JP6819176B2 - How to repair the blast furnace - Google Patents

Description

The present invention relates to a method for repairing a blast furnace, which partially replaces and repairs the iron skin of the blast furnace, the stave cooler, and the refractory.

In a blast furnace of the stave cooling type, a stave cooler is installed as a furnace wall cooling device on the inner surface of the iron skin of the blast furnace. The size of one stave cooler is generally about 2 m in height, 1 m in width, and 0.3 m in thickness, and a plurality of stave coolers are provided in the height direction and the circumferential direction so as to cover the blast furnace. ..

As the wear of the blast furnace stave cooler and iron skin progresses, repair work is carried out to replace the iron skin of the repaired part including the worn part with a new iron skin. At this time, if the raw material in the furnace is charged at the height position of the worn portion, the raw material in the furnace may overflow to the outside of the furnace when the iron skin is removed. Therefore, conventionally, when repairing the iron skin of a blast furnace, the charging level of the raw material in the furnace is lowered from that of the repaired portion and the replacement work is performed. However, although it is possible to work safely, it takes a long time to shut down the blast furnace (wind break time), and it takes time to raise the raw material to the original level again after the replacement is completed, which leads to a decrease in production volume. .. Therefore, a method has been desired in which the iron skin of the repaired portion can be replaced while maintaining the level of the raw material in the furnace.

For example, in Patent Document 1, a non-aqueous hard press-fitting material is injected into the furnace through a press-fitting material injection hole drilled in the repair replacement portion of the blast furnace iron skin and the vicinity of the upper portion thereof and solidified to collapse the contents of the furnace. After blocking the above, the repair and replacement part was cut and removed, and a part of the non-aqueous hard press-fitting material alone or solidified integrally with the furnace contents was removed from the iron skin incision to form a space for the cooling device. A method for repairing a blast furnace iron skin is disclosed, in which a new iron skin having a cooling device is fitted into an incision portion of the iron skin and welded so that the cooling device fits into a space portion.

Japanese Unexamined Patent Publication No. 2005-8908

However, in Patent Document 1, a non-aqueous hard press-fitting material is press-fitted immediately inside the existing iron skin to solidify it, thereby preventing the raw material in the furnace from collapsing when the iron skin is cut and removed. And when installing a cooling device, a process of disassembling and removing the interfering part is required. In selecting the non-water-based hard press-fitting material to be press-fitted, the material is selected mainly for the purpose of solidifying the non-water-based hard press-fitting material to form a wall. Therefore, since a press-fitting material having a high fluidity for press-fitting and a high curing rate for early wall formation is selected, it is not always suitable as a press-fitting material to be used for a long period of time thereafter.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to maintain the raw material charging level in the blast furnace, and to maintain the iron skin, the stave cooler, and the refractory portion of the blast furnace. It is an object of the present invention to provide a new and improved repair method for a blast furnace, which can be replaced and repaired and whose durability after repair can be improved.

In order to solve the above problems, according to a certain viewpoint of the present invention, it is a method of repairing a blast furnace in which a part of the iron skin of the blast furnace is replaced and repaired, and a stave located between the raw material in the furnace and the iron skin. A press-fitting pipe is inserted into the disappearing part of the cooler, and the press-fitting material for the wall is press-fitted inside the furnace rather than the outside surface of the stave cooler , the adjacent stave coolers are connected, and the furnace is connected from the press-fitting material for the wall. A wall press-fitting step that solidifies the wall press-fitting material together with the furnace raw material at a position more than a predetermined distance from the iron skin in the furnace direction so that a construction space is formed on the outside, and the iron skin of the repaired part. A step of removing the iron skin that is cut and removed, and a fireproof material is installed in the construction space formed on the outside of the furnace from the press-fitting material for the wall solidified together with the raw materials in the furnace, a cooling device is installed, and a new iron skin is installed. Repair methods, including repair steps, are provided.

Insertion length of the pressed tube inserted into the furnace is preferably set below 1 50 mm or more on 5 300 mm.

