JP4225147B2 - Furnace wall surface deposit identification method and furnace wall repair method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for discriminating deposits on the inner wall of a furnace that affects the lifetime of an industrial furnace, and a method for repairing a furnace wall.
[0002]
[Prior art]
Examples of the deposits on the inner wall of the furnace that affect the life of the furnace of an industrial furnace include coke oven carbon in an iron making process. In the coke oven, the operation is repeated in which coal charged in the furnace is dry-distilled for a certain period of time, and the resulting red hot coke is discharged out of the furnace by a coke extrusion device. When such an operation is performed, carbon deposits on the inner wall surface of the coke oven carbonization chamber and grows unevenly. As this growth proceeds, some of the precipitated carbon may peel off and fall into the furnace.
[0003]
On the other hand, the refractory bricks constituting the wall surface are gradually eroded by mechanical and thermal impacts when coal is introduced, or part of the refractory brick is peeled off together with the carbon grown on the wall surface. In this way, the wall surface becomes uneven, which causes clogging of the kiln during the coke extrusion operation. This clogging of the kiln not only lowers the operation efficiency of the coke oven, but also places a heavy load on the furnace body and further shortens the life of the furnace body. In particular, when carbon that adheres to and grows on the inner wall surface of the furnace is peeled off, the level difference due to the unevenness generated on the wall surface is often increased, so that there is a high possibility that kiln clogging is likely to occur during coke extrusion. Therefore, maintaining the smoothness of the wall surface in the coke oven carbonization chamber is very important in the operation of the coke oven.
[0004]
In the current operation, it is inevitable that the coke oven is uneven. In order to extend the life of the furnace body as long as possible, it is necessary to grasp the unevenness generated on the wall surface and appropriately perform repairs to smooth the unevenness efficiently.
[0005]
As a conventional technique for grasping the unevenness of the furnace wall in the coke oven, for example, there is a coke oven furnace wall shape measuring method as disclosed in JP-A-2002-080852 (Patent Document 1). FIG. 6 is a configuration diagram of a coke oven furnace wall shape measuring apparatus disclosed in Patent Document 1.
[0006]
6, 7, and 8 are three non-contact distance measuring means that measure the distance from each antenna to the carbonization chamber wall surface by transmitting and receiving electromagnetic waves in the microwave or millimeter wave band, respectively. 1, 2 and 3 are antennas for the distance measuring devices 6, 7 and 8 to individually transmit and receive electromagnetic waves. 4 collectively shows three waveguides each having one end coupled to each of the antennas 1, 2, and 3. Reference numeral 5 denotes three coaxial cables that individually connect the other ends of the three waveguides and the three distance measuring devices 6, 7, and 8. The waveguide 4 and the coaxial cable 5 are sufficient so that the antennas 1, 2 and 3 are pushed together with the pushing ram tip 11 and the ram beam 18 and inserted into the carbonizing chamber so that the pushing / inserting operation is not hindered. Length.
[0007]
9 is a signal processing device for measuring the shape of the coke oven furnace wall, 10 is a coke oven wall surface, 13 is an extrusion ram position measuring device, 14 is a camera, and 15 is an image processing device. Reference numeral 16 denotes a pair of reference points (hereinafter referred to as furnace body reference bright points) provided in the furnace body. Here, a light emitting diode (LED) is provided at each point as a mark indicating each position of the furnace body reference point 16. Reference numeral 17 denotes a reference point indicating the antenna position (hereinafter referred to as an antenna position reference bright spot). Here, one semiconductor diode (for example, a laser diode LD) is provided as a marker for collectively indicating the positions of the antennas 1, 2, and 3. Both the light emitting diode and the semiconductor diode emit light toward the camera 14. Reference numeral 19 denotes a coke extrusion device which extrudes the ram beam 18 and inserts it into the coke oven.
[0008]
In the technique disclosed in Patent Document 1, the distance between the distance meter and the furnace wall is measured together with the extrusion operation of the extrusion ram with a non-contact distance meter attached to the tip of the extrusion ram. Also, the extrusion ram tip is assumed to meander in the kiln width direction of the coke oven along with the extrusion operation, but the furnace body standard luminescent spot attached to the furnace body and the antenna position reference luminescent spot at the tip of the extrusion ram, Take images sequentially with an image capturing means such as a camera installed on the extruder, find the center of gravity on the image with respect to the antenna position reference luminescent spot and the standard luminescent spot on the furnace body, and antenna position reference luminescent spot by meandering of the extrusion ram The change in position with respect to the furnace body reference bright spot is calculated. Thus, the furnace wall shape measurement can be performed, and the unevenness generated on the wall surface can be quantitatively grasped.
