JP2015052148A - Method for controlling blast furnace by determining operational situation thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for controlling a blast furnace by determining the operational situation of the blast furnace, in which method each of tuyeres of the blast furnace and a furnace interior situation or a facility situation in the furnace circumferential direction are detected/determined accurately and quickly in order to change operational conditions accurately and quickly.SOLUTION: An operation determination method comprises the steps of: imaging combustion states in a raceway with time by using an image pickup device disposed at an observation hole of the tuyere of the blast furnace; and determining the furnace interior situation or the facility situation according to the picked-up images. The method for controlling the blast furnace by determining the operational situation of the blast furnace comprises: a step (i) of expressing the furnace interior situation or the facility situation by an exponential function according to the luminance of the picked-up image and determining the furnace interior situation or the facility situation according to an index of the exponential function or a temporal change of the index; a step (ii) of expressing the furnace interior situation or the facility situation by the exponential function according to the luminance of the picked-up image, calculating an exponential distribution in the furnace circumferential direction and determining the furnace interior situation or the facility situation according to the calculated exponential distribution or the temporal change of the distribution; and a step (iii) of changing the operational conditions according to the determined result.

Description

  The present invention indexes the situation inside the furnace or the equipment situation based on the brightness of the image taken by the imaging device installed in the observation hole of the tuyere, and the operation situation in the tuyere and the furnace circumferential direction based on the index. The present invention relates to a method for determining and controlling blast furnace operation based on a determination result.

  In blast furnace operation, hot metal, oxygen, pulverized coal (fuel), etc. are blown from a tuyere arranged at equal intervals in the furnace circumferential direction in the lower part of the furnace to produce hot metal. At the back of the tuyere, a raceway is formed by the blowing pressure, and the blast furnace raw material (mainly sintered ore) is reduced here.

  In order to increase the productivity of the blast furnace, pulverized coal is usually blown from the tuyere, but the combustion state of the pulverized coal at the back of the raceway greatly affects the in-furnace condition (furnace condition). When the combustion state of pulverized coal deteriorates, the amount of heat necessary for the reduction of the blast furnace raw material cannot be obtained sufficiently, and the situation inside the furnace deteriorates.

  Therefore, in order to determine the in-furnace situation, various technologies have been proposed to provide an imaging device in the observation hole of the tuyere and monitor the combustion state of pulverized coal at the back of the raceway and to measure the temperature in the raceway Has been.

  Patent Document 1 proposes a method in which a radiation temperature camera is installed in the tuyere, the temperature distribution in the tuyere obtained by the radiation temperature camera is continuously stored by image processing, and the temperature distribution in the tuyere is evaluated. Yes.

  In Patent Document 2, a radiation temperature camera is installed in the tuyere peephole, the brightness of the set point of the tuyere's visual field is measured in a non-contact manner, the brightness is converted into temperature by an image analyzer, and the temperature setting period is set. A method of calculating the raceway decay period and evaluating the raceway state based on the spectrum analysis of the average time series data has been proposed.

  In Patent Document 3, when the coke temperature in a raceway is optically measured through an observation hole provided behind a tuyere, radiation light obtained from the observation hole is converted into a television camera having a high-speed shutter and a radiation temperature. A method for measuring the coke temperature in the raceway is proposed in which the coke temperature is calculated based on the image signal of the television camera and the temperature signal of the radiation thermometer.

  However, in any of the methods, the accuracy of the image is insufficient, and it is difficult to distinguish and discriminate the in-furnace situation, for example, the expansion of pulverized coal or the loss of raw mines, with one image. In order to accurately detect the in-furnace situation, continuous image processing is required.

  Based on this, in Patent Document 4, through the observation hole of the tuyere, an imaging device that captures a thermal image of the combustion field in the raceway at two different wavelengths, and an image signal of each wavelength that is output by the imaging device. We proposed a blast furnace tuyere raceway temperature distribution measuring device equipped with a digital conversion device that converts to a digital image and a small computer that calculates the temperature distribution based on the luminance ratio of the digital image of each wavelength.

