A method for evaluating the activity of a blast furnace hearth by using the slag iron retention index of the hearth

Abstract

The application provides a method for evaluating the activity of a blast furnace hearth by using a slag-iron retention index of the blast furnace hearth, and is characterized in that: a slag-iron retention amount model is constructed based on a calculation model of a slag-iron retention rate and a dead material column volume, a slag-iron retention index is obtained by combining parameters of the blast furnace hearth, and the blast furnace hearth activity is evaluated by using the slag-iron retention index. The method uses a multi-factor coupling analysis method to evaluate the contribution degree of factors affecting the slag-iron retention amount, constructs a slag-iron retention index model integrating slag-iron components, slag-iron temperatures, air blast parameters and tapping parameters, and realizes the purpose of scientifically and accurately evaluating the blast furnace hearth activity. The application considers the influence of various production parameters of the blast furnace on the blast furnace hearth activity, establishes a model for scientifically and systematically evaluating the blast furnace hearth activity, and realizes online monitoring of the blast furnace hearth activity in actual application, thereby providing guidance for the production regulation and control of the blast furnace.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of blast furnace ironmaking, and in particular to a method for evaluating the activity of a blast furnace hearth by using a slag-iron retention index of the blast furnace hearth. BACKGROUND

[0002] As an important part of the steel industry, blast furnace ironmaking shoulders the heavy responsibility of rational utilization of resources and reduction of CO2 emissions for the entire industry. It is the trend of modern blast furnace technology development to achieve high yield, high quality, low consumption, long service life and safe production of blast furnaces, and the key lies in how to maintain a good working state of the blast furnace hearth. The working state of the hearth is closely related to the thermal state, gas and liquid permeability state, blast and slag-iron discharge state of the blast furnace, and is the basis for stable operation and long service life of the blast furnace.

[0003] Currently, the activity of the blast furnace hearth is mainly judged based on actual production experience in blast furnace production, and the activity of the blast furnace hearth is indirectly reflected by using characterization indicators. This method has certain hysteresis and theoretical limitations. In addition, an invention patent (application number CN201910694721.X) discloses a method for quantifying the activity of a blast furnace hearth, which is based on the slag-iron flow resistance coefficient f L , a new hearth activity index NHA is constructed, and the quantification of the activity of the blast furnace hearth is realized. However, this method mainly considers the influence of slag-iron parameters, and does not consider the influence of other factors (such as blast parameters) on the activity of the blast furnace hearth, resulting in low accuracy of the quantification result. Moreover, the parameters required for characterization are quite complex and cannot be directly obtained in blast furnace production, making it difficult to be directly applied to blast furnace production.

[0004] An invention patent (application number CN201810596710.3) discloses a system, method and device for detecting the activity of a blast furnace hearth. By simulating the process of slag-iron molten liquid passing through coke particles in the blast furnace hearth, the slag-iron retention rate is calculated, and the activity of the blast furnace hearth is reflected to provide theoretical guidance for actual production. This invention proposes to use the slag-iron retention rate to characterize the activity of the blast furnace hearth, which can characterize the potential activity of the blast furnace hearth. However, it does not consider the influence of the lower part of the blast furnace on the degree of activity of the blast furnace hearth and the state of the dead material column in the blast furnace hearth. Under the condition of change of the operation system of the blast furnace, the accuracy of predicting the activity of the blast furnace hearth needs to be improved.

[0005] From the prior art, it can be known that the existing evaluation and calculation models for the activity of the blast furnace hearth are not comprehensive enough, and the actual production conditions of the blast furnace, the shape and state of the dead material column, and the influence of various production parameters on the activity of the blast furnace hearth are not fully considered in the calculation process. Therefore, there is currently no method that can accurately and timely reflect the activity of the blast furnace hearth in accordance with the actual production of the blast furnace.

[0006] Therefore, it is necessary to design an improved method for evaluating the activity of the blast furnace hearth by using a slag-iron retention index of the blast furnace hearth to solve the above problems. Summary of the Invention

[0007] The purpose of this invention is to provide a method for evaluating blast furnace hearth activity using the slag and iron retention index. Starting from the actual practice of blast furnace smelting, this method quantitatively analyzes the relative importance of various blast furnace production parameters on hearth activity, and incorporates highly correlated parameters into the slag and iron retention model. Combined with blast furnace hearth parameters, a slag and iron retention index model is obtained to characterize blast furnace hearth activity. This establishes a scientific and systematic model for evaluating blast furnace hearth activity, which, when applied to actual blast furnace production, can promptly and accurately reflect blast furnace hearth activity, thus guiding actual blast furnace production.

[0008] To achieve the above-mentioned objective, this invention provides a method for evaluating hearth activity using the slag and iron retention index in the blast furnace hearth, comprising the following steps:

[0009] S1. Based on the calculation model of slag and iron retention rate and dead material column volume in the hearth, construct a slag and iron retention model;

[0010] The slag and iron retention model: In the formula, h is the slag and iron retention rate in the hearth, %; V d Let m be the volume of the dead material column. 3 ;

[0011] The calculation model for the slag and iron retention rate in the hearth is as follows: In the formula C pm α is the number of capillaries, dimensionless; α is the viscosity correction factor, dimensionless; β is the temperature correction factor, dimensionless.

