Dust generation rate estimation device and dust generation rate estimation method

Abstract

To provide a dust generation speed estimation device that can continuously operate, has a small maintenance burden, and can estimate a dust generation speed with high accuracy.SOLUTION: A dust generation speed estimation device comprises: a spectral luminance acquisition unit that sets a plurality of optical paths including a combustion flame generated in an opening of a refining furnace and having different lengths, and for each of the optical paths, acquires spectral luminance of a radiation spectrum at a target wavelength in the optical path; a combustion flame temperature estimation unit that estimates a temperature of the combustion flame; a black body radiation luminance operation unit that calculates black body radiation luminance at the estimated temperature of the combustion flame; a spectral emissivity operation unit that calculates spectral emissivity from a ratio between the spectral luminance and the black body radiation luminance; a spectral emissivity ratio operation unit that calculates a spectral emissivity ratio that is a ratio between two spectral emissivity ratios; and a dust generation speed estimation unit that, on the basis of a relational expression determined in advance, estimates a generation speed of dust.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a dust generation rate estimation device and a dust generation rate estimation method. [Background technology]

[0002] Molten iron obtained from a blast furnace is refined in a converter. In the refining process in the converter, processes such as decarburization and desiliconization are carried out, and the height of the main lance, the oxygen flow rate, the amount of auxiliary materials charged, etc. are controlled according to the progress of these processes. In controlling such converters, a technology that utilizes the emission spectrum of the combustion flame of the converter has been known.

[0003] Patent documents 1 and 2 disclose a method for analyzing converter exhaust gas in which light emission in a converter exhaust gas flue is analyzed and the component concentrations of the exhaust gas and dust in the flue are calculated in order to estimate decarburization and other conditions during the refining process with high accuracy.

[0004] Patent Document 3 discloses a spectroscopic characteristic measuring device including an imaging spectroscopic device that acquires light emitted by an object as spectroscopic information, a two-dimensional imaging device that captures an image of a two-dimensional area of ​​the object, and a calculation device that determines a range from which the imaging spectroscopic device acquires spectroscopic information based on the image captured by the two-dimensional imaging device. Patent Document 3 also describes that this technology is used to measure the spectroscopic characteristics of a flame generated from a refining furnace and control the refining furnace.

[0005] Patent Documents 4 and 5 disclose techniques for measuring the emission spectrum of a furnace-mouth combustion flame blowing out from the furnace mouth of a converter, calculating the change over time in emission intensity at a measured wavelength range of 580 to 620 nm, estimating changes in conditions inside the furnace based on the calculated changes in emission intensity over time, and estimating the end point of the desiliconization reaction and the carbon concentration of molten iron based on the estimated changes in conditions inside the furnace.

[0006] Patent Document 6 discloses a technique for estimating the carbon concentration in molten metal based on performance information including information on the optical characteristics of the throat of a converter. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 62-90524 [Patent Document 2] Japanese Patent Application Publication No. 62-90525 [Patent Document 3] International Publication No. 2019 / 168141 [Patent Document 4] JP 2020-105610 A [Patent Document 5] JP 2020-105611 A [Patent Document 6] International Publication No. 2019 / 220800 Summary of the Invention [Problem to be solved by the invention]

[0008] Incidentally, the amount of dust generated during converter blowing amounts to 1% to several percent of the total molten iron, so reducing the amount of dust generated during converter operation directly leads to cost reduction. However, the dust generation rate estimation means proposed so far are a method of manually sampling the amount of dust or a method of continuously measuring the amount of dust using dust collection water or exhaust gas piping, and maintenance including periodic replacement of parts and removal and cleaning of parts is required in areas that are rarely visited during normal operation. Therefore, it is difficult to constantly perform such a laborious method in a converter that is constantly operated. In addition, the techniques of Patent Documents 1 to 6 do not estimate the amount of dust (dust generation rate).

