KR20230166525A - Electric furnace injection system and electric furnace including same - Google Patents

Abstract

The present invention relates to an injection system for an electric furnace capable of injecting at least one of fuel, supersonic oxygen, and powdered carbon into the internal space of an operating electric furnace body through a single nozzle, and to an electric furnace including the same, which is a pipe open at both ends. A powder carbon injection nozzle that is formed in a shape and injects the powder carbon-containing transfer fluid into the internal space of the electric furnace body through an internal first injection passage, and the transfer fluid surrounds the powder carbon injection nozzle. A film-cooling fluid nozzle that sprays the film-cooling fluid flowing through a second spray-flow channel, which is formed in the shape of a pipe with a closed end at which it is sprayed, and has an annular cross-section on the inside, toward the first spray-flow channel. And, the supersonic oxygen is injected into the internal space of the electric furnace body through a third injection passage that is formed in the shape of a pipe with both ends open to surround the membrane cooling fluid nozzle and has a circular cross-section on the inside. The fuel is supplied to the internal space of the electric furnace body through a supersonic oxygen nozzle and a fourth injection passage formed in the shape of a pipe open at both ends to surround the supersonic oxygen nozzle and having an annular cross section on the inside. It may include a fuel nozzle for spraying.

Description

Electric furnace injection system and electric furnace including same}

The present invention relates to an electric furnace injection system and an electric furnace including the same, and more specifically, to an electric furnace capable of injecting at least one of fuel, supersonic oxygen, and powdered carbon into the internal space of the operating electric furnace main body with a single nozzle. relates to an injection system and an electric furnace including the same.

An electric furnace refers to a furnace that heats and melts metals or alloys using electrical energy. It is a device that melts scrap by charging scrap into the furnace and then generating arc-shaped current between the electrode and the scrap to heat it.

In such an electric furnace, the injection system is a facility to melt scrap and secure additional heat sources needed for the process. In the early stages of scrap melting, a combustion burner is used to inject chemical energy (fuel) to melt the scrap, and then an oxygen lance is used. This continuously cuts and melts the scrap. During the melting operation, slag is generated at the top of the molten steel, and at this time, powdered carbon can be blown in from the wall of the electric furnace for slag forming.

Conventionally, in order to implement an oxygen lance, combustion burner, and powder injection in a single nozzle, a structure was formed in which the oxygen lance and powder injection outlet were positioned independently and then fuel was injected from the surrounding annular hole. Additionally, the powder injection was formed as a structure consisting of a single pipe with a constant internal diameter.

However, structures such as conventional injection systems have a problem in that the injection positions of oxygen and fuel are non-uniform in combustion mode (the injection outlets are formed deviated), resulting in low mixing performance and low combustion efficiency. In addition, when transferring powder carbon in the powder injection mode, the powder carbon collides with the inner wall, causing erosion on the inner wall, which reduces durability.

The present invention is intended to solve various problems including the problems described above, and is formed in a structure in which the oxygen lance, combustion burner, and powder injection are injected from the same central axis from a single nozzle, and the powder injection structure can prevent erosion. The purpose of the present invention is to provide an injection system for an electric furnace having a structure capable of preventing powder carbon from colliding with the wall by injecting a high-speed jet from multi-holes on the wall, and an electric furnace including the same. However, these tasks are illustrative and do not limit the scope of the present invention.

According to one embodiment of the present invention, an injection system for an electric furnace is provided. The injection system of the electric furnace is inserted into one side of the electric furnace main body where an internal space for producing molten steel is formed by melting the iron source, and injects at least one of fuel, supersonic oxygen, and powdery carbon into the internal space of the electric furnace main body during operation. In the electric furnace injection system capable of injecting one or more of the two ends, the transfer fluid containing the powdered carbon is formed in the shape of a pipe with open ends, and the transport fluid containing the powdered carbon is injected into the electric furnace main body through a first injection passage inside. a powder carbon injection nozzle for spraying into the internal space; The film cooling fluid flowing through a second injection passage is formed in the shape of a pipe with a closed end at an end side through which the transfer fluid is sprayed to surround the powder carbon injection nozzle, and is formed to have a circular cross-section on the inside. a film cooling fluid nozzle that sprays toward the first injection passage; Supersonic injection of the supersonic oxygen into the internal space of the electric furnace body through a third injection passage formed in the shape of a pipe open at both ends to surround the membrane cooling fluid nozzle and having an annular cross section on the inside. oxygen nozzle; and a fuel nozzle that is formed in the shape of a pipe open at both ends to surround the supersonic oxygen nozzle and injects the fuel into the internal space of the electric furnace main body through a fourth injection passage formed to have an annular cross section on the inside. May include ;.

