JPH0861613A - Low nox burner - Google Patents

Abstract

PURPOSE: To compact flame with a simple structure by a method wherein combustion air is supplied by dividing it into primary air, injected out of a primary flame keeping plate, and secondary air, injected out of a secondary air injection port at the tip end of a gap between a primary cone and a secondary cone while the secondary air is injected so as to have the shape of a hollow cone. CONSTITUTION: Combustion air is supplied to a burner unit from a fan through an air box 10 after dividing it into primary air and secondary air. The primary air is supplied from a primary air introducing port 3 into a combustion chamber through a gap of a primary flame keeping plate 4 bia the inside of a primary air tube 2 while secondary air enters from the rear end of a secondary air tube 6 and is supplied into the combustion chamber from a secondary air injecting port 8 through a tapered gap between a primary cone 5 and a secondary cone 7 bia a gap between the primary air tube 2 and the secondary air tube 6. The secondary air stream 9 forms a hollow cone shape, having the thickness T and an injection angle 61 while the shape of the flame can be controlled by changing the injection angle 81 whereby the burner can be applied for a boiler having a high combustion chamber load.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明はボイラ及び燃焼炉に利用
する低ＮＯｘバ−ナに関するものである。BACKGROUND OF THE INVENTION The present invention relates to a low NOx burner used in boilers and combustion furnaces.

【０００２】[0002]

【従来技術】近年、ＮＯｘ規制の強化に伴いバ−ナによ
るＮＯｘ発生の抑制はガス燃料だけでなく油燃料でも不
可欠なものになってきている。ＮＯｘの生成を抑制する
主な方法は（１）火炎温度を下げる、（２）酸素濃度を
下げる、（３）高温部での空気の滞留時間を短縮させる
ことである。油燃料を使用した低ＮＯｘバ−ナでは蒸気
又は水噴射で火炎温度を下げたり、又は、排ガス再循環
法で酸素濃度を下げてＮＯｘの生成を抑制する場合が多
い。2. Description of the Related Art In recent years, with the tightening of NOx regulations, suppression of NOx generation by burners has become indispensable not only for gas fuel but also for oil fuel. The main methods of suppressing the generation of NOx are (1) lowering the flame temperature, (2) lowering the oxygen concentration, and (3) shortening the residence time of air in the high temperature part. In a low NOx burner using oil fuel, it is often the case that the flame temperature is lowered by steam or water injection or the oxygen concentration is lowered by an exhaust gas recirculation method to suppress NOx generation.

【０００３】しかしながら、これらの方法は装置が複雑
で配管が必要となりコストアップとなる。また、蒸気噴
射の場合は熱効率の低下を伴い、排ガス再循環はドラフ
トの影響により循環量が変動し安定性が悪い等の欠点が
ある。However, these methods require complicated piping and require piping, resulting in an increase in cost. Further, in the case of steam injection, there is a drawback in that the thermal efficiency is lowered, and the exhaust gas recirculation has poor stability because the circulation amount fluctuates due to the influence of the draft.

【０００４】最近のボイラは小型化され燃焼室負荷が３
００万Ｋｃａｌ／Ｈ・ｍ³を超えるものもある。このよ
うに燃焼室負荷の高いボイラに適用するバ−ナは、燃焼
室へのマッチングを満足させながら低ＮＯｘ化を実現し
なければならない。現在、実用化されている低ＮＯｘバ
−ナは２段燃焼法、分割火炎法、薄膜火炎法、自己排ガ
ス再循環法等を単独又は複数組み合わせているものが殆
どである。Recent boilers are downsized and the load on the combustion chamber is 3
Some exceed, 000,000 Kcal / H · m ³ . Thus, the burner applied to the boiler having a high load in the combustion chamber must realize low NOx while satisfying the matching with the combustion chamber. Currently, most of the low NOx burners that have been put into practical use are those that use a two-stage combustion method, a split flame method, a thin film flame method, a self-exhaust gas recirculation method, etc. alone or in combination.

