KR101321928B1 - Molten iron manufacturing apparatus and molten iron manufacturing method using the same - Google Patents

Abstract

The present invention relates to a molten iron manufacturing apparatus and a method for manufacturing the same, comprising: a raw material pretreatment system for sorting and pretreating iron ore raw materials to be suitable for reduction; And a first rising pipe to which the pretreated iron ore raw material is transferred from the raw material pretreatment facility, and a second rising pipe connected to the first rising pipe, wherein the transferred iron ore raw material is pre-reduced by reducing gas. Pre-reduction reactor; A reduction reactor for reducing the partial reduced iron transferred from the pre-reduction reactor; A molten reduction reactor producing molten iron by melting and reducing the partially reduced iron obtained from the reduction reactor using a reducing gas; A steel off-product by-product pretreatment system for mixing and reforming carbon dioxide generated in a steelmaking by-product gas or iron ore reduction process and supplying the generated reducing gas to the melt reduction reactor or the pre-reduction reactor; And an iron ore reduction process facility that supplies carbon dioxide generated in the iron ore reduction process.

Description

A molten iron manufacturing apparatus and a molten iron manufacturing method using the same {APPARATUS FOR MANUFACTURING MOLTEN IRONS AND METHOD FOR MANUFACTURING MOLTEN IRONS USING THE SAME}

The present invention relates to a molten iron manufacturing apparatus and a method for manufacturing molten iron using the same. More particularly, molten iron is reduced by molten reduction while reducing iron ore using gas generated by reforming by-product gas generated in a steelmaking process. The present invention relates to a production apparatus and a method for manufacturing molten iron using the same.

Conventional iron ore reduction technology using a fluidized bed reduction reactor is a methane gas-based reduced iron production technology that supplies hydrogen by methane-steam reforming in the 1950s, mainly 90% hydrogen reducing agent, iron ore fluidization under the reaction temperature of below 600 ℃ and above 5 atm The technique for producing reduced iron by the disclosed in US Patent No. 2,821,471 or 3,022,156, based on the reducing agent gas generated by the gasification of coal (C) mainly reduced iron ore at a reaction temperature of 600 ℃ or more The technique for producing this is disclosed in US Pat. No. 3,246,978.

The two methods differ depending on the type of reducing agent used, and the reaction conditions of reduced iron production, such as change in physical and chemical properties of iron ore, fluidization properties, and sticking, are solved. While the patent uses a bubbling fluidized bed, a technique (US Pat. No. 5,431,711) for reducing iron ore in the form of a circulating fluidized bed has been developed to reduce iron ore in the form of fine powder discarded at an ironworks.

The continuous development of the technology has developed into commercial technologies such as FINEX, which produces reduced iron by reducing ferrous ore of several millimeters or less in a fluidized bed reactor, and reducing agent remaining after CO2 removal of by-product gas to increase the efficiency of molten iron production. Techniques using gas (US Patent No. 5,846,268) have also been introduced. However, methane gas or coal (C) based reduced iron production process was mainly limited to the use of high-grade iron ore, there was a limit to the reduction of a variety of fine iron ore that is not currently used, including magnetite present in the fine powder of several hundred microns or less.

In addition, new technologies are needed to overcome the emission limits of large amounts of carbon dioxide in the coal (C) -based steelmaking process, increase steel production, and respond to environmental problems.

Embodiments of the present invention are to provide an apparatus for producing molten iron by reducing the iron ore raw material by selecting hydrogen and carbon monoxide using the by-product gas generated in the iron making process and a method for producing molten iron using the same.

In one or more embodiments of the present invention, a raw material pretreatment system for sorting and pretreating iron ore raw materials suitable for reduction; And a first rising pipe to which the pretreated iron ore raw material is transferred from the raw material pretreatment facility, and a second rising pipe connected to the first rising pipe, wherein the transferred iron ore raw material is pre-reduced by reducing gas. Pre-reduction reactor; A reduction reactor for reducing the partial reduced iron transferred from the pre-reduction reactor; A molten reduction reactor producing molten iron by melting and reducing the partially reduced iron obtained from the reduction reactor using a reducing gas; A steel off-product by-product pretreatment system for mixing and reforming carbon dioxide generated in a steelmaking by-product gas or iron ore reduction process and supplying the generated reducing gas to the melt reduction reactor or the pre-reduction reactor; And an iron ore reduction process facility for supplying carbon dioxide generated in the iron ore reduction process may be provided.

In one or more embodiments of the present invention, the iron ore reduction process equipment, the second pre-reduction reactor for pre-reducing the iron ore raw material by the reducing gas supplied from the reduction reactor; A second raw material pretreatment facility for supplying the iron ore raw material that has been screened and pretreated to be suitable for the second pre-reduction reactor by the reducing gas supplied from the second pre-reduction reactor; And a carbon dioxide line separating carbon dioxide from a reducing gas line connected to the raw material pretreatment facility and supplying carbon dioxide to the steelmaking by-product gas pretreatment facility. . ≪ / RTI >

In one or more embodiments of the present invention, the steelmaking by-product gas pretreatment apparatus may include: an iron-making by-product gas separator for separating hydrogen from steelmaking by-product gas and supplying the separated hydrogen to the second riser; A first heater for supplying heat to the iron by-product gas from which the hydrogen is separated by heat exchange with a circulating gas circulating through the raw material pretreatment facility; A first reforming reactor for generating hydrogen and carbon as the iron-based by-product gas from which the hydrogen supplemented by the first heater is separated, and supplying the generated hydrogen to the first riser; And carbon dioxide generated from the first reforming reactor connected to the first reforming reactor, carbon dioxide generated by the combustion of the gas used in the first heater, and carbon dioxide generated in the iron ore reduction process facility to produce carbon monoxide. And the produced carbon monoxide may include a second reforming reactor for supplying to the melt reduction reactor.

One or more embodiments of the present invention may further include a second heater for supplying heat to the second reforming reactor.

In one or more embodiments of the present invention, the steelmaking by-product gas pretreatment apparatus includes: an iron-making by-product gas separator for separating hydrogen and supplying the separated hydrogen to the second riser; A first heater for replenishing heat by circulating gas circulating the hydrogen by-product by-product separated from the hydrogen through the raw material pretreatment facility; And carbon dioxide generated by the combustion of the gas used in the first heater and carbon dioxide generated in the iron ore reduction process facility to produce a reducing gas including hydrogen and carbon monoxide and the produced reducing gas is the melt reduction. It may include a third reforming reactor for supplying the reactor.

