How to Protect Plate Heat Exchanger from Corrosion

How to Protect Plate Heat Exchanger from Corrosion

1, Reduce the aggressiveness of the medium.

Marine heat exchanger manufacturers can control stress corrosion by removing dissolved oxygen and oxidants in the medium, reducing the mass concentration of Cl- in the medium, and strictly controlling the mass concentration of sulfur in the medium is also an effective measure to control stress corrosion. Grasp the plate heat exchanger medium on the plate heat exchanger corrosion, can extend the service life of the plate heat exchanger.

2, Improve the plate heat exchanger structure construction.

In order to avoid residual liquid and sediment retention, welding try to use double-sided butt welding and continuous welding, avoid lap welding and spot welding. In the welding process should fill the wire to ensure that the weld is well formed.

3, Reduce the residual stress.

According to practical experience, caused by plate heat exchanger stress corrosion rupture stress is mainly residual stress, and residual stress is mainly caused by cold working and welding of internal stress. Heat treatment of cold work and welded parts helps to eliminate residual stress, which also helps to prevent the generation of stress corrosion. Often use stress annealing heat treatment to eliminate residual stress or other methods to eliminate residual stress, such as hydraulic testing, vibration aging and hammering.

4, Electrochemical protection method.

Stress corrosion fracture is an anodic dissolution process under stress. Therefore, it can be controlled by electrochemical protection method. Electrochemical protection method can not only prevent the plate heat exchanger stress corrosion fracture, but also in the protection of the parameters selected under the conditions of the appropriate cracks can still make it stop expanding. Sacrificial anode protection or surface spraying of corrosion-resistant metal can be used.

5, Add corrosion inhibitors.

Corrosion inhibitor to prevent corrosion of stainless steel stress corrosion rupture occurs in the activation potential area, must use adsorption-type corrosion inhibitor to cover it. The formation of dense adsorption film on the metal surface, inhibiting the metal corrosion process. So that the surface of the plate heat exchanger is protected from corrosion.