JPS6055724B2 - gas turbine combustor - Google Patents

Description

【発明の詳細な説明】 この発明はＮ０ｘの発生を低減させるようにしたガスタ
ービンの燃焼器に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas turbine combustor that reduces the generation of NOx.

ガスタービン燃焼器として、従来第１図に示すように、
燃料を予混合しながら希薄燃焼を行わせ低Ｎ０ｘ化をは
かつたものが知られている。Conventionally, as a gas turbine combustor, as shown in Fig. 1,
There are known fuels that perform lean combustion while premixing fuel to reduce NOx.

これは反応筒１に対して接線方向から開口するプレミキ
サ２を取付け、プレミキサ２の内部で燃料と空気を、理
論空燃比よりも希薄な状態に予混合し、この混合気にト
ーチ点火装置３で点火するようにしたもので、混合気に
旋回運動を附与する−ことで希薄燃焼を安定させている
。そしてこの高温の燃焼ガスは反応筒１を出た直後に希
釈空気と混合し、所定の温度まで冷却されてからタービ
ンに流入する。This involves installing a premixer 2 that opens tangentially to the reaction tube 1, premixing fuel and air inside the premixer 2 to a state leaner than the stoichiometric air-fuel ratio, and then using a torch ignition device 3 to mix the mixture. It is designed to ignite, imparting swirling motion to the air-fuel mixture, thereby stabilizing lean combustion. Immediately after leaving the reaction tube 1, this high-temperature combustion gas is mixed with dilution air, cooled to a predetermined temperature, and then flows into the turbine.

しかしながらこの燃焼器にあつては、あくまでもトーチ
によつて希薄混合気を着火させるという思想が基本であ
り、反応筒１に対して全ての燃料を噴射混合する容量の
大きなプレミキサ２が直接的に接続している、あるいは
反応筒１の燃焼域と希釈域が分離されていないことなど
から、エンジンが定常的に運転されているときはまだし
も、急゜加速や急減速をするときなどに安定した希薄燃
焼の維持が困難で、しかもタービンなどの負荷変動にも
とづく燃焼器下流のガス変動の影響が上流の燃焼域にも
及びやすく、燃焼安定性や排気組成を阻害するという問
題があつた。However, the basic idea of this combustor is to ignite a lean mixture using a torch, and a premixer 2 with a large capacity for injecting and mixing all the fuel is directly connected to the reaction tube 1. Because the combustion zone and dilution zone of reactor tube 1 are not separated, it is not possible to achieve stable dilution when the engine is operated steadily, but when there is sudden acceleration or deceleration. It is difficult to maintain combustion, and gas fluctuations downstream of the combustor due to load fluctuations in the turbine are likely to affect the upstream combustion region, impeding combustion stability and exhaust composition.

本発明はこのような問題に着目し、燃料と空気の混合を
多段階に分けて行い、濃混合気をもとにした改質ガスを
順次希薄化しつつ燃焼させることにより、常に安定した
希薄燃焼を実現するようにしたガスタービン燃焼器を提
供することを目的とする。The present invention has focused on these problems, and by dividing the mixing of fuel and air into multiple stages and combusting the reformed gas based on a rich mixture while gradually diluting it, the present invention achieves always stable lean combustion. An object of the present invention is to provide a gas turbine combustor that achieves the following.

以下、本発明の実施例を図面にもとづいて説明する。Embodiments of the present invention will be described below based on the drawings.

