Iron ore reduction melting apparatus and method

Abstract

An iron ore reduction and melting apparatus comprising, from bottom to top, a hearth, a tuyere level, a shaft level, and a top level, the blast furnace as described above having at least one first gas injector on the tuyere level, and at least one first reducing gas generator connected to the at least one first gas injector, the apparatus providing a reducing gas containing 30 to 100% (vol / vol) hydrogen on the tuyere level and adapted to operate at a coke rate of less than 200 kg / t hot metal.

Description

[Technical Field]

[0001] The production of hot metal (HM) containing reduced iron generally requires a source of (oxidized) iron, i.e., iron ore, a reducing agent (coke, reducing gas) that allows the reduction of the oxidized form of iron to reduced iron, and an agent (coke, coal, oxygen, heater) that provides the necessary reaction temperature and energy for the reaction. Due to the use of coke in the reduction process, the reduction process generates a significant amount of CO2. [Background technology]

[0002] In general, it is desirable to reduce the CO2 output in the reduction process. Summary of the Invention [Problem to be solved by the invention]

[0003] It is therefore an object of the present invention to provide an apparatus and method capable of producing hot metal with reduced CO2 output. [Means for solving the problem]

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

[0005] An iron ore reduction and melting apparatus is disclosed, comprising: a furnace, for example a blast furnace, comprising, from bottom to top, a hearth, a tuyere level, a shaft level and a top level, said furnace comprising at least one first gas injector on the tuyere level; a reducing gas generator connected to the at least one gas injector, the apparatus being adapted to operate at a coke rate of less than 200 kg / t hot metal.

[0006] By providing the reducing agent outside the furnace, it is possible to reduce 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. The reducing agent, e.g., reducing gas, can include hydrogen (H2) and carbon monoxide (CO). In this way, it is possible to achieve coke rates of less than 200 kg / t hot metal. The hydrogen is generally provided as molecular hydrogen (H2).

[0007] The reducing agent may comprise 30-100% (vol / vol) hydrogen, and may optionally further comprise 10-70% (vol / vol) CO with less than 35%, 10%, or 5% of gaseous compounds that are not CO or H.

[0008] The first reductant generator may be a gas reformer providing H2, particularly a syngas reformer providing H2 and CO.

[0009] The blast furnace may also include at least one lock hopper for introducing material into the furnace from atmospheric pressure to furnace pressure.

[0010] At least one lock hopper ensures that the pressure within the blast furnace is maintained and therefore the reduction and melting process can be maintained.

[0011] The iron ore reduction and melting apparatus may further comprise at least one second gas injector on the shaft level.

[0012] The location of the at least one second gas injector can be (e.g., immediately) above the root of the agglomeration zone, which is the region of the agglomeration zone that directly contacts the furnace wall (i.e., above the root of the agglomeration zone).

[0013] Surprisingly, it has been found that the total coke requirement can be further reduced by also supplying reducing agent at the shaft level. In this way, the temperature levels required for ore melting 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 the high resistance agglomeration zone region.

[0014] The at least one first gas injector may include at least one electrically powered heater.

[0015] Electrically driven heaters have the advantage that they can be used to heat the reducing agent without locally consuming coal or coke. Because the heaters are electrically driven, the energy required for the heaters can be generated by CO2-lean energy. CO2-lean energy is energy that either produces small amounts of CO2 (photovoltaic, wind, hydroelectric, or nuclear energy) or does not produce more CO2 than is used to generate it (e.g., biogas from uncarbonized plant materials).

[0016] The path of the reducing agent generated in the reducing gas generator may include the reducing gas generator, the piping between the gas generator and the combustion tube, the combustion tube, the piping between the combustion tube and the gas injection point in the furnace (downleg, elbow, and blowpipe), and the tuyere. As used herein, a gas injector comprises a blowpipe and a tuyere.

[0017] The apparatus may be adapted to provide heated reducing agent in the piping between the gas generator and the combustion tube, in the piping between the combustion tube and the gas injector, and / or in the gas injector. Preferably, the apparatus may be adapted to provide heated reducing agent in the piping between the combustion tube and the gas injector or to the gas injector.

[0018] The apparatus, preferably the at least one first gas injector, may be adapted to heat the reducing agent to between 1600°C and 2600°C, between 1900°C and 2300°C, or between 2100°C and 2200°C, and provide the heated gas to the furnace at the tuyere level.

[0019] At these temperatures, the reduction of the ore by the reducing agent is efficient and can reduce the amount of coke and coal gasified in the tuyere.

[0020] The device is 500 to 1300 Nm 3 / t, 900~1300Nm 3 / t or 770~1000Nm 3 The reducing gas can be adapted to be injected into the blast furnace at tuyere level with a volumetric flow rate of 1 / t hot metal.

[0021] The device is 200 to 800 Nm 3 / t, 250-700Nm 3 / t or 250~600Nm 3 The reducing gas can be adapted to be injected into the blast furnace at shaft level with a volumetric flow rate of 1 / t hot metal.

[0022] At these volumetric flow rates, the reduction of the ore by the reducing agent is efficient and the amount of coke and coal can be further reduced.

[0023] The at least one first gas injector may be configured to heat the reducing agent and inject the reducing agent at a pressure of at least 2 and up to 10 bar absolute, 5-6 bar absolute, or 4-5 bar absolute.

[0024] At these pressure values, the reduction of the ore by the reducing agent is efficient and high productivity can be achieved.

[0025] Preferably, each of the above three conditions regarding temperature, volumetric flow rate, and pressure for at least the first gas injector can be combined.

[0026] The at least one electrically driven heater of the at least one first gas injector is adapted to operate at a power of 200-700 kWh / t, 250-600 kWh / t, or 300-550 kWh / t of hot metal.

[0027] The electrical power is adequate to heat the reducing agent to a desired temperature.

[0028] The electrically driven heater can be a plasma torch. A plasma torch is an electrically driven device that can heat a gas to a plasma physical state. A plasma torch can provide high gas temperatures that are not available with conventional heating systems. Furthermore, a plasma torch allows for flexible operation with respect to flow rate and temperature. In addition, it is a compact technology with a small volume footprint.

[0029] Plasma torches can be particularly (energy) efficient in providing the desired temperature, and are particularly efficient in heating gases from already high temperatures to even higher temperatures that are seldom efficiently possible with standard techniques. Thus, by configuring the apparatus to provide the plasma torch with gases heated to at least 900°C, or preferably 1100°C, the plasma torch can be used with reduced power requirements.

[0030] The plasma torch can be an electroded plasma torch or an electrodeless plasma torch.

[0031] In an electrodeless plasma torch, the plasma is inductively ignited and therefore no electrodes are required.

[0032] Electrodeless plasma torches can be microwave (MW) plasma and radio frequency (RF) plasma torches.

[0033] The plasma torch may be a plasma torch including an electrode, which may be a graphite electrode.

[0034] The plasma torch provided with the electrode can be a direct current plasma torch (DC plasma torch) or an alternating current plasma torch (AC plasma torch), in particular a three-phase AC plasma torch.

[0035] Plasma torches with electrodes are very energy efficient in providing the necessary temperature to the gases injected into the furnace.

[0036] DC plasma torches have the advantage of being fairly compact in size, i.e., they do not require a substantial amount of space.

[0037] Although AC plasma torches, particularly three-phase AC plasma torches, are not very compact in size, they offer many advantages.

[0038] AC plasma torches, especially three-phase AC plasma torches, provide a diffuse plasma. The plasma is confined to the ignition region, allowing for better control of the plasma's location. The AC current naturally cools the electrode, extending its lifespan. AC plasma torches can be water-cooled. Using a properly designed shell helps optimize heat transfer and efficiency losses. AC plasma torches do not require swirling gas like DC plasma torches, simplifying torch design. Because the plasma extension can be limited, refractory materials are only needed in a small area.

[0039] The electrode distance of a plasma torch, particularly a three-phase AC plasma torch, can be adjustable using a movable tilt electrode. The electrode distance can be 0-100 mm, 5-50 mm, or 40 mm. Adjustability allows for easier plasma ignition and greater plasma controllability and therefore stability.

