Method for controlling the operation of an electric furnace and an electric furnace for melting molten material

Abstract

The present invention relates to a method for adjusting the operation of an electric furnace (10) during a melting process of a molten material, the method comprising: - a step (S1) of model predictive calculation of a target course of at least one operating characteristic (Op) up to a planned period (N) based on the results to be achieved in the melting process; and - a step (S2) of setting at least one operating characteristic (Op) by electrode positioning means (30) and / or power supply means (50) such that at least one operating characteristic (Op) is on the target course of at least one operating characteristic (Op) at a predetermined future point in time. The present invention further relates to an electric furnace (10) configured to perform a method for adjusting the operation of the electric furnace (10) during a melting process of a molten material.

Description

Technical Field

[0001] The present invention relates to a method for adjusting the operation of an electric furnace during the melting process of a molten material, and an electric furnace configured to execute the method for adjusting the operation of the electric furnace.

Background Art

[0002] Molten materials, particularly metals, are periodically melted and heated in a melting unit during the melting process. These electrically operated melting units, particularly electric furnaces such as electric arc furnaces, electric reduction furnaces, and / or submerged arc resistance furnaces, operate with direct current (DC), alternating current (AC), or polyphase alternating current.

[0003] The melting process for melting a material typically includes at least one melting cycle. The melting cycle usually includes, but is not limited to, different operating steps as follows. - A step of charging the melting unit with a molten material, usually scrap and / or direct reduced iron (DRI). - A step of generating an electric arc between the molten material and the electrodes of the furnace. - A step of piercing the molten material to initiate the melting process. - A step of forming a molten bath of the molten material. [[ID=2�]]<> - A step of purifying the molten material and adjusting the temperature and material composition of the molten bath. - A step of removing the molten material in the electric furnace. - A step of tapping the molten material present in the electric furnace.

[0004] During different operating steps of the melting cycle of the melting process, the operating characteristics of the electric furnace exhibit different values depending on the specific results to be achieved. The operating characteristics of the electric furnace include, but are not limited to, voltage, current, electrical frequency, and electrode position. The specific results to be achieved in the melting process include, but are not limited to, minimizing the time required to complete the melting process, minimizing the wear of the electric furnace, and minimizing the amount of electrical energy required to complete the melting process.

[0005] Conventional methods for adjusting the operation of an electric furnace during the melting process of a molten material involve setting the operating characteristics of the electric furnace according to a fixed target course of these operating characteristics, depending on a given molten material and a specific result to be achieved. In this way, for example, a fixed, given target amount of power to be transmitted to the molten material in a particular operating step of the melting cycle is achieved, for example, by adjusting electrode positions and / or current and / or voltage.

[0006] However, these known types of methods for adjusting the operation of an electric furnace during the melting process of a molten material have drawbacks related to the wide range of fluctuations in instantaneous power absorption obtained from the power network, particularly but not limited to, that occur during the drilling of the molten material. The collapse of the molten material causes short circuits and disturbances in the electric arc. Considering this instantaneous variability in power absorption by the electric furnace, voltage fluctuations occur in the supplying power network, causing the so-called flicker phenomenon. This instantaneous variability in power absorption can be measured by the so-called dynamic factor. The dynamic factor is defined as the ratio between the measured actual reactance of the entire electric furnace and the reactance in the electric circuit of the electric furnace. Furthermore, this instantaneous variability in power absorption by the electric furnace leads to suboptimal process conditions, such as increased wear, particularly of the electrodes and the furnace, and increased consumption of electrical energy for a given amount of molten material. [Overview of the project] [Problems that the invention aims to solve]

[0007] The present invention is based on the problem of providing a method for adjusting the operation of an electric furnace during the melting process of a molten material, which can reduce instantaneous fluctuations in power absorption by the electric furnace and thus minimize dynamic factors throughout the entire melting process of the molten material. [Means for solving the problem]

[0008] The underlying problem of the present invention is solved by a method for adjusting the operation of an electric furnace during the melting process of a molten material as described in claim 1. Advantageous embodiments of this method are described in claims dependent on claim 1.

[0009] More specifically, the problem underlying the present invention is solved by a method for coordinating the operation of an electric furnace during the melting process of a molten material, the electric furnace comprising electrode positioning means for positioning at least one electrode (preferably a plurality, e.g., two or three or more electrodes) of the electric furnace, power supply means for supplying power to the at least one electrode, and electronic control means data-coupled to the electrode positioning means and the power supply means for transmitting signals. The method comprises the following process steps. - A step of model predicting and calculating the target course of at least one operating characteristic up to the planned period, based on the desired outcome of the melting process, - A step of setting at least one operating characteristic by electrode positioning means and / or power supply means such that at least one operating characteristic is on a target course for at least one operating characteristic at a predetermined future point in time.

