In the process of operation, the airflow dryer mainly uses its high-speed flowing hot air flow to make the wet starch suspended therein, and has advantages such as high heat transfer coefficient and large heat transfer area during operation, and the drying time of the airflow dryer. Short and other characteristics.
The airflow dryer is also referred to as an instantaneous drying apparatus to a certain extent. When it is used, it is mainly the application of dilute phase transportation in the stationary fluidization in the aspect of drying. In the process of use, the heating medium can be directly contacted with the fixed particles to be dried, so that the dry solid particles are suspended in the fluid, thus the two phases have a large contact area, strengthen the heat and mass transfer process, and are widely used in bulk Drying unit operation of the material.
The wet material of the air dryer is directly added into the vertical tube by the feeder during the operation. During the operation, the air is effectively blown into the fin heater through the blower, and heated to a certain temperature and blown into the vertical tube. The velocity in the tube is determined by the size and density of the wet particles, and is generally greater than the sedimentation velocity of the particles (approximately 10 to 20 meters/second).
When the air dryer is in operation, its dried particles will be directly brought out by the strong air flow, which will be sent directly to two parallel cyclone separators, and be effectively sent through the screw conveyor when used. The exhaust is vented via a bag filter. Because of the short residence time, it is often necessary to use two or more cascaded processes for some products.
In the air dryer, the hot air is entrained with the back-dried material particles and the direction of the tangential line enters into the cyclone dryer, and a rotating motion is generated along the hot wall, so that the material particles are in a state of suspended rotation and dried. The wall may be provided with a steam jacket as required. The drying process is greatly strengthened.
The air dryer will be crushed to a certain extent due to the impact of its particles and the wall. When it is used, the air-solid contact area increases and the drying process is also strengthened. It is particularly suitable for heat-sensitive bulk materials that are highly hydrophobic and are not afraid of crushing. However, it is not suitable for materials with high water content, large viscosity, low melting point, easy sublimation and explosion, and easy static effect.