KR20240076517A - Reduction reactor and manufacturing method of direct reduced iron - Google Patents

Abstract

A reduction reactor according to an embodiment of the present invention includes a container having an internal space capable of accommodating a raw material containing iron ore and a reducing gas, a plurality of holes through which the reducing gas can pass, and a dispersing member installed inside the container. and a burner installed on the upper side of the dispersion member at a height spaced apart from the dispersion member determined using the target flow rate of the reducing gas to be supplied into the container and capable of generating a flame inside the container.
Therefore, according to embodiments of the present invention, it is possible to suppress or prevent the dispersion member from being heated to a high temperature by the heat of the flame generated from the burner. Additionally, it is possible to generate a flame at a lower temperature than before. Accordingly, agglomeration due to melting of raw material particles can be suppressed or prevented, and thus the formation of a stagnation layer can be suppressed or prevented. Therefore, raw materials can flow smoothly inside the reduction furnace.
In addition, while suppressing or preventing the formation of a stagnation layer, sufficient heat can be applied to the raw materials and reducing gas to ensure that the reduction reaction occurs smoothly.

Description

Reduction furnace and manufacturing method of reduced iron {REDUCTION REACTOR AND MANUFACTURING METHOD OF DIRECT REDUCED IRON}

The present invention relates to a reduction furnace and a method for producing reduced iron, and more specifically, to a reduction furnace and a method for producing reduced iron that can facilitate the flow of raw materials.

The blast furnace process requires several auxiliary facilities such as coke manufacturing equipment and sinter ore manufacturing equipment. In addition, there is a problem that environmental pollution occurs due to substances discharged from auxiliary equipment and the cost of environmental pollution prevention equipment increases.

Therefore, a method of manufacturing molten iron by directly using powdered iron ore, which accounts for more than 80% of the world's ore production, is being used. This molten iron manufacturing facility includes a fluidized reduction furnace for producing reduced iron by reducing powdered iron ore, and a melting device for producing molten iron by melting the reduced iron provided from the fluidizing reduction furnace.

The fluidized reduction furnace includes a container and a dispersing member having a plurality of holes through which gas can pass. The dispersing member is installed inside the container, reducing gas is supplied to the lower side of the dispersing member, and powdered iron ore is charged to the upper side of the dispersing member.

When reducing gas is supplied to the lower side of the dispersing member, the reducing gas passes through a plurality of holes provided in the dispersing member and is injected upward. The powdered iron ore on the upper side of the dispersing member flows due to the reducing gas injected upward in this way. And while the powdered iron ore flows, it reacts with the reducing gas, and the powdered iron ore is reduced and produced into reduced iron.

In order for the powdered iron ore and reducing gas to react smoothly inside the fluidized reduction furnace, the interior of the fluidized reduction furnace must be maintained above a predetermined temperature. However, since the reaction between powdered iron ore and reducing gas is a predominantly endothermic reaction, the temperature inside the fluidized reduction furnace may decrease during the reduction reaction. To solve this problem, a burner is installed in the fluidized reduction furnace to generate a flame, thereby heating the fluidized reduction furnace. At this time, the burner is installed to be located above the dispersion member.

On the other hand, if the temperature of the flame generated from the burner is too high, the powdered iron ore particles may melt and stick together. And when the powdered iron ore particles clump together and form a lump, the powdered iron ore does not flow smoothly. As a result, a stagnation phenomenon occurs in which powdered iron ore does not flow or only small flows occur.

Additionally, if the temperature of the flame is too high or the distance between the burner and the dispersion member is short, the temperature of the dispersion member becomes high. In this case, the powdered iron ore particles are melted by the heat of the dispersing member and become entangled together, which causes the holes of the dispersing member to become clogged. If the hole of the dispersion member is blocked, the reducing gas cannot pass through, so there is a problem in that the flow of powdered iron ore on the upper side of the dispersion member is not smooth.

Korean Patent Publication No. 10-2007-0068210

The present invention provides a reduction furnace and a method for producing reduced iron that can suppress or prevent stagnation of the flow of raw materials.

The present invention provides a reduction furnace and a method for producing reduced iron that can suppress or prevent the holes of the dispersion member from being closed.

The present invention provides a reduction furnace capable of lowering the temperature of the flame and a method for producing reduced iron.

A reduction reactor according to an embodiment of the present invention includes a container having an internal space capable of accommodating a raw material including iron ore and a reducing gas; a dispersing member installed inside the container and having a plurality of holes through which the reducing gas can pass; and a burner installed on an upper side of the dispersion member at a height spaced apart from the dispersion member determined using the target flow rate of the reducing gas to be supplied into the container and capable of generating a flame inside the container. .

The installation height of the burner is a height determined using at least one of the diameter of the hole provided in the dispersion member (d _or ) and the flow rate (u _or ) of the reducing gas, which are adjusted according to the target flow rate of the reducing gas.

The height at which the burner is installed may be greater than or equal to the depth (l _j ) at which the reducing gas penetrates into the raw material layer made of raw materials supplied to the upper side of the dispersing member, and may be less than or equal to the upper height of the raw material layer.

The burner includes a body extending in one direction; and a plurality of nozzles installed inside the main body, which extend in the direction in which the main body extends and whose distance between them becomes closer as they get closer to one end of the main body.

The tilt angle of each of the plurality of nozzles may be 20° to 45°.

The plurality of nozzles may be provided symmetrically with respect to the radial center of the main body.

The method for producing reduced iron according to an embodiment of the present invention is to determine the installation height (H _b ) of the burner based on the dispersion member installed inside the container using the target flow rate of the reducing gas to be supplied to the container of the reduction furnace. procedure; A process of installing a burner in the container such that the distance from the dispersion member to the upper side is the determined installation height (H _b ); A process of supplying raw materials including iron ore to the upper side of the dispersion member; A process of passing a reducing gas through a hole of the dispersion member to flow the raw material on the upper side of the dispersion member; A process of generating a flame inside the container using the burner; and a process of reducing the raw material by reacting the raw material with a reducing gas.

Before determining a height (H _b ) to install the burner, determining a target flow rate of the reducing gas; and determining the flow rate (u _or ) of the reducing gas to be supplied to the container using the determined target flow rate of the reducing gas and the diameter (d _or ) of the hole provided in the dispersion member.

The process of determining the installation height (H _b ) of the burner _{is the} depth ( The process of predicting l _j ); And it may include a process of determining the height (H _b ) at which the burner will be installed at a height higher than the predicted penetration depth (l _j ).

The process of predicting the depth (l _j ) at which the reducing gas penetrates into the raw material layer includes the diameter of the hole (d _or ), the flow rate of the reducing gas (u _or ), the density of the reducing gas (ρ _g ), and the raw material particles. It may include a process of calculating the penetration depth (l _j ) of the reducing gas using the density (ρ _s ), the particle size of the raw material particles (d _p ), and the dynamic viscosity (μ) of the reducing gas.

The height (H _b ) at which the burner is to be installed may be determined in a range that is greater than or equal to the predicted penetration depth (l _j ) and less than or equal to the upper height of the raw material layer.

The process of generating a flame inside the container using the burner includes supplying an oxidizing agent to each of a plurality of nozzles provided in the burner; forming an oxidizing agent stream by spraying an oxidizing agent from each of the plurality of nozzles; A process of colliding a plurality of the oxidant streams to spread the oxidant streams; and a process of generating a flame by reacting the oxidizing agent stream with the reducing gas.

The process of spraying the oxidizing agent from each of the plurality of nozzles may include spraying the oxidizing agent from each of the plurality of nozzles so that the oxidizing agent injected from each of the plurality of nozzles has an inclined flow that becomes closer to the radial center of the burner as the distance from the burner increases. You can.

The oxidizing agent may include oxygen (O) and nitrogen (N ₂ ).

It may include a process of adjusting the flow rate of the oxidant sprayed from each of the plurality of nozzles to 80 m/sec to 100 m/sec.

The reducing gas may include hydrogen (H ₂ ) gas.

According to embodiments of the present invention, it is possible to suppress or prevent the dispersion member from being heated to a high temperature by the heat of the flame generated from the burner. Additionally, it is possible to generate a flame at a lower temperature than before. Accordingly, agglomeration due to melting of raw material particles can be suppressed or prevented, and thus the formation of a stagnation layer can be suppressed or prevented. Therefore, raw materials can flow smoothly inside the reduction furnace.

In addition, while suppressing or preventing the formation of a stagnation layer, sufficient heat can be applied to the raw materials and reducing gas to ensure that the reduction reaction occurs smoothly.

