Solids Concentration and Velocity Patterns in Circulating Fluidized Beds

Hartge, Ernst‐Ulrich; Rensner, Detlef; Werther, Joachim

doi:10.1016/b978-0-08-036225-0.50020-4

Cited by 97 publications

(65 citation statements)

References 4 publications

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“…An optical measuring system, similar in concept to the one proposed by Hartge etal. [24], has been developed. Using this system, the flow structure in a cold-flow CFB unit has been investigated by measuring local solids concentration and local axial solids velocity as a function of the radial position in the dser tube.…”

Section: Discussionmentioning

confidence: 99%

“…[24] showed, the relation between the amplified output voltage U of the photo diode and the local particle concentration e, is given by:…”

Section: Validationandcalibrationmentioning

confidence: 99%

“…[24]. To improve tbe quality of the signals the monoglass fibre, as used by Hartge et al, has been replaced by a bifurcated multi-glass fibre (diameter of glass fibres: 15 p,m).…”

Section: Development Of An Optical Probe Systemmentioning

confidence: 99%

“…[6,7,[24][25][26] developed two optical probe systems. The first system was based on light absorption due to the presence of solid particles in a certain control volume between an emitting and a receiving fibre.…”

Section: Opticaltechniquesmentioning

confidence: 99%

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Measurements of solids concentration and axial solids velocity in gas-solid two-phase flows

et al. 1996

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Several techniques rep',med in the literature for measuring solids concentration and solids velocity in (dense) gas-selid two-phase flow have been briefly reviewed, An optical measuring system, based on detection of light reflected by Ihe suspended paRicles, has bece developed to measure local solids concentration and local axial solids velocity in dense gas-solid two phase flows. This system has bean applied to study hydrodynamics of a co)d-flow circulating fluidized bed unit operated in the dense flow regime (a": 7.:5-15 m s-i and G~ ~ 100-400 kg m-2 s I). With increaslng solids mass flux, at constant superficial gas velocity, lateud solids sngregation became more pronounced (i.e. extent of development of core-annulus structure) while the radial profiles of axial solids velocity hardly changed. A decre:,se in superficialgas velocity, at constant solids mass flux, also augmented the lateral solids segregation. The axial solids velocity decreased over the entire tube radius, although the shape of the profiles showed no strong dependence with respect to the superficial gas velocity. Average solids mass fluxes calculated from the measured local values of solids concentration and solids velocity exceeded the imposed solids mass flux. a finding which could be explained by the downflow observed visually of solid particles close to the tuba wall In addition, cross-sectional averaged solids concentrations obtained on the basis of the optical measuring system and those obtained from the pressure gradient measurements showed satisfactory agreement.

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Section: Discussionmentioning

confidence: 99%

“…[24] showed, the relation between the amplified output voltage U of the photo diode and the local particle concentration e, is given by:…”

Section: Validationandcalibrationmentioning

confidence: 99%

“…[24]. To improve tbe quality of the signals the monoglass fibre, as used by Hartge et al, has been replaced by a bifurcated multi-glass fibre (diameter of glass fibres: 15 p,m).…”

Section: Development Of An Optical Probe Systemmentioning

confidence: 99%

Section: Opticaltechniquesmentioning

confidence: 99%

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Measurements of solids concentration and axial solids velocity in gas-solid two-phase flows

et al. 1996

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“…Horio et al (1988) and Hartge et al (1988) detected clusters in fluidized beds. Sinclair and Jackson (1989) applied the granular flow model to a fully developed gas-solid flow.…”

Section: Literature Reviewmentioning

confidence: 99%

Development of Criteria and Identification of Particle Cluster Size Based on Measurements of Void Fraction in Gas-Solid Systems

Roelant¹,

Gokaltun²

2009

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Scale‐up effect of riser reactors: Particle velocity and flow development

Yan

Zhu

2005

AIChE Journal

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in Wiley InterScience (www.interscience.wiley.com).The influence of riser diameter on the axial and radial particle velocity profiles and flow development is studied in a 10 m high twin-riser system . Cross-sectional average particle velocity is somewhat lower for the larger riser with a steeper radial particle velocity profile. The flow development in the riser center is nearly instant with the particle velocity remaining high. There is no significant difference for the two risers in the center region. In the wall region, the flow development is significantly slower and the particle velocity of the smaller riser is higher. The flow development slows down in the larger riser. In all locations measured, there was a clear dependency between the local particle velocity and solids concentration of both risers. Gas distribution and particle aggregation are considered the key factors that influence the local hydrodynamics in the twin-riser system.

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Solids Concentration and Velocity Patterns in Circulating Fluidized Beds

Cited by 97 publications

References 4 publications

Measurements of solids concentration and axial solids velocity in gas-solid two-phase flows

Measurements of solids concentration and axial solids velocity in gas-solid two-phase flows

Development of Criteria and Identification of Particle Cluster Size Based on Measurements of Void Fraction in Gas-Solid Systems

Scale‐up effect of riser reactors: Particle velocity and flow development

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