JP5347873B2 - Hot air branch structure of a hot blast furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for constructing a hot-blast divided tube in a hot-stove for blast furnace, wherein various problems related to an elastic coupling can be avoided by dispensing with the elastic coupling. <P>SOLUTION: The lengths of the vertical part 6 and the horizontal parts 5, 7 of the hot-blast divided tube 4, are respectively made to be three or more times the tube diameter, thereby, even when the difference of the heat-displacement or the heat-displacement itself is caused, the heat-displacement can be absorbed with the elastic deformation of the tube itself. As a result, an elastic coupling is not needed to use and the various problems related to the elastic coupling can be avoided. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a hot air branch pipe structure in a hot blast furnace of a blast furnace, and is particularly suitable for a hot air branch pipe portion connecting a hot blast furnace main body and a hot air main pipe connected to an annular pipe of the blast furnace.

  A hot blast furnace, which is an auxiliary facility of a blast furnace, is for heating and raising the air blown from the tuyere, and is roughly classified into a small internal combustion type hot blast furnace and a large external combustion type hot blast furnace. In the external combustion type hot stove, the heat storage chamber and the combustion chamber are separated, and the upper dome is connected to each other. Conventionally, this connection structure is provided with an expansion joint having a bellows structure called a bellows so as to absorb the difference in thermal displacement generated in the heat storage chamber and the combustion chamber or the thermal displacement itself generated in the connection structure itself. In addition, a tension beam for taking a so-called reaction force is generally used for the use part of the expansion joint. Moreover, in order to protect the iron skin which comprises the outer shell of a hot-blast furnace from the high temperature of a hot air, it is necessary to pile a brick inside an iron skin. It is necessary to pile up this brickwork not only in the hot air furnace but also in all parts through which the hot air passes.

  However, with an expansion joint having a bellows structure, brickwork is very complicated and difficult. In addition, at locations where expansion and contraction occurs, it is necessary to stack with a gap between the bricks so as to absorb the expansion and contraction, and at expansion joints that repeatedly expand and contract over many years, the bricks wear and fall off, and the iron skin becomes red hot The problem arises. There is also a problem that the bellows portion of the expansion joint itself is damaged by stress corrosion cracking.

  Therefore, the present applicant has previously proposed a connection structure of an external combustion type hot stove capable of connecting a heat storage chamber and a combustion chamber without using an expansion joint, as described in Patent Document 1 below. In this connection structure, when the dome of the heat storage chamber and the dome of the combustion chamber are connected by a connecting pipe, the ratio RD / TD between the pipe diameter RD of the connecting pipe and the dome diameter TD of the heat storage chamber is 0.24 or more and 0.60 or less. By making the ratio RD / TD of the pipe diameter RD of the connecting pipe and the dome diameter ND of the combustion chamber to be 0.44 or more and 0.60 or less, the drift of the gas in the furnace is prevented and the local knuckle portion of the connecting pipe is locally Therefore, it was possible to connect the heat storage chamber and the combustion chamber without expansion joints.

JP 7-11316 A

However, in a hot air furnace, there is also a connecting portion between a combustion chamber (including a heat storage chamber integrated) and a hot air main pipe, a so-called hot air branch pipe, and this hot air branch pipe also absorbs the difference in thermal displacement and the thermal displacement itself. Since the expansion joint is used and the tension beam used to take the so-called reaction force is used at the location where the expansion joint is used, the structure becomes complicated, the iron skin becomes red hot, There is a problem that the expansion joint itself is damaged.
The present invention has been made paying attention to the above-described problems, and provides a hot air branch pipe structure for a hot blast furnace of a blast furnace that can eliminate the need for an expansion joint and avoid various problems related to the expansion joint. It is for the purpose.

In order to solve the above problems, the hot air branch structure of the hot blast furnace of the blast furnace of the present invention is a hot air branch pipe interposed between the hot blast furnace body and the hot air main pipe connected to the annular pipe of the blast furnace, The length of the vertical part and the horizontal part of the hot air branch pipe is set to be three times or more of the respective pipe diameters.
In addition, the length of a vertical part and a horizontal part is the length between centerlines of each pipe | tube.

  Thus, according to the hot air branch pipe structure of the blast furnace of the present invention, the length of the vertical part and the horizontal part of the hot air branch pipe is set to be three times or more of the respective pipe diameters, Even if thermal displacement itself occurs, it can be absorbed by elastic deformation of the tube itself. As a result, it is not necessary to use an expansion joint, and various problems associated with the expansion joint can be avoided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a general view which shows one Embodiment of the hot-air branch pipe structure of the hot-blast furnace of the blast furnace of this invention. It is a general view which shows various embodiment of the hot air branch pipe structure of the hot blast furnace of the blast furnace of this invention. It is a general view which shows an example of the hot air branch pipe structure of the hot blast furnace of the conventional blast furnace.

Next, an embodiment of the hot air branch pipe structure of the blast furnace of the present invention will be described with reference to the drawings.
FIG. 1 is an overall view of a hot air branch pipe structure of a hot stove according to the present embodiment. Reference numeral 1 in the figure denotes a heat storage chamber, and reference numeral 2 denotes a combustion chamber. Moreover, the code | symbol 8 in a figure is a hot-air main pipe connected to the annular pipe of a blast furnace. The hot air branch pipe 4 refers to a connecting pipe structure from the combustion chamber 2 to the hot air main pipe 8. In the hot stove of this embodiment, an expansion joint is not used at the connecting portion between the heat storage chamber 1 and the combustion chamber 2. Moreover, although the outer shell of all of the heat storage chamber 1, the combustion chamber 2, the hot air branch pipe 4, and the hot air main pipe 8 is covered with a so-called iron skin, bricks for protecting the iron skin are stacked therein. Brick is specially stacked to absorb thermal expansion and contraction.