According to one embodiment of the present invention, the fuel nozzle is formed in a ring shape with a spiral groove so as to generate a swirl flow in the fuel passing through the fourth injection passage, and has an annular cross section. The branch may include a swirler inserted into the fourth injection passage.

According to one embodiment of the present invention, the powder carbon injection nozzle, the film cooling fluid nozzle, the supersonic oxygen nozzle, and the fuel nozzle may be coaxially formed to form a single nozzle assembly.

According to one embodiment of the present invention, the single nozzle assembly injects at least one of the fuel, the supersonic oxygen, and the powder carbon through the powder carbon injection nozzle, the supersonic oxygen nozzle, and the fuel nozzle. The powdered carbon injection nozzle and the injection port-side end of the supersonic oxygen nozzle are formed so that a mixing space in which at least one of the fuel, supersonic oxygen, and powdered carbon can be mixed is formed in the injection port portion. It may be formed inside the single nozzle assembly rather than the end of the fuel nozzle on the injection port side.

According to one embodiment of the present invention, the fuel nozzle is installed at at least a portion of an end on the injection port side so that the fuel injected through the fourth injection passage can be injected in a form that is collected toward the center of the mixing space. , the annular cross-section of the fourth injection passage may be formed to have a gradually smaller diameter toward the injection hole.

According to one embodiment of the present invention, the annular outer wall of the fuel nozzle, which is formed as the outermost wall of the single nozzle assembly, has a cooling passage through which a cooling medium flows so as to cool the single nozzle assembly. It can be.

According to one embodiment of the present invention, the powder carbon injection nozzle has an outer wall surface of the powder carbon injection nozzle so as to connect the first injection passage inside and the second injection passage of the film cooling fluid nozzle. A plurality of protective hole portions may be formed to penetrate between inner wall surfaces.

According to one embodiment of the present invention, the plurality of protection holes are configured to prevent the powder carbon passing through the first injection passage of the powder carbon injection nozzle by the transport fluid from colliding with the inner wall surface of the powder carbon injection nozzle. In order to prevent this, a plurality of powder carbon injection nozzles are formed at equal intervals along the circumferential direction and the longitudinal direction of the inner wall surface of the powder carbon injection nozzle, and are directed from the inner wall surface toward the central axis of the first injection passage. The membrane cooling fluid may be sprayed.

According to one embodiment of the present invention, the plurality of protection hole portions are configured such that the transfer fluid flowing through the first injection passage of the powder carbon injection nozzle increases from the outer wall surface of the powder carbon injection nozzle to the inner wall surface. It may be formed to be inclined toward the flow direction.

According to one embodiment of the present invention, the supersonic oxygen nozzle may be formed as a Laval nozzle to increase the flow rate of the supersonic oxygen passing through the third injection passage to more than the speed of sound.

According to one embodiment of the present invention, the supersonic oxygen nozzle is formed so that its cross-sectional area gradually decreases along the flow direction of the supersonic oxygen from the inlet into which the supersonic oxygen flows, so that the supersonic oxygen flowing inside is A compression unit that compresses; a neck portion formed with a minimum cross-sectional area to maximize compression of the supersonic oxygen compressed in the process of flowing the compression portion; and an expansion part that is formed to have a cross-sectional area that gradually increases along the flow direction of the supersonic oxygen from the neck to the injection part where the supersonic oxygen is sprayed, and expands the supersonic oxygen flowing therein.

According to one embodiment of the present invention, the compression section and the expansion section are formed along the central axis of the third injection passage so that the cross-sectional area of the annular cross-section changes to gradually become smaller or larger in a non-linear manner, thereby forming an overall streamlined shape. It may be formed by a combination of at least two or more curves, including a convex curve formed in a convex curve shape based on a reference and a concave curve formed in a concave curve shape based on the central axis of the third injection passage.

