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Corrosion of acidic water tanks in refining units is a common risk issue in the petrochemical industry. Its causes are complex, and it can lead to safety accidents. The following are the key points: 1. Main types of corrosion and their causes – Wet hydrogen sulfide corrosion: The large amount of H₂S dissolved in acidic water reacts with the carbon steel comprising the tank walls, leading to hydrogen blistering, peeling, and even partial detachment of the inner surface; this is the most common form of corrosion. Stress corrosion cracking: Under the combined effect of media such as H₂S, NH₃, and CN⁻ along with the residual welding stresses in the tank, brittle cracks tend to form in the weld area and its surrounding regions; 70% of corrosion perforations occur in these areas. Other forms of assistive corrosion include electrochemical hydrogen evolution corrosion, pitting caused by Cl⁻ ions, and fatigue erosion resulting from alternating acid and alkali conditions, all of which further accelerate the failure of the tank. II. Mainstream anti-corrosion protection solutions: Combined anti-corrosion approach – this involves using anti-corrosion coatings in combination with sacrificial anodes. Compared to traditional epoxy fiberglass materials, this solution has proven to be free from issues such as delamination or degreasing damage after 6 years of actual use, offering more stable protection. Selection of special anti-corrosion coatings: Prioritize coatings resistant to acids and alkalis, capable of withstanding alternating acid and alkali environments at pH 0-14, and effective in preventing the penetration of H₂S and NH₃ ； In coastal areas with high salt fog, measures can be taken to enhance resistance to chloride corrosion. Operational control measures: Conduct routine inspections of the equipment every 2 hours, carry out thickness measurements of tanks and pipelines twice a year, regularly check the nitrogen sealing and water sealing systems, and promptly identify any potential corrosion issues.