Tuyere for metallurgical furnace

Abstract

A tuyere includes a tapered hollow tuyere body having an inner surface and an outer surface, the tuyere extending along a first axis from an inlet end to an opposite outlet end, the tuyere body having a tuyere tip at the outlet end and a tapered junction surface at the inlet end. The tapered connection surface is configured to engage a tapered seat of a tuyere cooler or tuyere mount. Advantageously, the tuyere also includes a corrugated portion on an outer surface of the tuyere. The corrugated portion includes at least one recess having an open curved profile and a surface surrounding the at least one recess. The corrugated portion is arranged and configured for supporting charge and forming a support for charge during operation of the metallurgical furnace.

Description

Technical Field

[0001] The present invention generally relates to the field of metallurgical furnaces, and more particularly to a tuyere with an extended service life for blowing gas into a metallurgical furnace. Background Art

[0002] Tuyeres are an important part of metallurgical furnaces, such as blast furnaces, because they blow gases into the furnace away from the walls, thus preventing damage to the walls. Modern blast furnaces usually include more than two dozen such tuyeres around the furnace wall. The tuyeres are usually inserted into a tuyere cooler that includes a circuit for a cooling liquid. The tuyere and tuyere cooler are tightly pressed into an opening in the furnace wall, called a tuyere cooler support. In addition, the tuyere itself usually includes at least one circuit for a cooling liquid.

[0003] Due to the very harsh conditions inside the tuyere center, tuyeres and tuyere coolers usually break down and need to be replaced after a while. Tuyere components often burn out or wear out due to abrasion, hampering the proper operation of the furnace. Their damage can also lead to gas or water leaking out of the furnace, posing a high risk to the health and safety of workers around the furnace. Currently, tuyeres with a cooling circuit of single-chamber design, which wear out due to abrasion or melting and start leaking into the furnace, are therefore bypassed, causing them to fail completely. This means that the metallurgical furnace is shut down unplanned to replace the defective tuyere. The service life of a tuyere varies from a few days to several months, depending on the tuyere design and the productivity of the furnace, which requires regular maintenance operations at relatively short intervals. Unplanned shutdowns of metallurgical furnaces for the purpose of replacing defective tuyeres last at least 4 to 8 hours. The production loss caused by such a shutdown economically exceeds the cost of the entire set of tuyeres installed in the furnace. Therefore, improvements in tuyere components of metallurgical furnaces, in particular tuyere, with improved heat and impact resistance to liquid metal droplets, raceway material or falling material are important in the operation of the blast furnace itself.

[0004] Solutions have been developed to improve the design of tuyere and increase their wear resistance. Most of these improvements involve applying a wear-resistant coating to the outer surface or providing the tuyere with more cooling ducts.

[0005] Among the solutions known in the prior art, CN 207793315 U discloses coating the tuyere tip and the outer surface of the tuyere with a wear-resistant alloy, which includes both a wear-resistant transition layer for enhancing adhesion to the tuyere material and a wear-resistant working layer located on the wear-resistant transition layer to provide increased wear resistance. Although the use of such a wear-resistant alloy does enhance the wear resistance of the tuyere, it does not protect the tuyere from damage caused by liquid metal droplets, raceway material or falling material. Therefore, tuyere failure is only delayed, but not completely avoided.

[0006] Another solution is disclosed in EP 2 669 388 A1. The tuyere comprises two nose tubes and three different cooling tubes, which are stacked on top of each other to form a stack between the inner and outer surfaces of the tuyere. According to EP 2 669 388 A1, wear on the outer surface of the tuyere causes leakage of the outermost cooling tube, which only needs to be bypassed, rather than the entire tuyere, because the remaining two cooling tubes can still provide sufficient cooling. However, this tuyere is time-consuming and expensive to manufacture, and does not solve the problem of excessive wear on the outer surface of the tuyere. Summary of the invention

[0007] It is therefore an object of the present invention to provide an improved design of a tuyere for a metallurgical furnace having a prolonged service life without the aforementioned disadvantages.

[0008] This object is achieved by a tuyere according to claim 1 .

