Entrapment and Elutriation From Fluidized Beds

Kunii, Daizō; Levenspiel, Octave

doi:10.1252/jcej.2.84

Cited by 23 publications

(4 citation statements)

References 5 publications

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“…Hence, entrainment increases as the freeboard height is reduced. Kunii and Levenspiel [31] presented a simple flow model to represent the complex phenomena occurring in the freeboard. Their model lumped velocities and other quantities, but still incorporated the main features of freeboard behavior, such as the ejection of clumps of solids into the freeboard, followed by the upflow, downflow, and breakup of these clumps.…”

Section: Figurementioning

confidence: 99%

Entrainment and Elutriation from Fluidized Beds

Kunii

1991

Fluidization Engineering

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Section: Figurementioning

confidence: 99%

Entrainment and Elutriation from Fluidized Beds

Kunii

1991

Fluidization Engineering

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“…The first studies on the generalization of experimental data on the removal of a small fraction from the layer were reported in works [23][24][25]. It is postulated that under conditions of equilibrium between the concentrations of small particles in the layer and in the entrainment, the rate of removal of small particles is expressed by the following dependence:…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

“…where w is the operating fluidization rate, m/s; u s is the velocity of particulate matter in the gas flow, m/s; Fr is Froude's criterion; Re -Reynolds criterion; d -average diameter of solid particles, m; D -diameter of the apparatus, m; H l , H s -respectively, the height of the suspended layer and the superlayer (separation) space, m; ρ p , ρ -respectively, the density of solid particles and gas, kg/m 3 . Paper [25] proposes a modified entrainment constant, which depends on such parameters as the cross-section of the fluidized layer, the height of the superlayer space, and several experimental constants. In works [29,30], the authors propose to take into account the mass fraction of the fine fraction in the layer when determining the constant of the rate of carryover.…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

Design of a shelf pneumatic classifier for separating a polydisperse mixture of granulated superphosphate

Yukhymenko

Ostroha

Bocko

2022

EEJET

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The object of this study is a polydisperse mixture of granular superphosphate. It is emphasized that existing technologies of granulation and processing of granules lead to the formation of dusty fractions of small particles. The content of small fractions in the finished product should be minimal and, in connection with this problem, the task is to remove small particles from the mixture. The purpose of the current experimental study is to classify a polydisperse mixture of granular superphosphate in a pneumatic classifier. The device includes an inclined perforated shelf with an unloading space between its end and the wall of the apparatus. It has been experimentally revealed that the maximum efficiency of extraction into the entrainment of small particles is achieved with a width of the discharge space equal to 0.5 of the length of the cross-sectional side of the apparatus; the degree of perforation of the shelf is 5 %; the angle of inclination of the shelf is 25–30°; the speed of the gas flow in the free section of the apparatus is 3.7 m/s. It is shown that the degree of extraction into the entrainment of a small fraction less than 1 mm in size reaches 70–75 %, the content of the small fraction in the carry-over is 96–98 %, and the large fraction is less than 5 %. By processing experimental data, an empirical equation was built that makes it possible to determine the concentration of particles in the gas stream for individual fractions of the material. It is shown that due to the implementation of an active aerodynamic weighing mode, the shelf pneumatic classifier works at specific loads for air flow rate less than the typical designs of fluidized bed separators. It is noted that the effective operation of the shelf pneumatic classifier in the production of granular mineral fertilizers is ensured at a productivity of no more than 10–12 t/h. With greater productivity, there is a need to install several devices in the technological line

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“…There have appeared only few papers which deal with (2), based on an understanding of the motion of fluidized particles. On the other hand, the motion of entrained particles is closely related both to solidholdup in the beds, and the gas velocity.…”

Section: ) Transport Disengaging Height6)mentioning

confidence: 99%