According to another embodiment of the present invention, an electric furnace is provided. The electric furnace includes an electric furnace main body in which an internal space is formed into which an iron source can be charged and dissolved; an electrode that is at least partially inserted into the interior space through the small ceiling of the loop portion on the upper side of the electric furnace main body to melt the iron source by arc heat so as to produce molten steel; and an injection system that is inserted into one side of the electric furnace main body and injects at least one of fuel, supersonic oxygen, and powdered carbon into the internal space of the electric furnace main body during operation, wherein the injection system is installed at both ends. a powder carbon injection nozzle that is formed in the shape of an open pipe and sprays the transfer fluid containing the powder carbon into the internal space of the electric furnace main body through an internal first injection passage; The film cooling fluid flowing through a second injection passage is formed in the shape of a pipe with a closed end at an end side through which the transfer fluid is sprayed to surround the powder carbon injection nozzle, and is formed to have a circular cross-section on the inside. a film cooling fluid nozzle that sprays toward the first injection passage; Supersonic injection of the supersonic oxygen into the internal space of the electric furnace body through a third injection passage formed in the shape of a pipe open at both ends to surround the membrane cooling fluid nozzle and having an annular cross section on the inside. oxygen nozzle; and a fuel nozzle that is formed in the shape of a pipe open at both ends to surround the supersonic oxygen nozzle and injects the fuel into the internal space of the electric furnace main body through a fourth injection passage formed to have an annular cross section on the inside. May include ;.

According to another embodiment of the present invention, the electric furnace main body includes a lower cell forming a lower side of the internal space; and an upper cell that is combined with the lower cell to form an upper side of the interior space and whose upper side is closed by the loop portion.

According to another embodiment of the present invention, the injection system is formed of a single nozzle assembly in which the powder carbon injection nozzle, the film cooling fluid nozzle, the supersonic oxygen nozzle, and the fuel nozzle are coaxially formed, It may be formed to penetrate the wall of the upper cell or the lower cell.

According to another embodiment of the present invention, the injection system may be formed to be inclined downward at a predetermined angle toward the lower side of the electric furnace main body.

According to an embodiment of the present invention as described above, a structure is formed so that the oxygen lance, combustion burner, and powder injection are injected from the same central axis from a single nozzle, thereby achieving the effect of increasing mixing ability, combustion efficiency, and injection efficiency. You can have it. In addition, it can prevent destruction of the inner wall of the powder transfer pipe due to the film cooling fluid, thereby increasing the replacement cycle and lifespan of the nozzle.

In addition, when using the powder injection mode, in the prior art, it was difficult to achieve a shroud effect because the central axes of the oxygen nozzle and the powder injection were different. However, by forming a structure so that the oxygen lance and the powder injection were injected from the same central axis from a single nozzle, the powder injection Even when using injection mode, effective powder injection through the shroud effect can be possible by supplying supersonic oxygen through an oxygen lance.

In this way, reflecting the electric furnace process, oxygen lance, combustion burner, and powder injection modes can be selectively utilized at each stage from a single nozzle in the early, middle, late, and refining stages of scrap melting, and in addition to supplying fluid for powder transfer, membrane cooling multi Additional fluid is supplied from the hole to increase the speed of the powder at the nozzle, which can have the advantage of inducing slag forming, and the shape of the supersonic nozzle for a shroud effect in the annular gap around the powder transfer pipe is applied to the supersonic characteristic curve to create a stable supersonic fluid. By supplying injection and high Mach number fluid, it is possible to implement an electric furnace injection system and an electric furnace including the same that can guide the powder carbon passing through the powder transfer pipe close to the upper surface of the slag without being disturbed by the surrounding environment. Of course, the scope of the present invention is not limited by this effect.

1 is a cross-sectional view schematically showing an electric furnace according to an embodiment of the present invention.
Figures 2 and 3 are perspective and cross-sectional views schematically showing the injection system installed in the electric furnace of Figure 1.
Figure 4 is an enlarged view showing part “A” of Figure 3.
Figure 5 is an enlarged view showing part “B” of Figure 4.
Figures 6 to 9 are cross-sectional views showing various injection modes of the injection system installed in the electric furnace of Figure 1, respectively.

Hereinafter, various preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art, and the following examples may be modified into various other forms, and the scope of the present invention is as follows. It is not limited to examples. Rather, these embodiments are provided to make the present disclosure more faithful and complete and to fully convey the spirit of the present invention to those skilled in the art. Additionally, the thickness and size of each layer in the drawings are exaggerated for convenience and clarity of explanation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will now be described with reference to drawings that schematically show ideal embodiments of the present invention. In the drawings, variations of the depicted shape may be expected, for example, depending on manufacturing technology and/or tolerances. Accordingly, embodiments of the present invention should not be construed as being limited to the specific shape of the area shown in this specification, but should include, for example, changes in shape resulting from manufacturing.

