A falling film evaporator is one of the most effective evaporators and well-received in many industries. So what is a falling film evaporator exactly? The following part will help you have a better understanding of a falling film evaporator.
What is a Falling Film Evaporator?
A falling film evaporator refers to a concentration and evaporation device used in industries. It is applicable for the concentration and evaporation of water, organic solvents and solutions in the pharmaceutical, food, chemical, light industries and other industries, and it is especially suitable for heat sensitive materials and materials with higher concentration and higher viscosity. The equipment is continuously operated under vacuum and low temperature conditions, with high evaporation capacity, energy conservation, low operating cost. It can ensure that the material is invariable during the evaporation.
Classifications of Falling Film Evaporators
There are several kinds of falling film evaporators: single effect of falling film evaporator, double effect of falling film evaporator, three effect of falling film evaporator, four effect of falling film evaporator, five effect of falling film evaporator, six effect of falling film evaporator. It is suitable for milk, glucose, xylose, pharmaceutical, chemical, bioengineering, environmental protection engineering Low-temperature concentration in industries such as waste liquid recovery.
Characteristics of Falling Film Evaporators
The characteristics of falling film evaporators are as follows:
- Since the solution flows in a single-pass type evaporator, the heat transfer coefficient is high, the residence time is short, and the material is not easily deteriorated. It is suitable for processing heat sensitive materials.
- The liquid of the falling film evaporator is added from the top of the evaporator, and descends along the wall of the tube under the action of gravity. Sample will be evaporated and concentrated during this process, and a concentrated liquid is obtained at the bottom. The falling film evaporator can evaporate materials with higher concentration and higher viscosity.
- Falling film evaporator is suitable for evaporation and concentration of foaming materials.
Construction and Working of a Falling Film Evaporator
Due to the need of substances’ extraction and concentration in industrial field, there are so many types evaporators in marketing. Even though there are so many different types of evaporators, their construction are very similar. Generally, the construction of evaporators includes a heat exchanger to heat the sample substances, a condenser to condensate the extracted substances, a separator to separate the mixed liquid and extracted substances, and a vacuum pump to provide a vacuum environment for the whole operating equipment.
The working of falling film evaporators can be described as follows. The liquid is added to the upper tube of the heating chamber of the falling film evaporator. Through the liquid distribution and film forming device, it is evenly distributed into the heat exchange tubes. Under the action of gravity and vacuum induction and air flow, it forms a uniform film from the top to the bottom. During the flow, it is heated and vaporized by the shell-side heating medium. The generated steam and the liquid phase enter the separation chamber of the evaporator. The vapor-liquid is sufficiently separated, and the steam enters the condenser for condensation (single-effect operation) or enters the next-effect evaporator. The medium is heated to achieve multi-effect operation, and the liquid phase is discharged from the separation chamber.