Method for determining first tapping time after blast furnace inspection and blowing

Abstract

The application discloses a method for determining the first tapping time after blast furnace inspection and blowing, and considers the relationship among the air volume after blast furnace inspection and blowing, the slag-iron generating volume, the porosity of the blast furnace hearth and the safe slag-iron storage volume of the blast furnace, deduces the method and the calculation formula for calculating the slag-iron generating volume from the air volume after the blast furnace inspection and blowing, establishes the regression equation between the accumulated air volume and the accumulated slag-iron generating volume under different blast furnace blowing materials, and determines the accumulated air volume when the first tapping is performed after the blowing by the safe slag-iron storage volume of the blast furnace and the regression equation. Finally, the first tapping time after the blast furnace inspection and blowing is determined by the accumulated air volume. The application can reasonably determine the tapping time after the blowing, sufficiently heats the blast furnace hearth under the safe condition, reduces the working strength of the blast furnace front, and is beneficial to the smooth recovery of the blast furnace after the blast furnace inspection and blowing.

Description

Technical Field

[0001] This invention relates to the field of iron and steel metallurgy, and more particularly to a method for determining the time of the first taphole opening after the blast furnace is scheduled for maintenance. Background Technology

[0002] The timing of the first taphole opening after blast furnace maintenance and blast supply is crucial. Opening the taphole too early results in insufficient slag and iron production, leading to severe taphole splashing. Furthermore, the limited slag and iron production means insufficient heating time in the hearth, resulting in poor slag and iron flowability and separation. This not only increases the risk of iron contamination in the slag but also causes accumulation in the main trough, iron trough, and slag trough, increasing the workload in front of the furnace. Conversely, opening the taphole too late results in excessive slag and iron production, leading to a higher liquid level in the hearth and increased blast pressure. This negatively impacts the safe operation of the tuyeres and hinders blast furnace blast supply recovery. Therefore, only by rationally determining the timing of the first taphole opening after blast furnace maintenance and blast supply can a smooth blast furnace blast supply recovery be effectively ensured.

[0003] The existing method for determining the timing of the first taphole opening is based on the blast time, blast volume, and batch size of the charge. Taphole opening is organized only after these conditions are met. The drawback of this method is that it fails to consider the discrepancy between the amount of slag and iron charged at the furnace top and the amount generated in the hearth region, and it does not quantify the relationship between blast parameters and the slag and iron level in the hearth. To ensure blast safety, the time determined by traditional methods for the first taphole opening is often too early. Therefore, how to more accurately, conveniently, and stably determine the timing of the first taphole opening after blast furnace maintenance is a problem that urgently needs to be solved by those skilled in the art.

[0004] The purpose of this invention is to provide a method for determining the appropriate time for opening the taphole during the initial blast furnace maintenance. This method can determine the appropriate taphole opening time while ensuring the safety of the blast furnace tuyeres and the smooth operation of the blast furnace. It can also ensure sufficient heating of the hearth while reducing the intensity of front-of-furnace operations, and provide a basis for adjusting the blast furnace maintenance and production organization after the blast furnace maintenance. Summary of the Invention

[0005] The purpose of this invention is to address the above-mentioned problems by providing a method for determining the time of the first taphole opening after the blast furnace is scheduled for maintenance.

[0006] The objective of this invention is achieved as follows: A method for determining the first taphole opening time after blast furnace scheduled maintenance includes the following steps: Step 1: Collect the number of batches of furnace charge, batch iron quantity, slag ratio, coke ratio, coal ratio, and fixed carbon content of coke and pulverized coal for each section of the blast furnace hearth, belly, waist, body, and throat during the scheduled maintenance shutdown. Obtain the volume from the taphole centerline to the lower edge of the tuyeres in the hearth region based on the blast furnace dimensions. Step 2: Calculate the fuel ratio and carbon ratio of the furnace charge for each section of the blast furnace based on the coke ratio, coal ratio, and fixed carbon content of coke and pulverized coal.

