Major concerns in granulator processes include feed rate of liquid, operator control, and overgranulation
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Granulator Process Concerns

Major concerns in granulator processes include:

Feed Rate of Granulator Liquid
As particles grow in the granulator, the amount of liquid is increased to produce a tighter size distribution. The amount of liquid added to the granulator also makes the granules harder and larger, therefore decreasing the amount of finer granules. Normally, knowing the amount of liquid in the granulator is crucial in the granulation process in order to obtain the correct particle size.

With real time size analyzers like the Parsum or the Insitec, the particle size, is known instantaneously, therefore, knowledge of the liquid quantity in the granulator becomes much less critical.

Operator Control
Fluid bed granulator processes are very complex, involving a number of different parameters that affect the final product. Material that is too coarse must be either milled or re-dispersed, depending on the process, and fed together with the fines and the fresh material back into the granulator bed. A certain amount of recycled material is required as new seeds for the granulation process. Some new seeds are produced due to both friction and overspray in the fluidized granulator bed. If there are not enough seed grains, the process becomes unstable. Because of these complicated independent variable, many fluid bed granulator processes are controlled entirely through the experience of the granulator operator. This subjective control can lead to significant yield differences.

With an in-line particle size analyzer, granulator operator variances are reduced substantially. The operator now has a tool that provides them with an accurate size measurement while the granules are being produced.

Overgranulation
The particle size of the granulate is determined by the quantity and feeding rate of granulator liquid. One major concern in the granulation process is when too much granulating liquid is added. Mean granule size is strongly dependent on the moisture content and liquid saturation of the agglomerate. Excessive wetting can lead to overgranulation. This is less likely to happen when the particle size is continuously known from the in line Parsum analyzer.