Abstract
Modeling pressurized releases in QRA procedures is a key step in obtaining a reliable description and prediction of hazards. The application of these procedures to hazards related to CCS and EOR infrastructures poses many problems strictly related to the peculiar thermodynamic behaviour of the CO2 (Koorneef et al, 2009). Difficulties in the prediction of the discharge behaviour of the CO2 during rapid depressurizations can influence calculations concerning the atmospheric dispersion and the eventuality of a dry ice bank formation (Mocellin et al., 2015).
In order to fill some gaps concerning especially compressible CO2 discharges, starting from self – collected laboratory scale experimental data, a semi – predictive model is proposed with the aim of describing a sudden release from a pressurized vessel.
The model is based both on conservation equations as well as suitable correlations to give a description of heat – transfer mechanisms. In addition, the Peng – Robinson equation of state is employed in order to predict the CO2 thermodynamic behaviour and to correctly manage both the gaseous and the dense phase if necessary.
The application of the model shows good agreement with the experimental data series, especially in terms of pressure profiles and discharge time. In addition, the vessel thermal dynamics is adequately predicted both for the releases at higher pressure investigated especially when related to an internal surface temperature experimentally derived.
