JP6631588B2 - Method for detecting deviation of charge descending speed and method for operating blast furnace - Google Patents

Description

  The present invention provides a method for detecting a deviation in the charge descending speed for detecting the circumferential deviation of the descending speed of the charge in the blast furnace, and corrects the deviation when the circumferential deviation is detected. It relates to a blast furnace operating method.

  In blast furnace operation, the descent of coke and ore raw materials is controlled. By feeding a certain amount of hot air from the lower part of the blast furnace, the raw material charged from the upper part of the furnace stably descends from the upper part of the furnace. While the raw material descends in the blast furnace, the raw material goes through steps such as heating, reduction, and melting step by step, so that the entire thermal balance in the blast furnace is maintained.

  In the blast furnace, hot air rises from the lower part of the furnace through the gap between the deposited raw materials. When the gap between the deposited materials is large, a large amount of hot air rises, and when the gap is small, relatively little hot air rises. In a blast furnace, usually, a large amount of coke having a large particle diameter is charged on the central axis side of the furnace, and a large amount of ore having a small particle diameter is charged on the furnace wall side. A gas flow is formed. Then, in order to maintain the productivity of the blast furnace at a high level, the amount of hot air blown is increased to burn more coke, thereby promoting the temperature rise, reduction, and melting of the ore.

  However, if the balance of the coke consumption in the circumferential direction is lost, the lowering speed of the raw material is not uniform in the circumferential direction, and a circumferential deviation occurs in the lowering speed of the raw material. If a deviation occurs in the lowering speed of the raw material, a height difference occurs in the circumferential direction on the raw material deposition surface. The raw material is charged so as to be axially symmetrical about the center of the blast furnace, but if a height difference in the circumferential direction occurs on the deposition surface of the raw material, the thickness of the ore / coke layer formed by the charging is reduced. Direction and the hot ascending gas flow is offset from the furnace center axis.

  In addition, when a circumferential deviation occurs in the descending speed of the raw material, a deviation also occurs in the process of heating and reducing the raw material, and the heat balance in the blast furnace is disrupted in the circumferential direction. Tap hole deviations with different hot metal temperatures occur. A lower limit value is set for the temperature of the hot metal that is tapped from the tap hole, and the temperature is controlled so as not to fall below the lower limit value. For this reason, when a tap hole deviation occurs, the hot metal temperature on the low temperature side is managed so as not to fall below the lower limit, so that the hot metal temperature on the high temperature side becomes too high and the reducing material ratio of the entire blast furnace increases. It becomes a factor of uneconomic.

  As a device for detecting a deviation of a high temperature rising gas flow from a furnace center axis, a device in which a plurality of thermometers are installed in a radial direction of a furnace port portion is exemplified. In such an apparatus, usually, the temperature in one direction of diameter in a small to medium blast furnace and the direction of two diameters in a large blast furnace are measured with 5 to 6 thermometers in the radial direction. In such a device, when the direction of the displacement of the high-temperature rising gas flow is the direction in which the thermometer is installed, the displacement of the high-temperature rising gas flow can be detected. In the case where the thermometer is not installed, the deviation of the high-temperature rising gas flow cannot be detected, so that there is a problem that the detection capability is low.

  Further, in Patent Document 1, using a night-vision camera provided at the furnace opening of a blast furnace, a flowing part on the surface of a charge in a stock line is photographed, and the photographed image is processed to determine the position of the center of gravity of the flowing part. A technique for detecting the deviation between the position of the center of gravity and the center axis of the furnace is disclosed.

JP-A-3-17210

Masanori Shimizu and 4 others, "Solid flow under circulating non-uniform conditions in a blast furnace", Iron and Steel, 73 (1987), No. 15, 1996-2003 Makoto Nomura and 6 others, "Correspondence between circumferential heat level deviation and charge distribution deviation in bellless blast furnace", Iron and Steel, No. 68 (1982), S702

  According to the technology disclosed in Patent Document 1, the center of gravity of the fluidized portion is obtained by photographing the surface of the charge in the stock line with a night vision camera. However, due to the structure of the blast furnace, the night vision camera is placed on the central axis of the furnace. Since it cannot be installed, the surface of the charge is photographed from obliquely above. Since the charge is placed in a mortar shape such that the center is lower, the surface of the charge on the near side cannot be photographed with respect to the night vision camera from diagonally above. For this reason, there has been a problem that the positional accuracy of the center of gravity of the fluidized portion obtained by processing the photographed image is low, and the ability to detect the deviation between the center of gravity of the fluidized portion and the furnace center axis is low.

  The present invention has been made in view of the above-described problem, and an object of the present invention is to detect a circumferential deviation in a descending speed of a load, even if the descending speed in the circumferential direction occurs in any direction. It is an object of the present invention to provide a method of detecting a deviation of a load descending speed having a high detection capability.

