The evaporation process differs from other chemical unit operations, as it involves both heat exchange and separation during operation. Therefore, when selecting the material for evaporators, it is not only necessary to consider the material's corrosion resistance but also its ability to withstand high-temperature corrosion. Additionally, the thermal conductivity of the material should also be taken into account in the heat exchange section.

Common materials used in evaporators include carbon steel, 304 stainless steel, 316L stainless steel, duplex steel, and titanium.

For non-corrosive materials, carbon steel is the initial choice.

For materials that require cleanliness and are non-corrosive, or have minor corrosion, 304 stainless steel is a suitable choice.

For operations under severe corrosive conditions with no chloride ions present or low chloride ion content, 316L stainless steel can be selected.

4. For materials containing chloride ions, especially under acidic operating conditions, duplex steel or titanium is generally chosen. However, duplex steel or titanium are not suitable for all operating conditions. For environments with stronger acidic chloride ions, better materials need to be selected.