Number of heat units liberated when a unit mass of the fuel is burned at constant volume in oxygen saturated with water vapour, the original material and final products being at approximately 25 degree Celsius.
GCV is determined in a automatic bomb calorimeter in terms of kilocalorie per kg
Coal Controller Organization (CCO) finalize the grades of mines/seams/siding/loading points based on sampling done by CCO and analysis in reputed academic institution. After finalization of grades CCO informs the Subsidiaries Companies who in turn notify the grades of mines/seams/siding/loading
Coal quality supplied to the consumers are assessed by the third party sampling agencies. Presently CSIR-CIMFR, QCI and IIT-ISM are doing the third party sampling.
Yes, presently supplies under all schemes and FSA are covered under third party sampling
For availing third party sampling consumers have to sign a tripartite agreement with Coal Company and a third party agency of their choice.
Third party agencies analyse ash, moisture and GCV on equilibrated basis.
Probable reasons for variation of declared and analysed GCV is given below:
- Due to drift origin of Indian coal, seams are highly interrbanded with inconsistent thickness of shale and stone bands.
- High percentage of extraneous impurities and uneven distribution of the impurities across the coal mass.
- For determination of GCV approximately 1 gram of coal sample is burnt in bomb calorimeter and this 1 gram coal sample may not capture the real representation of the coal consignment.
When there is a variation in grade, credit note is issued if analysed GCV is less than the declared GCV and if the analysed GCV is higher than the declared GCV then debit note is raised issued by the Coal Company.
For collection, preparation and analysis of coal samples BIS norms and guidelines given by CCO are being followed.
Indian coal due to its drift origin contains high ash in comparison with imported coal which has mostly originated in situ. But Indian coal contains less sulphur percentage than that of imported coal.