JP2004197672A

JP2004197672A - Steam turbine system

Info

Publication number: JP2004197672A
Application number: JP2002368236A
Authority: JP
Inventors: Hiroshi Fujimoto; 洋藤本; Toshio Nishida; 利雄西田; Yukio Hiranaka; 幸男平中
Original assignee: Osaka Gas Co Ltd
Current assignee: Osaka Gas Co Ltd
Priority date: 2002-12-19
Filing date: 2002-12-19
Publication date: 2004-07-15
Anticipated expiration: 2022-12-19
Also published as: JP3871642B2

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the entry of air into a steam turbine during stopping operation. <P>SOLUTION: The steam turbine 8 is connected to a boiler 5 via a steam supply pipe 7 having a first on-off valve 6 and a condenser 12 is connected to the steam turbine 8 via a steam exhaust pipe 11 having a second on-off valve 10, and the condenser 12 and the boiler 5 are connected to each other via a pipe 13. A rotating shaft 14 of the steam turbine 8 is supported on a shaft sealing mechanism rotatably in a sealed condition. The steam exhaust pipe 11 is provided with a bypass pipe 17 in parallel to the second on-off valve 10 and the bypass pipe 17 is provided with a pressure control valve 18 for controlling pressure in the steam turbine 8. During stopping the operation of the steam turbine 8, the opening of the pressure control valve 18 is controlled so that pressure in the steam turbine 8 is set pressure higher than pressure outside the shaft sealing mechanism 15, preventing the entry of air into the steam turbine 8 through the shaft sealing mechanism 15. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、コジェネレーションシステムの発電装置駆動用のガスエンジンからの排熱などによりタービンを駆動する蒸気タービンシステムに関する。
【０００２】
【従来の技術】
このような蒸気タービンシステムとしては、従来、ガスエンジンから排出される高温排ガスをボイラに供給し、ボイラでアンモニア‐水系溶液の高温蒸気を発生させ、その高温蒸気で蒸気タービンを駆動し、蒸気タービンに連動連結した圧縮機などを駆動するように構成したものがあった（特許文献１、図１参照）。
【０００３】
上記システムにおいて、ガスエンジンの停止など、高温排ガスの発生が停止されて蒸気タービンの運転を停止したときに、蒸気タービンとボイラおよび復水器それぞれを接続する蒸気供給管および蒸気排出管それぞれに設けた開閉弁を閉じ、蒸気タービンの回転軸をシール状態で回転可能に支持する軸シール機構からアンモニアが漏洩することを防止するようにしている。
【０００４】
【特許文献１】
特開２００２−４８４２６号公報
【０００５】
【発明が解決しようとする課題】
しかしながら、従来例の場合、蒸気タービン内の蒸気が冷却されるに伴って蒸気タービンの内部の圧力が低下し、軸シール機構を通じて空気が流入してしまい、蒸気タービンの性能が低下する問題があった。
【０００６】
