Direct reduction device for producing sponge iron, and method for feeding particles containing iron ore into the reactor of a direct reduction device of this kind
Patent Information
- Application Number
- EP2024701798
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-01-18
- Filing Date
- 2024-01-17
- Publication Date
- 2025-11-26
Smart Images
Figure EP2024050964_25072024_PF_FP_ABST
Abstract
Description
[0001] Direct reduction device for the production of sponge iron and process for
[0002] Feeding iron ore-containing particles into the reactor of such a direct reduction device
[0003] The invention is based on a direct reduction device for producing sponge iron, in particular for an integrated steel production plant, with a reactor and a feed device arranged above the reactor for feeding particles containing iron ore into the reactor via a plurality of feed inlets, wherein a central longitudinal axis of the reactor extends from a top side to a lower end of the reactor and the feed inlets are arranged on the top side of the reactor, wherein at least some of these feed inlets are arranged distributed around the longitudinal axis.
[0004] The invention further relates to a corresponding method for feeding iron ore-containing particles into the reactor of such a direct reduction device, wherein iron ore-containing particles are introduced into the reactor via the feed inlets.
[0005] In direct reduction, solid sponge iron (DRI: Direct Reduced Iron) is produced from iron ore by reducing the oxidation state of Fe. The production of sponge iron in the reactor involves two basic steps: In the first step, the iron ore is reduced to sponge iron in a reduction zone using a suitable hot reducing gas.
[0006] Typically, such a reducing gas essentially comprises H2 (hydrogen) and CO (carbon monoxide) at temperatures ranging from 850 °C to 1100 °C. In a second step, the produced sponge iron is cooled in a cooling zone using a cooling gas to temperatures that are often below 100 °C. The iron ore is fed to the reactor in the form of iron ore-containing particles, such as lump ore, pellets, and / or sintered material particles.
[0007] If angular, especially sharp-edged, particles are introduced into the reactor, they can damage the inside of the reactor's side walls, especially those that form the reactor's shell. For example, lump ore particles can permanently "abrasively" process the lining on the inside of reactor side walls, causing such severe damage that the reactor must be relined. More or less sharp edges on the outer periphery of the particles form the corresponding cutting edges.
[0008] Document EP 2 427 580 B1 describes an integrated steelmaking plant with a direct reduction device for producing sponge iron. The direct reduction device comprises a reactor and a feed device arranged above the reactor for feeding iron ore-containing particles into the reactor via several feed inlets. A central longitudinal axis of the reactor extends from a top side to a bottom end of the reactor, and the feed inlets are arranged on the top side of the reactor distributed around the longitudinal axis. The iron ore is fed into the reactor via the feed inlets as particles in the form of lump ore, pellets, or a mixture thereof.
[0009] It is an object of the invention to provide a direct reduction device for producing sponge iron and a method for feeding iron ore-containing particles into the reactor of such a direct reduction device, in which the risk of damage to side walls of the reactor by the iron ore-containing particles is minimized.
[0010] According to the invention, the object is achieved by the features of the independent claims. Preferred embodiments of the invention are specified in the subclaims, each of which may represent an aspect of the invention individually or in combination.
[0011] In the direct reduction device according to the invention for producing sponge iron, which device has a reactor and a feed device arranged above the reactor for feeding particles containing iron ore into the reactor via a plurality of feed inlets, and in which a central longitudinal axis of the reactor extends from a top side to a lower end of the reactor, the feed inlets are arranged on the top side of the reactor, and at least some of these feed inlets are arranged distributed around the longitudinal axis, it is provided that at least one of the feed inlets is a near-axis feed inlet whose distance from the central longitudinal axis is smaller than the distance of at least one other of the feed inlets. Preferably, said distance from the longitudinal axis is smaller than the respective distance of several other of the feed inlets from the longitudinal axis.The feed inlets to the reactor of the direct reduction device according to the invention are thus arranged such that particles of a particularly angular first type, which pose a greater threat to the side walls of the reactor, can be fed further inside the reactor, while particles of a less angular second type can be fed (also) further outside the reactor. Such a first type (or several such first types) with particularly angular particles can also be referred to as the first type(s) having (or have) a greater abrasive effect, and the corresponding second type(s) having (or have) fewer angular particles compared to the first type(s) can then be referred to as the second type(s) having (or have) a lesser abrasive effect.To enable such use of particles of different types, these particles of different types originate from different sources. These sources can be internal (to the device) or external (to the device).
