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EP4360406A1 - Procédé de fonctionnement d'un four à arc électrique - Google Patents

Procédé de fonctionnement d'un four à arc électrique

Info

Publication number
EP4360406A1
EP4360406A1 EP22737558.1A EP22737558A EP4360406A1 EP 4360406 A1 EP4360406 A1 EP 4360406A1 EP 22737558 A EP22737558 A EP 22737558A EP 4360406 A1 EP4360406 A1 EP 4360406A1
Authority
EP
European Patent Office
Prior art keywords
control device
electrodes
phase
arc furnace
control
Prior art date
Legal status (The legal status 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 status listed.)
Granted
Application number
EP22737558.1A
Other languages
German (de)
English (en)
Other versions
EP4360406C0 (fr
EP4360406B1 (fr
Inventor
Thomas Matschullat
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Primetals Technologies Germany GmbH
Original Assignee
Primetals Technologies Germany 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 Primetals Technologies Germany GmbH filed Critical Primetals Technologies Germany GmbH
Publication of EP4360406A1 publication Critical patent/EP4360406A1/fr
Application granted granted Critical
Publication of EP4360406C0 publication Critical patent/EP4360406C0/fr
Publication of EP4360406B1 publication Critical patent/EP4360406B1/fr
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

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
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/52—Manufacture of steel in electric furnaces
    • C21C5/5211—Manufacture of steel in electric furnaces in an alternating current [AC] electric arc furnace
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B3/00—Hearth-type furnaces, e.g. of reverberatory type; Electric arc furnaces ; Tank furnaces
    • F27B3/08—Hearth-type furnaces, e.g. of reverberatory type; Electric arc furnaces ; Tank furnaces heated electrically, with or without any other source of heat
    • F27B3/085—Arc furnaces
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D19/00—Arrangements of controlling devices
    • 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
    • H05B7/18—Heating by arc discharge
    • H05B7/20—Direct heating by arc discharge, i.e. where at least one end of the arc directly acts on the material to be heated, including additional resistance heating by arc current flowing through the material to be heated
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D19/00—Arrangements of controlling devices
    • F27D2019/0028—Regulation
    • F27D2019/0034—Regulation through control of a heating quantity such as fuel, oxidant or intensity of current
    • F27D2019/0037—Quantity of electric current

