CA2388847A1 - Process for the direct reduction of iron-oxide-containing material - Google Patents
Process for the direct reduction of iron-oxide-containing material Download PDFInfo
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- CA2388847A1 CA2388847A1 CA002388847A CA2388847A CA2388847A1 CA 2388847 A1 CA2388847 A1 CA 2388847A1 CA 002388847 A CA002388847 A CA 002388847A CA 2388847 A CA2388847 A CA 2388847A CA 2388847 A1 CA2388847 A1 CA 2388847A1
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- gas
- reducing gas
- fluidized
- pressure
- used reducing
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/0033—In fluidised bed furnaces or apparatus containing a dispersion of the material
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/10—Reduction of greenhouse gas [GHG] emissions
- Y02P10/122—Reduction of greenhouse gas [GHG] emissions by capturing or storing CO2
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/10—Reduction of greenhouse gas [GHG] emissions
- Y02P10/134—Reduction of greenhouse gas [GHG] emissions by avoiding CO2, e.g. using hydrogen
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/10—Reduction of greenhouse gas [GHG] emissions
- Y02P10/143—Reduction of greenhouse gas [GHG] emissions of methane [CH4]
Abstract
The invention relates to a method for direct reduction of materials containing iron oxide using a reduction gas containing CO and H2 in at least one fluidized bed reduction zone, whereby the used reduction gas containing CO2 coming out of the at least one fluidized bed reduction zone is recirculated and a fresh reduction gas is produced by CO2 reforming of the used reduction gas and a gas containing methane, especially natural gas. CO2 reforming and direct reduction are carried out at a pressure of at least 4 bar overpressure in order to substantially prevent carbon formation and deposition and in order to keep the size of the reactor receiving the reduction zone small, whereby the reduction zone is exposed to an amount of reduction gas complying with metallurgical requirements.
Description
Process for the direct reduction of iron-oxide-containing material The invention relates to a process for the direct reduction of iron-oxide-containing material by means of a CO- and H2-containing reducing gas in at least one fluidized-bed reduction zone, COz-containing, used reducing gas which emerges from the at least one fluidized-bed reduction zone being recirculated and fresh reducing gas being produced by COz reforming of the used reducing gas and of a methane-containing gas, in particular natural gas, and to an installation for carrying out the process.
Processes in which CO- and HZ-containing reducing gas is produced by what is known as steam reforming of methane-containing gas and steam, the steam reforming being carried out at high pressures and high temperatures and hydrocarbons and steam being converted into CO and HZ by means of nickel catalysts in accordance with the following reaction:
Steam reforming reaction: CH4 + HZO -~ CO + 3 Hz are known from the prior art, for example from US-A-5,082,251.
In a CO shift reaction which follows the steam reforming, the CO which is formed during the reforming is then converted into C02 and Hz in accordance with the following equation:
CO shift reaction: CO + H20 -~ COz + Hz The C02 usually then has to be removed from the reformed gas, and the gas from which the COz has been removed has to be heated.
By contrast, in the case of COZ reforming, which is known, for example, from DE-A 196 37 180 and DE-A-195 17 766, not only steam is converted, but also C02, in accordance with the following equation:
COz reforming reaction: CH4 + C02 ~ 2 CO + 2 HZ
The advantage of the C02 reforming is that there is no need for any removal of COZ or for any subsequent heating of the reducing gas to the desired reduction temperature.
DE-A-196 37 180 has disclosed a process in which fine iron oxide particles are reduced by means of a CO- and HZ-containing reducing gas in a spouted bed and a bubbling bed which is connected downstream of the spouted bed, the reducing gas being produced from the used CO-, COZ- and H20-containing reducing gas by means of COZ reforming. The reforming and the direct reduction take place at low pressures of from 1.6 to 2.4 bar.
DE-A-195 17 766 has. disclosed a process in which fine iron oxide particles are reduced in a plurality of circulating fluidized beds, which are connected in series, likewise by means of a CO- and H2-containing reducing gas, fresh reducing gas likewise, as in DE-A-196 37 180, being produced from the used CO-, COz-and H20-containing reducing gas by COZ reforming.
US-A-4,348,226 has disclosed a process in which off-gas from a reducing shaft furnace is mixed with natural gas, and the gas mixture is reformed in a heated reformer, and in which further natural gas is admixed with the reformed gas, and the gas mixture which is then formed is subjected, in an unheated reactor, to an endothermic reforming reaction, fresh reducing gas being formed for the reduction shaft furnace. The sensible heat of the gas which has been reformed in the heated reformer is utilized in the second, endothermic reforming reaction, and the desired reducing-gas temperature is established.
It is known that COZ reforming takes place more successfully at lower pressures and that the reformer tubes can be designed to be thinner and therefore less expensive at low pressures.
The invention is based on the object of providing a process for the direct reduction of iron-oxide-containing material, in which CO- and HZ-containing reducing gas can be produced by COZ
reforming of a methane-containing gas, in particular natural gas, and used reducing gas, in which, however, the drawbacks of the known processes, which use a COz reformer, such as the formation of carbon, deposits, large reactor diameters, etc., are to be avoided. The overall size of a reactor which accommodates the reduction zone is to be kept small, but at the same time a quantity of reducing gas which satisfies the metallurgical requirements is to pass through the reduction zone.
According to the invention, this object is achieved by the fact that the C02 reforming and the direct reduction are carried out at high pressure, preferably at a pressure of at least 4 bar superatmospheric pressure (5 bar absolute), in particular at a pressure of approximately 7 bar superatmospheric pressure. The pressure range which is appropriate in a technical context in a process of this type is 6 to 8 bar superatmospheric pressure; the upper pressure limit is 15 bar superatmospheric pressure.
Surprisingly, it has been found that, in this way, many factors which have a disruptive effect on the reduction process, such as the formation of carbon and deposits, can be avoided in the fluidized-bed reduction zone.
