JP5251182B2 - Separation furnace bottom connection seal structure - Google Patents

Description

  The present invention relates to a seal structure of a joint portion between a separation furnace bottom provided at the bottom of a converter and a fixed furnace body in which the separation furnace bottom is fitted.

  A refractory is applied to the inner wall of the converter for decarburizing and refining the molten iron to produce the molten steel in order to hold the hot molten metal and the molten steel. This refractory is deteriorated and worn by contact with hot metal and molten steel, and repeated thermal shocks of heating and cooling. For this purpose, the refractories in the furnace are regularly replaced. In recent years, in order to increase the reaction efficiency by stirring, a tuyere is arranged at the bottom of the converter furnace, and decarburization is performed while stirring gas such as Ar gas or oxygen gas for decarburization is supplied from the tuyere into the hot metal. As a result, the furnace bottom refractory is damaged more severely than the furnace wall refractory, and the furnace wall refractory is fully usable, It has been forced to repair the furnace (refractory replacement). In order to avoid such a situation, a converter is used in which the bottom portion of the converter can be detached and the bottom portion can be replaced (see, for example, Patent Document 1). In the present invention, the removable furnace bottom portion is referred to as a separation furnace bottom, and the upper portion fitted to the separation furnace bottom is referred to as a fixed furnace body.

  Recently, for the purpose of shortening the furnace repair period of the converter, making the bottom of the converter removable is also performed (see, for example, Patent Document 2 and Patent Document 3). By applying the refractory at the bottom of the separation furnace off-line using the converter bottom as the detachable separation furnace bottom, online refractory construction at the bottom of the furnace can be omitted, and the furnace repair period is shortened accordingly. Because it is done. Recently, for the purpose of shortening the converter furnace repair period, it is becoming common to separate the converter furnace bottom.

  The separation furnace bottom maintained off-line is used by being fitted to a fixed furnace body. In recent large converters, the bottom of the separation furnace has a large diameter exceeding 4 m, and a refractory with a thickness exceeding 1.5 m is applied over the entire surface, so the mass is 50 tons. Well over. In this way, it is necessary to fit a large and heavy object to the fixed furnace body, and since the separation furnace bottom itself and the fixed furnace body itself are deformed by heat, when fitting both, the separation furnace bottom and the fixed furnace body Between the body, a gap of about 50 to 60 mm is provided on one side.

Since the hot metal and molten steel are inserted in the presence of this gap, for example, Patent Document 4 discloses a converter in which an amorphous refractory is pressed into the gap between the separation furnace bottom and the fixed furnace body. A furnace bottom structure has been proposed. However, the amorphous refractory is not dense enough to prevent the outflow of gas from the inside of the furnace. Therefore, the combustible gas in the furnace is generated from the joint of the iron shell between the separation furnace bottom and the fixed furnace body. Although there is a risk of igniting and igniting and damaging pipes and cables disposed on the furnace bottom and the furnace wall, Patent Document 4 does not describe anything in this regard, and no sealing material is disposed. In addition, Patent Documents 1 to 3 do not describe anything about the seal of the gap between the separation furnace bottom and the fixed furnace body.
JP 59-232208 A JP 11-152513 A Japanese Patent Laid-Open No. 11-61224 Japanese Utility Model Publication No. 1-58647

  The present invention has been made in view of the above circumstances, and an object of the present invention is to prevent outflow of in-furnace gas from a junction between a separation furnace bottom and a fixed furnace body in a converter having a separation furnace bottom. It is an object of the present invention to provide a connection seal structure at the bottom of a separation furnace.

  A separation furnace bottom connection portion seal structure according to a first aspect of the present invention for solving the above problems is a connection portion seal between a separation furnace bottom provided at the bottom of a converter main body and a fixed furnace body that fits the separation furnace bottom. It has a structure in which the protrusions are vertically arranged so that the protrusions do not face each other on the iron skin mating surface of the separation furnace bottom and the iron skin mating surface of the fixed furnace body facing the iron skin mating surface. A heat-resistant rope for sealing having a diameter larger than the vertical distance of the gap is arranged in the vertical gap formed by the projection on the separation furnace bottom side and the projection on the stationary furnace body side. It is what.

  According to a second aspect of the present invention, there is provided a sealing structure for a connecting portion at the bottom of the separation furnace, wherein an amorphous refractory is constructed above the heat-resistant rope for sealing.

  According to the present invention, the heat-resistant rope for sealing is arranged in a state of being sandwiched between the protrusion provided on the iron skin mating surface of the separation furnace bottom and the protrusion provided on the iron skin mating surface of the fixed furnace body. The heat-resistant rope for sealing does not deviate even when the bottom of the separation furnace is fitted to the fixed furnace body, and a stable sealing property can be ensured. Thereby, the outflow of the combustible gas from the inside of the furnace is prevented, and it becomes possible to prevent the piping and the cable from being damaged due to the combustion of the combustible gas.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic view showing a lower portion of a converter main body to which a connecting portion sealing structure according to the present invention is applied, and FIG. 2 is an enlarged view of a portion A shown in FIG.

