Studies on the characterization of Indian coals using FE-SEM and EDS and its relevance to coal washability

摘要

Clean coal technology is a very important area of research and development as it has enormous potential to reduce harmful emissions, improves fuel efficiency which meets the present and future energy requirements. Indian coals are known for drift origin, the associated mineral matter is responsible for formation of ash in the coal, which are intimately mixed with coaly matter during the time of formation. The mineral matter present in the coal has detrimental impact on different end uses. Gradual increase in ash percentage and deterioration of good quality Indian coals have attracted the researchers to look inside the coal for its judicious utilization. Coal is extremely complex and the most heterogeneous fuel, composed of a number of distinct organic entities called macerals and inorganic entities called minerals. The term, "mineral matter", usually applies to all inorganic, non-carbonaceous material, includes those inorganic elements which may occur in organic combination. The inorganic mineral matter divided into two groups-inherent which is grown with plant life and seldom exceeds 2-3 per cent of whole mass while extraneous mineral matters generally consists of large bits and pieces of inorganic material typical of the surrounding geology. These extraneous mineral matters so finely divided and uniformly dispersed within the coal and enter into the coal matrices and behave like inherent mineral matter which cannot be removed by any means of physical washing. The coal at below -500 micron is density separated using centrifuge and studied with FE-SEM and EDS. Knowledge of the morphological relationship between the inorganic phases and organic matter is helpful to devise suitable schemes for cleaning coals containing such particles. The surface morphology, presence of pore and their sizes were carried out using scanning electron microscopy; while EDS analysis helps to determine the elemental composition of the mass of a particular area, advantage is simplicity with accuracy and speed.