Blast furnace gas velocity distribution calculation device, gas velocity calculation method, and operation method

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 blast furnace gas velocity distribution calculation device, a gas velocity calculation method, and an operation method. [Background technology]

[0002] In blast furnace operation, the major goals are low reducing agent ratio operation and high pig production ratio operation, all based on the premise of stable operation without trouble. To achieve these, there is a challenge in optimizing the circumferential and radial distribution of the raw materials charged from above.

[0003] In blast furnace operation, raw materials such as iron ore and coke are charged into the furnace from the top and heated and reduced by high-temperature gas blown in from tuyeres located at the bottom of the furnace. If the distribution of raw materials near the top of the furnace after charging (charge distribution) is not appropriate, the proper heating and reduction of the descending raw materials will be hindered, making it difficult to maintain operation at a low reducing agent ratio. Furthermore, an improper charge distribution increases the risk of problems such as a drop in furnace temperature and blow-through. In addition, an improper charge distribution leads to excessive peripheral flow, which is the blast furnace gas flow near the furnace wall, resulting in increased heat loss. Therefore, by optimizing the gas flow velocity distribution inside the blast furnace, the heating and reduction of the charged raw materials can be properly carried out, reducing heat loss from the furnace wall and suppressing problems such as blow-through. Moreover, by optimizing the gas flow velocity distribution inside the blast furnace, the ratio of coke used can be reduced, thereby lowering operating costs.

[0004] Understanding the distribution state of gas flow velocity on the charging surface of blast furnace raw materials is important as a judgment material for whether the distribution state and temperature rise of the charged raw materials are appropriately carried out. However, the inside of the blast furnace has a lot of dust and is in a harsh environment, such as sometimes reaching a high temperature of 500 °C or more due to blowing through. Therefore, at present, measuring the gas flow velocity distribution inside the blast furnace with a sensor as shown in Patent Document 1 is difficult for continuous online measurement and also difficult for temporary measurement. On the other hand, as a method for estimating the gas flow velocity distribution inside the blast furnace, Patent Document 2 proposes a method for measuring the gas flow distribution inside the furnace based on the gas temperature, raw material height measured at multiple measurement points, and the total gas flow rate of the gas inside the furnace.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, the method of Patent Document 2 is premised on using the values measured by the tuyere sonde protruding and installed from the outer periphery of the tuyere part of the blast furnace, and temperature measurement is performed with a thermocouple at several points installed in the radial direction of the tuyere sonde. However, if more multi-point temperature measurements are to be performed, the tuyere sonde will interfere with the raw material charging and proper charging cannot be achieved. Therefore, in the method of Patent Document 2, for temperature measurement in the radial direction, at most four-direction temperature measurements are carried out, and since the number of measurement points is small, the temperature values are interpolated and estimated for the unmeasured regions. However, with such a method, it is difficult to measure local changes in flow velocity, and the problem is that the measurement accuracy is low due to many unmeasured regions.

[0007] Therefore, the present invention has been made in view of the above-mentioned problems, and aims to provide a blast furnace gas velocity distribution calculation device, a gas velocity calculation method, and an operating method that can accurately determine the gas 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, a blast furnace gas velocity distribution calculation device is provided, comprising: a temperature measuring unit for measuring the gas temperature distribution directly above the charging surface of raw materials intermittently charged into the blast furnace; a height measuring unit for measuring the charging height of the raw materials at the charging surface; and a calculation unit for calculating the gas 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 velocity distribution calculation device described in (1) above, the temperature measurement unit and the height measurement unit do not use a furnace mouth sonde.

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

[0011] (4) In the gas velocity distribution calculation device for any one of the blast furnaces described in (1) to (3) above, the calculation unit calculates the gas velocity at each part of the raw material charging surface 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. As the extrapolated value, the calculation unit uses a temperature rise curve obtained by fitting a first-order increasing function to the past temperature rise data between raw material charges at each part of the charging surface.

[0012] (5) According to one aspect of the present invention, a method for calculating the gas velocity distribution of a blast furnace is provided, which involves measuring the gas temperature distribution directly above the charging surface of raw materials intermittently charged into the blast furnace, measuring the charging height of the raw materials at the charging surface, and calculating the gas 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 velocity distribution of the blast furnace described in (5) above, a furnace mouth sonde is not used when measuring the gas temperature distribution and when measuring the charging height.

