Abstract
The combustion properties of biomass can be improved via torrefaction. In this work, the effect of torrefaction on combustion properties of pine sawdust (PS) was investigated. The torrefaction conditions for PS were at 523 K for 40 min and 551 K for 15 min, respectively. Raw pine sawdust (RPS) and torrefied pine sawdusts (TPS) were selected to undergo combustion in a thermogravimetric analyzer at four different heating rates. Pretreatment by torrefaction reduced the temperature range of TPS during the volatile release process. A non-isothermal thermogravimetric method was used to evaluate the combustion kinetics through a model-free method. The activation energy analysis based on the Flynn–Wall–Ozawa method showed that the decomposition of more hemicellulose in the torrefaction process contributed to the higher activation energy in the early stage of TPS combustion process. The reaction order was calculated by the Avrami theory, and the results indicated that the least thermally stable sample TPS551-15 had the highest reaction order.