[0009] Therefore, in consideration of the above-mentioned situation, an object of the present disclosure is to provide a dust generation rate estimation device and a dust generation rate estimation method that are capable of continuous operation, have a small maintenance load, and can estimate the dust generation rate with high accuracy. [Means for solving the problem]

[0010] The present disclosure provides, as one means for solving the above-mentioned problems, an apparatus for estimating the generation rate of dust generated during the operation of a refining furnace, the apparatus including a combustion flame generated at an opening of the refining furnace, a plurality of optical paths having different lengths are set, and the apparatus includes a spectral radiance acquisition unit that acquires, for each optical path, the spectral radiance of a radiation spectrum at a wavelength of interest in the optical paths, a combustion flame temperature estimation unit that estimates, for each optical path, the temperature of the combustion flame at the time the spectral radiance acquisition unit acquires the spectral radiance, and a combustion flame temperature estimation unit that estimates, for each optical path, the blackbody radiance of the wavelength of interest at the estimated combustion flame temperature. a spectral emissivity calculation unit that calculates a spectral emissivity for each optical path from the ratio of the spectral luminance acquired by the spectral luminance measurement unit and the blackbody radiance calculated by the blackbody radiance calculation unit; a spectral emissivity ratio calculation unit that selects two of the calculated spectral emissivities and calculates a spectral emissivity ratio, which is the ratio between these; and a dust generation rate estimation unit that estimates the dust generation rate based on a relational equation between the spectral emissivity ratio and the dust generation rate that has been obtained in advance.

[0011] In the above-mentioned dust generation rate estimation device, the optical path may include an optical path that includes the lance of the refining furnace on an extension line of the optical path, and an optical path that does not include the lance of the refining furnace on an extension line of the optical path.

[0012] As one means for solving the above problem, the present disclosure provides a refining furnace that controls the refining furnace based on the dust generation rate estimated by the above dust generation rate estimation device.

[0013] The present disclosure provides, as one means for solving the above-mentioned problems, a method for estimating a generation rate of dust generated during the operation of a refining furnace, comprising: a spectral radiance acquisition step of setting a plurality of light paths having different lengths, each of which includes a combustion flame generated at an opening of the refining furnace, and acquiring, for each light path, the spectral radiance of a radiation spectrum at a wavelength of interest in the light path; a combustion flame temperature estimation step of estimating, for each light path, the temperature of the combustion flame at the time when the spectral radiance was acquired in the spectral radiance acquisition step; and a combustion flame temperature estimation step of estimating, for each light path, the blackbody radiance at the wavelength of interest at the estimated combustion flame temperature. a spectral emissivity calculation step of calculating a spectral emissivity for each optical path from the ratio between the spectral luminance acquired in the spectral luminance measurement step and the blackbody radiance calculated in the blackbody radiance calculation step; a spectral emissivity ratio calculation step of selecting two of the calculated spectral emissivities and calculating a spectral emissivity ratio, which is the ratio between them; and a dust generation rate estimation step of estimating the dust generation rate based on a relational equation between the spectral emissivity ratio and the dust generation rate that has been obtained in advance.

[0014] In the above dust generation rate estimation method, the light paths may include light paths that include the lance of the refining furnace on an extension line of the light path, and light paths that do not include the lance of the refining furnace on an extension line of the light path.

[0015] As one means for solving the above problem, the present disclosure provides a method for controlling a refining furnace, which controls the refining furnace based on the dust generation rate estimated by the above dust generation rate estimation method. Effect of the Invention

[0016] According to the present disclosure, continuous operation is possible, the maintenance load is small, and the dust generation rate can be estimated with high accuracy. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic diagram of a dust generation rate estimation device 100. [Diagram 2]FIG. 2 is a diagram for explaining optical paths (1) to (3) in the first embodiment. [Diagram 3] 1 shows the relationship between the spectral emissivity ratio and the amount of filter collected per unit time in Example 1. [Figure 4] 11 is a diagram showing a relationship between the filter collection amount per unit time estimated from the spectral emissivity ratio in Example 1 and the actual filter collection amount per unit time. [Diagram 5] 13 shows the relationship between the spectral emissivity ratio and the actually measured dust generation rate (index value) and the elapsed time in Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The inventors of the present invention measured the combustion flame generated at the opening (furnace port frame) of the refining furnace with a spectroscope and confirmed that the radiation spectrum was the main component. The spectral emissivity can be calculated from the ratio of the measured luminance at the wavelength of interest of this radiation spectrum to the blackbody radiance calculated by Planck's law. If no luminous object is included in the measurement area, the measured value of the spectral emissivity is 0, whereas if the measurement area is seemingly filled with luminous objects, it is equivalent to surface emission, and the measured value of the spectral emissivity coincides with the spectral emissivity as a property of the luminous object. In this way, since the measured spectral emissivity depends on the concentration of the luminous object (dust in the case of the furnace port combustion flame) in the measurement area, the inventors of the present invention conceived that the generation rate of dust in the refining furnace can be estimated based on the spectral emissivity. Then, in order to confirm the success or failure of the idea, the inventors of the present invention used a test converter to evaluate the relationship between the spectral emissivity calculated from the radiation spectrum of the combustion flame and the amount of dust generated collected from a filter, and confirmed that there is a good correlation between the spectral emissivity and the amount of dust generated.

