Documents disponibles écrits par cet auteur

Biomass catalytic steam gasification thermodynamics analysis and reaction experiments in a CREC riser simulator / Enrique Salaices in Industrial & engineering chemistry research, Vol. 49 N° 15 (Août 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 15 (Août 2010) . - pp 6834–6844 Titre : Biomass catalytic steam gasification thermodynamics analysis and reaction experiments in a CREC riser simulator Type de document : texte imprimé Auteurs : Enrique Salaices, Auteur ; Benito Serrano, Auteur ; Hugo De Lasa, Auteur Année de publication : 2010 Article en page(s) : pp 6834–6844 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalytic  Thermodynamics  Gasification. Résumé : A thermodynamic equilibrium model based on evaluations involving C, H, and O element balances and various product species up to C6 hydrocarbons is reported in this study. This model establishes the effects of biomass composition, temperature, and steam on the various gas product molar fractions. On this basis, most significant parameters determining the chemical interconversions and distribution of chemical species are identified. On the basis of the proposed equilibrium model and using glucose as a model biomass species [C6H12O6], an optimum gasification temperature close to 800 °C and a steam/biomass ratio between 0.5 and 0.7 g/g is established. This study has the special value of comparing thermodynamic equilibrium predictions with experimental data obtained in a CREC riser simulator using a fluidizable Ni−Al2O3 catalyst. Results are relevant for scaled-up gasifiers. They show that for reaction times longer than 30 s chemical species are essentially equilibrated and that the proposed model does provide adequate description of various product fractions. Data obtained also demonstrate the shortcomings of equilibrium models for gasifiers with reaction times shorter than 10 s and the need for nonequilibrium models to describe gasifier performance at such conditions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901710n [article] Biomass catalytic steam gasification thermodynamics analysis and reaction experiments in a CREC riser simulator [texte imprimé] / Enrique Salaices, Auteur ; Benito Serrano, Auteur ; Hugo De Lasa, Auteur . - 2010 . - pp 6834–6844. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 15 (Août 2010) . - pp 6834–6844 Mots-clés : Catalytic  Thermodynamics  Gasification. Résumé : A thermodynamic equilibrium model based on evaluations involving C, H, and O element balances and various product species up to C6 hydrocarbons is reported in this study. This model establishes the effects of biomass composition, temperature, and steam on the various gas product molar fractions. On this basis, most significant parameters determining the chemical interconversions and distribution of chemical species are identified. On the basis of the proposed equilibrium model and using glucose as a model biomass species [C6H12O6], an optimum gasification temperature close to 800 °C and a steam/biomass ratio between 0.5 and 0.7 g/g is established. This study has the special value of comparing thermodynamic equilibrium predictions with experimental data obtained in a CREC riser simulator using a fluidizable Ni−Al2O3 catalyst. Results are relevant for scaled-up gasifiers. They show that for reaction times longer than 30 s chemical species are essentially equilibrated and that the proposed model does provide adequate description of various product fractions. Data obtained also demonstrate the shortcomings of equilibrium models for gasifiers with reaction times shorter than 10 s and the need for nonequilibrium models to describe gasifier performance at such conditions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901710n

Catalytic conversion of thiophene under mild conditions over a ZSM-5 catalyst / Lisette Jaimes in Industrial & engineering chemistry research, Vol. 48 N° 16 (Août 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7505–7516 Titre : Catalytic conversion of thiophene under mild conditions over a ZSM-5 catalyst : a kinetic model Type de document : texte imprimé Auteurs : Lisette Jaimes, Auteur ; Hugo De Lasa, Auteur Année de publication : 2009 Article en page(s) : pp. 7505–7516 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : FCC  gasoline  processes  H-ZSM-5  zeolite  Thiophene Résumé : Currently, refiners consider the post-treatment of FCC gasoline processes to be a viable and likely less costly path for meeting environmental regulations on sulfur. Several promising catalytic desulfurization post-treatment processes do not require hydrogen addition and use zeolites. This type of desulfurization leads to significant levels of coke, and as a result, it is being considered for implementation in twin fluid beds (reactor and regenerator) to maintain the catalyst activity. This study evaluates the conversion of thiophene on H-ZSM-5 zeolite in a silica matrix. Experiments were carried out in the CREC fluidized riser simulator under mild