电炉回收烟气余热实现负能除尘

淮钢70t电炉随着生产率的大幅提高,除尘系统能力不足,大量高温烟气余热浪费等问题同时也暴露出来,为此,结合设备、工艺特点,采用先进技术,对电炉除尘系统进行了技术改造,既治理了烟尘同时又回收了高温烟气余热,实现了电炉的负能除尘。     

Nitrogen Removal and Arc Voltage Increase in EAF Steelmaking by Methane Injection into the Arc

Methane injection into the arcs of electric arc furnaces has been shown on pilot scale to lead to a remarkable arc voltage increase at constant arc current and arc length. Recent investigations have been concerned with the associated metallurgical effects making use of a gas‐tight 150‐kg arc furnace operated with two AC plasma torches. A first test with bored graphite electrodes in this furnace confirmed the power increase observed during methane injection. The carburization slowly occurring when 6 % CH₄ were injected into the argon atmosphere of the furnace could be avoided by adding minor amounts of CO₂. A slag layer decreased mass transfer rates without noticeably affecting heat transfer. Manganese loss by evaporation was measured to investigate the influence of power increase and slag layers. From the results, an increase of 200 K was concluded for the melt surface temperature when CH₄ was added to pure argon. Methane injection into the arcs proved to accelerate nitrogen removal considerably. Starting with an intentionally high nitrogen content of about 200 ppm, the nitrogen removal rate was found to be slowest with pure argon plasma arcs, faster with 90 % Ar + 10 % H₂, and fastest with 95 % Ar + 5 % CH₄ reaching final contents of less than 20 ppm of nitrogen. Based on thermodynamic calculations, the denitrogenation reactions appear to take place via atomic nitrogen in pure argon plasma, via NH₃ in Ar + H₂ and via HCN in Ar + CH₄.     

高阻抗电弧炉的设计

工程设计应用表明：采用电弧功率恒定法确定电抗器容量及变压器等电气参数；高阻抗可减少电流波动46％，降低了电压闪烁近30％，减少了无功功率补偿容量。     

Fluid Flow and Heat Transfer Modeling of AC Arc in Ferrosilicon Submerged Arc Furnace

 arc has been developed and used to predict heat transfer from the arc to the molten bath in ferrosilicon AC submerged-arc furnace. In this model the time-dependent conservation equations for mass, momentum and energy in the specified domain of plasma zone have been solved numerically coupled with the Maxwell and Laplace equations for magnetic filed and electric potential respectively. A control volume based finite difference method was used to solve the governing equations in cylindrical coordinates. The reliability of the developed model was tested by comparison with the data available in the literature. The present model showed a better consistency with the data given in the literature because of solving the Maxwell and Laplace equations simultaneously for calculation of current density. Parametric studies were carried out to evaluate the effect of electrical current and arc length on flow field and temperature distribution within the arc. According to computed results, a lower power input lead to the higher arc efficiency.     

超高功率电弧炉变压器容量及技术参数的确定

除电弧炉容量外 ,原料、辅助能源、冶炼品种、冶炼工艺和生产流程等生产状况均影响电弧炉变压器额定容量的确定。经分析得出以废钢为原料的超高功率电弧炉变压器额定容量P_n/kVA与吨钢电耗W、变压器功率利用率C₂ 、总通电时间t_on、出钢量G之间的关系式为 :P_n=(W·G·60 )/(t_on·cosφ·C₂ ) ,同时给出了二次电压的确定方法。结合高阻抗技术 ,给出超高功率高阻抗电弧炉电抗容量与变压器技术参数的确定方法以及确定石墨电极二次导体截面积的思路     

我国电弧炉炼钢技术的进展讨论

10年来我国电弧炉炼钢技术在产量、装备技术(大型化、高的技术经济指标)、高效化技术(超高功率供电、辅助能源、炉料多元化、减少非通电时间、废钢预热、连续化生产)和洁净化技术方面均取得了显著进展。但是废钢资源短缺、电力不足和能源结构不合理等因素制约了我国电弧炉炼钢的进一步发展。文中讨论了我国电弧炉炼钢发展的重点(炉料多样化、合理供电、能量多样化、余热利用和绿色环保)和前瞻(低碳经济洁净钢生产)。     

Fluid Flow Modeling of Arc Plasma and Bath Circulation in DC Electric Arc Furnace

 A mathematical model describing the flow field, heat transfer and the electromagnetic phenomenon in a DC electric arc furnace has been developed. First the governing equations in the arc plasma region are solved and the calculated results of heat transfer, current density and shear stresses on the anode surface are used as boundary conditions in a model of molten bath. Then a two dimensional time dependent model is used to describe the flow field and electromagnetic phenomenon in the molten bath. Moreover, the effect of bottom electrode diameter on the circulation of molten bath is studied.     

