LAUSR

Abstract A volumetric equation of state (PVT behavior of a fluid) is often based on a critical isotherm. Soave-Redlich-Kwong and Peng-Robinson are by far the most popular cubic equations of state. These equations use the first and second differential conditions at the critical point to obtain the parameters but fail to reproduce the P-V-T behavior near the critical point. A new simple equation is proposed for the critical isotherm which matches experimental data for a variety of molecules in the entire range from critical point to ideal gas condition as well as the liquid region. The new proposed critical isotherm equation matches experimental data of a wide variety of compounds much better than these cubic equations of state employed commonly.