Internal-direct-flow and external-spiral-flow type efficient dephosphorization oxygen lance nozzle

Abstract

The utility model belongs to the technical field of ferrous metallurgy, and relates to an inner-direct-flow and outer-spiral-flow type efficient dephosphorization oxygen lance nozzle. The outer spiral-flow type spray pipe and the inner straight-flow type spray pipe are arranged at the bottom of the spray head, and parameter requirements of the spray pipes are set. The internal direct-flow oxygen jet flow can quickly penetrate through the molten pool to form a deeper impact pit, and the external rotational-flow oxygen forms a rotating air flow on the surface of the molten pool to drive molten pool liquid to do circular motion, so that the liquid in the molten pool is more sufficiently stirred in the composite flowing mode; compared with a traditional direct-flow oxygen lance, the internal direct-flow and external rotational-flow oxygen lance can enable components and temperature in a molten pool to be more uniform, chemical reaction in the steelmaking process can be more fully carried out, and the quality stability of molten steel is improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of steel metallurgy, concretely relates to a high -efficient dephosphorization oxygen lance nozzle of inner straight flow outside whirl -flow formula. TECHNICAL BACKGROUND

[0002] In the process of top-blown converter steelmaking (BOF), it is critical to form molten slag with suitable composition (such as basicity and FeO content), because dephosphorization mainly depends on the slag composition, the temperature in the furnace, and the kinetics and mass transfer processes of the mixing of liquid metal and slag. During the blowing process, carbon oxidation generates carbon monoxide gas and attempts to escape from the slag, thereby causing volume expansion, which is usually referred to as slag foaming; this foam provides an extremely broad interfacial area between the slag, metal, and gas phases, which strongly promotes interfacial reactions and improves the dephosphorization effect. The generation and maintenance of slag foam are mainly controlled by the oxygen jet of the oxygen lance, so improving the generation of metal droplets in the foamed slag is a major challenge faced by steel plants to improve the slag-metal interfacial reaction and increase the dephosphorization rate. In addition, the change in the height of the oxygen lance is a key process control means in the blowing process of the steelmaking plant, and by adjusting the height of the oxygen lance, the oxygen distribution between the molten slag and the metal phase can be changed, thereby affecting the chemical reaction. Therefore, the oxygen lance must be properly designed, and the lance position and oxygen flow rate must be controlled during the blowing process to improve the efficiency of the steelmaking process and improve the quality of the produced steel.

[0003] The hole type (such as a Laval hole type) of the oxygen lance nozzle can make the oxygen reach a supersonic state when it is sprayed out, thereby enhancing the stirring effect of the oxygen and the molten bath and accelerating the chemical reaction. A good nozzle design can allow the oxygen to be uniformly sprayed into the molten bath, improving the utilization rate of the oxygen. If the nozzle is blocked or damaged, the oxygen lance cannot normally deliver oxygen to the molten bath, resulting in insufficient oxygen supply and affecting the efficiency and quality of the entire metallurgical process. Therefore, the design and performance of the oxygen lance nozzle directly determine the oxygen injection effect.

[0004] Currently, the multi-hole Laval oxygen lance nozzle structure widely used by steel enterprises in China is relatively simple, and its characteristics are that the sizes and shapes of the nozzles of the nozzle are the same, and are uniformly distributed around the axis of the oxygen lance; under a given converter capacity, the inclination angle of the nozzles of the traditional structure oxygen lance and the number of nozzles are strictly limited; since the oxygen lance nozzle is designed under a specific pressure ratio and flow rate, it is difficult to change the flow rate of the nozzle of the traditional structure oxygen lance.

[0005] Therefore, the utility model provides a high -efficient dephosphorization oxygen lance nozzle of inner straight flow outside whirl -flow formula, aims at improving the generation of splashing steel liquid during blowing, to accelerate the reaction process, especially dephosphorization reaction, thereby improving the dephosphorization efficiency. UTILITY MODEL CONTENTS

[0006] In view of the above existing technical problems, the utility model provides a kind of inner direct current outer cyclone type high-efficiency dephosphorization oxygen lance nozzle.The nozzle can effectively improve the in-furnace spatter of molten steel, has good slagging effect, and the dephosphorization rate is obviously improved.