Figure 1 is a cross-sectional view schematically showing an electric furnace 1000 according to an embodiment of the present invention, and Figures 2 and 3 are a perspective view schematically showing the injection system 100 installed in the electric furnace 1000 of Figure 1 and It is a cross-sectional view, and FIG. 4 is an enlarged view showing part “A” of FIG. 3, and FIG. 5 is an enlarged view showing part “B” of FIG. 4. 6 to 9 are cross-sectional views each showing various injection modes of the injection system 100 installed in the electric furnace 1000 of FIG. 1.

First, as shown in FIG. 1, the electric furnace 1000 according to an embodiment of the present invention may largely include an injection system 100, an electric furnace main body 200, and an electrode 300. there is.

As shown in FIG. 1, the electric furnace main body 200 may be a type of furnace in which an internal space is formed in which an iron source such as scrap or directly reduced iron can be charged and dissolved.

For example, the electric furnace main body 200 is coupled to the lower cell 210 and the upper side of the lower cell 210 forming the lower side of the inner space, forming the upper side of the inner space, and the upper side is closed by the loop portion 230. It may be composed of an upper cell 220. At this time, although not shown, a fire-resistant wall constructed with fire-resistant glazing is formed on the inner wall of the lower cell 210 to protect the outer wall, and cooling water is circulated inside the inner wall of the upper cell 220 to protect the outer wall. Panel members may be mounted. In addition, although not shown, a raw material supply port for continuously supplying the iron source is formed on one side of the electric furnace main body 200, and a molten steel tapping port for continuously tapping the produced molten steel 1 is formed on the other side. You can.

In addition, the upper cell 220 may have a slag discharge door 221 formed at the lower end adjacent to the lower cell 210 to selectively allow the slag 2 formed on the upper side of the molten steel 1 to flow.

The loop portion 230 is seated on the top of the upper cell 220 and covers the open upper part of the upper cell 220, and a small ceiling is formed in the center to form an electrode 300 to be described later that generates arc heat. Can be installed penetratingly. Additionally, although not shown, the loop portion 230 may be connected to an exhaust pipe that discharges a large amount of waste gas and dust generated during the dissolution process of the iron source.

As shown in FIG. 1, the electrode 300 is formed of a plurality of electrode bundles, and at least a portion is inserted into the internal space through the small ceiling of the loop portion 230 on the upper side of the electric furnace main body 200. , the iron source can be melted by arc heat to produce molten steel (1).

As shown in FIG. 1, the injection system 100 is inserted into one side of the electric furnace main body 200 and injects fuel (F4 in FIG. 3) and supersonic oxygen into the internal space of the electric furnace main body 200 during operation. At least one of (F3 in FIG. 3) and powder carbon (C in FIG. 4) may be injected.

For example, the injection system 100 is formed to penetrate the wall of the upper cell 220 and is inclined downward at a predetermined angle toward the lower side of the electric furnace main body 200, so as to inject the electric furnace main body 200 during operation. CO gas is generated by blowing fuel (F4) or supersonic oxygen (F3) into the inner space, or by blowing powdered carbon (C) and supersonic oxygen (F3) into the molten steel (1) and slag (2) in the inner space. By doing so, the slag (2) can be formed.

Here, the injection system 100 is formed by penetrating the wall of the upper cell 220 of the electric furnace main body 200, but is not necessarily limited to FIG. 1 and is formed to penetrate the wall of the lower cell 210. may be formed. Additionally, a plurality of injection systems 100 may be installed as needed during the process.

To describe the injection system 100 in more detail, as shown in FIGS. 2 and 3, the injection system 100 injects fuel F4 and supersonic speed into the internal space of the electric furnace main body 200. A single nozzle assembly 10 capable of injecting at least one of a transport fluid F1 containing oxygen (F3) and powdery carbon (C), including a powdery carbon injection nozzle 110 and a film cooling The fluid nozzle 120, the supersonic oxygen nozzle 130, and the fuel nozzle 140 may be formed coaxially.

As shown in FIGS. 2 and 3, the powder carbon injection nozzle 110 is formed in the shape of a pipe with both ends open, and transfers the transfer fluid (F1) containing powder carbon (C) through the first injection passage therein. ) can be sprayed into the internal space of the electric furnace main body 200.

In addition, the film cooling fluid nozzle 120 is formed in the shape of a pipe with an end side closed at which the transport fluid F1 is sprayed so as to surround the powder carbon injection nozzle 110, and has a circular cross-section on the inside. The film cooling fluid F2 flowing through the formed second injection passage may be injected toward the first injection passage of the powder carbon injection nozzle 110.

