Stress corrosion cracking of acidic water tanks in petrochemical acidic water gas treatment units and anti-corrosion methods

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This post was last edited by Wang Wei2 on 2024-11-10 at 09:29. The acidic water tanks in the sour water gas units of petrochemical sulfur plants are subject to strong corrosion when operating at temperatures between 50–80°C, as the raw water contains various substances such as H2S, NH3, CO2, CN−, phenols, and oil. For epoxy coatings and various other anti-corrosion coatings used inside tanks, the damage is severe; problems arise within less than 3 months of use, such as bulging, hardening of the coating, and cracking. There is significant stress corrosion on exposed metal surfaces, causing severe damage to storage tanks; this poses a major challenge within the petrochemical industry. Titanium nanopolymer coating is used as an anti-corrosion coating. Nearly 2 years of use have proven that the anti-corrosion coating performs very well under these conditions. It solves the problem of conventional special anti-corrosion coatings lacking both corrosion resistance and temperature tolerance, filling the gap in domestic applications under such conditions. Problems associated with the use of stainless steel lining: Stainless steel is welded to the tank body, resulting in an interface layer in between. Using stainless steel as a lining in this type of operation presents the following problems: The test results for 1Cr18Ni9Ti in sulfur-containing wastewater (under conditions similar to those in oil refineries), at a temperature of 80°C ± 5°C, with an immersion time of 48 hours and a pH level of 3–4, show a mass change of -0.093% per 2 days, which amounts to -18.2% per year. Without considering stress corrosion cracking and pitting. In chemical industrial wastewater and water supply chemical dosing storage tanks (for aqueous solutions of chemicals; the conditions are less severe than those involving acidic water), stainless steel plates with a thickness of 2 mm became perforated in less than a year, rendering them unusable.