Prediction of uapor-liquid equilibrium of natural gas using a molecular thermodynamic approach

Abstract

The Leiva equation of state has been selected for modelling Vapor-Liquid Equilibrium of natural gas at high pressure. The binary Interaction parameter, Kᵢj was evaluated from binary experimental data. Initially the Leiva equation was tested on binary systems, and then applied to a number of natural gas mixtures in the range 310-366 K, 17-206 atm. Comparing to the Soave(SRK) equation on binary and ternary systems, the Leiva equation offers some improvement in accuracy over the Soave equation in bubble point pressure calculatons at high temperatures. Its representation of vapor molar volume is similar to that of the Soave but gives better results for liquid molar volume predictions.