Abstract
An experimental apparatus was set up to measure the CO solubility in ternary mixtures of water-CO.glucose, water-CO -malic acid and in a quaternary mixture of water-CO -malic acid-glucose at different concentrations of malic acid (0.01 and 2.68 g in 100 g of water) and of glucose (4 and 12 g in 100 g of water). The range of pressure tested was between 7.5 and 15.0 MPa at 40 and 50°C. The experimental results were compared with the equilibrium conditions evaluated by applying different thermodynamic models by means of the process simulation software Aspen Plus®. The Peng - Robinson - Wong - Sandler (PRWS), the electrolytic non-random two liquids (ELECNRTL) and the completely predictive Soave-Redlich-Kwong (PSRK) thermodynamic models were applied to solve the equilibrium. The experimental results show that the CO solubility strongly depends on glucose concentration, decreasing when it increases in the system. On the contrary it is only slightly affected by the malic acid concentration. The solubilities predicted by the PRWS model exhibit a good agreement with the experimental data in the pressure and temperature range tested, once main coefficients of binary interaction are derived from ternary systems at one reference condition.