CN115563748A - Method for establishing furnace hearth carbon brick erosion degree visualization - Google Patents

Method for establishing furnace hearth carbon brick erosion degree visualization Download PDF

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CN115563748A
CN115563748A CN202211093983.9A CN202211093983A CN115563748A CN 115563748 A CN115563748 A CN 115563748A CN 202211093983 A CN202211093983 A CN 202211093983A CN 115563748 A CN115563748 A CN 115563748A
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hearth
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王炜
陈世锦
陈绪亨
王斌
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Wuhan University of Science and Engineering WUSE
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Abstract

The invention discloses a method for establishing a furnace hearth carbon brick erosion degree visualization, which comprises the steps of firstly, obtaining a carbon brick heat conductivity coefficient-temperature linear relation of a complete layer by utilizing furnace start-up period data; and then, carrying out regional division on the carbon brick according to the erosion change of the carbon brick, calculating to obtain the boundary temperature of the intact layer and the brittle layer by utilizing a thermal conductivity-temperature linear relation and combining the principle of equal heat flux, and carrying out calculation and visual establishment on the residual thickness of the furnace hearth carbon brick based on the boundary temperature and the thermal conductivity of the brittle layer and the iron-infiltrated layer. The method is based on the relation that the thermal conductivity coefficient of the intact layer of the residual carbon bricks changes along with the temperature and the structural change of the carbon bricks after being actually corroded, the obtained result can more accurately reflect the degree of corrosion of the carbon bricks, and the calculation result is visually displayed, so that measures beneficial to safety of the hearth can be guided, the risk of burning-through of the hearth can be reduced, a scientific theoretical basis is provided for prolonging the service life of the blast furnace, and the method has a wide application prospect.

Description

Method for establishing furnace hearth carbon brick erosion degree visualization
Technical Field
The invention relates to the technical field of blast furnace smelting, in particular to a furnace hearth carbon brick erosion degree visualization establishing method.
Background
With the development of iron-making technology, the blast furnace in China makes a significant breakthrough in the technologies of greenization, high efficiency, long service life and the like. For a long time, the hearth is a limiting important link for limiting the long service life of the blast furnace, and the residual thickness of the carbon bricks is a main mode for evaluating the service life of the hearth. Because the interior of the blast furnace has the characteristic of a black box, the carbon brick of the furnace hearth cannot be intuitively measured, the temperature of the carbon brick is often measured by embedding a thermocouple in the carbon brick, and then the residual thickness of the carbon brick is calculated according to the Fourier heat conduction law, so that the purpose of monitoring the erosion degree of the carbon brick of the furnace hearth is achieved.
In the prior art, a patent with publication number CN 114896546A discloses a high-precision calculation method for residual thickness of carbon bricks in a blast furnace hearth, which includes selecting boundary conditions, substituting the thermal conductivity of the carbon bricks into a heat transfer formula in a temperature function form, and further calculating the position of an erosion line and the erosion degree at the final stage of the service of the blast furnace.
In view of the above, it is necessary to design a method for establishing a visualization of the degree of erosion of the hearth carbon bricks to solve the above problems.
Disclosure of Invention
The invention aims to provide a furnace hearth carbon brick erosion degree visualization establishing method which utilizes a linear relation between the heat conductivity coefficient and the temperature of a carbon brick of a complete layer established in a furnace starting period, calculates and obtains the boundary temperature of the complete layer and an embrittled layer of the carbon brick in the later period of a furnace service through the principle of equal heat flux, corrects the important characteristic that the heat conductivity coefficient of the complete layer of the carbon brick changes along with the temperature, calculates and obtains the thickness of the complete layer of the carbon brick based on the boundary temperature, divides the carbon brick into the complete layer, an embrittled layer and an iron-infiltrated layer along the radial direction of a furnace hearth according to the erosion change of the carbon brick, calculates the thicknesses of the embrittled layer and the iron-infiltrated layer of the carbon brick by utilizing the heat conductivity coefficients of the embrittled layer and the iron-infiltrated layer and accurately and visually reflects the erosion degree of the carbon brick.
