An experimental setup for investigating the blowdown of liquid CO2 down to -50°C

•The JIP CARDICE project and its objectives are described briefly.•The hardware needed to perform CO2 blowdown in realistic conditions and the metrological layout are detailed.•The proposed solution, a fully instrumented 2m3 vessel, is described, capabilities and limitations are disclosed.•Pressure, temperature (in the fluid and in the shell of the vessel), heat flux through the shell, and mass flowrate are measured as a function of time during blowdown of CO2.•The detection and quantification of solid CO2 inside the different compartments of the setup is facilitated with optic ports specifically designed and used to observe phase transitions and monitor liquid level.•A typical blowdown case is presented.•The experimental uncertainties are discussed, and the methods used to derive indirect parameters like the vapour volumetric fractions are described. In many Carbon Capture and Storage (CCS) technologies, CO2 is transported in a dense phase between 1 and 10 MPa, depending on the temperature. Previous investigations demonstrated that major accidents may occur during transportation or transfer operations in case of vessel or pipe depressurization to the atmosphere. Amongst the scenarios potentially leading to this, tank blowdown is a major concern due to two factors: the risk of brittle rupturing caused by low temperatures and the possibility of dry ice formation in the piping. Current flow models cannot properly model this, and further experimental evidence and detailed data are required. To provide the required information, a specific experimental setup was developed and tested. The tank is a 2 m3 sphere, carefully insulated and connected to a 40 mm diameter, 3 m long release pipe terminated by a discharge orifice to control the depressurization rate. The pipe can be connected either on the side of the vessel to release the gaseous phase or at the bottom to release the liquid phase. Optic ports are provided on the vessel and on the pipe to observe phase transition and monitor the liquid level. The instrumentation is a set of pressure transducers and arrays of thermocouples inside the CO2 and in the shell of the vessel. The tank is continuously weighed during the blowdown and the data are treated so that the mass flowrate can be obtained. The performance of the system is discussed based on a gaseous phase blowdown starting from a half-filled vessel with liquid CO2 at -38 °C and 1 MPa. Detailed data are presented and discussed. All phases - liquid, gas, and