Failure analysis of corroded condensate water pipelines used in natural gas purification systems

The corrosion of carbon steel condensate water pipelines significantly compromises the safety of natural gas production. In this study, a corroded carbon steel pipeline retrieved from an operational facility was thoroughly analyzed to determine the root causes of corrosion. The results present a failure analysis that moves beyond identifying oxygen-induced corrosion as the root cause. Through multi-technique characterization, we establish a direct link between the spatial variation in corrosion severity/product distribution and localized hydrodynamic conditions. A synergistic mechanism is revealed: at the high-turbulence elbow, intense fluid shear strips protective Fe 3 O 4 layers while enhanced oxygen mass transfer promotes non-protective FeOOH/Fe 2 O 3 formation. In contrast, stable Fe 3 O 4 scales form in calmer regions. These findings provide a nuanced mechanistic understanding for designing targeted anti-corrosion strategies in condensate water systems. • Fe₂O₃, Fe₃O₄, and FeOOH are the main corrosion products. • Links spatial corrosion variation to localized flow conditions, not just velocity. • A corresponding formation pathway for these corrosion products is proposed.