Inner-particle reaction mechanism of cellulose, hemicellulose and lignin during photo-thermal pyrolysis process: Evolution characteristics of free radicals.

Based on the concentrated photo-thermal thermogravimetry analyzer (PT-TGA) reactor, the pyrolysis of the cellulose, hemicellulose and lignin with different ratios at 100 °C/min and 550–850 °C was performed. The interaction among the three components significantly reduced the reaction temperatures and increased the maximum weight loss rate. The cellulose/lignin interactions were the main reason for the increase of gas production, especially for the H 2 production which reached 128.13 mL/g biomass, much higher than the calculated value of 75.35 mL/g biomass without considering the interactions. What occurred during the co-pyrolysis of cellulose/lignin was the combination of free radicals without consuming the hydrogen radicals, while the formation of chemicals in others' interactions integrated with the hydrogen radicals inhibited the production of H 2 at high temperatures. For full-component pyrolysis, the yield of C-containing gas can be calculated by adding a coefficient of interaction between two components, indicating that the effect of the three-component interaction was much lower than that of the two-component. This study established the interaction mechanism for the three components of biomass during photo-thermal pyrolysis based on free radicals. [Display omitted] • Inner-particle reaction significantly accelerated the fast pyrolysis process. • C-containing gases of components mixed in different ratios could be predicted. • Radicals from hemicellulose only promoted C-containing gas yields before 650 °C. • The combination of radicals from cellulose/lignin enhanced the production of H 2. [ABSTRACT FROM AUTHOR]