Method for continuously measuring temperature of molten iron in blast furnace and method for operating blast furnace

Abstract

To provide a method for continuously measuring the temperature of molten iron in a blast furnace with which the accuracy of the continuous measurement of the molten iron temperature with a radiation thermometer can be improved, and to provide a method for operating the blast furnace.SOLUTION: In the method for continuously measuring the temperature of the molten iron in the blast furnace, the temperature of the molten iron discharged from a tapping hole in the blast furnace is continuously measured by using a radiation thermometer, and the temperature of the molten iron is measured by the radiation thermometer so as to reduce the effect of dust on the temperature of the molten iron measured by the radiation thermometer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for continuously measuring the temperature of molten iron in a blast furnace and a method for operating a blast furnace. [Background technology]

[0002] Conventionally, a technique for continuously measuring the temperature of molten iron discharged from a taphole of a blast furnace involves, for example, separating the molten iron and molten slag from the features of a histogram of radiance from a radiation thermometer and analyzing only the temperature of the molten iron (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-119110 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the method of continuously measuring the molten iron temperature using a radiation thermometer has the problem that it is difficult to obtain appropriate radiance due to disturbances such as dust, which reduces the accuracy of continuous measurement of the molten iron temperature using the radiation thermometer.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method for continuously measuring the temperature of molten pig iron in a blast furnace and a method for operating a blast furnace, which can improve the accuracy of continuous measurement of the temperature of molten pig iron using a radiation thermometer. [Means for solving the problem]

[0006] In order to solve the above problems and achieve the objectives, (1) The method for continuously measuring the temperature of blast furnace molten pig iron according to the present invention is a method for continuously measuring the temperature of blast furnace molten pig iron discharged from a tap hole of a blast furnace using a radiation thermometer, characterized in that the temperature of the molten pig iron is measured by the radiation thermometer so as to reduce the effect of dust on the temperature of the molten pig iron measured by the radiation thermometer.

[0007] (2) The method for continuously measuring the temperature of blast furnace molten pig iron according to the present invention is the invention of (1) above, in which a skimmer damper is arranged in the flow path of the blast furnace main runner, which serves as a flow path for the molten pig iron and molten slag discharged from the taphole, and a molten pig iron runner into which the molten pig iron separated by the skimmer damper overflows from a rising section and flows, and a slag runner into which the molten slag separated by the skimmer damper overflows from a slag splash section and flows, are provided side by side, and a dust collector for collecting dust is arranged near the skimmer damper, and the temperature of the molten pig iron overflowing from the rising section and flowing into the molten pig iron runner is measured by the radiation thermometer downstream of the skimmer damper in the flow path of the blast furnace main runner.

[0008] (3) In the method for continuously measuring the temperature of blast furnace molten iron according to the present invention, in the invention (1) above, when the temperature of the molten iron discharged from the taphole is measured by the radiation thermometer, air is purged toward the angle of view of the radiation thermometer.

[0009] (4) The method for continuously measuring the temperature of blast furnace molten iron according to the present invention, in the above-mentioned (1), uses a two-color thermometer as the radiation thermometer, analyzes the brightness ratio of each pixel of the image of the molten iron taken by the two-color thermometer using a processing device, extracts pixels in the +2σ to +3σ interval of the standard deviation of the brightness ratio of each pixel, and averages the temperature values ​​corresponding to the brightness ratio of each extracted pixel to obtain an average temperature value as the molten iron temperature.

[0010] (5) The method for continuously measuring the temperature of blast furnace molten iron according to the present invention is any one of the inventions (1) to (4) above, in which the measured value of the molten iron measured by the radiation thermometer is corrected by the measured value of the molten iron measured by a thermocouple.

[0011] (6) The method for operating a blast furnace according to the present invention continuously measures the temperature of molten iron discharged from a taphole of a blast furnace using the method for continuously measuring the temperature of molten iron in a blast furnace according to any one of the above inventions (1) to (5). [Effects of the Invention]

