JP3845875B2 - Gas turbine compressor and gas turbine - Google Patents

Description

【００５７】
【表２】

【００５８】
表３はこれらロータ材の機械的性質を示す。室温引張試験，Ｖノッチシャルピー衝撃試験及びクリープ破断試験は、ＪＩＳ試験法に従って行った。衝撃試験は、高温長時間脆化を模擬した下記に示す。図３に示すステップクール脆化処理後に実施した。
【００５９】
【表３】

【００６０】
クリープ破断強度は、ラルソン−ミラー法で求めた。最も高温部に用いられるロータ材として要求される機械的性質（室温引張強さ≧８５kg／mm² ，破面遷移温度≦２０℃，５３８℃，１０⁵ｈ クリープ破断強度≧３０kg／mm² ）と本供試鋼の性質を見るとＮo.１は破面遷移温度が高く、低温靭性不足であるが、室温引張強さとクリープ破断強度を満足するので、比較的高温部のロータｅに適用される。Ｎo.２はクリープ破断強度が低く、高温強度不足であるが室温引張強さと破面遷移温度を満足するので、温度の低い上流側のロータａ〜ｄに適用される。
【００６１】
これに対し、Ｎo.３及びＮo.４は、室温引張強さ，破面遷移温度及びクリープ破断強度共に十分満足し、圧縮機のｅ及びｆのロータ材の高温部に対して極めて有用であるといえる。全体をこの材料によって構成することができる。全体を同じ材料で構成することは管理，製造の点から有利である。
【００６２】
図１は本発明の６分割型ロータよりなるガスタービン用圧縮機を有するガスタービンの回転部分の部分断面図である。
【００６３】
１０はタービンスタブシャフト、３はタービンブレード、１１はタービンスタッキングボルト、８はタービンスペーサ、１４はディスタントピース、２はタービンノズル、６は圧縮機用分割ロータ、７はコンプレッサブレード、９はコンプレッサスタブシャフトの軸受部、４はタービンディスク、１１は穴である。本発明のガスタービンはコンプレッサブレード７が１７段あり、又タービンブレード３が３段のものである。
【００６４】
本実施例におけるガスタービンは、主な形式がヘビーデューティ形，一軸形，水平分割ケーシング，スタッキング式ロータからなり、圧縮機が１７段軸流形，タービンが３段インパルス形，１，２段空気冷却による静動翼，燃焼器がバースフロー形，１６缶，スロットクール方式を有するものである。
【００６５】
図１において、分割ロータａには１及び２段翼を、ｂには３及び４段翼を、ｃには５及び６段翼をｄには７および８段翼を、ｅには９，１０および１１段翼を、ｆには１２〜１４段翼を植込む構造になっており、ボルト１９によって一体に結合される。各ロータは２段目のブレードと最終段のブレードの植込み間でボルト１９によって結合される。ロータｆはディスタントピース１４及び１４′とボルトによって一体化している。ディスタントピース１４′には１５〜１７段翼を植込む構造を有する。これらのいずれのボルトも耐熱鋼よりなり全周で１０本以上が用いられる。ロータａ〜ｅは３５０℃以下で使用されるので、高温強度（クリープ破断強度）は要求されないが、高い低温靭性が要求される。特にロータａには軸受部分が設けられるとともに長翼が植込まれるので最も高い遠心応力を受ける上に、最も低温（３５℃）で使用される。その為に、ロータａには最も高い低温靭性が要求される。一方、ロータｆは最も高温（≦４００℃）に曝されるので、高いクリープ破断強度と優れた耐酸化特性が要求される。
【００６６】
ロータａ〜ｄはいずれも各ロータに２段の図３のブレードがロータ軸の軸方向に添って斜めに設けられた溝に植込まれ、ロータｅ及びｆは３段のブレードが植込まれ、両サイドには図３のブレードが植込まれ、中央部はロータ中心の円周上に設けられた溝に図２のブレードが植込まれる。ロータｆの下流側にはディタントピース１２が設けられ、３段のブレードが植込まれ、両サイドが図３のブレードが前述のロータａ〜ｄと同様に植込まれ、中央部には図２のブレードが前述と同様に円周上に設けられた溝に植込まれる。ロータａ〜ｃはいずれも直径が同一であり、ロータｄ及びｅの直径はロータｃとｆとの直径に合せて徐々に大きくなっており、ロータｆの直径は最大となる。本実施例におけるブレード植込み間の全長はロータ直径の最大に対し３.４〜３.８倍又は最小径に対して４.０〜４.４倍の長さを有している。ロータ間の中心部には軽量とするため空間となる。ロータｆ及びディタントピース１４に植込まれるブレードの長さは同じとし、他は初段から下流側に対して徐々にブレードの長さを短くしている。ブレードの長さは最終段に対して初段の長さを３.４５ 倍とし、好ましくは３〜４倍とする。ロータｂ〜ｆはディスク型であり、ｄ〜ｆはブレードの植込み部直下に軽量とするリング状の空間が設けられる。各ロータ間の中心部は空洞になっており軽量化される。
【００６７】
ブレード間の間隔は初段から８段目までは徐々に減少し、８〜１０段の３段は同じ間隔とし、更に１１段〜１７段目も同じ間隔とし、８〜１０段より更に小さい間隔となる。初段と２段目とのブレード間隔は最終段とその手前との間隔の約２.７〜３.２倍であり、初段のブレード長さは最終段の長さより約３.５〜４.２倍とする。
【００６８】
表４に示す材料についてガスタービン用各種部材として実物相当の大形鋼を、エレクトロスラグ再溶解法により溶製し、鍛造・熱処理を行った。鍛造は８５０〜１１５０℃の温度範囲内で、熱処理は表６に示す条件で行った。表６には化学組成（重量％）を示す。これら材料の顕微鏡組織は、Ｎo.５〜８が全焼戻しマルテンサイト組織、Ｎo.９が全焼戻しベーナイト組織であった。Ｎo.５はディスタントピース及び最終段のコンプレッサディスクに使用し、前者は厚さ６０mm×幅５００mm×長さ１０００mm、後者は直径１０００mm，厚さ１８０mm，Ｎo.２１はディスクとして直径１０００mm×厚さ１８０mmに、Ｎo.７はスペーサとして外径１０００mm×内径４００mm×厚さ１００mmに、Ｎo.８はタービンスタッキングボルトとして直径４０mm×長さ５００mmを用い同様にディスタントピースとタービンディスクとを結合するボルトも製造した。Ｎo.９はタービンスタブシャフトとして直径２５０mm×長さ３００mmに鍛伸した。試験片は熱処理後、試料の中心部分から、Ｎo.８を除き、軸（長手）方向に対して直角方向に採取した。この例は長手方向に試験片を採取した。
【００６９】
【表４】

【００７０】
表５はその室温引張、２０℃Ｖノッチシャルピー衝撃およびクリープ破断試験結果を示すものである。４５０℃×１０⁵ｈ クリープ破断強度は一般に用いられているラルソン−ミラー法によって求めた。
【００７１】
本発明のＮo.５〜８（１２％Ｃｒ鋼）を見ると、４５０℃，１０⁵ｈ クリープ破断強度が５０kg／mm² 以上、２０℃Ｖノッチシャルピーが７kg−ｍ／cm² 以上であり、高温ガスタービン用材料として必要な強度を十分満足することが確認された。
【００７２】
【表５】

【００７３】
次にスタブシャフトのＮo.９（低合金鋼）は、４５０℃クリープ破断強度は低いが、引張強さが８６kg／mm² 以上、２０℃Ｖノッチシャルピー衝撃値が７kg−ｍ／cm²以上であり、スタブシャフトとして必要な強度（引張強さ≧８１kg／mm²，２０℃Ｖノッチシャルピー衝撃値≧５kg−ｍ／cm² ）を十分満足することが確認された。
【００７４】
このような条件におけるディスタントピースの温度及び最終段のコンプレッサロータシャフト部分の温度は最高４５０℃となる。前者の肉厚は２５〜３０mm好ましい。タービンディスクは中心に貫通孔が設けられる。タービンディスクには貫通孔に圧縮残留応力が形成される。
【００７５】
タービンディスク１０は３段であり、ガス上流側の初段及び２段目には中心孔１１が設けられている。本実施例においてはいずれも表８に示す合金によってタービンブレード３，タービンノズル１４，燃焼器５のライナ１３，コンプレッサブレード７，コンプレッサノズル１２，ダイヤフラム１５及びシュラウド１を構成した。特に、タービンノズル２及びタービンブレード３は鋳物によって構成される。タービンノズルの初段にはＮｉ基合金および２段と３段にはＣｏ基合金を用いた。
【００７６】
表６のシュラウドセグメント（１）はガス上流側の１段目に使用したもので、（２）は２段及び３段目に使用したものである。
【００７７】
【表６】

【００７８】
燃焼器ライナ１３，動翼３及び静翼２には外表面の火炭にさらされる高温部にＹ₂Ｏ₃安定化ジルコニア溶射層（又はＣＶＤコーテング）の遮熱コーテング層が火炎に接する部分に設けられる。特に、ベース金属とコーテング層との間に重量でＡｌ２〜５％，Ｃｒ２０〜３０％，Ｙ０.１ 〜１％を含む残部Ｎｉ又はＮｉ＋Ｃｏからなる合金層が設けられる。
【００７９】
図２及び図３は本発明の分割ロータ型圧縮機用ブレードの形状を示す斜視図である。
【００８０】
ガスタービン用一体ロータ型圧縮機の場合には、ブレードのフック長さＬを、Ｌ≦Ｐ／２（ここでＰ：ブレードのピッチ）にすることにより、ブレードの植設が可能になる。ブレードは翼部１６，プラットフォーム部１７及び植込み部１８を有し、プラットフォーム部１７には植込部側に突起１９が設けられる。
【００８１】
大型圧縮機の場合、空気入口側はブレードが長くなるので、高い遠心力を受けるため、比強度の高い材料が必要である。一方、空気出口側のブレードは高温に曝されるので、クリープ強度の高い材料が必要である。
【００８２】
本実施例では、表７に示す初段から５段までを比重が低く、引張強さの高い Ｎo.１１のＴｉ−６Ａｌ−４Ｖ合金を、６段から１７段までを高温強度の高い、Ｎo.１０の１２Ｃｒ耐熱鋼を使用した。
【００８３】
【表７】

【００８４】
Ｔｉ−６Ａｌ−４Ｖ合金ブレードは熱間鍛造後、７０５℃焼鈍を行った。
【００８５】
１２Ｃｒ耐熱鋼ブレードは溶解・熱間鍛造後、１１００℃油焼入れ及び６５０℃焼もどしを行った。
【００８６】
表８は圧縮機用ブレードの機械的性質を示す。
【００８７】
空気入口側に比強度の高いＴｉ合金を、空気出口側にクリープ強度の高い12Cr耐熱鋼を使用することにより、信頼性の高い圧縮機ができる。
【００８８】
【表８】

