操作参数对Corex铁水Si含量的影响

优质低耗的钢铁产品需求低硅低硫的优质铁水。高硅铁水是炼钢处理所不希望的,它导致处理流程成本增加、产率降低,因此,需持续努力降低铁水中Si的含量。Corex是唯一确立并被证明已成功商业运行的改变传统高炉炼铁的熔融还原技术。尽管高炉硅转移原理已被熟练掌握,但Corex工艺仍然需要进一步的操作指导来控制硅转移。对超过一年的工厂运行数据进行统计分析,可以了解铁水中Si含量的影响因素,提供预测和控制铁水Si含量的方法。用回归分析得出回归方程来预测Corex铁水Si含量。简要讨论了硅预测回归分析中所涉及的各种因素,并验证操作参数,阐述了各参数间的相互关系。数据分析表明高水分、低金属化率、高挥发分、高渣比、高煤粉率、低产能直接导致高燃料比,同时炉渣高碱度和高Al2O3含量会导致铁水Si含量升高。     

Operating experiences with Corex and blast furnace at JSW Steel Ltd

Abstract

JSW Steel Ltd is an integrated steel plant of 3·8 mtpa capacity, with two Corex and two blast furnace (BF) units for producing hot metal. It has started its integrated steel plant operation with Corex ironmaking technology and then synergised with the conventional BF ironmaking during plant expansion. Both these ironmaking furnaces are unique in nature, and have different operation philosophies. The performances of these units depend on the raw material charged, operational philosophies, maintenance, etc., and have their own advantages and disadvantages. This paper brings out the comparison between these ironmaking processes through the usage of raw material inputs, plant operation, maintenance, quality of hot metal and byproducts. This paper also highlights the benefits due to synergistic combination of Corex and BF in an integrated steel plant.     

Raw materials for Corex and their influence on furnace performance

Abstract

The scarcity of good quality coking coal for the blast furnace (BF) has made steel makers look for an alternative iron-making process that requires little or no coke. The Corex process has been developed as an alternative to BF iron-making, which uses non-coking coal and a small amount of coke as fuel, and pellet/lump ore as iron-bearing feed. JSW Steel operates two Corex units each of 0?8 Mtpa, commissioned in 1998 and 2001 respectively. Iron oxides and non-coking coals have to meet certain physical, chemical and high temperature properties for stable operation and to attain high performance levels. Experience of the Corex operation with various coals and iron oxides over the years has helped in understanding the influence and sensitivity of raw materials on its performance and develop new raw material specifications. Statistical analysis of plant data showed that the significant parameters affecting fuel rate and production are moisture, volatile matter, char strength after reaction of coal, reduction disintegration index (RDI; %, –6?3 mm) of pellets and slag rate. This helped achieve the most efficient operating parameters, surpass rated capacity and utilise steel plant waste. The present paper brings out the impact of various raw material properties, and the modified specifications of coal and iron oxides for Corex.     

Sulphur removal in ironmaking and oxygen steelmaking

Sulphur removal in the ironmaking and oxygen steelmaking process is reviewed. A sulphur balance is made for the steelmaking process of Tata Steel IJmuiden, the Netherlands. There are four stages where sulphur can be removed: in the blast furnace (BF), during hot metal (HM) pretreatment, in the converter and during the secondary metallurgy (SM) treatment. For sulphur removal a low oxygen activity and a basic slag are required. In the BF typically 90% of the sulphur is removed; still, the HM contains about 0.03% of sulphur. Different HM desulphurisation processes are used worldwide. With co-injection or the Kanbara reactor, sulphur concentrations below 0.001% are reached. Basic slag helps desulphurisation in the converter. However, sulphur increase is not uncommon in the converter due to high oxygen activity and sulphur input via scrap and additions. For low sulphur concentrations SM desulphurisation, with a decreased oxygen activity and a basic slag, is always required.     

