Anti-splashing control process for converter high-speed iron smelting based on flue gas CO content changes

Abstract

A converter high-iron water consumption smelting anti-splashing control process based on the change of flue gas CO content relates to the technical field of converter high-iron water consumption smelting. It includes solidifying the smelting gun position and process feeding mode according to the change of CO content in the flue gas; optimizing the oxygen gun position control and process feeding mode when the CO content in the flue gas drops sharply; optimizing the oxygen gun position control and process feeding mode when the CO content in the flue gas rises sharply. The beneficial effects of the present invention are: designing a converter anti-splashing control process for CO content changes under high-iron water consumption conditions in the converter → LF refining furnace → billet continuous casting process route, reducing splashing accidents caused by unstable smelting control, reducing steel material consumption losses, and being able to effectively reduce the smelting splashing ratio under high-iron water consumption conditions from the original 4.05% to 0.87%, and solving the problem that there is no similar mature anti-splashing control process on the market in the absence of a sub-gun system and a flue gas analysis system, and it mainly relies on experience judgment.

Description

Technical Field

[0001] The invention relates to the technical field of converter high-iron water consumption smelting, and in particular to a process for controlling splashing prevention of converter high-iron water consumption smelting based on changes in flue gas CO content. Background Art

[0002] Existing patent CN112899432A discloses a converter smelting method based on flue gas analysis to reduce slag dryout. The method comprises the following steps: Step 1: When the converter oxygen blowing rate reaches 55% to 65% of the total oxygen blowing rate, 250-350 kg of pellets are added to the converter; Step 2: After adding the pellets, the CO content in the converter flue gas is measured; Step 3: When the CO content increases by 20% or more, the slag is dryout, and the oxygen lance position is raised by 10 cm, and oxygen blowing is continued for 60 seconds; Step 4: When the CO content increases by less than 20%, the slag is not dryout, and the oxygen lance continues to be blown at the original position. Compared with existing slag dryout monitoring and control methods, this method significantly improves converter dephosphorization efficiency and reduces the problem of molten steel splashing caused by slag dryout.

[0003] Currently, without a secondary lance system or flue gas analysis system, converters primarily rely on empirical methods, such as observing changes in the furnace mouth flame and slag particles, to adjust the lance position and slag addition control during the converter smelting process to prevent smelting splashing. This type of converter smelting splash suppression method has a lag effect, and measures to shorten the splashing duration are generally taken only after splashing occurs. This can easily lead to frequent sudden splashing during converter high-water-consumption smelting. The rapid temperature rise within the furnace also causes prolonged splashing and increased steel consumption. Changes in the CO content in the flue gas during converter smelting directly reflect the reaction and temperature rise within the furnace. Therefore, it is necessary to develop a splash prevention control process for converter high-water-consumption smelting based on changes in flue gas CO content. Summary of the Invention

[0004] The purpose of the present invention is to address the shortcomings and defects in the existing technology, provide a converter high-iron water consumption smelting anti-splashing control process based on the change of flue gas CO content, design a converter anti-splashing control process with CO content changes under high iron water consumption conditions in the converter → LF refining furnace → square billet continuous casting process route, reduce splashing accidents caused by unstable smelting control, reduce steel material loss, and can effectively reduce the smelting splashing ratio under high iron water consumption conditions from the original 4.05% to 0.87%, and solve the problem that there is no similar mature anti-splashing control process on the market in the absence of a sub-gun system and a flue gas analysis system, and it mainly relies on experience judgment.

[0005] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a converter high-iron water consumption smelting anti-splashing control process based on changes in flue gas CO content. The main difficulty of the converter high-iron water consumption smelting anti-splashing control process of the converter → LF refining furnace → square billet continuous casting process route lies in the early prediction of converter splashing and the adjustment of the oxygen lance position and slag addition before splashing occurs. The methods for converter high-iron water consumption smelting anti-splashing control generally include the following methods: S1, solidifying the smelting lance position and process feeding mode according to changes in the CO content in the flue gas; S2, optimizing the oxygen lance position control and process feeding mode when the CO content in the flue gas drops sharply; S3, optimizing the oxygen lance position control and process feeding mode when the CO content in the flue gas rises sharply.