本発明は、このような事情に鑑みてなされたものであって、請求項１に係る発明の蒸気タービンシステムは、運転停止時における蒸気タービン内への空気の流入を防止できるようにすることを目的とし、また、請求項２に係る発明の蒸気タービンシステムは、運転停止後におけるアンモニアの漏洩を安価にして抑制できるようにすることを目的とする。
【０００７】
【課題を解決するための手段】
請求項１に係る発明は、上述のような目的を達成するために、
アンモニアと水の混合媒体を加熱して蒸気を発生するボイラと、
前記ボイラからの高圧蒸気で回転動力を得る蒸気タービンと、
前記蒸気タービンの回転軸をシール状態で回転可能に支持する軸シール機構と、
前記蒸気タービンから排出される蒸気を液化する復水器とを備えた蒸気タービンシステムにおいて、
前記ボイラと前記蒸気タービンとを接続する蒸気供給管に設けられて、蒸気の供給を停止する第１の開閉弁と、
前記蒸気タービンと前記復水器とを接続する蒸気排出管に設けられて、蒸気の排出を停止する第２の開閉弁と、
前記第１および第２の開閉弁の少なくとも一方と並列に設けられるバイパス配管と、
前記バイパス配管に設けられて前記蒸気タービン内の圧力を制御する圧力制御弁と、
前記軸シール機構の外側の圧力を測定する外部圧力計と、
前記蒸気タービン内の圧力を測定する圧力計と、
前記蒸気タービンの運転停止時に、前記圧力計で測定される前記蒸気タービン内の圧力が前記外部圧力計で測定される圧力よりも設定圧力だけ高くなるように前記圧力制御弁の開度を制御する圧力制御手段とを備えて構成する。
【０００８】
（作用・効果）
請求項１に係る発明の蒸気タービンシステムの構成によれば、運転停止に伴い、蒸気タービン内の圧力と軸シール機構の外側の圧力とを測定し、蒸気タービン内の圧力の方が設定圧力だけ高くなるように圧力制御弁の開度を制御し、蒸気タービン内に蒸気を導入することができる。
したがって、運転停止後に蒸気タービン内が冷却されても、その内部圧力が軸シール機構の外側の圧力より低下することを回避して、運転停止時における軸シール機構を通じての蒸気タービン内への空気の流入を防止でき、蒸気タービンの性能低下を防止できる。
【０００９】
請求項２に係る発明は、前述のような目的を達成するために、
請求項１に記載の蒸気タービンシステムにおいて、
蒸気タービンと並列に蒸気供給管に接続されるタービンバイパス配管と、
前記タービンバイパス配管に設けられて蒸気の流動を停止する第３の開閉弁と、
ボイラの停止に伴い、第２の開閉弁を閉じるとともに第３の開閉弁を開き、圧力計で測定される前記蒸気タービン内の圧力が外部圧力計で測定される圧力に第１の設定圧力分を加えた圧力よりも低くなったときまたは設定時間経過後に前記第３の開閉弁を閉じ、かつ、前記第３の開閉弁を閉じた後に、前記蒸気タービン内の圧力が外部圧力計で測定される圧力に第１の設定圧力分より小さい第２の設定圧力分を加えた圧力よりも低くなったときまたは設定時間経過後に第１の開閉弁を閉じる開閉弁制御手段とを備えて構成する。
【００１０】
（作用・効果）
請求項２に係る発明の蒸気タービンシステムの構成によれば、運転停止に伴い、第３の開閉弁を開いて蒸気タービン内の高圧蒸気をタービンバイパス配管を通じて逃がす。第３の開閉弁を閉じた後、蒸気タービン内の圧力が所定圧力分（第１の設定圧力分−第２の設定圧力分）低下するまでの間または設定時間が経過するまでの間は第１の開閉弁を開いておき、ボイラ内のアンモニア分を優先的に蒸発させ、ボイラ内のアンモニア分の濃度を低下し、ボイラの冷却に伴って、蒸気タービン内の圧力を早期に低下させることができる。
したがって、運転停止後に、蒸気タービンの内部圧力が軸シール機構の外側の圧力より設定以上に高い状態が継続する時間を大幅に短縮でき、運転停止後に軸シール機構を通じて漏洩するアンモニア量を減少でき、運転停止後にアンモニアの処理に要する費用とアンモニアの損失量を低減でき、運転停止後におけるアンモニアの漏洩を安価にして抑制できる。
【００１１】
【発明の実施の形態】
次に、本発明の実施例を図面に基づいて詳細に説明する。
【００１２】
図１は、本発明に係る蒸気タービンシステムの第１実施例を示す概略構成図であり、第１の発電機１を連動連結したガスエンジン２の排ガス配管３にＮＯｘを除去する脱硝装置４が付設されている。
【００１３】
排ガス配管３にボイラ５が接続され、アンモニアと水の混合媒体をガスエンジン２からの高温排ガスで加熱して蒸気を発生するように構成されている。
ボイラ５には、第１の開閉弁６を設けた蒸気供給管７を介して蒸気タービン８が接続され、蒸気タービン８に第２の発電機９が連動連結され、ボイラ５からの高圧蒸気で回転動力を得、ガスエンジン２からの排熱を利用して発電するように構成されている。
【００１４】
蒸気タービン８には、第２の開閉弁１０を設けた蒸気排出管１１を介して復水器１２が接続され、その復水器１２とボイラ５とが配管１３を介して接続され、蒸気タービン８から排出される蒸気を液化するように構成されている。
【００１５】
蒸気タービン８の回転軸１４が軸シール機構１５にシール状態で回転可能に支持され、軸シール機構１５の外側にアンモニア配管１６が接続され、そのアンモニア配管１６が脱硝装置４に接続され、蒸気タービン８の運転時に大きな圧力差に起因して軸シール機構１５から漏洩するアンモニアを脱硝用触媒に利用して処理するように構成されている。
