Method for on-line addition of dust to a converter production process

Abstract

This invention relates to a converter production method involving the online addition of converter recovered dust, belonging to the technical field of converter dust for carbon steel smelting. This method combines two methods of adding converter dust: direct online addition of converter recovered dust and offline reprocessing of the recovered dust before indirect addition back to the converter. Both methods are used simultaneously in the converter production process, and specific conditions and steps for each method are provided. Therefore, this method should be able to guide and achieve the real-time online return of recovered dust to the converter, and can be better adapted to actual converter production.

Description

Technical Field

[0001] This invention relates to a production method for adding online dust recovered by dry dust removal equipment during converter production to the converter, belonging to the field of converter flue dust for carbon steel smelting technology. Background Technology

[0002] In existing converter production processes, various types of dust generated during the process are recovered using dry dust collection equipment; this method is also known as converter dry dust collection. Since the dust recovered through converter dry dust collection generally contains a large amount of iron and iron oxide, returning this recovered dust to the converter production process can reduce the production cost of converter smelting.

[0003] The current method for returning dust recovered from dry dust collection in converters to the converter production process is as follows: First, the dust recovered by the dry dust collection equipment is fed into an ash storage silo. Then, the dust is transported by truck to a dedicated dust reprocessing workshop, where specialized equipment cold-presses the dust into spherical shapes. These spherical dust balls are then transported back to the converter production workshop and, via a feeding device, added to the high-level silo in the converter used for adding various auxiliary materials (slagging agents, etc.). In the subsequent converter production process, the dust balls are added to the converter through valves, vibrating feeders, and other equipment, achieving effective dust recovery and utilization.

[0004] Currently known devices also exist that directly return converter dust to the converter, such as the converter smelting system and converter coarse ash feeding device disclosed in Chinese Patent Publication No. CN207828341U, and the converter flue gas dust collection and ash recovery device disclosed in Chinese Patent Publication No. CN207862382U. However, these published documents only roughly provide the equipment and simple concepts for returning converter dust to the converter, without proposing specific methods to adapt to different process requirements in the actual converter production process. Therefore, they lack practical guidance on how to specifically utilize converter dust in the converter production process. Summary of the Invention

[0005] The technical problem to be solved by this invention is to propose a specific process method that can adapt to the process requirements in the actual converter production process.

[0006] The technical solution proposed by the present invention to solve the above-mentioned technical problems is: a converter production method for online addition of converter recovered dust, wherein the converter is equipped with a dry dust removal device and an ash storage bin for storing the dust recovered by the dry dust removal device, and an ash addition bin with a first bulk density V1 is set above the converter for directly storing the dust.

[0007] In the converter production process, when the production plan determines that the dust needs to be added to the converter for that batch, the second bulk density V2 of the dust that needs to be added to the converter production process for that batch is determined according to the production plan; the converter production process includes a first feeding step of adding scrap steel and molten iron to the converter before oxygen blowing and a second feeding step of adding various auxiliary materials to the converter during oxygen blowing.

[0008] The following additional steps are performed in the converter production process:

[0009] 1) After the converter production process begins,

[0010] The third bulk density V3 of the dust recovered by the dry dust removal equipment in the previous converter production process is measured, and the fourth bulk density V4 of the remaining dust in the ash addition bin is measured.

[0011] The second capacity V2 is less than or equal to the first capacity V1 and greater than or equal to the third capacity V3;

[0012] If V3 + V4 < V1, proceed to the next step;

[0013] If V3+V4≥V1 or if the dry dust removal equipment malfunctions, then proceed to step 3).

[0014] 2) Before the first feeding step, the dust recovered by the dry dust removal equipment is first fed into the ash hopper, and then the dust with a first bulk density V is added into the converter through the ash hopper;

[0015] 3) First, the dust collected by the dry dust removal equipment is fed into the ash storage bin, and then the dust in the ash storage bin is shaped into balls;

[0016] 4) In the second feeding step, the dust, which is made into spherical shape, is added to the converter together with the auxiliary materials.