[0014] (7) In the method for calculating the gas velocity distribution of a blast furnace described in (5) or (6) above, an ultrasonic thermometer is used when measuring the gas temperature distribution, and a scanning rangefinder using microwaves or millimeter waves is used when measuring the charging height.

[0015] (8) In the gas velocity distribution calculation device for any one of the blast furnaces described in (5) to (7) above, when calculating the gas velocity distribution, the gas velocity at each part of the raw material charging surface 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. As the extrapolated value, a temperature rise curve is used at each part of the charging surface, obtained by fitting a first-order increasing function to the past temperature rise data between raw material charges.

[0016] (9) According to one aspect of the present invention, a method for operating a blast furnace is provided, which, during the operation of the blast furnace, calculates the gas velocity distribution directly above the charging surface of the raw materials charged into the blast furnace using the blast furnace gas velocity distribution calculation method described in any one of (5) to (8) above. [Effects of the Invention]

[0017] According to one aspect of the present invention, a blast furnace gas velocity distribution calculation device, a gas velocity calculation method, and an operation method are provided that can accurately determine the gas velocity distribution directly above the charging surface of the raw materials charged into the blast furnace. [Brief explanation of the drawing]

[0018] [Figure 1] This is a configuration diagram showing an example of the configuration of a gas flow velocity distribution calculation device according to one embodiment of the present invention. [Figure 2] This is a schematic diagram showing an example of the installation of some of the components of a gas flow velocity distribution calculation device. [Figure 3] This graph shows an example of the temperature changes of the gas directly above the raw material and the charged raw material at a predetermined position on the raw material charging surface. [Figure 4] This graph shows an example of fitting in Example 1. [Figure 5] This is an explanatory diagram showing the temperature measurement points of the ultrasonic thermometer in Example 2. [Figure 6] This graph shows the measurement results of the gas flow velocity distribution in Example 2. [Modes for carrying out the invention]

[0019] The following detailed description will illustrate embodiments of the present invention with reference to the drawings. In the drawings, identical or similar parts are denoted by the same or similar reference numerals, and redundant descriptions are omitted. Each drawing is schematic and may differ from reality. Furthermore, the embodiments shown below are illustrative of apparatus and methods for realizing the technical idea of ​​the present invention, and the technical idea of ​​the present invention is not limited to the materials, structure, arrangement, etc., of the components 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 patent claims.

[0020] <Device configuration> The configuration of the apparatus in one embodiment of the present invention will be described with reference to Figures 1 and 2. The gas velocity distribution calculation device 1 of the blast furnace 2 in this embodiment is a device that calculates the gas velocity distribution directly above the charging surface of the raw material 3 charged into the blast furnace 2, and comprises a temperature measuring unit 10, a height measuring unit 11, a storage unit 12, a calculation unit 13, and a display unit 14. The gas velocity distribution calculation device 1 has a sonde-less configuration that does not use a furnace mouth sonde.

[0021] The temperature measurement unit 10 measures the gas temperature distribution directly above the charging surface of the raw material 3 charged into the blast furnace 2. Preferably, the temperature measurement unit 10 is a temperature sensor capable of measuring the gas temperature distribution directly above the charging surface of the raw material 3 using a sonderes within 1 minute at the latest. Furthermore, it is preferable that the temperature measurement unit 10 is an ultrasonic thermometer (ultrasonic temperature sensor). In this case, the temperature measurement unit 10 consists of a plurality of ultrasonic temperature sensors installed on the outer circumference of the furnace opening 20 of the blast furnace 2. As the temperature measurement unit 10, for example, the SOMA blast furnace top gas temperature measurement system from TMT GmbH of Germany, which can determine the temperature distribution based on the difference in sound velocity, can be used. Measurement of the gas temperature distribution by the temperature measurement 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 it is preferable to set it to a level that allows for the detection of changes in gas temperature immediately after the charging of the raw material 3. For example, the measurement period of the gas temperature distribution may be 1 min. In the acoustic temperature measurement unit 10, by increasing the number of sound transmitters and receivers installed on the outer circumference of the furnace opening 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 sound velocity and gas temperature using the measured sound velocity. Furthermore, by interpolating the calculated temperature point values, it is possible to determine the overall temperature of the upper surface of the raw material 3 charge. In other words, in this embodiment, the temperature of the charge surface of the raw material 3 is obtained by measurement by the temperature measurement unit 10. Note that the measurement by the temperature measurement unit 10 may include not only measurement of the temperature of temperature points using an acoustic thermometer or the like, but also estimation of the temperature of the calculated temperature points mentioned above.

