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.

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.

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.

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。

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。

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。

高炉风口回旋区影响因素的冷态实验分析

以重钢5号高炉实际尺寸和操作参数为基础,假设高炉风口未喷吹煤粉,回旋区内的流动为气固两相流动,且气相的流动属于粘性不可压缩流动,根据相似理论建立了高炉回旋区三维冷态实验模型,分析回旋区的形成机理及影响因素。结果表明:鼓风量、料层物理属性、料层高度以及风口直径对回旋区大小和形状均有影响。随着鼓风量的增大,回旋区穿透深度和高度均不同程度的增加,当鼓风量过大时,回旋区顶部炉料上浮,椭球形的回旋区形状不再存在。同一鼓风量下料层的粒径与密度比越大时形成的回旋区穿透深度越小,反之越大。料层高度对回旋区穿透深度的影响不大。风口直径对回旋区穿透深度的影响较明显。

高炉三维气固湍流和煤粉燃烧过程数值模拟

基于欧拉气相方程组、欧拉颗粒连续方程和动量方程以及拉氏颗粒能量和质量变化方程,建立并发展了高炉风口回旋区湍流气固两相流动和煤粉燃烧的三维数学模型。用所建模型分别对冷态模型内气固两相流动和某企业750 m3高炉风口回旋区内的气固两相三维流动与煤粉燃烧进行了数值模拟。采用三维激光相位多普勒分析仪(PDA)对冷态模型内气固两相流场进行了测量,实验结果与冷态两相流动的模拟结果基本一致。热态模拟结果给出了气相温度和组分浓度分布,模拟结果与实验测量结果较吻合,揭示了风口回旋区内气固两相流动和煤粉燃烧的基本性质和特点。

高炉喷吹焦炉煤气风口回旋区的数学模拟

基于质量平衡和热量平衡理论,建立了高炉喷吹焦炉煤气风口回旋区数学模型,系统研究了焦炉煤气喷吹量对回旋区焦炭质量流量、理论燃烧温度、炉腹煤气量、炉腹煤气组成和回旋区形状的影响.研究表明:在维持高炉现有的基准操作不变的条件下,随着焦炉煤气喷吹量的增加,理论燃烧温度呈降低的趋势,而炉腹煤气量呈增加的趋势;为了维持理论燃烧温度和炉腹煤气量与基准操作一致,可通过降低风量和提高富氧率进行热补偿.热补偿后,随着焦炉煤气喷吹量的增加,焦炭质量流量呈上升趋势,炉腹煤气中还原气体积呈增加趋势,回旋区体积呈缩小趋势.每增加1 m3/s的焦炉煤气喷吹量,焦炭质量流量上升1.74%,炉腹煤气中还原气体积增加2.04%,回旋区体积缩小1.98%.

高炉回旋区影响因素的冷态模型研究

以重钢5号高炉实际尺寸和操作参数为基础,假设回旋区内的流动为气固两相流动,且气相流动为粘性不可压缩流动,根据相似理论建立了高炉回旋区三维冷态实验模型,分析了回旋区形成机理的影响因素。结果表明:鼓风量、料层属性、料层高度以及风口直径对回旋区大小和形状均有影响。随着鼓风量的增大,回旋区深度和高度均不同程度的增加,当风量过大时,回旋区炉料上浮,椭球形的回旋区形状不再存在。回旋区高度随料层高度的逐渐增加而减小。风口直径对回旋区穿透深度的影响较其对高度的影响明显。

鞍钢2号高炉合理鼓风动能的探讨

简要分析了高炉鼓风动能的影响因素及判定方法,基于鞍钢2号3200m^3高炉生产数据的统计分析,重点探讨了2号高炉合理鼓风动能的范围和鼓风动能的控制方法。分析结果表明:高炉要取得低燃料比和高产量的效果决定于合理的鼓风动能,可以通过控制合理的人炉风量和送风比、控制合理的风口面积、调整富氧率,以及提高原燃料条件来获得合理的鼓风动能。针对鞍钢2号3200m^3高炉而言,合理的鼓风动能范围为110~130kJ/s,合理的送风比范围为1.75~1.80,合理的风口回旋区长度应在1.82m左右。

氧气高炉新型氧煤燃烧器设计参数对风口区流场影响数值模拟

氧气高炉通过向风口回旋区喷吹煤粉以及脱除CO_2的循环高炉煤气,可有效降低CO_2排放。运用CFD商业软件,建立风口回旋区三维模型,针对氧气高炉所设计的新型燃烧器中氧煤枪数量及其与直吹管所呈角度和空间物理位置对风口回旋区流场的影响进行数值模拟。研究结果表明：采用单支氧煤枪操作,当其位于直吹管上部时,煤气流速度随喷吹角度由7°～15°变化时逐渐减小,且夹角为9°较为适宜,当其位于下部时,随着夹角越大,对风口回旋区深度增加越有利;采用双氧煤枪操作,当其在直吹管上下、左右分布时,夹角分别为11°和13°较合理;当单支氧煤枪位于直吹管上方且夹角为9°、距离d为75 mm时能较好地促进风口回旋区深度增加并保持足够的鼓风动能。

高炉风口回旋区工作状态监控技术的研究现状

在高炉生产过程中,只有从风口窥视孔可以直接观察高炉内的情况,操作者十分关注高炉风口区的工作状况,并将其作为判断和控制高炉操作的重要依据之一.风口前的监测可以获得喷煤高炉在风口处煤粉输送情况,还可以根据风口亮度与煤粉燃烧数值模拟结合,研判煤粉在风口回旋区的燃烧状况及温度分布等.简述了国内外在高炉风口回旋区温度检测、工作状态的监控技术的研究现状,提出利用数字图像处理技术与数值模拟结合,解决高炉风口回旋区工作状况监测和控制的思考.