In one or more embodiments of the present invention, the first riser is operated at 800 ° C. or higher, and the second riser is operated at 350 to 650 ° C.

In one or more embodiments of the present invention, a first heat exchanger is installed between the steelmaking by-product gas separation device and the second riser to form a heat exchange with hydrogen discharged from the first riser and the second riser. Compensating for the heat of the reducing gas supplied to the second riser, the hydrogen gas discharged from the second riser is installed on the second ore conduit connecting the first and the second riser. A second heat exchanger for supplying the first rising pipe after heat exchange with a partial reduced iron flowing through a second ore conduit may be installed, and the raw material pretreatment facility receives heat from a reducing gas line for supplying reducing gas from the reduction reactor. It is characterized by.

In one or more embodiments of the present invention, the hydrocarbon processing apparatus for supplying high heat and reducing gas is installed in the melt reduction reactor, and the oxygen reduction line for supplying pure oxygen may be installed in the melt reduction reactor. The hydrocarbon treatment device is characterized in that the device for burning coal pulverized coal, coke and briquette form.

In one or more embodiments of the present invention may further include a carbon dioxide separator connected to a reducing gas line to separate carbon dioxide from the reducing gas, the reducing gas connected to the carbon dioxide separator and passed through the carbon dioxide separator. It may further include a carbon dioxide line for supplying a reduced gas line and the separated carbon dioxide to the steelmaking by-product pre-treatment facility to supply to the reduction reactor, the carbon dioxide storage is installed on the carbon dioxide line to store the separated carbon dioxide The apparatus may further include.

In one or more embodiments of the present invention, a steam-gas reforming reactor connected to a second raw material pretreatment plant for reforming the gas discharged through the second raw material pretreatment facility to generate steam; And a hydrogen separation device connected to the steam-gas reforming reactor to separate the generated steam and carbon dioxide. As shown in FIG.

In one or more embodiments of the present invention, a carbon dioxide line connected to a hydrogen separation device to supply the separated carbon dioxide to a steelmaking by-product pretreatment facility, and the hydrogen separation device to connect the separated hydrogen to the reduction reactor and the first reactor. It may further include a hydrogen line for supplying the riser.

In one or more embodiments of the present invention, a fourth heat exchanger may be formed on the hydrogen line to supplement the heat source with hydrogen in the hydrogen line by heat exchange with gas supplied from the melt reduction reactor to the reduction reactor. It may further include a carbon dioxide storage device is installed on the carbon dioxide line to store the separated carbon dioxide, the raw material pretreatment equipment from the hydrogen line and the reduction reactor to supplement the heat amount to the hydrogen passed through the fourth heat exchanger The third heater may be installed on the reducing gas line connected to the.

In one or more embodiments of the present invention, a raw material pretreatment step of pretreating the iron ore raw material to be suitable for reduction; Transferring the pretreated raw material to a pre-reduction reactor including a first riser and a second riser to pre-reduce by reducing gas; Reducing the partially reduced iron that was pre-reduced and transferred to the reduction reactor; A melt reduction step of producing molten iron by melting and reducing the partially reduced iron obtained from the reduction reactor using a reducing gas; A steel off-product by-product pretreatment step of mixing and modifying carbon dioxide generated in a steelmaking by-product gas and an iron ore reduction process and supplying the generated reducing gas to the melt reduction step or the pre-reduction step; And an iron ore reduction step of supplying carbon dioxide generated in the iron ore reduction step; A molten iron manufacturing method including a may be provided.

In one or more embodiments of the present invention, the steelmaking by-product gas pretreatment step may include: separating hydrogen from the steelmaking by-product gas and supplying the separated hydrogen to the first riser; The iron by-product gas from which the hydrogen is separated is heated by heat exchange with a circulating gas circulated through the raw material pretreatment facility and supplied to the first reforming reactor to produce carbon and hydrogen to supply the produced hydrogen to the pre-reduction reactor. Making; Supplying the produced carbon, carbon dioxide generated by the heating, and carbon dioxide generated in the iron ore reduction process step into a second reforming reactor to produce carbon monoxide and supplying the produced carbon monoxide to the melt reduction reactor; . ≪ / RTI >

In one or more embodiments of the present invention, the steelmaking by-product gas pretreatment step may include: separating hydrogen from the steelmaking by-product gas and supplying the separated hydrogen to the pre-reduction reactor; Heating the iron by-product gas from which the hydrogen is separated by heat exchange with a circulating gas circulating through the raw material pretreatment facility; And supplying the heated hydrogen by-product off-gas separated into the third reforming reactor to produce a reducing gas including carbon and hydrogen, and supplying the produced reducing gas to the melt reduction reactor. . ≪ / RTI >

In one or more embodiments of the present invention, the unreacted carbon dioxide may be further recovered in the reducing gas production step and recycled back to the third reforming reactor.

In one or more embodiments of the present invention, the raw material pretreatment step is a step of performing a preliminary heating by deforming the iron ore raw material by receiving a heat amount by the reducing gas discharged from the reduction reactor. In addition, the iron ore raw material is hematite, magnetite, moisture-containing iron ore or steelmaking process dust (dust), characterized in that the fine form of any one or more.

In one or more embodiments of the present invention, the first riser is operated at 800 ° C. or higher, and the second riser is operated at a range of 350 ° C. to 650 ° C., and the hydrogen separated from the steelmaking by-product gas. Is supplied to the second riser by heat exchange with hydrogen discharged from the first riser and the second riser, and on the second ore conduit connecting the first and the second riser. It is characterized in that the hydrogen gas discharged from the second riser is heat-exchanged with the partial reduced iron flowing through the second ore conduit to increase the temperature and then supply the hydrogen gas to the first riser.

In one or more embodiments of the present invention, the melt reduction step may further include receiving high heat and reducing gas by a hydrocarbon processing apparatus connected to the melt reduction reactor, and receiving pure oxygen through an oxygen line. have.