Processes in which CO- and HZ-containing reducing gas is produced by what is known as steam reforming of methane-containing gas and steam, the steam reforming being carried out at high pressures and high temperatures and hydrocarbons and steam being converted into CO and HZ by means of nickel catalysts in accordance with the following reaction:
Steam reforming reaction: CH4 + HZO -~ CO + 3 Hz are known from the prior art, for example from US-A-5,082,251.
In a CO shift reaction which follows the steam reforming, the CO which is formed during the reforming is then converted into C02 and Hz in accordance with the following equation:
CO shift reaction: CO + H20 -~ COz + Hz The C02 usually then has to be removed from the reformed gas, and the gas from which the COz has been removed has to be heated.
By contrast, in the case of COZ reforming, which is known, for example, from DE-A 196 37 180 and DE-A-195 17 766, not only steam is converted, but also C02, in accordance with the following equation:
COz reforming reaction: CH4 + C02 ~ 2 CO + 2 HZ
The advantage of the C02 reforming is that there is no need for any removal of COZ or for any subsequent heating of the reducing gas to the desired reduction temperature.
DE-A-196 37 180 has disclosed a process in which fine iron oxide particles are reduced by means of a CO- and HZ-containing reducing gas in a spouted bed and a bubbling bed which is connected downstream of the spouted bed, the reducing gas being produced from the used CO-, COZ- and H20-containing reducing gas by means of COZ reforming. The reforming and the direct reduction take place at low pressures of from 1.6 to 2.4 bar.
DE-A-195 17 766 has. disclosed a process in which fine iron oxide particles are reduced in a plurality of circulating fluidized beds, which are connected in series, likewise by means of a CO- and H2-containing reducing gas, fresh reducing gas likewise, as in DE-A-196 37 180, being produced from the used CO-, COz-and H20-containing reducing gas by COZ reforming.
US-A-4,348,226 has disclosed a process in which off-gas from a reducing shaft furnace is mixed with natural gas, and the gas mixture is reformed in a heated reformer, and in which further natural gas is admixed with the reformed gas, and the gas mixture which is then formed is subjected, in an unheated reactor, to an endothermic reforming reaction, fresh reducing gas being formed for the reduction shaft furnace. The sensible heat of the gas which has been reformed in the heated reformer is utilized in the second, endothermic reforming reaction, and the desired reducing-gas temperature is established.
It is known that COZ reforming takes place more successfully at lower pressures and that the reformer tubes can be designed to be thinner and therefore less expensive at low pressures.
The invention is based on the object of providing a process for the direct reduction of iron-oxide-containing material, in which CO- and HZ-containing reducing gas can be produced by COZ
reforming of a methane-containing gas, in particular natural gas, and used reducing gas, in which, however, the drawbacks of the known processes, which use a COz reformer, such as the formation of carbon, deposits, large reactor diameters, etc., are to be avoided. The overall size of a reactor which accommodates the reduction zone is to be kept small, but at the same time a quantity of reducing gas which satisfies the metallurgical requirements is to pass through the reduction zone.
According to the invention, this object is achieved by the fact that the C02 reforming and the direct reduction are carried out at high pressure, preferably at a pressure of at least 4 bar superatmospheric pressure (5 bar absolute), in particular at a pressure of approximately 7 bar superatmospheric pressure. The pressure range which is appropriate in a technical context in a process of this type is 6 to 8 bar superatmospheric pressure; the upper pressure limit is 15 bar superatmospheric pressure.
Surprisingly, it has been found that, in this way, many factors which have a disruptive effect on the reduction process, such as the formation of carbon and deposits, can be avoided in the fluidized-bed reduction zone.
Furthermore, a sufficiently high supply of gas per unit volume of the reduction reactor to satisfy the metallurgical requirements is provided for the reduction, so that the reactors which accommodate the ' 5 fluidized-bed reduction zones can be of smaller dimensions. Nevertheless, a sufficient gas throughput is still ensured. Moreover, the reduction potential of the reducing gas is higher.
Furthermore, iron sponge which is produced during the direct reduction of iron-oxide-containing material can advantageously be fed by pneumatic conveying by means of the reducing gas to be briquetted, so that a briquetting device which is used for the briquetting can be arranged next to a direct reduction device which is used for the direct reduction, with the result that the overall size of the entire installation for carrying out the process according to the invention can be kept small.
The advantage of the process according to the invention is that the C02 which is present in the used reducing gas does not have to be removed, but rather is used directly for the production of fresh reducing gas.
Compared to known direct reduction processes, for example that described in US-A-5,082,251, which was mentioned in the introduction, in which the reducing gas is produced by steam reforming, without the steam reformer being connected into the reducing-gas circuit, connecting the C02 reformer into the reducing-gas circuit means that a lower specific flow of reducing gas is required for the direct reduction; the specific flow of reducing gas is understood to mean the flow rate of freshly supplied reducing gas based on the material which is to be reduced.
It is preferable for the used reducing gas to be subjected to a CO shift reaction at least in part prior to the reforming. In this way, the CO is converted into C02 and H2 by means of steam in accordance with the following equation:
CO shift reaction: CO + H20 -> COZ + H2.
' 5 The CO content of the gas supplied to the reformer is advantageously minimized in the process, and the CO/COZ
ratio is set.
On account of a high CO content in the reducing gas, in particular if the gas which is to be reformed already contains CO, problems caused by metal dusting, which is understood as meaning destruction of the metallic parts of the installation by CO, may occur in metallic parts of the installation. If the gas which is to be reformed, should it contain CO, is subjected to a CO
shift reaction, metal dusting can be substantially avoided.
If the H20 content of the COz- and CO-containing gas is not high enough for a CO shift reaction, steam is advantageously added to the CO shift reaction.
On account of the once-through operation, which is understood as meaning the fact that the reformer is connected directly into the reducing-gas circuit, without any devices which have a significant influence on the temperature and composition of the reducing gas being provided between the reformer and a reduction reactor which accommodates the fluidized-bed reduction zone, there are fewer possible ways of adjusting the reducing-gas quality than if the reformer is connected outside the reducing-gas circuit. According to WO-A-96 00304, which, like US-A-5,082,251, has disclosed a direct reduction process using a steam reformer connected outside the reducing-gas circuit, there are, for example, possible ways of setting the reducing-gas quality by changing the way in which the reformer operates, by changing the extent to which COz is scrubbed out of the reformed gas and/or used reducing gas, etc.
