Gas flow velocity distribution calculation device, gas flow velocity calculation method, and operation method for blast furnace

Abstract

To provide a gas flow velocity distribution calculation device, a gas flow velocity calculation method, and an operation method for a blast furnace, capable of accurately determining a gas flow velocity distribution just above a charging surface of a raw material charged into the blast furnace.SOLUTION: A device for calculating gas flow velocity distribution of a blast furnace includes: a temperature measurement unit 10 for measuring the gas temperature distribution just above a charging surface of a raw material intermittently charged into the blast furnace; a height measurement unit 11 for measuring a charging height of the raw material on the charging surface; and a calculation unit 13 for calculating the gas flow velocity distribution just above the charging surface of the raw material on the basis of the gas temperature distribution and the charging height.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a gas flow velocity distribution calculation device, a gas flow velocity calculation method, and an operation method for a blast furnace. [Background technology]

[0002] In blast furnace operation, the major objectives are to operate at a low reducing agent rate and a high productivity rate, with the premise of trouble-free stable operation. In order to achieve these objectives, there is a challenge in optimizing the distribution of the materials charged from the top in the circumferential and radial directions.

[0003] In blast furnace operation, raw materials such as iron ore and coke are charged from the top of the blast furnace, and are heated and reduced by high-temperature gas blown in from the tuyere installed in the lower part of the blast furnace. If the distribution of raw materials near the top of the furnace after charging (charge distribution) is not appropriate, the appropriate heating and reduction of the descending raw materials is hindered, making it difficult to maintain operation at a low reducing agent ratio. In addition, if the charge distribution is not appropriate, the risk of problems such as furnace heat reduction and blow-through increases. Furthermore, if the charge distribution is not appropriate, the peripheral flow, which is the blast furnace gas flow near the furnace wall, becomes too large, and heat loss also increases. For this reason, by optimizing the gas flow velocity distribution in the blast furnace, the heating and reduction of the charged raw materials can be performed appropriately, and the occurrence of problems such as reduced heat loss from the furnace wall and blow-through can be suppressed. In addition, by optimizing the gas flow velocity distribution in the blast furnace, the coke usage ratio can be reduced, and operating costs can be reduced.

[0004] Understanding the distribution state of the gas flow rate at the charging surface of the blast furnace raw materials is important as a criterion for determining whether the distribution state of the charged raw materials and the temperature rise are performed appropriately. However, the inside of a blast furnace is a bad environment, with a lot of dust and the temperature sometimes reaching 500 ° C or higher due to blow-through. For this reason, at present, it is difficult to measure the gas flow rate distribution in the blast furnace using a sensor such as that shown in Patent Document 1 online at all times, and it is also difficult to measure it temporarily. On the other hand, Patent Document 2 proposes a method for measuring the gas flow distribution in the furnace based on the gas temperature and raw material height measured at multiple measurement points and the total gas flow rate of the furnace gas, as a method for estimating the gas flow rate distribution in the blast furnace. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2013-11582 A [Patent Document 2] JP 2010-209404 A Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, the method of Patent Document 2 is premised on the use of values ​​measured by a throat probe installed protruding from the outer periphery of the throat of the blast furnace, and temperature is measured by several thermocouples installed in the radial direction of the throat probe. However, if more points are measured, the throat probe will interfere with the charging of raw materials, making it impossible to charge them properly. For this reason, in the method of Patent Document 2, the temperature is measured in the radial direction from at most four directions, and since the number of measurement points is small, the temperature measurement value is interpolated to estimate the temperature in the unmeasured area. However, with such a method, it is difficult to measure local changes in flow velocity, and there is a problem that the measurement accuracy is low due to the large number of areas where the temperature is not measured.

[0007] Therefore, the present invention has been made with a focus on the above problems, and aims to provide a blast furnace gas flow velocity distribution calculation device, a gas flow velocity calculation method, and an operation method that can accurately determine the gas flow velocity distribution directly above the charging surface of the raw materials charged into the blast furnace. [Means for solving the problem]

[0008] (1) According to one aspect of the present invention, there is provided a gas flow velocity distribution calculation device for a blast furnace, comprising: a temperature measurement unit that measures a gas temperature distribution directly above a charging surface of raw materials intermittently charged into a blast furnace; a height measurement unit that measures the charging height of the raw materials at the charging surface; and a calculation unit that calculates a gas flow velocity distribution directly above the charging surface of the raw materials based on the gas temperature distribution and the charging height.

