CN115828534A - Method for evaluating hearth activity by using slag iron retention index of blast furnace hearth - Google Patents
Method for evaluating hearth activity by using slag iron retention index of blast furnace hearth Download PDFInfo
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- 229910052742 iron Inorganic materials 0.000 title claims abstract description 155
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- SNAAJJQQZSMGQD-UHFFFAOYSA-N aluminum magnesium Chemical compound [Mg].[Al] SNAAJJQQZSMGQD-UHFFFAOYSA-N 0.000 description 2
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Abstract
The invention provides a method for evaluating the activity of a hearth by applying a slag iron retention index of a blast furnace hearth, which is characterized by constructing a slag iron retention model based on a calculation model of the slag iron retention rate and the volume of a dead charge column of the hearth, and obtaining the slag iron retention index by combining with the parameters of the blast furnace hearth so as to evaluate the activity of the blast furnace hearth. The method utilizes a multi-factor coupling analysis method to evaluate the contribution degree of factors influencing the slag iron retention, constructs a slag iron retention index model integrating slag iron components, slag iron temperature, blast parameters and tapping parameters, and achieves the purpose of scientifically and accurately evaluating the activity of the blast furnace hearth. The invention starts from the actual blast furnace smelting, comprehensively considers the influence of each production parameter of the blast furnace on the hearth activity, establishes a model for scientifically and systematically evaluating the blast furnace hearth activity, can realize the online monitoring of the blast furnace hearth activity change during the actual application, and provides guidance for the production regulation and control of the blast furnace.
Description
Technical Field
The invention relates to the technical field of blast furnace ironmaking, in particular to a method for evaluating hearth activity by using a slag iron retention index of a blast furnace hearth.
Background
As an important component of the steel industry, blast furnace ironmaking bears the burden of the reasonable utilization of resources and the reduction of CO in the whole industry 2 The important role of discharge is that the realization of high yield, high quality, low consumption, long service life and safe production of the blast furnace becomes the trend of the development of the modern blast furnace technology, and the key point is how to keep the good working state of the blast furnace hearth. The working state of the hearth is closely related to the furnace heat state, the gas and liquid permeable state, the blast and the slag iron discharge state, and is the basis of the stable and smooth operation of the blast furnace and the long service life of the hearth.
At present, the method for judging the activity of the hearth in the production of the blast furnace is mainly based on actual production experience and indirectly reflects the active condition of the hearth by means of a characterization index, and has certain hysteresis and theoretical limitation. In addition, the invention patent (application number CN 201910694721. X) discloses a method for quantifying the activity of a blast furnace hearth, which is based on a slag iron flow resistance coefficient f L Constructing a new hearth activity index NHA, and realizing the quantitative characterization of hearth activity; however, the influence of the slag iron parameters is mainly considered in the method, the influence of other factors (such as blast parameters and the like) on the activity of the hearth is not considered, so that the accuracy of the quantitative result is low, and the parameters required by the representation of the method are quite complex and cannot be directly obtained in the blast furnace production, so that the method is difficult to directly apply to the actual blast furnace production.
The invention patent (application number is CN 201810596710.3) discloses a system, a method and a device for detecting activity of a blast furnace hearth. The invention provides a method for representing the activity of a hearth by adopting the retention rate of slag iron, which can represent the potential of the activity of the blast furnace hearth, but does not consider the influence of a lower regulation system of the blast furnace and the dead stock column state of the blast furnace hearth on the activity degree of the hearth, and the accuracy of predicting the activity of the hearth needs to be improved under the condition of the change of the operation system of the blast furnace.
Known from the prior art, the existing evaluation and calculation models about the activity of the blast furnace hearth are not comprehensive enough, and the influence of the actual production condition of the blast furnace, the form and the state of a dead charge column and various production parameters on the activity of the blast furnace hearth is not fully considered in the calculation process; therefore, no method which meets the actual production of the blast furnace and accurately and timely reflects the activity of the hearth exists at present.
In view of the above, there is a need to design an improved method for evaluating the hearth activity by using the slag iron retention index of the blast furnace hearth to solve the above problems.
Disclosure of Invention
The invention aims to provide a method for evaluating the activity of a hearth by using a slag iron retention index of a blast furnace hearth, which is implemented by starting from the actual smelting of the blast furnace, quantitatively analyzing the action proportion of each production parameter of the blast furnace on the activity of the hearth, introducing a parameter with high correlation into a slag iron retention model, obtaining a slag iron retention index model by combining the parameters of the blast furnace hearth, and representing the activity of the blast furnace hearth; a model for scientifically and systematically evaluating the activity of the blast furnace hearth is established, so that when the model is applied to the 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.
