Kinetics and thermodynamic study of Calligonum polygonoides pyrolysis using model-free methods

Pyrolysis kinetics was carried out for Calligonum polygonoides (C. Polygonoides) in an inert atmosphere at three different heating temperatures such as 10, 15, and 20 °C/min using thermogravimetric analysis. Physicochemical properties were studied using bomb calorimeter, elemental analyzer, and Fourier Transform Infrared Spectroscopy. C. Polygonoides have a calorific value of 16.33 MJ/kg. Gas chromatography–mass spectrometry was used to identify gases produced during pyrolysis. Thermogravimetric analysis was used to investigate the pyrolysis characteristics of biomass. Activation energy for the three zones of pyrolysis were determined using Kissinger and Ozawa model-free methods. Activation energy calculated for zone I, zone II and zone III using Ozawa and Kissinger model was 133.73, 164.50, 254 KJ/mol and 135.61, 165.88, and 253.00 KJ/mol, respectively. Thermodynamic parameters such as enthalpy, entropy, and Gibbs free energy were calculated for the three different zones. Kinetic and thermodynamic study confirmed that C. Polygonoides can be used as useful and potential bioenergy feedstock.