[0009] Purpose of the Invention

[0010] The present invention overcomes the above-mentioned drawbacks and disadvantages by providing a tuyere for a metallurgical furnace, the tuyere comprising a conical hollow tuyere body having an inner surface and an outer surface. The tuyere extends along a first axis from an inlet end to an opposite outlet end, the tuyere body having a tuyere tip at the outlet end and a conical connecting surface at the inlet end. The conical connecting surface is configured to engage a conical seat of a tuyere cooler or a tuyere support.

[0011] The tuyere further comprises a corrugated portion on the outer surface of the tuyere, the corrugated portion comprising at least one recess, the at least one recess having an open curved profile and a surface surrounding the at least one recess, and the corrugated portion is arranged and constructed to support the charge during operation of the metallurgical furnace and form a support for the charge, in other words, the falling charge is retained in the recess and will accumulate in the recess and on the surface of the corrugated portion. Thus, the corrugated portion promotes the formation of a support for the charge and fixes the support in place. Such a support can not only protect the tuyere from wear caused by the impact of liquid metal droplets and raceway material, but also prevent the falling of the charge.

[0012] Furthermore, the thickness of the tuyere from the inner surface to the outer surface includes a thicker portion, and the at least one recess of the corrugated portion is arranged in the thicker portion. In other words, the tuyere has an eccentric shape, which constitutes an extra thickness of the tuyere forming material on a portion of the outer surface of the tuyere. The at least one recess of the corrugated portion is formed in this extra thickness so as not to weaken the tuyere locally. This extra thickness provides the stability and support required to form the corrugated portion.

[0013] The corrugated portion is preferably arranged on the upper outer surface of the tuyere, ie on a portion of the outer surface close to the falling charge and on which the falling charge may accumulate.

[0014] In the context of this application, "corrugation" refers to a series of preferably parallel ridges and valleys. In other words, in this context, a corrugated portion is a surface that looks like a series of waves when viewed from one end of the tuyere. In the context of this application, the term "recess" refers to an indented space in a surface and is a synonym for a groove, a groove or a corrugation.

[0015] The main advantage of the tuyere is that it helps, promotes and increases the formation of the support on it, thus forming a protective layer. This charge protection layer acts like a thermal insulation layer and reduces the heat load on the tuyere, resulting in a reduction in heat load.

[0016] Furthermore, during the operation of the metallurgical furnace, the falling material, the raceway material and the liquid metal droplets are advantageously gathered into the support and reinforce the support. Heat and / or abrasion may damage the support, but not the tuyere. In other words, the support can be continuously consumed and regenerated during the operation of the metallurgical furnace, so that the outer surface of the tuyere is not exposed to the harsh conditions of the furnace, but is protected from the impact by the support. Heat and / or abrasion damage mainly occurs on the support of the charge, so the damage to the tuyere is greatly limited, which greatly prolongs the service life of the tuyere.

[0017] Advantageously, a tuyere comprising a corrugated portion will have sufficient resistance to ensure continuous operation of the tuyere, even if there is some loss of tuyere forming material due to the support of the charge under thermal radiation, which support is constantly formed and renewed.

[0018] In other words, such a tuyere enables and promotes the formation, renewal and regeneration of the charge support on the tuyere top, protected from excessive thermal loads and abrasive / erosive wear, without requiring changes in the furnace process parameters (such as gas blowing and charge composition).

[0019] The charge is retained and forms a self-protecting accumulation layer, such as a charge support, corresponding to the so-called stone box effect.

[0020] Another advantage of this tuyere is that the at least one recess of the corrugated portion has an open curved profile. The recess can have any profile, such as circular, square or triangular, as long as the profile widens when viewed from the inner surface of the tuyere towards the outer surface.

[0021] Such an open curved profile is easier to manufacture than a closed curved profile, such as a dovetail design. In fact, unlike a closed curved profile which requires machining or milling of the tuyere to remove material corresponding to the recess, the recess presenting an open curved profile can be cast directly during the production of the tuyere and does not require any subsequent manufacturing steps.

