When dry quickly at high speed wet material, deviation of the moisture content and temperature of the material inside will increase.
As a result, the critical moisture content is increased, it may cause cracks.
When it comes to the state of “evaporation rate of <surface moisture transfer rate of the material inside”, only the surface is dry while containing a lot of water inside the material, critical moisture content will increase.
Therefore, it is also important to shorten the preheating period of Ⅰ period.
The Ⅱ period changes with a liquefied water transfer coefficient.
The Ⅲ period and the Ⅳ period change with a steamy diffusion coefficient.
Move to the liquid rather than move the vaporized is more effective molecular weight of water.
Process design must use ingenuity to reduce the critical moisture content.