Enhanced thermodynamic modeling in the techno-economic assessment for biomass valorization

Abstract

The increasing demand for sustainable alternatives to fossil-derived chemicals has encouraged the development of biorefinery processes capable of converting biomass into high-value products. However, the reliability of techno-economic assessments (TEA) in these processes depends strongly on the accuracy of the thermodynamic models used to describe phase equilibria. This dissertation presents an integrated framework combining thermodynamic modeling, process simulation, and economic evaluation to study the production of guaiacol from pyrolysis bio-oil. In the first case study, two process configurations were simulated in Aspen Plus: (i) guaiacol production and (ii) guaiacol and levoglucosan co-production. Economic indicators, obtained using Aspen Process Economic Analyzer, showed that in guaiacol-only scenario, the Minimum selling Price (MSP) reduces from 3,100 to 2,200 USD/t as capacity scales from 15 to 150 kty, the addition of a second compound in the portfolio reduced guaiacol MSP by 15%–20%, which is lower than the current negotiation price (5000 USD/t). The second case study focused on experimental and computational evaluation of thermodynamic models. Liquid–liquid equilibrium data for the water–guaiacol–acetic-acid system were obtained and used to regress binary parameters for the NRTL and NRTL-HOC models, which were then compared with UNI-FAC predictions. The regressed models reproduced the experimental data with greater accuracy, improving phase-equilibrium representation and process performance. The developed approach highlights the role of thermodynamic modeling as a critical element for reliable process design and techno-economic analysis. Guaiacol production varied from 10.9 to 15.4 kton/y, while the minimum selling price ranged from 3,868 to 4,600 USD/t.