[0040] AC plasma torches, especially three-phase AC plasma torches, can have three or many electrodes (e.g., 3, 6, 9, 12, 15, 18, 21, or more electrodes). More electrodes can improve plasma control and increase plasma torch power.

[0041] A DC plasma torch can have two or many electrodes (e.g., 2, 4, 6, 8, 12, 14, 16, 18, 20). A higher number of electrodes allows for better control of the plasma and increased plasma torch power.

[0042] The total power demand of the reactor as defined above is between 25 and 280 MW, and of course depends heavily on the production level of the reactor.

[0043] Plasma torches, in particular DC plasma torches and / or AC plasma and / or three-phase AC plasma torches with a power of 1 to 10 MW, preferably 2 to 8 MW, most preferably 3 to 5 MW, can be used in the furnace defined above.

[0044] In the furnace defined above, at least 10 gas injectors and up to 70 gas injectors, most preferably 18 to 40 gas injectors, are used.

[0045] In this way, the gas injected into the furnace is heated uniformly, providing efficient metal products.

[0046] The apparatus may further comprise a power supply that powers the at least one plasma torch.

[0047] Preferably, one power supply powers 1 to 5, 1 to 3, or 1 of the at least one plasma torch.

[0048] The use of multiple plasma torches powered by multiple power sources (each power source driving at least one plasma torch) of up to 30 MW or less than 10 MW has advantages over using a single power source with a total capacity equal to the sum of the capacities of all the lower-capacity power sources. In the former case, the flicker imposed on the power grid by plasma torch operation fluctuations is much less severe than in the latter case. To provide stable operation, it may be advantageous to use a power source in combination with each plasma torch with a power up to three times the power of the individual plasma torch.

[0049] Furthermore, using multiple power sources up to 30 MW or < 10 MW gives better control and flexibility: if a power source fluctuates or crashes, there is no disturbance propagation to the entire system and the other power sources can collectively provide the power input of the crashed source, so the furnace can continue to operate without serious problems.

[0050] In addition, one or more standby power sources can be installed online, ensuring steady-state operation at full power in the event of a primary power failure by switching to the standby power source. Repairs can be performed during the next scheduled maintenance shift, thereby preventing production loss.

[0051] However, a large number of power supplies leads to higher costs, higher power losses, and larger space requirements, so the optimum number of power supply units must be selected. In the furnaces defined above, at least 10 power units and up to 70 power units are used, most preferably 18-40 power units.

[0052] The plasma torch may be a three-phase AC plasma torch adapted to provide a (gas) velocity within the arc perimeter of the plasma torch of 10 to 120 m / s, preferably 15 to 80, more preferably 18 to 60 m / s. Within these ranges, optimal conditions for heating the gas are provided. If not all of the gas to be heated can pass through this perimeter, the remainder of the gas to be heated is supplied outside this perimeter.

[0053] Additionally, a plasma torch and method of using the plasma torch that reduces the heat load on the wall lining surrounding the plasma torch has been provided.

[0054] Thus, the plasma torch can be adapted to split the incoming gas into two flows, particularly a plasma torch configuration that provides a first flow that flows centrally through the arc generated by the plasma torch and a second flow that flows peripherally around the arc.

[0055] The central flow can flow through the plasma arc and be heated to a very high temperature. A second flow can be injected just downstream of the plasma arc and is oriented to protect the refractory-lined walls of the plasma burner chamber from the heat of the hot central flow, thereby reducing the thermal load on the wall lining.

[0056] The iron ore reduction melting apparatus may further comprise a plasma torch electrode replacement / repair device adapted to automatically replace / repair at least one used / corroded electrode of the plasma torch with a new electrode while the torch continues to operate.

[0057] In AC plasma torches, especially three-phase AC plasma torches, the electrodes generally have a rod shape. During operation, the side of the rod facing the plasma generation area deteriorates, shortening the electrode's length. The plasma torch is equipped with a feeding device that ensures that the inter-electrode distance on the side of the rod facing the plasma generation area is maintained by pushing the electrode toward the plasma generation area. After the electrode reaches a predetermined minimum length, a plasma torch electrode replacement / repair device can replace or repair the electrode.

[0058] Electrode modification is achieved by connecting the back side of the electrode (opposite the side of the electrode facing the area where plasma is generated) with a new electrode (e.g., by means of compatible protrusions and receiving openings on the used and new electrodes, which may be fitted with compatible threads). Attachment of the new electrode to the old electrode is achieved by an electrode gripper. Electrode modification devices have the advantage of being less likely to interfere with the operation of the device when modifying the electrode.

[0059] Alternatively or additionally, the iron ore reduction and melting apparatus may include an electrode paste column or paste feeder, which can be used to modify graphite electrodes with (e.g., carbon) paste. The intense heat and current during plasma operation gradually corrode and consume graphite electrodes. Such a method of modifying electrodes with paste can at least partially or completely reverse the erosion or consumption. Carbon paste, typically a mixture of graphite and a binder, is applied to the consumed or worn portions of the electrodes.

[0060] This paste replenishes the carbon content, extends the life of the electrode, and helps maintain efficient electrical conductivity and heat transfer during plasma operation.

[0061] The electrode paste column or paste feeder is adapted to introduce carbon paste into the electrode column without interrupting the plasma process.

[0062] The process involves delivering an electrode paste column to the worn or corroded portion of a graphite electrode. The column contains a carbon paste mixture, which is then gradually forced into the electrode column. As the paste is introduced, it fills the voids left by the consumed electrode material and restores the carbon content.

[0063] This method allows for controlled and precise addition of carbon paste, ensuring that electrode performance and efficiency are maintained throughout plasma operation, which helps extend the operating life of the electrode and contributes to the overall effectiveness of plasma operation.

[0064] In DC plasma torches, the electrode may have a tubular shape. During operation, the side of the tube facing the plasma generation area deteriorates, shortening the electrode's thickness. A plasma torch electrode replacement device removes a torn electrode from the plasma torch and places a new electrode into the plasma torch. Replacement of the used electrode with a new one is achieved by an additional electrode gripper.

[0065] The plasma torch electrode replacement / repair device is controlled by a control unit (e.g., a computer device) that determines the condition of the electrode in use (e.g., by a suitable camera or the electrical characteristics of the plasma torch). When said control unit determines that a minimum length / thickness of the electrode has been reached, the control unit commands the replacement / repair device to replace or repair the used electrode.

[0066] The plasma torch electrode replacement / repair device can include a magazine for unused (new) electrodes. The plasma torch electrode replacement / repair device can further include a magazine for used electrodes. In this way, the plasma torch electrode replacement / repair device can operate without manual interaction for a predetermined period of time.

[0067] The blast furnace may include a plurality of first and / or second gas injectors.

[0068] 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.

[0069] Additionally, the blast furnace may be equipped with at least a 10 second second gas injector and a maximum of a 70 second second gas injector, most preferably an 18 to 40 second second gas injector.

[0070] The plurality of first and / or second gas injectors may be arranged substantially equally spaced and / or in a circular pattern.

[0071] The outlets of the respective injectors can be evenly spaced apart from each other at a distance of 0.5 to 2.5 m, preferably 1.0 to 1.5 m.

[0072] The iron ore reduction and melting apparatus may further comprise at least one sensor adapted to analyze the composition of the gas at the top level, which may be located within the furnace in the top level or connected to a pipe that collects the gas from the top level of the furnace.

[0073] The sensor may be of electrochemical, catalytic bead (pellistar), photoionization, infrared spot, infrared imaging, semiconductor, or ultrasonic type. Semiconductor type sensors may be metal oxide semiconductor sensors. The sensor may be included in a gas chromatograph.

[0074] 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.

[0075] The iron ore reduction and melting apparatus may further comprise a gas injector adjusting device configured to adapt the composition of the gas and / or the volume of the gas injected by the first and / or second gas injectors based on the determined gas composition and / or temperature at the top level.

[0076] The gas injector regulator may also adapt the power supply to the at least one electric heater based on the determined gas composition at the top level and / or the temperature at the top level.

