用于BOF过程中动态终点控制的新取样方式和分析方法(英文)

为了实现缩短出钢时间从而提高碱性氧气转炉(BOF)的生产效率,与熔融分析控制相关的过程如停吹、提枪或倾炉都要避免。为了达到这个目标,建立了一种用于控制BOF过程的新方法。该方法采用了一种新颖的、可在吹炼过程中进行炉渣和钢同时收集的非均相取样器,并应用了为此专门设计的激光分析方法(LIBS)。使用该方法,目标是尽可能快地完成非均相取样器收集的炉渣和钢的分析(Fe,C,P,S等元素)。除了建立非均相临线取样方法外,还建立了一种基于LIBS的特殊分析程序,当分析过程中移动非均相样品时,用于识别来自炉渣和钢的激光     

转炉熔池搅拌效果的影响因素

采用1∶10水力学模型对100t氧气顶吹转炉进行了实验研究。通过多点测量的方法,研究了枪位,喷头类型和炉型对混匀时间的影响。结果表明,熔池搅拌效果最好的区域是熔池表面,其次是熔池底部中心和熔池侧壁底部,搅拌效果最差的是熔池环流中心附近。20°氧枪对应的熔池整体搅拌效果最好。在熔池液面处采用圆弧形的炉壁结构能够改善熔池搅拌效果,缩短混匀时间。     

Effect of nozzle twisted oxygen lance on flow field and dephosphorisation rate in converter steelmaking process

The stirring ability and flow field characteristic of conventional and nozzle twisted oxygen lance (Twisted angles are 4°, 8° and 12°, respectively) on the molten bath were analysed. The mixing time, impacting depth and impacting radius are measured. Flow field characteristics of multi-phase flow are calculated by numerical simulation. Compared with conventional oxygen lance at industrial application research, it shows that the 8° oxygen lance could stir molten better in steelmaking process for the 120t dephosphorisation converter. These findings agree well with the experimental results of the water experiments and the numerical simulations. Finally, an optimal twisted angle is determined.     

Effect of MgO content in slag on dephosphorisation in converter steelmaking

Abstract

In this study, the effect of MgO content in slag on the phosphorus distribution ratios, and the equilibrium solubility of MgO in slag during converter steelmaking were analysed using the modified Kozheurov regular solution model and the thermodynamic package FactSage. Thermodynamic analysis shows that the MgO content in the final slag should be greater than 5% to saturate the slag with MgO and minimise the chemical wear of the refractory lining. However, the phosphorus distribution ratio decreases dramatically with increasing MgO. Industrial tests were performed using an 80-t top-and-bottom combined blown converter showed that the average phosphorus distribution ratio reduces significantly from 120.7 to 75.7 when the average MgO content in the final slag increases from 7.0 to 9.8%, due to thermodynamics and kinetics reasons. By optimizing the MgO content between 6 and 8% dephosphorisation and refractory wear are optimised.     

韶钢转炉尘泥利用工艺的改造

介绍韶钢转炉尘泥原压滤脱水、泥饼汽车输送烧结利用工艺所存在问题和采用管道输送至烧结利用工艺对原工艺进行改造所获得的显著环境效益和经济效益的分析 ,说明改造后的工艺与原工艺相比 ,具有投资省、运行成本费低、工艺简单实用、先进可靠等优点     

复吹转炉炼钢过程数学模拟:动力学模型

在对复吹转炉冶炼过程的机理分析的基础上,应用冶金热力学、动力学、传输原理和反应工程学理论,建立了描述冶炼过程的动力学模型,确定了模型的有关参数.作为模型的关键,根据钢中各元素竞争氧化反应的Gibbs自由能估算了吹入熔池中的氧参与各元素氧化反应的分配比率.     

A static approach towards coke collapse modelling in blast furnace

Abstract

Burden distribution control in a blast furnace has a close relationship with wind acceptance and gas utilisation. Quantification of radial distribution of ore and coke is important for proper control of blast furnace operation. Charging of metallic burden over a layer of coke causes a portion of the coke layer to get dislodged from its original position, similar to the situation observed when a heavy material is dropped on a bed of lighter particles. This phenomenon, designated 'coke collapse', significantly changes the ore/coke distribution in the radial direction and thus affects the permeability of the furnace shaft. In the present work a mathematical model for quantifying the amount of coke collapse has been proposed on the basis of 'stability of slope theory'. The calculation from this model has been compared with the results from experiments in simplified physical models. Predictions of the mathematical model are in good agreement with experimental results.     

应用炉气分析的转炉动态模型初步研究

运用物料平衡及反应平衡原理,利用炉气连续分析的数据,建立了转炉冶炼过程的动态模型.本模型的计算结果表明:(1)通过烟气流量、成分及原料中初始碳含量可动态地确定熔池中的碳含量;(2)以动态确定的碳含量为基础,经过热力学平衡分析,可确定熔池内温度及氧含量的动态变化.     

180t转炉炉衬的损毁原因分析

对某钢厂180 t顶底复吹转炉大修时炉衬的损毁情况进行调查,应用偏光显微镜和电子探针对炉衬镁碳质残砖的微观结构和物相组成进行分析,指出其损毁的原因为石墨被氧化→炉渣侵入砖中→方镁石与渣发生反应→耐材熔出→镁碳砖损毁。     

应用炉气分析预测转炉吹炼终点碳含量

应用炉气分析预测转炉吹炼过程中熔池碳含量的变化,并对吹炼终点时的碳含量和脱碳速率、氧枪枪位的关系进行了研究,得出如下结论:(1)碳积分模型只适合入炉原料数据准确的情况下,对终点碳含量进行预测;(2)吹炼末期,碳含量和脱碳速率的关系可用三次方函数描述;(3)为排除枪位对数据拟合的影响,对于恒压变枪位吹炼,在不同的枪位下调整三次方模型参数,即可实现对终点高、中、低碳含量进行预测.     