For example, the powder carbon injection nozzle 110 has an outer wall surface and an inner surface of the powder carbon injection nozzle 110 so as to connect the first injection passage inside and the second injection passage of the film cooling fluid nozzle 120. A plurality of protective hole portions 111 may be formed to penetrate between wall surfaces.

More specifically, the plurality of protection hole portions 111 are formed at equal intervals along the circumferential direction and the longitudinal direction of the inner wall surface of the powder carbon injection nozzle 111, and are formed at equal intervals from the inner wall surface. The film cooling fluid (F2) may be injected toward the central axis of the first injection passage.

Accordingly, as shown in FIGS. 4 and 5, the film cooling fluid F2 flowing through the second injection passage of the film cooling fluid nozzle 120 flows into the powder carbon through the plurality of protection hole portions 111. It is injected as a high-speed jet onto the inner wall of the injection nozzle 110, forming a cooling protective film along the inner wall of the powdery carbon injection nozzle 110, thereby forming the first injection passage of the powdery carbon injection nozzle 110. It is possible to prevent the powdery carbon (C) passing by the transport fluid (F1) from colliding with the inner wall surface of the powdery carbon injection nozzle (110). At this time, the cooling protective film may also serve to cool the powder injection system 100 including the powder carbon injection nozzle 110 to prevent it from overheating.

In addition, the plurality of protection hole portions 111 provide transport fluid F1 flowing through the first injection passage of the powder carbon injection nozzle 110 as it moves from the outer wall surface of the powder carbon injection nozzle 110 to the inner wall surface. It may be formed inclined toward the direction of flow.

Accordingly, as shown in FIG. 5, the film cooling fluid is injected from the inner wall surface of the powder carbon injection nozzle 110 into a plurality of protection hole portions 111 formed inclined toward the flow direction of the transfer fluid F1. In the process of (F2) pushing the powder carbon (C) in an inclined direction toward the center of the powder carbon injection nozzle 110, the speed of the carbon powder (C) is further accelerated by the momentum of the film cooling fluid (F2). You can do it.

In addition, as shown in FIGS. 2 and 3, the supersonic oxygen nozzle 130 is formed in the shape of a pipe with both ends open to surround the membrane cooling fluid nozzle 120, and is formed to have a circular cross-section on the inside. Supersonic oxygen (F3) can be injected into the internal space of the electric furnace main body 200 at a Mach number of 1.0 or more through the third injection passage.

This supersonic fluid nozzle 130 is formed as a Laval nozzle to increase the flow speed of supersonic oxygen (F3) passing through the third injection passage to more than the speed of sound, thereby generating supersonic oxygen (F3) by the shroud effect. ) can further accelerate the flow speed beyond the speed of sound.

For example, the supersonic oxygen nozzle 130 is formed so that its cross-sectional area gradually decreases along the flow direction of the supersonic oxygen (F3) from the inlet into which the supersonic oxygen (F3) flows, so that it can be formed as the Laval nozzle, A compression section 131 that compresses the supersonic oxygen (F3) flowing inside, and a minimum cross-sectional area formed to maximize the compression of the supersonic oxygen (F3) compressed in the process of flowing through the compression section 131. The cross-sectional area is formed to gradually increase along the flow direction of the supersonic oxygen (F3) from the neck portion 132 to the injection portion where the supersonic oxygen (F3) is sprayed, and the supersonic oxygen (F3) flowing inside ) may be configured to include an expansion portion 133 that expands.

At this time, the compression section 131 and the expansion section 133 of the supersonic oxygen nozzle 130 change the cross-sectional area of the annular cross-section to gradually become smaller or larger in a non-linear manner, so that the third injection can be formed into an overall streamlined shape. It may be desirable to form a combination of at least two or more curves, including a convex curve formed in a convex curve shape based on the central axis of the flow path and a concave curve formed in a concave curve shape based on the central axis of the third injection flow path. there is.

For example, when each point of the compression part 131, the neck part 132, and the expansion part 133 of the supersonic oxygen nozzle 130 are linearly connected to form a straight line, the inner wall angle at which the inclination changes rapidly inside the nozzle This is formed, and a shock wave is generated during the compression/expansion flow of supersonic oxygen (F3). As a result, the shock wave causes the flow of supersonic oxygen (F3) to become unstable, adversely affecting the flow, and ultimately supersonic oxygen nozzle ( 130), the supersonic oxygen (F3) is not sufficiently accelerated, and straightness and momentum may deteriorate.

