrinking core model and the reaction was controlled by the surface reaction. Activation energy (Ea) was calculated at 77.79 kJ/mol. Surface studies showed that in the absence of pyrite, the surface of chalcopyrite particles was covered by passive layer. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100017u Exemplaires
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Titre : The thermal property and flame retardant mechanism of intumescent flame retardant paraffin system with metal Type de document : texte imprimé Auteurs : Ping Zhang, Auteur ; Lei Song, Auteur ; Hongdian Lu, Auteur Année de publication : 2010 Article en page(s) : pp. 6003–6009 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Thermal properties Résumé : The influences of metal (iron, magnesium, aluminum, and zinc) on thermal properties for paraffin/intumescent flame retardants (IFR) as a phase change material were studied in this paper. Thermogravimetric analysis (TGA), thermogravimetric analysis−Fourier transform infrared spectrometry (TGA-FTIR), microscale combustion calorimetry (MCC), cone calorimetry (CONE), and differential scanning calorimetry (DSC) were used to characterize the thermal properties of the sample. The results revealed that metal could affect the thermal degradation and increase the char yield for a paraffin/IFR system. The volatilized products for the combustible gases were decreased, and carbon dioxide was increased for paraffin/IFR with metal compared to that without metal. Also, the flame retardant efficiency of IFR in paraffin could be improved by adding metal. However, the changes of the thermal properties for the metal−PCM were not in accord with increasing metal in the paraffin/IFR system. Also, the flame retardant mechanism for paraffin/IFR with metal was proposed. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1001422
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6003–6009[article] The thermal property and flame retardant mechanism of intumescent flame retardant paraffin system with metal [texte imprimé] / Ping Zhang, Auteur ; Lei Song, Auteur ; Hongdian Lu, Auteur . - 2010 . - pp. 6003–6009.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6003–6009
Mots-clés : Thermal properties Résumé : The influences of metal (iron, magnesium, aluminum, and zinc) on thermal properties for paraffin/intumescent flame retardants (IFR) as a phase change material were studied in this paper. Thermogravimetric analysis (TGA), thermogravimetric analysis−Fourier transform infrared spectrometry (TGA-FTIR), microscale combustion calorimetry (MCC), cone calorimetry (CONE), and differential scanning calorimetry (DSC) were used to characterize the thermal properties of the sample. The results revealed that metal could affect the thermal degradation and increase the char yield for a paraffin/IFR system. The volatilized products for the combustible gases were decreased, and carbon dioxide was increased for paraffin/IFR with metal compared to that without metal. Also, the flame retardant efficiency of IFR in paraffin could be improved by adding metal. However, the changes of the thermal properties for the metal−PCM were not in accord with increasing metal in the paraffin/IFR system. Also, the flame retardant mechanism for paraffin/IFR with metal was proposed. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1001422 Exemplaires
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Titre : Synthesis of vinylidene fluoride via reaction of chlorodifluoromethane (HCFC - 22) with methane Type de document : texte imprimé Auteurs : Wenfeng Han, Auteur ; Eric M. Kennedy, Auteur ; John C. Mackie, Auteur Année de publication : 2010 Article en page(s) : pp. 6010–6019 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Methane Gas phase reaction Résumé : The gas-phase reaction of CH4 and CHClF2 (HCFC-22, R22) has been studied in an alumina tubular reactor at atmospheric pressure and in the temperature range of 673−1073 K. The motivation of the investigation is to assess this process as a potential route for the treatment of CHClF2, as well as a technology for the synthesis of CH2═CF2 (vinylidene fluoride, VDF). Under the conditions studied, the major products are C2F4, CH2═CF2, HF, and HCl. Minor products detected include C2HF3, C2H2, CHF3, C2H3F, C2H2F4, CH2F2, C3F6, CH3Cl. A mechanistic interpretation of the results is proposed, including the reactions involved in the initial decomposition of CHClF2, those contributing to the activation of CH4 and developing the pathways leading to the formation of product species. The result of changing feed ratio experiments is consistent with the reaction mechanism developed. The introduction of small amounts of O2 improves the conversion of CH4 and formation of CH2═CF2 markedly. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100338j
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6010–6019[article] Synthesis of vinylidene fluoride via reaction of chlorodifluoromethane (HCFC - 22) with methane [texte imprimé] / Wenfeng Han, Auteur ; Eric M. Kennedy, Auteur ; John C. Mackie, Auteur . - 2010 . - pp. 6010–6019.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6010–6019
Mots-clés : Methane Gas phase reaction Résumé : The gas-phase reaction of CH4 and CHClF2 (HCFC-22, R22) has been studied in an alumina tubular reactor at atmospheric pressure and in the temperature range of 673−1073 K. The motivation of the investigation is to assess this process as a potential route for the treatment of CHClF2, as well as a technology for the synthesis of CH2═CF2 (vinylidene fluoride, VDF). Under the conditions studied, the major products are C2F4, CH2═CF2, HF, and HCl. Minor products detected include C2HF3, C2H2, CHF3, C2H3F, C2H2F4, CH2F2, C3F6, CH3Cl. A mechanistic interpretation of the results is proposed, including the reactions involved in the initial decomposition of CHClF2, those contributing to the activation of CH4 and developing the pathways leading to the formation of product species. The result of changing feed ratio experiments is consistent with the reaction mechanism developed. The introduction of small amounts of O2 improves the conversion of CH4 and formation of CH2═CF2 markedly. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100338j Exemplaires
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Titre : Phenol hydroxylation over Cu - containing LDHs and their calcined forms : profound cobivalent metal influence Type de document : texte imprimé Auteurs : Churchil A. Antonyraj, Auteur ; Mohini Gandhi, Auteur ; S. Kannan, Auteur Année de publication : 2010 Article en page(s) : pp. 6020–6026 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Hydroxylation phenol Résumé : Copper containing layered double hydroxides (LDHs) with less than 1 atom % Cu along with different cobivalent ions such as magnesium, zinc, nickel or cobalt at (Cu+M(II))/Al atomic ratio 3.0 were synthesized. Calcination of these materials offered mixed metal oxides (refereed here as CLDHs) without any discrete copper oxide phase as confirmed by PXRD and STEM analysis. Hydroxylation of phenol to catechol (CAT) and hydroquinone (HQ) was carried out over both as-synthesized and calcined materials. Among the cobivalent ions, zinc containing samples both in the as-synthesized and calcined forms showed very high activity while cobalt showed the minimum. Variation of copper content for CuZnAl ternary system (0.009 atom % to 0.056 atom %) showed a maximum activity for the sample with 0.038 atom % (CuZnAl-5-CLDH). High activity was attributed to better dispersion of isolated copper species as inferred through TPR measurements. Highly active CuZnAl-5-CLDH can be reused up to three cycles without any significant change in the activity. No significant variation in the conversion was noted when the reaction was scaled up to 200 times over CuZnAl-5-CLDH renders the promise of exploring it to the next level. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100399j
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6020–6026[article] Phenol hydroxylation over Cu - containing LDHs and their calcined forms : profound cobivalent metal influence [texte imprimé] / Churchil A. Antonyraj, Auteur ; Mohini Gandhi, Auteur ; S. Kannan, Auteur . - 2010 . - pp. 6020–6026.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6020–6026
Mots-clés : Hydroxylation phenol Résumé : Copper containing layered double hydroxides (LDHs) with less than 1 atom % Cu along with different cobivalent ions such as magnesium, zinc, nickel or cobalt at (Cu+M(II))/Al atomic ratio 3.0 were synthesized. Calcination of these materials offered mixed metal oxides (refereed here as CLDHs) without any discrete copper oxide phase as confirmed by PXRD and STEM analysis. Hydroxylation of phenol to catechol (CAT) and hydroquinone (HQ) was carried out over both as-synthesized and calcined materials. Among the cobivalent ions, zinc containing samples both in the as-synthesized and calcined forms showed very high activity while cobalt showed the minimum. Variation of copper content for CuZnAl ternary system (0.009 atom % to 0.056 atom %) showed a maximum activity for the sample with 0.038 atom % (CuZnAl-5-CLDH). High activity was attributed to better dispersion of isolated copper species as inferred through TPR measurements. Highly active CuZnAl-5-CLDH can be reused up to three cycles without any significant change in the activity. No significant variation in the conversion was noted when the reaction was scaled up to 200 times over CuZnAl-5-CLDH renders the promise of exploring it to the next level. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100399j Exemplaires
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Titre : Ketonization reactions of carboxylic acids and esters over ceria − zirconia as biomass - upgrading processes Type de document : texte imprimé Auteurs : Christian A. Gaertner, Auteur ; Juan Carlos Serrano-Ruiz, Auteur ; Drew J. Braden, Auteur Année de publication : 2010 Article en page(s) : pp. 6027–6033 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Carboxylic acids Résumé : Carboxylic acids and esters are common intermediate products formed in biomass conversion processes. Reaction kinetics studies for upgrading mixtures containing carboxylic acids and esters by ketonization reactions (to achieve C−C coupling) over a ceria−zirconia catalyst have been carried out using butanoic acid, pentanoic acid, and hexanoic acid at temperatures of 548, 573, 598, and 623 K. The results from these experimental studies have been consolidated and described using kinetic models. For the ketonization of hexanoic acid, a kinetic model, previously developed for hexanoic acid, has been modified and extended to describe a wider and more applicable concentration range, between 2.5 and 75 mol %. Furthermore, the homo- and the cross-ketonization of butanoic acid, pentanoic acid, and hexanoic acid have been studied, showing that the rate of cross-ketonization is faster than the rate of homo-ketonization. Because esters are common side products of biomass conversion processes, formed by the esterification of acids with primary and second alcohols, the reaction kinetics for the direct ketonization of esters has also been studied, showing that ester ketonization is slower than ketonization of the corresponding acid. Finally, a kinetic model has been developed to describe the experimentally observed product distribution obtained by reacting a mixture of different biomass-derived species over a ceria−zirconia catalyst. The model includes the ketonization of acids and the ketonization of esters as well as the esterification of acids with primary and secondary alcohols. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1004338
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6027–6033[article] Ketonization reactions of carboxylic acids and esters over ceria − zirconia as biomass - upgrading processes [texte imprimé] / Christian A. Gaertner, Auteur ; Juan Carlos Serrano-Ruiz, Auteur ; Drew J. Braden, Auteur . - 2010 . - pp. 6027–6033.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6027–6033
