Different mechanisms of coke microtexture formation during coking coal carbonization

摘要: Abstract Textural and microtextural evolution of five coking coals during carbonization were observed by optical microscopy (OM) transmission electron (TEM) to determine the mechanism(s) coke microtexture formation. Ultrathin sections, obtained ultramicrotomy, from chars quenched at numerous close temperatures in plastic stage, examined TEM 002 dark field mode. By coupling Gieseler plastometry results, these observations led two different mechanisms for For MacClure coal which, present case, is one passing through best developed a mechanism similar pitch was observed. Although they did not show Brooks Taylor mesophase structure, very small spherules up 1.5 μm size found occur, growing number size, finally coalescing give domains. These composed practically parallel polyaromatic structural units (PSU). In case Norwich Park coal, with highest rank least domains completely process due improvement, solid state, pre-existing preferential planar orientation PSU.