Evaluation of The Corrosion Inhibition by a Coco-Modified Imidazoline in CO_2-H_2S

摘要

A corrosion inhibitor formulation based on coconut oil modified imidazolines has been evaluated as carbon dioxide (CO_2) and hydrogen sulphide (H_2S) corrosion inhibitor for UNS G10180(1) using a sodium chloride (NaCI) 3% solution. Testing techniques included potentiodynamic polarization curves and electrochemical impedance spectroscopy. In absence of the inhibitor, steel was susceptible to uniform corrosion in presence of CO_2, to blistering when H_2S was present, and blistering and pitting corrosion when both CO_2 and H_2S were added to the 3% NaCI solution. The maximum inhibitor efficiency was found for the CO_2-saturated NaCI 3% solution. Corrosion was also mitigated when both CO_2 and H_2S were added to the solution, although some pitting was found in steel. For comparison, the same tests were conducted employing a reference imidazoline; and the corroded surfaces were characterized employing scanning electronic microscopy (SEM).