An investigation of thermal decomposition behavior and combustion parameter of pellets from wheat straw and additive blends by thermogravimetric analysis

This study investigates the intricate thermal decomposition behavior and combustion characteristics of two distinct types of wheat straw pellets (WSP) represented as T1 (100 % wheat straw) and T5 (70 % wheat straw; 10 % sawdust, 10 % biochar; 10 % bentonite clay). Through a thermogravimetric analyzer (TGA) the pellets undergo combustion under varying heating rates (5, 10, and 20 °C/min) in an air atmosphere, ranging from 25 to 1200 °C. Differential thermogravimetric and thermogravimetric analyses reveal four distinct stages of decomposition in the biomass components. The results indicate that the optimal combustion heating rate is 20 °C/min, resulting in the highest reaction rate (∼50 %/min) and most substantial mass loss (∼55 %) for both T1 and T5 pellets. Notably, the T5 pellet demonstrates a lower ignition temperature (207 °C, at 20 °C/min) and higher burnout (457 °C at 10 °C/min) compared to the T1 pellet, indicating its superior suitability for combustion. The combustion efficiency ranges from 61.0 to 99 % within the temperature range of 300 to 700 °C, similar to coal combustion. Additionally, thermodynamic properties (Di, Db, C, and S) suggest the promising potential of WSP as a bioenergy feedstock. Furthermore, T1 pellets demonstrate higher ignition temperatures (Ti) than T5, indicative of rapid combustion and lower energy potential. burnout temperatures (Tb) revealed intricate results in both scenarios. These findings hold significance for the design of gasification or combustion reactors and the industrial utilization of WSP biomass. The insights gathered from this study offer valuable guidance for designing and enhancing bioenergy systems and fostering sustainable practices in utilizing agricultural residues for energy production. © 2024