1 is a diagram schematically showing a molten iron manufacturing facility of the present invention.
Figure 2 is a diagram showing a reduction furnace according to an embodiment of the present invention.
Figure 3 is an enlarged cross-sectional view of a portion of the reduction furnace.
Figure 4 is a front cross-sectional view of a burner according to an embodiment of the present invention.
Figure 5 is a plan view of a burner according to an embodiment of the present invention.
Figure 6 is a diagram explaining the flow of oxidant sprayed from a burner according to an embodiment of the present invention.
Figure 7 is a diagram schematically showing an experimental reduction reactor.
Figure 8 shows the results of measuring the temperature in the horizontal direction at a predetermined height of the experimental reduction furnace.
Figure 9 shows the results of measuring the temperature of the area from the dispersion member to a predetermined height upward in the experimental reduction furnace.
Figure 10 is a result showing the temperature distribution by height inside the container when a first type burner with one nozzle is installed in the container of an experimental reduction furnace to generate a flame.
Figure 11 is a result showing the temperature distribution by height inside the vessel when a second type of burner having first and second nozzles is installed in the vessel of an experimental reduction furnace to generate a flame.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the attached drawings. However, the present invention is not limited to the embodiments disclosed below and will be implemented in various different forms. These embodiments only serve to ensure that the disclosure of the present invention is complete and to fully convey the scope of the invention to those skilled in the art. This is provided to inform you. The drawings may be exaggerated to explain embodiments of the present invention, and like symbols in the drawings refer to like elements.

1 is a diagram schematically showing a molten iron manufacturing facility of the present invention.

Referring to FIG. 1, the molten iron production facility according to an embodiment of the present invention includes a reduced iron production device 2000 having a reduction unit 2100 capable of producing reduced iron and a dissolution device 3000 capable of dissolving reduced iron. Includes. In addition, the molten iron manufacturing facility includes a raw material supply device 1000 installed to supply raw materials to the reduction unit 2100 and a melting device 3000 to supply exhaust gas discharged from the melting device 3000 to the reduction section 2100. It may include an exhaust gas supply line 4000 installed to connect the reduction unit 2100.

In addition, the molten iron manufacturing facility may further include a molding device (not shown) that molds the powdered reduced iron produced in the reduced iron manufacturing device 2000.

The raw material supply device 1000 is installed to supply raw materials to the reduction unit 2100. Here, the raw material may include iron ore, and the iron ore may include finely divided iron ore whose particle size is greater than 0 mm and less than or equal to 0 mm. The raw material supply device 1000 may include, for example, a storage device capable of storing raw materials. Raw materials may be stored in the internal space of the storage unit for a long time, or may be temporarily stored before supplying the raw materials to the reduced iron manufacturing apparatus 2000. Such a reservoir may include, for example, a hopper.

The dissolution device 3000 receives reduced iron from the reduced iron production device 2000 and dissolves the supplied reduced iron. At this time, the dissolving device 3000 may be fine reduced iron or reduced iron prepared by agglomerating fine reduced iron in a molding device.

The dissolution device 3000 may be a device that dissolves reduced iron using, for example, electric heat. That is, the dissolving device 3000 may be a device that dissolves reduced iron using electrical energy. In addition, the melting device 3000 may receive additional iron scrap in addition to reduced iron and melt the reduced iron and iron scrap together. This dissolution device 3000 may include an electric furnace having a dissolution space capable of dissolving reduced iron using electric heat. Such an electric furnace may include an electric furnace main body 3100 having a dissolution space and an electrode 3200 at least partially disposed in the dissolution space to generate electric heat. In an electric furnace, when reduced iron is charged into the dissolution space, power is applied to the electrode 3200 to melt the reduced iron, thereby producing molten iron. Additionally, the exhaust gas generated during the manufacture of molten iron in an electric furnace may be supplied to the reduction unit 2100 through the exhaust gas supply line 4000.

When reduced iron is dissolved in the dissolution device 3000, gas is generated, and the gas contains at least one of CO (carbon monoxide) and CH ₄ (methane), which are flammable components. CO (carbon monoxide) and CH ₄ (methane) mentioned above are components that can be reduced with iron ore. Accordingly, the gas generated and discharged from the dissolution device 3000 (hereinafter referred to as exhaust gas) is recovered and supplied to the reduction section of the reduced iron production device. And in the reduced iron production device, iron ore is reduced using exhaust gas supplied from the dissolution device 3000. At this time, the exhaust gas discharged from the dissolving device 3000 may be supplied to the reduction unit 2100 through the exhaust gas supply line 4000.

In the above, it was explained that the dissolution device 3000 includes an electric furnace. However, the melting device 3000 is not limited to this and may include a melting gasification furnace. Inside the melt gasifier, a coal-filled bed made of coal is formed. Reduced iron and auxiliary raw materials are then introduced into the melting gasifier, and oxygen is blown in through a number of tuyeres installed on the outer wall. Accordingly, the coal-filled bed is burned by blown oxygen, which melts the reduced iron and produces molten iron. In addition, the exhaust gas generated during the production of molten iron in the melting gasifier may be supplied to the reduction unit 2100 through the exhaust gas supply line 4000.

The reduced iron production apparatus 2000 includes a reduction unit 2100 that reduces iron ore to produce reduced iron. Additionally, the reduced iron manufacturing apparatus 2000 may include a hydrogen gas supply unit 2200 that supplies a reducing gas containing hydrogen to the reduction unit 2100.

First, the hydrogen gas supply unit 2200 will be described. The hydrogen gas supply unit 2200 supplies hydrogen gas, which is a reducing gas for reducing the raw material, that is, iron ore, to the reduction unit 2100. Meanwhile, by-products generated when reducing raw materials in the reduction unit 2100 include water vapor, hydrogen gas, nitrogen gas, and carbon dioxide gas. The hydrogen gas supply unit 2200 may be a means provided to process by-products generated and discharged from the reduction unit 2100 to produce hydrogen gas, and to supply this hydrogen gas to the reduction unit 2100.

This hydrogen gas supply unit 2200 includes an exhaust pipe 2210 connected to the reduction unit 2100 to discharge by-products generated in the reduction unit 2100, and an exhaust pipe 2210 to receive the by-products and extract hydrogen gas. ), an extractor 2220 connected to the extractor 2220, a supply pipe 2230 installed to connect the extractor 2220 and the reduction unit 2100 so that hydrogen gas extracted or generated in the extractor 2220 can be supplied to the reduction unit 2100, and It may include a heater 2240 installed on the extension path of the supply pipe 2230 to heat the hydrogen gas generated in the extractor 2220. In addition, the hydrogen gas supply unit 2200 may further include a dust collector 2250 installed in the exhaust pipe 2210 to collect dust such as fine particles from by-products.

The dust collector 2250 may be installed in the exhaust pipe 2210 to be located between the extractor 2220 and the reduction unit 2100. Additionally, the dust collector 2250 may be, for example, a wet dust collector that collects dust using a wet method. Of course, the dust collector 2250 is not limited to the above-described example, and various means for collecting dust from by-products may be applied.

The extractor 2220 extracts hydrogen gas from the by-products discharged from the reduction unit 2100. As described above, by-products discharged from the reduction unit 2100 include water vapor, hydrogen gas, nitrogen gas, and carbon dioxide gas. The extractor 2220 extracts hydrogen gas from the by-products supplied from the exhaust pipe 2210. This extractor 2220 may be a means of extracting hydrogen gas from by-products, for example, by using a pressure swing absorption (PSA) method. That is, the pressure swing adsorption method extracts gas using the adsorption selectivity of each component with respect to the adsorbent, and the extractor 2220 adsorbs the hydrogen component to extract hydrogen gas from by-products containing various gases in addition to hydrogen gas. Carbon molecular sieve can be used as an adsorbent. At this time, the hydrogen component adsorbed on the adsorbent can be desorbed and extracted as hydrogen gas, and the extractor 2220 can extract hydrogen gas from the by-product by repeatedly performing adsorption and desorption of the hydrogen component.

Hydrogen gas extracted from the extractor 2220 is supplied to the reduction unit 2100 through the supply pipe 2230. The hydrogen gas supplied to the reduction unit 2100 can be used to reduce iron ore in the reduction unit 2100. That is, the hydrogen gas supplied to the reduction unit 2100 reduces iron ore. Accordingly, the hydrogen gas supplied to the reduction unit 2100 may be called 'reduction gas' that reduces iron ore.

In the reduction unit 2100, the raw material containing iron ore reacts with hydrogen gas extracted from the extractor 2220 to reduce iron ore. At this time, since the reaction between iron ore and hydrogen gas is a strong endothermic reaction, reaction efficiency can be improved when the hydrogen gas supplied to the reduction unit 2100 is heated to a temperature of 800°C or higher, more preferably 850°C or higher. Therefore, the heater 2240 is installed on the extension path of the supply pipe 2230 to be located between the extractor 2220 and the reduction unit 2100. The heater 2240 heats the hydrogen gas supplied from the extractor 2220, and the heated hydrogen gas is supplied to the reduction unit 2100 through the supply pipe 2230. Various means can be applied to heat hydrogen gas by direct heating or indirect heating.