[0012] The calculation model for the volume of the dead material column is as follows: First, the length of the blast furnace tuyeres is calculated based on the blast parameters. Then, combined with the tapping parameters, the dimensional parameters required to calculate the volume of the dead material column are obtained based on the principle of similar triangles. Finally, the calculation model for the volume of the dead material column is obtained.

[0013] S2. Combine the slag and iron retention model from step S1 with different blast furnace hearth specifications to obtain the slag and iron retention index model: In the formula, V L This refers to the volume of the blast furnace hearth.

[0014] S3. Based on the slag and iron retention index model obtained in step S2, obtain the changing trend of the slag and iron retention index in actual blast furnace production, so as to evaluate the hearth activity of different blast furnaces.

[0015] As a further improvement of the present invention, in step S1, the number of capillaries characterizes the actual slag-iron coke-crossing process in the blast furnace, and its calculation formula is as follows:

[0016] In the formula, ρ Lis the density of blast furnace slag, kg / m 3 ; g is the acceleration of gravity, m / s 2 ; is the coke shape factor, dimensionless; d p is the coke diameter of the hearth, m; σ L is the surface tension of the slag, N / m; θ is the contact angle between the slag and the coke, °; ε is the dead manhole void fraction, dimensionless.

[0017] As a further improvement of the present application, the method for determining the coke diameter of the hearth is: based on the blast furnace hearth damage investigation and the coke extraction results of the tuyere, introducing the CSR, CRI and the coke particle size parameters into the blast furnace, constructing the relationship between the coke diameter of the hearth and the coke into the blast furnace, and obtaining the coke diameter of the hearth.

[0018] As a further improvement of the present application, in step S1, the determination of the calculation model of the dead manhole volume specifically comprises the following steps:

[0019] SS1, the dead manhole is modeled and processed, and it is assumed that the dead manhole of the blast furnace is composed of two parts, which presents a combined shape of a right circular cone and an inverted circular table;

[0020] SS2, according to the relationship between the radius of the blast furnace hearth and the length of the blast furnace tuyere rotation zone, the dead manhole tuyere platform radius is calculated, and the circular cone section diameter of the dead manhole in the same plane with the tuyere platform is calculated according to the dead manhole tuyere platform radius;

[0021] SS3, according to the principle of similar triangles, the dead manhole corner section radius is obtained, and then the distance from the dead manhole corner to the lower surface of the dead manhole circular table is calculated;

[0022] SS4, the calculation model of the dead manhole volume is obtained:

[0023] In the formula, r d is the dead manhole corner section radius, m; r dd is the lower surface radius of the dead manhole circular table, m; h dd is the distance from the dead manhole corner to the lower surface of the dead manhole circular table, m; h du is the distance from the top of the upper part of the dead manhole to the corner, m.

[0024] As a further improvement of the present application, in step SS3, the calculation formula of the dead manhole corner section radius is:

[0025] In the formula, r d is the dead manhole corner section radius, m; r h is the diameter of the hearth, m; l t is the taphole depth, m; h tHeight of dead man above tuyere, m; h th Height of dead man from highest point to corner, m; h td Distance from iron notch plane to corner, m.

[0026] As a further improvement of the present application, the formula for calculating the distance from the dead man corner to the lower surface of the dead man circular platform is: h dd = (r d -r dd ) tan θ;

[0027] In the formula, h dd is the distance from the dead man corner to the lower surface of the dead man circular platform, m; r d is the radius of the dead man corner section, m; and θ is the dead man corner.

[0028] As a further improvement of the present application, the viscosity correction coefficient is calculated according to the slag viscosity and the standard slag viscosity at 1500℃.

[0029] As a further improvement of the present application, the temperature correction coefficient is calculated according to the slag melting temperature and the molten iron temperature.

[0030] As a further improvement of the present application, in step S1, the formula for calculating the slag viscosity is:

[0031] In the formula, μ is the slag viscosity, Pa·s; t is the slag temperature, ℃; E is the kinetic energy of the blast, kg·m / s; A w is the key correlation coefficient, dimensionless.

[0032] As a further improvement of the present application, the formula for calculating the slag melting temperature is: T r = 1204.6 + 5.902·m(Al2O3) - 2.961·m(MgO) + 90.286R;

[0033] In the formula, m(Al2O3) is the mass content of Al2O3 in the blast furnace slag, wt%; m(MgO) is the mass content of MgO in the blast furnace slag, wt%; and R is the basicity, dimensionless, which is the mass ratio of CaO to SiO2.

