Investigation of the effects of coal mineral matter content on the burning process

High capacity coal-fired power plants use lignite coals which can not be utilized in other industries due to its high amounts of mineral matter content and low calorific value. It is very important to determine the chemical composition and mineral matter content of the coal sample for its mining, preparation and consumption. Mineral matter content of the coal is not just a component to be carried to the place to be fired and discarded after burning because the originated fly ash causes some serious problems in burning systems. The chemical composition and fusion behavior of the coal ash should be known in addition to mineral matter content of the used coal to overcome these problems.In the first phase of this study, the determination of the physical, chemical and mineralogical composition of the coal, coal ash and slag samples from some coal-fired power plants (Soma, Yatağan, Yeniköy and Kemerköy) which are reported to be having slagging problems in their boiler units have been done. The determination of the fusion temperatures of ash and coal samples from coal-fired power plants have been done in the second phase of the study, slagging tendencies of the samples have been revealed using the calculated empirical values according to the chemical compositions. Some additives were used to modify chemical composition of the coal ash and the changes in the slagging tendency have been observed in the third phase of the study.The results of the studies showed that it is possible to reduce the slagging by using a coal mixture produced by blending a coal sample with another coal sample having high acidic oxide ratio.Key Words: Flying ash, fusion temperature, mineral matter, slagging