What are the characteristics of falling film evaporator

Source：www.wsxsfs.cn Release date： 2024-12-18

Information summary：A falling film evaporator is an efficient heat exchange device mainly used for processes such as concentration and evaporation of solutions. It has the following characteristics: 1. Heat transfer characteristics Efficient heat transfer: The falling film evaporator uses the method of liquid film descent to evaporate, forming a uniform thin film of liquid on the heating surface. In this thi

A falling film evaporator is an efficient heat exchange device mainly used for processes such as concentration and evaporation of solutions. It has the following characteristics:
1. Heat transfer characteristics
Efficient heat transfer: The falling film evaporator uses the method of liquid film descent to evaporate, forming a uniform thin film of liquid on the heating surface. In this thin film state, the contact area between the liquid and the heating surface is large, the heat transfer coefficient is high, and efficient heat transfer can be achieved. For example, in the chemical industry, for the evaporation and concentration of some thermosensitive materials (such as certain pharmaceutical ingredients, food additives, etc.), a falling film evaporator can complete the evaporation process in a shorter time, reduce the heating time of the materials, and lower the risk of damage to thermosensitive materials.
Fully utilizing temperature difference: It can fully utilize the temperature difference between the heating medium and the evaporated material. Due to the good fluidity of the liquid film, heat can be quickly transferred from the heating medium to the liquid film, allowing the evaporator to operate effectively even with small temperature differences. This is very advantageous for processes that require evaporation under low temperature conditions, such as using low-grade thermal energy for evaporation.
2. Evaporation characteristics
Short material residence time: In the falling film evaporator, the material flows down along the tube wall in the form of a thin film, and its residence time in the evaporator is relatively short. This has great advantages for handling materials that are prone to decomposition, denaturation, or scaling. For example, in the process of juice concentration, a short residence time can prevent the loss of nutrients (such as vitamins, natural pigments, etc.) in the juice due to prolonged heating, while also reducing the possibility of scaling of sugar and other components in the juice.
High evaporation efficiency: The evaporation process occurs on the surface of the liquid film, and as the film descends, the solvent continuously evaporates, and the solute concentration gradually increases. This continuous evaporation method results in higher evaporation efficiency. In industrial wastewater treatment, the falling film evaporator can quickly evaporate the water in the wastewater, achieve concentration of the wastewater, reduce the volume of the wastewater, and facilitate further treatment of the concentrated wastewater.
3. Operational characteristics
Easy to operate and control: The operation of the falling film evaporator is relatively simple. By adjusting parameters such as feed flow rate, temperature and flow rate of heating medium, the evaporation process can be easily controlled. For example, in dairy processing, operators can adjust the feed rate and heating intensity of the evaporator according to the concentration requirements of the product, to achieve correct concentration of dairy products such as milk.
It can adapt to various materials: it can handle materials with different properties, including solutions, colloids, emulsions, etc. It has wide applications in many industries such as pharmaceuticals, food, and chemicals. For example, in the pharmaceutical industry, it can be used for the concentration of traditional Chinese medicine extracts; In the chemical industry, it can be used for the concentration of various chemical solutions such as ammonium sulfate solution, sodium hydroxide solution, etc.
4. Structural characteristics
Compact structural design: The structure of a falling film evaporator is usually relatively compact, consisting of main components such as a heating chamber, an evaporation chamber, and a distributor. This compact structure makes the equipment occupy less space and can save space in factory layout. Meanwhile, the tight connections between various components are conducive to improving the overall performance of the equipment.
Good anti scaling performance: Due to the thin film flow of materials in the evaporator, the possibility of scaling is relatively low compared to other evaporators (such as coil evaporators). Moreover, some falling film evaporators are equipped with special anti scaling devices, such as regular spray cleaning systems or ultrasonic anti scaling devices, to further reduce the occurrence of scaling and lower equipment maintenance costs.

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