【０００５】図６は実開平６−３０６１８号公報に開示
された、２段燃焼と火炎分割を組み合わせてなる低ＮＯ
ｘバ−ナの縦断面を示す図である。中心部に噴霧式ノズ
ル６１、その外側に１次空気パイプ６２、更にその外側
に燃焼筒６９を配置している。噴霧式ノズル６１の前方
には１次空気６４を噴出させる１次保炎板６３を設け、
１次空気パイプ６２と燃焼筒６９との間の前方（後流）
には該１次空気パイプ６２の外周に設けた２次保炎板６
５が配置されている。該２次保炎板６５の外周には凹状
の切欠きを設け、燃焼筒６９との間に２次空気噴出口７
５が形成されている。FIG. 6 shows a low NO combination of two-stage combustion and flame division disclosed in Japanese Utility Model Laid-Open No. 6-30618.
It is a figure which shows the vertical cross section of x burner. A spray nozzle 61 is arranged at the center, a primary air pipe 62 is arranged outside thereof, and a combustion cylinder 69 is arranged outside thereof. A primary flame holding plate 63 for ejecting primary air 64 is provided in front of the spray nozzle 61,
Forward (backward) between the primary air pipe 62 and the combustion tube 69
Is a secondary flame holding plate 6 provided on the outer circumference of the primary air pipe 62.
5 are arranged. A concave notch is provided on the outer periphery of the secondary flame holding plate 65, and the secondary air jet port 7 is provided between the secondary flame holding plate 65 and the combustion cylinder 69.
5 is formed.

【０００６】燃料油７１は燃料供給口より供給され、空
気６８は空気入口より調節弁７２を介して供給される。
二流体噴霧式では蒸気７０が供給口より供給され燃焼筒
６９の中で空気と混合され１次空気パイプ６２及び、２
次保炎板６５に供給される。燃料油７１は噴霧式ノズル
６１から噴霧され、前記空気と蒸気の混合気体と共に１
次保炎板６３に設けられた放射状のスリットから噴射さ
れ分割された火炎となって燃焼する。２次保炎板６５の
周囲には燃焼筒６９との間に６〜８個の噴出口７５が設
けられ前記空気と蒸気の混合気体が前記分割された火炎
に供給される。Fuel oil 71 is supplied from a fuel supply port, and air 68 is supplied from an air inlet via a control valve 72.
In the two-fluid atomization type, steam 70 is supplied from the supply port and mixed with air in the combustion cylinder 69 so that the primary air pipes 62 and 2
It is then supplied to the flame holding plate 65. The fuel oil 71 is sprayed from the spray nozzle 61, and is mixed with the mixed gas of air and steam to
The flame is jetted from the radial slits provided on the next flame holding plate 63 and divided into flames to be burned. Around the secondary flame stabilizing plate 65, 6 to 8 jets 75 are provided between the secondary flame holding plate 65 and the combustion cylinder 69, and the mixed gas of air and steam is supplied to the divided flame.

【０００７】[0007]

【発明が解決しようとする課題】しかしながら、上記実
開平６−３０６１８号公報に開示された低ＮＯｘバ−ナ
は２段燃焼と火炎分割の組合せであるが、火炎外側の自
己再循環効果を主体とするために比較的燃焼室寸法の大
きいボイラには効果があるが燃焼室負荷の高いボイラへ
の適用には限界がある等の問題がある。However, although the low NOx burner disclosed in Japanese Utility Model Laid-Open No. 6-30618 is a combination of two-stage combustion and flame splitting, it mainly has a self-recirculation effect on the outside of the flame. Therefore, it is effective for a boiler having a relatively large combustion chamber size, but there is a problem that there is a limit to application to a boiler having a high combustion chamber load.

【０００８】また特開平０３−１９１２０２号公報に開
示されたもののように、フロントプレ−トにより薄膜火
炎を形成させる方法もあるが、この方法はガス燃焼に限
定され油燃焼には適用出来ないと云う問題があった。There is also a method of forming a thin film flame by a front plate as disclosed in Japanese Patent Laid-Open No. 03-191202, but this method is limited to gas combustion and cannot be applied to oil combustion. There was a problem to say.