Mots-clés : Carboxylic acids Résumé : Carboxylic acids and esters are common intermediate products formed in biomass conversion processes. Reaction kinetics studies for upgrading mixtures containing carboxylic acids and esters by ketonization reactions (to achieve C−C coupling) over a ceria−zirconia catalyst have been carried out using butanoic acid, pentanoic acid, and hexanoic acid at temperatures of 548, 573, 598, and 623 K. The results from these experimental studies have been consolidated and described using kinetic models. For the ketonization of hexanoic acid, a kinetic model, previously developed for hexanoic acid, has been modified and extended to describe a wider and more applicable concentration range, between 2.5 and 75 mol %. Furthermore, the homo- and the cross-ketonization of butanoic acid, pentanoic acid, and hexanoic acid have been studied, showing that the rate of cross-ketonization is faster than the rate of homo-ketonization. Because esters are common side products of biomass conversion processes, formed by the esterification of acids with primary and second alcohols, the reaction kinetics for the direct ketonization of esters has also been studied, showing that ester ketonization is slower than ketonization of the corresponding acid. Finally, a kinetic model has been developed to describe the experimentally observed product distribution obtained by reacting a mixture of different biomass-derived species over a ceria−zirconia catalyst. The model includes the ketonization of acids and the ketonization of esters as well as the esterification of acids with primary and secondary alcohols. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1004338 Exemplaires
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Titre : Preparation and ammonium adsorption properties of biotite - based hydrogel composites Type de document : texte imprimé Auteurs : Yian Zheng, Auteur ; Aiqin Wang, Auteur Année de publication : 2010 Article en page(s) : pp. 6034-6041 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Composite material Adsorption Preparation Résumé : We present here a simple and effective strategy to obtain a series of hydrogel composites using biotite (BT particles and poly(acrylic acid) (PAA) as the inorganic and organic components, respectively. These hydroge composites were prepared at room temperature via a self-induced redox system based on ammonium persulfate and Fe(II) arisen from iron-rich BT. After NaOH activation, as-prepared hydrogel composites were used as the adsorbents to remove ammonium (NH4+) from its aqueous solution. The effects of preparation and adsorption conditions on NH4+ removal were investigated. The results show that the adsorption of NH4+ onto as-prepared PAA/BT (30%) is complete within 15 min, with the equilibrium adsorption capacity of 32.87 mg N/g at an initial NH4+ concentration of 100 mg N/L. In addition, the reusability of as-preparec PAA/BT for NH4+ removal was evaluated and the adsorption mechanism of NH4+ onto as-prepared hydroge composite was proposed. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22974421
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6034-6041[article] Preparation and ammonium adsorption properties of biotite - based hydrogel composites [texte imprimé] / Yian Zheng, Auteur ; Aiqin Wang, Auteur . - 2010 . - pp. 6034-6041.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6034-6041
Mots-clés : Composite material Adsorption Preparation Résumé : We present here a simple and effective strategy to obtain a series of hydrogel composites using biotite (BT particles and poly(acrylic acid) (PAA) as the inorganic and organic components, respectively. These hydroge composites were prepared at room temperature via a self-induced redox system based on ammonium persulfate and Fe(II) arisen from iron-rich BT. After NaOH activation, as-prepared hydrogel composites were used as the adsorbents to remove ammonium (NH4+) from its aqueous solution. The effects of preparation and adsorption conditions on NH4+ removal were investigated. The results show that the adsorption of NH4+ onto as-prepared PAA/BT (30%) is complete within 15 min, with the equilibrium adsorption capacity of 32.87 mg N/g at an initial NH4+ concentration of 100 mg N/L. In addition, the reusability of as-preparec PAA/BT for NH4+ removal was evaluated and the adsorption mechanism of NH4+ onto as-prepared hydroge composite was proposed. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22974421 Exemplaires
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Titre : Influence of semibatch emulsification process conditions on the physical characteristics of highly concentrated water - in - oil emulsions Type de document : texte imprimé Auteurs : Oscar A. Alvarez, Auteur ; Lionel Choplin, Auteur ; Veronique Sadtler, Auteur Année de publication : 2010 Article en page(s) : pp. 6042–6046 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Oil Emulsions Résumé : We studied the energy consumption per unit volume during preparation of highly concentrated water-in-oil emulsions in a two-step semibatch process. In particular, we studied the effect of two process variables, the water addition flow rate (Qw) and the agitation speed (N). The oil used for emulsion preparation was n-dodecane, the surfactant was sorbitan monooleate (Span 80) and deionized water was used for the dispersed phase. The results obtained showed that two steps were required to get complete incorporation of the dispersed phase and a homogeneous and stable gel-emulsion. With the help of independent physical characteristics measurement performed at the end of the preparation process, we established two functional relationships, relating storage modulus (G′) with energy consumption (Ev), (G′ Ev0.6), and average liquid cell size (Rm) of the dispersed phase with energy consumption (Ev), (Rm EV−0.3). A structural scaling law can be deduced that relates the elastic modulus to the reciprocal of the square of the average liquid’s cell size of the gel-emulsion, corroborated by independent measurements and predicted by recent published models. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9020073
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6042–6046[article] Influence of semibatch emulsification process conditions on the physical characteristics of highly concentrated water - in - oil emulsions [texte imprimé] / Oscar A. Alvarez, Auteur ; Lionel Choplin, Auteur ; Veronique Sadtler, Auteur . - 2010 . - pp. 6042–6046.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6042–6046
Mots-clés : Oil Emulsions Résumé : We studied the energy consumption per unit volume during preparation of highly concentrated water-in-oil emulsions in a two-step semibatch process. In particular, we studied the effect of two process variables, the water addition flow rate (Qw) and the agitation speed (N). The oil used for emulsion preparation was n-dodecane, the surfactant was sorbitan monooleate (Span 80) and deionized water was used for the dispersed phase. The results obtained showed that two steps were required to get complete incorporation of the dispersed phase and a homogeneous and stable gel-emulsion. With the help of independent physical characteristics measurement performed at the end of the preparation process, we established two functional relationships, relating storage modulus (G′) with energy consumption (Ev), (G′ Ev0.6), and average liquid cell size (Rm) of the dispersed phase with energy consumption (Ev), (Rm EV−0.3). A structural scaling law can be deduced that relates the elastic modulus to the reciprocal of the square of the average liquid’s cell size of the gel-emulsion, corroborated by independent measurements and predicted by recent published models. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9020073 Exemplaires
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Titre : Rapid synthesis of uniform magnetic microspheres by combing premix membrane emulsification and in situ formation techniques Type de document : texte imprimé Auteurs : Jian Yang, Auteur ; Dong-Xia Hao, Auteur ; Cai-Xia Bi, Auteur Année de publication : 2010 Article en page(s) : pp. 6047–6053 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Magnetic Microspheres Résumé : Uniform magnetic poly(styrene-co-2-hydroxyethyl methacrylate) (PST-HEMA) microspheres were fabricated by a novel route combining premix membrane emulsification of double emulsion and an in situ magnetization technique. The fabrication involved, first, the preparation of uniform double W/O/W emulsions with ferrous ferric solution as the internal water phase and dichloromethane dissolved with PST-HEMA as the oil phase by premix SPG membrane emulsification. Then, the inner ferrous ferric solution was in situ magnetized into nanoparticles by adding the ammonia solution into the external water phase. This W/O/S emulsion was finally solidified into microspores by solvent evaporation. Results showed that the in situ magnetization technique could effectively overcome the encapsulation difficulties in traditional synthesis routes due to poorer affinity between iron oxide nanoparticles and polymer, and facilitated the enhancement of encapsulation efficiency with a high magnetization up to 14.23 emu/g. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902053u
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6047–6053[article] Rapid synthesis of uniform magnetic microspheres by combing premix membrane emulsification and in situ formation techniques [texte imprimé] / Jian Yang, Auteur ; Dong-Xia Hao, Auteur ; Cai-Xia Bi, Auteur . - 2010 . - pp. 6047–6053.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6047–6053
Mots-clés : Magnetic Microspheres Résumé : Uniform magnetic poly(styrene-co-2-hydroxyethyl methacrylate) (PST-HEMA) microspheres were fabricated by a novel route combining premix membrane emulsification of double emulsion and an in situ magnetization technique. The fabrication involved, first, the preparation of uniform double W/O/W emulsions with ferrous ferric solution as the internal water phase and dichloromethane dissolved with PST-HEMA as the oil phase by premix SPG membrane emulsification. Then, the inner ferrous ferric solution was in situ magnetized into nanoparticles by adding the ammonia solution into the external water phase. This W/O/S emulsion was finally solidified into microspores by solvent evaporation. Results showed that the in situ magnetization technique could effectively overcome the encapsulation difficulties in traditional synthesis routes due to poorer affinity between iron oxide nanoparticles and polymer, and facilitated the enhancement of encapsulation efficiency with a high magnetization up to 14.23 emu/g. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902053u Exemplaires
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Titre : Microbial Corrosion of aluminum 2024 aeronautical alloy by hydrocarbon degrading bacteria bacillus cereus ACE4 and serratia marcescens ACE2 Type de document : texte imprimé Auteurs : Aruliah Rajasekar, Auteur ; Yen-Peng Ting, Auteur Année de publication : 2010 Article en page(s) : pp. 6054-6061 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Bacteria Corrosion Résumé : Microbial growth and contamination in aviation fuel storage tanks and aircraft wing tanks cause metal corrosion plugging of the fuel filter, and increased maintenance costs associated with these problems. This paper report the microbiologically induced corrosion (MIC) and electrochemical behavior of aluminum alloy (AA 2024 in the presence of hydrocarbon-degrading bacteria Bacillus cereus ACE4 (a Gram-positive bacteria) and Serrati marcescens ACE2 (a Gram-negative bacteria). Electrochemical impedance spectroscopy and metallographic analysis of the metal AA 2024 exposed to a simulated fuel tank environment showed that the bacteria caused pitting corrosion. Scanning electron microscopy-energy-dispersive X-ray spectroscopy analysis (SEM-EDAX) atomic force microscopy (AFM), and Fourier-transform infrared spectroscopy (FTIR) analyses of the aluminum alloy coupons with bacterial biofilm developed after exposure to minimal salt medium confirmed tha extracellular polymeric substances accumulate with exposure time and revealed that biofilms are formed as microcolonies, which subsequently cause pitting corrosion. Hydrophobicity of the cell surface was examined using bacterial adhesion to hydrocarbons (BATH) assay. The hydrophobicity and emulsification index of B cereus ACE4 grown in n-hexadecane containing medium was higher (86% and E72 85%) than that of S marcescens ACE2 (60% and E72 75%), This significant difference may be due to the efficiency of biosurfactan production, which contributes to increase in the cell surface hydrophobicity of the B. cereus ACE4, and enhanced bacterial adhesion on the AA 2024 metal surface. The corrosion damage caused by B. cereus ACE4 is vigorous compared with that from S. marcescens ACE2. This study provides some insight into the MIC of AA 2024 by two hydrocarbon-degrading bacteria in fuel/water mixtures. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22974424