[0034] The beneficial effects of the present application are:

[0035] 1. The method for evaluating the activity of the hearth of a blast furnace by using the slag iron retention index of the hearth of the blast furnace, based on the calculation model of the slag iron retention rate and the volume of the dead material column, constructs a slag iron retention amount model, obtains the slag iron retention index by combining the slag iron retention amount model with the size of the hearth of the blast furnace, and evaluates the activity of the hearth of the different blast furnaces. The slag iron retention amount of the hearth is calculated in the slag iron retention index model, the contribution degree of the factors affecting the slag iron retention amount is evaluated by using the multi-factor coupling analysis method, and the factors with high correlation are introduced into the slag iron retention amount model, thereby improving the accuracy of the model. The present application starts from the actual smelting of the blast furnace, comprehensively considers the influence of the various production parameters of the blast furnace on the activity of the hearth in the actual production, establishes a model for scientifically and systematically evaluating the activity of the hearth of the blast furnace, and when applied to the actual production of the blast furnace, can timely and accurately reflect the activity of the hearth of the blast furnace, thereby playing a role in guiding the actual production of the blast furnace.

[0036] 2. In the present application, when the calculation model of the slag iron retention rate is established, the retention rate is corrected from two aspects of the chemical stability and the thermal stability of the slag, so that it is more consistent with the actual production of the blast furnace; in the calculation of the capillary number which is the parameter for characterizing the actual slag iron penetration process of the blast furnace, the calculation method of the coke particle size of the hearth is introduced, and the accuracy of the coke particle size of the hearth is higher than that of the traditional coke particle size entering the blast furnace. When the calculation model of the volume of the dead material column is established, since the size of the dead material column is related to the size of the tuyere rotation zone of the blast furnace, the depth of the iron notch and the design parameters of the blast furnace, the blast parameters and the tapping parameters are introduced, and the size of the volume of the dead material column is more consistent with the actual production of the blast furnace. Therefore, the slag iron retention index model for evaluating the activity of the hearth of the blast furnace in the present application is a relatively comprehensive model integrating the slag iron composition, the slag iron temperature, the blast parameters and the tapping parameters, and realizes the rapid and accurate evaluation of the activity of the hearth of the blast furnace in the actual production.

[0037] 3. All the calculation parameters in the slag iron retention index model in the present application are the report parameters of the actual production of the blast furnace, so the model can be directly used in the actual production of the blast furnace, the input of the parameters is realized in real time, the activity of the hearth of the blast furnace is monitored and predicted in real time, the model is also applicable to the production of different specifications of the blast furnace, and the practicability and universality are high. In addition, the quantitative influence relationship of each parameter on the slag iron retention amount / activity of the hearth is given in the model, which provides theoretical guidance for the blast furnace production workers to control the activity of the hearth in the actual production. Compared with the activity evaluation model of the hearth in the prior art which has great limitations, is not comprehensive in considering the parameters and is greatly affected by the fluctuation of the blast furnace, the slag iron retention index model for evaluating the activity of the hearth of the blast furnace in the present application has the advantages of high accuracy, good timeliness and high stability of the results. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 It is a flowchart of the method for evaluating the activity of the hearth of a blast furnace by using the slag iron retention index of the hearth of the blast furnace.

[0039] Figure 2 The result graph of the contribution degree of each factor to the calculation model of the dead man column volume.

[0040] Figure 3 The result graph of the contribution degree of each factor to the calculation model of the dead man column volume.

[0041] Figure 4 The structural schematic diagram of the dead man column, wherein (a) is a structural schematic diagram of the dead man column of the blast furnace, and (b) is a structural schematic diagram of the dead man column in (a). DETAILED DESCRIPTION

[0042] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be described in detail below in combination with the drawings and specific embodiments.

[0043] Here, it also needs to be noted that, in order to avoid the present application being obscured by unnecessary details, only the structures and / or processing steps closely related to the scheme of the present application are shown in the drawings, and other details not closely related to the present application are omitted.

[0044] In addition, it also needs to be noted that the term “comprise”, “contain” or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device.

[0045] Please refer to Figure 1 As shown in the drawings, the present application provides a method for evaluating the activity of the hearth of a blast furnace by using the slag iron retention index of the hearth, which comprises the following steps:

[0046] S1, constructing a slag iron retention amount model based on the calculation model of the slag iron retention rate and the dead man column volume;

[0047] S2, obtaining a slag iron retention index model by combining the slag iron retention amount model in step S1 with different specifications of the hearth of the blast furnace: In the formula, V L is the volume of the hearth of the blast furnace;

[0048] S3, obtaining the change trend of the slag iron retention index in the actual production of the blast furnace according to the slag iron retention index model obtained in step S2, so as to evaluate the activity of the hearth of different blast furnaces.

[0049] Specifically, in step S1, the slag iron retention amount model is: In the formula, h is the slag iron retention rate of the hearth (%), V d is the dead man column volume (m 3 );

[0050] The calculation model of the slag-iron retention rate of the hearth: In the formula, C pm is the capillary number, dimensionless; a is the viscosity correction coefficient, dimensionless; and b is the temperature correction coefficient, dimensionless. The viscosity correction coefficient a is calculated according to the slag viscosity μ and the standard viscosity μ0 of the slag at 1500°C; and the temperature correction coefficient b is calculated according to the slag melting temperature T r and the hot metal temperature T.