[0012] The method for continuously measuring the temperature of molten pig iron in a blast furnace and the method for operating a blast furnace according to the present invention have the effect of improving the accuracy of continuous measurement of the temperature of molten pig iron using a radiation thermometer. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a cross-sectional view schematically showing an example of a blast furnace main runner through which molten iron flows, the temperature of which is measured using the method for continuously measuring the blast furnace molten iron temperature according to the first embodiment. [Figure 2] FIG. 2 is a plan view schematically showing an example of a blast furnace main runner through which molten iron flows, the temperature of which is measured using the method for continuously measuring blast furnace molten iron temperature according to the first embodiment. [Figure 3] FIG. 3 shows the results of correcting the molten iron temperature continuously measured by the two-color thermometer using the molten iron temperature measured by the thermocouple. [Figure 4] FIG. 4 is a cross-sectional view schematically showing an example of a blast furnace main runner through which molten iron flows, the temperature of which is measured using the method for continuously measuring the blast furnace molten iron temperature according to the second embodiment. [Figure 5] FIG. 5 is a diagram showing the temperature values ​​measured by the two-color thermometer with and without air purging. [Figure 6] Figure 6(a) is a histogram of the molten iron temperature measured by the two-color thermometer without air purging as shown in Figure 5. Figure 6(b) is a histogram of the molten iron temperature measured by the two-color thermometer with air purging as shown in Figure 5. [Figure 7]FIG. 7 is a cross-sectional view schematically showing an example of a blast furnace main runner through which molten iron flows, the temperature of which is measured using the method for continuously measuring the blast furnace molten iron temperature according to the third embodiment. [Figure 8] Fig. 8(a) is a graph showing the standard deviation of the luminance ratio for each pixel, and Fig. 8(b) is a graph showing the interval of +2σ to +3σ of the standard deviation of the luminance ratio for each pixel shown in Fig. 8(a). [Figure 9] Figure 9 shows various temperatures analyzed using image processing on an image of molten iron taken with a two-color thermometer. [Figure 10] FIG. 10 is a flowchart showing an example of a procedure for measuring the molten iron temperature by the method for continuously measuring the blast furnace molten iron temperature according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] (Embodiment 1) A first embodiment of the method for continuously measuring the temperature of blast furnace molten pig iron and the method for operating a blast furnace according to the present invention will be described below. However, the present invention is not limited to this embodiment.

[0015] Fig. 1 is a cross-sectional view schematically illustrating an example of a blast furnace main runner 10 through which molten iron 3 flows, the temperature of which is measured using the method for continuously measuring blast furnace molten iron temperature according to embodiment 1. Fig. 2 is a plan view schematically illustrating an example of a blast furnace main runner 10 through which molten iron 3 flows, the temperature of which is measured using the method for continuously measuring blast furnace molten iron temperature according to embodiment 1.

[0016] As shown in FIG. 1, the blast furnace main runner 10 is a channel through which molten pig iron 3 and molten slag 4 discharged from the taphole 2 of the blast furnace 1 flow downstream. The molten pig iron 3 is a molten metal whose main component is iron. The molten slag 4 is a molten oxide such as Al2O3, SiO2, or CaO. Therefore, the molten pig iron 3 and the molten slag 4 have different specific gravities and flow separately within the blast furnace main runner 10. That is, as shown in FIG. 1, the molten pig iron 3 sinks to the bottom, and the molten slag 4 floats above the molten pig iron 3 as they flow down the blast furnace main runner 10.

[0017] The molten pig iron 3 and molten slag 4 that flow down the flow path of the blast furnace main runner 10 are blocked by the skimmer damper 5. As a result, the molten slag 4 overflows from the slag splash section 6 and flows into a slag runner 9 (not shown). Meanwhile, the molten pig iron 3 passes through a gap formed between the underside of the skimmer damper 5 and the bottom surface of the blast furnace main runner 10, moves downstream of the skimmer damper 5, and then overflows from the rising section 7 and flows into the molten pig iron runner 8.

[0018] As shown in FIG. 2, a dust collection duct 40 serving as a dust collector is disposed upstream of the skimmer damper 5 in the flow path of the blast furnace main runner 10, facing the slag runner 9 across the blast furnace main runner 10. An opening 40a of the dust collection duct 40 faces the blast furnace main runner 10. An unillustrated suction device that generates an airflow for sucking dust through the opening 40a is connected to the end of the dust collection duct 40 opposite the opening 40a. The dust collection duct 40 sucks, captures, and removes dust floating around the skimmer damper 5 and fumes that may be generated when the molten pig iron 3 collides with the skimmer damper 5 through the opening 40a.