In order to achieve the purpose, the invention provides a method for establishing the furnace hearth carbon brick erosion degree visualization, which comprises the following steps:
s1, collecting hearth thermocouple arrangement positions and temperature data of a blast furnace in a blow-in period and a non-blow-in period, recording the thermocouple temperature in the blow-in period as Tf, recording the insertion depth of the thermocouple close to the center of the blast furnace as H3, and preprocessing the temperature data of the thermocouple in the blow-in period and the non-blow-in period;
s2, obtaining a thermal conductivity-temperature linear relation formula of the good carbon brick layer based on the principle that the radial heat fluxes of the blast furnace hearth are equal and combined with the thermal power even data in the furnace opening period;
s3, dividing the furnace hearth residual carbon brick into a complete layer, an embrittlement layer and an iron-infiltrated layer along the radial direction of the furnace hearth, recording the thicknesses of the layers in all regions as L1, L2 and L3 respectively, obtaining heat conductivity coefficients lambda 2 and lambda 3 of the embrittlement layer and the iron-infiltrated layer, judging the size relation between the complete layer thickness L1 and the thermocouple insertion depth H3 close to the center of the blast furnace through coupling calculation, and calculating the boundary temperature T0 of the complete layer and the embrittlement layer and the complete layer thickness L1 under different conditions according to the judgment result and by using the heat conductivity-temperature linear relation in the step S2;
s4, calculating the thickness L2 of the embrittlement layer and the thickness L3 of the iron-cementation layer by taking 1150 ℃ as a hot surface temperature critical point of a hearth and 907 ℃ as a boundary temperature point of the embrittlement layer and the iron-cementation layer and combining with the temperature of a real-time thermocouple;
and S5, repeating the steps S1-S4, calculating the lengths L1, L2 and L3 of the intact carbon brick layer, the embrittlement layer and the iron infiltration layer at different heights h of the hearth, and adopting an interpolation algorithm to continuously disperse points to obtain a visual furnace hearth carbon brick erosion degree graph.
As a further improvement of the present invention, in step S1, at least three thermocouples 1, 2, and 3 with different insertion depths are respectively disposed in the hearth, a calculation starting point of the insertion depth is calculated from a starting point of the carbon brick in a direction approaching to the furnace shell, the insertion depths are H1, H2, and H3, respectively, H1< H2< H3, and temperature data of the thermocouples 1, 2, and 3 during the furnace opening period are Tf1, tf2, and Tf3, respectively; the temperature data of the thermocouples 1, 2 and 3 in the non-blow-in period are respectively T1, T2 and T3; the thermocouple temperature data preprocessing comprises the step of eliminating data with the temperature not conforming to T3> T2> T1 and Tf3> Tf2> Tf 1.
As a further improvement of the present invention, in step S2, the thermal conductivity-temperature linear relation of the intact carbon brick layer is as follows:
λ＝f(t)＝λ c +b(t-t c )
b＝2λ c [(H2-H1)(Tf3-Tf2)-(H3-H2)(Tf2-Tf1)]×[(H3-H2)(Tf2-Tf1)(Tf2+Tf1-2tc)-(H2-H1)(Tf3-Tf2)(Tf3+Tf2-2tc)] -1
wherein λ is c Is a temperature t c The thermal conductivity coefficient of the lower carbon brick in factory detection, and b is a temperature coefficient.
As a further improvement of the present invention, in step S3, the coupling calculation is to calculate a heat flux difference value c between the thermocouples 1 and 2 and the thermocouples 2 and 3 to determine a relationship between the thicknesses L1 and H3 of the intact layer.
As a further improvement of the present invention, if c is greater than the preset difference value a, L1 is considered to be < H3; if c is smaller than the preset difference value a, considering that L1 is larger than H3; the calculation formula of the heat flux difference value c is as follows:
Figure BDA0003838174660000031
wherein q is 21 Is the heat flux between thermocouples 1, 2, q 32 Is the heat flux between the thermocouples 2, 3.
As a further improvement of the invention, q 21 And q is 32 Is calculated byThe formula is as follows:
Figure BDA0003838174660000032
Figure BDA0003838174660000033
wherein f (T1), f (T2) and f (T3) represent the thermal conductivity of the intact layer at the temperature of the thermocouples 1, 2 and 3.
As a further improvement of the invention, when L1< H3, based on the principle that the radial heat flow intensity of the blast furnace is equal:
q 12 ＝q 2T0 ＝q 3T0
wherein q is 2T0 Is the heat flux between thermocouple 2, T0, q 3T0 Is the heat flux between thermocouple 3, T0, q 2T0 And q is 3T0 The calculation formula of (a) is as follows:
Figure BDA0003838174660000041
Figure BDA0003838174660000042
wherein f (T0) represents the thermal conductivity of the intact layer at a temperature of T0, λ 2 Representing the thermal conductivity of the embrittlement layer;
the calculation formula for obtaining the boundary temperature T0 of the intact layer and the brittle layer and the thickness L1 of the intact layer is as follows:
Figure BDA0003838174660000043
Figure BDA0003838174660000044
wherein λ is c Is a temperatureAnd tc is the heat conductivity coefficient of the carbon brick in factory detection, and b is the temperature coefficient.
