Disposition Pattern of Sulphur Functional Groups in High Sulphur Ledo Coals of Assam

Studies for determination of sulphur functional groups present in Ledo coal of Assam State of North Eastern Region of India were carried out using Temperature Programmed Reduction (TPR) method. TPR studies were carried out in presence of Resorcinol and hydrogen gas to arrive at the final result. TPR studies on model sulphur compounds viz. L-Cysteine, synthetic rubber, Thiokol, having hydroxyl terminal groups, thioplast, pyrite with sand, and Garlic were carried out in order to assign various sulphur functional groups present in Ledo coal. Six numbers of hydrogen sulphide evolutions from Ledo coal were observed in the temperature range of 190 – 220C, 260 – 290C, 360 390C, 460 – 490C, 510 – 540 C and 590 – 620C corresponding to mercaptan/ disulphide (0.30), Thiol (1.70), AromaticThioether (0.50), Thiophene (0.90), pyrite + part of complex thiophene (0.60), part of complex thiophene (0.30), The thioketonic sulphur in Ledo coal is estimated to be 1.59 using controlled nitric acid oxidation experiments.