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Vol. 51 N° 36 - Septembre 2012 [texte imprimé] . - 2012 . - p. 11593-11818 : ill. ; 28 cm. Chemical engineering Langues : Anglais (eng)
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Ajouter le résultat dans votre panierBromination of deactivated aromatic compounds with sodium bromide / sodium periodate under mild acidic conditions / Lalit Kumar in Industrial & engineering chemistry research, Vol. 51 N° 36 (Septembre 2012)
Titre : Bromination of deactivated aromatic compounds with sodium bromide / sodium periodate under mild acidic conditions Type de document : texte imprimé Auteurs : Lalit Kumar, Auteur ; Tanu Mahajan, Auteur ; D. D. Agarwal, Auteur Année de publication : 2012 Article en page(s) : pp. 11593-11597 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Bromination Résumé : A new, simple, and practical aromatic bromination process is disclosed wherein NaBr/NaIO4 combination in acidic medium was efficiently utilized for the first time in the bromination of deactivated aromatic compounds, thus, affording the corresponding bromo-derivatives of deactivated aromatics in good yields and purity. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350323
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11593-11597[article] Bromination of deactivated aromatic compounds with sodium bromide / sodium periodate under mild acidic conditions [texte imprimé] / Lalit Kumar, Auteur ; Tanu Mahajan, Auteur ; D. D. Agarwal, Auteur . - 2012 . - pp. 11593-11597.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11593-11597
Mots-clés : Bromination Résumé : A new, simple, and practical aromatic bromination process is disclosed wherein NaBr/NaIO4 combination in acidic medium was efficiently utilized for the first time in the bromination of deactivated aromatic compounds, thus, affording the corresponding bromo-derivatives of deactivated aromatics in good yields and purity. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350323 Exemplaires
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Titre : H2SO4 - catalyzed hydrothermal pretreatment of triploid poplar to enhance enzymatic hydrolysis Type de document : texte imprimé Auteurs : Haiyan Yang, Auteur ; Kun Wang, Auteur ; Feng Xu, Auteur Année de publication : 2012 Article en page(s) : pp. 11598-11604 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Hydrolysis Pretreatment Catalytic reaction Résumé : Sealed structure of plant biomass resists assault on cellulose from enzymatic deconstruction. In this study, pretreatments of triploid poplar were conducted with 0.5 wt % H2SO4 at various temperatures (100―200 °C) to loosen the intricate structure. The effect of temperature on cellulose structure and enzymatic digestibility was evaluated. The results indicated that the effective removal of hemicelluloses and amorphous cellulose incurred the increment of crystalline indices of residues. Companied with the degradation of carbohydrates, inhibitory compounds were accumulated with the increasing severity. On the whole, 120 °C was considered as the optimum temperature by taking the balance between substrate digestibility and recovery into account. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350324
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11598-11604[article] H2SO4 - catalyzed hydrothermal pretreatment of triploid poplar to enhance enzymatic hydrolysis [texte imprimé] / Haiyan Yang, Auteur ; Kun Wang, Auteur ; Feng Xu, Auteur . - 2012 . - pp. 11598-11604.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11598-11604
Mots-clés : Hydrolysis Pretreatment Catalytic reaction Résumé : Sealed structure of plant biomass resists assault on cellulose from enzymatic deconstruction. In this study, pretreatments of triploid poplar were conducted with 0.5 wt % H2SO4 at various temperatures (100―200 °C) to loosen the intricate structure. The effect of temperature on cellulose structure and enzymatic digestibility was evaluated. The results indicated that the effective removal of hemicelluloses and amorphous cellulose incurred the increment of crystalline indices of residues. Companied with the degradation of carbohydrates, inhibitory compounds were accumulated with the increasing severity. On the whole, 120 °C was considered as the optimum temperature by taking the balance between substrate digestibility and recovery into account. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350324 Exemplaires
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Titre : Investigation +into a pour point depressant for shengli crude oil Type de document : texte imprimé Auteurs : Long Fang, Auteur ; Xiaodong Zhang, Auteur ; Jinhai Ma, Auteur Année de publication : 2012 Article en page(s) : pp. 11605-11612 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Crude oil Résumé : A new-style pour point depressant (PPD) for crude oil was prepared by mixing the aminated copolymer and the composite commercial ethylene―vinyl acetate copolymers (EVA) in fixed proportion. The aminated copolymer was synthesized by amination of terpolymer copolymerized with monomers octadecyl acrylate, maleic anhydride, and vinyl acetate. Moreover, the aminated copolymer was characterized by Fourier transform infrared (FTIR) spectroscopy, 1H nuclear magnetic resonance (1H NMR), and gel permeation chromatography (GPC). The interaction between components of the crude oil and the PPD was investigated by FTIR, differential scanning calorimetry (DSC), and cross-polarized light microscopy. The results showed that the PPD could form asphaltene-PPD-resin agglomerates. The new agglomerates became the efficient nucleator of the crude oil beneficiated with PPD. They changed the process of wax crystallization and greatly depressed the pour point of the crude oil. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350325
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11605-11612[article] Investigation +into a pour point depressant for shengli crude oil [texte imprimé] / Long Fang, Auteur ; Xiaodong Zhang, Auteur ; Jinhai Ma, Auteur . - 2012 . - pp. 11605-11612.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11605-11612
Mots-clés : Crude oil Résumé : A new-style pour point depressant (PPD) for crude oil was prepared by mixing the aminated copolymer and the composite commercial ethylene―vinyl acetate copolymers (EVA) in fixed proportion. The aminated copolymer was synthesized by amination of terpolymer copolymerized with monomers octadecyl acrylate, maleic anhydride, and vinyl acetate. Moreover, the aminated copolymer was characterized by Fourier transform infrared (FTIR) spectroscopy, 1H nuclear magnetic resonance (1H NMR), and gel permeation chromatography (GPC). The interaction between components of the crude oil and the PPD was investigated by FTIR, differential scanning calorimetry (DSC), and cross-polarized light microscopy. The results showed that the PPD could form asphaltene-PPD-resin agglomerates. The new agglomerates became the efficient nucleator of the crude oil beneficiated with PPD. They changed the process of wax crystallization and greatly depressed the pour point of the crude oil. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350325 Exemplaires
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Titre : Identification of the molecular species responsible for the initiation of amorphous dithiazine formation in laboratory studies of 1,3,5 - tris (hydroxyethyl) - hexahydro - s - triazine as a hydrogen sulfide scavenger Type de document : texte imprimé Auteurs : Grahame N. Taylor, Auteur ; Philippe Prince, Auteur ; Ron Matherly, Auteur Année de publication : 2012 Article en page(s) : pp. 11613-11617 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Hydrogen sulfides Résumé : Amorphous dithiazine is produced from a solution of tris-(2-hyroxyethyl)-hexahydro-s-triazine (I) that is heavily consumed by hydrogen sulfide (H2S). Previously, it has been reported that the chemical structure of amorphous dithiazine is a polymeric structure which involves opening of the dithiazine ring. Evidence is presented here that the first step in this polymerization reaction is conversion of the terminal hydroxyl functionality into a terminal thiol. Thereafter, the thiol initiates the ring opening of the dithiazine to yield a polymeric, highly insoluble material. It has been observed that the critical chemical species in the initiation of this chain reaction is the bisulfide anion. This bisulfide anion is produced from the reaction of H2S with ethanolamine liberated in the sulfur insertion reaction undergone by tris-(2-hyroxyethyl)-hexahydro-s-triazine (I). This process has been artificially induced by the reaction of monomeric or crystalline 5-hydroxyethyldithiazine (II) and ethanolammonium hydrosulfide. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350326
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11613-11617[article] Identification of the molecular species responsible for the initiation of amorphous dithiazine formation in laboratory studies of 1,3,5 - tris (hydroxyethyl) - hexahydro - s - triazine as a hydrogen sulfide scavenger [texte imprimé] / Grahame N. Taylor, Auteur ; Philippe Prince, Auteur ; Ron Matherly, Auteur . - 2012 . - pp. 11613-11617.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11613-11617
Mots-clés : Hydrogen sulfides Résumé : Amorphous dithiazine is produced from a solution of tris-(2-hyroxyethyl)-hexahydro-s-triazine (I) that is heavily consumed by hydrogen sulfide (H2S). Previously, it has been reported that the chemical structure of amorphous dithiazine is a polymeric structure which involves opening of the dithiazine ring. Evidence is presented here that the first step in this polymerization reaction is conversion of the terminal hydroxyl functionality into a terminal thiol. Thereafter, the thiol initiates the ring opening of the dithiazine to yield a polymeric, highly insoluble material. It has been observed that the critical chemical species in the initiation of this chain reaction is the bisulfide anion. This bisulfide anion is produced from the reaction of H2S with ethanolamine liberated in the sulfur insertion reaction undergone by tris-(2-hyroxyethyl)-hexahydro-s-triazine (I). This process has been artificially induced by the reaction of monomeric or crystalline 5-hydroxyethyldithiazine (II) and ethanolammonium hydrosulfide. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350326 Exemplaires
