JP7572616B2 - Method and device for monitoring cross tie rods in coke ovens - Google Patents

Description

The present invention relates to a method and device for monitoring coke oven cross tie rods.

Figure 4 is a diagram explaining a chamber-type coke oven. In a chamber-type coke oven 1, as shown in Figure 4, a large number of carbonization chambers 2 and combustion chambers 3 are arranged alternately, and oven walls are constructed of bricks between each carbonization chamber 2 and combustion chamber 3. The carbonization chamber 2 has a number of loading ports 25 on the furnace top side in the height direction Z, from which coal is loaded into the carbonization chamber 2. Here, the longitudinal direction of the carbonization chamber 2 is called the furnace length direction X. Also, the direction in which the multiple carbonization chambers are arranged is called the furnace length direction Y.

To prevent the brick structure constructed in this way from loosening, one or two backstays 4 are placed upright at both ends in the furnace length direction X, and the brick structure is restrained by the furnace clamping force between the backstays at both ends. In the furnace length direction Y, the backstays are placed corresponding to the combustion chamber placement section. The backstays are H-shaped steel with high rigidity. Between the backstays at both ends in the furnace length direction, two or as many as six steel bars called cross tie rods 5 are placed on the top and bottom, and these cross tie rods 5 and the backstays 4 are connected using springs 8 to generate a clamping force between the opposing backstays at both ends in the furnace length direction X, thereby restraining the brick structure between the backstays. Hereinafter, unless otherwise specified, in this specification, cross tie rod means the cross tie rod placed on the furnace top side.

The cross tie rod 5 is disposed in a groove or hole provided in the furnace top brick 21 (hereinafter, the groove or hole in which the cross tie rod 5 is disposed is collectively referred to as the "cross tie rod groove 22", see Figure 3). Therefore, the heat from the high temperature combustion chamber 3 and the carbonization chamber 2 is transmitted to the cross tie rod 5 through the furnace top brick 21, and the temperature of the cross tie rod 5 rises. As a result, the cross tie rod 5 stretches, the tension of the spring 8 decreases, and the restraining force of the backstay 4 cannot be maintained. Furthermore, the tensile allowable stress of the cross tie rod 5 decreases, and it may break (rupture).

When the restraining force of the cross tie rods 5 is reduced or eliminated in this way, the furnace body bricks that make up the coke oven 1 will expand in the furnace length direction due to temperature changes caused by repeated loading and unloading operations in each carbonization chamber 2, or the effects of unloading.

Patent Document 1 discloses a method and device for managing coke oven cross tie rods, which supplies air to the hollow section of the cross tie rod, which is a hollow steel pipe, and monitors one or both of a thermometer that measures the temperature of the cross tie rod or the exhaust air, and an anemometer that measures the wind speed of the exhaust air, thereby enabling quick detection of breakage of the cross tie rod in a coke oven.

JP 2020-015831 A

It is known that if a coke oven is left without noticing a broken cross tie rod, the furnace body will expand rapidly in the affected combustion chamber. Normally, the furnace body will expand for one year, but if the cross tie rod is left broken, it will expand in three days. As the furnace body expansion progresses, the strength of the oven walls will decrease and the frequency of brick breakage will increase. Furthermore, if many breaks occur, the rapid deterioration of the furnace body will progress even further.

In response to this, by adopting the technology described in Patent Document 1, it has become possible to quickly and timely detect the breakage of a cross tie rod. When a cross tie rod breaks, a tensioning jig is attached to the top of the furnace body in place of the cross tie rod and the furnace is tightened as an emergency measure to suppress the abnormal expansion of the coke oven. The cross tie rod is then replaced. However, during the period from when the cross tie rod breaks until the emergency measure is completed, there is no means to suppress the abnormal expansion of the furnace body, which shortens the life of the furnace.

The present invention aims to provide a method and device for monitoring coke oven cross tie rods that can detect the occurrence of creep deformation in the cross tie rods of coke ovens.

