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JP4674001B2 - Once-through boiler - Google Patents

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JP4674001B2
JP4674001B2 JP2001150633A JP2001150633A JP4674001B2 JP 4674001 B2 JP4674001 B2 JP 4674001B2 JP 2001150633 A JP2001150633 A JP 2001150633A JP 2001150633 A JP2001150633 A JP 2001150633A JP 4674001 B2 JP4674001 B2 JP 4674001B2
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gas
gas supply
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JP2002340303A (en
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哲 南
啓宏 小倉
誠 平野
広一 市来
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Osaka Gas Co Ltd
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Description

【０００１】
【発明の属する技術分野】
本発明は、筒状の加熱室の内部に、加熱対象の水を通流させる複数の水管が夫々の長手方向を前記加熱室の軸心方向に沿わせる姿勢で、前記軸心方向に沿う軸心方向視にて環状に設けられ、
バーナが、前記加熱室における前記軸心方向一端側の中央部に配置されて、前記環状水管群の中央の空間を燃焼空間としてガス燃料を燃焼させるように構成された貫流ボイラに関する。
【０００２】
【従来の技術】
かかる貫流ボイラにおいては、バーナにより、ガス燃料を、火炎の温度が極力低くなるようにしながら安定燃焼させるようにして、窒素酸化物（ＮＯｘ）及び一酸化炭素（ＣＯ）の発生量を低減することが望まれる。
このような目的を達成するために、バーナにて形成される火炎を水管にて冷却するようにすることが行われている。つまり、火炎の温度を低くするほど窒素酸化物の発生量が少なくなるので、バーナにて形成される火炎を水管にて冷却することにより、火炎の温度を低くして窒素酸化物の発生量を少なくしようとするものである。一方、バーナにて形成される火炎を水管にて冷却するにしても、火炎を冷却し過ぎると燃焼が不安定になって、一酸化炭素の発生量が増加する。そこで、窒素酸化物の発生量を低減すべく、火炎を水管にて冷却するようにするにしても、安定燃焼を維持できるように火炎が冷却され過ぎないようにして、一酸化炭素の発生量を低減する必要がある。
【０００３】
かかる貫流ボイラにおいて、バーナにて形成される火炎を水管にて冷却するようにするに当たって、従来は、図１２に示すように、バーナＢを、周方向に分散させて火炎Ｆを形成するように構成して、そのバーナＢと水管群Ｐとを、対応する水管３３に対する各火炎Ｆの位置関係が全ての火炎Ｆで略同一となるように配設して、分散形成される各火炎Ｆを水管３３にて均等に冷却しようとするものがあった（例えば、特開平１１−３２５４０２号公報参照）。
かかる貫流ボイラにおいて用いられるバーナＢとしては、従来、一般に、図１３に示すように、先端が閉塞されたガス供給筒３７の先端側の周壁に、複数のガス噴出孔３８を周方向に分散させて穿設し、それら複数のガス噴出孔３８から噴出されるガス燃料Ｇに燃焼用空気Ａを吐出する空気流路３９を、ガス供給筒３７の外周部に、ガス供給筒３７の軸心方向視にて環状に設けて、周方向に隣接するガス噴出孔３８同士で、分割状に火炎Ｆを形成するように構成していた（例えば、特開平１１−３３７０２２号公報参照）。
そして、上述のように構成したバーナＢを、図１２に示すように、ガス供給筒３７の長手方向を筒状の加熱室３２の軸心方向に沿わせるように配置していた。尚、図１２中、３４は、バーナＢにてガス燃料を燃焼させるための燃焼空間である。
【０００４】
【発明が解決しようとする課題】
しかしながら、従来の貫流ボイラでは、ガス燃料は、ガス供給筒の先端側の周壁に穿設したガス噴出孔から噴出されることから、ガス噴出方向が不安定となって、延いては、火炎の形成方向が不安定となって、予め定めた条件通り（例えば、水管に対する火炎の接触面積や接触量）に火炎が水管に当たり難いので、火炎の冷却が不十分となって窒素酸化物の発生量が増加したり、あるいは、火炎の冷却が過度となって燃焼が不安定となり、一酸化炭素の発生量が増加したりするという問題があり、窒素酸化物の発生量の低減と一酸化炭素の発生量の低減を両立させる上で改善の余地があった。
つまり、ガス供給筒の周壁にガス噴出孔を穿設するに当たっては、所望のガス燃料噴出量が得られるようにガス噴出孔の内径を確保する必要があり、一方では、ガス供給筒の周壁を厚くするにしても限度があることから、ガス噴出孔の内径に対する軸心方向での長さの比率が小さい（通常、前記比率は１より小さい）ので、ガス噴出孔はガス燃料の通流を案内する作用が弱く、ガス噴出孔から噴出されるガス燃料の噴出方向が不安定となり、延いては、火炎の形成方向が不安定となるのである。
従って、窒素酸化物の発生量を低減すると共に、一酸化炭素の発生量を低減すべく、火炎が適度に冷却されるように、環状水管群と複数のガス噴出孔とを配設するものの、火炎の形成方向が不安定となるため、予め定めた条件通りに火炎が冷却され難く、火炎の冷却が不十分になったり、過度になったりするのである。
【０００５】
本発明は、かかる実情に鑑みてなされたものであり、その目的は、窒素酸化物の発生量の低減と一酸化炭素の発生量の低減を両立させ得る貫流ボイラを提供することにある。
【０００６】
【課題を解決するための手段】
〔請求項１記載の発明〕
請求項１に記載の特徴構成は、前記バーナが、長手方向を前記軸心方向に沿わせて配置されるガス供給筒と、そのガス供給筒の先端側の周壁にその周壁から突出する状態で周方向に分散して設けられて、前記ガス供給筒内を流れるガス燃料を噴出する複数の筒状ガスノズルと、前記軸心方向視にて前記ガス供給筒の外周部に環状に設けられて、前記複数の筒状ガスノズルから噴出されるガス燃料に対して燃焼用空気を吐出する空気流路とを備えて構成され、
前記環状水管群と前記複数の筒状ガスノズルとが、全ての前記筒状ガスノズルにて形成される火炎が同一又は略同一の条件で前記水管により冷却される相対位置関係にて配設され、
前記空気流路が、内側空気流路と、その内側空気流路の外周部に位置し且つ出口が前記内側空気流路の出口よりも前記軸心方向の後端側に位置する外側空気流路とから構成され、
前記複数の筒状ガスノズルが、前記外側空気流路の出口から吐出される燃焼用空気に対してガス燃料を噴出するように周方向に分散して並ぶ上流側ノズル列と、その上流側ノズル列よりも前記軸心方向の先端側に位置して、前記内側空気流路の出口から吐出される燃焼用空気又は前記外側空気流路の出口から吐出される燃焼用空気に対してガス燃料を噴出するように周方向に分散して並ぶ下流側ノズル列とを形成するように、前記ガス供給筒に設けられ、
前記上流側ノズル列の各前記筒状ガスノズルが、軸心が前記ガス供給筒の軸心に直交し且つ前記軸心方向視にて長手方向が前記ガス供給筒の径方向に沿う姿勢となるように設けられ、
前記下流側ノズル列の前記筒状ガスノズルとして、軸心が前記ガス供給筒の軸心に直交し且つ前記軸心方向視にて長手方向が前記ガス供給筒の径方向に沿う姿勢の筒状ガスノズルと、軸心が前記ガス供給筒の軸心に直交する方向に対して前方に傾斜し且つ前記軸心方向視にて長手方向が前記ガス供給筒の径方向に沿う姿勢の筒状ガスノズルとが、前記ガス供給筒の周方向に交互に並ぶように設けられていることにある。
請求項１に記載の特徴構成によれば、ガス供給筒の先端側の周壁にその周壁から突出する状態で周方向に分散して設けられた複数の筒状ガスノズル夫々から、噴出方向が安定した状態でガス燃料が噴出され、そのように噴出方向が安定する状態で複数の筒状ガスノズルから噴出されるガス燃料に対して、空気流路から燃焼用空気が吐出されるので、各筒状ガスノズルにて、火炎形成方向が安定した状態で火炎が形成される。
そして、そのように、各筒状ガスノズルにて火炎形成方向が安定した状態で火炎が形成されるようにしてあるので、環状水管群と複数の筒状ガスノズルとを、全ての筒状ガスノズルにて形成される火炎が同一又は略同一の条件で水管により冷却される相対位置関係にて配設すると、予め、窒素酸化物の発生量を低減すると共に一酸化炭素の発生量を低減すべく、火炎が適度に冷却されるように定めた条件（例えば、水管に対する火炎の接触面積や接触量）と同一又は略同一の条件にて、全ての筒状ガスノズルにて形成される火炎を水管にて安定して冷却することができる。
つまり、筒状ガスノズルは、内径に対して軸心方向での長さを長くすることができる（内径に対する軸心方向での長さの比率を１以上に適宜設定可能）ことから、筒状ガスノズルはガス燃料の通流を案内する作用を強く、筒状ガスノズルからは、燃料ガスが効果的に直進性を与えられて拡散が抑制される状態で噴出されるので、筒状ガスノズルからのガス噴出方向が安定するのである。
そして、各筒状ガスノズルにて火炎形成方向が安定した状態で火炎が形成されるので、窒素酸化物の発生量を低減すると共に一酸化炭素の発生量を低減すべく、全ての筒状ガスノズルにて形成される火炎を同一又は略同一に適度に冷却されるように、予め定めた相対位置関係にて、環状水管群と複数の筒状ガスノズルとを配設すると、全ての筒状ガスノズルにて形成される火炎を予め定めた条件通りに安定して冷却することができるのである。
しかも、燃料ガスが、筒状ガスノズルにより効果的に直進性を与えられて拡散が抑制された状態で噴出されることから、筒状ガスノズルの周囲に負圧域（周囲よりも圧力が低い領域）が形成されるので、その負圧域による誘引作用により、筒状ガスノズルから噴出された燃料ガスが燃焼した燃焼ガスを循環させて、筒状ガスノズルから噴出された燃料ガスの燃焼域に燃焼ガスを流入させながら、燃料ガスを燃焼させる、所謂、排ガス再循環により、燃料ガスを効果的に緩慢燃焼させて、火炎の温度を一層低下させることができる。
従って、窒素酸化物の発生量の低減と一酸化炭素の発生量の低減を両立させ得る貫流ボイラを提供することができるようになった。
また、請求項１に記載の特徴構成によれば、上流側ノズル列における前記周方向に並ぶ複数の筒状ノズルから噴出されたガス燃料は、外側空気流路の出口から吐出される燃焼用空気にて燃焼し、その上流側ノズル列よりも前記軸心方向の先端側に位置する下流側ノズル列における前記周方向に並ぶ複数の筒状ガスノズルから噴出されたガス燃料は、内側空気流路の出口から吐出される燃焼用空気又は外側空気流路の出口から吐出される燃焼用空気にて燃焼する。
つまり、上流側ノズル列における前記周方向に並ぶ複数の筒状ノズルから噴出されたガス燃料を、外側空気流路の出口から吐出される燃焼用空気にて燃焼させて一次燃焼を行わせ、その一次燃焼にて形成される火炎に対して、下流側ノズル列における前記周方向に並ぶ複数の筒状ガスノズルからガス燃料を供給して、そのガス燃料を、内側空気流路の出口から吐出される燃焼用空気又は外側空気流路の出口から吐出される燃焼用空気にて燃焼させて、複数段燃焼を行わせることにより、火炎中に局所的に高温領域が発生するのを防止して、窒素酸化物の発生を抑制するのである。
従って、複数段燃焼によりＮＯｘの発生を抑制することができるので、窒素酸化物の発生量を一段と低減することができるようになった。
【０００７】
〔請求項２記載の発明〕
請求項２に記載の特徴構成は、前記複数の筒状ガスノズルが、周方向に隣接するもの同士で分割状に火炎を形成するように、周方向に分散して設けられていることにある。
請求項２に記載の特徴構成によれば、各火炎の火炎形成方向が安定した状態で、複数の火炎が周方向に分散されて形成されて、各火炎が独立して水管にて冷却される。
つまり、環状水管群と複数の筒状ガスノズルとを、全ての筒状ガスノズルにて形成される火炎が同一又は略同一の条件で水管により冷却される相対位置関係にて配設するに当たって、複数の火炎が周方向に分散して形成されるようにして、各火炎が独立して水管にて冷却されるようにすることにより、火炎が周方向に連なる状態で形成される場合に比べて、周方向に隣接する火炎の干渉を抑制することができて、各火炎を予め定めた条件通りに水管に当てることができるので、全ての筒状ガスノズルにて形成される火炎を予め定めた条件で水管により冷却することを、良好に行えるのである。
しかも、複数の火炎が周方向に分散して形成されるようにすることにより、火炎が周方向に連なる状態で形成される場合に比べて、各筒状ガスノズルの燃焼域に対する燃焼ガスの流入を促進させることができて、排ガス再循環を一層効果的に行わせることができるので、火炎の温度を一層低下させることができる。
従って、窒素酸化物の発生量並びに一酸化炭素の発生量を一段と低減することができるようになった。
【０００８】
〔請求項３記載の発明〕
請求項３に記載の特徴構成は、前記環状水管群における最内周側に、前記複数の筒状ガスノズルと同数の前記水管が環状に並ぶ最内周環状水管列が形成され、
前記筒状ガスノズルが、前記軸心方向視にて、その長手方向を前記ガス供給筒の径方向に沿わせ、且つ、その先端を前記最内周環状水管列の前記水管に対して前記周方向にずらした状態で前記ガス供給筒に設けられ、
前記軸心方向視にて、前記筒状ガスノズルから噴出されるガス燃料の燃焼により形成される火炎が、前記径方向に対して前記周方向側に傾く状態となるように、前記筒状ガスノズルから噴出されるガス燃料に対して、前記空気流路の出口から燃焼用空気を吐出させる空気吐出手段が設けられていることにある。
つまり、かかる貫流ボイラにおいては、熱負荷に応じてバーナの燃焼量を変更させるが、その燃焼量の変更に伴って、筒状ガスノズルから噴出されるガス燃料の燃焼により形成される火炎の長さが変化するので、火炎の長さが変化しても、火炎を、窒素酸化物の発生量を低減すると共に一酸化炭素の発生量を低減すべく、適度に冷却する必要があり、一方では、ガス供給筒の径方向に沿う方向において筒状ガスノズルの先端と最内周環状水管列の水管との間隔を狭くして、貫流ボイラを小型化することが望まれる。