【０００９】本発明は上述の点に鑑みてなされたもの
で、上記問題点を除去し、簡単な構造で火炎をコンパク
トにまとめ燃焼室負荷の高いボイラにも適用可能な低Ｎ
Ｏｘバ−ナを提供することを目的とする。The present invention has been made in view of the above-mentioned problems, and eliminates the above-mentioned problems, compacts flames with a simple structure, and can be applied to a boiler having a high combustion chamber load.
The purpose is to provide an Ox burner.

【００１０】[0010]

【課題を解決するための手段】上記課題を解決するため
本発明は、中央部に燃料噴霧ノズルを配置し、その外周
より燃焼用空気を供給する構成の低ＮＯｘバ−ナにおい
て、図１に示すように、燃料噴霧ノズル１の外側に１次
空気筒２を配設すると共に、該燃料噴霧ノズル１の先端
近傍に位置し、且つ該１次空気筒２の先端に１次保炎板
４を取り付け、１次空気筒の外側に２次空気筒６を配設
し、１次保炎板４に前方に円錐状に広がる１次コ−ン５
を設けると共に、該１次コ−ン５の外側で且つ２次空気
筒６の先端から前方に円錐状に広がる２次コ−ン７を設
け、燃焼用空気を１次空気筒２の内側を通過させ１次保
炎板４より噴出する１次空気と、２次空気筒と１次空気
筒の間を経由し１次コ−ンと２次コ−ンとの隙間を通り
その先端の２次空気噴射口８より噴射する２次空気とに
分けて供給し、該２次空気を中空円錐状に噴出すること
を特徴とする。In order to solve the above problems, the present invention is directed to a low NOx burner having a structure in which a fuel spray nozzle is arranged in the central portion and combustion air is supplied from the outer periphery of the fuel spray nozzle. As shown, the primary air cylinder 2 is arranged outside the fuel spray nozzle 1, and the primary flame holding plate 4 is located near the tip of the fuel spray nozzle 1 and at the tip of the primary air cylinder 2. The secondary air cylinder 6 is attached to the outside of the primary air cylinder, and the primary cone 5 is formed on the primary flame holding plate 4 and spreads forward in a conical shape.
In addition to the above, a secondary cone 7 is provided outside the primary cone 5 and conically spreads forward from the tip of the secondary air cylinder 6, and combustion air is provided inside the primary air cylinder 2. The primary air passing through and ejected from the primary flame stabilizing plate 4 passes through the gap between the primary cone and the secondary cone through the space between the secondary air cylinder and the primary air cylinder. It is characterized in that the secondary air is supplied separately from the secondary air jetted from the secondary air jet port 8 and the secondary air is jetted in a hollow conical shape.

【００１１】また、１次コ−ン５と２次コ−ン７の隙間
の先端の２次空気噴出口８は、図３（Ｂ）に示すよう
に、開口部と閉塞部を分割配置した構成であることを特
徴とする。Further, as shown in FIG. 3 (B), the secondary air ejection port 8 at the tip of the gap between the primary cone 5 and the secondary cone 7 has an opening portion and a closed portion arranged separately. It is characterized by being a configuration.

【００１２】[0012]

【作用】本発明は上記構成を採用することにより、燃料
噴霧ノズル１から適正な粒子径で噴霧された燃料は、１
次空気筒２の１次空気導入口３から供給される全空気量
の１０〜３０％の１次空気と混合され燃焼するが、酸素
濃度不足の状態で燃焼するため火炎温度は低く維持され
る。同時に１次コ−ン５及び２次コ−ン７のテ−パ状の
隙間を経由し２次空気噴射口８から高速（２０〜４０ｍ
／ｓ）で噴射される２次空気は中空円錐状を形成するの
で、１次燃焼後の燃焼ガス及び未燃ガスはこの高速２次
空気流９に巻き込まれながら徐々に燃焼し大きなモ−メ
ンタムを持った薄膜火炎流１３（図２参照）が形成され
る。According to the present invention, by adopting the above structure, the fuel atomized from the fuel atomizing nozzle 1 with an appropriate particle size is 1
The primary air is supplied from the primary air inlet 3 of the secondary air cylinder 2 and burns by mixing with 10% to 30% of the total amount of primary air, but the flame temperature is kept low because it burns in a state of insufficient oxygen concentration. . At the same time, it passes through the taper-shaped gap of the primary cone 5 and the secondary cone 7 from the secondary air injection port 8 at a high speed (20 to 40 m).
/ S), the secondary air injected forms a hollow conical shape, so that the combustion gas and unburned gas after the primary combustion are gradually burned while being entrained in this high-speed secondary air flow 9 and have a large momentum. A thin film flame flow 13 (see FIG. 2) is formed.

