Masonry structure of coke oven

Abstract

To provide a masonry structure of a coke oven capable of suppressing communication between a combustion chamber and a carbonization chamber caused by cracks or chipping of bricks, thereby preventing gas generated from coal being carbonized in the carbonization chamber from flowing into the combustion chamber and suppressing occurrence of incomplete combustion.SOLUTION: A masonry structure of a coke oven comprises laufer wall bricks constituting a laufer wall partitioning a carbonization chamber and a combustion chamber, binder wall bricks constituting a binder wall partitioning combustion chambers, and front bricks placed at an oven port at an end part in a furnace length direction of the combustion chamber. These are stacked in multiple stages. The laufer wall bricks and the binder wall bricks have a configuration comprising predetermined first bricks, the front bricks have a configuration comprising predetermined second bricks or have a configuration comprising the first bricks and the second bricks, and a deviation width between a vertical joint between the second bricks at a predetermined stage and the first bricks adjacent thereto and a vertical joint at another stage is 16.9% or more and 21.5% or less of a height of the stage.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to the brick masonry construction of coke ovens. [Background technology]

[0002] A coke oven has a structure called a furnace battery, in which multiple coking chambers, where raw coal is charged, and combustion chambers, where fuel gas is burned with air, are arranged alternately across the width of the oven. Combustion heat from the combustion chamber is indirectly supplied to the coking chamber through the oven wall between the coking chamber and the combustion chamber, i.e., heat is supplied in the form of heat transfer, and the coal charged in the coking chamber is heated and carbonized to produce coke. The coking chamber and the combustion chamber are mainly separated by a stretcher wall. The combustion chamber is divided into several chambers along the length of the furnace, and one chamber (combustion chamber) is separated from the next by a binter wall. The stretcher wall is made of stretcher wall bricks, and the binter wall is made of binter wall bricks. Silica bricks are often used for the stretcher wall bricks and binter wall bricks. Furnace covers are placed at both ends of the coking chamber, and these ends are called the kiln mouth. The wall of the kiln mouth is made of front bricks, which are often made of chamotte or high-alumina bricks. There are also types that use silica bricks. A coke oven has a brick masonry structure in which these bricks are stacked in multiple layers.

[0003] Coke ovens are heated by combustion in the combustion chamber of the oven battery, but the oven mouth cools when the oven cover is removed. Therefore, the front bricks and their surroundings are repeatedly heated and cooled when the oven cover is removed. Because multiple types of bricks are used for the front bricks and their surroundings, differences in the linear expansion coefficients of the bricks due to temperature changes can easily cause cracks and chips due to expansion and contraction. In particular, if these vertical joints are continuous across multiple levels, cracks and chips are likely to occur in concentrated areas along these vertical joints due to expansion and contraction caused by heating and cooling, or collisions with adjacent bricks. This can lead to holes connecting the combustion chamber and the coking chamber.

[0004] The silica bricks that make up the brick masonry structure have a linear expansion coefficient that is nearly zero and stable with temperature increases and decreases at high temperatures above 800°C (especially between 900°C and 1200°C), but they begin to expand with temperature decreases below 800°C.On the other hand, the chamotte and high-alumina bricks that make up the kiln mouth experience linear expansion with temperature increases and decreases regardless of the temperature range. As a result, at the vertical joints (vertical joints) at the boundary between the chamotte or high-alumina bricks that make up the front bricks at the kiln mouth and the silica bricks that make up the furnace interior, forces in the direction of separation or collision occur due to the difference in the change in linear expansion coefficient of the two bricks caused by temperature changes, which can result in cracks, chips, or in some cases, holes.