そのために本発明は、燃焼筒の内部に途中で絞つたスロ
ート部を境にして、上流に混合室、下流に燃焼室をそれ
ぞれ形成し、前記混合室に濃混合気を着火するトーチ点
火装置を取付けるとともに、混合室周囲に略均等間隔に
複数の連通管を接続し、かつ連通管を燃焼筒の軸線と略
平行に混合室外周に沿つて延長形成し、この延長端開口
部に燃料噴射弁を取付けて燃料改質管を構成し、これら
複数の燃料改質管で濃混合気を分解ガス化した改質ガス
を混合室からスロート部を経て燃焼室に噴出させる一方
、このスロート部下流の燃焼室に空気を導入して改質ガ
スを希薄燃焼させる空気孔を形成した。To this end, the present invention provides a torch ignition device that forms a mixing chamber upstream and a combustion chamber downstream of a throat portion that is narrowed midway inside the combustion tube, and ignites a rich air-fuel mixture in the mixing chamber. At the same time, a plurality of communication pipes are connected at approximately equal intervals around the mixing chamber, and the communication pipes are formed to extend along the outer periphery of the mixing chamber approximately parallel to the axis of the combustion cylinder, and the fuel injection valve is installed in the opening at the end of this extension. are installed to form a fuel reforming tube, and the reformed gas that has been decomposed and gasified from the rich mixture by these multiple fuel reforming tubes is injected from the mixing chamber into the combustion chamber via the throat section. Air holes were formed to introduce air into the combustion chamber and cause lean combustion of the reformed gas.

第２図において、燃焼筒１０の内部にはその中間部で絞
つたスロート部１１（直径比にして１１２〜１１４）を
境にして、その上流に混合室１２、下流に燃焼室１３が
形成される。In FIG. 2, inside the combustion tube 10, a mixing chamber 12 is formed upstream and a combustion chamber 13 is formed downstream of a throat portion 11 (diameter ratio: 112 to 114) that is narrowed in the middle. Ru.

混合室１２の軸線方向頂部にはトーチ点火装置１４が取
付けられ、このトーチ点火装置１４は燃料噴射ノズル１
５と空気導入孔１６及び点火栓１７とで構成され、混合
室１２の改質ガスと空気の混合体に着火する。A torch igniter 14 is attached to the top of the mixing chamber 12 in the axial direction, and this torch igniter 14 is connected to the fuel injection nozzle 1.
5, an air introduction hole 16, and a spark plug 17, which ignites the mixture of reformed gas and air in the mixing chamber 12.

混合室１２にはその周囲接線方向からほぼ均等間隔に開
口接続する複数の燃料改質管１８が取付けられる。A plurality of fuel reforming pipes 18 are attached to the mixing chamber 12 and are opened and connected at substantially equal intervals from the tangential direction of the circumference thereof.

この改質管１８は、一例として直径が２０〜４０７２の
連通管を基本として構成されており、燃焼筒１０の軸線
と略平行となるように折曲される一方、その他端にベル
マウス状入口部１９を有し、さらにその中心部に主燃料
ノズル２０を備えるとともにその周囲を空気口２１とし
た支持ボディ２２が入口部１９の内部に収められる。The reforming tube 18 is basically configured as a communicating tube with a diameter of 20 to 4072 mm, for example, and is bent so as to be approximately parallel to the axis of the combustion tube 10, and has a bellmouth-shaped inlet at the other end. A support body 22 having a main fuel nozzle 20 at its center and an air port 21 around the main fuel nozzle 20 is housed inside the inlet section 19 .

前記スロート部１１は燃焼室１３に向けてベンチユリ状
に拡大し、燃焼室１３にはこのスロート部１１の接続部
付近に複数の空気孔２３が形成さ．れるとともに、下流
の出口部２５の付近に複数の希釈空気孔２６が形成され
ている。The throat portion 11 expands in a bench lily shape toward the combustion chamber 13, and a plurality of air holes 23 are formed in the combustion chamber 13 near the connecting portion of the throat portion 11. At the same time, a plurality of dilution air holes 26 are formed near the downstream outlet section 25.

次に作用を説明する。Next, the action will be explained.

混合室１２の上流のトーチ点火装置１４は、エンジン作
動中に定常的に混合室軸心方向に噴出す！る燃焼トーチ
を形成しつづける。The torch igniter 14 upstream of the mixing chamber 12 constantly ejects light in the axial direction of the mixing chamber during engine operation! continues to form a burning torch.

そしてこれは燃費低減や排出ガス組成改善のため、エン
ジンコーステイングやアイドル状態のときに改質管１８
からの主燃料の供給が断たれても、火種として燃えつづ
け、再着火時にもトーチｔ火炎によつて安定的に着火を
行い、再着火時のＨＣの低減をはかるものである。In order to reduce fuel consumption and improve exhaust gas composition, the reformer pipe 18
Even if the main fuel supply from the torch is cut off, it will continue to burn as a spark, and even at the time of re-ignition, the torch t flame will stably ignite, thereby reducing HC at the time of re-ignition.