[0010] The method according to the present invention has the advantage that the deviation of at least one operating characteristic from its optimal value at any given time is significantly reduced. This results in a significant reduction in the instantaneous variability of power absorption by the electric furnace, and therefore helps to reduce flicker in the power supply network, while simultaneously increasing the overall energy efficiency of the electric furnace. For example, the deviation of the current of at least one electrode from its optimal value at any given time is reduced for the minimum amount of electrical energy required to heat the molten material to a predetermined temperature.

[0011] The melting process may include one or more melting cycles. A melting cycle may include the following operational steps: - The process of feeding molten material, usually scrap and / or directly reduced iron (DRI), into the furnace. - A process of generating an electric arc between the molten material and the furnace electrodes. - A step of drilling holes in the molten material to initiate the melting process, - A process of forming a molten bath of molten material, - A process of refining the molten material and adjusting the temperature and material composition of the molten bath. - A process to remove molten material from inside an electric furnace. - The process of removing molten material from inside an electric furnace.

[0012] The melting cycle may further include additional operating steps that can be performed sequentially and / or in parallel with the above operating steps, and these additional operating steps are not limited to, - A step of using a gas burner and / or oxygen lance to further heat the molten material. - A process of adjusting the chemical composition of the molten material by using an oxygen lance within the molten material. - The process includes a step of adjusting the chemical composition of the molten material by injecting additives such as carbon, lime and / or dolomite, or any combination thereof, into the molten material.

[0013] A melting cycle may include further operating steps specific to a particular molten material and / or results achieved during the melting process. Further operating steps of a melting cycle may include injecting additives and / or alloying elements into the molten material. A particular operating step of a melting cycle may be repeated several times within a single melting cycle.

[0014] The electric furnace may be an electric arc furnace, an electric reduction furnace, or a submerged arc resistance furnace. The electric furnace may operate on direct current (DC), alternating current (AC), or multiphase alternating current.

[0015] The molten material may include metallic materials, particularly steel materials, and / or directly reduced iron materials. The molten material may also include scrap materials, particularly scrap metal materials. The molten material may include aluminum, copper, silver, gold, or any other metallic materials that can be heated and / or melted with electrical energy.

[0016] The electrodes can be manufactured from high-density graphite and / or tungsten. The electrodes can be designed to transmit electrical energy while forming an arc between the tip and the filler material. The electrodes can be pre-fired electrodes, self-firing electrodes (Soderberg electrodes), and / or extruded / composite electrodes (electrodes formed by combining a Soderberg electrode and a pre-fired electrode as a core), and / or hollow electrode systems. Thus, the selection of the electrode type depends on economic aspects such as the size of the electrode, manufacturing materials / metallurgy, and / or operating costs.

[0017] The electrode positioning means may include height adjustment means configured to move at least one electrode of the electric furnace closer to or farther from the molten material in the electric furnace. The height adjustment means can use any of a direct electromechanical drive device including an electric winch hoist, a hydraulic cylinder, a pneumatic cylinder, an electric motor, and / or a gear. In this way, the position of at least one electrode can be adjusted more quickly and with higher accuracy.

[0018] The power supply means may include a plurality of converters configured to supply power to at least one electrode of the electric furnace.

[0019] The power supply means may include a plurality of DC-AC converters and / or AC-DC-AC converters configured to supply power to at least one electrode of the electric furnace. In this way, the electric furnace can be operated with an alternating current, particularly a polyphase alternating current.

[0020] The power supply means may include a plurality of AC-DC converters and / or DC-DC converters and / or DC choppers configured to supply power to at least one electrode of the electric furnace. In this way, the electric furnace can be operated with direct current.

[0021] The electronic control means may be any electronic system adapted to receive, and / or store, and / or process, and / or transmit signals. The electronic control means may be any electronic system adapted to control and / or adjust the power supply means in response to at least one signal and / or to control and / or adjust the electrode positioning means in response to at least one signal.

[0022] The electric furnace may comprise one or more sensors for providing information regarding harmonic distortion and / or flicker and / or the ratio of active power flow to reactive power flow in the supply power network and / or at least one operating characteristic of the electric furnace. The electronic control means is operably connected to one or more such sensors, receives and processes the sensor signals, and can use them to control and / or adjust the power supply means and / or the electrode positioning means.

[0023] The one or more sensors may be sensors that use optical measurement means and / or electrical measurement means and / or magnetic measurement means and / or mechanical measurement means and / or magnetostrictive measurement means to measure one or more measured quantities in order to provide sensor signals to the electronic control means.

[0024] The one or more measured quantities may directly and / or indirectly correspond to harmonic distortion and / or flicker and / or the ratio of active power flow to reactive power flow in the supply power network and / or at least one actual operating characteristic of the electric furnace. In this way, the positioning of the sensors within the electric furnace can be made more flexible.

