Boiling liquid expanding vapour explosion in CO₂ small scale experiments

Carbon capture and storage systems require handling large volumes of high pressure CO₂. Having thorough knowledge of the related hazards is essential, as is knowing how to prevent, detect, control and mitigate accidents. This paper gives a short description of CO₂ Boiling Liquid Expanding Vapour Explosions (BLEVEs) and presents results from preliminary, small scale experiments with CO₂ BLEVEs. The mechanism of superheated liquid CO₂ boiling is not fully understood. Analogies can be made between gas explosions and rapid phase transitions occurring in BLEVEs. The experiments indicate that violent boiling may occur before the spinodal point is reached. Shock waves in the experiments were generated by the decompression of the vapour in the vessel before rupture. However, our recent theoretical models show that boiling also will contribute to shock strength. We observed fragment velocities up to approximately 100 m/s. Such fragments are a serious hazard. Large scale tests and laboratory tests are needed for validation of equation of state models and for the development of computational fluid dynamic codes for use in risk analysis.