エンジンスタート時には、まずこのトーチ点火装置１４
が点火栓１７により噴射ノズル１５からの噴射燃料に着
火し、混合室１２に火炎を噴出する。When starting the engine, first use this torch ignition device 14.
The fuel injected from the injection nozzle 15 is ignited by the ignition plug 17, and a flame is ejected into the mixing chamber 12.

次いで、この混合室１２に開口している燃料改質管１８
の主燃料ノズル２０から燃料が噴射される。Next, a fuel reforming pipe 18 opening into this mixing chamber 12
Fuel is injected from the main fuel nozzle 20 of.

この燃料に対してはトーチ火炎が火種となつて改質管１
８の内部で空気口２１からの空気とともに、空燃比にし
て約８〜１２の過濃状態の燃焼を行わせる。The torch flame acts as a ignition source for this fuel, and the reformer tube 1
8 and the air from the air port 21 to perform combustion in a rich state with an air-fuel ratio of about 8 to 12.

この場合、各改質管１８は混合室１２の外周に沿つて管
長が十分にあり、しかも流量がそれほど多くないため、
入口部から供給された液体またはガス体の炭化水素系燃
料は、混合室１２からの燃焼熱を受けて鴇、ＣＯならび
に分解途中のＨＣからなる非常に燃えやすい可燃ガスに
十分に改質（分解）されつつ、ほぼ均一的な混合状態で
出口部へ流れる。In this case, each reforming pipe 18 has a sufficient pipe length along the outer periphery of the mixing chamber 12, and the flow rate is not so large.
The liquid or gaseous hydrocarbon fuel supplied from the inlet receives combustion heat from the mixing chamber 12 and is sufficiently reformed (decomposed) into a highly flammable combustible gas consisting of carbon dioxide, CO, and HC in the process of decomposition. ) while flowing to the outlet in a substantially uniformly mixed state.

この可燃性改質ガスは各改質管１８から混合室１２に略
接続方向から噴出し、ここで十分に混合しながら膨張し
、スロート部１１から燃焼室１３へ向けて整流、加速さ
れつつ流出する。This combustible reformed gas is ejected from each reforming pipe 18 into the mixing chamber 12 from approximately the direction of connection, expands while sufficiently mixing there, and flows out from the throat portion 11 toward the combustion chamber 13 while being rectified and accelerated. do.

以上が燃焼の第１段階であり、これらは理論空燃比から
外れた燃料過濃な状態で行われ、しかも混合室１２では
空燃比が全体的に均質でバラツキがなく、したがつてこ
の第１段目の燃焼ではＮＯｘの発生が極めて少なく、他
方、炭化水素燃料をより燃焼しやすいＨ２、ＣＯに分解
し、以後のこれらの燃焼を短時間のうちに完結しうる状
態にまで変化させる。The above is the first stage of combustion, and these are carried out in a fuel-rich state that deviates from the stoichiometric air-fuel ratio.Moreover, in the mixing chamber 12, the air-fuel ratio is homogeneous as a whole and there is no variation, so this first stage In the combustion of the second stage, very little NOx is generated, and on the other hand, the hydrocarbon fuel is decomposed into H2 and CO, which are more easily combustible, and the subsequent combustion of these is changed to a state that can be completed in a short period of time.

次に、スロート部１１で整流されたこの可燃ガスは、加
速噴流として燃焼室１３へと流入するが、流入と同時に
周囲の空気孔２３から導入された空気流と衝突混合する
。Next, this combustible gas that has been rectified by the throat portion 11 flows into the combustion chamber 13 as an accelerated jet, but at the same time as it flows in, it collides and mixes with the air flow introduced from the surrounding air holes 23.

空気孔２３は燃焼室１３の周囲からほぼ均一的にかつ中
心軸に対して４５〜９０らの角度をもつて下流に向けて
空気を流入させ、可燃ガスをすばやく燃焼させる。The air holes 23 allow air to flow substantially uniformly from the periphery of the combustion chamber 13 toward the downstream at an angle of 45 to 90 degrees with respect to the central axis, thereby quickly burning the combustible gas.