[0012] According to a preferred embodiment of the direct reduction device according to the invention, it is provided that for supplying the iron ore-containing particles from at least two different sources, separate supply paths are provided, of which at least one supply path is provided for the particles from a first source and leads via the near-axis supply access or - in the case of several such supply paths - leads to one of the near-axis supply accesses and, separately therefrom, at least one supply path is provided for the particles from a second source and leads via the other supply access or - in the case of several such supply paths - leads to one of the other supply accesses.
[0013] With regard to particles of different types, it is particularly provided that the direct reduction device is designed for at least two different types of iron ore-containing particles, wherein for a first type of iron ore-containing particles, there is only at least one feed path to the reactor leading via the at least one near-axis feed access. This feed path, or all corresponding feed paths, is / are maintained by the direct reduction device.
[0014] In other words, the first type of iron ore-containing particles can only be fed via the at least one near-axis feed inlet, while a second type of iron ore-containing particles can (also) be fed to the reactor via the at least one other feed inlet. Accordingly, for a second type of iron ore-containing particles, there is preferably at least one feed path to the reactor leading via the at least one other feed inlet.
[0015] According to a preferred embodiment of the invention, the at least one near-axis feed inlet is circumferentially surrounded, as viewed along the longitudinal axis, by at least two of the other feed inlets. This arrangement allows a particle stream of particles fed into the reactor via the at least one near-axis feed inlet to be shielded from the particle streams of particles fed into the reactor via the other feed inlets, outwardly toward the side walls of the reactor. If the particles fed into the reactor via the at least one near-axis feed inlet are more angular or sharp-edged than those fed into the reactor via the other feed inlets, the risk of damage to said side walls of the reactor is particularly effectively minimized.
[0016] Advantageously, exactly one near-axis feed port is provided, which is arranged as a central feed port on the longitudinal axis of the reactor. This arrangement of the near-axis feed port ensures that the corresponding particle stream is ideally far away from all side walls of the reactor. The distance of this central feed port from the longitudinal axis is logically smaller than the distance of any other feed port from the longitudinal axis. The central feed port is thus circumferentially surrounded by all other feed ports with respect to the longitudinal axis.
[0017] According to a further preferred embodiment of the invention, the feed device comprises storage containers for the different types of iron ore-containing particles. These storage containers are internal (device-internal) sources for the iron ore-containing particles of the different types. In other words, these different types are stored – preferably in pure form – by means of the storage containers.
[0018] According to yet another preferred embodiment of the invention, the
[0019] Feeding device for each of the feed accesses a feed path with a
[0020] Locking device (for introducing the particles (via the respective feed access into the reactor). The respective locking device is in particular of the rotary valve type.
[0021] In particular, it is intended that the lock devices be equipped with gas-tight valves for the gas-tight introduction of the particles into the reactor. This allows the pressure inside the reactor to be adjusted independently of the pressure in the feed device. The use of gas-tight valves for this purpose is well known and has proven effective.
[0022] Advantageously, each of the lock devices comprises a lock chamber and two gas seal valves, with one of the gas seal valves being arranged upstream of the lock chamber in the corresponding feed path, and one of the gas seal valves being arranged downstream of the lock chamber in the corresponding feed path. In a rotary valve, the lock chamber is formed by the cavity between two rotor blades of the rotary valve's rotor.
[0023] The invention further relates to an integrated steel production plant with a direct reduction device as mentioned above and an electrically heated furnace, in particular an arc furnace, connected downstream of the direct reduction device.
[0024] In the method according to the invention for feeding particles containing iron ore into the reactor of an above-mentioned direct reduction device, in which particles containing iron ore are introduced into the reactor via feed inlets and the particles are kept sorted according to types which differ in terms of their abrasive effect with regard to abrasive stress or abrasive wear of reactor walls of the reactor by these particles, wherein the particles of at least a first type which has a higher abrasive effect with regard to the abrasive stress on the reactor walls than at least a second type are introduced into the reactor only via the at least one feed inlet close to the axis.By feeding the particles of the first type into the reactor in such a near-axis manner, the corresponding particle stream is further away from all side walls of the reactor, thereby reducing the risk of damage to these side walls by the said particle stream.