However, as in the present invention, when the supersonic oxygen nozzle 130 is formed in a streamlined shape with a combination of convex curves and concave curves, the generation of the shock wave due to the inner wall angle is suppressed, and the supersonic speed is controlled according to the principle of supersonic gas flow. By inducing the oxygen (F3) to accelerate stably, the straightness and momentum of the supersonic oxygen (F3) sprayed at a supersonic speed of Mach 1.0 or higher through the supersonic oxygen nozzle 130 can be improved.

In addition, as shown in FIGS. 2 and 3, the fuel nozzle 140 is formed in the shape of a pipe with both ends open to surround the supersonic oxygen nozzle 130, and is formed to have a circular cross-section on the inside. 4 Fuel F4 can be injected into the internal space of the electric furnace main body 200 through the injection passage.

The fuel nozzle 140 is formed in a ring shape with a spiral groove 141a so as to generate a swirl flow in the fuel F4 passing through the fourth injection passage, and has an annular cross section. The branch may include a swirler 141 inserted into the fourth injection passage.

Therefore, by applying the swirler 141 to the fuel nozzle 140 to generate a swirl flow in the fuel F4, the efficiency when mixing the fuel F4 and oxygen is improved, and the injection unit (to be described later through the swirl effect) 11) Combustion efficiency can be effectively improved.

As shown in FIGS. 2 and 3, the body carbon injection nozzle 110, the film cooling fluid nozzle 120, the supersonic oxygen nozzle 130, and the fuel nozzle 140 described above are coaxially formed. It can be formed as a single nozzle assembly (10).

At this time, the single nozzle assembly 10, through the powder carbon injection nozzle 110, the supersonic oxygen nozzle 130, and the fuel nozzle 140, fuel (F4), supersonic oxygen (F3), and powder carbon (C). At least one of the transport fluids (F1) containing fuel (F4), supersonic oxygen (F3), and powdery carbon (C) is applied to the portion of the injection port (11) that injects at least one or more of the transport fluids (F1) contained therein. The end of the injection port 11 of the powder carbon injection nozzle 110 and the supersonic oxygen nozzle 130 is connected to the injection port 11 of the fuel nozzle 140 so that a mixing space A in which one or more can be mixed is formed. It may be formed inside the single nozzle assembly 10 rather than the side end.

That is, compared to the fuel nozzle 140, which is formed coaxially with other nozzles and forms the outermost part of the single nozzle assembly 10, the powder carbon injection nozzle 110 and the supersonic oxygen nozzle 130 are formed shorter, thereby forming a single nozzle assembly. A predetermined mixing space (A) may be formed inside the injection hole 11 of (10).

At this time, the fuel nozzle 140 of the single nozzle assembly 10 has an injection port ( 11) At least a portion of the side end, the annular cross-section of the fourth injection passage may be formed to have a gradually smaller diameter toward the injection hole 11.

In this way, the fuel nozzle 140 is formed in a shape that is gathered toward the central axis as it moves toward the injection hole 11, so that the fuel F4 injected through the fuel nozzle 140 is gathered toward the mixing space A. By being injected, mixing efficiency is improved when mixing fuel F4 and oxygen, thereby effectively improving combustion efficiency in the injection unit 11.

In addition, in order to prevent the single nozzle assembly 10 from being excessively overheated by the heat of the internal space of the electric furnace main body 200, the fuel nozzle 140 formed on the outermost wall of the single nozzle assembly 10 is The annular outer wall is formed with a cooling passage 142 through which the cooling medium F5 flows, so that the single nozzle assembly 10 can be effectively cooled.

Therefore, according to the electric furnace injection system 100 and the electric furnace 1000 including the same according to an embodiment of the present invention, the powder carbon injection nozzle 110 is coaxial in the single nozzle assembly 10, and the film cooling The fluid nozzle 120, the supersonic oxygen nozzle 130, and the fuel nozzle 140 are formed to form a structure such that the oxygen lance, combustion burner, and powder injection are injected from the same central axis, as shown in FIGS. 6 to 9. At least one of a transport fluid (F1) containing fuel (F4), supersonic oxygen (F3), and powder carbon (C), such as oxygen lance mode 1, oxygen lance mode 2, combustion mode, and powder injection mode. Can be selectively sprayed depending on the mode.

In this way, by forming a structure so that the oxygen lance, combustion burner, and powder injection are injected from the same central axis in the single nozzle assembly 10, it can have the effect of increasing mixing ability, combustion efficiency, and injection efficiency, and the film cooling fluid It is possible to prevent destruction of the inner wall of the powder carbon injection nozzle 110 due to this, thereby increasing the replacement cycle and lifespan of the nozzle.

