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Bubble size and frequency in corrugated - wall bubbling fluidized beds — image analysis and neural network correlations / A. N. Khan Wardag in Industrial & engineering chemistry research, Vol. 51 N° 37 (Septembre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 37 (Septembre 2012) . - pp. 12107–12116 Titre : Bubble size and frequency in corrugated - wall bubbling fluidized beds — image analysis and neural network correlations Type de document : texte imprimé Auteurs : A. N. Khan Wardag, Auteur ; F. Larachi, Auteur ; B.P.A. Grandjean, Auteur Année de publication : 2012 Article en page(s) : pp. 12107–12116 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Bubbling  dynamics Résumé : Digital image analysis was implemented to monitor bubbling dynamics in corrugated-wall bubbling fluidized beds (CWBFB) loaded with Geldart D particles. Various geometrical configurations were investigated in terms of corrugation angle, interwall clearance, and rest bed height and gas superficial velocity. Implementation of wall corrugation led to improved gas–solid fluidization quality with respect to flat-wall bubbling fluidized beds (FWBFB) as measured in terms of retreat of the onset of bubbling as a function of gas flow rate, of reduction of bubble sizes and rise velocities, and of increase of bubble frequency. Two artificial neural network correlations valid both for FWBFB and CWBFB were recommended for estimation of bubble frequency and size using a common set of independent variables, that is, gas superficial-minimum bubbling velocity ratio, bed rest height, corrugation angle, average clearance, and vertical location. The bubble frequency explicit correlation accounted additionally for interwall minimum clearance and distance between side wall and either neck or hip of front plate, at a given elevation, whereas bubble size correlation needed bubble frequency as a supplementary input variable. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3007775 [article] Bubble size and frequency in corrugated - wall bubbling fluidized beds — image analysis and neural network correlations [texte imprimé] / A. N. Khan Wardag, Auteur ; F. Larachi, Auteur ; B.P.A. Grandjean, Auteur . - 2012 . - pp. 12107–12116. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 37 (Septembre 2012) . - pp. 12107–12116 Mots-clés : Bubbling  dynamics Résumé : Digital image analysis was implemented to monitor bubbling dynamics in corrugated-wall bubbling fluidized beds (CWBFB) loaded with Geldart D particles. Various geometrical configurations were investigated in terms of corrugation angle, interwall clearance, and rest bed height and gas superficial velocity. Implementation of wall corrugation led to improved gas–solid fluidization quality with respect to flat-wall bubbling fluidized beds (FWBFB) as measured in terms of retreat of the onset of bubbling as a function of gas flow rate, of reduction of bubble sizes and rise velocities, and of increase of bubble frequency. Two artificial neural network correlations valid both for FWBFB and CWBFB were recommended for estimation of bubble frequency and size using a common set of independent variables, that is, gas superficial-minimum bubbling velocity ratio, bed rest height, corrugation angle, average clearance, and vertical location. The bubble frequency explicit correlation accounted additionally for interwall minimum clearance and distance between side wall and either neck or hip of front plate, at a given elevation, whereas bubble size correlation needed bubble frequency as a supplementary input variable. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3007775

Comparative simulations of cobalt- and iron-based Fischer-Tropsch synthesis slurry bubble column reactors / I. Iliuta in Industrial & engineering chemistry research, Vol. 47 n°11 (Juin 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°11 (Juin 2008) . - p. 3861–3869 Titre : Comparative simulations of cobalt- and iron-based Fischer-Tropsch synthesis slurry bubble column reactors Type de document : texte imprimé Auteurs : I. Iliuta, Auteur ; F. Larachi, Auteur ; J. Anfray, Auteur ; N. Dromard, Auteur Année de publication : 2008 Article en page(s) : p. 3861–3869 Note générale : Bibliogr. p. 3869 Langues : Anglais (eng) Mots-clés : Iron;  Cobalt;  Fischer-Tropsch  synthesis Résumé : The influence of the catalyst type (Fe and Co) on CO and H2 conversions, CO2 