[0005] If a hole occurs between the combustion chamber and the carbonization chamber, gas generated from the coal being dry-distilled in the carbonization chamber will flow into the combustion chamber, hindering good combustion in the combustion chamber and resulting in incomplete combustion. One solution to this problem is to adjust the amount of air or gas supplied to the combustion chamber to ensure complete combustion, but this would also adjust the amount of air or gas supplied to the combustion chamber without holes, which could result in incomplete combustion.Incomplete combustion could result in black smoke coming out of the chimney, which is environmentally undesirable. For this reason, cracks and the like are repaired by semi-dry spray repair or thermite reaction ceramic spray repair at the locations where cracks and the like have occurred, and measures are taken to prevent communication between the combustion chamber and the carbonization chamber.

[0006] Furthermore, it has been proposed to maintain the airtightness of the combustion chamber and the coking chamber by using bricks with special shapes as shown in Patent Document 1. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2022-154188 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the method described in Patent Document 1 requires the use of specially shaped bricks in addition to the ordinary bricks used in coke ovens, which requires the preparation of specially shaped bricks, and tends to be less efficient. Furthermore, repairs using spray or thermal spraying do not prevent cracks and the like from occurring in the bricks, and are therefore hardly a fundamental solution.

[0009] This invention was made to solve the above problems. That is, the object is to prevent the combustion chamber and the coking chamber from communicating with each other due to cracks or chips in the bricks, thereby preventing gas generated from coal being carbonized in the coking chamber from flowing into the combustion chamber and suppressing incomplete combustion. [Means for solving the problem]

[0010] As a result of extensive research into solving the above-mentioned problems, the inventors discovered that by keeping the misalignment width of each row of vertical joints between a specified second brick and a specified first brick within a specified range, cracks and chips in the bricks are less likely to occur, leading to the invention.

[0011] That is, the gist of the present invention is as follows. [1] A brick masonry structure of a coke oven, which is composed of stretcher wall bricks that form the stretcher wall separating the coke oven chamber from the combustion chamber, binder wall bricks that form the binder wall separating the combustion chamber from the other combustion chamber, and front bricks that are arranged at the kiln mouth at the end of the combustion chamber in the furnace length direction, stacked in multiple layers, wherein the stretcher wall bricks and the binder wall bricks are composed of first bricks, and the front bricks are composed of second bricks or first bricks and second bricks, and the first bricks have a linear expansion coefficient that changes by 0.09% or more and 0.15% or less when the temperature around the brick rises by 200°C when the temperature around the brick rises from 400°C to 600°C, and the linear expansion coefficient of the first bricks is 0.09% or more and 0.15% or less when the temperature around the brick rises by 200°C when the temperature around the brick rises from 600°C to 800°C. the change in the coefficient of linear expansion of the first brick when the temperature rises by 200°C when the temperature rises from 800°C to 1200°C is 0.05% or more and 0.11% or less, and the change in the coefficient of linear expansion of the first brick when the temperature rises by 200°C when the temperature rises from 800°C to 1200°C is 0.05% or less, the second brick is a brick whose change in the coefficient of linear expansion of the second brick when the temperature rises by 200°C when the temperature around the second brick rises from 400°C to 1200°C is 0.10% or more and 0.15% or less, and the deviation between the vertical joint between the second brick and the adjacent first brick in a given row and the vertical joint in another row is 16.9% or more and 21.5% or less of the height of the row. [2] The brick masonry structure of a coke oven described in [1], wherein the first brick is made of silica brick and the second brick is made of chamotte or high-alumina brick. [Effects of the Invention]

[0012] According to this invention, by setting the offset between the vertical joint between the second brick and the adjacent first brick in a given row and the vertical joint in another row within a predetermined ratio of the row height, the vertical joint between the second brick and the adjacent first brick can be prevented from continuing across multiple rows, and the vertical joints can be offset in each row. Since the vertical joints can be prevented from continuing across multiple rows, cracks and chips in the bricks are less likely to occur. Even if cracks or chips do occur, they are prevented from growing larger, and holes connecting the combustion chamber and the coke chamber are less likely to form. This prevents gas generated from the coal being carbonized in the coke chamber from flowing into the combustion chamber, suppressing incomplete combustion and, as a result, suppressing black smoke from the chimney. [Brief explanation of the drawings]