[0025] For example, if at least one actual operating characteristic is current, the one or more measured quantities may directly correspond to the current. In other words, the measured quantity may be current.

[0026] For example, if at least one actual operating characteristic is electrode position, then at least one meter may indirectly correspond to the electrode position. In other words, the meter may be the pressure in a hydraulic cylinder used to position at least one electrode, and the pressure in the hydraulic cylinder may correspond to a specific electrode position with respect to the molten material in the electric furnace.

[0027] The electronic control means may include a storage element configured to store sensor signals received from an electric furnace by one or more sensors.

[0028] The electronic control means may include a housing. The electronic control unit may be an integrated component.

[0029] In the context of the present invention, “housing” is designed to protect designated internal components from external influences, particularly mechanical and / or electrical influences. Furthermore, the housing can provide an electrical grounding connection, thereby enhancing safety in a predetermined manner for personnel in the vicinity of the electrical components enclosed by the housing.

[0030] The housing may comprise a bottom, a top, and at least one side. The bottom, top, and at least one side can at least partially limit the housing volume. The bottom, top, and at least one side can be connected to each other to form an integrated component.

[0031] In the context of the present invention, the two components forming an integrated component are interconnected by at least one mechanical connection. In other words, the two components forming an integrated component change their relative spatial positions to each other within the limits of their mechanical connection when the integrated component is moved from one spatial position to another.

[0032] In a preferred embodiment of the present invention, the mechanical connection of the integrated component is fixed. In other words, the relative positions of the two parts forming the integrated component, where the mechanical connection between the two parts is fixed, remain constant during changes in the spatial position of the integrated component.

[0033] The model prediction calculation is based on mathematical formulas known to those skilled in the art to describe the functional and physical correlations of electric furnaces during the melting process of molten materials.

[0034] The operating characteristics may be any characteristics of the electric furnace during operation. For example, the operating characteristics may be voltage, current, electrical frequency, electrode position, etc.

[0035] The target course of the operating characteristics is a predetermined course of operating characteristics calculated to achieve a specific outcome in the melting process.

[0036] The planning period can be any amount of time, in particular, the amount of time from the start of the melting process to the end of the melting process.

[0037] The desired outcomes of a melting process can be applied to the entire melting process and / or to specific operating steps within the melting cycle of the melting process. For example, minimizing the electrical energy required to heat a given amount of molten material to a predetermined temperature can be applied to the entire melting process and / or to specific operating steps within the melting cycle of the melting process. Different operating steps within the melting cycle of the melting process may include different outcomes to be achieved. For example, in the operating step of drilling the molten material to initiate the melting process, the desired outcome may be minimizing the time required to heat the molten material to a predetermined temperature. In the subsequent operating step of forming the molten bath of the molten material, the desired outcome may be minimizing the electrical energy required to heat the molten material to a predetermined temperature. Methods designed in this manner have the advantage of improving the energy and time efficiency of the melting process while simultaneously improving the quality of the molten material at the furnace outlet.

[0038] More preferably, the method is designed to include a method step for determining at least one actual operating characteristic supplied to at least one electrode by electrode positioning means and / or power supply means in a first time, and to include a method step for model predicting the target course of at least one operating characteristic up to a planned period such that the target course of at least one operating characteristic in the first time is equal to the actual operating characteristic in the first time.

[0039] In this way, the overall control and adjustment of the electric furnace can be improved. The target course of at least one operating characteristic is continuously updated, thus enabling more precise control and adjustment of at least one operating characteristic, even when considering sudden changes in conditions within the electric furnace during the melting process. In fact, the target course is no longer a static target course as known from the prior art, but is calculated continuously throughout the entire melting process, resulting in improved control and adjustment of the electric furnace based on predictive control and adjustment rather than conventional correction-based control and adjustment.

[0040] A method step for determining at least one actual operating characteristic in a first time may be carried out by at least one sensor.

[0041] More preferably, the method is designed to provide a method step for setting at least one operating characteristic such that at least one operating characteristic is on a target course in a second time following a first time in terms of time.

[0042] In this way, the method has the advantage that at least one operating characteristic can follow the target course faster, enabling an increase in control and adjustment speed, and thus further improving the overall control and adjustment of the electric furnace.

[0043] The characteristic that the second time period follows the first time period in terms of time can also be expressed in the sense that the second time period is after or downstream of the first time period.

[0044] More preferably, the method provides a method step for determining at least one actual operating characteristic supplied to at least one electrode by electrode positioning means and / or power supply means in a third time, wherein the third time is designed to follow a second time in terms of time, and the method step of model predictive calculation of a target course of at least one operating characteristic up to a planned period is designed to be performed such that the target course of at least one operating characteristic in the third time is equal to the actual operating characteristic in the third time.

