An efficient and reliable model based on network method to simulate CO2 corrosion with protective iron carbonate films

A mathematical model simulating CO2 corrosion is presented in the form of a set of non-linear, coupled differential equations. For different values of the parameters (pH, pCO2 and flow velocity) that influence the solution, the problem is numerically solved by the network method, which provides all the concentrations of the species from the steel surface to the bulk. Although the model is strongly sensitive to the above parameters, no assumptions are considered as regards the linearization of species fluxes, chemical reaction rates and current densities of the electrochemical reactions. The design of the model is explained in detail and it is run on standard electrical circuit simulation software. As expected, the corrosion rate, an important parameter to know in chemical utilities, increases for lower values of pH and higher values of flow velocity, while changes in pCO2 hardly influence this quantity. The results are very close to the experimental data.

► We model CO2 corrosion. ► We examine changes of corrosion rate for different pH, pCO2 and flow velocity. ► We find out the relation between corrosion rate and the main parameter of the process.