【００１６】
蒸気排出管１１において、第２の開閉弁１０と並列にバイパス配管１７が設けられ、そのバイパス配管１７に、蒸気タービン８内の圧力を制御する圧力制御弁１８が設けられている。
【００１７】
アンモニア配管１６には、軸シール機構１５の外側の圧力を測定する外部圧力計１９が設けられ、蒸気タービン８には、その内部の圧力を測定する圧力計２０が設けられている。
【００１８】
また、ガスエンジン２の動力取出軸２１に回転停止を検出して運転停止信号を出力する回転計２２が設けられ、外部圧力計１９と圧力計２０と回転計２２とがコントローラ（ＣＰＵ）２３に接続され、コントローラ２３に第１および第２の開閉弁６，１０と圧力制御弁１８とが接続されている。
【００１９】
コントローラ２３には、図２の制御系のブロック図に示すように、運転停止判別手段２４と弁開閉手段２５と圧力制御手段２６とが備えられている。圧力制御手段２６は、加算手段２７と比較手段２８と開度算出手段２９とから構成されている。
【００２０】
運転停止判別手段２４では、回転計２２からの運転停止信号に応答して弁開閉手段２５に弁閉信号を出力するとともに、加算手段２７および比較手段２８それぞれに起動信号を出力するようになっている。弁開閉手段２５では、弁閉信号に応答して第１および第２の開閉弁６，１０に駆動信号を出力し、第１および第２の開閉弁６，１０を閉じるようになっている。
【００２１】
加算手段２７では、運転停止判別手段２４からの起動信号に応答して、外部圧力計１９で測定される圧力に設定圧力を加算し、その加算した圧力を目標圧力として比較手段２８に出力するようになっている。
【００２２】
比較手段２８では、運転停止判別手段２４からの起動信号に応答して、加算手段２７からの目標圧力と、圧力計２０で測定される蒸気タービン８内の圧力とを比較し、その圧力の差分を吸収するに足る開度を算出して圧力制御弁１８に駆動信号を出力し、算出開度分だけ圧力制御弁１８の開度を制御し、蒸気タービン８内の圧力が外部圧力計１９で測定される圧力よりも設定圧力だけ高くするように構成されている。
【００２３】
この第１実施例の構成によれば、蒸気タービン８の運転停止後に、第１および第２の開閉弁６，１０を閉じて蒸気タービン８内が冷却されても、その内部圧力が軸シール機構１５の外側の圧力より低下することを回避して、運転停止時における軸シール機構１５を通じての蒸気タービン８内への空気の流入を防止することができる。
【００２４】
上記第１実施例では、圧力制御弁１８を設けたバイパス配管１７を、第２の開閉弁１０と並列に設けているが、本発明としては、それに代えて、あるいは併設するように、第１の開閉弁６と並列に設けるようにしても良い。
また、第１および第２の開閉弁６，１０としては、それぞれ複数個設けるものであっても良い。すなわち、蒸気タービン８に対して別のボイラからの蒸気を供給する蒸気供給管が接続されるとともに、その蒸気供給管に開閉弁を設ける場合には、その開閉弁も第１の開閉弁に含む。同様に、蒸気タービン８に対して別の復水器に蒸気を排出する蒸気排出管が接続されるとともに、その蒸気排出管に開閉弁を設ける場合には、その開閉弁も第２の開閉弁に含む。
【００２５】
図３は、本発明に係る蒸気タービンシステムの第２実施例を示す概略構成図であり、第１実施例と異なるところは次の通りである。
すなわち、蒸気供給管７の第１の開閉弁６よりも上流側箇所に、蒸気タービン８と並列に、第３の開閉弁４１を設けたタービンバイパス配管４２が接続され、そのタービンバイパス配管４２が復水器１２に接続されている。
【００２６】
外部圧力計１９と圧力計２０と回転計２２とがコントローラ（ＣＰＵ）４３に接続され、コントローラ４３に第１、第２および第３の開閉弁６，１０，４１と圧力制御弁１８とが接続されている。
【００２７】
コントローラ４３には、図４の制御系のブロック図に示すように、圧力制御手段２６（図示せず。これは第１実施例と同じであり、構成および作用の説明は省略している）と、開閉弁制御手段４４が備えられている。
【００２８】
開閉弁制御手段４４には、運転停止判別手段４５、弁開閉手段４６、第１の加算手段４７、第１の比較手段４８、第１の弁閉判別手段４９、第２の加算手段５０、第２の比較手段５１および第２の弁閉判別手段５２が備えられている。
【００２９】
運転停止判別手段４５では、回転計２２からの運転停止信号に応答して弁開閉手段４６に弁開閉信号を出力するとともに、第１および第２の加算手段４７，４８、ならびに、第１および第２の比較手段５０，５１それぞれに起動信号を出力するようになっている。弁開閉手段４６では、弁開閉信号に応答して第１、第２および第３の開閉弁６，１０，４１に駆動信号を出力し、第１および第３の開閉弁６，４１を開くとともに第２の開閉弁１０を閉じるようになっている。
【００３０】
第１の加算手段４７では、運転停止判別手段４５からの起動信号に応答して、外部圧力計１９で測定される圧力に第１の設定圧力分を加算し、その加算した圧力を設定圧力として第１の比較手段４８に出力するようになっている。
【００３１】
第１の比較手段４８では、運転停止判別手段４５からの起動信号に応答して、第１の加算手段４７からの設定圧力と、圧力計２０で測定される蒸気タービン８内の圧力とを比較し、蒸気タービン８内の圧力が設定圧力になったときに弁閉信号を出力するようになっている。
第１の弁閉判別手段４９では、第１の比較手段４８からの弁閉信号に応答して、第３の開閉弁４１に駆動信号を出力し、第３の開閉弁４１を閉じるようになっている。
【００３２】
第２の加算手段５０では、運転停止判別手段４５からの起動信号に応答して、外部圧力計１９で測定される圧力に第１の設定圧力分より小さい第２の設定圧力分を加算し、その加算した圧力を設定圧力として第２の比較手段５１に出力するようになっている。
【００３３】
第２の比較手段５１では、運転停止判別手段４５からの起動信号に応答して、第２の加算手段５０からの設定圧力と、圧力計２０で測定される蒸気タービン８内の圧力とを比較し、蒸気タービン８内の圧力が設定圧力になったときに弁閉信号を出力するようになっている。
第２の弁閉判別手段５２では、第２の比較手段５１からの弁閉信号に応答して、第１の開閉弁６に駆動信号を出力し、第１の開閉弁６を閉じるようになっている。他の構成は、第１実施例と同じであり、同一図番を付すことにより、その説明は省略する。
【００３４】
この第２実施例の構成によれば、蒸気タービン８の運転停止に伴い、第３の開閉弁４１を開いて蒸気タービン８内の高圧蒸気をタービンバイパス配管４２を通じて逃がし、更に、第３の開閉弁４１を閉じた後、蒸気タービン８内の圧力が所定圧力分（第１の設定圧力分−第２の設定圧力分）低下するまでの間は第１の開閉弁６を開いておき、ボイラ５内のアンモニア分を優先的に蒸発させ、ボイラ５内のアンモニア分の濃度を低下して、ボイラ５の冷却に伴って、蒸気タービン８内の圧力を早期に低下させることができる。
【００３５】
上記第２実施例では、蒸気タービン８の運転停止後、圧力計２０で測定される蒸気タービン８内の圧力が外部圧力計１９で測定される圧力に第１の設定圧力分を加えた圧力よりも低くなったときに第３の開閉弁４１を閉じるように構成しているが、その第１の設定圧力分を加えた圧力よりも低くなる時間が推定できる場合には、その時間を設定時間として、設定時間経過後に第３の開閉弁４１を閉じるように構成しても良い。
【００３６】
また、第３の開閉弁４１を閉じた後に、蒸気タービン８内の圧力が外部圧力計１９で測定される圧力に第１の設定圧力分より小さい第２の設定圧力分を加えた圧力よりも低くなったときに第１の開閉弁６を閉じるように構成しているが、その第１の設定圧力分を加えた圧力よりも低くなる時間が推定できる場合には、その時間を設定時間として、設定時間経過後に第１の開閉弁６を閉じるように構成しても良い。
【００３７】
上記第２実施例において、第３の開閉弁４１をリリーフ弁で構成し、そのリリーフ圧力を、蒸気タービン８の運転時には、閉じ状態を維持するように高圧に設定しておき、蒸気タービン８の運転停止に伴い、外気圧よりやや高い圧力、すなわち、実質的に、蒸気タービン８内の圧力が外部圧力計１９で測定される圧力に第１の設定圧力分を加えた圧力にリリーフ圧力を切り替えるように構成しても良い。
【００３８】
【発明の効果】
以上の説明から明らかなように、請求項１に係る発明の蒸気タービンシステムによれば、運転停止に伴い、蒸気タービン内の圧力と軸シール機構の外側の圧力とを測定し、蒸気タービン内の圧力の方が設定圧力だけ高くなるように圧力制御弁の開度を制御し、蒸気タービン内に蒸気を導入することができるから、運転停止後に蒸気タービン内が冷却されても、その内部圧力が軸シール機構の外側の圧力より低下することを回避して、運転停止時における軸シール機構を通じての蒸気タービン内への空気の流入を防止でき、蒸気タービンの性能低下を防止できる。
【図面の簡単な説明】
【図１】本発明に係る蒸気タービンシステムの第１実施例を示す概略構成図である。
【図２】第１実施例の制御系を示すブロック図である。
【図３】本発明に係る蒸気タービンシステムの第２実施例を示す概略構成図である。
【図４】第２実施例の制御系を示すブロック図である。
【符号の説明】
５…ボイラ
６…第１の開閉弁
７…蒸気供給管
８…蒸気タービン
１０…第２の開閉弁
１１…蒸気排出管
１２…復水器
１４…回転軸
１５…軸シール機構
１７…バイパス配管
１８…圧力制御弁
１９…外部圧力計
２０…圧力計
２６…圧力制御手段
４１…第３の開閉弁
４２…タービンバイパス配管
４４…開閉弁制御手段[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a steam turbine system that drives a turbine by exhaust heat from a gas engine for driving a power generation device of a cogeneration system.