[0019] 2, a dust collection duct 41 is disposed in the flow path of the blast furnace main runner 10 near the taphole 2, with an opening 41a facing the blast furnace main runner 10. A suction device (not shown) that generates an airflow for sucking dust from the opening 41a is connected to the end of the dust collection duct 41 opposite the opening 41a. The dust collection duct 41 sucks in, captures, and removes dust floating around the taphole 2 through the opening 41a.

[0020] In the method for continuously measuring the temperature of blast furnace molten pig iron according to the first embodiment, the temperature of the molten pig iron 3 that overflows from the rising section 7 and flows into the molten pig iron runner 8 is measured downstream of the skimmer damper 5 in the flow path of the blast furnace main runner 10 by a two-color pyrometer 21, which is a radiation thermometer. The two-color pyrometer 21 measures the temperature using the ratio of radiance at two different wavelengths. The two-color pyrometer 21 continuously measures the temperature of the molten pig iron 3, for example, with a sampling period of one minute.

[0021] When measuring the molten pig iron temperature using the two-color pyrometer 21, if dust increases the scattering of light on the short wavelength side, the brightness ratio shifts to the smaller side, and the temperature measured by the two-color pyrometer 21 is output lower than the actual molten pig iron temperature. Furthermore, if light of each wavelength from the molten pig iron 3 is scattered by dust, the variation in the temperature measured by the two-color pyrometer 21 increases.

[0022] Therefore, in the method for continuously measuring the blast furnace molten pig iron temperature according to the first embodiment, the molten pig iron temperature can be measured by the two-color thermometer 21 at a position in a dusty environment with relatively little dust, far away from the taphole 2 where a relatively large amount of dust is generated in the flow path of the blast furnace main runner 10. Furthermore, in the method for continuously measuring the blast furnace molten pig iron temperature according to the first embodiment, the dust and fumes around the skimmer damper 5 are collected by the dust collection duct 40, so that the molten pig iron temperature can be measured by the two-color thermometer 21 in an environment with even less dust and fumes. As a result, in the method for continuously measuring the blast furnace molten pig iron temperature according to the first embodiment, the temperature of the molten pig iron 3 can be measured by the two-color thermometer 21 so as to reduce the influence of external disturbances such as dust on the temperature of the molten pig iron 3 measured by the two-color thermometer 21.

[0023] In the method for continuously measuring the blast furnace molten pig iron temperature according to the first embodiment, the molten pig iron temperature is measured by a thermocouple 31 downstream of the skimmer damper 5 and upstream of the rising section 7 in the flow path of the blast furnace main runner 10. The thermocouple 31 is immersed in the molten pig iron 3 through an opening 30a provided in a runner cover 30 that covers a portion of the blast furnace main runner 10. The thermocouple 31 is connected to a calculation device 32 via wiring. The calculation device 32 calculates the molten pig iron temperature based on the voltage value output from the thermocouple 31. The calculation device 32, which calculates the molten pig iron temperature measured by the thermocouple 31, is connected to a processing device 22, which calculates the molten pig iron temperature measured by the two-color thermometer 21, via wireless or wired communication. The measurement of the molten pig iron temperature by the thermocouple 31 is performed by immersing the thermocouple 31 in the molten pig iron 3 at any desired temperature measurement timing. After the measurement of the molten iron temperature by the thermocouple 31 is completed, the thermocouple 31 is pulled out from the molten iron 3. In other words, when measuring the molten iron temperature by the thermocouple 31, the molten iron temperature is not measured continuously as in the two-color thermometer 21, and therefore wear on the thermocouple 31 can be reduced.

[0024] FIG. 3 is a diagram showing the results of correcting the molten iron temperature continuously measured by the two-color thermometer 21 using the molten iron temperature measured by the thermocouple 31.

[0025] 3, the molten iron temperature measured by the two-color pyrometer 21 is calculated to be higher than the molten iron temperature measured by the thermocouple 31. Therefore, in the method for continuously measuring the blast furnace molten iron temperature according to the first embodiment, the molten iron temperature measured by the two-color pyrometer 21 is corrected based on the molten iron temperature measured by the thermocouple 31, which is considered to be less affected by disturbances than the two-color pyrometer 21.

[0026] As a method of this correction, for example, as shown in Fig. 3, the processing device 22 calculates the maximum value of the molten pig iron temperature over a five-minute period based on the molten pig iron temperature measured by the two-color pyrometer 21. Then, when the molten pig iron temperature is measured by the thermocouple 31, the maximum value of the molten pig iron temperature over a five-minute period calculated by the processing device 22 is forcibly adjusted to the molten pig iron temperature measured by the thermocouple 31. Thereafter, the difference between the measurement value of the two-color pyrometer 21 and the measurement value of the thermocouple 31 is used as a correction value to correct the molten pig iron temperature measured by the two-color pyrometer 21.

[0027] As a result, in the method for continuously measuring the blast furnace molten iron temperature according to the first embodiment, the accuracy of continuous measurement of the molten iron temperature using the two-color thermometer 21 can be improved.

[0028] (Embodiment 2) Hereinafter, a second embodiment of the method for continuously measuring the temperature of blast furnace hot metal and the method for operating a blast furnace according to the present invention will be described. Note that in the second embodiment, the same explanations as in the first embodiment will be omitted as appropriate.

[0029] FIG. 4 is a cross-sectional view schematically illustrating an example of a blast furnace main runner 10 through which molten iron flows, the temperature of which is measured using the method for continuously measuring the blast furnace molten iron temperature according to the second embodiment.

[0030] In the second embodiment, a working floor 20 is provided above the taphole 2 of the blast furnace 1, extending horizontally from the furnace wall surface. The working floor 20 has an opening 20a at a position where the jet of molten iron 3 discharged from the taphole 2 can be viewed. A two-color thermometer 21 is held by a holding member (not shown) and arranged on the working floor 20 so that the jet of molten iron 3 discharged from the taphole 2 can be photographed through the opening 20a to measure the molten iron temperature.

[0031] An opening 20b, into which part of an air purging lance 50 is inserted, is provided near the opening 20a in the work floor 20. The air purging lance 50 is used for air purging, in which air supplied from an air supply device (not shown) is sprayed from the tip to blow away and remove dust particles present on the optical path within the angle of view θ of the two-color thermometer 21 below the work floor 20.

[0032] When measuring the molten iron temperature using a two-color pyrometer 21 in the vicinity of the taphole 2 of the blast furnace 1, which is in a dusty environment, the dust significantly scatters the short-wavelength light, shifting the brightness ratio to a smaller value and causing the measured temperature to be output lower than the actual molten iron temperature. In addition, the dust scatters the light of each wavelength from the molten iron 3, resulting in large variations in the temperature measured by the two-color pyrometer 21.

[0033] Therefore, in the method for continuously measuring the temperature of blast furnace molten iron according to the second embodiment, when the jet of molten iron 3 ejected from the taphole 2 is photographed with a two-color thermometer 21 to measure the temperature of the molten iron, dust particles present on the optical path within the angle of view θ of the two-color thermometer 21 are blown away and removed by air purging.

[0034] Fig. 5 shows the temperature values ​​measured by the two-color thermometer 21 with and without air purging. Fig. 6(a) is a histogram of the temperature values ​​of the molten iron measured by the two-color thermometer 21 without air purging as shown in Fig. 5. Fig. 6(b) is a histogram of the temperature values ​​of the molten iron measured by the two-color thermometer 21 with air purging as shown in Fig. 5.

[0035] In the method for continuously measuring the blast furnace molten pig iron temperature according to the second embodiment, dust particles within the angle of view θ of the two-color thermometer 21 are blown away and removed by air injected from the tip of the air purging lance 50. That is, the air purging lance 50 injects air in the direction opposite to the direction of the jet of molten pig iron 3 ejected from the taphole 2, thereby reducing the ejection velocity of the dust particles ejected from the taphole 2 and enabling efficient dust collection. As a result, while there is a large variance in the measured temperature values ​​of the molten pig iron when measuring the temperature without air purging as shown in Figure 5(a), it is possible to reduce the variance in the measured temperature values ​​of the molten pig iron when measuring the temperature with air purging as shown in Figure 5(b). Therefore, in the method for continuously measuring the temperature of blast furnace molten iron according to the second embodiment, the accuracy of the continuous measurement of the temperature of molten iron can be improved by efficiently removing dust particles on the optical path within the angle of view θ of the two-color thermometer 21 that measures the temperature of the molten iron 3 ejected from the taphole 2 by air purging.

