Electrochemical and molecular modelling studies of CO2 corrosion inhibition characteristics of alkanolamine molecules for the protection of 1Cr steel

Effects of alkanolamine molecules on the corrosion inhibition of L80–1Cr steel were studied in a CO2-saturated 1 wt% NaCl solution at well downhole temperatures of 20 and 80 °C. The electrochemical results showed lower corrosion rates at 20 °C, for which corrosion rates were more influenced by the alkanolamine injection. The experimental results and molecular modelling calculations using DFT revealed that alkanolamine adsorption/desorption played a determining role in the kinetics and characteristics of FeCO3 formation. Additionally, the dependency of inhibitor efficiency on both chemical structures and adsorption energy on Fe(110), FeCO3(104) and Fe3C(001) was demonstrated, resulting in the highest efficiency provided by ethanolamine.