Method for determining opening position of residual iron notch of blast furnace for smelting vanadium titano-magnetite

Abstract

The invention provides a method for determining the opening position of a residual iron notch of a blast furnace. According to the method, on the basis of a blast furnace bottom brick lining structure, a furnace bottom brick lining heat transfer coefficient and the monitoring temperature of a thermocouple embedded in a furnace bottom brick lining, calculation is carried out by applying a one-dimensional steady-state heat transfer equation # imgabs0 # and assuming the erosion depth of molten iron, and then the temperature is compared with the temperature of a working thermocouple, so that in the circulating process of assumption-calculation-comparison-re-assumption, the temperature of the furnace bottom brick lining is calculated; and calculating to obtain the residual thickness of the brick lining. The method is applicable to a blast furnace in which more than or equal to three layers of temperature thermocouples are embedded in a hearth bottom brick lining and one layer of temperature thermocouples are embedded in a furnace bottom lower furnace foundation, the distribution angles of the thermocouples in each layer in the hearth bottom brick lining are consistent in the circumferential direction, and the insertion depths of the thermocouples in different layers are consistent in the radius direction. According to the method, the erosion condition of molten iron to the furnace bottom brick lining and the opening position of the blast furnace residual iron notch can be calculated more accurately.

Description

Technical Field

[0001] The invention belongs to the technical field of calculating the opening position of a blast furnace residual iron mouth for smelting vanadium-titanium magnetite, and relates to a method for determining the opening position of a blast furnace residual iron mouth, and in particular to a method for determining the opening position of a blast furnace residual iron mouth for smelting vanadium-titanium magnetite. Background Art

[0002] For blast furnace smelting, the working environment of the hearth area is very harsh. It is immersed in high-temperature slag iron for a long time, and is under the heavy pressure of thousands of tons of ore coke columns. The service life of the hearth directly determines the overall life of the blast furnace. During the normal production and smelting process of the blast furnace, the hearth and bottom brick lining are long-term eroded by molten iron penetration, metal erosion such as potassium, sodium, lead, and zinc, erosion by molten iron circulation, and thermal stress damage. In the process of pursuing blast furnace production efficiency and reducing energy consumption per ton of iron production, higher smelting intensity often accelerates the erosion and damage of the hearth and bottom brick lining. Molten iron gradually penetrates into the bottom brick lining, causing the temperature of the blast furnace bottom to rise. Once the erosion exceeds the safety limit, the hearth is at risk of burning through. Therefore, when the bottom brick lining of the hearth is eroded to a certain extent, the blast furnace can no longer continue to produce safely, and the service life of the blast furnace generation is terminated. However, whether the furnace hearth is in normal use and reaches the design life of the blast furnace, or the furnace hearth erosion accelerates and the use of the blast furnace is terminated in advance, before the furnace is shut down for overhaul, since the center line of the blast furnace iron mouth is higher than the dead iron layer of the furnace hearth, it is necessary to find a suitable opening position for the residual iron mouth to release the hundreds or thousands of tons of high-temperature molten iron accumulated below the center line of the iron mouth in the furnace hearth, so as to safely remove the brick lining of the furnace hearth furnace bottom after the furnace is shut down. If the residual iron mouth is not in a good position, it will lead to unsmooth discharge of residual iron, and more residual iron will continue to remain in the furnace hearth, which will not only reduce the safety of the furnace hearth furnace bottom removal process, but also increase the workload. Especially for blast furnaces smelting vanadium-titanium magnetite, due to the formation of high-melting-point titanium carbonitride and the furnace protection function, the hardness of the sediments containing more titanium carbonitride is higher, which will greatly increase the difficulty of subsequent construction and the investment in manpower and cost.

