Model of Blast Furnace Hearth Drainage

The hearth plays an important role in the operation of the ironmaking blast furnace (BF). A simplified simulation model of the hearth based on the general principles of liquid drainage has been extended to make the model more practical and comprehensive. The tap rates of the liquids are determined by production and taphole conditions, including taphole diameter and length, and the tap‐end conditions are iteratively calculated to yield a quasi‐stationary tap cycle. The model, which considers both a sitting and a (partially) floating dead man, is illustrated with the use of a set of examples, where the effect of variables on the drainage behavior is studied. The model is finally validated by applying it to short‐term data from an industrial BF.     

Heat Transfer Modelling of a Blast Furnace Hearth

This paper describes the development of a heat transfer model with the purpose of studying the heat flows in the hearth of an operating blast furnace. Temperature profiles were calculated for a period of time to study the transition from steady blast furnace operation to an unsteady period, and back to a steady period. This total time period had the highest lining temperatures registered since the beginning of the current campaign. It was concluded that no part of the lining had an inner temperature higher than the critical temperature of 1150 °C. Thus, no refractory could have been in direct contact with slag or iron. The corner between the wall and the bottom was identified to be the most sensitive part of the lining. It is suggested that thermocouples are installed in this area, to improve the temperature control.     

长寿高炉炉缸和炉底温度场数学模型及数值模拟

高炉炉缸和炉底的寿命是影响高炉长寿的关键因素之一。实现高炉炉缸、炉底与高炉寿命同步的措施之一就是在高炉炉缸和炉底冻结一层渣铁壳。要想冻结渣铁壳,在高炉设计时应将1150℃等温线推离炉缸和炉底热面,这就需要计算高炉炉缸和炉底的温度场。为此讨论了目前应用于高炉炉缸和炉底温度场的一些数学模型,并在此基础上开发了通用的炉缸、炉底温度场计算软件。     

高炉炉缸炉底侵蚀判断模型

基于对炉缸炉底衬砖破损机理的分析,采用有限元法建立了炉缸炉底侵蚀判断数学模型。该模型用于推定炉缸炉底的1150℃等温线(侵蚀参考线),并结合知识库中的操作知识对护炉操作进行指导,以维护合理的操作炉型.     

太钢新建4350 m~3高炉长寿炉缸炉底研究

以太钢新建4 350m3高炉为例,论述了为实现高炉炉缸炉底的长寿,从高炉的设计、选材和砌筑等方面采取的一系列措施。炉缸设计采用"传热法",炉底设计采用"隔热法",炉缸炉底整体设计采用了"扬冷避热梯度布砖法"。炉缸选材使用优质高导热系数的碳砖,为了克服冷却壁与碳砖之间捣打料带来较大热阻,砌筑过程中碳砖采用顶砌冷却壁方式,并且严格控制砖衬宽度;炉壳与冷却壁采用分段灌浆。通过建立炉缸炉底传热数学模型,进一步表明了该高炉炉缸炉底优良的性能,投产后1 150℃等温线位于炉缸砖衬热面附近,有利于渣铁壳的形成;同时碳砖内部温度普遍低于750℃,温度梯度较小,碳砖脆化及热应力对砖衬的破坏作用较轻,为日后实现长寿炉缸炉底创造了必要的条件。     

Critical Heat Flux of Blast Furnace Hearth in China

The critical heat flux surveys of thirteen Chinese blast furnaces were carried out.The mathematical model of hearth bottom was established and the temperature field was simulated by utilizing the method of inverse problem based on the collected parameters and temperature data.The critical heat flux and dangerous critical heat flux of hearth were defined and analyzed as well as the initial and investigative critical heat flux of hearth,and the influences of thermal conductivity and residual thickness of carbon bricks on critical heat flux were discussed.The relationships between critical heat flux of stave and hearth bricks were also compared.It is found that the dangerous critical heat flux of these blast furnaces ranged from 9.38 to 57kW/m2.Therefore,there was no uniform critical heat flux of hearth due to the structure design,refractory materials selection,construction quality of hearth and other factors.The heat flux should be lower than the critical heat flux with corresponding thickness of carbon bricks to control the erosion of hearth.The critical heat flux of stave would be much lower than that of hearth bricks with the air gap.However,the critical heat flux of stave should be higher than that of hearth bricks when gas existed between furnace shell and staves.     