[0007] In order to achieve the above object, the technical scheme provided by the utility model is as follows.

[0008] A kind of inner direct current outer cyclone type high-efficiency dephosphorization oxygen lance nozzle, including first pipe body 1;First pipe body 1 outside is equipped with second pipe body 4, and first pipe body 1 and second pipe body 4 between leave first ring gap;The center of the bottom of second pipe body 4 is provided with through-hole 6;Second pipe body 4 outside is equipped with third pipe body 5, and second pipe body 4 and third pipe body 5 between leave second ring gap;First pipe body 1, second pipe body 4 and third pipe body 5 are all cylindrical pipe body;

[0009] The bottom of third pipe body 5 is provided with outer cyclone type nozzle 2, outer cyclone type nozzle 2 passes through the bottom wall of third pipe body 5, second pipe body 4 and first pipe body 1, and is connected with the inside of first pipe body 1, and outer cyclone type nozzle 2 is multiple;

[0010] The bottom of third pipe body 5 is provided with inner direct current type nozzle 3, and inner direct current type nozzle 3 is arranged between every two adjacent outer cyclone type nozzle 2, and inner direct current type nozzle 3 passes through the bottom wall of third pipe body 5, second pipe body 4 and first pipe body 1, and is connected with the inside of first pipe body 1, and inner direct current type nozzle 3 is multiple;

[0011] The distance between the axis of outer cyclone type nozzle 2 and the axis of nozzle is L1, and the distance between the axis of inner direct current type nozzle 3 and the axis of nozzle is L2, and L1 is greater than L2.

[0012] Further, outer cyclone type nozzle 2 and inner direct current type nozzle 3 adopt Laval nozzle.

[0013] Further, the ratio of the throat diameter d1t of outer cyclone type nozzle 2 to the throat diameter d2t of inner direct current type nozzle 3 is d1t / d2t=1.0~1.5.

[0014] Further, the ratio of the outlet diameter d1e of outer cyclone type nozzle 2 to the outlet diameter d2e of inner direct current type nozzle 3 is d1e / d2e=1.0~1.5.

[0015] Further, the angle between the central axis of outer cyclone type nozzle 2 and the central axis of nozzle is α1, and the angle between the central axis of inner direct current type nozzle 3 and the central axis of nozzle is α2, and α1-α2=3°~5°.

[0016] Further, the rotation angle of outer cyclone type nozzle 2 is β1=8°~12°.

[0017] Further, L1 / L2 = 1.10-1.30.

[0018] Further, the total number of the oxygen lance nozzle is 6, wherein 3 are outer swirl nozzles 2 and 3 are inner straight nozzles 3; the oxygen lance nozzle is suitable for 200-300 ton converter.

[0019] Compared with the prior art, the utility model has the advantages as follows.

[0020] 1) Enhance the stirring effect

[0021] The inner straight oxygen jet can quickly penetrate the molten pool and form a deep impact pit, while the outer swirl oxygen forms a rotating gas flow on the surface of the molten pool, driving the molten pool liquid to do circular motion. This kind of combined flow mode makes the liquid in the molten pool more fully stirred. Compared with the traditional straight oxygen lance, the inner straight outer swirl oxygen lance can make the composition and temperature in the molten pool more uniform, which is beneficial to the chemical reaction in the steelmaking process to proceed more fully, improving the quality stability of the molten steel. For example, in the dephosphorization, desulfurization and other reactions, uniform molten pool composition and temperature help to improve the kinetic conditions of the reaction, making the dephosphorization and desulfurization effect better.

[0022] 2) Improve the oxygen utilization rate

[0023] The high penetration of the inner straight jet enables the oxygen to penetrate deep into the molten pool, fully contact with the molten steel and react; the outer swirl forms a cover layer on the surface of the molten pool, reducing the escape of oxygen, prolonging the residence time of oxygen in the molten pool, thereby improving the utilization rate of oxygen. Under the same oxygen supply amount, the inner straight outer swirl oxygen lance can make more oxygen participate in the steelmaking reaction, thereby improving the steelmaking efficiency, reducing the oxygen consumption and saving the production cost.

