The falling film evaporator is a process where the liquid material enters the liquid distributor from the top of the evaporator, and is evenly distribute liquid into each heating tube through the liquid distributor. The liquid material flows down the tube wall in a film like form, and is evaporated and vaporized by the heat transferred from the tube wall. When the heat transfer temperature difference is not large, vaporization occurs on the strongly disturbed inner surface of the film, rather than at the interface between the heating tube and the liquid film. Therefore, it is not easy to scale. The generated steam and liquid film flow down together.
The falling film evaporator has the advantages of large heat exchanger absorption, high evaporation intensity, and energy saving. There is a high heat transfer rate under low temperature difference, even if the temperature difference is only 3-4 ℃, it does not affect the operation. Commonly used in multi effect evaporation systems, it can be operated in a single pass through a falling film evaporator or in a cyclic manner. For the evaporation and concentration of dilute solutions, falling film evaporators are often the preferred form.
The falling film evaporator has a short heating time for materials inside the equipment, making it easy to ensure product quality. High heat transfer efficiency, easy to achieve multi effect operation. The operation flexibility of the evaporator is relatively high, and the control requirements are not very strict. Widely used for low concentration efficiency of materials, sugar solutions, milk, and high salt wastewater that do not undergo salt precipitation during the evaporation process.