JPH03503186A - Measurement of blast furnace raceway parameters - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Measurement of Blast Furnace Raceway Parameters The present invention can measure the depth of blast furnace raceways, Concerning the measurement of raceway parameters such as brightness and/or temperature.

The raceway is the space immediately in front of the tuyere of a steelmaking blast furnace. A rotating stream of particles and gas is formed by a hot blast of air exiting the tuyere. . The temperature in the raceway area is typically about 2000<0>C.

Several raceways are evenly distributed around the perimeter of the furnace, and their action generation and distribution of high-temperature reducing gas to the load. Stable furnace operation This temperature reduction is applied to prevent damage to the refractories and maintain a stable load drop. Requires confinement of the gas flow to the center of the furnace.

The depth and shape of the raceways are controlled by the flow of gas and heat in the packed bed of the blast furnace. is a fundamental determinant of flow distribution and therefore has a significant impact on furnace operation and efficiency. make an impact. The potential for general use of raceway depth sensing arises in the furnace combustion zone. It can be expected that improving the basic understanding of the process of Ru. From an operational perspective, raceway depth measurements can contribute in the following areas: can be expected.

Control of uniformity of gas and heat surroundings and - coke quality in the high temperature zone of the furnace. in-situ evaluation of the effects of change; Control of a-temperature metallic silicon by optimizing the position of the single coagulation zone; - Optimization of casting performance through internal sensing of internal liquid level.

Regarding the second of these areas, the raceway depth is is a function of coke average size and therefore gives a good indication of coke quality in the high temperature zone. It was theoretically shown that This relationship applies to both the high temperature model and the operating furnace. , but the results obtained when measurements are carried out in several blast furnaces There is significant disagreement over the exact form of the correlation and significant scattering between That is clear. Differences in raceway depth measurements contribute to this confusion. In particular, the confusion in considering the raceway effects of the intrusive measurements being used It seems to contribute.

Traditional measurement of raceway depth involves introducing a water-cooled metal probe through the depended on. For these measurements, the raceway walls are observed to have a given wall pressure. or when the probe stops moving. single Measurements can be performed in less than a minute, but repeated measurements can be difficult and dangerous. It is. This technique also has several other drawbacks.

That is, (2) It is invasive, capable of interfering with raceway dynamics, and This causes a change in the exact parameter to be measured.

(c) Deflection of the probe within the raceway introduces uncertainty into the measurement.

(c) Repeated measurements in the conventional regime are impractical. After each measurement, the probe be withdrawn into the blowpipe or allowed to cool before other measurements can be performed. must be completely removed.

(f) The technique cannot be used to make composite depth measurements of some raceways. be. Completely separate measuring equipment must be used for each raceway .

Recently, additional parameters such as raceway depth and condensation zone location and hearth discharge parameters have been Theoretical predictions of the relationships between operational variables were made. The model settings significantly improve understanding. However, if this benefit is to be secured, We believe that raceway depth measurement techniques must be developed that are adaptable to the operating mode. be exposed. This is therefore an object of the present invention.

The present invention essentially demonstrates that optical techniques can be successfully used for raceway depth measurements. recognition that the technique can meaningfully measure other raceway parameters. and the unexpected discovery that it can be used. The first appearance consideration is that the optical technique is similar to that of a blast furnace. - In a poor sway environment, especially coke particles moving at relatively high velocities. Given the continuous existence of the group, this suggests that it will not succeed.

Therefore, the present invention provides a method for analyzing raceways in a blast furnace floor, which method transmit optical signals into the raceway and reflect the transmitted optical signals within the raceway. or monitor the received signal obtained by scattering and measure the parameters of the raceway. It includes a procedure for analyzing the received signal with respect to the transmitted signal to obtain the accuracy.

The invention inter alia provides a method for measuring raceways in a blast furnace floor, the method comprising: An optical signal, preferably a laser beam, is directed along the blowing tube, thereby causing the associated Sent into the raceway through the opening and reflected by the floor interface that confines the raceway monitor the received signal with at least a portion of the signal reflected, and determine the location of the reflecting interface. It has a procedure for analyzing the received signal with respect to the transmitted signal as specified.

Analysis of the received signal preferably includes the initial transmission of the signal and an identifiable portion of the received signal. Includes a time-of-flight analysis that depends on the time that has elapsed between reception. This received signal is Preferably, it is a part of said reflected signal that is returned along the blowpipe. during flight An alternative to interval analysis is the delta analysis method.

Further, the present invention provides a blast furnace having a blowing pipe opening penetrating the furnace wall. An apparatus is provided for analyzing a raceway adjacent to an inlet pipe opening in a floor, the apparatus comprising: , a sit positioned relative to the blast furnace to transmit an optical signal into the raceway; Reception resulting from reflection or scattering of a transmitted optical signal on the raceway A device that monitors the transmission signal and analyzes the reception signal against the transmission signal and performs a race. and a device for obtaining a measure of the parameter of the way.