[0002]
[Prior art]
Conventionally, such a steam turbine system conventionally supplies high-temperature exhaust gas discharged from a gas engine to a boiler, generates high-temperature steam of an ammonia-water-based solution in the boiler, and drives the steam turbine with the high-temperature steam. There has been a device configured to drive a compressor or the like interlockingly connected to the device (see Patent Document 1, FIG. 1).
[0003]
In the above system, when the generation of high-temperature exhaust gas is stopped, such as when the gas engine is stopped, and the operation of the steam turbine is stopped, a steam supply pipe and a steam discharge pipe are provided for connecting the steam turbine, the boiler, and the condenser, respectively. The on-off valve is closed to prevent ammonia from leaking from a shaft seal mechanism that rotatably supports the rotating shaft of the steam turbine in a sealed state.
[0004]
[Patent Document 1]
JP-A-2002-48426
[Problems to be solved by the invention]
However, in the case of the conventional example, there is a problem that as the steam in the steam turbine is cooled, the pressure inside the steam turbine decreases, air flows in through the shaft seal mechanism, and the performance of the steam turbine decreases. Was.
[0006]
The present invention has been made in view of such circumstances, and the steam turbine system according to the first aspect of the present invention is configured to prevent air from flowing into the steam turbine when the operation is stopped. It is another object of the present invention to provide a steam turbine system according to the second aspect of the present invention, which can suppress the leakage of ammonia after the operation is stopped at a low cost.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 achieves the above object by
A boiler that generates steam by heating a mixed medium of ammonia and water;
A steam turbine that obtains rotational power with high-pressure steam from the boiler,
A shaft sealing mechanism that rotatably supports the rotating shaft of the steam turbine in a sealed state,
A steam turbine system comprising: a condenser for liquefying steam discharged from the steam turbine;
A first on-off valve provided on a steam supply pipe connecting the boiler and the steam turbine to stop supply of steam;
A second on-off valve that is provided on a steam discharge pipe that connects the steam turbine and the condenser and stops discharging steam;
A bypass pipe provided in parallel with at least one of the first and second on-off valves;
A pressure control valve provided in the bypass pipe to control a pressure in the steam turbine;
An external pressure gauge that measures the pressure outside the shaft seal mechanism,
A pressure gauge for measuring the pressure in the steam turbine,
When the operation of the steam turbine is stopped, the opening of the pressure control valve is controlled so that the pressure in the steam turbine measured by the pressure gauge becomes higher than the pressure measured by the external pressure gauge by a set pressure. And pressure control means.
[0008]
(Action / Effect)
According to the configuration of the steam turbine system according to the first aspect of the present invention, the pressure inside the steam turbine and the pressure outside the shaft seal mechanism are measured with the shutdown, and the pressure inside the steam turbine is only the set pressure. The opening of the pressure control valve is controlled so as to be higher, and steam can be introduced into the steam turbine.
Therefore, even if the inside of the steam turbine is cooled after the shutdown, it is possible to prevent the internal pressure from dropping below the pressure outside the shaft seal mechanism, and to prevent the air from flowing into the steam turbine through the shaft seal mechanism during the shutdown. Inflow can be prevented, and performance degradation of the steam turbine can be prevented.
[0009]
The invention according to claim 2 is to achieve the above object,
The steam turbine system according to claim 1,
A turbine bypass pipe connected to the steam supply pipe in parallel with the steam turbine,
A third on-off valve provided in the turbine bypass pipe to stop the flow of steam;
With the stop of the boiler, the second on-off valve is closed and the third on-off valve is opened, and the pressure in the steam turbine measured by the pressure gauge is reduced by the first set pressure to the pressure measured by the external pressure gauge. The third on-off valve is closed when the pressure becomes lower than the pressure obtained by adding the pressure, or after a lapse of a set time, and after the third on-off valve is closed, the pressure in the steam turbine is measured by an external pressure gauge. Opening / closing valve control means for closing the first opening / closing valve when the pressure becomes lower than a pressure obtained by adding a second set pressure smaller than the first set pressure to the predetermined pressure or after a lapse of a set time.
