高炉内不同还原度炉料对软熔带透气性的影响
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摘要
高炉内软熔带区域的透气性是影响高炉稳定顺行的重要因素,并由炉料的软化融化特性决定.当炉料内部发生软化融化时,炉料内对气体的粘性阻力系数及内部惯性阻力系数发生巨大变化,从而导致透气性变差,内部最大压差增大.本研究旨在通过预还原实验及软化融化实验,探明混合料的还原度对软熔带的透气性影响.结果表明:在不同软融阶段,同一还原度混合料层的最大压差明显不同,当料层温度进入融化区时,粘性阻力系数突增导致压差突然上升.由于惯性阻力系数的变化,压差曲线在达到融化温度之后还会继续发生波动.还原度较低时会出现二次压差峰值,随着还原度增加,二次峰值现象减弱.当还原度达到90%时,二次峰值消失,最大压差曲线在融化开始温度后逐步下降.试验结果对提高软熔带透气性,保证高炉内部稳定顺行具有重要的指导意义.
The permeability of the cohesive zone in the blast furnace, which is determined by the softening and melting characteristics of the burden structure, is an important factor affecting the stability and smooth running of the blast furnace. When softening and melting occurs inside the burden, the viscous resistance coefficient and inertia resistance coefficient of the gas in the burden structure change dramatically, resulting in poor permeability and increased maximum internal differential pressure. The purpose of this study is to explore the effect of reduction degree of mixture on the permeability of the cohesive zone through pre-reduction and softening-melting experiments. The results show that the maximum differential pressure of the mixture layer with the same reduction degree is obviously different at different softening and melting stages. When the temperature of the mixture layer decrease while that of the melting zone increase, the viscous resistance coefficient will increase suddenly,which leads to a sudden increase of differential pressure. Because of the change of inertial drag coefficient, the differential pressure curve will continue to fluctuate after reaching the melting temperature. When the reduction degree is low, the secondary peak value of differential pressure will appear. With the increase of reduction degree, the phenomenon of secondary peak value will weaken. When the reduction degree reaches 90%, the second peak disappears, and the maximum differential pressure curve decreases gradually after the melting begins. The test results have important significance on improving the permeability of the cohesive zone and ensuring the stable and smooth operation of the blast furnace.
The permeability of the cohesive zone in the blast furnace, which is determined by the softening and melting characteristics of the burden structure, is an important factor affecting the stability and smooth running of the blast furnace. When softening and melting occurs inside the burden, the viscous resistance coefficient and inertia resistance coefficient of the gas in the burden structure change dramatically, resulting in poor permeability and increased maximum internal differential pressure. The purpose of this study is to explore the effect of reduction degree of mixture on the permeability of the cohesive zone through pre-reduction and softening-melting experiments. The results show that the maximum differential pressure of the mixture layer with the same reduction degree is obviously different at different softening and melting stages. When the temperature of the mixture layer decrease while that of the melting zone increase, the viscous resistance coefficient will increase suddenly,which leads to a sudden increase of differential pressure. Because of the change of inertial drag coefficient, the differential pressure curve will continue to fluctuate after reaching the melting temperature. When the reduction degree is low, the secondary peak value of differential pressure will appear. With the increase of reduction degree, the phenomenon of secondary peak value will weaken. When the reduction degree reaches 90%, the second peak disappears, and the maximum differential pressure curve decreases gradually after the melting begins. The test results have important significance on improving the permeability of the cohesive zone and ensuring the stable and smooth operation of the blast furnace.
引文
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[20] SHE X F, WANG J S, LIU J Z, et al. Increasing the mixing rate of metalized pellets in blast furnace based on the high-temperature interactivity of iron bearing materials[J]. ISIJ International,2014,54(12):2728-2736.
[2] O RTH A, ANASTASIJEVIX N. Low CO2emission technologies for iron and steelmaking as well as titania slag production[J]. Minerals Engineering, 2007, 20(9):854-861.
[3]刘文权.低碳炼铁技术研究[J].中国环保产业,2011(1):20-25.
[4]杨天钧,张建良,左海滨.节能减排低碳炼铁实现我国高炉生产的科学发展[C]//2010年全国炼铁生产技术会议暨炼铁学术年会论文集,北京:2010.
[5]刘晖,薛俊.钢铁工业与低碳经济[J].冶金管理,2010(1):12-16.
[6] ZUO G Q, HIRSCH A. The trial of the top gas recycling blast furnace at LKAB's EBF and scale-up[C]//Proceedings of the 4th ULCOS Seminar. Essen:2008.
[7] HOOEY L, WISKTROM J O, SIKSTROM P.高炉炼铁技术的未来-北欧的研发[J].世界钢铁,2011, 11(1):1-5.
[8] DU S W, CHEN W H, JOHN L. Perfor-mance of pulverized coal injection in blowpipe and tuyere at various operational conditions[J].Energy Conversion and Management, 2007,48(7):2069-2076.
[9]吴俊明,周振峰,彭星,等.氧气高炉回旋区内煤粉燃烧行为的三维数值模拟研究[J].有色金属科学与工程,2018,9(4):1-8.
[10] GUO B Y, ROGERS H, MATHIESON G, et al. Threedimensional simulation of flow and combustion for pulverized coal injection[J]. ISIJ International, 2005, 45(9):1272-1281.
[11]张万龙,郑劲,黄正欣,等.COREX熔融气化炉炉缸流场研究[J].有色金属科学与工程,2018,9(1):1-8.
[12] SHEN Y S, GUO B Y, YU A B, et al. Three-dimensional modelling of coal combus-tion in blast furnace[J]. ISIJ International, 2008, 48(6):777-786.
[13] SHEN Y S, GUO B Y, YU A B, et al. A Three-dimensional numerical study of the combustion of coal blends in blast furnace[J]. Fuel, 2009,88(2):255-263.
[14] LIU Z J, ZHANG J L, YANG T J. Low carbon operation of superlarge blast furnaces in China[J]. ISIJ International, 2015, 55(6):1146-1156.
[15] MEIJER K, DENYS M, LASAR J, et al. ULCOS:ultra-low CO2steelmaking[J]. Ironmaking&Steelmaking, 2009, 36(4):249-251.
[16] ZUO G, HIRSCH A. The trial of the top gas recycling blast furnace at LKAB's EBF and scale-up[C]//Revue de Metallurgie, 2009, 106(9):387-392.
[17] DANLOY G, BERTHELEMOT A, Grant M, et al. Modelling of the blast furnace internal state with mogador[C]//Revue de Metallurgie,2009, 106(1):1-8.
[18] TSEITLIN M A, LAUZTKIN S E, STYOPIN G M. A Folw-chart for iron making on the basis of 100%usage of process oxygen and hot reducing gases injection[J]. ISIJ In-ter-national, 1994,34(5):570-573.
[19] CHUNG S H, Ki Hyun KIM and Il SOHN. DRI from recycled iron bearing wastes for lower carbon in the blast furnace[J]. ISIJ Inter-national, 2015, 55(6):1157-1164.
[20] SHE X F, WANG J S, LIU J Z, et al. Increasing the mixing rate of metalized pellets in blast furnace based on the high-temperature interactivity of iron bearing materials[J]. ISIJ International,2014,54(12):2728-2736.