Practice On The Improvement Of Hearth Activity Of No.2 Blast Furnace At SHAGANG

The hearth of blast furnace is the "engine" of blast furnace production.Coke and fuel are burned here,producing a rising reducing gas,which reduces iron ore to metal.Coke combustion produces space,which creates condition for burden descending.The hearth work is very important,once abnormal must bring the serious influence to the production.Whether the hearth is active or not is mainly affected by the filling condition of coke and the fluidity of liquid slag and iron.The filling state of coke determines the permeable channel in hearth.The fluidity of slag and iron affects the smoothness of slag and iron flowing into and out of hearth.However,with the large-scale blast furnace,especially the extra-large-scale blast furnace,it is difficult to control the distribution of raw materials,the furnace body heat load fluctuation is large,dead column is not active,the hearth center is easy to pile up and other technical problems.Since 2017,No.2 blast furnace in SHAGANG Group has been in a dilemma of frequent production fluctuation,low output,low hearth activity,poor blast and heating capacity,and difficult tapping because of various conditions and peripheral fluctuation,which has posed a series of challenges to the blast furnace operators and administrators.In order to solve these problems,based on the adjustment of 5800 m3 blast furnace in SHAGANG Group,the causes of fluctuation of No.2 blast furnace condition are analyzed,and the corresponding adjustment is made on this basis.The main research contents are as follows:(1)The hearth activity index was introduced to evaluate quantitatively,and it was found that the hearth activity was obviously insufficient.Through the practice of furnace condition adjustment and the reaction of blast furnace,the characteristics that the hearth kinetic energy can not drive the continuous production of blast furnace obviously appear.The problem of the hearth of No.2 blast furnace in SHAGANG is determined,which points out the direction for the next adjustment of blast furnace.(2)On the basis of analysis,taking full advantage of hearth activity as a guide,starting from the improvement of raw fuel conditions,and using the monitoring parameters of hearth,the operation policy of furnace temperature[Si]=0.4%-0.6%and physical heat above 1480? is worked out,and strict monitoring is completed,and hearth heat loss is strictly forbidden.Secondly,to get rid of the frequent adjustment of the distribution system,to establish the control center,to fully dredge the adjustment of the edge,to speed up the reduction of the central ore,to use the reduction of the central ore,to speed up the replacement of the central dead coke pile,thus eliminating the occurrence of hearth accumulation and improving the activity of the hearth.Finally,the discharge of slag and iron should be paid attention to,the daily output of blast furnace should be 6500 t/d and the fuel consumption should be 515?520 kg/tHM.(3)The blast furnace hearth of SHAGANG has been maintained by improving the means of taphole,hearth grouting and protecting the hearth with V,Ti-bearing material.After furnace protection by titanium ore,the hearth activity and consumption increased slightly,but hearth temperature decreased obviously,the furnace protection effect is more conducive to the long campaign of blast furnace and sustainable production.A series of adjustment actions are carried out in order to improve the utilization of gas,reduce the consumption,realize the long-term stable and smooth operation of the blast furnace and enhance the index competitiveness through optimizing the distribution matrix,improving the gas passage,improving the quality of the raw materials and washing the blast furnace on the basis of the existing personnel conditions,raw materials and blast furnace equipment.Through theoretical research and practical application in blast furnace operation,the problems of inactive hearth and a small amount of piling-up of No.2 furnace are solved,and the matrix adjustment direction with more guiding significance to actual production is established.At the same time,a series of optimization measures such as air flow control and coal injection ratio control in actual production can be obtained through theoretical calculation.In the practical application,we can draw lessons from the experimental results of this subject,according to different raw material conditions combined with their own characteristics of the furnace,take reasonable and effective measures to effectively restore hearth activity,improve the level of blast furnace production.