Hot air outlet structure and installation method of blast furnace hot blast stove

Abstract

The present invention discloses a hot air outlet structure and an installation method for a blast furnace hot blast stove, relates to the technical field of blast furnace hot air, solves the problems of heating and weld cracking in the existing hot air outlet, and reduces stress concentration. The specific scheme is as follows: it includes an arc-shaped transition steel shell for connecting the hot blast stove shell and the hot air duct, the inner wall of the arc-shaped transition steel shell is evenly fixed with anchor nails and sprayed with paint to form a paint layer, refractory fiber felt is arranged on the inner side of the paint layer, refractory filler is provided on the inner side of the refractory fiber felt, hot air duct insulation bricks and hot air duct working layer bricks are arranged in sequence from the refractory filler to the center line direction of the hot air duct, furnace wall insulation bricks, furnace wall working layer bricks and hot air outlet combination bricks are arranged in sequence from the refractory filler to the inside of the hot blast stove, and the refractory filler is located between the refractory fiber felt and the furnace wall insulation bricks and the hot air duct insulation bricks in the arc-shaped transition area.

Description

Technical Field

[0001] The present invention relates to the technical field of blast furnace hot blast, and in particular to a hot blast outlet structure and an installation method of a blast furnace hot blast stove. Background Art

[0002] As an essential component of the blast furnace ironmaking process, the efficient and stable operation of the hot blast furnace system is essential for ensuring blast furnace production capacity. As the sole channel connecting the blast furnace and the hot blast furnace system and delivering high-temperature air to the blast furnace, the hot blast duct is crucial for maintaining good working condition, especially at vulnerable interface locations such as the hot blast outlet. During the production process, the hot blast furnace alternates air flow, and the hot blast outlet experiences temperature changes as the furnace is fired and the air flow process changes. This in turn causes displacement and stress changes in the steel shell at the hot blast outlet. The existing hot blast outlet interface between the furnace shell and the hot blast duct is connected using fillet welds, and these welds are located in stress-sensitive areas. Repeated thermal effects can easily lead to heating and weld cracking at the interface between the furnace shell and the hot blast duct. This is especially true in some large-scale blast furnace hot blast furnace systems, where temperature and stress changes are more pronounced.

[0003] The inventors discovered that to control the impact of stress on the hot air outlet, existing processes primarily rely on adding stress adjustment devices and reinforcing the interface to control cracking at the interface between the furnace shell and the hot air duct. Common stress adjustment devices include adding large tie rods and compensators, while common interface reinforcements include adding reinforcing plates. To prevent overheating at the hot air outlet, various hot air outlet combination structures and brick layouts have been used. While these combined measures have alleviated hot air outlet heating and cracking to a certain extent, the hot air outlet remains a weak link in the process. The potential for cracking in the fillet weld at the interface between the hot air furnace shell and the hot air duct has not been eliminated, and material usage and costs have also increased. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a hot air outlet structure of a blast furnace hot blast stove, which adopts an arc-shaped transition steel shell to connect the hot blast stove shell and the hot air duct, so that the original fillet weld structure is transformed into a butt weld structure, which can effectively disperse the load, reduce stress concentration, and reduce the amount of material used. In addition, the straight-line distance from the outlet interface weld to the hot air outlet composite brick is significantly increased, which more effectively isolates heat and solves the problems of heating and weld cracking in the existing hot air outlet.

[0005] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0006] In the first aspect, the present invention provides a hot air outlet structure of a blast furnace hot blast stove, comprising an arc-shaped transition steel shell for connecting the hot blast stove shell and the hot air duct, the inner wall of the arc-shaped transition steel shell is evenly fixed with anchor nails and sprayed with paint to form a paint layer, a refractory fiber felt is arranged on the inner side of the paint layer, a refractory filler is provided on the inner side of the refractory fiber felt, hot air duct insulation bricks and hot air duct working layer bricks are arranged in sequence from the refractory filler to the center line of the hot air duct, furnace wall insulation bricks, furnace wall working layer bricks and hot air outlet combination bricks are arranged in sequence from the refractory filler to the inside of the hot blast stove, and the refractory filler is located between the refractory fiber felt and the furnace wall insulation bricks and the hot air duct insulation bricks in the arc-shaped transition area.

