Modelling of Carbon Dioxide Venting in Carbon Capture and Storage Studies: Design and Safety Implications

Abstract

The reduction of the impact of carbon dioxide on the environment is a key driver of the energy transition, which will progressively reduce the use of fossil fuels and will promote the development of viable technologies. This process will be based on renewable energy sources to reduce, to any possible extent, the production and the release of carbon dioxide into the atmosphere. CCS (Carbon Capture and Storage) projects are more and more an ineludible stage of this process. In the last decade, a significant segment of chemical engineering research has been devoted to the management of carbon dioxide release scenarios, which can result both from an accidental loss of containment or from an emergency venting of carbon dioxide streams. This gas is asphyxiating and toxic, depending on concentration levels. Consequently, acquiring familiarity with its dispersion modelling is a key task for process and process safety engineers. On the other hand, carbon dioxide presents a very peculiar behaviour, as it is a dense gas and, below the triple point, its release can produce solid formation. The article presents a relatively simple multi-stage validated model, covering the release scenario from the source, as a heavy gas, up to the neutral Gaussian dispersion, considering also the very low temperatures possibly resulting from the JT (Joule Thomson) effect. Two case studies, carried out through the Megaris Platform, illustrate the application of the methodology. It can be useful in the design phase and in the QRA studies, to properly size and locate the venting stack and to minimize any health upsets for the operators