In order to achieve the above object, the present invention provides a method for evaluating hearth activity by using a slag iron retention index of a blast furnace hearth, comprising the steps of:
s1, building a slag iron retention model based on a calculation model of slag iron retention rate and dead charge column volume of a furnace hearth;
the slag iron retention model is as follows:
in the formula, h is the slag iron retention rate of the hearth,%; v d Is the dead charge column volume, m 3 ；
The calculation model of the slag iron retention rate of the furnace hearth comprises the following steps:
in the formula C pm Capillary number, dimensionless; alpha is viscosity correction coefficient and is dimensionless; beta is a temperature correction coefficient and is dimensionless.
The calculation model of the dead material column volume is as follows: firstly, calculating the length of a blast furnace tuyere raceway according to blast parameters, obtaining size parameters required for calculating the volume of the dead charge column according to a similar triangle principle by combining tapping parameters, and finally obtaining a calculation model of the volume of the dead charge column;
s2, combining the slag iron retention model in the step S1 with different specifications of a blast furnace hearth to obtain a slag iron retention index model:
in the formula, V L Is the volume of the blast furnace hearth;
and 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 the step S2 so as to evaluate the hearth activity of different blast furnaces.
As a further improvement of the invention, in step S1, the capillary number represents the actual coke penetration process of the blast furnace slag iron, and the calculation formula is as follows:
in the formula, ρ L Is the density of blast furnace slag in kg/m 3 (ii) a g is the acceleration of gravity, m/s 2 ；
Is coke form factor, dimensionless；d p Is the diameter of the coke in the hearth, m; sigma L Is the slag surface tension, N/m; theta is the contact angle between the slag and the coke, degree; epsilon is the void fraction of dead material column, and is dimensionless.
As a further improvement of the invention, the method for determining the diameter of the coke in the hearth comprises the following steps: based on the blast furnace hearth damage investigation and the tuyere coke-taking result, CSR, CRI and the particle size parameters of the coke entering the furnace are introduced, and the relationship between the diameter of the hearth coke and the diameter of the coke entering the furnace is constructed to obtain the diameter of the hearth coke.
As a further improvement of the present invention, in step S1, the determining of the calculation model of the dead charge column volume specifically includes the following steps:
SS1, performing modeling treatment on the dead material column, wherein the dead material column of the blast furnace is supposed to be composed of two parts and takes the combined shape of a right circular cone and an inverted circular truncated cone;
SS2, calculating to obtain the radius of a dead charge column tuyere platform according to the relation between the radius of a blast furnace hearth and the length of a blast furnace tuyere raceway, and calculating to obtain the diameter of a conical section of a dead charge column which is positioned on the same plane with the tuyere platform according to the radius of the dead charge column tuyere platform;
SS3, obtaining the radius of the conical angle section of the dead charge column according to the similar triangular principle, and further calculating the distance from the corner of the dead charge column to the lower surface of the circular truncated cone of the dead charge column;
SS4, obtaining a calculation model of the dead material column volume:
in the formula, r d The radius of the conical angle section of the dead material column is m; r is dd The radius of the lower surface of the truncated cone of the dead material column is m; h is dd The distance m from the corner of the dead material column to the lower surface of the round table of the dead material column; h is du The distance m from the top of the upper part of the dead material column to the corner.
As a further improvement of the present invention, in step SS3, the calculation formula of the conical section radius of the dead charge column is:
in the formula, r d The radius of the conical angle section of the dead material column is m; r is h Is the diameter of the hearth, m; l. the t Is the depth of the taphole, m; h is t The height m of the dead material column above the tuyere is used as the height; h is th M is the height from the highest position of the dead material column to the corner of the dead material column; h is td Is the distance from the plane of the iron notch of the dead material column to the corner, m.
As a further improvement of the present invention, a calculation formula of the distance from the corner of the dead charge column to the lower surface of the circular truncated cone of the dead charge column is as follows: h is a total of dd ＝(r d -r dd )tanθ；
In the formula, h dd The distance m from the corner of the dead material column to the lower surface of the truncated cone of the dead material column is defined; r is d The radius of the conical angle section of the dead material column is m; theta is the dead pillar corner.
As a further improvement of the invention, the viscosity correction coefficient is calculated according to the viscosity of the slag system and the standard viscosity of the slag system at 1500 ℃.
As a further improvement of the present invention, the temperature correction coefficient is calculated from the slag-fusion temperature and the molten iron temperature.
As a further improvement of the present invention, in step S1, the calculation formula of the viscosity of the slag system is:
in the formula, mu is slag viscosity, pa.s; t is the slag temperature, DEG C; e is blast kinetic energy, kg.m/s; a. The w The relative action coefficient is a key and has no dimension.
As a further improvement of the present invention, the calculation formula of the slag meltability temperature is: t is r ＝1204.6+5.902·m(Al 2 O 3 )-2.961·m(MgO)+90.286R；
In the formula, m (Al) 2 O 3 ) Is Al in blast furnace slag 2 O 3 Mass content of (1), wt%; m (MgO) is the weight percent of MgO in the blast furnace slag; r is alkalinity, dimensionless, caO and SiO 2 The mass ratio of (a).
