Hot Blast Flow Measurement in Blast Furnace in Straight Pipe

This article shows an innovative method to model and validate the hot air flow through the blast furnacés tuyeres. This study will be the basis for flow measurements implementation and safety interlocks for the pulverized coal injection. The flow measurements were taken in the blast furnace down leg pipes by installing refractory Venturi tubes. The system for the calculation of differential pressure takes into consideration the dimension of the Venturi, the air density and compressibility. The objective is to specify the flow transmitters required to automate a control system and implement safety interlocks for the coal injection plant.

Numerical Simulation of Fluid Flow in Blast Furnace Hearth

The liquid flow in blast furnace hearth can result in the erosion of hearth. To prolong the campaign life of blast furnace, the effects of coke bed structure, coke porosity and deepness of taphole on liquid flow in hearth were studied by re model under different conditions. The results show that with the decrease of coke porosity, the peripheral flow is enhanced. Moreover, the existence of narrow coke free zone and the deepness reduction of taphole can increase the flowability on the bottom of hearth.

Resistance characteristics of the ball packed-bed regenerator of the new-type swirl flow hot blast stove

A renovation project of miniaturization and high efficiency is provided for the hot blast stove .The experimental data tested feasibility of the new-type swirl flow hot blast stove. The normal and hot state experiments have been done through changing the angle of gas entering into the regenerator. Factors influencing pressure drop have been studied and analyzed. The experimental results can be formulated in the form of the Ergun equation. The regression equation is obtained. And two modified coefficients are offered to the regenerator pressure drop of the new-type swirl flow hot blast stove.

A mathematical model capable of describing the liquid flow mainly in a blast furnace

The molten liquid flow inside a packed bed is a familiar momentum transportation phenomenon in a blast furnace. With regard to the reported mathematical models describing the liquid flow within a packed bed, there are some obstacles for their application in engineering design, or some limitations in the model itself. To overcome these problems, the forces from the packed bed to the liquid flow were divided into appropriate body and surface forces on the basis of three assumptions. Consequently, a new mathematical model was built to present the liquid flow inside the coke bed in a blast furnace. The mathematical model can predict the distribution of liquid flowrate and the liquid flowing range inside the packed bed at any time. The predicted results of this model accord well with the experimental data. The model will be applied considerably better in the simulation on the ironmaking process compared with the existent models.

SIMULATION OF GAS AND LIQUID TWO-PHASE FLOW THROUGH THE BLAST FURNACE DROPPING ZONE

A three-dimensional mathematical model,based on differential balances of mass and momentum,hasbeen developed to describe the two-phase flow of gas and liquid through the dropping zone of the blast fur-nace.Agreement between observed and calculated values verifies the validity of this model.On the basis of this model,various parameters for the surrounding of the dry zone of Blast FurnaceNo.I-BF of the Beijing Iron and Steel Company have been computed,from which a diagram for demar-cation of fluidization of coke and flooding of slag has been proposed.

Cooling Water Flow Rate Calculation for Hearth of Large Blast Furnaces

The cooling water flow rate for hearth of large blast furnaces was calculated by simulation. The results show that the cooling water flow rate shall be above 4 200m3/ h for hearth of large blast furnaces; to meet requirements of the increasing smelting intensity and to ensure the safety at the end of the first campaign,the designed maximum cooling water flow rate should be 5 900m3/ h; according to the flow distribution stability and the calculated resistance loss,hearth cooling stave pipes with the specification of 76 mm × 6 mm shall be adopted to assure the flow velocity in pipes of hearth cooling stave in the range of 1. 9- 2. 3 m / s.

Numerical modeling of multiphase flow,heat transfer and titanium flow behavior in blast furnace hearth

Understanding the complex phenomena in BF hearth is essential to increase furnace productivity and to extend furnace campaign.We have developed several continuum-based mathematical/numerical models to simulate the multi-phase flow,heat transfer and chemical reactions in the BF hearth.These models have generated an improved insight on the mechanisms for liquid drainage efficiency,lining erosion and wall protection in BF hearth under operational conditions.The current paper gives an overview of these studies in three aspects:Gas flow and pressure on the liquid surface,and their effect on the drainage characteristics;The flow and temperature distributions of liquid iron in BF hearth,and the temperature distribution in the refractories;Finally,titanium behaviors due to titania injection to form Ti(C,N) -rich scaffold on the hearth surface,to protect the hearth from erosion.

