Method for slowing down centralized erosion of annular belt on side wall of blast furnace hearth

Abstract

The invention relates to the technical field of smelting equipment, in particular to a method for slowing down concentrated erosion of an annular belt on the side wall of a blast furnace hearth, which comprises the following steps: 1) the upper surface of a blast furnace bottom brick lining is pot-bottom-shaped, and molten iron is gathered towards the middle of the furnace bottom; (2) adjusting the material of a hearth brick lining, wherein the compression strength, the slag corrosion resistance rate and the molten iron corrosion resistance index of a furnace bottom lining brick are required to be lower than those of a side wall annular belt lining brick; and 3) adjusting the furnace bottom cooling water amount according to the furnace bottom brick lining erosion degree in the blast furnace production process. The service life of the blast furnace can be effectively prolonged by changing the masonry structure of the blast furnace bottom, adjusting the material of the furnace lining, adjusting the cooling strength of the furnace bottom and reducing the concentrated erosion speed of the annular belt on the side wall of the hearth.

Description

Technical Field

[0001] The present invention relates to the technical field of smelting equipment, and particularly relates to a method for slowing down the concentrated erosion of the annular zone on the side wall of a blast furnace hearth. Background Art

[0002] The erosion morphology of the side wall of the blast furnace hearth is not uniform, but concentrated in the annular zone 1.5 to 2.0 meters below the taphole. The erosion rate of the brick lining in the annular zone can reach more than 80%. The erosion rate of the brick lining in the area outside the annular zone is less than 50%. The erosion rate of this annular zone becomes the determining factor for the life of the blast furnace and is the short board of the blast furnace life. There are mainly two reasons for this erosion morphology in the hearth. One is that the erosion rate of the bottom brick lining of the furnace is slow. When most blast furnaces are shut down, the erosion rate of the furnace bottom is less than 30%. As the furnace age increases, the height of the molten iron in the hearth changes little, and the molten iron circulation flows at the same height for a long time, resulting in a relatively fixed position where the side wall is scoured by the molten iron. The other is that the upper surface of the bottom brick lining of the furnace is flat. During the production process of the blast furnace, within the range of 100 mm to 200 mm from the upper edge of the furnace bottom, there is always a layer of molten or semi-molten molten iron stored. Since the molten iron in this state has little fluidity, during the tapping process of the blast furnace, the molten iron mainly accelerates the circulation along the side wall of the hearth, thus exacerbating the erosion of the side wall carbon bricks. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method for slowing down the concentrated erosion of the annular zone on the side wall of a blast furnace hearth, which can not only ensure the gradual downward movement of the molten iron circulation zone on the side wall of the hearth, but also prevent the excessive erosion of the bottom brick lining of the furnace from threatening the safety of the furnace bottom.

[0004] To achieve the above object, the present invention is realized by adopting the following technical solutions:

[0005] A method for slowing down the concentrated erosion of the annular zone on the side wall of a blast furnace hearth, comprising:

[0006] 1) The upper surface of the bottom brick lining of the blast furnace is in a pot-bottom shape, so that the molten iron gathers towards the middle of the furnace bottom;

[0007] 2) Adjust the material of the hearth brick lining, and require that the compressive strength, slag erosion resistance rate and iron melt erosion resistance index of the bottom lining brick are all lower than those of the side wall annular zone lining brick;

[0008] 3) During the production process of the blast furnace, adjust the cooling water volume of the furnace bottom according to the erosion degree of the bottom brick lining. The bottom brick lining from top to bottom is a ceramic pad and a full-laying carbon brick. Specifically:

[0009] ① When the furnace bottom ceramic pad exists and the full-laying carbon brick is not eroded, the cooling water volume of the furnace bottom is adjusted to 35%-50% of the maximum design flow rate;

[0010] ②All the ceramic pads at the furnace bottom are eroded. The residual thickness L of the full-laid carbon bricks is 1.8 - 2 m, including 1.8 m. The cooling water volume at the furnace bottom is 50% - 63% of the maximum designed flow rate;

[0011] ③All the ceramic pads at the furnace bottom are eroded. The residual thickness L of the full-laid carbon bricks is 1.6 - 1.8 m, including 1.6 m. The cooling water volume at the furnace bottom is 63% - 76% of the maximum designed flow rate;

[0012] ④All the ceramic pads at the furnace bottom are eroded. The residual thickness L of the full-laid carbon bricks is 1.4 - 1.6 m, including 1.4 m. The cooling water volume at the furnace bottom is 76% - 90% of the maximum designed flow rate;

[0013] ⑤All the ceramic pads at the furnace bottom are eroded. The residual thickness L of the full-laid carbon bricks is less than 1.4 m. The cooling water volume at the furnace bottom is the maximum designed flow rate.

