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-HBO 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. (c) 2007 Elsevier B.V. All rights reserved.