そこで、筒状ガスノズルを、前記軸心方向視にて、その長手方向をガス供給筒の径方向に沿わせ、且つ、その先端を最内周環状水管列の水管に対して前記周方向にずらした状態でガス供給筒に設け、前記軸心方向視にて、筒状ガスノズルから噴出されるガス燃料の燃焼により形成される火炎が、前記径方向に対して前記周方向側に傾く状態となるように、筒状ガスノズルから噴出されるガス燃料に対して、空気流路の出口から燃焼用空気を吐出させる空気吐出手段を設けることにより、前記径方向に沿う方向において筒状ガスノズルの先端と最内周環状水管列の水管との間隔を狭くしながらも、燃焼量が小さくて火炎が短いときは、火炎が水管に当たり難いようにして、水管による火炎の冷却を抑制し、一方、燃焼量が大きくなって火炎が長くなるほど、火炎が水管に当たり易いようにして、火炎が水管により冷却され易くなるようにすることができ、燃焼量の変更に伴って火炎の長さが変化しても、火炎を、窒素酸化物の発生量を低減すると共に一酸化炭素の発生量を低減すべく、適度に冷却することができる。
ちなみに、筒状ガスノズルを、前記軸心方向視にて、その長手方向をガス供給筒の径方向に沿わせ、且つ、その先端が最内周環状水管列の水管に対向するようにガス供給筒に設け、前記軸心方向視にて、筒状ガスノズルから噴出されるガス燃料の燃焼により形成される火炎が、前記径方向に沿う方向に形成されるようにする場合が想定されるが、その場合は、前記径方向に沿う方向において筒状ガスノズルの先端と最内周環状水管列の水管との間隔を狭くすると、燃焼量が小さくて火炎が短いときも、火炎が水管に当たり易いため、冷却され過ぎて、燃焼が不安定となる虞があるので、前記間隔を短くする上で不利となる。
従って、窒素酸化物の発生量の低減と一酸化炭素の発生量の低減を両立させながらも、貫流ボイラを小型化することができるようになった。
【０００９】
〔請求項４記載の発明〕
請求項４に記載の特徴構成は、前記外側空気流路の出口側に、前記空気吐出手段としての空気吐出部が、前記軸心方向視にて、周方向において、隣接する前記筒状ガスノズルの間に燃焼用空気を吐出するように設けられていることにある。
請求項４に記載の特徴構成によれば、前記軸心方向視にて、筒状ガスノズルから噴出されたガス燃料噴出流の両側を、燃焼用空気が流れるので、筒状ガスノズルから噴出されたガス燃料は、前記軸心方向視にて、その両側から燃焼用空気が供給されて、二股状になるが如き形状の火炎が形成される状態で燃焼する。そして、二股状になるが如き形状の火炎の両側の火炎は、夫々、前記軸心方向視にて、前記径方向に対して前記周方向側に傾く状態となるように形成される。
しかも、筒状ガスノズルから噴出されたガス燃料を、二股状になるが如き形状の火炎が形成される状態で燃焼させることにより、火炎の表面積を増加させて、火炎の冷却作用を増大させることにより、窒素酸化物の発生を一層抑制することができる。
従って、窒素酸化物の発生量の低減と一酸化炭素の発生量の低減を両立させながらも貫流ボイラを小型化するようにするに当たって、一段と窒素酸化物の発生量を低減できるようにする上で好ましい具体構成を提供することができる。
【００１０】
〔請求項５記載の発明〕
請求項５に記載の特徴構成は、前記空気流路の出口側に、前記空気吐出手段としての旋回手段が、前記空気流路を流れる燃焼用空気を旋回させて出口から吐出させるように設けられていることにある。
請求項５に記載の特徴構成によれば、旋回手段によって、燃焼用空気が空気流路の出口から旋回させられる状態で吐出されて、筒状ガスノズルから噴出されたガス燃料に対して供給されるので、その旋回力により、筒状ガスノズルから噴出されたガス燃料の燃焼により形成される火炎は、前記軸心方向視にて、前記径方向に対して前記周方向側に傾く状態となるように形成される。
しかも、燃焼用空気が空気流路の出口から旋回させられる状態で吐出されることから、ガス燃料と燃焼用空気との混合状態が促進されて、燃焼の安定性が向上するので、一酸化炭素の発生を一層抑制することができる。
従って、窒素酸化物の発生量の低減と一酸化炭素の発生量の低減を両立させながらも貫流ボイラを小型化するようにするに当たって、一段と一酸化炭素の発生量を低減できるようにする上で好ましい具体構成を提供することができる。
【００１２】
【発明の実施の形態】
〔第１実施形態〕
以下、本発明の第１実施形態を説明する。
図１及び図２に示すように、円筒状の缶体３１をその軸心方向を上下方向に向けて設けて、缶体３１の内部に、軸心方向が上下方向を向く円筒状の加熱室３２を形成し、その円筒状の加熱室３２の内部に、加熱対象の水を通流させる複数の水管３３を夫々の長手方向を加熱室３２の軸心方向に沿わせる姿勢で、前記軸心方向に沿う軸心方向視にて環状に設け、バーナＢを、加熱室３２における前記軸心方向一端側（上端側）の中央部に配置して、前記環状水管群Ｐの中央の空間を燃焼空間３４としてガス燃料Ｇを燃焼させるように構成してある。
【００１３】
そして、本発明においては、図３及び図４にも示すように、バーナＢを、長手方向を前記軸心方向に沿わせて配置されるガス供給筒１と、そのガス供給筒１の先端側の周壁にその周壁から突出する状態で周方向に分散して設けられて、ガス供給筒１内を流れるガス燃料Ｇを噴出する複数の筒状ガスノズル２と、前記軸心方向視にてガス供給筒１の外周部に環状に設けられて、複数の筒状ガスノズル２から噴出されるガス燃料Ｇに対して燃焼用空気Ａを吐出する空気流路３とを備えて構成し、環状水管群Ｐと複数の筒状ガスノズル２とを、全ての筒状ガスノズル２にて形成される火炎Ｆが同一又は略同一の条件で水管３３により冷却される相対位置関係にて配設してある。
【００１４】
説明を加えると、環状水管群Ｐは、内周側に、バーナＢの複数の筒状ガスノズル２と同数の水管３３が環状に並ぶ最内周環状水管列Ｐｉが形成され、外周側に、複数の水管３３が環状に並ぶ最外周環状水管列Ｐｏが形成されるように、前記軸心方向視にて２列状に形成してある。
最内周環状水管列Ｐｉは、複数の水管３３を周方向に均等に分散する状態で配置すると共に、隣接する水管３３同士を、下方側を開放する状態でひれ状部材３８にて接続して形成し、最外周環状水管列Ｐｏは、複数の水管３３を周方向に均等に分散する状態で配置すると共に、隣接する水管３３同士を上方側を開放する状態でひれ状部材３８にて接続して形成してある。
そして、バーナＢの燃焼ガスＥを、最内周環状水管列Ｐｉの下部側から、最内周環状水管列Ｐｉと最外周環状水管列Ｐｏとの間に流入させて、その間を通流させた後、最外周環状水管列Ｐｏの上部側から流出させて、排気路３５を通じて排出させるように、燃焼ガスＥの通流路を形成してある。
【００１５】
缶体３１の上端には、周方向に連なるリング状の蒸気ドラム３６を設け、下端には、周方向に連なるリング状の水ドラム３７を設けて、環状水管群Ｐの各水管３３の上端を蒸気ドラムに連通接続し、環状水管群Ｐの各水管３３の下端を水ドラム３７に連通接続して、加熱対象の水をポンプ（図示省略）にて水ドラム３７に供給して、各水管３３を上方に向けて蒸気ドラム３６へ通流させて、バーナＢにより加熱することにより、蒸気を生成して、生成蒸気を蒸気需要先に供給するように構成してある。
【００１６】
次に、図２ないし図４に基づいて、バーナＢについて説明を加える。
第１実施形態においては、筒状ガスノズル２を、前記軸心方向視にて、その長手方向をガス供給筒１の径方向に沿わせ、且つ、その先端を最内周環状水管列Ｐｉの水管３３に対してガス供給筒１の周方向にずらした状態でガス供給筒１に設け、前記軸心方向視にて、筒状ガスノズル２から噴出されるガス燃料Ｇの燃焼により形成される火炎Ｆが、ガス供給筒１の径方向に対して筒状ガスノズル２の周方向側に傾く状態となるように、筒状ガスノズル２から噴出されるガス燃料Ｇに対して、空気流路３の出口から燃焼用空気Ａを吐出させる空気吐出手段Ｔを設けてある。
【００１７】
又、空気流路３を、内側空気流路３ｉと、その内側空気流路３ｉの外周部に位置し且つ出口が内側空気流路３ｉの出口よりも前記軸心方向の後端側に位置する外側空気流路３ｏとから構成し、複数の筒状ガスノズル２を、外側空気流路３ｏの出口から吐出される燃焼用空気Ａに対してガス燃料Ｇを噴出するように周方向に分散して並ぶ上流側ノズル列Ｎｕと、その上流側ノズル列Ｎｕよりも前記軸心方向の先端側に位置して、内側空気流路３ｉの出口から吐出される燃焼用空気Ａ及び外側空気流路３ｏの出口から吐出される燃焼用空気Ａに対してガス燃料Ｇを噴出するように周方向に分散して並ぶ下流側ノズル列Ｎｄとを形成するように、ガス供給筒１に設けてある。
【００１８】
説明を加えると、先端が閉塞された円筒状のガス供給筒１の外側に、円筒状の内側燃焼筒４をその先端がガス供給筒１の先端よりも後退する状態で同軸心状に設け、更に、その内側燃焼筒４の外側に、円筒状の外側燃焼筒５をその先端が内側燃焼筒４の先端よりも後退する状態で同軸心状に設けてある。そして、ガス供給筒１と内側燃焼筒４との間に、前記軸心方向視にて環状の内側空気流路３ｉを形成し、内側燃焼筒４と外側燃焼筒５との間に、前記軸心方向視にて環状の外側空気流路３ｏを形成してある。
内側燃焼筒４及び外側燃焼筒５夫々の両端は開口すると共に、内側燃焼筒４の後端を外側燃焼筒５の後端よりも前方に位置させて、内側燃焼筒４内、即ち、内側空気流路３ｉを外側燃焼筒５内に連通させてある。
【００１９】
ガス供給筒１の後端は外側燃焼筒５の後端よりも突出させ、風箱６を、ガス供給筒１の後端側を風箱６外に突出させ、且つ、外側燃焼筒５の後端開口を覆う状態で設けて、風箱６内に、外側空気流路３ｏ及び内側空気流路３ｉ夫々に連通する空気室７を形成してある。
【００２０】
ブロア８から燃焼用空気Ａが導入される空気供給路９を、空気室７に連通するように風箱６に接続して、燃焼用空気Ａを空気供給路９を通じて空気室７に供給して、その空気室７を介して、外側空気流路３ｏ及び内側空気流路３ｉ夫々に供給するように構成し、並びに、ガス供給筒１の後端には、都市ガス等のガス燃料Ｇが導入されるガス燃料供給路１０を接続してある。
【００２１】
ガス供給筒１において外側燃焼筒５の先端よりも先端側で且つ内側燃焼筒４にて覆われる部分の周壁に、長さが同一の複数の筒状ガスノズル２を、それぞれが内側燃焼筒４を貫通して内側燃焼筒４から突出する状態で、筒周方向に均等に分散して１列状に並ぶ状態で設けて、上流側ノズル列Ｎｕを形成してある。又、ガス供給筒１において内側燃焼筒４の先端より先端側の部分の周壁に、上流側ノズル列Ｎｕと同数の筒状ガスノズル２を、周方向において、上流側ノズル列Ｎｕにおける筒状ガスノズル２の並び位相と同位相で１列状に並ぶ状態で設けて、下流側ノズル列Ｎｄを形成してある。
【００２２】
上流側ノズル列Ｎｕの各筒状ガスノズル２は、軸心がガス供給筒１の軸心に直交し且つ前記軸心方向視にて長手方向がガス供給筒１の径方向に沿う姿勢となるように設け、上流側ノズル列Ｎｕの各筒状ガスノズル２により、ガス燃料Ｇを、ガス供給筒１の軸心に直交し且つ前記軸心方向視にてガス供給筒１の径方向に沿う方向に噴出するようにしてある。又、上流側ノズル列Ｎｕの各筒状ガスノズル２の先端は、前記軸心方向視にて、外側燃焼筒５と内側燃焼筒４との間に位置するようにして、上流側ノズル列Ｎｕの各筒状ガスノズル２により、ガス燃料Ｇを、外側空気流路３ｏの出口から吐出される燃焼用空気Ａに対して吐出するようにしてある。
【００２３】
又、下流側ノズル列Ｎｄにおいては、軸心がガス供給筒１の軸心に直交し且つ前記軸心方向視にて長手方向がガス供給筒１の径方向に沿う姿勢の筒状ガスノズル２と、軸心がガス供給筒１の軸心に直交する方向に対して前方に傾斜し且つ前記軸心方向視にて長手方向がガス供給筒１の径方向に沿う姿勢の筒状ガスノズル２とが、周方向に交互に並ぶように設けてある。つまり、下流側ノズル列Ｎｄは、ガス供給筒１の軸心に直交し且つ前記軸心方向視にてガス供給筒１の径方向に沿う方向にガス燃料Ｇを噴出する筒状ガスノズル２と、ガス供給筒１の軸心に直交する方向に対して前方に傾斜し且つ前記軸心方向視にてガス供給筒１の径方向に沿う方向にガス燃料Ｇを噴出する筒状ガスノズル２とが、周方向に交互に並ぶように形成してある。
又、下流側ノズル列Ｎｄの各筒状ガスノズル２の先端は、前記軸心方向視にて、外側燃焼筒５と内側燃焼筒４との間に位置するようにして、下流側ノズル列Ｎｄの各筒状ガスノズル２により、ガス燃料Ｇを、内側空気流路３ｉの出口から吐出される燃焼用空気Ａ及び外側空気流路３ｏの出口から吐出される燃焼用空気Ａに対して吐出するようにしてある。
【００２４】
内側空気流路３ｉの出口側には、空気吐出手段Ｔとしての内側旋回羽根１１（旋回手段に相当する）を、内側空気流路３ｉを流れる燃焼用空気Ａを旋回させて出口から吐出させるように設け、同様に、外側空気流路３ｏの出口側にも、空気吐出手段Ｔとしての外側旋回羽根１２（旋回手段に相当する）を、外側空気流路３ｏを流れる燃焼用空気Ａを旋回させて出口から吐出させるように設けてある。
【００２５】
尚、環状水管群Ｐを構成する水管３３の本数は、貫流ボイラの能力に応じて設定される伝熱面積に基づいて設定するが、第１実施形態では、例えば、最内周環状水管列Ｐｉを構成する水管３３の本数を１３本とし、最外周環状水管列Ｐｏを構成する水管３３の本数を１７本として、環状水管群Ｐを構成する水管３３の本数を、３０本としてある。
上流側ノズル列Ｎｕ及び下流側ノズル列Ｎｄ夫々を構成する筒状ガスノズル２の本数は、最内周環状水管列Ｐｉを構成する水管３３と同数の１３本としてある。
【００２６】
そして、上述のように構成したガスバーナＢを、加熱室３２における上端側の中央部に、ガス供給筒１の先端を燃焼空間３４に臨ませた状態で、且つ、前記軸心方向視にて、各筒状ガスノズル２の先端が、最内周環状水管列Ｐｉの隣接する水管３３同士の略中央における加熱室３２の中心側の位置に位置する状態で配設してある。
【００２７】
つまり、複数の水管３３を周方向に均等に分散した最内周環状水管列Ｐｉと、その最内周環状水管列Ｐｉの水管３３と同数の複数の筒状ガスノズル２を周方向に均等に分散した上流側ノズル列Ｎｕ及び下流側ノズル列Ｎｄ夫々とを、前記軸心方向視にて、各筒状ガスノズル２の先端が最内周環状水管列Ｐｉにおける隣接する水管３３同士の略中央に位置する相対位置関係にて配設することにより、対応する水管３３に対する各火炎Ｆの位置関係が全ての火炎Ｆで略同一となるようにして、全ての筒状ガスノズル２にて形成される火炎Ｆが同一の条件で水管３３により冷却されるように構成してある。
【００２８】