  As shown in FIGS. 1 and 2, a converter main body 1 for containing hot metal and decarburizing and refining includes a fixed furnace body 2 fixed to a building, and a separation furnace fitted into the bottom of the fixed furnace body 2. It consists of a bottom 3. The solid furnace body 2 has a shell 6 as an outer shell, and a refractory 4 is applied to the inside of the shell 6. The refractory 4 has a two-layer structure in the order of a permanent brick layer 4b and a work brick layer (also referred to as “lined brick layer”) 4a from the iron skin 6 side. An iron skin mating surface 6 a facing the inside of the furnace is attached to the iron skin 6 at the joint with the separation furnace bottom 3, which is the lower end of the fixed furnace body 2. The height of the iron skin mating surface 6a is smaller than the thickness of the permanent brick layer 4b, and the iron skin mating surface 6a is installed on the entire circumference of the joint portion between the fixed furnace body 2 and the separation furnace bottom 3. . Furthermore, a steel flange 6b facing downward in the vertical direction is attached to the iron shell 6 at the joint between the fixed furnace body 2 and the separation furnace bottom 3. The flange 6 b is provided with a hole penetrating the bolt 12, and this flange 6 b is also installed on the entire circumference of the joint portion of the fixed furnace body 2 with the separation furnace bottom 3.

  Similarly to the fixed furnace body 2, the separation furnace bottom 3 also has an iron shell 8 as an outer shell, and a refractory 5 is applied to the inside of the iron shell 8. The refractory 5 has a two-layer structure in the order of the permanent brick layer 5b and the work brick layer 5a from the iron skin 8 side. In the periphery of the iron skin 8 of the separation furnace bottom 3, that is, at the joint portion with the fixed furnace body 2, an iron skin mating surface 8 a facing the iron skin mating surface 6 a and facing in the furnace is provided. 8 is attached. The height of the iron skin mating surface 8a is equal to the height of the iron skin mating surface 6a and is smaller than the thickness of the permanent brick layer 5b, and the iron skin mating surface 8a is the fixed furnace body 2 of the separation furnace bottom 3. It is installed all around the joint. Furthermore, a steel flange 8b facing downward in the vertical direction is attached to the iron shell 8 at the joint between the separation furnace bottom 3 and the fixed furnace body 2. This flange 8b is also installed on the entire circumference of the joint portion between the separation furnace bottom 3 and the fixed furnace body 2. The flange 8b is provided with a hole penetrating the bolt 12, and the flange 8b is configured to be connected to the flange 6b by the bolt 12 and the nut 13. That is, the separation furnace bottom 3 is configured to be fitted into a predetermined position of the fixed furnace body 2 by bringing the flange 6b and the flange 8b into contact with each other.

  A protrusion 7 is provided on the iron skin mating surface 6a, and a protrusion 9 is provided on the iron skin mating surface 8a. The projecting portion 7 and the projecting portion 9 are arranged so as to be vertically displaced so as not to oppose each other, and the projecting portion 7 and the projecting portion 9 form a vertical gap. And it is comprised so that the heat-resistant rope 10 for a seal | sticker with a larger diameter than the vertical direction distance of a gap | interval may be arrange | positioned in this clearance gap.

  In FIG. 2, the protrusion 9 provided on the separation furnace bottom 3 side is positioned vertically below the protrusion 7 provided on the fixed furnace body 2 side, and the protrusion 9 is heat resistant for sealing. It plays the role which fixes the rope 10, On the other hand, the projection part 7 bears the role which crushes the heat-resistant rope 10 for sealing. Even if the vertical positional relationship between the protrusion 7 and the protrusion 9 is opposite to that in FIG. 2, sealing is not impossible, but the separation furnace bottom 3 rises from below and fits into the fixed furnace body 2. In order to facilitate the installation of the heat-resistant rope 10 for sealing, it is preferable that the protruding portion 9 is positioned below the protruding portion 7 in the vertical direction as shown in FIG. The protrusion 7 and the protrusion 9 do not have to be disposed on the entire circumference of the iron skin mating surface 6a and the iron skin mating surface 8a. However, in order to stabilize the installation of the heat-resistant rope 10 for sealing, the iron skin mating surface 6a. And it is preferable to arrange | position to the perimeter of the iron-skin matching surface 8a. No special specification is required for the heat-resistant rope 10 for sealing, and a commercially available rope-shaped ceramic packing having a fire resistance of about 700 ° C. or more may be used. It is sufficient that the diameter of the heat-resistant rope 10 for sealing is 20 mm or more.

  An example of the furnace repair method in the converter main body 1 provided with the fixed furnace body 2 and the separation furnace bottom 3 thus configured will be described.