[0009] (2) In the blast furnace gas flow velocity distribution calculation device described above in (1), the temperature measurement unit and the height measurement unit do not use a furnace mouth probe.

[0010] (3) In the blast furnace gas flow velocity distribution calculation device of (1) or (2) above, the temperature measurement unit is an ultrasonic thermometer, and the height measurement unit is a scanning type distance meter using microwaves or millimeter waves.

[0011] (4) In the gas flow velocity distribution calculation device for a blast furnace according to any one of (1) to (3), the calculation unit calculates the gas flow velocity at each part of the charging surface of the raw material based on the time series data of the gas temperature at each part of the charging surface, the extrapolated value of the gas temperature at each part of the charging surface, and the charging thickness calculated from the change in the charging height at each part of the charging surface, and uses, as the extrapolated value, a temperature rise curve obtained by fitting an increasing function with a linear time constant to the temperature rise data during past charging of the raw material at each part of the charging surface.

[0012] (5) According to one aspect of the present invention, there is provided a method for calculating a gas flow velocity distribution in a blast furnace, comprising measuring a gas temperature distribution directly above a charging surface of raw materials intermittently charged into a blast furnace, measuring a charging height of the raw materials at the charging surface, and calculating a gas flow velocity distribution directly above the charging surface of the raw materials based on the gas temperature distribution and the charging height.

[0013] (6) In the method for calculating the gas flow velocity distribution of a blast furnace described above in (5), a furnace throat probe is not used when measuring the gas temperature distribution and when measuring the charging height.

[0014] (7) In the method for calculating the gas flow velocity distribution of a blast furnace according to (5) or (6) above, an ultrasonic thermometer is used to measure the gas temperature distribution, and a scanning range finder using microwaves or millimeter waves is used to measure the charging height.

[0015] (8) In the blast furnace gas flow velocity distribution calculation device of any one of (5) to (7) above, when calculating the gas flow velocity distribution, the gas flow velocity of each part of the charging surface of the raw material is calculated based on the time series data of the gas temperature of each part of the charging surface, the extrapolated value of the gas temperature of each part of the charging surface, and the charging thickness calculated from the change in the charging height of each part of the charging surface, and a temperature rise curve in which an increasing function with a time constant of a linear value is fitted to the temperature rise data during past charging of the raw material at each part of the charging surface is used as the extrapolated value.

[0016] (9) According to one aspect of the present invention, there is provided a method for operating a blast furnace, comprising: calculating a gas flow velocity distribution immediately above a charging surface of raw materials charged into the blast furnace using the gas flow velocity distribution calculation method for the blast furnace according to any one of (5) to (8) above during operation of the blast furnace. Effect of the Invention

[0017] According to one aspect of the present invention, a gas flow velocity distribution calculation device, a gas flow velocity calculation method, and an operation method for a blast furnace are provided, which can accurately determine the gas flow velocity distribution directly above the charging surface of the raw material charged into the blast furnace. [Brief description of the drawings]

[0018] [Figure 1] 1 is a configuration diagram showing an example of the configuration of a gas flow velocity distribution calculation device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram showing an example of installation of some devices of a gas flow velocity distribution calculation device. [Diagram 3] 1 is a graph showing an example of temperature transitions of the gas directly above the raw material and the raw material being charged at a specified position on the raw material charging surface. [Figure 4] 4 is a graph showing an example of fitting in the first embodiment. [Diagram 5] FIG. 11 is an explanatory diagram showing temperature measurement points of an ultrasonic thermometer in Example 2. [Figure 6] 13 is a graph showing the measurement results of gas flow velocity distribution in Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] In the following detailed description, an embodiment of the present invention will be described with reference to the drawings. In the description of the drawings, identical or similar parts are given identical or similar symbols, and duplicated explanations are omitted. Each drawing is schematic and may differ from the actual one. In addition, the embodiments shown below are examples of devices and methods for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention does not specify the materials, structures, arrangements, etc. of the components as described below. The technical idea of ​​the present invention can be modified in various ways within the technical scope defined by the claims described in the claims.

