Apparatus for simultaneous determination of the densities and heat capacities of liquids and of liquids with dissolved gas under an extended range ofpressure (0.1-100 MPa)

This design note describes an experimental device, based on a Setaram C-80 calorimeter and an Anton Paar 512P densimeter, developed in order to measur e densities and heat capacities at constant pressure of liquids and of liqu ids with gas dissolved. Pressure ranges from 0.1 to 70 MPa for the density measurement and from 0.1 to 100 MPa for the heat capacity determination, at temperatures from 303 to 473 K. The specific arrangement incorporated in t he apparatus and the method of transfer of samples into the measurement ves sels required for the study of these mixtures are also detailed. The functi oning of this instrument was tested by measuring the heat capacity of liqui d n-hexane, with calibration performed with water. Comparison with literatu re data obtained by an indirect method indicates that the deviation is less than 0.6%. The results of an investigation of a binary mixture, of n-decan e and carbon dioxide, which has two phases under normal conditions, is also given.