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Mechanistic modeling of cobalt based catalyst sintering in a fixed bed reactor under different conditions of fischer – tropsch synthesis / Majid Sadeqzadeh 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. 11955–11964 Titre : Mechanistic modeling of cobalt based catalyst sintering in a fixed bed reactor under different conditions of fischer – tropsch synthesis Type de document : texte imprimé Auteurs : Majid Sadeqzadeh, Auteur ; Jingping Hong, Auteur ; Pascal Fongarland, Auteur Année de publication : 2012 Article en page(s) : pp. 11955–11964 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Catalyst Résumé : A three-step sintering mechanism is proposed for Co-based catalysts under Fischer–Tropsch reaction conditions. This mechanism includes an intermediate formation of oxide layer on cobalt metal nanoparticles in the presence of water. The partially reversibly oxidized surface accelerates sintering by both reducing the surface energy and enhancing the diffusion rates of cobalt particles. The proposed mechanism is then employed for a fixed-bed unsteady state reactor. The effect of particle growth on the catalytic activity was analyzed within a diverse range of operating conditions (syngas ratio = 1.5–4, water co-feed ratio = 0–6, inert co-feed ratio = 0–6). It is found that, at the same gas space velocity, sintering proceeds faster at higher H2/CO ratios. At the same initial conversion, a low H2/CO syngas ratio increases sintering severity, i.e., catalyst deactivation due to the crystallite growth, as it brings about higher relative water partial pressure. Dilution of syngas with different amounts of inert gas does not affect the cobalt sintering rate. Cobalt sintering proceeds more rapidly if water is co-fed during the reaction. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3006929 [article] Mechanistic modeling of cobalt based catalyst sintering in a fixed bed reactor under different conditions of fischer – tropsch synthesis [texte imprimé] / Majid Sadeqzadeh, Auteur ; Jingping Hong, Auteur ; Pascal Fongarland, Auteur . - 2012 . - pp. 11955–11964. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 37 (Septembre 2012) . - pp. 11955–11964 Mots-clés : Catalyst Résumé : A three-step sintering mechanism is proposed for Co-based catalysts under Fischer–Tropsch reaction conditions. This mechanism includes an intermediate formation of oxide layer on cobalt metal nanoparticles in the presence of water. The partially reversibly oxidized surface accelerates sintering by both reducing the surface energy and enhancing the diffusion rates of cobalt particles. The proposed mechanism is then employed for a fixed-bed unsteady state reactor. The effect of particle growth on the catalytic activity was analyzed within a diverse range of operating conditions (syngas ratio = 1.5–4, water co-feed ratio = 0–6, inert co-feed ratio = 0–6). It is found that, at the same gas space velocity, sintering proceeds faster at higher H2/CO ratios. At the same initial conversion, a low H2/CO syngas ratio increases sintering severity, i.e., catalyst deactivation due to the crystallite growth, as it brings about higher relative water partial pressure. Dilution of syngas with different amounts of inert gas does not affect the cobalt sintering rate. Cobalt sintering proceeds more rapidly if water is co-fed during the reaction. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3006929