[0007] As a further implementation, the circumferential radius chamfers of the arc-shaped transition steel shells are all the same.

[0008] As a further implementation, the arc-shaped transition steel shell is composed of at least one arc plate, and the connecting welds between two adjacent arc plates are symmetrically distributed along the plane where the hot blast stove axis is located and the plane where the hot blast duct axis is located.

[0009] As a further implementation, the weld is not provided at the intersection of the arc plate and the vertical plane where the axis of the hot blast stove is located.

[0010] As a further implementation, the thickness of the refractory fiber felt above the center line of the hot air outlet along the arc transition direction of the arc-shaped transition steel shell is greater than the thickness below the center line.

[0011] As a further implementation method, the thickness of the furnace wall insulation bricks arranged above the center line of the hot air outlet is thinner than that arranged below the center line.

[0012] As a further implementation method, the hot air outlet combined bricks adopt a rounded transition at the right angle position of the hot air outlet.

[0013] As a further implementation, the furnace wall insulation bricks and the hot air duct insulation bricks are both composed of single or multiple layers of insulation bricks of different types.

[0014] In a second aspect, the present invention provides a method for installing a hot air outlet structure of a blast furnace hot blast stove, which is as follows:

[0015] Make an arc-shaped transition steel shell, butt-weld the arc-shaped transition steel shell to the hot blast furnace shell, and then butt-weld the arc-shaped transition steel shell to the hot blast duct, and evenly weld anchor nails inside the arc-shaped transition steel shell;

[0016] The inner wall of the arc-shaped transition steel shell is sprayed to form a coating layer. After the spraying is completed, the refractory fiber felt, refractory filling material, furnace wall insulation bricks, furnace wall working layer bricks, hot air duct insulation bricks, hot air duct working layer bricks and hot air outlet combination bricks are constructed in the order of the lower half ring first and the upper half ring.

[0017] As a further implementation method, first install the lower half ring of refractory fiber felt, and support the lower half ring of the hot air duct with formwork. After the formwork is completed, pour the refractory filling material. After the refractory filling material is formed, remove the formwork and lay the hot air duct insulation bricks, hot air duct working layer bricks, hot air outlet combination bricks, and furnace wall insulation bricks and furnace wall working layer bricks below the center line of the hot air duct.

[0018] After the lower half ring is completed, the refractory fiber felt is laid to fix the upper half ring, and then the furnace wall insulation bricks and furnace wall working layer bricks of the upper half ring are laid. After the masonry is completed, the refractory filling material at the upper half ring is poured.

[0019] The beneficial effects of the present invention are as follows:

[0020] (1) The present invention adopts an arc-shaped transition steel shell to connect the hot blast furnace shell and the hot blast duct, so that the original fillet weld structure is transformed into a butt weld structure, which can effectively disperse the load, reduce stress concentration, and reduce the amount of material used. In addition, the straight-line distance from the outlet interface weld to the hot blast outlet composite brick is significantly increased, which can more effectively isolate heat and reduce the temperature of the outer surface of the hot blast outlet.

[0021] (2) The thickness of the refractory fiber felt of the present invention along the arc transition direction of the arc-shaped transition steel shell above the center line of the hot air outlet is greater than the thickness below the center line, and the corresponding furnace wall insulation bricks are arranged above the center line of the hot air outlet with a thickness less than the thickness below the center line, thereby reducing the weight of the refractory material above the center line of the hot air duct, reducing the load, and further enhancing the thermal insulation effect, which can more effectively reduce the temperature of the outer surface of the interface.

