April 24, 2023
Keyword：rotary flash dryer、drying equipment
Spin flash dryer is a drying process that is widely used in the field of powder drying in China. It has the advantages of strong heat transfer, high production intensity, short drying time and continuous drying.
Design Points:
1. Determination of the drying room
In practical applications, we use the following two methods:
1. Evaporation intensity method, this method is an indirect method of volume heating method. It is calculated by certain experimental data and is often used in industrial design. The evaporation intensity method calculates the volume of the drying chamber according to the amount of evaporated water and the evaporation intensity, and then calculates the effective height according to the relationship between the diameter and the height.
2. Another method is to calculate the required air consumption through material balance calculation and heat balance calculation, and then determine the diameter of the dryer according to the air speed range.
2. The height and particle size of the dryer
The drying process of the flash dryer mainly relies on the hot air generated by heating from the heat source and enters the drying chamber through the annular gap in a tangential direction. During this period, the material is fully dehydrated and dried. It can be seen from this that the height of the flash dryer is determined by the distance that the hot air needs to pass, and the distance is determined by the initial moisture and final moisture of the material and the heat provided by the heat source. Please refer to the specific formula and parameters when designing. Equipment Design Manual. In addition, when studying the fluid motion of smaller particles under the action of centrifugal force field, the influence of gravity is very small and can be ignored.
3. Industry application
The operating conditions of some rotary flash dryers. The upper part of the drying chamber is provided with a grading ring, which is mainly used to separate the materials with larger particles or not dried from the qualified products. Blocking in the drying chamber can effectively ensure product particle size and moisture requirements. Replacing grading rings with different diameters can meet product particle size requirements. Cold air protection is provided at the hot air inlet at the bottom of the cone to prevent overheating and deterioration of materials in contact with high temperature air. The drying system is closed, and it operates under a slight negative pressure, so that the dust does not leak out, which protects the production environment and is safe and hygienic.