[0003] At present, before the blast furnace is shut down for overhaul and the residual iron is placed, the main methods for determining the residual iron mouth position are measurement method and empirical formula calculation method. The measurement method is mainly a method for measuring the furnace shell temperature. Thermocouples are inserted at different elevations of the furnace bottom to measure the highest temperature elevation of the furnace shell, thereby determining the residual iron mouth position elevation. Combined with the convenience of arranging the residual iron ditch and the residual iron placement platform, the residual iron mouth opening orientation is determined. This method is more suitable for ordinary ore smelting blast furnaces that are easily affected by molten iron circulation erosion and the furnace bottom is prone to "garlic-shaped" or "elephant-foot-shaped" erosion. The part with the highest furnace shell temperature is often the part 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 takes the form of a "bottom of the pot". Due to the influence of different thicknesses of the remaining brick lining in the circumferential direction on heat transfer, the part with the highest furnace skin temperature is not necessarily the lowest part where the residual iron is retained. Therefore, when overhauling a blast furnace smelting vanadium-titanium magnetite, most of the time, the residual iron mouth position elevation is determined by an empirical formula calculation method. The main calculation formulas refer to the formula X=k×d×lg(t0 / t) proposed by the furnace body investigation team of the former Ministry of Metallurgy, the formula L=(1 / N)×(1350-t) proposed by Anshan Iron and Steel Plant, and the Moisenk calculation formula X=d / k×1 / u×lg(t1 / t). Since these empirical formulas are often summarized from blast furnaces smelting ordinary ores, the calculation results often differ greatly from the final actual results during application.

[0005] Therefore, how to find a more accurate method to determine the position of the residual iron mouth of the blast furnace and solve the technical problems existing in the above methods is very important for the blast furnace smelting of vanadium-titanium magnetite. It is also one of the problems that many front-line researchers and blast furnace smelting companies 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 residual iron hole of a blast furnace, in particular, a method for determining the opening position of the residual iron hole of a blast furnace for smelting vanadium-titanium magnetite. 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 residual iron hole of the blast furnace, improve the accuracy of the residual iron hole opening, and can be promoted and applied in the field of blast furnace ironmaking.

[0007] The present invention provides a method for determining the opening position of a residual iron hole of a blast furnace, comprising the following steps:

[0008] 1) Taking the center of the blast furnace hearth as the reference, select two temperature measuring points of different brick layers at the same circumferential angle direction and the same radius, record them as the upper temperature measuring point Bk and the lower temperature measuring point Bn, set the molten iron corrosion line temperature, take the upper temperature measuring point Bk as the reference, start from the first layer of bricks or the zth layer of bricks at the bottom of the furnace and assume that the upper surface of the first layer of bricks or the zth layer of bricks is the location of the molten iron corrosion line, then the upper surface temperature of the first layer of bricks or the zth layer of bricks at the bottom of the furnace is the molten iron corrosion line temperature;

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

[0010] 2) Based on the heat flux intensity obtained in the above steps, calculate again from the brick layer where the upper temperature measurement point Bk is located to obtain the surface temperature t of each brick layer below the brick layer where Bk is locatedm ;

[0011] 3) When the brick layer m is the same as the brick layer where the temperature point Bn is located, the surface temperature of the brick layer t m The measured temperature t of the lower temperature measuring point Bn n Compare and judge based on the comparison results. m -t n |When the temperature is lower than a certain level, the assumption of the position of the molten iron erosion line is considered to be accurate, and this position is used as the opening position of the residual iron mouth of the blast furnace.

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

[0013] The set iron erosion line temperature is specifically 1150°C;

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

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

[0016]

[0017] Among them, λ ave is the average thermal conductivity of the brick layer from the first brick layer to the upper brick layer where the temperature measuring point Bk is located; X is the total thickness of the brick layer from the first brick layer to the upper brick layer where the temperature measuring point Bk is located, in m; t0 is the temperature of the molten iron corrosion line, in °C; t k is the temperature of the upper temperature measuring point Bk, in °C; q is the heat flux intensity.

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

[0019]

[0020] It is assumed that there are i layers of bricks between the first layer of bricks and the upper layer where the temperature measurement point Bk is located, and the thickness of each layer of bricks is 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 is the heat flux intensity.

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

[0022] The heat flux intensity q in the formula (II) is the precise 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 heat flux intensity is used to calibrate the average heat transfer heat flux intensity.

[0024] Preferably, the recalculated formula is as shown in formula (III):

[0025]

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

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

[0028] The comparison process includes the following steps:

[0029] When t m -t n When it is greater than a certain temperature, it indicates that the assumed iron corrosion line is far from the brick layer where the upper temperature measuring point Bk is located, and the heat flux intensity is small. Then, we continue to assume that the iron corrosion line temperature is the upper surface temperature below the second brick layer, and recalculate the temperature t according to steps (1) and (2). m Calculate and then judge.

