Study on the ash fusion characteristics of Zhundong iron-rich coal with different densities under complex atmospheres

Abstract

During the gasification process of Zhundong iron-rich coal, particles with different characteristics are deposited at different positions on the wall. Affected by the chemical composition and the atmosphere, there are significant differences in the fusion characteristics of ash particles at different positions on the wall. The Zhundong iron-rich coal was separated into samples with varying densities, and the ash fusion temperatures for each sample were measured under different atmospheres. The results indicated that as the density of the coal samples increased from less than 1.4 g/cm³ to greater than 1.5 g/cm³, the content of Fe₂O₃ in the coal ash rose from 5.33 % to 33.79 %. Compared with the oxidizing atmosphere, the ash fusion temperatures decreased in the weakly reducing atmosphere, and the decreasing trend becomes more obvious as the density increased. The ash FT of coal greater than 1.5 g/cm³ decreased abruptly from 1304 °C to 1059 °C, while that of coal less than 1.4 g/cm³ decreased only from 1258 °C to 1229 °C. FactSage calculations showed that the liquid phase content in high-temperature ash under oxidizing atmosphere decreased with increasing density. Under reducing atmospheres, the liquid phase content in high-temperature ash of different density fractions decreased with increasing CO content.