Definitions

  • the present invention is based on an operating method for an arc furnace
  • a control device of the arc furnace controls an energy supply device of the arc furnace with first control values, first in a melting phase and then in a flat bath phase that follows the melting phase, so that the energy supply device draws electrical energy from a supply network and electrodes of the arc furnace via a furnace transformer and also controls a positioning device of the arc furnace with second control values, so that the positioning device positions the electrodes in the melting phase relative to steel-containing material in a furnace vessel of the arc furnace in a solid aggregate state, so that in the melting phase between the electrodes and the form steel-bearing material arcs, by which the steel-bearing material is melted into a molten steel, and positioned in the flat bath phase relative to the molten steel, so that in the F pool phase between the electrodes and the molten steel, arcs form which further heat the molten steel,
  • control device determines both the first control values and the second control values during the melting phase in such a way that electrical characteristics of the electrical energy supplied to the electrodes are approximated as closely as possible
  • control device determines the first control values during the flat bath phase in such a way that the electrical see parameters are approximated as closely as possible to the corresponding target values.
  • the present invention is also based on a control program for a control device of an arc furnace, the control program comprising machine code which can be processed by the control device, the processing of the machine code by the control device causing the control device to operate an arc furnace in accordance with such an operating method.
  • the present invention is also based on a control device for an arc furnace, the control device being programmed with such a control program so that the control device operates the arc furnace in accordance with such an operating method.
  • the present invention is also based on an arc furnace
  • the arc furnace has a furnace vessel to which steel-containing material can be fed in the solid state of aggregation
  • the arc furnace has an energy supply device and electrodes as well as a furnace transformer
  • the energy supply device is connected to a supply network on the input side and is connected to the electrodes on the output side via the furnace transformer,
  • the arc furnace has a positioning device, by means of which the electrodes can be positioned in a melting phase relative to the steel-containing material and in a flat bath phase following the melting phase relative to a molten steel produced by melting the steel-containing material,
  • the arc furnace has a control device by which the energy supply device can be controlled with first control values and the positioning device can be controlled with second control values both in the melting phase and in the flat bath phase, - wherein the control device is designed as explained above.
  • An operating method for an arc furnace is also known from WO 2019/207 611 A1.
  • the energy supply device for the electrodes of the arc furnace is designed as an intermediate circuit converter.
  • the intermediate circuit converter appears to be downstream of the furnace transformer.
  • WO 2019/207 611 A1 does not go into detail about the position control of the electrodes.
  • An operating method for an arc furnace is known from EP 3124 903 A1, in which a power supply device for the electrodes and a positioning device for the electrodes are controlled together as a function of electrical operating parameters of the arc furnace.
  • US Pat. No. 5,115,447 A discloses an operating method for an electric arc furnace during the so-called drilling phase, in which the electrodes are individually checked for short circuits and breakage of the arc, and if such a condition occurs, the electrode position is tracked.
  • the electrical energy is supplied to the electrodes of the electric arc furnace via a furnace transformer.
  • the furnace transformer is often connected to the supply network via a medium-voltage transformer.
  • the furnace transformer provides several voltage levels. For the area constant power and other high-current ranges, the respective voltage level can be selected at the furnace transformer. Fine control within a specific voltage level can be done, for example, by means of impedance control.
  • the electrode currents are subject to strong fluctuations.
  • the positioning of the electrodes is controlled mechanically, usually using hydraulic adjustment devices.
  • the mechanical adjustment of the electrodes has a significantly lower dynamic than the actual behavior of the arcs.
  • the fluctuations can therefore only be compensated for insufficiently.
  • the fluctuations lead to considerable stress on the components, for example the high-current cables, the current-carrying carrying arms, the hydraulic cylinders, etc.
  • the fluctuations occur both in the melting phase and in the flat bath phase.
  • the positioning of the electrodes must be continuously readjusted.
  • the readjustment can, for example, take place in such a way that a specific impedance or a specific power is controlled.
  • the dynamics of the positioning device are relatively low compared to the changes in the electrical system of the arc, certain fluctuations remain which cannot be can be regulated. The fluctuations are increased by wave movements and currents of the molten steel. As a result, the energy input into the molten steel is not optimal.
  • the object of the present invention is to create possi possibilities by means of which a quick and high-quality regulation of the arcs is possible in a simple and reliable manner in the flat bath phase.