上述のように構成したバーナＢにおいては、以下に説明するように、ガス燃料Ｇを燃焼させる。
尚、上流側ノズル列Ｎｕから噴出されるガス燃料Ｇを外側空気流路３ｏの出口から吐出された燃焼用空気Ａにて燃焼させて、一次燃焼を行わせ、並びに、下流側ノズル列Ｎｄから噴出されるガス燃料Ｇを、外側空気流路３ｏの出口から吐出された燃焼用空気Ａのうち一次燃焼で余った燃焼用空気Ａと、内側空気流路３ｉの出口から吐出された燃焼用空気Ａにて燃焼させて、二次燃焼を行わせるように構成してある。
そして、上流側ノズル列Ｎｕから噴出されるガス燃料Ｇの量と下流側ノズル列Ｎｄから噴出されるガス燃料Ｇの量との比率は略１：１とし、外側空気流路３ｏの流路横断面積を内側空気流路３ｉの流路横断面積よりも大きくすることにより、一次燃焼では、空気過剰率を２．０程度に設定して希薄燃焼させるようにしてあり、一次燃焼と二次燃焼を合わせた全体の燃焼としては、空気過剰率は１．２程度に設定してある。
【００２９】
上流側ノズル列Ｎｕの１３本の筒状ガスノズル２から分割状態で噴出されるガス燃料Ｇに対して、外側空気流路３ｏの出口から燃焼用空気Ａが旋回する状態で吐出されるので、上流側ノズル列Ｎｕの１３本の筒状ガスノズル２により、各火炎Ｆが、前記軸心方向視にてガス供給筒１の径方向に対してガス供給筒１の周方向側に傾く状態で、火炎Ｆが１３分割状に形成される。
【００３０】
同様に、下流側ノズル列Ｎｄの１３本の筒状ガスノズル２から分割状態で噴出されるガス燃料Ｇに対して、内側空気流路３ｉ及び外側空気流路３ｏ夫々の出口から燃焼用空気Ａが旋回する状態で吐出されるので、下流側ノズル列Ｎｄの１３本の筒状ガスノズル２により、各火炎Ｆが、前記軸心方向視にてガス供給筒１の径方向に対してガス供給筒１の周方向側に傾く状態で、火炎Ｆが１３分割状に形成される。
尚、下流側ノズル列Ｎｄにおいては、ガス燃料Ｇの噴出方向が異なるガスノズル２を周方向に交互に並べてあるので、周方向に隣接するガスノズル２に形成される火炎Ｆ同士が一層離れて形成されるので、火炎Ｆの分離状態が一層明瞭になる。
【００３１】
そして、上流側ノズル列Ｎｕ及び下流側ノズル列Ｎｄ夫々においては、各筒状ガスノズル２から噴出方向が安定する状態でガス燃料Ｇが噴出されることから、各筒状ガスノズル２にて、火炎形成方向が安定した状態で火炎Ｆが形成されるので、全ての筒状ガスノズル２にて形成される火炎Ｆを、最内周環状水管列Ｐｉの水管３３によって、窒素酸化物の発生量を低減すると共に一酸化炭素の発生量を低減すべく定めた条件通りに、安定して冷却することができる。従って、窒素酸化物の発生量の低減と一酸化炭素の発生量の低減を両立させることができる。
【００３２】
しかも、上流側ノズル列Ｎｕ及び下流側ノズル列Ｎｄ夫々においては、各筒状ガスノズル２により、火炎Ｆは、前記軸心方向視にて、最内周環状水管列Ｐｉの隣接する水管３３同士の略中央における加熱室３２の中心側の位置から、ガス供給筒１の径方向に対してガス供給筒１の周方向側に傾くように形成されるので、燃焼量が小さくて火炎Ｆが短いときは、火炎Ｆが最内周環状水管列Ｐｉの水管３３に当たり難く、水管による火炎の冷却が抑制され、一方、燃焼量が大きくなって火炎Ｆが長くなるほど、火炎Ｆが最内周環状水管列Ｐｉの水管３３に当たり易くなり、火炎Ｆが水管３３により冷却され易くなる。従って、燃焼量の変更に伴って火炎Ｆの長さが変化しても、火炎Ｆを、窒素酸化物の発生量を低減すると共に一酸化炭素の発生量を低減すべく、適度に冷却することができる。
【００３３】
筒周方向に間隔を隔てて並ぶ下流側ノズル列Ｎｄの１３本の筒状ガスノズル２から、ガス燃料Ｇを直進性を効果的に与えた状態で噴出することにより、ガス供給筒１の前方空間から各筒状ガスノズル２の周部空間にわたって負圧域が形成されるので、図３に示すように、そのように負圧域となるガス供給筒１の前方空間、及び、各筒状ガスノズル２の周部空間を通して、下流側ノズル列Ｎｄの筒状ガスノズル２から噴出されたガス燃料Ｇが燃焼した燃焼ガスＥを効率良く循環させて、下流側ノズル列Ｎｄの筒状ガスノズル２から噴出されたガス燃料Ｇの燃焼域に燃焼ガスＥを効率良く流入させながら、ガス燃料Ｇを燃焼させることにより、ガス燃料Ｇを効果的に緩慢燃焼させることができ、窒素酸化物の発生を一層抑制することができる。
【００３４】
又、上流側ノズル列Ｎｕにおけるガス供給筒１の周方向に並ぶ複数の筒状ノズル２から噴出されたガス燃料Ｇを、外側空気流路３ｏの出口から吐出される燃焼用空気Ａにて燃焼させて一次燃焼を行わせ、その一次燃焼にて形成される火炎Ｆに対して、下流側ノズル列Ｎｄにおけるガス供給筒１の周方向に並ぶ複数の筒状ガスノズル２からガス燃料Ｇを供給して、そのガス燃料を、内側空気流路３ｉ及び外側空気流路３ｏ夫々の出口から吐出される燃焼用空気Ａにて燃焼させて、２段燃焼を行わせることにより、火炎中に局所的に高温領域が発生するのを防止して、窒素酸化物の発生を一層抑制することができる。
【００３６】
〔第２実施形態〕
以下、第２実施形態を説明する。
第２実施形態においては、環状水管群Ｐと複数の筒状ガスノズル２との配置形態が第１実施形態と異なる以外は、第１実施形態と同様に構成してあるので、以下では、主として、第１実施形態と異なる構成について説明する。
即ち、図５に示すように、第２実施形態においては、環状水管群Ｐは、第１実施形態と同様に、最内周環状水管列Ｐｉと最外周環状水管列Ｐｏとの２列状に形成してあるが、上流側ノズル列Ｎｕ及び下流側ノズル列Ｎｄ夫々において、筒状ガスノズル２を、前記軸心方向視にて、その長手方向をガス供給筒１の径方向に沿わせ、且つ、その先端を最内周環状水管列Ｐｉの水管３３に対向させた状態でガス供給筒１に設けてある。
【００３７】
従って、上流側ノズル列Ｎｕ及び下流側ノズル列Ｎｄ夫々において、各火炎Ｆが、前記軸心方向視にてガス供給筒１の径方向に対してガス供給筒１の周方向側に傾く状態で、火炎Ｆが１３分割状に形成される。
そして、各火炎Ｆは、火炎形成方向が安定した状態で形成される状態で、前記軸心方向視にて、最内周環状水管列Ｐｉの水管３３に対して真正面に対向する位置から、ガス供給筒１の径方向に対してガス供給筒１の周方向側に傾くように形成されることから、火炎Ｆは水管３３の側部に当たって、過度に冷却されることなく適度に冷却されることになり、全ての筒状ガスノズル２にて形成される火炎Ｆを、最内周環状水管列Ｐｉの水管３３によって、窒素酸化物の発生量を低減すると共に一酸化炭素の発生量を低減すべく定めた条件通りに、安定して冷却することができる。従って、窒素酸化物の発生量の低減と一酸化炭素の発生量の低減を両立させることができる。
【００３９】
〔第３実施形態〕
以下、第３実施形態を説明する。
第３実施形態においては、環状水管群Ｐにおける水管３３の配置形態、並びに、バーナＢにおける筒状ガスノズル２の設置本数及び空気吐出手段Ｔが第１実施形態と異なる以外は、第１実施形態と同様に構成してあるので、以下では、主として、第１実施形態と異なる構成について説明する。
【００４０】
即ち、図６及び図７に示すように、環状水管群Ｐは、最内周側に、バーナＢの複数の筒状ガスノズル２と同数の水管３３が環状に並ぶ最内周環状水管列Ｐｉが形成され、最外周側に、複数の水管３３が環状に並ぶ最外周環状水管列Ｐｏが形成され、並びに、最内周環状水管列Ｐｉと最外周環状水管列Ｐｏとの間に、複数の水管３３が環状に並ぶ中間環状水管列Ｐｍが形成されるように、前記軸心方向視にて３列状に形成してある。
【００４１】
最外周環状水管列Ｐｏは、複数の水管３３を周方向に均等に分散する状態で配置すると共に、隣接する水管３３同士を、下方側を開放する状態でひれ状部材３８にて接続して形成し、中間環状水管列Ｐｍも、最外周環状水管列Ｐｏと同数の水管３３を周方向に均等に分散する状態で配置すると共に、隣接する水管３３同士を、下方側を開放する状態でひれ状部材３８にて接続して形成してある。
最内周環状水管列Ｐｉは、複数の水管３３を、各水管３３が、中間環状水管列Ｐｍにおける隣接する水管３３同士の中間部のうち１個おきの中間部に位置する状態で、周方向に均等に分散させて配置して形成してある。最内周環状水管列Ｐｉにおいては、隣接する水管３３同士はひれ状部材３８にて接続せず、隣接する水管３３同士の間を開放させてある。
そして、バーナＢの燃焼ガスＥを、最内周環状水管列Ｐｉにおける水管３３同士の間を通し、中間環状水管列Ｐｍの下部側から、中間環状水管列Ｐｍと最外周環状水管列Ｐｏとの間に流入させて、その間を通流させた後、最外周環状水管列Ｐｏの上部側から流出させて、排気路３５を通じて排出させるように、燃焼ガスＥの通流路を形成してある。
【００４２】
図７ないし図１０に基づいて、バーナＢについて説明を加える。
複数の筒状ガスノズル２は、第１実施形態と同様に、上流側ノズル列Ｎｕ及び下流側ノズル列Ｎｄを形成するように、ガス供給筒１に設けてあるが、上流側ノズル列Ｎｕ及び下流側ノズル列Ｎｄ夫々における筒状ガスノズル２の設置本数が、第１実施形態と異なる８本としてある。
【００４３】
上流側ノズル列Ｎｕの各筒状ガスノズル２は、第１実施形態と同様に、軸心がガス供給筒１の軸心に直交し且つ前記軸心方向視にて長手方向がガス供給筒１の径方向に沿う姿勢となるように設け、上流側ノズル列Ｎｕの各筒状ガスノズル２により、ガス燃料Ｇを、ガス供給筒１の軸心に直交し且つ前記軸心方向視にてガス供給筒１の径方向に沿う方向に噴出するようにしてある。又、上流側ノズル列Ｎｕの各筒状ガスノズル２の先端は、第１実施形態と同様に、前記軸心方向視にて、外側燃焼筒５と内側燃焼筒４との間に位置するようにして、上流側ノズル列Ｎｕの各筒状ガスノズル２により、ガス燃料Ｇを、外側空気流路３ｏの出口から吐出される燃焼用空気Ａに対して吐出するようにしてある。
【００４４】
又、第１実施形態と同様に、下流側ノズル列Ｎｄにおいては、軸心がガス供給筒１の軸心に直交し且つ前記軸心方向視にて長手方向がガス供給筒１の径方向に沿う姿勢の筒状ガスノズル２と、軸心がガス供給筒１の軸心に直交する方向に対して前方に傾斜し且つ前記軸心方向視にて長手方向がガス供給筒１の径方向に沿う姿勢の筒状ガスノズル２とが、周方向に交互に並ぶように設けてある。つまり、下流側ノズル列Ｎｄは、ガス供給筒１の軸心に直交し且つ前記軸心方向視にてガス供給筒１の径方向に沿う方向にガス燃料Ｇを噴出する筒状ガスノズル２と、ガス供給筒１の軸心に直交する方向に対して前方に傾斜し且つ前記軸心方向視にてガス供給筒１の径方向に沿う方向にガス燃料Ｇを噴出する筒状ガスノズル２とが、周方向に交互に並ぶように形成してある。
又、第１実施形態と同様に、下流側ノズル列Ｎｄの各筒状ガスノズル２の先端は、前記軸心方向視にて、外側燃焼筒５と内側燃焼筒４との間に位置するように、下流側ノズル列Ｎｄの各筒状ガスノズル２により、ガス燃料Ｇを、内側空気流路３ｉの出口から吐出される燃焼用空気Ａ及び外側空気流路３ｏの出口から吐出される燃焼用空気Ａに対して吐出するようにしてある。
【００４５】
外側空気流路３ｏの出口側には、空気吐出手段Ｔとしての外側バッフル板１３（空気吐出部に相当する）を、前記軸心方向視にて、周方向において、隣接する筒状ガスノズル２の間に燃焼用空気Ａを吐出するように設けてある。
説明を加えると、外周部に８個の空気吐出用切り欠き１３ｗを周方向に均等に分散させて形成した環状の外側バッフル板１３を、前記軸心方向視にて、周方向において、空気吐出用切り欠き１３ｗが隣接する筒状ガスノズル２の略中央に位置する姿勢で、外側空気流路３ｏの出口側に嵌め込んで設けてある。
【００４６】
外周部に８個の空気吐出用切り欠き１４ｗを周方向に均等に分散させて形成した環状の内側バッフル板１４を、前記軸心方向視にて、周方向において、空気吐出用切り欠き１４ｗが筒状ガスノズル２と同位置に位置する姿勢で、内側空気流路３ｉの出口側に嵌め込んで設けてある。
【００４７】
そして、上述のように構成したバーナＢを、第１実施形態と同様に、加熱室３２における上端側の中央部に、ガス供給筒１の先端を燃焼空間３４に臨ませた状態で、且つ、前記軸心方向視にて、各筒状ガスノズル２の先端が、最内周環状水管列Ｐｉの隣接する水管３３同士の略中央における加熱室３２の中心側の位置に位置する状態で配設してある。
【００４８】
つまり、複数の水管３３を周方向に均等に分散した最内周環状水管列Ｐｉと、その最内周環状水管列Ｐｉの水管３３と同数の複数の筒状ガスノズル２を周方向に均等に分散した上流側ノズル列Ｎｕ及び下流側ノズル列Ｎｄ夫々とを、前記軸心方向視にて、各筒状ガスノズル２の先端が最内周環状水管列Ｐｉにおける隣接する水管３３同士の略中央に位置する相対位置関係にて配設することにより、全ての筒状ガスノズル２にて形成される火炎Ｆが同一の条件で水管３３により冷却されるように構成してある。
【００４９】
第３実施形態のバーナＢにおいては、上流側ノズル列Ｎｕ及び下流側ノズル列Ｎｄ夫々において、第１実施形態と同様に、各列の筒状ガスノズル２の設置本数と同数（８個）に分割される状態で、火炎Ｆが形成されるが、前記軸心方向視にて、各筒状ガスノズル２から噴出されたガス燃料噴出流の両側を、燃焼用空気Ａが流れるので、筒状ガスノズル２から噴出されたガス燃料Ｇは、前記軸心方向視にて、その両側から燃焼用空気Ａが供給されて、二股状の火炎Ｆが形成される状態で燃焼する。そして、二股状の火炎Ｆの両側の火炎は、夫々、前記軸心方向視にて、ガス供給筒１の径方向に対してガス供給筒１の周方向側に傾く状態となるように形成される。
【００５０】
従って、第３実施形態の貫流ボイラでは、第１実施形態と同様に、各筒状ガスノズル２にて、火炎形成方向が安定した状態で火炎Ｆが形成されるので、全ての筒状ガスノズル２にて形成される火炎Ｆを、最内周環状水管列Ｐｉの水管３３によって予め定めた条件通りに、安定して冷却することができる。従って、窒素酸化物の発生量の低減と一酸化炭素の発生量の低減を両立させることができる。
又、上流側ノズル列Ｎｕ及び下流側ノズル列Ｎｄ夫々においては、各筒状ガスノズル２により、火炎Ｆは、前記軸心方向視にて、最内周環状水管列Ｐｉの隣接する水管３３同士の略中央における加熱室３２の中心側の位置において、二股状に形成されるので、二股状の火炎Ｆの両側の火炎は、ガス供給筒１の径方向に対してガス供給筒１の周方向側に傾くように形成されるので、燃焼量が小さくて火炎Ｆが短いときは、火炎Ｆが最内周環状水管列Ｐｉの水管３３に当たり難く、水管による火炎の冷却が抑制され、一方、燃焼量が大きくなって火炎Ｆが長くなるほど、火炎Ｆが最内周環状水管列Ｐｉの水管３３に当たり易くなり、火炎Ｆが水管３３により冷却され易くなる。従って、燃焼量の変更に伴って火炎Ｆの長さが変化しても、火炎Ｆを、窒素酸化物の発生量を低減すると共に一酸化炭素の発生量を低減すべく、適度に冷却することができる。
