Iron ore reduction and melting equipment and method

Abstract

An iron ore reduction and melting plant comprising:-a furnace comprising, from the bottom to the top, a hearth, a tuyere layer, a stack layer and a top layer, said blast furnace comprising at least one first gas injector on the tuyere layer; -at least one first reducing gas generator connected to the at least one first gas injector wherein the apparatus is adapted to provide a reducing gas comprising 30%-100% (vol / vol) hydrogen over the tuyere layer and to operate at a coke ratio below 200 kg / t of molten iron.

Description

Background Art

[0001] The production of molten iron (hm) containing reduced iron generally requires a (oxidized) iron source (i.e., iron ore), a reducing agent (coke, reducing gas) that allows the oxidized form of iron to be reduced to reduced iron, and reagents (coke, coal, oxygen, heater) that provide the required reaction temperature and energy for the reaction. Since coke is used in the reduction process, the reduction process produces a large amount of CO2.

[0002] It is generally desirable to reduce the CO2 output during reduction processes.

[0003] It is therefore an object of the present invention to provide an apparatus and a method capable of producing molten iron with reduced CO2 output. Summary of the invention

[0004] The invention is defined by the appended claims.

[0005] Disclosed is an iron ore reduction and smelting device, the iron ore reduction and smelting device comprising:

[0006] a furnace, for example a blast furnace, comprising from the furnace bottom to the furnace top: a furnace chamber, a tuyere layer, a furnace shaft layer and a furnace top layer, the furnace comprising at least one first gas injector on the tuyere layer, and

[0007] - a reducing gas generator connected to the at least one gas injector, wherein the apparatus is adapted to operate at a coke rate below 200 kg / t hot metal.

[0008] By providing the reducing agent outside the furnace, the amount of coke (and optionally coal) required for the reduction process, which would otherwise be used to provide the reducing agent for the iron ore, can be reduced. The reducing agent, such as a reducing gas, may include hydrogen (H2) and carbon monoxide (CO). In this way, a coke ratio of less than 200 kg / t of hot metal can be achieved. Hydrogen is typically provided as molecular hydrogen (H2).

[0009] The reducing agent may comprise 30%-100% (vol / vol) hydrogen, optionally also comprising 10%-70% (vol / vol) CO and less than 35%, 10% or 5% (vol / vol) of gaseous compounds other than CO or H2.

[0010] The first reductant generator may be a gas reformer providing H 2 , in particular a synthesis gas reformer providing H 2 and CO.

[0011] The blast furnace may also include at least one lock hopper for introducing material from atmospheric pressure into the furnace at furnace pressure.

[0012] The at least one lock hopper ensures that the pressure within the blast furnace is maintained and thus the reduction and melting processes can be maintained.

[0013] The iron ore reduction and smelting apparatus may further comprise at least one second gas injector located on the shaft layer.

[0014] The at least one second gas injector may be located (eg directly) above the root of the cohesion zone, an area of ​​the cohesion zone directly contacting the wall of the furnace (ie above the root of the cohesion zone).

[0015] It has surprisingly been found that the total coke requirement can be further reduced by supplying the reducing agent also at the shaft level. In this way, the required temperature level for melting the ore can be achieved while providing less energy to the reducing agent at the tuyere level. Furthermore, the amount of reducing agent injected at the tuyere level can be reduced. Furthermore, with shaft injection, less gas needs to pass through high resistance agglomeration areas.

[0016] The at least one first gas injector may include at least one electrically driven heater.

[0017] The advantage of an electrically driven heater is that it can be used to heat the reducing agent without local consumption of coal or coke. Since the heater is electrically driven, the energy required for the heater can be generated by a CO2-lean energy source. A CO2-lean energy source is an energy source that produces a small amount of CO2 (photovoltaic, wind, hydro or nuclear energy) or an energy source that produces no more CO2 than the amount used in its production (e.g. biogas from non-carbonized plant materials).

[0018] The path of the reducing agent generated in the reducing gas generator may include the reducing gas generator, the pipe between the gas generator and the ring pipe, the ring pipe, the pipe between the ring pipe and the gas injection points at the furnace (downcomers, elbows and blowpipes) and the tuyere. Gas injectors as used in this document include blowpipes and tuyeres.

[0019] The apparatus may be adapted to provide heated reducing agent in the conduit between the gas generator and the annulus, in the conduit between the annulus and the gas injector and / or in the gas injector. Preferably, the apparatus may be adapted to provide heated reducing agent in the conduit between the annulus and the gas injector.

[0020] The apparatus, preferably, at least one first gas injector may be adapted to heat the reducing agent to 1600°C-2600°C, 1900°C-2300°C, or 2100°C-2200°C, and provide the heated gas to the furnace at the tuyere layer.

[0021] At these temperatures, the reduction of the ore by the reducing agent is effective and the amount of coke and coal gasified at the tuyere can be reduced.

[0022] The device can be used to 500Nm at the tuyere layer. 3 / t-1300Nm3 / t、900Nm 3 / t-1300Nm 3 / t or 770Nm 3 / t-1000Nm 3 / t volume flow rate of molten iron is used to inject reducing gas into the blast furnace.

[0023] The equipment can be used to 200Nm at the furnace layer 3 / t-800Nm 3 / t, 250Nm 3 / t-700Nm 3 / t or 250Nm 3 / t-600Nm 3 / t volume flow rate of molten iron is used to inject reducing gas into the blast furnace.

[0024] At these volume flow values, the reduction of the ore by the reducing agent is effective, and the amount of coke and coal can be further reduced.

[0025] The at least one first gas injector may be designed to heat the reducing agent to inject the reducing agent at a pressure of at least 2 bar up to 10 bar absolute, 5 bar to 6 bar absolute, or 4 bar to 5 bar absolute.

[0026] At these pressure values, the reduction of the ore by the reducing agent is efficient and high production rates can be achieved.

[0027] Preferably, each of the above three conditions concerning temperature, volume flow and pressure relative to at least the first gas injector are combinable.

[0028] The at least one electrically driven heater of the at least one first gas injector is adapted to operate at an electrical power of 200 kwh / t - 700 kwh / t, 250 kwh / t - 600 kwh / t or 300 kwh / t - 550 kwh / t of molten iron.

[0029] The electrical power is suitable for heating the reducing agent to a desired temperature.

[0030] The electrically driven heater may be a plasma torch. A plasma torch is an electrically driven device capable of heating a gas to the physical state of a plasma. A plasma torch can provide high temperature gases that cannot be achieved by conventional heating systems. In addition, a plasma torch allows for flexible operation in terms of flow rate and temperature. In addition, it is a compact technology with a small volume footprint.

[0031] Plasma torches are particularly (energy) efficient in providing the desired temperature and are particularly efficient in heating the gas from an already high temperature to an even higher temperature, which is almost impossible with standard technology. Therefore, by configuring the apparatus to provide the plasma torch with a gas heated to at least 900°C or preferably 1100°C, a plasma torch with a reduced power requirement can be used.

[0032] The plasma torch may be an electrode-containing or electrodeless plasma torch.

[0033] In an electrodeless plasma torch, the plasma is ignited by induction, so no electrodes are required.

[0034] The electrodeless plasma torch may be a microwave (MW) plasma torch and a radio frequency (RF) plasma torch.

[0035] The plasma torch may also be a plasma torch comprising an electrode. The electrode may be a graphite electrode.

[0036] The plasma torch comprising the electrode may be a direct current plasma torch (DC plasma torch) or an alternating current plasma torch (AC plasma torch), in particular a 3-phase AC plasma torch.

[0037] Plasma torches containing electrodes are very energy efficient in providing the required temperature for the gas to be injected into the furnace.

[0038] The advantage of a DC plasma torch is that it is quite compact in size, i.e. it does not require a lot of space.

[0039] AC plasma torches, especially 3-phase AC plasma torches, are less compact in size but offer many advantages.

[0040] AC plasma torches, specifically 3-phase AC plasma torches, provide diffuse plasma. The plasma is confined to the ignition area, allowing for better control of the location of the plasma. Due to the AC, the electrodes cool naturally, extending their life. The AC plasma torch can be water-cooled. Using a properly designed housing helps to optimize heat transfer and efficiency losses. The AC plasma torch does not require vortex gas like a DC plasma torch, and the design of the torch is simplified. Because the extension of the plasma can be limited, refractory materials are only required in a small area.

[0041] The inter-electrode distance of a plasma torch, in particular a 3-phase AC plasma torch, can be adjusted by moving the tilted electrodes. The inter-electrode distance can be 0 mm-100 mm, 5 mm-50 mm or 40 mm. This adjustability allows for easy plasma ignition and greater plasma controllability, and therefore stability.

[0042] AC plasma torches, specifically 3-phase AC plasma torches, may have 3 or multiples of 3 electrodes (e.g., 3, 6, 9, 12, 15, 18, 21 electrodes or more). A greater number of electrodes may improve control of the plasma and increase the plasma torch power.

[0043] A DC plasma torch may have 2 electrodes or multiples of 2 (e.g., 2, 4, 6, 8, 12, 14, 16, 18, 20). A greater number of electrodes may improve control of the plasma and increase the plasma torch power.