[0020] <Device configuration> The configuration of an apparatus according to one embodiment of the present invention will be described with reference to Figures 1 and 2. A gas flow velocity distribution calculation apparatus 1 for a blast furnace 2 according to this embodiment is an apparatus for calculating a gas flow velocity distribution immediately above the charging surface of raw materials 3 charged into the blast furnace 2, and includes a temperature measurement unit 10, a height measurement unit 11, a storage unit 12, a calculation unit 13, and a display unit 14. The gas flow velocity distribution calculation apparatus 1 has a sondeless configuration that does not use a furnace throat sonde.

[0021] The temperature measuring unit 10 measures the gas temperature distribution directly above the charging surface of the raw materials 3 charged into the blast furnace 2. The temperature measuring unit 10 is preferably a temperature sensor capable of measuring the gas temperature distribution directly above the charging surface of the raw materials 3 in a probeless manner within one minute at the latest. The temperature measuring unit 10 is preferably an ultrasonic thermometer (sonic temperature sensor). In this case, the temperature measuring unit 10 is composed of a plurality of ultrasonic temperature sensors provided on the outer periphery of the throat 20 of the blast furnace 2. As the temperature measuring unit 10, for example, a blast furnace top gas temperature measuring system "SOMA" by TMT of Germany, which is capable of determining the temperature distribution based on the sound speed difference, can be used. The measurement of the gas temperature distribution by the temperature measuring unit 10 is performed continuously during the operation of the blast furnace 2. The measurement period (sampling period) of the gas temperature distribution is not particularly limited, but is preferably set to a period at least to the extent that the change in the gas temperature immediately after the charging of the raw materials 3 can be known. For example, the measurement period of the gas temperature distribution may be 1 min. In the sonic temperature measuring unit 10, by increasing the number of sound transmitters and receivers installed around the periphery of the throat 20 of the blast furnace 2, it is possible to increase the number of temperature points calculated from a predetermined equation based on the relationship between the sonic speed and the gas temperature using the measured sonic speed. Furthermore, it is possible to obtain the overall temperature of the upper part of the charging surface of the raw materials 3 by interpolating the calculated temperature measuring point values. That is, in this embodiment, the temperature of the charging surface of the raw materials 3 is obtained by measurement by the temperature measuring unit 10. Note that the measurement by the temperature measuring unit 10 may include estimation of the temperature of the calculated temperature measuring points described above in addition to measurement of the temperature of the temperature points using a sonic thermometer or the like.

[0022] The height measuring unit 11 measures the charging height of the raw materials 3 charged into the blast furnace 2 on the charging surface. The charging height is the vertical height position of the charging surface. The height measuring unit 11 is preferably capable of measuring the charging height of the entire charging surface of the raw materials 3 without a probe, and is more preferably a scanning type distance meter using microwaves or millimeter waves. For example, in the example shown in FIG. 2, the height measuring unit 11 is a scanning type distance meter provided on the upper part of the furnace throat 20. In addition, for example, the height measuring unit 11 can be a "lanceless blast furnace 3D profile meter milliscanner" manufactured by WADECO. The measurement of the charging height by the height measuring unit 11 is performed for each batch at each timing when the raw materials 3 are charged into the blast furnace 2 during the operation of the blast furnace 2.

[0023] The memory unit 12 is a storage device that acquires and stores the gas temperature distribution measured by the temperature measurement unit 10 and the charging height measured by the height measurement unit 11. The memory unit 12 also acquires the total gas flow rate, which is the gas flow rate discharged from the throat 20 of the blast furnace 2, from a host computer or the like and stores it. The total gas flow rate is continuously measured by a measurement device provided at the throat 20 or ahead of the throat 20 during operation of the blast furnace 2. The memory unit 12 stores the gas temperature distribution, the charging height, and the total gas flow rate as time-series data. The gas temperature distribution stored in the memory unit 12 may also be data that has been subjected to time-averaging. In this case, the time-averaging of the gas temperature distribution is performed by a calculation means or the temperature measurement unit 10 (not shown). Furthermore, the charging height stored in the memory unit 12 may be the charging thickness for each batch. The charging depth is the difference between the charging height after the raw materials 3 are charged next time and the previous charging height, and is calculated on the charging surface by a calculation means (not shown) or a height measuring unit 11. Furthermore, the memory unit 12 also acquires and stores the gas flow velocity distribution calculated by the calculation unit 13.

