Corrosion Mitigation Using Biobased Polyols in a Crude Oil Simulant Environment

This research endeavors to protect structural steel from corrosion by employing varying concentrations (0%, 1%, 2%, and 3% by wt.) of five biobased polyols (xylitol, erythritol, maltitol, mannitol, and sorbitol) in a crude oil simulant (COS) environment. Steel specimens are corroded in an accelerated manner by exposing them to a dripping flow of COS, containing 1%, 2%, and 3% by wt., of these biobased polyols for a duration of 48 h. Potentiodynamic polarization tests are conducted to quantify the corrosion damage incurred to these specimens. Tafel extrapolation was performed on the polarization curves to determine the corrosion current densities, corrosion rates, and other electrochemical parameters. Visual analysis revealed that all five polyols effectively reduced corrosion damage to steel in the COS environment. The presence of polyols in the COS reduced the corrosion rate by up to 84% and improved the corrosion inhibition efficiency by up to 87%. The adsorption of polyols in the COS environment followed Langmuir adsorption isotherm. The standard free energy of adsorption ranges from −15.71 kJ/mol to −18.50 kJ/mol, suggesting that polyols physisorbed onto the steel surface, reducing both the anodic and cathodic reactions, thereby reducing corrosion damage.