DIRECT DETERMINATION OF ORGANIC SULPHUR IN COALS USING LOW TEMPERATURE PLASMA ASHER

摘要

Generally two forms of sulphur are present in coals (i) Inorganic (pyrites and sulphates and (ii) Organic (a complex mixture of organo types). The sulphate sulphur is usually present in low amounts except in case of oxidised coals where some of the pyrite has been converted into sulphate. The organic sulphur in coals is intimately bound to the coal molecule. Hence, it is difficult to determine directly in presence of other forms of sulphur. The organic sulphur content in total sulphur of coals may be upto 90%. The total sulphur content of coal will determine whether the present S02 emission standard will be met upon combustion of coal or not. If the content of the total sulphur is too high and the flue gas desulphurization unit is not available, at least part desulphurization, to the extent possible, is a must prior to use of the coal. Physical/ Microbial/Chemical desulphurization processes can remove varying but large amounts of the inorganic forms and only small amounts of organic sulphur. Hence, to avoid any pollution, corrosion, health hazards, wear and tear problems, the content of the latter form should be on the lower side. Therefore, the baseline level of organic sulphur must be known, so that economic and time effective sulphur removal processes can be applied for the purpose.