[0077] The gas injector adjustment device may also be configured to adapt the composition of the gas and / or the volume of the gas and / or the temperature of the injected gas injected by the first and / or second gas injectors based on the composition and / or temperature of the molten iron output by the device and the molten iron production rate.To determine the composition of the molten iron output by the device and the molten iron production rate, the device comprises further sensors arranged at the molten iron outlet of the furnace configured to determine the composition of the molten iron and to determine the volume of the molten iron.

[0078] The above-defined device has the advantage that it makes it possible to reduce oxygen consumption during hot metal production and therefore CO2 emissions.

[0079] Therefore, the iron ore reduction melting apparatus may further include an oxygen supply device adapted to inject a gas containing a smaller amount of oxygen than in a conventional smelting reduction apparatus. 3 / t hot metal less than 80Nm 3 / t hot metal less than 40Nm 3 / t hot metal or less than 30Nm 3 For example, the oxygen supply device may be adapted to inject an oxygen-containing gas at a rate of 1 to 120 Nm / t hot metal. 3 / t hot metal, 1~80Nm 3 / t hot metal, 1~40Nm 3 / t hot metal, 1~30Nm 3 / t or 0Nm 3 It may be adapted to inject at / t.

[0080] The oxygen-containing gas may contain at least 75% (vol / vol) oxygen, or at least 95% (vol / vol) oxygen, for example, 75% to 99% (vol / vol) oxygen, or 95% to 99% (vol / vol) oxygen.

[0081] Optionally, the iron ore reduction and melting apparatus comprises a device for supplying oxygen to the blast furnace, the device for supplying oxygen being preferably used only in a transient phase (e.g., restarting after a maintenance shutdown).

[0082] The iron ore reduction melting apparatus may further comprise a gas scrubber adapted to recycle the blast furnace top gas. The gas scrubber may be connected to the top level of the blast furnace by piping. The gas scrubber may comprise a pressure regulator for controlling the pressure at the top of the furnace in the range of 1 to 10 barg, more preferably 1.5 to 6 barg, most preferably 2 to 4 barg. The gas scrubber is adapted to remove dust, HO, and optionally sulfur, chlorine and / or other undesirable compounds.

[0083] The reducing gas generator can be a gas reformer or a CO2 remover. The use of a gas reformer is preferred. The reducing gas generator can also be an H2 remover that provides H2. The removed H2 can be used as reducing gas in the process, and the remaining portion can be used in the burner. An adsorbent-enhanced water-gas shift reactor that converts CO2 to H2 can also be part of the reducing gas generator. For example, it can be combined with an H2 remover to further increase the H2 recovery rate.

[0084] The gas output by the reducing gas generator may contain a reducing agent to oxidizing agent ratio (CO+H2) / (CO2+H2O) at a % (vol / vol) greater than 7, 8, or 9. The ((CO+H2) / (CO2+H2O)) ratio may be 6-80, 7-30, or 8-12.

[0085] The amount of reducing gas, particularly hydrogen, that must be supplied by the first reducing gas generator can be reduced, since those portions of the gas from the top level suitable for supplying and / or generating reducing gas are at least partially recycled. Thus, the amount of reducing gas or components that provide reducing gas required can be reduced. Part of the top gas can also be used for burners and / or gas reforming.

[0086] The iron ore reduction melter may be adapted to provide hydrogen-containing (possibly purified / treated) top gas to the gas coming from the gas generator which supplies the gas to the second injector (e.g., when its temperature is higher, particularly in non-catalytic reforming for cooling of the reducing gas going to the shaft injector).

[0087] Connections between the various devices of the apparatus may be provided by suitable piping.

[0088] The first reducing gas generator may be a catalytic or non-catalytic reformer, a regenerative reformer without a catalyst configured to provide reducing gas at temperatures above 1100°C.

[0089] The use of such a reformer providing a reducing gas at a temperature of 1100°C or higher and providing hydrogen in the reducing gas has the advantage that the reducing gas is already preheated to a relatively high temperature before being heated in the first gas injector or / and the second gas injector. In addition, the ((CO+H2) / (CO2+H2O)) ratio is improved compared to catalytic processes operating at lower temperature levels.

[0090] A method for reducing and melting iron ore in a blast furnace is disclosed, comprising the steps of: Injecting superheated reducing gas at a temperature of 1600-2600°C into the furnace at the tuyere level (the volumetric flow rate of the reducing gas injected at the tuyere level is 500-1300 Nm 3 / t hot metal, the reducing gas comprising 30-100% (vol / vol) H, and the coke rate of the process being less than 200 kg / t hot metal; and - thereby providing hot metal.

[0091] Surprisingly, it has been found that by using the above-defined amount of hydrogen in combination with the above-defined volumetric flow rate of reducing gas injected at the tuyere level, the coke rate is substantially reduced.

[0092] The method may be carried out using the apparatus defined above.

[0093] The method may further include injecting a reducing gas into the furnace at shaft level at a temperature of 800°C to 1000°C.

[0094] Surprisingly, it has been found that additional injection of a reducing gas as defined above reduces the coke rate even further.

[0095] The method may include injecting reducing gas at shaft level substantially along the periphery of the blast furnace such that gas rising from the agglomeration zone converges centrally within the blast furnace.

[0096] Surprisingly, it has been found that by injecting a reducing gas as defined above, the coke rate is reduced.

[0097] The ratio of the volumetric flow rate of the reducing gas injected at the shaft level to the volumetric flow rate of the reducing gas injected at the tuyere level is 0:1 to 1:1.

[0098] In other words, a ratio of 0:1 covers the case where no reducing gas is injected at shaft level and reducing gas is injected only at tuyere level.

[0099] When additional reducing gas is injected at the shaft level, the coke rate decreases until it is optimal when the amount of gas injected at the tuyere level is increased. Thus, the ratio of the volumetric flow rate of reducing gas injected at the shaft level to the volumetric flow rate of reducing gas injected at the tuyere level 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.

[0100] The method may include not using supplemental fuel injection (eg, coal) in performing the method.

[0101] In the above defined method, the hydrogen in the reducing gas may comprise hydrogen produced wholly / partially from renewable energy and / or from natural gas reforming with or without carbon capture, and / or the reducing gas is heated and / or superheated wholly / partly using renewable energy and / or using lean CO2 electricity such as from nuclear. [Brief explanation of the drawings]

[0102] [Figure 1] 1 shows the disclosed iron ore reduction apparatus comprising a blast furnace and a first reducing gas generator. [Figure 2] 1 shows the zones within a blast furnace and the injection sites for various gases that may be injected into the blast furnace. [Figure 3] Shows the zones inside the blast furnace. DETAILED DESCRIPTION OF THE INVENTION

[0103] 1 shows a schematic representation of an iron ore and smelting apparatus 1 disclosed in the present application. Each element of the apparatus, in particular the apparatus, generators, etc., is also disclosed separately. Additionally, the disclosed apparatus 1 can include any number of the illustrated apparatuses, generators, etc.

[0104] The solid arrows represent the direction of gas flow within the piping and the device 1. The dotted arrows represent wireless or wired communication lines within the device 1, particularly to and from the control device.

[0105] The apparatus 1 comprises a blast furnace 2. The blast furnace 2 comprises, from bottom to top, a hearth 10, a region with tuyere levels 3, a shaft region with shaft levels 4, and a top level 5.

[0106] At tuyere level 3, a first gas injector 6 is installed. The first gas injector 6 is used to inject reducing gas into the blast furnace 2. The tuyere level 3 (or area) can also be used to inject oxygen into the blast furnace 2 via an oxygen supply 11.

[0107] The first gas injector may be equipped with an electrically driven heater, preferably a plasma torch (not shown).

[0108] The lock hopper 8 is used to feed materials (e.g., coke, ore, and optionally flux) into the interior of the blast furnace 2 while ensuring that pressure conditions are maintained within the blast furnace 2. At shaft level 4, the blast furnace may also include at least one second gas injector 9 that can be used to inject reducing gas into the shaft level / region.

