Exploring Açaí Seed (Euterpe oleracea) Pyrolysis Using Multi-component Kinetics and Thermodynamics Assessment Towards Its Bioenergy Potential

Abstract

The novelty of this study is that it presents the first in-depth evaluation of the kinetic triplet and thermodynamic parameters from the pyrolysis of acai seed (Euterpe oleracea), which is the main biowaste from the acai fruit processing industry. First, the physicochemical characteristics of the acai seed, i.e., the proximate analysis, ultimate analysis, energy content, bulk density, and bioenergy density, were determined. Thermogravimetric experiments were then conducted to evaluate the pyrolysis characteristics of the acai seed, the kinetic triplet (Ea, A, and f(α)), and the thermodynamic parameters (ΔH, ΔS, and ΔG). Three pseudo-components were distinguished from the acai seed pyrolysis profile using the asymmetric double sigmoidal (Asym2sig) function, which was described by the reaction model for the first order, third order, and eighth order, respectively. The Vyazovkin isoconversional method showed values of Ea ranging from 103 to 346 kJ mol−1 for acai seed pyrolysis. The kinetic expression was applied to reconstruct the experimental data used (R2 > 0.9210) for the kinetic study and validated with a different experimental condition. The statistical test indicated no significant difference between experimental and calculated curves; therefore, the kinetic parameters are applicable to different thermal conditions. Physicochemical properties and thermodynamic parameters suggested that the acai seed is a good candidate for bioenergy conversion through pyrolysis. Acai seed is a promising feedstock for bioenergy production, as demonstrated by the kinetic and thermodynamic findings, and this information is important for advancing the design and scale-up of an acai seed pyrolysis process.