Corrosion Prediction in Residual CO2 Streams: Shifting the Paradigm

Cost-effective Carbon Capture and Storage (CCS) offers one option for meeting the goals of the Paris Agreement, reached at COP 21 in December 2015. Whilst there have been major efforts to develop technologies for capture and storage, transportation between the two points has received less attention to date. However, there is now an increasing awareness that this is an important focus area. The behaviour of dense phase and supercritical CO2 mixtures containing largeamounts of possible impurities is not well understood. Accurate predictions of the physical properties and corrosion potential of these mixtures will be needed for the cost-effective design and operation of both capture and disposal systems. The overall goal of this project is to improve the predictive tools for both physical properties and corrosion rates and to demonstrate their accuracy against laboratory and field data in order to increase the confidence and gain industry acceptance of the predictions being made. An experimental framework will provide the necessary inputs for the corrosion related aspects of the model, whilst the phase equilibria model will enable exact conditions to be described.

A notable strength of this proposal is that it will bring the resources of a large, internationally renowned corrosion research group to Innovate UK. The project presents a new paradigm in corrosion modelling by linking expertise in Equation of State simulation with experimental studies in an effort to generate reliable corrosion data capable of advancing the understanding of CO2 transport risk and safe operating conditions.
INDUSTRY BENEFICIARIES: The industrial involvement of Woodview and WGK clearly indicates the direct relevance of the work proposed here to industry. The project will develop a fundamental understanding of corrosion in CCS pipelines to a level not achieved elsewhere through the integration of Equation of State modelling and experimental analysis. By demonstrating the feasibility of this study, it is hoped that the initial work will lead to a much larger study which will focus on the development of the first semi-empirical model for impure CO2 transport. The development of such a model will allow pipeline operators, energy companies and oil and gas companies to design, implement and operate safer and more cost efficient pipelines that would otherwise not be possible without a robust prediction model. In turn this will facilitate the UK's ambition to become a global leader in CCS technology, and pipelines in particular, bringing future export potential.
The UK is well placed to become a global leader in developing design and simulation software for CCS systems and this project will contribute to consolidating that position. As set out in the main proposal, poor understanding of pipeline transport corrosion processes is a key uncertainty globally in designing CCS systems. The data produced from this project will significantly enhance the capabilities of CCS simulation software originating from the UK.
POLICY MAKERS & REGULATORS: A better understanding of carbon dioxide pipeline corrosion processes will allow policy makers and regulators to act with greater confidence in terms of (i) ensuring safety, (ii) ensuring risks are managed by defining the safe window (impurity tolerances, pressures and temperatures) for pipeline operation and (iii) understanding the risks associated with upset conditions (i.e. when dehydration systems potentially fail). The former, ensuring safety, is of
course paramount, but without a thorough understanding of the processes involved and an accurate prediction of pipeline longevity, the risk and uncertainty can be increased significantly. As a consequence, this is likely to result in regulations that are over-conservative in most instances, imposing unnecessary costs on CCS systems and thereby hinder deployment, with the risk that the UK could lose its leading position. Leeds University has experience of working with policy
makers and regulators that will assist in communicating the project findings to these stakeholders.
WIDER PUBLIC BENEFITS: There is likely to be concern from the general public about the construction of CCS pipelines, especially in the vicinity of densely populated areas. Being able to demonstrate a thorough understanding of the risk of failure associated with pipeline corrosion would help alleviate such public concerns. More importantly there will be a tangible contribution to public safety from the enhanced understanding of pipeline corrosion mechanisms allowing possible unexpected failures to be avoided.