Study of dry ice formation during blowdown of CO₂-CH₄ from cryogenic distillation column

Experimental study of accidental leakage behaviour of liquid CO2 under shipping conditions

“…As it can be observed in Table 2, the discharge process resulted in a variable amount of inventory solidification inside the vessel in the performed tests, ranging from 19% at high pressure to 39% at low pressure conditions. Despite also considering smaller orifice sizes (1 mm) than those indicated by Shafique et al to avoid solid formation inside the system [25], this work demonstrated that solidification of inventory still occurred in the vessel. Moreover, varying the orifice size did not show any significant difference in rate of inventory solidification at the end of the leakage process.…”

“…Shafiq et al [25] derived a correlation to determine the ideal blowdown orifice size to adopt in case of sudden emergency to mitigate the risk of inventory solidification during the unplanned release of CO2-CH4 with a ranging CO2 concentration of 20 -80 mol% (Equation 8).…”

“…Shafiq et al [24] performed a simulation work of CO2 depressurisation from a high-pressure vessel (4 MPa and 233 K) in relation to orifice sizes of 4.325 mm, 6.325 mm and 8.325 mm and found that risk of solidification and blockages during the blowdown process can be drastically reduced by selecting the smallest orifice diameter. In a following work, the authors [25] performed a modelling campaign and relative experimental validation to scrutinise dry ice formation during blowdown of CO2-CH4 mixture from a cryogenic distillation column at initial temperature of 243 K and pressure of 4 MPa.…”