【００５２】
〔第４実施形態〕
以下、第４実施形態を説明する。
第４実施形態においては、環状水管群Ｐと複数の筒状ガスノズル２との配置形態が第３実施形態と異なる以外は、第３実施形態と同様に構成してあるので、以下では、主として、第３実施形態と異なる構成について説明する。
即ち、図１１に示すように、第４実施形態においては、環状水管群Ｐは、第３実施形態と同様に、最内周環状水管列Ｐｉ、中間環状水管列Ｐｍ及び最外周環状水管列Ｐｏの３列状に形成してあるが、上流側ノズル列Ｎｕ及び下流側ノズル列Ｎｄ夫々において、筒状ガスノズル２を、前記軸心方向視にて、その長手方向をガス供給筒１の径方向に沿わせ、且つ、その先端を最内周環状水管列Ｐｉの水管３３に対向させた状態でガス供給筒１に設けてある。
【００５３】
従って、上流側ノズル列Ｎｕ及び下流側ノズル列Ｎｄ夫々において、各火炎Ｆが、前記軸心方向視にて、水管３３に真正面に対向する位置にて二股状に形成される状態で、火炎Ｆが８分割状に形成される。
そして、各火炎Ｆは、火炎形成方向が安定した状態で形成される状態で、前記軸心方向視にて、二股の間に環状水管列Ｐｉの水管３３が位置する二股状に形成されることから、火炎Ｆは、水管３３により、過度に冷却されることなく適度に冷却されることになり、全ての筒状ガスノズル２にて形成される火炎Ｆを、最内周環状水管列Ｐｉの水管３３によって、窒素酸化物の発生量を低減すると共に一酸化炭素の発生量を低減すべく定めた条件通りに、安定して冷却することができる。従って、窒素酸化物の発生量の低減と一酸化炭素の発生量の低減を両立させることができる。
【００８３】
〔別実施形態〕
次に別実施形態を説明する。
（イ） 上記の各実施形態において、ガス供給筒１の周方向に間隔を隔てて並ぶ筒状ガスノズル２の本数と、最内周環状水管列Ｐｉの水管３３の本数とを同じにする場合について例示したが、ガス供給筒１の周方向に間隔を隔てて並ぶ筒状ガスノズル２の本数と、最内周環状水管列Ｐｉの水管３３の本数とを異ならせても良い。
例えば、筒状ガスノズル２の本数を、最内周環状水管列Ｐｉの水管３３の本数の半数にして、複数の筒状ガスノズル２を、前記軸心方向視にて、各筒状ガスノズル２の先端が、最内周環状水管列Ｐｉの隣接する水管３３同士の中間部のうち１個おきの中間部に位置する状態で設けても良い。
【００８４】
（ロ） 上記の第１〜第４の各実施形態において、上流側ノズル列Ｎｕと下流側ノズル列Ｎｄとにおいて、ガス供給筒１の周方向に並ぶ筒状ガスノズル２の並び位相を異ならせても良い。
例えば、上流側ノズル列Ｎｕにおいては、筒状ガスノズル２を、前記軸心方向視にて、その先端を最内周環状水管列Ｐｉの水管３３に対してガス供給筒１の周方向にずらした状態でガス供給筒１に設け、下流側ノズル列Ｎｄにおいては、筒状ガスノズル２を、前記軸心方向視にて、その先端を最内周環状水管列Ｐｉの水管３３に対して真正面に向けた状態でガス供給筒１に設ける。
【００９０】
（ハ） 環状水管群Ｐにおける複数の水管３３の配置形態は、上記の各実施形態において例示した配置形態に限定されるものではない。
例えば、複数の水管３３を、前記軸心方向視にて、１列で環状に並べても良い。
あるいは、前記軸心方向視にて、最内周部にて、複数の水管３３が環状に並ぶ最内周環状水管列Ｐｉが形成され、最内周環状水管列Ｐｉの外側では、複数の水管３３を、環状の列を形成せずに不規則に並べても良い。
【図面の簡単な説明】
【図１】 第１実施形態に係る貫流ボイラの縦断面図
【図２】 第１実施形態に係る貫流ボイラの横断底面図
【図３】 図２のイ−イ方向における貫流ボイラのバーナの矢視図
【図４】 第１実施形態に係る貫流ボイラのバーナの要部の斜視図
【図５】 第２実施形態に係る貫流ボイラの横断底面図
【図６】 第３実施形態に係る貫流ボイラの縦断面図
【図７】 第３実施形態に係る貫流ボイラの横断底面図
【図８】 図７のロ−ロ方向における貫流ボイラのバーナの矢視図
【図９】 第３実施形態に係る貫流ボイラのバーナの要部の斜視図
【図１０】 第３実施形態に係る貫流ボイラのバーナの一部切り欠き底面図
【図１１】 第４実施形態に係る貫流ボイラの横断底面図
【図１２】 従来の貫流ボイラの縦断面図
【図１３】 従来の貫流ボイラのバーナの縦断面図
【符号の説明】
１ ガス供給筒
２ 筒状ガスノズル
３ 空気流路
３ｉ 内側空気流路
３ｏ 外側空気流路
１１ 旋回手段
１２ 旋回手段
１３ 空気吐出部
１６ 旋回手段
１７ 空気吐出部
３２ 加熱室
３３ 水管
３４ 燃焼空間
Ａ 燃焼用空気
Ｂ バーナ
Ｇ ガス燃料
Ｆ 火炎
Ｎｄ 下流側ノズル列
Ｎｕ 上流側ノズル列
Ｐ 環状水管群
Ｐｉ 最内周環状水管列
Ｔ 空気吐出手段[0001]
BACKGROUND OF THE INVENTION
In the present invention, a plurality of water pipes that allow water to be heated to flow inside a cylindrical heating chamber are arranged so that their longitudinal directions are along the axial direction of the heating chamber. It is provided in an annular shape when viewed from the heart
The present invention relates to a once-through boiler configured such that a burner is disposed at a central portion on one end side in the axial direction in the heating chamber, and gas fuel is combusted using a central space of the annular water tube group as a combustion space.
[0002]
[Prior art]
In such a once-through boiler, the burner is used to stably burn the gas fuel while making the flame temperature as low as possible, thereby reducing the amount of nitrogen oxide (NOx) and carbon monoxide (CO) generated. Is desired.
In order to achieve such an object, a flame formed by a burner is cooled by a water pipe. In other words, the lower the flame temperature, the smaller the amount of nitrogen oxide generated, so the flame formed by the burner is cooled by a water tube to lower the flame temperature and reduce the amount of nitrogen oxide generated. Try to reduce. On the other hand, even if the flame formed by the burner is cooled by the water pipe, if the flame is cooled too much, the combustion becomes unstable and the amount of carbon monoxide generated increases. Therefore, even if the flame is cooled with a water pipe in order to reduce the amount of nitrogen oxides generated, the amount of carbon monoxide generated should not be overcooled so that stable combustion can be maintained. Need to be reduced.
[0003]
  In such a once-through boiler, in order to cool a flame formed by a burner with a water pipe, in the past,12As shown in FIG. 4, the burner B is configured to be dispersed in the circumferential direction to form the flame F, and the burner B and the water tube group P are arranged so that the positional relationship of each flame F with respect to the corresponding water tube 33 is all. Some flames F are arranged so as to be substantially the same, and each of the flames F formed in a distributed manner is intended to be cooled uniformly by the water pipe 33 (see, for example, JP-A-11-325402).
  Conventionally, as the burner B used in such a once-through boiler, generally,13As shown in FIG. 5, a plurality of gas ejection holes 38 are formed in the circumferential wall on the distal end side of the gas supply cylinder 37 whose distal end is closed, dispersed in the circumferential direction, and the gas ejected from the plurality of gas ejection holes 38 An air flow path 39 for discharging combustion air A to the fuel G is provided in an annular shape on the outer periphery of the gas supply cylinder 37 as viewed in the axial direction of the gas supply cylinder 37, and the gas ejection holes 38 adjacent in the circumferential direction are provided. The flames F are formed in a divided manner with each other (see, for example, Japanese Patent Application Laid-Open No. 11-337022).
  And the burner B configured as described above is shown in FIG.12As shown in FIG. 3, the gas supply cylinder 37 is arranged so that the longitudinal direction thereof is along the axial direction of the cylindrical heating chamber 32. The figure12Reference numeral 34 denotes a combustion space for burning gas fuel in the burner B.
[0004]
[Problems to be solved by the invention]
However, in the conventional once-through boiler, the gas fuel is ejected from the gas ejection hole formed in the peripheral wall on the front end side of the gas supply cylinder, so that the gas ejection direction becomes unstable, and as a result, the flame The formation direction becomes unstable, and it is difficult for the flame to hit the water pipe according to predetermined conditions (for example, the contact area and the contact amount of the flame with respect to the water pipe). Or increased flame cooling and unstable combustion, increasing the amount of carbon monoxide generated, reducing the amount of nitrogen oxide generated and reducing the amount of carbon monoxide generated. There was room for improvement in reducing the amount of generation.