In addition, when using the powder injection mode, in the prior art, it was difficult to achieve a shroud effect because the central axes of the oxygen nozzle and the powder injection were different. However, a structure was designed so that the oxygen lance and the powder injection were injected from the same central axis in the single nozzle assembly 10. By forming this, effective powder injection through the shroud effect can be possible by supplying supersonic oxygen through an oxygen lance even when using the powder injection mode.

Therefore, reflecting the electric furnace process, oxygen lance, combustion burner, and powder injection modes can be selectively utilized in each stage from a single nozzle in the early, middle, late, and refining stages of scrap melting, and in addition to fluid supply for powder transfer, film cooling multi-hole Additional fluid is supplied from the nozzle to increase the speed of the powder at the injection nozzle, which has the advantage of inducing slag forming, and the shape of the supersonic nozzle for a shroud effect in the annular gap around the powder transfer pipe is applied to the supersonic characteristic curve to achieve stable supersonic fluid injection. By supplying a high Mach number fluid, the powder carbon passing through the powder transfer pipe is guided close to the upper surface of the slag without being disturbed by the surrounding environment, which has the effect of making the forming of the slag (2) more smooth. You can.

The present invention has been described with reference to the embodiments shown in the drawings, but these are merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true scope of technical protection of the present invention should be determined by the technical spirit of the attached patent claims.

1: molten steel
2: Slag
10: Single nozzle assembly
11: Nozzle
100: Powder injection system
110: powder carbon injection nozzle
111: Revenge of Protection Holder
120: Membrane cooling fluid nozzle
130: Supersonic fluid nozzle
131: Compression part
132: xylem
133: expansion part
140: Fuel nozzle
141: Swirler
141a: Spiral groove
142: Cooling flow path
200: Electric furnace main body
210: lower cell
220: upper cell
221: Slag discharge door
230: Loop part
300: Electrode
1000: Electric furnace
A: Mixed space
C: powder carbon
F1: Transport fluid
F2: Film cooling fluid
F3: Supersonic fluid
F4: Fuel
F5: Cooling medium

Claims (16)

