PHASE EQUILIBRIA IN THE H2/CH4SYSTEM AT TEMPERATURES FROM 92.3 TO 180.0 K AND PRESSURES TO 140 MPa*

Abstract

Experimental measurements of liquid-vapor phase equilibria in the system H₂/CH₄ are reported for ten temperatures in the range 92.3 to 180 K, and pressures to 140 MPa. The mixture critical line and the pressure-temperature trace of the three-phase region solid-liquid-vapor have been located. The three-phase region and the critical line intersect at T = 91.5 K and P = 147 MPa to form an upper critical end point. Experimental results have been compared with predictions of three equations of state, Peng-Robinson, Reclich-Kwong and Deiters, and with calculations based on statistical mechanical perturbation theory.