In one or more embodiments of the present invention, the iron ore reduction step may include: pre-reducing iron ore raw materials by reducing gas supplied from the reduction reactor to the second pre-reduction reactor; Supplying iron ore raw material pre-treated to be suitable for the second pre-reduction reactor by the reducing gas supplied from the second pre-reduction reactor to the second raw material pretreatment facility to the second pre-reduction reactor; And separating carbon dioxide from the reducing gas discharged from the second preliminary reduction reactor and supplying the carbon dioxide to the iron by-product by-product pretreatment step. . ≪ / RTI >

In one or more embodiments of the present invention, the separation of carbon dioxide is performed by a carbon dioxide separation unit or a hydrogen separation unit connected to the second raw material pretreatment facility, and the steam-gas reforming reactor is disposed at the front end of the hydrogen separation unit. Is installed to generate water vapor in the reducing gas introduced from the second raw material pretreatment facility, and the hydrogen separated from the hydrogen separation device is exchanged with the reducing gas supplied from the melt reduction reactor to the reduction reactor. It is heated and supplied to the first riser.

Embodiments of the present invention are to reform the iron by-product gas including carbon dioxide to produce a hydrogen-rich reducing agent gas, and by using hydrogen and carbon monoxide in the reducing agent to selectively reduce iron ore by reducing the iron iron ore of the hematite and magnetite system Can be prepared.

In addition, carbon dioxide is recovered and reformed and recycled using a steelmaking process gas, thereby reducing carbon dioxide and securing a large amount of hydrogen reducing agent, thereby reducing the low-grade iron ore.

1 is a schematic diagram of a molten iron manufacturing apparatus according to an embodiment of the present invention.
2 is a schematic view of a molten iron manufacturing apparatus according to a first embodiment of the present invention.
3 is a schematic diagram of a molten iron manufacturing apparatus according to a second embodiment of the present invention.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, it is to be understood that the present invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. It is intended that the disclosure of the present invention be limited only by the terms of the appended claims. Like reference numerals refer to like elements throughout the specification.

1 is a schematic view of a molten iron manufacturing apparatus according to an embodiment of the present invention, referring to Figure 1, the molten iron manufacturing apparatus of the embodiment according to the present invention to produce molten iron by using the iron and steel by-products efficiently It comprises a raw material pretreatment facility 10, steelmaking by-product gas pretreatment facility 20, pre-reduction / reduction reactor 30 and the melt reduction reactor (40). The molten iron manufacturing apparatus according to the embodiment of the present invention may be modified with the type of raw materials used or installed with additional apparatus.

The raw material pretreatment system 10 is supplied to the raw material pretreatment system 10 through the iron ore raw material line 5 to the low-grade ore, which is generally in the form of fine particles of several millimeters or less, to be deformed or controlled to reduce the It is a device that performs preheating.

The raw material pretreatment facility 10 is to vary depending on the form of the reduction and melting reactor of iron ore, when the pre-reduction / reduction reactor 30 is a fixed bed form, the iron ore particles present in the fine form is transformed into a pellet (pellet) form, etc. It is advantageous. Particularly, fine iron ore of several hundred microns or less including magnetite which is not suitable for blast furnace type reactor, as well as fine iron ore of several tens of microns or less discharged in dust form during the steelmaking process, is transformed into pellet form during raw material pretreatment. Can be. They may be mixed with coal or present in a charcoal form with a binder.

On the other hand, when the pre-reduction / reduction reactor 30 is in the form of a fluidized bed, the iron ore in the form of fine particles, which exist from thousands of microns to several microns, is a bubble fluidized bed, a circulating fluidized bed, or a riser according to its shape and physicochemical properties. It can be suitably selected and pretreated to suit various fluidized bed reactors, such as rotary fluidized bed, drum or spray form.

Iron ore in the form of fine powder in the embodiment according to the present invention includes hematite and magnetite, which can not be used directly in the form of blast furnace, low iron ore containing a lot of moisture, dust ore in the form of dust (dust) discharged as a by-product of the steelmaking process. The finely divided iron ore selected according to the pre-reduction / reduction reactor 30 shape may be heated to an appropriate temperature or morphologically modified by physicochemical methods. In particular, iron ore containing a lot of moisture, such as limonite can be dried or pre-heated, iron ore with high impurities or low iron content such as taconite may be subjected to a raw material pretreatment process such as crushing or beneficiation in advance.

In addition, the steel by-product by-product pretreatment unit 20 recovers carbon dioxide from the gas discharged from the iron ore reduction process through a carbon dioxide line 37, and then, the steel by-product gas such as coke oven exhaust gas is a steel by-product gas line (6) When supplied through the feed is mixed together, reformed, sorted and separated to supply the reducing gas to the melt reduction reactor 40 through the reducing gas line 70 as appropriate.

The reformed reducing gas includes hydrogen and carbon monoxide as main components, and is appropriately distributed and supplied selectively according to the type of iron ore to reduce the hydrogen and carbon monoxide in the pre-reduction / reduction reactor 30 and the melt reduction reactor 40. It can effectively enhance the reducing ability of. To this end, the iron and gas by-product pretreatment system 20 properly supplies a reducing gas suitable for reducing the lower iron ore using a carbon dioxide recovery and reuse technology as well as a heat recovery and heat supply system of the reactor.

As described above, in the embodiment of the present invention, carbon dioxide may be reduced by recovering and recycling carbon dioxide generated during the steelmaking process.

1, in the embodiment according to the present invention, the iron ore raw material pretreated in the raw material pretreatment facility 10 is introduced into the pre-reduction / reduction reactor 30 through the ore conduit 52, the pre-reduction / reduction reactor At 30, the iron ore raw material is pre-reduced and reduced and introduced into the molten reduction reactor 40 through the partial reduced iron transfer pipe (54).

In this case, the preliminary reduction / reduction reactor 30 reduces the reducing gas generated from the molten reduction reactor 40 through the reducing gas line 64 and the reformed reducing gas generated from the steelmaking by-product gas pretreatment facility 20. It is a device for preliminarily reducing or reducing the iron ore transferred from the raw material pretreatment facility 10 by using the reducing gas supplied through the line 60.

The pre-reduction / reduction reactor 30 may be connected in series or in parallel with one or two or more so as to adjust the reduction reaction rate for removing oxygen from the iron ore according to the iron ore particle size and reactor type. The pre-reduction / reduction reactor 30 is determined by the iron ore type and the appropriate reduction reaction temperature, pressure range, etc. If the reduction process of the iron ore in the form of a fixed bed (fixed bed), reduced and calcined at a high temperature of 900 ℃ or more It is also possible. The pre-reduction / reduction reactor 30 may connect several reactor types to each other. In particular, in the case of a fluidized bed (fluidized bed) reactor, the reaction temperature and the degree of fluidization should be controlled so as not to cause carbon deposition or sticking.