That is, the gist of the present invention is as follows.
(1) A cross tie rod disposed in a coke oven is measured by a temperature measuring means for measuring a temperature of the cross tie rod or a length measuring means for measuring a length of the cross tie rod;
A method for monitoring coke oven cross tie rods, characterized in that the occurrence of creep deformation is detected by analyzing the temperature history of the cross tie rod or the length change history of the cross tie rod accumulated by the measurement.
(2) A method for monitoring coke oven cross tie rods as described in (1), characterized in that an elapsed lifespan indicating the progress of the creep deformation is predicted by analysis based on the temperature history of the cross tie rod.
(3) The method for monitoring a coke oven cross tie rod according to (2), further comprising predicting a time when the cross tie rod will break based on the elapsed life.
(4) A method for monitoring a coke oven cross tie rod described in any one of (1) to (3), characterized in that, instead of the temperature measuring means, continuous measurements are performed by a temperature measuring means installed in the coke oven to estimate the temperature of the cross tie rod.
(5) Instead of the length measuring means, the measurement is performed by a physical quantity measuring means that measures a physical quantity that changes in response to a change in the length of the cross tie rod,
The method for monitoring coke oven cross tie rods according to (1), characterized in that analysis is performed based on the history of changes in the physical quantities instead of the history of changes in the length of the cross tie rods.

(6) A cross tie rod provided in a coke oven includes a temperature measuring means for measuring a temperature of the cross tie rod, and a cross tie rod breakage prediction device for predicting a breakage time of the cross tie rod,
The temperature is measured by the temperature measuring means,
The cross tie rod breakage prediction device is a coke oven cross tie rod monitoring device characterized in that it performs analysis based on the temperature history of the cross tie rod accumulated by measurement to grasp the progress of creep deformation, predicts when the cross tie rod will break, and outputs the predicted time when the cross tie rod will break.
(7) A coke oven system includes a length measuring means for measuring the length of a cross tie rod disposed in the coke oven, and an analysis means for performing an analysis based on the measurement value measured by the length measuring means,
A coke oven cross tie rod monitoring device, characterized in that the analysis means detects the occurrence of creep deformation based on a history of changes in length of the cross tie rod accumulated by measurement.

The present invention measures the cross tie rods placed in a coke oven using a temperature measuring means that measures the temperature of the cross tie rods or a length measuring means that measures the length of the cross tie rods, and detects the occurrence of creep deformation from the measurement results. By detecting the occurrence of creep deformation, the cross tie rods can be replaced before they break, making it possible to suppress abnormal expansion of the furnace body.

1A to 1C are explanatory diagrams illustrating stages of creep deformation. FIG. 2 is a creep characteristic diagram showing the relationship between load stress, time to fracture, and temperature. FIG. 2 is a partial plan view showing the monitoring method and device for a coke oven cross tie rod of the present invention. 1A is a side cross-sectional view of a coke oven, FIG. 1B is a partial plan view, and FIG. 1C is a partial front view. FIG. 1 is a diagram showing the relationship between temperature Tx [° C.] and rupture time L [hr].

The following describes a preferred embodiment of the present invention. Note that in this specification and drawings, components that have substantially the same functional configuration are designated by the same reference numerals to avoid redundant description.

The breakage of the cross tie rod 5 is believed to be due to creep deformation. As shown in Figure 4, the cross tie rod 5 is connected to the backstay 4 via a furnace tightening spring 8. The backstay 4 is usually an H-shaped steel that is installed vertically at both ends of the combustion chamber 3 (the pusher side 35 and the guide car side 36). The cross tie rod 5 applies a tightening force to the backstay 4 in the furnace length direction X by the furnace tightening spring 8. Therefore, stress is continuously acting on the cross tie rod 5.

The cross tie rod 5 is also disposed through a cross tie rod groove 22 provided in the furnace brick 21. Therefore, due to the effect of the temperature rise caused by the combustion of the combustion gas in the combustion chamber 3, the location where the cross tie rod 5 is disposed is also in a high-temperature environment. Furthermore, for example, coke oven gas (combustible gas) leaking into the cross tie rod groove 22 due to a broken brick joint or the like may burn, causing a further rise in temperature.

