How to get a plant network running

Abstract

A method for operating a plant network (1) including a direct reduction plant (2) equipped with a port (2') and an electric melting furnace (3) is described. In this method, product characteristics are measured by a sensor (4), and the degree of metallization of sponge iron in the direct reduction plant (2) is adjusted accordingly. To implement this method, a control device (5) can be used to control a flow valve (8) by a corresponding quantity (7) through inference shown in reference number (6), for example, and the degree of metallization can be changed by adjusting the flow rate of the reducing gas.

Description

[Technical Field]

[0001] The present invention relates to a method for operating a plant network, wherein the plant network comprises a direct reduction plant and an electromelting furnace located downstream of the direct reduction plant. [Background technology]

[0002] In efforts to reduce CO2 emissions associated with steelmaking, steel production via the so-called electric arc furnace route is attracting significant attention. In the electric arc furnace route, partially reduced direct reduced iron (sponge iron) and / or scrap are used as starting materials. These starting materials are melted in an electrically driven furnace, such as an electric arc furnace (EAF), and, if necessary, oxygen-affinity components are removed in a further step by blowing in oxygen. First, sponge iron is produced in a direct reduction plant. Here, sponge iron production is based on the principle of reducing iron ore by exposing it to a reducing gas. This reduces and decomposes Fe compounds, particularly Fe-O compounds, contained in the iron ore, leaving metallic iron as a result of this metallization. Sponge iron has a degree of metallization of MG. DRA It then exits directly from the reduction plant. Here, the degree of metallization is determined by the mass of iron present (Fe). 元素 The total mass of iron in existence Fe 総量 It is defined as the quotient of [the specified number].

[0003] In the initial direct reduction step, the largest proportion of iron in the iron ore is metallized, typically a percentage called the degree of metallization (MG). DRA Regarding this, it far exceeds 80 percent of the atoms present. The degree of metallization refers to the weight ratio of metallic iron to the total amount of iron, expressed as a percentage. This is the percentage of Fe atoms present in metallic form in sponge iron extracted after passing through a direct reduction plant. DRA This means that it contains the proportion of Fe atoms in the metallic form MG. DRA And the proportion of Fe atoms in the bonded form 1-MG DRASponge iron containing the above is charged into the melting furnace. Therefore, Fe atoms that have not yet been metallized during direct reduction are mostly metallized in the subsequent melting process, especially under the addition of a carbon carrier, and the metallization degree MG 生成物 is metallized up to. The metallization degree MG 生成物 is 100 percent, or slightly less than 100 percent, up to 2 percent less. This means that the iron contained in the whole consisting of the molten metal and the produced slag is at least almost completely metallized.

Summary of the Invention

Problems to be Solved by the Invention

[0004] From the above description, it can be immediately understood that the ratio of the metallization process in the direct reduction plant and the ratio of the metallization process in the melting furnace are directly related to each other. Based on this, an object of the present invention is to provide an improvement in the operation of a plant network consisting of a direct reduction plant and a melting furnace.

Means for Solving the Problems

[0005] The present invention is solved by a method having the features of claim 1.

[0006] A method of operating a plant network is provided. The plant network includes at least one direct reduction plant, that is, one direct reduction plant, or two or more, for example, two direct reduction plants, and an electric melting furnace arranged downstream of the direct reduction plant.

[0007] This method can be designed, for example, as a method for producing pig iron.

[0008] In other words, the essential idea of ​​the presented invention is that the operation of the plant network is considered as a whole, and the plant network comprises both a melting furnace and a direct reduction plant. For the coordinated operation of the plant network, its components, in particular the direct reduction plant and the melting furnace, are coupled to one another via a common control device, such as a control room. [Brief explanation of the drawing]

[0009] [Figure 1] a) The curve shown represents the first plant-specific characteristic curve value DRA-MGDRA of the direct reduction plant. b) The curve shown represents the second plant-specific characteristic curve value melting furnace-MG product of the melting furnace. c) shows the theoretical value of a predetermined degree of metallization MGDRA. [Figure 2] This is a schematic diagram of an exemplary embodiment of a method for operating a plant network 1 comprising a direct reduction plant 2 and an electromelting furnace 3 located downstream of the direct reduction plant 2, according to the present invention. [Modes for carrying out the invention]

[0010] The concept of a dissolution furnace located downstream of the direct reduction plant means that in the method sequence, the dissolution furnace is immediately after the direct reduction plant. That is, the product produced in the direct reduction plant is transported to and / or temporarily stored in the dissolution furnace, but no washing or other additional processing is performed on the product produced in the direct reduction plant.

