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Vol. 47 n°14 - Juillet 2008 [texte imprimé] . - 2008 . - p. 4561-4970 : ill. ; 28 cm. Chemical engineering Langues : Anglais (eng)
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Ajouter le résultat dans votre panierHeterogeneous catalytic hydrogenation in supercritical fluids / Tsunetake Seki in Industrial & engineering chemistry research, Vol. 47 n°14 (Juillet 2008)
inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4561–4585
Titre : Heterogeneous catalytic hydrogenation in supercritical fluids : potential and limitations Type de document : texte imprimé Auteurs : Tsunetake Seki, Auteur ; Jan-Dierk Grunwaldt, Auteur ; Alfons Baiker, Auteur Année de publication : 2008 Article en page(s) : p. 4561–4585 Note générale : Bibliogr. p. 4583-4585 Langues : Anglais (eng) Mots-clés : Supercritical fluids Organic compounds Heterogeneous catalytic hydrogenation Résumé : Heterogeneous catalytic hydrogenation of organic compounds in supercritical fluids (SCFs) is reviewed, covering the work published up to 2007. The potential as well as limitations of the application of SCFs as solvents are examined based on the existing knowledge. SCFs, particularly CO2, offer some attractive opportunities as substitutes of classical organic solvents, but their beneficial application requires careful weighing of economical and ecological factors. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071649g [article] Heterogeneous catalytic hydrogenation in supercritical fluids : potential and limitations [texte imprimé] / Tsunetake Seki, Auteur ; Jan-Dierk Grunwaldt, Auteur ; Alfons Baiker, Auteur . - 2008 . - p. 4561–4585.
Bibliogr. p. 4583-4585
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4561–4585
Mots-clés : Supercritical fluids Organic compounds Heterogeneous catalytic hydrogenation Résumé : Heterogeneous catalytic hydrogenation of organic compounds in supercritical fluids (SCFs) is reviewed, covering the work published up to 2007. The potential as well as limitations of the application of SCFs as solvents are examined based on the existing knowledge. SCFs, particularly CO2, offer some attractive opportunities as substitutes of classical organic solvents, but their beneficial application requires careful weighing of economical and ecological factors. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071649g Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4586–4597
Titre : Functionalized membranes by layer-by-layer assembly of polyelectrolytes and in situ polymerization of acrylic acid for applications in enzymatic catalysis Type de document : texte imprimé Auteurs : Saurav Datta, Auteur ; Caitlyn Cecil, Auteur ; Bhattacharyya, D., Auteur Année de publication : 2008 Article en page(s) : p. 4586–4597 Note générale : Bibliogr. p. 4595-4597 Langues : Anglais (eng) Mots-clés : Functionalized polymeric membrane Enzymatic catalysis Layer-by-layer assembly technique Résumé : This research work was directed toward the development of highly active, stable, and reusable functionalized polymeric membrane domains for enzymatic catalysis. Functionalized membranes were created by two different approaches. In the first approach, which involved alternative attachment of cationic and anionic polyelectrolytes, functionalization was performed using a layer-by-layer (LBL) assembly technique within a nylon-based microfiltration (MF) membrane. In the second approach, a hydrophobic polyvinylidene fluoride (PVDF) MF membrane was functionalized by the in situ polymerization of acrylic acid. The enzyme, glucose oxidase (GOX), was then electrostatically immobilized inside the functionalized membrane domains to study the catalytic oxidation of glucose to gluconic acid and H2O2. Characterization of the functionalized membranes, in terms of polyelectrolyte/polymer domains and permeate flux, was also conducted. The kinetics of H2O2 formation was discussed, along with the effects of residence time and pH on the activity of GOX. The stability and reusability of the electrostatically immobilized enzymatic system were also investigated. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800142d [article] Functionalized membranes by layer-by-layer assembly of polyelectrolytes and in situ polymerization of acrylic acid for applications in enzymatic catalysis [texte imprimé] / Saurav Datta, Auteur ; Caitlyn Cecil, Auteur ; Bhattacharyya, D., Auteur . - 2008 . - p. 4586–4597.
Bibliogr. p. 4595-4597
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4586–4597
Mots-clés : Functionalized polymeric membrane Enzymatic catalysis Layer-by-layer assembly technique Résumé : This research work was directed toward the development of highly active, stable, and reusable functionalized polymeric membrane domains for enzymatic catalysis. Functionalized membranes were created by two different approaches. In the first approach, which involved alternative attachment of cationic and anionic polyelectrolytes, functionalization was performed using a layer-by-layer (LBL) assembly technique within a nylon-based microfiltration (MF) membrane. In the second approach, a hydrophobic polyvinylidene fluoride (PVDF) MF membrane was functionalized by the in situ polymerization of acrylic acid. The enzyme, glucose oxidase (GOX), was then electrostatically immobilized inside the functionalized membrane domains to study the catalytic oxidation of glucose to gluconic acid and H2O2. Characterization of the functionalized membranes, in terms of polyelectrolyte/polymer domains and permeate flux, was also conducted. The kinetics of H2O2 formation was discussed, along with the effects of residence time and pH on the activity of GOX. The stability and reusability of the electrostatically immobilized enzymatic system were also investigated. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800142d Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4598–4606
Titre : Investigation of levulinic acid distribution from aqueous phase to organic phase with TOA extractant Type de document : texte imprimé Auteurs : Hasan Uslu, Auteur ; S. Ismail Kirbaslar, Auteur Année de publication : 2008 Article en page(s) : p. 4598–4606 Note générale : Bibliogr. p. 4605-4606 Langues : Anglais (eng) Mots-clés : Levulinic acid Trioctylamine extraction Résumé : Levulinic acid, which is a carboxylic acid with a ketone structure, is a clear to brownish semisolid; it melts at 37 C and is soluble in alcohol, ether, and chloroform. Levulinic acid can be used as an acidulant in foods and beverages. The extraction of levulinic acid with trioctylamine (TOA), dissolved in five alcohol solvents (isoamyl alcohol, hexan-1-ol, octan-1-ol, nonan-1-ol, and decan-1-ol) and two ketones (diisobutylketone (DIBK) and methylisobutylketone (MIBK)) were investigated. In addition to these amine systems, experiments were also conducted with single solvents. All measurements were performed at 298.15 K. Organic solutions of amines are being used increasingly to separate organic acids from aqueous mixture solutions via reactive extraction. The extent to which the organic phase may be loaded with levulinic acid is explained by calculating the loading ratio (T), extraction efficiency (E), and distribution coefficients (KD). Isoamyl alcohol was determined to be the most effective solvent, with a maximum distribution value of 11.303. Possible equilibrium complexation constants for acid:amine ratios of 1:1 and 2:1 have been determined, with maximum values of 6.530 and 116.608 for K11 and K21, respectively, with isoamyl alcohol. Furthermore, a linear solvation energy relationship (LSER) model equation has been obtained to calculate the distribution coefficients for alcohols, with a correlation coefficient of R2 = 0.97. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800103u [article] Investigation of levulinic acid distribution from aqueous phase to organic phase with TOA extractant [texte imprimé] / Hasan Uslu, Auteur ; S. Ismail Kirbaslar, Auteur . - 2008 . - p. 4598–4606.
Bibliogr. p. 4605-4606
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4598–4606
Mots-clés : Levulinic acid Trioctylamine extraction Résumé : Levulinic acid, which is a carboxylic acid with a ketone structure, is a clear to brownish semisolid; it melts at 37 C and is soluble in alcohol, ether, and chloroform. Levulinic acid can be used as an acidulant in foods and beverages. The extraction of levulinic acid with trioctylamine (TOA), dissolved in five alcohol solvents (isoamyl alcohol, hexan-1-ol, octan-1-ol, nonan-1-ol, and decan-1-ol) and two ketones (diisobutylketone (DIBK) and methylisobutylketone (MIBK)) were investigated. In addition to these amine systems, experiments were also conducted with single solvents. All measurements were performed at 298.15 K. Organic solutions of amines are being used increasingly to separate organic acids from aqueous mixture solutions via reactive extraction. The extent to which the organic phase may be loaded with levulinic acid is explained by calculating the loading ratio (T), extraction efficiency (E), and distribution coefficients (KD). Isoamyl alcohol was determined to be the most effective solvent, with a maximum distribution value of 11.303. Possible equilibrium complexation constants for acid:amine ratios of 1:1 and 2:1 have been determined, with maximum values of 6.530 and 116.608 for K11 and K21, respectively, with isoamyl alcohol. Furthermore, a linear solvation energy relationship (LSER) model equation has been obtained to calculate the distribution coefficients for alcohols, with a correlation coefficient of R2 = 0.97. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800103u Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4607-4616
Titre : Indirect electrochemical oxidation of p-methoxy-toluene to p-methoxy-benzaldehyde using ceric methanesulphonate : a scale-up study Type de document : texte imprimé Auteurs : V Devadoss, Auteur ; C. Ahmed Basha, Auteur ; K Jayaraman, Auteur Année de publication : 2008 Article en page(s) : p. 4607-4616 Note générale : Bibliogr. p. 4615-4616 Langues : Anglais (eng) Mots-clés : Cerium(IV) ion Indirect oxidation p-methoxy-toluene Ceric methanesulphonate Résumé : Electrochemically produced and regenerated cerium(IV) ions, by Ce3+/Ce4+, are well-known redox mediators and are used particularly as synthesis agents for the indirect oxidation of a side chain methyl group to the aldehyde group in substituted toluene. Detailed studies on indirect electrochemical oxidation of p-methoxy-toluene to p-methoxy-benzaldehyde using ceric methanesulphonate were carried out. Under optimized conditions, the yield achieved was 65-78% for the oxidation with continuous recycling and electrochemical regeneration of ceric was achieved with a current efficiency of 70-85%. Purity of the product was also remaining consistent during recycling. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071427i [article] Indirect electrochemical oxidation of p-methoxy-toluene to p-methoxy-benzaldehyde using ceric methanesulphonate : a scale-up study [texte imprimé] / V Devadoss, Auteur ; C. Ahmed Basha, Auteur ; K Jayaraman, Auteur . - 2008 . - p. 4607-4616.
Bibliogr. p. 4615-4616
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4607-4616
Mots-clés : Cerium(IV) ion Indirect oxidation p-methoxy-toluene Ceric methanesulphonate Résumé : Electrochemically produced and regenerated cerium(IV) ions, by Ce3+/Ce4+, are well-known redox mediators and are used particularly as synthesis agents for the indirect oxidation of a side chain methyl group to the aldehyde group in substituted toluene. Detailed studies on indirect electrochemical oxidation of p-methoxy-toluene to p-methoxy-benzaldehyde using ceric methanesulphonate were carried out. Under optimized conditions, the yield achieved was 65-78% for the oxidation with continuous recycling and electrochemical regeneration of ceric was achieved with a current efficiency of 70-85%. Purity of the product was also remaining consistent during recycling. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071427i Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4617-4622
Titre : Kinetic evaluation of methane-carbon dioxide reforming process based on the reaction steps Type de document : texte imprimé Auteurs : Cesar A. M Abreu, Auteur ; Douglas A Santos, Auteur ; José A Pacífico, Auteur ; Nelson M Lima Filho, Auteur Année de publication : 2008 Article en page(s) : p. 4617-4622 Note générale : Bibliogr. p. 4621-4622 Langues : Anglais (eng) Mots-clés : Methane-carbon dioxide Mass balance equations Fixed-bed reactor Résumé : Evaluations of the methane-carbon dioxide component of a carbon reforming process over a Ni/γ-Al2O3 catalyst were performed in a fixed-bed reactor at 1023, 1073, and 1123 K. The fitting of mass balance equations, including kinetic rate laws based on a mechanism proposition of three reaction steps, was formulated following experimental indications, where each step of the reaction system was individually evaluated. The comparison between experimental and calculated concentrations of the reactants and product effluents of the fixed-bed reactor leads to the estimation of the order of magnitude of the kinetic parameters corresponding to the reaction steps. The model was validated with the syngas selectivities evolutions at 943-1146 K. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071546y [article] Kinetic evaluation of methane-carbon dioxide reforming process based on the reaction steps [texte imprimé] / Cesar A. M Abreu, Auteur ; Douglas A Santos, Auteur ; José A Pacífico, Auteur ; Nelson M Lima Filho, Auteur . - 2008 . - p. 4617-4622.
Bibliogr. p. 4621-4622
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4617-4622
Mots-clés : Methane-carbon dioxide Mass balance equations Fixed-bed reactor Résumé : Evaluations of the methane-carbon dioxide component of a carbon reforming process over a Ni/γ-Al2O3 catalyst were performed in a fixed-bed reactor at 1023, 1073, and 1123 K. The fitting of mass balance equations, including kinetic rate laws based on a mechanism proposition of three reaction steps, was formulated following experimental indications, where each step of the reaction system was individually evaluated. The comparison between experimental and calculated concentrations of the reactants and product effluents of the fixed-bed reactor leads to the estimation of the order of magnitude of the kinetic parameters corresponding to the reaction steps. The model was validated with the syngas selectivities evolutions at 943-1146 K. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071546y Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4623-4631
Titre : Hydrogenation of a-methylstyrene in a piston-oscillating monolith reactor Type de document : texte imprimé Auteurs : Alan G. Bussard, Auteur ; Yogesh G. Waghmare, Auteur ; Kerry M Dooley, Auteur ; F Carl Knopf, Auteur Année de publication : 2008 Article en page(s) : p. 4623-4631 Note générale : Bibliogr. p. 4631 Langues : Anglais (eng) Mots-clés : A-methylstyrene -- hydrogenation Piston-oscillating monolith reactor Résumé : The hydrogenation of a-methylstyrene (AMS) to cumene was investigated in a novel piston-oscillating monolith reactor (POMR). Low-frequency (0-17.5 Hz) and -amplitude (2.5 mm) mechanical oscillations were applied to the three-phase system at 46 °C and 0.44 MPa of H2. For comparison purposes, the reaction was also carried out in a stirred tank at identical temperatures and pressures and at similar power input per volume. Results show activity improvements of up to 84% for 17.5 Hz, 2.5 mm piston oscillations over low-frequency gas flow pulsing conditions, and significantly greater improvements when compared to trickle beds or conventional monolith reactors. The POMR also gives as good or better selectivity toward cumene than a stirred tank at identical conditions. While the effects of catalyst pretreatment and its impact on the Pd crystallite size also have an important role in determining the catalyst activity and long-term stability in AMS hydrogenation, these results suggest that the impact of low-frequency and -amplitude oscillations, applied to structured reactors, is considerable. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701708w [article] Hydrogenation of a-methylstyrene in a piston-oscillating monolith reactor [texte imprimé] / Alan G. Bussard, Auteur ; Yogesh G. Waghmare, Auteur ; Kerry M Dooley, Auteur ; F Carl Knopf, Auteur . - 2008 . - p. 4623-4631.
