Blowing ignition method of converter

Abstract

The invention provides a blowing ignition method of a converter. The blowing ignition method comprises the following steps: acquiring molten iron information and scrap steel information; according to the obtained molten iron information and the obtained scrap steel information, the state of molten iron and the state of scrap steel are judged, and the state of the molten iron and the state of the scrap steel comprise the normal state and the abnormal state; when the state of the molten iron and the state of the scrap steel are both normal states, a first working condition is adopted, and a first blowing model corresponding to the first working condition is selected to complete a blowing ignition step; when the state of the scrap steel is the abnormal state or the state of the molten iron is the abnormal state, a second working condition is determined, and a second blowing model corresponding to the second working condition is selected to complete the blowing ignition step; and when the state of the scrap steel and the state of the molten iron are both abnormal states, a third working condition is determined, and a third blowing model corresponding to the third working condition is selected to complete the blowing ignition step. The ignition success rate of the converter can be increased.

Description

Technical Field

[0001] The invention relates to the technical field of converter steelmaking, in particular to a converter opening and ignition method. Background Art

[0002] The oxygen supply method for oxygen converter steelmaking is mainly to blow oxygen directly into the molten pool. When the supersonic oxygen flow contacts the metal, a large flame is generated, commonly known as ignition. If there is a large amount of solids on the surface of the liquid metal, it will hinder the oxygen flow from contacting the liquid metal, resulting in ignition failure. The following are the common reasons for unsuccessful ignition:

[0003] (1) The slag is not cleanly skimmed off the molten iron, and the slag floats on the surface after entering the converter with the molten iron. (2) There is too much light and thin material in the scrap steel, which floats on the surface. (3) The scrap steel entering the furnace is mixed with sintered ore and slag steel, which floats on the surface of the furnace entrance. (4) After the slag retention operation, a large amount of slag accumulates on the surface.

[0004] When ignition is unsuccessful, a large amount of FeO will accumulate on the liquid surface. During the smelting process, a large number of CO bubbles will be generated as decarburization proceeds, leading to large splashing. The splashing will cause a series of accidents such as steel material loss, poor slagging, gun burning, and equipment damage. Unsuccessful ignition will also cause a large amount of oxygen to accumulate in the converter flue. When the oxygen and CO in the flue reach a certain mixing ratio, a serious explosion accident will occur. Summary of the Invention

[0005] In response to the technical problems raised in the above background technology, the present invention provides a method for igniting a converter by blowing, which can improve the success rate of ignition.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for opening and igniting a converter comprises the following steps:

[0008] S1, obtain molten iron information and scrap steel information;

[0009] S2, judging the state of the molten iron and the state of the scrap according to the acquired molten iron information and the acquired scrap information, wherein the state of the molten iron and the state of the scrap include a normal state and an abnormal state;

[0010] S3, when the states of the molten iron and the scrap steel are both normal, which is a first operating condition, selecting a first blow start model corresponding to the first operating condition to complete the blow start ignition step;

[0011] When the state of the scrap steel is abnormal or the state of the molten iron is abnormal, it is a second operating condition, and a second blowing model corresponding to the second operating condition is selected to complete the blowing and ignition step;

[0012] When the state of the scrap steel and the state of the molten iron are both abnormal, it is the third operating condition, and the third blowing model corresponding to the third operating condition is selected to complete the blowing ignition step.

[0013] Furthermore, in step S1, the molten iron information includes the amount of molten iron added, the composition of each element in the molten iron, the molten iron temperature and the slag thickness on the surface of the molten iron; the scrap steel information includes the type of scrap steel and the proportion of scrap steel categories.

[0014] Furthermore, in step S2, the method for determining the state of the molten iron and the state of the scrap steel based on the acquired molten iron information and scrap steel information is as follows:

[0015] The amount of molten iron added, the composition of each element in the molten iron, the molten iron temperature, the slag thickness on the molten iron surface, the scrap type, and the scrap type ratio are processed to obtain the molten iron consumption, the slag thickness on the molten iron surface, the scrap quality, and the mass ratio of light scrap in the scrap;

[0016] When any of the following conditions occurs: molten iron temperature <1340℃, molten iron consumption <830kg / t, or slag thickness on the molten iron surface >10cm, it indicates that the state of the molten iron is abnormal; otherwise, the state of the molten iron is normal; when the scrap steel quality is poor, it indicates that the state of the scrap steel is abnormal; otherwise, the state of the scrap steel is normal.

[0017] Furthermore, when the mass ratio of light scrap steel in the scrap steel is greater than 30% or when the number of suctions of the electric suction cup per unit time exceeds a preset value, it indicates that the quality of the scrap steel is poor.