[0022] (3) The hot air outlet composite bricks of the present invention adopt rounded corner transition at the right angle position of the hot air outlet, which greatly improves the uniformity of gas flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0024] Figure 1 is a schematic cross-sectional view of a hot air outlet structure of a blast furnace hot blast stove according to one or more embodiments of the present invention;

[0025] Figure 2 This is a schematic front view of a hot air outlet structure of a blast furnace hot blast stove according to one or more embodiments of the present invention;

[0026] Figure 3 is a schematic diagram of the three-dimensional structure of a curved transition steel shell according to one or more embodiments of the present invention;

[0027] Figure 4 is a schematic front view of the structure of a curved transition steel shell according to one or more embodiments of the present invention;

[0028] In the figure: the distances or sizes between parts are exaggerated to show the positions of the parts, and the diagram is for illustration only;

[0029] Among them, 1. Arc-shaped transition steel shell; 101. First arc plate; 102. Second arc plate; 103. Third arc plate; 2. Coating layer; 3. Refractory fiber felt; 4. Refractory filler; 5. Furnace wall insulation bricks; 6. Furnace wall working layer bricks; 7. Hot air duct insulation bricks; 8. Hot air duct working layer bricks; 9. Hot air outlet combination bricks; 10. Interface weld; 11. Hot air furnace shell; 12. Hot air duct. DETAILED DESCRIPTION

[0030] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0031] As introduced in the background technology, although the heating and cracking of the hot air outlet have been alleviated to a certain extent through the combined use of multiple measures, the hot air outlet is still a weak link in the process. The hidden danger of cracking of the corner weld at the interface between the hot blast furnace shell and the hot air duct has not been eliminated. At the same time, the material consumption is increased and the cost investment is increased. In order to solve the above technical problems, the present invention proposes a hot air outlet structure and installation method for a blast furnace hot blast furnace.

[0032] Example 1

[0033] In a typical embodiment of the present invention, Figure 1-Figure 4 As shown, a hot air outlet structure of a blast furnace hot blast stove is proposed, including an arc-shaped transition steel shell 1 for connecting the hot blast stove shell 11 and the hot air duct 12, the circumferential curvature of the arc-shaped transition steel shell 1 changes uniformly, the inner wall of the arc-shaped transition steel shell 1 is welded with evenly arranged anchor nails and sprayed with paint to form a paint layer 2, the anchor nails are mainly used to improve the connection strength between the paint layer 2 and the arc-shaped transition steel shell 1, a refractory fiber felt 3 is arranged on the inner side of the paint layer 2 (the side away from the arc-shaped transition steel shell 1), a refractory filler 4 is provided on the inner side of the refractory fiber felt 3, and a hot air duct insulation brick 7 and a hot air duct working layer brick 8 are arranged in sequence from the refractory filler 4 to the center line direction of the hot air duct 12, and a furnace wall insulation brick 5, a furnace wall working layer brick 6 and a hot air outlet combination brick 9 are arranged in sequence from the refractory filler 4 to the direction inside the hot blast stove, and the refractory filler 4 is located between the refractory fiber felt 3 and the furnace wall insulation brick 5 and the hot air duct insulation brick 7 in the arc-shaped transition area.

[0034] Specifically, a coating layer 2, a refractory fiber felt 3, a refractory filler 4, a hot air duct insulation brick 7, and a hot air duct working layer brick 8 are arranged in sequence from the inner wall of the arc-shaped transition steel shell 1 to the center line of the hot air duct 12; a coating layer 2, a refractory fiber felt 3, a refractory filler 4, a furnace wall insulation brick 5, a furnace wall working layer brick 6 and a hot air outlet combination brick 9 are arranged in sequence from the inner wall of the arc-shaped transition steel shell 1 to the inside of the hot air furnace, and the hot air duct insulation brick 7, the hot air duct working layer brick 8 and the furnace wall insulation brick 5, the furnace wall working layer brick 6 are connected through the hot air outlet combination brick 9.

[0035] The arc-shaped transition steel shell 1 is composed of at least one arc plate, which is a steel structure. When composed of multiple arc plates, the connecting welds of two adjacent arc plates should be symmetrically distributed along the plane where the hot blast stove axis is located (vertical) and the plane where the hot blast duct 12 axis is located (horizontal), and avoid arranging welds at the intersection of the vertical plane where the arc plate and the hot blast stove axis are located (here is the position where the displacement and stress change the most), so as to reduce the influence of the displacement and stress changes caused by the alternation of the furnace firing and air supply processes on the welds of the arc-shaped transition steel shell 1.

