JP3604886B2 - Pressurized fluidized bed combined cycle power plant and power plant - Google Patents

Pressurized fluidized bed combined cycle power plant and power plant Download PDF

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JP3604886B2
JP3604886B2 JP32262997A JP32262997A JP3604886B2 JP 3604886 B2 JP3604886 B2 JP 3604886B2 JP 32262997 A JP32262997 A JP 32262997A JP 32262997 A JP32262997 A JP 32262997A JP 3604886 B2 JP3604886 B2 JP 3604886B2
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exhaust gas
pressurized fluidized
water supply
deaerator
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JPH11159305A (en
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行正 吉成
健 上野
均 石川
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Hitachi Ltd
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E20/00—Combustion technologies with mitigation potential
    • Y02E20/16—Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT]

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Description

【０００１】
【発明の属する技術分野】
本発明は、加圧流動床ボイラとガスタービンと蒸気タービンとを備えている加圧流動床複合発電プラント、及び発電プラントに関するものである。
【０００２】
【従来の技術】
従来一般に採用されているこの種の加圧流動床複合発電プラントは、図８にその概略系統が示されているように、復水ポンプ１２と脱気器１７の間に低圧給水加熱器１４，排ガス・灰クーラ３０および排カス熱交換器６が並列に設置され、そして低圧給水加熱器１４，排ガス・灰クーラ３０および排カス熱交換器６の給水量は、その入口または出口に設けられている流量調節弁により制御され、また、脱気器１７への給水は、復水ポンプ１２出口に設置された脱気器水位調節弁１３により制御されるようになっているのが普通である。
【０００３】
なお、この種加圧流動床複合発電プラントに関連するものとしては、例えば特開平６−１８５７０４号公報が挙げられる。
【０００４】
【発明が解決しようとする課題】
このように形成されている加圧流動床複合発電プラントであると、プラントの緊急停止時において、給水量を急速に減少させると脱気器水位調節弁１３の応答遅れ、脱気器１７内の蒸気凝縮および脱気器内給水の落水により脱気器水位が上昇し脱気器水位調節弁１３が脱気器水位計１８から信号により全閉となり脱気器１７への給水が停止される。
【０００５】
一方、排ガス・灰クーラ３０および排ガス熱交換器６は、ガス側および灰側からの入熱により給水が加熱され、このため排ガス・灰クーラ３０および排カス熱交換器６廻りの給水がフラッシュ（水⇒蒸気）し、排ガス・灰クーラ３０および排カス熱交換器６などの機器および配管弁を損傷することが容易に推定される。