[0044] The total power requirement of the furnace as defined above is between 25 MW and 280 MW, which of course depends largely on the production level of the furnace.

[0045] Plasma torches with a power of 1 MW-10 MW, preferably 2 MW-8 MW, most preferably 3 MW-5 mw, in particular DC plasma torches and / or AC plasma torches and / or 3-phase AC plasma torches, can be used in the furnace as defined above.

[0046] In a furnace as defined above, at least 10 gas injectors and up to 70 gas injectors are used, most preferably 18 to 40.

[0047] In this way, the gas injected into the furnace is heated evenly, providing an efficient metal product.

[0048] The apparatus may also include a power source for powering at least one or more plasma torches.

[0049] Preferably, one power supply powers 1 to 5, 1 to 3 or 1 plasma torch of the at least one plasma torch.

[0050] Using multiple plasma torches powered by multiple power supplies up to 30MW or <10MW (one power supply driving at least one plasma torch) has advantages over using a single power supply with a total capacity equal to the sum of the capacities of all the lower capacity power supplies. In the former case, the flicker caused by fluctuations in the operation of the plasma torches is far less severe on the grid than in the latter case. It may be advantageous to use a power supply up to 3 times the power of a single plasma torch in conjunction with each corresponding plasma torch to provide stable operation.

[0051] Furthermore, using multiple power sources up to 30MW or <10MW gives better controllability and flexibility: when the power source fluctuates or collapses, there is no disturbance propagating to the whole system and the furnace can keep running without serious problems because other power sources can jointly provide the power input of the collapsed power source.

[0052] In addition, one or more backup power supplies can be installed online, and in the event of a failure in the primary power supply, switching to the backup power source ensures stable operation at full power. Repairs can be performed during the next scheduled maintenance shift, so there is no loss of production.

[0053] However, a large number of power supplies results in high costs, high power losses and high space requirements, therefore an optimal number of power units must be selected.In a furnace as defined above, at least 10 power units and up to 70 power units are used, most preferably 18 to 40 power units.

[0054] The plasma torch may be a 3-phase AC plasma torch adapted to provide a (gas) velocity of 10 m / s-120 m / s, preferably 15 m / s-80 m / s, more preferably 18 m / s-60 m / s within the arc perimeter of the plasma torch. Within these ranges, optimal conditions for heating the gas are provided. If not all of the gas to be heated can pass through the perimeter, the remainder of the gas to be heated will be supplied outside the perimeter.

[0055] Furthermore, the present invention provides a plasma torch and a method of using the plasma torch, which reduces the heat load on the wall lining around the plasma torch.

[0056] Thus, the plasma torch may be adapted to split the incoming gas into two gas streams. Specifically, the configuration of the plasma torch provides a first gas stream flowing centrally through an arc generated by the plasma torch and a second gas stream flowing around the periphery of the arc.

[0057] The central gas stream can flow through the plasma arc and will be heated to very high temperatures. A second gas stream can be injected soon downstream of the plasma arc, oriented so that it protects the refractory lined walls of the plasma burner chamber from the heat of the central high temperature gas stream. This reduces the heat load on the wall lining.

[0058] The iron ore reduction and smelting apparatus may further comprise a plasma torch electrode replacement / correction device adapted to automatically replace at least one used / corroded electrode of the plasma torch with a new electrode / correct the used / corroded electrode with at least one new electrode while the torch remains in operation.

[0059] In an AC plasma torch, in particular in a 3-phase AC plasma torch, the electrode generally has a rod shape. During operation, one side of the rod facing the area where plasma is generated degrades and the length of the electrode shortens. The plasma torch includes a feed device that ensures that the inter-electrode distance of the side of the rod facing the area where plasma is generated is maintained by pushing the electrode toward the plasma generation area. After a predetermined minimum length of the electrode, a plasma torch electrode replacement / correction device can replace or correct the electrode.

[0060] The modification of the electrode is achieved by connecting the back side of the electrode (opposite to the side of the electrode facing the area where the plasma is generated) to the new electrode (e.g., by compatible protrusions and receiving openings on the used and new electrodes, which may be compatible threads). The attachment of the new electrode to the old electrode is achieved by an electrode clamping device (clamp). An advantage of the electrode modification device is that the operation of the device is minimally disturbed when modifying the electrode.

[0061] Alternatively or in addition, the iron ore reduction and smelting apparatus may include an electrode paste column or paste feeder. The electrode paste column or paste feeder may be used to modify the graphite electrode with (e.g., carbon) paste. The intense heat and current during plasma operation can cause the graphite electrode to gradually corrode and consume. Such methods of modifying the electrode with paste can at least partially or completely reverse the corrosion or consumption. Carbon paste (usually a mixture of graphite and a binder) is applied to the consumable or worn portion of the electrode.

[0062] This paste replenishes the carbon content, extending the life of the electrode and helping to maintain efficient electrical conductivity and heat transfer during plasma operation.

[0063] The electrode paste column or paste feeder is suitable for introducing carbon paste into the electrode column without interrupting the plasma process.

[0064] The process involves bringing a column of electrode paste to the consumed or corroded portion of the graphite electrode. The column contains a carbon paste mixture which is then gradually pushed into the electrode column. As the paste is introduced, it fills the voids left by the consumed electrode material and restores the carbon content.

[0065] This method allows for controlled and precise addition of carbon paste, ensuring that the performance and efficiency of the electrode is maintained throughout the plasma operation. It helps extend the operating life of the electrode and helps improve the overall efficiency of the plasma operation.

[0066] In a DC plasma torch, the electrode may have a tubular shape. During operation, the side of the tube facing the area where the plasma is generated degrades and the thickness of the electrode shortens. The plasma torch electrode replacement device removes the broken electrode from the plasma torch and places a new electrode into the plasma torch. Replacing the used electrode with a new electrode is achieved by an additional electrode clamping device (clamp).

[0067] The plasma torch electrode replacement / correction device is controlled by a control unit (e.g., a computer device) which determines the state of the electrode in use (e.g., by a suitable camera or electrical characteristics of the plasma torch). When the control unit determines that the minimum length / thickness of the electrode has been reached, the control unit instructs the replacement / correction device to replace or correct the used electrode.

[0068] The plasma torch electrode replacement / repairing device may include a storage station for unused (new) electrodes. The plasma torch electrode replacement / repairing device may also include a storage station for used electrodes. In this way, the plasma torch electrode replacement / repairing device can operate for a predetermined time without human intervention.

[0069] The blast furnace may include a plurality of first gas injectors and / or second gas injectors.

[0070] The blast furnace may comprise at least 10 first gas injectors and up to 70 first gas injectors, most preferably 18 to 40 first gas injectors.

[0071] Furthermore, the blast furnace may comprise at least 10 secondary gas injectors and up to 70 secondary gas injectors, most preferably 18 to 40 secondary gas injectors.

[0072] The plurality of first gas injectors and / or second gas injectors may be arranged substantially equidistantly and / or circularly.

[0073] The outlets of the respective injectors may be evenly distributed with a distance between each other of between 0.5 m and 2.5 m, and preferably between 1.0 m and 1.5 m.

[0074] The iron ore reduction and smelting plant may further comprise at least one sensor adapted to analyse the composition of the gas at the roof.The sensor may be within the roof inside the furnace, or may be connected to a pipe withdrawing gas from the roof of the furnace.

[0075] The sensor may be of electrochemical, catalytic bead (thermocatalytic), photoionization, infrared spot, infrared imaging, semiconductor or ultrasonic type. A semiconductor type sensor may be a metal oxide semiconductor sensor. The sensor may be included in a gas chromatograph.

[0076] The at least one sensor may be adapted to detect CO, CO2 or / and H2 concentrations in the gas. The at least one sensor may also be adapted to detect H2O, N2 or / and CH4 concentrations in the gas.

[0077] The iron ore reduction and smelting equipment may also include a gas injector adjustment device, which is configured to adjust the composition of the gas and / or the volume of the gas injected by the first gas injector and / or the second gas injector based on the determined gas composition and / or temperature at the top layer of the furnace.

[0078] The gas injector regulating device may also adjust the power supply to the at least one electric heater based on the determined gas composition at the furnace top layer and / or the temperature at the furnace top layer.

[0079] The gas injector adjustment device may also be configured to adjust the composition of the gas injected by the first gas injector and / or the second gas injector and / or the volume of the gas and / or the temperature of the gas based on the molten iron production rate and the composition and / or temperature of the molten iron output by the device. In order to determine the molten iron production rate and the composition of the molten iron output by the device, the device also includes a sensor positioned at the molten iron outlet of the furnace, the sensor being configured to determine the composition of the molten iron and determine the volume of the molten iron.

[0080] An advantage of the apparatus as defined above is that oxygen consumption during hot metal production can be reduced and thus CO2 emissions can be reduced.

[0081] Therefore, the iron ore reduction and smelting apparatus may further include an oxygen supply device adapted to inject a gas containing oxygen at a lower amount than a conventional smelting and reduction apparatus. The oxygen supply device may be adapted to inject a gas containing oxygen at a lower amount than 120 Nm 3 / t molten iron, less than 80Nm 3 / t molten iron, less than 40Nm 3 / t molten iron or less than 30Nm 3 / t molten iron is injected with a gas containing oxygen. For example, the oxygen supply device may be adapted to supply oxygen at 1 Nm 3 / t-120Nm 3 / t molten iron, 1Nm 3 / t-80Nm 3 / t molten iron, 1Nm 3 / t-40Nm 3 / t molten iron, 1Nm 3 / t-30Nm 3 / t or 0Nm 3 / tInjects a gas containing oxygen.

