The heat exchange in flash drying equipment mainly includes convective heat transfer between the air flow and the particles, and conduction heat transfer between the cylinder wall and the particles. The essence of the drying process is the process of diffusion of moisture from the material.
In a rotary flash dryer, a high-temperature air stream enters the cylinder in a tangential direction, creating a rotational motion. This rotational airflow not only increases the velocity of the airflow around the particles, but also reduces the temperature of the medium around the particles. This makes it easier for moisture to evaporate from the surface of the particles, increasing the rate of external diffusion.
The high-temperature air flow impacts the particles or wet materials located in the lower part of the cylinder at high speed, and at the same time, the stirring action of the stirring blades makes the particles be broken, reduces the particle size, thereby reducing the length of the internal capillary, strengthens the effect of internal diffusion, and reduces the resistance of internal diffusion. These crushed particles are repeatedly crushed in a cycle of high temperature and high agitation intensity in the lower part of the cylinder, further intensifying the internal diffusion process.
Eliminating material agglomeration is also a powerful measure to promote internal diffusion, and improves drying efficiency by enhancing the evaporation of particle moisture. This drying method is suitable for handling large-scale materials such as powdery, granular or fibrous materials. Through reasonable heat exchange and material crushing, high-quality dry products can be obtained.