[0007] C 碳比i =C coke × CR i +C Coal Powder × PCR i

[0008] FR i =CR i +PCR i

[0009] i: represents a section of the hearth, belly, waist, body, or throat.

[0010] C 碳比i Iron-to-carbon ratio per ton (kg / t)

[0011] C 焦炭i Effective fixed carbon content of coke, in %

[0012] C 煤粉i Effective fixed carbon content of pulverized coal, in %

[0013] FR i Fuel ratio to furnace, unit kg / t

[0014] CR i : The ratio of iron to coke per ton of feed material during rest periods, in kg / t.

[0015] PCR i : Fuel-to-iron ratio per tonne of blast furnace feed, unit: kg / t; Step 3: Carbon content of molten iron under different fuel ratios [C] i The corresponding carbon content of molten iron is 36-47 kg. The relationship between [C] and fuel ratio is as follows: Fuel ratio, kg: <550, [C], kg: 47; Fuel ratio, kg: 550≤X<600, [C], kg: 45; Fuel ratio, kg: 600≤X<800, [C], kg: 43; Fuel ratio, kg: 800≤X<1500, [C], kg: 40; Fuel ratio, kg: ≥1500, [C], kg: 36; X represents the fuel ratio per ton of iron; Step 4: Determine the blast volume per ton of iron consumed in each section of the blast furnace (hearth, belly, waist, body, and throat) based on the carbon ratio per ton of iron and the carbon content of molten iron.

[0016] BV耗风i =(C 碳比i -[C] i -130)×4.44

[0017] BV 耗风i Air consumption per ton of iron in each section of the blast furnace, in m³. 3 / t,

[0018] C 碳比i Iron-to-carbon ratio per ton (kg / t)

[0019] [C] i : Carbon content of molten iron in each section of the blast furnace hearth, belly, waist, body, and throat, in kg / t; Step 5: Calculate the air consumption per batch and the slag and iron generation volume per batch in each section of the blast furnace based on the slag ratio and batch iron quantity. Then, starting from the hearth towards the throat, calculate the cumulative air consumption and cumulative slag and iron generation volume up to the Nth batch, where N is the number of batches charged during scheduled maintenance and downtime. In the calculation formula, 6.7 represents the specific gravity of molten iron, and 2 represents the specific gravity of slag.

[0020] BV 批料耗风i =BV 耗风i ×M i

[0021] BV 累计耗风i =BV 批料耗风i ×CH i

[0022] V 批料i =M i ÷6.7+M i ×SCR i ÷2

[0023] BV 累计耗风 =ΣBV 批料耗风i

[0024] V 累计 =ΣV 批料i

[0025] BV 批料耗风i The air consumption of each section of the blast furnace during the smelting of a batch, in cubic meters. 3 ,

[0026] M i Iron content of each batch of material in each section of the blast furnace, in tons per batch.

[0027] BV 累计耗风i Cumulative air consumption in each section of the blast furnace, in cubic meters. 3 ,

[0028] CH i Number of material batches and unit batch for each section of the blast furnace.

[0029] V批料i The volume of slag and iron produced by smelting a batch of materials in each section of the blast furnace.

[0030] SCR i Slag ratio of each section of the furnace, in tons (t / t).

[0031] BV 累计耗风 : Cumulative air volume consumed during smelting up to the Nth batch, in m³ 3 ,

[0032] V 累计 : The cumulative slag and iron volume generated when smelting up to the Nth batch, in m³ 3 Step Six: The cumulative air consumption equation can be derived from the cumulative slag and iron production volume when smelting up to the Nth batch, as shown below:

[0033] Cumulative air consumption regression equation: y = ax 3 +bx 2 +cx+d

[0034] y: Cumulative air volume, in meters (m³) 3 x: Volume of slag and iron produced, in meters (m). 3 a, b, c, and d are constants, which vary depending on the blast furnace maintenance load; Step 7: Determine the maximum safe slag iron storage volume based on the volume from the centerline of the blast furnace taphole to the lower edge of the tuyeres and the hearth porosity. In the calculation formula, 0.5 is the safety factor and 0.25 is the hearth porosity.

