Enhanced corrosion resistance of metal surfaces by film forming amines: A comparative study between cyclohexanamine and 2-(diethylamino)ethanolbased formulations

The use of recycled process water in steam crackers leads to the accumulation of corrosive impurities, hence the need for adequate treatment. Two corrosion inhibitor formulations containing N-[(9Z)−9-octadecen-1-yl]−1,3-propanediamine (N-oleyl-1,3-propanediamine) with either cyclohexanamine (CHA) or 2-(diethylamino)ethanol (DEAE) were compared for their performance. Electrochemical impedance spectroscopy and visual observations showed that the two formulations offered comparable protection against corrosion. Bengal Rose testing and experiments conducted using a quartz-crystal microbalance with dissipation monitoring (QCM-D) indicated that the two formulations yielded similar coverage of the metal surfaces, and that the kinetics of mass adsorption were also similar. QCM-D data further suggested that the films formed with the two formulations had similar rigidity, and contact angle measurements indicated that they formed films with comparable hydrophobicity, which were equally effective in isolating the metal surfaces from water. Keywords: Steam system, Corrosion, Inhibitor, Amine, Films, Closed loop