Two-Step Kinetic Models For Thermal Decomposition Of Forest Combustibles: Three Kinetic Schemes

In fire research, simplified kinetic models of thermal decomposition of charring combustibles with high simulation accuracy are of great importance in modelling of solid ignition and fire propagation. In this work, the wood and leaf samples of oil tea, China fir, michelia maudiae, China Gugertree, and masson pine were subject to thermogravimetric experiments in air atmospheres, in order to gain a deep understanding over the three kinetic schemes, i.e. consecutive, parallel and separate schemes. It is found that the three kinetic schemes all lead to mass fractions and kinetic parameters which correlate reasonably well with the decomposition processes, and the two conversion processes intersect within a quite narrow temperature range. Theoretical analysis indicates that with separate features in decomposition processes, the three kinetic schemes may be compatible in kinetic sense, and thus the consecutive and parallel schemes can be simplified by the separate kinetic scheme with high accuracy and reliability. It is also implied that the remarkable differences in the kinetic models and parameters in literatures may be due to the different materials and experimental techniques or conditions used.