High-pressure phase equilibria have been calculated for systems of C54 triglyceride (rapeseed oil) + propane + carbon dioxide and C54 triglyceride (rapeseed oil) + ethanol + carbon dioxide, in the temperature range of 313-353 K and at pressures of 60-120 bar. The Peng-Robinson equation of state with a conventional mixing rule involving two parameters (2PCMR) was used, The critical parameters of triglycerides have been estimated by predictive and extrapolative methods using very limited pure-component data, The available experimental phase-equilibrium data for the binary systems were well correlated with the 2PCMR model, At pressures lower than 80 bar, the predicted ternary phase equilibria are in good agreement with measurements. At higher pressures, a simultaneous correlation of binary and ternary phase-equilibrium data was necessary to improve the calculated ternary phase diagrams.