Abstract

International audience; The work presented in this paper forms part of the EC FP7 CO2PipeHaz project which aims to address the fundamentally important and urgent issue regarding the accurate prediction of fluid phase, discharge rate, emergency isolation and subsequent atmospheric dispersion during accidental releases from pressurised CO2 pipelines. Such pipelines are considered to be the most likely method for the transportation of captured CO2 from power plants and other industries to subsequent sequestration sites, and their safe operation is of paramount importance as their inventory is likely to be large. The developments presented describe a state-of-the-art, multi-phase heterogeneous discharge and dispersion model capable of predicting the near-field fluid dynamic and phase behaviour in such CO2 releases. Predicting the correct fluid phase during the discharge process in the near-field is of particular importance given the very different hazard profiles of CO2 in the gas and solid states. Validation of the model is undertaken using recently obtained experimental data from discharge tests. Model predictions are found to describe the experimental observations very well, with a high level of agreement between the two. The study clearly demonstrates that models addressing accidental releases of CO2 must include shock-capturing methods and complete three-phase formulations for prediction of the physical and thermodynamic properties of CO2 in order to accurately predict the discharge and dispersion phenomena of interest in risk assessments.

Abstract

International audience; The deployment of a complete carbon capture and storage chain requires a focus upon the hazards posed by the operation of CO2 pipelines and intermediate storage vessels, and the consequences of accidental release. The aim of this work is the construction of a computational fluid dynamic model capable of accurately representing the complex physics observed in such a release, essential if dispersion phenomena are to be accurately predicted. The interacting thermo-physical processes observed include those associated with the rapid expansion of a highly under-expanded jet, leading to an associated sonic flow structure. In such a release, it is also possible for three phases to be present due to the expansion and subsequent Joule-Thomson cooling, and a suitable equation of state is required to elucidate a system's composition. The primary objective of this work is the consideration of these physical processes, and their integration into a suitable numerical framework which can be used as a tool for quantifying associated hazards. This also incorporates the validation of such a model using data available in the literature and also using that recently obtained, and presented here for the first time. Overall, the model has provided an excellent level of agreement with experimental data in terms of fluid and sonic structure and temperature measurements, and good agreement with respect to composition data.

Abstract

International audience; Without a clear understanding of the hazards associated with the failure of CO2 pipelines, carbon capture and storage (CCS) cannot be considered as a viable proposition for tackling the effects of global warming. Given that CO2 is an asphyxiant at high concentrations, the development of reliable validated pipeline outflow and dispersion models are central to addressing this challenge. This information is pivotal to quantifying all the hazard consequences associated with the failure of CO2 transportation pipelines, which forms the basis for emergency response planning and determining minimum safe distances to populated areas. This paper presents an overview of the main findings of the recently completed CO(2)PipeHaz project [1] which focussed on the hazard assessment of CO2 pipelines to be employed as an integral part of CCS. Funded by the European Commission FP7 Energy programme, the project's main objective was to address this fundamentally important issue. Document type: Conference object