A blast furnace hearth and bottom erosion discrimination method based on new installation and old thermocouple combination

Abstract

The application provides a blast furnace hearth bottom erosion discrimination method based on new installation and old thermocouple combination, which comprises the following steps: (1) constructing a grid node according to a blast furnace structure parameter; (2) discriminating a damaged thermocouple on the grid node, and arranging a new thermocouple in a corresponding area; (3) measuring temperature data of each temperature monitoring node of the new thermocouple and the old thermocouple, and calculating temperature data of the temperature monitoring node at the corresponding damaged thermocouple by using the temperature data of the new thermocouple; and (4) establishing an area grid according to the temperature data of the temperature monitoring node in step (3), so that a hearth bottom erosion condition model is obtained. The application comprehensively considers the existing thermocouple distribution and damage condition of the hearth, reasonably arranges the arrangement points of the new thermocouple, and provides an effective shortcut for improving the long service life level of the blast furnace and guiding the safety production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of detection of the erosion of the hearth of a blast furnace, and in particular to a method for determining the erosion of the hearth of a blast furnace based on the combination of new and old thermocouples. BACKGROUND

[0002] In recent years, with the increasing size of blast furnaces, the working conditions of the hearth of a blast furnace have become more severe, and the requirements have become more stringent. The high-temperature molten iron in the blast furnace directly contacts the refractory material. As the service life of the blast furnace increases, the erosion of the refractory lining in the hearth of the blast furnace becomes more serious. Generally, thermocouples are embedded in the blast furnace during construction to detect the erosion of the hearth of the blast furnace in a timely manner. However, during the entire production process of the blast furnace, unexpected situations may cause some thermocouples to fail, resulting in a significant lack of real-time monitoring of the erosion of the hearth of the blast furnace, which becomes a safety hazard during the later production of the blast furnace.

[0003] Therefore, under the condition of the original old thermocouples of the blast furnace, it is reasonable to add new thermocouples, and to play the role of the reasonable combination of new and old thermocouples, which is of great significance for guiding the safe production of the blast furnace and improving the economic and technical indicators. SUMMARY

[0004] The present application provides a method for determining the erosion of the hearth of a blast furnace based on the combination of new and old thermocouples, which is mainly based on the principle of heat transfer to provide monitoring and forecasting functions for the hearth of a blast furnace through post-data processing.

[0005] Technical solution: In order to solve the problem that the residual thickness of the refractory material in the hearth of a blast furnace cannot be monitored in a timely manner due to the failure of some thermocouples during the service life of the blast furnace, the present application provides a method for determining the erosion of the hearth of a blast furnace based on the combination of new and old thermocouples, which includes the following steps: (1) constructing a grid node according to the structural parameters of the blast furnace; (2) identifying damaged thermocouples on the grid node and arranging new thermocouples in the corresponding area; (3) measuring the temperature data of each temperature monitoring node of the new thermocouples and the old thermocouples, and using the temperature data of the new thermocouples to calculate the temperature data of the temperature monitoring nodes at the corresponding damaged thermocouples; (4) establishing a regional grid according to the temperature data of the temperature monitoring nodes in step (3), and obtaining a model of the erosion of the hearth of the blast furnace.

[0006] Preferably, in step (4), the calculation is obtained by Fourier's law using the temperature compensation difference method to obtain the temperature t3 of the damaged thermocouple node,

[0007]

[0008] Wherein t1, t2 are the temperature at the new thermocouple node respectively, λ1, λ2 are the thermal conductivity of the new and old thermocouple contact refractory respectively, Δx1, Δx2 are the distance between temperature nodes 1, 2 and the distance between temperature nodes 2, 3 respectively

[0009] Preferably, in step (2), the new thermocouple is arranged by inserting the new thermocouple according to the staggered principle.

[0010] Preferably, the staggered principle is to arrange the new thermocouple at different depths at the same elevation or at different elevations at the same depth.

[0011] Preferably, for the double-side damaged thermocouple identified in step (2), a new thermocouple is installed on the back of the carbon brick at the original hole position of the damaged old thermocouple.

[0012] Preferably, in step (1), the grid nodes are constructed according to the structural parameters of the blast furnace, that is, the nodes information is obtained by selecting the expansion surface of the blast furnace hearth for grid division according to the size of the blast furnace.

[0013] Preferably, in step (3), the partial temperature monitoring nodes obtained by intercepting the slice are obtained, and the multiple temperature monitoring nodes are extended to the left and right directions at the elevation and extended to the up and down directions at the insertion depth to connect the various temperature monitoring nodes, thereby obtaining the two-dimensional temperature monitoring nodes of the longitudinal section and the transverse section of the blast furnace hearth.