[0045] In this way, the method has the advantage that the overall control and adjustment of the electric furnace can be further improved because the target course of at least one operating characteristic is continuously updated, and therefore sudden changes in conditions inside the electric furnace during the melting process are also taken into account. Such changes may include, but are not limited to, sudden changes in the electrode position relative to the molten material due to the collapse of the molten material during the melting process.

[0046] The characteristic that the third time period follows the second time period in terms of time can also be expressed as the third time period being later or downstream in terms of time than the second time period.

[0047] More preferably, the method is designed to provide a method step for setting at least one operating characteristic such that at least one operating characteristic is on a target course in a fourth time following a third time in terms of time.

[0048] In this way, the method has the advantage that at least one operating characteristic can follow the target course faster, enabling an increase in control and adjustment speed, and thus further improving the overall control and adjustment of the electric furnace.

[0049] The fact that the fourth time follows the third time in terms of time can also be expressed as the fourth time being later or downstream in terms of time than the third time.

[0050] The first, second, third, and fourth periods may fall within the scope of the planned period.

[0051] The above-described method steps may be continued continuously throughout the entire melting process within the planned period.

[0052] More preferably, this method is designed to exhibit the following process steps. - A step of model predicting and calculating the target course of n operating characteristics up to the planned period, based on the desired outcome of the melting process, - A step of setting n operating characteristics by electrode positioning means and / or power supply means such that each of the n operating characteristics is located in the respective target course associated with each operating characteristic at a predetermined future point in time.

[0053] In this way, this method has the advantage of improving the overall control and adjustment of the electric furnace by enabling the simultaneous control and adjustment of multiple operating characteristics.

[0054] The number n of operating characteristics is not limited to a specific quantity and can be any integer. For example, n can be 2 or greater, preferably 5 or greater, and particularly preferably 35 or greater. In a preferred embodiment, the number n of operating characteristics may be equal to 4.

[0055] More preferably, the method is designed such that the method comprises a method step for determining n actual operating characteristics supplied to at least one electrode by electrode positioning means and / or power supply means in a first time, and a method step for model predicting and calculating the target course of each of the n operating characteristics up to the planned period is performed such that the target course of each operating characteristic in the first time is equal to the actual operating characteristic in the first time.

[0056] In this way, the method has the advantage that the target courses of n operating characteristics are continuously updated, and therefore, sudden changes in conditions inside the electric furnace during the melting process are also taken into account, thus further improving the overall control and adjustment of the electric furnace. Such changes may include, but are not limited to, sudden changes in the electrode position relative to the molten material due to the collapse of the molten material during the melting process.

[0057] More preferably, the method is designed to provide a method step for setting n operating characteristics such that each n operating characteristic is in a target course in a second time following a first time.

[0058] In this way, this method has the advantage that the n operating characteristics can follow the target course more quickly, enabling an increase in control and adjustment speed, and thus further improving the overall control and adjustment of the electric furnace.

[0059] More preferably, the method provides a method step for determining n actual operating characteristics supplied to at least one electrode by electrode positioning means and / or power supply means in a third time following a second time, wherein a method step of model predictive calculation of the target course of each of the n operating characteristics up to a planned period is designed to be performed such that the target course of each operating characteristic in the third time is equal to the actual operating characteristic in the third time.

[0060] In this way, the method has the advantage of further improving the overall control and adjustment of the electric furnace because the target courses of the n operating characteristics are continuously updated, and therefore sudden changes in conditions inside the electric furnace during the melting process are also taken into account. Furthermore, the target courses of the n operating characteristics are updated over a continuous period within the planned period, enabling an increase in the control and adjustment speed over a long period.

[0061] More preferably, the method is designed to provide a method step for setting n operating characteristics such that each n operating characteristic is in a target course in a fourth time following a third time in terms of time.

[0062] In this way, this method has the advantage that the n operating characteristics can follow the target course faster and over a continuous period of time within the planned period, enabling an increase in control and adjustment speed, and thus further improving the overall control and adjustment of the electric furnace.

[0063] More preferably, the method is designed such that at least one operating characteristic and / or at least one actual operating characteristic is voltage.

[0064] In this way, the method has the advantage of enabling instantaneous control and adjustment of the power supplied to at least one electrode.

[0065] The voltage may be a voltage applied to at least one electrode.

[0066] More preferably, the method is designed such that at least one operating characteristic and / or at least one actual operating characteristic is current.

[0067] In this way, the method has the advantage of enabling instantaneous control and adjustment of the power supplied to at least one electrode.

[0068] The current may be a current supplied to at least one electrode.

[0069] More preferably, the method is designed such that at least one operating characteristic and / or at least one actual operating characteristic is an electrical frequency.

[0070] In this way, the method has the advantage of increasing the power factor of the power flowing through at least one electrode by enabling instantaneous control and adjustment of the ratio of active power flow to reactive power flow supplied to at least one electrode.

[0071] The electrical frequency may be the electrical frequency applied to at least one electrode.