conditions using thiophene/n-octane and thiophene/1-octene mixtures. The results show a high and selective thiophene conversion. It is speculated that thiophene conversion takes place via ring opening and alkylation to form H2S, aromatics, alkylthiophenes, benzothiophene, and coke. These observations are in agreement with previous thermodynamic analyses. On this basis, a reaction network and kinetic model are proposed. Numerical regression leads to kinetic parameters with narrow spans, suggesting that the proposed model satisfactorily simulate thiophene removal under the suggested gasoline post-treatment conditions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8020126 [article] Catalytic conversion of thiophene under mild conditions over a ZSM-5 catalyst : a kinetic model [texte imprimé] / Lisette Jaimes, Auteur ; Hugo De Lasa, Auteur . - 2009 . - pp. 7505–7516. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7505–7516 Mots-clés : FCC  gasoline  processes  H-ZSM-5  zeolite  Thiophene Résumé : Currently, refiners consider the post-treatment of FCC gasoline processes to be a viable and likely less costly path for meeting environmental regulations on sulfur. Several promising catalytic desulfurization post-treatment processes do not require hydrogen addition and use zeolites. This type of desulfurization leads to significant levels of coke, and as a result, it is being considered for implementation in twin fluid beds (reactor and regenerator) to maintain the catalyst activity. This study evaluates the conversion of thiophene on H-ZSM-5 zeolite in a silica matrix. Experiments were carried out in the CREC fluidized riser simulator under mild conditions using thiophene/n-octane and thiophene/1-octene mixtures. The results show a high and selective thiophene conversion. It is speculated that thiophene conversion takes place via ring opening and alkylation to form H2S, aromatics, alkylthiophenes, benzothiophene, and coke. These observations are in agreement with previous thermodynamic analyses. On this basis, a reaction network and kinetic model are proposed. Numerical regression leads to kinetic parameters with narrow spans, suggesting that the proposed model satisfactorily simulate thiophene removal under the suggested gasoline post-treatment conditions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8020126

Energy efficiencies in a photo - CREC - air reactor / Juan Manuel Garcia-Hernandez in Industrial & engineering chemistry research, Vol. 51 N° 16 (Avril 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 16 (Avril 2012) . - pp. 5715-5727 Titre : Energy efficiencies in a photo - CREC - air reactor : Conversion of model organic pollutants in air Type de document : texte imprimé Auteurs : Juan Manuel Garcia-Hernandez, Auteur ; Benito Serrano-Rosales, Auteur ; Hugo De Lasa, Auteur Année de publication : 2012 Article en page(s) : pp. 5715-5727 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Pollutant  Modeling  Reactor  Energetic  efficiency Résumé : The energy efficiency of the photocatalytic conversion of gas-phase organic pollutants was studied using a redesigned and scaled-up photo-CREC-air reactor. This photocatalytic unit has the unique feature of allowing an accurate analysis of the irradiation field by establishing macroscopic balances and in situ measurements. The photo-CREC-air reactor operates in batch mode with the photocatalyst supported by a stainless steel mesh being irradiated by eight UV lamps. Kinetic modeling was performed, and quantum yields (QYs) and photochemical thermodynamic efficiency factors (PTEFs) were calculated using data for acetone and acetaldehyde photocatalytic degradation in ambient air utilizing a Degussa P25 (Aeroxide 25) photocatalyst. It was found that the photo-CREC-air reactor is suitable for the determination of kinetic and adsorption parameters, given a design with excellent irradiation usage and fluid-catalyst contact. In this respect, quantum yields for both acetone and acetaldehyde exceed the value of 1 (equivalent to 100%), with PTEFs in both cases remaining below the level of 1, as required by thermodynamics. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25834485 [article] Energy efficiencies in a photo - CREC - air reactor : Conversion of model organic pollutants in air [texte imprimé] / Juan Manuel Garcia-Hernandez, Auteur ; Benito Serrano-Rosales, Auteur ; Hugo De Lasa, Auteur . - 2012 . - pp. 5715-5727. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 16 (Avril 2012) . - pp. 5715-5727 Mots-clés : Pollutant  Modeling  Reactor  Energetic  efficiency Résumé : The energy efficiency of the photocatalytic conversion of gas-phase organic pollutants was studied using a redesigned and scaled-up photo-CREC-air reactor. This photocatalytic unit has the unique feature of allowing an accurate analysis of the irradiation field by establishing macroscopic balances and in situ measurements. The photo-CREC-air reactor operates in batch mode with the photocatalyst supported by a stainless steel mesh being irradiated by eight UV lamps. Kinetic modeling was performed, and quantum yields (QYs) and photochemical thermodynamic efficiency factors (PTEFs) were calculated using data for acetone and acetaldehyde photocatalytic degradation in ambient air utilizing a Degussa P25 (Aeroxide 25) photocatalyst. It was found that the photo-CREC-air reactor is suitable for the determination of kinetic and adsorption parameters, given a design with excellent irradiation usage and fluid-catalyst contact. In this respect, quantum yields for both acetone and acetaldehyde exceed the value of 1 (equivalent to 100%), with PTEFs in both cases remaining below the level of 1, as required by thermodynamics. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25834485