【００８９】
本実施例におけるノズルにはSUS410又はＭｏ入りのSUS410J1が用いられる。
【００９０】
本実施例ではブレードはロータ６の円周面に軸方向に斜めの軸を形成する場合（図３）と、ブレードの段の数の前記ブレード７の植込み部断面形状のリング状の溝を形成し、リング状の溝の中で１ケ所だけ植込み部が入る大きさの穴に溝を設け、その部分よりブレードを植込む場合（図２）とがある。後者は更に最初と最後のブレードは植込部がこの穴より抜けないように調整される。各ブレードは互いにプラットフォームで接して固定される。ブレードの突起部１９はロータシャフト内部に植込まれ、プラットフォーム部はロータシャフト面と同じ面となるようにしている。後者はロータのｅ及びｆの中央部に相当する部分で形成され、他は前者の溝形成によってブレードが植込まれる。
【００９１】
以上の構成によって、圧縮比１５〜１８，温度４００〜５００℃，圧縮効率 ８６％以上，初段タービンノズル入口のガス温度３６０℃以上，排気温度５３０℃以上が可能になり、３５％以上の熱効率が得られるとともに、タービンディスク，ディスタントピース，スペーサ，コンプレッサロータシャフト，スタッキングボルトを前述の如く高いクリープ破断強度及び加熱脆化の少ない耐熱鋼が使用されるとともに、タービンブレードにおいても高温強度が高く、タービンノズルは高温強度及び高温延性が高く、燃焼器ライナは同様に高温強度及び耐疲労強度が高い合金が使用されているので、総合的により信頼性が高くバランスされたガスタービンが得られるものである。使用燃料として、天然ガス，軽油が使用される。
【００９２】
ガスタービンにはインタークーラーがあるものがほとんどあるが、本発明はインタークーラーのない場合ノズルがより高温になるので、それに特に好適である。本実施例でのタービン用ノズルは全周で初段で４０ケ前後設けられる。
【００９３】
実施例２
次に、分割型ロータをエレクトロスラグ再溶解法（以下ＥＳＲ法と略称する）により、２種類の電極を用い作製した。
【００９４】
空気入口側のロータａ〜ｃには低温靭性の高い材料を、空気出口側のロータｄ〜ｆ及びディスタントピース１４′には高温強度の高い材料を使用した。これらの鋼塊を熱間鍛造後、熱処理を施した。
【００９５】
表９は圧縮機ＥＳＲロータ材の化学組成（重量％）、表１０は熱処理条件、表１１は圧縮機ＥＳＲロータ材の機械的性質を示す。
【００９６】
本圧縮機ＥＳＲロータは、空気入口側で要求される低温靭性と空気出口側で要求される高温強度が著しく高く、信頼性が非常に優れている。
【００９７】
【表９】

【００９８】
【表１０】

【００９９】
【表１１】

【０１００】
空気入口側には引張強さ８０kg／mm²以上，Ｖノッチ衝撃値が１５kg−ｍ／cm²以上，ＦＡＴＴ０℃以下の高靭性、空気出口側には引張強さ８０kg／mm²以上，１５０℃，１０⁵ｈクリープ破断強度を３５kg／mm² 以上、好ましくは４０kg／ mm² 以上のものが得られる。
【０１０１】
本実施例におけるブレード及びノズルは実施例１と同じである。
【０１０２】
実施例３
図５は実施例１又は２のガスタービンを用い、蒸気タービンと併用した一軸コンバインドサイクル発電システムを示す概略図である。これらのガスタービンと蒸気タービンは複数台組合わせて発電することができ、各々３台又は６台ずつ組合わせることができる。
【０１０３】
ガスタービンを利用して発電を行う場合、近年では液化天然ガス（ＬＮＧ）を燃料としてガスタービンを駆動するとともにガスタービンの排ガスエネルギーを回収して得た水蒸気で蒸気タービンを駆動し、この蒸気タービンとガスタービンとで発電機を駆動するようにした、いわゆる複合発電方式を採用する傾向にある。この複合発電方式を採用すると、従来の蒸気タービン単独の場合の熱効率４０％に比べ４６％以上と熱効率を大幅に向上させることが可能となる。
【０１０４】
このような複合発電プラントにおいて、最近ではさらに、液化天然ガス(LNG）専焼から液化石油ガス（ＬＰＧ）との両用を図ったり、ＬＮＧ，ＬＰＣの混焼の実現によって、プラント運用の円滑化，経済性の向上化を図ろうとするものである。
【０１０５】
まず空気は吸気フィルタと吸気サイレンを通ってガスタービンの空気圧縮機に入り空気圧縮機は、空気を圧縮し圧縮空気を低ＮＯｘ燃焼器へ送る。
【０１０６】
そして、燃焼器では、この圧縮空気の中に燃料が噴射され燃焼して１４００℃以上の高温ガスを作りこの高温ガスは、ガスタービンで仕事をし動力が発生する。
【０１０７】
ガスタービンから排出された５５０℃以上の燃焼排ガスは、排気消音装置を通って排熱回収ボイラへ送られ、熱エネルギーを回収して５３０℃以上の高圧水蒸気及び低圧蒸気が各々低圧蒸気管及び高圧主蒸気管より蒸気タービンに送られる。このボイラには乾式アンモニア接触還元による脱硝装置が設けられている。排ガスは３脚集合型の数百ｍもある煙突から外部に排出される。
【０１０８】
発生した高圧および低圧の蒸気は高低圧一体ロータからなる蒸気タービンに送られる。蒸気タービンは以後に示される。
【０１０９】
また、蒸気タービンを出た蒸気は、復水器に流入し、真空脱気された復水になり、復水は、復水ポンプで昇圧され給水となって再びボイラへ送られる。そして、ガスタービンと蒸気タービンは夫々、発電機をその両軸端から駆動して、発電が行われる。このような複合発電に用いられるガスタービン翼に冷却には、冷却媒体として蒸気タービンで利用される蒸気を用いることもある。一般には翼の冷却媒体としては空気が用いられているが、蒸気は空気と比較して比熱が格段に大きく、また重量が軽いため冷却効果は大きい。比熱が大きいために冷却に利用された蒸気を主流ガス中に放出すると主流ガスの温度低下がはげしくプラント全体の効率を低下させるので蒸気タービン内の比較的低温(例えば約８００℃程度)の蒸気をガスタービン翼の冷却媒体供給口から供給し、翼本体を冷却，熱交換して比較的高温（例えば約９００℃程度）になった冷却媒体を回収して蒸気タービンに戻すように構成して、主流ガス温度（約１３００℃〜１５５０℃程度）の低下を防止すると共に蒸気タービンの効率向上、ひいてはプラント全体の効率を向上させることができる。このコンバインド発電システムによりガスタービンが約６万ｋＷ，蒸気タービンにより３万ｋＷのトータルで９万ｋＷの発電を得ることができ、本実施例における蒸気タービンはコンパクトとなるので、大型蒸気タービンに比べ同じ発電容量に対し経済的に製造可能となり、発電量の変動に対して経済的に運転できる大きなメリットが得られる。
【０１１０】
ガスタービンは前述の実施例１又は２に記載のいずれのものも適用でき、コンプレッサによって圧縮された空気が燃焼器に送られ、燃焼ガス温度１４００℃以上の高い温度に燃焼され、その燃焼ガスをブレードを植設されたディスクを回転させるものである。
【０１１１】
図６に本発明に係る再熱型高低圧一体型蒸気タービンの部分断面図を示す。この高低圧一体型蒸気タービンの主蒸気入口部の蒸気圧力１００atg 以上，温度 ５３０℃以上に上昇させることによりタービンの単機出力の増加を図ることができる。単機出力の増加は、最終段動翼の翼長を増大し、蒸気流量を増す必要がある。例えば、最終段動翼の翼長を２６インチから３３.５ インチ長翼にすると環帯面積が１.７ 倍程度増える。したがって、従来出力１００ＭＷから１７００ ＭＷに、さらに４０インチまで翼長を長くすれば、単機出力を２倍以上に増大することができる。
【０１１２】
この３３.５ インチ以上の長さのものに対するロータシャフト材として、0.5 ％Ｎｉを含むＣｒ−Ｍｏ−Ｖ鋼を高低圧一体ロータに使用した場合、本ロータ材は、もともと高温部域に使用するため、高温強度，クリープ特性に優れているため、主蒸気入口部の蒸気圧力，温度の上昇に対しては充分対応することが出来る。低温部域、特に最終段動翼部のタービンロータ中心孔に、定格回転状態にて生ずる接線方向応力は、２６インチ長翼の場合、応力比（作用応力／許容応力）で約０.９５ であり、また３３.５ インチ長翼の場合では約１.１ となり、使用に耐えない。
【０１１３】
一方、３.５％ Ｎｉ−Ｃｒ−Ｍｏ−Ｖ鋼を使用した場合には、本ロータ材は低温域にて靭性を有する材料であると共に、Ｃｒ−Ｍｏ−Ｖ鋼よりも低温度域での抗張力，耐力が１４％程度高いことから、３３.５ インチ長翼を使用しても、前記する応力比は約０.９６ である。また４０インチ長翼を使用した場合、前記の応力比は１.０７ となり使用に耐えない。高温度域に於いては、クリープ破断応力がＣｒ−Ｍｏ−Ｖ鋼の０.３ 倍程度であることが高温強度不足となり使用に耐えない。
【０１１４】