[0024] The calculation unit 13 is a calculation device that calculates the gas flow velocity distribution immediately above the charging surface of the raw materials 3 based on the gas temperature distribution and the charging height. The calculation unit 13 acquires the gas temperature distribution, the charging height, and the total gas flow rate from the memory unit 12, and calculates the gas flow velocity distribution immediately above the charging surface of the raw materials 3 using these data. The details of the calculation method of the gas flow velocity distribution by the calculation unit 13 will be described later. The calculated gas flow velocity distribution is sent to the memory unit 12 and the display unit 14.

[0025] The display unit 14 is a display device that displays the gas flow velocity distribution calculated by the calculation unit 13.

[0026] <Calculation method for gas flow velocity distribution> An example of a method for calculating the gas flow velocity distribution is shown below. The method for calculating the gas flow velocity distribution may be the same as the method described in Patent Document 2.

[0027] First, to explain the principle, a phenomenon occurring during the operation process of a blast furnace 2 will be described. In an operating blast furnace 2, raw materials 3 such as iron ore and coke are intermittently charged into the furnace from the top of the blast furnace 2 through a rotating chute (not shown) or the like. In the blast furnace 2, high-temperature air blown in from a tuyere 21 installed at the bottom of the furnace reacts with coke and the like to become reducing furnace gas, which flows into the top of the furnace through gaps between the charged materials and is discharged from the top of the furnace to the outside of the blast furnace body. In this process, the high-temperature furnace gas exchanges heat between the raw materials 3, which are at room temperature or slightly higher than room temperature, and the raw materials 3, which are at a lower temperature. For this reason, immediately after the raw materials 3 are charged into the blast furnace, the temperatures of the furnace gas flowing through the top of the furnace and the charged raw materials 3 change (down and up) due to the effect of heat exchange.

[0028] The method for calculating the gas flow velocity distribution according to this embodiment is a technique based on a countercurrent heat transfer model capable of expressing the above-mentioned heat exchange, and calculates the gas flow velocity distribution from the temperature change before and after the charging of the raw material 3 at the timing of charging the raw material and the raw material charging speed (charging thickness) of one batch.

[0029] Fig. 3 shows an example of temperature transition of the gas directly above the raw material 3 and the charged raw material 3 at a predetermined position on the charging surface of the raw material 3. Fig. 3 shows the gas temperature rise after the previous raw material charging, the gas temperature drop due to the subsequent raw material charging, and the subsequent temperature rise. The calculation method of the gas flow velocity distribution estimation method of this embodiment will be described using this Fig. 3.

[0030] In Figure 3, ΔT g is the difference between the bottom gas temperature and the top gas temperature. The bottom gas temperature is calculated by extrapolation using the temperature of the previously charged raw materials 3. Details of the method for estimating the bottom gas temperature will be described later. The bottom gas temperature is the temperature rise after the raw materials 3 are charged, which corresponds to the raw material thickness used in the calculation.

[0031] Based on the concept of countercurrent heat transfer, if the gas flow rate does not change during Δt, the following equations (1) and (2) hold at times t1 and t2, respectively. V g ×C g ×ΔT g1 = h×a×(T g1 -T s1 ) × S × ΔZ (1) V g ×C g ×ΔT g2 = h×a×(T g2 -T s2 ) × S × ΔZ (2) Where: V g : Furnace gas flow rate [kg / h] C g : Gas specific heat [kcal / kg℃] T g1 : Gas temperature at time t1 [℃] T g2 : Gas temperature at time t2 [℃] T s1 : Temperature of the raw material charged this time at time t1 [℃] T s2 : Temperature of the raw material charged this time at time t2 [℃] h: Heat transfer coefficient [kcal / m 2 h℃] a: Particle surface area per unit volume [m 2 / m 3 ] S: Cross-sectional area of ​​the furnace top [m 2 ] ΔZ: Charging depth of the raw material charged this time [m]

