Ore-coke mixed charging is a potential technique for optimizing the charging pattern. Recently, the charging of small-sized coke（ nut coke） with the ferrous burden layer has been applied to reduce raw material usage...Ore-coke mixed charging is a potential technique for optimizing the charging pattern. Recently, the charging of small-sized coke（ nut coke） with the ferrous burden layer has been applied to reduce raw material usage and decrease costs. Various studies indicate that mixing nut coke with ferrous burden can enhance the reduction kinetics,improve the softening and melting properties, and have a positive effect on the permeability. Although mixed charging, especially the addition of nut coke to the burden layer, has been used in the industry for various reasons ,the mechanisms and side effects for using nut coke are not well understood, and the mixing ratio remains limited in actual blast furnace operation. High-temperature experimental studies were conducted to increase the understanding of the complex process of reduction, softening and melting properties, and permeability in a blast furnace when mixing nut coke with an ore layer. The effect of the nut coke mixing ratio and nut coke size was investigated under various reducing conditions. To describe the reduction processes of burden materials, numerous experiments were interrupted at different stages of the reduction, and the collected materials were examined by using image analysis. The reduction degree of mixed charging（iron ore mixing with nut coke） was improved when using nut coke at the temperatures of 800 ℃ and above. The reaction rate of ore-nut coke mixed charging was higher than that of standard charging without the use of nut coke.展开更多
The charging pattern may affect blast furnace permeability, coke ratio, and the freedom to select lowgrade raw materials. Ore-coke mixed charging is a potential technique for optimizing the charging pattern. In recent...The charging pattern may affect blast furnace permeability, coke ratio, and the freedom to select lowgrade raw materials. Ore-coke mixed charging is a potential technique for optimizing the charging pattern. In recent years,charging small-sized coke （nut coke） into the burden layer has been applied to save raw materials and decrease cost. Although mixed charging, especially adding nut coke into the burden layer, may have many advantages, the mechanisms and side effects of nut coke use are not well understood, and the mixing ratio is still limited in industrial blast furnace operation. In this study ,the status of mixed charging, especially nut coke used in blast furnaces, was investigated. A cold flow model was established to study the permeability of the packed bed in the blast furnace ＂dry zone＂ under different conditions with the aim of better understanding the mechanisms of mixing coke and nut coke into the burden layer. The effect of coke size, mixing coke ratio, layer numbers, and gas flow rate on the pressure drop of the packed bed was investigated. The experimental results show that mixing the nut coke in the ore layers decreases the pressure drop to different extents depending on mixing ratio.展开更多
文摘Ore-coke mixed charging is a potential technique for optimizing the charging pattern. Recently, the charging of small-sized coke（ nut coke） with the ferrous burden layer has been applied to reduce raw material usage and decrease costs. Various studies indicate that mixing nut coke with ferrous burden can enhance the reduction kinetics,improve the softening and melting properties, and have a positive effect on the permeability. Although mixed charging, especially the addition of nut coke to the burden layer, has been used in the industry for various reasons ,the mechanisms and side effects for using nut coke are not well understood, and the mixing ratio remains limited in actual blast furnace operation. High-temperature experimental studies were conducted to increase the understanding of the complex process of reduction, softening and melting properties, and permeability in a blast furnace when mixing nut coke with an ore layer. The effect of the nut coke mixing ratio and nut coke size was investigated under various reducing conditions. To describe the reduction processes of burden materials, numerous experiments were interrupted at different stages of the reduction, and the collected materials were examined by using image analysis. The reduction degree of mixed charging（iron ore mixing with nut coke） was improved when using nut coke at the temperatures of 800 ℃ and above. The reaction rate of ore-nut coke mixed charging was higher than that of standard charging without the use of nut coke.
基金carried out at Delft University of Technology with the financial support of M2i(Materials Innovation Institute)under the project number M41.5.09326
文摘The charging pattern may affect blast furnace permeability, coke ratio, and the freedom to select lowgrade raw materials. Ore-coke mixed charging is a potential technique for optimizing the charging pattern. In recent years,charging small-sized coke （nut coke） into the burden layer has been applied to save raw materials and decrease cost. Although mixed charging, especially adding nut coke into the burden layer, may have many advantages, the mechanisms and side effects of nut coke use are not well understood, and the mixing ratio is still limited in industrial blast furnace operation. In this study ,the status of mixed charging, especially nut coke used in blast furnaces, was investigated. A cold flow model was established to study the permeability of the packed bed in the blast furnace ＂dry zone＂ under different conditions with the aim of better understanding the mechanisms of mixing coke and nut coke into the burden layer. The effect of coke size, mixing coke ratio, layer numbers, and gas flow rate on the pressure drop of the packed bed was investigated. The experimental results show that mixing the nut coke in the ore layers decreases the pressure drop to different extents depending on mixing ratio.
