Validation of a new apparatus using the dynamic method for determining the critical properties of binary mixtures containing CO2 and a n-alkane

In this paper the experimental setup of a new apparatus able to provide the critical properties of binary mixtures with known overall composition using a dynamic method is described. Critical temperatures (Tc) and critical pressures (Pc) of binary mixtures composed of carbon dioxide and n-alkanes (CO2 + n-pentane, CO2 + n-heptane and CO2 + n-decane) are measured. The critical points are visually determined by observing the critical opalescence and the simultaneous disappearance and reappearance of the meniscus in the middle of the view cell which withstands operations up to 673 K and 20 MPa. The experimental critical data are compared with success to literature database and with their prediction from the PPR78 thermodynamic model.

► A new apparatus to measure critical points was built.
► Critical points were measured using a dynamic method.
► Critical loci of CO2 + alkane binary systems are measured.