As the press-fitting material for wall construction, it is preferable to use a material containing a material obtained by kneading a fire-resistant raw material having a thermosetting property and a maximum particle size of 0.5 m or less and a binder material containing a phenol resin as a main component.

Further, the press-fitting material for wall construction is preferably press-fitted into the furnace at a pressure feeding pressure of 1 MPa or more and 2 MPa or less.

The repair step consists of a refractory construction step in which a refractory is installed in the construction space formed by removing the iron skin of the repaired part, and a new iron skin is installed by installing a cooling device after the refractory is constructed. The iron skin mounting step may include a filling press-fitting material press-fitting step in which the filling press-fitting material is press-fitted between the refractory and the newly attached iron skin.

As the refractory material, a material having abrasion resistance against the raw material in the furnace is used, and as the press-fitting material for filling, a material having higher thermal conductivity than the refractory material is preferably used.

As described above, according to the present invention, it is possible to easily perform partial replacement repair of the iron skin, the stave cooler, and the refractory of the blast furnace while maintaining the raw material charging level in the blast furnace, and after the repair. Durability can also be improved.

It is a flowchart which shows the repair method of the blast furnace which concerns on one Embodiment of this invention. It is a partial explanatory view which shows one state in the press-fitting step of the press-fitting material for a wall of this embodiment, which was seen from the height direction in a plan view when the blast furnace was cut in the radial direction at the height position of the repair part. FIG. 5 is a partial explanatory view showing a state during the press-fitting step of the press-fitting material for wall construction of the present embodiment, which is viewed from the side when the blast furnace is cut in the radial direction at the repaired portion of FIG. It is a partial explanatory view which shows the state which the repair part of FIG. 3 was seen from the outside of a furnace. It is explanatory drawing which shows one state after the iron skin removal step of this embodiment which removed the iron skin of the repair part of FIG. 2 and formed the construction space. It is explanatory drawing which shows the state which attached the support member for supporting a refractory thing in a construction space. It is explanatory drawing which shows one state of this Embodiment in which the refractory construction body was formed in the construction space. It is explanatory drawing which shows one state of this Embodiment which installed the new iron skin and a cooling device. It is explanatory drawing which shows one state of this Embodiment which press-fitted the press-fitting material for filling.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, so that duplicate description will be omitted.

<1. Overview>
In the method for repairing a blast furnace according to an embodiment of the present invention, in order to replace the worn iron skin and the like while maintaining the raw material charging level in the blast furnace, the iron skin of the repaired portion is placed in the furnace before being removed. The press-fitting material for wall construction is press-fitted to form a wall so that the raw materials in the furnace do not overflow to the outside of the furnace. At this time, a press-fitting pipe is inserted into the disappearing part of the stave cooler, and the press-fitting material for wall-building is press-fitted inside the furnace rather than the outside surface of the stave cooler, and the press-fitting material for wall-building is at least a predetermined distance from the iron skin. By solidifying the raw materials in the furnace at distant positions, a construction space can be formed between the iron skin and the solidified press-fitting material for wall construction. There is a raw material in the furnace between the iron skin and the solidified press-fitting material for wall construction, but the raw material in the furnace is not solidified and can be easily removed. If there is no raw material in the furnace, the construction space is formed as it is.

The wall formed by the press-fitting material for wall construction ensures that even if the iron skin is removed, the raw materials inside the furnace do not overflow from the wall to the outside of the furnace, and a space for installing a new iron skin and cooling device is secured. it can. In addition, refractories are installed around the newly installed iron skin and cooling device to prolong their life, but it is necessary to select an appropriate material and construction method that suits the environment of the repair site. It will be possible. As a result, the durability of the iron skin and the cooling device after repair can be improved.

<2. How to repair the blast furnace>
Hereinafter, a method of repairing the blast furnace according to the present embodiment will be described with reference to FIGS. 1 to 9. Note that FIG. 1 is a flowchart showing a method of repairing the blast furnace according to the present embodiment. 2 to 9 are explanatory views showing the state of each step in the repair method of the blast furnace.