In order to reduce all the iron ore supplied to the reduction unit 2100, a sufficient amount of hydrogen gas must be supplied. Additionally, since hydrogen gas is generally very expensive, there is a problem in that it requires a high cost to separately purchase hydrogen gas and supply it to the reduction unit 2100. However, in the embodiment, hydrogen gas is extracted from the by-products discharged from the reduction unit 2100 and supplied back to the reduction unit 2100 to be used as a reduction gas. In other words, the by-products generated in the reduction unit 2100 are recycled. Accordingly, the cost required to manufacture reduced iron can be reduced.

In the above, it was explained that the hydrogen gas supply unit 2200 is provided to produce hydrogen gas by post-processing or reforming the by-products discharged from the reduction unit 2100 and supply it to the reduction unit 2100. However, the hydrogen gas supply unit 2200 may be configured to supply separately prepared hydrogen gas to the reduction unit 2100 without recycling the by-products discharged from the reduction unit 2100. In this case, the hydrogen gas supply unit 2200 includes a reservoir in which hydrogen gas is stored, a supply pipe 2230 connecting the reservoir and the reduction unit, and a heater 2240 installed on the extension path of the supply pipe 2230 to heat the hydrogen gas. It can be provided.

In this way, the process of producing reduced iron by reducing iron ore using hydrogen gas, and producing molten iron by melting the reduced iron, may be a process called 'hydrogen reduction iron making process'. In the hydrogen reduction steelmaking process, hydrogen gas is supplied to the reduction unit 2100 to reduce raw materials, and the hydrogen gas reacts with iron ore to generate water or steam and does not generate carbon dioxide. Therefore, when hydrogen gas is supplied to the reduction unit 2100 to reduce raw materials, there is an effect of reducing carbon emissions. That is, hydrogen reduction in which the raw material is reduced by supplying only hydrogen gas to the reduction unit 2100, or a gas mixed with the exhaust gas discharged from the dissolving device 3000 and hydrogen gas is supplied to the reduction unit 2100 to reduce the raw material. The steelmaking process has the effect of reducing carbon emissions compared to the process of reducing raw materials using only exhaust gas.

Of course, the embodiment is not only a hydrogen reduction steelmaking process in which only hydrogen gas is supplied to the reduction unit 2100, or a mixture of exhaust gas discharged from the dissolution device 3000 and hydrogen gas is supplied to the reduction unit 2100, but also a dissolution device ( It can also be applied to a general steelmaking process in which only the exhaust gas discharged from 3000) is supplied to the reduction unit 2100.

The reduction unit 2100 reduces raw materials to produce reduced iron. That is, the reduction unit 2100 receives raw materials including iron ore from the raw material supply device 1000 and reacts the iron ore with the reducing gas to produce reduced iron. Here, the reducing gas supplied to the reduction unit 2100 may include at least one of hydrogen gas supplied from the hydrogen gas supply unit 2200 and exhaust gas discharged from the dissolving device 3000.

Hereinafter, in explaining the reduction unit 2100, hydrogen gas provided from the hydrogen gas supply unit 2200 and supplied to the reduction unit 2100 and exhaust gas provided from the dissolving device 3000 and supplied to the reduction unit 2100 are used. It is collectively referred to as ‘reduction gas’.

The reduction unit 2100 may include a reduction furnace that produces reduced iron while flowing raw materials. Additionally, a single reduction reactor may be provided, but a plurality of reduction reactors may be provided to effectively reduce low-grade iron ore or powdered iron ore with low iron content. When a plurality of reduction furnaces are provided in this way, the reduction unit 2100 includes a plurality of raw material transfer pipes (2111a to 2111c) and a plurality of gas transfer pipes (2112a to 2112c) installed to connect between the plurality of reduction furnaces (2100a to 2100d). ) may include.

As described above, a plurality of reduction furnaces 2100a to 2100d may be provided. And the plurality of reduction furnaces 2100a to 2100d may be connected to each other to sequentially move raw materials as shown in FIG. 1. The number of reduction furnaces 2100a to 2100d is not particularly limited, but in order to sufficiently reduce the raw materials, the reduction unit 2100 includes four reduction furnaces (first to fourth reduction furnaces 2100a to 2100d). It can be provided. And when the reduction unit 2100 includes four reduction furnaces (2100a to 2100d), the reduction unit 2100 includes three raw material transfer pipes (2111a to 2111c) and three gas transfer pipes (2112a to 2112c). can do.

The raw material supply device 1000 and the exhaust pipe 2210 of the hydrogen gas supply unit 2200 may be connected to the first reduction furnace 2100a among the first to fourth reduction furnaces 2100a to 2100d. That is, the raw material supply device 1000 is installed to be connected to the first reduction furnace 2100a, and the raw material discharged from the raw material supply device 1000 is charged into the first reduction furnace 2100a. And, the exhaust pipe 2210 of the hydrogen gas supply unit 2200 is connected to the first reduction furnace 2100a. Accordingly, by-products discharged from the first reduction reactor 2100a are discharged through the exhaust pipe 2210.

At least one of the supply pipe 2230 of the hydrogen gas supply unit 2200 and the exhaust gas supply line 4000 is connected to the fourth reduction furnace 2100d among the first to fourth reduction reactors 2100a to 2100d. Accordingly, the hydrogen gas extracted from the extractor 2220 can be supplied to the fourth reduction furnace (2100d) through the supply pipe 2230, and the exhaust gas of the dissolving device 3000 may be supplied to the fourth reduction furnace through the exhaust gas supply line 4000. It can be supplied to the furnace (2100d).

Raw material transfer pipes 2111a to 2111c are installed to connect the first to fourth reduction furnaces 2100a to 2100d. That is, the first raw material transfer pipe 2111a is between the first reduction reactor (2100a) and the second reduction reactor (2100b), and the second raw material transfer pipe is between the second reduction reactor (2100b) and the third reduction reactor (2100c). (2111b), a third raw material transfer pipe 2111c is installed between the third reduction furnace 2100c and the fourth reduction furnace 2100d. Accordingly, the raw material supplied to the first reduction furnace (2100a) and subjected to primary reduction is supplied to the second reduction furnace (2100b) through the first raw material transfer pipe (2111a), and is secondarily reduced in the second reduction furnace (2100b). The raw materials are supplied to the third reduction furnace (2100c) through the second raw material transfer pipe (2111b), and the raw materials tertiary reduced in the third reduction furnace (2100c) are supplied to the fourth reduction furnace through the third raw material transfer pipe (2111c). It is supplied to the furnace (2100d). And the fourth reduction raw material, that is, reduced iron, in the fourth reduction reactor (2100d) is supplied to the dissolution device (3000).

Gas transfer pipes 2112a to 2112c are installed to connect the first to fourth reduction furnaces 2100a to 2100d. That is, the first gas transfer pipe 2112a is between the fourth reduction reactor (2100d) and the third reduction reactor (2100c), and the second gas transfer pipe is between the third reduction reactor (2100c) and the second reduction reactor (2100b). (2112b), a third raw material transfer pipe 2111c is installed between the second reduction furnace 2100b and the first reduction furnace 2100a. Accordingly, the reducing gas supplied to the fourth reduction reactor (2100d) is sequentially transferred to the second to fourth reduction reactors (2100a to 2100d) through the first to third gas transfer pipes (2112a to 2112b). That is, the reducing gas supplied to the fourth reduction reactor (2100d) is supplied to the third reduction reactor (2100c) through the first gas transfer pipe (2112a), and the reducing gas supplied to the third reduction reactor (2100c) is supplied to the third reduction reactor (2100c). It is supplied to the second reduction furnace (2100b) through the second gas transfer pipe (2112b), and the reduction gas supplied to the second reduction furnace (2100b) is supplied to the first reduction furnace (2100a) through the third gas transfer pipe (2112c). is supplied as At this time, the gas supplied to the third reduction reactor (2100c), the second reduction reactor (2100b), and the first reduction reactor (2100a) through the first to third gas transfer pipes (2112a to 2112c) is supplied to the fourth reduction reactor (2100d). ), as well as the gas generated during the reduction reaction in each reduction furnace.

Figure 2 is a diagram showing a reduction furnace according to an embodiment of the present invention. Figure 3 is an enlarged cross-sectional view of a portion of the reduction furnace.

Referring to FIGS. 1 and 2, each of the first to fourth reduction furnaces 2100a to 2100d includes a container 2110 having an internal space (reduction space) that can accommodate raw materials and reduce the raw materials, and a reducing gas. It is provided with a plurality of holes 2122 through which can pass, and may include a dispersion member 2120 installed inside the container 2110. In addition, at least a portion of the container 2110 may further include a cyclone 2140 installed to collect fine powder.

In addition, some of the first to fourth reduction furnaces 2100a to 2100d may include a burner 2130 that generates a flame. At this time, the burner 2130 is preferably provided in reduction furnaces located at both ends of the first to fourth reduction furnaces 2100a to 2100d, that is, in reduction furnaces other than the first and fourth reduction furnaces 2100a and 2100d, For example, a burner 2130 may be provided in at least one of the second and third reduction furnaces 2100b and 2100c. Of course, all of the first to fourth reduction furnaces 2100a to 2100d may be provided with a burner 2130. Additionally, at least one of the first and fourth reduction furnaces 2100a and 2100d disposed at both ends may be provided with a burner 2130.

