Boiling drying method in biological industry
Principle: It is the use of fluidization technology, that is, the use of hot air to fluidize and boil the granular material on the orifice plate, so that the water is rapidly vaporized to achieve the purpose of drying. During drying, the vapor flow rate is equal to the sedimentation rate of the particles. When the pressure drop and the mass of the flow layer per unit area reach equilibrium, the particles are suspended in the gas and rotate freely in the flow layer, and the flow layer seems to be boiling. This state is relatively stable fluidization.
Features: High heat and mass transfer efficiency. Due to the use of fluidization technology, the gas and solid two phases are in close contact. Although the heat transfer coefficient of the gas-solid two phases is not large, due to the small granularity and large contact surface area, the volumetric drying intensity is the largest of all dryers. This requires a significant reduction in bed volume. It is better than airflow drying in terms of heat transfer, mass transfer, volumetric drying intensity, thermal efficiency, etc. The drying temperature is uniform and easy to control. Drying and cooling can be carried out continuously, and drying and grading can be carried out at the same time, which is conducive to continuity and automation. Due to the large volumetric drying intensity, the equipment is compact, the floor area is small, the structure is simple, the equipment capacity is high, and the power consumption is low. However, when the material is continuously operated, the residence time in the dryer varies, and the drying degree is not uniform enough, which has a wear effect on the crystalline material.
