JP2010100901A - Method for operating heating furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for operating a heating furnace, in which the material to be heated is uniformly heated while preventing heat-deviation from being caused on the lower surface of a material to be heated, by a conveying device. <P>SOLUTION: There is disclosed the method for operating the heating furnace, in which the conveying device for conveying the material 2 to be heated in the furnace length direction, is arranged at the lower part of the heating furnace 1 and also, two sets of burners 5 faced in the furnace width direction, are arranged at the sidewall 4 of the lower part of the heating furnace, in parallel to the furnace length direction in order to heat the lower surface of the material to be heated, wherein these two sets of burners are simultaneously burnt with one pair of burners adjoined in the sidewall, are alternately burnt and this burner is the heat-storing alternative-combustion type burner. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method of operating a heating furnace in which a conveying device that conveys a material to be heated in the furnace length direction is disposed in a lower part of the heating furnace.

  As a heating furnace in which a conveying device for conveying a material to be heated in the furnace length direction is provided at the lower part of the heating furnace, a walking beam furnace, a pusher furnace, and the like are mainly known. A walking beam type furnace is generally driven by a walking beam method, and is composed of a fixed skid beam fixed in the furnace and a movable skid beam movable in the transfer direction (walking beam and skid beam). Called). Specifically, as disclosed in Patent Document 1, the walking beam furnace is a heating furnace in which steel slabs are sequentially moved by a transfer device while being heated from a carry-in port toward a carry-out port. A heat storage burner is a structure provided above and below the billet.

  Further, as disclosed in Patent Document 2, a heating furnace that supports a material to be heated by a conveying device and heats the material to be heated while being conveyed from the charging side to the extraction side, the conveying device on the extraction side Is shifted in the furnace width direction, and combustion and non-combustion are periodically repeated on the heating furnace side wall parallel to the transfer device in the lower combustion zone of the zone in which the position of the transfer device is shifted in the furnace width direction. Some walking beam furnaces have a structure in which a plurality of alternating combustion burners are provided.

On the other hand, the pusher type furnace is fixedly arranged in the furnace, for example, as disclosed in Patent Document 3, and has a fixed skid beam composed of a skid pipe and a skid rail, and can slide on the skid rail and keep the rolling material constant. It has a transport device that consists of a pusher that pushes it into the furnace for each stroke.
Japanese Patent No. 2796027 JP 10-317053 A JP-A-7-252520

  By the way, in the above-mentioned conventional heating furnace represented by a walking beam type furnace and a pusher type furnace, uniform heating of the material to be heated is an important factor affecting the quality of the product. For this reason, in such a heating furnace, with respect to the burners provided at the upper and lower portions of the side wall, a pair of two burners facing in the furnace width direction are paired, and these materials are alternately burned to obtain a material to be heated. The method of heating uniformly was taken. This is intended to heat the material to be heated uniformly by the radiation of the flame by jetting the flame from one burner in the furnace width direction substantially parallel to the upper and lower surfaces of the material to be heated. It is. Thereby, uniform heating was possible on the upper surface of the material to be heated. However, on the lower surface of the material to be heated, there is a problem that a low temperature portion is generated by blocking the flame radiation as a shadow of the conveying device. In particular, the fixed skid beam and the movable skid beam are arranged facing each other at a predetermined interval in the furnace width direction, and in the area between them, the shadowed parts are aggregated, There was a problem that the material to be heated was biased by the low temperature part that was blocked by the flame radiation.

  The present invention has been devised in view of the above-described conventional problems, and is a heating furnace capable of uniformly heating a heated material by preventing the occurrence of uneven heat on the lower surface of the heated material by a conveying device. The purpose is to provide a method of operation.

  The operating method of the heating furnace according to the present invention is provided with a conveying device for conveying the material to be heated in the furnace length direction at the lower part of the heating furnace, and the lower surface of the material to be heated is disposed on the side wall of the lower part of the heating furnace. A heating furnace operating method in which two burners facing each other in the furnace width direction for heating are arranged in the furnace length direction, and the two burners are burned simultaneously.

  The burner is characterized in that a pair adjacent to the side wall is alternately burned.

  The burner is a heat storage alternating combustion burner.

  The transport device is a skid beam disposed near a center in the furnace width direction and spaced apart from each other by a predetermined distance.