【０００６】
またプラント起動停止時に少量の給水をボイラへ供給すると脱気器水位調節弁１３の連続制御が不可能となり脱気器１７への給水が停止（ＯＮ−ＯＦＦ制御）される可能性があり緊急停止時と同様の事象が発生することが考えられる。なお、前述した特開平６−１８５７０４号公報に記載のものでは、緊急停止時および起動停止時における配慮に欠け、ガス側および灰側からの入熱による排ガス・灰クーラ３０および排カス熱交換器６廻りの給水フラッシュを防止することは不可能であった。
【０００７】
本発明はこれに鑑みなされたもので、その目的とするところは、プラントの起動停止時および緊急停止時に排ガス熱交換器廻りで発生するフラッシュを充分防止し、安定運転の確保、機器保護および信頼性の向上を図ることが可能なこの主の加圧流動床複合発電プラント、及び発電プラントを提供することにある。
【０００８】
【課題を解決するための手段】
すなわち本発明は、蒸気を発生させる加圧流動床ボイラと、この加圧流動床ボイラで発生した蒸気により駆動される蒸気タービンと、前記加圧流動床ボイラからの燃焼排ガスにより駆動されるガスタービンと、前記蒸気タービンの復水器から前記加圧流動床ボイラへ給水する給水系統とを備え、前記給水系統に、ガスタービン排ガスと熱交換を行い給水を加熱する排ガス熱交換器と、該排ガス熱交換器から供給される給水を脱気する脱気器が設けられている加圧流動床複合発電プラントにおいて、前記給水系統に、前記脱気器または脱気器出口側の給水を、前記排ガス熱交換器内の給水の置換水として排ガス熱交換器に供給する置換水供給系統を設けるようになし所期の目的を達成するようにしたものである。
【０００９】
また本発明は、蒸気を発生させる加圧流動床ボイラと、この加圧流動床ボイラで発生した蒸気により駆動される蒸気タービンと、前記加圧流動床ボイラからの燃焼排ガスにより駆動されるガスタービンと、前記蒸気タービンの復水器から前記加圧流動床ボイラへ給水する給水系統とを備え、前記給水系統に、ガスタービン排ガスと熱交換を行い給水を加熱する排ガス熱交換器と、該排ガス熱交換器から供給される給水を脱気する脱気器が設けられている加圧流動床複合発電プラントにおいて、前記給水系統に、前記排ガス熱交換器の出口側の給水を前記復水器へ供給する給水循環系統を設けるようにしたものである。
【００１０】
またこの場合、前記給水循環系統に、緊急停止時および起動停止時に排ガス熱交換器出口から復水器への置換水を規定量に制御する調節弁，流量計および温度計を設けるようにしたものである。
【００１１】
また本発明は、蒸気を発生させる加圧流動床ボイラと、この加圧流動床ボイラで発生した蒸気により駆動される蒸気タービンと、前記加圧流動床ボイラからの排ガスにより駆動されるガスタービンと、前記蒸気タービンの復水器から前記加圧流動床ボイラへ給水する給水系統を備え、前記給水系統に、給水を加熱する排ガス熱交換器，給水加熱器および脱気器が設けられている加圧流動床複合発電プラントにおいて、前記給水系統に、緊急停止または起動停止時に前記脱気器の水位制御装置からの信号により脱気器レベル調節弁を介して前記排ガス熱交換器へ置換水を供給する置換水供給系統を設けるとともに、この置換水供給系統に、供給置換水量を規定量に制御する調節弁を設けるようにしたものである。
【００１２】
また本発明は、蒸気を発生させる加圧流動床ボイラと、この加圧流動床ボイラで発生した蒸気により駆動される蒸気タービンと、前記加圧流動床ボイラからの燃焼排ガスにより駆動されるガスタービンと、前記蒸気タービンの復水器から前記加圧流動床ボイラへ給水する給水系統とを備え、前記給水系統に、給水を加熱する排ガス熱交換器，給水加熱器および脱気器が設けられている加圧流動床複合発電プラントにおいて、前記給水系統に、緊急停止時および起動停止時に排ガス・灰ク−ラ出口から排ガス熱交換器への置換水を供給する置換水供給系統を設けるとともに、この置換水供給系統に、供給置換水量を規定量に制御するため調節弁および流量計を設けるようにしたものである。
