A numerical model based on finite element method for predicting the corrosion of carbon steel under supercritical CO2 conditions

In this work, a numerical model, which involves mass transfer process, electrochemical corrosion at the steel/solution interface, homogeneous chemical reactions, evolution of FeCO3 film on the steel surface, was developed to predict the corrosion evolution of N80 carbon steel in the supercritical CO2 containing oilfield produced water. Meanwhile, the evolution of the physical parameters of the FeCO3 film, such as the film thickness and porosity, and their influences on the corrosion process of steel are incorporated into the model. Different from the existed CO2 corrosion models, this model could not only predict the time-dependent corrosion rate, but also track the transient movement of corroding surface and depositing interface via the arbitrary Lagrangian-Eulerian technology. Through finite element calculation, the numerical results, especially the corrosion rate and FeCO3 film thickness, show a good agreement with the experimental data. This model aims to provide a deep insight into the complicated interaction between the corrosion of steel and the evolution of protective FeCO3 film under supercritical CO2 conditions.