[0011] A direct reduction plant is a plant in which a solid reaction occurs in which oxygen is removed from iron ore. Reducing agents used in this process include, for example, coal or natural gas, or atomic or molecular hydrogen, which have seen increased use in recent years and are expected to see increased use in the future. The reaction takes place at a temperature below the melting point of the iron ore, and therefore its external form remains largely unchanged.

[0012] A direct reduction plant can be designed, for example, as a shaft furnace with a reduction zone through which iron ore is passed in the opposite direction to the reducing gas flow. In an alternative embodiment, the direct reduction plant can also be designed, for example, as a rotary cylindrical furnace through which iron ore is transported in the opposite direction to the reducing gas flow. Direct reduction plants themselves are well known in practice.

[0013] An electric melting furnace, also referred to as an electric heating device for melting metals or heating liquid metals, may be, for example, an electric arc furnace (EAF) having direct arc action, where an arc is generated between an electrode and the metal. Possible forms include alternating current arc melting furnaces (EAFac), direct current arc melting furnaces (EAFdc), and ladle furnaces (LF).

[0014] According to the present invention, an electrically driven melting furnace is used. Here, all types of electrically driven melting furnaces are conceivable, but a preferred option is an arc-resistance heated melting furnace. Such a melting furnace operates on the principle of generating an arc between an electrode and the charge, heating the charge or slag, particularly by the Joule effect. An arc-resistance heated melting furnace can be designed, for example, as a submerged electric arc furnace (SAF), AC arc reducer (SAFac), or DC arc reducer (SAFdc), where the electrode is immersed in the charge or slag. Another form is a furnace in which the electrode terminates just above the slag. In this type of furnace, the slag is not shielded by the charge, at least in the area of ​​the electrode. Thus, the slag is open to the top, and the brush arc generated in the slag can be seen from above. This type of furnace is called an open slag bath furnace (OSBF).

[0015] Particularly preferably, in the method according to the present invention, the melting furnace is designed as a submerged electric arc furnace (SAF).

[0016] Alternatively, and more preferably, in the method according to the present invention, the melting furnace is designed as an open slag bath furnace (OSBF).

[0017] In the method according to the present invention, iron ore passes through a direct reduction plant during the continuous operation of the plant network. Upon passing through the direct reduction plant, the iron ore is reduced to sponge iron by reducing gas, particularly molecular hydrogen and / or natural gas. Depending on process control and process parameters, such as the residence time of the iron ore in the direct reduction plant and the flow rate of the reducing gas, the iron ore undergoes a metallization process (MG). DRA It is converted to sponge iron. Degree of metallization MG DRA This is the discharge point of sponge iron from the direct reduction plant, where it is more than 80 percent, preferably more than 90 percent, and particularly preferably more than 95 percent. After leaving the direct reduction plant, metallized MG DRA Sponge iron containing [the specified material] is fed into a melting furnace.

[0018] In the melting furnace, the melting of sponge iron is carried out by adding a carbon carrier, and optionally with the addition of further iron-containing materials such as scrap, and / or additives to adjust the resulting slag, resulting in a product with a degree of metallization of MG. 生成物 A molten metal bath is produced, consisting of molten metal containing and slag floating on the molten metal. The properties of the slag are preferably intentionally influenced by additives such as lime, sand, and / or bauxite.

[0019] In a discrete process, the molten metal is extracted. That is, the molten metal is discharged from the melting furnace and placed into a portable collection container pre-positioned at a predetermined collection location. For example, a discharge opening on the lower or side wall of the melting furnace can be appropriately opened for an extended period of time, and thus the molten metal flows out from there. Below the discharge opening, a collection container designed, for example, as a so-called collection ladle can be placed. For example, a collection ladle can be provided as a component of a ladle transport vehicle known to those skilled in the art.

[0020] According to the present invention, the product characteristics of products produced in a plant network are intended to be measured continuously or semi-continuously by sensors.

[0021] Quasi-continuous measurement of product properties means measurement of product properties repeated at predetermined time intervals, particularly at predetermined short time intervals. For example, this can represent measurement of product properties repeated periodically at short time intervals, where the time interval is constant, for example, between 1 minute and 60 minutes, preferably between 1 minute and 5 minutes, between two directly consecutive measurements of product properties. Alternatively, this can represent measurement of product properties repeated aperiodically at short time intervals, where the time interval is not constant, for example, between 1 minute and 60 minutes, preferably between 1 minute and 5 minutes, between two directly consecutive measurements of product properties.