The signal transmitting device and the signal analyzing device are configured such that at least a portion of the transmitted optical signal is - is reflected by the floor interface that limits the sway, which causes the analysis to It may be arranged to obtain a measure of position.

The device is preferably arranged in an insufflation tube through which the transmitted and received signals pass. A suitable window assembly is provided.

Most advantageously, the transmitted optical signal is a series of pulses and the received signal is another - A series of pulses, where the reflections or reflections resulting from each transmitted pulse can be identified , whereby the depth of the raceway arises from the farthest point of the raceway. It can be measured by the reflected pulse that is observed to be Preferably, the multiplex transmission The main return reflections of the signals are detected and the frequency of reflections is indicated by the received reflections. raceway depth is compared for different distances. When the frequency is greater than the frequency for the immediate distance, it is determined from the farthest distance. , the transmitted pulses preferably have a size similar to the average size of the coke particles in the raceway, e.g. The beam is also constructed in such a way that it facilitates the conclusion of the farthest distance by means of a ray of fairly small cross-section. Ru.

The invention will now be further described, by way of example only, with reference to the accompanying drawings, in which: FIG. 1 shows a racewear according to the invention shown in operative connection with a blowing pipe of a blast furnace; Figure 2 is a schematic diagram of Measurement II, which shows the depth of the raceway in a particular blast furnace. The three successively detected returns obtained when using the apparatus of Figure 1 to measure Figures 3A and 3B show transmission beam interruptions of 1:8 and 1:1, respectively. Detection of different distances indicated by reflection to surface/coke particle size ratio is a bar graph of the frequency of reflections, FIG. 4 shows the selected detection results over an extended period of time when using the device of FIG. Figure 5 shows the predetermined signals for each of the ray cross sections of 6jw and 60m. the minimum distance, i.e. the distance indicated by the earliest reflection, over a period of It is a cut.

The apparatus shown in FIG. 1 has a fireproof wall 11 and is equipped with a blowing pipe 12! Equipped with 4 blast furnaces 10 ing. The insufflation tube 12 is a conduit that blows oxygen and other gases into the cough floor 14. It penetrates the furnace wall 11 and opens into the water-cooled tuyere 16 . Raceway 18 is a tuyere A blow tube 12 is formed in the floor adjacent to the raceway for the purpose described above. A device 20 for measuring the way, in particular its depth, is attached.

Attire! 20 is i! on the bend of the blow pipe. to measure the depth of the raceway It has a sealed 1 ft silica solid 22 that forms the proximity port of the light to be utilized. are doing.

The light source or transmitter includes a nitrogen laser 24 with an operating wavelength of 337.1 n-. The laser beam is directed concentrically along the blow tube by 1126. It will be done. The portion of the light reflected at the interface 19 that bounds the raceway is a narrow band It is focused by lens 28 via filter 29 to the detector/preamplifier. Fi The router 29 filters copper background radiation outside the laser emission wavelength from the detector field of view. It is a 1onI bandpass filter centered at 337.1r++s. received optics The preamplifier output of the direct electrical representation of the signal is polarized by beam splitter 34. The start pulse detector 36 can also respond to a portion of the transmitted signal directed to the to a suitable analyzer and/or display device 132. Analyzer/display Attire! i32, the depth of raceway 18 is determined by time-of-flight analysis. Similarly, it gives an indication of the time delay between the transmitted and received signals.

Analyzer 32 is preferably an analog processor. beginning and return The pulse is a 20 μs voltage whose amplitude is proportional to the time of flight of the laser pulse. Using constant division identification and time-to-pulse height conversion to generate pulses Processed by the processor.

For each laser pulse transmitted, the amplitude of the voltage pulse changes rapidly A/D! I The target distance obtained using the IB and measured from the edge of the cuff (i.e., relative to the reflection) distance), which is then stored. Each distance measurement Timestamped to allow subsequent correlation with furnace parameters.

The nitrogen laser mentioned above is a preferred source in view of several considerations. Inside the raceway The main requirement for the time of flight over is a suitably short pulse length, which The length of the raceway is determined by The coke particles have a reasonable chance of decomposing the radiation reflected by the coke particles. must be shorter than or comparable to the separation of particles. 1n A pulse length shorter than s (equal to a 300 lm long pulse of light) is approximately 150 lm long It would be possible and preferred to resolve targets separated by m+. cough short pulses , is best obtained from a laser source, and the use of a laser also necessary to provide the required field of view limited by and typically less than 30m+ Align with spatial criteria.