[0036] Compared with the existing technology that adds large-diameter hot air duct short-circuit and reinforcement plate to avoid cracking of the interface weld 10, the arc interface reduces the use of hot air duct steel, insulation bricks and other materials, reduces the pipeline load and effectively reduces material costs.

[0037] For ease of explanation, this embodiment is described using three groups (six pieces) of arc plates as an example. The arc-shaped transition steel shell 1 is composed of two first arc plates 101, two second arc plates 102, and two third arc plates 103. The single first arc plate 101, the second arc plate 102, and the third arc plate 103 are arranged in sequence along the circumferential direction of the hot air outlet. The welds connecting the two adjacent arc plates are symmetrically distributed along the plane where the axis of the hot blast furnace and the axis of the hot air duct 12 are located. No welds are arranged at the intersection of the plane where the axis of the hot blast furnace is located (i.e., the vertical plane) and the arc-shaped transition steel shell 1 to reduce the influence of displacement and stress changes caused by the alternation of furnace firing and air supply processes on the welds.

[0038] The arc-shaped transition steel shell 1 adopts the same radius chamfer in the circumference, and the chamfer size is 0.4m≤r≤1.2m, so that the upper and lower sections of the hot air outlet (i.e. the highest and lowest points of the hot air outlet in the vertical direction) have a larger arc length, so as to better adapt to the stress distribution at the hot air outlet position.

[0039] The arc-shaped transition steel shell 1 is a prefabricated part with high flexibility in use. The straight-line distance from the hot air outlet interface weld 10 or the arc-shaped transition steel shell 1 to the hot air outlet composite brick 9 is significantly increased compared with the straight-line distance from the hot air outlet interface weld 10 to the hot air outlet composite brick in the prior art, which can more effectively isolate heat and reduce the outer surface temperature of the hot air outlet.

[0040] The interface between the hot blast furnace shell 11 and the hot blast duct 12 is connected by a prefabricated arc plate, which transforms the original fillet weld structure into a butt weld structure, has stronger deformation resistance and better mechanical properties, plays a good transition role, can effectively disperse the load, reduce stress concentration, make the structure more solid and reliable, avoid stress concentration at the fillet weld interface between the furnace shell and the hot blast duct, increase the toughness of the interface, and effectively solve the problem of cracking at the hot blast outlet interface.

[0041] Different types of refractory fillers 4 can be selected for the upper and lower half rings of the hot air duct 12 (i.e., the hot air duct 12 is located in the upper half of the axis and the lower half of the axis), so that the lower half ring has better forming ability and structural stability, and the upper half ring has lighter weight and better thermal insulation effect.

[0042] Between the hot blast stove body and the hot blast outlet, the thickness of the refractory fiber felt 3 arranged above the center line of the hot blast outlet along the arc transition direction of the arc-shaped transition steel shell 1 is greater than the thickness arranged below the center line, and the corresponding furnace wall insulation bricks 5 are arranged above the center line of the hot blast outlet with a thickness less than the thickness arranged below the center line, thereby reducing the weight of the refractory material above the center line of the hot blast duct 12, reducing the load, and further enhancing the thermal insulation effect, which can more effectively reduce the temperature of the outer surface of the interface.

[0043] The hot air outlet combined bricks 9 adopt rounded transition at the right angle position of the hot air outlet to improve the uniformity of gas flow. The furnace wall insulation bricks 5 and the hot air duct insulation bricks 7 can be composed of single or multiple layers of different types of insulation bricks.

