Thermochemical Conversion of Sugarcane Bagasse: Composition, Reaction Kinetics, and Characterisation of By-Products

Sugarcane bagasse pyrolysis is an effective way of producing renewable and sustainable energy. A combined study on characterisation of primary and secondary by-products of sugarcane towards the effective use of bagasse as an energy feedstock and biochar is not yet available in the existing literature. This study is an attempt to bridge this gap and to understand the complete valorisation potential of sugarcane bagasse and its by-products. In this study, the elemental, structural, and compositional analyses of sugarcane bagasse collected from various sources were carried out, and their thermal decomposition behaviour under pyrolysis conditions was investigated using thermogravimetric data. The composition of all sugarcane bagasse samples showed remarkable similarity, except for the presence of high soluble sugars in two of the six samples. The hemicellulose content in the lignocellulosic bagasse samples was found to have a distinct thermal decomposition pattern, resulting in deconvolved derivative thermogravimetric curves with peaks centred at around 300 °C. A detailed analysis of the thermogravimetric data indicated a complex multi-step thermal degradation behaviour for bagasse under pyrolysis conditions. The pyrolysis reaction kinetics of sugarcane bagasse were developed by using iso-conversional and model-fitting methods. Further, SEM–EDS analysis revealed that the biochar obtained from bagasse fast pyrolysis experiments was predominantly siliceous. X-ray diffraction studies on biochar indicated that there were no crystalline phases, even at pyrolysis temperature of 700 °C.