  • an operating method of the type mentioned at the outset is designed in that the control device determines the second control values during the flat bath phase either completely independently of the electrical parameters or only as a function of the electrical parameters if the control device detects the danger based on the electrical parameters detects an arc break and/or a short circuit.
  • the first control values are thus determined by the control device during the flat bath phase—as in the prior art—in such a way that the electrical parameters are approximated as closely as possible to the corresponding setpoint values.
  • the second control values are determined independently of the electrical parameters, except when there is a risk of special operating states, which must be avoided at all costs. As a result, the electrode voltages and the electrode currents are tracked exclusively by adapting the activation of the energy supply device.
  • the electrical characteristics of the electrical energy supplied to the electrodes can be determined as required.
  • the electrical parameters can be the electrode currents.
  • the active currents in particular come into consideration as electrode currents.
  • the electrical parameters can also be the reactive currents and/or the apparent currents.
  • the electrical parameters can be the electrical power.
  • the active powers in particular come into question as powers. In individual cases, however, the electrical parameters can also be the reactive power and/or the apparent power.
  • the voltages applied to the electrodes and thus also the currents supplied to the electrodes are generally alternating quantities, ie alternating voltages and alternating currents.
  • Alternating variables can be characterized by their amplitude, their frequency and their course during a period (e.g. sinusoidal, triangular, sawtooth, rectangular, etc.). The course over time is preferably sinusoidal.
  • the amplitude must always be set appropriately.
  • the frequency can be kept constant in some cases. In other cases, however, it is preferable for the control device to determine the first control values during the flat bath phase in such a way that, in order to approximate the electrical parameters
  • a frequency of the electrode currents supplied to the electrodes and/or of the electrode voltages applied to the electrodes is also varied in accordance with the corresponding setpoint values. This approach offers greater flexibility in optimizing the operation of the arc furnace.
  • the frequency of the electrode currents supplied to the electrodes and/or of the electrode voltages applied to the electrodes in the flat bath phase is preferably lower than a base frequency of the supply network. This procedure has proven to be particularly advantageous in tests.
  • the electrodes are spaced apart from the surface of the molten steel. Consequently, the arcs have a base length at the beginning of the flat bath phase.
  • the control device In some situations it is advantageous for the control device to move the electrodes towards the molten steel during the flat bath phase, so that the arcs only have a remaining length that is smaller than the base length after moving towards the molten steel. In order to avoid the risk of a short circuit, a certain minimum length should not be undercut. For this reason, the remaining length is preferably at least 20% of the base length.
  • the base length can be determined or at least estimated using the electrical parameters as they exist at the beginning of the flat bath phase. It is possible that this determination/assessment is done intellectually by a person. However, it is preferably carried out by the control device.
  • control program with the features of claim 9.
  • the processing of the machine code by the control device causes the control device to operate an electric arc furnace in accordance with an operating method according to the invention.
  • control device having the features of claim 10.
  • the control device is programmed with a control program according to the invention, so that the control device operates the electric arc furnace in accordance with an operating method according to the invention.
  • control device is designed as a control device according to the invention.
  • FIG. 1 shows a block diagram of an arc furnace
  • FIG. 7 shows a modification of FIG. 6,
  • FIG. 12 shows a modification of FIG. 5
  • an arc furnace has a furnace vessel 1 .
  • Steel-containing material 2 can be fed to the furnace vessel 1--see FIG.
  • the steel-containing material 2 is the Ofenge vessel 1 supplied in a solid state.
  • the steel-containing material 2 can be scrap, for example.
  • the arc furnace also has an energy supply device 3 .
  • the energy supply device 3 is connected to a supply network 4 on the input side.
  • the supply network 4 is usually a medium-voltage network that has a nominal voltage in the 2-digit kV range and is operated at a base frequency f0 (see FIG. 11).
  • the base frequency f0 is usually 50 Hz or 60 Hz.
  • the supply network 4 is, as shown in FIG. 1, usually a three-phase network.
  • the arc furnace also has a furnace transformer 5 and electrodes 6 .
  • the power supply device 3 is connected on the output side to the 6 via the furnace transformer 5 with the electric.
  • a plurality of electrodes 6 are present and the furnace transformer 5 is further formed as a three-phase current transformer.
  • the electrode voltages U applied to the electrodes 6 are significantly below the nominal voltage of the supply network 4.
  • the electrode voltage U is only shown for one of the electrodes 6 in FIG.
  • the electrode voltages U are usually in the range of several 100 V. In individual cases, voltages above 1 kV are also possible. However, 2 kV is generally not exceeded.
  • switching devices are also available, by means of which the energy supply device 3 from the supply supply network 4 can be separated. Furthermore, switching devices can be present by means of which the energy supply device 3 can be separated from the furnace transformer 5 and/or the furnace transformer 5 from the electrodes 6 .
