Smelting method based on blast furnace burden distribution system

Abstract

The invention belongs to the technical field of ferrous metallurgy, and relates to a smelting method based on a blast furnace burden distribution system, which comprises the following steps: adopting a burden distribution mode with the same batch weight; determining the batch weight of the blast furnace, wherein the batch weight comprises ore batch weight and coke batch weight; the ore batch weight is adjusted according to the coke batch weight, so that the gas flow temperature in the center of the coal gas meets a first set value; and adjusting the thickness ratio of the ore bed to the coke bed according to the distribution matrix to ensure the gas utilization rate. The method has the beneficial effects that a same ore batch distribution mode is adopted, and the smelting speed can be increased by increasing the batch weight; the reasonable coke batch weight is selected to ensure the coke window thickness, the ore batch weight is adjusted according to the coke batch weight, the gas flow temperature in the center of the gas is ensured, the secondary distribution of the gas flow in the furnace is optimized, and the gas utilization rate is improved, so that the purposes of reducing the fuel consumption and saving the cost are achieved; the thickness ratio of the ore bed to the coke layer is changed by adjusting the thickness of the coke layer at the furnace throat and the furnace bosh, and the coal gas utilization rate can be increased.

Description

Technical Field

[0001] The present invention belongs to the technical field of iron and steel metallurgy, and particularly relates to a smelting method based on the burden distribution system of a blast furnace. Background Art

[0002] The burden distribution system plays an important role in blast furnace smelting. It ensures the reasonable distribution of the coal gas flow in the upper lump zone, obtains a good shape of the cohesive zone, and improves the working state of the dropping zone. The size of the batch weight is the most important parameter in the burden distribution system of the blast furnace. A large ore batch can enable the blast furnace to obtain a thicker "coke window" under the condition of the same coke load, increase the gas permeability of the blast furnace, and also stabilize the blast furnace gas distribution, reduce the fluctuation of the coal gas flow, and improve the smelting speed.

[0003] However, with the increase in the batch weight, the thickness ratio of the ore layer to the coke layer also changes, significantly changing the development of the coal gas flow. The size of the batch weight directly affects the distribution of the coal gas flow, and the distribution of the coal gas flow in turn affects the utilization of the gas, restricting each other. The increase in the coal ratio will lead to poor gas permeability of the burden column, weaker central gas flow, and stronger edge gas flow. Although the increase in the batch weight is beneficial to suppressing the edge gas flow, at a large coal ratio, due to the significant increase in the ore-coke ratio, the coke window in the furnace becomes thinner, which is not conducive to the passage of the gas flow. Especially with the increase in the batch weight, the phenomenon becomes more serious, severely restricting the smelting speed. Therefore, a smelting method based on the burden distribution system of a blast furnace is needed to solve the above technical problems. Summary of the Invention

[0004] To solve the above existing technical problems, the present invention provides a smelting method based on the burden distribution system of a blast furnace, selects a reasonable ore batch weight and coke batch weight, gives priority to ensuring the temperature of the central gas flow of the gas, meets the requirements of the smooth operation of the blast furnace, and then adjusts the thickness ratio of the ore layer and the coke layer through the burden distribution matrix to improve the gas utilization rate.

[0005] The technical solution adopted in the embodiment of the present invention is: a smelting method based on the burden distribution system of a blast furnace, characterized in that it includes the following steps:

[0006] Adopt a burden distribution mode with the same batch weight;

[0007] Determine the batch weight of the blast furnace, and the batch weight includes the ore batch weight and the coke batch weight;

[0008] Adjust the ore batch weight according to the coke batch weight to make the temperature of the central gas flow of the gas meet the first set value;

[0009] Distribute the burden according to the burden distribution matrix, and adjust the thickness ratio of the ore layer and the coke layer to ensure that the gas utilization rate meets the second set value.

[0010] Further, the precondition for determining the coke batch weight is that when the secondary gas flow distribution of the gas is satisfied, the height of the coke window is 250 - 300 mm.

