Effect of O2 concentration on combustion behavior and kinetics of coal gangue during oxy-fuel combustion and oxy-steam combustion

In this work, the effect of O-2 concentration on combustion behavior and kinetics of coal gangue during oxy-fuel combustion and oxy-steam combustion were studied by non-isothermal thermogravimetric analysis technology. The results showed that the increase of O-2 concentration could improve the combustion performance of coal gangue. The O-2/CO2 atmosphere was unfavorable to the combustion of coal gangue compared with the O-2/N-2 atmosphere. Furthermore, the gasification reaction could accelerate overall carbon consumption in oxy-steam combustion with 5% O-2 concentration; and the presence of H2O could delay the ignition and accelerate burnout at this condition. Kinetic analysis showed that the combustion of coal gangue in O-2/N-2 and O-2/CO2 atmosphere followed the first-order kinetics under O-2 concentrations studied; and the combustion in O-2/H2O atmosphere followed the 0.5-order kinetics at 5% and 10% O-2 concentration, while it followed the first-order kinetics at 21% O-2 concentration.

Automated summary

This study found that increasing oxygen concentration can improve the combustion performance of coal gangue, while high oxygen content atmosphere is unfavorable for combustion. Gasification reaction accelerates overall carbon consumption, and kinetic analysis shows different combustion laws under different atmospheres and oxygen concentrations.