JP2003106774A - Rotary hearth furnace - Google Patents
Rotary hearth furnaceInfo
- Publication number
- JP2003106774A JP2003106774A JP2001295906A JP2001295906A JP2003106774A JP 2003106774 A JP2003106774 A JP 2003106774A JP 2001295906 A JP2001295906 A JP 2001295906A JP 2001295906 A JP2001295906 A JP 2001295906A JP 2003106774 A JP2003106774 A JP 2003106774A
- Authority
- JP
- Japan
- Prior art keywords
- furnace
- rotary hearth
- burner
- hearth furnace
- combustion air
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Abstract
Description
【発明の詳細な説明】
【０００１】
【発明の属する技術分野】本発明は、炉内を回転する回
転炉床の上で炭材などの還元剤を含有する酸化鉄塊成物
を加熱・還元して還元鉄塊成物を製造する回転炉床炉に
おける、バーナーおよび燃焼空気吹込孔の取り付けに関
する。
【０００２】
【従来の技術】従来の回転炉床炉におけるバーナーおよ
び燃焼空気吹込孔は、例えば、U.S.Ptent第3,452,972号
公報のFig.2、U.S.Ptent第3,503,735号公報のFig.5、特
表平11-511511号公報のFig.2に開示されているように、
炉の中心方向に向いていた。しかし、大規模な炉の場合
はバーナーおよび燃焼空気吹孔が炉の中心方向に向いて
いてもよいが、炉の巾が２ｍ未満のように小規模な炉の
場合には、以下の問題点があった。
【０００３】図１に空気比１．１のバーナーの火炎長を
示す。回転炉床で鉄鉱石または含鉄廃棄物と炭材の混合
成型物を加熱・還元する場合、鉄等の再酸化を防止する
ために、特に還元期後半の炉内雰囲気を還元雰囲気にす
る必要があり、バーナーの空気比を0.6〜0.8程度にする
必要がある。その場合、燃料の比率が高くなるので、火
炎長は空気比１.1の場合の２倍以上になる。即ち、例え
ば0.2Gcal/hのオイル焚きでの火炎長は２ｍ以上に達す
ることになる。一方、含鉄廃棄物処理量が例えば年間１
万tonの炉では、炉巾が約1.5ｍになり、従来技術のよう
にバーナーを炉の半径方向に向けて取り付けると対面す
る炉壁を高温の火炎で直接炙ることになり、耐火物の損
耗が極端に増加するという問題があった。
【０００４】この問題を解決する方法として、バーナー
の１本当りの容量を、例えば0.1Gcal/h未満に小さくし
て、空気比0.6〜0.8の時の火炎長を1.5ｍ未満にするこ
とも考えられるが、この場合、バーナー本数が極端に多
くなり、小型の炉では取り付けが実質上不可能だった。
たとえ、取り付けが可能だったとしても、バーナー燃料
および燃焼空気用の配管本数や制御弁の数が増加し、設
備費やメンテナンス費が増加するという問題点があっ
た。なお、特開平11-310832号公報の図１では、バーナ
ーを炉の半径方向から若干傾いた方向に取り付けられて
いるが、バーナーの取り付け軸は対面する炉の内側と接
触しているため、耐火物の損耗が極端に増加するという
問題点は解消されていなかった。
【０００５】
【発明が解決しようとする課題】本発明は、回転炉床炉
のバーナー取り付けに関する前述のような従来技術の問
題点を解決し、炉の巾が約2ｍ未満のような小規模な炉
でもバーナー対面の耐火物の損耗を防止でき、炉内の火
炎を円滑に循環できる回転炉床炉を提供することを課題
とする。
【０００６】
【課題を解決する手段】本発明は、回転炉床炉のバーナ
ーおよび燃焼空気吹込孔の軸線を炉の中心に向う線から
傾けて、バーナーの火炎が炉の内側および外側の耐火物
壁に接触せず、しかも、炉内の火炎を円滑に循環させる
ことにより、炉の巾が約2ｍ未満のような小規模な炉で
もバーナーが対面する耐火物の損耗を防止できる回転炉
床炉を提供するものであり、その要旨は特許請求の範囲
に記載した下記内容である。
【０００７】（１）還元剤を含有する酸化鉄塊成物を回
転炉床の上で加熱・還元して還元鉄塊成物を製造する回
転炉床炉において、該回転炉床炉の外側の壁面に取り付
けるバーナーおよび燃焼空気吹込孔の軸線が、該回転炉
床炉の内側の耐火物壁に接触しないように、該軸線を該
回転炉床炉の中心に向う線から傾けることを特徴とする
回転炉床炉。ここに、還元剤とは、粉コークスや粉石炭
などの炭材等の還元作用を有する原料をいう。酸化鉄塊
成物とは、ダストやスラジ及び鉄鉱石などの金属酸化物
を含む粉状の原料と還元剤とを混練して成型した原料を
いう。
【０００８】バーナーおよび燃焼空気吹込孔の軸線を回
転炉床炉の中心に向う線から傾ける角度は、バーナーの
火炎が回転炉床炉の内側の耐火物壁に接触しない角度と
する。これにより、バーナーの火炎が回転炉床炉の内側
の耐火物壁に接触しないので、炉の巾が約2ｍ未満のよ
うな小規模な炉でもバーナーが対面する耐火物の損耗を
防止できる。一方、バーナーおよび燃焼空気吹込孔の軸
線を回転炉床炉の中心に向う線から傾ける角度が大きす
ぎると、バーナーの火炎が回転炉床炉の外側の耐火物壁
に接触する可能性があることから、バーナーおよび燃焼
空気吹込孔の軸線と外側の耐火物壁との交点と、バーナ
ーおよび燃焼空気吹込孔との距離は、火炎長さ以上にす
ることが好ましい。
【０００９】なお、バーナーおよび燃焼空気吹込孔の軸
線を回転炉床炉の中心に向う線から傾ける向きは、炉床
が回転する方向と逆方向が好ましい。炉床の回転方向に
逆行する方向にバーナーの火炎を向ける方が、加熱効率
が良くなるからである。また、小規模な炉でも、火炎長
の長い大型のバーナーを取り付けることが可能となるの
で、バーナー本数を減らすことができ、ひいては、バー
ナー燃料および燃焼空気用の配管本数および制御弁の数
を減らすことにより、設備費やメンテナンス費を削減す
ることができる。
【００１０】
【発明の実施の形態】本発明における回転炉床炉の実施
の形態を図２に示す実施例により詳細に説明する。図２
の上段は、本発明における回転炉床炉の平断面図であ
る。装入装置１１により、酸化鉄塊成物が円形の炉床の
上に装入され、炉床が矢印の向きに一回転する間に９０
０〜１２００℃に加熱され、還元される。本実施例に用
いた酸化鉄塊成物は、アーモンドまたは枕に似た形状の
楕円形ブリケットである。
【００１１】加熱用のバーナー１および燃焼空気吹き込
み孔２は、回転炉床炉における外側の耐火物壁６の壁面
に設置されている。加熱用のバーナー１および燃焼空気
吹き込み孔２の軸線４は、回転炉床炉の中心に向かって
炉床の回転方向とは逆の方向にθ１度〜θ２度の範囲内
でずれている。θ１度以上とすることにより、バーナー
１の火炎３の中心軸４が内側の耐火物壁５に触れず耐火
物の著しい損耗を防止することができる。θ１は、外側
の耐火物壁の径：Ｄ１、内側の耐火物壁の径：Ｄ２とし
た場合、下記（Ａ）式で表わされる。
Ｓｉｎθ１＝Ｄ２／Ｄ１
∴ θ１＝Ｓｉｎ-1（Ｄ２／Ｄ１）・・・（Ａ）
また、θ２度以下とするのは、バーナー１の火炎３の中
心軸４が外側の耐火物壁６に触れず、しかも、バーナー
の火炎が炉内を円滑に循環させるためである。
【００１２】θ２は、バーナーの火炎長＝Ｌとした場
合、下記（Ｂ）式で表わされる。
Ｓｉｎ（θ１−θ２）＝（Ｄ１−Ｄ２）/２Ｌ
∴ θ２＝θ１−Ｓｉｎ−１（（Ｄ１−Ｄ２）/２Ｌ）・・・（Ｂ）
従来のように、バーナー１および燃焼空気吹き込み孔２
の軸線４を回転炉床炉の中心に向けていれば、火炎長の
短い小型のバーナーを数多く設置する必要があり、設備
費およびメンテナンス費が高くなる。
【００１３】回転炉床により加熱・還元された還元鉄塊
成物は、回転式の排出装置１０により炉外に排出され
る。なお、燃焼排ガスは排ガス孔１２により炉外に排出
