Service Life Prediction of Anti-Corrosion Coatings on Crude Oil Storage Tank Exterior Walls in High Salt Spray Environments

Service life prediction of anti-corrosion coatings on crude oil storage tank exterior walls in high salt spray environments requires comprehensive consideration of environmental corrosion mechanisms and coating performance. Chloride ion penetration (diameter 0.36nm) in salt spray can penetrate coating micropores and initiate electrochemical corrosion. Epoxy resin water absorption swelling rates exceeding 5% will lead to a 40% reduction in adhesion, and the synergistic effect of ultraviolet radiation accelerates molecular chain scission. It is recommended to use glass flake coatings (60% improvement in impermeability) or fluorocarbon topcoats (weather resistance up to 15 years), and verify through the ISO 12944-9 standard 2000-hour salt spray test.

Service life prediction requires the establishment of a multi-parameter evaluation system: 1) Electrochemical impedance spectroscopy monitors a 50% decrease in impedance value as a warning threshold; 2) In accelerated aging tests, a coating blistering area ≤5% is a qualified standard; 3) Actual cases show that water-based epoxy coatings can maintain 10 years of protection in coastal environments, while epoxy coal tar only lasts 5-8 years. A 100,000 m³ storage tank using an "epoxy zinc-rich primer + polyurethane topcoat" combination, after EIS testing, still maintained 65% of its initial impedance value in the 7th year.

Optimization schemes should include: 1) Controlling surface roughness to 40-70 μm and total dry film thickness ≥400 μm during construction; 2) Visually inspecting weld areas every 6 months and rinsing salt deposits with fresh water; 3) Using a digital twin model to predict service life.