Lime powder screening system and control method

Abstract

The invention belongs to the field of steelmaking, and relates to a lime powder screening system and a control method, the system comprises a screening device installed at a hopper of a belt conveyor transfer station, a replaceable screen plate is arranged, the standard size of screen holes is 10 mm, and lime powder is effectively screened out. The design volume of the ash storage bin is 120 m < 3 >, the ash storage bin is installed in a plant, a high-material-level sensor and an ash bin dust remover are arranged, and safe ash storage and dust prevention are guaranteed. And the closed ash discharging device reduces raised dust. And the interlocking control system ensures the safety and high efficiency of screening, ash discharging and high-material-level emergency treatment. The control method comprises screening preparation, operation starting and stopping, high material level treatment and exception treatment, stable operation of the system is guaranteed, the lime utilization rate is increased, and the steelmaking cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the field of steelmaking and relates to a lime screening powder system and a control method. Background Art

[0002] In the process of steelmaking production, the converter smelting process is one of the key links. A large amount of bulk materials such as lime, dolomite, sinter ore, and fluorite are required to be added for slag making in this process to remove harmful elements such as sulfur and phosphorus in the molten steel, so as to ensure the quality and performance of the molten steel. Among them, lime, as the main slag-making agent, its use effect directly affects the stability of the smelting process and the final quality of the molten steel.

[0003] However, during the transportation, storage, and use of bulk materials such as lime, due to its loose structure and low physical strength, it is easy to break, resulting in a change in the particle size of lime and generating a certain amount of powder. These powders are relatively light in weight, and most of them will be carried away by the flue gas in the furnace under the influence of the rising hot gas flow in the furnace and the negative pressure suction of the primary dust removal system, and enter the primary dust removal system. This not only reduces the amount of lime actually entering the furnace to participate in the reaction, making it impossible to effectively remove harmful elements such as sulfur and phosphorus in the molten iron, but also causes fluctuations in the composition of the molten steel, and it is difficult to accurately control the smelting process, especially the basicity of the slag.

[0004] In addition, these powders are easy to scale and harden when encountering water inside the dust removal equipment, further increasing the load of the primary dust removal system, affecting the dust removal effect, and even possibly causing failures and damages to the dust removal equipment, increasing production costs and maintenance difficulties.

[0005] In the prior art, the material screening link in the converter project is mostly set at the last transfer station of the feeding conveyor belt. Although this method can remove most of the powder in the lime to a certain extent, the lumpy lime after screening will still be pulverized when discharged into the high-level bin on the furnace top, resulting in a small amount of lime powder inevitably entering the converter feeding system. Although this traditional screening method is simple and easy to implement, its effect is limited and cannot meet the high requirements of modern steelmaking production for lime quality and smelting efficiency. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a lime screening powder system and a control method to solve the existing problems.

[0007] To achieve the above purpose, the present invention provides the following technical solution: A lime screening powder system includes a screening device installed at the head hopper of the transfer station of the first steelmaking conveyor belt system in the steel mill. The screening device is configured with a replaceable sieve plate, the standard size of the sieve hole is 10 mm, and the spare sieve hole size is 8 mm;

[0008] It also includes a dust storage bin with a volume of 120 m3 , it is arranged in the workshop between the RH vacuum pump room and the scrap steel pit, and a dust collector for ash bin and a high-level sensor are set on the top of the bin;

[0009] It also includes a closed ash discharging device, which comprises a dust suction port connected to the ash storage bin. The dust suction port is connected to the refining A dust removal system through a pipeline and is equipped with an electric valve;

[0010] This system is also equipped with an interlock control system to realize the following interlock functions:

[0011] a) It is prohibited to start the belt conveyor transportation when the "screening closed" in-place signal lamp of the screening trolley is not on;

[0012] b) When the high-level of the ash storage bin is triggered, the screening function is forced to close;

[0013] c) It is prohibited to carry out screening operation and ash discharging operation simultaneously.

[0014] Optionally, the screening effect of the screening device is that the proportion of lime powder with a particle size < 10mm in the undersize material is less than 10%.

[0015] Optionally, the screening device is equipped with a dual working mode switching mechanism, which can realize:

[0016] Screening position: for screening metallurgical lime;

[0017] Non-screening position: allows the S116 / S117 belt conveyor to transport other materials.

