Improving the efficiency of electric arc furnaces through improved control algorithms for electrical modes

2020 ◽  
pp. 10-16
Author(s):  
A. A. Nikolaev ◽  
◽  
G. P. Kornilov ◽  
P. G. Tulupov ◽  
G. V. Nikiforov ◽  
...  
Keyword(s):  
Short Circuit ◽  
Unit Cost ◽  
High Energy ◽  
Electric Arc Furnace ◽  
Electric Arc ◽  
Control Algorithms ◽  
Separate Analysis ◽  
Arc Furnace ◽  
Electric Arc Furnaces ◽  
Arc Furnaces

The aim of this study is to increase the efficiency of electric arc furnace through the use of advanced control algorithms for electrical modes. It was established that despite the common structure of the electric control system, as well as the approach to diagnosing the stage of the technological process, the criteria for switching from one combination of the furnace transformer tap and operating curve to another for electric arc furnaces and ladle furnaces are different. So, for EAF it is advisable to use a system in which a separate analysis of the signals of the relative effective value of the total even and odd harmonics of electric arc current (voltage) should be applied. It’s important to note that at the initial stage of melting it’s preferable to use even harmonics, and at the final stage of melting - odd harmonics. In it’s turn, during melting in LF, the argon blow mode and the slag mode have a significant role. Intensive blowing modes lead to the appearance of a metal mirror with the occurrence of bursts that occure short-circuit of the electric arc and lead to not optimal electric mode. According to the results of the analysis, a number of recommendations have been formulated that can have practical application in modernizing of modern control systems, aimed at optimizing production energy costs and reducing the unit cost of the final product of the metallurgical cycle. Moreover, the experience of implementing the described ides shows (for shaft-type electric arc furnace with capacity 125 ton, 85 MVA and ladle furnace 25 MVA) that the economic effect is 2.5% in terms of saving electric energy and 2% in terms of saving the consumption of electrodes. It’s a significant indicator taking into account the high energy intensity of modern electric steelmaking shops. This work was supported by the Ministry of Science and Higher Education of the Russian Federation (project No. FZRU-2020-0011).

scholarly journals Electric Arc Furnaces as a Cause of Current and Voltage Asymmetry

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5058
Author(s):  
Zbigniew Olczykowski
Keyword(s):  
Short Circuit ◽  
Electric Arc ◽  
Arc Furnace ◽  
High Current ◽  
Operating Characteristics ◽  
Electric Arc Furnaces ◽  
Arc Furnaces ◽  
Three Phase ◽  
Quality Analyzer ◽  
Theoretical Considerations

In the case of three-phase arc furnaces, two types of asymmetry can be distinguished: constructional and operational. The structural asymmetry is related to the construction of high-current circuits supplying the arc furnace. The knowledge of the parameters of the high-current circuit allows to determine the operating characteristics of the arc device. The author proposed a method for calculating the real values of the resistance and reactance of the high-current circuit. For this purpose, tests were made to short-circuit the electrodes with the charge. During the short-circuit, with the use of a power quality analyzer, measurements of electrical indicators were carried out, which allow to determine the parameters of the high-current circuit. A new method for determining voltage operational unbalance is also presented in this paper. The theoretical considerations presented in the article were verified in industrial conditions.

scholarly journals Researches Regarding the Air Pollution with Sulfur Dioxide (SO2) to the Steelmaking

2013 ◽  
Vol 8-9 ◽  
pp. 115-126 ◽  
Author(s):  
Dana Adriana Ilutiu-Varvara ◽  
Liviu Brandusan ◽  
Elena Maria Pică
Keyword(s):  
Air Pollution ◽  
Sulfur Dioxide ◽  
Electric Arc Furnace ◽  
Electric Arc ◽  
Arc Furnace ◽  
Steelmaking Process ◽  
Electric Arc Furnaces ◽  
Arc Furnaces ◽  
Technological Stage ◽  
Experimental Researches

The paper presents the experimental researches regarding the air pollution with sulfur dioxide (SO2) to the steelmaking in the electric arc furnace. It presents a method for determining the sulfur dioxide (SO2) concentrations from the steelmaking, the diagram variation of the sulfur dioxide (SO2) concentrations over time during specific technological stages of the steelmaking process and the potential sources that generate the sulfur dioxide (SO2) to steelmaking process in the electric arc furnaces. The air pollution during steelmaking in electric arc furnaces is manifested throughout this process, which includes the following technological stages: furnace charging, charge melting, refining, dephosphorization, desulphurization, deoxidizing, alloying and evacuation. Considering the stages of steelmaking in the electric arc furnace that have the potential to generate sulfur dioxide (SO2), it was assessed its generation evolution for the following technological stages: melting, refining, desulphurization and deoxidizing. The experimental researches were performed on two electric arc furnaces with a capacity of 10 and 30 tons. The highest concentrations of sulfur dioxide (SO2) were recorded during the desulfurization technological stage. After this stage, it has been recorded a significant reduction in sulfur dioxide (SO2) concentrations. The sulfur dioxide (SO2) concentrations from the electric arc furnace with the capacity of 30 tons are higher than those recorded in the furnace of 10 tons with 30-40%.

scholarly journals Research on Transient Power Quality of Large-capacity Electric Arc Furnace

2021 ◽  
Author(s):  
Liu Yang ◽  
Qinyue Tan ◽  
Di Xiong ◽  
Zhengguang Liu
Keyword(s):  
Power Quality ◽  
Reactive Power ◽  
Short Circuit ◽  
Electric Arc Furnace ◽  
Electric Arc ◽  
Normal Operation ◽  
Arc Furnace ◽  
Three Phase ◽  
Transient Power Quality

