The Research On The Countermeasure And Variety Of Mass Coal Injection To The Blast Furnace

PCI is the key technology of reducing coke rate and cost for the blast furnace. And it is the effective way to adjust the furnace condition. For one thing, the coal resource is abundant and the price is cheaper than metallurgical coke; for another, it can reduce the RAFT and create the opportunity of enriched blast and high temperature blast, and it will strengthen the smelting operation. Moreover, PCI can be an available way to accommodate heat system.To insure the blast furnace operate favorably in a mass of coal injection, the flow of four phase involved coke in the bottom of BF, liquid slag and iron, gas, UPC should be maintain normally. The research and the practice indicated that mass of coal injection could bring flooding because of the increase of gas and primary slag viscosity and the decrease of material bed's void fraction. The performance of soft coal and anthracite coal is different, and it will affect the furnace condition. So we should analyze the change of operation parameters and make suggestions.The thesis can divided into two parts: first, theoretically, build the coal injection model of blast furnace which can analyze the change of operation parameters in the condition of large coal injection and enriched blast. The model has been debugged and emendated by using the actual data of No.6 BF at Lianyuan Steel Co., and it can be used in spite of dissimilar condition of operational provisions and materials, work out the correct index and present the determination of operational provisions, predict the economic index and pig iron cost, find out the rules of BF energy using and the replacement ratio under different coal injection structure, help people make reasonable operation system and achieve high output , low consume under high coal rate. Second, practically, make dissimilar charge composition according to the actual charging of Wuhan Iron and Steel Corp, and then analyze the droplet performance by using the droplet furnace, test viscosity and melting point of primary slag in different combustion rate. After that, we can determine the right charge composition of the best droplet performance and flow performance so as to optimize the slagging process, minimize the bad effect of mass coal injection, accelerate the BF operation.