[0022] Based on the presence of measured product properties, according to the present invention, a predetermined degree of metallization MG is determined according to the measured product properties. DRA,理論値 Further changes will be made to the operation of the plant network to adjust for the metallization of sponge iron after it has passed through the direct reduction plant. DRA,理論値 It will be modified to match.

[0023] Therefore, the present invention relates to the reduction process that can occur throughout the plant network during the production of molten metal, particularly pig iron, i.e., the degree of metallization of the product MG. 生成物 The fundamental idea is to deliberately distribute the total amount of chemical-physical processes that can be used in whole to obtain a molten metal with a specific metal content (MG) between two central plants in the plant network: one being the direct reduction plant and the other the melting furnace. The distribution of reduction work between the two basic processes in the plant network is controlled by a single parameter to be adjusted, controlled, or regulated, namely the degree of metallization (MG). DRABased on this, there is the advantage of being able to intentionally coordinate the overall process to conform to the currently dominant framework conditions. Furthermore, a major advantage of this method is that a large number of physical quantities that can be directly measured at the plant are related to the degree of metallization (MG). DRA It is directly related to the degree of metallization (MG). DRA Once corresponding plant-specific empirical data is obtained for this association between each physical quantity, this can be used to determine the degree of metallization (MG) that meets the requirements. DRA It can be directly converted to the desired changes.

[0024] This intended distribution of reduction work between the process carried out in a direct reduction plant on the one hand and the process carried out in a melting furnace on the other hand is a predetermined degree of metallization MG DRA,理論値 This is achieved in concrete implementation by adjusting the degree of metallization of sponge iron when it comes out of the direct reduction plant. DRA The predetermined degree of metallization MG DRA,理論値 If this matches, the operation of the plant network will continue without change, but the degree of metallization MG DRA The predetermined degree of metallization MG DRA,理論値 If it deviates from the standard, the operation of the plant network will be affected by the degree of metallization (MG). DRA The target value is MG DRA,理論値 It will be modified to change toward that.

[0025] Modifications to the operation of the plant network to adjust to a predetermined degree of metallization are made based on product characteristic values ​​of the products produced in the plant network, which are continuously or semi-continuously measured by sensors. This is done based on the degree of metallization MG produced in the plant network. DRA Products having a correlation with the product are inspected by a sensor, and then, based on the obtained sensor results, the product and the degree of metallization (MG) are determined. DRA Correlation with, in particular, product properties and degree of metallization (MG) DRA The correlation with this means that it is possible to determine whether the plant network operation can be continued without modification, or whether modification of the plant network operation is necessary. (Product and degree of metallization MG)DRA The correlation with is preferably the injective function "metallicity MG DRA →Product properties are "product properties", and particularly preferably a bijective function "degree of metallization MG DRA →Product properties. For example, product properties and degree of metallization MG DRA The correlation between these two factors may be an empirically discoverable relationship. Those skilled in the art can easily discover this empirically discoverable relationship based on a simple series of tests.

[0026] For example, starting from the measured product properties, the degree of metallization MG is determined empirically beforehand. DRA Based on the existing correspondence between the product properties and the degree of metallization, the degree of metallization MG is determined continuously or semi-continuously. DRA It may be intended that the degree of metallization MG be determined. DRA The quasi-continuous determination of the degree of metallization MG is repeated at predetermined time intervals, particularly at predetermined short time intervals. DRA This means the determination of the degree of metallization MG, which is periodically repeated at short time intervals. DRA This represents the determination, with a constant time interval, for example, two direct consecutive metallization degrees MG DRA The interval between the determinations may be, for example, between 1 and 60 minutes, preferably between 1 and 5 minutes. Alternatively, this may be, for example, a non-periodic repeating of the degree of metallization MG at short time intervals. DRA It can also represent the determination of the degree of metallization (MG), and the time interval is not constant, for example, two direct consecutive determinations of the degree of metallization (MG). DRA Between the determinations, the values ​​can be, for example, between 1 minute and 60 minutes, preferably between 1 minute and 5 minutes.

[0027] This is determined empirically and, therefore based on known data, from the measured product properties to the degree of metallization MG DRA This means that the following is derived. Next, the degree of metallization is set to a predetermined degree of metallization MG DRA,理論値 It can be compared with a predetermined degree of metallization MG DRA,理論値 Degree of metallization from MG DRA If a deviation is confirmed, the predetermined degree of metallization MG DRA,理論値 You can start making changes to the operation of the plant network to make adjustments.

