Granulation consolidation

FIG. 20-74 Effect of binder viscosity and liquid content on final granule porosity for the drum granulation of 15 im glass baUotini. Decreasing granule porosity corresponds to increasing extent of granule consolidation. [Iveson et al., Powder Tech., 88, 15 (1996). ] With land permission from Elsevier Science SA, Lausanne, Switzerland. 

Iveson, S., Litster, J. D., and Ennis, B. J., Fundamental Studies of Granule Consolidation, 21st Australasian Chem. Engng. Conf, CHEMECA (1994)... 

S. M. Iveson, J. D. Htster, B. J. Ennis, Fundamental studies of granule consolidation - part 1 Effects of binder content and binder viscosity, Powder Technol., 1996, 88,15-20. 

Increasing feed particle size (can be controlled by milling) Requires increase in excess gas velocity Has minimal effect on growth rate Increases in granule consolidation and density Increases growth rate Increases granule consolidation and density... 

The impact of scale on growth and consolidation depends upon the choice of collisional velocity (Table 21-22). Granule consolidation and density likely increase with the maximum peripheral speed, or scale-up by For growth, on the basis of a critical viscous Stokes number... 

To improve upon maintaining swept volume as a scale-up criterion, one must also consider the impact of scale-up on wetting, nucleation, growth, and granule consolidation. To maintain bed moisture with scale-up requires that the sprayed binding fluid increase with the bed volumetric scaling ratio P, or... 

Gas velocity Increases attrition and elutriation rates (major effect) Decreases coalescence for inertial growth Has no effect on coalescence for noninertial growth, unless altering bed moisture through drying Increases granule consolidation and density... 

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