Electric arc furnace operation method and steelmaking equipment

Abstract

The present invention discloses a method of operating an electric arc furnace, the method comprising recovering heated metallurgical gases, including water and carbon monoxide, from at least one unit (12) of a steel plant (100), conducting the metallurgical gases to a reactor (16) via a reactor feed line (14), treating the metallurgical gases in the reactor (16) to convert the carbon monoxide and water to hydrogen and carbon dioxide according to the water-gas shift reaction, and subsequently separating the hydrogen via a separator (18). The method further includes supplying an iron bearing material, including iron primarily in the form of iron oxide, to an electric arc furnace (10); at least partially melting the iron bearing material to obtain a molten bath; conducting hydrogen via a furnace feed line (20) to the electric arc furnace (10) disposed downstream of the furnace feed line (20); and injecting hydrogen into the electric arc furnace (10) via a plurality of hydrogen injectors (26) such that the hydrogen reacts as a reducing agent to reduce the iron oxide in the molten bath during a smelting operation of the electric arc furnace (10).

Description

[Technical field]

[0001] The present invention relates to a method for operating an electric arc furnace, to an electric arc furnace and to a steelmaking installation (steel works, steel mill). [Background technology]

[0002] Modern steelmaking facilities, respectively iron and steel and metal production facilities, are subject to the constraint of reducing their carbon dioxide emissions. For this reason, steelmakers replace the fossil fuels used in their production facilities with so-called "green" electrical energy or "renewable" fuels. In this context, hydrogen is used as a fuel and is therefore considered a key factor in reducing CO2 emissions. However, the production, transportation and storage of large amounts of hydrogen are considerable technical challenges and involve high costs. For this reason, prior art often focuses on the economic aspects of hydrogen production or how to replace fossil fuels with hydrogen in its production.

[0003] The main integrated hydrogen production processes are steam reforming (of natural gas) and electrolysis. Steam reforming of natural gas is currently considered the most common and cheapest industrial hydrogen source. Natural gas (methane) is heated to 700 to 1100 °C in the presence of steam and a nickel catalyst. The methane molecules are decomposed to form carbon monoxide and hydrogen. The carbon monoxide gas is passed over iron oxide or other oxides together with the steam, and additional hydrogen can be obtained by the so-called water-gas shift reaction. The hydrogen produced in this way is economically attractive, but still requires fossil fuels. To completely avoid CO2 emissions during hydrogen production, the CO2 must be captured and stored. In electrolysis, hydrogen is produced by a unit composed of several electric cells, each cell having an anode and a cathode immersed in an electrolyte and connected to a power source.

[0004] However, both methods, steam reforming and electrolysis, are very expensive and require significant amounts of energy as well as a large, safe infrastructure for the transportation and storage of hydrogen. If one of these methods is set up to operate in an industrial environment, the corresponding production facilities are usually completely isolated from high-temperature areas, mainly for safety reasons. This has the significant drawback that valuable resources, such as space and energy, may simply be used inefficiently in and on such facilities.

[0005] In the prior art, there exist electric furnaces such as electric arc furnaces (EAFs), which are used to produce steel from a charge mixture typically made by scrap and hot metal, the EAF mainly performs the melting process, and can also perform the reduction of iron oxides, if these are present in the charge mixture.

[0006] However, such reduction can only be carried out in limited quantities due to process constraints. Such EAFs typically require an intercalation mixture with a high degree of metallization. For this reason, when iron oxides are included in the EAF input feed, they generally originate from direct reduced iron (DRI) with a degree of metallization higher than 88%, produced by previous gas-based direct reduction processes. Such EAFs are called "directly heated" because they generate a high concentration of heat released from the electric arc formed between the electrodes and the melt.

[0007] Another type of electric furnace, the so-called submerged arc furnace (SAF), has been developed to reduce and melt metal oxides. These SAFs are able to carry out the complete reduction process starting from ores of metals such as nickel, chromium, copper or iron. In SAF, an electrode is immersed in the molten material, respectively the slag or the top of the molten bath, utilizing a heating principle based on the Joule effect due to an electric current generated by an electrode in a slag with high electrical resistance. In general, the process parameters in SAF are different from the previously mentioned EAF. SAF allows the complete reduction process from iron or other metal ores.