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

[0031] When t n -t m When the temperature is greater than a certain value, it indicates that the assumed position of the molten iron corrosion line is close to the brick layer where the upper temperature measuring point Bk is located, and the heat flux intensity is large. In this case, the binary method is used to re-assume the position of the molten iron corrosion line and move it up by 1 / 2 brick, and re-calculate the temperature t m Calculate and then judge.

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

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

[0034] According to steps 1) to 3), one or more of the other directions are selected to calculate the temperature measuring points of two different brick layers at the same circular angle direction and the same radius to obtain one or more molten iron erosion line positions, which are then compared or verified as the lowest position of the residual iron mouth opening.

[0035] Preferably, the determination method further comprises the step of determining the opening direction of the residual iron hole;

[0036] The determining of the opening direction of the scrap iron opening is specifically to select the opening direction of the scrap iron opening in combination with the construction conditions of the scrap iron ditch and the scrap iron platform.

[0037] The present invention provides a method for determining the opening position of a residual iron mouth of a blast furnace, comprising the following steps: first, taking the center of the blast furnace hearth as a reference, selecting temperature measuring points of two different brick layers at the same circumferential angle direction and the same radius, recording them as the upper temperature measuring point Bk and the lower temperature measuring point Bn, setting the temperature of the molten iron erosion line, taking the upper temperature measuring point Bk as a reference, starting from the first layer of bricks or the zth layer of bricks at the bottom of the furnace, assuming that the upper surface of the first layer of bricks or the zth layer of bricks is the location of the molten iron erosion line, then the first layer of bricks or the zth layer of bricks at the bottom of the furnace is set to the temperature of the molten iron erosion line. The upper surface temperature of the z-th layer of bricks is the molten iron corrosion line temperature; when the upper surface temperature of the first layer of bricks at the furnace bottom is the molten iron corrosion line temperature, the heat transfer in the vertical direction of the furnace bottom is regarded as a one-dimensional steady-state heat transfer, and the heat flux is transferred downward from the first layer of bricks. After calculation, the heat flux intensity and the surface temperature of any brick layer above the upper temperature measuring point Bk are obtained; then, based on the heat flux intensity obtained in the above steps, the brick layer where the upper temperature measuring point Bk is located is calculated again to obtain the surface temperature t of each brick layer below the brick layer where Bk is located. m ; Finally, when the brick layer m is the same as the brick layer where the temperature point Bn is located, the surface temperature of the brick layer t m The measured temperature t of the lower temperature measuring point Bn n Compare and judge based on the comparison results. m -t n |After the temperature is less than a certain temperature, the assumption of the position of the molten iron erosion line is considered to be accurate, and this position is used as the position of the residual iron mouth opening of the blast furnace. Compared with the prior art, the present invention specially designs a method for determining the position of the residual iron mouth opening of the blast furnace, which is a method for determining the position of the residual iron mouth opening of the blast furnace for smelting vanadium-titanium magnetite. The present invention can help ironmaking production personnel determine the erosion position of the blast furnace bottom, accurately infer the depth position of the molten iron in the furnace and the position of the residual iron mouth opening at the end of the furnace campaign, improve the accuracy of the residual iron mouth opening, reduce the safety risks caused by trial and error of the residual iron mouth opening, reduce the workload of overhauling and dismantling the furnace, and can be promoted and applied in the field of blast furnace ironmaking.