[0014] In step 3), the full-laid carbon bricks include upper full-laid carbon bricks, middle full-laid carbon bricks and lower full-laid carbon bricks; the residual thickness L of the full-laid carbon bricks is calculated by the formula L = (1150 - T B )L 1 / (T B -T A )+L 2 ;

[0015] In the formula: T A is the central temperature of the upper surface of the lower full-laid carbon bricks, T B is the central temperature of the upper surface of the middle full-laid carbon bricks, L 1 is the distance between the temperature measurement points of T A and T B , and L 2 is the distance from the temperature measurement point to the lower surface of the lower full-laid carbon bricks. B

[0016] Compared with the existing technology, the beneficial effects of the present invention are:

[0017] 1. The furnace bottom is in a pot bottom shape, increasing the molten iron throughput at the furnace bottom and reducing the molten iron circulation on the side walls.

[0018] 2. Reducing the molten iron erosion resistance of the furnace bottom and appropriately accelerating the erosion rate of the furnace bottom. As the service time of the blast furnace extends, the thickness of the furnace bottom brick lining gradually thins, the molten iron height in the hearth gradually decreases, and the molten iron circulation position also decreases accordingly, slowing down the erosion rate of the original annular zone.

[0019] By changing the masonry structure of the blast furnace bottom, adjusting the lining material, and adjusting the cooling intensity of the furnace bottom, the present invention can slow down the concentrated erosion rate of the annular zone on the furnace hearth side wall and effectively extend the life of the blast furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is the masonry drawing of the blast furnace bottom. Specific Embodiments

[0021] The present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention. Additionally, it should be noted that, among the various specific technical features described in the above specific embodiments, they can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods. Furthermore, any combination can be made among various different embodiments of the present invention, as long as it does not violate the idea of the present invention, and it should also be regarded as the content disclosed by the present invention.

[0022] A method for slowing down the concentrated erosion of the annular zone on the sidewall of a blast furnace hearth, comprising:

[0023] 1) The upper surface of the bottom brick lining of the blast furnace is in a pot-bottom shape, causing the molten iron to gather towards the middle of the furnace bottom;

[0024] 2) Adjust the material of the hearth brick lining, and it is required that the compressive strength, slag erosion resistance rate, and iron water corrosion resistance index of the bottom lining brick are all lower than those of the sidewall annular zone lining brick;

[0025] The sidewall annular zone brick lining consists of a ceramic cup wall and a carbon brick wall from the inside to the outside. The performance of the lining brick of the ceramic cup wall: the normal temperature compressive strength ≥ 140 MPa, the slag erosion resistance rate ≤ 6%, and the iron water corrosion resistance index ≤ 1.5%. The performance of the lining brick of the carbon brick wall: the normal temperature compressive strength ≥ 50 MPa, the thermal conductivity ≥ 18 W / m·°C, and the iron water corrosion resistance index ≤ 10%.

[0026] The bottom brick lining of the furnace consists of a ceramic pad and a full-laid carbon brick from top to bottom. The performance of the lining brick of the ceramic pad: the normal temperature compressive strength ≥ 100 MPa, the slag erosion resistance rate ≤ 10%, and the iron water corrosion resistance index ≤ 3%. The performance of the lining brick of the full-laid carbon brick: the normal temperature compressive strength ≥ 40 MPa, the thermal conductivity ≥ 16 W / m·°C, and the iron water corrosion resistance index ≤ 28%.

[0027] 3) During the production process of the blast furnace, adjust the cooling water volume of the furnace bottom according to the erosion degree of the bottom brick lining, specifically:

[0028] ① When the bottom ceramic pad exists and the full-laid carbon brick is not eroded, the cooling water volume of the furnace bottom is adjusted to 35% - 50% of the maximum design flow rate;

[0029] ② When the bottom ceramic pad is completely eroded and the remaining thickness L of the full-laid carbon brick is 1.8 - 2 m, including 1.8 m, the cooling water volume of the furnace bottom is 50% - 63% of the maximum design flow rate;

[0030] ③All the ceramic pads at the furnace bottom are eroded. The remaining thickness L of the full-laid carbon bricks is 1.6 - 1.8 m, including 1.6 m. The cooling water volume at the furnace bottom is 63% - 76% of the maximum designed flow rate.

