Investigation of particle velocity in FCC gas-fluidized beds based on different measurement techniques

Tebianian, Sina; Dubrawski, Kristian L.; Ellis, Naoko; Cocco, Ray; Hays, Roy; Karri, S.B. Reddy; Leadbeater, Thomas; Parker, D.J.; Chaouki, Jamal; Jafari, Rouzbeh; García‐Triñanes, Pablo; Seville, Jonathan; Grace, John R.

doi:10.1016/j.ces.2015.01.049

Cited by 48 publications

(43 citation statements)

References 14 publications

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“…The results show that the overall axially‐averaged axial velocity of glass bead particles is positive at the centre region of the column, and negative near the wall, which shows that the solids are going up from the centre region of the column (r/R = 0–0.62) and coming down near the wall region (r/R ≥ 0.63). This finding is consistent with previous studies …”

Section: Resultssupporting

confidence: 94%

“…It is noteworthy that larger tracer particle with a similar density of the solid particles of the fluidized bed should be able to track with confidence the smaller particle sizes in the fluidized bed. This is because the particles in the gas‐solid fluidized bed usually do not move as single isolated particles but as a cluster . Each single particle is attached to a solid aggregate in the dense bed and moves with it until the solid aggregate breaks up.…”

Section: Measurement Techniquesmentioning

confidence: 99%

“…Mostoufi et al showed that all studied parameters were affected by the superficial gas velocity, and were independent of the size of the tracer. In RPT experiments, Tebianian et al used scandium as a tracer particle with size and density different from the solid particle used; tracer diameter was 400 μm, which was 4‐times greater than particle size (107 μm) but with the same density. In our experiment, a total of 28 NaI scintillation detectors were positioned around the column.…”

Section: Measurement Techniquesmentioning

confidence: 99%

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Assessment of scale‐up dimensionless groups methodology of gas‐solid fluidized beds using advanced non‐invasive measurement techniques (CT and RPT)

Efhaima

Al‐Dahhan

2017

Can J Chem Eng

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The most common scale‐up methodology for gas‐solid fluidized bed reactors that has been reported in the literature is based on matching the dimensionless groups. This scale‐up methodology in the literature has been validated by only measuring global hydrodynamic parameters (overall holdups and pressure drop, etc.) without details. Therefore, in this work, we have applied advanced non‐invasive measurement techniques, gamma‐ray computed tomography (CT) and radioactive particle tracking (RPT) techniques, for the first time to evaluate such scale‐up methodology by measuring local hydrodynamic parameters. The results obtained demonstrate that the reported set of the dimensionless groups are not adequate in capturing all the interplay phenomena for achieving similarity in the local hydrodynamic parameters when the proposed set of dimensionless groups has been matched using two sizes of fluidized beds of 0.14 m and 0.44 m and sets of operating conditions. This finding confirms that the local measurements of the hydrodynamic parameters are essential for detailed assessment of scale‐up methodologies.

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Section: Resultssupporting

confidence: 94%

Section: Measurement Techniquesmentioning

confidence: 99%

Section: Measurement Techniquesmentioning

confidence: 99%

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Assessment of scale‐up dimensionless groups methodology of gas‐solid fluidized beds using advanced non‐invasive measurement techniques (CT and RPT)

Efhaima

Al‐Dahhan

2017

Can J Chem Eng

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“…For the case of Dubrawski (case A, Figure 3(a)), the lower section bed is 0.96 m high and 0.133 m of diameter, and the upper section is 0.59 m high and 0.19 m of diameter, Dubrawski using different advanced experimental techniques in the "Traveling fluidized bed" to determine local voidage, bed expansion and so on. This work was further extended by Tebianian et al [11] who using different advanced techniques to measure the particle velocity in the same "traveling fluidized bed". The simulation case of Zhu (case B, Figure 3(b)) was carried out for a bed of 2.464 m high and 0.267 m of diameter.…”

Section: The Benchmark Simulation Setupmentioning

confidence: 94%

Triple Phase Simulation of Bubbling Fluidized Beds of Geldart “A” Particles with a Bubble-Based Drag Model

Wang¹,

Chen²

2017

dtcse

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Abstract.A triple-phase numerical model was developed for the simulations of gas-solid bubbling fluidized beds with Geldart "A" particles. In the model, the gas-solids suspension was modeled as a primary gas phase presented in the emulsion, a secondary gas phase presented in the bubble, and a third phase consisting of solids. A bubble-based drag model was derived taking into account of the heterogeneous flow structures of the emulsion phase. The KTGF model was used to describe the solid phase stresses. Simulations were conducted for two different scales bubbling fluidized beds of Group "A" particles. Mesh independences were confirmed up to a radial grid size of 200 times particle diameter, and the sensitivity of the transitional results on the time-steps was investigated. The predicted bed expansion and the voidage distribution, axial and radial solids volume fraction profiles, and the solids velocity vectors have been validated against literature data.

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“…The optical fiber probe is intrusive, and therefore interferes to some extent with the flow field being measured. Furthermore, electrostatic and van de Waals forces may cause fine particles to adhere to the optical probe surface, leading to significant loss of data [38]. Moreover, for the measurement of solids volume concentrations, the calibration process is quite difficult since it is practically impossible to realize homogeneous gas-solid suspension [39].…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Monitoring of particle motions in gas-solid fluidized beds by electrostatic sensors

Yang

Zhang

et al. 2017

Powder Technology

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P TACCEPTED MANUSCRIPT Electrostatic charge signals in the fluidized bed contain much dynamic information on particle motions, which are poorly understood and explored. In this work, correlation velocities of Geldart B and D particles were measured, analyzed and compared by induced electrostatic sensors combined with cross-correlation method in the fluidized bed. The results indicated that the average correlation velocity of particle clouds increased and the normalized probability density distributions of correlation velocities broadened when the superficial gas velocity increased in the dense-phase region. Both upward and downward correlation velocities could be acquired in the dynamic bed level region. Under the same excess gas velocity, the average correlation velocity of Geldart D particles was significantly smaller than that of Geldart B particles, which was caused by the smaller bubble sizes caused by the dominant bubble split over coalescence and less volume of A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT 2 gas forming bubbles for Geldart D particles. The experimental results verified the reliability and repeatability of particle correlation velocity measurement by induced electrostatic sensors in the gas-solid fluidized bed, which provides definite potential in monitoring of particle motions.

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Investigation of particle velocity in FCC gas-fluidized beds based on different measurement techniques

Cited by 48 publications

References 14 publications

Assessment of scale‐up dimensionless groups methodology of gas‐solid fluidized beds using advanced non‐invasive measurement techniques (CT and RPT)

Assessment of scale‐up dimensionless groups methodology of gas‐solid fluidized beds using advanced non‐invasive measurement techniques (CT and RPT)

Triple Phase Simulation of Bubbling Fluidized Beds of Geldart “A” Particles with a Bubble-Based Drag Model

Monitoring of particle motions in gas-solid fluidized beds by electrostatic sensors

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