That is, when the gas injection hole is formed in the peripheral wall of the gas supply cylinder, it is necessary to secure the inner diameter of the gas injection hole so that a desired gas fuel injection amount is obtained. Since there is a limit even if the thickness is increased, the ratio of the length in the axial direction to the inner diameter of the gas ejection hole is small (usually, the ratio is smaller than 1). The guiding action is weak, the ejection direction of the gas fuel ejected from the gas ejection holes becomes unstable, and the flame formation direction becomes unstable.
Therefore, while reducing the generation amount of nitrogen oxides and reducing the generation amount of carbon monoxide, the annular water tube group and the plurality of gas ejection holes are disposed so that the flame is appropriately cooled. Since the formation direction of the flame becomes unstable, it is difficult for the flame to be cooled according to predetermined conditions, and the cooling of the flame becomes insufficient or excessive.
[0005]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a once-through boiler capable of achieving both a reduction in the generation amount of nitrogen oxides and a reduction in the generation amount of carbon monoxide.
[0006]
[Means for Solving the Problems]
  [Invention of Claim 1]
  According to a first aspect of the present invention, the burner protrudes from the peripheral wall of the gas supply cylinder disposed with its longitudinal direction being along the axial direction, and the peripheral wall on the distal end side of the gas supply cylinder. A plurality of cylindrical gas nozzles that are distributed in the circumferential direction and eject gas fuel flowing in the gas supply cylinder, and are annularly provided on the outer periphery of the gas supply cylinder as viewed in the axial direction. An air flow path for discharging combustion air to the gas fuel ejected from the plurality of cylindrical gas nozzles,
  The annular water tube group and the plurality of cylindrical gas nozzles are arranged in a relative positional relationship in which flames formed by all the cylindrical gas nozzles are cooled by the water tube under the same or substantially the same conditions,
  The air flow path is located on the inner air flow path and the outer periphery of the inner air flow path, and the outlet is located on the rear end side in the axial direction with respect to the outlet of the inner air flow path. And consists of
  An upstream nozzle row in which the plurality of cylindrical gas nozzles are dispersed and arranged in the circumferential direction so as to eject gas fuel to the combustion air discharged from the outlet of the outer air flow path, and the upstream nozzle row Gas fuel is ejected from the combustion air discharged from the outlet of the inner air flow path or the combustion air discharged from the outlet of the outer air flow path, which is located on the tip end side in the axial direction. So as to form a downstream nozzle row distributed in the circumferential direction and arranged in the gas supply cylinder,
  Each cylindrical gas nozzle of the upstream nozzle row has a posture in which the axial center is orthogonal to the axial center of the gas supply tube and the longitudinal direction is along the radial direction of the gas supply tube in the axial direction view. Provided in,
  As the cylindrical gas nozzle of the downstream nozzle row, a cylindrical gas nozzle whose axis is perpendicular to the axis of the gas supply cylinder and whose longitudinal direction is along the radial direction of the gas supply cylinder in the axial direction view And a cylindrical gas nozzle whose axis is inclined forward with respect to a direction perpendicular to the axis of the gas supply cylinder and whose longitudinal direction is along the radial direction of the gas supply cylinder in the axial direction view. The gas supply cylinders are arranged alternately in the circumferential direction.There is in being.
  According to the characteristic configuration of the first aspect, the ejection direction is stabilized from each of the plurality of cylindrical gas nozzles provided on the peripheral wall on the distal end side of the gas supply cylinder so as to protrude from the peripheral wall in the circumferential direction. Since the combustion fuel is discharged from the air flow path with respect to the gas fuel ejected from the plurality of cylindrical gas nozzles in such a state that the ejection direction is stabilized in such a state, each cylindrical gas nozzle Thus, the flame is formed in a state where the flame forming direction is stable.
  And, as described above, since the flame is formed in a state where the flame forming direction is stable at each cylindrical gas nozzle, the annular water tube group and the plurality of cylindrical gas nozzles are connected to all the cylindrical gas nozzles. When the formed flame is disposed in a relative positional relationship that is cooled by the water pipe under the same or substantially the same conditions, the flame is reduced in advance to reduce the amount of nitrogen oxides generated and the amount of carbon monoxide generated. The flame formed by all the cylindrical gas nozzles is stabilized in the water tube under the same or substantially the same conditions as the conditions (for example, the contact area and the contact amount of the flame with respect to the water pipe) And can be cooled.
  That is, the cylindrical gas nozzle can be increased in length in the axial direction with respect to the inner diameter (the ratio of the length in the axial direction to the inner diameter can be appropriately set to 1 or more). Has a strong effect of guiding the flow of gas fuel, and from the cylindrical gas nozzle, the fuel gas is jetted in a state in which the fuel gas is effectively given straightness and diffusion is suppressed, so that the gas jet from the cylindrical gas nozzle The direction is stable.
  And since each flame is formed in a state where the flame formation direction is stable in each cylindrical gas nozzle, all the cylindrical gas nozzles are reduced in order to reduce the generation amount of nitrogen oxide and the generation amount of carbon monoxide. When the annular water tube group and the plurality of cylindrical gas nozzles are arranged in a predetermined relative positional relationship so that the flame formed by the same or substantially the same is appropriately cooled, all the cylindrical gas nozzles The formed flame can be stably cooled according to predetermined conditions.
  In addition, since the fuel gas is jetted in a state in which the gas gas is effectively made to go straight by the cylindrical gas nozzle and the diffusion is suppressed, a negative pressure region (a region where the pressure is lower than the surroundings) around the cylindrical gas nozzle. As a result, the combustion gas combusted by the fuel gas ejected from the cylindrical gas nozzle is circulated by the attracting action of the negative pressure region, and the combustion gas is injected into the combustion region of the fuel gas ejected from the cylindrical gas nozzle. By so-called exhaust gas recirculation in which fuel gas is burned while flowing in, the fuel gas can be effectively burnt slowly and the temperature of the flame can be further lowered.
  Therefore, it has become possible to provide a once-through boiler that can achieve both a reduction in the generation amount of nitrogen oxides and a reduction in the generation amount of carbon monoxide.
  Moreover, according to the characteristic structure of Claim 1, the gas fuel injected from the several cylindrical nozzle arranged in the said circumferential direction in an upstream nozzle row is the combustion air discharged from the exit of an outer air flow path. The gas fuel ejected from the plurality of cylindrical gas nozzles arranged in the circumferential direction in the downstream nozzle row located on the distal end side in the axial direction with respect to the upstream nozzle row is It burns with the combustion air discharged from the outlet or the combustion air discharged from the outlet of the outer air flow path.
  That is, the gas fuel ejected from the plurality of cylindrical nozzles arranged in the circumferential direction in the upstream nozzle row is burned with combustion air discharged from the outlet of the outer air flow path, and primary combustion is performed. Gas fuel is supplied from a plurality of cylindrical gas nozzles arranged in the circumferential direction in the downstream nozzle row to the flame formed by the primary combustion, and the gas fuel is discharged from the outlet of the inner air flow path. Combustion with combustion air or combustion air discharged from the outlet of the outer air flow path to cause multi-stage combustion prevents nitrogen from being generated locally in the flame. Oxide generation is suppressed.
  Therefore, since the generation of NOx can be suppressed by the multistage combustion, the generation amount of nitrogen oxide can be further reduced..
[0007]
  [Claims2Description of Invention]
  Claim2The characteristic configuration described in (1) is that the plurality of cylindrical gas nozzles are provided so as to be dispersed in the circumferential direction so as to form flames in a divided manner by those adjacent in the circumferential direction.
  Claim2According to the characteristic configuration described in (1), a plurality of flames are formed in the circumferential direction in a state where the flame formation direction of each flame is stable, and each flame is independently cooled by the water pipe.
  That is, when the annular water tube group and the plurality of cylindrical gas nozzles are arranged in a relative positional relationship in which the flames formed by all the cylindrical gas nozzles are cooled by the water tube under the same or substantially the same conditions, Compared to the case where the flames are formed in the circumferential direction, the flames are formed in a dispersed manner in the circumferential direction so that each flame is independently cooled by a water pipe. Interference of adjacent flames in the direction can be suppressed and each flame can be applied to the water pipe according to a predetermined condition, so that the flame formed by all cylindrical gas nozzles can be Cooling can be performed satisfactorily.
  Moreover, by forming a plurality of flames dispersed in the circumferential direction, the inflow of combustion gas to the combustion zone of each cylindrical gas nozzle can be achieved as compared with the case where the flames are formed in a continuous state in the circumferential direction. Since it can promote and exhaust gas recirculation can be performed more effectively, the temperature of a flame can be lowered further.
  Therefore, the generation amount of nitrogen oxides and the generation amount of carbon monoxide can be further reduced.
[0008]
  [Claims3Description of Invention]
  Claim3In the characteristic configuration described in the above, an innermost circumferential annular water tube row in which the same number of the water tubes as the plurality of cylindrical gas nozzles are annularly formed is formed on the innermost circumferential side in the annular water tube group,
  The cylindrical gas nozzle has its longitudinal direction along the radial direction of the gas supply cylinder, as viewed in the axial direction, and the tip thereof in the circumferential direction with respect to the water pipe of the innermost annular water pipe row Provided in the gas supply cylinder in a shifted state,
  From the cylindrical gas nozzle, the flame formed by the combustion of the gas fuel ejected from the cylindrical gas nozzle is inclined toward the circumferential side with respect to the radial direction when viewed in the axial direction. An air discharge means for discharging combustion air from the outlet of the air flow path with respect to the jetted gas fuel is provided.
  That is, in such a once-through boiler, the combustion amount of the burner is changed according to the heat load, but the length of the flame formed by the combustion of the gas fuel ejected from the cylindrical gas nozzle in accordance with the change of the combustion amount. Therefore, even if the length of the flame changes, it is necessary to cool the flame appropriately in order to reduce the generation amount of nitrogen oxide and the generation amount of carbon monoxide, It is desired to reduce the size of the once-through boiler by narrowing the distance between the tip of the cylindrical gas nozzle and the water tube of the innermost circumferential annular water tube row in the direction along the radial direction of the gas supply tube.
  Therefore, the cylindrical gas nozzle has its longitudinal direction aligned with the radial direction of the gas supply cylinder as viewed in the axial direction, and its tip is shifted in the circumferential direction with respect to the water pipe of the innermost circumferential annular water pipe row. The flame formed by the combustion of the gas fuel ejected from the cylindrical gas nozzle is inclined to the circumferential direction side with respect to the radial direction as viewed in the axial direction. Thus, by providing air discharge means for discharging combustion air from the outlet of the air flow path to the gas fuel ejected from the cylindrical gas nozzle, the tip of the cylindrical gas nozzle and the outermost end in the radial direction are provided. When the distance between the water pipes in the inner circumferential water pipe row is narrow but the combustion amount is small and the flame is short, the flame does not easily hit the water pipe, and the cooling of the flame by the water pipe is suppressed. Increased flame length It can be said that the flame easily hits the water pipe, so that the flame can be easily cooled by the water pipe. In order to reduce the generation amount and reduce the generation amount of carbon monoxide, it is possible to cool appropriately.
  By the way, the gas supply cylinder has a cylindrical gas nozzle in which the longitudinal direction is along the radial direction of the gas supply cylinder and the tip thereof faces the water pipe of the innermost annular water tube row when viewed in the axial direction. It is assumed that the flame formed by the combustion of the gas fuel ejected from the cylindrical gas nozzle in the axial direction view is formed in a direction along the radial direction. If the distance between the tip of the cylindrical gas nozzle and the water tube of the innermost circumferential annular water tube row in the direction along the radial direction is narrowed, the flame easily hits the water tube even when the combustion amount is small and the flame is short. This is disadvantageous in shortening the interval because there is a risk that the combustion becomes unstable.
  Accordingly, it is possible to reduce the size of the once-through boiler while simultaneously reducing the generation amount of nitrogen oxides and the generation amount of carbon monoxide.
[0009]
  [Claims4Description of Invention]
  Claim4In the characteristic configuration described in the above, on the outlet side of the outer air flow path, an air discharge unit as the air discharge unit is burned between the cylindrical gas nozzles adjacent in the circumferential direction as viewed in the axial direction. It exists in being provided so that the working air may be discharged.
  Claim4According to the characteristic configuration described in the above, since the combustion air flows on both sides of the gas fuel jet flow jetted from the cylindrical gas nozzle in the axial direction view, the gas fuel jetted from the cylindrical gas nozzle is Combustion air is supplied from both sides as viewed in the axial direction, and combustion occurs in a state where a flame having a bifurcated shape is formed. Then, the flames on both sides of the flame having a bifurcated shape are formed so as to be inclined in the circumferential direction with respect to the radial direction as viewed in the axial direction.
  In addition, by burning the gas fuel ejected from the cylindrical gas nozzle in a state where a flame having a bifurcated shape is formed, the surface area of the flame is increased and the cooling action of the flame is increased. The generation of nitrogen oxides can be further suppressed.
  Therefore, in order to make the once-through boiler smaller while simultaneously reducing the generation amount of nitrogen oxides and the generation amount of carbon monoxide, it is necessary to further reduce the generation amount of nitrogen oxides. A preferred specific configuration can be provided.
[0010]
  [Claims5Description of Invention]
  Claim5The swirling means as the air discharge means is provided on the outlet side of the air flow path so that the combustion air flowing in the air flow path is swung and discharged from the outlet. It is in.
  Claim5According to the characteristic configuration described in (4), the combustion air is discharged in a state of being swirled from the outlet of the air flow path and is supplied to the gas fuel ejected from the cylindrical gas nozzle. The flame formed by the combustion of the gas fuel ejected from the cylindrical gas nozzle by the turning force is formed so as to be inclined toward the circumferential direction with respect to the radial direction when viewed in the axial direction. .
  Moreover, since the combustion air is discharged while being swirled from the outlet of the air flow path, the mixed state of the gas fuel and the combustion air is promoted, and the stability of combustion is improved. Can be further suppressed.
  Therefore, in order to further reduce the generation amount of carbon monoxide in reducing the size of the once-through boiler while simultaneously reducing the generation amount of nitrogen oxides and the generation amount of carbon monoxide. A preferred specific configuration can be provided.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described.
