Coupled hydrodynamic cavitation–hydrothermal separation for biomass valorization: Simulation and experimental validation, and techno-economic assessment

Hydrodynamic cavitation (HC) is an emerging effective pretreatment for biomass, enhancing the bio-product separation. This study simulated and analysed a coupled HC-hydrothermal separation (HTS) process in Aspen Plus and compared its efficiency and economic performance with an HTS-only setup. The HC pretreatment was conducted at 30 °C and 4 bar, and HTS was optimized at 130 °C, 15 bar, 6-min residence time, and a 10 % solid-to-liquid ratio. The integrated HC-HTS approach showed higher energy and exergy efficiencies, with a 38–57 % separation in lignin yield and a 63–88 % improvement in extractive removal over HTS alone. For oak-based sawdust, lignin and extractive removal after HC were estimated using thermogravimetric analysis (TGA), whereas other feedstocks utilised literature data. The techno-economic analysis projected an initial investment of approximately ∼€10 million, with HC-HTS generating positive annual cash flows (€1–€14 million), short payback periods of 0.7–1 year, and positive net present value (NPV) for favorable feedstocks. Sensitivity analysis showed that profitability is primarily influenced by product sales and prices. Overall, the HC-HTS process demonstrated superior technical and economic performance, offering an energy-efficient and economically viable route for biomass volarization through improved recovery and separation of lignocellulosic bioproducts. • A coupled HC-HTS process was simulated and compared with HTS-only simulated process. • Agro-residue (WS, CB, SCB) and hardwood were evaluated using literature and TGA data. • HC-HTS improved lignin yield by 38–57 % and extractive removal by 63–85 % in comparison with HTS-only process. • HC-HTS achieved exergy efficiencies of 63–75 %, exceeding the 56–63 % range observed for the HTS-only process. • Techno-economic analysis shows positive NPV for SCB and CB, delivering an annual cash flow of roughly €1–14 M.