[0031] ④All the ceramic pads at the furnace bottom are eroded. The remaining thickness L of the full-laid carbon bricks is 1.4 - 1.6 m, including 1.4 m. The cooling water volume at the furnace bottom is 76% - 90% of the maximum designed flow rate.

[0032] ⑤All the ceramic pads at the furnace bottom are eroded. The remaining thickness L of the full-laid carbon bricks is less than 1.4 m. The cooling water volume at the furnace bottom is the maximum designed flow rate.

[0033] In step 3), the full-laid carbon bricks include upper full-laid carbon bricks, middle full-laid carbon bricks and lower full-laid carbon bricks; the remaining thickness L of the full-laid carbon bricks is calculated by the formula L = (1150 - T B )L 1 / (T B -T A )+L 2 ;

[0034] In the formula: T A is the central temperature of the upper surface of the lower full-laid carbon bricks, T B is the central temperature of the upper surface of the middle full-laid carbon bricks, L 1 is the distance between the temperature measurement point of T A and the temperature measurement point of T B , and L 2 is the distance from the temperature measurement point of T B to the lower surface of the lower full-laid carbon bricks.

[0035] To make the objectives, technical solutions and technical effects of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. However, the embodiments described below are only a part of the embodiments of the present invention, rather than all of the embodiments. Combining the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention.

[0036] Example 1:

[0037] The effective volume of No. 10 blast furnace in a certain steel plant is 3200 m 3 , and the hearth diameter is 12.33 m. The thickness of the ceramic pad at the furnace bottom is 0.8 m, the total thickness of the full-laid carbon bricks is 2 m, and the maximum designed value of the cooling water volume at the furnace bottom is 600 m 3 / h.

[0038] A method for slowing down the concentrated erosion of the circumferential zone on the side wall of the blast furnace hearth includes:

[0039] 1) The upper surface of the brick lining at the blast furnace bottom is in a pot-bottom shape, so that the molten iron gathers towards the middle of the furnace bottom;

[0040] 2) Adjust the material of the hearths lining bricks, and require that the compressive strength, slag erosion resistance rate, and molten iron corrosion resistance index of the hearths bottom lining bricks are all lower than those of the sidewall annular zone lining bricks;

[0041] The sidewall annular zone brick lining consists of a ceramic cup wall and a carbon brick wall from the inside to the outside;

[0042] The lining bricks of the ceramic cup wall adopt microporous corundum mullite, with a normal temperature compressive strength ≥ 140 MPa, a slag erosion resistance rate ≤ 6%, and a molten iron corrosion resistance index ≤ 1.5%.

[0043] The lining bricks of the carbon brick wall adopt ultra-microporous carbon bricks, with a normal temperature compressive strength ≥ 50 MPa, a thermal conductivity coefficient ≥ 18 W / m·°C, and a molten iron corrosion resistance index ≤ 10%.

[0044] The hearths bottom brick lining consists of a ceramic pad and a fully paved carbon brick from top to bottom;

[0045] The performance of the lining bricks of the ceramic pad adopts corundum mullite, with a normal temperature compressive strength ≥ 100 MPa, a slag erosion resistance rate ≤ 10%, and a molten iron corrosion resistance index ≤ 3%.

[0046] The fully paved carbon brick includes an upper layer fully paved carbon brick, a middle layer fully paved carbon brick, and a lower layer fully paved carbon brick; the upper layer fully paved carbon brick and the middle layer fully paved carbon brick adopt microporous carbon bricks, and the lower layer fully paved carbon brick adopts graphite carbon bricks, with a normal temperature compressive strength ≥ 40 MPa, a thermal conductivity coefficient ≥ 16 W / m·°C, and a molten iron corrosion resistance index ≤ 28%.

[0047] 3) During the blast furnace production process, adjust the cooling water volume of the hearths bottom according to the erosion degree of the hearths bottom brick lining. The remaining thickness L of the fully paved carbon brick is calculated by the formula L = (1150 - T B )L 1 / (T B -T A )+L 2 ;

[0048] In the formula: T A is the center temperature of the upper surface of the lower layer fully paved carbon brick, T B is the center temperature of the upper surface of the middle layer fully paved carbon brick, L 1 is the distance between the temperature measurement point of T A and the temperature measurement point of T B , and L 2 is the distance from the temperature measurement point of T B to the lower surface of the lower layer fully paved carbon brick.