【００１３】大きなモ−メンタムを持った２次空気流９
及び薄膜火炎流１３には燃焼ガスや未燃ガスが巻き込ま
れ薄膜火炎流１３の内と外に燃焼ガスの自己排ガス再循
環流１４、１５が発生し、一般的な拡散燃焼に比べて局
部的に高温度になることはなく火炎温度は低く抑えられ
ＮＯｘの発生を低減させる。Secondary air flow 9 with large momentum
In addition, the combustion gas and the unburned gas are entrained in the thin film flame flow 13, and the self-exhaust gas recirculation flows 14 and 15 of the combustion gas are generated inside and outside the thin film flame flow 13, which are localized compared with general diffusion combustion. The flame temperature does not become too high and the flame temperature is suppressed to a low level, which reduces NOx generation.

【００１４】また、前記１次コ−ン５と前記２次コ−ン
７の隙間の先端部の２次空気噴射口８を開口部８ａと閉
塞部８ｂに分割配置したことにより２次空気の濃淡によ
り分割火炎が発生するので更にＮＯｘの発生は低減され
る。Further, the secondary air injection port 8 at the tip of the gap between the primary cone 5 and the secondary cone 7 is divided into the opening 8a and the closing portion 8b, so that the secondary air is generated. Since divided flames are generated depending on the light and shade, the generation of NOx is further reduced.

【００１５】また、上記構成の低ＮＯｘバ−ナをボイラ
１１に適用する場合には、ボイラの燃焼室１２の形状に
合わせて２次空気流９の噴出角度θ１を決定することに
より、火炎が纏まり煤の発生が少ない安定した燃焼が可
能となる。Further, when the low NOx burner having the above-mentioned configuration is applied to the boiler 11, the flame is generated by determining the ejection angle θ1 of the secondary air flow 9 in accordance with the shape of the combustion chamber 12 of the boiler. Stable combustion with less generation of soot is possible.

【００１６】[0016]

【実施例】以下、本発明の一実施例を図面に基づいて詳
細に説明する。図１は本発明の低ＮＯｘバ−ナの縦断面
を示す図である。図示するように、本発明の低ＮＯｘバ
−ナは、風箱１０の中央部に燃料（油）を噴霧する燃料
噴霧ノズル１が配置され、該燃料噴霧ノズル１の外側に
１次空気筒２、その外側に２次空気筒６、１次空気筒２
の先端に１次保炎板４、該１次保炎板４の前方に１次コ
ーン５、該１次コーン５の外側に２次コーン７がそれぞ
れ配設された構造である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a view showing a vertical section of a low NOx burner of the present invention. As shown in the figure, in the low NOx burner of the present invention, a fuel spray nozzle 1 for spraying fuel (oil) is arranged in the center of a wind box 10, and a primary air cylinder 2 is provided outside the fuel spray nozzle 1. , The secondary air cylinder 6 and the primary air cylinder 2 on the outside thereof
A primary flame holding plate 4, a primary cone 5 in front of the primary flame holding plate 4, and a secondary cone 7 outside the primary cone 5.

