Due to its inherent design features, it is ideal for thermal treatment of solutions and heat sensitive products, where reduced operating temperatures and vacuum operating pressures are desirable. The typical Agitated Thin Film Evaporator consists of a tubular heat transfer area with an external heating jacket and a fast-revolving, inner rotor with flexible or rigid wiper elements. The driving speed is adapted to the product being handled, its particular specifications and task.
The feed product is evenly distributed by the rotor and its wipers over the heating surface, forming a thin liquid film of uniform thickness. Highly turbulent swirls are produced at the tip of the rotor blades and wipers with intensive mixing and agitation of the product, as it comes into contact with the heating surface. This assures excellent heat transfer combined with constant renewal of the product film and provides an even heating and short residence time of the product through the heated zone.
· Operating pressure from atmosphere down to 1 Ton vacuum
· Operating temperature up to 300 oC
· Good heat conductivity (k-value), even when working with highly viscous and contaminated products
· Minimal thermal stress, thanks to low operating capacity, therefore a short dwell time (10-20 seconds of mean dwell time)
· No dead zone, therefore overheating prevented and perpetual high product quality guaranteed
· Continuous mechanical cleaning of the heating surface prevents incrustations
· High evaporation rates, due to highly turbulent film and large difference in temperature
· Evaporation in one pass, no circulation
· Small film thickness, no hydrostatic height
Mainly used for difficult vaporization and heat exchange processes, especially where products to be handled are highly viscous and conventional plants can no longer meet user demands because heat transfer is insufficient. Due to the liquid film, mechanically generated on the heating surfaces, thin film equipment achieve much better heat transfer rates, even with highly viscous products containing solids.
· To concentrate highly viscous products, polluted liquids, salt solutions, oils, resins, etc
· As a sump evaporator for vacuum rectification columns
· Sludge drainage
· To continuously dry powdery residues
· Heating or cooling of viscous solutions
· Separation of close-boiling compounds
· Recovers additional bottoms product from overhead