[0011] Further, the coke batch weight is Wc = pd 3 , where d is the diameter of the furnace throat and p is the coke batch coefficient.

[0012] Further, the ore batch weight is calculated according to the coke batch weight as Wt = (Wc / f) × 1000 / m, where f is the coke ratio / kg / t and m is the comprehensive in-furnace grade.

[0013] Further, the coke ratio f is 400 - 450 kg / t.

[0014] Further, the first set value is ≤500°C, and at the same time, the edge gas flow of the gas is ≤150°C.

[0015] Further, during batching, adjust the thickness of the coke layer at the furnace throat to be ≥485 mm and the thickness at the furnace belly to be ≥180 mm.

[0016] Further, during batching, according to the batch weight and the burden line, respectively adjust the first batching angle and the first batching number of turns of the coke layer, and the second batching angle and the second batching number of turns of the ore layer to ensure that the gas utilization rate meets the second set value.

[0017] Further, the second set value is ≥45%.

[0018] Further, during smelting, control the Si content to be 0.35% - 0.45%.

[0019] The advantages and positive effects of the present invention are as follows: adopting the batching mode with the same batch weight, increasing the batch weight can accelerate the smelting speed; selecting a reasonable coke batch weight to ensure the thickness of the coke window to improve the permeability of the burden; adjusting the ore batch weight according to the coke batch weight to ensure the temperature of the central gas flow of the gas, and at the same time optimizing the secondary distribution of the gas flow in the furnace to improve the gas utilization rate, so as to achieve the purpose of reducing fuel consumption and saving costs; by adjusting the thickness of the coke layer at the furnace throat and the furnace belly, and then changing the thickness ratio of the ore layer to the coke layer, it helps to improve the gas utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is the process flow during the use of the embodiment provided by the present invention;

[0021] Figure 2 is the simulation analysis result of Embodiment 1 in the embodiment provided by the present invention;

[0022] Figure 3 is the simulation analysis result of Embodiment 1 in the embodiment provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] An embodiment of the present invention provides a smelting method based on the burden distribution system of a blast furnace, which will be described below with reference to the accompanying drawings. Under normal circumstances, the reasonable ore batch weight should be less than 1 / 100 of the daily output. Generally, the ore batch weight is selected according to 0.80 - 0.95% of the daily output. The ore batch weight exceeding 1 / 100 of the daily output belongs to an oversized ore batch. This technical solution smelts based on an oversized ore batch, combines the batch weight and the burden distribution system, and realizes a good smelting effect.

[0024] Referring to Figure 1 As shown, a smelting method based on the burden distribution system of a blast furnace is characterized by including the following steps:

[0025] Adopt a burden distribution mode with the same batch weight;

[0026] Determine the batch weight of the blast furnace, where the batch weight includes the ore batch weight and the coke batch weight.

[0027] Adjust the ore batch weight according to the coke batch weight to make the temperature of the central gas flow of the blast furnace meet the first set value;

[0028] Distribute the burden according to the burden distribution matrix, and adjust the thickness ratio of the ore layer and the coke layer to ensure that the gas utilization rate meets the second set value.

[0029] The size of the batch weight plays a decisive role in the stability of the blast furnace gas flow and the quality of gas utilization. The superiority of increasing the batch weight is reflected in that it can stabilize the upper gas flow, increase the contact time between the gas and the burden, and improve gas utilization. At the same time, increasing the batch weight will reduce the number of layers of the entire burden column, reduce the interface effect, and also contribute to improving the permeability. However, if the batch weight is overly enlarged, it will increase the resistance of the central and peripheral gas flows of the blast furnace, cause gas imbalance, and as the batch weight increases, the blast furnace differential pressure will increase, resulting in phenomena such as a decrease in the air intake and heat absorption capacity of the blast furnace, affecting the smelting effect. In the technical solution of this application, a burden distribution mode with the same batch weight is selected. While increasing the batch weight, the burden distribution mode is adjusted and optimized. First, the temperature of the central gas flow of the blast furnace is stabilized to ensure the requirement of smooth operation. By adjusting the burden distribution matrix, the gas utilization rate is ensured, effectively ensuring the long-term stable and smooth operation of the furnace condition, realizing a steady increase in the gas utilization rate, an increase in the smelting intensity, and a gradual decrease in the fuel ratio, greatly reducing the ironmaking production cost.

