Thin Film Drying Plants
A Thin Film Dryer is a special type of a wiped film evaporator. A thin film dryer consists of a horizontal or vertical shell with nozzles for products, vapours and heating medium as well as a special rotor system.
The product is continuously distributed over the circumference of the heating wall. The wall contact is continually renewed by special wiper elements and the product film is transported to the residence section at the same time by gravity (vertical type) or wiper system (horizontal type).
The wipers do not touching the heating shell (defined gap), however they prevent fouling on heating surface, which can often occur during evaporation of liquids with solids. Due to the special design it is possible to dry up liquid feed product to powder form. The dryers, both individually (vertical / horizontal) and combined (as pre-dryer in the vertical and as after-dryer in the horizontal) can be used.
Outstanding features of drying according to the thin film evaporator principle:
- Less pressure drop
- Gentle product handling and purification
- Gentle evaporation through short residence time and highly efficient agitation of the film
- Mechanical purification prevents deposits on the heating surface
- Less need for maintenance through sophisticated bearings and sealings
Wiped-film dryers are successfully operated in the chemical, pharmaceutical and food industries for the production of:
- Chemical products
- Chemical sludges (process sludges, industrial sludges and municipal sludges)
- Solvents of supensions
- Wet solids
- Salted solutions
- Fatty acid industrye
- Specialty chemicals for solvent recovery from salt solutions