この様に高出力化を図るためには、高温度域ではＣｒ−Ｍｏ−Ｖ鋼，低温度域ではＮｉ−Ｃｒ−Ｍｏ−Ｖ鋼の優れた特性を兼ね備えたロータ材が必要である。３０インチ以上４０インチクラスの長翼を使用する場合、前記の如く応力比が１.０７ となるために、引張強さ８８kg／mm² 以上の材料が必要である。さらに、３０インチ以上の長翼を取付ける高低圧一体型蒸気タービンロータ材としては、高圧側の高温破壊に対する安定性確保の点から５３８℃，１０⁵ｈ クリープ破断強度１５kg／mm² 以上、低圧側の脱性破壊に対する安全性確保の点から室温の衝撃吸収エネルギー２.５kg−ｍ（３kg−ｍ／cm²）以上の材料が必要である。
【０１１５】
本発明に係る蒸気タービンは高低圧一体型ロータシャフト２３に植設されたブレード２４を１５段備えており、蒸気は蒸気コントロールバルブ２５を通って蒸気入口３４より５３８℃，１２６atg の高温高圧の蒸気が高圧部３０に流入する。蒸気は高圧部３０に流入し、３６７℃，３８atg となって出る。その蒸気は更に排熱回収ボイラの再熱器３３によって再熱されて５３８℃，３５atg に加熱されてロータの低圧部３１を通り、約４６℃，０.１atgの蒸気として出口２２より排出され、復水器に入る。３２は軸受である。
【０１１６】
本実施例に係る高低圧−型体ロータシャフト２３は５３８℃蒸気から４６℃の温度までさらされるので、ＦＡＴＴ６０℃以下，５３８℃，１０⁵ｈ 強度が１１kg／mm² 以上の特性のＮｉ−Ｃｒ−Ｍｏ−Ｖ低合金鋼の鍛鋼が用いられる。ロータシャフト２３のブレード２４の植込み部はディスク状になっており、ロータシャフト２３より一体に切削されて製造される。ディスク部の長さはブレードの長さが短いほど長くなり、振動を少なくすることになっている。
【０１１７】
本発明に係るロータシャフト２３は前述の表４に示す合金組成の鋼をエレクトロスラグ再溶解によってインゴットを製造するとともに、直径１.２ｍ に熱間鍛造し、９５０℃，１０時間加熱保持した後、中心部で１００℃／ｈとなるようにシャフトを回転しながら水噴霧冷却を行った。次いで６６５℃で４０時間加熱保持の焼戻しを行った。このロータシャフト中心部より試験片を切り出しクリープ破断試験，加熱前後（５００℃，３０００時間加熱後）のＶノッチ衝撃試験（試験片の断面積０.８cm²），引張試験を行った。
【０１１８】
(1）高低圧−体型ロータシャフト
本実施例ではこの部材として前述した圧縮機用ロータシャフト材と同じ組成及び組織を有するＮｉ−Ｃｒ−Ｍｏ−Ｖ系低合金鋼を用いることができる。特に、（Ｍｎ／Ｎｉ）比が０.１２以下又は（Ｓｉ＋Ｍｎ）／Ｎｉ比を０.１８以下が好ましく、また（Ｖ＋Ｍｏ）／（Ｎｉ＋Ｃｒ）比が０.４５〜０.７０とするものが好ましい。更に、この低合金鋼に更に希土類元素，Ｍｇ，Ｃａ０.０４％ 以下，Ｈｆ，Ｚｒ０.２％ 以下，Ｗ１％以下の１種以上を含有させることができる。
【０１１９】
(2）ブレード（圧縮機，蒸気タービン）
圧縮機の出口側の３段，蒸気タービンの高温高圧側の３段の長さが約４０mmで、材料として重量でＣ０.２０〜０.３０％，Ｃｒ１０〜１３％，Ｍｏ０.５〜1.5％，Ｗ０.５〜１.５％，Ｖ０.１〜０.３％，Ｓｉ０.５％ 以下、Ｍｎ１％以下及び残部Ｆｅからなるマルテンサイト鋼の鍛鋼で構成した。
【０１２０】
蒸気タービンの中圧部は低圧側になるに従って徐々に長さが大きくなり、重量でＣ０.０５〜０.１５％，Ｍｎ１％以下，Ｓｉ０.５％以下，Ｃｒ１０〜１３％,Ｍｏ０.５％以下，Ｎｉ０.５％以下，残部Ｆｅからなるマルテンサイト鋼の鍛造で構成した。
【０１２１】
圧縮機の初段又は蒸気タービンの最終段として、長さ３３.５ インチでは、一周で約９０本あり、材料として重量でＣ０.０８〜０.１５％，Ｍｎ１％以下， Ｓｉ０.５％以下，Ｃｒ１０〜１３％，Ｎｉ１.５〜３.５ ％，Ｍｏ１〜２％，Ｖ０.２〜０.５％，Ｎ０.０２〜０.０８％，残部Ｆｅからなるマルテンサイト鋼の鍛造によって構成した。また、この最終段にはステライト板からなるエロージョン防止のシールド板が溶接によってその先端で、リーデングエッジ部に設けられる。またシールド板以外に部分的な焼入れ処理が施される。更に、圧縮機の初段又は蒸気タービンの最終段の４０インチ以上の長いものにはＡｌ５〜８％，Ｖ３〜６％を含むＴｉ翼が用いられる。
【０１２２】
これらの蒸気タービンブレードは各段で４〜５枚をその先端に設けられた突起テノンのかしめによる同材質からなるシュラウド板によって固定される。
【０１２３】
３０００rpm では４０インチの長さでも上述の１２％Ｃｒ鋼が用いられ、3600rpm では４０インチではＴｉ翼となるが３３.５ インチまで１２％Ｃｒ鋼が用いられる。
【０１２４】
(3）圧縮機におけるノズルには１３％Ｃｒフェライト系のＳＵＳ材が用いられ、蒸気タービンの静翼２７には、高圧の３段までは動翼と同じ組成のマルテンサイト鋼が用いられるが、他には前述の中圧部の動翼材と同じものが用いられる。
【０１２５】
(4）蒸気タービンケーシング２６には、重量でＣ０.１５〜０.３ ％，Ｓｉ０.５％以下、Ｍｎ１％以下、Ｃｒ１〜２％，Ｍｏ０.５〜１.５％，Ｖ０.０５〜０.２％，Ｔｉ０.１ ％以下のＣｒ−Ｍｏ−Ｖ鋳鋼が用いられる。２８は発電機であり、この発電機により１０〜２０万ｋＷの発電ができる。本実施例におけるロータシャフトの軸受３２の間は約５２０cm、最終段ブレードにおける外径３１６cmであり、この外径に対する軸間比が１.６５ である。発電容量として１０万ｋＷが可能である。この軸受間の長さは発電出力１万ｋＷ当り０.５２ｍ である。
【０１２６】
また、本実施例において、最終段ブレードとして４０インチを用いた場合の外径は３６５cmとなり、この外径に対する軸受間比が１.４３ となる。これにより発電出力２０万ｋＷが可能であり、１万ｋＷ当りの軸受間距離が０.２６ｍ となる。
【０１２７】
これらの最終段ブレードの長さに対するロータシャフトのブレード植込み部の外径との比は３３.５″ ブレードでは１.７０及び４０″ブレードでは１.７１である。
【０１２８】
本実施例では蒸気温度を５６６℃としても適用でき、その圧力を１２１，169 及び２２４atg の各々の圧力でも適用できる。
【０１２９】
プラントの構成は、ガスタービン，排熱回収ボイラ，蒸気タービン，発電機各１基からなる１組の発電システムを６組組み合わせて１軸形としたが、複数台のガスタービンと各々の排熱回収ボイラとを組合わせ、これによって得られる蒸気を用いて１台の蒸気タービンによって発電する多軸形コンバインドサイクルにも適用できる。
【０１３０】
発電出力の割合は、一軸の場合はガスタービンが２／３，蒸気タービンが１／３として分担される。また、ガスタービンの出力として５万ｋＷ〜２０万ｋＷとすることができ、蒸気タービンはこれに合わせて上述の出力のものを用いる。
【０１３１】
従来の火力発電に比べ熱効率が２〜３％高くなります。また、部分負荷でもガスタービンの運転台数を減らすことにより、運転中の設備を熱効率の高い定格負荷付近で運転することが出来るため、プラント全体として４６％以上の高い熱効率が維持出来た。そして、単位発電量に対するＣＯ₂ 量を少なくでき、地球温暖化を少なくできる。
【０１３２】
複合発電は、起動停止が短時間で容易なガスタービンと小型で単純な蒸気タービンの組み合わせで成立っており、このため、出力調整が容易に出来、需要の変化に即応した中間負荷火力として最適である。
【０１３３】
ガスタービンの信頼性は、最近の技術の発展により飛躍的に増大しており、また、複合発電プラントは、小容量機の組み合わせでシステムを構成しているので、万一故障が発生してもその影響を局部にとどめることが出来、信頼性の高い電源である。
【０１３４】
実施例４
表１２に示す合金鋼の溶解を塩基性電気炉で行い、取鍋で十分精錬を行った。造塊に際しては、真空鋳込みを行うと同時に、真空カーボン脱酸を行った。次に水圧プレス機により熱間（８５０℃〜１２００℃）で鍛造し、６分割し、熱間でそれぞれのディスクに成型できる所定の寸法に仕上げた。本ロータ各部の機械的性質は表１３に示す如く、室温における引張強さ８５kg／mm² 以上、２０℃における衝撃吸収エネルギー２３kg−ｍ／cm² 以上で、脆化も認められず優れた性質を示すことが実証された。
【０１３５】
このロータはガスタービン用圧縮機のロータに使用できることが実証できた。表１３は代表的な圧縮機ロータの素材寸法，熱処理条件および中心部の機械的性質を示す。
【０１３６】
表１４は試料Ｎo.５について脆化試験後の衝撃値及びＦＡＡＴを示す。いずれの試験でもあまり脆化しないことが分る。
【０１３７】
【表１２】