Heterogeneous approach to the catalytic cracking of vacuum gas oil / Mustafa Al-Sabawi in Industrial & engineering chemistry research, Vol. 47 N°20 (Octobre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7631-7641 Titre : Heterogeneous approach to the catalytic cracking of vacuum gas oil Type de document : texte imprimé Auteurs : Mustafa Al-Sabawi, Editeur scientifique ; Jesús A. Atias, Editeur scientifique ; Hugo De Lasa, Editeur scientifique Année de publication : 2008 Article en page(s) : P. 7631-7641 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Gas  Oil  Zeolite  catalysts Résumé : This study examines the roles of intracrystallite diffusion and reaction phenomena during the catalytic cracking of vacuum gas oil. Catalytic cracking experiments on FCC-type catalysts were performed in a fluidized bench-scale CREC riser simulator. This reactor was operated under close-to-industrial FCC conditions in terms of temperature, reaction time, partial pressures of reactant and products, and catalyst-to-oil ratio. The activity and selectivity of two USY zeolite catalysts, with very similar properties but varying zeolite crystallite sizes, were determined. A five-lump kinetic model describing the catalytic cracking of gas oil to light cycle oil, gasoline, light gases, and coke and accounting for diffusional constraints experienced by hydrocarbons while evolving in the zeolite pore network was considered. The results show that the catalyst with the smaller crystallites provided higher activity and selectivity toward desirable intermediate products (gasoline with low aromatics) and lower selectivity for terminal products (coke), indicating that diffusion plays a significant role in catalytic cracking. Diffusivity and kinetic parameters, including modified Thiele modulus and effectiveness factor, were established to determine the effects of crystallite size and temperature on the operating regime of the catalyst. It was found that, in the 510−530 °C range, the overall cracking rate is controlled by the highly temperature-sensitive intracrystalline gas oil transport, whereas in the 550−570 °C range, the overall cracking rate is dominated by a mildly temperature-sensitive intrinsic cracking rate. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701745k [article] Heterogeneous approach to the catalytic cracking of vacuum gas oil [texte imprimé] / Mustafa Al-Sabawi, Editeur scientifique ; Jesús A. Atias, Editeur scientifique ; Hugo De Lasa, Editeur scientifique . - 2008 . - P. 7631-7641. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7631-7641 Mots-clés : Gas  Oil  Zeolite  catalysts Résumé : This study examines the roles of intracrystallite diffusion and reaction phenomena during the catalytic cracking of vacuum gas oil. Catalytic cracking experiments on FCC-type catalysts were performed in a fluidized bench-scale CREC riser simulator. This reactor was operated under close-to-industrial FCC conditions in terms of temperature, reaction time, partial pressures of reactant and products, and catalyst-to-oil ratio. The activity and selectivity of two USY zeolite catalysts, with very similar properties but varying zeolite crystallite sizes, were determined. A five-lump kinetic model describing the catalytic cracking of gas oil to light cycle oil, gasoline, light gases, and coke and accounting for diffusional constraints experienced by hydrocarbons while evolving in the zeolite pore network was considered. The results show that the catalyst with the smaller crystallites provided higher activity and selectivity toward desirable intermediate products (gasoline with low aromatics) and lower selectivity for terminal products (coke), indicating that diffusion plays a significant role in catalytic cracking. Diffusivity and kinetic parameters, including modified Thiele modulus and effectiveness factor, were established to determine the effects of crystallite size and temperature on the operating regime of the catalyst. It was found that, in the 510−530 °C range, the overall cracking rate is controlled by the highly temperature-sensitive intracrystalline gas oil transport, whereas in the 550−570 °C range, the overall cracking rate is dominated by a mildly temperature-sensitive intrinsic cracking rate. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701745k