Overriding Investigation on Strengthening of Thermal Stability of Torrefied Pigeon Pea Stalk and Kinetic Compensation

Abstract

This article aims to evaluate the pyrolytic behavior of torrefied biomass in order to resolve the logistic issue of the biomaterial and utilize it during idle time. In order to that, the thermal treatment of the raw pigeon pea stalk was done up to 250℃ in a reactor in an inert environment. The obtained solid biomaterial was subjected to the thermogravimetric analysis for four various heating rates (10, 20, 30, and 40℃/min) to investigate the changes occurring in thermal behaviour and kinetic parameters over the raw material. The deconvolution analysis of the thermogravimetric signals leads the study to an overriding investigation on thermal stability of the intrinsic bioconstituent. In addition, the kinetic triplet and thermodynamic parameters were estimated by employing the ICTAC recommended Ozawa-Flynn-Wall isoconversional method. The computed average activation energy level of the torrefied biomaterial (229 kJ/mol) was registered significantly higher than the raw pigeon pea stalk (139 kJ/mol). Also, the changes registered in thermodynamic parameters such as ΔG, ΔH and ΔS give a beneficial sign on the thermal stability of the existing bioconstituents. Torrefaction of the pigeon pea stalk enhances the kinetics and thermodynamic balancing of the biomaterial. The thermally established biomaterial can be stored for a longer period and it can utilize as the bioenergy generating feedstock during idle periods.