1. According to the evaporation mode:

Natural evaporation: that is, the solution evaporates at a temperature below the boiling point, such as seawater salt. In this case, the solvent vaporizes only on the surface of the solution, and the solvent vaporizes at a low rate.

Boiling evaporation: Heat a solution to boiling point and cause it to evaporate at boiling state. Industrial evaporation is basically the same.

2. According to heating mode:

Direct heat source heating it is the mixture of fuel and air, so that the combustion of high temperature flame and flue gas through the nozzle directly sprayed into the evaporated solution to heat the solution, so that the solvent vaporized evaporation process.

An indirect heat source heats the walls between the containers and passes the solution to be evaporated. That is, the heat transfer process in the interwall heat exchanger.

3. According to the operating pressure:

It can be divided into atmospheric pressure, pressure and pressure (vacuum) evaporation operations. Obviously, for heat-sensitive materials, such as antibiotic solutions, juice, etc., should be carried out under reduced pressure. High viscosity materials should be heated by pressurized high temperature heat source (such as heat conduction oil, molten salt, etc.) for evaporation

4. In terms of effectiveness:

It can be divided into single effect and multiple effect evaporation. If the secondary steam produced by evaporation is directly condensed and no longer used, it is called single effect evaporation. If the secondary steam is used as the next heating steam, and multiple evaporators are connected in series, the evaporation process is multi-effect evaporation.