Vapor-liquid equilibrium for the system hydrogen—benzene—cyclohexane— n -hexane

Abstract

This paper presents vapor-liquid equilibrium data for the system hydrogen—benzene—cyclohexane— n -hexane over the pressure range of 500 to 2,000 lb./sq.in.abs. and the temperature range of 200° to 300°F. Experimental equipment was constructed that was capable of operating at pressures of 3,000 lb./sq.in.abs. and at temperatures of 400°F. A static equilibrium cell, which had a sample port for both the liquid and vapor phases, was employed. Separation of the hydrogen from the hydrocarbons by means of a liquid nitrogen cold trap was utilized before performing the hydrocarbon analyses on a mass spectrometer. Three hydrocarbon mixtures were charged to the equilibrium cell, and for each charge, isotherms of 200°, 250°, and 300°F. were run for equilibrium pressures of 500, 1,000, 1,500 and 2,000 lb./sq.in.abs. These thirty-six quaternary equilibrium runs resulted in a total of one hundred and forty-four equilibrium data points. In addition, four binary equilibrium runs were determined both for the hydrogen-benzene and hydrogen-cyclohexane systems. A modified version of the Chao-Seader correlation was used to predict the data. This correlation was able to predict all the quaternary equilibrium ratios with an average deviation of 4.86%.