[0018] Furthermore, the first blowing model controls the ignition operation according to the following steps:

[0019] Step 1: Adjust the oxygen lance position to 4000mm and open the oxygen lance. The oxygen flow of the oxygen lance is 0 in the initial state, and then click to start blowing;

[0020] Step 2: Lower the oxygen gun position to 2600mm and adjust the oxygen flow rate of the oxygen gun to 25000m 3 / h after blowing for 0~20s;

[0021] Step 3: Keep the oxygen gun position at 2600mm and adjust the oxygen flow rate of the oxygen gun to 28000m 3 / h post-blowing 21-40s;

[0022] Step 4: Lower the oxygen gun position to 2400mm and adjust the oxygen flow rate of the oxygen gun to 32600m 3 / h after blowing for 41 to 60 seconds.

[0023] Furthermore, the second blowing model controls the ignition operation according to the following steps:

[0024] Step 1: Open the nitrogen valve to introduce nitrogen for 20 seconds, with a nitrogen flow rate of 45000m 3 / h, and adjust the position of the oxygen lance during this process. When the oxygen lance position drops from 9000mm to 5000mm, close the nitrogen valve. When the oxygen lance position is at 4000mm, open the oxygen lance. In the initial state, the oxygen flow rate of the oxygen lance is 0. Click to start blowing;

[0025] Step 2: Lower the oxygen gun position to 2600mm and adjust the oxygen flow rate of the oxygen gun to 24600m 3 / h after blowing for 0~20s;

[0026] Step 3: Keep the oxygen gun position at 2600mm and adjust the oxygen flow rate of the oxygen gun to 28300m 3 / h after blowing for 21 to 40 seconds.

[0027] Furthermore, the third blowing model controls the ignition operation according to the following steps:

[0028] Step 1: Open the nitrogen valve to introduce nitrogen for 20 seconds. During this process, when the oxygen gun position drops from 9000mm to 5000mm, the nitrogen flow rate is maintained at 45000m 3 / h, when the oxygen lance reaches 5000mm, click to start blowing; then continue to lower the oxygen lance to 4000mm, at this time adjust the nitrogen flow to 15000m 3 / h later, the oxygen gun is opened and the oxygen flow rate of the oxygen gun is 0 in the initial state;

[0029] Step 2: When the oxygen lance position is adjusted to 2600mm, nitrogen and oxygen mixed blowing is used for blowing from 0 to 20 seconds. During this process, the oxygen flow rate of the oxygen lance is 24600m 3 / h, nitrogen flow rate is 16000m 3 / h;

[0030] Step 3: Keep the oxygen lance at 2600mm and use nitrogen and oxygen mixed blowing for 21s to 40s. During this process, the oxygen flow rate of the oxygen lance is 26000m 3 / h, nitrogen flow rate is 18000m 3 / h.

[0031] Due to the adoption of the above technical solution, the present invention has the following beneficial effects:

[0032] The converter start-blowing ignition method of the present invention judges the state of the molten iron and the scrap steel based on the acquired molten iron information and scrap steel information, selects the corresponding start-blowing model according to the different states of the molten iron and scrap steel to complete the start-blowing ignition steps, reduces the influence of the abnormal state of the molten iron and scrap steel on the ignition success rate, thereby improving the ignition success rate and reducing the influence of abnormal start-blowing ignition on production efficiency; at the same time, it avoids damage to spare parts such as the oxygen lance copper head due to unsuccessful ignition, saving the spare parts cost of the oxygen lance copper head. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The present invention is a flow chart of a converter opening and ignition method according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0035] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a central component. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a central component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a central component. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0037] See Figure 1 A preferred embodiment of the present invention provides a method for opening and igniting a converter, comprising the following steps:

[0038] S1, obtain molten iron information and scrap steel information.

[0039] In this embodiment, molten iron information includes the amount of molten iron added, the composition of various elements in the molten iron, the molten iron temperature, and the slag thickness on the molten iron surface. This information can be obtained by operators sampling and testing the molten iron at the desulfurization station. Scrap information includes the scrap type and the percentage of scrap types. This information can be obtained by operators sampling and testing the scrap.

[0040] S2, judging the state of the molten iron and the state of the scrap steel based on the acquired molten iron information and scrap steel information, wherein the state of the molten iron and the state of the scrap steel include a normal state and an abnormal state.

