A method for determining the opening position of a blast furnace residual iron mouth for smelting vanadium-titanium magnetite

Abstract

The present application provides a kind of determination method of blast furnace residual iron mouth opening position.The present application is based on blast furnace bottom brick lining structure, bottom brick lining heat transfer coefficient, temperature monitoring of thermocouple buried in bottom brick lining, one-dimensional steady heat transfer equation is applied and the calculation is carried out by assuming molten iron erosion depth, and compared with working thermocouple temperature, so that the remaining thickness of brick lining is calculated in the cycle process of assumption-calculation-contrast-reassumption.The present application is suitable for blast furnace with ≥3 layers of temperature measuring thermocouples buried in bottom brick lining of hearth, 1 layer of temperature measuring thermocouples buried in lower hearth base, each layer of thermocouples in bottom brick lining of hearth is uniformly distributed in circumferential direction, and the insertion depth of thermocouples in different layers of thermocouples is consistent in radial direction.The present application can more accurately calculate the erosion of molten iron to bottom brick lining and the opening position of blast furnace residual iron mouth.

Description

Technical Field

[0001] This invention belongs to the technical field of blast furnace residual iron tapping opening position calculation for vanadium-titanium magnetite smelting, and relates to a method for determining the opening position of blast furnace residual iron tapping, particularly a method for determining the opening position of blast furnace residual iron tapping in vanadium-titanium magnetite smelting. Background Technology

[0002] For blast furnace smelting, the working environment in the hearth area is extremely harsh. It is constantly immersed in high-temperature slag and iron, and under the heavy pressure of thousands of tons of ore and coke. The service life of the hearth directly determines the overall lifespan of the blast furnace. During normal blast furnace production, the hearth and bottom lining are subjected to long-term erosion from molten iron penetration, corrosion from metals such as potassium, sodium, lead, and zinc, scouring from molten iron circulation, and thermal stress damage. In the pursuit of blast furnace production efficiency and reducing energy consumption per ton of iron produced, high smelting intensity often accelerates the erosion and damage to the hearth and bottom lining. Molten iron gradually seeps into the bottom lining, causing the blast furnace bottom temperature to rise. Once the erosion exceeds the safety threshold, the hearth risks burning through. Therefore, when the bottom lining of the hearth is eroded to a certain extent, the blast furnace can no longer continue safe production, and the blast furnace's service life ends. Regardless of whether the hearth reaches its designed lifespan under normal use or is prematurely terminated due to accelerated hearth erosion, a suitable location for the residual iron taphole opening must be found before a major overhaul. This is because the centerline of the blast furnace taphole is higher than the dead iron layer in the hearth. Hundreds or even thousands of tons of high-temperature molten iron accumulated below the centerline of the taphole must be drained from the hearth to facilitate the safe removal of the hearth and furnace bottom lining after shutdown. If the residual iron taphole is poorly positioned, it will lead to difficulties in tapping the residual iron, resulting in a significant amount of residual iron remaining in the hearth. This not only reduces the safety of the hearth and furnace bottom removal process but also increases the workload. This is especially true for blast furnaces smelting vanadium-titanium magnetite. Due to the formation and protective effect of high-melting-point titanium carbonitride, deposits containing a high amount of titanium carbonitride have high hardness, significantly increasing the difficulty of subsequent construction and the required manpower and costs.

[0003] Currently, the main methods for determining the location of the residual iron tapping point before blast furnace shutdown and major overhaul are measurement and empirical formula calculation. The measurement method primarily involves measuring the furnace shell temperature. Thermocouples are inserted at different elevations in the hearth and furnace bottom to measure the highest temperature elevation of the furnace shell, thus determining the elevation of the residual iron tapping point. This, combined with the convenience of arranging the residual iron trench and the residual iron tapping platform, determines the opening orientation of the tapping point. This method is particularly suitable for ordinary mining and metallurgical blast furnaces that are easily affected by molten iron circulation erosion, and whose furnace bottoms are prone to "garlic head" or "elephant foot" erosion. The area with the highest furnace shell temperature is often the area with the deepest molten iron erosion.

[0004] However, for blast furnaces smelting vanadium-titanium magnetite, the erosion of the furnace bottom by molten iron often presents a "bowl-bottom" pattern. Due to the varying thickness of the remaining brick lining in the circumferential direction, the area with the highest furnace shell temperature is not necessarily the lowest point where residual iron remains. Therefore, during major overhauls of blast furnaces smelting vanadium-titanium magnetite, the elevation of the residual iron taphole is often determined by empirical formulas. The main formulas referenced are: X = k × d × lg(t0 / t) proposed by the former Ministry of Metallurgical Industry's Furnace Body Survey Group; L = (1 / N) × (1350-t) proposed by Anshan Iron and Steel Plant; and Moisenk's formula X = d / k × 1 / u × lg(t1 / t). Since these empirical formulas are often derived from blast furnaces smelting ordinary ores, significant discrepancies frequently arise between the calculated results and the final actual results during application.

