Q12. Granulation Spray granulation is used in a pharmaceutical production process. Under normal condition, the process is capable of process 150 kg of dry powder with a volume of 600 L per batch. During normal operation, the mixture is stirred at 90 rpm and the water is added at a flowrate of 2L/min from a spray nozzle producing an average drop size of 400 um. Due to an incorrect setting, the actual flow rate in an atypical batch was 3.5 L/min and the drop size was 250 um. The spray width and powder surface velocity were unaffected and remained constant at 40 cm and 60 cm/s. Calculate the dimensionless spray flux (a) and fraction of surface wetted (f wer) for the normal and atypical batch. Under these two operation conditions, what will happen to the granulate size? (hint: you may evaluate the nuclei fraction fi using the equation giving in lecture note) 5. Granulation: use liquid to create large particles from small particles (i)wetting and nucleation; 3Q Assess nuclei size distribution: Dimensionless spray flux: Ya 2v w dd Fraction of surface wetted: fwet = 1 - exp(-Y.) (ii) Consolidation Fraction of nuclei f, formed by n drop: fn = exp(-440)| (n-1)! Kinetic control, related with material properties (deformation) (iii) Attrition and breakage : ([cate] =