[0030] Preferably, the precondition for determining the coke batch weight is that the height of the coke window is 250 - 300 mm when the secondary gas flow distribution of the blast furnace gas is satisfied. Almost all of the blast furnace gas passes through the "coke window" in the softening-melting zone. The coke batch weight largely determines the thickness of the coke layer, and the permeability of the softening-melting zone depends on the height of the softening-melting zone and the thickness of the "coke window". In order to control the height of the high-temperature zone of the blast furnace, the height of the softening-melting zone is restricted, and the thickness of the "coke window" is very important for improving the permeability of the overall burden column.

[0031] Preferably, the coke batch weight is Wc = pd 3, where d is the diameter of the furnace throat and p is the coke batch coefficient.

[0032] Preferably, the coke batch coefficient p is 0.029 - 0.032.

[0033] Preferably, the ore batch weight is calculated as Wt = (Wc / f) × 1000 / m according to the coke batch weight, where f is the coke ratio / kg / t and m is the comprehensive burden grade / %. The comprehensive burden grade here refers to the comprehensive burden grade of the iron-bearing materials, that is, the content of the useful components contained in the iron-bearing materials during the smelting process.

[0034] Preferably, the comprehensive burden grade m is 54 - 57.5%. The comprehensive burden grade m in Example 1 is 55.56%, and the comprehensive burden grade m in Example 2 is 54.5%.

[0035] Preferably, the coke ratio f is 350 - 400 kg / t. The coke ratio is one of the technical and economic indicators of blast furnace ironmaking, that is, the number of tons of coke consumed by the blast furnace for smelting one ton of qualified pig iron, which is a well-known technical indicator for those skilled in the art and will not be elaborated in depth here.

[0036] Preferably, the first set value is ≤ 500 °C, and at the same time, the gas edge flow is ≤ 150 °C. A reasonable gas flow distribution is the key to the smooth progress of ultra-large ore batch smelting. Ultra-large ore batch smelting has an inhibitory effect on both gas channels. Ensuring the smoothness of the center and the stability of the edge gas flow is the prerequisite for implementing ultra-large ore batch smelting. In this technical solution, while stabilizing the temperature of the gas center flow, taking into account the temperature of the edge gas flow is more conducive to improving the gas utilization rate.

[0037] Preferably, during charging, adjust the thickness of the coke layer at the furnace throat ≥ 485 mm and the thickness at the furnace belly ≥ 180 mm.

[0038] Preferably, during charging, according to the batch weight and the burden line, respectively adjust the first charging angle and the first number of charging circles of the coke layer, and the second charging angle and the second number of charging circles of the ore layer to ensure that the gas utilization rate meets the second set value. Setting a reasonable charging matrix and cooperating with the batch weight can not only ensure the gas center flow but also improve the gas utilization rate, achieving better energy conservation and emission reduction effects.

[0039] Preferably, the second set value is ≥ 45%. Before the burden in the blast furnace reaches the tuyere softening-melting zone, it always maintains the burden distribution state at the furnace throat and has obvious layers. There are obvious differences in the permeability indices between the ore layer and the coke layer. Where there is more coke, the development of the coal gas flow is easy; where there is less coke, the development of the coal gas flow is difficult. The change in the thickness ratio of the ore layer to the coke layer significantly changes the development of the coal gas flow, and the size of the ore batch weight directly affects the distribution of the coal gas flow, and the distribution of the coal gas flow in turn affects the utilization rate of the gas. In this technical solution, a reasonable coke batch weight is selected to ensure the thickness of the coke window, improve the burden permeability, stabilize the gas flow, adjust the ore batch weight according to the coke batch weight, ensure the temperature of the central gas flow in the gas, and at the same time optimize the secondary distribution of the coal gas flow in the furnace to improve the gas utilization rate, so as to achieve the purpose of reducing fuel consumption and saving costs.