As a further improvement of the invention, when L1 is more than H3, the remaining state of the carbon brick is good, and the calculation formula of L1= H3, the boundary temperature T0 of the intact layer and the brittle layer and the thickness L1 of the intact layer is as follows:
T0＝T3
L1＝H3。
as a further improvement of the present invention, in step S4, the calculation method of the embrittlement layer thickness L2 and the iron-impregnated layer thickness L3 is as follows:
based on the principle that the radial heat flow intensity of the blast furnace is equal:
q 12 ＝q 34 ＝q 45
wherein q is 34 Heat flux between thermocouple 3 and 907 ℃, q 45 Is a heat flux between 907 ℃ and 1150 ℃, q 45 The calculation formula of (c) is as follows:
Figure BDA0003838174660000045
wherein λ is 3 Represents the thermal conductivity of the iron-infiltrated layer;
the calculation formula of the iron-infiltrated layer L3 is as follows:
Figure BDA0003838174660000051
when L1 is present<At H3, q 34 The calculation formula of (a) is as follows:
Figure BDA0003838174660000052
the calculation formula of the embrittlement layer L2 is as follows:
Figure BDA0003838174660000053
when L1> H3, q 34 The calculation formula of (a) is as follows:
Figure BDA0003838174660000054
the calculation formula of the embrittlement layer L2 is as follows:
Figure BDA0003838174660000055
wherein b is a temperature coefficient.
As a further improvement of the invention, the steps S1 to S4 are repeated, the lengths and the height information of the boundary lines of the intact carbon brick layer, the embrittlement layer and the iron infiltration layer on different heights h of the furnace hearth are calculated, the lengths and the height information of the boundary lines of the intact carbon brick layer, the embrittlement layer, the iron infiltration layer and the molten iron are marked as (L1, h), (L1 + L2, h) and (L1 + L2+ L3, h) in sequence, and the discrete boundary points of the erosion layers on different heights of the carbon brick are subjected to continuity by adopting a Bessel interpolation algorithm to obtain a visual graph of the erosion degree of the carbon brick on the furnace hearth.
The invention has the beneficial effects that:
1. according to the invention, by utilizing the thermocouple position and temperature data in the furnace opening period and the characteristics that the carbon brick is not corroded in the furnace opening period and the actual length of the intact layer is known, the calculation accuracy of the formula can be conveniently verified, and the linear relation between the thermal conductivity coefficient of the carbon brick and the temperature of the intact layer is obtained by solving, so that the temperature of the boundary between the intact layer and the brittle layer is calculated and obtained by utilizing the formula in the middle and later periods and combining the principle of equal heat flux, and the accurate thickness of the intact layer of the carbon brick is obtained by calculation based on the temperature of the boundary.
2. According to the invention, the carbon brick is divided into an intact layer, an embrittled layer and an iron-infiltrated layer along the radial direction of the hearth according to the erosion change of the carbon brick, the physical characteristic that the thermal conductivity of the intact layer of the carbon brick changes along with the temperature and the characteristic that the carbon brick is eroded to be integrally transformed into the intact layer, the embrittled layer and the iron-infiltrated layer are fully considered on the basis of the temperature distribution characteristic of each layer, the boundary temperature of the intact layer and the embrittled layer and the thermal conductivity of the embrittled layer and the iron-infiltrated layer are calculated by utilizing the linear relation of the thermal conductivity of the carbon brick of the intact layer and the temperature, and the thermal conductivity of the embrittled layer and the iron-infiltrated layer are calculated, the calculation result of the residual thickness of the carbon brick is calculated and the visual establishment of the erosion degree is carried out, so that the calculated residual thickness of the carbon brick is more accurate, and the visual display of the erosion degree of the carbon brick can more visually reflect the erosion condition of the carbon brick.
3. The method is simple, data is easy to obtain, operability is strong, the thickness of the carbon bricks is calculated in different regions based on the relation of the thermal conductivity of the intact layer of the residual carbon bricks along with the temperature change, the structural change of the carbon bricks after actual erosion and the characteristics of the corresponding thermal conductivity change, the obtained calculation result can more accurately reflect the degree of erosion of the carbon bricks, so that measures beneficial to safety of the hearth can be guided, the risk of burning through of the hearth can be reduced, a scientific theoretical basis is provided for prolonging the service life of the blast furnace, and the method has wide application prospect.
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FIG. 1 is a design idea diagram of a method for visually establishing the degree of erosion of hearth carbon bricks according to the present invention.
Fig. 2 is a schematic view showing the arrangement position of the thermocouple according to the present invention.
FIG. 3 is a visual diagram of the degree of erosion of the hearth carbon bricks of the present invention.
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.
