JP3855639B2 - Profile measurement method of blast furnace interior entrance surface - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to how to measure the shape of the surface of the blast furnace interior container (the profile).
[0002]
[Prior art and problems to be solved by the invention]
Generally, iron ore and coke are alternately charged from the top of the blast furnace as charges, and an ore layer and a coke layer are formed in the furnace. The ore layer and coke layer formed in the furnace gradually descend in the furnace. The iron ore is heated and reduced by the CO gas generated by the reaction between hot air blown from the tuyere and coke, and after forming a softened cohesive zone, it becomes droplets. The droplets, that is, the molten iron, pass between the coke layers and accumulate at the bottom of the furnace.
[0003]
It is very important to adjust the charge distribution in the furnace opening formed by iron ore and coke charged in the blast furnace to obtain an appropriate gas distribution. The profile of the furnace interior charge is determined by the moveable armor in the bell type charging device and the fall trajectory of the charging material through the distribution chute in the bellless charging device.
Usually, the charge in the furnace port portion has a mortar shape with a low central portion. The profile of the charge in the blast furnace is important information for the operation of the blast furnace, and a method for measuring the profile of the charge charged in the furnace has been developed and put into practical use.
[0004]
For example, in Japanese Patent Laid-Open No. 9-263809, a measurement lance is inserted in the furnace port space in the furnace port space, and a plurality of microwave antennas attached downward to the measurement lance are used to There has been proposed a method for estimating the surface profile by measuring the distance to the entrance surface and calculating the inclination angle of the insert surface based on the measured distance.
[0005]
Japanese Patent Publication No. 6-72921 discloses a high-frequency component and a low-frequency component of a beat signal obtained at each measurement point in a profile meter that detects the profile of the charge by moving the FM radar above the charge. And a circuit that detects a ratio of amplitudes of frequency components that have passed through each filter, and a method for obtaining a profile using an output from a distance calculation device when the amplitude ratio exceeds a predetermined threshold. It is disclosed.
[0006]
In Japanese Patent Laid-Open Nos. 56-1117080 and 56-117081, the weights are suspended at a plurality of positions in the longitudinal direction of the lance that penetrates the side wall of the vertical furnace and is inserted in the furnace caliber direction, There has been proposed a method of measuring the displacement of the surface layer distribution by placing a weight on the surface of the charge.
[0007]
By the way, in recent blast furnace operations, the ratio of using raw materials with inferior quality, such as fine-grained ore, has increased, and the properties of raw materials have changed greatly. It is easy to receive.
Also, a coke center charging method has been developed and implemented, in which only coke is charged into the center of the blast furnace, where the gas flow in the blast furnace is stabilized and the air permeability and liquid permeability of the core are improved. Yes.
[0008]
However, in the case of the method proposed in the aforementioned Japanese Patent Laid-Open No. 9-263809, Japanese Patent Publication No. 6-72921, Japanese Patent Laid-Open No. 56-111080 and Japanese Patent Laid-Open No. 56-117081, There is a problem that it is impossible to evaluate and discriminate the circumferential balance and the eccentricity. Each of these methods is a method of measuring the profile of the charge surface in only one direction around the axis of the furnace mouth, and the profile in the direction opposite to the one position is such that the furnace interior charge is concentric. If the position of the minimum point of the central part of the mortar-shaped charge is on the opposite azimuth side beyond the axis, because it is considered to be symmetric with the one-side profile However, there was a problem that it was not possible to correctly evaluate and discriminate the circumferential balance and eccentricity of the furnace interior.
[0009]
In “Steel Research” No. 317 (1985), a probe (lance) incorporating a microwave circuit is inserted in the furnace caliber direction at the furnace top of the blast furnace and moved to the surface of the charge while rotating and rotating. A method has been proposed for measuring the deposit shape on the charge surface by continuously measuring the distance. The probe operation mode at the time of measurement is “T mode” that measures the distribution of charges in three directions, “Surface mode” that grasps the charge surface profile equivalent to the approximate semicircle of the furnace, and the axis. There have been proposed three types of modes, a “descent speed mode”, in which the distribution of charges in one direction around is measured twice at predetermined time intervals.
[0010]
However, the method proposed in this “steel research” has the following problems. That is, in the “T mode”, profile measurement in three directions can be performed, but profile measurement in opposite directions beyond the axis cannot be performed.
