JPS6036586Y2 - steel heating furnace - Google Patents

Description

【考案の詳細な説明】 本考案はスラブ、ビレット等の鋼材を目的の圧延温度ま
で均一加熱する鋼材加熱炉に関するものである。[Detailed Description of the Invention] The present invention relates to a steel heating furnace that uniformly heats steel materials such as slabs and billets to a target rolling temperature.

従来、この種の加熱炉は被熱材（鋼材）の上、下面に直
火バーナを配置した燃焼室を設け、装入側から抽出側に
向って被熱材を搬送しながら加熱を行う直火燃焼方式の
加熱炉が一般に採用されており、燃焼室でのバーナ配置
方法によってサイドバーナ、軸流バーナ、ルーフバーナ
の三方式があることが一般的に知られている。Conventionally, this type of heating furnace has a combustion chamber with direct flame burners placed above and below the material to be heated (steel material), and heats the material directly while transporting it from the charging side to the extraction side. Fire combustion type heating furnaces are generally used, and it is generally known that there are three types depending on how the burners are arranged in the combustion chamber: side burners, axial burners, and roof burners.

前者のサイドバーナ方式は炉の両側壁部にバーナを配置
する構造のため、一般に炉長方向は比較的均一な炉温分
布が得られ易いが、炉巾方向については均一な炉温分布
が得られにくいという欠点を有しており、設備的には炉
構造が簡素なため設備コストが安いという特徴を持って
いる。The former side burner method has a structure in which burners are placed on both side walls of the furnace, so it is generally easy to obtain a relatively uniform furnace temperature distribution in the furnace length direction, but it is not possible to obtain a uniform furnace temperature distribution in the furnace width direction. It has the disadvantage of being difficult to burn, and its equipment is characterized by low equipment costs due to its simple furnace structure.

これに対して、中老の軸流バーナ方式は炉の長手方向に
バーナを配置する構造のためサイドバーナ方式の場合と
は逆に、一般に炉巾方向は比較的均一な炉温分布が得ら
れ易いが、炉長方向については均一な炉温分布が得られ
にくいという欠点を有しており、設備的にもバーナの配
置上炉巾方向にノーズ部を設ける必要があるため炉床利
用率が低く、かつ設備コストが高く、作業性及び保守性
が悪いという欠点を持っている。On the other hand, the axial flow burner method used by Chuo has a structure in which the burners are arranged in the longitudinal direction of the furnace, so contrary to the case of the side burner method, a relatively uniform furnace temperature distribution is generally obtained in the width direction of the furnace. However, it has the disadvantage that it is difficult to obtain a uniform furnace temperature distribution in the furnace length direction, and in terms of equipment, it is necessary to provide a nose section in the furnace width direction due to the burner arrangement, which reduces the hearth utilization rate. It has the disadvantages of low cost, high equipment cost, and poor workability and maintainability.

一方、後者のルーフバーナ方式はその性格上、上部燃焼
室の天井炉壁にバーナを配置する構造のため、炉巾及び
炉長方向の全面にわたって比較的均一な炉温分布が得ら
れるという特徴を有しているが、他の三方式に比べてバ
ーナ本数が多くなるため一般に設備費が高く、かつバー
ナ配置の性格上、上部燃焼室のみしか適用できないとい
う欠点を有している。On the other hand, the latter roof burner method has a structure in which the burner is placed on the ceiling furnace wall of the upper combustion chamber, so it has the characteristic that a relatively uniform furnace temperature distribution can be obtained over the entire furnace width and furnace length direction. However, since the number of burners is larger than the other three methods, the equipment cost is generally high, and due to the nature of the burner arrangement, it has the disadvantage that it can only be applied to the upper combustion chamber.