[0025] According to a preferred embodiment of the method according to the invention, the particles of the at least one second type are introduced into the reactor via the at least one other feed inlet, while particles of the first type are also introduced into the reactor in parallel with these particles of the second type(s). This creates a shielding effect.
[0026] Finally, it is advantageously provided that
[0027] (i) the particles of the first type are particles in the form of lump ore and / or sintered material and
[0028] (ii) the particles of the second type of particles are in the form of pellets.
[0029] Lump ore, sinter material and pellets are common iron ore-containing particles used in direct reduction devices.
[0030] The invention will now be explained by way of example with reference to the accompanying drawings using a preferred embodiment, wherein the features presented below may represent an aspect of the invention both individually and in combination. They show:
[0031] Fig. 1 shows a direct reduction device for producing sponge iron according to a preferred embodiment of the invention in a side view and
[0032] Fig. 2 shows a reactor of the direct reduction device in a top view.
[0033] Fig. 1 shows a schematic representation of a direct reduction device 10 for producing sponge iron (DRI: Direct Reduced Iron). This direct reduction device 10 comprises a reactor 12 for the actual reaction and a feed device 14 arranged above the reactor 12 for feeding iron ore in the form of particles 16, 18 into the reactor 12 via several feed inlets 20, 22. The feed inlets 20, 22 are arranged for this purpose on the top side 24 of the reactor 12. The reactor 12 extends vertically along its central longitudinal axis 26 from the top side 24 to its lower end 28. It has a reactor vessel 32 formed by reactor walls 30, in the interior of which - i.e. the interior of the reactor 12 - the corresponding reactions take place.For this purpose, an upper part 34 of reactor 12 contains a reduction zone in which the Fe is reduced from the iron ore. A lower part 36 of reactor 12 contains a cooling zone in which the resulting sponge iron can be cooled. The lower part 36 of reactor 12 is conical in shape and converges at an outlet 38 for the optionally still hot or cold sponge iron.
[0034] The feed device 14 has a plurality of storage containers 40, 42 for the particles 16, 18 (two storage containers in the example shown). These storage containers 40, 42 are intended to hold different types of iron ore-containing particles 16, 18 and can therefore be regarded as sources for iron ore-containing particles 16, 18. In the example shown, there is a first storage container 40 for the particles 16 of two first types of particles (namely, particles in the form of lump ore and sinter material) and a second storage container 42 for the particles 18 of a second type of particles (namely, in the form of pellets). Each of the storage containers 40, 42 is connected to at least one of the feed inlets 20, 22 via a respective feed path 44, 46. The first storage container 40 is connected via the feed path 44 to the near-axis feed access 20 and the second storage container 42 is connected via the feed paths 46 to the other feed accesses 22.Each of the feed paths 44, 46 has a lock device 48 for the gas-tight introduction of the particles 16, 18 into the reactor 12 via the respective feed inlet 20, 22. The lock devices 48, in turn, have gas-tight valves 50 and a lock chamber 52.
[0035] In some embodiments of such a reactor 12, parts of the reactor walls 32, in particular the side walls 32 of the reactor 12, are provided with linings on the side facing the interior of the reactor 12. These linings in particular can be damaged during operation by particles 12 containing iron ore (iron ore particles 12 for short) with sharp edges.
[0036] The following function of the direct reduction device 10 results:
[0037] The iron ore particles 12 are fed to the reactor 12 from the storage containers 40, 42 via the feed paths 44, 46 through the lock devices 48 arranged therein. The particles 12 thus fed sink downward through the reduction zone of the reactor 12 and react at high temperatures (850 °C to 1100 °C) in countercurrent contact with a reducing gas, usually containing CO and / or H2. The reducing gas, or a gas for forming this reducing gas, is introduced into the reactor 12 at an inlet via a line 54, which opens into the lower part of the reduction zone, and is removed from the reactor 12 at an outlet in the upper part of the reduction zone via another line 56. However, a major portion of this removed gas retains its reducing potential and is then returned to the reactor 12 at the inlet via line 54.