[0022] The height measurement unit 11 measures the charging height of the raw material 3 charged into the blast furnace 2 at the charging surface. The charging height is the vertical height position of the charging surface. Preferably, the height measurement unit 11 is capable of measuring the charging height of the entire charging surface of the raw material 3 using a sonderless device, and more preferably, it is a scanning distance meter using microwaves or millimeter waves. For example, in the example shown in Figure 2, the height measurement unit 11 is a scanning distance meter installed at the top of the furnace opening 20. Alternatively, for example, the "Lanceless Blast Furnace 3D Profile Meter Milliscanner" manufactured by WADECO can be used for the height measurement unit 11. The measurement of the charging height by the height measurement unit 11 is performed for each batch at the timing when the raw material 3 is 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 and stores the total gas flow rate, which is the gas flow rate discharged from the furnace opening 20 of the blast furnace 2, from a host computer or the like. The total gas flow rate is continuously measured during the operation of the blast furnace 2 by a measuring device installed at or beyond the furnace opening 20. The memory unit 12 stores the gas temperature distribution, charging height, and total gas flow rate as time-series data. The gas temperature distribution stored in the memory unit 12 may also be time-averaged data. In this case, the time averaging of the gas temperature distribution is performed by a calculation means (not shown) or the temperature measurement unit 10. Furthermore, the charging height stored in the memory unit 12 may be the charging thickness for each batch. The charging thickness is the difference in charging height from the state when raw material 3 was previously added to the state after raw material 3 is added again, and is calculated on the charging surface by a calculation means (not shown) or a height measuring unit 11. Furthermore, the storage 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 velocity distribution directly above the charging surface of the raw material 3 based on the gas temperature distribution and the charging height. The calculation unit 13 obtains the gas temperature distribution, charging height, and total gas flow rate from the storage unit 12, and uses this data to calculate the gas velocity distribution directly above the charging surface of the raw material 3. Details of the calculation method of the gas velocity distribution by the calculation unit 13 will be described later. The calculated gas velocity distribution is sent to the storage 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] <Method for calculating gas flow velocity distribution> An example of a method for calculating the gas velocity distribution is shown below. Note that the method for calculating the gas velocity distribution may be the same as the method described in Patent Document 2.

[0027] First, to explain the principle, we will describe the phenomena in the operating process of blast furnace 2. In the operating blast furnace 2, raw materials 3 such as iron ore and coke are intermittently charged into the furnace from the top of the furnace through a swirling chute (not shown). Also in blast furnace 2, high-temperature air blown in from tuyeres 21 installed at the bottom of the furnace reacts with coke and other materials to become a reducing furnace gas, which flows through the gaps in the charged materials to the top of the furnace 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 with the raw materials 3, which are at a lower temperature than room temperature or slightly above room temperature. Therefore, as soon as the raw materials 3 are charged into the blast furnace, the temperature of the furnace gas flowing at the top of the furnace and the charged raw materials 3 change (decrease and rise) due to the effects of heat exchange.

[0028] The gas velocity distribution calculation method according to this embodiment is based on a countercurrent heat transfer model capable of representing the heat exchange described above. The gas velocity distribution is calculated from the temperature change before and after raw material input at the raw material charging timing of raw material 3 and the raw material charging rate (charging thickness) of one batch.

[0029] Figure 3 shows an example of the temperature change of the gas directly above the raw material 3 and the loaded raw material 3 at a predetermined position on the charging surface of the raw material 3. In Figure 3, it represents the gas temperature rise after the previous raw material charging, the subsequent gas temperature drop due to the raw material charging, and the subsequent temperature rise. Using this Figure 3, the calculation method of the gas flow rate distribution estimation method of the present embodiment will be described.

[0030] In Figure 3, let ΔT g be the difference between the lower surface gas temperature and the upper surface gas temperature. The lower surface gas temperature is calculated by extrapolation using the temperature of the raw material 3 charged in the previous time. The details of the estimation method of the lower surface gas temperature will be described later. Also, the lower surface gas temperature uses the temperature rise after the raw material 3 with the raw material thickness used in the calculation is charged.