Hereinafter, as shown in FIG. 1 , the second and third reduction furnaces 2100b and 2100c among the first to fourth reduction furnaces 2100a to 2100d will be described as an example of having a burner 2130. Here, the second reduction reactor (2100b) and the third reduction reactor (2100c) have the same configuration, and the second and third reduction reactors (2100b, 2100c) are compared with the first and fourth reduction reactors (2100a to 2100d). Therefore, there is a difference in that an additional burner 2130 is provided.

Therefore, the reduction furnace will be described below, and then the second reduction furnace 2100b, which is one of the reduction furnaces equipped with a burner, will be described as an example with reference to FIGS. 2 and 3. And description of the first reduction reactor 2100a and the third and fourth reduction reactors 2100c and 2100d will be omitted. And the second reduction reactor 2100b described below may be simply named 'reduction reactor 2100b'.

Referring to FIGS. 2 and 3, the reduction furnace 2100b includes a container 2110 having an internal space (reduction space) that can accommodate raw materials and reduce the raw materials, and a plurality of holes through which reducing gas can pass. (2122), a dispersion member 2120 installed inside the container 2110, and a burner 2130 installed in the container 2110 to be located on the upper side of the dispersion member 2120 to generate a flame inside the container 2110. ) may include. In addition, the reduction furnace 2100b may further include a cyclone 2140 that is at least partially installed inside the container 2110 to collect fine powder.

The dispersion member 2120 includes a plate-shaped body 2121 having a predetermined area and a plurality of holes 2122 provided in the body 2121 to allow gas to pass through. For example, the dispersion member 2120 may be a plate-shaped perforated plate. This dispersion member 2120 is installed inside the container 2110 to divide the internal space of the container 2110 in the vertical direction. At this time, the dispersion member 2120 is preferably installed closer to the lower wall of the container 2110 than the upper wall. Accordingly, the internal space of the container 2110 may be divided into a space below the dispersion member 2120 and a space above the dispersion member 2120.

In addition, a gas transfer pipe 2112b may be connected to the lower part of the container 2110 to communicate with the lower space of the dispersion member 2120, and a raw material transfer pipe 2111a may be connected to communicate with the upper space of the dispersion member 2120. there is. Accordingly, the reducing gas is supplied to the space below the dispersion member 2120 in the internal space of the container 2110, and the raw material is supplied to the space above the dispersion member 2120. At this time, the raw materials supplied into the container 2110 are loaded on the top of the dispersion member 2120. The reducing gas supplied to the lower space of the dispersion member 2120 passes through the plurality of holes 2122 of the dispersion member 2120 and moves or is injected to the upper side of the dispersion member 2120. And the raw material on the upper side of the dispersing member 2120 flows by the reducing gas injected toward the upper side of the dispersing member 2120. That is, the raw material particles on the upper side of the dispersion member 2120 flow due to the upward flow of the reducing gas passing through the plurality of holes 2122 of the dispersion member 2120. Then, the raw material flows above the dispersion member 2120 and reacts with the reducing gas to be reduced.

In the reduction furnace 2100b, a reduction reaction occurs between the hydrogen gas supplied from the hydrogen gas supply unit 2200 and at least one of the exhaust gas exhausted from the dissolving device 3000 and supplied from the exhaust gas supply line 4000 and the raw material including iron ore. . At this time, the reaction between iron ore and hydrogen gas and the reaction between iron ore and carbon monoxide (CO) contained in the exhaust gas are endothermic reactions. Accordingly, the temperature inside the reduction furnace 2100b may decrease due to the endothermic reaction, which becomes a factor in reducing the reduction rate of the raw material. Therefore, for a smooth reduction reaction, it is necessary to adjust the temperature inside the reduction furnace 2100b to a predetermined temperature or higher. Therefore, the burner 2130 is installed in the container 2110 to generate a flame (F) to heat the inside of the container 2110. The burner 2130 may be a means of blowing an oxidizing agent containing oxygen (O) into the container 2110 to generate a flame (F) through a combustion reaction. The specific structure and shape of the burner 2130 will be described later.

Meanwhile, the closer the distance between the burner 2130 and the dispersion member 2120, the higher the temperature of the dispersion member 2120. This is because the closer the distance between the burner 2130 and the dispersion member 2120 is, the closer the distance between the flame F generated from the burner 2130 and the dispersion member 2120 is. In this case, the raw material particles are melted by the high heat of the dispersion member 2120 and become entangled with each other, which may block the hole 2122 of the dispersion member 2120. If the hole 2122 is blocked, the reducing gas cannot pass through, so there is a problem in that the raw material does not flow smoothly on the upper side of the dispersion member 2120. And if the flow of raw materials is not smooth, the reduction rate of the raw materials decreases.

Therefore, in the embodiment, the separation distance between the dispersion member 2120 and the burner 2130 is optimized. In other words, the burner 2130 is installed at an optimized height. At this time, the burner 2130 is installed to be located above the dispersion member 2120. Accordingly, the separation distance between the dispersion member 2120 and the burner 2130 is defined as 'height of the burner 2130' or 'installation height of the burner 2130'.

When installing the burner 2130 in the container 2110, the installation height is first determined, and the burner 2130 is installed at the determined height. At this time, the height at which the burner 2130 is to be installed (hereinafter referred to as installation height (H _b )) may be determined according to the flow rate of the reducing gas to be supplied to the reduction furnace 2100b. To be more specific, the installation height (H _b ) of the burner 2130 is determined by the diameter (d _or ) of the hole 2122 of the dispersion member 2120 and the flow rate (m/sec) of the reducing gas supplied to the reduction furnace (2100b). ) can be determined by the flow rate of the reducing gas determined by .

Hereinafter, a method for determining the installation height (H _b ) of the burner will be described in more detail.

In determining the height (H _b ) at which the burner 2130 will be installed, the flow rate of the reducing gas to be supplied to the reduction furnace 2100b is used to determine the depth at which the reducing gas penetrates into the raw material layer on the upper side of the dispersion member 2120 ( l _j ) is calculated. Then, the height (H _b ) at which the burner 2130 will be installed is determined using the calculated penetration depth (l _j ).

First, the depth at which the reducing gas penetrates into the raw material layer will be described using FIGS. 2 and 3. Raw materials including iron ore are supplied into the container 2110 of the reduction furnace 2100b, as shown in FIG. 3, and are loaded on the upper side of the dispersion member 2120. Accordingly, the raw materials are piled up to a predetermined thickness on the upper side of the dispersion member 2120. Hereinafter, the raw material piled up to a predetermined thickness on the upper side of the dispersing member 2120 is referred to as a 'raw material layer'. And, since the raw material on the upper side of the dispersion member 2120 flows in the reducing gas injected from the lower side, the raw material layer may mean a fluidized layer.

The reducing gas supplied to the lower side of the dispersion member 2120 passes through the plurality of holes 2122 of the dispersion member 2120 and is injected to the upper side where the raw material layer is located. Accordingly, the reducing gas penetrates into the raw material layer above the dispersion member 2120. At this time, the reducing gas is injected upward from the upper surface of the dispersion member 2120 up to a predetermined distance. That is, the reducing gas penetrates into the raw material layer above the dispersion member 2120, and penetrates to a predetermined depth. Here, the penetration depth (l _j ) of the reducing gas is based on the upper surface of the dispersion member 2120.

In order to derive or predict the depth l _j at which the reducing gas penetrates into the raw material layer, first, the flow rate of the reducing gas to be supplied to the reducing furnace 2100b, that is, the container 2110, is determined. In other words, determine the target flow rate of reducing gas to be supplied to the container. Here, the target flow rate of the reducing gas may be determined by at least one of the amount of raw material to be supplied to the reducing furnace (2100b), the volume of the container 2110 of the reducing furnace (2100b), and the target reduction rate.

The flow rate of the reducing gas supplied to the reduction furnace 2100b varies depending on at least one of the diameter of the hole 2122 of the dispersion member 2120 and the flow rate of the reducing gas supplied to the reduction furnace. For example, when reducing gas is supplied at a predetermined target flow rate, the larger the flow rate of reducing gas (u _or ), the diameter (d _or ) of the hole 2122 decreases, and the flow rate of reducing gas (u _or ) decreases. As this becomes smaller, the flow rate of the reducing gas can be adjusted by increasing the hole diameter (d _or ).

Accordingly, when the flow rate of the reducing gas to be supplied to the reduction furnace 2100b is determined, the reducing gas to be supplied to the container 2110 is determined using the determined flow rate of the reducing gas and the diameter (d _or ) of the hole provided in the dispersing member 2120. Determine the flow rate (u _or ).

