Using a New Proposed Influence Parameter of Gradient Theory for CH4/n-alkane Binary Systems: What Advances Can Be Achieved?

Abstract

The main aim of this modeling investigation is to improve the performance of the gradient theory for binary systems of methane and n-alkane. To achieve this aim, the gradient theory (GT) is combined with the volume-translated Peng-Robinson equation of state (VTPR EOS) for accurate description of phase equilibrium and surface tensions of methane/hydrocarbon systems. To improve the phase equilibrium calculations, the binary interaction parameters of VTPR EOS for methane/hydrocarbon systems have been determined based on the mole fraction of methane in liquid phase. A new correlation of the influence parameter based on the densities of bulk phases has been suggested. To make the present model predictive, the binary interaction parameters of the mixture influence parameter have been set equal to zero. The results of the model show that the predictions of the present model agree well with experimental surface tensions, especially for very low values of surface tensions (near-critical interfaces).