  According to the apparatus disclosed in Patent Document 4, since the electronic shutter exposure time of the imaging apparatus is automatically controlled so that the image brightness becomes appropriate brightness, the transmittance of the observation hole is reduced due to dirt or fogging of the glass. Because it is difficult to be affected, it is possible to calculate an accurate temperature distribution and detect changes in furnace conditions quickly and accurately, but the automatic control of the electronic shutter exposure time for each imaging device is different because the setting of the imaging device is different. In the case of processing, it becomes difficult to quantitatively evaluate the result of image processing in the circumferential direction.

  In view of this, the present applicant can place a thermal radiance image in a thermal radiance image obtained by fixing the electronic shutter exposure time of the imaging device to an appropriate setting with an imaging device provided in the blast furnace tuyere in Patent Document 5. Generate a normalized image by performing geometric transformation so that the outline shape of the tuyere becomes a normalized circle, convert the normalized image to polar coordinates, then binarize to generate a binarized image, and binary We proposed a method and apparatus for observing the in-furnace state using the radial distribution of the normalization circle of the bright part existing in the normalized image.

  The observation method and apparatus proposed in Patent Document 5 pay attention to raw ore falling where unmelted ore falls and pulverized coal expansion where the image of unburned pulverized coal expands rapidly. It functions effectively for observation.

JP 05-256705 A JP 07-305105 A JP 09-256010 A JP 2001-318002 A Japanese Patent Application No. 2012-053012

  Although the observation method and apparatus proposed in Patent Document 5 function effectively for observation of raw mine dropping and pulverized coal expansion, the state that hinders blast furnace operation is raw mine dropping and pulverized coal expansion (pulverized coal injection shape). Not limited to.

  In addition, pulverized coal blowing lances (clogging and vibration of the lance, foreign matter adhering to the tip of the lance), coke and pulverized coal flowing back from the tuyere (feather backflow), There are a state in which the tuyere is closed (tuyere closed), a state in which pig iron and slag accumulated in the furnace rises to the tuyere level, and the tuyere may be melted (noro spring).

  The present invention accurately and quickly detects the occurrence of the above-mentioned state, accurately and quickly determines the state of the furnace or the state of equipment in the blast furnace individual tuyere and the circumferential direction of the furnace, and based on the determination result, It is an object of the present invention to provide a control method that solves the problem by changing the operation conditions accompanying the generation accurately and promptly and controlling the blast furnace operation appropriately.

  The present inventors diligently studied a control method for solving the above-described problems. About the omission of mine and expansion of pulverized coal, the observation method proposed by the present applicant in Patent Document 5 can be accurately detected. The present inventors examined a method for accurately and quickly detecting the state of the pulverized coal blowing lance, the tuyere backflow, the tuyere blockage, and the occurrence of the noro spring.

  As a result, it was found that the images of the combustion state in the raceway were indexed, and the occurrence of tuyere backflow, tuyere occlusion, noro-spring, and lance abnormality could be detected accurately and quickly. This detection method will be described later.

  This invention was made | formed based on the said knowledge, and the summary is as follows.

(1) With an imaging device arranged in the observation hole of the tuyere of the blast furnace, the combustion state in the raceway is imaged over time, the in-furnace situation or equipment situation is determined based on the captured image, and based on the determination result In a method for controlling blast furnace operation,
(I) Indexing the in-furnace situation or equipment situation based on the brightness of the captured image, and determining the in-furnace situation or equipment situation based on the index or the change over time of the index;
(Ii) By indexing the in-furnace situation or equipment situation based on the brightness of the captured image, obtaining the exponential distribution in the furnace circumferential direction, and determining the in-furnace situation or equipment situation based on the distribution or the change over time of the distribution And
(Iii) A control method based on operation status determination of a blast furnace, wherein the operation conditions are changed based on a determination result.

  (2) The control method based on the operation status determination of the blast furnace according to (1), wherein the in-furnace situation is a raw ore dropping.

  (3) The control method based on the operation status determination of the blast furnace according to (1), wherein the in-furnace situation is a pulverized coal injection shape.

  (4) The control method based on the operation status determination of the blast furnace according to (1), wherein the facility status is a status of a pulverized coal injection lance.