[0038] The cooling zone is located in the lower part 36 of the reactor 12. This part 36 is preferably conically shaped and converges to the outlet 38, through which the already reduced ore, i.e., the sponge iron or DRI, is discharged hot or cold. In the cooling zone in the lower part 36 of the reactor 12, a cooling gas stream (containing any non-oxidizing, inert, or reducing gas, such as natural gas) is normally circulated countercurrently to extract heat from the hot sponge iron / DRI. This cooling gas is introduced through a cooling gas line 58 into a lower section of the conically shaped lower part 36 of the reactor 12 and removed in a heated state from an upper section of the lower part 36 of the reactor 12 through another cooling gas line 60 and then returned to line 58 in a closed circuit. In this resulting cooling circuit 62, the hot gas is cleaned and cooled before being reintroduced into the reactor 12.For this purpose, the cooling circuit 62 comprises a cooling tower 64 and a compressor 66.
[0039] When it is desired to discharge the sponge iron / DRI at high temperature, the cooling circuit 62 is shut down and the DRI does not undergo any type of active cooling before being discharged from the reactor 12 via the outlet 38.
[0040] Regarding the feeding of the iron ore particles 16, 18 via the feed inlets 20, 22 into the reactor 12, the following procedure is provided:
[0041] The particles 16, 18 are sorted by type and stored in the storage containers 40, 42. The different types of particles 16, 18 differ in their abrasive effect with regard to abrasive wear on the reactor walls 30 of the reactor 12, which is particularly important for the side walls. The particles 16 stored (bunkered) in the first storage container 40 are of at least one first type, which, with regard to abrasive wear on the reactor walls 30, has a higher abrasive wear potential than the particles 18 of the at least one second type stored (bunkered) in the second storage container 42. The particles 16 of the first type are particles in the form of lump ore and / or sintered material, and the particles 18 of the second type are particles in the form of pellets. The pellets 18 are much less sharp-edged than the lump ore and sinter material particles 16.Therefore, the lump ore and sinter material particles 16, i.e. the particles of the first type, are only introduced into the reactor 12 via the near-axis feed inlet 20, while the pellets 18, i.e. the particles 18 of the second type, are introduced into the reactor 12 via the other feed inlets 22, if particles 16 of the first type(s) are also introduced into the reactor 12 in parallel to these pellets / particles 18 of the second type.
[0042] Fig. 2 shows the reactor 12 of the direct reduction device 10 in a top view. In this example, the near-axis feed inlet 20 is arranged as a central feed inlet 20 on the longitudinal axis 26 of the reactor 12, as Fig. 2 clearly shows. Via this central arrangement of the near-axis feed inlet 20, the corresponding particle stream of the particles 16 of the first type is approximately equally distant from all reactor walls 30 of the reactor 12, which are designed as side walls. The distance of this central feed inlet 20 from the longitudinal axis 26 is logically smaller than the distance of any other of the feed inlets 22 from the longitudinal axis 26. The central feed inlet 20 is thus circumferentially surrounded by all other feed inlets 22 with respect to the longitudinal axis 26.
[0043] This arrangement shields the particle stream of particles 16 fed into reactor 12 via the near-axis or central feed inlet 20 (in this example, particles 16 of the first type: lump ore and sinter material) from the particle streams of particles 18 fed into reactor 12 via the other feed inlets 22 (in this example, particles 18 of the second type: pellets) circumferentially outward in the direction of the side walls 30 of reactor 12. If the particles 16 fed into reactor 12 via the at least one near-axis feed inlet 20 are more angular or sharp-edged than those fed into reactor 12 via the other feed inlets 22, the risk of damage to said side walls 30 of the reactor is particularly effectively minimized.
