Three-Dimensional Scheme of Supercritical Carbon Dioxide Extraction of Heavy Hydrocarbon Mixture in (Pressure; Temperature; Recovery) Coordinates

A heavy hydrocarbon mixture represented by C 17 –C 31 carbon groups was investigated to determine extraction recoveries by supercritical carbon dioxide in the ranges of 12–65 MPa for pressure and 50–90 °C for temperature. The purpose of the study was to obtain a three-dimensional scheme of the SC–CO 2 /heavy hydrocarbon mixture system in pressure–temperature–recovery coordinates, which allows the prediction and numerical modeling of phase behavior. At lower temperatures, high recoveries were attained at lower pressures. The highest recovery of 93% was obtained at 70 °C and 56 MPa. The recoveries greater than 65% were determined at the breakover points where the pressure increased by 7 MPa with a temperature increase of 10 °C. The phase envelope, 3D scheme, and the equations describing the boundaries of the system are presented.