[0051] The calculation model of the dead material column volume: the length of the blast furnace tuyere rotation zone is calculated according to the blast parameters, and the size parameters required for calculating the dead material column volume are obtained according to the similar triangle principle in combination with the tapping parameters, and finally the calculation model of the dead material column volume is obtained.

[0052] Specifically, the calculation formula of the slag viscosity is: In the formula, μ is the slag viscosity (Pa·s), t is the slag temperature (°C), E is the blast kinetic energy (kg·m / s), A w is the bond correlation coefficient, dimensionless. In some specific embodiments, μ is the viscosity of the CaO-SiO2-Al2O3-MgO quaternary slag system, and for the CaO-SiO2-Al2O3-MgO quaternary slag system, In the formula, A1, A2, A3, A4, A5, A6, and A7 are the correlation coefficients of Si-O-Si, Si-O-Al, Si-O-Ca, Al-O-Ca, Si-O-Mg, Al-O-Mg, and Al-O-Al, respectively.

[0053] The calculation formula of the slag melting temperature is: T r = 1204.6 + 5.902·m(Al2O3) - 2.961·m(MgO) + 90.286R, in which T r is the slag melting temperature (°C), m(Al2O3) is the mass content of Al2O3 in the blast furnace slag (wt%), m(MgO) is the mass content of MgO in the blast furnace slag (wt%), and R is the basicity (dimensionless), which is the mass ratio of CaO to SiO2.

[0054] Please refer to Figure 2 As shown in the figure, the influencing factors of the slag-iron retention rate mainly include the slag parameters, the coke parameters, the hot metal temperature (T), the dead material column porosity (ε), and the like. The specific parameters include the slag basicity, the slag magnesium-aluminum ratio, the coke particle size, the coke CRI, the coke CSR, the hot metal temperature, the slag titanium content, and the permeability index. By combining the actual data of the blast furnace production, the relationship between the slag-iron retention rate and the above factors is studied, the contribution degree of the above factors to the slag-iron retention rate is quantitatively determined, and the calculation model of the slag-iron retention rate is obtained. Figure 1The result graph of the contribution degree of each factor to the slag iron retention rate shows that the contribution degree of the above factors is in the following order: the contribution degree of the molten iron temperature is 35%, the contribution degree of the CSR is 26%, the contribution degree of the coke particle size is 13%, the contribution degree of the CRI is 12%, the contribution degree of the slag basicity is 8%, the contribution degree of the slag magnesium-aluminum ratio is 5%, and the contribution degree of the slag titanium content is 1%.

[0055] Therefore, in the establishment of the calculation model of the slag iron retention rate, the retention rate is corrected from two aspects of the chemical stability and the thermal stability of the slag, the flowability correction factor (i.e. the viscosity correction coefficient a) and the temperature correction factor (i.e. the temperature correction coefficient β) are introduced, so that the model is more in line with the actual production of the blast furnace; in the calculation of the capillary number representing the actual slag iron coke penetration process of the blast furnace, due to the complex environment of the blast furnace, the coke particle size, the CSR and the CRI are all changed from the charging to the tuyere, the accuracy of the charging coke particle size is poor in the traditional method; therefore, the charging coke particle size is replaced by the hearth coke particle size in the present application, so that the influence of the charging coke particle size on the actual production process of the blast furnace is eliminated, and the accuracy of the slag iron retention rate model is greatly improved.

[0056] Specifically, the flowability of the slag is affected by the slag composition, the slag density, the slag surface tension, the slag viscosity and the slag melting temperature, so the calculation formula of the capillary number representing the actual slag iron coke penetration process of the blast furnace is wherein, ρ L is the blast furnace slag density (kg / m 3 ), 2 , is the coke shape factor (dimensionless), d p is the hearth coke diameter (m), σ L is the slag surface tension (N / m), θ is the contact angle between the slag and the coke (generally 120°), and ε is the dead material column void fraction;

[0057] wherein, the hearth coke diameter d p is determined by: based on the blast furnace hearth damage investigation and the tuyere coke taking results, introducing the CSR, the CRI and the charging coke particle size parameters, constructing the relationship between the hearth coke diameter and the charging coke, and obtaining the hearth coke diameter.

[0058] The calculation formula of the blast furnace slag density is: ρ t =∑X MO ·ρ MO , wherein, ρ LBlast furnace slag density (kg / m³) 3 ), X MO ρ represents the molar percentage (%) of each component. MO Density of each component (kg / m³) 3 );

[0059] Formula for calculating the surface tension of slag: σ l =∑X MO ·σ MO In the formula σ L X represents the surface tension of the slag (N / m). MO σ represents the molar percentage (%) of each component. MO The surface tension of each component is (N / m).

