Falling film evaporator vs rising film evaporator

What is a falling film evaporator used for?

  Falling film evaporator is widely used in many fields, including industrial factory, chemical engineering, petroleum and other fields. Falling film evaporator has a high efficiency on the separation of substances, so it is used on milk, glucose, starch, pharmaceutical, chemical, biological engineering, environmental engineering, waste liquid recovery and so on.

Falling film evaporator
Falling film evaporator

How does a falling film evaporator work?

  In falling film evaporator equipment, sample materials will be added from the top of falling film evaporator. Then the materials will be divided into thin films, in order to get heated and evaporated more easily. The heating temperature will be set on the boiling point of substance’s boiling point, which is about to get evaporated. After evaporating the substance, the mixture and substance will be separated.

  Rising film evaporator is upright mounted fixed tube plate heat exchanger. It is suitable for processing heat-sensitive substances with large evaporation volume and susceptible to thermal decomposition and foam-dependent substances. Falling film evaporator is a separation device that is specially suitable for the heat sensitive substances. Falling film evaporator and rising film evaporator both increase heat transfer coefficient through flow in film, but their reasons for forming films are different.

The difference between falling film evaporator and rising film evaporator

  Falling film evaporator and rising film evaporator are both to separate, concentrate or extract substances from mixtures, but there are still some differences between them:

  1. Reasons for forming films. The reason for forming films of falling film evaporator is through gravity. There are falling film distributor installed in the evaporator, in order to make the materials be distributed evenly in the tubes. And rising film evaporator has a high vapor velocity, which makes the liquid rise as a film along the tube wall.

  2. Falling film evaporator is suitable for the situations with low evaporation, while rising film evaporator is suitable for the situations with high evaporation. For example, in some equipment with two-stage evaporation, rising film evaporator is always used for the first stage evaporation and falling film evaporator is always used for the second stage evaporation.

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