Characterisation of coal and chars in fluidised bed gasification

Abstract

There is currently a gap in the understanding of the morphological transformations experienced by high ash and intertinite-rich coals undergoing conversion to char during atmospheric gasification. In this study, work has been carried to characterise residual char generated from some selected high-ash South African coals. The selected coals are different in rank, maceral and mineral matter composition. Pilotscale fluidised bed gasification tests were carried out on the selected coals within a temperature range of 900 to 935oC. Char residual remaining after atmospheric gasification in a pilot plant bubbling fluidised bed reactor were analysed by petrographic techniques, X-ray diffraction, scanning electron microscopy (SEM), EDX, Raman spectroscopy, BET N2 surface and Hg porosity techniques. These techniques revealed key features in the transformation of these coals to char during gasification.