Amazonian forest residues as bioenergy resources: pyrolysis behavior, kinetic triplets and model validation

Abstract

Wood residues from sustainable forest management in the Amazon represent an underexploited feedstock for thermochemical conversion, yet the pyrolysis kinetics of these materials remain poorly characterized. Eleven native Amazonian species were physicochemically characterized and grouped by cluster analysis into five classes with distinct lignocellulosic and energy profiles; one species per cluster ( Pourouma spp., Nectandra cf. amazonum , Dinizia excelsa , Caryocar glabrum , and Pouteria cf. oblanceolata ), selected to span the physicochemical diversity identified among the eleven species, was subjected to kinetic study. Non-isothermal thermogravimetric analyses were performed under nitrogen at five heating rates (2.5–20 K min −1 ), and kinetic triplets were determined using isoconversional methods (FDM, FWO, KAS, STK, VZK) combined with the kinetic compensation effect. Average apparent activation energies ranged from 156.31 to 172.27 kJ mol −1 , with the lowest and highest values associated with the holocellulose and lignin/extractive-richest biomasses, respectively, and global pre-exponential factors on the order of 10 10 –10 11 s −1 . The two- and one-dimensional diffusion models (D2 and D1) best described the devolatilization behavior of the five residues. Reconstruction of the experimental curves validated the estimated kinetic triplets, with mean percentage deviations below 1% for conversion and below 10% for conversion rate across all heating rates. These results link chemical composition to pyrolysis reactivity in Amazonian hardwood residues and provide a kinetic dataset for subsequent the design, simulation, and scale-up of thermochemical conversion routes for their energy valorization.