As shown in FIG. 1 and FIG. 2, a cylindrical can 31 is provided with a cylindrical can 31 whose axial direction is directed vertically, and a cylindrical heating chamber in which the axial direction is directed vertically. 32, and a plurality of water pipes 33 through which water to be heated flows are arranged in the cylindrical heating chamber 32 so that each longitudinal direction thereof is along the axial direction of the heating chamber 32. A burner B is disposed in the center of one end side (upper end side) in the axial direction in the heating chamber 32 to burn the central space of the annular water tube group P. The space 34 is configured to burn the gas fuel G.
[0013]
And in this invention, as shown also in FIG.3 and FIG.4, the burner B is the gas supply cylinder 1 arrange | positioned along a longitudinal direction in the said axial direction, and the front end side of the gas supply cylinder 1 A plurality of cylindrical gas nozzles 2 that are provided in the peripheral wall so as to protrude from the peripheral wall in a circumferential direction and jet gas fuel G flowing in the gas supply cylinder 1, and gas supply in the axial direction view An annular water tube group P is provided with an air flow path 3 that is annularly provided on the outer periphery of the cylinder 1 and discharges combustion air A to the gas fuel G ejected from the plurality of cylindrical gas nozzles 2. And the plurality of cylindrical gas nozzles 2 are arranged in a relative positional relationship in which the flames F formed by all the cylindrical gas nozzles 2 are cooled by the water pipe 33 under the same or substantially the same conditions.
[0014]
When the explanation is added, the innermost circumferential annular water pipe row Pi in which the same number of water pipes 33 as the plurality of cylindrical gas nozzles 2 of the burner B are annularly formed is formed on the inner circumferential side of the annular water pipe group P. Are formed in two rows as viewed in the axial direction so that the outermost circumferential annular water tube row Po is formed.
The innermost circumferential annular water pipe row Pi is arranged in such a manner that a plurality of water pipes 33 are evenly distributed in the circumferential direction, and adjacent water pipes 33 are connected by a fin-like member 38 with the lower side open. The outermost circumferential annular water tube row Po is formed in such a manner that the plurality of water tubes 33 are arranged in a state of being evenly distributed in the circumferential direction, and adjacent water tubes 33 are connected to each other by a fin-like member 38 with the upper side opened. Formed.
Then, the combustion gas E of the burner B is caused to flow between the innermost circumferential annular water pipe row Pi and the outermost circumferential annular water pipe row Po from the lower side of the innermost circumferential annular water pipe row Pi, and flowed between them. Thereafter, a flow path for the combustion gas E is formed so as to flow out from the upper side of the outermost circumferential annular water tube row Po and to be discharged through the exhaust passage 35.
[0015]
A ring-shaped steam drum 36 that is continuous in the circumferential direction is provided at the upper end of the can 31, and a ring-shaped water drum 37 that is continuous in the circumferential direction is provided at the lower end, so that the upper end of each water pipe 33 of the annular water pipe group P is provided. The water drum 33 is connected to the steam drum, the lower end of each water pipe 33 of the annular water pipe group P is connected to the water drum 37, and water to be heated is supplied to the water drum 37 by a pump (not shown). Is made to flow upward to the steam drum 36 and heated by the burner B, thereby generating steam and supplying the generated steam to the steam demand destination.
[0016]
Next, the burner B will be described with reference to FIGS.
In the first embodiment, the cylindrical gas nozzle 2 has its longitudinal direction aligned with the radial direction of the gas supply cylinder 1 as viewed in the axial direction, and the tip of the cylindrical gas nozzle 2 is the water pipe of the innermost annular water pipe row Pi. A flame F formed by combustion of the gas fuel G ejected from the cylindrical gas nozzle 2 when viewed in the axial direction and provided in the gas supply cylinder 1 in a state shifted from the circumferential direction of the gas supply cylinder 1 with respect to 33. From the outlet of the air flow path 3 with respect to the gas fuel G ejected from the cylindrical gas nozzle 2 so as to be inclined to the circumferential direction side of the cylindrical gas nozzle 2 with respect to the radial direction of the gas supply cylinder 1 Air discharge means T for discharging combustion air A is provided.
[0017]
Moreover, the air flow path 3 is located in the inner air flow path 3i and the outer peripheral part of the inner air flow path 3i, and the outlet is located on the rear end side in the axial direction with respect to the outlet of the inner air flow path 3i. The outer air flow path 3o is configured to disperse the plurality of cylindrical gas nozzles 2 in the circumferential direction so as to eject the gas fuel G to the combustion air A discharged from the outlet of the outer air flow path 3o. The upstream nozzle row Nu and the combustion air A and the outer air channel 3o discharged from the outlet of the inner air flow path 3i, which are positioned on the front end side in the axial direction with respect to the upstream nozzle row Nu. The gas supply cylinder 1 is provided so as to form a downstream nozzle row Nd that is dispersed and arranged in the circumferential direction so as to eject the gas fuel G to the combustion air A discharged from the outlet.
[0018]
When the explanation is added, the cylindrical inner combustion cylinder 4 is provided on the outer side of the cylindrical gas supply cylinder 1 whose front end is closed, and is provided coaxially in a state where the front end is retracted from the front end of the gas supply cylinder 1. Further, a cylindrical outer combustion cylinder 5 is provided on the outer side of the inner combustion cylinder 4 so as to be coaxial with the tip of the inner combustion cylinder 4 being retracted from the tip of the inner combustion cylinder 4. An annular inner air flow path 3 i is formed between the gas supply cylinder 1 and the inner combustion cylinder 4 as viewed in the axial direction, and the shaft is interposed between the inner combustion cylinder 4 and the outer combustion cylinder 5. An annular outer air flow path 3o is formed when viewed from the center.
Both ends of the inner combustion cylinder 4 and the outer combustion cylinder 5 are open, and the rear end of the inner combustion cylinder 4 is positioned in front of the rear end of the outer combustion cylinder 5, so that the inside combustion cylinder 4, that is, the inner air The flow path 3 i is communicated with the outer combustion cylinder 5.
[0019]
The rear end of the gas supply cylinder 1 protrudes beyond the rear end of the outer combustion cylinder 5, the rear end side of the gas supply cylinder 1 protrudes outside the wind box 6, and the rear of the outer combustion cylinder 5 An air chamber 7 is formed in the wind box 6 so as to cover the end opening, and communicates with the outer air flow path 3o and the inner air flow path 3i.
[0020]
The air supply path 9 through which the combustion air A is introduced from the blower 8 is connected to the wind box 6 so as to communicate with the air chamber 7, and the combustion air A is supplied to the air chamber 7 through the air supply path 9. The gas chamber G is configured to be supplied to the outer air flow channel 3o and the inner air flow channel 3i through the air chamber 7, and a gas fuel G such as city gas is introduced into the rear end of the gas supply tube 1. The gas fuel supply path 10 is connected.
[0021]
In the gas supply cylinder 1, a plurality of cylindrical gas nozzles 2 having the same length are provided on the peripheral wall of the front end side of the outer combustion cylinder 5 and covered with the inner combustion cylinder 4. The upstream nozzle row Nu is formed in a state of penetrating and projecting from the inner combustion cylinder 4 and being evenly distributed in the cylinder circumferential direction and arranged in a line. Further, in the gas supply cylinder 1, the same number of cylindrical gas nozzles 2 as the upstream nozzle row Nu are provided on the peripheral wall of the tip side from the tip of the inner combustion cylinder 4, and the cylindrical gas nozzles 2 in the upstream nozzle row Nu in the circumferential direction. The downstream nozzle row Nd is formed in a state of being arranged in a row with the same phase as the arrangement phase of.
[0022]
Each cylindrical gas nozzle 2 of the upstream nozzle row Nu has an attitude in which the axis is orthogonal to the axis of the gas supply cylinder 1 and the longitudinal direction is along the radial direction of the gas supply cylinder 1 when viewed in the axial direction. The gas fuel G is supplied in a direction perpendicular to the axis of the gas supply cylinder 1 and along the radial direction of the gas supply cylinder 1 as viewed in the axial direction. It is supposed to erupt. Further, the tip of each cylindrical gas nozzle 2 of the upstream nozzle row Nu is positioned between the outer combustion tube 5 and the inner combustion tube 4 in the axial direction view, so that the upstream nozzle row Nu has Each cylindrical gas nozzle 2 discharges the gas fuel G to the combustion air A discharged from the outlet of the outer air flow path 3o.
[0023]
Further, in the downstream nozzle row Nd, a cylindrical gas nozzle 2 whose axis is orthogonal to the axis of the gas supply cylinder 1 and whose longitudinal direction is along the radial direction of the gas supply cylinder 1 when viewed in the axial direction, A cylindrical gas nozzle 2 whose axis is inclined forward with respect to a direction perpendicular to the axis of the gas supply cylinder 1 and whose longitudinal direction is along the radial direction of the gas supply cylinder 1 when viewed in the axial direction. Are arranged alternately in the circumferential direction. That is, the downstream nozzle row Nd is a cylindrical gas nozzle 2 that ejects gas fuel G in a direction orthogonal to the axis of the gas supply cylinder 1 and along the radial direction of the gas supply cylinder 1 as viewed in the axial direction. A cylindrical gas nozzle 2 that inclines forward with respect to a direction perpendicular to the axis of the gas supply cylinder 1 and jets gas fuel G in a direction along the radial direction of the gas supply cylinder 1 when viewed in the axial direction; They are formed so as to be arranged alternately in the circumferential direction.
The tip of each cylindrical gas nozzle 2 in the downstream nozzle row Nd is positioned between the outer combustion tube 5 and the inner combustion tube 4 in the axial direction view so that the downstream nozzle row Nd Gas fuel G is discharged from each cylindrical gas nozzle 2 to combustion air A discharged from the outlet of the inner air passage 3i and combustion air A discharged from the outlet of the outer air passage 3o. It is.
[0024]
On the outlet side of the inner air flow path 3i, an inner swirl vane 11 (corresponding to the swirl means) serving as the air discharge means T is swirled to discharge the combustion air A flowing through the inner air flow path 3i from the outlet. Similarly, the outer swirl vane 12 (corresponding to the swirl means) as the air discharge means T is swirled on the outlet side of the outer air flow path 3o with the combustion air A flowing through the outer air flow path 3o. It is provided to discharge from the outlet.
[0025]
In addition, although the number of the water pipes 33 which comprise the annular water pipe group P is set based on the heat transfer area set according to the capability of the once-through boiler, in the first embodiment, for example, the innermost circumferential annular water pipe row Pi The number of water pipes 33 constituting the annular water pipe group P is set to 13, the number of water pipes 33 constituting the outermost circumferential annular water pipe row Po is set to 17, and the number of water pipes 33 constituting the annular water pipe group P is set to 30.
The number of the cylindrical gas nozzles 2 constituting each of the upstream nozzle row Nu and the downstream nozzle row Nd is 13, which is the same number as the water pipes 33 constituting the innermost circumferential annular water pipe row Pi.
[0026]
And, with the gas burner B configured as described above at the center on the upper end side in the heating chamber 32 and the tip of the gas supply cylinder 1 facing the combustion space 34, and in the axial direction view, The tip of each cylindrical gas nozzle 2 is disposed in a state of being positioned at the center side position of the heating chamber 32 at the approximate center between the adjacent water pipes 33 of the innermost circumferential annular water pipe row Pi.
[0027]
That is, the innermost annular water pipe row Pi in which the plurality of water pipes 33 are evenly distributed in the circumferential direction, and the same number of cylindrical gas nozzles 2 as the water pipes 33 in the innermost peripheral annular water pipe row Pi are evenly distributed in the circumferential direction. When the upstream nozzle row Nu and the downstream nozzle row Nd are respectively viewed in the axial direction, the tips of the cylindrical gas nozzles 2 are positioned at the approximate center between the adjacent water pipes 33 in the innermost annular water pipe row Pi. The flame F formed by all the cylindrical gas nozzles 2 is arranged so that the positional relationship of each flame F with respect to the corresponding water pipe 33 is substantially the same for all the flames F. Are cooled by the water pipe 33 under the same conditions.
[0028]
In the burner B configured as described above, the gas fuel G is combusted as described below.
The gas fuel G ejected from the upstream nozzle row Nu is burned by the combustion air A discharged from the outlet of the outer air passage 3o to perform primary combustion, and from the downstream nozzle row Nd. Of the combustion air A discharged from the outlet of the outer air passage 3o, the combustion air A remaining from the primary combustion and the combustion air discharged from the outlet of the inner air passage 3i Combustion is performed at A, and secondary combustion is performed.
The ratio of the amount of the gas fuel G ejected from the upstream nozzle row Nu and the amount of the gas fuel G ejected from the downstream nozzle row Nd is approximately 1: 1, and the outer air flow passage 3o crosses the flow path. By making the area larger than the cross-sectional area of the inner air flow path 3i, in the primary combustion, the excess air ratio is set to about 2.0 and the lean combustion is performed, and the primary combustion and the secondary combustion are performed. For the combined combustion, the excess air ratio is set to about 1.2.
[0029]
Since the combustion air A is discharged in a swirling state from the outlet of the outer air passage 3o with respect to the gas fuel G ejected in a divided state from the 13 cylindrical gas nozzles 2 of the upstream nozzle row Nu, the upstream side With the 13 cylindrical gas nozzles 2 of the side nozzle row Nu, the flames F are tilted toward the circumferential direction side of the gas supply cylinder 1 with respect to the radial direction of the gas supply cylinder 1 as viewed in the axial direction. F is formed in 13 divisions.
[0030]
Similarly, the combustion air A is discharged from the outlets of the inner air passage 3i and the outer air passage 3o with respect to the gas fuel G ejected in a divided state from the thirteen cylindrical gas nozzles 2 of the downstream nozzle row Nd. Since the gas is discharged in a swirling state, each of the flames F is directed to the gas supply cylinder 1 with respect to the radial direction of the gas supply cylinder 1 as viewed in the axial direction by the 13 cylindrical gas nozzles 2 in the downstream nozzle row Nd. The flame F is formed in 13 divisions in a state inclined to the circumferential direction side.
