Enhanced Bio-Oil Yield from Thermal Decomposition of Peanut Shells Using Termite Hill as the Catalyst

This study focused on the thermal degradation of peanut shells in the presence and absence of a termite hill as the catalyst. EDX, XRF, SEM, SAA and XRD were employed for the characterization of the termite hill. The bio-oil obtained from peanut shell pyrolysis was analyzed by GC-MS. To ascertain the kinetic parameters of the reaction, thermogravimetric analysis of peanut shells was carried out with and without a termite hill at heating rates of 3, 12, 20 and 30^◦C·min⁻¹ . TG/DTG of peanut shells revealed four steps of weight loss from 30 to 800^◦C. The weight loss was attributed to the evaporation of water and degradation of hemicellulose, cellulose and lignin. The Kissinger method was applied for the evaluation of kinetic parameters. The activation energy (E) for the non-catalyzed degradation reactions of hemicellulose, cellulose and lignin was evaluated as 108.082, 116.396 and 182.908 kJ/mol, with a pre-exponential factor (A) of 1.9 × 10⁸, 2.42 × 10⁹ and 2.98 × 10¹¹ min⁻¹, respectively. Similarly, for the catalyzed reaction, the values of E and A were calculated as 66.512, 74.826 and 133.024 kJ/mol and 5.83 × 10⁶, 2.859 × 10⁷ and 1.46 × 10⁹ min⁻¹, respectively. The termite hill not only reduced the degradation temperature and activation energy but also modified the composition of the bio-oil. In the case of the non-catalyzed reaction, the bio-oil was found to consist of C₅-C₂₄, while catalytic pyrolysis produced more components ranging from C₄ to C₃₁ hydrocarbons.