Bibliogr. p. 4631
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4623-4631
Mots-clés : A-methylstyrene -- hydrogenation Piston-oscillating monolith reactor Résumé : The hydrogenation of a-methylstyrene (AMS) to cumene was investigated in a novel piston-oscillating monolith reactor (POMR). Low-frequency (0-17.5 Hz) and -amplitude (2.5 mm) mechanical oscillations were applied to the three-phase system at 46 °C and 0.44 MPa of H2. For comparison purposes, the reaction was also carried out in a stirred tank at identical temperatures and pressures and at similar power input per volume. Results show activity improvements of up to 84% for 17.5 Hz, 2.5 mm piston oscillations over low-frequency gas flow pulsing conditions, and significantly greater improvements when compared to trickle beds or conventional monolith reactors. The POMR also gives as good or better selectivity toward cumene than a stirred tank at identical conditions. While the effects of catalyst pretreatment and its impact on the Pd crystallite size also have an important role in determining the catalyst activity and long-term stability in AMS hydrogenation, these results suggest that the impact of low-frequency and -amplitude oscillations, applied to structured reactors, is considerable. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701708w Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4632-4640
Titre : Simulation of performance of cracking reactions of particle clusters in fcc risers Type de document : texte imprimé Auteurs : Shuyan Wang, Auteur ; He Yurong, Auteur ; Huilin Lu, Auteur ; Jianmian Ding, Auteur Année de publication : 2008 Article en page(s) : p. 4632-4640 Note générale : Bibliogr. p. 4639-4640 Langues : Anglais (eng) Mots-clés : Fluid catalytic cracking riser Four-lump mathematical model Cluster Résumé : The behavior of catalytic cracking reactions of particle cluster in fluid catalytic cracking risers was numerically analyzed using a four-lump mathematical model. The effects of the cluster porosity, inlet gas velocity, and cluster formation on cracking reactions were investigated. Distributions of temperature, gases, and gasoline from both the catalyst particle cluster and an isolated catalyst particle are presented. Simulated results show that the reactions from vacuum gas oil (VGO) to gasoline, gas, and coke of individual particle in the cluster are slower than those of the isolated particle, but faster for the reaction from gasoline to gas and coke. Particle clustering will reduce the reaction rates from VGO to gasoline, gas, and coke and increase the reaction rates from gasoline to gas and coke. Less gasoline is produced by particle clustering. More gas and gasoline are produced for the downward moving cluster than for the upward moving cluster. The cluster formation decreases the reaction rates and reduces gas and gasoline production. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071305q [article] Simulation of performance of cracking reactions of particle clusters in fcc risers [texte imprimé] / Shuyan Wang, Auteur ; He Yurong, Auteur ; Huilin Lu, Auteur ; Jianmian Ding, Auteur . - 2008 . - p. 4632-4640.
Bibliogr. p. 4639-4640
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4632-4640
Mots-clés : Fluid catalytic cracking riser Four-lump mathematical model Cluster Résumé : The behavior of catalytic cracking reactions of particle cluster in fluid catalytic cracking risers was numerically analyzed using a four-lump mathematical model. The effects of the cluster porosity, inlet gas velocity, and cluster formation on cracking reactions were investigated. Distributions of temperature, gases, and gasoline from both the catalyst particle cluster and an isolated catalyst particle are presented. Simulated results show that the reactions from vacuum gas oil (VGO) to gasoline, gas, and coke of individual particle in the cluster are slower than those of the isolated particle, but faster for the reaction from gasoline to gas and coke. Particle clustering will reduce the reaction rates from VGO to gasoline, gas, and coke and increase the reaction rates from gasoline to gas and coke. Less gasoline is produced by particle clustering. More gas and gasoline are produced for the downward moving cluster than for the upward moving cluster. The cluster formation decreases the reaction rates and reduces gas and gasoline production. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071305q Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4641-4647
Titre : Selective hydrogenation of benzene to cyclohexene on a Ru/Al2O3/cordierite monolithic catalyst : effect of mass transfer on the catalytic performance Type de document : texte imprimé Auteurs : Yujun Zhao, Auteur ; Jin Zhou, Auteur ; Jianguo Zhang, Auteur ; Deyi Li, Auteur Année de publication : 2008 Article en page(s) : p. 4641-4647 Note générale : Bibliogr. p. 4647 Langues : Anglais (eng) Mots-clés : Benzene -- hydrogenation Monolithic fixed-bed reactor Résumé : A Ru/Al2O3/cordierite monolithic catalyst was prepared, characterized, and examined in selective hydrogenation of benzene to cyclohexene in a monolithic fixed-bed reactor with an aqueous solution of ZnSO4. The Carberry number and Wheeler−Weisz group were calculated to analyze the effects of external and internal diffusions of H2, benzene, and cyclohexene. According to the results of calculations, the water film, solubility, and diffusion coefficients of the three reactants (H2, benzene, and cyclohexene) play important roles in the mass-transfer rate. Under proper reaction conditions, the effects of the external mass transfer of H2 and benzene on the reaction rate are negligible. For the hydrogenation of cyclohexene, the diffusion of cyclohexene from the organic phase to the catalyst is the limiting step in the presence of water, which is the most important factor for obtaining high cyclohexene selectivity. The absence of pore diffusion of the three reactants, which is attributed to the thin eggshell distribution of in the catalyst, is another important factor for the higher cyclohexene selectivity. In addition, the optimum reaction conditions were found to be 413-423 K and 5 MPa. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071574g [article] Selective hydrogenation of benzene to cyclohexene on a Ru/Al2O3/cordierite monolithic catalyst : effect of mass transfer on the catalytic performance [texte imprimé] / Yujun Zhao, Auteur ; Jin Zhou, Auteur ; Jianguo Zhang, Auteur ; Deyi Li, Auteur . - 2008 . - p. 4641-4647.
Bibliogr. p. 4647
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4641-4647
Mots-clés : Benzene -- hydrogenation Monolithic fixed-bed reactor Résumé : A Ru/Al2O3/cordierite monolithic catalyst was prepared, characterized, and examined in selective hydrogenation of benzene to cyclohexene in a monolithic fixed-bed reactor with an aqueous solution of ZnSO4. The Carberry number and Wheeler−Weisz group were calculated to analyze the effects of external and internal diffusions of H2, benzene, and cyclohexene. According to the results of calculations, the water film, solubility, and diffusion coefficients of the three reactants (H2, benzene, and cyclohexene) play important roles in the mass-transfer rate. Under proper reaction conditions, the effects of the external mass transfer of H2 and benzene on the reaction rate are negligible. For the hydrogenation of cyclohexene, the diffusion of cyclohexene from the organic phase to the catalyst is the limiting step in the presence of water, which is the most important factor for obtaining high cyclohexene selectivity. The absence of pore diffusion of the three reactants, which is attributed to the thin eggshell distribution of in the catalyst, is another important factor for the higher cyclohexene selectivity. In addition, the optimum reaction conditions were found to be 413-423 K and 5 MPa. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071574g Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4648–4657
Titre : Molecule simulation for the secondary reactions of fluid catalytic cracking gasoline by the method of structure oriented lumping combined with Monte Carlo Type de document : texte imprimé Auteurs : Bolun Yang, Auteur ; Xiaowei Zhou, Auteur ; Chun Chen, Auteur ; Jun Yuan, Auteur Année de publication : 2008 Article en page(s) : p. 4648–4657 Note générale : Bibliogr. p. 4656-4657 Langues : Anglais (eng) Mots-clés : Fluid catalytic cracking gasoline Structure oriented lumping Monte Carlo Résumé :
To overcome the drawback of the traditional lumping method, a new method constructed from structure oriented lumping (SOL) combined with Monte Carlo (MC) to simulate the secondary reactions process of fluid catalytic cracking (FCC) gasoline was developed. The SOL method was applied to represent the feedstocks and products configuration framework; then, more than 60 item reaction rules were established to produce all the reaction networks for the secondary reactions of FCC gasoline. By integral calculating each molecule reaction probability using the MC method, the product distribution thus can be obtained. Three samples of catalytic cracking gasoline, taken from the industrial FCC units of China have been used as feedstock of the simulation to check the validity of the proposed method. Some integral properties, such as average molecular weight, element compositions, and hydrocarbon compositions were predicted. The yield of upgraded gasoline, dry gas, liquefied petroleum gas (LPG), light cycle oil (LCO), heavy oil, coke, and olefin changes with extent of reaction were also simulated with this method and the predicted results agreed well with the experimental data.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800023x [article] Molecule simulation for the secondary reactions of fluid catalytic cracking gasoline by the method of structure oriented lumping combined with Monte Carlo [texte imprimé] / Bolun Yang, Auteur ; Xiaowei Zhou, Auteur ; Chun Chen, Auteur ; Jun Yuan, Auteur . - 2008 . - p. 4648–4657.
Bibliogr. p. 4656-4657
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4648–4657
Mots-clés : Fluid catalytic cracking gasoline Structure oriented lumping Monte Carlo Résumé :
To overcome the drawback of the traditional lumping method, a new method constructed from structure oriented lumping (SOL) combined with Monte Carlo (MC) to simulate the secondary reactions process of fluid catalytic cracking (FCC) gasoline was developed. The SOL method was applied to represent the feedstocks and products configuration framework; then, more than 60 item reaction rules were established to produce all the reaction networks for the secondary reactions of FCC gasoline. By integral calculating each molecule reaction probability using the MC method, the product distribution thus can be obtained. Three samples of catalytic cracking gasoline, taken from the industrial FCC units of China have been used as feedstock of the simulation to check the validity of the proposed method. Some integral properties, such as average molecular weight, element compositions, and hydrocarbon compositions were predicted. The yield of upgraded gasoline, dry gas, liquefied petroleum gas (LPG), light cycle oil (LCO), heavy oil, coke, and olefin changes with extent of reaction were also simulated with this method and the predicted results agreed well with the experimental data.En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800023x Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4658–4664
Titre : Direct reduction of sulfur dioxide to elemental sulfur with hydrogen over Sn-Zr-based catalysts Type de document : texte imprimé Auteurs : Gi Bo Han, Auteur ; No-Kuk Park, Auteur ; Suk Hoon Yoon, Auteur ; Tae Jin Lee, Auteur Année de publication : 2008 Article en page(s) : p. 4658–4664 Note générale : Bibliogr. p. 4664 Langues : Anglais (eng) Mots-clés : Sulfur dioxide Redox mechanism Conversion Résumé : We conducted the SO2 reduction with H2 over Sn−Zr-based catalysts for the direct sulfur recovery process. The reaction temperature was varied from 250 to 550 °C while using SnO2-only, ZrO2-only, and SnO2−ZrO2 (Sn/Zr = 2/1) catalysts. The highest reactivity was obtained using the SnO2−ZrO2 (Sn/Zr = 2/1) catalyst at 550 °C, for which the SO2 conversion and sulfur selectivity were 98 and 55%, respectively. Also, the following mechanistic pathway was suggested: (1) The elemental sulfur is produced by the direct conversion of SO2 according to the redox mechanism (SO2 + 2H2 → S + 2H2O). (2) The produced sulfur is partially converted into H2S with the hydrogenation (H2 + S → H2S). (3) Finally, the Claus reaction proceeds through Lewis and Brönsted acidic sites (SO2 + 2H2S → 3S + 2H2O). It was estimated that the lattice oxygen vacancies might be active sites for the redox mechanism and the Lewis and Brönsted acidic sites might be related to the pathway of the Claus reaction. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800058v [article] Direct reduction of sulfur dioxide to elemental sulfur with hydrogen over Sn-Zr-based catalysts [texte imprimé] / Gi Bo Han, Auteur ; No-Kuk Park, Auteur ; Suk Hoon Yoon, Auteur ; Tae Jin Lee, Auteur . - 2008 . - p. 4658–4664.
Bibliogr. p. 4664
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4658–4664
Mots-clés : Sulfur dioxide Redox mechanism Conversion Résumé : We conducted the SO2 reduction with H2 over Sn−Zr-based catalysts for the direct sulfur recovery process. The reaction temperature was varied from 250 to 550 °C while using SnO2-only, ZrO2-only, and SnO2−ZrO2 (Sn/Zr = 2/1) catalysts. The highest reactivity was obtained using the SnO2−ZrO2 (Sn/Zr = 2/1) catalyst at 550 °C, for which the SO2 conversion and sulfur selectivity were 98 and 55%, respectively. Also, the following mechanistic pathway was suggested: (1) The elemental sulfur is produced by the direct conversion of SO2 according to the redox mechanism (SO2 + 2H2 → S + 2H2O). (2) The produced sulfur is partially converted into H2S with the hydrogenation (H2 + S → H2S). (3) Finally, the Claus reaction proceeds through Lewis and Brönsted acidic sites (SO2 + 2H2S → 3S + 2H2O). It was estimated that the lattice oxygen vacancies might be active sites for the redox mechanism and the Lewis and Brönsted acidic sites might be related to the pathway of the Claus reaction. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800058v Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4665–4674
Titre : Comparative assessment of batch reactors for scalable hydrogen production Type de document : texte imprimé Auteurs : David L. Damm, Auteur ; Andrei G. Fedorov, Auteur Année de publication : 2008 Article en page(s) : p. 4665–4674 Note générale : Bibliogr. p. 4673-4674 Langues : Anglais (eng) Mots-clés : Batch reactors Scalable hydrogen Numerical simulation Résumé : A new concept of a variable volume batch reactor, CO2/H2 active membrane piston (CHAMP), is introduced for scalable hydrogen production for portable and distributed applications. The conceptual design and operating principles of the CHAMP reactor are discussed, aiming at precise control of residence time and optimal performance. A simplified reactor model is formulated, and the operation of the idealized reactor is numerically simulated. In the ideal limit of no heat or mass transfer limitations, the hydrogen yield rate and efficiency of the CHAMP reactor are shown to exceed that of a comparable, traditional continuous-flow (CF) design. In the presence of transport limitations, the relative performance enhancement enabled by the CHAMP reactor is even greater. Additionally, the transient nature of the CHAMP reactor makes it particularly suited for applications with varying power demands, such as in transportation, and its stackable design makes it highly scalable across a wide range of power requirements. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800294y [article] Comparative assessment of batch reactors for scalable hydrogen production [texte imprimé] / David L. Damm, Auteur ; Andrei G. Fedorov, Auteur . - 2008 . - p. 4665–4674.
Bibliogr. p. 4673-4674
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4665–4674
Mots-clés : Batch reactors Scalable hydrogen Numerical simulation Résumé : A new concept of a variable volume batch reactor, CO2/H2 active membrane piston (CHAMP), is introduced for scalable hydrogen production for portable and distributed applications. The conceptual design and operating principles of the CHAMP reactor are discussed, aiming at precise control of residence time and optimal performance. A simplified reactor model is formulated, and the operation of the idealized reactor is numerically simulated. In the ideal limit of no heat or mass transfer limitations, the hydrogen yield rate and efficiency of the CHAMP reactor are shown to exceed that of a comparable, traditional continuous-flow (CF) design. In the presence of transport limitations, the relative performance enhancement enabled by the CHAMP reactor is even greater. Additionally, the transient nature of the CHAMP reactor makes it particularly suited for applications with varying power demands, such as in transportation, and its stackable design makes it highly scalable across a wide range of power requirements. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800294y Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4675–4682
Titre : Combinatorial assessment of the activity-composition correlation for several alloy nanoparticle catalysts Type de document : texte imprimé Auteurs : Xiajing Shi, Auteur ; Jin Luo, Auteur ; Peter N. Njoki, Auteur ; Yan Lin, Auteur Année de publication : 2008 Article en page(s) : p. 4675–4682 Note générale : Bibliogr. p. 4682 Langues : Anglais (eng) Mots-clés : Nanoparticle catalysts Electrocatalytic parameters Response surface approach Résumé : The screening of catalysts with desired catalytic activity and selectivity for electrocatalytic fuel cell reactions is a time-consuming process. One approach to address this problem is to apply combinatorial analysis techniques. In this paper, we present the results of an investigation of the application of systematic statistical analysis techniques such as analysis of variance (ANOVA) analysis and regression modeling for the development of effective screening methods of bimetallic and trimetallic nanoparticle catalysts. Based on several sets of experimental data from the chosen catalysts, empirical models derived from statistical analysis techniques were first built to fit the experiment results for each of the electrocatalytic parameters such as catalytic peak current, peak potential, Tafel slope and mass activities. These parameters were expressed as a function of catalyst component proportion variables and process variables. The adequacy of the chosen models is verified with residual analysis. The catalyst properties were also analyzed using a response surface approach. The statistical analysis results from the available experiment data provided useful information to aid the understanding of the relationship between the catalyst activities and compositions, which may provide guidance for experimental design toward discovery of catalysts with desired activity and selectivity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800308h [article] Combinatorial assessment of the activity-composition correlation for several alloy nanoparticle catalysts [texte imprimé] / Xiajing Shi, Auteur ; Jin Luo, Auteur ; Peter N. Njoki, Auteur ; Yan Lin, Auteur . - 2008 . - p. 4675–4682.