[0022] In some embodiments, the corrugated portion may be made of an alloy of nickel, chromium, zirconium, titanium, and / or tungsten, which further protects the corrugated portion from falling drops and abrasion.

[0023] It is also within the scope of the present disclosure that the recess is coated with a layer of protective material, such as a refractive material. However, a preferred embodiment is that the recess is not filled to the outer edge with protective material to accommodate and hold the falling charge to form a support during operation of the blast furnace.

[0024] Another advantage is that modifications to the tuyere design involving / including forming corrugated portions on the outer surface are directly embedded in the manufacturing process of the tuyere, i.e. they are made simultaneously with the tuyere.

[0025] The costs associated with these modifications are practically non-existent, or at least greatly reduced, since there is no need to manufacture additional protective components, such as an additional protective layer on the outer surface of a conventional tuyere, or to arrange, provide and fix additional protrusions or ribs on the outer surface of the tuyere. In other words, the at least one recess of the corrugated portion is formed directly in the outer surface of the tuyere, and the surface surrounding the at least one recess is the outer surface of the tuyere.

[0026] Another advantage of the tuyere is that it does not require any design changes to the entire assembly. These tuyeres can be easily used in new metallurgical furnaces or can be used to retrofit existing furnaces during maintenance operations, such as replacing damaged tuyere.

[0027] In some preferred embodiments, the corrugated portion comprises a plurality of recesses, each of the plurality of recesses having an open curved profile. Preferably, the corrugated portion comprises between three and eleven recesses, more preferably, the corrugated portion comprises between five and nine recesses.

[0028] In some embodiments, the surface of the corrugated portion surrounds the plurality of recesses. It may extend between each of the plurality of recesses.

[0029] Advantageously, the corrugated surface including the plurality of recesses easily retains any fallen charge material, thereby improving the formation of the support and the resulting stone box effect.

[0030] In the same or alternative embodiments, each recess of the corrugated portion may be discontinuous.The resulting rock box effect is maximized due to the accumulation of charge in the recesses and on top of the tuyere.

[0031] In some preferred embodiments, the recesses are parallel to each other and extend substantially along the second axis.

[0032] Advantageously, the second axis is not coaxial with the first axis. The fact that the second axis is not coaxial with the first axis means that the recess is arranged and oriented to form an angle with respect to the axis of the tuyere. The greater the angle, the better the charge is retained in the recess, thereby improving the formation of a support protecting the upper outer surface of the tuyere. If the first and second axes were coaxial, the charge would not be retained by the recess, since the recess would be oriented along the falling material flow.

[0033] Preferably, the second axis is perpendicular to the first axis. If the recess is arranged perpendicular to the charge flow direction, the retention of falling charge, the formation of a support and the resulting stone box effect are thereby maximized. This particular orientation of the recess enhances the protection of the tuyere from excessive thermal loads and abrasive wear, thereby extending its service life. However, the orientation may be V-shaped.

[0034] The recesses may have any shape, but preferably all recesses have a similar shape. In some embodiments, the recesses may have a linear shape, i.e. the recesses are formed as straight lines presenting an open curved profile. Alternatively, the recesses may have a wavy shape or an angular shape.

[0035] Advantageously, the tuyere can be made of any metal material or alloy of any metal material to ensure its heat resistance and wear resistance. However, the tuyere is preferably made of copper, copper alloy, steel or steel alloy.

[0036] In some embodiments, the surface of each recess forming the corrugated portion is covered with a layer of a metal material or an alloy of metal materials to further enhance its heat resistance and wear resistance. This additional layer provides additional protection against wear caused by falling charge materials and droplets of liquid metal (mainly iron). Preferably, the surface of each recess is covered with a layer of copper, copper alloy, nickel, nickel alloy, steel or steel alloy.

[0037] According to the same or alternative embodiments, the surface of the corrugated portion and / or the tip of the tuyere is covered with a layer of hard facing material, such as a Cr / Fe alloy and / or a Cr / Ni alloy, such as Inconel 625. Hard facing refers to a thick coating of hard, wear-resistant material deposited on the surface of a worn or new part that will wear during use. It is usually welded to a substrate, generally in the form of a special electrode for arc welding, or a welding rod for oxyacetylene welding and tungsten inert gas arc welding. The surfaces covered with hard facing materials are the surfaces most susceptible to heat or wear. Covering them with hard facing materials can improve their heat resistance and wear resistance.