Once the flow rate (u _or ) of the reducing gas is determined, the depth (l _j ) at which the reducing gas penetrates into the raw material layer is predicted using this. To be more specific, the depth l _j at which the reducing gas penetrates into the raw material layer may vary depending on the flow rate of the reducing gas supplied to the container 2110. That is, the penetration depth (l _j ) of the reducing gas may be determined depending on the diameter (d _or ) of the hole 2122 of the dispersion member 2120 and the flow rate (u _or ) of the reducing gas supplied to the reduction furnace (2100b). . More specifically, the penetration depth (l _j ) of the reducing gas is, in addition to the diameter (d _or ) of the hole 2122 of the dispersion member 2120 and the flow rate (u _or ) of the reducing gas, the density (ρ _g ) of the reducing gas, It can be determined by the dynamic viscosity of the gas (μ), the particle density of the raw material (ρ _s ), and the particle diameter of the raw material (d _p ).

More specifically, the diameter of the hole 2122 of the dispersion member 2120 (d _or ), the flow rate of the reducing gas (u _or ), the density of the reducing gas (ρ _g ), the dynamic viscosity of the reducing gas (μ), and the raw material. The depth (l _j ) through which the reducing gas penetrates into the raw material layer can be calculated by calculating the particle density (ρ _s ) and the particle diameter (d _p ) of the raw material by applying Equation 1 below.

[Equation 1]

l _j : penetration depth (m)

d _or : diameter of dispersion member hole (mm)

u _or : flow rate of reducing gas (m/sec)

g: acceleration of gravity

ρ _g : Density of reducing gas (kg/m ³ )

ρ _s : Particle density of raw material (kg/m ³ )

d _p : particle diameter of raw material (mm)

μ: Dynamic viscosity of reducing gas (N·sec/㎡)

Here, the density of the reducing gas (ρ _g ) and the dynamic viscosity (μ) of the reducing gas are determined depending on the reducing gas used and are known values. That is, as the reducing gas supplied to the reduction furnace 2100b, at least one of the hydrogen gas provided from the hydrogen gas supply unit 2200 and the exhaust gas provided from the dissolving device 3000 is used, so the density of these gases (ρ _g ) and dynamic viscosity (μ) are applied.

In addition, the particle density (ρ _s ) of the raw material and the particle diameter (d _p ) of the raw material are determined depending on the raw material supplied to the reduction furnace 2100b for producing reduced iron, and are known values. That is, the particle density (ρ _s ) and particle diameter (d _p ), which are physical properties of the raw material to be supplied to the reduction furnace (2100b), are determined and applied.

Calculating and calculating the penetration depth (l _j ) of the reducing gas in this way is, in other words, predicting the depth (l _j ) at which the reducing gas supplied to the reduction furnace (2100b) penetrates into the raw material layer during the reduced iron manufacturing process. It may be.

When the depth (l _j ) at which the reducing gas penetrates into the raw material layer is calculated using Equation 1, the height (H _b ) at which the burner 2130 will be installed is determined using the calculated penetration depth (l _j ). At this time, the installation height (H _b ) is determined to be greater than or equal to the calculated penetration depth (l _j ) and less than or equal to the height of the raw material layer (H _m ) (see relational equation 1). Here, the height (H _m ) of the raw material layer may be the distance from the upper surface of the dispersion member 2120 to the upper surface of the raw material layer. And the height (H _m ) of this raw material layer may be the height (H _m ) of the upper surface of the raw material layer before supplying the reducing gas to the reduction furnace 2100b and before the raw material flows.

[Relational Expression 1]

l _j ≤ H _b ≤ H _m

Hereinafter, a method for determining the installation height (H _b ) of the burner 2130 will be described using a more specific example. Assuming that the calculated penetration depth (l _j ) is 580 mm and the height of the raw material layer is 650 mm when the raw materials are supplied to the reduction furnace, the installation height (H _b ) of the burner 2130 is 580 mm to 650 mm ( It can be determined in the range of 580 mm or more and 650 mm or less. For example, the installation height (H _b ) of the burner can be determined to be 600 mm.

In determining the installation height (H _b ) of the burner 2130, it is determined in the range of the calculated penetration depth (l _j ) or less than the height of the raw material layer (H _m ), so that the 'penetration depth (l _j ) or more raw material The range below the floor height (H _m ) can be named ‘installation height condition’.

Once the installation height (H _b ) is determined, the burner 2130 is installed at the determined installation height (H _b ). That is, the burner 2130 is installed so that the separation distance from the dispersion member 2120 is the determined installation height (H _b ). In other words, the burner 2130 is installed on the upper side of the dispersion member 2120 so that the separation distance from the upper surface of the dispersion member 2120 is the determined installation height (H _b ) value. At this time, it is preferable to install the burner 2130 so that the separation distance between the radial center of the burner 2130 and the upper surface of the dispersion member 2120 is the determined installation height (H _b ) value.

Meanwhile, if the installation height (H _b ) of the burner 2130 is too low and the separation distance between the burner 2130 and the dispersing member 2120 is too close, the flow of raw materials may not be smooth and may stagnate. That is, a stagnation layer can be formed, and the stagnation layer can be formed thick. This is because the closer the distance between the burner 2130 and the dispersion member 2120 is, the closer the distance between the flame F generated from the burner 2130 and the dispersion member 2120 is. Conversely, if the installation height (H _b ) of the burner 2130 is too high and the separation distance between the burner 2130 and the dispersing member 2120 is too long, the reduction reaction of the raw material may not be smooth. That is, in the case of raw materials located close to the dispersing member 2120, the temperature is low and reaction with the reducing gas may not occur or may not occur sufficiently. To explain this in other words, the temperature of the raw material particles flowing on the upper side of the dispersion member 2120, that is, the fluidized bed, is low, so the reduction reaction may not sufficiently occur.

However, in the embodiment, the installation height (H _b ) is determined by the above-described method, and the burner 2130 is installed at the determined installation height (H _b ). Due to this, the raw materials can be sufficiently reduced while allowing them to flow smoothly without stagnation. In other words, the dispersion member 2120 is suppressed or prevented from being heated to a high temperature by the heat of the flame F generated by the burner 2130, so that the raw material particles melt and stick together at a location close to the dispersion member 2120. Alternatively, aggregation can be suppressed and prevented. Accordingly, it is possible to suppress or prevent the raw material particles from not flowing or stagnating with little flow on the upper side of the dispersing member 2120 due to the heat of the dispersing member 2120. In other words, it is possible to suppress or prevent the formation of a stagnation layer in which raw material particles do not flow or are gathered together in a state in which the flow is suppressed. Additionally, sufficient heat can be applied to the raw materials and reducing gas to ensure that the reduction reaction occurs smoothly.

Therefore, the installation height (H _b ) of the burner 2130 determined by the method according to the embodiment can be explained as a height that can sufficiently reduce the raw material while suppressing or preventing the formation of the entire layer.

Figure 4 is a front cross-sectional view of a burner according to an embodiment of the present invention. Figure 5 is a plan view of a burner according to an embodiment of the present invention. Figure 6 is a diagram explaining the flow of oxidant sprayed from a burner according to an embodiment of the present invention.

The burner 2130 includes a main body 2131 extending in one direction, and a plurality of nozzles 2132a and 2132b, each of which is extended in an extension direction of the main body 2131 and installed inside the main body 2131.

The main body 2131 may be provided in a circular or cylindrical shape as shown in FIG. 5. Of course, the shape of the main body 2131 is not limited to this, and it may be of any shape as long as at least a portion of it can be installed to be inserted into the container 2110 and a plurality of nozzles 2132a and 2132b can be installed therein. .

As described above, a plurality of nozzles 2132a and 2132b may be provided. For example, two nozzles (first and second nozzles 2132a and 2132b) may be provided. Each of the first and second nozzles 2132a and 2132b extends in the federal direction of the main body 2131 and has an internal space through which the oxidizing agent can pass. And, in each of the first and second nozzles 2132a and 2132b, one end and the other end, which are both ends in the extending direction, are open. Each of the first nozzle 2132a and the second nozzle 2132b may have an inner diameter of, for example, 15 mm to 20 mm, and more specifically, 16 mm to 19 mm. Of course, the inner diameters of each of the first and second nozzles 2132a and 2132b may be changed in various ways.

One end of each of the first and second nozzles 2132a and 2132b is an opening (hereinafter referred to as an injection port) through which the oxidizing agent is discharged or sprayed outward. Additionally, the other ends of each of the first and second nozzles 2132a and 2132b are openings (hereinafter referred to as inlets) through which the oxidizing agent flows into the first and second nozzles 2132a and 2132b. Here, an oxidizing agent supply unit (not shown) may be connected to the other end of each of the first and second nozzles 2132a and 2132b. The oxidizing agent supply unit may include a reservoir in which the oxidizing agent is stored, a supply pipe connected to the first and second nozzles 2132a and 2132b to supply the oxidizing agent, and a regulator installed in the supply pipe to control at least one of the supply flow rate and flow rate of the oxidizing agent. You can.

