Electrochemical Corrosion Simulation of Elbow for CO₂ Transportation Based on Experiment

Electrochemical tests were carried out on X70, X80 and X90 pipeline steels in CO₂ saturated solution. A simplified model of three-electrode system was established using COMSOL Multiphysics software, and the applicability of the simulation method was verified based on experimental data. Finally, the geometric model of X80 pipeline steel elbow was established to simulate its electrochemical corrosion process, and the distributions of potential and corrosion current density on elbow surface were analyzed, as well as the current density on different parts of the elbow. The results show that there was a slight difference in the potential distribution on elbow surface. The inner side of the elbow had more negative potential and greater current density than the outer side of the elbow, and was more likely to be damaged by corrosion. Along the direction of fluid flow, the corrosion rate of the elbow increased first and then decreased, and the corrosion rate of the middle and later sections of the elbow was the largest.