Research on the slagging behaviors of Shenhua coal in different combustion atmospheres

Abstract

Global warming has attracted extensive attention due to increasing CO2 emissions. Oxy-fuel combustion has become an important topic in the domain of energy saving and emission reduction due to its high efficiency in CO2 reduction. The slagging characteristics of coal ash under oxy-fuel combustion conditions are the premise for the successful application of this technology. In this study, we relied on a tubular furnace and flat flame-assisted entrained flow reactor to test coal ash under different atmospheres. The slagging trend of Shenhua coal under oxy-fuel combustion, including its melting point, mineral species, particle size, and morphology, was analyzed. A comparative analysis of different ash samples obtained from different experimental platforms was also conducted. Results showed that the oxy-fuel combustion atmosphere exerted a minimal effect on the melting point of Shenhua coal ash. Moreover, a high oxygen concentration corresponded to a relatively high melting point of ash. Ca existed in the form of CaO under air combustion, and a certain amount of undecomposed CaCO3 appeared under oxy-fuel combustion. Given the same oxygen concentration, the average particle size under oxy-fuel combustion was smaller than that under air combustion. Moreover, particle adhesiveness was stronger and particles more easily gathered under oxy-fuel combustion than under air combustion. Particle aggregation was also more obvious under oxy-fuel combustion than under air combustion. Therefore, the slagging trend under oxy-fuel combustion was obviously higher than that under air combustion.