[0010]
(Action / Effect)
According to the configuration of the steam turbine system according to the second aspect of the present invention, when the operation is stopped, the third on-off valve is opened to allow high-pressure steam in the steam turbine to escape through the turbine bypass pipe. After the third on-off valve is closed, the pressure in the steam turbine is reduced by a predetermined pressure (a first set pressure minus a second set pressure) or until a set time elapses. (1) Opening the on-off valve, preferentially evaporating the ammonia in the boiler, lowering the concentration of ammonia in the boiler, and reducing the pressure in the steam turbine early with cooling of the boiler Can be.
Therefore, after the operation is stopped, the time during which the internal pressure of the steam turbine is higher than the pressure outside the shaft seal mechanism by a predetermined amount or more can be greatly reduced, and the amount of ammonia leaking through the shaft seal mechanism after the operation is stopped can be reduced. The cost required for the treatment of ammonia and the amount of ammonia loss after the operation is stopped can be reduced, and the leakage of ammonia after the operation is stopped can be reduced and suppressed.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings.
[0012]
FIG. 1 is a schematic configuration diagram showing a first embodiment of a steam turbine system according to the present invention. A denitration device 4 for removing NOx from an exhaust gas pipe 3 of a gas engine 2 in which a first generator 1 is interlocked is provided. It is attached.
[0013]
A boiler 5 is connected to the exhaust gas pipe 3, and is configured to generate steam by heating a mixed medium of ammonia and water with high-temperature exhaust gas from the gas engine 2.
A steam turbine 8 is connected to the boiler 5 through a steam supply pipe 7 provided with a first opening / closing valve 6, and a second generator 9 is connected to the steam turbine 8 in an interlocked manner. It is configured to obtain rotational power and generate electric power using exhaust heat from the gas engine 2.
[0014]
A condenser 12 is connected to the steam turbine 8 via a steam discharge pipe 11 provided with a second on-off valve 10, and the condenser 12 and the boiler 5 are connected via a pipe 13. It is configured to liquefy the steam discharged from the fuel cell 8.
[0015]
The rotary shaft 14 of the steam turbine 8 is rotatably supported in a sealed state by a shaft seal mechanism 15, an ammonia pipe 16 is connected to the outside of the shaft seal mechanism 15, and the ammonia pipe 16 is connected to the denitration device 4, In operation 8, the ammonia leaking from the shaft seal mechanism 15 due to a large pressure difference is used as a denitration catalyst for processing.
[0016]
In the steam discharge pipe 11, a bypass pipe 17 is provided in parallel with the second on-off valve 10, and a pressure control valve 18 for controlling the pressure in the steam turbine 8 is provided in the bypass pipe 17.
[0017]
The ammonia pipe 16 is provided with an external pressure gauge 19 for measuring the pressure outside the shaft seal mechanism 15, and the steam turbine 8 is provided with a pressure gauge 20 for measuring the internal pressure.
[0018]
A tachometer 22 for detecting a rotation stop and outputting an operation stop signal is provided on a power take-off shaft 21 of the gas engine 2, and the external pressure gauge 19, the pressure gauge 20 and the tachometer 22 are transmitted to a controller (CPU) 23. The controller 23 is connected to the first and second on-off valves 6 and 10 and the pressure control valve 18.
[0019]
As shown in the block diagram of the control system in FIG. 2, the controller 23 includes an operation stop determination unit 24, a valve opening / closing unit 25, and a pressure control unit 26. The pressure control means 26 includes an adding means 27, a comparing means 28, and an opening calculating means 29.
[0020]
The operation stop judging means 24 outputs a valve closing signal to the valve opening / closing means 25 in response to the operation stop signal from the tachometer 22, and outputs a start signal to each of the adding means 27 and the comparing means 28. I have. In the valve opening / closing means 25, a drive signal is output to the first and second opening / closing valves 6, 10 in response to the valve closing signal, and the first and second opening / closing valves 6, 10 are closed.
[0021]
The adding means 27 adds the set pressure to the pressure measured by the external pressure gauge 19 in response to the start signal from the operation stop determining means 24, and outputs the added pressure to the comparing means 28 as a target pressure. It has become.
[0022]
The comparing means 28 compares the target pressure from the adding means 27 with the pressure in the steam turbine 8 measured by the pressure gauge 20 in response to the start signal from the operation stop judging means 24, and calculates a difference between the pressures. An opening degree sufficient to absorb the pressure is calculated, a drive signal is output to the pressure control valve 18, the opening degree of the pressure control valve 18 is controlled by the calculated opening degree, and the pressure in the steam turbine 8 is measured by the external pressure gauge 19. The pressure is set to be higher than the measured pressure by a set pressure.