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6054-6061[article] Microbial Corrosion of aluminum 2024 aeronautical alloy by hydrocarbon degrading bacteria bacillus cereus ACE4 and serratia marcescens ACE2 [texte imprimé] / Aruliah Rajasekar, Auteur ; Yen-Peng Ting, Auteur . - 2010 . - pp. 6054-6061.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6054-6061
Mots-clés : Bacteria Corrosion Résumé : Microbial growth and contamination in aviation fuel storage tanks and aircraft wing tanks cause metal corrosion plugging of the fuel filter, and increased maintenance costs associated with these problems. This paper report the microbiologically induced corrosion (MIC) and electrochemical behavior of aluminum alloy (AA 2024 in the presence of hydrocarbon-degrading bacteria Bacillus cereus ACE4 (a Gram-positive bacteria) and Serrati marcescens ACE2 (a Gram-negative bacteria). Electrochemical impedance spectroscopy and metallographic analysis of the metal AA 2024 exposed to a simulated fuel tank environment showed that the bacteria caused pitting corrosion. Scanning electron microscopy-energy-dispersive X-ray spectroscopy analysis (SEM-EDAX) atomic force microscopy (AFM), and Fourier-transform infrared spectroscopy (FTIR) analyses of the aluminum alloy coupons with bacterial biofilm developed after exposure to minimal salt medium confirmed tha extracellular polymeric substances accumulate with exposure time and revealed that biofilms are formed as microcolonies, which subsequently cause pitting corrosion. Hydrophobicity of the cell surface was examined using bacterial adhesion to hydrocarbons (BATH) assay. The hydrophobicity and emulsification index of B cereus ACE4 grown in n-hexadecane containing medium was higher (86% and E72 85%) than that of S marcescens ACE2 (60% and E72 75%), This significant difference may be due to the efficiency of biosurfactan production, which contributes to increase in the cell surface hydrophobicity of the B. cereus ACE4, and enhanced bacterial adhesion on the AA 2024 metal surface. The corrosion damage caused by B. cereus ACE4 is vigorous compared with that from S. marcescens ACE2. This study provides some insight into the MIC of AA 2024 by two hydrocarbon-degrading bacteria in fuel/water mixtures. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22974424 Exemplaires
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Titre : Microstructure and performance investigation of a solid oxide fuel cells based on highly asymmetric YSZ microtubular electrolytes Type de document : texte imprimé Auteurs : Krzysztof Kanawka, Auteur ; Francesco Dal Grande, Auteur ; Zhentao Wu, Auteur Année de publication : 2010 Article en page(s) : pp. 6062-6068 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Electrolyte Solid oxide fuel cell Microstructure Résumé : A combined phase inversion and sintering technique was used to fabricate highly asymmetric yttria-stabilized zirconia (YSZ) hollow fibers with a 1.9 mm external diameter and 210 μm total wall thickness. These consiste of a thin (∼10 μm), dense outer layer and a much thicker (∼200 μm) inner layer with finger-like voids. Suc highly asymmetric structures formed gas-tight electrolytes and mechanical supports of a microtubular solid oxide fuel cell (SOFC). Nickel oxide-yttria-stabilized zirconia (NiO-YSZ) particles were infused into the pores from alcoholic dispersions and then sintered at 1300 °C, prior to electroless Ni layers being deposited forming composite anodes. The Ni layer deposited by electroless plating had the function of improving the anodic current collection. Cathodes were deposited by slurry-coating lanthanum strontium manganite particles onto the outer surfaces of YSZ hollow fibers, followed by sintering at 1000 °C and reduction of the anode at 800 °C in a hydrogen environment, completing the fabrication of the microtubular SOFCs. Mechanical strengths of ∼226 MPa were derived from three-point bending tests on hollow fibers sintered at 1450 °C. Initial SOFC performance measurements with 5% H2 as the fuel and air as the oxidant resulted in maximum power densities of 18 mW cm 2 at 800 °C. This low value resulted largely from the discontinuous nature of the electrolessly deposited nickel anode; present work aims to improve its structure and hence SOFC performance. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22974425
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6062-6068[article] Microstructure and performance investigation of a solid oxide fuel cells based on highly asymmetric YSZ microtubular electrolytes [texte imprimé] / Krzysztof Kanawka, Auteur ; Francesco Dal Grande, Auteur ; Zhentao Wu, Auteur . - 2010 . - pp. 6062-6068.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6062-6068
Mots-clés : Electrolyte Solid oxide fuel cell Microstructure Résumé : A combined phase inversion and sintering technique was used to fabricate highly asymmetric yttria-stabilized zirconia (YSZ) hollow fibers with a 1.9 mm external diameter and 210 μm total wall thickness. These consiste of a thin (∼10 μm), dense outer layer and a much thicker (∼200 μm) inner layer with finger-like voids. Suc highly asymmetric structures formed gas-tight electrolytes and mechanical supports of a microtubular solid oxide fuel cell (SOFC). Nickel oxide-yttria-stabilized zirconia (NiO-YSZ) particles were infused into the pores from alcoholic dispersions and then sintered at 1300 °C, prior to electroless Ni layers being deposited forming composite anodes. The Ni layer deposited by electroless plating had the function of improving the anodic current collection. Cathodes were deposited by slurry-coating lanthanum strontium manganite particles onto the outer surfaces of YSZ hollow fibers, followed by sintering at 1000 °C and reduction of the anode at 800 °C in a hydrogen environment, completing the fabrication of the microtubular SOFCs. Mechanical strengths of ∼226 MPa were derived from three-point bending tests on hollow fibers sintered at 1450 °C. Initial SOFC performance measurements with 5% H2 as the fuel and air as the oxidant resulted in maximum power densities of 18 mW cm 2 at 800 °C. This low value resulted largely from the discontinuous nature of the electrolessly deposited nickel anode; present work aims to improve its structure and hence SOFC performance. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22974425 Exemplaires
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Titre : Novel materials from sesame husks and unsaturated polyester resin Type de document : texte imprimé Auteurs : Dipa Ray, Auteur ; Keya Das, Auteur ; S. N. Ghosh, Auteur Année de publication : 2010 Article en page(s) : pp. 6069–6074 Note générale : Industrial chemistry Langues : Anglais (eng) Résumé : Sesame husks were used as filler, for the first time, to reinforce unsaturated polyester resin matrix composites. The sesame husk particles were subjected to an alkali treatment with 5% NaOH solution and were characterized with XRD and SEM. Composites were fabricated with untreated as well as alkali-treated sesame husks (33 wt % filler loading) and were characterized for their flexural properties, impact strength, dynamic mechanical properties, fracture behavior, water absorption characteristics, and thermal degradation behavior. The flexural strength, flexural modulus, and impact strength increased by 30%, 40%, and 46%, respectively, in the alkali-treated sesame husk-reinforced composites compared to those of untreated sesame husk-reinforced composites. Here, the increase in flexural strength properties was accompanied with increased impact strength, which is a unique feature of these composites. Water absorption was found to be 3.9% after 7 days in both the untreated as well as alkali-treated sesame husk-reinforced composites.
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6069–6074[article] Novel materials from sesame husks and unsaturated polyester resin [texte imprimé] / Dipa Ray, Auteur ; Keya Das, Auteur ; S. N. Ghosh, Auteur . - 2010 . - pp. 6069–6074.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6069–6074
Résumé : Sesame husks were used as filler, for the first time, to reinforce unsaturated polyester resin matrix composites. The sesame husk particles were subjected to an alkali treatment with 5% NaOH solution and were characterized with XRD and SEM. Composites were fabricated with untreated as well as alkali-treated sesame husks (33 wt % filler loading) and were characterized for their flexural properties, impact strength, dynamic mechanical properties, fracture behavior, water absorption characteristics, and thermal degradation behavior. The flexural strength, flexural modulus, and impact strength increased by 30%, 40%, and 46%, respectively, in the alkali-treated sesame husk-reinforced composites compared to those of untreated sesame husk-reinforced composites. Here, the increase in flexural strength properties was accompanied with increased impact strength, which is a unique feature of these composites. Water absorption was found to be 3.9% after 7 days in both the untreated as well as alkali-treated sesame husk-reinforced composites. Exemplaires
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Titre : Preparation and comparison of hydrophobic cotton fabric obtained by direct fluorination and admicellar polymerization of fluoromonomers Type de document : texte imprimé Auteurs : Jayanta Maity, Auteur ; Pratik Kothary, Auteur ; Edgar A. O’Rear, Auteur Année de publication : 2010 Article en page(s) : pp. 6075–6079 Note générale : industrial chemistry Langues : Anglais (eng) Mots-clés : cotton fabrics fluorination admicellar polymerization spectroscopy Fourier transform Résumé : Two different methods of surface modification of cotton fabrics are compared: direct fluorination using elemental fluorine and admicellar polymerization, which uses a surfactant and fluoromonomer system. Sample characterization includes infrared spectroscopy, analysis of mechanical properties, analysis of wetting times, contact angle measurements, scanning electron microscopy, elemental analysis, and atomic force microscopy analysis. Fourier transform infrared spectroscopy and elemental analysis showed the presence of fluorine moieties. For direct fluorinated cotton fabric, the static contact angle was found to be 117°, and for cotton fabric modified by admicellar polymerization, the contact angle was 125°. In all cases, the presence of a very thin fluorocarbon layer on the surface was confirmed, but differences in terms of the amount of fluorochemical formed and in surface structure were also found. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100564y
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6075–6079[article] Preparation and comparison of hydrophobic cotton fabric obtained by direct fluorination and admicellar polymerization of fluoromonomers [texte imprimé] / Jayanta Maity, Auteur ; Pratik Kothary, Auteur ; Edgar A. O’Rear, Auteur . - 2010 . - pp. 6075–6079.
industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6075–6079
Mots-clés : cotton fabrics fluorination admicellar polymerization spectroscopy Fourier transform Résumé : Two different methods of surface modification of cotton fabrics are compared: direct fluorination using elemental fluorine and admicellar polymerization, which uses a surfactant and fluoromonomer system. Sample characterization includes infrared spectroscopy, analysis of mechanical properties, analysis of wetting times, contact angle measurements, scanning electron microscopy, elemental analysis, and atomic force microscopy analysis. Fourier transform infrared spectroscopy and elemental analysis showed the presence of fluorine moieties. For direct fluorinated cotton fabric, the static contact angle was found to be 117°, and for cotton fabric modified by admicellar polymerization, the contact angle was 125°. In all cases, the presence of a very thin fluorocarbon layer on the surface was confirmed, but differences in terms of the amount of fluorochemical formed and in surface structure were also found. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100564y Exemplaires
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Titre : All-at-once and step-wise detailed retrofit of heat exchanger networks using an MILP model Type de document : texte imprimé Auteurs : Duy Quang Nguyen, Auteur ; Andres Barbaro, Auteur ; Narumon Vipanurat, Auteur Année de publication : 2010 Article en page(s) : pp. 6080–6103 Note générale : industrial chemistry Langues : Anglais (eng) Mots-clés : MILP model Résumé : This paper builds upon the MILP model developed by Barbaro and Bagajewicz (New Rigorous One-Step MILP Formulation for Heat Exchanger Network Synthesis. Comp. Chem. Eng. 2005, 1945−1976), which allows the rigorous one-step grassroots design of heat exchanger networks. For the retrofit, we consider the cases of addition and relocation of heat exchangers allowing control of repiping costs as well as splitting. While previous works considered area reduction in existing exchangers, they very rarely took into account the associated cost, which we now do. We also add all the costs associated with new shells, area addition to existing shells, relocation, and piping changes. We illustrate the power of the formulation with a small example as well as with a crude fractionation unit. Moreover, we discuss step-by-step changes that allow better planning around turnarounds as opposed to an all-at-once solution. Finally, the model also offers a good level of flexibility that opens room for decision making by the users such as allowing/disallowing splitting, considering area and shell additions only (i.e., disallowing relocation), limiting the number of new exchangers and/or the number of relocations, etc. Various design case studies of a same process example are considered to demonstrate the flexibility and versatility of the model. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901235c
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6080–6103[article] All-at-once and step-wise detailed retrofit of heat exchanger networks using an MILP model [texte imprimé] / Duy Quang Nguyen, Auteur ; Andres Barbaro, Auteur ; Narumon Vipanurat, Auteur . - 2010 . - pp. 6080–6103.
industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6080–6103
Mots-clés : MILP model Résumé : This paper builds upon the MILP model developed by Barbaro and Bagajewicz (New Rigorous One-Step MILP Formulation for Heat Exchanger Network Synthesis. Comp. Chem. Eng. 2005, 1945−1976), which allows the rigorous one-step grassroots design of heat exchanger networks. For the retrofit, we consider the cases of addition and relocation of heat exchangers allowing control of repiping costs as well as splitting. While previous works considered area reduction in existing exchangers, they very rarely took into account the associated cost, which we now do. We also add all the costs associated with new shells, area addition to existing shells, relocation, and piping changes. We illustrate the power of the formulation with a small example as well as with a crude fractionation unit. Moreover, we discuss step-by-step changes that allow better planning around turnarounds as opposed to an all-at-once solution. Finally, the model also offers a good level of flexibility that opens room for decision making by the users such as allowing/disallowing splitting, considering area and shell additions only (i.e., disallowing relocation), limiting the number of new exchangers and/or the number of relocations, etc. Various design case studies of a same process example are considered to demonstrate the flexibility and versatility of the model. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901235c Exemplaires
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Titre : Operation planning of multiparcel tankers under fuel price uncertainty Type de document : texte imprimé Auteurs : H. C. Oh, Auteur ; A. Karimi, Auteur Année de publication : 2010 Article en page(s) : pp. 6104–6114 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Maritime logistics multiparcel tanker mixed-integer linear programming model Résumé : Maritime logistics is the workhorse of the growing global chemical trade. Fuel expenses claim up to 90% of the daily operating cost of a multiparcel tanker, and a tanker’s fuel consumption varies with the cube of its speed. This combined with high fuel prices makes it crucial that the tanker owners manage tanker speed and fuel purchases in a prudent manner. The volatility in fuel prices and their significant variations across refueling ports make this a difficult task, and systematic optimization can aid the decision-making process. Surprisingly, no literature model addresses this issue for multiparcel tankers. We propose a novel mixed-integer linear programming model that optimizes the operation of a multiparcel tanker in the presence of uncertain fuel prices. Given the route and cargo details of a tanker, it determines the optimal voyage speeds and a refueling plan that minimizes the expected total operating cost. We use a case study derived from industrial data to illustrate the application of our new model. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901551j
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6104–6114[article] Operation planning of multiparcel tankers under fuel price uncertainty [texte imprimé] / H. C. Oh, Auteur ; A. Karimi, Auteur . - 2010 . - pp. 6104–6114.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6104–6114
Mots-clés : Maritime logistics multiparcel tanker mixed-integer linear programming model Résumé : Maritime logistics is the workhorse of the growing global chemical trade. Fuel expenses claim up to 90% of the daily operating cost of a multiparcel tanker, and a tanker’s fuel consumption varies with the cube of its speed. This combined with high fuel prices makes it crucial that the tanker owners manage tanker speed and fuel purchases in a prudent manner. The volatility in fuel prices and their significant variations across refueling ports make this a difficult task, and systematic optimization can aid the decision-making process. Surprisingly, no literature model addresses this issue for multiparcel tankers. We propose a novel mixed-integer linear programming model that optimizes the operation of a multiparcel tanker in the presence of uncertain fuel prices. Given the route and cargo details of a tanker, it determines the optimal voyage speeds and a refueling plan that minimizes the expected total operating cost. We use a case study derived from industrial data to illustrate the application of our new model. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901551j Exemplaires
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Titre : A new pairing method for multivariable processes Type de document : texte imprimé Auteurs : Yongfang Cheng, Auteur ; Shaoyuan Li, Auteur Année de publication : 2010 Article en page(s) : pp. 6115–6124 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : multivariable processes pairing methods loops Résumé : As far as the pairing of multivariable processes is concerned, with the existing method based on the relative gain array (RGA) and Niederlinski index (NI), the interactions among loops are analyzed by the open-loop gains change when all the other loops change from open states to closed states. In this method, the internal interactions among the other loops are hidden, that is, several groups of other loops with different internal interactions can result in the same effect toward the loop considered. Therefore, according to the existing method, there may be more than one feasible way of pairing. To analyze the interactions under these feasible pairings further and get one pairing way with relatively weak interactions, in this paper, a new method of pairing is proposed based on the analysis of interactions between any two loops. By means of relative gain table and relative gain graph, the interactions between two random loops of a n × n system can be analyzed vividly when the number of closed loops within the (n − 1)-dimensional subsystem decreases gradually. On the definition of a new criterion to weigh the mutual interaction between loops, a new pairing method is brought forward. Finally, three examples are used to validate the effectiveness of the proposed method. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901787u
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6115–6124[article] A new pairing method for multivariable processes [texte imprimé] / Yongfang Cheng, Auteur ; Shaoyuan Li, Auteur . - 2010 . - pp. 6115–6124.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6115–6124
Mots-clés : multivariable processes pairing methods loops Résumé : As far as the pairing of multivariable processes is concerned, with the existing method based on the relative gain array (RGA) and Niederlinski index (NI), the interactions among loops are analyzed by the open-loop gains change when all the other loops change from open states to closed states. In this method, the internal interactions among the other loops are hidden, that is, several groups of other loops with different internal interactions can result in the same effect toward the loop considered. Therefore, according to the existing method, there may be more than one feasible way of pairing. To analyze the interactions under these feasible pairings further and get one pairing way with relatively weak interactions, in this paper, a new method of pairing is proposed based on the analysis of interactions between any two loops. By means of relative gain table and relative gain graph, the interactions between two random loops of a n × n system can be analyzed vividly when the number of closed loops within the (n − 1)-dimensional subsystem decreases gradually. On the definition of a new criterion to weigh the mutual interaction between loops, a new pairing method is brought forward. Finally, three examples are used to validate the effectiveness of the proposed method. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901787u Exemplaires
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Titre : A computationally efficient algorithm for testing the identifiability of polynomial systems with applications to biological systems Type de document : texte imprimé Auteurs : Amos Ben-Zvi, Auteur Année de publication : 2010 Article en page(s) : pp. 6125–6134 Note générale : Indusstrial chemistry Langues : Anglais (eng) Résumé : Mathematical models of physical systems often contain many more parameters than can be estimated from observations. It is useful to check whether such models are structurally identifiable before choosing an experimental plan for parameter estimation. Many identifiability tests have been proposed in the literature. However, the proposed methods are computationally complex, or even intractable, for systems containing more than a handful of states or parameters. In this work, a linear algebra-based approach for testing ordinary differential equations and index-one differential algebraic equation systems with linear output maps for local structural identifiability is presented. The proposed method is computationally efficient, as it does not require repeated differentiation of the model equations. Furthermore, the proposed model can be used by experimenters to determine which set of measurements should be made in order to estimate specific parameters within the model. The effectiveness of the proposed approach is demonstrated by testing the identifiability of a 15-state model describing NF−κB regulation. The model is shown to be identifiable even if process measurements are related to the state variables by proportionality constants (themselves unknown). Furthermore, the proposed procedure is used to compute a table that relates to each unknown parameter or parameter set a set of state variables whose observation is sufficient for parameter estimation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9018512
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6125–6134[article] A computationally efficient algorithm for testing the identifiability of polynomial systems with applications to biological systems [texte imprimé] / Amos Ben-Zvi, Auteur . - 2010 . - pp. 6125–6134.
Indusstrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6125–6134
Résumé : Mathematical models of physical systems often contain many more parameters than can be estimated from observations. It is useful to check whether such models are structurally identifiable before choosing an experimental plan for parameter estimation. Many identifiability tests have been proposed in the literature. However, the proposed methods are computationally complex, or even intractable, for systems containing more than a handful of states or parameters. In this work, a linear algebra-based approach for testing ordinary differential equations and index-one differential algebraic equation systems with linear output maps for local structural identifiability is presented. The proposed method is computationally efficient, as it does not require repeated differentiation of the model equations. Furthermore, the proposed model can be used by experimenters to determine which set of measurements should be made in order to estimate specific parameters within the model. The effectiveness of the proposed approach is demonstrated by testing the identifiability of a 15-state model describing NF−κB regulation. The model is shown to be identifiable even if process measurements are related to the state variables by proportionality constants (themselves unknown). Furthermore, the proposed procedure is used to compute a table that relates to each unknown parameter or parameter set a set of state variables whose observation is sufficient for parameter estimation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9018512 Exemplaires
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Titre : Comparison of dynamic and static performances of a quaternary distillation sequence Type de document : texte imprimé Auteurs : Gholamreza Baghmisheh, Auteur ; Mohammad Shahrokhi, Auteur ; Ramin Bozorgmehri, Auteur Année de publication : 2010 Article en page(s) : pp. 6135–6143 Note générale : Chemistry engineering Langues : Anglais (eng) Mots-clés : Quaternary distillation column sequences dynamic performance Résumé : In this work, steady state and dynamic performances of quaternary distillation column sequences designed based on steady state and dynamic cost functions have been investigated. To quantify the dynamic performance, product losses due to disturbances have been considered in the objective function. In addition, variations of operating costs such as utilities have been considered in the objective function. To separate a quaternary mixture into four products, 22 configurations have been used. It has been observed that the feed composition, disturbance frequency and magnitude affect the dynamic behavior strongly. To decrease the optimization computational load, a scheme that provides a suboptimal result has been proposed. By performing simultaneous optimization that requires much more computational time, it has been shown that the highest ranking configurations obtained by the proposed method are the same as those provided by simultaneous technique. The simulation results indicate that there is no clear pattern for configuration ranking based on column sequence specifications. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100169p
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6135–6143[article] Comparison of dynamic and static performances of a quaternary distillation sequence [texte imprimé] / Gholamreza Baghmisheh, Auteur ; Mohammad Shahrokhi, Auteur ; Ramin Bozorgmehri, Auteur . - 2010 . - pp. 6135–6143.
Chemistry engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6135–6143
Mots-clés : Quaternary distillation column sequences dynamic performance Résumé : In this work, steady state and dynamic performances of quaternary distillation column sequences designed based on steady state and dynamic cost functions have been investigated. To quantify the dynamic performance, product losses due to disturbances have been considered in the objective function. In addition, variations of operating costs such as utilities have been considered in the objective function. To separate a quaternary mixture into four products, 22 configurations have been used. It has been observed that the feed composition, disturbance frequency and magnitude affect the dynamic behavior strongly. To decrease the optimization computational load, a scheme that provides a suboptimal result has been proposed. By performing simultaneous optimization that requires much more computational time, it has been shown that the highest ranking configurations obtained by the proposed method are the same as those provided by simultaneous technique. The simulation results indicate that there is no clear pattern for configuration ranking based on column sequence specifications. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100169p Exemplaires
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Titre : An improved particle swarm algorithm for optimal design of plate-fin heat exchangers Type de document : texte imprimé Auteurs : Peng, Hao, Auteur ; Xiang Ling, Auteur ; En Wu, Auteur Année de publication : 2010 Article en page(s) : pp. 6144–6149 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Particle swarm optimization Plate-fin heat exchangers Résumé : In this paper, an improved particle swarm optimization (PSO) was used to optimize the structure dimensions of the plate-fin heat exchangers (PFHEs). The major objectives are to minimize the total weight and total annual cost of the PFHEs for given constrained conditions. The total weight target ensures an exchanger of the smallest size with minimum capital cost, whereas the annual cost target yields the optimum pressure drops accounting for the trade-off between power consumption and heat exchanger weight. The total length and width of the PFHE core, number of hot side layers, fin height, and pitch on each side of the PFHE are considered as optimization variables. The logarithmic mean temperature difference method is used for the design of the PFHE. Also compared with the results obtained by PSO and the traditional genetic algorithm, the PSO algorithm presents a shorter computational time and better results under the same design parameters and the same optimization variables. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1002685
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6144–6149[article] An improved particle swarm algorithm for optimal design of plate-fin heat exchangers [texte imprimé] / Peng, Hao, Auteur ; Xiang Ling, Auteur ; En Wu, Auteur . - 2010 . - pp. 6144–6149.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6144–6149
Mots-clés : Particle swarm optimization Plate-fin heat exchangers Résumé : In this paper, an improved particle swarm optimization (PSO) was used to optimize the structure dimensions of the plate-fin heat exchangers (PFHEs). The major objectives are to minimize the total weight and total annual cost of the PFHEs for given constrained conditions. The total weight target ensures an exchanger of the smallest size with minimum capital cost, whereas the annual cost target yields the optimum pressure drops accounting for the trade-off between power consumption and heat exchanger weight. The total length and width of the PFHE core, number of hot side layers, fin height, and pitch on each side of the PFHE are considered as optimization variables. The logarithmic mean temperature difference method is used for the design of the PFHE. Also compared with the results obtained by PSO and the traditional genetic algorithm, the PSO algorithm presents a shorter computational time and better results under the same design parameters and the same optimization variables. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1002685 Exemplaires
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Titre : Design and control of a methanol reactor/column process Type de document : texte imprimé Auteurs : William L. Luyben, Auteur Année de publication : 2010 Article en page(s) : pp. 6150–6163 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Methanol reactor Gas recycle streams Résumé : Methanol is one of the prime candidates for providing an alternative to petroleum-based liquid transportation fuels. It can be made from any renewable biomass hydrocarbon source by partial oxidation in an oxygen-blown gasifier to produce synthesis gas, which is then converted into methanol. The purpose of this paper is to develop the economically optimum design of a methanol reactor/distillation column system with three gas recycle streams to produce high-purity methanol from synthesis gas. The economics consider capital costs, energy costs, the value of the methanol product, and the heating value of a vent stream that is necessary for purging off inert components entering in the feed. A plantwide control structure is developed that is capable of effectively handling large disturbances in the production rate and synthesis gas composition. The unique features of this control scheme are a lack of control of pressure in the reactor/recycle gas loop and a high-pressure override controller to handle stoichiometric imbalances in the composition of the synthesis gas feed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100323d
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6150–6163[article] Design and control of a methanol reactor/column process [texte imprimé] / William L. Luyben, Auteur . - 2010 . - pp. 6150–6163.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6150–6163
Mots-clés : Methanol reactor Gas recycle streams Résumé : Methanol is one of the prime candidates for providing an alternative to petroleum-based liquid transportation fuels. It can be made from any renewable biomass hydrocarbon source by partial oxidation in an oxygen-blown gasifier to produce synthesis gas, which is then converted into methanol. The purpose of this paper is to develop the economically optimum design of a methanol reactor/distillation column system with three gas recycle streams to produce high-purity methanol from synthesis gas. The economics consider capital costs, energy costs, the value of the methanol product, and the heating value of a vent stream that is necessary for purging off inert components entering in the feed. A plantwide control structure is developed that is capable of effectively handling large disturbances in the production rate and synthesis gas composition. The unique features of this control scheme are a lack of control of pressure in the reactor/recycle gas loop and a high-pressure override controller to handle stoichiometric imbalances in the composition of the synthesis gas feed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100323d Exemplaires
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Titre : Design and control of the methoxy-methyl-heptane process Type de document : texte imprimé Auteurs : William L. Luyben, Auteur Année de publication : 2010 Article en page(s) : pp. 6164–6175 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Chemical 2-methoxy-2-methylheptane Methyl tert-butyl ether Résumé : The chemical 2-methoxy-2-methylheptane (MMH) has been proposed as a gasoline additive to replace methyl tert-butyl ether (MTBE) in order to avoid groundwater contamination. The chemistry involves the liquid-phase reversible reaction of methanol with 2-methyl-1-heptene (MH) to form MMH. However, methanol and MH also undergo an undesirable reaction to form dimethyl ether (DME) and 2-methyl-2-heptanol (MHOH). The activation energies of the two competing reactions favor high reactor temperature, which is limited by catalyst activity to 400 K. Yield of the desired product is increased by either increasing reactor size or keeping the concentration of methanol in the reactor low by using a large excess of MH in the reactor. The latter strategy results in a large recycle flow rate of MH, which increases separation costs. Thus, this process demonstrates the classic design trade-off between reactor costs and separation costs. The purpose of this paper is to explore the economics and the dynamics of this process. The cost of the MH raw material and the values of the products are somewhat uncertain. Therefore the approach adopted in this paper is to design the process for a specified yield of MMH. For a given yield, there are optimum values of reactor size and recycle flow rate that minimize total annual cost. The flowsheet features a continuous stirred tank reactor, three distillation columns, and one recycle stream. A plantwide control structure is also developed that is capable of effectively handling large disturbances in production rate and operating parameters. The limiting reactant methanol is flow-controlled to set the production rate. The fresh feed of the other reactant MH is fed to maintain a fixed total flow rate of MH (fresh feed plus recycle). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100804a