Partial replacement and repair of the iron skin, stave cooler, and refractory of the blast furnace is carried out with the blast furnace closed. This wind break is a wind break set in normal operation and does not need to be provided for this repair work. In addition, in the repair work, the raw material charging level in the blast furnace may be the same as when the wind is closed, and there is no problem even if it is higher than the repaired part.

(Press-fit pipe installation process, press-fit material press-fit process for wall construction: S100)
After the blast furnace is closed, a press-fitting pipe is inserted into the furnace and a press-fitting material for wall construction is press-fitted into the repaired portion (S100). The press-fitting material for wall-building to be press-fitted into the furnace in step S100 is press-fitted to prevent the raw materials in the furnace from overflowing when the iron skin is removed, and is separated from the iron skin in the direction of the inside of the furnace by a predetermined value or more. It is press-fitted to the position.

Here, it will be described in detail based on FIGS. 2 to 4. FIG. 2 is a partial explanatory view showing a state in which the blast furnace is viewed in a plan view from the height direction when the blast furnace is cut at the height position of the repaired portion. FIG. 3 is a partial explanatory view showing a side view of the blast furnace when the blast furnace is cut in the radial direction at the repaired portion of FIG. FIG. 4 is a partial explanatory view showing a state in which the repaired portion of FIG. 3 is viewed from the outside of the furnace.

A stave cooler 13 is arranged inside the iron skin 11 that covers the outermost part of the blast furnace 10. As shown in FIG. 4, a plurality of stave coolers 13 are arranged along the outer peripheral surface of the blast furnace. Since the stave cooler 13 comes into contact with the in-core raw material 3, it wears or reacts with the in-core raw material 3 and the in-core gas. Therefore, as shown in FIGS. 2 and 3, the stave cooler 13 wears and becomes thinner with time, and finally disappears. When the stave cooler 13 disappears, the influence on the iron skin 11 also increases, and the wear increases. In such a state, repair work such as iron skin is required. Such wear is particularly remarkable at the joint portion of the stave cooler 13.

In the present embodiment, as shown in FIGS. 2 to 4, the press-fitting pipe 33 provided in the press-fitting device 30 is inserted into the disappeared portion where the stave cooler 13 has disappeared, and the press-fitting material 5 for wall construction is press-fitted. Since the press-fitting pipe 33 is inserted into the furnace, an insertion hole is formed in the iron skin 11. The perforation position and number of the charging holes are determined by the range of the disappearing portion of the stave cooler 13. For example, as shown in FIG. 4, the six insertion holes H1 to H6 are set in the range of the disappearing portion of the stave cooler 13. , 300 mm pitch may be drilled. The pitch of the insertion holes is set to, for example, about 250 to 300 mm, and is preferably arranged in a staggered or lattice pattern.

The size of the pitch is determined based on the result of measuring the range in which the wall-building press-fitting material inserted into the raw material in the furnace extends from the tip 33a of the press-fitting pipe 33 by, for example, an offline construction test, and the disappeared portion of the stave cooler 13. The size may be determined so that it can be covered. In FIGS. 3 and 4, regions A1 to A6 indicate an expanding range of the wall-building press-fitting material 5 press-fitted from the press-fitting pipe 33 inserted through the insertion holes H1 to H6. Also in this example, the regions A1 to A6 overlap and cover the disappeared portion of the stave cooler 13. When the disappeared portion of the stave cooler 13 is large and the repair range is large, it is preferable to keep the pitch of the insertion holes constant and increase the number thereof.

The press-fitting pipe 33 inserted into the furnace through the insertion holes H1 to H6 is fixed to the iron skin 11. For example, the press-fitting pipe 33 may be fixed to the iron skin 11 by welding or the like. The inner diameter of the press-fitting pipe 33 is preferably 15 to 30 mm. If the inner diameter of the press-fitting pipe 33 is larger than 30 mm, the resistance when the press-fitting pipe 33 is inserted into the furnace becomes large, and the press-fitting pipe 33 cannot be inserted manually. On the other hand, if the inner diameter of the press-fitting pipe 33 is smaller than 15 mm, there is a concern that the wall-building press-fitting material 5 may be hardened and clogged in the pipe due to heat transfer from the inside of the furnace before being press-fitted into the furnace through the press-fitting pipe 33. is there. Therefore, the inner diameter of the press-fitting pipe 33 is preferably 15 to 30 mm. The diameter cross-sectional shape of the press-fitting pipe 33 may be circular or elliptical.

