Determination of thermal decomposition kinetics of low grade coal employing thermogravimetric analysis

Thermal decomposition kinetics of Prosopis juliflora charcoal briquette using thermogravimetric analysis

In the current study, the energy potential of Prosopis juliflora charcoal briquette sample was assessed using thermogravimetric analysis at heating rates 10 °C/min, 15 °C/min, and 20 °C/min under nitrogen atmosphere. The thermogravimetric study showed that the thermal devolatilization of the briquette sample occurred in four principal stages. The major degradation of the sample occurred in the fourth stage indicating that the significant mass loss occurred due to the fixed carbon that was abundant in the briquette sample. The activation energy was determined by employing five different model-free methods. The average activation energy attained for the briquette sample by Kissinger-Akahira-Sunose method, Flynn-Wall-Ozawa method, Tang method, Starink method, and Friedman method was 83.55 kJ/mol, 91.60 kJ/mol, 79.91 kJ/mol, 80.06 kJ/mol, and 96.74 kJ/mol, respectively. The frequency factor obtained in the study ranged between 1.42 × 10³ and 6.23 × 10⁷ min^-1. The contracting sphere model was found to be closely related to the reaction model obtained for charcoal briquettes. The lower activation energy and frequency factor indicated rapid thermal degradation of the charcoal briquettes. The estimated thermodynamic parameters indicated that the thermal degradation process was endothermic in nature.