[0060] Please see Figure 3 As shown, by evaluating the contribution of factors affecting the slag and iron retention in the blast furnace hearth (blast volume, oxygen content, blast temperature, blast pressure, and pulverized coal injection), and combining actual blast furnace production data, the contribution of each factor was assigned according to statistical principles. The results are as follows: blast volume contribution is 31%, taphole depth is 26%, blast temperature contribution is 18%, blast pressure contribution is 16%, pulverized coal injection contribution is 6%, and oxygen content contribution is 3%. The correlation ranking with the slag and iron retention model is: blast volume > taphole depth > blast temperature > blast pressure > pulverized coal injection > oxygen content. Therefore, this invention introduces blast parameters and tapping parameters into the calculation model of the dead material column volume, and then into the slag and iron retention model, to improve the quantitative accuracy of the slag and iron retention index model for the activity of the blast furnace hearth.

[0061] Specifically, the determination of the calculation model for the dead material column volume includes the following steps:

[0062] SS1. Model the deadweight column, assuming it consists of two parts, exhibiting a combination of a right circular cone and an inverted frustum. Specifically, approximate the irregular shape of the upper deadweight column in the blast furnace as an ideal "right circular cone," and the irregular shape of the lower deadweight column as an ideal "inverted frustum," with the deadweight column corners ranging from 30° to 40°. Figure 4 As shown;

[0063] SS2. Based on the relationship between the radius of the blast furnace hearth and the length of the blast furnace tuyeres, the radius of the dead material column tuyeres platform is calculated, and the diameter of the conical section of the dead material column on the same plane as the tuyeres platform is calculated based on the radius of the dead material column tuyeres platform.

[0064] SS3, such as Figure 4As shown, the positive conical dead man column has two groups of similar triangles, i.e. above the tuyere plane, above the taphole plane and above the dead man column conical angle; according to the principle of similar triangles, the dead man column conical angle cross section radius is obtained, and then the distance from the dead man column corner to the lower surface of the dead man column circular table is calculated;

[0065] SS4, obtaining the calculation model of the dead man column volume:

[0066] In the formula, r d is the dead man column conical angle cross section radius (m), r dd is the dead man column circular table lower surface radius (m), h dd is the distance from the dead man column corner to the dead man column circular table lower surface (m), h du is the distance from the dead man column upper top to the corner (m).

[0067] In step SS3, the calculation formula of the dead man column conical angle cross section radius is: In the formula, r d is the dead man column conical angle cross section radius (m), r h is the furnace hearth diameter (m), l t is the taphole depth (m), h t is the height of the dead man column above the tuyere (m), h th is the height from the highest position of the dead man column to the dead man column corner (m), h td is the distance from the dead man column taphole plane to the corner (m).

[0068] The calculation formula of the distance from the dead man column corner to the dead man column circular table lower surface is h dd = (r d -r dd ) tan θ. In the formula, h dd is the distance from the dead man column corner to the dead man column circular table lower surface (m), r d is the dead man column conical angle cross section radius (m); θ is the dead man column corner; in some specific embodiments, the dead man column corner θ is 35°.

[0069] In step SS2, the calculation formula of the blast furnace tuyere rotation zone length is: In the formula, D R is the tuyere rotation zone length (m), E is the blast dynamic energy (kg·m / s), P c is the coal injection amount (kg / h), and n is the tuyere number (pcs).

[0070] In which, the calculation formula of the blast dynamic energy is: The calculation formula of the mass is: The calculation formula of the velocity is

[0071] In the above formula, V B is the blast furnace blast volume (m 3 / min), V O2 is the total oxygen volume (m 3 / min), V' O2 is the total oxygen volume of the oxygen-enriched oxygen volume added after the humidity meter is deducted (m 3 / min), S f is the tuyere area (m 2 ), T B is the hot blast temperature (K), P B is the hot blast pressure (kPa), W B is the blast humidity (kg / m 3 ), n is the tuyere number (pcs), P0 is the standard state pressure (K), and T0 is the standard state temperature (kPa).

[0072] As known from the foregoing, all the calculation parameters in the slag iron retention index model of the present application are report parameters of actual production of the blast furnace, so the model can be directly used in actual production of the blast furnace, real-time parameter input is performed, real-time monitoring and prediction of the activity of the blast furnace hearth are performed, and the model has high practicability and universality; the model can be directly applied to different blast furnace production lines, can timely and accurately reflect the activity of the blast furnace hearth, and has the significance of guiding actual production of the blast furnace.