[0017] Furthermore, in step 2),

[0018] If the second capacity V2 is less than the sum of the third and fourth capacities V3 and V4, the dust is added to the converter in one batch.

[0019] If the second capacity V2 is greater than the sum of the third capacity V3 and the fourth capacity V4 but less than twice the sum of the third capacity V3 and the fourth capacity V4, then the dust is added to the converter in two batches at an interval of 25-35 seconds.

[0020] If the second capacity V2 is greater than twice the sum of the third and fourth capacities V3 and V4, the dust is added to the converter in three batches at intervals of 25-35 seconds.

[0021] Furthermore, the rotational speed of the primary dust collector fan in the dry dust removal equipment is controlled according to the following conditions:

[0022] A. At the start of the converter production process, the speed of the primary dust collector fan is controlled to be 15-20% of its rated speed;

[0023] B. When adding the dust before the first feeding step, the speed of the primary dust collector fan is controlled to be 21-25% of its rated speed;

[0024] C. When adding scrap steel in the first feeding step, the speed of the primary dust collector fan is controlled to be 21-25% of its rated speed;

[0025] D. During the addition of molten iron in the first feeding step, the speed of the primary dust collector fan is controlled to be 75-80% of its rated speed;

[0026] E. In the second feeding step, the speed of the primary dust removal fan is controlled to be 100% of the rated speed.

[0027] Furthermore, the opening degree of the secondary dust removal valve of the dry dust removal equipment is controlled according to the following situations:

[0028] A. At the start of the converter production process, the opening degree of the secondary dust removal valve is controlled to be 15-20% of its maximum opening degree;

[0029] B. When adding the dust before the first feeding step, the opening degree of the secondary dust removal valve is controlled to be 21-25% of the maximum opening degree of the secondary dust removal valve;

[0030] C. When adding scrap steel in the first feeding step, the opening degree of the secondary dust removal valve is controlled to be 75-80% of the maximum opening degree of the secondary dust removal valve;

[0031] D. When adding molten iron in the first feeding step, the opening degree of the secondary dust removal valve is controlled to be 81-85% of the maximum opening degree of the secondary dust removal valve;

[0032] E. In the second feeding step, the opening degree of the secondary dust removal valve is controlled to be 100% of the maximum opening degree of the secondary dust removal valve.

[0033] Furthermore, in step 3), the dust in the ash storage silo is output and sent to a special dust reprocessing workshop to be made into spheres, and then the spheres of dust are sent back to the high-level silo of the converter for adding the auxiliary materials.

[0034] The beneficial effects of this invention are: 1. By considering the charging window period in the actual converter production process and organically combining the recovered dust with this charging window period, the recovered dust can be added to the converter in an orderly (rather than blind) manner, thereby enabling the recovered dust to be effectively utilized in converter production; 2. By controlling the dust to be added to the converter in batches at set intervals, the converter production cycle can be controlled to improve converter production efficiency; 3. By dividing the charging steps in the converter production process into stages and controlling the speed of the primary dust removal fan and the opening of the secondary dust removal valve respectively, the recovered dust can be added to the converter when the primary dust removal fan is at a low speed and the secondary dust removal valve is at a high speed. When the secondary dust collector valve is at a low opening, it can be better absorbed and utilized by the converter; 4. By organically combining online (within the converter production workshop) dust recovery and offline (outside the converter production workshop) dust recovery for reprocessing and then returning to the converter, it can be ensured that the converter production can utilize the recovered dust at any time, thereby improving the utilization rate of the recovered dust in converter production; 5) By combining the two methods of adding recovered dust to the converter online and offline reprocessing of recovered dust before indirectly adding it to the converter, both methods can be used simultaneously in the converter production process, thus better adapting to the actual converter production. In summary, this invention has practically and organically combined the real-time online addition of recovered dust to the converter with the existing actual converter production process, and proposed specific methods and steps for real-time online addition of recovered dust to the converter to adapt to the actual converter production process and its process requirements. It should be able to guide and realize the real-time online return of recovered dust to the converter. Attached Figure Description

[0035] The following description, in conjunction with the accompanying drawings, further illustrates a converter production method for online addition of converter dust recovery according to the present invention.

