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Operating Characteristics of a Continuous Two-Stage Bubbling Fluidized-Bed Process
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 Title & Authors
Operating Characteristics of a Continuous Two-Stage Bubbling Fluidized-Bed Process
Youn, Pil-Sang; Choi, Jeong-Hoo;
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 Abstract
Flow characteristics and the operating range of gas velocity was investigated for a two-stage bubbling fluidized-bed (0.1 m-i.d., 1.2 m-high) that had continuous solids feed and discharge. Solids were fed in to the upper fluidized-bed and overflowed into the bed section of the lower fluidized-bed through a standpipe (0.025 m-i.d.). The standpipe was simply a dense solids bed with no mechanical or non-mechanical valves. The solids overflowed the lower bed for discharge. The fluidizing gas was fed to the lower fluidized-bed and the exit gas was also used to fluidize the upper bed. Air was used as fluidizing gas and mixture of coarse (< in diameter and in apparent density) and fine (< in diameter and in apparent density) particles were used as bed materials. The proportion of fine particles was employed as the experimental variable. The gas velocity of the lower fluidized-bed was defined as collapse velocity in the condition that the standpipe was emptied by upflow gas bypassing from the lower fluidized-bed. It could be used as the maximum operating velocity of the present process. The collapse velocity decreased after an initial increase as the proportion of fine particles increased. The maximum took place at the proportion of fine particles 30%. The trend of the collapse velocity was similar with that of standpipe pressure drop. The collapse velocity was expressed as a function of bulk density of particles and voidage of static bed. It increased with an increase of bulk density, however, decreased with an increase of voidage of static bed.
 Keywords
Gas Fluidized Bed;Multi-Fluidized-Bed;Hydrodynamics;Standpipe;Pressure Profile;
 Language
Korean
 Cited by
1.
Effects of angle on the transport velocity in an inclined fluidized-bed,;;;;;;;

The Korean Journal of Chemical Engineering, 2015. vol.32. 12, pp.2542-2549 crossref(new window)
1.
Effects of angle on the transport velocity in an inclined fluidized-bed, Korean Journal of Chemical Engineering, 2015, 32, 12, 2542  crossref(new windwow)
2.
Properties of an inclined standpipe for feeding solids into a bubbling fluidized-bed, Korean Journal of Chemical Engineering, 2017, 34, 9, 2541  crossref(new windwow)
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