Phase equilibria of CO2 with components in the light naphtha cut of tyre derived oil

- Binary phase equilibria of CO2 + TDO close-boiling points components were measured.
- Phase transition pressures increase with temperatures for constant composition.
- Supercritical CO2 can isolate 1,2,3-trimethylbenzene at T ≥ 343 K from TDO.
- Experimental phase equilibrium data are satisfactory correlated with RKS EoS.

Phase equilibria of CO2 + limonene, CO2 + 1,2,3-trimethylbenzene, CO2 + p-cymene and CO2 + m-cymene systems were measured to investigate the possibility of extraction of these components from tyre derived oil using supercritical CO2. Measurements were conducted using variable-volume view cells at four temperatures between 313 and 358 K, with solute mass fractions ranging from 0.0159 to 0.635. The maximum total solubility pressure measured was 16.5 MPa. The phase behaviour of the systems indicated that an increase in system temperature leads to an increase in phase transition pressure at constant composition. The solubility differences between the components increase slightly with the temperature, however a sufficient pressure difference exists for 1,2,3-trimethylbenzene to be isolated at temperature higher than 343 K. Experimental data of four binary systems were satisfactory correlated by using the Redlich-Kwong-Soave equation of state, along with Mathias-Klotz-Prausnitz mixing rules, which include two temperature independent binary interaction parameters.

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