The features of the present invention for solving such a problem are as follows.
(1) Using a plurality of ultrasonic sensors installed on the same plane of the blast furnace mouth, the temperature of a plurality of measurement points in the furnace mouth plane is measured to specify the position of the highest temperature part and the inside of the furnace. The height of the charged material is measured at four or more positions on the same circumference, and it is detected that the position of the highest temperature part is deviated from the central axis of the furnace, and corresponds to the position of the highest temperature part. When the height of the charge in the direction indicated by the arrow is lower than that in the other direction, it is detected that a deviation has occurred in the descent speed of the charge at a position corresponding to the position of the hottest part. A method of detecting the deviation of incoming descent speed.
(2) A position corresponding to the position of the highest temperature portion when the deviation detection method of the load descending speed according to (1) detects that a deviation occurs in the descending speed of the load. A blast furnace operating method in which the amount of pulverized coal blown from the tuyeres provided in the blast furnace is made larger than in other positions.
(3) A position corresponding to the position of the highest temperature part when the deviation detection method of the charge descending speed according to (1) detects that a deviation occurs in the descending speed of the charge. A blast furnace operating method in which the flow rate of air blown from the tuyere provided in the blast furnace is made smaller than in other positions.
(4) A position corresponding to the position of the highest temperature part when the deviation detection method of the charged object descending speed according to (1) detects that a deviation occurs in the descending speed of the charged object. A blast furnace operating method, wherein the amount of coke charged from the top hopper for charging the charge is larger than that of the hopper at the other position.

  According to the present invention, since the temperatures of a plurality of measurement points in the furnace port plane can be measured almost continuously using the ultrasonic sensor, the position of the highest temperature part in the furnace port plane can be specified continuously. For this reason, regardless of the direction in which the high-temperature rising gas flow deviates from the furnace central axis, the deviation is detected, and at the position corresponding to the highest temperature portion, a circumferential deviation occurs in the descending speed of the charged material. Can be detected.

It is a schematic diagram which shows the cross section of the gas temperature and the blast furnace in the state in which the high temperature rising gas flow is formed along the furnace center axis. It is a schematic diagram which shows the cross section of the gas temperature and the blast furnace in the state where the high temperature rising gas flow is formed in the position deviated from the furnace center axis. It is a figure showing an example of the ultrasonic temperature measurement system which can perform the deviation detection method of the charge descent speed concerning this embodiment. It is a figure which shows an example of the position of the mechanical type sowing meter installed in the furnace opening. It is a figure which shows the temperature distribution in the furnace opening part plane in the state where the highest temperature part coincided with the furnace center axis. It is a figure which shows the temperature distribution in the furnace opening part plane in the state where the highest temperature part deviated from the furnace center axis. FIG. 2 shows a top view and a front view of a raw material charging apparatus having three furnace hoppers.

  FIG. 1 is a schematic diagram showing a gas temperature and a cross section of a blast furnace in a state where a high-temperature rising gas flow is formed along a furnace central axis. FIG. 1A is a diagram illustrating a relationship between a cross-sectional position of the blast furnace and a gas temperature, and FIG. 1B is a schematic diagram illustrating a cross-section of the blast furnace.

  In the shaft portion of the blast furnace 30, the ore 32 charged from the furnace top is lowered while being heated and reduced by the high-temperature reducing gas rising from below. In order to stably realize the descent of the ore 32 in the shaft portion of the blast furnace 30, it is necessary to form a strong ascending gas flow in the furnace center axis 36 of the blast furnace 30 and to form a uniform gas flow in the circumferential direction of the blast furnace 30. It is good.

  For this reason, as shown in FIG. 1 (b), more coke 34 having a larger particle diameter than the ore 32 is provided on the furnace central axis side of the blast furnace 30, and the ore 32 and coke 34 are uniformly charged on the circumferential side. Thus, the distribution of the charge is adjusted so that the central portions thereof are lowered in a mortar shape. Thereby, as shown in FIG. 1A, a high-temperature rising gas flow is formed along the furnace central axis 36. In the present embodiment, the charge means ore and coke charged from the blast furnace furnace top.

  FIG. 2 is a schematic diagram showing a gas temperature and a cross section of a blast furnace in a state where a high-temperature rising gas flow is formed at a position shifted from the furnace center axis. FIG. 2A is a diagram illustrating a relationship between a cross-sectional position of the blast furnace and a gas temperature, and FIG. 2B is a schematic diagram illustrating a cross-section of the blast furnace.