また本発明は、蒸気を発生させるボイラと、該ボイラで発生した蒸気により駆動される蒸気タービンと、燃焼ガスにより駆動されるガスタービンと、前記蒸気タービンで仕事をした蒸気を復水する復水器と、該復水器から前記ボイラへ給水する給水系統とを備え、前記給水系統は、前記復水器から供給される給水と前記ガスタービンの排ガスとを熱交換して前記給水を加熱する排ガス熱交換器と、該排ガス熱交換器から供給される給水を脱気する脱気器とを有する発電プラントにおいて、前記給水系統に、前記脱気器または脱気器出口側の給水を、前記排ガス熱交換器へ供給する給水供給系統を設けるようにしたものである。
【００１３】
すなわちこのように形成された加圧流動床複合発電プラントであると、排ガス熱交換器内の給水を置換するため脱気器の給水を脱気器出口から排ガス熱交換器へ供給するための供給系統が設けられていることから、緊急停止時および起動停止時に脱気器水位調節弁が全閉した場合であっても、脱気器の給水を脱気器から排ガス熱交換器入口管へ供給することが可能となり、ガス側および灰側からの入熱による排ガス熱交換器廻りの温度上昇を緩和することができ安定した運転状態を確保することが可能となるのである。
【００１４】
また、排ガス熱交換器の給水を置換するため、排ガス・灰クーラ出口の給水を排ガス・灰クーラ出口管から排ガス熱交換器へ供給するための系統が設けられていることから、緊急停止時および起動停止時に脱気器水位調節弁が全閉した場合でも排ガス・灰クーラ出口の給水を排ガス・灰クーラ出口管から排ガス熱交換器へ供給することが可能となるため、ガス側および灰側からの入熱による排ガス熱交換器廻りの温度上昇を緩和することがき安定した運転状態を確保することが可能となる。
【００１５】
また、排ガス熱交換器出口の給水を復水器へ供給するための系統が設けられていることから、緊急停止時および起動停止時に少量の給水を加圧流動床ボイラへ供給する場合でも排ガス熱交換器出口の給水を復水器へ供給することにより、脱気器水位調節弁の通水量が増加するため脱気器水位調節弁の連続制御が可能性となる。このため、排ガス熱交換器の給水量が増加し、ガス側および灰側からの入熱による排ガス熱交換器廻りの温度上昇を緩和することができ安定した運転状態を確保することが可能となる。
【００１６】
またもう一つの発明は、脱気器水位調節弁の制御を脱気器水位装置（給水流量、給水ダンプ流量、脱気器水位と緊急停止モード）からの信号等により先行制御し排ガス熱交換器への給水を復水ポンプ出口より供給したもので、これにより、緊急停止時および起動停止時に少量の給水をボイラへ供給すると場合でも復水ポンプ出口の給水を脱気器水位調節弁を介し排ガス熱交換器へ給水することが可能となるため、ガス側および灰側からの入熱による排ガス熱交換器廻りの温度上昇を緩和することがき安定した運転状態を確保することが可能となる。
【００１７】
また、本発明は、給水循環ポンプ出口の配管部に、給水量を調節するための給水循環ポンプ出口流量計と給水循環ポンプ出口流量調節弁が設けられていることから、緊急停止時および起動停止時の脱気器から排ガス熱交換器への給水量を規定値に調節することが可能となり、ガス側および灰側からの入熱による排ガス熱交換器廻りの温度上昇を緩和することがき安定した運転状態を確保することが可能となる。
【００１８】
また、排ガス熱交換器出口から復水器への給水量を調節するための給水ダンプ流量計、給水ダンプ流量調節弁、脱気器圧力計、復水ダンプ流量計、および排ガス熱交換器温度計が設けられていることから、緊急停止時および起動停止時に少量の給水をボイラへ供給すると場合でも排ガス熱交換器出口の給水を復水器へ供給することにより、脱気器水位調節弁の通水量が増加するため脱気器水位調節弁の連続制御が可能性となる。このため、排ガス熱交換器の給水量が増加し、ガス側および灰側からの入熱による排ガス熱交換器廻りの温度上昇を緩和することがき安定した運転状態を確保することが可能となるのである。
