Capillary Constant and Surface Tension of the Propane–Nitrogen Solutions

Abstract This paper presents experimental data on the capillary constant and the surface tension of a propane–nitrogen binary solution in the temperature range from 308.15 to 360.15 K at pressures from the saturation pressure of pure propane up to 4 MPa. The concentration of nitrogen in the solution, as well as the orthobaric densities of the liquid and gas phases, was determined from the equation of state of the solution. A new correlation for the surface tension of pure propane has been obtained. The temperature and concentration dependences of the capillary constant and the surface tension of the solution were approximated by empirical functions, whose coefficients were determined by regression analysis. The maximum deviations of the proposed equations from the experimental data do not exceed 0.04 mm2 (for the capillary constant) and 0.08 mN·m–1 (for the surface tension). It is shown that the surface tension of the propane–nitrogen solution decreases with an increase in temperature and nitrogen concentration. The surface tension of the solution was calculated by the Parachor method. The results are applicable to the optimization of processes involving liquefied hydrocarbon gases and engineering calculations in the gas sector.