Barrel-shaped flat-bottom electric arc furnace

Abstract

The invention provides a barrel-shaped flat-bottom electric arc furnace which comprises an upper furnace shell and a lower furnace shell, the upper furnace shell and the lower furnace shell are arranged in a matched mode, a molten pool is arranged on the inner side of the lower furnace shell, the bottom of a refractory layer arranged in the molten pool is parallel to the lower furnace shell, the bottom area of the refractory layer comprises a hot area and an eccentric area, and the hot area is of a plane structure and is arranged at one end of the bottom; the eccentric area is arranged at the other end of the bottom and is of an arc-shaped tilting slope surface structure, and a steel outlet is formed in the end of the tilting section. The device has the beneficial effects that the shape of the device is different from that of a traditional furnace bottom shell, a barrel-shaped flat-bottom electric arc furnace structure is adopted, and the sectional area of the horizontal plane of the barrel-shaped flat-bottom electric arc furnace bottom is increased; when the steel loading amount is the same, the liquid level height is lower than that of a common electric arc furnace, namely a molten pool is shallower, and the shape of molten steel in the electric arc furnace is flatter. Jet flow of the oxygen lance can penetrate into the molten steel; and the stirring effect of oxygen jet flow is achieved, rotation of the molten steel is accelerated, mixing of the molten steel in the cold area and the hot area is accelerated, the smelting time is shortened, and power consumption is reduced.

Description

Technical Field

[0001] The invention relates to the field of electric arc steelmaking, and more particularly to a barrel-shaped flat-bottom electric arc furnace. Background Art

[0002] In the prior art, when making steel, scrap steel is placed in the lower shell of an electric arc furnace, and electrodes are inserted on the upper part. The electric arc of the electrodes releases heat to melt the scrap steel into molten steel. In order to smoothly carry out steelmaking, refractory materials are required to isolate the heat generated by the electrodes. In the lower shell of the electric arc furnace, a molten pool of a certain shape is made of refractory materials, and the scrap steel is melted in the molten pool.

[0003] The shell structure of the electric arc furnace adopts the structure of upper shell and lower shell. In order to improve steelmaking efficiency and reduce energy consumption, oxygen guns and carbon powder guns are usually installed on the lower shell or upper shell to spray oxygen and carbon powder into the furnace.

[0004] The lower furnace shell is generally composed of the furnace body shell and the furnace bottom shell, which are welded by steel plates. Refractory materials are laid in the lower furnace shell to form a certain shape to hold molten steel. The furnace bottom shell steel plate adopts a bowl-shaped structure with a low middle and raised ends. During steelmaking, refractory materials are laid on the bottom of the furnace to isolate the heat generated during steelmaking and ensure smooth steelmaking. The laying method is to lay ramming materials at the bottom of the lower furnace shell of the electric arc furnace and use magnesium bricks to build it around.

[0005] At present, the refractory material setting methods inside the molten pool and the problems caused by them mainly include the following two types:

[0006] 1. The electric arc furnace is made of heat-resistant material into a bowl-shaped furnace, and the ramming material at the bottom of the furnace is parallel to the bottom of the furnace.

[0007] The problems with this structure are that the steel loading capacity is small and the molten pool is too deep to fully utilize the oxygen lance.

[0008] 2. The electric arc furnace is made of heat-resistant materials and has a flat-bottomed furnace shape, with a furnace slope made on the edge of the flat-bottomed furnace.

[0009] The problem with this structure is that although the steel loading capacity is increased compared to the former, its molten pool is deeper, and the oxygen lance cannot fully play its role. In addition, the thickness of the heat-resistant material layer and the furnace bottom steel plate are different, which will cause uneven heating. On this basis, the existence of the furnace slope will cause the slag floating on the surface of the molten steel to directly contact the furnace slope made of ramming material, causing corrosion, affecting the overall life of the steelmaking furnace. Summary of the invention

[0010] The invention overcomes the shortcomings of the prior art and provides a barrel-shaped flat-bottom electric arc furnace.

[0011] The purpose of the present invention is achieved through the following technical solutions.

[0012] The barrel-shaped flat-bottom electric arc furnace comprises an upper furnace shell and a lower furnace shell, which are arranged in coordination with each other. A molten pool is arranged on the inner side of the lower furnace shell. The bottom of the refractory layer arranged in the molten pool is arranged parallel to the lower furnace shell. The bottom area of ​​the refractory layer comprises a hot zone and an eccentric zone. The hot zone is a plane structure arranged at one end of the bottom, and the eccentric zone is arranged at the other end of the bottom in an arc-shaped sloped surface structure, and a steel outlet is arranged at the end position of the raised section.

[0013] The lower furnace shell comprises a furnace body shell and a furnace bottom shell, the furnace body shell and the furnace bottom shell are fixedly connected, and a molten pool is formed inside the furnace body shell and the furnace bottom shell.

