Particle velocities and their residence time distribution in the riser of a CFB

Chan, Chian W.; Seville, Jonathan; Parker, D.J.; Baeyens, Jan

doi:10.1016/j.powtec.2010.05.008

Cited by 72 publications

(41 citation statements)

References 27 publications

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“…Besides, it can be inferred from Fig. 5 that the slip velocity between gaseous phase and particle phase is about two, which is in agreement with the findings of Chan (u = 1.7-2.3) [29]. Thus, it can be concluded credibly that the assumed expression of variable gaseous velocity along the riser height (i.e.…”

Section: Results Of Hydrodynamic Model and Establishment Of Ideal Reasupporting

confidence: 88%

“…Regarding the solid hold-up profile in circulating fluidized bed, while some studies have revealed an axial solid hold-up profile with an inflection point for which it is referred to as the S-profile, other studies indicate that an exponential solid hold-up profile exists with an acceleration zone at the bottom of the riser rather than a dense bed [29]. The type of solid hold-up profile (S-profile, C-profile, exponential profile, etc.)…”

Section: Results Of Hydrodynamic Model and Establishment Of Ideal Reamentioning

confidence: 99%

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An integrated methodology for the modeling of Fluid Catalytic Cracking (FCC) riser reactor

Yang

Zhao

et al. 2014

Appl Petrochem Res

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Modeling description of the riser reactor is a highly interesting issue in the development of FCC process. However, one of the challenging problems in the modeling of FCC riser reactors is that sophisticated flow-reaction models with high accuracy need long computational time, while simple flow-reaction models give rise to results with fast computation but low accuracy. This dilemma requires new type of coupled flow-reaction models. The goal of this study was to propose a novel integrated model with timeefficient computation and acceptable accuracy. The integrated model, named equivalent reactor network (ERN) model, was established based on Aspen Plus simulator with considering gas-solid hydrodynamics via built-in modules and catalytic reactions via external FORTRAN subroutines, as well as lump mixtures characterized by real components. Through comparing with pilot-scale experimental data and industrial plant data in two case studies, the developed ERN model was justified to be capable of precisely and quickly modeling FCC riser reactors. Furthermore, the proposed methodology is expected to be readily applied to studies on the dynamic simulation, optimization, and control of FCC units in future studies.

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Section: Results Of Hydrodynamic Model and Establishment Of Ideal Reasupporting

confidence: 88%

Section: Results Of Hydrodynamic Model and Establishment Of Ideal Reamentioning

confidence: 99%

An integrated methodology for the modeling of Fluid Catalytic Cracking (FCC) riser reactor

Yang

Zhao

et al. 2014

Appl Petrochem Res

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“…The performance of a fluidized bed is highly influenced by the mixing of particles. Solids mixing has thus been a subject of continued interest of study in fluidization engineering since the 1950s (see review articles [1][2][3][4][5][6][7][8] ) and has developed into a broad topic. Mixing dynamics in a dense (bubbling/ slugging/turbulent) fluidized bed 1,2 are much different from those in a fluidized bed riser.…”

Section: Introductionmentioning

confidence: 99%

Quantifying lateral solids mixing in a fluidized bed by modeling the thermal tracing method

Liu

2011

AIChE Journal

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Thermal tracing is a simple method for studying solids mixing in fluidized beds. However, the measurement of temperatures is influenced by both mixing and heat transfer, which limits its usefulness for inferring mixing quantitatively. In this work, a semiempirical model is developed to quantify lateral solids mixing in fluidized beds. The model couples the tracer mass balance, the enthalpy balance of tracers and bed particles, and the response dynamic of thermometers. A series of tests is pezrformed in a lab-scale fluidized bed, with particle sizes of 0.28-0.45, 0.45-0.6, 0.6-0.

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“…First approaches to develop a "work map" of the riser operation were presented by, for example, Grace [1], Yerushalmi and Avidan [2], and Bai et al [3]. It was further developed by Chan et al [4] and Mahmoudi et al [5,6] for both Geldart A-and B-type powders: the operating gas velocity ( ) and the solids circulation flux ( ) jointly delineate different regimes, called, respectively, dilute riser flow (DRF), core-annulus flow (CAF) (possibly with a turbulent fluidized bed at the bottom of the riser (TFBB)), and dense riser upflow (DRU). For a given powder and its associated transport velocity, TR , the combination of and will determine the flow regime encountered.…”

Section: Introductionmentioning

confidence: 99%

Choking Affects the Operation Diagram of a CFB Riser

Zhang

Degrève

Baeyens

et al. 2014

Journal of Powder Technology

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Experiments in 3 different CFB risers have confirmed that common riser operations can be hampered in a well-defined (U, G) range where choking occurs. Geldart A-type powders were investigated. Experimental results of the choking velocity were empirically correlated, being about 30% lower than predicted by the correlation of Bi and Fan, but largely exceeding other predictions. Introducing the findings into the operation diagram presented by Mahmoudi et al. adds a region where stable riser operation is impossible. The adapted diagram enables CFB designers to better delineate the operating characteristics.

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Particle velocities and their residence time distribution in the riser of a CFB

Cited by 72 publications

References 27 publications

An integrated methodology for the modeling of Fluid Catalytic Cracking (FCC) riser reactor

An integrated methodology for the modeling of Fluid Catalytic Cracking (FCC) riser reactor

Quantifying lateral solids mixing in a fluidized bed by modeling the thermal tracing method

Choking Affects the Operation Diagram of a CFB Riser

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