[0036] It is also conceivable to perform air purging by covering the optical path within the angle of view θ of the two-color thermometer 21 with a shield such as a pipe. However, the shield reduces the efficiency of work performed around the taphole 2 (e.g., slag removal work from the taphole 2). In addition, a large amount of molten iron, as well as dust, is scattered into the optical path within the angle of view θ of the two-color thermometer 21, which causes problems such as increased frequency of replacement of the shield. For this reason, injecting air with the air purging lance 50 is more effective at improving the efficiency of work performed around the taphole 2 and is also advantageous in terms of equipment maintenance than covering the optical path within the angle of view θ of the two-color thermometer 21 with a shield and performing air purging.

[0037] Furthermore, in the method for continuously measuring the blast furnace hot metal temperature according to the second embodiment, the hot metal temperature measured by the two-color thermometer 21 may be corrected based on the hot metal temperature measured by the thermocouple 31, as in the method for continuously measuring the blast furnace hot metal temperature according to the first embodiment. This makes it possible to further improve the accuracy of the continuous measurement of the hot metal temperature by the two-color thermometer 21.

[0038] (Embodiment 3) Hereinafter, a third embodiment of the method for continuously measuring the temperature of blast furnace hot metal and the method for operating a blast furnace according to the present invention will be described. Note that in the third embodiment, the same descriptions as those in the first and second embodiments will be omitted as appropriate.

[0039] FIG. 7 is a cross-sectional view schematically illustrating an example of a blast furnace main runner 10 through which molten iron flows, the temperature of which is measured using the method for continuously measuring blast furnace molten iron temperature according to the third embodiment. FIG. 8(a) is a graph showing the standard deviation of the pixel-by-pixel brightness ratio. FIG. 8(b) is a graph showing the +2σ to +3σ interval of the standard deviation of the pixel-by-pixel brightness ratio shown in FIG. 8(a). The vertical axes of FIGS. 8(a) and 8(b) are degrees. The horizontal axes of FIGS. 8(a) and 8(b) are brightness ratios, more specifically, G / R brightness ratios.

[0040] In the method for continuously measuring the temperature of blast furnace molten pig iron according to the third embodiment, as shown in Fig. 7, the jet of molten pig iron 3 ejected from the taphole 2 is photographed with a two-color thermometer 21 to measure the temperature of the molten pig iron. From the image of the molten pig iron 3 photographed with the two-color thermometer 21, pixels that are minimally affected by dust are extracted and analyzed by image processing by a processing device 22, and a value close to the true value (the temperature measured by the thermocouple 31) is calculated.

[0041] Specifically, the processing device 22 analyzes the brightness ratio of each pixel of the image using a pixel brightness ratio standard deviation filter, and calculates a graph showing the standard deviation of the pixel brightness ratio, as shown in Fig. 8(a), for example. Then, as shown in the graph of Fig. 8(b), the processing device 22 extracts pixels in the +2σ to +3σ interval of the pixel brightness ratio standard deviation, which are pixels that are least affected by dust. The temperature values ​​corresponding to the extracted pixel brightness ratios are averaged, and the average temperature value is output as the molten iron temperature. Here, pixels whose pixel brightness ratio standard deviation exceeds the +3σ interval were not extracted, as many of these pixels correspond to pixels with so-called overexposed highlights.

[0042] Here, "+2σ" is a value that is +2 times σ when the standard deviation of the variation in the luminance ratio for each pixel of the image is σ. Also, "+3σ" is a value that is +3 times σ when the standard deviation of the variation in the luminance ratio for each pixel of the image is σ. Furthermore, "+2σ" and "+3σ" indicate the degree of variation in the luminance ratio.

[0043] FIG. 9 is a diagram showing various temperatures analyzed by image processing of the image of the molten iron 3 taken by the two-color thermometer 21.

[0044] In the example shown in Fig. 9, the temperature measured by the two-color pyrometer 21 is lower than the temperature measured by the thermocouple 31, and the variance is large. Furthermore, while the temperature measured by the thermocouple 31 is approximately 1480°C, the 30-section moving average of the temperature measured by the two-color pyrometer 21 is 1200°C to 1300°C. The average temperature measured (molten iron temperature) in the +2σ to +3σ section using the pixel-by-pixel brightness ratio standard deviation filter is lower than the temperature measured by the thermocouple 31, but higher than the temperature measured by the two-color pyrometer 21, and the variance is small. Furthermore, the 30-section moving average of the average temperature measured (molten iron temperature) in the +2σ to +3σ section using the pixel-by-pixel brightness ratio standard deviation filter is approximately 1400°C.

