Research progress and future prospects in the service security of key blast furnace equipment

The safety and longevity of key blast furnace(BF)equipment determine the stable and low-carbon production of iron.This pa-per presents an analysis of the heat transfer characteristics of these components and the uneven distribution of cooling water in parallel pipes based on hydrodynamic principles,discusses the feasible methods for the improvement of BF cooling intensity,and reviews the pre-paration process,performance,and damage characteristics of three key equipment pieces:coolers,tuyeres,and hearth refractories.Fur-thermoere,to attain better control of these critical components under high-temperature working conditions,we propose the application of optimized technologies,such as BF operation and maintenance technology,self-repair technology,and full-lifecycle management techno-logy.Finally,we propose further researches on safety assessments and predictions for key BF equipment under new operating conditions.

Practice for Extending Blast Furnace Campaign Life at Wuhan Iron and Steel Corporation

One of the problems encountered in 60＇s to 80＇s of 20th century in China＇s steel industry was short life of blast furnace shaft as well as the excessive erosion of blast furnace hearth. A series of research work was carried out in order to extend blast furnace campaign life. The concept of research and development was integrated in the construction of BF （blast furnace） No. 5 at WISCO （Wuhan Iron and Steel Corporation）, and in October, 1991, the BF No. 5 was blown in. The blast furnace has worked smoothly for more than 15 years without any medium repair even guniting. It is expected that the campaign life of BF No. 5 would be longer than 16 years with a production over 11 000 t per unit inner volume （m^2）. A new blast furnace with an inner volume of 3 400 m^3 is under construction, and is designed with a campaign life of 20 years without any medium repair. The campaign life of blast furnaces in China has been extended in recent years.

Energy conservation and environment protection technologies of the blast furnace under resources deterioration conditions

In 2009,the pig iron output of China increased dramatically up to 543.75 Mt and was 15.87%higher than that in 2008,accounting for 60.53%of the world production.The processing of pig iron must consume huge amount of iron ores and coal and consequently leads to the shortage of ores and cokemaking coals supply,with prices soaring but quality worsening remarkably.How to maintain or even improve the efficiency of blast furnace production under negative conditions of constantly worsening resources of iron ore and coal has become an important scenario the Chinese ironmaking industry must face.In this paper,the production with high coal injection rate,low fuel rate and big productivity in the Wuhan Iron and Steel Corporation(Group) was introduced and revealed.The quantitative correlation between blast furnace production efficiency and diverse technical measures through combined mass-heat balances and gas-liquid counter-current flow dynamics analysis.Moreover,potential problems and countermeasures in ironmaking by feeding high Al_2O_3 and low grade iron ores were also discussed.

Formation mechanism of the protective layer in a blast furnace hearth

A variety of techniques, such as chemical analysis, scanning electron microscopy-energy dispersive spectroscopy, and X-ray diffraction, were applied to characterize the adhesion protective layer formed below the blast furnace taphole level when a certain amount of titanium-bearing burden was used. Samples of the protective layer were extracted to identify the chemical composition, phase assemblage, andistribution. Furthermore, the formation mechanism of the protective layer was determined after clarifying the source of each componenFinally, a technical strategy was proposed for achieving a stable protective layer in the hearth. The results show that the protective layemainly exists in a bilayer form in the sidewall, namely, a titanium-bearing layer and a graphite layer. Both the layers contain the slag phaswhose major crystalline phase is magnesium melilite（Ca2Mg Si2O7） and the main source of the slag phase is coke ash. It is clearly determinethat solid particles such as graphite, Ti（C,N） and Mg Al2O4play an important role in the formation of the protective layer, and the key factofor promoting the formation of a stable protective layer is reasonable control of the evolution behavior of coke.

