KR20240113780A - Double shaft furnace device and method of operation of the double shaft furnace device - Google Patents

Abstract

- at least one first shaft 11 and a second shaft 21 extending along the vertical direction Z; Each shaft 11;21 has at least one cooling region C at the bottom 12, 22 of each shaft 11;21, a regeneration region A at the top of each shaft, and a high temperature reduction region B disposed between the regeneration region A and the cooling region C. first shaft 11 and second shaft 21;
- a connecting channel 30 connecting the first shaft 11 to the second shaft 21, wherein the connecting channel 30 extends along the horizontal direction (X), and the connecting channel 30 is connected to the lower end of the high temperature reduction zone B and the first shaft 11 and the second shaft 2 shafts 21 a double shaft furnace device 10 for direct reduction of metal oxides, comprising a connecting channel 30 disposed at the upper end of each cooling zone C,
- A double shaft furnace device 10 in which at least one injection assembly 31 protrudes laterally from the connection channel 30.

Description

Double shaft furnace device and method of operation of the double shaft furnace device

The present invention relates to a double shaft furnace device, in particular a metallurgical double shaft furnace device for the production of directly reduced iron (DRI) and a method of operating said double shaft furnace device.

Industrial metallurgical reduction plants for the production of directly reduced iron, for example plants using the so-called Midrex or Energiron processes, use single shaft furnaces for the direct reduction process. Such shaft furnaces are usually connected to an external reformer, ie a heater.

Reformers, for example CO ₂ - natural gas reformers produce synthesis gas, i.e. a gas containing large amounts of hydrogen and carbon monoxide based on the endothermic reaction between hydrocarbons and CO ₂ in the presence of a catalyst. In the reformer, i.e. during the process of heating the gases, energy is released due to combustion, and part of the combustion energy is "lost", i.e. dissipated due to the emission of flue gases.

The so-called "top gas", i.e. gas with a temperature generally exceeding 300-350°C, is discharged from the top of the shaft (furnace). The top gas, which contains hydrogen, steam, carbon monoxide and carbon dioxide, generally must be quenched during the top gas cleaning process before it can be solubilized for reuse.

Energy is lost due to these operations associated with the process (i.e. reforming or heating the process gas and quenching the overhead gas).

If the process gas composition is not correctly controlled within the heater, the injected natural gas can produce soot or carbon deposits and the heater can become clogged or damaged by so-called metal dust reactions.

Additionally, industrial reduction shaft furnaces are generally expected to introduce hot gases only at one (single) level. Due to this structural arrangement, the solids are regularly overheated around the injection area. As a result, solids begin to melt. As a result, sticking occurs, which reduces the productivity of the furnace.

The object of the present invention is to provide an apparatus and method for the reduction of metal oxides that consume less energy and can further reduce the occurrence of sticking phenomenon.

This object is achieved by a double shaft furnace and a method of operating the same according to the independent claims.

1 is a schematic diagram of a double shaft furnace device according to an embodiment, wherein the double shaft furnace device performs a first step of the method;
Figure 2 is a schematic diagram of a double shaft furnace device according to an embodiment, wherein the double shaft furnace device performs the second step of the method;
Figure 3 schematically shows the form of a Chaudron equilibrium diagram showing the evolution of reducing gases in a H ₂ -H ₂ O environment;
Figure 4 schematically shows the form of a Chaudron equilibrium diagram representing a CO-CO ₂ environment;
Figure 5 schematically shows the form of a Chaudron equilibrium diagram showing that the oxidation degree of the gas decreases significantly when the proportion of recycle gas is doubled;
Figure 6 schematically shows the temperature change of a solid moving on one of the shafts.

A proposed dual shaft furnace device for direct reduction of metal (iron) oxides includes at least one first shaft and a second shaft extending in a vertical direction, each shaft having a cooling region at the bottom of each shaft, each shaft It has a regeneration area at the upper end, and a high-temperature reduction area disposed between the regeneration area and the cooling area. The double shaft furnace device further includes a connecting channel connecting the first shaft to the second shaft, the connecting channel extending along the horizontal direction. The connecting channel is disposed at the lower end of the hot reduction region and the upper end of the cooling region of the first shaft and the second shaft, respectively. The double shaft furnace device further comprises at least one injection assembly projecting laterally from the connecting channel.

The invention is based on the discovery that this specific arrangement of the components of a double shaft furnace device provides advantageous effects and provides an answer to the above objectives.

In contrast to any other known device or method, the present invention provides a solution without hot gas injection from a separate heater or reformer to produce hot reducing gas. Because there are no external (gas-fired) heaters or external (gas-fired) reformers, energy efficiency is significantly improved and common problems associated with such devices such as soot build-up, carbon deposition, metal dust and catalyst poisoning are avoided. do. Heating of the metal ores to be processed and production of high-temperature reducing gases are carried out entirely within a two-shaft furnace device, which significantly improves energy efficiency.

Additionally, since the solids accumulate heat from the gas after the reduction has been carried out during the first stage, and "return" the heat to the recycle gas in the second subsequent stage, the solids, i.e. the metal ores, are deposited in the upper part of the shaft. It is present in and/or in the regeneration area below the top and functions as a regenerative heat exchanger. The top gas temperature is significantly reduced. As a result, less energy is lost in the (following) gas quenching step, and higher energy efficiency is achieved. Additionally, and also to prevent overheating, the solid is cooled by recirculating gas during at least one of the two stages of the operating method.

The proposed device and method also provide a solution to reduce the risk of solids sticking to the shaft. In the proposed double shaft furnace device and corresponding method of operation, the temperature of the reducing gas is controlled, among other things, by injectors located at at least two different heights, i.e. at the height level of each shaft, to prevent the solids from overheating and sticking. are influenced by their location.

Furthermore, because fuel and oxygen are injected into the hot areas of each shaft, less soot or carbon deposits appear or form. In other words, soot or carbon deposition may even be completely avoided. Even if soot or carbon deposits still form, they will not accumulate, at least in the regeneration zone where the dual shaft furnace functions as a heat exchanger, since the solids are permanently replaced during the production cycle.

Furthermore, carbon dioxide (CO ₂ ) produced from a dual shaft furnace device can be captured in a CO ₂ removal plant, i.e., a removal device. Since CO ₂ is not released into the atmosphere, this amount of CO ₂ may be sold or sequestered for industrial applications.