  If the amount of air blown or the amount of pulverized coal blown from the tuyeres installed in the circumferential direction of the blast furnace 30 differs between tuyeres, or if there is a deviation in the coke consumption between tuyeres, A circumferential deviation also occurs in the descending speed of the charge, and a height difference occurs in the accumulation surface of the charge. Normally, the charge of the blast furnace 30 has a low central portion in a mortar shape, the deposition angle is equal in the circumferential direction, and the phenomenon that the charge falling at the same radial position flows into the furnace center is a circumferential phenomenon. Uniform in direction. On the other hand, if there is a height difference on the stacking surface of the charge, the stacking angle differs in the circumferential direction, and the coke 34 that has dropped at the same radial position also has a different flow phenomenon into the center in the circumferential direction. The place where the coke layer thickness is large and the deposition surface is low is shifted from the furnace center axis 36. FIG. 2B shows this state.

  As described above, a high-temperature rising gas flow is formed at a portion where the coke layer thickness is large. Therefore, if the portion where the coke layer thickness is large is displaced from the furnace center axis 36, the position of the high-temperature rising gas flow is also changed to the center of the furnace. Deviates from the axis 36. FIG. 2A shows this state. As described above, when a circumferential deviation occurs in the descending speed of the charge, the position of the high-temperature rising gas flow also shifts in the circumferential direction from the furnace center axis 36, so that the temperature distribution in the furnace port plane is substantially reduced. If the measurement can be performed continuously, the deviation of the high-temperature rising gas flow from the furnace center axis 36 can be detected at an early stage, whereby it is possible to early detect that a circumferential deviation has occurred in the descent speed of the charge. There is.

  On the other hand, even if blow-by occurs, a high-temperature rising gas flow is generated. In the blow-through, since the coke layer thickness is large as shown in FIG. 2 (b) and the place where the charge accumulation surface is low does not deviate from the furnace center axis 36, the descending speed of the charge decreases in the circumferential direction. In order to determine whether or not a deviation has occurred, the height of the accumulation surface of the charge in the furnace is also measured. Then, it is detected that the high-temperature rising gas flow has shifted from the furnace center axis 36, and the height of the deposition surface of the charge in the direction corresponding to the position where the high-temperature rising gas flow has shifted is higher than in other directions. Is also detected, it is detected that a circumferential deviation has occurred in the descent speed of the charge at the position. As described above, by detecting that the deviation in the circumferential direction has occurred based on the position of the high-temperature rising gas flow and the height of the deposition surface of the charge, the descent speed of the charge in the circumferential direction is reduced. It has been found that the occurrence of the deviation can be detected with high accuracy, and the present invention has been completed. Hereinafter, the present invention will be described through embodiments of the present invention.

  FIG. 3 shows an example of an ultrasonic temperature measurement system that can execute the method for detecting a deviation of the charge descending speed according to the present embodiment. The ultrasonic temperature measurement system 10 includes ten ultrasonic sensors 12 provided at equal intervals on the same plane along the furnace opening of the blast furnace 30, a processing device 14, and four mechanical sowing meters 22. The ultrasonic sensor 12 has a transmitter for transmitting an ultrasonic wave and a receiver for receiving the transmitted ultrasonic wave. Further, the processing device 14 includes a control unit 16, a display unit 18, and a storage unit 20.

  The processing device 14 is, for example, a general-purpose computer such as a workstation or a personal computer. The control unit 16 is, for example, a CPU or the like, and controls the operation of the ultrasonic temperature measurement system 10 using a program or data stored in the storage unit 20 and executes a predetermined calculation. The display unit 18 is, for example, an LCD or a CRT display. The storage unit 20 is, for example, a flash memory that can be updated and recorded, an information recording medium such as a hard disk or a memory card that is built-in or connected by a data communication terminal, and a read / write device therefor. In the storage unit 20, programs for realizing various functions of the ultrasonic temperature measurement system 10, data used during execution of the programs, and the like are stored in advance.

  During the operation of the blast furnace, an ultrasonic wave is transmitted from an arbitrary ultrasonic sensor 12, and the ultrasonic waves are received by all the other ultrasonic sensors 12. Transmission of an ultrasonic wave from the ultrasonic sensor 12 is repeatedly executed, for example, clockwise from an arbitrary ultrasonic sensor 12 under the control of the control unit 16. Each ultrasonic sensor 12 outputs to the control unit 16 the transmission time at which the ultrasonic wave was transmitted or the reception time at which the ultrasonic wave was received.

  Assuming that nine reception times corresponding to one transmission time are nine data and these nine data are one set of data, the control unit 16 acquires ten sets of data from the ten ultrasonic sensors 12. The control unit 16 reads the distance between the respective ultrasonic sensors 12 stored in the storage unit 20 in advance, and uses the transmission time, the reception time, and the distance between the ultrasonic sensors 12 to store the respective ultrasonic sensors 12. Calculate the speed of sound between them. Since the sound speed changes depending on the temperature of the furnace port space, the temperature between the ultrasonic sensors 12 can be calculated by the following equation (1).

