Challenge
The moisture content of the pellets was uneven, and conventional drying left them dry on the surface but wet inside. That difference directly affected the subsequent screening and packing stages and also caused moisture regain and caking in storage.
Solution
A flash airflow drying approach extended the effective contact time between the material and the hot air so that moisture in the core and on the surface fell together. The hot air temperature curve was adjusted to avoid over-drying the surface while moisture remained inside.
Result
The final moisture content became uniform, the dry-surface-wet-core problem was resolved, and screening and packing followed smoothly.
Equipment in this case
Flash Airflow Dryer
Capacity varies with operating conditions and is confirmed by a trial run; parameters fixed by machine size, such as air volume, can be stated precisely.
Related questions
Flash airflow dryer or rotary dryer: which one?
The two have different structures and suit different duties:
Flash airflow dryer
It dewaters through brief contact between high-temperature air and the material. Drying is fast, which suits inorganic salts and chemical powders that need rapid dewatering. Sizes are Φ220, Φ280, Φ325, Φ400, Φ500 and Φ600.
Rotary dryer
The rotating drum tumbles the material for more even heating. It suits sawdust, plastic pellets and flake materials that do not break up while tumbling.
How to decide
Look at the material form and whether it is sticky. Powders and fast-dewatering duties point to flash airflow; granular or flake materials needing even heating point to rotary. The moisture content and target final moisture still have to be considered.
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