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.     

Progress in Technologies of Vanadium‐Bearing Titanomagnetite Smelting in PanGang

The smelting of vanadium‐bearing titanomagnetite by blast furnace was very difficult because the content of TiO₂ of blast furnace slag could amount to 20‐25%. After long term development and continuous improvement, special intensified smelting technologies for vanadium‐bearing titanomagnetite by blast furnace were obtained and improved gradually. With the improvement of beneficiated material and equipment, smelting intensity has been increasing gradually and the highest comprehensive smelting intensity that is fuel comsumption per unit useful volume per day reached 1.45t/(m³·d). Technical‐and‐economic indexes of blast furnace have also been increasing remarkably. The highest monthly utilization coefficient exceeded 2.7t/(m³·d) on the condition that the burden total ferrum grade was only about 50%.     

Numerical simulation on novel blast furnace operation of combining coke oven gas injection with hot burden charging

A novel blast furnace operation of coke oven gas (COG) injection simultaneously with hot burden charging has been proposed to solve the problem of insufficient heat in the BF shaft zone under the condition of COG injection and make full use of the abundant sensible heat of high temperature burden. In this paper, the novel process has been simulated with a multifluid blast furnace model. The results show that, in comparison with the operation of COG injection only, under the operation of COG injection together with hot burden charging, the temperature in the upper zone of the shaft increases while that in lower zone decreases. Furthermore, the reduction of iron bearing material is improved in the top zone, and the cohesive zone tends to descend and narrow. The coke ratio, fuel ratio and CO₂ emissions of the operation of charging hot pellet and coke with the temperature of 800°C are decreased by 4.0, 4.7 and 5.3% respectively, while the hot metal productivity is increased by 7.14%. Therefore, COG injection combined with hot burden charging operation not only increases temperature in the upper part of the blast furnace but also decreases energy consumption per tonne hot metal.     

高炉喷吹COREX脱CO2顶煤气的数值分析

 COREX脱CO₂顶煤气作为一种优质富氢气体,直接喷吹进入高炉可有效降低高炉燃料消耗。建立了高炉喷吹COREX脱CO₂顶煤气静态工艺模型,研究高炉喷气对风口理论燃烧温度、炉腹煤气量、炉腹煤气成分、风口回旋区形状、直接还原度、节焦效果等因素的影响,并进一步探究了提高风温作为热补偿措施后的适宜喷气量。研究结果表明,不采取热补偿措施条件下,随着COREX脱CO₂顶煤气喷吹量的增加,理论燃烧温度逐渐降低,炉腹煤气量逐渐升高,高炉直接还原度降低。以维持理论燃烧温度和炉腹煤气量稳定为标准,风温相对基准提高30、60、90 ℃后,可接受喷吹的煤气量为45.4、85.5、123.3 m3/t。热补偿后,随着喷气量增加,鼓风量逐渐降低,富氧率逐渐升高。炉腹煤气中的CO及H₂含量随喷气量增加而增加,每增加10 m3/t的COREX煤气喷吹量,炉腹煤气中总的还原气体体积分数增加0.46 %,直接还原度降低0.006,节约焦炭1.48 kg/t。     

Analysis on Non‐Uniform Gas Flow in Blast Furnace Based on DEM‐CFD Combined Model

Blast furnace technology is currently aiming at low reducing agent operation so as to decrease CO₂ emissions. At the same time, the inner volume of blast furnaces has frequently been enlarged so as to increase production rate in some countries, including Japan. Operating conditions designed for low reducing agent in a large blast furnace tend to cause unfavorable phenomena such as slipping of the burden and gas channeling due to the decrease in coke rate. Mathematical models help to clarify the in‐furnace phenomena under these situations. From the above backgrounds, a new model has been developed that combines Discrete Element Method with Computational Fluid Dynamics (DEM‐CFD) to simulate precisely the gas flow and solid motion in a blast furnace. The present study aimed to develop a three‐dimensional mathematical model based on DEM‐CFD for simultaneous analysis of gas and solid flow in the whole blast furnace. The unbalanced gas flow in the case of clogging of the particular tuyere was analyzed to clarify the circumferential unevenness in the lower part of the blast furnace. Based on the combined DEM with CFD model, the non‐uniform gas flow in the lower part of the blast furnace was precisely evaluated.     

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…     

全氧高炉风口喷吹烧结烟气的冶炼特征

摘要：建立了高炉或氧气高炉喷吹烧结烟气的数学模型,实现对烧结烟气利用与处理的目的。模拟结果显示：当烧结烟气喷吹温度为1250℃,全氧高炉的炉缸与炉身处各循环200m3/t炉顶煤气时,烧结烟气喷吹量每增加100m3/t,高炉理论燃烧温度降低约134℃,直接还原度增大0.02。随着烧结烟气喷吹量的增加,煤比逐渐增大,炉顶煤气中氮气含量逐渐增大,SO2浓度逐渐降低。当烧结烟气喷吹量达到894m3/t时,炉顶煤气中的SO2质量浓度为214.28mg/m3,与普通高炉相比,降低约1.48mg/m3;氮氧化物质量浓度为45.42mg/m3,低于普通高炉约6.36mg/m3。     