[0038] The method for determining the opening position of the residual iron hole of a blast furnace provided by the present invention is based on the blast furnace bottom brick lining structure, the heat transfer coefficient of the furnace bottom brick lining, and the temperature monitored by the thermocouple buried in the furnace bottom brick lining. The calculation is performed by assuming the erosion depth of the molten iron, and then comparing it with the working thermocouple temperature, so that in the cycle of assumption-calculation-comparison-assumption, the remaining thickness of the brick lining is calculated. The present invention is applicable to blast furnaces with ≥3 layers of temperature measuring thermocouples buried in the brick lining at the bottom of the furnace and 1 layer of temperature measuring thermocouples buried in the furnace foundation at the bottom of the furnace, the distribution angle of each layer of thermocouples in the circumferential direction of the brick lining at the bottom of the furnace is consistent, and the insertion depth of thermocouples in different layers of thermocouples in the radial direction is consistent; the furnace bottom brick lining is composed of composite mullite bricks, dense clay bricks, semi-graphite carbon bricks or carbon bricks. The calculation method provided by the present invention can more accurately calculate the erosion of the furnace bottom brick lining by molten iron, as well as the opening position of the residual iron mouth of the blast furnace. DETAILED DESCRIPTION

[0039] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention rather than limiting the patent claims of the present invention.

[0040] All noun expressions and abbreviations in the present invention are conventional noun expressions and abbreviations in the field. Each noun expression and abbreviation is clear and unambiguous in its relevant application field. Those skilled in the art can clearly, accurately and uniquely understand them based on the noun expressions and abbreviations.

[0041] The present invention provides a method for determining the opening position of a residual iron hole of a blast furnace, comprising the following steps:

[0042] 1) Taking the center of the blast furnace hearth as the reference, select two temperature measuring points of different brick layers at the same circumferential angle direction and the same radius, record them as the upper temperature measuring point Bk and the lower temperature measuring point Bn, set the molten iron corrosion line temperature, take the upper temperature measuring point Bk as the reference, start from the first layer of bricks or the zth layer of bricks at the bottom of the furnace and assume that the upper surface of the first layer of bricks or the zth layer of bricks is the location of the molten iron corrosion line, then the upper surface temperature of the first layer of bricks or the zth layer of bricks at the bottom of the furnace is the molten iron corrosion line temperature;

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

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

[0045] 3) When the brick layer m is the same as the brick layer where the temperature point Bn is located, the surface temperature of the brick layer t m The measured temperature t of the lower temperature measuring point Bnn Compare and judge based on the comparison results. m -t n |When the temperature is lower than a certain level, the assumption of the position of the molten iron erosion line is considered to be accurate, and this position is used as the opening position of the residual iron mouth of the blast furnace.

[0046] The present invention firstly takes the center of the blast furnace hearth as a reference, selects temperature measuring points of two different brick layers at the same circumferential angle direction and the same radius, and records them as the upper temperature measuring point Bk and the lower temperature measuring point Bn, sets the temperature of the molten iron corrosion line, takes the upper temperature measuring point Bk as a reference, and starts from the first layer of bricks or the zth layer of bricks at the bottom of the furnace, assuming that the upper surface of the first layer of bricks or the zth layer of bricks is the location of the molten iron corrosion line, then the upper surface temperature of the first layer of bricks or the zth layer of bricks at the bottom of the furnace is the molten iron corrosion line temperature;

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

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

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

[0050] In the present invention, the set molten iron corrosion line temperature is preferably 1150°C.

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

[0052] In the present invention, the heat flux is preferably transferred from the first layer of bricks to the upper temperature measuring points from top to bottom in sequence, and the calculation formula of the heat flux intensity in step 1) is shown in formula (I):

[0053]

[0054] Among them, λ ave Preferably, it is the average thermal conductivity of the brick layer from the first brick layer to the brick layer where the upper temperature measuring point Bk is located; X is preferably the total thickness of the brick layer from the first brick layer to the brick layer where the upper temperature measuring point Bk is located, and the unit is preferably m; t0 is preferably the molten iron corrosion line temperature, and the unit is preferably ℃; t k is the temperature of the upper temperature measuring point Bk, preferably in °C; q is the heat flux intensity.

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

[0056]

[0057] It is assumed that there are i layers of bricks between the first layer of bricks and the upper layer of the 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 surface temperature of each layer of bricks is preferably t i ; q is the heat flux intensity.

[0058] In the present invention, the formula (II) is specifically an iterative calculation formula, which is calculated by the relationship between t0-t1 and the relationship between t1-t2, and then continues until t k-1 -t k , or as follows:

[0059]

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

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

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

[0063] Based on the heat flux intensity obtained in the above steps, the present invention calculates again from the brick layer where the upper temperature measuring point Bk is located to obtain the surface temperature t of each brick layer below the brick layer where Bk is located. m .