[0005] Therefore, finding a more accurate method for determining the location of residual iron in blast furnaces and solving the technical problems existing in the current methods is very important for blast furnace smelting of vanadium-titanium magnetite, and it is also one of the problems that many front-line researchers and blast furnace smelting enterprises in this field urgently need to solve. Summary of the Invention

[0006] In view of this, the technical problem to be solved by the present invention is to provide a method for determining the opening position of the blast furnace residual iron taphole, particularly a method for determining the opening position of the blast furnace residual iron taphole in vanadium-titanium magnetite smelting. The calculation method provided by the present invention can more accurately calculate the erosion of the furnace bottom brick lining by molten iron and the opening position of the blast furnace residual iron taphole, improving the accuracy of the residual iron taphole opening, and can be widely applied in the field of blast furnace ironmaking.

[0007] This invention provides a method for determining the opening position of the residual iron taphole in a blast furnace, comprising the following steps:

[0008] 1) Taking the center of the blast furnace hearth as a reference, select two temperature measurement points of different brick layers in the same circumferential angle direction and the same radius, and denot them as upper temperature measurement point Bk and lower temperature measurement point Bn. Set the temperature of the molten iron erosion line. Taking the upper temperature measurement point Bk as a reference, start from the first or zth brick of the furnace bottom and assume that the upper surface of the first or zth brick is the location of the molten iron erosion line. Then the temperature of the upper surface of the first or zth brick of the furnace bottom is the temperature of the molten iron erosion line.

[0009] When the surface temperature of the first layer of bricks at the bottom of the furnace is the erosion line temperature of molten iron, the heat transfer in the vertical direction of the bottom of the furnace is regarded as a one-dimensional steady-state heat transfer. Based on the heat flow from the first layer of bricks downwards, the heat flow intensity and the surface temperature of any layer of bricks above the upper temperature measurement point Bk are obtained through calculation.

[0010] 2) Based on the heat flux intensity obtained in the above steps, the surface temperature t of each brick layer below the brick layer where the upper temperature measuring point Bk is located is calculated again.m ;

[0011] 3) When the brick layer m is the same as the brick layer with temperature point Bn below it, the surface temperature t of the brick layer is set. m The measured temperature t at the lower temperature measurement point Bn n A comparison is made, and a judgment is made based on the comparison results. When |t m -t n If the temperature is below a certain level, the assumption of the location of the molten iron erosion line is considered accurate, and this location is taken as the opening position of the blast furnace residual iron taphole.

[0012] Preferably, the blast furnace includes a blast furnace for smelting vanadium-titanium magnetite;

[0013] The set temperature for the molten iron erosion line is specifically 1150℃;

[0014] The brick layer where z is greater than 1 and less than Bk.

[0015] Preferably, the heat flow is transferred sequentially from the first layer of bricks to the upper layer temperature measuring points from top to bottom, and the calculation formula for the heat flow intensity in step 1) is shown in formula (I):

[0016]

[0017] Where, λ ave t0 is the average thermal conductivity of the brick layer from the first layer to the upper temperature measuring point Bk; X is the total thickness of the brick layer from the first layer to the upper temperature measuring point Bk, in meters; t0 is the temperature of the molten iron erosion line, in degrees Celsius; t0 is the temperature of the molten iron erosion line. k q represents the temperature at the upper temperature measurement point Bk, in °C; q represents the heat flux intensity.

[0018] Preferably, the surface temperature of any brick layer above the upper temperature measuring point Bk is calculated using the formula shown in formula (II):

[0019]

[0020] Specifically, there is i layers of bricks between the first layer of bricks and the layer containing the upper temperature measuring point Bk, with each layer having a thickness of X. i The thermal conductivity of each layer of bricks is λ. i The surface temperature of each layer of bricks is t i q represents the heat flux intensity.

[0021] Preferably, the heat flux intensity q in the formula (I) is the average heat transfer intensity transferred from the surface of the first layer of bricks to the upper layer temperature measuring point Bk;

[0022] The heat flux intensity q in the formula (II) is the precise heat transfer heat flux intensity transferred from the surface of the first layer of bricks to the surface of the next layer of bricks;

[0023] The precise heat transfer flux intensity is used to calibrate the average heat transfer flux intensity.

[0024] Preferably, the calculation formula for the recalculation is as shown in formula (III):

[0025]

[0026] Where, λ m X represents the thermal conductivity of each brick layer from the (k+1)th layer to the mth layer; m t represents the thickness of each brick layer from the (k+1)th layer to the mth layer, in meters. m t represents the surface temperature of each brick layer from the (k+1)th layer to the mth layer; k The temperature of the upper temperature measuring point Bk.

