Torrefaction thermal process is a promising technology being advanced for biomass solid fuel upgrading. Searching for technological improvements, potassium biomass impregnation shows a catalytic effect in biomass thermochemical conversion. This work continues a study on potassium's catalytic effect on torrefaction behaviors and condensable compound yields. In the present work, the thermal degradation kinetics of Eucalyptus hybrid clonehardwood impregnated with three different concentrations of K2CO3 was assessed. A validated thermal sensitive two-step reaction model based on four kinetic rate constants was fulfilled with experimental data of torrefaction treatment under inert conditions for the numerical modeling. The weight loss was predicted using the same activation energies but different pre-exponential factors in determining the kinetic rates. The kinetics simulation is in good agreement with experimental results and literature comparison, indicating faster reaction rates for second step reactions due to the potassium impregnation.