In this way, sustained stress in a high-temperature environment causes creep deformation and breakage of the cross tie rod 5. Generally, the higher the temperature and stress, the faster the deformation rate becomes, and the amount of deformation increases over time, as shown below.

Figure 1 is an explanatory diagram illustrating the stages of creep deformation at a given temperature and stress. Creep deformation is considered to have three stages: the first stage, which takes the form of transition creep, the second stage, which takes the form of steady creep, and the third stage, which takes the form of accelerated creep. In the second stage, the creep rate (amount of deformation per unit time) is constant, but in the third stage, the creep rate increases over time, leading to rupture in a short period of time. By capturing the change in creep rate (the magnitude of change in length of the cross tie rod 5), it is possible to predict that creep deformation has progressed to the third stage and that rupture is imminent.

In addition, the time until rupture due to creep occurs (creep life) can be predicted using a relationship diagram showing the creep characteristics of the steel material used in the cross tie rod 5 (hereinafter referred to as the creep characteristic diagram), as shown below.
FIG. 2 is a creep characteristic diagram showing the relationship between the load stress (MPa) and the time to fracture (h) in a certain temperature environment (500°C, 550°C, 600°C, 650°C) for STBA22, which is an example of the material of the cross tie rod 5 (National Institute for Materials Science, Creep Data Sheet, searched on August 6, 2020 <URL: https://smds.nims.go.jp/creep/>). n in FIG. 2 indicates the number of creep rupture data at each temperature. Note that, as the material of the cross tie rod 5, STBA12-26, which is an alloy steel pipe for boilers and heat exchangers specified in JIS G3462, STPA12-26, which is an alloy steel pipe for piping specified in JIS G3458, and the like are used.

The load stress of the cross tie rod 5 is generally 50 to 120 MPa. For example, when the load stress is 100 MPa, as shown in FIG. 2, if the temperature environment of the cross tie rod 5 is 550°C, the lifespan is about 480 days, and if it is 600°C, the lifespan is about 17 days. Also, according to FIG. 2, if the cross tie rod is held at 550°C for 240 days, it is predicted that it can be used for another 240 days without breaking if it is held at 550°C thereafter. For example, if the temperature is raised to 600°C after being held at 550°C for 240 days (240 days/480 days=1/2), which is half the lifespan at 550°C (480 days), it is considered that half the lifespan has passed, and the remaining lifespan (remaining lifespan) is predicted to be 8.5 days, which is half the lifespan at 600°C (17 days).

There are two possible methods for detecting creep deformation of the cross tie rod 5. One is to predict when it will break (fracture) in the third stage based on the temperature history of the cross tie rod 5. The other is to detect when it has progressed to the third stage by capturing the change in the length of the cross tie rod 5.

Therefore, in the cross tie rod monitoring method of the present invention, measurements are performed using a temperature measurement means for measuring the temperature of the cross tie rod 5 or a length measurement means for measuring the length of the cross tie rod 5, and analysis is performed based on the temperature history of the cross tie rod or the length change history of the cross tie rod accumulated by the measurements to detect the occurrence of creep deformation.

The cross tie rod monitoring device of the present invention includes a temperature measurement means for measuring the temperature of the cross tie rod placed in the coke oven, and a cross tie rod breakage prediction device for predicting when the cross tie rod will break, and is configured to perform measurements using the temperature measurement means, and the cross tie rod breakage prediction device performs analysis based on the temperature history of the cross tie rod accumulated by measurement to grasp the progress of creep deformation, predict when the cross tie rod will break, and output the predicted breakage time of the cross tie rod. The cross tie rod placed in the coke oven may also include a length measurement means for measuring the length of the cross tie rod, and an analysis means for performing analysis based on the measurement value measured by the length measurement means, and the analysis means may be configured to detect the occurrence of creep deformation based on the length change history of the cross tie rod accumulated by measurement.