【００１９】
【発明の実施の形態】
以下図示した実施例に基づいて本発明を詳細に説明する。図１にはその加圧流動床複合発電プラントの系統が示されている。図中４がガスタービンであり、１がガスタービン圧縮機、２が加圧流動床ボイラ、８が高圧蒸気タービン、９が再熱蒸気タービンである。なお、５はガスタービン発電機であり、１０は蒸気タービン発電機、７は排ガス用の煙突である。
【００２０】
まず、この図に示されているように、ガスタービン圧縮機１に導入された空気は、高圧空気となって加圧流動床ボイラ２へ導入される。そしてこの導入された高圧空気は、加圧流動床ボイラ内で燃料供給系統３から供給される燃料とともに燃焼し、高温・高圧の燃料ガスとなり、ガスタービン４にて膨張し仕事をする。ガスタービン４はガスタービン発電機５を回転させ電気出力を得る。その後、この仕事を終えたガスタービン排ガスは、排ガス熱交換器６で給水と熱交換し、やがて煙突７より大気へ放出される。
【００２１】
一方、加圧流動床ボイラ２に供給された高温給水は、加圧流動床ボイラ２で加熱され高温高圧蒸気となって高圧蒸気タービン８へ送られ高圧蒸気タービン８を回転駆動させる。さらに膨張した低圧蒸気は、再び加圧流動床ボイラ２で熱回収が行なわれ、高温蒸気となり再熱蒸気タービン９に送られ再熱蒸気タービン９を回転駆動する。これら蒸気タービン８，９は、蒸気タービン発電機１０を駆動し、電気出力を得る。
【００２２】
再熱蒸気タービン９で仕事をした蒸気は、低温低圧蒸気となって復水器１１で海水と熱交換され、凝縮して復水となり復水器１１内に貯められる。復水器１１内に貯められた復水は、復水器１１出口に設置された復水ポンプ１２にて昇圧されて低圧給水加熱器１４および排ガス熱交換器６へ給水され、蒸気タービン抽気４３およびガスタービンからの排ガスと熱交換を行う。
【００２３】
その後この給水は、脱気器１７に導かれて脱気される。脱気された給水はさらに給水ポンプ２０にて昇圧されて高圧給水加熱器２２へ給水され、その後、加圧流動床ボイラ２へ高温給水として給水される。
【００２４】
なおこの系統で、緊急停止時においては、加圧流動床ボイラ２内の加熱管を高温高圧ガスから保護するために、少量の給水を供給しクーリング蒸気を加熱管へ供給する必要があり、復水ポンプ１２出口の脱気器水位調節弁１３にて脱気器１７水位を調節し、かつ給水ポンプ２０の回転数、または給水流量調節弁２１にて給水流量を制御するようにしている。
【００２５】
また、起動停止時においても、加圧流動床ボイラ２へ少量の給水を復水ポンプ１２出口の脱気器水位調節弁１３にて脱気器１７水位を調節し、かつ給水ポンプ２０の回転数、または給水流量調節弁２１にて給水流量を制御するようにしている。
【００２６】
本発明はこのような加圧流動複合発電プラントにおいて、排ガス熱交換器６内の給水を置換するため脱気器１７の給水を脱気器１７から排ガス熱交換器６入口管へ供給するための置換水供給系統，すなわちポンプ２４および配管弁２６を設けたことである。
【００２７】
これにより、緊急停止時は給水量を急速に減少させると脱気器水位調節弁１３の応答遅れ、脱気器１７内の蒸気凝縮および脱気器１７内給水の落水により脱気器１７水位が上昇し脱気器水位調節弁１３が脱気器水位計１８からの信号により全閉となり脱気器１７への給水が停止された場合でも脱気器１７の給水を脱気器１７出口から給水循環ポンプ２４へ供給し、昇圧した後給水循環ポンプ出口流量計２５、給水循環ポンプ出口流量調節弁２６、排ガス熱交換器６入口管、排ガス熱交換器６、脱気器１７へ循環することが可能となり、ガス側および灰側からの入熱による排ガス熱交換器６廻りの温度上昇を緩和することが可能となるのである。
