Drying principle of chlorinated polyethylene

The wet fraction exists in the solid phase in the form of loose chemical combination or in the form of liquid solution, or in the fine structure of solid hair. The vapor pressure of the liquid is lower than that of the pure liquid, which is called the combined water; the free wet fraction on the surface is called the non combined water.

Due to the existence of polar genes in the macromolecular structure of chlorinated polyethylene (CPE) and the very loose structure of its powder, there will be not only "non binding water" but also "binding water" in its wet powder. It is more difficult to dry it to a moisture content of no more than 0.3% (wet basis) (at this time, it is regarded as qualified for drying).

For this reason, we choose hot air as the heat transfer medium for (fluidization) drying. The particles containing water contact with hot air flow. Because the water vapor pressure on the surface is greater than the water vapor pressure in hot air, the water vapor diffuses from the particle surface of the material to hot air, and is taken away by the hot air with constant flow and renewal.

With the continuous vaporization of the moisture on the surface of the material, the moisture inside the material particles is higher than its surface moisture, forming a moisture gradient, then the moisture inside the particles continuously diffuses to the surface until the equilibrium moisture of the material is reached.