[0064] In the present invention, the recalculated formula is preferably as shown in formula (III):

[0065]

[0066] Among them, λ m Preferably, the thermal conductivity of each brick layer from the k+1th brick layer to the mth brick layer; X m Preferably, the thickness of each brick layer from the k+1th brick layer to the mth brick layer, preferably in m; t m Preferably, the surface temperature of each brick layer from the k+1th brick layer to the mth brick layer; t k Preferably, it is the temperature of the upper temperature measuring point Bk.

[0067] Finally, when the brick layer m is the same as the brick layer where the temperature point Bn is located in the lower layer, the surface temperature of the brick layer t m The measured temperature t of the lower temperature measuring point Bn nCompare and judge based on the comparison results. m -t n |When the temperature is lower than a certain level, the assumption of the position of the molten iron erosion line is considered to be accurate, and this position is used as the opening position of the residual iron mouth of the blast furnace.

[0068] In the present invention, the certain temperature is preferably 20°C.

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

[0070] When t m -t n When it is greater than a certain temperature, it indicates that the assumed iron corrosion line is far from the brick layer where the upper temperature measuring point Bk is located, and the heat flux intensity is small. Then, we continue to assume that the iron corrosion line temperature is the upper surface temperature below the second brick layer, and recalculate the temperature t according to steps (1) and (2). m Calculate and then judge.

[0071] In the present invention, the comparison process preferably further comprises the following steps:

[0072] When t n -t m When the temperature is greater than a certain value, it indicates that the assumed position of the molten iron corrosion line is close to the brick layer where the upper temperature measuring point Bk is located, and the heat flux intensity is large. In this case, the binary method is used to re-assume the position of the molten iron corrosion line and move it up by 1 / 2 brick, and re-calculate the temperature t m Calculate and then judge.

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

[0074] In the present invention, the determination method preferably further comprises the following verification steps:

[0075] According to steps 1) to 3), one or more of the other directions are selected to calculate the temperature measuring points of two different brick layers at the same circular angle direction and the same radius to obtain one or more molten iron erosion line positions, which are then compared or verified as the lowest position of the residual iron mouth opening.

[0076] In the present invention, the determination method preferably further comprises the step of determining the opening direction of the residual iron mouth.

[0077] In the present invention, the determining of the opening direction of the scrap iron opening is preferably performed by selecting the opening direction of the scrap iron opening in combination with the construction conditions of the scrap iron groove and the scrap iron platform.

[0078] The present invention is to complete and refine the overall technical solution, and better calculate the opening position of the residual iron hole. The above-mentioned method for determining the opening position of the residual iron hole of the blast furnace for smelting vanadium-titanium magnetite may specifically include the following contents:

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

[0080] (1) First, before the blast furnace is shut down for overhaul, collect and confirm the thermocouple temperature detection data of the blast furnace hearth that is still working normally, the distribution position and elevation of each thermocouple, and collect the type, size and heat transfer coefficient of the furnace bottom brick lining in combination with the blast furnace hearth design drawings.

[0081] (2) Secondly, the heat transfer from the furnace bottom downward is regarded as one-dimensional steady-state heat transfer. In the same direction, the heat flux, that is, 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 at the same circular angle direction and the same radius. The temperature of the molten iron corrosion line is set to 1150℃, and the temperature of the upper thermocouple Bk is used as a reference. Starting from the first layer of bricks at the bottom of the furnace, it is assumed that the upper surface of the first layer of bricks is the location of the molten iron corrosion line, that is, the upper surface temperature of the first layer of bricks at the bottom of the furnace is 1150℃. The heat flux is transferred vertically from the first layer of bricks to the thermocouples Bk and Bn. According to the one-dimensional steady-state heat transfer equation, the heat flux intensity from the surface of the first layer of bricks to the upper thermocouple B1 can be calculated by formula (1).