される。図２の下段は、本発明における回転炉床炉の立
断面図である。回転炉床は、炉床回転軸９を中心に矢印
の方向に回転する。なお、回転炉床の天井には天井壁７
が設けられている。図３は、本発明におけるバーナーの
取り付け状況を示す詳細図である。外側の炉壁から炉の
中心に向う軸からθ度、炉床が回転する方向と逆方向に
傾けて設置する。炉床が回転する方向に逆行して火炎を
吹き付けることにより、酸化鉄塊成物の加熱効率を向上
させることができるからである。
【００１４】
【発明の効果】本発明により、回転炉床炉のバーナーお
よび燃焼空気吹込孔の軸線を炉の中心に向う線から傾け
て、バーナーの火炎が炉の内側の耐火物壁に接触せず、
火炎を炉内を円滑に循環させることにより、炉の巾が約
2ｍ未満のような小規模な炉でもバーナーが対面する耐
火物の損耗を防止できる回転炉床炉を提供することがで
きる。
【００１５】また、小規模な炉でも、火炎長の長い大型
のバーナーを取り付けることが可能となるので、バーナ
ー本数を減らすことができ、ひいては、バーナー燃料お
よび燃焼空気用の配管本数および制御弁の数を減らすこ
とにより、設備費やメンテナンス費を削減することがで
きるなど、産業上極めて有用な効果を奏する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for heating and reducing iron oxide agglomerates containing a reducing agent such as a carbon material on a rotary hearth rotating in a furnace. The present invention relates to the installation of a burner and a combustion air blowing hole in a rotary hearth furnace for producing reduced iron agglomerates. 2. Description of the Related Art Burners and combustion air injection holes in a conventional rotary hearth furnace are disclosed in, for example, FIG. 2 of US Pat. No. 3,452,972, FIG. 5 of US Pat. As disclosed in FIG. 2 of 511511,
It was facing the center of the furnace. However, in the case of a large-scale furnace, the burners and the combustion air holes may be directed toward the center of the furnace. However, in the case of a small-scale furnace having a furnace width of less than 2 m, the following problems occur. was there. FIG. 1 shows the flame length of a burner having an air ratio of 1.1. When heating and reducing a mixture of iron ore or iron-containing waste and carbon material in a rotary hearth, it is necessary to reduce the atmosphere in the furnace, especially in the latter half of the reduction period, to prevent reoxidation of iron and other materials. Yes, the air ratio of the burner needs to be about 0.6 to 0.8. In this case, the fuel ratio becomes higher, so that the flame length becomes more than twice as long as the air ratio of 1.1. That is, for example, the flame length in oil burning of 0.2 Gcal / h reaches 2 m or more. On the other hand, the amount of iron-containing waste
In the case of a 10,000 ton furnace, the furnace width is about 1.5 m. If a burner is installed in the radial direction of the furnace as in the conventional technology, the facing furnace wall is directly burned with a high-temperature flame, and the refractory is worn out. However, there was a problem that the number increased extremely. [0004] As a method of solving this problem, it is conceivable to reduce the capacity per burner to, for example, less than 0.1 Gcal / h and to make the flame length at an air ratio of 0.6 to 0.8 less than 1.5 m. However, in this case, the number of burners became extremely large, and it was practically impossible to install the furnace with a small furnace.
Even if attachment is possible, there is a problem in that the number of pipes for burner fuel and combustion air and the number of control valves increase, and equipment costs and maintenance costs increase. In FIG. 1 of JP-A-11-310832, the burner is mounted in a direction slightly inclined from the radial direction of the furnace. However, since the mounting shaft of the burner is in contact with the inside of the facing furnace, the burner is refractory. The problem of extremely increased wear of objects has not been solved. SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art relating to the installation of a burner in a rotary hearth furnace, and reduces the size of the furnace to a small scale such as a furnace width of less