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Titre : Irregularities in product distribution of fischer – tropsch synthesis due to experimental artifact Type de document : texte imprimé Auteurs : Junhu Gao, Auteur ; Baoshan Wu, Auteur ; Liping Zhou, Auteur Année de publication : 2012 Article en page(s) : pp. 11618-11628 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Fischer Tropsch synthesis Résumé : Experimental product distribution of Fischer—Tropsch synthesis frequently presents notable deviations from the typical double-a Anderson―Schulz—Flory pattern: bump or dip around the breaking carbon number, positive or negative deviation for heavy hydrocarbons. These irregularities were studied experimentally in a fixed-bed reactor over an industrial Fe/ Mn catalyst, and theoretically by a product separation model based on Aspen Plus software. First, it was found that the unsteady state of reaction condition or improper gas chromatograph procedure could lead to deviation for heavy hydrocarbon distribution. Second, the bump near the breaking carbon number could be attributed to the accumulation of water in hot trap, which leads to an inaccurate measurement of the wax amount. This irregularity can be eliminated by selecting either a higher temperature or a lower pressure of the hot trap. Third, vaporization or flash loss of the oil sample during product collection could result in dip in light hydrocarbon distribution. High syngas conversion levels should be avoided for accurate data acquirement. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350327
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11618-11628[article] Irregularities in product distribution of fischer – tropsch synthesis due to experimental artifact [texte imprimé] / Junhu Gao, Auteur ; Baoshan Wu, Auteur ; Liping Zhou, Auteur . - 2012 . - pp. 11618-11628.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11618-11628
Mots-clés : Fischer Tropsch synthesis Résumé : Experimental product distribution of Fischer—Tropsch synthesis frequently presents notable deviations from the typical double-a Anderson―Schulz—Flory pattern: bump or dip around the breaking carbon number, positive or negative deviation for heavy hydrocarbons. These irregularities were studied experimentally in a fixed-bed reactor over an industrial Fe/ Mn catalyst, and theoretically by a product separation model based on Aspen Plus software. First, it was found that the unsteady state of reaction condition or improper gas chromatograph procedure could lead to deviation for heavy hydrocarbon distribution. Second, the bump near the breaking carbon number could be attributed to the accumulation of water in hot trap, which leads to an inaccurate measurement of the wax amount. This irregularity can be eliminated by selecting either a higher temperature or a lower pressure of the hot trap. Third, vaporization or flash loss of the oil sample during product collection could result in dip in light hydrocarbon distribution. High syngas conversion levels should be avoided for accurate data acquirement. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350327 Exemplaires
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Titre : Agglomeration detection in horizontal stirred bed reactor based on autoregression model by acoustic emission signals Type de document : texte imprimé Auteurs : Yefeng Zhou, Auteur ; Zhengliang Huang, Auteur ; Ren Congjing, Auteur Année de publication : 2012 Article en page(s) : pp. 11629-11635 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Acoustic emission Modeling Stirred tank reactor Agglomeration Résumé : Agglomeration occurring in horizontal stirred bed reactors (HSBR) for polyolefin production has negative impacts on the efficiency of the reactor operation and may sometimes lead to unscheduled shutdown of the plant. In this paper, an autoregression (AR) model based on acoustic emission (AE) technique has been proposed to establish the qualitative relationship between AE signals and agglomeration in the HSBR. In this method, the frequency of AE signal varies with particles of different sizes striking the reactor walls. From the cold model experiments, it was found that AR power spectrum became fluctuant after the addition of agglomerations into laboratorial scale HSBR, and meanwhile the low frequency band energy ratio and the variance of AE signals kept rising. Furthermore, this AE-based AR model was also successfully applied to detect the agglomeration in an industrial HSBR unit, showing that the method could monitor agglomerations in an environmentally friendly manner and with fairly good accuracy. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350328
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11629-11635[article] Agglomeration detection in horizontal stirred bed reactor based on autoregression model by acoustic emission signals [texte imprimé] / Yefeng Zhou, Auteur ; Zhengliang Huang, Auteur ; Ren Congjing, Auteur . - 2012 . - pp. 11629-11635.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11629-11635
Mots-clés : Acoustic emission Modeling Stirred tank reactor Agglomeration Résumé : Agglomeration occurring in horizontal stirred bed reactors (HSBR) for polyolefin production has negative impacts on the efficiency of the reactor operation and may sometimes lead to unscheduled shutdown of the plant. In this paper, an autoregression (AR) model based on acoustic emission (AE) technique has been proposed to establish the qualitative relationship between AE signals and agglomeration in the HSBR. In this method, the frequency of AE signal varies with particles of different sizes striking the reactor walls. From the cold model experiments, it was found that AR power spectrum became fluctuant after the addition of agglomerations into laboratorial scale HSBR, and meanwhile the low frequency band energy ratio and the variance of AE signals kept rising. Furthermore, this AE-based AR model was also successfully applied to detect the agglomeration in an industrial HSBR unit, showing that the method could monitor agglomerations in an environmentally friendly manner and with fairly good accuracy. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350328 Exemplaires
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Titre : Mass transfer at a vertical oscillating screen stack in relation to catalytic and electrochemical reactor design Type de document : texte imprimé Auteurs : M. H. Abdel-Aziz, Auteur ; I. Nirdosh, Auteur ; G. H. Sedahmed, Auteur Année de publication : 2012 Article en page(s) : pp. 11636-11642 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Design Electrochemical reactor Catalytic reaction Mass transfer Résumé : The aim of the present work is to improve the performance of the parallel plate catalytic and electrochemical reactor in conducting diffusion controlled reactions by using parallel oscillating vertical arrays of closely packed screens. To this end, rates of mass transfer at oscillating vertical single screen and arrays of closely packed screens were studied by measuring the limiting current of the cathodic deposition of copper from acidified copper sulfate. Variables studied were amplitude and frequency of vibration, screen mesh number, and number of screens per stack. The mass transfer data at a single vibrating screen were correlated by the equation: Sh = 0.73Sc0.33Re0.38v. Increasing mesh number of the screen was found to increase the mass transfer coefficient, while increasing the number of screens per stack decreased the mass transfer coefficient below single screen value. The enhancement ratio between oscillating screen array and oscillating vertical plate (the volumetric mass transfer coefficient ratio) ranged from 11.7 to 27.87 depending on the operating conditions. Electrical energy consumption of the present reactor was found to be lower than the value reported in the literature for electrowinning of copper using traditional parallel plate reactor. In view of this, the possibility of using oscillating vertical screen stack in building high space-time yield modular parallel plate electrochemical reactor suitable for wastewater treatment, electroorganic synthesis, and electrochemical energy storage via redox cells was noted. Also, the possibility of using the present geometry in building catalytic reactors suitable for conducting diffusion controlled liquid―solid reaction was highlighted. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350329
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11636-11642[article] Mass transfer at a vertical oscillating screen stack in relation to catalytic and electrochemical reactor design [texte imprimé] / M. H. Abdel-Aziz, Auteur ; I. Nirdosh, Auteur ; G. H. Sedahmed, Auteur . - 2012 . - pp. 11636-11642.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11636-11642
Mots-clés : Design Electrochemical reactor Catalytic reaction Mass transfer Résumé : The aim of the present work is to improve the performance of the parallel plate catalytic and electrochemical reactor in conducting diffusion controlled reactions by using parallel oscillating vertical arrays of closely packed screens. To this end, rates of mass transfer at oscillating vertical single screen and arrays of closely packed screens were studied by measuring the limiting current of the cathodic deposition of copper from acidified copper sulfate. Variables studied were amplitude and frequency of vibration, screen mesh number, and number of screens per stack. The mass transfer data at a single vibrating screen were correlated by the equation: Sh = 0.73Sc0.33Re0.38v. Increasing mesh number of the screen was found to increase the mass transfer coefficient, while increasing the number of screens per stack decreased the mass transfer coefficient below single screen value. The enhancement ratio between oscillating screen array and oscillating vertical plate (the volumetric mass transfer coefficient ratio) ranged from 11.7 to 27.87 depending on the operating conditions. Electrical energy consumption of the present reactor was found to be lower than the value reported in the literature for electrowinning of copper using traditional parallel plate reactor. In view of this, the possibility of using oscillating vertical screen stack in building high space-time yield modular parallel plate electrochemical reactor suitable for wastewater treatment, electroorganic synthesis, and electrochemical energy storage via redox cells was noted. Also, the possibility of using the present geometry in building catalytic reactors suitable for conducting diffusion controlled liquid―solid reaction was highlighted. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350329 Exemplaires
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Titre : Micromixing Efficiency of a Spinning Disk Reactor Type de document : texte imprimé Auteurs : Nikolas C. Jacobsen, Auteur ; Olaf Hinrichsen, Auteur Année de publication : 2012 Article en page(s) : pp. 11643-11652 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Reactor Micromixing Résumé : This work presents the experimental investigation of the micromixing characteristics of a spinning disk reactor (SDR) by using a system of competitive parallel reactions, particularly the iodide―iodate reaction (Villermaux―Dushman reaction). The objective of this study is to analyze the influence of various operating parameters such as the rotational speed of the disk, the feed location, and the surface structure of the disk on the mixing quality. It is shown that the micromixing efficiency can be particularly controlled by variation of the disk speed. These results are further validated by the investigation of the precipitation reaction of barium sulfate. This synthesis offers fast reaction kinetics with induction times in the range of milliseconds, resulting in a mixing time which lies in the range of this for efficient mixers like microreactors. The use of the spinning disk technology enables one to produce particles continuously with controllable mean sizes down to 27 nm, without the risk of fouling or blocking. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350330