[0082]

[0083] Among them, λave is the average thermal conductivity of the brick layer from the first brick layer to the brick layer where the thermocouple Bk is located, and X is the total thickness of the brick layer from the first brick layer to the brick layer where the thermocouple Bk is located, in m. Since t0 = 1150 ° C, the heat flux q can be calculated when λave and X are known. At the same time, in order to further refine the calculation result of the heat flux q, it is assumed that there are i layers of bricks between the first brick layer and the brick layer where the thermocouple Bk is located, and the thickness of each layer of bricks is X. i , the thermal conductivity of each brick is λ i , the surface temperature of each layer of bricks is t i .

[0084] According to the one-dimensional steady-state heat transfer characteristics, the relationship (2)

[0085]

[0086] According to formula (2), at t0, t k ,λ1,λ i , k , X1, X i , X kIf the temperature of the upper and lower surfaces of each layer of brick lining is known, the temperatures t1 and t2 can be solved. i , and the heat flux intensity q.

[0087] (3) After solving 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 formula (3): m .

[0088]

[0089] (4) Calculate the temperature t of each brick layer m After that, when the mth brick layer is the same as the brick layer where the thermocouple Bn is located, the temperature t m The measured temperature t of thermocouple Bn n for comparison.

[0090] If the temperature t is calculated m Much larger than t n , it means that the assumed 1150℃ molten iron corrosion line is far from the brick layer where the thermocouple Bk is located, and the heat flux intensity is small, which is inconsistent with the actual situation. Then continue to assume that the 1150℃ molten iron corrosion line is on the upper surface of the second brick layer, and re-calculate the temperature t according to steps (2) and (3). m Calculate. By analogy, when t m Much larger than t n When the 1150℃ molten iron corrosion line is moved further downward, the temperature of each brick layer is calculated and compared with the actual temperature measured by the thermocouple Bn. m Much smaller than t n , it means that the assumed position of the 1150℃ molten iron corrosion line is close to the brick layer where the thermocouple Bk is located, and the heat flux intensity is large. At this time, the binary method is used to re-assume the position of the 1150℃ molten iron corrosion line and move it up by 1 / 2 brick. The temperature t m Calculate and compare. In this way, when |t m -t n |After Δt is less than a certain value, it is considered that the position of the 1150℃ molten iron corrosion line is assumed to be accurate. The value Δt is determined by each blast furnace itself combined with the allowable error.

[0091] (5) According to the above steps, the positions of the upper and lower thermocouples in the same circular angle direction and the same radius where they are still working normally are calculated and compared to obtain the accurate position of the 1150°C erosion line, which can be used as the lowest position of the residual iron opening. Combined with the convenience of building the residual iron ditch and the residual iron platform, the opening direction of the residual iron opening is selected to carry out the residual iron release operation.

[0092] The above content of the present invention provides a method for determining the opening position of the residual iron mouth of a blast furnace for smelting vanadium-titanium magnetite. The present invention can help ironmaking production personnel determine the erosion position of the blast furnace bottom, accurately estimate the depth position of the molten iron in the furnace and the position of the residual iron mouth opening at the end of the furnace campaign, improve the accuracy rate of the residual iron mouth opening, reduce the safety risks caused by trial and error of the residual iron mouth opening, reduce the workload of overhauling and dismantling the furnace, and can be promoted and applied in the field of blast furnace ironmaking.

[0093] The method for determining the opening position of the residual iron hole of a blast furnace provided by the present invention is based on the blast furnace bottom brick lining structure, the heat transfer coefficient of the furnace bottom brick lining, and the temperature monitored by the thermocouple buried in the furnace bottom brick lining. The calculation is performed by assuming the erosion depth of the molten iron, and then comparing it with the working thermocouple temperature, so that in the cycle of assumption-calculation-comparison-assumption, the remaining thickness of the brick lining is calculated. The present invention is applicable to blast furnaces with ≥3 layers of temperature measuring thermocouples buried in the brick lining at the bottom of the furnace and 1 layer of temperature measuring thermocouples buried in the furnace foundation at the bottom of the furnace, the distribution angle of each layer of thermocouples in the circumferential direction of the brick lining at the bottom of the furnace is consistent, and the insertion depth of thermocouples in different layers of thermocouples in the radial direction is consistent; the furnace bottom brick lining is composed of composite mullite bricks, dense clay bricks, semi-graphite carbon bricks or carbon bricks. The calculation method provided by the present invention can more accurately calculate the erosion of the furnace bottom brick lining by molten iron, as well as the opening position of the residual iron mouth of the blast furnace.