than about 2 m. It is an object of the present invention to provide a rotary hearth furnace capable of preventing wear of refractories facing a burner in a furnace and smoothly circulating a flame in the furnace. SUMMARY OF THE INVENTION The present invention is directed to a rotary hearth furnace in which the axes of the burner and the combustion air inlet are tilted from a line toward the center of the furnace so that the flame of the burner refractories inside and outside the furnace. A rotary hearth furnace that does not touch the walls and smoothly circulates the flame inside the furnace, thereby preventing the wear of refractories facing the burner even in a small furnace with a furnace width of less than about 2 m The gist is as described below in the claims. (1) A rotary hearth furnace for producing reduced iron agglomerates by heating and reducing an iron oxide agglomerate containing a reducing agent on a rotary hearth, The axis of the burner and the combustion air blow hole attached to the wall is inclined from a line toward the center of the rotary hearth furnace so that the axis does not contact the refractory wall inside the rotary hearth furnace. Rotary hearth furnace. Here, the term "reducing agent" refers to a raw material having a reducing action, such as carbonaceous materials such as coke breeze and pulverized coal. The iron oxide agglomerate refers to a raw material obtained by kneading a powdery raw material containing a metal oxide such as dust, sludge, ore ore, and a reducing agent. The angle of inclination of the axis of the burner and the combustion air injection hole from the line toward the center of the rotary hearth furnace is such that the flame of the burner does not contact the refractory wall inside the rotary hearth furnace. Since the flame of the burner does not come into contact with the refractory wall inside the rotary hearth furnace, it is possible to prevent wear of the refractory facing the burner even in a small-scale furnace having a width of less than about 2 m. On the other hand, if the axis of the burner and the combustion air injection hole is inclined too far from the line toward the center of the rotary hearth furnace, the flame of the burner may contact the refractory wall outside the rotary hearth furnace. Therefore, it is preferable that the distance between the intersection of the axis of the burner and the combustion air blowing hole and the outer refractory wall and the distance between the burner and the combustion air blowing hole be longer than the flame length. [0009] The direction of inclining the axis of the burner and the combustion air injection hole from the line toward the center of the rotary hearth furnace is preferably opposite to the direction in which the hearth rotates. This is because, if the flame of the burner is directed in a direction opposite to the rotation direction of the hearth, the heating efficiency is improved. In addition, since a large-sized burner having a long flame length can be installed even in a small-scale furnace, the number of burners can be reduced, and thus the number of pipes and control valves for burner fuel and combustion air can be reduced. As a result, equipment costs and maintenance costs can be reduced. An embodiment of a rotary hearth furnace according to the present invention will be described in detail with reference to an embodiment shown in FIG. FIG.
The upper section is a plan sectional view of the rotary hearth furnace of the present invention. The iron oxide agglomerate is charged by the charging device 11 onto the circular hearth, and the iron oxide agglomerate is rotated 90 times while the hearth makes one rotation in the direction of the arrow.