[0019] On the other hand, we also found that it is difficult to eliminate factors that affect the measurement results of spectral radiance when estimating the dust generation rate based on spectral emissivity, such as (A) the effect on spectral emissivity of the type of particles that make up the dust and their surface conditions, (B) the effect of dust and water vapor floating on the light path (from the focusing part to the furnace opening), and (C) the effect of correction factors of the optical system (lens transmittance and optical fiber characteristics).

[0020] Therefore, the inventors have found that by taking the ratio of the spectral emissivity obtained from a plurality of measurement points with different effective optical path lengths, it is possible to eliminate these effects and improve the estimation accuracy. The dust generation rate estimation device and dust generation rate estimation method of the present disclosure have been invented based on this finding. Below, the dust generation rate estimation device and dust generation rate estimation method of the present disclosure will be described respectively.

[0021] [Dust generation rate evaluation device] The dust generation rate evaluation device of the present disclosure will be described using a dust generation rate evaluation device 100 (hereinafter, sometimes referred to as "device 100") which is one embodiment. A schematic diagram of the device 100 is shown in FIG.

[0022] The device 100 is an apparatus for estimating the generation rate of dust generated during the operation of a refining furnace 1, and includes a spectral radiance acquisition unit 10 and a calculation unit 20 that performs calculations for estimating the dust generation rate.

[0023] The spectral radiance acquisition unit 10 includes a combustion flame generated at the opening 2 of the refining furnace 1, and sets a plurality of optical paths with different lengths, and acquires the spectral radiance of the radiation spectrum at a wavelength of interest for each optical path. The number of optical paths set may be only two.

[0024] The spectral radiance acquisition section 10 includes a light acquisition section 11 and a spectroscope 12, and the light acquisition section 11 and the spectroscope 12 are connected by an optical fiber or the like. Such a spectral radiance acquisition section 10 has a known configuration.

[0025] The spectral radiance acquisition unit 10 may include a plurality of light acquisition units 11 and spectrometers 12 since it acquires the spectral radiance of the radiation spectrum at the wavelength of interest from a plurality of light paths having different optical path lengths. FIG. 1 shows the spectral radiance acquisition unit 10 including two light acquisition units 11 and two spectrometers 12. This allows the spectral radiance of the wavelength of interest for each light path to be measured simultaneously. On the other hand, when there is only one light acquisition unit 11 and one spectrometer 12, the spectral radiance is measured sequentially for each light path, but the measurement interval needs to be as short as possible. For example, within 10 seconds. Methods for sequentially measuring the spectral radiance include a method of mechanically or electronically switching between a plurality of light paths, and a method of measuring by moving the spectral radiance acquisition unit 10 (or the light acquisition unit 11) using a stage.

[0026] The light acquisition unit 11 may be disposed at a position where it can acquire light emitted from the combustion flame generated at the opening 2 of the refining furnace. In addition, by using a condenser lens in the light acquisition unit 11 to clarify the measurement range, it is possible to improve the accuracy of acquiring the spectral radiance.

[0027] The spectral radiance acquisition unit 10 acquires the spectral radiance of the radiation spectrum at a wavelength of interest from the combustion flame generated at the opening 2 of the refining furnace 1, and usually acquires a spectrum including these pieces of information. Then, the spectral radiance acquisition unit 10 transmits the spectral radiance information to the calculation unit 20. The wavelength range of the acquired spectrum is, for example, 350 nm to 1000 nm.

[0028] Here, the radiation spectrum at the wavelength of interest will be described. The spectrum obtained from the emission of a combustion flame includes a radiation spectrum, a molecular emission spectrum, an atomic emission spectrum, and the like. Among these, a wavelength that includes a radiation spectrum and does not include a molecular emission spectrum and an atomic emission spectrum is selected. For example, a wavelength that includes only a radiation spectrum is selected. The wavelength selected in this manner is the wavelength of interest. For example, the molecular emission spectrum of 580 nm to 620 nm caused by the generation and disappearance of FeO, the atomic emission spectrum of 589 nm of Na, and the atomic emission spectrum of 767 nm to 770 nm of K are not preferable as the wavelength of interest. However, if the wavelength resolution of the spectrometer is high, it is possible to eliminate the influence of molecular emission and atomic emission even in the above range.