又、この種の直火燃焼方式を燃焼機能面からみた場合、
バーナから供給された燃料と燃焼用空気を直接炉内（燃
焼室内）の自由空間で混合燃焼させ、その燃焼ガスの輝
炎放射、ガス放射及び炉壁放射を利用して被熱材の加熱
を行うものであるが、一般にこの種の直火燃焼方式では
バーナから供給される流体の噴出エネルギーを十分に大
きく取っても、その火炎長は精々３〜４ｍＬかならず、
加えて低負荷燃焼時にはバーナ供給流体の噴出エネルギ
ーも小さくなるため火炎の直進性が低下し、浮力による
火炎の舞上り現象や炉内ガス流れによる火炎の曲折現象
が発生するという基本的な問題を有していたため、最近
の加熱炉のごとく炉の大型化（炉巾で１０〜１５ｒｒＬ
１炉長で３０〜５０ｒｒＬ）や操業の多様化（９５０〜
１２５０℃迄の広温度範囲で均一加熱）に対しては、従
来の直火燃焼方式では十分に対処することができなかっ
た。Also, when looking at this type of direct flame combustion method from the combustion function perspective,
The fuel and combustion air supplied from the burner are mixed and burned directly in the free space inside the furnace (combustion chamber), and the material to be heated is heated using the bright flame radiation, gas radiation, and furnace wall radiation of the combustion gas. However, in general, in this type of direct combustion method, even if the ejection energy of the fluid supplied from the burner is sufficiently large, the flame length is only 3 to 4 mL at most.
In addition, during low-load combustion, the ejection energy of the burner supply fluid also decreases, which reduces the straightness of the flame, and this solves the basic problem of flame soaring due to buoyancy and flame bending due to gas flow in the furnace. Because of this, the furnace has become larger (furnace width is 10 to 15 rrL) like recent heating furnaces.
30~50rrL per furnace length) and diversification of operations (950~
Conventional direct combustion methods have not been able to adequately cope with the problem of uniform heating over a wide temperature range up to 1250°C.

又、最近は炉の大型化に伴い被熱材の搬送手段として一
般にウオーキングビーム方式を採用する傾向にあるが、
このウオーキングビーム方式では被熱材を断熱、水冷構
造の固定及び可動スキッドで支持、搬送する方式のため
、このスキッド直上にある被熱材はスキッドパイプのシ
ャドウ効果により伝熱が阻害されるため、被熱材の他の
部分に比べて加熱がされにくいという欠点を有しており
、被熱利の均一加熱のためには加熱初期の段階でこのス
キッドシャドウ部を積極的に加熱する、いわゆるピーク
温度を有した炉温分布を形成することが望ましいが、従
来の直火燃焼方式の加熱炉では任意点、即ち、スキッド
部にピーク炉温を作ることは一般的に不可能であった。In addition, recently, as furnaces have become larger, there has been a general trend to adopt a walking beam method as a means of transporting materials to be heated.
In this walking beam method, the heated material is supported and transported by a fixed and movable skid with an insulated and water-cooled structure, so the heat transfer of the heated material directly above the skid is inhibited by the shadow effect of the skid pipe. It has the disadvantage that it is difficult to heat compared to other parts of the heated material, so in order to uniformly heat the heated material, this skid shadow part must be actively heated in the early stage of heating, so-called peak heating. Although it is desirable to form a furnace temperature distribution with a certain temperature, in conventional direct combustion type heating furnaces, it is generally impossible to create a peak furnace temperature at an arbitrary point, that is, at the skid portion.

本考案は、従来の直火燃焼式加熱炉の問題点である被熱
材の均−加熱性の改善に主眼を置き、被熱材の偏熱防止
による加熱Ｔ／Ｈのアップと品質の向上を設備コストの
安いサイドバーナ方式で図るため、両端を開放端とした
放射管を炉内に複数個配し、該放射管の炉壁側管端に燃
焼装置を近設すと共に、該放射管の炉内側管端の前方に
放射管の中心軸に対し交差方向へ平板状の燃焼ガス分散
壁を設けるよう構成してなることを特徴とする鋼材加熱
炉である。This invention focuses on improving the uniform heating of the heated material, which is a problem with conventional direct-fired combustion heating furnaces, and increases heating T/H and quality by preventing uneven heat of the heated material. In order to achieve this using a side burner method with low equipment costs, a plurality of radiant tubes with both ends open are arranged in the furnace, and a combustion device is installed near the end of the radiant tube on the furnace wall side. A steel heating furnace characterized in that a flat combustion gas dispersion wall is provided in front of an end of the furnace inner tube in a direction crossing the central axis of the radiant tube.

