Modelling of accidental release process from small rupture of pressure CO2 vessel

Leakage of carbon dioxide (CO2) vessel can significantly affect the safety in the field of carbon capture and storage technology (CCS). Studies of small rupture leakage in the early accidental release stage are required. In this study, to investigate the release from small rupture under different working conditions, an experimental CO2 blowdown device was presented, transient pressure and mass flow rate were respectively measured and calculated, and also a pressure vessel release model was built. Besides, homogeneous model and phase separation model were employed to analyze the phase distribution in the vessel. According to the experiment results, the phase separation model shows a better applicability in small scale rupture leakage. The effect of initial pressure on pressure release is not obvious, while the effect of the initial temperature and nozzle location on pressure release is significant. When nozzle is located in the bottom of the vessel, pressure release becomes faster and more dangerous.