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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