Bibliogr. p. 4682
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4675–4682
Mots-clés : Nanoparticle catalysts Electrocatalytic parameters Response surface approach Résumé : The screening of catalysts with desired catalytic activity and selectivity for electrocatalytic fuel cell reactions is a time-consuming process. One approach to address this problem is to apply combinatorial analysis techniques. In this paper, we present the results of an investigation of the application of systematic statistical analysis techniques such as analysis of variance (ANOVA) analysis and regression modeling for the development of effective screening methods of bimetallic and trimetallic nanoparticle catalysts. Based on several sets of experimental data from the chosen catalysts, empirical models derived from statistical analysis techniques were first built to fit the experiment results for each of the electrocatalytic parameters such as catalytic peak current, peak potential, Tafel slope and mass activities. These parameters were expressed as a function of catalyst component proportion variables and process variables. The adequacy of the chosen models is verified with residual analysis. The catalyst properties were also analyzed using a response surface approach. The statistical analysis results from the available experiment data provided useful information to aid the understanding of the relationship between the catalyst activities and compositions, which may provide guidance for experimental design toward discovery of catalysts with desired activity and selectivity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800308h Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4683–4688
Titre : Improving selectivity of temperature-sensitive exothermal reactions with microreactor Type de document : texte imprimé Auteurs : Kai Wang, Auteur ; Yangcheng Lu, Auteur ; Huawei Shao, Auteur ; Guangsheng Luo, Auteur Année de publication : 2008 Article en page(s) : p. 4683–4688 Note générale : Bibliogr. p. 4688 Langues : Anglais (eng) Mots-clés : Temperature-sensitive exothermal reaction Cyclohexanecarboxylic acid Oleum Résumé : The selectivity of temperature-sensitive exothermal reaction, especially for a fast reaction system, is hard to control in chemical synthesis process. Traditionally, reducing the reaction temperature is applied to control byproduct. Nowadays, the confinement of the reaction temperature can be released by using microreactors. To demonstrate this, the fast exothermal reaction between cyclohexanecarboxylic acid and oleum was chosen as an experimental system in this work. An adiabatic micropore dispersion capillary reactor was developed to control the reaction selectivity at relatively high temperature. The results showed that 5−30 μm dispersed scale of oleum was reached in this microreactor, and nearly 100% selectivity was obtained at a relatively high product temperature, 50−60 °C, with 100% conversion of oleum. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800318q [article] Improving selectivity of temperature-sensitive exothermal reactions with microreactor [texte imprimé] / Kai Wang, Auteur ; Yangcheng Lu, Auteur ; Huawei Shao, Auteur ; Guangsheng Luo, Auteur . - 2008 . - p. 4683–4688.
Bibliogr. p. 4688
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4683–4688
Mots-clés : Temperature-sensitive exothermal reaction Cyclohexanecarboxylic acid Oleum Résumé : The selectivity of temperature-sensitive exothermal reaction, especially for a fast reaction system, is hard to control in chemical synthesis process. Traditionally, reducing the reaction temperature is applied to control byproduct. Nowadays, the confinement of the reaction temperature can be released by using microreactors. To demonstrate this, the fast exothermal reaction between cyclohexanecarboxylic acid and oleum was chosen as an experimental system in this work. An adiabatic micropore dispersion capillary reactor was developed to control the reaction selectivity at relatively high temperature. The results showed that 5−30 μm dispersed scale of oleum was reached in this microreactor, and nearly 100% selectivity was obtained at a relatively high product temperature, 50−60 °C, with 100% conversion of oleum. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800318q Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4689–4696
Titre : Equilibrium and kinetic studies on the hydrolysis of urea for ammonia generation in a semibatch reactor Type de document : texte imprimé Auteurs : J.N. Sahu, Auteur ; K. Mahalik, Auteur ; A. V. Patwardhan, Auteur ; B. C. Meikap, Auteur Année de publication : 2008 Article en page(s) : p. 4689–4696 Note générale : Bibliogr. p. 4695-4696 Langues : Anglais (eng) Mots-clés : Ammonia Urea hydrolysis Kinetic study Résumé : The present study is concerned with the methods and means to safely produce relatively small amounts (i.e., up to 50 kg/h) of ammonia. The equilibrium and kinetic study of urea hydrolysis was conducted in a semibatch reactor at atmospheric pressure to investigate the effects of reaction temperature, initial feed concentration, and time on ammonia production. This study reveals that conversion increases exponentially with increasing temperature but decreases slightly with increasing initial feed concentration of urea. Furthermore, the effect of time on conversion was also studied; it was found that conversion increases with increasing time. Using collision theory, the temperature dependency of the forward rate constant was determined, from which the activation energy of the reaction and the frequency factor were calculated. The activation energy and frequency factor of the urea hydrolysis reaction at atmospheric pressure were found to be 60.93 kJ/mol and 4.259 × 105 min−1, respectively. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800481z [article] Equilibrium and kinetic studies on the hydrolysis of urea for ammonia generation in a semibatch reactor [texte imprimé] / J.N. Sahu, Auteur ; K. Mahalik, Auteur ; A. V. Patwardhan, Auteur ; B. C. Meikap, Auteur . - 2008 . - p. 4689–4696.
Bibliogr. p. 4695-4696
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4689–4696
Mots-clés : Ammonia Urea hydrolysis Kinetic study Résumé : The present study is concerned with the methods and means to safely produce relatively small amounts (i.e., up to 50 kg/h) of ammonia. The equilibrium and kinetic study of urea hydrolysis was conducted in a semibatch reactor at atmospheric pressure to investigate the effects of reaction temperature, initial feed concentration, and time on ammonia production. This study reveals that conversion increases exponentially with increasing temperature but decreases slightly with increasing initial feed concentration of urea. Furthermore, the effect of time on conversion was also studied; it was found that conversion increases with increasing time. Using collision theory, the temperature dependency of the forward rate constant was determined, from which the activation energy of the reaction and the frequency factor were calculated. The activation energy and frequency factor of the urea hydrolysis reaction at atmospheric pressure were found to be 60.93 kJ/mol and 4.259 × 105 min−1, respectively. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800481z Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4697-4702
Titre : Spray coating of adsorbent with polymer latex on sand particles for fluoride removal in drinking water Type de document : texte imprimé Auteurs : Hai-Xia Wu, Auteur ; Ting-Jie Wang, Auteur ; Xiao Min Dou, Auteur ; Bei Zhao, Auteur Année de publication : 2008 Article en page(s) : p. 4697-4702 Note générale : Bibliogr. p. 4702 Langues : Anglais (eng) Mots-clés : Fe-Al-Ce adsorbent Polymer latex Spray coating Résumé : An iron-aluminum-cerium trimetal hydroxide (Fe-Al-Ce) adsorbent with an acrylic-styrene copolymer latex binder, which can cross-link and cure at room temperature, was coated on sand particles by spray coating. The adhesion of the coated layer increased with the latex/Fe-Al-Ce ratio. A suitable latex/Fe-Al-Ce ratio and thickness of coated adsorbent were determined to be 0.8 and 70 μm, respectively, giving good stability and adsorption capacity. The corresponding adsorption capacity of fluoride ions on the coated sand reached 3.46 mg/g at pH 7.0 and an initial fluoride concentration of 50 mg/L. Sand coated with Fe−Al−Ce is a potential adsorbent for use in a packed bed for fluoride removal from drinking water. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800278b [article] Spray coating of adsorbent with polymer latex on sand particles for fluoride removal in drinking water [texte imprimé] / Hai-Xia Wu, Auteur ; Ting-Jie Wang, Auteur ; Xiao Min Dou, Auteur ; Bei Zhao, Auteur . - 2008 . - p. 4697-4702.
Bibliogr. p. 4702
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4697-4702
Mots-clés : Fe-Al-Ce adsorbent Polymer latex Spray coating Résumé : An iron-aluminum-cerium trimetal hydroxide (Fe-Al-Ce) adsorbent with an acrylic-styrene copolymer latex binder, which can cross-link and cure at room temperature, was coated on sand particles by spray coating. The adhesion of the coated layer increased with the latex/Fe-Al-Ce ratio. A suitable latex/Fe-Al-Ce ratio and thickness of coated adsorbent were determined to be 0.8 and 70 μm, respectively, giving good stability and adsorption capacity. The corresponding adsorption capacity of fluoride ions on the coated sand reached 3.46 mg/g at pH 7.0 and an initial fluoride concentration of 50 mg/L. Sand coated with Fe−Al−Ce is a potential adsorbent for use in a packed bed for fluoride removal from drinking water. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800278b Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4703-4711
Titre : Biocorrosion of AISI 304 stainless steel by desulfovibrio desulfuricans in seawater Type de document : texte imprimé Auteurs : Thi My Phuc Nguyen, Auteur ; Xiaoxia Sheng, Auteur ; Yen-Peng Ting, Auteur ; Simo Olavi Pehkonen, Auteur Année de publication : 2008 Article en page(s) : p. 4703-4711 Note générale : Bibliogr. p. 4710-4711 Langues : Anglais (eng) Mots-clés : AISI 304 stainless steel Analytical techniques Polarization resistance Résumé : The corrosion behavior of AISI 304 stainless steel (SS304) in a batch system of enriched artificial seawater (EASW) in the presence of a sulfate-reducing bacteria (SRB) species (Desulfovibrio desulfuricans ATCC 27774) was investigated using analytical techniques including electrochemical impedance spectroscopy (EIS), atomic force microscopy (AFM), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). EIS analysis showed that the polarization resistance of SS304 decreased after immersion in EASW in the presence of the SRB for 14 days compared to the control sample (in the absence of SRB). The corrosion processes were simulated using equivalent circuit models, which provided electrochemical information on the liquid/surface interface for both abiotic and biotic systems. Using AFM, pits and cracks were observed on the stainless steel surface in the presence of SRB, and a thick biofilm produced by SRB was evident in SEM micrographs, which corroborated the EIS results for the explanation of the biocorrosion mechanism. XPS analysis showed changes in the chemical states at the near-surface environment and on the surface of stainless steel. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071468e [article] Biocorrosion of AISI 304 stainless steel by desulfovibrio desulfuricans in seawater [texte imprimé] / Thi My Phuc Nguyen, Auteur ; Xiaoxia Sheng, Auteur ; Yen-Peng Ting, Auteur ; Simo Olavi Pehkonen, Auteur . - 2008 . - p. 4703-4711.
Bibliogr. p. 4710-4711
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4703-4711
Mots-clés : AISI 304 stainless steel Analytical techniques Polarization resistance Résumé : The corrosion behavior of AISI 304 stainless steel (SS304) in a batch system of enriched artificial seawater (EASW) in the presence of a sulfate-reducing bacteria (SRB) species (Desulfovibrio desulfuricans ATCC 27774) was investigated using analytical techniques including electrochemical impedance spectroscopy (EIS), atomic force microscopy (AFM), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). EIS analysis showed that the polarization resistance of SS304 decreased after immersion in EASW in the presence of the SRB for 14 days compared to the control sample (in the absence of SRB). The corrosion processes were simulated using equivalent circuit models, which provided electrochemical information on the liquid/surface interface for both abiotic and biotic systems. Using AFM, pits and cracks were observed on the stainless steel surface in the presence of SRB, and a thick biofilm produced by SRB was evident in SEM micrographs, which corroborated the EIS results for the explanation of the biocorrosion mechanism. XPS analysis showed changes in the chemical states at the near-surface environment and on the surface of stainless steel. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071468e Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4712-4716
Titre : Basic amid acid-assisted synthesis of resorcinol-formaldehyde polymer and carbon nanospheres Type de document : texte imprimé Auteurs : Yong-Rong Dong, Auteur ; Norikazu Nishiyama, Auteur ; Yasuyuki Egashira, Auteur ; Korekazu Ueyama, Auteur Année de publication : 2008 Article en page(s) : p. 4712-4716 Note générale : Bibliogr. p. 4716
Langues : Anglais (eng) Mots-clés : Resorcinol/formaldehyde Amino acid Polymer nanospheres Résumé : Polymer nanospheres were synthesized through polymerization of resorcinol/formaldehyde (RF) in the presence of a basic amino acid, l-lysine, as a catalyst. The diameters of the RF polymer nanospheres can be tuned in the range of 30-650 nm by adjusting the molar ratios of l-lysine/H2O and resorcinol/H2O in the precursor solutions. The pH of l-lysine solution was reduced from 9.3 to 7.0 just after it was mixed with the RF solution, indicating that l-lysine molecules in the solution were consumed by interacting with resorcinol. As a result, particle growth rate extremely reduces. Thus, the particle size of the RF polymer was not much dependent with synthesis time. Thus, the use of l-lysine facilitates precise control of the size of the RF polymer nanospheres compared to the synthesis using an ammonia solution as a catalyst. Carbonized particles showed the same size as the RF polymer nanospheres. The resulting carbon nanospheres had mesopores and macropores with a surface area of 330-400 m2/g. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie7017417 [article] Basic amid acid-assisted synthesis of resorcinol-formaldehyde polymer and carbon nanospheres [texte imprimé] / Yong-Rong Dong, Auteur ; Norikazu Nishiyama, Auteur ; Yasuyuki Egashira, Auteur ; Korekazu Ueyama, Auteur . - 2008 . - p. 4712-4716.
Bibliogr. p. 4716
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4712-4716
Mots-clés : Resorcinol/formaldehyde Amino acid Polymer nanospheres Résumé : Polymer nanospheres were synthesized through polymerization of resorcinol/formaldehyde (RF) in the presence of a basic amino acid, l-lysine, as a catalyst. The diameters of the RF polymer nanospheres can be tuned in the range of 30-650 nm by adjusting the molar ratios of l-lysine/H2O and resorcinol/H2O in the precursor solutions. The pH of l-lysine solution was reduced from 9.3 to 7.0 just after it was mixed with the RF solution, indicating that l-lysine molecules in the solution were consumed by interacting with resorcinol. As a result, particle growth rate extremely reduces. Thus, the particle size of the RF polymer was not much dependent with synthesis time. Thus, the use of l-lysine facilitates precise control of the size of the RF polymer nanospheres compared to the synthesis using an ammonia solution as a catalyst. Carbonized particles showed the same size as the RF polymer nanospheres. The resulting carbon nanospheres had mesopores and macropores with a surface area of 330-400 m2/g. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie7017417 Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4717-4725
Titre : Enhancement of shelf life and handling properties of drug nanoparticles : nanoscale mixing of itraconazole with silica Type de document : texte imprimé Auteurs : Ganesh P Sanganwar, Auteur ; Gupta, Ram B., Auteur Année de publication : 2008 Article en page(s) : p. 4717-4725 Note générale : Bibliogr. p. 4734-4735 Langues : Anglais (eng) Mots-clés : Itraconazole -- nanoflakes Supercritical antisolvent solvent enhanced mass transfer Résumé : Nanoflakes of itraconazole, which is a poorly water-soluble antifungal drug, are produced using a procedure known as supercritical antisolvent solvent with enhanced mass transfer (SAS-EM). The nanoflakes show poor flowability and shelf life, each of which is improved by mixing with silica nanoparticles. To intimately mix at the nanoscale level, a macroscopic mixture of itraconazole nanoflakes and silica nanoparticles first is pressurized with supercritical carbon dioxide and then is rapidly depressurized through a nozzle. The rapid depressurization of the supercritical suspension (RDSS) causes deagglomeration and mixing, because of the high CO2 expansion velocity. Upon mixing, because of the presence of silica nanoparticles between itraconazole nanoflakes, growth of the drug particles during storage is avoided or reduced and the particle flow properties are improved significantly. The handling properties are characterized using properties such as the angle of repose, the compressibility index, and the Hausner ratio. Physical stability (shelf life) of the drug and drug/silica mixture is tested by storing the samples for 25 days at 90 °C. Agglomeration and growth of pure drug nanoflakes during storage leads to a substantial decrease in the dissolution rate. However, when the drug nanoflakes are mixed with silica nanoparticles, the dissolution rate remains almost constant during storage. Thus, effective deagglomeration and nanoscale mixing lead to an increase in the shelf life. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8000343 [article] Enhancement of shelf life and handling properties of drug nanoparticles : nanoscale mixing of itraconazole with silica [texte imprimé] / Ganesh P Sanganwar, Auteur ; Gupta, Ram B., Auteur . - 2008 . - p. 4717-4725.