C = 331.5 × ((273 + T) / 273) (1)
In the equation (1), C is the speed of sound (m / s) between the ultrasonic sensors 12, and T is the temperature (° C.) between the ultrasonic sensors 12. In addition, in the calculation of the expression (1), a correction based on the components and the pressure of the furnace top gas may be added in order to further increase the accuracy.

  The control unit 16 uses the temperature between the ultrasonic sensors 12 to calculate the temperatures at a plurality of measurement points where lines connecting the ultrasonic sensors 12 intersect. The control unit 16 may, for example, reproduce the reception time between the ultrasonic sensors 12 based on the sum of the times (functions of temperature) of the plurality of measurement points and the known distance to the plurality of measurement points. Calculate so that you can.

  It is preferable that the transmission and reception of the ultrasonic wave from the ultrasonic sensor 12 be performed in a short time as long as the accuracy can be maintained. In the present embodiment, for example, the ultrasonic wave is transmitted from one ultrasonic sensor 12 for 4 seconds while the other ultrasonic sensor 12 receives the ultrasonic wave. Thereafter, an interval of 2 seconds is set, and transmission of an ultrasonic wave from another ultrasonic sensor 12 and reception by an ultrasonic sensor other than the other ultrasonic sensor 12 are similarly repeated. In the example shown in FIG. 1, since ten ultrasonic sensors 12 are provided, the control unit 16 calculates the temperatures of a plurality of measurement points in the furnace port plane every 60 seconds.

  When calculating the temperature of the plurality of measurement points in the furnace port plane, the control unit 16 interpolates the temperature between the measurement points assuming that the temperature between the plurality of measurement points changes in proportion to the distance. A temperature distribution is created by dividing the plane of the furnace opening into temperature regions of 100 ° C., and the temperature distribution is displayed on the display unit 18. Thereby, the user can confirm the temperature distribution in the furnace port plane. Further, the control unit 16 repeatedly executes the above-described operation to calculate the temperature in the furnace port plane, and updates the temperature distribution in the furnace port plane displayed on the display unit 18. In this manner, the ultrasonic temperature measurement system 10 measures the temperature distribution in the plane of the furnace opening substantially continuously.

  In the present embodiment, the ultrasonic temperature measurement system 10 includes ten ultrasonic sensors 12. While transmitting the ultrasonic wave from one ultrasonic sensor 12 for 4 seconds, the ultrasonic wave is received by the other ultrasonic sensor 12, and the interval is set for 2 seconds thereafter, the control unit 16 acquires 90 data in 60 seconds. However, of the 90 data, 45 data are duplicated data obtained by measuring the same ultrasonic sensor 12 in reverse. That is, one set of data obtained in the first measurement has no overlap, but data that overlaps with the previous measurement included in one set of data from the second and subsequent measurements increases by one.

  As described above, the overlapping data increases each time the measurement is repeated. Therefore, when updating the temperature distribution in the furnace opening plane, the data in the furnace opening plane is updated every 30 seconds using the previous data. It is preferable to update the temperature distribution, and it is more preferable to update the temperature distribution in the furnace port plane every time the control unit 16 acquires one set of data, that is, every 6 seconds.

  FIG. 4 is a diagram showing an example of the position of a mechanical sowing meter installed at the furnace opening. For example, the four mechanical souding meters 22 are arranged at the center of a line connecting the furnace center axis in the furnace opening plane and points on the furnace circumference of east (W) west (E) south (S) north (N). And the height of the deposition surface of the charge in the furnace is measured at four or more positions on the same circumference. In addition, the position where the mechanical Saudi meter is provided is not limited to the above center, and is located on the same circumference where the distance from the furnace central axis to each mechanical Saudi meter is equal, and is located in the circumferential direction with respect to the furnace central axis. May be provided at a position where an angle between two adjacent mechanical sowing meters 22 is within a range of 90 ° ± 20 °.

  The measurement by the mechanical type sowing meter 22 is executed at predetermined time intervals under the control of the control unit 16. It is preferable that the predetermined time measured by the mechanical type sowing meter 22 is the same as the time for updating the temperature distribution in the furnace port plane, but the temperature distribution in the furnace port plane is updated in a short time. In this case, the temperature distribution may not necessarily be the same as the time at which the temperature distribution in the furnace opening plane is updated.

