Comprehensive experimental investigations on Co-combustion dynamics and multi-pollutant formation characteristics of coal gangue and biomass in oxy-fuel atmosphere

Abstract

Based on the co-combustion principle of coal gangue and biomass, the combustion characteristics, kinetic mechanisms, and pollutant emission characteristics of mixed coal gangue and wheat straw in oxy-fuel atmosphere were investigated by conducting experiments with a thermogravimetric analyzer and a tube furnace in this paper. The results indicated that the comprehensive combustion characteristics, reaction rate and burnout rate of the samples can be improved with the increase of O2 concentration in oxy-fuel atmosphere. When O2 concentration is 50 %, the emission peaks of pollutants SO2 and NOx are the highest. The increase of biomass content can accelerate the combustion reaction rate, increase the total weight loss rate, enhance the comprehensive combustion characteristics of the samples significantly, and reduce the release of SO2. A faster heating rate corresponds to higher ignition temperature, burnout temperature, and the maximum weight loss rate temperature, leading to the improvement of comprehensive combustion characteristics and flammability. The combustion temperature has a significant effect on pollutant release, and the release of CO and SO2 is relatively low under the condition of 900∼1000 °C. Therefore, the use of oxy-fuel co-combustion technology holds the potential to significantly improve the combustion performance of coal gangue, reduce pollutant emissions, and provide a theoretical guidance for the resource utilization of coal gangue and biomass.