The advantages and disadvantages of spray drying
2018-05-16
a) Due to the large surface area of the droplets, the required drying time for the material is very short (in seconds). b) In the high-temperature air stream, the temperature of the surface-wetting material does not exceed the wet-bulb temperature of the drying medium, and the final product temperature is not high due to rapid drying. Therefore, spray drying is particularly suitable for heat-sensitive materials. c) According to the flexibility of spray drying operation, it can meet the quality indicators of various products, such as particle size distribution, product shape, product properties (does not contain dust, fluidity, wettability, instant solubility), product color, and fragrance , taste, biological activity, and moisture content of the final product. d) Simplify the process. The solution can be made directly into a powder product in a drying tower. In addition, spray drying is easy to achieve mechanization and automation, reduce dust flying, and improve the working environment. At the same time, spray drying also has the following disadvantages: (1) When the air temperature is lower than 150°C, the volumetric heat transfer coefficient is low, and the equipment used is large in solution. (2) The separation requirements for gas-solid mixtures are high, and two-stage dust removal is generally required. (3) The thermal efficiency is not high, usually 30%-50% for downstream towers and 50%-75% for counterflow towers.
Share to:
