A method of repairing a converter flue

Abstract

The application discloses a converter flue repairing method, which comprises the following steps: firstly, cutting the seriously damaged part of the flue; then, installing a heat pipe with the same length as the cut part to the flue cut part, and welding the heat pipe to the flue; finally, sealing the gap between the heat pipes. The converter flue repairing method disclosed by the application cuts the seriously damaged part as a whole, and replaces the whole part with a new heat pipe, so that the hidden danger of the old pipe corrosion is fundamentally eliminated. The application adopts the heat pipe (i.e. evaporation heat surface pipe material) as a replacement part instead of a common steel pipe. The heat pipe itself is a component of the flue evaporation cooling system, and has good high-temperature resistance.

Description

Technical Field

[0001] This application belongs to the field of flue gas repair technology, specifically relating to a method for repairing converter flues. Background Technology

[0002] The converter tail flue has been operating under high temperature and humidity conditions for a long time. During the smelting process, the flue gas flow continuously erodes the flue, causing severe corrosion and wear on the densely packed pipe walls, and frequent water leakage, which poses a major hidden danger to the safe smelting of the converter.

[0003] Currently, the main online repair methods for addressing flue gas leakage have at least the following drawbacks: after patching the leak, other pipes are used to seal it. However, leaks reappear in other areas shortly afterward, resulting in frequent repairs and poor effectiveness. Summary of the Invention

[0004] To solve the above-mentioned technical problems, this application discloses a method for repairing converter flue.

[0005] The technical solution adopted to achieve the purpose of this application is as follows: In the first aspect of this application, the present invention discloses a method for repairing converter flue gas, comprising the following steps: Cut the severely damaged parts of the flue; Take a heat-receiving pipe of the same length as the cut section and install it at the flue cut. Then weld the heat-receiving pipe to the flue. The gaps between the heated tubes are sealed.

[0006] According to one embodiment of the present invention, before cutting the severely damaged part of the flue, the severely damaged part of the flue is first identified.

[0007] According to one embodiment of the present invention, images of undamaged flues or flues with a degree of damage within a reasonable range are collected to form a qualified database. Real-time images of the flues are compared with images in the qualified database, and the parts of the real-time images that are inconsistent with the images in the qualified database are the severely damaged parts of the flues.

[0008] According to one embodiment of the present invention, images of flues with damage exceeding a reasonable range are collected to form a defect database. Real-time images of the flues are compared with images in the defect database, and the parts of the real-time images that are consistent with the images in the defect database are the severely damaged parts of the flues.

[0009] According to one embodiment of the present invention, after the flue is cut, a heating pipe is prefabricated according to the shape of the cut flue, and the shape of the heating pipe is consistent with the cross-sectional shape of the cut part of the flue along the axis.

[0010] According to one embodiment of the present invention, before installing the heated tube into the flue, a nickel-based wear-resistant layer is first deposited on the outer wall of the heated tube, the wear-resistant layer having a thickness of 2 mm to 3 mm.

[0011] According to one embodiment of the present invention, a 4-inch diameter is cut at the opening of the heated tube. 45° break.

[0012] According to one embodiment of the present invention, after the heat-receiving pipe is installed, a skylight is opened on the header of the flue to clean out debris.

[0013] According to one embodiment of the present invention, in the step of sealing the gap between the heated tubes, threaded steel with a diameter of 8 mm to 12 mm is used to seal the gap between the heated tubes.

[0014] According to one embodiment of the present invention, at least one threaded steel bar is used to seal the space between two adjacent heated pipes.

[0015] As can be seen from the above technical solution, the converter flue repair method disclosed in this application includes the following steps: First, the severely damaged part of the flue is cut. Then, a heat-receiving tube of the same length as the cut part is installed at the cut end of the flue, and the heat-receiving tube is welded to the flue. Finally, the gaps between the heat-receiving tubes are sealed.

