Challenge problem: 1. Model validation of circulating fluidized beds

Panday, Rupen; Shadle, Lawrence J.; Shahnam, Mehrdad; Cocco, Ray; Issangya, Allan S.; Spenik, James S.; Ludlow, J. Christopher; Gopalan, Balaji; Shaffer, Frank; Syamlal, Madhava; Guenther, Chris; Karri, S.B. Reddy; Knowlton, T.M.

doi:10.1016/j.powtec.2014.02.010

Cited by 32 publications

(33 citation statements)

References 18 publications

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“…The underestimation of the pressure drop at higher solids circulation rate was mainly due to the simplification of the riser exit, and the 'simple' exit in the present simulation cannot account for the possible solids refluxing behavior at the top of the experimental riser, which would induce some particles from the top of the riser to flow toward the lower part of the riser and this would further increase the pressure loss across the experimental riser. Previous simulation works also indicated that the riser-only simulation tends to underestimate the pressure drop in the riser [21,61]. The full-loop simulation of the entire CFB system is expected to better predict the pressure drop in the riser.…”

Section: Comparison Between Model Results and Experimental Datamentioning

confidence: 99%

Effects of the riser exit geometries on the hydrodynamics and solids back-mixing in CFB risers: 3D simulation using CPFD approach

Shi

Lan

et al. 2015

Powder Technology

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Section: Comparison Between Model Results and Experimental Datamentioning

confidence: 99%

Effects of the riser exit geometries on the hydrodynamics and solids back-mixing in CFB risers: 3D simulation using CPFD approach

Shi

Lan

et al. 2015

Powder Technology

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“…However, the comparison could not be performed for high-solid-concentration flows since LDA is effective only for dilute suspensions. Panday et al [5] compared the time-average solid velocity in a CFB obtained by a dual multi fibre optical probe with data obtained by high-speed particle image velocimetry. Good agreement was observed between the results of these two techniques, but the comparison was limited to one operating condition and few locations.…”

Section: Introductionmentioning

confidence: 99%

Comparison of particle velocity measurement techniques in a fluidized bed operating in the square-nosed slugging flow regime

et al. 2016

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The novel “travelling fluidized bed” (TFB), operated under identical conditions, was deployed to compare alternate experimental measurement techniques for the investigation of solid motion in gas-fluidized beds operating in the square-nosed slugging regime. Measurements of particle velocity obtained by radioactive particle tracking (RPT – non-invasive at the Ecole Polytechnique de Montréal), positron emission particle tracking (PEPT – non-invasive at University of Birmingham), optical fibre probes (invasive at UBC) and borescopic high speed particle image velocimetry (invasive at PSRI) are compared for sand particles of mean diameter 292 μm. Significant differences between the time-average radial profiles of particle velocity are observed in many cases. The results provide valuable insights on the merits and challenges of advanced particle velocity measurement techniques.© 2015 Elsevier B.V. All rights reserved

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“…In the past, many researchers have attempted to characterize the hydrodynamics of the circulating fluidized bed (CFB) risers. Even the competitions involving hydrodynamic modeling of the CFB riser were arranged in the form of challenge problems for the last 20 years [1], [2], [3]. Researchers working in the multiphase flow area participated in these challenges.…”

Section: Introductionmentioning

confidence: 99%

Dynamic modeling of the circulating fluidized bed riser

Panday

Breault

2016

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Dynamic modeling is required to understand hydrodynamics of a circulating fluidized bed (CFB) riser as a function of time. The paper develops a dynamic model of the riser from the conservation of solids mass. Solids mass that flows out of the riser requires particle residence time to close the mass balance equation. The mean residence time of solids was derived as the riser length divided by the superficial riser gas velocity normalized by a ratio of solids concentration in the riser outlet to that in the riser itself. For bed materials including high-density polyethylene beads, glass beads, and cork, the percentage of solids concentration in the horizontal crossover pipe connecting the riser exit and the cyclone inlet was found to be 22% of the average concentration of solids in the riser. Upon finding the particle residence time, we calculated the solids flow rate out of the riser and along with the knowledge of solids flowing into the riser column we determined the riser inventory as a function of time. We used the estimated solids inventory to model overall pressure drop across the riser from the conservation of momentum. The momentum equation included the balance of pressure force by the hydrostatic head of solids, and the wall frictions due to gas and solids in a fully developed zone. The prediction of overall riser pressure drop compared well with its measured values at many dynamic conditions. Therefore, our dynamic model is useful for developing advanced control strategy or for improving existing control systems of the CFB plant. The residence time approach is also useful for the design of a transport reactor.

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Challenge problem: 1. Model validation of circulating fluidized beds

Cited by 32 publications

References 18 publications

Effects of the riser exit geometries on the hydrodynamics and solids back-mixing in CFB risers: 3D simulation using CPFD approach

Effects of the riser exit geometries on the hydrodynamics and solids back-mixing in CFB risers: 3D simulation using CPFD approach

Comparison of particle velocity measurement techniques in a fluidized bed operating in the square-nosed slugging flow regime

Dynamic modeling of the circulating fluidized bed riser

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