【００２８】
特に給水循環ポンプ出口流量計２５からの信号により給水循環ポンプ出口流量調節弁２６を制御することができるため安定した運転状態を確保することが可能となるのである。
【００２９】
また、起動停止時は少量の給水を加圧流動床ボイラ２へ給水する必要があり、脱気器水位計１８からの信号により脱気器水位調節弁１３が ＯＮ−ＯＦＦ 動作になると考えられるが、前記の運転を行うことにより、ガス側および灰側からの入熱による排ガス熱交換器６廻りの温度上昇を緩和することが可能となる。
【００３０】
図２は、本発明のもう一つの実施例を示すもので、脱気器１７の給水を排ガス・灰クーラ３０から排ガス熱交換器６の入口管へ供給するための置換水供給系統を設けたものである。すなわち、脱気器内１７の給水は、高温冷却水タンク水位調節弁２７を介して高温冷却水タンク２８へ供給され、高温冷却水タンク２８へ供給された給水（高温冷却水）は、高温冷却水ポンプ２９で昇圧し、排ガス・灰クーラ３０にて熱交換後冷却水圧力調節弁３１を介し高温冷却水タンク２８へ戻され、排ガス・灰クーラ３０の交換熱量は、高温冷却水タンク２８内でフラッシュし、高温冷却水タンク圧力調節弁３２を介し低圧給水加熱器１４へ回収される。
【００３１】
この場合、排ガス熱交換器６内の給水を置換するため脱気器１７の給水を排ガス・灰クーラ３０出口（または入口）から排ガス熱交換器６入口管へ供給するための配管弁が設けられていることから、これにより、緊急停止時に給水量を急速に減少させると脱気器水位調節弁１３の応答遅れ、脱気器１７内の蒸気凝縮および脱気器１７内給水の落水により脱気器１７水位が上昇し脱気器水位調節弁１３が脱気器水位計１８から信号により全閉となり脱気器１７への給水が停止された場合でも排ガス・灰クーラ出口給水流量調節弁３４を作動させると高温冷却水タンク２８の水位が低下するため脱気器１７内の給水が高温冷却水タンク水位計３５らの信号により高温冷却水タンク水位調節弁２７が作動し脱気器１７内の給水が高温冷却水タンク２８へ供給される。
【００３２】
そして、高温冷却水タンク２８へ供給された給水（高温冷却水）は、高温冷却水ポンプ２９で昇圧され排ガス・灰クーラ３０出口から排ガス・灰クーラ出口給水流量計３３、排ガス・灰クーラ出口給水流量調節弁３４、排ガス熱交換器６入口管、排ガス熱交換器６、脱気器１７へ循環することが可能となり、ガス側および灰側からの入熱による排ガス熱交換器１７廻りの温度上昇を緩和することが可能となる。特に排ガス・灰クーラ出口給水流量計３３からの信号により排ガス・灰クーラ出口給水流量調節弁３４を制御することができるため安定した運転状態を確保することが可能となる。
【００３３】
また、起動停止時は少量の給水を加圧流動床ボイラ２へ給水する必要があり、脱気器水位計１８からの信号により脱気器水位調節弁１３が ＯＮ−ＯＦＦ 動作になると考えられるが、前記の運転を行うことにより、ガス側および灰側からの入熱による排ガス熱交換器６廻りの温度上昇を緩和することが可能となる。
【００３４】
図３は、さらに本発明の他の実施例を示すもので、この場合には、排ガス熱交換器６出口の給水を復水器１１へ供給するための配管および弁を設け、さらに脱気器水位計１８、脱気器圧力計１９および排ガス熱交換器出口給水温度計１６および緊急停止モードから構成される給水タンプ流量制御装置４１からの信号により給水タンプ流量調節弁３９を制御したことである。
【００３５】
これにより、緊急停止時（燃料系停止、蒸気タービン停止、ガスタービン停止等）は、給水タンプ流量制御装置４１からの信号により給水タンプ流量調節弁３９を制御することにより排ガス熱交換器６出口の給水を復水器１１へ供給すると復水器１１から排ガス熱交換器６出口の循環量が増加し、脱気器水位調節弁１３の通水量が増えるため脱気器水位調節弁１３の連続制御が可能性となる。このため、排ガス熱交換器６の給水量が増加し、ガス側および灰側からの入熱による排ガス熱交換器６廻りの温度上昇を緩和することがき安定した運転状態を確保することが可能となる。
