Mathematical model of burden distribution for the bell-less top of a blast furnace

Due to the difficulty in measuring the burden trajectory directly in an actual blast furnace （BF）, a mathematical model with Coriolis force and gas drag force considered was developed to predict it. The falling point and width of the burden flow were obtained and analyzed by the model, the velocities of particles at the chute end were compared with and without the existence of Coriolis force, and the effects of chute length and chute torque on the falling point were also discussed. The simulation results are in good agreement with practical measurements with laser beams in a 2500 m3 BF.

Designing for Long Campaign Life Blast Furnace (1)──The Mathematical Model of Temperature Field for Blast Furnace Lining and Cooling Apparatus and New Concept of Long Campaignship Blast Furnace Cooler Design

The physical and mathematical model of temperature field for blast furnace stave coolers was established. The computation results show that the heat resistance of 2-6 mm water scale within the cooling pipe is about 7%-20% of the total heat resistance of cooling stave body, as for drilling duct type, the heat resistance of 2-6 mm water scale is about 88%-98% of the total heat resistance. Using drilling duct or full cast pipe can eliminate gas clearance and coating layer between pipes and cast iron body and reduce the heat resistance of the cooler sharply and improve the coefficient of heat transfer to a great extent. The water velocity within coolers can be kept at the 1evel of 0.5- 1 .5 m/s, the higher water velocity can not decrease the hot surface temperature, but can increase energy consumption for cooling water.

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.

Mathematical Model of Hearth and Bottom Erosion in Blast Furnace

Furnace lining erosion is closely related to the operation stability and safety. The detection technology for hearth lining thickness of blast furnace was introduced.By using the data of thermocouples installed in the bottom of furnace hearth,a mathematical model of erosion was established; the real state of the hearth and bottom erosion was studied; the erosion condition was followed,serving for the furnace longevity.

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.

3D model study of coal/coke combustion in a blast furnace effects of coal properties

A three-dimensional mathematical model of the combustion of pulverized coal and coke has been developed.The model is applied to the blowpipe-tuyere-raceway-coke bed region in an ironmaking blast furnace in one computational domain,which includes two parts:pulverized coal combustion model in the blowpipe-tuyere-raceway cavity and the coal/coke combustion model in the surrounding coke bed.The effects of coal properties are examined comprehensively,in terms of coal burnout and gas species distributions.The results indicate that using a coal of fine particle size or high VM content could improve burnout and would affect the gas composition considerably.The burnout is examined in two ways:compared with burnout along tuyere axis,burnout over the raceway surface is a more sensitive and sensible parameter to describe the amount of unburnt char entering the coke bed.The model is useful for examining the flow-thermo-chemical characteristics of the pulverized coal injection (PCI) process under various conditions in a blast furnace.

Development and Introduction of Monitoring System of Refractory Lining Wear in Blast Furnace Hearth

To diagnose the lining condition of the blast furnace hearth during its campaign, are widely used methods based on the analysis of the temperature characteristics of the refractory lining. Measurement of the temperature characteristics is performed by means of a few hundred thermocouples placed inside the refractory lining. The peculiarity of proposed and used mathematical models is a fully three-dimensional assessment of the refractory lining, presence mechanisms of adaptation to the actual thermal conductivity of refractories and optimization calculations to the work in the on-line mode. The new monitoring systems of the lining wear of the blast furnace hearth are established on 5 blast furnaces of integrated iron-and-steel works of China： No.4 by volume 3,200 m3 of “Jinan Iron ＆ Steel Company” in Jinan （683 thermocouples）, No.2 by volume 1,080 m3 of “Henan Jiyuan Iron ＆ Steel （Group） Company” in Jiyuan （212 thermocouples）, No.4 by volume 2,500 m3 of “Guangxi Liuzhou Iron ＆ Steel （Group） Company” in Liuzhou （383 thermocouples）, No.3 by volume 1,750 m3 of “Jinan Iron ＆ Steel Company” in Jinan （524 thermocouples）; No.1 by volume 1,750 m3 of “Jinan Iron ＆ Steel Company” in Jinan （524 thermocouples）.

Numerical simulation for the lower shaft and the hearth bottom of blast furnace

One of the methods forming the shell is to appropriately design the coolingstaves and hearth without overheating during the campaign life of the furnace. The three-dimensionalsteady mathematical models for calculating the temperature distribution in the coolers andtwo-dimensional unsteady mathematical models with phase-change latent heat for calculating thetemperature distribution of the hearth bottom were established. The calculation results show thatthe formation of the slag-metal protection shell can be achieved by optimizing the design parametersof the coolers. Increasing the heat conductivity of the carbon brick can move the isothermal lineof 1150 deg C upward outside the hearth bottom.

