Cellular Automata simulation of corrosion and scaling processes taking place in CO2 saturated solutions

CO2 is a reactant for internal corrosion of oilfield o r carbon capture transport pipelines. Understanding and modelling this corrosion process can contribute to reduce the cost of over-dimensioned design of riser pipes. Modelling these processes presents cha llenges especially when several complex processes, which operate at different length scales, are takin g place. The aim of the present study is to use Cellular Automata (CA) to model CO 2 corrosion processes. CA models are discrete comput ational systems in which the evolution of the state of each cell in the modelling space is determined by the current state of the cell and that of its neighbour h od cells. Corrosion processes and scale precipitation in the form of a protective scale on the metal substrate a re taken into account during the CA simulation. The al gorithm for the CA model is written with MATLAB® programming software. A two dimensional lat tice is considered with two different spaces, the upper half of the lattice represents th e aqueous solution and the lower half, the metal. T he state of each solution cell considers all the conce ntrations of species involved in the corrosion proc ess. In order to establish the evolution rules, a Moore’ s neighbourhood is used. The model information is validated against experimental data obtained from t he immersion of carbon steel coupons in CO 2 saturated solutions at 80 C for 7 days. The corrosion rate is monitored using Electrochemical Impedance Spectroscopy (EIS). The results of this w ork will increase the understanding of the CO 2 corrosion processes providing a base model to predi ct the evolution of the corrosion rate with time under different environmental conditions.