It is heated to 0 to 1200 ° C. and reduced. The iron oxide agglomerate used in this example is an elliptical briquette shaped like almonds or pillows. The heating burner 1 and the combustion air blowing hole 2 are installed on the outer wall of the refractory wall 6 in the rotary hearth furnace. The axis 4 of the heating burner 1 and the combustion air blowing hole 2 is shifted toward the center of the rotary hearth furnace in a direction opposite to the direction of rotation of the hearth within a range of θ1 degrees to θ2 degrees. By setting θ1 degrees or more, the central axis 4 of the flame 3 of the burner 1 does not touch the inner refractory wall 5, and remarkable wear of the refractory can be prevented. θ1 is expressed by the following equation (A), where D1 is the diameter of the outer refractory wall and D2 is the diameter of the inner refractory wall. Sin θ1 = D2 / D1∴θ1 = Sin −1 (D2 / D1) (A) The reason for setting the angle θ2 degrees or less is that the central axis 4 of the flame 3 of the burner 1 touches the outer refractory wall 6. In addition, it is because the flame of the burner circulates smoothly in the furnace. Θ2 is expressed by the following equation (B) when the flame length of the burner is L. Sin (θ1−θ2) = (D1−D2) / 2L∴θ2 = θ1−Sin−1 ((D1−D2) / 2L) (B) As in the conventional case, the burner 1 and the combustion air blowing hole 2
If the axis 4 is directed toward the center of the rotary hearth furnace, it is necessary to install many small burners having a short flame length, which increases equipment costs and maintenance costs. The reduced iron agglomerates heated and reduced by the rotary hearth are discharged out of the furnace by a rotary discharging device 10. The combustion exhaust gas is discharged outside the furnace through the exhaust gas hole 12. The lower part of FIG. 2 is a vertical sectional view of the rotary hearth furnace of the present invention. The rotary hearth rotates around the hearth rotating shaft 9 in the direction of the arrow. The ceiling of the rotary hearth has a ceiling wall 7
Is provided. FIG. 3 is a detailed view showing a mounting state of the burner according to the present invention. It is installed at an angle of θ degrees from the axis from the outer furnace wall to the center of the furnace, in a direction opposite to the direction in which the hearth rotates. This is because the efficiency of heating the iron oxide agglomerates can be improved by spraying the flame in a direction reverse to the rotation of the hearth. According to the present invention, the axes of the burner and the combustion air blow hole of the rotary hearth furnace are inclined from the line toward the center of the furnace so that the flame of the burner contacts the refractory wall inside the furnace. Not
By circulating the flame smoothly inside the furnace, the width of the furnace
It is possible to provide a rotary hearth furnace capable of preventing wear of refractories facing a burner even in a small-scale furnace of less than 2 m. [0015] In addition, a large-sized burner having a long flame length can be attached even to a small-scale furnace, so that the number of burners can be reduced. As a result, the number of piping for burner fuel and combustion air and the control valve can be reduced. By reducing the number, it is possible to reduce equipment costs and maintenance costs, and to achieve industrially extremely useful effects.