[0109] Both the first and second injectors 6 and 9 can receive reducing gas from a reducing gas generator 7. The reducing gas generator 7 may be a syngas generator. The reducing gas supplied by the reducing gas generator 7 can contain 30 to 100% (vol / vol) hydrogen. The reducing gas can be generated 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 from local or remote hydrogen storage, such as green or blue hydrogen. Hydrogen can be obtained from an electrolytic cell. Alternatively, the reducing gas generator can generate reducing gas by separating H2O and / or CO2 from H2- and / or CO2-rich gases, such as top gas and BOF gas. Common or separate reducing gas generators can be used for the tuyere and shaft levels. The separate reducing gas generators can be the same type or different types.

[0110] The gas present at the top level can be continuously or intermittently withdrawn from the top level 5 of the furnace 2. The gas recovered from the top level can be recycled using a gas scrubber 12 and, optionally, a gas conditioning unit (not shown) that removes some components such as water, chlorine, sulfur components such as COS, or / and heavy metals. The gas treated by the gas scrubber 12 (and optionally the gas conditioning unit) can be fed to the reduction gas generator 7 or can be fed to a path (after the reduction gas generator 7) that leads to an injector at the shaft level 4. At this location, feeding purified BOF gas is also highly advantageous due to its high degree of reduction.

[0111] The gas can be analyzed by a sensor 13 in contact with the recovered gas. While the sensor 13 is shown in FIG. 1 as being at the end of the piping connected to the furnace 2, the sensor 13 could also be provided in the furnace or any other piping accessing the recovered gas from the top level 5. Because the water content in the gas can be a relevant factor for stoichiometric control of the mixed gas (hydrocarbon source and furnace gas) going to the gas reformer, additional sensors 17, at least humidity and / or temperature sensors, can be provided after gas scrubbing and water removal. The sensors 13 and / or 17 provide data to the gas injector regulator 14. The gas injector regulator 14 comprises an electrical circuit with a memory capable of processing the data provided by the sensor 13 and sending signals to the first and / or second gas injectors 6, 12, the reduction gas generator 7, and / or the gas scrubber 12. For example, the gas output, composition, and temperature from the reduction gas generator or the gas scrubber 12 can be adapted accordingly. For example, the temperature of the gas provided by the gas injector may be adapted by reducing the power supplied to the plasma torch. The gas injector regulator 14 can also process inputs from other sensors, such as sensors that inspect the hot metal quality or the hot metal production rate. Based on the data provided by the sensors, the gas injector regulator 14 can modify the composition of the gas produced by the gas generator 7 or the conditions (e.g., temperature, pressure, volumetric flow rate) applied to the first and / or second gas injectors 6, 9.

[0112] The gas pressure can be measured by a sensor 16 in contact with the recovered gas. Although the sensor 16 is shown in Figure 1 as being at the end of the piping connected to the furnace 2, the sensor 16 can also be located in the furnace or any other piping that accesses the recovered gas from the top level 5. The sensor 16 provides data to a pressure regulator included in the gas scrubber 12.

[0113] FIG. 2 shows the zones within a blast furnace and the injection sites for various gases that can be injected into the furnace.

[0114] The material in the operating furnace 2 includes, from top to bottom, a shaft region 22 and agglomeration zone 23. The shaft region 22 and agglomeration zone 23 contain alternating layers of material including ore 29 and coke 21. Following the agglomeration zone 23 is a drip zone 24, which includes a raceway 25 near the tuyere.

[0115] At the tuyere level 28, reducing gas, oxygen, and / or hot air can be injected into the furnace 2. At the shaft level 27, reducing gas can optionally be injected into the furnace 2. The shaft level 27 can also be considered to be the level at which the stack angle of the web part 15 changes from 0° to a value different from 0°. Alternatively, the shaft level is the level starting from the root of the cohesion zone 23.

[0116] Reference Examples and Examples of the Present Disclosure To better illustrate this disclosure, several cases have been investigated in detail. The details of the cases are shown in Table 1.

[0117] Cases 1 and 2 Cases 1 and 2 are reference units operating today with crude coke rates of 255 kg / tHM and 205 kg / tHM, respectively.

[0118] Cases 3 and 4 are the reference unit with hot hydrogen injection into the tuyere with and without hot hydrogen injection into the shaft, respectively.

[0119] Cases 5 and 6 are new furnaces (equipment with furnace of the present disclosure) with coke rates of 180 kg / tHM and approximately 100 kg / tHM using superheated syngas injection at the tuyere level.

[0120] Cases 7 and 8 relate to new furnaces (apparatus including further furnaces of the present disclosure) with coke rates of 180 kg / tHM and 100 kg / tHM, using superheated syngas injection at the tuyere level and additional hot syngas injection into the shaft.

[0121] Case 1 represents a typical well-operated blast furnace with high pulverized coal injection, such as some found around the world, especially in Europe. Pulverized coal injection (PCI) makes it possible to reduce the lump or crude coke rate to a value of about 250 kg / tHM.

[0122] As can be seen, this furnace produces approximately 235 Nm3 per tonne of hot metal produced. 3 Part of this oxygen comes with the heated air and part of it comes from oxygen enrichment with pure oxygen coming from an air separation plant.

[0123] This oxygen enrichment is necessary because blast furnaces require a certain flame temperature to operate correctly. In fact, the flame temperature ensures that the reduced ore can be melted and that the injected coal can be burned in the raceway. At high PCI injection, the required flame temperature is about 2200°C.

[0124] Case 2 represents a typical blast furnace that reaches exceptionally high PCI injection. This operation has already been carried out over a long production period of several months. However, this operation is very difficult and requires high operating skills and very good raw materials, especially high-quality, expensive coke.

[0125] Comparing the injection conditions at the tuyere, it can be seen that although oxygen enrichment needs to be further increased, the conditions at the tuyere, hot blast temperature and gas volumetric flow rate have not changed significantly overall.

[0126] Both of these operations are completely coal based in energy and reductant input and are therefore naturally undesirable if one wants to reduce CO2 emissions from hot metal production.

[0127] Cases 3 and 4 In these examples, blast furnace operation was analyzed using high hydrogen injection rates to reduce some of the energy and reductant input from coal and use CO2-free hydrogen instead.

[0128] It is known that hydrogen cannot be injected in large quantities when injected cold at the tuyere together with oxygen-enriched hot blast. The typical maximum amount of hydrogen utilization is limited to less than 30 kg / tHM.

[0129] Therefore, the addition of hydrogen requires modification: it needs to be injected hot only at the tuyere level or at both the tuyere and shaft levels.

[0130] The injection temperatures were assumed to be 950°C at the shaft level and 1200°C at the tuyere level.

[0131] These are temperature levels that can typically be reached when using conventional heat exchangers and regenerative heaters.

[0132] At the tuyere level, cold oxygen must be added to burn the coke to reach the flame temperature required to melt the ore. It is known from furnaces that use natural gas injection rather than PCI injection that in this case the flame temperature can be reduced to a minimum of about 1800-1850 °C, providing sufficient flow rate at all times to provide enough energy to melt the reduced ore and to provide the energy for heating and reducing the ore in the shaft of the blast furnace.

[0133] As can be seen, oxygen injection at the tuyere was increased from about 240 to 150 and 180 Nm 3 / tHM. Therefore, less carbon can be burned in the tuyeres. However, since there is no carbon available from PCI injection, the coke that needs to be burned in the tuyeres is high, as in Cases 1 and 2, resulting in an increase in the coke rate.

[0134] Incidentally, carbon is the only element in typical fuels that can combust with oxygen at tuyere conditions to form CO and thus heat the inlet gas. CO2 and HO cannot be formed under the reducing conditions found at the tuyere. If CO2 and / or HO are present in the inlet gas, they have the adverse effect of causing coke to be consumed by endothermic gasification, resulting in a reduction in flame temperature.

[0135] This conflict between the required CO2 emission reduction and the additional coal / coke requirement when using hydrogen in the blast furnace cannot be overcome by conventional methods.

[0136] Furthermore, pure hydrogen injection requires large amounts of hydrogen in both the cases with and without shaft injection, 1070 and 1280 Nm3 / t of hot metal with and without shaft injection, respectively. 3 This far exceeds the hydrogen requirements of other production routes, such as the direct reduction process, which requires approximately 660 Nm3 / tHM of hydrogen. Furthermore, the coking rates required in these cases are so high that they are not of interest.