【００３６】
また、起動停止時に少量の給水を加圧流動床ボイラ２へ供給する場合でも給水タンプ流量調節弁３９を制御することにより排ガス熱交換器６出口の給水を復水器１１へ供給すると復水器１１から排ガス熱交換器６出口の循環量が増加し排ガス熱交換器６出口の給水を復水器１１へ供給することにより、脱気器水位調節弁１３の通水量が増加するため脱気器水位調節弁１３の連続制御が可能性となる。このため、排ガス熱交換器６の給水量が増加し、ガス側および灰側からの入熱による排ガス熱交換器６廻りの温度上昇を緩和することがき安定した運転状態を確保することが可能となる。
【００３７】
図４は、この実施例の概略制御説明図で、脱気器圧力計１９、排ガス熱交換器出口給水温度計１６および緊急停止モードの弁固定値への切替え回路並びに給水タンプ流量調節弁３９から構成され、脱気器１７内圧（関数により脱気器内圧を飽和温度に変換）と排ガス熱交換器出口給水温度の偏差を一定とし比例・積分をおこない切替えスイッチを介し給水タンプ流量調節弁３９を制御する。また緊急停止モードの場合は、給水タンプ流量が一定量（アナログ設定値）になるよう切替スイッチを介し給水タンプ流量調節弁３９を制御する。このため、起動停止は、排ガス熱交換器出口給水温度を脱気器１７内圧を飽和温度に以下になるよう制御される。また、緊急停止時は一定量（アナログ設定値）の給水を、排ガス熱交換器出口から給水タンプ流量調節弁３９を介し復水器１１に回収することが可能となる。
【００３８】
図５は、本発明の他の実施例を示す構成図で、前記実施例（図２）と（図３）を組み合わせ、さらに復水流量計１５、脱気器水位計１８、給水ダンプ流量計３８、給水流量計２３および緊急停止モードの信号により構成される脱気器水位制御装置４０を設けたことである。
【００３９】
これにより、緊急停止時（燃料系停止、蒸気タービン停止、ガスタービン停止等）は、脱気器水位制御装置４０からの信号により脱気器水位調節弁１３を制御することによりクーリング蒸気を発生するに必要な給水を加圧流動床ボイラ２へ供給することができる。
【００４０】
さらに、排ガス熱交換器出口温度が上昇すると、排ガス熱交換器６出口の給水を復水器１１へ供給し復水器１１から排ガス熱交換器６出口の循環量が増加し、脱気器水位調節弁１３の通水量が増えるため脱気器水位調節弁１３の連続制御が可能性となる。このため、排ガス熱交換器６の給水量が増加し、ガス側および灰側からの入熱による排ガス熱交換器６廻りの温度上昇を緩和することができ安定した運転状態を確保することが可能となる。
【００４１】
また、起動停止時に少量の給水を加圧流動床ボイラ２へ供給する場合でも給水タンプ流量調節弁３９を制御することにより排ガス熱交換器６出口の給水を復水器１１へ供給すると復水器１１から排ガス熱交換器６出口の循環量が増加し排ガス熱交換器６出口の給水を復水器１１へ供給することにより、脱気器水位調節弁１３の通水量が増加するため脱気器水位調節弁１３の連続制御が可能性となる。このため、排ガス熱交換器６の給水量が増加し、ガス側および灰側からの入熱による排ガス熱交換器廻りの温度上昇を緩和することができ安定した運転状態を確保することが可能となる。
【００４２】
図６は、前述実施例（図５）の概略制御説明図である。本実施例は、復水流量計１５、脱気器水位計１８、給水ダンプ流量計３８、給水流量計２３および給水ダンプ流量に任意流量設定値を加えかつ最低流量を確保する様制限された流量設定回路および緊急停止モードの信号にてこの設定回路側へ切替え脱気器水位調節弁への制御設定値信号とする切替え回路並びに脱気器水位調節弁１３にて構成され、脱気器１７の出口給水量（給水流量）と脱気器１７の入口給水量（給水ダンプ流量、復水流量）により脱気器１７水位を補正し復水流量を脱気器水位調節弁１３で制御する。また脱気器１７水位が高くかつ緊急停止モードの場合においても常に給水ダンプ流量以上の復水流量を確保することが可能となる。