It is inserted into one side of the electric furnace main body where an internal space capable of producing molten steel is formed by melting the iron source, and injects at least one of fuel, supersonic oxygen, and powdered carbon into the internal space of the electric furnace main body during operation. ) In the injection system for an electric furnace,
a powder carbon injection nozzle that is formed in the shape of a pipe with both ends open, and sprays the transfer fluid containing the powder carbon into the internal space of the electric furnace body through a first injection passage therein;
The film cooling fluid flowing through a second injection passage is formed in the shape of a pipe with a closed end at an end side through which the transfer fluid is sprayed to surround the powder carbon injection nozzle, and is formed to have a circular cross-section on the inside. a film cooling fluid nozzle that sprays toward the first injection passage;
Supersonic injection of the supersonic oxygen into the internal space of the electric furnace body through a third injection passage formed in the shape of a pipe open at both ends to surround the membrane cooling fluid nozzle and having an annular cross section on the inside. oxygen nozzle; and
a fuel nozzle that is formed in the shape of a pipe with both ends open to surround the supersonic oxygen nozzle and injects the fuel into the internal space of the electric furnace body through a fourth injection passage formed to have an annular cross section on the inside;
Including an injection system into an electric furnace. According to claim 1,
The fuel nozzle is,
a swirler formed in a ring shape with a spiral groove and inserted into the fourth injection passage having a circular cross-section to generate a swirl flow in the fuel passing through the fourth injection passage;
Including, an electric furnace injection system. According to claim 1,
The powder carbon injection nozzle, the film cooling fluid nozzle, the supersonic oxygen nozzle, and the fuel nozzle,
An electric furnace injection system formed coaxially to form one single nozzle assembly. According to claim 3,
The single nozzle assembly,
Through the powder carbon injection nozzle, the supersonic oxygen nozzle, and the fuel nozzle, the fuel, the supersonic oxygen, and the powder carbon are injected into an injection port portion that injects at least one or more of the fuel, the supersonic oxygen, and the powder carbon. To form a mixing space in which at least one or more of the above can be mixed, the injection port-side end of the powder carbon injection nozzle and the supersonic oxygen nozzle is located inside the single nozzle assembly rather than the injection port-side end of the fuel nozzle. Formed, electric furnace injection system. According to claim 4,
The fuel nozzle is,
At least a portion of the end on the injection port side has an annular cross-section extending toward the injection port so that the fuel injected through the fourth injection path can be injected in a form gathered toward the center of the mixing space. An electric furnace injection system that is formed with increasingly smaller diameters. According to claim 3,
The annular outer wall of the fuel nozzle formed by the outermost wall of the single nozzle assembly,
An electric furnace injection system in which a cooling passage through which a cooling medium flows is formed to cool the single nozzle assembly. According to claim 1,
The powder carbon injection nozzle is,
A plurality of protection holes are formed to penetrate between the outer wall surface and the inner wall surface of the powder carbon injection nozzle so as to connect the first injection flow path inside and the second injection flow path of the film cooling fluid nozzle, Injection system for electric furnace. According to claim 7,
The plurality of protective holes,
The inner wall surface of the powder carbon injection nozzle to prevent the powder carbon passing through the first injection passage of the powder carbon injection nozzle by the transfer fluid from colliding with the inner wall surface of the powder carbon injection nozzle. A plurality of units are formed at equal intervals along the circumferential direction and the longitudinal direction of the inner wall surface, and inject the film cooling fluid from the inner wall surface toward the central axis of the first injection passage. According to claim 8,
The plurality of protective holes,
An injection system for an electric furnace, which is formed to be inclined toward the flow direction of the transfer fluid flowing through the first injection passage of the powder carbon injection nozzle as it goes from the outer wall surface of the powder carbon injection nozzle to the inner wall surface. According to claim 1,
The supersonic oxygen nozzle,
An injection system for an electric furnace formed with a Laval nozzle to increase the flow rate of the supersonic oxygen passing through the third injection passage to more than the speed of sound. According to claim 10,
The supersonic oxygen nozzle,
A compression portion formed from an inlet into which the supersonic oxygen flows to have a gradually smaller cross-sectional area along the flow direction of the supersonic oxygen, and compresses the supersonic oxygen flowing therein;
a neck portion formed with a minimum cross-sectional area to maximize compression of the supersonic oxygen compressed in the process of flowing the compression portion; and
an expansion part formed so that its cross-sectional area gradually increases along the flow direction of the supersonic oxygen from the neck to the injection part where the supersonic oxygen is sprayed, and expands the supersonic oxygen flowing therein;
Including an injection system into an electric furnace. According to claim 11,
The compression portion and the expansion portion,
A convex curve formed in a convex curve shape with respect to the central axis of the third injection passage so that the cross-sectional area of the annular cross-section can be non-linearly changed to gradually become smaller or larger to form an overall streamlined shape, and the center of the third injection passage. An injection system for an electric furnace formed by a combination of at least two curves including a concave curve formed in a concave curve shape with respect to an axis. An electric furnace main body in which an internal space is formed into which the iron source can be charged and dissolved;
an electrode that is at least partially inserted into the interior space through the small ceiling of the loop portion on the upper side of the electric furnace main body to melt the iron source by arc heat so as to produce molten steel; and
An injection system that is inserted into one side of the electric furnace body and injects at least one of fuel, supersonic oxygen, and powdered carbon into the internal space of the electric furnace body during operation,
The injection system is,
a powder carbon injection nozzle that is formed in the shape of a pipe with both ends open, and sprays the transfer fluid containing the powder carbon into the internal space of the electric furnace body through a first injection passage therein;
The film cooling fluid flowing through a second injection passage is formed in the shape of a pipe with a closed end at an end side through which the transfer fluid is sprayed to surround the powder carbon injection nozzle, and is formed to have a circular cross-section on the inside. a film cooling fluid nozzle that sprays toward the first injection passage;
Supersonic injection of the supersonic oxygen into the internal space of the electric furnace body through a third injection passage formed in the shape of a pipe open at both ends to surround the membrane cooling fluid nozzle and having an annular cross section on the inside. oxygen nozzle; and
a fuel nozzle that is formed in the shape of a pipe with both ends open to surround the supersonic oxygen nozzle and injects the fuel into the internal space of the electric furnace body through a fourth injection passage formed to have an annular cross section on the inside;
Including, electric furnace. According to claim 13,
The electric furnace main body,
a lower cell forming the lower side of the interior space; and
an upper cell that is combined with the lower cell to form an upper side of the interior space and whose upper side is closed by the loop portion;
Including, electric furnace. According to claim 14,
The injection system is,
The powdered carbon injection nozzle, the film cooling fluid nozzle, the supersonic oxygen nozzle, and the fuel nozzle are formed as a single coaxial nozzle assembly, and are formed to penetrate the wall of the upper cell or the lower cell, With electricity. According to claim 15,
The injection system is,
An electric furnace formed to be inclined downward at a predetermined angle toward the lower side of the electric furnace main body.

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