In the “plane mode”, the profile of the charge surface equivalent to approximately a semicircle of the blast furnace can be grasped in a plane, and the purpose is to confirm the circumferential balance of the charge. Since it takes a long time to insert and measure, there is a problem that the charged material falls within the measured time and the circumferential balance of the charged material cannot be confirmed accurately. In addition, if the measurement time is long, the furnace top temperature rises due to the loading of the charge, so that the next charge needs to be put into the furnace. Therefore, this “surface mode” measurement method is not suitable for normal operation.
[0011]
In addition, the “descent speed mode” is a method of measuring the charge distribution at one position twice at a predetermined interval and calculating the descent speed distribution based on the level difference between the data. Similar to the method proposed in the above-mentioned JP-A-9-263809, JP-B-6-72921, JP-A-57-117080 and JP-A-56-117081, the opposite of the axis. It is not possible to perform profile measurement of the orientation to be performed.
[0012]
The measuring device used in the method proposed in the above “steel research” has a microwave antenna attached to the tip of the probe (lance), and a microwave oscillation circuit is arranged at the rear end of the probe. The antenna at the front end portion arranged and the microwave oscillation circuit at the rear end portion arranged outside the furnace are electromagnetically connected by using a waveguide incorporated in the probe. This device is advantageous in that a microwave oscillation circuit composed of electronic components that are vulnerable to heat (usually those used at 80 ° C or less) can be installed outside the furnace, but a long probe is covered with a waveguide. Since they are connected, there is a drawback that an error is likely to occur in the microwave distance signal due to the bending of the probe. As a distance measuring sensor, it is desirable that the waveguide be as short as possible.
[0013]
In recent operations using low grade ore and operations mainly using coke, it is necessary to control the furnace wall flow while ensuring the gas flow to the blast furnace shaft. For this reason, it is important to accurately grasp the charge profile in the vicinity of the blast furnace axis portion and control the load distribution, not the conventional profile information only in one direction around the axis.
[0014]
This invention is made | formed in view of such a situation, and makes a measurement lance run as the range of a furnace port radial direction within the range from the side of a furnace port part to a length of 1.25 times the furnace port radius. Therefore, even when the position of the minimum point at the center of the charge is eccentric from the axial center, this eccentricity can be detected accurately, and the profile of the charge can be detected accurately. An object of the present invention is to provide a method for measuring the profile of the interior entry surface.
[0015]
In addition, the present invention can grasp the central portion of the charge in a planar shape by measuring a circular range centered on the axis of the blast furnace and having a radius of 0.25 times the radius of the furnace opening. An object of the present invention is to provide a method of measuring the profile of the blast furnace interior entrance surface, which can detect the eccentricity of the minimum point of the charge more accurately.
[0018]
[Means for Solving the Problems]
The profile measuring method for the surface of the blast furnace interior according to the first aspect of the present invention is to insert a measuring lance from the side surface of the blast furnace opening toward the axis of the blast furnace, and use a distance measuring means provided on the measuring lance. In the method for measuring the profile of the charge inside the blast furnace, the distance to the charge surface is measured and the profile of the charge surface is measured. It is characterized by measuring the range up to 25 times the length.
[0019]
In the first invention, since the measurement is performed within a range from the side surface of the furnace port portion to a length of 1.25 times the radius of the furnace port, the position of the minimum point at the center of the charge is eccentric from the axis. In this case, the eccentricity can be detected with high accuracy, and the circumferential balance of the charge and the presence or absence of the eccentricity can always be tracked. Therefore, it is possible to accurately grasp the change in the profile of the charge surface, to prevent deterioration of the furnace condition of the blast furnace, and to stabilize the operation of the blast furnace. It has been confirmed that the position of the minimum point of the charge does not exceed the above range.
[0020]
The profile measurement method for the surface of the blast furnace interior according to the second aspect of the present invention is the method according to the first aspect, wherein a measurement is performed within a circular range centering on the axis and having a radius 0.25 times the radius of the furnace opening. It is characterized by.
In the second invention, since the central portion of the charge can be grasped in a planar shape, the eccentricity of the minimum point of the charge can be detected more accurately.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic diagram showing a profile measuring apparatus according to an embodiment of the present invention, in which 1 is a blast furnace. A refractory material 20 is lined on the inner surface of the blast furnace 1, and an ore layer 11 and a coke layer 12 are deposited on the inner side.