以下、第１図から第７図に従って本考案の一実施例を説
明する。An embodiment of the present invention will be described below with reference to FIGS. 1 to 7.

図において１は耐火断熱性と機密性を有した炉壁、２は
炉壁１の天井部の炉長方向と炉巾方向に複数個配置され
たルーフバーナ、３は炉壁１の炉長方向の下部両側壁に
配置されたサイドバーナであり、４は加熱炉を各燃焼室
に仕切るための仕切壁、５は被熱材、即ち鋼材、６は予
熱帯、７は加熱帯、８は均熱帯である。In the figure, 1 is a furnace wall with fireproof insulation and airtightness, 2 is a plurality of roof burners arranged in the furnace length direction and furnace width direction on the ceiling of the furnace wall 1, and 3 is a furnace wall on the furnace wall 1 in the furnace length direction. Side burners are placed on both lower side walls, 4 is a partition wall for partitioning the heating furnace into each combustion chamber, 5 is a material to be heated, that is, steel, 6 is a preheating zone, 7 is a heating zone, and 8 is a soaking zone. It is.

９は被熱材５を支持するための固定スキッド、１０は被
熱材５を搬送するための可動スキッドであり水冷スキッ
ドパイプの外面は断熱構造となっている。9 is a fixed skid for supporting the heated material 5; 10 is a movable skid for conveying the heated material 5; the outer surface of the water-cooled skid pipe has a heat insulating structure.

１１はサイドバーナ３の炉内側先端部に間隙を設けて配
置された所要長さの耐熱性と熱伝導性を有した円筒状の
放射管、１２は放射管１１の支柱壁、１３は放射管より
放出された燃焼ガスを炉内へ分散供給するための耐熱性
を有した平板状の燃焼ガス分散壁であり、通常、この燃
焼ガス分散壁１３の巾は放射管１１から噴出された燃焼
ガスの噴流直径以上とし、高さは噴流の拡がり範囲内で
加熱目的に応じて決定される。Reference numeral 11 denotes a cylindrical radiant tube having a required length and heat resistance and thermal conductivity, which is disposed with a gap at the tip inside the furnace of the side burner 3, 12 is a support wall of the radiant tube 11, and 13 is a radiant tube. This is a heat-resistant flat plate-shaped combustion gas distribution wall for dispersing and supplying the combustion gas emitted from the radiator tube 11 into the furnace. The height of the jet is determined according to the purpose of heating within the spread range of the jet.

又、図中の破線による矢印はルーフバーナ２からの燃焼
ガス流れを、実線による矢印はサイドバーナ３から炉内
へ分散供給される燃焼ガス流れを示したものである。Further, the broken line arrows in the figure indicate the flow of combustion gas from the roof burner 2, and the solid line arrows indicate the flow of combustion gas distributed and supplied from the side burner 3 into the furnace.

次に本考案の作動機能について説明する。Next, the operating function of the present invention will be explained.

加熱炉内に装入された被熱材５は被熱材５の支持、搬送
装置である固定スキッド９及び可動スキッド１０によっ
て装入側の予熱帯６から抽出側の均熱帯８に向って搬送
される間に被熱材５の上面はルーフバーナ２により、被
熱材５の下面はサイドバーナ３により加熱が行われる。The material to be heated 5 charged into the heating furnace is transported from the preheating zone 6 on the charging side to the soaking zone 8 on the extraction side by a fixed skid 9 and a movable skid 10, which are supporting and conveying devices for the material to be heated 5. During this period, the upper surface of the heat-receiving material 5 is heated by the roof burner 2, and the lower surface of the heat-receiving material 5 is heated by the side burner 3.