[0018] A control method for a lime screening and powdering system, applicable to a lime screening and powdering system as described above, includes the following steps:

[0019] S1, Preparation for screening metallurgical lime: Confirm that the "screening open" in-place signal lamp of the screening trolley is on; Switch the authority of the screening trolley to the "remote" mode through the remote control interface;

[0020] S2, Start the screening operation: Click the "screening open" button to activate the screening device; Start the S116 belt conveyor for lime feeding;

[0021] S3, Terminate the screening operation: After the lime feeding is completed, click the "screening closed" button; Confirm that the "screening closed" in-place signal lamp is on;

[0022] S4, Emergency treatment for high level: When the high-level sensor of the ash storage bin is triggered, automatically close the screening device; Immediately arrange the ash discharging operation.

[0023] Optionally, step S1 further includes: verifying that there are no other types of auxiliary materials on the belt conveyor; Manually confirm that the actual position of the screening trolley is consistent with the signal lamp status.

[0024] Optionally, when the ash discharging operation is performed: start the dust removal system on the top of the bin; open the electric valve of the dust removal system for refining A; use a fully enclosed suction and discharge vehicle for powder transportation.

[0025] Optionally, it further includes an exception handling program:

[0026] When starting the transportation of non-lime materials when the "screening off" signal is not on: immediately stop the operation of the belt conveyor; mark the current undersize material as scrap; generate a mixing accident record.

[0027] Optionally, the high-level interlock logic of the ash storage bin is as follows:

[0028] When the high-level signal is triggered, the interlock system executes: cut off the power supply of the screening device; lock the screening trolley in the "screening off" position; send an ash discharging instruction to the first converter operation area.

[0029] The beneficial effects of the present invention are as follows:

[0030] Reduce the consumption of lime entering the steelmaking furnace: By screening the lime through this system, the powder part in the lime is effectively removed, improving the utilization rate of lime. Under the condition that the hot metal composition and steel grade process are equivalent, after adding lime screening, the consumption of metallurgical lime entering the converter is significantly reduced compared with the previous index. For example, compared with the cumulative index of 32.02 kg / t from January to November 2023, it can be reduced by 1.2 kg / t.

[0031] Reduce the calcium oxide content in the dust removal ash: Since the screening system effectively removes the powder in the lime, these powders no longer enter the primary dust removal system, thereby reducing the calcium oxide content in the dust removal ash. Specific data shows that the calcium oxide content in the coarse ash is reduced from the original 15.98% to ≤11.98%, and the calcium oxide content in the fine ash is reduced from the original 11.91% to ≤9.5%. This helps to reduce the load of the dust removal equipment and improve the dust removal effect.

[0032] Improve the stability of the smelting process and the quality of molten steel: Since the quality of the lime entering the furnace is improved and the effective components in the lime are more concentrated, it helps to more accurately control the slag basicity, reduce the fluctuation of the molten steel composition, and thus improve the stability of the smelting process and the final quality of the molten steel.

[0033] Reduce environmental pollution: The ash storage bin in the system adopts a fully enclosed ash discharging method and is equipped with a dust collector for the ash bin, effectively reducing the dust during the ash discharging process and protecting the production environment. At the same time, the dust suction port is incorporated into the dust removal pipeline of refining A through a pipeline, further strengthening the dust removal effect and reducing environmental pollution.

[0034] Improving production efficiency and safety: The system has an automatic remote control function, which can remotely control the screening device and the belt conveyor, improving production efficiency. At the same time, the interlock control system in the system ensures safe operation under different working conditions. For example, the belt conveyor transportation is prohibited when the signal light indicating the "screening off" position of the screening trolley is not on, and the screening function is forcibly closed when the high material level in the ash storage bin is triggered, effectively avoiding production accidents.

[0035] Flexibly adapting to different material transportation requirements: The screening device is equipped with a dual working mode switching mechanism, which can flexibly switch between the screening position and the non-screening position. It can be used for screening metallurgical lime and also allows the S116 / S117 belt conveyor to transport other materials, improving the flexibility and adaptability of the system.

[0036] Facilitating maintenance and management: Each component in the system, such as the screening device, the ash storage bin, the enclosed ash discharging device, etc., is reasonably designed, facilitating daily maintenance and management. At the same time, the system is also equipped with an exception handling program, which can take timely measures in case of abnormal situations to reduce losses.

[0037] Other advantages, objectives, and features of the present invention will be described to some extent in the subsequent specification, and to some extent, will be obvious to those skilled in the art based on the study of the following text, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the following specification. Brief Description of the Drawings

[0038] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be described in detail preferably with reference to the accompanying drawings, where:

[0039] Figure 1 is a schematic diagram of the overall system of the present invention.