Bibliogr. p. 4734-4735
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4717-4725
Mots-clés : Itraconazole -- nanoflakes Supercritical antisolvent solvent enhanced mass transfer Résumé : Nanoflakes of itraconazole, which is a poorly water-soluble antifungal drug, are produced using a procedure known as supercritical antisolvent solvent with enhanced mass transfer (SAS-EM). The nanoflakes show poor flowability and shelf life, each of which is improved by mixing with silica nanoparticles. To intimately mix at the nanoscale level, a macroscopic mixture of itraconazole nanoflakes and silica nanoparticles first is pressurized with supercritical carbon dioxide and then is rapidly depressurized through a nozzle. The rapid depressurization of the supercritical suspension (RDSS) causes deagglomeration and mixing, because of the high CO2 expansion velocity. Upon mixing, because of the presence of silica nanoparticles between itraconazole nanoflakes, growth of the drug particles during storage is avoided or reduced and the particle flow properties are improved significantly. The handling properties are characterized using properties such as the angle of repose, the compressibility index, and the Hausner ratio. Physical stability (shelf life) of the drug and drug/silica mixture is tested by storing the samples for 25 days at 90 °C. Agglomeration and growth of pure drug nanoflakes during storage leads to a substantial decrease in the dissolution rate. However, when the drug nanoflakes are mixed with silica nanoparticles, the dissolution rate remains almost constant during storage. Thus, effective deagglomeration and nanoscale mixing lead to an increase in the shelf life. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8000343 Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4736-4742
Titre : Expansion, morphological, and mechanical properties of starch-polystyrene foams containing various additives Type de document : texte imprimé Auteurs : Heartwin A. Pushpadass, Auteur ; Robert W. Besant, Auteur ; Milford A. Hanna, Auteur Année de publication : 2008 Article en page(s) : p. 4736-4742 Note générale : Bibliogr. p. 4742 Langues : Anglais (eng) Mots-clés : Starch− polystyrene -- expansion Azodicarbonamide Résumé : Starch and polystyrene (PS) were mixed at 70:30, 80:20, and 85:15 ratios with 0.5 and 1% talc and extruded into loose-fill packaging foams. Azodicarbonamide (ADC), at 0, 0.2, and 0.4 wt %, and citric acid, at 0, 0.25, and 0.5%, were added as blowing agents to enhance the radial expansion and functional properties of foams. As the concentration of ADC in the starch−PS mixtures was increased from 0 to 0.2%, the expansion ratios increased, and consequently the bulk densities decreased. However, with a further increase in the concentration of ADC to 0.4%, the expansion ratios dropped considerably. The effects of citric acid on radial expansion and other properties were similar to those of ADC. Compared to ADC, citric acid produced foams with higher radial expansion and correspondingly lower densities. Extrudates containing citric acid had large-sized cells, but the cell walls were structurally damaged due to degradation of starch. The spring indices of foams treated with various additives were not significantly different, indicating that spring index may not be a reliable measure of the elasticity. On the other hand, compressibility and modulus of elasticity varied depending on the starch, talc, and blowing agents. Foams extruded with ADC were superior in terms of their cushioning ability and other functional properties. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071049h [article] Expansion, morphological, and mechanical properties of starch-polystyrene foams containing various additives [texte imprimé] / Heartwin A. Pushpadass, Auteur ; Robert W. Besant, Auteur ; Milford A. Hanna, Auteur . - 2008 . - p. 4736-4742.
Bibliogr. p. 4742
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4736-4742
Mots-clés : Starch− polystyrene -- expansion Azodicarbonamide Résumé : Starch and polystyrene (PS) were mixed at 70:30, 80:20, and 85:15 ratios with 0.5 and 1% talc and extruded into loose-fill packaging foams. Azodicarbonamide (ADC), at 0, 0.2, and 0.4 wt %, and citric acid, at 0, 0.25, and 0.5%, were added as blowing agents to enhance the radial expansion and functional properties of foams. As the concentration of ADC in the starch−PS mixtures was increased from 0 to 0.2%, the expansion ratios increased, and consequently the bulk densities decreased. However, with a further increase in the concentration of ADC to 0.4%, the expansion ratios dropped considerably. The effects of citric acid on radial expansion and other properties were similar to those of ADC. Compared to ADC, citric acid produced foams with higher radial expansion and correspondingly lower densities. Extrudates containing citric acid had large-sized cells, but the cell walls were structurally damaged due to degradation of starch. The spring indices of foams treated with various additives were not significantly different, indicating that spring index may not be a reliable measure of the elasticity. On the other hand, compressibility and modulus of elasticity varied depending on the starch, talc, and blowing agents. Foams extruded with ADC were superior in terms of their cushioning ability and other functional properties. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071049h Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4743-4749
Titre : Synthesis of ZSM-5-type zeolite membranes on porous disks loaded with different amounts of seed Type de document : texte imprimé Auteurs : Eser Eser Dinçer, Auteur ; Halil Kalıpçılar, Auteur ; Ali Culfaz, Auteur Année de publication : 2008 Article en page(s) : p. 4743-4749 Note générale : Bibliogr. p. 4748-4749 Langues : Anglais (eng) Mots-clés : ZSM-5-type zeolite membranes Alumina supports Résumé : ZSM-5-type zeolite membranes were synthesized at 130 °C on alumina supports coated with seed crystals by vacuum seeding. Compact and uniform ZSM-5 layers were formed on the support surfaces when the amount of seed was less than 1 mg/cm2. Higher loading of seed crystals resulted in an asymmetric structure with a compact and uniform ZSM-5 layer on top, the support at the bottom, and the seed layer in between. Fifty-one membranes were prepared on supports coated with different amounts of seed. About 70% of the membranes synthesized on seeded supports were impermeable to nitrogen before calcination, whereas all nine membranes synthesized on plain supports were permeable to nitrogen before calcination. One-third of the membranes synthesized on seeded supports had N2/SF6 ideal selectivity higher than the quality criterion of 40 after calcination. Membranes with high N2/SF6 ideal selectivity also showed high n-C4H10/i-C4H10 separation selectivity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0715411 [article] Synthesis of ZSM-5-type zeolite membranes on porous disks loaded with different amounts of seed [texte imprimé] / Eser Eser Dinçer, Auteur ; Halil Kalıpçılar, Auteur ; Ali Culfaz, Auteur . - 2008 . - p. 4743-4749.
Bibliogr. p. 4748-4749
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4743-4749
Mots-clés : ZSM-5-type zeolite membranes Alumina supports Résumé : ZSM-5-type zeolite membranes were synthesized at 130 °C on alumina supports coated with seed crystals by vacuum seeding. Compact and uniform ZSM-5 layers were formed on the support surfaces when the amount of seed was less than 1 mg/cm2. Higher loading of seed crystals resulted in an asymmetric structure with a compact and uniform ZSM-5 layer on top, the support at the bottom, and the seed layer in between. Fifty-one membranes were prepared on supports coated with different amounts of seed. About 70% of the membranes synthesized on seeded supports were impermeable to nitrogen before calcination, whereas all nine membranes synthesized on plain supports were permeable to nitrogen before calcination. One-third of the membranes synthesized on seeded supports had N2/SF6 ideal selectivity higher than the quality criterion of 40 after calcination. Membranes with high N2/SF6 ideal selectivity also showed high n-C4H10/i-C4H10 separation selectivity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0715411 Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4726–4735
Titre : Corrosion in aqueous solution of two alkanolamines with CO2 and H2S : N-methyldiethanolamine + diethanolamine at 393 K Type de document : texte imprimé Auteurs : Rafael Eustaquio-Rincon, Auteur ; Maria Esther Rebolledo-Libreros, Auteur ; Arturo Trejo, Auteur ; René Molnar, Auteur Année de publication : 2008 Article en page(s) : p. 4726–4735 Note générale : Bibliogr. p. 4734-4735 Langues : Anglais (eng) Mots-clés : Metal corrosion Carbon steel Well-known weight loss method Résumé : In this work we have used an apparatus constructed in our laboratory to systematically study the corrosion rate on metals and evaluate specialty chemical products for preventing metal corrosion in industrial plants. We performed experimental studies on the effect of specific variables on corrosion rates over carbon steel, such as pressure, concentration of alkanolamines in aqueous solution, and amount of acid gases (CO2 and H2S). The technique utilized to evaluate the corrosion rate is the well-known weight loss method. With the experimental apparatus and method developed in this work we have determined the corrosion rate of AISI 1010 carbon steel in aqueous solutions of known concentration of N-methyldiethanolamine (MDEA) and diethanolamine (DEA), individually, with and without acid gases, and in different alkanolamine blends with total alkanolamine mass fraction in the range 15−60%, with mass ratios of MDEA/DEA of 3.5/1 and 2/1, with the addition of different amounts of H2S and CO2 at a pressure range of 276−5861 kPa (40−850 psig). Corrosion rates over carbon steel were determined in the liquid phase and also in some runs in both liquid and vapor phases, at 393.15 K. In the studied systems the corrosion rate decreases when the concentration of the alkanolamine increases. It was also possible to establish the effect of the amount of CO2 and H2S, in an individual way as well as in a mixture, on the corrosion rate of the carbon steel. The results show that corrosion rate of the alkanolamine solutions is not affected by CO2 in the range 0−0.35 mol; however, the presence of H2S drastically increases the corrosion rate as the amount of H2S increases. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071557r [article] Corrosion in aqueous solution of two alkanolamines with CO2 and H2S : N-methyldiethanolamine + diethanolamine at 393 K [texte imprimé] / Rafael Eustaquio-Rincon, Auteur ; Maria Esther Rebolledo-Libreros, Auteur ; Arturo Trejo, Auteur ; René Molnar, Auteur . - 2008 . - p. 4726–4735.
Bibliogr. p. 4734-4735
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4726–4735
Mots-clés : Metal corrosion Carbon steel Well-known weight loss method Résumé : In this work we have used an apparatus constructed in our laboratory to systematically study the corrosion rate on metals and evaluate specialty chemical products for preventing metal corrosion in industrial plants. We performed experimental studies on the effect of specific variables on corrosion rates over carbon steel, such as pressure, concentration of alkanolamines in aqueous solution, and amount of acid gases (CO2 and H2S). The technique utilized to evaluate the corrosion rate is the well-known weight loss method. With the experimental apparatus and method developed in this work we have determined the corrosion rate of AISI 1010 carbon steel in aqueous solutions of known concentration of N-methyldiethanolamine (MDEA) and diethanolamine (DEA), individually, with and without acid gases, and in different alkanolamine blends with total alkanolamine mass fraction in the range 15−60%, with mass ratios of MDEA/DEA of 3.5/1 and 2/1, with the addition of different amounts of H2S and CO2 at a pressure range of 276−5861 kPa (40−850 psig). Corrosion rates over carbon steel were determined in the liquid phase and also in some runs in both liquid and vapor phases, at 393.15 K. In the studied systems the corrosion rate decreases when the concentration of the alkanolamine increases. It was also possible to establish the effect of the amount of CO2 and H2S, in an individual way as well as in a mixture, on the corrosion rate of the carbon steel. The results show that corrosion rate of the alkanolamine solutions is not affected by CO2 in the range 0−0.35 mol; however, the presence of H2S drastically increases the corrosion rate as the amount of H2S increases. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071557r Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4750–4753
Titre : Visible-light-induced photocatalyst based on nickel titanate nanoparticles Type de document : texte imprimé Auteurs : Xin Shu, Auteur ; Jing He, Auteur ; Dong Chen, Auteur Année de publication : 2008 Article en page(s) : p. 4750–4753 Note générale : Bibliogr. p. 4752-4753 Langues : Anglais (eng) Mots-clés : Crystalline structure TiO2 NiTiO3 Photocatalytic activities Résumé : TiO2-coupled NiTiO3 nanoparticles have been prepared by coprecipitation in aqueous medium followed by sintering. Powder X-ray diffraction (PXRD) and high-resolution transmission electron microscopy (HRTEM) were used to characterize the crystalline structure. The crystalline sizes of both TiO2 and NiTiO3 were estimated to be in the range of 40−50 nm. A noticeable optical absorbance in the visible range was observed by UV−vis diffuse reflection spectroscopy (DRS). The photocatalytic activities were evaluated in the degradation of methylene blue in aqueous solution. The results show that the TiO2-coupled NiTiO3 nanoparticles exhibit good photocatalytic activities under visible light irradiation. The NiTiO3 phase was found to be indispensable for photoabsorption and photocatalysis. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071619d [article] Visible-light-induced photocatalyst based on nickel titanate nanoparticles [texte imprimé] / Xin Shu, Auteur ; Jing He, Auteur ; Dong Chen, Auteur . - 2008 . - p. 4750–4753.
Bibliogr. p. 4752-4753
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4750–4753
Mots-clés : Crystalline structure TiO2 NiTiO3 Photocatalytic activities Résumé : TiO2-coupled NiTiO3 nanoparticles have been prepared by coprecipitation in aqueous medium followed by sintering. Powder X-ray diffraction (PXRD) and high-resolution transmission electron microscopy (HRTEM) were used to characterize the crystalline structure. The crystalline sizes of both TiO2 and NiTiO3 were estimated to be in the range of 40−50 nm. A noticeable optical absorbance in the visible range was observed by UV−vis diffuse reflection spectroscopy (DRS). The photocatalytic activities were evaluated in the degradation of methylene blue in aqueous solution. The results show that the TiO2-coupled NiTiO3 nanoparticles exhibit good photocatalytic activities under visible light irradiation. The NiTiO3 phase was found to be indispensable for photoabsorption and photocatalysis. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071619d Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4754–4757
Titre : Activated carbons obtained from rice husk : influence of leaching on textural parameters Type de document : texte imprimé Auteurs : Cristina Deiana, Auteur ; Dolly Granados, Auteur ; Rosa Venturini, Auteur ; Alejandro Amaya, Auteur Année de publication : 2008 Article en page(s) : p. 4754–4757 Note générale : Bibliogr. p. 4757 Langues : Anglais (eng) Mots-clés : Activated carbons Rice husk Textural parameters Résumé : Activated carbons obtained from rice husk exhibit low specific surface areas when physical activation is applied due to its high silica content. The purpose of this work was to improve textural parameters of powdered activated carbons obtained from rice husk. To avoid the negative influence of the raw material ash content, a leaching step was included in the preparation process. Hydrofluoric acid, in two concentrations (25 and 50 wt %), was used as leaching agent and applied in different stages of the process. Physical activation using water vapor as activating agent was applied. Specific surface area and porosity were evaluated from nitrogen adsorption data. When a leaching step was included, specific surface area values between 700 and 1200 m2/g were obtained. These values are higher than that corresponding to the activated carbon prepared from rice husk not treated with acid (290 m2/g). Pore size distribution depends on the step sequence of the preparation process and on the HF concentration. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071657x [article] Activated carbons obtained from rice husk : influence of leaching on textural parameters [texte imprimé] / Cristina Deiana, Auteur ; Dolly Granados, Auteur ; Rosa Venturini, Auteur ; Alejandro Amaya, Auteur . - 2008 . - p. 4754–4757.