[0013] [Figure 1] (a) is a plan view showing an example of a combustion chamber of a coke oven according to the present invention; (b) is a side view of (a); [Figure 2] FIG. 10 is a side view showing an example of a combustion chamber of another coke oven according to the present invention. [Figure 3] Photographs showing the results of Example 1 [Figure 4(a)] Photograph showing the results of Comparative Example 1 (after 11 years) [Figure 4(b)] Photograph showing the results of Comparative Example 1 (after 32 years) [Figure 5] Photograph showing the results of Comparative Example 2 DETAILED DESCRIPTION OF THE INVENTION

[0014] The brick masonry structure of the coke oven according to the present invention has a structure in which a brick structure made up of stretcher wall bricks that form the stretcher wall separating the coke oven chamber from the combustion chamber, binder wall bricks that form the binder wall separating the combustion chamber from the other combustion chamber, and front bricks that are arranged at the kiln mouth at the end of the combustion chamber in the furnace length direction are stacked in multiple layers.

[0015] [Combustion chamber] The combustion chamber will be described with reference to the plan view of the combustion chamber shown in FIG. 1(a). The combustion chamber 11 shown in Figure 1(a) has its left and right sides in the furnace length direction and its top and bottom in the furnace width direction, with kiln mouths located at both ends in the furnace length direction (the left ends in Figure 1(a) because the right side is omitted). Furnace covers (not shown) are located on the outside of these kiln mouths at both ends. In addition, combustion chambers 11 and carbonization chambers 12 with heat transfer surfaces are arranged alternately in the furnace width direction.

[0016] The wall of the combustion chamber 11 where the kiln mouth at the end of the furnace length is located is made of bricks called front bricks 13, the combustion chamber 11 and the carbonization chamber 12 are separated by a stretcher wall 14, and the combustion chamber 11 and the adjacent combustion chamber 11 are separated by binder wall bricks 15 that make up the binder wall. The stretcher wall 14 is mainly composed of stretcher wall bricks 16 that separate the coke chamber from the combustion chamber. Depending on the brick masonry structure of the coke oven, in addition to the stretcher wall bricks 16, end protrusions 15a' of binder wall bricks 15 (15a) may also be arranged, as shown in Figure 1(b).

[0017] [Binder Wall Bricks] The binder wall bricks 15 may be, for example, binder wall bricks 15a having end protrusions 15a' at both ends as shown in Fig. 1(a), binder wall bricks 15b having no end protrusions 15a' at both ends, or bricks (not shown) in which a stretcher wall brick is integrated with one or both ends of the binder wall brick. These may be used as appropriate. 1(a) and 1(b), in one row, the binder wall bricks 15a and binder wall bricks 15b are arranged alternately as shown in FIG. 1(a). In addition, in a masonry structure in which binder wall bricks are stacked in multiple rows, the binder wall bricks 15a and binder wall bricks 15b are stacked alternately. This is clear from the fact that the end protrusions 15a' of the binder wall bricks 15a appear every other row in FIG. 1(b).

[0018] As shown in Figure 1(a), the binder wall brick 15 has a cavity 15c in its center. In the case of a single-type furnace, this is an air supply hole for vertical combustion. The air sent to this cavity 15c is sent to the combustion chamber 11 through a vent hole (not shown) provided in the binder wall brick 15 between the combustion chamber 11 and the cavity 15c of the binder wall brick 15, contributing to combustion. In addition, a burner hole 15d is provided on the underside of the combustion chamber 11. Although not shown, air heated in the lower heat storage chamber mixes with flammable gas from the burner hole, causing spontaneous ignition and combustion. In the case of a double-type furnace, the burner hole 15d is not used, and the cavity 15c is used as a pair of flammable gas supply hole and air supply hole. Although not shown, the front bricks 13, the reufer wall bricks 16, and the binder wall bricks 15a and 15b have grooves in the tops of them, and the bottoms of these bricks have grooves in the bottoms of them, and these grooves fit together to keep the brick masonry structure of this invention strong and stable. Furthermore, mortar is generally used as an adhesive in the grooves.