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6164–6175[article] Design and control of the methoxy-methyl-heptane process [texte imprimé] / William L. Luyben, Auteur . - 2010 . - pp. 6164–6175.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6164–6175
Mots-clés : Chemical 2-methoxy-2-methylheptane Methyl tert-butyl ether Résumé : The chemical 2-methoxy-2-methylheptane (MMH) has been proposed as a gasoline additive to replace methyl tert-butyl ether (MTBE) in order to avoid groundwater contamination. The chemistry involves the liquid-phase reversible reaction of methanol with 2-methyl-1-heptene (MH) to form MMH. However, methanol and MH also undergo an undesirable reaction to form dimethyl ether (DME) and 2-methyl-2-heptanol (MHOH). The activation energies of the two competing reactions favor high reactor temperature, which is limited by catalyst activity to 400 K. Yield of the desired product is increased by either increasing reactor size or keeping the concentration of methanol in the reactor low by using a large excess of MH in the reactor. The latter strategy results in a large recycle flow rate of MH, which increases separation costs. Thus, this process demonstrates the classic design trade-off between reactor costs and separation costs. The purpose of this paper is to explore the economics and the dynamics of this process. The cost of the MH raw material and the values of the products are somewhat uncertain. Therefore the approach adopted in this paper is to design the process for a specified yield of MMH. For a given yield, there are optimum values of reactor size and recycle flow rate that minimize total annual cost. The flowsheet features a continuous stirred tank reactor, three distillation columns, and one recycle stream. A plantwide control structure is also developed that is capable of effectively handling large disturbances in production rate and operating parameters. The limiting reactant methanol is flow-controlled to set the production rate. The fresh feed of the other reactant MH is fed to maintain a fixed total flow rate of MH (fresh feed plus recycle). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100804a Exemplaires
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Titre : Vapor-liquid equilibrium in extractive distillation of the acetone/methanol system using water as entrainer and pressure reduction Type de document : texte imprimé Auteurs : Diana C. Botía, Auteur ; Diana C. Riveros, Auteur ; Pablo Ortiz, Auteur Année de publication : 2010 Article en page(s) : pp. 6176–6183 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Acetone/methanol system Résumé : Displacement of the azeotropic composition of acetone/methanol system by using water as entrainer has been studied for different solvent:feed molar ratios (S/F = 1.0, 2.5, and 3.0) combined with pressure reduction, at 75.0 kPa. The vapor−liquid equilibrium data were compared to ASPEN Plus simulations using Wilson, NRTL, and UNIQUAC models. To determine the composition of the liquid and vapor phases, headspace-gas chromatography was used. For a solvent:feed molar ratio of 1.0 was obtained a complete azeotrope elimination. The obtained relative volatilities between 1.6 and 3.2 were for the assayed S/F ratios. Experimental data were well-represented by simulation with the UNIQUAC model, obtaining a vapor molar composition and temperature mean error of 0.009−0.027 and 0.80−1.70 K, respectively. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901702h
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6176–6183[article] Vapor-liquid equilibrium in extractive distillation of the acetone/methanol system using water as entrainer and pressure reduction [texte imprimé] / Diana C. Botía, Auteur ; Diana C. Riveros, Auteur ; Pablo Ortiz, Auteur . - 2010 . - pp. 6176–6183.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6176–6183
Mots-clés : Acetone/methanol system Résumé : Displacement of the azeotropic composition of acetone/methanol system by using water as entrainer has been studied for different solvent:feed molar ratios (S/F = 1.0, 2.5, and 3.0) combined with pressure reduction, at 75.0 kPa. The vapor−liquid equilibrium data were compared to ASPEN Plus simulations using Wilson, NRTL, and UNIQUAC models. To determine the composition of the liquid and vapor phases, headspace-gas chromatography was used. For a solvent:feed molar ratio of 1.0 was obtained a complete azeotrope elimination. The obtained relative volatilities between 1.6 and 3.2 were for the assayed S/F ratios. Experimental data were well-represented by simulation with the UNIQUAC model, obtaining a vapor molar composition and temperature mean error of 0.009−0.027 and 0.80−1.70 K, respectively. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901702h Exemplaires
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Titre : Simultaneous recovery of cerium and fluorine from bastnaesite leach liquor by mixtures of cyanex 923 and HEH(EHP) Type de document : texte imprimé Auteurs : Zhifeng Zhang, Auteur ; Fuqiang Guo, Auteur ; Shulan Meng, Auteur Année de publication : 2010 Article en page(s) : pp. 6184–6188 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Cerium Fluorine Cyanex923 HEH(EHP) Résumé : In this paper, studies were carried out on the extraction and recovery of cerium and fluorine by mixtures of Cyanex923 and HEH(EHP) (2-ethylhexylphosphonic mono-2-ethylhexyl ester) from a bastnaesite sulphuric leaching solution. The effects of different variables on the extraction such as the H2SO4 concentration in the leaching liquor, saturated loaded extraction, and stoichiometric quantity of H2O2 were investigated. Results indicated that the capacity of Ce(III) and F extraction with HEH(EHP) was negligible and Ce(IV) could be strongly extracted by both Cyanex923 and HEH(EHP); on the other hand, CeF3 had been produced at the stripping stage. Furthermore, appropriate technical parameters of the extraction system have been provided for industry applications and have also been confirmed by multistage countercurrent extraction. On the basis of the above results, the integrated flow of separation and recovery of rare earths from bastnaesite has been provided. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9017385
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6184–6188[article] Simultaneous recovery of cerium and fluorine from bastnaesite leach liquor by mixtures of cyanex 923 and HEH(EHP) [texte imprimé] / Zhifeng Zhang, Auteur ; Fuqiang Guo, Auteur ; Shulan Meng, Auteur . - 2010 . - pp. 6184–6188.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6184–6188
Mots-clés : Cerium Fluorine Cyanex923 HEH(EHP) Résumé : In this paper, studies were carried out on the extraction and recovery of cerium and fluorine by mixtures of Cyanex923 and HEH(EHP) (2-ethylhexylphosphonic mono-2-ethylhexyl ester) from a bastnaesite sulphuric leaching solution. The effects of different variables on the extraction such as the H2SO4 concentration in the leaching liquor, saturated loaded extraction, and stoichiometric quantity of H2O2 were investigated. Results indicated that the capacity of Ce(III) and F extraction with HEH(EHP) was negligible and Ce(IV) could be strongly extracted by both Cyanex923 and HEH(EHP); on the other hand, CeF3 had been produced at the stripping stage. Furthermore, appropriate technical parameters of the extraction system have been provided for industry applications and have also been confirmed by multistage countercurrent extraction. On the basis of the above results, the integrated flow of separation and recovery of rare earths from bastnaesite has been provided. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9017385 Exemplaires
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Titre : Effect of diluents on the synergistic solvent extraction and separation of trivalent lanthanoids with 4-benzoyl-3-phenyl-5-isoxazolone and tert-butylcalix[4]arene tetrakis(N,N-dimethyl acetamide) and structural study of Gd(III) solid complex by IR and NMR Type de document : texte imprimé Auteurs : Maria A. Petrova, Auteur ; Victoria I. Lachkova, Auteur ; Nikolay G. Vassilev, Auteur Année de publication : 2010 Article en page(s) : pp. 6189–6195 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Synergistic solvent extraction Diluents Résumé : The solvent extraction of 14 lanthanoid(III) ions from a chloride medium with acidic chelating extractant 4-benzoyl-3-phenyl-5-isoxazolone (HPBI) and tert-butylcalix[4]arene tetrakis(N,N-dimethylacetamide) (S) as a synergistic agent in C6H6 has been studied. In all cases, Ln(III) ions were extracted as Ln(PBI)3·S species. Positive values of the synergistic coefficients show that all lanthanoids were extracted synergistically upon the addition of compound S to the chelating extractant. The values of the equilibrium constant and the separation factors were calculated. The synergistic solvent extraction of five selected lanthanoid ions (La3+, Nd3+, Eu3+, Ho3+, and Lu3+) with a mixture of HPBI and S from a perchlorate medium in other diluents such as CHCl3, C2H4Cl2, and CCl4 has been studied too. It was found that the values of the equilibrium constant increased in the order CHCl3 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100328v
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6189–6195[article] Effect of diluents on the synergistic solvent extraction and separation of trivalent lanthanoids with 4-benzoyl-3-phenyl-5-isoxazolone and tert-butylcalix[4]arene tetrakis(N,N-dimethyl acetamide) and structural study of Gd(III) solid complex by IR and NMR [texte imprimé] / Maria A. Petrova, Auteur ; Victoria I. Lachkova, Auteur ; Nikolay G. Vassilev, Auteur . - 2010 . - pp. 6189–6195.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6189–6195
Mots-clés : Synergistic solvent extraction Diluents Résumé : The solvent extraction of 14 lanthanoid(III) ions from a chloride medium with acidic chelating extractant 4-benzoyl-3-phenyl-5-isoxazolone (HPBI) and tert-butylcalix[4]arene tetrakis(N,N-dimethylacetamide) (S) as a synergistic agent in C6H6 has been studied. In all cases, Ln(III) ions were extracted as Ln(PBI)3·S species. Positive values of the synergistic coefficients show that all lanthanoids were extracted synergistically upon the addition of compound S to the chelating extractant. The values of the equilibrium constant and the separation factors were calculated. The synergistic solvent extraction of five selected lanthanoid ions (La3+, Nd3+, Eu3+, Ho3+, and Lu3+) with a mixture of HPBI and S from a perchlorate medium in other diluents such as CHCl3, C2H4Cl2, and CCl4 has been studied too. It was found that the values of the equilibrium constant increased in the order CHCl3 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100328v Exemplaires
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Titre : Selective absorption of H2S from a gas mixture with CO2 by aqueous N-methyldiethanolamine in a rotating packed bed Type de document : texte imprimé Auteurs : Zhi Qian, Auteur ; Lian-Bin Xu, Auteur ; Zhen-Hu Li, Auteur Année de publication : 2010 Article en page(s) : pp. 6196–6203 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : H2S CO2 N-methyldiethanolamine Résumé : In this work, selective absorption of H2S from a gas mixture with CO2 into N-methyldiethanolamine (MDEA) is investigated experimentally and theoretically in a rotating packed bed (RPB). In the RPB, various rotating speeds, gas flow rates, liquid flow rates, and concentrations of MDEA aqueous solutions were studied by means of the evaluation of removal efficiency, selectivity, and overall volumetric mass transfer coefficient. The reaction−diffusion mass transfer model based on penetration theory for the selective absorption process is developed, accordingly. The results of experiment and model show that the uppermost function of RPB in selective absorption of H2S is to restrain the CO2 removal efficiency but sharply intensify the absorption of H2S. The mass transfer coefficient of CO2 absorption is enhanced in RPB. However, the total amount of CO2 mass transfer virtually is low because of the short gas−liquid contact time, small volume of packing, and large gas−liquid ratio within the RPB, and the CO2 removal efficiency is merely around 9.50%. For the penetration of H2S into liquid film, it is just 2.0 × 10−9 s that H2S needs to be exhausted at 10−8 m into the liquid film. And the lifetime of a liquid film in the RPB is 7 orders of magnitude bigger than this penetration time of H2S. So the reaction and mass transfer of H2S still can be completed even at the very short gas−liquid contact time within the RPB, and a high H2S removal efficiency of around 99.76% also can be achieved. In addition, a quantitative analysis based on the model, which suggests that the existence of CO2 has little effect on the absorption of H2S while the H2S has an apparent negative impact on the absorption of CO2, can be obtained for the selective absorption process. The experimental and model results have been found to be in a good agreement. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100678c