Numerical Prediction of Iron Flow and Bottom Erosion in the Blast Furnace Hearth

The blast furnace (BF) campaign life, which is limited by the hearth erosion, will be decisive for the process to maintain its dominance in ore‐based iron production, so timely prediction of the hearth erosion and proper measures to protect the hearth are important issues. The erosion at the hearth bottom has not received much attention, even though the region is believed to be the most vulnerable part of the hearth. A computational fluid dynamic (CFD) model has been developed to deepen the understanding of iron flow and refractory erosion at the bottom of the hearth. Key boundary and internal conditions, such as slag–iron interface and dead man state, are provided by a BF drainage model which reproduces the tapping process. Simulations with the CFD model illustrate how different factors affect the flow pattern, hearth erosion profile, and bottom breakage ratio. It is shown that the dead man state plays an important role for the flow behavior and erosion conditions in the hearth. The model is demonstrated to predict two erosion types that are commonly encountered in practice.     

延长高炉炉缸寿命的技术措施

介绍了3种典型炉缸结构的特点及在我国高炉的应用效果;对合理死铁层深度进行了分析,并介绍了近年世界上新建的部分高炉的死铁层深度及死铁层深度与炉缸直径之比。介绍了目前已获得应用的炉缸状态监测技术,以及实践证明较好的炉缸缝隙压浆和护炉新技术。指出强化冶炼情况下,炉缸死铁层深度应至少为炉缸直径的20%;炉缸出现缝隙时,用重油压浆比用碳糊效果好;如能开发出含钛化物的炭砖,既能起到较好护炉作用,又不会像添加含钛矿那样会造成焦比升高。     

高炉炉缸内衬的温度场设计及其状态与寿命研究

根据高炉炉缸在实际生产中的情况,将炉缸内衬划分为有限单元,采用能量平衡原理建立炉缸内衬温度分布模型,并应用于高炉炉缸内衬设计,进而对炉缸的工艺设计做必要的调整优化,以此获得合理的炉缸内衬温度分布。在此基础上,通过实际生产中的内衬温度推测炉缸内衬侵蚀程度,对炉缸内衬的寿命进行预测。研究结果表明:采用了温度场分布设计技术优化的碳砖-陶瓷杯炉缸内衬的高炉,陶瓷杯侵蚀速率很缓慢,推测蒜头状部位的陶瓷杯使用时间可达10 a以上。     

提高10号高炉利用系数生产实践

根据自身结构特点和技术装备优势,对10号高炉风量、富氧率、顶压等操作参数进行了优化,使利用系数由2.542 t/m3.d提高到2.600 t/m3.d,创造了良好的经济效益。     

Numerical Simulation of Fluid Flow in Blast Furnace Hearth

SymbolList C———Coefficient,1inthepackedbedand0inother place; C1,C2,Cμ,σκ,σε———Empiricalconstant; d———Diameterofcokeparticle; H———Heightofpackedbed,m; P———Pressure,Pa; ui,uj———Velocityalongdirectioni,jrespectively,m·s-1; vA———Vel     

济钢1750m~3高炉炉缸侵蚀情况分析

通过对生产条件及炉缸结构相同的济钢1#、3#1 750 m3高炉炉缸侵蚀情况进行调查,发现1#高炉炉缸呈浅锅底—象脚状侵蚀,扒炉实测表明,炉缸、炉底交接处侵蚀最为严重,炭砖残存厚度最薄处仅为300 mm;3#高炉铁口附近炭砖出现不同程度裂纹,侵蚀严重处炭砖残存厚度600 mm。建议考虑炭砖的微孔度,使用高可靠性热电偶,降低炉底冷却水流量,增加炉缸冷却水流量等,以提高高炉寿命。     

CFD Modeling and Analysis of The Flow,Heat Transfer and Mass Transfer in a Blast Furnace Hearth

