Novel blast furnace hot air pipeline expansion gap arrangement

Abstract

The utility model relates to the technical field of blast furnace hot air pipelines, in particular to a novel blast furnace hot air pipeline expansion joint device which comprises a hot air pipeline, a heavy high-alumina brick, a light heat insulation brick and an expansion joint body. The hot air pipeline working layer is made of high aluminum, and two layers of heat insulation bricks are laid on the hot air pipeline working layer and are respectively heavy high aluminum bricks and light heat insulation bricks. The working layer of the heavy high-alumina brick is provided with an expansion joint body along the axial direction according to the length of 4mm per meter, and the light heat-insulating brick is not provided with an expansion joint body in the axial direction and the radial direction; the heavy high-alumina bricks and the light heat-insulating bricks are sequentially distributed from inside to outside along the inner diameter; the length of the hot air pipeline is 10m, the length of the heavy high-alumina brick is 300mm / block, and the length of the light heat-insulating brick is 230mm / block. The novel blast furnace hot air pipeline expansion joint is arranged, so that the generation of pressure fracture or cracks of the bricks can be greatly inhibited, the overall strength of a masonry is enhanced, the sealing performance is improved, the pig iron cost is greatly reduced, and manpower and financial resources are greatly saved.

Description

Technical Field

[0001] The utility model relates to the technical field of blast furnace hot air pipelines, in particular to a novel expansion joint arrangement of blast furnace hot air pipelines. Background Art

[0002] The inner wall of the hot air duct of the blast furnace is made of heat-resistant materials. In long-term production, due to the constant change of hot air temperature, the heat-resistant material will expand and contract, thus generating thermal stress. For this reason, when designing the hot air duct, expansion joints are usually set to absorb these thermal stresses, which can not only maintain the sealing of the duct, but also prevent structural damage caused by expansion. If the expansion joint is not properly located or is not wide enough, it may cause the bricks to break or crack under pressure; on the contrary, if the expansion joint is too wide, it will weaken the overall strength of the masonry and reduce the sealing.

[0003] For example, the hot air duct masonry structure of the hot blast furnace provided by the Chinese utility model patent with application number CN201520619610.X includes a three-layer structure, which is a working layer, a thermal insulation layer, and a spray layer from the outside to the inside, and an expansion joint is arranged between the working layer and the thermal insulation layer. The utility model hot air duct masonry structure of the hot blast furnace of the hot blast furnace sets the expansion joint between the thermal insulation layer and the working layer so that the thermal expansion of the hot air duct working layer can be effectively absorbed without damaging the thermal insulation layer, and is a stable and effective blast furnace hot air duct masonry structure.

[0004] Another example:

[0005] A method for setting expansion joints on the top of a fixed anode furnace provided by a Chinese utility model patent with application number CN202311005758.X;

[0006] A blast furnace upper body lining structure provided by the Chinese utility model patent application number CN201020146974.8;

[0007] A Chinese utility model patent with application number CN201520869341.2 provides a ring-fork masonry ultra-high temperature hot blast furnace hot blast duct;

[0008] The Chinese utility model patent with application number CN202010571412.6 provides a thermal stress calculation method and system for the longevity of the blast furnace hearth.

[0009] In the past, the design method of expansion joints was mainly based on the calculation and determination of the linear expansion coefficient of refractory materials, which usually depends on the material properties and the maximum operating temperature. For example, if high-aluminum refractory bricks are used, the expansion joint per meter length is recommended to be set to 7-8mm. However, in actual applications, it is found that this method sometimes causes the expansion joint to be too wide, causing air leakage, abnormal temperature rise and even discoloration in the pipeline, indicating design defects.

[0010] In order to more accurately control the size of the expansion joint, it is necessary to consider a variety of factors, including the thermal expansion characteristics of the masonry itself, the linear change after repeated heating, and the shrinkage rate of the refractory mud. Through an in-depth analysis of the problems of traditional practices, an improved expansion joint design scheme was proposed based on this, aiming to optimize the hot air duct structure and ensure its long-term stable operation. Utility Model Content

[0011] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the utility model is to provide a method for setting expansion joints suitable for the longevity and safety of blast furnace hot blast ducts, which method has good effects when applied in actual production.

