Single-oxygen-channel double-flow secondary combustion oxygen lance nozzle

Abstract

The invention relates to a single oxygen channel double flow secondary combustion oxygen lance nozzle which comprises a forging nozzle crown, an outer pipe, a sliding connecting pipe, a water baffle, an inner pipe and a secondary combustion spray pipe, the inner pipe, the sliding connecting pipe and the outer pipe are sequentially arranged from outside to inside, the outer diameter of the forging nozzle crown is connected with the outer pipe in a welded mode, and the water baffle is connected with an oxygen column of the forging nozzle crown in a welded mode. The outer diameter of the water baffle is in threaded connection with the sliding connecting pipe, the oxygen column end of the forged sprayer head crown is welded to the oxygen column end of the head of the inner pipe, the secondary combustion spraying pipe is obliquely connected to the side face of the outer pipe, the side face of the sliding connecting pipe and the side face of the inner pipe in a penetrating mode, and one end of the secondary combustion spraying pipe is welded and fixed to the outer pipe. And the other end of the secondary combustion spray pipe is welded and fixed with the inner pipe. On the basis of a traditional oxygen lance, the nozzle strength is improved, the service life of the nozzle is prolonged, meanwhile, the machining difficulty is lowered, and the yield is increased.

Description

Technical Field

[0001] This invention relates to the field of oxygen lance nozzle technology in converter steelmaking, and more particularly to a single-oxygen-channel, dual-flow, secondary combustion oxygen lance nozzle. Background Technology

[0002] The secondary combustion oxygen lance has a significant impact on the entire smelting process. With conventional oxygen lances, the initial slag formation time is approximately 4-6 minutes, and the basicity increases slowly, making "re-drying" a common occurrence in the middle stages of smelting. Using a secondary combustion oxygen lance reduces the initial slag formation time to only 3-5 minutes and eliminates the "re-drying" phenomenon in the middle stages. Due to the rapid slag formation, a relatively constant lance position can be maintained. While keeping the slag basicity essentially constant, the slag volume can be reduced by approximately 1 / 6. The split-flow oxygen lance achieves technical and economic benefits such as shortening smelting time, increasing the scrap ratio, and reducing steel scrap and solvent consumption.

[0003] The main component of converter gas is CO. The secondary combustion rate of CO is increased by about 8%, resulting in a secondary combustion thermal efficiency as high as 81.4%. Due to the increased heat of CO combustion, the scrap steel ratio increases by 2.16~3.66%. However, the secondary combustion blowing process leads to a decrease in gas quality. To ensure the quality of the gas used in production, the lance position is appropriately lowered, allowing most of the auxiliary oxygen to participate in the decarburization reaction in the molten pool, thus controlling the amount of secondary CO combustion. Furthermore, gas recovery occurs 3 minutes after oxygen blowing and before the first carbon removal, during which time CO production is relatively high.

[0004] The secondary combustion oxygen lance nozzle technology adds an auxiliary oxygen flow orifice to the traditional oxygen lance, with the main and auxiliary orifices coordinating oxygen supply to further oxidize CO in the furnace gas into CO2, releasing a large amount of heat energy and transferring it to the molten pool. This design not only alleviates the problem of insufficient heat in the molten pool but also achieves the goals of increasing the proportion of scrap steel and reducing iron consumption, reducing lance sticking, extending the service life of the oxygen lance, shortening the blowing time, and improving the converter steelmaking efficiency. By enhancing the oxygen supply intensity, the thermodynamic and kinetic conditions of the molten pool reaction are optimized, accelerating the slagging process, resulting in faster slagging and earlier slagging, with slagging appearing approximately 2 minutes earlier. The improved thermodynamic conditions lead to a rapid increase in slag basicity, resulting in good removal of S and P. Due to the good slagging, the sulfur distribution ratio is high, indicating good desulfurization. The increased basicity also facilitates dephosphorization, significantly improving desulfurization and dephosphorization efficiency. There is less metal splashing, and the consumption of steel scrap and lime is reduced, resulting in a low ∑(FeO) content in the final slag.