  • the switching devices perform purely binary switching operations, but no adjustment of voltages and currents. Furthermore, 5 active or passive filter devices can be arranged on the primary or secondary side of the furnace transformer. The switching devices and also the filter devices are of secondary importance for the mode of operation according to the invention and are therefore not shown in FIG. 1 (and also the other FIGs) for the sake of clarity.
  • the energy supply device 3 can obtain electrical energy from the supply network 4 and supply the electrical energy obtained to the electrodes 6 via the furnace transformer 5 .
  • the energy supply device 3 generally has a large number of semiconductor switches. Possible configurations of the energy supply device 3 are described in WO 2015/176899 A1 ("Gold Standard"). Alternatively, for example, the configurations according to EP 3124 903 A1 or EP 1026 921 A1 can also be used. Regardless of the specific configuration of the energy supply device 3, however, the energy supply device 3 is able on the output side - i.e. towards the furnace transformer 5 - to carry out a quasi-continuous gradation of the electrode voltages U applied to the electrodes 6 and/or the electrode currents I supplied to the electrodes 6. Analogous to the representation for the Electrode voltages U, the electrode current I in FIG. 1 is also shown for only one of the electrodes 6.
  • the arc furnace has a positioning device 7 .
  • the electrodes 6 can be positioned by means of the positioning device 7, as indicated by a double arrow 8 next to one of the electrodes 6 in FIG.
  • the positioning device 7 can have, for example, one or more hydraulic cylinder units.
  • the arc furnace has a control device 9 .
  • the energy supply device 3 and the positioning device 7 are (at least) controlled by the control device 9 .
  • the control device 9 thus generates first control values A1, with which it controls the energy supply device 3, and second control values A2, with which it controls the positioning device 7.
  • the energy supply device 3 and the positioning device 7 are operated in accordance with the respective control values A1, A2.
  • the control device 9 is designed as a software-programmable control device. This is indicated in FIG. 1 by the indication "mR" (for microprocessor-controlled). The mode of action and operation of the control device 9 is thus determined by a control program 10 with which the control device 9 is programmed can be processed by the control device 9. The processing of the machine code 11 by the control device 9 causes the control device 9 to operate the arc furnace according to an operating method, as will be explained in more detail below in connection with the other figures.
  • Step S1 is therefore only shown in broken lines in FIG.
  • the charging of the steel-containing material 2 is followed by a melting phase of the electric arc furnace.
  • the melting phase includes steps S2 to S4.
  • a flat bath phase follows the melting phase.
  • the shallow bath phase includes steps S5 through S7.
  • control device 9 determines the first control values A1 for the energy supply device 3 and the second control values A2 for the positioning device 7 in step S2. The determination takes place in accordance with FIG. 4 in corresponding determination blocks 12 and 13. In step S3 the control device 9 controls the Energy supply device 3 and the positioning device 7 according to the determined control values A1, A2.
  • the first control values A1 are determined in such a way that the energy supply device 3 draws electrical energy from the supply network 4 on the basis of the corresponding control and feeds it to the electrodes 6 via the furnace transformer 5 .
  • the second activation values A2 are determined in such a way that the positioning device 7 positions the electrodes 6 relative to the steel-containing material 2 .
  • the determination of the first control values A1 and the second control values A2 by the control device 9 is matched to one another in such a way that arcs 14 (see FIG. 2) form between the electrodes 6 and the steel-containing material 2. Through the arcs 14, the stahlhal term material 2 is melted and so gradually a molten steel 15 (FIG 5) generated.
  • the control device 9 is supplied with parameters U, I, P of the electrical energy supplied to the electrodes 6.
  • the parameters U, I, P can be, for example, the electrode voltages U and/or the electrode currents I and/or values derived therefrom.
  • Another derived value can result from the time profile of electrode voltages U and electrode currents I.
  • Such values are, for example, the active current, the active power, the apparent power, the reactive current and the reactive power.
  • the parameters can be given or derived for the entirety of the electrodes 6 or individually for the respective electrode 6 .
  • the control device 9 is also supplied with target variables U*, I*, P* for the characteristic variables U, I, P, for example target variables U*, I* for the electrode voltages U and/or or the electrode currents I or other suitable reference values (for example a reference value P* for the power P). Both the parameters U, I, P and the target values U*, I*, P* are supplied to the two determination blocks 12, 13 in the melting phase.
  • the control device 9 determines the first control values A1 and the second control values A2. The determination takes place in both determination blocks 12, 13 in such a way that the electrical parameters U, I, P are approximated as closely as possible to the corresponding setpoint values U*, I*, P*.
  • This procedure and thus the implementation of step S2 is generally known to those skilled in the art. It therefore does not need to be explained in more detail.
