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 degrees C. The electrochemical results showed lower corrosion rates at 20 degrees 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.

Automated summary

This study investigated the corrosion inhibition of L80-1Cr steel by alkanolamine molecules in a CO2-saturated NaCl solution. The results showed that at 20 degrees C, the corrosion rate was more influenced by alkanolamine injection. Experimental and molecular modelling calculations demonstrated that alkanolamine adsorption/desorption played a crucial role in the kinetics and characteristics of FeCO3 formation. Additionally, the efficiency of the inhibitors depended on their chemical structures and adsorption energy on Fe(110), FeCO3(104), and Fe3C(001), with ethanolamine providing the highest efficiency.