Granules spray drying

Anwar SH, Kunz B (2011) The influence of drying methods on the stabilization of fish oil microcapsules Comparison of spray granulation, spray drying, and freeze drying. Journal of Food Engineering 105 367-378. 

Furthermore, the more round granule shape becomes evident of the granules spray dried from co current drying mode. This change will furthermore affect handling and flow properties of the granules. 

Figure C2.11.3. A scanning electron micrograph of tire spherical alumina granules produced by spray drying a ceramic slurry. The granules are comprised of individual alumina particles, sintering additives, and an organic binder.

Sublimation of ice crystals to water vapor under a very high vacuum, about 67 Pa (0.5 mm Hg) or lower, removes the majority of the moisture from the granulated frozen extract particles. Heat input is controlled to assure a maximum product end point temperature below 49°C. Freeze drying takes significantly longer than spray drying and requires a greater capital investment. 

Tn comparing the content of drug extract in the final product, teas in granule form are usually very much inferior to instant teas which arc prepared from spray-dried extracts teas in granular form, in addition to 97 -98% filler and carrier substances often contain only 2-3% dry extract, while in spray-dried products almost ten times as much, viz on average 20%, drug extract is present. 

In many eases the solid assumes the wet-bulb temperature of the gas stream (wet-bulb proteetion), partieularly if the solid is in the form of granules or is spray dried. This is partieularly useful for heat sensitive materials. So, at eonstant drying rate... 

In wet granulation experiments, dried Ti02 particles were fed into the cylindrical air distributor (vessel), then the air distributor rotated and fluidization air was supplied. After a predetermined amount of binder liquid was sprayed, drying of products was conducted. 

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