[0082] The oxygen-containing gas may contain at least 75% (vol / vol) oxygen, or at least 95% (vol / vol) oxygen. For example, the oxygen-containing gas may contain 75%-99% (vol / vol) oxygen, or 95%-99% (vol / vol) oxygen.

[0083] Optionally, the iron ore reduction and smelting plant comprises means for supplying oxygen into the blast furnace.The means for supplying oxygen are preferably used only during transition phases (eg restarting after a maintenance stop).

[0084] The iron ore reduction and smelting plant may further comprise a gas cleaning device adapted to recycle blast furnace top gas. The gas cleaning device may be connected to the top of the blast furnace via a pipeline. The gas cleaning device may comprise a pressure regulating device to control the pressure at the top of the furnace within the range of 1 barg to 10 barg, more preferably 1.5 barg to 6 barg, most preferably 2 barg to 4 barg. The gas cleaning device is adapted to remove dust, H2O and optionally sulphur, chlorine and / or other undesirable compounds.

[0085] The reducing gas generator may be a gas reformer or a CO2 removal device. It is preferred to use a gas reformer. The reducing gas generator may also be an H2 removal device that provides H2. The removed H2 may be used as reducing gas in the process, and the remainder may be used in the burner. An adsorbent-enhanced water-gas shift reactor that converts CO to H2 may also be part of the reducing gas generator. For example, in combination with an H2 removal device, the H2 recovery rate may be further improved.

[0086] The gas output by the reducing gas generator may include a reducing agent to oxidizing agent ratio (CO+H2) / (CO2+H2O) in % (vol / vol) greater than 7, 8 or 9. The ((CO+H2) / (CO2+H2O)) ratio may be 6-80, 7-30 or 8-12.

[0087] Since those parts of the gas from the top layer which are suitable for providing and / or generating reducing gas are at least partially reused, the amount of reducing gas, in particular hydrogen, which has to be supplied by the first reducing gas generator can be reduced. Thus, the amount of reducing gas required or the components providing the reducing gas can be reduced. Part of the top gas can also be used for burners and / or reforming gas.

[0088] The iron ore reduction and smelting apparatus may be adapted to provide (possibly cleaned / treated) hydrogen-containing top gas to the gas from a gas generator which supplies gas to the second injector (e.g. where its temperature is higher, particularly in non-catalytic reforming for cooling reducing gases entering the shaft injectors).

[0089] The connections between the various devices of the apparatus may be provided by suitable conduits.

[0090] The first reducing gas generator may be a catalytic or non-catalytic reformer, a regenerative reformer without a catalyst, configured to provide the reducing gas at a temperature of 1100° C. or higher.

[0091] The advantage of using such a reformer which provides the reducing gas at a temperature of 1100° C. or higher and provides hydrogen to the reducing gas is that the reducing gas is already preheated to a relatively high temperature before being heated in the first gas injector and / or the second gas injector. In addition, the ((CO+H2) / (CO2+H2O))-ratio is increased compared to catalytic processes operating at lower temperature levels.

[0092] Also disclosed is a method for reducing and melting iron ore in a blast furnace, the method comprising the steps of:

[0093] - Injecting superheated reducing gas at a temperature of 1600°C-2600°C into the furnace at the tuyere layer; wherein the volume flow rate of the reducing gas injected at the tuyere layer is 500Nm 3 / t-1300Nm 3 / t molten iron, and the reducing gas contains 30%-100% (vol / vol) H2, and wherein the coke ratio of the method is lower than 200kg / t molten iron;

[0094] - thereby providing molten iron.

[0095] It has surprisingly been found that the use of the above defined amount of hydrogen in combination with the above defined volume flow of the reducing gas injected at the tuyere layer significantly reduces the coke rate.

[0096] The method may be implemented using the apparatus defined above.

[0097] The method may further include injecting a reducing agent into the furnace at the shaft layer at a temperature of 800°C to 1000°C.

[0098] It has surprisingly been found that the additional injection of a reducing gas as defined above further reduces the coke rate.

[0099] The method may further include injecting reducing gas at the shaft level substantially along the circumference of the blast furnace so that gas rising from the agglomerated area is centrally located within the blast furnace.

[0100] It has surprisingly been found that injection of a reducing gas as defined above reduces the coke ratio.

[0101] The ratio between the volume flow rate of the reducing gas injected at the shaft layer and the volume flow rate of the reducing gas injected at the tuyere layer is 0:1 to 1:1.

[0102] In other words, a ratio of 0:1 covers the situation where no reducing gas is injected at the shaft layer and the reducing gas is injected only at the tuyere layer.

[0103] If reducing gas is additionally injected at the shaft layer, the coke ratio decreases to an optimum value when the amount of gas injected at the tuyere layer is increased. Therefore, the ratio between the volume flow rate of reducing gas injected at the shaft layer and the volume flow rate of reducing gas injected at the tuyere layer is 1:10 to 1:1, 1:5 to 8:10, 1:3 to 7:10, 0.4 to 0.7, or 0.6 to 0.65.

[0104] The method may include not using any auxiliary fuel injection (eg, coal) in performance of the method.

[0105] In the method as defined above, the hydrogen in the reducing gas may comprise hydrogen generated wholly / partially from renewable energy and / or from natural gas reforming with or without carbon capture, and / or wherein the reducing gas is heated and / or superheated using wholly / partial renewable energy and / or lean CO2 electricity such as from nuclear. BRIEF DESCRIPTION OF THE DRAWINGS

[0106] Figure 1 An iron ore reduction plant as disclosed comprising a blast furnace and a first reducing gas generator is shown.

[0107] Figure 2 Shown are areas within the blast furnace and injection locations for various gases that may be injected into the blast furnace.

[0108] Figure 3 The area within a blast furnace is shown. DETAILED DESCRIPTION

[0109] Attached photos

[0110] Figure 1 An iron ore and smelting plant 1 as disclosed in the present application is schematically shown. Each of the elements of the plant, in particular the devices, generators etc., is also disclosed individually. Furthermore, the disclosed plant 1 may comprise any number of the shown devices, generators etc.

[0111] Solid arrows symbolize the direction of airflow within the ducts and the device 1. Dashed arrows symbolize wireless or wired communication lines within the device 1, in particular communication lines to and from the control device.

[0112] The device 1 comprises a blast furnace 2. The blast furnace 2 comprises, from the furnace bottom to the furnace top, a furnace chamber 10, a region including tuyere (ie, tuyere layer 3), a shaft region including a shaft layer 4, and a furnace top layer 5.

[0113] A first gas injector 6 is mounted on the tuyere layer 3. The first gas injector 6 is used to inject reducing gas into the blast furnace 2. The tuyere layer 3 (or area) can also be used to inject oxygen into the blast furnace 2 via the oxygen supply device 11.

[0114] The first gas injector may comprise an electrically driven heater, preferably a plasma torch (not shown).

[0115] The lock hopper 8 is used to supply materials (e.g. coke, ore and optional flux) to the interior of the blast furnace while ensuring that the pressure conditions in the blast furnace 2 are maintained. On the shaft layer 4, the blast furnace may also include at least one second gas injector 9, which can be used to inject reducing gas into the shaft layer / area.

[0116] Both the first injector 6 and the second injector 9 can receive reducing gas from the reducing gas generator 7. The reducing gas generator 7 can be a synthesis gas generator. The reducing gas provided by the reducing gas generator 7 can contain 30%-100% (vol / vol) of hydrogen. The reducing gas can be produced by the reducing gas generator 7 from natural gas, coke oven gas or another hydrocarbon source. The reducing gas generator 7 can also use hydrogen provided by a local or remote hydrogen storage device, and can be green or blue hydrogen. Hydrogen can be obtained using an electrolyzer. Alternatively, the reducing gas generator can also produce reducing gas by separating H2O and / or CO2 from a gas rich in H2 and / or CO as a furnace top gas, BOF gas or other gas. Common or separate reducing gas generators can be used for the tuyere layer and the furnace body layer. The separate reducing gas generators can be of the same or different types.

[0117] The gas present in the furnace top layer may be continuously or intermittently withdrawn from the furnace top layer 5 of the melting furnace 2. The gas withdrawn from the furnace top layer may be recycled by removing some components such as water components, chlorine components, sulfur components such as COS, or / and heavy metals using a gas cleaning device 12 and an optional gas preparation device (not shown). The gas treated by the gas cleaning device 12 (and the optional gas preparation device) may be supplied to the reducing gas generator 7 or supplied to the path leading to the injector at the furnace shaft layer 4 (after the reducing gas generator 7). At this location, supplying clean BOF gas is also very advantageous because its reduction degree is high.

