New Slag–Char Interaction Mode in the Later Stage of High Ash Content Coal Char Gasification

In this work, characteristics of single brown coal char particle gasification at around the ash fusion temperature was investigated. The particle size of gasification residue decreased with the increase of reaction temperature and the ultimate conversion of coal char increased with the reaction temperature. The SEM-EDS analysis was carried out to investigate the microstructure characteristics of gasification residue obtained at different reaction temperatures. And residual carbon in the gasification residue was demonstrated at the reaction temperature of 1220 °C. Residual carbon flotation on slags phenomenon was observed. In addition, new slag–char interaction characteristics of the gasification residue was concluded in the form of an iceberg mode. The results demonstrated that the particle temperature in the gasifier was above the ash flow temperature contributing to the improvement of ultimate carbon conversion of coal char, especially for brown coal with high ash contents.