Granulation dispersive growth

In practice, so-called overspray occurs this characterizes the non-deposited liquid drops. In the model, a factor kos considers the overspray, as a ratio of the mass flux of the overspray and the injected solid mass flux. The efficiency of the separator (filter, cyclone) is considered by a factor ksep, which describes the ratio of the re-fed mass flux to the granulator to the fed mass flux into the separator. The factor kgrowth describes the ratio of the mass flux which comes from the separator and is used for the layering and growth (continuous phase) and the mass flux which comes from the separator (dust) and is used as new internal seeds (disperse phase). 

Tattiyakul, J. 1997. Studies on granule growth kinetics and characteristics of tapioca starch dispersions using particle size analysis and Aeological methods. M. S. Thesis, Cornell University, Ithaca, NY. 

Figure 4-20 Master Curve of Reduced Complex Viscosity = t] ((olcor) Data Obtained on the 8% Com Starch Dispersion at Several Heating Rates and Frequencies (Yang and Rao, 1998). The letters A-D refer to stages in granule growth.

Spray distribution generally has a large effect in fluid beds, but in many cases, a small effect in mixers. In fact, fluid-bed granulation is only practical for wettable powders with short drop penetration time, since otherwise defluidization of the bed would be promoted to local pooling of fluid. Mechanical dispersion counteracts this in mixers. There may be a benefit, however, to slowing the spray rate in mixers for formulation with inductive growth behavior, as this will minimize the lag between spray and growai, as discussed previously. 

They can process plastic, sticky materials and can spread viscous binders. That is, they can operate in the mechanical dispersion regime of wetting and the deformable regime of growth (see Granulation Rate Processes ). 

In this type of polymerization the monomer is dispersed in a liquid (usually water) by vigorous stirring and by the addition of stabilizers such as methyl cellulose. A monomer-soluble initiator is added in order to initiate chain-growth polymerization. Reaction heat is efficiently dispersed by the aqueous medium. The polymer is obtained in the form of granules or beads, which may be dried and packed/bagges directly for shipment. Refer to Bulk Polymerization Emulsion Polymerization, and Solution Polymerization. 

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