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6196–6203[article] Selective absorption of H2S from a gas mixture with CO2 by aqueous N-methyldiethanolamine in a rotating packed bed [texte imprimé] / Zhi Qian, Auteur ; Lian-Bin Xu, Auteur ; Zhen-Hu Li, Auteur . - 2010 . - pp. 6196–6203.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6196–6203
Mots-clés : H2S CO2 N-methyldiethanolamine Résumé : In this work, selective absorption of H2S from a gas mixture with CO2 into N-methyldiethanolamine (MDEA) is investigated experimentally and theoretically in a rotating packed bed (RPB). In the RPB, various rotating speeds, gas flow rates, liquid flow rates, and concentrations of MDEA aqueous solutions were studied by means of the evaluation of removal efficiency, selectivity, and overall volumetric mass transfer coefficient. The reaction−diffusion mass transfer model based on penetration theory for the selective absorption process is developed, accordingly. The results of experiment and model show that the uppermost function of RPB in selective absorption of H2S is to restrain the CO2 removal efficiency but sharply intensify the absorption of H2S. The mass transfer coefficient of CO2 absorption is enhanced in RPB. However, the total amount of CO2 mass transfer virtually is low because of the short gas−liquid contact time, small volume of packing, and large gas−liquid ratio within the RPB, and the CO2 removal efficiency is merely around 9.50%. For the penetration of H2S into liquid film, it is just 2.0 × 10−9 s that H2S needs to be exhausted at 10−8 m into the liquid film. And the lifetime of a liquid film in the RPB is 7 orders of magnitude bigger than this penetration time of H2S. So the reaction and mass transfer of H2S still can be completed even at the very short gas−liquid contact time within the RPB, and a high H2S removal efficiency of around 99.76% also can be achieved. In addition, a quantitative analysis based on the model, which suggests that the existence of CO2 has little effect on the absorption of H2S while the H2S has an apparent negative impact on the absorption of CO2, can be obtained for the selective absorption process. The experimental and model results have been found to be in a good agreement. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100678c Exemplaires
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Titre : Mass conservative solution of the population balance equation using the least-squares spectral element method Type de document : texte imprimé Auteurs : Zhengjie Zhu, Auteur ; Carlos A. Dorao, Auteur ; Hugo A. Jakobsen, Auteur Année de publication : 2010 Article en page(s) : pp. 6204–6214 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Population balance equation Mass loss Résumé : In the standard formulation of the population balance equation that consists of breakage terms, significant loss of mass is observed for the dispersed phase. This mass loss is actually caused by the inexact conservation property reflected by many breakage kernels; hence, incorrect physical interpretations of the model simulations may be drawn. In this work, a constrained method is developed enforcing mass conservation. This numerical property is accomplished by adding an extra restriction to the original population balance equation in terms of the dispersed phase continuity equation through the Lagrange multipliers strategy. The discretized system resulting from applying the method to a two-phase population balance equation problem is symmetric and pseudopositive definite. Numerical experiments are carried out simulating the motion of a two-phase mixture passing through a 2D domain. The results obtained by the modified least-squares spectral element method show that the mass is conserved everywhere in the domain with high accuracy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900710y
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6204–6214[article] Mass conservative solution of the population balance equation using the least-squares spectral element method [texte imprimé] / Zhengjie Zhu, Auteur ; Carlos A. Dorao, Auteur ; Hugo A. Jakobsen, Auteur . - 2010 . - pp. 6204–6214.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6204–6214
Mots-clés : Population balance equation Mass loss Résumé : In the standard formulation of the population balance equation that consists of breakage terms, significant loss of mass is observed for the dispersed phase. This mass loss is actually caused by the inexact conservation property reflected by many breakage kernels; hence, incorrect physical interpretations of the model simulations may be drawn. In this work, a constrained method is developed enforcing mass conservation. This numerical property is accomplished by adding an extra restriction to the original population balance equation in terms of the dispersed phase continuity equation through the Lagrange multipliers strategy. The discretized system resulting from applying the method to a two-phase population balance equation problem is symmetric and pseudopositive definite. Numerical experiments are carried out simulating the motion of a two-phase mixture passing through a 2D domain. The results obtained by the modified least-squares spectral element method show that the mass is conserved everywhere in the domain with high accuracy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900710y Exemplaires
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Titre : Thermal performance of crossflow microchannel heat exchangers Type de document : texte imprimé Auteurs : Haishan Cao, Auteur ; Guangwen Chen, Auteur ; Quan Yuan, Auteur Année de publication : 2010 Article en page(s) : pp. 6215–6220 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Crossflow microchannel heat exchanger Forced-convection transfer Résumé : Forced-convection heat transfer in a crossflow microchannel heat exchanger (MCHE) was investigated via experiment. The microchannels on the plates of the MCHE were machined using a chemical etching method from 0.4-mm-thick stainless steel plates, and the plates were bonded together by vacuum diffusion bonding. The influence of the aspect ratio of microchannels was analyzed based on MCHEs with two plates. The maximum volumetric heat-transfer coefficient using deionized (DI) water as the working fluid reached 11.1 MW m−3 K−1, with a corresponding pressure drop of En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100107s
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6215–6220[article] Thermal performance of crossflow microchannel heat exchangers [texte imprimé] / Haishan Cao, Auteur ; Guangwen Chen, Auteur ; Quan Yuan, Auteur . - 2010 . - pp. 6215–6220.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6215–6220
Mots-clés : Crossflow microchannel heat exchanger Forced-convection transfer Résumé : Forced-convection heat transfer in a crossflow microchannel heat exchanger (MCHE) was investigated via experiment. The microchannels on the plates of the MCHE were machined using a chemical etching method from 0.4-mm-thick stainless steel plates, and the plates were bonded together by vacuum diffusion bonding. The influence of the aspect ratio of microchannels was analyzed based on MCHEs with two plates. The maximum volumetric heat-transfer coefficient using deionized (DI) water as the working fluid reached 11.1 MW m−3 K−1, with a corresponding pressure drop of En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100107s Exemplaires
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Titre : Electrolyte cubic square-well equation of state for computation of the solubility CO2 and H2S in aqueous MDEA solutions Type de document : texte imprimé Auteurs : Ali Haghtalab, Auteur ; Seyed Hossein Mazloumi, Auteur Année de publication : 2010 Article en page(s) : pp. 6221–6230 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Electrolyte cubic square-well (eCSW) equation Résumé : The electrolyte cubic square-well (eCSW) equation of state [Haghtalab, A.; Mazloumi, S. H. Fluid Phase Equilib. 2009, 285, 96−104] is applied to study the solubility of CO2 and H2S in aqueous N-methyldiethanolamine (MDEA) solutions in the wide range of concentration, pressure, temperature, and acid gas loading. This electrolyte equation of state is composed of the mean spherical approximation (MSA) theory, the Born equation, and a cubic square-well equation of state (SWEOS). Using eCSW EOS, calculations of the vapor−liquid equilibria are performed for the binaries of water−alkanolamine and acid gas−water systems so that the binary molecular interaction parameters, kij in the combing rule of the EOS, are optimized for the CO2−H2O, H2S−H2O, and MDEA−H2O systems. Having the binary interaction parameters between the molecular species, the solubility of CO2 and H2S in the aqueous solution of MDEA is calculated by the use of the simultaneous vapor−liquid equilibria and chemical equilibria algorithm. Also, to improve the calculation of the solubility of the acid gases in the ternary CO2−MDEA−H2O, H2S−MDEA−H2O systems, some of the binary interaction parameters among ionic and molecular species are optimized using the same EOS approach. Influence of the binary interaction parameters on the performance of the SWEOS is investigated using a large number of experimental data points of the acid gas−aqueous MDEA solutions. Moreover, the solubilities of mixed H2S and CO2 gases in aqueous MDEA solution are predicted. The results demonstrate that the eCSW EOS is able to represent the solubility data of both ternary and quaternary aqueous alkanolamine systems with very good accuracy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901664k
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6221–6230[article] Electrolyte cubic square-well equation of state for computation of the solubility CO2 and H2S in aqueous MDEA solutions [texte imprimé] / Ali Haghtalab, Auteur ; Seyed Hossein Mazloumi, Auteur . - 2010 . - pp. 6221–6230.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6221–6230
Mots-clés : Electrolyte cubic square-well (eCSW) equation Résumé : The electrolyte cubic square-well (eCSW) equation of state [Haghtalab, A.; Mazloumi, S. H. Fluid Phase Equilib. 2009, 285, 96−104] is applied to study the solubility of CO2 and H2S in aqueous N-methyldiethanolamine (MDEA) solutions in the wide range of concentration, pressure, temperature, and acid gas loading. This electrolyte equation of state is composed of the mean spherical approximation (MSA) theory, the Born equation, and a cubic square-well equation of state (SWEOS). Using eCSW EOS, calculations of the vapor−liquid equilibria are performed for the binaries of water−alkanolamine and acid gas−water systems so that the binary molecular interaction parameters, kij in the combing rule of the EOS, are optimized for the CO2−H2O, H2S−H2O, and MDEA−H2O systems. Having the binary interaction parameters between the molecular species, the solubility of CO2 and H2S in the aqueous solution of MDEA is calculated by the use of the simultaneous vapor−liquid equilibria and chemical equilibria algorithm. Also, to improve the calculation of the solubility of the acid gases in the ternary CO2−MDEA−H2O, H2S−MDEA−H2O systems, some of the binary interaction parameters among ionic and molecular species are optimized using the same EOS approach. Influence of the binary interaction parameters on the performance of the SWEOS is investigated using a large number of experimental data points of the acid gas−aqueous MDEA solutions. Moreover, the solubilities of mixed H2S and CO2 gases in aqueous MDEA solution are predicted. The results demonstrate that the eCSW EOS is able to represent the solubility data of both ternary and quaternary aqueous alkanolamine systems with very good accuracy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901664k Exemplaires
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Titre : Experimental study of diffusive tortuosity of liquid-saturated consolidated porous media Type de document : texte imprimé Auteurs : Zhaowen Li, Auteur ; Mingzhe Dong, Auteur Année de publication : 2010 Article en page(s) : pp. 6231–6237 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Diffusive tortuosity Liquid-saturated porous media Résumé : Diffusive tortuosity factor is one of the key parameters in modeling solute diffusion in liquid-saturated porous media. However, the determination of diffusive tortuosity factor has to involve a diffusion process in liquid-saturated porous media, which was usually found complicated in laboratories. The incorrect use of diffusive tortuosity factor may cause significant errors in certain circumstances. This paper presents a method to evaluate the diffusive tortuosity factors for liquid-saturated consolidated porous media, i.e., sandstones, which are the typical porous media commonly encountered in contaminant transport in underground water and gas migration in liquid-saturated reservoirs. The proposed method applies two specific experiments to determine the diffusion coefficient in bulk liquid phase and the effective diffusion coefficient in liquid-saturated porous media, respectively. Diffusive tortuosity factor of the porous media is obtained by comparing the effective diffusion coefficient in porous media to the diffusion coefficient in bulk liquid. This study provides a procedure to evaluate the diffusive tortuosity factor for consolidated porous media and also the measured values of diffusive tortuosity factors for selected sandstone samples which can be used as input data for further studies. Another application of the proposed method is to determine the diffusion coefficient in bulk liquid phase for CO2 from the measured effective diffusion coefficients in porous media. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901765d
