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Influences of water and syngas partial pressure on the kinetics of a commercial alumina-supported cobalt Fischer-Tropsch catalyst / F. Gideon Botes in Industrial & engineering chemistry research, Vol. 48 N°4 (Février 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1859–1865 Titre : Influences of water and syngas partial pressure on the kinetics of a commercial alumina-supported cobalt Fischer-Tropsch catalyst Type de document : texte imprimé Auteurs : F. Gideon Botes, Auteur Année de publication : 2009 Article en page(s) : pp. 1859–1865 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Alumina-supported  cobalt  Fischer-Tropsch  catalyst  Water  partial  pressure  Syngas  pressure Résumé : The influences of the water partial pressure and the syngas pressure on the reaction kinetics of a commercial alumina-supported cobalt Fischer−Tropsch (FT) catalyst were investigated. Both a fresh catalyst, as well as an aged catalyst from a demonstration reactor, were employed in the study. It was concluded that water has a negligible influence on the overall FT reaction rate but lowers the methane selectivity and increases the CO2 selectivity. Longer term exposure to higher water partial pressures did not lead to step changes in the catalyst activity but may have increased the rate of gradual irreversible catalyst deactivation. Increasing the syngas pressure at constant H2/CO ratio significantly increased the FT reaction rate and decreased the methane selectivity, suggesting a substantial incentive to explore higher pressure operation of commercial cobalt−FT processes. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8013023 [article] Influences of water and syngas partial pressure on the kinetics of a commercial alumina-supported cobalt Fischer-Tropsch catalyst [texte imprimé] / F. Gideon Botes, Auteur . - 2009 . - pp. 1859–1865. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1859–1865 Mots-clés : Alumina-supported  cobalt  Fischer-Tropsch  catalyst  Water  partial  pressure  Syngas  pressure Résumé : The influences of the water partial pressure and the syngas pressure on the reaction kinetics of a commercial alumina-supported cobalt Fischer−Tropsch (FT) catalyst were investigated. Both a fresh catalyst, as well as an aged catalyst from a demonstration reactor, were employed in the study. It was concluded that water has a negligible influence on the overall FT reaction rate but lowers the methane selectivity and increases the CO2 selectivity. Longer term exposure to higher water partial pressures did not lead to step changes in the catalyst activity but may have increased the rate of gradual irreversible catalyst deactivation. Increasing the syngas pressure at constant H2/CO ratio significantly increased the FT reaction rate and decreased the methane selectivity, suggesting a substantial incentive to explore higher pressure operation of commercial cobalt−FT processes. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8013023

The development of a macro kinetic model for a commercial Co/Pt/Al2O3 fischer−tropsch catalyst / F. Gideon Botes in Industrial & engineering chemistry research, Vol. 48 N° 23 (Décembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 23 (Décembre 2009) . - pp. 10439–10447 Titre : The development of a macro kinetic model for a commercial Co/Pt/Al2O3 fischer−tropsch catalyst Type de document : texte imprimé Auteurs : F. Gideon Botes, Auteur ; Braam van Dyk, Auteur ; Craig McGregor, Auteur Année de publication : 2010 Article en page(s) : pp. 10439–10447 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Development--Macro--Kinetic--Model--Commercial--Co/Pt/Al2O3--Fischer−Tropsch--Catalyst Résumé : An experimental study was performed with an aged Co/Pt/Al2O3 catalyst in a laboratory slurry reactor to develop a macrokinetic expression for the Fischer−Tropsch (FT) synthesis. A semiempirical model was found to be the preferred two-parameter rate equation of the reaction. However, it was shown that this model is virtually indistinguishable from a mechanistically derived three-parameter rate model that assumes the following kinetically relevant steps in the cobalt-FT synthesis: CO dissociation occurs without hydrogen interaction and is not a rate-limiting step; the first hydrogen addition to surface carbon and the second hydrogen addition to surface oxygen are the rate-determining steps. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900119z [article] The development of a macro kinetic model for a commercial Co/Pt/Al2O3 fischer−tropsch catalyst [texte imprimé] / F. Gideon Botes, Auteur ; Braam van Dyk, Auteur ; Craig McGregor, Auteur . - 2010 . - pp. 10439–10447. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 23 (Décembre 2009) . - pp. 10439–10447 Mots-clés : Development--Macro--Kinetic--Model--Commercial--Co/Pt/Al2O3--Fischer−Tropsch--Catalyst Résumé : An experimental study was performed with an aged Co/Pt/Al2O3 catalyst in a laboratory slurry reactor to develop a macrokinetic expression for the Fischer−Tropsch (FT) synthesis. A semiempirical model was found to be the preferred two-parameter rate equation of the reaction. However, it was shown that this model is virtually indistinguishable from a mechanistically derived three-parameter rate model that assumes the following kinetically relevant steps in the cobalt-FT synthesis: CO dissociation occurs without hydrogen interaction and is not a rate-limiting step; the first hydrogen addition to surface carbon and the second hydrogen addition to surface oxygen are the rate-determining steps. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900119z