This work, led by an early-career researcher, investigates the pyrolysis behavior and kinetic modeling of high ash fraction loblolly pine (HAF-LP), kaolin clay (KC), and their binary mixtures (25:75, 50:50, 75:25) under inert nitrogen conditions to support the development of sustainable thermal conversion pathways. Using thermogravimetric analysis (TGA) across three heating rates (5, 10, and 20 K/min) and nitrogen flow rates (10, 20, and 30 mL/min), the study evaluates the influence of thermal and transport parameters on degradation kinetics. Model-free kinetic approaches—including Kissinger, Ozawa-Flynn-Wall (OFW), and Kissinger-Akahira-Sunose (KAS)—were used to quantify activation energies and conversion-dependent behavior. Results showed that pure HAF-LP followed a first-order reaction mechanism, while KC degradation adhered to a third-order (F3) pathway. The composite samples exhibited synergistic degradation patterns, with KC increasing thermal stability and shifting decomposition to higher temperatures. Across the N₂ gas tests, it was observed that increasing inert gas flow rate (from 10 to 30 mL/min) resulted in reduced mass loss at all heating rates, while lower flow rates enhanced devolatilization, particularly at lower heat rates. DTG curves indicated that higher N₂ flow delayed DTG peak temperatures, with consistently lower mass loss rates compared to lower flow conditions. The DDTG analysis further confirmed that higher N₂ flow slightly extended the burn-off duration, especially at 20 K/min, suggesting a cooling effect from increased purge velocity. These interactions suggest a non-additive, hybrid kinetic behavior valuable for process modeling and reactor design. The findings offer critical insights for optimizing hybrid biomass-inorganic systems for low-carbon energy generation, including in fixed-bed and fluidized-bed pyrolyzers. This early-stage research lays the foundation for scalable, sustainable bioenergy technologies that leverage waste biomass and mineral additives, contributing to circular and carbon-conscious thermal systems.
