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Characterization and hydrogenation activity of Ni/Si(Al)- MCM-41 catalysts prepared by deposition-precipitation / Rubén Nares in Industrial & engineering chemistry research, Vol. 48 N°3 (Février 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1154–1162 Titre : Characterization and hydrogenation activity of Ni/Si(Al)- MCM-41 catalysts prepared by deposition-precipitation Type de document : texte imprimé Auteurs : Rubén Nares, Auteur ; Jorge Ramírez, Auteur ; Aída Gutiérrez-Alejandre, Auteur ; Rogelio Cuevas, Auteur Année de publication : 2009 Article en page(s) : p. 1154–1162 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Nickel  Nickel  phyllosilicate  Catalysts  spectroscopy Résumé : The deposition−precipitation (DP) method was used for the preparation of Ni/SiMCM-41 and Ni/AlMCM-41 catalysts with different DP times (1−4 h), and the catalysts were characterized by BET, XRD, TPR, FTIR spectroscopy, and TEM. On both types of catalysts, the Ni(II) phases formed are a mixture of 1:1 nickel phyllosilicate and Ni(OH)2. The quantity of each phase at the end of the deposition process determines the final Ni particle size; i.e., greater amounts of Ni(OH)2 lead to larger Ni particles. In addition, it was found that the presence of aluminum in the framework of MCM-41 delays the formation of the nickel hydrosilicate phase. As a result of the consumption of the siliceous pore walls during DP, the long-range order of the MCM-41 hexagonal pore structure is gradually lost. Catalytic activity in the hydrogenation of naphthalene was higher for Ni/SiMCM-41 catalysts and was a linear function of the exposed area of Ni particles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800569j [article] Characterization and hydrogenation activity of Ni/Si(Al)- MCM-41 catalysts prepared by deposition-precipitation [texte imprimé] / Rubén Nares, Auteur ; Jorge Ramírez, Auteur ; Aída Gutiérrez-Alejandre, Auteur ; Rogelio Cuevas, Auteur . - 2009 . - p. 1154–1162. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1154–1162 Mots-clés : Nickel  Nickel  phyllosilicate  Catalysts  spectroscopy Résumé : The deposition−precipitation (DP) method was used for the preparation of Ni/SiMCM-41 and Ni/AlMCM-41 catalysts with different DP times (1−4 h), and the catalysts were characterized by BET, XRD, TPR, FTIR spectroscopy, and TEM. On both types of catalysts, the Ni(II) phases formed are a mixture of 1:1 nickel phyllosilicate and Ni(OH)2. The quantity of each phase at the end of the deposition process determines the final Ni particle size; i.e., greater amounts of Ni(OH)2 lead to larger Ni particles. In addition, it was found that the presence of aluminum in the framework of MCM-41 delays the formation of the nickel hydrosilicate phase. As a result of the consumption of the siliceous pore walls during DP, the long-range order of the MCM-41 hexagonal pore structure is gradually lost. Catalytic activity in the hydrogenation of naphthalene was higher for Ni/SiMCM-41 catalysts and was a linear function of the exposed area of Ni particles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800569j

Kinetic study of the HDS of 4,6-DMDBT over NiMo/Al2O3-SiO2(x) catalysts / Felipe Sánchez-Minero in Industrial & engineering chemistry research, Vol. 48 N°3 (Février 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1178–1185 Titre : Kinetic study of the HDS of 4,6-DMDBT over NiMo/Al2O3-SiO2(x) catalysts Type de document : texte imprimé Auteurs : Felipe Sánchez-Minero, Auteur ; Jorge Ramírez, Auteur ; Rogelio Cuevas-Garcia, Auteur ; Aída Gutiérrez-Alejandre, Auteur Année de publication : 2009 Article en page(s) : p. 1178–1185 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Kinetic  study  NiMo  catalyst Résumé : Two NiMo/Al2O3-SiO2(x) catalysts with different SiO2 content in the support (0 and 10 wt %) were evaluated at four temperatures (560, 573, 585, and 598 K) in the HDS of 4,6-DMDBT. The reaction products (DMDP, MCHT, and DMDCH) were analyzed to establish a reaction scheme. Then, a kinetic study using Langmuir−Hinshelwood (LH) type equations was carried out to estimate the changes in the rate constants for the direct desulfurization and hydrogenation reaction routes involved in the HDS of 4,6-DMDBT. The results show that incorporation of SiO2 to the catalyst support increases the HDS of 4,6-DMDBT and that this increase is mainly due to a greater contribution of the hydrogenation reaction. The apparent activation energy and pre-exponential factor estimated for both reaction routes indicated an increase in the number of active sites related to the hydrogenation route when SiO2 is present in the catalyst. This result was corroborated by means of NO adsorption. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8005808 [article] Kinetic study of the HDS of 4,6-DMDBT over NiMo/Al2O3-SiO2(x) catalysts [texte imprimé] / Felipe Sánchez-Minero, Auteur ; Jorge Ramírez, Auteur ; Rogelio Cuevas-Garcia, Auteur ; Aída Gutiérrez-Alejandre, Auteur . - 2009 . - p. 1178–1185. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1178–1185 Mots-clés : Kinetic  study  NiMo  catalyst Résumé : Two NiMo/Al2O3-SiO2(x) catalysts with different SiO2 content in the support (0 and 10 wt %) were evaluated at four temperatures (560, 573, 585, and 598 K) in the HDS of 4,6-DMDBT. The reaction products (DMDP, MCHT, and DMDCH) were analyzed to establish a reaction scheme. Then, a kinetic study using Langmuir−Hinshelwood (LH) type equations was carried out to estimate the changes in the rate constants for the direct desulfurization and hydrogenation reaction routes involved in the HDS of 4,6-DMDBT. The results show that incorporation of SiO2 to the catalyst support increases the HDS of 4,6-DMDBT and that this increase is mainly due to a greater contribution of the hydrogenation reaction. The apparent activation energy and pre-exponential factor estimated for both reaction routes indicated an increase in the number of active sites related to the hydrogenation route when SiO2 is present in the catalyst. This result was corroborated by means of NO adsorption. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8005808

Modeling ideal and nonideal hydrocracking of paraffins using the single-event lumped parameter hybrid (SELPH) model / Juan C. Chavarría-Hernández in Industrial & engineering chemistry research, Vol. 48 N°3 (Février 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1203–1207 Titre : Modeling ideal and nonideal hydrocracking of paraffins using the single-event lumped parameter hybrid (SELPH) model Type de document : texte imprimé Auteurs : Juan C. Chavarría-Hernández, Auteur ; Jorge Ramírez, Auteur Année de publication : 2009 Article en page(s) : p. 1203–1207 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hydrocracking  Oil  industrial  SELPH  model  kinetic Résumé : The SELPH (single-event lumped parameter hybrid) model previously developed was used to simulate hydroconversion of n-octane and n-undecane over a wide range of operating conditions, in order to cover both ideal and nonideal hydrocracking behavior. The fundamental kinetic parameters used in the simulations were estimated previously from n-octane hydroconversion experimental data. Results of simulations demonstrate that predictions of the model for the effect of (i) operating pressure, (ii) reaction temperature, (iii) chain length of feed hydrocarbon, and (iv) hydrogen-to-hydrocarbon inlet molar ratio on the ideal (and nonideal) character of hydrocracking are in complete agreement with the general trends reported in the literature. The model allowed identification of intervals of the operating variables in which product selectivities are a unique function of total conversion, i.e., an ideal hydrocracking region, while, in the region of nonideal hydrocracking, the model accurately describes the changes of product selectivities as a function of operating conditions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800639n [article] Modeling ideal and nonideal hydrocracking of paraffins using the single-event lumped parameter hybrid (SELPH) model [texte imprimé] / Juan C. Chavarría-Hernández, Auteur ; Jorge Ramírez, Auteur . - 2009 . - p. 1203–1207. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1203–1207 Mots-clés : Hydrocracking  Oil  industrial  SELPH  model  kinetic Résumé : The SELPH (single-event lumped parameter hybrid) model previously developed was used to simulate hydroconversion of n-octane and n-undecane over a wide range of operating conditions, in order to cover both ideal and nonideal hydrocracking behavior. The fundamental kinetic parameters used in the simulations were estimated previously from n-octane hydroconversion experimental data. Results of simulations demonstrate that predictions of the model for the effect of (i) operating pressure, (ii) reaction temperature, (iii) chain length of feed hydrocarbon, and (iv) hydrogen-to-hydrocarbon inlet molar ratio on the ideal (and nonideal) character of hydrocracking are in complete agreement with the general trends reported in the literature. The model allowed identification of intervals of the operating variables in which product selectivities are a unique function of total conversion, i.e., an ideal hydrocracking region, while, in the region of nonideal hydrocracking, the model accurately describes the changes of product selectivities as a function of operating conditions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800639n