With the aid of the CO shift reaction which is provided according to a preferred variant of the process according to the invention, it is possible even when using once-through operation for the gas ratios required for the reforming and the direct reduction to be set as required, i.e. for the CO/HZ ratio to be varied or the CO content to be reduced according to the specific requirements.
According to a further preferred embodiment, the used reducing gas is compressed prior to the reforming, preferably to a pressure of approximately 8 bar superatmospheric pressure.
It is preferable for the waste heat of the reforming to be used to preheat air, H20, natural gas, etc.
The used reducing gas is advantageously compressed prior to the CO shift reaction, preferably to a pressure of approximately 8 bar superatmospheric pressure.
The used reducing gas is expediently heated prior to the reforming and prior to the optional CO shift reaction.
The present invention also relates to an installation for carrying out the process according to the invention, having at least one fluidized-bed reactor, which accommodates a fluidized-bed reduction zone, a feed line for feeding a CO- and H2-containing reducing gas to the fluidized-bed reactor and a gas discharge line for discharging used reducing gas, which leads from the fluidized-bed reactor to a C02 reformer in order to produce the CO- and HZ-containing reducing gas from a methane-containing gas, in particular natural - 7 _ gas, and the used reducing gas, the C02 reformer being line-connected to the fluidized-bed reactor via the feed line.
According to the invention, this installation is characterized in that there is a compression device for compressing the gas which is supplied to the fluidized-bed reactor to a high pressure, preferably to a pressure of at least 5 bar superatmospheric pressure, in particular to a pressure of approximately 8 bar superatmospheric pressure, upstream of the COZ
reformer.
It is preferable for a CO shift reactor to be provided upstream of the C02 reformer for used reducing gas. The feed line for steam may in this case open out upstream of the CO shift reactor into a feed line for the COz-and, if appropriate, CO-containing gas and/or into the CO shift reactor itself.
According to an even more preferred embodiment, the compression device for compressing the used reducing gas is provided upstream of the CO shift reactor.
In the installation according to the invention, it is preferable for at least three, and in particular preferably four, fluidized-bed reactors which are connected in series to be provided.
To accurately set the chemical composition of the reducing gas for optimum efficiency of the COZ
reformer, the CO shift reactor can expediently be bypassed by means of a bypass line for the used reducing gas.
It is advantageous for a line which supplies a CH4-containing gas, in particular natural gas, to open out into the gas line which supplies used reducing gas to the COz reformer.
The installation according to the invention is expediently characterized by a heating device for the cleaned and compressed used reducing gas.
' 5 The invention is explained in more detail below with reference to the drawing, in which Figures 1 and 2 in each case illustrate a preferred embodiment of the invention, identical components in each case being provided with identical reference symbols.
Figure 1 shows four fluidized-bed reactors 1 to 4 which are connected in series and each accommodate a steady-state fluidized bed, iron-oxide-containing material, such as fine ore, being supplied via an ore feed line 5 to the uppermost fluidized-bed reactor 4, in which heating to reduction temperature and, if appropriate, preliminary reduction take place, and then being passed from fluidized-bed reactor 4 to fluidized-bed reactors 3, 2 and 1 via delivery lines 6a to 6c. The fully reduced material (iron sponge) is fed, via a discharge line 7 and a riser 8, which is understood as meaning a substantially vertical section of pipe which has a refractory lining and is used to convey the iron sponge pneumatically upwards by means of the reducing gas, to a storage hopper 9 and, from there, to a briquetting device 10, in which the iron sponge is hot-briquetted. If appropriate, the reduced material is protected from reoxidation during the briquetting by an inert-gas system (not shown) or is fed to an electric arc furnace situated below.
The reducing gas which is used to convey the iron sponge through the riser 8 is extracted and expanded via a line 11 and is then fed for further use, for example for heating purposes (not illustrated). The use of a riser 8 has the advantage that the briquetting device 10 can be arranged next to the reduction device formed from the fluidized-bed reactors 1 to 4, with the result that the overall height of the entire installation can be lowered. A further possibility (not illustrated) of conveying the iron sponge into the storage hopper 9 without using a riser 8 consists in the lowermost fluidized-bed reactor 1 being arranged at a height which is such that the iron sponge can flow into the storage hopper 9, which is arranged at a lower level, by means of the force of gravity; in this case, however, the drawback of a greater overall height of the entire installation has to be accepted.
Before the iron-oxide-containing material is introduced into the first fluidized-bed reactor 4, as seen in the direction of flow of the material, it is subjected to a preparation treatment, such as a drying treatment (not illustrated in more detail).
Reducing gas is fed to the lowermost fluidized-bed reactor 1 via a feed line 12, is carried from fluidized-bed reactor 1 to fluidized-bed reactors 2, 3 and 4 via lines 13a to 13c in countercurrent to the flow of the material which is to be reduced and is extracted via a gas discharge line 14 as used reducing gas. By way of example, the reducing gas flows into the lowermost fluidized-bed reactor 1 at a temperature of approximately 800°C and a pressure of approximately 8 bar absolute and leaves the uppermost fluidized-bed reactor 4 as used reducing gas at a temperature of approximately 550°C and a pressure of approximately 6 bar absolute.
The used reducing gas is cooled and scrubbed in a cooler/cleaner 15, where dust and steam are removed.