[0036] Figure 1 This is a schematic diagram of the dry dust removal equipment involved in an online converter production method for adding recycled dust to the converter, according to an embodiment.

[0037] Figure 2 This is a logic diagram for controlling the speed of the primary dust collector fan in the dry dust removal equipment involved in the embodiment.

[0038] Figure 3 This is a schematic diagram of the arrangement of secondary dust removal valves around the converter involved in the embodiment.

[0039] Figure 4 This is a logic diagram for controlling the opening degree of the secondary dust removal valve in the dry dust removal equipment involved in the embodiment. Detailed Implementation

[0040] Example

[0041] This embodiment describes a converter production method for online addition of converter dust recovery, taking the 250-ton converter of the No. 2 steelmaking plant at Meishan Steel Plant as an example. Figure 1 As shown, the system includes a dry dust removal device for use with a converter and an ash storage silo 1 for storing the dust recovered from the dry dust removal device. Additionally, an ash loading silo 2 is provided above the converter for directly storing the dust and has a first volumetric weight V1. In this embodiment, the first volumetric weight V1 of the ash loading silo 2 is 10 tons.

[0042] In the existing converter production process, the first bulk density V of dust to be added in the current converter production cycle is determined according to the production plan. Specifically, this involves obtaining converter production batch information, smelting process information, and received production instructions requiring the addition of dust to the converter, and then calculating the second bulk density V2 of dust to be added using an existing algorithm. The second bulk density V2 should satisfy a condition that is less than or equal to the first bulk density V1 and greater than or equal to the third bulk density V3, i.e., V3 ≤ V2 ≤ V1. In this embodiment, 3 ≤ V2 ≤ 9 tons.

[0043] The existing converter production process includes a first feeding step of adding scrap steel and molten iron to the converter before oxygen blowing, and a second feeding step of adding various auxiliary materials to the converter during oxygen blowing.

[0044] In the existing converter production process, the following additional steps are performed:

[0045] 1) After the converter production process begins,

[0046] The third bulk density V3 of the dust recovered by the dry dust removal equipment in the previous converter production process is measured, and the fourth bulk density V4 of the remaining dust in the ash bin is also measured.

[0047] If V3 + V4 < V1, proceed to the next step;

[0048] If V3+V4≥V1 or if the dry dust removal equipment malfunctions, then proceed to step 3).

[0049] In this embodiment, the amount of dust recovered by the dry dust removal equipment in each converter production is approximately 3 tons. Therefore, the third bulk density V3 of the dust measured in the previous converter production process is taken as 3 tons.

[0050] Taking actual production as an example, in the production process of a certain converter, the fourth bulk density V4 of the remaining dust in the metering and ash bin is 0.2 tons. Since V3 + V4 = 3.2 tons < 9 tons, step 2) below is executed.

[0051] Taking actual production as an example, in a certain converter production process, the fourth bulk density V4 of the remaining dust in the ash bin is 6.5 tons. Since V3 + V4 = 9.5 tons > 9 tons, step 3) below is executed.

[0052] 2) Before the first feeding step, the dust recovered by the dry dust removal equipment is fed into the ash hopper 2, and then the dust with a first bulk density V is added into the converter through the ash hopper 2.

[0053] In this embodiment,

[0054] If the calculated second volume V2 of the converter dust to be added is less than or equal to the sum of the third volume V3 and the fourth volume V4, such as V2 = 3 tons and V3 + V4 = 3.2 tons, then the dust is added to the converter in one batch.