“Redistribution” Effect of Lumpy Zone for Gas Flow in BF

The gas flow from tuyere to raceway zone by blasting involves three distributional zones, such as dripping, cohesive, and lumpy zone. The gas flow distribution in lumpy zone directly affects the gas utilization ration and smooth operation in the blast furnace. However, the furnace closeness brings about great difficulty in the study of high-temperature gas flow. The charging and blasting system affecting the gas flow and whether the top gas flow distribution could reflect its inner condition as well as the furnace state, such as hanging or scaffolding, which have become the main problems for the research on gas flow. Recently, several researches overseas studied gas flow distribution using the numerical simulation method; however, such a research was rare amongst the natives. In this study, the flow model of gas in cohesive and lumpy zone was established using the numerical simulation software and the gas flow distributions with uniform distribution of burden permeability, scaffolding of wall, and nonuniform charge level were analyzed. As a result, the effects of cohesive zone and lower parts on the gas flow are very limited and the charge level largely affects the distribution of top gas flow. Therefore, it was found that the distribution of top gas flow could hardly reflect the inner gas flow. The process is called ＂redistribution＂ effect, which means that the gas flow after passing through the raceway, dripping, and cohesive zone is distributed when it flows into the lumpy zone.

Study on the stability control technology of large-scaled blast furnaces

Nowadays,there are two major trends,which are the increasing blast furnace （BF） working volume and the decreasing fuel resource as well as the decline in its quality,in the ironmaking filed. The two trends lead to the difficulty in the BF operation. The decline of the BF stability requires higher and more elaborate operational techniques. A reasonable and compatible BF comprehensive operating system,as the base of the BF stabilization,is desired to satisfy the demand of large-scaled BF developments. Based on the practical operation of Baosteel No. 3 BF in 2010, the present work analyzes and discusses the basic rules of large-scaled BF stable control techniques,and further optimizes and improves its gas flow control techniques, develops strategies against the decline in fuel quality, which will contribute to the promotion of largescaled BF operational techniques progress.

Liquid Jet Blasting Using Ultra-High Frequency Supersonic Pulsed Air Jet

This paper reports an experimental study on a liquid injector assembly integrated with an ultra-high frequency pulsed air jet that operates at 21 kHz. The active air-blasting assembly steadily injects a liquid through four micro-nozzles of 0.4 mm diameters each, positioned around a 1 mm nozzle through which the pulsed actuation jet flows out at supersonic velocity. High-frequency compressible air vortexes and shock waves generated by the injector atomize the liquid stream into finer droplets and distribute them to a larger area to improve mixing with the ambiance. The paper presents the design details and preliminary studies on the flow field characteristics of this novel injection scheme, which is a potential candidate for high-speed flow mixing and control applications.

Characteristics of BF Burden-flow at Material Gate of Bell-less Top

The influence of material gate position in bur- den-flow rate has been studied by simulating exper- iments.A mathematical model describing the char- acteristics of burden-flow at the material gate of bell-less top blast furnace(BF)is established in this paper,in an attempt to solve the problems in bur- den distribution,especially to eliminate the over- lapping or disconnection of the burden at the be- ginning and at the end of a ring,which plays a quite important role in the blast furnace operation.

Numerical Simulation of the Flow of a Molten Blast Furnace Slag in an Open Channel

Despite its industrial importance, the flow of molten blast furnace slag in open channels has not been sufficiently studied. In this work, the unsteady non-uniform flow of a molten blast furnace slag in a rectangular open channel is numerically studied by solving the Saint-Venant equations by means of an explicit backwards finite difference scheme. An Arrhenius-type dependence of the viscosity of the slag on temperature is assumed. To calculate that viscosity, four temperatures are considered, namely 1450˚C, 1500˚C, 1550˚C and 1600˚C. To study the dynamic response of the system, a half-sinusoidal pulse with duration of 5 s is imposed at the channel entrance. According to the numerical simulations, for all the temperatures considered, the slag flow in the channel for an angle of 5 degrees is supercritical in nature. However, for an angle of 1 degree, the flow is transcritical, that is, it presents a transition from subcritical to supercritical.

不同类型线性切割索爆炸切割有机玻璃的损伤特性分析

为了探究不同类型线性切割索切割有机玻璃(PMMA)的损伤特性,通过数值模拟的方式对微爆索、楔形聚能切割索、圆弧聚能切割索3种类型切割索爆炸切割PMMA板过程中的应力分布和损伤特性进行了分析。结果表明:切割索的切割损伤为复合损伤,表面有射流或爆破形成的切割槽或破碎槽,背面有严重的反射应力波拉伸层裂损伤。微爆索切割PMMA的冲击破碎区深度为2.6 mm,宽度为2.4 mm。楔形聚能切割索形成的裂缝断裂深度为3.8 mm,最大宽度为4.0 mm。圆弧聚能切割索侵彻深度为3.2 mm,宽度为3.0 mm。楔形聚能切割索的切割效果最佳,其次是圆弧聚能切割索,最后是微爆索。

大型高炉回旋区内气-固流动行为研究

以国内某3200 m^(3)高炉鼓风参数为依据,采用计算流体力学-离散单元法(CFD-DEM)耦合的方法,模拟研究了高炉回旋区动态演化过程,分析了焦炭颗粒接触特性及流化状态。结果表明,初始鼓风阶段回旋区高度的增量大于深度的增量,持续鼓风,回旋区尺寸逐渐稳定,焦炭颗粒的低配位数增多,高配位数减少,回旋区边缘焦炭颗粒趋于流态化;同一速度下,随着风口面积增大,回旋区内气体与焦炭颗粒之间的曳力增大,焦炭颗粒接触力减弱,接触概率降低,加剧回旋区内焦炭颗粒流态化程度。

