Bioenergy Potential of Salix alba Assessed Through Kinetics and Thermodynamic Analyses

Abstract

Reutilizing the shavings of willow wood (Salix alba), a waste biomass from cricket bat manufacturing units of Kashmir (India) through pyrolysis, would prove to be a promising way for bioenergy production. The thermal degradation of this waste biomass was carried out under inert atmosphere using thermogravimetric analysis (TGA), at three different heating rates of 10, 25, and 50 K min−1. The kinetic and thermodynamic analyses were performed using isoconversional models of Kissenger-Akahira-Sunrose (KAS) and Ozawa-Flynn-Wall (OFW). The heating value of the willow wood shavings was found to be 18.03 MJ kg−1. The values of activation energy were found to be in the range of around 41.5 to 167.8 kJ mol−1 through conversion points of 0.2 to 0.8. The average value of change in Gibbs free energy were calculated to be of the order of 183.2 and 182 kJ mol−1 using KAS and OFW models, respectively. The thermal degradation reaction mechanism was predicted using Coats-Redfern method which showed that the one-dimensional diffusion model and first-order kinetic reaction model were best suited to represent the degradation process involving both exothermic and endothermic reactions. The thermodynamic parameters including pre-exponential factor, changes in enthalpy, and entropy reflect an enormous potential of the Salix alba shavings as low-cost waste biomass for bioenergy production.