The oxidizing agent contains oxygen (O), and the oxygen (O) content of the entire oxidizing agent may be 50 wt% or more and less than 100 wt%. Additionally, the oxidizing agent further contains non-oxidizing substances in addition to oxygen (O), and the content of non-oxidizing substances in the total oxidizing agent may be greater than 0 wt% and less than 50 wt%. And, the non-oxidizing material may include nitrogen (N ₂ ). That is, the oxidizing agent may include oxygen (O) and nitrogen (N ₂ ), and the content of oxygen (O) in the total oxidizing agent is 50 wt% or more and less than 100 wt%, and the content of nitrogen (N ₂ ) is 0 wt. % may be greater than 50 wt%.

In this way, the oxidizing agent is not made of 100% oxygen (O) and is prepared to contain more non-oxidizing substances in addition to oxygen (O) in order to lower the temperature of the flame generated when the oxidizing agent is burned inside the reduction furnace (2100b). am. That is, if the oxidizing agent consists of 100% oxygen (O), the temperature of the flame formed inside the reduction furnace 2100b due to the combustion reaction of the oxidizing agent is too high, so a stagnant layer may be formed, and a thick stagnant layer may form. can be formed.

And when spraying the oxidizing agent from each of the first nozzle 2132a and the second nozzle 2132b, it is preferable to adjust the flow rate to 80 m/sec to 100 m/sec.

The first nozzle 2132a and the second nozzle 2132b are not arranged side by side but intersect each other. At this time, each of the first and second nozzles 2132a and 2132b may be provided to become closer to the radial center of the main body 2131 from the other end to one end. To explain this in other words, the distance between the first nozzle 2132a and the second nozzle 2132b may become closer from the other end to the one end.

In other words, the first and second nozzles 2132a and 2132b may be inclined or provided to be slanted. To explain this in more detail, an imaginary line connecting the radial center of one end of the main body 2131 and the center of the direct hit direction of the other end is defined as the 'baseline (L _c )'. And the virtual line connecting one end and the other end of the first nozzle 2132a is called 'first nozzle extension line (L _n1 )', and the virtual line connecting one end and the other end of the second nozzle 2132b is called 'second nozzle extension line ( It is defined as ‘L _n2 )’. In preparing the first and second nozzles 2132a and 2132b, the first and second nozzle extension lines L _n1 and L _n2 are provided to intersect the reference line L _c rather than being parallel to it. In addition, each of the first and second nozzles 2132a and 2132b is provided such that the angles θ ₁ and θ ₂ formed between the first and second nozzle extension lines L _n1 and L _n2 and the reference line L _c are acute angles. do. More specifically, the first and second nozzles (2132a, 2132b) each have an angle (θ ₁ , θ ₂ ) between the first and second nozzle extension lines (L _n1 , L _n2 ) and the reference line (L _c ) of 20°. It is prepared to be at an angle of 45°. Additionally, the first nozzle 2132a and the second nozzle 2132b may be provided symmetrically with respect to the reference line L _c .

In this way, each of the first and second nozzles (2132a, 2132b) is provided to intersect the reference line (L _c ) rather than being parallel to it, so that the first and second nozzles (2132a, 2132b) are inclined with respect to the reference line (L _c ) It can be explained as prepared. Additionally, the first nozzle 2132a and the second nozzle 2132b are not arranged side by side but intersect each other. Accordingly, the first nozzle 2132a may be described as being inclined with respect to the second nozzle 2132b, and the second nozzle 2132b may be described as being provided inclined with respect to the first nozzle 2132a.

The first and second nozzles (2132a, 2132b) are inclined so that the separation distance becomes closer toward one end of the main body to collide and spread the oxidant sprayed from each of the first and second nozzles (2132a, 2132b). am. Referring to FIG. 6 , the oxidizing agents OM ₁ and OM ₂ discharged from the injection ports of each of the first and second nozzles 2132a and 2132b are sprayed forward of the injection ports. At this time, the oxidizing agent (OM ₁ , OM ₂ ) moves to have a flow that gets closer to the radial center of the burner 2130 as it moves away from the injection nozzle. Accordingly, the oxidizing agent injected from the first nozzle 2132a and the oxidizing agent injected from the second nozzle 2132b collide at a point spaced a predetermined distance forward from one end of the burner 2130. After the oxidant sprayed from each of the first and second nozzles 2132a and 2132b collides, the oxidant spreads widely.

The oxidant sprayed from each of the first and second nozzles is sprayed in a stream shape with a predetermined width. Accordingly, the flow of a certain width formed by the oxidant sprayed from each of the first and second nozzles is defined as an 'oxidant stream'. Reflecting this and explaining the collision again, the oxidizing agent stream generated from the first nozzle 2132a and the oxidizing agent stream generated from the second nozzle 2132b collide in front of the burner. And after the plurality of oxidant streams collide, the oxidant streams spread as shown in FIG. 6. That is, multiple oxidant streams collide and combine to form one stream and spread widely. Therefore, the width of the oxidant stream widens after the collision.

When the oxidizing agent is injected from the burner 2130 into the container 2110, the oxidizing agent and the gas inside the container 2110 undergo a combustion reaction inside the container 2110, thereby generating a flame. That is, at least one of CO, H ₂ , and CH ₄ contained in the reducing gas supplied into the container 2110 and oxygen (O) among the oxidizing agents undergo a combustion reaction, and at this time, a flame is generated. And the inside of the container 2110 is heated by the heat of the flame.

The width W _F of the flame F may vary depending on the width of the oxidant stream injected from the nozzles 2132a and 2132b. That is, the smaller the width of the oxidant stream, the smaller the width (W _F ) of the flame (F), and the larger the width of the oxidant stream, the larger the width (W _F ) of the flame (F). In addition, when the oxidizing agent is sprayed at the same flow rate, the narrower the width (WF) of the flame ( _F ), the higher the flame temperature, and the wider the width (WF) of the flame ( _F ), the lower the flame temperature. This is because the narrower the width W _F of the flame F, the greater the amount of oxidizing agent contained in the flame F, and as the combustion reaction occurs in a narrow range, heat is concentrated. On the other hand, the larger the width (W _F ) of the flame (F), the smaller the amount of oxidizing agent contained in the flame (F), and as the combustion reaction occurs over a wider range, the heat is not concentrated but spreads widely, resulting in the temperature of the flame. is low.

Here, the temperature of the flame (F) may mean the highest temperature in the flame (F) having a predetermined width (W _F ). And the flame (F) has the highest temperature at the center of the width direction. Accordingly, the temperature of the flame F refers to the temperature at the center of the width direction. In addition, a low temperature of the flame (F) means that the maximum temperature at the center of the width direction is relatively low, and a high temperature of the flame (F) means that the maximum temperature at the center of the width direction is relatively high. do.

Therefore, in the embodiment, in order to form a flame at a lower temperature than before, a burner capable of forming a flame with a wider width than before was provided. That is, a porous burner 2130 is provided that can spread the oxidant widely by colliding with the injected oxidant. In other words, as described above, a plurality of nozzles (2132a, 2132b) are provided, each capable of spraying an oxidizing agent, and each nozzle (2132a, 2132b) increases in diameter of the main body (2131) toward one end of the main body (2131). It is tilted so that it approaches the center of direction. Accordingly, the oxidant streams sprayed from each of the plurality of nozzles 2132a and 2132b collide, causing the oxidant streams to spread widely. Therefore, as the combustion reaction occurs in the oxidant stream having a wide width, a wide flame can be formed. And accordingly, the temperature of the flame can be lowered compared to before. That is, compared to the flame generated from a conventional single-hole burner with one nozzle, the temperature of the flame generated from the multi-hole burner 2130 with a plurality of nozzles 2132a and 2132b as in the embodiment is lower.

Also, assuming that the burner 2130 is installed at the same height, the higher the temperature of the flame F generated from the burner 2130, the higher the temperature of the dispersion member 2120, so that the tablet layer is easily formed, and the purification layer is easily formed. The thickness of the layer may be thick. Conversely, the lower the temperature of the flame F generated from the burner 2130, the lower the temperature of the dispersion member 2120, making it difficult to form a purification layer, and even if a stagnation layer is formed, its thickness is thin. Accordingly, by generating a low temperature flame using the burner 2130 as in the embodiment, the formation of a stagnation layer on the upper side of the dispersion member 2120 can be suppressed or prevented. Accordingly, the raw materials on the upper side of the dispersion member 2120 can flow smoothly by the reducing gas, and thus the reduction rate of the raw materials can be improved. That is, the raw material charged into the reduction furnace 2100b can be sufficiently reduced.

In the above, it was explained that the burner 2130 has two nozzles 2132a and 2132b. However, it is not limited to this and the nozzles may be provided in various numbers exceeding two.

