Numerical Simulation on Blast Furnace Operation with Hot Burden Charging

Blast furnace operation with hot burden charging was numerically simulated to preliminarily analyze its advantages and disadvantages.Multi-fluid blast furnace model was utilized to simulate hot burden charging operations under the conditions that the charging temperatures of pellet and coke were supposed separately or simultaneously as800℃.The results showed that,with hot burden charging,the furnace top temperature significantly increased in comparison to the conventional operation with cold burden charging.However,in-furnace temperature decreased,which decelerated the reduction rate of ferrous burdens.The concentrations of reducing gases were decreased in the furnace.The height of cohesive zone shifted downwards.When the charging temperatures of pellet and coke were simultaneously 800℃(PC800),coke rate,fuel rate and carbon emission rate were decreased by 13.4,22.1and19.25kg·t-1,respectively.The ratio of ore to coke,solid burden charging rate and hot metal productivity were increased by 4.79%,7.55kg·s-1 and 6.38%,respectively.Heat taken away by top gas and energy consumption per ton hot metal were increased by 68.97%and 6.40%,respectively.Generally speaking,hot burden charging was adverse to energy utilization of blast furnace.     

Mathematical simulation and experimental study on coke oven gas injection aimed to low carbon blast furnace ironmaking

Coke oven gas (COG) tuyere injection is recognised as one of effective measures to achieve low carbon blast furnace ironmaking. In this paper, simulation of blast furnace operation with COG injection was investigated by means of multi-fluid blast furnace model, and the softening-melting and dripping behaviours of mixed burden were studied on basis of simulation results. The model simulation shows that, with COG injection rate increasing, the concentration of inner-furnace hydrogen is enhanced obviously. Cohesive zone moves downwards and becomes thinner. The column permeability gets better. Hot metal productivity increases and CO₂ emission reduces. Compared with conventional operation without COG injection, when COG injection rate is 152.34?Nm³/tHM, column pressure drop is decreased by 31.5% and hot metal productivity is increased by 26.36% and CO₂ emission is decreased by 17.54%. Therefore, the simulation and experimental results reveal that it is achievable to improve blast furnace operation performance, such as hydrogen-enriched reduction, better column permeability, high efficiency, low carbon emission and so on.     

高炉喷吹还原气操作的数学模拟研究

副产煤气的高效利用对钢铁产业的节能降耗和环境保护意义重大。为此,提出了一个新的高炉风口喷吹高炉、转炉和焦炉煤气技术,并利用多流体高炉模型对其进行了详细模拟研究,预测了炉内现象和操作性能的变化。在维持回旋区温度、炉腹煤气量及渣面处铁水温度一致的条件下,模拟结果表明与现行常规操作相比,风口喷吹煤气后炉身温度下降,但整个炉内H₂/CO浓度显著提高,炉身烧结矿间接还原加速,产量明显增加,热利用效率明显改善。其中喷吹焦炉煤气效果最为显著,高炉CO₂产生量大幅度降低。随工艺氧制备等技术的进步,高炉喷吹副产煤气技术具有广阔的应用前景。     

高炉使用含碳复合炉料的原理

 高炉炼铁正朝着高产、低污染、低能耗的方向发展,为了实现这一目标,包括高炉使用含碳复合炉料等一些革新的炼铁技术已经被提出或实际应用。铁焦、热压含碳球团是将铁矿粉和煤粉按一定比例混合后制成的新型含碳复合炉料。研究结果指出,含碳复合炉料相比于传统的高炉炉料（烧结矿和球团矿）具有高温强度高、还原性能好以及原料适应性强等优势。阐明了高炉使用含碳复合炉料的基本原理,介绍了铁焦制备的工艺流程及应用情况,重点进行了热压含碳球团制备工艺流程、冷态冶金性能、高温冶金性能、高炉使用热压含碳球团等试验研究,最后利用多流体高炉数学模型对高炉使用热压含碳球团操作进行了模拟研究。研究表明,高炉使用一定量的含碳复合炉料可以降低热空区温度,增加产量,降低焦比,高炉热利用效率明显提高,操作性能得到有效改善。     

Fundamental Study on Carbon Composite Iron Ore Hot Briquette Used as Blast Furnace Burden

