(p186) Examination of coke formation through microstructure of sole-heated oven tests

摘要

We have performed micro-CT imaging, using the Imaging and Medical Beamline of the Australian Synchrotron, ofsamples from sole heated oven (SHO) experiments. To create the samples, a SHO was modified for rapidquenching and removal of a vertical core. The SHO was loaded with a 50mm bed of crushed coal, having a sizedistribution similar to that of coke oven feed. The bed was heated from below at 20oC/min up to 300oC then10oC/min until the base of the sample reached 600oC or 625oC, then rapidly quenched, in order to preserve theinternal structure of the sample. The 3D images of the samples provide remarkable insight into the coke formationprocess. They show regions consisting of individual, untransformed coal; single bubbles growing within(presumably) softened coal particles, expanded volumes consisting of large numbers of coalesced voids and resolidifiedsemi coke, some including vertical fissures. Using 3D image analysis we delineate the different regionsof carbonization: untransformed coal, initial softening, maximum expansion and resolidification. We also exploreproperties of the void structures within the sample, such as pore connectivity and pore size distribution. Theapproach provides a promising means for improving our understanding of the formation of coke microstructure.