低硅高MgO烧结矿试验及生产

介绍了在安钢原料条件下低SiO2,高MgO烧结矿的试验及工业生产情况.以配用进口低硅高品位铁矿粉为主生产低硅高MgO烧结矿,不可避免地会引起烧结矿MgO含量的降低,从而使炼铁高炉炉渣MgO含量下降,性能变差.实验室试验和工业生产结果表明,选择适宜的烧结原料结构和工艺控制参数,可以在不影响烧结矿强度的情况下生产出SiO2较低的高品位、高MgO烧结矿,满足炼铁生产的需要.     

超大型高炉高球比低碳冶炼技术应用

为实现低碳炼铁生产,首钢基于秘鲁矿粉资源高品位低硅含量的特点,确定了高炉高球团比例冶炼的技术路线。依据炉渣碱度平衡、球团性能和炉料结构软熔性能试验研究,开发出35%碱性球团矿 + 20%酸性球团矿+ 40%烧结矿 + 5%块矿的高炉基础炉料结构。根据高比例球团矿同时抑制边缘和中心的特性,通过料序控制减少球团在边缘与中心的分布,实现酸碱性炉料的均匀混合,并采用中心加焦布料方式开放中心、适当疏导边缘,以稳定煤气分布。在活跃炉缸基础上,通过高富氧高顶压控制炉腹煤气指数来降低压差提高冶炼强度。低渣比下通过提高镁铝比至0.60~0.65来改善脱硫排碱能力。55%球团比例下高炉实现了高效稳定顺行,平均利用系数达到2.3 t/(m3·d),渣比低于220 kg/t,燃料比降至480 kg/t,炼铁系统碳排放降低8.6%。     

马钢高炉炼铁工序能耗预测模型

根据马钢高炉炼铁工序的生产数据,分析了影响马钢高炉炼铁工序能耗的相关工艺参数,并找出了影响炼铁工序能耗的关键性因素.通过分析影响炼铁工序能耗的各关键因素的相关关系及对能耗的影响规律,应用SPSS软件建立了炼铁工序能耗预测模型.另外,分析了影响焦比和喷煤比的主要因素并建立了相应的预测模型.炼铁工序能耗预测模型的可靠性高,...     

用风口耗氧量来评估某些高炉操作制度

从低碳炼铁的角度研究高炉采取的各种操作制度的合理性非常必要。用Rist模型和风口耗氧量来评估增加渣量、提高炉腹煤气量、高富氧高湿度、低硅冶炼等操作制度。研究了增加渣量不仅要增加炉渣的熔化热,而且由于风口耗氧量的增加,将提高直接还原度,提高燃料比。高富氧高湿度冶炼,由于水分解需要消耗碳素,同时附加了热量消耗,使风口耗氧量增加;唯有改善炉身效率,增加间接还原,充分利用炉内煤气热能和化学能,才能补偿风口耗氧量引起的负面影响。目前中国高炉的炉身效率普遍偏低,而低硅冶炼应在提高煤气利用率与低燃料比的基础上进行才能发挥效果。由此提出在种种操作制度下需要关注的方面,供操作者参考。     

1BF提高水渣吹制率生产实践

1BF吹制水渣采用拉萨法,工艺落后,设备故障频繁,检修工作量大,冲渣能力低,造成干渣排放量较多,增加了吨铁成本.分析排放干渣的各种原因,采取相应的措施,确保生产中干渣排放量最小化,降低渣处理费用及吨铁成本,并减少干渣排放过程造成的环境污染.     

Foaming during reduction of iron oxide in molten slag

Abstract

Coal based direct liquid ironmaking processes, also known as smelting reduction (SR) processes, are now receiving serious consideration in the industry. However, although several processes have reached pilot plant trials, only one, namely Corex, has been commercialised. In all SR processes, most of the iron oxide is reduced in the molten slag phase and foaming is an important phenomenon. Better understanding of the foaming behaviour will result in design of a more efficient and economic reactor. Accordingly, some basic studies on the foaming behaviour of some typical SR process slags have been undertaken in this work. Experimental data on foaming in a 50 kW capacity plasma reactor are discussed in this paper. The data generated are analysed in terms of foaming index, which is equal to the residence time or travelling time of the gas in the foam layer. The influence of FeO percentage in the slag, slag basicity, crucible surface area, initial slag height, and CaF₂addition in the slag on foaming has been studied.     