[0040] Reference numerals: screening device 1, ash storage bin 2, ash discharging device 3. Detailed Embodiments

[0041] The following specific examples illustrate the embodiments of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the drawings provided in the following embodiments only illustrate the basic concept of the present invention schematically, and the following embodiments and the features in the embodiments can be combined with each other without conflict.

[0042] Among them, the attached drawings are only for illustrative purposes, showing only schematic diagrams rather than actual physical diagrams, and should not be construed as limiting the present invention; for better illustration of the embodiments of the present invention, some components in the attached drawings will be omitted, enlarged or reduced, which does not represent the dimensions of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the attached drawings may be omitted.

[0043] In the attached drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "rear", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the attached drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the attached drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0044] Please refer to Figure 1 , which is a specific implementation of a lime sieving powder system and a control method. The system composition includes:

[0045] Sieving device 1: Installed at the head hopper of the transfer station of the No. 1 steelmaking belt conveyor system in the steelmaking plant, equipped with a replaceable sieve plate. The standard size of the sieve holes is 10 mm, and the spare sieve hole size is 8 mm. The sieving device 1 is equipped with a dual working mode switching mechanism, which can flexibly switch between the sieving position (for metallurgical lime sieving) and the non-sieving position (allowing the S116 / S117 belt conveyor to transport other materials).

[0046] Ash storage bin 2: The designed volume is 120 m 3 , arranged in the plant between the RH vacuum pump room and the scrap steel pit. A dust collector for the ash bin and a high-level sensor are provided on the top of the bin to monitor the material level of the ash storage bin 2.

[0047] Enclosed ash discharging device 3: It includes a dust suction port connected to the ash storage bin 2. The dust suction port is connected to the refining A dust removal system through a pipeline and is equipped with an electric valve. During the ash discharging process, start the dust removal system on the top of the bin and the electric valve of the refining A dust removal system, and use a fully enclosed suction and discharge vehicle for powder transportation to reduce dust emission.

[0048] Interlock control system: Realize the following interlock functions: It is prohibited to start the belt conveyor transportation when the "sieving off" in-place signal lamp of the sieving trolley is not on; When the high material level of the ash storage bin 2 is triggered, the sieving function is forced to be closed; It is prohibited to carry out sieving operations and ash discharging operations simultaneously.

[0049] The control method includes:

[0050] S1, Metallurgical Lime Screening Preparation:

[0051] Confirm that the signal light indicating the "Screening Open" position of the screening trolley is on.

[0052] Switch the authority of the screening trolley to the "Remote" mode through the remote control interface.

[0053] Verify that there are no other types of auxiliary materials on the belt conveyor.

[0054] Manually confirm that the actual position of the screening trolley is consistent with the signal light status.

[0055] S2, Start Screening Operation:

[0056] Click the "Screening Open" button to activate the screening device 1.

[0057] Start the S116 belt conveyor for lime feeding.

[0058] S3, Terminate Screening Operation:

[0059] After the lime feeding is completed, click the "Screening Close" button.

[0060] Confirm that the signal light indicating the "Screening Close" position is on.

[0061] S4, Emergency Handling for High Material Level:

[0062] When the high material level sensor of the ash storage bin 2 is triggered, automatically close the screening device 1.

[0063] Immediately arrange for ash discharging operation, and start the electric valves of the top-of-bin dust removal system and the refining A dust removal system.

[0064] S5, Execution of Ash Discharging Operation:

[0065] Start the top-of-bin dust removal system.

[0066] Open the electric valve of the refining A dust removal system.

[0067] Use a fully enclosed suction and discharge vehicle for powder transportation.

[0068] S6, Abnormal Handling Procedure:

[0069] When starting the transportation of non-lime materials without the "Screening Close" signal on, immediately stop the operation of the belt conveyor.

[0070] Mark the current screenings as scrap.

[0071] Generate a record of the mixing accident.

[0072] Example 1: Implementation of the Lime Screening System in the First Steelmaking Plant

[0073] Install a lime screening device 1 at the head hopper of the 2# transfer station at the transfer station (at the head of S116 and the tail of S117 belt conveyors) of the belt conveyor system in a steelmaking plant. The designed volume of the ash storage bin 2 is 120 m 3 , and it is arranged inside the plant (between the RH vacuum pump room and the scrap steel pit). Before loading lime, switch the permission of the screening trolley to the "remote" mode through the remote control interface, and confirm that the "screen open" in-place signal light of the screening trolley is on. Start the S116 belt conveyor to load lime, and the screening device 1 effectively removes the powdered part in the lime. After the lime loading is completed, click the "screen close" button, confirm that the "screen close" in-place signal light is on, and end the screening operation. When the high-level sensor of the ash storage bin 2 is triggered, automatically close the screening device 1 and immediately arrange for ash discharging operation.

