Investigation on the combustion kinetics of non-caking coal under various ventilation rates

Abstract

Ventilation provides the oxygen required for coal combustion, but it also accelerates the thermal loss of reaction system. To investigate the influence of ventilation on coal combustion, the characteristic temperatures and stage variation were analyzed. Furthermore, the kinetic mode was determined and the apparent activation energy was calculated. The results indicated that the increase of ventilation rate made the boundary temperatures for different stages decreased. The contribution of thermal decomposition effect to mass loss increased, and the contribution of burning effect correspondingly decreased. The ventilation rate mainly presented an influence on the kinetic mode at the second half of coal burning. The kinetic mode transformed from three-dimensional diffusion to random nucleation and subsequent growth when the ventilation rate reached 200 ml/min. In addition, under the same conversion rate, the apparent activation energy during thermal decomposition first increased and then decreased, and reached the maximum when the ventilation rate was 100 ml/min. The apparent activation energy during coal burning first decreased and then increased, and again decreased, and the increasing trend appeared when the ventilation rate was within 100–150 ml/min. These findings will provide guidance for the control and prevention of coal combustion by adjusting air leakage.

Keywords

• Coal combustion
• Ventilation rate
• Stage characteristics
• Kinetic mode
• Apparent activation energy