Device and method for transforming an internal combustion hot blast furnace into a top combustion hot blast furnace

Abstract

The invention discloses a device and method for transforming an internal combustion hot blast stove into a top combustion hot blast stove, comprising: a plurality of internal combustion hot blast stoves, arranged on the same straight line and interconnected; a top combustion hot blast stove, arranged in parallel with the internal combustion hot blast stove; a heightened air mixing tank, one end of the heightened air mixing tank being obliquely connected to the top combustion hot blast stove via a hot blast branch pipe, and the other end of the heightened air mixing tank being connected to a plurality of internal combustion hot blast stoves; a first tightening and fixing unit, arranged between the top combustion hot blast stove and the heightened air mixing tank, the first tightening and fixing unit being able to tighten and fix the top combustion hot blast stove and the heightened air mixing tank; a second tightening and fixing unit, arranged between the internal combustion hot blast stove and a hot blast main pipe, the hot blast main pipe being horizontally fixed on one side of the heightened air mixing tank, the second tightening and fixing unit being able to tighten and fix the internal combustion hot blast stove and the hot blast main pipe. The invention achieves good effects such as saving land, saving investment, and shortening switching time.

Description

Technical Field

[0001] The invention relates to the technical field of hot blast stoves, and in particular to a device and method for transforming an internal combustion hot blast stove into a top combustion hot blast stove. Background Art

[0002] The use of high blast temperature in blast furnace ironmaking is the development direction of blast furnace ironmaking technology in the world today. Every 100℃ increase in blast temperature can reduce the coke ratio by 4% to 7%, increase production by 3% to 5%, and allow an increase in coal powder injection of 40kg / t.Fe. After nearly ten years of development, top-fired hot blast furnaces have been increasingly adopted, from a few hundred m 3 To 5000m 3 It is used in all grade blast furnaces.

[0003] There are still a large number of internal combustion hot blast furnaces in my country. The internal combustion hot blast furnace is still the most widely used hot blast furnace. Due to the defects of the traditional internal combustion hot blast furnace, the hot blast temperature is generally not high, and the maintenance is relatively frequent, which cannot meet the needs of blast furnace production. Traditional internal combustion hot blast furnaces have the following common problems:

[0004] 1) The partition wall between the combustion chamber and the heat storage chamber has a large temperature difference on both sides and a serious pulsation phenomenon caused by the use of a sleeve-type metal burner, which causes cracks in the combustion chamber, bricks to fall off, and even short circuits and burns through.

[0005] 2) The structure of the arch located on the large wall is unreasonable, and the arch cracks and damage are caused by the uneven rise and fall of the large wall and its own thermal expansion.

[0006] 3) Hemispherical vault: When high-temperature flue gas enters the checkerboard bricks from the vault, the distribution is very uneven, resulting in local overheating, causing serious burning of the center of the heat storage chamber and poor high-temperature creep performance of the refractory bricks in the high-temperature area of ​​the hot blast furnace, causing the fire well to tilt toward the heat storage chamber and causing disorder of the grid holes.

[0007] 4) As blast furnaces become larger and larger, the wind temperature becomes higher and higher. The hot blast furnace has become a pressure vessel. In addition, the furnace skin of the hot blast furnace rises with the expansion of the refractory masonry, pulling the furnace bottom plate into a "dish" shape, causing the weld to open and the furnace bottom plate to crack, resulting in serious air leakage.

[0008] Due to the above common problems, many internal combustion hot blast furnaces need to be upgraded. Top combustion hot blast furnaces have the following characteristics:

[0009] 1) The top-burning hot blast stove eliminates the side combustion chamber, fundamentally eliminating the fatal shortcomings of the internal combustion hot blast stove.

[0010] 2) Top-fired hot blast furnaces use short-flame burners that burn directly under the dome, reducing heat loss during combustion.

[0011] 3) The top of the top-fired hot blast furnace is a stable and symmetrical structure with a simple furnace shape, good structural strength and uniform force.

