Rotating granulator

Convolve the synthetic spectrum with the surface velocity field (rotation, granulation) and with the instrumental profile. 

Fig. 19. TVA-type ammoniator—granulator incorporating a pipe cross reactor. 1, ammonia sparger, located at the 4 o clock position 11.4 cm from granulation shell with holes facing the rotating stream 2, phosphoric acid sparger, located to discharge phosphoric acid onto the top and near the center of the rotating bed of materials 3, pipe cross reactor 4, scmbber Hquor distributor, located above the bed in granulator to dribble scmbber Hquor onto bed.

Granules can be precipitated and formed by extmding the viscous reaction mixture through a circular die containing several holes over which a knife blade rotates to cut the strands into granules (91). The granules are simultaneously slurried in dilute acetic acid to harden the particles for further washing. 

Various methods are used for evaluatiag the quaflty, ie, physical strength and ensyme dust formation, of the granulate. In the elutriation process, a sample of product is fluidised ia a glass tube with a perforated bottom plate for 40 miautes. Dust from the sample is collected oa a filter and the ensyme activity measured. An acceptable dust level is when less than 5—10 ppm of the activity of the sample has been collected. In the so-called Heubach method, 20 g of granulate is elutriated. During the elutriation, four steel balls are rotated ia the bed ia order to evaluate the impact of attritioa oa the dust release of the ensyme. The dust is collected oa a filter and measured. The acceptable dust level is very low. 

Particle Motion and Scale-Up Veiy little fundamental information is published on centrifugal granulators. Qualitatively, good operation rehes on maintaining a smoothly rotating stable rope of tumbling... 

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