[0008] The reduction process in the EAF and SAF is carried out by carbon, generally in the form of coke or anthracite, as the reducing agent, which can be injected through a suitable lance or charged from a top-charging system.

[0009] When pre-reduced iron pellets, direct reduced iron (DRI) or hot-briquette reduced iron (HBI) are included in the feedstock being melted, part of the carbon required for the reduction process is already contained in the DRI or HBI pellets. Thus, the reduction reaction in the EAF is carried out by both the injected carbon and the carbon present in the directly reduced iron.

[0010] Carbon not only acts as a reducing agent in the EAF and SAF, but is also required to maintain proper process conditions in terms of reaction kinetics, overall energy balance, heat transfer coefficients and process yields.

[0011] Such furnaces therefore have the disadvantage that they emit relatively large amounts of carbon dioxide during their operation. Object of the invention

[0012] It is therefore an object of the present invention to provide a method for operating an electric arc furnace in a steelmaking facility, in which the amount of carbon dioxide emitted is significantly reduced.

[0013] This object is achieved by the subject matter of the independent claims. Summary of the Invention

[0014] The present invention proposes a method for operating an electric arc furnace, the method comprising recovering heated metallurgical gases comprising water and carbon monoxide from at least one facility of a steelmaking facility. The metallurgical gases are led to the reactor by a reactor feed line. The method comprises further converting the carbon monoxide and water contained in the metallurgical gases into hydrogen and carbon dioxide according to the water-gas shift reaction by processing the metallurgical gases in the reactor, and subsequently separating the hydrogen by a separation device. The method is characterized in that it further comprises providing an iron-containing material comprising iron mainly in the form of iron oxide to the electric arc furnace, at least partially melting the iron-containing material to obtain a molten bath, conducting hydrogen by a furnace feed line to the electric arc furnace arranged downstream of the furnace feed line, and injecting hydrogen into the molten bath in the electric arc furnace by a plurality of hydrogen injection devices, such that the hydrogen reacts as a reducing agent for reducing the iron oxide in the molten bath during the refining operation of the electric arc furnace.

[0015] The method is based on the finding that hydrogen can be produced and used in a more sustainable and environmentally friendly way in steelmaking facilities, and that it can be advantageously used as a reducing agent in electric arc furnaces operated as electric smelters. It has been found that hydrogen (H2) can be separated from several metallurgical gases emitted from different on-site facilities of a steelmaking facility, each of which is a separate facility. For example, hydrogen can be obtained / produced by steam injected into a CO2-rich gas, such as blast furnace gas, by utilizing the water-gas shift reaction.

[0016] "Metallurgical gas" can generally refer to any gas emitted from a metallurgical installation, such as a (blast) furnace, stove, coke battery or similar installation. Metallurgical gas forms the basis of the so-called synthesis gas, respectively synthesis gas, a fuel gas mixture containing mainly hydrogen, carbon monoxide and very often some carbon dioxide.

[0017] In particular, the method aims to exploit the availability of synthesis gas containing hydrogen and / or carbon monoxide in steelmaking facilities, the carbon monoxide being used for the separation of hydrogen by steam. Synthesis gas can be obtained from metallurgical gas, for example by carrying out the Boudouard reaction and / or the water gas shift reaction, according to known techniques. Alternatively, hydrogen may also be produced by other processes, for example natural gas reforming, biomass reforming, steam reforming, etc. An example of a metallurgical gas may be blast furnace gas. Blast furnace gas comprises or consists of about 20-30 vol.% CO2, about 35-50 vol.% N2 and about 20-30 vol.% CO, and about 5% H2. Another example of a metallurgical gas is the so-called "converter gas". Converter gas comprises or consists of about 60-70% CO, about 10-20% CO2, about 0-5% H2, and about 5-15% N2. Another example of a metallurgical gas is "coke oven gas". Coke oven gas contains or consists of about 5-10% CO, about 50-55% H2, about 20% CH4 and / or other hydrocarbons, about 10% or less N2, and small amounts of CO2. Note that this composition as well as exemplary percentages can vary significantly depending on process conditions. Metallurgical gases can be mixed with steam for heating and / or water addition.