[0031] Based on the concept of countercurrent heat transfer, assuming that 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) Here, V g : Furnace mouth 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 [m²] 2 / m 3 ] S: Cross-sectional area of ​​the furnace top [m²] 2 ] ΔZ: Thickness of the raw material loaded this time [m]

[0032] From equations (1) and (2), if we let K = h × a × S, we get equation (3) below. ΔT s = T s2 -T s1 = ( T g2 -T g1 )-V g ×C g ×(ΔT g2 -ΔT g1 ) / (K×ΔZ) ···(3) Here, ΔT s : The temperature rise of the charged raw material at Δt [°C]

[0033] On the other hand, since the amount of heat exchanged between the gas and the solid in countercurrent flow during Δt is equal, the following equation (4) holds. C g ×ΔT g ×V g ×Δt=C s ×ΔT s ×V s ×Δt ···(4) Here, C s Specific heat of solids [kcal / kg℃]

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

[0035] In the example shown in Figure 3, the charging of raw material 3 takes approximately the same amount of time as the temperature data sampling period (1 min). Also, assuming that the time difference between t1 and t2 is small, ΔZ = V s Therefore, from equations (3) and (5), we get 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 region near the temperature is given by equation (7) below. 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 stock level height cross-sectional area region is divided around the temperature measurement point, and the flow rate [m 3 Calculate [ / h]. Then, determine K using goal seek calculations or similar methods so that the sum matches the total gas flow rate at the furnace opening.

[0038] By performing the calculations described above, the gas flow velocity at a predetermined position on the charging surface of the raw material 3 can be calculated. In this embodiment, the gas flow velocity distribution of the entire charging surface is calculated by calculating the gas flow velocity at each part of the charging surface of the raw material 3. It is preferable that the position for calculating the gas flow velocity be the height position measured by the temperature measurement unit 10. In other words, if an ultrasonic temperature sensor is used in the temperature measurement unit 10, it is preferable that the position be the installation height of the ultrasonic temperature sensor. Furthermore, if the height measurement unit 11 is a scanning distance meter using microwaves or millimeter waves, the raw material surface can be measured with an accuracy of approximately ±50 mm, and considering the accuracy of raw material charging from above, the charging thickness of the raw material on the charging surface can be measured.

[0039] (Method for estimating the bottom gas temperature) This section describes a method for estimating the bottom gas temperature used in calculating the gas flow velocity. In this embodiment, the bottom gas temperature is determined from the temperature rise curve after raw material charging. The temperature rise curve is determined using temperature rise data, which is time-series data of the gas temperature distribution between past raw material charging cycles. Furthermore, the temperature rise curve is determined from the temperature changes of at least two past cycles (the temperature rise process after raw material charging).

[0040] When time-series data of furnace port temperature acquired by an ultrasonic thermometer is simply processed using methods such as moving averages or filters, it can be affected by noise-like fluctuations between batches (between the charging of raw material 3), resulting in a phenomenon that differs from the intended one. Considering the physical characteristics during raw material charging as described above, it is considered appropriate to use a function that is a downward-convex, first-order increasing function that converges to a constant value in infinite time. Therefore, the temperature rise curve can be obtained by extracting the min-max temperature data between charging and fitting a first-order increasing function to the temperature values ​​during that period. The temperature rise curve can be obtained, for example, using equation (8) below. Here, the gain G and time constant T are adjusted to fit the curve 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 thermocouples on furnace mouth sondes used conventionally, so it can detect even small temperature fluctuations. Furthermore, during the charging process between charging batches, a flow of raw material 3 occurs during charging, increasing the airflow resistance where raw material 3 is charged and decreasing where raw material 3 is not charged. Also, because raw material 3 is charged while swirling, the flow rate distribution and gas temperature may change slightly during the charging process (midway). Due to these factors, it is thought that the temperature does not increase uniquely between charging batches but fluctuates up and down. Measurement by the height measurement unit 11 during charging can accurately acquire data before and after batches at times when no raw material is being charged. For this reason, obtaining a representative temperature change that increases uniquely between batches (from the start to the end of raw material charging), which is necessary for flow velocity calculation, is important for improving the accuracy of gas flux distribution estimation. This can be achieved by fitting 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, this raw material charging surface can be any area, but it is preferable that it be the entire charging surface.