[0041] Specifically, the amount of molten iron added (i.e., the mass of the molten iron added), the composition of each element in the molten iron, the temperature of the molten iron, the thickness of the slag on the surface of the molten iron, the type of scrap steel and the proportion of scrap steel categories are processed to obtain the molten iron consumption, the thickness of the slag on the surface of the molten iron, the quality of the scrap steel and the mass ratio of light scrap steel in the scrap steel.

[0042] Among them, molten iron consumption refers to the amount of molten iron consumed in the production of unit products (such as molten steel, steel, etc.) during the steel production process. Its calculation formula is:

[0043]

[0044] In this embodiment, molten iron consumption refers to the amount of molten iron consumed to produce a unit product (such as 1 ton of molten steel), and the amount of molten iron consumed is approximately equal to the amount of molten iron added to produce 1 ton of molten steel (the loss of molten iron can be ignored).

[0045] Scrap quality can be assessed using two methods: First, the type of scrap delivered can be used to determine scrap quality. On-site scrap delivery is typically categorized into three types: light and thin material, standard scrap, and Class I heavy scrap. Scrap quality can be determined as poor when the mass ratio of light scrap (light and thin material) exceeds 30%. Second, the quality can be assessed by collecting information from the electric suction cups on the crane. A high suction rate per unit time generally indicates a low scrap density. For example, light and thin material (such as sheet iron and wire rope) has a low density, resulting in a relatively high suction rate. A low suction rate may indicate a high density, such as heavy scrap (such as rails and thick steel plates). A high suction rate indicates a high proportion of light and thin material in the scrap. Light and thin material is generally of lower quality due to its low iron content and the potential for high impurities. A low suction rate indicates a high proportion of heavy scrap, indicating a higher quality and suitable for steelmaking. Therefore, it can be set that the scrap steel quality is poor when the number of suctions of the electric suction cup per unit time exceeds a preset value (for example, 30 suctions).

[0046] When any of the following conditions occurs: molten iron temperature <1340℃, molten iron consumption <830kg / t, or slag thickness on the molten iron surface >10cm, it indicates that the state of the molten iron is abnormal; otherwise, the state of the molten iron is normal; when the scrap steel quality is poor, it indicates that the state of the scrap steel is abnormal; otherwise, the state of the scrap steel is normal.

[0047] S3, when the state of the molten iron and the state of the scrap steel are both normal, which is the first operating condition, the first blowing model corresponding to the first operating condition is selected to complete the blowing ignition step;

[0048] When the state of the scrap steel is abnormal or the state of the molten iron is abnormal (i.e., one of the state of the scrap steel and the state of the molten iron is abnormal), it is the second operating condition, and the second start-blowing model corresponding to the second operating condition is selected to complete the start-blowing ignition step;

[0049] When the states of the scrap steel and the molten iron are both abnormal, it is the third operating condition, and the third blowing model corresponding to the third operating condition is selected to complete the blowing ignition step.

[0050] The first blow model controls the ignition operation according to the following steps, as shown in Table 1:

[0051] Step 1: Adjust the oxygen lance position to 4000mm and open the oxygen lance. The oxygen flow of the oxygen lance is 0 in the initial state, and then click to start blowing;

[0052] Step 2: Lower the oxygen gun position to 2600mm and adjust the oxygen flow rate of the oxygen gun to 25000m 3 / h after blowing for 0~20s;

[0053] Step 3: Keep the oxygen gun position at 2600mm and adjust the oxygen flow rate of the oxygen gun to 28000m 3 / h post-blowing 21-40s;

[0054] Step 4: Lower the oxygen gun position to 2400mm and adjust the oxygen flow rate of the oxygen gun to 32600m 3 / h after blowing for 41 to 60 seconds.

[0055] Table 1

[0056]

[0057] The second blow-on model controls the ignition operation according to the following steps, as shown in Table 2:

[0058] Step 1: Open the nitrogen valve to introduce nitrogen for 20 seconds, with a nitrogen flow rate of 45000m 3 / h, and adjust the position of the oxygen lance during this process. When the oxygen lance position drops from 9000mm to 5000mm, close the nitrogen valve. When the oxygen lance position is at 4000mm, open the oxygen lance. In the initial state, the oxygen flow rate of the oxygen lance is 0. Click to start blowing;

[0059] Step 2: Lower the oxygen gun position to 2600mm and adjust the oxygen flow rate of the oxygen gun to 24600m 3 / h after blowing for 0~20s;

[0060] Step 3: Keep the oxygen gun position at 2600mm and adjust the oxygen flow rate of the oxygen gun to 28300m 3 / h after blowing for 21 to 40 seconds.

