Kinetic study of thermal decomposition of sugarcane bagasse pseudo-components at typical pretreatment conditions: Simulations of opportunities towards the establishment of a feasible primary biorefining

A deeper understanding of the kinetic and thermodynamic parameters of thermal degradation of sugarcane bagasse (SCB) is fundamental to defining appropriate conditions for primary biorefining in the production of renewable fuels. In this work, the kinetics of thermal degradation of high polymers of SCB was investigated through thermogravimetric data. Model-free and model-fitting methods were used to calculate apparent activation energies (E_a) and other related reaction parameters. An essential advance of this work is related to the quantitative interpretation of the degradation process (an endothermic and non-spontaneous process) via a multi-stage model governed by diffusion-controlled reactions and order-based models, which helps explain the differences observed in the mass balance of biorefining processes. Based on derivative thermogravimetric curves, three major peaks were associated with pseudo-components (PSE): PSE 1 (hemicelluloses + extractives and lignin), PSE 2 (cellulose + extractives and lignin), and PSE 3 (lignin + extractives and residual holocellulose). For PSE 1, PSE 2, and PSE 3, respectively, E_a ranges of 124–154, 147–153, and 230–530 kJ⋅mol⁻¹ were obtained using the Kissinger-Akahira-Sunose method, and 120–152, 144–150, and 232–545 kJ⋅mol⁻¹ were obtained using the Flynn-Wall-Ozawa method. These data support the calculation of many critical operating parameters of biorefinery processes, such as the minimum pretreatment temperature. SCB biorefining could lead to a degradation of up to 10, 0.5, and 11% of PSE 1, PSE 2, and PSE 3, respectively, at 473.15 K for 200 min.