Research On Development Of Coal Injection Efficiency For Guofeng Blast Furnace

Pulverized coal injection is an important measure to reduce the coke consumption and the cost of hot metal production;it has been the major trend of ironmaking technology.The implementation of coal injection into BF(blast furnace)is a systematic and complex project,which requires the long-term stability of BF operation and good economic results.The blast furnace of Guofeng plant started to inject pulverized coal since 2004.There have two separate coal injection systems.Compared to the 1780 m3 BF system,the equipment of the 450 m3 BF system is outdated and the production management is relatively disorderly.In this study,the coal storage,transportation and batching systems of the two systems were optimized and develop,and the practical research on the BF operation adjustment and coal optimization for injection was carried out.The main contents include:(1)In order to improve the storage and transportation of coal,improve the stability of coal blending,new coal storage and coal blending equipment are built and Build and put into use.The stability rate of coal-fired calorific value increased from less than 80%to about 88%.Through improving the management of coal injection workshop,reduce the number of staff by 70 and increase the per capita output of pulverized coal by 2.5 t/d.(2)The milling and blowing system were modificated and developed.The output of milling is increased by 2 t/h,and the unplanned downtime of injection system has been eliminated,which improves the operating rate of the overall equipment.The application of the coal injection pipe filter reduces lance block from seven times a week to two.After the clean and environmental protection device of dispenser was applied,there was no environmental accident caused by cleaning the dispenser.(3)In order to ensure the stable and smooth operation of the blast furnace,the measures such as improving the quality of charging material,the operation with high blast temperature and the high oxygen enrichment rate,increasing the charging weight,are applied to control the reasonable theoretical combustion temperature and the operating furnace type.The blasting condition of the blast furnace is obviously improved,the slips and collapse of the stock column are reduced,and the utilization coefficient of BF and the power generation of the TRT are greatly improved.(4)Based on the long-term experience,a rapid measurement and comprehensive evaluation system is devolped for pulverized coal.The operation mode of injection with anthracite,bituminous coal and extracted coal is gradually formed.The ratio of bituminous coal could be 47%and upgraded coal to 39.38%.In actual application,with the fluctuation of the price of coal,the ratio of each coal is adjusted by calculation to achieve the lowest cost(5)Industrial tests on coal injection additives were carried out.The results show that the comprehensive coke ratio of the 1780 m3 blast furnace in the test phase is reduced by about 2.72 kg/tHM,the carbon content of dust ash decreased by 2.14%,indicating that the proper amount of pulverized coal additive can strengthen the pulverized coal combustion process.Through the implementation of the project,the equipment of the coal injection workshop has been greatly improved;the coal injection effect and the management level have been improved.In the future,Guofeng should select the appropriate coal blending structure and coal injection ratio according to the actual situation of its own blast furnace.When the conditions are appropriate,it can increase the coal injection volume and save costs and create benefits for Guofeng blast furnace ironmaking.