Depressurization of a 50 km Long 24 inches CO2 Pipeline

We describe the results of depressurizing an onshore 50 km long, 24 inches buried pipeline from initially supercritical conditions. The event has been simulated using OLGA, a multi-phase pipeline simulation tool, recently adapted to handle single components like CO2. The simulated results deviate from the measurements during the two-phase release period. The obtained results suggest that small amounts of impurities matter, even at concentration as low as 1 Mole %. In addition, the simulated onset of boiling and the mass transfer rate between the liquid and gaseous phase is not supported by the experiments.