Critical insights into pyrolysis and co-pyrolysis of poplar and eucalyptus wood sawdust: Physico-chemical characterization, kinetic triplets, reaction mechanism, and thermodynamic analysis

Critical information on physico-chemical characterization, thermo-kinetics, and thermodynamic parameters for pyrolysis of lignocellulosic biomass are vital for safe and efficient design of biomass pyrolysis reactors. In the present investigation, physico-chemical characterization, pyrolysis and co-pyrolysis kinetics, and thermodynamic analysis of poplar wood (PW), eucalyptus wood (EW), and their binary blend (MW) were studied via TGAthermograms obtained at 5, 10, and 20 degrees C/min under nitrogen atmosphere. The kinetic parameters were computed via model-fitting (inflection point and multiple linear regression) and model-free (OFW and KAS) methods. Both approaches predicted a different set of kinetic triplets where E-value from model-fitting (73.20 +/- 1.57, 55.68 +/- 1.34, 65.56 +/- 1.18 kJ/mol for PW, EW, and MW) and model-free (173.86 +/- 0.48, 210.53 +/- 0.39, and 203.47 +/- 0.23 kJ/mol for PW, EW, and MW) methods was predicted. Endothermicity, degree of stability, and energy barrier were found to be in the order of EW > MW > PW, EW > MW = PW, and EW = MW > PW, respectively. Further, behavior of pyrolysis reaction was established with the help of Criado method using Z(alpha) master plots. At initial conversion, diffusional processes predominate which was best described by D1 (1-D diffusion; Parabola law) and thereafter nuclei grew according to first- and third-order reaction models.

Automated summary

In this study, the physico-chemical characterization, pyrolysis kinetics, and thermodynamic analysis of poplar wood, eucalyptus wood, and their binary blend were investigated using TGAthermograms obtained at different heating rates. The kinetic parameters were determined using model-fitting and model-free methods, which resulted in different sets of values. The endothermicity, stability, and energy barrier were found to be different for the different materials. The behavior of the pyrolysis reaction was established using the Criado method.