(p459) Determining fusibility of inertinite by comparison of matched coal and coke surfaces using imaging analysis methods

摘要

During coking, for coals of suitable rank, the vitrinite, liptinite and some of the inertinite macerals are fusible and theminerals and remaining inertinite macerals do not fuse. The amount of fusible inertinite in a coal varies betweencoals extracted from differing coal basins/measures and even between coals from similar regions. Inertinitefusibility is related to reflectance, with low reflecting (fusible) inertinite being more reactive than high reflecting(infusible) inertinite. The amount and size of infusible inertinite particles impact on coke quality parameters (i.e.large inertinite, approximately +1.5mm, adversely affects coke quality).The reflectance threshold between fusible and infusible inertinites was investigated for four Australian coals byusing imaging methods on matching coal and coke surfaces obtained from two halves of individual coal lumps,where one half had been coked. The cokes were mapped using Pearson Coal Petrography's recently developedautomated coke characterisation method and the coal halves were mapped using CSIRO' Coal Grain Analysis(CGA) system. It was discovered that the threshold between fusible and infusible inertinite was not a fixed valuebetween lumps of the same coal. However, the reflectance range for the fusible inertinite (from the end of thevitrinite reflectance range to the beginning of the infusible inertinite reflectance range) stayed constant betweenlumps of the same coal. Thus, analysing each lump separately with the same fusible inertinite reflectance range butslightly differing reflectance thresholds enabled all components to be identified correctly.The CGA system was recently upgraded to enhance characterisation of coal particles so that it analysed individualparticles based on their own reflectance fingerprint. The fusible inertinite reflectance range for each coal which wasdetermined by the mapping of coal and coke halves this enabled the inertinite component within each particle to besplit between fusible and infusible inertinite. The system is also now able to determine the size of each fusible andinfusible structure within each particle.