【０１３８】
【表１３】

【０１３９】
【表１４】

【０１４０】
【発明の効果】
本発明によれば、全分割型ディスクに比較し部品数の低減し、形状を単純化することができ、その結果より高温高圧縮の空気を燃焼器及びタービン部の冷却として送ることができることから燃焼ガス温度の１４００℃以上というより高温化と効率的に冷却が可能となり、ガスタービンの熱効率の向上及びより効率の高い複合発電が達成される効果が得られる。
【図面の簡単な説明】
【図１】本発明に係るガスタービンの部分断面図。
【図２】本発明に係る圧縮機用ブレード（動翼）の斜視図。
【図３】本発明に係る圧縮機用ブレード（動翼）の斜視図。
【図４】ステップクール法の熱処理プロフィル図。
【図５】本発明に係る複合発電システムを示す構成図。
【図６】本発明に係る高低圧一体型蒸気タービンの部分断面図。
【符号の説明】
２…タービンノズル、３…タービンブレード、４…タービンディスク、５…燃焼器、６…圧縮機用分割型ロータ、７…コンプレッサブレード、８…タービンスペーサ、９，１０…軸受部、１１…タービンスタッキングボルト、１２…コンプレッサ用ノズル、１２′…コンプレッサ用可変ノズル、１３…ライナ、１４…ディスタントピース、１６…翼部、１７…プラットフォーム、１８…植込み部、 １９…ボルト、２３…高低圧一体型ロータシャフト、２４…蒸気タービンブレード、２６…ケーシング、２７…蒸気タービン用ノズル、３０…高圧部、３１…低圧部。[0001]
[Industrial application fields]
The present invention relates to a novel compressor for a gas turbine, a high-temperature gas turbine using the same, a compressor for the high-temperature gas turbine, a divided rotor for the compressor, and a heat-resistant steel for a divided rotor using the compressor.
[0002]
[Prior art]
A conventional compressor rotor of a large high-temperature gas turbine has a structure in which a disk (17 stages) is bolted as shown in JP-A-63-171856 and JP-A-2-101143. From the first stage to the 12th stage on the rotor air inlet (low temperature) side, high toughness 3% Ni-Cr-Mo-V low alloy steel is used. On the 13th to 16th stage on the rotor air outlet (high temperature) side, the high temperature strength is high. Cr-Mo-V low alloy steel and the use of martensite steel in the final stage. This divided rotor type compressor has problems such as significant manufacturing man-hours and low reliability against breakage.
[0003]
Mitsubishi Heavy Industries Technical Report, Vol. 27, No. 1 (1990-1) discloses a structure using an integral rotor shaft as a compressor of a small gas turbine.
[0004]
[Problems to be solved by the invention]
Disc type gas turbine rotors described in JP-A-63-171856 and JP-A-2-101143 take a lot of man-hours to manufacture, and loosening due to bolt creep when the compressor becomes hotter. Since this causes vibration, it takes a great deal of time for re-tightening, and it also takes a lot of labor to replace the blade when it is damaged.
[0005]
In recent years, gas turbines have a tendency to increase in size and capacity year by year, and therefore, tend to have higher temperatures.
[0006]
The compressor rotor of a large high-temperature gas turbine is used while rotating at high speed in a wide temperature range from room temperature to 500 ° C. For this reason, the integrated rotor has room temperature tensile strength ≧ 85kg / mm ² , 10 at fracture surface transition temperature ≦ 20 ° C. and 475 ° C. ^Five h Creep rupture strength ≧ 30kg / mm ² Materials are required. The above-mentioned Mitsubishi Heavy Industries Technical Bulletin does not disclose the rotor material, and the compressor temperature itself is low. Thus, the Ni-Cr-Mo-V steel described above has high low-temperature toughness while the high-temperature strength is low while Cr-Mo-V steel has high high-temperature strength but low low-temperature toughness. was there.
[0007]
The object of the present invention is that the compressor rotor can be constituted by an integral rotor shaft by using a material having both high temperature strength and low temperature toughness, thereby achieving higher temperature, higher efficiency and higher reliability. The present invention provides a high-temperature gas turbine, a compressor for the high-temperature gas turbine, a rotor for the high-temperature gas turbine compressor, and a low alloy steel used therefor.
[0008]
[Means for Solving the Problems]
The present invention relates to a gas turbine comprising a compressor and a turbine that is integrally connected to the compressor and that rotates at high speed by combustion gas generated by the combustor, wherein the compressor is installed in a rotor divided into a plurality of parts. The high-temperature gas turbine is characterized in that the blade has 12 or more stages, and a plurality of blades of 3 stages or less are implanted in one rotor from the first stage to at least 6 stages.
[0009]
Furthermore, the compressor according to the present invention has blades implanted in a plurality of divided rotors made of Ni-Cr-Mo-V based low alloy steel, and a plurality of at least six stages from the first stage to one rotor. Stepped blades are implanted, and at least the last step of the rotor is made of the low alloy steel, and its 50% fracture surface transition temperature is 20 ° C. or less and 475 ° C., 10 ^Five Time creep rupture strength is 30kg / mm ² It is the above.
[0010]
Furthermore, the compressor in the present invention has blades implanted in a rotor divided into a plurality of parts, and at least the final stage of the rotor is C0.15 to 0.40% by weight, Si 0.1% or less, Mn 0.5% or less, Ni 1.5-2.5%, Cr 0.8-2.5%, Mo 0.8-2.0%, V 0.1-0.35% and the balance is substantially Fe. It is characterized by being made of a Ni—Cr—Mo—V based low alloy steel having the entire bainitic structure.
[0011]
Low alloy steel is characterized by containing 0.01 to 0.1% of one or more of Nb and Ta.
[0012]
Furthermore, the compressor in the present invention has blades implanted in a plurality of divided rotors made of Ni-Cr-Mo-V based low alloy steel, and the diameter from the first stage to at least six stages is the same. The total length of the rotor between the blades is 3.0 to 4.0 with respect to the maximum diameter of the rotor or 3.7 to 4.7 with respect to the minimum diameter of the rotor.
[0013]
Further, the compressor according to the present invention has 15 or more blades implanted in a divided rotor divided into 6 parts, and 2 stages of blades are implanted from the first stage to the 8th stage, and the 9th and subsequent stages are 3 stages. It has the rotor by which the braid | blade of a step or more is implanted.
[0014]
Further, the compressor according to the present invention has 15 or more stages of blades implanted in the split rotor, and the blades are independent from the first stage to at least the fifth stage except for the last stage rotor. The rotor having a blade embedded structure and having three or more stages of blades has a structure in which the blade is implanted in a ring-shaped groove provided on the entire circumference of the rotor. And
[0015]
Further, the compressor according to the present invention has at least 15 stages of blades, each of which is divided into at least three divided rotors, and the blades are arranged in the first stage and, if necessary, the second stage to the fifth stage. It is characterized in that at least one stage is made of a Ti alloy, and the second and subsequent stages are made of martensitic stainless steel except for those made of the Ti alloy.
[0016]
The present invention comprises a gas turbine that is rotated by combustion gas, and a steam turbine that generates steam by a heat recovery steam generator that recovers heat of combustion exhaust gas that has exited the gas turbine, and that rotates by the steam. In the combined power generation system for generating power by rotating a generator with a steam turbine, the gas turbine has at least three divided-type rotors with compressors individually installed in a plurality of stages, and is compressed by the compressor. The air pressure ratio is 15 to 20 and its temperature is 400 ° C. or higher, the combustion gas outlet temperature is 1400 ° C. or higher, the combustion exhaust gas temperature is 550 to 600 ° C., and the steam turbine is a high-low pressure integrated rotor It consists of a shaft, the steam temperature is 530 ° C. or higher, the thermal efficiency is 46% or higher, and / or the specific power is 600 kW / (kg / S) or higher. It is in the combined power generation system characterized by this.
[0017]
Furthermore, the present invention comprises a gas turbine that is rotated by combustion gas, and a steam turbine that generates steam by the exhaust heat recovery boiler that recovers the heat of the combustion exhaust gas that has exited the gas turbine, and that is rotated by the steam. In a combined power generation system in which a generator is rotated by a gas turbine and a steam turbine to generate electric power, the gas turbine has at least three divided rotors individually implanted in a plurality of stages, and has a total of 15 to 20 blades. A combustor having a compressor, a pressure ratio of air compressed by the compressor of 15 to 20 and a temperature of 400 ° C. or more, and a turbine rotated by the combustion gas having at least three stages; The outlet temperature is 1400 ° C. or higher, and the temperature of the combustion exhaust gas at the exhaust heat recovery boiler inlet is 550 to 600 ° C. The temperature of the combustion exhaust gas is 130 ° C. or less, the steam turbine is provided with blades implanted in a high and low pressure integrated rotor shaft, the final stage of the blades is 30 inches or more at the blade portion, and the steam at the high pressure side inlet of the steam turbine The combined power generation system is characterized in that the temperature is 530 ° C. or higher and the low-pressure side outlet temperature is 100 ° C. or lower.
[0018]
Furthermore, the present invention provides a compressor for a gas turbine having blades implanted in multiple stages of 2 to 6 stages in a split rotor divided into at least three stages, and the rotor is C0.15 to 0.40 by weight. %, Si 0.1% or less, Mn 0.5% or less, Ni 1.5 to 2.5%, Cr 0.8 to 2.5%, Mo 0.8 to 2.0%, V 0.1 to 0.35% and In the compressor for a gas turbine, the balance is substantially Fe and is made of a Ni—Cr—Mo—V low alloy steel having a whole bainitic structure.
[0019]
Further, the present invention is C0.15-0.40%, Si0.1% or less, Mn0.5% or less, Ni1.5-2.5%, Cr0.8-2.5%, Mo0.8 by weight. Gas turbine compression characterized by ~ 2.0%, V 0.1 ~ 0.35% and the balance being substantially Fe, having a total bainitic structure, and blades having a 2-6 stage implant structure It is in the split rotor for machines.
[0020]
Furthermore, the present invention provides C0.15-0.40% by weight, Si 0.1% or less, Mn 0.5% or less, Ni 1.5-2.5%, Cr 0.8-2.5%, Mo0. .8 to 2.0%, V0.1 to 0.35%, and the balance is substantially Fe, has a whole bainitic structure, and has a structure in which blades are implanted in two to six stages. It is in heat resistant steel for gas turbine compressor split rotor.
[0021]
[Action]
By using a split-type rotor as the compressor of the present invention, it is possible to obtain higher temperature air by eliminating bolt tightening as compared with a conventional disk type, particularly 400 ° C. or more, preferably 450 to 500 ° C. Of 46% or more is expected as thermal efficiency. In particular, since there is no problem of bolt creep deformation in bolt tightening as compared with a conventional disk type, maintenance and inspection are simplified, and there are few problems in balance of rotation. In particular, by using heat-resistant steel having an alloy composition having specific characteristics described later, blade implantation is effective for a large size of 15 stages or more, and the maximum diameter (D) and the length from the first stage to the last stage implantation part. There is an advantage that the same structure as the disk type in which the ratio (D / L) to (L) is 0.4 to 0.55 can be adopted as it is. The blade is more preferably 17 stages or more, and is effective in that the 18th to 20th stages can be made higher. As a result, the pressure ratio can be increased to 15 to 20, and 16 to 18 is particularly preferable.
[0022]
The use of Ni-Cr-Mo-V low alloy steel as a rotor for a large-sized high-temperature gas turbine compressor of the present invention is excellent in mechanical properties such as high-temperature strength and toughness, particularly high bearing characteristics, What has a return bainitic structure is good.
[0023]
C is an element necessary for improving hardenability and ensuring strength. If the amount is 0.15% or less, sufficient hardenability cannot be obtained, and a soft ferrite structure is formed at the center of the rotor, and sufficient tensile strength and yield strength cannot be obtained. Moreover, since it will reduce toughness when it becomes 0.40% or more, the range of C is limited to 0.15 to 0.40%. In particular, C is preferably in the range of 0.20 to 0.28%.
[0024]
Si and Mn are added as a deoxidizing agent. However, according to steelmaking techniques such as a vacuum C deoxidizing method and an electroslag remelting method, a healthy rotor can be melted without particular addition. From the viewpoint of temper embrittlement, Si and Mn should be kept low, and are limited to 0.1% and 0.5% or less, respectively. In particular, Si is 0.05% or less, and Mn is 0.1 to 0. 0.3%, more preferably 0.15 to 0.25%. In addition, the Mn content is 0.1% or less for the high Ni steel described later, the Mn content is 0.5 to 1.0% and the Si content is 0.1 to 0.5% for the low Ni steel. It is preferable that
[0025]
Ni is an essential element for improving hardenability and improving toughness. If it is less than 1.5%, the effect of improving toughness is not sufficient. Addition of a large amount exceeding 2.5% reduces the creep rupture strength. In particular, an amount exceeding 1.5% is preferable, and a range of 1.6 to 2.0% is more preferable. Further, a high Ni content of 3 to 5% is preferable for the low temperature portion on the upstream side. Further, Ni is preferably 0.1 to 0.7% with respect to the temperature of the intermediate portion.
[0026]
Cr has the effect of improving hardenability and improving toughness. It also has the effect of improving oxidation resistance at high temperatures. If the content is less than 0.8%, these effects are not sufficient, and a large amount of addition exceeding 2.50% lowers the creep rupture strength. In particular, the range is 1.2 to 2.2%, and more preferably 1.8 to 2.2%.
[0027]
Mo has the effect of precipitating fine carbides in the crystal grains during the tempering treatment and increasing the high temperature strength and the high temperature ductility. In addition, it has the effect of suppressing the segregation of impurity elements to the crystal grain boundaries during tempering, and therefore has the effect of preventing tempering and embrittlement. If it is less than 0.8%, these effects are not sufficient, and even if it is added in a large amount exceeding 2.0%, the effect tends to be saturated. In particular, 1.0 to 1.7% is preferable. Moreover, it is preferable to set it as 0.2 to 0.7% with respect to the above-mentioned high Ni steel.
[0028]
V precipitates fine carbides in the crystal grains during the tempering treatment, and has a high temperature strength toughness improver. If it is less than 0.10%, these effects are not sufficient, and if it is added in a large amount exceeding 0.35%, the effect tends to be saturated. In particular, the range of 0.21 to 0.28% is preferable, and in order to obtain higher toughness, it is more than 0.25% and less than 0.35%. Moreover, it is preferable to set it as 0.05-0.2% with respect to the above-mentioned high Ni steel.