In the cross tie rod monitoring method or cross tie rod monitoring device that predicts the breakage time of the cross tie rod using a temperature measuring means, an analysis is performed using a creep characteristic diagram of the material of the cross tie rod 5 based on the measured temperature measured by the temperature measuring means, the accumulated time at that measured temperature, and (the temperature history of the cross tie rod 5), to determine the elapsed life amount indicating the life amount until creep rupture due to the progression of creep deformation. The remaining life amount is calculated based on this elapsed life amount, and the remaining life amount until rupture (breakage) is determined based on the creep characteristic diagram and the predicted temperature value of the heating temperature of the cross tie rod 5. For example, if the elapsed life amount exceeds a predetermined threshold value or the remaining life amount becomes smaller than a predetermined amount, it is determined that the life of the cross tie rod 5 is approaching, and a warning is issued. Note that details will be described later, but for example, if the total life amount of the cross tie rod is 1 and the elapsed life amount indicating the elapsed life amount is 2/3, the remaining life amount until rupture (breakage) is 1/3. As the remaining life value approaches zero, the cross tie rod approaches the time of breakage, so for example, a warning such as an alarm or display may be issued when the remaining life value becomes smaller than a predetermined threshold value. Alternatively, a creep characteristic diagram may be used to predict the time of breakage of the cross tie rod based on the remaining life value and the predicted temperature value of the temperature environment in which the cross tie rod will be placed (the temperature to which the cross tie rod will be heated), and the time of breakage may be output.

The temperature measuring means for measuring the temperature of the cross tie rods 5 includes a temperature measuring device such as a thermocouple. Multiple thermocouples are arranged in the furnace length direction on the outer surface of each of the multiple cross tie rods 5 of the coke oven 1. The temperature of each cross tie rod is measured by the thermocouples arranged over the entire length of each cross tie rod 5, and the measured temperature is stored in association with time information indicating the time of measurement.

The temperature is measured over the entire length of each cross tie rod 5 because creep deformation progresses when the temperature of the cross tie rod 5 rises above a certain temperature. One cause of the temperature rising above a certain temperature is heating caused by the combustion of coke oven gas (combustible gas) leaking into the cross tie rod groove 22. Since it is difficult to predict where leakage will occur, it is preferable to measure over the entire length of each cross tie rod 5. If the measurement points are limited, it is also preferable to select and measure points where the temperature is likely to rise, such as near the base of the riser pipe 24, or to increase the interval between the thermocouples.

Instead of using a temperature measuring means to measure the temperature of the cross tie rod 5, a temperature measuring means for measuring the temperature of something other than the cross tie rod 5 may be used to measure the temperature, and the temperature of the cross tie rod 5 may be estimated from the measured temperature. For example, an image of the entire furnace top brick 21 may be taken with a thermo viewer, and the temperature of the furnace top brick 21 above the cross tie rod 5 in the furnace length direction may be determined by image processing.

The temperature of the cross tie rods 5 is estimated from the obtained top brick temperature by heat transfer calculation. The heat transfer calculation is performed using the top brick temperature, the distance from the top brick to the cross tie rods 5, the heat transfer coefficient based on the material, etc. From the photographed image of the top bricks 21, the temperature distribution over the entire length of the multiple cross tie rods 5 located below the top bricks 21 can be confirmed, making it possible to monitor the occurrence of temperature abnormalities due to, for example, gas leakage and ignition from the combustion chamber 3. It is also possible to identify the location where the temperature abnormality occurred and select only the identified cross tie rods 5 to monitor their lifespan.

In a cross tie rod monitoring method or cross tie rod monitoring device that uses a length measuring means to detect the occurrence of creep deformation of the cross tie rod, the length of the cross tie rod 5 is measured and the measured length is stored in association with time information indicating the time of measurement. Then, the timing at which the increase in the measured length value increases is captured, compared to the most recent measured length. For example, as described above, when creep deformation occurs, the increase in the length (total length) of the cross tie rod 5 in the furnace length direction increases. In addition, when progressing from the second stage (steady creep stage) to the third stage (accelerated creep stage), the creep rate suddenly increases, and the increase in the length (total length) of the cross tie rod 5 in the furnace length direction increases. By capturing the change in the increase in the measured length due to creep deformation, the occurrence of creep deformation can be detected. In addition, it is desirable to also store the operating condition history of the coke oven in which the cross tie rod 5 is installed, for example, the operating condition history of the combustion chamber (historical information on the combustion temperature and combustion time in the combustion chamber).

