In a typical wet granulation process, pharmaceutical powders and liquids are mixed into a high shear mixer. These mixers create wet granulations with up to 4-6 inch diameter lumps (100-150 mm).
The Customer Challenge - wet granulation
This customer did not have an in-line sizing mill integrated with the mixer and had to use intermediate drums which would re-compact the wet mass.
The product was manually fed by hand scoop from these drums to an oscillating
granulator with an approximate 1/4 inch square mesh screen.
The oscillator produced a 1/4-inch x 1-inch-long extrusion which was spread onto
trays to facilitate a tray dryer system.
It was taking two to three hours to size reduce a 440 lb (200kg) batch of material with this oscillating granulator. Because the extrusions were dense, yet needed to be dried to a moisture level of 1% or less to ensure proper dry milling – drying was taking too long.
The challenge set to the Quadro Engineering team was to reduce the wet granulation process time and eliminate the need to store the product in drums prior to final size reduction.
The Quadro Comil® Solution
The Quadro® Comil® was plug-fed directly from the discharge port of the mixer/granulator with no intermediate handling involved. The Comil® discharged the 440 lb (200kg) batch in as little as 5 to 10 minutes depending on the mixer/granulator’s rate of discharge.
When comparing particles produced from the oscillator and the Comil®, it was obvious that the homogeneously dispersed wet mass from the Comil® was drying faster and more evenly. The oscillating granulator had been producing compressed extrusions whilst the Comil® could now produce smaller uncompressed, homogeneous particles with a high surface area.
This resulted in higher quality drying, as particles are now more uniformly dried. Subsequent dry sizing requires less intensity as there are fewer coarse particles to reduce (this results in lower heat and dust creation).
The Results
The Quadro® Comil® discharged at a rate of 5,000 lb/hr (22,000 kg/hr), compared to an oscillating granulator at at only 200 lb/hr (91 kg/hr). The Comil® could be connected to and plug fed directly from the discharge port of the granulator, whereas the oscillator had required a consistent manual feed.
The Comil® produces uniform particles with a subsequently increased surface area. These particles provide for a much more efficient drying operation than the extrusions produced by the oscillator.
(Ref: AP4R1 Wet Granulation)