One end of the measurement lance 3 of the profile device of the present invention is provided with a microwave antenna 4 for transmitting and receiving microwaves. The microwave antenna 4 is connected to a microwave oscillation circuit 6 via a waveguide 5. Is connected. The microwave oscillation circuit 6 transmits a microwave to the microwave antenna 4 through the waveguide 5 by an FM-CW (frequency continuous modulation wave) method. The other end of the measuring lance 3 is mixed and detected by the microwave transmitted from the microwave antenna 4 and the microwave reflected by the charge surface 2 and received by the microwave antenna 4. A microwave signal processing circuit 7 for generating a beat signal corresponding to the level height of the object and obtaining a distance from the microwave antenna 4 to the charge is attached. An attachment side end portion of the microwave signal processing circuit 7 of the measurement lance 3 is attached to one end portion of the lance travel frame 10 via a lance travel mechanism 8 and a lance rotation mechanism 9 each including an electric or hydraulic actuator. .
[0026]
As shown in FIG. 1, the profile measuring device of the present invention is designed to be permanently installed at the furnace port of the blast furnace 1, but can be taken out of the furnace from the furnace if necessary. Thus, it is configured to be detachable. It has been confirmed that the permanent installation of the measurement lance 3 above the charge surface 2 in the blast furnace 1 has no problem in durability when the measurement lance 3 has a water-cooled jacket structure.
[0027]
The microwave oscillation circuit 6 composed of thermally weak electronic components is exposed to a high-temperature atmosphere in the blast furnace, but is housed in a measurement lance 3 having a water-cooled jacket structure, and nitrogen gas is also supplied from outside the furnace. So cool enough. Further, it is desirable to blow out nitrogen gas into the microwave antenna 4 and purge dust floating in the furnace to prevent dust from adhering to the radiation surface of the microwave antenna 4.
As described above, even if the measurement lance 3, the microwave antenna 4, and the microwave oscillation circuit 6 are exposed to a high temperature atmosphere in the blast furnace, it can be permanently installed in the blast furnace 1.
In this apparatus, since the microwave antenna 4 and the microwave oscillation circuit 6 can be installed close to each other, the waveguide 5 can be shortened. Therefore, the microwave distance signal is not affected by the deflection of the measurement lance 3.
[0028]
The measurement lance 3 inserted into the furnace port is run and turned by the control device 13 receiving a measurement request signal from the operation desk 14 and driving the lance running mechanism 8 and the lance turning mechanism 9. It ’s like that. A travel distance detector 18 and a rotation angle detector 19 are connected to the lance travel mechanism 8 and the lance rotation mechanism 9, respectively, so that the lance travel distance T and the lance rotation angle θ are detected. is there. The detected lance travel distance T, the lance rotation angle θ, and the signal of the distance H obtained by the microwave signal processing circuit 7 are output to the control device 13. The control device 13 outputs the lance travel distance T, the lance rotation angle θ, and the distance H to the data processing device 15, and the data processing device 15 performs data processing on this, and (x, y, z) orthogonal coordinate signals. The data is transmitted to the arithmetic unit 16 as a group. The computing unit 16 performs image processing, and an image is displayed on the image display unit 17 based on a signal output to the image display unit 17.
[0029]
In the profile measurement method according to this embodiment, using the profile measurement device, the measurement lance 3 is caused to travel within the range from the side surface of the furnace port portion to the length of (R + E) as the range in the furnace port radial direction, The profiles of the ore layer 11 and the coke layer 12 deposited in the blast furnace 1 are measured. Here, R represents the radius of the furnace opening, E represents the length exceeding the axis II, and is 0.25 times as long as R.
[0030]
For example, E is +1.25 m (5 × 0.25) in a large blast furnace having a furnace diameter of φ10 m shown in FIG. 3 described later. Usually, in this large blast furnace, it has been confirmed that the deviation e (minimum point of the charge distribution) of the charge distribution from the axis II of the blast furnace is 1 m at the maximum.
The measurement lance 3 is a cantilever support structure. When the measurement range is further expanded, the mechanical strength needs to be increased greatly even though it is a cooling structure, so E is 0.25 times the furnace port radius R. The length is limited.
