Falling film evaporator

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The difference between a falling-film evaporator and a rising-film evaporator is that the feed liquid is added from the top of the heating tube. Under the force of its own gravity, the solution flows down along the inner wall of the tube in a film-like form and is evaporated to concentrate. The vapor-liquid mixture enters the separation chamber from the bottom of the heating tube; after vapor-liquid separation, the liquid product is discharged from the bottom of the separator. To enable the solution to form a uniform film on the wall, a liquid film distributor must be installed at the top of each heating tube. There are various types of film applicators. Falling film evaporators can evaporate solutions with high concentrations, and they are also suitable for materials with high viscosity. However, it is not suitable for solutions that are prone to crystallization or scaling. Furthermore, since the liquid film is difficult to distribute evenly inside the tube, its heat transfer coefficient is lower compared to rising film evaporators.