[0014] The refractory layer arranged on the furnace bottom shell comprises a fired magnesia brick layer and a furnace bottom ramming material layer, and the furnace bottom ramming material layer is arranged on the fired magnesia brick layer.

[0015] The fired magnesia brick layer and the furnace bottom ramming material layer are arranged parallel to the furnace bottom shell.

[0016] The refractory layer arranged on the inner side of the furnace shell is made of magnesia carbon bricks.

[0017] The thickness of the furnace bottom ramming material layer is greater than or equal to 800 mm.

[0018] The cross section of the molten pool is a water droplet-like structure, and the hot zone is set at the larger end of the water droplet.

[0019] The upper furnace shell and the lower furnace shell are equipped with an oxygen gun and a carbon powder gun.

[0020] The beneficial effects of the present invention are:

[0021] This device is different from the traditional furnace bottom shell shape. It adopts a barrel-shaped flat-bottom electric arc furnace structure. Compared with the traditional electric arc furnace bottom shape, the horizontal cross-sectional area of ​​the barrel-shaped flat-bottom electric arc furnace bottom is increased; when the amount of steel is the same, the liquid level is lower than that of the ordinary electric arc furnace, that is, the molten pool is shallower, and the shape of the molten steel in the electric arc furnace is flatter. It is not only conducive to the oxygen lance jet to penetrate into the molten steel; it is also conducive to the stirring effect of the oxygen jet, accelerating the rotation of the molten steel, accelerating the mixing of the cold zone and hot zone molten steel, shortening the smelting time, and reducing power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of the present invention;

[0023] Figure 2 is a longitudinal cross-sectional view of the present invention;

[0024] Figure 3 is a transverse cross-sectional view of the present invention;

[0025] Figure 4 is a top view of the lower furnace shell of the present invention;

[0026] Figure 5 It is a schematic diagram of the settings of the oxygen gun and the carbon powder gun;

[0027] In the figure: 1. upper furnace shell; 2. lower furnace shell; 21. furnace body shell; 22. furnace bottom shell; 3. molten pool; 4. hot zone; 5. eccentric zone; 6. steel outlet; 7. refractory layer; 71. fired magnesia brick layer; 72. furnace bottom ramming material layer; 8. oxygen gun; 9. carbon powder gun. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further described below through specific embodiments.

[0029] Example

[0030] A barrel-shaped flat-bottom electric arc furnace comprises an upper furnace shell 1 and a lower furnace shell 2, which are arranged in coordination with each other. A molten pool 3 is arranged on the inner side of the lower furnace shell 2. A refractory layer 7 arranged in the molten pool 3 is arranged parallel to the bottom of the lower furnace shell 2. The bottom area of ​​the refractory layer 7 comprises a hot zone 4 and an eccentric zone 5. The hot zone 4 is a planar structure arranged at one end of the bottom, and the eccentric zone 5 is arranged at the other end of the bottom in an arc-shaped sloped surface structure, and a steel outlet 7 is arranged at the end position of the raised section.

[0031] The lower furnace shell 2 includes a furnace body shell 21 and a furnace bottom shell 22 . The furnace body shell 21 and the furnace bottom shell 22 are fixedly connected, and a molten pool 3 is formed inside the furnace body shell 21 and the furnace bottom shell 22 .

[0032] The refractory layer 7 disposed on the furnace bottom shell 22 includes a fired magnesia brick layer 71 and a furnace bottom ramming material layer 72 . The furnace bottom ramming material layer 72 is disposed on the fired magnesia brick layer 71 .

[0033] The fired magnesia brick layer 71 and the furnace bottom ramming material layer 72 are arranged parallel to the furnace bottom shell 22 .

[0034] The refractory layer 7 disposed inside the furnace shell 21 is made of magnesia carbon bricks.

[0035] The thickness of the furnace bottom ramming material layer 72 is greater than or equal to 800 mm.

[0036] The cross section of the molten pool 3 is a water drop-like structure, and the hot zone 4 is arranged at the larger end of the water drop shape.

[0037] The upper furnace shell 1 and the lower furnace shell 2 are equipped with an oxygen gun 8 and a carbon powder gun 9 .

[0038] The working principle of the present invention is as follows: Figure 1-4 As shown, the steelmaking furnace adopts an upper furnace shell 1 and a lower furnace shell 2 to form a complete furnace body. The molten steel is melted by the molten pool 3 and then tapped from the tapping port 7.