[0073] Embodiment 1

[0074] The present embodiment provides a method for evaluating the activity of the hearth by using the slag iron retention index of the blast furnace hearth, and combines the method with the actual production of the blast furnace, and includes the following steps:

[0075] S1, arrange the values required for calculating the slag iron retention amount of the blast furnace hearth, and collect the data parameters of a blast furnace from January to May as shown in Table 1;

[0076] Table 1: Actual production parameters of a blast furnace

[0077] January February March April May Alkalinity 1.15 1.16 1.15 1.15 1.17 Magnesium to aluminum ratio 0.60 0.59 0.58 0.57 0.57 Coke particle size (mm) 50.24 50.40 51.87 51.32 51.25 CRI (%) 22.80 25.00 23.79 24.50 23.54 CSR (%) 68.90 66.00 63.30 66.50 65.20 Molten iron temperature (°C) 1508.00 1505.00 1507.00 1506.00 1506.00 Coal gas utilization rate (%) 43.57 41.85 43.20 42.59 42.26 coefficient (t / d / m 3 )]]> 4.06 3.91 3.99 4.033 4.02 Air blast volume (m 3 / min) 2827.00 2822.00 2811.00 2823.00 2828.00 Blowing temperature (°C) 1184.00 1200.00 1204.00 1204.00 1204.00 Blowing pressure (kPa) 375.00 374.00 369.00 371.00 374.00 Amount of oxygen (m 3 / min) 217.00 215.00 240.00 249.00 250.00 Coal injection rate (kg / h) 25427.00 26334.00 26552.00 27034.00 27712.00 Fuel ratio (kg / t) 517.10 525.30 519.00 522.60 524.70

[0078] S2, establish a calculation model of the slag iron retention rate of the hearth: α is a viscosity correction coefficient, which is calculated according to the viscosity μ of the slag system and the standard viscosity of the slag system under the condition of 1500℃; β is a temperature correction coefficient, which is calculated according to the slag melting temperature T r and the molten iron temperature;

[0079] wherein,

[0080] T r = 1204.6 + 5.902·m(Al2O3) - 2.961·m(MgO) + 90.286R;

[0081] Based on the blast furnace hearth damage investigation and tuyere coke sampling results, CSR, CRI, and coke particle size parameters were introduced to construct the relationship between the hearth coke diameter and the coke entering the furnace, thus obtaining the hearth coke diameter d. p ;ρ l =∑X MO ·ρ MO , σ t =∑X MO ·σ MO θ is 120°;

[0082] It should be noted that the calculation method for the coke diameter d0 introduced when calculating the hearth coke diameter is as follows: The coke is sieved and divided into six particle size grades: <10mm, 10-20mm, 20-30mm, 30-40mm, 40-50mm, and >50mm. Their respective mass percentages are C1, C2, C3, C4, C5, and C6. The median value of each grade is multiplied by its respective mass percentage (5mm for <10mm particles, 55mm for >50mm particles) to calculate the average coke particle size. The specific calculation formula is as follows: d0 is the particle size of the coke entering the furnace (m), and i is the serial number, with a value of 1 to 6;

[0083] S3. Establish a calculation model for the volume of the dead material column: In the formula, r d r is the radius (m) of the dead material column cone section. dd Let h be the radius (m) of the lower surface of the frustum of the dead material column. dd h is the distance (m) from the corner of the deadstock column to the lower surface of the truncated cone of the deadstock column. du The distance (m) from the top of the dead material column to the corner; where, h dd =(r d -r dd tanθ;

[0084] like Figure 4 As shown, the dimensional parameters in the above formula can be obtained based on the principle of similar triangles, where r t The value is obtained by subtracting the depth of the blast furnace tuyeres from the hearth diameter, and then subtracting 0.5. The formula for calculating the length of the blast furnace tuyeres is: In the formula, The formula for calculating mass is: The formula for calculating speed is:

[0085] S4. Based on the calculation model of slag and iron retention rate in the hearth from step S2 and the calculation model of dead material column volume from step S3, the slag and iron retention rate model is obtained as follows:

[0086] S5, combining the slag iron retention amount model with different blast furnace hearth specifications to obtain a slag iron retention index model: In the formula, V L is the volume of the blast furnace hearth, which is used to evaluate the hearth activity of different blast furnaces; the hearth volume in this embodiment is 160 m 3 ;

[0087] S6, the production parameters of a certain blast furnace in step S1 are respectively brought into the calculation model of the slag iron retention rate of the hearth, the calculation model of the dead material column volume, and the slag iron retention amount and slag iron retention index model, and the obtained structure is shown in the following table.

[0088] Table 2 Calculation results of the slag iron retention amount and the slag iron retention index of a certain blast furnace hearth

[0089] January February March April May Slag-iron retention rate (%) 3.91 6.43 4.77 4.81 5.83 Dead shot volume (m 3 )]]> 123.27 123.33 124.11 129.31 123.84 Slag iron retention (m 3 )]]> 4.82 7.93 5.92 6.22 7.22 Slag-iron retention index (%) 3.01 4.95 3.70 3.89 4.51