[0024] 3) Reduce the spitting loss

[0025] In the steelmaking process, spitting not only causes the loss of molten steel, but also affects the surrounding equipment and environment, increasing the safety hazard. The use of inner straight outer swirl oxygen lance can significantly reduce the probability and amount of spitting, improve the safety and stability of the steelmaking process, reduce the loss of molten steel and improve the metal yield.

[0026] 4) Prolong the service life of the oxygen lance

[0027] Due to the existence of the outer swirl, the scouring effect of oxygen on the oxygen lance nozzle is more uniform, reducing local scouring and wear; at the same time, the inner straight outer swirl blowing method makes the reaction of the molten pool more stable, reducing the thermal shock and erosion of the oxygen lance due to violent reaction. The service life of the oxygen lance nozzle is effectively prolonged, reducing the replacement frequency of the oxygen lance, reducing the equipment maintenance cost and downtime, improving the continuity and efficiency of the steelmaking production. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is the front view of the inner straight flow and outer cyclone type high-efficiency dephosphorization oxygen lance nozzle of the utility model.

[0029] Figure 2 It is the three-dimensional sectional view of the inner straight flow and outer cyclone type high-efficiency dephosphorization oxygen lance nozzle of the utility model.

[0030] Figure 3 It is the plan view of the inner straight flow and outer cyclone type high-efficiency dephosphorization oxygen lance nozzle of the utility model.

[0031] Figure 4 It is the bottom view of the inner straight flow and outer cyclone type high-efficiency dephosphorization oxygen lance nozzle of the utility model.

[0032] Label: 1, first pipe body;2, outer cyclone type nozzle;3, inner straight flow type nozzle;4, second pipe body;5, third pipe body, 6, through hole. DETAILED DESCRIPTION

[0033] The embodiments of the utility model technical scheme will be described in detail below with reference to the drawings, and the following embodiments are only used to more clearly illustrate the technical scheme of the utility model, therefore only as an example, and can not be used to limit the protection scope of the utility model.

[0034] As Figures 1-4 The utility model discloses an inner straight flow and outer cyclone type high-efficiency dephosphorization oxygen lance nozzle, including first pipe body 1;First pipe body 1 outside the sleeve has the second pipe body 4, and first pipe body 1 and the second pipe body 4 between the first ring gap are left;The center of the bottom of second pipe body 4 is provided with through hole 6;Second pipe body 4 outside the sleeve has the third pipe body 5, and second pipe body 4 and the third pipe body 5 between the second ring gap are left;First pipe body 1, second pipe body 4 and third pipe body 5 are all cylindrical pipe body;The bottom of third pipe body 5 is provided with outer cyclone type nozzle 2, and outer cyclone type nozzle 2 passes through the bottom wall of third pipe body 5, second pipe body 4 and first pipe body 1, and is communicated with the inside of first pipe body 1, and outer cyclone type nozzle 2 is 3;The bottom of third pipe body 5 is provided with inner straight flow type nozzle 3, and inner straight flow type nozzle 3 is arranged between every two adjacent outer cyclone type nozzle 2, and inner straight flow type nozzle 3 passes through the bottom wall of third pipe body 5, second pipe body 4 and first pipe body 1, and is communicated with the inside of first pipe body 1, and inner straight flow type nozzle 3 is 3;The distance between the axis of outer cyclone type nozzle 2 and the nozzle axis is L1, and the distance between the axis of inner straight flow type nozzle 3 and the nozzle axis is L2, and L1 is greater than L2.

[0035] The inner direct current oxygen jet can quickly penetrate the molten pool to form a deep impact crater, and the outer rotating oxygen forms a rotating airflow on the surface of the molten pool to drive the molten pool liquid to make a circular motion, and the combined flow mode can more fully stir the liquid in the molten pool; compared with the traditional direct current oxygen lance, the inner direct current and outer rotating oxygen lance can make the composition and temperature in the molten pool more uniform, which is beneficial to the chemical reaction in the steelmaking process to be more sufficient, improves the quality stability of the molten steel, and the uniform molten pool composition and temperature help to improve the kinetic conditions of the reaction, so that the dephosphorization effect is better.