  When the remaining thickness of the work brick layer 4a or the work brick layer 5a is equal to or less than a predetermined value due to the decarburization refining of the hot metal, the bottom of the separation furnace is maintained in a state where the converter body 1 is maintained vertically so that the bottom portion is downward. 3 is supported by a jack (not shown) from below vertically, and the bolt 12 is opened. When all the bolts 12 are released, the jack is lowered, and the separation furnace bottom 3 is pulled away from the fixed furnace body 2 by its own weight. Then, with the separation furnace bottom 3 separated, the work brick layer 4a of the fixed furnace body 2 is removed and discharged out of the furnace. The permanent brick layer 4b of the fixed furnace body 2 does not need to be replaced, but the portion that has been damaged by long-term use is removed and discharged out of the furnace.

  After removing the work brick layer 4a and the permanent brick layer 4b at the severely damaged part, the separation furnace bottom 3 on which the work brick layer 5a and, if necessary, the permanent brick layer 5b are separately constructed, is directly below the fixed furnace body 2. Install in. Then, the heat-resistant rope 10 for sealing is placed in contact with the upper side of the protruding portion 9, and then the separation furnace bottom 3 is raised by a jack and fitted to the fixed furnace body 2. When the flange 8 b comes into contact with the flange 6 b, the jack is stopped, and the separation furnace bottom 3 is fixed to the fixed furnace body 2 by the bolt 12 and the nut 13. In this state, the heat-resistant rope for sealing 10 is fixed at the gap between the protruding portion 7 and the protruding portion 9.

  Next, in order to fix the heat-resistant rope 10 for sealing in the gap between the permanent brick layer 4b and the permanent brick layer 5b, which is formed above the heat-resistant rope 10 for sealing, and to improve the sealing performance of the joint portion, it is indefinite. The refractory 11 is constructed by an appropriate construction method such as a pouring method, a stamp method, or a press-fitting method. The construction height of the irregular refractory 11 is equal to the thickness of the permanent brick layer 4b and the thickness of the permanent brick layer 5b, and is not exposed beyond that. Thereafter, the permanent brick layer 4b of the fixed furnace body 2 is replaced as necessary, and the work brick layer 4a of the fixed furnace body 2 is sequentially applied from the peripheral side of the work brick layer 5a of the separation furnace bottom 3. In this case, it is not necessary to dispose not only the irregular refractory but also mortar between the work brick layer 5a and the work brick layer 4a, and the work brick layer 4a is applied in contact with the work brick layer 5a. Go. When the construction of the work brick layer 4a up to the upper part of the fixed furnace body 2 is completed, the furnace repair is completed, and thereafter, the process proceeds to a preparatory work such as a preheating work.

  As described above, according to the present invention, the heat-resistant rope 10 for sealing is provided with the protruding portion 9 provided on the iron skin mating surface 8 a of the separation furnace bottom 3 and the protruding portion provided on the iron skin mating surface 6 a of the fixed furnace body 2. 7, the sealing heat-resistant rope 10 is not displaced even when the separation furnace bottom 3 is fitted to the fixed furnace body 2, and the separation furnace bottom 3 and the fixed furnace body 2 are joined. A stable sealing property can be secured at the portion.

  In the above description, the work brick layer 4a of the fixed furnace body 2 is applied after the separation furnace bottom 3 is fitted to the fixed furnace body 2, but is applied before the separation furnace bottom 3 is fitted. It doesn't matter. However, in this case, since bricks are constructed separately from each other, the work brick layer 4a of the fixed furnace body 2 and the work brick layer 5a of the separation furnace bottom 3 cannot be brought into close contact with each other. Since a gap is formed between the brick layer 5a, it is necessary to construct an amorphous refractory to fill the gap. In addition, the above explanation is an example of the entire furnace repair of the converter main body 1, but only the replacement of the separation furnace bottom 3 may be used. Also in this case, since a gap is formed between the work brick layer 4a and the work brick layer 5a, it is necessary to construct an irregular refractory to fill the gap.

  Thus, in any case, by applying the present invention, it is possible to ensure a stable sealing property at the joint portion between the separation furnace bottom 3 and the fixed furnace body 2.

It is the schematic of the lower part of a converter main body to which the connection part seal structure concerning the present invention was applied. It is an enlarged view of the A section shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Converter main body 2 Fixed furnace body 3 Separation furnace bottom 4 Refractory material 5 Refractory material 6 Iron skin 6a Iron skin mating surface 6b Flange 7 Protrusion part 8 Iron skin 8a Iron skin mating surface 8b Flange 9 Protrusion part 10 Sealing heat-resistant rope 11 Indefinite refractory 12 bolt 13 nut

Claims (2)

  It is a connection seal structure between a separation furnace bottom provided at the bottom of the converter main body and a fixed furnace body for fitting the separation furnace bottom, and is opposed to the iron skin mating surface of the separation furnace bottom and the iron skin mating surface. Protrusions are arranged on the fixed surface of the fixed furnace body so that the respective protrusions do not oppose each other, and are formed by the separation furnace bottom projection and the fixed furnace body projection. A sealing structure at the bottom of a separation furnace, wherein a heat-resistant rope for sealing having a diameter larger than the vertical distance of the gap is disposed in the gap in the vertical direction.   2. The separation furnace bottom connection part sealing structure according to claim 1, wherein an amorphous refractory is applied above the sealing heat-resistant rope.

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