  • step S4 the control device 9 checks whether the melting phase has ended.
  • the melting phase is complete when the molten steel 15 has formed a continuous horizontal surface completely or at least essentially as shown in FIG. Either the steel-containing material 2 is completely melted or the elements of the steel-containing material 2 that have not yet melted are located completely under the surface of the steel melt 15 or the elements of the steel-containing material 2 that have not yet melted protrude only slightly above the surface of the steel melt 15 out. Furthermore can on the surface of the molten steel 15 a slag layer 16 have formed.
  • control device 9 It is possible for the control device 9 to evaluate actual variables of the electric arc furnace that have been recorded by measurement as part of the check as to whether the melting phase has ended. For example, it is possible for the control device 9 to evaluate the electrode currents I and/or the electrode voltages U, in particular their fluctuations.
  • the Steuereinrich device 9 can evaluate acoustic variables of the arc furnace, for example the noise level or the acoustic spectrum of the noise generated. Alternatively, it is possible for an operator (not shown) to specify to the control device 9 that the melting phase has ended.
  • step S2 If the melting phase has not yet ended, the controller 9 returns to step S2. On the other hand, when the melting phase has ended, the control device 9 goes to the shallow bath phase and thus to step S5.
  • control device 9 determines the first control values A1 for the energy supply device 3 and the second control values A2 for the positioning device 7 in step S5. In step S6 the control device 9 controls the energy supply device 3 and the positioning device 7 according to the determined control values Al, A2 on.
  • the first control values A1 are determined in such a way that the energy supply device 3 draws electrical energy from the supply network 4 on the basis of the corresponding control and feeds it to the electrodes 6 via the furnace transformer 5 .
  • the second control values A2 are determined in such a way that the positioning device 7 positions the electrodes 6 relative to the molten steel 15 .
  • the procedure for steps S5 and S6 corresponds to the procedure for steps S2 and S3.
  • the procedure of steps S5 and S6 also corresponds to the procedure of steps S2 and S3 in that the first control values A1 and the second control values A2 are matched to one another in such a way that arcs 14 form.
  • the arcs 14 form in the flat bath phase, however, as shown in FIG. 5, between the electrodes 6 and the molten steel 15 .
  • the molten steel 15 is further heated up by the arcs 14 .
  • the control device 6 is also supplied with the parameters U, I, P of the electrical energy supplied to the electrodes 6 and the associated setpoint variables U*, I*, P*.
  • the parameters U, I, P and the associated setpoint values U*, I*, P* are only supplied to the determination block 12 within the control device 9 .
  • the control device 9 thus continues to determine the first control values A1 in such a way that the electrical parameters U, I, P are approximated as closely as possible to the corresponding setpoint values U*, I*, P*.
  • the control device 9 uses the determination block 17 to determine the second control values A2 in the flat bath phase. In particular, it is possible for the control device 9 to determine the second control values A2 completely independently of the electrical parameters U, I, P, as shown in FIG. In this case it is possible that the determination block 17 according to the illustration in FIG. 6 is not supplied with the electrical parameters U, I, P at all. Instead, the control device 9 can determine the second control values A2 on the basis of another internal determination or on the basis of external specifications V (for example specifications that originate from an operator).
  • step S7 the control device 9 checks whether the flat bath phase has ended. It is possible for the control device 9 to evaluate measured actual values of the arc furnace as part of the check as to whether the flat bath phase has ended. Alternatively, it is possible for the operator to tell the control device 9 that the shallow bath phase has ended.
  • step S8 the steel melt ze 15 produced is removed from the furnace vessel 1, for example poured into a ladle (not shown). This process can, but does not have to, take place under the control of the control device 9 . Step S8 is therefore only shown in dashed lines in FIG. 3—similar to step S1.
  • step S8 With the execution of step S8, a complete cycle in the operation of the arc furnace is completed. A new cycle can therefore be started, beginning with step S1.
  • the second control values are determined, as already mentioned, independently of the electrical parameters U, I, P.
  • the second control values A2 from the determination block 17 can be generally independent of the electrical parameters U, I, P can be determined, but can still be taken into account under special circumstances.
  • the corresponding electrical parameters U, I, P are supplied to the determination block 17 in accordance with the representation in FIG. A supply of the corresponding setpoint values U*, I*,
  • the determination block 17 (and because the determination block 17 is part of the control device 9, as a result the control device 9) checks in this case whether the electrical characteristics U, I, P he fill predetermined conditions or not. In particular, the determination block 17 checks in this case whether, based on the electrical parameters U,
  • FIG. 8 shows the procedure in the flat bath phase.
  • the procedure before in the melt phase can be unchanged.
  • step Sil the control device 9 checks whether it recognizes the risk of an arc break.
