Repair method for deteriorated coke oven burner piping and coke oven fuel ducts

Abstract

To provide a technology that can reliably supply a fuel gas to a combustion chamber without requiring large-scale repairs, in particular, in an existing coke oven where verticality of a fuel supply duct has deteriorated due to long-term deterioration.SOLUTION: The coke oven burner piping of the present application is inserted into a combustion gas duct of an existing coke oven. Burner piping 1 comprises: insertion tubes 10, 30 divided into a plurality of parts; and joints 20, 40 provided between the insertion tubes. Play 25 is formed in a circumferential direction at a connecting part between the insertion tubes 10, 30 and the joints 20, 40.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a burner pipe used, for example, for an existing coke oven fuel duct that has deteriorated over time.

Background Art

[0002] Coke is produced by a carbonization process in which coal is baked at a high temperature (for example, 1,300 °C or higher) in a coke oven, and is mainly used in the iron-making process of steel manufacturers.

[0003] In a coke oven, a carbonization chamber and a combustion chamber are horizontally arranged alternately at the upper part. In the carbonization chamber, raw materials mainly composed of coal are carbonized to produce coke. Fuel gas and air are supplied to the combustion chamber, and combustion gas at a high temperature (for example, 1,000 °C to 1,400 °C) is generated. The carbonization chamber and the combustion chamber are separated by a wall made of refractory bricks or the like. The combustion heat is transferred to the carbonization chamber through the partition wall. Thereby, the coal in the carbonization chamber is heated.

[0004] The regenerator is provided at the lower part of the coke oven. The high-temperature exhaust gas in the combustion chamber is led to the regenerator, and a part of the retained heat is stored in the regenerator bricks. The regenerator is separated by a wall and is arranged in parallel with an air supply duct and a fuel supply duct. The heat of the regenerator is used for preheating the air introduced from the air supply duct and the fuel supply duct into the combustion chamber. The dry distillation gas (hereinafter referred to as COG) generated during coke production in the carbonization chamber is recovered, purified, and reused as new energy.

[0005] The air supply duct and the fuel supply duct communicate with the combustion chamber from below.

[0006] By the way, at the time of filing this application, the existing coke oven has passed half a century since its construction, and the deterioration over time has become prominent. In particular, due to cracks or the like in the fuel supply duct, gas leakage or the like may occur, and combustion may occur unexpectedly, and a predetermined temperature may not be obtained in the combustion chamber. The insufficient temperature causes a decrease in productivity and variations in coke quality, which are the causes of deterioration of the manufacturing function.

[0007] Even if we wanted to repair cracks in the fuel supply ducts, the existing coke ovens, built half a century ago, were not designed with repair in mind, and there is no established method for detecting where the cracks are occurring. Even if the cracks could be identified, there is not enough workspace, making repairs difficult.

[0008] Maintenance burner piping has been proposed for existing coke ovens that have deteriorated over time (for example, Patent Document 1). The maintenance burner piping is formed by connecting a ceramic pipe with a metal bellows pipe. The outer diameter of the maintenance burner piping is smaller than the inner diameter of the fuel supply duct, and the length of the maintenance burner piping is the same as the length of the fuel supply duct.

[0009] The maintenance burner piping is inserted into the existing fuel supply duct. This ensures that fuel gas is reliably supplied to the combustion chamber burner without having to repair any cracks or other damage in the fuel supply duct. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2020-158715 [Overview of the project] [Problems that the invention aims to solve]

[0011] After actually operating the maintenance burner piping described above, it became clear that the verticality of the existing fuel supply duct was worse than expected.

[0012] The maintenance burner piping also includes a section made of metal bellows. This allows it to be inserted into existing fuel supply ducts where verticality has deteriorated, by bending it as needed.

[0013] However, the main body of the above-mentioned maintenance burner piping, which is designed for high-temperature environments, is relatively long and highly rigid. This rigidity prevents the metal bellows pipe from fully exhibiting its flexibility.

