Cooling wall for blast furnaces

Abstract

The utility model provides a cooling wall for blast furnace, including the cooling wall matrix, the cooling water pipe of two ends of inside arrangement of cooling wall matrix projects cooling water pipe, the bending of cooling water pipe, because the pipe wall thinning amount caused by bending is 15% less than wall thickness. Cooling water pipe thick wall is 8mm. The utility model can effectively prolong the service life of cooling water pipe, and then can effectively prolong the service life of cooling wall 2-3 years.

Description

Technical Field

[0001] This utility model belongs to the field of cooling walls for blast furnace cooling in blast furnace ironmaking process, and specifically relates to a cooling wall for blast furnace. Background Technology

[0002] In blast furnace ironmaking, the blast furnace is the "heart" of the process, where all core smelting reactions and material-energy conversions take place. Its performance directly affects the efficiency and economy of the entire steel production. The core equipment of the blast furnace is the cooling wall, whose main function is to protect the furnace body and maintain stable operation. The blast furnace interior is extremely hot; the cooling wall absorbs heat through circulating cooling water, reducing the temperature of the furnace shell and refractory lining, preventing deformation, burning, or melting due to high temperatures, and extending the service life of the furnace structure. The cooling wall inhibits excessive erosion and wear of the lining, helping to maintain a reasonable furnace shape. A stable and reasonable furnace shape is the foundation for uniform charge distribution, reasonable gas flow distribution, and efficient smelting reactions. Under cooling, the slag inside the furnace condenses on the surface of the cooling wall, forming a "slag skin." This slag skin not only reduces heat transfer to the cooling wall, lowering the cooling load, but also directly blocks the high-temperature gas flow and materials inside the furnace from scouring and eroding the cooling wall itself, forming a virtuous cycle of "slag protecting iron," further enhancing the protective effect on the cooling wall. In summary, through continuous and efficient cooling, the cooling wall ensures safe, stable, and continuous production of the blast furnace under harsh environments of high temperature, high pressure, and strong corrosion. Because the operating conditions of the blast furnace cooling wall are extremely harsh and complex, and the heat load varies greatly between different parts of the blast furnace, the structure and materials of the cooling wall differ significantly between different parts. The hearth area generally uses gray iron flat cast iron cooling walls, while the belly, waist, and body generally use ductile iron cast iron cooling walls with dovetail grooves, with refractory bricks or rammed refractory materials lined within the dovetail grooves.

[0003] The core component of a cast iron cooling wall is the cooling water pipe. The key to the cooling water pipe's performance lies in its selection, bending, and anti-carburization treatment, which directly determine the service life of the cast iron cooling wall. During the use of cast iron cooling walls, the most direct failure mode is leakage from the cooling water pipes, leading to damage and scrapping of the cooling wall, severely limiting its lifespan. There is a need for a cast iron cooling wall with a longer service life for the cooling water pipes. Patents CN219637239U (a blast furnace cast iron cooling wall) and CN223304482U (a blast furnace castable refractories cooling wall) disclose specific structures for cooling walls. However, these structures currently cannot improve the service life of the cooling water pipes. Summary of the Invention

[0004] This invention provides a cooling wall for blast furnaces with a longer service life.

[0005] The purpose of this utility model is achieved in the following way: a cooling wall for a blast furnace, comprising a cooling wall base, wherein cooling water pipes extending out of the cooling wall base at both ends are provided inside the cooling wall base, and the wall thinning caused by bending of the cooling water pipes is ≤15% of the wall thickness.

[0006] The cooling water pipe has a wall thickness of ≥8mm.

[0007] The bending radius R of the cooling water pipe is (1.5~2)D, where D is the outer diameter of the cooling water pipe, and the ellipticity of the bending part is ≤14%; the cooling water pipe is made of 10# seamless steel pipe.

[0008] The cooling wall substrate is a cast iron substrate.