[0029] In addition, the selection of the optical path set in the spectral luminance acquisition unit 10 will be described. In principle, any optical path may be selected as long as it includes the combustion flame generated at the opening 2 of the refining furnace 1 and has a different length. However, if there is almost no difference in the optical path length of the selected optical path, the spectral emissivity ratio described later will be close to 1, and the dust generation rate calculated from it may have low accuracy. In addition, it is necessary to consider that the dust concentration (volume ratio in the space) is unlikely to be uniform throughout the combustion flame at the converter furnace mouth. Simply speaking, it is expected that the dust concentration is higher closer to the center of the furnace mouth and lower closer to the edge. Therefore, it is preferable to select an optical path that includes the lance 3 of the refining furnace 1 on the extension line of the optical path (effective optical path length: 1 / 2 of the furnace diameter) and an optical path that does not include the lance 3 of the refining furnace 1 on the extension line of the optical path. More preferably, an optical path including the lance 3 of the refining furnace 1 on the extension line of the optical path and an optical path slightly shifted from the optical path and not including the lance 3 of the refining furnace 1 on the extension line of the optical path but close to the lance 3 (effective optical path length: furnace diameter to 0.8 x furnace diameter, preferably effective optical path length: furnace diameter to 0.9 x furnace diameter, more preferably effective optical path length: furnace diameter) are selected. This makes it possible to measure locations with substantially the same dust concentration while having an optical path difference.

[0030] In the present disclosure, the spectral radiance acquisition unit 10 is not limited to the form shown in Fig. 1. For example, a photosensor capable of acquiring the spectral radiance of a specific wavelength using an optical element such as a bandpass filter may be used.

[0031] The calculation unit 20 estimates the generation speed of dust generated during the operation of the refining furnace based on the spectral radiance of the wavelength of interest transmitted from the spectral radiance acquisition unit 10. The calculation unit 20 is a known computer equipped with a CPU, RAM, ROM, a predetermined interface, etc.

[0032] The calculation unit 20 includes a combustion flame temperature estimation unit that estimates the temperature of the combustion flame for each optical path when the spectral radiance acquisition unit 10 acquires the spectral radiance; a blackbody radiation luminance calculation unit that calculates the blackbody radiance of a wavelength of interest at the estimated combustion flame temperature for each optical path; a spectral emissivity calculation unit that calculates the spectral emissivity for each optical path from the ratio of the spectral radiance acquired by the spectral radiance measurement unit and the blackbody radiance calculated by the blackbody radiation luminance calculation unit; a spectral emissivity ratio calculation unit that selects two of the calculated spectral emissivities and calculates a spectral emissivity ratio, which is the ratio between these; and a dust generation rate estimation unit that estimates the dust generation rate based on a relational equation between the spectral emissivity ratio and the dust generation rate that has been obtained in advance.

[0033] The combustion flame temperature estimation unit estimates the temperature of the combustion flame for each optical path when the spectral luminance acquisition unit 10 acquires the spectral luminance. The reason for estimating the temperature of the combustion flame for each optical path is that the combustion flame temperature (radiation temperature) varies spatially. When the spectral luminance acquisition unit 10 acquires a spectral spectrum, the temperature of the combustion flame can be estimated from the spectral spectrum using the principle of a two-color thermometer. In addition, the temperature of the combustion flame may be measured using a separate radiation thermometer. In this case, it is necessary to measure the temperature of the combustion flame simultaneously with the time when the spectral luminance acquisition unit 10 acquires the spectral luminance. Simultaneous does not have to be completely simultaneous. For example, an error within 1 second is acceptable. Preferably, the temperature of the combustion flame is estimated from the spectral spectrum using the principle of a two-color thermometer.

[0034] The blackbody radiation luminance calculation unit calculates the blackbody radiation luminance of the wavelength of interest at the estimated combustion flame temperature for each optical path. The blackbody radiation luminance of the wavelength of interest can be calculated using Planck's law.

[0035] The spectral emissivity calculation unit calculates the spectral radiance (M0) acquired by the spectral radiance measurement unit and the blackbody radiation radiance (M B ) to the spectral emissivity (M0 / M B ) is calculated for each optical path.

