The key of drying the liquid

The key to drying the liquid is not necessarily the evaporation in water or solvent, but the formation of powder.

The usual method of drying liquid is Spray Dryer. However, the purpose is not necessarily evaporation in water or solvent, but the formation of powder.

Like all drying, spray drying is a mass transfer phenomenon. The concentration gradient on the gas-liquid interface and the surface area of the gas-liquid interface are very important. The former uses dry air to make the concentration gradient larger. Disperse the liquid into small droplets to make the latter larger.

Spray drying is usually carried out in a whirlwind container. The liquid enters the cyclone through a nozzle called the atomizer. The rotating or pressure device atomizes it into very small droplets.

Dry air is forced into contact with fine droplets, which have a high surface area to volume ratio. The additional surface area enhances the evaporation process and the powder precipitates rapidly.

Depending on the application, the air and liquid flow configurations are arranged in many different ways. Patterns are usually cocurrent or countercurrent, but even so, each theme changes. The exact configuration needs to be carefully selected according to the application type.