[0012] 4) The top-burning hot blast furnace has distinct temperature zones, which improves the working conditions of refractory materials. The lower part has a low working temperature and heavy load, while the upper part has a high working temperature and light load. The working temperature of refractory materials can be appropriately increased and their service life can be extended.

[0013] 5) The top-burning hot blast furnace has a simple furnace shape, is easy to construct, and saves steel and refractory materials.

[0014] Top-fired hot blast stove is the development direction of blast furnace hot blast stove. Summary of the invention

[0015] Based on this, it is necessary to provide a device and method for transforming an internal combustion hot blast stove into a top combustion hot blast stove in order to solve the above technical problems.

[0016] A device for transforming an internal combustion hot blast stove into a top combustion hot blast stove, comprising:

[0017] A plurality of internal combustion hot air furnaces are arranged on the same straight line and are interconnected;

[0018] Top-burning hot blast stoves are arranged in parallel with internal-burning hot blast stoves;

[0019] A heightened air mixing tank, one end of which is obliquely connected to the top-burning hot blast furnace via a hot blast branch pipe, and the other end of which is connected to a plurality of the internal-burning hot blast furnaces;

[0020] A first tightening and fixing unit is arranged between the top-burning hot blast stove and the elevated air mixing tank, and the first tightening and fixing unit can tighten and fix the top-burning hot blast stove and the elevated air mixing tank;

[0021] The second tightening and fixing unit is arranged between the internal combustion hot blast stove and the hot blast main pipe. The hot blast main pipe is horizontally fixed on one side of the elevated air mixing tank. The second tightening and fixing unit can tighten and fix the internal combustion hot blast stove and the hot blast main pipe.

[0022] In one embodiment, the elevated air mixing tank comprises:

[0023] The air mixing tank body has a cavity inside;

[0024] A top-burning air inlet is arranged on the upper side wall of the air mixing tank body and is connected to the cavity. The top-burning air inlet is also obliquely connected to the top-burning hot air furnace via a hot air branch pipe;

[0025] An internal combustion air inlet is arranged on the lower side wall of the air mixing tank body and communicates with the cavity, and the internal combustion air inlet is communicated with the internal combustion hot air furnace;

[0026] An air outlet is arranged on the middle side wall of the air mixing tank body and is connected to the cavity, and the air outlet is also connected to the blast furnace;

[0027] Wherein, there is an angle between the top combustion air inlet and the internal combustion air inlet.

[0028] In one of the embodiments, the first tensioning and fixing unit includes two first large tie rods distributed at an angle, one end of the two first large tie rods is clamped on the outer wall of the furnace shell of the top-fired hot blast furnace, and the other end of the two first large tie rods is clamped on the tank shell of the elevated air mixing tank, wherein the two first large tie rods are oblique to the horizontal line, and the two first large tie rods are respectively located on both sides of the hot blast branch pipe.

[0029] In one of the embodiments, the second tensioning and fixing unit includes two second large tie rods arranged parallel to each other, one end of the two second large tie rods is clamped on the outer wall of the furnace shell of the internal combustion hot blast furnace, and the other end of the two second large tie rods is clamped on the hot blast main pipe, wherein the two second large tie rods are perpendicular to the hot blast main pipe.

[0030] A method for transforming an internal combustion hot blast stove into a top combustion hot blast stove comprises the following steps:

[0031] S1. Build a new top-burning hot blast furnace at the location of multiple internal-burning hot blast furnaces on the same straight line, and arrange the top-burning hot blast furnace and the internal-burning hot blast furnace in parallel;

[0032] S2. Based on the force calculation of the common working conditions of the internal combustion hot blast stove and the top combustion hot blast stove, the original mixing air tank is transformed into a heightened mixing air tank;

[0033] S3, respectively fixing and tightening the heightened air mixing tank to the top-fired hot air stove and the hot air main pipe;

[0034] S4. Remove an internal combustion hot blast furnace and transform it into a top combustion hot blast furnace;

[0035] S5. Repeat step S4 until the transformation of all internal combustion hot blast stoves is completed.