[0006] As a more specific description of the present invention: the solidification smelting gun position and process feeding mode according to the change of CO content in the flue gas are specifically as follows: after the start of blowing, when CO in the flue gas is ≤25%, the gun position is controlled according to the actual smelting gun position of 1.2m; when the smelting time is greater than 4 minutes and CO reaches more than 25%, the gun position is raised by 0.15-0.2m; when the CO is detected to be greater than 47%, the slag is gradually dried, and the gun position is further raised by 0.1-0.3m; when the CO is detected to be greater than 58%, the slag is aggravated by drying, and 100-150Kg of slagging agent is synchronously added until the smelting time reaches 11.5 minutes and then the oxygen gun is slowly lowered to the carbon pulling gun position of 1.1m.

[0007] As a more specific explanation of the present invention: the solidification smelting gun position and process feeding mode according to the change of CO content in the flue gas should be noted: the lime in the smelting process adopts the "silicon" steelmaking mode, the lime is added within 3 minutes of smelting, and the amount of light-burned dolomite added is controlled at 1000-1500 kg to ensure the necessary furnace protection effect.

[0008] As a more specific description of the present invention: the optimization of the oxygen lance position control and process feeding mode when the CO content in the flue gas drops sharply is specifically as follows: when the smelting time is greater than 5 minutes and the CO drops by more than 5% within a 30-second time interval, the lance position drops by 0.10m; if CO continues to drop, the lance position drops another 0.05m; when CO steadily increases, the lance position gradually recovers.

[0009] As a more specific description of the present invention: in the optimization of oxygen lance position control and process feeding mode when the CO content in the flue gas drops sharply, when CO begins to drop and slag particles fly out of the furnace mouth, 100 kg of light-burned dolomite or limestone is added to press the slag.

[0010] As a more specific description of the present invention: the optimization of the oxygen lance position control and process feeding mode when the CO content in the flue gas rises sharply is specifically: when CO>50% and the CO content rises by more than 5% within 30 seconds, when the furnace mouth flame becomes larger, the lance position is raised by 0.1-0.2m, and 200-300kg of ore is added to alleviate the "drying out" phenomenon in the process. When CO no longer rises, the lance position is restored.

[0011] After adopting the above technical scheme, the beneficial effects of the present invention are: designing a converter anti-splashing control process for changing CO content under high iron water consumption conditions in the converter → LF refining furnace → square billet continuous casting process route, reducing splashing accidents caused by unstable smelting control, reducing steel material consumption losses, and being able to effectively reduce the smelting splashing ratio under high iron water consumption conditions from the original 4.05% to 0.87%, and solving the problem that there is no similar mature anti-splashing control process on the market in the absence of a sub-gun system and a flue gas analysis system, and it mainly relies on experience judgment. DETAILED DESCRIPTION

[0012] The technical solution adopted in this specific embodiment is: the main difficulty of the converter high iron water consumption smelting anti-splashing control process in the converter → LF refining furnace → billet continuous casting process route lies in the early prediction of converter splashing and the adjustment of the oxygen lance position and slag addition before splashing occurs. The methods for converter high iron water consumption smelting anti-splashing control are generally as follows:

[0013] S1, solidification smelting gun position and process feeding mode according to the change of CO content in the flue gas:

[0014] 1) After blowing begins and CO in the flue gas is ≤25%, the gun position is controlled according to the actual smelting gun position of 1.2m;

[0015] 2) When the smelting time is greater than 4 minutes and the CO reaches more than 25%, the gun position is raised by 0.15-0.2m;

[0016] 3) When the CO is detected to be greater than 47%, the slag is gradually dried and the gun position is raised by another 0.1-0.3m;

[0017] 4) When the CO is detected to be greater than 58%, the slag drying is aggravated, and 100-150 kg of slagging agent is added simultaneously until the smelting time reaches 11.5 minutes, and then the oxygen lance is slowly lowered to the carbon pulling lance position of 1.1 m.