[0090] As can be seen from Table 2, this embodiment starts from the essence of slag iron clogging (porous medium model / slag iron flow resistance), uses mathematical theory derivation, introduces slag viscosity and molten iron temperature correction coefficient, and quantitatively calculates the slag iron retention rate. The derivation calculation process shows the scientificity of the present application; for the same blast furnace, the slag iron retention index and the slag iron retention amount trend are consistent, and the slag iron retention amount and the slag iron retention rate trend are consistent. In addition, combined with Table 1 and Table 2, when the blast furnace utilization factor is higher, the coal gas utilization rate is higher, and the fuel ratio is lower, the corresponding slag iron retention index is lower, which conforms to the influence law of hearth activity on the smooth production of blast furnace, further illustrating the scientificity and rationality of the present application. In addition, from Table 2, it can be obtained that the dead material column volume changes relatively small, which is consistent with the actual blast furnace production trend. In the process of blast furnace production, in order to ensure the stable production of blast furnace, the blast parameters and the tapping parameters will not be changed greatly, but due to the fluctuation of the furnace condition at individual moments, the blast / tapping system is forced to be changed, and the dead material column volume will change, which will affect the hearth activity of the blast furnace. The slag iron retention index model of the present application is used to evaluate the hearth activity, which comprehensively considers the influence of the change of the dead material column volume of the blast furnace on the hearth activity of the blast furnace. For different blast furnaces, the slag iron retention index considers the relative relationship between the dead material column volume and the hearth volume, and can directly compare the activity degree of blast furnaces with different furnace capacities, which shows the rationality and comprehensiveness of the slag iron retention index, and the evaluation results of the hearth activity of the blast furnace are more accurate and scientific.

[0091] In actual production of a blast furnace, if the volume of a dead material column of a blast furnace is too large, but the slag-iron temperature is relatively high and the slag-iron retention rate is low; if a traditional slag-iron retention rate evaluation method of furnace hearth activity is used, the low slag-iron retention rate indicates that the blast furnace hearth activity is good; but the blast furnace experts believe that the dead material column is excessively hypertrophic, and the blast furnace hearth is certainly not active, so the evaluation result of the method is obviously unreasonable. It can be seen that the slag-iron retention rate evaluation method of blast furnace hearth activity does not consider the influence of the volume of the dead material column on the activity of the blast furnace hearth, and the accuracy of the evaluation of the activity of the blast furnace hearth is not as good as that of the slag-iron retention index model; the method of evaluating the activity of the blast furnace hearth by the slag-iron retention index model is accurate, reasonable and scientific.

[0092] In summary, the application provides a method for evaluating the activity of a blast furnace hearth by a slag-iron retention index of the blast furnace hearth, which is based on a calculation model of the slag-iron retention rate and the volume of the dead material column, a slag-iron retention amount model is constructed, the slag-iron retention index model is obtained by combining the slag-iron retention amount model with different parameters of the blast furnace hearth, and the activity of the blast furnace hearth of different blast furnaces is evaluated according to the change trend of the slag-iron retention index in actual production of the blast furnace. The slag-iron retention amount of the blast furnace hearth is calculated in the slag-iron retention index model for evaluating the activity of the blast furnace hearth, the contribution degrees of factors influencing the slag-iron retention amount are evaluated by using a multi-factor coupling analysis method, the factors with high correlation are introduced into the slag-iron retention amount model, and then introduced into the slag-iron retention index model, thereby improving the accuracy of the model in evaluating the activity of the blast furnace hearth. The slag-iron retention index model is a relatively comprehensive model integrating the slag-iron composition, the slag-iron temperature, the blast parameter and the tapping parameter, and realizes the rapid and accurate evaluation of the activity of the blast furnace hearth in actual production. The application starts from the actual smelting of the blast furnace, comprehensively considers the influence of various production parameters of the blast furnace on the activity of the blast furnace hearth in actual production, and establishes a scientific and systematic method for evaluating the activity of the blast furnace hearth. When the application is applied to actual production of the blast furnace, the activity of the blast furnace hearth can be timely and accurately reflected, and the significance of guiding the actual production of the blast furnace is achieved.

[0093] The above examples are only used to illustrate the technical solutions of the application but not limit the application. Although the application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the application can be modified or replaced equivalently without departing from the spirit and scope of the technical solutions of the application.

Claims

1. A method for evaluating the activity of a blast furnace hearth by using the slag iron retention index of the hearth, characterized in that, The method comprises the following steps: S1, constructing a slag-iron retention amount model based on a calculation model of a slag-iron retention rate and a dead man volume; the slag iron holdup model: where h is the furnace hearth slag iron holdup, %; V d is the dead man volume, m 3 ; The calculation model of the furnace hearth slag iron retention rate: In the formula, C pm is the capillary number, dimensionless; a is the viscosity correction coefficient, dimensionless; and β is the temperature correction coefficient, dimensionless. The calculation model of the dead man volume: first, calculating the blast furnace tuyere rotation zone length according to the blast parameters, combining the tapping parameters, and obtaining the size parameters required for calculating the dead man volume according to the similar triangle principle, and finally obtaining the calculation model of the dead man volume; S2, the slag iron retention amount model in step S1 is combined with different specifications of the blast furnace hearth to obtain a slag iron retention index model: wherein V L is the volume of the blast furnace hearth; S3, obtaining the change trend of the slag-iron retention index in the actual production of the blast furnace according to the slag-iron retention index model obtained in step S2, so as to evaluate the activity of the hearth of different blast furnaces.