[0118] The gas can be analyzed by the sensor 13 which is in contact with the retrieved gas. Figure 12 is shown as being located at the end of a pipe connected to the furnace 2, but the sensor 13 may also be arranged in the furnace or any other pipe, accessible to the gas withdrawn from the furnace top 5. After gas cleaning and water removal, a further sensor 17 may be provided, at least a humidity and / or temperature sensor, since the water content in the gas may be a relevant factor for the stoichiometric control of the mixed gas (hydrocarbon source and top gas) entering the gas reformer. The sensor 13 and / or 17 provides data to the gas injector regulating device 14. The gas injector regulating device 14 comprises a circuit with a memory, which is capable of processing the data provided by the sensor 13 and sending a signal to the first gas injector 6 or / and the second gas injector 12, the reducing gas generator 7 and / or the gas cleaning device 12. For example, the gas output from the reducing gas generator or the gas cleaning device 12, the composition and temperature of the gas output may be adjusted accordingly. For example, the gas temperature provided by the gas injector may be adjusted by increasing / or decreasing the power supplied to the plasma torch. The gas injector regulating device 14 may also process inputs from other sensors, such as sensors checking the quality of the molten iron or the rate of production of the molten iron. Based on the data provided by the sensors, the gas injector regulating device 14 may modify the composition of the gas produced by the gas generator 7 or the conditions (e.g., temperature, pressure, volume flow) applied to the first gas injector 6 and / or the second gas injector 9.

[0119] The gas pressure can be measured by a sensor 16 in contact with the withdrawn gas. Figure 1 1 is shown at the end of a pipe connected to the furnace 2, but the sensor 16 may also be arranged in the furnace or any other pipe with access to the gas withdrawn from the furnace roof 5. The sensor 16 provides data to a pressure regulating device included in the gas cleaning device 12.

[0120] Figure 2 Shown are areas within the blast furnace and injection sites for the various gases that may be injected into the furnace.

[0121] The material in the operating furnace 2 comprises from the top to the bottom of the furnace a shaft region 22 and a cohesion region 23. The shaft region 22 and the cohesion region 23 comprise alternating material layers consisting of ore 29 and coke 21. Following the cohesion region 23 is a dripping region 24 which comprises a raceway 25 near the tuyere.

[0122] At the tuyere layer 28, reducing gas, oxygen and / or hot air can be injected into the furnace 2. At the shaft layer 27, reducing gas can be optionally injected into the furnace 2. The shaft layer 27 can also be considered as a layer where the stacking angle of the belly 15 changes from 0° to a value different from 0°. Alternatively, the shaft layer is a layer starting from the root of the cohesive area 23.

[0123] Reference Examples and Examples of the Present Disclosure

[0124] In order to better illustrate the present disclosure, several cases were investigated in depth. The details of these cases are presented in Table 1.

[0125] Case 1 and 2

[0126] Cases 1 and 2 are currently operating reference plants, where the crude coke ratios are 255 kg / tHM and 205 kg / tHM, respectively.

[0127] Cases 3 and 4 are reference devices for injecting hot hydrogen into the tuyere without injecting hot hydrogen into the furnace body and injecting hot hydrogen into the tuyere and into the furnace body, respectively.

[0128] Cases 5 and 6 are new furnaces (plants including furnaces of the present disclosure) with coke rates of 180 kg / tHM and nearly 100 kg / tHM, using superheated syngas injection at the tuyere layer.

[0129] Cases 7 and 8 are about new furnaces (including equipment of other furnaces of the present disclosure) having coke rates of 180 kg / tHM and 100 kg / tHM, using superheated syngas injection at the tuyere layer, and in addition, injecting hot syngas into the furnace shaft.

[0130] Case 1 represents a typical well-functioning blast furnace with high pulverized coal injection, several of which can be found all over the world, and in particular in Europe.Pulverized coal injection (PCI) allows to reduce the lump coke rate or raw coke rate to values ​​of about 250 kg / t HM.

[0131] It can be seen that this furnace requires about 235Nm per ton of molten iron. 3 The total oxygen. Part of the oxygen comes from heated air, and part of it comes from enriched oxygen, where pure oxygen comes from air separation equipment.

[0132] This oxygen enrichment is necessary because the blast furnace requires a certain flame temperature to function properly. In fact, the flame temperature ensures that the reduced ore can be melted and the injected coal can be burned in the raceway. For PCI injection, the required flame temperature is about 2200°C.

[0133] Case 2 represents a typical blast furnace reaching an abnormally high PCI injection. Such operation has been continued for a long production period of several months. However, this operation is very challenging and requires high operating skills and very good raw materials, specifically high quality expensive coke.

[0134] If the injection conditions at the tuyere are compared, it can be seen that the oxygen enrichment must be further increased, but in general the conditions at the tuyere, the hot blast temperature and the gas volume flow rate, do not change dramatically.

[0135] Both operations are of course undesirable if one wants to reduce CO2 emissions from hot metal production, since the entire energy and reducing agent input is coal based.

[0136] Case 3 and 4

[0137] In these reference cases, the operation of the blast furnace is analyzed using high hydrogen injection rates to reduce part of the energy and reducing agent input from coal and to use CO2-free hydrogen.

[0138] It is known that hydrogen cannot be injected in large quantities if injected cold at the tuyere together with oxygen-enriched hot blast. The typical maximum amount of hydrogen used is limited to less than 30 kg / t HM.

[0139] Therefore, the addition of hydrogen requires changes. It requires hot injection, either only at the tuyere level or at both the tuyere level and the furnace shaft level.

[0140] As injection temperature we assume 950°C for the shaft layer and 1200°C for the tuyere layer.

[0141] These are the temperature levels that are typically achievable when using conventional heat exchangers and regenerative heaters.

[0142] At the tuyere layer, cold oxygen now needs to be added in order to burn some of the coke for reaching the flame temperature required for melting the ore. It is known from furnaces that do not use PCI injection but natural gas injection, in which case the flame temperature can be reduced to a minimum of about 1800°C-1850°C, always requiring sufficient flow to supply enough energy for melting the reduced ore and to supply energy for heating and reducing the ore in the blast furnace shaft.

[0143] It can be seen that the oxygen injection at the tuyere can be increased from about 240Nm 3 / t HM reduced to 150Nm 3 / t HM and 180Nm 3 / t HM. Therefore, less carbon can be burned at the tuyere. However, due to the absence of carbon obtained from PCI injection, more coke needs to be burned at the tuyere than in Cases 1 and 2, resulting in an increase in the coke ratio.

[0144] By the way, carbon is the only element contained in typical fuels that can burn with oxygen under tuyere conditions to form CO and thus heat the injected gas. CO2 and H2O cannot form under the reducing conditions we find at the tuyere. If CO2 and / or H2O are present in the injected gas, it will have the adverse effect that the coke will be consumed by endothermic gasification, resulting in a decrease in the flame temperature.

[0145] When using hydrogen in a blast furnace, the conflict between the additional coal / coke demand and the desired reduction in CO2 emissions cannot be overcome by conventional means.

[0146] In addition, it can be seen that in both cases with and without furnace body injection, pure hydrogen injection will require a large amount of hydrogen, with and without furnace body injection, each ton of molten iron requires 1070Nm 3 and 1280Nm 3 This far exceeds the hydrogen requirements of other production routes, such as the direct reduction process, which requires about 660 Nm3 / t HM hydrogen. In addition, the coke rate required in these cases is quite high, making it uninteresting.

[0147] To overcome this problem, it is proposed to inject synthesis gas with or without the addition of pure hydrogen into the blast furnace at superheat temperature.

[0148] Superheating can be accomplished, for example, by means of a plasma torch.

[0149] Cases 5 and 6 :

[0150] In these cases, the advantage of superheating the gas injected at the tuyere layer is that we now do not need to burn the coke with oxygen to reach the temperature levels required to melt the reduced ore at the tuyere.

[0151] Cases 7 and 8 :

[0152] Compared to Cases 5 and 6, these cases have additional syngas injection into the furnace shaft.

[0153] When operating the furnace, gas is partially injected into the furnace shaft to provide the temperature level required for melting with a lower plasma torch power demand. In addition, by injecting through the furnace shaft, less gas needs to pass through the high resistance cohesion area.

[0154] It can be seen that it is now possible to achieve very low coke rates, approximately 180 kg / t hm and 100 kg / t hm in the two examples respectively.

[0155] At 440Nm 3 In the case of 100 kg / thm coke per tonne of carbon, the amount of hydrogen added is also very low.

[0156] By recycling the blast furnace top gas back to the blast furnace via a reducing gas generator, the addition of hydrogen can be reduced.

[0157] To this end, it is necessary to reduce the content of dust, H2O and CO2. Dust can be reduced in dry or wet gas cleaning systems. In the case of a wet gas cleaning system, a portion of the H2O will also be removed. If necessary, the H2O can be easily further reduced by cooling and condensing (e.g., by a condenser, quenching, etc.). Other removal systems can be used to treat unwanted components such as oxygen, chlorine, sulfur components such as COS, heavy metals, etc. CO2 elimination can be achieved by any CO2 removal technology, such as MEA, pressure swing adsorption (PSA), vacuum pressure swing adsorption (VPSA) and reforming CO2 with hydrocarbons to form CO and hydrogen.

[0158] In this embodiment, reforming with natural gas has been applied.