[0005] The most commonly used secondary combustion oxygen lance in converter steelmaking is the single-pass secondary combustion oxygen lance. During the blowing process in the converter, the oxygen injected by the lance reacts violently with the carbon in the molten iron. The carbon is oxidized, producing CO2 and CO. At low temperatures, the carbon is completely burned, with most of the product being CO2 and only a small portion being CO. However, at high temperatures, the carbon is not completely burned, so most of the product is CO, with only a small portion being CO2. Inside the converter, oxygen reacts violently with elements such as C, Si, Mn, P, S, and Fe in the molten iron, releasing a large amount of heat. The temperature in the reaction zone reaches over 2500℃, and the furnace gas temperature is also over 2000℃. Therefore, in the converter, the carbon-oxygen reaction produces approximately 75% CO and approximately 25% CO2.

[0006] The secondary nozzle has a larger opening angle, which allows it to spray a more dispersed oxygen stream to participate in the secondary combustion of CO: CO + 1 / 2O2 = CO2 + Q, where Q is the chemical heat generated by CO combustion. This heat is generated in the steel-slag emulsion of the converter's foamy slag, where absorption is excellent and thermal efficiency is very high. The carbon monoxide produced by the reaction in the molten metal pool mixes and burns with the oxygen sprayed from the secondary nozzle on the surface of the molten pool, increasing the scrap steel ratio. This solves the problem of insufficient heat in the molten pool, promotes earlier slagging of the molten pool, reduces lance sticking, extends the service life of the oxygen lance, shortens the blowing time, and improves the converter steelmaking efficiency.

[0007] However, due to the special nature of the secondary combustion oxygen lance nozzle sub-flow orifice structure currently being produced, only cast nozzles can be used for processing, and the strength of cast nozzles is limited; moreover, the precision requirements for processing the nozzle sub-flow orifice are extremely high. Therefore, processing deviations often occur between the inclination angle and diameter of the sub-flow orifice, resulting in a decrease in the yield of nozzles.

[0008] The current state of existing technology regarding secondary combustion oxygen lance nozzles is as follows:

[0009] Patent document CN220555704U describes a "single-channel, two-stage secondary combustion oxygen lance," characterized by transferring the auxiliary oxygen orifice from the nozzle of the single-channel secondary combustion oxygen lance to the oxygen lance itself. The auxiliary oxygen orifice is positioned 2.5 to 3.5 meters higher than the nozzle, which improves the lifespan of the secondary combustion orifice and enhances cooling, thus extending the nozzle's lifespan. The higher position of the auxiliary oxygen orifice allows for a longer reaction time, which is beneficial for secondary combustion with coal gas. However, this technology requires replacing the existing oxygen lance body in the steel plant, significantly increasing replacement costs, making implementation difficult, and resulting in poor feasibility.

[0010] Patent document CN106282481A describes "a structural design of a converter secondary combustion oxygen lance nozzle." This invention allows the oxygen lance to better adapt to the requirements of current converter high-cold charge ratio smelting and normal blowing gas recovery and slag splashing furnace protection. Its key feature is that the design of the secondary orifice outlet direction is not constrained by the secondary orifice inlet direction; it can be downward, horizontal, or upward. This increases the secondary combustion area of ​​the secondary orifice and improves the application effect of secondary combustion. However, due to the complex nozzle structure, it is difficult to implement in actual production.

[0011] Patent document CN114196798A describes "a single-channel secondary combustion oxygen lance and its usage method." This single-channel secondary combustion oxygen lance includes a lance body and a nozzle end face. The lance body is tubular and includes a first section, a second section, and a third section arranged sequentially along the axial direction. The diameter of the first section is larger than the diameter of the third section. The second section is conical. The large end of the first section is connected to the second section, and the small end of the second section is connected to one end of the third section. The nozzle end face is located at the other end of the third section. The lance body has an oxygen inlet hole, a main oxygen flow hole, and a secondary oxygen flow hole. The oxygen inlet hole is arranged along the axial direction of the lance body and communicates with the nozzle end face through the main oxygen flow hole. The oxygen inlet hole communicates with the side wall of the second section through the secondary oxygen flow hole, and its axis is perpendicular to the side wall of the second section. The oxygen flow rate of the secondary oxygen flow hole accounts for 15% to 20% of the total oxygen supply flow rate of the inlet hole. This can improve the overall service life of the secondary combustion oxygen lance. The thickness of the corner where the auxiliary oxygen flow hole connects to the side wall of the gun body is relatively thin. During the combustion process of the oxygen flow in the auxiliary oxygen flow hole, the corner where the auxiliary oxygen flow hole connects to the side wall of the gun body is scoured by the oxygen flow for a long time. In addition, the secondary combustion intensity at the outlet is high, which can easily lead to problems such as wear, slag adhesion and ablation. Summary of the Invention

[0012] To address the above problems, this invention designs a novel single-oxygen-channel dual-flow secondary combustion oxygen lance nozzle, which improves the nozzle strength and extends its service life compared to traditional oxygen lances, while reducing processing difficulty and increasing yield.