In terms of production of directly reduced iron (DRI) from 93% w/w metallization with natural gas, typical data/parameters that can be expected when the proposed device and method are used are: Natural gas: 10.3 GJ /t.DRI, export gas with a low heating value (LCV) of 10.7 MJ/Nm ³ after CO ₂ removal: 3.2 GJ/t.DRI, net gas consumption: 7.1 GJ/t.DRI, and oxygen consumption: 180 Nm ³ /t.DRI. If the device uses an electric heating device for gas heating (i.e. an electric heating device placed on or within the connecting channel), an input of 60 kWh/t.DRI (0.22 GJ/t.DRI) will reduce the gas consumption by 6.8 GJ/t.DRI, and oxygen consumption can be reduced to 160 Nm ³ /t.DRI. Compared to the commonly known Energiron or Midrex devices, the proposed device and method were found to reduce the amount of CO ₂ emitted by about 18% in kg/tDRI. This amount can be increased to up to 23 % when the connecting channel of the double shaft furnace is equipped with an electric heating device. The following table shows the advantages in an illustrative way:

　 Midrex Energiron HYL double shaft double shaft
plus electric heating
(60kWh/tDRI) 　 GJ/tDRI CO ₂ in kg/tDRI GJ/tDRI CO ₂ in kg/tDRI GJ/tDRI CO ₂ in kg/tDRI GJ/tDRI CO ₂ in kg/tDRI NG input 10,5 585 9,8 548 10,3 578 9,8 549 exhaust gas 0 0 0 0 -3,1 -173,6 -3,0 -168 net gas 10,5 585 9,8 548 7,2 404 6,8 381 %C in DRI 2,5 -92 1,5 -55 - - Direct _CO2 494 493 404 381 Rel. _CO2 difference - -0.2% -18% -23%

“Metal oxide” or “solid” generally refers to materials that are processed in a reduction device such as a blast-furnace or shaft furnace or a direct reduction furnace or similar furnace. The metal oxide may, for example, consist of or include lump ores, pellets, sintered bodies, briquettes, similar materials, or mixtures thereof. Solids can be charged at the top of the shaft and discharged after reduction at the bottom of the shaft. The shaft is generally completely filled with a solid and can be operated in two alternating modes, i.e. in an alternating manner. It is understood that the volume of solids within the shaft may vary depending on the required process conditions.

“Double shaft furnace” generally means a furnace device having at least two shafts with a hollow cross-section, which are connected to each other by at least one structural means, for example a connecting channel. In either case, the dual shaft furnace includes a first shaft and a second shaft disposed in parallel with the first shaft.

“Vertical direction” generally means a direction perpendicular to the ground. In particular, the vertical direction may be defined by at least one length dimension of the shafts.

“Horizontal direction” generally means a direction parallel to the ground, and/or perpendicular to the vertical direction. In particular, the horizontal direction can be defined by the length dimension between the shafts. The connecting channel extends in the horizontal direction.

“Top gas” generally refers to gas that may escape from the top of the shaft during operation. For example, the top gas may contain at least (in mole percent) about 16% carbon monoxide (CO), 12% carbon dioxide ( _CO2 ), 52% hydrogen ( _H2 ), and 20% water ( _H2O ). You can. Top gas composition may vary depending on the type of fuel.

“Export gas” generally means that portion of the overhead gas that has passed through a gas cleaning device and can be discharged to other (industrial) equipment.

"Recycle gas", i.e. syngas or reduction gas, generally means a gas mixture that is recycled, i.e. used to initiate the reduction of metal ores, for example, the recycle gas usually has at least (in mole percent) about Contains 22% carbon monoxide (CO), 1% carbon dioxide ( _CO2 ), 74% hydrogen ( _H2 ) and 3% water ( _H2O ). Recycle gas composition may vary depending on the type of fuel.

The double shaft furnace device can be operated as a recirculating device, and the expression "gas" therefore generally refers to the gases produced, transported, processed and/or changed in composition while they move through the double shaft furnace device in particular. means in fact all the types of gases or gas compositions mentioned above.

Each shaft of a double shaft furnace device can be described by the structure of its internal regions, where each region performs different reactions, ie has a different function/purpose. The shaft of each furnace has substantially at least three different zones, one above the other. The lowest region is located within or above the bottom of the shaft and is referred to as the cooling region. Above the cooling zone, the high-temperature reduction zone begins. The regeneration zone is located above the hot reduction zone and is at the top of the furnace. The shaft may have a height of 20 to 40 meters, preferably 26 to 30 meters. Each shaft may comprise one or more oxyfuel injectors, i.e. injectors, which have an outlet defining a junction level between the regeneration zone and the hot reduction zone. Each oxyfuel injector extends at least partially in a vertical direction. The vertical direction is the direction perpendicular to the ground.

The terms “top”, “bottom”, “bottom” and “top” refer to vertical positions extending from the ground/bottom. For example, the lower section of the furnace may be the bottom of the shaft or a proximal section or portion thereof.

“Cooling zone” may generally mean an area and/or space within a shaft, particularly in the “lower” end portion of the shaft.

“Bottom” generally refers to the lower part of the shaft, i.e. the lower section. The bottom contains the cooling area of the shaft.

“Play area” generally means an area or space within a shaft at or below the top of the shaft. In other words, the upper part of the shaft contains a regeneration area.

“High temperature reduction zone”, i.e. “reduction zone” generally means the area or space between the regeneration zone and the cooling zone. At the beginning of the hot reduction zone, i.e. at or proximal to the height/level bordering the reduction zone and the regeneration zone, also known as the "junction level", fuel and oxygen are introduced through injectors to form a "hot reduction gas" or It can be injected through a gas lance of an injector, or preferably through an oxyfuel injector, which makes it possible to heat the metal oxide. Accordingly, the reducing gas supplies the energy required for the reduction reaction. Partial oxidation of hydrocarbon fuels and/or recycle gases produces mostly carbon monoxide (CO) and hydrogen (H ₂ ).

The location of the discharge portion of the oxy-fuel injector, i.e., each oxy-fuel injector of the plurality of oxy-fuel injectors, may define the height/level of the regeneration area with respect to the bottom (level). The location of the outlet therefore allows controlling the residence time within each zone and determining the amount of heat transferred between the gas and solid.

The volume of oxygen injected can be adjusted to obtain a reducing gas temperature in the range of 800°C to 1050°C, preferably in the range of 920°C to 950°C, which prevents melting and sticking of the iron oxide. It has been confirmed that it can be reduced or at least significantly reduced. The solids (going down through the regeneration zone) enter the hot reduction zone with a temperature of 650°C to 850°C. This temperature level is high enough to prevent soot or carbon deposits, which could otherwise cause clogging after a period of time. In the lower part of the reduction zone, i.e. when entering the cooling zone, the solid generally has a temperature in the range of 800°C to 950°C. The temperature must be adapted to the properties of the solid. At the end of the reduction zone, i.e. at the height/level at which the upper part of the cooling zone is in contact with the lower part of the reduction zone, the hot reducing gas from the top mixes with the warm (recirculating) gas from the bottom and flows through a connecting channel. You can move.