[0018] Metallurgical gases can be treated by commonly known methods to separate hydrogen from other compounds. For example, water-gas shift (WGS) reactions and / or carbon dioxide removal methods can be used to convert carbon monoxide (CO), which forms part of the metallurgical gas, to carbon dioxide. Carbon dioxide is then easily separated from the metallurgical gas (more easily than carbon monoxide), so that the remaining metallurgical gas contains a large amount of hydrogen, respectively a specific high concentration of hydrogen.

[0019] It has further been found that recovery of hydrogen gas by separating it from gases emitted by already existing processes and installations makes it possible to provide, maintain and operate electric arc furnaces in a particularly economical and environmentally friendly manner.

[0020] The method is further based on the finding that hydrogen can be introduced into an electric arc furnace (EAF), where it is injected into the molten bath, respectively the slag, thereby operating the electric arc furnace as an electric smelter. During such operation of the EAF, hydrogen is used as a reducing agent instead of carbon in producing steel from iron-containing material mainly in the form of iron oxide. As a result, the amount of carbon dioxide emitted from such EAF as well as from metallurgical facilities can be significantly reduced. "Mainly" in this context means that more than 50% by weight of the iron-containing material is in the form of iron oxide, preferably at least 60%, for example at least 70%, at least 80%, or even more than 85%.

[0021] "Electric arc furnace" generally refers to an industrial furnace configured for smelting processes by electric arc. The electric arc in the electric arc furnace is generated between electrodes or between electrodes and molten material, metal bath or slag, respectively) Electric arc furnaces may be operated and configured to maintain the process conditions required for reduction processes using hydrogen. The process conditions may be characterized by parameters such as pressure, temperature, reaction kinetics, heat transfer coefficients or similar parameters. Electric arc furnaces may be powered by direct current or alternating current.

[0022] A "facility" generally refers to any collection of industrial equipment or devices constructed, installed, or established to serve a particular purpose. For example, a facility may include or consist of a blast furnace, a coke oven battery, or a hot blast stove.

[0023] "Steel making facility", respectively "steel plant", generally refers to an industrial facility where iron and steel and / or metals are produced.

[0024] "Reactor" generally refers to a device used as a vessel / tank / receptacle for chemical reactions. A reactor may also include multiple vats separated from each other, for example by (semi-)permeable filters or catalysts. For example, a reactor may be configured to convert carbon monoxide and water contained in metallurgical gases into hydrogen and carbon dioxide.

[0025] "Furnace feed line" generally refers to a gas pipeline that introduces gas, especially hydrogen, into a furnace, such as an electric arc furnace.

[0026] "Reducing agent" generally refers to a substance that reduces a compound by donating electrons. According to the electric arc furnaces of the prior art, iron oxide in the slag could be reduced by the injection of coal. Furthermore, for example, carbon monoxide, which is also present in the melt, slag or bath in the EAF, can also act as a reducing agent for the iron oxide. The reduction reaction in the EAF can be based on hydrogen as well as electrical energy. As a result, hydrogen can completely or at least partially replace carbon as a reducing agent, preferably to at least 25 mol.%, advantageously at least 50%, preferably at least 60%, for example at least 70%, at least 80% or even almost 100 mol.%. In other words, carbon, which is currently used in state-of-the-art electric arc furnaces as a reducing agent, may be partially or completely replaced by hydrogen. Carbon dioxide emissions can be completely prevented or at least significantly reduced.

[0027] "Conduction" generally refers to the act of directing, conveying or transmitting a gas, for example by providing a conductor or pathway in the form of a pipe, tube, line, (gas) pipeline or similar technical element. "Reactor supply line" generally refers to a gas pipeline that supplies gas to a reactor.

[0028] "Recovery" generally refers to the process of separating, isolating, storing, absorbing, capturing, trapping, and / or preventing the emission or release of gases into the external environment, e.g., gas. For example, metallurgical gases emitted from a blast furnace may be captured by suitable filters and / or separation equipment.

[0029] "Injection" generally refers to the introduction of a gas into a facility, such as an EAF, or into a melt or mixture of compounds within the facility, such as a slag. Injection can be performed using an injector. "Injector" generally refers to any device used or configured to inject a gas, such as hydrogen or oxygen, into a facility or into a melt or mixture of compounds within the facility. For example, the injector may be submerged in the molten bath.

[0030] "Action" generally refers to the act of functioning.

