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Gas back-mixing in a two-dimensional baffled turbulent fluidized bed / Yongmin Zhang in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8484–8491 Titre : Gas back-mixing in a two-dimensional baffled turbulent fluidized bed Type de document : texte imprimé Auteurs : Yongmin Zhang, Auteur ; Chunxi Lu, Auteur ; John R. Grace, Auteur Année de publication : 2008 Article en page(s) : p. 8484–8491 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Turbulent  fluidized Résumé : The effect of louver baffles on gas back-mixing was investigated in a large-scale two-dimensional fluidized bed of fluid catalytic cracking (FCC) particles with helium as tracer gas. The axial gas dispersion coefficient of the baffle-free fluidized bed first increased with increasing superficial gas velocity and then decreased after reaching a maximum near the onset of the turbulent flow regime. “Gulf streaming” of emulsion flow in the baffle-free bed determined the lateral profiles of tracer gas concentration. Solids back-mixing flux was greatly reduced by the addition of a layer of louver baffles, while solids mixing above the baffle layer was enhanced. The modified baffled fluidized bed with multilayer louver baffles not only provided a high efficiency of gas−solids contacting but also greatly suppressed the back-mixing of both gas and solids. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800906n [article] Gas back-mixing in a two-dimensional baffled turbulent fluidized bed [texte imprimé] / Yongmin Zhang, Auteur ; Chunxi Lu, Auteur ; John R. Grace, Auteur . - 2008 . - p. 8484–8491. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8484–8491 Mots-clés : Turbulent  fluidized Résumé : The effect of louver baffles on gas back-mixing was investigated in a large-scale two-dimensional fluidized bed of fluid catalytic cracking (FCC) particles with helium as tracer gas. The axial gas dispersion coefficient of the baffle-free fluidized bed first increased with increasing superficial gas velocity and then decreased after reaching a maximum near the onset of the turbulent flow regime. “Gulf streaming” of emulsion flow in the baffle-free bed determined the lateral profiles of tracer gas concentration. Solids back-mixing flux was greatly reduced by the addition of a layer of louver baffles, while solids mixing above the baffle layer was enhanced. The modified baffled fluidized bed with multilayer louver baffles not only provided a high efficiency of gas−solids contacting but also greatly suppressed the back-mixing of both gas and solids. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800906n

Systematic investigation of particle segregation in binary fluidized beds with and without multilayer horizontal baffles / Yongmin Zhang in Industrial & engineering chemistry research, Vol. 51 N° 13 (Avril 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 13 (Avril 2012) . - pp. 5022-5036 Titre : Systematic investigation of particle segregation in binary fluidized beds with and without multilayer horizontal baffles Type de document : texte imprimé Auteurs : Yongmin Zhang, Auteur ; Haibo Wang, Auteur ; Lili Chen, Auteur Année de publication : 2012 Article en page(s) : pp. 5022-5036 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Baffle  Multiple  layer  Fluidized  bed  Fluidization  Segregation Résumé : Particle segregation was systematically studied in a binary fluidized bed of inner diameter 0.286 m with fine FCC and coarse millet particles as flotsam and jetsam, respectively. Segregation efficiencies of both flotsam and jetsam, axial and radial fraction profiles were studied and analyzed systematically. A new developed horizontal baffle was examined to see its effects on particles segregation. Experimental results showed that the baffle-free bed could only get high-purity flotsam particles at very low gas velocities. However, both nearly pure jetsam and flotsam particles were obtainable at much higher gas velocities after four layers of new baffle are installed. A wider operating range suitable for particle segregation and greater axial fraction gradients were found in the baffled bed, further proving the baffle's effect on promoting particle segregation. This enables the baffled bed to be a promising continuous particle classifier in industry. Further analysis demonstrated that reduced bubble size, improve bubble flow distribution, and suppressed solid mixing are the intrinsic causes. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25777942 [article] Systematic investigation of particle segregation in binary fluidized beds with and without multilayer horizontal baffles [texte imprimé] / Yongmin Zhang, Auteur ; Haibo Wang, Auteur ; Lili Chen, Auteur . - 2012 . - pp. 5022-5036. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 13 (Avril 2012) . - pp. 5022-5036 Mots-clés : Baffle  Multiple  layer  Fluidized  bed  Fluidization  Segregation Résumé : Particle segregation was systematically studied in a binary fluidized bed of inner diameter 0.286 m with fine FCC and coarse millet particles as flotsam and jetsam, respectively. Segregation efficiencies of both flotsam and jetsam, axial and radial fraction profiles were studied and analyzed systematically. A new developed horizontal baffle was examined to see its effects on particles segregation. Experimental results showed that the baffle-free bed could only get high-purity flotsam particles at very low gas velocities. However, both nearly pure jetsam and flotsam particles were obtainable at much higher gas velocities after four layers of new baffle are installed. A wider operating range suitable for particle segregation and greater axial fraction gradients were found in the baffled bed, further proving the baffle's effect on promoting particle segregation. This enables the baffled bed to be a promising continuous particle classifier in industry. Further analysis demonstrated that reduced bubble size, improve bubble flow distribution, and suppressed solid mixing are the intrinsic causes. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25777942