Phase equilibria of near critical CO2+propane mixtures with fixed oils in the LV, LL and LLV region

High Pressure Phase Equilibrium Engineering

“…Mixtures of CO 2 + propane exhibit a Type I phase behavior in the classification of Van Konynenburg and Scott (1980) and a single solvent phase is obtained in a wide range of temperature and pressure. Particularly, the solvent mixture presents always a single phase (liquid or supercritical) at pressures higher than the CO 2 critical pressure (73.8 bar) (Hegel et al 2006).…”

“…The main drawback of propane is its high flammability. However, it could be avoided by the presence of CO 2 in the solvent mixture (Hegel et al 2006). In this case study the phase behavior of binary and ternary systems from CO 2 + propane + jojoba oil are analyzed.…”

“…Therefore, the design of the extractor operating conditions should focus on the lower section of the ternary diagrams previously discussed where low concentrations of oil coexist with the solvent. (b) In order to guarantee a good solvent power and an efficient use of the propane + CO 2 solvent mixtures partial miscibility should be avoided (Hegel et al 2006(Hegel et al , 2007. (c) With regard to the safety of the entire process (high pressure extractor, separators o cyclones, recycling solvent system, pumping, etc.…”

“…), the extractor should be operated with the higher CO 2 concentration for an economic process without loss of extraction efficiency. Hegel et al (2006Hegel et al ( , 2007 studied the operating conditions for the extraction of vegetable oil by percolation of liquid CO 2 + propane mixed-solvent. In this operation, a vapor phase remains in the extractor while the liquid percolates through the bed of grounded seeds.…”

Solvent recovery from soybean oil/n-butane mixtures using a hollow fiber ultrafiltration membrane

“…Many other solvents have been proposed for soybean oil extraction, with many advantages and drawbacks. Supercritical carbon dioxide and compressed gases such as propane and n-butane are interesting solvents, since they do not leave residues in the oil or in the cake (Seth et al, 2007;Hegel et al, 2006;Hegel et al, 2007). Most of these solvents, compared to the traditional method of extracting with hexane, do not exceed the extraction yields obtained with n-hexane (18 -20% oil/kg of soybean) (Hegel et al, 2007), except n-butane (unpublished results).…”