Thermal Behavior of Woody Biomass in a Low Oxygen Atmosphere Using Macro-Thermogravimetric Analysis

37 Abstract— This work focused on investigating the thermal behavior of the coniferous tree (beech) and broadleaf tree (beefwood) that are abundantly available in Vietnam during a low-oxygen combustion condition. Pyrolysis in 100% Nitrogen atmosphere, char oxidation and combustion in 3% Oxygen atmosphere were conducted using a Macrothermogravimetric analyzer, from room temperature to 900C. Results showed that, regarding pyrolysis and char oxidation processes, beech biomass has the initial mass loss and the maximum mass loss at higher temperatures compared to beefwood biomass. For the overall combustion process, two stages could be clearly observed in differential thermal analysis curves, which correspond to devolatilization and char oxidation. However, the maximum combustion rate temperature and the char burnout temperature were sharply lower than in the case of pyrolysis and char oxidation that were carried out independently. This is likely due to volatile combustion of gaseous products released in devolatilization that could lead to an increase of the particle temperature and an acceleration of the pyrolysis and char oxidation kinetics. This highlighted the synergistic effects of pyrolysis and char oxidation in the overall combustion process. Results of this study could contribute to the understanding of the combustion profile of these kinds of biomass in a low oxygen atmosphere, in order to better organize the furnace combustion and effectively improve the efficiency of coal/biomass combustion.