[0036] Here, the term "spectral emissivity" is a concept that includes both the absolute value of the spectral emissivity and a value proportional to the spectral emissivity. This is because using a value proportional to the spectral emissivity has little effect on the evaluation of the dust generation rate. The value proportional to the spectral emissivity is the product of the absolute value of the spectral emissivity and a predetermined coefficient that depends on the measurement system. Specifically, the theoretical formula of the temperature-dependent coefficient (relative value) of the "spectral luminance of blackbody radiation" at the wavelength of interest is calculated according to Planck's law, and the "spectral luminance obtained by measurement" is divided by the temperature-dependent coefficient obtained by substituting the "measured radiation temperature (combustion flame temperature)" into the theoretical formula, thereby obtaining a value proportional to the spectral emissivity. However, the evaluation accuracy is improved by obtaining the coefficient that depends on the measurement system in advance using a blackbody furnace and obtaining the absolute value of the spectral emissivity. For example, the absolute value of the spectral emissivity can be obtained by previously obtaining the attenuation rate in a standard blackbody furnace using an apparatus with the same configuration as the apparatus 100.

[0037] The spectral emissivity ratio calculation unit selects two of the calculated spectral emissivities and calculates a spectral emissivity ratio, which is the ratio between these.

[0038] The dust generation speed estimating section estimates the dust generation speed based on a relational expression between the spectral emissivity ratio and the dust generation speed that has been obtained in advance.

[0039] The spectral emissivity calculated by the spectral emissivity calculation unit is the average spectral emissivity within the light collection range. The spectral emissivity indicates the amount of luminous body (dust) occupying the light collection range when the spectral luminance of the wavelength of interest is acquired by the spectral brightness acquisition unit 10. If the amount of dust is large, the spectral emissivity increases, and if the amount of dust is small, the spectral emissivity decreases. If the optical path length is long, the amount of luminous body occupying the light collection range increases, so the spectral emissivity increases, while if the optical path length is short, the spectral emissivity decreases. If the overlap between dust particles in front and behind can be ignored, the optical path length and the measured spectral emissivity are proportional. On the other hand, if the volume ratio of dust particles occupying the space increases, the overlap between dust particles cannot be ignored, and the measured spectral emissivity and the dust generation speed are no longer proportional. In this way, the degree of deviation from the proportional relationship, that is, the magnitude of nonlinearity, correlates with the volume ratio of dust.

[0040] Whether the dust overlap can be ignored depends on the depth (optical path length) of the light collection range. This is because the longer the depth and the more dust present in the light collection range, the stronger the influence of the dust overlap. Therefore, in the device 100, the spectral luminance is measured at multiple points with different depths in the light collection range, and the magnitude of the influence of the dust overlap can be measured by comparing the depth ratio. Then, the spectral emissivity ratio based on the two optical paths is calculated, and the dust generation rate is estimated from this. In this way, the spectral emissivity ratio is calculated using the nonlinearity of the dust generation rate based on the dust overlap. This eliminates the above-mentioned (A) influence on the spectral emissivity of the type of particles constituting the dust and the surface condition, and (B) the influence of dust and water vapor floating on the optical path (from the light collection part to the furnace opening). In addition, it is also possible to eliminate the influence of (C) the correction factors of the optical system (lens transmittance and optical fiber characteristics).

[0041] When multiple similar optical paths are selected, the above-mentioned (A) influence on the spectral emissivity of the type of particles constituting the dust and the surface condition, and (B) influence of dust and water vapor floating on the optical path (from the light collecting section to the furnace opening) can be considered to be equal for each optical path, so that factors (A) and (B) can be eliminated by taking the ratio. Furthermore, by using the same equipment configuration for the spectral radiance acquisition section 10 and the light acquisition section 11, factor (C) can be eliminated, and detailed correction of the measurement system becomes unnecessary. Furthermore, even if the spectral radiance acquisition section 10 and the light acquisition section 11 do not have to be the same equipment configuration, detailed correction of the measurement system becomes unnecessary if they are configured by combining equipment with known optical characteristics.

[0042] As described above, when estimating the dust generation rate from the spectral emissivity ratio, a relational expression between the spectral emissivity ratio and the dust generation rate that has been obtained in advance is used. Such an empirical expression (relational expression) can be obtained experimentally or by simulation. For example, an empirical expression in which the spectral emissivity ratio and the gas passing speed near the furnace diameter and the furnace mouth of the refining furnace 1 are variables may be used. Since the gas passing speed is equivalent to the gas generation rate (gas generation amount) based on the amount of oxygen blown from the top and bottom, the gas generation rate may be used as a variable in the empirical expression.