[0074] Example 2: Application of Lime Screening System under Multiple Working Conditions

[0075] Install a lime screening system at the transfer station of a similar belt conveyor system in another steelmaking plant. This system is not only used for screening metallurgical lime, but also flexibly switches to the non-screening working position according to production requirements, allowing the S116 / S117 belt conveyors to transport other materials. Before screening metallurgical lime, perform the same operation on the remote control interface, confirm that the "screen open" in-place signal light of the screening trolley is on, and start the belt conveyor for loading. During the screening process, the system monitors the material level of the ash storage bin 2 in real time. When the high-level sensor is triggered, immediately close the screening device 1 and arrange for ash discharging. At the same time, the system is also equipped with an exception handling program to ensure that measures can be taken in a timely manner in case of abnormal situations to reduce losses. In the non-screening working position, the belt conveyor can normally transport other materials, improving the flexibility and adaptability of the system.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not restrictive. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the present technical solution, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A lime powder screening system, characterized in that: It includes a screening device installed at the head hopper of the transfer station of the conveying system of the first steelmaking belt conveyor in the steel mill. The screening device is configured with replaceable sieve plates. The standard size of the sieve holes is 10 mm, and the spare sieve hole size is 8 mm; It also includes a dust storage bin with a volume of 120 m 3 , which is arranged in the plant between the RH vacuum pump room and the scrap steel pit. A dust collector and a high-level sensor are installed on the top of the bin; It also includes a closed ash discharging device. The closed ash discharging device includes a dust suction port connected to the ash storage bin. The dust suction port is connected to the refining A dust removal system through a pipeline and is equipped with an electric valve; This system is also equipped with an interlock control system to achieve the following interlock functions: a) It is prohibited to start the belt conveyor transportation when the "screening closed" in-place signal lamp of the screening trolley is not on; b) When the high material level of the ash storage bin is triggered, the screening function is forced to close; c) It is prohibited to carry out screening operations and ash discharging operations simultaneously.

2. The lime powder screening system according to claim 1, wherein: The screening effect of the screening device is that the proportion of lime powder with a particle size < 10 mm in the screened material is less than 10%.

3. A lime powder screening system according to claim 1, characterized in that, The screening device is equipped with a dual working mode switching mechanism, which can achieve: Screening position: for screening metallurgical lime; Non-screening position: allowing the S116 / S117 belt conveyor to transport other materials.

4. A control method for a lime powder screening system, applicable to a lime powder screening system as described in any one of claims 1 to 3, characterized in that, It includes the following steps: S1, Preparation for screening metallurgical lime: Confirm that the "screening open" in-place signal lamp of the screening trolley is on; Switch the authority of the screening trolley to the "remote" mode through the remote control interface; S2, Start the screening operation: Click the "screening open" button to activate the screening device; Start the S116 belt conveyor for lime feeding; S3, Terminate the screening operation: After the lime feeding is completed, click the "screening closed" button; Confirm that the "screening closed" in-place signal lamp is on; S4, Emergency treatment for high material level: When the high material level sensor of the ash storage bin is triggered, automatically close the screening device; Immediately arrange the ash discharging operation.

5. The control method of a lime sieving powder system according to claim 4, characterized in that, Step S1 also includes: Verifying that there are no other types of auxiliary materials on the belt conveyor; Manually confirming that the actual position of the screening trolley is consistent with the signal lamp status.

6. The control method of a lime powder screening system according to claim 4, characterized in that, When the ash discharging operation is executed: Start the dust removal system on the top of the bin; Open the electric valve of the refining A dust removal system; Use a fully enclosed suction and discharge vehicle for powder transportation.

7. The control method of a lime powder screening system according to claim 4, characterized in that, It also includes an exception handling program: When starting the transportation of non-lime materials when the "screening closed" signal is not on: Immediately stop the operation of the belt conveyor; Mark the current screened material as scrap; Generate a mixing accident record.

8. The control method of a lime powder screening system according to claim 4, characterized in that, The interlock logic for the high material level of the ash storage bin is: When the high material level signal is triggered, the interlock system executes: Cut off the power supply of the screening device; Lock the screening trolley in the "screening closed" position; Send an ash discharging instruction to the first converter operation area.

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