[0044] Example 2

[0045] In another typical embodiment of the present invention, a method for installing a hot air outlet structure of a blast furnace hot blast stove is proposed, which is specifically as follows:

[0046] The production of the arc-shaped transition steel shell 1: The composition structure of the arc-shaped transition steel shell 1 is divided according to the hot air outlet size and actual processing capacity. The arc-shaped transition steel shell 1 adopts the same radius chamfer in the circumference. Figure 3 and Figure 4 Taking a six-arc plate structure as an example, the arc plates are divided into three specifications, namely the first arc plate 101, the second arc plate 102, and the third arc plate 103. The single first arc plate 101, the second arc plate 102, and the third arc plate 103 are arranged in sequence along the circumferential direction of the hot air outlet. The connecting welds of two adjacent arc plates are symmetrically distributed along the plane where the axis of the hot air stove and the axis of the hot air duct 12 are located. No weld is arranged at the intersection of the plane where the axis of the hot air stove and the arc-shaped transition steel shell 1 to reduce the influence of displacement and stress changes caused by the alternation of furnace firing and air supply processes on the welds. After the division is completed, the arc plates are processed and formed using process measures;

[0047] The arc-shaped transition steel shell 1 composed of multiple arc plates is assembled and welded in the processing plant. The welds are welded symmetrically along the circumference of the steel shell. After welding, stress relief annealing is optionally performed. After annealing, the dimensions are measured and the components are polished and finished.

[0048] Installation of the arc-shaped transition steel shell 1: An interface of the arc-shaped transition steel shell 1 is reserved on the installed hot blast furnace shell 11. The arc-shaped transition steel shell 1 is first butt-welded to the hot blast furnace shell 11. After welding is completed, the arc-shaped transition steel shell 1 is butt-welded to the hot blast duct 12. Anchor nails are evenly arranged inside the arc-shaped transition steel shell 1.

[0049] Spraying of the arc-shaped transition steel shell 1 and construction of the furnace wall: The inner wall of the arc-shaped transition steel shell 1 is sprayed to form a coating layer 2. The coating layer 2 can be selected from acid-resistant spray coatings or other types of spray coatings as needed. After the spraying is completed, the refractory fiber felt 3, refractory filler 4, furnace wall insulation bricks 5, furnace wall working layer bricks 6, hot air duct insulation bricks 7, hot air duct working layer bricks 8 and hot air outlet combination bricks 9 are constructed in the order of the lower half ring first and the upper half ring. Among them, the refractory filler 4 is a castable.

[0050] The specific construction process of the upper and lower half rings is as follows: first, the lower half ring of refractory fiber felt 3 is laid and fixed, and the lower half ring of the hot air duct 12 is supported by formwork. After the formwork is completed and firmly fixed, the refractory filling material 4 is poured. After the refractory filling material 4 is formed, the formwork is removed and the hot air duct insulation bricks 7, the hot air duct working layer bricks 8, the hot air outlet combination bricks 9, and the furnace wall insulation bricks 5 and the furnace wall working layer bricks 6 below the center line of the hot air duct 12 are laid. The pouring-before-laying method can fill and support the furnace wall insulation bricks 5 and the furnace wall working layer bricks 6, thereby avoiding the problem of the furnace wall insulation bricks 5 and the furnace wall working layer bricks 6 falling due to lack of support during the laying process.

[0051] After the construction of the lower half ring is completed, the refractory fiber felt 3 of the upper half ring is laid and fixed, and then the furnace wall insulation bricks 5 and the furnace wall working layer bricks 6 of the upper half ring are laid to a position close to the upper end of the refractory filling material 4 to be poured, and then the construction of the upper half ring of the refractory filling material 4 is carried out. The method of laying first and then pouring eliminates the formwork operation of the upper half ring, which greatly improves the construction efficiency.

[0052] It can be understood that different types of refractory fillers 4 can be selected for the upper and lower half rings of the hot air duct 12, so that the lower half ring has better forming ability and structural stability, and the upper half ring has lighter weight and better thermal insulation effect. It can be constructed in multiple sections and multiple times according to the selected filler type and process requirements. Prefabricated refractory materials can also be used to be simultaneously laid and formed with the working layer bricks and the insulation layer bricks for filling, or a combination of shaped materials and unshaped materials can be used for filling. The specific details can be determined according to actual needs, and there are no excessive restrictions here.