[0028] In particular, a predetermined degree of metallization MG DRA,理論値 Degree of metallization from MG DRA If a deviation is confirmed and the amount of that deviation is greater than the minimum deviation, the predetermined degree of metallization MG DRA,理論値 Modifications to the operation of the plant network to adjust for this may be initiated, which is intended to bring the benefit of greater process stability.

[0029] The evaluation of the degree of metallization based on empirical data, comparison with a predetermined degree of metallization, and, if necessary, initiation of changes in the operation of the plant network, can be controlled, for example, by a control device for the plant network, which is coupled with a direct reduction plant, a melting furnace, and sensors.

[0030] The specified degree of metallization MG DRA,理論値 For example, to adjust the degree of metallization to the degree of metallization MG, change the operation of the plant network, empirically determined DRA The correspondence between the product properties and a given degree of metallization can be relied upon, and based on this, adjustments to the operation of the plant network are made, preferably by control, and particularly preferably by adjustment. This means that the required changes to the product properties are derived according to the degree of deviation of the degree of metallization from a given degree of metallization. That is, the degree of the required changes to the product properties is measured, and therefore, changes to the operation of the plant network based on a known deviation of the degree of metallization result in changes to the operation of the plant network with the objective of making the desired changes to the product properties.

[0031] In short, changes to the operation of the plant network are made based on the measured product characteristics and one or two further aspects. 1. Empirically determined measured product properties and degree of metallization MG DRA The relationship, and 2. Based on the knowledge possessed by a person skilled in the art or knowledge obtained through empirical discovery, the degree of metallization MG DRA The degree of metallization is MG DRA,理論値To change to, or equivalently, MG DRA Product properties that depend on MG DRA,理論値 The operation of the plant network can be modified to change the product characteristics that depend on the plant.

[0032] To achieve this, it is sufficient to run the corresponding plant parameters just once, and the necessary empirical data can be obtained through normal procedures without conducting excessive experiments.

[0033] As an alternative to the empirical findings in 2., control or regulation may also be attempted.

[0034] In a favorable developmental form, the properties measured in the product produced in the direct reduction plant can be used as the product properties.

[0035] For example, the product properties are as follows: -As the volumetric flow rate of H2 in blast furnace gas (in this case, for example, an H2 sensor can be used as the sensor); or -As the volumetric flow rate ratio of H2 / H2O in blast furnace gas (in this case, for example, an H2 sensor can be used as the sensor and an H2O sensor can be used as a further sensor); or -As the volumetric flow rate of CO in blast furnace gas (in this case, for example, a CO sensor can be used as the sensor); or -As the volumetric flow rate ratio of CO / CO2 in blast furnace gas (in this case, for example, a CO sensor can be used as the sensor and a CO2 sensor can be used as a further sensor); or -As the degree of metallization of sponge iron measured directly, or - As an oxygen mass balance from "oxygen in the gas being introduced" to "oxygen in the blast furnace gas", or - As for the discharge temperature of sponge iron, It can be designed.

[0036] Alternatively, the properties measured in the product produced in the melting furnace can be used as product properties.

[0037] In this case, the product properties are, for example, as follows: -As the CO content in the exhaust gas of the melting furnace (in this case, for example, a CO sensor can be used as the sensor); or -As the volumetric flow rate ratio of CO / CO2 in the melting furnace exhaust gas (in this case, for example, a CO sensor can be used as the sensor and a CO2 sensor can be used as a further sensor); or -As the temperature of the molten metal when a certain amount of energy is input (in this case, for example, a thermometer can be used as a sensor); or -As oxygen activity in molten metal, or -As oxygen activity in slag, or -As total oxygen activity in molten metal and slag, or - As slag characteristics, in particular as the discharge coefficient or viscosity or CaO content or SiO2 content or the CaO and SiO2 content, -As an elemental component of pig iron, or -As a specific amount of slag, It can be designed.

[0038] The above examples concerning product properties share the common advantage of being physical parameters that can be directly measured by appropriate sensors; therefore, the sensors are designed, for example, to sense the directly measurable physical parameters.

[0039] For example, the sensor is a CO sensor, and the product characteristics could be the CO content in the melting furnace exhaust gas, or the volumetric flow rate ratio of CO / CO2 in the melting furnace exhaust gas.