Investigating effect of coke porosity on blast furnace performance based on multi-physical fields

Reducing coke use is an effective measure to reduce carbon emission and energy consumption in the blast furnace(BF)ironmaking.Essentially,BF is a high-temperature moving bed reactor,where complex physical transformations coupled with complicated reactions occur.This makes it challenging to investigate the factors determining BF performance with the conventional method.A multi-physical field coupling mathematical model of BF was thus developed to describe its mass and heat transfer as well as its intrinsic reactions.Then,the proposed model was validated with the production data.Under coupling conditions,influences of dominating reactions on BF performance(temperature distribution,gas distribution,iron formation reaction,and direct reduction degree)were revealed.The results indicated that coke combustion,indirect reduction,and direct reduction of iron ore mainly took place nearby the shaft tuyere,cohesive zone,and dripping zone,respectively.Besides,the rate of coke solution loss reaction was increased with the rising coke porosity in the cohesive zone.Considering the effect of coke porosity on the efficiency and stability of BF,the coke porosity of 0.42 was regarded as a reasonable value.

Mathematical model of burden distribution in bell-less top blast furnace

The burden distribution in the shaft of blast furnace is known to affect the gas distribution,heat transfer,and chemical reactions inside the furnace.However,the internal layer structure of burden in the shaft cannot be directly measured.Hence,a mathematical model for evaluating burden profile and layer structure was established.A sensitivity analysis based on the model was implemented to elucidate the effect of some factors on the burden distribution,including the stockline height and the mass of central coke.The results show that the width of funnel zone widens with the increase in stockline height,and the mass percentage of ore to coke in this zone slightly increases.Besides,the mass of central coke shows a significant influence on the width of coke channel,and 2%of batch mass of coke is recommended to implement central coke charging operation.The model has been indirectly verified by the gas temperature in operating blast furnace and successfully applied to online evaluate burden distribution.

Mathematical Model and Its Hybrid Dynamic Mechanism in Intelligent Control of Ironmaking

A hybrid dynamic model was proposed, which considered both the hydrokinetic and the chaotic properties of the blast furnace ironmaking process; and great emphasis was put on its mechanism. The new model took the high complexity of the blast furnace as well as the effects of main parameters of the model into account, and the predicted results were in very good agreement with actual data.

高炉内料层结构动态追踪的技术开发

炉料径向分布影响着高炉下部所形成软熔带的形状和位置,进而间接决定和控制了高炉燃料比的高低.建立了预测高炉内部料层结构的数学模型,并将其转化为可视化界面的软件,供现场人员在线使用,用于计算不同布料参数下料层结构的详细信息,布料参数包括布料矩阵、料线高度、布料方向、径向下降速度分布,预测结果包括径向矿焦比分布、追踪料层位置、料层厚度变化.计算结果均可为现场布料制度优化提供参考依据.

基于运动轨迹和径向距离的高炉料面堆积形状建模方法

高炉料面形貌是反映煤气流分布和煤气利用率的关键指标,研究高炉料面炉料堆积形状数学建模方法对实现高炉精准布料控制和“双碳”战略在钢铁行业落地具有重要意义.针对高炉多环布料情况下料面堆积形状预测难的问题,本文提出了一种基于炉料运动轨迹和径向移动距离的高炉料面炉料堆积形状建模方法.首先,提出了一种与炉料初始状态和溜槽状态相关的炉料运动轨迹建模方法,获取炉料从节流阀至料面的炉料运动轨迹,并确定炉料在炉喉空区的内轨迹曲线和外轨迹曲线.然后,基于炉料运动轨迹和初始料面形状,以体积守恒原则为约束,提出了一种基于炉料径向移动距离的高炉料面炉料堆积形状数学建模方法,获取炉料在料面的堆积形状.最后,基于某钢铁厂2#高炉的尺寸建立离散单元法(Discrete element method,DEM)仿真模型,模型仿真结果验证了所提方法的准确性和有效性.