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11643-11652[article] Micromixing Efficiency of a Spinning Disk Reactor [texte imprimé] / Nikolas C. Jacobsen, Auteur ; Olaf Hinrichsen, Auteur . - 2012 . - pp. 11643-11652.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11643-11652
Mots-clés : Reactor Micromixing Résumé : This work presents the experimental investigation of the micromixing characteristics of a spinning disk reactor (SDR) by using a system of competitive parallel reactions, particularly the iodide―iodate reaction (Villermaux―Dushman reaction). The objective of this study is to analyze the influence of various operating parameters such as the rotational speed of the disk, the feed location, and the surface structure of the disk on the mixing quality. It is shown that the micromixing efficiency can be particularly controlled by variation of the disk speed. These results are further validated by the investigation of the precipitation reaction of barium sulfate. This synthesis offers fast reaction kinetics with induction times in the range of milliseconds, resulting in a mixing time which lies in the range of this for efficient mixers like microreactors. The use of the spinning disk technology enables one to produce particles continuously with controllable mean sizes down to 27 nm, without the risk of fouling or blocking. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350330 Exemplaires
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Titre : Kinetics study for ion - exchange - resin catalyzed hydrolysis of methyl glycolate Type de document : texte imprimé Auteurs : Yan Xu, Auteur ; Wenjing Dou, Auteur ; Yujun Zhao, Auteur Année de publication : 2012 Article en page(s) : pp. 11653-11658 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Hydrolysis Catalytic reaction Ion exchange resin Kinetics Résumé : The hydrolysis of methyl glycolate catalyzed by commercial cation-exchange resin was studied in a stirred tank batch reactor. It was found that 001×7 resin was an effective catalyst for the hydrolysis of methyl glycolate. The effects of catalyst loading, initial reactant ratio and temperature have been examined in detail. The kinetics of glycolate hydrolysis was evaluated by the use of the pseudohomogeneous model, which was found to represent the kinetics fairly well, due to the total dissociation of the active sulfonic acid group in swollen polymer resin in the presence of water. The kinetics was expressed in terms of activities and the activity coefficients were estimated by using the group contribution method UNIFAC. The activation energy was found to be 59.26 kJ/mol for 001x7 resin, indicating surface reaction is the rate-controlling step. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350331
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11653-11658[article] Kinetics study for ion - exchange - resin catalyzed hydrolysis of methyl glycolate [texte imprimé] / Yan Xu, Auteur ; Wenjing Dou, Auteur ; Yujun Zhao, Auteur . - 2012 . - pp. 11653-11658.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11653-11658
Mots-clés : Hydrolysis Catalytic reaction Ion exchange resin Kinetics Résumé : The hydrolysis of methyl glycolate catalyzed by commercial cation-exchange resin was studied in a stirred tank batch reactor. It was found that 001×7 resin was an effective catalyst for the hydrolysis of methyl glycolate. The effects of catalyst loading, initial reactant ratio and temperature have been examined in detail. The kinetics of glycolate hydrolysis was evaluated by the use of the pseudohomogeneous model, which was found to represent the kinetics fairly well, due to the total dissociation of the active sulfonic acid group in swollen polymer resin in the presence of water. The kinetics was expressed in terms of activities and the activity coefficients were estimated by using the group contribution method UNIFAC. The activation energy was found to be 59.26 kJ/mol for 001x7 resin, indicating surface reaction is the rate-controlling step. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350331 Exemplaires
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Titre : Characterization of solid acid catalysts and their reactivity in the glycolysis of poly(ethylene terephthalate) Type de document : texte imprimé Auteurs : Minli Zhu, Auteur ; Zengxi Li, Auteur ; Qian Wang, Auteur Année de publication : 2012 Article en page(s) : pp. 11659-11666 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Chemical reactivity Acid catalysis Résumé : Glycolysis of poly(ethylene terephthalate) with ethylene glycol was carried out with the catalysts of sulfated cobalt oxide (SO42―/Co3O4) and zinc-modified sulfated cobalt oxide (SO42―/Co―Zn―O). The catalysts prepared at different calcination temperatures have been characterized by various techniques. These techniques include X-ray diffraction, Raman spectrum, gas adsorption analysis, NH3-temperature programmed desorption, and IR spectroscopy of pyridine adsorption. The performances of these catalysts on the depolymerization of PET under mild conditions were studied, and relationships between the catalysts' textural properties, the surface acidity, and the catalytic activity have been investigated. The experimental results showed that the catalytic activity on glycolysis of PET was significantly improved by the catalysts of binary sulfur oxides of SO42―/Co―Zn―O. The conversion of PET obtained on SO42―/Co―Zn―O-300 °C was 96%, and the selectivity of BHET was 75%, after 3 h at 180 °C under atmospheric pressure. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350332
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11659-11666[article] Characterization of solid acid catalysts and their reactivity in the glycolysis of poly(ethylene terephthalate) [texte imprimé] / Minli Zhu, Auteur ; Zengxi Li, Auteur ; Qian Wang, Auteur . - 2012 . - pp. 11659-11666.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11659-11666
Mots-clés : Chemical reactivity Acid catalysis Résumé : Glycolysis of poly(ethylene terephthalate) with ethylene glycol was carried out with the catalysts of sulfated cobalt oxide (SO42―/Co3O4) and zinc-modified sulfated cobalt oxide (SO42―/Co―Zn―O). The catalysts prepared at different calcination temperatures have been characterized by various techniques. These techniques include X-ray diffraction, Raman spectrum, gas adsorption analysis, NH3-temperature programmed desorption, and IR spectroscopy of pyridine adsorption. The performances of these catalysts on the depolymerization of PET under mild conditions were studied, and relationships between the catalysts' textural properties, the surface acidity, and the catalytic activity have been investigated. The experimental results showed that the catalytic activity on glycolysis of PET was significantly improved by the catalysts of binary sulfur oxides of SO42―/Co―Zn―O. The conversion of PET obtained on SO42―/Co―Zn―O-300 °C was 96%, and the selectivity of BHET was 75%, after 3 h at 180 °C under atmospheric pressure. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350332 Exemplaires
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Titre : MnOx – CeO2 / activated carbon honeycomb catalyst for selective catalytic reduction of NO with NH3 at low temperatures Type de document : texte imprimé Auteurs : Yanli Wang, Auteur ; ChuanZhang Ge, Auteur ; Liang Zhan, Auteur Année de publication : 2012 Article en page(s) : pp. 11667–11673 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Catalyst Résumé : Activated carbon honeycomb supported manganese and cerium oxides (MnOx–CeO2/ACH) catalysts were investigated for selective catalytic reduction (SCR) of NO at low temperatures of 80–200 °C. Compared with ACH supported manganese oxide catalyst (MnOx/ACH), MnOx–CeO2/ACH catalysts show much higher SCR activity and higher selectivity to N2. NO conversion can be improved by the addition of CeO2 from less than 50% to 100% at 80–160 °C. The N2 selectivity of higher than 99.8% is obtained over the Ce(1)Mn/ACH catalyst at 80–200 °C. Results indicate that the addition of CeO2 improves the distribution of MnOx and enhances the oxidation of NO to NO2, producing more absorbed NO3– on the catalyst surface, which is then reduced into N2 by NH3. These behaviors account for the promoting effect of CeO2 on the SCR activity. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300555f
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11667–11673[article] MnOx – CeO2 / activated carbon honeycomb catalyst for selective catalytic reduction of NO with NH3 at low temperatures [texte imprimé] / Yanli Wang, Auteur ; ChuanZhang Ge, Auteur ; Liang Zhan, Auteur . - 2012 . - pp. 11667–11673.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11667–11673
Mots-clés : Catalyst Résumé : Activated carbon honeycomb supported manganese and cerium oxides (MnOx–CeO2/ACH) catalysts were investigated for selective catalytic reduction (SCR) of NO at low temperatures of 80–200 °C. Compared with ACH supported manganese oxide catalyst (MnOx/ACH), MnOx–CeO2/ACH catalysts show much higher SCR activity and higher selectivity to N2. NO conversion can be improved by the addition of CeO2 from less than 50% to 100% at 80–160 °C. The N2 selectivity of higher than 99.8% is obtained over the Ce(1)Mn/ACH catalyst at 80–200 °C. Results indicate that the addition of CeO2 improves the distribution of MnOx and enhances the oxidation of NO to NO2, producing more absorbed NO3– on the catalyst surface, which is then reduced into N2 by NH3. These behaviors account for the promoting effect of CeO2 on the SCR activity. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300555f Exemplaires
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Titre : Effect of titania addition on the performance of CoMo / Al2O3 Sour water gas shift catalysts under lean steam to gas ratio conditions Type de document : texte imprimé Auteurs : Bonan Liu, Auteur ; Qiuyun Zong, Auteur ; Peter P. Edwards, Auteur Année de publication : 2012 Article en page(s) : pp. 11674–11680 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Titania Catalysts Résumé :
Effect of Titania Addition on the Performance of CoMo/Al2O3 Sour Water Gas Shift Catalysts under Lean Steam to Gas Ratio Conditions
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Bonan Liu †‡, Qiuyun Zong *‡, Peter P. Edwards †, Fei Zou †, Xian Du †, Zheng Jiang †, Tiancun Xiao *†§, and Hamid AlMegren
† Inorganic Chemistry Laboratory, Oxford University, South Parks RoadOX1, 3QR, U.K.
