Liquid‐liquid‐vapor equilibrium compositions were measured for the nitrogen‐ethane binary and the nitrogen‐methane‐ethane ternary systems from –255° to –219.8°F and at pressures up to 591 psia. A forced‐recirculation apparatus was employed for the determinations. Experimental results were interpreted and correlated. Optimum operating temperature for nitrogen separation has been suggested.

Isothermal P‐x data for the binary system ethylene‐propane were measured at four temperatures by means of a total pressure apparatus. Equilibrium vapor compositions were calculated with the supporting properties obtained from the Clausius Equation of state. In the calculation, the parameters of the Clausius Equation were considered to be temperature‐dependent. The validity of the apparatus and the proposed method of calculation was established by comparing satisfactorily phase equilibrium values obtained in this study with those reported in the literature for the binary systems argon‐nitrogen and argon‐methane. In addition, several vapor compositions were also determined experimentally for the binary system ethylene‐propane to confirm the accuracy of the calculated results.

The temperature-dependent parameters Qa and 6 of the Redlich-Kwong equation of state evaluated from vapor pressures and saturated liquid volumes for 13 pure components were correlated in terms of 7r. The coefficients of these correlations were further generalized in terms of . The generalized correlations have been successfully used to compute the 3 and Qb values for seven arbitrarily selected components other than those included in the generalization. The applicability of the values computed from the generalized equations was further demonstrated by evaluation of pure-component properties and by the calculation and prediction of vapor-liquid equilibria data for eight binary systems at 32 isothermal conditions.

The Clausius equation was modified for the calculation of vapor-liquid quilibria in binary and multicomponent systems. In the modification, the three parameters of the equation were considered temperature dependent. Molal volumes of saturated liquid and vapor together with the condition that the fugacities of the vapor and the liquid phase are equal a t the condition of equilibrium were used for evaluating the parameters of pure components. Applications were made successfully to systems nitrogenmethane, nitrogen-orygen, argon-orygen, nitrogen-argon, argonmethane, carbon dioxide-hydrogen sulfide, carbondioxide-propane, hydrogen sulfide-n-butane and nitrogen-argonoxygen. On a modifii I'huation de Clausius pour calculer les h u ilibres entre vapeur et liquide dam des systhes binaires et I cornposants multipIes. Dam la modification en question, on a considCrC Ies trois paramhtres de I'Bquation coinnie dkpendants de la temperature. Pour Cvaluer les paramhres de composants purs, on a utilisk les volumes molaires du liquide et de la vapeur s t u r h , avec la condition que 1es fugacitk des phases dc la vapeur et du liquide soient &gales A l'btat d'kquilibre. 0 1 1 a appliqut avec succb t'kquation modifike aux syst&mes azotembthane, anhydride carbonique -hydrogPne sulfurk, anhydride carboniquepropane, hydroghe sulfur&, butane normal et azoteargonoxyghe.he purpose of this investigation is to continue our effort in seeking a suitable equation of state for calculating phase equilibrium in binaries and multicomponent systems. For the purpose of calculating vapor-liquid equilibria for pure components, an adequate equation of state must satisfy the following three requirements at saturation conditions"' : V, is less than unity, have a tendency to reach a peak and then fall sharply without ever rising againfd'.The Clausius equation is given by:

Vapour–liquid equilibrium data were determined at three isothermal conditions for the binary system benzene–n‐octane using a modified Gillespie still. Non‐ideality of the vapour phase was evaluated and log γ values were correlated.