WO2017085330A1 - Système d'alimentation en énergie pour four électrique - Google Patents

Système d'alimentation en énergie pour four électrique Download PDF

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Publication number
WO2017085330A1
WO2017085330A1 PCT/EP2016/078361 EP2016078361W WO2017085330A1 WO 2017085330 A1 WO2017085330 A1 WO 2017085330A1 EP 2016078361 W EP2016078361 W EP 2016078361W WO 2017085330 A1 WO2017085330 A1 WO 2017085330A1
Authority
WO
WIPO (PCT)
Prior art keywords
electrodes
phase
power
secondary side
electrode
Prior art date
Application number
PCT/EP2016/078361
Other languages
German (de)
English (en)
Inventor
Mircea Ionita
Roland König
Martin Köneke
Original Assignee
Sms Group Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sms Group Gmbh filed Critical Sms Group Gmbh
Publication of WO2017085330A1 publication Critical patent/WO2017085330A1/fr

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B7/00—Heating by electric discharge
    • H05B7/02—Details
    • H05B7/144—Power supplies specially adapted for heating by electric discharge; Automatic control of power, e.g. by positioning of electrodes
    • H05B7/148—Automatic control of power
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/25—Process efficiency

Definitions

  • the invention relates to a power supply device for an electric furnace with reduction processes, for. Slag cleaning furnaces, FeCr-AC furnaces or FeNi-Submerged Arc Furnaces SAF.
  • the electrodes typically dip into slag that floats on a melt in the furnace.
  • a power supply device z. B. from WO 2007/048502 A1.
  • This application discloses a control apparatus for an AC reduction furnace.
  • the power supply device has at least one transformer with a primary side for connection to a supplied supply voltage and a secondary side for providing a secondary voltage.
  • the disclosed power supply device comprises two control devices for regulating the power input into the electric arc furnace.
  • Control means controls a height adjustment for the electrodes in the electric arc furnace.
  • a second closed-loop power control device connected between the secondary side and the electrode is designed to correct short fluctuations of electronic parameters.
  • This secondary-side crugelungseinnchtung has a phase control, with which it is possible to control the rms value of the secondary currents continuously.
  • the phase control is very fast compared to the previously mentioned and also occurring height adjustment of the electrodes. With the aid of the phase-angle control, it is possible to respond more quickly to a change in the electronic parameters of the process and thus to stabilize the furnace output.
  • the said height adjustment of the electrodes within the electric arc furnace takes place against the background that when lowering the Electrode in the melt, the material resistance, z. B. the slag resistance between two electrodes decreases. Thereafter, the electrode current automatically increases for the same power, as far as this is permitted by the corresponding electronic circuit.
  • the only way to achieve a desired further increase in active power is to allow a further increase in the secondary voltage provided by the
  • the electrodes of the furnace are immersed in highly conductive slag, e.g. As in cleaning furnaces for copper slag, or in particularly deeply immersed electrodes, however, there is the problem that - if the secondary voltage rises above a predetermined threshold - the power input into the electric furnace can no longer be effective, due to unwanted current flows within the slag between two electrodes ,
  • the said threshold value of the secondary voltage depends on the furnace design, the chemical composition of the melt, the charged materials and possibly other parameters. In other words: deep electrodes cause high electrode currents and, as a result, too high reactive power and, as a result, high apparent power.
  • Much of the input power does not arrive in the lower furnace area because it "fizzles out” and virtually dissipates, partly because it heats false slag zones, such as on the surface.
  • the known control system in which the power input is controlled by tap changer on the transformer and by changing the height position of the electrodes, reaches its limits, especially with low resistances. The controllability is then very difficult.
  • the choice of higher voltages leads
  • the current still “finds additional ways", ie, for example, via beds (coke, Möller, ...) or via slag flows between the electrodes and form unwanted micro-arcs
  • the invention is based on the object, a known This object is achieved according to the invention in that the power control device is designed to keep the power delivered to the electrode, in particular active power, constant even with an increase in the electrode current or only in the case of an increase in the electrode current to rise in a controlled manner by suitable lowering of the electrode voltage.
  • the power control device advantageously makes it possible to keep the power introduced into the melt, in particular active power, constant, or at least to increase it only in a controlled manner. This is especially true with unchanged setting of the tap changer on the transformer.
  • the present invention aims to at least indirectly limit the current and maintain the voltage at the lowest possible level, even with large electrode movements. Due to the immersion of the electrodes in the Möller and the slag, no arcs are usually formed; In this respect, the power control device according to the invention is also used at low powers, without arcs being present.
  • the power control is used to control the power input, especially in the Möller and / or the melt. This differs the power control according to the invention of the power control of WO 2007/048502 A1, which serves to keep the current and the voltage at a high voltage level constant with minimal electrode movements. In the WO document the power control is used to stabilize or maintain the arc in the oven.
  • the power control device comprises a thyristor circuit with a phase control for varying the firing angle of the thyristor.
  • the electrode current, the electrode voltage as well as the active power input into the furnace can be varied from their original values, as provided on the secondary side of the furnace transformer.
  • the energy supply device according to the invention is suitable for any forms of electric arc furnaces; These can be round, rectangular, oval or shaped differently.
  • the invention is not limited to the operation of electric arc furnaces with deep plunging electrodes or arcs, but rather the said power supply or the power control device according to the invention can also be used for furnaces, in whose operation an open arc is formed, ie where the electrode is not immersed in the melt or slag.
  • the description is a total of 8 figures attached, where
  • Figure 1 shows the energy supply device according to the invention for an electric furnace with lowerable electrodes
  • Power control device shows.
  • FIG. 1 shows an electric furnace 200 in which melt 220, electrically highly conductive slag 230 floating on the melt and melt 240 floating on the melt is located.
  • melt 220 electrically highly conductive slag 230 floating on the melt and melt 240 floating on the melt is located.
  • the electrical power provided on the secondary side is adjustable, typically via a tap changer.
  • the secondary side of the transformer 1 10 has two taps, with each of which one of the electrodes is connected via an electrical branch.
  • the power control device 120 according to the invention is connected. This is formed, the electrical power delivered to the electrodes, in particular, the active power to keep constant even at an increase in the electrode current or at least to increase only controlled by suitable lowering of the electrode voltage.
  • FIG. 2 to 4 show the power supply device according to the invention for an electric furnace 200, which is operated with three single-phase transformers 1 10.
  • FIGS. 5 to 7 show the operation of the electric furnace 200, each with a three-phase transformer 110.
  • a supply voltage U is provided for operating the energy supply device and the electric furnace.
  • the supply voltage is an input to a furnace switch 140 for switching on and off the electric furnace.
  • a tap changer 130 and the transformer 1 10 typically form a structural unit. Regardless of whether three single-phase transformers or in each case only a three-phase transformer is / is provided, the electrodes on the secondary side of the transformer 1 10 may be interconnected, for example in a Knappsackscnies ( Figures 2 and 5), a star or a delta connection.
  • the electrodes can also simply be connected to the taps of the phases on the secondary side of the transformer.
  • three power control devices 120 designed according to the invention are connected between the secondary side of the transformer and the electrodes, one for two phases.
  • FIG. Figure 8 is a graph plotted on the left ordinate with the secondary voltage of the furnace transformer and the thyristor voltage.
  • the ignition angle for driving the thyristors the electrode current and the active power are plotted.
  • the electrical resistance, in particular slag and melt resistance is shown, which decreases further from left to right, ie with increasing immersion depth.
  • This drop in the ohmic resistance in this case for example from 7 mOhm to 3 mOhm, inevitably leads to an increase in the electrode current, here by way of example from 29 kA to 42 kA.
  • the power control device effects that the electrical active power P introduced into the furnace remains essentially constant, in FIG. 8 at +/- 6.0 MW.
  • the power control device according to the invention in that they are the thyristors with increasing depth of immersion with an increasingly larger ignition angle, in Fig. 8, for example, accelerated from 36 ° to 84 °, whereby the output voltage decreases with increasing immersion depth of the electrodes, according to Figure 8 of initially 217 V at 7 mOhm to 169 V at 3 mOhm.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Discharge Heating (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)

