Thermal decomposition of biomass and shallow soil mixtures

The thermal decomposition of mixtures of biomass and shallow soil supports the development of wildland fire. However, the interaction between biomass and shallow soil has been scarcely studied. In this work, the thermal behaviors of pine needle, pine bark, pine branch, shallow soil, and their mixtures are investigated by using thermogravimetric analyses under nitrogen and air atmospheres. A quantitative method, based on two parameters that reflect the deviation between the experimental and mass-weighted curves of a mixture, is applied to evaluate the influence of interaction on the organic and inorganic components. The mass-weighted curves are obtained by the superposition of experimental data of single materials. The results confirm an insignificant effect of interactions between biomass and shallow soil on pyrolysis and combustion. A kinetic model, consisting of nth-order independent parallel reactions, is applied to simulate the thermal decomposition of pure and mixed samples.