  (5) The control based on the operation status determination of the blast furnace according to (1), wherein the facility status is a status in which coke or pulverized coal flows backward from the tuyere or a status in which the tuyere is blocked. Method.

  (6) The control method based on the operation status determination of the blast furnace as described in (1) above, wherein the facility status is a noro spring.

  (7) The control based on the operation status determination of the blast furnace according to any one of (1) to (6), wherein the operation condition is one or both of a pulverized coal injection amount and a hot air blowing amount. Method.

  According to the present invention, a change in the in-furnace situation or facility situation in the furnace circumferential direction of the blast furnace is accurately and quickly detected and determined, and based on the determination result, the change in the operation condition associated with the change is accurately and promptly determined. Since it can be performed, blast furnace operation can be controlled accurately.

It is a figure which shows the change of the in-furnace condition in a blast furnace operation, and the change of the operation condition with respect to it. It is a figure which shows one embodiment of this invention. It is a figure which shows the R component image produced by extracting the R component of a brightness | luminance from the captured still image (RGB image). It is a figure which shows the image processing procedure which indexizes the brightness | luminance of R component image and detects a tuyere backflow or tuyere obstruction | occlusion. It is a figure which shows the R component image produced by extracting R component from the still image (RGB image) which imaged the combustion state in a raceway at intervals of 0.5 second.

  The present invention will be described below with reference to the drawings.

  In FIG. 1, the change of the in-furnace condition in a blast furnace operation and the change of the operation condition with respect to it are shown. For example, if a raw ore drop occurs and the brightness of the raceway image taken through the observation hole in the tuyere decreases, the furnace heat decreases, and the effect is naturally a change in the shape of the cohesive zone. (See FIG. 1). On the other hand, when the brightness of the image of the raceway taken through the observation hole of the tuyere increases, the furnace heat has risen, and the influence is naturally manifested in a change in the shape of the cohesive zone (see FIG. 1). ).

  Changes in the shape of the cohesive zone induce turbulence in gas flow, fluctuations in air permeability, and fluctuations in the heat load in the furnace, and these disturbances and fluctuations induce changes in the shape of the cohesive zone. Therefore, blast furnace operation is not stable.

  Conventionally, as shown by X in FIG. 1, for example, after confirming a change in a reduction index that can be obtained conventionally, such as hot metal temperature at the time of tapping, the operation conditions (the amount of pulverized coal injection, the amount of hot air blowing, etc.) Had changed. However, it was several hours after changing the operating conditions that the operation index such as the hot metal temperature could be confirmed, and it took time until the confirmation after changing the operating conditions.

  During this time, the shape of the cohesive zone changes in response to disturbances in gas flow, fluctuations in air permeability, and fluctuations in the heat load in the furnace. It may not function effectively for stabilization. Occasionally, changes in operating conditions to stabilize the gas flow and breathability in the furnace and the shape of the cohesive zone were delayed, leading to instability of the shape of the cohesive zone. The situation can fall into a vicious circle.

  Therefore, in order to properly control blast furnace operation, it is necessary to accurately detect changes in the furnace conditions and changes in equipment conditions, and to change operating conditions based on these changes accurately and quickly. is there.

  Therefore, the control method based on the operation status determination of the blast furnace according to the present invention (hereinafter also referred to as “the present control method”) is based on an image obtained by imaging the combustion state of the raceway, Alternatively, the basic idea is to accurately and promptly determine the equipment status and to change the operating conditions based on the result of the determination based on the change in the furnace status or the equipment status accurately and promptly.

Specifically, the control method of the present invention is an imaging device arranged in the observation hole of the tuyere of the blast furnace, which captures the combustion state in the raceway over time, and based on the captured image, the in-furnace situation or the equipment situation In a method for determining and controlling blast furnace operation based on the determination result,
(I) Indexing the in-furnace situation or equipment situation based on the brightness of the captured image, and determining the in-furnace situation or equipment situation based on the index or the change over time of the index;
(Ii) By indexing the in-furnace situation or equipment situation based on the brightness of the captured image, obtaining the exponential distribution in the furnace circumferential direction, and determining the in-furnace situation or equipment situation based on the distribution or the change over time of the distribution And
(Iii) The operation condition is changed based on the determination result.