[0035] V 最大安全储渣铁体积 =V1×0.5×0.25

[0036] V 最大安全储渣铁体积 Maximum safe slag storage volume, in cubic meters (m³). 3 ,

[0037] V1: Volume from the centerline of the taphole to the lower edge of the tuyeres; Step 8: The safe slag and iron storage volume is used as the cumulative slag and iron generation volume, and substituted into the cumulative air consumption regression equation: y = ax 3 +bx 2 The cumulative air consumption BV when the slag and iron production reaches the safe slag and iron storage volume is calculated using +cx+d. 安全储渣铁累计耗风 .

[0038] Steps one through eight determine the cumulative air volume after the blast furnace scheduled maintenance, which reaches BV. 安全储渣铁累计耗风 This was the first time the iron ore was opened.

[0039] The beneficial effects of this invention are: it quantifies the relationship between the cumulative air volume fed into the furnace and the volume of slag and iron generated, and, in conjunction with the maximum safe slag and iron storage volume of the blast furnace, rationally determines the time for the first taphole opening after the blast furnace is blasted during scheduled maintenance, thereby achieving full heating of the hearth under safe conditions, reducing the workload of the furnace front-end during scheduled maintenance blasting, and also facilitating the smooth recovery of the blast furnace after scheduled maintenance blasting. Attached Figure Description

[0040] The present invention will now be further described with reference to the accompanying drawings.

[0041] Figure 1 This is a schematic diagram of the method of the present invention.

[0042] Figure 2 It is a scatter plot of the regression equation between the cumulative slag and iron generation volume and the cumulative air consumption.

[0043] Figure 3 This is a schematic diagram of the blast furnace structure.

[0044] Among them: 1. Material line L, 2. H 炉喉 3.D 炉喉 4.H 炉身 5.D X1 6.D 炉腰 7.H 炉腹 8.D X2 9.D 炉缸 10. Furnace throat diameter, 11. Furnace body diameter at any point, 12. Furnace waist diameter, 13. Tubular center diameter, 14. Taphole center diameter. Detailed Implementation

[0045] The amount of slag and iron generated after the blast furnace scheduled maintenance and the slag and iron liquid level in the hearth are important bases for determining the taphole opening time after blast furnace maintenance. The traditional method judges the amount of slag and iron generated based on the top charge. However, because the top charge is unstable in the early stage of blast furnace maintenance and the amount of slag and iron charged into the furnace top is inconsistent with the amount of slag and iron generated in the hearth area, the amount of slag and iron generated based on the top charge is inaccurate. As a result, the taphole opening time determined by this method is also prone to large deviations. For safety reasons, the first taphole opening time determined by the traditional method is often too early, which increases the workload in front of the furnace and has a negative impact on the blast furnace blast furnace recovery operation and production organization.

[0046] This invention provides a method for determining the time of the first taphole opening after blast furnace scheduled maintenance. By studying the relationship between blast parameters, rest load, hearth porosity, and slag-iron level after blast furnace scheduled maintenance, a method and calculation formula for determining the time of the first taphole opening after blast furnace scheduled maintenance are derived. After comparing the model calculations with actual data of the first taphole opening after blast furnace scheduled maintenance in the past, relevant correction data are obtained. Using data analysis methods and actual data after scheduled maintenance, the coefficient constants in the calculation method are corrected, and finally, the calculation method and calculation formula for the time of the first taphole opening after blast furnace scheduled maintenance are determined.