[0014] Furthermore, it is difficult to identify and predict how the verticality of the existing fuel supply duct is deteriorating, and the maintenance burner piping is inserted through trial and error. As a result, it takes more time than initially anticipated. In addition, the metal bellows pipe has low rigidity, which also makes the insertion process more difficult than anticipated.

[0015] Furthermore, although the metal bellows tube has a maximum heat resistance of 1000°C and was expected to have sufficient heat resistance, it was found to deteriorate more quickly than initially anticipated.

[0016] The present invention aims to solve the above problems and to reliably supply fuel gas to the combustion chamber of an existing coke oven that has deteriorated over time, without requiring large-scale repairs.

[0017] In particular, the aim is to easily and reliably insert burner piping into fuel supply ducts where verticality has deteriorated. [Means for solving the problem]

[0018] To achieve the above objective, the present invention relates to coke oven burner piping inserted into a combustion gas duct of a coke oven. The burner piping includes multiple divided insertion pipes and joints provided between the insertion pipes, and is characterized by having circumferential play formed at the connection between the insertion pipes and the joints.

[0019] By incorporating play, an angle adjustment function is added between the insertion pipes, allowing multiple insertion pipes to be connected while accommodating the shape of fuel supply ducts with poor verticality.

[0020] More preferably, in the burner piping described above, the play is 2 to 12% of the diameter of the insertion pipe.

[0021] This allows for both angle adjustment and airtightness.

[0022] More preferably, the burner pipe includes a heat-resistant packing and a heat-resistant putty disposed between the end face of the insertion pipe and the pipe end face receiving portion of the joint.

[0023] The heat-resistant packing and the heat-resistant putty follow the movement of the end face of the insertion pipe during angle adjustment. Thereby, airtightness can be ensured.

[0024] More preferably, in the burner pipe, the insertion portion of the joint is inserted into the insertion pipe.

[0025] Thereby, it is possible to prevent the outer diameter connection portion of the burner pipe from becoming thick.

[0026] More preferably, in the burner pipe, at least the uppermost insertion pipe among the plurality of insertion pipes is made of ceramics.

[0027] Thereby, it is possible to cope with the high heat in the combustion chamber.

[0028] More preferably, in the burner pipe, the joint connected to the uppermost ceramic insertion pipe is made of ceramics.

[0029] Thereby, it is possible to cope with the high heat in the combustion chamber.

[0030] More preferably, in the burner pipe, at least the lowermost insertion pipe among the plurality of insertion pipes is made of metal.

[0031] Thereby, it is possible to cope with the self-weight of the connected insertion pipes.

[0032] More preferably, in the burner pipe, the joint connected to the lowermost metal insertion pipe is made of metal.

[0033] Thereby, it is possible to cope with the self-weight of the connected insertion pipes.

[0034] To achieve the above objective, the present invention relates to a method for installing burner piping for coke oven repair. The repair burner piping includes multiple divided insertion pipes and joints provided between the insertion pipes, and the connection between the insertion pipes and the joints has circumferential play.

[0035] The first insertion pipe is inserted into the combustion gas duct of the existing coke oven. A heat-resistant packing and uncured heat-resistant putty are placed between the end face of the insertion pipe and the pipe end face receiving portion of the joint, and the joint and the next insertion pipe are inserted. The axial angle of the insertion pipe is adjusted through the play, and the insertion of the insertion pipe and joint is repeated to connect them.

[0036] By providing play between the insertion tubes, the angle adjustment function is activated, allowing multiple insertion tubes to be connected while accommodating the shape of fuel supply ducts with poor verticality. The heat-resistant packing and heat-resistant putty follow the movement of the insertion tube end faces during angle adjustment, ensuring airtightness. Uncured heat-resistant putty will undergo plastic deformation.

[0037] More preferably, in the above method for installing the repair burner piping, the uncured heat-resistant putty hardens after the coke oven repair burner piping is installed.

