Evaluation of the Characteristics of As-received and Washed Low Grade Indian Coals for Their Industrial Applications

Coal is the most widely used source of global energy. With the fast depletion of coal quality in India, utilizing the abundantly available low grade coals through appropriate technologies for meeting the energy demands is the need of time. During the various industrial application of coal, its characteristics are crucial. Five as-received low grade coals from Rajapur, Rajrappa, Kargali, Kedla, and Kathara coal mines of Jharkhand (India) and corresponding washed coals/clean fractions were characterized. These are low moisture-low volatile-low sulphur non-coking coals, except Rajapur coal, which is medium volatile poor coking. Rajapur and Rajrappa coals have medium ash, whereas other coals have high ash. Rajapur coal has the highest C and calorific value followed by Rajrappa, Kedla, Kargali, and Kathara coals; the variation of H and N content is insignificant. After washing, Rajrappa and Kargali are poor coking and Rajapur, Kedla, and Kathara are medium coking. For power generation, as-received coals of Rajrappa and Kedla, and washed coals of Kargali and Kathara can be used; for directly reduced iron purpose, Rajrappa as-received coal can be used. For coke making, washed coals of Rajapur and Kathara coals and stamp charging; Kedla and Rajrappa washed coal with the blend of low ash medium volatile coal and good coking coal, respectively, in conjunction with stamp charging, may be significant. Also, Kargali and Rajrappa washed coals can be used to make formed coke. The rejects from coal washing comprising a substantial amount of coaly matter together with higher ash can be used for power generation using fluidized bed combustion.