[0072] More preferably, the method is designed such that at least one operating characteristic and / or at least one actual operating characteristic is the electrode position of at least one electrode.

[0073] In this way, the method has the advantage of significantly reducing wear on at least one electrode.

[0074] The electrode position may be perpendicular to the molten material in the electric furnace.

[0075] More preferably, the method is designed such that the model prediction calculation of at least one target course for at least one operating characteristic is based on a discrete-time dynamic model of the melting process of the molten material in the electric furnace, and the time interval between two consecutive time processes is 0.1 seconds or less.

[0076] In this way, the method has the advantage of improving the accuracy of electric furnace control and adjustment, as it allows for the determination of at least one actual operating characteristic and the setting of at least one operating characteristic with higher sampling resolution.

[0077] Preferably, the time interval between two consecutive time steps in the time-dynamic model of the melting process of the molten material is 0.01 seconds or less, more preferably 0.001 seconds or less, and particularly preferably 0.0005 seconds or less. In this way, the method has the advantage that the accuracy of electric furnace control and adjustment is further improved because at least one actual characteristic can be determined and at least one operating characteristic can be set with even higher sampling resolution.

[0078] According to a preferred embodiment, the time interval between two consecutive time steps in the time-dynamic model of the melting process of the molten material is 0.0001 seconds or more, more preferably 0.0005 seconds or more, and particularly preferably 0.001 seconds or more.

[0079] According to a preferred embodiment, the time interval between two consecutive time steps in the time-dynamic model of the melting process of the molten material is in the time range of 0.0002 seconds to 0.1 seconds, preferably in the time range of 0.001 seconds to 0.1 seconds, and particularly preferably in the time range of 0.01 seconds to 0.1 seconds.

[0080] More preferably, this method is designed such that the result of the melting process to be achieved is selected from the group including the following: - Minimizing the electrical energy required to heat the molten material to a predetermined temperature, - Minimizing the time required to heat the molten material to a predetermined temperature, - Minimizing wear on at least one electrode used to heat the molten material to a predetermined temperature.

[0081] In this way, this method has the advantage of reducing the overall operating costs of the melting process using an electric furnace, while simultaneously extending the service life of the electric furnace.

[0082] In a preferred embodiment, the method is designed such that the result of the melting process to be achieved is selected from the group including the following: - To minimize and / or equalize wear on the refractory vessel of the electric furnace, - To minimize and / or equalize wear on electric furnace panels, - To minimize and / or equalize wear on the bottom shell of the refractory vessel of an electric furnace, - To minimize and / or equalize wear on the slag door of the electric furnace, - To minimize and / or equalize wear on the top lid of the electric furnace, - Optimizing the reheating of the raw material discharge zone and / or injection zone and / or molten metal outlet zone within the electric furnace vessel, particularly the eccentric bottom molten metal outlet zone, - Optimizing the reheating of the chemical additive material discharge zone and / or chemical additive material injection zone within the electric furnace vessel, - Optimizing the reheating of the slag door zone inside the electric furnace vessel, - To minimize harmonic distortion and / or flicker in the power supply network, - To maximize the ratio of active power flow to reactive power flow in the supply network.

[0083] Equalizing wear on specific parts of an electric furnace can be understood as ensuring that wear is substantially uniform across a given surface of a particular part of the electric furnace. In this way, the overall service life of the electric furnace can be extended.

[0084] The present invention is further based on the objective of providing an electric furnace in which the instantaneous fluctuations in power absorption by the electric furnace during the melting process of the molten material are reduced.

[0085] The underlying problem of this invention is solved by the electric furnace described in claim 17.

[0086] More specifically, the problem underlying the present invention is solved by an electric furnace for melting a material, the electric furnace comprising electrode positioning means for positioning at least one electrode of the electric furnace. The electric furnace further comprises power supply means for supplying power to the at least one electrode. Furthermore, the electric furnace comprises electronic control means for transmitting signals, which are data-coupled to the electrode positioning means and the power supply means. The electric furnace is characterized in that the electronic control means is adapted to adjust the operation of the electric furnace during the melting process of the material to be melted according to any of the methods described above. [Brief explanation of the drawing]

[0087] Further advantages, details, and characteristics of the present invention will be described in the following description of embodiments. [Figure 1] A flowchart of a first embodiment of a method for adjusting the operation of an electric furnace during the melting process of a molten material is shown. [Figure 2] A flowchart of a second embodiment of a method for adjusting the operation of an electric furnace during the melting process of a molten material is shown. [Figure 3] A diagram is shown illustrating the target course of the electric furnace's operating characteristics during the melting process over the planned period N, based on the desired results and the actual operating characteristics up to the first time t1. [Figure 4] A diagram is shown illustrating the target course of the electric furnace's operating characteristics during the melting process over the planned period N, based on the desired results and the actual operating characteristics up to the second time point t2. [Figure 5] A diagram is shown illustrating the target course of the electric furnace's operating characteristics during the melting process over the planned period N, based on the desired results and the actual operating characteristics up to the fourth time point t4. [Figure 6] A schematic diagram of an electric furnace for melting materials according to the first embodiment is shown.