“Connecting channel” may generally mean a structural element disposed between a first shaft and a second shaft. The connecting channel is configured to allow the first shaft to be in substantially resistanceless fluid communication with the second shaft, thus allowing gas to flow freely from one shaft to the other depending on the respective pressure conditions. In other words, gas can flow from the first shaft to the second shaft through the connecting channel, and vice versa. The connecting channel extends generally in a horizontal direction and is disposed at least partially at the lower end of the reduction region of each of the first and second shafts. In other words, the connecting channel has one end portion partially overlapping with the "lower" portion of the hot reduction zone of the first shaft and the upper portion of the "cooling zone" and the lower portion of the hot reduction zone and the cooling zone of the second shaft. It has another distal portion that partially overlaps the upper portion of.

The connecting channel is provided with at least one injection assembly. The injection assembly may, for example, consist of or comprise an oxyfuel injector, allowing for the introduction of additional reducing gas and the moving gas through the hot air connection channel. Additionally or alternatively (as a variant) the injection assembly, i.e. the "injector", may consist of or include an electrically heated syngas injector and/or a plasma torch for injecting the hot syngas and/or recycle gas into the connecting channel. You can. Additionally, some electrical heating devices, for example electrical radiant tubes, may be placed in the connecting channel. Additionally or alternatively, the injection assembly may consist of or include at least one oxygen injector and at least one fuel injector disposed proximal to one another.

Due to the injection assembly, the gas passing through the connecting channel is heated further, thereby increasing its ability to carry out the reduction reaction. This device makes it possible to control and/or influence process parameters, in particular the temperature and/or composition and/or volume of the gas flowing into one of the shafts. As a result, the process conditions of the shaft through which the gas is conveyed can be accurately controlled by the oxyfuel injector. In other words, because of the connecting channel and the oxy-fuel injector, the process conditions and parameters of at least one of the shafts, in particular the shaft through which the gas flows after passing through the oxy-fuel injector, are controlled, so that they change the process conditions of the shaft through which the gas flows. and parameters may be different. It should also be noted that the arrangement of one or more electric heating devices, such as electric radiation tubes, can contribute to, ie influence, the precise control of process conditions and parameters.

The expression “injector”, i.e. “injection device” or “injection assembly” generally means a device for introducing/injecting a medium, for example a gas, liquid, powder, fuel or fluid. The injector may be configured to inject oxygen and/or fuel and/or a reducing agent such as CO or H ₂ , for example at a certain temperature. Additionally or alternatively, the injector may also be configured to inject nitrogen or other components. For example, the connecting channel is one or more injector assemblies, preferably on the side or wall of the connecting channel, from or through which the connecting channel protrudes laterally, i.e. in the direction of the channel, into its inner space. It may be provided with one or more injectors. Furthermore, for example, the injector disposed in particular at the upper end of each shaft may comprise a feeder, for example a feeder projecting laterally or along a substantially horizontal direction of the shaft, wherein such injector may further comprise a gas lance connected to or integrated with the supply, wherein the gas lance may extend along a direction other than the horizontal direction, for example a vertical direction.

“Fuel” may generally mean a combustion medium comprising at least one of the following: hydrogen, hydrocarbons, alcohols, ammonia, or compounds derived therefrom, or mixtures thereof.

Due to the laterally protruding injection assembly of the connecting channel, injection of additional fuel and oxygen is effected, different from the level of the first fuel and oxygen injection resulting from the outlet of the plurality of oxyfuel injectors extending vertically within each of the shafts. It can be. Injection at these different positions and height levels allows the parameters of reducing gas quantity temperature and composition to be generated and controlled. Additionally, the reducing gas temperature can be adjusted and/or controlled particularly quickly and effectively. The gas temperature and gas composition in the connecting channel can be adjusted in particular to control the process parameters and conditions under which the reduction reaction of metal oxides occurs in adjacent shafts.

At least one injection assembly protruding into the connecting channel may be arranged laterally of the connecting channel. For example, the injection assembly may be disposed at the upper end of the connecting channel, but it should be noted that the placement of the injection assembly or its different elements is not limited to the upper portion. The injection assembly may include at least one oxyfuel injector and/or an electrically heated syngas injector and/or a plasma torch.

The oxyfuel injector may, for example, consist of or include an assembly of one or more pairs of lances. “A pair of lances” generally means a combination consisting of or including at least one fuel lance and at least one oxygen lance. Preferably the pair of lances form or comprise coaxial lances, in particular two coaxial lances, the coaxial lances forming an arrangement of two pipes, wherein one small diameter pipe, i.e. the first lance, is connected to the larger pipe. diameter pipe, i.e. inserted into the second lance. Coaxial lances can improve partial combustion of fuel and oxygen, especially compared to a two single injection lance system. In this context, the expression “coaxial” refers to the common axis of the two lances. In other words, the two pipes share one common axis.

In a first embodiment, the injection assembly consists of or includes at least one of the following: an electrically heated syngas injector, a plasma torch for spraying hot syngas, and an oxyfuel injector. An electrically heated syngas injector may refer to a device configured to heat a medium such as syngas by electric power. “Plasma torch” generally refers to a plasma generating device configured to inject syngas and/or recycle gas into a channel. “Oxygen fuel injector” generally refers to an injector that injects a mixture of oxygen and fuel, or allows injecting oxygen and fuel simultaneously.

In another embodiment, the dual shaft furnace further comprises an electric heating device consisting of or comprising a plurality of electric radiant heating tubes, where the electric heating tubes are disposed in a connecting channel. The tube may, for example, be substantially cylindrical, or may have a round cross-sectional shape. It is understood that tubes may also exist in other forms. Electric heating devices, i.e. electric radiant heating tubes, allow the gas mixture flowing past the connecting channel to be further heated. In particular, the electric heating device allows the parameters of the gas mixture and the process parameters of the shaft through which the gas mixture flows to be controlled more accurately. Additionally, the radiant heating tubes also allow to influence the combustion reaction of fuel and oxygen taking place within the connecting channel. In any case, the electric heating device allows gases to flow substantially resistance-free through connecting channels from one shaft furnace to another. The expressions "substantially without resistance" or "without resistance" mean that the connecting channel is preferably permanently open to the passage of gas, and the flow of gas through the connecting channel is preferably controlled by a flow control device such as a valve or the like. This means that it is not blocked or restricted.

