Thermal operation of the DSP-120 Consteel furnace in the Ashinsk metallurgical works

The heat losses with waste gases in modern electric arc furnaces are 20–25%. Scrap heating by waste gases is performed in Fuchs Systemtechnik shaft furnaces and Consteel furnaces with conveyer charging. The results of balance heats conducted in the DSP-120 Consteel electric furnace located in the Ashinsk metallurgical works are presented, and measures for increasing the energy efficiency of its operation are proposed.     

Effect of the geometric parameters of the EAF bath on the main characteristics of furnace operation

The models of melting a semiproduct in an electric arc furnace (EAF) and metal mixing developed earlier are used to study the effect of the proportion of the bath sizes on the following main technicaleconomic characteristics of a heat: the expenditure of electric energy, the heat time, and the operating time under electric current. The range of the optimal values of the proportion of the EAF bath sizes is determined with allowance for bath stirring with CO bubbles during decarburization. It is useful to increase the bath depth of EAFs operating according to single-slag technology and to classify furnaces according to the type of charge and the method of its loading.     

40 t电弧炉高效化生产实践

兴澄特钢3座40 t电弧炉(变压器容量每座15MVA)经过氧枪等改造和添加铁水等工艺措施优化后,使每炉冶炼时间由3 h降至60～70 min,电耗降至160 kWh/t,氧耗为50 m³/t,电极消耗2.0 kg/t,3座电弧炉年产能力达85万t。操作实践表明,每炉20～25 t的铁水加入量可使40 t电弧炉得到最佳的经济指标。     

电弧炉炼钢提高生产率的技术进展

近几年来,电弧炉炼钢生产率有较大的提高。提高电弧炉炼钢生产率主要基于以下几项新技术,包括改善电弧炉电效率、强化供氧技术、智能控制技术（专家系统）等。对国内外几座先进的电弧炉技术经济指标进行了比较。提高电弧炉生产率是今后电弧炉炼钢的发展方向。     

New algorithm for controlling electric arc furnaces using their vibrational and acoustic characteristics

The processes occurring in arc discharges are analyzed as the sources of acoustic radiation in an electric arc furnace (EAF). Acoustic vibrations are shown to transform into mechanical vibrations in the furnace laboratory. The shielding of the acoustic energy fluxes onto water-cooled wall panels by a charge is experimentally studied. It is shown that the rate of charge melting and the depth of submergence of arc discharges in the slag and metal melt can be monitored by measuring the vibrational characteristics of furnaces and using them in a universal industrial process-control system, which was developed for EAFs.     

Acoustic characteristics of electric arc furnaces

A mathematical model is constructed to describe the appearance and development of the noise characteristics of superpower electric arc furnaces. The noise formation is shown to be related to the pulsation of the axial plasma flows in arc discharges because of the electrodynamic pressure oscillations caused by the interaction of the self-magnetic field with the current passing in an arc. The pressure in the arc axis changes at a frequency of 100 Hz at the maximum operating pressure of 66 kPa for an arc current of 80 kA. The main ac arc sound frequencies are multiples of 100 Hz, which is supported in the practice of operation of electric arc furnaces. The sound intensity in the furnace laboratory reaches 160 dB and is decreased to 115–120 dB in the working furnace area due to shielding by the furnace jacket, the molten metal, and the molten slag. The appropriateness of increasing the hermetic sealing of electric furnaces and creating furnaces operating at low currents and high transformer voltages is corroborated.     

120 t LF供电曲线的优化

LF(钢包炉)二次精炼是邯钢转炉-LF-CSP流程生产冷轧低碳钢的关键工序。通过所建立的优化模型,研究了20 MW、120 t LF的电气特性,以优化供电曲线和缩短精炼时间、提高精炼效果。结果表明,邯钢LF不同档位下最快升温速度为1.45～5.14℃/min;通过合理工作点,在第3档电压(302 V)下,可将升温速度从目前的4.01℃/min提高到4.58℃/min。     

20t电弧炉冶炼工艺优化

针对莱钢特钢厂20t电弧炉冶炼过程中存在的挂料现象、冶炼周期长、电耗高、氧气利用率低、炉衬渣线侵蚀严重、炉衬寿命低等问题,采取了优化入炉废钢结构、铁水热装、优化供电制度、泡沫渣埋弧操作、炉门氧枪供氧技术、油氧助熔技术和炉衬喷补等技术,使20t电弧炉冶炼周期缩短26min,变压器利用系数提高41.51%,炉体寿命提高286炉次,保证了连铸的顺行。     