[0047] This invention studies the relationship between blast furnace blasting parameters, rest load, hearth porosity, slag and iron production, and hearth slag and iron liquid level. It determines the amount of oxygen consumed, slag production, and production volume required to produce one ton of iron under different load levels. It also obtains a regression equation between cumulative blasting consumption and cumulative slag and iron production volume. Finally, it determines the cumulative blasting volume at the first taphole opening after blasting is determined by the safe slag and iron storage volume. The reasonable time for the first taphole opening after scheduled maintenance is then determined by the cumulative blasting volume.

[0048] The specific contents of this invention are as follows: 1. Collect data on the number of batches of furnace charge, batch iron quantity, slag ratio, coke ratio, coal ratio, and fixed carbon content of coke and pulverized coal for each section of the blast furnace hearth (above the tuyere), belly, waist, body, and throat during blast furnace maintenance and shutdown. Calculate the volume from the centerline of the taphole to the lower edge of the tuyere sleeve in the hearth region based on the blast furnace dimensions. A blast furnace is generally divided into five sections: throat, body, belly, waist, and hearth. The throat, waist, and hearth are cylindrical structures, while the body and belly are frustum structures. The height and diameter of each section, including data on the centerline of the taphole and the lower edge of the tuyere sleeve, are collected. Both the taphole and tuyere are located in the hearth, as shown in the figure below. Based on the designed furnace shape, the height and diameter of each section can be obtained. The volume from the centerline of the taphole to the lower edge of the tuyere sleeve can be calculated from the blast furnace dimensions.

[0049] 2. The iron-to-coke ratio, coal ratio, and fixed carbon content of coke and pulverized coal in each section of the blast furnace are calculated from the data on the iron-to-coke ratio, coal ratio, and fixed carbon content of coke and pulverized coal in each section of the blast furnace: C 碳比i =C coke × CR i +C Coal Powder × PCR i FR i =CR i +PCR i .

[0050] i: represents a section of the hearth, belly, waist, body, or throat; C 碳比i Iron-to-carbon ratio per ton (kg / t), C 焦炭i Effective fixed carbon content of coke, in % (C) 煤粉i Effective fixed carbon content of pulverized coal, in % FR i Fuel ratio fed into the furnace, unit kg / t, CRi : Ratio of iron to coke per ton of feedstock during downtime, unit: kg / t, PCR i : The ratio of iron to coal per ton of furnace feed material during downtime, in kg / t.

[0051] 3. The carbon content [C] of molten iron under different fuel ratios was obtained through big data analysis and regression methods. i The corresponding carbon content of molten iron is 36-47 kg. The relationship between [C] and fuel ratio is shown in the table below.

[0052] Table 1. Carbon content of molten iron corresponding to different fuel ratios, unit: kg / t

[0053] [C], kg 47 45 43 40 36

[0054] Note: X represents the fuel ratio per ton of iron.

[0055] [C] i Carbon content of molten iron in the hearth (above the tuyere), belly, waist, body and throat of the blast furnace, in kg / t.

[0056] 4. Determine the blast volume per ton of iron consumed in each section of the blast furnace, including the hearth (above the tuyere), belly, waist, body, and throat, based on the carbon ratio per ton of iron and the carbon content of the molten iron.

[0057] BV 耗风i =(C 碳比i -[C] i -130)×4.44, BV 耗风i Air consumption per ton of iron in each section of the blast furnace, in m³. 3 / t.

[0058] 5. Calculate the air consumption per batch and the slag-iron volume per batch during the smelting process based on the slag ratio and batch iron quantity in each section of the blast furnace. Then, starting from the hearth (above the tuyere centerline) towards the furnace throat, calculate the cumulative air consumption and cumulative slag-iron volume up to the Nth batch. N is the number of batches charged during scheduled maintenance shutdowns. In the calculation formula, 6.7 represents the specific gravity of molten iron, and 2 represents the specific gravity of slag. BV 批料耗风i =BV 耗风i ×M i BV 累计耗风i =BV 批料耗风i ×CH i V 批料i =M i ÷6.7+M i ×SCR i ÷2, BV 累计耗风 =ΣBV 批料耗风i V 累计 =ΣV 批料i .

