Influence of high proportion bituminous coal injection on blast furnace smelting parameters and its control measures
The iron and steel industry is facing the problem of depletion of high-quality coal carbon resources and green carbon reduction,combined with the uneven distribution of coal resources in China,the large proportion of bituminous coal reserves and the global"carbon peak,carbon neutral"development background.The injection of high proportion bituminous coal can make full use of resources,alleviate the smelting cost of enterprises,and reduce the carbon emission of blast furnace smelting,which will become the mainstream trend in the future.In order to investigate the effect of high proportion bituminous coal injection on the process of blast furnace,a mathematical model of high proportion bituminous coal injection in blast furnace was established based on the production data of large blast furnace and the material balance and heat balance.Through theoretical calculation,the variation law of theoretical combustion temperature,gas content,direct reduction degree,carbon and heat distribution and carbon dioxide emission in blast furnace with the increase of bituminous coal injection ratio was analyzed.The results show that when the proportion of bituminous coal is increased by 10 percent point,the theoretical combustion temperature decreases by about 6-7℃,the direct reduction degree decreases by about 0.012,and the gas content in the furnace bosh increases by about 5 m3.Regional carbon,including the total carbon per ton of iron into the furnace,the carbon consumption of direct reduction of iron,the carbon consumption of desulfurization,and the carbon consumption of burning before the tuyere,all show a decreasing trend.The effect of heat distribution in the furnace is obvious.In terms of heat income,the heat release of carbon combustion decreases,the heat release of C and H elements increases,the physical heat brought by hot air decreases,and the overall heat income shows a downward trend.In terms of heat expenditure,desulfurization heat consumption decreases,coal decomposition heat increases,iron oxide decomposition heat consumption is basically unchanged,total heat expenditure is basically unchanged,and the whole furnace heat loss shows a downward trend with the increase of bituminous coal proportion.At the same time,the theoretical combustion temperature and heat loss decrease caused by the increase of bituminous coal ratio by 10 percent point,and the oxygen enrichment rate of 0.3 percent point and the coal ratio of 2.1 kg need to be increased at the same time to maintain the normal condition of the blast furnace.After blast furnace injection of high proportion bituminous coal,the carbon dioxide emission shows a decreasing trend,and the reduction of ton iron is about 3-5 m3.
high proportion bituminous coal injectiontheoretical combustion temperaturedirect reduction degreefurnace gas contentregional carbonheat distributioncarbon reduction
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