高炉炼铁大数据技术的发展现状与思考

因缺少废钢资源,我国钢铁生产将长期采用高炉-转炉长流程工艺,高炉操作至今仍主要依赖于人类专家的经验。从高炉数学模型、炼铁知识获取与应用、过程数据的获取等方面阐述了高炉炼铁大数据技术的发展现状,并提出了推进高炉炼铁大数据技术的思考。认为各种类型的数学模型是工业软件,在炼铁大数据技术中处于核心地位,但需要针对不同高炉的具体条件研究开发;对高炉内衬工作状态、炉缸内渣铁蓄积量、风口回旋区煤气焦炭,以及滴落带渣铁行为等的在线监测需要先进的检测技术;加强高炉下部焦炭降级行为的研究是高炉炼铁大数据技术发展的迫切需要。

高炉渣基沸石分子筛材料的制备及其响应面优化

以高炉渣(BFS)为原料制备高炉渣基沸石分子筛(BFSZ),为实现对BFSZ制备工艺条件的优化,基于单因素试验结果,采用Box-Behnken Design(BBD)响应面法考察晶化时间(A)、晶化温度(B)、初始硅铝物质的量比(C)等因素对BFSZ阳离子交换量(CEC)的影响。结果表明:响应面法建立的回归模型方程具有高度的显著性,可信度和精确度较高,得到制备BFSZ的优化工艺条件:碱熔温度为600℃、液固比为5∶1 mL/g、晶化时间为8.74 h、晶化温度为98.41℃、初始硅铝物质的量比1.18,此时BFSZ的CEC为3.21 meq/g。经验证,BFSZ的CEC实际值与预测值的相对误差约为1.9%,表明该模型能够很好地反映各因素对BFSZ的CEC影响。

基于PID参数优化的高炉加热炉壳温度控制研究

高炉的炉壳是承受极高温度、腐蚀和机械应力的部件,炉壳温度过高或过低都可能导致热应力、脱渣等问题,从而影响高炉的正常运行和寿命。通过有效的炉壳温度控制,可以保护炉壳免受过高温度和腐蚀的侵害,延长高炉的使用寿命,因此提出基于PID参数优化的高炉加热炉壳温度控制方法。利用空气定压比热、加热炉蓄热室通道面积、蓄热体比热容等多个参数确定高炉加热炉能量平衡方程,采用拉氏变换建立高炉加热炉数学模型。以加热炉数学模型为基础,遗传算法通过变异、交叉和复制等操作优化加热炉PID控制器参数。利用参数优化后的PID控制器、功率调整器、FP93导电仪表、加热管以及温度测量仪组成高炉加热炉壳温度控制架构,实现高炉加热炉壳温度控制。实验结果表明,所提方法可准确检测高炉加热炉壳的温度,控制精度以及效率高,高炉加热炉壳温度控制效果好。

高炉冶炼专家系统的开发研究

介绍了武钢1号高炉专家系统的开发条件、系统结构、数学模型和主要的功能;该专家系统是一种专家系统和数学模型相结合的混合型专家系统,数学模型的计算结果是专家系统开发的基础,利用数学模型和专家系统可以较好地控制高炉生产过程的变化。同时介绍了开发研究的主要成果,如高炉布料控制、炉型管理、炉温控制、炉底侵蚀计算等。系统调试和试用结果表明:该系统可以较好地控制高炉过程,实现高炉的稳定顺行。

高炉优化配料数学模型的研究

为了研究实用的高炉优化配料数学模型,利用线性规划原理,以高炉炼铁工艺计算为基础,结合各种含铁炉料的软熔性能和含铁炉料之间的高温反应性等专家知识,开发了一套基于专家知识的高炉优化配料数学模型,并应用生产高炉现场数据对模型进行了验证。结果表明该模型是合理可行的,能够计算得出同时兼顾炉料冶金性能和配料成本的高炉炉料结构。

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。

高炉炉身下部及炉缸、炉底冷却系统的传热学计算

在高炉冷却器及炉缸、炉底热面凝结一层渣铁壳有利于防止炉衬侵蚀,延长高炉寿命。为了达到这一目的,需要设计无过热的铸铁冷却壁、铜冷却壁和板 壁结合冷却器以及无过热的炉缸和炉底。为此建立了高炉炉身下部冷却器及炉缸、炉底温度场的数学模型,应用C++语言在VC++集成环境下开发了高炉炉身下部冷却器及炉缸、炉底温度场计算软件。计算结果表明,通过优化炉身下部冷却器及炉缸、炉底的设计参数,能够确保在冷却器热面及炉缸、炉底热面凝结一层渣铁壳。目前,国内一些大型高炉的设计中已采用该软件。