【図面の簡単な説明】
【図１】 バーナー容量と可視火炎長との関係を示す図
である。
【図２】 本発明における回転炉床炉の平断面図および
立断面図である。
【図３】 本発明におけるバーナーの取り付け状況を示
す詳細図である。
【符号の説明】
１： バーナー
２： 燃焼空気吹込み孔
３： 火炎
４： バーナーの軸線
５： 内側の耐火物壁
６： 外側の耐火物壁
７： 天井壁
８： 炉床
９： 炉床回転軸
１０：排出装置
１１：装入装置
１２：排ガス孔BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing the relationship between burner capacity and visible flame length. FIG. 2 is a plan sectional view and a vertical sectional view of a rotary hearth furnace according to the present invention. FIG. 3 is a detailed view showing a mounting state of a burner according to the present invention. [Description of Signs] 1: Burner 2: Combustion air blowing hole 3: Flame 4: Burner axis 5: Inner refractory wall 6: Outer refractory wall 7: Ceiling wall 8: Hearth floor 9: Hearth rotation Shaft 10: Discharge device 11: Charge device 12: Exhaust gas hole
───────────────────────────────────────────────────── フロントページの続き Ｆターム(参考） 3K023 DA03 DA08 DB02 DC01 3K091 AA18 BB05 BB25 CC02 CC06 EC02 EC13 4K012 DE03 DE08 4K050 AA00 BA02 CA09 CD03 ────────────────────────────────────────────────── ─── Continuation of front page F term (reference) 3K023 DA03 DA08 DB02 DC01 3K091 AA18 BB05 BB25 CC02 CC06 EC02 EC13 4K012 DE03 DE08 4K050 AA00 BA02 CA09 CD03
Claims (1)
床の上で加熱・還元して還元鉄塊成物を製造する回転炉
床炉において、該回転炉床炉の外側の壁面に取り付ける
バーナーおよび燃焼空気吹込孔の軸線が、該回転炉床炉
の内側の耐火物壁に接触しないように、該軸線を該回転
炉床炉の中心に向う線から傾けることを特徴とする回転
炉床炉。Claims 1. A rotary hearth furnace for producing reduced iron agglomerates by heating and reducing iron oxide agglomerates containing a reducing agent on a rotary hearth, wherein the rotary furnace The axis of the burner and the combustion air blow hole attached to the outer wall surface of the hearth furnace is inclined from a line toward the center of the rotary hearth furnace so that the axis does not contact the refractory wall inside the rotary hearth furnace. A rotary hearth furnace, characterized in that:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001295906A JP2003106774A (en) | 2001-09-27 | 2001-09-27 | Rotary hearth furnace |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001295906A JP2003106774A (en) | 2001-09-27 | 2001-09-27 | Rotary hearth furnace |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2003106774A true JP2003106774A (en) | 2003-04-09 |
Family
ID=19117256
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001295906A Pending JP2003106774A (en) | 2001-09-27 | 2001-09-27 | Rotary hearth furnace |
Country Status (1)
| Country | Link |
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| JP (1) | JP2003106774A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103075883A (en) * | 2012-05-31 | 2013-05-01 | 辽宁新发展耐火材料集团有限公司 | Efficient energy-saving full-automatic electric magnesium melting revolving furnace |
| JP5320517B1 (en) * | 2013-04-08 | 2013-10-23 | 新日鉄住金エンジニアリング株式会社 | Combustion apparatus, operating method thereof, and rotary hearth type heating furnace |
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2001
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103075883A (en) * | 2012-05-31 | 2013-05-01 | 辽宁新发展耐火材料集团有限公司 | Efficient energy-saving full-automatic electric magnesium melting revolving furnace |
| JP5320517B1 (en) * | 2013-04-08 | 2013-10-23 | 新日鉄住金エンジニアリング株式会社 | Combustion apparatus, operating method thereof, and rotary hearth type heating furnace |
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