この場合、加熱炉の下部はサイドバーナ３の先端に放射
管１１を配備する構造のため、サイドバーナ３から供給
された燃料と燃焼用空気は放射管１１内で混合燃焼が行
われるため従来の直火燃焼方式に比べて浮力や炉内ガス
流れの影響を受けることがないため燃焼量の多少に関係
なく炉内の目的位置まで燃焼ガスを搬送することが可能
である。In this case, since the lower part of the heating furnace has a structure in which the radiant tube 11 is provided at the tip of the side burner 3, the fuel and combustion air supplied from the side burner 3 are mixed and burned within the radiant tube 11, which is different from the conventional method. Compared to the direct combustion method, it is not affected by buoyancy or the gas flow in the furnace, so it is possible to transport the combustion gas to the target position in the furnace regardless of the amount of combustion.

更に、この燃焼ガスは放射管１１の炉内側開放端から炉
内に放出されるが、放射管１１の炉内側管端の前方に所
要形状の燃焼ガス分散壁１３を配置しであるため、この
燃焼ガス分散壁１３に衝突した燃焼ガスは放射管１１側
の炉内へ分散供給されるため燃焼ガス分散壁１３の前方
にピーク点を有した炉温分布を形成することが可能であ
る。Furthermore, this combustion gas is discharged into the furnace from the open end of the radiant tube 11 inside the furnace, but since the combustion gas dispersion wall 13 of a desired shape is disposed in front of the end of the radiant tube 11 inside the furnace, this Since the combustion gas that has collided with the combustion gas distribution wall 13 is distributed and supplied into the furnace on the radiant tube 11 side, it is possible to form a furnace temperature distribution having a peak point in front of the combustion gas distribution wall 13.

この結果、被熱材５の加熱が行われにくい固定スキッド
９と可動スキッド１０間の、いわゆるスキッドシャドウ
部を積極的に加熱することが可能となり、９５０〜１２
５０°Ｃという広温度範囲にわたって被熱材５の均一加
熱が安定して行なえるという特徴を有している。As a result, it becomes possible to actively heat the so-called skid shadow area between the fixed skid 9 and the movable skid 10, where it is difficult to heat the heated material 5.
It has the characteristic that uniform heating of the heated material 5 can be performed stably over a wide temperature range of 50°C.

次に本考案の効果を燃焼実験炉（高１．８×巾３．０×
長６．４ｙｎ、）で確認した結果を例示する。Next, we will demonstrate the effect of this invention in a combustion experimental furnace (height 1.8 x width 3.0 x
The results confirmed with the length 6.4yn,) are illustrated below.

実験は本考案の効果を確認するため炉出方向に１．７ｍ
のピッチで燃焼量１５０万Ｋｃａｌ ／ ｈ （７）バ
ーナを２本取付け、被熱材５による奪熱を模擬するため
天井炉壁には水冷奪熱管を配し、燃焼としてはコークス
炉ガス、燃焼用空気としては、３００℃の熱風を用い空
気比１．１の共通条件のもとで、従来の直火燃焼方式と
本考案の燃焼方式の比較を行った結果を第５図から第７
図に示す。The experiment was conducted at a distance of 1.7 m in the direction of exit from the furnace in order to confirm the effectiveness of this invention.
Burning amount: 1,500,000 Kcal/h (7) Two burners are installed, and a water-cooled heat-absorbing tube is placed on the ceiling furnace wall to simulate heat extraction by the heat-receiving material 5. Figures 5 to 7 show the results of a comparison between the conventional direct flame combustion method and the combustion method of the present invention under the common condition of using hot air at 300°C as the air for use and an air ratio of 1.1.
As shown in the figure.

第５図は従来の直火燃焼方式の一例として、実炉での炉
出方向の温度分布特性が最も優れているとの評価が高い
ガス二流式サイドバーナの炉温分布の測定例である。FIG. 5 is an example of measuring the furnace temperature distribution of a gas two-flow side burner, which is highly rated as having the best temperature distribution characteristics in the exit direction in an actual furnace, as an example of a conventional direct-fire combustion system.

又、第６図は放射管１１を単独で使用した場合の炉温分
布の測定例であり、バーナとしてはノズルミックスタイ
プを使用、放射管１１としては５００φのＳｉＣチュー
ブを４．８ｒｒＬの長で使用した結果である。Furthermore, Fig. 6 shows an example of measuring the furnace temperature distribution when the radiant tube 11 is used alone; a nozzle mix type is used as the burner, and the radiant tube 11 is a 500φ SiC tube with a length of 4.8 rrL. This is the result of using it.