Bibliogr. p. 4757
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4754–4757
Mots-clés : Activated carbons Rice husk Textural parameters Résumé : Activated carbons obtained from rice husk exhibit low specific surface areas when physical activation is applied due to its high silica content. The purpose of this work was to improve textural parameters of powdered activated carbons obtained from rice husk. To avoid the negative influence of the raw material ash content, a leaching step was included in the preparation process. Hydrofluoric acid, in two concentrations (25 and 50 wt %), was used as leaching agent and applied in different stages of the process. Physical activation using water vapor as activating agent was applied. Specific surface area and porosity were evaluated from nitrogen adsorption data. When a leaching step was included, specific surface area values between 700 and 1200 m2/g were obtained. These values are higher than that corresponding to the activated carbon prepared from rice husk not treated with acid (290 m2/g). Pore size distribution depends on the step sequence of the preparation process and on the HF concentration. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071657x Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4758–4764
Titre : Batch removal of aqueous Cu2+ ions using nanoparticles of zero-valent iron : a study of the capacity and mechanism of uptake Type de document : texte imprimé Auteurs : Duygu Karabelli, Auteur ; Çagri Üzüm, Auteur ; Talal Shahwan, Auteur ; Ahmet E. Eroglu, Auteur Année de publication : 2008 Article en page(s) : p. 4758–4764 Langues : Anglais (eng) Mots-clés : Cu2+ ions Zero-valent iron X-ray photoelectron spectroscopy diffraction Résumé : In this study, nZVI prepared by borohydride reduction was applied for the removal of Cu2+ ions under a variety of experimental conditions. The uptake experiments investigated the effects of initial concentration, contact time, pH, and repetitive loading on the extent of retardation of Cu2+ ions. Within the applied conditions, the sorbent demonstrated fast uptake kinetics and outstanding fixation abilities up to an initial Cu2+ concentration of 200.0 mg/L. Partitioning of Cu2+ ions between liquid and solid phases demonstrated an isotherm of L-type. Within the studied conditions, the capacity of uptake was found to be 250 mg of Cu2+ per g of nZVI. According to X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) results, Cu2+ ions were sorbed primarily via a redox mechanism that resulted in the formation of Cu2O and Cu0. The contact of iron nanoparticles with aqueous media caused extensive formation of iron oxide. However, the material did not completely lose its removal capacity and was repeatedly applied at low concentrations for further uptake trials. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800081s [article] Batch removal of aqueous Cu2+ ions using nanoparticles of zero-valent iron : a study of the capacity and mechanism of uptake [texte imprimé] / Duygu Karabelli, Auteur ; Çagri Üzüm, Auteur ; Talal Shahwan, Auteur ; Ahmet E. Eroglu, Auteur . - 2008 . - p. 4758–4764.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4758–4764
Mots-clés : Cu2+ ions Zero-valent iron X-ray photoelectron spectroscopy diffraction Résumé : In this study, nZVI prepared by borohydride reduction was applied for the removal of Cu2+ ions under a variety of experimental conditions. The uptake experiments investigated the effects of initial concentration, contact time, pH, and repetitive loading on the extent of retardation of Cu2+ ions. Within the applied conditions, the sorbent demonstrated fast uptake kinetics and outstanding fixation abilities up to an initial Cu2+ concentration of 200.0 mg/L. Partitioning of Cu2+ ions between liquid and solid phases demonstrated an isotherm of L-type. Within the studied conditions, the capacity of uptake was found to be 250 mg of Cu2+ per g of nZVI. According to X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) results, Cu2+ ions were sorbed primarily via a redox mechanism that resulted in the formation of Cu2O and Cu0. The contact of iron nanoparticles with aqueous media caused extensive formation of iron oxide. However, the material did not completely lose its removal capacity and was repeatedly applied at low concentrations for further uptake trials. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800081s Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4765–4774
Titre : Dynamic operability analysis for stable and unstable linear processes Type de document : texte imprimé Auteurs : Herry Santoso, Auteur ; Jie Bao, Auteur ; Peter L. Lee, Auteur Année de publication : 2008 Article en page(s) : p. 4765–4774 Langues : Anglais (eng) Mots-clés : Passive systems Nonpassive process Input feedforward passivity Output feedback passivity Résumé : Dynamic operability analysis determines the achievable control performance for a given process. Based on open-loop models, such analysis is useful in revealing controllability problems in the early process design stages. This paper presents a new approach to dynamic operability analysis based on the concept of passive systems. It is well-known that passive systems are very easy to control. The lack of passivity of a nonpassive process can be quantified by using an input feedforward passivity (IFP) or an output feedback passivity (OFP) index, which measures how much feedforward/feedback is required to render the process passive. A nonminimum phase stable process usually has a shortage of IFP and thus needs a controller with an excessive OFP to ensure closed-loop stability. Excessive OFP of the controller represents the upper limit of the controller gain. Therefore, the shortage of IFP of a stable process can be used to determine its achievable performance. This analysis is then extended to unstable processes using coprime factorization. Numerical methods for dynamic operability analysis for both stable and unstable processes are developed in this paper. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070599c [article] Dynamic operability analysis for stable and unstable linear processes [texte imprimé] / Herry Santoso, Auteur ; Jie Bao, Auteur ; Peter L. Lee, Auteur . - 2008 . - p. 4765–4774.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4765–4774
Mots-clés : Passive systems Nonpassive process Input feedforward passivity Output feedback passivity Résumé : Dynamic operability analysis determines the achievable control performance for a given process. Based on open-loop models, such analysis is useful in revealing controllability problems in the early process design stages. This paper presents a new approach to dynamic operability analysis based on the concept of passive systems. It is well-known that passive systems are very easy to control. The lack of passivity of a nonpassive process can be quantified by using an input feedforward passivity (IFP) or an output feedback passivity (OFP) index, which measures how much feedforward/feedback is required to render the process passive. A nonminimum phase stable process usually has a shortage of IFP and thus needs a controller with an excessive OFP to ensure closed-loop stability. Excessive OFP of the controller represents the upper limit of the controller gain. Therefore, the shortage of IFP of a stable process can be used to determine its achievable performance. This analysis is then extended to unstable processes using coprime factorization. Numerical methods for dynamic operability analysis for both stable and unstable processes are developed in this paper. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070599c Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4775–4783
Titre : Robust online monitoring for multimode processes based on nonlinear external analysis Type de document : texte imprimé Auteurs : Zhiqiang Ge, Auteur ; Chunjie Yang, Auteur ; Zhihuan Song, Auteur Année de publication : 2008 Article en page(s) : p. 4775–4783 Langues : Anglais (eng) Mots-clés : Robust online monitoring Linear external analysis Résumé : A robust online monitoring approach based on nonlinear external analysis is proposed for monitoring multimode processes. External analysis was previously proposed to distinguish faults from normal changes in operating conditions. However, linear external analysis may not function well in nonlinear processes, in which correlations between external variables and main variables are generally nonlinear. Under the consideration of real-time monitoring, a moving window is used for sample selection and least-squares support vector regression is used as the model structure of nonlinear external analysis. When the influence of external variables is removed, the filtered information of main variables is extracted and monitored by a two-step independent component analysis−principal component analysis strategy. In addition, to improve the performance of modeling and monitoring, a robust scheme is developed. A benchmark study of the Tennessee Eastman process shows the efficiency of the proposed method. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071304y [article] Robust online monitoring for multimode processes based on nonlinear external analysis [texte imprimé] / Zhiqiang Ge, Auteur ; Chunjie Yang, Auteur ; Zhihuan Song, Auteur . - 2008 . - p. 4775–4783.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4775–4783
Mots-clés : Robust online monitoring Linear external analysis Résumé : A robust online monitoring approach based on nonlinear external analysis is proposed for monitoring multimode processes. External analysis was previously proposed to distinguish faults from normal changes in operating conditions. However, linear external analysis may not function well in nonlinear processes, in which correlations between external variables and main variables are generally nonlinear. Under the consideration of real-time monitoring, a moving window is used for sample selection and least-squares support vector regression is used as the model structure of nonlinear external analysis. When the influence of external variables is removed, the filtered information of main variables is extracted and monitored by a two-step independent component analysis−principal component analysis strategy. In addition, to improve the performance of modeling and monitoring, a robust scheme is developed. A benchmark study of the Tennessee Eastman process shows the efficiency of the proposed method. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071304y Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4784–4790
Titre : Simple robust dead-time compensator for first-order plus dead-time unstable processes Type de document : texte imprimé Auteurs : Julio E. Normey-Rico, Auteur ; Eduardo. F. Camacho, Auteur Année de publication : 2008 Article en page(s) : p. 4784–4790 Langues : Anglais (eng) Mots-clés : Unstable processes Dead time Résumé : This paper presents a simple and efficient solution to control first-order unstable processes with dead time. The controller is based on a simple modified structure of the Smith predictor that allows to cope with unstable processes and to tune the controller for a robust behavior. The proposed structure is simple to analyze and tune and gives totally decoupled disturbance rejection and set-point responses. Comparative results with some controllers recently presented in literature show the advantages of the proposed strategy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0713487 [article] Simple robust dead-time compensator for first-order plus dead-time unstable processes [texte imprimé] / Julio E. Normey-Rico, Auteur ; Eduardo. F. Camacho, Auteur . - 2008 . - p. 4784–4790.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4784–4790
Mots-clés : Unstable processes Dead time Résumé : This paper presents a simple and efficient solution to control first-order unstable processes with dead time. The controller is based on a simple modified structure of the Smith predictor that allows to cope with unstable processes and to tune the controller for a robust behavior. The proposed structure is simple to analyze and tune and gives totally decoupled disturbance rejection and set-point responses. Comparative results with some controllers recently presented in literature show the advantages of the proposed strategy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0713487 Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4791–4796
Titre : Nonlinear model identification for temperature control in single wafer rapid thermal processing Type de document : texte imprimé Auteurs : Wonhui Cho, Auteur ; Thomas F. Edgar, Auteur Année de publication : 2008 Article en page(s) : p. 4791–4796 Langues : Anglais (eng) Mots-clés : Single wafer rapid thermal processing Integrated circuits Résumé : Single wafer rapid thermal processing (RTP) has become one of the key technologies in semiconductor manufacturing due to its faster wafer processing with reduced thermal budget and precise control of processing conditions. As the standard size of the silicon wafer grows and integration of integrated circuits increases, better control to improve the processing time, uniformity, and repeatability of processing is required. In RTP, identification and control are complicated because of high nonlinearity, drift, and time varying nature of the wafer dynamics. Physical models for the wafer dynamics have been available, but they are not utilized fully for identification and control. Here, based on a physical model of wafer, a practical identification method and an analytic linearizing control method are proposed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071378%2B [article] Nonlinear model identification for temperature control in single wafer rapid thermal processing [texte imprimé] / Wonhui Cho, Auteur ; Thomas F. Edgar, Auteur . - 2008 . - p. 4791–4796.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4791–4796
Mots-clés : Single wafer rapid thermal processing Integrated circuits Résumé : Single wafer rapid thermal processing (RTP) has become one of the key technologies in semiconductor manufacturing due to its faster wafer processing with reduced thermal budget and precise control of processing conditions. As the standard size of the silicon wafer grows and integration of integrated circuits increases, better control to improve the processing time, uniformity, and repeatability of processing is required. In RTP, identification and control are complicated because of high nonlinearity, drift, and time varying nature of the wafer dynamics. Physical models for the wafer dynamics have been available, but they are not utilized fully for identification and control. Here, based on a physical model of wafer, a practical identification method and an analytic linearizing control method are proposed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071378%2B Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4797–4806
Titre : Dynamics of axially dispersed reactors Type de document : texte imprimé Auteurs : Li, Mingheng, Auteur Année de publication : 2008 Article en page(s) : p. 4797–4806 Langues : Anglais (eng) Mots-clés : Axially dispersed reactors State-space approach Proper orthogonal decomposition technique Résumé : Axially dispersed reactors with simultaneous convection, dispersion, and reaction might be used to approximate real reactors. While the steady-state solution to an axially dispersed reactor is well-described in the literature, its dynamic behavior is not often discussed. Studying this problem could provide insights into a class of industrial concentration transition problems, such as the product change in a glass melting furnace where one glass product is gradually replaced by another with a different composition. In this work, the dynamics in a tubular reactor with significant axial dispersion are explored following a state-space approach. The state-space models can be constructed either analytically or numerically. In the analytical approach, a continuous-time state-space model is derived from eigenfunction expansion followed by solving a Sturm−Liouville problem. In the numerical approach, a high-dimensional discrete-time state-space model is formulated by the discretization of the process PDE using the implicit finite-difference scheme. The proper orthogonal decomposition (POD) technique is then used to reduce the order of the state-space model. In either case, an optimal trajectory of the feed composition with bounded constraints to achieve a transition in the outlet concentration is solved based on the reduced models using quadratic programming. Computer simulations are used to demonstrate that substantial dispersions, if they exist in a reactor, can significantly affect the reactor dynamics (i.e., a long time might be required to make a concentration transition). In such a case, an optimal feed trajectory solved by dynamic optimization can be used to significantly reduce the transition time. Potential applications to the glass product transition are discussed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800083e [article] Dynamics of axially dispersed reactors [texte imprimé] / Li, Mingheng, Auteur . - 2008 . - p. 4797–4806.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4797–4806
Mots-clés : Axially dispersed reactors State-space approach Proper orthogonal decomposition technique Résumé : Axially dispersed reactors with simultaneous convection, dispersion, and reaction might be used to approximate real reactors. While the steady-state solution to an axially dispersed reactor is well-described in the literature, its dynamic behavior is not often discussed. Studying this problem could provide insights into a class of industrial concentration transition problems, such as the product change in a glass melting furnace where one glass product is gradually replaced by another with a different composition. In this work, the dynamics in a tubular reactor with significant axial dispersion are explored following a state-space approach. The state-space models can be constructed either analytically or numerically. In the analytical approach, a continuous-time state-space model is derived from eigenfunction expansion followed by solving a Sturm−Liouville problem. In the numerical approach, a high-dimensional discrete-time state-space model is formulated by the discretization of the process PDE using the implicit finite-difference scheme. The proper orthogonal decomposition (POD) technique is then used to reduce the order of the state-space model. In either case, an optimal trajectory of the feed composition with bounded constraints to achieve a transition in the outlet concentration is solved based on the reduced models using quadratic programming. Computer simulations are used to demonstrate that substantial dispersions, if they exist in a reactor, can significantly affect the reactor dynamics (i.e., a long time might be required to make a concentration transition). In such a case, an optimal feed trajectory solved by dynamic optimization can be used to significantly reduce the transition time. Potential applications to the glass product transition are discussed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800083e Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4807–4816
