Research on the evolution characteristics of oxygen-containing functional groups during the combustion process of the torrefied corn stalk

Abstract

In this paper, the occurrence states of oxygen-containing functional groups of torrefied corn stalk and the evolution of oxygen-containing functional groups during combustion were studied. First, the combustion characteristics of torrefied corn stalk under different heating rates were measured by a thermogravimetric analyzer. Then, the combustion experiments of torrefied corn stalk at different temperatures were carried out in a tubular furnace. Qualitative and quantitative analyses of functional groups in torrefied corn stalk and char samples were performed by ATR-FTIR technology. The results show that the ignition temperature of torrefied corn stalk varied between 251 and 296 °C, and the burn-out temperature did not exceed 520 °C. In the low-temperature reaction stage, the aliphatic groups decomposed, and oxygen was absorbed by the char active sites to form an unstable C–O complex. The C–O complex further reacted to release CO and CO2. In the high-temperature stage, the aromatic groups were oxidized to form phenolic hydroxyl groups. After 450 °C, the dehydrogenation and condensation reactions of the char reduced the C–O content again.