Corrosion

Issues - Corrosion
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Desalination plants are at a high risk of corrosion due to both their locations and the saline water and chemicals they handle and process under severe operating conditions. Saline water causes localise corrosion: pitting, crevice, galvanic, and stress corrosion. It is also linked to biological fouling and mineral scaling . In order to deal with these demanding operating conditions, conventional metallic material selection was often stainless steel. However, there are many events where stainless steel in desalination units suffered a corrosion failure. This is often attributed to un-adapted stainless steel grade selection and/or to aggressive conditions in “warm” regions where many recent desalination plants are built (high ambient temperature, severe biofouling, etc.)

Corrosion risk is dependent upon: material composition, metallurgy (cast or wrought), service conditions, and on the geometric configuration of units in contact with the saline water. Considering these parameters, a well thought out material selection should reduce the corrosion risk. Existing corrosion may be controlled using cathodic protection. However, cathodic protection for materials used in desalination and at specific operating conditions is not well documented .