[0059] BV 批料耗风iThe air consumption of each section of the blast furnace during the smelting of a batch, in cubic meters. 3 M i Iron content of each batch of material in each section of the blast furnace, in tons per batch (BV). 累计耗风i Cumulative air consumption in each section of the blast furnace, in cubic meters. 3 CH i Number of material batches in each section of the blast furnace, unit batch, V 批料i : The volume of slag and iron generated by smelting a batch of feed in each section of the blast furnace, SCR i Slag ratio of each section of the furnace, in tons (t / t), BV 累计耗风 : Cumulative air volume consumed during smelting up to the Nth batch, in m³ 3 V 累计 : The cumulative slag and iron volume generated when smelting up to the Nth batch, in m³ 3 .

[0060] 6. The cumulative air consumption and the corresponding cumulative slag and iron production volume from smelting to the Nth batch can be used to regress the cumulative air consumption equation, as shown below: Cumulative air consumption regression equation: y = ax 3 +bx 2 +cx+d.

[0061] y: Cumulative air volume, in meters (m³) 3 x: Volume of slag and iron produced, in meters (m³) 3 a, b, c, and d are constants, which vary depending on the blast furnace's maintenance and downtime load. (A cubic regression equation is obtained by plotting the cumulative blast volume and cumulative slag and iron production volume. a, b, and c are the coefficients of the regression equation. When the load is different, the blast consumption per ton of iron is different, and the regression coefficients will be different.)

[0062] 7. The maximum safe slag iron storage volume is determined by the volume from the centerline of the blast furnace taphole to the lower edge of the tuyeres and the hearth porosity. In the calculation formula, 0.5 is the safety factor and 0.25 is the hearth porosity. V 最大安全储渣铁体积 =V1×0.5×0.25, V 最大安全储渣铁体积 Maximum safe slag storage volume, in cubic meters (m³). 3 .

[0063] V1: The volume from the centerline of the iron taphole to the lower edge of the vent sleeve.

[0064] 8. The safe slag and iron storage volume is used as the cumulative slag and iron generation volume, and substituted into the cumulative air consumption regression equation: y = ax 3 +bx 2 The cumulative air consumption BV when the slag and iron production reaches the safe slag and iron storage volume is calculated using +cx+d. 安全储渣铁累计耗风 .

[0065] 9. From 1-8, it can be determined that the cumulative air volume after the blast furnace scheduled maintenance reaches BV. 安全储渣铁累计耗风This was the first time the iron ore was opened.

[0066] The specific embodiments of the present invention will be further illustrated below, but the specific embodiments of the present invention are not limited to the following embodiments.

[0067] Taking the determination of the first taphole opening time after the scheduled maintenance and blasting of a blast furnace as an example, the relevant calculations for the scheduled maintenance shutdown charging and the first taphole opening after the scheduled maintenance and blasting are shown in Table 2. In Table 2, the number of batches of charge during the shutdown represents the distance from the hearth (tuyere centerline) to the throat, where 1 is the charge batch at the tuyere centerline and 38 is the charge batch at the throat. The volume from the blast furnace taphole centerline to the tuyere centerline is 619 m³. 3 The batch of ore for the shutdown was 100 tons, with a batch of iron of 62 tons and a slag ratio of 0.34 tons / ton of iron. The coke ratio, coal ratio, coke and pulverized coal fixed carbon of each batch of ore were collected in real time during the shutdown period. The relevant calculations were performed using the present invention. The calculation results are shown in Table 2. The specific calculation process is as follows.

[0068] Table 2 Blast Furnace Loading and Related Calculations During Scheduled Maintenance and Shutdown

[0069]

[0070]

[0071] 1. Calculation of carbon content in molten iron: The fuel ratio for each batch of material can be directly calculated from the coke ratio and coal ratio in the furnace. Then, the carbon content of molten iron can be obtained from the correspondence between the fuel ratio and the carbon content of molten iron (see Table 1).