The invention provides a method for establishing a furnace hearth carbon brick erosion degree visualization, which comprises the following steps:
s1, collecting arrangement positions and temperature data of a hearth thermocouple of a blast furnace in a furnace opening period and a non-furnace opening period, recording the temperature of the thermocouple in the furnace opening period as Tf, recording the insertion depth of the thermocouple close to the center of the blast furnace as H3, and preprocessing the temperature data of the thermocouple in the furnace opening period and the non-furnace opening period;
s2, obtaining a thermal conductivity-temperature linear relation formula of the good carbon brick layer based on the principle that the radial heat fluxes of the blast furnace hearth are equal and combined with the thermal power even data in the furnace opening period;
s3, dividing the furnace hearth residual carbon brick into a complete layer, an embrittlement layer and an iron infiltration layer along the radial direction of the furnace hearth, recording the thicknesses of the regional layers as L1, L2 and L3 respectively, obtaining the heat conductivity coefficients lambda 2 and lambda 3 of the embrittlement layer and the iron infiltration layer, judging the size relation between the complete layer thickness L1 and the thermocouple insertion depth H3 close to the center of the blast furnace through coupling calculation, and calculating the boundary temperature T0 of the complete layer and the embrittlement layer and the complete layer thickness L1 under different conditions respectively according to the judgment result and by using the heat conductivity-temperature linear relation in the step S2;
and S4, calculating the thickness L2 of the embrittlement layer and the thickness L3 of the iron-infiltrated layer by taking 1150 ℃ as a hot surface temperature critical point of the hearth and 907 ℃ as a boundary temperature point of the embrittlement layer and the iron-infiltrated layer and combining the real-time thermocouple temperature.
And S5, repeating the steps S1-S4, calculating the lengths L1, L2 and L3 of the intact layer, the embrittlement layer and the iron infiltration layer of the carbon brick at different heights h of the hearth, and adopting an interpolation algorithm to continuously disperse points to obtain a visual diagram of the erosion degree of the carbon brick of the hearth.
Specifically, in step S1, at least three thermocouples 1, 2, and 3 with different insertion depths are respectively arranged in the hearth, the calculation starting point of the insertion depth is calculated from the starting point of the carbon brick in the direction close to the furnace shell, the insertion depths are H1, H2, and H3, H1< H2< H3, and the temperature data of the thermocouples 1, 2, and 3 during the blow-in period are Tf1, tf2, and Tf3, respectively; the temperature data of the thermocouples 1, 2 and 3 in the non-blow-in period are respectively T1, T2 and T3; the thermocouple temperature data preprocessing comprises the step of eliminating data with the temperature not conforming to T3> T2> T1 and Tf3> Tf2> Tf 1.
Specifically, in step S2, the step of solving the linear relation between the thermal conductivity and the temperature of the intact carbon brick layer is as follows:
the linear relation between the thermal conductivity coefficient and the temperature of the intact layer of the carbon brick is as follows:
λ＝f(t)＝λ c +b(t-t c )
based on the fact that the heat fluxes among the thermocouples 1 and 2 and between the thermocouples 2 and 3 are equal in the furnace opening period, the temperature coefficient b can be calculated by substituting the heat conductivity coefficient-temperature linear relation of the complete carbon brick layer, and the calculation method is as follows:
Figure BDA0003838174660000081
the temperature coefficient b is simplified as follows:
b＝2λ c [(H2-H1)(Tf3-Tf2)-(H3-H2)(Tf2-Tf1)]×[(H3-H2)(Tf2-Tf1)(Tf2+Tf1-2tc)-(H2-H1)(Tf3-Tf2)(Tf3+Tf2-2tc)] -1
the linear relation of the thermal conductivity coefficient and the temperature of the carbon brick intact layer is obtained as follows:
λ＝f(t)＝λ c +2λ c [(H2-H1)(Tf3-Tf2)-(H3-H2)(Tf2-Tf1)]×[(H3-H2)(Tf2-Tf1)(Tf2+Tf1-2tc)-(H2-H1)(Tf3-Tf2)(Tf3+Tf2-2tc)] -1 (t-tc)
wherein λ is c The coefficient of heat conductivity of the carbon brick factory test at the temperature tc, and the coefficient of temperature b.
Specifically, in step S3, the coupling calculation is to calculate a heat flux difference value c between the thermocouples 1 and 2 and the thermocouples 2 and 3, determine the relationship between the intact layer thickness L1 and H3 according to the heat flux difference value c and a preset difference value a, and if c is greater than the preset difference value a, consider L1 to be less than H3; if c is smaller than the preset difference value a, considering that L1 is larger than H3; the calculation formula of the heat flux difference value c is as follows:
Figure BDA0003838174660000082
wherein q is 21 Is the heat flux between thermocouples 1, 2, q 32 Is the heat flux between thermocouples 2, 3.
