In-depth physiochemical characterization and detailed thermo-kinetic study of biomass wastes to analyze its energy potential

Abstract

The present work focuses on to determine the feasibility of alternate energy generation from waste biomass as a feedstock. Five different wastes namely coconut shell, corn cob, sugarcane bagasse, Shorea Robusta and Citrus limetta have been thoroughly characterized to analyze their energy potential. Coconut shell with highest heating value of 16.8 MJ/kg among all the samples and bulk density of 590.85 kg/m3 has been selected for further detailed kinetic analysis. Highest overall volatile conversion of 57.17% is obtained in the active zone for heating rate 40 °C/min. Different differential and integral based models have been discussed and implemented for the calculation of activation energy and its average value for coconut shell sample is found to be 109.90 kJ/mol with pre-exponential factor as 4.37х109 s−1. Moreover, the reaction model was predicted by comparing various theoretical and experimental z (α) master plots. Also, the model fitting method is also used to obtain the reaction model f(α) = (1-α)4.6654 [-ln (1-α)]−0.2 which shows order based nucleation mechanism. Change in enthalpy, entropy and Gibbs free energy has also been determined to access the thermodynamic stability of the system. The kinetic parameters and thermodynamic results suggest highly reactive system initially which decreases with the extent of conversion.