Losses of combustible substance on the background of characteristics of fly ashes of the selected polish coal-fired power plants

Abstract

ABSTRACT The subject of the article is the quantitative–qualitative characterization of unburned carbon in fly ash, occured in power plants in southern Poland, fired with hard coal. Significant differences were found in the chemical and mineralogical composition of ashes, divided in groups regarding the combustion technology, i.e. pulverized boilers and combustion boilers with the fluidized bed. In the grain analysis of the ash samples, an increase in yield of the separated grain classes along with the reduction of grain size was found. The tendency was confirmed that the content of unburned carbon increases along with the increase in grain size. In the analyses of the chemical composition of grains it was found that the thicker coal grains are significantly contaminated with mineral inclusions, which was not observed for the grains smaller than 20 μm in size.