[0027] Preferably, the specified temperature is 20°C;

[0028] The comparison process includes the following steps:

[0029] When t m -t n If the temperature is higher than a certain value, it indicates that the assumed location of the molten iron erosion line is far from the location of the upper temperature measuring point Bk in the brick layer, and the heat flow intensity is small. Therefore, it is assumed that the temperature of the molten iron erosion line is the upper surface temperature below the second layer of bricks, and the temperature t is recalculated according to steps (1) and (2). m Perform calculations, and then make a judgment.

[0030] Preferably, the comparison process further includes the following steps:

[0031] When t n -t m If the temperature exceeds a certain threshold, it indicates that the assumed location of the molten iron erosion line is close to the location of the upper temperature measuring point Bk within the brick layer, indicating a high heat flow intensity. Therefore, the bisection method is used to re-assume the location of the molten iron erosion line and move it upwards by half a brick's distance. The temperature t is then re-evaluated. m Perform calculations, and then make a judgment.

[0032] Preferably, the opening position of the blast furnace residual iron tap includes the lowest position of the residual iron tap opening;

[0033] The determination method further includes the following verification steps:

[0034] Following steps 1) to 3), select one or more other directions, calculate the temperature measurement points of two different brick layers on the same circumferential angle direction and the same radius, obtain one or more iron erosion line positions, and then compare or verify them as the lowest position of the residual iron taphole opening.

[0035] Preferably, the determining method further includes the step of determining the opening direction of the residual iron tap;

[0036] The specific method for determining the opening direction of the residual iron outlet involves selecting the opening direction of the residual iron outlet based on the construction of the residual iron trench and the residual iron platform.

[0037] This invention provides a method for determining the location of the blast furnace taphole opening, comprising the following steps: First, taking the center of the blast furnace hearth as a reference, two temperature measuring points of different brick layers are selected on the same circumferential angle direction and the same radius, denoted as the upper layer temperature measuring point Bk and the lower layer temperature measuring point Bn. The molten iron erosion line temperature is set. Using the upper layer temperature measuring point Bk as a reference, starting from the first or zth layer of bricks at the bottom of the furnace, it is assumed that the upper surface of the first or zth layer of bricks is the location of the molten iron erosion line. Then, the first or zth layer of bricks at the bottom of the furnace... The surface temperature of the upper surface of the z-layer bricks is the erosion line temperature of the molten iron. When the surface temperature of the upper surface of the first layer of bricks at the furnace bottom is the erosion line temperature of the molten iron, the heat transfer in the vertical direction of the furnace bottom is considered as one-dimensional steady-state heat transfer. Based on the heat flow from the first layer of bricks downwards, the heat flow intensity and the surface temperature of any layer of bricks above the upper temperature measuring point Bk are calculated. Then, based on the heat flow intensity obtained in the above steps, the surface temperatures t of each layer of bricks below the upper temperature measuring point Bk are calculated again. m Finally, when the brick layer m has the same temperature as the brick layer with temperature point Bn below it, the surface temperature t of the brick layer is set. m The measured temperature t at the lower temperature measurement point Bn n A comparison is made, and a judgment is made based on the comparison results. When |t m -t n Below a certain temperature, the assumed location of the molten iron erosion line is considered accurate, and this location is taken as the opening position of the blast furnace residual iron taphole. Compared with existing technologies, this invention specifically designs a method for determining the opening position of the blast furnace residual iron taphole, a method for determining the opening position of the blast furnace residual iron taphole in vanadium-titanium magnetite smelting. This invention can help ironmaking production personnel determine the erosion area of ​​the blast furnace bottom, accurately predict the depth of molten iron in the hearth and the opening position of the residual iron taphole at the end of the furnace service, improve the accuracy of the residual iron taphole opening, reduce the safety risks caused by trial and error in the residual iron taphole opening, reduce the workload of hearth dismantling during major overhauls, and can be widely applied in the field of blast furnace ironmaking.

[0038] The method for determining the opening position of the blast furnace residual iron taphole provided by this invention is based on the blast furnace bottom brick lining structure, the heat transfer coefficient of the bottom brick lining, and the temperature monitored by thermocouples embedded in the bottom brick lining, and applies a one-dimensional steady-state heat transfer equation. The method involves assuming the depth of molten iron erosion and calculating it, then comparing it with the operating thermocouple temperature. Through a cycle of assumption, calculation, comparison, and re-assumption, the remaining thickness of the brick lining is calculated. This invention is applicable to blast furnaces where ≥3 layers of thermocouples are embedded in the bottom brick lining of the hearth, and 1 layer of thermocouples is embedded in the furnace foundation below the hearth. In these furnaces, the thermocouples in each layer of the bottom brick lining are distributed at a consistent angle in the circumferential direction, and the insertion depth of different layers of thermocouples is consistent in the radial direction. The bottom brick lining is composed of composite mullite bricks, dense clay bricks, semi-graphite carbon bricks, or carbon bricks. The calculation method provided by this invention can more accurately calculate the erosion of the bottom brick lining by molten iron and the location of the blast furnace residual iron taphole opening. Detailed Implementation

[0039] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention and not for limiting the claims of the present invention.

