Views:1 Author:Site Editor Publish Time: 2021-02-19 Origin:Site
The plate heat exchanger is the most important heat transfer link of the plate exchange system, and its quality directly affects the service life of the equipment. In a plate heat exchanger, since different media involved in heat exchange will be corrosive to the corresponding material plates, in order to avoid leakage, it is very important to select suitable material plates according to different heat exchange media.
1. Type 304 stainless steel
The cheapest and most widely used austenitic stainless steel (such as food, chemical, atomic energy and other industrial equipment). Suitable for general organic and inorganic media. For example, nitric acid with concentration <30%, temperature ≤100℃ or concentration ≥30%, temperature <50℃; carbonic acid, ammonia and alcohols with various concentrations of temperature ≤100℃.
2.304L stainless steel
The carbon content is lower (≤0.03%), so the corrosion resistance (especially resistance to intergranular corrosion, including the weld zone) and weldability are better, and it can be used for semi-welded or fully-welded PHE.
3. 254 SMO high-grade stainless steel
It has excellent resistance to chloride pitting and crevice corrosion, and is suitable for media containing salt water, inorganic acid, etc. that cannot be used with type 316.
It can be used in seawater below 135°C and various concentrations of salt water (NaCl) below 165°C. Titanium has good corrosion resistance in organic acids below the boiling point (such as concentrated nitric acid, concentrated carbonic acid, etc.) and dilute lye.
5. Titanium-palladium alloy
This is unalloyed titanium added with palladium (0.12%~0.25%), thus significantly improving the corrosion resistance of titanium in acid media (especially in less severe conditions). It can be used for dilute sulfuric acid with concentration ≤10% and temperature ≤70℃.
6. Nickel 200
This is a pure nickel plate containing more than 99% nickel. Mainly used for high concentration (50%~70%), high temperature (up to the boiling point) caustic solution (NaOH, KOH, etc.). However, it is very sensitive to crevice corrosion caused by chlorides such as brackish water.
7. Hastelloy C-276
It has excellent corrosion resistance to various concentrations of sulfuric acid and is one of the few materials that can be used for hot concentrated sulfuric acid; widely used in organic acids (such as formic acid, acetic acid), high-temperature HF acid and a certain concentration of hydrochloric acid (<40% ), phosphoric acid (≤50%); chloride, fluoride and organic solvents (such as methanol, ethanol).