Specifically, q is 21 And q is 32 The calculation formula of (a) is as follows:
Figure BDA0003838174660000083
Figure BDA0003838174660000084
the heat flux difference value c is obtained by simplification as follows:
Figure BDA0003838174660000085
wherein f (T1), f (T2), f (T3) represent the thermal conductivity of the intact layer at the temperatures of thermocouples 1, 2, 3.
Specifically, when L1< H3, based on the principle that the radial heat flow intensity of the blast furnace is equal:
q 12 ＝q 2T0 ＝q 3T0
wherein q is 2T0 Is the heat flux between thermocouple 2, T0, q 3T0 Is the heat flux between thermocouple 3, T0, q 2T0 And q is 3T0 The calculation formula of (a) is as follows:
Figure BDA0003838174660000091
Figure BDA0003838174660000092
wherein f (T0) represents the thermal conductivity of the intact layer at a temperature of T0, λ 2 Representing the thermal conductivity of the embrittlement layer;
the calculation formula for obtaining the boundary temperature T0 of the intact layer and the brittle layer and the thickness L1 of the intact layer is as follows:
Figure BDA0003838174660000093
Figure BDA0003838174660000094
wherein λ is c The coefficient of heat conductivity of the carbon brick factory test at the temperature tc, and the coefficient of temperature b.
Specifically, when L1> H3, indicating that the remaining state of the carbon brick is good, the calculation formula of L1= H3, the boundary temperature T0 between the intact layer and the brittle layer, and the thickness L1 of the intact layer is as follows:
T0＝T3
L1＝H3。
specifically, in step S4, the temperature interval between the iron-infiltrated layer and the protective layer is 907 to 1150 ℃, and the calculation method of the embrittlement layer thickness L2 and the iron-infiltrated layer thickness L3 is as follows:
based on the principle that the radial heat flow intensity of the blast furnace is equal:
q 12 ＝q 34 ＝q 45
wherein q is 34 Heat flux between thermocouple 3 and 907 ℃, q 45 Is a heat flux between 907 ℃ and 1150 ℃, q 45 The calculation formula of (a) is as follows:
Figure BDA0003838174660000095
wherein λ is 3 Represents the thermal conductivity of the iron-infiltrated layer;
the calculation formula of the iron-infiltrated layer L3 is as follows:
Figure BDA0003838174660000101
when L1 is present<H3 is, q 34 The calculation formula of (a) is as follows:
Figure BDA0003838174660000102
the calculation formula of the embrittlement layer L2 is as follows:
Figure BDA0003838174660000103
when L1> H3, q 34 The calculation formula of (a) is as follows:
Figure BDA0003838174660000104
the calculation formula of the embrittlement layer L2 is as follows:
Figure BDA0003838174660000105
wherein b is a temperature coefficient.
Specifically, the steps S1 to S4 are repeated, the lengths L1, L2 and L3 of the intact carbon brick layer, the embrittlement layer and the iron infiltration layer at different heights h of the hearth are calculated, and the lengths and the height information of the boundary lines of the intact carbon brick layer, the embrittlement layer, the iron infiltration layer and the molten iron are marked as (L1, h), (L1 + L2, h) and (L1 + L2+ L3, h) in sequence. And (3) adopting a Bessel interpolation algorithm to carry out serialization on discrete boundary points of each erosion layer on different heights of the carbon brick to obtain a furnace hearth carbon brick erosion degree visual map.
The following describes a method for establishing a furnace hearth carbon brick erosion degree visualization provided by the present invention with reference to specific embodiments.