[0049] For No. 10 blast furnace, the distance L A between the temperature measurement point of T B and the temperature measurement point of T 1 is 0.6 m, and the distance L B from the temperature measurement point of T 2 to the lower surface of the lower layer fully paved carbon brick is 1.0 m. T A and TB The temperature value varies with the blast furnace production.

[0050] Bottom cooling capacity adjustment plan:

[0051] ① The bottom ceramic pad exists, the full - laid carbon bricks are not eroded, and the bottom cooling water volume is 230 - 300 m 3 / h (the minimum adjustable bottom cooling water volume of the blast furnace can be adjusted to 230 m 3 / h);

[0052] ② The bottom ceramic pad is completely eroded, the remaining thickness L of the full - laid carbon bricks is 1.8 - 2 m, including 1.8 m, and the bottom cooling water volume is 300 - 380 m 3 / h;

[0053] ③ The bottom ceramic pad is completely eroded, the remaining thickness L of the full - laid carbon bricks is 1.6 - 1.8 m, including 1.6 m, and the bottom cooling water volume is 380 - 460 m 3 / h;

[0054] ④ The bottom ceramic pad is completely eroded, the remaining thickness L of the full - laid carbon bricks is 1.4 - 1.6 m, including 1.4 m, and the bottom cooling water volume is 460 - 540 m 3 / h;

[0055] ⑤ The bottom ceramic pad is completely eroded, the remaining thickness L of the full - laid carbon bricks is < 1.4 m, and the bottom cooling water volume is 600 m 3 / h.

[0056] Example 2:

[0057] The effective volume of the No. 4 blast furnace in a certain steel plant is 2580 m 3 , and the hearth diameter is 11.5 m. The thickness of the bottom ceramic pad is 0.8 m, the total thickness of the full - laid carbon bricks is 2 m, and the designed maximum bottom cooling water volume is 500 m 3 / h.

[0058] A method for slowing down the concentrated erosion of the circumferential zone on the side wall of the blast furnace hearth, including:

[0059] 1) The upper surface of the bottom brick lining of the blast furnace is in a pot - bottom shape, so that the molten iron gathers towards the middle of the furnace bottom;

[0060] 2) Adjust the material of the hearth brick lining, and require that the compressive strength, slag erosion resistance rate and molten iron corrosion resistance index of the bottom lining bricks are all lower than those of the circumferential zone lining bricks on the side wall;

[0061] The circumferential zone brick lining on the side wall consists of a ceramic cup wall and a carbon brick wall from the inside to the outside;

[0062] The lining bricks of the ceramic cup wall are made of microporous corundum - mullite, with a normal - temperature compressive strength ≥ 140 MPa, a slag erosion resistance rate ≤ 6%, and a molten iron corrosion resistance index ≤ 1.5%.

[0063] The lining bricks of the carbon brick wall are made of ultra-microporous carbon bricks, with a cold compressive strength of ≥50 MPa, a thermal conductivity of ≥18 W / m·°C, and an iron water corrosion index of ≤10%.

[0064] The bottom lining of the furnace consists of a ceramic pad and full-laying carbon bricks from top to bottom;

[0065] The lining bricks of the ceramic pad are made of corundum-mullite, with a cold compressive strength of ≥100 MPa, a slag erosion resistance rate of ≤10%, and an iron water corrosion resistance index of ≤3%.

[0066] The full-laying carbon bricks include upper full-laying carbon bricks, middle full-laying carbon bricks, and lower full-laying carbon bricks; the upper full-laying carbon bricks and middle full-laying carbon bricks are made of microporous carbon bricks, and the lower full-laying carbon bricks are made of graphite carbon bricks, with a cold compressive strength of ≥40 MPa, a thermal conductivity of ≥16 W / m·°C, and an iron water corrosion index of ≤28%.

[0067] 3) During the blast furnace production process, according to the erosion degree of the bottom lining of the furnace, adjust the cooling water volume at the bottom of the furnace. The remaining thickness L of the full-laying carbon bricks is calculated by the formula L = (1150 - T B )L 1 / (T B -T A )+L 2 ;

[0068] In the formula: T A is the center temperature of the upper surface of the lower full-laying carbon bricks, T B is the center temperature of the upper surface of the middle full-laying carbon bricks, L 1 is the distance between the temperature measurement point of T A and the temperature measurement point of T B , and L 2 is the distance from the temperature measurement point of T B to the lower surface of the lower full-laying carbon bricks.

