Quantifying Local Corrosion Rate in Atmospheric Storage Tanks Utilizing Advanced Numerical Simulations

The familiarity we possess with traditional fuels stems from extensive research, rigorous testing, and decades of manufacturing and operational expertise. Presently, a wave of novel and alternative fuels, utilizing new feedstocks and manufacturing methodologies, is emerging in the market. However, owing to their recent introduction and the challenges in scaling up to mass production, certain alternative fuels may exhibit variability and pose concerns related to corrosion. Atmospheric storage tanks play a critical role in the safe and reliable handling of hazardous substances in major accident hazard establishments. To prevent potential leaks, it is essential to regularly monitor the thickness of their bottom sections. This typically involves comprehensive inspections that are conducted every 10 years or more. Despite the regular thickness assessments, discrete measurements cannot fully capture the most severe corrosion damage, particularly in localized forms like pitting. The primary objective of this investigation is to meticulously trace, analyse the intricate evolution of the metal/electrolyte interface and model the underlying mechanisms governing the initiation and propagation of single as well as multiple interacting corrosion pits. In pursuit of this objective, the research employs the computational framework of COMSOL Multiphysics for conducting numerical simulations executed on a model that intricately amalgamates the complex dynamics of the electrolyte and the electrochemical characteristics at the interface, thereby formulating a phase-field dependent representation of the Nernst-Planck equations. The conducted analyses afford the opportunity to discern and articulate the intricate functional interdependencies governing the corrosion rate concerning pivotal parameters. These parameters encompass not only the electrochemical potential but also encompass variables including the spatial distribution, the number, mutual distance among pits, alongside the influential role played by the electrolyte's chemical composition.