Pyrolysis kinetics and thermodynamic behavior of pseudo components of raw and torrefied maple wood

In this work, pyrolysis kinetics and thermodynamic behavior of pseudo components (PCs) of raw and torrefied maple wood (MW) were studied. The MW torrefaction experiments were conducted at 240degree celsius and the pyrolysis process was performed under three distinct heating rates. Through the deconvolution procedure, three PCs, i.e. pseudo-hemicellulose (PC-HC), pseudo-cellulose (PC-CL), and pseudo-lignin (PC-LG), were identified. The activation energy (E-alpha) of PCs were evaluated using the Starink method, and the pyrolysis reaction mechanisms were analyzed using the Criado's master plot method. Furthermore, three thermodynamic parameters were also calculated and discussed. Results showed that after torrefaction, the PC-HC content dropped from 47.30% to 7.90%, while the PC-CL and PC-LG contents increased from 33.67% to 55.72% and from 19.03% to 36.38%, respectively. The average E-alpha of raw MW PC-HC, PC-CL and PC-LG were 114.56, 117.12 and 116.02 kJ/mol, respectively, whereas they were 92.86, 103.82 and 159.26 kJ/mol for torrefied PCs, respectively. The master plot results suggested that the pyrolysis of MW PCs involved different order-based models. In addition, the thermodynamic analysis revealed that the torrefied PC-HC required slightly less heat energy during pyrolysis. All these observations can be conducive to better understand the pyrolysis mechanisms of raw and torrefied MW PCs. [GRAPHICS] .