[0014] Preferably, the method further comprises the following step (5): correcting the obtained temperature monitoring nodes with the grid node information divided in step (1) to determine whether each node is eroded and the remaining thickness of the refractory.

[0015] Preferably, the correction is to determine the positional relationship between the temperature monitoring nodes and the grid nodes of the size of the hearth; if the distance between the temperature monitoring nodes and the grid nodes is within the error allowable range then the node erosion can be directly determined by comparing the temperature field view of the hearth; if the distance between the two points exceeds the error range, the absolute distance method is used for average processing.

[0016] The beneficial effects of the present application are as follows:

[0017] The present application comprehensively considers the distribution and damage of the existing thermocouples in the hearth, and reasonably arranges the layout of the new thermocouples. The method of the present application timely restores and improves the monitoring function of the erosion condition of the side wall of the hearth, provides a strong theoretical basis for timely understanding the erosion condition of the refractory lining of the hearth bottom of the blast furnace, and provides an effective shortcut for improving the service life of the blast furnace and guiding safety production. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1A new furnace hearth and bottom erosion discrimination method combined with newly installed and old thermocouples is provided for the embodiment of the present application.

[0019] Figure 2 In the new furnace hearth and bottom erosion discrimination method combined with newly installed and old thermocouples provided for the embodiment of the present application, the thermocouple distribution diagram on the pre-installed furnace hearth development surface is shown.

[0020] Figure 3 In the new furnace hearth and bottom erosion discrimination method combined with newly installed and old thermocouples provided for the embodiment of the present application, the pre-installed thermocouple distribution diagram on the furnace hearth development surface is shown.

[0021] Figure 4 In the new furnace hearth and bottom erosion discrimination method combined with newly installed and old thermocouples provided for the embodiment of the present application, the position diagram of the newly installed thermocouple in the furnace hearth brick is shown.

[0022] Figure 5 In the new furnace hearth and bottom erosion discrimination method combined with newly installed and old thermocouples provided for the embodiment of the present application, the judgment mode diagram is shown. DETAILED DESCRIPTION

[0023] In order to better illustrate the purpose, technical scheme and advantages of the present application, the present application will be further described below in combination with specific embodiments.

[0024] Embodiment 1

[0025] The present embodiment provides a new furnace hearth and bottom erosion discrimination method based on the combination of newly installed and old thermocouples. The old thermocouple 4 (or original thermocouple) is arranged on the blast furnace body 1. The old thermocouple 4 sends a signal to the data processing unit 3. The data processing unit 3 can directly record and process the internal temperature of the blast furnace. The data processing unit 3 is an intelligent terminal such as a computer, etc., and has a data display module such as an LED display screen, etc. During the entire production process of the blast furnace, various unexpected situations may cause some thermocouples to fail. Even if a newly installed thermocouple 2 is installed in the damaged area, the newly installed thermocouple 2 and the old thermocouple 4 can send monitoring reports to the data processing unit 3, which can solve the problem of partial thermocouple failure. Preferably, the newly installed thermocouple 2 is arranged at the same elevation, different depths and / or the same depths, different elevations of the old thermocouple 4. If the old thermocouple 4 is a double-sided damaged thermocouple, the newly installed thermocouple 2 can be arranged on the back of the carbon brick at the original hole position of the old thermocouple 4.

[0026] Further, due to the large volume of the blast furnace, according to the structural parameters of the blast furnace, the blast furnace body 1 is divided into different regions to form a plurality of structural grids 5, each structural grid 5 extends in the left-right direction at the elevation and extends in the up-down direction at the insertion depth to connect to obtain the longitudinal and transverse two-dimensional structural grids of the blast furnace hearth. The old thermocouple 4 and / or the new thermocouple 2 are arranged on the nodes of the structural grid 5, which facilitates obtaining the temperature data of the structural grid 5, and connecting the longitudinal and transverse two-dimensional structural grids of the blast furnace hearth by extending in the left-right direction at the elevation and extending in the up-down direction at the insertion depth.

[0027] Embodiment 2

[0028] Based on embodiment 1, the present embodiment provides a method for identifying the erosion of the blast furnace hearth bottom based on the combination of new and old thermocouples, the blast furnace body 1 is 5800m 3 The blast furnace considers the heat transfer of the side wall of the hearth as two-dimensional heat transfer, and reasonably arranges the distribution points of the new thermocouples 2 at the same elevation and different depths and the same depth and different elevations, respectively. The bottom part is reasonably replaced according to the specific damage position of the thermocouple. The specific operation method is as follows:

[0029] First step: select the key four layers of thermocouples covering the severely eroded elephant foot area and the area near the iron notch for intensive investigation, which are at elevations of 8.59m, 9.79m, 10.99m and 12.19m, respectively.