Abstract

La présente invention concerne un dispositif d'alimentation en énergie destiné à un four électrique, notamment à un four de réduction comprenant au moins une électrode. Pour garantir, même lorsque les électrodes sont plongées dans la matière en fusion ou dans des scories à conductivité élevée, un apport efficace de puissance dans le four électrique, le dispositif d'alimentation en énergie selon l'invention présente un dispositif de réglage de puissance secondaire qui est conçu pour maintenir constante la puissance fournie à l'électrode, notamment la puissance active, même lors d'une augmentation de l'intensité d'électrode, ou pour ne permettre une augmentation de ladite puissance que de manière contrôlée, par un abaissement approprié de la tension d'électrode.
PCT/EP2016/078361 2015-11-19 2016-11-21 Système d'alimentation en énergie pour four électrique WO2017085330A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102015222845.2 2015-11-19
DE102015222845 2015-11-19

Publications (1)

Publication Number Publication Date
WO2017085330A1 true WO2017085330A1 (fr) 2017-05-26

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2016/078361 WO2017085330A1 (fr) 2015-11-19 2016-11-21 Système d'alimentation en énergie pour four électrique

Country Status (1)

Country Link
WO (1) WO2017085330A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109757003A (zh) * 2019-03-06 2019-05-14 重庆大朗冶金新材料有限公司 矿热炉自动控制方法
US11658585B2 (en) 2019-06-27 2023-05-23 Abb Schweiz Ag Arc furnace power supply with resonant circuit

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3508323A1 (de) * 1984-03-09 1985-09-12 Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt Einrichtung zur speisung einer oder mehrerer elektroden eines ein- oder mehrphasigen elektrothermischen ofens
US4683577A (en) * 1985-04-03 1987-07-28 Fried. Krupp Gesellschaft Mit Beschrankter Haftung Method and apparatus for regulating arc discharge furnace
DE4309640A1 (de) * 1993-03-25 1994-09-29 Abb Management Ag Gleichstrom-Lichtbogenofenanlage
WO2007048502A1 (fr) 2005-10-26 2007-05-03 Sms Demag Ag Dispositif de commande pour des fours de réduction à courant alternatif

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3508323A1 (de) * 1984-03-09 1985-09-12 Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt Einrichtung zur speisung einer oder mehrerer elektroden eines ein- oder mehrphasigen elektrothermischen ofens
US4683577A (en) * 1985-04-03 1987-07-28 Fried. Krupp Gesellschaft Mit Beschrankter Haftung Method and apparatus for regulating arc discharge furnace
DE4309640A1 (de) * 1993-03-25 1994-09-29 Abb Management Ag Gleichstrom-Lichtbogenofenanlage
WO2007048502A1 (fr) 2005-10-26 2007-05-03 Sms Demag Ag Dispositif de commande pour des fours de réduction à courant alternatif
DE102005051232A1 (de) * 2005-10-26 2007-05-03 Sms Demag Ag Steuervorrichtung für Wechselstrom-Reduktionsöfen

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109757003A (zh) * 2019-03-06 2019-05-14 重庆大朗冶金新材料有限公司 矿热炉自动控制方法
US11658585B2 (en) 2019-06-27 2023-05-23 Abb Schweiz Ag Arc furnace power supply with resonant circuit

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