Mechanism of zinc damaging to blast furnace tuyere refractory

The phenomena of tuyere upward-warp have been found at No.6 blast furnace in Kunming Steel Company China after its blow-in, which has made a great impact on the practical production of the furnace. Thus, a number of efforts have been made to elucidate the mechanism of this phenomenon. The results of investigation and tests revealed that the enrichment and expansion of zinc in the tuyere bricks is the main factor leading to the tuyere upward-warp. The eroding behavior of zinc is that the inner structure of the tuyere bricks turns from dense to loose with entering, enriching and expanding of zinc, which forms spot-like→stripe-like→ditch-like→vein-like→tumorlike eroding passage. Additionally, it is found that the sequence of deleterious ele- ments entering the tuyere refractory is K, Na, Zn and Pb, respectively. Finally, the phenomena and process of zinc crystallization and growth in the refractory have been clearly observed and recorded during this investigation.

Preparation and Properties of SiC Assembled Large Block for Blast Furnace Tuyeres

A SiC assembled large block for blast furnace tuyeres was prepared using silicon carbide particles(3-1 and 1-0.088 mm)and fine powder(<0.088 mm),silicon powder(<0.088 mm),industrial carbon black(N990),microsilica,ρ-Al_(2)O_(3) powder,etc.as raw materials.The developed block was compared with a silicon nitride bonded silicon carbide brick,a self-bonded silicon carbide brick and an imported self-bonded silicon carbide block to analyze and evaluate their service performance.The results show that:(1)in the 0-100 mm zone,the SiC large block mainly consists ofβ-SiC and nitrides such as O'-SiAlON,β-SiAlON,α-Si_(3)N_(4),and Si_(2)N_(2)O,the bulk density is 2.68-2.70 g·cm^(-3),the apparent porosity is 14%-15%,and the material structure is uniform;(2)in the 0-100 mm zone,β-SiC nano-whiskers intercalate with nitrides;with the depth increasing,the number of flocculentβ-SiC nano-whiskers increases,while the number of nitrides decreases;when the depth reaches 150 mm or more,the main bonding phases areβ-SiC and mullite;(3)compared with the reference products,the developed SiC large block has a good basic performance,and after alkali corrosion,the mass change rate is-0.1%,which is obviously superior to the imported self-bonded silicon carbide and the homemade silicon nitride bonded silicon carbide materials.

Optimization of Raceway Parameters in Iron Making Blast Furnace for Maximizing the Pulverized Coal Injection (PCI) Rate

This paper presents a method by which the maximum possible rate of pulverized coal injection (PCI) in blast furnace can be predicted. The method is based on a two-step approach. First, a first principle simulation model of the blast furnace is used to generate data sets for the development of a linear model of pulverized coal injection rate. The data has been generated randomly in MATLAB software within the range of operating parameters (constraints) of the blast furnace. After that, the coefficients of the function have been determined. The inputs and the resulting outputs formed the data on which the linear optimization model was developed. Next, the linear model was used for maximizing the pulverized coal rate injection by optimizing the other variables. Two operating Indian Blast Furnaces have been chosen to validate the optimization model.

Numerical simulation of the effect of coaxial and cross-axis injection modes on pulverized coal combustion in the raceway of blast furnace tuyere

The aim of this study is to investigate the influence of the angle of the pulverized coal (PC) injection lance on the combustion characteristics of fuel in the raceway of blast furnace tuyeres. Using FLUENT software, a Euler-Lagrange three-dimensional numerical model was constructed to analyze the influence of different positions of blast furnace tuyere coal powder injection lance (coaxial and cross-axis) on key parameters such as temperature distribution, gas flow, and combustion efficiency. The results demonstrate that adjusting the angle of the injection lance significantly modifies the average and peak temperatures in the raceway, while the composition of gas components remains relatively stable. When the injection lance angle is 10°, the average temperature and peak temperature in the raceway are 2294 K and 2747 K, respectively. When the injection lance angle is 12°, the combustion efficiency of the PC reaches 80.8%. This study reveals the significant impact of the injection lance angle on the combustion process. Especially at an angle of 12°, the combustion efficiency of the blast furnace significantly improves. With coaxial injection, the combustion rate increases as the distance between the injection lance tip and the tuyere increases. This paper is instructive for the optimization of the blast furnace combustion system, which improve fuel utilization efficiency and reduce environmental emissions. This paper provides practical recommendations for adjusting blast furnace operational parameters, offering insights for achieving more efficient and environmentally friendly industrial production.