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6231–6237[article] Experimental study of diffusive tortuosity of liquid-saturated consolidated porous media [texte imprimé] / Zhaowen Li, Auteur ; Mingzhe Dong, Auteur . - 2010 . - pp. 6231–6237.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6231–6237
Mots-clés : Diffusive tortuosity Liquid-saturated porous media Résumé : Diffusive tortuosity factor is one of the key parameters in modeling solute diffusion in liquid-saturated porous media. However, the determination of diffusive tortuosity factor has to involve a diffusion process in liquid-saturated porous media, which was usually found complicated in laboratories. The incorrect use of diffusive tortuosity factor may cause significant errors in certain circumstances. This paper presents a method to evaluate the diffusive tortuosity factors for liquid-saturated consolidated porous media, i.e., sandstones, which are the typical porous media commonly encountered in contaminant transport in underground water and gas migration in liquid-saturated reservoirs. The proposed method applies two specific experiments to determine the diffusion coefficient in bulk liquid phase and the effective diffusion coefficient in liquid-saturated porous media, respectively. Diffusive tortuosity factor of the porous media is obtained by comparing the effective diffusion coefficient in porous media to the diffusion coefficient in bulk liquid. This study provides a procedure to evaluate the diffusive tortuosity factor for consolidated porous media and also the measured values of diffusive tortuosity factors for selected sandstone samples which can be used as input data for further studies. Another application of the proposed method is to determine the diffusion coefficient in bulk liquid phase for CO2 from the measured effective diffusion coefficients in porous media. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901765d Exemplaires
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Titre : Solubility of phenanthrene in ternary mixtures of C1−C4 alcohols at 298.2 K Type de document : texte imprimé Auteurs : Mohammad A. A. Fakhree, Auteur ; William E. Acree Jr., Auteur ; Abolghasem Jouyban, Auteur Année de publication : 2010 Article en page(s) : pp. 6238–6242 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Phenanthrene Ternary mixtures Résumé : Solubility of phenanthrene in ternary mixtures of ethanol +1-propanol + methanol, ethanol + 1-propanol + 2-propanol, 1-butanol + methanol + 2-propanol, 1-butanol + ethanol + 1-propanol, and 1-butanol + 1-propanol + methanol are reported. Five numerical methods were used to predict solubility of phenanthrene in studied ternary mixtures, and the mean relative deviation (MRD) was used as a criterion of error. The MRD values for studied mixtures of alcohols were 3.7%, 18.0%, 12.0%, 99.7%, and 12.7%, respectively, for methods I−V. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100002y
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6238–6242[article] Solubility of phenanthrene in ternary mixtures of C1−C4 alcohols at 298.2 K [texte imprimé] / Mohammad A. A. Fakhree, Auteur ; William E. Acree Jr., Auteur ; Abolghasem Jouyban, Auteur . - 2010 . - pp. 6238–6242.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6238–6242
Mots-clés : Phenanthrene Ternary mixtures Résumé : Solubility of phenanthrene in ternary mixtures of ethanol +1-propanol + methanol, ethanol + 1-propanol + 2-propanol, 1-butanol + methanol + 2-propanol, 1-butanol + ethanol + 1-propanol, and 1-butanol + 1-propanol + methanol are reported. Five numerical methods were used to predict solubility of phenanthrene in studied ternary mixtures, and the mean relative deviation (MRD) was used as a criterion of error. The MRD values for studied mixtures of alcohols were 3.7%, 18.0%, 12.0%, 99.7%, and 12.7%, respectively, for methods I−V. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100002y Exemplaires
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Titre : Mineralization of trace nitro/chloro/methyl/amino-aromatic contaminants in wastewaters by advanced oxidation processes Type de document : texte imprimé Auteurs : Wenjuan Huang, Auteur ; Yuanhui Ji, Auteur ; Zhuhong Yang, Auteur Année de publication : 2010 Article en page(s) : pp. 6243–6249 Note générale : chamical angineering Langues : Anglais (eng) Mots-clés : Aromatic contaminants Mineralization Résumé : It has great significance to investigate the degradation of aromatic contaminants as they are highly carcinogenic and nondegradable pollutants in drinking water. In this paper, the mineralization orders of the representative nitro/chloro/methyl/amino-aromatic contaminants with oxidants (·OH, H2O2, ·O−, O2,O3) in advanced oxidation processes (AOPs) are investigated based on the calculated standard molar Gibbs free energy changes of reaction (ΔrGm0) and the results are consistent with those from previous experimental results, electrophilic substitution orientation rules of the Hammett equation, and predicted results with a quantitative structure−activity relationship (QSAR). In addition, the quantitative function relationship between the degradation rate (r) of the aromatic contaminants and the thermodynamic driving force (ΔrGm0) is analyzed in order to investigate the degradation kinetics more rigorously. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100116c
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6243–6249[article] Mineralization of trace nitro/chloro/methyl/amino-aromatic contaminants in wastewaters by advanced oxidation processes [texte imprimé] / Wenjuan Huang, Auteur ; Yuanhui Ji, Auteur ; Zhuhong Yang, Auteur . - 2010 . - pp. 6243–6249.
chamical angineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6243–6249
Mots-clés : Aromatic contaminants Mineralization Résumé : It has great significance to investigate the degradation of aromatic contaminants as they are highly carcinogenic and nondegradable pollutants in drinking water. In this paper, the mineralization orders of the representative nitro/chloro/methyl/amino-aromatic contaminants with oxidants (·OH, H2O2, ·O−, O2,O3) in advanced oxidation processes (AOPs) are investigated based on the calculated standard molar Gibbs free energy changes of reaction (ΔrGm0) and the results are consistent with those from previous experimental results, electrophilic substitution orientation rules of the Hammett equation, and predicted results with a quantitative structure−activity relationship (QSAR). In addition, the quantitative function relationship between the degradation rate (r) of the aromatic contaminants and the thermodynamic driving force (ΔrGm0) is analyzed in order to investigate the degradation kinetics more rigorously. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100116c Exemplaires
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Titre : Equivalence of the McAllister and heric equations for correlating the liquid viscosity of multicomponent mixtures Type de document : texte imprimé Auteurs : Gustavo A. Iglesias-Silva, Auteur ; Kenneth R. Hall, Auteur Année de publication : 2010 Article en page(s) : pp. 6250–6254 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Correlating liquid kinematic viscosities McAllister equations Heric Résumé : This paper demonstrates the equivalence between two equations for correlating liquid kinematic viscosities: the Heric and McAllister equations. For ternary and multicomponent mixtures, the only difference is in the ternary interaction term. If this term is constant, both equations correlate the viscosity data identically. This approach can prove the equivalence of the Nissan and Grunberg equation and the Frenkel equation to correlate the dynamic viscosity of liquid mixtures. Examples are included for binary and ternary mixtures. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1002763
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6250–6254[article] Equivalence of the McAllister and heric equations for correlating the liquid viscosity of multicomponent mixtures [texte imprimé] / Gustavo A. Iglesias-Silva, Auteur ; Kenneth R. Hall, Auteur . - 2010 . - pp. 6250–6254.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6250–6254
Mots-clés : Correlating liquid kinematic viscosities McAllister equations Heric Résumé : This paper demonstrates the equivalence between two equations for correlating liquid kinematic viscosities: the Heric and McAllister equations. For ternary and multicomponent mixtures, the only difference is in the ternary interaction term. If this term is constant, both equations correlate the viscosity data identically. This approach can prove the equivalence of the Nissan and Grunberg equation and the Frenkel equation to correlate the dynamic viscosity of liquid mixtures. Examples are included for binary and ternary mixtures. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1002763 Exemplaires
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Titre : Hydrogen-transfer reduction of ketones into corresponding alcohols using formic acid as a hydrogen donor without a metal catalyst in high-temperature water Type de document : texte imprimé Auteurs : Zheng Shen, Auteur ; Yalei Zhang, Auteur ; Fangming Jin, Auteur Année de publication : 2010 Article en page(s) : pp. 6255–6259 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hydrothermal reactions Hydrogen transferring Ketones Résumé : In hydrothermal reactions at 260−300 °C, ketones can be reduced into corresponding alcohols by hydrogen transferring from another alcohols or formic acid without a metal catalyst. When using formic acid as a hydrogen donor, the yield of alcohols at respective better conditions was considerably high at a much lower ratio of hydrogen source to ketones compared to traditional Meerwein−Poundrof−Verley (MPV) reduction, reaching 60% for isopropanol from acetone and 70% for lactic acid from pyruvic acid. The proposed possible mechanism for the hydrogen transfer reduction of ketones in high-temperature water (HTW) is similar to the pathway elucidated in the traditional MPV reduction via a transition state. Rather than metal-alkoxides catalysts in MPV reduction, water molecules in HTW as a catalyst may directly participate in the transition state by making a hydrogen-bond ring network with three molecules, that is, ketone, formic acid, and water. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100598a
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6255–6259[article] Hydrogen-transfer reduction of ketones into corresponding alcohols using formic acid as a hydrogen donor without a metal catalyst in high-temperature water [texte imprimé] / Zheng Shen, Auteur ; Yalei Zhang, Auteur ; Fangming Jin, Auteur . - 2010 . - pp. 6255–6259.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6255–6259
Mots-clés : Hydrothermal reactions Hydrogen transferring Ketones Résumé : In hydrothermal reactions at 260−300 °C, ketones can be reduced into corresponding alcohols by hydrogen transferring from another alcohols or formic acid without a metal catalyst. When using formic acid as a hydrogen donor, the yield of alcohols at respective better conditions was considerably high at a much lower ratio of hydrogen source to ketones compared to traditional Meerwein−Poundrof−Verley (MPV) reduction, reaching 60% for isopropanol from acetone and 70% for lactic acid from pyruvic acid. The proposed possible mechanism for the hydrogen transfer reduction of ketones in high-temperature water (HTW) is similar to the pathway elucidated in the traditional MPV reduction via a transition state. Rather than metal-alkoxides catalysts in MPV reduction, water molecules in HTW as a catalyst may directly participate in the transition state by making a hydrogen-bond ring network with three molecules, that is, ketone, formic acid, and water. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100598a Exemplaires
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