Experimental study of the influence of burst parameters on the initiation of CO2 BLEVE

•Vent size of 8 mm and 15 mm were two critical parameters under different burst pressures.•Supercritical state CO2 was unstable and its phase transition was more complex compared to the liquid state CO2.•Initial burst pressure of 8 MPa was an ideal condition when the burst vent size was 8 mm.•At the pressure of 10 MPa, gaseous CO2 liquefied gradually, making the gas-liquid interface disappear. A small-scale experimental system was constructed to simulate the initiation of CO2 BLEVE process in different phase state. Dynamic pressure parameters after disc burst were analysed to supplement the influence rules of vent size and burst pressure to the intensity of CO2 BLEVE. Comparisons between the supercritical phase state CO2 and liquid CO2 on the pressure parameters were made to reveal the phase state influence to the initiation of CO2 BLEVE. The vent size of 8 mm and 15 mm were two critical parameters under different burst pressures. The changing of pressure became irregular when the vent size surpassed 8 mm, and the pressure rise value will never surpassed the pressure drop value when the vent size reached or surpassed 15 mm. The supercritical state CO2 was unstable compared to the liquid state CO2. A more complex phase transition in the discharge process caused the pressure parameters changing became irregular; especially when the inner pressure reached 10 MPa and CO2 became a supercritical state fluid. After burst, the fluid releasing form the vessel instantly and limited space was reserved for the fluid to swell in the vessel, causing the inner pressure can’t rebound in time, which eventually led the overpressure disappear.