‡ Qindao Lianxin Chemical, Qingdao, Shandong Province, P R China
§ Guangzhou Boxenergy Technology Ltd, Guangzhou, P R China
Petrochemical Research Institute, King Abdulaziz City for Science and Technology, P.O. Box 6086, Riyadh 11442
Ind. Eng. Chem. Res., 2012, 51 (36), pp 11674–11680
DOI: 10.1021/ie3009764
Publication Date (Web): August 21, 2012
Copyright © 2012 American Chemical Society
*E-mail: xiao.tiancun@chem.ox.ac.uk.
CASSection:
Fossil Fuels, Derivatives, and Related Products
Abstract
CoMo/Al2O3 sour water gas shift catalysts with and without TiO2 modification have been tested in parallel industrial reactors under lean steam/gas conditions for two years, and part of catalyst samples was taken out each year during the maintenance period. The catalyst samples have been characterized using temperature programmed sulfurization (TPS), X-ray diffraction (XRD), and laser Raman and BET surface area measurements. The results have shown that adding TiO2 to the catalyst makes the active components, e.g., Mo and Co, easier to be sulfurized with higher sulfur capacity in the catalyst itself. This may be the main reason why the TiO2 modified CoMo catalyst to be active even at low H2S gas stream. The results from industrial operation showed that adding TiO2 to the shift catalyst increases the catalyst activity and stability, presents the higher shift activity in a broader range of H2S content, depresses the aggregating of the molybdenum oxide, and reduces carbon deposition. In addition, the TiO2 additive in the catalyst also helps to maintain the physical properties of the shift catalysts. In the freshly prepared catalyst, the active components e.g., MoO3 is mainly present in the internal surface or sublayer of the catalyst, but it gradually migrates to the catalyst surface with the time on stream. In summary, the CoMo/Al2O3 based sour water gas shift catalyst showed stable shift performance under the lean steam/gas conditions, adding TiO2 to the catalyst significant improves the catalyst activity and resulting into stable operation in the industrial reactor operation in a wide range of H2S concentrations.ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3009764
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11674–11680[article] Effect of titania addition on the performance of CoMo / Al2O3 Sour water gas shift catalysts under lean steam to gas ratio conditions [texte imprimé] / Bonan Liu, Auteur ; Qiuyun Zong, Auteur ; Peter P. Edwards, Auteur . - 2012 . - pp. 11674–11680.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11674–11680
Mots-clés : Titania Catalysts Résumé :
Effect of Titania Addition on the Performance of CoMo/Al2O3 Sour Water Gas Shift Catalysts under Lean Steam to Gas Ratio Conditions
* Abstract
* HTMLFull Text HTML
* PDFHi-Res PDF[1364 KB]
* PDFPDF w/ Links[480 KB]
* Figures
*
Reference QuickView
Your current credentials do not allow retrieval of the full text.
Purchase the full-text Cart
* PDF/HTML,
figures/images,
references and tables,
(where available)
Bonan Liu †‡, Qiuyun Zong *‡, Peter P. Edwards †, Fei Zou †, Xian Du †, Zheng Jiang †, Tiancun Xiao *†§, and Hamid AlMegren
† Inorganic Chemistry Laboratory, Oxford University, South Parks RoadOX1, 3QR, U.K.
‡ Qindao Lianxin Chemical, Qingdao, Shandong Province, P R China
§ Guangzhou Boxenergy Technology Ltd, Guangzhou, P R China
Petrochemical Research Institute, King Abdulaziz City for Science and Technology, P.O. Box 6086, Riyadh 11442
Ind. Eng. Chem. Res., 2012, 51 (36), pp 11674–11680
DOI: 10.1021/ie3009764
Publication Date (Web): August 21, 2012
Copyright © 2012 American Chemical Society
*E-mail: xiao.tiancun@chem.ox.ac.uk.
CASSection:
Fossil Fuels, Derivatives, and Related Products
Abstract
CoMo/Al2O3 sour water gas shift catalysts with and without TiO2 modification have been tested in parallel industrial reactors under lean steam/gas conditions for two years, and part of catalyst samples was taken out each year during the maintenance period. The catalyst samples have been characterized using temperature programmed sulfurization (TPS), X-ray diffraction (XRD), and laser Raman and BET surface area measurements. The results have shown that adding TiO2 to the catalyst makes the active components, e.g., Mo and Co, easier to be sulfurized with higher sulfur capacity in the catalyst itself. This may be the main reason why the TiO2 modified CoMo catalyst to be active even at low H2S gas stream. The results from industrial operation showed that adding TiO2 to the shift catalyst increases the catalyst activity and stability, presents the higher shift activity in a broader range of H2S content, depresses the aggregating of the molybdenum oxide, and reduces carbon deposition. In addition, the TiO2 additive in the catalyst also helps to maintain the physical properties of the shift catalysts. In the freshly prepared catalyst, the active components e.g., MoO3 is mainly present in the internal surface or sublayer of the catalyst, but it gradually migrates to the catalyst surface with the time on stream. In summary, the CoMo/Al2O3 based sour water gas shift catalyst showed stable shift performance under the lean steam/gas conditions, adding TiO2 to the catalyst significant improves the catalyst activity and resulting into stable operation in the industrial reactor operation in a wide range of H2S concentrations.ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3009764 Exemplaires
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Titre : An approach for the prediction of blistering on polymer – steel lining systems exposed to an aqueous environment Type de document : texte imprimé Auteurs : Chau Van Dinh, Auteur ; M. Kubouchi, Auteur Année de publication : 2012 Article en page(s) : pp. 11681–11687 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Polymeric lining system Résumé : Blistering is a serious problem for a polymeric lining system because is causes delamination, breakage of the lining layer, etc., leading to a reduction/loss of the corrosion protection. The prediction of blistering is a challenging task and is of great significance in practice. In this paper, a model established for the prediction of blistering on a polymer–steel lining system is presented. The model is based on the concept that a blister occurs if its blistering energy exceeds the adhesion energy of the lined polymer. Several lining systems (polyethylene–steel and fluoropolymer–steel) were selected for evaluation of the model. Experimental data showed that the model can be applied to predict the osmotic blistering when a polymeric lining system works under an aqueous environment. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202975s
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11681–11687[article] An approach for the prediction of blistering on polymer – steel lining systems exposed to an aqueous environment [texte imprimé] / Chau Van Dinh, Auteur ; M. Kubouchi, Auteur . - 2012 . - pp. 11681–11687.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11681–11687
Mots-clés : Polymeric lining system Résumé : Blistering is a serious problem for a polymeric lining system because is causes delamination, breakage of the lining layer, etc., leading to a reduction/loss of the corrosion protection. The prediction of blistering is a challenging task and is of great significance in practice. In this paper, a model established for the prediction of blistering on a polymer–steel lining system is presented. The model is based on the concept that a blister occurs if its blistering energy exceeds the adhesion energy of the lined polymer. Several lining systems (polyethylene–steel and fluoropolymer–steel) were selected for evaluation of the model. Experimental data showed that the model can be applied to predict the osmotic blistering when a polymeric lining system works under an aqueous environment. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202975s Exemplaires
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Titre : Heteroflocculation of a cationic oil - in - water emulsion resulting from fontainebleau’s sandstone powder addition as a model for asphalt emulsion breakup Type de document : texte imprimé Auteurs : Ronald A. Mercado, Auteur ; Veronique Sadtler, Auteur ; Philippe Marchal, Auteur Année de publication : 2012 Article en page(s) : pp. 11688-11694 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Modeling Powder Emulsion Résumé : The use of asphalt emulsions for road fabrication is rapidly gaining in importance mainly due to energy savings, less environmental impact, and better properties of the final product. However, the formulation of these emulsions still requires a better understanding, particularly concerning their breaking phenomena. When a cationic model emulsion is contacted with a solid having a negative-charged surface, physicochemical driving forces result in the emulsion destabilization. As a consequence, a viscosity reduction of the remaining emulsion is observed, as well as the emulsion breakup through a heteroflocculation mechanism provided the solid surface is large enough. Emulsion systems at equilibrium, containing cetylpyridinium chloride (CPC), paraffin oil, and Fontainebleau's sandstone powder and having different droplet sizes, are studied. The results show that the dispersed oil fraction decreases after each addition of sandstone aliquots, and this depends on the concentration of CPC in the continuous phase of the emulsion. As the droplet size and distribution remain constant during the process, it is assumed that the emulsion heteroflocculation is the result of direct oil droplets adhesion on the sand surface, followed by their coalescence around the sand particles. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350336
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11688-11694[article] Heteroflocculation of a cationic oil - in - water emulsion resulting from fontainebleau’s sandstone powder addition as a model for asphalt emulsion breakup [texte imprimé] / Ronald A. Mercado, Auteur ; Veronique Sadtler, Auteur ; Philippe Marchal, Auteur . - 2012 . - pp. 11688-11694.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11688-11694
