Falling film evaporator

In conventional vertical mounted thin film evaporators or falling film evaporators the product film is running down the heated evaporator wall. The residence time in these vertical evaporators is depending on flow rate and viscosity, and varies between a few seconds and one minute. Depending on the wiper system, the evaporation rate is limited by the low product load at the lower part of the evaporator. In order to increase the residence time of the product in the evaporator or to increase the possible evaporation rate or increase the percent distillate, it makes sense to use horizontal evaporators, so that gravity has less influence on the product stream. In this type of evaporator it is possible to vary the required residence time within wide ranges. In a horizontal thin film evaporator, the product is distributed at the heated evaporator wall by the rotor so that a turbulent circular ring forms at the whole evaporator surface. Loss of film integrity, as it can occur at strongly reduced feedrates in falling film evaporators but also in vertical thin film evaporators, is not possible in horizontal thin film evaporators. Therefore very high evaporation rates and also very high percent distillate splits can be achieved on horizontal thin film evaporators. By increasing the product residence time, horizontal evaporators can also be used to carry out continuous reactions and reactive distillation in the thin and turbulent film at vacuum conditions.

Type : falling film, thin-film
Laboratory/process : laboratory
Other characteristics : automatic