For the shell tube falling film evaporator, the material in the tube process, first of all, is in the temperature difference and gravity double push action is film-like falling flow state, so its heat transfer coefficient is large, can use low temperature difference drive evaporation; Secondly, the holding liquid volume is small, short residence time.
The falling film evaporator is suitable for evaporation and concentration of the following materials:
1. Heat-sensitive materials: Because the heat transfer method of falling film evaporator is indirect heating, so that the material temperature is lower, and at the same time the material stays in the evaporator for a short time, so it can effectively avoid excessive heating and decomposition for heat-sensitive materials.
2. High viscosity, high concentration of materials: because of the liquid material along the wall down to form a thin film, so even viscous materials can form a uniform thin layer on the wall, improving the efficiency of heat transfer.
It should be noted that the specific selection also needs to consider various factors such as the nature, source, composition and process requirements of the material. When selecting the falling film evaporator, reasonable decisions should be made according to the characteristics of different materials in order to achieve the most optimal production effect.