【００１７】１次空気筒２には後部に１次空気導入口３
が設けられ、２次空気筒６の後端は風箱１０内に開放さ
れている。１次コーン５は前方に円錐状に広がる形状で
後端が１次保炎板４に取り付けられている。２次コーン
７は前方に円錐状に広がる形状で後端が２次空気筒６の
先端に接続されている。１次コーン５と２次コーン７の
間隙はその断面が後方が広く前方が狭い楔状である。The primary air cylinder 2 has a primary air inlet 3 at the rear thereof.
Is provided, and the rear end of the secondary air cylinder 6 is opened in the wind box 10. The primary cone 5 has a shape that spreads forward in a conical shape, and its rear end is attached to the primary flame holding plate 4. The secondary cone 7 has a shape that spreads forward in a conical shape, and its rear end is connected to the front end of the secondary air cylinder 6. The cross section of the gap between the primary cone 5 and the secondary cone 7 is wedge-shaped with a wide rear and a narrow front.

【００１８】燃焼用空気は送風機（図示せず）から風箱
１０を経由しバ−ナ部で１次空気と２次空気に分けて供
給される。１次空気は１次空気導入口３から１次空気筒
２の内側を経由し１次保炎板４の間隙から燃焼室内に供
給され、２次空気は２次空気筒６の後端から流入し、１
次空気筒２と２次空気筒６の間を経由し１次コ−ン５と
２次コ−ン７の断面がテ−パ状に設定された隙間を経由
し２次空気噴霧口８より燃焼室に供給される。なお、１
６は燃料噴霧ノズル１から噴霧される燃料に着火させる
着火装置である。Combustion air is supplied from a blower (not shown) through a wind box 10 in a burner section so as to be divided into primary air and secondary air. The primary air is supplied from the primary air inlet 3 through the inside of the primary air cylinder 2 into the combustion chamber through the gap between the primary flame holding plates 4, and the secondary air flows in from the rear end of the secondary air cylinder 6. Then 1
From the secondary air spray port 8 via the gap between the secondary air cylinder 2 and the secondary air cylinder 6 and the cross section of the primary cone 5 and the secondary cone 7 set in a taper shape. Supplied to the combustion chamber. 1
An ignition device 6 ignites the fuel sprayed from the fuel spray nozzle 1.

【００１９】上記１次保炎板４は旋回式でも多孔式でも
効果は略同等であるが、１次コ−ン５の内部に付着しや
すい煤を防止するためには旋回式が望ましい。また、１
次コ−ン５と２次コ−ン７の隙間から噴出する２次空気
流９は厚さＴで噴出角度θ１の中空円錐状になり、噴出
角度θ１を変化させることにより火炎形状をコントロ−
ルし燃焼室１２の形状に適合させることが可能である。The above-mentioned primary flame holding plate 4 has substantially the same effect whether it is a swirl type or a porous type, but the swirl type is preferable in order to prevent soot which tends to adhere to the inside of the primary cone 5. Also, 1
The secondary airflow 9 ejected from the gap between the secondary cone 5 and the secondary cone 7 has a hollow cone shape with a thickness T and an ejection angle θ1, and the flame shape is controlled by changing the ejection angle θ1.
The shape of the combustion chamber 12 can be adjusted.

【００２０】バルブ１７を通って燃料噴霧ノズル１に供
給され、その先端から適正な粒子径で噴霧された燃料
は、１次空気導入口３から供給される全空気量の１０〜
３０％の１次空気と混合し燃焼するが、酸素濃度不足の
状態で燃焼するため火炎温度は低く維持される。同時に
１次コ−ン５及び２次コ−ン７のテ−パ状の隙間を経由
し２次空気噴射口８から高速（２０〜４０ｍ／ｓ）で供
給される２次空気は中空円錐状を形成するので、１次燃
焼後の燃焼ガス及び未燃ガスは高速の２次空気流９に巻
き込まれながら徐々に燃焼し薄膜火炎流１３（図２参
照）を形成する。The fuel, which is supplied to the fuel spray nozzle 1 through the valve 17 and sprayed from its tip with an appropriate particle size, has a total air content of 10 to 10 of the total air supplied from the primary air inlet 3.
Although it is mixed with 30% of primary air and burned, the flame temperature is kept low because it burns in a state of insufficient oxygen concentration. At the same time, the secondary air supplied at a high speed (20 to 40 m / s) from the secondary air injection port 8 via the taper-shaped gap between the primary cone 5 and the secondary cone 7 has a hollow conical shape. Therefore, the combustion gas and the unburned gas after the primary combustion gradually burn while being entrained in the high-speed secondary air flow 9 to form a thin film flame flow 13 (see FIG. 2).