[0053] Among them, the hot air outlet combined bricks 9 adopt arc transition at the right angle position of the hot air outlet to improve the uniformity of gas flow. The furnace wall insulation bricks 5 and the hot air duct insulation bricks 7 can be composed of single or multiple layers of different types of insulation bricks;

[0054] The thickness of the refractory fiber felt 3 above the center line of the hot air outlet along the arc transition direction of the hot air furnace body and the hot air outlet is greater than the thickness below the center line. The corresponding furnace wall insulation bricks 5 are arranged with a thickness above the center line of the hot air outlet less than the thickness below the center line, thereby reducing the weight of the refractory material above the center line of the hot air duct, reducing the load and further enhancing the insulation effect.

[0055] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A hot air outlet structure for a blast furnace hot blast stove, characterized in that: It includes an arc-shaped transition steel shell for connecting the hot blast furnace shell and the hot blast duct. Anchor nails are evenly fixed on the inner wall of the arc-shaped transition steel shell and a coating is sprayed to form a coating layer. Refractory fiber felt is arranged on the inner side of the coating layer. Refractory filler is provided on the inner side of the refractory fiber felt. Hot blast duct insulation bricks and hot blast duct working layer bricks are arranged in sequence from the refractory filler toward the center line of the hot blast duct. Furnace wall insulation bricks, furnace wall working layer bricks and hot blast outlet combination bricks are arranged in sequence from the refractory filler toward the inside of the hot blast furnace. The refractory filler is located between the refractory fiber felt and the furnace wall insulation bricks and the hot blast duct insulation bricks in the arc-shaped transition area. The arc-shaped transition steel shell is composed of at least one arc plate, and the connecting welds between two adjacent arc plates are symmetrically distributed along the plane where the hot blast stove axis is located and the plane where the hot blast duct axis is located; The thickness of the refractory fiber felt above the center line of the hot air outlet along the arc transition direction of the arc-shaped transition steel shell is greater than the thickness below the center line; The thickness of the furnace wall insulation bricks arranged above the center line of the hot air outlet is smaller than the thickness arranged below the center line.

2. The hot air outlet structure of a blast furnace hot blast stove according to claim 1, characterized in that: The circumferential radius chamfers of the arc-shaped transition steel shells are all the same.

3. The hot air outlet structure of a blast furnace hot blast stove according to claim 1, characterized in that: The welding seam is not arranged at the intersection position of the arc plate and the vertical plane where the axis of the hot blast stove is located.

4. The hot air outlet structure of a blast furnace hot blast stove according to claim 1, characterized in that: The hot air outlet combined bricks adopt a rounded transition at the right angle position of the hot air outlet.

5. The hot air outlet structure of a blast furnace hot blast stove according to claim 1, characterized in that: The furnace wall insulation bricks and the hot air duct insulation bricks are both composed of single-layer or multi-layer insulation bricks of different types.

6. A method for installing a hot air outlet structure of a blast furnace hot blast stove according to any one of claims 1 to 5, characterized in that: The details are as follows: Make an arc-shaped transition steel shell, butt-weld the arc-shaped transition steel shell to the hot blast furnace shell, and then butt-weld the arc-shaped transition steel shell to the hot blast duct, and evenly weld anchor nails inside the arc-shaped transition steel shell; The inner wall of the arc-shaped transition steel shell is sprayed to form a coating layer. After the spraying is completed, the refractory fiber felt, refractory filling material, furnace wall insulation bricks, furnace wall working layer bricks, hot air duct insulation bricks, hot air duct working layer bricks and hot air outlet combination bricks are constructed in the order of the lower half ring first and the upper half ring.

7. The method for installing a hot air outlet structure of a blast furnace hot blast stove according to claim 6, characterized in that: First, install the lower half ring of refractory fiber felt, and support the formwork of the lower half ring of the hot air duct. After the formwork is completed, pour the refractory filling material. After the refractory filling material is formed, remove the formwork and lay the hot air duct insulation bricks, hot air duct working layer bricks, hot air outlet combination bricks, and furnace wall insulation bricks and furnace wall working layer bricks below the center line of the hot air duct; After the lower half ring is completed, the refractory fiber felt is laid to fix the upper half ring, and then the furnace wall insulation bricks and furnace wall working layer bricks of the upper half ring are laid. After the masonry is completed, the refractory filling material at the upper half ring is poured.

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