Carbon composite iron ore hot briquette (CCB) is the product of fine iron ore and fine coal by hot briquetting process, which attracts more and more attention as a new type of ironmaking raw materials aiming to improve the operation efficiency and reduce the coke consumption of blast furnace. This paper is devoted to experimental study on metallurgical properties of CCB and numerical simulation of the BF operation with CCB charging. At first, the metallurgical properties of CCB, including cold crushing strength, RDI, RSI, reducibility, high temperature strength, and softening and dripping are experimentally tested and compared with the common burdens, which revealed that the CCB possesses the required metallurgical properties and is suitable to use as the blast furnace burden. Then, the effects of charging CCB on the dripping properties of comprehensive burdens are elucidated based on the experiments under simulated blast furnace conditions. The results showed that the maximum charging ratio of CCB in the iron burdens is 40%–50% for achieving appropriate dripping properties of the mixed burdens. Finally, a multi‐fluid blast furnace model is used to simulate BF operation with CCB charging. According to model simulations, charging CCB will cause the temperature level to decreases in the furnace and the location of the cohesive zone shifts downward. On the other hand, the productivity tends to increase while coke rate and total reducing agent rate decrease, the heat efficiency improves remarkably and the operation performance of BF is effectively enhanced.     

高炉使用热压含碳球团操作的数学模拟研究

介绍了一种高炉炼铁新技术即高炉使用热压含碳球团技术,并利用多流体数学模型模拟该操作,对炉内现象和操作性能的变化进行了充分解析.数学模拟结果表明:热压含碳球团的使用将使得炉内温度水平降低,软熔带位置下降,但同时高炉产量增加,焦比显著降低.在一定范围内使用热压含碳球团,高炉热利用效率明显提高,操作性能将有效改善.     

从生产实践分析降低焦比的途径

总结了首钢高炉降低焦比的实际经验,得出结论：精料是高炉生产的基础,它占首钢降低焦比总量的６４．７％。讨论了喷煤、风温、铁水硅含量及装料制度对焦比的影响。     

马钢2500m3高炉原燃料劣化条件下降低焦比的生产实践

在马钢2号2500m3高炉的生产实践中为了进一步降低生铁成本,提高大型高炉的综合经济效益,针对原燃料质量持续劣化的现状,通过采取小块焦回收再利用、强化入炉料管理、改善喷吹煤质量、优化上下部调剂、稳定炉温和改善渣系、高风温及富氧综合喷吹、高顶压操作、加强炉型管理等一系列措施,使煤比大幅度提升,焦比显著降低。在燃料比无明显变化的情况下,焦比降低到320kg/t,与2012年相比,焦比降低了60~70kg/t,高炉利用系数稳定在2.4t/(m3·d)。     

Experimental study on the effect of using nut coke on the permeability of packed beds in blast furnaces

The charging pattern may affect blast furnace permeability,coke ratio,and the freedom to select low-grade raw materials. Ore-coke mixed charging is a potential technique for optimizing the charging pattern. In recent years,charging small-sized coke( nut coke) into the burden layer has been applied to save raw materials and decrease cost.Although mixed charging,especially adding nut coke into the burden layer,may have many advantages,the mechanisms and side effects of nut coke use are not well understood,and the mixing ratio is still limited in industrial blast furnace operation. In this study,the status of mixed charging,especially nut coke used in blast furnaces,was investigated. A cold flow model was established to study the permeability of the packed bed in the blast furnace "dry zone"under different conditions with the aim of better understanding the mechanisms of mixing coke and nut coke into the burden layer. The effect of coke size,mixing coke ratio,layer numbers,and gas flow rate on the pressure drop of the packed bed was investigated. The experimental results show that mixing the nut coke in the ore layers decreases the pressure drop to different extents depending on mixing ratio.     

