Effects of silicoaluminate oxide and coal blending on combustion behaviors and kinetics of zhundong coal under oxy-fuel condition

Abstract

Oxy-fuel combustion of high-alkali coal is beneficial for near-zero emission of pollutants in power plants and has the potential for extensive, efficient, and safe utilization of Zhundong coal in future. The present work was performed on oxy-fuel combustion of Zhundong coal, while the effects of silicoaluminate oxide and coal blending on oxy-fuel combustion characteristics and kinetics of high-alkali coal were further studied using thermogravimetric analysis. The thermogravimetric curves of Zhundong coals present two obvious stages but the contrastive coals are different. The increase in oxygen content weakens the impact of coal property on oxy-fuel combustion behavior of high-alkali coal. The addition of Al2O3 and kaolin results in a slight decline of the peak combustion rate, while the influences of SiO2 and diatomite additives are negligible. The additive fraction of silicoaluminate oxide gives rise to a non-monotonic impact on combustion characteristics of Zhundong coal. The interaction effect within blended coal could cause a reduction in reaction rate during the intense combustion stage, while its influence on kinetics is intensified during the later stage of oxy-fuel combustion. The impact extent of silicoaluminate oxide and coal blending on oxy-fuel combustion kinetics of high-alkali coal is highly associated with additive species and individual coals.