Mots-clés : Modeling Powder Emulsion Résumé : The use of asphalt emulsions for road fabrication is rapidly gaining in importance mainly due to energy savings, less environmental impact, and better properties of the final product. However, the formulation of these emulsions still requires a better understanding, particularly concerning their breaking phenomena. When a cationic model emulsion is contacted with a solid having a negative-charged surface, physicochemical driving forces result in the emulsion destabilization. As a consequence, a viscosity reduction of the remaining emulsion is observed, as well as the emulsion breakup through a heteroflocculation mechanism provided the solid surface is large enough. Emulsion systems at equilibrium, containing cetylpyridinium chloride (CPC), paraffin oil, and Fontainebleau's sandstone powder and having different droplet sizes, are studied. The results show that the dispersed oil fraction decreases after each addition of sandstone aliquots, and this depends on the concentration of CPC in the continuous phase of the emulsion. As the droplet size and distribution remain constant during the process, it is assumed that the emulsion heteroflocculation is the result of direct oil droplets adhesion on the sand surface, followed by their coalescence around the sand particles. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350336 Exemplaires
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Titre : Orientation structures in injection - molded pellets of polystyrene / carbon nanotube nanocomposites Type de document : texte imprimé Auteurs : Cuiping Yuan, Auteur ; Guangming Chen, Auteur ; Jiping Yang, Auteur Année de publication : 2012 Article en page(s) : pp. 11695-11699 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Nanocomposite Pellet Résumé : The orientation structures of both carbon nanotubes (CNTs) and polymer molecular chains in the skin―core structure of polystyrene/multiwalled carbon nanotube (PS/MWCNT) nanocomposite melt-injection-molded pellets were examined. Scanning electron microscopic (SEM) and transmission electron microscopic (TEM) images clearly show the MWCNT preferred orientation along the melt shearing direction, while polarized Raman spectroscopy results consolidate the MWCNT preferred orientation in each of the skin, medium, and core layers of the injection-molded pellets. By infrared dichroism measurements, a preferred orientation of the PS side groups (phenyl rings) perpendicular to the melt shearing direction was deduced at all depths of the present injection-molded nanocomposite pellet. Meanwhile, the MWCNTs have little effect on the random orientation of the PS main chain (-CH2- groups) with a dichrolc ratio near unity. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350337
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11695-11699[article] Orientation structures in injection - molded pellets of polystyrene / carbon nanotube nanocomposites [texte imprimé] / Cuiping Yuan, Auteur ; Guangming Chen, Auteur ; Jiping Yang, Auteur . - 2012 . - pp. 11695-11699.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11695-11699
Mots-clés : Nanocomposite Pellet Résumé : The orientation structures of both carbon nanotubes (CNTs) and polymer molecular chains in the skin―core structure of polystyrene/multiwalled carbon nanotube (PS/MWCNT) nanocomposite melt-injection-molded pellets were examined. Scanning electron microscopic (SEM) and transmission electron microscopic (TEM) images clearly show the MWCNT preferred orientation along the melt shearing direction, while polarized Raman spectroscopy results consolidate the MWCNT preferred orientation in each of the skin, medium, and core layers of the injection-molded pellets. By infrared dichroism measurements, a preferred orientation of the PS side groups (phenyl rings) perpendicular to the melt shearing direction was deduced at all depths of the present injection-molded nanocomposite pellet. Meanwhile, the MWCNTs have little effect on the random orientation of the PS main chain (-CH2- groups) with a dichrolc ratio near unity. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350337 Exemplaires
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Titre : Copper Ferrite-Graphene Hybrid : A Multifunctional Heteroarchitecture for Photocatalysis and Energy Storage Type de document : texte imprimé Auteurs : Yongsheng Fu, Auteur ; Qun Chen, Auteur ; Mingyang He, Auteur Année de publication : 2012 Article en page(s) : pp. 11700-11709 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Storage Photocatalysis Résumé : A straightforward strategy is designed for the fabrication of CuFe2O4-graphene heteroarchitecture via a one-step hydrothermal route to allow multifunctional properties, i.e., magnetic cycling, high photocatalytic activity under visible light irradiation, and excellent electrochemical behaviors for use as the anode in lithium-ion batteries (LIBs). Transmission electron microscopy (TEM) observations indicate that graphene sheets are exfoliated and decorated with hexagonal CuFe2O4 nanoflakes. The photocatalytic activity measurements demonstrate that the combination of CuFe2O4 and graphene results in a dramatic conversion of the inert CuFe2O4 into a highly active catalyst for the degradation of methylene blue (MB) under visible light irradiation. CuFe2O4 nanoparticles themselves have excellent magnetic properties, which makes the CuFe2O4-graphene heteroarchitecture magnetically recyclable in a suspension system. It should be pointed out that the CuFe2O4-graphene (with 25 wt % graphene) heteroarchitecture as anode material for LIBs shows a high specific reversible capacity up to 1165 mAh g-1 with good cycling stability and rate capability. The superior photocatalytic activity and electrochemical performance of the CuFe2O4-graphene nanocomposite can be attributed to its unique heteroarchitechture, which provides the remarkable synergistic effect between the CuFe2O4 nanoflakes and the graphene sheets. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350338
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11700-11709[article] Copper Ferrite-Graphene Hybrid : A Multifunctional Heteroarchitecture for Photocatalysis and Energy Storage [texte imprimé] / Yongsheng Fu, Auteur ; Qun Chen, Auteur ; Mingyang He, Auteur . - 2012 . - pp. 11700-11709.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11700-11709
Mots-clés : Storage Photocatalysis Résumé : A straightforward strategy is designed for the fabrication of CuFe2O4-graphene heteroarchitecture via a one-step hydrothermal route to allow multifunctional properties, i.e., magnetic cycling, high photocatalytic activity under visible light irradiation, and excellent electrochemical behaviors for use as the anode in lithium-ion batteries (LIBs). Transmission electron microscopy (TEM) observations indicate that graphene sheets are exfoliated and decorated with hexagonal CuFe2O4 nanoflakes. The photocatalytic activity measurements demonstrate that the combination of CuFe2O4 and graphene results in a dramatic conversion of the inert CuFe2O4 into a highly active catalyst for the degradation of methylene blue (MB) under visible light irradiation. CuFe2O4 nanoparticles themselves have excellent magnetic properties, which makes the CuFe2O4-graphene heteroarchitecture magnetically recyclable in a suspension system. It should be pointed out that the CuFe2O4-graphene (with 25 wt % graphene) heteroarchitecture as anode material for LIBs shows a high specific reversible capacity up to 1165 mAh g-1 with good cycling stability and rate capability. The superior photocatalytic activity and electrochemical performance of the CuFe2O4-graphene nanocomposite can be attributed to its unique heteroarchitechture, which provides the remarkable synergistic effect between the CuFe2O4 nanoflakes and the graphene sheets. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350338 Exemplaires
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Titre : Synthesis of optically active ZnS – carbon nanotube nanocomposites in supercritical carbon dioxide via a single source diethyldithiocarbamate precursor Type de document : texte imprimé Auteurs : Michael J. Casciato, Auteur ; Galit Levitin, Auteur ; Dennis W. Hess, Auteur Année de publication : 2012 Article en page(s) : pp. 11710-11716 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Precursor Supercritical state Carbon dioxide Nanocomposite Résumé : Zinc sulfide nanoparticles (ZnS NPs) have been deposited on carbon nanotubes (CNTs) from a single source precursor, zinc(II) bis(diethyldithiocarbamate), using a one-step batch supercritical carbon dioxide (sc-CO2) process. By eliminating the need for an additional sulfur source while simultaneously employing CO2 as the solvent, this method replaces environmentally unfriendly chemicals commonly used in ZnS―CNT nanocomposite synthesis such as ethylene glycol, thiourea, and hydrogen sulfide. ZnS NP morphology displayed large clusters (209 ± 24 nm) that were comprised of smaller particles (16.9 ± 1.9 nm). Photoluminescence spectroscopy demonstrated broad band fluorescence of the ZnS―CNT nanocomposite at 440 nm (2.82 eV) and fluorescence of a Mn doped ZnS-CNT nanocomposite at 445 nm (2.79 eV) and 602 nm (2.07 eV), also in agreement with previous studies. The ZnS―CNT nanocomposite was compared to ZnS NPs synthesized in the absence of a substrate; results indicated that the ZnS―CNT nanocomposite was formed by a heterogeneous reaction mechanism in the sc-CO2 system. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350339
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11710-11716[article] Synthesis of optically active ZnS – carbon nanotube nanocomposites in supercritical carbon dioxide via a single source diethyldithiocarbamate precursor [texte imprimé] / Michael J. Casciato, Auteur ; Galit Levitin, Auteur ; Dennis W. Hess, Auteur . - 2012 . - pp. 11710-11716.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11710-11716
