CARBONIZATION CHAMBER USABLE PERIOD PREDICTING METHOD AND CARBONIZATION CHAMBER REPAIRING METHOD

Abstract

A carbonization chamber usable period predicting method predicts bulging amount and chamber usable period. The method applies to chambers with oven walls constructed from tongue-and-groove bricks. It includes: measuring oven wall shape to identify bulges from initial hot-state dimensions; performing multiple measurements over time to determine a first regression equation for bulging amounts≤minimum threshold D1 and a second regression equation for bulging amounts≥maximum threshold D2, where D1 and D2 account for brick tolerances and measurement errors; and calculating when bulging will reach a predetermined threshold using the appropriate regression equation to predict usable period.

Description

This application is a National Stage of International Application No. PCT/JP2023/009964 filed Mar. 15, 2023, the entire content of the prior application being incorporated herein by reference.

TECHNICAL FIELD

This application relates to a carbonization chamber usable period predicting method for predicting a usable period of a carbonization chamber with an oven wall bulging inward in an aging coke oven, and also relates to a carbonization chamber repairing method.

BACKGROUND

In recent years, as coke ovens have aged, some of refractories constituting the coke ovens have worn and deformed, and joints between refractories have widened. This causes part of the oven wall of the carbonization chamber, which was flat upon completion of construction of the coke oven, to bulge inward. In the operation of the coke oven, an increase in the amount of bulging of the oven wall of the carbonization chamber causes a pushing clogging, which makes it difficult for coke to be discharged. If a pushing clogging occurs, the amount of coke produced per unit time decreases. If the amount of bulging of part of the oven wall further increases, a ram head of a pushing ram may come into contact with the part, and this will make it difficult for the pushing ram to discharge coke from the carbonization chamber. The contact may cause oven wall refractories to collapse.

To avoid this, the oven wall refractories of the carbonization chamber are to be restacked and repaired before the amount of bulging in the carbonization chamber becomes too large. For the repair, it is necessary to know the location of the inner wall to be repaired and when the repair is to be made. Patent Literature 1 discloses a method that involves identifying a bulging portion of the inner wall of the carbonization chamber and predicting the time when repair of the bulging portion is to be required, that is, the usable period of the carbonization chamber.

CITATION LIST

Patent Literature

• • PTL 1: Japanese Patent No. 6107776

SUMMARY

Technical Problem

Patent Literature 1 states that the relation between the measurement date and time t and the amount of bulging w is expressed by a linear function. However, after acquiring and checking many data sets consisting of the measurement date and time t and the amount of bulging w, it was found that once a certain amount of bulging is reached, the relation between the measurement date and time t and the amount of bulging w no longer fits the linear function, and that the amount of bulging in the carbonization chamber cannot be accurately predicted with the linear function.

This application has been made in view of such a problem in the related art. An object of this application is to provide a carbonization chamber usable period predicting method that can predict the amount of bulging in a carbonization chamber with high accuracy regardless of the amount of bulging and predict the usable period of the carbonization chamber on the basis of the predicted amount of bulging, and to also provide a carbonization chamber repairing method.

Solution to Problem

This application that can solve the problem described above is summarized below.

• • [1] A carbonization chamber usable period predicting method for predicting a usable period of a carbonization chamber of a coke oven, the carbonization chamber having an oven wall constructed by stacking bricks with tongue and groove, includes measuring an oven wall shape of the carbonization chamber with a shape measuring device to identify a bulge bulging inward from an initial position based on hot-state dimensions upon completion of construction of the coke oven; measuring the oven wall shape for the bulge multiple times at different measurement dates and times to determine a first regression equation representing a correspondence between time and the amount of bulging within a range where the amount of bulging is less than or equal to D₁ calculated by the following equation (1) and a second regression equation representing a correspondence between time and the amount of bulging within a range where the amount of bulging is greater than or equal to D₂ calculated by the following equation (2); and calculating a date and time at which the amount of bulging calculated using the first regression equation or the second regression equation reaches a predetermined threshold to predict a usable period of the carbonization chamber,

