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Kinetic Model for the Transformation of Bioethanol into Olefins over a HZSM-5 Zeolite Treated with Alkali / Ana G. Gayubo 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. 10836–10844 Titre : Kinetic Model for the Transformation of Bioethanol into Olefins over a HZSM-5 Zeolite Treated with Alkali Type de document : texte imprimé Auteurs : Ana G. Gayubo, Auteur ; Ainhoa Alonso, Auteur ; Beatriz Valle, Auteur Année de publication : 2011 Article en page(s) : pp. 10836–10844 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetic  Bioethanol  Zeolite Résumé : A kinetic model for the transformation of bioethanol (aqueous ethanol into hydrocarbons) has been established for a catalyst with slow deactivation by coke (prepared from a HZSM-5 zeolite treated with alkali in order to moderate its acid strength and generate mesopores in the zeolite structure). The kinetic model allows quantifying the distribution of the lumps of products (ethylene, C3−C4 olefins, gasoline or C5−C10, and C1−C3 paraffins) and is particularly interesting for quantifying the production of C3−C4 olefin lump, which is the one of greater commercial interest. The experimental data have been obtained in an isothermal fixed-bed reactor in a wide range of operating conditions (temperature of 300−400 °C, space time and water content in the feed). The remarkable features of the kinetic model are (i) consideration of the autocatalytic formation of C3−C4 olefin lump following their reaction with ethylene, (ii) consideration of the combined involvement of ethylene and the light olefin lump in the formation of heavier hydrocarbons; and (i) quantification of the effect of water in the reaction medium, which attenuates the rate of each one of the steps in the kinetic scheme, except the dehydration of ethanol which is instantaneous under these conditions. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100407d [article] Kinetic Model for the Transformation of Bioethanol into Olefins over a HZSM-5 Zeolite Treated with Alkali [texte imprimé] / Ana G. Gayubo, Auteur ; Ainhoa Alonso, Auteur ; Beatriz Valle, Auteur . - 2011 . - pp. 10836–10844. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10836–10844 Mots-clés : Kinetic  Bioethanol  Zeolite Résumé : A kinetic model for the transformation of bioethanol (aqueous ethanol into hydrocarbons) has been established for a catalyst with slow deactivation by coke (prepared from a HZSM-5 zeolite treated with alkali in order to moderate its acid strength and generate mesopores in the zeolite structure). The kinetic model allows quantifying the distribution of the lumps of products (ethylene, C3−C4 olefins, gasoline or C5−C10, and C1−C3 paraffins) and is particularly interesting for quantifying the production of C3−C4 olefin lump, which is the one of greater commercial interest. The experimental data have been obtained in an isothermal fixed-bed reactor in a wide range of operating conditions (temperature of 300−400 °C, space time and water content in the feed). The remarkable features of the kinetic model are (i) consideration of the autocatalytic formation of C3−C4 olefin lump following their reaction with ethylene, (ii) consideration of the combined involvement of ethylene and the light olefin lump in the formation of heavier hydrocarbons; and (i) quantification of the effect of water in the reaction medium, which attenuates the rate of each one of the steps in the kinetic scheme, except the dehydration of ethanol which is instantaneous under these conditions. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100407d

Olefin production by catalytic transformation of crude bio-oil in a two-step process / Ana G. Gayubo in Industrial & engineering chemistry research, Vol. 49 N° 1 (Janvier 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 1 (Janvier 2010) . - pp. 123–131 Titre : Olefin production by catalytic transformation of crude bio-oil in a two-step process Type de document : texte imprimé Auteurs : Ana G. Gayubo, Auteur ; Beatriz Valle, Auteur ; Andrés T. Aguayo, Auteur Année de publication : 2010 Article en page(s) : pp. 123–131 Note générale : Industrail chemistry Langues : Anglais (eng) Mots-clés : Olefin--Production--Catalytic--Transformation--Crude--Bio-Oil----Two-Step  Process Résumé : The valorization of crude bio-oil by catalytic transformation into hydrocarbons has been carried out in an online two-step (thermal-catalytic) process. The deposition of pyrolytic lignin, formed by polymerization of biomass-derived products, is enhanced in the thermal step. Volatiles are processed in a fluidized bed reactor with a catalyst that is hydrothermally stable and selective for olefin production, which has been based on a HZSM-5 zeolite. A study has been made of the effect of operating conditions (methanol content in the feed of bio-oil/methanol, temperature, space time, and time on stream) on bio-oil conversion, product lump yields and the selectivity of each individual C2−C4 olefin. These conditions also have a significant effect on deactivation, which is attributed to coke deposited on the catalyst. The TPO curves of coke combustion identify two fractions: one of thermal origin (pyrolytic lignin) and the other of catalytic origin, whose formation depends on the concentration of oxygenates in the reaction medium. A feed with 50 wt % of methanol, at 500 °C, with space time of 0.371 (g of catalyst) h (g of methanol)−1 allows a 94 wt % conversion of the bio-oil in the feed, with a selectivity of C2−C4 olefins of 48 wt % (50 wt % is propene) and low yields of CO and CO2 (its formation is attenuated by cofeeding methanol). ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901204n [article] Olefin production by catalytic transformation of crude bio-oil in a two-step process [texte imprimé] / Ana G. Gayubo, Auteur ; Beatriz Valle, Auteur ; Andrés T. Aguayo, Auteur . - 2010 . - pp. 123–131. Industrail chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 1 (Janvier 2010) . - pp. 123–131 Mots-clés : Olefin--Production--Catalytic--Transformation--Crude--Bio-Oil----Two-Step  Process Résumé : The valorization of crude bio-oil by catalytic transformation into hydrocarbons has been carried out in an online two-step (thermal-catalytic) process. The deposition of pyrolytic lignin, formed by polymerization of biomass-derived products, is enhanced in the thermal step. Volatiles are processed in a fluidized bed reactor with a catalyst that is hydrothermally stable and selective for olefin production, which has been based on a HZSM-5 zeolite. A study has been made of the effect of operating conditions (methanol content in the feed of bio-oil/methanol, temperature, space time, and time on stream) on bio-oil conversion, product lump yields and the selectivity of each individual C2−C4 olefin. These conditions also have a significant effect on deactivation, which is attributed to coke deposited on the catalyst. The TPO curves of coke combustion identify two fractions: one of thermal origin (pyrolytic lignin) and the other of catalytic origin, whose formation depends on the concentration of oxygenates in the reaction medium. A feed with 50 wt % of methanol, at 500 °C, with space time of 0.371 (g of catalyst) h (g of methanol)−1 allows a 94 wt % conversion of the bio-oil in the feed, with a selectivity of C2−C4 olefins of 48 wt % (50 wt % is propene) and low yields of CO and CO2 (its formation is attenuated by cofeeding methanol). ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901204n