Numerical Evaluation of Blast Furnace Performance under Top Gas Recycling and Lower Temperature Operation

The new process of top gas recycling by hot reducing gas (HRG) injection has been developed in this study in order to overcome the disadvantageous problems under the lower temperature operation, to enhance the utilization of top gas carbon and to reduce carbon dioxide emission of blast furnaces. Numerical evaluation of blast furnace top gas recirculation together with lower‐temperature operation was performed by means of a multi‐fluid blast furnace model. The simulation results show that, (1) under the lower temperature operation, the shaft injection, or simultaneous shaft and tuyere injection of hot reducing gas is effective to increase the heat supply and to enrich the reduction atmosphere in the shaft zone, to improve the reduction of iron burdens, and enhance the efficiency of the shaft zone. (2) If top gas is recirculated by HRG on the basis of lower temperature operation, a highly efficient low‐carbon blast furnace is obtained. The productivity of the furnace shows a remarkable increase and the total reducing agent rate shows a considerable decrease. Furthermore, the top gas carbon utilization is enhanced and the carbon dioxide emission rate is lowered. (3) Generally, shaft efficiency, carbon emission and heat efficiency under simultaneous tuyere and shaft injection are comparatively better than in the other two methods of single injection.     

焦炉煤气与O2裂解时竖炉产量的热力学计算

 竖炉还原工艺中焦炉煤气(COG)的消耗量可影响金属铁产量,为了明确O₂裂解时焦炉煤气消耗量与竖炉产量的关系,对理想条件下焦炉煤气在竖炉还原工艺中的消耗量和金属铁产量进行了热力学计算。计算结果表明,竖炉生产过程中,作为热源的焦炉煤气消耗量大于作为还原剂的消耗量。补充竖炉内热需求量的方法有两种,补偿方式不同,金属铁产量的变化趋势也不同:直接补充重整焦炉煤气时,金属铁的产量随生成温度的升高而降低,120万t焦炉产生的焦炉煤气在金属铁生成温度为850和900 ℃时,相应的竖炉生产能力分别为50.72万和49.90万t/a;先采用煤气自重整技术再补充额外焦炉煤气时,随金属铁生成温度的升高,金属铁的产量先增大后减小,120万t焦炉产生的焦炉煤气在金属铁生成温度为845和900 ℃时,相应的竖炉生产能力分别为56.69万(最大值)和55.68万t/a。研究内容及结果可为实际的竖炉工艺选择合理的操作参数提供理论指导和依据。     

Numerical Evaluation on Lower Temperature Operation of Blast Furnaces by Charging Carbon Composite Agglomerates

This paper places emphasis on evaluating ironmaking operation at lower temperature. Blast furnace operation with carbon composite agglomerates (CCB) charging and/or lower operation temperature has been numerically examined using a modified multi‐fluid blast furnace model under constant thermal conditions of the raceway. The numerical calculation shows that a lower in‐furnace temperature level is achieved under the operation with the CCB charging. With CCB charging, the location of the cohesive zone shifts downward and the temperature of the thermal reserve zone decreases. The decrease in heat requirements for solution loss, sinter reduction and silicon transfer reactions compensates the increase in heat demands for CCB reduction and direct reduction, and rather improves the efficiency of blast furnaces. Consequently, the productivity improves, the coke rate shows a notable decrease and the total reducing agent rate also tends to decline compared with conventional operation without CCB charging. Therefore, charging carbon composite agglomerates contributes to the enhancement of blast furnace performance. Furthermore, the model predicts that higher operation efficiency is achieved if the melting and/or tapping temperature could be dropped. The innovative technology of lower temperature ironmaking is expected to be applied in industrial blast furnaces after resolving the problems in engineering and economic evaluations.     

高炉喷吹焦炉煤气技术的研究进展

综述了国外高炉风口喷吹焦炉煤气(COG)技术的研究进展,包括瑞典律勒欧使用风口理论模型模拟高炉风口喷吹焦炉煤气,奥钢联林茨厂和维也纳大学联合对高炉风口采用单、双枪喷吹焦炉煤气的模拟研究,以及喷吹焦炉煤气时在炉子下部形成CO和H2的还原能力分析。介绍了日本高炉炉身喷吹焦炉煤气的基础研究。也介绍了喷吹焦炉煤气的工业高炉及相关结果,其经验可供钢铁企业鉴借。     

