Materials for Next Generation CO2 Transport Systems (MATTRAN)

The large-scale implementation of Carbon Capture and Storage (CCS) cannot be realised without a pipeline network that is economic, safe and efficient. In the UK, this means designing and constructing a 'next generation' transport system for the collection of CO2 from disparate anthropogenic sources, predominantly power plant, and transporting it under supercritical conditions through more densely populated areas for offshore storage. This has not been attempted anywhere in the world and presents key challenges which the UK can take the lead in solving. Transport is an integral and critical link in the chain between capture and storage and failure to address the issues associated with transportation immediately could significantly delay the execution of CCS in the UK. This project, Materials for Next Generation CO2 Pipeline Transport Systems (MATTRAN) will take that lead and provide the tools and information necessary for pipeline engineers to select appropriate materials and operating conditions to control corrosion, stress corrosion cracking and fracture propagation in pipelines and associated equipment carrying supercritical CO2 from the capture processes likely to be realised in the near and long term future. However, in order to be able to achieve this overall aim, fundamental scientific research is required to provide the data and predictive models necessary to produce accurate and validated predictions. It is recognised that there is currently no standard definition for the composition of the CO2 stream expected from the different capture processes. Small levels of constituents can play a large role in the phase behaviour, thermodynamic properties and solubility of water in the supercritical CO2 stream. The first tasks in the project are therefore to determine the expected ranges of compositional variation and conduct the necessary phase experiments in the supercritical range to characterise the behaviour of a selected subset of the CO2 streams judged to have the biggest impact. This experimental data will be used to address another gap in the existing knowledge on supercritical CO2 process streams, the prediction of the phase behaviour and thermodynamic properties using existing equations of state. Currently there is no consensus in the literature regarding which equation of state provides the most accurate predictions in the supercritical range. This presents a problem for pipeline engineers in modelling the hydraulic behaviour of the CO2, both in the pipeline and in the event of an accidental or controlled release. In this project, the experimental data will be compared with existing equations of states and new models developed and provided to the hydraulic and fracture propagation models that will be used in the interconnected Work Packages. The remaining Work Packages involve the specification of the pipeline and associated equipment materials to determine the conditions under which corrosion, stress corrosion cracking and fracture propagation will occur. Once the constituents in the CO2 stream have been selected, experiments investigating corrosion, stress cracking and fracture propagation will be conducted. This database of experimental data does not currently exist and without this data, the operating conditions of the pipeline and the property requirements of the materials cannot be safely defined. The MATTRAN project brings together a consortium of scientists, mathematicians and engineers working from the molecular scale of the CO2 in the pipeline to the macro-scale of fracture propagation and pipeline failure to produce the data required in a systematic and co-ordinated manner that will ensure that the required results are generated efficiently and quickly disseminated to the industry. In addition, the MATTRAN consortium involves academics and researchers from five institutions and introduces new researchers to the field of CCS research from four of those institutions.