[0055] If the calculated second volume V2 of the converter dust to be added is greater than the sum of the third volume V3 and the fourth volume V4 but less than twice the sum of the third volume V3 and the fourth volume V4, such as when V2 = 4 tons, (V3 + V4) * 2 = 6.4 tons, and 3.2 tons < 4 tons < 6.4, then the dust should be added to the converter in two batches with an interval of 25-35 seconds.

[0056] If the calculated second volume V2 of the converter dust to be added is greater than twice the sum of the third volume V3 and the fourth volume V4, i.e., V2 = 7 tons, then 7 tons > 6.4 tons, and the dust is added to the converter in three batches at intervals of 25-35 seconds.

[0057] Dust is added to the converter at a low fan speed. Since dust addition can affect the converter's production cycle, to avoid delays, the time interval between batches of dust addition is generally 25-35 seconds. Furthermore, a maximum of three batches of dust are added to each converter furnace cycle.

[0058] 3) First, the dust collected by the dry dust removal equipment is fed into the ash storage silo 1, and then the dust in the ash storage silo 1 is shaped into balls. Specifically, the dust in the ash storage silo 1 is output and sent to a special dust reprocessing workshop to be shaped into balls, and then the shaped dust is sent back to the high-level silo of the converter for adding auxiliary materials.

[0059] 4) In the second feeding step, the spherical dust is added to the converter together with the converter auxiliary materials.

[0060] In this embodiment, as Figure 2 As shown, the speed of the primary dust collector fan in a dry dust removal system is controlled according to the following conditions:

[0061] A. At the start of the converter production process, control the primary dust collector fan speed to 15-20% of its rated speed;

[0062] B. When adding the dust before the first feeding step, control the speed of the primary dust collector fan to 21-25% of its rated speed;

[0063] C. When adding scrap steel in the first feeding step, control the speed of the primary dust collector fan to 21-25% of its rated speed;

[0064] D. During the addition of molten iron in the first feeding step, the speed of the primary dust collector fan should be controlled at 75-80% of its rated speed;

[0065] E. In the second feeding step, the speed of the primary dust collector fan is controlled to be 100% of its rated speed.

[0066] In this embodiment, as Figure 3 As shown, a secondary dust removal valve is arranged around converter 3 on each of its east, west, and rear sides. These are designated as secondary dust removal valve FCV2 on the east side, FCV1 on the west side, and FCV3 on the rear side of the converter. Figure 4 As shown, the opening degree of the secondary dust removal valves in the dry dust removal equipment is controlled according to the following situations:

[0067] A. At the start of the converter production process, the opening degree of the secondary dust removal valve is controlled to be 15-20% of the maximum opening degree; in this embodiment, the opening degree is 20% of the maximum opening degree.

[0068] B. When adding dust before the first feeding step, the opening degree of the secondary dust removal valve is controlled to be 21-25% of the maximum opening degree of the secondary dust removal valve; in this embodiment, the opening degree is 20% of the maximum opening degree.

[0069] C. When adding scrap steel in the first feeding step, the opening degree of the secondary dust removal valve is controlled to be 75-80% of the maximum opening degree of the secondary dust removal valve; in this embodiment, the opening degree is 80% of the maximum opening degree.

[0070] D. When adding molten iron in the first feeding step, the opening degree of the secondary dust removal valve is controlled to be 81-85% of the maximum opening degree of the secondary dust removal valve; in this embodiment, the opening degree is 80% of the maximum opening degree.

[0071] E. In the second feeding step, the opening degree of the secondary dust removal valve is controlled to be 100% of the maximum opening degree of the secondary dust removal valve.

[0072] The above description is only a preferred embodiment of the present invention, but the present invention is not limited thereto. All equivalent substitutions or modifications made to the concepts and technical solutions of the present invention should be covered within the protection scope of the present invention.

