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A new way to look at fischer−tropsch synthesis using flushing axperiments / Xiaojun Lu in Industrial & engineering chemistry research, Vol. 50 N° 8 (Avril 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4359–4365 Titre : A new way to look at fischer−tropsch synthesis using flushing axperiments Type de document : texte imprimé Auteurs : Xiaojun Lu, Auteur ; Xiaowei Zhu, Auteur ; Diane Hildebrandt, Auteur Année de publication : 2011 Article en page(s) : pp. 4359–4365 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Fischer  tropsch  synthesis Résumé : When Fischer−Tropsch synthesis (FTS) reaction experiments were conducted in a gas−solid system with a TiO2-supported cobalt catalyst in a continuous stirred tank reactor (CSTR), we observed significant changes in the reaction rate and product selectivity at an early stage of time on stream (TOS) when all the reaction conditions were kept constant.(1) We designed flushing experiments with an inert gas that started when the FTS reaction had reached steady state. After the completion of flushing, the FTS reaction was resumed with syngas. We then compared the results of the FTS reaction rate and product selectivity both before and after flushing. The flushing experimental results suggested that the marked variations we observed were caused (either wholly or mainly) by liquid products deposited in the catalyst rather than by the change in the properties of the catalyst surface. The concentrations and the relative amount of the reactant in the flushed out stream were examined and the implications of the high H2/CO ratio for the reaction kinetics and product selectivity are discussed. On the basis of the dynamic concentrations of C1−C8 in the flushed outgas, we propose that reaction among the products takes place under moderate FTS reaction conditions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102095c [article] A new way to look at fischer−tropsch synthesis using flushing axperiments [texte imprimé] / Xiaojun Lu, Auteur ; Xiaowei Zhu, Auteur ; Diane Hildebrandt, Auteur . - 2011 . - pp. 4359–4365. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4359–4365 Mots-clés : Fischer  tropsch  synthesis Résumé : When Fischer−Tropsch synthesis (FTS) reaction experiments were conducted in a gas−solid system with a TiO2-supported cobalt catalyst in a continuous stirred tank reactor (CSTR), we observed significant changes in the reaction rate and product selectivity at an early stage of time on stream (TOS) when all the reaction conditions were kept constant.(1) We designed flushing experiments with an inert gas that started when the FTS reaction had reached steady state. After the completion of flushing, the FTS reaction was resumed with syngas. We then compared the results of the FTS reaction rate and product selectivity both before and after flushing. The flushing experimental results suggested that the marked variations we observed were caused (either wholly or mainly) by liquid products deposited in the catalyst rather than by the change in the properties of the catalyst surface. The concentrations and the relative amount of the reactant in the flushed out stream were examined and the implications of the high H2/CO ratio for the reaction kinetics and product selectivity are discussed. On the basis of the dynamic concentrations of C1−C8 in the flushed outgas, we propose that reaction among the products takes place under moderate FTS reaction conditions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102095c

Study of radial heat transfer in a tubular fischer - tropsch synthesis reactor / Xiaowei Zhu in Industrial & engineering chemistry research, Vol. 49 N° 21 (Novembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10682-10688 Titre : Study of radial heat transfer in a tubular fischer - tropsch synthesis reactor Type de document : texte imprimé Auteurs : Xiaowei Zhu, Auteur ; Xiaojun Lu, Auteur ; Xinying Liu, Auteur Année de publication : 2011 Article en page(s) : pp. 10682-10688 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Reactor  Fischer  Tropsch  synthesis  Heat  transfer Résumé : A series of experiments were performed to investigate and compare the heat transfer characteristics of a catalyst bed during the Fischer-Tropsch synthesis (FTS) reaction and heating without the reaction. A Co/ TiO2 catalyst was used in a relatively large internal diameter (ID) tubular reactor. In the first set of experiments, the bed was run under typical low-temperature FTS conditions, while in the second set an inert gas was fed to the bed and a heater with variable heat output was used along the center axis of the catalytic bed to generate the temperature profile. The two-dimensional (radial and axial) temperature profiles in the bed in both cases were measured for varying flow rates and reactor wall temperatures. Simple radial heat transfer models were derived for these two sets of experiments, and the effective thermal conductivity coefficients of the catalyst bed were estimated. Comparisons of the results showed that there were considerable differences between the values of the coefficients and in the shape of the temperature profiles in the reaction and nonreaction cases. This suggests that the liquid formed during the reaction may play an important role in affecting the heat transfer characteristics of the catalyst bed. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23447961 [article] Study of radial heat transfer in a tubular fischer - tropsch synthesis reactor [texte imprimé] / Xiaowei Zhu, Auteur ; Xiaojun Lu, Auteur ; Xinying Liu, Auteur . - 2011 . - pp. 10682-10688. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10682-10688 Mots-clés : Reactor  Fischer  Tropsch  synthesis  Heat  transfer Résumé : A series of experiments were performed to investigate and compare the heat transfer characteristics of a catalyst bed during the Fischer-Tropsch synthesis (FTS) reaction and heating without the reaction. A Co/ TiO2 catalyst was used in a relatively large internal diameter (ID) tubular reactor. In the first set of experiments, the bed was run under typical low-temperature FTS conditions, while in the second set an inert gas was fed to the bed and a heater with variable heat output was used along the center axis of the catalytic bed to generate the temperature profile. The two-dimensional (radial and axial) temperature profiles in the bed in both cases were measured for varying flow rates and reactor wall temperatures. Simple radial heat transfer models were derived for these two sets of experiments, and the effective thermal conductivity coefficients of the catalyst bed were estimated. Comparisons of the results showed that there were considerable differences between the values of the coefficients and in the shape of the temperature profiles in the reaction and nonreaction cases. This suggests that the liquid formed during the reaction may play an important role in affecting the heat transfer characteristics of the catalyst bed. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23447961