Falling Film Evaporator Design and Functions
Tube Bundle—The falling film evaporator consists of a bundle of parallel tubes welded together at each end and encased in a jacket. This jacket allows heat transfer fluid to circulate across the outside of the tubes. The design, also known as a shell and tube evaporator, commonly features vertical tube bundles, though horizontal configurations are also possible.
Heat Transfer and Fluid Distribution—In the vertical configuration, the solution to be evaporated is distributed inside the tubes while the heat transfer fluid circulates outside. The distribution is engineered to ensure that only the inside of the tubes contacts the solution, facilitating efficient evaporation.
Vaporization and Condensation—As the solution is heated within the tubes, its components evaporate. The resulting vapor is then directed to a condenser, which condenses it back into a liquid form.
Design Considerations for Efficiency—Falling film evaporators are designed to handle free-flowing extracts that coat the inside of the tubes under gravity without causing blockages, known as fouling. The system’s capacity increases with the surface area of the evaporator, which can be enhanced by increasing the number of tubes or using smaller diameter tubes.
related DISTILLATION equipment