[0013] To achieve the above objectives, the present invention employs the following technical solution:

[0014] A single-channel dual-flow secondary combustion oxygen lance nozzle includes a forged nozzle crown, an outer tube, a sliding connector, a baffle plate, an inner tube, and a secondary combustion nozzle. From the outside outwards, the inner tube, sliding connector, and outer tube are arranged in sequence. The outer diameter of the forged nozzle crown is welded to the outer tube. The baffle plate is welded to the oxygen column of the forged nozzle crown. The outer diameter of the baffle plate is threaded to the sliding connector. The end of the oxygen column of the forged nozzle crown is welded to the end of the oxygen column at the head of the inner tube. The secondary combustion nozzle obliquely passes through the sides of the outer tube, sliding connector, and inner tube, with one end of the secondary combustion nozzle welded and fixed to the outer tube, and the other end welded and fixed to the inner tube.

[0015] Furthermore, the outer tube is welded to the outer connecting pipe by an external copper pipe, the end of the external copper pipe is connected to the forged nozzle crown, and the side wall of the external copper pipe is connected to the secondary combustion nozzle. The inner tube is welded to the inner tube head, transition section and sealing connecting pipe in sequence, and the inner tube head is welded to the secondary combustion nozzle.

[0016] Furthermore, the sliding pipe is welded together by sliding pipe one and sliding pipe two, and the other end of sliding pipe one is connected to a baffle plate by a thread.

[0017] Furthermore, the forged nozzle crown, water baffle, and inner tube head are all forged.

[0018] Furthermore, the number of secondary combustion nozzles is twice the number of oxygen columns.

[0019] Furthermore, the angle between the secondary combustion nozzle and the axis is 30° to 40°.

[0020] Compared with existing technologies, the beneficial effects of this invention are:

[0021] This invention transforms the secondary combustion nozzle forming process from casting to forging for the first time, significantly improving product performance and nozzle strength. It replaces the original one-piece thin-walled secondary combustion nozzle with an independent embedded secondary combustion auxiliary orifice nozzle design, avoiding the risk of easy penetration during drilling of thin-walled nozzles, reducing the requirements for machining accuracy, eliminating losses caused by drilling deviations, and increasing the measured yield from 60% to over 98%.

[0022] This invention overcomes the manufacturing difficulties while ensuring that the nozzle parameters remain unchanged during use, thereby improving nozzle strength, reducing manufacturing difficulty, and increasing manufacturing efficiency and yield. Attached Figure Description

[0023] Figure 1 This is a schematic front view cross-section of the oxygen lance nozzle structure.

[0024] Figure 2 This is a schematic diagram of the right-side structure of the oxygen lance nozzle.

[0025] Figure 3 This is a schematic diagram of a secondary combustion auxiliary nozzle.

[0026] Figure 1 In the middle section: 1. Forged nozzle crown; 2. External copper pipe; 3. Secondary combustion nozzle; 4. External pipe; 5. Sliding pipe one; 6. Sliding pipe two; 7. Sealing pipe; 8. Sealing ring; 9. Water baffle; 10. Inner pipe head; 11. Transition section. Detailed Implementation

[0027] The present invention is further illustrated below by way of embodiments, but these embodiments are not intended to limit the invention to the scope of the embodiments described. 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.

[0028] See Figures 1-3 As shown, a single-oxygen-channel dual-flow secondary combustion oxygen lance nozzle includes a forged nozzle crown 1, an outer tube, a sliding connector, a baffle plate 9, an inner tube, and a secondary combustion nozzle 3. From the outside outwards, the inner tube, sliding connector, and outer tube are arranged in sequence. The outer diameter of the forged nozzle crown 1 is welded to the outer tube. The baffle plate 9 is welded to the oxygen column of the forged nozzle crown 1. The outer diameter of the baffle plate 9 is threaded to the sliding connector. The end of the oxygen column of the forged nozzle crown 1 is welded to the end of the oxygen column of the inner tube head 10. The secondary combustion nozzle 3 obliquely passes through the sides of the outer tube, sliding connector, and inner tube, with one end of the secondary combustion nozzle 3 welded and fixed to the outer tube, and the other end of the secondary combustion nozzle 3 welded and fixed to the inner tube.