[0012] The purpose of this utility model is achieved through the following technical solutions:

[0013] The working layer of the hot air duct of the utility model is made of high alumina, and two layers of insulation bricks are applied, namely heavy high alumina bricks and light insulation bricks. In the actual masonry process, the working layer of the heavy high alumina bricks is provided with an expansion joint body at 4 mm per meter along the axial direction, and the light insulation bricks are not provided with an expansion joint body in the axial and radial directions.

[0014] The thermal expansion requirements of this utility model are: under the condition of 20~1200℃, the average linear expansion coefficient of heavy high alumina brick is 6.5×10 -6 ℃ -1 , then the axial expansion size of the hot air duct per meter is 6.5×10 -6 ×1000×(1200-20)=7.67mm. Therefore, a 10m long hot air duct will expand by 7.67×10=76.7mm.

[0015] The re-firing line change requirement of the utility model is: the re-firing line change of the heavy high-alumina brick is -0.2%, and the re-firing line change of the hot air duct per meter length is -0.2%×1000=-2mm. Therefore, the 10m long hot air duct will produce a -2×10=-20mm contraction in the axial direction.

[0016] The requirements for the refractory slurry of the utility model are: when a single brick with a length of 300mm is used to build a 10m long hot air duct working layer, 33 brick joints will be generated along the axial direction of the hot air duct. When each brick joint is calculated as 3mm, the total length of the brick joints is: 33×3=99mm, and the slurry shrinkage is calculated as 15%, which results in a shrinkage of 99×15%≈15mm.

[0017] In summary, when the working layer bricks of the hot air duct are built with heavy high-alumina bricks, the expansion joint left along the axial direction of the 10m long hot air duct should be: 76.7-20-15=41.7mm, that is to say, an expansion joint body of about 4mm is left for each meter of the hot air duct, which is about half shorter than the traditional expansion joint body of 7~8mm left along the axial direction for each meter of the hot air duct.

[0018] Compared with the prior art, the beneficial effects of the utility model are:

[0019] 1. The expansion joint arrangement of the hot air duct of a blast furnace provided by the utility model can greatly suppress the occurrence of pressure cracks or cracks in bricks.

[0020] 2. The expansion joint arrangement of the blast furnace hot air duct provided by the utility model can enhance the overall strength of the masonry and improve the sealing performance.

[0021] 3. The expansion joint arrangement of the blast furnace hot blast duct provided by the utility model can significantly reduce the cost of pig iron and greatly save manpower and financial resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of optimizing the local expansion joint of the cross section of the blast furnace hot air duct of the utility model.

[0023] In the figure:

[0024] 1. Heavy high-alumina bricks; 2. Lightweight insulation bricks; 3. Expansion joint body. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0026] The specific implementation of the utility model is described below in conjunction with the accompanying drawings:

[0027] like Figure 1 As shown, the utility model includes a hot air duct, a heavy high-aluminum brick 1, a lightweight insulation brick 2 and an expansion joint body 3; the working layer of the hot air duct is made of high-aluminum, and two layers of insulation bricks are applied, namely the heavy high-aluminum brick 1 and the lightweight insulation brick 2; the working layer of the heavy high-aluminum brick 1 is provided with an expansion joint body 3 at 4 mm per meter along the axial direction, and the lightweight insulation brick 2 is not provided with an expansion joint body 3 in the axial and radial directions.

[0028] like Figure 1As shown, the utility model comprises heavy high-alumina bricks 1 and light insulation bricks 2 from inside to outside along the inner diameter.

[0029] The length of the hot air duct is 10m, the length of the heavy high-alumina brick 1 is 300mm / piece, and the length of the lightweight insulation brick 2 is 230mm / piece.

