Characteristics of solid by-products from entrained flow gasification of Australian coals

Coal mineral matter undergoes a series of transformations during entrained flow gasification before exiting the gasifier as liquid slag, fly ash, or fly slag. As a result of these transformations, there is the potential for the composition of the slag and fly ash to differ significantly from that of the mineral matter in the feed coal. ork presents new data from the testing of four Australian coals in a 5 MWth pilot-scale entrained flow gasifier and describes analyses of the morphology, microstructure, and composition of samples of solid by-products obtained from the pilot-scale test program. The results of these analyses indicate some significant differences in composition between the mineral matter of the feed coal and the solid slag and fly ash by-products, which also impacts on the viscosity behaviour of the slags. These differences are primarily attributable to two factors: the partitioning of the mineral matter between fly ash and slag in the gasifier and, in some instances, the interaction of the fresh slag with slag produced from different coals and/or test runs which was already present on the wall of the gasifier.