Besides its ability to produce short pulses, the other main consideration when selecting a source is its wavelength. It is. The rear wall of the raceway is a non- It is always a bright source and therefore some degree of spectral discrimination is necessary. Leh The blackbody's svec1~le brightness at a temperature near the sway temperature (approximately 2000") The brightness is highest in the visible for the very near infrared. various lasers emission wavelength and short pulse length requirements and long-lived lasers based on well-established technology. When considering the desirability of using a nitrogen laser, a nitrogen laser appears as the preferred choice. It becomes clear. A typical nitrogen laser has a pulse length of 0.3 ns and a It is also characterized by a pulse power of - and a repetition rate of 20 Hz.

Figure 2 shows the continuous process carried out in a blast furnace operated by a single incident laser pulse. A simple output signal for measurements is shown. The peak on the left is at the T degree feather ronose. This is due to coke, and the peak on the right is due to the interface after the raceway. The apparent raceway depth on a time-of-flight basis is assumed to be approximately 0. ．． 8 m, which corresponds to the expected value for this furnace.

Recognized as being reflected from the deepest point of the raceway for a series of transmitted pulses The pulses are identifiable and define the raceway, i.e., the raceway depth. It is recognized that it is desirable to be able to identify each reflection of a pulse. Commercially available distance A remote measurement device typically uses a series of reflected pulses to minimize the effects of noise. It is not applicable to raceway depth measurements because it averages results over this Averaging eliminates the information given by each individual reflected pulse and It is the information present in each individual reflected pulse in the case that indicates the depth.

Identify and ignore reflections from coke pieces at the exact line of sight in front of the raceway wall. , perform multiple measurements to establish that the final reflection was positively returned from the raceway wall. It is preferable to apply One method is to use distances measured over short time intervals. (i.e. some return reflected pulses are give a distance value within each short set of values), then the right-hand limit of the plot The peak of confirms that this farthest distance is probably just the raceway wall. Ru. The frequency of reflections at the farthest measured distance is directly equal to the frequency at closer distances. If the value is not large, then the right-hand limit of the bar graph plot is a coke particle. The possibility cannot be completely ignored. Figure 3B illustrates this case and shows similar rays The cross-section is made for the particle size, and the ray cross-section is determined by comparison with Figure 3A. must be significantly smaller than the average size of the coke particles in the raceway. It suggests that something is wrong. The distance also becomes critical when going from 10 pulses to 50 pulses. It was found that there was a significant leveling out when going from 50 pulses to 100 pulses. , 100 pulses, perhaps only <50 pulses to 100 pulses move rapidly For eliminating rapid distance fluctuations caused by laser beams scattered by coke particles Suggests that it is sufficient. A crucible of more than 100 pulses has a very large number of additional information, or in some cases, the desired smoothing of raceway depth variations. Ru.

Instead, in order to satisfactorily decompose the raceway interface from the circulating coke, The detector/premultiplier 32 must have a bandwidth on the order of 700 MHz. stomach.

Figure 4 is representative of the return data produced for multiple pulses over a specified period of time. This shows the group. These curves can be used to define other raceway parameters. It turned out that it can be used. In Figure 4, the top curve is the maximum distance encountered (already ), the second curve is the minimum distance, and the third and fourth curves are red, respectively. and the brightness of blue, and the fifth is effectively the raceway temperature, and the lowest is This is the amount of air blown. Raceway depth plots last from tens of seconds to tens of minutes In this case, the depth is reduced to a value less than half of the average value of the period. Ru. Analysis of the video images transported at the same time showed that these objects were falling onto the raceway area. Resulting from a piece of bandage or skull, the raw material is gradually blown away by the blast of air. This shows that the depth is restored. Some of these events are programmed as a function of time. It is believed that the incidence of these events is a measure of the proximity of the coagulation zone. It will be done.

Generally assumes that the posterior wall does not move significantly over the time scale of a single depth measurement The frequency of pulse penetration into the wall then increases as the ratio of the ray to the particle size decreases. increases to To test this, a simple two-dimensional model of the raceway was set up. The effect of varying laser beam dimensions on laser return statistics was investigated. Ta. The model uses laser beam dimensions that are large and small compared to the average coke size. The radar is determined by comparing the statistical distribution of returns with alternating depth measurements made. It was also used to investigate the possibility of sizing coke within the sway region.

The model is a two-dimensional model in which a random distribution of identical spherical coke particles is generated. Consists of space. Made with raceway high speed film (5000 frames/sec) The velocity measurements carried out are based on coke particle traverse speeds ranging from 0.5 m/s to 12 m/s. It was shown that it was within the range. Depth of 1,277L, the maximum depth previously measured For a raceway, the maximum transit time through the raceway is approximately 8 nanoseconds. Ru. This is equivalent to a coke motion of 0.1 microns. Therefore, the raceway The coke particles are almost frozen during a single pulse measurement.