[0045] In the method for continuously measuring the temperature of blast furnace molten pig iron according to the third embodiment, the brightness ratio of each pixel in an image of the molten pig iron 3 captured by the two-color thermometer 21 is analyzed using a pixel brightness ratio standard deviation filter, and pixels in the +2σ to +3σ interval of the standard deviation of the pixel brightness ratio are extracted. Then, an average temperature value obtained by averaging the temperature values ​​corresponding to the brightness ratios of each extracted pixel is adopted as the temperature of the molten pig iron. As a result, in the method for continuously measuring the temperature of blast furnace molten pig iron according to the third embodiment, the temperature value measured using the two-color thermometer 21 approaches the true value (the temperature value measured using the thermocouple 31), and the accuracy of continuous measurement of the temperature of the molten pig iron using the two-color thermometer 21 can be improved.

[0046] Furthermore, in the method for continuously measuring the blast furnace hot metal temperature according to the third embodiment, as in the method for continuously measuring the blast furnace hot metal temperature according to the first embodiment, the hot metal temperature measured by the two-color thermometer 21 may be corrected based on the hot metal temperature measured by the thermocouple 31. This makes it possible to further improve the accuracy of the continuous measurement of the hot metal temperature by the two-color thermometer 21.

[0047] (Embodiment 4) Hereinafter, a fourth embodiment of the method for continuously measuring the temperature of blast furnace molten pig iron and the method for operating a blast furnace according to the present invention will be described. Note that in the fourth embodiment, the same descriptions as those in the first to third embodiments will be omitted as appropriate.

[0048] In the method for continuously measuring the blast furnace hot metal temperature according to the fourth embodiment, similar to the method for measuring the blast furnace hot metal temperature according to the second embodiment, dust particles within the angle of view θ of the two-color thermometer 21 are blown away and removed by air injected from the tip of the air purge lance 50. Furthermore, in the method for continuously measuring the blast furnace hot metal temperature according to the fourth embodiment, similar to the method for measuring the blast furnace hot metal temperature according to the third embodiment, pixels that are minimally affected by dust particles are extracted and analyzed by image processing by the processing device 22, thereby calculating a value close to the true value. That is, the processing device 22 analyzes the brightness ratio of each pixel in each image using a pixel brightness ratio standard deviation filter, extracts pixels in the +2σ to +3σ interval of the standard deviation, and averages the temperature values ​​corresponding to the brightness ratios of the extracted pixels to output the average temperature value as the hot metal temperature.

[0049] FIG. 10 is a flowchart showing an example of a procedure for measuring the molten iron temperature by the method for continuously measuring the blast furnace molten iron temperature according to the fourth embodiment.

[0050] First, in step S1, an operator determines whether the location where the molten pig iron temperature is to be measured by the two-color thermometer 21 is in a dusty environment where a lot of dust is floating around. If the operator determines in step S1 that the environment is not dusty (No in step S1), the process proceeds to step S2. Next, in step S2, the two-color thermometer 21 photographs the molten pig iron 3 ejecting from the taphole 2, and then the process proceeds to step S3. Next, in step S3, the processing device 22 calculates the molten pig iron temperature based on the image photographed by the two-color thermometer 21, and then the process proceeds to step S4. Next, in step S4, the molten pig iron temperature calculated by the processing device 22 is output to, for example, a monitor or the like, which is a display device provided in the processing device 22.

[0051] On the other hand, if the operator determines in step S1 that the environment is dusty (Yes in step S1), the process proceeds to step S5. Next, in step S5, the air purge lance 50 is used to perform air purging toward the angle of view θ of the two-color thermometer 21, and then the process proceeds to step S6. In step S6, the operator determines whether or not the influence of dust has been eliminated when measuring the molten pig iron temperature with the two-color thermometer 21 by purging air within the angle of view θ of the two-color thermometer 21. If the operator determines in step S6 that the influence of dust has been eliminated (Yes in step S6), the process proceeds to step S2, and the processes of steps S2, S3, and S4 are performed using the two-color thermometer 21, the processing device 22, etc., in the same manner as described above.

