1. By evaporation Method:
Natural evaporation: The solution at below the boiling point temperature evaporation, such as seawater drying, in this case, because solvents only on the surface of the solution vaporization, solvent vaporization rate is low.
Boiling evaporation: Heat the solution to a boiling point so that it evaporates under boiling conditions. The industrial evaporation operation is basically this kind.
2. By heating method:
Direct heat source heating it is a mixture of fuel and air, so that its combustion-generated high temperature flame and flue gas through the nozzle directly into the evaporated solution to heat the solution, the evaporation process of solvent vaporization.
The indirect heat source heats the wall of the vessel to the evaporated solution. That is, the heat transfer process in the inter-wall heat exchanger.
3. According to operating pressure:
Can be divided into atmospheric pressure, pressure and decompression (vacuum) evaporation operation. Obviously, for thermosensitive materials, such as antibiotic solution, juice, etc. should be under decompression. and high viscosity materials should be used to heat source heating (such as heat conduction oil, molten salt, etc.) to evaporate
4. By number of effects:
Can be divided into single effect and multiple-effect evaporation. If evaporation produces two steam direct condensation no longer used, called single effect evaporation. If two steam is used as the next effect heating steam, and multiple evaporators in series, this evaporation process is multiple effect evaporation.