[0030] Second step: through comprehensive analysis and statistics of the damage of the selected key four layers of thermocouples, based on two means of conventional identification and long-term experience identification: 1. Conventional identification: the obtained temperature data is lower than the normal temperature and higher than the highest threshold value, which is judged as damaged; 2. Long-term experience identification: combined with the change trend of the surrounding temperature points, such as the temperature inside the furnace body being obviously higher than the temperature outside, the temperature trend of the furnace body cannot meet the actual conditions of the blast furnace production, etc. The specific damage condition of the temperature points needs to be comprehensively analyzed and judged in combination with various conditions, and finally the damaged thermocouples (including single-sided damage and double-sided damage) in the old thermocouples 4 are identified.

[0031] Third step: insert new thermocouples 2 at the original damage thermocouple elevation according to the staggered principle, that is, set them at a position 200mm (carbon brick thickness 600mm) higher than the original elevation, mainly arrange them on the carbon brick surface on the two sides of the iron notch, and the insertion depth of the thermocouples should be determined according to the residual thickness of the side wall of the hearth (length of service life). The insertion depth of the thermocouples is 150mm (inside) to 50mm (outside). For the double-sided damaged thermocouples identified in step two, a new thermocouple 2 is installed on the back of the carbon brick at the original hole position of the damaged thermocouple. Although the thermal conductivity coefficient of the front end of the thermocouple is complex, it can at least reflect the trend of temperature change and has auxiliary monitoring effect.

[0032] Fourth step: combine heat transfer theory and difference mathematics theory, through the measurement of temperature field of newly installed thermocouple 2, use data processing unit 3 to perform inverse operation, calculate the temperature at the corresponding damaged thermocouple, based on the temperature measurement point data to calculate the steady state temperature field, the temperature distribution of the whole furnace can be obtained. Then use the temperature of each temperature measurement point to generate the overall data of the structure grid 5, then perfect the grid, through the calculation of the temperature field of the furnace shell and the furnace bottom to reflect the erosion condition of the furnace shell and the furnace bottom, the 1150℃ isotherm is the erosion reference line, the erosion condition model of the furnace shell and the furnace bottom is obtained, the specific process is as follows:

[0033] 1) According to the size of the furnace shell, the unfolded surface of the furnace shell is selected to divide the grid to obtain the node information of each structure grid 5.

[0034] 2) Take part of the slice in the furnace shell (the foot area and the area near the iron mouth where the furnace shell is seriously eroded), measure the temperature at the node of the newly installed thermocouple 2, and get the temperature t3 at the node of the damaged thermocouple by using the temperature compensation difference method according to Fourier's law,

[0035]

[0036] Wherein t1, t2 are the temperatures at the nodes of the newly installed thermocouple 2, λ1, λ2 are the thermal conductivities of the contact refractory of the new and old thermocouples, Δx1, Δx2 are the distances between temperature nodes 1, 2 and temperature nodes 2, 3 respectively. Similarly, the temperature field of the thermocouple at other positions can be obtained by using the above method.

[0037] 3) For the temperature monitoring nodes of different structure grids 5 obtained in step two, extend to the left and right directions at the elevation of the structure grid 5, extend to the up and down directions at the insertion depth, connect the temperature monitoring nodes to obtain the two-dimensional temperature monitoring nodes of the longitudinal section and the transverse section of the furnace shell.

[0038] 4) Correct the obtained temperature monitoring nodes with the previously divided grid node information, if the node temperature exceeds 1150 degrees Celsius, it is judged that erosion has occurred. If the temperature of the eroded point is lower than 1150 degrees Celsius, it is judged that the thickness of the refractory has increased, and finally it is judged whether each node has been eroded and the remaining thickness of the refractory.

[0039] The specific method for correcting the grid node information is:

[0040] (1) Judge the positional relationship between the temperature monitoring node and the grid node of the furnace shell;

[0041] (2) If the distance between the temperature monitoring node and the grid node is within the allowable error range Then directly compare the furnace temperature field view to judge whether the node has been eroded;

[0042] (3) If the distance between two points exceeds the error range, the absolute distance method is used for average processing;

[0043] 5) Set the monitoring temperature of the different structure grid 5 in the data processing unit 3, train the model, input the monitoring temperature at the new thermocouple 2, and the corresponding temperature at the damaged thermocouple and the old thermocouple 4 can be obtained. The results are fed back to the data processing unit 3, and the erosion of the different structure grid 5 can be judged. Through post-processing, a complete blast furnace hearth erosion model is formed.

