A quantitative control method for improving blast furnace slag and iron emissions

Abstract

The present invention discloses a quantitative control method for improving blast furnace slag iron discharge. The method analyzes the force of the material column according to the furnace type parameters, air supply parameters and blast furnace charging parameters, judges the state of the dead material column in the furnace after the iron is finished, and calculates the resultant force on the material column. Fr According to the state of the dead material column, calculate the minimum amount of slag iron required for the dead material column to float. According to the theoretical amount of iron produced and the actual amount of slag iron discharged, calculate the slag iron reserve in the furnace. According to the blast furnace slag iron deficiency, calculate the floating height of the dead material column caused by the slag iron deficiency, and calculate the blast furnace slag iron emission factor. IFIS , according to the slag iron emission factor IFIS By defining and calculating the slag iron emission factor, the present invention can help blast furnace operators adjust blast furnace parameters in a timely manner and reduce the impact of slag iron emissions on the blast furnace.

Description

Technical Field

[0001] The invention relates to a control method, in particular to a quantitative control method for improving blast furnace slag and iron emission, belonging to the technical field of blast furnace ironmaking. Background Art

[0002] The main task of blast furnace ironmaking is to produce qualified and sufficient molten iron, and slag discharge is one of the important links in the blast furnace ironmaking process. During the production process, it was found that slag discharge has a great influence on the movement of furnace charge and the composition of molten iron. When tapping, the wind pressure decreases, the material speed increases, and the molten iron temperature and silicon content decrease rapidly. After tapping, the wind pressure often increases, the material speed slows down, and the molten iron temperature and silicon content increase. Slag discharge often affects the pressure-volume relationship and the stability of the furnace thermal system. Therefore, slag discharge directly affects the stable and smooth operation of the blast furnace. However, there is no relevant record of a quantitative control method for the impact of slag discharge on blast furnace operation in the existing technology. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a quantitative control method for improving blast furnace slag and iron emissions, helping blast furnace operators to adjust blast furnace parameters in a timely manner and reduce the impact of slag and iron emissions on the blast furnace.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] A quantitative control method for improving blast furnace slag and iron emissions, characterized by comprising the following steps:

[0006] S1. Analyze the force on the material column based on the furnace parameters, air supply parameters, and blast furnace charging parameters to determine the state of the dead material column in the hearth after tapping, and calculate the resultant force Fr on the material column.

[0007] S2. Calculate the minimum amount of slag and iron required to float the dead material column according to its status;

[0008] S3. Calculate the slag iron reserves in the furnace based on the theoretical amount of iron generated and the actual amount of slag iron discharged;

[0009] S4. Calculate the floating height of the dead material column caused by the slag iron deficiency according to the blast furnace slag iron deficiency.

[0010] S5. Calculate the blast furnace slag and iron emission factor IFIS;

[0011] S6. Adjust the tapping parameters in time according to the slag iron emission factor IFIS. When the slag iron emission factor is close to the upper limit, take control measures in advance.

[0012] Furthermore, the step S1 is specifically as follows:

[0013] The dead material column is subjected to stress analysis. When the resultant force Fr of the dead material column is greater than 0, the dead material column is in a floating state. When Fr ≤ 0, the dead material column is in a submerged state.

[0014] The calculation method of the dead material column force Fr is as follows:

[0015] Fr=F △p +F i +F s +fG

[0016] Among them, F △p is the gas pressure difference in the furnace, Fi is the buoyancy of molten iron, Fs is the buoyancy of slag, f is the friction resistance of furnace wall, and G is the weight of charge.

[0017] Furthermore, the step S2 is specifically as follows:

[0018] According to the status of the dead material column, calculate the minimum amount of slag and iron required to float the dead material column;

[0019]

[0020] Among them, △M i ′+△M s ′ is the minimum amount of slag iron required for the dead material column to float, where △M i ′ represents the amount of iron, △M s ′ represents the amount of slag, Fr ​​is the resultant force acting on the dead material column, and ε is the coke porosity.

[0021] Furthermore, the step S3 is specifically as follows:

[0022] Calculate the slag iron reserve △M in the furnace according to the theoretical iron production and the actual slag iron discharge. i +△M s , where △M i is the iron deficiency, △M s is the amount of slag loss;

[0023] △M i +△M s =(△M i,c +△M s,c )-(△M i,p +△M s,p )

[0024] Among them, △M i,c +△M s,c is the theoretical amount of slag iron generated, which is calculated based on the batch iron amount and the number of batches in the actual production process. i,p +△M s,p The amount of slag and iron discharged is obtained based on the weight of the molten iron tank and the slag ratio.

[0025] Furthermore, the step S4 is specifically as follows:

[0026] According to the blast furnace slag iron deficiency, calculate the dead material column floating height △h caused by the slag iron deficiency. The specific calculation method is as follows:

[0027]

[0028] Among them, ρ i is the density of molten iron, S is the cross-sectional area of ​​the furnace, and is obtained according to the designed furnace size.