[0038] This determines the shape of the burner piping for repairs. [Effects of the Invention]

[0039] According to the burner piping of the present invention, for example, in an existing coke oven that has deteriorated over time, fuel gas can be reliably supplied to the combustion chamber burner without requiring large-scale repairs.

[0040] In particular, burner piping can be easily inserted into fuel supply ducts where verticality has deteriorated. [Brief explanation of the drawing]

[0041] [Figure 1] Existing coke ovens and repair examples [Figure 2] Schematic diagram of the burner piping for repairs. [Figure 3] Detailed diagram of the burner piping for repairs. [Figure 4] Detailed diagram of the burner piping for repairs. [Figure 5] Operational diagram for repair burner piping [Figure 6] Operational diagram for repair burner piping [Figure 7] Variation [Figure 8] Variation [Figure 9] Variation [Figure 10] Variation [Modes for carrying out the invention]

[0042] ~Coke Oven~ Figure 1 shows a schematic diagram of an existing coke oven and an example of a repair. In the upper part of the coke oven, carbonization chambers and combustion chambers are arranged horizontally in alternating positions. The carbonization chambers and combustion chambers are separated by a partition wall made of heat-resistant bricks or the like. The heat of combustion generated in the combustion chamber is transferred to the carbonization chamber through the partition wall.

[0043] Air and fuel are supplied to the combustion chamber from the bottom of the coke oven via air supply ducts and fuel supply ducts. If there is deterioration such as cracks in the fuel supply duct, gas leaks will occur. The leaked gas will burn in unintended locations. As a result, the desired temperature may not be achieved in the combustion chamber.

[0044] In this invention, the repair burner piping 1 is inserted into the existing fuel supply duct. For example, the length of the existing fuel supply duct is approximately 6m, and the total length of the repair burner piping 1 is also approximately 6m. The design inner diameter of the existing fuel supply duct is 65mm, and the outer diameter of the repair burner piping 1 is 50mm. Note that these values ​​are examples to aid in understanding the invention and are not limiting. In other words, it is sufficient that the repair burner piping 1 can be inserted into the existing fuel supply duct. The same applies to the other values.

[0045] This allows for the reliable supply of fuel gas to the combustion chamber of existing coke ovens that have deteriorated over time, without requiring large-scale repairs.

[0046] ~Overview of burner piping for repairs~ Figure 2 shows a schematic example of the repair burner piping configuration. Assuming the total length of the repair burner piping 1 is approximately 6m, twelve insertion pipes of approximately 500mm in length are connected.

[0047] In the illustrated example, the structure consists of 10 ceramic tubes 10 and 2 metal tubes 30. Joints are provided between the insertion tubes. The joints can be made of ceramic 20 or metal 40. In the illustrated example, ceramic joints 20 are placed between the ceramic tubes 10, 10, metal joints 40 are placed between the ceramic tubes 10 and the metal tubes 30, and metal joints 40 are placed between the metal tubes 30, 30.

[0048] At the very least, the uppermost insertion tube connected to the combustion chamber is preferably made of ceramics. Although the combustion chamber reaches high temperatures (e.g., 1000-1400°C), even ceramics can achieve heat resistance of 1500°C or higher.

[0049] However, ceramic tubes 10 are more expensive than metal tubes and have inferior load-bearing capacity. When the insertion tubes are connected vertically, the weight of the tube itself cannot be ignored at the bottom. Also, in areas where the assumed temperature does not exceed 1000°C (for example, assumed temperature of 800°C or less), ceramic tubes are not necessary. For these reasons, it is preferable that at least the lowest insertion tube be made of metal. Metal tubes 30 can reduce costs and withstand the weight of the connected insertion tubes.

[0050] The materials for the insertion tube and joint described above are examples only and should be appropriately selected within the scope of the technical concept of the invention (see the modified examples below).