Titre : A methodology to determine controllability indices in the frequency domain Type de document : texte imprimé Auteurs : Mate Gabor, Auteur ; Péter Mizsey, Auteur Année de publication : 2008 Article en page(s) : p. 4807–4816 Langues : Anglais (eng) Mots-clés : Frequency domain -- controllability indices Open loop simulations State space representation Résumé : The control structure design is an important step of process synthesis. This activity can be supported with controllability indices of the process to be designed. Existing methods to calculate these indices are very complicated and time consuming. In this article, a methodology is presented for the simple determination of controllability indices in the frequency domain. With this methodology, the process of making open loop simulations to approximate transfer function matrices can be avoided. The results obtained can be used to evaluate different control structures. The methodology uses the Control Design Interface module of Aspen Dynamics to describe the system with the linear state space representation. The state space representation can be transferred into Matlab that is used to calculate the controllability indices in the function of frequency from the matrices transferred. The methodology is introduced on two thermally coupled distillation systems (side-stream stripper, SS, and side-stream rectifier, SR). The results show that the methodology is well applicable. The SS has better controllability properties than the SR if the BC separation is easier than AB. In the other cases the SR is better. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070952e [article] A methodology to determine controllability indices in the frequency domain [texte imprimé] / Mate Gabor, Auteur ; Péter Mizsey, Auteur . - 2008 . - p. 4807–4816.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4807–4816
Mots-clés : Frequency domain -- controllability indices Open loop simulations State space representation Résumé : The control structure design is an important step of process synthesis. This activity can be supported with controllability indices of the process to be designed. Existing methods to calculate these indices are very complicated and time consuming. In this article, a methodology is presented for the simple determination of controllability indices in the frequency domain. With this methodology, the process of making open loop simulations to approximate transfer function matrices can be avoided. The results obtained can be used to evaluate different control structures. The methodology uses the Control Design Interface module of Aspen Dynamics to describe the system with the linear state space representation. The state space representation can be transferred into Matlab that is used to calculate the controllability indices in the function of frequency from the matrices transferred. The methodology is introduced on two thermally coupled distillation systems (side-stream stripper, SS, and side-stream rectifier, SR). The results show that the methodology is well applicable. The SS has better controllability properties than the SR if the BC separation is easier than AB. In the other cases the SR is better. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070952e Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4817–4829
Titre : Design and optimization of indirect energy storage systems for batch process plants Type de document : texte imprimé Auteurs : Cheng-Liang Chen, Auteur ; Ying-Jyuan Ciou, Auteur Année de publication : 2008 Article en page(s) : p. 4817–4829 Langues : Anglais (eng) Mots-clés : Indirect heat exchange network Thermal storage policy Batch plant Résumé : One of the main difficulties for handling heat integration problems in batch plants is the time-dependent existence of hot/cold process streams during time period p. This article aims at proposing a generic method for synthesizing an indirect heat exchange network and its associated thermal storage policy for targeting the external utility in a batch plant. Therein, a heat transfer medium (HTM), originally staying in a cold tank, is used to absorb surplus heat from hot process streams, and the HTM with elevated temperature is temporarily stored in a hot tank. The accumulated hot HTM is then utilized to heat subsequent cold process streams, and the cooled HTM recirculates back into its source cold tank. The limitation of heat interchange between time-dependent hot/cold process streams can be relaxed by applying the recirculated heat transfer medium to carry out indirect thermal storage. A superstructure is proposed and the mathematical programming approach is applied for investigating the indirect heat exchange policy. Not using any heuristics that are based on the concepts of pinch limitations, the proposed superstructure-based representation for synthesis of indirect heat exchange networks (HEN’s) for batch processes is formulated as a mixed-integer nonlinear program (MINLP). Numerical examples are explored to demonstrate the applicability of proposed indirect HEN synthesis method for batch processes. This method is verified by two examples with different numbers of storage tanks. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0710667 [article] Design and optimization of indirect energy storage systems for batch process plants [texte imprimé] / Cheng-Liang Chen, Auteur ; Ying-Jyuan Ciou, Auteur . - 2008 . - p. 4817–4829.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4817–4829
Mots-clés : Indirect heat exchange network Thermal storage policy Batch plant Résumé : One of the main difficulties for handling heat integration problems in batch plants is the time-dependent existence of hot/cold process streams during time period p. This article aims at proposing a generic method for synthesizing an indirect heat exchange network and its associated thermal storage policy for targeting the external utility in a batch plant. Therein, a heat transfer medium (HTM), originally staying in a cold tank, is used to absorb surplus heat from hot process streams, and the HTM with elevated temperature is temporarily stored in a hot tank. The accumulated hot HTM is then utilized to heat subsequent cold process streams, and the cooled HTM recirculates back into its source cold tank. The limitation of heat interchange between time-dependent hot/cold process streams can be relaxed by applying the recirculated heat transfer medium to carry out indirect thermal storage. A superstructure is proposed and the mathematical programming approach is applied for investigating the indirect heat exchange policy. Not using any heuristics that are based on the concepts of pinch limitations, the proposed superstructure-based representation for synthesis of indirect heat exchange networks (HEN’s) for batch processes is formulated as a mixed-integer nonlinear program (MINLP). Numerical examples are explored to demonstrate the applicability of proposed indirect HEN synthesis method for batch processes. This method is verified by two examples with different numbers of storage tanks. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0710667 Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4830–4844
Titre : Effects of relative volatility ranking on design and control of reactive distillation systems with ternary decomposition reactions Type de document : texte imprimé Auteurs : Chin-Shih Chen, Auteur ; Cheng-Ching Yu, Auteur Année de publication : 2008 Article en page(s) : p. 4830–4844 Langues : Anglais (eng) Mots-clés : Reactive distillation systems One-column configuration Two-column configuration Résumé : Design and control of reactive distillation systems of ternary decomposition reactions with two different relative volatility rankings, IK ↔ LK + HK and HK ↔ LK + IK, have been explored. Systems with intermediate boiling reactant have a behavior that is similar to that of the quaternary system with intermediate boiling reactants, if not simpler. Systems with heavy reactant are quite different. Two possible flowsheets (two-column and one-column configurations) have been discussed. The two-column flowsheet is workable for a wide range of chemical equilibrium constants. The one-column configuration is feasible for systems with high chemical equilibrium constants. Economical comparisons reveal that the one-column configuration is preferred for systems with large equilibrium constants while the two-column configuration is more economical in the region of low equilibrium constants. For the control of nonlinear reactive distillation systems, fast measurement (temperature measurement) is essential for tight control. Control performance deteriorates if significant measurement delay is present. Thus, parallel cascade control offers an attractive alternative for the control of reactive distillation systems in an offset free manner. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701787e [article] Effects of relative volatility ranking on design and control of reactive distillation systems with ternary decomposition reactions [texte imprimé] / Chin-Shih Chen, Auteur ; Cheng-Ching Yu, Auteur . - 2008 . - p. 4830–4844.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4830–4844
Mots-clés : Reactive distillation systems One-column configuration Two-column configuration Résumé : Design and control of reactive distillation systems of ternary decomposition reactions with two different relative volatility rankings, IK ↔ LK + HK and HK ↔ LK + IK, have been explored. Systems with intermediate boiling reactant have a behavior that is similar to that of the quaternary system with intermediate boiling reactants, if not simpler. Systems with heavy reactant are quite different. Two possible flowsheets (two-column and one-column configurations) have been discussed. The two-column flowsheet is workable for a wide range of chemical equilibrium constants. The one-column configuration is feasible for systems with high chemical equilibrium constants. Economical comparisons reveal that the one-column configuration is preferred for systems with large equilibrium constants while the two-column configuration is more economical in the region of low equilibrium constants. For the control of nonlinear reactive distillation systems, fast measurement (temperature measurement) is essential for tight control. Control performance deteriorates if significant measurement delay is present. Thus, parallel cascade control offers an attractive alternative for the control of reactive distillation systems in an offset free manner. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701787e Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4845–4860
Titre : Integrated operational planning and medium-term scheduling for large-scale industrial batch plants Type de document : texte imprimé Auteurs : Peter M. Verderame, Auteur ; Christodoulos A. Floudas, Auteur Année de publication : 2008 Article en page(s) : p. 4845–4860 Langues : Anglais (eng) Mots-clés : Batch chemical plants Planning Scheduling Integrative framework Résumé : The operational planning and the medium-term scheduling of a multipurpose and multiproduct batch chemical plant are inter-related activities that involve the allocation of plant resources. Because of their disparate time scales, however, the effective integration of planning and scheduling has proven to be a formidable task. The lack of an integrative framework for planning and scheduling will invariably cause the planning model to provide unrealistic production targets to the scheduling level, leading to the misallocation of plant resources. In response to this issue, a novel framework for the integration of planning and scheduling for a multipurpose and multiproduct batch plant is presented. The framework entails integrating a novel planning with production disaggregation model with a medium-term scheduling model through a forward-rolling horizon approach. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8001414 [article] Integrated operational planning and medium-term scheduling for large-scale industrial batch plants [texte imprimé] / Peter M. Verderame, Auteur ; Christodoulos A. Floudas, Auteur . - 2008 . - p. 4845–4860.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4845–4860
Mots-clés : Batch chemical plants Planning Scheduling Integrative framework Résumé : The operational planning and the medium-term scheduling of a multipurpose and multiproduct batch chemical plant are inter-related activities that involve the allocation of plant resources. Because of their disparate time scales, however, the effective integration of planning and scheduling has proven to be a formidable task. The lack of an integrative framework for planning and scheduling will invariably cause the planning model to provide unrealistic production targets to the scheduling level, leading to the misallocation of plant resources. In response to this issue, a novel framework for the integration of planning and scheduling for a multipurpose and multiproduct batch plant is presented. The framework entails integrating a novel planning with production disaggregation model with a medium-term scheduling model through a forward-rolling horizon approach. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8001414 Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4861–4869
Titre : Numerical simulation of multiphase flow and collision humidification in the multifluid alkaline spray generator for a novel semidry flue gas desulfurization system Type de document : texte imprimé Auteurs : Yuegui Zhou, Auteur ; Weicheng Cao, Auteur ; Lei Wang, Auteur ; Mingchuan Zhang, Auteur Année de publication : 2008 Article en page(s) : p. 4861–4869 Langues : Anglais (eng) Mots-clés : Multifluid alkaline spray generator Multiphase flow Desulfurization system Résumé : A hybrid Eulerian−Lagrangian model was developed to simulate gas−droplet−particle multiphase flow and the collision humidification between sorbent particles and spray droplets in the confined multifluid alkaline spray generator for a novel semidry flue gas desulfurization system. In this model, the motions of discrete phases were tracked simultaneously by using a stochastic trajectory approach, and a probability model of droplets catching particles was presented to judge whether sorbent particles were caught with direct simulation Monte Carlo method. Numerical humidification efficiency of sorbent particles is validated by the experimental one deduced from the measured desulfurization efficiency. And the effects of flue gas flow rate, spray droplet diameter, sorbent particle diameter, and particle injection location on the humidification efficiency were optimized. Numerical results show that the collision humidification efficiency of sorbent particles increases significantly at the axial distance of 1.67 times the generator diameter from the nozzle tip and reaches 78.5% without recirculation flow in the alkaline spray generator when the ratio of flue gas mass flow rate to spray water mass flow rate is 6.7. Moreover, there is an optimal droplet diameter ranging from 125 to 150 µm and an optimal particle injection location corresponding to the maximum humidification efficiency in this paper. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071494c [article] Numerical simulation of multiphase flow and collision humidification in the multifluid alkaline spray generator for a novel semidry flue gas desulfurization system [texte imprimé] / Yuegui Zhou, Auteur ; Weicheng Cao, Auteur ; Lei Wang, Auteur ; Mingchuan Zhang, Auteur . - 2008 . - p. 4861–4869.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4861–4869
Mots-clés : Multifluid alkaline spray generator Multiphase flow Desulfurization system Résumé : A hybrid Eulerian−Lagrangian model was developed to simulate gas−droplet−particle multiphase flow and the collision humidification between sorbent particles and spray droplets in the confined multifluid alkaline spray generator for a novel semidry flue gas desulfurization system. In this model, the motions of discrete phases were tracked simultaneously by using a stochastic trajectory approach, and a probability model of droplets catching particles was presented to judge whether sorbent particles were caught with direct simulation Monte Carlo method. Numerical humidification efficiency of sorbent particles is validated by the experimental one deduced from the measured desulfurization efficiency. And the effects of flue gas flow rate, spray droplet diameter, sorbent particle diameter, and particle injection location on the humidification efficiency were optimized. Numerical results show that the collision humidification efficiency of sorbent particles increases significantly at the axial distance of 1.67 times the generator diameter from the nozzle tip and reaches 78.5% without recirculation flow in the alkaline spray generator when the ratio of flue gas mass flow rate to spray water mass flow rate is 6.7. Moreover, there is an optimal droplet diameter ranging from 125 to 150 µm and an optimal particle injection location corresponding to the maximum humidification efficiency in this paper. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071494c Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4870–4882
Titre : Quantitative application of in situ ATR-FTIR and Raman spectroscopy in crystallization processes Type de document : texte imprimé Auteurs : Jeroen Cornel, Auteur ; Christian Lindenberg, Auteur ; Mazzotti, Marco, Auteur Année de publication : 2008 Article en page(s) : p. 4870–4882 Langues : Anglais (eng) Mots-clés : Fourier transform infrared Raman spectroscopy Crystallization processe Résumé : In this work, different process analytical technologies based on vibrational spectroscopy, i.e., attenuated total reflectance Fourier transform infrared (ATR-FTIR) and Raman spectroscopy, were applied by means of multivariate data analysis techniques. Wide applicability has been demonstrated by in situ monitoring of various crystallization processes, e.g., solubility curve measurement, cooling crystallization, and solvent-mediated polymorph transformation. A calibration strategy has been proposed to obtain accurate and robust estimations of the solute concentration by ATR-FTIR monitoring. Different calibration models and preprocessing techniques were applied and compared. It was shown that these methods allow for solute concentration monitoring of nonisothermal processes even for sparingly soluble substances such as l-glutamic acid in an aqueous environment. An extensive study has been performed to identify the underlying process parameters that influence the Raman signal, i.e., solid composition, solute concentration, suspension density, particle size and shape, and temperature. It is demonstrated that principal component analysis provides qualitative information for seeded and unseeded polymorphic transformations and enables end-point determination of a solid-state transformation process using l-glutamic acid. The multivariate calibration approach described in this work allows for quantitative application of Raman spectroscopy to a multiphase multicomponent dynamic process such as a solvent-mediated polymorphic transformation. Additionally, it was shown that multivariate analysis of Raman data allows for solute concentration estimation despite the fact that solute signals are weak and completely overlapping with signals related to the solid phase. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800236v [article] Quantitative application of in situ ATR-FTIR and Raman spectroscopy in crystallization processes [texte imprimé] / Jeroen Cornel, Auteur ; Christian Lindenberg, Auteur ; Mazzotti, Marco, Auteur . - 2008 . - p. 4870–4882.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4870–4882