[0040] For example, carbon monoxide, or CO, is produced, and its proportion in the exhaust gas of the melting furnace is the degree of metallization of sponge iron (MG). DRA Therefore, the degree of metallization depends on the oxygen that still reaches the melting furnace, DRAThe preferred total injection dependence of the CO content in the melting furnace exhaust gas can be empirically determined; if such empirical determination is made plant-specific, the degree of metallization MG can be empirically determined. DRA Based on the correspondence between the product properties and the degree of metallization, DRA This can then be determined. Next, this determined metallization level MG DRA From, the predetermined degree of metallization MG DRA,理論値 A comparison can be made, and depending on the result of this comparison, a predetermined degree of metallization MG can be determined. DRA,理論値 You can then begin modifying the operation of the plant network to replicate the results.

[0041] Naturally, when a person skilled in the art carries out development, they must consider the flow of material through the direct reduction plant and melting furnace, as well as any additional waiting time that may occur when implementing changes in the operation of the plant network (depending on the type of sensor used), when evaluating the product properties. This does not affect the functionality of the methods and their evolved forms described above, but results in differences in the inertia of process control depending on the type of implementation, for example, in the case of implementation as adjustment, it becomes a problem of the inertia of the adjustment loop. Therefore, the selection of appropriate product properties and the sensor mechanism for measuring them must be made by a person skilled in the art, and may be made, for example, from an economic standpoint, or considering the requirements for the inertia of change, control, or adjustment.

[0042] The specified degree of metallization MG DRA,理論値 For example, the characteristic curve characteristic value t of the first plant-specific characteristic value of a direct reduction plant, which was determined empirically. DRA -MG DRA , in other words, the value MG DRA characteristic values ​​corresponding to DRA Based on and empirically determined second plant-specific characteristic curve characteristics of the melting furnace 溶融炉 -MG 生成物 , in other words, the value MG 生成物 characteristic values ​​corresponding to 溶融炉 It may be measured based on the following. For example, a plant-specific characteristic curve may have the following characteristic values: - A measure relating to the weight of metallized iron per unit time, or - A measure relating to a specific amount of energy conversion, or - A measure relating to specific CO2 emissions, or - A measure of specific total costs It may include.

[0043] When referring to specific values ​​in the previous paragraph, these should preferably be understood as relating to the tonnage of pig iron produced. In this case, the above characteristic values ​​are characteristic values ​​with respect to direct reduction plants. DRA Regarding melting furnaces, characteristic values 溶融炉 These are applied accordingly.

[0044] Therefore, characteristic values ​​are, for example, characteristic values DRA And here, characteristic value DRA The degree of metallization is MG DRA A measure of the specific CO2 emissions of a direct reduction plant, which depends on the characteristics of that plant. 溶融炉 And here, characteristic value 溶融炉 The degree of metallization is MG 生成物 This could be a measure of the specific CO2 emissions of a melting furnace, depending on the situation.

[0045] In a special embodiment, a predetermined degree of metallization MG DRA,理論値 Min[characteristic value] DRA (MG DRA ) + characteristic value 溶融炉 (1-MG DRA The degree of metallization that satisfies the following condition is defined, and here the symbol "Min" indicates the determination of the minimum value. This is, firstly, simply MG 生成物 = 1 - MG DRAwhich means it is assumed. This is often a sufficiently accurate estimate in practical operation. Because, after passing through both the direct reduction plant and the melting furnace, the proportion of iron that has not yet been metallized is typically well below 5 percent, mostly below 2 percent, and usually about 1 percent, and most of this unmetallized iron is a component of the slag. Second, this means that the above-described method for changing the operation of the plant network is based on the determination of the deviation from the target value MG DRA,理論値 of the degree of metallization MG DRA from, where the target value is determined based on two plant-specific characteristic curves, each of the two characteristic curves depending on the degree of metallization of iron, and the characteristic value can be, for example, one of the above values. Then, the determination of the target value MG DRA,理論値 is made by determining the minimum value of the sum of the two characteristic curves, as given above as an equation. Of course, the term characteristic curve does not necessarily imply that the characteristic curve must exist as a closed analytical function. Each of the two characteristic curves can be, for example, a list of points in a two-dimensional space, and here, the search for the minimum value does not necessarily have to be done analytically and can also be done numerically. This is of course feasible without problem for those skilled in the art.