  The predetermined interval is set to ½ or less of the furnace width.

  In the operation method of the heating furnace according to the present invention, it is possible to uniformly heat the heated material by preventing the occurrence of uneven heat on the lower surface of the heated material by the conveying device.

  Hereinafter, a preferred embodiment of a method for operating a heating furnace according to the present invention will be described in detail with reference to the accompanying drawings. In the operation method of the heating furnace 1 according to the present embodiment, a conveying device that conveys the material to be heated 2 from the carry-in port to the carry-out port in the furnace length direction is disposed at a lower portion thereof, and A heating furnace 1 is used in which a plurality of burners 5 for heating the lower surface are arranged in parallel in the furnace length direction at the upper and lower portions of the side wall 4. Fig.1 (a) is a sectional side view which shows the outline | summary of the heating furnace 1 concerning this invention, FIG.1 (b) is a plane sectional view which shows the outline | summary of the heating furnace 1 of Fig.1 (a). The illustrated heating furnace 1 heats a metal material such as a steel piece as a material to be heated 2 by using a skid beam 3 which is disposed near a center in the furnace width direction and spaced apart from the center of the conveying apparatus. It is a walking beam type heating furnace. As shown in FIG. 1B, the material to be heated 2 is continuously conveyed in various widths in the furnace width direction.

  The skid beam 3 is disposed on the furnace bottom and includes a fixed skid beam 3a and a movable skid beam 3b. In the illustrated example, the skid beam 3 composed of a fixed skid beam 3a and a movable skid beam 3b adjacent to each other is disposed at a predetermined interval in the furnace width direction. These skid beams 3 are provided close to the heated material 2 having the minimum width w1, which will be described later, at the center in the furnace width direction with an interval at which the material can be placed. The heated material 2 placed on the fixed skid beam 3a moves to the carry-out port 10 side while being supported by the movable skid beam 3b as the movable skid beam 3b rises and moves to the carry-out port 10 side. . In this state, the movable skid beam 3b descends and returns to the original position. By repeating this, the skid beam 3 conveys the heated material 2 from the carry-in port to the carry-out port 10.

  Burners 5 are disposed on the left and right side walls 4 of the heating furnace 1 on the upper and lower sides of the material to be heated 2. A plurality of burners 5 on the left and right side walls 4 are arranged side by side at appropriate intervals in the furnace length direction. Also, the burners 5 on the left and right side walls 4 are arranged at positions facing each other. An upper heating zone 6 is formed as a combustion region of the burner 5 provided side by side on the upper side of the side wall 4. Further, a lower heating zone 7 is formed as a combustion region of the burner 5 provided in parallel with the lower portion of the side wall 4.

  In the present embodiment, the burner 5 is a regenerative alternating combustion burner. As shown in FIGS. 2 and 3, the heat storage alternating combustion burner is composed of a pair of two units. As shown in FIGS. 2 and 3, an air supply blower 9a for supplying combustion air to the burner on the combustion side, and an exhaust blower 9b for sending exhaust gas to the outside of the furnace. Are switched by the switching valve 8 and alternately burned. The heat storage alternating combustion burner is provided with a heat storage body at the back of the burner opening, and the heat storage body warmed by the exhaust gas during non-combustion heats the combustion air during combustion, thereby efficiently heating the interior of the furnace.

  In the present embodiment, the following operating method is used in the heating furnace 1 having the above configuration. FIG. 2 is a state diagram showing the combustion state of the burner 5 in the upper heating zone 6. FIG. 3 shows a state diagram representing the combustion state of the burner 5 in the lower heating zone 7. FIG. 4 is a front sectional view showing a combustion state of the burner 5 in the heating furnace 1.

  In the upper heating zone 6, as usual, two burners 5 facing in the furnace width direction are paired and burned alternately. From one of these facing burners 5, a flame is ejected in the furnace width direction, and this flame is ejected substantially parallel to the upper surface of the heated material 2 over almost the entire length of the heated material 2. The temperature distribution in the furnace width direction becomes uniform, and the upper surface of the material to be heated 2 is heated uniformly. In the upper heating zone 6, flames are ejected in a staggered manner as shown in FIG. 2 by alternating the combustion timings of the two pairs of burners 5 adjacent to the side walls 4.