  Each of the mechanical sowing meters 22 measures the height of the accumulation surface of the charge, and outputs data indicating the height of the accumulation surface of the charge together with the identification number of the mechanical sowing meter 22 to the control unit 16. Output to When the control unit 16 obtains the data indicating the height of the charge output from the mechanical type sowing meter 22, the control unit 16 compares the data and outputs the data with the lowest height of the stacking surface of the charge. The identification number of the expression sawing meter 22 is specified. The storage unit 20 stores in advance a table in which the identification number of the mechanical sowing meter 22 is associated with the direction in which the mechanical sowing meter 22 to which the identification number is assigned is installed. Referring to the table, the direction in which the mechanical sawing meter 22 that outputs the data with the lowest height of the charged surface is provided, that is, the height of the stacked surface of the charged material is different from the other direction. Identify a direction that is lower than the direction.

  The control unit 16 specifies the position of the highest temperature portion, which is the highest temperature region in the temperature distribution in the furnace port plane, every time the temperature distribution in the furnace port plane is updated. The control unit 16 determines whether or not the position is at the position of the furnace center axis in the plane of the furnace opening. When the position of the highest temperature part is the position of the furnace center axis, the control unit 16 determines that there is no circumferential deviation in the descending speed of the charge.

  In addition, the position of the specified highest temperature part is the case where the position of the highest temperature part is not the position of the furnace center axis, the circumferential direction of the position shifted from the highest temperature part, and the deposition surface of the charge. When the height specified is lower than the other direction and the direction specified is equal, the control unit 16 determines that a circumferential deviation occurs in the descending speed of the charge at the position corresponding to the position of the hottest part. Judge that In this case, the control unit 16 displays, for example, on the display unit 18 that a circumferential deviation has occurred in the descending speed of the load.

  On the other hand, even if the specified position of the highest temperature part is not the position of the furnace center axis, the circumferential direction of the position shifted from the highest temperature part and the accumulation of the charge When the height of the surface is different from the direction specified as being lower than the other directions, the control unit 16 determines that there is no circumferential deviation in the descending speed of the load.

  As described above, the method for detecting the deviation of the charged material descending speed according to the present embodiment includes the method of detecting the charged material at four or more points on the same circumference as the position of the highest temperature part in the temperature distribution in the furnace opening plane. It is detected whether or not the descending speed of the charged object has a deviation in the circumferential direction from the height of the accumulation surface. Due to this, no matter what direction the circumferential deviation occurs in the descending speed of the charge in the furnace, a circumferential deviation occurs in the descending speed of the charge at the position corresponding to the highest temperature part. Can be detected. In addition, the temperature distribution over the entire furnace opening plane can be measured almost continuously, and the deviation of the position of the highest temperature part from the furnace center axis can be detected almost continuously. , It is possible to accurately and early detect the deviation of the descending speed in the circumferential direction.

  Further, when it is detected by the method of detecting a deviation of the charge descending speed according to the present embodiment that a circumferential deviation has occurred in the descending speed of the charge, the deviation is detected in the descending speed of the charge. The amount of the pulverized coal blown from the tuyere that blows the pulverized coal into the generated position may be larger than at other positions. As described in Non-Patent Literature 1, in a blast furnace, the lowering speed of the charge on the side opposite to the direction in which the coke consumption is small increases. Utilizing this characteristic, there was a deviation in the descending speed of the charge in the circumferential direction, that is, the amount of pulverized coal to be blown into the position of the hottest part where the lowering speed of the charge was faster than other positions By increasing, the coke consumption at the position can be reduced. This makes it possible to increase the descending speed of the charge on the side facing the position of the highest temperature portion, and eliminate the circumferential deviation of the decrease speed of the charge.

  Further, when it is detected by the method of detecting a deviation of the charge descending speed according to the present embodiment that a circumferential deviation has occurred in the descending speed of the charge, the deviation is detected in the descending speed of the charge. The flow rate of air blown from the tuyere provided at the position where the air flow occurs may be smaller than at other positions. A circumferential deviation occurred in the lowering speed of the charge, that is, by reducing the flow rate of air blown to the position of the hottest part where the lowering speed of the charge was faster than other positions, Coke consumption can be reduced. This makes it possible to increase the descending speed of the charge on the side facing the position of the highest temperature portion, and eliminate the circumferential deviation of the decrease speed of the charge.

  Furthermore, when it is detected by the method of detecting a deviation of the charge descending speed according to the present embodiment that a circumferential deviation has occurred in the descending speed of the charge, the position corresponding to the position of the highest temperature part is detected. The coke 34 to be charged into the furnace top hopper for charging the raw materials into the furnace may be more than the furnace hoppers at other positions, and the coke 34 to be charged to the highest temperature part may be increased. As described in Non-Patent Document 2, in the blast furnace, when the coke ratio of the charge is increased, the consumption rate of the ore 32 is reduced even at the same blowing rate because the ore 32 is small, and the descent rate of the charge is also low. Become slow. For this reason, by increasing the coke 34 charged at the position of the hottest part and increasing the coke ratio, the descent speed of the charge at the position of the hottest part can be slowed down. The circumferential deviation of the descending speed can be eliminated.

