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.     

转炉炉气分析技术在本钢的初步应用

结合本钢炉气分析在线系统,建立了应用物料平衡原理预测碳含量及根据反应平衡原理预测温度变化的转炉动态模型.模型预测结果表明:熔池中的碳含量是炉气流量及CO和CO2分压的函数,其中初始碳含量的准确程度对模型的最终预测结果影响最大.熔池温度是碳含量及炉气中CO和CO2分压的函数,其中吹炼过程的平稳性是模型最终预测结果准确获得的保证.并应用本模型对1 530炉次的历史炉气数据进行了离线分析与终点检测结果的比较,收到预期效果.     

基于转炉烟气分析的熔池碳含量及温度动态预报

基于烟气分析获得烟气流量及成分,应用碳平衡原理构建的碳积分数学模型可动态预测熔池中的碳含量;对炉气信息延迟性、炉气量、枪位系数和脱碳速率拐点a与b等参数的修正,能够提高熔池碳含量动态预报的精度。在熔池碳含量动态预报的基础上,基于热平衡理论和碳氧反应热力学构建了熔池温度动态预报模型,通过脱碳速率拐点a和b的修正以及分阶段模型的构建,能够提高熔池温度的预报精度。在此基础上采用Visual Basic 6.0和SQL Server 2000数据库构建了熔池碳含量和温度动态预报系统,利用该系统对一定时期的46炉冶炼数据进行了离线运行,结果表明:终点w(C)0.2%时,预报偏差小于0.02%命中率为84.8%,模型终点温度预报偏差小于20℃命中率为84.8%,C-T双命中率达到73.9%,基本满足冶炼对终点命中率的要求。     

基于炉气分析熔池碳含量的在线测量

采用飞行质谱技术构造的炉气分析系统,依据质量平衡原理,结合炉气流量计测得的炉气流量,计算出了熔池的瞬时脱碳速度,采用碳积分模型或者碳曲线拟合模型预测计算熔池中的碳含量,为解决熔池碳含量在线测量分析技术的难题提供参考.     

通过炉气分析实现转炉连续控制

应用红外测试仪测得的炉气数据,根据转炉熔池物料平衡和热平衡,通过模型计算,论证了炉气分析在转炉连续控制中对碳和温度预报的可行性,并得出结论;炉气分析对终点戳w(C)≤0.06%炉次的碳预报命中率较高,适用于低碳钢冶炼.但该模型进行温度预报的数据来源均为间接数据,命中率较低.     

氧气顶吹转炉吹炼过程动态模型

通过炉气流量和成分的在线采样信息，用积分法计算熔池排出碳量，并根据熔炼体系中碳的守恒，动态推算熔池含碳量，由此来预报吹炼终点。较深入研究了提高炉气流量检测精度的方法，如心平衡修正和钢液成分反馈修正等，并采用了滤波算法，这些措施有利于提高动态模型的精度。     

炉气分析技术在转炉熔池温度研究中的应用

通过对转炉内外二次燃烧率的分析,结合质量平衡和反应平衡理论,对熔池中碳和温度的变化进行了实验并与模型计算结果相比较,得出结论是：①在做好废钢和炉气密封工作的前提下,应用质量平衡可实现对熔池中碳的准确预测;②转炉内外的二次燃烧率均呈吹炼前期高、中期低、后期再次升高的变化趋势;③利用反应平衡理论可对吹炼中后期的熔池温度进行预测。     

转炉炼钢熔池碳含量动态变化研究

通过引入炉气分析仪采集的实测数据,用碳指数模型描绘熔池内碳含量实时变化趋势,并用修正后的碳积分模型计算转炉吹炼过程的总脱碳量,以对碳含量的动态变化和终点出钢情况做出预报.在机理分析的基础上,利用三阶段脱碳曲线的后期变化趋势建立碳指数实时和终点预报模型,同时对碳积分计算公式加以修正,得到冶炼全程的脱碳率计算模型.仿真结果表明,碳指数及碳积分模型直接用于指导转炉炼钢生产具有一定的参考价值,在一定程度上可以取代炉气分析仪的使用.     

基于熔池混匀度的转炉烟气分析定碳模型

转炉冶炼终点碳曲线拟合模型避开了熔池初始碳含量难以精准确定的问题,假设吹炼后期脱碳速率与熔池碳含量具有一定的函数关系,通过这种函数关系预报钢水终点碳含量.终点碳的三次方模型和指数模型预报精度在±0.02%之间的命中率分别为85.9%和81.2%.运用熔渣分子理论,基于冶炼热轧板材(SPHC)的渣组元成分,计算得出渣中FeO的活度为0.241.出钢温度为1686℃时,C和Fe元素选择性氧化的临界碳质量分数为0.033%.本文在传统指数模型的基础上,充分考虑了枪位、顶吹流量、底吹流量等操作参数对熔池脱碳速率的影响,建立了基于熔池混匀度的指数模型.基于熔池混匀度的指数模型与其他烟气分析碳曲线拟合模型相比,命中率有所提高.以新钢生产热轧板材(目标碳质量分数为0.06%)时的烟气数据为研究对象建模,终点碳质量分数预报误差在±0.02%之间的有75炉次,占验证数据量的88.2%.      

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.     