[0061] Table 2

[0062]

[0063]

[0064] The third blow-on model controls the ignition operation according to the following steps, as shown in Table 3:

[0065] Step 1: Open the nitrogen valve to introduce nitrogen for 20 seconds. During this process, when the oxygen gun position drops from 9000mm to 5000mm, the nitrogen flow rate is maintained at 45000m 3 / h, when the oxygen lance reaches 5000mm, click to start blowing; then continue to lower the oxygen lance to 4000mm, adjust the nitrogen flow to 15000m 3 / h later, the oxygen gun is opened and the oxygen flow rate of the oxygen gun is 0 in the initial state;

[0066] Step 2: When the oxygen lance position is adjusted to 2600mm, nitrogen and oxygen mixed blowing is used for blowing from 0 to 20 seconds. During this process, the oxygen flow rate of the oxygen lance is 24600m 3 / h, nitrogen flow rate is 16000m 3 / h;

[0067] Step 3: Keep the oxygen lance at 2600mm and use nitrogen and oxygen mixed blowing for 21s to 40s. During this process, the oxygen flow rate of the oxygen lance is 26000m 3 / h, nitrogen flow rate is 18000m 3 / h.

[0068] Table 3

[0069]

[0070] At present, the converter ignition method according to the embodiment of the present invention has been put into use in the 7# and 8# furnaces (150t converters) in the third zone of Liuzhou Iron and Steel Converter Plant, and is running stably.

[0071] Among them, the Liugang converter No. 7 converter has the furnace number 3719713, and the molten iron temperature is 1287℃. It is judged that the molten iron temperature is <1340℃, the molten iron state is abnormal, and the scrap steel state is normal. The second blowing model is selected for blowing and ignition. The oxygen content reaches 6% in 75 seconds, and the carbon monoxide content reaches 12% in 91 seconds. The ignition is normal.

[0072] Furnace number 3719718, molten iron temperature 1254℃, it is judged that the molten iron temperature is <1340℃, the molten iron state is abnormal, the mass ratio of light scrap steel in this furnace scrap steel is >30%, the scrap steel state is abnormal, the third blowing model is selected for blowing and ignition, the oxygen content reaches 6% in 56 seconds, the carbon monoxide content reaches 12% in 88 seconds, and the ignition is normal.

[0073] Heat number 481809, molten iron temperature 1381°C, determined that the molten iron temperature, molten iron condition, and scrap condition were normal. The first blow model was selected for blow ignition. The oxygen content reached 6% in 103 seconds, and the carbon monoxide content reached 12% in 140 seconds, indicating normal ignition. Table 4 also shows some examples of the converter blow ignition method after commissioning, where "Model Selection" indicates the first blow model, "2" indicates the second blow model, and "3" indicates the third blow model.

[0074] Table 4

[0075]

[0076]

[0077] Practice shows that after the start-up and ignition method of the converter according to the embodiment of the present invention was put into use, statistics were collected based on the results of one year of operation. The number of abnormal start-up and ignition of converters No. 7 and 8 (the ignition time exceeded 40s, and the ignition time was the time period from the ignition of the oxygen lance gas outlet to the normal ignition) was reduced from 16 times / 1,000 furnaces to 3 times / 1,000 furnaces. The phenomenon of carbon-oxygen cross-lifting in the dry dust removal of the converter was basically eliminated, and the service life of the converter oxygen lance increased by 52%.

[0078] The converter start-blowing ignition method of the present invention judges the state of the molten iron and the scrap steel based on the acquired molten iron information and scrap steel information, selects the corresponding start-blowing model according to the different states of the molten iron and scrap steel to complete the start-blowing ignition steps, reduces the influence of the abnormal state of the molten iron and scrap steel on the ignition success rate, thereby improving the ignition success rate and reducing the influence of abnormal start-blowing ignition on production efficiency; at the same time, it avoids damage to spare parts such as the oxygen lance copper head due to unsuccessful ignition, saving the spare parts cost of the oxygen lance copper head.

[0079] The above description is a detailed description of the preferred embodiments of the present invention, but the embodiments are not intended to limit the scope of the patent application of the present invention. Any equivalent changes or modifications completed under the technical spirit suggested by the present invention should fall within the patent scope covered by the present invention.

Claims

1. A method for igniting a converter, characterized in that: The following steps are involved: S1, obtain molten iron information and scrap steel information; S2, judging the state of the molten iron and the state of the scrap according to the acquired molten iron information and the acquired scrap information, wherein the state of the molten iron and the state of the scrap include a normal state and an abnormal state; S3, when the states of the molten iron and the scrap steel are both normal, which is a first operating condition, selecting a first blow start model corresponding to the first operating condition to complete the blow start ignition step; When the state of the scrap steel is abnormal or the state of the molten iron is abnormal, it is a second operating condition, and a second blowing model corresponding to the second operating condition is selected to complete the blowing and ignition step; When the state of the scrap steel and the state of the molten iron are both abnormal, it is the third operating condition, and the third blowing model corresponding to the third operating condition is selected to complete the blowing ignition step.