In the downstream nozzle row Nd, the gas nozzles 2 having different ejection directions of the gas fuel G are alternately arranged in the circumferential direction, so that the flames F formed in the gas nozzles 2 adjacent in the circumferential direction are formed further apart. Therefore, the separated state of the flame F becomes clearer.
[0031]
In each of the upstream nozzle row Nu and the downstream nozzle row Nd, the gas fuel G is ejected from each cylindrical gas nozzle 2 in a state in which the ejection direction is stable. Since the flame F is formed in a state in which the direction is stable, the amount of nitrogen oxide generated in the flame F formed by all the cylindrical gas nozzles 2 is reduced by the water pipe 33 of the innermost annular water pipe row Pi. At the same time, it is possible to cool stably according to the conditions determined to reduce the amount of carbon monoxide generated. Therefore, it is possible to reduce both the amount of nitrogen oxides generated and the amount of carbon monoxide generated.
[0032]
Moreover, in each of the upstream nozzle row Nu and the downstream nozzle row Nd, the flame F is caused by the cylindrical gas nozzles 2 between the adjacent water pipes 33 of the innermost circumferential water pipe row Pi in the axial direction view. When the flame F is short and the flame F is short, it is formed so as to be inclined from the center side position of the heating chamber 32 at the substantially center to the circumferential direction side of the gas supply cylinder 1 with respect to the radial direction of the gas supply cylinder 1. The flame F hardly hits the water pipe 33 of the innermost circumferential annular water pipe row Pi, and the cooling of the flame by the water pipe is suppressed. On the other hand, as the combustion amount increases and the flame F becomes longer, the flame F becomes the innermost circumferential annular water pipe row. It becomes easy to hit the Pi water pipe 33, and the flame F is easily cooled by the water pipe 33. Therefore, even if the length of the flame F changes with the change of the combustion amount, the flame F is cooled appropriately in order to reduce the generation amount of nitrogen oxide and the generation amount of carbon monoxide. Can do.
[0033]
The gas fuel G is ejected from the 13 tubular gas nozzles 2 of the downstream nozzle row Nd arranged at intervals in the circumferential direction of the cylinder in a state where the straight traveling performance is effectively given, so that the front space of the gas supply cylinder 1 Since a negative pressure region is formed over the peripheral space of each cylindrical gas nozzle 2 from the front, the space in front of the gas supply tube 1 that becomes the negative pressure region and the cylindrical gas nozzle 2 as shown in FIG. The gas fuel G ejected from the cylindrical gas nozzle 2 of the downstream nozzle row Nd is efficiently circulated through the peripheral space of the downstream nozzle row Nd, and is ejected from the cylindrical gas nozzle 2 of the downstream nozzle row Nd. The gas fuel G can be burned effectively slowly while the combustion gas E efficiently flows into the combustion zone of the gas fuel G, and the generation of nitrogen oxides can be further suppressed. Can do.
[0034]
Further, the gas fuel G ejected from the plurality of cylindrical nozzles 2 arranged in the circumferential direction of the gas supply cylinder 1 in the upstream nozzle row Nu is burned by the combustion air A discharged from the outlet of the outer air passage 3o. Primary combustion is performed, and gas fuel G is supplied from a plurality of cylindrical gas nozzles 2 arranged in the circumferential direction of the gas supply cylinder 1 in the downstream nozzle row Nd to the flame F formed by the primary combustion. Then, the gas fuel is burned in the combustion air A discharged from the outlets of the inner air flow path 3i and the outer air flow path 3o, and two-stage combustion is performed. Generation | occurrence | production of a high temperature area | region can be prevented and generation | occurrence | production of nitrogen oxide can be suppressed further.
[0036]
[Second Embodiment]
The second embodiment will be described below.
In the second embodiment, the configuration of the annular water tube group P and the plurality of cylindrical gas nozzles 2 is the same as that of the first embodiment except that the arrangement is different from that of the first embodiment. A configuration different from the first embodiment will be described.
That is, as shown in FIG. 5, in the second embodiment, the annular water tube group P is formed in two rows of the innermost circumferential annular water tube row Pi and the outermost circumferential annular water tube row Po, as in the first embodiment. Although formed, in each of the upstream nozzle row Nu and the downstream nozzle row Nd, the longitudinal direction of the cylindrical gas nozzle 2 is aligned with the radial direction of the gas supply tube 1 in the axial direction view, and The gas supply tube 1 is provided with its tip opposed to the water pipe 33 of the innermost circumferential annular water pipe row Pi.
[0037]
Therefore, in each of the upstream nozzle row Nu and the downstream nozzle row Nd, each flame F is inclined in the circumferential direction of the gas supply tube 1 with respect to the radial direction of the gas supply tube 1 as viewed in the axial direction. The flame F is formed in 13 divisions.
Each flame F is formed in a state in which the flame formation direction is stable, and from a position facing directly in front of the water pipe 33 of the innermost annular water pipe row Pi as viewed in the axial direction. Since it is formed so as to be inclined toward the circumferential direction side of the gas supply cylinder 1 with respect to the radial direction of the supply cylinder 1, the flame F strikes the side of the water pipe 33 and is appropriately cooled without being excessively cooled. In order to reduce the generation amount of nitrogen oxide and the generation amount of carbon monoxide, the flame F formed by all the cylindrical gas nozzles 2 is reduced by the water pipe 33 of the innermost circumferential annular water pipe row Pi. It is possible to cool stably according to defined conditions. Therefore, it is possible to reduce both the amount of nitrogen oxides generated and the amount of carbon monoxide generated.
[0039]
[Third Embodiment]
Hereinafter, a third embodiment will be described.
The third embodiment differs from the first embodiment except that the arrangement of the water pipes 33 in the annular water pipe group P and the number of installed tubular gas nozzles 2 in the burner B and the air discharge means T are different from those of the first embodiment. Since the configuration is the same, the configuration different from the first embodiment will be mainly described below.
[0040]
That is, as shown in FIGS. 6 and 7, the annular water tube group P includes an innermost circumferential annular water tube row Pi in which the same number of water tubes 33 as the plurality of cylindrical gas nozzles 2 of the burner B are arranged in an annular shape on the innermost circumferential side. An outermost circumferential annular water tube row Po is formed on the outermost circumferential side, and a plurality of water tubes are arranged between the innermost circumferential water tube row Pi and the outermost circumferential annular water tube row Po. It is formed in three rows in the axial direction view so that an intermediate annular water tube row Pm in which 33 are arranged in a ring shape is formed.
[0041]
The outermost circumferential annular water tube row Po is formed by arranging a plurality of water tubes 33 in a state of being evenly distributed in the circumferential direction and connecting adjacent water tubes 33 with fin-like members 38 in a state of opening the lower side. The intermediate annular water tube row Pm is also arranged in such a manner that the same number of water tubes 33 as the outermost annular water tube row Po are evenly distributed in the circumferential direction, and adjacent water tubes 33 are finned with their lower sides open. It is formed by connecting with a member 38.
The innermost circumferential annular water pipe row Pi has a plurality of water pipes 33 in the circumferential direction in a state where each water pipe 33 is located at every other intermediate portion of the intermediate portions of adjacent water pipes 33 in the intermediate annular water pipe row Pm. Are uniformly distributed and formed. In the innermost circumferential water pipe row Pi, adjacent water pipes 33 are not connected by the fin-shaped member 38, and the adjacent water pipes 33 are opened.
Then, the combustion gas E of the burner B is passed between the water pipes 33 in the innermost circumferential annular water pipe row Pi, and from the lower side of the intermediate annular water pipe row Pm, the intermediate annular water pipe row Pm and the outermost circumferential annular water pipe row Po. The flow path of the combustion gas E is formed so as to flow in between and flow between them, then flow out from the upper side of the outermost circumferential annular water tube row Po and discharge through the exhaust path 35.
[0042]
The burner B will be described based on FIGS.
The plurality of cylindrical gas nozzles 2 are provided in the gas supply cylinder 1 so as to form the upstream nozzle row Nu and the downstream nozzle row Nd, as in the first embodiment, but the upstream nozzle row Nu and the downstream side The number of installed cylindrical gas nozzles 2 in each of the side nozzle rows Nd is eight different from the first embodiment.
[0043]
As in the first embodiment, each cylindrical gas nozzle 2 in the upstream nozzle row Nu has an axial center orthogonal to the axial center of the gas supply cylinder 1 and the longitudinal direction of the gas supply cylinder 1 as viewed in the axial direction. A gas supply cylinder is provided so as to be in a posture along the radial direction, and gas fuel G is perpendicular to the axis of the gas supply cylinder 1 and viewed in the axial direction by the cylindrical gas nozzles 2 of the upstream nozzle row Nu. 1 is ejected in a direction along the radial direction. Further, the tip of each cylindrical gas nozzle 2 of the upstream nozzle row Nu is positioned between the outer combustion cylinder 5 and the inner combustion cylinder 4 in the axial direction view, as in the first embodiment. Thus, the gas fuel G is discharged to the combustion air A discharged from the outlet of the outer air flow path 3o by each cylindrical gas nozzle 2 of the upstream nozzle row Nu.
[0044]
Similarly to the first embodiment, in the downstream nozzle row Nd, the axis is orthogonal to the axis of the gas supply cylinder 1 and the longitudinal direction is the radial direction of the gas supply cylinder 1 when viewed in the axial direction. The cylindrical gas nozzle 2 and the axial center of the cylindrical gas nozzle 2 are inclined forward with respect to the direction orthogonal to the axial center of the gas supply cylinder 1, and the longitudinal direction is along the radial direction of the gas supply cylinder 1 when viewed in the axial direction. The cylindrical gas nozzles 2 in the posture are provided so as to be alternately arranged in the circumferential direction. That is, the downstream nozzle row Nd is a cylindrical gas nozzle 2 that ejects gas fuel G in a direction orthogonal to the axis of the gas supply cylinder 1 and along the radial direction of the gas supply cylinder 1 as viewed in the axial direction. A cylindrical gas nozzle 2 that inclines forward with respect to a direction perpendicular to the axis of the gas supply cylinder 1 and jets gas fuel G in a direction along the radial direction of the gas supply cylinder 1 when viewed in the axial direction; They are formed so as to be arranged alternately in the circumferential direction.
Similarly to the first embodiment, the tip of each cylindrical gas nozzle 2 in the downstream nozzle row Nd is positioned between the outer combustion cylinder 5 and the inner combustion cylinder 4 in the axial direction view. The gas fuel G is discharged from the outlet of the inner air passage 3i and the combustion air A discharged from the outlet of the outer air passage 3o by the cylindrical gas nozzles 2 of the downstream nozzle row Nd. Is discharged.
[0045]
On the outlet side of the outer air flow path 3o, an outer baffle plate 13 (corresponding to an air discharge portion) as the air discharge means T is disposed between the adjacent cylindrical gas nozzles 2 in the circumferential direction as viewed in the axial direction. It is provided so as to discharge combustion air A between them.
In other words, an annular outer baffle plate 13 formed by uniformly dispersing eight air discharge notches 13w on the outer peripheral portion in the circumferential direction is formed in the circumferential direction as viewed in the axial direction. The notch 13w for use is fitted in the outlet side of the outer air flow path 3o in such a posture that it is positioned substantially at the center of the adjacent cylindrical gas nozzle 2.
[0046]
An annular inner baffle plate 14 formed by uniformly dispersing eight air discharge notches 14w on the outer peripheral portion in the circumferential direction has an air discharge notch 14w in the circumferential direction as viewed in the axial direction. In an attitude located at the same position as the cylindrical gas nozzle 2, it is fitted into the outlet side of the inner air flow path 3 i.
[0047]
And the burner B comprised as mentioned above is the state which made the front-end | tip of the gas supply cylinder 1 face the combustion space 34 in the center part of the upper end side in the heating chamber 32 similarly to 1st Embodiment, and As viewed in the axial direction, the tip of each cylindrical gas nozzle 2 is disposed in a state of being positioned at the center side of the heating chamber 32 at the approximate center between adjacent water pipes 33 of the innermost circumferential annular water pipe row Pi. It is.
[0048]
That is, the innermost annular water pipe row Pi in which the plurality of water pipes 33 are evenly distributed in the circumferential direction, and the same number of cylindrical gas nozzles 2 as the water pipes 33 in the innermost peripheral annular water pipe row Pi are evenly distributed in the circumferential direction. When the upstream nozzle row Nu and the downstream nozzle row Nd are respectively viewed in the axial direction, the tips of the cylindrical gas nozzles 2 are positioned at the approximate center between the adjacent water pipes 33 in the innermost annular water pipe row Pi. The flame F formed by all the cylindrical gas nozzles 2 is configured to be cooled by the water pipe 33 under the same conditions.
[0049]
In the burner B of the third embodiment, each of the upstream nozzle row Nu and the downstream nozzle row Nd is divided into the same number (eight) as the number of installed cylindrical gas nozzles 2 in each row, as in the first embodiment. In this state, the flame F is formed, but since the combustion air A flows on both sides of the gas fuel jet flow ejected from each cylindrical gas nozzle 2 in the axial direction, the cylindrical gas nozzle 2 The gas fuel G ejected from is burned in a state in which the combustion air A is supplied from both sides and a bifurcated flame F is formed as viewed in the axial direction. The flames on both sides of the bifurcated flame F are formed so as to be inclined toward the circumferential side of the gas supply cylinder 1 with respect to the radial direction of the gas supply cylinder 1 as viewed in the axial direction. The
[0050]
Therefore, in the once-through boiler of the third embodiment, as in the first embodiment, the flame F is formed in each cylindrical gas nozzle 2 in a state where the flame forming direction is stable. The flame F formed in this manner can be stably cooled according to a predetermined condition by the water pipe 33 of the innermost circumferential annular water pipe row Pi. Therefore, it is possible to reduce both the amount of nitrogen oxides generated and the amount of carbon monoxide generated.