$\begin{array}{cc}{D}_1=g-\left({\mathrm{dR}}_1+{\mathrm{dL}}_1\right);\mathrm{and}& \left(1\right)\end{array}$ $\begin{array}{cc}{D}_2=g+\left({\mathrm{dR}}_2+{\mathrm{dL}}_2\right),& \left(2\right)\end{array}$

• • where, in the equations (1) and (2), g is a distance (mm) from a side of the brick with tongue and groove to a tongue and groove, dR₁ is a negative manufacturing error value (mm) from the side to the tongue and groove, dR₂ is a positive manufacturing error value (mm) from the side to the tongue and groove, dL₁ is a negative measurement error value (mm) of the shape measuring device, and dL₂ is a positive measurement error value (mm) of the shape measuring device.
  • [2] In the carbonization chamber usable period predicting method according to [1], the threshold is determined on the basis of a gap sd between a ram head of a pushing ram and the initial position of the bulge based on the hot-state dimensions upon completion of construction.
  • [3] A carbonization chamber repairing method includes creating a repair plan for a carbonization chamber on the basis of a usable period predicted using the carbonization chamber usable period predicting method according to [1] or [2]; and repairing the carbonization chamber in accordance with the repair plan.

Advantageous Effects

This application predicts the amount of bulging in the carbonization chamber using a first regression equation and a second regression equation, so that the amount of bulging in the carbonization chamber can be predicted with high accuracy regardless of the amount of bulging in the carbonization chamber. This application predicts the usable period of the carbonization chamber on the basis of the predicted amount of bulging, so that the usable period of the carbonization chamber can be predicted with high accuracy.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view illustrating an example of a coke oven.

FIG. 2 is a horizontal cross-sectional view illustrating a carbonization chamber of the coke oven.

FIG. 3 is a horizontal cross-sectional view illustrating the carbonization chamber of the coke oven.

FIG. 4 is a graph illustrating how the amount of bulging w changes with time.

FIG. 5 is a schematic diagram illustrating a stack of bricks of an oven wall as seen from an end flue.

FIG. 6 is a front view of a brick with tongue and groove constituting the oven wall.

FIG. 7 is a graph indicating, in FIG. 4, a range less than or equal to a minimum value D₁ and a range greater than or equal to a maximum value D₂.

FIG. 8 is a graph illustrating how the amount of bulging w changes with time.

FIG. 9 is a horizontal cross-sectional view of the carbonization chamber of the coke oven.

DESCRIPTION OF EMBODIMENTS

Embodiments of this disclosure will now be described in detail with reference to the drawings. The following embodiments are preferred examples of this application and are not limited by these examples.

FIG. 1 is a perspective view illustrating an example of a coke oven 10. First, the coke oven 10 will be described using FIG. 1. The coke oven 10 includes a regenerative unit 12 constructed by a plurality of regenerative chambers arranged side by side, and a plurality of carbonization chambers 14 and a plurality of combustion chambers 16 disposed on the regenerative unit 12. The carbonization chambers 14 and the combustion chambers 16 are alternately arranged adjacent to each other. A charging car 18 travels over the carbonization chambers 14 and the combustion chambers 16 along a longitudinal direction L of the coke oven 10. A top wall of the carbonization chambers 14 have a plurality of charging holes (not illustrated) arranged along a transverse direction S of the coke oven 10. Coal, which is the raw material for coke, is charged through the charging holes into the carbonization chambers 14. The carbonization chambers 14 each have end flues 14a on both sides thereof. The end flues 14a are each closed by being covered with a removable oven lid (not illustrated). A pusher machine 20 is disposed on the side of one end flue 14a of the carbonization chamber 14, and a guide car 22 is disposed on the side of the other end flue 14a. The pusher machine 20 and the guide car 22 travel along the longitudinal direction L of the oven.

