Characterization of tea factory waste biomass via TGA: Pyrolysis kinetics and thermal behavior

This study investigates the pyrolysis kinetics and thermal degradation behavior of Tea Factory Waste (TFW) biomass using thermogravimetric analysis (TGA). Considering the environmental concerns associated with the disposal of large volumes of tea waste, this work explores its potential as a renewable energy feedstock. Proximate and ultimate analyses showed TFW has low moisture (5.50 %), high volatile matter (70.07 %), and low ash (3.87 %), indicating suitability for pyrolysis. The TGA experiments, conducted at various rates of heat flows of 10–30 °C/min, identified three main stages of degradation: drying, active pyrolysis, and char formation. Five model-free kinetic methodologies, Kissinger, Kissinger–Akahira–Sunose (KAS), Ozawa–Flynn–Wall (OFW), Starink, and Friedman, facilitated the determination of kinetic characteristics for pyrolysis (activation energy and pre-exponential factor) and thermodynamic characteristics (enthalpy change, change in Gibbs' free energy, and entropy change). The results provide fundamental data for optimizing TFW pyrolysis for biofuel production and developing sustainable waste-to-energy processes.