[0043] On the other hand, in regions where the dust generation rate is low and the dust concentration in space is small, the spectral emissivity is proportional only to the optical path length, so the spatial concentration of dust cannot be obtained. Also, if the dust concentration in space is too high, dust will be present throughout the entire light collection range and will be saturated (almost equivalent to uniform surface emission). Therefore, the ratio of the spectral emissivity for each optical path will be almost 1 and will not change. In this way, the method disclosed herein is effective for intermediate dust concentration regions.

[0044] The intermediate dust concentration range depends not only on the size of the furnace and various blowing conditions including the oxygen supply conditions, but also on the dust properties, particle size distribution, etc., and is therefore considered to be unique to each furnace and cannot be determined only by the operable conditions. Therefore, it is difficult to specify the intermediate dust concentration range, and it is necessary to actually measure and create an empirical formula. The inventors have determined that the intermediate dust concentration range is at least in the range of furnace diameters of 0.5 m to 6.5 m and dust concentration of 1 g / m 3 More than 200g / m 3 It has been found that the techniques disclosed herein are effective in the following areas:

[0045] Here, the range of the spectral emissivity ratio will be described. When the optical paths related to the two spectral emissivities used in the spectral emissivity ratio are optical path A and optical path B, and the longer optical path is optical path A, the spectral emissivity ratio is in the range of the ratio of the lengths of optical paths A and B (B / A) to less than 1. It is preferably less than 1, in the range of B / A to B / A + (1 - B / A) x 0.9. By estimating the dust generation speed based on the spectral emissivity ratio included in this range, the dust generation speed can be estimated with high accuracy.

[0046] The dust generation rate estimation device of the present disclosure has been described above using the device 100 as one embodiment. The dust generation rate estimation device of the present disclosure acquires the spectral luminance of a predetermined wavelength of the combustion flame and estimates the dust generation rate based on the spectral luminance. Therefore, unlike the conventional dust generation rate estimation method, it is configured to be able to operate continuously. In addition, the dust generation rate estimation device of the present disclosure has a high degree of freedom in terms of installation location, as long as the measurement device is placed at a position where the light emission of the combustion flame generated at the opening of the refining furnace can be acquired, and can be installed at a position where the operator can easily access it. The dust generation rate estimation device of the present disclosure only requires maintenance of the part (light acquisition part) that acquires the spectral luminance of the combustion flame, and does not need to be removed, so the maintenance load is small. For example, it is sufficient to blow off the dust near the light acquisition part with an air duster or the like, and the required maintenance frequency can be reduced to about once per day or less. In addition, by devising a method to prevent dust from adhering to and accumulating on the light acquisition part, it is possible to further reduce the frequency, for example, to once per month or less. Therefore, the maintenance load can be significantly reduced compared to the conventional method. Furthermore, the dust generation rate estimation device of the present disclosure obtains a plurality of spectral emissivities based on the spectral luminance of the radiation spectrum at the wavelength of interest, and calculates the spectral emissivity ratio from these. The inventors have found that in a region where the gas generation rate is high (a region of intermediate dust concentration), there is a high correlation between the spectral emissivity ratio and the dust generation rate. Therefore, by using the spectral emissivity ratio, the dust generation rate can be estimated with high accuracy. As described above, the dust generation rate estimation device of the present disclosure can operate continuously, has a small maintenance load, and can estimate the dust generation rate with high accuracy.

[0047] [Refining furnace] The refining furnace of the present disclosure controls the refining furnace based on the dust generation rate estimated by the dust generation rate estimation device of the present disclosure. The refining furnace is a furnace for refining molten iron, such as a converter. The control of the refining furnace means, for example, controlling the refining furnace so as to reduce the dust generation rate. Specific means include, for example, changing the height of the lance of the refining furnace, changing the amount of oxygen blown from the top and bottom, and changing the timing and rate of feeding auxiliary materials. The refining furnace of the present disclosure makes it possible to reduce the amount of dust generation.