[0137] To overcome this problem, injection of synthesis gas into the blast furnace at superheated temperatures, with or without pure hydrogen addition, has been proposed.

[0138] Heating can be achieved, for example, by a plasma torch.

[0139] Cases 5 and 6: In these cases, superheating the gas injected at tuyere level has the advantage that coke does not need to be burned with oxygen to obtain the temperature levels at the tuyere required to melt the reduced ore.

[0140] Cases 7 and 8: These cases have additional syngas injection into the shaft compared to cases 5 and 6.

[0141] Operating the furnace with partial gas injection into the furnace shaft can provide the temperature levels required for melting with lower electrical energy requirements from the plasma torch. Additionally, shaft injection requires less gas to pass through the high resistance coagulation zone region.

[0142] As can be seen, in the two examples it is possible to reach very low coke rates of about 180 and 100 kg / thm, respectively.

[0143] 440Nm 3 In the case of 100 kg / thm coke with / thm, the hydrogen addition is also very low.

[0144] This hydrogen addition can be reduced by recycling the blast furnace top gases back into the blast furnace via a reducing gas generator.

[0145] For this purpose, the dust, HO, and CO2 contents must be reduced. Dust can be reduced in a dry or wet gas scrubbing system. In the case of a wet gas scrubbing system, some of the HO is also removed. If necessary, the HO can be easily further reduced by cooling and condensation (e.g., by a condenser, quench, etc.). Other removal systems can be used to treat undesirable components such as oxygen, chlorine, sulfur components such as COS, heavy metals, etc. CO2 removal can be achieved using any CO2 removal technology, such as MEA, pressure swing adsorption (PSA), vacuum pressure swing adsorption (VPSA), or CO2 can be reformed with hydrocarbons to form CO and hydrogen.

[0146] In our example, natural gas reforming is applied.

[0147] Reforming can be carried out catalytically at temperatures of about 950°C or without a catalyst in a regenerative reformer type at high temperatures >1100°C.

[0148] The latter type is very well suited to preparing gas at tuyere level, since particularly at that level very high temperatures are desirable.

[0149] Also, when the gas is reformed at high temperatures, it is possible to reach a very high degree of reduction of the gas (CO + H / (CO + H O) > 7, preferably > 8, more preferably > 9. A high degree of reduction is very important to achieve low coke velocities, because if all the CO and H O in the gas were injected into the tuyeres, it would consume the coke in the raceway and reduce the flame temperature.

[0150] The CO2 and H2O injected at shaft level reduce the degree of direct reduction of the ore going to the agglomeration zone, and therefore require coke for its complete reduction in the direct reduction zone.

[0151] [Table 1]

[0152] Since we wish to discuss the influence of some gases produced or injected into the furnace on important issues, it is better to introduce them and identify their location as shown in Figure 2 to avoid misunderstandings.

[0153] The volumetric flow rates of these gases are summarized in the table below:

[0154] [Table 2]

[0155] Coke consumption Coke in the unit is consumed by solution loss reactions in the shaft, carburization, direct reduction in the liquid state (above the dripping zone), and coke gasification / combustion in the tuyeres. Additionally, small amounts of coke fines are picked up by the top gases.

[0156] In the table below, the amount of coke consumed by the mentioned means is given in all cases.

[0157] [Table 3]

[0158] It can be seen that coke consumption by direct reduction in the liquid state is significantly lower in the new furnace. This is because the iron load is highly reduced in the shaft due to the very high reductant-to-oxidant ratio in the furnace. Therefore, less FeO remains to be reduced to Fe° by direct reduction and loss-of-solution reactions. In cases 5-8, coke consumption by direct reduction is less than 20 kg / tHM, compared to over 70 kg / tHM in the conventional furnace.

[0159] It can also be seen that the reducing gas injected into the shaft limits the coke consumption by solution loss in cases 7 and 8. Therefore, it is believed that the injection of reducing gas does not result in an increase in the coke quality requirements for the new furnace case.

[0160] Furthermore, the superheated reducing gas provides a significant amount of heat energy into the unit, reducing the amount of coke required to be burned in the tuyere.

[0161] What has been described here shows that coke rates can be reduced to very low levels using superheated reducing gas injected into the tuyeres and, optionally, hot reducing gas at shaft level.

[0162] Gas flow Blast furnaces are known to have already been successfully operated at crude coke rates of 210 kg / tHM using high pulverized coal injection rates fed with high oxygen-enriched hot blast (hot blast).

[0163] The oxygen consumes the injected coal and coke, thus providing the energy to heat the tuyere gases to the high temperature levels in the raceways required to melt the reduced ore.

[0164] To reduce CO2 emissions coming from the blast furnace, it is desirable to eliminate injected coal and reduce the coke rate as much as possible.

[0165] For this reason, the total amount of oxygen injected into the tuyere should be kept at a low level, preferably 120 Nm 3 It is necessary to reduce the HT to below / tHM.

[0166] To provide energy at high temperature levels to melt the reduced ore, the tuyere gas volumetric flow rate can be slightly reduced by about 20% compared to conventional smelting reduction units if typical raceway temperatures of 1800-2600°C are maintained.

[0167] Since reducing gas is no longer produced, or at least only to a small extent, inside the raceways of a blast furnace, it is necessary to produce the reducing gas externally and feed it into the furnace.

[0168] Table 4 shows the total mass flow rate injected into the furnace for all cases considered. It is clear 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 shown in Table 5.

[0169] It is argued that this can only be reached if the mass flow rate of gas injected at the tuyere is kept below 800 kg / tHM in order not to exceed acceptable hydrodynamic conditions in the agglomeration zone when having very low coke velocities of less than 200 kg / tHM (see Table 4).

[0170] To do so, the hydrogen content of the gas injected at the tuyere level must be higher than 30%. It should be noted that although the total mass flow rate in the case of pure hydrogen (100%) is lower than in our case, the coke rate is higher at 274 kg / tHM and 324 kg / tHM.

[0171] [Table 4]

[0172] [Table 5]

[0173] To estimate the impact of such lower coke velocity on the cohesion zone in terms of pressure drop, parameters of the gas (bosh gas) entering the cohesion zone (CZ) are needed. Bosh gas is the result of the injection gas into the tuyere, coke combustion (if O2 is injected), coke gasification (if H2O and CO2 are present), and CO produced by the final reduction reaction with the liquid state (FeO(l) + C(s) → Fe(l) + CO) and non-oxidized iron (SiO2, MnO, PO3, etc.).

[0174] The inventors have surprisingly found that it is possible to reduce the gas volume passing through the coagulation zone by injecting some of the gas into the furnace shaft. This can be seen in Cases 7 and 8, which involve shaft injection, where the volume of gas moving through the CZ is significantly lower in the new system.

[0175] [Table 6]

[0176] To estimate the pressure drop across the CZ, we assumed that the ore layer was impermeable. Furthermore, it is assumed that a portion of the molten slag penetrates the coke layer in the CZ and blocks a portion of the coke layer. This coke-ore interface layer is also considered the impermeable thickness. Therefore, all the ascending gas passes only through the CZ coke layer, as shown in Figure 3.

[0177] The coke layer thickness, excluding the interface layer, is 15 cm in the BF examples (Cases 1 and 2). The interface layer thickness is assumed to be 4 cm. Since the coke layer thickness is an important factor for stable furnace operation, this value is kept constant for all cases. Advantageously, the minimum coke layer thickness is at least 10 cm (9-11 cm) or at least 15 cm (14-16 cm). The material feeder can be adjusted to provide the required thickness.

[0178] As the coke velocity decreases, the total gas passage area in the coalescence zone becomes smaller, and to maintain an acceptable pressure drop in the coalescence zone, the volumetric flow rate and density of the bosh gas should be reduced.

[0179] As can be seen from Table 6, the pressure drop in the CZ for Case 2 is much higher than Case 1 due to the lower coke velocity.