[0046] Thus, for example, if the characteristic value is a measure related to a specific CO2 emission, by the above-described implementation with the corresponding selection based on the characteristic value, the CO2 emission of the plant network is reduced by the distribution of the reduction operation between the direct reduction plant and the melting furnace. DRA,理論値 When, during the evaluation of the measured product characteristics, it is necessary to increase the degree of metallization MG

[0047] to achieve the target degree of metallization MG DRA,理論値 of the sponge iron, that is, when it is found that a part of the reduction operation should be transferred from the melting furnace to the direct reduction plant, the change in operation to adjust to increase the degree of metallization MG DRA DRA is, for example, the following: - an increase in the flow rate of reducing gas in the direct reduction plant, and / or - an extension of the residence time of iron ore or iron ore carrier to become sponge iron in the direct reduction plant, - an increase in the gas temperature of the reducing gas within the range of 560 to 1150 °C, preferably 900 to 1150 °C, is included.

[0048] MG DRA,理論値 towards the metallization degree MG DRA The degree to which this operation change is made to increase can be measured by direct control or regulation. Alternatively, in the operation change for adjusting to increase the metallization degree MG DRA,理論値 towards MG DRA the corresponding measure dependence for the operation change to the product characteristics, which is empirically determined in advance, to the metallization degree MG DRA or indirectly to the metallization degree MG DRA can be taken into account.

[0049] When evaluating the measured product characteristics, if it is necessary to reduce the metallization degree MG DRA,理論値 to achieve the target metallization degree MG of sponge iron DRA that is, if it is found that a part of the reduction operation from the direct reduction plant to the melting furnace should be carried out, the operation change of the plant network for adjusting to reduce the metallization degree MG DRA is, for example, the following: - a decrease in the flow rate of reducing gas in the direct reduction plant, and / or - a shortening of the residence time of iron ore to become sponge iron in the direct reduction plant, is included.

[0050] MG set as a decrease DRA,理論値 towards the metallization degree MG DRA The degree to which this operation change is made to decrease can be measured by direct control or regulation. Alternatively, towards MG DRA,理論値 towards the metallization degree MG DRAIn adjusting the operation to reduce the metallization degree MG, the degree of metallization MG was determined empirically in advance. DRA The degree of metallization MG DRA The dependence of corresponding measures for operational changes on product characteristics, which are a measure related to product properties, can be taken into consideration.

[0051] Therefore, the shift of reduction operations from a direct reduction plant to a melting furnace mirrorly results in a decrease in reduction operations at the direct reduction plant and an increase in reduction operations at the melting furnace, or vice versa.

[0052] Figures 1 and 2, shown as examples, are schematic diagrams illustrating exemplary embodiments of the method according to the present invention.

[0053] Figures 1a) to 1c schematically show the basic starting point of the method according to the present invention. In Figures 1a) and 1b), the empirically determined plant-specific characteristic curves can be seen, respectively. The curve shown in Figure 1a) is the first plant-specific characteristic curve characteristic value of a direct reduction plant. DRA -MG DRA The curve shown in Figure 1b) represents the second plant-specific characteristic curve of the melting furnace, and the characteristic values ​​are as follows: 溶融炉 -MG 生成物 This represents the correspondence of specific CO2 emissions expressed, for example, as kilograms / (tonnage of pig iron produced), i.e., a measure of specific CO2 emissions for each plant according to the degree of metallization. The characteristic values ​​are plant-specific and were obtained empirically, for example, through corresponding commissioning or data obtained during normal operation. From two characteristic value curves, a given degree of metallization MG DRA,理論値 However, it is determined, for example, based on measurement, where a predetermined degree of metallization MG DRA,理論値 These are the characteristic values ​​to be considered, as shown in Figure 1c). DRA (MG DRA ) and the characteristic values ​​that are considered 溶融炉 (1-MG DRA The degree of metallization is determined such that the sum curve from ) is minimized.

[0054] The specified degree of metallization MG DRA,理論値 Once established, this can be used to distribute all reduction operations performed within the plant network for the metallization of iron contained in iron ore when the plant network is operational.

[0055] In the schematic diagram of Figure 2, an exemplary embodiment of a method for operating a plant network 1 according to the present invention, comprising a direct reduction plant 2 and an electromelting furnace 3 located downstream of the direct reduction plant 2, can be seen. In continuous operation of the plant network 1, iron ore or iron ore carriers pass through the direct reduction plant 2, where they are reduced by reducing gases, particularly molecular hydrogen and / or natural gas, to sponge iron, which has a metallization degree of MG. DRA The molten metal exits through port 2' and is then fed into the melting furnace 3. Inside the melting furnace, the sponge iron is melted with the addition of a carbon carrier, such as coal and / or coke, and further components are optionally added to the molten metal. Such further components may be, for example, iron-containing materials such as scrap, or additives to adjust the composition of the resulting slag. The molten metal produced in the melting furnace 3, together with the resulting slag, has a product metallization degree of, for example, more than 98 percent, and can be removed from the melting furnace 3 by tapping the molten metal in a discontinuous process.

