화학공학소재연구정보센터
Energy Conversion and Management, Vol.182, 117-125, 2019
Pyrolysis kinetics of biomasses pretreated by gas-pressurized torrefaction
A novel gas-pressurized (GP) torrefaction method to produce torrefied biomass with high fuel quality was recently proposed in our previous work. The pyrolysis behavior and kinetics of the GP torrefied biomasses were studied in detail using DAEM, FWO and Friedman methods, and the reaction mechanism was also investigated in this work. The results showed that the Friedman method was most suitable for the pyrolysis kinetic of the torrefied biomass, compared to the DAEM and FWO methods. The pyrolysis activation energy of the GP torrefied biomass at volatilization stage was lower than those of the raw biomass and torrefied biomass produced via traditional torrefaction. Contrastingly, it increased significantly at char decomposition stage. The mechanism investigation showed that the reasons for the low activation energy at volatilization stage were the catalytic effect of the minerals, such as K and Na, and the porous structure of the GP torrefied biomass. On the other hand, the significant increase of the activation energy at char decomposition stage was mainly attributed to two factors. The first factor is that some minerals, such as SiO2, suppressed the decomposition of the char. The minerals having catalytic effect, such as K and Na, had already volatilized at high temperatures. Another contributing factor is the high aromaticity of the GP torrefied biomass. This research provides a deep understanding of the pyrolysis kinetics and mechanism of GP torrefied biomass.