模拟高富氧喷煤对钒钛磁铁矿高炉冶炼中Ti,Si,V等元素行为的影响

高炉进行全钒钛磁铁矿冶炼的难点是高钛型炉渣及铁水变稠，从而带来铁水粘罐，铁损大，脱硫效果差等。其原因是ＴｉＯ２的过还原，生成了熔点极高的ＴｉＣ，ＴｉＮ，高度弥散分布于液态渣中。又由于其亲液性，形成状液。按现有生产技术水平，钒钛磁铁精矿含ＴｉＯ２１３．５％，不能单独用来炼铁，必须配加普通矿，使高炉炉渣中ＴｉＯ２含量在２４％以下。本文报告了在试验室高富氧喷煤条件下，对全钒钛磁铁矿冶炼，由于ＣＯ分压的升     

中国高炉实现低碳低成本炼铁问题探讨

针对当前国家制定的低碳方针及炼铁成本偏高、钢铁企业追求低成本炼铁的目标,采用Rist操作线法及C-rd两种方法分析了高炉炼铁过程中的碳消耗。对高炉炼铁成本进行系统分析得出:两种方法计算出的高炉炼铁碳消耗结果基本相同,误差范围在1%~2%;在ηCO55%~58%热消耗接近9 GJ/t的情况下,单位生铁的碳消耗是高炉炼铁的低碳目标,目前中国高炉的燃料比要比低碳炼铁的燃料比高出80 kg/t以上;原燃料价格低并不等于生铁成本低,应根据焦炭、煤粉、熔剂、矿石及烧结矿的综合成本来科学计算评估炼铁生产成本。由于当前产能过剩,高炉工作者应从追求产能转变为保证炉况顺行、稳定炉腹煤气量、实现低碳低成本炼铁。     

基于支持向量回归与极限学习机的高炉铁水温度预测

选取某4000 m3级别高炉2014年至2019年时间范围内的日平均数据，以铁水温度为目标函数，首先对铁水温度的特征参量进行线性与非线性相关性分析、特征选择与规范化处理，获取了显著影响铁水温度的正负相关性特征参量。在此基础上，基于支持向量回归与极限学习机两种算法对铁水温度构建预测模型，模型均可对铁水温度实现有效预测，基于支持向量回归算法构建的预测模型较优，预测平均绝对误差为4.33 ℃，±10 ℃误差范围内的命中率为94.0%。      

Mathematical Model Development of Raceway Parameters and Their Effects on Corex Process

  Corex is an alternative ironmaking process and raceway is one of the important areas to maintain the stability of the furnace. The raceway parameters are well established for blast furnace operation. But for Corex process, it has not yet been established and optimized. Thus, a mathematical model was developed to determine various raceway parameters such as RAFT (raceway adiabatic flame temperature), tuyere gas velocity and kinetic energy. The model provides an idea about the raceway geometry, zone temperature and kinetic energy accumulated in tuyere gas. Besides, all the raceway parameters have been analyzed to find out their effects on the Corex process. It is found that RAFT influences the gasification reaction kinetics and higher RAFT generates more CO in reduction gas, which improves the metallisation degree of the DRI in shaft. It is also found that increased gas velocity and kinetic energy generate more fines and demand more coke to maintain char bed permeability. High coke rate increases the production cost and lowers the production of hot metal.     