The cooled and cleaned gas, which according to the embodiments illustrated is passed through a circuit, is then fed to a compressor 17 via a line 16. In the compressor 17, the used reducing gas is compressed, for example to a pressure of approximately 8 bar. Following the compressor 17 there is a heating device 18, which is used to heat the used reducing gas, which has been greatly cooled during the cleaning by the ' cooler/cleaner 15, back up to a temperature which it needs for a CO shift reaction. The used reducing gas which has been heated in this way is then fed via the line 16a to a CO shift reactor 19, in which the CO
which is present in the used reducing gas is partly converted, by means of steam, to CO2 and H2. In the exemplary embodiment illustrated in Fig. 1, steam is fed via a feed line 20 into the line 16a by means of which the used reducing gas is carried to the CO shift reactor 19. However, the steam may also, by way of example, be fed directly into the CO shift reactor 19.
In the CO shift reactor 19, the CO which is present in the used reducing gas is (partially) converted into COZ
and Hz by means of steam.
The provision of the CO shift reactor 19 on the one hand advantageously increases the COZ content of the gas which is fed to the COZ reformer, which promotes the reformer reaction, and, on the other hand, reduces the CO content, with the result that metal dusting, i.e. the destruction of metallic parts of the installation by CO, is substantially avoided. In addition, the CO shift reactor 19 results in more possible ways of setting the desired reducing-gas quality. The gas ratios required for the reforming and the direct reduction can be set according to the particular requirements, i.e. the CO/HZ ratio can be varied and/or the CO content can be reduced according to requirements.
The CO shift reactor 19 can be bypassed by means of a bypass line 21, resulting in a wide range of possibilities for setting the desired reducing-gas quality, for example as a result of a partial quantity of the used reducing gas being fed directly to the COz reformer 22 without being passed through the CO shift reactor 19.
In the C02 reformer 22, the gas which is supplied via the line 16b, if appropriate prior to heating, is reacted together with methane-containing gas, in the example illustrated natural gas, which is supplied via a line 23, so that CO and H2 are formed.
The reformed gas leaves the COz reformer for example at a temperature of approximately 930°C. To allow it to be used as fresh reducing gas, the reformed gas still has to be heated to the desired reducing-gas temperature. In the exemplary embodiment illustrated, the reformed gas which is extracted from the C02 reformer 22 via a line 12 is in part guided via a cooler 24 and the remaining part is guided via a line 12a which bypasses the cooler and has a valve 25, during which process a reducing-gas temperature of approximately 800°C is established.
The COZ reformer 22 is heated by burning natural gas, which is supplied via a line 26, with an oxygen-containing gas, such as air, which gas is supplied via a line 27. Part of the used, heated reducing gas can be branched off via a line 28 and can likewise be burned with an oxygen-containing gas, such as air, in order to heat the CO2 reformer 22. The combustion off-gases which are formed in the process are extracted from the COZ reformer 22 via a line 29.
The high pressure in the reducing-gas circuit, for example approximately 7 to 8 bar absolute upstream of the COz reformer 22 and approximately 6 to 7 bar before the gas is introduced into the lowermost fluidized-bed reactor 1, allows all the internal fittings (lines, fluidized-bed reactors) to be of correspondingly small dimensions. Furthermore, the formation of carbon and deposits is substantially avoided in all components.
Finally, a riser 8 may advantageously be used to convey , - 12 -the reduced material to the briquetting device 10, as has already been explained in more detail above.
According to the embodiment illustrated in Fig. 2, the used reducing gas, after it has been heated in the heating device 18, is fed directly to the COZ reformer 22, with the result that the installation is simplified, but there is not such a wide range of possibilities for influencing the composition of the reducing gas leaving the COz reformer as there are in the embodiment illustrated in Fig. 1.
Chemical compositions of the gases, temperatures and pressures in accordance~with the exemplary embodiment illustrated in Fig. 1 are explained in more detail in the example which follows (pressure details are in bar absolute).
A) Flow of ore Ore introduced into the fluidized-bed reactor 4 via the ore feed line 5:
Temperature: approx. 50°C, ore weight based on the product approx. 1.44.
Composition: hematite (Fe203) with a pure iron content of approx. 67%, grain size up to at most 12.5 mm.
Ore discharged from the fluidized-bed reactor 1 via the discharge line 7:
Temperature: approx. 800°C, reduced ore Composition: total iron content approx. 93% (Fe), metallization 92%
C = 1.5 - 2.5%
Grain size: up to at most 6.3 mm The reduced ore is conveyed for briquetting 10 via the riser 8.
B) Gas flow Gas introduced into the fluidized-bed reactor 1 via the line 13:
Pressure: approx. 7 bar superatmospheric pressure Temperature: approx. 800°C
Reducing-gas composition: CO: 21.7%
CO2: 3.2%
H2: 57.2%
H20 : 5 . 6 %
CH4: 6.2%
N2: 6.1%
Gas discharge of the used reducing gas from the fluidized-bed reactor 4 via the gas discharge line 14:
Pressure: approx. 5 bar superatmospheric pressure Temperature: approx. 550°C
Gas composition: CO: 15.4%
C02: 8.8%
H2: 46.5%
CH4: 4.4%
H20: 18.3%
N2: 6.5%
Dust content in the gas: approx. 27 kg/t of product, with 9.5 g/m3n.
Deposition of the dust through reducing-gas scrubber 15 (also referred to as cooler/cleaner):
Used reducing gas after scrubber 15:
Pressure: approx. 4 bar superatmospheric pressure Temperature: approx. 40°C
Dust content: 27.3 g/t of product with approx. 10 mg/m3n.
