How to choose a drying bucket?(Moisture content of raw materials)

What is your raw material?
What is the initial moisture content?
What is the residual moisture content?
What is the required output?
Initial moisture content: the moisture content of the raw material before it is dried.
Residual moisture content: the moisture content required to be reached after the raw material is dried.
Let’s first understand the concepts of water absorption rate, equilibrium water absorption rate, and saturated water absorption rate.
Water absorption: refers to the ability of plastic to absorb water under standard atmospheric pressure.
Equilibrium water absorption: the amount of water absorbed by the material when the amount of absorbed water is equal to the amount of volatile water.
Saturated water absorption: refers to the maximum absorption.
The water absorption of plastic is determined by the number and size of the voids, the way the particles are arranged with each other, whether there are polar groups in the main chain, and the water resistance of the plastic.
Different materials have different water absorption rates.
For example: the equilibrium water absorption rate of PA 6 is 3.5%, and the saturated water absorption rate is about 10%.
      The equilibrium water absorption rate of PC is 0.15%, and the saturated water absorption rate is 1%.
(These data can only be used as a reference, because the materials actually used have been modified and have additives, and the water absorption rate is also different)
Example 1: Different initial moisture content, the same residual moisture content after drying is required.
Raw material: PA6
Sample 1: Initial moisture content: 0.1%, residual moisture content required: 0.05%, then the drying time may take 3 hours.
Sample 2: Initial moisture content: 0.3%, residual moisture content required: 0.05%, then the drying time may take 6 hours.
Sample 3: Initial moisture content: 3.5%. It is recommended to pre-dry before using the dehumidifier, otherwise it will affect the service life of the dehumidifier molecular sieve and affect the drying effect.
(It’s like washing a piece of clothing. If it is not wrung out, it may take a day to dry. If it is spun in a washing machine, it may only take half a day to dry.)

Example 2: The initial moisture content is the same, but the residual moisture content after drying is different.
Raw material: PC
Sample 1: Initial moisture content: 0.1%, required residual moisture content: 0.05%. Drying time is about 3 hours.
Sample 2: Initial moisture content: 0.1%, required residual moisture content: 0.02%, drying time is about 4 hours.
(Although they are all PC materials, they produce different products and have different processes, so the required residual moisture content is also different.)

It can be seen from this that if the output requirements are certain, if the initial moisture content and residual moisture content are unknown, the barrel may be too large or too small.

If the barrel is too small, the drying effect cannot be achieved, affecting the product quality.
If the barrel is too large, the energy consumption may increase, and the drying time is too long, and the raw materials will also be affected.

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