Why are disc dryers widely used in industries such as pharmaceuticals and light industry?

Disc drying is widely used in the production of pharmaceuticals, light industry, dyes, food, and certain fertilizers. It is particularly suitable for heat-sensitive materials such as milk, pharmaceuticals, and dyes, and occupies an important position in drying technology. The principle of disc dryer is to increase the contact area between the liquid and the gas phase by atomizing the liquid into fine mist in a hot air stream. For example, atomizing 1 cm³ of liquid into 10 μm spherical droplets increases the surface area by six thousand times, which greatly improves the drying speed, allowing the droplets to be dried into powder or fine particles in a very short time (a fraction of a second). The dryer body can be made into two types: vertical cylindrical (tower type) or horizontal (chamber type), with the tower type being more widely used. Compared with the aforementioned drying methods, disc drying has the following advantages:

(1) The drying process is extremely fast in a high-temperature medium, while the surface temperature of the particles is still close to the wet-bulb temperature of the medium. Therefore, the quality of the dried product is good, heat-sensitive materials are not easily deteriorated, and fast-dissolving powder or hollow fine particles can be obtained. (2) The product that meets the requirements can be obtained directly from the slurry liquid, thereby eliminating the need for processes such as evaporation, crystallization, separation and crushing.