[0029] Furthermore, the step S5 is specifically as follows:

[0030] The slag and iron emission factor is calculated using the ratio of the floating height △h of the dead material column to the furnace height:

[0031]

[0032] Among them, H is the height from the bottom of the furnace to the upper edge of the furnace hearth, and △h represents the floating height of the dead material column due to slag iron deficiency.

[0033] Furthermore, in step S6, the control measures include one or a combination of increasing the drill bit size, reducing the tapping interval, increasing the tapping depth, and reducing the slag viscosity.

[0034] Furthermore, in step S6, the upper limit of the slag iron emission factor is determined as follows: when the slag iron emission factor increases and causes the blast furnace to reduce air flow, the corresponding slag iron emission factor can be used as the upper limit of blast furnace production control.

[0035] Compared with the prior art, the present invention has the following advantages and effects: The present invention provides a quantitative control method for improving blast furnace slag and iron emissions. By defining and calculating the slag and iron emission factor, it can help blast furnace operators adjust blast furnace parameters in a timely manner and reduce the impact of slag and iron emissions on the blast furnace. This method is simple and effective, and is convenient for production operators to calculate and analyze. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The present invention is a flow chart of a quantitative control method for improving blast furnace slag and iron emissions.

[0037] Figure 2 It is a calculation parameter table of an embodiment of the present invention.

[0038] Figure 3 It is a schematic diagram of a blast furnace type according to an embodiment of the present invention.

[0039] Figure 4 Schematic diagram of the changing trend of iron deficiency and blast furnace pressure difference during production of an embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to elaborate on the technical solutions adopted by the present invention to achieve the predetermined technical purpose, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments, and the technical means or technical features in the embodiments of the present invention can be replaced without creative work. The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0041] like Figure 1 As shown, a quantitative control method for improving blast furnace slag iron emissions of the present invention comprises the following steps:

[0042] S1. Analyze the forces acting on the material column based on the furnace type parameters, air supply parameters, and blast furnace charging parameters to determine the state of the dead material column in the hearth after tapping is complete. The completion of tapping indicates no slag iron loss, and the resultant force Fr acting on the material column is calculated.

[0043] Fr=F △p +F i +F s +fG

[0044] Among them, F △p is the gas pressure difference in the furnace, Fi is the buoyancy of molten iron, Fs is the buoyancy of slag, f is the friction resistance of furnace wall, and G is the weight of charge.

[0045] according to Figure 2 According to the calculation parameters given in the attached table, the gravity of the charge G is 33916991.2N, the buoyancy of the slag and iron Fi+Fs is 9462936.3N, the friction force f is 2781103.1N, and the buoyancy of the gas pressure difference is 20232225.5N. The final calculated resultant force Fr is -1440726.3N, and the state of the dead material column is sinking to the bottom of the furnace.

[0046] S2. Calculate the minimum amount of slag and iron required to float the dead material column based on its status.

[0047]

[0048] Among them, △M i ′+△M s ′ is the minimum amount of slag iron required for the dead material column to float, where △M i ′ represents the amount of iron, △M s ′ represents the amount of slag, Fr ​​is the resultant force acting on the dead material column, and ε is the coke porosity.

[0049] Fr calculated according to step S1, and Figure 2Based on the porosity parameters given in the attached table, it can be calculated that the minimum amount of slag iron required for the dead material column to float is 75.73t. This means that when the total amount of slag iron exceeds 75.73t during the production process, the state of the dead material column will change from sinking to floating.

[0050] S3. Calculate the slag iron reserve △M in the furnace based on the theoretical iron production and the actual slag iron discharge. i +△M s , where △M i is the iron deficiency, △M s The amount of slag loss.

[0051] △M i +△M s =(△M i,c +△M s,c )-(△M i,p +△M s,p )

[0052] Among them, △M i,c +△M s,c is the theoretical amount of slag iron generated, which is calculated based on the batch iron amount and the number of batches in the actual production process. i,p +△M s,p The amount of slag and iron discharged is obtained based on the weight of the molten iron tank and the slag ratio.

[0053] In this example, there are 10 batches of materials, the theoretical total iron amount is 626.8t, the actual iron output is 513.8t, and the calculated iron loss is 113.0t and the slag loss is 36.2t.

[0054] S4. According to the blast furnace slag iron deficiency, calculate the floating height △h of the dead material column caused by the slag iron deficiency.

[0055]

[0056] Among them, ρ i is the density of molten iron, which is 7000kg / m 3 S is the cross-sectional area of ​​the furnace, which is obtained according to the designed furnace size. In this example, the furnace diameter is 10.53m and the cross-sectional area is 87.04m. 2 .

[0057] According to step S2 and step S3, the minimum slag iron amount △M of the dead material column can be obtained. i ′+△M s ′ and blast furnace slag iron loss △M i +△M s , substituting into the above formula, we get the floating height △h of the dead material column to be 0.12m.

[0058] S5. Calculate the blast furnace slag and iron emission factor IFIS.