The invention has the beneficial effects that:
1. the invention discloses a method for evaluating hearth activity by using a slag iron retention index of a blast furnace hearth, which is characterized in that a slag iron retention model is constructed based on a calculation model of the slag iron retention rate of the hearth and the volume of a dead charge column, and the slag iron retention index is obtained by combining the slag iron retention model with different sizes of the blast furnace hearth, so that the hearth activity of different blast furnaces is evaluated. The slag iron retention of the furnace hearth is calculated in the slag iron retention index model, the factors influencing the slag iron retention are subjected to contribution degree evaluation by using a multi-factor coupling analysis method, and the factors with high relevance are introduced into the slag iron retention model, so that the model accuracy is improved. The invention starts from the actual blast furnace smelting, comprehensively considers the influence of each production parameter of the blast furnace on the hearth activity in the actual production, establishes a model for scientifically and systematically evaluating the blast furnace hearth activity, can timely and accurately reflect the blast furnace hearth activity when being applied to the actual production of the blast furnace, and plays a role in guiding the actual production of the blast furnace.
2. When a calculation model of the slag iron retention rate is established, the retention rate is corrected from two aspects of slag chemical stability and thermal stability, so that the slag iron retention rate is more consistent with the actual production of a blast furnace; in the calculation of the number of the capillary tubes representing the parameter of the actual slag iron coke penetration process of the blast furnace, a hearth coke granularity calculation method is introduced, and compared with the traditional method adopting the hearth coke granularity, the accuracy of the hearth coke granularity is higher. When a calculation model of the volume of the dead charge column is established, the size of the dead charge column is related to the size of a blast furnace tuyere raceway, the depth of a taphole and design parameters of the blast furnace, so blast parameters and tapping parameters are introduced, and the calculated size of the volume of the dead charge column is more in line with the actual production of the blast furnace. Therefore, the slag iron retention index model for evaluating the activity of the blast furnace hearth is a relatively comprehensive model integrating slag iron components, slag iron temperature, blast parameters and tapping parameters, and realizes the rapid and accurate evaluation of the activity of the blast furnace hearth in actual production.
3. The calculation parameters in the slag iron retention index model are all 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 parameters are input in real time, the activity of the hearth of the blast furnace is monitored and predicted in real time, the model is also suitable for the production of the blast furnaces with different specifications, and the practicability and universality are high. In addition, the quantitative influence relation of each parameter on the slag iron retention/hearth activity is given out in the model, and theoretical guidance is provided for the blast furnace production workers to regulate and control the hearth activity in actual production. Compared with a hearth activity evaluation model which has the advantages of large limitation, incomplete parameter consideration and large influence by the fluctuation of the blast furnace condition in the prior art, the slag iron retention index model for evaluating the activity of the blast furnace hearth has the advantages of high accuracy, good instantaneity and stable result.
Drawings
FIG. 1 is a schematic flow chart of a method for evaluating hearth activity by using a slag iron retention index of a blast furnace hearth according to the present invention.
FIG. 2 is a result graph of the influence contribution degree of each factor on the slag iron retention rate calculation model.
FIG. 3 is a result diagram of influence contribution of various factors on a dead material column volume calculation model.
FIG. 4 is a schematic structural diagram of a dead material column, wherein (a) is a schematic structural diagram of a dead material column of a blast furnace, and (b) is a schematic geometric structural diagram of the dead material column in the diagram (a).
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in detail with reference to the accompanying drawings and specific embodiments.
It should be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and/or processing steps closely related to the aspects of the present invention are shown in the drawings, and other details not closely related to the present invention are omitted.
In addition, it is also to be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
Referring to fig. 1, the present invention provides a method for evaluating hearth activity using a slag iron retention index of a blast furnace hearth, comprising the steps of:
s1, building a slag iron retention model based on a calculation model of slag iron retention rate and dead charge column volume of a furnace hearth;
s2, combining the slag iron retention model in the step S1 with different specifications of the blast furnace hearth to obtain a slag iron retention index model:
in the formula, V L Is the volume of the blast furnace hearth;
and 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 the step S2 so as to evaluate the hearth activity of different blast furnaces.
Specifically, in step S1, the slag iron retention model:
wherein h is the slag iron retention (%) of the hearth, and V d Is dead material column volume (m) 3 )；
A calculation model of slag iron retention rate of the furnace hearth:
in the formula, C pm Capillary number, dimensionless; alpha is viscosity correction coefficient and is dimensionless; beta is a temperature correction coefficient and is dimensionless. The viscosity correction coefficient alpha is determined according to the slag system viscosity mu and the slag system standard viscosity mu under the condition of 1500 DEG C 0 Calculating to obtain; the temperature correction coefficient beta is based on the slag melting temperature T r And the temperature T of the molten iron is obtained by calculation.
