Spray drying is a particular technique used to remove the moisture content of a material, such as a product, in order to make it easier to handle and store.This process is mainly used in the chemical industry and the food industry, but can also be used in other industries.
The basic principle of spray drying is to atomize a wet material, such as a liquid or suspension, into droplets and then to heat these droplets so that the moisture can evaporate.The atomized wet material is initially fed into the dryer through a spray nozzle. The material is then heated by a hot air stream, and as the material is atomized, the moisture evaporates and a dry product is produced. The dry product is fired from the dryer.
There are many advantages to using a spray drying process. It is a relatively efficient process, since it only takes a few seconds to complete the drying process and it is relatively low energy consuming. It is also a hygienic process, since it is not related to any contact with the material. Also, due to the small size of the droplets, the drying process can be very precise and the prepared powder is homogeneous.
Spray dryers are used for many applications and for a variety of materials. The most common materials that are applied in a spray dryer are milk and fruit juices, pharmaceuticals, chemicals, pigments, and more.
The design of the spray dryer varies depending on the application. Commonly, there are two main types of dryers – rotary and fluidized bed. A rotary dryer is a simple drum-like rotating dryer which does not involve any complex design and is suitable for drying of materials which require simple process control. The most popular among this type is a double cone type. On the other hand, a fluidized bed is a more complex design in which the material is fed into a drying chamber which is flowing with a hot gas. The material is then dried as the gas carries away the moisture content. This is a suitable option for materials which require intensive heat and mass transfer.
To determine which type of dryer to use, it depends on the material to be dried, its feed rate, desired product size, and temperature. The materials that are commonly dried in a spray dryer are pharmaceuticals, chemicals, pigments, and food.
Spray dryers are becoming increasingly popular and are used in many different types of industries due to its ease of use, efficiency, and effectiveness. By choosing the correct type of dryer for the material, the spray dryer can be used to quickly and efficiently dry materials for a variety of applications.