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.

CFD-DEM study on the synergistic effect of coke consumption and particle dynamics in the blast furnace raceway

In this study,the gas-solid flow process in the blast furnace raceway is numerically simulated using coupled computational fluid dynamics and the discrete element method(CFD-DEM).The coke reaction kinetics data are imported into the DEM model to reproduce the consumption process of each coke particle.The effects of inlet gas velocity and angle on the morphology of the raceway,coke consumption rate,coke bed temperature,and particle size distribution in the blast process are systematically investigated and analyzed.The results show that the consumption of coke particles promotes the formation of raceways during the blast process.At the same time,a coke mixture layer is produced at the edge of the raceway.The higher the inlet gas velocity,the thicker the coke mixture layer in the middle and upper parts of the raceway region,and the larger the proportion of small particles in the coke mixture layer.The effect of the inlet gas angle on the raceway region is less than the inlet gas velocity.However,with the increase in the inlet gas angle,the high-temperature region of the coke bed extends downward gradually,which is conducive to activating the hearth.

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.

Gas-Particle Flow and Combustion Characteristics of Pulverized Coal Injection in Blast Furnace Raceway

The two-dimensional steady-state discrete phase mathematical model is developed to analyze gas-particle flow and combustion characteristics of coal particles, as well as components concentration and temperature distribu- tion of coal gas in the process of pulverized coal injection of blast furnace raceway. The results show that a great deal of coal gas discharges on the top of raceway away from the tuyere, and the residence time of coal particles in the re- gion of blowpipe and tuyere is 20 ms or so and 50 ms when it reaches raceway boundary. The pressure is the highest at the bottom of raceway and the maximal temperature is about 2 423 K. The char combustion is mainly carried out in the raceway and the maximum of char burn-out rate attains 3× 10-4 kg/s.

Interaction mechanism between coal combustion products and coke in raceway of blast furnaces

The interaction mechanism between the combustion products of pulverized coal injected and coke in the raceway of blast furnace was studied through thermodynamic calculation and experiments.The results indicated that additives significantly affected the melting property of coal ash in high temperature zone.Although the unburnt char,raw coal ash,and catalyzed coal ash failed to wet the coke surface,the wettability of the catalyzed coal ash on the coke was greater than that of the raw coal ash.Since the unburnt char had weak reaction with the coke surface,it showed little influence on the surface morphology of the coke.The interaction between the raw coal ash and the coke gave rise to the increase in the pore size on the coke surface.However,the raw coal ash only affected the coke surface and the entrances of the pores owing to its poor fluidity.After being melted,the catalyzed coal ash was expected to immerge into the inside part of the coke and then react with the coke,resulting in an expansion and increase of coke cavities.The raw coal ash and the unburnt char reduced the coke reactivity,while the catalyzed coal ash improved the coke reactivity.Thereinto,the coal ash containing Fe2O3 exhibited a larger influence on the reactivity than that containing CaO.

Cold Model of Coal Gas Component Concentration Distribution in Blast Furnace Raceway

Primary distribution of coal gas in blast furnace raceway has an important effect on blast furnace ironmaking process. The coal gas component concentration distribution was studied experimentally using a three-dimensional cold model. The results showed that CH4 concentration diminishes along with the height increasing on vertical section of raceway, and the concentration is the highest in the bottom of raceway. CH4 concentration increases gradually along.the raceway depth with the lowest concentration value in front of the tuyere. The distribution of CH4 concentration has different characteristics in different raceway zones.