Mots-clés : Fourier transform infrared Raman spectroscopy Crystallization processe Résumé : In this work, different process analytical technologies based on vibrational spectroscopy, i.e., attenuated total reflectance Fourier transform infrared (ATR-FTIR) and Raman spectroscopy, were applied by means of multivariate data analysis techniques. Wide applicability has been demonstrated by in situ monitoring of various crystallization processes, e.g., solubility curve measurement, cooling crystallization, and solvent-mediated polymorph transformation. A calibration strategy has been proposed to obtain accurate and robust estimations of the solute concentration by ATR-FTIR monitoring. Different calibration models and preprocessing techniques were applied and compared. It was shown that these methods allow for solute concentration monitoring of nonisothermal processes even for sparingly soluble substances such as l-glutamic acid in an aqueous environment. An extensive study has been performed to identify the underlying process parameters that influence the Raman signal, i.e., solid composition, solute concentration, suspension density, particle size and shape, and temperature. It is demonstrated that principal component analysis provides qualitative information for seeded and unseeded polymorphic transformations and enables end-point determination of a solid-state transformation process using l-glutamic acid. The multivariate calibration approach described in this work allows for quantitative application of Raman spectroscopy to a multiphase multicomponent dynamic process such as a solvent-mediated polymorphic transformation. Additionally, it was shown that multivariate analysis of Raman data allows for solute concentration estimation despite the fact that solute signals are weak and completely overlapping with signals related to the solid phase. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800236v Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4883–4890
Titre : Reducing the cost of CO2 capture from flue gases using pressure swing adsorption Type de document : texte imprimé Auteurs : Minh T. Ho, Auteur ; Guy W. Allinson, Auteur ; Dianne E. Wiley, Auteur Année de publication : 2008 Article en page(s) : p. 4883–4890 Langues : Anglais (eng) Mots-clés : Gas separation Pressure swing adsorption Sensitivity analysis Résumé : Pressure swing adsorption (PSA) processes have been used extensively for gas separation, especially in the separation of hydrogen from CO2, and in air purification. The objective of this paper is to examine the economic feasibility of pressure swing adsorption (PSA) for recovering CO2 from postcombustion power plant flue gas. The analysis considers both high-pressure feed and vacuum desorption using commercial adsorbent 13X, which has a working capacity of 2.2 mol/kg and CO2/N2 selectivity of 54. The results show that using vacuum desorption reduces the capture cost from US$57 to US$51 per ton of CO2 avoided and is comparable in cost to CO2 capture using conventional MEA absorption of US$49 per ton of CO2 avoided. In this paper, a sensitivity analysis is also presented showing the effect on the capture cost with changes in process cycle; feed pressure and evacuation pressure; improvements the adsorbent characteristics; and selectivity and working capacity. The results show that a hypothetical adsorbent with a working capacity of 4.3 mol/kg and a CO2/N2 selectivity of 150 can reduce the capture cost to US$30 per ton of CO2 avoided. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070831e [article] Reducing the cost of CO2 capture from flue gases using pressure swing adsorption [texte imprimé] / Minh T. Ho, Auteur ; Guy W. Allinson, Auteur ; Dianne E. Wiley, Auteur . - 2008 . - p. 4883–4890.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4883–4890
Mots-clés : Gas separation Pressure swing adsorption Sensitivity analysis Résumé : Pressure swing adsorption (PSA) processes have been used extensively for gas separation, especially in the separation of hydrogen from CO2, and in air purification. The objective of this paper is to examine the economic feasibility of pressure swing adsorption (PSA) for recovering CO2 from postcombustion power plant flue gas. The analysis considers both high-pressure feed and vacuum desorption using commercial adsorbent 13X, which has a working capacity of 2.2 mol/kg and CO2/N2 selectivity of 54. The results show that using vacuum desorption reduces the capture cost from US$57 to US$51 per ton of CO2 avoided and is comparable in cost to CO2 capture using conventional MEA absorption of US$49 per ton of CO2 avoided. In this paper, a sensitivity analysis is also presented showing the effect on the capture cost with changes in process cycle; feed pressure and evacuation pressure; improvements the adsorbent characteristics; and selectivity and working capacity. The results show that a hypothetical adsorbent with a working capacity of 4.3 mol/kg and a CO2/N2 selectivity of 150 can reduce the capture cost to US$30 per ton of CO2 avoided. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070831e Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4891–4897
Titre : Adsorption of lead(II) ion from aqueous solution using rice hull ash Type de document : texte imprimé Auteurs : Li-Hua Wang, Auteur ; Chun-I Lin, Auteur Année de publication : 2008 Article en page(s) : p. 4891–4897 Langues : Anglais (eng) Mots-clés : Lead(II) ion -- adsorption Rice hull ash Aqueous solution Résumé : Adsorption of lead(II) ion from aqueous solution using rice hull ash (RHA) was explored in this work. The RHA prepared was found to be an efficient adsorbent. Experimental results indicated the rate of removal and the removal at equilibrium could be increased by increasing the initial lead concentration, pH, stroke speed, or adsorption temperature. They were also found to be increased by decreasing RHA dosage. The effects of RHA dosage and initial lead concentration were found to be pronounced, while those of pH, stroke speed, and adsorption temperature were less significant. The data of adsorption kinetics indicated the process was physisorption controlled and the pseudo-second-order rate equation suitably interpreted the overall process. An empirical relationship between lead adsorption and time was also determined. En ligne : pubs.acs.org/doi/abs/10.1021/ie071521z [article] Adsorption of lead(II) ion from aqueous solution using rice hull ash [texte imprimé] / Li-Hua Wang, Auteur ; Chun-I Lin, Auteur . - 2008 . - p. 4891–4897.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4891–4897
Mots-clés : Lead(II) ion -- adsorption Rice hull ash Aqueous solution Résumé : Adsorption of lead(II) ion from aqueous solution using rice hull ash (RHA) was explored in this work. The RHA prepared was found to be an efficient adsorbent. Experimental results indicated the rate of removal and the removal at equilibrium could be increased by increasing the initial lead concentration, pH, stroke speed, or adsorption temperature. They were also found to be increased by decreasing RHA dosage. The effects of RHA dosage and initial lead concentration were found to be pronounced, while those of pH, stroke speed, and adsorption temperature were less significant. The data of adsorption kinetics indicated the process was physisorption controlled and the pseudo-second-order rate equation suitably interpreted the overall process. An empirical relationship between lead adsorption and time was also determined. En ligne : pubs.acs.org/doi/abs/10.1021/ie071521z Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4898–4904
Titre : Gas transport through nano poly(ethylene-co-vinyl acetate) composite membranes Type de document : texte imprimé Auteurs : S. Anil Kumar, Auteur ; He Yuelong, Auteur ; Ding Yumei, Auteur ; Yang Le, Auteur Année de publication : 2008 Article en page(s) : p. 4898–4904 Langues : Anglais (eng) Mots-clés : Nano poly(ethylene-co-vinyl acetate) Composite membranes Gas transport Résumé : Poly(ethylene-co-vinyl acetate)−clay nanocomposites containing different filler loading were prepared. Transport of gases through the composite membranes was investigated, and the results were compared with the unfilled one. Transport studies revealed that gas transport was considerably reduced by the incorporation of clay filler into the polymer matrix especially at a loading of 3 wt % filler. It was also found that permeability increased for composites containing more than 3 wt %. This is presumably due to aggregation of clay filler at higher loading. The morphology of nanocomposites was analyzed by X-ray diffraction and transmission electron microscopy. Dielectric loss data were also used to understand the uniformity of dispersion of nanoparticles. The effect of free volume on transport behavior was investigated by positron lifetime spectroscopic analysis. The cross-link density values were estimated to correlate with the gas barrier properties. The oxygen/nitrogen selectivity of these membranes was investigated. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071624h [article] Gas transport through nano poly(ethylene-co-vinyl acetate) composite membranes [texte imprimé] / S. Anil Kumar, Auteur ; He Yuelong, Auteur ; Ding Yumei, Auteur ; Yang Le, Auteur . - 2008 . - p. 4898–4904.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4898–4904
Mots-clés : Nano poly(ethylene-co-vinyl acetate) Composite membranes Gas transport Résumé : Poly(ethylene-co-vinyl acetate)−clay nanocomposites containing different filler loading were prepared. Transport of gases through the composite membranes was investigated, and the results were compared with the unfilled one. Transport studies revealed that gas transport was considerably reduced by the incorporation of clay filler into the polymer matrix especially at a loading of 3 wt % filler. It was also found that permeability increased for composites containing more than 3 wt %. This is presumably due to aggregation of clay filler at higher loading. The morphology of nanocomposites was analyzed by X-ray diffraction and transmission electron microscopy. Dielectric loss data were also used to understand the uniformity of dispersion of nanoparticles. The effect of free volume on transport behavior was investigated by positron lifetime spectroscopic analysis. The cross-link density values were estimated to correlate with the gas barrier properties. The oxygen/nitrogen selectivity of these membranes was investigated. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071624h Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4905–4908
Titre : A new method for synthesis of Mg−Al, Mg−Fe, and Zn−Al layered double hydroxides and their uptake properties of bromide ion Type de document : texte imprimé Auteurs : Ramesh Chitrakar, Auteur ; Satoko Tezuka, Auteur ; Akinari Sonoda, Auteur ; Kohji Sakane, Auteur Année de publication : 2008 Article en page(s) : p. 4905–4908 Langues : Anglais (eng) Mots-clés : Layered double hydroxides Bromide ion Résumé : We report a very simple and efficient method to prepare LDHs of Mg−Al, Mg−Fe, and Zn−Al by simply mixing solid divalent metal oxide with trivalent metal chloride solution at 30 °C. Calcined Mg−Al and Mg−Fe are effective in removing low concentration of Br− from a mixed solution (Br− = 0.1 mmol/dm3, Cl− = 1.0 mmol/dm3) at a material dose of 1 g/dm3. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0716417 [article] A new method for synthesis of Mg−Al, Mg−Fe, and Zn−Al layered double hydroxides and their uptake properties of bromide ion [texte imprimé] / Ramesh Chitrakar, Auteur ; Satoko Tezuka, Auteur ; Akinari Sonoda, Auteur ; Kohji Sakane, Auteur . - 2008 . - p. 4905–4908.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4905–4908
Mots-clés : Layered double hydroxides Bromide ion Résumé : We report a very simple and efficient method to prepare LDHs of Mg−Al, Mg−Fe, and Zn−Al by simply mixing solid divalent metal oxide with trivalent metal chloride solution at 30 °C. Calcined Mg−Al and Mg−Fe are effective in removing low concentration of Br− from a mixed solution (Br− = 0.1 mmol/dm3, Cl− = 1.0 mmol/dm3) at a material dose of 1 g/dm3. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0716417 Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4909–4916
Titre : Properties of nanosize zinc titanium desulfurization sorbents promoted with iron and cerium oxides Type de document : texte imprimé Auteurs : Suk Yong Jung, Auteur ; Lee, Jae-Soo, Auteur ; Jung Je Park, Auteur ; Soo Chool Lee, Auteur Année de publication : 2008 Article en page(s) : p. 4909–4916 Langues : Anglais (eng) Mots-clés : Zn− Ti desulfurization sorbents Absorption Regeneration Résumé : To improve the sulfidation and regeneration properties of Zn−Ti-based desulfurization sorbents, sorbents with 5 wt % of the promoters, iron or cerium oxide, were prepared and tested in a packed reactor under intermediate temperature conditions (H2S absorption at 480 °C, regeneration at 580 °C). These sorbents showed excellent sulfur-removing capacities without deactivation even after 10 cycles of absorption and regeneration. Their regeneration properties were also improved by the iron and cerium promoters. In the case of the iron promoter, heat was released when the metal sulfide was converted to the metal oxide, which improved the regeneration property of the Zn−Ti-based sorbent. In the case of the cerium promoter, there was no reaction with hydrogen sulfide gases, and the spent Zn−Ti-based sorbent was easily regenerated by virtue of the OSC (oxygen storage capacity) property of the cerium promoter, which easily converted the S of ZnS to SO2. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071357f [article] Properties of nanosize zinc titanium desulfurization sorbents promoted with iron and cerium oxides [texte imprimé] / Suk Yong Jung, Auteur ; Lee, Jae-Soo, Auteur ; Jung Je Park, Auteur ; Soo Chool Lee, Auteur . - 2008 . - p. 4909–4916.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4909–4916
Mots-clés : Zn− Ti desulfurization sorbents Absorption Regeneration Résumé : To improve the sulfidation and regeneration properties of Zn−Ti-based desulfurization sorbents, sorbents with 5 wt % of the promoters, iron or cerium oxide, were prepared and tested in a packed reactor under intermediate temperature conditions (H2S absorption at 480 °C, regeneration at 580 °C). These sorbents showed excellent sulfur-removing capacities without deactivation even after 10 cycles of absorption and regeneration. Their regeneration properties were also improved by the iron and cerium promoters. In the case of the iron promoter, heat was released when the metal sulfide was converted to the metal oxide, which improved the regeneration property of the Zn−Ti-based sorbent. In the case of the cerium promoter, there was no reaction with hydrogen sulfide gases, and the spent Zn−Ti-based sorbent was easily regenerated by virtue of the OSC (oxygen storage capacity) property of the cerium promoter, which easily converted the S of ZnS to SO2. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071357f Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4917–4923
Titre : Modelling of the batch sucrose crystallization kinetics using artificial neural networks : comparison with conventional regression analysis Type de document : texte imprimé Auteurs : K. Vasanth Kumar, Auteur ; P. Martins, Auteur ; F. Rocha, Auteur Année de publication : 2008 Article en page(s) : p. 4917–4923 Langues : Anglais (eng) Mots-clés : Sucrose Artificial neural network Correlation Résumé : A three-layer feed-forward artificial neural network (ANN) was constructed and tested to analyze the crystal growth rate of sucrose under different operating conditions. The operating variables studied were used as inputs to predict the corresponding crystal growth rate. The operating variables studied include the supersaturation, temperature, agitation speed, and seed crystal diameter. The constructed ANN was determined to be precise in modeling the crystal growth rate for any operating conditions. The constructed network was also found to be precise in predicting the crystal growth rate for the new input data, which are kept unaware of the trained neural network, showing its applicability to determine the growth rate for any operating conditions of interest. The ANN-predicted crystal growth rates were compared to those from the conventional nonlinear regression analysis. The ANN was observed to be more accurate in predicting the crystal growth rate, irrespective of the operating conditions studied. The correlation coefficients between the experimentally determined crystal growth rate and the crystal growth rates determined by the ANN and multiple nonlinear regression (MNLR) were determined to be 0.999 and 0.748, respectively. The correlation coefficient between the experimentally determined crystal growth rates and the crystal growth rates determined by the ANN for new inputs was observed to be >0.98. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701706v [article] Modelling of the batch sucrose crystallization kinetics using artificial neural networks : comparison with conventional regression analysis [texte imprimé] / K. Vasanth Kumar, Auteur ; P. Martins, Auteur ; F. Rocha, Auteur . - 2008 . - p. 4917–4923.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4917–4923
Mots-clés : Sucrose Artificial neural network Correlation Résumé : A three-layer feed-forward artificial neural network (ANN) was constructed and tested to analyze the crystal growth rate of sucrose under different operating conditions. The operating variables studied were used as inputs to predict the corresponding crystal growth rate. The operating variables studied include the supersaturation, temperature, agitation speed, and seed crystal diameter. The constructed ANN was determined to be precise in modeling the crystal growth rate for any operating conditions. The constructed network was also found to be precise in predicting the crystal growth rate for the new input data, which are kept unaware of the trained neural network, showing its applicability to determine the growth rate for any operating conditions of interest. The ANN-predicted crystal growth rates were compared to those from the conventional nonlinear regression analysis. The ANN was observed to be more accurate in predicting the crystal growth rate, irrespective of the operating conditions studied. The correlation coefficients between the experimentally determined crystal growth rate and the crystal growth rates determined by the ANN and multiple nonlinear regression (MNLR) were determined to be 0.999 and 0.748, respectively. The correlation coefficient between the experimentally determined crystal growth rates and the crystal growth rates determined by the ANN for new inputs was observed to be >0.98. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701706v Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4924–4928