直流电弧炉用镁碳质耐火材料的研究

直流电弧炉有利于提高钢质量和减少闪变（电网干扰）故它的应用正在推广，与交流电弧炉相比，安的电极安装在炉子底部，电极的寿命和安全很重要，本文阐述了直流电弧炉用镁碳质耐火材料的研究及发展。     

国外电弧炉炼钢的最新进展

介绍了国外电弧炉炼钢的最新进展,对比了正被使用和将被采用的不同炉型如单级和双级的ＡＣ与ＤＣ电弧炉以及连续作业的电弧炉,并对其冶金原料,生产工艺、节能、电极材料消耗和自动化控制程度等进行了介绍。随着环保霜求的日益严格,电弧炉烟尘的治理也越来越受到重视。     

铸钢用50 t/32 MVA交流电弧炉炼钢过程电气运行特性

使用电气监测仪表对中信重工机械股份有限公司50t/32 MVA交流电弧炉炼钢过程中的电气参数进行了实测,得到52 310个有效数据。结果表明,有载条件下电抗器上端的功率因数均为0.800以上,供电回路中的电压、电流以及功率因数均处于三相平衡状态。以二次侧工作电流为自变量,建立非线性电抗模型,绘制电气运行特性曲线,确定现用各挡电压下的工作电流许用范围。研究表明,若将电抗器挡位由原来的3挡改设为4挡运行,则炉用变压器容量利用率将提高7.30%,功率因数将由原来的0.812提高为0.841。     

安钢100 t交流竖式电弧炉控制冶炼周期的工艺实践

安阳钢铁公司100 t交流竖式电弧炉于1999年11月投产,其变压器容量为60~72 MVA。冶炼时兑33%左右的铁水,竖炉预热废钢的温度达400~600℃,并采用氧油烧嘴和水冷碳氧枪操作和圆心炉底出钢(出钢量110 t)等操作技术使电弧炉电耗降至220 kWh/t,电弧炉作业率达92%,冶炼周期平均为41 min,年产钢量超过100万t,显著降低了生产成本。     

Thermal physics as the basis for energy and resource conservation in steelmaking

This article outlines improvements in metallurgical technology achieved on the basis of the integration of thermal physics and information science by the Ural school of specialists in metallurgy and thermal physics. In recent years, mathematical modeling, combined with physical modeling, has significantly reduced the optimization time in the thermal design and debugging of new technologies and equipment. Sintering machines have been modernized by introducing automatic control of the thermal and gas-dynamic processes and by designing new ignition hearths. These measures, besides improving heat and mass transfer, have boosted the performance of sintering plants in Russia and elsewhere, while reducing their environmental impact. In pellet roasting, a refined gas-flow system has been organized, and the gas lines have been reconstructed. As a result, the productivity has increased by 10–17%, with 8–15% decrease in the fuel consumption. The losses of gas after purification have fallen by 50–58%. Roasting machines in Russia, Brazil, and Iran have been reconstructed. In recent years, software has been developed for blast furnaces and introduced at Russia’s largest steelworks: OAO Magnitogorskii Metallurgicheskii Kombinat. In blast furnaces, new air heaters for the blast produce temperatures of 1300°C or more by means of furnace gas and air, without added natural gas. In addition, systems processing metallurgical liquid slag at rates of 3–15 t/min and producing granulated slag at a rate of 0.66–2.0 million t/yr have been built at Russian, Ukrainian, Indian, and Chinese steel plants. A system is also operating successfully at the Norilsk Nickel plant. The thermal conditions in heating furnaces and equipment of various types have been improved on the basis of mathematical simulation of thermophysical processes by means of a dynamic zonal–point model of radiant and complex heat transfer. This method performs well in practice. In recent years, new furnace designs have been developed, and hundreds of heating furnaces have been modernized. Optimal thermal organization has significantly reduced fuel consumption, improved heating of the metal, and resulted in higher quality of the heat-treated product.     

