Experimental Solubility Data for Binary Mixtures of Ethane and 2,2,4-Trimethylpentane at Pressures up to 6 MPa Using a New Variable-Volume Sapphire Cell

Abstract

A variable volume apparatus of low cell volume (approximately 10 cm3) was designed and commissioned for measuring phase equilibrium and thermodynamic property data. The experimental procedure and equipment capability for phase equilibrium measurements were validated by measuring isothermal phase equilibrium (T–P–x) data for binary mixtures involving carbon dioxide + n-hexane and ethane + n-octane. There is good agreement between data measurement using the new equilibrium cell and previous measurements reported in the literature. New T–P–x data were also measured for the binary mixture of ethane + 2,2,4-trimethylpentane. The data were correlated using the Peng–Robinson equation of state and the van der Waals mixing rule. The expanded uncertainties in the measurements were evaluated as 0.07 K, 0.02 MPa, and 0.008 for the temperature, pressure, and liquid mole fraction, respectively.