安钢3号高炉炉况失常分析

通过对炉况波动时各工艺参数的变化和原燃料使用情况进行分析研究,得出炉况波动的原因:入炉含铁原料品种多,并且持续采取优化煤气利用的措施,导致高炉气流分布发生变化,中心及边沿气流均明显减弱。压量关系变得紧张后,产生局部气流,最终引起炉况失常。通过改善料柱透气性,疏导两股气流,减少入炉含铁原料种类等措施,高炉炉况迅速恢复。

唐钢2号高炉长稳高效生产实践

长周期稳定顺行是高炉炼铁追求的目标,唐钢2号高炉开炉达产后,通过采取优化炉料结构、提高原燃料质量、优化高炉操作制度、强化管理等手段,高炉日产在8800 t/d以上,利用系数3.0 t/m^(3),实现了高炉的长稳高效生产。

飞机尾喷流对舰面温度场影响仿真分析

本文针对舰载飞机舰面起飞过程中,尾喷流冲击偏流板形成的回流温度场和偏流板板后的温升情况开展了仿真计算和参数影响规律研究。首先,设计了一个双发大推力的舰载机模型,并通过与台架试验结果对比,验证了采用k-ε湍流模型的计算流体力学方法对喷流速度场和回流速度场模拟的准确性。然后,通过控制变量方法研究了喷管轴线角度、喷管间距、喷管扩张比对进气道出口温度畸变强度和偏流板后温度场的影响规律,发现适当增加喷管轴线上翘角度或增加喷管间距可以有效抑制进气道吸入高温回流、降低板后舰面温度场极值,当双发喷管间距增加到3倍喷管喉道直径时,进气道出口温升几乎为0。最后,从偏流板的改进设计出发,在不增加舰面额外设备的前提下,研究了偏流板表面横向开槽对偏流板引射能力的影响,结果表明偏流板表面横向开槽可以增强尾喷流的周向引射能力,有效降低回流温度场的强度。

高原露天台阶上部冻层破断规律数值分析

上部冻层是影响高原露天台阶爆破效果的主要因素之一,为明确高原露天台阶上部冻层在爆破荷载作用下的破断规律,利用颗粒流数值方法模拟了天然单冻层和人工复合双冻层分别在单、双排炮孔作用下的破断过程,分析了冻层破断过程的速度、冲击压力和破断后的块度特征。结果表明:冻层在爆破荷载作用下经历了产生裂隙-局部隆起-宏观断裂的破坏过程,对于人工复合冻层,由于上部增加了碎石土层,冻层厚度增大,削弱了冻层整体的隆起趋势,导致破碎块度增大。双排炮孔之间冻层受到的冲击压力率先达到峰值,但靠近自由面的冻层受到的冲击压力峰值更高。单、双冻层在爆破荷载作用下的破断问题可简化为冲击压力作用下的结构断裂问题。双冻层台阶爆破大块率比单冻层大块率高4%~6%,建议在高原露天矿山爆破中,优先通过冻土层厚度确定需要进行特殊处理的区域,并通过调整延期时间达到降低大块率,提高铲转挖运效率的目的。

新钢10号高炉降料面处理炉墙结厚实践

新钢10号高炉因烧结矿质量波动较大、炉况稳定性差及管道频繁发生等原因,出现炉墙结厚。首次采用降料面的方法处理炉墙结厚,降料面过程中炉况稳定,恢复上料后24h内炉况恢复正常。认为在降料面的过程中应密切关注煤气中H_(2)、O_(2)含量的变化,确保含H,量≤12%;随着料面的下降,炉墙结厚物逐步显露之后,结厚物下部受到高温煤气流冲刷作用,上部受到炉顶雾化水冷却作用,结厚物产生裂缝塌的过程中,温度的变化是关键。10号高炉炉墙结厚处理后,主要技术经济指标明显改善,日产量上升155Vd,煤气利用率上升1.1个百分点,燃料比下降10kg/t。

沙钢2号高炉低成本下提产降耗措施

为应对沙钢2号高炉国内澳洲煤资源短缺和非主流矿比例提升,提出了“强化高炉骨架、稳定高炉渣系、优化高炉气流”的整体思路。强化高炉骨架主要是基于实验室40kg小焦炉试验结果,使用国产一类优质焦煤替代澳煤进行优化配煤结构,确保焦炭M4o及CSR达标率的稳定;稳定高炉渣系主要是开发烧结配料精度系统,稳定烧结矿碱度,摸索出适合2号高炉生产实际的镁铝比四段式控制标准,优化炉渣黏度;优化高炉气流主要是针对下部送风制度提高风量和缩小风口面积后,上部调整及时布料矩阵,确保煤气流分布合理。沙钢2号高炉生产实践表明,上述整体思路可行,在低成本情况下实现了提产降耗。