Here, the change in length of the cross tie rod 5 is classified into overall elongation (hereinafter also referred to as total length elongation) and local elongation (hereinafter also referred to as local elongation). The cross tie rod 5 is placed in a high-temperature environment due to radiant heat from the combustion chamber and carbonization chamber located under the furnace top where the cross tie rod 5 is located. The total length elongation is elongation due to thermal expansion of the entire cross tie rod 5 caused by the temperature rise due to the above-mentioned radiant heat. When carbonizing coal, the heating temperature and heating time are controlled to predetermined conditions. Therefore, the temperature change at the location where the cross tie rod 5 is located, that is, the temperature change of the cross tie rod 5, can be predicted based on the coke oven operating conditions (e.g., combustion chamber temperature, etc.), and the amount of length change due to total length elongation can be predicted. Note that, since the temperature to which the cross tie rod 5 is heated due to the temperature rise caused by coal carbonization is usually 400°C or less, elongation due to creep deformation (creep progression) does not occur.

On the other hand, local elongation is elongation due to local thermal expansion and creep deformation of the cross tie rod 5 caused by a temperature rise due to ignition (hereinafter also referred to as direct flame heating) at the gas leak location, for example, heating due to the combustion of coke oven gas (combustible gas) leaking into the cross tie rod groove 22. Direct flame heating raises the temperature to a higher temperature (e.g., 800°C or higher) than the temperature rise due to the above-mentioned radiant heat (about 400°C), so creep deformation progresses to the third stage (accelerated creep stage) in a short period of time. Gas leakage at one or more locations causes length changes (thermal expansion and creep deformation) due to local elongation, and the increase in the measured length value of the cross tie rod 5 is greater than the total length elongation predicted (calculated) based on the coke oven operating conditions (e.g., combustion chamber temperature). Therefore, by monitoring the history of changes in the measured length of the cross tie rod 5, taking into account the total length extension length predicted based on the coke oven operating conditions (e.g., combustion chamber temperature), it is possible to detect the occurrence of localized extension points (direct flame heated points), i.e., the occurrence of creep deformation, which can be taken as a sign of breakage (creep rupture) of the cross tie rod 5.

In addition, a coke oven is provided with many carbonization chambers and combustion chambers, and multiple cross tie rods 5 are arranged in each carbonization chamber and combustion chamber. It is also preferable to monitor the change in length of multiple cross tie rods 5 that are placed under similar operating condition history (temperature history) to capture the occurrence of local elongation. Specifically, if the coke oven operating conditions (e.g., combustion chamber temperature) are approximately the same, the amount of length change due to overall elongation (thermal expansion) of the cross tie rod 5 will be approximately the same. If the amount of length change of a cross tie rod 5 is larger than that of other cross tie rods 5, it is possible to infer that local elongation (elongation due to direct flame heating) has occurred in that cross tie rod 5.

The length of the cross tie rod 5 may be measured continuously or periodically. It is preferable to monitor the history of changes in the measured values measured when the cross tie rod 5 is placed under a specified temperature condition. This is because the amount of change in length due to thermal expansion among the total length elongation is constant, making it easier to capture local elongation. Measurement under a specified temperature condition can be, for example, continuous measurement while the carbonization chamber or combustion chamber is heated at a specified temperature, periodic measurement performed when a specified temperature condition is reached during multiple coal carbonization processes, or periodic measurement performed between the end of coal carbonization and the start of the next coal carbonization. It is sufficient to measure a part of the cross tie rod 5 (for example, the part protruding from the furnace body) or the entire length (total length) to capture the change in the length of the cross tie rod 5.

It is also preferable to use a predicted value calculated based on the actual temperature measured by continuously measuring the temperature of the cross tie rod 5 or the vicinity of the cross tie rod 5 using a thermocouple or thermoviewer as described above, rather than a predicted value calculated based on the coke oven operating conditions (e.g., combustion chamber temperature), as the length change due to full-length elongation. Furthermore, by measuring the temperature over the entire length of the cross tie rod 5 or the vicinity of the cross tie rod 5 and capturing the amount of length change due to local elongation based on the two measured values of the temperature history and the length change history, it is possible to predict the breakage and the time of breakage of the cross tie rod 5 in more detail.