[0031] "Smelting" generally refers to the process of melting and reducing metal bearing materials, e.g., metal ores, such as iron bearing materials that contain iron primarily in the form of iron oxide, which results in a chemical change or reaction within the molten state, resulting in the separation of a metal, e.g., metallic iron.

[0032] "Separation" generally refers to the act of separating gas components from a gas mixture. For example, after metallurgical gases are converted in a reactor to hydrogen, carbon dioxide and possibly further by-products, the hydrogen can be separated by the mixture, for example, using a filter or membranes. Furthermore, separation can also be performed by known methods, such as, for example, gas separation methods based on cryogenic distillation, swing adsorption techniques, Hampson-Linde cycles or similar separation methods. "Separation device" generally refers to an apparatus or set of connected devices used or configured to operate a separation step or method.

[0033] "Transformation" generally refers to a change in composition, structure, form or appearance of one or more substances, such as, for example, a gas mixture.

[0034] "Processing" or "processing" generally refers to subjecting something to the action of an agent, catalyst, energy, chemical, biological or physical influence or process. For example, processing may include directing metallurgical gases through a heated catalyst in a reactor.

[0035] In some embodiments, the metallurgical gases have a temperature in the temperature range of 20 ° C to 100 ° C after the associated gas cleaning. It has been found that the metallurgical gases can be preheated in a suitable heat recovery system, making use of some available heat from other processes in the integrated steelmaking facility and can be converted in subsequent reactions in a particularly energy-efficient manner. The metallurgical gases may be commonly available at temperatures between 20 ° C to 100 ° C, preferably at temperatures below 50 ° C. The metallurgical gases may be stored in a gas holder after gas cleaning, for example in a scrubber. It is noted that, depending on their configuration, these heated metallurgical gases may be subjected to known heat recovery methods.

[0036] The process for converting carbon monoxide and water to hydrogen and carbon dioxide includes at least the water gas shift reaction, which is carried out in the presence of a catalyst. The "water gas shift reaction", the water gas shift reaction or the water gas shift reaction, respectively, is a process for reducing / reducing the carbon monoxide content in synthesis gas and producing hydrogen. The reaction equation is also known as the conversion equilibrium: CO + H2O ⇔ CO2 + H2.

[0037] In some embodiments, the method further comprises, following separating the hydrogen, conducting the hydrogen via a storage supply conduit to a hydrogen storage tank. A "storage supply conduit" generally refers to a pipeline used or configured to conduct hydrogen to a hydrogen (storage) tank.

[0038] In some embodiments, the method further includes discharging hydrogen from the hydrogen storage tank via a furnace feed line to the electric arc furnace.

[0039] In some embodiments, the method further includes heating the hydrogen upstream of the electric arc furnace such that the hydrogen has a temperature in the range of 25 to 700° C. when the hydrogen is injected into the electric arc furnace. Heating the hydrogen increases the pressure, which in turn promotes distribution of the injected hydrogen in the molten bath. Note that "heating" can also refer to the process of pre-heating the hydrogen gas before it is injected into the EAF.

[0040] In some embodiments, the plurality of hydrogen injectors comprises at least one supersonic gas lance for injecting at least a portion of the hydrogen supplied to the electric arc furnace into the furnace, in other words, the gas is injected at supersonic speed.

[0041] In some embodiments, the hydrogen injected through the supersonic gas lance is greater than 10 m 3 / min~500m 3 / min range throughput.

[0042] In some embodiments, the method further includes injecting oxygen into the electric arc furnace via a plurality of oxygen injectors. The oxygen may be injected to oxidize iron at least partially within the bath and within the slag, respectively. In other words, the oxygen oxidizes at least a small amount of iron to wustite (FeO) within the bath, utilizing heat released from exothermic reactions that may be needed locally to maintain the required process conditions.

[0043] In some embodiments, the method further includes introducing lime into the electric arc furnace by a lime introduction device. "Lime introduction device" generally refers to any device used or configured for the introduction, respectively injection, of lime into an electric arc furnace or into the slag layer in an electric arc furnace. The lime may, for example, include or consist of quicklime. The lime may be used as a flux for cleaning steel in an electric arc furnace (EAF). For example, lime may be used to remove sulfur, silica, phosphorus, and similar materials.