[0094] In order to further illustrate the present invention, a method for determining the opening position of a blast furnace residual iron mouth provided by the present invention is described in detail below in combination with embodiments. However, it should be understood that these embodiments are implemented on the premise of the technical scheme of the present invention, and detailed implementation methods and specific operating procedures are given only to further illustrate the features and advantages of the present invention, rather than to limit the claims of the present invention, and the protection scope 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 a service life of more than 16 years. Considering the safety of production, it was decided to shut down the furnace for overhaul. It is estimated that the amount of residual iron in the furnace will reach 400-500t.

[0097] The bottom of blast furnace A has 9 layers of bricks with a total thickness of 3.60m. A layer of thermocouples is buried on the lower surface of the 3rd, 5th and 7th layers of bricks. Before the overhaul, the thermocouples in 3 directions up and down on the lower surface of the 5th and 7th layers of bricks were still working normally. In order to accurately determine the opening position of the residual iron mouth, the furnace erosion depth was calculated with reference to the formula X=k×d×lg(t0 / t) proposed by the furnace body investigation team of the former Ministry of Metallurgy, the formula L=(1 / N)×(1350-t) proposed by Anshan Iron and Steel Plant, and the Moisenk calculation formula X=d / k×1 / u×lg(t1 / t). The minimum values ​​of the erosion calculation results 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 thickness was 1.316m, 1.333m, and 1.398m, respectively. The maximum and minimum values ​​of the calculation results were quite different.

[0098] Before the shutdown, the method of the present invention was used to calculate the 1150℃ erosion lines at three positions of Blast Furnace A. The erosion positions were all in the middle and upper part of the fifth brick layer of the furnace bottom, that is, the distance between the erosion line and the upper surface of the first brick layer of the furnace bottom was 1.6 to 1.8 meters. After comprehensive consideration that Blast Furnace A exceeded its design life by 2 years, the dead iron layer was deeper, and the molten iron erosion depth was deeper than that of other blast furnaces in the past, the residual iron mouth position height was set at 1.6 meters, and 550 tons of residual iron was released during the residual iron discharge process. During the overhaul, the damage of the furnace hearth and furnace bottom was investigated, and it was found that the erosion of the furnace bottom was "bottom-shaped", the residual iron discharge was relatively successful, there was little residual iron in the furnace hearth, and the erosion line of the furnace bottom was exactly located at the fifth brick layer of the furnace bottom. Only the erosion depth of the center of the furnace hearth reached the lower edge of the fifth brick layer, which verified that the method of the present invention was more accurate in determining the residual iron mouth position.

[0099] The above is a detailed introduction to a method for determining the opening position of a blast furnace residual iron mouth for smelting vanadium-titanium magnetite provided by the present invention. In this article, specific examples are used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core ideas of the present invention, including the best mode, and also enables any technician in the field to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified in a number of ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements that are not different from the literal expression of the claims, or if they include equivalent structural elements that are not substantially different from the literal expression of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A method for determining the opening position of a blast furnace residual iron hole, characterized in that: The following steps are involved: 1) Taking the center of the blast furnace hearth as the reference, select two temperature measuring points of different brick layers at the same circumferential angle direction and the same radius, record them as the upper temperature measuring point Bk and the lower temperature measuring point Bn, set the molten iron corrosion line temperature, take the upper temperature measuring point Bk as the reference, start from the first layer of bricks or the zth layer of bricks at the bottom of the furnace and assume that the upper surface of the first layer of bricks or the zth layer of bricks is the location of the molten iron corrosion line, then the upper surface temperature of the first layer of bricks or the zth layer of bricks at the bottom of the furnace is the molten iron corrosion line temperature; When the upper surface temperature of the first layer of bricks at the furnace bottom is the temperature of the molten iron corrosion line, the heat transfer in the vertical direction of the furnace bottom is regarded as one-dimensional steady-state heat transfer. Based on the heat flow from the first layer of bricks downward, the heat flow intensity and the surface temperature of any brick layer above the upper temperature measurement point Bk are obtained through calculation. 2) Based on the heat flux intensity obtained in the above steps, calculate again from the brick layer where the upper temperature measurement point Bk is located to obtain the surface temperature t of each brick layer below the brick layer where Bk is located m ; 3) When the brick layer m is the same as the brick layer where the temperature point Bn is located, the surface temperature of the brick layer t m The measured temperature t of the lower temperature measuring point Bn n Compare and judge based on the comparison results. m -t n |When the temperature is lower than a certain level, the assumption of the position of the molten iron erosion line is considered to be accurate, and this position is used as the opening position of the residual iron mouth of the blast furnace.