[0048] [Dust generation rate evaluation method] The dust generation rate estimation method disclosed herein is a method for estimating the generation rate of dust generated during the operation of a refining furnace, and includes a spectral radiance acquisition process for setting a plurality of light paths of different lengths that include a combustion flame generated at an opening of the refining furnace, and acquiring, for each light path, the spectral radiance of a radiation spectrum at a wavelength of interest in the light paths; a combustion flame temperature estimation process for estimating, for each light path, the temperature of the combustion flame at the time the spectral radiance was acquired in the spectral radiance acquisition process; a blackbody radiance calculation process for calculating, for each light path, the blackbody radiance at the wavelength of interest at the estimated combustion flame temperature; a spectral emissivity calculation process for calculating, for each light path, a spectral emissivity from the ratio of the spectral radiance acquired in the spectral radiance measurement process and the blackbody radiance calculated in the blackbody radiance calculation process; a spectral emissivity ratio calculation process for selecting two of the calculated spectral emissivities and calculating a spectral emissivity ratio, which is the ratio between them; and a dust generation rate estimation process for estimating the dust generation rate based on a relational equation between the spectral emissivity ratio and the dust generation rate that has been determined in advance. The details of the dust generation rate estimation method of the present disclosure have been explained in the dust generation rate estimation device of the present disclosure, so explanation thereof will be omitted here.

[0049] [Method of controlling refining furnace] The refining furnace control method of the present disclosure controls the refining furnace based on the dust generation rate estimated by the dust generation rate estimation method of the present disclosure. The contents of the refining furnace control method of the present disclosure have been described in the refining furnace of the present disclosure, so description thereof will be omitted here. EXAMPLES

[0050] The present disclosure will now be further described with reference to examples.

[0051] [Example 1] The dust generation rate was estimated using a 2-ton small converter. The light paths (1) to (3) were used (see Fig. 2). (1) The lance is not included in the extension of the optical path, but the optical path is close to the lance (effective optical path length: furnace diameter) (2) Optical path including the lance on the extension line of the optical path (effective optical path length: 1 / 2 of the furnace diameter) (3) The optical path does not include the lance on the extension line of the optical path (effective optical path length: 1 / 4 of the furnace diameter) Although the effective optical path length in (1) is not exactly the same as the furnace diameter, it is considered to be the same as the furnace diameter to simplify the calculation.

[0052] Here, the same optical system (collecting lens, etc.) was used for all the spectral radiance acquisition units. The spectral radiance acquisition unit also acquired the spectral radiance at the wavelength of interest, 700 nm. The temperature of the combustion flame was estimated using the principle of a two-color pyrometer based on the radiance ratio of wavelengths 700 nm and 900 nm. Then, the spectral emissivity was calculated for each optical path from the ratio of the calculated spectral radiance to the blackbody radiance, and the spectral emissivity ratios (2) / (1) and (3) / (1) were calculated. Furthermore, the converter exhaust gas was sampled at regular intervals and passed through a filter to collect dust.

[0053] Figure 3 shows the relationship between the spectral emissivity ratio and the amount of filters collected per unit time. In this figure, circles represent the spectral emissivity ratio (2) / (1), and crosses represent the spectral emissivity ratio (3) / (1). Figure 4 also shows the relationship between the amount of filters collected per unit time estimated from the spectral emissivity ratio (2) / (1) and the actual amount of filters collected per unit time. Here, the equation for the approximate straight line in Figure 3 was used to convert from the spectral emissivity ratio to the amount of filters collected per unit time.

[0054] From Fig. 3, it was confirmed that there is a strong correlation between the spectral emissivity ratio and the filter collection amount. Also, from Fig. 4, it was confirmed that there is a strong correlation between the filter collection amount estimated from the spectral emissivity ratio and the actual filter collection amount. The filter collection amount per unit time correlates with the dust generation rate. Therefore, it was found that according to the present disclosure, it is possible to estimate the dust generation rate with high accuracy.

[0055] [Example 2] The dust generation rate was evaluated using a 300-ton converter, and the converter operation was controlled based on the evaluation. The optical paths used were (1) and (2) above. Here, the same optical system (condenser lens, etc.) was used for all the spectral radiance acquisition units. The spectral radiance acquisition unit also acquired the spectral radiance at the wavelength of interest, 700 nm. The temperature of the combustion flame was estimated using the principle of a two-color pyrometer based on the radiance ratio of wavelengths 700 nm and 900 nm. Then, the spectral emissivity was calculated for each optical path from the ratio of the calculated spectral radiance to the blackbody radiation radiance, and the spectral emissivity ratio (2) / (1) was calculated. The measured dust generation rate (index value) was calculated from the amount of dust collected from the dust collection water.