[0056] The product characteristics, set as the CO content in the melting bath exhaust gas, are measured by the CO sensor 4 continuously or semi-continuously, i.e., repeatedly at short intervals (e.g., time intervals of 1 to 60 minutes). Thus, in this example, the product characteristics of the products, more precisely the by-products, produced in the melting furnace 3 of the plant network 1 are considered. The detection and evaluation of these product characteristics, i.e., the CO content in the melting furnace exhaust gas, preferably the CO / CO2 volume flow rate ratio, are performed by the control device 5, which may be, for example, a control room or a control unit coupled to the control room.

[0057] The measured product properties are used repeatedly, starting from the measured product properties, continuously or semi-continuously, i.e., at short intervals (e.g., time intervals between 1 and 60 minutes), and the degree of metallization (MG) is linked to the measured product properties at the current time or a back-projected time. DRA Determine the degree of metallization (see reference number 6). DRA The decision was based on existing empirical data, namely, the empirically determined degree of metallization MG. DRA This is done based on the correspondence between the product properties and the product properties. Naturally, the time required for the direct transport of sponge iron within the reduction plant 2 and from there to the melting furnace 3, and for the influence of product properties there, such as the CO content, is taken into consideration by those skilled in the art who actually practice the invention, particularly as adjustment or control or regulation inertia, depending on the product properties being considered. For example, the degree of metallization MG performed as described above. DRA After the decision, it is the specified degree of metallization MG DRA,理論値 It is compared to the degree of metallization MG. DRA and the predetermined degree of metallization MG DRA,理論値 The deviation ΔMG DRA If it is found that there is a metallization degree MG, for example, the control device 5 will determine the degree of metallization MG DRA The predetermined degree of metallization MG DRA,理論値 A change in the operation of plant network 1 is initiated to adjust to the following: Thus, depending on the measured product characteristics, a predetermined degree of metallization MG is set. DRA,理論値 The operation of Plant Network 1 will be modified to accommodate the changes.

[0058] The specified degree of metallization MG DRA,理論値 Towards the degree of metallization MG DRA When changing the degree of metallization MG, the control device 5 uses the empirically determined degree of metallization MG. DRA Refer to the correspondence quantity 7 for the product properties, and the known difference ΔMG DRA =MG DRA,理論値 -MG DRA Based on this, the extent to which operational changes should be made is derived by comparing it with this corresponding quantity. For example, as in this example, the degree of metallization MG DRA The degree of metallization MG is set as an increase.DRA If it is determined that a change is necessary, for example, the degree of metallization MG DRA The change in operation of plant network 1 to increase the metallization degree MG can be achieved by increasing the flow rate of the reducing gas in the direct reduction plant 2, which is done by having the control device control the flow valve 8. As an alternative or additional measure, the time that the iron ore to be reduced to sponge iron remains in the direct reduction plant 2 can be extended, in which case the required degree of effect of the change in operation on the product properties for each of the two measures, or both measures combined, i.e., a quantitative measure of the change in CO content in the melting furnace 3 due to the required increase in the flow rate of the reducing gas in the direct reduction plant, and / or the extension of the time that the iron ore to be reduced to sponge iron remains in the direct reduction plant 2, can be obtained from previously stored quantitative data, which is the empirically determined degree of metallization MG already described above. DRA This is an example of a correspondence quantity between product characteristics and other factors. The degree to which operational changes are made to the product characteristics themselves can be selected by adjustment, control, or adjustment based on empirical values, i.e., empirically stored secondary control data.