[0043] <Variation> Although the present invention has been described above with reference to specific embodiments, this description is not intended to limit the invention. By referring to the description of the present invention, those skilled in the art will also see other embodiments of the invention, including various modifications, in addition to the disclosed embodiments. Accordingly, the embodiments of the invention described in the claims should be understood to include embodiments that include these modifications described herein, either individually or in combination.

[0044] For example, in the above embodiment, when determining the gas velocity distribution, the velocity at each part of the charging surface was determined, but the present invention is not limited to such examples. In the operation of the blast furnace 2, it is desirable to make the gas velocity distribution in the circumferential direction (at the same radius position) as uniform as possible, so the state can also be judged from the gas velocity balance in the circumferential direction. For this reason, only the relative balance of the gas velocity at the charging surface may be determined. In this case, it is not necessary to apportion the total gas flow rate of the furnace opening 20 in the above embodiment, nor is it necessary to use the total gas flow rate of the furnace opening 20.

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

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

[0047] According to the configuration described in (1) above, by calculating the gas velocity distribution at the charging surface of raw material 3, local changes in flow velocity can also be measured.

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

[0049] Here, in the method using a furnace port sonde as described in Patent Document 2, temperature measurement at multiple points becomes possible by increasing the number of furnace port sondes (arms). However, this interferes with the measurement of the profile meter that measures the charging thickness of the raw material, thus hindering accurate measurement of the charging surface by the profile meter. Similarly, in order to measure the charging thickness of the raw material at many locations using a profile meter with a furnace port sonde, one possible method is to charge the furnace port sonde equipped with a profile meter from multiple directions and take measurements. However, in this case, it interferes with the measurement of raw material charging and furnace port gas temperature, and in the study in Patent Document 2, measurement was only taken at one location in the radial direction, making it difficult to accurately calculate the entire flow velocity distribution. On the other hand, according to the configuration of (2) above, since arms installed directly above the raw material charging surface such as a furnace port sonde are not used, the gas flow velocity distribution on the charging surface can be measured without interfering with other operations such as raw material charging. In addition, interference between the temperature measurement unit 10 and the height measurement unit 11 can also be prevented.

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

[0051] According to the configuration described in (3) above, compared to methods such as Patent Document 2, which assume thermocouples with slow temperature response, it is possible to measure changes in the furnace opening in a short time, and thus measure the gas flow velocity distribution inside the furnace with higher accuracy.

[0052] (4) In the gas velocity distribution calculation device 1 of any one of the blast furnaces 2 described in (1) to (3) above, the calculation unit 13 calculates the gas velocity at each part of the charging surface of the raw material 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. As the extrapolated value, the calculation unit 13 uses a temperature rise curve obtained by fitting a first-order increasing function to the temperature rise data between past raw material charges at each part of the charging surface.

[0053] According to the configuration described in (4) above, highly accurate values ​​can be estimated as extrapolations, allowing for more accurate measurement of the gas velocity distribution inside the reactor.

[0054] (5) A method for calculating the gas velocity distribution of a blast furnace according to one aspect of the present invention involves measuring the gas temperature distribution directly above the charging surface of raw materials intermittently charged into the blast furnace 2, measuring the charging height of the raw materials at the charging surface, and calculating the gas 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 velocity distribution of the blast furnace described in (5) above, a furnace mouth sonde is not used when measuring the gas temperature distribution and when measuring the charging height.

[0056] (7) In the method for calculating the gas velocity distribution of a blast furnace described in (5) or (6) above, an ultrasonic thermometer is used when measuring the gas temperature distribution, and a scanning rangefinder using microwaves or millimeter waves is used when measuring the charging height.

[0057] (8) In any one of the blast furnace gas velocity distribution calculation methods described in (5) to (7) above, when calculating the gas velocity distribution, the gas velocity at each part of the raw material charging surface 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. As the extrapolated value, a temperature rise curve is used at each part of the charging surface, obtained by fitting a first-order increasing function to the temperature rise data between past raw material charges.

[0058] The configurations described in (5) to (8) above will produce the same effects as the configurations described in (1) to (4) above.