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。     

电弧炉电弧特性与节电可行性分析

为了最优化修正电弧炉现场操作工艺,达到提高效率,降低电弧炉能耗的目的,分析了电弧炉的电弧特性以及电弧炉节电的可行性。     

现代超高功率电弧炉的技术特征

综述了现代超高功率电弧炉的技术特征和效果。指出目前超高功率电弧炉技术的发展主要体现在高变压器利用率、工艺和流程优化、改善环境等方面。     

直流电弧炉的偏弧现象及其对策

伴随着直流电弧炉的大型化和高功率化，直流电弧出现了偏弧现象，导致炉料熔化不均，热损失增大及重新出现炉壁热点等缺点，限制了大型直流电弧能力的发挥。针对这种情况，本文从理论上分析了直流电弧炉产生偏弧现象的原因，并提出了改善的措施。     

Arc Distribution During the Vacuum Arc Remelting of Ti-6Al-4V

Currently, the temporal distribution of electric arcs across the ingot during vacuum arc remelting (VAR) is not a known or monitored process parameter. Previous studies indicate that the distribution of arcs can be neither diffuse nor axisymmetric about the center of the furnace. Correct accounting for the heat flux, electric current flux, and mass flux into the ingot is critical to achieving realistic solidification models of the VAR process. The National Energy Technology Laboratory has developed an arc position measurement system capable of locating arcs and determining the arc distribution within an industrial VAR furnace. The system is based on noninvasive magnetic field measurements and a VAR specific form of the Biot–Savart law. The system was installed on a coaxial industrial VAR furnace at ATI Albany Operations in Albany, OR. This article reports on the different arc distributions observed during production of Ti-6Al-4V. It is shown that several characteristic arc distribution modes can develop. This behavior is not apparent in the existing signals used to control the furnace, indicating the measurement system is providing new information. It is also shown that the different arc distribution modes observed may impact local solidification times, particularly at the side wall.     

Calculation and Analysis of the Relationship Between the Efficiency and Position of Electric Arcs and Power Consumption in Electric Arc Furnaces (EAF) of Smaller and Larger Capacity. Part I. Calculation and Analysis of the Relationship Between Arc Efficiency and Power Consumption

Metallurgist - The arc efficiency and specific power consumption were calculated and analyzed for the small (1.5 to 20 tons) and large (100 to 120 tons) capacity electric arc furnaces. In the...     

近代电弧炉的容量和输入功率

70 t以上电弧炉已成为当代新建电弧炉厂的主导炉型。电弧炉的输入功率和冶炼周期应根据产品结构、生产炉型和市场需求来确定。     

现代炼钢电炉电气特性与供电制度的设计

在一定设备条件下,供电制度合理与否,不但影响冶炼过程的顺利,还影响炉衬寿命、冶炼周期、电能消耗以及设备利用等。在分析炼钢电炉电气特性的基础上,绘出电炉理论电气特性曲线,介绍二次电压确定原则,并以“经济电流”概念,考虑到诸多相关因素,给出确定合理的供电制度方法。     

电弧炉的谐波治理及其效果

通过装设滤波装置,对注入电网的谐波进行治理,防治电弧炉产生的谐波危害,消除电气设备事故的诱发因素,并对无功功率进行补偿,降低了电耗,提高了质量.     

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.     

70 t电弧炉热兑转炉液态渣的工艺实践

转炉液态渣的碱度(CaO/SiO₂)一般为2.8～4.2,热容2.5 kJ/(kg·℃),进入渣罐后的炉渣温度约为1 540℃,有良好的导电性,可以利用其热能和氧化钙。当70 t电弧炉兑加120 t转炉液态渣8 t,可使平均冶炼周期由52 min降至47 min,电耗由400 kWh/t降至355 kWh/t,石灰加入量由3.6 t降至1.0 t,氧气消耗由28 m~3/t降至25 m~3/t,可有效地节约资源和减少炉渣的排放。     

Electric Melting of Iron-Ore Prereduced Pellets in an Electric Arc Furnace

This article discusses the aspects of the melting loss in electric steelmaking during continuous feeding of prereduced pellets into the bath of an electric arc furnace via hollow electrodes. It is shown that adjustment of the melting loss and the dust discharge from electric arcs by changing the pellet consumption and accounting for the heat parameters of furnace operation makes it possible to significantly increase the ingot-to-product yield during electric steelmaking.     

Analysis of the state of structure and the basic parameters and indices of the operation of the large EAFs operating in the metallurgical plants in Russia

16 mln t steel were melted in 24 large electric arc furnaces (EAFs) in the metallurgical plants in Russia furnaces in 2011 at an annual capacity of 22 mln t of these furnaces. Among them, 17 EAFs are equipped with eccentric bottom tapping and operate with a “bog.” Three EAFs use the heat of effluent gases for heating of a charged scrap: a shaft heater at the Cherepovets metallurgical works (CherMK) and conveyer heating in the Ashinsk metallurgical plant. The DSP-120 furnace in CherMK has the best indices in Russia for operation with cast iron: electric power consumption of 260 kWh/t and a heat time of 49 min. Nine EAFs operating in metallurgical works use 20–30% liquid iron in a charge, which decreases the electric power consumption by 80–100 kWh/t. The working space and the EAF dimensions are important. A groundless decrease in the electrode failure diameter (1200 mm or smaller) leads to problems in the EAF transformer operation at a transformer power higher than 100 MVA and a secondary voltage higher than 1000 V. The performance of EAFs and the reliability of equipment operation depend on the working space height, the electric holder stroke, the distance between the axes of chair segments, the distance from the furnace axis to the axis of electric holder supports, and so on. Engineers in OOO NTP Akont determined the optimum sizes and relations between them for 120- to 130-t EAFs.