[0029] Furthermore, the outer tube is welded to the outer copper tube 2 and the outer tube 4. The end of the outer copper tube 2 is connected to the forged nozzle crown 1. The side wall of the outer copper tube 2 is connected to the secondary combustion nozzle 3. The inner tube is welded to the inner tube head 10, the transition section 11 and the sealing tube 7 in sequence. The inner tube head 10 is welded to the secondary combustion nozzle 3.

[0030] Furthermore, the sliding pipe is welded together by sliding pipe 5 and sliding pipe 6, and the other end of sliding pipe 5 is connected to the baffle plate 9 by thread.

[0031] Furthermore, the forged nozzle crown 1, the baffle plate 9, and the inner tube head 10 are all forged.

[0032] Furthermore, the number of secondary combustion nozzles 3 is twice the number of oxygen columns.

[0033] Furthermore, the angle between the secondary combustion nozzle 3 and the axis is 30° to 40°.

[0034] This invention provides a single-oxygen-channel, dual-flow oxygen lance nozzle structure suitable for converter steelmaking. The lance body remains a three-layer steel pipe structure with only one oxygen inlet, central oxygen flow, annular water inlet, and peripheral water return, similar to existing converter oxygen lance nozzles. The difference lies in the nozzle crown. Existing nozzles, due to their specific shape, could only be cast. This invention employs a new design, dividing the front section of the nozzle into a forged nozzle crown 1, a baffle plate 9, and an inner tube head 10, all manufactured using forging methods. This significantly improves the nozzle's strength and extends its service life. Figure 1 and Figure 2As shown, the oxygen lance nozzle structure, viewed from the left along the axis, consists of a copper forged nozzle crown 1 welded to an external copper pipe 2, and an external copper pipe 2 welded to an external connecting pipe 4. A baffle plate 9 is welded to the oxygen column of the forged nozzle crown 1. The other end of the baffle plate 9 is threaded to one end of the sliding connecting pipe 5. A sealing ring 8 is embedded in the groove of the sealing connecting pipe 7. An obliquely drilled hole penetrates the external copper pipe 2, the sliding connecting pipe 5, and the inner tube head 10. The secondary combustion auxiliary nozzle (secondary combustion nozzle 3) is an independent copper pipe that penetrates the outer wall of the external copper pipe 2, the sliding connecting pipe 5, and the inner tube head 10. One end of the secondary combustion nozzle 3 is welded to the outer wall of the external copper pipe 2, and the other end is welded to the inner wall of the inner tube head 10. The contact position between the secondary combustion nozzle 3 and the sliding connecting pipe 5 does not require welding, and the gap is small, which does not affect the cooling of the inlet and outlet water. Only the two ends of the secondary combustion nozzle 3 need to be welded and fixed, respectively to the external copper pipe 2 and the inner pipe head 10. The secondary combustion nozzle 3 and the sliding pipe 5 do not need to be welded. The impact on the inlet and outlet water of the cooling water can be ignored here.

[0035] Sliding pipe 1 5 is welded to sliding pipe 2 6, the oxygen column end of the inner pipe head 10 is welded to the oxygen column end of the forged nozzle crown 1, the other end of the inner pipe head 10 is welded to the transition section 11, and the transition section 11 is welded to the sealing pipe 7.

[0036] This dual-flow oxygen lance nozzle has two types of oxygen nozzles: a main flow oxygen nozzle and a secondary flow oxygen nozzle. The oxygen stream ejected from the main flow nozzle (oxygen column) has the same function as the original oxygen lance: to raise the temperature, reduce carbon content, stir the molten pool, and accelerate slag formation.

[0037] The number of secondary flow nozzles (i.e., secondary combustion nozzle 3) is relatively large, usually twice that of the main flow nozzles or twice that of the main flow nozzles excluding the center nozzle.

[0038] The secondary orifice (i.e., secondary combustion nozzle 3) is a straight cylinder with an inclination angle of 30° to 40°, resulting in good secondary combustion performance and no impact on furnace lining life was observed. Its function is to spray a relatively dispersed oxygen stream.