[0031]
Then, the measurement lance 3 is run and rotated to measure within a circular range centered on the axis II and having a radius of 0.25 × R (R: furnace port radius). By measuring the axial center in a planar shape, it is possible to more accurately detect the deviation e of the charge distribution. As described above, it has been confirmed that the deviation e of the charge distribution falls within a circular range having a radius of 0.25 × R.
[0032]
In the method according to this embodiment, first, the control device 13 drives the lance travel mechanism 8 to travel the measurement lance 3, continuously transmits microwaves from the microwave antenna 4, and starts from the surface to be measured. The microwave signal processing circuit 7 mixes and detects the transmission wave and the reception wave, generates a beat signal corresponding to the level of the charge, and measures from the microwave antenna 4 to be measured. Find the distance H to the surface. The microwave to be used is generally an X band near 10 GHz, but a higher frequency may be used.
[0033]
When the measurement lance 3 reaches a position 0.25 times the furnace port radius R from the axis II, the lance travel mechanism 8 and the lance rotation mechanism 9 are driven to center the axis II. The distance H at each position in a circular range having a radius 0.25 times the furnace port radius R is obtained.
FIG. 2 is a schematic plan view showing a locus L of a position on the charged material surface 2 of the microwave transmitted from the measurement lance 3 of the profile measuring apparatus according to the embodiment of the present invention.
[0034]
The travel distance detector 18, the rotation angle detector 19, and the microwave signal processing circuit 7 output signals of the lance travel distance T, the lance rotation angle θ, and the distance H to the data processing device 15 via the control device 13. The data processing device 15 processes the data and outputs it to the computing unit 16 as a signal group of orthogonal coordinates of (x, y, z).
The computing unit 16 performs image processing based on the (x, y, z) orthogonal coordinate signal group input from the data processing device 15 and outputs a signal to the image display unit 17, which the image display unit 17 receives. The distribution image of the charge is displayed on the basis.
[0035]
FIG. 3 shows the ore layer 11 and the coke layer 12 in a large blast furnace with a diameter of φ10 m, measured as a range in the radial direction of the furnace port from the side surface of the furnace port to a position exceeding the axis II by 1 m. It is the graph which showed thickness distribution, a horizontal axis shows the furnace diameter direction distance from an axial center, and a vertical axis | shaft shows the position of the depth direction from a nominal stock level. In FIG. 3, the planar profile S for the semicircle inside the furnace is also shown.
FIG. 4 is a graph showing the relationship between the ore layer thickness / coke layer thickness and the furnace bore direction distance based on the layer thickness distribution of the ore layer 11 and the coke layer 12 shown in FIG.
[0036]
As shown in FIG. 3, the ore layer 11 and the coke layer 12 are deposited in a mortar shape having a low central portion, and the minimum point P of the charge distribution is shifted by e (approximately 0.5 m) from the axis II. I know that.
[0037]
In the method of the present invention, the minimum point P of the charge distribution can be specified from the profile S near the axis II obtained by combining the travel and rotation of the measurement lance 3.
In the conventional method of measuring the profile of only one direction around the axis of the furnace port, it is correct if the position of the minimum point P of the charge is on the opposite azimuth side beyond the axis II. Although there was a problem that the balance of the charged material could not be evaluated and discriminated, according to the method of the present invention, as described above, the position of the local minimum point P can be accurately detected, and the balance of the charged material can be detected. Can be accurately evaluated.
[0038]
In actual operation, profile measurement is performed about twice for each shift (8h), and the profile change of the charge surface 2 is monitored. Among the items of the charge profile measurement, the inclination angle and the charge distribution balance greatly affect the gas flow distribution, and thus are one of the indispensable indicators for determining the daily distribution adjustment. When the distribution balance of the charges is deviated and decentered, the gas flow distribution is deviated from the axial center II, the gas flow does not pass through the axial center II, and the gas utilization rate of the entire blast furnace 1 is reduced. Fuel costs will increase. In addition, there is a possibility of deteriorating furnace conditions. In order to prevent the deviation (eccentricity) of the charge distribution balance due to the raw material charging system, the bell-less charging device performs centering adjustment of the raw material flow from the furnace top raw material hopper to the distribution chute, In the charging device, the stroke of the movable armor is changed to adjust the load distribution. From the operational aspect, it is necessary to adjust the circumferential balance by adjusting the amount of circumferential air flow from the tuyere.