[0016] The converter flue repair method disclosed in this application involves cutting off the severely damaged section as a whole and replacing it with a completely new section of heating tube, fundamentally eliminating the risk of continued corrosion of the old tube. This invention uses heating tubes (i.e., evaporative heating surface tubes) as replacement parts, rather than ordinary steel pipes. The heating tubes themselves are components of the flue evaporative cooling system and possess excellent high-temperature resistance. Attached Figure Description

[0017] To enable those skilled in the art to more clearly understand this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0018] Figure 1 A flowchart illustrating a converter flue repair method in one or more embodiments of this application; Detailed Implementation To enable those skilled in the art to more clearly understand this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0019] Furthermore, reference numerals and / or reference letters may be repeated in different examples in this application. Such repetition is for simplification and clarity purposes and does not in itself indicate a relationship between the various embodiments and / or settings discussed. In addition, this application provides examples of various specific processes and materials; however, those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0021] The current industry standard for online repair involves locally patching the leak and then using other pipes to seal it. However, this method has several drawbacks: First, it's a point-to-point repair, only temporarily addressing the existing leak and failing to address the overall thinning and deterioration of the pipe wall. Second, because adjacent pipe sections have undergone the same corrosion and wear process, leaks quickly reappear shortly after repair. Third, the repair frequency is high, the results are poor, and each repair requires production shutdowns, severely impacting production continuity and output.

[0022] Therefore, this invention discloses a method for repairing converter flue, which can solve the technical problems of high maintenance frequency and poor effect of existing converter flue repair methods, thereby enabling the flue to have a longer service life, significantly reducing the maintenance frequency, and ensuring safe and continuous production of the converter.

[0023] The technical solutions of this application will be described in detail below through specific embodiments and in conjunction with the accompanying drawings, which are not necessarily drawn to scale. Similar or identical reference numerals may be used to designate the same or similar parts in different figures. The use of similar or identical reference numerals in different figures does not mean that all figures including similar or identical reference numerals constitute a single or the same embodiment. The accompanying drawings illustrate the various embodiments discussed in this application in a generalized manner, by way of example and not limitation.

[0024] See Figure 1 In the first aspect of this application, a method for repairing a converter flue is disclosed, comprising the following steps: Cut the severely damaged parts of the flue.

[0025] Take a heat-receiving pipe of the same length as the cut section and install it at the flue cut. Then weld the heat-receiving pipe to the flue.

[0026] The gaps between the heated tubes are sealed.

[0027] The converter flue repair method disclosed in this embodiment involves cutting the severely damaged section as a whole and replacing it with a completely new section of heating tube, fundamentally eliminating the risk of continued corrosion of the old tube. This invention uses heating tubes (i.e., evaporative heating surface tubes) as replacement parts, rather than ordinary steel pipes. The heating tubes themselves are components of the flue evaporative cooling system and possess excellent high-temperature resistance.

[0028] In one embodiment, the severely damaged portion of the flue is identified before cutting it.

[0029] In one embodiment, images of undamaged flues or flues with damage within a reasonable range are collected to form a qualified database. Real-time images of the flues are compared with images in the qualified database, and the parts of the real-time images that are inconsistent with the images in the qualified database are the severely damaged parts of the flues.

[0030] In one embodiment, images of flues with damage levels exceeding a reasonable range are collected to form a non-conforming database. Real-time images of the flue are compared with images in the non-conforming database, and the portion of the real-time image that matches the image in the non-conforming database is the severely damaged portion of the flue.

[0031] In one embodiment, after the flue is cut, a heating pipe is prefabricated according to the shape of the cut flue, and the shape of the heating pipe is consistent with the cross-sectional shape of the cut part of the flue along the axis.

[0032] In one embodiment, a nickel-based wear-resistant layer with a thickness of 2 to 3 mm is deposited on the outer wall of the heated pipe before it is installed into the flue.

[0033] This invention involves welding a 2-3 mm thick nickel-based wear-resistant layer onto the outer wall of the heated pipe. The wear resistance of the nickel-based alloy is 3 to 5 times that of carbon steel. The nickel-based alloy has excellent high-temperature strength, corrosion resistance, and wear resistance, and can effectively resist the continuous scouring of high-temperature dusty flue gas. This significantly improves the wear resistance of the newly installed heated pipe compared to ordinary pipes, further extending the service life after repair.

