Thermodynamic and exergetic analysis of high-value compound recovery from pyrolysis bio-oil

The economic viability of pyrolysis-based biorefineries requires the comprehensive valorization of bio-oil beyond the conventional recovery of low-value light fractions. While most studies emphasize acetic acid recovery (~0.60 USD/kg), this work investigates the recovery of high-value compounds, specifically guaiacol (~5 USD/kg) and levoglucosan (30–77 USD/kg). Rigorous thermodynamic modeling was conducted in Aspen Plus using the NRTL-HOC framework to represent strong liquid-phase non-idealities and vapor-phase molecular association effects, particularly acetic acid dimerization. The UNIFAC-DMD method was employed for property estimation where experimental parameters were unavailable. An exergetic analysis was performed to identify major sources of exergy destruction within the separation sequence. Simulation results demonstrate technically feasible separation routes enabling the selective concentration of target compounds. The results further indicate that adopting flexible purity specifications can significantly reduce thermodynamic inefficiencies. Overall, the integration of high-value compound recovery with rigorous thermodynamic and exergetic assessment provides a consistent pathway for improving both the economic and thermodynamic performance of pyrolysis-based biorefineries.