Assessment of the Yield of Products from Coal Carbonization

Correlation factors have been developed for the yield of different products, e.g., coke, tar, liquor, ammonia, and gas obtained from laboratory Gray-King Assay, pilot oven tests and from commercial coke Plants. The yield of gas from commercial oven is higher and the yield of coke lower, evidently due to higher carbonizing temperature which results in cracking. The correlation between assay and experimental oven yield is found to be poor and indicates the need of carrying out larger number of tests on the same types of coals. Addition of 4-5% of coke breeze to coking coals or their blends gives increased yield of coke, tar and gas per ton of coal charged. Blends of high volatile weakly coking coals from Raniganj with 15-20% of low volatile coking coals from Jharia filed or L.T.C. char give metallurgical coke ; the yield of coke is lower but the tar yield is more than double that normally obtained from Jharia coking coals