The overrun of transient power quality index caused by the large-capacity electric arc furnace (EAF) has become a prominent problem affecting the safe and stable operation of the power system. (1) In this paper, the relationship between arc furnace volt-age and current is derived based on the different stages of arc combustion, and the random variation of chaotic phenomenon of the arc voltage are simulated. Established an EAF model suitable for the study of transient power quality problems. (2) Take 50t AC EAF as an example to analyze the reactive power impact and the influence on the point of common coupling (PCC) voltage caused by the three-phase short circuit of the electrode. The results show that the experimental results are consistent with the theoretical analysis, verifying the correctness and effectiveness of the model. (3) When the three-phase short-circuit occurs, the reactive power impact is nearly 6 times that of normal operation, the short-circuit current is 2.66 times that of normal operation, and the effective value of the PCC voltage has dropped by 40.37%, which provides a theoretical basis for real-time compensation of impulsive reactive power and improvement of the transient power quality of the EAF.

Influence of the geometry arc furnace steel taphole on production parameters of the casting and rolling complex of JSC VMZ

2021 ◽  
pp. 11-16
Author(s):  
V. N. Lavrov ◽  
◽  
S. A. Botnikov ◽  
A. V. Kosonogov ◽  
S. A. Somov ◽  
...  
Keyword(s):  
Liquid Metal ◽  
Electric Arc ◽  
Arc Furnace ◽  
Electric Arc Furnaces ◽  
Production Parameters ◽  
Arc Furnaces ◽  
Casting And Rolling Complex ◽  
Liquid Residue ◽  
Furnace Steel ◽  
Furnace Slag

Currently the majority of modern electric arc furnaces (EAF) are equipped with bottom eccentric taphole system. This design allows to tap metal from EAF to ladle with the minimum amount of furnace slag, leaving a part of the liquid metal in EAF for subsequent heats (“liquid start”), if this residue is sufficient. In this case, taphole has several disadvantages: - it is not completely excluded that the oxidized furnace slag enters the ladle, especially with a low level of liquid residue in the EAF, the mass of captured slag in the ladle increases; - tapping time is unstable during taphole system campaign and depends on the wear of its constituent refractories; - periodically required to replace taphole refractories, thus it’s necessary to stop EAF. Under the conditions of the casting and rolling complex JSC “Vyksa Steel Works” work has carried out to change shape EAF’s taphole system, which made it possible to reduce the effect of these disadvantages on the efficiency of the EAF.

Measurement of polychlorinated dibenzo-p-dioxin and dibenzofuran emission from EAF steel making proces

2012 ◽  
Vol 57 (3) ◽  
pp. 811-821 ◽  
Author(s):  
T. Sofilic ◽  
J. Jendričko ◽  
Z. Kovačevic ◽  
M. Ćosić
Keyword(s):  
Treatment Plant ◽  
Electric Arc Furnace ◽  
Electric Arc ◽  
Drop Out ◽  
Steel Scrap ◽  
Arc Furnace ◽  
Electric Arc Furnace Dust ◽  
Arc Furnaces ◽  
Polycyclic Aromatic ◽  
Dust Treatment

Electric arc furnace (EAF) steel manufacturing is an important recycling activity which contributes to the recovery of steel resources and steel scrap/waste minimization. Because of the content of plastics, coatings and paintings as well as other nonferrous materials in the charge during melting, a strong emission of pollutants, including polluting substance group consists of persistent organic pollutions (POPs) represented by polycyclic aromatic hydrocarbon (PAH), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) occurs. This study was set out to investigate emissions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/Fs) from the stack of a new electric-arc furnace-dust treatment plant installed during modernisation of the Melt Shop in CMC SISAK d.o.o., Croatia. Obtained results have been compared with previously obtained results of PCDDs/Fs emission measurements from the old electric-arc furnace dust treatment without dust drop-out box, as well as quenching tower. The total PCDDs/Fs concentration in the stack off gases of both electric arc furnaces EAF A and EAF B were 0.2098 and 0.022603 ng I-TEQ/Nm3 respectively, and these results are close to previous obtained results by other authors. The calculated values of the emission factors for PCDDs/Fs calculated on the basis of measured PCDDs/Fs concentration in the stack off gases in 2008 and 2011 were 1.09 and 0.22 ng I-TEQ/ ton steel, respectively.

scholarly journals Process Improvements for Direct Reduced Iron Melting in the Electric Arc Furnace with Emphasis on Slag Operation

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 402
Author(s):  
Marcus Kirschen ◽  
Thomas Hay ◽  
Thomas Echterhof
Keyword(s):  
Steel Production ◽  
Electric Arc Furnace ◽  
Electric Arc ◽  
Raw Material ◽  
Steel Scrap ◽  
Process Conditions ◽  
Arc Furnace ◽  
Process Improvements ◽  
Direct Reduced Iron ◽  
Arc Furnaces

Steelmaking based on direct reduced iron (DRI, and its compacted derivative hot briquetted iron, HBI) is an anticipated important global alternative to current steel production based on FeOx reduction in blast furnaces due to its lower specific CO2 emission. The majority of DRI is melted and refined in the electric arc furnace with different process conditions compared to the melting of steel scrap due to its raw material composition being rather different. We provide data and analysis of slag composition of DRI charges vs. steel scrap charges for 16 industrial electric arc furnaces (EAFs). Suggestions for optimized slag operation and resulting process improvements of DRI melting in the EAF are given. A dynamic mass and energy model of the DRI melting in the EAF is introduced to illustrate the implications of the adapted slag operation on the EAF process with DRI charges.

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