[0032] From equations (1) and (2), if we set K = h × a × S, we obtain the following equation (3). ΔT s = T s2 -T s1 = (T g2 -T g1 )-V g ×C g ×(ΔT g2 -ΔT g1 ) / (K×ΔZ) (3) Where: ΔT s : Temperature rise of charged raw materials at Δt [℃]

[0033] On the other hand, the amount of heat exchanged between the gas and the solid in countercurrent flow during Δt is equal, so the following equation (4) holds true. C g ×ΔT g ×V g × Δt = C s ×ΔT s ×V s ×Δt (4) Where: C s : Solid specific heat [kcal / kg℃]

[0034] Furthermore, if Δt is one sampling, equation (4) can be approximated by the following equation (5). (ΔT g1 +ΔT g2 )×V g / 2= ΔT s ×V s / twenty five) Where: V s : Charge flow rate [kg / h] (layer thickness per batch)

[0035] In the example shown in FIG. 3, the raw material 3 is charged in a time period equivalent to the temperature data sampling period (1 min). In addition, assuming that the time difference between t1 and t2 is small, ΔZ=V s Then, from equations (3) and (5), we obtain equation (6). (T g2 -T g1 )-V g ×C g ×(ΔT g2 -ΔT g1 ) / (K×ΔZ)= (ΔT g1 +ΔT g2 )×V g / ΔZ (6)

[0036] Therefore, the flow velocity [m / h] in the vicinity of the temperature is expressed by the following equation (7). V g =(T g2 -T g1 )×ΔZ / 〔C g ×(ΔT g2 -ΔT g1 ) / K+(ΔT g1 +ΔT g2 ) (7)

[0037] For the unknown variable K in equation (7), the flow velocity [m / h] is calculated for all thermometer values, and then the cross-sectional area at the stock level height is divided around the temperature measurement point, and the flow rate [m 3 / h]. Then, use goal-seek calculations to find K so that the total of these amounts matches the total gas flow rate at the furnace port.

[0038] By carrying out the above calculations, the gas flow velocity at a predetermined position on the charging surface of the raw materials 3 can be calculated. In this embodiment, the gas flow velocity distribution on the entire charging surface is calculated by calculating the gas flow velocity at each part of the charging surface of the raw materials 3. The position for calculating the gas flow velocity is preferably the height position measured by the temperature measuring unit 10. In other words, when an ultrasonic temperature sensor is used for the temperature measuring unit 10, it is preferable to set the height at which the ultrasonic temperature sensor is installed. In addition, when the height measuring unit 11 is a scanning type distance meter using microwaves or millimeter waves, the raw material surface can be measured with an accuracy of about ±50 mm, and the charging thickness of the raw materials at the charging surface can be measured in consideration of the accuracy of raw material charging from above.

[0039] (Method of estimating bottom gas temperature) A method for estimating the bottom surface gas temperature used to calculate the gas flow rate will be described. In this embodiment, the bottom surface gas temperature is obtained from a temperature rise curve after the raw material is charged. The temperature rise curve is obtained using temperature rise data, which is time-series data of the gas temperature distribution during the past charging of the raw material 3. In addition, the temperature rise curve is obtained from temperature changes (temperature rise process after the raw material is charged) in at least two past cycles.

[0040] If data processing such as moving average or filter is simply applied to the time series data of the furnace throat temperature obtained by the sonic thermometer, it may be affected by noise-like fluctuations between batches (between the charging of raw materials 3), and may differ from the phenomenon that is actually being captured. Considering the physical characteristics of the raw material charging described above, it is considered appropriate that the extrapolation function is an upwardly convex linear increasing function that converges to a constant value at an infinite time. For this reason, the temperature rise curve is obtained by extracting the data between min and max of the temperature during charging and fitting the temperature value during that time with a linear increasing function with a time constant. The temperature rise curve can be obtained, for example, using the following formula (8). Here, the gain G and the time constant T are adjusted to fit so that the error is minimized.