In each carbonization chamber 14, coal is carbonized into a coke cake. To carbonize coal, fuel gas is supplied from each regenerative chamber of the regenerative unit 12 to the combustion chamber 16 for combustion, and the combustion heat is transferred to the adjacent carbonization chamber 14 to heat the carbonization chamber 14. This increases the temperature in the carbonization chamber 14 and coal is carbonized. Upon completion of carbonization of coal, the oven lid is removed, and a pushing ram of the pusher machine 20 is inserted into the carbonization chamber 14. By inserting the pushing ram, the coke cake obtained by carbonization of coal is pushed out of the carbonization chamber 14 and received by the guide car 22 on the opposite side of the pusher machine 20. A quenching car 24 capable of travelling in front of the regenerative unit 12 along the longitudinal direction L of the oven is disposed below the guide car 22, so that the quenching car 24 receives the coke cake from the guide car 22. The quenching car 24 conveys the coke cake to a predetermined location.

The operation of the coke oven 10 involves repetition of pushing the coke cake out of the carbonization chambers 14 and charging coal into the carbonization chambers 14. Repeating this operation causes the oven walls of the carbonization chambers 14 to wear and deform. FIG. 2 is a horizontal cross-sectional view illustrating the carbonization chamber 14 of the coke oven 10. FIG. 2(a) illustrates the carbonization chamber 14 upon completion of construction of the coke oven 10, and FIG. 2(b) illustrates the carbonization chamber 14 with an oven wall 32 deformed and partially bulging inward. The carbonization chamber 14 is formed by a pair of opposite oven walls 32. The oven walls 32 are produced by vertically stacking bricks provided with tongues and grooves.

The coke cake is pushed out by a pushing ram 26. The pushing ram 26 includes a ram head 28 and a ram beam 30 to which the ram head 28 is attached. The pusher machine 20 includes the pushing ram 26 and a pushing ram drive device (not illustrated) connected to the ram beam 30 of the pushing ram 26. When the ram beam 30 is driven by the pushing ram drive device, the ram head 28 is inserted into the carbonization chamber 14, and the coke cake in the carbonization chamber 14 is pushed out of the carbonization chamber 14 by the ram head 28.

In the carbonization chamber 14 illustrated in FIG. 2(a), there is no occurrence of pushing cloggings of the coke cake caused by irregularities in the oven wall 32. In the carbonization chamber 14 illustrated in FIG. 2(b), however, the oven wall 32 has a bulge 34 and the coke cake may come into contact with the bulge 34 when pushed out by the ram head 28. This may increase the resistance encountered during pushing of the coke cake and cause a pushing clogging. The bulge 34 is formed when part of the oven wall 32, which was flat, bulges inward as some of refractories wear and deform or joints between refractories widen, due to aging of the coke oven 10.

If the bulge 34 further bulges inward and the ram head 28 comes into contact with part of the bulge 34, oven wall bricks of the combustion chamber that constitute the oven wall 32 in and around the contact area may collapse or the pushing ram 26 may stop functioning. Since the collapse of oven wall bricks of the combustion chamber, in particular, often takes a long period of time for repair, the contact between the ram head 28 and the bulge 34 is to be avoided.

Therefore, before the amount of bulging of the bulge 34 becomes large enough to cause pushing cloggings of the coke cake or the collapse of oven wall bricks of the combustion chamber, the oven wall 32 of the carbonization chamber 14 is to be repaired, for example, by restacking the refractories. In a carbonization chamber usable period predicting method according to the present embodiment, the usable period of the carbonization chamber 14 is predicted by steps 1 to 4 listed below.