[0039] This device improves the laying method of refractory materials so that the refractory materials and the furnace bottom shell 22 structure of the barrel-shaped flat-bottom electric arc furnace remain parallel during steelmaking. Since the shape of the furnace bottom shell 22 of the barrel-shaped flat-bottom electric arc furnace is a plane at one end and tilted at the other end. The refractory materials at the bottom of the barrel-shaped flat-bottom electric arc furnace are arranged parallel to it. The distance between the refractory materials and the furnace bottom shell 22 is equal, so there is no weak point and no problem of local overheating. Because the furnace bottom ramming material layer 72 of the bottom refractory material is not provided with a furnace slope, the waste slag on the surface of the molten steel will not contact the furnace bottom ramming material layer 72, but will contact the corrosion-resistant magnesia carbon bricks, which can effectively extend the life of the furnace body.

[0040] Preferably, laying a furnace bottom ramming material layer 72 of 800 mm on the bottom can ensure safety without increasing the furnace slope, thereby saving ramming material and having good safety performance.

[0041] like Figure 5 As shown, due to the adoption of a flat bottom structure, the depth of the molten pool for the same amount of steel is also reduced, so the heights of the oxygen lance 8 and the carbon powder gun 9 installed on the barrel-shaped flat bottom electric arc furnace are also reduced.

[0042] The carbon powder gun 9 and the oxygen-combustion gun 8 are arranged up and down, with the oxygen-combustion gun 8 being arranged up and down, and the carbon powder gun 9 being arranged down.

[0043] Taking a 70-ton electric arc furnace as an example, the installation height of the oxygen gun 8 and the carbon powder gun 9 can be reduced by more than 250 mm compared with the installation height of a traditional electric arc furnace.

[0044] The oxygen jet ejected by the oxygen lance 8 attenuates as the distance increases. The oxygen lance 8 ejects the oxygen jet, and the closer the oxygen lance is to the molten steel surface, the better the effect. After the installation height of the oxygen lance 8 is determined, the impact on the molten steel: in the early stage of smelting, the molten steel level is low, the oxygen lance 8 is far away from the molten steel level, the oxygen jet penetrates the molten steel level and acts on the molten steel, and the stirring effect of the oxygen lance 8 jet on the molten steel is weak. As the scrap steel is melted, the molten steel level gradually rises, the distance between the oxygen lance 8 and the molten steel level is shortened, the oxygen jet penetrates the molten steel level and acts on the molten steel, and the stirring effect of the oxygen lance jet on the molten steel is enhanced. Therefore, lowering the setting height of the oxygen lance 8 is conducive to the oxygen jet of the oxygen lance penetrating into the molten steel, which can give full play to the role of the oxygen lance; it is conducive to exerting the stirring effect of the oxygen jet, accelerating the rotation of the molten steel, accelerating the mixing of the molten steel in the cold zone and the hot zone, shortening the smelting time, and reducing power consumption.

[0045] The embodiments of the present invention are described in detail above, but the contents described are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. Barrel-shaped flat-bottom electric arc furnace, characterized by: It includes an upper furnace shell and a lower furnace shell, which are arranged in coordination with each other. A molten pool is arranged on the inner side of the lower furnace shell. The bottom of the refractory layer arranged in the molten pool is arranged parallel to the lower furnace shell. The bottom area of ​​the refractory layer includes a hot zone and an eccentric zone. The hot zone is a plane structure arranged at one end of the bottom, and the eccentric zone is arranged at the other end of the bottom in an arc-shaped sloped surface structure. A steel outlet is arranged at the end position of the raised section.

2. The barrel-shaped flat-bottomed electric arc furnace according to claim 1, characterized in that: The lower furnace shell comprises a furnace body shell and a furnace bottom shell, the furnace body shell and the furnace bottom shell are fixedly connected, and a molten pool is formed inside the furnace body shell and the furnace bottom shell.

3. The barrel-shaped flat-bottomed electric arc furnace according to claim 2, characterized in that: The refractory layer arranged on the furnace bottom shell comprises a fired magnesia brick layer and a furnace bottom ramming material layer, and the furnace bottom ramming material layer is arranged on the fired magnesia brick layer.

4. The barrel-shaped flat-bottomed electric arc furnace according to claim 3, characterized in that: The fired magnesia brick layer and the furnace bottom ramming material layer are arranged in parallel with the furnace bottom shell.

5. The barrel-shaped flat-bottomed electric arc furnace according to claim 2, characterized in that: The refractory layer arranged on the inner side of the furnace shell is made of magnesia carbon bricks.

6. The barrel-shaped flat-bottomed electric arc furnace according to claim 3, characterized in that: The thickness of the furnace bottom ramming material layer is greater than or equal to 800mm.

7. The barrel-shaped flat-bottomed electric arc furnace according to claim 1, characterized in that: The cross section of the molten pool is a water droplet-like structure, and the hot zone is arranged at the larger end of the water droplet shape.

8. The barrel-shaped flat-bottomed electric arc furnace according to claim 1, characterized in that: The upper furnace shell and the lower furnace shell are cooperatively provided with an oxygen-burning gun and a carbon powder gun.

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