[0088] In the following descriptions, the same reference number describes the same element and the same characteristic, and as a result, the description of one element that is executed by referring to one figure is also valid for other figures, and consequently, repetition of each characteristic is omitted. [Modes for carrying out the invention]

[0089] Figure 1 shows a flowchart of a first embodiment of a method for adjusting the operation of an electric furnace 10 during the melting process of a molten material. The electric furnace 10 shown in Figure 6 comprises an electrode positioning means 30 for positioning at least one electrode 40 of the electric furnace 10, a power supply means 50 for supplying power to the at least one electrode 40, and an electronic control means 60 for transmitting signals, which is data-coupled to the electrode positioning means 30 and the power supply means 50.

[0090] This method includes the following steps. -Step S1 involves model predicting and calculating the target course of at least one operating characteristic Op up to the planned period N, based on the desired outcome of the melting process. -Step S2 of setting at least one operating characteristic Op by the electrode positioning means 30 and / or power supply means 50 such that at least one operating characteristic Op is on a target course for at least one operating characteristic Op at a predetermined future point in time, -The step S3 includes determining at least one actual operating characteristic Oap supplied to at least one electrode 40 by the electrode positioning means 30 and / or power supply means 50 at a first time t1, The method step S1 of model prediction calculation of the target course of at least one operating characteristic Op up to the planned period N is performed such that the target course of at least one operating characteristic Op at a first time t1 is equal to the actual operating characteristic Oap at a first time t1.

[0091] This method further includes the following steps. -Step S4 of setting at least one operating characteristic Op such that at least one operating characteristic Op is on a target course in terms of time at a second time t2 following a first time t1, - A step S5 in which, at a third time t3, at least one actual operating characteristic Oap supplied to at least one electrode 40 by the electrode positioning means 30 and / or power supply means 50, the third time t3 is followed in time by step S5, The model prediction calculation S1 of the target course of at least one operating characteristic Op up to the planned period N is performed such that the target course of at least one operating characteristic Op at the third time t3 is equal to the actual operating characteristic Oap at the third time t3. - The process includes step S6 of setting at least one operating characteristic Op such that at least one operating characteristic Op is on a target course in a fourth time t4 following a third time t3.

[0092] Figure 2 shows a flowchart of a second embodiment of a method for adjusting the operation of the electric furnace 10 during the melting process of the molten material.

[0093] This method includes the following steps. -Step S7 involves model predictive calculation of the target course of n operating characteristics Op up to the planned period N, based on the desired outcome of the melting process. - Step S8: Setting n operating characteristics Op by the electrode positioning means 30 and / or power supply means 50 so that each of the n operating characteristics Op is located in the respective target course associated with each operating characteristic Op at a predetermined future point in time. -The step S9 includes determining n actual operating characteristics Oap supplied to at least one electrode 40 by the electrode positioning means 30 and / or power supply means 50 at a first time t1, Step S7 of the method for model predicting and calculating the target course of each of the n operating characteristics Op up to the planned period N is performed such that the target course of each operating characteristic Op at the first time t1 is equal to the actual operating characteristic Oap at the first time t1.

[0094] This method further includes the following steps. - A step S10 to set n operating characteristics Op such that each of the n operating characteristics Op is in its respective target course in a second time t2 following a first time t1, - A step S11n in which, at a third time t3, the actual operating characteristics Oap supplied to at least one electrode 40 by the electrode positioning means 30 and / or power supply means 50, wherein the third time t3 is followed in time by step S11n, The method step S7 of model prediction calculation of the target course of each of the n operating characteristics Op up to the planned period N is performed such that the target course of each operating characteristic Op at the third time t3 is equal to the actual operating characteristic Oap at the third time t3. -Includes step S12 of setting n operating characteristics Op such that each of the n operating characteristics Op is in its respective target course in a fourth time t4 following a third time t3.

[0095] Figure 3 shows a target course of the electric furnace's operating characteristics during the melting process over the planned period N, based on the desired results and the actual operating characteristics up to the first time t1.

[0096] In step S1 of the model prediction calculation method, the target course of at least one operating characteristic Op is calculated up to the planned period N. In step S2 of the method, the at least one operating characteristic Op is set by the electrode positioning means 30 and / or power supply means 50 such that at least one operating characteristic Op is on the target course of at least one operating characteristic Op at a predetermined future point in time. This is represented by the first "x" in the figure when we start counting the number of "x" from the left side of the figure.