In another embodiment, each shaft includes at least one bottom recycle gas inlet and at least one top recycle gas inlet. “Inlet” may generally mean an opening or injection portion or similar structure configured to transport and/or inject recirculated gas into the respective shaft. The upper recirculation gas inlet may consist of or include an opening at the top of the shaft. The clearance at the top of each shaft allows the top recycle gas to be distributed evenly before flowing through the solids.

“Recycle gas” generally means a gas that may be enriched in CO and/or H ₂ at a temperature close to ambient temperature. The recycle gas may have a temperature range between 40°C and 80°C. The recirculating gas can reheat itself in contact with solids, especially when injected from the top of the shaft. The (recirculating) gas can also be heated when introduced into the high temperature reduction zone due to the fuel and oxygen being injected. Additionally, the reducing gas flows into the connecting channel due to the injected fuel and oxygen and/or due to the high temperature syngas from the electrically heated injector, and/or due to the high temperature syngas from the plasma torch, and/or due to the electrical radiation tube inside the connecting channel. It can be heated as it passes through.

In another embodiment, each one of the first shaft and the second shaft has a plurality of oxy-fuel injectors disposed at least partially along a vertical direction for injecting oxygen and fuel into the hot reduction region of each shaft. In other words, each one of the first shaft and the second shaft has a plurality of oxygen-fuel injectors for injecting oxygen and fuel into each shaft. The oxyfuel injector may include a lance that injects oxygen and fuel into the high temperature reduction zone. In particular, each oxyfuel injector of the plurality of oxyfuel injectors may further include an oxygen supplier and a fuel supplier, and the suppliers protrude horizontally above the regeneration area of each shaft toward the upper end (i.e., free space). A vertically extending (oxygen-fuel) lance can be connected in the upper part to both the oxygen supply as well as the fuel supply. The oxyfuel lances may be provided with an opening at their tip, i.e. at the distal section, and the opening is disposed at the beginning of the hot reduction zone, so that oxygen and fuel are injected into the hot reduction zone.

The feeder, which can be formed from pipelines, can be integrated with each oxyfuel lance, or can supply a plurality of connected oxyfuel lances. Because of the oxy-fuel injector, the oxygen and fuel can be dissipated at or near the center of the shaft, or at other locations on the shaft, so that the reducing gas is distributed uniformly and the creation of hot spots and/or cool areas. This can be effectively prevented. Because the lances are arranged along the vertical axis of each shaft, there are no mechanical constraints induced by the charge passing along the lances, except for slight friction. In order to further reduce the effect of friction of the descending charge, i.e. solids, the lances may have a particularly thin shape, i.e. of a particularly small diameter.

In other words, each shaft may have a plurality of oxy-fuel injectors extending at least partially along the vertical direction into the regeneration zone, each oxy-fuel injector of the plurality of oxy-fuel injectors being disposed at an upper end portion of the hot reduction zone. It has an outlet. Because of oxyfuel injectors, fuel and oxygen can be dissipated at different locations at the same elevation level. Additionally, the oxyfuel injector tips define, among other things, the height level of the junction level, i.e. the boundary between the hot reduction zone and the regeneration zone.

In another embodiment, each oxyfuel injector of the plurality of oxyfuel injectors is fluidly and/or hermetically connected to an oxygenator and a fuel supplier. The oxyfuel injectors disposed in the channels as well as the oxyfuel injectors disposed at the top of each shaft furnace may be fluidly and/or hermetically connected to one or more oxygen feeder(s) and fuel feeder(s). You can. The expression “gas-tight” generally refers to a connection constructed to provide a closed fitting that prevents pressurized, hazardous and/or explosive gases from terminating the connection.

In another embodiment, a first gas-tight valve is disposed upstream of the fuel supply and downstream of the fuel supply, a second gas-tight valve is disposed upstream of the fuel supply and downstream of the recycle gas supply, and a third gas-tight valve is disposed upstream of the fuel supply and downstream of the recycle gas supply. The gas-tight valve is disposed upstream of the oxygen supply and downstream of the oxygen supply, and optionally a fourth gas-tight valve is disposed upstream of the oxygen supply and downstream of the nitrogen supply, and a fifth gas-tight valve is disposed upstream of the oxygen supply. It is arranged upstream and downstream of the recirculation gas supply.

“Recycle gas supply” may mean a recycle gas pipeline or similar device that stores recycle gas. Due to this device, the oxyfuel injector can inject fuel and/or oxygen and/or recirculated and/or nitrogen gas alternately or simultaneously. It should be noted that the injection of recirculating gas may have the purpose of protecting, i.e. cooling, the lance, especially when the shaft is in regenerative mode. Alternatively or additionally, recirculating gas may be injected at the top of each shaft. It should be noted that when the operating mode of the shaft is changed, nitrogen is injected into the feeder for a short period of time, thereby flushing the injector and thus avoiding the hazard.

In another embodiment, each oxygen supplier is fluidly and/or hermetically connected to a minor supply, each fuel supplier is fluidly and/or hermetically coupled to a fuel supply, and each oxygen supplier and each fuel supplier are fluidly and/or hermetically connected to a fuel supply. is fluidly and/or hermetically connected to at least one recycle gas top inlet or at least to the recycle gas pipeline.

In another embodiment, each one of the first shaft and the second shaft has at least one gas outlet connected to at least one upper gas pipeline for conveying the upper gas to the gas cleaning device, each gas outlet each is disposed at the upper end of the shaft, and the upper gas pipeline has a gas outlet connected to the gas cleaning device. “Gas outlet” generally means any kind of structural element that allows gases to exit the shaft. For example, the gas outlet may take the form of a pipeline. The double shaft furnace device may include or be connected to a gas cleaning device. “Gas scrubbers” typically include dust collectors and/or bag filters and/or electrostatic precipitators and/or wet scrubbers that remove solids/dust from the overhead gas and cool the overhead gas to 25-50°C. refers to a gas cleaning plant that Cooling of the top gas also reduces the water content.

In another embodiment, a gas cleaning device includes: a wet scrubber to collect overhead gas dust to quench the gas and (thereby) remove water; and optionally a dry dust collection unit placed upstream of the wet scrubber. Here, the dry dust collection unit includes at least one of the following: dust collector, cyclone, bag filter, and electrostatic dust collector. Wet scrubbers allow the top gas dust to be collected and discharged individually as sludge.

In another embodiment, the dual shaft furnace device may further include a CO ₂ removal device for removing carbon dioxide from the gas discharged by the gas cleaning device, the removing device being hermetically connected downstream of the gas cleaning device. and are placed. The double shaft furnace device may include a CO ₂ removal device for removing carbon dioxide from the gas discharged by the gas cleaning device, the removing device being hermetically disposed downstream of the gas cleaning device. The CO ₂ removal plant can have two exhaust streams. One stream carries recycle gas rich in CO and H2, and the second stream carries captured _CO2 . The captured CO2 gas can be sold for industrial applications, sequestered, stored and, if necessary, vented to the atmosphere.

