Prediction of solid solute solubility in supercritical CO2 with cosolvents using the CPA EoS

Abstract

Supercritical carbon dioxide (scCO2) is widely used in separation processes applied to the food, chemistry, pharmaceutical and material industries. The knowledge of the solubility of solid solutes in scCO2, with or without cosolvents, is essential for the design and optimization of extraction, fractionation and purification processes. This work evaluates the accuracy of Cubic Plus Association equation of state (CPA-EoS) to predict the solubility of solutes in ternary and/or quaternary systems from the binary interaction parameters. The solubility of 12 solid solutes in scCO2 in presence of different organic cosolvents was investigated, totalizing 19 systems at pressures between 8 and 40 MPa, temperatures ranging from 308 K to 353 K and concentrations of cosolvent varying from 0.73 to 10 mol%. The overall average logarithmic deviation (ALD) between experimental and calculated data with CPA-EoS was 0.47, which is better than that obtained with PR + COSMOSAC previously reported in the literature. Furthermore, the effects of temperature, pressure and of cosolvent type and concentration on the solubility were well estimated with the CPA-EoS.