In general, in the case of hematite (hematite), it is well reduced at a temperature between 600 ~ 850 ℃ under a pressure higher than the atmospheric pressure, and in the case of magnetite (magnetite) it is well reduced at a temperature between 350 ~ 650 ℃. In addition, the reducing gas separated and separated from the steel by-product by-product pretreatment facility 20 for efficient reduction of low-grade iron ore such as hard-reduced ore is input and controlled according to the form and reduction of iron ore. If a large amount of hydrogen reducing agent is used, the reduction rate of the lower iron ore can be increased.

In addition, the molten reduction reactor 40 of the embodiment according to the present invention melts and reduces the partial reduced iron obtained from the preliminary reduction / reduction reactor 30 by using a hydrocarbon processing apparatus 80 for supplying high heat and reducing gas. 90) is a device for producing. The hydrocarbon processing device 80 is a device for burning coal pulverized in the form of pulverized coal, coke or briquettes so as to provide heat and reducing gas required for the reactor.

In this case, as a medium for controlling the calorific value, it is preferable to use pure oxygen rather than air in terms of carbon dioxide reduction. The insufficient driving force can be controlled by the introduction of hydrocarbons by the hydrocarbon (reduction gas) gas line 70 obtained from the steelmaking by-product gas pretreatment facility 20. In addition, it is also possible to reduce the amount of reducing gas and calorific value required in the reactor by accelerating the reduction melting rate by adding a large amount of hydrogen.

Hereinafter, a first embodiment according to the present invention will be described in more detail with reference to FIG. 2.

Figure 2 is a schematic diagram of a molten iron manufacturing apparatus of the first embodiment according to the present invention, the basic configuration and function is the same as in Figure 1, but according to the type and characteristics of iron ore to be reduced, the configuration of the invention is modified or additional devices are to be installed Can be.

In the first embodiment according to the present invention, a reactor in the form of a fluidized bed was used to promote indirect reduction of the lower iron ore present in the form of a fine reduction / reduction reactor. The fluidized bed reactor is to reduce the iron ore present in the form of fine powder by reducing gas such as carbon monoxide, hydrogen, etc., compared with using a fixed bed reactor of the blast furnace and shaft reactors, such as pellet or sintering process of iron ore This process can be simplified because there is no need, and iron ore is in the form of fine powder, so iron ore reduction rate is fast.

At this time, in the form of fine iron ore, the fluidized bed reactor is applied differently depending on the particle size and the iron ore density change. That is, all iron ore particles of several millimeters or less are preferred to combine several fluidized bed reactor types rather than requiring one reactor type in the reduction process, which results in carbon deposition or sticking phenomenon occurring when reducing finely divided iron ores. It is possible to achieve an efficient iron ore reduction process by reducing the, and by minimizing the scattering loss caused by the fluidized bed reactor type. This is possible by appropriate choice of fluidized bed reactors depending on the type of iron ore.

In the first embodiment according to the present invention, a riser-type fluidized bed reactor is generally used to reduce the magnetite-type fine iron ore, which is generally less than several hundred microns and has an average particle distribution of several tens of microns. A bubble fluidized bed reactor was applied for hematite-type fine iron ores with fine iron ore less than several millimeters and average particle distribution of several hundred microns. The fine iron ore is in contact with a reducing gas under appropriate reaction conditions to form reduced iron, it is possible to form a molten iron 90 in the melt reduction reactor (40).

The magnetite-based iron ore raw material is well reduced by the reducing gas containing a large amount of hydrogen as a reducing gas as shown in the following formula (1), and the iron ore indirect reduction reaction occurs well in the temperature range of 350 ~ 650 ℃.

1/4 Fe ₃ O ₄ + H ₂ ---> 3/4 Fe + H ₂ O -------------- (1)

Therefore, it is preferable that the iron ore of the magnetite series is mixed in the raw material pretreatment facility 10b to have a normal distribution of several tens of micron particle size and treated to be in the Geldart A range to be reduced in the riser 33 and 34. At this time, the iron ore with high moisture may be subjected to a drying process or the ore with high impurities may be accompanied by a pretreatment process by beneficiation. In general, fine magnetite which is present in tens of microns is reduced by using hydrogen, and the reduction reaction occurs faster than carbon monoxide as a reducing agent at a temperature of 800 ° C. or higher at the initial stage of the reduction reaction, thereby reducing the iron ore by a riser rather than a bubble fluidized bed. It is suitable to do. In this case, in the pretreatment process, the preliminary iron ore may be preheated to allow a (preliminary) reduction at a temperature of 800 ° C. or higher. The preheating can be performed by circulating and burning some of the gas discharged from the reduction reactor 32 to the fine magnetite raw material pretreatment facility 10b and raising the temperature to 800 ° C or higher.

In general, the reduction reaction of the magnetite system using hydrogen is rapidly reduced at a reduction temperature of 800 ° C. or higher until the iron ore reduction rate is 40-50% or less, but the reduction reaction rate is significantly reduced when the reduction rate is 40-50% or more. Therefore, in order to obtain an iron ore reduction rate of 50% or more, it is appropriate that the reaction temperature is 350 to 650 ° C or less. This is because the reduction rate is increased by reducing the fine magnetite with hydrogen, and the reduction reaction rate is inhibited by carbon deposition or sticking. For this purpose, it is appropriate to reduce by connecting two or more rising tubes for the reduction of the fine magnetite.

That is, the first riser 34 is adjusted so that the reduction rate is 40 to 50% at a temperature of 800 ℃ or more, and the second riser 33 is to accelerate the reduction reaction at 350 ~ 650 ℃ temperature.

The reduced iron thus obtained may be mixed with the reduced iron of the hematite system and reduced to be added to the melt reduction reactor 40. At this time, it is also possible to distinguish the reduced iron of the magnetite system and hematite system to be introduced into the melt reduction reactor (40). The reducing gas for reducing the iron ore of the magnetite system is advantageously reduced by using hydrogen gas produced from the steelmaking by-product gas pretreatment facility 20-1. However, the reducing gas may exist in the form of various mixed gases. In addition, the reactor used at this time is not limited to the riser, the type of iron ore is not limited to the iron ore of the magnetite system, it is possible to include a hematite system and a dust (iron) in the form of dust (dust) discharged as a by-product of the steelmaking process. In addition, the reduction reactor may be connected to two or more according to the reduction rate and the iron ore residence time.

