Illustrating the effect of physicochemical properties within vitrinite and inertinite on residual carbon formation in drop tube furnace

The high carbon content and poor combustibility of the fine slag produced by the entrained – flow gasification limits its resource utilization. From coal chemistry, residual carbon formation is highly related to the coal macerals. In this study, Meihuajing coal was selected to be separated and enriched macerals by density gradient centrifugation. Different macerals were gasified at 1300 °C and H₂O/O₂ conditions in the drop tube furnace to collect residual carbon. The results showed that the area shrinkage of inertinite grew to 0.90 at the early stage, but final conversion required a longer induction period to realize. The residual carbon of vitrinite had richer pore structure and larger specific surface area as well as lower degree of aromatization and graphitization than inertinite, resulting in higher reactivity. The present study is important in understanding the relationship between the formation of residual carbon and the structure of coal macerals.