このときの燃焼室１３の中央部での空燃比は約２５〜４
０とし、理論空燃比１５付近の可燃ガスはもつとも噴流
速度の速い領域を短時間に通過するように設定する。At this time, the air-fuel ratio at the center of the combustion chamber 13 is approximately 25 to 4.
0, and the setting is made so that combustible gas with a stoichiometric air-fuel ratio of around 15 passes through a region where the jet velocity is high in a short time.

このようにしてすばやく希薄燃焼が行われた後、高温燃
焼ガスは下流の希釈空気孔２６から上流に向けて０〜６
０下の角度をもつて導入される空気により所定の温度ま
で均一的に冷却されてからタービンへと流入する。After quickly performing lean combustion in this way, the high-temperature combustion gas flows from the downstream dilution air hole 26 to the upstream direction.
The air introduced at an angle below zero is uniformly cooled to a predetermined temperature and then flows into the turbine.

この燃焼の第２段階では、ＮＯｘの生成率の高い理論空
燃比附近の可燃ガスを、高温度域を高速で通過させるこ
とにより滞留時間の短縮化をはかつているため、ＮＯｘ
の発生が十分に抑制されるし、またその下流の反応容積
の大きな燃焼室１３で改質管１８で生じたＨ２、ＣＯ等
、燃焼範囲が広くしかも燃焼速度の速い性質をもつたガ
ス成分を主体として希薄燃焼を行なうため、この主たる
燃焼は極めて安定した状態のもとで確実に完結し、未然
ＨＣ．．ＣＯとして排出ガス中に存在する割合は著しく
減少するのである。In this second stage of combustion, the combustible gas near the stoichiometric air-fuel ratio, which has a high NOx production rate, is passed through a high temperature range at high speed to shorten the residence time, so NOx
In addition, in the downstream combustion chamber 13 with a large reaction volume, gas components such as H2 and CO generated in the reforming tube 18, which have a wide combustion range and a high combustion rate, are suppressed. Since lean combustion is mainly performed, this main combustion is reliably completed under extremely stable conditions, and HC. ．． The proportion of CO present in the exhaust gas is significantly reduced.

次に、第３図に示すものは、改質管１８の主燃料ノズル
２０の周囲空気口２１に、導入空気に旋回運動を与える
スワラー２８を取付け、燃焼（改質化）の安定性を高め
た実施例である。Next, in the device shown in FIG. 3, a swirler 28 is attached to the peripheral air port 21 of the main fuel nozzle 20 of the reforming pipe 18 to give a swirling motion to the introduced air, thereby increasing the stability of combustion (reforming). This is an example.

同様な目的から、第４図のように、主燃料ノズル２０を
備える支持ボディ２２を環状段部２９から後退させ、燃
料と空気の混合をなお一層向上させることもできる。For a similar purpose, the support body 22 with the main fuel nozzle 20 can be set back from the annular step 29, as shown in FIG. 4, to further improve the mixing of fuel and air.

また、第５図の実施例は、燃焼室１３に燃焼制御板３０
を設け、スロート部１１からの噴流を円錐部３１に衝突
拡散させ、高速噴流となつた可燃ガスが燃焼室出口部２
５へと直接通り抜けるのを防止し、空気孔２３からの導
入空気と均質的に混合を行わせ、希薄燃焼のなお一層の
安定化をはかつたものである。Further, in the embodiment shown in FIG. 5, a combustion control plate 30 is provided in the combustion chamber 13.
is provided, the jet from the throat part 11 collides with the conical part 31 and diffuses, and the combustible gas that becomes a high-speed jet flows to the combustion chamber outlet part 2.
This prevents the air from passing directly through the air hole 23 and homogeneously mixes it with the air introduced from the air hole 23, thereby further stabilizing lean combustion.

この燃焼制御板３０は第６図ＡまたはＢに示すように形
成される。This combustion control plate 30 is formed as shown in FIG. 6A or B.