[0044] In some embodiments, the method further includes inserting / introducing material into the electric arc furnace, the material including at least one of iron oxide, pre-reduced iron ore pellets, direct reduced iron (DRI), hot briquetted iron briquettes (HBI), blast furnace grade, DR grade iron ore pellets or fines, or mixtures thereof. For example, the small amount of carbon that may be used to heat the smelt may be provided by direct reduced iron in the form of cold pellets or hot briquettes. These reduced irons may be produced by natural gas-based direct reduction processes.

[0045] In some embodiments, the method further comprises supplying electrical energy to the electric arc furnace, the electrical energy being used to operate the EAF, the electrical energy being obtained from a renewable energy source. "Renewable energy source" generally refers to a source that provides electrical energy based on at least one of solar energy, wind energy, hydroelectric energy, biomass energy, geothermal energy, tidal energy and wave energy, or mixtures thereof. Through the use of a renewable energy source, the method enables largely or completely CO2-free "green steel" production, provided that only iron ore and / or DRI / HBI from a hydrogen-based direct reduction process are charged to the EAF as ferrous bearing material.

[0046] The present invention further comprises an electric arc furnace, Recovering heated metallurgical gases comprising water and carbon monoxide from at least one of the steelmaking facilities; conducting metallurgical gases to the reactor via a reactor supply line; The treatment of the metallurgical gas in the reactor converts carbon monoxide and water into hydrogen and carbon dioxide according to the water-gas shift reaction, followed by Hydrogen is separated by a separator. It was done like this, feeding an iron-containing material, the iron being primarily in the form of iron oxide, into an electric arc furnace; at least partially melting the iron-containing material to obtain a molten bath; conducting hydrogen through a furnace feed line to an electric arc furnace disposed downstream of the furnace feed line; The present invention relates to a steelmaking facility configured to inject hydrogen into a molten bath of an electric arc furnace by a plurality of hydrogen injectors such that the hydrogen acts as a reducing agent for reducing iron oxide in the molten bath during a refining operation of the electric arc furnace. The aforementioned improvements and embodiments of the method according to the invention also apply to steel making plants.

[0047] Further aspects and features of the invention emerge from the dependent claims, the accompanying drawings and the following description of embodiments. [Brief description of the drawings]

[0048] Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: [Figure 1] 1 is a schematic diagram showing the method according to the invention, an electric arc furnace and a steelmaking installation; [Diagram 2] FIG. 1 is a schematic diagram showing an electric arc furnace according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] FIG. 1 shows a schematic diagram of the method according to the invention as well as an electric arc furnace 10 and a steelmaking installation 100. The steelmaking installation 100 comprises an installation 12 consisting of a blast furnace 12 which discharges heated metallurgical gases containing water and carbon monoxide. The gases from the blast furnace have a temperature in the range of about 200° C. to 300° C. The metallurgical gases can be cleaned by a scrubber and stored in a gas holder (not shown). As shown in FIG. 1, the metallurgical gases released by the blast furnace 12 are captured and led by / through a reactor feed line 14 to a reactor 16. The metallurgical gases have to be preheated for the hydrogen production process, for example by mixing the metallurgical gases with steam (not shown), the steam providing the heat and water required for the water-gas shift reaction.

[0050] Further devices (not shown), such as temperature sensors, pressure sensors, flow meters and (automatic) valves, may be arranged on and / or in the reactor supply line 14. These further devices may be connected to a control device, such as, for example, a computer (not shown). The control device may be configured to determine process parameters related to the metallurgical gases, such as, for example, the temperature of the metallurgical gases, the pressure of the metallurgical gases and / or the velocity of the metallurgical gases. Depending on these process parameters, the control device may determine by software whether the valves arranged in the reactor supply line 14 should be fully opened, partially opened or closed.

[0051] Metallurgical gases conducted through reactor feed line 14 are introduced into reactor 16, where carbon monoxide and water compounds in the metallurgical gases are converted into carbon dioxide and hydrogen. The conversion of carbon monoxide and water into hydrogen and carbon dioxide is based on the water-gas shift reaction in the presence of a catalyst, e.g. a nickel-based catalyst (not shown). Before the metallurgical gases are processed in the reactor, further steps can be carried out upstream of the reactor to heat the gases and / or to separate substances, e.g. gaseous sulfur compounds, from the metallurgical gases that would harm the catalyst (not shown).