[0036] In one of the embodiments, in step S2, the elevated air mixing tank is raised 33 mm upward relative to the original air mixing tank, the elevated air mixing tank is inclined 6.5 to 10 mm toward the blast furnace and the hot air duct, and its torsion angle is less than 0.1 degrees.

[0037] In one of the embodiments, the step S2 further includes increasing the wall thickness of the lower section of the elevated air mixing tank to 25 mm, and the steel wall material is Q390B.

[0038] The above-mentioned device and method for transforming an internal combustion hot blast furnace into a top-burning hot blast furnace, through the layout and related supporting transformation of the internal combustion hot blast furnaces one by one online into the top-burning hot blast furnace, is designed based on the force calculation guidance of the common working conditions of the internal combustion hot blast furnace and the top-burning hot blast furnace, and some unique arrangements and material selections are adopted in the design, thereby solving the problems encountered in the process of transforming the internal combustion hot blast furnace into the top-burning hot blast furnace. The present invention achieves good effects such as saving land, saving investment, and shortening switching time. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 It is a structural schematic diagram of a device for transforming an internal combustion hot blast furnace into a top combustion hot blast furnace according to the present invention;

[0041] Figure 2 This is a schematic diagram of the structure of the elevated air mixing tank of the present invention from a first angle;

[0042] Figure 3 This is a second angle structural schematic diagram of the heightened air mixing tank of the present invention;

[0043] Figure 4 is a structural schematic diagram of the first tightening and fixing unit of the present invention;

[0044] Figure 5 It is a structural schematic diagram of the second tensioning and fixing unit of the present invention. DETAILED DESCRIPTION

[0045] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Preferred embodiments of the present invention are provided in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0046] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element at the same time.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0048] The main idea of ​​the present invention is:

[0049] A single blast furnace is generally equipped with three hot blast furnaces, which adopt the "two burning and one sending" air supply system. The three hot blast furnaces are arranged in a row, and the three internal combustion hot blast furnaces are converted into top-burning hot blast furnaces. If the blast furnace is shut down for transformation, the construction period will be more than half a year, and the cost is relatively high. Generally, steel companies choose to transform them one by one online, so as to make use of the short time when the blast furnace is shut down for switching. The general idea is to choose an empty space to build a new top-burning hot blast furnace, and then withdraw an internal combustion hot blast furnace for transformation after it is put into use. The transformation process always maintains the "two burning and one sending" air supply system.

[0050] The present invention provides a device and method for transforming an internal combustion hot blast furnace into a top combustion hot blast furnace, including reasonable layout of a new hot blast furnace, design and force calculation of a matching large pull rod, design of a heightened air mixing tank, force calculation of a furnace shell in a common working condition of the internal combustion hot blast furnace and the top combustion hot blast furnace, etc. Compared with other hot blast furnace transformations, the present invention has the characteristics of saving space, saving investment, and shorter switching time.

[0051] See also Figure 1-5 As shown, an embodiment of the present invention provides a device for transforming an internal combustion hot blast stove into a top combustion hot blast stove, comprising:

[0052] A plurality of internal combustion hot blast stoves 1 are arranged on the same straight line and are interconnected. In this embodiment, the number of the internal combustion hot blast stoves 1 is three.

[0053] A top-combustion hot blast stove 2 is arranged in parallel with the internal-combustion hot blast stove 1;

[0054] A heightened air mixing tank 3, one end of which is obliquely connected to the top-burning hot blast furnace 2 via a hot blast branch pipe 6, and the other end of which is connected to a plurality of internal-burning hot blast furnaces 1; in this embodiment, since the hot blast outlet of the top-burning hot blast furnace 2 is more than ten meters higher than the hot blast outlet of the internal-burning hot blast furnace 1, the air mixing tank needs to be heightened and modified to form a heightened air mixing tank 3.