2. The determination method according to claim 1, characterized in that: The blast furnace includes a blast furnace for smelting vanadium-titanium magnetite; The set iron erosion line temperature is specifically 1150°C; The z is greater than 1 and less than the brick layer where Bk is located.

3. The determination method according to claim 1, characterized in that: The heat flux is transferred from the first layer of bricks from top to bottom to the upper temperature measuring points in sequence. The calculation formula of the heat flux intensity in step 1) is shown in formula (I): Among them, λ ave is the average thermal conductivity of the brick layer from the first brick layer to the upper brick layer where the temperature measuring point Bk is located; X is the total thickness of the brick layer from the first brick layer to the upper brick layer where the temperature measuring point Bk is located, in m; t0 is the temperature of the molten iron corrosion line, in °C; t k is the temperature of the upper temperature measuring point Bk, in °C; q is the heat flux intensity.

4. The determination method according to claim 3, characterized in that: The calculation formula for the surface temperature of any brick layer above the upper temperature measuring point Bk is shown in formula (II): It is assumed that there are i layers of bricks between the first layer of bricks and the upper layer where the temperature measurement point Bk is located, and the thickness of each layer of bricks is 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 is the heat flux intensity.

5. The determination method according to claim 4, characterized in that: The heat flux q in the formula (I) is the average heat flux transmitted from the surface of the first layer of bricks to the upper temperature measuring point Bk; The heat flux intensity q in the formula (II) is the precise heat flux intensity transferred from the surface of the first layer of bricks to the surface of the next layer of bricks; The precise heat transfer heat flux intensity is used to calibrate the average heat transfer heat flux intensity.

6. The determination method according to claim 1, characterized in that: The calculation formula for the recalculation is shown in formula (III): Among them, λ m is the thermal conductivity of each brick layer from the k+1th brick layer to the mth brick layer; X m is the thickness of each brick layer from the k+1th brick layer to the mth brick layer, in meters; t m is the surface temperature of each brick layer from the k+1th brick layer to the mth brick layer; t k is the temperature of the upper temperature measuring point Bk.

7. The determination method according to claim 1, characterized in that: The certain temperature is 20°C; The comparison process includes the following steps: When t m -t n When it is greater than a certain temperature, it indicates that the assumed iron corrosion line is far from the brick layer where the upper temperature measuring point Bk is located, and the heat flux intensity is small. Then, we continue to assume that the iron corrosion line temperature is the upper surface temperature below the second brick layer, and recalculate the temperature t according to steps (1) and (2). m Calculate and then judge.

8. The determination method according to claim 1, characterized in that: The comparison process further includes the following steps: When t n -t m When the temperature is greater than a certain value, it indicates that the assumed position of the molten iron corrosion line is close to the brick layer where the upper temperature measuring point Bk is located, and the heat flux intensity is large. In this case, the binary method is used to re-assume the position of the molten iron corrosion line and move it up by 1 / 2 brick, and re-calculate the temperature t m Calculate and then judge.

9. The determination method according to claim 1, characterized in that: The blast furnace residual iron opening position includes the lowest position of the residual iron opening; The determination method also includes the following verification steps: According to steps 1) to 3), one or more of the other directions are selected to calculate the temperature measuring points of two different brick layers at the same circular angle direction and the same radius to obtain one or more molten iron erosion line positions, which are then compared or verified as the lowest position of the residual iron mouth opening.

10. The determination method according to claim 1, characterized in that: The determination method further comprises the step of determining the opening direction of the residual iron hole; The determining of the opening direction of the scrap iron opening is specifically to select the opening direction of the scrap iron opening in combination with the construction conditions of the scrap iron ditch and the scrap iron platform.

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