OXYGEN-ENRICHED COMBUSTION MECHANISM OF LIGNITE

In this work, thermogravimetric experiments were carried out in a thermogravimetric analyzer under O-2/N-2 atmosphere with an oxygen content ranging from 21 vol. % to 70 vol. %. Malek method combined with iso-conversional method and non-isothermal method was employed to determine the burning dynamical function of lignite in high temperature burning region with different oxygen concentrations. The results indicated that the lignite has different burning dynamical function in different oxygen conditions. The combustion mechanism function of lignite belonged to 3-D model when the oxygen concentration is below 30%. The combustion mechanism of lignite belongs to a random successive nucleation growth model when the oxygen concentration is between 40% and 50%. Kinetic burning model of lignite in high burning temperature region with different oxygen concentrations was established. The kinetic parameters were obtained from the kinetic burning model of lignite using Kissinger-Akah-Sunose method.