Scale-of-Agitation Approach Example

To illustrate the actual application of the scale-of-agitation approach to scale-up, the above method was applied to the scale-up of typical injectables solution from 378-L pilot batch to a 3780-L production-size batch. The example product is a Newtonian fluid with density of 1.018 g/cm and a viscosity of 0.0588 g/cm/sec (5.88 cps). The tank used in the manufacturing of the pilot batch had the following parameters  

The agitation was accomplished with the turbine-type mixer and the largest axial impeller was 40.64 cm. The pilot batch was mixed at 90rpm (1.5/sec). From the initially known data, the D/T ratio was determined. 

Then the value of the impeller Reynolds number was obtained by plugging known values into Equation (5). 

Because the value of the Reynolds number is 2000, Equation (13) is used to obtain the pumping number. The pumping number is inserted into Equation (15) to obtain the effective pumping capacity. 

Knowing the effective pumping capacity of agitation and crosssectional area of the pilot-batch tank, bulk fluid velocity is obtained by using Equation (16). 

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