Calculation model of dead charge column volume: firstly, calculating the length of a blast furnace tuyere raceway according to blast parameters, obtaining size parameters required for calculating the volume of a dead charge column by combining tapping parameters and according to a similar triangle principle, and finally obtaining a calculation model of the volume of the dead charge column.
Specifically, the calculation formula of the viscosity of the slag system is as follows:
wherein μ is a slag viscosity (Pa · s), t is a slag temperature (DEG C), E is a blast kinetic energy (kg · m/s), A w The relative action coefficient is a key and has no dimension. In some embodiments, μ is CaO-SiO 2 -Al 2 O 3 Viscosity of-MgO Quaternary slag System for CaO-SiO 2 -Al 2 O 3 In a-MgO quaternary slag system, the slag system,
in the formula, A 1 、A 2 、A 3 、A 4 、A 5 、A 6 、A 7 Respectively are the relevant action coefficients of Si-O-Si, si-O-Al, si-O-Ca, al-O-Ca, si-O-Mg, al-O-Mg and Al-O-Al;
the calculation formula of the slag meltability temperature is as follows: t is r ＝1204.6+5.902·m(Al 2 O 3 ) -2.961. M (MgO) +90.286R, in which T r The slag melting temperature (. Degree. C.), m (Al) 2 O 3 ) Is Al in blast furnace slag 2 O 3 M (MgO) is the weight content (wt%) of MgO in the blast furnace slag; r is alkalinity (dimensionless) and is CaO and SiO 2 The mass ratio of (a).
Referring to fig. 2, the influence factors of the slag-iron retention rate mainly include slag parameters, coke parameters, molten iron temperature (T), dead charge column porosity (epsilon), and the like, and the influence factors are subjected to weight analysis to obtain specific parameters including slag basicity, slag magnesium-aluminum ratio, coke particle size, coke CRI, coke CSR, molten iron temperature, slag titanium content, and permeability index. And (3) researching the relation between the slag iron retention rate and the factors by combining with the actual production data of the blast furnace, quantitatively determining the influence contribution degree of the factors on the slag iron retention rate, and obtaining a result graph of the contribution degree of each factor on the slag iron retention rate in the graph 1. As can be seen from the figure, the contribution degree sequence of the above factors is: the contribution degree of the molten iron temperature is 35%, the contribution degree of the CSR is 26%, the contribution degree of the coke granularity is 13%, the contribution degree of the CRI is 12%, the contribution degree of the slag alkalinity is 8%, the contribution degree of the slag magnesium-aluminum ratio is 5%, and the contribution degree of the slag titanium content is 1%.
Therefore, when a calculation model of the slag iron retention rate is established, the retention rate is corrected from two aspects of slag chemical stability and thermal stability, and a slag fluidity correction factor (namely a viscosity correction factor alpha) and a temperature correction factor (namely a temperature correction factor beta) are introduced to make the retention rate more accord with the actual production of the blast furnace; in the calculation of the number of the capillary tubes representing the actual slag iron coke penetration process of the blast furnace, the coke granularity, CSR and CRI can be changed in the process of the blast furnace coke from the inlet to the tuyere due to the complex environment of the blast furnace, and the accuracy of the coke granularity in the inlet of the blast furnace adopted in the traditional method is poor; therefore, the method introduces the representation of the hearth coke granularity, replaces the furnace-entering coke granularity by the hearth coke granularity, eliminates the influence of the actual production process of the blast furnace on the furnace-entering coke granularity, and greatly improves the accuracy of the slag iron retention rate model.
Specifically, the slag fluidity is influenced by the slag composition, the slag density, the slag surface tension, the slag viscosity and the slag meltability temperature, so that the calculation formula of the capillary number for representing the actual coke penetration process of the blast furnace slag iron is
In the formula, ρ L Is the blast furnace slag density (kg/m) 3 ) G is the acceleration of gravity (generally 9.8 m/s) 2 )，
Is coke form factor (dimensionless), d p Is the diameter (m), sigma, of coke in the hearth L Is the surface tension (N/m) of the slag, theta is the contact angle between the slag and the coke (generally taking the value of 120 degrees), and epsilon is the void degree of a dead material column;
wherein the diameter d of coke in the hearth p The determination method comprises the following steps: based on the blast furnace hearth damage investigation and the tuyere coke-taking result, CSR, CRI and the particle size parameters of the coke entering the furnace are introduced, and the relationship between the diameter of the hearth coke and the diameter of the coke entering the furnace is constructed to obtain the diameter of the hearth coke. Because the coke granularity of the hearth is influenced by the burning loss of the high-temperature action of the tuyere raceway and the gasification reaction degree of the upper part of the blast furnace, CS is introducedR, CRI and the granularity parameter of the coke entering the furnace, so that the diameter result of the coke in the hearth obtained by calculation is more accurate;
the blast furnace slag density calculation formula is as follows: rho t ＝∑X MO ·ρ MO In the formula, rho L Is the density (kg/m) of blast furnace slag 3 )，X MO Is the molar ratio (%) of each component, rho MO For the density (kg/m) of each component 3 )；
The calculation formula of the slag surface tension is as follows: sigma l ＝∑X MO ·σ MO In the formula σ L Is the slag surface tension (N/m), X MO Is the molar ratio (%) of each component, sigma MO The surface tension (N/m) of each component was used.