[0056] Here, the amount of dust collected from the dust collection water is the ratio of the weight of dust contained in the sampled dust collection water to the amount of sampled water when the dust collection water is sampled at a specified interval. Such a dust amount can be obtained, for example, by a filtration analysis that improves on "JIS K 0102 14.1 Suspended solids." Normally, in the above-mentioned "JIS K 0102 14.1 Suspended solids," an appropriate amount is poured into a filter, but since it is not possible to obtain a representative amount for dust with a wide particle size distribution, the collected sample is filtered in its entirety to obtain the dust amount.

[0057] The relationship between the spectral emissivity ratio and the measured dust generation rate (index value) and the elapsed time is shown in Figure 5. Here, at the 2 minute point in Figure 5, the converter operation (lance height and oxygen flow rate) was controlled to reduce the dust generation rate.

[0058] From Figure 5, it was confirmed that the dust generation rate can be reduced by the operator controlling the converter operation while observing the change over time in the spectral emissivity ratio. [Explanation of symbols]

[0059] 1. Smelting furnace 2 Opening 3. Lance 10 Spectral brightness acquisition section 11 Light acquisition section 12 Spectrometer 20 Arithmetic section 100 Dust generation rate evaluation device

Claims

1. An apparatus for estimating the generation rate of dust generated during the operation of a refining furnace, A spectral radiance acquisition unit that includes a combustion flame generated at an opening of the refining furnace, sets a plurality of optical paths having different lengths, and acquires the spectral radiance of a radiation spectrum at a wavelength of interest in each of the optical paths; a combustion flame temperature estimation unit that estimates a temperature of the combustion flame for each optical path when the spectral radiance acquisition unit acquires the spectral radiance; a blackbody radiation luminance calculation unit that calculates a blackbody radiation luminance of the wavelength of interest at the estimated temperature of the combustion flame for each optical path; a spectral emissivity calculation unit that calculates a spectral emissivity for each of the optical paths from a ratio of the spectral radiance acquired by the spectral radiance acquisition unit and the blackbody radiance calculated by the blackbody radiance calculation unit; a spectral emissivity ratio calculation unit that selects two of the calculated spectral emissivities and calculates a spectral emissivity ratio, which is a ratio between the two; a dust generation rate estimation unit that estimates the dust generation rate based on a relational expression between a spectral emissivity ratio and a dust generation rate that has been obtained in advance; A dust generation rate estimation device comprising:

2. The dust generation rate estimation device according to claim 1 , wherein the optical paths include an optical path that includes a lance of the refining furnace on an extension line of the optical path, and an optical path that does not include the lance of the refining furnace on an extension line of the optical path.

3. A refining furnace, the refining furnace being controlled based on a dust generation rate estimated by the dust generation rate estimation device according to claim 1 or 2.

4. A method for estimating the dust generation rate generated in the operation of a smelting furnace, comprising: A spectral radiance acquisition step of setting a plurality of optical paths having different lengths, including a combustion flame generated at an opening of the refining furnace, and acquiring the spectral radiance of the radiation spectrum at a wavelength of interest in each of the optical paths; a combustion flame temperature estimating step of estimating a temperature of the combustion flame for each optical path at the time when the spectral radiance is acquired in the spectral radiance acquiring step; a blackbody radiation luminance calculation step of calculating a blackbody radiation luminance of the wavelength of interest at the estimated temperature of the combustion flame for each optical path; a spectral emissivity calculation step of calculating a spectral emissivity for each of the optical paths from a ratio of the spectral radiance acquired in the spectral radiance acquisition step and the blackbody radiance calculated in the blackbody radiance calculation step; a spectral emissivity ratio calculation step of selecting two of the calculated spectral emissivities and calculating a spectral emissivity ratio, which is a ratio between the two; a dust generation rate estimation step of estimating the dust generation rate based on a relational expression between a spectral emissivity ratio and a dust generation rate that has been obtained in advance; A dust generation rate estimation method comprising:

5. The dust generation rate estimation method according to claim 4, wherein the optical paths include an optical path that includes a lance of the refining furnace on an extension line of the optical path, and an optical path that does not include the lance of the refining furnace on an extension line of the optical path.

6. A method for controlling a refining furnace, comprising controlling the refining furnace on the basis of a dust generation rate estimated by the dust generation rate estimation method according to claim 4 or 5.

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