  As described above, the method for detecting the deviation of the charged object descending speed according to the present embodiment can early detect that the deviation in the circumferential direction has occurred in the descending speed of the charged object. The remedial measures described above can be implemented before the impact is magnified. As a result, the raw material reduction state in the circumferential direction can be made uniform at an early stage, and stable blast furnace operation can be realized.

  Next, referring to FIG. 5 and FIG. 6, the charge descending speed according to the present embodiment will be compared with a conventional device using a device in which a thermometer is installed in the radial direction of the furnace opening. A method of detecting a deviation will be described. FIG. 5 is a diagram showing a temperature distribution in a furnace port plane in a state where the highest temperature part is coincident with the furnace center axis. FIG. 6 is a diagram showing a temperature distribution in a furnace port plane in a state where the highest temperature part is shifted from the furnace center axis. In the examples shown in FIGS. 5 and 6, six thermometers 40 are provided on the line (1), the line (2), the line (3), and the line (4), and the furnace is used by using the thermometers. In addition to measuring the temperature of the mouth space, four mechanical sounding meters 22 are provided at the positions shown in FIG. 4, and the height of the stacking surface of the charge in the furnace is set at four or more points on the same circumference. It is measured in.

  FIG. 5A is a diagram showing the temperature distribution in the furnace port plane and the positions of the temperature measuring points measured by the thermometer 40. FIG. 5B is a graph showing the temperature changes of the lines (1) to (4) measured by the thermometer 40.

  In the example shown in FIG. 5, the position of the temperature region of 500 ° C. or higher, which is the highest temperature portion, coincides with the furnace center axis. For this reason, there is no deviation in the circumferential direction in the descending speed of the charge, which indicates that stable blast furnace operation is being performed. In this state, the layer thickness ratio of coke 34 to ore 32 on the furnace center axis side is increased by charge distribution adjustment, a high-temperature gas flow is formed on the furnace center axis side, and the furnace wall side is formed. A cold gas stream is formed. In this case, as shown in FIG. 5 (b), the temperature of the furnace port space on the furnace center axis side is high and the furnace port space on the furnace wall side is high even when measurement is performed by a device provided with a thermometer. Is low in all of the lines (1) to (4).

  FIG. 6A is a diagram showing the temperature distribution in the plane of the furnace opening and the position where the thermometer 40 is provided. FIG. 6B is a graph showing temperature changes of the lines (1) to (4) measured by the thermometer 40.

  In the example shown in FIG. 6, the position of the temperature region of 500 ° C. or higher, which is the highest temperature portion, is shifted in the N direction from the furnace center axis. Further, it is assumed that the height of the accumulation surface of the charge in the N direction measured by the mechanical type sowing meter 22 is the lowest. For this reason, the control unit 16 determines that a deviation in the circumferential direction has occurred in the descending speed of the charge at the position of the highest temperature part shifted in the N direction.

  On the other hand, in a device equipped with a thermometer, as shown in FIG. 6B, although there is a slight temperature difference in each direction, the blast furnace operation in which the temperature of the furnace opening space on the furnace central axis side is stable is stable. It only shows that it is lower than the temperature of the hour (FIG. 5 (a)). Since the decrease in the temperature of the furnace mouth space on the furnace central axis side also occurs due to the decrease in the central flow, discrimination between the circumferential deviation in the descending speed of the charge and the central flow decrease without circumferential deviation Becomes difficult. Here, the decrease in the central flow is a phenomenon in which the momentum of the ascending gas flow on the furnace central axis side decreases, and is considered to be caused by an increase in the ore layer thickness on the furnace central axis side due to a decrease in the deposition angle of the ore 32 and the like. ing.

  In order to correct the decrease in the central flow, usually, the charging pattern of the raw material is changed, and the coke 34 charged on the furnace central axis side is increased to improve the air permeability on the furnace central axis side. However, this measure cannot eliminate the circumferential deviation of the descending speed of the charge. In the case where the circumferential deviation of the descending speed of the charged material occurs, if the coke 34 charged on the furnace central axis side is increased, the coke layer thickness on the furnace central axis side becomes too thick and the gas on the furnace central side becomes too thick. In some cases, the flow becomes excessive, the gas reduction efficiency of the entire furnace is reduced, and the reducing material ratio is increased.

  On the other hand, in the method for detecting the deviation of the charge descending speed according to the present embodiment, since the temperature distribution in the plane of the furnace opening is used, even if the highest temperature part is deviated from the furnace central axis in any direction, the deviation is detected. Can be detected. Although the temperature of the hottest part decreases when the central flow decreases, the position of the hottest part does not deviate from the furnace center axis. By detecting the deviation of the load descending speed, the circumferential deviation of the charge descending speed and the decrease of the central flow can be easily determined, so that the circumferential deviation of the load descending speed can be determined with higher accuracy than the prior art. It can be said that it can be detected.