Example 1
The embodiment provides a method for establishing a furnace hearth carbon brick erosion degree visualization, which specifically comprises the following steps:
s1, collecting arrangement positions and temperature data of the furnace hearth thermocouples in the blow-in period and the later production period of the blast furnace, wherein the insertion depths H1, H2 and H3 of the thermocouples 1, 2 and 3 are 0.20m,0.33m and 0.73m respectively. The temperatures of thermocouples 1, 2 and 3 during the blow-in period of the blast furnace are respectively recorded as Tf 1 、Tf 2 、Tf 3 The temperatures of thermocouples 1, 2 and 3 at the later stage of production are respectively marked as T 1 、T 2 、T 3 Since thermocouple 3 is closest to the center of the hearth, the temperature will not meet Tf 3 >Tf 2 >Tf 1 And T 3 >T 2 >T 1 The data are removed to obtain temperature data of the temperature measurement area, and the temperature data are shown in a table 1;
TABLE 1 temperature data of thermocouples at various periods of the blast furnace
In the blow-in period Temperature of Non-blow-in period Temperature of
Tf 1 77.4 T 1 131.2
Tf 2 126.8 T 2 223.6
Tf 3 275.9 T 3 515.7
S2, establishing a linear mathematical model of the thermal conductivity coefficient lambda and the temperature t of the carbon brick intact layer as follows:
λ＝f(t)＝λ c +b(t-t c ) (1)
wherein λ is c Is a temperature t c B is a temperature coefficient;
the heat conductivity coefficient of the carbon brick at 600 ℃ of 20.5W/m ℃ is substituted into the formula (1) to obtain:
λ＝f(t)＝20.5+b(t-600) (2)
further, solving based on the principle that the radial heat flux of the blast furnace hearth is equal:
Figure BDA0003838174660000111
inserting the insertion depths H1, H2 and H3 of the thermocouples 1, 2 and 3 in the furnace opening period, the temperatures Tf1, tf2 and Tf3 and the formula (2) into the formula (3) to obtain a temperature coefficient b:
Figure BDA0003838174660000112
and further substituting the temperature parameter b to obtain a relational expression between the heat conductivity coefficient of the carbon brick and the temperature:
λ＝f(t)＝0.0037t+18.3038 (5)
s3, dividing the residual carbon brick of the hearth into a complete layer, an embrittled layer and an iron-infiltrated layer according to the structure along the radial direction of the hearth, wherein the thermal conductivity coefficient lambda of the complete layer is 1 The length of the intact layer is recorded as L1 when the temperature changes; coefficient of heat conductivity lambda of embrittled layer carbon brick 2 The temperature is 6.5W/m ℃, and the length is recorded as L2; heat conductivity coefficient lambda of iron-impregnated carbon brick 3 The temperature is 8.7W/m ℃, and the length is recorded as L3; calculating the thermocouples 1, 2 and the heatComparing the heat flux difference value c between the galvanic couples 2 and 3 with the preset difference value of 0.05 to determine the relationship between the intact layer thickness L1 and H3, in this example, the calculation result of the heat flux difference value c is as follows:
Figure BDA0003838174660000121
thus, L1< H3.
Figure BDA0003838174660000122
Figure BDA0003838174660000123
The relationship can be solved in parallel:
T0＝489.84℃
L1＝0.718m
s4, taking 1150 ℃ as a temperature critical point of a hot surface of the hearth, depositing harmful element zinc at one end, close to the iron-infiltrated layer, of the embrittlement layer, taking the boiling point 907 ℃ of zinc as a boundary point of the embrittlement layer and the iron-infiltrated layer so as to calculate the thicknesses of the embrittlement layer and the iron-infiltrated layer more accurately, calculating the thickness L2 of the embrittlement layer and the thickness L3 of the iron-infiltrated layer by combining the temperature of a real-time thermocouple, and calculating the following calculation results:
Figure BDA0003838174660000124
Figure BDA0003838174660000125
and S5, repeating the steps S1 to S4, calculating the lengths L1, L2 and L3 of the intact carbon brick layer, the embrittlement layer and the iron infiltration layer at different heights h of the hearth, marking the lengths and the height information of the boundary lines of the intact carbon brick layer, the embrittlement layer, the iron infiltration layer and the molten iron, and sequentially marking as (L1, h), (L1 + L2, h) and (L1 + L2+ L3, h). And (3) adopting a Bessel interpolation algorithm to carry out serialization on discrete boundary points of each erosion layer on different heights of the carbon brick to obtain a furnace hearth carbon brick erosion degree visual image.
The specific calculation process is shown in the following table 2:
Figure BDA0003838174660000131
further, a visual diagram of the degree of erosion of the hearth can be drawn according to table 2, and as shown in fig. 3, the degree of erosion of the carbon bricks can be intuitively understood from fig. 3.