[0159] Reforming can be done catalytically at temperatures of about 950°C, or without a catalyst in a regenerative reformer type at high temperatures >1100°C.

[0160] The latter type is very suitable for preparing the gas at the tuyere layer, since very high temperatures are desired specifically at the tuyere layer.

[0161] Furthermore, when reforming the gas at high temperatures, very high gas reductions can be achieved, (CO+H2) / (CO2+H2O)>7, preferably>8, more preferably>9. High reductions are very important for achieving low coke ratios, because every CO2 and H2O injected into the gas at the tuyere will consume coke in the cyclone and reduce the flame temperature.

[0162] The injection of CO2 and H2O at the furnace shell layer will reduce the degree of direct reduction of the ore into the agglomeration zone, so the coke needs to be fully reduced in the direct reduction zone.

[0163] Table 1 :

[0164]

[0165]

[0166] Since we wish to discuss the effects of several gases generated or injected into the furnace on key issues, it is best to describe them as follows: Figure 2 It is introduced and its location is indicated below to avoid any misunderstanding.

[0167] The following table summarizes the volume flow rates of these gases:

[0168] Table 2 :

[0169]

[0170]

[0171] Coke consumption

[0172] The coke in the plant is consumed by solution loss reactions in the furnace shaft, carburization, liquid direct reduction (upper part of the drip zone) and coke gasification / combustion in the tuyere. In addition, a small amount of coke fines is captured by the top gas.

[0173] In the table below, the amount of coke consumed by the described means is presented for all cases.

[0174] Table 3: Coke redistribution for all cases

[0175]

[0176] It can be seen that the coke consumption for liquid direct reduction in the new furnace is significantly lower. The reason is that the iron-containing charge is reduced to a very high degree in the furnace shaft due to the very high ratio of reducing agent to oxidizing agent in the furnace. Therefore, less FeO is reduced to Fe through direct reduction and dissolution reactions. For Cases 5-8, the coke consumption for direct reduction is less than 20 kg / tHM, while for the conventional furnace, the coke consumption is more than 70 kg / tHM.

[0177] It can also be seen that the reducing gas injected into the furnace shaft limits the coke consumption by solution losses in Cases 7 and 8. Therefore, it is considered that the injection of reducing gas does not lead to an increase in the coke quality requirement for the new furnace conditions.

[0178] Furthermore, since the superheated reducing gases carry a large amount of heat energy into the plant, the demand for the amount of coke burned in the tuyere is reduced.

[0179] What is described herein shows how the coke rate can be reduced to very low levels using superheated reducing gas injected into the tuyere and optionally hot reducing gas injected into the shaft layer.

[0180] airflow

[0181] It is known that blast furnaces have been successfully operated at a crude coke ratio of 210 kg / t HM, using high pulverized coal injection rates, fed with hot blast (hot air) highly enriched with oxygen.

[0182] The oxygen consumes the injected coal and coke, thereby providing the energy to heat the tuyere gases to the high temperature levels required to melt the reduced ore in the raceway.

[0183] To reduce CO2 emissions from blast furnaces, it is desirable to eliminate injected coal and reduce the coke rate as much as possible.

[0184] To this end, the total amount of oxygen injected into the tuyere needs to be reduced to a low level, preferably below 120 Nm 3 / tHM.

[0185] In order to provide energy for melting and reducing the ore at high temperature levels, the tuyere gas volume flow rate can be reduced only slightly by about 20% compared to conventional melting and reduction plants if typical raceway temperatures of 1800°C to 2600°C are to be maintained.

[0186] Since reducing gases are no longer generated inside the raceway of the blast furnace, or at least no longer generated to a small extent, it is necessary to generate reducing gases externally and to supply them to the furnace.

[0187] Table 4 shows the total mass flow rate injected into the furnace for all studied cases. It is obvious that this value is significantly lower for the new furnace compared to the conventional furnace due to the amount of hydrogen in the gas. The composition of the gas injected into the tuyere for all cases is presented in Table 5.

[0188] When the coke ratio is very low, below 200 kg / t HM, in order not to exceed the acceptable hydrodynamic conditions in the cohesive zone, we claim that this requirement can only be achieved if the gas mass flow rate injected at the tuyere is kept below 800 kg / t HM (see Table 4).

[0189] To this end, the hydrogen content of the gas injected at the tuyere layer must be higher than 30%. It should be mentioned that although the total mass flow rate in the case of pure hydrogen (100%) is lower than our case, the coke rate is as high as 274kg / tHM and 324kg / tHM.

[0190] Table 4: Gas mass injected into the tuyere

[0191]

[0192] Table 5: Gas composition of the reducing gas injected into the tuyere .

[0193]

[0194]

[0195] In order to estimate the effect of such lower coke ratios on the cohesion zone pressure drop, parameters of the gas entering the cohesion zone (CZ) (bosh gas) are required. Bosh gas is the result of gas injection into the tuyere, coke combustion (if O2 is injected), coke gasification (if H2O and CO2 are present), and production of liquid CO (FeO(l) + C(s) → Fe(l) + CO) and non-iron oxides (SiO2, MnO, P2O3, etc.) by final reduction reactions.

[0196] The inventors surprisingly found that by injecting part of the gas into the shaft of the furnace, the volume of gas passing through the cohesive zone can be reduced. This can be seen in Cases 7 and 8 with shaft injection, where the volume of gas traveling through the CZ is significantly reduced for the new equipment.

[0197] Table 6: Bosh gas conditions and estimated pressure drop travelling through the CZ for all cases .

[0198]

[0199]

[0200] To estimate the pressure drop above the CZ, we assume that the ore layer is impermeable. In addition, it is believed that a portion of the slag penetrates into the coke layer of the CZ and blocks a portion of the coke layer. This coke-ore interface layer is also considered to be impermeable in thickness. Therefore, all rising gases pass only through the CZ coke layer, as Figure 3 shown.

[0201] For the embodiments of running BF (cases 1 and 2), the coke layer thickness excluding the interface layer was 15 cm. It was assumed that the thickness of the interface layer was 4 cm. Since the coke layer thickness is an important factor for stable furnace operation, this value remains unchanged in all cases. Advantageously, the minimum coke layer thickness is at least 10 cm (9 cm-11 cm) or at least 15 cm (14 cm to 16 cm). The material feed device can be adjusted to provide the desired thickness.

[0202] As the coke ratio decreases, the total passing area of ​​the gas in the cohesion area becomes smaller. In order to keep the pressure drop in the cohesion area within an acceptable range, the volume flow rate and density of the furnace gas should be reduced.

[0203] It can be seen from Table 6 that the pressure drop in the CZ of Case 2 is much higher than that of Case 1 due to the lower coke ratio.

[0204] For a coke rate of 180 kg / t HM, the new equipment works well because the bosh gases travel more smoothly through the CZ. However, reducing the coke rate to the final value of 100 kg / t HM without shaft injection is challenging because the pressure drop in the CZ is quite high. This means that for Case 6, the risk of flooding and hanging charge is higher.

[0205] This problem can be solved by increasing the pressure of the injected gas. Higher tuyere gas pressure increases density and reduces the velocity of the gas entering the furnace. Velocity has a much greater effect on pressure drop than density, since pressure drop is related to the square of velocity. However, higher pressures require more expensive mechanical devices and higher electrical power requirements.

[0206] However, this challenge can be mitigated by shaft injection, which results in a lower volume flow rate of injection gas into the tuyere, resulting in a lower pressure drop. It can be clearly seen that the pressure drop for Case 8 (new furnace) is even lower than that for Case 2.

[0207] Furthermore, the lower pressure drop in the CZ and drip zone of the new equipment allowed us to increase the productivity. This was achieved by the effect of hydrogen on the gas density, which provided the desired pressure drop. To achieve the pressure drop level of the conventional equipment (Case 2), the productivity could be increased by 15%. Thus, the advantages of furnace shaft injection were once again demonstrated in Case 8.

[0208] The table below shows the pressure drop for Case 8 with lower and higher production rates.

[0209] Table 7 :

[0210]

[0211] Plasma Torch

[0212] The plasma torch disclosed in the present application may be a DC plasma torch or an AC plasma torch.

[0213] An AC 3-phase plasma torch may show the following characteristics.

[0214] The core of the plasma can reach about 15000K or even higher.

[0215] Most preferably, graphite electrodes having an outer diameter of 50 mm to 200 mm, 100 mm to 150 mm, or 130 mm may be used.

[0216] An AC voltage of 100V-1500V may be applied. It is worth noting that such voltages may also be applied to DC torches. Higher voltages, such as kV, may also be applied to achieve higher power outputs, such as 2MW-8MW.

[0217] The inter-electrode distance of the plasma torch is adjustable (0mm-100mm or 40mm gap is possible, a larger gap of 100mm is also possible). The adjustability allows for easy plasma ignition and higher plasma stability.

[0218] Plasma control can be based on visual observation: using relevant software, the plasma pictures captured continuously by the camera are compared with the steady-state plasma pictures for baseline comparison. Then, corresponding changes (i.e., inter-electrode distance, voltage amplitude, etc.) are applied in order to keep the plasma in a stable state.

[0219] If spare electrodes are continuously charged in the electrode storage station, the plasma torch can be operated for weeks or months.