考虑风口回旋区影响的高炉热风分配模拟

以鞍钢新5号高炉为研究对象,对比分析了空喷及考虑风口回旋区这两种工况下高炉热风的周向分配情况.结果表明:当风口参数相同时,空喷与考虑风口回旋区这两种工况下的热风分配规律相同,即在高炉圆周0°,90°,180°和270°方位的风口风量和鼓风动能较大,45°,135°,225°和315°方位的风口风量和鼓风动能较小;空喷和考虑风口回旋区这两种工况下的风量极差分别为3.65 m^(3)/min和7.29 m^(3)/min,标准差分别为1.32和2.71;空喷和考虑风口回旋区这两种工况下的鼓风动能极差分别为9.93 kJ/s和19.90 kJ/s,标准差分别为3.62和7.41;与空喷工况相比,考虑风口回旋区工况下热风和鼓风动能分配的不均匀性更为明显,热风分配结果更准确.

高炉鼓风条件对回旋区形态影响的数值模拟研究

针对高炉回旋区难以实验观测,研发了二维欧拉—颗粒多相流动模型,对高炉回旋区形成进行了数值模拟,研究了鼓风速度、鼓风角度对回旋区尺寸和形状的具体影响。研究结果表明,当鼓风速度从150 m/s增至250 m/s时,回旋区气相体积分数及尺寸显著增加,深度和高度分别从0.75 m和1.24 m扩展至1.4 m和2.36 m。另外,鼓风角度的调整在回旋区的水平和深度方向同样起到了关键作用,当鼓风角度从0°调整至-30°时,回旋区高度保持在2 m左右,深度从1.52 m降至1.13 m,特别是较小鼓风角度有利于增加回旋区深度。研究结果为高炉鼓风操作参数优化提供了科学依据,对于提升高炉运行效率和生产能力具有重要的指导价值。

基于CFD-DEM方法的高炉回旋区气固运动行为及形貌特征研究

本文以某3200m3高炉为对象建立等比例三维局部数学模型,采用CFD-DEM耦合算法分析了风口回旋区形成过程中鼓风空气和焦炭颗粒的运动行为,并研究了鼓风量和风口直径对稳态回旋区形貌特征的影响。结果表明,风口回旋区在形成过程中,高速热风与焦炭颗粒进行剧烈的动量交换,随着鼓风冲击深度的增加,气流末端速度减弱,气流向阻力较小的风口上方发展,回旋区空腔结构初步形成。空腔内部空隙率较高,料层阻力较小,回旋区附近气流趋向于沿回旋区边界流动并发展为涡旋状流场,部分焦炭颗粒在回旋区边界做高速运动。此外,提高风口鼓风量和减小风口直径均会显著增加稳态回旋区在高度和深度方向上的尺寸,空腔的截面形状也由圆形逐渐转变为类似羽毛状的椭圆形。

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。

喷吹神东高钙烟煤对高炉回旋区热状态的影响

高炉风口和回旋区的热状态对炉内煤气流的一次分布具有重要影响,进而影响高炉的经济技术指标。为探究喷吹神东高钙烟煤对高炉回旋区热状态的影响,本文通过收集某钢铁企业试烧期间高炉鼓风参数及其他各项操作参数,采用Fluent仿真模拟方法,建立风口回旋区的三维燃烧模型,系统分析不同喷吹条件下温度分布、气体分布、速度分布的变化规律,从而确定在风口复杂条件下喷吹神东高钙烟煤对高炉回旋区热状态的影响。模拟计算结果表明:神东高钙烟煤和ES无烟煤燃烧后产生的还原气体量最多,生产时有利于矿石的还原;向高炉喷吹神东高钙烟煤、HX烟煤、WN烟煤、SG烟煤与ES无烟煤混合煤粉时,燃尽率分别为72.25%、70.11%、68.87%、67.56%,神东高钙烟煤与ES无烟煤混合喷吹时煤粉的燃尽率最高,这是由于神东高钙烟煤和ES无烟煤的CaO质量分数较高,其在风口、回旋区内的燃烧特性最佳;混合喷吹神东高钙烟煤与ES无烟煤时,风口、回旋区内的煤气成分和煤粉燃尽率等方面要强于其他三种情况,适宜向高炉喷吹。

