Electric Arc Furnace Voltage Flicker Mitigation by Applying a Predictive Method with Closed Loop Control of the TCR/FC Compensator

Kiyoumarsi, Arash,Ataei, Mohhamad,Hooshmand, Rahmat-Allah,Kolagar, Arash Dehestani The Korean Institute of Electrical Engineers 2010 Journal of Electrical Engineering & Technology Vol.5 No.1

Modeling of the three phase electric arc furnace and its voltage flicker mitigation are the purposes of this paper. For modeling of the electric arc furnace, at first, the arc is modeled by using current-voltage characteristic of a real arc. Then, the arc random characteristic has been taken into account by modulating the ac voltage via a band limited white noise. The electric arc furnace compensation with static VAr compensator, Thyristor Controlled Reactor combined with a Fixed Capacitor bank (TCR/FC), is discussed for closed loop control of the compensator. Instantaneous flicker sensation curves, before and after accomplishing compensation, are measured based on IEC standard. A new method for controlling TCR/FC compensator is proposed. This method is based on applying a predictive approach with closed loop control of the TCR/FC. In this method, by using the previous samples of the load reactive power, the future values of the load reactive power are predicted in order to consider the time delay in the compensator control. Also, in closed loop control, two different approaches are considered. The former is based on voltage regulation at the point of common coupling (PCC) and the later is based on enhancement of power factor at PCC. Finally, in order to show the effectiveness of the proposed methodology, the simulation results are provided.

Electric Arc Furnace Voltage Flicker Mitigation by Applying a Predictive Method with Closed Loop Control of the TCR/FC Compensator

Arash Kiyoumarsi,Mohhamad Ataei,Rahmatollah Hooshmand,Arash Dehestani Kolagar 대한전기학회 2010 Journal of Electrical Engineering & Technology Vol.5 No.1

Modeling of the three phase electric arc furnace and its voltage flicker mitigation are the purposes of this paper. For modeling of the electric arc furnace, at first, the arc is modeled by using current-voltage characteristic of a real arc. Then, the arc random characteristic has been taken into account by modulating the ac voltage via a band limited white noise. The electric arc furnace compensation with static VAr compensator, Thyristor Controlled Reactor combined with a Fixed Capacitor bank (TCR/FC), is discussed for closed loop control of the compensator. Instantaneous flicker sensation curves, before and after accomplishing compensation, are measured based on IEC standard. A new method for controlling TCR/FC compensator is proposed. This method is based on applying a predictive approach with closed loop control of the TCR/FC. In this method, by using the previous samples of the load reactive power, the future values of the load reactive power are predicted in order to consider the time delay in the compensator control. Also, in closed loop control, two different approaches are considered. The former is based on voltage regulation at the point of common coupling (PCC) and the later is based on enhancement of power factor at PCC. Finally, in order to show the effectiveness of the proposed methodology, the simulation results are provided.

Electric Arc Furnace (EAF) Steel Slag의 아스팔트 포장 혼합물 내 대체 골재로서 적용 가능성에 대한 고찰

문기훈 한국도로학회 2015 한국도로학회논문집 Vol.17 No.1

PURPOSES: This paper, presents the results of a laboratory study aimed to verify the suitability of a particular type of Electric Arc Furnace (EAF) steel slag to be recycled in the lithic skeleton of both dense graded and porous asphalt mixtures for flexible pavements. METHODS : Cyclic creep and stiffness modulus tests were performed to evaluate the mechanical performance of three different asphalt mixtures (dense graded, porous asphalt, and stone mastic) prepared with two types of EAF steel slag. For comparison purposes, the same three mixtures were also designed with conventional aggregates (basalt and limestone). RESULTS : All the asphalt mixtures prepared with EAF steel slag satisfied the current requirements of the European standards, which support EAF steel slag as a suitable material for flexible pavement construction. CONCLUSIONS : Based on the experimental work, the use of waste material obtained from steel production (e.g. EAF steel slag) as an alternative in the lithic skeleton of asphalt mixtures can be a satisfactory and reasonable choice that fulfills the “Zero Waste”objective that many iron and steel industries have pursued in the past decades.

Remarks on the use of Electric Arc Furnace (EAF) Steel Slag in Asphalt Mixtures for Flexible Pavements

Augusto Cannone Falchetto,문기훈 한국도로학회 2015 한국도로학회논문집 Vol.17 No.1

PURPOSES: This paper, presents the results of a laboratory study aimed to verify the suitability of a particular type of Electric Arc Furnace (EAF) steel slag to be recycled in the lithic skeleton of both dense graded and porous asphalt mixtures for flexible pavements. METHODS : Cyclic creep and stiffness modulus tests were performed to evaluate the mechanical performance of three different asphalt mixtures (dense graded, porous asphalt, and stone mastic) prepared with two types of EAF steel slag. For comparison purposes, the same three mixtures were also designed with conventional aggregates (basalt and limestone). RESULTS : All the asphalt mixtures prepared with EAF steel slag satisfied the current requirements of the European standards, which support EAF steel slag as a suitable material for flexible pavement construction. CONCLUSIONS : Based on the experimental work, the use of waste material obtained from steel production (e.g. EAF steel slag) as an alternative in the lithic skeleton of asphalt mixtures can be a satisfactory and reasonable choice that fulfills the “Zero Waste”objective that many iron and steel industries have pursued in the past decades.