Further, in each of the upstream nozzle row Nu and the downstream nozzle row Nd, the flame F is caused by the cylindrical gas nozzles 2 between the adjacent water pipes 33 of the innermost circumferential annular water pipe row Pi as viewed in the axial direction. Since it is formed in a bifurcated shape at a position near the center of the heating chamber 32 in the approximate center, the flames on both sides of the bifurcated flame F are on the circumferential side of the gas supply cylinder 1 with respect to the radial direction of the gas supply cylinder 1 Therefore, when the combustion amount is small and the flame F is short, the flame F hardly hits the water pipe 33 of the innermost annular water pipe row Pi, and the cooling of the flame by the water pipe is suppressed. The larger the flame length becomes and the longer the flame F becomes, the easier it is for the flame F to hit the water pipe 33 in the innermost circumferential annular water pipe row Pi, and the flame F becomes easier to be cooled by the water pipe 33. Therefore, even if the length of the flame F changes with the change of the combustion amount, the flame F is cooled appropriately in order to reduce the generation amount of nitrogen oxide and the generation amount of carbon monoxide. Can do.
[0052]
[Fourth Embodiment]
Hereinafter, the fourth embodiment will be described.
In the fourth embodiment, the configuration of the annular water tube group P and the plurality of cylindrical gas nozzles 2 is the same as that of the third embodiment except that the arrangement is different from that of the third embodiment. A configuration different from the third embodiment will be described.
That is, as shown in FIG. 11, in the fourth embodiment, the annular water tube group P is divided into the innermost annular water tube row Pi, the intermediate annular water tube row Pm, and the outermost annular water tube row Po, as in the third embodiment. However, in each of the upstream nozzle row Nu and the downstream nozzle row Nd, the longitudinal direction of the cylindrical gas nozzle 2 is the radial direction of the gas supply cylinder 1 in the axial direction view. And the gas supply tube 1 is provided with its tip facing the water pipe 33 of the innermost annular water pipe row Pi.
[0053]
Therefore, in each of the upstream nozzle row Nu and the downstream nozzle row Nd, the flame F is formed in a forked shape at a position facing the water pipe 33 directly in front as viewed in the axial direction. Are formed in eight divisions.
Each flame F is formed in a bifurcated shape in which the water pipe 33 of the annular water pipe row Pi is positioned between the two branches when viewed in the axial direction in a state where the flame formation direction is stable. Therefore, the flame F is appropriately cooled by the water pipe 33 without being excessively cooled, and the flame F formed by all the cylindrical gas nozzles 2 is replaced with the water pipe of the innermost annular water pipe row Pi. By 33, it can cool stably according to the conditions defined to reduce the generation amount of nitrogen oxides and to reduce the generation amount of carbon monoxide. Therefore, it is possible to reduce both the amount of nitrogen oxides generated and the amount of carbon monoxide generated.
[0083]
[Another embodiment]
Next, another embodiment will be described.
(A) In each of the above embodiments, the number of the cylindrical gas nozzles 2 arranged at intervals in the circumferential direction of the gas supply cylinder 1 and the number of the water pipes 33 in the innermost circumferential annular water pipe row Pi are the same. Although illustrated, the number of the cylindrical gas nozzles 2 arranged at intervals in the circumferential direction of the gas supply tube 1 may be different from the number of the water tubes 33 in the innermost annular water tube row Pi.
For example, the number of the cylindrical gas nozzles 2 is half of the number of the water pipes 33 in the innermost circumferential annular water pipe row Pi, and the plurality of cylindrical gas nozzles 2 are arranged at the tips of the cylindrical gas nozzles 2 as viewed in the axial direction. However, you may provide in the state located in every other intermediate part among the intermediate parts of adjacent water pipes 33 of innermost circumference annular water pipe row Pi.
[0084]
(B) In each of the above first to fourth embodiments, the upstream nozzle row Nu and the downstream nozzle row Nd have different arrangement phases of the cylindrical gas nozzles 2 arranged in the circumferential direction of the gas supply cylinder 1. Also good.
For example, in the upstream nozzle row Nu, the tip of the cylindrical gas nozzle 2 is shifted in the circumferential direction of the gas supply cylinder 1 with respect to the water pipe 33 of the innermost annular water pipe row Pi in the axial direction view. In the state, the gas supply cylinder 1 is provided, and in the downstream nozzle row Nd, the cylindrical gas nozzle 2 is pointed directly in front of the water pipe 33 of the innermost annular water pipe row Pi as viewed in the axial direction. It is provided in the gas supply tube 1 in a state where
[0090]
(C) The arrangement form of the plurality of water pipes 33 in the annular water pipe group P is not limited to the arrangement form exemplified in each of the above embodiments.
  For example, a plurality of water pipes 33 may be arranged in a ring in a single row as viewed in the axial direction.
  Alternatively, when viewed in the axial direction, an innermost circumferential annular water pipe row Pi in which a plurality of water pipes 33 are arranged in an annular shape is formed at the innermost circumferential portion. 33 may be arranged irregularly without forming an annular row.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a once-through boiler according to a first embodiment.
FIG. 2 is a transverse bottom view of the once-through boiler according to the first embodiment.
3 is an arrow view of the burner of the once-through boiler in the direction of “ii” in FIG. 2;
FIG. 4 is a perspective view of the main part of the burner of the once-through boiler according to the first embodiment.
FIG. 5 is a transverse bottom view of a once-through boiler according to a second embodiment.
FIG. 6 is a longitudinal sectional view of a once-through boiler according to a third embodiment.
FIG. 7 is a transverse bottom view of the once-through boiler according to the third embodiment.
FIG. 8 is an arrow view of the burner of the once-through boiler in the roll direction of FIG.
FIG. 9 is a perspective view of the main part of the burner of the once-through boiler according to the third embodiment.
FIG. 10 is a partially cut bottom view of a burner of a once-through boiler according to a third embodiment.
FIG. 11 is a transverse bottom view of a once-through boiler according to a fourth embodiment.
FIG.Vertical section of a conventional once-through boiler
FIG. 13Vertical section of a conventional once-through boiler burner
[Explanation of symbols]
  1 Gas supply cylinder
  2 Cylindrical gas nozzle
  3 Air flow path
  3i Inner air flow path
  3o Outside air flow path
  11 Turning means
  12 Turning means
  13 Air discharge part
  16 Turning means
  17 Air discharge part
  32 Heating chamber
  33 Water pipe
  34 Combustion space
  A Combustion air
  B Burner
  G Gas fuel
  F flame
  Nd Downstream nozzle row
  Nu upstream nozzle row
  P ring water tube group
  Pi innermost ring water tube line
  T Air discharge means

Claims (5)

筒状の加熱室の内部に、加熱対象の水を通流させる複数の水管が夫々の長手方向を前記加熱室の軸心方向に沿わせる姿勢で、前記軸心方向に沿う軸心方向視にて環状に設けられ、
バーナが、前記加熱室における前記軸心方向一端側の中央部に配置されて、前記環状水管群の中央の空間を燃焼空間としてガス燃料を燃焼させるように構成された貫流ボイラであって、
前記バーナが、長手方向を前記軸心方向に沿わせて配置されるガス供給筒と、そのガス供給筒の先端側の周壁にその周壁から突出する状態で周方向に分散して設けられて、前記ガス供給筒内を流れるガス燃料を噴出する複数の筒状ガスノズルと、前記軸心方向視にて前記ガス供給筒の外周部に環状に設けられて、前記複数の筒状ガスノズルから噴出されるガス燃料に対して燃焼用空気を吐出する空気流路とを備えて構成され、
前記環状水管群と前記複数の筒状ガスノズルとが、全ての前記筒状ガスノズルにて形成される火炎が同一又は略同一の条件で前記水管により冷却される相対位置関係にて配設され、
前記空気流路が、内側空気流路と、その内側空気流路の外周部に位置し且つ出口が前記内側空気流路の出口よりも前記軸心方向の後端側に位置する外側空気流路とから構成され、
前記複数の筒状ガスノズルが、前記外側空気流路の出口から吐出される燃焼用空気に対してガス燃料を噴出するように周方向に分散して並ぶ上流側ノズル列と、その上流側ノズル列よりも前記軸心方向の先端側に位置して、前記内側空気流路の出口から吐出される燃焼用空気又は前記外側空気流路の出口から吐出される燃焼用空気に対してガス燃料を噴出するように周方向に分散して並ぶ下流側ノズル列とを形成するように、前記ガス供給筒に設けられ、
前記上流側ノズル列の各前記筒状ガスノズルが、軸心が前記ガス供給筒の軸心に直交し且つ前記軸心方向視にて長手方向が前記ガス供給筒の径方向に沿う姿勢となるように設けられ、
前記下流側ノズル列の前記筒状ガスノズルとして、軸心が前記ガス供給筒の軸心に直交し且つ前記軸心方向視にて長手方向が前記ガス供給筒の径方向に沿う姿勢の筒状ガスノズルと、軸心が前記ガス供給筒の軸心に直交する方向に対して前方に傾斜し且つ前記軸心方向視にて長手方向が前記ガス供給筒の径方向に沿う姿勢の筒状ガスノズルとが、前記ガス供給筒の周方向に交互に並ぶように設けられている貫流ボイラ。A plurality of water pipes that allow water to be heated to flow inside the cylindrical heating chamber in a posture in which each longitudinal direction is along the axial direction of the heating chamber, and viewed in the axial direction along the axial direction. Provided in a ring,
A once-through boiler configured to burn gas fuel using a central space of the annular water tube group as a combustion space, disposed at a central portion on one axial end side in the heating chamber in the heating chamber;
The burner is provided in a circumferentially distributed manner in a state of projecting from the peripheral wall on the peripheral wall on the front end side of the gas supply cylinder, the gas supply cylinder being arranged with the longitudinal direction along the axial direction, A plurality of cylindrical gas nozzles that eject gas fuel flowing in the gas supply cylinder, and an annular outer periphery of the gas supply cylinder as viewed in the axial direction, and are ejected from the plurality of cylindrical gas nozzles An air flow path for discharging combustion air to the gas fuel,
The annular water tube group and the plurality of cylindrical gas nozzles are arranged in a relative positional relationship in which flames formed by all the cylindrical gas nozzles are cooled by the water tube under the same or substantially the same conditions,
The air flow path is located on the inner air flow path and the outer periphery of the inner air flow path, and the outlet is located on the rear end side in the axial direction with respect to the outlet of the inner air flow path. And consists of
An upstream nozzle row in which the plurality of cylindrical gas nozzles are dispersed and arranged in the circumferential direction so as to eject gas fuel to the combustion air discharged from the outlet of the outer air flow path, and the upstream nozzle row Gas fuel is ejected from the combustion air discharged from the outlet of the inner air flow path or the combustion air discharged from the outlet of the outer air flow path, which is located on the tip end side in the axial direction. So as to form a downstream nozzle row distributed in the circumferential direction and arranged in the gas supply cylinder,
Each cylindrical gas nozzle of the upstream nozzle row has a posture in which the axial center is orthogonal to the axial center of the gas supply tube and the longitudinal direction is along the radial direction of the gas supply tube in the axial direction view. provided,
As the cylindrical gas nozzle of the downstream nozzle row, a cylindrical gas nozzle whose axis is perpendicular to the axis of the gas supply cylinder and whose longitudinal direction is along the radial direction of the gas supply cylinder in the axial direction view And a cylindrical gas nozzle whose axis is inclined forward with respect to a direction perpendicular to the axis of the gas supply cylinder and whose longitudinal direction is along the radial direction of the gas supply cylinder in the axial direction view. The once-through boiler is provided so as to be alternately arranged in the circumferential direction of the gas supply cylinder . 前記複数の筒状ガスノズルが、周方向に隣接するもの同士で分割状に火炎を形成するように、周方向に分散して設けられている請求項１記載の貫流ボイラ。2. The once-through boiler according to claim 1, wherein the plurality of cylindrical gas nozzles are provided so as to be dispersed in the circumferential direction so as to form a flame in a divided shape between those adjacent in the circumferential direction . 前記環状水管群における最内周側に、前記複数の筒状ガスノズルと同数の前記水管が環状に並ぶ最内周環状水管列が形成され、
前記筒状ガスノズルが、前記軸心方向視にて、その長手方向を前記ガス供給筒の径方向に沿わせ、且つ、その先端を前記最内周環状水管列の前記水管に対して前記周方向にずらした状態で前記ガス供給筒に設けられ、
前記軸心方向視にて、前記筒状ガスノズルから噴出されるガス燃料の燃焼により形成される火炎が、前記径方向に対して前記周方向側に傾く状態となるように、前記筒状ガスノズルから噴出されるガス燃料に対して、前記空気流路の出口から燃焼用空気を吐出させる空気吐出手段が設けられている請求項１又は２に記載の貫流ボイラ。On the innermost circumferential side of the annular water tube group, an innermost circumferential annular water tube row in which the same number of the water tubes as the plurality of cylindrical gas nozzles are annularly arranged is formed,
The cylindrical gas nozzle has its longitudinal direction along the radial direction of the gas supply cylinder, as viewed in the axial direction, and the tip thereof in the circumferential direction with respect to the water pipe of the innermost annular water pipe row Provided in the gas supply cylinder in a shifted state,
From the cylindrical gas nozzle, the flame formed by the combustion of the gas fuel ejected from the cylindrical gas nozzle is inclined toward the circumferential side with respect to the radial direction when viewed in the axial direction. The once-through boiler according to claim 1 or 2 , wherein an air discharge means for discharging combustion air from an outlet of the air flow path is provided for the jetted gas fuel . 前記外側空気流路の出口側に、前記空気吐出手段としての空気吐出部が、前記軸心方向視にて、周方向において、隣接する前記筒状ガスノズルの間に燃焼用空気を吐出するように設けられている請求項３記載の貫流ボイラ。An air discharge unit as the air discharge unit discharges combustion air between the adjacent cylindrical gas nozzles in the circumferential direction when viewed from the axial direction on the outlet side of the outer air flow path. The once- through boiler according to claim 3 provided. 前記空気流路の出口側に、前記空気吐出手段としての旋回手段が、前記空気流路を流れる燃焼用空気を旋回させて出口から吐出させるように設けられている請求項３記載の貫流ボイラ。4. The once- through boiler according to claim 3, wherein swirl means as the air discharge means is provided on the outlet side of the air flow path so as to swirl the combustion air flowing through the air flow path and discharge it from the outlet .
JP2001150633A 2001-05-21 2001-05-21 Once-through boiler Expired - Fee Related JP4674001B2 (en)

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JP2000055302A (en) * 1998-08-04 2000-02-22 Osaka Gas Co Ltd Boiler

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JP2000055319A (en) * 1998-08-04 2000-02-22 Osaka Gas Co Ltd LOW NOx BURNER
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