高炉风口喷吹煤粉的燃烧模拟研究

为了减少高炉炼铁过程的焦比,现代高炉通过风口喷吹煤粉代替部分焦炭。以某高炉的设计参数与生产数据为模拟条件,建立高炉风口回旋区喷吹煤粉燃烧的三维模型,对直吹管、煤粉喷枪、风口、回旋区、焦炭床等高炉下部区域的煤粉燃烧现象进行模拟研究,并结合该高炉提供的生产数据验证模型的可靠性。模拟结果显示,热风离开风口进入回旋区,最大速度达到257m/s,之后不断减小。煤粉进入高炉后,挥发分在回旋区内距离风口截面0.4m处开始析出,在回旋区内距离煤粉喷枪1m处形成2600K的高温区域。部分粒径大于70μm的煤粉在回旋区内未完全燃烧,就进入焦炭床并沿炉缸中心向上运动,燃尽率过低,影响高炉透气性。

基于Workbench的高炉送风装置直吹管有限元分析

文中针对高炉送风装置的直吹管进行了静力学分析和模态分析,研究其结构及振动特性。在静力学分析方面,利用有限元方法建立了直吹管的数值模型,并对其进行分析,以了解筒体的整体变形及等效应力情况。模态分析方面,提取了直吹管前20阶模态的固有频率,并对前6阶的振频、振型和振幅进行了详细分析。研究结果显示,直吹管的固有频率随阶数递增,符合无阻尼振动的特征。此外,前6阶模态的振型和振幅得到了全面解析。通过静力学分析和模态分析,深入了解了高炉送风装置直吹管在静力学和振动方面的特性,为进一步的结构设计和优化提供参考。

酒钢3#、5#高炉炉型变化后生产对比浅析

炼铁厂3#、5#高炉均进行了大修改造,双高炉将炉身角、炉腹角、高径比适当进行了缩小,高炉由“瘦高型”转变为“矮胖型”,其中改造的参数除5#高炉将风口个数由16个减少至14个外,其余参数均相同,但改造后,在后续生产实践中,双高炉表现不同。针对炉型变化后,双高炉的运行状况进行了对比分析。

从风口回旋区模拟谈风口参数对风量的影响

基于鞍钢新5号高炉生产数据,在考虑风口回旋区条件下,探讨了风口回旋区体积、风口直径及风口插入深度对风量的影响。结果表明:风口回旋区体积由0.6769m^(3)增大到0.7186m^(3)时,风量从158.02m^(3)/min增加到163.41m^(3)/min,与空喷相比,风口风量更大;风口直径分别为110mm、115mm、120mm时,风口直径每扩大5mm,风量依次增加了5.81m^(3)/min、12.16m^(3)/min,与空喷相比,随着风口直径的增加,风量增加的趋势更加明显;风口插入深度分别为480500、520、560mm时,风量分别为159.61m^(3)/min、159.64m^(3)/min、159.69m^(3)/min、159.76m^(3)/min,与空喷相比,随着风口插入深度的增加,风量会增大,但增幅较小。

高炉风口回旋区多形貌颗粒混合流动特性数值模拟

【目的】高炉的稳定运行和能耗控制受制于风口回旋区内复杂的物理化学行为,因此对回旋区内混合多形貌颗粒的气固相互作用机制进行研究。【方法】采用计算流体力学-离散单元法耦合方法对高炉风口回旋区内混合多形貌焦炭颗粒的流动行为和动力学特性进行数值模拟;系统地研究和分析4种不同的混合非球形颗粒体积分数对风口回旋区演化形貌和微观结构等的影响。【结果】随着非球形颗粒的体积分数从0增至9%,回旋区的宽度和高度分别增加96%和67%,转动能则增加3.53倍;颗粒所受曳力随非球形颗粒混合体积分数的增大而增大,颗粒间接触法向力概率密度函数分布也会向左偏移且峰值随之减小,而混合非球形颗粒时配位数概率密度函数分布峰值均小于不混合时的工况。【结论】混合非球形颗粒体积分数对高炉风口回旋区形貌和曳力分布、颗粒配位数概率分布等产生显著影响。