[0040] Preferably, during smelting, the Si content is controlled at 0.35% - 0.45%, which helps to stabilize the furnace temperature and ensure sufficient heat in the hearth.

[0041] Preferably, during smelting, the titanium load is controlled at 10 - 13 kg / t. In this embodiment, adding a reasonable amount of titanium ore helps to maintain the safe and stable operation of the hearth. At the same time, the slag basicity is appropriately reduced in the control of the basicity to improve the fluidity of the slag.

[0042] Example 1:

[0043] The coke batch weight is 9000 kg, the ore batch weight is 45000 kg, the stock line is 1.5 m, and the comprehensive burden grade is 55.56%. Other parameters are shown in Table 1:

[0044] Table 1 The burden distribution matrix plan of Example 1

[0045]

[0046] From the burden distribution matrix, the burden angles of the coke layer and the ore layer are adjusted. The burden angles of the coke layer are 29° and 25° respectively, and the number of circles is 2, which is conducive to the development of the central gas flow, and the burden angles and the number of circles of the ore layer are adjusted accordingly.

[0047] According to the simulation results of the burden distribution matrix as Figure 2 shown, the burden surface distribution is in the shape of a platform funnel. The data of the burden layer distribution are shown in Table 2, and the corresponding blast furnace production indexes are shown in Table 3. The blast furnace coke load rises to 5.0, the fuel ratio decreases, the gas utilization rate rises to 45.8%, and all indexes of the blast furnace are good and the production is stable.

[0048] Table 2 The simulation results of Example 1

[0049] Item Value Item Value Item Value Width of coke platform m 1.49 Width of ore platform m 1.05 Ore-coke ratio O / C: Depth of coke hopper m 0.65 Depth of ore hopper m 0.92 Central average O / C 2.22 Inner stacking angle of coke ° 26.57 Inner stacking angle of ore ° 27.66 Intermediate average O / C 5.62 Outer stacking angle of coke ° 6.9 Outer stacking angle of ore ° 6.56 Average O / C of furnace wall 5.78 Thickness of inner coke layer m 0.77 Thickness of inner ore layer m 0.48 Thickness of outer coke layer m 0.49 Thickness of outer ore layer m 0.74

[0050] Table 3 The main production indexes of the blast furnace in Example 1

[0051]

[0052] Example 2:

[0053] Different from Example 1, in Example 2, the coke batch weight is adjusted to 8600 kg, the ore batch weight is adjusted to 43000 kg, and the comprehensive burden grade is 54.5%. Other parameters are shown in Table 4:

[0054] Table 4 Burden Distribution Matrix Scheme

[0055]

[0056] From the burden distribution matrix, the distribution angles of the coke layer and the ore layer are adjusted. The distribution angle of the coke layer is 23° and the number of circles is 2, which is beneficial to developing the central gas flow, and the distribution angle and the number of circles of the ore layer are adjusted accordingly.

[0057] The simulation results of the burden distribution matrix are as Figure 3 shown. The burden surface distribution is in the shape of a platform funnel. The data of the burden layer distribution are shown in Table 5, and the corresponding blast furnace production indexes are shown in Table 6. The coke load of the blast furnace remains 5.0, the fuel ratio increases slightly, the gas utilization rate is 45.5%, and all indexes of the blast furnace are good and the production is stable.

