Precautions for designing flash dryer
1. The flash dryer processes the evaporation intensity of some materials. The volume heating method is the theoretical design method of the flash dryer. However, the most critical volume heating coefficient in this method is difficult to determine, so it lacks operability. The evaporation intensity method is an indirect method of the volumetric heating method. As long as there is a certain amount of experimental data, it can be calculated. It is a method often used in industrial design. The evaporation intensity method calculates the volume of the drying chamber based on the amount of water evaporated and the evaporation intensity, and then calculates the effective height based on the relationship between the diameter and the height.
2. Calculate the required air consumption through material balance and heat balance, and then determine the diameter of the flash dryer according to the air speed range.
3. The hot air from the hot air distributor enters the drying chamber through the annular gap in a tangential direction. The materials in the drying chamber make a spiral rotating upward movement under the action of the hot air blowing and the push of the agitator. When studying the fluid motion of smaller particles under the action of centrifugal force field, the influence of gravity is very small, so it can be ignored.
4. For the operating conditions of some flash dryers, the upper part of the drying chamber is equipped with a grading ring. Its main function is to separate large or undried materials from 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. The hot air inlet at the cone bottom is provided with cold air protection to prevent the material from overheating and deterioration due to contact with high temperature air. The drying system is closed and operated under slight negative pressure to prevent dust from leaking, protect the production environment, and be safe and sanitary.