Claims

1. A converter production method for online addition of converter recovered dust, wherein the converter is equipped with a dry dust removal device and an ash storage silo for storing the dust recovered by the dry dust removal device; an ash addition silo with a first bulk density V1 for directly storing the dust and a high-level silo for adding auxiliary materials for the converter are provided above the converter; In the converter production process, when the production plan determines that the dust needs to be added to the converter for that batch, the second bulk density V2 of the dust to be added in the current converter production process is determined according to the production plan; the converter production process includes a first feeding step of adding scrap steel and molten iron to the converter before oxygen blowing and a second feeding step of adding auxiliary materials to the converter during oxygen blowing; characterized in that: The following additional steps are performed in the converter production process: 1) After the converter production process begins, The third bulk density V3 of the dust recovered by the dry dust removal equipment in the previous converter production process is measured, and the fourth bulk density V4 of the remaining dust in the ash addition bin is measured. The second capacity V2 is less than or equal to the first capacity V1 and greater than or equal to the third capacity V3; If V3 + V4 < V1, proceed to the next step; If V3+V4≥V1 or if the dry dust removal equipment malfunctions, then proceed to step 3). 2) Before the first feeding step, the dust recovered by the dry dust removal equipment is first fed into the ash hopper, and then the dust with a first bulk density V is added into the converter through the ash hopper; 3) First, the dust collected by the dry dust removal equipment is fed into the ash storage bin, and then the dust in the ash storage bin is shaped into balls; 4) In the second feeding step, the dust, which is made into spherical shape, is added to the converter together with the auxiliary materials.

2. The converter production method for online addition of converter dust according to claim 1, characterized in that: In step 2), If the second capacity V2 is less than the sum of the third and fourth capacities V3 and V4, the dust is added to the converter in one batch. If the second capacity V2 is greater than the sum of the third capacity V3 and the fourth capacity V4 but less than twice the sum of the third capacity V3 and the fourth capacity V4, then the dust is added to the converter in two batches at an interval of 25-35 seconds. If the second capacity V2 is greater than twice the sum of the third and fourth capacities V3 and V4, the dust is added to the converter in three batches at intervals of 25-35 seconds.

3. The converter production method for online addition of converter dust according to claim 1, characterized in that: The speed of the primary dust collector fan in the dry dust removal equipment is controlled according to the following conditions: A. At the start of the converter production process, the speed of the primary dust collector fan is controlled to be 15-20% of its rated speed; B. When adding the dust before the first feeding step, the speed of the primary dust collector fan is controlled to be 21-25% of its rated speed; C. When adding scrap steel in the first feeding step, the speed of the primary dust collector fan is controlled to be 21-25% of its rated speed; D. During the addition of molten iron in the first feeding step, the speed of the primary dust collector fan is controlled to be 75-80% of its rated speed; E. In the second feeding step, the speed of the primary dust removal fan is controlled to be 100% of the rated speed.

4. The converter production method for online addition of converter dust recovery according to claim 1, characterized in that: The opening degree of the secondary dust removal valve of the dry dust removal equipment is controlled according to the following situations: A. At the start of the converter production process, the opening degree of the secondary dust removal valve is controlled to be 15-20% of its maximum opening degree; B. When adding the dust before the first feeding step, the opening degree of the secondary dust removal valve is controlled to be 21-25% of the maximum opening degree of the secondary dust removal valve; C. When adding scrap steel in the first feeding step, the opening degree of the secondary dust removal valve is controlled to be 75-80% of the maximum opening degree of the secondary dust removal valve; D. When adding molten iron in the first feeding step, the opening degree of the secondary dust removal valve is controlled to be 81-85% of the maximum opening degree of the secondary dust removal valve; E. In the second feeding step, the opening degree of the secondary dust removal valve is controlled to be 100% of the maximum opening degree of the secondary dust removal valve.

5. The converter production method for online addition of converter dust recovery according to claim 1, characterized in that: In step 3), the dust in the ash storage silo is output and sent to a special dust reprocessing workshop to be made into spheres, and then the spheres of dust are sent back to the high-level silo of the converter.

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