[0052] Furthermore, if the operator determines in step S6 that the influence of dust has not been eliminated (No in step S6), the process proceeds to step S7. Next, in step S7, the two-color thermometer 21 photographs the molten iron 3 being discharged from the taphole 2, and then the process proceeds to step S8. Next, in step S8, the processing device 22 applies a pixel-by-pixel brightness ratio standard deviation filter to the image photographed by the two-color thermometer 21 to analyze the brightness ratio for each pixel and extracts pixels in the +2σ to +3σ interval of the standard deviation, and then the process proceeds to step S9. Next, in step S9, the processing device 22 calculates an average temperature value by averaging the temperature values ​​corresponding to the brightness ratio for each pixel in the extracted +2σ to +3σ interval, and then the process proceeds to step S10. Next, in step S10, the average temperature value calculated by the processing device 22 is output as the molten iron temperature to, for example, a monitor, which is a display device provided in the processing device 22.

[0053] In the method for continuously measuring the temperature of blast furnace molten pig iron according to the fourth embodiment, the influence of dust can be reduced, and the accuracy of continuous measurement of the temperature of molten pig iron by the two-color thermometer 21 can be improved.

[0054] Furthermore, in the method for continuously measuring the blast furnace hot metal temperature according to the fourth embodiment, as in the method for continuously measuring the blast furnace hot metal temperature according to the first embodiment, the hot metal temperature measured by the two-color thermometer 21 may be corrected based on the hot metal temperature measured by the thermocouple 31. This makes it possible to further improve the accuracy of the continuous measurement of the hot metal temperature by the two-color thermometer 21. [Explanation of symbols]

[0055] 1 blast furnace 2 Taphole 3. Molten iron 4. Molten slag 5 Skimmer Damper 6. Slag splash section 7. Rising section 8 Molten metal trough 9 Slag trough 10 Blast furnace main gutter 20 Work Platform 20a opening 20b opening 30 Gutter Cover 30a opening 21 Two color thermometer 22 Processing equipment 31 Thermocouple 32 Calculation Device 40 Dust collection duct 40a opening 41 Dust collection duct 41a opening 50 Air purge lance

Claims

1. A method for continuously measuring the temperature of molten iron in a blast furnace, in which the temperature of molten iron discharged from a taphole of the blast furnace is continuously measured using a radiation thermometer, comprising: measuring the temperature of the molten iron with the radiation thermometer so as to reduce the influence of dust on the temperature of the molten iron measured by the radiation thermometer; A method for continuous measurement of blast furnace molten iron temperature.

2. In the blast furnace main runner, which serves as a flow path for the molten iron and molten slag discharged from the taphole, a skimmer damper is disposed in the flow path through which the molten iron and the molten slag flow downward, and a molten iron runner into which the molten iron separated by the skimmer damper overflows from a rising portion and flows, and a slag runner into which the molten slag separated by the skimmer damper overflows from a slag splash portion and flows, are provided side by side; A dust collector for collecting dust is disposed near the skimmer damper, The temperature of the molten iron overflowing from the rising portion and flowing into the molten iron runner is measured by the radiation thermometer at a location downstream of the skimmer damper in the flow path of the blast furnace main runner. The method for continuously measuring the temperature of blast furnace molten iron according to claim 1.

3. When measuring the temperature of the molten iron discharged from the taphole with the radiation thermometer, air is purged toward a viewing angle of the radiation thermometer. The method for continuously measuring the temperature of blast furnace molten iron according to claim 1.

4. A two-color thermometer is used as the radiation thermometer, and a processing device is used to analyze the brightness ratio for each pixel of the image of the molten iron captured by the two-color thermometer, extracting pixels in the +2σ to +3σ interval of the standard deviation of the brightness ratio for each pixel, and averaging the temperature values ​​corresponding to the brightness ratio for each extracted pixel to determine the average temperature value as the molten iron temperature. The method for continuously measuring the temperature of blast furnace molten iron according to claim 1.

5. the measured value of the molten pig iron measured by the radiation thermometer is corrected by the measured value of the molten pig iron measured by the thermocouple; The method for continuously measuring the temperature of blast furnace molten iron according to any one of claims 1 to 4.

6. The method for continuously measuring the temperature of blast furnace molten iron according to any one of claims 1 to 4 is used to continuously measure the temperature of molten iron discharged from a taphole of a blast furnace. How to operate a blast furnace.

7. The method for continuously measuring the temperature of molten iron in a blast furnace according to claim 5 is used to continuously measure the temperature of molten iron discharged from a taphole of a blast furnace. How to operate a blast furnace.

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