[0023]
According to the configuration of the first embodiment, even after the operation of the steam turbine 8 is stopped and the inside of the steam turbine 8 is cooled by closing the first and second on-off valves 6 and 10, the internal pressure is reduced by the shaft seal mechanism. It is possible to prevent the pressure from dropping below the pressure outside of the air turbine 15 and to prevent air from flowing into the steam turbine 8 through the shaft seal mechanism 15 when the operation is stopped.
[0024]
In the first embodiment, the bypass pipe 17 provided with the pressure control valve 18 is provided in parallel with the second on-off valve 10. However, the present invention provides a May be provided in parallel with the on-off valve 6.
Further, a plurality of first and second on-off valves 6 and 10 may be provided respectively. That is, when a steam supply pipe for supplying steam from another boiler is connected to the steam turbine 8 and an on-off valve is provided in the steam supply pipe, the on-off valve is also included in the first on-off valve. . Similarly, when a steam discharge pipe for discharging steam to another condenser is connected to the steam turbine 8 and an on-off valve is provided in the steam discharge pipe, the on-off valve is also a second on-off valve. Included.
[0025]
FIG. 3 is a schematic configuration diagram showing a second embodiment of the steam turbine system according to the present invention. The difference from the first embodiment is as follows.
That is, a turbine bypass pipe 42 provided with a third on-off valve 41 is connected in parallel with the steam turbine 8 at a location on the steam supply pipe 7 upstream of the first on-off valve 6, and the turbine bypass pipe 42 is It is connected to the condenser 12.
[0026]
The external pressure gauge 19, the pressure gauge 20, and the tachometer 22 are connected to a controller (CPU) 43, and the controller 43 is connected to the first, second and third opening / closing valves 6, 10, 41 and the pressure control valve 18. Have been.
[0027]
As shown in the block diagram of the control system in FIG. 4, the controller 43 includes a pressure control means 26 (not shown. This is the same as in the first embodiment, and the description of the configuration and operation is omitted). , An opening / closing valve control means 44 is provided.
[0028]
The open / close valve control means 44 includes an operation stop determination means 45, a valve open / close means 46, a first addition means 47, a first comparison means 48, a first valve close determination means 49, a second addition means 50, A second comparing means 51 and a second valve closing determining means 52 are provided.
[0029]
The operation stop judging means 45 outputs a valve opening / closing signal to the valve opening / closing means 46 in response to the operation stop signal from the tachometer 22, and includes first and second adding means 47 and 48, and first and second An activation signal is output to each of the second comparison means 50 and 51. The valve opening / closing means 46 outputs a drive signal to the first, second, and third opening / closing valves 6, 10, 41 in response to the valve opening / closing signal, and opens the first and third opening / closing valves 6, 41. The second on-off valve 10 is closed.
[0030]
The first adding means 47 adds a first set pressure to the pressure measured by the external pressure gauge 19 in response to a start signal from the operation stop determining means 45, and uses the added pressure as a set pressure. The data is output to the first comparing means 48.
[0031]
The first comparing means 48 compares the set pressure from the first adding means 47 with the pressure in the steam turbine 8 measured by the pressure gauge 20 in response to the start signal from the operation stop judging means 45. Then, a valve closing signal is output when the pressure in the steam turbine 8 reaches the set pressure.
The first valve closing determination means 49 outputs a drive signal to the third opening / closing valve 41 in response to the valve closing signal from the first comparing means 48, and closes the third opening / closing valve 41. ing.
[0032]
The second adding means 50 adds a second set pressure smaller than the first set pressure to the pressure measured by the external pressure gauge 19 in response to the start signal from the operation stop determination means 45, The added pressure is output to the second comparing means 51 as a set pressure.
[0033]
The second comparing means 51 compares the set pressure from the second adding means 50 with the pressure in the steam turbine 8 measured by the pressure gauge 20 in response to the start signal from the operation stop judging means 45. Then, a valve closing signal is output when the pressure in the steam turbine 8 reaches the set pressure.
The second valve closing determining means 52 outputs a drive signal to the first on-off valve 6 in response to the valve closing signal from the second comparing means 51, and closes the first on-off valve 6. ing. The other configuration is the same as that of the first embodiment, and the description is omitted by attaching the same figure number.
[0034]
According to the configuration of the second embodiment, when the operation of the steam turbine 8 is stopped, the third on-off valve 41 is opened to allow high-pressure steam in the steam turbine 8 to escape through the turbine bypass pipe 42, After the valve 41 is closed, the first on-off valve 6 is kept open until the pressure in the steam turbine 8 decreases by a predetermined pressure (the first set pressure minus the second set pressure), and the boiler is opened. The ammonia content in the steam turbine 8 is preferentially evaporated, the ammonia content in the boiler 5 is reduced, and the pressure in the steam turbine 8 can be reduced at an early stage as the boiler 5 is cooled.
