Abstract: A thermogravimetric experiment was performed to investigate the mass loss of wheat straw in inertial ambience of nitrogen. The results show that, in the process of mass loss, there exist three stages: preheat drying, pyrolysis and thermal decomposition of inorganic components, accompanying mild carbonization in the third stage. At the same time, the characteristic parameters, such as onset temperature, final temperature and peak temperature, increase along with the increase of heating rate. Furthermore, the dual extrapolation method was utilized to obtain appropriate kinetic mechanisms to model the pyrolysis of wheat straw. It was concluded that the mechanisms of pyrolysis for wheat straw follow second-order reaction. In addition, the parameters of chemical kinetics, such as activation energy and frequency factor, were obtained as well. The preliminary comparisons between the model and the experimental data validate the reliability of the kinetic mechanisms as a whole. Finally, the causes of the discrepancy were analyzed.

Key words: biomass, pyrolysis, thermo-gravimetric analyse, dual extrapolation method