selectivity, and the composition in Fischer-Tropsch synthesis slurry bubble column reactors was simulated for representative commercial-scale units (7 m i.d. and 30 m height). A nonisothermal, core-annulus multicompartment multicomponent two-bubble class model was used to account for a relatively detailed hydrodynamics. It was coupled to comprehensive Fischer-Tropsch synthesis and water−gas-shift reactions, in addition to descriptions of thermodynamics and thermal effects, variable gas flow rate due to chemical/physical contraction, and gas and slurry backmixing and (re)circulation. Two mechanistic kinetic models with consideration of olefin readsorption were employed to describe the paraffin and olefin formation with cobalt- and iron-based catalysts, in addition to relatively large activities for CO2 and oxygenate formation, mainly alcohols, for the latter catalyst. The influence of the temperature and superficial gas velocity on CO and H2 conversions was more evident for a cobalt-based catalyst. For both catalysts, the space-dependent superficial gas velocity directly affected the gas-phase mean residence time, influencing in the return reactor temperature and conversions. Reliable estimation of the gas velocity due to chemical contraction was critical for conversions exceeding 50%. For both catalysts, the nonisothermal simulations reveal that, because heat removal is well managed from the heat-exchange area, the reactor operation can be considered as nearly isothermal. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701764y [article] Comparative simulations of cobalt- and iron-based Fischer-Tropsch synthesis slurry bubble column reactors [texte imprimé] / I. Iliuta, Auteur ; F. Larachi, Auteur ; J. Anfray, Auteur ; N. Dromard, Auteur . - 2008 . - p. 3861–3869. Bibliogr. p. 3869 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°11 (Juin 2008) . - p. 3861–3869 Mots-clés : Iron;  Cobalt;  Fischer-Tropsch  synthesis Résumé : The influence of the catalyst type (Fe and Co) on CO and H2 conversions, CO2 selectivity, and the composition in Fischer-Tropsch synthesis slurry bubble column reactors was simulated for representative commercial-scale units (7 m i.d. and 30 m height). A nonisothermal, core-annulus multicompartment multicomponent two-bubble class model was used to account for a relatively detailed hydrodynamics. It was coupled to comprehensive Fischer-Tropsch synthesis and water−gas-shift reactions, in addition to descriptions of thermodynamics and thermal effects, variable gas flow rate due to chemical/physical contraction, and gas and slurry backmixing and (re)circulation. Two mechanistic kinetic models with consideration of olefin readsorption were employed to describe the paraffin and olefin formation with cobalt- and iron-based catalysts, in addition to relatively large activities for CO2 and oxygenate formation, mainly alcohols, for the latter catalyst. The influence of the temperature and superficial gas velocity on CO and H2 conversions was more evident for a cobalt-based catalyst. For both catalysts, the space-dependent superficial gas velocity directly affected the gas-phase mean residence time, influencing in the return reactor temperature and conversions. Reliable estimation of the gas velocity due to chemical contraction was critical for conversions exceeding 50%. For both catalysts, the nonisothermal simulations reveal that, because heat removal is well managed from the heat-exchange area, the reactor operation can be considered as nearly isothermal. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701764y

Dimethyl ether synthesis with in situ H2O removal in fixed-bed membrane reactor: model and simulations / I. Iliuta in Industrial & engineering chemistry research, Vol. 49 N° 15 (Août 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 15 (Août 2010) . - pp 6870–6877 Titre : Dimethyl ether synthesis with in situ H2O removal in fixed-bed membrane reactor: model and simulations Type de document : texte imprimé Auteurs : I. Iliuta, Auteur ; F. Larachi, Auteur ; P. Fongarland, Auteur Année de publication : 2010 Article en page(s) : pp 6870–6877 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Dimethyl  ether  Membrane  reactor. Résumé : The potential and limits of in situ removal of water under dimethyl ether (DME) synthesis conditions in a fixed-bed membrane reactor were studied numerically. The motivation for in situ H2O removal during DME synthesis by means of