[0059] (9) A method for operating a blast furnace according to one aspect of the present invention is provided, which, when the blast furnace 2 is in operation, calculates the gas velocity distribution directly above the charging surface of the raw materials charged into the blast furnace using the blast furnace gas velocity distribution calculation method described in any one of (5) to (8) above. [Examples]

[0060] We will now describe Example 1, which was implemented by the present inventors. In Example 1, a temperature rise curve was obtained by applying and fitting equation (8) to a single temperature point measured by an ultrasonic thermometer, which is the temperature measurement unit 10. The temperature data used was inter-batch data, and data from after raw material charging to just before the next charging was extracted and used. Although this data is inter-batch data, it was confirmed that the data itself does not increase uniquely, but rather decreases midway before rising. The calculation objective can be satisfied if the average temperature rise for all raw materials charged between batches is known. Figure 4 shows the results of the example. As shown in Figure 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 temperature, especially extrapolated temperature. [Examples]

[0061] In Example 2, the same calculation as in Example 1 was applied to each temperature measurement point of the ultrasonic thermometer to calculate the gas flow velocity at each measurement point. The total gas flow velocity value was then apportioned according to the ratio of the gas flow velocity values ​​at each measurement point to determine the gas flow velocity distribution. The measurement points consisted of 57 points in total, as shown in Figure 5 (circles indicate measurement points, 7 points in the radial direction × 8 points in the circumferential direction + 1 center point).

[0062] Figure 6 shows the calculation results of the gas flow rate distribution in Example 2. In Figure 6, values ​​for display were calculated using interpolation except for the temperature measurement points. These results match the assumed so-called W-shaped flow velocity distribution, and it was also confirmed that the balance in the circumferential direction was slightly different. From these results, it was confirmed that the gas flow velocity distribution measuring device and gas flow velocity distribution measuring method of the blast furnace according to the above embodiment can measure gas flow velocity with high accuracy. Furthermore, by using an ultrasonic thermometer, it is possible to measure the temperature at even more measurement points (for example, measurement points shifted radially or circumferentially from the measurement points in Figure 5), so that the gas flow velocity can be measured with even higher accuracy. [Explanation of Symbols]

[0063] 1. Gas flow velocity distribution calculation device 10 Temperature measurement unit 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. The blast furnace has a sonic thermometer that measures time-series data of the gas temperature distribution directly above the entire charging surface of the raw materials intermittently charged into the blast furnace, and a temperature measurement unit that does not use a furnace mouth sonde, A height measurement unit that does not use a furnace mouth sonde has a scanning distance meter using microwaves or millimeter waves to measure the charging height of the raw material across the entire charging surface for each batch at each timing of the charging of the raw material, A calculation unit that calculates the gas flow velocity distribution directly above the charging surface of the raw material based on the gas temperature distribution and the charging height, Equipped with, A blast furnace gas velocity distribution calculation device, wherein the calculation unit calculates the gas velocity at each part of the raw material charging surface based on time-series data of the gas temperature at each part of the charging surface, extrapolated values ​​of the gas temperature at each part of the charging surface based on a temperature rise curve obtained by fitting a first-order increasing function with a time constant to temperature rise data, which is time-series data that increases while fluctuating up and down between past chargings of the raw material, and charging thickness calculated from the change in the charging height at each part of the charging surface.

2. Time-series data of the gas temperature distribution directly above the entire charging surface of the raw materials intermittently charged into the blast furnace was measured using an ultrasonic thermometer, without using a furnace mouth sonde. The charging height of the raw material is measured for each batch at each timing of the charging, across the entire charging surface, using a scanning distance meter with microwave or millimeter waves, without using a furnace mouth sonde. Based on the gas temperature distribution and the charging height, the gas flow velocity distribution directly above the charging surface of the raw material is calculated. A method for calculating the gas velocity distribution of a blast furnace, wherein when calculating the gas velocity distribution, the gas velocity at each part of the charging surface of the raw material is calculated based on time-series data of the gas temperature at each part of the charging surface, extrapolated values ​​of the gas temperature at each part of the charging surface based on a temperature rise curve obtained by fitting a first-order increasing function with a time constant to temperature rise data, which is time-series data that increases while fluctuating up and down between past chargings of the raw material, and the charging thickness calculated from the change in the charging height at each part of the charging surface.

3. A method for operating a blast furnace, comprising calculating the gas velocity distribution directly above the charging surface of raw materials charged into the blast furnace using the blast furnace gas velocity distribution calculation method described in claim 2, during the operation of the blast furnace.

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