Assessing the Bioenergy Potential of Peanut Shell Waste: High Heating Rate Combustion Behavior and Thermodynamic...

Area of Science:

• Biomass energy conversion
• Thermochemical processing of biomass
• Sustainable biofuels

Background:

• Agricultural residues like peanut shells (PnS) are abundant but underutilized biomass resources.
• Evaluating PnS combustion properties is crucial for developing sustainable solid biofuels.
• Understanding PnS thermochemical behavior informs its efficient energy conversion.

Purpose of the Study:

• To comprehensively analyze the combustion behavior and kinetics of peanut shell (PnS).
• To assess the potential of PnS as a sustainable solid biofuel.
• To elucidate the reaction mechanisms governing PnS thermal decomposition.

Main Methods:

• Physicochemical characterization: proximate, ultimate, Van Soest, and FTIR analysis.
• Non-isothermal thermogravimetric analysis (TGA) at high heating rates (20–80 K min⁻¹).
• Model-free (Friedman, FWO, KAS, Starink, Kissinger, Vyazovkin) and model-fitting (Coats-Redfern) kinetic analyses.

Main Results:

• PnS exhibits high volatile matter (65.30 wt%) and heating value (20.87 MJ kg⁻¹), surpassing many agricultural residues.
• TGA showed distinct decomposition stages, with primary devolatilization between 500–700 K.
• Kinetic analysis indicated variable activation energy (23–187 kJ mol⁻¹) and identified the 3D diffusion (D3) model as the governing mechanism.

Conclusions:

• PnS is a promising sustainable solid biofuel candidate due to its favorable combustion characteristics.
• The lignocellulosic matrix degradation is complex, governed by diffusion-controlled processes.
• The endothermic and non-spontaneous nature of PnS combustion activation was confirmed thermodynamically.