Effect of Indian Medium Coking Coal on Coke Quality in Non-recovery Stamp Charged Coke Oven

The maximum possibility of utilizing the Indian coking coals and inferior grade coking coal for producing metallurgical coke through non-recovery stamp charging technology was investigated. Indian indigenous coals contained low percent of vitrinite (<50%) and higher content of ash (>15%) compared to imported coking coal. Therefore, the selection of appropriate proportion of different types of coals was a major challenge for coke makers. Coal blend selection criterion based on a single coefficient, named as composite coking potential (CCP), was developed. The use of increased proportion of semi-soft coal (crucible swelling number of 2.5) and high ash (>= 15%) indigenous coal in the range of 20%-35% and 20%-65% respectively in the blends resulted in good quality of coke. Plant data of a non-recovery coke oven were used for developing and validating the model. The results showed that the coke strength after reaction (CSR) varied in the range of 63.7%-67.7% and the M-40 value was between 81.8 and 89.3 in both the cases.