  The hot air branch pipe 4 of this embodiment includes a hot air branch first horizontal part 5 connected to the combustion chamber 2, a hot air branch vertical part 6 connected to the hot air branch first horizontal part 5, a hot air branch vertical part 6 and a hot air main pipe. And a hot-air branch pipe second horizontal portion 7 that connects the two. Each part of the hot air branch pipe 4 is heated only from the normal temperature at the beginning of construction to about 100 ° C. at the time of operation due to bricks stacked inside, but a difference in thermal displacement due to thermal deformation or the thermal variation itself occurs. . Therefore, conventionally, as shown in FIG. 3, the expansion joint A is used for the hot air branch first horizontal part 5 and the hot air branch second horizontal part 7 to absorb them. In addition, a tension beam 3 for taking the reaction force is also provided at the site where the expansion joint A is used.

  As described above, the expansion joint A has various problems due to its use. Therefore, in the present embodiment, as shown in FIG. 1, the length of the hot air branch first horizontal portion 5 is set to be not less than three times the diameter of the hot air branch first horizontal portion 5 and the length of the hot air branch vertical 6 is longer. Is set to at least three times the tube diameter of the hot air branch pipe vertical portion 6 and the length of the hot air branch pipe second horizontal portion 7 is set to be at least three times the tube diameter of the hot air branch second horizontal portion 7. The structure was not used. Each tube diameter indicates the outer diameter of the tube portion. Moreover, each length shows the distance between the intersections of the centerline in the connection location with the pipe part to connect.

By satisfying such a diameter and length of the tube diameter, for example, the difference between the heat displacement of the hot air branch first horizontal portion 5 and the heat displacement of the hot air branch second horizontal portion 7 or the hot air branch vertical portion 6 itself. The thermal displacement itself can be absorbed by the elastic deformation of the hot air branch pipe vertical portion 6, and as a result, the expansion joint is not necessary. For example, it is an analysis result by the finite element method when internal pressure and thermal expansion are applied in a hot blast furnace of a 5,000 m ³ blast furnace. Although it was found that this occurred, the magnitude was 210 N / mm ² , which was within the tolerance of fatigue endurance stress.

  FIG. 1 shows a so-called best mode in which the expansion joint is not used in the connecting portion between the heat storage chamber 1 and the combustion chamber 2 using the technique described in Patent Document 1, but the blast furnace hot stove of the present invention In the hot air branch pipe structure, it is not necessarily assumed that the expansion joint is not used. In FIG. 2 a, the expansion joint A and the tension beam 3 are used for the hot air branch second horizontal portion 7. In FIG. 2 b, the expansion joint A and the tension beam 3 are used for the hot air branch first horizontal portion 5. Further, FIG. 2 c uses the expansion joint A and the tension beam 3 at the connecting portion between the heat storage chamber 1 and the combustion chamber 2. Further, in FIG. 2 d, the expansion joint A and the tension beam 3 are used for the connecting portion of the heat storage chamber 1 and the combustion chamber 2 and the hot air branch first horizontal portion 5. In FIG. 2 e, the expansion joint A and the tension beam 3 are used for the connecting portion of the heat storage chamber 1 and the combustion chamber 2 and the hot air branch second horizontal portion 7.

However, in any of the embodiments, the length of the hot air branch first horizontal portion 5 is three times or more the diameter of the hot air branch first horizontal portion 5 and the length of the hot air branch vertical 6 is the hot air branch vertical portion. 6 and the length of the hot air branch second horizontal portion 7 is three times or more the tube diameter of the hot air branch second horizontal portion 7. Therefore, in each pipe part constituting the hot air branch pipe 4, since the difference in thermal displacement and the thermal displacement itself can be absorbed by its own elastic deformation, even if an expansion joint is used, the load on the expansion joint is small. Further, since deformation (displacement) is small, it does not become a big problem as in the conventional case.
Thus, in the hot air branch structure of the hot blast furnace of the blast furnace of the present embodiment, the length of the vertical portion 6 and the horizontal portions 5 and 7 of the hot air branch tube 4 is set to be three times or more of the respective tube diameters. Even if a difference in displacement or a thermal displacement itself occurs, it can be absorbed by elastic deformation of the tube itself. As a result, it is not necessary to use an expansion joint, and various problems related to the expansion joint can be avoided.

  1 is a heat storage chamber, 2 is a combustion chamber, 3 is a tension beam, 4 is a hot air branch pipe, 5 is a hot air branch first horizontal part, 6 is a hot air branch pipe vertical part, 7 is a hot air branch second horizontal part, and 8 is a hot air main pipe , A is an expansion joint

Claims (1)

  In the hot air branch pipe interposed between the hot air furnace main body and the hot air main pipe connected to the annular pipe of the blast furnace, the length of the vertical portion and the horizontal portion of the hot air branch tube is set to three times or more of the respective diameters. A hot air branch structure of a hot blast furnace of the blast furnace characterized by that.

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