Monitoring Method for Blast Furnace Wall With Copper Staves

A monitoring method that has been designed for the first time for blast furnace wall with copper staves manufactured in China was introduced. Combining the method of ＂inverse problem＂ and the concept ＂non-inverse problem＂, the monitoring program for blast furnace wall with copper staves has been realized, which can be used to calculate online the accretion thickness and temperature of hot surface of copper staves after obtaining the values of thermocouples of copper staves. The accretion state obtained in the actual investigation has proved that the result of the program is correct. The monitoring program shows that the accretion would easily fluctuate when the accretion layer is extremely thick or thin, thereby the stable and smooth operation of the blast furnace is hindered. By maintaining appropriate accretion thickness, both long campaigns and high productivity of the blast furnace can be achieved; furthermore, it can also optimize the operation of blast furnace and maximize its production. Approximately 30--50 mm in thickness of accretion layer is maintained on the wall of Shougang blast furnace 2, which can meet the requirement for obtaining both long campaign and high productivity.

Formation mechanism of the graphite-rich protective layer in blast furnace hearths

A long campaign life of blast furnaces is heavily linked to the existence of a protective layer in their hearths. In this work, we conducted dissection studies and investigated damage in blast furnace hearths to estimate the formation mechanism of the protective layer. The results illustrate that a significant amount of graphite phase was trapped within the hearth protective layer. Furthermore, on the basis of the thermodynamic and kinetic calculations of the graphite precipitation process, a precipitation potential index related to the formation of the graphite-rich protective layer was proposed to characterize the formation ability of this layer. We determined that, under normal operating conditions, the precipitation of graphite phase ~om hot metal was thermodynamically possible. Among elements that exist in hot metal, C, Si, and P favor graphite precipitation, whereas Mn and Cr inhibit this process. Moreover, at the same hot-face temperature, an increase of carbon concentration in hot metal can shorten the precipitation time. Finally, the results suggest that measures such as reducing the hot-face tem- perature and increasing the degree of carbon saturation in hot metal are critically important to improve the precipitation potential index.

Design and Operation Control for Long Campaign Life of Blast Furnaces

At the beginning of 1990s, Shougang blast furnaces （BFs） No. 2, No. 4, No. 3 and No. 1 were rebuilt se quently for new technological modernization in succession. The campaign life of BFs No. 1, No. 3 and No. 4 reaches 16.4, 17.6 and 15.6 years, respectively, and the hot metal output of one campaign reaches 33.8, 35.48 and 26.37 Mt, respectively; the hot metal output of BF effective volume of one campaign reaches 13328, 13991 and 12560 t/m^3, respectively, which reaches the international advanced level of BF high efficiency and long campaign life. In BF desig-ning, several advanced BF long campaign technologies were adopted. BF proper inner profile was optimized, reasona- ble inner profile was adopted, and closed circulating soften water cooling technology was applied in 4 BFs. Double row cooling pipe high efficiency cooling stave was developed which could prolong the service life of bosh, belly and stack. Hot pressed carbon brick and ceramic cup hearth lining structure were applied and optimized. BF operation was improved continuously to ensure stable and smooth operation of BF. Hearth working condition control was strengthened, burden distribution control technology was applied to achieve reasonable distribution of gas flow, and heat load monitoring was strengthened to maintain BF reasonable working inner profile. Proper maintenance at the end of BF campaign was enhanced. Hearth and bottom service life was prolonged by adding titaniferous material and enhancing hearth cooling. Gunning of lining was carried out periodically for the area above tuyere zone.

安钢4000 m^(3)级高炉炉前设备环保设施概述及改造

当今社会中,环保已经成为越来越多人关注的问题。高炉出铁场,尤其是铁口附近、渣铁沟周边的炉前区域,是整个高炉车间操作人员最多、工作条件最差、自动化程度最低的地方,也是高炉工序除尘的重点和难点。通过对炉前环保设施简单描述,分析铁口区域烟尘产生原因及分布情况,发现其中存在的不足,通过部分改造使炉前环境达到更高的环保标准。

