A falling film evaporator (FFE) is a form of vertically oriented shell and tube (S&T) heat exchanger used to separate two or more liquids with different boiling points.

Two compartments are housed in a shell and tube heat exchanger. Its most fundamental function is to put a heating or cooling fluid, referred to as the media, into indirect but close contact with a product fluid, referred to as the process fluid. The shell and tube heat exchanger exchanges energy as heat between the media and the process fluids. In an S&T heat exchanger, the hotter media transfers energy to evaporate a process fluid component.

In the case of falling film evaporators, the heating medium cycles through the shell side of the S&T heat exchanger. The evaporator receives the process fluid on its tube side. While, the heating medium vaporizes a portion of the product, transferring energy into the product.

Advantages of Falling Film Evaporators

• Efficient Heat Transfer: The thin film of liquid ensures rapid heat transfer, making the process highly efficient.
• Low Residence Time: The liquid spends minimal time in the heated tubes, reducing the risk of thermal degradation of heat-sensitive materials.
• Energy Efficiency: The use of vacuum lowers the boiling point, reducing the energy required for evaporation.
• Scalability: Falling film evaporators can be scaled up for large industrial applications while maintaining efficiency.
• Flexibility: Can handle a wide range of liquids, including those with high viscosities or containing suspended solids.

Applications

1. Food and Beverage Industry:

• Concentration of fruit juices, dairy products, and other liquid foods.
• Preservation of nutritional content and flavor by minimizing heat exposure.

2. Pharmaceutical Industry:

• Concentration of active ingredients in drug formulations.
• Processing of heat-sensitive compounds without degradation.

3. Chemical Industry:

• Concentration of chemicals and solvents.
• Recovery of valuable components from waste streams.

4. Wastewater Treatment:

• Concentration of waste streams to reduce volume.
• Recovery of water and other reusable materials.

5. Desalination:

• Concentration of saline water for salt recovery or further treatment