A new high pressure phase equilibrium cell featuring the static-combined method: Equipment commissioning and data measurement

Abstract

A new equilibrium cell featuring a floating piston with an internal variable volume and phase sampling mechanism was designed and commissioned for the measurement of phase equilibrium data. The experimental technique can be extended to the static-combined method. The apparatus was tested by measuring vapor-liquid equilibrium data for the binary system of carbon dioxide + n-hexane at 313.15 K. New experimental vapor-liquid equilibrium data were also measured for the binary systems of carbon dioxide + 1,1,2,2 tetrafluoroethyl 2,2,3,3 tetrafluoropropyl ether at four temperatures, viz. (303.15, 313.15, 323.15 and 333.15) K and modeled using the Peng-Robinson Equation of State. Data close to the mixture critical points were modeled using a scaling law. The average expanded uncertainty for T, P, x1 and y1 for all systems in this work were 0.08 K, 0.002 MPa, 0.004 and 0.0007, respectively.