Corrosion Behavior and Corrosion Prediction Model of L360 Steel in H₂S/CO₂ Coexistence System

Using H₂S partial pressure, CO₂ partial pressure, temperature and flow rate as variables, a high temperature and high pressure reactor was used to simulate the corrosion process of L360 natural gas pipeline. Nine orthogonal experiments were performed, and corrosion products were characterized by SEM, EDS, and XRD. The results show that when CO₂/H₂S partial pressure ratio was 33~300, the main corrosion products were FeS, the reactions were dominated by H₂S and most of them were uniform corrosion. The order of the influencing factors was as follows:H₂S partial pressure > temperature > flow rate > CO₂ partial pressure. A corrosion prediction model with a H₂S/CO₂ partial pressure ratio of 33~300 was established. Considering the effects of the above four factors, MATLAB multivariate linear regression was used to obtain the values of various parameters. It was verified that the accuracy of the corrosion prediction model was good.