[0051] ~Detailed configuration of connected structure~ Figures 3 and 4 are detailed diagrams of the connection structure of the repair burner piping. Figure 3 is a schematic perspective view, and Figure 4 is a schematic plan view.

[0052] The joint 20 consists of upper and lower insertion portions 21, 21 and a pipe end face receiving portion 22 provided between the insertion portions 21, 21. The insertion portions 21 are inserted into the ceramic pipe 10. The end face of the ceramic pipe 10 is in contact with the pipe end face receiving portion 22 via a heat-resistant packing 28 and a heat-resistant putty 29.

[0053] While the joint 20 may externally insert the ceramic pipe 10, if the external insertion structure becomes too thick compared to the pipe diameter, it may become difficult to insert into the existing fuel supply duct. An internal insertion structure in which the insertion part 21 is internally inserted into the ceramic pipe 10 is preferable as it facilitates the insertion of the repair burner piping 1 into the existing fuel supply duct.

[0054] In the internal structure of the ceramic tube 10 and the joint insertion portion 21, it is preferable to have an appropriate amount of play 25. The play 25 is formed along the circumferential direction between the inner circumference of the ceramic tube 10 and the outer circumference of the insertion portion 21.

[0055] In the illustrated example, when the inner diameter of the ceramic tube 10 is 42 mm, the outer diameter of the insertion portion 21 is 40 mm, and a clearance of 1 mm (2 mm total) of play 25 is provided at both ends. The clearance ratio is approximately 2 / 42 = 5%. A clearance ratio of 2 to 12% is preferable. A clearance ratio of 4 to 8% is even more preferable. If the clearance ratio is too small, the angle adjustment function (details described later, see Figures 5 and 6) will be insufficient. If the clearance ratio is too large, the connection will be insufficient, and there will be a risk of gas leakage.

[0056] In the prototype example, the risk of gas leakage became significant when the play ratio exceeded approximately 5 / 42 = 12%.

[0057] The insertion length of joint 20 should preferably be around 10-20 mm. If the insertion length is too short, the connection will be insufficient and there will be a risk of gas leakage. If the insertion length is too long, the angle adjustment function (details below, see Figures 5 and 6) will be insufficient.

[0058] The insertion tubes 10 and 30 of this invention are highly rigid and inflexible, but the play 25 compensates for this lack of flexibility.

[0059] However, intentionally creating a gap 25 reduces airtightness. Therefore, a heat-resistant packing 28 and heat-resistant putty 29 are provided between the end face of the ceramic pipe 10 and the pipe end face receiving portion 22.

[0060] The heat-resistant packing 28 is mainly composed of alumina fibers or glass fibers, and can be expected to withstand temperatures of around 1400°C. The heat-resistant packing 28 maintains airtightness while following the movement of the end face of the ceramic tube 10.

[0061] The heat-resistant putty 29, for example, has aluminum hydroxide as its main component and can be expected to withstand temperatures of around 1200°C. The uncured putty is plastic and deforms to follow the movement of the end face of the ceramic tube 10 while maintaining airtightness. It hardens in that shape upon heating. For example, putty with aluminum hydroxide as its main component dehydrates upon heating and becomes ceramic-like aluminum oxide.

[0062] Therefore, the heat-resistant packing 28 and heat-resistant putty 29 compensate for the reduced airtightness due to the play 25.

[0063] ~Operation~ Figure 5 is a detailed diagram of the connection structure for the repair burner piping. For example, if a ceramic pipe 10 with an inner diameter of 42 mm is given a 1 mm gap 25 at both ends and the joint 20 is inserted to a length of approximately 10-20 mm, an angle adjustment of approximately 3-5 degrees (on one side) is possible. An angle adjustment of up to approximately 10 degrees is possible using the joint 20 vertically. Furthermore, if a ceramic pipe 10 with an inner diameter of 42 mm is given a 2 mm gap 25 at both ends and the joint 20 is inserted to a length of approximately 10-20 mm, an angle adjustment of approximately 5-10 degrees (on one side) is possible. An angle adjustment of up to approximately 20 degrees is possible using the joint 20 vertically.

