Phase equilibria of simple fluids at cryogenic temperatures.

Abstract

Isothermal vapour-liquid equilibrium measurements have been measured by a forced-recirculation type of apparatus; the temperature range investigated being 115-137°K for the binary system argon-methane and at 123.44°K for the ternary system argon-nitrogen-methane. Results were presented in the form of activity coefficients gamma as a function of compositions; high pressure and low, pressure equations being used in their determinations. Binary and ternary constants for the one-suffix Redlich-Kister equation have been found to represent both the binary and ternary data adequately. Experimental data were examined for consistency by noting the trend of the terminal values of the activity coefficients at the investigated temperatures. Owing to scarce literature data pertaining to the ternary effect, a qualitative treatment has been made.