[0072] The first batch of materials: FR1 = 500 + 80 = 580 kg / t, and the carbon content of the molten iron corresponding to the fuel ratio of 580 kg / t is 45 kg / t.

[0073] And so on.

[0074] Batch 38: FR38 = 380 + 140 = 520 kg / t, the carbon content of the molten iron corresponding to the fuel ratio of 520 kg / t is 47 kg / t.

[0075] The calculated carbon content of each batch of molten iron is shown in Table 2.

[0076] 2. Calculation of iron-to-carbon ratio per ton: During this scheduled maintenance shutdown, the effective fixed carbon content of coke was 87%, and the effective fixed carbon content of pulverized coal was 79%. The iron-to-carbon ratio per ton of each batch can be calculated from the coke ratio and coal ratio of each batch.

[0077] Batch 1 material: C 碳比1 =500×87%+80×79%=498.2kg / t.

[0078] And so on.

[0079] Batch 38: C 碳比38 =380×87%+140×79%=441.2kg / t.

[0080] 3. Calculation of air volume consumption per ton of iron: Based on the formula BV 耗风i =(C 碳比i -[C] i Calculate the air volume consumed per ton of iron per batch using (-130)×4.44.

[0081] Batch 1 material: BV 耗风1 =(498.2-45-130)×4.44=1435m 3 .

[0082] And so on.

[0083] Batch 38: BV 耗风38 =(441.2-47-130)×4.44=1173m 3 .

[0084] 4. Calculation of air consumption per batch and cumulative air consumption: using formula BV 批料耗风i =BV 耗风i ×M i Calculate the air volume consumed in smelting each batch of material.

[0085] Batch 1 material: BV 批料耗风1 =1435×62=88970m 3 .

[0086] And so on.

[0087] Batch 38: BV 批料耗风1 =1173×62=72729m 3 .

[0088] The air consumption from the first batch to the 38th batch was gradually accumulated to obtain the cumulative air consumption up to the Nth batch of material, where N = 1 to 38. The results are shown in Table 2.

[0089] 5. Calculation of the volume of slag and iron generated per batch and the cumulative volume of slag and iron generated.

[0090] From formula V 批料i =M i ÷6.7+M i ×SCR i ÷2 and V 累计 =ΣV 批料i Calculate the volume of slag and iron generated for each batch and the cumulative volume of slag and iron generated.

[0091] Batch 1 material: V 批料1 =60÷6.7+60×0.34÷2=19.79m3 .

[0092] And so on.

[0093] Batch 38: V 批料38 =60÷6.7+60×0.34÷2=19.79m 3 .

[0094] The slag and iron production from the first batch to the 38th batch were gradually accumulated to obtain the cumulative slag and iron production and air consumption when smelting up to the Nth batch, where N = 1 to 38. The results are shown in Table 2.

[0095] 6. Calculation of the regression equation for the cumulative generated slag and iron volume: The relationship between the cumulative air consumption and the cumulative generated slag and iron volume can be obtained by calculating the cumulative air consumption and the cumulative generated slag and iron volume, as shown in Table 3.

[0096] Table 3 Relationship between Cumulative Air Consumption and Cumulative Slag and Iron Generation Volume

[0097] Cumulative slag and iron production volume 19.79 39.59 59.38 79.17 98.97 118.76 138.56 Cumulative air consumption 711764 797899 884034 970169 1056304 1134704 1213104 Cumulative slag and iron production volume 158.35 178.14 197.94 217.73 237.52 257.32 277.11 Cumulative air consumption 1291504 1369903 1448303 1526703 1605103 1683502 1761902 Cumulative slag and iron production volume 296.91 316.70 336.49 356.29 376.08 395.87 415.67 Cumulative air consumption 1840302 1918702 1997101 2070271 2143440 2216610 2289779 Cumulative slag and iron production volume 435.46 455.26 475.05 494.84 514.64 534.43 554.22 Cumulative air consumption 2362948 2436118 2509287 2582457 2655626 2728355 2801084 Cumulative slag and iron production volume 574.02 593.81 613.61 633.40 653.19 672.99 692.78 Cumulative air consumption 2873813 2946542 3019271 Cumulative slag and iron production volume 712.57 732.37 752.16