Control of greenhouse gas emissions from electric arc furnace steelmaking: evaluation methodology with case studies

Abstract

The energy intensive nature of electric arc furnace (EAF) steelmaking necessitates that efforts to reduce greenhouse gas (GHG) emissions will affect steelmakers directly and/or through electric power producers. A model of GHG emissions from an EAF meltshop has been developed using the life cycle assessment approach. Direct and indirect sources of GHG gas emissions are estimated and ranked. Furnace combustion optimisation was evaluated in case studies conducted on a Canadian conventional EAF and a British scrap preheating `shaft' furnace. The analysis assumed 32 and 68% fossil fuel electricity generation, respectively. These case studies show that indirect GHG emission sources, in particular electricity generation, are more significant than direct emissions from the EAF. For the conventional EAF, offgas analysis and improved combustion control reduced electricity consumption by 40 kWh t^-1, costs by US$1·05/t, and GHG emissions by 20 kg CO₂-eq./t. For the shaft EAF, real time offgas monitoring and closed loop burner control reduced electricity consumption by 25 kWh t^-1, costs by US$3·6/t, and GHG emissions by 15 kg CO₂-eq./t. The case studies show that combustion optimisation using an EAF offgas analysis and combustion control system provides greater electricity, cost, and GHG reductions than previously reported in the literature.     

100t 电弧炉 Cojet集束氧枪的应用

安阳钢铁公司100 t电弧炉在复产改造中采用炉壁Cojet集束氧枪替代原有的炉壁氧燃烧嘴。100 t电弧炉改造复产后,炉料为80 t废钢+30 t生铁时,EAF冶炼周期55 min,电耗360 kWh/t,电极消耗1.6 kg/t;当炉料为60%废钢+40%铁水时,EAF冶炼周期50 min,电耗225 kWh/t,电极消耗1.2 kg/t,实现电弧炉低成本高效化运行。     

Shift From Coke to Coal Using Direct Reduction Method and Challenges

 Ironmaking involves the separation of iron ores. It not only represents the first step in steelmaking but also is the most capital intensive and energy intensive process in the production of steel. The main route for producing iron for steelmaking is to use the blast furnace, which uses metallurgical coke as the reductant. Concerns over the limited resources, the high cost of coking coals, and the environmental impacts of coking and sinter plants have driven steelmakers to develop alternative ironmaking processes that can use non coking coals to reduce iron ores directly. Since the efficiency and productivity of modern large capacity blast furnaces will be difficult to surpass, blast furnaces will continue to retain their predominant position as the foremost ironmaking process for some time to come. The alternative ironmaking processes are therefore expected to play an increasingly significant role in the iron and steel industry, especially in meeting the needs of small sized local and regional markets. It is likely that the importance of direct reduced iron (DRI) and hot metal as sources of virgin iron will continue to increase, especially in the developing countries where steelmaking is, and will be, primarily based on electric arc furnace (EAF) minimills. Consequently, the challenges that are faced by the new technology have to be embraced.     

Simulation of the mass and heat transfer in a three-electrode round impoverishment furnace

A thermophysical model is developed for a three-electrode round impoverishment furnace operating with electrodes immersed in a slag melt in order to predict the operation of the impoverishment furnaces located at the Nadezhdinsk metallurgical works of the Noril’sk Nikel integrated works and to optimize their energy-technical conditions. This model provides reliable information on the temperature field in the slag bath of a furnace depending on the furnace operating schedule, the velocity and character of motion of a slag melt, the heat release in different regions of the slag melt, and (hence) the heat load applied to furnace elements. The results of calculation by this model were used to make recommendations for improving the designs of the furnaces operating at the Noril’sk Nikel integrated works and for changing their operating conditions.     

电炉煤氧喷吹的技术改造及工艺改进

简要介绍了国内第一套电炉煤氧喷吹强化电炉冶炼生产线的设备改造及工艺改进情况，使唐钢电炉钢冶炼电耗实现了“破五进四”的奋斗目标，达到４８４ｋｗｈ／ｔ的同类炉型国内先进水平，取得了较好的经济效益。     

面向21世纪的冶金技术——DC电弧炉炼钢

阐述了直流电弧炉的发展与现状，以及其设备及工艺特点，并与交流电弧炉进行了比较。认为直流电弧炉有取代交汉电弧炉的趋势，从冶金技术的发展方向看，直流电弧炉炼钢将是面向二十一世纪的冶金技术。     

用于制备氮化硅粉的高温电阻炉的设计与应用

设计了三种不同加热方式的高温电阻炉，即外壁加热、内芯加热和双重加热高温炉。介绍了电热元件的材料选取、尺寸确定，保温材料的选用，热电偶的选择与安装。分析了三种高温炉的耗电量、散热量和使用寿命。通过对比。内芯加热高温炉耗电量最低、使用寿命最长，双重加热高温炉升温速度最快，外壁加热高温炉的炉膛有效面积最大。