In conclusion, the invention discloses a method for establishing furnace hearth carbon brick erosion degree visualization, which is characterized in that the calculation accuracy of a formula can be conveniently verified by utilizing the thermocouple position and temperature data in the furnace opening period and the characteristics that the carbon brick is not eroded in the furnace opening period and the actual length of a perfect layer is known, and the linear relation between the heat conductivity coefficient of the carbon brick and the temperature of the perfect layer is obtained by solving, so that the temperature of the boundary between the perfect layer and an embrittled layer is calculated and obtained by utilizing the formula in the middle and later periods and combining the principle of equal heat flux, and the accurate thickness of the perfect layer of the carbon brick is calculated and obtained based on the temperature of the boundary; and then dividing the carbon brick into a complete layer, an embrittled layer and an iron-infiltrated layer along the radial direction of the hearth according to the erosion change of the carbon brick, fully considering the characteristic that the structure of the carbon brick after being eroded is changed into the complete layer, the embrittled layer and the iron-infiltrated layer from the whole state based on the temperature distribution characteristics of each layer of area, and calculating the residual thickness of the carbon brick and visually establishing the erosion degree by utilizing the boundary temperature and the heat conductivity coefficients of the embrittled layer and the iron-infiltrated layer, so that the condition that the residual thickness of the carbon brick is calculated and is more accurate due to the fact that the relation of the actual heat conductivity coefficient of the complete layer of the carbon brick along with the temperature change and the change of the heat conductivity coefficient of the carbon brick after being eroded are not fully considered and the deviation of the calculation result and the actual result of the residual thickness of the carbon brick is larger is avoided, and the erosion condition of the carbon brick can be more visually displayed simultaneously. The method is simple, data is easy to obtain, operability is strong, the thickness of the carbon bricks is calculated in different regions based on the relation of the thermal conductivity of the intact layer of the residual carbon bricks along with the temperature change, the structural change of the carbon bricks after actual erosion and the characteristics of the corresponding thermal conductivity change, the obtained calculation result can more accurately reflect the degree of erosion of the carbon bricks, so that measures beneficial to safety of the hearth can be guided, the risk of burning through of the hearth can be reduced, a scientific theoretical basis is provided for prolonging the service life of the blast furnace, and the method has wide application prospect.
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 establishing furnace hearth carbon brick erosion degree visualization is characterized by comprising the following steps:
s1, collecting hearth thermocouple arrangement positions and temperature data of a blast furnace in a furnace opening period and a non-furnace opening period, recording the thermocouple temperature in the furnace opening period as Tf, recording the insertion depth of the thermocouple close to the center of the blast furnace as H3, and preprocessing the temperature data of the thermocouple in the furnace opening period and the non-furnace opening period;
s2, obtaining a thermal conductivity-temperature linear relation formula of the good carbon brick layer based on the principle that the radial heat fluxes of the blast furnace hearth are equal and combined with the thermal power even data in the furnace opening period;
s3, dividing the furnace hearth residual carbon brick into a complete layer, an embrittlement layer and an iron-infiltrated layer along the radial direction of the furnace hearth, recording the thicknesses of the layers in all regions as L1, L2 and L3 respectively, obtaining heat conductivity coefficients lambda 2 and lambda 3 of the embrittlement layer and the iron-infiltrated layer, judging the size relation between the complete layer thickness L1 and the thermocouple insertion depth H3 close to the center of the blast furnace through coupling calculation, and calculating the boundary temperature T0 of the complete layer and the embrittlement layer and the complete layer thickness L1 under different conditions according to the judgment result and by using the heat conductivity-temperature linear relation in the step S2;
s4, calculating the thickness L2 of the embrittlement layer and the thickness L3 of the iron-cementation layer by taking 1150 ℃ as a hot surface temperature critical point of a hearth and 907 ℃ as a boundary temperature point of the embrittlement layer and the iron-cementation layer and combining with the temperature of a real-time thermocouple;
and S5, repeating the steps S1-S4, calculating the lengths L1, L2 and L3 of the intact layer, the embrittlement layer and the iron infiltration layer of the carbon brick at different heights h of the hearth, and adopting an interpolation algorithm to continuously disperse points to obtain a visual diagram of the erosion degree of the carbon brick of the hearth.
2. The method for establishing the visual degree of the erosion of the hearth carbon bricks according to claim 1, wherein the visual degree of the erosion of the hearth carbon bricks is set as follows: in the step S1, at least three thermocouples 1, 2, and 3 with different insertion depths are respectively arranged in the hearth, the calculation starting point of the insertion depth starts to be calculated from the starting point of the carbon brick in the direction close to the furnace shell, the insertion depths are H1, H2, and H3, H1< H2< H3, and the temperature data of the thermocouples 1, 2, and 3 during the blow-in period are Tf1, tf2, and Tf3, respectively; the temperature data of the thermocouples 1, 2 and 3 in the non-blow-in period are respectively T1, T2 and T3; the thermocouple temperature data preprocessing comprises the step of eliminating data with the temperature not conforming to T3> T2> T1 and Tf3> Tf2> Tf 1.
3. The method for establishing the visual degree of the erosion of the hearth carbon bricks according to claim 2, is characterized in that: in step S2, the thermal conductivity-temperature linear relation of the intact carbon brick layer is:
λ＝f(t)＝λ c +b(t-t c )
b＝2λ c [(H2-H1)(Tf3-Tf2)-(H3-H2)(Tf2-Tf1)]×[(H3-H2)(Tf2-Tf1)(Tf2+Tf1-2tc)-(H2-H1)(Tf3-Tf2)(Tf3+Tf2-2tc)] -1
wherein λ is c Is a temperature t c The heat conductivity coefficient of the lower carbon brick in factory detection, b is the temperature coefficient.
