Agglomerate growth, regions

Fig. 7.3 Average pellet diameter as a function of agglomeration time (measured in drum revolutions). (A) Region of seed (nuclei) formation (B) transition region (C) agglomerate growth region.

Kapur and Fuerstenau (K6) have presented a discrete size model for the growth of the agglomerates by the random coalescence mechanism, which invariably predominates in the nuclei and transition growth regions. The basic postulates of their model are that the granules are well mixed and the collision frequency and the probability of coalescence are independent of size. The concentration of the pellets is more or less fixed by the packing... 

The same applies to crystallizers, in which particle sizes and particle number concentrations not only depend on nucleation and growth from supersaturated mother liquid, but are also affected by shear-dominated agglomeration and by secondary nucleation as a result of particle particle and particle-impeller collisions. Some of the subprocesses involved may be limited to specific and different parts of the vessel e.g., nucleation may be restricted to a flame-like region around the outlet of a feed pipe (Van Leeuwen, 1998). In addition, in... 

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