[0029]
Furthermore, an increase in inevitable impurity elements reduces toughness and should be kept low. In particular, the reduction of Al has a great effect of improving toughness. The upper limit of Al is 0.01% from the viewpoint of securing toughness. In particular, 0.005% or less is preferable.
[0030]
In order to increase the toughness of the Ni-Cr-Mo-V steel, at least one of Nb and Ta is added to any alloy. If the content is less than 0.01%, a sufficient toughness improving effect cannot be obtained, and if added in a large amount exceeding 0.1%, the toughness and the high-temperature strength are lowered. In particular, 0.015 to 0.045% is preferable.
[0031]
The strength can be further increased by adding one or more of rare earth elements of 0.4% or less, Ca, Mg of 0.1% or less, Zr, Hf of 0.1% or less, and W of 0.1% or less. Next, the manufacturing method of the rotor for large-sized high temperature gas turbine compressors of this invention is demonstrated.
[0032]
The steel ingot is subjected to tempering heat treatment after hot forging and diffusion annealing. Quenching in the tempering heat treatment is rapidly cooled to austenitizing temperature of 800 to 1000 ° C. by blast, water spray or liquid (water or oil) after heating. Next, it is heated and held at 550 to 700 ° C. and tempered. The austenitizing temperature must be heated above 800 ° C. to obtain high tensile strength and high creep rupture strength. When heated to 1000 ° C. or higher, the crystal grain size becomes coarse and the toughness decreases. In tempering, high toughness cannot be obtained at 550 ° C. or lower, and tensile strength and creep rupture strength are decreased at 700 ° C. or higher.
[0033]
In order to manufacture a rotor for a large-scale high-temperature gas turbine compressor with higher reliability, the quenching temperature in the tempering heat treatment is set so that the rotor air inlet side (low temperature of 350 ° C. or lower) is lowered and the rotor air outlet side ( It is preferable to heat and quench to a high temperature (400 ° C. or higher). The quenching temperature on the rotor air inlet (low temperature) side is 850 to 925 ° C. in order to refine the crystal grain size and obtain high toughness, and the rotor air outlet (high temperature) side is 925 to obtain high creep rupture strength. It is preferable to heat quench at a temperature of 975 ° C. and then to perform a tempering treatment at a temperature of 550 to 700 ° C. The tempering treatment is preferably repeated twice from the viewpoint of obtaining decomposition of retained austenite and high toughness.
[0034]
In order to manufacture a highly reliable rotor material for large high-temperature gas turbine compressors, the rotor air inlet (low temperature) side is made of high toughness steel and the rotor air outlet (high temperature) side is made high by electroslag remelting. It is preferable to ingot with high-temperature strength steel and to perform quenching and tempering treatment after hot forging and diffusion annealing.
[0035]
Next, the rotor, blades, and cooling air introduction holes of the gas turbine disk for the large-sized high-temperature gas turbine compressor of the present invention will be described.
[0036]
The rotor for a large high-temperature gas turbine compressor must be provided with cooling air introduction holes that are cooled by compressed air for cooling the gas turbine disks and turbine blades. The cooling air introduction hole can be provided in a flange portion provided in the rotor. In addition, the cooling air introduction hole can be divided into two rotors after the last stage blade and before the last stage blade, and a cooling air introduction hole can be provided therebetween.
[0037]
The blades of the rotor for large high-temperature gas turbine compressors are planted with blades made of Ti alloy with high specific strength from the first stage to the fifth stage with a long blade length, and 12Cr alloy steel from the sixth stage to the last stage. Thereby, it can be set as the reliable compressor for gas turbines.
[0038]
The blade shape of the split rotor for a large high-temperature gas turbine compressor is preferably such that the hook length L is not more than half of the blade pitch (P).
[0039]
As a rotor material for a compressor, C 0.05 to 0.2% by weight, especially 0.07 to 0.15%, Si 0.1% or less or no addition, Mn 0.4% or less, particularly 0.1 to 0 .25%, Ni2 to 3%, especially 2.3 to 2.7%, Cr8 to 13%, especially 11 to 12.5%, Mo 1.5 to 3%, especially 1.8 to 2.5%, V0 0.1 to 0.3%, especially 0.15 to 0.25%, Ta, Nb 0.02 to 0.2%, especially 0.04 to 0.08%, N 0.03 to 0.1%, especially 0 0.04 to 0.08%, all tempered martensitic steel consisting essentially of Fe, or Co 0.5% or less, W 0.5% or less, B 0.01% or less, Al 0.1% or less, Ti0 One or more of 0.3% or less, Zr, Hf of 0.1% or less, Ca, Mg, Y and rare earth elements of 0.01% or less may be included. The material of this system has high temperature strength and high toughness, and is sufficiently satisfactory as a rotor material. However, since bearing characteristics are low, C0.1-0.3%, Si1% or less, Mn2% or less, It is preferable to provide a steel having Cr of 0.5 to 3% or a material having a bainite structure containing Mo of 1% or less and V of 0.3% or less as a sleeve or by multilayer overlay welding.
[0040]
As the blade for the compressor, 12% Cr martensite steel and Ti alloy can be used. The former is used for moving blades and stationary blades except for those using Ti alloy, and by weight, C is 0.1 to 0.2%, Si is 0.3% or less, Mn is 1% or less, Cr is 9 to 13%, and Mo is 0.5. Forged steel consisting of ˜2%, V0.05 to 0.2% and the balance Fe, and the latter can be used as needed from the first stage or the second stage to the fifth stage, C0.05% or less, V3 A Ti alloy consisting of 6%, Al 5-8%, Fe 1% or less and the balance Ti is preferred. In particular, it is preferable that the blade has a structure in which the tip is wider than the implanted portion because high compression can be obtained. A blade made of a Ti alloy has a structure in which the tip is smaller in width than the implanted portion, or conversely, a blade having a tip wider than the implanted portion from the first stage to the third stage is used, and the latter is preferable in view of efficiency.
[0041]
The gas turbine according to the present invention preferably has the following configuration.
[0042]
In addition to the compressor rotor, at least one or more of the distant piece, turbine spacer, turbine stacking bolt, compressor stacking bolt, and compressor disk at the final stage is C0.05 to 0.2% by weight, Si 0.5% or less, Mn 1% or less, Cr 8 to 13%, Ni 3% or less, Mo 1.5 to 3%, V 0.05 to 0.3%, Nb 0.02 to 0.2%, N 0.02 to 0.1% and the balance are substantially In particular, it can be made of a heat-resistant steel having a total tempered martensite structure made of Fe. By configuring all of these parts with this heat-resistant steel, a higher gas temperature can be obtained, and an improvement in thermal efficiency can be obtained. In particular, at least one of these parts is by weight: C 0.05 to 0.2%, Si 0.5% or less, Mn 0.6% or less, Cr 8 to 13%, Ni 2 to 3%, Mo 1.5 to 3%, V 0.05 to 0.3%, Nb 0.02 to 0.2%, N 0.02 to 0.1% and the balance substantially consisting of Fe, and the (Mn / Ni) ratio is 0.11 or less, especially 0 A highly safe gas turbine is obtained which is made of a heat resistant steel having a total tempered martensite structure and which has high embrittlement resistance.
[0043]
As materials used for these parts, 10 ^Five h Creep rupture strength is 40kg / mm ² The 20 ° C V-notch Charpy impact value is 5 kg-m / cm. ² The above martensitic steels are used, but in a particularly preferred composition 10 at 450 ° C. ^Five h Creep rupture strength is 50kg / mm ² 10 in the above and 500 ^Five h 20 ° C notch Charpy impact value after heating is 5kg-m / cm ² It has the above.
[0044]
These materials further include W 1% or less, Co 0.5% or less, Cu 0.5% or less, B 0.01% or less, Ti 0.5% or less, Al 0.3% or less, Zr 0.1% or less, Hf 0.1. % Or less, Ca 0.01% or less, Mg 0.01% or less, Y 0.01% or less, and rare earth elements 0.01% or less.
[0045]
In the diaphragm for fixing the turbine nozzle, the turbine nozzle part of the first stage is by weight, C 0.05 or less, Si 1% or less, Mn 2% or less, Cr 16-22%, Ni 8-15%, and the balance is substantially made of Fe. The turbine nozzle portion is made of a high C-high Ni steel casting.
[0046]
Turbine blades are by weight 0.07 to 0.25%, Si 1% or less, Mn 1% or less, Cr 12 to 20%, Co 5 to 15%, Mo 1.0 to 5.0%, W 1.0 to 5.0%, B0 0.005 to 0.03%, Ti 2.0 to 7.0%, Al 3.0 to 7.0%, Nb 1.5% or less, Zr 0.01 to 0.5%, Hf 0.01 to 0.5% , V of 0.01 to 0.5%, and a cast alloy in which the balance is substantially made of Ni and the γ ′ phase and γ ″ phase are precipitated on the austenite base is used. Especially at higher temperatures. Is a single crystal alloy further containing Re 5% or less or Y ₂ O _Three A dispersion alloy, a unidirectionally solidified alloy, or the like in which a particle diameter of 0.1 μm or less is uniformly dispersed by 1% by weight or less is used.
[0047]
The gas turbine nozzle is provided with a Ni-base superalloy described later at least in the first stage, but can be used in all stages. Other than the first stage, by weight, C 0.20 to 0.60%, Si 2% or less, Mn 2% or less, Cr 25 to 35%, Ni 5 to 15%, W 3 to 10%, B 0.003 to 0.03%, and the balance It consists essentially of Co or further contains at least one of Ti 0.1 to 0.3%, Nb 0.1 to 0.5% and Zr 0.1 to 0.3%, and has an eutectic carbide in the austenitic phase base. And a cast alloy containing secondary carbide. All of these alloys are subjected to a solution treatment and then an aging treatment to form the aforementioned precipitates and strengthen them.
[0048]
As the first stage mentioned above, especially 900 ° C, 14kg / mm ² Ni-based super alloy having a specific composition that has a fracture strength of 300 h or more, a heat fatigue resistance of 900 ° C. and 350 ° C. of 600 times or more, and a weldability at a preheating temperature of 400 ° C. or less. An alloy is preferable, and it has one wing portion and sidewalls formed at both ends of the wing portion, and is arranged in a ring shape on the outer periphery of the rotating blade, and has a weight of C 0.05 to 0.20%. , Co 15-25%, Cr 15-25%, Al 1.0-3.0%, Ti 1.0-3.0%, Nb 1.0-3.0%, W 5-10% and 55% or more of Ni, (Al + Ti) amount and W amount in FIG. 5 are A (Al + Ti 2.5%, W 10%), B (Al + Ti 3%, W 10%), C (Al + Ti 5%, W 7.5%), D (Al + Ti 5%, W 5%). , E (Al + Ti 3.5%, W 5%) and F (Al + T 2.5%, Ni base superalloy preferably is within sequentially connecting lines each point W7.5%). The turbine nozzle is 900 ° C, 14kg / mm ² A Ni-based alloy having a preheating temperature of 400 ° C. or less at which cracking does not occur in a bead formed by TIG welding of one pass with a break time of 300 hours or longer, a length of 80 mm and a width of 8 mm is preferable.
[0049]
The gas turbine of the present invention is preferably a Ni-base superalloy casting in which the distance between the sidewalls at both ends of the nozzle blade is 70 mm or more and the length from the combustion gas inlet side to the outlet side is 100 mm or more.
[0050]
Further, the turbine blade can be coated with Al, Cr or Al + Cr diffusion coating to prevent corrosion due to high-temperature combustion gas. The coating layer has a thickness of 30 to 150 μm and is preferably provided on the wing portion in contact with the gas. Instead of this diffusion coating, Ni or Fe alloy containing 10-30% Cr, 5-10% Al, Y1% or less is vapor-phased or plasma sprayed and then stabilized as a thermal barrier ZrO ₂ The layer is preferably formed by gas phase or plasma spraying.
[0051]
A plurality of combustors are provided around the turbine and have a double structure of an outer cylinder and an inner cylinder. The inner cylinder is C0.05 to 0.2% by weight, Si2% or less, Mn2% or less, Cr20 to 25%, Co 0.5 to 5%, Mo 5 to 15%, Fe 10 to 30%, W 5% or less, B 0.02% or less, and the balance consisting essentially of Ni, welding a plastic workpiece with a thickness of 2 to 5mm A solution treatment material having a total austenite structure is used, which is provided with a crescent-shaped louver hole for supplying air over the entire circumference of the cylindrical body. Moreover, although the transition piece which narrows down combustion gas is provided after a combustor, the above-mentioned material can be used also with respect to this material.
[0052]
In the present invention described above, in particular, the rotor as a steam turbine comprising a rotor in which blades are planted in multiple stages from the high pressure side to the low pressure side on the high and low pressure integrated steam turbine rotor shaft, and a casing covering the rotor. The shaft is made of a heat-resistant low alloy steel containing Ni—Cr—Mo—V having a bainite structure, and the steam at a temperature of 538 ° C. or 566 ° C. is introduced into the first stage blade, and the temperature at the last stage blade is 46 ° C. or less. It is characterized by being constituted by an integral shaft through the low pressure side from which the temperature steam is discharged.
[0053]
The rotor shaft is made of a heat-resistant low alloy steel containing Ni—Cr—Mo—V having a bainite structure, and 100 ° C. at the last stage blade from the high pressure side where steam at a temperature of 530 ° C. or more is introduced into the first stage blade. It is constituted by an integral shaft through the low pressure side discharged as steam at the following temperature, the last stage blade has a blade length of 33.5 inches or 40 inches, and from the first stage to 33.5 inches, chromium 10 It is made of martensitic steel containing 13%, and a 40-inch blade is made of a Ti-based alloy.
[0054]
The steam turbine according to the present invention has a steam temperature of 530 ° C. or higher, flows out at a low pressure side of 100 ° C. or lower, and flows in one direction from the high pressure side to the low pressure side. There is a reheat type steam turbine which is heated to a temperature and flows into the intermediate pressure side, and it is preferable that the rotor blade has 10 stages or more, and the blade part length is preferably 30 inches or more as described above.
[0055]
【Example】
Example 1
Table 1 shows the material chemical composition (% by weight) used for the divided rotor according to the present invention. These samples were melted in a high-frequency melting furnace and hot forged. No.1 is ASTM standard A470 Class8 equivalent Cr-Mo-V steel, No.2 is ASTM standard A470 Class7 equivalent 3.5Ni-Cr-Mo-V steel, No.3 and No.4 are 2Cr-2Ni. -Mo-V steel. These samples were subjected to quenching and tempering heat treatment as shown in Table 2.
[0056]
[Table 1]

