Thermal degradation behaviors of sawdust wood waste: pyrolysis kinetic and mechanism

In this study, the thermal behavior of sawdust wood (SW) wastes samples was examined at different heating rates (β) ranging from 2 to 15 °C/min in inert atmosphere using the technique of thermogravimetric analysis (TGA). As the increment of heating rates, the variations of characteristic parameters from the TG-DTG curves were determined. Eight methods: Friedman (FR), Ozawa-Flynn-Wall (OFW), Vyazovkin (VYA), Kissinger- Akahira-Sunose (KAS), Starink method (ST), Avrami theory (AT), Coats-Redfern and Criado methods were used in this work to evaluate the kinetic parameters, including apparent activation energy (Ex), reaction order (n) and the appropriate conversion model f(x). For the range of conversion degree (x) investigated (20 – 80 %), the mean values of apparent activation energy for Sawdust wood waste were 168 KJ/mol, 153 KJ/mol and 164 KJ/mol for FR, OFW and VYA methods respectively. While for KAS and ST methods were 158 KJ/mol and 156 KJ/mol. With varied temperature (300-700 °C), the corresponding values of reaction order (n) was increased from 0.1072 to 0.2587, along with a decrease to 0.1635. The pyrolysis model f(x) of SW is described by reaction order (Fn), first order (F1) for the degradation of the studied wastes samples.