[0058] Table 5 Simulation Results of Example 2

[0059] Item Value Item Value Item Value Width of coke platform m 1.7 Width of ore platform m 1.19 Ore-coke ratio O / C: Depth of coke hopper m 0.53 Depth of ore hopper m 0.83 Central average O / C 2.36 Inner stacking angle of coke ° 25.8 Inner stacking angle of ore ° 27.42 Intermediate average O / C 5.56 Outer stacking angle of coke ° 4.86 Outer stacking angle of ore ° 6.34 Average O / C of furnace wall 5.32 Thickness of inner coke layer m 0.76 Thickness of inner ore layer m 0.45 Thickness of outer coke layer m 0.48 Thickness of outer ore layer m 0.69

[0060] Table 6 Main Production Indexes of the Blast Furnace in Example 1

[0061]

[0062] The advantages and positive effects of the present invention are as follows: adopting the burden distribution mode with the same batch weight, the increase of the batch weight can accelerate the smelting speed; selecting a reasonable coke batch weight to ensure the coke window thickness to improve the burden permeability, adjusting the ore batch weight according to the coke batch weight to ensure the central gas flow temperature of the gas, and at the same time optimizing the secondary distribution of the gas flow in the furnace to improve the gas utilization rate, so as to achieve the purpose of reducing fuel consumption and saving costs; by adjusting the thickness of the coke layer at the throat and belly of the furnace, and then changing the thickness ratio of the ore layer to the coke layer, it helps to improve the gas utilization rate.

[0063] The above has described the embodiments of the present invention in detail, but the above content is only the preferred embodiments of the present invention and cannot be considered as limiting the implementation scope of the present invention. All equivalent changes and improvements made according to the scope of the present invention application should still fall within the scope covered by the patent of the present invention.

Claims

1. A smelting method based on the burden distribution system of a blast furnace, characterized in that: It includes the following steps: Adopt a burden distribution mode with the same batch weight; Determine the batch weight of the blast furnace, and the batch weight includes the ore batch weight and the coke batch weight; Adjust the ore batch weight according to the coke batch weight to make the temperature of the central gas flow meet the first set value; Distribute the burden according to the burden distribution matrix, and adjust the thickness ratio of the ore layer and the coke layer to ensure that the gas utilization rate meets the second set value.

2. The smelting method based on the burden distribution system of a blast furnace according to claim 1, characterized in that: The premise for determining the coke batch weight is that when the secondary gas flow distribution is satisfied, the height of the coke window is 250 - 300 mm.

3. The smelting method based on the burden distribution system of a blast furnace according to claim 2, characterized in that: The coke batch weight is Wc = pd 3 , where d is the throat diameter of the furnace and p is the coke batch coefficient.

4. The smelting method based on the burden distribution system of a blast furnace according to claim 3, characterized in that: Calculate the ore batch weight according to the coke batch weight as Wt = (Wc / f) × 1000 / m, where f is the coke ratio / kg / t and m is the comprehensive in-furnace grade.

5. The smelting method based on the burden distribution system of a blast furnace according to claim 4, characterized in that: The coke ratio f is 350 - 400 kg / t.

6. The smelting method based on the burden distribution system of a blast furnace according to any one of claims 1 to 5, characterized in that: The first set value is ≤ 500 °C, and at the same time, the marginal gas flow of the gas is ≤ 150 °C.

7. The smelting method based on the burden distribution system of a blast furnace according to claim 6, characterized in that: During burden distribution, adjust the thickness of the coke layer at the throat of the furnace ≥ 485 mm and the thickness at the belly of the furnace ≥ 180 mm.

8. The smelting method based on the burden distribution system of a blast furnace according to any one of claims 1 to 5 and 7, characterized in that: During burden distribution, according to the batch weight and the burden line, respectively adjust the first burden distribution angle and the first number of burden distribution circles of the coke layer, and the second burden distribution angle and the second number of burden distribution circles of the ore layer to ensure that the gas utilization rate meets the second set value.

9. The smelting method based on the burden distribution system of a blast furnace according to claim 8, characterized in that: The second set value is ≥ 45%.

10. The smelting method based on the burden distribution system of a blast furnace according to any one of claims 1 to 5, 7, and 9, characterized in that: During smelting, control the Si content to be 0.35% - 0.45%.

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