[0180] The new equipment for a coke rate of 180 kg / tHM can operate better because the bosch gas can move much more smoothly through the CZ. Nevertheless, reducing the coke rate to the final value of 100 kg / tHM without shaft injection is difficult because the pressure drop in the CZ is very high. This means that Case 6 has a higher risk of flooding and load hanging.

[0181] This problem can be overcome by increasing the pressure of the injected gas. Higher tuyere gas pressure increases the density and reduces the velocity of the gas entering the furnace. Since pressure drop is related to the square of the velocity, the effect of velocity on pressure drop is much greater than density.

[0182]

number

[0183] However, this problem can be alleviated by shaft injection, which results in a lower volumetric flow rate of gas injected into the tuyere, resulting in a lower pressure drop. It can be clearly seen that the pressure drop in Case 8 (new furnace) is even lower than in Case 2.

[0184] Furthermore, the pressure drop in the CZ and trickle zone is lower in the new system, allowing for increased production rates. This is achieved by the effect of hydrogen on the density of the gas, providing the desired pressure drop. To achieve the pressure drop level of the conventional system (Case 2), the production rate could be increased by 15%. Thus, the benefit of shaft injection is again demonstrated in Case 8.

[0185] The table below shows the pressure drop for Case 8 with lower and higher production rates.

[0186] [Table 7]

[0187] plasma torch The plasma torches disclosed in this application can be DC or AC plasma torches.

[0188] An AC three-phase plasma torch can exhibit the following characteristics:

[0189] The core of the plasma can reach temperatures of approximately 15,000K or higher.

[0190] Most preferably, graphite electrodes having an outer diameter of 50 to 200 mm, 100 to 150 mm, or 130 mm can be used.

[0191] AC voltages of 100V to 1500V can be applied. Of note, such voltages can also be applied to DC torches. Higher voltages, such as kV, can also be applied to reach higher power outputs, e.g., 2 to 8 MW.

[0192] The electrode distance of the plasma torch is adjustable (0-100mm or can reach a gap of 40mm, a higher gap of 100mm is possible). The adjustability allows for easier plasma ignition and higher plasma stability.

[0193] Plasma control can be based on visual observation, where pictures of the plasma continuously captured by a camera are benchmarked against steady-state plasma pictures using associated software. Respective changes (i.e., electrode distance, voltage amplitude, etc.) are then imposed to maintain the plasma in a stable state.

[0194] If spare electrodes are continuously loaded into the electrode magazine, the plasma torch can operate for weeks or months.

[0195] Six arc plasmas are generated in each cycle, one by one, between three electrodes that alternately play the role of anode and cathode.

[0196] The alternating ignition points of the plasma make it more diffusive, resulting in higher gas volume treatment than DC plasma torches. Perhaps 30% of the gas can be treated in one pass.

[0197] Electrode life can be increased, especially for graphite electrodes, if the reducing gas has low concentrations of oxygenated species, i.e., HO and CO. The reducing gas may contain a reductant to oxidant ratio (CO+H / (CO+H)O) of greater than 7, 8, or 9% (vol / vol). The ((CO+H) / (CO+H)O) ratio can be 6-80, 7-30, or 8-12.

[0198] Therefore, a minimum degree of reduction of the gas should be maintained and / or the concentration of H2O+CO2 should be limited to values ​​below 35% by volume, below 10% by volume, preferably below 5% by volume.

[0199] Example The following examples are also provided: Example 1. An iron ore reduction and melting apparatus, a furnace comprising, from bottom to top, a hearth, a tuyere level, a shaft level, and a top level, the furnace comprising at least one first gas injector on the tuyere level; at least one reducing gas generator connected to at least one first injector, the first injector providing a reducing gas containing 30-100% (vol / vol) hydrogen and having a density at tuyere level of 0.15-0.85 kg / Nm3 and a mass flow rate of 300-800 kg / tHM or / and a volume flow rate of 500-1300 Nm3 / tHM, and adapted to operate at a coke rate of less than 200 kg / t hot metal.

[0200] Example 2. The iron ore reduction and smelting apparatus of Example 1, further comprising at least one second gas injector on the shaft level.

[0201] Example 3. The iron ore reduction and melting apparatus according to Example 1 or 2, wherein the at least one first gas injector comprises at least one electrically driven heater.

[0202] Example 4. An iron ore reduction and melting apparatus according to any one of the preceding examples, wherein the at least one first gas injector is adapted to heat the reducing gas to 1600°C to 2600°C, preferably 2100 to 2200°C, and to inject the reducing gas into the blast furnace at a volumetric flow rate of 500 to 1300 Nm3 / t hot metal, and to inject the reducing gas at a pressure of at least 2 to a maximum of 10 bar absolute, preferably 4 to 5 bar absolute, and / or wherein at least one electrically driven heater of the at least one first gas injector is adapted to operate with a power of 200 to 600 kWh / t hot metal.

[0203] Example 5. The iron ore reduction and melting apparatus according to Example 3, wherein the heater is a plasma torch, and is a plasma torch with an electrode or an electrodeless plasma torch.

[0204] Example 6. The iron ore reduction and melting apparatus according to Example 5, wherein the plasma torch is a plasma torch equipped with an electrode, and the iron ore reduction and melting apparatus further comprises a plasma torch electrode replacement / repair device adapted to automatically replace at least one used or corroded electrode of the plasma torch with an unused electrode / automatically repair the used electrode with at least one new electrode, and the plasma torch electrode replacement / repair device comprises a magazine for unused electrodes.

[0205] Example 7. The iron ore reduction and melting apparatus according to Example 5, wherein the plasma torch is an AC plasma torch, more preferably a three-phase AC plasma torch having three or more than three electrodes, or the plasma torch is a DC plasma torch having two or more than two electrodes.

[0206] Example 8. An iron ore reduction and melting apparatus according to any one of the preceding examples, wherein the blast furnace comprises a plurality of first and / or second gas injectors, the plurality of first and / or second gas injectors being arranged substantially equally spaced and / or in a circle, and optionally the outlets of each injector being independent of each other and evenly distributed at a distance of 0.5 to 2.5 m, preferably 1.0 to 1.5 m, from each other.

[0207] Example 9. An iron ore reduction and melting apparatus according to any one of the previous examples, further comprising a sensor adapted to analyze the composition of the gas at the top level in terms of CO, CO2, H2 concentration in the gas, and optionally also adapted to analyze the composition of the gas in terms of H2O, N2 or CH4 concentration in the gas, and / or further comprising a temperature sensor adapted to measure the temperature of the gas at the top level, and / or further comprising a sensor for humidity measurement after gas cleaning and pre-treatment.

[0208] Example 10. The iron ore reduction and melting apparatus of Example 9, further comprising a gas injector adjustment device configured to adapt the composition of the gas and / or the volume of the gas injected by the first and / or second gas injectors based on the gas composition determined at the top level, and optionally configured to adapt the gas composition and / or the gas volume based on the composition of the molten iron output by the apparatus and the molten iron production rate.

[0209] Example 11. The iron ore reduction and melting apparatus of any one of the previous examples, further comprising an oxygen supply device adapted to inject oxygen into the blast furnace at less than 120 Nm3 / t hot metal, less than 80 Nm3 / t hot metal, less than 40 Nm3 / t hot metal, less than 30 Nm3 / t hot metal, and 0 Nm3 / t hot metal.

[0210] Example 12. An iron ore reduction and melting apparatus according to any one of the preceding examples, further comprising a gas scrubbing device, optionally adapted to control furnace top pressure and / or recirculate blast furnace top gases.

[0211] Example 13. The iron ore reduction and smelting apparatus of example 12, wherein the apparatus is adapted to provide hydrogen to the gas coming from the gas generator and being fed to the gas to the second injector, and / or to add hydrogen upstream or at the inlet of the reduction gas generator.

[0212] Example 14. The iron ore reduction and smelting apparatus of Example 13, wherein the reducing gas generator comprises a CO2 separator, or / and a catalytic reformer, or / and a non-catalytic reformer, preferably a regenerative reformer without a catalyst configured to provide reducing gas at a temperature of 1100°C or higher, and optionally the reducing gas generator is configured to supply reducing gas to the tuyere level, the shaft level, or both, and the reducing gas generators for the tuyere level and the shaft level may be different.

