Importance of Corrosion Modeling in CO2 Transportation Pipelines

Carbon Capture, Utilization, and Storage (CCUS) is needed to avoid the release of CO2 into the atmosphere. CCUS includes capturing CO2 from industrial sources, utilizing it in various processes, or securely storing it in geological formations. An important aspect of CCUS is the transportation of CO2, often via high-pressure pipelines. While CO2 pipeline transport has been established, particularly in the United States for enhanced oil recovery (EOR), existing corrosion models require refinement to account for evolving operating conditions and various impurities present in the CO2 stream.<br/>Corrosion in CO2 transportation pipelines is a major issue, primarily due to the presence of water and other impurities such as hydrogen sulfide (H2S), sulfur dioxide (SO2), and nitrogen oxides (NOx), which can lead to the formation of carbonic acid and other corrosive species. The impact of these impurities on corrosion rates, phase behavior, and materials integrity makes it necessary to have careful modeling. Our goal is to improve corrosion models to enhance the safety and reliability of CO2 transport infrastructure.<br/><br/>In the CarbonAdapt project, one of the main motivations is to better predict corrosion in CO2 transportation pipelines. As part of this project, mechanistic and semi-mechanistic models are developed and tested to predict the corrosion rates induced by CO2, H2S, organic acids, specifically targeting the internal corrosion of mild steel pipelines. Existing literature data as well as experimental data has been used to populate the model, encompassing underlying theories. By narrowing down the spread of data through considering the effects of pipeline material, impurity types (e.g., H2O, H2S, NOx) and concentrations, flow-regime, water solubility, among others, it is possible to have models that to an acceptable level can follow the experimental patterns. The strengths and weaknesses of our developed models will be discussed in the context of CCUS.