Used reducing gas after the compressor 16:
Pressure increase to approx. 8 bar superatmospheric pressure ' CA 02388847 2002-04-23 Temperature: approx. 100°C
' Used reducing gas after the heating device 18:
Pressure: approx. 7.8 bar superatmospheric pressure Temperature: approx. 350°C
Input into the CO shift reactor 19:
Pressure: approx. 7.8 bar superatmospheric pressure Temperature: approx. 350°C
Gas composition: C0: 14.0%
CO2 : 8 . 0 %
H2: 42.4%
H20: 26.6%
CH4: 4.0%
N2: 5.2%
Used reducing gas after the CO shift reactor 19:
Pressure: approx. 7.5 bar superatmospheric pressure Temperature: approx. 450°C
Entry of the used reducing gas into the COz reformer 22 (after CH4 has been admixed):
Pressure: approx. 7.5 bar superatmospheric pressure Temperature: approx. 450°C
Gas composition: CO: 4.4%
COz: 13.6%
H2: 43.9%
Hz0 : 14 . 9 CH4: 17.5%
N2: 5.8%
Reducing-gas discharge from COZ reformer 22 via the line 12:
Pressure: approx. 7 bar superatmospheric pressure Temperature: approx. 930°C
Gas composition: CO: 22.6%
CO2: 3.3%
H2: 59.5%
Furthermore, iron sponge which is produced during the direct reduction of iron-oxide-containing material can advantageously be fed by pneumatic conveying by means of the reducing gas to be briquetted, so that a briquetting device which is used for the briquetting can be arranged next to a direct reduction device which is used for the direct reduction, with the result that the overall size of the entire installation for carrying out the process according to the invention can be kept small.
The advantage of the process according to the invention is that the C02 which is present in the used reducing gas does not have to be removed, but rather is used directly for the production of fresh reducing gas.
Compared to known direct reduction processes, for example that described in US-A-5,082,251, which was mentioned in the introduction, in which the reducing gas is produced by steam reforming, without the steam reformer being connected into the reducing-gas circuit, connecting the C02 reformer into the reducing-gas circuit means that a lower specific flow of reducing gas is required for the direct reduction; the specific flow of reducing gas is understood to mean the flow rate of freshly supplied reducing gas based on the material which is to be reduced.
It is preferable for the used reducing gas to be subjected to a CO shift reaction at least in part prior to the reforming. In this way, the CO is converted into C02 and H2 by means of steam in accordance with the following equation:
CO shift reaction: CO + H20 -> COZ + H2.
' 5 The CO content of the gas supplied to the reformer is advantageously minimized in the process, and the CO/COZ
ratio is set.
On account of a high CO content in the reducing gas, in particular if the gas which is to be reformed already contains CO, problems caused by metal dusting, which is understood as meaning destruction of the metallic parts of the installation by CO, may occur in metallic parts of the installation. If the gas which is to be reformed, should it contain CO, is subjected to a CO
shift reaction, metal dusting can be substantially avoided.
If the H20 content of the COz- and CO-containing gas is not high enough for a CO shift reaction, steam is advantageously added to the CO shift reaction.
On account of the once-through operation, which is understood as meaning the fact that the reformer is connected directly into the reducing-gas circuit, without any devices which have a significant influence on the temperature and composition of the reducing gas being provided between the reformer and a reduction reactor which accommodates the fluidized-bed reduction zone, there are fewer possible ways of adjusting the reducing-gas quality than if the reformer is connected outside the reducing-gas circuit. According to WO-A-96 00304, which, like US-A-5,082,251, has disclosed a direct reduction process using a steam reformer connected outside the reducing-gas circuit, there are, for example, possible ways of setting the reducing-gas quality by changing the way in which the reformer operates, by changing the extent to which COz is scrubbed out of the reformed gas and/or used reducing gas, etc.
With the aid of the CO shift reaction which is provided according to a preferred variant of the process according to the invention, it is possible even when using once-through operation for the gas ratios required for the reforming and the direct reduction to be set as required, i.e. for the CO/HZ ratio to be varied or the CO content to be reduced according to the specific requirements.
According to a further preferred embodiment, the used reducing gas is compressed prior to the reforming, preferably to a pressure of approximately 8 bar superatmospheric pressure.
It is preferable for the waste heat of the reforming to be used to preheat air, H20, natural gas, etc.
The used reducing gas is advantageously compressed prior to the CO shift reaction, preferably to a pressure of approximately 8 bar superatmospheric pressure.
The used reducing gas is expediently heated prior to the reforming and prior to the optional CO shift reaction.
The present invention also relates to an installation for carrying out the process according to the invention, having at least one fluidized-bed reactor, which accommodates a fluidized-bed reduction zone, a feed line for feeding a CO- and H2-containing reducing gas to the fluidized-bed reactor and a gas discharge line for discharging used reducing gas, which leads from the fluidized-bed reactor to a C02 reformer in order to produce the CO- and HZ-containing reducing gas from a methane-containing gas, in particular natural - 7 _ gas, and the used reducing gas, the C02 reformer being line-connected to the fluidized-bed reactor via the feed line.
According to the invention, this installation is characterized in that there is a compression device for compressing the gas which is supplied to the fluidized-bed reactor to a high pressure, preferably to a pressure of at least 5 bar superatmospheric pressure, in particular to a pressure of approximately 8 bar superatmospheric pressure, upstream of the COZ
reformer.
It is preferable for a CO shift reactor to be provided upstream of the C02 reformer for used reducing gas. The feed line for steam may in this case open out upstream of the CO shift reactor into a feed line for the COz-and, if appropriate, CO-containing gas and/or into the CO shift reactor itself.
According to an even more preferred embodiment, the compression device for compressing the used reducing gas is provided upstream of the CO shift reactor.
In the installation according to the invention, it is preferable for at least three, and in particular preferably four, fluidized-bed reactors which are connected in series to be provided.
To accurately set the chemical composition of the reducing gas for optimum efficiency of the COZ
reformer, the CO shift reactor can expediently be bypassed by means of a bypass line for the used reducing gas.
It is advantageous for a line which supplies a CH4-containing gas, in particular natural gas, to open out into the gas line which supplies used reducing gas to the COz reformer.
The installation according to the invention is expediently characterized by a heating device for the cleaned and compressed used reducing gas.
' 5 The invention is explained in more detail below with reference to the drawing, in which Figures 1 and 2 in each case illustrate a preferred embodiment of the invention, identical components in each case being provided with identical reference symbols.