[0057]
[Table 2]

[0058]
Table 3 shows the mechanical properties of these rotor materials. The room temperature tensile test, V-notch Charpy impact test and creep rupture test were performed according to the JIS test method. The impact test is shown below, which simulates high temperature long time embrittlement. It implemented after the step cool embrittlement process shown in FIG.
[0059]
[Table 3]

[0060]
Creep rupture strength was determined by the Larson-Miller method. Mechanical properties required for rotor materials used in the hottest part (room temperature tensile strength ≥ 85 kg / mm ² , Fracture surface transition temperature ≤ 20 ° C, 538 ° C, 10 ^Five h Creep rupture strength ≧ 30kg / mm ² ) And the properties of this test steel, No.1 has a high fracture surface transition temperature and lacks low-temperature toughness, but satisfies room temperature tensile strength and creep rupture strength, so it can be applied to rotor e in relatively high temperature areas. Is done. No. 2 has low creep rupture strength and insufficient high-temperature strength, but satisfies room temperature tensile strength and fracture surface transition temperature, so it is applied to the upstream rotors a to d having low temperature.
[0061]
In contrast, No. 3 and No. 4 sufficiently satisfy room temperature tensile strength, fracture surface transition temperature, and creep rupture strength, and are extremely useful for the high temperature part of the rotor materials of compressors e and f. It can be said. The whole can be constituted by this material. It is advantageous from the viewpoint of management and manufacturing that the whole is composed of the same material.
[0062]
FIG. 1 is a partial cross-sectional view of a rotating portion of a gas turbine having a gas turbine compressor comprising a six-split rotor of the present invention.
[0063]
10 is a turbine stub shaft, 3 is a turbine blade, 11 is a turbine stacking bolt, 8 is a turbine spacer, 14 is a distant piece, 2 is a turbine nozzle, 6 is a divided rotor for a compressor, 7 is a compressor blade, 9 is a compressor stub A bearing portion of the shaft, 4 is a turbine disk, and 11 is a hole. The gas turbine of the present invention has 17 stages of compressor blades 7 and 3 stages of turbine blades 3.
[0064]
The main type of the gas turbine in this embodiment is a heavy duty type, a single shaft type, a horizontally divided casing, and a stacking type rotor, a compressor is a 17-stage axial flow type, a turbine is a 3-stage impulse type, and a 1, 2-stage air Cooling stationary blades and combustors have a berth flow type, 16 cans, and a slot cool system.
[0065]
In FIG. 1, the divided rotor a has 1 and 2 blades, b has 3 and 4 blades, c has 5 and 6 blades, d has 7 and 8 blades, e has 9, and The structure is such that 10 and 11 stage blades and 12 to 14 stage blades are implanted in f, and are joined together by bolts 19. Each rotor is connected by a bolt 19 between the implantation of the second stage blade and the last stage blade. The rotor f is integrated with the distant pieces 14 and 14 'by bolts. The distance piece 14 'has a structure in which 15 to 17 stage wings are implanted. Any of these bolts are made of heat-resistant steel, and 10 or more bolts are used on the entire circumference. Since the rotors a to e are used at 350 ° C. or lower, high temperature strength (creep rupture strength) is not required, but high low temperature toughness is required. In particular, since the rotor a is provided with a bearing portion and long blades are implanted, it receives the highest centrifugal stress and is used at the lowest temperature (35 ° C.). Therefore, the rotor a is required to have the highest low temperature toughness. On the other hand, since the rotor f is exposed to the highest temperature (≦ 400 ° C.), high creep rupture strength and excellent oxidation resistance are required.
[0066]
In each of the rotors a to d, two stages of blades of FIG. 3 are implanted in each rotor in a groove provided obliquely along the axial direction of the rotor shaft, and three stages of blades are implanted in the rotors e and f. The blade of FIG. 3 is implanted on both sides, and the blade of FIG. 2 is implanted in a groove provided on the circumference of the rotor center at the center. On the downstream side of the rotor f, a dirt piece 12 is provided, three stages of blades are implanted, the blades of FIG. 3 are implanted on both sides in the same manner as the rotors a to d described above, and Two blades are implanted in grooves provided on the circumference in the same manner as described above. The rotors a to c all have the same diameter, and the diameters of the rotors d and e gradually increase in accordance with the diameters of the rotors c and f, and the diameter of the rotor f is maximized. The overall length between blade implantations in this embodiment is 3.4 to 3.8 times the maximum rotor diameter or 4.0 to 4.4 times the minimum diameter. A space is provided in the center between the rotors to reduce the weight. The lengths of the blades implanted in the rotor f and the dirt piece 14 are the same, and the lengths of the other blades are gradually shortened from the first stage to the downstream side. The length of the blade is 3.45 times the length of the first stage with respect to the last stage, preferably 3 to 4 times. The rotors b to f are disk-shaped, and d to f are provided with ring-shaped spaces that are lightweight just below the blade implantation portion. The central part between the rotors is hollow and lightened.
[0067]
The distance between the blades gradually decreases from the first stage to the eighth stage, the third stage from the 8th to the 10th stage is set to the same spacing, the same spacing is set to the 11th stage to the 17th stage, and the spacing is further smaller than the 8th to 10th stage. Become. The blade interval between the first stage and the second stage is about 2.7 to 3.2 times the distance between the last stage and the front stage, and the blade length of the first stage is about 3.5 to 4.2 than the length of the last stage. Double.
[0068]
Regarding the materials shown in Table 4, large steels corresponding to the actual products as various members for gas turbines were melted by electroslag remelting and subjected to forging and heat treatment. Forging was performed within a temperature range of 850 to 1150 ° C., and heat treatment was performed under the conditions shown in Table 6. Table 6 shows the chemical composition (% by weight). As for the microstructure of these materials, Nos. 5 to 8 were all tempered martensite structures, and No. 9 was all tempered bainitic structures. No.5 is used for the distance piece and the final stage compressor disk, the former is 60mm thick x 500mm wide x 1000mm long, the latter is 1000mm in diameter and 180mm in thickness, and No.21 is 1000mm in diameter and thickness as a disk. 180mm, No.7 is the outer diameter 1000mm x inner diameter 400mm x thickness 100mm as spacer, No.8 is the diameter 40mm x length 500mm as the turbine stacking bolt, and the bolt that connects the distant piece and the turbine disk in the same way Also manufactured. No. 9 was forged as a turbine stub shaft to a diameter of 250 mm and a length of 300 mm. After heat treatment, the test piece was sampled in the direction perpendicular to the axial (longitudinal) direction, except for No. 8, from the center portion of the sample. In this example, specimens were collected in the longitudinal direction.
[0069]
[Table 4]

[0070]
Table 5 shows the room temperature tension, 20 ° C. V notch Charpy impact, and creep rupture test results. 450 ℃ × 10 ^Five h Creep rupture strength was determined by the commonly used Larson-Miller method.
[0071]
No. 5-8 (12% Cr steel) of the present invention is 450 ° C., 10 ^Five h Creep rupture strength is 50kg / mm ² Above, 20 ℃ V notch Charpy is 7kg-m / cm ² As described above, it was confirmed that the strength required for a high-temperature gas turbine material was sufficiently satisfied.
[0072]
[Table 5]

[0073]
Next, stub shaft No. 9 (low alloy steel) has a low creep rupture strength at 450 ° C, but a tensile strength of 86 kg / mm. ² Above, 20 ° C V notch Charpy impact value is 7kg-m / cm ² This is the strength required for a stub shaft (tensile strength ≥ 81 kg / mm ² , 20 ℃ V notch Charpy impact value ≧ 5kg-m / cm ² ) Was sufficiently satisfied.
[0074]
Under such conditions, the temperature of the distance piece and the temperature of the compressor rotor shaft portion at the final stage are 450 ° C. at the maximum. The former thickness is preferably 25 to 30 mm. The turbine disk is provided with a through hole in the center. A compressive residual stress is formed in the through hole in the turbine disk.
[0075]
The turbine disk 10 has three stages, and a center hole 11 is provided in the first stage and the second stage on the gas upstream side. In this embodiment, the turbine blade 3, the turbine nozzle 14, the liner 13 of the combustor 5, the compressor blade 7, the compressor nozzle 12, the diaphragm 15, and the shroud 1 are made of the alloy shown in Table 8. In particular, the turbine nozzle 2 and the turbine blade 3 are made of a casting. A Ni-based alloy was used for the first stage of the turbine nozzle, and a Co-based alloy was used for the second and third stages.
[0076]
The shroud segment (1) in Table 6 was used in the first stage upstream of the gas, and (2) was used in the second and third stages.
[0077]
[Table 6]

[0078]
The combustor liner 13, the rotor blade 3 and the stationary blade 2 have Y ₂ O _Three A thermal barrier coating layer of the stabilized zirconia sprayed layer (or CVD coating) is provided on the portion in contact with the flame. In particular, an alloy layer made of the remaining Ni or Ni + Co containing Al 2 to 5%, Cr 20 to 30%, Y 0.1 to 1% by weight is provided between the base metal and the coating layer.
[0079]
2 and 3 are perspective views showing the shapes of the blades for the split rotor compressor of the present invention.
[0080]
In the case of an integrated rotor compressor for a gas turbine, the blade can be implanted by setting the hook length L of the blade to L ≦ P / 2 (where P is the pitch of the blade). The blade has a wing part 16, a platform part 17, and an implanted part 18, and the platform part 17 is provided with a projection 19 on the implanted part side.
[0081]
In the case of a large compressor, since the blade is long on the air inlet side, a high centrifugal force is required, so a material with high specific strength is required. On the other hand, since the blade on the air outlet side is exposed to a high temperature, a material having high creep strength is required.
[0082]
In this example, the No. 11 Ti-6Al-4V alloy with low specific gravity and high tensile strength from the first stage to the fifth stage shown in Table 7 and No. 11 with the high temperature strength from the sixth stage to the 17th stage. Ten 12Cr heat resistant steels were used.
[0083]
[Table 7]