[0019] [Brick characteristics] The stretcher wall bricks 16 and binder wall bricks 15 are configured to be made up of first bricks 13b, which will be described later. The front bricks 13 may be configured to be made up of second bricks 13a, which will be described later, as shown in Fig. 2, or may be configured to be made up of second bricks 13a and first bricks 13b, as shown in Figs. 1(a) and 1(b).

[0020] The first brick is a brick in which the change in linear expansion coefficient of the brick when the temperature around the brick rises by 200°C from 400°C to 600°C (hereinafter simply referred to as "change in linear expansion coefficient") is 0.09% to 0.15%, the change in linear expansion coefficient when the temperature rises from 600°C to 800°C is 0.05% to 0.11%, and the change in linear expansion coefficient of the brick when the temperature rises by 200°C from 800°C to 1200°C (change in linear expansion coefficient) is 0% to 0.05%. Therefore, the linear expansion coefficient of the first brick increases with increasing temperature up to around 800°C, but at high temperatures above 800°C (particularly 900°C to 1200°C), the change in linear expansion coefficient with increasing temperature is almost zero. Furthermore, even if temperature changes occur at high temperatures above 800°C (especially between 900°C and 1200°C), there is almost no expansion or contraction. At 200°C to 400°C, the change in linear expansion coefficient is between 0.1% and 0.15%, which is higher than the change in linear expansion coefficient when the temperature rises from 400°C to 800°C. An example of the first brick is a firebrick such as a silica brick.

[0021] The second brick is a brick whose change in linear expansion coefficient (linear expansion coefficient change) when the temperature around the brick rises by 200°C from 400°C to 1200°C is 0.10% or more and 0.15% or less. This second brick has the above change in linear expansion coefficient within the range of 200°C to 1200°C. In other words, within the range of 200°C to 1200°C, the linear expansion coefficient changes and expansion and contraction occur in response to temperature changes.

[0022] The first brick has different linear expansion coefficient changes from 200°C to 400°C, 400°C to 600°C, 600°C to 800°C, and 800°C to 1200°C, so a graph showing the relationship between linear expansion coefficient and temperature will be a broken line with bends near 400°C, 600°C, and 800°C. However, the second brick has almost no change in linear expansion coefficient change from 200°C to 1200°C, so the graph showing the relationship between linear expansion coefficient and temperature will be a nearly straight line with some bends.

[0023] Examples of the second brick include firebricks such as chamotte bricks and high-alumina bricks. Chamotte bricks are firebricks made from clinker, which is made by firing natural clay materials at high temperatures, and have an alumina content of less than 45%. High-alumina bricks are firebricks with an alumina content of 45% or more.

[0024] [Front brick] Incidentally, when the front bricks 13 at the kiln mouth are configured to consist of second bricks 13a as shown in FIG. 2, the entire kiln mouth will expand and contract due to temperature changes. As shown in Figure 1(b), the front brick 13 that reduces the degree of expansion and contraction of the second brick can be configured to consist of second bricks 13a and first bricks 13b, with the first bricks 13b arranged on the side that contacts the inside of the furnace (the carbonization chamber 11 and the combustion chamber 12). Since the first bricks hardly expand or contract due to temperature changes at 800°C or higher, by combining the second bricks 13a and the first bricks 13b, the proportion of the second bricks 13a used in the kiln opening can be reduced, and the degree of expansion and contraction of the front bricks 13 in the kiln opening due to heating and cooling caused by removing and attaching the furnace cover, especially at temperatures above 800°C, can be reduced.