【００２１】図２は本発明の低ＮＯｘバ−ナをボイラで
使用した例を示す図である。低ＮＯｘバ−ナはボイラ１
１の水管壁１８で囲まれた燃焼室１２の上部に取り付け
られる。図２のように、大きなモ−メンタムを持った２
次空気流９及び薄膜火炎流１３は、実線で示すように燃
焼ガスや未燃ガスが巻き込まれ薄膜火炎流１３の内と外
に燃焼ガスの自己排ガス再循環流１４、１５を発生する
から、一般的な拡散燃焼に比べて局部的に高温度になる
ことはなく、火炎温度は低く抑えられＮＯｘの発生を低
減する。FIG. 2 is a diagram showing an example in which the low NOx burner of the present invention is used in a boiler. Low NOx burner is boiler 1
It is attached to the upper part of the combustion chamber 12 surrounded by the water tube wall 18 of No. 1. 2 with a large momentum, as shown in Figure 2.
Since the next air flow 9 and the thin film flame flow 13 are entrained with combustion gas and unburned gas as shown by the solid line, and self-exhaust gas recirculation flows 14 and 15 of the combustion gas are generated inside and outside the thin film flame flow 13. Compared with general diffusion combustion, the temperature does not locally become high, the flame temperature is kept low, and the generation of NOx is reduced.

【００２２】図３は本発明の低ＮＯｘバ−ナの２次空気
噴射口の詳細を示す図である。２次空気噴射口８は図３
（Ａ）のように全円周に開口部８ａが形成される場合
と、図３（Ｂ）のように開口部８ａと閉鎖部８ｂに形成
される場合がある。前者の場合は２次空気噴射口８から
噴射される２次空気流９は分割されない中空円錐状にな
るのに対して、後者の場合は分割された中空円錐状の２
次空気流９となる。これにより後者の場合は、２次空気
の濃淡により分割火炎が発生するので、更にＮＯｘの低
減効果が得られる。FIG. 3 is a view showing details of the secondary air injection port of the low NOx burner of the present invention. The secondary air injection port 8 is shown in FIG.
The opening 8a may be formed on the entire circumference as shown in FIG. 3A, or the opening 8a and the closed portion 8b may be formed as shown in FIG. 3B. In the former case, the secondary air flow 9 injected from the secondary air injection port 8 has an undivided hollow conical shape, whereas in the latter case, it has a divided hollow conical shape.
It becomes the next air flow 9. As a result, in the latter case, the divided flame is generated due to the density of the secondary air, so that the NOx reduction effect can be further obtained.

【００２３】上記構成の低ＮＯｘバ−ナ（油噴霧バ−
ナ）をボイラ１１に適用する場合には燃焼室１２の形状
に合わせて、２次空気流９の噴出角度θ１を決定するこ
とにより、火炎が纏まり煤の発生が少ない安定した燃焼
が可能となる。A low NOx burner (oil spray burner) of the above construction.
(A) is applied to the boiler 11, the ejection angle θ1 of the secondary air flow 9 is determined in accordance with the shape of the combustion chamber 12 to enable stable combustion with less flame generation and soot generation. .

【００２４】図４は本発明の低ＮＯｘバ−ナと従来のバ
−ナのＮＯｘ特性を示す図である。燃料油として灯油を
用い、本発明による低ＮＯｘバ−ナと従来のバ−ナによ
る貫流ボイラ１１でのＮＯｘの発生量を実測した結果を
示す。FIG. 4 is a diagram showing the NOx characteristics of the low NOx burner of the present invention and the conventional burner. The result of actually measuring the amount of NOx generated in the once-through boiler 11 by the low NOx burner according to the present invention and the conventional burner using kerosene as the fuel oil is shown.