[0009]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-080852
[Problems to be solved by the invention]
However, even if the unevenness generated on the wall surface is grasped by the technique shown in Patent Document 1, the unevenness is caused by uneven growth of carbon, or by partial peeling of the grown carbon, The repair method differs depending on the wear and tear. In the case of local growth of carbon, or in the case of partial peeling of the grown carbon, repair such as carbon burnout is performed, and thermal spray repair is performed in the case of refractory brick wear. In the furnace wall shape measurement, it is possible to confirm the presence and position of the unevenness on the wall surface of the furnace from the measurement results, but identify the cause of the unevenness that occurred on the wall surface and select an appropriate repair method. It is impossible to perform efficient repairs.
[0011]
An object of the present invention is to solve the above-described problems and to provide a method for discriminating deposits on the inner wall of a furnace and a method for repairing a furnace wall that greatly contribute to the life extension of the furnace body.
[0012]
[Means for Solving the Problems]
The above problems are solved by the following invention.
[0013]
According to the first aspect of the present invention, in an industrial furnace in which adhesion of a substance having conductivity different from that constituting the wall surface occurs on the inner wall surface of the furnace, the electromagnetic wave transmitting / receiving antenna is scanned in a manner facing the inner wall surface of the furnace. And receiving the reflected signal of the electromagnetic wave signal emitted from the transmitting antenna from the inner wall of the furnace with the receiving antenna, and determining the presence or absence of surface deposits on the inner wall of the furnace from the intensity of the received reflected signal. This is a method for discriminating deposits on the furnace inner wall surface.
[0014]
Further, the invention according to claim 2 is the method of determining the deposit on the wall surface in the furnace according to claim 1, wherein the substance constituting the wall surface is an insulator and the deposit is an electric conductor. If the signal intensity is larger than a set threshold value, it is determined that there is an adhering substance, and if the signal intensity is smaller than the threshold value, it is determined that there is no adhering part .
[0015]
Further, the invention according to claim 3 is the method for determining the deposit on the wall surface in the furnace according to claim 1 , wherein the substance constituting the wall surface is an electric conductor and the deposit is an insulator. If the signal intensity is smaller than a set threshold value, it is determined that there is an adhering substance, and if it is larger than the threshold value, it is determined that there is no adhering part .
[0016]
Further, the invention described in claim 4 uses the furnace wall surface deposit determination method according to any one of claims 1 to 3 to perform furnace wall surface deposit discrimination, and the unevenness generated on the wall surface. It is a furnace wall repairing method characterized by grasping the cause of the problem and selecting and implementing a repairing method .
[0017]
Further, the invention according to claim 5 is the furnace wall repair method according to claim 4, wherein unevenness is generated on the inner wall surface of the furnace due to uneven growth of carbon, or a part of the grown carbon. The furnace wall repair method is characterized in that if the surface is peeled off from the wall surface and unevenness is generated, carbon drop repair is performed, and if unevenness occurs in the refractory brick constituting the furnace wall, brick repair is performed. is there.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below with reference to the drawings. First, FIG. 2 schematically shows the reception waveform of the electromagnetic wave signal reflected on the surface of the refractory brick (without carbon adhesion) and the reception waveform of the electromagnetic wave signal reflected on the carbon attached to the surface of the refractory brick (with carbon adhesion) simultaneously. Is. The horizontal axis represents the extrusion ram travel time (distance), the vertical axis represents the intensity of the reflected signal, and the vertical axis represents the result of a predetermined calculation performed on the analog output signal of 0 to 5 (V) of the electromagnetic wave signal. is there.
[0020]
As shown in FIG. 2, the magnitude of the reflected signal differs depending on whether or not carbon is attached to the wall surface. Can be determined. In FIG. 2, the carbon adhering to the inner wall of the furnace has conductivity, and conversely, the refractory bricks constituting the furnace wall have no conductivity. Therefore, when the reflected signal is larger than the threshold value, the adhering carbon is not present. When it adheres on the wall surface of the furnace wall and the magnitude of the reflected signal is smaller than the threshold value, it is determined that no deposit is present.
[0021]
FIG. 3 shows simultaneously the result of the furnace wall shape measurement using the coke oven furnace wall shape measurement method disclosed in Patent Document 1 and the magnitude of the reflected signal from the furnace wall. The horizontal axis represents the amount of progress of the extrusion ram, the left side of the vertical axis represents the furnace wall shape measurement result, that is, the distance from the furnace center axis (absolute amount of the furnace wall shape), and the right side represents the magnitude of the reflected signal. Moreover, the numerical value of the reflected signal intensity on the vertical axis represents the result of performing a predetermined calculation on the analog output signal of 0 to 5 (V) of the electromagnetic wave signal. The reflected signal intensity indicates the maximum value of the reflected waveform as shown in FIG. In FIG. 3, since the reflection signal is large in the entire section of the furnace inner wall surface, it can be determined that the carbon is adhered as a whole. There is a point where the magnitude of the reflected signal is locally reduced (the circled part in the figure), but this is because the electromagnetic wave is scattered by the shape of the inner wall of the furnace and the reflected signal can be received by the receiving antenna. In this case, it is possible to determine the deposit on the wall surface by smoothing the data.