Instead of using a length measuring means to measure the length of the cross tie rod 5, measurements may be performed using a physical quantity measuring means that measures a physical quantity that changes in response to changes in the length of the cross tie rod, and analysis may be performed based on the history of changes in the physical quantity of the cross tie rod. For example, a change in the length (total length) of the cross tie rod 5 in the furnace length direction is reflected in a change in the length of the furnace tightening spring 8 that follows this change.

As shown in Figure 4, the outer end 8a of the furnace locking spring 8 is abutted by a hexagonal nut 9 fixed to the cross tie rod 5. When the overall length of the cross tie rod 5 is increased, the position of the hexagonal nut 9 moves outward in the furnace length direction. The overall length of the furnace locking spring 8 is increased by the amount that the overall length of the cross tie rod 5 is increased. Therefore, by measuring the length of the furnace locking spring 8 instead of measuring the length (total length) of the cross tie rod 5 in the furnace length direction, the progress of creep deformation of the cross tie rod 5 can be grasped.

The length of the furnace tightening spring 8 can be measured directly with a measuring device. Alternatively, a measuring device for indirect measurement can be provided, such as a measuring device using infrared radar to measure the distance between the member that fixes the outer end 8a of the furnace tightening spring 8 and the backstay 4 (point A in Figure 4), or a horseshoe-shaped strain gauge. When the hexagonal nut 9 is tightened, the tightened length can be accumulated and managed as the change in length.

In addition, a change in the length (total length) of the cross tie rod 5 in the furnace length direction is reflected in a change in the magnitude of the load on the furnace locking spring 8. As described above, when the total length of the cross tie rod 5 is increased, the total length of the furnace locking spring 8 also increases accordingly. The load on the furnace locking spring 8 decreases by the amount of increase in its total length. Therefore, instead of measuring the length (total length) of the cross tie rod 5 in the furnace length direction, the progress of creep deformation of the cross tie rod 5 can also be grasped by measuring the load due to the furnace locking spring 8. Note that an example of a measuring means for measuring the load due to the furnace locking spring 8 is a load cell placed between the backstay 4 and the furnace locking spring 8 (point B in Figure 4).

The outline of the coke oven 1 to which the present invention is applied is shown in Figs. 3 and 4. Fig. 3 is an example of a monitoring device that monitors the cross tie rod 5 (STBA 22) using a temperature measurement means. As shown in Fig. 3, the monitoring device 100 for the cross tie rod 5 of this embodiment includes a thermo viewer 13 that takes an image of the furnace top brick 21, an image analysis device 14 that analyzes the image taken by the thermo viewer 13 to determine the temperature of the surface of the furnace top brick 21, and a cross tie rod breakage prediction device 15 that predicts the time of breakage of the cross tie rod 5 based on the temperature of the surface of the furnace top brick 21 determined by the image analysis device 14. The cross tie rod abnormality alarm issued by the cross tie rod breakage prediction device 15 is output to the display panel 17 of the central control room 16 of the coke oven. Note that the cross tie rod abnormality alarm is not limited to one that is recognized visually, and may be an alarm that is recognized audibly.

The cross tie rod breakage prediction device 15 first estimates the temperature over the entire length of the cross tie rod 5 in real time from the furnace brick temperature, which is the temperature of the surface of the furnace brick 21, which is continuously measured by the image analysis device 14, and continuously stores the estimated cross tie rod temperature. When the temperature at each position of the cross tie rod 5 rises above a certain level, creep deformation progresses and finally breaks, so the progress of creep can be estimated using the temperature history. Specifically, based on the measured estimated cross tie rod temperature and the cumulative measurement time at that temperature, the remaining life is estimated using the relationship between temperature and life shown in the creep characteristic diagram. The cross tie rod breakage prediction device 15 estimates the remaining life in real time, and outputs an abnormality alarm if the remaining life falls below a certain threshold, for example.

