Large Electric Arc Furnace Research Articles

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.

Forecasting Flicker Severity by Grey Predictor

Rapid voltage fluctuations in an electric power network may produce significant levels of flickers, which have negative impacts on human eyes and power system components. This paper proposes a grey predictor model for the forecast of the flicker severity level associated with operating a large electric arc furnace load. Actual measured flicker index data are adopted to implement the predictor model. Test results based on the proposed model are compared with another neural-network-based method. It shows that a more accurate forecast is achieved by using the proposed grey predictor model.

The Impact of Energy Prices on Technology Choice in the United States Steel Industry

In the last 30 years, U. S. steel producers have replaced their aging open hearth steel furnaces with basic oxygen (BOF) or large electric arc furnaces (LEF). This choice of technology creates the opportunity to substitute electricity for fossil fuels. We extend earlier research to investigate whether energy prices affect this type of technology adoption. The econometric model uses the “seemingly unrelated Tobit” method to capture the effects of the industry’s experience with both technologies, technical change, and potential cost reductions, as well as energy prices, on adoption. When we include the prices of electricity and coking coal as explanatory variables, the four energy price coefficients have the signs predicted by the law of demand, but the magnitude of the coefficients is such that the non-price terms are more important, e.g. a 50% increase in electricity prices would delay LEF adoption by only 12 days. Our results suggest that the adoption of LEF represents a form of major process technical change (factor biased - electricity using), rather than a price-induced technological innovation.

Acceleration of Melting by Burners in Large Electric Arc Furnace

Acceleration of Melting by Burners in Large Electric Arc Furnace

Use of tubular cooling panels on large electric-arc furnaces

Use of tubular cooling panels on large electric-arc furnaces

Large electric arc furnaces

There is considerably more that could be said about the furnace circuit. It has been the intention of this paper to touch on the aspects most vital at this present stage of development of large arc furnace circuits.

On the Operation of Large Electric Arc Furnace at Daido Steel Co., Chita Plant

On the Operation of Large Electric Arc Furnace at Daido Steel Co., Chita Plant

North Midland Power Section: Chairman's address. Power supply for large electric-arc furnaces

North Midland Power Section: Chairman's address. Power supply for large electric-arc furnaces

Layout of Large Electric Arc Furnace Plant

Layout of Large Electric Arc Furnace Plant

Some Problems on Large Electric Arc Furnace

Some Problems on Large Electric Arc Furnace

Transmission-line and system problems in supplying large electric-arc furnaces during wartime

Transmission-line and system problems in supplying large electric-arc furnaces during wartime

Transmission-line and system problems in supplying large electric-arc furnaces during wartime

ELECTRIC-ARC furnaces are contributing materially to the war effort, and a great number of them, small, medium, and large, have been installed recently, and more are being installed all over the country. These furnaces inherently produce a violently fluctuating load with widely different values in the several phases during the early part of the heat, referred to in the trade as “the meltdown period,” and the electric lines and systems to handle such loads must be carefully designed and installed so as to prevent such swinging loads from affecting adversely the system and other critical loads, particularly the lighting, and at the same time to provide sufficient capacity and voltage for satisfactory furnace operation. Also, such lines must be so arranged and connected into the system that the minimum of copper will be utilized — most important now.

Transmission-Line and System Problems in Supplying Large Electric-Arc Furnaces During Wartime

ELECTRIC-ARC furnaces are contributing materially to the war effort, and a great number of them, small, medium, and large, have been installed recently, and more are being installed all over the country. These furnaces inherently produce a violently fluctuating load with widely different values in the several phases during the early part of the heat, referred to in the trade as “the meltdown period,” and the electric lines and systems to handle such loads must be carefully designed and installed so as to prevent such swinging loads from affecting adversely the system and other critical loads, particularly the lighting, and at the same time to provide sufficient capacity and voltage for satisfactory furnace operation. Also, such lines must be so arranged and connected into the system that the minimum of copper will be utilized — most important now.

Large electric-arc furnaces — performance and power supply

Large electric-arc furnaces — performance and power supply

Transactions section: Large electric-arc furnaces — Performance and power supply

ELECTRIC arc furnaces are desirable loads for power systems, and are becoming more and more used for producing high-grade alloy steels, as well as for other types of steel. The authors believe that the data in this article will be of value and assistance to others in the solution of similar problems. It is necessary in connecting large electric arc furnaces onto power systems that it be done in such a manner that neither the voltage changes, caused by the violent and rapid load swings of these furnaces, will interfere with other load of the furnace customer nor be permitted to reflect back into the system in such a manner as to interfere with service to adjacent customers. Also precautions must be taken so that such widely fluctuating loads will neither interfere with the operations of any of the equipment on the power system nor interfere with any interconnection with adjacent power companies. Further, precautions must be taken so that voltage regulation caused by large short-time loads will not be too great.

Large Electric-Arc Furnaces-- Performance and Power Supply

In March l940, a 25-ton Heroult 3-phase electric arc furnace using a 10,000-kva 1.5 volts (115-volt base) for the 66-kv system with fluctuations from 3 per hour up to 15 per minute. Precautions were taken in the design of the furnace transformer to include separate reactance to reduce the load swings. Subsequently, it was found that this additional reactance was not eneded and it was removed, thereby improving the operation of the furnace. The load swings and accompaning voltage changes, after disconnecting the reactance, due to the operation of the first furnace, slightly exceeded the Duquesne Light Company standards. However, no complaints have been received from adjacent customers nor have any difficulties arisen from excessive operation of 4-kv distribution regulators, operation of the power stations, or interconnections.

Arc-furnace loads on long transmission lines

LARGE electric arc furnaces are loads which frequently introduce special technical problems when served from a central-station system. The fluctuations in the load taken by the furnaces are violent, and this characteristic combined with the inherently low power factor of this type of load results in a serious flicker problem. The low power factor also may require power-factor correction, in order to maintain a reasonable voltage level and reduce transmission losses. A further complication is that the arc is an excellent source of higher-harmonic currents and voltages. Where the load or the supply lines are close to telephone circuits, this may necessitate special measures to prevent telephone interference.

Arc-Furnace Loads on Long Transmission Lines

LARGE electric arc furnaces are loads which frequently introduce special technical problems when served from a central-station system. The fluctuations in the load taken by the furnaces are violent, and this characteristic combined with the inherently low power factor of this type of load results in a serious flicker problem. The low power factor also may require power-factor correction, in order to maintain a reasonable voltage level and reduce transmission losses. A further complication is that the arc is an excellent source of higher-harmonic currents and voltages. Where the load or the supply lines are close to telephone circuits, this may necessitate special measures to prevent telephone interference.