Referring to FIG. 2, the iron ore raw material is supplied to the raw material pretreatment facility 10b for sorting and pretreating the iron ore raw material to be suitable for reduction through the iron ore raw material line 5b, and the iron ore raw material pretreated from the raw material pretreatment facility 10b. Is transferred to a preliminary reduction reactor, wherein the preliminary reduction reactor is a first riser 34 to which the pretreated iron ore raw material is transferred, and a second riser 33 connected to the first riser 34. Is done.

Iron ore raw material from the raw material pretreatment facility (10b) through the first ore conduit (52a), the second ore conduit (52b) and the third ore conduit (52c) sequentially the first riser (34), the second riser It is reduced while moving to 33 and the reduction reactor 32.

That is, the partial reduced iron transferred from the preliminary reduction reactors 33 and 34 in which the transferred iron ore raw material is pre-reduced by the reducing gas is reduced in the reduction reactor 32, and the partial reduced iron obtained from the reduction reactor 32 is melted. The molten iron 90 is produced by melt reduction using a reducing gas in the reduction reactor 40.

In addition, in FIG. 2, carbon dioxide generated in a steelmaking by-product gas or iron ore reduction process is mixed and reformed to generate a reducing gas, and the generated reducing gas is the molten reduction reactor 40 or the preliminary reduction reactors 33 and 34. The iron by-product by-product pretreatment facility 20-1 to supply to the iron ore reduction process facility 100-1 to supply the carbon dioxide is shown.

At this time, the steel by-product by-product pretreatment 20-1, the steel by-product off-gas separation device 21 for separating the hydrogen from the steel by-product by-product to supply the separated hydrogen to the second riser (33), The first heater 12a for supplying heat to the iron by-product gas from which hydrogen is separated by the heat exchange with the circulating gas in the circulating gas line 72 circulating through the raw material pretreatment facility 10b, and the generated hydrogen is It is connected to the first reforming reactor (20a) and the first reforming reactor (20a) supplied to the first riser (34) to the carbon generated from the first reforming reactor (20a) and the first heater (12a) The carbon dioxide generated by the complete combustion of the gas and carbon dioxide generated in the iron ore reduction process facility (100-1) to produce carbon monoxide and the produced carbon monoxide is supplied to the melt reduction reactor (40) Reactor 20b It should. At this time, the carbon supply to the second reforming reactor 20b is made through the carbon line 18.

Most of the seasonal by-product gas from which the hydrogen is supplemented by the first heater 12a is separated from the hydrogen, is mostly made of methane, and flows into the first heater 12a through the methane line 19, and the first reforming is performed. In the reactor 20a, hydrogen and carbon are generated by a reaction such as the following formula (2).

CH ₄ ---> C + 2H ₂ -------------------- (2)

At this time, the temperature of the gas circulated through the raw material pretreatment facility 10b is 800 ° C. or higher.

A part of the gas used in the first heater 12a may supply carbon dioxide to the second reforming reactor 20b by complete combustion, and at the same time, heat may be supplied by the second heater 12b. The remaining gas can be supplied to power plant 13a to produce power. Hydrogen gas generated in the first reforming reactor 20a is introduced into the first riser 34 and the hydrogen may be present at 800 ° C. or more, and the amount of heat insufficient is part of the gas discharged from the reduction reactor 32. It is also possible to supplement by using as a combustion gas. At this time, the hydrogen gas discharged from the second riser 33 may be replenished to the first riser 34 after heat exchange with the second heat exchanger 11b.

Hydrogen reducing agent gas in the first embodiment according to the present invention is the coke oven gas (COG) generated in the process of making coke from the steel mill and the gas discharged from the iron ore reduction process equipment 100-1 of the embodiment according to the present invention CO2 is recovered and reformed to produce. This is a technology that efficiently uses the gas generated in the coal-based steelmaking process.

The second reforming reactor 20b is supplied through the carbon dioxide line 37 recovered from the carbon (C) obtained from the first reforming reactor 20a and the iron ore reduction process facility 100 as shown in Equation (3) below. It is a device for obtaining carbon monoxide by reforming the carbon dioxide obtained from the second heater 12b for supplying heat to the carbon dioxide and the second reforming reactor 20b.

C + CO ₂ ---> 2CO -------------------- (3)

On the other hand, since the first riser 34 operates at 800 ° C. or higher, the reducing gas (hydrogen) supplied to the first riser 34 must satisfy a temperature of 800 ° C. or higher. Therefore, a first heat exchanger 11a is installed between the steelmaking by-product gas separator 21 and the second riser 33 to discharge from the first riser 34 and the second riser 33. The heat amount of the reducing gas supplied to the second riser 33 is replenished by heat exchange with hydrogen.

The heat exchange is performed through the primary riser discharge line 34a and the secondary riser discharge line 33a, respectively. At this time, high temperature hydrogen flows on the first riser discharge line 34a and the second riser discharge line 33a, and hydrogen of the hydrogen line 17a to which low temperature hydrogen is supplied from the first heat exchanger 11a. When the heat exchange is performed and the amount of hydrogen supplied is insufficient, hydrogen may be supplied to the second riser 33 after the heat exchange.

The second heat exchanger (11b) is installed on the second ore conduit (52b) connecting the first and the second riser (33, 34) to the hydrogen gas discharged from the second riser (33) After the heat exchange with the partial reduced iron flowing through the second ore conduit 52b, the first riser 34 is supplied. The hydrogen supplied to the first riser 34 after the heat exchange is mixed and supplied with the hydrogen supplied by the hydrogen line 17a supplied from the first reforming reactor 20a to the first riser 34.

The raw material pretreatment facility (10b) requires heat for pretreatment of iron ore raw material, the heat of the reducing gas of the reducing gas line 62d supplied from the reduction reactor 32 to the raw material pretreatment facility (10b) Supplied by (circulating gas). That is, the high temperature reducing gas flows through the circulating gas (reduction gas) line 72 after heating the raw material pretreatment facility 10b. Since the temperature of the reducing gas flowing through the circulating gas line 72 is also high, it is possible to heat exchange and combust the steel off-by-product gas from which the hydrogen is removed from the first heater 12a as described above.