4. The method for establishing the visual degree of the erosion of the hearth carbon bricks according to claim 2, is characterized in that: in step S3, the coupling calculation is to calculate a heat flux difference value c between the thermocouples 1 and 2 and the thermocouples 2 and 3, so as to determine a relationship between the thicknesses L1 and H3 of the intact layers.
5. The method for establishing the visual degree of the erosion of the hearth carbon bricks according to claim 4, is characterized in that: if c is larger than the preset difference value a, considering that L1 is less than H3; if c is smaller than the preset difference value a, considering that L1 is larger than H3; the calculation formula of the heat flux difference value c is as follows:
Figure FDA0003838174650000021
wherein q is 21 Is the heat flux between thermocouples 1, 2, q 32 Is the heat flux between the thermocouples 2, 3.
6. The method for establishing the visual degree of the erosion of the hearth carbon bricks according to claim 5, is characterized in that: q. q.s 21 And q is 32 The calculation formula of (a) is as follows:
Figure FDA0003838174650000022
Figure FDA0003838174650000023
wherein f (T1), f (T2) and f (T3) represent the thermal conductivity of the intact layer at the temperature of the thermocouples 1, 2 and 3.
7. The method for establishing the visual degree of the erosion of the hearth carbon bricks according to claim 6, wherein the visual degree of the erosion of the hearth carbon bricks is set as follows: when L1 is less than H3, based on the principle that the radial heat flow intensity of the blast furnace is equal, the boundary temperature T0 of the intact layer and the brittle layer and the thickness L1 of the intact layer can be obtained by the following calculation formula:
Figure FDA0003838174650000024
Figure FDA0003838174650000025
wherein λ is c The coefficient of heat conductivity of the carbon brick factory test at the temperature tc, and the coefficient of temperature b.
8. The method for establishing the visual degree of the erosion of the hearth carbon bricks according to claim 6, wherein the visual degree of the erosion of the hearth carbon bricks is set as follows: when L1 is larger than H3, the residual state of the carbon brick is good, and the calculation formula of L1= H3, the boundary temperature T0 of the intact layer and the brittle layer and the thickness L1 of the intact layer is as follows:
T0＝T3
L1＝H3。
9. the method for establishing the visual degree of the erosion of the hearth carbon bricks according to claim 1, wherein the visual degree of the erosion of the hearth carbon bricks is set as follows: in step S4, the calculation method of the embrittlement layer thickness L2 and the iron-carburized layer thickness L3 is as follows:
based on the principle that the radial heat flow intensity of the blast furnace is equal:
q 12 ＝q 34 ＝q 45
wherein q is 34 Heat flux between thermocouple 3 and 907 ℃, q 45 Is a heat flux between 907 ℃ and 1150 ℃, q 45 The calculation formula of (c) is as follows:
Figure FDA0003838174650000031
wherein λ is 3 Represents the thermal conductivity of the iron-infiltrated layer;
the calculation formula of the iron-infiltrated layer L3 is as follows:
Figure FDA0003838174650000032
when L1 is present<H3 is, q 34 The calculation formula of (a) is as follows:
Figure FDA0003838174650000033
the calculation formula of the embrittlement layer L2 is as follows:
Figure FDA0003838174650000034
when L1> H3, q 34 The calculation formula of (a) is as follows:
Figure FDA0003838174650000035
the calculation formula of the embrittlement layer L2 is as follows:
Figure FDA0003838174650000041
wherein b is a temperature coefficient.
10. The method for establishing the visual degree of the erosion of the hearth carbon bricks according to claim 1, wherein the visual degree of the erosion of the hearth carbon bricks is set as follows: and (4) repeating the steps S1-S4, calculating the lengths L1, L2 and L3 of the intact carbon brick layer, the embrittlement layer and the iron infiltration layer on different heights h of the hearth, marking the lengths and the height information of the boundary lines of the intact carbon brick layer, the embrittlement layer, the iron infiltration layer and the molten iron as (L1, h), (L1 + L2+ L3, h), and carrying out serialization on the discrete boundary points of the erosion layers on different heights of the carbon brick by adopting a Bessel interpolation algorithm to obtain a visual diagram of the erosion degree of the carbon brick of the hearth.
CN202211093983.9A 2022-09-08 2022-09-08 Method for establishing furnace hearth carbon brick erosion degree visualization Pending CN115563748A (en)

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