[0025] As long as the object of the present invention is not impaired, the first bricks 13b may be disposed on the front bricks 13 other than the side surfaces thereof that contact the inside of the furnace (the coking chamber 11 and the combustion chamber 12). Incidentally, the front brick section that connects to the stretcher wall 14 is arranged with bricks over the entire length of the coke oven, so the expansion and contraction of the bricks directly affects both ends of the coke oven. In this case, protective metal fittings (not shown) are attached to the outer part of the front brick that connects to the stretcher wall 14, and steel members called backstays (not shown) are placed on the outside, with a tightening mechanism (not shown) built in between. These structures cushion the expansion and contraction of the brick structure.

[0026] [Gap width of vertical joint (specific vertical joint) between the second brick and the adjacent first brick] Incidentally, as described above, the behavior of bricks during coke oven operation is such that there is a large difference in the amount of change in linear expansion coefficient between the second brick and the first brick, particularly at high temperatures above 800°C and low temperatures below 400°C. This means that forces in the direction of separation or collision are generated at the vertical joints where these two types of bricks adjoin (i.e., the vertical joint between the second brick and the adjacent first brick; hereinafter, this may be referred to as the "specific vertical joint"), which may result in cracks, chips, etc. Specific vertical joints at which cracks or chips may occur include the vertical joint between the second brick 13a in the front brick 13 and the adjacent first brick 13b, as shown in Figure 1(b), and the vertical joint between the second brick 13a constituting the front brick 13 and the adjacent first brick, which is the stretcher wall brick 16, as shown in Figure 2.

[0027] The specific vertical joints p are not continuous between adjacent rows, but are positioned at different locations. For example, as shown in Figures 1(b) and 2, the vertical joints p1 (p1') and p3 (p3') of the front bricks 13 of non-adjacent, separated rows may be positioned at the same location, or, although not shown, may be positioned at offset locations. On the other hand, the vertical joint p2 (p2') of the front brick 13 of one row is positioned at a different location from the vertical joints p1 (p1') and p3 (p3') of the front bricks 13 of the adjacent row. This is because if vertical joints are continuous across multiple rows, the brick masonry structure will be weak and prone to collapse.

[0028] When the offset between the vertical joints of the front bricks 13 in a given step and the vertical joints of the front bricks 13 in other steps is r and the step height is h, the ratio (r / h) of the offset (r) to the step height (h) is preferably 16.9% or more, more preferably 17.7% or more, and even more preferably 18.5% or more. It is also preferably 21.5% or less, more preferably 20.8% or less, and even more preferably 20.0% or less. If the ratio is greater than this range, there is a risk of vertical cracks or other fissures forming in the given step, connecting the specific vertical joints in the step above the given step with the specific vertical joints in the step below the given step. As a result, there is a high risk of the specific vertical joints in the step above the given step, the cracks in the given step, and the specific vertical joints in the step below the given step becoming connected and continuous, which makes it easier for cracks to concentrate and develop there, thereby increasing the risk of holes. On the other hand, if the thickness is less than the above range, the brick masonry structure may become weak and easily collapse.

[0029] In Figures 1(b) and 2, the positions of the vertical joints of the first and third rows of front bricks 13 are the same, so the offset width r between the vertical joints of the first row of front bricks 13 and the vertical joints of the second row of front bricks 13 is the same as the offset width r between the vertical joints of the third row of front bricks 13 and the vertical joints of the second row of front bricks 13. Incidentally, if the positions of the vertical joints of the front bricks 13 of each row are not aligned, the offset width r of the vertical joints of the front bricks 13 will differ depending on the row used. In this case, the largest offset width is used as the offset width r of the vertical joints of the front bricks 13. Although the height h of each step is the same in Figures 1(b) and 2, the height h may differ between steps. In this case, the height h of the shortest step is used. This is because cracks and chips tend to occur in a concentrated manner on the step with the largest misalignment width r or the step with the lowest height h. [Example]

[0030] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention.