Further, the insertion length L of the press-fitting pipe 33 is also set to an appropriate length. Here, the insertion length L of the press-fitting pipe 33 refers to the length from the inner surface of the iron skin 11 to the tip 33a of the press-fitting pipe 33. In the present embodiment, the press-fitting position of the wall-building press-fitting material 5 in the radial direction of the blast furnace 10 is separated from the iron skin 11, and the disappearing portion of the adjacent stave cooler 13 is solidified together with the furnace raw material 3. The position is such that they are connected by the material 5. As a result, it is possible to easily secure a space for a cooling device and a refractory to be installed in a subsequent process on the outside of the furnace rather than the position where the wall-building press-fitting material 5 is solidified.

If the insertion length L of the press-fitting pipe 33 is too large, the wall-building press-fitting material 5 is press-fitted inside the furnace from the inside surface of the stave cooler 13, and the wall formed by the wall-building press-fitting material 5 is formed by the stave cooler 13. There is a possibility that it will fall to the lower part of the blast furnace together with the raw materials in the furnace without competing with. Therefore, the wall formed by solidifying the wall-forming press-fitting material 5 press-fitted into the furnace raw material 3 is formed at, for example, substantially the same position as the remaining furnace inner surface of the stave cooler 13. , It is preferable to determine the position of the press-fitting material 5 for wall construction. Specifically, the insertion length L of the press-fitting pipe 33 is preferably 500 mm or less. If the insertion length L of the press-fitting pipe 33 is larger than 500 mm, there is a high possibility that the wall formed by the wall-building press-fitting material 5 will not be formed.

On the other hand, the lower limit of the insertion length L is determined in consideration of the thickness of the refractory to be constructed in the subsequent process. This refractory has corrosion resistance to the in-fire material 3 and in-fire gas required for the refractory, and wear resistance to the in-fire material 3, in order to prolong the life of the equipment after restoration. Suitable materials are used. The refractory is constructed between the wall made of the press-fitting material 5 for building a wall and the newly installed iron skin. At this time, a refractory having a thickness at least necessary for protecting the iron skin is constructed. Will be done. Therefore, in order to press-fit the wall-building press-fitting material 5 so that a space equal to or larger than the thickness of the refractory to be constructed is formed between the wall formed by the wall-building press-fitting material 5 and the iron skin 11 in the radial direction, the press-fitting pipe is used. It is preferable to determine the lower limit of the insertion length L of 33.

Here, the preferred length of the insertion length L of the press-fitting pipe 33 is the radius L1 (see FIGS. 3 and 4) in which the wall-building press-fitting material 5 extends from the tip 33a of the press-fitting pipe 33 in the in-core raw material 3. It is determined based on the thickness L2 of the refractory to be constructed in the subsequent process (see FIG. 7).

First, the radius L1 at which the wall-building press-fitting material 5 spreads is determined from the range in which the wall-building press-fitting material inserted into the raw material in the furnace spreads from the tip 33a of the press-fitting pipe 33, which is measured by the above-mentioned offline construction test. Will be done. The wall-forming press-fitting material 5 press-fitted from the tip 33a of the press-fitting pipe 33 is a material having fluidity, and the gap between the raw materials 3 in the furnace is expanded substantially uniformly, but it is not always the same. .. The radius L1 in which the press-fitting material 5 for building a wall spreads is an index for determining the preferable length of the insertion length L of the press-fitting pipe 33, and therefore does not need to be strictly considered. For example, it can be obtained from an offline construction test. It may be the average value or the minimum value of the spread spread. Since the wall-building press-fitting material 5 to be press-fitted from the adjacent press-fitting pipe 33 needs to be connected after the press-fitting, the radius L1 is set to half or more of the installation interval of the press-fitting pipe 33. For example, the radius L1 is about 200 mm.