武钢5号高炉专家系统在布料状态评估中的应用

高炉布料调剂对于维持高炉的稳定顺行具有决定性的意义。武汉钢铁(集团)公司新开发的5号高炉专家系统利用数学模型实现了高炉布料调剂的自动处理,通过利用数学模型处理高炉操作数据,如炉顶煤气温度、炉顶煤气成分、压差、冷却壁温度变化等,可以获得对气流分布状况、炉型变化状况及高炉运行状况的评估结果;结合高炉当前的运行状况,如焦比、风量、炉身静压力、原料状况(组成、粒度、热性能等)等就可以获得调剂的建议。高炉冶炼专家系统投入运行后,有效指导了高炉的布料调剂,高炉操作稳定,工艺指标得到改善。     

Theoretical Approach to Change Blast Furnace Regime With Natural Gas Injection

The operation of blast furnace using natural gas and oxygen enriched blast (composite blast technology) is considered in many countries to be standard operation for a modern blast furnace particularly in certain countries with cheap and stable supply of natural gas. The theoretical flame temperature (TFT) of combustion and the degree of direct reduction of iron oxides (r_d) arc considered as the main controlling parameters of composite blast technology. The calculated values of these parameters are mainly dependent on the amount of air blast consumption. This amount of air blast is measured before entering into blast stoves. Actually, some of air blast is lost through valves of air stoves. Consequently, the real volume of air blast in the furnace is less than the recorded value by amounts of 5% ? 15% which is not considered in the estimation of r_d and TFT. The purpose is to analyze the different methods for estimation of air blast inside the blast furnaces and develop a theoretical model to calculate air blast consumption with high accuracy. Based on the calculation of air blast consumption, a complete roadmap is demonstrated to change the operation regime parameters of blast furnaces working on composite blast technology.     

Preparation of blast furnace burdens with middle-low basicity from high-SiO2-content iron concentrates by composite agglomeration process (CAP)

With the depletion of high-grade iron ores, iron and steel companies all over the world are expected to use refractory iron ore resources in the sintering process. Composite agglomeration process (CAP) was utilised to improve the sintering performances of high-SiO₂-content iron concentrates in this study. Theoretical calculation indicates that CAP is more effective for the agglomeration of high-SiO₂-content iron concentrates compared with traditional sintering process (TSP). The sintering pot tests results showed that the sintering yield of 74.15 wt-%, tumbler index of 72.75 wt-% and productivity of 1.54 t·(m²·h)^?1 were achieved, which is 9.12 wt-%, 10.70 wt-% and 0.45 t·(m²·h)^?1 higher than that by TSP, respectively. Moreover, CAP decreased the solid fuel consumption by 11.77 kgfuel/tproduct. Researches of metallurgical performances showed the CAP product can be used as high-quality blast furnace burdens. This investigation provides an effective route to utilise the inferior high-SiO₂-content iron concentrates.     

首钢高炉送风制度的基础研究

随着首钢高炉技术经济指标的提升,原用的送风制度经验公式已不适应于目前的冶炼条件。结合首钢高炉冶炼现状,对送风制度方面的高炉入炉风量、实际风速、鼓风动能及炉缸煤气量、理论燃烧温度、理论实际煤气流速、透气阻力系数等计算公式进行了重新量化,提出了简化算式,由此也深化了目前冶炼条件下对高炉送风制度现状的认识。     

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.     

晋南钢铁高炉喷吹富氢气体工业化实践

 钢铁工业是中国制造业中碳排放量最高的行业,碳排放占全国碳排放总量的15%左右。高炉是钢铁工业碳消耗量最大的工序,碳消耗占钢铁流程总碳消耗的70%以上,减少高炉冶炼碳消耗是降低钢铁工业碳排放的最有效措施。高炉喷吹富氢气体不但可以提高冶炼效率,减少污染物排放,而且可以减少焦炭或煤粉消耗,从源头上降低高炉冶炼碳消耗,从而减少碳排放。以山西晋南钢铁两座1 860 m3高炉风口喷吹富氢气体工业化生产数据为例,详细研究了高炉喷吹富氢气体对燃料比、风口理论燃烧温度、炉腹煤气量、H₂利用率以及CO₂排放量的影响。结果表明,喷吹富氢气体可以显著降低高炉固体燃料消耗,在吨铁富氢气体喷吹量为65 m3条件下,富氢气体与固体燃料的置换比为0.49 kg/m3;风口喷吹富氢气体降低了风口理论燃烧温度,吨铁每喷吹1 m3富氢气体,风口理论燃烧温度降低约1.5 ℃,高炉鼓风量和炉腹煤气量都少量降低;喷吹富氢气体以后,炉内H₂的利用率平均为37.3%,CO的利用率约为43.2%;吨铁CO₂排放量可以降低80 kg左右,高炉CO₂排放降低了5.6%,取得了较好的经济、环境和减污降碳效果。     