Referring to fig. 3, by evaluating the contribution degrees of factors (air volume, oxygen volume, air temperature, air pressure, and coal injection volume) affecting the retention amount of slag iron in the blast furnace hearth, and combining with actual data of blast furnace production, the contribution degrees of the above factors are assigned according to the statistical principle, and the obtained result is: the air volume contribution degree is 31%, the taphole depth is 26%, the air temperature contribution degree is 18%, the air pressure contribution degree is 16%, the coal injection volume contribution degree is 6%, the oxygen volume contribution degree is 3%, and the correlation ranking with the slag-iron retention model is obtained as follows: the air quantity is larger than the iron notch depth, the air temperature is larger than the air pressure, the coal injection quantity is larger than the oxygen quantity; therefore, the blast parameters and the tapping parameters are introduced into the calculation model of the dead charge column volume and further introduced into the slag iron retention model so as to improve the accuracy of the slag iron retention index model in quantifying the activity of the blast furnace hearth.
Specifically, the determination of the calculation model of the dead material column volume comprises the following steps:
SS1, performing modeling treatment on the dead material column, wherein the dead material column of the blast furnace is supposed to be composed of two parts and takes the combined shape of a right circular cone and an inverted circular truncated cone; specifically, the irregular shape of the upper dead charge column in the blast furnace is similar to an ideal right circular cone, the irregular shape of the lower dead charge column is similar to an ideal inverted round table, and the corner of the dead charge column is 30-40 degrees, as shown in figure 4;
SS2, calculating to obtain the radius of a dead charge column tuyere platform according to the relation between the radius of a blast furnace hearth and the length of a blast furnace tuyere raceway, and calculating to obtain the diameter of a conical section of a dead charge column on the same plane with the tuyere platform according to the radius of the dead charge column tuyere platform;
SS3, as shown in figure 4, two groups of similar triangles exist in the positive cone-shaped dead charge column, namely, the dead charge column is above the tuyere plane, above the iron notch plane and above the dead charge column cone angle; according to the similar triangle principle, the radius of the conical angle section of the dead charge column is obtained, and then the distance from the corner of the dead charge column to the lower surface of the round table of the dead charge column is calculated;
SS4, obtaining a calculation model of the volume of the dead material column:
in the formula, r d Is the radius (m), r of the taper angle section of the dead material column dd The radius (m), h) of the lower surface of the round table of the dead material column dd The distance (m, h) from the corner of the dead material column to the lower surface of the round table of the dead material column du The distance (m) from the top of the upper part of the dead material column to the corner.
In the step SS3, a calculation formula of the taper angle section radius of the dead material column is as follows:
in the formula, r d Is the radius (m), r of the taper angle section of the dead material column h Is the diameter (m) of the hearth t Is the depth (m), h of the taphole t The height (m), h) of the dead material column above the tuyere th Is the height (m), h) from the highest position of the dead material column to the corner of the dead material column td The distance (m) from the plane of the iron notch of the dead material column to the corner;
the calculation formula of the distance from the corner of the dead material column to the lower surface of the round table of the dead material column is as follows: h is dd ＝(r d -r dd ) tan θ. In the formula, h dd The distance (m) from the corner of the dead material column to the lower surface of the round table of the dead material column d The radius (m) of the conical angle section of the dead material column; theta is a corner of the dead material column; in some specific embodiments, the dead pillar corner θ is 35 °.
In the step SS2, the calculation formula of the length of the tuyere convolution area of the blast furnace is as follows:
in the formula, D R Is the length (m) of the tuyere raceway, E is the blast kinetic energy (kg. M/s), P c The coal injection amount (kg/h) is adopted, and n is the number (number) of tuyeres;
wherein, the blast kinetic energy computational formula is:
the formula for calculating mass is:
the velocity is calculated by
In the above formula, V B The blast furnace is supplied with air (m) into the furnace 3 /min)，V O2 Is the total oxygen amount (m) 3 /min)，V' O2 The total oxygen content (m) of the oxygen-enriched air added after deducting the hygrometer from the total oxygen content 3 /min)，S f Is the area of the tuyere (m) 2 )，T B Is the temperature (K) of hot air, P B Hot air pressure (kPa), W B For blast humidity (kg/m) 3 ) N is the number of air ports P 0 Is a standard state pressure (K), T 0 Is a standard state temperature (kPa).