[0040] All terms and abbreviations used in this invention are conventional terms and abbreviations in the field. Each term and abbreviation is clear and distinct in its relevant application area, and those skilled in the art can understand it clearly, accurately, and uniquely based on the terms and abbreviations.

[0041] This invention provides a method for determining the opening position of the residual iron taphole in a blast furnace, comprising the following steps:

[0042] 1) Taking the center of the blast furnace hearth as a reference, select two temperature measurement points of different brick layers in the same circumferential angle direction and the same radius, and denot them as upper temperature measurement point Bk and lower temperature measurement point Bn. Set the temperature of the molten iron erosion line. Taking the upper temperature measurement point Bk as a reference, start from the first or zth brick of the furnace bottom and assume that the upper surface of the first or zth brick is the location of the molten iron erosion line. Then the temperature of the upper surface of the first or zth brick of the furnace bottom is the temperature of the molten iron erosion line.

[0043] When the surface temperature of the first layer of bricks at the bottom of the furnace is the erosion line temperature of molten iron, the heat transfer in the vertical direction of the bottom of the furnace is regarded as a one-dimensional steady-state heat transfer. Based on the heat flow from the first layer of bricks downwards, the heat flow intensity and the surface temperature of any layer of bricks above the upper temperature measurement point Bk are obtained through calculation.

[0044] 2) Based on the heat flux intensity obtained in the above steps, the surface temperature t of each brick layer below the brick layer where the upper temperature measuring point Bk is located is calculated again. m ;

[0045] 3) When the brick layer m is the same as the brick layer with temperature point Bn below it, the surface temperature t of the brick layer is set. m The measured temperature t at the lower temperature measurement point Bnn A comparison is made, and a judgment is made based on the comparison results. When |t m -t n If the temperature is below a certain level, the assumption of the location of the molten iron erosion line is considered accurate, and this location is taken as the opening position of the blast furnace residual iron taphole.

[0046] This invention first takes the center of the blast furnace hearth as a reference, and selects two temperature measuring points of different brick layers on the same circumferential angle direction and the same radius, denoted as upper temperature measuring point Bk and lower temperature measuring point Bn. The temperature of the molten iron erosion line is set. Taking the upper temperature measuring point Bk as a reference, starting from the first or zth brick layer of the furnace bottom, it is assumed that the upper surface of the first or zth brick layer is the location of the molten iron erosion line. Then the temperature of the upper surface of the first or zth brick layer of the furnace bottom is the temperature of the molten iron erosion line.

[0047] When the surface temperature of the first layer of bricks at the bottom of the furnace is the erosion line temperature of molten iron, the heat transfer in the vertical direction of the furnace bottom is regarded as a one-dimensional steady-state heat transfer. Based on the heat flow being transferred downward from the first layer of bricks, the heat flow intensity and the surface temperature of any layer of bricks above the upper temperature measuring point Bk are obtained through calculation.

[0048] In this invention, the first layer of bricks at the bottom of the furnace is the first layer from top to bottom in the height direction, and the second layer of bricks is the layer of bricks below the first layer of bricks.

[0049] In this invention, the blast furnace preferably includes a blast furnace for smelting vanadium-titanium magnetite.

[0050] In this invention, the set temperature of the molten iron erosion line is preferably 1150°C.

[0051] In this invention, z is preferably greater than 1 and less than the brick layer where Bk is located.

[0052] In this invention, the heat flow is preferably transferred from the first layer of bricks to the upper layer temperature measuring points sequentially from top to bottom. The calculation formula for the heat flow intensity in step 1) is shown in formula (I):

[0053]

[0054] Where, λ ave The preferred value is the average thermal conductivity of the brick layer from the first layer of bricks to the brick layer containing the upper temperature measuring point Bk; X is preferably the total thickness of the brick layer from the first layer of bricks to the brick layer containing the upper temperature measuring point Bk, preferably in meters (m); t0 is preferably the temperature of the molten iron erosion line, preferably in degrees Celsius (°C); t k q represents the temperature at the upper temperature measurement point Bk, preferably in °C; q represents the heat flux intensity.