[0031] (Example 1, Comparative Examples 1 and 2) The deterioration of the bricks near the vertical joint (specific vertical joint) at the boundary between the first brick (silica brick) and the second brick (high-alumina brick) in the front brick 13 of a coke oven using the brick masonry structure shown in Figures 1(a) and 1(b) was investigated. Specifically, the state of the bricks was examined for coke ovens that had been in use for more than 10 years (repeated heating and cooling of the combustion chamber (opening of the furnace lid)) and had a brick masonry structure in which the misalignment width of the specific vertical joints of the front bricks 13 was 19.2% (Example 1), 33.1% (Comparative Example 1), and 46.2% (Comparative Example 2). The state is shown in photographs (Fig. 3 (Example 1), Figs. 4(a) and (b) (Comparative Example 1), and Fig. 5 (Comparative Example 2)). The photographs for Example 1 were taken after 13.9 years, for Comparative Example 1 (a) after 11 years, for Comparative Example 1 (b) after 32 years, and for Comparative Example 2 after 16 years. Also, (a) and (b) in Figure 4 are photographs of the same coke oven battery in which no brick replacement was performed between the photographs of (a) and (b), but the photographs were taken at different positions. It should be noted that the photographs shown in FIGS. 3 to 5 were taken obliquely, and therefore the apparent deviation width differs from the actually measured deviation width.

[0032] As a result, in Example 1, even after 13 years, peeling of the brick surface of the first brick portion was observed, but no cracks or damage to the bricks were found in the specific vertical joint area (the area surrounded by the oval circle in Figure 3). On the other hand, in Comparative Example 1, after 11 years, chips (holes and dents) were observed in the specific vertical joints, as shown in Figure 4(a), particularly in the area circled. Furthermore, a through crack was observed at the location indicated by the arrow. Furthermore, after 32 years, as shown in Figure 4(b), particularly the area circled, chips were found in certain vertical joints, and cracks were also found in the bricks themselves (near the arrow). Furthermore, Comparative Example 2 was built 16 years ago, and as shown in Figure 5, particularly the area circled, the bricks in the area sandwiched between the specific vertical joints of the upper and lower rows had through cracks (arrows) that seemed to connect to the specific vertical joints of the upper and lower rows, as well as chips. [Explanation of symbols]

[0033] 11 Combustion chamber 12 Carbonization chamber 13 Front Brick 13a Second brick 13b First brick 14. Leufer Wall 15, 15a, 15b vinter wall bricks 15a' Binter wall brick edge protrusion 15c Cavity 15d burner hole 16. Reufer Wall Bricks p, p1, p1', p2, p2', p3, p3' Specific vertical joints h height of the step r Deviation width of specific vertical joint

Claims

1. A brick masonry structure of a coke oven, which is composed of stretcher wall bricks that form a stretcher wall separating the coke chamber from the combustion chamber, binder wall bricks that form a binder wall separating the combustion chamber from the other combustion chamber, and front bricks that are arranged at the kiln mouth at the end of the combustion chamber in the furnace length direction, stacked in multiple layers, The stretcher wall bricks and the binder wall bricks have a configuration consisting of first bricks, The front brick has a configuration consisting of a second brick or a configuration consisting of a first brick and a second brick, the first brick is a brick whose linear expansion coefficient changes by 0.09% or more and 0.15% or less when the temperature around the brick rises from 400°C to 600°C, whose linear expansion coefficient changes by 0.05% or more and 0.11% or less when the temperature rises by 200°C, when the temperature rises from 600°C to 800°C, and whose linear expansion coefficient changes by 0.05% or less when the temperature rises by 200°C, when the temperature rises from 800°C to 1200°C; the second brick is a brick whose change in linear expansion coefficient when the temperature around the brick rises by 200°C from 400°C to 1200°C is 0.10% or more and 0.15% or less; A brick masonry structure of a coke oven, in which the offset between the vertical joint between the second brick and the adjacent first brick in a given row and the vertical joint in another row is 16.9% or more and 21.5% or less of the height of the row.

2. 2. The brick masonry structure for a coke oven according to claim 1, wherein the first bricks are made of silica bricks, and the second bricks are made of chamotte or high-alumina bricks.

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