2. The method for evaluating the activity of the hearth of a blast furnace using the slag iron retention index of the hearth of the blast furnace according to claim 1, characterized in that, In step S1, the number of capillaries characterizes the actual slag-iron passage through the coke in the blast furnace, and the formula for calculating it is: In the formula, ρ L The density of blast furnace slag is kg / m³. 3 g is the acceleration due to gravity, in m / s². 2 ; is the coke shape factor, which is dimensionless; d p is the coke diameter in the hearth, m; σ L is the slag surface tension, N / m; θ is the contact angle between the slag and the coke, °; ε is the deadman voidage, dimensionless.

3. The method for evaluating the activity of the hearth of a blast furnace by using the slag-iron retention index of the hearth of the blast furnace according to claim 2, wherein the method for determining the coke diameter of the hearth of the blast furnace comprises the following steps: based on the investigation of the damage of the hearth of the blast furnace and the results of the tuyere coke extraction, introducing the parameters of the CSR, CRI and the coke particle size entering the blast furnace, constructing the relationship between the coke diameter of the hearth of the blast furnace and the coke entering the blast furnace, and obtaining the coke diameter of the hearth of the blast furnace.

4. The method for evaluating the activity of the hearth of a blast furnace using the slag iron retention index of the hearth of the blast furnace according to claim 1, characterized in that, In step S1, the determination of the calculation model of the dead man volume specifically comprises the following steps: SS1, model processing of the dead man, assuming that the dead man of the blast furnace is composed of two parts, showing the shape of a combination of a right circular cone and an inverted circular table; SS2, calculating the dead man tuyere platform radius according to the relationship between the radius of the hearth of the blast furnace and the length of the tuyere rotation zone of the blast furnace, and calculating the circular cone cross-sectional diameter of the dead man in the same plane as the tuyere platform according to the dead man tuyere platform radius; SS3, obtaining the dead man corner angle cross-sectional radius according to the similar triangle principle, and then calculating the distance from the dead man corner to the lower surface of the dead man circular table; SS4. obtaining a computational model of the dead stock volume: wherein r d is the dead plug cone angle cross-sectional radius, m; r dd is the dead plug frustum lower surface radius, m; h dd is the distance from the dead plug corner to the dead plug frustum lower surface, m; h du is the distance from the dead plug upper top to the corner, m.

5. The method for evaluating the activity of the hearth of a blast furnace using the slag iron retention index of the hearth of the blast furnace according to claim 4, characterized in that, In step SS3, the calculation formula of the dead plug cone angle cross section radius is: In the formula, r d is the radius of the dead man hole cone angle section, m; r h is the diameter of the furnace, m; l t is the depth of the taphole, m; h t is the height of the dead man hole above the tuyere, m; h th is the height from the highest position of the dead man hole to the corner of the dead man hole, m; h td is the distance from the taphole plane of the dead man hole to the corner, m.

6. The method for evaluating the activity of the hearth of a blast furnace by using the slag iron retention index of the hearth of the blast furnace according to claim 5, characterized in that, The calculation formula of the distance from the dead column corner to the lower surface of the dead column circular table is h dd = (r d -r dd ) tan θ; In the formula, h dd is the distance from the dead column corner to the lower surface of the dead column circular table, m; r d is the dead column corner, m; θ is the dead column cone angle section radius, m; 7. The method for evaluating the activity of the hearth of a blast furnace by using the slag iron retention index of the hearth of the blast furnace according to claim 1, characterized in that, The viscosity correction coefficient is calculated according to the viscosity of the slag system and the standard viscosity of the slag system under the condition of 1500 DEG C.

8. The method for evaluating the activity of the hearth of a blast furnace by using the slag iron retention index of the hearth of the blast furnace according to claim 1, characterized in that, The temperature correction coefficient is calculated according to the slag melting temperature and the molten iron temperature.

9. The method for evaluating the activity of the hearth of a blast furnace by using the slag iron retention index of the hearth of the blast furnace according to claim 7, characterized in that, The formula for calculating the viscosity of the slag system is: In the formula, μ is the viscosity of the slag system, Pa·s; t is the slag temperature, ℃; E is the kinetic energy of the blast, kg·m / s; A w is the key correlation coefficient, dimensionless.

10. The method for evaluating the activity of the hearth of a blast furnace using the slag iron retention index of the hearth of the blast furnace according to claim 8, characterized in that, The formula for calculating the slag melting temperature: T r = 1204.6 + 5.902-m(Al203)-2.961-m(MgO) + 90.286R; In the formula, m(Al2O3) is the mass content of Al2O3 in the blast furnace slag, wt%; m(MgO) is the mass content of MgO in the blast furnace slag, wt%; R is the alkalinity, dimensionless, which is the mass ratio of CaO to SiO2.

Images