  • the control device 9 evaluates the electrical parameters U, I, P as part of the check in step Sil. If the control device 9 detects the risk of an arc breaking, it goes to a step S12.
  • step S12 the control device 9 determines the first control values A1 and the second control values A2 such that the risk of the arc breaking is counteracted. For example, the control device 9 can vary the first actuation values A1 such that the electrode voltages U are increased, and the second actuation values A2 can vary such that the electrodes 6 are lowered in the direction of the molten steel 15 .
  • step S13 the control device 9 checks whether it recognizes the risk of a short circuit. As part of the check of step S13, the control unit evaluates direction 9 also the electrical parameters U, I, P. If the control device 9 detects the risk of a short circuit, it goes to a step S14. In step S14, the control device 9 determines the first control values A1 and the second control values A2 such that the risk of a short circuit is counteracted.
  • control device 9 can vary the first control values A1 in such a way that the electrode voltages U are reduced, and in particular the second control values A2 can be varied in such a way that the electrodes 6 are raised in the direction away from the molten steel 15 .
  • step S13 If the control device 9 does not recognize the risk of a short circuit in step S13, the control device 9 goes to step S5.
  • step S5 the first control values A1 and the second control values A2 are determined in the manner already explained in connection with FIG.
  • step S12 the control device 9 next moves to step S6, in which it controls the energy supply device 3 and the positioning device 4 according to the determined first and second control values Al, drives A2. Then the controller goes to step S7. From there, there is either a transition to step S8 or the control device 9 returns to step Sil.
  • the parameters U, I, P can be selected in different ways. For example, according to the representation in FIG. 9, it is possible that—at least during the flat bath phase—the electrical parameters U, I, P are the electrode currents I. Alternatively, according to the illustration in FIG. 10, it is possible for the electrical parameters U, I, P to be the electrical power P—at least during the flat bath phase.
  • the determination block 12 can be preceded by a supplementary block 18 .
  • the supplementary block 18 can Voltages U and the electrode currents I are supplied.
  • the supplementary block 18 determines, for example, the instantaneous power instantaneously or the average electrical power over a period of the electrode voltages U and outputs the determined value as an electrical parameter P to the determination block 12 .
  • control device 9 determines the first control values A1 during the flat bath phase in such a way that a frequency f of the electrode voltages U (or correspondingly a frequency f of the electrode currents I) is varied. This is indicated in FIG. 11 by the fact that a corresponding period duration T is varied. The variation in the period duration T and the corresponding frequency f is indicated by a double arrow 19 in FIG. It is done for the purpose of approximating the electrical parameters U, I, P to the corresponding setpoint values U*, I*, P*.
  • the frequency f is preferably varied in a range which is between 70% and 90% of the base frequency f0, in particular between 75% and 85% of the base frequency f0.
  • the arcs 14 have a base length L0 as shown in FIG.
  • the control device 9 moves the electrodes 6 towards the molten steel 15 during the flat bath phase.
  • the arcs 14 according to FIG. 12 only have a remaining length LR.
  • the remaining length LR is smaller than the base length L0.
  • the base length L0 can be made known to the control device 9 in various ways.
  • the base length L0 of the control device 9 can be set by the operator be specified.
  • the control device 9 determines the base length L0 in step S21 using the electrical parameters U, I, P as they exist at the beginning of the flat bath phase. Appropriate procedures are known to those skilled in the art.
  • Step S21 if present, is executed only once. It is therefore not included in the loop of steps S5 to S7. This also applies in an analogous manner if steps S11 to S14 are present.
  • control device 9 determines the remaining length LR using the base length L0. Alternatively, it is possible for the control device 9 to determine only a minimum permissible value for the remaining length LR, or for the control device 9 to be given a corresponding minimum permissible value for the remaining length LR. In this case, it is possible for the control device 9 to continue moving the electrodes 6 until the control device 9 recognizes optimized operation of the arc furnace based on an evaluation of the parameters U, I, P or the residual length RL reaches the minimum permissible value.
  • step S5 is implemented in this case in such a way that the first control values A1 are determined as already explained, but the second control values A2 are determined in such a way that the length of the arcs 14, starting from the base length L0, is reduced.
  • the energy efficiency of the arc furnace can be improved in some operating states of the arc furnace.
  • the present invention has many advantages. In particular, however, the mechanical load on the positioning device 7 can be reduced and the energy efficiency during operation of the arc furnace can continue to be improved.
  • the invention was illustrated and described in detail by the preferred exemplary embodiment, the invention is not restricted by the disclosed examples and other variants can be derived from this by a person skilled in the art without leaving the protective scope of the invention.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Plasma & Fusion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Power Engineering (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
  • Furnace Details (AREA)

