| With the rapid development of iron and steel industry,high-quality iron ore and coke are increasingly scarce,and the composition and structure of raw materials and fuels for blast furnace production are complex and changeable,which has a serious impact on the stable operation of blast furnace,the rational distribution of gas flow,the efficient utilization of gas and the production of blast furnace.Taking the characteristics of raw fuel and production conditions of 2500 m3 blast furnace in an iron and steel plant as the object of study,using mathematical simulation and physical simulation methods,combined with the actual production situation and operation system requirements of the blast furnace in the plant,the effects of physical and chemical properties of raw fuel,composition and structure of blast furnace burden,charging system of blast furnace on distribution of blast furnace gas flow,utilization of gas and operation of blast furnace burden were systematically studied.The physical and chemical properties of blast furnace raw materials showed that the size of sinter was relatively uniform,mainly distributed in 5-25 mm,accounting for86.2%of the total sinter,but the content of sinter with particle size less than 5 mm was relatively high,accounting for 4.8%,which was not conducive to improving the permeability of blast furnace charge column;due to the influence of particle size uniformity and moisture content of blast furnace charge,the natural heap angle of coke was larger than that of sinter.The results showed that the content of Al2O3 and MgO in sinter was 2.90%and 2.69%,respectively.Because of their relatively high content,the melting drop and low temperature powdering of sinter were poor.Considering the physical and chemical characteristics of the burden,a material flow trajectory model was established to determine the falling point of the burden.Based on the material flow trajectory model,the stock profile formation model and the burden descent model were established by modifying the charging angle.According to the design parameters and actual raw material conditions of blast furnace,the model was used to simulate and calculate the influence of different charging patterns on the burden profiles.With the decreasing of the coke angle,the coke platform gradually moved to the center of blast furnace,which was beneficial to the development of bordered gas flow.When the coke distribution angle was less than 20degrees,a large number of coke distributes to the throat center,forming a similar effect of central coking,and the central gas flow was overdeveloped.The result of physical simulation showed that during the process of reducing the maximum ore angle of the charging pattern from 40.5 to 33 degrees,the change trend of the burden profiles was basically consistent with the predicted results of the mathematical model.The radial ore-coke ratio decreased gradually in the central region.Considering the distribution of gas velocity,the charging pattern matching the current burden was C339.25?37.25?3 6 2?3 4 2?3 1 2?25.5?O239 2?37.25?3 6 2?34.25?3 2?.According to the calculation results of critical ore batch weight and characteristic number of batch weight,in order to ensure the rational distribution of blast furnace gas flow and the efficient utilization of gas energy,the ore batch weight of blast furnace should be controlled between 46.9 and 50tons,the coke batch weight should be controlled between 9.4 and 10 tons,and the material line depth should be controlled at about 1.2 m.Production practice has proved that after applying this charging system to 2500 m3blast furnace,the utilization ratio of gas increased from 42%to 45%,the number of blast furnace abnormalities decreased from 16 times per month to 8 times per month.,and the operation condition of blast furnaces was improved. |
PDF Full Text Request