  In the example shown in FIG. 6, when it is detected by the method for detecting a deviation of the charged object descending speed according to the present embodiment that a circumferential deviation has occurred in the descending speed of the charged object, the maximum temperature is detected. The amount of pulverized coal blown from the tuyere that blows pulverized coal from the NE to NW (90 °) direction, which is the direction corresponding to the position of the part, is made larger than the tuyere installed in other directions. Specifically, the pulverized coal injection amount from the NE to NW directions is increased by 5.0% by mass, and NW to SW (90 °) in the other direction is set so that the pulverized coal injection amount in the entire furnace becomes constant. The amount of pulverized coal blown from tuyeres provided in the direction, SW-SE (90 °) direction and NE-SE (90 °) direction is reduced by 1.7% by mass, respectively. Thereby, the deviation in the circumferential direction of the descending speed of the charge in the NE to NW directions is eliminated, and the difference in the height of the charge in the N direction can be eliminated.

  The cause of the deviation in coke consumption is that there is a circumferential deviation in the ventilation resistance in the furnace, and the amount of air blown from the tuyere on the side with the lower ventilation resistance is relatively large. Probably caused. A circumferential deviation in coke consumption results in a circumferential deviation in the charge descent rate. For this reason, the method for detecting the deviation of the charge descending speed according to the present embodiment detects the occurrence of a circumferential deviation in the charge descending speed and adjusts the amount of pulverized coal blown from the tuyere. However, it is preferable to aim for a state in which there is no deviation in coke consumption. On the other hand, if there is a circumferential deviation in the amount of pulverized coal blown from the tuyeres, a circumferential deviation will occur in the coke consumption, which will cause a circumferential deviation in the charge descending speed. For this reason, even after applying a deviation in the circumferential direction to the pulverized coal injection amount, the pulverized coal injection amount is made uniform in all directions while applying the deviation detection method of the charge descending speed according to the present embodiment as needed. It is desirable to aim for a state.

  In the example shown in FIG. 6, when it is detected that a difference occurs in the descending speed of the charged object by the deviation detecting method of the charged object descending speed according to the present embodiment, the position of the highest temperature part is determined. The blowing amount from the corresponding directions NE to NW may be smaller than in other directions. By making the blowing amount smaller than in the other directions, the coke consumption in the NE to NW directions is reduced, and the descent speed of the charge in the SW to SE directions facing the NE to NW directions is increased. Thereby, the deviation of the descending speed of the charged object in the NE to NW directions can be eliminated, and the difference in the height of the charged object in the N direction can also be eliminated.

  Further, in the example shown in FIG. 6, when it is detected that a deviation occurs in the descending speed of the charged object by the deviation detection method of the charged object descending speed according to the present embodiment, the position of the highest temperature part is determined. The coke 34 charged from the top hopper for charging the raw material at the corresponding position may be larger than the coke 34 at the other positions. By increasing the coke 34 to be charged at the position corresponding to the position of the hottest part, the coke ratio of the position of the charge corresponding to the position of the hottest part is increased. If the coke ratio of the charge is increased, the consumption rate of the ore 32 is reduced even at the same blowing rate because the amount of the ore 32 is small, and the descent speed of the charge is also reduced. Thereby, the deviation of the descending speed of the charged object in the NE to NW directions can be eliminated, and the difference in the height of the charged object in the N direction can also be eliminated.

  Next, an example of a method of increasing the amount of coke 34 charged at a position corresponding to the position of the highest temperature portion will be described with reference to FIG. FIG. 7 shows a top view and a front view of a raw material charging apparatus having three furnace hoppers. 7A is a top view of the raw material charging device 50, and FIG. 7B is a front view of the raw material charging device 50. As shown in FIG. 7, a raw material charging device 50 having three furnace top hoppers 52, 54, 56, a flow rate adjusting gate 58, a collecting hopper 60, and a distribution chute 62 is provided above the blast furnace 30. Have been.

  It is assumed that in the method for detecting a deviation of the charge descending speed according to the present embodiment, it is detected that a deviation occurs in the descending speed of the charge in the direction in which the furnace top hopper 52 is provided. Normally, as shown in Table 1 below, coke 34 and ore 32 were charged alternately in the order of furnace top hoppers 52, 54 and 56, but as shown in Table 2 below, coke 34 The ore 32 was charged into the other top hoppers 54 and 56 to increase the coke ratio of the raw material charged in the direction of the top hopper 52. As a result, the descent speed of the charge at the position of the furnace top hopper 52 was reduced, the position of the highest temperature portion was coincident with the furnace central axis, and the difference in the height of the stacking surface of the charge was eliminated.