• • 1. The oven wall shape of the carbonization chamber 14 is measured with a shape measuring device to identify a bulge.
  • 2. The oven wall shape of the bulge is measured multiple times at different measurement dates and times to acquire a plurality of data sets, each consisting of the measurement date and time t and the amount of bulging w.
  • 3. A first regression equation representing the correspondence between time and the amount of bulging w within a range where the amount of bulging w is less than or equal to D₁ calculated by the following equation (1), and a second regression equation representing the correspondence between time and the amount of bulging w within a range where the amount of bulging w is greater than or equal to D₂ calculated by the following equation (2), are determined:

$\begin{array}{cc}{D}_1=g-\left({\mathrm{dR}}_1+{\mathrm{dL}}_1\right);\mathrm{and}& \left(1\right)\end{array}$ $\begin{array}{cc}{D}_2=g+\left({\mathrm{dR}}_2+{\mathrm{dL}}_2\right),& \left(2\right)\end{array}$

• • where, in the equations (1) and (2), g is a distance (mm) from a side of a brick with tongue and groove to a tongue and groove, dR₁ is a negative manufacturing error value (mm) from the side of the brick with tongue and groove to the tongue and groove, dR₂ is a positive manufacturing error value (mm) from the side of the brick with tongue and groove to the tongue and groove, dL₁ is a negative measurement error value (mm) of the shape measuring device, and dL₂ is positive measurement error value (mm) of the shape measuring device.
  • 4. A date and time at which the amount of bulging w calculated using the first regression equation or the second regression equation reaches a predetermined threshold is calculated. The period up to this date and time is a usable period of the carbonization chamber 14.

First, a method will be described in which the oven wall shape of the carbonization chamber 14 is measured with a shape measuring device to identify a bulge. FIG. 3 is a horizontal cross-sectional view illustrating the carbonization chamber 14 of the coke oven 10. The oven wall shape of the carbonization chamber 14 is measured under hot conditions, for example, by a laser-based three-dimensional shape measuring device 36. Note that the laser-based three-dimensional shape measuring device 36 is an exemplary shape measuring device that measures the oven wall shape of the carbonization chamber 14 under hot conditions. The laser-based three-dimensional shape measuring device 36 is installed in front of an end flue 14a on the side of the carbonization chamber 14 from which the coke cake is discharged. The laser-based three-dimensional shape measuring device 36 measures the oven wall shape of the carbonization chamber 14 as a point cloud by obliquely irradiating the oven wall 32 with laser through a laser irradiation hole and receiving reflected light from the oven wall 32 at a detection hole. The hot-state dimensions of the oven wall shape of the carbonization chamber 14 can thus be acquired.

Although the oven wall shapes on the right and left sides of the carbonization chamber 14 may be simultaneously measured using the laser-based three-dimensional shape measuring device 36, it is preferable to separately measure the oven wall shapes on the right and left sides of the carbonization chamber 14. The carbonization chamber 14 is about 6 m high, about 400 mm wide, and about 16 m deep on the upper side, and the end flue 14a has a narrow, elongated structure about 400 mm wide and about 6 m high. In irradiation of laser from outside the carbonization chamber 14, the incident angle of laser on the oven wall 32 is shallow if the oven wall shapes on both the right and left sides are to be measured simultaneously. When laser is incident at such a shallow angle, if the oven wall 32 bulges inward, a shaded area that laser cannot reach may be created at the back of the bulging portion and the oven wall shape cannot be measured. On the other hand, when the oven wall shapes on the right and left sides are separately measured, the incident angle of laser on the oven wall 32 can be increased, so that the oven wall shape can be measured even if the oven wall 32 bulges inward.

The right and left inner wall shape data measured by the laser-based three-dimensional shape measuring device 36 may be evaluated separately, or these two pieces of inner wall shape data may be combined on the basis of a reference object around the carbonization chamber 14 and evaluated as a single piece of composite oven wall shape data. The oven wall shape of the carbonization chamber 14 in the coke oven 10 can thus be measured by using the laser-based three-dimensional shape measuring device 36.

Referring back to FIG. 2(b), the oven wall shape of the carbonization chamber 14 is measured using the laser-based three-dimensional shape measuring device 36, and oven wall shape data acquired by this measurement is compared with hot-state measurement data of the carbonization chamber 14 acquired immediately after completion of construction to obtain differential shape data. A portion of the differential shape data bulging inward from an initial position based on the hot-state dimensions obtained upon completion of construction of the coke oven 10 is the bulge 34. The position of the bulge 34 can thus be identified.