Claims

1. A method for operating a plant network (1) including at least one direct reduction plant (2) and an electromelting furnace (3) located downstream of the direct reduction plant (2), During the continuous operation of the aforementioned plant network (1), The iron ore passes through the direct reduction plant (2), and during its passage through the direct reduction plant (2), the iron ore is subjected to a reduction gas, particularly molecular hydrogen and / or natural gas and / or other liquid or gaseous hydrocarbon compounds, which reduces the degree of metallization MG DRA It is reduced to sponge iron, and after passing through the above, the degree of metallization MG DRA The sponge iron having the above is fed into the melting furnace (3), In the melting furnace (3), the sponge iron is melted by adding a carbon carrier and optionally adding further iron-containing material such as scrap, and the metallization degree of the product is MG 生成物 A molten metal bath is generated consisting of molten metal having and slag floating on the molten metal, and in a discontinuous process, the molten metal is removed from the melting furnace (3) by tapping the molten metal. The product characteristics of the products produced in the plant network (1) are measured continuously or semi-continuously by a sensor (4). Depending on the measured product characteristics, the predetermined target value MG of the degree of metallization DRA,理論値 The degree of metallization MG DRA To make adjustments, the operation of the plant network (1) is modified. method.

2. Starting from the measured product characteristics, the degree of metallization MG determined empirically DRA Based on the correspondence of the product characteristics to the degree of metallization MG DRA is determined continuously or quasi - continuously, and when a deviation of the degree of metallization MG DRA,理論値 from the predetermined degree of metallization MG DRA is confirmed, for adjustment to the predetermined degree of metallization MG DRA,理論値 the change in the operation of the plant network is made The method according to claim 1.

3. The predetermined degree of metallization MG DRA,理論値 The changes to the operation of the plant network (1) for adjustment to the degree of metallization MG are determined empirically. DRA It is modified, preferably controlled, and particularly preferably adjusted based on the correspondence quantity of the product properties to the given value. The method according to claim 1 or claim 2.

4. The product characteristics of the product produced in the direct reduction plant (2) are measured. The method according to any one of claims 1 to 3.

5. The aforementioned product characteristics are, H in blast furnace gas 2 It is a volumetric flow rate, or H in blast furnace gas 2 / H 2 It is the volumetric flow rate ratio of O, or The volumetric flow rate of CO in blast furnace gas, or CO / CO2 in blast furnace gas 2 It is the volumetric flow rate ratio, or The degree of metallization of the sponge iron measured directly, or This refers to the oxygen mass balance from "oxygen in the gas being introduced" to "oxygen in the blast furnace gas," or The discharge temperature of the aforementioned sponge iron is The method according to claim 4.

6. The product characteristics of the product produced in the melting furnace (3) are measured. The method according to any one of claims 1 to 3.

7. The aforementioned product characteristics are, The CO content in the exhaust gas of the melting furnace, or CO / CO2 in melting furnace exhaust gas 2 It is the volumetric flow rate ratio, or The temperature of the molten metal when a certain amount of energy is input, or The oxygen activity in the molten metal is, or The oxygen activity in the slag, or The total oxygen activity in the molten metal and the slag, or Slag characteristics, such as the chemical composition of the slag or the viscosity of the slag, The proportion of elements in pig iron, or A specific amount of slag The method according to claim 6.

8. The first plant-specific characteristic curve characteristic value of the direct reduction plant (2) obtained empirically. DRA -MG DRA Based on and empirically determined second plant-specific characteristic curve characteristics of the melting furnace (3) 溶融炉 -MG 生成物 Based on the predetermined degree of metallization MG DRA,理論値 It is determined The method according to any one of claims 1 to 7.

9. The aforementioned characteristic value is a measure of the weight of metallized iron per unit time, and is optionally limited to the maximum amount of metallized iron melted per unit time, or The aforementioned characteristic value is a measure of a specific amount of energy conversion, or The aforementioned characteristic value is a specific CO 2 A measure related to emissions, or The aforementioned characteristic value is a measure of a specific total cost. The method according to claim 8.

10. The predetermined degree of metallization MG DRA,理論値 Min[characteristic value] DRA (MG DRA ) + characteristic value 溶融炉 (1-MG) DRA The method according to claim 8 or 9, which is defined as the degree of metallization that satisfies the condition ).

11. The aforementioned degree of metallization MG DRA The modification of the operation to increase the is An increase in the flow rate of reducing gas in the direct reduction plant (2), and / or In the aforementioned direct reduction plant (2), extension of the residence time of iron ore that becomes sponge iron, Increase in the gas temperature of the reducing gas within the range of 560 to 1150°C, preferably 900 to 1150°C. The method according to any one of claims 1 to 10, including the method described in any one of claims 1 to 10.

12. The aforementioned degree of metallization MG DRA The aforementioned modification of the operation to reduce the following: A decrease in the flow rate of reducing gas in the direct reduction plant (2), and / or Shortening of the residence time of iron ore that becomes sponge iron in the direct reduction plant (2) The method according to any one of claims 1 to 11, including the method described in the previous claim.

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