[0034] In one embodiment, 4 cuts are made at the opening of the heated pipe. 45° break.

[0035] The bevel angle and size design ensures that the weld can fully penetrate during welding, resulting in good weld joint quality and avoiding the risk of secondary leakage due to welding defects.

[0036] Among them, 4 A 45° bevel indicates a bevel depth of 4 mm and a bevel angle of 45 degrees. This means that a 4 mm thick, 45° inclined bevel is cut off from the edge of the pipe opening to expose the metal.

[0037] Of course, set the break point to 4. 45° is only one implementation method in this embodiment. In other implementation methods, the thickness and angle of the bevel can be adaptively adjusted according to the shape of the flue cutting part, so as to achieve a better sealing effect after welding.

[0038] In one embodiment, after the heat-receiving pipe is installed, a skylight is opened on the header of the flue to clean out debris.

[0039] During welding, slag, spatter, and other debris can fall into the pipes. If not removed, they can clog the flue or affect heat exchange. Thoroughly cleaning away the slag, iron filings, and other debris generated during cutting and welding prevents blockages in the pipes or secondary damage during system operation, ensuring the safe and reliable operation of the repaired flue system.

[0040] In flue or boiler systems, the densely packed tubes are not independent; their lower (or upper) ends converge onto a larger pipe called a header. The header is the convergence point; opening one port allows for cleaning the interior of all the heated tubes connected to it. If each tube had an opening, the workload would be large and the system would be weakened.

[0041] In one embodiment, in the step of sealing the gap between the heated tubes, threaded steel with a diameter of 8 mm to 12 mm is used to seal the gap between the heated tubes.

[0042] The surface texture of rebar can enhance its bonding force with the sidewalls of the gap, resulting in a good sealing effect.

[0043] In one embodiment, at least one threaded steel bar is used to seal between two adjacent heated pipes.

[0044] This ensures that the gaps are fully filled, effectively preventing the problem of intensified local erosion caused by flue gas flowing through the gaps between pipes. This sealing process is simple to operate, low in cost, and highly reliable.

[0045] As one embodiment of this application, the following operations can be performed: Multiple water leaks occurred in the tail flue of a converter during operation. First, real-time images of the flue's inner wall were collected using an endoscopic device and compared region by region with a pre-established qualified database (images of undamaged or slightly damaged flues). Areas that did not match the qualified images were identified as severely damaged sections, with a length of approximately 1.2 meters.

[0046] The 1.2-meter damaged section was completely cut and removed. Based on the cross-sectional shape of the cut flue (elliptical, major axis 320mm, minor axis 210mm), a heat-receiving tube of the same shape and length, 1.2 meters long, was prefabricated. A nickel-based wear-resistant layer, 2.5mm thick, was welded onto the outer wall of the heat-receiving tube. Four × 45° cuts were made at both ends of the heat-receiving tube.

[0047] The heating pipes are installed at the flue gas incision point and welded to the flue gas wall using argon arc welding. The gaps between adjacent heating pipes are sealed with 10mm diameter threaded steel bars, with two threaded steel bars filling the space between every two adjacent heating pipes to ensure a tight seal.

[0048] After the heat pipes are installed, a 400mm×400mm skylight is opened on the flue header. After cleaning up all the welding slag, broken pipes and other debris generated during the cutting and installation process, the skylight is sealed.

[0049] After the repair, the flue operated for 18 months without any water leakage, whereas the original patching method usually required repairs again every 6 to 8 months.

[0050] In other embodiments of this application, a defective database approach can be used to locate damaged areas. A large number of flue images with damage exceeding a reasonable range are pre-collected to establish a defective database. After acquiring real-time images, they are compared with the defective database; areas that match are identified as severely damaged portions, and the cutting range is determined accordingly. Subsequent steps are the same as described above.

