Liquefaction of oil palm empty fruit bunch using sub- and supercritical tetralin, n-dodecane, and their mixture

- Supercritical tetralin achieved higher conversion than n-dodecane at lower pressure.
- EFB conversion at 400 °C in tetralin reached 97.1% with the addition of Fe3O4 and H2.
- Higher temperature at 400 °C led to increasing gas product yield in both solvents.
- Activated solid residue after liquefaction showed good adsorption capacity for CO2.

The direct thermochemical liquefaction of oil palm empty fruit bunch (EFB) was performed using sub- and supercritical solvents. The total feedstock conversion at 400 °C in tetralin reached 91.8%, and 97.1% with the addition of Fe3O4 and H2. Increasing the reaction temperature to 450 °C with n-dodecane present led to a slight increase in the total feedstock conversion. At 400 and 450 °C in n-dodecane, the liquefaction reaction afforded almost identical feedstock conversions (>77%) and high liquid product yields; however, the reaction pressure exceeded 10 MPa. The variations of the reaction performance in the n-dodecane/tetralin mixture were correlated to the quantity of tetralin. Tetralin was an ideal solvent that promoted an efficient EFB liquefaction process and suppressed char formation. The solid residues collected after the liquefaction reaction were thermally activated, and some of them showed good CO2 adsorption capacity when compared to activated carbons.

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