Granulation growth

Han (H3) and Han and Wilenitz (H4) have also presented steady-state models of fertilizer granulators based on population balance on the granules in the process loop operating in the snowballing mode. From the viewpoint of process control some interesting interrelationships between various recycle ratios, crusher speed, crusher product size, and the granule growth rate have been established. 

Several excellent reviews of fluid bed granulation were published by Nienow and coworkers (Nienow, 1983, Nienow and Rowe, 1985 and Nie-now, 1994) in which the operation is described in detail. Heat and mass balances on the system are presented and a granule growth model is proposed. The advantages and disadvantages of the operation are discussed. The present approach differs from the above work by looking at the microscale... 

Figure 12. Mechanisms of granule growth, adapted from Tardos et al. (1991).

As granules grow still further, local Stokes numbers exceed the critical value St or St/St — co (see Fig. 23c), so that granule growth is no longer... 

Figure 35. Granule growth mechanisms for population balance modeling. (From Litster and Ennis, 1994.)...

Kurita, Y. and Sekiguchi, L, Effect of vortex orifice air distributor on granule growth in conical fluidized bed granulation with bottom entry spray, /. Ghent. Eng. Japan, 33 (2000) 57-66. 

Schaefer T, Worts O. Control of fluidized bed granulation V, factors affecting granule growth. Arch Pharm Chem Sci Ed 1978 6 69-82. 

Ouchiyama N, Tanaka T. Physical requisite to appropriate granule growth rate. Ind Eng Chem Proc Des Dev 1982 21 35-37. 

Schaefer, T. and O. Worts, Control of Fluidized Bed Granulation, V. Factors Affecting Granule Growth, Arch. Pharm. Chemi. Sci., Ed. 6, 1978, pp. 69-82. 

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