[0039] In this invention, oxygen is supplied from the inner tube of the oxygen lance into the inner tube head 10, and then to the main oxygen flow orifice of the forging nozzle crown 1. 80% to 85% of the total oxygen supply is ejected through the main oxygen flow orifice, and this portion of the oxygen jet enters the furnace for decarburization. The remaining 15% to 20% of the total oxygen supply is ejected through the secondary combustion nozzle 3 via the auxiliary oxygen flow orifice. The auxiliary flow orifice has a larger opening angle, resulting in a more dispersed oxygen flow. This portion of the oxygen jet reacts with carbon monoxide in the furnace to generate a large amount of heat. This heat is generated in the steel-slag emulsion of the converter foam slag, resulting in good absorption and a very high increase in thermal efficiency. The converter's own heat is fully utilized, thereby increasing the converter's scrap ratio.

[0040] The number of auxiliary flow nozzles is larger, typically twice that of the main flow nozzles; for example, the main flow nozzles have 3 nozzles, and the auxiliary flow nozzles have 6. Alternatively, the main flow nozzles may have 4 nozzles, and the auxiliary flow nozzles 8. In this embodiment, the main oxygen flow nozzles have 5, and the number of auxiliary flow nozzles is twice that excluding the central nozzle of the main oxygen flow nozzles, i.e., 8. The angle of the secondary combustion nozzle 3 on its axis is the same as the inclination of the inclined drilled holes of the external copper pipe 2, the sliding pipe 5, and the inner pipe head 10, at 35°. This results in good secondary combustion performance, and no impact on the furnace lining life has been observed.

[0041] Traditional secondary combustion oxygen lance nozzles have a thin corner at the connection between the auxiliary oxygen flow orifice and the side wall of the lance body, making them difficult to manufacture and requiring high precision. Furthermore, the high-temperature combustion and oxygen flow cause frictional wear, slag inclusions, and thermal corrosion, reducing the lifespan of the secondary combustion oxygen lance nozzle. This invention replaces the original one-piece thin-walled secondary combustion auxiliary orifice nozzle with an independent embedded secondary combustion auxiliary orifice nozzle design. This structure firstly optimizes the forming process by changing from casting to forging, significantly improving product performance and nozzle strength. Secondly, the use of an independent embedded copper tube reduces machining precision and avoids the easy penetration of thin-walled holes during processing, greatly improving the yield rate.

[0042] This invention discloses a novel single-oxygen-channel dual-flow secondary combustion oxygen lance nozzle. Its forming process changes from casting to forging, which greatly improves the nozzle strength and extends its service life. It has a simple structure, is easy to process and manufacture, and does not require changes to the original oxygen lance inner, middle and outer tubes. The oxygen lance nozzle can be directly replaced, making it more convenient for widespread use.

[0043] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0044] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A single-channel dual-flow secondary combustion oxygen lance nozzle, characterized in that, The device includes a forged nozzle crown, an outer tube, a sliding connector, a baffle plate, an inner tube, and a secondary combustion nozzle. From the outside out, the components are the inner tube, the sliding connector, and the outer tube. The outer diameter of the forged nozzle crown is welded to the outer tube. The baffle plate is welded to the oxygen column of the forged nozzle crown. The outer diameter of the baffle plate is threaded to the sliding connector. The end of the oxygen column of the forged nozzle crown is welded to the end of the oxygen column of the inner tube head. The secondary combustion nozzle is obliquely inserted through the sides of the outer tube, the sliding connector, and the inner tube. One end of the secondary combustion nozzle is welded and fixed to the outer tube, and the other end is welded and fixed to the inner tube.

2. The single-oxygen-channel dual-flow secondary combustion oxygen lance nozzle according to claim 1, characterized in that, The outer tube is welded to the outer connecting tube by an external copper tube. The end of the external copper tube is connected to the forged nozzle crown. The side wall of the external copper tube is connected to the secondary combustion nozzle. The inner tube is welded to the inner tube head, transition section and sealing connecting tube in sequence. The inner tube head is welded to the secondary combustion nozzle.

3. The single-oxygen-channel dual-flow secondary combustion oxygen lance nozzle according to claim 1, characterized in that, The sliding pipe is welded together by sliding pipe one and sliding pipe two, and the other end of sliding pipe one is connected to a baffle plate by thread.

4. The single-oxygen-channel dual-flow secondary combustion oxygen lance nozzle according to claim 1, characterized in that, The forged nozzle crown, water baffle, and inner tube head are all forged.

5. The single-oxygen-channel dual-flow secondary combustion oxygen lance nozzle according to claim 1, characterized in that, The number of secondary combustion nozzles is twice the number of oxygen columns.

6. The single-oxygen-channel dual-flow secondary combustion oxygen lance nozzle according to claim 1, characterized in that, The angle between the secondary combustion nozzle and the axis is 30°-40°.

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