[0051] Through the above embodiments, this application has the following beneficial effects or advantages: This invention abandons the traditional point-patch repair method, instead performing a complete cut-and-replacement of the severely damaged section with entirely new heating pipes. The newly replaced heating pipes have complete wall thickness and good mechanical properties, enabling them to withstand the corrosion and erosion of high-temperature flue gas again, eliminating all potential water leakage hazards in this section at once, and giving the flue a longer service life. Practical application verification shows that the service life of a flue repaired using this invention is more than three times longer than that of the traditional patch repair method.

[0052] In traditional patching and repair methods, new leaks often appear in other areas shortly after repair due to varying degrees of thinning and deterioration in adjacent pipe walls, leading to frequent boiler shutdowns for maintenance. This invention, however, significantly improves repair quality and extends repair intervals by replacing the entire damaged section, drastically reducing downtime caused by maintenance and increasing converter operating rates.

[0053] This invention provides two damage area determination schemes based on image comparison databases (qualified database comparison method and unqualified database comparison method), which can quickly and accurately identify severely damaged parts of the flue, avoiding the subjective errors and omissions caused by traditional judgment based on human experience, ensuring that the damaged section is completely and accurately removed, and improving the accuracy and efficiency of maintenance.

[0054] This invention prefabricates the heating pipe according to the shape of the flue to be cut, so that the shape of the heating pipe is consistent with the cross-sectional shape of the flue cut section along the axis, ensuring good matching between the old and new pipe sections, reducing the difficulty of on-site installation, and improving welding quality and repair efficiency.

[0055] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention have been clearly and completely described above with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0056] Therefore, the above detailed description of the embodiments of the invention disclosed in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0057] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0058] In the description of this invention, it should be understood that the terms indicating orientation or positional relationship are based on the orientation or positional relationship shown in the drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0059] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0060] In this invention, unless otherwise expressly specified and limited, "above or below" a first feature may include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on" the first feature includes the first feature 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," and "under" the first feature includes the first feature 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.

[0061] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0062] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for repairing converter flue gas, characterized in that, Includes the following steps: Cut the severely damaged parts of the flue; Take a heat-receiving pipe of the same length as the cut section and install it at the flue cut. Then weld the heat-receiving pipe to the flue. The gaps between the heated tubes are sealed.

2. The converter flue repair method according to claim 1, characterized in that, Before cutting the severely damaged part of the flue, first identify the severely damaged part of the flue.

3. The converter flue repair method according to claim 2, characterized in that, Collect images of undamaged or reasonably damaged flues to form a qualified database. Compare real-time images of the flue with the images in the qualified database. The parts of the real-time images that are inconsistent with the images in the qualified database are the severely damaged parts of the flue.

4. The converter flue repair method according to claim 2, characterized in that, Images of flues with damage levels exceeding a reasonable range are collected to form a non-conforming database. Real-time images of the flues are compared with images in the non-conforming database, and the parts of the real-time images that match the images in the non-conforming database are the severely damaged parts of the flues.

5. The converter flue repair method according to any one of claims 1 to 4, characterized in that, After the flue is cut, a heating pipe is prefabricated according to the shape of the cut flue. The shape of the heating pipe is consistent with the cross-sectional shape of the cut part of the flue along the axis.

6. The method for repairing converter flue gas ducts according to any one of claims 1 to 4, characterized in that, Before installing the heated pipe into the flue, a nickel-based wear-resistant layer is deposited on the outer wall of the heated pipe, with a thickness of 2 to 3 millimeters.

7. The converter flue repair method according to any one of claims 1 to 4, characterized in that, Cut a 4*45° slit at the opening of the heated pipe.

8. The method for repairing converter flue gas ducts according to any one of claims 1 to 4, characterized in that, After the heating pipes are installed, a skylight is opened on the header of the flue, and debris is cleaned out through the skylight.

9. The method for repairing converter flue gas ducts according to any one of claims 1 to 4, characterized in that, In the step of sealing the gaps between the heated pipes, threaded steel with a diameter of 8 mm to 12 mm is used to seal the gaps between the heated pipes.

10. The converter flue repair method according to claim 9, characterized in that, At least one threaded steel bar is used to seal the space between two adjacent heated pipes.

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