Figure 1 shows four fluidized-bed reactors 1 to 4 which are connected in series and each accommodate a steady-state fluidized bed, iron-oxide-containing material, such as fine ore, being supplied via an ore feed line 5 to the uppermost fluidized-bed reactor 4, in which heating to reduction temperature and, if appropriate, preliminary reduction take place, and then being passed from fluidized-bed reactor 4 to fluidized-bed reactors 3, 2 and 1 via delivery lines 6a to 6c. The fully reduced material (iron sponge) is fed, via a discharge line 7 and a riser 8, which is understood as meaning a substantially vertical section of pipe which has a refractory lining and is used to convey the iron sponge pneumatically upwards by means of the reducing gas, to a storage hopper 9 and, from there, to a briquetting device 10, in which the iron sponge is hot-briquetted. If appropriate, the reduced material is protected from reoxidation during the briquetting by an inert-gas system (not shown) or is fed to an electric arc furnace situated below.
The reducing gas which is used to convey the iron sponge through the riser 8 is extracted and expanded via a line 11 and is then fed for further use, for example for heating purposes (not illustrated). The use of a riser 8 has the advantage that the briquetting device 10 can be arranged next to the reduction device formed from the fluidized-bed reactors 1 to 4, with the result that the overall height of the entire installation can be lowered. A further possibility (not illustrated) of conveying the iron sponge into the storage hopper 9 without using a riser 8 consists in the lowermost fluidized-bed reactor 1 being arranged at a height which is such that the iron sponge can flow into the storage hopper 9, which is arranged at a lower level, by means of the force of gravity; in this case, however, the drawback of a greater overall height of the entire installation has to be accepted.
Before the iron-oxide-containing material is introduced into the first fluidized-bed reactor 4, as seen in the direction of flow of the material, it is subjected to a preparation treatment, such as a drying treatment (not illustrated in more detail).
Reducing gas is fed to the lowermost fluidized-bed reactor 1 via a feed line 12, is carried from fluidized-bed reactor 1 to fluidized-bed reactors 2, 3 and 4 via lines 13a to 13c in countercurrent to the flow of the material which is to be reduced and is extracted via a gas discharge line 14 as used reducing gas. By way of example, the reducing gas flows into the lowermost fluidized-bed reactor 1 at a temperature of approximately 800°C and a pressure of approximately 8 bar absolute and leaves the uppermost fluidized-bed reactor 4 as used reducing gas at a temperature of approximately 550°C and a pressure of approximately 6 bar absolute.
The used reducing gas is cooled and scrubbed in a cooler/cleaner 15, where dust and steam are removed.
The cooled and cleaned gas, which according to the embodiments illustrated is passed through a circuit, is then fed to a compressor 17 via a line 16. In the compressor 17, the used reducing gas is compressed, for example to a pressure of approximately 8 bar. Following the compressor 17 there is a heating device 18, which is used to heat the used reducing gas, which has been greatly cooled during the cleaning by the ' cooler/cleaner 15, back up to a temperature which it needs for a CO shift reaction. The used reducing gas which has been heated in this way is then fed via the line 16a to a CO shift reactor 19, in which the CO
which is present in the used reducing gas is partly converted, by means of steam, to CO2 and H2. In the exemplary embodiment illustrated in Fig. 1, steam is fed via a feed line 20 into the line 16a by means of which the used reducing gas is carried to the CO shift reactor 19. However, the steam may also, by way of example, be fed directly into the CO shift reactor 19.
In the CO shift reactor 19, the CO which is present in the used reducing gas is (partially) converted into COZ
and Hz by means of steam.
The provision of the CO shift reactor 19 on the one hand advantageously increases the COZ content of the gas which is fed to the COZ reformer, which promotes the reformer reaction, and, on the other hand, reduces the CO content, with the result that metal dusting, i.e. the destruction of metallic parts of the installation by CO, is substantially avoided. In addition, the CO shift reactor 19 results in more possible ways of setting the desired reducing-gas quality. The gas ratios required for the reforming and the direct reduction can be set according to the particular requirements, i.e. the CO/HZ ratio can be varied and/or the CO content can be reduced according to requirements.
The CO shift reactor 19 can be bypassed by means of a bypass line 21, resulting in a wide range of possibilities for setting the desired reducing-gas quality, for example as a result of a partial quantity of the used reducing gas being fed directly to the COz reformer 22 without being passed through the CO shift reactor 19.
In the C02 reformer 22, the gas which is supplied via the line 16b, if appropriate prior to heating, is reacted together with methane-containing gas, in the example illustrated natural gas, which is supplied via a line 23, so that CO and H2 are formed.
The reformed gas leaves the COz reformer for example at a temperature of approximately 930°C. To allow it to be used as fresh reducing gas, the reformed gas still has to be heated to the desired reducing-gas temperature. In the exemplary embodiment illustrated, the reformed gas which is extracted from the C02 reformer 22 via a line 12 is in part guided via a cooler 24 and the remaining part is guided via a line 12a which bypasses the cooler and has a valve 25, during which process a reducing-gas temperature of approximately 800°C is established.
The COZ reformer 22 is heated by burning natural gas, which is supplied via a line 26, with an oxygen-containing gas, such as air, which gas is supplied via a line 27. Part of the used, heated reducing gas can be branched off via a line 28 and can likewise be burned with an oxygen-containing gas, such as air, in order to heat the CO2 reformer 22. The combustion off-gases which are formed in the process are extracted from the COZ reformer 22 via a line 29.
The high pressure in the reducing-gas circuit, for example approximately 7 to 8 bar absolute upstream of the COz reformer 22 and approximately 6 to 7 bar before the gas is introduced into the lowermost fluidized-bed reactor 1, allows all the internal fittings (lines, fluidized-bed reactors) to be of correspondingly small dimensions. Furthermore, the formation of carbon and deposits is substantially avoided in all components.
Finally, a riser 8 may advantageously be used to convey , - 12 -the reduced material to the briquetting device 10, as has already been explained in more detail above.
According to the embodiment illustrated in Fig. 2, the used reducing gas, after it has been heated in the heating device 18, is fed directly to the COZ reformer 22, with the result that the installation is simplified, but there is not such a wide range of possibilities for influencing the composition of the reducing gas leaving the COz reformer as there are in the embodiment illustrated in Fig. 1.