[0041]

number

[0042] When using an ultrasonic temperature system as in this embodiment, the response speed is faster than that of a thermocouple of a furnace throat probe used conventionally, so that it detects minute temperature fluctuations. Furthermore, during the charging process between charging batches, the raw material 3 flows in during charging, and the airflow resistance increases at the point where the raw material 3 is charged, and decreases at the point where the raw material 3 is not charged. In addition, since the raw material 3 is charged while rotating, the flow distribution and gas temperature may change slightly even during the charging process (midway). Due to these factors, it is considered that the temperature does not increase uniquely between charging, but fluctuates up and down. The measurement by the height measuring unit 11 during charging can accurately obtain data before and after the batch when no raw material is charged. Therefore, it is important to obtain a representative uniquely increasing temperature change between batches (start to end of raw material charging) required for flow rate calculation in order to improve the estimation accuracy of the gas flux distribution. And, this is possible by fitting to the above function. In this embodiment, the gas temperature distribution directly above the raw material charging surface and the raw material charging height are measured. Since there are no obstacles on the raw material charging surface, any region can be measured, but it is preferable that the entire charging surface be measured.

[0043] <Modification> Although the present invention has been described above with reference to specific embodiments, it is not intended that the invention be limited by these descriptions. By referring to the description of the present invention, other embodiments of the present invention including various modifications in addition to the disclosed embodiments will be apparent to those skilled in the art. Therefore, it should be understood that the embodiments of the invention described in the claims also include embodiments including these modifications described herein, either alone or in combination.

[0044] For example, in the above embodiment, when calculating the gas flow velocity distribution, the flow velocity at each part of the charging surface is calculated, but the present invention is not limited to such an example. In the operation of the blast furnace 2, it is desired to make the gas flow velocity distribution in the circumferential direction (at the same radial position) as uniform as possible, so that the state can also be judged from the gas flow velocity balance in the circumferential direction. For this reason, it is also possible to calculate only the relative balance of the gas flow velocity at the charging surface. In this case, it is not necessary to apportion the total gas flow rate of the furnace throat 20 in the above embodiment, and it is also not necessary to use the total gas flow rate of the furnace throat 20.

[0045] Furthermore, the present invention can also be applied to a method for operating a blast furnace 2. In the method for operating a blast furnace 2 according to the present invention, the gas velocity distribution immediately above the charging surface of the raw materials 3 charged into the blast furnace 2 is calculated using the gas velocity distribution calculation method for the blast furnace 2 of the above embodiment and modified example during operation of the blast furnace 2. In such an operation method, the distribution control of the raw material charging can be improved according to the calculated gas velocity distribution, and therefore the coke usage rate can be reduced.

[0046] <Effects of the embodiment> (1) According to one embodiment of the present invention, a gas flow velocity distribution calculation device 1 for a blast furnace 2 includes a temperature measurement unit 10 that measures a gas temperature distribution directly above a charging surface of raw materials 3 that are intermittently charged into the blast furnace 2, a height measurement unit 11 that measures the charging height of the raw materials 3 at the charging surface, and a calculation unit 13 that calculates the gas flow velocity distribution directly above the charging surface of the raw materials 3 based on the gas temperature distribution and the charging height.

[0047] According to the above configuration (1), by calculating the gas flow velocity distribution at the charging surface of the raw material 3, it is possible to measure local changes in flow velocity.

[0048] (2) In the gas flow velocity distribution calculation device 1 for the blast furnace 2 described above in (1), the temperature measurement unit 10 and the height measurement unit 11 do not use a furnace throat probe.

[0049] Here, in the method using a throat probe as in Patent Document 2, it is possible to measure the temperature at multiple points by increasing the number of throat probes (the number of arms). However, because of interference with the measurement of the profile meter that measures the thickness of the raw material being charged, accurate measurement by the profile meter at the charging surface is hindered. Similarly, in order to measure the thickness of the raw material being charged at many points using a profile meter with a throat probe, it is possible to consider a means of charging the throat probe with a profile meter from multiple directions and measuring it. However, in this case, because of interference with the measurement of the raw material charging and the throat gas temperature, the study in Patent Document 2 only measured at one radial point, making it difficult to accurately calculate the entire flow velocity distribution. On the other hand, according to the above configuration (2), since no arm is installed directly above the raw material charging surface such as the throat probe, the gas flow velocity distribution at the charging surface can be measured without interfering with other operations such as raw material charging. In addition, interference between the temperature measuring unit 10 and the height measuring unit 11 can also be prevented.