  On the other hand, in the lower heating zone 7, if the two burners 5 facing in the furnace width direction are alternately burned as in the prior art, the skid beam 3 becomes an obstacle. For this reason, in the region S1 between the pair of skid beams 3, a low temperature portion that blocks the flame radiation is generated as compared with the region S2 between the skid beam 3 and the burner 5 facing the skid beam 3. However, in this embodiment, in the lower heating zone 7, the two burners 5 facing in the furnace width direction are burned simultaneously. As a result, even in the region S1 between the skid beams 3 where a low temperature portion has been generated only by the flame of one burner 5, the flames of the burner 5 facing each other are concentrated so as to overlap each other, thereby blocking the radiation. The temperature rise can be obtained without any problem, and the temperature distribution in the furnace width direction can be made uniform. As a result, the amount of heat applied to the material to be heated 2 is approximately the same in the region S1 between the skid beam 3 and the region S2 between the skid beam 3 and the burner 5, and the skid beam 3 causes a bias to the lower surface of the material 2 to be heated. Heat generation can be prevented and the lower surface of the heated material 2 can be heated uniformly.

  At this time, as shown in FIG. 3, two heat storage alternating combustion burners adjacent to the side wall 4 are paired, the facing burners 5 are simultaneously burned, and combustion / non-combustion is alternately performed by the pair of adjacent burners 5. It is preferable to carry out. In this way, when the two burners 5 facing each other are burning, the two adjacent burners 5 paired with these burners 5 are in a non-burning state. Thereby, the temperature distribution around the burner 5 facing each other can be made uniform in the furnace width direction of the lower heating zone 7.

  FIG. 5 shows a front cross-sectional view of the heating furnace 1 in a state where two heated materials 2 having different widths are placed on the skid beam 3. The minimum width in which the heated material 2 can be conveyed is w1, and the maximum width in which the material 2 can be conveyed is w2. As described above, in the heating furnace 1, the heated material 2 having different widths may be continuously processed. In the present embodiment, not only in the upper heating zone 6 but also in the lower heating zone 7. However, the uniform heating is possible regardless of the width of the material 2 to be heated. This is because, in the lower heating zone 7, by the simultaneous combustion of the burner 5 facing, even in the region S1 between the skid beams 3, the temperature can be raised without producing a low temperature portion that blocks the flame radiation, This is because the temperature distribution in this region S1 and the region S2 between the skid beam 3 and the burner 5 becomes uniform. Thereby, uniform heating is possible for the entire heated material 2 having the maximum width w2 conveyed across the region S1 between the skid beam 3 and the region S2 between the skid beam 3 and the burner 5. Further, even for the material 2 to be heated having the minimum width w1 that is mostly located in the region S1 between the skid beams 3, it is possible to uniformly heat the material 2 to be heated with no difference from the material 2 to be heated having the maximum width w2. Become.

  Here, the maximum width w2 of the material 2 to be heated depends on the furnace width of the heating furnace 1, and is set slightly shorter than the furnace width. In addition, the minimum width w1 of the material 2 to be heated depends on the width between the skid beams 3 facing each other with a space therebetween. In other words, the skid beam 3 may be disposed at an interval that allows the skid beam 3 to be placed in accordance with the minimum width w1 of the material 2 to be heated.

  In the heating furnace 1 used in the present embodiment, the minimum width w1 is set short in order to transport the material to be heated 2 having various widths. For this reason, the skid beam 3 is arranged close to the center in the furnace width direction so as to be spaced apart so that the heated material 2 having the minimum width w1 can be placed thereon. Thus, even in the heating furnace 1 in which the skid beams 3 facing each other are arranged close to the center in the furnace width direction, the heated material 2 to be conveyed can be uniformly heated.

  In the operation method of the heating furnace 1 according to the present embodiment, the interval between the skid beams 3 arranged at a predetermined interval is set in the furnace so that the heated material 2 having the minimum width w1 can be placed. When the width is set to ½ or less of the width, the above-described effects are exhibited particularly. Specifically, in the case of the heating furnace 1 in which the minimum width w1 of the material to be heated 2 that can be conveyed is set to a width that is 1/2 or less of the maximum width w2, this depends on the width of the material to be heated 2. In other words, uniform heating can be achieved particularly effectively. For example, in the heating furnace 1 where the inner width of the furnace is 8 m and the maximum width w2 of the heated material 2 that can be conveyed is 7 m, the heating material 2 having the minimum width w1 of 3 m can be placed. This is a case where the skid beam 3 is disposed near the center.