[0220] Six arc plasmas are generated each time between three electrodes that alternately play the role of anode and cathode.

[0221] The alternating ignition points of the plasma make it more diffusive, resulting in higher gas volume processing than a DC plasma torch. Perhaps 30% more gas can be processed in a single pass.

[0222] If the reducing gas has a low concentration of oxidizing species, i.e. H2O and CO2, the lifetime of the electrode (particularly in the case of graphite electrodes) can be increased. The reducing gas may comprise a ratio of reducing agent to oxidizing agent (CO+H2) / (CO2+H2O) in % (vol / vol) greater than 7, 8 or 9. The ((CO+H2) / (CO2+H2O)) ratio may be 6-80, 7-30 or 8-12.

[0223] Therefore, a minimum degree of reduction of the gas should be maintained and / or the concentration of H2O plus CO2 should be limited to values ​​below 35 vol%, 10 vol%, preferably below 5 vol%.

[0224] Example

[0225] The following embodiments are also provided:

[0226] Embodiment 1. An iron ore reduction and melting device, the iron ore reduction and melting device comprising:

[0227] - a furnace, the furnace comprising from the furnace bottom to the furnace top: a furnace chamber, a tuyere layer, a furnace body layer and a furnace top layer, the furnace comprising at least one first gas injector on the tuyere layer

[0228] - At least one reducing gas generator, said at least one reducing gas generator being connected to said at least one first injector, wherein said first injector is suitable for providing reducing gas on said tuyere layer and is suitable for operating at a coke ratio of less than 200 kg / t molten iron, said reducing gas containing 30%-100% (vol / vol) hydrogen, having a density of 0.15 kg / Nm3-0.85 kg / Nm3 and a mass flow rate of 300 kg / tHM to 800 kg / tHM or / and a volume flow rate of 500 Nm3 / tHM-1300 Nm3 / tHM.

[0229] Embodiment 2. According to the iron ore reduction and smelting equipment of embodiment 1, the iron ore reduction and smelting equipment further comprises at least one second gas injector located on the furnace shaft layer.

[0230] Embodiment 3. The iron ore reduction and smelting apparatus according to embodiment 1 or 2, wherein the at least one first gas injector comprises at least one electrically driven heater.

[0231] Embodiment 4. An iron ore reduction and smelting device according to any one of the preceding embodiments, wherein the at least one first gas injector is suitable for heating the reducing gas to 1600℃-2600℃, preferably 2100℃-2200℃, injecting the reducing gas into the blast furnace at a volume flow rate of 500Nm3 / t-1300Nm3 / t of molten iron, injecting the reducing gas at an absolute pressure of at least 2 bar up to 10 bar, preferably 4 bar to 5 bar, or / and the at least one electrically driven heater of the at least one first gas injector is suitable for operating at an electrical power of 200kwh / t-600kwh / t of molten iron.

[0232] Embodiment 5. The iron ore reduction and smelting apparatus according to embodiment 3, wherein the heater is a plasma torch, and the plasma torch is a plasma torch including an electrode or without an electrode.

[0233] Embodiment 6. An iron ore reduction and melting equipment according to Embodiment 5, wherein the plasma torch is a plasma torch comprising an electrode, and the iron ore reduction and melting equipment further comprises a plasma torch electrode replacement / correction device, the plasma torch electrode replacement / correction device being suitable for automatically replacing at least one used or corroded electrode of the plasma torch with an unused electrode / correcting the used electrode with at least one new electrode, the plasma torch electrode replacement / correction device comprising a storage table for unused electrodes.

[0234] Embodiment 7. The iron ore reduction and smelting equipment according to embodiment 5, wherein the plasma torch is an AC plasma torch, more preferably a 3-phase AC plasma torch, having 3 or multiples of 3 electrodes; or wherein the plasma torch is a DC plasma torch having 2 or multiples of 2 electrodes.

[0235] Embodiment 8. An iron ore reduction and smelting device according to any one of the preceding embodiments, wherein the blast furnace comprises a plurality of first gas injectors and / or second gas injectors, and wherein the plurality of first gas injectors and / or second gas injectors are arranged substantially equidistantly and / or circularly, wherein optionally the outlets of the corresponding injectors are independently and evenly distributed from each other, and the distance between each other is between 0.5m and 2.5m, and preferably between 1.0m and 1.5m.

[0236] Embodiment 9. According to any one of the preceding embodiments, the iron ore reduction and smelting equipment further comprises a sensor, wherein the sensor is suitable for analyzing the composition of the gas at the top layer of the furnace with respect to the CO, CO2, H2 concentration of the gas, and optionally is also suitable for analyzing the composition of the gas with respect to the H2O, N2 or CH4 concentration in the gas, or / and further comprises a temperature sensor suitable for measuring the temperature of the gas at the top layer of the furnace; and / or further comprises a sensor for humidity measurement after gas cleaning and pretreatment.

[0237] Example 10. According to the iron ore reduction and melting equipment described in Example 9, the iron ore reduction and melting equipment also includes a gas injector adjustment device, which is configured to adjust the composition of the gas injected by the first gas injector and / or the second gas injector and / or the volume of the gas based on the determined gas composition at the top layer of the furnace, and is optionally configured to adjust the composition of the gas and / or the volume of the gas based on the molten iron productivity and the composition of the molten iron output by the equipment.

[0238] Embodiment 11. According to any one of the aforementioned embodiments, the iron ore reduction and melting equipment also includes an oxygen supply device, which is suitable for injecting oxygen into the blast furnace at less than 120Nm3 / t molten iron, less than 80Nm3 / t molten iron, less than 40Nm3 / t molten iron, less than 30Nm3 / t molten iron, and 0Nm3 / t molten iron.

[0239] Embodiment 12. According to any one of the preceding embodiments, the iron ore reduction and smelting equipment further comprises a gas cleaning device, wherein optionally the gas cleaning device is suitable for controlling the top pressure of the furnace and / or recycling the top gas of the blast furnace.

[0240] Embodiment 13. An iron ore reduction and smelting apparatus according to embodiment 12, adapted to provide hydrogen to the gas from the gas generator and to supply the gas to the second injector, and / or adapted to add hydrogen upstream or to an inlet of the reducing gas generator.

[0241] Example 14. An iron ore reduction and smelting equipment according to Example 13, wherein the reducing gas generator includes a CO2 separation device and / or a catalytic reformer, and / or a non-catalytic reformer, preferably a regenerative reformer without a catalyst, which is configured to provide reducing gas at a temperature of 1100°C or higher; wherein optionally the reducing gas generator is configured to provide reducing gas to the tuyere layer, the furnace body layer or both, and the reducing gas generators for the tuyere layer and the furnace body layer may be different.

[0242] Example 15. A method for reducing and melting iron ore in a furnace, the method comprising the following steps:

[0243] - injecting a superheated reducing agent at a temperature of 1600°C-2600°C into the furnace at the tuyere layer; wherein the volume flow rate of the reducing gas injected at the tuyere layer is 500Nm3 / t-1300Nm3 / t molten iron and the reducing gas contains 30%-100% (vol / vol) H2, has a density of 0.15kg / Nm3-0.85kg / Nm3 and a mass flow rate of 300kg / tHM to 800kg / tHM or / and wherein the coke ratio of the method is lower than 200kg / t molten iron;

[0244] - thereby providing molten iron.

[0245] Embodiment 16. The method according to embodiment 15, further comprising injecting a reducing agent into the furnace at a temperature of 800°C-1000°C at the shaft layer.

[0246] Embodiment 17. The method according to embodiment 16, wherein the reducing gas is injected at the shaft level substantially along the circumference of the furnace so that the gas rising from the cohesive area is located at the center of the furnace.

[0247] Embodiment 18. A method for reducing iron ore in a blast furnace according to any one of Embodiments 15 to 17, wherein the ratio between the volume flow rate of the reducing gas injected at the shaft layer and the volume flow rate of the reducing gas injected at the tuyere layer is 0:1 to 1:1, preferably 0.6 to 0.65.

[0248] Embodiment 19. A method according to embodiments 15 to 18, wherein the hydrogen in the reducing gas comprises hydrogen generated entirely / partially from renewable energy and / or generated by natural gas reforming with carbon capture, and / or wherein the reducing gas is heated and / or superheated using entirely / partial renewable energy and / or lean CO2 electricity such as from nuclear.

[0249] Embodiment 20. The method according to embodiments 15 to 19, wherein recycled top gas and / or other steelmaking gases are integrated into the mixed gas of the reducing gas generator after treatment in a gas cleaning device or without treatment.

[0250] Example 21. A method according to Examples 15 to 20, wherein the reducing gas generator includes PSA, VPSA, MEA or other CO2 separation technology, and a reducing gas compression and heating device, wherein the device can be arranged in different configurations, preferably compression, separation and heating.

[0251] Embodiment 22. The method according to embodiments 15 to 21, wherein the method comprises catalytic reforming and / or non-catalytic reforming.

[0252] Embodiment 23. The method according to embodiments 15 to 22, wherein the reducing gas generator and / or the gas cleaning device are at least partially fed with cold hydrogen.

