Scale Granulator Vessel

Scale Granulator Vessel The local variables of moisture and shear level vary with volume element, or position in the granulator, which leads to the kinetics of nucleation, growth, consolidation, and breakage being dependent on position in the vessel, leading to a scale of scrutiny of fne vessel size. As shown in Fig. 21-147, moisture levels and drop phase concentration and nucleation will be high at position... 

M. Uliveri, M. Eli, and R. Bianchini (unpublished data) also attempted a scale-up in a V-shaped granulator. The laboratory vessel was a 0.056 m (2ft ) model and the scale-up vessel was a 0.283 m (10 ft ). They found it was necessary to increase the batch size 1.2 times over the direct 10 2 ratio, that the total liquid was 82% of direct scale-up, and the granules were slightly larger in the scale-up vessel. 

Dimensionless numbers, such as Reynolds and Froude numbers, are frequently used to describe mixing processes. Chemical engineers are routinely concerned with problems of water-air or fluid mixing in vessels equipped with turbine stirrers where scale-up factors can be up to 1 70 (3). This approach has been applied to pharmaceutical granulation since the early work of Hans Leuenberger in 1982 (4). 

Scale-up with vacuum dryers is relatively easy and straightforward. Each vessel has a characteristic surface to volume ratio that identifies the quantity of heated surface available and the working volume of the granules in the vessel. The drying time in a laboratory vessel may be used to determine drying time in a larger vessel through use of Equation (28) ... 

Equation (21-139) reflects the evolution of granule size distribution for a particular volume element. When integrating this equation over the entire vessel, one is able to predict the granule-size distribution vs. time and position within the granulator. Lastly, it is important to understand the complexities of scaling rate processes on a local level to overall growth rate of the granulator. If such considerations are not... 

Design variations include different chamber configurations for use in coating tablettes, coarse granules, or fine particles (Fig. 10.29). For scale-up, the outer vessel diam-... 

Design variations include different chamber configurations for use in coating tablets, coarse granules, or fine particles (Fig. 6.2-85). For scale-up, the outer vessel diameter and the number (rather than the size) of inner tubes increase. Each tube features its own gas distributor and spray nozzle and is essentially identical with that in the test equipment that was used during development work [B.97]. 

The matching Froude numbers for different size granulators provide the possibility of linear scale-up. However, some precautions are still needed for the geometric dissimilarity of mixing bowl vessels, and the shape of the impellers in the granulators of different types and scales. 

Another scale-up attempt in a V-shaped granulator involved a 2 and 57 L vessel (15). The author used a cumulative torque to mass ratio as a means of relating the process in both vessels. A separate, individual method is also provided for scaJing-up the liquid addition time. 

---