Chemical Kinetics and Thermodynamics Characteristic of Saudi Biomass Wastes Using Isoconversional and Independent Parallel Reaction Models

Using the TG/DTG technique, the pyrolysis and co-pyrolysis behavior and properties of biomass wastes of date kernel (DK) and fruit waste (FW) and their blends were examined at varying heating rates in an inert atmosphere. One of the main objectives of this study is to determine the activation energy (E), frequency factor (A), and reaction mechanism function (kinetic triplet). The E values were calculated for both individual and blended samples using the OFW, KAS, and ST isoconversional kinetic models. Additionally, the independent parallel reaction scheme (IPRS) with four pseudo-components is used to determine the kinetic parameters of this lignocellulosic biomass pyrolysis. The IPRS results demonstrated a high degree of agreement between modelled and experimental data. Additionally, the differences between the E values produced from IPRS and ΔH didn’t surpass 5 kJ/mole. The degradation of biomass samples was observed to match the chemical reaction mechanism (C8) model for both α = 0.1-0.5 and 0.5-0.9 ranges with high reliable values of R2, according to the master plots approach. From 200 to 400 °C at β = 30 °C /min, the synergistic impact was notable for 25 and 50% of FW in the blends; however, at β = 20 °C /min, the remarkable effect appeared for both low and high temperatures and for the entire percentage of FW. Conversely, for T < 400 °C for full percentages of FW in the blends, a substantial influence appears at β = 40 °C /min; yet, for T > 400 °C, the blends' FW concentrations of 50 and 75% exhibit noticeable effects. With an increase in heating rate (β), all pyrolysis characteristic parameters (CPI, Ddev and Rw) rose, and volatiles were produced more rapidly and steadily due to the tested samples' superior pyrolysis characteristics and stability (higher PI, Ddev and Rw).