Thermochemical analysis for the reduction behavior of FeO in EAF slag <i>via</i> Aluminothermic Smelting Reduction (ASR) process: Part II. Effect of aluminum dross and lime fluxing on Fe and Mn recovery

Heo, Jung Ho,Park, Joo Hyun Elsevier 2017 CALPHAD, computer coupling of phase diagrams and t Vol.58 No.-

<P><B>Abstract</B></P> <P>We investigated Fe recovery from EAF slag by means of aluminothermic smelting reduction (ASR) at 1773K with Al dross as the reductant, especially the effect of the added amount of the fluxing agent CaO on the Fe recovery. The maximum reaction temperature calculated using FactSage™ 7.0 decreased with increasing CaO addition, but the experimentally measured maximum temperatures increased with increasing CaO addition. We calculated the amounts of various phases before and after Al dross addition under different conditions of added CaO. FeO and Al<SUB>2</SUB>O<SUB>3</SUB> contents in molten slag sharply varied within the first 5min of the reaction, stabilizing soon thereafter. The aluminothermic reduction of FeO appeared to proceed rapidly and in good stoichiometric balance, based upon the mass balance between the consumption of FeO and MnO (ΔFeO and ΔMnO) and the production of Al<SUB>2</SUB>O<SUB>3</SUB> (∆Al<SUB>2</SUB>O<SUB>3</SUB>). Iron recovery from EAF slag was maximized at about 90% when 40g of CaO was added to 100g slag. Furthermore, Mn could also be reduced from the EAF slags by the metallic Al in the Al dross reductant. The solid compounds of spinel (MgO∙Al<SUB>2</SUB>O<SUB>3</SUB>) and MgO were precipitated from the slag during the FeO reduction reaction, as confirmed by means of XRD analysis and thermochemical computations. To maximize Fe recovery from EAF slag, it is crucial to control the slag composition, namely to ensure high fluidity by suppressing the formation of solid compounds.</P>

Thermochemical analysis for the reduction behavior of FeO in EAF slag <i>via</i> Aluminothermic Smelting Reduction (ASR) process: Part Ι. Effect of aluminum on Fe & Mn recovery

Heo, Jung Ho,Park, Joo Hyun Elsevier 2017 CALPHAD, computer coupling of phase diagrams and t Vol.58 No.-

<P><B>Abstract</B></P> <P>We investigated Fe recovery from EAF slag by means of Aluminothermic Smelting Reduction (ASR) at 1773K, especially the quantitative effect of initial Al/FeO molar ratio upon the Fe recovery. Both calculated and experimentally measured system temperatures continuously increased with increasing initial Al/FeO molar ratio. Furthermore, to predict the reduction behavior we calculated variations in the slag composition by using FactSage™ 7.0 software. FeO and Al<SUB>2</SUB>O<SUB>3</SUB> contents in molten slag varied sharply within the first 5min of the reaction and stabilized soon thereafter. The aluminothermic reduction of FeO appeared to proceed rapidly and in good stoichiometric balance, based upon the mass balance between the consumption of FeO and MnO (ΔFeO and ΔMnO) and the production of Al<SUB>2</SUB>O<SUB>3</SUB> (∆Al<SUB>2</SUB>O<SUB>3</SUB>). Adding an optimal amount of Al (Al/FeO molar ratio ~ 0.8) yielded a Fe recovery of about 90%. Furthermore, the Mn could also be reduced from the EAF slag in the case of excess Al addition (Al/FeO≥0.8). The solid compound spinel (MgO·Al<SUB>2</SUB>O<SUB>3</SUB>) was precipitated from the slag during the FeO reduction, as confirmed by means of XRD analysis and thermochemical computations. Herein, the mechanism of ASR reaction between FeO in molten slag and Al is explained in several steps.</P>

전기로 조업에서 slag gate 영상을 이용한 슬래그 포밍 두께 추정

정재진,김규환,구교권,김상우 제어로봇시스템학회 2014 제어로봇시스템학회 국내학술대회 논문집 Vol.2014 No.5

기체 주입 시스템에서 기-액 상호작용에 관한 연구

서동표,황세준,오율권 朝鮮大學校 機械技術硏究所 2001 機械技術硏究 Vol.4 No.1

Gas-injected system can be applied to various field such as metallurgical and chemical processing operations. So this study aims at presenting the relevant relationship between gas phase and liquid phase in gas-injected bath. The volume fraction, velocity, and temperature distribution of each phase were measured in order to predict the flow characteristics in gas-injected system. The gas discharged into the liquid bath loses its kinetic energy in a short distance from the nozzle exit, and then rises with a relatively uniform velocity due to buoyancy. As the gas rises upward in the liquid, the liquid entrains into the rising gas and a gas-liquid two-phase plume forms. In vertical injection systems, the gas-liquid plume is symmetric about the axis of the injection nozzle. In the region close to the orifice exit, the flow variables show steep spatial changes in both directions along the plume and across the plume. This region can be charaterized as a developing flow region.