If there are a plurality of bulges that bulge inward from the initial position, it is preferable to identify a portion with the largest amount of bulging w as the bulge. This is because the amount of bulging w of a bulge with the largest amount of bulging w is considered to increase most rapidly. The position of the bulge simply needs to be identified at least once before predicting the usable period of the carbonization chamber 14. However, after the position of the bulge that bulges the most is initially identified, the most bulging area may change gradually. In this case, the position of another bulge may be identified instead of, or in addition to, the bulge initially identified.

Next, the oven wall shape is measured multiple times at different measurement dates and times to acquire a plurality of data sets, each consisting of the measurement date and time t and the amount of bulging w of the bulge identified. A dotted line in FIG. 2(b) indicates the initial position of the oven wall 32 based on the hot-state dimensions obtained upon completion of construction of the coke oven 10, and a black dot on the dotted line indicates the initial position of the bulge 34 based on the hot-state dimensions obtained upon completion of construction of the coke oven 10. A solid line in FIG. 2(b) is a line parallel with the dotted line and tangent to the most bulging area of the bulge 34. The initial position of the bulge 34 is a point at which a line extending perpendicularly from the most bulging area of the bulge 34 to the dotted line intersects the dotted line. The amount of bulging w is the distance from the initial position of the bulge 34 to the dotted line. As described above, once the bulge 34 is identified, the initial position of the bulge 34 is also identified. Therefore, the amount of bulging w of the bulge 34 can be determined by acquiring the oven wall shape data measured by the laser-based three-dimensional shape measuring device 36.

Although the measurement interval of the amount of bulging w is not particularly limited, it is preferable to regularly measure the amount of bulging w every few days, weeks, or months to check how the amount of bulging w changes with time. For example, during the operation of the coke oven 10, the amount of bulging w is unlikely to significantly change over six hours or one day. However, the amount of bulging w may change, for example, over a few days. Therefore, it is preferable to define the period of measurement as two weeks or one month, and measure the amount of bulging w at each period of measurement defined. For a carbonization chamber where the amount of bulging w is large, the measurement interval may be shortened to, for example, one week. This can improve accuracy in predicting the amount of bulging w using a regression equation. Specifically, if the difference between the distance from the initial position of the bulge 34 to the ram head 28 and the amount of bulging w is less than or equal to 10 mm, it is preferable to increase the frequency of measuring the amount of bulging w.

FIG. 4 is a graph illustrating how the amount of bulging w changes with time. In FIG. 4, the horizontal axis represents year/month, and the vertical axis represents the amount of bulging w (mm). The graph illustrated in FIG. 4 is a plot of 16 data sets, each consisting of the measurement date and time t and the amount of bulging w, acquired by measuring the oven wall shape of the carbonization chamber of the coke oven 16 times with the laser-based three-dimensional shape measuring device at different measurement dates and times, and using the measurement data. It can be seen from FIG. 4 that the amount of bulging w per unit time changes significantly when the amount of bulging is in the range of 30 mm to 40 mm. This means that with a regression equation determined from data points in the range where the amount of bulging is small, the amount of bulging w in the range where the amount of bulging is large cannot be correctly predicted.

FIG. 5 is a schematic diagram illustrating a stack of bricks of the oven wall 32 as seen from the end flue. FIG. 5(a) illustrates the oven wall 32 before it bulges inward (toward the carbonization chamber), and FIG. 5(b) illustrates the oven wall 32 after it bulges inward (toward the carbonization chamber). The oven wall 32 of the carbonization chamber 14 is manufactured by vertically stacking bricks with tongue and groove 40. The bricks with tongue and groove 40 are supported by binder bricks (not illustrated).