[0055] In this invention, the preferred formula for calculating the surface temperature of any brick layer above the upper temperature measuring point Bk is as shown in formula (II):

[0056]

[0057] Specifically, there is i layers of bricks between the first layer of bricks and the layer containing the upper temperature measuring point Bk, and the thickness of each layer of bricks is preferably X. i The thermal conductivity of each layer of bricks is preferably λ. i The preferred surface temperature of each layer of bricks is t. i q represents the heat flux intensity.

[0058] In this invention, formula (II) is specifically an iterative calculation formula, which is calculated using the relationship between t0-t1 and t1-t2, and so on, until t k-1 -t k Alternatively, it can be shown as follows:

[0059]

[0060] In this invention, the heat flux intensity q in formula (I) is preferably the average heat transfer intensity transferred from the surface of the first layer of bricks to the upper layer temperature measuring point Bk;

[0061] In this invention, the heat flux intensity q in formula (II) is preferably the precise heat transfer heat flux intensity transferred from the surface of the first layer of bricks to the surface of the next layer of bricks;

[0062] In this invention, the precise heat transfer flux intensity is preferably used to calibrate the average heat transfer flux intensity.

[0063] Based on the heat flux intensity obtained in the above steps, this invention further calculates the surface temperature t of each brick layer below the brick layer where the upper temperature measurement point Bk is located. m .

[0064] In this invention, the calculation formula for the recalculation is preferably as shown in formula (III):

[0065]

[0066] Where, λ m The preferred thermal conductivity is that of each brick layer from the (k+1)th layer to the mth layer; X m The preferred thickness is the thickness of each brick layer from the (k+1)th layer to the mth layer, preferably in meters (m); t m The preferred surface temperature is the temperature of each brick layer from the (k+1)th layer to the mth layer; t k The preferred temperature is the temperature at the upper temperature measurement point Bk.

[0067] Finally, when the brick layer m is the same as the brick layer with temperature point Bn below it, the surface temperature t of the brick layer is set. m The measured temperature t at the lower temperature measurement point Bn nA comparison is made, and a judgment is made based on the comparison results. When |t m -t n If the temperature is below a certain level, the assumption of the location of the molten iron erosion line is considered accurate, and this location is taken as the opening position of the blast furnace residual iron taphole.

[0068] In this invention, the preferred temperature is 20°C.

[0069] In this invention, the comparison process preferably includes the following steps:

[0070] When t m -t n If the temperature is higher than a certain value, it indicates that the assumed location of the molten iron erosion line is far from the location of the upper temperature measuring point Bk in the brick layer, and the heat flow intensity is small. Therefore, it is assumed that the temperature of the molten iron erosion line is the upper surface temperature below the second layer of bricks, and the temperature t is recalculated according to steps (1) and (2). m Perform calculations, and then make a judgment.

[0071] In this invention, the comparison process preferably includes the following steps:

[0072] When t n -t m If the temperature exceeds a certain threshold, it indicates that the assumed location of the molten iron erosion line is close to the location of the upper temperature measuring point Bk within the brick layer, indicating a high heat flow intensity. Therefore, the bisection method is used to re-assume the location of the molten iron erosion line and move it upwards by half a brick's distance. The temperature t is then re-evaluated. m Perform calculations, and then make a judgment.

[0073] In this invention, the opening position of the blast furnace residual iron taphole preferably includes the lowest position of the residual iron taphole opening.

[0074] In this invention, the determination method preferably further includes the following verification steps:

[0075] Following steps 1) to 3), select one or more other directions, calculate the temperature measurement points of two different brick layers on the same circumferential angle direction and the same radius, obtain one or more iron erosion line positions, and then compare or verify them as the lowest position of the residual iron taphole opening.

[0076] In this invention, the determining method preferably includes the step of determining the opening direction of the residual iron tap.

[0077] In this invention, the preferred method for determining the opening direction of the residual iron outlet is to select the opening direction of the residual iron outlet in conjunction with the construction of the residual iron trench and the residual iron platform.

[0078] To complete and refine the overall technical solution and better calculate the opening position of the blast furnace residual iron taphole, the method for determining the opening position of the blast furnace residual iron taphole in vanadium-titanium magnetite smelting can specifically include the following:

[0079] The method provided by this invention is specifically implemented as follows:

[0080] (1) First, before the blast furnace is shut down for major repair, collect and confirm the thermocouple temperature detection data, the distribution location and elevation of each thermocouple, etc., and collect the type, size and heat transfer coefficient of the furnace bottom brick lining in conjunction with the blast furnace hearth design drawings.

