KR20240069152A - Manufacturing equipment for direct reduction iron with trnasfer duct - Google Patents

Abstract

The direct reduced iron production device includes a multi-stage fluidized reduction furnace and a plurality of transfer pipes. The multi-stage fluidized reduction furnace reduces and sinters powdered iron ore and auxiliary materials by contacting them with high-temperature reducing gas. A plurality of transfer pipes are connected to and installed in a multi-stage fluidized reduction furnace to transport powdered iron ore and gas, and include a guide tube penetrating the fluidized reduction furnace and an inner tube fixed to the inside of the guide tube. The inner tube includes an upper part and a lower part integrally joined by a welding part, and the welding part includes at least one hook part formed by combining the protrusions and recesses of the upper part and the lower part.

Description

Directly reduced iron manufacturing equipment equipped with a transfer pipe {MANUFACTURING EQUIPMENT FOR DIRECT REDUCTION IRON WITH TRNASFER DUCT}

The present invention relates to a direct reduced iron production device, and more specifically, to a direct reduced iron production device with an improved structure of a transfer pipe for transferring direct reduced iron.

The molten iron manufacturing facility, known as FINEX, includes a direct reduction iron (DRI) manufacturing unit, an agglomeration unit, and a molten gasifier. The direct reduced iron production device consists of a multi-stage fluidized reduction furnace that reduces and calcifies powdered iron ore and auxiliary materials by contacting them with high-temperature reducing gas.

The agglomeration device agglomerates directly reduced iron discharged from the final flow reduction furnace to produce reduced agglomerated material, and the melting gasification furnace produces molten iron and slag by heating, melting, and slagging the reduced agglomerated material and auxiliary materials. The gas discharged from the melt gasifier is supplied as reducing gas to a multi-stage fluidized reduction furnace.

The multi-stage flow reduction reactor is connected by a first transfer pipe called a stand pipe, and the final flow reduction reactor and the feed bin of the agglomeration device are connected by a second transfer pipe called a riser pipe. . The first transfer pipe transfers iron ore and reduced iron from the previous fluid reduction reactor to the next fluid reduction reactor, and the second transfer pipe transfers the reduced iron from the final fluid reduction reactor to the feed bin.

At this time, the transfer of reduced iron is carried out using a pneumatic transfer method using the pressure difference between the front and rear devices. The first and second transfer pipes include an inner tube located inside and outside the fluid reduction furnace at a portion coupled to the fluid reduction furnace.

Due to the nature of the transfer method, the inner tubes of the first and second transfer pipes play a role in protecting the refractory of the fluidized reduction furnace within a closed space. However, defects may occur due to direct reduced iron or partial burnout of the equipment due to eddy currents occurring near the inner tube. There is a problem of flow failure caused by substances, etc.

In addition, the first and second transfer pipes are made of austenitic steel and have multiple welded sections. If the welded section becomes weak due to long-term use and cracks or damage occur, the inner tube is inside the fluidized reduction furnace. may fall to In this case, the flow of directly reduced iron and gas is reduced or poor, making the operating situation unstable.

The present invention improves the welding structure of the inner tube to prevent the inner tube from falling out inside the fluidized reduction furnace even when cracks occur due to long-term use, and to stably maintain the flow of directly reduced iron and gas inside the fluidized reduction furnace. The aim is to provide a direct reduced iron production device that can improve the operation rate of the fluidized reduction furnace process.

An apparatus for producing direct reduced iron according to an embodiment of the present invention includes a multi-stage fluidized reduction furnace and a plurality of transfer pipes. The multi-stage fluidized reduction furnace reduces and sinters powdered iron ore and auxiliary materials by contacting them with high-temperature reducing gas. A plurality of transfer pipes are connected to and installed in a multi-stage fluidized reduction furnace to transport powdered iron ore and gas, and include a guide tube penetrating the fluidized reduction furnace and an inner tube fixed to the inside of the guide tube. The inner tube includes an upper part and a lower part integrally joined by a welding part, and the welding part includes at least one hook part formed by combining the protrusions and recesses of the upper part and the lower part.

A first protrusion and a first concave portion may be located at an end of the upper portion facing the lower portion, and a second protrusion and a second concave portion may be located at an end of the lower portion toward the upper portion. The first protrusion may be fitted into the second recess, and the second protrusion may be fitted into the first recess.

