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Tracking catalyst activity during fluidized-bed catalytic cracking / Gladys Jiménez-García 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. 1220–1227 Titre : Tracking catalyst activity during fluidized-bed catalytic cracking Type de document : texte imprimé Auteurs : Gladys Jiménez-García, Auteur ; Ricardo Aguilar-López, Auteur ; Elizabeth León-Becerril, Auteur Année de publication : 2009 Article en page(s) : p. 1220–1227 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Chimie  industrial  Catalytic  cracking  Industrial  reactor Résumé : Fluidized-bed catalytic cracking (FCC) of vacuum gas oils, which produces aggregated value liquid fuels such as gasoline and liquid petroleum gas, is an important process in petroleum refining. Cracking reactions take place in risers, which are transported solid bed devices. In order to model risers it is necessary to develop kinetic schemes; however, complex catalyst deactivation, reaction paths, and nonisothermal behavior of these adiabatic units make it difficult to propose accurate schemes. The main mechanism of catalyst deactivation has been under research for more than 60 years, being related to coke formation during FCC reactions and the consequent active sites coverage and catalyst’s pore blockage. Although it is usual to model these phenomena as a function of “time-on-stream”, it is possible to explain it in terms of effectiveness factors. If pore blockage is noticeable, then different activity related to each reactant is reflected by the relative magnitude of individual effective diffusion coefficients; unfortunately, these transport parameters are difficult to measure. In this work, a theoretical methodology based on the comparison of yield to products from different feed stocks is proposed to track catalyst activity dynamics; estimation functions are based on fundamental transport parameters, mainly effective diffusion, inside the catalyst particle. Experimental results obtained in microactivity tests and industrial reactors are used to adjust values of catalytic activity and probe the approach proposed; simulation results for an industrial riser reactor confirm the satisfactory description of the activity profiles En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800650y [article] Tracking catalyst activity during fluidized-bed catalytic cracking [texte imprimé] / Gladys Jiménez-García, Auteur ; Ricardo Aguilar-López, Auteur ; Elizabeth León-Becerril, Auteur . - 2009 . - p. 1220–1227. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1220–1227 Mots-clés : Chimie  industrial  Catalytic  cracking  Industrial  reactor Résumé : Fluidized-bed catalytic cracking (FCC) of vacuum gas oils, which produces aggregated value liquid fuels such as gasoline and liquid petroleum gas, is an important process in petroleum refining. Cracking reactions take place in risers, which are transported solid bed devices. In order to model risers it is necessary to develop kinetic schemes; however, complex catalyst deactivation, reaction paths, and nonisothermal behavior of these adiabatic units make it difficult to propose accurate schemes. The main mechanism of catalyst deactivation has been under research for more than 60 years, being related to coke formation during FCC reactions and the consequent active sites coverage and catalyst’s pore blockage. Although it is usual to model these phenomena as a function of “time-on-stream”, it is possible to explain it in terms of effectiveness factors. If pore blockage is noticeable, then different activity related to each reactant is reflected by the relative magnitude of individual effective diffusion coefficients; unfortunately, these transport parameters are difficult to measure. In this work, a theoretical methodology based on the comparison of yield to products from different feed stocks is proposed to track catalyst activity dynamics; estimation functions are based on fundamental transport parameters, mainly effective diffusion, inside the catalyst particle. Experimental results obtained in microactivity tests and industrial reactors are used to adjust values of catalytic activity and probe the approach proposed; simulation results for an industrial riser reactor confirm the satisfactory description of the activity profiles En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800650y