Petrographic properties with respect to VM content of coal

Abstract

Petrographic analysis of coal is most critical step that must be taken into consideration regarding pulverized coal combustion. Petrographic constituents of coal play an important role and petrographic constituents have different combustion activeness. VM (volatile matter) content changes with respect to the coal rank. Petrographic composition of coal is also is a function of coal rank. That is why, coal fired power plants not only take proximate analysis of coal on board but also they should conceive the petrographic analysis. In this study, 3 coal samples with different VM content respectively are analyzed in terms of proximate and petrographic analysis. Petrographic analysis resulted as lowest VM content (20.98 %) of coal has the lowest vitrinite percentage (20.8 %). VM content are close for the analyzed two coals (20.98%, 23.38%) and vitrinite composition are close (21% and 32 %) for them. Not only petrographic composition is evaluated but also the reflection measurement of these 3 coals is obtained. In terms of reflection measurement of these coals, two coals with lower VM has the biggest range (0.40-0.94) and the coal with highest VM content has the narrowest range of vitrinite reflection (0.50-0.79) respectively. In addition, microscopic observations are carried out and pictures are provided in the order of better understanding the effect of petrographic composition on combustion.