[0213] Example 15. A method for reducing and melting iron ore in a furnace, comprising the following steps: injecting a superheated reducing agent at a temperature between 1600°C and 2600°C into the furnace at the tuyere level, the volumetric flow rate of the reducing gas injected at the tuyere level being between 500 and 1300 Nm3 / t hot metal, the reducing gas containing 30-100% (vol / vol) H2, having a density between 0.15 and 0.85 kg / Nm3 and a mass flow rate between 300 and 800 kg / t HM, or / and the coke rate of the process being less than 200 kg / t hot metal; thereby providing molten iron.

[0214] Example 16. The method of Example 15, further comprising injecting a reducing agent into the furnace at the shaft level at a temperature between 800°C and 1000°C.

[0215] Example 17. The method of Example 16, wherein the method injects the reducing gas at shaft level substantially along the periphery of the furnace so that gases rising from the agglomeration zone converge at the center of the furnace.

[0216] Example 18. The method according to any one of Examples 15 to 17 for reducing iron ore in a blast furnace, wherein the ratio of the volumetric flow rate of the reducing gas injected at the shaft level to the volumetric flow rate of the reducing gas injected at the tuyere level is between 0:1 and 1:1, preferably between 0.6 and 0.65.

[0217] Example 19. The method of Examples 15-18, wherein the hydrogen in the reducing gas comprises hydrogen produced wholly / partially from renewable energy and / or from natural gas reforming with carbon capture, and / or the reducing gas is heated and / or superheated electrically using wholly / partially renewable energy and / or using lean CO2 electricity such as from nuclear.

[0218] Example 20. The process of Examples 15-19, wherein recycled furnace gas and / or other steelmaking gases are combined with the mixed gas entering the reducing gas generator after or without treatment in a gas scrubber.

[0219] Example 21. The method of Examples 15-20, wherein the reduction gas generator comprises a PSA, VPSA, MEA, or other CO2 separation technology, and a reduction gas compression and heating device, and the device can be arranged in different configurations, preferably capable of compression, separation, and heating.

[0220] Example 22. The method of Examples 15-21, including catalytic and / or non-catalytic modification.

[0221] Example 23. The method of Examples 15-22, wherein the reduction gas generator and / or gas scrubber are at least partially supplied with cold hydrogen.

[0222] Example 24. The process of Examples 15-23, wherein the minimum coke layer thickness is at least 10 cm, e.g., 9-11 cm, or at least 15 cm, e.g., 14-15 cm. [Explanation of symbols]

[0223] 1: Iron ore reduction melting equipment 2: Blast furnace 3: Tuyere level 4: Shaft level 5: Top level 6: First gas injector 7: Reducing gas generator 8: Rock Hopper 9: Second gas injector 10: Hearth 11: Oxygen supply device 12: Gas cleaning equipment 13: Gas sensor 14: Gas injector regulator 15:Abdomen 16, 17: Sensor 21: Coke layer 22: Shaft area with stack 23: Cohesion Zone 24: Dripping Zone 25: Raceway into which gas is injected via tuyere 26: Deadman 27: Shaft injection point for reducing gas 28: Tuyere injection point for oxygen, hot air and / or reducing gas 29: Materials containing ores in various processed forms

Claims

1. An iron ore reduction and melting apparatus, a furnace comprising, from bottom to top, a hearth, a tuyere level, a shaft level and a top level, said furnace comprising at least one first gas injector on said tuyere level; at least one reducing gas generator connected to said at least one first injector, said first injector containing 30 to 100% (vol / vol) hydrogen and 0.15 to 0.85 kg / Nm3 above said tuyere level; ３ and a mass flow rate of 300 to 800 kg / tHM or / and 500 to 1300 Nm ３ and at least one reducing gas generator adapted to provide a reducing gas having a volumetric flow rate of 100 kg / t HM and to operate at a coke rate of less than 200 kg / t hot metal.

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

3. 3. The apparatus for reducing and melting iron ore according to claim 1 or 2, wherein the at least one first gas injector comprises at least one electrically driven heater.

4. The iron ore reduction and melting apparatus according to any one of claims 1 to 3, wherein the at least one first gas injector is adapted to heat the reducing gas to 1600°C to 2600°C, 1800°C to 2600°C, 2000°C to 2600°C, or 2100 to 2200°C.

5. The at least one first gas injector injects 500 to 1300 Nm ３ The iron ore reduction and melting apparatus according to any one of claims 1 to 4, wherein the reducing gas is injected at a volumetric flow rate of / t hot metal.

6. The iron ore reduction and melting apparatus according to any one of claims 1 to 5, wherein the at least one first gas injector is adapted to inject the reducing gas at a pressure of at least 2 bar absolute to at most 10 bar absolute, preferably 4 to 5 bar absolute.

7. The iron ore reduction and melting apparatus according to any one of claims 1 to 6, wherein the at least one electrically driven heater of the at least one first gas injector is adapted to operate with a power of 200 to 600 kWh / t of hot metal.

8. 4. The iron ore reduction and melting apparatus according to claim 3, wherein the heater is an electric resistance heater.

9. The iron ore reduction and melting apparatus according to claim 3, wherein the heater is a plasma torch, and is a plasma torch equipped with an electrode or an electrodeless plasma torch.

10. The iron ore reducing and melting apparatus according to claim 9, wherein the plasma torch is a plasma torch equipped with an electrode, and the iron ore reducing and melting apparatus further includes a plasma torch electrode replacement / repair device adapted to automatically replace at least one used or corroded electrode of the plasma torch with an unused electrode / automatically repair the used electrode with at least one new electrode, or / and the plasma torch is a plasma torch equipped with an electrode, and the iron ore reducing and melting apparatus further includes an electrode paste column or a paste feeder.

11. The iron ore reduction and melting apparatus according to claim 10, wherein the plasma torch electrode replacement / repair device further comprises a magazine for unused electrodes.

12. The iron ore reduction and melting apparatus according to claim 9, wherein the plasma torch is an AC plasma torch, more preferably a three-phase AC plasma torch having three or more than three electrodes, or the plasma torch is a DC plasma torch having two or more than two electrodes.

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

14. 10. The iron ore reduction and melting 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. The apparatus for reducing and melting iron ore according to any one of claims 1 to 14, wherein the blast furnace comprises a plurality of first and / or second gas injectors, the plurality of first and / or second gas injectors being arranged substantially equally spaced and / or circularly, and optionally the outlets of each injector being independent of each other and equally distributed at a distance of 0.5 to 2.5 m, preferably 1.0 to 1.5 m, from each other.

16. CO, CO ２ , H ２ a sensor adapted to analyze the composition of the gas at the top level in terms of concentration, and optionally ２ O, N ２ , or CH ４ The iron ore reduction and melting apparatus according to any one of claims 1 to 15, further comprising a temperature sensor adapted to also analyze the composition of the gas in terms of concentration, and / or to measure the temperature of the gas at the top level, and / or a sensor for humidity measurement after gas cleaning and pre-treatment.

17. 17. The iron ore reduction and melting apparatus according to claim 16, further comprising a gas injector adjusting device configured to adapt the composition of and / or the volume of the gas injected by the first and / or second gas injectors based on the determined gas composition at the top level, and optionally configured to adapt the composition of and / or the volume of the gas based on the composition of the molten iron output by the apparatus and the molten iron production rate.

18. The blast furnace was ３ / t hot metal less than 80Nm ３ / t hot metal less than 40Nm ３ / t hot metal less than 30Nm ３ / t hot metal and inject oxygen below 0 Nm ３ The iron ore reduction and melting apparatus according to any one of claims 1 to 17, further comprising an oxygen supply device adapted to inject hot metal.

19. 19. The iron ore reduction and melting apparatus according to any one of claims 1 to 18, further comprising an oxygen supply device configured to inject oxygen at the tuyere level of the smelting furnace through an oxygen injection port.

20. The iron ore reduction and melting apparatus according to claim 19, wherein the oxygen injection port is disposed within the first injector.

21. The iron ore reduction and melting apparatus according to any one of claims 1 to 20, further comprising a gas scrubbing device, optionally adapted to control the furnace top pressure and / or recirculate the furnace top gas of the blast furnace.

