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Study on void behavior in a turbulent fluidized bed with catalyst powders / Xiaoping Zhang 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 6862–6869 Titre : Study on void behavior in a turbulent fluidized bed with catalyst powders Type de document : texte imprimé Auteurs : Xiaoping Zhang, Auteur ; Hsiaotao T. Bi, Auteur Année de publication : 2010 Article en page(s) : pp 6862–6869 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Fluidized  bed  Turbulent  Catalyst  powders. Résumé : Turbulent fluidized beds have been recognized as very effective gas−solids contacting devices because of their outstanding performance in gas−solids contact, heat transfer, and mass transfer. To characterize the void behavior, which governs the hydrodynamics and the efficiency of operation of turbulent fluidized beds, an optical fiber probe with a separation distance of 5 mm between the two measuring tips has been used to measure the axial and radial profiles of the bubble/void parameters in a turbulent fluidized bed over a gas velocity range of 0.4−1.0 m/s. Experiments were carried out in a Plexiglas column with an inner diameter of 0.19 m and a height of 5.5 m. Fluid cracking catalyst (FCC) powders with a mean size of 78 μm were used as bed particles, and air was used as the fluidizing gas. Signals from the optical fiber probe were used to obtain the rise velocity and the chord length of voids at various spatial positions and superficial gas velocities. The results show that, in the turbulent fluidization regime, the void size and the void rise velocity have a relatively uniform distribution along the radial direction in the bed. Based on the assumption that bubble splitting is dominant over bubble coalescence at high superficial gas velocities, a modified bubble coalescence−splitting balance model was found to give reasonable agreement with the measured void size profiles. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901715z [article] Study on void behavior in a turbulent fluidized bed with catalyst powders [texte imprimé] / Xiaoping Zhang, Auteur ; Hsiaotao T. Bi, Auteur . - 2010 . - pp 6862–6869. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 15 (Août 2010) . - pp 6862–6869 Mots-clés : Fluidized  bed  Turbulent  Catalyst  powders. Résumé : Turbulent fluidized beds have been recognized as very effective gas−solids contacting devices because of their outstanding performance in gas−solids contact, heat transfer, and mass transfer. To characterize the void behavior, which governs the hydrodynamics and the efficiency of operation of turbulent fluidized beds, an optical fiber probe with a separation distance of 5 mm between the two measuring tips has been used to measure the axial and radial profiles of the bubble/void parameters in a turbulent fluidized bed over a gas velocity range of 0.4−1.0 m/s. Experiments were carried out in a Plexiglas column with an inner diameter of 0.19 m and a height of 5.5 m. Fluid cracking catalyst (FCC) powders with a mean size of 78 μm were used as bed particles, and air was used as the fluidizing gas. Signals from the optical fiber probe were used to obtain the rise velocity and the chord length of voids at various spatial positions and superficial gas velocities. The results show that, in the turbulent fluidization regime, the void size and the void rise velocity have a relatively uniform distribution along the radial direction in the bed. Based on the assumption that bubble splitting is dominant over bubble coalescence at high superficial gas velocities, a modified bubble coalescence−splitting balance model was found to give reasonable agreement with the measured void size profiles. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901715z