Investigation of kinetic and thermodynamic parameters for pyrolysis of peanut shell using thermogravimetric analysis

The aim of the present study is to explore the thermal degradation behaviour and investigate the kinetic and thermodynamic parameters for pyrolysis of peanut shell (PS). Proximate, ultimate composition and calorific value of PS were employed to determine the energy potential of PS. Pyrolysis tests were performed in a thermogravimetric analyzer at heating rates of 10, 20 and 30 °C/min in inert (N2) atmosphere. Thermal analysis of PS confirms that the thermal degradation of PS occurred in three stages and major weight loss found in 200 to 600 °C. The pyrolysis kinetic parameters (activation energy and pre-exponential factor) and thermodynamic parameters (changes in enthalpy, Gibb’s free energy and entropy) were determined by Ozawa-Flynn-Wall (OFW), Kissinger, Kissinger-Akahira-Sunose (KAS) and Coats-Redfern methods. The value of activation energy (Ea) evaluated by the Kissinger method was 109.05 kJ/mol, while the average Ea calculated by OFW and KAS was 109.94 and 96.93 kJ/mol, respectively. Result showed that the Ea varies with the degree of conversion. The pre-exponential factors were obtained in the range of 2.99 × 1012–7 × 1013 min−1, increased with the rate of heating and decreased with conversion. The results of this study suggest that PS has potential to be used as a pyrolysis feedstock.