[0098] A scatter plot of the data in Table 3 yields the cubic regression equation: y = 0.0007x³ - 1.4869x² + 4769.3x - 9350.3, where y represents the cumulative air consumption in cubic meters. 3 x: Cumulative volume of slag and iron generated, in meters (m). 3 .

[0099] 7. Calculation of maximum safe slag iron storage volume: Based on formula V 最大安全储渣铁体积 =V1×0.5×0.25 to calculate the maximum safe slag iron storage volume. The volume from the centerline of the blast furnace taphole to the lower edge of the tuyeres sleeve is 619m³. 3 The maximum safe slag iron storage volume is: V 最大安全储渣铁体积 =619 × 0.5 × 0.25 = 77.38m 3 .

[0100] 8. Determination of the first iron opening time after scheduled air supply: Using the maximum safe slag and iron storage volume as the cumulative slag and iron generation volume, substitute it into the regression equation y = 0.0007x³ - 1.4869x² + 4769.3x - 9350.3 to calculate the corresponding cumulative air consumption BV. 安全储渣铁累计耗风 That is, y is BV at this time. 安全储渣铁累计耗风 value.

[0101] y = 0.0007 × 77.38 3 -1.4869×77.38 2 +4769.3×77.38-9350.3=351097m 3 .

[0102] Therefore, it can be determined that the cumulative air volume after the blast furnace scheduled maintenance reached 351097 m³ / h. 3 At that time, the iron tap is opened to release the iron.

[0103] The recovery status of the blast furnace after scheduled maintenance and air supply is shown in Table 4.

[0104] Table 4 Recovery status after scheduled air supply inspection

[0105]

[0106] As can be seen from the table, when the first iron tapping time after scheduled maintenance is reasonably determined by adopting this method, the scheduled maintenance blasting effect of the blast furnace is good, the intensity of furnace front-end operations is reduced, and the blast furnace recovery process is guaranteed.

[0107] The above description is only a specific embodiment of the present invention, but the structural features protected by the present invention are not limited thereto. Any changes or modifications made by those skilled in the art within the scope of the present invention are covered by the patent scope of the present invention.