Iron ore reduction process equipment (100-1) in the first embodiment according to the present invention is a second pre-reduction reactor (31) for reducing the iron ore raw material by the reducing gas supplied from the reduction reactor 32, and Second raw material pretreatment for supplying the iron ore raw material that has been screened and pretreated to be suitable for the second pre-reduction reactor 31 by the reducing gas supplied from the second pre-reduction reactor 31 to the second pre-reduction reactor 31. A carbon dioxide line (37) for separating carbon dioxide from the reducing gas line (62c) connected to the facility (10a) and the second raw material pretreatment (10a) and supplying carbon dioxide to the steelmaking by-product gas pretreatment (20-1). Include. Iron ore raw materials are reduced while being sequentially transferred to the second preliminary reduction reactor 31 and the reduction reactor 32 through the fifth ore conduit 52e and the fourth ore conduit 52d.

The iron ore reduction process equipment 100-1 according to the present invention flows to the second preliminary reduction reactor 31 and the second raw material pretreatment equipment 10a sequentially through reducing gas lines 62a and 62b, and reduces gas lines ( Through 62c) some of the reducing gas is stored in the power plant (13b), the remaining reducing gas is separated into carbon dioxide.

Separation of the carbon dioxide is made in the carbon dioxide separator 14, the separated carbon dioxide is supplied to the second reforming reactor 20b through the carbon dioxide line 37, the reducing gas separated in the carbon dioxide separator 14 Is mixed with a reducing gas line 64 flowing into the reduction reactor 32 from the melt reduction reactor 40 through a reducing gas line 66 and supplied to the reduction reactor 32.

In this case, a carbon dioxide storage device 15 may be installed on the carbon dioxide line 37.

In the iron ore reduction process for supplying carbon dioxide in the first embodiment according to the present invention, hematite-based fine iron ore having a mean particle distribution of several hundred microns is used as a reducing gas, and a reducing gas containing a large amount of carbon monoxide is used. It is produced by reducing iron and reduced more easily in the temperature range of 600 ~ 850 ℃. Reaction formula at this time is as following formula (4).

1/3 Fe ₂ O ₃ + CO ---> 2/3 Fe + CO ₂ -------------- (4)

In the embodiment according to the present invention mainly hematite-based iron ore is mixed in a second raw material pretreatment (10a) to have a normal distribution of several hundred microns particle size is reduced using a bubble fluidized bed reactor of Geldart B particle fluidization. At this time, the iron ore with high moisture may be subjected to a drying process, or the ore with high impurities may be accompanied by a pretreatment process by beneficiation.

After the pretreatment process, the iron ore is mixed with the reducing iron ore of the magnetite system through a reduction reactor 31 using a reducing gas containing a large amount of carbon monoxide rising from the molten reduction reactor 40 to be reduced in the reduction reactor 32. It is also possible. At this time, the reduction temperature is made in the range of 650 ℃ ~ 800 ℃ to promote the reduction by a large amount of carbon monoxide. The form of the reducing gas generally favors a large amount of carbon monoxide rising from the melt reduction reactor, but can be present in the form of various mixed gases. In addition, the reactor used at this time is not limited to the bubble fluidized bed reactor, the type of iron ore is not limited to the iron ore of the hematite system, it is possible to include a dust (iron) in the form of dust (iron) discharged as a by-product of iron and iron process. Do.

Carbon dioxide recovered from the iron ore reduction process facility (100-1) is by-product gas discharged from the second raw material pretreatment facility (10a) or the second pre-reduction reactor (31) to a power plant (13b) to produce power in part. After being supplied and the remainder is recovered as a recycle gas during the process to be separated into carbon dioxide in the carbon dioxide separation unit 14, some may be introduced into the second reforming reactor 20b and the rest may be stored underground by the carbon dioxide storage unit 15. . The reducing gas separated by the carbon dioxide separator 14 is mixed with the reducing gas rising in the melt reduction reactor 40 and re-introduced into the reduction reactor 32. The reforming reactor may be in the form of a fixed bed or fluidized bed, but the fluidized bed is preferred. Carbon monoxide obtained from the second reforming reactor 20b may be introduced into the melt reduction reactor 40.

  The molten reduction reactor 40 produces the molten iron 90 by melting and reducing the partially reduced iron obtained from the reduction reactor 32 using hydrocarbon treatment devices 80a and 80b for supplying high heat and reducing gas.

The hydrocarbon processing apparatus (80a, 80b) burns pulverized coal, coke or briquette coal mass to provide the heat and reducing gas required for the reactor. In this case, it is preferable to use pure oxygen rather than air in terms of carbon dioxide reduction as a medium for controlling the calorific value, and the driving force insufficient for infiltrating the reducing gas and securing the space in the reactor when the pure oxygen is injected through the oxygen line 85 is The carbon monoxide obtained from the second reforming reactor 20b can be regulated by supplying it through the reducing gas line 68. In case of lack, it may be separately supplied through the hydrocarbon supply line 80b.

Hereinafter, a second embodiment according to the present invention will be described with reference to FIG. 3.

Figure 3 shows a schematic view of the molten iron manufacturing apparatus of the second embodiment according to the present invention, the configuration and function of the molten iron manufacturing apparatus of the second embodiment is the same as in the first embodiment unless otherwise described, but iron and steel by-products The method of carbon dioxide recovery and by-product gas reforming in the gas separation device 20-2 may be modified or additional additional devices may be installed.

The flow in the fluidized bed reduction reactor of the fine iron ore in the second embodiment is the same as in the first embodiment, and the fine iron ore in the hematite system is reduced in the riser in the bubble fluidized bed reactor, respectively, and then reduced. At the same time, the mixture is reduced in the reactor 32 and introduced into the melt reduction reactor 40. However, the flow of the reducing gas of the fine iron ore reduction reactor 32 may be modified by by-product gas reforming and reducing gas circulation.

In the second embodiment according to the present invention, the hydrogen gas separated from the steelmaking by-product gas pretreatment facility 20-2 using COG, which is steel by-product gas, passes through the hydrogen line 17a. 34) After the heat exchanged from the discharged hydrogen gas and the first heat exchanger (11a) is introduced into the second riser (33).

In addition, a gas excluding hydrogen from iron by-product gas such as COG or FOG (FINEX OFF GAS) mainly consists of methane gas. The methane gas is circulated through a raw material pretreatment system (10b) by using a circulating gas of 800 ° C. or higher. The amount of heat is replenished by the third heat exchanger 11c and then introduced into the third reforming reactor 20c. At this time, the circulating gas circulated through the raw material pretreatment facility 10b passes through the third heat exchanger 11c, and part of the circulating gas is supplied to the power plant 13a to produce electric power, and the rest of the third reforming reactor ( It is also possible to supply carbon dioxide at the same time as supplying heat to 20c).