Before the oven wall 32 bulges inward, the weight of each brick with tongue and groove 40 is supported by the brick with tongue and groove 40 located below it, as illustrated in FIG. 5(a). However, it was found that when the amount of bulging w of the oven wall 32 becomes greater than or equal to a predetermined amount, the bricks with tongue and groove 40 are no longer supported by the binder bricks and the bricks with tongue and groove 40 further bulge inward due to their weight, as illustrated in FIG. 5(b). As a result of checking the amount of bulging w caused by the weight of the bricks with tongue and groove 40, it was found that when the amount of bulging w becomes greater than or equal to the distance from a tongue and groove 42 of the brick with tongue and groove 40 to the side of the brick, the bricks with tongue and groove 40 further bulge inward due to their weight.

The distance from the tongue and groove 42 of the brick with tongue and groove 40 to the side of the brick has a manufacturing error. Therefore, the minimum value D₁ of the distance from the brick side to the tongue and groove 42 including the manufacturing error is g-dR₁, where g is the distance from the side of the brick with tongue and groove 40 to the tongue and groove 42, and dR₁ is a negative manufacturing error value from the side to the tongue and groove 42. Similarly, the maximum value D₂ of the distance from the brick side to the tongue and groove 42 including the manufacturing error is g+dR₂, where g is the distance from the side of the brick with tongue and groove 40 to the tongue and groove 42, and dR₂ is a positive manufacturing error value from the side to the tongue and groove 42.

Also, a measurement error occurs in measuring the oven wall shape using a shape measuring machine. Therefore, the minimum value D₁ and the maximum value D₂ of the distance g from the side of the brick with tongue and groove 40 to the tongue and groove 42 are g−(dR₁+dL₁) and g+ (dR₂+dL₂), respectively, where dL₁ is a negative measurement error value, and dL₂ is a positive measurement error value.

FIG. 6 is a front view of the brick with tongue and groove 40 constituting the oven wall. In the present embodiment, the distance from the tongue and groove 42 to the side of the brick with tongue and groove 40 is 33 mm, a manufacturing error in this area of the brick with tongue and groove 40 is ±2 mm, and a measurement error in measuring the oven wall shape using the laser-based three-dimensional shape measuring device is ±5 mm. Therefore, in the oven wall 32, the minimum value D₁ of the distance g from the side of the brick with tongue and groove 40 to the tongue and groove 42 is 26 mm, and the maximum value D₂ of the distance g from the brick side to the tongue and groove 42 is 40 mm.

FIG. 7 is a graph indicating, in FIG. 4, a range less than or equal to the minimum value D₁ (26 mm) and a range greater than or equal to the maximum value D₂ (40 mm). In FIG. 7, data points within the range less than or equal to the minimum value D₁ are indicated in white, data points within the range greater than or equal to the maximum value D₂ are indicated in black, and data points within the range greater than the minimum value D₁ and less than maximum value D₂ are indicated in gray. The regression line of first regression equation determined from the data points within the range less than or equal to the minimum value D₁ is indicated by a solid line, and the regression line of the second regression equation determined from the data points within the range greater than or equal to the maximum value D₂ is indicated by a dotted line.

The data points of the measurement date and time t versus the amount of bulging w were divided into the range less than or equal to the minimum value D₁ and the range greater than or equal to the maximum value D₂, and the first regression equation and the second regression equation were determined using the data points in each range. As a result, the regression lines representing the first regression equation and the second regression equation were each located near the data points within the corresponding range, and the first regression equation and the second regression equation were regression equations each having a high correlation with the data points within the range. This result shows that the prior art, which predicts the amount of bulging w using one regression equation, cannot predict the amount of bulging w with high accuracy in the range where the amount of bulging of the oven wall 32 is large, whereas the carbonization chamber usable period predicting method according to the present embodiment predicts the amount of bulging w using the first regression equation and the second regression equation, so as to predict the amount of bulging w of the oven wall 32 with high accuracy, regardless of the amount of bulging of the oven wall 32.

FIG. 8 is a graph illustrating how the amount of bulging w in other carbonization chambers changes with time. FIGS. 8(a) to (c) illustrate data points of the measurement date and time t versus the amount of bulging w acquired by measuring the oven wall shapes of three carbonization chambers that have oven walls constructed by the bricks with tongue and groove 40 illustrated in FIG. 6 but are different from the carbonization chamber for which the amount of bulging is illustrated in FIG. 7.