Mots-clés : Precursor Supercritical state Carbon dioxide Nanocomposite Résumé : Zinc sulfide nanoparticles (ZnS NPs) have been deposited on carbon nanotubes (CNTs) from a single source precursor, zinc(II) bis(diethyldithiocarbamate), using a one-step batch supercritical carbon dioxide (sc-CO2) process. By eliminating the need for an additional sulfur source while simultaneously employing CO2 as the solvent, this method replaces environmentally unfriendly chemicals commonly used in ZnS―CNT nanocomposite synthesis such as ethylene glycol, thiourea, and hydrogen sulfide. ZnS NP morphology displayed large clusters (209 ± 24 nm) that were comprised of smaller particles (16.9 ± 1.9 nm). Photoluminescence spectroscopy demonstrated broad band fluorescence of the ZnS―CNT nanocomposite at 440 nm (2.82 eV) and fluorescence of a Mn doped ZnS-CNT nanocomposite at 445 nm (2.79 eV) and 602 nm (2.07 eV), also in agreement with previous studies. The ZnS―CNT nanocomposite was compared to ZnS NPs synthesized in the absence of a substrate; results indicated that the ZnS―CNT nanocomposite was formed by a heterogeneous reaction mechanism in the sc-CO2 system. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350339 Exemplaires
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Titre : Simplified methodology for the design and optimization of thermally coupled reactive distillation systems Type de document : texte imprimé Auteurs : Fernando Israel Gómez-Castro, Auteur ; Vicente Rico-Ramirez, Auteur ; Juan Gabriel Segovia-Hernandez, Auteur Année de publication : 2012 Article en page(s) : pp. 11717-11730 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Distillation with reaction Optimization Design Résumé : New intensified schemes have been recently proposed as an attempt to reduce energy requirements and equipment costs in reaction-separation processes. A design methodology for thermally coupled reactive distillation systems is proposed in this work. To design the columns, a method based on the Fenske―Underwood―Gilliland (FUG) equations is proposed and tested. The FUG equations, the mass and energy balances, and the phase equilibrium equations are used to formulate the model of the intensified systems. Such a model is then solved as a nonlinear programming problem; the objective function is the minimization of the heat duty in the column. Biodiesel production through the esterification of oleic acid with supercritical methanol is used as a case study. Results show the feasibility of obtaining designs with low energy requirements by using the proposed methodology. Because of nonconvexities present in the formulation, the estimated interlinking flows for the reactive Petlyuk column might not correspond to a minimum for energy requirements. Nevertheless, the resulting designs not only show low heat duties, with a difference of less than 2% from that minimum, but also have the capacity of achieving the desired conversion and purities. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350340
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11717-11730[article] Simplified methodology for the design and optimization of thermally coupled reactive distillation systems [texte imprimé] / Fernando Israel Gómez-Castro, Auteur ; Vicente Rico-Ramirez, Auteur ; Juan Gabriel Segovia-Hernandez, Auteur . - 2012 . - pp. 11717-11730.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11717-11730
Mots-clés : Distillation with reaction Optimization Design Résumé : New intensified schemes have been recently proposed as an attempt to reduce energy requirements and equipment costs in reaction-separation processes. A design methodology for thermally coupled reactive distillation systems is proposed in this work. To design the columns, a method based on the Fenske―Underwood―Gilliland (FUG) equations is proposed and tested. The FUG equations, the mass and energy balances, and the phase equilibrium equations are used to formulate the model of the intensified systems. Such a model is then solved as a nonlinear programming problem; the objective function is the minimization of the heat duty in the column. Biodiesel production through the esterification of oleic acid with supercritical methanol is used as a case study. Results show the feasibility of obtaining designs with low energy requirements by using the proposed methodology. Because of nonconvexities present in the formulation, the estimated interlinking flows for the reactive Petlyuk column might not correspond to a minimum for energy requirements. Nevertheless, the resulting designs not only show low heat duties, with a difference of less than 2% from that minimum, but also have the capacity of achieving the desired conversion and purities. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350340 Exemplaires
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Titre : Economic plantwide control of a C4 isomerization process Type de document : texte imprimé Auteurs : Rahul Jagtap, Auteur ; Nitin Kaistha, Auteur Année de publication : 2012 Article en page(s) : pp. 11731–11743 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Isomerization process Résumé : Plantwide control system design for economically optimal operation over a large throughput range of a C4 isomerization process is considered. The steady-state process degrees of freedom (dofs; eight in total) are optimized for a given throughput (mode I) and maximum throughput (mode II). At maximum throughput, all of the steady-state dofs are exhausted in driving as many constraints (inequality/equality) active. For this process, it is possible to synthesize a simple decentralized plantwide control system (CS1) for tight control of all of the active constraints at maximum throughput with negligible back-off due to transients with satisfactory inventory regulation and process stabilization. A unique feature of CS1 is the location of the throughput manipulator (TPM) inside the plant (in contrast to that at the process feed) and its relocation due to input saturation in a split range arrangement. A comparison with the conventional structure (CS2) with TPM at the process feed and conventional overrides for handling constraints demonstrates the economic and dynamic superiority of CS1. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3001293
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11731–11743[article] Economic plantwide control of a C4 isomerization process [texte imprimé] / Rahul Jagtap, Auteur ; Nitin Kaistha, Auteur . - 2012 . - pp. 11731–11743.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11731–11743
Mots-clés : Isomerization process Résumé : Plantwide control system design for economically optimal operation over a large throughput range of a C4 isomerization process is considered. The steady-state process degrees of freedom (dofs; eight in total) are optimized for a given throughput (mode I) and maximum throughput (mode II). At maximum throughput, all of the steady-state dofs are exhausted in driving as many constraints (inequality/equality) active. For this process, it is possible to synthesize a simple decentralized plantwide control system (CS1) for tight control of all of the active constraints at maximum throughput with negligible back-off due to transients with satisfactory inventory regulation and process stabilization. A unique feature of CS1 is the location of the throughput manipulator (TPM) inside the plant (in contrast to that at the process feed) and its relocation due to input saturation in a split range arrangement. A comparison with the conventional structure (CS2) with TPM at the process feed and conventional overrides for handling constraints demonstrates the economic and dynamic superiority of CS1. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3001293 Exemplaires
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Titre : Assessment of Proportional–Integral Control Loop Performance for Input Load Disturbance Rejection Type de document : texte imprimé Auteurs : Zhenpeng Yu, Auteur ; Jiandong Wang, Auteur Année de publication : 2012 Article en page(s) : pp. 11744–11752 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Disturbance rejection Integral proportional control Résumé : This paper studies the performance assessment of proportional–integral (PI) control loops in terms of rejecting input load disturbances. The direct synthesis (DS-d) method for disturbance rejection is adopted to design PI controller parameters. The lower bound of the integrated absolute error (IAE) is established, from closed-loop responses subject to step or other general types of input load disturbance changes. A DS-d IAE-based index is formulated by using the lower bound of the IAE as a performance benchmark. A novel seminonparametric method is proposed to estimate the required parameters for calculating the performance index. Simulation and experimental examples are provided to validate the performance benchmark and to demonstrate the effectiveness of the proposed performance index. REFERENCE : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350342
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11744–11752[article] Assessment of Proportional–Integral Control Loop Performance for Input Load Disturbance Rejection [texte imprimé] / Zhenpeng Yu, Auteur ; Jiandong Wang, Auteur . - 2012 . - pp. 11744–11752.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11744–11752
Mots-clés : Disturbance rejection Integral proportional control Résumé : This paper studies the performance assessment of proportional–integral (PI) control loops in terms of rejecting input load disturbances. The direct synthesis (DS-d) method for disturbance rejection is adopted to design PI controller parameters. The lower bound of the integrated absolute error (IAE) is established, from closed-loop responses subject to step or other general types of input load disturbance changes. A DS-d IAE-based index is formulated by using the lower bound of the IAE as a performance benchmark. A novel seminonparametric method is proposed to estimate the required parameters for calculating the performance index. Simulation and experimental examples are provided to validate the performance benchmark and to demonstrate the effectiveness of the proposed performance index. REFERENCE : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350342 Exemplaires
