Measurement and modelling of the ternary phase equilibria for high pressure carbon dioxide–ethanol–water mixtures

A continuous flow apparatus for measuring the phase equilibria of liquids in CO2 is presented. Phase equilibrium measurements have been made on the ternary system CO2–EtOH–H2O at 313 K and pressures of 100–300 bar, and comparisons have been made with literature data where possible. Ethanol partition coefficients, selectivities and loadings for the CO2–EtOH–H2O system at 313 K and pressures of 100–300 bar are reported. Binary data from the literature and ternary CO2–EtOH–H2O equilibrium measurements from this work were compared with results predicted using the Peng–Robinson equation of state with quadratic and Wong–Sandler mixing rules. The phase behaviour of the ternary systems was predicted more accurately with the Wong–Sandler mixing rules than with the quadratic mixing rules.