In the acid water stripping units used in the petrochemical industry, the acid water tanks are prone to stress corrosion cracking
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The figure below shows the commonly used 5,000-cubic-meter acidic water tank in petrochemical industries. The feed water contains H2S, as well as various other substances such as CO2, CN‑, phenols, and oils; its pH level is 10±0.5, and the temperature of the feed water ranges from 65 to 70°C. Under such operating conditions, the surface corrosion of carbon steel tanks is relatively severe. Stress corrosion cracking occurs at welds and at the bends in the base metal (such as at the areas where the steel plates near the bottom of vertical columns in tanks are compressed and deformed).
In this case, it is recommended to upgrade the material of the acidic water tank, as well as to conduct regular inspections and maintenance of the tank. Consider using corrosion-resistant alloy materials or lining the tank with an anti-corrosion coating, while ensuring that the welding processes meet the required standards, in order to reduce the risk of stress concentration and corrosion. .