[0038] The tuyere can be of any type. In particular, the tuyere can include a single cavity, a double cavity and / or a spiral cavity. In a preferred embodiment, the tuyere also includes a cast nose tube and a double cavity, wherein the double cavity is preferably composed of an inner cavity and a spiral serpentine. Advantageously, due to the inner cavity and the serpentine, the nose tube will not leak even if the tip of the tuyere is worn. If the first cavity (serpentine or inner cavity) is not sufficient to ensure adequate cooling of the tuyere and / or should suffer damage, the second cavity (inner cavity or serpentine) of the double cavity design can provide backup cooling.

[0039] Preferably, the tube of the nose tube is made of a metal material or an alloy of a metal material. More preferably, the tube is made of copper, copper alloy, nickel, nickel alloy, steel or steel alloy. Such materials have a high melting point, thereby providing the tube with protection against wear and iron droplets once the outer surface of the tuyere is worn.

[0040] In some embodiments, the tuyere further comprises an injection channel arranged and configured for injecting charge material directly above the tuyere during operation of the metallurgical furnace. Advantageously, such an injection channel promotes the formation of a cradle in and above the recess of the corrugated portion and thereby improves thermal and wear protection of the tuyere.

[0041] According to the same or other embodiments, the tuyere further comprises a straight passage arranged and configured for use with an electronic thickness measurement device during operation of the metallurgical furnace.

[0042] Another object of the present invention is to provide a method for manufacturing a tuyere according to the present invention. In some embodiments, the tuyere is manufactured by machining, casting, welding, forging or any combination of these manufacturing methods. Preferably, the concave portion of the corrugated portion is manufactured by casting.

[0043] Yet another aspect of the present invention provides a metallurgical furnace comprising a tuyere arranged for supplying hot gas in the metallurgical furnace, wherein the tuyere is a tuyere according to the present invention.

[0044] The method according to the invention and the metallurgical furnace according to the invention retain all the advantages of the tuyere according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Further details and advantages of the present invention will be apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings, in which:

[0046] Figure 1 It is a schematic diagram of the overall arrangement of the tuyere;

[0047] Figure 2 is a schematic diagram of the tuyere of the present invention;

[0048] Figure 3 yes Figure 2 A schematic cross-sectional perspective view of the air outlet along the AA axis, and

[0049] Figure 4 yes Figure 2 Schematic cross-sectional view of the air outlet along the AA axis. DETAILED DESCRIPTION

[0050] In a metallurgical furnace, a plurality of tuyere 10 is usually located inside the furnace wall 12 to supply hot gases into the furnace. Figure 1 As shown, the tuyere 10 is arranged in a furnace wall 12, usually in a tuyere cooler 14, which in turn is arranged in a tuyere support 16. The tuyere 10, the tuyere cooler 14 and the tuyere support 16 are firmly wedged into each other via conical surfaces that narrow toward the furnace interior.

[0051] The tuyere 10 has a conical hollow tuyere body 18 having an inner surface 20 and an outer surface 22. The tuyere body 18 extends along a first axis AA from an outlet end 24 opening toward the furnace interior to an inlet end 26 receiving the tip of a blow tube 28.

[0052] The outer surface of the tuyere includes Figure 2 The corrugated portion 34 is shown. The corrugated portion 34 is formed on an upper portion 30 of the outer surface 22 of the tuyere 10. In this context, the adjectives "upper" and "lower" must be considered to refer to the relative orientation of the tuyere in the operating position, i.e. to the orientation of the tuyere installed in a metallurgical furnace. Thus, the upper portion 30 of the outer surface 22 is the portion of the outer surface facing the furnace top, and the lower portion 32 of the outer surface 22 is the portion of the outer surface facing the furnace bottom.