高炉喷吹除尘灰的研究

 由于高炉除尘灰含有大量的铁和碳,且其排放造成严重的环境污染,因此通过现有的喷煤系统将其作为含铁原料和含碳原料从风口喷入高炉无疑是处理除尘灰的一种有效途径。考虑到喷吹除尘灰影响到炉内炉渣的碱度、铁水的硫含量、理论燃烧温度和焦比的变化,通过高炉物料平衡和局部热平衡模型计算了焦比、炉渣碱度和理论燃烧温度随喷入除尘灰量的变化,为高炉操作提供理论依据,并进行了工业试验。结果表明,焦比和炉渣碱度随除尘灰喷入量的增加而下降,而理论燃烧温度则变化不大,这些变化可以通过调整配料来应付;喷吹除尘灰后高炉透气性略有下降,所需喷吹压力增大,试验证明高炉喷吹自身的除尘灰是可行的。     

济钢一铁提高喷煤量实践

济钢一铁通过优化炉料结构,加强筛分,改进高炉操作,上部采用大矿批为主的装料制度,下部实行高风速、全风温、全风口喷吹等操作,同时不断加大喷煤系统和热风系统的设备改造,推动高炉喷煤比稳步提高,１９９８年喷煤总量达到了１８．１万ｔ。     

高炉富氧喷吹焦炉煤气理论研究

 用计算模拟富氧喷吹焦炉煤气以后高炉直接还原度、焦比、入炉风量、炉腹煤气量、理论燃烧温度和炉顶煤气的变化,同时分析了富氧喷吹焦炉煤气对高炉冶炼可能带来的影响。计算结果表明：在保证高炉热量和理论燃烧温度满足高炉正常生产前提下,选择合适的富氧率和焦炉煤气喷吹量,可以使焦比降低至291kg/t,CO2的排放量减少6.1%,并且提高了煤气利用价值,增加企业的经济和环境效益。     

Numerical Simulation of Innovative Operation of Blast Furnace Based on Multi-Fluid Model

To date ,blast furnace operators have a relative-ly good understanding of internal mechanisms ,andno longer treat blast furnace as a“black box”. Forthe blast furnace , however , one of the most com-plex metallurgical units inthe field of chemical engi-neering,the complexity keeps proliferating with theadoption of newtechnologies ,such as high rate in-jection of pulverized coal ,effective use of carbona-ceous andferrous materials ,and so on.If merely bydirect instrumentation and empirical kno…     

柳钢4号2 000 m3高炉炉役后期布料制度探索实践

阐述了柳钢4号2 000 m3高炉布料方式的特点。为了解决原燃料质量一般和后期炉役护炉生产条件下炉况长期稳定顺行的问题,4号高炉采用大角度、大角差结合中心加焦布料方式,其核心要点是适当压制边沿气流,发展中心气流。柳钢4号高炉生产实践表明,采用大角度、大角差结合中心加焦布料方式,边沿汽流相对较重,边沿十字测温温度在150 ℃以下,但是由于中心加焦的作用,中心煤气流较旺盛,高炉顺行状态良好。     

高炉块状带焦炭劣化机理

 模拟高炉块状带气流和温度条件,研究了粒度、熄焦方式和焦炭类型对焦炭劣化影响,以及高炉上部碱金属K2CO3和Na2CO3催化焦炭与CO2的反应机理。结果表明：小粒度焦炭和湿熄焦炭失碳率较高,产生的粉末量多;捣固焦炭在反应开始时劣化程度低于顶装焦炭,随着反应时间增加,劣化程度高于顶装焦炭;碱金属会与焦炭中的灰分形成催化复合物,导致焦炭与CO2反应的起始温度降低,破坏焦炭的微晶结构,失碳率增加,粉化加重;K2CO3的催化作用高于Na2CO3的催化作用。     

Steady heat transfer in melt-irrigated blast-furnace zone

The steady heat transfer in the irrigated zone of the blast furnace is considered, taking account of the filtration of hot metal and slag through the coke bed. In this zone, the fluxes of coke, hot metal, and slag are heated simultaneously and exchange heat with one another, by both convection and radiation. Convection ensures heat treatment between the gas and all the batch materials and also between the slag and coke, since the slag running through the coke partially covers its surface. Radiant heat transfer develops among the coke, hot metal, and slag. It is more intense at higher temperatures. The heat transfer among the coke, hot metal, and slag in the irrigated zone of the blast furnace has a considerable influence on the temperature field in this zone. To calculate the heat transfer at the shoulder and hearth, information is required regarding the distribution of the thermal effects of direct reduction of iron, silicon, and manganese over the height of the irrigated zone and the proportion of the coke surface covered by slag.