复吹转炉炼钢过程脱碳模型

通过分析复吹转炉脱碳过程的冶金机理,应用冶金热力学、动力学和传输理论,建立描述转炉脱碳过程的动力学模型,确定了模型的有关参数.模型的关键在于正确计算并比较钢液中[C]和[O]的传质速度,找到转炉冶炼脱碳过程的限制环节,并通过一系列热力学计算得到进入钢液的氧在各元素间的分配比例,从而得到转炉中脱碳反应的速度方程.将模型应用于本钢150 t转炉冶炼过程,模型在不同时刻的计算结果与现场实测值吻合较好.     

Numerical modelling of iron flow and heat transfer in blast furnace hearth

Abstract

The erosion of hearth refractories is widely recognised as the main limitation for a long campaign blast furnace life. Distributions of liquid iron flow and refractory temperatures have a significant influence on hearth wear. In this investigation, a comprehensive computational fluid dynamics model is described which predicts the fluid flow and heat transfer in the hearth; specifically, the flow and temperature distributions in the liquid iron melt, and temperature distributions in the refractories. The accuracy and representativeness of the model was evaluated using plant data from BHP Steel's Port Kembla no. 5 blast furnace and OneSteel's Whyalla no. 2 blast furnace. Generally, there is good agreement between measured and calculated refractory temperature profiles. A series of sensitivity tests provided cause-effect relationships between operational and fluid flow parameters (floating deadman, different extent of refractory erosion, presence of embrittled layer).     

首钢京唐公司脱磷转炉半钢无氟化冶炼实践

针对首钢京唐公司脱磷转炉半钢冶炼渣系组分单一、化渣困难、使用萤石造渣时对炉衬侵蚀严重等问题,应用无氟化造渣新工艺进行脱磷半钢冶炼,结果表明:新工艺的使用保证了半钢炼钢化渣效果,改善了终渣流动性,保证了去磷效果,能够取代萤石进行造渣,节约生产成本。     

硅还原转炉熔渣气化脱磷热力学分析

以离子理论为基础,从转炉渣脱磷热力学分析人手,计算确定了气化脱磷反应的最终产物,对转炉溅渣护炉过程中气化脱磷的热力学可行性提供了理论依据.结果表明,在转炉内还原炉渣气化脱磷是可行的.并讨论了温度、碱度、FeO含量、流动氮气等因素对炉渣气化脱磷产物平衡分压的影响.     

Dynamic modelling of an industrial copper solvent extraction process

The dynamic behaviour of an industrial copper solvent extraction mixer–settler cascade is modelled to develop an advanced process control system. First, the process is introduced and the dynamical models are formulated. The testing environment is described and the successful results presented. Only industrially measured variables are required and plant-specific McCabe-Thiele diagrams are utilized to predict copper concentrations. The results with constant and adapted parameters are compared and the importance of parameter adaptation is discussed. Testing the simulator with adapted parameters over a period of 1 month of industrial operating data gave data that followed the real process measurements closely. In the future, the mechanistic models will be used for control system development and testing. The model can be used on all copper solvent extraction plants by modifying the flow configuration and adapting parameters.     

Improvement of reaction efficiency in hot metal dephosphorisation

Abstract

In Japan, the hot metal pretreatment process has been developed to refine hot metal under conditions where each impurity can be removed most efficiently. At Nippon Steel, three types of hot metal pretreatment process, using torpedo car, hot metal ladle, or LD converter, are employed, that make a great contribution to the reduction of slag volume. Recently, Nippon Steel has developed a new hot metal pretreatment called the multirefining converter (MURC) process, in which dephosphorisation and decarburisation are carried out continuously in the same converter. Nevertheless, since the dephosphorisation efficiency of CaO is less than 30%, CaO is now being used in far greater quantities than that stoichiometrically required to make 3CaO.P₂O₅. As hot metal dephosphorisation is a non-equilibrium reaction, in which hot metal is in contact with slag whose oxygen activity differs greatly from that of hot metal, it is important to increase the interfacial oxygen activity. From the results of a fundamental experiment, the 2CaO.SiO solid phase, in which P₂O₅ can be dissolved, has a great effect on the dephosphorisation reaction.     

应用改进的神经网络模型预报转炉冶炼终点

准确预报转炉冶炼终点的钢水温度与碳含量对提高转炉终点命中率具有重要意义。针对现有多层前馈网络学习算法的不足,基于BP模型提出一种改进算法,建立了复吹转炉冶炼终点的预报模型,并与BP模型的预测结果进行了统计比较。研究表明,改进后的模型能够对冶炼终点进行良好的预报。采用单节点输出模型对终点钢水碳含量与温度分别进行预报,预测误差w(Δ[C])<±0.03%的命中率达97.22%,Δt<±12℃的命中率为94.44%。还建立了神经网络双节点输出模型对转炉终点钢水碳含量及温度同时进行预报,误差Δt<±15℃、w(Δ[C])<0.03%的双命中率为76.92%。