[0039]
In the profile measuring method of the present invention, as described above, the circumferential balance of the charge and the presence or absence of eccentricity can always be tracked, and the profile change of the charge surface 2 can be accurately grasped. Therefore, it is possible to prevent the deterioration of the blast furnace condition and stabilize the operation of the blast furnace.
[0040]
In the above embodiment, the distance H to the charge is measured using a microwave that can be measured in a non-contact manner with little influence of dust, heat, noise, light, etc., but is not limited thereto. Rather than applying a mechanical sounding device, a mechanical profile meter that repeats stopping of the measuring lance 3 and raising and lowering of the weight at each measurement point may be applied, and an optical laser may also be applied. Is possible.
[0041]
In the above embodiment, when the measurement lance 3 reaches the position 0.25 times the furnace port radius R from the axis II, the measurement lance 3 is centered on the axis II and the furnace port. Although the case where the profile of the charge surface 2 is obtained three-dimensionally within a circular range having a radius of 0.25 times the radius R is described, the measurement lance 3 is not rotated. The profile of the charge surface 2 may be obtained two-dimensionally by moving linearly. However, the local minimum point P of the charge can be accurately detected by measuring the vicinity of the axis II in a planar shape.
In addition, a three-dimensional profile of the charge surface 2 within a square range with the measuring lance 3 as the center and the length of 0.25 × 2 times the furnace port radius R as one side is obtained. It is preferable to run and rotate the measuring lance 3 at the same time.
[0042]
【The invention's effect】
As described above in detail, in the case of the first invention, since the measurement is performed within a range from the side surface of the furnace port portion to a length of 1.25 times the radius of the furnace port portion, the minimum point of the central portion of the charge is measured. Even when the position is eccentric from the axial center, this eccentricity can be detected with high accuracy, and the circumferential balance of the charge and the presence or absence of the eccentricity can always be tracked. Therefore, it is possible to accurately grasp the change in the profile of the charge surface, to prevent deterioration of the furnace condition of the blast furnace, and to stabilize the operation of the blast furnace.
[0043]
In the case of the second invention, since the central part of the charge can be grasped in a planar shape, the eccentricity of the minimum point of the charge can be detected more accurately.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a profile measuring apparatus according to the present invention.
FIG. 2 is a schematic plan view showing a locus of a position on a surface of a charge of a microwave transmitted from a measurement lance of the profile measuring apparatus according to the embodiment of the present invention.
[Fig. 3] Distribution of layer thickness of ore layer and coke layer in a large blast furnace with a diameter of φ10m, measured from the side surface of the furnace port to a position exceeding 1m from the axis II as the radial range of the furnace port It is the graph which showed.
FIG. 4 is a graph showing the relationship between ore layer thickness / coke layer thickness and furnace diameter direction distance.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Blast furnace 2 Charge surface 3 Measurement lance 4 Microwave antenna 5 Waveguide 6 Microwave oscillation circuit 7 Microwave signal processing circuit 8 Lance travel mechanism 9 Lance rotation mechanism 10 Lance travel frame 11 Ore layer 12 Coke layer 13 Control device 15 Data processing device 16 Calculator 17 Image display 18 Traveling distance detector 19 Rotating angle detector R Furnace port radius P Minimal point L Lance traveling / rotating trajectory E Measurement range e Deviation of charge from minimum axis II Blast furnace axis θ Rotation angle S Profile during lance rotation

Claims (2)

Insert a measurement lance from the blast furnace side of the blast furnace toward the center of the blast furnace, and measure the distance to the charge surface using the distance measuring means provided on the measurement lance. In the method of measuring the profile of the blast furnace interior entrance surface for measuring the profile of
A method for measuring a profile of an inner surface of a blast furnace interior, wherein a range from a side surface of the furnace port portion to a length of 1.25 times a radius of the furnace port is measured as a range in a furnace port diameter direction.   The method for measuring a profile of a blast furnace interior entrance surface according to claim 1, wherein the profile is measured in a circular range centered on the axis and having a radius of 0.25 times the radius of the furnace port.

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