The ends of the upper part and the lower part may be parallel to the circumferential direction, and the first protrusion and the first concave part may be located at two positions facing each other along the radial direction at the end of the upper part.

The first protrusion may have a shape whose width in the circumferential direction gradually increases as it moves away from the upper part, and the second protrusion may have a shape whose width in the circumferential direction gradually increases as it moves away from the lower part.

The welding portion may be provided along the boundary between the upper and lower sides by butt welding with the first protrusion fitting into the second recess and the second protrusion fitting into the first recess.

The welding portion may include an arc portion parallel to the circumferential direction of the inner tube, a first hook portion corresponding to the boundary of the first protrusion and the second recess, and a second hook portion corresponding to the boundary of the second protrusion and the second recess. there is.

The guide tube may surround the entire upper portion and a portion of the lower portion. Each of the plurality of transfer pipes may further include a flange coupled to an end of the upper portion, a purge pipe and a round bar coupled to an end of the lower portion.

In the direct reduced iron manufacturing apparatus according to one embodiment, the inner tube of the transfer pipe includes an upper part and a lower part joined by a welding part having at least one hook part. At least one hook firmly holds the lower part to prevent the lower part from falling off during operation, thereby enabling stable operation.

1 is a configuration diagram of a direct reduced iron production apparatus according to an embodiment of the present invention.
FIG. 2 is a configuration diagram showing a portion of the first fluidized reduction reactor and the second transfer pipe in the direct reduced iron production apparatus shown in FIG. 1.
Figure 3 is a configuration diagram showing the inner tube of a comparative example.
Figure 4 is a photograph showing the inner tube of the comparative example separated from the fluidized reduction furnace.
FIG. 5 is a configuration diagram showing the inner tube and guide tube of the transfer pipe in the direct reduced iron production device shown in FIG. 1.
FIG. 6 is a cross-sectional view of the inner tube of the transfer pipe shown in FIG. 4.
FIG. 7 is a view showing the inner tube shown in FIG. 6 in a separated state.
Figure 8 is a configuration diagram showing the welded portion of the inner tube.
Figure 9 is a photograph showing the actual manufactured product of the upper portion of the inner tube shown in Figure 7.
Figure 10 is a photograph showing the actual manufactured product of the lower part of the inner tube shown in Figure 7.
Figure 11 is a photograph of the inner tube in which the upper part of Figure 9 and the lower part of Figure 10 are combined.
Figure 12 is a photograph showing the installation process of the inner tube shown in Figure 11.

Hereinafter, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. The present invention may be implemented in many different forms and is not limited to the embodiments described herein.

1 is a configuration diagram of a direct reduced iron production apparatus according to an embodiment of the present invention.

Referring to FIG. 1, the direct reduced iron manufacturing apparatus 100 includes a multi-stage fluidized reduction furnace (R1 to R4) that reduces and sinters powdered iron ore and auxiliary materials by contacting them with a high-temperature reducing gas, and a multi-stage fluidized reduction furnace (R1 to R4). It includes a plurality of transfer pipes (10, 20) connected to R4). The multi-stage fluidized reduction reactors (R1 to R4) may be composed of four fluidized reducing reactors, but the number of fluidized reducing reactors is not limited to the example shown.

The multi-stage fluidized reduction furnaces (R1 to R4) may be composed of, for example, first, second, third, and fourth fluidized reduction furnaces (R1, R2, R3, and R4). The powdered iron ore is charged into the fourth fluidized reduction furnace (R4) along a charging hopper (not shown), and then moves to the third, second, and first fluidized reduction furnaces (R3, R2, and R1) in that order. The high-temperature reducing gas sequentially moves through the first, second, third, and fourth fluidized reduction reactors (R1, R2, R3, and R4) in the opposite direction to the powdered iron ore.

Inside the multi-stage fluidized reduction furnaces (R1 to R4), powdered iron ore meets high-temperature reduction gas and becomes reduced iron, and the first fluidized reduction furnace (R1) becomes the final fluidized reduction furnace that directly discharges the reduced iron. The fourth fluidized reduction furnace (R4) is about 300°C to 400°C, the third fluidized reduction furnace (R3) is about 550°C to 650°C, and the second fluidized reduction furnace (R2) is about 650°C to 750°C. The fluidized reduction furnace (R1) reduces powdered iron ore in a reducing atmosphere of about 700°C to 800°C.

