Vapor‐liquid equilibrium behavior of the ethane—n‐butane—n‐hexane system

Abstract A high pressure visual cell was designed and constructed for the study of vapor‐liquid equilibria of rnulticomponmt systems at elevated temperatures and pressures. One of the unique features of this vapor‐liquid equilibrium cell facility resides in the ability to measule pressures using a transducer connectcd directly to the equilibrium chamber of this cell. In addition, the design of this cell, incorporated the capability to permit the withdrawal of vapor and liquid microsamples from the respective phases in equilibrium. The composition of these microsamples was established with a gas chromatographic facility provided with a thermal conductivity detector. The overall performance of this vapor‐liquid equilibriiini facility was tested on the system ethane‐n‐butane for which reliable vapor‐liquid equilibrium data are already available in the literature. Five different charges of the ethane‐n‐butane‐n‐hexane system were investigated with this facility for temperatures ranging from 48.3 up to 143.5°C and pressures up to 7619 kPa (75.19 atm). For these conditions, K‐values were established from the experimental measurements on this ternary system. K‐values calculated using the BWR‐method for conditions corresponding to the experimental measurements produced K‐constants that were in good agreement with the measured values. For these calculations, the original BWR‐equation, constants and mixing rules were employed.