Validation of a model of gas and dense phase CO2 jet releases for carbon capture and storage application

• We present the validation of a novel model for near-field sonic CO2 dispersion.
• We validate against experimental data from dense and gas phase releases.
• Accurate predictions are obtained in the near and far-field.
• This work is applicable to high pressure pipelines in CCS scenarios.
• Robust far-field source models can be developed from this work.

Carbon capture and storage (CCS) presents a short-term option for significantly reducing the amount of carbon dioxide (CO2) released into the atmosphere and mitigating the effects of climate change. To this end, National Grid initiated a programme of research known as the COOLTRANS research programme. Part of this work involves the development of a mathematical model for predicting the near-field dispersion of CO2 following the puncture or rupture of a high pressure dense phase pipeline typical of those planned for transport usage in CCS. This article describes the validation of such a model against experimental data on dense phase and gas phase releases from high pressure pipes above ground. The two-component CO2 and air model has proved capable of accurately predicting the near-field dispersing structure of such releases, including the core and radial temperatures within the sonic jets formed. This has required a three-phase accurate equation of state for pure CO2, that also accounts for the latent heat of fusion, as well as a homogeneous relaxation model to allow the modelling of non-equilibrium conditions. The work described demonstrates the capability of the model to provide accurate predictions in the shock-containing near-field region. It provides the basis for developing robust pseudo source conditions for use in CFD studies of far-field dispersion and for use with the pragmatic models used in quantified risk analysis.