Study of reactivity reduction in sugarcane bagasse as consequence of a torrefaction process

Abstract

A complete study of torrefaction process to sugarcane bagasse under different thermal conditions was developed. After torrefaction process, chars were burned in an oxidizing atmosphere and its reactivities were studied. The torrefied biomass was characterized through chemical and physical analysis such as proximate and elemental analyses, lignocellulosic composition, High Heating Value (HHV), Fourier Transform Infrared Spectroscopy (FTIR) and observations in Scanning Electron Microscopy (SEM). The torrefied biomass was also evaluated in oxidizing conditions in order to analyze the impact of torrefaction process over biomass combustion process. Remarkable changes of the main functional groups were observed as the severity of the torrefaction process increased. The main structural carbohydrates affected in the process were hemicellulose and cellulose, which break down largely as a result of decarboxylation reactions, and breakage of links with methyl and acetyl groups. This was evidenced qualitatively when the material was observed in SEM, an increase in the decomposition of the cell wall structures as the process temperature increased was noted. These changes in the material were also verified with FTIR tests, and lignified matrix with higher content of aromatic groups and greater thermal stability is yielded with temperature increases.