Vapor‐liquid phase behavior of the helium‐methane system

Abstract

This report presents more extensive experimental vapor‐liquid equilibria data for the helium methane system than are found in the literature. A static sampling technique was used to obtain vapor and liquid compositions for six temperatures between −180° and −85°C. and pressures up to 2,000 lb./sq.in.abs. Data at 2,000 lb./sq.in.abs. were extended to the critical temperature of the mixture. Average scatter of the data from the smoothed lines is approximately 1% of the helium concentration or 0.03 mole % helium, whichever is larger. Vapor compositions at −140°, −160°, and −180°C. were analyzed by a different technique and scattered on the average from the smoothed curve less than 4% of the methane concentration. Comparisons are drawn between the data of this study and the previously published work of Kharakhorin. The solubility of helium in liquid methane was found to be considerably less than the values indicated by Kharakhorin. Experimental data are presented in tabular form and in various phase composition diagrams. The behavior of the helium‐methane system is seen to be very similar to that of the helium‐nitrogen system, with helium being much less soluble in methane than in nitrogen. The data were satisfactorily represented by means of the Krichevsky‐Kazarnovsky equation. Extrapolations to higher pressures should be feasible.

Effective Critical Constants for Helium for Use in Equations of State for Natural Gas Mixtures

“…An example for isothermal data near 124 K is shown in Figure 2. It can be seen that the data sets of Heck and Hiza, 31 DeVaney et al, 32 and Rhodes et al 33 are mostly consistent, but the data of Sinor et al 30 are systematically too high and the data from Fontaine 34 exhibit large internal scatter. As cubic equations of state are known to behave poorly near mixture critical points, 11 the pTxy data for (methane + helium) above 190 K were also eliminated from consideration.…”

“…The enhancement factor equals the quotient of the (experimental) partial pressure of methane and the saturation vapor pressure of pure methane at the same temperature, that is, f = y CH 4 P/P CH 4 sat . 30 For isothermal data, the enhancement factor approaches unity in the limit of zero pressure. An example for isothermal data near 124 K is shown in Figure 2.…”

“…One of the methods by which the pTxy data for (methane + helium) were assessed for consistency was by analyzing the vapor enhancement factors of methane. The enhancement factor equals the quotient of the (experimental) partial pressure of methane and the saturation vapor pressure of pure methane at the same temperature, that is, f = y CH 4 P / P CH 4 sat . For isothermal data, the enhancement factor approaches unity in the limit of zero pressure.…”

Solubility of Helium in Liquid Argon, Oxygen, and Carbon Monoxide.

“…The experimental apparatus and operating procedures have been described in detail (13,14). A static sampling cell of approximately 100-cc.…”

“…A number of investigators (3-7, 9, 12) have directed their attention to the solubility of helium in liquid nitrogen. Several studies of the solubility of helium in liquid methane also have been made (8,10,14,15) and data have recently been reported for the helium-argon system (11) and the helium-oxygen system (1,2). The object of this investigation was to determine the solubility of helium in the liquefied gases argon, oxygen, and carbon monoxide.…”