干法除尘系统的高炉煤气管路防腐

高炉干法除尘系统在TRT之后的煤气管道极易发生腐蚀,其主要原因是高炉煤气里的氯盐溶于煤气析出水后产生酸性溶液,与管道发生了化学反应。煤气管路的防腐可以采用喷涂防腐材料、耐腐蚀的特殊管道等被动防腐方法,也可以采用控制高炉煤气的含湿量和含盐量的主动防腐方法,同时,需要在管道设计上进行优化,使煤气管道尽快排出冷凝水,减少酸性溶液与管路作用时间,以减缓高炉干法除尘系统煤气管路腐蚀。

高炉炉缸侧壁碳复合砖残余厚度和热面处保护层厚度传热模型分析

山东泰山钢铁集团有限公司(简称泰钢)1号高炉自2019年10月开炉投产以来,炉缸热电偶温度基本保持较低的温度。通过建立一维稳态传热模型计算碳复合砖的残余厚度和热面处保护层的厚度。结果表明,炉缸底部侧壁的碳复合砖侵蚀量较少,炉缸铁口中心线附近碳复合砖侵蚀量较多,高炉炉缸区域未出现“象脚状”侵蚀。高炉炉缸内保护层的厚度随着高度的增加而增大,富铁保护层易在铁口中心线以下形成,富渣保护层易在铁口中心线以上形成。碳复合砖中的主要成分氧化铝几乎不与铁水发生反应,而二氧化硅会与铁水发生反应。铁水渗透进入碳复合砖的临界孔隙为2.030μm,远大于其平均孔隙0.238μm,因此,采用碳复合砖有利于抵抗铁水的侵蚀。

南钢高炉长寿设计及管理经验

南钢1、2号高炉一代炉役寿命分别达到14.2、15.6年,3号高炉至今已生产13年,均取得了较好的长寿效果。设计上,3座高炉均采用嵌入式陶瓷杯结构,陶瓷杯嵌入风口组合砖内,在风口组合砖下方,陶瓷杯无法自由膨胀;3号高炉吸取1、2号高炉经验,采用联合软水密闭循环冷却系统,改进冷却壁的固定,从根本上解决因炉壳剪断水管而导致冷却壁漏水的问题。日常生产管理中,加强原燃料质量管理,优化操作制度,采取成熟的护炉措施,建立高炉长寿智能化监测及预警体系,维持稳定合理的煤气流分布和活跃的炉缸状态,是高炉长寿的重要保障。

炉顶均压煤气回收系统在武钢大型高炉的运用

本文详细阐述了7号高炉均压煤气回收系统设计特点、工艺流程和运行效果。对炉顶料罐煤气排放回收时间进行了精确计算,为煤气回收按照时间模式运行提供了依据,与不回收相比只增加了8.9 s的上料时间;回收煤气净化部分对洗涤塔的工作原理进行了详细介绍,回收过程中不会对煤气管网造成压力波动,并实现了洗涤水循环利用;该均压煤气回收系统煤气回收率达到76%,平均每天可回收的煤气量达66858 Nm^(3),每年回收煤气折算标准煤量为3052 t,并减少粉尘排放约237 t。

高炉炉缸铁水流场影响因素的数值模拟研究

对高炉炉缸铁水流场影响因素开展数值模拟研究。结果表明:铁水剪切应力较高区域主要集中在炉缸出铁口下方;提高高炉利用系数会增大炉缸壁面上的剪切应力;在高炉正常生产情况下,死料柱孔隙率和铁口直径变化对炉缸侧壁铁水剪切应力影响较小;增加铁口深度和减小铁口倾角可以有效降低铁水对炉缸侧壁的剪切应力。实际生产中,保持良好原燃料条件,适度增加铁口深度,采取小铁口倾角出铁有利于减缓铁水对炉缸内衬的冲刷,从而实现炉缸长寿的目标。

