Thermodynamic data of CO2-rich multi-component systems: opalescence measurements versus ASPEN PLUS™ computer simulation

The phase behaviour of reaction and product mixtures of the partial oxidation of propane in dense carbon dioxide was studied. Critical data of pseudo-ternary reaction mixtures (CO2–propane–air, containing fixed amounts of ca. 5 and 23 mol% of air, respectively) as well as those of multi-component product systems (additionally containing ca. 0.1 mol% of acetic acid/methanol and acetic acid/acrylic acid) were experimentally determined by opalescence measurements and compared to ASPEN PLUS™ computer simulations. The influence of the different components on the mixture behaviour was studied and the accuracy of various equations of state (EOS) was discussed. A good agreement between measured and calculated results was obtained up to air concentration of ca. 5 mol% in the reaction mixture with the Peng–Robinson EOS. Increased air proportions (up to 23 mol%) led to larger deviations. The small proportions of oxygenates appearing in the product mixtures of the reaction studied did not significantly influence critical data.