Directly reduced iron discharged from the first fluidized reduction reactor (R1) is transferred to a feed bin (not shown) of the agglomeration device, and the agglomeration device directly agglomerates the reduced iron to produce a reduced agglomerated material. A melting gasifier (not shown) produces molten iron and slag by heating, melting, and slagging reduced compacted materials and secondary raw materials. The gas discharged from the melt gasification furnace is supplied as a reducing gas to the multi-stage fluidized reduction furnaces (R1 to R4).

The molten iron manufacturing facility, called FINEX, uses powdered iron ore and steam coal, so the coke process and sintering process required for the operation of existing blast furnace facilities can be omitted, and the multi-stage fluidized reduction furnace (R1 to R4) performs desulfurization. In addition, because the melt gasifier uses pure oxygen, the emissions of sulfur oxides, nitrogen oxides, and carbon dioxide generated during preliminary treatment are significantly lower than those of existing blast furnace facilities.

A plurality of transfer pipes 10 and 20 are connected to and installed in multi-stage fluidized reduction reactors (R1 to R4), and transport powdered iron ore together with gas. That is, the powdered iron ore undergoes a temperature increase and reduction process while moving towards the low flow reduction furnace by gravity through a plurality of transfer pipes 10 and 20, and moves together with the gas due to the pressure difference in the flow reduction furnace. A plurality of transfer pipes 10 and 20 transfer powdered iron ore using a pneumatic transfer method.

A plurality of transfer pipes (10, 20) are located between the charging hopper (not shown) and the fourth flow reduction furnace (R4), and the first transfer pipe (10) located between the multi-stage flow reduction furnaces (R1 to R4) ) and a second transfer pipe 20 located between the first flow reduction reactor (R1) and the feed bin. The first conveying pipe 10 may be referred to as a stand pipe, and the second conveying pipe 20 may be referred to as a riser pipe.

The first transfer pipes 10 are two between the charging hopper and the fourth flow reduction furnace (R4), two between the fourth flow reduction furnace (R4) and the third flow reduction furnace (R3), and the third flow reduction furnace. Two may be installed between the furnace (R3) and the second fluidized reduction furnace (R2), and two may be installed between the second fluidized reduction furnace (R2) and the first fluidized reduction furnace (R1). Four second transfer pipes 20 may be installed between the first flow reduction reactor (R1) and the feed bin. The number of first and second transfer pipes 10 and 20 is not limited to the above examples.

FIG. 2 is a configuration diagram showing a portion of the first fluidized reduction reactor and the second transfer pipe in the direct reduced iron production apparatus shown in FIG. 1.

Referring to FIGS. 1 and 2, the second transfer pipe 20 is an inner tube that passes through the first fluid reduction furnace (R1) and is located inside and outside the first fluid reduction furnace (R1). It includes (30) and a guide tube (50).

The guide tube 50 is fixed to the first fluid reduction furnace (R1) in contact with the main body of the first fluid reduction furnace (R1), and surrounds a portion of the inner tube 30. The inner tube 30 is located inside the guide tube 50 and has a length greater than the guide tube 50. The exposed portion of the inner tube 30 that is not surrounded by the guide tube 50 is positioned expanded toward the inside of the first flow reduction furnace (R1).

Although the second transfer pipe 20 is shown in FIG. 2, the first transfer pipe 10 also includes an inner tube 30 and a guide tube 50 of the same configuration as the second transfer pipe 20. That is, the first transfer pipe 10 has different inclination angles and is provided with an inner tube 30 and a guide tube 50 that penetrate the multi-stage flow reduction furnaces (R1 to R4).

In FIG. 1 , the circular dotted area indicates a portion of the first transfer pipe 10 where the inner tube and the guide tube are located, and a portion of the second transfer pipe 20 where the inner tube and the guide tube are located.

Figure 3 is a configuration diagram showing the inner tube of a comparative example.

Referring to FIG. 3, the inner tube 60 of the comparative example according to the prior art is composed of an upper portion 62 and a lower portion 63 integrally joined by a welding portion 61. At this time, the welded portion 61 is a ring-shaped welded portion parallel to the circumferential direction of the inner tube 60, and is provided by straight butt welding. The guide tube 70 surrounds the entire upper portion 62 and a portion of the lower portion 63.