Chemical compositions of the gases, temperatures and pressures in accordance~with the exemplary embodiment illustrated in Fig. 1 are explained in more detail in the example which follows (pressure details are in bar absolute).
A) Flow of ore Ore introduced into the fluidized-bed reactor 4 via the ore feed line 5:
Temperature: approx. 50°C, ore weight based on the product approx. 1.44.
Composition: hematite (Fe203) with a pure iron content of approx. 67%, grain size up to at most 12.5 mm.
Ore discharged from the fluidized-bed reactor 1 via the discharge line 7:
Temperature: approx. 800°C, reduced ore Composition: total iron content approx. 93% (Fe), metallization 92%
C = 1.5 - 2.5%
Grain size: up to at most 6.3 mm The reduced ore is conveyed for briquetting 10 via the riser 8.
B) Gas flow Gas introduced into the fluidized-bed reactor 1 via the line 13:
Pressure: approx. 7 bar superatmospheric pressure Temperature: approx. 800°C
Reducing-gas composition: CO: 21.7%
CO2: 3.2%
H2: 57.2%
H20 : 5 . 6 %
CH4: 6.2%
N2: 6.1%
Gas discharge of the used reducing gas from the fluidized-bed reactor 4 via the gas discharge line 14:
Pressure: approx. 5 bar superatmospheric pressure Temperature: approx. 550°C
Gas composition: CO: 15.4%
C02: 8.8%
H2: 46.5%
CH4: 4.4%
H20: 18.3%
N2: 6.5%
Dust content in the gas: approx. 27 kg/t of product, with 9.5 g/m3n.
Deposition of the dust through reducing-gas scrubber 15 (also referred to as cooler/cleaner):
Used reducing gas after scrubber 15:
Pressure: approx. 4 bar superatmospheric pressure Temperature: approx. 40°C
Dust content: 27.3 g/t of product with approx. 10 mg/m3n.
Used reducing gas after the compressor 16:
Pressure increase to approx. 8 bar superatmospheric pressure ' CA 02388847 2002-04-23 Temperature: approx. 100°C
' Used reducing gas after the heating device 18:
Pressure: approx. 7.8 bar superatmospheric pressure Temperature: approx. 350°C
Input into the CO shift reactor 19:
Pressure: approx. 7.8 bar superatmospheric pressure Temperature: approx. 350°C
Gas composition: C0: 14.0%
CO2 : 8 . 0 %
H2: 42.4%
H20: 26.6%
CH4: 4.0%
N2: 5.2%
Used reducing gas after the CO shift reactor 19:
Pressure: approx. 7.5 bar superatmospheric pressure Temperature: approx. 450°C
Entry of the used reducing gas into the COz reformer 22 (after CH4 has been admixed):
Pressure: approx. 7.5 bar superatmospheric pressure Temperature: approx. 450°C
Gas composition: CO: 4.4%
COz: 13.6%
H2: 43.9%
Hz0 : 14 . 9 CH4: 17.5%
N2: 5.8%
Reducing-gas discharge from COZ reformer 22 via the line 12:
Pressure: approx. 7 bar superatmospheric pressure Temperature: approx. 930°C
Gas composition: CO: 22.6%
CO2: 3.3%
H2: 59.5%
Claims (14)
1. Process for the direct reduction of iron-oxide-containing material by means of a CO- and H2-containing reducing gas in at least one fluidized-bed reduction zone, CO2-containing, used reducing gas which emerges from the at least one fluidized-bed reduction zone being recirculated and fresh reducing gas being produced by CO2 reforming of the used reducing gas and of a methane-containing gas, in particular natural gas, characterized in that the CO2 reforming and the direct reduction are carried out at high pressure, preferably at a pressure of at least 4 bar superatmospheric pressure (5 bar absolute), in particular at a pressure of approximately 7 bar superatmospheric pressure.
2. Process according to Claim 1, characterized in that the used reducing gas is subjected to a CO shift reaction at least in part prior to the reforming.
3. Process according to Claim 2, characterized in that steam is added to the used reducing gas before and/or during the CO shift reaction.
4. Process according to one of Claims 1 to 3, characterized in that the used reducing gas is compressed prior to the reforming, preferably to a pressure of approximately 8 bar superatmospheric pressure.
5. Process according to one or more of Claims 2 to 4, characterized in that the used reducing gas is compressed prior to the CO shift reaction, preferably to a pressure of approximately 8 bar superatmospheric pressure.
6. Process according to one or more of Claims 1 to 5, characterized in that the used reducing gas is heated prior to the reforming and prior to the optional CO
shift reaction.
shift reaction.
7. Installation for carrying out the process according to one of Claims 1 to 6, having at least one fluidized-bed reactor (1 to 4), which accommodates a fluidized-bed reduction zone, a feed line (12, 13) for feeding a CO- and H2-containing reducing gas to the fluidized-bed reactor (1 to 4) and a gas discharge line (14, 16, 16a, 16b) for discharging used reducing gas, which leads from the fluidized-bed reactor (1 to 4) to a CO2 reformer (22) in order to produce the CO- and H2-containing reducing gas from a methane-containing gas, in particular natural gas, and the used reducing gas, the CO2 reformer (22) being line-connected to the fluidized-bed reactor (1 to 4) via the feed line (12, 13), characterized in that there is a compression device (17) for compressing the gas which is supplied to the fluidized-bed reactor (1 to 4) to a high pressure, preferably to a pressure of at least 5 bar superatmospheric pressure, in particular to a pressure of approximately 8 bar superatmospheric pressure, upstream of the CO2 reformer (22).
8. Installation according to Claim 7, characterized in that a CO shift reactor (19) is provided upstream of the CO2 reformer (22) for used reducing gas.
9. Installation according to Claim 8, characterized in that a feed line (20) for steam opens out into the CO shift reactor (19) or into the gas line (16a) which carries used reducing gas and opens out into the CO
shift reactor (19).
shift reactor (19).
