Experimental study on the influence of bed material on the scaling of solids circulation patterns in 3D bubbling gas–solid fluidized beds of glass and polyethylene using positron emission particle tracking

Laverman, JA; Fan, Xianfeng; Ingram, Andrew; Annaland, van M Martin Sint; Parker, D.J.; Seville, Jpk; Kuipers, J.A.M.

doi:10.1016/j.powtec.2012.03.011

Cited by 69 publications

(42 citation statements)

References 16 publications

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“…The simulation technique and numerical parameters for bubbling fluidized beds were validated previously using time-averaged void fraction profiles [28] as well as bubble dynamics [29] in the bed. Nevertheless, to completely validate solids motion, the experimental setup by Laverman et al [35] is simulated and comparisons with solids velocity measurements are presented in Section 4.1. Validated simulations are subsequently used to predict the effect of bed diameter D (for H 0 = 50 cm) in Section 4.2 followed by effect of initial bed height H 0 (for D = 50 cm).…”

Section: Resultsmentioning

confidence: 99%

“…Laverman et al [35] employed position emission particle tracking (PEPT) to track radioactive tracer particles in a 30 cm diameter fluidized bed. Two different bed materials were chosenglass (400-600 μm, 2500 kg/m 3 ) and LLDPE (1000-1300 μm, 800 kg/ m 3 ) with similar Ar/Re mf to ensure similar dynamics based on Glicksman's scaling laws [44].…”

Section: Validationmentioning

confidence: 99%

“…17). Even though overall bed dynamics are similar [35], these differences elucidate the impact of particle properties on gas distribution in the bed [15] which will be examined in detail in following studies.…”

Section: Solids Circulationmentioning

confidence: 99%

“…The simulation setup and fluidization metrics are briefly described in Sections 2 and 3 respectively, while detailed description can be found in [29]. Although the simulation setup has been validated previously in terms of bubble dynamics [29], solids velocity predictions are compared with experimental measurements by Laverman et al [35] in Section 4.1. Validated simulations are subsequently used to analyze the effect of scale on both bubble dynamics and solids circulation in Sections 4.2 and 4.3, respectively.…”

Section: Introductionmentioning

confidence: 99%

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Study of the effect of reactor scale on fluidization hydrodynamics using fine-grid CFD simulations based on the two-fluid model

et al. 2016

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Reliable scale-up of fluidized beds is essential to ensure that analysis and performance optimization at lab-scale can be applied to commercial scales. However, scaling fluidized beds for dynamic similarity continues to be challenging because flow hydrodynamics at lab-scale are largely influenced by bed geometry making extrapolation of conclusions to large-scales infeasible. Therefore, this study is focused on analyzing the effect of bed geometry on the fluidization hydrodynamics using large-scale CFD simulations. The two fluid model (TFM) is employed to describe the solids motion efficiently and simulations are conducted for fluidization of 1150 μm LLDPE and 500 μm glass beads in beds of different sizes (diameter D = 15-70 cm and initial bed height H 0 = 10-75 cm). The hydrodynamics are subsequently investigated qualitatively using time-resolved visualizations, bubble centroid and solids velocity maps as well as quantitatively using detailed bubble statistics and solids circulation metrics. It is shown that as the bed diameter is increased, average bubble sizes decrease although similar-sized bubbles rise faster because of lower wall resistance, both factors contributing to faster solids circulation. On the other hand, fluidization hydrodynamics in 50 cm diameter bed are relatively insensitive to the choice of H 0 and similarities in solids circulation patterns are observed in shallow beds as well as in the lower regions of deep beds. Finally, it is shown that the size and spatial-distribution of bubbles is crucial for maintaining dynamic similarity of bubbling beds. Specifically, the bed dimensions (D, H 0 ) must ensure that (a) bubbles are typically much smaller than the bed diameter and (b) solids circulation patterns are similar across scales of interest. Overall, insights from this study can be used for describing the gas distribution and solids motion more accurately for better design of commercial beds.

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Section: Resultsmentioning

confidence: 99%

Section: Validationmentioning

confidence: 99%

Section: Solids Circulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Study of the effect of reactor scale on fluidization hydrodynamics using fine-grid CFD simulations based on the two-fluid model

et al. 2016

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“…Since dense gas-solid flows are typically opaque to visible light, this limits the use of the technique to 2D systems although most of the fluidized beds are cylindrically shaped [5]. To circumvent this limitation, some techniques were developed to characterize experimental 3D beds by means of non-intrusive tomography (electric capacitance tomography [6] or nuclear tomography [7]), particle tracking techniques [8][9][10], optical and capacitance probes [11,12] or pressure transducers [13]. Excluding particle tracking techniques, which are developed to follow the motion of single particles, the above mentioned techniques allow the detection of local voidage in the bed, i.e.…”

Section: Introductionmentioning

confidence: 99%

Use of α -shapes for the measurement of 3D bubbles in fluidized beds from two-fluid model simulations

et al. 2016

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A geometrical technique based on shape construction was employed to reconstruct the simulated domain of 3D bubbles in a gas-solid fluidized bed, from Two-Fluid Model (TFM) simulations. The Delaunay triangulation of the cloud of points that represent volume fraction iso-surfaces in transient TFM simulations was filtered by means of the so-called α-shapes, allowing a topologically accurate description of 3D bubbles within a fluidized bed. Consequently, individual 3D bubble properties such as size and velocity were measured. Simulated bubble characteristics were further compared to those measured on pseudo-2D bed facilities by image techniques in order to illustrate the effect of the bed geometry on the bubbling behaviour under mimicked operational conditions.

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Multiscale Modeling of Multiphase Flows

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Peters

et al. 2022

Multiphase Flows for Process Industries

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Experimental study on the influence of bed material on the scaling of solids circulation patterns in 3D bubbling gas–solid fluidized beds of glass and polyethylene using positron emission particle tracking

Cited by 69 publications

References 16 publications

Study of the effect of reactor scale on fluidization hydrodynamics using fine-grid CFD simulations based on the two-fluid model

Study of the effect of reactor scale on fluidization hydrodynamics using fine-grid CFD simulations based on the two-fluid model

Use of α -shapes for the measurement of 3D bubbles in fluidized beds from two-fluid model simulations

Multiscale Modeling of Multiphase Flows

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