[0053] like Figure 2 1, the corrugated portion 34 includes seven recesses 36, which are arranged and configured to support the charge during operation of the metallurgical furnace and form a support for the charge on the top of the tuyere 10. The corrugated portion 34 must include at least one recess 36 to hold and support the falling charge. However, the corrugated portion 34 can include any suitable number of recesses 36 to achieve the desired effect, depending on the characteristics of the tuyere (such as its length) and the operating conditions of the metallurgical furnace, so Figure 2 The embodiments are merely illustrative, non-limiting embodiments.

[0054] The recesses 36 are preferably formed directly in the outer surface 22 of the tuyere 10, ie, each recess 36 forms a groove or an indented space in the outer surface 22 of the tuyere 10. Figure 2-4 It can be seen from the figure that the surface surrounding the recess is the outer surface of the tuyere.

[0055] The recesses 36 are evenly distributed along the length of the corrugated portion 34. In alternative embodiments, the space between two adjacent recesses may vary from one group of two recesses to an adjacent group (not shown). For example, the space between two adjacent recesses may be larger near the inlet end of the tuyere. Alternatively, the space may be larger near the outlet end of the tuyere.

[0056] The recess 36 is not formed as one continuous recess, but is formed as parallel recesses 36 that are discontinuous with each other. Figures 2 to 4 As shown, the recess 36 has a linear shape and a circular open curved profile 38, which promotes the retention and support of the falling charge to form a support for the charge on the upper portion 30 of the outer surface 22 of the tuyere 10. The recess 36 can have any suitable shape, such as a wavy or angular shape, and any type of open curved profile, such as a square or a triangle (not shown).

[0057] The parallel recesses 36 extend substantially along the second axis BB. The second axis BB is perpendicular to the first axis AA of the conical hollow tuyere body 18. In other words, the recesses 36 are perpendicular to the axis of the tuyere body 18. This orientation of the recesses maximizes the retention of falling charge material, the formation of a support and the resulting stone box effect.

[0058] Even if not explicitly shown, every alternative embodiment in which the second axis BB is neither perpendicular nor coaxial with the axis AA of the tuyere body is part of the present disclosure and still within the scope of the present invention.

[0059] according to Figure 3 and Figure 4 In the embodiment shown in the cross-sectional view of FIG. 1 , the tuyere 10 includes a cast nose tube 40, a spiral serpentine tube 42, and an inner cavity 44. Each of the spiral serpentine tube 42 and the inner cavity 44 is formed between the inner surface 20 and the outer surface 22 of the tuyere body 18. The spiral serpentine tube 42 is closer to the outer surface 22 than the inner cavity 44, and the inner cavity 44 is closer to the inner surface 20 than the spiral serpentine tube 42. The technician can know the appropriate size for various tubes according to the design of the tuyere. However, the appropriate tube can be selected from a tube with an inner diameter of 1 / 4 Pipes between 2" and 1".

[0060] according to Figure 4In the embodiment shown, the tuyere body 18 is made of copper, and the surface of each recess 36 is coated with a layer 46 made of copper, a copper alloy, nickel, a nickel alloy, steel or a steel alloy. The upper portion 30 of the outer surface 22 of the tuyere 10, including the corrugated portion 34 and thus including the surface of the corrugated portion 34 surrounding the recess 36 and extending between the recesses 36, is covered with a hard facing material 48. The tip of the tuyere is covered with the same hard facing material 48. In some embodiments, two different hard facing materials can be used to cover the tip of the tuyere and the upper outer surface of the surface. The tubes of the nose tube 40 and the spiral serpentine tube 42 are made of copper, a copper alloy, nickel, a nickel alloy, steel or a steel alloy.

[0061] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. The invention is not limited to the disclosed embodiments.