Another source of carbon dioxide supplied to the third reforming reactor (20c) is to recycle a portion of the gas discharged from the second raw material pretreatment (10a) or the second pre-reduction reactor (31) to steam-gas reforming reactor (25) And hydrogen separation apparatus 27 to separate hydrogen and can be obtained from the discharged gas. At this time, the separated hydrogen is heat-exchanged in the fourth heat exchanger (11d) and the gas of the reducing gas line 64, which is connected to the melt reduction reactor 40 and the reduction reactor 32 to supply the reducing gas to the reduction reactor 32. Then, it may be supplied as a reducing gas to the first riser 34 through the hydrogen line 17c.

At this time, the hydrogen passing through the fourth heat exchanger (11d) is heated by heat exchange with the reducing gas supplied to the raw material pretreatment (10b) in the reduction reactor 32 can be supplied to the first riser (34). have.

Some of the gas discharged from the hydrogen separation device 27 is stored underground by the carbon dioxide storage device 15, and the rest is transferred to the third reforming reactor 20c, and hydrogen and carbon monoxide are shown in Equation 5 below. Produces reducing gas.

CH ₄ + CO ₂ ---> 2CO + 2H ₂ ---------------------- (5)

Carbon dioxide that is not completely reacted in the third reforming reactor 20c may be recovered by the carbon dioxide recycling line 22 and recycled into the third reforming reactor 20c. The reducing gas produced from the third reforming reactor 20c may be introduced into the melt reduction reactor 40 through the reducing gas line 68 to accelerate the melt reduction reaction. In addition, it is possible to reduce the amount of reducing gas and calorific value required in the reactor by accelerating the reduction melting rate by adding a large amount of hydrogen. The rest of the configuration is the same as in the first embodiment. However, it is not limited only to the above-mentioned variations.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, You will understand.

It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be interpreted as being included in the scope of the present invention .

Claims (34)

