Assessment of thermal behavior and pyrolytic kinetics of selected agro-residues through thermogravimetric analysis

Abstract The physicochemical characteristics and kinetics of sugarcane bagasse (SCB) and black gram straw (BGS) have been studied using a thermogravimetric analyzer under nitrogen atmosphere at 20°C/min heating rates. The analysis showed that SCB has higher volatile matter (81.32 wt.%), lower ash (3.50 wt%), and moisture content (5.36 wt%) while significantly higher HHV (18.10 MJ/ kg). The TG and DTG curves displayed four significant zones mainly attributed to moisture removal, decomposition of hemicellulose and cellulose, and lignin, respectively. The Coats-Redfern model fitting method was used to determine the kinetic and thermodynamic parameters of the active pyrolysis zone. The activation energies of SCB and BGS were 88.74 and 96.74 kJ/mol, respectively. The following thermodynamic parameters were found: change in enthalpy is 83.65 and 92.14 kJ/mol, Gibbs free energy is 126.64 and 144.69 kJ/mol, and change in entropy is -73.29 and − 94.92 J/mol.K, for SCB and BGS, respectively. These physicochemical properties and kinetic parameters confirm that SCB and BGS are promising feedstocks for pyrolysis.