Challenge
Starch grains are fine and sticky when wet. Drying had to reach the target moisture without letting the discharge temperature rise too high, since bagging warm product causes moisture regain and caking. The customer also required uniform final moisture and a smooth handover to the bagging stage.
Solution
A flash airflow dryer was used, with hot air contacting the material instantaneously and dwell time in seconds, so the discharge temperature stays low. The drying tube size and air volume were configured for about five tonnes per day, and the inlet temperature and air volume were tuned at the trial run to hold the moisture steadily at about 13%.
Result
The final moisture held steadily at about 13%, the discharge temperature was close to ambient, the dried product could be bagged directly, and the daily output met the requirement of about five tonnes.
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.
View all FAQs →