Here, an example of a method for estimating remaining life using the creep characteristics diagram in Figure 2 is shown below. Table 1 is a table based on Figure 2 that shows the relationship between the temperature of the cross tie rod 5 and the time until the cross tie rod 5 breaks, assuming that the load (stress σ) applied to the cross tie rod 5 is 100 MPa (constant).

Figure 5 is a diagram showing the relationship between temperature and time to fracture based on Table 1 (Figure 2), with the load (stress σ) applied to the cross tie rod 5 set to 100 MPa (constant). The vertical axis of Figure 5 indicates the time to fracture L [hr], and the horizontal axis indicates the temperature Tx [°C]. The points plotted in Figure 5 indicate the time to fracture L [hr] at each temperature from 500°C to 700°C shown in Table 1. The regression line obtained based on these plots is given by the following equation (1).

When the lifespan is set to "1", if the lifespan is L(Tx) hours in an environment of Tx°C, then "1/L(Tx)" of the lifespan will elapse in one hour in an environment of Tx°C. Therefore, the elapsed lifespan, which indicates the amount of lifespan that has elapsed, is the integrated value of the lifespan per hour at the measurement temperature Tx measured by the temperature measurement means, "1/L(Tx)" [hr ^-1 ], and the measured cumulative time H(Tx) [hr] at that measurement temperature Tx. The remaining lifespan F, which indicates the remaining lifespan, is the amount obtained by subtracting the integrated value from the lifespan "1".

For example, if H(Ti) is the cumulative measured time at each temperature Ti from 490°C to 650°C in 1°C increments from the start of coke oven 1 to the present, the remaining life F is expressed by the following formula (2):

Furthermore, based on the remaining life F, the remaining remaining life G(Tx) [hr] in an environment of Tx°C is expressed by the following formula (3).

The calculated remaining life time is output in real time to the display panel 17. Also, when the remaining life amount F or the remaining life time G(Tx) falls below a predetermined threshold value, a cross tie rod abnormality alarm may be output.
Here, there may be cases where the temperature differs depending on the location of one cross tie rod 5. In such a case, the remaining life time calculated for the location with the highest temperature or the remaining life time for the location with the shortest calculated remaining life time may be output.

Since the coke oven 1 is updated approximately every 50 years, it is preferable that the cross tie rod 5 has a lifespan of 50 years or more. As shown in FIG. 2, for example, when the load stress is 100 MPa and the temperature environment is 490°C, the time until breakage is approximately 50 years. Therefore, in the above example, the update period of the coke oven 1 is set to 50 years, and the measurement cumulative time is calculated only for the cases where the temperature of the cross tie rod 5 reaches 490°C or higher. Note that the measurement temperature range is not limited to "490°C or higher". It is desirable to determine the measurement temperature range appropriately based on the update period of the coke oven 1, the load stress of the cross tie rod, and the material.

In addition, for example, in the case of a load stress of 100 MPa, it is also preferable to configure the system to immediately output a cross tie rod abnormality alarm when the estimated temperature of the cross tie rod exceeds 650°C. This is because in a temperature environment of 650°C or higher, creep deformation of the cross tie rod 5 progresses rapidly, resulting in breakage in about 15 hours.

As mentioned above, the load on the cross tie rod 5 is not necessarily constant, but changes in the direction of loosening. If the load is reduced, the remaining life will be extended. Therefore, even if the load is constant, the remaining life is predicted on the stricter side, so the breakage time will be slightly earlier, but there is no problem because a warning will be given before breakage occurs. The remaining life can be calculated more accurately by combining a temperature measurement means for measuring the temperature of the cross tie rod with the load measurement by the load cell placed at the above-mentioned point B. The above-mentioned formula (1) is a function of the temperature Tx only, but if the variables are both the temperature Tx and the load (stress) σ and the cumulative time that satisfies the temperature Tx and the load σ is calculated, the remaining life can be calculated in the same way as the above-mentioned formulas (2) and (3).