[0097] At least one actual characteristic Oap supplied to at least one positioning means 30 and / or power supply means 50 at a first time t1 is determined in method step S3. Method step S1 of model prediction calculation of the target course of at least one operating characteristic Op up to the planned period N is performed such that the target course of at least one operating characteristic Op at the first time t1 is equal to the actual operating characteristic Oap at the first time t1. This is represented by the second "x" in the figure. As can be seen from the figure, the actual operating characteristic Oap and the target course Op of the operating characteristic coincide at the first time t1. In this way, the target course of the operating characteristic Op is continuously updated throughout the melting process of the molten material, taking into account the actual operating characteristic Oap. This results in more precise control and adjustment of the operating characteristics and thus improves the overall efficiency of the melting process.

[0098] Figure 4 shows a diagram of the target course of the electric furnace's operating characteristics during the melting process over the planned period N, based on the desired results and the actual operating characteristics up to the second time point t2.

[0099] At least one operating characteristic Op is set in method step S4 such that at least one operating characteristic Op is on a target course in time, at a second time t2 following a first time t1. This is represented by the third "x" in the figure.

[0100] Figure 5 shows the target course of the electric furnace's operating characteristics during the melting process over the planned period N, based on the desired results and the actual operating characteristics up to the fourth time t4.

[0101] In method step S5, at least one actual characteristic Oap supplied to at least one positioning means 30 and / or power supply means 50 in a third time t3 following a second time t2 is determined. Method step S1 of model prediction calculation of the target course of at least one operating characteristic Op up to the planned period N is performed such that the target course of at least one operating characteristic Op in the third time t3 is equal to the actual operating characteristic Oap in the third time t3. This is represented by the fourth "x" in the figure. As can be seen from the figure, the actual operating characteristic Oap and the target course of the operating characteristic Op coincide in the third time t3. In this way, the target course of the operating characteristic Op is continuously updated throughout the entire melting process of the molten material, taking into account the actual operating characteristic Oap.

[0102] In step S6 of the method, at least one operating characteristic Op is set to be on a target course in time at a fourth time t4 following a third time t3. This is represented by the fifth "x" in the figure.

[0103] Figure 6 shows a schematic diagram of an electric furnace 10 for melting a material in a first embodiment. The electric furnace 10 comprises two electrode positioning means 30 for positioning two electrodes 40 of the electric furnace 10. Each electrode positioning means 30 is connected to only one electrode 40, and each electrode 40 is connected to only one electrode positioning means 30. The electrodes 40 are positioned within a furnace vessel 70 containing the material to be molten. The electric furnace 10 further comprises a power supply means 50 for supplying power to the two electrodes 40. The power supply means 50 is connected to both electrodes 40. The electric furnace 10 further comprises an electronic control means 60, which is data-coupled to the two electrode positioning means 30 and the power supply means 50 to transmit signals. The electrode control means 60 is further adapted to adjust the operation of the electric furnace 10 during the melting process of the material to be molten, in accordance with the method for adjusting the operation of the electric furnace 10 during the melting process of the material to be molten, as described above. [Explanation of symbols]

[0104] 10 Electric furnace 30 Electrode positioning means 40 electrodes 50 Power supply means 60 Electronic control means 70 Furnace Vessel Op Operating Characteristics Oap Actual Operating Characteristics N Planning period Up Voltage Ip current Fp Electrical frequency t1 First time t2 Second time t3 Third time t4 The fourth time S1 Method step S1 S2 Method step S2 S3 Method step S3 S4 Method step S4 S5 Method step S5 S6 Method step S6 S7 Method step S7 S8 Method step S8 S9 Method step S9 S10 Method Engineering S10 S11 Method Engineering S11 S12 Method Engineering S12

Claims

1. A method for adjusting the operation of an electric furnace (10) during the melting process of a molten material, wherein the electric furnace (10) - An electrode positioning means (30) for positioning at least one electrode (40) of the electric furnace (10), - Power supply means (50) for supplying power to at least one electrode (40), - Includes an electronic control means (60) data-coupled to the electrode positioning means (30) and the power supply means (50) for transmitting signals, The above method involves the following steps: - A step (S1) of model predicting and calculating a target course for at least one operating characteristic (Op) up to the planned period (N) based on the results to be achieved in the melting process, A method comprising the step (S2) of setting the at least one operating characteristic (Op) by the electrode positioning means (30) and / or the power supply means (50) such that the at least one operating characteristic (Op) is on the target course of the at least one operating characteristic (Op) at a predetermined future point in time.

2. - The method includes a step (S3) for determining at least one actual operating characteristic (Oap) supplied to the at least one electrode (40) by the electrode positioning means (30) and / or the power supply means (50) at a first time (t1), The method according to claim 1, characterized in that the step of model predicting (S1) the target course of the at least one operating characteristic (Op) up to the planned target period (N) is performed such that the target course of the at least one operating characteristic (Op) at the first time (t1) is equal to the actual operating characteristic (Oap) at the first time (t1).