  FIG. 2 shows an embodiment of the control method of the present invention.

  A hot air 9 is blown into the furnace at a high pressure from a hot air supply pipe 6 inserted into a tuyere 4 provided in the blast furnace furnace body 3 to form a raceway 1. The hot air supply pipe 6 is provided with a pulverized coal blowing pipe 5 for blowing pulverized coal 8 into the raceway 1. In FIG. 2, two pulverized coal blowing pipes are arranged, but one arrangement may be used.

  In the raceway 1, coke and pulverized coal are combusted, and a high temperature combustion reaction is generated in which carbon monoxide is generated. An imaging device 10 that images the combustion state in the raceway 1 is disposed in the observation hole 7 of the hot air supply pipe 6.

  The imaging device 10 is controlled by the imaging control device 11 and images the combustion state in the raceway 1 3 to 4 m away from the imaging device through an observation hole having a diameter of about 20 mm. The captured image is displayed on the image display device 12, and a required indexing process is performed on the image processing device 13, and the indexed image information is basic information for determining the in-furnace situation or the equipment situation. Is transmitted to the operation status determination device 14.

  The operation status determination device 14 determines the in-furnace status or facility status based on the basic information, and the determination result is transmitted to the operation control device 15 so that the change of the operation conditions is performed quickly and the blast furnace operation is properly performed. Controlled.

  Here, FIG. 3 shows an R component image created by extracting an R (red) component of luminance with an image processing device from a still image (RGB image) obtained by imaging a combustion state in a raceway with a color CCD camera. Show. Among the RGB signals of the color CCD camera, it has been confirmed in advance that the luminance of the R component and the luminance of the G (green) component have a correlation with temperature, and here, an R component image is shown. The image is an image when two pulverized coal blowing lances are inserted into the hot air supply pipe.

  Next, in order to change the operating conditions accurately and quickly, an image processing procedure for indexing the luminance of the R component image and detecting changes in the furnace condition or the facility condition accurately and quickly will be described.

  Ore dropping and pulverized coal expansion (pulverized coal injection shape) can be accurately detected by the observation method proposed by the present applicant in Patent Document 5.

  For example, in the case of pulverized coal expansion (pulverized coal injection shape), if the furnace condition is good, the shape is such that pulverized coal is sucked into the furnace, but the air permeability decreases and the furnace condition deteriorates. In this case, the pulverized coal has an expanded shape that fills the captured image.

  Then, based on the luminance of the image (R component image or G component image) picked up over time, the raw mineral drop or the pulverized coal injection shape is indexed to obtain the index distribution in the furnace circumferential direction, and the index Based on the temporal change of the distribution, the in-furnace situation in the furnace circumferential direction can be determined three-dimensionally.

  FIG. 4 shows an image processing procedure for indexing the luminance of the captured image and detecting tuyere backflow or tuyere blockage.

  In the R component image, the maximum luminance and the minimum luminance of the processing region are acquired, and then the luminance of the image is determined. When the brightness of the captured image does not exceed a certain level (in the case of “NO (1)” in the figure), an alarm is output for quick change of the operating conditions.

  On the other hand, if the brightness of the captured image is above a certain level (“YES (1)” in the figure), a threshold value for binarizing the image is calculated, and binarization is performed based on this threshold value. The area ratio of the bright part at is calculated.

  If this area ratio is less than the reference value (in the case of “NO (2)” in the figure), the time for which the less than the reference value continues is determined, and if the duration is less than the reference value (“NO (3 in the figure) In the case of “)”), if the duration is not less than the reference value (“YES (3)” in the figure), an alarm is output for quick change of the operating conditions.

  If the image processing procedure shown in FIG. 4 is performed at predetermined time intervals, it is possible to three-dimensionally determine temporal changes in tuyere backflow and tuyere occlusion. In addition, the state of the pulverized coal injection lance, the state of the furnace and the equipment state with the noro spring should be detected over time by the image processing procedure using the brightness of the captured image as in the image processing procedure shown in FIG. Can do.