22. 22. The iron ore reduction and melting apparatus according to claim 21, wherein the apparatus is adapted to provide hydrogen to the gas coming from the gas generator and supplied to the gas to the second injector, and / or to add hydrogen upstream of or at the inlet of the reducing gas generator.

23. The reducing gas generator is a CO ２ 23. The iron ore reduction and melting apparatus according to claim 22, comprising a separation device, or / and a catalytic reformer, or / and a non-catalytic reformer, preferably a regenerative reformer without a catalyst configured to provide reducing gas at a temperature of 1100°C or higher, and optionally the reducing gas generator is configured to supply reducing gas to the tuyere level, the shaft level, or both, and the reducing gas generators for the tuyere level and the shaft level may be different.

24. The first injector has a pressure of 0.80 kg / Nm ３ less than 0.60 kg / Nm ３ less than, most preferably 0.30 kg / Nm ３ 24. The iron ore reduction and melting apparatus according to any one of claims 1 to 23, adapted to provide said at least one reducing gas having a density less than

25. 25. The iron ore reduction and melting apparatus according to any one of claims 1 to 24, wherein the first injector is adapted to inject the at least one reducing gas at a total mass flow rate of less than 800 kg / tHM, preferably less than 775 kg / tHM, more preferably less than 750 kg / tHM.

26. 26. The apparatus for reducing and melting iron ore according to any one of claims 1 to 25, further comprising at least one hydrogen content controller supplying reducing gas to the first injector, the hydrogen content controller being adapted to adjust the hydrogen content of the reducing gas to a value of more than 30% by volume, preferably more than 40% by volume, more preferably more than 50% by volume.

27. 27. The iron ore reduction and melting apparatus according to any one of claims 1 to 26, further comprising a second hydrogen content controller that supplies reducing gas to the second injector, the hydrogen content controller being adapted to adjust the hydrogen content of the reducing gas to a value of more than 25% by volume, preferably more than 30% by volume, and more preferably more than 40% by volume.

28. 28. The iron ore reduction and melting apparatus according to any one of claims 1 to 27, further comprising an upstream regulator adapted to control the mass flow rate of the reducing gas injected in the iron ore reduction and melting apparatus at the tuyere level to 800 kg / tHM, preferably less than 775 kg / tHM, more preferably less than 750 kg / tHM, at pressure levels above 2 barg, preferably above 4 barg, more preferably above 5 barg.

29. 29. The apparatus for reducing and melting iron ore according to any one of claims 1 to 28, further comprising an adjusting unit adapted to adjust the average degree of reduction of the iron oxide-containing material reaching the agglomeration zone to a value of more than 85% by controlling the amount and / or composition of the second reducing gas injected through the second injector at the shaft level as a function of the amount and / or composition of the first reducing gas injected at the tuyere level and / or the amount of oxygen injected through the oxygen injection port at the tuyere level.

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

31. The iron ore reduction and melting apparatus according to any one of claims 10 to 14 and 30, wherein the plasma torch is adapted to divide the inflow gas into two flows, in particular into a first flow that flows centrally through the arc generated by the plasma torch and a second flow that flows peripherally around the arc.

32. 1. A method for reducing and melting iron ore in a furnace, comprising the steps of: Injecting a superheated reducing agent at a temperature of 1600°C to 2600°C into the furnace at the tuyere level (the volumetric flow rate of the reducing gas injected at the tuyere level is between 500 and 1300 Nm ３ / t hot metal, and the reducing gas is 30 to 100% (vol / vol) H ２ Including 0.15 to 0.85 kg / Nm ３ and a mass flow rate of 300 to 800 kg / t HM, or / and the coke velocity of the process is less than 200 kg / t hot metal; - thereby providing hot metal.

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

34. The density of the reducing gas at the tuyere level is 0.80 kg / Nm ３ less than 0.60 kg / Nm ３ less than, most preferably 0.30 kg / Nm ３ 34. The method of claim 32 or 33, wherein the

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

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

37. A method according to any one of claims 32 to 36, wherein the reducing gas at tuyere level is heated with one or more electric heaters, preferably in the tuyere stock and / or in the tuyere, before injection into the furnace.

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

39. 39. The method according to any of claims 38, wherein the reducing gas at tuyere level is heated by the one or more plasma torches arranged in the blowpipe of the tuyere stock, the plasma torches being preferably electrode-based or electrodeless plasma torches, such as selected from induction-ignition plasma torches, microwave plasma torches, radio frequency plasma torches, or combinations thereof.

40. 40. The method of claim 38 or 39, wherein the one or more plasma torches are direct current plasma torches and / or alternating current plasma torches and / or three-phase alternating current plasma torches.

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

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

43. The first reducing gas injected at the tuyere level and / or the reducing gas injected at the shaft level are used to convert, by a reforming process, in particular, coke oven gas, natural gas, biogas and / or other hydrocarbon-containing gases into H ２ O, CO ２ , or CO ２ and / or H ２ 43. The method of any one of claims 32 to 42, comprising gases produced by reforming with O-containing gases, more preferably with steel plant off-gases such as smelter furnace top gas, basic oxygen furnace gas and / or open bath furnace gas.

44. The reducing gas at the tuyere level and / or the reducing gas at the shaft level is a molar ratio of (H ２ +CO) / (H ２ O+CO ２ 44. The method of any one of claims 32 to 43, comprising:

45. 45. The method according to any one of claims 42 to 44, wherein the reducing gas at shaft level has a hydrogen content of more than 25% by volume, preferably more than 30% by volume, more preferably more than 40% by volume.

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

47. 47. A method according to any one of claims 42 to 46, wherein the method comprises injecting a reducing gas substantially along the periphery of the furnace at shaft level so that the gas rising from the coagulation zone converges centrally 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 level is controlled to a value above 2 barg, preferably above 4 barg, more preferably above 5 barg.

49. 49. The method according to any one of claims 32 to 48, wherein the reducing gas at tuyere level and the reducing gas at shaft level have a nitrogen content of less than 35% by volume, preferably less than 15% by volume, more preferably less than 10% by volume, and most preferably less than 5% by volume, and further comprising decomposing ammonia to provide the reducing gas injected at tuyere and / or shaft level.

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

65.

51. The hydrogen in the reducing gas comprises hydrogen produced fully / partially from renewable energy and / or from natural gas reforming with carbon capture, and / or the reducing gas is produced fully / partially using renewable energy and / or from lean CO such as nuclear. ２ 51. The method of any one of claims 32 to 50, wherein the heating and / or superheating is performed electrically using electricity.

52. 52. The method according to any one of claims 32 to 51, wherein recycled furnace gas and / or other steelmaking gases are combined with the mixed gas entering the reducing gas generator after or without treatment in a gas scrubber.

53. The reduction gas generator is equipped with a gas separation technology such as PSA, VPSA, MEA, etc., for separating CO2, H2 or other compounds or mixtures thereof, as well as a reduction gas compression and heating device, which can be arranged in different configurations, preferably capable of compression, separation and heating; and the reduction gas generator is equipped with H ２ H that provides ２ The reducing gas generator is provided with a removal device or ２ O and CO, ２ and CO ２ and then CO ２ 53. The method of any one of claims 32 to 52, comprising an adsorbent-enhanced water-gas shift reactor for removing from the output.

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

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

56. 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 from 9 to 11 cm, or at least 15 cm, such as from 14 to 15 cm.

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

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

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

60. 60. The method of any one of claims 32 to 59, further comprising reducing the wall channeling effect of the gas coming 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 in the shaft of the smelting furnace.

61. 42. The method according to any one of claims 38 to 41, wherein the plasma torch is a three-phase AC plasma torch adapted to provide a (gas) velocity within the arc periphery of the plasma torch of 10 to 120 m / s, preferably 15 to 80, more preferably 18 to 60 m / s.

62. 62. The method according to any one of claims 38 to 41 and 61, wherein the plasma torch is adapted to split the incoming gas into two flows, in particular a first flow flowing centrally through the arc generated by the plasma torch and a second flow flowing peripherally around the arc.

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