[0253] Embodiment 24. The method according to embodiments 15 to 23, wherein the minimum coke layer thickness is at least 10 cm, such as 9 cm-11 cm, or at least 15 cm, such as 14 cm to 15 cm.

[0254] Reference numerals

[0255] 1: Iron ore reduction and smelting equipment

[0256] 2: Blast furnace

[0257] 3: Air outlet layer

[0258] 4: Furnace body layer

[0259] 5: Top floor of furnace

[0260] 6: First gas injector

[0261] 7: Reduction gas generator

[0262] 8: Lock hopper

[0263] 9: Second gas injector

[0264] 10: Furnace

[0265] 11: Oxygen supply device

[0266] 12: Gas cleaning device

[0267] 13: Gas sensor

[0268] 14: Gas injector adjustment device

[0269] 15: Furnace belly

[0270] 16, 17: Sensor

[0271] 21: Coke layer

[0272] 22: Furnace area with stacking

[0273] 23: Cohesive Area

[0274] 24: Drip Area

[0275] 25: Swirling zone where gas is injected through the tuyere

[0276] 26: Dead Iron

[0277] 27: Furnace injection point for reducing gas

[0278] 28: Injection point of oxygen, hot air and / or reducing gas

[0279] 29: Materials containing ores in various processed forms

Claims

1. An iron ore reduction and melting device, the iron ore reduction and melting device comprising: - a furnace, the furnace comprising from the furnace bottom to the furnace top: a furnace chamber, a tuyere layer, a furnace body layer and a furnace top layer, the furnace comprising at least one first gas injector on the tuyere layer - at least one reducing gas generator connected to said at least one first injector, wherein said first injector is adapted to provide reducing gas on said tuyere layer and is adapted to operate at a coke ratio below 200 kg / t of hot metal, said reducing gas comprising 30%-100% (vol / vol) hydrogen, having a relative humidity of 0.15 kg / Nm 3 -0.85kg / Nm 3 Density and mass flow rate from 300kg / tHM to 800kg / tHM or / and 500Nm 3 / tHM-1300Nm 3 / tHM volume flow rate.

2. The iron ore reduction and smelting apparatus according to claim 1, further comprising at least one second gas injector located on the shaft layer.

3. An iron ore reduction and smelting apparatus according to claim 1 or 2, wherein the at least one first gas injector comprises at least one electrically driven heater.

4. An iron ore reduction and smelting apparatus according to any one of the preceding claims, wherein the at least one first gas injector is adapted to heat the reducing gas to 1600-2600°C, 1800-2600°C, 2000-2600°C or 2100-2200°C.

5. An iron ore reduction and smelting plant according to any one of the preceding claims, wherein the at least one first gas injector is adapted to inject gas at a rate of 500 Nm 3 / t-1300Nm 3 The reducing gas is injected into the blast furnace at a volume flow rate of / t molten iron.

6. An iron ore reduction and smelting plant according to any one of the preceding claims, wherein the at least one first gas injector is adapted to inject the reducing gas at a pressure of at least 2 bar up to 10 bar absolute, preferably 4 to 5 bar absolute.

7. An iron ore reduction and smelting apparatus according to any one of the preceding claims, wherein the at least one electrically driven heater of the at least one first gas injector is adapted to operate at an electrical power of 200 kwh / t - 600 kwh / t molten iron.

8. The iron ore reduction and smelting apparatus according to claim 3, wherein the heater is a resistance heater.

9. The iron ore reduction and smelting apparatus according to claim 3, wherein the heater is a plasma torch, and the plasma torch is a plasma torch including an electrode or without an electrode.

10. The iron ore reduction and smelting apparatus according to claim 9, wherein the plasma torch is an electrode-containing plasma torch, and the iron ore reduction and smelting apparatus further comprises a plasma torch electrode replacement / correction device, the plasma torch electrode replacement / correction device being adapted to automatically replace at least one used or corroded electrode of the plasma torch with an unused electrode / correct the used electrode with at least one new electrode; or / and wherein the plasma torch is an electrode-containing plasma torch, and the iron ore reduction and smelting apparatus further comprises an electrode paste column or a paste feeder.

11. The iron ore reduction and smelting apparatus of claim 10, wherein the plasma torch electrode replacement / repairing apparatus further comprises a storage table for unused electrodes.

12. The iron ore reduction and smelting apparatus according to claim 9, wherein the plasma torch is an AC plasma torch, more preferably a 3-phase AC plasma torch, having 3 or multiples of 3 electrodes; or wherein the plasma torch is a DC plasma torch having 2 or multiples of 2 electrodes.

13. The iron ore reduction and smelting apparatus according to claim 9, wherein the plasma torch has a rated electrical power of 1 MW to 10 MW, preferably 2 MW to 6 MW, most preferably 4 MW to 5 MW.

14. The iron ore reduction and smelting apparatus according to claim 9, wherein the plasma torch is an electrodeless plasma torch selected from the group consisting of an induction ignition plasma torch, a microwave plasma torch, a radio frequency plasma torch, or a combination thereof.

15. An iron ore reduction and smelting apparatus according to any one of the preceding claims, wherein the blast furnace comprises a plurality of first gas injectors or / and second gas injectors, and wherein the plurality of first gas injectors and / or second gas injectors are arranged substantially equidistantly and / or circularly, wherein optionally the outlets of the respective injectors are independently and evenly distributed with a distance between each other of between 0.5 m and 2.5 m, and preferably between 1.0 m and 1.5 m.

16. An iron ore reduction and smelting device according to any one of the preceding claims, further comprising a sensor suitable for analyzing the composition of the gas at the top layer of the furnace in terms of its CO, CO2, H2 concentrations, optionally also suitable for analyzing the composition of the gas in terms of its H2O, N2 or CH4 concentrations, or / and further comprising a temperature sensor suitable for measuring the temperature of the gas at the top layer of the furnace; and / or further comprising a sensor for humidity measurement after gas cleaning and pretreatment.

17. The iron ore reduction and melting equipment according to claim 16, further comprising a gas injector adjusting device, wherein the gas injector adjusting device is configured to adjust the composition of the gas injected by the first gas injector and / or the second gas injector and / or the volume of the gas based on the determined gas composition at the top layer of the furnace, and is optionally configured to adjust the composition of the gas and / or the volume of the gas based on the molten iron productivity and the composition of the molten iron output by the equipment.

18. An iron ore reduction and smelting apparatus according to any one of the preceding claims, further comprising an oxygen supply adapted to supply oxygen at a rate of less than 120 Nm 3 / t molten iron, less than 80Nm 3 / t molten iron, less than 40Nm 3 / t molten iron, less than 30Nm 3 / t molten iron, 0Nm 3 / t molten iron injects oxygen into the blast furnace.

19. The iron ore reduction and smelting apparatus according to any one of the preceding claims, further comprising an oxygen supply device configured to inject oxygen at the tuyere layer of the smelting furnace via an oxygen injection port.

20. The iron ore reduction and smelting apparatus according to claim 19, wherein the oxygen injection port is arranged in the first injector.

21. An iron ore reduction and smelting plant according to any one of the preceding claims, further comprising a gas cleaning device, wherein optionally the gas cleaning device is adapted to control the top pressure of the furnace and / or to recycle top gas of the blast furnace.

22. An iron ore reduction and smelting plant according to claim 21, adapted to provide hydrogen to the gas from the gas generator and to supply the gas to the second injector and / or to add hydrogen upstream or to the inlet of the reducing gas generator.

23. The iron ore reduction and smelting equipment according to claim 22, wherein the reducing gas generator comprises a CO2 separation device or / and a catalytic reformer, or / and a non-catalytic reformer, preferably a regenerative reformer without a catalyst, which is configured to provide reducing gas at a temperature of 1100°C or higher; wherein optionally the reducing gas generator is configured to provide reducing gas to the tuyere layer, the furnace body layer or both, and the reducing gas generators for the tuyere layer and the furnace body layer may be different.

24. An iron ore reduction and smelting apparatus according to any one of the preceding claims, wherein the first injector is adapted to provide a density of less than 0.80 kg / Nm 3 , preferably less than 0.60kg / Nm 3 And most preferably less than 0.30kg / Nm 3 at least one reducing gas.

25. An iron ore reduction and smelting plant according to any one of the preceding claims, wherein the first injector is adapted to inject the at least one reducing gas at a total mass flow rate below 800 kg / t HM, preferably below 775 kg / t HM and more preferably below 750 kg / t HM.

26. An iron ore reduction and smelting plant according to any one of the preceding claims, further comprising at least one hydrogen content controller for supplying reducing gas to the first injector, and the hydrogen content controller is adapted to adjust the hydrogen content of the reducing gas to a value higher than 30 vol.-%, preferably higher than 40 vol.-%, more preferably higher than 50 vol.-%.

27. An iron ore reduction and smelting apparatus according to any one of the preceding claims, further comprising a second hydrogen content controller for supplying reducing gas to the second injector, and adapted to adjust the hydrogen content of the reducing gas to a value above 25 vol.-%, preferably above 30 vol.-%, more preferably above 40 vol.-%.