[0030] At 20~1200℃, the average linear expansion coefficient of heavy high alumina brick is 6.5×10 -6 ℃ -1 , then the axial expansion size of the hot air duct per meter is 6.5×10 -6 ×1000×(1200-20)=7.67mm. Therefore, a 10m long hot air duct will produce an expansion of 7.67×10=76.7mm. This can greatly inhibit the occurrence of bricks under pressure cracking or cracks.

[0031] The reburning line change of heavy high-alumina bricks is -0.2%, and the reburning line change of each meter of hot air duct is -0.2%×1000=-2mm. Therefore, a 10m long hot air duct will shrink by -2×10=-20mm in the axial direction. It can enhance the overall strength of the masonry and improve the sealing.

[0032] When a single brick with a length of 300mm is used to build a 10m long hot air duct working layer, 33 brick joints will be generated along the axial direction of the hot air duct. When each brick joint is calculated as 3mm, the total length of the brick joint is: 33×3=99mm. If the slurry shrinks by 15%, it will produce a shrinkage of 99×15%≈15mm. This can greatly reduce the cost of pig iron and greatly save manpower and financial resources.

[0033] During the masonry process, the masonry accuracy and dimensional error of the refractory bricks should be ensured to be within the allowable range to avoid inaccurate size of the expansion joint body 3 due to construction errors; during use, the expansion joint body 3 of the heavy high-alumina bricks 1 and the lightweight insulating bricks 2 should be regularly inspected and maintained to ensure that they are in good condition and that potential problems can be discovered and handled in a timely manner.

[0034] The above is the working process of the entire device, and the contents not described in detail in this specification belong to the existing technology known to professional and technical personnel in this field.

[0035] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A new expansion joint arrangement for hot blast duct of blast furnace, characterized in that: The invention comprises a hot air duct, heavy high-aluminum bricks (1), lightweight heat-insulating bricks (2) and an expansion joint body (3); the working layer of the hot air duct is made of high-aluminum material, and two layers of heat-insulating bricks are applied, namely, heavy high-aluminum bricks (1) and lightweight heat-insulating bricks (2); the working layer of the heavy high-aluminum bricks (1) is provided with an expansion joint body (3) at a rate of 4 mm per meter along the axial direction, and the lightweight heat-insulating bricks (2) are not provided with an expansion joint body (3) in the axial direction or in the radial direction.

2. A novel expansion joint arrangement for hot blast duct of blast furnace according to claim 1, characterized in that: The heavy high-alumina bricks (1) and the light insulation bricks (2) are distributed in sequence from the inside to the outside along the inner diameter.

3. A novel expansion joint arrangement for hot blast duct of blast furnace according to claim 2, characterized in that: The length of the hot air duct is 10m, the length of the heavy high-alumina brick (1) is 300mm / piece, and the length of the lightweight insulation brick (2) is 230mm / piece.

4. A novel expansion joint arrangement for hot blast duct of blast furnace according to claim 3, characterized in that: At 20-1200°C, the average linear expansion coefficient of the heavy high-alumina brick is 6.5×10 -6 ℃ -1 , then the axial expansion size of the hot air duct per meter is 6.5×10 -6 ×1000×(1200-20)=7.67mm, therefore, a 10m long hot air duct will produce an expansion of 7.67×10=76.7mm.

5. A novel expansion joint arrangement for hot blast duct of blast furnace according to claim 4, characterized in that: The re-firing line change of the heavy high-alumina brick is -0.2%, and the re-firing line change of the hot air duct per meter length is -0.2%×1000=-2mm. Therefore, the 10m long hot air duct will shrink by -2×10=-20mm in the axial direction.

6. A novel expansion joint arrangement for hot blast duct of blast furnace according to claim 1, characterized in that: When a single brick with a length of 300mm is used to build a 10m long hot air duct working layer, 33 brick joints will be produced along the axial direction of the hot air duct. When each brick joint is calculated as 3mm, the total length of the brick joints is: 33×3=99mm. If the mud shrinkage is calculated as 15%, the shrinkage will be 99×15%≈15mm.

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