In another embodiment, the removal device and/or a compression unit for compressing the recycle gas disposed downstream of the removal device discharges recycle gas having a temperature in the range of 40°C to 120°C and has a recycle gas conveying device. The pipeline is connected to and/or integrated with each bottom recycle gas inlet and/or each top recycle gas inlet and/or the oxygen supply and/or the fuel supply. The dual shaft furnace device may include a compression unit disposed downstream of the CO ₂ removal device. Due to the compression performed by the compression unit, the recycle gas can have a temperature ranging from 40°C to 120°C. The recirculation pipeline collecting the recycle gas is connected to and/or integrated with the bottom recycle gas inlet and/or the top recycle gas inlet and/or the oxygen supply and/or the fuel supply.

The invention also relates to a method of operating a double shaft furnace device. The method includes, in a first step, injecting oxygen and fuel into the high-temperature reduction zone of the first shaft, injecting recirculating gas into the upper end of the first shaft, and into at least one injection assembly protruding laterally of the connecting channel. Injecting oxygen and fuel into the connection channel, charging metal oxide into the second shaft, extracting upper gas from the upper part of the second shaft, and extracting metal product from the bottom of the second shaft. In a second step, injecting oxygen and fuel into the high temperature reduction region of the second shaft, injecting recirculating gas into the upper part of the second shaft, and injecting oxygen and fuel into the connection channel with at least one injection assembly. charging metal oxide into the first shaft, extracting top gas from the top of the first shaft, and extracting metal product from the bottom of the first shaft.

In other words, in the first stage, recycle gas is injected from the top of the first shaft. Oxygen and fuel are injected into the high temperature reduction zone of the first shaft. At the same time, a small volume of recirculating gas is injected through the lance of the second shaft, and the produced top gas is collected from the second shaft. Oxygen and fuel are injected into the connecting channel. Metal oxides are charged to the second shaft and metal products are extracted from the bottom of the second shaft. In the second stage, recycle gas is injected from the top of the second shaft, oxygen and fuel are injected into the high temperature reduction zone of the second shaft, and recycle gas is injected through the lance of the first shaft. In the second stage, the top gas is collected from the first shaft. As in the first stage, oxygen and fuel are injected into the connecting channels. Metal oxide is charged into the first shaft and metal product is extracted from the bottom of the first shaft.

The above-mentioned improvements and embodiments of the double shaft furnace device also apply to the operating method of the double shaft furnace device.

Since the operating method of the double shaft furnace is carried out on the basis of two stages, the two shafts are operated in an alternating manner.

In an embodiment, the method further comprises a first step and a second step of heating the gas flowing through the connecting channel by means of an electric heating device. The gas mixture flowing through the connecting channel can be further heated by an electric heating device, i.e. an electric radiation tube, which more accurately determines not only the process conditions, but also the temperature of the gas mixture flowing through the connecting channel and the parameters of the shaft through which the gas mixture is conveyed. makes it possible to control

In an embodiment, the metal oxide has a temperature ranging from -15°C to 40°C, preferably from 15°C to 30°C, and most preferably from 25°C; and/or the metal product has a temperature range of 120°C to 700°C; The top gas has a temperature in the range of 80°C to 250°C, preferably in the temperature range of 130°C to 170°C, most preferably 150°C.

In another embodiment, in a first stage, the recycle gas can be injected at the top of the first shaft at a first pressure, and the top gas can be discharged at the top of the second shaft at a second pressure, and the second In a step, the recycle gas may be injected at the top of the second shaft at a first pressure, and discharged at the top of the first shaft at a second pressure, the first pressure being higher than the second pressure; and optionally the pressure difference, i.e. the first pressure minus the second pressure, may range from 1.5 to 3.5 bar, preferably from 2.0 to 2.5 bar. The pressure difference is mainly affected by the permeability of the charge and the size distribution of the solid.

In another embodiment, the method further comprises: transporting the upper gas via an upper gas pipeline to a gas cleaning device arranged downstream of the plurality of shafts, the (cleaned) upper gas from the gas cleaning device conveying to a CO ₂ removal device disposed downstream of the gas cleaning device, and conveying the recycle gas to a plurality of shafts through a recirculation pipeline.

In another embodiment, the method further comprises: compressing the recycle gas by a compression unit disposed upstream of the recycle pipeline and downstream of the CO ₂ removal device.

Additional aspects and features of the invention are derived from the following description of the dependent claims, accompanying drawings and embodiments.

Embodiments of the invention are now explained by way of example and with reference to the accompanying drawings.

Figure 1 shows a schematic view of a double shaft furnace device 10 according to an embodiment, where the double shaft furnace device 10 carries out the first step of the method, while Figure 2 schematically shows the second step.

As can be seen from FIGS. 1 and 2, the double shaft furnace device 10 includes two hollow shafts 11 and 21, with reference numeral 11 designating the first shaft and reference numeral 21 designating the second shaft. The two shafts 11 and 21 extend along the vertical direction Z. Each shaft has three different zones consisting of a regeneration zone A, a cooling zone C and a hot reduction zone B above the cooling zone C and below the regeneration zone A. As shown, cooling area C is delimited in part by bottom 12 of shaft 11 and bottom 22 of shaft 21. Play area A is delimited by upper part 13 for shaft 11 and upper part 23 for shaft 21.

The connection channel 30 fluidly connects the bottom, i.e., lower section, of the high-temperature reduction region B of the first shaft 11 and the bottom, i.e., lower section, of the high-temperature reduction region B of the second shaft 21 along the horizontal direction X. As shown, at least one injection assembly comprising an oxyfuel injector 31 protrudes laterally into the connecting channel 30 . It should be noted that the electric heating device may further be provided comprising a plurality of electric radiation tubes 32 (shown schematically in FIGS. 1 and 2) in the connecting channel 30. The injection assembly may further include an electrically heated syngas injector (not shown). Additionally, the injection assembly may further include a plasma torch 33 for injecting hot syngas and/or recycle gas.

As further shown in Figure 1, each shaft 11, 21 includes one or more bottom recycle gas inlets 14, 24 and top recycle gas inlets 15, 25.

Additionally, each shaft 11 and 21 has a plurality of (oxygen fuel) injectors, where each injector includes a feeder and a lance connected to the feeder. The oxygen feeders 16, 26 and the fuel feeders 17, 27 protrude along the horizontal direction Lances 18 and 28 extend along the vertical direction Z through the regeneration area A. The oxyfuel injectors, i.e. lances 18 and 28 of the oxyfuel injectors, have their respective outlets at the upper end of the hot reduction zone B.

