Discussion on key factors affecting fuel rate of blast furnace—Also on appropriate degree of direct reduction
The key factors affecting the fuel rate have long been the subject of debate in the ironmaking community.In fact,both theoretical and practical knowledge of blast furnace operation are required in order to reduce the fuel rate by studying the degree of direct reduction,or the heat consumption per ton of hot metal.This subject has a signifi-cant impact on the basic concepts,technical development directions,and production technical guidelines of the blast furnace.For example,in 2020,some people put forward the production principle of"Blast volume as the key link and hot metal temperature as the basis",which results in a high fuel rate.It raises the question of seeking the key fac-tors to determine the fuel rate in the blast furnace operation.The Rist blast furnace operation diagram and evaluation method of blast furnace production is used for the analysis of the data collected from 22 blast furnaces(＞4 000 m3).The outcome of the analysis shows that the heat consumption per ton of hot metal plays a key role in the fuel rate.This means that the amount of combustibles burned and the oxygen consumed in the tuyere zone play a decisive role,rather than the direct reduction degree.In addition,the method of reduction kinetics and evaluation of blast furnace production efficiency is used to analyze a phenomena that the high gas utilization and shaft efficiency of some blast fur-naces seem cosxisting with the blast volume and adopt excessive center coke charging operation.It is considered that this is against the law of blast furnace operation.The blast furnace should follow the basic principles generally recog-nized by the ironmaking industry which insure the high efficiency of the production,high quality of the hot metal,low consumption,long life and environmental protection.Reducing of the fuel rate is essential,along with efficiza-tion use of the resources,energy,improving of the efficiency of the blast furnace operation and itse the economic efficiency.
direct reduction degreetotal heat requirementoxygen consumptionfuel rateshaft efficiency
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