Supervisor:
Simon Pedersen

Co-Supervisor:
Dennis Severin Hansen

Assessment Committee:
Thomas Helmer Pedersen (Chair)
Professor, Massimiliano Errico, SDU, Denamark
Pricipal Scientist, Gaute Svenningsen, Institute for Energy Technology (IFE), Norway

Moderator:
Thomas Helmer Pedersen

Abstract:

Carbon Capture, Utilization, and Storage (CCUS) is increasingly recognized as a crucial component in global strategies to mitigate greenhouse gas emissions and achieve climate goals. As capture technologies evolve, the ability to transport CO2 from emission sources to storage sites or utilization pathways becomes essential for large-scale implementation. Yet, the transportation of CO2 remains underdeveloped, hindered by both technical limitations and regulatory gaps. Although transport accounts for roughly 25% of total CCUS costs, progress is slowed by the lack of common CO2 quality standards, challenges in selecting suitable materials, and the corrosive influence of impurities under operational conditions. Furthermore, the absence of standardized monitoring practices introduces uncertainty in both system performance and regulatory assessment. Adding to these challenges, CO2 remains a policy-dependent and commercially unestablished commodity, making investment decisions increasingly difficult under evolving regulatory and market conditions. Although initiatives such as ISO standardization and large-scale projects like Porthos and Northern Lights are progressing, a unified framework for reliably monitoring impurities across the CCUS chain has yet to be established. This thesis aims to establish foundational frameworks for CO2 transportation by clarifying specification thresholds, investigating impurity-driven corrosion mechanisms, and evaluating impurity monitoring strategies along with their associated measurement uncertainty. It addresses three interrelated challenges. The first concerns the identification of technical and regulatory barriers to CO2 transport and their influence on infrastructure design. The second involves understanding how impurities contribute to corrosion and material degradation under transport-relevant conditions. The third focuses on evaluating monitoring approaches that can support quality control and regulatory compliance across the CCUS value chain. These contributions provide targeted guidance for infrastructure planning, material qualification, and impurity monitoring, directly supporting the development of standardized frameworks essential for the safe, cost-efficient, and scalable deployment of CO2 transport systems. To achieve this, the thesis integrates policy and infrastructure analysis with process modeling, corrosion experiments under realistic conditions, and critical evaluation of monitoring accuracy and reliability. 31,104 simulations using flue gas from Aalborg Portland were used to assess how operating conditions in MEA-based capture influence the carryover of impurities into the captured CO2 stream, and how this affects the energy demand required to meet purity compliance thresholds. Corrosion experiments conducted under dense-phase CO2 and low temperatures reveal that low amounts of H2O and NO2 can trigger significant material degradation in carbon steels, while 9Cr alloys offer improved but not complete resistance. The need for accurate impurity quantification is further emphasized through a critical assessment of monitoring strategies, where gas chromatography (GC) and Fourier transform infrared spectroscopy (FTIR) emerge as viable options, depending on the context. Inter-operator differences in FTIR calibration demonstrate that impurity quantification is highly dependent on the chosen absorption regions, reinforcing the need for standardized procedures. Together, the findings advance the technical understanding of impurity behavior, material performance, and monitoring uncertainty in CO2 transport.

Future research may focus on standardizing impurity thresholds across the CCUS value chain to support regulatory consistency and technical integration. Cross-chemical interactions between co-existing impurities require closer examination due to their potential impact on materials and downstream processes. Emulating realistic operating conditions, including batch and continuous transportation, can improve the relevance of experimental data. Stakeholder transitions, such as those from capture to transport or storage, remain insufficiently defined and require clear protocols to manage parameters like pressure, temperature, boil-off gas, and phase changes. These factors can alter CO2 composition and introduce risks not addressed by current specifications.