Methodology for Corrosion Inhibitor Persistency Studies in Batch Inhibition

A novel methodology and experimental apparatus were developed to address the limitations of previous studies and investigate corrosion inhibitor persistency under batch treatment conditions. This approach effectively removed all residues after inhibitor application and prevented O₂ ingress during film formation and subsequent steps. A model compound corrosion inhibitor (CI) was utilized to validate the methodology and investigate the effects of solvent on CI persistency. In all experiments, CI was applied in situ on the prepared API 5L X65 steel rotating cylinder electrode (RCE) inside the empty deoxygenated glass cell using a holder and vial. The setup used a reservoir of CO₂-sparged uninhibited brine to continuously dilute the test electrolyte at a constant flow rate. Electrochemical measurements were performed at 20-minute intervals to characterize the inhibition behavior over time.