【００４３】
図７は、他の実施例（図６）の排ガス熱交換器廻りの流量特性図（緊急停止時モード時）である。給水タンプ流量が増加すると脱気器入口給水量が一定となり排ガス熱交換器６および脱気器水位調節弁１３の通水量が増加する。また、給水タンプ流量が無くなった場合は、脱気器水位調節弁１３を介し脱気器１７に少量の給水が供給される。なお、脱気器１７に供給された給水は、給水ポンプ２０にて昇圧し加圧流動床ボイラ２に給水される。
【００４４】
以上説明してきたようにこのように形成された加圧流動床複合発電プラントであると、給水を排ガス熱交換器へ供給するための供給系統が設けられていることから、緊急停止時および起動停止時に脱気器水位調節弁が全閉した場合であっても、排ガス熱交換器部へ給水が行われ、ガス側および灰側からの入熱による排ガス熱交換器廻りの温度上昇を緩和することができ安定した運転状態を確保することができるのである。
【００４５】
【発明の効果】
以上説明してきたように本発明によれば、プラントの起動停止時および緊急停止時に排ガス熱交換器廻りで発生するフラッシュを充分防止し、安定運転の確保，機器保護および信頼性の向上を図ることが可能なこの種の加圧流動床複合発電プラントを得ることができる。
【図面の簡単な説明】
【図１】本発明の加圧流動床複合発電プラントの一実施例を示す系統図である。
【図２】本発明の加圧流動床複合発電プラントの他の実施例を示す系統図である。
【図３】本発明の加圧流動床複合発電プラントの他の実施例を示す要部系統図である。
【図４】本発明の加圧流動床複合発電プラントの概略制御説明図である。
【図５】本発明の加圧流動床複合発電プラントの他の実施例を示す要部系統図である。
【図６】本発明の加圧流動床複合発電プラントの概略制御説明図である。
【図７】本発明の加圧流動床複合発電プラントの一実施例における流量特性図（緊急停止モード）である。
【図８】従来の加圧流動床複合発電プラントの要部系統図である。
【符号の説明】
１…ガスタービン圧縮機、２…加圧流動床ボイラ、３…燃料供給系統、４…ガスタービン、５…ガスタービン発電機、６…排ガス熱交換器、７…煙突、８…高圧蒸気タービン、９…再熱蒸気タービン、１０…蒸気タービン発電機、１１…復水器、１２…復水ポンプ、１３…脱気器水位調節弁、１４…低圧給水加熱器、１５…復水流量計、１６…排ガス熱交換器出口温度計、１７…脱気器、１８…脱気器水位計、１９…脱気器圧力計、２０…給水ポンプ、２１…給水流量調節弁、２２…高圧給水加熱器、２３…給水流量計、２４…給水循環ポンプ、２５…給水循環ポンプ出口流量計、２６…給水循環ポンプ出口流量調節弁、２７…高温冷却水タンク水位調節弁、２８…高温冷却水タンク、２９…高温冷却水ポンプ、３０…排ガス・灰クーラ、３１…冷却水圧力調節弁、３２…高温冷却水タンク圧力調節弁、３３…排ガス・灰クーラ出口給水流量計、３４…排ガス・灰クーラ出口給水流量調節弁、３５…高温冷却水タンク水位計、３６…高温冷却水タンク圧力計、３７…高温冷却水圧力計、３８…給水タンプ流量計、３９…給水タンプ流量調節弁、４０…脱気器水位制御装置、４１…給水タンプ流量制御装置、４２…抽気管、４３…抽気止め弁。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a pressurized fluidized bed boiler and a gas turbine and a steam turbine and in which pressurized fluidized bed combined cycle plant equipped with a, and the power plant.