[0062] Reference numerals list

[0063] 10. Air outlet

[0064] 12 Furnace wall

[0065] 14 Air outlet cooler

[0066] 16 Air outlet support

[0067] 18 Tuyere body

[0068] 20 Inner surface

[0069] 22 External surface

[0070] 24 Exit

[0071] 26 Entrance

[0072] 28 Blowpipe

[0073] 30 Upper part

[0074] 32 Lower part

[0075] 34 Corrugated part

[0076] 36 recess

[0077] 38 Open curved profile

[0078] 40 Casting nose tube

[0079] 42 spiral serpentine tube

[0080] 44 Lumen

[0081] 46 concave coating

[0082] 48 Hard facing materials

[0083] AA Axis of the air outlet

[0084] BB Axis of the concave part

Claims

1. A tuyere for a metallurgical furnace, the tuyere comprising a conical hollow tuyere body having an inner surface and an outer surface, the tuyere extending along a first axis from an inlet end to an opposite outlet end, the tuyere body having a tuyere tip at the outlet end and a conical connecting surface at the inlet end, the conical connecting surface being configured to engage a conical seat of a tuyere cooler or a tuyere support, It is characterized in that The tuyere further comprises a corrugated portion on an outer surface of the tuyere, the corrugated portion comprising at least one recess having an open curved profile and a surface surrounding the at least one recess, and the corrugated portion is arranged and configured to support a charge during operation of the metallurgical furnace and form a support for the charge, wherein the thickness of the tuyere from the inner surface to the outer surface includes a thicker portion, and wherein the at least one recess of the corrugated portion is disposed in the thicker portion.

2. The tuyere according to claim 1, wherein: The corrugated portion comprises a plurality of recesses, each of the plurality of recesses having an open curved profile, preferably the corrugated portion comprises between three and eleven recesses, more preferably the corrugated portion comprises between five and nine recesses, and wherein the surface of the corrugated portion surrounds the plurality of recesses and extends between each of the plurality of recesses.

3. The tuyere according to claim 1 or 2, wherein: Each concave portion of the corrugated portion is discontinuous.

4. The tuyere according to any one of claims 1 to 3, wherein the recesses are parallel to each other and extend substantially along a second axis, and wherein the second axis is not coaxial with the first axis.

5. The tuyere according to claim 4, characterized in that: The second axis is perpendicular to the first axis.

6. The tuyere according to any one of claims 1 to 5, wherein: The recess has a linear shape.

7. The tuyere according to any one of claims 1 to 5, characterized in that: The concave portion is wavy or angular.

8. The tuyere according to any one of claims 1 to 7, characterized in that: The tuyere is made of a metal material or an alloy of a metal material, and preferably the tuyere is made of copper, a copper alloy, steel or a steel alloy.

9. The tuyere according to any one of claims 1 to 8, characterized in that: The surface of each recess forming the corrugated portion is covered with a layer of metal material or an alloy of metal material, preferably, the surface of each recess is covered with a layer of copper, copper alloy, nickel, nickel alloy, steel or steel alloy.

10. The tuyere according to any one of claims 1 to 9, characterized in that: The surface of the corrugated portion and the tip of the tuyere are covered with a layer of hard facing material.

11. The tuyere according to any one of claims 1 to 10, characterized in that: The tuyere includes a single cavity, a double cavity and / or a spiral cavity.

12. The tuyere according to any one of claims 1 to 11, characterized in that: The tuyere also includes a cast nose tube.

13. The tuyere according to claim 12, characterized in that: The tube of the nasal tube is made of a metal material or an alloy of a metal material, and preferably the tube is made of copper, a copper alloy, nickel, a nickel alloy, steel or a steel alloy.

14. The tuyere according to any one of claims 1 to 13, further comprising an injection channel arranged and configured for injecting charge material directly above the tuyere during operation of the metallurgical furnace.

15. The tuyere according to any one of claims 1 to 14, wherein the tuyere further comprises a straight passage arranged and configured for use with an electronic thickness measurement device during operation of the metallurgical furnace.

16. A method of manufacturing a tuyere according to any one of claims 1 to 15.

17. The method according to claim 16, wherein: The tuyere is manufactured by machining, casting, welding, forging or any combination thereof.

18. The method according to claim 16 or 17, wherein: The concave portion of the corrugated portion is produced by casting.

19. A metallurgical furnace comprising a tuyere configured to supply hot gas to the interior of the metallurgical furnace, wherein: The tuyere is the tuyere according to any one of claims 1 to 15.

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