  The example shown in Table 2 is a method of providing a coke ratio deviation in the circumferential direction by operating the furnace top hopper, but is not limited thereto. For example, when charging the coke 34 into the furnace, The turning speed may be reduced when the distribution chute 62 is oriented in a direction in which the circumferential deviation of the descending speed occurs. This makes it possible to relatively increase the amount of coke 34 charged in the direction in which the circumferential speed deviation of the descent speed has occurred, and to increase the coke ratio in the direction.

  Further, when charging the charge from the furnace top hopper into the furnace, the flow rate adjustment gate 58 of the furnace top hopper is opened at the timing when the distribution chute 62 is directed in the direction in which the circumferential deviation of the descent speed occurs. The charging speed of the charge may be controlled by adjusting the degree. For example, when charging the ore 32 into the furnace, if the opening degree of the flow rate adjusting gate 58 is narrowed only in the direction in which the circumferential deviation of the descent speed occurs, the charged amount of the ore 32 in the direction is relatively small. And the coke ratio in that direction can be increased. Then, by increasing the coke ratio in the direction in which the circumferential deviation of the descending speed occurs, the descending speed of the charge can be reduced, and thereby, the circumferential deviation of the descending speed of the charge can be reduced. Can be eliminated.

  Note that, in the present embodiment, an example is shown in which the height of the deposition surface of the charge is measured by using the mechanical-type sounding meter 22, but the present invention is not limited to this. For example, the height of the deposition surface of the charge may be measured using a non-contact type device using a microwave or the like. In addition, the number of the mechanical type sowing gauges is four or more, and the height of the deposition surface of the charge in the furnace may be measured at four or more positions on the same circumference using these. In the case where four or more mechanical sowing gauges 22 are used, the angle formed by the furnace central axis and the two mechanical sowing gauges 22 adjacent in the circumferential direction is 360 ° / (number of mechanical sowing gauges). What is necessary is just to install the mechanical type sowing meter 22 so that it may be in the range of +/- 20 degrees.

  Further, in the present embodiment, an example has been described in which the highest temperature portion is the highest temperature region in the temperature distribution in the plane of the furnace port portion, but the present invention is not limited to this. For example, the highest temperature part may be a measurement point at which the highest temperature is calculated. In this case, the control unit 16 specifies the position of the measurement point at which the highest temperature is calculated, and determines whether or not the position is at the position of the furnace center axis in the furnace port plane.

  As described above, the present invention has been described using the embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments. It is apparent to those skilled in the art that various changes or improvements can be made to the above embodiment. It is apparent from the description of the appended claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

  In addition, the order of performing the operations in the devices, systems, and methods illustrated in the claims, the description, and the drawings is not particularly specified as “before”, “before”, and the like. It should be noted that as long as the output of this process is not used in a later process, it can be realized in any order. In the claims and the specification, the use of "first," "second," or the like for convenience does not imply that the steps must be performed in this order.

DESCRIPTION OF SYMBOLS 10 Ultrasonic temperature measurement system 12 Ultrasonic sensor 14 Processing device 16 Control part 18 Display part 20 Storage part 22 Mechanical-type saudiment meter 30 Blast furnace 32 Ore 34 Coke 36 Furnace central axis 40 Thermometer 50 Raw material charging device 52 Furnace top hopper 54 Furnace hopper 56 Furnace hopper 58 Flow rate adjustment gate 60 Collective hopper 62 Distribution chute

Claims (4)

Using a plurality of ultrasonic sensors installed on the same plane at the mouth of the blast furnace, measuring the temperature of a plurality of measurement points where lines connecting the plurality of ultrasonic sensors intersect to specify the position of the highest temperature part And measure the height of the charge in the furnace at four or more points on the same circumference centered on the furnace center axis .
Detecting that the position of the highest temperature portion is shifted from the furnace central axis, and, when the height of the charge in a direction corresponding to the position of the highest temperature portion is lower than other directions, A method for detecting a deviation in the charge descending speed, which detects that there is a deviation in the descending speed of the charge at a position corresponding to the position of the highest temperature part.   The method according to claim 1, wherein the method is provided at a position corresponding to the position of the highest temperature portion when it is detected that a deviation occurs in the descending speed of the charged object. A method of operating a blast furnace in which the amount of pulverized coal injected from the tuyere is larger than at other locations.   The method according to claim 1, wherein the method is provided at a position corresponding to the position of the highest temperature portion when it is detected that a deviation occurs in the descending speed of the charged object. A blast furnace operating method that reduces the flow rate of air blown from the tuyere that is blown from other locations.   The method according to claim 1, wherein when a deviation in the descending speed of the charge is detected, the load is detected at a position corresponding to the position of the highest temperature part. A blast furnace operation method in which coke charged from a top hopper for charging a material is larger than that of a hopper at another position.