[0036] In one embodiment, the ratio of the throat diameter d 1t of the outer rotating nozzle 2 to the throat diameter d 2t of the inner direct current nozzle 3 (46.4 / 37.6) d 1t / d 2t is 1.2; the ratio of the outlet diameter d 1e of the outer rotating nozzle 2 to the outlet diameter d 2e of the inner direct current nozzle 3 (61.2 / 50.3) d 1e / d 2e is 1.2. The preferred ratio can make the jet formed by the oxygen lance nozzle have a uniform molten pool composition and temperature, which is beneficial to improve the kinetic conditions of the reaction in the dephosphorization, desulfurization and other reactions, so that the dephosphorization and desulfurization effects are better.

[0037] In one embodiment, the angle between the central axis of the outer rotating nozzle 2 and the central axis of the nozzle is α1, the angle between the central axis of the inner direct current nozzle 3 and the central axis of the nozzle is α2, and 16°-12° (α1-α2)=4°; the rotation angle β1 of the outer rotating nozzle 2 is 8°. The advantage of the preferred angle is that the rotating airflow of the outer rotating oxygen on the surface of the molten pool has a relatively uniform and stable impact force on the molten pool, which can effectively inhibit the violent fluctuation and spatter of the molten pool; at the same time, after the inner direct current jet penetrates the molten pool, its energy is also dispersed and buffered to a certain extent, reducing the direct impact on the molten pool.

[0038] In one embodiment, 120 / 100 (L1 / L2)=1.2. The preferred distance L1 / L2 ratio can effectively reduce the rapid fusion between the two types of jets.

[0039] During blowing, oxygen enters the first pipe body 1 of the nozzle from the oxygen branch pipe, and then enters the outer rotating nozzle 2 and the inner direct current nozzle 3, and oxygen is sprayed from the outer rotating nozzle 2 and the inner direct current nozzle 3 to form a supersonic jet; cold water enters the second annular gap through the through hole 6 from the first annular gap.

[0040] To verify the obvious effect of the oxygen lance nozzle of the utility model compared with the traditional oxygen lance nozzle, a comparative experiment under the same smelting conditions was carried out, and the specific sizes of the two oxygen lance nozzles are shown in Table 1.

[0041] Table 1 Geometrical parameters of conventional oxygen lance nozzle for 260t converter and the oxygen lance nozzle of the embodiment.

[0042]

[0043] The steel grade produced during the experiment was plain carbon plate, the molten iron amount was 260t, the scrap steel amount was 30-40t, the total pipe oxygen pressure was 1.3MPa, the working oxygen pressure was 1.05MPa, the oxygen supply flow was 56000Nm 3 / h, the blowing lance position was changed between 2.5m and 3.0m, the process lance position was changed between 2.5m and 2.7m, and the carbon pulling lance position was changed between 2.0m and 2.4m.

[0044] In order to ensure the accuracy of the experiment, the pretreated molten iron composition used in the experiment is shown in Table 2, and there is little difference between each furnace and the average value; the blowing effect of the representative 5 consecutive furnaces is recorded and compared and analyzed.

[0045] Table 2 Comparison of pretreated molten iron composition.

[0046]

[0047] The specific results of the experiment are shown in Tables 3 and 4. Since the steel grade smelted in the experiment is the same, there is little difference in the tapping composition. Table 3 shows the average value of the tapping composition of the conventional oxygen lance nozzle and the oxygen lance nozzle of the embodiment, respectively. The results show that the control of the tapping composition by different oxygen lance nozzles is similar.

[0048] Table 3 Comparison of average tapping composition.

[0049]

[0050] Table 4 Comparison of dephosphorization rate.

