Exploring the potential of petrographics in understanding coal pyrolysis

The morphology analysis reveals the differences in reactivity among the coals. It was found that a link existed between total reflectance and aromaticity, total reflectance and fuel ratio, total reflectance and surface area, and total reflectance and percentage of carbon dry ash-free basis (daf), which all gave a definite relationship confirming, that reflectance can be used as a measuring index in coal analysis. The mean total reflectance of the lignite coal for the temperature regime 450°C-700 °C is 1.26-4.36 %; sub-bituminous coal is 1.49-4.64 %; bituminous coal is 1.39-4.86 %; semi-anthracite is 2.15-4.86 %; and anthracite is 2.56-4.79 %. Thus, the large difference in the initial total reflectance between the different coal ranks became very narrow by 700 °C.