1. According to the evaporation method: natural evaporation: that is, the solution temperature is lower than the boiling point of the steam, such as seawater salt, in this case, since the solvent evaporates only on the surface of the solution, the solvent evaporation rate is low. Boiling evaporation: The solution is heated to the boiling point to evaporate it. Industrial evaporation operations are basically of this type.
2. According to the heating method: direct heat source heating is to mix fuel and air, so that the high-temperature flame and smoke generated by combustion are directly injected into the evaporation solution through the nozzle to heat the solution, so that the solvent is evaporated and evaporated. An indirect heat source heats the vessel walls until the solution evaporates. That is, the heat transfer process in the interlayer heat exchanger.
3. According to the operating pressure: it can be divided into atmospheric pressure, atmospheric pressure and vacuum (vacuum) evaporation operation. Obviously, for heat-sensitive materials, such as antibiotic solutions, fruit juices, etc., it should be carried out under reduced pressure. High-viscosity materials should be heated and evaporated under pressure with a high-temperature heat source (such as heat transfer oil, molten salt, etc.).
4. According to the number of effects: it can be divided into single-effect evaporation and multi-effect evaporation. If the secondary steam produced by evaporation is no longer used for direct condensation, it is called single-effect evaporation. If secondary steam is used as low-efficiency heating steam, and multiple evaporators are connected in series, the evaporation process is multi-effect evaporation.
5. According to the situation that the solution stays in the evaporator, the commonly used partition heat transfer falling film evaporators can be roughly divided into two categories: circulating type and one-way type. Where is the refrigerator evaporator?
Circulating evaporator In this type of evaporator, the solution is circulated through the evaporator. Due to different reasons for circulation, it can be divided into natural circulation and forced circulation.