[0084]
The Ti-6Al-4V alloy blade was annealed at 705 ° C. after hot forging.
[0085]
The 12Cr heat-resistant steel blade was subjected to 1100 ° C. oil quenching and 650 ° C. tempering after melting and hot forging.
[0086]
Table 8 shows the mechanical properties of the compressor blades.
[0087]
By using a Ti alloy having a high specific strength on the air inlet side and a 12Cr heat resistant steel having a high creep strength on the air outlet side, a highly reliable compressor can be obtained.
[0088]
[Table 8]

[0089]
For the nozzle in this embodiment, SUS410 or SUS410J1 containing Mo is used.
[0090]
In this embodiment, the blade forms a ring-shaped groove having a cross-sectional shape of the implanted portion of the blade 7 in the case where the blade is formed with an oblique axis in the axial direction on the circumferential surface of the rotor 6 (FIG. 3). However, there is a case where a groove is provided in a hole having a size in which only one implantation portion is inserted in the ring-shaped groove, and a blade is implanted from that portion (FIG. 2). In the latter, the first and last blades are further adjusted so that the implant does not come out of this hole. Each blade is fixed in contact with each other at the platform. The protrusion 19 of the blade is implanted inside the rotor shaft so that the platform portion is the same surface as the rotor shaft surface. The latter is formed at a portion corresponding to the central part of e and f of the rotor, and the other is formed by the former groove formation.
[0091]
The above configuration enables a compression ratio of 15 to 18, a temperature of 400 to 500 ° C., a compression efficiency of 86% or more, a gas temperature of the first stage turbine nozzle inlet of 360 ° C. or more, an exhaust temperature of 530 ° C. or more, and a thermal efficiency of 35% or more. As mentioned above, the turbine disk, the distant piece, the spacer, the compressor rotor shaft, and the stacking bolt are made of heat-resistant steel with high creep rupture strength and less heat embrittlement as described above, and the turbine blade has high high-temperature strength. The turbine nozzle has high temperature strength and high temperature ductility, and the combustor liner is similarly made of an alloy with high temperature strength and fatigue resistance, so that a more reliable and balanced gas turbine can be obtained. is there. Natural gas and light oil are used as fuel.
[0092]
Most gas turbines have an intercooler, but the present invention is particularly suitable for this because the nozzle is hotter without the intercooler. In this embodiment, about 40 nozzles for the turbine are provided in the first stage on the entire circumference.
[0093]
Example 2
Next, a split-type rotor was manufactured by electroslag remelting method (hereinafter abbreviated as ESR method) using two kinds of electrodes.
[0094]
Materials having high low-temperature toughness were used for the rotors a to c on the air inlet side, and materials having high high-temperature strength were used for the rotors d to f and the distant piece 14 ′ on the air outlet side. These steel ingots were subjected to heat treatment after hot forging.
[0095]
Table 9 shows the chemical composition (% by weight) of the compressor ESR rotor material, Table 10 shows the heat treatment conditions, and Table 11 shows the mechanical properties of the compressor ESR rotor material.
[0096]
The compressor ESR rotor has extremely high low temperature toughness required on the air inlet side and high temperature strength required on the air outlet side, and is extremely excellent in reliability.
[0097]
[Table 9]

[0098]
[Table 10]

[0099]
[Table 11]

[0100]
80kg / mm tensile strength on the air inlet side ² Above, V-notch impact value is 15kg-m / cm ² Above, high toughness of FATT 0 ℃ or less, tensile strength 80kg / mm on the air outlet side ² 150 ° C, 10 ^Five h Creep rupture strength of 35 kg / mm ² Above, preferably 40kg / mm ² The above is obtained.
[0101]
The blade and nozzle in this embodiment are the same as those in the first embodiment.
[0102]
Example 3
FIG. 5 is a schematic diagram showing a single-shaft combined cycle power generation system that uses the gas turbine of Example 1 or 2 and is used in combination with a steam turbine. A plurality of these gas turbines and steam turbines can be combined to generate electric power, and can be combined in units of three or six.
[0103]
In the case of generating power using a gas turbine, in recent years, the gas turbine is driven by using liquefied natural gas (LNG) as fuel, and the steam turbine is driven by steam obtained by collecting exhaust gas energy of the gas turbine. There is a tendency to adopt a so-called combined power generation system in which a generator is driven by a gas turbine. When this combined power generation method is adopted, it is possible to significantly improve the thermal efficiency to 46% or more as compared with the thermal efficiency of 40% in the case of a conventional steam turbine alone.
[0104]
In such a combined power plant, recently, liquefied natural gas (LNG) exclusively burned to liquefied petroleum gas (LPG) can be used, and LNG and LPC can be mixed and fired, facilitating plant operation and economic efficiency. It is intended to improve.
[0105]
First, the air passes through the intake filter and the intake siren and enters the air compressor of the gas turbine. The air compressor compresses the air and sends the compressed air to the low NOx combustor.
[0106]
In the combustor, fuel is injected into the compressed air and burned to form a high-temperature gas of 1400 ° C. or higher. This high-temperature gas works in the gas turbine and generates power.
[0107]
The combustion exhaust gas of 550 ° C. or more discharged from the gas turbine is sent to the exhaust heat recovery boiler through the exhaust silencer, and the high-pressure steam and the low-pressure steam of 530 ° C. or more are recovered through the low-pressure steam pipe and the high-pressure steam respectively. It is sent from the main steam pipe to the steam turbine. This boiler is provided with a denitration device by dry ammonia catalytic reduction. The exhaust gas is discharged to the outside from a chimney of several hundreds of meters in a tripod assembly type.
[0108]
The generated high and low pressure steam is sent to a steam turbine composed of a high and low pressure integrated rotor. The steam turbine will be shown later.
[0109]
Further, the steam that has exited the steam turbine flows into the condenser and becomes the condensate that has been evacuated to vacuum, and the condensate is pressurized by the condensate pump and supplied to the boiler again as feed water. And a gas turbine and a steam turbine each drive a generator from the both shaft ends, and electric power generation is performed. For cooling the gas turbine blades used for such combined power generation, steam used in the steam turbine may be used as a cooling medium. In general, air is used as a cooling medium for the blades, but steam has a much larger specific heat than air and has a large cooling effect due to its light weight. When the steam used for cooling is released into the mainstream gas because of its large specific heat, the temperature of the mainstream gas is drastically reduced and the efficiency of the entire plant is reduced, so that steam at a relatively low temperature (for example, about 800 ° C) in the steam turbine is used. Supply from the cooling medium supply port of the gas turbine blade, cool and heat exchange the blade body, collect the cooling medium that has become relatively high temperature (for example, about 900 ° C.) and return it to the steam turbine, It is possible to prevent the mainstream gas temperature (about 1300 ° C. to 1550 ° C.) from being lowered and to improve the efficiency of the steam turbine, and hence the efficiency of the entire plant. With this combined power generation system, it is possible to obtain a total of 90,000 kW of power with a gas turbine of about 60,000 kW and a steam turbine of 30,000 kW. It is possible to manufacture economically for the same power generation capacity, and to obtain a great merit of being able to operate economically against fluctuations in the amount of power generation.
[0110]
Any of the gas turbines described in Example 1 or 2 can be applied to the gas turbine, and the air compressed by the compressor is sent to the combustor and burned to a high temperature of 1400 ° C. or higher. The disk in which the blade is implanted is rotated.
[0111]
FIG. 6 is a partial sectional view of a reheat type high / low pressure integrated steam turbine according to the present invention. By increasing the steam pressure at the main steam inlet of the high and low pressure integrated steam turbine to 100 atg or more and the temperature to 530 ° C or more, the output of the single unit of the turbine can be increased. Increasing the single machine output requires increasing the blade length of the final stage rotor blade and increasing the steam flow rate. For example, if the blade length of the last stage blade is changed from 26 inches to 33.5 inches, the annulus area increases by about 1.7 times. Therefore, if the blade length is increased from the conventional output of 100 MW to 1700 MW to 40 inches, the single-machine output can be increased more than twice.
[0112]
When Cr-Mo-V steel containing 0.5% Ni is used for a high-low pressure integrated rotor as a rotor shaft material for a length of 33.5 inches or more, this rotor material is originally used in a high temperature region. Therefore, since it is excellent in high temperature strength and creep characteristics, it can sufficiently cope with the increase in steam pressure and temperature at the main steam inlet. The tangential stress that occurs in the turbine rotor center hole in the low temperature region, especially the last stage blade in the rated rotation state, is about 0.95 in terms of stress ratio (working stress / allowable stress) for 26 inch long blades. In the case of 33.5 inch long wings, it is about 1.1, so it cannot be used.
[0113]
On the other hand, when 3.5% Ni-Cr-Mo-V steel is used, this rotor material is a material having toughness at a low temperature range, and at a lower temperature range than Cr-Mo-V steel. Since the tensile strength and proof stress are about 14% higher, even if a 33.5 inch long blade is used, the aforementioned stress ratio is about 0.96. When a 40-inch long blade is used, the stress ratio is 1.07 and cannot be used. In the high temperature range, the creep rupture stress is about 0.3 times that of Cr-Mo-V steel, resulting in insufficient high-temperature strength and cannot be used.
[0114]
In order to increase the output in this manner, a rotor material having excellent characteristics of Cr—Mo—V steel in a high temperature range and Ni—Cr—Mo—V steel in a low temperature range is necessary. When long blades of 30 inches or more and 40 inches are used, the stress ratio is 1.07 as described above, so the tensile strength is 88 kg / mm. ² The above materials are necessary. Furthermore, as a high and low pressure integrated steam turbine rotor material to which long blades of 30 inches or more are mounted, 538 ° C., 10 ^Five h Creep rupture strength 15kg / mm ² As described above, the impact absorption energy at room temperature is 2.5 kg-m (3 kg-m / cm) from the viewpoint of ensuring safety against destructive fracture on the low pressure side. ² ) The above materials are necessary.
[0115]
The steam turbine according to the present invention comprises 15 stages of blades 24 implanted in the high-low pressure integrated rotor shaft 23, and the steam passes through the steam control valve 25 and is steam at a high temperature and high pressure of 538 ° C. and 126 atg from the steam inlet 34. Flows into the high pressure section 30. The steam flows into the high pressure section 30 and exits at 367 ° C. and 38 atg. The steam is further reheated by the reheater 33 of the exhaust heat recovery boiler, heated to 538 ° C. and 35 atg, passes through the low pressure portion 31 of the rotor, and is discharged from the outlet 22 as steam of about 46 ° C. and 0.1 atg. Enter the condenser. 32 is a bearing.
[0116]
Since the high-low pressure-type rotor shaft 23 according to the present embodiment is exposed from steam of 538 ° C. to a temperature of 46 ° C., FATT 60 ° C. or lower, 538 ° C., 10 ^Five h Strength is 11kg / mm ² A forged steel of Ni—Cr—Mo—V low alloy steel having the above characteristics is used. The implanted portion of the blade 24 of the rotor shaft 23 has a disk shape, and is manufactured by being integrally cut from the rotor shaft 23. The length of the disk portion becomes longer as the blade length is shorter, and vibration is reduced.
[0117]
The rotor shaft 23 according to the present invention produced an ingot by remelting steel having the alloy composition shown in Table 4 above, hot forged to a diameter of 1.2 m, and heated and held at 950 ° C. for 10 hours. Water spray cooling was performed while rotating the shaft at 100 ° C./h at the center. Subsequently, tempering by heating and holding at 665 ° C. for 40 hours was performed. A test piece was cut out from the center of this rotor shaft, creep rupture test, V-notch impact test before and after heating (after heating at 500 ° C. for 3000 hours) (cross-sectional area of test piece 0.8 cm) ² ), A tensile test was performed.
[0118]
(1) High / low pressure-body rotor shaft
In this embodiment, Ni-Cr-Mo-V-based low alloy steel having the same composition and structure as the compressor rotor shaft material described above can be used as this member. In particular, (Mn / Ni) ratio of 0.12 or less or (Si + Mn) / Ni ratio of 0.18 or less is preferable, and (V + Mo) / (Ni + Cr) ratio of 0.45 to 0.70 is preferable. . Further, this low alloy steel can further contain one or more rare earth elements, Mg, Ca 0.04% or less, Hf, Zr 0.2% or less, W1% or less.
[0119]
(2) Blade (compressor, steam turbine)
The length of the three stages on the outlet side of the compressor and the three stages on the high temperature and high pressure side of the steam turbine is about 40 mm, and the materials are C0.20 to 0.30% by weight, Cr10 to 13%, Mo0.5 to 1.5%. , W 0.5-1.5%, V 0.1-0.3%, Si 0.5% or less, Mn 1% or less and the balance steel forged martensite steel.
[0120]
The intermediate pressure part of the steam turbine gradually increases in length toward the low pressure side. By weight, C0.05 to 0.15%, Mn 1% or less, Si 0.5% or less, Cr 10 to 13%, Mo 0.5% Hereinafter, it was constituted by forging of martensitic steel consisting of Ni 0.5% or less and the balance Fe.
[0121]
As the first stage of the compressor or the final stage of the steam turbine, about 33.5 inches in length, there are about 90 per round, and the materials are C0.08 to 0.15% by weight, Mn 1% or less, Si 0.5% or less, It was formed by forging martensitic steel consisting of Cr 10-13%, Ni 1.5-3.5%, Mo 1-2%, V 0.2-0.5%, N 0.02-0.08%, and the balance Fe. Further, an erosion-preventing shield plate made of a stellite plate is provided at the leading edge of the last stage by welding. In addition to the shield plate, a partial quenching process is performed. Furthermore, Ti blades containing 5 to 8% Al and 3 to 6% V are used for the first stage of the compressor or the last stage of 40 inches or more of the steam turbine.
[0122]
Four to five of these steam turbine blades are fixed at each stage by a shroud plate made of the same material by caulking a protruding tenon provided at the tip thereof.
[0123]
At 3000 rpm, the above-mentioned 12% Cr steel is used even at a length of 40 inches. At 3600 rpm, the Ti blades are used at 40 inches, but 12% Cr steel is used up to 33.5 inches.
[0124]
(3) A 13% Cr ferritic SUS material is used for the nozzle in the compressor, and a martensitic steel having the same composition as the moving blade is used for the stationary blade 27 of the steam turbine up to three stages of high pressure. In addition, the same thing as the above-mentioned medium pressure part moving blade material is used.
[0125]
(4) In the steam turbine casing 26, C 0.15 to 0.3% by weight, Si 0.5% or less, Mn 1% or less, Cr 1 to 2%, Mo 0.5 to 1.5%, V 0.05 to 0 Cr-Mo-V cast steel with 0.2% or less than 0.1% Ti is used. Reference numeral 28 denotes a generator, which can generate power of 100,000 to 200,000 kW. In this embodiment, the distance between the bearings 32 of the rotor shaft is about 520 cm, and the outer diameter of the final stage blade is 316 cm. The power generation capacity can be 100,000 kW. The length between the bearings is 0.52 m per 10,000 kW of power generation output.
[0126]
Further, in this embodiment, the outer diameter when the 40-inch blade is used as the final stage blade is 365 cm, and the ratio of the bearing to the outer diameter is 1.43. As a result, a power generation output of 200,000 kW is possible, and the distance between bearings per 10,000 kW is 0.26 m.
[0127]
The ratios of the rotor shaft blade implants to the length of these last stage blades are 1.70 for the 33.5 ″ blade and 1.71 for the 40 ″ blade.
[0128]
In this embodiment, the steam temperature can be applied at 566 ° C., and the pressure can be applied at 121, 169 and 224 atg.
[0129]
The plant configuration is a single shaft by combining six sets of power generation systems consisting of one each of gas turbine, exhaust heat recovery boiler, steam turbine, and generator, but there are multiple gas turbines and each exhaust heat. The present invention can also be applied to a multi-shaft combined cycle in which a recovery boiler is combined and electric power is generated by a single steam turbine using steam obtained thereby.
[0130]
In the case of a single shaft, the ratio of the power generation output is shared as 2/3 for the gas turbine and 1/3 for the steam turbine. Moreover, it can be set as 50,000 kW-200,000 kW as an output of a gas turbine, and the thing of the above-mentioned output is used for a steam turbine according to this.
[0131]
Thermal efficiency is 2 to 3% higher than conventional thermal power generation. Moreover, by reducing the number of operating gas turbines even at a partial load, it is possible to operate the operating equipment near the rated load with high thermal efficiency, so that the entire plant can maintain a high thermal efficiency of 46% or more. And CO for unit power generation ₂ The amount can be reduced and global warming can be reduced.
[0132]
Combined power generation consists of a combination of a gas turbine that is easy to start and stop in a short time and a small and simple steam turbine. Therefore, it is easy to adjust the output and is ideal as an intermediate load thermal power that responds quickly to changes in demand. It is.
[0133]
The reliability of gas turbines has increased dramatically due to recent technological developments, and the combined power plant is composed of a combination of small capacity machines. This is a highly reliable power supply that can keep the effects locally.
[0134]
Example 4
The alloy steel shown in Table 12 was melted in a basic electric furnace and sufficiently refined in a ladle. In ingot making, vacuum carbon deoxidation was performed simultaneously with vacuum casting. Next, it was forged hot (850 ° C. to 1200 ° C.) with a hydraulic press machine, divided into 6 parts, and finished to predetermined dimensions that could be molded into each disk hot. As shown in Table 13, the mechanical properties of each part of the rotor are as follows: Tensile strength at room temperature: 85 kg / mm ² Above, shock absorption energy at 20 ° C. 23 kg-m / cm ² From the above, it was proved that no embrittlement was observed and excellent properties were exhibited.
[0135]
It was proved that this rotor can be used as a rotor of a compressor for a gas turbine. Table 13 shows the material dimensions, heat treatment conditions, and mechanical properties of the center of a typical compressor rotor.
[0136]
Table 14 shows the impact value and FAAT after the embrittlement test for sample No. 5. It can be seen that neither test is very brittle.
[0137]
[Table 12]

