Research on changes in the microstructure of coking coal during thermal conversion process
Thoroughly studying the changes in the microstructure of coking coal during thermal conversion is of great significance for revealing the formation process of coke optical structure and optimizing coal blending structure.A sys-tematic study was conducted using coal petrology research methods to investigate the coal quality and lithofacies char-acteristics of three typical coking coals,the optical microstructure characteristics of coke,the influence of vitrinite reflectance distribution on optical microstructure,and the evolution law of coke optical microstructure during thermal conversion.The results indicate that the strength of coke after reaction is positively correlated with the content of coarse mosaic texture,fibrous and leaflet texture.The content range of three types of coking coal's vitrinite reflec-tance is 0.95％-1.35％,with JM-3＞JM-2＞JM-1.The content relationship in the range of＞1.35％is JM-1＞JM-2＞JM-3.It is not accurate to predict the quality of coke solely based on the distribution of vitrinite reflectance range in coal.During the softening and melting stage of the metaplast,isotropic texture,fusinite and frag mental texture are the main components.As the pyrolysis temperature increases,the content of isotropic texture in coal decreases significantly,and active components such as vitrinite gradually react and melt to form mosaic,fibrous,and leaflet texture.The mosaic and fibrous optical structures in coke are mainly formed during the high temperature coke conden-sation reaction stage,during which some active components in the fusinite and frag mental texture continue to undergo transformation to form mosaic texture.
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维普