  In the present embodiment, the walking beam furnace in which the skid beam 3 including the fixed skid beam 3a and the movable skid beam 3b is applied to the transfer device has been described. However, the present invention is not limited to this. For example, a heating furnace in which a fixed skid beam, a pusher, and the like are provided as a transfer device for transferring the material to be heated 2 in the furnace length direction, such as a pusher furnace.

  In this embodiment, the operation method of the heating furnace 1 which conveys the to-be-heated material 2 of various width length continuously was demonstrated. However, it is needless to say that the heated material 2 may be continuously conveyed with the same width. Furthermore, since the skid beam 3 is disposed near the center in the furnace width direction in order to use the material to be heated 2 having a short width, the disposition position of the skid beam 3 is not limited to this.

  In the present embodiment, a pair of the fixed skid beam 3a and the movable skid beam 3b are provided. However, the number of skid beams 3 is not limited to a pair.

  In the present embodiment, a pair of regenerative alternating combustion burners is used as the burner 5, but the present invention is not limited to this. A known burner used for the heating furnace 1 may be applied. Further, in the lower heating zone 7, if the burners 5 facing in the furnace width direction are simultaneously burned, the burners 5 adjacent in the furnace length direction do not have to be burned alternately.

  In the present embodiment, in the upper heating zone 6, the two burners 5 facing in the width direction are paired and burned alternately. However, the configuration of the burner 5 in the upper heating zone 6 and the combustion method are not limited to this. A known combustion method can be applied.

  In the present embodiment, the combustion method of the burner 5 is not specified. However, the combustion method of the burner 5 is a slow combustion method in which the fuel and combustion air are ignited at the burner port to inject a flame into the furnace, or the fuel and combustion air are directly injected into the furnace. A well-known combustion method such as a combustion method can be applied.

  In this embodiment, the case where the space | interval between the skid beams 3 arrange | positioned at predetermined intervals mutually was set to 1/2 or less of the furnace internal width was illustrated. However, the operation method of the heating furnace according to the present invention is such that the transfer device is arranged at the lower part of the heating furnace, and the heat input from the lower surface of the material to be heated is reduced due to the influence of the shadow of the transfer device. This is a combustion method for the furnace, and does not limit the interval between the transfer devices to ½ or less of the width in the furnace.

It is the schematic of a heating furnace which shows suitable one Embodiment of the operating method of the heating furnace concerning this invention. FIG. 2 is a state diagram showing a combustion state of the burner in the upper heating zone in the heating furnace of FIG. 1. FIG. 2 is a state diagram showing a burner combustion state in the lower heating zone in the heating furnace of FIG. 1. FIG. 2 is a front sectional view showing a combustion state of a burner in the heating furnace of FIG. 1. FIG. 2 is a front cross-sectional view illustrating a conveyance state of heated materials having different widths in the heating furnace of FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heating furnace 2 Material to be heated 3 Skid beam 3a Fixed skid beam 3b Movable skid beam 4 Side wall 5 Burner w1 Minimum width w2 Maximum width

Claims (5)

A conveying device for conveying the material to be heated in the furnace length direction is disposed at the lower part of the heating furnace, and the side surface of the lower part of the heating furnace is opposed to the furnace width direction in order to heat the lower surface of the material to be heated. A method of operating a heating furnace in which two burners are juxtaposed in the furnace length direction,
A method for operating a heating furnace, characterized in that these two burners are burned simultaneously.   The method for operating a heating furnace according to claim 1, wherein a pair of the burners adjacent to the side wall is alternately burned.   The operating method of a heating furnace according to claim 1 or 2, wherein the burner is a regenerative alternating combustion burner.   The heating furnace according to any one of claims 1 to 3, wherein the transfer device is a skid beam disposed near a center in a furnace width direction and spaced apart from each other by a predetermined distance. Operating method.   The method for operating a heating furnace according to claim 4, wherein the predetermined interval is set to ½ or less of the inner width of the furnace.

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