[0052] After the gases are treated in the reactor, they are conducted to a separator 18, where the hydrogen is separated from other compounds of the metallurgical gases. In a next step, the hydrogen is conducted by the furnace supply line 20 either directly to the electric arc furnace arranged downstream of the furnace supply line 20 or via a supply conductor 22 to a hydrogen storage tank 24. To operate the passage of the hydrogen towards the tank 24 and / or the electric arc furnace 10, (automatic) valves are arranged in the supply conductor 22 and in the furnace supply line 20 (not shown). The valves are equipped with actuators operated by a computer. Furthermore, both the furnace supply line 20 and the supply conduit 22 are equipped with pressure sensors, flow meters and temperature sensors (not shown), respectively, connected to a computer. The hydrogen is conducted directly into the furnace or into a storage tank 24, depending on the requirements of the electric arc furnace 10. If the hydrogen is stored in the tank 24, the hydrogen may be released into the electric arc furnace at a predetermined rate and / or amount. As can be further derived from FIG. 1, a discharge line 23 for discharging the hydrogen is in fluid communication with the furnace supply line 20. The discharge line 23 is equipped with a temperature sensor, a flow meter, a pressure sensor and an (automatic) valve, each of these elements being connected to and operated by a control device (not shown).

[0053] Furthermore, the furnace feed line 20 may be equipped with an optional heating device (not shown), also controlled by a computer, which makes it possible to heat the hydrogen upstream of the electric arc furnace, so that the hydrogen has a temperature in the range of 25°C to 700°C when injected into the electric arc furnace.

[0054] Hydrogen is injected into the electric arc furnace 10 via / by a number of injectors 26, as shown in more detail in FIG. 2. Two horizontal dashed lines in the furnace represent the boundary between the slag region 34 and the liquid metal region 36. During operation of the electric arc furnace, a slag layer 34 forms on the surface adjacent to the electrodes (not shown). Beneath the slag layer 34, a liquid metal layer 36 is generated after the electric arc furnace 10 has been operating for a certain period of time. The electrode(s) of the EAF protrude from the top, respectively from the furnace hat (not shown), into the slag. In other words, the electrodes are at least partially immersed in the slag.

[0055] The multiple hydrogen injectors 26 also include supersonic gas lances 28 which protrude from the top of the reactor, each from the reactor cover, into the liquid metal region 36. During operation of the EAF, hydrogen is injected into the reactor at a flow rate of preferably 10 m 3 / min~500m 3 The gas is injected through a supersonic gas lance 28 at a rate in the range of 1 / min.

[0056] The electric arc furnace 10 is also provided with a number of oxygen injectors 30, lances, respectively, for injecting oxygen into the electric arc furnace 10. The oxygen injectors 30 are spaced apart from the hydrogen injectors 26 and the supersonic gas lance 28. It should be noted that the oxygen injectors 26 may also comprise or consist of a supersonic gas lance.

[0057] 2, the lime introducers 32 protrude into the liquid metal region 32 of the electric arc furnace and at the interface between the liquid metal region 32 and the slag region 34, respectively. The lime introducers 32 provide an injection of lime during operation of the electric arc furnace.

[0058] During operation of an electric arc furnace, material is inserted into the hearth of the furnace. The material may include at least one of the following: scrap iron, iron oxide, pre-reduced iron ore pellets, direct reduced iron (DRI), hot briquetted iron (HBI), blast furnace grade, DR grade iron ore pellets or fines or mixtures thereof. The electric arc furnace is powered by electrical energy, which may be obtained from a renewable energy source.

[0059] The injected hydrogen is used to reduce iron oxide (e.g., FeO) to iron (Fe) and water according to the following reaction equation: FeO+H2→Fe+H2O.

[0060] Moreover, the injected hydrogen is further used to react with oxygen releasing heat according to the following equation: H2+1 / 2O2→H2O.

[0061] The injected oxygen is used to oxidize iron (Fe) according to the following equation: Fe+1 / 2O2→FeO.

[0062] As can be seen from FIG. 2, the amount of carbon dioxide decreases entirely, or at least significantly, during operation of the electric arc furnace 10 .

[0063] The described embodiments are examples of the invention. The described components of each respective embodiment represent individual features of the invention which should be considered independently of one another. These features should therefore also be considered as components of the invention individually or in combinations other than those shown. Moreover, the described embodiments may be supplemented by further features of the invention already described.