10. Installation according to one of Claims 7 to 9, characterized in that the compression device (17) for compressing the used reducing gas is provided upstream of the CO shift reactor (19).
11. Installation according to one or more of Claims 7 to 10, characterized in that at least three, preferably four, fluidized-bed reactors (1 to 4) which are connected in series are provided.
12. Installation according to one or more of Claims 8 to 11, characterized in that the CO shift reactor (19) can be bypassed by means of a bypass line (21) for the used reducing gas.
13. Installation according to one or more of Claims 7 to 12, characterized in that a line (23) which supplies a CH4-containing gas, in particular natural gas, opens out into the gas line (16b) which supplies used reducing gas to the CO2 reformer (22).
14. Installation according to one or more of Claims 7 to 13, characterized by a heating device (19) for the cleaned and compressed used reducing gas.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT0181699A AT407879B (en) | 1999-10-28 | 1999-10-28 | METHOD FOR DIRECTLY REDUCING IRON OXIDE MATERIALS |
| ATA1816/99 | 1999-10-28 | ||
| PCT/EP2000/009726 WO2001031069A1 (en) | 1999-10-28 | 2000-10-05 | Method for direct reduction of materials containing iron oxide |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2388847A1 true CA2388847A1 (en) | 2001-05-03 |
Family
ID=3521619
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002388847A Abandoned CA2388847A1 (en) | 1999-10-28 | 2000-10-05 | Process for the direct reduction of iron-oxide-containing material |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP1224335A1 (en) |
| JP (1) | JP2003512532A (en) |
| KR (1) | KR20020045617A (en) |
| AT (1) | AT407879B (en) |
| AU (1) | AU1021301A (en) |
| CA (1) | CA2388847A1 (en) |
| MX (1) | MXPA02004227A (en) |
| WO (1) | WO2001031069A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7591874B2 (en) | 2003-10-03 | 2009-09-22 | Corus Technology Bv | Method and apparatus for reducing metal-oxygen compounds |
| US10351423B2 (en) * | 2015-05-29 | 2019-07-16 | Eduardo Luigi SZEGO | Processes for synthesis of reducing gaseous mixtures starting from hydrocarbon streams and carbon dioxide |
| US11685961B2 (en) | 2019-03-15 | 2023-06-27 | Primetals Technologies Austria GmbH | Method for direct reduction in a fluidized bed |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002000944A1 (en) * | 2000-06-28 | 2002-01-03 | Voest-Alpine Industrieanlagenbau Gmbh & Co | Method and device for directly reducing particulate oxide-containing ores |
| BR112013007729B1 (en) * | 2010-11-05 | 2018-05-08 | Metaltek Int Inc | reformer pipe apparatus, and method for providing a reformer pipe apparatus |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3305312A (en) * | 1963-03-12 | 1967-02-21 | Exxon Research Engineering Co | Synthesis process |
| JPS523359B1 (en) * | 1971-07-08 | 1977-01-27 | ||
| US4265868A (en) * | 1978-02-08 | 1981-05-05 | Koppers Company, Inc. | Production of carbon monoxide by the gasification of carbonaceous materials |
| JPS5550411A (en) * | 1978-10-03 | 1980-04-12 | Ishikawajima Harima Heavy Ind Co Ltd | Direct iron manufacturing method |
| DE2911692A1 (en) * | 1979-03-24 | 1980-10-02 | Metallgesellschaft Ag | METHOD FOR PRODUCING REDUCING GAS FROM SOLID FUELS |
| JPS57185914A (en) * | 1981-05-13 | 1982-11-16 | Kawasaki Steel Corp | Fluidized reduction method for iron ore by circulation of heat medium particle and reducing gas as well as coal |
| US5082251A (en) * | 1990-03-30 | 1992-01-21 | Fior De Venezuela | Plant and process for fluidized bed reduction of ore |
| US5674308A (en) * | 1994-08-12 | 1997-10-07 | Midrex International B.V. Rotterdam, Zurich Branch | Spouted bed circulating fluidized bed direct reduction system and method |
| US6149859A (en) * | 1997-11-03 | 2000-11-21 | Texaco Inc. | Gasification plant for direct reduction reactors |
-
1999
- 1999-10-28 AT AT0181699A patent/AT407879B/en active
-
2000
- 2000-10-05 KR KR1020027005406A patent/KR20020045617A/en not_active Application Discontinuation
- 2000-10-05 MX MXPA02004227A patent/MXPA02004227A/en not_active Application Discontinuation
- 2000-10-05 JP JP2001533202A patent/JP2003512532A/en not_active Withdrawn
- 2000-10-05 CA CA002388847A patent/CA2388847A1/en not_active Abandoned
- 2000-10-05 AU AU10213/01A patent/AU1021301A/en not_active Abandoned
- 2000-10-05 WO PCT/EP2000/009726 patent/WO2001031069A1/en not_active Application Discontinuation
- 2000-10-05 EP EP00971317A patent/EP1224335A1/en not_active Withdrawn
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7591874B2 (en) | 2003-10-03 | 2009-09-22 | Corus Technology Bv | Method and apparatus for reducing metal-oxygen compounds |
| US10351423B2 (en) * | 2015-05-29 | 2019-07-16 | Eduardo Luigi SZEGO | Processes for synthesis of reducing gaseous mixtures starting from hydrocarbon streams and carbon dioxide |
| US11685961B2 (en) | 2019-03-15 | 2023-06-27 | Primetals Technologies Austria GmbH | Method for direct reduction in a fluidized bed |
Also Published As
| Publication number | Publication date |
|---|---|
| AU1021301A (en) | 2001-05-08 |
| WO2001031069A1 (en) | 2001-05-03 |
| JP2003512532A (en) | 2003-04-02 |
| ATA181699A (en) | 2000-11-15 |
| AT407879B (en) | 2001-07-25 |
| EP1224335A1 (en) | 2002-07-24 |
| MXPA02004227A (en) | 2002-12-16 |
| KR20020045617A (en) | 2002-06-19 |
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