Kinetic analysis and modeling of maize straw hydrochar combustion using a multi-Gaussian-distributed activation energy model

Combustion kinetics of the hydrochar was investigated using a multi-Gaussian-distributed activation energy model (DAEM) to expand the knowledge on the combustion mechanisms. The results demonstrated that the kinetic parameters calculated by the multi-Gaussian-DAEM accurately represented the experimental conversion rate curves. Overall, the feedstock combustion could be divided into four stages: the decomposition of hemicellulose, cellulose, lignin, and char combustion. The hydrochar combustion could in turn be divided into three stages: the combustion of cellulose, lignin, and char. The mean activation energy ranges obtained for the cellulose, lignin, and char were 273.7–292.8, 315.1–334.5, and 354.4–370 kJ/mol, respectively, with the standard deviations of 2.1–23.1, 9.5–27.4, and 12.1–22.9 kJ/mol, respectively. The cellulose and lignin contents first increased and then decreased with increasing hydrothermal carbonization (HTC) temperature, while the mass fraction of char gradually increased.