第７図は本考案の放射管１１と燃焼ガス分散壁１３を組
合せた場合の炉温分布の測定例であり、バーナは第６図
と同じものを使用し、放射管１１は直径が５００φで長
さが１．６ｍのＳｉＣチューブをバーナから２５０Ｔｒ
ｒｒｆＬの間隙を設けて配置腰放射管１１の炉内側前方
１ｍの所に巾が９２０ｒｆｒＩｎで高さが放射管１１の
中心高さと同じ７８０ｍの燃焼ガス分散壁１３を配した
場合の結果である。Fig. 7 shows an example of measuring the furnace temperature distribution when the radiant tube 11 of the present invention and the combustion gas distribution wall 13 are combined.The burner used is the same as in Fig. 6, and the radiant tube 11 has a diameter of 500φ. A SiC tube with a length of 1.6m is connected to a 250Tr from a burner.
This is the result when a combustion gas distribution wall 13 with a width of 920 rfrIn and a height of 780 m, which is the same as the center height of the radiant tube 11, is placed 1 m in front of the inner side of the furnace of the radiant tube 11 arranged with a gap of rrfL.

第５図から第７図は横軸にバーナからの距離を、縦軸に
は炉温をバーナ長方向の各断面での測定温度（Ｔ）ＳＥ
Ｃとバーナ長方向の平均温度（’Ｉ”） ＡＶＥとの差
で示したものであり、燃焼量２０〜１００％の範囲で実
験た結果を図中の斜線範囲で表示したものである。In Figures 5 to 7, the horizontal axis represents the distance from the burner, and the vertical axis represents the furnace temperature (T) SE
It is shown as the difference between C and the average temperature ('I'') in the burner length direction AVE, and the results of experiments in the range of combustion amount of 20 to 100% are shown in the shaded range in the figure.

この結果、従来の直火燃焼方式ではバーナから約１．５
ｍの所に火炎のピーク温度があり、それより先では急速
に炉温の低下が見られる、いわゆるバーナ測高の温度傾
向を示すため炉巾が広い大型炉では炉中央部の炉温か低
くなり被熱材５の偏熱が大きくなることを示している。As a result, in the conventional direct combustion method, approximately 1.5
There is a peak flame temperature at m, and a rapid drop in furnace temperature is seen beyond that point, which is the so-called temperature trend of burner height measurement.In large furnaces with a wide furnace width, the furnace temperature in the center of the furnace is lower. This indicates that the uneven heat of the heated material 5 increases.

これに対して、放射管燃焼方式では燃焼量にほとんど関
係なく、バーナ長方向に対して略角−な炉温分布が得ら
れるということを示している。In contrast, the radiant tube combustion method shows that a furnace temperature distribution approximately at an angle to the burner length direction can be obtained, almost regardless of the combustion amount.

第７図の実験結果は燃焼ガス分散壁を放射管の中心軸と
直角に配設した場合について示したが、角度を変えるこ
とにより炉温ピーク点位置を変更させることが可能であ
る。Although the experimental results shown in FIG. 7 are for the case where the combustion gas distribution wall is disposed perpendicular to the central axis of the radiant tube, it is possible to change the position of the furnace temperature peak point by changing the angle.

又、本考案の放射管と燃焼ガス分散壁を組合せた場合は
燃焼ガス分散壁の直前にピーク点を有した炉温分布を形
成することが可能であり、放射管の長さ及び燃焼ガス分
散壁の位置によって炉温ピーク点を、燃焼ガス分散壁の
高さ、取付角度により炉温ピーク値を自由に選択するこ
とができることを示している。Furthermore, when the radiant tube of the present invention is combined with the combustion gas distribution wall, it is possible to form a furnace temperature distribution with a peak point just before the combustion gas distribution wall, and the length of the radiant tube and the combustion gas distribution can be This shows that the furnace temperature peak point can be freely selected by the position of the wall, and the furnace temperature peak value can be freely selected by the height and installation angle of the combustion gas distribution wall.

