Effects and control of humidity and particle mixing in fluid-bed granulation
The novel technique of spraying binder liquid in pulses of short duration on a bubbling fluidized bed was used to study the effect liquid distribution, mixing, and relative humidity has on granule growth. Two important mixing zones in the fluid‐bed granulation process are identified. First, the wett...
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Published in | AIChE journal Vol. 45; no. 6; pp. 1202 - 1210 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Hoboken
Wiley Subscription Services, Inc., A Wiley Company
01.06.1999
Wiley Subscription Services American Institute of Chemical Engineers |
Subjects | |
Online Access | Get full text |
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Summary: | The novel technique of spraying binder liquid in pulses of short duration on a bubbling fluidized bed was used to study the effect liquid distribution, mixing, and relative humidity has on granule growth. Two important mixing zones in the fluid‐bed granulation process are identified. First, the wetting zone, where the spraying rate relative to the surface renewal rate determines the wetting of the granules and powder. The surface renewal has to be sufficient to prevent overwetting of the surface, which would result in defluidization of the bed. Second, the bulk zone, where the turnover rate of granules relative to the drying rate may determine the secondary growth rate of granules. The granule growth is influenced by the adsorption of moisture on the fluidized particles governed by the relative humidity of the interstitial gas, due to enhancement of interparticle forces and reduces the mixing intensity. Spraying with pulses has a great potential for controlling the granulation process. |
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Bibliography: | ArticleID:AIC690450606 istex:C0398140A3319495D2850D23C85719D24C7E444A ark:/67375/WNG-88KMVW5Q-J |
ISSN: | 0001-1541 1547-5905 |
DOI: | 10.1002/aic.690450606 |