Abstract

Un dispositif de commande (9) d'un four à arc électrique commande, dans une phase de fusion et ultérieurement dans une phase de bain plat, un dispositif d'alimentation en énergie (3) à l'aide de premières valeurs de commande (A1), de telle sorte que ledit dispositif d'alimentation en énergie fournit de l'énergie électrique à des électrodes (6) du four à arc électrique par l'intermédiaire d'un transformateur de four (5). Le dispositif de commande, dans les deux phases, commande en outre un dispositif de positionnement (7) à l'aide de secondes valeurs de commande (A2), de telle sorte que ledit dispositif de positionnement positionne les électrodes (6) par rapport à un matériau contenant de l'acier encore non fondu (2) dans la phase de fusion et par rapport à l'acier fondu (15) dans la phase de bain plat. En conséquence, des arcs électriques (14) sont formés dans les deux phases, au moyen desquels le matériau contenant de l'acier (2) est fondu ou l'acier fondu (15) est encore chauffé. Pendant la phase de fusion, les premières valeurs de commande (A1) et les secondes valeurs de commande (A2) sont déterminées de telle sorte que des paramètres électriques (U, I, P) de l'énergie électrique fournie aux électrodes (6) soient rapprochés autant que possible de variables cibles correspondantes (U*, I*, P*). Dans la phase de bain plat, cela s'applique uniquement aux premières valeurs de commande (A1). Les secondes valeurs de commande (A2), en revanche, sont déterminées soit complètement indépendamment des paramètres électriques (U, I, P), soit en fonction des paramètres électriques (U, I, P) uniquement si le risque d'une rupture d'arc électrique et/ou d'un court-circuit est identifié en fonction des paramètres électriques (U, I, P).
EP22737558.1A 2021-06-22 2022-06-09 Procédé de fonctionnement pour un four à arc Active EP4360406B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP21180899.3A EP4110015A1 (fr) 2021-06-22 2021-06-22 Procédé de fonctionnement pour un four à arc
PCT/EP2022/065633 WO2022268511A1 (fr) 2021-06-22 2022-06-09 Procédé de fonctionnement d'un four à arc électrique

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EP4360406A1 true EP4360406A1 (fr) 2024-05-01
EP4360406C0 EP4360406C0 (fr) 2025-06-18
EP4360406B1 EP4360406B1 (fr) 2025-06-18

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EP21180899.3A Withdrawn EP4110015A1 (fr) 2021-06-22 2021-06-22 Procédé de fonctionnement pour un four à arc
EP22737558.1A Active EP4360406B1 (fr) 2021-06-22 2022-06-09 Procédé de fonctionnement pour un four à arc

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US (1) US20240284566A1 (fr)
EP (2) EP4110015A1 (fr)
JP (1) JP7758763B2 (fr)
CN (1) CN117598028A (fr)
BR (1) BR112023024937A2 (fr)
MX (1) MX2023014837A (fr)
WO (1) WO2022268511A1 (fr)

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Publication number Priority date Publication date Assignee Title
EP4426067B1 (fr) * 2023-03-02 2025-12-17 GE Energy Power Conversion Technology Ltd Système d'alimentation électrique pour four à arc et four à arc et procédé associés
DE102023106881A1 (de) * 2023-03-20 2024-09-26 Sms Group S.P.A. Verfahren zum Regeln eines Betriebs eines elektrischen Ofens und elektrischer Ofen zum Schmelzen von Schmelzmaterial
EP4436315B1 (fr) 2023-03-22 2024-11-27 Badische Stahl-Engineering GmbH Dispositif d'alimentation en courant pour un appareil métallurgique

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US5115447A (en) * 1991-01-10 1992-05-19 Ucar Carbon Technology Corporation Arc furnace electrode control
US5991327A (en) 1995-10-26 1999-11-23 Inverpower Controls Ltd. Smart predictive line controller for AC and DC electric arc furnaces
JP3534693B2 (ja) 2000-06-19 2004-06-07 三菱重工業株式会社 プラズマ灰溶融炉の運転方法
JP2005036997A (ja) 2003-07-16 2005-02-10 Toshiba Corp アーク炉の電極昇降制御装置
EP2947766A1 (fr) 2014-05-19 2015-11-25 Siemens Aktiengesellschaft Alimentation électrique pour une charge non linéaire dotée de convertisseurs matriciels à plusieurs niveaux
ITUB20152674A1 (it) 2015-07-30 2017-01-30 Danieli Automation Spa Apparato e metodo di alimentazione elettrica di un forno elettrico ad arco
IT201800004846A1 (it) 2018-04-24 2019-10-24 Metodo di alimentazione elettrica di un forno elettrico ad arco e relativo apparato

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MX2023014837A (es) 2024-01-15
US20240284566A1 (en) 2024-08-22
EP4360406C0 (fr) 2025-06-18
BR112023024937A2 (pt) 2024-02-15
WO2022268511A1 (fr) 2022-12-29
JP7758763B2 (ja) 2025-10-22
EP4110015A1 (fr) 2022-12-28
JP2024526164A (ja) 2024-07-17
CN117598028A (zh) 2024-02-23
EP4360406B1 (fr) 2025-06-18

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