Volumetric properties of high temperature, high pressure supercritical fluids from improved van der Waals equation of state

In the present work, a modified equation of state has been presented for the calculation of volumetric properties of supercritical fluids. The equation of state is van der Waals basis with temperature and density-dependent parameters. This equation of state has been applied for predicting the volumetric properties of fluids. The densities of fluids were calculated from the new equation of state at different temperatures and pressures in the supercritical region. The predicted densities have been compared with those obtained from the experiment, over a broad range of pressure. It is found that the new equation of state yields excellent results in comparison with 1894 experimental data points with overall average absolute deviation percent (AAD %) of 0.98% in density for the pure studied compound. The studied fluids are: CH4, C2H6, C3H8, C4H10, C5H12, C6H14, C7H16, C8H18, C10H22, C12H26, C2H4, C6H6, C6H12, C7H8, O2, N2 and CO2.