Research On Burden Flow Trajectory And Burden Surface Shape Of Bell-less Top Blast Furnace

The distribution system is an important means to adjust the condition of the blast furnace,and it plays an important role in the output,fuel ratio,and anterograde of the blast furnace.The research on the burden distribution of the bell-less top blast furnace not only has the overall study of the burden flow trajectory and drop point distribution,but also the study of the burden surface profile and the particle size distribution formed by different burden distribution modes from the particle scale.On this basis,this paper used SOLIDWORKS and EDEM's Geometry to establish the geometric models for the charging system of a 1280m~3 string-tank bell-less top blast furnace in a factory,and numerical simulations were conducted with DEM physical properties of charging materials.The flow trajectory of the burden particles during the distribution process and the shape law of the material surface formed are studied and the visual simulation of the burden flow trajectory and surface profile shape is realized.The specific research content and results are as follows:(1)Calculate and analyze the influence of parameters such as the inclination angle of the chute(12°-41°),the type of burden(coke and ore),the depth of the feed line(0-2m)and the structure of the chute(Semicircle,rectangle,with or without liner)on the distribution flow trajectory.The results show that:(1)The radius of the landing position increases with the increase of the inclination angle of the chute.When the inclination angle is 13.3°,the charge does not contact the chute during the falling process.(2)Under the same inclination angle,the width of the material flow after the coke leaves the chute is smaller than that of the ore,the particles are more aggregated,and the coke landing point radius is 0.1m larger than that of the ore.(3)As the depth of the stock line increases,the radius of the coke and ore landing position continue to increase,and the difference between the two is also increasing;At the 1.4m feed line,the coke landing position touches the inner wall of the furnace,while at the 1.6m feed line,the ore will touches the furnace wall.(4)The average drop radius of coke after passing through the semicircular and rectangular smooth chute are 2.68m and 2.38m,while the average drop radius of the coke after passing through the semicircular and rectangular chute with liner are 2.44m and 2.31m,So when using rectangular lined chute to cloth coke,the landing position radius is the smallest.(2)Calculate and analyze the effects of the two distribution modes of"center coke charging"and"platform adding funnel"on the burden surface profile,the distribution of particle size in the longitudinal and radial regions,and the distribution of the quality ratio of ore and coke,and compare the difference between the two burden distribution modes through the method of multiple batches of burden.The results show that:(1)When using 2 batches of"center coke charging"cloth,in the radial direction,the average particle size of coke particles from the center to the edge changes to"increasing,then decreasing and then stable".The average particle size of coke particles in the middle zone 4 is the largest(40.97mm),50mm and 70mm particle size particles account for a relatively high proportion,43.2%and 22.2%respectively.In the radial direction,the average particle size of the ore does not change much,and the distribution is relatively uniform.(2)When using 2 batches of"platform adding funnel"cloth,in the radial direction,the average particle size of coke particles from the center to the edge changes to"first decrease and then stable".The average particle size of coke in zone 1 is the largest(44.88mm),50mm and 70mm The proportion of coke particles in particle size can reach45.5%and 37%respectively,and the range of change in the area 2-10 is not large;while the ore particle size distribution is relatively uniform.In the longitudinal direction,the average particle size of the two charge materials gradually increases.In the longitudinal zone 4,the average particle size of coke takes the maximum value(44.77mm).The proportion of coke particles with a particle size of 50mm and 70mm can reach 42.8%and 38.4%respectively.(3)After placing 8 batches of materials in the model,we found that:adopting the"platform adding funnel"distribution mode,the amount of coke in the center area is less,and the ore layer in the edge area is relatively flat,thereby ensuring the reasonable development of airflow in the center and edge areas.