[0064] First, the uppermost ceramic pipe 10 is inserted into the existing fuel supply duct. Next, the ceramic joint 20 is placed together with the heat-resistant packing 28 and heat-resistant putty 29, and the next ceramic pipe 10 is inserted into the existing fuel supply duct. As a result, the preceding ceramic pipe 10 is pushed upward.

[0065] If the verticality of the existing fuel supply duct deteriorates, the angle adjustment function of the play 25 will activate, and the preceding ceramic pipe 10 will conform to the inclination of the existing fuel supply duct. Furthermore, the heat-resistant packing 28 and heat-resistant putty 29 will follow the movement of the lower end face of the preceding ceramic pipe 10.

[0066] The ceramic pipe 10 and ceramic joint 20 are repeatedly inserted, and metal pipe 30 and metal joint 40 are inserted as needed to connect each pipe and form the repair burner piping 1. At this time, the angle adjustment function of the play 25 is activated each time there is a bend in the existing fuel supply duct.

[0067] When the repair burner piping 1 is in place, the heat-resistant putty 29 is uncured and undergoes plastic deformation. However, after installation, it hardens upon heating while maintaining its shape, ensuring airtightness. This finalizes the shape of the repair burner piping 1.

[0068] Figure 6 is a diagram illustrating the further operation of the angle adjustment function of the play 25. Figure 5 explained the angle adjustment function of one play 25. By linking multiple angle adjustment functions of play 25, it is possible to accommodate complex degraded fuel supply duct shapes.

[0069] Figure 6A shows the case where the structure tilts significantly in one direction. The angle adjustment functions of the two "play" sections 25 operate in the same direction, allowing for adaptation to large tilts. By combining multiple "play" sections 25, even larger tilts can be accommodated.

[0070] Figure 6B shows the case where the tilt is in a fine S-shape. The angle adjustment functions of the two play 25s operate in opposite directions, allowing it to accommodate even fine S-shaped tilts. By combining multiple play 25s, it can accommodate more complex tilts.

[0071] ~Effects~ Although it is difficult to identify and predict how the verticality of the existing fuel supply duct has deteriorated, the repair burner piping 1 is inserted while deforming to correspond to the shape of the deteriorated fuel supply duct. At this time, the deteriorated fuel supply duct does not require major repairs. As a result, fuel gas can be reliably supplied to the combustion chamber of an existing coke oven that has deteriorated over time without requiring major repairs.

[0072] The ceramic tube 10 and the metal tube 30 are highly rigid, making insertion easy.

[0073] Furthermore, the ceramic tube 10 and ceramic joint 20 can be placed in the high-temperature region, suppressing the effects of high heat in the combustion chamber and enabling relatively long-term operation.

[0074] ~Variations~ The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the technical concept of the present invention.

[0075] In the modified example shown in Figure 7, the repair burner piping 1 is entirely made of ceramic pipes 10 and ceramic joints 20. This modified example can be used when the temperature is relatively high throughout the entire area, the total length is short, and the effect of self-weight is minimal.

[0076] In the modified example shown in Figure 8, the repair burner piping 1 is formed entirely from metal pipes 30 and metal joints 40. As shown in Figure 9B (described later), if it is not necessary to extend the repair burner piping 1 to the combustion chamber, it is not necessary to place an insertion pipe in the high-temperature region. In such cases, as in this modified example, it is possible to use only metal pipes 30 and metal joints 40.

[0077] In the modified example shown in Figure 7, all materials are made of ceramics, and in the modified example shown in Figure 8, all materials are made of metal. However, ceramics and metal can be used as appropriate.