Thermal expansion of the inner tube 60 occurs due to the high temperature environment of the fluidized reduction furnace. In particular, surface hardening and brittleness of the welded portion 61 occur when exposed to high temperatures for a long time, and the lower part 63 exposed to the inside of the fluidized reduction furnace ) Cracks may occur due to surrounding eddies and vibrations. When the crack in the welded portion 61 expands, the lower portion 63 of the inner tube 60 may gradually separate from the upper portion 62 and fall into the interior of the fluidized reduction furnace.

Figure 4 is a photograph showing the inner tube of the comparative example separated from the fluidized reduction furnace, showing the state in which the upper and lower parts were separated due to damage to the weld zone. In Figure 4, the red circle indicates a damaged weld area.

FIG. 5 is a configuration diagram showing the inner tube and guide tube of the transfer pipe in the direct reduced iron manufacturing apparatus shown in FIG. 1, and FIG. 6 is a cross-sectional view of the inner tube of the transfer pipe shown in FIG. 4. FIG. 7 is a diagram showing the inner tube shown in FIG. 6 in a separated state, and FIG. 8 is a configuration diagram showing the welded portion of the inner tube.

Referring to Figures 5 to 8, each of the transfer pipes 10 and 20 according to one embodiment is an inner tube 30 consisting of an upper part 32 and a lower part 33 integrally joined by a welding part 31. ), the flange 41 coupled to the end of the upper part 32, the purge pipe 42 and the round bar 43 coupled to the end of the lower part 33, and the entire upper part 32 and It includes a guide tube 50 surrounding a portion of the lower part 33.

The inner tube 30 is in direct contact with the gas and reduced iron and transports the gas and reduced iron, and the flange 41 functions to fix the inner tube 30. The purge pipe 42 functions to eliminate signs of blockage by spraying high-pressure inert gas when there are signs of blockage at the entrance of the inner tube 30. The round bar 43 functions as a grid to prevent large foreign substances from entering the inner tube 30, and the guide tube 50 serves as a guide when installing the inner tube 30.

A first protrusion 34 and a first concave portion 35 are located at the end of the upper portion 32 facing the lower portion 33 in the inner tube 30, and the lower portion 33 faces the upper portion 32. A second protrusion 36 and a second concave portion 37 are located at the ends of . The first protrusion 34 is fitted into the second recess 37, and the second protrusion 36 is fitted into the first recess 35. Butt welding is performed while the first and second protrusions 34 and 36 are fitted into the second and first recesses 37 and 35, and a welded portion 31 is formed on their joining surfaces.

The end of the upper portion 32 is basically parallel to the circumferential direction, and the first protrusion 34 and the first concave portion 35 are located at two points facing each other along the radial direction. The first protrusion 34 is formed to protrude toward the lower side 33, and the first concave portion 35 is formed to be concave toward the upper side 32. The first protrusion 34 may have a shape whose width in the circumferential direction gradually increases as it moves away from the upper portion 32, and may be formed in an approximate inverted trapezoidal shape.

The end of the lower part 33 is also basically parallel to the circumferential direction, and the second protrusion 36 and the second concave part 37 are located at two points facing each other along the radial direction. The second protrusion 36 is formed to protrude toward the upper portion 32, and the second concave portion 37 is formed to be concave toward the lower portion 33. The second protrusion 36 may have a shape whose width in the circumferential direction gradually increases as it moves away from the lower part 33, and may be formed in an approximate inverted trapezoidal shape.

Since the second concave portion 37 is a part that accommodates the first protrusion 34, it has the same shape as the first protrusion 34, and the first concave portion 35 is a part that accommodates the second protrusion 36. It has the same shape as the second protrusion 36. The upper part 32 and the lower part 33 are aligned so that the first protrusion 34 fits into the second recess 37 and the second protrusion 36 fits into the first recess 35, butt. They are integrally joined by forming a welded portion 31 by welding.

The weld portion 31 includes an arc portion 311 parallel to the circumferential direction of the inner tube 30, a first hook portion 312 corresponding to the boundary between the first protrusion 34 and the second concave portion 37, It may include a second hook 313 corresponding to the boundary between the second protrusion 36 and the first recess 35. The first and second hooks 312 and 313 function to firmly hold the lower part 33 and prevent the lower part 33 from gradually separating from the upper part 32 and falling off.