From the foregoing, the calculation parameters in the slag iron retention index model of the invention are all report parameters of the actual production of the blast furnace, so that the slag iron retention index model can be directly used in the actual production of the blast furnace, can input the parameters in real time, can monitor and predict the activity of the hearth of the blast furnace in real time, and has high practicability and universality; the model can be directly applied to different blast furnace production lines, can accurately reflect the activity of the blast furnace hearth in time, and plays a role in guiding the actual production of the blast furnace.
Example 1
The embodiment provides a method for evaluating the hearth activity by using the slag iron retention index of a blast furnace hearth, and the method is combined with the actual production of the blast furnace, and comprises the following steps:
s1, sorting numerical values required by calculation of slag iron retention of a blast furnace hearth, and collecting data parameters of a certain blast furnace for 1-5 months as shown in a table 1;
TABLE 1 actual blast furnace production parameters
| 1 month | 2 month | 3 month | 4 month | Month 5 | |
| Alkalinity of | 1.15 | 1.16 | 1.15 | 1.15 | 1.17 |
| Ratio of magnesium to aluminum | 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 |
| Temperature of molten iron (. Degree. C.) | 1508.00 | 1505.00 | 1507.00 | 1506.00 | 1506.00 |
| Gas utilization (%) | 43.57 | 41.85 | 43.20 | 42.59 | 42.26 |
| Using coefficient (t/d/m) 3 ) | 4.06 | 3.91 | 3.99 | 4.033 | 4.02 |
| Blast volume (m) 3 /min) | 2827.00 | 2822.00 | 2811.00 | 2823.00 | 2828.00 |
| Blast temperature (. Degree.C.) | 1184.00 | 1200.00 | 1204.00 | 1204.00 | 1204.00 |
| Blast 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 amount (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 |
S2, establishing a calculation model of the slag iron retention rate of the hearth:
alpha is a viscosity correction coefficient and is obtained by calculation according to the viscosity mu of the slag system and the standard viscosity of the slag system at 1500 ℃; beta is a temperature correction coefficient according to the slag melting temperature T r And measuring the molten iron temperature;
wherein,
T r ＝1204.6+5.902·m(Al 2 O 3 )-2.961·m(MgO)+90.286R；
in the calculation of the diameter of the coke in the hearth, the diameter d of the coke to be charged is calculated 0 The calculation method comprises the following steps: sieving the coke, and classifying the coke into particles with the particle sizes of less than 10mm, 10-20 mm, 20-30 mm, 30-40 mm,Six granularity levels of 40-50 mm and more than 50mm, and the mass ratio of each granularity level is C 1 、C 2 、C 3 、C 4 、C 5 And C 6 Multiplying the median value of each interval by the mass ratio of each interval (the granularity of less than 10mm is 5mm, the granularity of more than 50mm is 55 mm), and calculating the average granularity of the coke; the specific calculation formula is
d 0 The granularity (m) of coke charged into the furnace, i is a serial number and the numerical value is 1-6;
s3, establishing a calculation model of the volume of the dead material column:
in the formula, r d Is the radius (m), r of the taper angle section of the dead material column dd The radius (m), h) of the lower surface of the round table of the dead material column dd The distance (m, h) from the corner of the dead material column to the lower surface of the round table of the dead material column du The distance (m) from the top of the upper part of the dead material column to the corner; wherein,
h dd ＝(r d -r dd )tanθ；
as shown in FIG. 4, the dimensional parameters in the above formula can be derived according to the principle of similar triangles, where r t Obtained by the diameter of the furnace hearth-the depth of a rotating area of the tuyere of the blast furnace-0.5, and the length of the rotating area of the tuyere of the blast furnace is calculated by the formula
In the formula,
the formula for calculating mass is:
the velocity is calculated as:
s4, obtaining a slag iron retention model according to the calculation model of the slag iron retention rate of the furnace hearth in the step S2 and the calculation model of the dead charge column volume in the step S3
S5, combining the slag iron retention model with different specifications of the blast furnace hearth to obtain a slag iron retention index model:
in the formula, V L The volume of the blast furnace hearth is used for evaluating the hearth activity of different blast furnaces; the hearth of this example had a volume of 160m 3 ；
And S6, respectively substituting the production parameters of the blast furnace in the step S1 into a slag iron retention rate calculation model, a dead charge column volume calculation model, a slag iron retention amount model and a slag iron retention index model of the furnace hearth, and obtaining the structure shown in the following table.
