Linking Chemical Composition to Thermal Decomposition of Lignocellulosic Biomass and Its Structural Fractions: Insights from Eucalyptus and Sugarcane Bagasse

Abstract

Lignocellulosic biomass is considered a promising alternative to fossil fuels. Due to its complex composition, understanding its thermal behavior is essential for improving the energy efficiency of thermochemical conversion processes. Thermogravimetric analysis has been widely used to investigate biomass thermal behavior; however, available studies are generally fragmented across different materials and experimental conditions, limiting direct comparisons. Therefore, this study provides a systematic comparison of eucalyptus wood and sugarcane bagasse, together with their structural fractions, under identical thermogravimetric conditions. This study investigates the thermal decomposition behavior of eucalyptus wood chips and sugarcane bagasse, as well as their structural components─cellulose, hemicellulose, and lignin─to better understand biomass pyrolysis processes. Proximate and chemical analyses were conducted to characterize the biomass and isolate its structural fractions, followed by thermogravimetric (TG/DTG) analysis. In addition, DTG curve deconvolution was performed to quantitatively evaluate overlapping degradation events. In general, eucalyptus and sugarcane bagasse exhibited similar TG and DTG profiles under equivalent conditions, including the in natura biomass and samples after sequential removal of extractives, hemicellulose (holocellulose), and α-cellulose. However, a gradual disappearance of the shoulder peak (Tsh) preceding the maximum decomposition temperature, together with a narrowing of the main DTG peak, was observed after the sequential removal of structural components, indicating the influence of extractives and hemicellulose on thermal decomposition. Deconvolution analysis quantitatively confirmed the contribution of these overlapping thermal events. These results establish a direct relationship between chemical composition and thermal behavior under standardized conditions. The comparative evaluation of biomass and its structural fractions, complemented by DTG curve deconvolution, provides quantitative information that improves the interpretation of thermal degradation events and supports the development of thermochemical conversion technologies for bioenergy applications.