The long and inclined lower part 33 continuously receives downward force caused by gravity and shock from vortices and vibrations, and includes a first hook 312 and a second hook portion (312) formed in a roughly inverted trapezoidal shape. 313) functions to lock the lower part 33. Therefore, the lower part 33 is not separated from the upper part 32 even when exposed to a high temperature environment for a long period of time, and the flow of gas and reduced iron can be stably maintained.

In addition, the inner tube 30 of the above-described configuration can minimize heavy work that requires dismantling the large valve, compensator, gas duct, etc. at the rear end, which is additionally generated during replacement work, and can improve safety. And since the flange (41) can be recycled, the cost of purchasing equipment can be reduced.

Figure 9 is a photograph showing the actual manufactured product of the upper part of the inner tube shown in Figure 7, and Figure 10 is a photograph showing the actual manufactured product of the lower part of the inner tube shown in Figure 7. FIG. 11 is a photograph of the inner tube in which the upper portion of FIG. 9 and the lower portion of FIG. 10 are combined, and FIG. 12 is a photograph showing the installation process of the inner tube shown in FIG. 11.

As described above, the direct reduced iron manufacturing apparatus 100 according to an embodiment includes a multi-stage flow reduction furnace (R1 to R4) and a plurality of transfer pipes 10 and 20, and a plurality of transfer pipes 10 and 20 ) Each includes an inner tube 30. The inner tube 30 includes an upper part 32 and a lower part 33 joined by a welding part 31 having at least one hook part 312, 313. At least one hook (312, 313) firmly holds the lower part (33) to prevent the lower part (33) from falling off during operation, thereby enabling stable operation.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited thereto, and can be implemented with various modifications within the scope of the claims, the detailed description of the invention, and the accompanying drawings, and this is also the present invention. It is natural that it falls within the scope of .

100: Direct reduction iron production device R1, R2, R3, R4: Fluidized reduction furnace
10: first transfer pipe 20: second transfer pipe
30: Inner tube 31: Welded portion
311: arcuate portion 312: first hook portion
313: second hook 32: upper part
33: lower part 34: first protrusion
35: first concave portion 36: second protrusion
37: second recess 41: flange
42: purge pipe 43: round bar
50: Guide tube

Claims (7)

A multi-stage fluidized reduction furnace that reduces and calcifies powdered iron ore and auxiliary materials by contacting them with high-temperature reducing gas; and
It is connected to the multi-stage fluidized reduction furnace to transport powdered iron ore and gas, and includes a plurality of transfer pipes including a guide tube penetrating the fluidized reduction furnace and an inner tube fixed to the inside of the guide tube,
The inner tube includes an upper portion and a lower portion integrally joined by a welding portion, and the welding portion includes at least one hook portion formed by combining the protrusions and recesses of the upper portion and the lower portion. According to paragraph 1,
A first protrusion and a first concave portion are located at an end of the upper portion facing the lower portion, a second protrusion and a second concave portion are located at an end of the lower portion toward the upper portion, and the first protrusion is fitted into the second concave portion. , a direct reduced iron manufacturing device in which the second protrusion is fitted into the first recess. According to paragraph 2,
The ends of the upper portion and the lower portion are basically parallel to the circumferential direction, and the first protrusion and the first concave portion are located at two positions facing each other along the radial direction at the end of the upper portion. Directly reduced iron manufacturing apparatus. According to paragraph 2,
The first protrusion has a shape whose width in the circumferential direction gradually increases as it moves away from the upper part, and the second protrusion has a shape whose width in the circumferential direction gradually increases as it moves away from the lower part. Directly reduced iron production device. According to paragraph 4,
The welding portion is provided along the boundary surface of the upper portion and the lower portion by butt welding with the first protrusion being inserted into the second concave portion and the second protrusion being being inserted into the first concave portion. Device. According to clause 5,
The welding portion includes an arc portion parallel to the circumferential direction of the inner tube, a first hook portion corresponding to the boundary of the first protrusion and the second recess, and a first hook portion corresponding to the boundary of the second protrusion and the second recess. 2 Directly reduced iron manufacturing device including a hanging part. According to any one of claims 1 to 6,
The guide tube surrounds the entire upper portion and a portion of the lower portion, and each of the plurality of transfer pipes further includes a flange coupled to an end of the upper portion, a purge pipe and a round bar coupled to an end of the lower portion. manufacturing device.

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