The thickness L2 of the refractory is determined from the thickness required to protect the iron skin, and is set to, for example, about 150 to 300 mm. By determining the insertion length L of the press-fitting pipe 33 in the range of 500 mm or less in consideration of these values, the preferable insertion length of the press-fitting pipe 33 can be determined.

The press-fitting device 30 installed as described above is connected to an external press-fitting material supply device (not shown) by a hose (not shown), and receives the supply of the wall-building press-fitting material 5. Then, the wall-building press-fitting material 5 passes through the press-fitting pipe 33 and is press-fitted into the furnace from the tip 33a of the press-fitting pipe 33. As shown in FIG. 2, the wall-building press-fitting material 5 extends in the direction of the arrow from the tip 33a of the press-fitting pipe 33.

As the press-fitting material 5 for wall construction, a material obtained by kneading a fire-resistant raw material having a thermosetting property and a maximum particle size of 0.5 m or less and a binder containing a phenol resin as a main component is used. For example, a resin-based mortar in which a binder containing a phenol resin as a main component is added to a fire-resistant raw material consisting of SiC: 64%, Al ₂ O ₃ : 25%, SiO ₂ : 5%, and C: 3%, and kneaded with a mixer. May be used. By using a material having a maximum particle size of 0.5 m or less, it is possible to easily enter the gap between the raw materials 3 in the furnace.

Further, as the press-fitting material 5 for wall construction, a material having thermosetting property is used because it is required to be solidified together with the raw material 3 in the furnace after press-fitting, but if it is solidified during press-fitting, it cannot be press-fitted into the furnace. Therefore, it is preferable to use a material having a property of not curing at a raw material temperature, for example, about 500 ° C. for at least 15 minutes. On the other hand, since it is not necessary to cure only the time required for the press-fitting work of the wall-building press-fitting material 5, the work of step S100 is performed by using a material having a shorter curing time after securing the time required for the press-fitting work. It is possible to shorten the time.

Further, the press-fitting material 5 for wall construction should have fluidity in order to easily enter the gap between the raw materials 3 in the furnace. For example, when expressed by the tap flow value defined by JIS R 2521, which is an index for quantitatively evaluating the flow characteristics, it is desirable that the wall-building press-fitting material 5 is a material of 300 or more.

The press-fitting material 5 for wall construction is press-fitted at a pressure feeding pressure of 1 to 2 MPa. For example, a mini cleat pump or the like is used for pumping the press-fitting material 5 for wall construction. In the present embodiment, the wall-building press-fitting material 5 does not push away the furnace raw material 3, but the wall-building press-fitting material 5 is inserted between the furnace raw materials 3 and solidified together with the furnace raw material 3. Therefore, a large pressure is not required for pressure feeding of the wall-building press-fitting material 5, and a device capable of pressure feeding with a larger pressure is also unnecessary.

Such a wall-building press-fitting material 5 is press-fitted through the insertion holes H1 to H6 at the above-mentioned pressure-feeding pressure to allow the wall-building press-fitting material 5 to flow between the raw materials in the furnace to cure the wall-building press-fitting material 5. Then, as shown in FIG. 5 described later, a wall of the wall-building press-fitting material 5 is formed so as to cover the disappeared portion of the stave cooler 13.

(Iron skin removal step: S110)
When the press-fitting material 5 for wall construction is solidified, the iron skin 11a of the repaired portion is cut and removed to form a construction space S (S110). As shown in FIG. 4, for example, the iron skin 11a of the repaired portion is determined to include a portion where the wall is formed by the wall-building press-fitting material 5. In step S110, the periphery of the iron skin 11a of the repaired portion is cut and removed by, for example, gas cutting. At this time, for safety, it may be divided into a plurality of parts (for example, divided into upper and lower parts) and cut. In this case, first, the iron skin on the upper part is removed, then the raw material in the furnace near the iron skin on which the press-fitting material 5 for wall building is not press-fitted is removed in the radial direction of the blast furnace 10, and the press-fitting material 5 for wall-building is cured. After confirming that the raw material does not collapse from the inside of the furnace, the remaining iron skin may be removed.