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。     

Blast Furnace Operating Conditions Manipulation for Reducing Coke Consumption and CO2 Emission

A comparative reduction behavior of wüstite samples prepared from iron ore sinter was investigated to find the optimum way for reducing coke consumption and CO₂ emission in blast furnace technology. A series of wüstite reduction experiments was carried out using different gas mixtures. A correlation between the experimental results and real data of blast furnaces at Egyptian Iron and Steel Company (EISCO) was demonstrated in order to optimize the coke consumption inside blast furnaces. Different theoretical models were applied on real data of blast furnaces to calculate the effect of operation parameters on the coke consumption. It was found that the wüstite reducibility can be controlled and enhanced using certain ratio of H₂ and CO gases. Such kind of enhancement decreases the remaining quantity of unreduced wüstite which descends to the high temperature region of blast furnace. The theoretical analysis of real data using certain values of H₂ and CO shows that increasing the amount of natural gas injection in blast furnace of EISCO will decrease the degree of direct reduction of iron oxide and consequently will decrease the amount of coke consumption.     

Comprehensive analysis on material and exergy balances of oxygen blast furnace

The OBF process is widely studied as an alternative ironmaking process, due to the social pressure of energy and environment at present. A comprehensive mathematical model of the OBF process is established, which is based on material and exergy balances. The process parameters of the OBF with different oxygen enriched blast were calculated through the model. The calculation results demonstrated that the material balance of carbon input in the OBF process decreased by 6.7% (OBF-I) and 22.4% (OBF-II) compared to the TBF process. Also, the industrial oxygen consumption increased from 185.88?m³ (OBF-I) to 228.32 m³ (OBF-II). The exergy output and the total exergy loss of the OBF-I process decreased by 1.5% and 5.6%, respectively, and those in the OBF-II process decreased by 16.60% and 30.81%. Due to the exergy indices in OBF-II process all improved, the OBF-II process was a significantly efficient ironmaking process compared to the TBF.     

高炉使用铁焦的㶲分析

 中国钢铁生产主要以高能耗和高排放的高炉-转炉长流程为主,节能减排压力较大。因此,积极研发高炉低碳炼铁技术,促进高炉工序CO₂减排尤为重要。铁焦是将含铁原料加入适宜的煤中,经焦化或炭化后成型的新型碳铁复合炉料,其高反应性可以显著降低热储备区温度、降低碳消耗,高炉使用适量的铁焦可实现一定程度的节能降碳。基于现场生产数据,采用㶲分析理论,建立高炉使用铁焦的㶲平衡模型,探索铁焦添加量对高炉物料消耗及能量利用效率的影响。结果表明,高炉使用铁焦后,炉内间接还原得到发展,碳利用率提高,炉内灰分量降低,冶炼单位生铁的碳素消耗和炉渣量均会降低,与未使用铁焦相比,高炉使用114 kg铁焦后,吨铁碳素消耗降低25.95 kg,渣量降低11.28 kg。此外,铁焦内部的金属铁仅需熔化,节省还原所需的㶲量,焦炭和鼓风带入㶲会显著降低,因此高炉冶炼吨铁消耗的总㶲量降低,同时,炉内传热也得到改善,内部㶲损失有效降低,与未使用铁焦相比,高炉使用114 kg/t铁焦后,目的㶲效率由46.14%提高至48.87%,热力学完善度由87.46%提高到88.02%。在此条件下,高炉吨铁的内部㶲损失降低192.63 MJ,实现节能6.57 kg(标煤)。     

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。     

Thermodynamic Behaviour of Chlorine in CaO‐SiO2‐MgO‐Al2O3(‐CaF2) Slags

The solubility of chlorine in CaO‐SiO₂‐Al₂O₃‐MgO(‐CaF₂) slag was measured at 1673 ‐1823 K. By estimating the chloride capacity of slags, thermodynamic behaviour of chlorine in the molten slag was investigated. Chloride capacity increased with increasing CaO / SiO₂ ratio (C/S). An increase in MgO content decreased chloride capacity at C/S≥1.0 because it lowered the activity of Ca²⁺ which seemed to have strong affinity with Cl^? in molten slag. Also, the chloride capacity decreased with increasing Al₂O₃ content. The affinity between the Ca²⁺ and Cl^? ions was confirmed by measuring the infrared spectra of slags. The dissolution reaction of chlorine into slag was exothermic and its molar enthalpy was evaluated from the experimental results at 1673 ‐ 1823 K. Based on the result obtained in the present study, the quantitative prediction of chlorine distribution during the blast furnace process was performed. It was estimated that almost all chlorine in the blast furnace would be absorbed into molten slag even if the PCI ratio was increased or low quality coal with chlorine content less than 1.0 mass% was injected.     

韶钢4号高炉高压操作的实践

高压操作是强化高炉冶炼的一项重要措施 ,利于高炉炉况稳定顺行 ,提高煤气利用率 .韶钢 4号高炉生产实践表明炉顶压力每提高 1 0Kpa ,可增产 3.41 2 % ,降低焦比 1 .38% .