Refining CO2 infiltration models for pipeline release scenarios

Accurate modelling of carbon dioxide (CO2) dispersion and infiltration into buildings is essential for assessing the risks associated with accidental releases from carbon capture, utilisation, and storage (CCUS) infrastructure. This study presents an integrated analytical and computational framework for evaluating CO2 infiltration, incorporating a modified equation of state (EOS) to account for non-ideal gas behaviour. The original infiltration model, based on wind- and buoyancy-driven ventilation, is extended using a virial EOS. Key performance metrics are used to validate the model against experimental data and computational fluid dynamics (CFD) simulations. A comprehensive set of 30 case studies is used to assess model performance across a range of building geometries and environmental conditions. Results show that the modified EOS has minimal impact on far-field predictions, confirming the robustness of the ideal gas assumption under ambient conditions. Importantly, the study finds that CO2 impurities do not significantly affect far-field dispersion once ambient pressure is reached, though they may influence near-field behaviour at the release point.