CLEANING POTENTIALITIES OF SOME THERMAL COALS OF ODISHA ON ITS BURNING BEHAVIOR

Out of the total Indian coal reserves, the non-coking coals of Odisha constitute about 23%. The coals are spread in two major coal fields namely: Talcher and Ib Valley. The coals contain high ash wherein the extraneous material was intimately mixed in the coal matrix during the formation stage, causing a high level of impurities in the Run-of-Mine (ROM) material. These coals possess difficult to very difficult washability characteristics. Beneficiation of high-ash non-coking coals of India has become the prerequisite for improving the overall economics and efficiency of power generation. To meet the stipulations laid by environmental gazette notification of the Government of India, the non-coking coals are to be beneficiated before they are fed to thermal power stations. Keeping this in view detailed washability studies were carried out on three major coal sources of Odisha and based on the data clean coal at three different ash levels were generated. Combustion studies of the raw and clean coal have been conducted in a Drop Tube Furnace basically to observe the change in the burning behavior with the level of cleaning. From the combustion behavior of the washed fraction, it was found that, for two coal samples, Burnout Efficiency (BE) has improved compared to that of the raw coal, while for another sample, it was observed that at 34 % clean coal ash level the BE has reduced compared to that of raw coal. The studies concluded that for the coals of Odisha, it is better to fix the level of washing a particular coal based on combustion properties of the clean coal rather than taking an arbitrary value