As can be derived from FIGS. 1 and 2, each shaft 11, 21 also has a gas outlet 19, 29 connected to an upper gas pipeline 41 that conveys the upper gas to a gas cleaning device 42. Gas outlets 19 and 29 are disposed/located at the upper ends 13 and 23 of the respective shafts 11 and 21.

Reference numeral 51 denotes a CO ₂ removal device for removing carbon dioxide from the gas discharged by the gas cleaning device 42. The CO ₂ removal device 51 is hermetically connected to the cleaning device 42 by a pipeline 43. The CO ₂ removal device 51 is located/arranged downstream of the gas cleaning device 42. CO ₂ device 51 discharges CO ₂ -free gas (rich in CO and H ₂ ) in pipeline 52 and CO ₂ gas in CO ₂ gas pipeline 53 . Additionally, a compression unit 61 arranged downstream of the CO ₂ removal device 51 is connected to the CO ₂ removal device 51 by a CO ₂ -free gas pipeline 52 and recycle gas having a temperature range of 40°C to 80°C. emits. In this context, the export gas pipeline 54 is connected to the CO ₂ -free gas pipeline 52 , which is arranged between the CO ₂ removal device 51 and the compression unit 61 to allow excess gas to be exported if necessary.

The recycle gas pipeline 62, which collects the recycle gas leaving the compression unit 61, is connected to the upper recycle gas inlets 15 and 25 and the bottom recycle gas inlets 14 and 24, as well as the oxygen supply 16, 26 and the fuel supply 17, 27. . It should be noted that the connection between the nitrogen supply and the oxygen supply 16, 26 is not shown in Figure 1.

In the first step, as shown in Figure 1, metal oxide is poured into the second shaft 21 through the upper end 23 of the second shaft 21. The recirculating gas delivered from the compression unit 61 is injected through the gas inlet 15 at the top of the first shaft 11. Oxygen and fuel are injected from oxygen supplier 16 and fuel supplier 17 of shaft 11, respectively. The lance 18 of the injector transports the oxygen and fuel to the upper part of the hot reduction zone B of the first shaft 11 where they are ignited. The gas produced at the opening of lance 18, i.e. proximal thereof, is diluted with recycle gas, thereby producing a hot reducing gas. In the first stage, the recycle gas is also injected into the cooling zone C above the bottom 12 of the first shaft 11 and also into the cooling zone C above the bottom 22 of the second shaft 21.

At the same time, traces of recirculating gas are injected into the oxygen supply 26 and the fuel supply 27 of the second shaft 21, whereby the corresponding injectors, i.e. the lances 28 connected to the supplies 26, 27, are cooled and thus protected from heat and internal blockage. do. The “trace” amount of recycle gas injected through fuel supplies 26 and 27 is less compared to the amount of gas injected through oxygen supplies 16 and 17.

After reacting with the metal oxide in the hot reduction zone B of the first shaft 11, the hot reducing gas is mixed with the recirculating gas coming from the cooling zone C of the first shaft 11. The mixture is introduced into connecting channel 30ㅇ. Due to the injection assembly comprising the oxy-fuel injector 31, an additional amount of oxygen and fuel is injected into the connecting channel 30, which in particular adjusts the temperature and composition of the hot reduction gas before introduction into the hot reduction zone B of the second shaft 21. makes it possible.

At the bottom of the hot reduction zone B of the second shaft 21, the hot reduction zone coming from the connecting channel 30 is mixed with the recirculation gas coming from the cooling zone C of the shaft 21. The hot reduction gas passes through the hot reduction zone B of shaft 21, reducing the iron oxide to metallic iron. While flowing upward on the second shaft 21 in the direction of regeneration area A, the hot reducing gas reacts with the iron oxide by performing a preliminary step of reduction and transfers its heat to the solid. During the first stage, upon deployment/i.e. reducing gas is extracted from the upper part 23 of the second shaft. At the end of the first step, the metal product is extracted, ie discharged, from the bottom 22 of the second shaft 21.

It should be noted that the injection assembly comprising the oxy-fuel injector 31 in the connecting channel 30 is controlled in such a way that the passing reducing gas is heated to a preset temperature before the gas is introduced into the second shaft 21. Such control can be achieved, for example, by measuring the temperature at both ends of the connecting channel 30 and/or by precisely defining the amount of fuel and/or oxygen injected into the connecting channel 30. Accordingly, the process conditions of the second shaft 21 are influenced by the injection of fuel and oxygen into the connecting channel 30, ie can be precisely adjusted thereby. In this context, an electric heating device comprising a radiation tube 32 as well as a plasma torch 33 and/or an electrically heated synthesis gas injector makes it possible to adjust the conditions of the passing gas and process parameters.

It should be noted that the same applies to the first shaft 11 during the second stage. At the end of the first stage, a transition to the second stage is performed. In other words, after a predetermined period of time, for example 20 to 60 minutes, the operating mode of the double shaft furnace device is switched from the first stage to the second stage. In other words, the two steps are performed in an alternating manner.

As shown in Figure 2, in the second stage, the metal oxide is discharged through the upper section of the first shaft 11. In the second stage, the solids in the regeneration area of the first shaft 11 will accumulate the heat transferred from the reducing gas before the gas is discharged from the top of the shaft 11, while the second shaft 21 regenerates it within its regeneration area A. It operates to heat the recirculating gas injected from the upper part 23. Oxygen and fuel are injected through the oxyfuel injector, i.e., the lance 28 of the oxyfuel injector, at the top of the high temperature reduction region B of the second shaft 21. Recirculating gas is also injected into the cooling zone C above the first shaft bottom 12 and the second shaft bottom 22. At the same time, a small amount of recirculating gas is injected into the oxygen supply 16 and fuel supply 17 of the first shaft 21 to protect the oxy fuel injector 18 from heat and internal clogging.

As in the first stage, oxygen and fuel are injected into the connecting channel 30 by the injection assembly 31, and the moving gas can be further heated by hot gas injected by the plasma torch 33 and/or by the radiation tube 32. This makes it possible to adjust and/or control the parameters of the hot reducing gas, such as the temperature of the gas, and also makes it possible to adjust and/or control the process parameters in the first shaft 11. In the second stage, the top gas is extracted from the upper part 13 of the first shaft 11, and the metal product is discharged from the bottom 12 of the first shaft 11.

Before they are charged to one of the shafts, the metal oxides have an ambient temperature of about 25°C, and the metal product discharged from the shaft has a temperature range from 120°C to 700°C. The metal product is generally cooled to about 120°C and then stored for further use. However, in some cases, the metal product can be extracted at a temperature of about 700°C, and then produced either high-temperature briquette iron (HBI) or high-temperature directly reduced iron (HDRI), which can be introduced directly into the furnace. It can be used directly at that temperature to do so. When the overhead gas is extracted during the first or second stage, it has a temperature of approximately 150°C.

