Chacón-Parra, A.van Eyk, P.2025-08-062025-08-062022Fuel: the science and technology of fuel and energy, 2022; 309:122169-1-122169-80016-23611873-7153https://hdl.handle.net/2440/146563Hydrothermal carbonisation (HTC) of biomass has gained attention in recent years due to its potential applications in functional sustainable materials. Cellulose as the most abundant organic polymer on earth and a key component of multiple biomass sources has been extensively studied, and it is widely accepted that glucose is the major product of the polysaccharide’s hydrolysis above 200 ◦C. However, differences observed in the hydrochar produced from the HTC of cellulose and glucose have suggested that a direct reaction takes place in the polysaccharide’s conversion. In the present study, a solid-state reaction pathway for the HTC of cellulose is elucidated using reaction kinetics modelling and optimisation in a progressive reaction mechanistic and the effect of temperature on reaction selectivity is analysed. The experiments were conducted with glucose and cellulose in a batch reactor with 20% mass feedstock at 220 ◦C, 240 ◦C and 260 ◦C, over a residence time distribution. And the kinetic parameters were established by fitting the experimental data with a series of reaction mechanism and kinetic models via multivariable optimisation. Whilst the activation energy for the hydrochar formation reaction from glucose was 46.6 kJ/mol, the same reaction from cellulose, assuming complete hydrolysis, produced a value three times bigger. Therefore, a composite cellulose model, in which hydrochar through soluble intermediates, is restricted to the glucose reaction constant and balanced with a direct solid-state reaction pathway, produced activation energies of 210.8 kJ/mol for hydrolysis of cellulose and 207.3 kJ/mol for the solid-state reaction.en© 2021 Elsevier Ltd. All rights reserved.Hydrothermal carbonisation; Reaction kinetics; Cellulose; Glucose; Hydrolysis; Solid-state reactionJournal article10.1016/j.fuel.2021.122169591740van Eyk, P. [0000-0003-3768-2044]