[0044] Reference symbol
[0045] 10 Direct reduction device
[0046] 12 reactors
[0047] 14 Feeding device
[0048] 16 particles (first type)
[0049] 18 particles (second type)
[0050] 20 Feed access
[0051] 22 Feed access
[0052] 24 Top
[0053] 26 Longitudinal axis (reactor)
[0054] 28 lower end
[0055] 30 reactor wall
[0056] 32 reactor vessels
[0057] 34 upper part
[0058] 36 lower part
[0059] 38 Outlet
[0060] 40 storage containers
[0061] 42 storage containers
[0062] 44 Feed path
[0063] 46 Feed path
[0064] 48 Lock system
[0065] 50 Gas seal valve
[0066] 52 Lock room
[0067] 54 Line (reducing gas)
[0068] 56 additional line (reducing gas)
[0069] 58 Cooling gas line
[0070] 60 additional cooling gas lines
[0071] 62 Cooling circuit
[0072] 64 Cooling tower
[0073] 66 Compressor
Claims
Patent claims 1. Direct reduction device (10) for producing sponge iron, in particular for an integrated steel production plant, comprising a reactor (12) and a feed device (14) arranged above the reactor (12) for feeding particles (16, 18) containing iron ore into the reactor (12) via a plurality of feed inlets (20, 22), wherein a central longitudinal axis (26) of the reactor (12) extends from a top side (24) to a bottom end (28) of the reactor (12) and the feed inlets (20, 22) are arranged on the top side (24) of the reactor (12), wherein at least some of these feed inlets (22) are arranged distributed around the longitudinal axis (26), characterized in that at least one of the feed inlets (20) is a near-axis feed inlet (20) whose distance from the longitudinal axis (26) is less than the distance of at least one other of the feed inlets (22).
2. Direct reduction device according to claim 1, wherein separate feed paths (44, 46) are provided for feeding the iron ore-containing particles (16, 18) from at least two different sources, of which at least one feed path (44) is provided for the particles (16) from a first source and leads via the near-axis feed inlet (20) or - in the case of several such feed paths (44) - leads to one of the near-axis feed inlets (20) and, separate therefrom, at least one feed path (46) is provided for the particles (18) from a second source and leads via the other feed inlet (22) or - in the case of several such feed paths (46) - leads to one of the other feed inlets (22).
3. Direct reduction device according to claim 1 or 2, wherein the direct reduction device (10) is provided for at least two different types of iron ore-containing particles (16, 18), wherein for a first type of iron ore-containing particles (16) only the at least one feed path (44) leading via the at least one near-axis feed access (20) to the reactor (12) is provided.
4. Direct reduction device according to claim 3, wherein for a second type of iron ore-containing particles (16) the at least one feed path (46) leading via the at least one other feed access (22) to the reactor (12) is provided.
5. Direct reduction device according to one of claims 1 to 4, wherein the at least one near-axis feed access (20) is circumferentially surrounded by at least two of the other feed accesses (22) with respect to the longitudinal axis (26).
6. Direct reduction device according to one of claims 1 to 5, wherein exactly one near-axis feed access (20) is provided, which is arranged as a central feed access on the longitudinal axis (26).
7. Direct reduction device according to one of claims 1 to 6, wherein the feed device has storage containers (40, 42) for the different types of iron ore-containing particles (16, 18).
8. Direct reduction device according to one of claims 1 to 7, wherein the feed device (14) has for each of the feed inlets (20, 22) a feed path (44, 46) with a lock device (48) for introducing the particles (16, 18) via the respective feed inlet (20, 22) into the reactor (12).
9. Direct reduction device according to claim 8, wherein the lock devices (48) have gas sealing valves (50) for gas-tight introduction of the particles (20, 22) into the reactor (12).
10. Direct reduction device according to claim 9, wherein each of the lock devices (48) has a lock chamber (52) and two gas sealing valves (50), wherein one of the gas sealing valves (50) is arranged in the corresponding feed path (44, 46) before and one of the gas sealing valves (50) is arranged in the corresponding feed path (44, 46) after the lock chamber (52).
11. A method for feeding iron ore-containing particles into the reactor (12) of a direct reduction device (10) according to one of claims 1 to 7, in which iron ore-containing particles (16, 18) are introduced into the reactor (12) via feed inlets (20, 22), wherein the particles (16, 18) are kept sorted according to types which differ in terms of their abrasive effect with regard to abrasive wear of reactor walls (30) of the reactor (12) by these particles (16, 18), wherein the particles (16) are of at least a first type which, with regard to the abrasive Wear of the reactor walls has a higher abrasive effect than at least a second type, are introduced into the reactor (12) only via the at least one near-axis feed inlet (20).
12. The method according to claim 11, wherein the particles (18) of the at least one second Type are introduced into the reactor (12) via the at least one other feed inlet (22), if particles (16) of the first type(s) are also introduced into the reactor (12) parallel to these particles (18) of the second type(s).
13. The method according to claim 11 or 12, wherein the particles (16) of the first type are in the form of lump ore and / or sintered material and the particles (18) of the second type are in the form of pellets.