Su, Zi-ChengZi-ChengSuChen, Yi-MingYi-MingChenBOR-YIH YU2026-03-122026-03-122026-03-0109575820https://www.scopus.com/record/display.uri?eid=2-s2.0-105027975931&origin=resultslisthttps://scholars.lib.ntu.edu.tw/handle/123456789/736234Hydrothermal carbonization (HTC) is a promising technology for converting lignin into biochar. However, significant research gaps remain in modeling this process due to the complex reaction mechanisms, lack of reliable macroscopic kinetic models, and challenges in product identification. For the first time, this study develops a comprehensive framework to evaluate lignin HTC through rigorous modeling, covering model compound selection, reaction pathway development, thermodynamic modeling, process design and optimization, and integrated life cycle assessment (LCA) and techno-economic analysis (TEA). The LCA study underscores the critical role of impact allocation in the pretreatment of lignin. Two allocation scenarios show negative global warming potential (GWP): Scenario 1, employing mass allocation, exhibited a GWP of −2.05 kg-CO2eq/kg-biochar, while Scenario 2, utilizing benefit allocation, showed a GWP of −2.49 kg-CO2eq/kg-biochar. In contrast, Scenario 3, based on main product allocation, resulted in a net positive emission of + 1.87 kg-CO2eq/kg-biochar. In contrast, TEA determines the minimum selling price (MSP) at 1.42 USD/kg-biochar. Integrated LCA and TEA suggest that under high carbon pricing, MSP for carbon-negative scenarios could approach zero. It indicates that producing biochar for CO2 removal is likely to be profitable. Overall, this study presents an effective framework that enables comprehensive and rigorous evaluation of the HTC process of lignin.falseBiocharHydrothermal carbonizationLife cycle assessmentLigninProcess designTechno-economic analysisjournal article10.1016/j.psep.2026.1084422-s2.0-105027975931