hydrophilic membranes is to displace the water−gas shift equilibrium to enhance conversion of CO2 into methanol to improve DME productivity. In CO-rich feeds, methanol yield/selectivity increases/decreases slowly with increasing H2O permeance because only small amounts of water are removed from the system. Methanol dehydration is not inhibited by water, and DME selectivity is not improved significantly with increasing H2O permeance. When CO is gradually replaced with CO2, with the increase of H2O membrane permeance and H2O removal, methanol yield and DME selectivity are favored and the fraction of unconverted methanol is reduced as the dehydration reaction is accelerated due to reduced kinetic inhibition by H2O. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901726u [article] Dimethyl ether synthesis with in situ H2O removal in fixed-bed membrane reactor: model and simulations [texte imprimé] / I. Iliuta, Auteur ; F. Larachi, Auteur ; P. Fongarland, Auteur . - 2010 . - pp 6870–6877. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 15 (Août 2010) . - pp 6870–6877 Mots-clés : Dimethyl  ether  Membrane  reactor. Résumé : The potential and limits of in situ removal of water under dimethyl ether (DME) synthesis conditions in a fixed-bed membrane reactor were studied numerically. The motivation for in situ H2O removal during DME synthesis by means of hydrophilic membranes is to displace the water−gas shift equilibrium to enhance conversion of CO2 into methanol to improve DME productivity. In CO-rich feeds, methanol yield/selectivity increases/decreases slowly with increasing H2O permeance because only small amounts of water are removed from the system. Methanol dehydration is not inhibited by water, and DME selectivity is not improved significantly with increasing H2O permeance. When CO is gradually replaced with CO2, with the increase of H2O membrane permeance and H2O removal, methanol yield and DME selectivity are favored and the fraction of unconverted methanol is reduced as the dehydration reaction is accelerated due to reduced kinetic inhibition by H2O. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901726u

Energy and hydrogen coproduction from (Athabasca bitumen) coke gasification with CO2 capture / S. Nourouzi-Lavasani in Industrial & engineering chemistry research, Vol. 47 N°18 (Septembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 7118–7129 Titre : Energy and hydrogen coproduction from (Athabasca bitumen) coke gasification with CO2 capture Type de document : texte imprimé Auteurs : S. Nourouzi-Lavasani, Auteur ; F. Larachi, Auteur ; M. Benali, Auteur Année de publication : 2008 Article en page(s) : p. 7118–7129 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Athabasca  bitumen  coke  CO2  capture Résumé : Performance and economic assessments of exploitation of Athabasca bitumen coke (ABC) have been conducted to alleviate the dependence toward natural gas in bitumen recovery and upgrading. Power and hydrogen production from ABC-fed integrated gasification with combined cycle (IGCC) with CO2 capture or sequestration islands, namely, CO2 physical absorption in the Selexol process and CO2 mineral trapping (MT) with Ca(II)-bearing natural brines from local aquifers, have been analyzed. Simulations show that production costs of power (electricity and heat) and H2 from the IGCC/Selexol process are 0.0584 $/kWhe, 0.046 $/kWhh, and 1.4 $/kg H2, which could be competitive with current natural gas technologies. IGCC/Selexol outperforms the IGCC/MT process, which is reflected in larger production costs for power and H2 due to the cost of the pH-controlling reagents. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800773a [article] Energy and hydrogen coproduction from (Athabasca bitumen) coke gasification with CO2 capture [texte imprimé] / S. Nourouzi-Lavasani, Auteur ; F. Larachi, Auteur ; M. Benali, Auteur . - 2008 . - p. 7118–7129. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 7118–7129 Mots-clés : Athabasca  bitumen  coke  CO2  capture Résumé : Performance and economic assessments of exploitation of Athabasca bitumen coke (ABC) have been conducted to alleviate the dependence toward natural gas in bitumen recovery and upgrading. Power and hydrogen production from ABC-fed integrated gasification with combined cycle (IGCC) with CO2 capture or sequestration islands, namely, CO2 physical absorption in the Selexol process and CO2 mineral trapping (MT) with Ca(II)-bearing natural brines from local aquifers, have been analyzed. Simulations show that production costs of power (electricity and heat) and H2 from the IGCC/Selexol process are 0.0584 $/kWhe, 0.046 $/kWhh, and 1.4 $/kg H2, which could be competitive with current natural gas technologies. IGCC/Selexol outperforms the IGCC/MT process, which is reflected in larger production costs for power and H2 due to the cost of the pH-controlling reagents. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800773a