[0051]

[0052] From the comparison of the dephosphorization rate in Table 4, it is found that the dephosphorization rate of the 5 consecutive steel grades of the inner straight flow and outer cyclone type high-efficiency dephosphorization oxygen lance nozzle of the embodiment is 3.11% higher than that of the 5 consecutive steel grades of the conventional oxygen lance nozzle. The dephosphorization rate is improved more obviously. The main reason is that after adopting the large inclination angle of the dispersed flow, the jet flow distribution range is larger, the independence of the jet flow is good, the decay speed of the flow is slower, the impact pit area is increased, and the splashing metal droplets formed in the furnace are more dispersed. This has a positive effect on the rapid slagging in the early stage, the time of forming the foamed slag is shortened, and the dephosphorization rate is improved.

[0053] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention.

Claims

1. A high-efficiency dephosphorization oxygen lance nozzle with inner straight flow and outer cyclone, characterized in that, The utility model relates to a kind of oxygen lance nozzle, including first pipe body (1);The first pipe body (1) outside is equipped with second pipe body (4), and first ring gap is left between the first pipe body (1) with the second pipe body (4);The center of the bottom of the second pipe body (4) is provided with through-hole (6);The second pipe body (4) outside is equipped with third pipe body (5), and second ring gap is left between the second pipe body (4) with the third pipe body (5);The first pipe body (1), the second pipe body (4) with the third pipe body (5) are all cylindrical pipe body; The bottom of the third pipe body (5) is provided with outer swirl nozzle (2), the outer swirl nozzle (2) passes through the bottom wall of the third pipe body (5), the second pipe body (4) and the first pipe body (1), and is communicated with the inside of the first pipe body (1), and the outer swirl nozzle (2) is multiple; The bottom of the third pipe body (5) is provided with inner straight-flow nozzle (3), the inner straight-flow nozzle (3) is arranged between every two adjacent outer swirl nozzle (2), the inner straight-flow nozzle (3) passes through the bottom wall of the third pipe body (5), the second pipe body (4) and the first pipe body (1), and is communicated with the inside of the first pipe body (1), and the inner straight-flow nozzle (3) is multiple; The distance between the axis of the outer swirl nozzle (2) and the nozzle axis is L1, the distance between the axis of the inner straight-flow nozzle (3) and the nozzle axis is L2, and L1 is greater than L2.

2. The inner direct current and outer swirling flow high efficiency dephosphorization oxygen lance nozzle according to claim 1 is characterized in that: The outer swirl nozzle (2) and the inner straight-flow nozzle (3) are both Laval nozzle.

3. The inner-DC outer-cyclone high-efficiency dephosphorization oxygen lance nozzle according to claim 1, characterized in that, The ratio of the throat diameter d1t of the outer swirl nozzle (2) and the throat diameter d2t of the inner straight-flow nozzle (3) is d1t / d2t=1.0-1.

5.

4. The inner-DC outer-cyclone high-efficiency dephosphorization oxygen lance nozzle according to claim 1, characterized in that, The ratio of the outlet diameter d1e of the outer swirl nozzle (2) and the outlet diameter d2e of the inner straight-flow nozzle (3) is d1e / d2e=1.0-1.

5.

5. The inner-DC outer-cyclone high-efficiency dephosphorization oxygen lance according to claim 1, characterized in that, The included angle between the central axis of the outer swirl nozzle (2) and the central axis of the nozzle is α1, and the included angle between the central axis of the inner straight-flow nozzle (3) and the central axis of the nozzle is α2, α1-α2=3°-5°.

6. The inner direct current and outer swirling flow high efficiency dephosphorization oxygen lance nozzle according to claim 1 is characterized in that: The rotation angle of the outer swirl nozzle (2) is β1=8°-12°.

7. The inner-DC outer-cyclone high-efficiency dephosphorization oxygen lance according to claim 1, characterized in that, L1 / L2=1.10-1.

30.

8. The inner-DC outer-cyclone high-efficiency dephosphorization oxygen lance according to claim 1, characterized in that, The total number of the nozzle of the oxygen lance nozzle is 6, of which 3 are the outer swirl nozzle (2), and 3 are the inner straight-flow nozzle (3).

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