[0055] A first tightening and fixing unit 4 is arranged between the top-burning hot blast stove 2 and the elevated air mixing tank 3, and the first tightening and fixing unit 4 can tighten and fix the top-burning hot blast stove 2 and the elevated air mixing tank 3;

[0056] The second tensioning and fixing unit 5 is arranged between the internal combustion hot blast stove 1 and the hot blast main pipe 7. The hot blast main pipe 7 is horizontally fixed on one side of the elevated air mixing tank 3. The second tensioning and fixing unit 5 can tension and fix the internal combustion hot blast stove 1 and the hot blast main pipe 7.

[0057] In one embodiment of the present invention, the elevated air mixing tank 3 comprises:

[0058] The air mixing tank body 31 has a cavity 32 inside;

[0059] A top-combustion air inlet 33 is provided on the upper side wall of the air mixing tank body 31 and communicates with the cavity 32. The top-combustion air inlet 33 is also obliquely communicated with the top-combustion hot blast furnace 2 via a hot blast branch pipe 6;

[0060] An internal combustion air inlet 34 is provided on the lower side wall of the air mixing tank body 31 and communicates with the cavity 32. The internal combustion air inlet 34 is communicated with the internal combustion hot air furnace 1;

[0061] The air outlet 35 is arranged on the middle side wall of the air mixing tank body 31 and communicates with the cavity 32, and the air outlet 35 is also connected to the blast furnace;

[0062] There is an angle between the top combustion air inlet 33 and the internal combustion air inlet 34 .

[0063] In this embodiment, after a new top-burning hot blast furnace 2 is put into production, the original air mixing tank is raised by more than ten meters to form a raised air mixing tank 3. The hot air of the top-burning hot blast furnace 2 enters the cavity 32 of the air mixing tank body 31 from the upper part of the top-burning air inlet 33 and flows downward; the hot air of the internal combustion hot blast furnace 1 enters the cavity 32 of the air mixing tank body 31 from the lower part of the internal combustion air inlet 34 and flows upward. Finally, the two are mixed and flow out from the air outlet 35 into the blast furnace. The mixing uniformity is good and the impact force is small. At the same time, the top-burning air inlet 33 and the internal combustion air inlet 34 are set to have an angle, which can avoid direct impact between the hot air of the two, thereby further reducing the impact force.

[0064] In one embodiment of the present invention, the first tensioning and fixing unit 4 includes two first large tie rods 41 distributed at an angle, one end of the two first large tie rods 41 is clamped on the outer wall of the furnace shell of the top-fired hot blast furnace 2, and the other end of the two first large tie rods 41 is clamped on the shell of the elevated air mixing tank 3, wherein the two first large tie rods 41 are obliquely intersected with the horizontal line, and the two first large tie rods 41 are respectively located on both sides of the hot blast branch pipe 6. Such a setting can, on the one hand, reduce the space occupancy rate and make the overall structural layout more reasonable and compact; on the other hand, the two first large tie rods 41 are respectively arranged on both sides of the hot blast branch pipe 6, so that the structural strength of the hot blast branch pipe 6 can be guaranteed and the stability of its structure can be improved under the premise of reducing the installation length of the hot blast branch pipe 6 and reducing its installation cost.

[0065] In one embodiment of the present invention, the second tensioning and fixing unit 5 includes two second large tie rods 51 arranged parallel to each other, one end of the two second large tie rods 51 is clamped on the outer wall of the furnace shell of the internal combustion hot blast furnace 1, and the other end of the two second large tie rods 51 is clamped on the hot blast main pipe 7, wherein the two second large tie rods 51 are both perpendicular to the hot blast main pipe 7.

[0066] In this embodiment, the axis of the hot air main pipe 7 is parallel to the same straight line where multiple internal combustion hot air furnaces 1 are located. Therefore, the second large pull rod 51 is vertically tightened to the hot air main pipe 7, and its installation and adjustment are more convenient and simple, and the force is more uniform and constant. At the same time, the overall structural layout is more reasonable and compact.