  As described above, with the imaging device arranged in the observation hole of the tuyeres of the blast furnace, based on the brightness of the captured image obtained by imaging the combustion state in the raceway over time, the blast furnace operation is inhibited, In-furnace conditions such as pulverized coal expansion (pulverized coal injection shape), tuyere backflow, tuyere clogging, noro springs, and pulverized coal injection lance abnormality (equipment status) can be indexed and detected. And based on the time-dependent change of the exponential distribution in the furnace circumferential direction, it is possible to determine the in-furnace situation or the equipment situation in the furnace circumferential direction, and further control the blast furnace operation by changing the operation condition based on the determination result. be able to.

  As the operating conditions that can be changed, one or both of the pulverized coal blowing amount and the hot air blowing amount are preferable. Both are operational conditions that can be changed immediately and can immediately improve the in-furnace situation or equipment situation in the furnace circumferential direction.

  Next, examples of the present invention will be described. The conditions in the examples are one example of conditions used for confirming the feasibility and effects of the present invention, and the present invention is based on this one example of conditions. It is not limited. The present invention can adopt various conditions as long as the object of the present invention is achieved without departing from the gist of the present invention.

Example 1
With the imaging device shown in FIG. 2, an RGB image obtained by imaging the combustion state in the raceway at intervals of 0.5 seconds was obtained. An R component image was created by extracting the R component from the RGB image. FIG. 5 shows an example of the created R component image. The luminance of the R component image was indexed, and the index distribution in the furnace circumferential direction was observed over time.

  As a result, it was found from the image after 3.0 seconds that a drop in raw mineral had occurred. Immediately, an abnormality was determined by the operation status determination device, and the operation control device changed the operation condition (heat increase). Action).

  As described above, according to the present invention, it is possible to accurately and promptly detect and determine a change in the in-furnace situation or equipment situation in the circumferential direction of the blast furnace, and based on the determination result, change in operating conditions accompanying the change. Can be performed accurately and quickly, so that blast furnace operation can be controlled accurately. Therefore, the present invention has high applicability in the steel industry.

DESCRIPTION OF SYMBOLS 1 Raceway 2 Filling in a furnace 3 Blast furnace furnace body 4 Tuyere 5 Pulverized coal injection pipe 6 Hot air supply pipe 7 Observation hole 8 Pulverized coal 9 Hot air 10 Imaging device 11 Imaging control device 12 Image display device 13 Image processing device 14 Operation Situation judgment device 15 Operation control device

Claims (7)

With the imaging device placed in the observation hole of the tuyere of the blast furnace, the combustion state in the raceway is imaged over time, the in-furnace situation or equipment situation is judged based on the captured image, and the blast furnace operation is performed based on the judgment result In the method of controlling
(I) Indexing the in-furnace situation or equipment situation based on the brightness of the captured image, and determining the in-furnace situation or equipment situation based on the index or the change over time of the index;
(Ii) By indexing the in-furnace situation or equipment situation based on the brightness of the captured image, obtaining the exponential distribution in the furnace circumferential direction, and determining the in-furnace situation or equipment situation based on the distribution or the change over time of the distribution And
(Iii) A control method based on operation status determination of a blast furnace, wherein the operation conditions are changed based on a determination result.   The control method based on operation status determination of a blast furnace according to claim 1, wherein the in-furnace situation is a drop of raw ore.   The control method based on operation status determination of a blast furnace according to claim 1, wherein the in-furnace situation is a pulverized coal injection shape.   The control method based on operation status determination of a blast furnace according to claim 1, wherein the facility status is a status of a pulverized coal injection lance.   2. The control method based on the operation status determination of the blast furnace according to claim 1, wherein the equipment status is a status in which coke or pulverized coal flows backward from the tuyere, or a status in which the tuyere is closed.   The control method based on the operation status determination of the blast furnace according to claim 1, wherein the facility status is normal spring.   The control method based on the operation status determination of the blast furnace according to any one of claims 1 to 6, wherein the operation condition is one or both of a pulverized coal injection amount and a hot air blowing amount.