以上、述べた様に本考案の鋼材加熱炉は従来の直火燃焼
式加熱炉の問題であったバーナ長方向の炉温分布の改善
を図るため、直火燃焼バーナの先端に放射管と燃焼ガス
分散壁を組合せて配置することにより、炉内の所要位置
に所要のピーク温度を有した炉温分布を形成することが
可能なため、加熱炉で被熱材の偏熱原因となるスキッド
シャドウ部を積極的に加熱することが可能であり、被熱
材の均一加熱、即ち、偏熱の防止により加熱Ｔ／Ｈのア
ップと品質の向上が設備コストの安いサイドバーナ方式
で可能という特徴を有した鋼材加熱炉である。As mentioned above, the steel reheating furnace of the present invention has a radiant tube installed at the tip of the direct-fired combustion burner in order to improve the furnace temperature distribution in the burner length direction, which was a problem with conventional direct-fired combustion type reheating furnaces. By arranging gas dispersion walls in combination, it is possible to form a furnace temperature distribution with the required peak temperature at the desired position in the furnace, thereby eliminating skid shadows that cause uneven heat of the heated material in the heating furnace. The side burner method has the advantage of being able to heat the heated material evenly, that is, by preventing uneven heat, increasing the heating T/H and improving quality using the side burner method, which has low equipment costs. This is a steel heating furnace with

【図面の簡単な説明】[Brief explanation of the drawing]

図面において第１図は本考案の鋼材加熱炉の縦断面図、
第２図は第１図のＩ−Ｉ線における側断面図、第３図は
第２図の■−■線からみた炉下部における一部分の平面
図、第４図は放射管と支柱壁の拡大断面図、第５図は従
来の直火燃焼方式における炉内温度分布の測定例の図、
第６図は放射管燃焼方式における炉内温度分布の測定例
の図、第７図は本考案の放射管と燃焼ガス分散壁を組合
せた場合の炉温分布の測定例を示す図である。 １は炉壁、２はルーフバーナ、３はサイドバーナ、４は
仕切壁、５は被熱材（鋼材）、６は予熱帯、７は加熱帯
、８は均熱帯、９は固定スキッド、１０は可動スキッド
、１１は放射管、１２は支柱壁、１３は燃焼ガス分散壁
。In the drawings, FIG. 1 is a longitudinal cross-sectional view of the steel heating furnace of the present invention;
Figure 2 is a side sectional view taken along line I-I in Figure 1, Figure 3 is a plan view of a portion of the lower part of the reactor seen from line ■-■ in Figure 2, and Figure 4 is an enlarged view of the radiation tube and support wall. A cross-sectional view, and Figure 5 is a diagram of an example of measuring the temperature distribution inside the furnace in a conventional direct-fire combustion method.
FIG. 6 is a diagram showing an example of measuring the temperature distribution in the furnace in the radiant tube combustion method, and FIG. 7 is a diagram showing an example of measuring the furnace temperature distribution when the radiant tube of the present invention and the combustion gas distribution wall are combined. 1 is a furnace wall, 2 is a roof burner, 3 is a side burner, 4 is a partition wall, 5 is a heated material (steel material), 6 is a preheating zone, 7 is a heating zone, 8 is a soaking zone, 9 is a fixed skid, 10 is a A movable skid, 11 a radiation tube, 12 a support wall, and 13 a combustion gas distribution wall.

Claims (1)

【実用新案登録請求の範囲】[Scope of utility model registration request] 両端を開放した放射管を炉内に複数個配し、該放射管の
炉壁側管端に燃焼装置を近接すると共に、該放射管の炉
内側管端の前方に放射管の中心軸に対し交差方向へ平板
状の燃焼ガス分散壁を設けるよう構成してなることを特
徴とする鋼材加熱炉。A plurality of radiant tubes with both ends open are disposed in the furnace, and a combustion device is placed close to the end of the radiant tube on the furnace wall side, and a combustion device is placed in front of the end of the radiant tube on the inner side of the radiant tube relative to the central axis of the radiant tube. A steel heating furnace characterized in that it is configured such that a flat plate-shaped combustion gas distribution wall is provided in a cross direction.