[0035]
In the second embodiment, after the operation of the steam turbine 8 is stopped, the pressure in the steam turbine 8 measured by the pressure gauge 20 is made smaller than the pressure obtained by adding the first set pressure to the pressure measured by the external pressure gauge 19. The third opening / closing valve 41 is configured to be closed when the pressure becomes low. However, if it is possible to estimate a time that becomes lower than the pressure obtained by adding the first set pressure, the time is set to the set time. Alternatively, the third on-off valve 41 may be closed after a set time has elapsed.
[0036]
After the third on-off valve 41 is closed, the pressure in the steam turbine 8 is lower than the pressure obtained by adding a second set pressure smaller than the first set pressure to the pressure measured by the external pressure gauge 19. The first opening / closing valve 6 is configured to be closed when the pressure becomes low. However, if a time that is lower than the pressure obtained by adding the first set pressure can be estimated, the time is set as the set time. Alternatively, the first opening / closing valve 6 may be closed after a set time has elapsed.
[0037]
In the second embodiment, the third on-off valve 41 is constituted by a relief valve, and its relief pressure is set to a high pressure so as to maintain a closed state during operation of the steam turbine 8. With the stoppage of operation, the relief pressure is switched to a pressure slightly higher than the external pressure, that is, a pressure obtained by adding a first set pressure to the pressure measured by the external pressure gauge 19 in the steam turbine 8. You may comprise so that it may be.
[0038]
【The invention's effect】
As is clear from the above description, according to the steam turbine system of the first aspect of the present invention, the pressure inside the steam turbine and the pressure outside the shaft seal mechanism are measured when the operation is stopped, and the inside of the steam turbine is measured. The opening of the pressure control valve can be controlled so that the pressure becomes higher by the set pressure, and steam can be introduced into the steam turbine. By preventing the pressure from dropping below the pressure outside the shaft seal mechanism, it is possible to prevent air from flowing into the steam turbine through the shaft seal mechanism when operation is stopped, and prevent performance degradation of the steam turbine.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a first embodiment of a steam turbine system according to the present invention.
FIG. 2 is a block diagram showing a control system of the first embodiment.
FIG. 3 is a schematic configuration diagram showing a second embodiment of the steam turbine system according to the present invention.
FIG. 4 is a block diagram illustrating a control system according to a second embodiment.
[Explanation of symbols]
5 Boiler 6 First open / close valve 7 Steam supply pipe 8 Steam turbine 10 Second open / close valve 11 Steam discharge pipe 12 Condenser 14 Rotary shaft 15 Shaft seal mechanism 17 Bypass pipe 18 ... pressure control valve 19 ... external pressure gauge 20 ... pressure gauge 26 ... pressure control means 41 ... third on-off valve 42 ... turbine bypass pipe 44 ... on-off valve control means

Claims

A boiler that generates steam by heating a mixed medium of ammonia and water;
A steam turbine that obtains rotational power with high-pressure steam from the boiler,
A shaft sealing mechanism that rotatably supports the rotating shaft of the steam turbine in a sealed state,
A steam turbine system comprising: a condenser for liquefying steam discharged from the steam turbine;
A first on-off valve provided on a steam supply pipe connecting the boiler and the steam turbine to stop supply of steam;
A second on-off valve that is provided on a steam discharge pipe that connects the steam turbine and the condenser and stops discharging steam;
A bypass pipe provided in parallel with at least one of the first and second on-off valves;
A pressure control valve provided in the bypass pipe to control a pressure in the steam turbine;
An external pressure gauge that measures the pressure outside the shaft seal mechanism,
A pressure gauge for measuring the pressure in the steam turbine,
When the operation of the steam turbine is stopped, the opening of the pressure control valve is controlled so that the pressure in the steam turbine measured by the pressure gauge becomes higher than the pressure measured by the external pressure gauge by a set pressure. Pressure control means;
A steam turbine system comprising:

The steam turbine system according to claim 1,
A turbine bypass pipe connected to the steam supply pipe in parallel with the steam turbine,
A third on-off valve provided in the turbine bypass pipe to stop the flow of steam;
With the stop of the boiler, the second on-off valve is closed and the third on-off valve is opened, and the pressure in the steam turbine measured by the pressure gauge is reduced by the first set pressure to the pressure measured by the external pressure gauge. The third on-off valve is closed when the pressure becomes lower than the pressure obtained by adding the pressure, or after a lapse of a set time, and after the third on-off valve is closed, the pressure in the steam turbine is measured by an external pressure gauge. Opening / closing valve control means for closing the first opening / closing valve when the pressure becomes lower than a pressure obtained by adding a second set pressure smaller than the first set pressure to the pressure or after a lapse of a set time;
A steam turbine system.