Documents disponibles écrits par cet auteur

CPFD simulation of a fast fluidized bed steam coal gasifier feeding section / Alireza Abbasi in Chemical engineering journal, Vol. 174 N° 1 (Octobre 2011) 

Public ISBD [article]  in Chemical engineering journal > Vol. 174 N° 1 (Octobre 2011) . - pp.341-350 Titre : CPFD simulation of a fast fluidized bed steam coal gasifier feeding section Type de document : texte imprimé Auteurs : Alireza Abbasi, Auteur ; Paul E. Ege, Auteur ; Hugo I. De Lasa, Auteur Année de publication : 2012 Article en page(s) : pp.341-350 Note générale : Génie chimique Langues : Anglais (eng) Mots-clés : Coal  gasification  Fluidized  beds  Computational  particle  fluid  dynamics  Suspension  chocking Résumé : Coal gasification in fluidized beds is a process that can be strongly influenced by gas–solid suspension flow patterns. Fast fluidized beds can be designed to maximize coal gasification yields providing an optimum syngas composition with minimum operational upsets. In order to accomplish this, a comprehensive model for steam coal gasification is valuable. With this end, a 2D CPFD (computational particle fluid dynamics) dynamic model is considered in the present study. The proposed model uses a Lagrangian–Eulerian approach and describes the flow patterns in the gasifier feeding section, as well as the local particle velocities, particle solid fractions and gas composition. As a reference and for comparison, an ideal PFR (plug flow reactor) model is also considered. It is found that compositions from the 2D CPFD model provide close gas compositions with respect to the PFR. It is observed that the 2D CPFD model is valuable for predicting particle flows in the feeding near region keeping it unaffected by fast fluidized bed upsets such as suspension chocking. It is also found that the 2D CPFD model is particularly useful for describing fast fluidized beds operation involving significant amounts of rich ash recycled feeds. ISSN : 1385-8947 En ligne : http://www.sciencedirect.com/science/article/pii/S1385894711009752 [article] CPFD simulation of a fast fluidized bed steam coal gasifier feeding section [texte imprimé] / Alireza Abbasi, Auteur ; Paul E. Ege, Auteur ; Hugo I. De Lasa, Auteur . - 2012 . - pp.341-350. Génie chimique Langues : Anglais (eng) in Chemical engineering journal > Vol. 174 N° 1 (Octobre 2011) . - pp.341-350 Mots-clés : Coal  gasification  Fluidized  beds  Computational  particle  fluid  dynamics  Suspension  chocking Résumé : Coal gasification in fluidized beds is a process that can be strongly influenced by gas–solid suspension flow patterns. Fast fluidized beds can be designed to maximize coal gasification yields providing an optimum syngas composition with minimum operational upsets. In order to accomplish this, a comprehensive model for steam coal gasification is valuable. With this end, a 2D CPFD (computational particle fluid dynamics) dynamic model is considered in the present study. The proposed model uses a Lagrangian–Eulerian approach and describes the flow patterns in the gasifier feeding section, as well as the local particle velocities, particle solid fractions and gas composition. As a reference and for comparison, an ideal PFR (plug flow reactor) model is also considered. It is found that compositions from the 2D CPFD model provide close gas compositions with respect to the PFR. It is observed that the 2D CPFD model is valuable for predicting particle flows in the feeding near region keeping it unaffected by fast fluidized bed upsets such as suspension chocking. It is also found that the 2D CPFD model is particularly useful for describing fast fluidized beds operation involving significant amounts of rich ash recycled feeds. ISSN : 1385-8947 En ligne : http://www.sciencedirect.com/science/article/pii/S1385894711009752

Slip velocity in downer reactors: drag coefficient and the influence of operational variables / Mohammad Ashraful Islam 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 6735–6744 Titre : Slip velocity in downer reactors: drag coefficient and the influence of operational variables Type de document : texte imprimé Auteurs : Mohammad Ashraful Islam, Auteur ; Stefan Krol, Auteur ; Hugo I. De Lasa, Auteur Année de publication : 2010 Article en page(s) : pp 6735–6744 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Slip  velocity  Operational  variables. Résumé : Cluster formation in downer reactors is considered a most important factor influencing slip velocity between the flowing phases. This study investigates the formation of clusters using CREC-GS-Optiprobes. This probe is a nonintrusive device that records information from a well-defined optical measuring volume. This probe can provide accurate measurements tracking closely gas−solid flows in downer units. This study shows that cluster drag coefficients can be correlated as function of both Reynolds number and number of particles contained in agglomerates. This yields a close to linear relationship between cluster size and average slip velocity. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901466p [article] Slip velocity in downer reactors: drag coefficient and the influence of operational variables [texte imprimé] / Mohammad Ashraful Islam, Auteur ; Stefan Krol, Auteur ; Hugo I. De Lasa, Auteur . - 2010 . - pp 6735–6744. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 15 (Août 2010) . - pp 6735–6744 Mots-clés : Slip  velocity  Operational  variables. Résumé : Cluster formation in downer reactors is considered a most important factor influencing slip velocity between the flowing phases. This study investigates the formation of clusters using CREC-GS-Optiprobes. This probe is a nonintrusive device that records information from a well-defined optical measuring volume. This probe can provide accurate measurements tracking closely gas−solid flows in downer units. This study shows that cluster drag coefficients can be correlated as function of both Reynolds number and number of particles contained in agglomerates. This yields a close to linear relationship between cluster size and average slip velocity. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901466p