Metallurgical properties evolution of coke oven gas zero reforming reduction pellet
The zero reforming of coke oven gas and direct reduced process is of great significance for the green trans-formation of steel enterprises,with significant energy-saving and emission reduction effects.Due to the high compo-sition of φ(H2)/φ(CO)and a certain amount of CH4 in the reduction gas of this process,the reduction atmosphere conditions of this process were simulated,and the effects of different conditions on the metallurgical properties indica-tors such as reducibility,compressive strength,reduction swelling index,and whole ball index during the reduction process of pellets were explored.This is of great significance for the smooth operation and energy conservation of this process.The results indicate that,as the reaction temperature increases,the reduction degree,carbon content,and swelling index increase,while the compressive strength and whole ball index decrease.After the reduction tem-perature increased from 850℃ to 950℃,the increase in carbon content leads to severe expansion and fragmentation of the pellets in the later stage of the reduction reaction,and the reduction degree corresponding to the maximum swelling index changes from 40％-50％to about 60％.After replacing CO with an equal amount of H2,in the early stage of the reaction,due to the increase in reduction rate,the swelling index gradually increases,while the compres-sive strength and whole ball index decrease.In the later stage of the reaction,due to the inhibitory effect of H2 on the growth of iron whiskers and carbon deposition,the swelling index of the pellets decreases,while the compressive strength and the whole ball index increases.By using equal amounts of N2 to replace CH4,the reduction degree,car-bon content,and swelling index of the pellets decrease,while the compressive strength and whole ball index increase.After the reduction degree of the pellets exceeds 40％,the range of changes in various metallurgical proper-ties with the change of φ(CH4)gradually increases.When the reduction time of pellets under various conditions is 20-40 min and the reduction degree is 60％-80％,the corresponding changes in metallurgical properties reach their extreme values.During the production process,attention should be paid to the indicators of pellets in this area.The carbon evolution process of CH4 has a certain deteriorating effect on the metallurgical properties of pellets,and φ(CH4)in the vertical furnace should be controlled.
zero reforming of coke oven gas-hydrogen based vertical furnace processpelletsmetallurgical prop-ertygas componentscarbon precipitation
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