TABLE 2 calculation results of the slag iron retention and slag iron retention index of a certain blast furnace hearth
| 1 month | Month 2 | 3 month | 4 month | Month 5 | |
| Slag iron retention (%) | 3.91 | 6.43 | 4.77 | 4.81 | 5.83 |
| Dead column 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 |
As can be seen from table 2, in this example, based on the nature of coke penetration of the slag iron (porous medium model/slag iron flow resistance), a mathematical theory is used for derivation, the slag viscosity and the molten iron temperature correction coefficient are introduced, the slag iron retention rate is quantitatively calculated, and the derivation calculation process shows the scientificity of the invention; for the same blast furnace, the slag iron retention index and the slag iron retention trend are consistent, the slag iron retention and the slag iron retention rate trend are consistent, and in addition, in combination with the table 1 and the table 2, when the blast furnace utilization coefficient is higher, the coal gas utilization rate is higher, and the fuel ratio is lower, the corresponding slag iron retention index is lower, the influence rule of the hearth activity on the blast furnace production is met, and the scientificity and the rationality of the method are further explained. In addition, as can be seen from table 2, the volume change of the dead charge column is relatively small, which is consistent with the actual production trend of the blast furnace, in order to ensure the stable production of the blast furnace, the changes of the blast parameters and the tapping parameters cannot be changed too much in the production process of the blast furnace, but the volume of the dead charge column changes due to the fact that the blast/tapping system is forced to be changed at individual moments due to the fluctuation of furnace conditions, and the change of the dead charge column affects the activity of a hearth of the blast furnace; the slag iron retention index model is used for evaluating the hearth activity, and the influence of the volume change of the dead material column of the blast furnace on the blast furnace hearth activity is comprehensively considered; for different blast furnaces, the slag iron retention index takes the relative relation between the volume of the dead charge column and the volume of the hearth into consideration, the blast furnace activity degrees of different furnace volumes can be directly compared, the rationality and the comprehensiveness of the slag iron retention index are shown, and the evaluation result of the blast furnace hearth activity is more accurate and scientific.
In the actual production of the blast furnace, if the volume of a dead material column of a certain blast furnace is too large, the retention rate of the iron slag is low because the temperature of the iron slag is relatively high; if the traditional method for evaluating the hearth activity by the slag iron retention rate is adopted, the low slag iron retention rate indicates that the blast furnace hearth activity is better; however, the evaluation results of this method are clearly not reasonable, since blast furnace experts consider the dead charge column to be excessively large and their blast furnace shaft must be inactive. Therefore, the influence of the volume of the dead charge column on the activity of the hearth is not considered in the mode of evaluating the activity of the blast furnace hearth by the slag iron retention rate, and the evaluation accuracy of the activity of the hearth is not as good as that of the slag iron retention index model; the method for evaluating the activity of the hearth by using the slag iron retention index model has accuracy, reasonability and scientificity.
In conclusion, the invention provides a method for evaluating the hearth activity by using the slag iron retention index of a blast furnace hearth, which is based on a calculation model of the slag iron retention rate of the hearth and the volume of a dead charge column, constructs a slag iron retention model, obtains the slag iron retention index model by combining the slag iron retention model with different parameters of the blast furnace hearth, and evaluates the hearth activity of different blast furnaces according to the variation trend of the slag iron retention index in the actual production of the blast furnace. The slag iron retention of the hearth is calculated in a slag iron retention index model for evaluating the activity of the blast furnace hearth, the factors influencing the slag iron retention are evaluated by using a multi-factor coupling analysis method, the factors with high correlation are introduced into the slag iron retention model and then introduced into the slag iron retention index model, and the accuracy of the model for evaluating the activity of the blast furnace hearth is improved; the slag iron retention index model is a relatively comprehensive model integrating slag iron components, slag iron temperature, blast parameters and tapping parameters, and realizes rapid and accurate evaluation of the activity of a blast furnace hearth in actual production. The invention starts from the actual blast furnace smelting, comprehensively considers the influence of each production parameter of the blast furnace on the hearth activity in the actual production, establishes a method for scientifically and systematically evaluating the blast furnace hearth activity, can timely and accurately reflect the blast furnace hearth activity when being applied to the actual production of the blast furnace, and plays a role in guiding the actual production of the blast furnace.
Although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the spirit and scope of the present invention.
Claims (10)
1. A method for evaluating the hearth activity by using the slag iron retention index of a blast furnace hearth is characterized by comprising the following steps:
s1, building a slag iron retention model based on a calculation model of slag iron retention rate and dead charge column volume of a furnace hearth;
the slag iron retention model is as follows:
in the formula, h is the slag iron retention rate of the hearth,%; v d Is the dead charge column volume, m 3 ；
The calculation model of the slag iron retention rate of the furnace hearth comprises the following steps:
in the formula, C pm Capillary number, dimensionless; alpha is viscosity correction coefficient and is dimensionless; beta is a temperature correction coefficient and is dimensionless.
The calculation model of the dead material column volume is as follows: firstly, calculating the length of a blast furnace tuyere raceway according to blast parameters, obtaining size parameters required for calculating the volume of the dead charge column according to a similar triangle principle by combining tapping parameters, and finally obtaining a calculation model of the volume of the dead charge column;
s2, combining the slag iron retention model in the step S1 with different specifications of a blast furnace hearth to obtain a slag iron retention index model:
in the formula, V L Is the volume of the blast furnace hearth;
and 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 the step S2 so as to evaluate the hearth activity of different blast furnaces.