On the other hand, when the angles (θ ₁ , θ ₂ ) formed by each of the first nozzle 2132a and the second nozzle 2132b with the reference line L _c are less than 20° or more than 45°, collisions between oxidant streams do not occur. Otherwise, the amount of conflict may be insufficient. That is, when the inclined angle (θ ₁ , θ ₂ ) of at least one of the first nozzle 2132a and the second nozzle 2132b is less than 20° or exceeds 45°, the spray from the first nozzle 2132a The oxidizing agent stream and the oxidizing agent stream sprayed from the second nozzle 2132b may not collide, or the amount of collision may be small. In this case, the diffusion of the oxidant stream may be insufficient, so a narrow-width flame (F) may be formed, and accordingly, the temperature of the flame (F) may be high. Therefore, the angles (θ ₁ , θ ₂ ) of the first and second nozzles 2132a and 2132b are adjusted to 20° to 45°.

And by adjusting the angles (θ ₁ , θ ₂ ) of the first and second nozzles (2132a, 2132b) from 20° to 45°, the oxidant stream sprayed from the first and second nozzles (2132a, 2132b) is formed to be inclined. do. That is, the oxidant streams injected from the first and second nozzles 2132a and 2132b are formed in an inclined shape so that the farther away they are from one end of the main body 2131, the closer they are to the center of the diameter of the main body 2131.

When spraying the oxidizing agent from each of the first nozzle 2132a and the second nozzle 2132b, the flow rate of the oxidizing agent spraying from each nozzle 2132a and 2132b is adjusted to 80 m/s to 100 m/s. By adjusting the flow rate of the oxidant sprayed from the first and second nozzles (2132a, 2132b) to 80 m/s to 100 m/s, the oxidant streams sprayed from the first and second nozzles (2132a, 2132b) collide and diffuse. You can do it.

Meanwhile, when the flow rate of the oxidant sprayed from at least one of the first and second nozzles 2132a and 2132b is less than 80 m/s, the oxidant stream sprayed from the first nozzle 2132a and the oxidant sprayed from the second nozzle 2132b Streams may not collide, or the amount of collision may be small. Additionally, when the flow rate of the oxidant sprayed from at least one of the first and second nozzles 2132a and 2132b exceeds 100 m/s, the temperature of the flame is high, which may promote the formation of a stagnation layer. Therefore, it is desirable to adjust the flow rate of the oxidant sprayed from the first and second nozzles 2132a and 2132b to 80 m/s to 100 m/s.

Figure 7 is a diagram schematically showing an experimental reduction reactor. Figure 8 shows the results of measuring the temperature in the horizontal direction at a predetermined height of the experimental reduction furnace. Figure 9 shows the results of measuring the temperature of the area from the dispersion member to a predetermined height upward in the experimental reduction furnace.

Here, Figures 8 (a) and Figure 9 (a) show the results of an experiment when a burner (single-hole burner) with one nozzle was installed in an experimental reduction furnace to generate a flame. And Figures 8 (b) and Figure 9 (b) are the results of an experiment when a flame was generated by installing a burner (porous burner) with a plurality of nozzles according to the embodiment in the experimental reduction furnace. .

First, the experimental reduction reactor will be described with reference to FIG. 7. The experimental reduction reactor shown in FIG. 7 is similar in configuration to the actual reduction reactor shown in FIG. 2. That is, the experimental reduction furnace includes a container 21, a dispersion member 22 having a plurality of holes through which the reducing gas can pass, and a burner that generates a flame.

In the experiment to obtain the results shown in FIGS. 8 and 9, the experiment was conducted by installing a first type of burner with one nozzle in a container, and the experiment was performed by installing a second type of burner in the container. did. In conducting the experiment by installing each of the first type burner and the second type burner, the first type burner and the second type burner were installed at the same height. Accordingly, the first type of burner and the second type of burner will be described by referring to the same reference numeral '23a'.

First, an experiment using the first type of burner 23a will be described. A first type burner 23a is installed in the container. At this time, the installation height (H _b1 ) of the burner 23a was installed at a position 350 mm above the dispersion member 22 . Then, an oxidizing agent was supplied to the first type of burner 23a and a reducing gas was supplied into the container 21, thereby generating a flame inside the container 21. At this time, hydrogen gas was used as the reducing gas. Next, the temperature inside the container 21 was measured. At this time, the temperature was measured in the horizontal direction at the height (H _b1 ) (350 mm) where the first type of burner 23a is installed, and the results are shown in (a) of FIG. 8. Additionally, the temperature of a predetermined area was measured upward from the dispersion member 22, and the results are shown in (a) of FIG. 9.

Next, an experiment was conducted using the second type of burner 23a. At this time, the installation height (H _b1 ) of the second type burner (23a) was set to 350 mm, the same as the height (H _b1 ) of the first type burner (23a) described above. Then, an oxidizing agent was supplied to the second type of burner 23a and hydrogen gas, a reducing gas, was supplied into the container 21 to generate a flame inside the container 21. At this time, the flow rates of the supplied oxidizing agent and reducing gas were the same as in the experiment using the first type of burner 23a. Next, the temperature was measured in the horizontal direction at the height (H _b1 ) (350 mm) where the second type of burner 23a is installed, and the results are shown in (b) of FIG. 8. Additionally, the temperature of a predetermined area was measured upward from the dispersion member 2120, and the results are shown in (b) of FIG. 9.

Comparing (a) and (b) of FIG. 8, the width (W _F1 ) of the flame generated by the first type of burner 23a at the same position is greater than that of the flame generated by the second type of burner 23a. The width of the flame (W _F2 ) is wide. More specifically, when comparing the width of the flame at a position spaced apart from the first and second types of burners 23a by a first distance D ₁ in the horizontal direction, the flame width is compared by the first type of burner 23a. The width (W _F2 ) of the flame generated by the second type of burner 23a ((b) in FIG. 8) is wider than the width (W _F1 ) of the generated flame ((a) in FIG. 8). From this, it can be seen that when using the burner 2130 according to the embodiment, the width of the flame can be increased.

Comparing Figures 9 (a) and (b), the temperature of the dispersion member 22 is lower in Figure 9 (b) than in Figure 9 (a). To be more specific, the temperature of the dispersion member 22 located at a second distance D ₂ in the horizontal direction from the first type of burner 23a is as high as about 1500°C. On the other hand, the temperature of the dispersion member 22 located at a second distance D ₂ in the horizontal direction from the second type of burner 23a is as low as about 1100°C. From this, it can be seen that when using the burner 2130 according to the embodiment, the temperature of the dispersion member 2120 can be lowered.

Figure 10 shows a burner of the first type having one nozzle installed in the vessel of an experimental reduction furnace to generate a flame, and Figure 11 shows a burner of the second type having first and second nozzles in the vessel of the experimental reduction furnace. This is the result showing the temperature distribution by height inside the container when a burner is installed to generate a flame. Here, the second type of burner may be a burner according to the embodiment.

First, the experiment performed to obtain the results of FIG. 10 will be described with reference to FIG. 7.

For the experiment, two burners of the first type were prepared, and the two burners of the first type were installed in the container 21 at different heights. At this time, the first type of burner installed at a relatively low height is called the first burner 23a, and the first type of burner installed relatively high compared to the first burner 23a is called the second burner 23b. At this time, the first burner 23a was installed at a height (H _b1 ) spaced 350 mm upward from the dispersion member 22, and the second burner 23b was installed at a height (H b1) spaced 600 mm upward from the dispersion member 2120. It was installed located at H _b2 ). Then, an oxidizing agent was supplied to each of the first and second burners 23a and 23b of the first type, and a reducing gas was supplied into the container 21, thereby generating a flame inside the container 21. Here, hydrogen gas was used as the reducing gas. Next, the temperature inside the container 21 was measured. At this time, the temperature was measured in the horizontal direction at the height (H _b1 ) (350 mm) where the first type of first burner 23a is installed, and the results are shown in (a) of Figure 10. In addition, the temperature was measured in the horizontal direction at the height (600 mm) where the second burner 23b of the first type is installed, and the results are shown in (b) of FIG. 10. Then, the horizontal temperature was measured below the first and second burners 23a and 23b and at a height of 100 mm above the dispersion member 22, and the results are shown in Figure 10 (c).

An experiment was conducted to obtain the results shown in FIG. 11 using the same method. That is, for the experiment, two burners of the second type were prepared, and the two burners of the second type were installed in the container at different heights. At this time, the second type of burner installed at a relatively low height is called the first burner 23a, and the second type of burner installed relatively high compared to the first burner 23a is called the second burner 23b. In addition, the first burner 23a of the second type was installed at a height H _b1 spaced 350 mm upward from the dispersion member 22, and the second burner 23b of the second type was installed at the dispersion member 22. ) was installed at a height (H _b2 ) 600 mm above. Then, an oxidizing agent was supplied to each of the first and second burners 23a and 23b of the second type, and a reducing gas was supplied into the container 21, thereby generating a flame inside the container 21. Here, hydrogen gas was used as the reducing gas. Next, the temperature was measured in the horizontal direction at the height (H _b1 ) (350 mm) where the first burner 23a of the second type is installed, and the results are shown in (a) of FIG. 11. In addition, the temperature was measured in the horizontal direction at the height (H _b2 ) (600 mm) where the second type of second burner 23b is installed, and the results are shown in (b) of FIG. 11. Then, the horizontal temperature was measured below the first and second burners 23a and 23b and at a height of 100 mm above the dispersion member 22, and the results are shown in Figure 11 (c).