Claims

1. A method for determining the time of the first taphole opening after the scheduled blast furnace maintenance, characterized in that: Includes the following steps: Step 1: Collect the number of batches of furnace charge, batch iron quantity, slag ratio, coke ratio, coal ratio, and fixed carbon content of coke and pulverized coal for each section of the blast furnace hearth, belly, waist, body and throat during the blast furnace maintenance shutdown. Obtain the volume from the center line of the taphole to the lower edge of the tuyeres in the hearth area based on the blast furnace dimensions. Step 2: Calculate the fuel ratio and carbon ratio per ton of iron in each section of the blast furnace burden based on the iron-to-coke ratio, coal ratio, and fixed carbon content of coke and pulverized coal. C 碳比i =C coke × CR i +C Coal Powder × PCR i FR i =CR i +PCR i i: represents a section of the hearth, belly, waist, body, or throat. C 碳比i Iron-to-carbon ratio per ton (kg / t) C 焦炭i Effective fixed carbon content of coke, in % C 煤粉i Effective fixed carbon content of pulverized coal, in % FR i Fuel ratio to furnace, unit kg / t CR i : The ratio of iron to coke per ton of feed material during rest periods, in kg / t. PCR i : The ratio of iron to coal per ton of feed material during rest periods, in kg / t; Step 3: Carbon content of molten iron under different fuel ratios [C] i The corresponding carbon content of molten iron is 36-47 kg. The relationship between [C] and fuel ratio is as follows: Fuel ratio, kg: <550, [C], kg: 47; Fuel ratio, kg: 550≤X<600, [C], kg: 45; Fuel ratio, kg: 600≤X<800, [C], kg: 43; Fuel ratio, kg: 800≤X<1500, [C], kg: 40; Fuel ratio, kg: ≥1500, [C], kg: 36; X represents the fuel ratio per ton of iron. Step 4: Determine the blast volume per ton of iron consumed in each section of the blast furnace (hearth, belly, waist, body, and throat) based on the carbon ratio per ton of iron and the carbon content of the molten iron. BV 耗风i (C 碳比i -[C] i -130)×4.44 BV 耗风i Air consumption per ton of iron in each section of the blast furnace, in m³. 3 / t, C 碳比i Iron-to-carbon ratio per ton (kg / t) [C] i Carbon content of molten iron in each section of the blast furnace hearth, belly, waist, body, and throat, in kg / t. Step 5: Calculate the air consumption per batch and the slag-iron volume per batch during the smelting process based on the slag ratio and batch iron quantity in each section of the blast furnace. Then, starting from the hearth towards the throat, calculate the cumulative air consumption and cumulative slag-iron volume up to the Nth batch, where N is the number of batches charged during scheduled maintenance and downtime. In the calculation formula, 6.7 represents the specific gravity of molten iron, and 2 represents the specific gravity of slag. BV 批料耗风i =BV 耗风i ×M i BV 累计耗风i =BV 批料耗风i ×CH i In 批料i =M i ÷6.7+M i ×SCR i ÷2 BV 累计耗风 ΣBV 批料耗风i In 累计 =ΣV 批料i BV 批料耗风i The air consumption of each section of the blast furnace during the smelting of a batch, in cubic meters. 3 , M i Iron content of each batch of material in each section of the blast furnace, in tons per batch. BV 累计耗风i Cumulative air consumption in each section of the blast furnace, in cubic meters. 3 , CH i Number of material batches and unit batch for each section of the blast furnace. V 批料i The volume of slag and iron produced by smelting a batch of materials in each section of the blast furnace. SCR i Slag ratio of each section of the furnace, in tons (t / t). BV 累计耗风 : Cumulative air volume consumed during smelting up to the Nth batch, in m³ 3 , V 累计 : The cumulative slag and iron volume generated when smelting up to the Nth batch, in m³ 3 ; Step Six: The cumulative air consumption equation can be derived by regressing the cumulative slag and iron production volume from the smelting process to the Nth batch, as shown below: Cumulative air consumption regression equation: y = ax 3 +bx 2 +cx+d y: Cumulative air volume, in meters (m³) 3 x: Volume of slag and iron produced, in meters (m³) 3 a, b, c, and d are constants, and these constants vary depending on the blast furnace maintenance load. Step 7: Determine the maximum safe slag iron storage volume based on the volume from the centerline of the blast furnace taphole to the lower edge of the tuyeres and the hearth porosity. In the calculation formula, 0.5 is the safety factor and 0.25 is the hearth porosity. In 最大安全储渣铁体积 =V1×0.5×0.25 V 最大安全储渣铁体积 Maximum safe slag storage volume, in cubic meters (m³). 3 , V1: The volume from the centerline of the iron taphole to the lower edge of the vent sleeve; Step 8: The safe slag and iron storage volume is used as the cumulative slag and iron generation volume, and substituted into the cumulative air consumption regression equation: y = ax 3 +bx 2 The cumulative air consumption BV when the slag and iron production reaches the safe slag and iron storage volume is calculated using +cx+d. 安全储渣铁累计耗风 .

2. The method for determining the first taphole opening time after blast furnace scheduled maintenance, as described in claim 1, is characterized in that: Steps one through eight determine the cumulative air volume after the blast furnace scheduled maintenance, which reaches BV. 安全储渣铁累计耗风 This was the first time the iron ore was opened.

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