Therefore, one additional advantage of the equipment and process is that, except when HBI or HDRI is produced, no hot elements (gases or solids) are introduced into the furnace and no hot elements (gases or solids) are introduced into the furnace. ) is not extracted from the furnace.

In both the first stage and the second stage, the upper gas is conveyed through the upper gas pipeline 41 to the gas cleaning device 42 disposed downstream of the shafts 11 and 21. After the gas has been cleaned and discharged from the gas scrubber 42, the gas, sometimes also referred to as “washed top gas”, is further conveyed to the CO2 removal device 51. Accordingly, the CO ₂ removal device 51 is disposed downstream of the gas cleaning device 42. In the CO ₂ removal unit 51 , carbon dioxide is removed and the remaining gas, also referred to as (re)circulation gas, is conveyed via a recirculation pipeline 62 via a compression unit 61 to shafts 11 and 21 .

After passing through the hot reduction zone B, the solid enters the cooling zone C, and leaves the shaft furnace at a defined temperature for the next subsequent process. The temperature of the solids exiting the shaft furnace is adjusted by injecting the correct amount of recycle gas at the bottoms 12 and 22 of each shaft through bottom recycle gas inlets 14 and 24.

After a certain period of time, the solids in the regeneration area A of the second shaft 21 will absorb enough heat, and the upper gas temperature in the upper part of the second shaft 21 will exceed a certain limit. At this point, the transition from the first stage to the second stage begins. Metastasis may occur after 20 to 60 minutes.

During the first and/or second stage, the volume of oxygen is adjusted to an amount exceeding the partial oxidation stoichiometry, which allows to obtain the desired range of 920 °C to 950 °C for the reducing gas temperature, and further soot. To prevent the formation and deposition of carbon. In addition, the oxidation degree of the gas given by the ratios of CO ₂ /(CO+CO ₂ ) and H ₂ O/(H ₂ +H ₂ O) is reduced according to the Chaudron equilibrium diagram as shown in Figures 3 and 4. It must be low enough to comply with the conditions. According to the Chaudron equilibrium diagram shown, complete reduction of iron oxide takes place at 950° when the CO ₂ /(CO+CO ₂ ) ratio in the reducing gas is less than 0.3 and the H ₂ O/(H ₂ +H ₂ O) ratio is less than 0.4. It can be achieved in C. Therefore, the amount of CO or H ₂ introduced into the shaft furnace must be much higher than the stoichiometric amount required for the chemical reaction of reduction of the metal oxide.

In other words, CO ₂ and H ₂ O generated during the reduction reaction must be maintained in a sufficiently diluted state. The degree of dilution of CO ₂ and H ₂ O is kept high by increasing the amount of recycle gas (rich in CO and H ₂ ) injected from the top of the shaft. Accordingly, a large portion of the overhead gas is recycled after the H ₂ O has been removed in the gas scrubbing device and after the CO ₂ has been removed in the CO ₂ removal device. The driving force for the reduction reaction kinetics is the deviation of the oxidation degree of the reducing gas from equilibrium, as shown in the diagram.

Figure 5 shows that the oxidation degree of the gas decreases significantly when the proportion of recycle gas injected upward is doubled. Surprisingly, it was found that doubling the rate of recycle gas injected upwards only increased net energy consumption by 1.4%.

An additional advantage of a regenerative double shaft reduction furnace is that significant quantities of gas can be recirculated without affecting the energy consumption of the furnace. In practice, the energy required to heat, for example, an additional volume of recycle gas injected into the top of the first shaft 11 is recovered, for example in the regeneration zone A of the second shaft 21, before the gas is discharged from the furnace 10.

Figure 6 shows the temperature of one solid moving down a shaft from the top to the bottom. As derived, the solid has a starting temperature (at the top) of about 25 °C, and the gas may have a temperature of about 100 °C in the upper section. In regeneration zone A the solid is heated.

Depending on the amount, composition and temperature of the gases as well as the number of (operational) cycles performed by the double shaft furnace, a generally increasing, sawtooth-shaped temperature curve is formed for the gases as well as the solids passing through the regeneration zone A. Therefore, it should be noted that the two curves represent a function of the distance between the starting point of the solid part in the shaft and its actual position. While passing through the hot reduction zone B, the gas temperature as well as the temperature of the solid piece fluctuates around a temperature between 800°C and 900°C, thus forming another sawtooth-shaped temperature curve. Likewise the variation is influenced by the number of switching of the operating cycle of the double shaft furnace.

When introduced into cooling zone C, the solid piece typically has a temperature of about 850°C to 880°C. In the cooling zone C, the solid piece is continuously cooled, so that the solid piece has a temperature of about 100°C to 130°C at the bottom (part) of the shaft. The temperature of the surrounding gas in the cooling zone C increases with increasing distance from the bottom of the shaft, i.e. gradually decreases with decreasing distance from the bottom of the shaft. In cooling zone C the surrounding gas has a temperature lower than that of the solid piece.

The described embodiments are examples of the invention. The individual configurations of each embodiment represent individual features of the invention, are considered independently of each other, and further develop the invention independently of each other. Accordingly, the features are also considered to be constitutive of the invention independently, and also in combinations other than those shown. Furthermore, the described embodiments can also be supplemented by other features of the invention already described. Additional features and embodiments of the invention can be derived from those skilled in the art in the context of the presented description and claims.

A Play area
B high temperature reduction zone
C cooling area
10 Double shaft furnace unit
11,21 1st shaft, 2nd shaft
12,22 shaft bottom
13,23 Shaft upper part
14,24 Recirculating gas bottom inlet
15,25 Recirculating gas upper inlet
16,26 Oxygenator
17,27 Fuel feeder
18,28 Oxygen fuel injector
19,29 Upper gas outlet
30 connection channels
31 Oxygen fuel injector
32 electric radiant heating tube
33 Electrically heated syngas sprayer and/or syngas plasma torch
41 Upper gas pipeline
42 Gas cleaning device
43 Cleaned upper gas pipeline
51 CO ₂ removal device
52 _CO2 -free gas pipeline
53 _CO2 gas pipeline
54 Export gas pipeline
61 compression unit
62 Recirculating gas pipeline

Claims (17)

