Mesures et modélisation des propriétés thermodynamiques du CO2 + difluorométhane (R32): masse volumique, capacité calorifique et équilibre vapeur-liquide

Accurate thermodynamic property data and models are demanded to reduce the design margins of industrial processes based on these fluids. In this work, measurements of density (ρ), heat capacity (c_p), and vapour-liquid equilibrium (VLE) for CO₂ + difluoromethane (R32) have been performed by the vibrating tube densimeter and the magnetic suspension balance densimeter, the visual cell and gas chromatograph, and the differential scanning calorimeter, respectively. Experiments were conducted over the temperatures ranging from (208.3 to 334.3) K and pressures reaching 10.04 MPa at CO₂ concentrations of 0.7, 0.8 and 0.9. The measured data, together with the results reported in literature where applicable, were subsequently applied to regress the binary interaction parameters utilised in the mixture functions of Helmholtz energy model from REFPROP 10 software package. Noticeable improvements have been achieved for the model's ability to represent thermodynamic property data. The most significant achievement exists in density description: compared with the default parameters, the root-mean-square (RMS) deviation has been decreased by half.