国内某1680 m^(3)高炉设计特点

介绍国内某1680 m^(3)高炉在高效、长寿、节能及环保等方面的设计特点。该高炉采用环保的矿槽和出铁场设计、可靠节能的炉顶装备、高效长寿的炉体设计、第二代旋切顶燃式热风炉技术、第三代环保底滤渣处理技术及BCRT鼓风机组设备,投产后取得很好的应用效果。稳定运行后,高炉各项技术经济指标均处于国内同级别高炉的领先水平。

围高炉燃料多样性对环境影响的研究

在工业生产中,尤其是在钢铁制造过程中,高炉作为关键设备之一,其燃料的选择对生产效率和环境影响有着重大影响。高炉燃料多样性指的是除了传统的焦炭之外,还包括生物质燃料、气体燃料等多种燃料的使用,旨在优化燃料消耗、降低生产成本和减少环境污染。文章通过对高炉燃料的类型与特点的综述,深入分析了燃料多样性对环境影响的三个主要方面:温室气体排放、固体废物及有害副产品的产生与处理以及通过生命周期评估方法对不同燃料环境影响的综合评价。基于这些评估进一步探讨了减缓环境影响的策略和措施,包括提高能源效率、利用清洁能源和废物管理与资源回收。通过这些策略,不仅能够减轻钢铁生产对环境的影响,为钢铁行业生产提供了可持续发展路径。

罗源闽光1号高炉停炉实践

罗源闽光1号高炉因后序工艺检修影响于2022年7月25日停炉,停炉前制定详细的停炉方案,控制合适的生铁成分及布料矩阵,停炉降料面过程中高炉工艺参数控制得当,全程进行煤气回收检测,炉内无爆震、悬料、塌料等现象,实现了安全、环保、高效地停炉。

对焦炭反应性和反应后强度规范性试验方法的研究

通过对焦炭反应性和反应后强度规范性试验方法的研究,探讨了焦炭在热反应炉内以不同试验方式下所带来不同的反应性(CRI)和反应后强度(CSR),并对其进行了分析和比较,得出焦炭CRI和CSR与摆放方式的关系、每层焦炭CRI和CSR的关系以及焦炭CRI和CSR与摆放高度的关系。

汉钢2280 m^(3)高炉护炉强化冶炼实践

为了解决2018年汉钢2280 m^(3)高炉炉缸壁温度偏高的问题而采取了一系列措施,包括提钛护炉、强化原燃料管理和更换延长风口套等。通过健全炉缸监控系统、优化操作制度和加强炉前排铁,成功使炉缸活动起来,并有效控制了侧面温度。这不仅提升了高炉的熔炼效果,还确保了安全操作,提高了经济性能,实现了护炉和生产的平衡。

中国炼铁系统的节能与环境保护

回顾了20世纪90年代以来,中国炼铁系统的节能和环境保护的进展。指出由于高炉喷煤技术的开发和推广,大大减少了焦炉的建设投资,真正从源头减少了铁前系统的能耗和污染。基于对炼铁系统二次能源的分析,从节能和减排温室气体来看,淘汰落后的小烧结、小高炉,大力推广高炉TRT、高效干式除尘和利用高炉煤气发电及烧结余热回收利用等,将是今后工作的重点。

高炉炉缸炉底长寿技术

对高炉炉缸和炉底的侵蚀机制、合理的炉缸结构、炉缸和炉底内衬结构及其耐火材料进行了较为全面的介绍,同时建议在高炉生产过程中采取一系列措施来提高炉缸、炉底的寿命:拥有合理的死铁层深度、炉缸高度和铁口深度的炉缸结构,可为高炉高效长寿和生产的稳定顺行奠定良好基础;根据高炉顺行情况和炉缸、炉底侵蚀状态控制好生铁成分,并采取有效措施减少碱金属等有害元素在炉内的富集及对炉缸、炉底的侵蚀;在线进行压浆能有效消除炉缸砖衬间的缝隙,提高炉缸冷却系统的冷却效果,减缓炉缸砖衬的侵蚀;加含钛物料护炉可以使侵蚀严重的炉底、炉缸转危为安,显著提高高炉寿命。