A raw material pretreatment system for sorting and pretreating iron ore raw materials to be suitable for reduction;
And a first rising pipe to which the pretreated iron ore raw material is transferred from the raw material pretreatment facility, and a second rising pipe connected to the first rising pipe, wherein the transferred iron ore raw material is pre-reduced by reducing gas. Pre-reduction reactor;
A reduction reactor for reducing the partial reduced iron transferred from the pre-reduction reactor;
A molten reduction reactor producing molten iron by melting and reducing the partially reduced iron obtained from the reduction reactor using a reducing gas;
A steel off-product by-product pretreatment system for mixing and reforming carbon dioxide generated in a steelmaking by-product gas or iron ore reduction process and supplying the generated reducing gas to the melt reduction reactor or the pre-reduction reactor; And
An iron ore reduction process facility for supplying carbon dioxide generated in the iron ore reduction process;
A molten iron manufacturing apparatus comprising a. The method of claim 1,
The iron ore reduction process equipment,
A second pre-reduction reactor for preliminarily reducing the iron ore raw material by the reducing gas supplied from the reduction reactor;
A second raw material pretreatment facility for supplying the iron ore raw material that has been screened and pretreated to be suitable for the second pre-reduction reactor by the reducing gas supplied from the second pre-reduction reactor; And
A carbon dioxide line separating carbon dioxide from a reducing gas line connected to the raw material pretreatment facility and supplying carbon dioxide to the steelmaking by-product gas pretreatment facility;
A molten iron manufacturing apparatus comprising a. 3. The method of claim 2,
The steel off-product by-product pretreatment facility,
An iron by-product off-gas separator for separating hydrogen from iron by-product gas to supply the separated hydrogen to the second riser;
A first heater for supplying heat to the iron by-product gas from which the hydrogen is separated by heat exchange with a circulating gas circulating through the raw material pretreatment facility;
A first reforming reactor for generating hydrogen and carbon as the iron-based by-product gas from which the hydrogen supplemented by the first heater is separated, and supplying the generated hydrogen to the first riser; And
It is connected to the first reforming reactor and introduced with carbon generated from the first reforming reactor, carbon dioxide generated by the combustion of the gas used in the first heater and carbon dioxide generated in the iron ore reduction process equipment to produce carbon monoxide. The produced carbon monoxide manufacturing apparatus, characterized in that it comprises a second reforming reactor for supplying the melt reduction reactor. The method of claim 3,
And a second heater for supplying heat to the second reforming reactor. 3. The method of claim 2,
The steel off-product by-product pretreatment facility,
A steelmaking by-product gas separator for separating hydrogen and supplying the separated hydrogen to the second riser;
A first heater for replenishing heat by circulating gas circulating the hydrogen by-product by-product separated from the hydrogen through the raw material pretreatment facility; And
The carbon dioxide generated by the combustion of the gas used in the first heater and the carbon dioxide generated in the iron ore reduction process equipment is introduced to produce a reducing gas containing hydrogen and carbon monoxide and the produced reducing gas is the melt reduction reactor And a third reforming reactor for supplying to the molten iron manufacturing apparatus. The method of claim 1,
The first riser is operated at 800 ℃ or more, the second riser is a molten iron manufacturing apparatus, characterized in that operating in the 350 ~ 650 ℃ range. 7. The method according to any one of claims 1 to 6,
A first heat exchanger is installed between the steelmaking by-product gas separator and the second riser to reduce the amount of reducing gas supplied to the second riser by heat exchange with hydrogen discharged from the first riser and the second riser. The molten iron manufacturing apparatus characterized by replenishing calories. 7. The method according to any one of claims 1 to 6,
It is installed on the second ore conduit connecting the first and the second riser to supply the hydrogen gas discharged from the second riser to the first riser after heat exchange with the partial reduced iron flowing through the second ore conduit The molten iron manufacturing apparatus characterized in that the second heat exchanger is installed. 7. The method according to any one of claims 1 to 6,
The raw material pretreatment facility is a molten iron manufacturing apparatus characterized in that the heat is supplied from the reducing gas line for supplying the reducing gas from the reduction reactor. 3. The method of claim 2,
The molten iron reactor is characterized in that the hydrocarbon processing device for supplying high heat and reducing gas is installed in the melt reduction reactor. The method of claim 10,
The molten iron reactor is characterized in that the oxygen line for supplying pure oxygen is installed in the melt reduction reactor. The method according to claim 10 or 11,
The hydrocarbon processing apparatus is a molten iron manufacturing apparatus, characterized in that for burning coal pulverized coal, coke and briquette form. 3. The method of claim 2,
And a carbon dioxide separation device connected to the reducing gas line to separate carbon dioxide from the reducing gas. The method of claim 13,
And a carbon dioxide line connected to the carbon dioxide separator to supply a reducing gas passed through the carbon dioxide separator to a reduction reactor, and a carbon dioxide line to supply the separated carbon dioxide to the steel by-product pretreatment facility. Molten iron manufacturing apparatus. 15. The method of claim 14,
And a carbon dioxide storage device installed on the carbon dioxide line to store the separated carbon dioxide. 3. The method of claim 2,
A steam-gas reforming reactor connected to the second raw material pretreatment plant for reforming the gas discharged through the second raw material pretreatment facility to generate steam; And
A hydrogen separation device connected to the steam-gas reforming reactor to separate the generated steam and carbon dioxide;
The molten iron manufacturing apparatus characterized in that it further comprises. 17. The method of claim 16,
A carbon dioxide line connected to the hydrogen separation device to supply the separated carbon dioxide to a steelmaking by-product gas pretreatment facility, and a hydrogen line connected to the hydrogen separation device to supply the separated hydrogen to the reduction reactor and the first riser. A molten iron manufacturing apparatus comprising a. 18. The method of claim 17,
And a fourth heat exchanger configured to replenish a heat source to hydrogen in the hydrogen line by heat exchange with gas supplied from the melt reduction reactor to the reduction reactor on the hydrogen line. 19. The method of claim 18,
And a carbon dioxide storage device installed on the carbon dioxide line to store the separated carbon dioxide. 20. The method of claim 19,
And a third heater is provided on a reducing gas line connected to the raw material pretreatment facility from the hydrogen line and the reduction reactor so as to replenish the heat amount to the hydrogen passing through the fourth heat exchanger. A raw material pretreatment step of pretreating the iron ore raw material to be suitable for reduction;
Transferring the pretreated raw material to a pre-reduction reactor including a first riser and a second riser to pre-reduce by reducing gas;
Reducing the partially reduced iron that was pre-reduced and transferred to the reduction reactor;
A melt reduction step of producing molten iron by melting and reducing the partially reduced iron obtained from the reduction reactor using a reducing gas;
A steel off-product by-product pretreatment step of mixing and modifying carbon dioxide generated in a steelmaking by-product gas and an iron ore reduction process and supplying the generated reducing gas to the melt reduction step or the pre-reduction step; And
An iron ore reduction step of supplying carbon dioxide generated in the iron ore reduction step;
The molten iron manufacturing method comprising a. The method of claim 21,
The steel off-product by-product pretreatment step,
Separating hydrogen from the steelmaking by-product gas and supplying the separated hydrogen to the first riser;
The iron by-product gas from which the hydrogen is separated is heated by heat exchange with a circulating gas circulated through the raw material pretreatment facility and supplied to the first reforming reactor to produce carbon and hydrogen to supply the produced hydrogen to the pre-reduction reactor. Doing;
Supplying the produced carbon, carbon dioxide generated by the heating, and carbon dioxide generated in the iron ore reduction process step into a second reforming reactor to produce carbon monoxide and supplying the produced carbon monoxide to the melt reduction reactor;
The molten iron manufacturing method comprising a. The method of claim 21,
The steel off-product by-product pretreatment step,
Separating hydrogen from the iron by-product gas and supplying the separated hydrogen to the pre-reduction reactor;
Heating the iron by-product gas from which the hydrogen is separated by heat exchange with a circulating gas circulating through the raw material pretreatment facility; And
Supplying the heated hydrogen by-product off-gas to the third reforming reactor to produce a reducing gas including carbon and hydrogen, and supplying the produced reducing gas to the melt reduction reactor;
The molten iron manufacturing method comprising a. 24. The method of claim 23,
The unreacted carbon dioxide in the reducing gas production step is recovered and recycled back to the third reforming reactor further comprising the step of producing a molten iron. The method of claim 21,
The raw material pretreatment step,
The method of manufacturing a molten iron, characterized in that the step of performing the pre-heating by receiving the heat amount by the reducing gas discharged from the reduction reactor by modifying the iron ore raw material or by adjusting the components. 26. The method of claim 25,
The iron ore raw material is a molten iron manufacturing method, characterized in that the fine form of any one or more of hematite, magnetite, moisture-containing iron ore or steelmaking process dust (dust). The method of claim 21,
The first riser is operated at 800 ℃ or more, the second riser is a molten iron manufacturing method characterized in that operating in the range of 350 ~ 650 ℃. 24. The method according to claim 22 or 23,
Hydrogen separated from the steelmaking by-product gas is supplied to the second riser by heat exchange with hydrogen discharged from the first riser and the second riser. 24. The method according to claim 22 or 23,
It is installed on the second ore conduit connecting the first and the second riser, the hydrogen gas discharged from the second riser and heat-exchanged with the partial reduced iron flowing through the second ore conduit, the first riser The molten iron manufacturing method characterized in that the supply to. The method of claim 22 or 23,
The melt reduction step,
Receiving a high heat and reducing gas supplied by a hydrocarbon processing device connected to the melt reduction reactor, the molten iron manufacturing method characterized in that it further comprises the step of receiving pure oxygen through an oxygen line. The method of claim 21,
The iron ore reduction process step,
Pre-reducing the iron ore raw material by the reducing gas supplied from the reduction reactor to the second pre-reduction reactor;
Supplying iron ore raw material pre-treated to be suitable for the second pre-reduction reactor by the reducing gas supplied from the second pre-reduction reactor to the second raw material pretreatment facility to the second pre-reduction reactor; And
A carbon dioxide separation supply step of separating carbon dioxide from the reducing gas discharged from the second pre-reduction reactor and supplying it to the steelmaking by-product gas pretreatment step;
The molten iron manufacturing method comprising a. 32. The method of claim 31,
The separation of the carbon dioxide is a molten iron manufacturing method, characterized in that made by a carbon dioxide separator or a hydrogen separator connected to the second raw material pretreatment equipment. 33. The method of claim 32,
A steam-gas reforming reactor is installed at the front end of the hydrogen separation device to produce steam from reducing gas introduced from the second raw material pretreatment facility. 33. The method of claim 32,
Hydrogen separated from the hydrogen separation device is heated by heat exchange with the reducing gas supplied from the melt reduction reactor to the reduction reactor is supplied to the first riser, characterized in that the molten iron.

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