As illustrated in FIGS. 8(a) to (c), in the other three carbonization chambers, significant changes were also observed in the range from the minimum value D₁ to the maximum value D₂, similarly to FIG. 7. Therefore, as in FIG. 7, the data points were divided into the range less than or equal to the minimum value D₁ and the range greater than or equal to the maximum value D₂, and the first regression equation and the second regression equation were determined using the data points in each range. Thus, the first regression equation and the second regression equation were regression equations each having a high correlation with the data points within the range.

These results found that for the carbonization chamber 14 having the oven wall 32 constructed by the bricks with tongue and groove 40, the amount of bulging w can be predicted with high accuracy, regardless of the amount of bulging, by determining the first regression equation representing the correspondence between time and the amount of bulging w within the range where the amount of bulging is less than or equal to the minimum value D₁ calculated by the following equation (1), and the second regression equation representing the correspondence between time and the amount of bulging w within the range where the amount of bulging is greater than or equal to the maximum value D₂ calculated by the following equation (2), and predicting the amount of bulging w using the regression equations:

$\begin{array}{cc}{D}_1=g-\left({\mathrm{dR}}_1+{\mathrm{dL}}_1\right);\mathrm{and}& \left(1\right)\end{array}$ $\begin{array}{cc}{D}_2=g+\left({\mathrm{dR}}_2+{\mathrm{dL}}_2\right),& \left(2\right)\end{array}$

• • where, in the equations (1) and (2), g is a distance (mm) from a side of a brick to a tongue and groove, dR₁ is a negative manufacturing error value (mm) from the side of the brick to the tongue and groove, dR₂ is a positive manufacturing error value (mm) from the side of the brick to the tongue and groove, dL₁ is a negative measurement error value (mm) of the shape measuring device, and dL₂ is a positive measurement error value (mm) of the shape measuring device.

Next, a method for predicting a usable period of the carbonization chamber 14 using the first regression equation or the second regression equation will be described. When the amount of bulging w of the oven wall 32 increases, the coke cake comes into contact with the bulge, which increases resistance encountered during pushing of the coke cake and causes a pushing clogging. If the bulge 34 comes into contact with the ram head 28, the oven wall bricks of the combustion chamber collapse. Therefore, an experiment or the like is first performed to determine the amount of bulging w of the oven wall 32 at which a pushing clogging or collapse of the oven wall bricks of the combustion chamber occurs. This amount of bulging w is determined as a threshold in advance, and the date and time at which the amount of bulging w reaches the threshold is calculated by using the first regression equation if the threshold is less than or equal to the minimum value D₁ and by using the second regression equation if the threshold is greater than or equal to the maximum value D₂. These date and time indicate the usable period of the carbonization chamber 14. The usable period of the carbonization chamber 14 can thus be predicted using the first regression equation or the second regression equation.

The threshold for the amount of bulging w may be determined on the basis of a gap sd between the initial position of the bulge 34 and the ram head 28 of the pushing ram 26. FIG. 9 is a horizontal cross-sectional view of the carbonization chamber of the coke oven. The gap sd will now be explained using FIG. 9.

The gap sd is a gap between the ram head 28 and the initial position of the bulge 34 at a position where the ram head 28 is closest to the bulge 34. A dot-and-dash line in FIG. 9 indicates the side position of the ram head 28, and a black dot on a dotted line indicates the initial position of the bulge 34 based on the hot-state dimensions obtained upon completion of construction of the coke oven 10. The gap sd is the distance from the initial position of the bulge 34 to the dot-and-dash line.

Once the position of the bulge 34 is identified by measuring the oven wall shape, the initial position of the bulge 34 is also identified. The side position of the ram head 28 may be determined by actual measurement of the side position of the ram head 28 moving through the carbonization chamber 14, or by calculation from the dimensions of the ram head 28 on the assumption that the center of the ram head 28 passes in the center of the carbonization chamber 14. The gap sd between the initial position of the bulge 34 and the ram head 28 is thus determined from the initial position of the bulge 34 and the side position determined by the actual measurement or calculation.