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Titre : Design and control of thermally coupled reactive distillation for the production of isopropyl acetate Type de document : texte imprimé Auteurs : Hao-Yeh Lee, Auteur ; I-Kuan Lai, Auteur ; Hsiao-Ping Huang, Auteur Année de publication : 2012 Article en page(s) : pp. 11753–11763 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Isopropyl Thermally coupled Résumé : Isopropyl acetates are important organic solvents that are widely used in the production of varnishes, ink, synthetic resins, and adhesive agents. Previous studies developed a process for the production of isopropyl acetate incorporating a reactive distillation (RD) column, a decanter, and a stripper. According to the previous study, the rectifying section of the RD column has a prominent remixing phenomenon. Furthermore, the overhead compositions of RD column and the stripper are all within the liquid–liquid equilibrium envelope. Based on the above observations, a thermally coupled design of this process is established. The key points in the thermally coupled design are: to move the location of the decanter to the stripper side, to totally reflux the organic phase outlet stream, and to sidedraw a liquid stream from the stripper to the RD column. Simulation result shows that 23.14% energy savings can be realized using the proposed thermally coupled design. The control strategy of the proposed design flowsheet is also investigated using tray temperature control loops to indirectly control the product composition. The proposed control strategy is capable of maintaining high-purity product, despite changes in feed composition and throughput. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300647h
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11753–11763[article] Design and control of thermally coupled reactive distillation for the production of isopropyl acetate [texte imprimé] / Hao-Yeh Lee, Auteur ; I-Kuan Lai, Auteur ; Hsiao-Ping Huang, Auteur . - 2012 . - pp. 11753–11763.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11753–11763
Mots-clés : Isopropyl Thermally coupled Résumé : Isopropyl acetates are important organic solvents that are widely used in the production of varnishes, ink, synthetic resins, and adhesive agents. Previous studies developed a process for the production of isopropyl acetate incorporating a reactive distillation (RD) column, a decanter, and a stripper. According to the previous study, the rectifying section of the RD column has a prominent remixing phenomenon. Furthermore, the overhead compositions of RD column and the stripper are all within the liquid–liquid equilibrium envelope. Based on the above observations, a thermally coupled design of this process is established. The key points in the thermally coupled design are: to move the location of the decanter to the stripper side, to totally reflux the organic phase outlet stream, and to sidedraw a liquid stream from the stripper to the RD column. Simulation result shows that 23.14% energy savings can be realized using the proposed thermally coupled design. The control strategy of the proposed design flowsheet is also investigated using tray temperature control loops to indirectly control the product composition. The proposed control strategy is capable of maintaining high-purity product, despite changes in feed composition and throughput. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300647h Exemplaires
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Titre : Optimization of reverse osmosis networks with spiral - wound modules Type de document : texte imprimé Auteurs : Yawei Du, Auteur ; Lixin Xie, Auteur ; Yuxin Wang, Auteur Année de publication : 2012 Article en page(s) : pp. 11764-11777 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Spiral Membrane separation Reverse osmosis Optimization Résumé : An optimization of reverse osmosis (RO) networks for seawater desalination with spiral-wound modules (SWM) was presented in this work. The membrane transport model, which was based on the mass and momentum transport equations, took into consideration the longitudinal variation of the velocity, the pressure, and the salt concentration in the membrane modules. The pressure exchanger (PX) was included in the RO superstructure, and salinity increase caused by volumetric mixing in the PX was considered. The results obtained from the presented model were compared with the actual plant operational data from literature and found to be in good agreement with relative errors of 0.81%∼2.15% and 0.01%∼0.09%, in terms of water recovery and salt rejection, respectively. The optimum design problem was formulated as a mixed integer nonlinear programming (MINLP) problem. The variation of feed salinity was studied using the RO networks model. For the feed concentration higher than 32 kg/m3, one-stage RO system is favored. When the feed concentration is below 28 kg/m3, two-stage RO system is the better choice. The unit product cost increases with the decreases of permeate concentration requirement. For the looser permeate concentration requirement (0.30 kg/m3), one-pass configuration can meet the required quality of desalted water. When the lower permeate quality requirement of concentration is from 0.050―0.20 kg/m3, a two-pass system is more suitable. The influence of system recovery rate on the plant performance was discussed. Finally, sensitivity analysis showed that the total annualized cost is highly sensitive to the feed flow rate, the operating pressure, and electricity cost, while the energy consumption is highly sensitive to the operating pressure, the feed salinity, and the feed temperature. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350344
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11764-11777[article] Optimization of reverse osmosis networks with spiral - wound modules [texte imprimé] / Yawei Du, Auteur ; Lixin Xie, Auteur ; Yuxin Wang, Auteur . - 2012 . - pp. 11764-11777.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11764-11777
Mots-clés : Spiral Membrane separation Reverse osmosis Optimization Résumé : An optimization of reverse osmosis (RO) networks for seawater desalination with spiral-wound modules (SWM) was presented in this work. The membrane transport model, which was based on the mass and momentum transport equations, took into consideration the longitudinal variation of the velocity, the pressure, and the salt concentration in the membrane modules. The pressure exchanger (PX) was included in the RO superstructure, and salinity increase caused by volumetric mixing in the PX was considered. The results obtained from the presented model were compared with the actual plant operational data from literature and found to be in good agreement with relative errors of 0.81%∼2.15% and 0.01%∼0.09%, in terms of water recovery and salt rejection, respectively. The optimum design problem was formulated as a mixed integer nonlinear programming (MINLP) problem. The variation of feed salinity was studied using the RO networks model. For the feed concentration higher than 32 kg/m3, one-stage RO system is favored. When the feed concentration is below 28 kg/m3, two-stage RO system is the better choice. The unit product cost increases with the decreases of permeate concentration requirement. For the looser permeate concentration requirement (0.30 kg/m3), one-pass configuration can meet the required quality of desalted water. When the lower permeate quality requirement of concentration is from 0.050―0.20 kg/m3, a two-pass system is more suitable. The influence of system recovery rate on the plant performance was discussed. Finally, sensitivity analysis showed that the total annualized cost is highly sensitive to the feed flow rate, the operating pressure, and electricity cost, while the energy consumption is highly sensitive to the operating pressure, the feed salinity, and the feed temperature. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350344 Exemplaires
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Titre : Performance of an IGCC plant with carbon capture and coal - CO2 - slurry feed : Impact of coal rank, slurry loading, and syngas cooling technology Type de document : texte imprimé Auteurs : Cristina Botero, Auteur ; Randall P. Field, Auteur ; Robert D. Brasington, Auteur Année de publication : 2012 Article en page(s) : pp. 11778-11790 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Cooling Synthesis gas Loading Carbon dioxide Coal Résumé : The high heat capacity and latent enthalpy of vaporization of water lead to a low gasification efficiency in gasifiers fed with coal-water slurry. Liquid carbon dioxide, CO2(1), has been suggested as an alternative slurrying medium to improve the efficiency of low-rank coal gasification in integrated gasification combined cycle power plants with carbon capture. Steady-state process simulation is used in this work to confirm published findings and present a comprehensive assessment of the impact of the coal rank, gasifier cooling technology, and CO2 slurry loading uncertainty on the performance advantage of CO2 slurry-fed plants. A power generation efficiency improvement of up to 25% (5%-points) is predicted, which is shown to increase with decreasing coal rank and to be highest for full-quench gasifier cooling technology; the latter is a significant source of capital cost savings and is especially attractive when combined with CO2 slurry feed. Using CO2(1) instead of water slurry reduces the performance penalty of low-rank coal gasification by half, thus substantially improving the feedstock flexibility of the plant. With a single exception, the performance benefit of coal-CO2 slurry was found to be outside the uncertainty range of the slurry loading, which is still one of the key unknowns of this alternative feed system. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350345