[0138]
[Table 13]

[0139]
[Table 14]

[0140]
【The invention's effect】
According to the present invention, the number of parts can be reduced and the shape can be simplified as compared with a fully divided type disk, and as a result, high-temperature and high-compressed air can be sent as cooling of the combustor and the turbine section. The combustion gas temperature can be raised to 1400 ° C. or higher and the cooling can be efficiently performed, and the effect of improving the thermal efficiency of the gas turbine and achieving more efficient combined power generation can be obtained.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view of a gas turbine according to the present invention.
FIG. 2 is a perspective view of a compressor blade (blade) according to the present invention.
FIG. 3 is a perspective view of a compressor blade (blade) according to the present invention.
FIG. 4 is a heat treatment profile diagram of the step-cool method.
FIG. 5 is a configuration diagram showing a combined power generation system according to the present invention.
FIG. 6 is a partial cross-sectional view of a high and low pressure integrated steam turbine according to the present invention.
[Explanation of symbols]
2 ... turbine nozzle, 3 ... turbine blade, 4 ... turbine disk, 5 ... combustor, 6 ... split rotor for compressor, 7 ... compressor blade, 8 ... turbine spacer, 9, 10 ... bearing, 11 ... turbine stacking Bolt, 12 ... Compressor nozzle, 12 '... Compressor variable nozzle, 13 ... Liner, 14 ... Distant piece, 16 ... Wing, 17 ... Platform, 18 ... Implanted part, 19 ... Bolt, 23 ... High and low pressure integrated type Rotor shaft, 24 ... steam turbine blade, 26 ... casing, 27 ... steam turbine nozzle, 30 ... high pressure section, 31 ... low pressure section.

Claims (7)

In a gas turbine comprising: a compressor; and a turbine integrally connected to the compressor and rotated at high speed by combustion gas generated by the combustor,
The compressor has 12 or more stages of blades implanted in a rotor divided into a plurality of parts, and at least 6 stages from the first stage to one rotor are implanted with a plurality of stages of 3 stages or less. A high-temperature gas turbine characterized by In a gas turbine comprising: a compressor; and a turbine integrally connected to the compressor and rotated at high speed by combustion gas generated by the combustor,
The compressor has blades implanted in a plurality of divided rotors made of Ni-Cr-Mo-V based low alloy steel, and the blades are arranged in a plurality of stages from one stage to at least six stages. Has been planted,
At least the final stage of the rotor is made of the low alloy steel, and its 50% fracture surface transition temperature is 20 ° C. or less and 475 ° C., and the 10 ⁵ hour creep rupture strength is 30 kg / mm ² or more. Turbine. A compressor, in a gas turbine with a turbine rotating at a high speed by a combustion gas generated by the integrally connected to the combustor in the compressor,
The compressor has blades embedded in a plurality of divided rotors, and at least the final stage of the rotor is C0.15 to 0.40% by weight, Si 0.1% or less, and Mn 0.5%. Hereinafter, Ni 1.5 to 2.5%, Cr 0.8 to 2.5%, Mo 0.8 to 2.0%, V 0.1 to 0.35%, and one or more of Nb and Ta by weight are 0 %. . 01-0. comprises 1%, the balance being substantially Fe, hot gas turbines, characterized by consisting of Ni-Cr-Mo-V based low alloy steel having a total bainite structure. In a gas turbine comprising: a compressor; and a turbine integrally connected to the compressor and rotated at high speed by combustion gas generated by the combustor,
The compressor has blades implanted in a plurality of divided rotors made of Ni-Cr-Mo-V based low alloy steel, and the blades are arranged in a plurality of stages from one stage to at least six stages. Are planted, the diameter is the same,
The total length of the rotor between the blade implantations is 3.0 to 4.0 with respect to the maximum diameter of the rotor, or 3.7 to 4.7 with respect to the minimum diameter of the rotor. Turbine. In a gas turbine comprising a compressor and a turbine that is integrally connected to the compressor and that rotates at high speed with combustion gas generated by a combustor,
The compressor has 15 or more blades implanted in a divided rotor divided into 6 parts, 2 stages of blades are implanted from the first stage to the 8th stage, and 3 stages or more blades after the 9th stage A high-temperature gas turbine characterized by having a rotor in which is implanted. In a gas turbine comprising a compressor and a turbine that is integrally connected to the compressor and that rotates at high speed with combustion gas generated by a combustor,
The compressor has 15 or more stages of blades implanted in a split rotor, and the blades are embedded in the axial direction of the rotor independently from the first stage to at least the fifth stage except for the last stage rotor. The high temperature gas characterized in that the rotor having three or more stages of blades is structured such that the blades are implanted in a ring-shaped groove provided on the entire circumference of the rotor. Turbine. In a gas turbine comprising a compressor and a turbine that is integrally connected to the compressor and that rotates at high speed with combustion gas generated by a combustor,
The compressor has 15 or more blades implanted in a plurality of stages of at least three divided rotors, and the blades include at least one of the first stage and, if necessary, the second to fifth stages. A high-temperature gas turbine comprising a martensitic stainless steel except for a stage made of a Ti alloy and a stage after the second stage made of the Ti alloy.

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