In industrial production, it is often necessary to evaporate a large amount of water, consume a large amount of energy, heat the water to produce steam, and then condense the steam to achieve the purpose of evaporating water. These vapors contain a lot of latent heat, so they should be recycled. If the secondary steam is introduced into the heating chamber of another evaporator, as long as the operating pressure and solution boiling point of the latter are lower than the pressure and boiling point of the secondary steam, the introduced secondary steam can still play a heating role. This operation mode is multi effect evaporation.
Each evaporator in multi effect evaporation is called one effect. The evaporator adding raw steam is called primary effect, and the evaporator using the secondary steam generated by primary effect as heat source is called secondary effect, and so on. Multi effect evaporation is an evaporation system that operates several single effect evaporators in series. For example, the secondary steam of the first effect is used as the heating steam of the second effect evaporator. Similarly, the newly generated secondary steam of the second effect evaporator can be used as the heating steam of the third effect evaporator, and so on. Due to the repeated utilization of heat energy, the consumption of raw steam is significantly reduced, the cost is greatly reduced and the efficiency is increased. Multiple evaporators are connected and operated together to form a multi effect evaporation system.
- Several evaporators are connected for operation. The secondary steam generated during evaporation in the former primary effect evaporator is used as the heating steam of the latter primary effect evaporator;
- The heat energy is reused for many times to significantly reduce the heat energy consumption;
- The main types of evaporators are: single effect evaporator, double effect evaporator, three effect evaporator, four effect evaporator, five effect evaporator, etc. the number of effects depends on the comprehensive consideration of material properties, equipment investment and operation cost;
- According to the characteristics of materials, downstream, countercurrent, advection, cross flow and other processes can be flexibly adopted;