Understanding the complex phenomena in the BF hearth is essential to increasing furnace productivity and to extending furnace campaign. Numerical modeling provides a cost‐effective tool to obtain such knowledge. We have developed several continuum‐based mathematical/numerical models to simulate the flow, heat transfer and mass transfer in the lower part of BF and in the hearth. These models have generated an improved insight into the mechanisms for liquid drainage efficiency, lining erosion and wall protection in BF hearth under operational conditions. The current paper provides an overview of these studies, as well as dealing with three specific aspects: (a) Gas flow and pressure on the liquid surface, and its effect on the drainage characteristics; (b) Flow and temperature distributions of liquid iron in the hearth, and the temperature distribution in the refractories; and (c), Titania injection to form Ti(C,N)‐rich scaffolds on the hearth refractory surface, to protect the hearth from erosion.     

包钢4#高炉炉缸破损调查研究

包钢4~#高炉整个炉役寿命长达18年,在国内大中型高炉长寿技术实践中处于领先水平。通过对包钢4~#高炉炉缸和炉底侵蚀状态调查和取样分析发现,象脚状侵蚀部位分布在炉缸炉底交界处,并重点分析了炉缸炉底的侵蚀原因。     

提高大型高炉炉缸寿命的探讨

结合宝钢高炉生产实践,重点探讨了大型高炉炉缸长寿的措施.以传热分析为基础,探讨了炉缸耐材的侵蚀机理及影响因素,认为炉缸耐材及冷却系统的合理选择是提高炉缸寿命的关键,并提出了高炉大型化后减缓炉缸侵蚀的措施.     

莱钢3200m~3高炉炉缸活跃性问题初探

莱钢3200m3高炉受综合入炉品位下降和焦炭反应后强度低等因素影响,炉缸经常出现不活跃的状态,表现为风压升高、炉身冷却壁温度波动和燃料比增加等,改善措施包括调整热制度、装料制度及送风制度,优化出铁模式等。为做好预知预控,初步建立了以高炉物理热指数和炉缸工作出铁指数为依据的炉缸活跃性评价机制。大高炉在原燃料质量下降的情况下,保证好铁水温度及中心温度不下降可避免造成炉况更大波动。     

高炉炉缸炉底侵蚀模型的研究与开发

采用边界元方法建立某一大型高炉炉缸炉底的侵蚀推测二维模型,能够推定高炉炉缸炉底侵蚀线的位置和形状,及时了解炉衬侵蚀状态。从计算所得的侵蚀图来看,侵蚀轮廓是比较合理的,与实际侵蚀情况非常相近。     

高炉炉缸炉底内衬的等效冷却条件计算方法

建立了高炉炉缸炉底冷却的二维有限元传热模型.该模型能计算紊流水冷冷却器以等效对流换热系数表征的冷却参数,能反解服役炉缸实际冷却强度.等效冷却条件参数可用于缩小多维炉缸传热模型的计算域和规模,且不失边界条件精度.文中设计了参数化有限元建模及分析的计算程序,基于管内紊流水努赛尔特征数,定义一个物性综合系数,构造了更为简明的对流换热系数计算表达式.     

炉缸煤气流分布的影响因素

 高炉大型化是炼铁发展的趋势,随着高炉炉缸直径的不断变大,中心不活跃区域越来越大,如何引导煤气到达炉缸中心已成为炼铁工作者关注的焦点。为了解决上述难题,通过建立炉缸煤气流动三维模型,应用CFX数值模拟软件计算煤气流速,分别研究了炉缸直径、焦炭粒径、空隙度以及鼓风动能对炉缸煤气流分布的影响。结果表明：即使炉缸内焦炭粒径及空隙度分布均匀,边缘煤气流速依然大于中心煤气流速,并且炉缸直径越大,中心煤气流越弱。炉缸内焦炭粒径和空隙度分布影响煤气流分布,提高炉缸中心焦炭粒径和空隙度有利于引导煤气到达炉缸中心。同时,为了保障高炉稳定顺行,鼓风参数必须和炉缸透气性协调一致,不能过于依靠提高鼓风动能吹透中心。