Strategies for maximizing the bio-oil valorization by catalytic transformation

• A continuous thermal treatment of bio-oil in phase gas retains the pyrolytic lignin.
• The thermal treatment of bio-oil enhances its subsequent catalytic up-grading.
• 400–500 °C is optimum temperature for the thermal treatment.
• The treatment of raw bio-oil is preferable to the treatment of its aqueous fraction.
• At 500 °C, 77 wt% oxygenates of raw bio-oil are liable to catalytic valorization.

A study was carried out on the continuous thermal treatment of raw bio-oil and of its aqueous fraction (obtained by adding water) based on the interest of this strategy for separating the pyrolytic lignin, which enhances the valorization of the treated bio-oil in a subsequent in-line catalytic step. It was determined that after the direct thermal treatment of raw bio-oil, 77 wt% oxygenates originally contained in the bio-oil are capable of catalytic valorization, whereas after the treatment of the bio-oil aqueous fraction, 64 wt% of bio-oil oxygenates are amenable to further valorization.