[0067] An embodiment of the present invention provides a method for transforming an internal combustion hot blast stove into a top combustion hot blast stove, comprising the following steps:

[0068] S1, build a new top-burning hot blast furnace 2 at the location of multiple internal-burning hot blast furnaces 1 on the same straight line, and arrange the top-burning hot blast furnace 2 and the internal-burning hot blast furnace 1 in parallel;

[0069] S2. Based on the force calculation of the common working conditions of the internal combustion hot blast stove 1 and the top combustion hot blast stove 2, the original air mixing tank is transformed into a heightened air mixing tank 3; in addition, the pipes and valves of the hot blast stove system can also be adaptively modified;

[0070] S3, respectively fixing and tightening the heightened air mixing tank 3 to the top-fired hot blast stove 2 and the hot blast main pipe 7;

[0071] S4, withdrawing an internal combustion hot blast furnace 1 and transforming it into a top combustion hot blast furnace 2;

[0072] S5. Repeat step S4 until the transformation of all internal combustion hot blast furnaces 1 is completed, and finally the air supply system of "two burning and one sending" of three top-burning hot blast furnaces is realized.

[0073] It should be noted that after a new top-burning hot blast furnace 2 is built, one of the original three internal-burning hot blast furnaces 1 is withdrawn, forming a working state of one top-burning hot blast furnace 2 plus two internal-burning hot blast furnaces 1.

[0074] The hot air outlet of the top-burning hot blast stove 2 is more than ten meters higher than that of the internal combustion hot blast stove 1. Therefore, when the top-burning hot blast stove 2 delivers air, the hot air enters the upper part of the mixing air tank, then goes down, and flows to the blast furnace after reaching the outlet; while when the internal combustion hot blast stove 1 delivers air, it passes through the hot air main pipe 7 to the lower part of the mixing air tank, then goes up, and flows to the blast furnace after reaching the outlet.

[0075] The entire hot air system has experienced relatively complex stress conditions, including: (1) The direction in which the hot air from the top-burning hot air furnace 2 enters the air mixing tank is at a certain angle (e.g., 120°) to the direction in which the original hot air main pipe 7 enters the air mixing tank, and the air mixing tank is subjected to impact forces from two different directions. (2) The hot air from the top-burning hot air furnace 2 goes downward after entering the air mixing tank, while the hot air from the internal combustion hot air furnace 1 goes upward after entering the air mixing tank, resulting in complex working conditions. Therefore, it is necessary to model and perform stress calculation and analysis on the entire air mixing tank, hot air duct, and large tie rod system.

[0076] Specifically, the results of thermal-mechanical coupling deformation show that the air mixing tank is lifted upward by 33 mm, tilted by 6.5 to 10 mm toward the blast furnace and the hot air branch pipe 6, and the torsion angle is less than 0.1 degrees, forming a heightened air mixing tank 3, and its deformation in the working state is within an acceptable range.

[0077] The maximum stress at the intersection of the air mixing tank and the existing (old) hot air main pipe 7 is 250MPa. The maximum temperature here is 194℃, and the ambient temperature is 131℃. The strength is not satisfied. The old air mixing tank needs to be removed and a new one needs to be built as a whole. The wall thickness of the lower section of the heightened air mixing tank 3 is increased to 25mm. The steel wall material is Q390B, which can guarantee a yield strength of 350MPa at 300℃, meeting the strength requirements.

[0078] In addition, when the overall deformation of the elevated air mixing tank 3 is complex, a bending deformation mode toward the blast furnace and a waist-shaped bending deformation mode appears, which causes axial pressure on the inclined tie rods of the newly built hot air branch pipe 6. The solutions include: adjusting the diameters of the four inclined tie rods, adding a preload adjustment function, and conducting on-site stress testing and tracking.