Looking at the temperature distribution in the horizontal direction with reference to (a) of FIG. 10, compared to the temperature of the second area (A ₂ ), which is the area facing the lower side of the second burner (23b) of the first type, The temperature of the first area A ₁ , which is the area at the height where the first burner 23a is installed, is high. On the contrary, looking at (b) of FIG. 10, compared to the temperature of the first area (A ₁ ), which is the area facing the upper side of the first type of first burner (23a), the temperature of the first type of second burner (23b) The temperature of the second area (A ₂ ), which is the area at the height where is installed, is high.

In addition, looking at the temperature distribution in the horizontal direction with reference to (a) of FIG. 11, similarly, compared to the temperature of the second area (A ₂ ), which is the area facing the upper side of the second type of second burner (23b), The temperature of the first area A ₁ , which is the area at the height where the two types of first burners 23a are installed, is high. Conversely, looking at (b) of FIG. 11, compared to the temperature of the first area (A ₁ ), which is the area facing the upper side of the second type of first burner (23a), the temperature of the second type of second burner (23b) The temperature of the second area (A ₂ ), which is the area at the height where is installed, is high.

From this, it can be seen that the closer it is to the burner in the vertical direction, the higher the temperature.

10(c) and 11(c) show the temperature distribution in the horizontal direction at a height where the first and second burners 23a and 23b are not installed and the separation distance from the dispersion member 2120 is close. This is the result of measurement. That is, the horizontal temperature distribution is below the first burner 23a, which has a relatively low height among the first and second burners 23a and 23b, and at a height spaced 100 mm upward from the dispersion member 22.

First, looking at (c) of FIG. 10, the temperature of the first area A ₁ facing the first burner 23a of the first type at a height spaced 100 mm upward from the dispersion member 22 is about 1723°C. (2000K) or higher. On the other hand, looking at (c) of FIG. 11, the temperature of the first area A ₁ facing the first burner 23a of the second type at a height spaced 100 mm upward from the dispersion member 22 is It is lower than the temperature of the first area (A ₁ ) in (c). That is, in (c) of FIG. 11, the temperature of the first area (A ₁ ) is as low as 1650°C or lower.

From this, it can be seen that when the second type burner is equipped with a plurality of nozzles and is equipped to collide the oxidizing agent, that is, the burner according to the embodiment is used, the temperature of the dispersion member and its surroundings can be lowered. Able to know. That is, it can be seen that the temperature at the same height can be lowered when using the burner according to the embodiment compared to when using the first type of burner (conventional burner) equipped with one nozzle. there is.

In the embodiments, the height (H _b ) of the burner 2130 is optimized and installed as described above. That is, the burner 2130 is installed at a location where the separation distance from the dispersion member 2120 is optimized. Accordingly, it is possible to suppress or prevent the dispersion member 2120 from being heated to a high temperature by the heat of the flame F generated from the burner 2130. Therefore, it is possible to prevent the raw material particles from melting and sticking together or agglomerating at a location close to the dispersion member 2120. Accordingly, it is possible to suppress or prevent the formation of a stagnant layer on the upper part of the dispersion member 2120, and thus the raw materials can flow smoothly inside the reduction furnace. Additionally, sufficient heat can be applied to the raw materials and reducing gas to ensure that the reduction reaction occurs smoothly.

And, by using the burner 2130 having a plurality of nozzles 2132a and 2132b, the temperature of the flame F can be lowered. That is, the burner 2130 according to the embodiment sprays the oxidizing agent using a plurality of nozzles 2132a and 2132b that are inclined to intersect each other, causing the oxidizing agent to collide and spread. Accordingly, the width of the oxidant stream injected in front of the burner 2130 can be increased, and thus a low-temperature flame F can be formed. Therefore, it is possible to prevent the dispersion member 2120 and the raw material from being heated to an excessively high temperature by a high-temperature flame. Accordingly, agglomeration due to melting of raw material particles can be suppressed, thereby suppressing or preventing the formation of a stagnation layer. Therefore, raw materials can flow smoothly inside the reduction furnace 2100b.

2100a to 2100d: 1st to 4th reduction reactors
2110: container 2120: dispersion member
2130: Burner 2132a: First nozzle
2132b: Second nozzle
H _b : Installation height of burner

Claims (16)

A container having an internal space capable of accommodating raw materials including iron ore and reducing gas;
a dispersing member installed inside the container and having a plurality of holes through which the reducing gas can pass; and
A reduction furnace including a burner installed on an upper side of the dispersion member at a height spaced apart from the dispersion member determined using the target flow rate of the reducing gas to be supplied into the container and capable of generating a flame inside the container. In claim 1,
The installation height of the burner is a height determined using at least one of the diameter of the hole provided in the dispersion member (d _or ) and the flow rate (u _or ) of the reducing gas, which are adjusted according to the target flow rate of the reducing gas. In claim 1,
A reduction furnace in which the height at which the burner is installed is greater than or equal to the depth (l _j ) at which the reducing gas penetrates into the raw material layer consisting of the raw material supplied to the upper side of the dispersion member, and is less than or equal to the upper height of the raw material layer. In claim 1,
The burner is,
a body extending in one direction; and
A reduction furnace that extends in the direction in which the main body extends and includes a plurality of nozzles installed inside the main body, with the distance between them becoming closer as they get closer to one end of the main body. In claim 4,
A reduction furnace in which each of the plurality of nozzles is inclined at an angle of 20° to 45°. In claim 4,
A reduction furnace in which the plurality of nozzles are provided symmetrically with respect to the radial center of the main body. A process of determining the installation height (H _b ) of the burner based on the dispersion member installed inside the container using the target flow rate of the reducing gas to be supplied to the container of the reduction furnace;
A process of installing a burner in the container such that the distance from the dispersion member to the upper side is the determined installation height (H _b );
A process of supplying raw materials including iron ore to the upper side of the dispersing member;
A process of passing a reducing gas through a hole of the dispersion member to flow the raw material on the upper side of the dispersion member;
A process of generating a flame inside the container using the burner; and
A method of producing reduced iron comprising a process of reducing the raw material by reacting the raw material with a reducing gas. In claim 7,
Before determining a height (H _b ) to install the burner, determining a target flow rate of the reducing gas; and
A method of producing reduced iron comprising: determining the flow rate (u _or ) of the reducing gas to be supplied to the container using the determined target flow rate of the reducing gas and the diameter (d _or ) of the hole provided in the dispersion member. In claim 8,
The process of determining the installation height (H _b ) of the burner is,
A process of predicting the depth (l _j ) at which the reducing gas penetrates into the raw material layer above the dispersion member using the diameter of the hole (d _or ) and the flow rate (u _or ) of the reducing gas; and
A method of producing reduced iron comprising: determining a height (H _b ) at which the burner will be installed at a height greater than or equal to the predicted penetration depth (l _j ). In claim 9,
The process of predicting the depth (l _j ) at which the reducing gas penetrates into the raw material layer includes the diameter of the hole (d _or ), the flow rate of the reducing gas (u _or ), the density of the reducing gas (ρ _g ), and the raw material particles. A method for producing reduced iron including the process of calculating the penetration depth (l _j ) of the reducing gas using the density (ρ _s ), the particle size of the raw material particles (d _p ), and the dynamic viscosity (μ) of the reducing gas. In claim 9,
A method of producing reduced iron comprising determining the height (H _b ) at which the burner is to be installed in a range that is greater than or equal to the predicted penetration depth (l _j ) and less than or equal to the upper height of the raw material layer. In claim 7,
The process of generating a flame inside the container using the burner is,
A process of supplying an oxidizing agent to each of a plurality of nozzles provided in the burner;
forming an oxidizing agent stream by spraying an oxidizing agent from each of the plurality of nozzles;
A process of colliding a plurality of the oxidant streams to spread the oxidant streams; and
A method of producing reduced iron comprising: reacting the oxidizing agent stream with the reducing gas to generate a flame. In claim 12,
The process of spraying an oxidizing agent from each of the plurality of nozzles is,
A method of producing reduced iron including a process of spraying the oxidant sprayed from each of the plurality of nozzles so that the oxidizing agent becomes closer to the radial center of the burner as the distance from the burner increases. In claim 12,
The oxidizing agent is a method of producing reduced iron containing oxygen (O) and nitrogen (N ₂ ). In claim 12,
A method of producing reduced iron comprising adjusting the flow rate of the oxidizing agent sprayed from each of the plurality of nozzles to 80 m/sec to 100 m/sec. The method of any one of claims 7 to 15,
The reducing gas is a method of producing reduced iron containing hydrogen (H ₂ ) gas.

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