[0018] The lime in the smelting process adopts the "silicon" steelmaking mode. The lime is added within 3 minutes of smelting, and the amount of light-burned dolomite added is controlled at 1000-1500 kg to ensure the necessary furnace protection effect.

[0019] S2. Optimize the oxygen lance position control and process feeding mode when the CO content in the flue gas drops sharply: if the smelting time is greater than 5 minutes and the CO drops by more than 5% within a 30-second time interval, the lance position will drop by 0.10m. If the CO continues to drop, the lance position will drop another 0.05m. When the CO rises steadily, the lance position will gradually recover. When the CO starts to drop and the slag particles fly out of the furnace mouth, add 100kg of light-burned dolomite or limestone to press the slag.

[0020] S3, optimize the oxygen lance position control and process feeding mode when the CO content in the flue gas rises sharply: when CO>50% and the CO content rises by more than 5% within 30 seconds, and the furnace flame becomes larger, the lance position is raised by 0.1-0.2m, and 200-300kg of ore is added to alleviate the "drying out" phenomenon in the process. When CO no longer rises, the lance position is restored.

[0021] The above description is only used to illustrate the technical solution of the present invention and is not intended to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in this field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A process for controlling water consumption and preventing splashing in converter high-iron smelting based on changes in flue gas CO content, characterized by: The method for controlling splashing during converter high-speed iron smelting is: S1, solidification of smelting gun position and process feeding mode according to the change of CO content in flue gas; S2, optimize the oxygen lance position control and process feeding mode when the CO content in the flue gas drops sharply; S3, optimize the oxygen lance position control and process feeding mode when the CO content in the flue gas rises sharply; The S1 is specifically: 1) After blowing begins and CO in the flue gas is ≤25%, the gun position is controlled according to the actual smelting gun position of 1.2m; 2) When the smelting time is greater than 4 minutes and the CO reaches more than 25%, the gun position is raised by 0.15-0.2m; 3) When the CO is detected to be greater than 47%, the slag is gradually dried and the gun position is raised by another 0.1-0.3m; 4) When the CO content is detected to be greater than 58%, the slag drying is aggravated, and 100-150 kg of slagging agent is added simultaneously until the smelting time reaches 11.5 minutes, and then the oxygen lance is slowly lowered to the carbon pulling lance position of 1.1 m; The S2 is specifically: If the smelting time is greater than 5 minutes and CO drops by more than 5% within a 30-second time interval, the gun position will be lowered by 0.10m. If CO continues to drop, the gun position will be lowered by another 0.05m. When CO steadily increases, the gun position will be gradually restored. The S3 is specifically: When CO>50% and CO content rises by more than 5% within 30 seconds, and the furnace flame becomes larger, the gun position is raised by 0.1-0.2m, and 200-300kg of ore is added to alleviate the "drying out" phenomenon in the process. When CO no longer rises, the gun position is restored.

2. The process for controlling water consumption and splashing prevention in converter high-iron smelting based on flue gas CO content change according to claim 1 is characterized in that: It should be noted that the lime in the S1 smelting process adopts the "silicon" steelmaking mode, the lime is added within 3 minutes of smelting, and the amount of light-burned dolomite added is controlled at 1000-1500 kg to ensure the necessary furnace protection effect.

3. The process for controlling water consumption and splashing prevention in converter high-iron smelting based on flue gas CO content change according to claim 1 is characterized in that: In S2, when CO begins to decrease and slag particles fly out of the furnace mouth, 100 kg of light-burned dolomite or limestone is added to press the slag.