[0081] (2) Secondly, the heat transfer from the bottom of the furnace is considered as a one-dimensional steady-state heat transfer. In the same direction, the heat flux, i.e., the heat flux intensity, is equal. Taking the center of the blast furnace hearth as the reference, two thermocouples Bk (upper layer) and Bn (lower layer) that are still working normally are selected in the same circumferential angle direction and the same radius. The temperature of the molten iron erosion line is set to 1150℃. Taking the temperature of the upper layer thermocouple Bk as a reference, it is assumed that the upper surface of the first layer of bricks at the bottom of the furnace is the location of the molten iron erosion line, i.e., the temperature of the upper surface of the first layer of bricks at the bottom of the furnace is 1150℃. The heat flow is transferred vertically from the first layer of bricks to thermocouples Bk and Bn. According to the one-dimensional steady-state heat transfer equation, the heat flux intensity transferred from the surface of the first layer of bricks to the upper layer thermocouple B1 can be calculated by formula (1).

[0082]

[0083] Where λave is the average thermal conductivity of the brick layer from the first brick layer to the layer containing thermocouple Bk, and X is the total thickness of the brick layer from the first brick layer to the layer containing thermocouple Bk, in meters. Since t0 = 1150℃, the heat flux q can be calculated given λave and X. Furthermore, to further refine the calculation of the heat flux q, it is assumed that there are i layers of bricks between the first brick layer and the layer containing thermocouple Bk, with each layer having a thickness of X. i The thermal conductivity of each brick is λ. i The surface temperature of each layer of bricks is t i .

[0084] Based on the one-dimensional steady-state heat transfer characteristics, the relationship expressed by equation (2) is given.

[0085]

[0086] According to equation (2), at t0, t k ,λ1,λ i , λ k X1, X i X kGiven the given information, the temperatures t1 and t2 on the upper and lower surfaces of each layer of brick lining can be calculated (where the surface temperature of each layer of brick, or the upper or lower surface temperature of each layer of brick, i.e., the lower surface temperature of one layer of brick is also considered as the upper surface temperature of the next layer of brick). i , and heat flux intensity q.

[0087] (3) After obtaining the heat flux intensity q, the surface temperature t of each brick layer below the brick layer where the thermocouple Bk is located can be calculated according to equation (3). m .

[0088]

[0089] (4) The temperature t of each brick layer was calculated. m Then, when the m-layer brick is the same as the brick layer where the thermocouple Bn is located, the temperature t will be... m The measured temperature t of thermocouple Bn n Compare them.

[0090] If calculating temperature t m Much greater than t n This indicates that the assumed location of the 1150℃ molten iron erosion line is far from the location of the thermocouple Bk in the brick layer, and the heat flow intensity is small, which does not match the actual situation. Therefore, we continue to assume that the 1150℃ molten iron erosion line is on the upper surface of the second brick layer, and re-adjust the temperature t according to steps (2) and (3). m Perform the calculation. And so on, when t... m Much greater than t n Then, the location of the 1150℃ molten iron erosion line was further shifted downwards, the temperature of each brick layer was calculated, and compared with the actual measured temperature of thermocouple Bn. If the calculated temperature t m Much smaller than t n This indicates that the assumed location of the 1150℃ molten iron erosion line is relatively close to the brick layer where thermocouple Bk is located, resulting in a higher heat flow intensity. Therefore, the bisection method is used to re-assume the location of the 1150℃ molten iron erosion line and move it upwards by half a brick's distance. The temperature t is then recalculated. m Perform calculations and comparisons. Thus, when |t m -t n If the value Δt is less than a certain value, it is assumed that the location of the 1150℃ molten iron erosion line is accurate. The value Δt is determined by each blast furnace in combination with its allowable error.

[0091] (5) Following the steps described above, calculate and compare the positions where the upper and lower thermocouples are still working normally in other directions with the same circumferential angle and radius to obtain the accurate position of the 1150℃ erosion line, which can be used as the lowest position of the residual iron outlet. Then, taking into account the ease of building the residual iron trench and platform, select the opening direction of the residual iron outlet to carry out the residual iron release operation.

[0092] The present invention provides a method for determining the location of the blast furnace taphole opening in vanadium-titanium magnetite smelting. This invention helps ironmaking personnel determine the erosion sites on the blast furnace bottom, accurately predict the depth of molten iron in the hearth, and the location of the taphole opening at the end of the furnace's service life. This improves the accuracy of taphole opening, reduces the safety risks associated with trial and error in taphole opening, and decreases the workload of hearth dismantling during major overhauls. Furthermore, it can be widely applied in the field of blast furnace ironmaking.