贝叶斯网络在高炉铁水硅含量预测中的应用

应用贝叶斯网络对高炉铁水硅含量进行预测。首先阐述了贝叶斯网络的数学描述,在此基础上给出贝叶斯网络预测公式的一种简化形式。然后建立高炉铁水硅含量的贝叶斯网络预测模型,对山东莱钢1 号高炉在线采集的2 000炉数据进行网络学习,离线预测取得了较好的效果。与神经网络等其他方法相比,它更适合解析高炉过程,而且透明的推理过程对高炉工长判断炉温变化趋势具有指导意义。     

Multivariable Dynamic Modeling for Molten Iron Quality Using Incremental Random Vector Functional-link Networks

Molten iron temperature as well as Si,P,and S contents is the most essential molten iron quality(MIQ)indices in the blast furnace(BF)ironmaking,which requires strict monitoring during the whole ironmaking production.However,these MIQ parameters are difficult to be directly measured online,and large-time delay exists in offline analysis through laboratory sampling.Focusing on the practical challenge,a data-driven modeling method was presented for the prediction of MIQ using the improved multivariable incremental random vector functional-link networks(M-I-RVFLNs).Compared with the conventional random vector functional-link networks(RVFLNs)and the online sequential RVFLNs,the M-I-RVFLNs have solved the problem of deciding the optimal number of hidden nodes and overcome the overfitting problems.Moreover,the proposed M-I-RVFLNs model has exhibited the potential for multivariable prediction of the MIQ and improved the terminal condition for the multiple-input multiple-output(MIMO)dynamic system,which is suitable for the BF ironmaking process in practice.Ultimately,industrial experiments and contrastive researches have been conducted on the BF No.2in Liuzhou Iron and Steel Group Co.Ltd.of China using the proposed method,and the results demonstrate that the established model produces better estimating accuracy than other MIQ modeling methods.     

宝钢炼铁技术的进步

１９９８年高炉生产稳定顺行，产量上升，喷吹煤量已达到２００ｋｇ／ｔ，烧结实现了低ＳｉＯ２生产，原料实现了智能化混匀矿堆积，焦炭质量保持良好，使宝钢炼铁的总体水平达到了世界先进水平。     

Tuyere failure analysis in Corex process

Abstract

Corex is an alternative smelting reduction ironmaking process where non-coking coal and pure oxygen is used instead of coke and air. The temperature of the tuyere region is much higher than in a blast furnace, and sustainability of tuyeres is a major challenge. At JSW Steel Ltd, almost 15% of the total shutdown is due to burnt tuyere replacement. A detailed analysis of tuyere failure and process parameters effecting tuyere burning was conducted to understand the failure mechanism and the root causes. A common reason does not exist for all types of tuyere failure; however, the collective reasons for failure are excessive coal fines (–6·3 mm) and small mean particle size, low back pressure, blocking of tuyeres, scab formation and slip.     

An Approach for Simulation of Corex Process Smelter Gasifier for Prediction of Coal Rate and Silicon in Hot Metal

A thermodynamic model for the Corex process smelter gasifier focusing on coal pyrolysis as well as on the wustite reduction has been proposed. The compositions of hot metal, slag, and the export gas of the Corex process have been simulated satisfactorily for a given degree of metallization of directly reduced iron (DRI). The minimum coal rate is linked to the given degree of prereduction of DRI and the desired final silicon content in the hot metal.     

包钢低硅烧结矿的冶金性能

 在通过红外微型烧结试验，确定温度、碱度、MgO含量及SiO2含量对包钢低硅烧结矿黏结相强度影响强弱顺序以及黏结相强度最优、较好、较差及最差的包钢低硅烧结工艺条件基础上，采用烧结杯对上述4种烧结矿的黏结相强度进行验证，并对其冶金性能进行研究。结果表明，低硅烧结的最佳工艺条件为：SiO2含量(质量分数，下同)4.0%、碱度2.5、MgO含量1.6%、配碳量3.8%。在此工艺条件下获得的包钢低硅烧结矿具有优良的冷态强度(转鼓强度83.1%)，软熔滴落性能(tS为1307.3℃，tD-tS为98℃)优于包钢烧结矿，还原性(RI为83.65%)较好。尽管低温还原粉化性与目前包钢烧结矿相当，但综合评价，包钢低硅烧结矿可以满足高炉炼铁的需求。