第６図Ａでは円錐部３１を複数のステー３２によつて支
持する構造であり、第６図Ｂは打抜穴３３を通して下流
へ可燃ガスを案内する構造を示す。6A shows a structure in which the conical portion 31 is supported by a plurality of stays 32, and FIG. 6B shows a structure in which combustible gas is guided downstream through punched holes 33.

以上説明したように本発明によれば、まず燃料過濃状態
で改質化を行い、この改質ガスをスロート部より噴射し
て希薄燃焼させるようにしたので、エンジンのあらゆる
運転条件下で、極めて安定した希薄燃焼が得られ、同時
にＮＯｘの抑制とＨＣ．ｓＣＯの大幅な低減がはかれる
。As explained above, according to the present invention, reforming is first performed in a rich fuel state, and the reformed gas is injected from the throat section to perform lean combustion, so that under all operating conditions of the engine, Extremely stable lean combustion can be obtained, and at the same time, NOx suppression and HC. A significant reduction in sCO is achieved.

燃焼筒は混合室と燃焼室を分離した構造をもつため、燃
焼室下流のガス状態の変動が燃焼に及ぼす影響が少なく
、常に良好かつ応答性にすぐれた燃焼状態が確保できる
。Since the combustion tube has a structure in which the mixing chamber and the combustion chamber are separated, fluctuations in the gas state downstream of the combustion chamber have little effect on combustion, and a good and responsive combustion state can always be ensured.

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

第１図Ａ，Ｂは従来装置の横断面図及び縦断面図、第２
図は本発明の縦断面図、第３図、第４図は改質管の要部
断面図、第５図は燃焼室の要部断面図、第６図Ａ，Ｂは
そのＩ−１線矢示図である。 １０・・・・・・燃焼筒、１１・・・・・・スロート部
、１２・・・．・・・混合室、１３・・・・・・燃焼室
、１４・・・・・・トーチ点火装置、１８・・・・・・
燃料改質管。Figures 1A and B are a cross-sectional view and a longitudinal sectional view of the conventional device, and Figure 2
The figure is a longitudinal cross-sectional view of the present invention, Figures 3 and 4 are cross-sectional views of the main parts of the reforming tube, Figure 5 is cross-sectional views of the main parts of the combustion chamber, and Figures 6 A and B are the I-1 line. It is an arrow diagram. 10... Combustion cylinder, 11... Throat part, 12... ...Mixing chamber, 13... Combustion chamber, 14... Torch ignition device, 18...
Fuel reformer tube.

Claims (1)

【特許請求の範囲】[Claims] １ 燃焼筒の内部に途中で絞つたスロート部を境にして
、上流に混合室、下流に燃焼室をそれぞれ形成し、前記
混合室に濃混合気を着火するトーチ点火装置を取付ける
とともに、混合室周囲に略均等間隔に複数の連通管を接
続し、かつ連通管を燃焼筒の軸線と略平行に混合室外周
に沿つて延長形成し、この延長端開口部に燃料噴射弁を
取付けて燃料改質管を構成し、これら複数の燃料改質管
で濃混合気を分解ガス化した改質ガスを混合室からスロ
ート部を経て燃焼室に噴出させる一方、このスロート部
下流の燃焼室に空気を導入して改質ガスを希薄燃焼させ
る空気孔を形成したことを特徴とするガスタービン燃焼
器。1 Inside the combustion tube, a mixing chamber is formed upstream and a combustion chamber downstream, with the throat section narrowed halfway as a boundary, and a torch ignition device for igniting a rich mixture is installed in the mixing chamber, and the mixing chamber A plurality of communication pipes are connected at approximately equal intervals around the periphery, and the communication pipes are formed to extend along the outer periphery of the mixing chamber approximately parallel to the axis of the combustion cylinder, and a fuel injection valve is attached to the opening at the extension end to perform fuel reformation. These multiple fuel reforming tubes decompose and gasify the rich mixture and inject the reformed gas from the mixing chamber into the combustion chamber via the throat section, while also injecting air into the combustion chamber downstream of this throat section. A gas turbine combustor characterized in that an air hole is formed to introduce and burn reformed gas in a lean manner.