[0050] (3) In the gas flow velocity distribution calculation device 1 for the blast furnace 2 described above in (1) or (2), the temperature measurement unit 10 is an ultrasonic thermometer, and the height measurement unit 11 is a scanning type distance meter using microwaves or millimeter waves.

[0051] According to the above configuration (3), it is possible to measure changes in the furnace throat in a short time compared to the method of Patent Document 2, which is based on a thermocouple with a slow temperature response, and therefore it is possible to measure the gas flow velocity distribution inside the furnace with higher accuracy.

[0052] (4) In the gas flow velocity distribution calculation device 1 for the blast furnace 2 of any one of (1) to (3) above, the calculation unit 13 calculates the gas flow velocity at each part of the charging surface of the raw materials 3 based on the time series data of the gas temperature at each part of the charging surface, the extrapolated value of the gas temperature at each part of the charging surface, and the charging thickness calculated from the change in the charging height at each part of the charging surface, and uses, as the extrapolated value, a temperature rise curve in which an increasing function with a linear time constant is fitted to the temperature rise data during past raw material charging at each part of the charging surface.

[0053] According to the above configuration (4), a highly accurate value can be estimated as an extrapolated value, so that the in-furnace gas flow velocity distribution can be measured with higher accuracy.

[0054] (5) A method for calculating a gas flow velocity distribution in a blast furnace according to one embodiment of the present invention measures the gas temperature distribution directly above the charging surface of raw materials intermittently charged into the blast furnace 2, measures the charging height of the raw materials at the charging surface, and calculates the gas flow velocity distribution directly above the charging surface of the raw materials based on the gas temperature distribution and the charging height.

[0055] (6) In the method for calculating the gas flow velocity distribution of a blast furnace described above in (5), a furnace throat probe is not used when measuring the gas temperature distribution and the charging height.

[0056] (7) In the method for calculating the gas flow velocity distribution of a blast furnace according to (5) or (6) above, an ultrasonic thermometer is used to measure the gas temperature distribution, and a scanning range finder using microwaves or millimeter waves is used to measure the charging height.

[0057] (8) In the method for calculating the gas flow velocity distribution of a blast furnace according to any one of the above (5) to (7), when calculating the gas flow velocity distribution, the gas flow velocity at each part of the charging surface of the raw material is calculated based on the time series data of the gas temperature at each part of the charging surface, the extrapolated value of the gas temperature at each part of the charging surface, and the charging thickness calculated from the change in the charging height at each part of the charging surface, and a temperature rise curve in which an increasing function with a linear time constant is fitted to the temperature rise data during past charging of raw materials at each part of the charging surface is used as the extrapolated value.

[0058] According to the above configurations (5) to (8), the same effects as those of the above configurations (1) to (4) can be obtained.

[0059] (9) According to one embodiment of the present invention, there is provided a method for operating a blast furnace, which, during operation of a blast furnace 2, calculates a gas flow velocity distribution immediately above a charging surface of raw materials charged into the blast furnace using the method for calculating a gas flow velocity distribution of a blast furnace according to any one of (5) to (8) above. EXAMPLES

[0060] Example 1 carried out by the present inventors will be described. In Example 1, a temperature rise curve was obtained by applying and fitting equation (8) to one temperature point measured by an ultrasonic thermometer, which is the temperature measuring unit 10. The temperature data used was data between batches, and data was extracted from after the raw material was charged until just before the next charge. Although this data is data between batches, it was confirmed that the data itself does not increase uniquely, but decreases midway and then increases. If the average temperature rise for all input raw materials between batches is known, the purpose of the calculation can be met. The results of the example are shown in FIG. 4. As shown in FIG. 4, it was confirmed that by using this function, it is possible to obtain an appropriate temperature value without being affected by noise-like fluctuations when calculating the temperature, especially when calculating the extrapolated temperature. EXAMPLES

[0061] In Example 2, the same calculation as in Example 1 was applied to each temperature measurement point of the sonic thermometer, the gas flow velocity of each measurement point was calculated, and the total gas flow velocity flow rate value was apportioned according to the ratio of the gas flow velocity value of each measurement point obtained, to obtain the gas flow velocity distribution. The measurement points are a total of 57 points (circles indicate measurement points, 7 points in the radial direction × 8 points in the circumferential direction + 1 point at the center) as shown in Figure 5.

