Vobis Multiple Effect Falling Film Evaporators enable efficient production of client products from hundreds to tens of thousands of liters per hour. All of our Falling Film Evaporators work via the same general process: raw material is fed through the proprietary optimized distribution system, to the top of the heating tubes, and then evenly distributed on the insides of the tubes’ walls. A thin, generally turbulent flow of the liquid film spirals down the inside of the tubes, coating the entire surface for excellent heat transfer. Vapor and liquid are separated while entrainment is minimized.
Falling Film Evaporators are compatible with heat-sensitive products with relatively low viscosity; they have a short residence time in the tubes, and typically evaporate under vacuum to lower the volatile component boiling point. The short residence time minimizes heat exposure, and operation under vacuum allows for lower temperature evaporation, ideal for heat sensitive liquids. High evaporation loads can also be readily accommodated; when necessary, for fully wetting the complete lenght of the tubes' wall surfaces, recycling of liquid can be implemented.
Efficient operation of our falling film evaporators implemented for temperature-sensitive products is achieved through several features. Optimized liquid feed distribution to our falling film tubes help create high heat transfer coefficients. Low pressure drop helps to minimize fouling. Automated PLC-driven process controls for variables including: temperature, vacuum, and feed rate, insure accurate control and reproducible results. The minimized material inventory requirement provides for flexible operation, quick start-up, and easy changeover among different products. Falling film evaporators can also be utilized for liquids with relatively low viscosity without complication.
Vobis multiple effect falling film evaporators are often large and always energy-efficient systems – including implementation of multiple effects, and incorporating thermal vapor compression, or mechanical vapor compression. For pilot scale falling film systems please see our pilotevaporators website.