28. An iron ore reduction and smelting apparatus according to any one of the preceding claims, further comprising an upstream regulating device adapted to control the mass flow rate of the reducing gas injected into the iron ore reduction and smelting apparatus at the tuyere layer to 800 kg / t HM, preferably below 775 kg / t HM, and more preferably below 750 kg / t HM at a pressure level above 2 barg, preferably above 4 barg and more preferably above 5 barg.

29. The iron ore reduction and smelting apparatus according to any one of the preceding claims, further comprising a regulating unit adapted to adjust the average degree of reduction of the iron oxide-containing material reaching the agglomeration zone to a value higher than 85% by controlling the amount and / or composition of the second reducing gas injected through the second injector at the shaft layer according to the amount and / or composition of the first reducing gas injected at the tuyere layer and / or the amount of oxygen injected through the oxygen injection port at the tuyere layer.

30. An iron ore reduction and smelting apparatus according to claims 10 to 14, wherein the plasma torch is a 3-phase AC plasma torch adapted to provide a (gas) velocity within the arc periphery of the plasma torch of 10m / s-120m / s, preferably 15m / s-80m / s, more preferably 18m / s-60m / s.

31. An iron ore reduction and smelting apparatus as claimed in claims 10 to 14 and 30, wherein the plasma torch is adapted to split incoming gas into two streams, in particular into a first stream flowing centrally through an arc generated by the plasma torch and a second stream flowing around the periphery of the arc.

32. A method for reducing and melting iron ore in a furnace, the method comprising the steps of: - Injecting a superheated reducing agent at a temperature of 1600°C-2600°C into the furnace at the tuyere layer; wherein the volume flow rate of the reducing gas injected at the tuyere layer is 500Nm 3 / t-1300Nm 3 / t molten iron, and the reducing gas contains 30%-100% (vol / vol) H2, with a pressure of 0.15kg / Nm 3 -0.85kg / Nm 3 density and a mass flow rate of 300kg / tHM to 800kg / tHM or / and wherein the coke rate of the method is lower than 200kg / t iron liquid; - thereby providing molten iron.

33. The method according to claim 32, wherein the first reducing gas is injected at the tuyere layer at a total mass flow rate of less than 800 kg / tHM, preferably less than 775 kg / tHM, and more preferably less than 750 kg / tHM.

34. The method according to any one of claims 32 or 33, wherein the density of the reducing gas at the tuyere layer is lower than 0.80 kg / Nm 3 , preferably less than 0.60kg / Nm 3 , and most preferably less than 0.30 kg / Nm 3 .

35. The method according to any one of claims 32 to 34, wherein the reducing gas at the tuyere layer has a hydrogen content higher than 30 vol.-%, preferably higher than 40 vol.-%, more preferably higher than 50 vol.-%.

36. A method according to any one of claims 32 to 35, wherein the reducing gas at the tuyere layer is injected at a temperature above 1800°C and more preferably above 2000°C.

37. A method according to any one of claims 32 to 36, wherein the reducing gas at the tuyere layer is heated by one or more electric heaters, preferably in branch ducts and / or tuyere, before being injected into the furnace.

38. The method of any one of claims 37, wherein the one or more electric heaters are one or more plasma torches.

39. The method according to any one of claims 38, wherein the reducing gas at the tuyere layer is heated by the one or more plasma torches arranged in the blowpipe of the branch duct, and the plasma torch is preferably an electrode-based plasma torch or an electrodeless plasma torch, such as selected from an induction ignition plasma torch, a microwave plasma torch, a radio frequency plasma torch or a combination thereof.

40. The method according to any one of claims 38 or 39, wherein the one or more plasma torches are DC plasma torches and / or AC plasma torches and / or 3-phase AC plasma torches.

41. A method according to any one of claims 38 to 40, wherein the plasma torch has a rated electrical power of 1 MW to 10 MW, preferably 2 MW to 6 MW, most preferably 4 MW to 5 MW.

42. The method according to any one of claims 32 to 41, further comprising injecting a reducing agent into the furnace at a shaft level at a temperature of 800°C - 1000°C.

43. The method according to any one of claims 32 to 42, wherein the first reducing gas injected at the tuyere layer and / or the reducing gas injected at the shaft layer comprises gas produced by a reforming process, in particular by reforming coke oven gas, natural gas, biogas and / or other hydrocarbon-containing gases with H2O, CO2 or a gas containing CO2 and / or H2O, and more preferably with steel mill waste gases such as smelter top gas, basic oxygen furnace gas and / or open bath furnace gas.

44. The method according to any one of claims 32 to 43, wherein the reducing gas at the tuyere layer and / or the reducing gas at the shaft layer has a molar ratio (H2+CO) / (H2O+CO2) greater than 6, preferably greater than 7 and more preferably greater than 8.

45. Method according to any of claims 42 to 44, wherein the reducing gas at the shaft layer has a hydrogen content higher than 25 vol.-%, preferably higher than 30 vol.-%, more preferably higher than 40 vol.-%.

46. ​​The method according to any one of claims 42 to 45, wherein the reducing gas is injected at the shaft layer at a temperature of 800 to 1200°C, more preferably at a temperature below 1100°C, and most preferably at a temperature below 1000°C.

47. A method as claimed in any one of claims 42 to 46, wherein the method comprises injecting reducing gas at the shaft level substantially along the circumference of the furnace so that gas rising from the agglomeration zone is centrally located within the furnace.

48. A method according to any one of claims 32 to 47, wherein the pressure level of the furnace at the tuyere layer is controlled to a value above 2 barg, preferably above 4 barg and more preferably above 5 barg.

49. The method according to any one of claims 32 to 48, wherein the reducing gas at the tuyere layer and the reducing gas at the furnace shaft layer have a nitrogen content lower than 35 vol.-%, preferably lower than 15 vol.-%, more preferably lower than 10 vol.-% and most preferably lower than 5 vol.-%; or the method according to any one of claims 32 to 48, the method further comprising cracking ammonia to provide the reducing gas injected at the tuyere layer or / and the furnace shaft layer.

50. The method for reducing iron ore in a blast furnace according to any one of claims 32 to 49, wherein the ratio between the volume flow rate of the reducing gas injected at the shaft layer and the volume flow rate of the reducing gas injected at the tuyere layer is 0:1 to 1:1, preferably 0.6 to 0.

65.

51. A method according to any one of claims 32 to 50, wherein the hydrogen in the reducing gas comprises hydrogen generated wholly / partially from renewable energy and / or from natural gas reforming with carbon capture, and / or wherein the reducing gas is heated and / or superheated using wholly / partial renewable energy and / or lean CO2 electricity such as from nuclear.

52. A method according to any one of claims 32 to 51, wherein recirculated top gas and / or other steelmaking gases are integrated into the mixed gas of the reducing gas generator after treatment in a gas cleaning unit or without treatment.

53. A method according to any one of claims 32 to 52, wherein the reducing gas generator comprises a gas separation technology such as PSA, VPSA, MEA for separating CO2, H2 or other compounds or mixtures thereof, and a reducing gas compression and heating device, wherein the device can be arranged in different configurations, preferably compression, separation and heating; or wherein the reducing gas generator comprises an H2 removal device that provides H2; or the reducing gas generator comprises an adsorbent-enhanced water-gas shift reactor, which converts H2O and CO into H2 and CO2, and then removes CO2 from the output.

54. A method according to any one of claims 32 to 53 comprising catalytic reforming and / or non-catalytic reforming.

55. The method according to any one of claims 32 to 54, wherein the reducing gas generator and / or the gas cleaning device are at least partly fed with cold hydrogen.

56. A method according to any one of claims 32 to 55, wherein the minimum coke layer thickness is at least 10 cm, such as 9 cm to 11 cm, or at least 15 cm, such as 14 cm to 15 cm.

57. The method according to any one of claims 32 to 56, further comprising the step of adjusting the average degree of reduction of the iron oxide-containing material reaching the agglomeration zone to a value higher than 85% by controlling the amount and / or composition of the reducing gas injected at the shaft layer according to the amount and / or composition of the reducing gas injected at the tuyere layer and / or the amount of oxygen injected at the tuyere layer.

58. A method according to any one of claims 32 to 57, further comprising injecting oxygen at the tuyere layer of the furnace, preferably at a temperature below 600°C, more preferably below 400°C.

59. A method according to any one of claims 32 to 58, further comprising the step of reducing channelling and flooding effects by controlling the top pressure of the smelting furnace in the range of 1 barg to 10 barg, more preferably in the range of 2 barg to 7 barg and most preferably between 3 barg and 5 barg.

60. The method according to any one of claims 32 to 59, further comprising the step of reducing the channeling effect of the gas from the agglomeration zone by controlling the injection conditions of the second reducing gas, such as the injection speed and / or velocity of the second reducing gas injected into the furnace body of the smelting furnace.

61. A method according to any one of claims 38 to 41, wherein the plasma torch is a 3-phase AC plasma torch, which is suitable for providing a (gas) velocity of 10m / s-120m / s, preferably 15m / s-80m / s, more preferably 18m / s-60m / s within the arc periphery of the plasma torch.

62. A method according to any one of claims 38 to 41 and 61, wherein the plasma torch is adapted to separate the incoming gas into two gas streams, specifically into a first gas stream flowing centrally through an arc generated by the plasma torch and a second gas stream flowing around the periphery of the arc.

Images