The influence of CO2 mixture composition and equations of state on simulations of transient pipeline decompression

We find that the saturation pressure can change significantly when certain impurities are present, even when in small quantities. A simplifying assumption that CO2 is pure can therefore lead to significant underestimation of the fluid pressure during the decompression, with consequences for the prediction of running ductile fractures. The choice of EOS was found to mainly affect the velocities of the initial decompression wave, with the long-time evolution of the pipeline decompression remaining relatively unchanged. The temperature minimum did neither depend significantly on the choice of EOS nor the presence of impurities.