[0069] For No. 4 blast furnace, the distance L A between the temperature measurement point of T B and the temperature measurement point of T 1 is 0.5 m, and the distance L B from the temperature measurement point of T 2 to the lower surface of the lower full-laying carbon bricks is 1.0 m. The temperature values of T A and T B vary with the blast furnace production.

[0070] Bottom furnace cooling volume adjustment plan:

[0071] ① When the ceramic pad exists and the full-laying carbon bricks are not eroded, the bottom furnace cooling water volume is 200 - 250 m 3 / h; (the minimum adjustable bottom furnace cooling water volume of the blast furnace can be adjusted to 200 m 3 / h);

[0072] ②All the ceramic pads at the furnace bottom are eroded. The remaining thickness L of the full-laid carbon bricks is 1.8 - 2 m, including 1.8 m. The cooling water volume at the furnace bottom is 250 - 310 m 3 / h;

[0073] ③All the ceramic pads at the furnace bottom are eroded. The remaining thickness L of the full-laid carbon bricks is 1.6 - 1.8 m, including 1.6 m. The cooling water volume at the furnace bottom is 310 - 380 m 3 / h;

[0074] ④All the ceramic pads at the furnace bottom are eroded. The remaining thickness L of the full-laid carbon bricks is 1.4 - 1.6 m, including 1.4 m. The cooling water volume at the furnace bottom is 380 - 450 m 3 / h;

[0075] ⑤All the ceramic pads at the furnace bottom are eroded. The remaining thickness L of the full-laid carbon bricks is < 1.4 m. The cooling water volume at the furnace bottom is 500 m 3 / h.

[0076] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and basic spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for slowing down the concentrated erosion of the annular zone of the side wall of a blast furnace, characterized in that: include: 1) The upper surface of the blast furnace bottom brick lining is pot-bottom shaped, so that the molten iron gathers in the middle of the furnace bottom; 2) Adjust the material of the furnace brick lining, requiring the compressive strength, slag erosion resistance and iron water dissolution resistance of the furnace bottom lining brick to be lower than that of the side wall annular belt lining brick; 3) During the blast furnace production process, the amount of cooling water at the bottom of the furnace is adjusted according to the degree of erosion of the furnace bottom brick lining. The furnace bottom brick lining is ceramic pads and full carbon bricks from top to bottom, specifically: ① The ceramic pad at the bottom of the furnace is in place, the carbon bricks are fully covered and not corroded, and the cooling water volume at the bottom of the furnace is adjusted to 35%-50% of the maximum design flow rate; ② The ceramic pad at the bottom of the furnace is completely eroded, the residual thickness of the fully paved carbon bricks is L 1.8-2m, including 1.8m, and the cooling water volume at the bottom of the furnace is 50%-63% of the maximum design flow; ③ The ceramic pad at the bottom of the furnace is completely eroded, the residual thickness L of the fully paved carbon bricks is 1.6-1.8m, including 1.6m, and the cooling water volume at the bottom of the furnace is 63%-76% of the maximum design flow; ④ The ceramic pad at the bottom of the furnace is completely eroded, the residual thickness L of the fully paved carbon bricks is 1.4-1.6m, including 1.4m, and the cooling water volume at the bottom of the furnace is 76%-90% of the maximum design flow; ⑤ The ceramic pad at the bottom of the furnace is completely eroded, the residual thickness of the fully covered carbon bricks L is less than 1.4m, and the cooling water volume at the bottom of the furnace is the maximum design flow rate.

2. The method for alleviating concentrated erosion of the annular zone on the side wall of a blast furnace according to claim 1, characterized in that: Step 3) The full carbon bricks include the upper layer, the middle layer and the lower layer. The residual thickness L of the full carbon bricks is given by the formula L = (1150-T B )L1 / (T B -T A )+L2 is calculated; Where: T A is the center temperature of the upper surface of the lower layer of fully paved carbon bricks, T B is the center temperature of the upper surface of the middle layer of fully paved carbon bricks, L1 is T A Temperature measurement point and T B The distance between the temperature measurement points, L2 is T B The distance between the temperature measuring point and the lower surface of the lower layer of fully paved carbon bricks.

Images