铁碳熔池中废钢熔化行为的研究进展

在钢铁冶金过程中,逐步减少铁矿石比例、增加废钢比例,实现钢铁循环,已成为世界钢铁行业追求的目标.废钢的熔化行为是控制转炉炼钢过程温度轨迹和废钢比以及电弧炉炼钢能耗和产能的关键因素;同时,铁水包中废钢的熔化行为可能影响铁水预处理工艺的顺利进行.研究废钢的熔化行为对提高废钢在转炉、电弧炉和铁水包等设备中的利用率以及对保证钢...     

MTA废气分析在VOD脱碳过程中的应用

为了实现对VOD脱碳终点碳含量进行动态控制,以某钢厂120 t VOD炉冶炼不锈钢的脱碳过程为研究对象,通过MTA（multi task analyzer）废气分析系统分析VOD精炼中CO、CO2等废气成分随时间变化的规律。同时以物质碳平衡为基础,建立了基于废气分析的VOD冶炼碳终点控制的模型,对精炼过程中钢水碳变化情况进行分析。通过对实际值和预测值之间的偏差进行考察,说明了模型能够较好地预测碳含量的总体发展趋势。模型计算VOD脱碳终点碳质量分数误差都在±0.03%之内,模型计算值与实际测量值具有一定的吻合性。     

超纯铁素体不锈钢VOD脱碳模型研究

摘要：为了实现对超纯铁素体不锈钢VOD精炼脱碳过程的动态即时预测及控制,以酒钢宏兴不锈钢分公司100 t VOD炉冶炼超纯铁素体不锈钢的过程为研究对象,从顶吹氧气的分配行为和C Cr的竞争氧化出发,建立基于炉气分析技术的VOD动态脱碳模型,并在Matlab环境下开发相应的应用软件,得到全过程钢液成分、氧气分配比、温度等参数随时间的变化规律,对不同阶段的临界碳浓度给出估计范围。利用VOD出站成分以及精炼过程中CO/CO2的实际变化规律加以检验,与实际值吻合较好,较好地预测了实际变化趋势。     

Oxidation of molten impurities in converters by means of combustion flames: Thermodynamic principles. 2. Interaction of flame with metal and slag in converter bath

Thermodynamic analysis is applied to the physicochemical processes in the converter bath when intensifying bath heating by means of gas–oxygen burners. In the converter’s working space, when the combustion flames interact with the liquid bath, the oxygen and natural gas supplied through the burners and the oxygen supplied through the tuyere interact in a bubbling slag–metal emulsion. As a result, iron and the impurities are oxidized. The use of such burners changes the gas composition: not only O₂, CO, and CO₂ are present, but also H₂ and H₂O, which changes the oxidative capacity of the gas phase. The presence of solid carbon (for example, pulverized coal) in the burner flame may be used to control and intensify the combustion process. Combustion is most effective in the oxidation of carbon to CO when the oxygen excess is less than 1.0. The oxidation conditions of carbon in the melt change with variation in its activity as a function of its concentration and the temperature. The equilibrium in the M–O–C system may be described by the oxygen partial pressure \({P_{{O_2}}}\), which may be regarded as a universal characteristic. In addition, the equilibrium may be assessed on the basis of the associated ratios \({P_{CO}}/{P_{C{O_2}}}\) and \({P_{{H_2}}}/{P_{{H_2}O}}\) It is found that iron may be oxidized by oxygen and, to some extent, by carbon dioxide. At 1600–2000 K, there is practically no oxidation of iron by steam. The carbon dissolved in the steel is oxidized relatively effectively by oxygen and carbon dioxide until its concentration is less than 0.1% C. Steam oxidizes carbon very poorly and is not much more effective with manganese and silicon. With increase in temperature, the rate at which carbon dissolved in steel is oxidized by oxygen increases, while the oxidation rate of manganese and silicon falls. Above 1800 K, superoxidized slag with a high FeO content actively oxidizes silicon (to <2% Si), manganese (to <1% Mn), and carbon (to <1.5% C).     

Mathematical modeling of the argon-oxygen decarburization refining process of stainless steel: Part I. Mathematical model of the process

Some available mathematical models for the argon-oxygen decarburization (AOD) stainless steelmaking process have been reviewed. The actual situations of the AOD process, including the competitive oxidation of the elements dissolved in the molten steel and the changes in the bath composition, as well as the nonisothermal nature of the process, have been analyzed. A new mathematical model for the AOD refining process of stainless steel has been proposed and developed. The model is based on the assumption that the blown oxygen oxidizes C, Cr, Si, and Mn in the steel and Fe as a matrix, but the FeO formed is also an oxidant of C, Cr, Si, and Mn in the steel. All the possible oxidation-reduction reactions take place simultaneously and reach a combined equilibrium in competition at the liquid/bubble interfaces. It is also assumed that at high carbon levels, the oxidation rates of elements are primarily related to the supplied oxygen rate, and at low carbon levels, the rate of decarburization is mainly determined by the mass transfer of carbon from the molten steel bulk to the reaction interfaces. It is further assumed that the nonreacting oxygen blown into the bath does not accumulate in the liquid steel and will escape from the bath into the exhaust gas. The model performs the rate calculations of the refining process and the mass and heat balances of the system. Also, the effects of the operating factors, including adding the slag materials, crop ends, and scrap, and alloy agents; the nonisothermal conditions; the changes in the amounts of metal and slag during the refining; and other factors have all been taken into account. []—metal phase; ()—slag phase; {}—gaseous phase; and 〈〉—solid phase