[0079] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0080] The above-described embodiments only express several implementation methods of the present invention, but they cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A device for transforming an internal combustion hot blast stove into a top combustion hot blast stove, characterized in that: include: A plurality of internal combustion hot air furnaces are arranged on the same straight line and are interconnected; Top-burning hot blast stoves are arranged in parallel with internal-burning hot blast stoves; A heightened air mixing tank, one end of which is obliquely connected to the top-burning hot blast furnace via a hot blast branch pipe, and the other end of which is connected to a plurality of the internal-burning hot blast furnaces; A first tightening and fixing unit is arranged between the top-burning hot blast stove and the elevated air mixing tank, and the first tightening and fixing unit can tighten and fix the top-burning hot blast stove and the elevated air mixing tank; A second tightening and fixing unit is arranged between the internal combustion hot blast stove and the hot blast main pipe, the hot blast main pipe is horizontally fixed to one side of the elevated air mixing tank, and the second tightening and fixing unit can tighten and fix the internal combustion hot blast stove and the hot blast main pipe; The heightened air mixing tank comprises: The air mixing tank body has a cavity inside; A top-burning air inlet is arranged on the upper side wall of the air mixing tank body and is connected to the cavity. The top-burning air inlet is also obliquely connected to the top-burning hot air furnace via a hot air branch pipe; An internal combustion air inlet is arranged on the lower side wall of the air mixing tank body and communicates with the cavity, and the internal combustion air inlet is communicated with the internal combustion hot air furnace; An air outlet is arranged on the middle side wall of the air mixing tank body and is connected to the cavity, and the air outlet is also connected to the blast furnace; Wherein, there is an angle between the top combustion air inlet and the internal combustion air inlet.

2. The device for transforming an internal combustion hot blast stove into a top combustion hot blast stove as claimed in claim 1, characterized in that: The first tensioning and fixing unit includes two first large tie rods distributed at an angle, one end of the two first large tie rods is clamped on the outer wall of the furnace shell of the top-fired hot blast furnace, and the other end of the two first large tie rods is clamped on the tank shell of the elevated air mixing tank, wherein the two first large tie rods are oblique to the horizontal line, and the two first large tie rods are respectively located on both sides of the hot blast branch pipe.

3. The device for transforming an internal combustion hot blast stove into a top combustion hot blast stove as claimed in claim 2, characterized in that: The second tightening and fixing unit includes two second large pull rods arranged parallel to each other, one end of the two second large pull rods is clamped on the outer wall of the furnace shell of the internal combustion hot blast furnace, and the other end of the two second large pull rods is clamped on the hot blast main pipe, wherein the two second large pull rods are both perpendicular to the hot blast main pipe.

4. A method for transforming an internal combustion hot blast stove into a top combustion hot blast stove based on the device for transforming an internal combustion hot blast stove into a top combustion hot blast stove according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Build a new top-burning hot blast furnace at the location of multiple internal-burning hot blast furnaces on the same straight line, and arrange the top-burning hot blast furnace and the internal-burning hot blast furnace in parallel; S2. Based on the force calculation of the common working conditions of the internal combustion hot blast stove and the top combustion hot blast stove, the original mixing air tank is transformed into a heightened mixing air tank; S3, respectively fixing and tightening the heightened air mixing tank to the top-fired hot air stove and the hot air main pipe; S4. Remove an internal combustion hot blast furnace and transform it into a top combustion hot blast furnace; S5. Repeat step S4 until the transformation of all internal combustion hot blast stoves is completed.

5. The method for transforming an internal combustion hot blast stove into a top combustion hot blast stove as claimed in claim 4, characterized in that: In step S2, the elevated air mixing tank is raised 33 mm relative to the original air mixing tank, and the elevated air mixing tank is inclined 6.5 to 10 mm toward the blast furnace and the hot air branch pipe, and its torsion angle is less than 0.1 degrees.

6. The method for transforming an internal combustion hot blast stove into a top combustion hot blast stove as claimed in claim 4, characterized in that: The step S2 also includes increasing the wall thickness of the lower section of the elevated air mixing tank to 25 mm, and the steel wall material is Q390B.

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