| The blast furnace upsizing is a significant symbol of the metallurgical industry development,and it is motivated by the oxygen-enriched coal spray technology's enhancement.Coke for large-scale blast furnace needs more than higher cold state strength and hot state performance but enough lumpiness.Therefore,metallurgist from all over the world claimed the importance and change rule of blast furnace coke's lumpiness through the study over the blast furnace tuyere coke.And explained the reason why coke lumpiness's sharp cut off in the blast furnace.The in-depth study of coking coal's shrinkage and the lumpiness in the process of coal blending coking plays an important role in the controlling of the coke lumpiness and the stabilization of the blast furnace operation.By studying the relationship between the shrinkage performance of different metamorphic degree coking coal during pyrolysis and their lumpiness and coking performance,this paper further explores the effective methods to improve the lumpiness and strength of coke.This study adopts the typical coking coal to explore the coking performance.The pyrolysis shrinkage coefficient's change regulation with temperature change of YK coal,SYS coal,DSHS coal,QJY coal,ML coal,LH coal,SAJ coal and BBG coal is studied through the research on pyrolysis shrinkage performance of coking coal.The results indicate that:The pyrolysis shrinkage coefficient of coking coal with different metamorphism ranks is differently sensitive to the change of heating rate,while QJY is the most sensitive.When the heating rate increases from 3?/min to 5?/min,?1,max varies from 7.07×10-4?-1 to12.4×10-4?-1.YK has the lowest sensitivity,with?1,max ranged from 8.42×10-4?-1 to8.77×10-4?-1.With the increase of coking coal particle size,the pyrolytic shrinkage coefficient is affected differently by coking coal particle size.Among them,the maximum influence is ML fat coke.When the particle size increases from<0.2 mm to<0.6 mm,the range of?1,max varies from 5.78×10-4?-1 to 13.8×10-4?-1,and the least influence is YK gas coal,whose?1.Max ranged from 8.19×10-4?-1 to 8.63×10-4?-1.In addition,the use of 1 kg of the experimental coke oven to study charging coal fineness of different metamorphic grade coking coal lumpiness and the regulation of the influence of coke performance,the results show that different metamorphic grade coking coal reach the best lumpiness at different charging coal fineness,including QJY coal,ML coke and SAJ coal have the best lumpiness at the 75%fineness,While YK gas coal,DSHS1/3 coking coal and BBG lean coal have the best lumpiness when the fineness of coal is 80%,85%and 85%.The pyrolysis shrinkage coefficients?1,max of coking coal with different metamorphic degrees are well correlated with the average lumpiness of coke,and the correlation coefficients are 0.871 and 0.941.Therefore,the average particle size of coke generated by coking coal can be accurately predicted.When the pyrolysis shrinkage coefficient?1,max of the coking coal is in the range of4.33×10-4?5.06×10-4?-1,the generated coke is of large lumpiness and high strength.Therefore,the relationship between the shrinkage performance of the coking coal and its lumpiness performance is further determined through the coking experiment. |
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