Investigation on prospective bioenergy from pyrolysis of butia seed waste using TGA-FTIR: Assessment of kinetic triplet, thermodynamic parameters and evolved volatiles

Abstract

The pyrolysis of butia seed waste (BSW) was investigated under a thermogravimetric scale at multiples heating rates (5–40 °C min−1) in a nitrogen atmosphere. First, the pyrolysis behavior of BSW was deconvoluted into four independent reactions using the Asym2Sig fitting function. The kinetic triplets (activation energies, pre-exponential factors, and reaction models) were acquired using four isoconversional methods, the compensation effect method and the master plot method. The kinetic parameters estimated were in the range of 111.5–190.9 kJ mol−1 for the average activation energy and 1.55 × 1010–2.89 × 1014 min−1 for the pre-exponential factor. According to the master plot method, the pyrolysis of BSW is described by the summative effect of geometrical contraction and n-order reaction mechanisms. A multi-component kinetic approach was suitable for capturing the complexity involved in the pyrolysis of BSW, with a coefficient of determination (R2) > 0.95 and quality of fit (QOF) > 93%. Pyrolytic conversion of BSW into biofuels is characterized by an endothermic nature (ΔH > 0) and low reactivity (ΔS < 0). The volatile products evolved from the pyrolytic decomposition of BSW were characterized using the integrated TGA-FTIR system, which confirmed the presence of high-energy compounds (aromatics) and useful chemicals (aldehyde, ketone, esters, ether, and alcohols).