Difference between revisions of "Mapping of Regimes"

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(Region A', Miyauchi et al)
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=== Region A', Miyauchi et al  ===
 
=== Region A', Miyauchi et al  ===
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Considering Squires’ criteria and observed industrial performance, '''Ikeda''' modified the criteria as shown in Table I

Revision as of 10:46, 23 November 2020

The Geldart Classification of Particles

Geldart came up with four clearly recognizable kinds of particle behavior. From smallest to largest particle, they are as follows:

Group C: cohesive, or very fine powders. Normal fluidization is extremely difficult for these solids because interparticle forces are greater than those resulting from the action of the gas.

Group A: aeratable, or materials having a small mean particle size and/or low particle density ( < ~ 1.4 g/cm3 ). These solids fluidize easily, with smooth fluidization at low gas velocities and controlled bubbling with small bubbles at higher gas velocities. FCC catalyst is representative of these solids.

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                         Region A': Range of properties for well-behaved FCC catalyst; from Miyauchi et al.

Group B: sandlike, or most particles of size 40 μm < dp < 500 μm and density 1.4 < ps < 4 g/cm3. These solids fluidize well with vigorous bubbling action and bubbles that grow large.

Group D: spoutable, or large and/or dense particles. Deep beds of these solids are difficult to fluidize.

Region A', Miyauchi et al

Considering Squires’ criteria and observed industrial performance, Ikeda modified the criteria as shown in Table I