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11778-11790[article] Performance of an IGCC plant with carbon capture and coal - CO2 - slurry feed : Impact of coal rank, slurry loading, and syngas cooling technology [texte imprimé] / Cristina Botero, Auteur ; Randall P. Field, Auteur ; Robert D. Brasington, Auteur . - 2012 . - pp. 11778-11790.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11778-11790
Mots-clés : Cooling Synthesis gas Loading Carbon dioxide Coal Résumé : The high heat capacity and latent enthalpy of vaporization of water lead to a low gasification efficiency in gasifiers fed with coal-water slurry. Liquid carbon dioxide, CO2(1), has been suggested as an alternative slurrying medium to improve the efficiency of low-rank coal gasification in integrated gasification combined cycle power plants with carbon capture. Steady-state process simulation is used in this work to confirm published findings and present a comprehensive assessment of the impact of the coal rank, gasifier cooling technology, and CO2 slurry loading uncertainty on the performance advantage of CO2 slurry-fed plants. A power generation efficiency improvement of up to 25% (5%-points) is predicted, which is shown to increase with decreasing coal rank and to be highest for full-quench gasifier cooling technology; the latter is a significant source of capital cost savings and is especially attractive when combined with CO2 slurry feed. Using CO2(1) instead of water slurry reduces the performance penalty of low-rank coal gasification by half, thus substantially improving the feedstock flexibility of the plant. With a single exception, the performance benefit of coal-CO2 slurry was found to be outside the uncertainty range of the slurry loading, which is still one of the key unknowns of this alternative feed system. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350345 Exemplaires
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Titre : Unveiling the mechanism of in situ crystallization in the spray drying of sugars Type de document : texte imprimé Auteurs : M. W. Woo, Auteur ; N. Fu, Auteur ; F. T. Moo, Auteur Année de publication : 2012 Article en page(s) : pp. 11791-11802 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Spray drying Crystallization In situ Résumé : This work explored the significance of the drying history dependent effect on in situ crystallization in spray drying. Analysis was based on actual single droplet drying kinetics at different drying air temperatures. This paper reports the changes in droplet Tg, T ― Tg, solubility, and supersaturation based on actual experimental data as drying progressed. The glass transition analysis suggests that a critical crystallization period might be significant for in situ crystallization in spray drying. This finding highlights the danger in using the final particle condition, delineated by the dyer outlet conditions, as a measure of partial crystallization in spray dried particles. Extended analysis using the nucleation-growth mechanism pointed to the same crystallization phenomenon analogous to the critical crystallization period concept. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350346
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11791-11802[article] Unveiling the mechanism of in situ crystallization in the spray drying of sugars [texte imprimé] / M. W. Woo, Auteur ; N. Fu, Auteur ; F. T. Moo, Auteur . - 2012 . - pp. 11791-11802.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11791-11802
Mots-clés : Spray drying Crystallization In situ Résumé : This work explored the significance of the drying history dependent effect on in situ crystallization in spray drying. Analysis was based on actual single droplet drying kinetics at different drying air temperatures. This paper reports the changes in droplet Tg, T ― Tg, solubility, and supersaturation based on actual experimental data as drying progressed. The glass transition analysis suggests that a critical crystallization period might be significant for in situ crystallization in spray drying. This finding highlights the danger in using the final particle condition, delineated by the dyer outlet conditions, as a measure of partial crystallization in spray dried particles. Extended analysis using the nucleation-growth mechanism pointed to the same crystallization phenomenon analogous to the critical crystallization period concept. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350346 Exemplaires
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Titre : Use of supercritical CO2 and N2 as dissolved gases for the atomization of ethanol and water Type de document : texte imprimé Auteurs : Giuseppe Caputo, Auteur ; Sara Liparoti, Auteur ; Renata Adami, Auteur Année de publication : 2012 Article en page(s) : pp. 11803-11808 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Supercritical state Carbon dioxide Résumé : Supercritical dissolved gas atomization (SDGA) is an atomization process in which a gas at temperatures and pressures above the critical point is used as the atomizing medium. The concept of SDGA has been applied mainly using CO2 as atomizing gas in various processes developed for the production of fine particles of pharmaceuticals, polymers, and chemical products and for the atomization of fuels. In this work, SDGA, using ethanol and water as the liquids to be atomized, has been experimentally studied. The spray characteristics, in terms of droplet size and distribution, have been investigated using a laser diffraction analyzer. Ethanol has been chosen due to the large miscibility with CO2 and for its wide use as a solvent in particle formation processes. The use of N2 as an atomizing gas has been also studied. Very narrow droplet size distributions were produced down to 2.5 μm. The properties of the liquid to be atomized (water or ethanol) showed a negligible effect on droplet size. The main parameter that influences droplet size is the gas to liquid mass ratio. Nitrogen has a better potentiality as an atomizing gas with respect to carbon dioxide. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350347
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11803-11808[article] Use of supercritical CO2 and N2 as dissolved gases for the atomization of ethanol and water [texte imprimé] / Giuseppe Caputo, Auteur ; Sara Liparoti, Auteur ; Renata Adami, Auteur . - 2012 . - pp. 11803-11808.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11803-11808
Mots-clés : Supercritical state Carbon dioxide Résumé : Supercritical dissolved gas atomization (SDGA) is an atomization process in which a gas at temperatures and pressures above the critical point is used as the atomizing medium. The concept of SDGA has been applied mainly using CO2 as atomizing gas in various processes developed for the production of fine particles of pharmaceuticals, polymers, and chemical products and for the atomization of fuels. In this work, SDGA, using ethanol and water as the liquids to be atomized, has been experimentally studied. The spray characteristics, in terms of droplet size and distribution, have been investigated using a laser diffraction analyzer. Ethanol has been chosen due to the large miscibility with CO2 and for its wide use as a solvent in particle formation processes. The use of N2 as an atomizing gas has been also studied. Very narrow droplet size distributions were produced down to 2.5 μm. The properties of the liquid to be atomized (water or ethanol) showed a negligible effect on droplet size. The main parameter that influences droplet size is the gas to liquid mass ratio. Nitrogen has a better potentiality as an atomizing gas with respect to carbon dioxide. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350347 Exemplaires
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Titre : Comparison of the a priori COSMO - RS models and group contribution methods : Original UNIFAC, modified UNIFAC(Do), and modified UNIFAC(Do) Co/nsortium Type de document : texte imprimé Auteurs : Zhimin Xue, Auteur ; Tiancheng Mu, Auteur ; Jürgen Gmehling, Auteur Année de publication : 2012 Article en page(s) : pp. 11809-11817 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Group contribution method Modeling Résumé : A comparison of the performances of the COSMO-SAC, COSMO-RS(Ol), original UNIFAC, modified UNIFAC(Do), and modified UNIFAC(Do) Consortium for activity coefficients at infinite dilution and binary VLE data is presented. The σ-profiles used in performing COSMO-SAC and COSMO-RS(Ol) calculations were taken from the published σ-profile database VT 2005. The predicted results were compared with the experimental data stored in the Dortmund Data Bank and analyzed with respect to the types of components in the mixture. The results show that the UNIFAC models based on experimental data are superior to the a priori COSMO-RS models. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350348
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11809-11817[article] Comparison of the a priori COSMO - RS models and group contribution methods : Original UNIFAC, modified UNIFAC(Do), and modified UNIFAC(Do) Co/nsortium [texte imprimé] / Zhimin Xue, Auteur ; Tiancheng Mu, Auteur ; Jürgen Gmehling, Auteur . - 2012 . - pp. 11809-11817.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11809-11817
Mots-clés : Group contribution method Modeling Résumé : A comparison of the performances of the COSMO-SAC, COSMO-RS(Ol), original UNIFAC, modified UNIFAC(Do), and modified UNIFAC(Do) Consortium for activity coefficients at infinite dilution and binary VLE data is presented. The σ-profiles used in performing COSMO-SAC and COSMO-RS(Ol) calculations were taken from the published σ-profile database VT 2005. The predicted results were compared with the experimental data stored in the Dortmund Data Bank and analyzed with respect to the types of components in the mixture. The results show that the UNIFAC models based on experimental data are superior to the a priori COSMO-RS models. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350348 Exemplaires
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