As described above, if the amount of bulging w of the bulge 34 exceeds the gap sd, the bulge 34 comes into contact with the ram head 28 and this increases the possibility that the oven wall bricks of the combustion chamber will collapse. Therefore, for example, a value obtained by multiplying the gap sd by a predetermined safety factor may be determined to be the threshold. By thus determining the threshold on the basis of the gap sd, it is possible to reduce the possibility of contact between the bulge 34 and the ram head 28 and the collapse of the oven wall bricks of the combustion chamber.

As described above, in the carbonization chamber usable period predicting method according to the present embodiment, the amount of bulging w is predicted using the first regression equation and the second regression equation. This makes it possible to predict the amount of bulging w of the oven wall with high accuracy regardless of the amount of bulging of the oven wall 32, and predict the usable period of the carbonization chamber 14 with high accuracy using the amount of bulging w. By predicting the usable period of the carbonization chamber 14, the carbonization chamber can be repaired at appropriate time. By repairing the carbonization chamber at appropriate time, it is possible to use the carbonization chamber 14 to its full extent while reducing the occurrence of pushing cloggings in the carbonization chamber 14 and collapse of the oven wall.

A repair plan for the carbonization chamber may be created on the basis of the usable period of the carbonization chamber predicted by the carbonization chamber usable period predicting method according to the present embodiment. Specifically, a repair plan for repairing the oven wall of the carbonization chamber is created before the usable period of the carbonization chamber expires. By thus predicting the usable period of the carbonization chamber before creating a repair plan, the creation of the repair plan for the carbonization chamber is facilitated.

Claims

1. A carbonization chamber usable period predicting method for predicting a usable period of a carbonization chamber of a coke oven, the carbonization chamber having an oven wall constructed by stacking bricks with tongue and groove, the method comprising: D 1 = g - ( dR 1 + dL 1 ); and ( 1 ) D 2 = g + ( dR 2 + dL 2 ), ( 2 )

measuring an oven wall shape of the carbonization chamber with a shape measuring device to identify a bulge bulging inward from an initial position based on hot-state dimensions upon completion of construction of the coke oven;

measuring the oven wall shape for the bulge multiple times at different measurement dates and times to determine a first regression equation representing a correspondence between time and the amount of bulging within a range where the amount of bulging is less than or equal to D1 calculated by the following equation (1) and a second regression equation representing a correspondence between time and the amount of bulging within a range where the amount of bulging is greater than or equal to D2 calculated by the following equation (2); and

calculating a date and time at which the amount of bulging calculated using the first regression equation or the second regression equation reaches a predetermined threshold to predict a usable period of the carbonization chamber,

where, in the equations (1) and (2), g is a distance (mm) from a side of the brick with tongue and groove to a tongue and groove, dR1 is a negative manufacturing error value (mm) from the side to the tongue and groove, dR2 is a positive manufacturing error value (mm) from the side to the tongue and groove, dL1 is a negative measurement error value (mm) of the shape measuring device, and dL2 is a positive measurement error value (mm) of the shape measuring device.

2. The carbonization chamber usable period predicting method according to claim 1, wherein the threshold is determined on the basis of a gap sd between a ram head of a pushing ram and the initial position of the bulge based on the hot-state dimensions upon completion of construction.

3. A carbonization chamber repairing method comprising:

creating a repair plan for a carbonization chamber on the basis of a usable period predicted using the carbonization chamber usable period predicting method according to claim 1; and

repairing the carbonization chamber in accordance with the repair plan.

4. A carbonization chamber repairing method comprising:

creating a repair plan for a carbonization chamber on the basis of a usable period predicted using the carbonization chamber usable period predicting method according to claim 2; and

repairing the carbonization chamber in accordance with the repair plan.