[0059] The slag and iron emission factor is calculated using the ratio of the floating height △h of the dead material column to the furnace height:

[0060]

[0061] Among them, Figure 3 As shown, H is the height from the furnace bottom to the upper edge of the furnace hearth, and △h represents the floating height of the dead material column due to slag iron deficiency.

[0062] In this example, the height from the furnace bottom to the upper edge of the furnace hearth is 6.4m. Based on the floating height of the dead material column calculated in step 4, the IFIS is 0.0188.

[0063] During production, it was found that when IFIS exceeds 0.0188, the blast furnace pressure differential is high and the air volume is low. Therefore, 0.0188 is set as the upper control limit for IFIS. If IFIS approaches the upper limit during production, measures can be taken in advance, such as reducing the tapping interval, increasing the drill bit size, increasing the taphole depth, and reducing the slag viscosity, to minimize the impact of tapping on blast furnace production.

[0064] S6. Adjust the tapping parameters in time according to the slag iron emission factor IFIS. When the slag iron emission factor approaches the upper limit, take control measures in advance. Figure 4 shown.

[0065] Control measures include increasing drill bit size, reducing tapping intervals, increasing taphole depth, and reducing slag viscosity, or a combination thereof. The upper limit of the slag and iron emission factor is determined as follows: when an increase in the slag and iron emission factor leads to a reduction in blast furnace air flow, the corresponding slag and iron emission factor can be used as the upper limit for blast furnace production control.

[0066] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the present profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical content disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement of the above embodiments made according to the technical essence of the present invention, within the spirit and principles of the present invention, without departing from the content of the technical solution of the present invention, shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A quantitative control method for improving blast furnace slag and iron emissions, characterized in that The following steps are involved: S1. Analyze the force on the material column based on the furnace type parameters, air supply parameters and blast furnace charging parameters, determine the state of the dead material column in the furnace after the iron is tapped, and calculate the resultant force on the material column. Fr ; S2. Calculate the minimum amount of slag and iron required to float the dead material column according to its status; S3. Calculate the slag iron reserves in the furnace based on the theoretical amount of iron generated and the actual amount of slag iron discharged; S4. Calculate the floating height of the dead material column caused by the slag iron deficiency according to the blast furnace slag iron deficiency. S5. Calculation of blast furnace slag and iron emission factors IFIS ; The step S5 is specifically as follows: Utilize the floating height of the dead material column Calculate the slag and iron emission factor based on the ratio of the furnace height to the furnace hearth height: in, H It is the height from the bottom of the furnace to the upper edge of the furnace. Indicates the floating height of the dead material column due to slag iron deficiency; S6. Based on the slag and iron emission factor IFIS , timely adjust the tapping parameters, and take control measures in advance when the slag iron emission factor is close to the upper limit; In step S6, the control measures include increasing the drill bit size, reducing the tapping interval, increasing the tapping depth, and reducing the slag viscosity, or a combination thereof; In step S6, the upper limit of the slag and iron emission factor is determined as follows: when the slag and iron emission factor increases and causes the blast furnace to reduce air flow, the corresponding slag and iron emission factor can be used as the upper limit of blast furnace production control.

2. A quantitative control method for improving blast furnace slag and iron emissions according to claim 1, characterized in that: The step S1 is specifically as follows: The dead material column is subjected to stress analysis. Fr When >0, the dead material column is in a floating state. Fr When ≤0, the dead material column is in a submerged state; Dead material column force Fr The calculation method is as follows: in, is the gas pressure difference in the furnace, Fi is the buoyancy of the molten iron, Fs is the buoyancy of the slag, f is the friction resistance of the furnace wall, G is the charge gravity.

3. The quantitative control method for improving blast furnace slag and iron emissions according to claim 1, characterized in that: The step S2 is specifically as follows: According to the status of the dead material column, calculate the minimum amount of slag and iron required to float the dead material column; in, The minimum amount of slag and iron required for the dead material column to float, Indicates the amount of iron, Indicates the amount of slag, Fr is the resultant force on the dead material column, is the coke porosity.

4. A quantitative control method for improving blast furnace slag and iron emissions according to claim 3, characterized in that: The step S3 is specifically as follows: Calculate the slag iron reserves in the furnace according to the theoretical iron production and the actual slag iron discharge ,in Iron deficiency, is the amount of slag loss; in, The theoretical amount of slag iron generated is calculated based on the batch iron amount and the number of batches in the actual production process. The amount of slag and iron discharged is obtained based on the weight of the molten iron tank and the slag ratio.

5. A quantitative control method for improving blast furnace slag and iron emissions according to claim 4, characterized in that: The step S4 is specifically as follows: According to the blast furnace slag iron deficiency situation, calculate the floating height of the dead material column caused by the slag iron deficiency , the specific calculation method is as follows: in, is the density of molten iron, S is the cross-sectional area of ​​the furnace hearth, which is obtained according to the designed furnace size.

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