When the iron skin 11a of the repaired portion is removed, the raw material in the furnace in the vicinity of the iron skin on which the press-fitting material 5 for wall construction is not press-fitted is removed in the radial direction of the blast furnace 10 to form a construction space S. As a result, for example, the construction space S as shown in FIG. 5 is formed.

(Refractory construction process: S120)
Next, a refractory material is installed in the construction space (S120). When constructing a refractory, a support member 40 for supporting the refractory is attached. As shown in FIG. 6, the support member 40 is a steel frame installed inside the furnace from the outside surface of the stave cooler 13 in the construction space S. The support member 40 is composed of, for example, a support column 41 fixed to the surface side of the outside of the furnace of the stave cooler 13, and columns 43 provided on the support column 41 at predetermined intervals. The support column 43 is provided with a support metal fitting 45 that supports the refractory material. Further, a steel core 50 is attached in order to secure a space for attaching the cooling device to be installed in the subsequent process.

After that, a refractory material is installed in the construction space S. As the refractory material, a material having corrosion resistance to the furnace raw material 3 and the furnace gas and wear resistance to the furnace raw material 3 is used. By using a material having a flexural strength of 3.5 MPa or more, preferably 4.5 MPa or more after drying, which is one of the indexes of wear resistance and measured by JIS R 2553, the durability after repair is improved. be able to. For example, as the refractory, refractory components of the alumina -SiC quality or high alumina, for example, _{Al 2 O 3: 65%,} SiC: 24%, SiO 2: 5%, C: water 3 to patching material consisting of 2% .2% is added and kneaded, etc. are used. Such a refractory is driven into the construction space S where the support member 40 is constructed by using, for example, an air rammer. In this way, as shown in FIG. 7, a refractory construction body made of the refractory material 7 is formed. The outer surface of the refractory construction body may be flush with the outer surface of the stave cooler 13. The construction method of the refractory is not limited to the driving construction, and for example, a construction method such as spraying, patching, or iron coating may be selected.

Further, after the construction of the refractory construction body, the core 50 was removed to secure a space S1 for attaching the cooling device. By selecting a refractory material 7 that maintains its shape retention, the refractory material construction body does not collapse after the core 50 is removed.

(New iron skin mounting, cooling device mounting process: S130)
Next, a new iron skin (hereinafter referred to as "new iron skin") 11n that matches the shape of the iron skin 11a removed in step S110 is welded around the position where the iron skin 11 is removed. After that, the cooling device 70 was installed in the space S1 (S130). As shown in FIG. 8, the new iron skin 11n is installed so as to be substantially flush with the original iron skin 11. Further, a plurality of support hardware 60s for holding the filling press-fitting material described later are provided on the inner surface of the new iron skin 11n. The cooling device 70 is formed of, for example, copper having high heat transfer properties, is connected to an external cooling water pipe (not shown), and cools the furnace wall by circulating cooling water.

(Press-fitting material for filling, press-fitting process: S140)
After the new iron skin 11n is attached and the cooling device 70 is installed, the filling press-fitting material is press-fitted into the space S2 between the refractory construction body and the new iron skin 11n (S140). The press-fitting material for filling is press-fitted to fill the space existing inside the new iron skin 11n, and a material having higher thermal conductivity and fluidity than the refractory 7 is used. By using a material having a thermal conductivity of 3.0 W / m · K or more, preferably 3.5 W / m · K or more, as measured by JIS R 2251, the press-fitting material for filling can enjoy the cooling effect of the cooling device 70. can do. Further, if the tap flow value defined by JIS R 2521 is 200 or more, the space can be filled without gaps. For example the filling press-fitting _{material, SiC: 45%, Al 2} O 3: 38%, SiO 2: 8% to the refractory material containing, it may be used after the addition of 12% water and kneading. As shown in FIG. 9, the filling press-fitting material 9 is press-fitted into the furnace through a press-fitting hole provided in advance in the new iron skin 11n using a press-fitting device 80. As the press-fitting device 80, for example, a mini cleat pump (not shown) may be connected.