[0078] In the modified example shown in Figure 9A, the bellows tube 50 used in the conventional example may also be used as appropriate. In the present invention, many heat-resistant ceramic tubes can be used. As a result, the bellows tube 50 can be used while avoiding the high-temperature region. The bellows tube 50 is inserted in places where the angle adjustment function of the play 25 cannot be used. The bellows tube 50 can be made relatively short and easy to handle even with low rigidity.

[0079] In the modified example shown in Figure 9B, the repair burner piping 1 does not reach the combustion chamber. The existing fuel supply duct immediately adjacent to the combustion chamber is visible, and its deterioration can be determined. Even if there is deterioration, it can be easily repaired. If it can be confirmed that there is no deterioration at the top of the existing fuel supply duct, it is not necessary to extend the repair burner piping 1 to the combustion chamber. For example, it can also be done as shown in the modified example in Figure 8.

[0080] The modified example shown in Figure 10 is an external joint. In the above embodiment, for example, it is assumed that an insertion pipe with an outer diameter of 50 mm is inserted into an existing fuel supply duct with an inner diameter of 65 mm, and an internal structure is assumed from the viewpoint of ease of insertion work (see Figure 3). However, if there is sufficient slack in the dimensions of the existing fuel supply duct, an external structure as shown in the modified example may be used.

[0081] In the extrapolated structure, play is formed along the circumferential direction between the inner circumference of the joint and the outer circumference of the ceramic tube.

[0082] In the above embodiment, the repair of an existing coke oven fuel duct that has deteriorated over time is assumed, but for example, the burner piping 1 may be pre-inserted into a newly installed coke oven fuel duct. When deterioration occurs over time after the start of use, it can be replaced with new burner piping as appropriate. [Explanation of Symbols]

[0083] 1. Repair burner piping 10 ceramic tubes 20 Ceramic joints 21 Joint insertion part 22 Pipe end receiving part 25 Play 28 Heat-resistant gasket 29 Heat-resistant putty 30 metal tube 40 Metal joints 50 bellows tube

Claims

1. Coke oven burner piping inserted into the combustion gas duct of a coke oven, The insertion tube is divided into multiple sections, A joint provided between the aforementioned insertion tubes, Includes, The connection between the insertion tube and the joint has play formed in the circumferential direction. Coke oven burner piping characterized by the following features.

2. The aforementioned play is 2-12% of the insertion tube diameter. The coke oven burner piping according to claim 1.

3. Includes a heat-resistant packing and heat-resistant putty placed between the end face of the insertion tube and the end face receiving portion of the joint. The coke oven burner piping according to claim 1.

4. The insertion portion of the joint is inserted into the insertion tube. The coke oven burner piping according to claim 1.

5. Of the multiple insertion tubes, at least the uppermost one is made of ceramic. The coke oven burner piping according to claim 1.

6. The joint connected to the uppermost ceramic insertion tube is made of ceramic. The coke oven burner piping according to claim 5, characterized in that it is a coke oven burner piping.

7. Of the multiple insertion tubes, at least the lowest one is made of metal. The coke oven burner piping according to claim 1.

8. The joint connected to the lowermost metal insertion tube is made of metal. The coke oven burner piping according to feature 7.

9. A method for installing coke oven burner piping, comprising multiple divided insertion pipes and joints provided between the insertion pipes, wherein there is circumferential play formed at the connection between the insertion pipes and the joints, The first insertion pipe is inserted into the combustion gas duct of the existing coke oven. Insert the joint and the next insertion pipe while placing a heat-resistant packing and uncured heat-resistant putty between the end face of the insertion pipe and the pipe end face receiving portion of the joint. The axial angle of the insertion tube is adjusted through the aforementioned play. The insertion tube and joint are repeatedly inserted and connected. A method for installing coke oven burner piping, characterized by the following features.

10. The aforementioned uncured heat-resistant putty hardens after the coke oven burner piping is installed. The method for installing coke oven burner piping according to claim 9.

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