According to the present invention, it is possible to predict when the cross tie rod will break (its life span). Since the cross tie rod can be replaced before it breaks based on the predicted breakage time, it is possible to suppress abnormal expansion of the furnace body. By using the cross tie rod until it breaks and then replacing it, it is possible to reduce the cost of equipment and replacement work.

REFERENCE SIGNS LIST 1 Coke oven 2 Carbonization chamber 3 Combustion chamber 4 Backstay 5 Cross tie rod 8 Spring 9 Hexagonal nut 13 Thermoviewer 14 Image analysis device 15 Cross tie rod breakage prediction device 16 Central control room 17 Display panel 21 Furnace top brick 22 Cross tie rod groove 24 Ascending pipe 25 Charging port 35 Pusher side 36 Guide car side 100 Monitoring device X Furnace length direction Y Furnace bed length direction Z Height direction

Claims (9)

A cross tie rod disposed in a coke oven is measured by a temperature measuring means for measuring a temperature of the cross tie rod or a length measuring means for measuring a length of the cross tie rod;
A method for monitoring coke oven cross tie rods, comprising: detecting the occurrence of creep deformation by analyzing based on the temperature history of the cross tie rod accumulated by the measurements ; or detecting signs of breakage of the cross tie rod by analyzing based on the length change history of the cross tie rod and identifying the stage of creep deformation . A cross tie rod disposed in a coke oven is measured by a temperature measuring means for measuring a temperature of the cross tie rod and a length measuring means for measuring a length of the cross tie rod;
A method for monitoring coke oven cross tie rods, comprising: detecting the occurrence of creep deformation by analyzing based on the temperature history of the cross tie rod accumulated by the measurements; and detecting signs of breakage of the cross tie rod by analyzing based on the length change history of the cross tie rod and identifying the stage of creep deformation. A cross tie rod disposed in a coke oven is measured by a temperature measuring means for measuring a temperature of the cross tie rod or a length measuring means for measuring a length of the cross tie rod;
Analyzing the temperature history of the cross tie rod or the length change history of the cross tie rod accumulated by the measurement to detect the occurrence of creep deformation;
A method for monitoring coke oven cross tie rods, comprising predicting an elapsed life, which indicates the progress of the creep deformation, through an analysis based on the temperature history of the cross tie rod. 3. The method for monitoring a coke oven cross tie rod according to claim 1 or 2 , further comprising predicting an elapsed life indicating a progress of the creep deformation by an analysis based on a temperature history of the cross tie rod. 5. The method for monitoring a coke oven cross tie rod according to claim 3 , further comprising the step of predicting a breakage time of the cross tie rod based on the elapsed life. A method for monitoring a coke oven cross tie rod as described in any one of claims 1 to 5 , characterized in that, instead of the temperature measuring means, continuous measurements are performed by a temperature measuring means installed in the coke oven to estimate the temperature of the cross tie rod. Instead of the length measuring means, the measurement is performed by a physical quantity measuring means that measures a physical quantity that changes in response to a change in the length of the cross tie rod,
4. The method for monitoring a coke oven cross tie rod according to claim 1, wherein analysis is performed based on a history of changes in the physical quantity instead of a history of changes in the length of the cross tie rod. A cross tie rod is provided in a coke oven. The cross tie rod breakage prediction device includes a temperature measurement means for measuring a temperature of the cross tie rod and a cross tie rod breakage prediction device for predicting a breakage time of the cross tie rod,
The temperature is measured by the temperature measuring means,
The cross tie rod breakage prediction device is a coke oven cross tie rod monitoring device characterized in that it performs analysis based on the temperature history of the cross tie rod accumulated by measurement to grasp the progress of creep deformation, predicts when the cross tie rod will break, and outputs the predicted time when the cross tie rod will break. A method for measuring a length of a cross tie rod disposed in a coke oven, comprising : a length measuring means for measuring a length of the cross tie rod; and an analysis means for performing an analysis based on a measurement value measured by the length measuring means,
The analysis means grasps the progress of creep deformation based on the length change history of the cross tie rod accumulated by measurement, identifies the stage of creep deformation, and detects and outputs signs of breakage of the cross tie rod in advance. This is a monitoring device for coke oven cross tie rods.

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