Calculation of vapor—liquid equilibria at elevated pressures by means of an equation of state incorporating association

Abstract

A previously proposed simple equation of state incorporating association is applied to calculate vapor—liqud equilibria (VLE) at elevated pressures for systems formed by polar compounds and hydrocarbons. The pure-component parameters are calculated from experimental saturated vapor pressure and liquid density data. Such parameters are sufficient for the prediction of VLE with reasonable accuracy in binary systems formed by hydrogen sulfide, ammonia, carbon dioxide, carbon monoxide or sulfur dioxide with aliphatic hydrocarbons. All 26 systems formed by various hydrocarbons with the polar compounds analyzed in this paper can be represented within experimental accuracy when only one adjustable binary parameter is introduced. The binary parameter is generalized in terms of the critical temperature, pressure and acentric factor of the nonpolar (aliphatic or aromatic hydrocarbon) component. The equation also predicts saturated liquid and vapor densities with good accuracy.