[0093] The method for determining the opening position of the blast furnace residual iron taphole provided by this invention is based on the blast furnace bottom brick lining structure, the heat transfer coefficient of the bottom brick lining, and the temperature monitored by thermocouples embedded in the bottom brick lining, and applies a one-dimensional steady-state heat transfer equation. The method involves assuming the depth of molten iron erosion and calculating it, then comparing it with the operating thermocouple temperature. Through a cycle of assumption, calculation, comparison, and re-assumption, the remaining thickness of the brick lining is calculated. This invention is applicable to blast furnaces where ≥3 layers of thermocouples are embedded in the bottom brick lining of the hearth, and 1 layer of thermocouples is embedded in the furnace foundation below the hearth. In these furnaces, the thermocouples in each layer of the bottom brick lining are distributed at a consistent angle in the circumferential direction, and the insertion depth of different layers of thermocouples is consistent in the radial direction. The bottom brick lining is composed of composite mullite bricks, dense clay bricks, semi-graphite carbon bricks, or carbon bricks. The calculation method provided by this invention can more accurately calculate the erosion of the bottom brick lining by molten iron and the location of the blast furnace residual iron taphole opening.

[0094] To further illustrate the present invention, the following describes in detail a method for determining the opening position of the blast furnace residual iron taphole provided by the present invention with reference to embodiments. However, it should be understood that these embodiments are implemented under the premise of the technical solution of the present invention, and detailed implementation methods and specific operation processes are given only to further illustrate the features and advantages of the present invention, and are not intended to limit the claims of the present invention. The scope of protection of the present invention is not limited to the following embodiments.

[0095] Example 1

[0096] Blast furnace A, which uses vanadium-titanium magnetite as its main raw material, has been in service for more than 16 years. Considering the safety of production, it has been decided to shut down the furnace for a major overhaul. It is estimated that the amount of residual iron in the hearth will reach 400 to 500 tons.

[0097] Blast furnace A has a total of 9 layers of bricks at the bottom, with a total thickness of 3.60m. A thermocouple was embedded on the lower surface of the 3rd, 5th, and 7th layers of bricks at the bottom. Before the overhaul shutdown, the thermocouples on the lower surface of the 5th and 7th layers of bricks were still working normally in three directions. To accurately determine the location of the residual iron taphole opening, the erosion depth of the hearth was calculated by referring to the formulas proposed by the former Ministry of Metallurgical Industry's furnace body investigation group (X=k×d×lg(t0 / t), Anshan Iron and Steel Plant's formula (L=(1 / N)×(1350-t), and Moisenk's calculation formula (X=d / k×1 / u×lg(t1 / t)). The minimum erosion values ​​were 1.008m, 1.174m, and 1.257m, respectively, and the maximum values ​​were 1.68m, 1.492m, and 1.579m, respectively. The average erosion thicknesses were 1.316m, 1.333m, and 1.398m, respectively. There were significant differences between the maximum and minimum values ​​of the various calculation results.

[0098] Before shutdown, the erosion lines at 1150℃ in three locations of blast furnace A were calculated using the method of this invention. The erosion locations were all in the upper part of the fifth layer of bricks at the bottom of the furnace, meaning the distance between the erosion line and the upper surface of the first layer of bricks at the bottom was 1.6–1.8 m. Considering that blast furnace A was two years beyond its design life, the dead iron layer was deeper, and the molten iron erosion depth was deeper than other blast furnaces in the past, the height of the residual iron tapping point was set at 1.6 m, and 550 tons of residual iron were released during the tapping process. During the overhaul, a survey of the hearth and bottom damage was conducted, revealing that the bottom erosion was "bowl-shaped." Residual iron tapping was relatively successful, with very little residual iron remaining in the hearth. The bottom erosion line was located precisely at the fifth layer of bricks at the bottom, with only the center of the hearth reaching the lower edge of the fifth layer of bricks. This verified that the method of this invention is quite accurate in determining the location of the residual iron tapping point.