It is considered that a specific blast volume distribution occurs when the blast leaves the tuyere and enters the raceway. available. This allows small particles to fill the raceway before they reach the centerline of the tuyere. while larger particles move farther into the raceway before vertical This causes the air to penetrate. This means that if the laser beam is large, the cough beam will be It hits both large and small coke very close to the tuyere nose and is sensitive to the small laser beam. so that the smaller coke hits later in the raceway than the larger coke. means. In practice, for small diameter laser beams, coke is encountered The minimum distance is a measure of coke size after considering other factors such as air flow, etc. may be interpreted as such. Figure 5 shows a) the cross-sectional dimensions of the light beam for 60 shoes, and b) the light beam for 6 m. Comparison of minimum coke distance for 38P PBPD using line cross-sectional dimensions show. The difference in distance is a function of the coke trajectory mentioned above and hence the relative average coke size. attributed to scale.

Occasionally short distances for small ray dimensions result in occasional large rays entering the raceway. It is recognized that this shows the possibility of solid coke pieces. When the flow rate of air volume is considered, The system provides real-time continuous measurement of coke dimensions in the raceway. expected to occur.

Although FIG. 1 only shows a measuring unit mounted on a single blowpipe, in practice source laser, detector/preamplifier, analyzer/display device, and associated It is possible to combine a single measuring unit with optical elements for several tuyeres. ,preferable. This is most preferably accomplished via a fiber optic network. costs and Apart from the savings in efficiency and efficiency, there are also benefits to moving instruments out of the direct environment of the blast furnace. exist.

The raceway depth measurement device described above is successfully non-invasive and approximately ±5ON1 of 5TrL with an accuracy of at least 1 usable measurement per minute. It is possible to operate over typical distances, including distances of 1. single raceway depth The length of time to perform the measurement is approximately 10 minutes using a pulse repetition frequency of 1QH7. Seconds. The device can handle a narrow field of view of less than 30 m, and can handle high pressure and It is capable of operating in environments involving gas blowing at high speeds and temperatures. The device The flame from the combustion of the injection fuel and the back temperature of approximately 2500℃ provided by the coke target. Built in a raceway with a significant amount of circulating coke relative to the ambient temperature. Available for use.

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Claims (10)

[Claims] 1. A blowing pipe opening in the floor of a blast furnace having a blowing pipe opening passing through the furnace wall. In the raceway analysis equipment adjacent to the. Optical signals within the raceway a device positioned relative to said blast furnace to transmit information to said blast furnace; Transport at the raceway A device for monitoring a received signal obtained by reflection or scattering of the transmitted optical signal. and. Analyze the received signal with respect to the transmitted signal and thereby determine the speed of the raceway. and a device for obtaining a measure of a parameter. 2. The apparatus according to claim 1, wherein at least one of the optical signals transmitted is A portion of both is reflected by the floor interface that limits the raceway, thereby causing the said signal transmitter and said analyzer, such that the analyzer obtains a measure of the position of said reflecting interface. The device where the device is located. 3. For the apparatus according to claim 1 or 2. the transmitted signal and The apparatus further comprises a window assembly in the blowpipe through which a received signal passes. Place. 4. In the apparatus according to any one of claims 1 to 3, The transmitted optical signal is a series of pulses, and the received signal is a series of pulses. It's Luz. The or each reflection caused by the transmitted pulse is identifiable. can be. This causes the depth of the raceway to vary from the farthest point of the raceway. A device that can be measured by the reflected pulses observed as they occur. 5. The device according to claim 4, wherein the analyzing device is configured to analyze received reflections. Therefore, it is determined to compare the frequency of reflection for different distances indicated, and the farthest distance is When the frequency of distance reflections is greater than the frequency for immediate distances, the device in which the ray depth is determined by the farthest distance. 6. In a method for analyzing raceways on the floor of a blast furnace, Send an optical signal. reflection of the transmitted optical signal towards the raceway or Monitor the received signal obtained by scattering and measure the parameters of the raceway. A method comprising: analyzing the received signal relative to the transmitted signal to obtain a signal. 7. 7. The method of claim 6, wherein the transmitted optical signal is reflected by the floor interface that bounds the raceway, which makes the above analysis A method for obtaining a measure of the position of the interface. 8. The method according to claim 6 or 7, wherein the transmitted and received A signal is sent to the blowing officer associated with said raceway and from said blowing pipe to the window sail. How to pass through solid objects. 9. The method according to any one of claims 6 to 8, The optical signal transmitted is a series of pulses. When the received signal is It's Luz. The or each reflection caused by the transmitted pulse is identifiable. This causes the depth of the raceway to increase from the farthest point of the raceway. A method that can be measured by reflected pulses that are seen as 10. 9. The method according to claim 9, wherein the frequency of the reflections is greater than the received reflections. Therefore, the reflection frequency at the farthest distance is compared for the different distances shown, and the reflection frequency at the farthest distance is When the raceway depth is greater than that of the farthest distance, method determined.