Titre : Decolorization of biopetroleum and analysis of colored components Type de document : texte imprimé Auteurs : Jinhua Li, Auteur ; Chao Wang, Auteur ; Zhengyu Yang, Auteur Année de publication : 2008 Article en page(s) : p. 4924–4928 Langues : Anglais (eng) Mots-clés : Biopetroleum Decolorization Distillation fractions Résumé : Biopetroleum, mainly composed of alkanes, cycloalkanes, and aromatic hydrocarbons, was prepared from biomass by direct deoxyliquefaction. The distillation fractions were obtained after distilling at different temperatures and may become dark brown in color after storage in air. To produce a visually high-grade fuel, acid-activated bentonite was selected as the adsorbent to remove the color-induced components, such as unsaturated carbonyl groups, polycyclic aromatic hydrocarbons, quinones, heterocyclic and nitrous compounds, which can be determined by using GC/MS. The raw and acid-activated bentonites were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TG) and Fourier transform infrared (FTIR) spectra, respectively. The colored distillation fractions were decolorized by acid-activated bentonite. The results showed that the acid-activated bentonite was effective in removing the color-induced components from the distillation fractions, and the maximum decolorization efficiency was 86.31%. The adsorption equilibrium data were fitted to the Freundlich isotherm equation. Moreover, the product treated by the acid-activated bentonite proved to be a high-grade fuel, which is similar to −10# diesel oil (freezing point ≤ −10 °C), not only in composition but also in color. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800101j [article] Decolorization of biopetroleum and analysis of colored components [texte imprimé] / Jinhua Li, Auteur ; Chao Wang, Auteur ; Zhengyu Yang, Auteur . - 2008 . - p. 4924–4928.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4924–4928
Mots-clés : Biopetroleum Decolorization Distillation fractions Résumé : Biopetroleum, mainly composed of alkanes, cycloalkanes, and aromatic hydrocarbons, was prepared from biomass by direct deoxyliquefaction. The distillation fractions were obtained after distilling at different temperatures and may become dark brown in color after storage in air. To produce a visually high-grade fuel, acid-activated bentonite was selected as the adsorbent to remove the color-induced components, such as unsaturated carbonyl groups, polycyclic aromatic hydrocarbons, quinones, heterocyclic and nitrous compounds, which can be determined by using GC/MS. The raw and acid-activated bentonites were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TG) and Fourier transform infrared (FTIR) spectra, respectively. The colored distillation fractions were decolorized by acid-activated bentonite. The results showed that the acid-activated bentonite was effective in removing the color-induced components from the distillation fractions, and the maximum decolorization efficiency was 86.31%. The adsorption equilibrium data were fitted to the Freundlich isotherm equation. Moreover, the product treated by the acid-activated bentonite proved to be a high-grade fuel, which is similar to −10# diesel oil (freezing point ≤ −10 °C), not only in composition but also in color. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800101j Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4929–4936
Titre : Integral identification of continuous-time delay systems in the presence of unknown initial conditions and disturbances from step tests Type de document : texte imprimé Auteurs : Qing-Guo Wang, Auteur ; Liu, Min, Auteur ; Chang Chieh Hang, Auteur Année de publication : 2008 Article en page(s) : p. 4929–4936 Langues : Anglais (eng) Mots-clés : Continuous-time delay systems -- integral identification method Static disturbance Résumé : In this paper, an integral identification method is proposed for continuous-time delay systems in presence of both unknown initial conditions and static disturbances from a step test. The integration limits are specifically chosen to make the resulting integral equation independent of the unknown initial conditions. This enables identification of the process model from a step test by one-stage least-squares algorithm without any iteration. The proposed identification method is demonstrated through numerical simulation and real time testing. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071532s [article] Integral identification of continuous-time delay systems in the presence of unknown initial conditions and disturbances from step tests [texte imprimé] / Qing-Guo Wang, Auteur ; Liu, Min, Auteur ; Chang Chieh Hang, Auteur . - 2008 . - p. 4929–4936.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4929–4936
Mots-clés : Continuous-time delay systems -- integral identification method Static disturbance Résumé : In this paper, an integral identification method is proposed for continuous-time delay systems in presence of both unknown initial conditions and static disturbances from a step test. The integration limits are specifically chosen to make the resulting integral equation independent of the unknown initial conditions. This enables identification of the process model from a step test by one-stage least-squares algorithm without any iteration. The proposed identification method is demonstrated through numerical simulation and real time testing. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071532s Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4937–4943
Titre : Regression analysis study on the carbon dioxide capture process Type de document : texte imprimé Auteurs : Q. Zhou, Auteur ; Christine W. Chan, Auteur ; P. Tontiwachiwuthikul, Auteur Année de publication : 2008 Article en page(s) : p. 4937–4943 Langues : Anglais (eng) Mots-clés : CO2 capture Solvent concentration Regression technique Résumé : Research on amine-based carbon dioxide (CO2) capture has mainly focused on improving the effectiveness and efficiency of the CO2 capture process. The objective of our work is to explore relationships among key parameters that affect the CO2 production rate. From a survey of relevant literature, we observed that the significant parameters influencing the CO2 production rate include the reboiler heat duty, solvent concentration, solvent circulation rate, and CO2 lean loading. While it is widely recognized that these parameters are related, the exact nature of the relationships are unknown. This paper presents a regression study conducted with data collected at the International Test Center for CO2 capture (ITC) located at University of Regina, Saskatchewan, Canada. The regression technique was applied to a data set consisting of data on 113 days of operation of the CO2 capture plant, and four mathematical models of the key parameters have been developed. The models can be used for predicting the performance of the plant when changes occur in the process. By manipulation of the parameter values, the efficiency of the CO2 capture process can be improved. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701747f [article] Regression analysis study on the carbon dioxide capture process [texte imprimé] / Q. Zhou, Auteur ; Christine W. Chan, Auteur ; P. Tontiwachiwuthikul, Auteur . - 2008 . - p. 4937–4943.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4937–4943
Mots-clés : CO2 capture Solvent concentration Regression technique Résumé : Research on amine-based carbon dioxide (CO2) capture has mainly focused on improving the effectiveness and efficiency of the CO2 capture process. The objective of our work is to explore relationships among key parameters that affect the CO2 production rate. From a survey of relevant literature, we observed that the significant parameters influencing the CO2 production rate include the reboiler heat duty, solvent concentration, solvent circulation rate, and CO2 lean loading. While it is widely recognized that these parameters are related, the exact nature of the relationships are unknown. This paper presents a regression study conducted with data collected at the International Test Center for CO2 capture (ITC) located at University of Regina, Saskatchewan, Canada. The regression technique was applied to a data set consisting of data on 113 days of operation of the CO2 capture plant, and four mathematical models of the key parameters have been developed. The models can be used for predicting the performance of the plant when changes occur in the process. By manipulation of the parameter values, the efficiency of the CO2 capture process can be improved. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701747f Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4944–4952
Titre : Effect of macroinstabilities in single- and multiple-impeller stirred tanks Type de document : texte imprimé Auteurs : Alessandro Paglianti, Auteur ; Zuohua Liu, Auteur ; Giuseppina Montante, Auteur ; Franco Magelli, Auteur Année de publication : 2008 Article en page(s) : p. 4944–4952 Langues : Anglais (eng) Mots-clés : Macroinstabilities Stirred tanks Résumé : In this work, a simplified analysis of the features of macroinstabilities in stirred tanks is proposed. The experimental part of the study is based on the collection of time series acquired by pressure transducers placed on the tank wall. The measurements are not invasive, because of the probe position, and they can be easily performed in laboratory and in industrial equipment, due to the instrumentation characteristics. With respect to previous investigations, the experimental analysis is extended from Rushton and pitched-blade turbines to Chemineer BT-6 and the effect of multiple impellers (MIs) is considered. The MI presence, frequency, velocity, and strength are obtained from the analysis of the collected pressure time traces; simplified correlations for their prediction are proposed. Finally, the dynamic pressure components associated to the MIs are presented, and a simplified model to assess their importance with respect to those produced by the blade passage frequency is suggested. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800253u [article] Effect of macroinstabilities in single- and multiple-impeller stirred tanks [texte imprimé] / Alessandro Paglianti, Auteur ; Zuohua Liu, Auteur ; Giuseppina Montante, Auteur ; Franco Magelli, Auteur . - 2008 . - p. 4944–4952.
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4944–4952
Mots-clés : Macroinstabilities Stirred tanks Résumé : In this work, a simplified analysis of the features of macroinstabilities in stirred tanks is proposed. The experimental part of the study is based on the collection of time series acquired by pressure transducers placed on the tank wall. The measurements are not invasive, because of the probe position, and they can be easily performed in laboratory and in industrial equipment, due to the instrumentation characteristics. With respect to previous investigations, the experimental analysis is extended from Rushton and pitched-blade turbines to Chemineer BT-6 and the effect of multiple impellers (MIs) is considered. The MI presence, frequency, velocity, and strength are obtained from the analysis of the collected pressure time traces; simplified correlations for their prediction are proposed. Finally, the dynamic pressure components associated to the MIs are presented, and a simplified model to assess their importance with respect to those produced by the blade passage frequency is suggested. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800253u Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4953–4961
Titre : Prediction of hydrodynamic properties of mixed-particle systems and theoretical analysis of loop pressure profile in a CFB unit Type de document : texte imprimé Auteurs : Mitali Das, Auteur ; B. C. Meikap, Auteur ; R. K. Saha, Auteur Année de publication : 2008 Article en page(s) : p. 4953–4961 Note générale : Bibliogr. p. 4961 Langues : Anglais (eng) Mots-clés : Mixed particle systems Circulating fluidized bed Hydrodynamic properties Résumé : The hydrodynamic behaviors of mixed system of particles were investigated in a circulating fluidized bed (CFB) unit consisting of fast column (riser) with an inner diameter of 0.1016 m and a height of 5.62 m. Particle mixtures containing a Geldart group-A-like fluid catalytic cracking (FCC) catalyst with group-B-like sand and iron ore with coal were used to study the hydrodynamic features including static pressure, voidage, and loop pressure profile. The mixed system consisting of FCC catalyst and sand contained 20, 50, and 80 mass % sand, and the coal−iron ore mixture contained 80 mass % coal. The superficial air velocity ranged between 2.01 and 4.681 m/s, and the corresponding mass fluxes were 12.5−50 kg/(m2 s). A comparison of the available experimental values for static pressure profiles at different operating conditions for mixed-particle systems shows good agreement with those predicted from the single-particle systems. Using experimental data on the loop pressure balance, a simplified theoretical analysis was performed to predict the pressure profile in the CFB loop. The deviations between the two sets of values are within reasonable limits of accuracy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800477w [article] Prediction of hydrodynamic properties of mixed-particle systems and theoretical analysis of loop pressure profile in a CFB unit [texte imprimé] / Mitali Das, Auteur ; B. C. Meikap, Auteur ; R. K. Saha, Auteur . - 2008 . - p. 4953–4961.
Bibliogr. p. 4961
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4953–4961
Mots-clés : Mixed particle systems Circulating fluidized bed Hydrodynamic properties Résumé : The hydrodynamic behaviors of mixed system of particles were investigated in a circulating fluidized bed (CFB) unit consisting of fast column (riser) with an inner diameter of 0.1016 m and a height of 5.62 m. Particle mixtures containing a Geldart group-A-like fluid catalytic cracking (FCC) catalyst with group-B-like sand and iron ore with coal were used to study the hydrodynamic features including static pressure, voidage, and loop pressure profile. The mixed system consisting of FCC catalyst and sand contained 20, 50, and 80 mass % sand, and the coal−iron ore mixture contained 80 mass % coal. The superficial air velocity ranged between 2.01 and 4.681 m/s, and the corresponding mass fluxes were 12.5−50 kg/(m2 s). A comparison of the available experimental values for static pressure profiles at different operating conditions for mixed-particle systems shows good agreement with those predicted from the single-particle systems. Using experimental data on the loop pressure balance, a simplified theoretical analysis was performed to predict the pressure profile in the CFB loop. The deviations between the two sets of values are within reasonable limits of accuracy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800477w Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4962–4965
Titre : Nickel catalyst stability toward carboxylic acids Type de document : texte imprimé Auteurs : Andrew D. Pienaar, Auteur ; Arno de Klerk, Auteur Année de publication : 2008 Article en page(s) : p. 4962–4965 Note générale : Bibliogr. p. 4965 Langues : Anglais (eng) Mots-clés : Nickel catalysts Carboxylic acids Résumé : Reduced (unsulfided) nickel catalysts can be used for hydroprocessing sulfur-free Fischer−Tropsch derived feed materials, but catalyst deactivation by metal leaching can be a problem in the presence of carboxylic acids. Leaching of reduced nickel catalysts by carboxylic acids takes place by the formation of nickel carboxylates. Carboxylic acid leaching of nickel can be prevented by operating above the carboxylate decomposition temperature, which was found to be in the range 280−305 °C for the C2−C5 nickel carboxylates. Unfortunately this is not industrially practical, because of the hydrogenolysis propensity of reduced nickel catalysts at these conditions. It was also found that nickel leaching did not monotonically increase with temperature, but was inhibited at >200 °C, probably due to polymerization of the nickel carboxylates. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071628m [article] Nickel catalyst stability toward carboxylic acids [texte imprimé] / Andrew D. Pienaar, Auteur ; Arno de Klerk, Auteur . - 2008 . - p. 4962–4965.
Bibliogr. p. 4965
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4962–4965
Mots-clés : Nickel catalysts Carboxylic acids Résumé : Reduced (unsulfided) nickel catalysts can be used for hydroprocessing sulfur-free Fischer−Tropsch derived feed materials, but catalyst deactivation by metal leaching can be a problem in the presence of carboxylic acids. Leaching of reduced nickel catalysts by carboxylic acids takes place by the formation of nickel carboxylates. Carboxylic acid leaching of nickel can be prevented by operating above the carboxylate decomposition temperature, which was found to be in the range 280−305 °C for the C2−C5 nickel carboxylates. Unfortunately this is not industrially practical, because of the hydrogenolysis propensity of reduced nickel catalysts at these conditions. It was also found that nickel leaching did not monotonically increase with temperature, but was inhibited at >200 °C, probably due to polymerization of the nickel carboxylates. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071628m Exemplaires
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inIndustrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4966–4970
Titre : A mathematical model based on artificial neural network technique for estimating liquid water-hydrate equilibrium of water-hydrocarbon system Type de document : texte imprimé Auteurs : Amir H. Mohammadi, Auteur ; Dominique Richon, Auteur Année de publication : 2008 Article en page(s) : p. 4966–4970 Note générale : Bibliogr. p. 4970 Langues : Anglais (eng) Mots-clés : Artificial neural network technique Hydrocarbon hydrate -- solubility Résumé : A mathematical model based on feed-forward artificial neural network technique, which uses a modified Levenberg−Marquardt optimization algorithm, has been developed to estimate the solubility of a pure hydrocarbon hydrate former in pure water being in equilibrium with gas hydrates. More recent and reliable data for three hydrocarbon hydrate formers (methane, ethane, and propane) have been used to train and develop this model. Independent experimental data (not employed in training and testing) have been used to examine the reliability of this technique. The acceptable agreement between the predicted and experimental data demonstrates the capability of the neural network model for estimating the solubility of pure hydrocarbon hydrate formers in pure water being in equilibrium with gas hydrates. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800235m [article] A mathematical model based on artificial neural network technique for estimating liquid water-hydrate equilibrium of water-hydrocarbon system [texte imprimé] / Amir H. Mohammadi, Auteur ; Dominique Richon, Auteur . - 2008 . - p. 4966–4970.
Bibliogr. p. 4970
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4966–4970
Mots-clés : Artificial neural network technique Hydrocarbon hydrate -- solubility Résumé : A mathematical model based on feed-forward artificial neural network technique, which uses a modified Levenberg−Marquardt optimization algorithm, has been developed to estimate the solubility of a pure hydrocarbon hydrate former in pure water being in equilibrium with gas hydrates. More recent and reliable data for three hydrocarbon hydrate formers (methane, ethane, and propane) have been used to train and develop this model. Independent experimental data (not employed in training and testing) have been used to examine the reliability of this technique. The acceptable agreement between the predicted and experimental data demonstrates the capability of the neural network model for estimating the solubility of pure hydrocarbon hydrate formers in pure water being in equilibrium with gas hydrates. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800235m Exemplaires
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