【００２５】図４に示すように、従来の低ＮＯｘバ−ナ
に比べて、本発明の低ＮＯｘバ−ナはＮＯｘ発生が３０
〜４０％低減されることが分かる。本発明の低ＮＯｘバ
−ナは、圧力噴霧式の燃料噴霧ノズル１だけでなく２流
体噴霧式にも適用可能である。As shown in FIG. 4, compared with the conventional low NOx burner, the low NOx burner of the present invention produces 30 NOx.
It can be seen that the reduction is -40%. The low NOx burner of the present invention can be applied not only to the fuel atomizing nozzle 1 of the pressure atomizing type but also to the two fluid atomizing type.

【００２６】図５は本発明の低ＮＯｘバ−ナの燃料噴霧
ノズルの例を示す図である。圧力噴霧式の場合は、図５
のような噴霧パタ−ンのノズルチップを使用し、噴霧角
度θ２を２次空気の噴出角度θ１に等しくすれば燃焼室
１２内の自己排ガス再循環流１４、１５が活発になり、
更にＮＯｘの発生が低減される。FIG. 5 is a view showing an example of the fuel spray nozzle of the low NOx burner of the present invention. In the case of pressure spray type, Fig. 5
If a spray tip nozzle tip such as the one described above is used and the spray angle θ2 is made equal to the jet angle θ1 of the secondary air, the self-exhaust gas recirculation flows 14, 15 in the combustion chamber 12 become active,
Furthermore, the generation of NOx is reduced.

【００２７】なお、上記説明ではバ−ナを油バ−ナとし
て説明したが、本発明は油バ−ナに限定するものでな
く、ガスバ−ナへも適用可能であり同等又はそれ以上の
低減効果が得られる。Although the burner has been described as an oil burner in the above description, the present invention is not limited to an oil burner and can be applied to a gas burner, and the same or more reduction is possible. The effect is obtained.

【００２８】[0028]

【発明の効果】以上、詳細に説明したように本発明によ
れば、下記のような優れた効果が期待される。 （１）簡単な構造でＮＯｘ抑制の相乗効果が得られるの
で低減効果が大きい。 （２）１次空気と中空円錐状に高速で噴出する２次空気
により、薄膜（分割）火炎、自己再循環、２段燃焼によ
る低ＮＯｘ化の相乗効果があり、火炎もコンパクトにな
るので燃焼室負荷の高いボイラにも適用可能である。 （３）従来のバ−ナに比べて１次空気量が少なく点火装
置部での流速が遅く出来るため安定した着火が可能とな
る。As described in detail above, according to the present invention, the following excellent effects are expected. (1) Since the synergistic effect of suppressing NOx can be obtained with a simple structure, the reducing effect is large. (2) The primary air and the secondary air that ejects at a high speed in the shape of a hollow cone have the synergistic effect of thin film (split) flame, self-recirculation, and two-stage combustion to reduce NOx, and the flame becomes compact, so combustion It is also applicable to boilers with high room load. (3) Compared with the conventional burner, the amount of primary air is small and the flow velocity in the ignition device can be slowed down so that stable ignition is possible.

【図面の簡単な説明】[Brief description of drawings]

【図１】本発明の低ＮＯｘバ−ナの縦断面を示す図であ
る。FIG. 1 is a view showing a vertical cross section of a low NOx burner of the present invention.

【図２】本発明の低ＮＯｘバ−ナをボイラで使用した例
を示す図である。FIG. 2 is a diagram showing an example in which the low NOx burner of the present invention is used in a boiler.

【図３】本発明の低ＮＯｘバ−ナの２次空気噴射口詳細
図である。FIG. 3 is a detailed view of the secondary air injection port of the low NOx burner of the present invention.

【図４】本発明の低ＮＯｘバ−ナと従来の低ＮＯｘバ−
ナのＮＯｘ特性を示す図である。FIG. 4 is a low NOx burner of the present invention and a conventional low NOx burner.
It is a figure which shows the NOx characteristic of Na.

