Solvent refined coal from high-ash non/weakly coking coals for use in metallurgical coke making. Part Ⅱ: utilization as a coking additive

摘要

Solvent refined coal (SRC) prepared from high-ash Indian non/weakly coking coals, as reported earlier (S.B. Choudhury, B.B. Brahamachari, S.R. Dwivedi, A.K. Roy, P.K. Dasgupta, M. Chakraborty, R. Hague, Solvent refined coal from high-ash non-coking coals/washery middlings for use in metallurgical coke making: part Ⅰ, Fuel Processing Tech., USA, June '96, pp. 203-213), when blended in small doses (8-12%) with substandard coking blends and carbonised, yields coke with increased anisotropy as well as hot and cold strengths. This is reflected by positive improvement in the values of the Micum indices (M_(40) and M_(10)), coke reactivity index (CRI) and the coke strength after reaction with CO_2 (CSR) and also the optical texture of the resultant coke as reported in this paper. The authors confirmed, by pilot scale carbonisation tests (250 kg/batch) that SRC produced by the technology developed (S.B. Choudhury, B.B. Brahamachari, S.R. Dwivedi, A.K. Roy, P.K. Dasgupta, M. Chakraborty, R. Hague, Solvent refined coal from high-ash non-coking coals/washery middlings for use in metallurgical coke making: part Ⅰ, Fuel Processing Tech., USA, June '96, pp. 203-213) can help in substituting high-fluid low ash prime coking coals (PCC) to the extent of 30% (by weight). The use of SRC can thus accommodate additional quantum of medium coking coals (MCC) in the coking blends of the major Indian steel plants. The large reserves of indigenous medium coking coals, especially low volatile medium coking coals (LVMC) after beneficiation can also be used in the blends for making blast furnace grade coke thereby conserving scarce prime coking coals.