[0022]
FIG. 4 simultaneously shows the result of measuring the shape of the furnace wall immediately after the carbon adhering to the furnace wall in the coke oven is burned off, and the magnitude of the reflected signal from the furnace wall. As in FIG. 3, the horizontal axis represents the amount of progress of the extrusion ram, the left side of the vertical axis represents the absolute amount of the furnace wall shape, and the right side represents the magnitude of the reflected signal. Moreover, the numerical value of the reflected signal intensity on the vertical axis represents the result of performing a predetermined calculation on the analog output signal of 0 to 5 (V) of the electromagnetic wave signal. Since the reflected signal intensity is smaller than in the case of FIG. 3, the carbon adhering to the inner wall surface of the furnace is burned off due to carbon burning, and the irregularities appearing in the furnace wall shape measurement result constitute the furnace wall. It can be determined that this is due to wear of the refractory bricks.
[0023]
FIG. 5 shows an example of reflected signal intensity data before carbon burning in a coke oven. The horizontal axis represents the amount of progress of the extrusion ram, and the vertical axis represents the magnitude of the reflected signal. Moreover, the numerical value of the reflected signal intensity on the vertical axis represents the result of performing a predetermined calculation on the analog output signal of 0 to 5 (V) of the electromagnetic wave signal. Focusing on the reflected signal intensity when the extrusion ram progress is between 580 and 860 cm, it can be seen that the reflected signal intensity in this section is extremely lower than the reflected signal intensity in the other sections. Since it can be determined that carbon is attached to the wall surface in other sections, it is possible to determine that the attached carbon is locally peeled in the section where the amount of progress of the extrusion ram is 580 to 860 cm. In addition, there is a part where the reflected signal is large (the part circled in the figure) in this section (attached carbon peeling part), but in this part, carbon that could not be peeled off remains on the furnace inner wall surface. It is thought that.
[0024]
In the present invention, in order to determine the presence / absence of deposits on the inner wall surface of the furnace, the electromagnetic wave transmitting / receiving antenna or the antenna part of the electromagnetic distance meter needs to scan a place sufficiently close to the furnace wall. A desirable distance between antenna furnace walls at this time is determined by the wavelength of the carrier frequency of the electromagnetic wave signal and the antenna shape, but in the example shown here, it is in the range of 150 to 300 mm.
[0025]
When scanning a point more than 300 mm away from the furnace wall, electromagnetic waves may be scattered depending on the surface condition of the inner wall surface of the furnace, making it impossible to efficiently receive a reflected signal. It will not be possible to determine whether there are any deposits on the top. On the other hand, if the distance is 150 mm or less, the distance between the antenna furnace walls becomes too close, and efficient reception cannot be performed due to the influence of multiple reflection or the like. In the example shown here, the distance from the antenna to the furnace wall is a minimum of 170 mm and a maximum of about 250 mm.
[0026]
With regard to the determination of the presence / absence of carbon adhesion, it is possible to determine the adhering matter when a threshold value is set for the reflected signal intensity. A human may check the pattern and set the threshold value, but the threshold value can be automatically set. For example, by checking the maximum signal intensity in the reflected signal intensity data of one kiln with respect to the data of each kiln and multiplying each data by a coefficient so that the maximum value is equal in each kiln, the unified threshold setting for all kilns can be made. realizable. The above is possible in software, but can also be realized in hardware. That is, it is also conceivable to insert an amplifier capable of changing the amplification factor or an attenuator capable of changing the attenuation factor for each kiln.
[0027]
As shown in FIG. 5, in order to determine that carbon is peeled off, the ambient reflection is within a range of 30 times or more of the minimum effective measurement range in the coke oven longitudinal direction determined by the data acquisition speed of the electromagnetic rangefinder with respect to the speed of the extrusion ram When the signal level is reduced to 1/10 or less, it is determined that peeling has occurred. In the example shown here, the minimum effective measurement range in the longitudinal direction is 10 mm.
[0028]
Next, FIG. 1 shows an example of a series of flows for determining the furnace wall surface deposits and selecting and executing the furnace wall repair method. First, in step 100, the wall surface shape is measured by measuring the shape of the wall surface in the furnace using an electromagnetic distance meter that scans the electromagnetic wave transmitting / receiving antenna so as to face the wall surface in the furnace. If it is determined that the furnace needs to be repaired due to large irregularities in the wall surface shape (step 101), the furnace wall surface deposits are determined in step 102.