[0009] Protective pipes are provided at both ends of the cooling water pipe extending out of the cooling wall base to protect the cooling water pipe; one end of the protective pipe extends out of the cooling wall and the other end is located in the cooling wall base; a lifting ring is provided at the upper end of the cooling wall base; refractory material is provided on the side of the cooling wall base away from both ends of the cooling water pipe.

[0010] The cooling wall substrate is provided with a dovetail groove on the side away from both ends of the cooling water pipe; the refractory material is laid inside the dovetail groove and on the right side.

[0011] The protective pipe is made of 20# seamless steel pipe; the lifting ring is located at the center of the upper end of the cooling wall base and is made of 20# round steel; the refractory material is sintered microporous alumina-carbon brick, high alumina brick, silicon nitride-bonded silicon carbide brick, silicon carbide ramming material, castable, and steel fiber castable.

[0012] Compared with existing technologies, this invention can effectively extend the service life of cooling water pipes, and thus effectively extend the service life of cooling walls by 2-3 years. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the installation state of this utility model.

[0014] Figure 2 This is a schematic diagram of the present invention.

[0015] Figure 3 yes Figure 2 The left view.

[0016] Figure 4 This is a schematic diagram of the curved section of the cooling water pipe (A is the thinned area).

[0017] The components include: 1. Cooling water pipe; 2. Protective pipe; 3. Cooling wall base; 4. Lifting ring; 5. Dovetail groove; 6. Sealing cover; 7. Furnace shell. Detailed Implementation

[0018] In this utility model, unless otherwise expressly specified and limited, the technical terms used in this application shall have the ordinary meaning understood by those skilled in the art. Terms such as "connected," "linked," "fixed," and "set" shall be interpreted broadly, referring to fixed connections, detachable connections, or integral connections; direct connections or indirect connections via an intermediate medium; mechanical connections or electrical connections. Unless otherwise expressly specified and limited, "above" or "below" a second feature may mean that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," or "over" a second feature may mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," or "under" a second feature may mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature. Relational terms such as "first," "second," etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. The terms used in the description, such as “center,” “lateral,” “longitudinal,” “length,” “width,” “thickness,” “height,” “front,” “rear,” “left,” “right,” “up,” “down,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,” “axial,” “radial,” “circumferential,” “clockwise,” and “counterclockwise,” indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation.

[0019] The technical solution of this utility model will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. Figure 1-4As shown, a cooling wall for a blast furnace includes a cooling wall base 3. Cooling water pipes 1, extending from both ends of the cooling wall base 3, are disposed inside the base 3. The wall thinning caused by bending at the bends of the cooling water pipes 1 is ≤15% of the wall thickness. The cooling water pipes 1 are the core component of the cooling wall and directly determine its service life. Leakage in the cooling water pipes 1 is a common failure mode of cast iron cooling walls. During normal use, the cooling wall is installed and fixed to the furnace shell. The cooling wall is installed inside the blast furnace shell, which is rolled into a frustum shape. Only the cooling water pipe 1 extends outside the furnace shell. The cooling water pipe 1 is fixed to the outside of the furnace shell with a sealing cover. The cooling wall base 3, the cast-in-place cooling water pipe 1, and the protective pipe 2 are all inside the furnace shell. When the cooling wall is in operation, the cooling water pipe 1 inside the furnace shell must withstand the forces of thermal expansion and contraction caused by temperature changes due to furnace condition fluctuations, as well as the scouring of furnace charge, molten slag, iron, and high-temperature airflow after the base material is eroded. The cooling water pipe 1 outside the furnace shell must also withstand the tensile force of the sealing cover. The weakest and most easily damaged part of the entire cooling water pipe 1 is the bent section. In my country's ferrous metallurgical industry standard, section 4.5.5 of the standard for cast iron cooling walls for blast furnaces stipulates that the wall thinning caused by bending should be less than 18% of the wall thickness, depending on the pipe diameter, and the ellipticity of the bent section should be ≤14%. Cooling water pipe 1 needs to be cold-bent from a single steel pipe using a cold bending machine. In this invention, the use of a pipe bending machine and mold ensures that the wall thinning caused by bending of the cooling water pipe 1 is ≤15% of the wall thickness, lower than industry standards. This increases the thickness of the bent portion of the cooling water pipe 1, thereby improving the lifespan of the cooling wall.