Kinetic model for the reversible hydration of carbon dioxide catalyzed by human carbonic anhydrase II / F. Larachi in Industrial & engineering chemistry research, Vol. 49 N° 19 (Octobre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 19 (Octobre 2010) . - pp. 9095–9104 Titre : Kinetic model for the reversible hydration of carbon dioxide catalyzed by human carbonic anhydrase II Type de document : texte imprimé Auteurs : F. Larachi, Auteur Année de publication : 2010 Article en page(s) : pp. 9095–9104 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetic  Hydration  carbon  dioxide Résumé : Four variants of the two-step Ping Pong mechanism for the reversible hydration of carbon dioxide to bicarbonate catalyzed by free human carbonic anhydrase II (HCA II) in solutions were derived and their goodness-of-fit to match measured initial hydration rates tested. The pseudo (i.e., no central complex) random Quad Quad Iso Ping Pong mechanism with one transitory complex was retained which implied a possible competitive intermolecular proton transfer step by the CO2/HCO3− pair with respect to external buffer. The model suggests this role could be emphasized in product inhibition conditions at high bicarbonate/buffer concentration ratios. A 4-parameter kinetic model was derived to complement the existing single- (intra- or intermolecular) limiting-step models for HCA II catalyzed hydration of CO2 in which were accounted for altogether the enzyme isomerization and CO2/HCO3− proton transfer via a [CO2]·[HCO3−] coupling, the CO2/HCO3− proton transfer via [HCO3−]2 and [CO2]·[HCO3−]2 couplings, and an enzyme−substrate transitory complex via [CO2]·[HCO3−]·[Buffer] coupling. This model may prove helpful for analysis of CO2 capture reactor models subject to mixed (intra- or intermolecular) proton-transfer control, intermolecular proton transfer competition by the CO2/HCO3− pair, and large CO2 conversions. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101338r [article] Kinetic model for the reversible hydration of carbon dioxide catalyzed by human carbonic anhydrase II [texte imprimé] / F. Larachi, Auteur . - 2010 . - pp. 9095–9104. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 19 (Octobre 2010) . - pp. 9095–9104 Mots-clés : Kinetic  Hydration  carbon  dioxide Résumé : Four variants of the two-step Ping Pong mechanism for the reversible hydration of carbon dioxide to bicarbonate catalyzed by free human carbonic anhydrase II (HCA II) in solutions were derived and their goodness-of-fit to match measured initial hydration rates tested. The pseudo (i.e., no central complex) random Quad Quad Iso Ping Pong mechanism with one transitory complex was retained which implied a possible competitive intermolecular proton transfer step by the CO2/HCO3− pair with respect to external buffer. The model suggests this role could be emphasized in product inhibition conditions at high bicarbonate/buffer concentration ratios. A 4-parameter kinetic model was derived to complement the existing single- (intra- or intermolecular) limiting-step models for HCA II catalyzed hydration of CO2 in which were accounted for altogether the enzyme isomerization and CO2/HCO3− proton transfer via a [CO2]·[HCO3−] coupling, the CO2/HCO3− proton transfer via [HCO3−]2 and [CO2]·[HCO3−]2 couplings, and an enzyme−substrate transitory complex via [CO2]·[HCO3−]·[Buffer] coupling. This model may prove helpful for analysis of CO2 capture reactor models subject to mixed (intra- or intermolecular) proton-transfer control, intermolecular proton transfer competition by the CO2/HCO3− pair, and large CO2 conversions. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101338r

Varying gravity force using magnetic-field emulated artificial gravity: application to cocurrent gas−liquid flows in porous media / F. Larachi in Industrial & engineering chemistry research, Vol. 49 N° 8 (Avril 2010) 

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