[0044] Due to the complexity of the furnace conditions in the blast furnace and the particularity of the safety of maintenance, the present scheme selects the key area and uses the above-mentioned method to carry out simulation research through the data processing unit 3, and finally obtains the blast furnace hearth erosion model. As shown in Figure 1 The flowchart of the entire embodiment is shown in FIG. 1. The object foot area and the old thermocouple 4 near the iron notch area are investigated and analyzed (refer to FIG. 2). Figure 2 The thermocouple distribution diagrams at the elevations of 8.59 m, 9.79 m, 10.99 m and 12.19 m on the hearth development surface are shown in FIGS. 3, 4, 5 and 6, respectively. The damaged thermocouples are identified, and the distribution of the new thermocouples 2 is reasonably arranged. The staggered principle is adopted at the damaged thermocouple elevation, that is, the new thermocouple is inserted at a position 200 mm (carbon brick thickness 600 mm) higher than the original elevation. Figure 3 The red dot represents the position of the new thermocouple. The new thermocouples are mainly arranged on the original cold plate gap on both sides of the iron notch. In this case, the remaining thickness of the hearth erosion is considered, and the depth of the inserted thermocouple is 50 mm, as shown in Figure 4 The black dot is the position of the new thermocouple in the hearth brick.

[0045] The temperature of the damaged and old thermocouples 4 in the region is calculated through the temperature at the new thermocouple 2, the monitoring temperature of each grid node in the configuration model is obtained, the model is trained, and the monitoring temperature at the new thermocouple 2 is input. The temperature at the corresponding damaged thermocouple and the old thermocouple can be obtained. The results are fed back to the model, and a complete blast furnace hearth erosion model is formed through post-processing. Thus, the ordered linkage of the new and old thermocouples is achieved, and the monitoring function of the hearth sidewall erosion condition is restored and improved.

[0046] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A method for judging erosion of the hearth and bottom of a blast furnace based on a combination of newly installed and old thermocouples, characterized in that: Includes the following steps, (1) Construct grid nodes based on blast furnace structural parameters; (2) Identify the damaged thermocouples on the grid nodes and install new thermocouples in the corresponding areas; The installation of new thermocouples involves inserting them using a staggered seam principle. The staggered joint principle refers to the reasonable arrangement of new thermocouples at the same elevation but different depths or at the same depth but different elevations. For thermocouples that are identified as damaged on both sides, continue to install new thermocouples on the back of the carbon brick at the original hole position of the old damaged thermocouple; (3) Measure the temperature data of each temperature monitoring node of the newly added thermocouple and the old thermocouple, and use the temperature data of the newly added thermocouple to calculate the temperature data of the corresponding temperature monitoring node at the damaged thermocouple. The calculation, using Fourier's law and the temperature compensation difference method, yielded the temperature t3 at the damaged thermocouple node. ； Where t1 and t2 are the temperatures at the newly installed thermocouple nodes, λ1 and λ2 are the thermal conductivity of the contact refractory material between the old and new thermocouples, and Δx1 and Δx2 are the distances between temperature nodes 1 and 2 and between temperature nodes 2 and 3, respectively. (4) Based on the temperature data of the temperature monitoring nodes in step (3), a regional grid is established to obtain the furnace hearth and furnace bottom erosion status model; (5) Correct the obtained temperature monitoring nodes with the grid node information divided in step (1) to determine whether each node has been eroded and the remaining thickness of the refractory material; The correction is to determine the positional relationship between the temperature monitoring node and the grid nodes of the furnace hearth size; If the distance between the temperature monitoring node and the grid node is within the allowable error range If the distance between two points exceeds the error range, the absolute distance method should be used for averaging. Where δ is the allowable error threshold, and l1 and l2 are the coordinate distances between the temperature monitoring node and the grid node, respectively.

2. The blast furnace hearth and bottom erosion discrimination method based on the combination of newly installed and old thermocouples as described in claim 1, characterized in that: In step (1), the construction of grid nodes based on the blast furnace structural parameters involves selecting the hearth development surface according to the size of the blast furnace and dividing it into grids to obtain information for each node.

3. The blast furnace hearth and bottom erosion discrimination method based on the combination of newly installed and old thermocouples as described in claim 2, characterized in that: In step (3), multiple temperature monitoring nodes are obtained by cutting out some temperature monitoring nodes. The nodes are extended to the left and right at the elevation and to the up and down at the insertion depth to connect the various temperature monitoring nodes, thus obtaining two-dimensional temperature monitoring nodes in the longitudinal and transverse sections of the blast furnace hearth.

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