[0020] Furthermore, the cooling water pipe 1 has a wall thickness ≥ 8mm. In existing blast furnace cooling walls, the wall thickness of the cooling water pipe 1 is generally around 6mm. This invention uses a rear-wall cooling water pipe 1 with a wall thickness ≥ 8mm. The increased thickness at bends and overall improves the tensile and abrasion resistance of the cooling water pipe 1, particularly noticeable in the later stages of furnace life, effectively extending the service life of the cooling wall by 2-3 years. In this invention, the wall thickness of the cooling water pipe 1 can be 10mm, 15mm, 25mm, etc.

[0021] Preferably, the bending radius R of the cooling water pipe 1 is (1.5~2)D, where D is the outer diameter of the cooling water pipe 1, and the ellipticity of the bent portion is ≤14%; the cooling water pipe 1 is made of 10# seamless steel pipe. The cooling water pipe 1 conforms to GB / T3087 boiler tubes or GB / T8163 seamless steel pipes for fluid transport. Furthermore, the cooling wall substrate 3 is a cast iron substrate. The cooling wall substrate 3 can be made of gray cast iron, preferably HT150; or ductile iron, preferably QT400-20. The cooling wall substrate 3 can also be made of cast steel. Cooling wall substrates 3 made of other materials can also adopt the scheme described in this utility model.

[0022] Specifically, protective pipes 2 are respectively installed at both ends of the cooling water pipe 1 extending out of the cooling wall base 3 to protect the cooling water pipe 1; one end of the protective pipe 2 extends out of the cooling wall and the other end is installed inside the cooling wall base 3; a lifting ring 4 is installed at the upper end of the cooling wall base 3; refractory material is installed on the side of the cooling wall base 3 away from both ends of the cooling water pipe 1. During the casting of the cooling wall base 3, the cooling water pipe 1 and two protective pipes 2 are partially cast into the cooling wall base 3. The protective pipes 2 protect the cooling water pipe 1. The lifting rings 4 are located on the upper surface of the cooling wall base 3, and generally 1-2 are installed depending on the weight. One ring is centered, and two rings are symmetrically arranged around the center. They are made of 20# steel or Q235 round steel, preferably 20# steel, and are partially cast into the cooling wall base 3 during casting.

[0023] Furthermore, a dovetail groove 5 is provided on the side of the cooling wall base 3 away from both ends of the cooling water pipe 1; the refractory material is laid inside and on the right side of the dovetail groove 5. The dovetail groove 5 is part of the cooling wall base 3. The refractory material is disposed on the outside of the cooling wall base 3. Additionally, the right side surface of the cooling wall base 3, i.e., the side away from both ends of the cooling water pipe 1, can also be smooth.

[0024] Preferably, the protective pipe 2 is made of 20# seamless steel pipe; the lifting ring 4 is located at the center of the upper end of the cooling wall base 3 and is made of 20# round steel; the refractory material is sintered microporous alumina-carbon brick, high alumina brick, silicon nitride bonded silicon carbide brick, silicon carbide ramming material, castable, or steel fiber castable.