[0062] The calculation results of the gas flow rate distribution in Example 2 are shown in FIG. 6. In FIG. 6, values ​​for display are calculated by interpolation calculation except for the temperature measurement points. This result is consistent with the assumed so-called W-shaped flow rate distribution, and it was confirmed that the balance in the circumferential direction is slightly different. From the above results, it was confirmed that the gas flow rate can be measured with high accuracy according to the blast furnace gas flow rate distribution measuring device and the gas flow rate distribution measuring method according to the above embodiment. In addition, by using an ultrasonic thermometer, it is possible to measure the temperature at even more measurement points (for example, measurement points shifted in the radial or circumferential direction from the measurement points in FIG. 5), so that the gas flow rate can be measured with higher accuracy. [Explanation of symbols]

[0063] 1. Gas flow velocity distribution calculation device 10 Temperature measurement section 11 Height measurement section 12 Storage section 13 Calculation section 14 Display section 2 blast furnace 20 Hearth 21 Tuyere 3 Raw materials

Claims

1. A temperature measuring unit that measures a gas temperature distribution immediately above a charging surface of the raw materials intermittently charged into the blast furnace; A height measuring unit that measures the charging height of the raw material at the charging surface; a calculation unit that calculates a gas flow velocity distribution directly above the charging surface of the raw material based on the gas temperature distribution and the charging height; A blast furnace gas flow velocity distribution calculation device comprising:

2. The gas flow velocity distribution calculation device for a blast furnace according to claim 1 , wherein the temperature measurement unit and the height measurement unit do not use a furnace throat probe.

3. The temperature measuring unit is an ultrasonic thermometer, The gas flow velocity distribution calculation device for a blast furnace according to claim 2 , wherein the height measurement unit is a scanning type distance meter using microwaves or millimeter waves.

4. The calculation unit is Calculate the gas flow velocity at each part of the charging surface of the raw material based on the time series data of the gas temperature at each part of the charging surface, the extrapolated value of the gas temperature at each part of the charging surface, and the charging thickness calculated from the change in the charging height at each part of the charging surface; The blast furnace gas flow velocity distribution calculation device according to any one of claims 1 to 3, wherein a temperature rise curve in which a time constant is fitted to a linear increasing function for past temperature rise data between the charging of the raw materials at each part of the charging surface is used as the extrapolated value.

5. Measure the gas temperature distribution directly above the charging surface of the raw materials intermittently charged into the blast furnace, The charging height of the raw material is measured at the charging surface, A method for calculating a gas flow velocity distribution in a blast furnace, the method comprising: calculating a gas flow velocity distribution directly above the charging surface of the raw materials based on the gas temperature distribution and the charging height.

6. The method for calculating a gas flow velocity distribution in a blast furnace according to claim 5, wherein a furnace throat probe is not used when measuring the gas temperature distribution and when measuring the charging height.

7. When measuring the gas temperature distribution, an ultrasonic thermometer is used, The method for calculating a gas flow velocity distribution in a blast furnace according to claim 6, wherein a scanning range finder using microwaves or millimeter waves is used when measuring the charging height.

8. When calculating the gas velocity distribution, Calculate the gas flow velocity at each part of the charging surface of the raw material based on the time series data of the gas temperature at each part of the charging surface, the extrapolated value of the gas temperature at each part of the charging surface, and the charging thickness calculated from the change in the charging height at each part of the charging surface; The extrapolated value is a temperature rise curve in which a time constant is fitted to a linear increasing function for past temperature rise data between the charging of the raw materials at each part of the charging surface. The method for calculating a gas flow velocity distribution of a blast furnace according to any one of claims 5 to 7.

9. During operation of a blast furnace, a gas flow velocity distribution directly above a charging surface of raw materials charged into the blast furnace is calculated using the gas flow velocity distribution calculation method for the blast furnace according to any one of claims 5 to 7. A method for operating a blast furnace.

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