2. The method for igniting a converter according to claim 1, wherein: In step S1, the molten iron information includes the amount of molten iron added, the composition of each element in the molten iron, the molten iron temperature and the slag thickness on the surface of the molten iron; the scrap steel information includes the scrap steel type and the proportion of scrap steel categories.

3. The method for starting blowing and igniting a converter according to claim 2, wherein: In step S2, the method for determining the state of the molten iron and the state of the scrap steel based on the acquired molten iron information and scrap steel information is as follows: The amount of molten iron added, the composition of each element in the molten iron, the molten iron temperature, the slag thickness on the molten iron surface, the scrap type, and the scrap type ratio are processed to obtain the molten iron consumption, the slag thickness on the molten iron surface, the scrap quality, and the mass ratio of light scrap in the scrap; When any of the following conditions occurs: molten iron temperature <1340℃, molten iron consumption <830kg / t, or slag thickness on the molten iron surface >10cm, it indicates that the state of the molten iron is abnormal; otherwise, the state of the molten iron is normal; when the scrap steel quality is poor, it indicates that the state of the scrap steel is abnormal; otherwise, the state of the scrap steel is normal.

4. The method for starting blowing and igniting a converter according to claim 3, wherein: When the mass ratio of light scrap steel in the scrap steel is greater than 30% or when the number of suctions by the electric suction cup per unit time exceeds a preset value, it indicates that the quality of the scrap steel is poor.

5. The method for starting blowing and igniting a converter according to claim 3, wherein: The first blow-on model controls the ignition operation according to the following steps: Step 1: Adjust the oxygen lance position to 4000mm and open the oxygen lance. The oxygen flow of the oxygen lance is 0 in the initial state, and then click to start blowing; Step 2: Lower the oxygen gun position to 2600mm and adjust the oxygen flow rate of the oxygen gun to 25000m 3 / h after blowing for 0~20s; Step 3: Keep the oxygen gun position at 2600mm and adjust the oxygen flow rate of the oxygen gun to 28000m 3 / h post-blowing 21-40s; Step 4: Lower the oxygen gun position to 2400mm and adjust the oxygen flow rate of the oxygen gun to 32600m 3 / h after blowing for 41 to 60 seconds.

6. The method for starting blowing and igniting a converter according to claim 3, wherein: The second opening blowing model controls the ignition operation according to the following steps: Step 1: Open the nitrogen valve to introduce nitrogen for 20 seconds, with a nitrogen flow rate of 45000m 3 / h, and adjust the position of the oxygen lance during this process. When the oxygen lance position drops from 9000mm to 5000mm, close the nitrogen valve. When the oxygen lance position is at 4000mm, open the oxygen lance. In the initial state, the oxygen flow rate of the oxygen lance is 0. Click to start blowing; Step 2: Lower the oxygen gun position to 2600mm and adjust the oxygen flow rate of the oxygen gun to 24600m 3 / h after blowing for 0~20s; Step 3: Keep the oxygen gun position at 2600mm and adjust the oxygen flow rate of the oxygen gun to 28300m 3 / h after blowing for 21 to 40 seconds.

7. The method for starting blowing and igniting a converter according to claim 3, wherein: The third opening and blowing model controls the ignition operation according to the following steps: Step 1: Open the nitrogen valve to introduce nitrogen for 20 seconds. During this process, when the oxygen gun position drops from 9000mm to 5000mm, the nitrogen flow rate is maintained at 45000m 3 / h, when the oxygen lance reaches 5000mm, click to start blowing; then continue to lower the oxygen lance to 4000mm, at this time adjust the nitrogen flow to 15000m 3 / h and open the oxygen gun. The oxygen flow rate of the oxygen gun is 0 in the initial state; Step 2: When the oxygen lance position is adjusted to 2600mm, nitrogen and oxygen mixed blowing is used for blowing from 0 to 20 seconds. During this process, the oxygen flow rate of the oxygen lance is 24600m 3 / h, nitrogen flow rate is 16000m 3 / h; Step 3: Keep the oxygen lance at 2600mm and use nitrogen and oxygen mixed blowing for 21s to 40s. During this process, the oxygen flow rate of the oxygen lance is 26000m 3 / h, nitrogen flow rate is 18000m 3 / h.

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