[0064] Further features and embodiments of the invention will occur to those of ordinary skill in the art in the context of this disclosure and the claims. [Explanation of symbols]

[0065] 10 Electric Arc Furnace 12 Equipment 14 Reactor supply line 16 Reactor 18 Separation device 20 Furnace Supply Line 22 Storage and supply conductor 23 Discharge Line 24 Tank 26 Hydrogen Injection Equipment 28 Lance 30 Oxygen Injection Device 32 Lime introduction device 34 Slag Area 36 metal layer 100 Steelmaking equipment

Claims

1. A method of operating an electric arc furnace (10), comprising the steps of: Recovering heated metallurgical gases comprising water and carbon monoxide from at least one facility (12) of a steelmaking facility (100); conducting said metallurgical gases to a reactor (16) via a reactor supply line (14); treating said metallurgical gas in said reactor (16) to convert carbon monoxide and water into hydrogen and carbon dioxide according to the water gas shift reaction; subsequently separating the hydrogen by a separation device (18), The method comprises: feeding an iron-containing material containing iron mainly in the form of iron oxide to said electric arc furnace (10); at least partially melting the iron-containing material to obtain a molten bath; conducting said hydrogen through a furnace feed line (20) to said electric arc furnace (10) located downstream of said furnace feed line (20); and injecting the hydrogen into the molten bath of the electric arc furnace (10) via a plurality of hydrogen injectors (26) such that the hydrogen acts as a reducing agent for reducing iron oxide in the molten bath during a smelting operation of the electric arc furnace (10).

2. The method of claim 1 , wherein the heated metallurgical gas has a temperature in the range of 20° C. to 100° C.

3. 3. The method of claim 1 or 2, wherein the water gas shift reaction is carried out in the presence of a catalyst.

4. 3. The method of claim 1, further comprising conducting the hydrogen through a storage supply conductor (22) to a hydrogen storage tank (24) and discharging the hydrogen from the hydrogen storage tank (24) through the furnace supply line (20) to the electric arc furnace (10).

5. 3. The method of claim 1 or 2, further comprising the step of heating the hydrogen upstream of the electric arc furnace such that the hydrogen has a temperature in the range of 25° C. to 700° C. when injected into the electric arc furnace.

6. 3. The method of claim 1 or 2, wherein the plurality of hydrogen injectors (26) comprises at least one supersonic gas lance (28) for injecting at least a portion of the hydrogen supplied to the electric arc furnace (10) into the furnace.

7. The hydrogen injected through the supersonic gas lance (28) is ３ / min~500m ３ 7. The method of claim 6, having a throughput in the range of 1000 / min.

8. The method of claim 1 or 2, further comprising injecting oxygen into the electric arc furnace (20) via a plurality of oxygen injectors (30).

9. 3. The method of claim 1 or 2, further comprising the step of introducing lime into the electric arc furnace (10) by a lime introduction device (32).

10. 3. The method of claim 1 or 2, wherein the method further comprises inserting a material into the electric arc furnace, the material comprising at least one of iron oxide, pre-reduced iron ore pellets, direct reduced iron (DRI), hot briquetted iron briquettes (HBI), blast furnace grade, DR grade iron ore pellets or fines or mixtures thereof.

11. 3. The method of claim 1 or 2, further comprising the step of operating the electric arc furnace with electrical energy obtained from a renewable energy source.

12. A steelmaking installation (100) comprising an electric arc furnace (10), Recovering heated metallurgical gases comprising water and carbon monoxide from at least one of the steelmaking facilities (100); conducting said metallurgical gases to a reactor (16) via a reactor supply line (14); Processing of the metallurgical gas in the reactor (16) converts carbon monoxide and water into hydrogen and carbon dioxide according to the water gas shift reaction, followed by The hydrogen is separated by a separator (18). It is configured as follows: Providing an iron-containing material, comprising iron primarily in the form of iron oxide, to an electric arc furnace (10); at least partially melting the iron-containing material to obtain a molten bath; conducting said hydrogen through a furnace feed line (20) to said electric arc furnace (10) located downstream of said furnace feed line (20); a plurality of hydrogen injection devices (26) configured to inject hydrogen into a molten bath of the electric arc furnace (10) so that the hydrogen acts as a reducing agent for reducing iron oxide in the molten bath during a refining operation of the electric arc furnace (10).

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