Double shaft furnace device 10 for direct reduction of metal iron oxide, wherein the double shaft furnace device 10
- at least one first shaft 11 and a second shaft 21 extending along the vertical direction Z; Each shaft 11; 21 is each shaft 11; a cooling region C at the bottom portions 12 and 22 of 21, a regeneration region A at the upper end of each shaft, and at least one first shaft 11 and a second shaft 21 disposed between the regeneration region A and the cooling region C;
- A connection channel 30 connecting the first shaft 11 and the second shaft 21, where the connection channel 30 extends along the horizontal direction (X), and the connection channel 30 is a high temperature reduction region B of the first shaft 11 and the second shaft 21. A connecting channel 30 disposed at the lower end of and the upper end of the cooling zone C.
Including,
A double shaft furnace device 10 in which at least one injection assembly 31 protrudes laterally from the connecting channel 30.
The dual shaft furnace device of claim 1, wherein the injection assembly consists of or includes at least one of the following: an electrically heated syngas injector, a plasma torch, and an oxyfuel injector.
3. The double shaft furnace according to claim 1 or 2, further comprising an electric heating device 32 consisting of or comprising a plurality of electric radiant heating tubes 32, wherein the electric heating tubes 32 are arranged in the connecting channel 30. Double shaft furnace device 10.
The method according to any one of claims 1 to 3, comprising: each shaft 11; 21 includes at least one bottom recirculation gas inlet 14; A dual shaft furnace device 10 comprising 24 and at least one upper recirculation gas inlet 15, 25.
The method according to any one of claims 1 to 4, wherein each of the first shaft 11 and the second shaft 21 supplies oxygen and fuel to each shaft 11; a plurality of oxyfuel injectors 18 arranged at least partially along the vertical direction Z for injecting into the high temperature reduction zone B of 21; Double shaft furnace device 10 with 28.
6. The method of claim 5, wherein each oxy-fuel injector 18 of the plurality of oxy-fuel injectors; 28 is oxygenator 16; 26 and fuel feeder 17; A double shaft furnace device 10 in fluidic and/or gastight connection with 27.
7. The system of claim 6, wherein the first gas-tight valve is connected to a fuel supply 17; disposed upstream of 27 and downstream of the fuel supply; A second gas-tight valve is connected to the fuel supply 17; disposed upstream of 27 and downstream of the recirculation gas supply; A third gas-tight valve is connected to the oxygen supply 16; disposed upstream of 26 and downstream of the oxygen supply section; and optionally a fourth gas-tight valve disposed upstream of the oxygen supply 16, 26 and downstream of the nitrogen supply, and a fifth gas-tight valve disposed upstream of the oxygen supply 16, 26 and downstream of the recycle gas supply. Double shaft furnace device 10.
The method according to any one of claims 1 to 7, wherein each oxygen supplier 16, 26 is fluidly and/or hermetically connected to the oxygen supplier; and
Each of the fuel supplies 17 and 27 is fluidly and/or hermetically connected to the fuel supply section; and
Each oxygen supply 16, 26 and each fuel supply 17, 27 have at least one recycle gas top inlet 15; 25 or at least a double shaft furnace device 10 fluidly and/or hermetically connected with a recirculating gas pipeline 62 .
9. The method according to any one of claims 1 to 8, wherein each of the first shaft 11 and the second shaft 21 is connected to at least one upper gas pipeline 41 for sending the upper gas to the gas cleaning device 42. having gas outlets 19 and 29; Each gas outlet 19; 29 is each shaft 11; 13 at the top of 21; Placed at 23; and the upper gas pipeline 41 has a gas outlet connected to the gas cleaning device 42.
10. The apparatus of claim 9, wherein the gas cleaning device 42 is a dual shaft furnace device comprising:
a wet scrubber to quench the gas and collect the upper gas dust to remove water; and
Optionally, a dry dust collection unit disposed upstream of the wet scrubber comprising at least one of a dust collector, cyclo, bag filter, and electrostatic dust collector.
The method according to any one of claims 1 to 10, further comprising a CO ₂ removal device 51 for removing carbon dioxide from the gas discharged by the gas cleaning device 42, wherein the removing device 51 is hermetically sealed to the gas cleaning device 42. A double shaft furnace device 10 connected to and disposed downstream thereof.
12. The method of claim 11, wherein the removal device 51 and/or the compression unit 61 disposed downstream of the removal device 51 to compress the recycle gas discharges the recycle gas having a temperature range of 40° C. to 120° C., and transports the recycle gas. Each bottom recirculation gas inlet 14 has a recirculation pipeline 62 for doing so; 24 and/or each upper recirculation gas inlet 15; 25 and/or oxygenator 16; 26 and/or fuel feeder 17; Dual shaft furnace device 10 connected to and/or integrated with 27.
A method of operating a double shaft furnace device 10 according to any one of claims 1 to 12, wherein the method includes
In step 1:
Injecting oxygen and fuel into the high temperature reduction zone B of the first shaft 11;
injecting recirculating gas into the upper end 13 of the first shaft 11;
injecting oxygen and fuel into the connecting channel 30 by at least one injection assembly 31 protruding laterally from the connecting channel 30;
filling the second shaft 21 with metal oxide;
Discharging upper gas from the upper end 23 of the second shaft 21;
discharging the metal product from the bottom 22 of the second shaft 21; and
In the second step:
Injecting oxygen and fuel into the high-temperature combustion area B of the second shaft 21;
injecting recirculating gas into the upper end 23 of the second shaft 21;
injecting oxygen and fuel into the connecting channel 30 by at least one injection assembly 31;
filling the first shaft 11 with metal oxide;
Discharging upper gas from the upper end 13 of the first shaft 11;
discharging the metal product from the bottom 12 of the first shaft 11;
Method of operation of double shaft furnace device 10 comprising.
14. Method according to claim 13, further comprising heating the gas flowing through the connecting channel 30 by means of an electric heating device 32 in the first and second steps.
15. The metal oxide according to claim 13 or 14, wherein the metal oxide has a temperature in the range of -15°C to 40°C, preferably in the temperature range of 15°C to 30°C and most preferably in the temperature range of 25°C; and/or the metal product has a temperature range of 120° C. to 700° C.; The top gas has a temperature in the range of 80°C to 250°C, preferably in the temperature range of 130°C to 170°C, most preferably 150°C.
According to any one of claims 13 to 15,
transferring the upper gas through the upper gas pipeline 41 to a gas cleaning device 42 disposed downstream of the plurality of shafts 11 and 21;
transferring the top gas from the gas cleaning device 42 to a CO ₂ removal device 51 disposed downstream of the gas cleaning device 42; and
Transferring the recirculating gas to the plurality of shafts 11 and 21 through the recirculating pipeline 62.
How to include more.
According to clause 16,
The method further comprising compressing the recycle gas by a compression unit 61 disposed downstream of the CO ₂ remover 51 and upstream of the recycle pipeline 62.