[0099] The present invention provides a detailed description of a method for determining the opening position of the blast furnace residual iron taphole in vanadium-titanium magnetite smelting. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of these embodiments are merely for the purpose of helping to understand the method and core ideas of the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those skilled in the art, several improvements and modifications can be made to the invention without departing from the principles of the invention, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements that are not different from the wording of the claims, or if they include equivalent structural elements that are not substantially different from the wording of the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A method for determining the opening position of the blast furnace residual iron taphole, characterized in that, Includes the following steps: 1) Taking the center of the blast furnace hearth as a reference, select two temperature measurement points of different brick layers in the same circumferential angle direction and the same radius, and denot them as upper temperature measurement point Bk and lower temperature measurement point Bn. Set the temperature of the molten iron erosion line. Taking the upper temperature measurement point Bk as a reference, start from the first or zth brick of the furnace bottom and assume that the upper surface of the first or zth brick is the location of the molten iron erosion line. Then the temperature of the upper surface of the first or zth brick of the furnace bottom is the temperature of the molten iron erosion line. When the surface temperature of the first layer of bricks at the bottom of the furnace is the erosion line temperature of molten iron, the heat transfer in the vertical direction of the bottom of the furnace is regarded as a one-dimensional steady-state heat transfer. Based on the heat flow from the first layer of bricks downwards, the heat flow intensity and the surface temperature of any layer of bricks above the upper temperature measurement point Bk are obtained through calculation. The heat flow is transferred sequentially from the first layer of bricks to the upper layer temperature measuring points from top to bottom. The calculation formula for the heat flow intensity in step 1) is shown in formula (I): （I）； Where, λ ave t0 is the average thermal conductivity of the brick layer from the first layer to the upper temperature measuring point Bk; X is the total thickness of the brick layer from the first layer to the upper temperature measuring point Bk, in meters; t0 is the temperature of the molten iron erosion line, in degrees Celsius; t0 is the temperature of the molten iron erosion line. k q represents the temperature at the upper temperature measurement point Bk, in °C; q represents the heat flux intensity. The formula for calculating the surface temperature of any brick layer above the upper temperature measuring point Bk is shown in formula (II): (II); Specifically, there is i layers of bricks between the first layer of bricks and the layer containing the upper temperature measuring point Bk, with each layer having a thickness of X. i The thermal conductivity of each layer of bricks is λ. i The surface temperature of each layer of bricks is t i q represents the heat flux intensity; 2) Based on the heat flux intensity obtained in the above steps, the surface temperature t of each brick layer below the brick layer where the upper temperature measurement point Bk is located is calculated again. m ; The calculation formula for the recalculation is shown in formula (III): (III); Where, λ m X represents the thermal conductivity of each brick layer from the (k+1)th layer to the mth layer; m t represents the thickness of each brick layer from the (k+1)th layer to the mth layer, in meters. m t represents the surface temperature of each brick layer from the (k+1)th layer to the mth layer; k The temperature at the upper temperature measuring point Bk; 3) When the brick layer m is the same as the brick layer with temperature point Bn below it, the surface temperature t of the brick layer is set. m The measured temperature t at the lower temperature measurement point Bn n A comparison is made, and a judgment is made based on the comparison results. When |t m -t n If the temperature is below a certain level, the assumption of the location of the molten iron erosion line is considered accurate, and this location is taken as the opening position of the blast furnace residual iron taphole.

2. The determination method according to claim 1, characterized in that, The blast furnace includes one used for smelting vanadium-titanium magnetite.

3. The determination method according to claim 1, characterized in that, The set temperature for the molten iron erosion line is specifically 1150℃.

4. The determination method according to claim 1, characterized in that, The brick layer where z is greater than 1 and less than Bk.

5. The determination method according to claim 1, characterized in that, In the formula (I), the heat flux intensity q is the average heat transfer intensity transferred from the surface of the first layer of bricks to the upper layer temperature measuring point Bk.

6. The determination method according to claim 1, characterized in that, The heat flux intensity q in the formula (II) is the precise heat transfer intensity transferred from the surface of the first layer of bricks to the surface of the next layer of bricks.

7. The determination method according to claim 1, characterized in that, The specified temperature is 20℃; The comparison process includes the following steps: When t m -t n If the temperature is higher than a certain value, it indicates that the assumed location of the molten iron erosion line is far from the location of the upper temperature measuring point Bk in the brick layer, and the heat flow intensity is small. Therefore, it is assumed that the temperature of the molten iron erosion line is the upper surface temperature below the second layer of bricks, and the temperature t is recalculated according to steps (1) and (2). m Perform calculations, and then make a judgment.

8. The determination method according to claim 1, characterized in that, The comparison process also includes the following steps: When t n -t m If the temperature exceeds a certain threshold, it indicates that the assumed location of the molten iron erosion line is close to the location of the upper temperature measuring point Bk within the brick layer, indicating a high heat flow intensity. Therefore, the bisection method is used to re-assume the location of the molten iron erosion line and move it upwards by half a brick's distance. The temperature t is then re-evaluated. m Perform calculations, and then make a judgment.

9. The determination method according to claim 1, characterized in that, The location of the blast furnace residual iron taphole opening includes the lowest point of the residual iron taphole opening; The determination method further includes the following verification steps: Following steps 1) to 3), select one or more other directions, calculate the temperature measurement points of two different brick layers on the same circumferential angle direction and the same radius, obtain one or more iron erosion line positions, and then compare or verify them as the lowest position of the residual iron taphole opening.

10. The determination method according to claim 1, characterized in that, The method for determining the iron residue tap also includes the step of determining the opening direction of the iron residue tap. The specific method for determining the opening direction of the residual iron outlet involves selecting the opening direction of the residual iron outlet based on the construction of the residual iron trench and the residual iron platform.

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