[0029]
Here, when the reflected signal intensity is larger than the set threshold value, the flow proceeds to the flow of reflected signal intensity of step 110. On the other hand, when the reflected signal intensity is smaller than the set threshold value, the process proceeds to the flow of the reflected signal intensity low in step 120. In the case of step 110, it is determined that the wall surface unevenness is due to attached carbon (step 111), and the repair method of the carbon drop repair in step 112 is selected and executed. In general, for carbon removal repair, a method of burning off carbon with a flame or a method of cutting convex portions is selected and executed. In the case of step 120, it is determined that the wall surface unevenness is due to the refractory brick itself (step 121), and a brick repair method such as thermal spray repair of the refractory brick in step 122 is selected and executed.
[0030]
As shown in FIG. 3, the unevenness of the inner wall surface of the furnace caused by the uneven growth of the attached carbon is burnt down and repaired to smooth the wall surface. When the refractory brick itself is uneven as shown in FIG. 4, brick repair such as thermal spray repair is performed to smooth the wall surface. Further, when the carbon grown on the inner wall surface of the furnace as shown in FIG. 5 is locally peeled off, it is possible to quickly repair the carbon by burning off.
[0031]
The above explanation has been given for the case where deposits with conductivity adhere to the inner wall surface of the furnace that has no conductivity, but in the opposite case, that is, to the inner wall surface of the furnace with conductivity. The present invention can also be applied to cases where deposits that do not have conductivity are attached. That is, the present invention is effective when the dielectric constants of the furnace inner wall surface and the deposit are greatly different.
[0032]
【The invention's effect】
According to the present invention, in an industrial furnace, particularly a coke oven in an iron making process, the furnace wall shape is measured, and the electromagnetic wave reflection signal intensity from the furnace inner wall surface is measured to determine the deposit on the furnace wall surface. It is possible to make a significant contribution to the life extension of the furnace body by grasping the extent and cause of the unevenness on the wall surface and selecting an appropriate repair method to efficiently repair the wall surface. It becomes.
[Brief description of the drawings]
FIG. 1 is a flowchart illustrating an example of a furnace wall repair method according to the present invention.
FIG. 2 is a schematic diagram for explaining a method of discriminating furnace wall deposits.
FIG. 3 is a diagram for explaining a method for discriminating coke oven furnace wall deposits.
FIG. 4 is a diagram for explaining a method for discriminating coke oven furnace wall deposits.
FIG. 5 is a diagram for explaining a method for determining a peeling state of carbon attached to a furnace inner wall surface.
FIG. 6 is a diagram for explaining a conventional furnace wall shape measuring method.
[Explanation of symbols]
1, 2, 3 Antenna 4 Waveguide 5 Coaxial cable 6, 7, 8 Distance measuring device 9 Signal processing device 10 Coke oven carbonization chamber wall surface 11 Extrusion ram tip 12 Coke 13 Extrusion ram position measuring device 14 Camera 15 Image processing device 16 Furnace body standard bright spot 17 Antenna position reference bright spot 18 Ram beam 19 Extruder

Claims (5)

In an industrial furnace where a substance having conductivity different from that constituting the wall surface is deposited on the inner wall surface of the furnace, the electromagnetic wave transmitting / receiving antenna was scanned so as to face the inner wall surface of the furnace and emitted from the transmitting antenna. A method for discriminating a deposit on an inner wall of a furnace, wherein a reflected signal of the electromagnetic wave signal from the inner wall of the furnace is received by a receiving antenna, and the presence / absence of a deposit on the inner wall of the furnace is discriminated from the intensity of the received reflected signal. In the furnace wall surface deposit | attachment discrimination | determination method of Claim 1, when the substance which comprises a wall surface is an insulator and the deposit | attachment is an electrical conductor, if a reflected signal strength is larger than the set threshold value, it will be attached. It is determined that there is a kimono, and if it is smaller than the threshold value, it is determined that there is no adhering portion. In the furnace wall surface deposit | attachment discrimination | determination method of Claim 1, when the substance which comprises a wall surface is an electrical conductor and the deposit | attachment is an insulator, it is attached if the reflected signal intensity is smaller than the set threshold value. It is determined that there is a kimono, and if it is larger than the threshold value, it is determined that there is no adhering portion. Using the furnace wall surface deposit determination method according to any one of claims 1 to 3, the furnace wall surface deposit determination is performed, the cause of irregularities on the wall surface is grasped, and a repair method is selected and A furnace wall repairing method characterized by being implemented. The method for repairing a furnace wall according to claim 4, wherein unevenness occurs due to uneven growth of carbon on the inner wall surface of the furnace, or unevenness occurs when a part of the grown carbon peels from the wall surface. A method for repairing a furnace wall, comprising repairing a dropped carbon and repairing bricks when the refractory bricks constituting the furnace wall are uneven.

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