【図５】本発明の低ＮＯｘバ−ナの燃料噴霧ノズルの例
を示す図である。FIG. 5 is a view showing an example of the fuel spray nozzle of the low NOx burner of the present invention.

【図６】従来の低ＮＯｘバ−ナの縦断面を示す図であ
る。FIG. 6 is a view showing a vertical cross section of a conventional low NOx burner.

【符号の説明】[Explanation of symbols]

１ 燃料噴霧ノズル ２ １次空気筒 ３ １次空気導入口 ４ １次保炎板 ５ １次コ−ン ６ ２次空気筒 ７ ２次コ−ン ８ ２次空気噴射口 ８ａ 開口部 ８ｂ 閉塞部 ９ ２次空気流 １０ 風箱 １１ ボイラ １２ 燃焼室 １３ 薄膜火炎流 １４ 自己排ガス再循環流 １５ 自己排ガス再循環流 １６ 着火装置 １７ バルブ １８ 水管壁 1 Fuel Spray Nozzle 2 Primary Air Cylinder 3 Primary Air Inlet 4 Primary Flame Retaining Plate 5 Primary Cone 6 Secondary Air Cylinder 7 Secondary Cone 8 Secondary Air Injection Port 8a Opening 8b Closure 9 Secondary air flow 10 Wind box 11 Boiler 12 Combustion chamber 13 Thin film flame flow 14 Self-exhaust gas recirculation flow 15 Self-exhaust gas recirculation flow 16 Ignition device 17 Valve 18 Water pipe wall

Claims (2)

【特許請求の範囲】[Claims] 【請求項１】 中央部に燃料噴霧ノズルを配置し、その
外周より燃焼用空気を供給する構成の低ＮＯｘバ−ナに
おいて、 前記燃料噴霧ノズルの外側に１次空気筒を配設すると共
に、該燃料噴霧ノズルの先端近傍に位置し、且つ該１次
空気筒の先端に１次保炎板を取り付け、 前記１次空気筒の外側に２次空気筒を配設し、 前記１次保炎板に前方に円錐状に広がる１次コ−ンを設
けると共に、該１次コ−ンの外側で且つ前記２次空気筒
の先端から前方に円錐状に広がる２次コ−ンを設け、 前記燃焼用空気を前記１次空気筒の内側を通過させ前記
１次保炎板より噴出する１次空気と、前記２次空気筒と
１次空気筒の間を経由し前記１次コ−ンと２次コ−ンと
の隙間を通りその先端の２次空気噴出口より噴出する２
次空気とに分けて供給し、該２次空気を中空円錐状に噴
出することを特徴とする低ＮＯｘバ−ナ。1. A low NOx burner having a structure in which a fuel spray nozzle is arranged in the central portion and combustion air is supplied from the outer periphery of the fuel spray nozzle, and a primary air cylinder is arranged outside the fuel spray nozzle. A primary flame holding plate is attached to the tip of the fuel spray nozzle and is attached to the tip of the primary air cylinder, and a secondary air cylinder is arranged outside the primary air cylinder. The plate is provided with a primary cone that spreads forward in a conical shape, and a secondary cone that spreads in a cone shape forward from the tip of the secondary air cylinder is provided outside the primary cone. Combustion air passes through the inside of the primary air cylinder and is ejected from the primary flame holding plate, and the primary air passes between the secondary air cylinder and the primary air cylinder. It passes through the gap with the secondary cone and is ejected from the secondary air ejection port at the tip 2
A low NOx burner characterized in that the secondary air is separately supplied and is ejected in the shape of a hollow cone. 【請求項２】 前記１次コ−ンと前記２次コ−ンの隙間
の先端の前記２次空気噴出口は開口部と閉塞部に分割配
置した構成であることを特徴とする請求項１記載の低Ｎ
Ｏｘバ−ナ。2. The secondary air ejection port at the tip of the gap between the primary cone and the secondary cone is divided into an opening portion and a closed portion. Low N stated
Ox burner.