2. The method for evaluating the hearth activity by using the slag iron retention index of the blast furnace hearth according to the claim 1, wherein in the step S1, the capillary number represents the actual slag iron coke penetration process of the blast furnace, and the calculation formula is as follows:
in the formula, ρ L Is the density of blast furnace slag in kg/m 3 (ii) a g is the acceleration of gravity, m/s 2 ；
Is coke form factor, dimensionless; d p Is the diameter of the coke in the hearth, m; sigma L Is the slag surface tension, N/m; theta is the contact angle between the slag and the coke, degree; epsilon is the void content of the dead material column and is dimensionless.
3. The method for evaluating the hearth activity by using the slag iron retention index of the blast furnace hearth according to claim 2, wherein the diameter of the hearth coke is determined by the following method: based on the blast furnace hearth damage investigation and the tuyere coke-taking result, CSR, CRI and the particle size parameters of the coke entering the furnace are introduced, and the relationship between the diameter of the hearth coke and the diameter of the coke entering the furnace is constructed to obtain the diameter of the hearth coke.
4. The method for evaluating the hearth activity by using the slag iron retention index of the blast furnace hearth according to the claim 1, wherein in the step S1, the determination of the calculation model of the dead charge column volume specifically comprises the following steps:
SS1, modeling the dead material column, and assuming that the blast furnace dead material column consists of two parts and takes the shape of a combination of a right circular cone and an inverted circular truncated cone;
SS2, calculating to obtain the radius of a dead charge column tuyere platform according to the relation between the radius of a blast furnace hearth and the length of a blast furnace tuyere raceway, and calculating to obtain the diameter of a conical section of a dead charge column which is positioned on the same plane with the tuyere platform according to the radius of the dead charge column tuyere platform;
SS3, obtaining the radius of the conical angle section of the dead charge column according to the similar triangle principle, and further calculating the distance from the corner of the dead charge column to the lower surface of the circular truncated cone of the dead charge column;
SS4, obtaining a calculation model of the dead material column volume:
in the formula, r d Is the radius of the conical angle section of the dead material column, m; r is dd The radius of the lower surface of the truncated cone of the dead material column is m; h is dd The distance m from the corner of the dead material column to the lower surface of the round table of the dead material column; h is du The distance m from the top of the upper part of the dead material column to the corner.
5. The method for evaluating the hearth activity using the slag iron retention index of the blast furnace hearth according to claim 4, wherein in the stepIn SS3, the calculation formula of the taper angle section radius of the dead material column is as follows:
in the formula, r d The radius of the conical angle section of the dead material column is m; r is h Is the diameter of the hearth, m; l. the t Is the depth of the taphole, m; h is t The height m of the dead material column above the tuyere is used as the height; h is a total of th M is the height from the highest position of the dead material column to the corner of the dead material column; h is td The distance m from the plane of the iron notch of the dead material column to the corner.
6. The method for evaluating the activity of the hearth according to the slag iron retention index of the blast furnace hearth of claim 5, wherein the calculation formula of the distance from the corner of the dead charge column to the lower surface of the circular truncated cone of the dead charge column is as follows: h is dd ＝(r d -r dd )tanθ；
In the formula, h dd The distance m from the corner of the dead material column to the lower surface of the round table of the dead material column is defined; r is d The radius of the conical angle section of the dead material column is m; theta is the dead pillar corner.
7. The method for evaluating the hearth activity by using the slag iron retention index of the blast furnace hearth according to the claim 1, wherein the viscosity correction coefficient is calculated according to the viscosity of the slag system and the standard viscosity of the slag system at 1500 ℃.
8. The method for evaluating the hearth activity using the slag iron retention index of the blast furnace hearth according to claim 1, wherein the temperature correction coefficient is calculated from a slag meltability temperature and a molten iron temperature.
9. The method for evaluating the hearth activity by using the slag iron retention index of the blast furnace hearth according to the claim 7, wherein the calculation formula of the viscosity of the slag system is as follows:
in the formula, mu is slag viscosity, pa.s; t is the slag temperature, DEG C; e is blast kinetic energy, kg.m/s; a. The w The relative action coefficient is a key and has no dimension.
10. The method for evaluating the hearth activity using the slag iron retention index of the blast furnace hearth according to claim 8, wherein the calculation formula of the slag meltability temperature is: t is r ＝1204.6+5.902·m(Al 2 O 3 )-2.961·m(MgO)+90.286R；
In the formula, m (Al) 2 O 3 ) Is Al in blast furnace slag 2 O 3 Mass content of (1), wt%; m (MgO) is the weight percent of MgO in the blast furnace slag; r is alkalinity, dimensionless, caO and SiO 2 The mass ratio of (a).
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| CN117233043B (en) * | 2023-11-10 | 2024-02-02 | 北京科技大学 | Method for determining cooperative wetting behavior of iron-slag on surface of carbonaceous material and application of method |
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