[0025] The manufacturing process of cast iron cooling walls is as follows: First, model making and bending of cooling water pipe 1 are carried out → shaping and fixing of cooling water pipe 1 and protective pipe 2 are performed → casting of cooling wall base 3 is performed → cleaning and pressure testing are conducted → installation is completed → water supply is initiated. For gray iron materials in cast iron cooling walls, the cooling wall base 3 does not have dovetail grooves 5 and does not require refractory lining. For ductile iron materials, one type of cast iron cooling wall, refractory lining is required both inside and outside the dovetail grooves 5. The cooling water pipe 1, protective pipe 2, and lifting ring 4 must be effectively protected against carburization. The cooling water pipe 1 and sleeve are not fused to the cast iron base, with a gap ≤0.3mm. During installation, the cooling wall base 3 is located inside the furnace shell 7, while part of the protective pipe 2 and the end of the cooling water pipe 1 pass through the furnace shell 7 and are located outside the blast furnace. The protective pipe 2 extends out of the furnace shell 7 and is fitted with a sealing cover 6. These are existing technologies and will not be described in detail further.

[0026] During normal blast furnace production, the furnace temperature is high and fluctuates greatly. The cast iron cooling wall cools the cooling wall base 3 through cooling water pipes 1, which in turn cools the refractory material, ensuring a stable and reasonable furnace shape, protecting the furnace shell, and guaranteeing the safe, smooth, and long-lasting operation of the blast furnace. To achieve this, the cooling water pipes 1 must be durable. Due to the thinning of the wall at gaps and bends, the bends in the cooling water pipes 1 become the weakest point in the blast furnace cast iron cooling wall. This invention addresses this by taking measures in the selection and bending processes of the cooling water pipes 1 to make them more durable and extend their lifespan. This invention uses thick-walled cooling water pipes 1 (wall thickness ≥ 8mm) to construct the cast iron cooling wall, effectively compensating for the shortcomings at bends and improving the cooling strength and erosion resistance of the cooling water pipes 1. During bending, molds are used to ensure that the thinning is ≤ 15% of the wall thickness, effectively extending the service life of the cooling water pipes 1, and consequently extending the service life of the cooling wall by 2-3 years.

[0027] The technical features of the embodiments described above can be combined in any way, and as long as there is no contradiction in the combination of these technical features, they should all be considered within the scope of this specification. Without departing from the overall concept of this utility model, any equivalent substitutions or modifications made to the technical solution of this utility model, as well as any changes and improvements, should also be considered within the protection scope of this utility model.

Claims

1. A cooling wall for a blast furnace, comprising a cooling wall base, wherein cooling water pipes extending out of the cooling wall base at both ends are disposed inside the cooling wall base, characterized in that: At the bends of the cooling water pipe, the wall thinning caused by the bending is ≤ 15% of the wall thickness.

2. The cooling wall for a blast furnace according to claim 1, characterized in that: The cooling water pipe has a wall thickness of ≥8mm.

3. The cooling wall for a blast furnace according to claim 2, characterized in that: The bending radius R of the cooling water pipe is (1.5~2)D, where D is the outer diameter of the cooling water pipe, and the ellipticity of the bending part is ≤14%; the cooling water pipe is made of 10# seamless steel pipe.

4. A cooling wall for a blast furnace according to claim 1, characterized in that: The cooling wall substrate is a cast iron substrate.

5. A cooling wall for a blast furnace according to claim 1, characterized in that: Protective pipes are provided at both ends of the cooling water pipe extending out of the cooling wall base to protect the cooling water pipe; one end of the protective pipe extends out of the cooling wall and the other end is located in the cooling wall base; a lifting ring is provided at the upper end of the cooling wall base; refractory material is provided on the side of the cooling wall base away from both ends of the cooling water pipe.

6. A cooling wall for a blast furnace according to claim 5, characterized in that: The cooling wall substrate is provided with a dovetail groove on the side away from both ends of the cooling water pipe; the refractory material is laid inside the dovetail groove and on the right side.

7. A cooling wall for a blast furnace according to claim 5, characterized in that: The protective pipe is made of 20# seamless steel pipe; the lifting ring is located at the center of the upper end of the cooling wall base and is made of 20# round steel; the refractory material is sintered microporous alumina-carbon brick, high alumina brick, silicon nitride-bonded silicon carbide brick, silicon carbide ramming material, castable, and steel fiber castable.

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