Spray drying is a method of producing a dry powder from a liquid or slurry by rapidly drying with a hot gas. This is the preferred method of drying of many thermally-sensitive materials such as foods and pharmaceuticals.
We use atomizer to disperse the liquid or slurry into a controlled drop size spray. Depending on the process needs, drop sizes from 10 to 500 µm can be achieved with the appropriate choices. The most common applications are in the 100 to 200 µm diameter range. The dry powder is often free-flowing.
Spray dryers can dry a product very quickly compared to other methods of drying.
They also turn a solution or slurry into a dried powder in a single step.
The application of the spray drying encapsulation technique is to prepare “dehydrated” powders of substances which do not have any water to dehydrate. Thermal degradation of products can be overcome by using lower operating temperatures and larger chamber sizes for increased residence times.
Spray drying, the choice dehydration method for the food and pharmaceutical industries, employs an atomizer and a stream of hot gas to produce dry powders, granules or agglomerates from a liquid or slurry. The atomizer disperses liquid feed into fine droplets from which the liquid evaporates, leaving behind solids. Products dried using this process include powdered milk, cake mix, instant coffee, detergent, dyestuff, ceramic powder and yeast extract.
Spray drying achieves below advantages against traditional drying techniques such as:-