In the method of repairing the blast furnace according to the present embodiment, the refractory material 7 and the press-fitting material 9 for filling are constructed in two steps. In the refractory material 7, by using a material having corrosion resistance to the furnace raw material 3 and the furnace gas and wear resistance to the furnace raw material 3, the equipment after restoration can be used for a long time. Further, in the press-fitting material 9 for filling, by using a material having higher thermal conductivity and fluidity than the refractory material 7, it is possible to fill the gap of the construction space S and enhance the cooling effect by the cooling device 70 and the stave cooler 13. It will be possible. A large amount of water is added to the filling press-fitting material 9 in order to enhance the fluidity, and although it is inferior in corrosion resistance and wear resistance, it does not come into contact with the in-core raw material 3 and the in-core gas. In this way, by using appropriate materials, the life of the equipment after restoration can be extended.

As an example, based on the above-mentioned blast furnace repair method, the worn stave cooler was repaired as follows.

First, insertion holes for charging the press-fitting pipe of the press-fitting device into the iron skin of the blast furnace were drilled at six locations within the range where the stave cooler disappeared, in a staggered pattern at a pitch of 300 mm. Then, a press-fitting pipe having an inner diameter of 15 mm was inserted into the furnace through the insertion hole, and the wall-building press-fitting material was press-fitted at a press-fitting pressure of 1.5 MPa. At this time, the insertion length of the press-fitting pipe was set to 400 mm. The components of the press-fitting material for wall construction are as shown in Table 1 below. The amount of the wall-building press-fitting material inserted from one insertion hole was 50 to 75 kg. As a result, the press-fitting material for wall construction spreads from the tip of the press-fitting pipe (that is, at a position 400 mm from the iron skin) to a radius of about 200 mm, and a wall is formed so as to cover the disappeared portion of the stave cooler. As a result, a construction space having a radial length of about 200 mm of the blast furnace could be formed on the iron skin side of the wall. Further, since the press-fitted material for wall construction used was cured in 0.5 to 1.0 hours by the heat in the blast furnace, it was possible to immediately move to the next iron skin removing step.

About 0.5 to 1.0 hours have passed since the press-fitting material for the wall was press-fitted, and then the iron skin of the repaired portion was gas-cut and the iron skin was removed. For safety, after cutting into upper and lower parts, first remove the upper iron skin, remove the in-core raw material in the range where the iron skin press-fitting material is not press-fitted, and then remove the wall-building press-fitting material. It was confirmed that the material was hardened and the raw material did not collapse from the inside of the furnace. Then, the lower iron skin was removed. After that, the raw material in the furnace on the iron skin side of the wall formed by the press-fitting material for wall construction was removed to form a construction space.

Next, a support member for supporting the refractory was attached to the construction space. In addition, a steel core was installed to secure a space for installing the cooling device to be installed in the subsequent process. After that, a refractory material was installed in the construction space. The components of the refractory are as shown in Table 1 below, and the refractory construction body was formed by driving with an air rammer. The thickness of the refractory construction body (length in the radial direction of the blast furnace) was 170 mm, and the construction was carried out so as to be flush with the outer surface of the furnace of the surrounding sound stave cooler. Then, the core was removed to secure a space for attaching the cooling device. Since the refractory material used was selected to have shape retention, the refractory material construction body did not collapse after the core was removed.

