Structural properties of coking coal and influence of substituting similar coal types on quality of blending coke
Coking coal is the direct raw material for producing metallurgical coke,with the cost of coal blending accounting for over 85%of the total coking expense.As the resources of high-quality scarce coking coal continue to diminish,it becomes crucial to utilize different types of coal resources and introduce more coal types into coking coal blending based on coal quality characteris-tics,which is significant for reducing costs,increasing efficiency,and ensuring continuous stable pro-duction.The molecular structure of coal directly impacts its behavior during coking process,subse-quently affecting coke quality.This study is based on the actual production use of coking coal blends in a cokemaking plant,introducing four groups of similar coals.Coal characteristics was thoroughly analyzed using Raman spectroscopy analysis,13C NMR analysis,Gieseler fluidity test,and fixed bed pyrolysis experiments.40 kg scale coke oven was used to conduct coal blending coking experiments with similar coal substitution in coal blending for coking,exploring the effects of adding different types of coal,such as gas coal,fat coal,coking coal and lean coal,on the coking process and coke quality of blended coal.It thus provides theoretical guidance for cokemaking plants to substitute similar coals based on coal quality characteristics.The results show that for two types of coking coals(JM1 and JM2),the smaller aromatic cluster branches(S.C.)in JM1 might be the main reason for its low flu-idity and narrower plastic temperature range,and the coke quality of JM1 is inferior to that of JM2.After replacing JM1 with JM2,the coke quality improves.The two types of fat coal(FM1 and FM2)exhibit good caking properties,with considerable portions of defect structures in their chemical struc-tures(AGR+VL+VR/AD),which is favorable for the development of plastic body fluidity,with the better caking property of FM2 resulting in higher cold strength of blended coke.The two types of gas coals(QM1 and QM2)have poor caking properties,and the smaller S.C.of QM2 restrictsits fluidity development,resulting in lower fluidity.Among all coal types,lean coal(PM)has the worst caking properties,and the introduction of PM degrades the quality of the coke.
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维普
