BIOMASS CONVERSION AND BIOREFINERY, cilt.14, sa.24, ss.32427-32452, 2024 (SCI-Expanded)
The study investigates thermal degradation behaviors of pistachio (PS), almond (AS), walnut (WS), and hazelnut (HS) shells that are vegetal biomass sources using thermogravimetric analysis (TGA/DTG) methods and under high temperatures. The study was conducted in nitrogen at 298-1173 K heat intervals, at 5, 10, 20, and 25 K.min-1 heating rates. Using data achieved as a result of thermal characterization procedures, model-free Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), and model-based Coats-Redfern (CR) methods are used to investigate kinetic and thermodynamic parameters including Ea, Delta H, Delta S, Delta G, and pyrolysis reaction mechanism. Two regions in (0.1 <= alpha <= 0.5) and (0.55 <= alpha <= 0.9) intervals are created based on the change of Ea values of pistachio, almond, and hazelnut shells based on alpha. The best model in Region I was determined to be one of the diffusion (D) models while in Region II, it was determined to be one of the nth-degree chemical reaction (F) models.