After that, the new iron skin was welded and fixed to the existing iron skin so as to block the construction space. On the inner surface of the new iron skin, a support metal fitting for holding the press-fitting material for filling was attached to the inner side surface of the furnace in advance. After attaching the new iron skin, a copper cooling device was attached to the space formed by removing the core, and the cooling water pipe was connected. After installing the new iron skin, a press-fitting material for filling was installed in the space inside the furnace. The components of the press-fitting material for filling are as shown in Table 1 below. As the press-fitting material for filling, unlike the press-fitting material for wall construction, a water-based amorphous refractory was selected. For this reason, the press-fitting material for filling requires more time to heat-cure than the press-fitting material for wall-building, but the press-fitting material for wall-building gives priority to heat-curing in as short a time as possible in order to shorten the working time. In press-fitting for filling, priority is given to filling the space with the press-fitting material more reliably and making it in a state of high thermal conductivity, rather than shortening the time for thermosetting. Such a press-fitting material for filling was press-fitted into the furnace through a press-fitting hole previously provided in the new iron skin using a mini cleat pump.

After the above repairs were completed, the blast furnace was restarted and normal operation was resumed. The temperature of the iron skin did not rise even after one year or more after the repair, and the refractory construction body and the new iron skin are maintaining a healthy condition. In this way, by applying the blast furnace repair method according to the present embodiment, it is possible to partially replace and repair the iron skin, stave cooler, and refractory of the blast furnace while maintaining the raw material charge level in the blast furnace. Moreover, it was shown that the durability after repair can be improved.

Table 2 shows the physical characteristics of the materials used in this example. For the press-fitting material for wall construction, refractories, and press-fitting material for filling, materials having the functions required for their respective purposes were used.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person having ordinary knowledge in the field of technology to which the present invention belongs can come up with various modifications or modifications within the scope of the technical ideas described in the claims. , These are also naturally understood to belong to the technical scope of the present invention.

3 Raw material in the furnace 5 Press-fit material for wall construction 7 Refractory material 9 Press-fit material for filling 10 Blast furnace 11 Iron skin 11a Iron skin for repaired part 11n New iron skin 13 Stave cooler 30, 80 Press-fit device 33 Press-fit pipe 40 Support member 41 Support column 43 Pillars 45, 60 Support hardware 50 Core 70 Cooling device

Claims (6)

It is a method of repairing a blast furnace, in which a part of the iron skin of the blast furnace is replaced and repaired.
Insert the pressed tube loss portion of the stave cooler to be located between the furnace material and Tetsugawa, the press-fitting the Zokabe for press-fitting member to the furnace inward from the furnace outer surface of the stave cooler, adjacent the For the wall construction together with the furnace raw material at a position separated from the iron skin in the furnace interior direction by a predetermined value or more so that the stave cooler is connected and the construction space is formed on the outside of the furnace from the wall-building press-fitting material . A press-fitting step for wall-building materials that solidifies the press-fitting material, and
The iron skin removal step of cutting and removing the iron skin of the repaired part,
A repair step of the cooling device is installed, installing a new piece of the furnace shell by applying a refractory in the working space formed in Rosotogawa from the concrete wall pressed material solidified together with the furnace material,
How to repair a blast furnace, including. The insertion length of the press tube, 1 50 mm or more on 5 300 mm is set below, method of repairing a blast furnace according to claim 1 for insertion into a furnace. The press-fitting material for wall construction includes a material obtained by kneading a fire-resistant raw material having a thermosetting property and a maximum particle size of 0.5 m or less and a binder containing a phenol resin as a main component, according to claim 1 or 2. How to repair the blast furnace described in. The method for repairing a blast furnace according to any one of claims 1 to 3, wherein the press-fitting material for wall construction is press-fitted into the furnace at a pressure feeding pressure of 1 MPa or more and 2 MPa or less. The repair step
A refractory construction step of constructing the refractory in the construction space formed by removing the iron skin of the repaired portion, and
After the construction of the refractory, the cooling device is installed and the new iron skin is attached.
A filling press-fitting material press-fitting step in which a filling press-fitting material is press-fitted between the refractory material and the newly attached iron skin,
The method for repairing a blast furnace according to any one of claims 1 to 4, which comprises. The refractory material has wear resistance to the raw material in the furnace and has resistance to wear.
The method for repairing a blast furnace according to claim 5, wherein the filling press-fit material has higher thermal conductivity than the refractory material.

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