The working principle sets the limits
A flash airflow dryer uses hot air to carry the material while dewatering it. Since the material has to travel in the air stream, whether it can be suspended and conveyed steadily is the first question to answer.
How it differs from a conveying-type air route without disintegration
There is a disintegrating device at the bottom of the drying chamber and a classifier ring at the top: wet material is broken up first, then meets the tangential hot air, and only particles of the right size leave with the air stream while coarse particles keep circulating. That is why sticky, paste-like or filter-cake material can also be handled, where a plain conveying air route cannot cope.
How it differs from a conveying-type air route without disintegration
There is a disintegrating device at the bottom of the drying chamber and a classifier ring at the top: wet material is broken up first, then meets the tangential hot air, and only particles of the right size leave with the air stream while coarse particles keep circulating. That is why sticky, paste-like or filter-cake material can also be handled, where a plain conveying air route cannot cope.
Suitable materials
Granular and powdery materials fit best: feed pellets, plastic pellets, inorganic salt powders, starches and fine chemical powders. They do not stick to each other in the air stream and dry relatively evenly.
Where it does not fit
Lumpy and fibrous materials are hard to convey steadily in an air stream. Those are better handled by a rotary or another type.
Parameters to provide
Material name and form, initial moisture content and target final moisture are the basis of the assessment. Capacity varies with conditions and is confirmed by a trial run; air volume can be stated precisely.
References and Standards
- JB/T 10278—2015 Flash dryers[S]. Beijing: China Machine Press, 2015. (in Chinese)
- JB/T 10176—2012 Rotary flash dryer[S]. Beijing: China Machine Press, 2012. (in Chinese)
- Liu G W. Design Handbook of Drying Equipment[M]. Beijing: China Machine Press, 2009. (in Chinese)
- Levy A, Borde I. Pneumatic and flash drying[M]//Mujumdar A S. Handbook of Industrial Drying. 4th ed. Boca Raton: CRC Press, 2014.
- Mujumdar A S. Handbook of Industrial Drying[M]. 4th ed. Boca Raton: CRC Press, 2014.
- Tan T E, Dou M. Principles of Chemical Engineering[M]. 4th ed. Beijing: Chemical Industry Press, 2013. (in Chinese)