3. The above method involves the following steps: The method according to claim 2, characterized in that it includes a step (S4) of setting the at least one operating characteristic (Op) such that the at least one operating characteristic (Op) is in the target course in a second time (t2) following a first time (t1) with respect to time.

4. - The method includes a method step (S5) for determining at least one actual operating characteristic (Oap) supplied to the at least one electrode (40) by the electrode positioning means (30) and / or the power supply means (50) at a third time (t3), wherein the third time (t3) follows the second time (t2) in terms of time. The method according to claim 3, characterized in that the method step of the model prediction calculation (S1) of the target course of the at least one operating characteristic (Op) up to the planned target period (N) is performed such that the target course of the at least one operating characteristic (Op) at the third time (t3) is equal to the actual operating characteristic (Oap) at the third time (t3).

5. The above method involves the following steps: The method according to claim 4, characterized in that it includes a step (S6) of setting the at least one operating characteristic (Op) such that the at least one operating characteristic (Op) is in the target course in a fourth time (t4) following the third time (t3) with respect to time.

6. The following method steps, - A step (S7) in which, based on the results to be achieved in the melting process, a model predictive calculation is performed to determine the target course of n operational characteristics (Op) up to the planned period (N), The method according to any one of claims 1 to 5, characterized by: - ​​A step (S8) of setting the n operating characteristics (Op) by the electrode positioning means (30) and / or the power supply means (50) such that each of the n operating characteristics (Op) is located in the respective target course associated with each of the operating characteristics (Op) at a predetermined future point in time.

7. - The method includes a step (S9) of determining n actual operating characteristics (Oap) supplied to at least one electrode (40) by the electrode positioning means (30) and / or the power supply means (50) at a first time (t1), The method according to claim 6, characterized in that the step of model predicting (S7) the target course of each of the n operating characteristics (Op) up to the planned target period (N) is performed such that the target course of each of the operating characteristics (Op) at the first time (t1) is equal to the actual operating characteristics (Oap) at the first time (t1).

8. The above method involves the following steps: The method according to claim 7, characterized in that it includes a step (S10) of setting the n operating characteristics (Op) such that each of the n operating characteristics (Op) is in the respective target course in a second time (t2) following the first time (t1) with respect to time.

9. - The method provides a method step (S11) for determining n actual operating characteristics (Oap) supplied to at least one electrode (40) by the electrode positioning means (30) and / or the power supply means (50) at a third time (t3), wherein the third time (t3) follows the second time (t2) in terms of time. The method according to claim 8, characterized in that the method step of the model prediction calculation (S7) of the target course of each of the n operating characteristics (Op) up to the planned target period (N) is performed such that the target course of each of the operating characteristics (Op) at the third time (t3) is equal to the actual operating characteristics (Oap) at the third time (t3).

10. The above method involves the following steps: The method according to claim 9, characterized in that it includes a step (S12) of setting the n operating characteristics (Op) such that in a fourth time (t4) following a third time (t3) with respect to time, each of the n operating characteristics (Op) is in the respective target course.

11. The method according to any one of claims 1 to 10, characterized in that at least one operating characteristic (Op) and / or at least one actual operating characteristic (Oap) is voltage (Up).

12. The method according to any one of claims 1 to 11, characterized in that at least one operating characteristic (Op) and / or at least one actual operating characteristic (Oap) is an electric current (Ip).

13. The method according to any one of claims 1 to 12, characterized in that at least one operating characteristic (Op) and / or at least one actual operating characteristic (Oap) is an electrical frequency (Fp).

14. The method according to any one of claims 1 to 13, characterized in that at least one operating characteristic (Op) and / or at least one actual operating characteristic (Oap) is the electrode position of the at least one electrode (40).

15. The method according to any one of claims 1 to 14, characterized in that the model prediction calculation of the at least one target course of the at least one operating characteristic (Op) is based on a discrete-time dynamic model of the melting process of the molten material in the electric furnace (10), and the time interval between two consecutive time steps is 0.1 seconds or less.

16. The result of the melting process to be achieved is selected from the group including the following: - To minimize the electrical energy required to heat the molten material to a predetermined temperature, - To minimize the time required to heat the molten material to a predetermined temperature, The method according to any one of claims 1 to 15, characterized by comprising minimizing wear of the at least one electrode (40) for heating the molten material to a predetermined temperature.

17. An electric furnace (10) for melting materials, wherein the electric furnace (10) - An electrode positioning means (30) for positioning at least one electrode (40) of the electric furnace (10), - Power supply means (50) for supplying power to at least one electrode (40), - Includes an electronic control means (60) data-coupled to the electrode positioning means (30) and the power supply means (50) for transmitting signals, The electric furnace (10) is characterized in that the electronic control means (60) is adapted to adjust the operation of the electric furnace (10) during the melting process of the molten material described in any one of claims 1 to 16.

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