[0002]
[Prior art]
This type of pressurized fluidized bed combined cycle power plant, which is conventionally generally used, has a low pressure feed water heater 14, 14 between a condensate pump 12 and a deaerator 17, as schematically shown in FIG. The exhaust gas / ash cooler 30 and the waste gas heat exchanger 6 are installed in parallel, and the amount of water supplied to the low pressure feed water heater 14, the exhaust gas / ash cooler 30 and the waste gas heat exchanger 6 is provided at the inlet or outlet thereof. In general, the supply of water to the deaerator 17 is controlled by a deaerator water level control valve 13 installed at the outlet of the condensate pump 12.
[0003]
Japanese Patent Application Laid-Open No. 6-185704 is an example of a related-art pressurized fluidized bed combined cycle power plant.
[0004]
[Problems to be solved by the invention]
In the pressurized fluidized bed combined cycle power plant formed as described above, at the time of emergency stop of the plant, if the amount of water supply is rapidly reduced, the response delay of the deaerator water level control valve 13 causes a delay in the deaerator 17. The deaerator water level rises due to the vapor condensation and the fall of the supply water in the deaerator, the deaerator water level control valve 13 is fully closed by a signal from the deaerator water level gauge 18, and the supply of water to the deaerator 17 is stopped.
[0005]
On the other hand, the feed water of the exhaust gas / ash cooler 30 and the exhaust gas heat exchanger 6 is heated by the heat input from the gas side and the ash side, so that the feed water around the exhaust gas / ash cooler 30 and the exhaust gas heat exchanger 6 is flushed ( It is easily presumed that water and steam) and damage to devices such as the exhaust gas / ash cooler 30 and the waste heat exchanger 6 and piping valves.
[0006]
Also, if a small amount of water is supplied to the boiler at the time of starting and stopping the plant, continuous control of the deaerator water level control valve 13 becomes impossible, and there is a possibility that the water supply to the deaerator 17 may be stopped (ON-OFF control). It is conceivable that the same event as time occurs. In the above-mentioned Japanese Patent Application Laid-Open No. 6-185704, the exhaust gas / ash cooler 30 and the waste gas heat exchanger due to heat input from the gas side and the ash side lack consideration in emergency stop and start-up stop. It was not possible to prevent around 6 water flushes.
[0007]
The present invention has been made in view of the above, and an object of the present invention is to sufficiently prevent a flash generated around an exhaust gas heat exchanger at the time of start-up and emergency stop of a plant to ensure stable operation, protect equipment, and improve reliability. to provide sexual improvement can be achieved for the main of a PFBC combined cycle plant, and a power plant.
[0008]
[Means for Solving the Problems]
That is, the present invention provides a pressurized fluidized bed boiler for generating steam, a steam turbine driven by steam generated by the pressurized fluidized bed boiler, and a gas turbine driven by combustion exhaust gas from the pressurized fluidized bed boiler. When, and a water system for supplying water to the PFBC boiler from the condenser of the steam turbine, the water supply system, and the exhaust gas heat exchanger for heating the feed water subjected to gas turbine exhaust gas heat exchanger, the exhaust gas In a pressurized fluidized bed combined cycle power plant provided with a deaerator for deaeration of feedwater supplied from a heat exchanger, the feedwater system is provided with the deaerator or deaerator outlet-side feedwater by the exhaust gas. A replacement water supply system for supplying replacement water to the exhaust gas heat exchanger as replacement water for the feedwater in the heat exchanger is provided to achieve the intended purpose.
[0009]
The present invention also provides a pressurized fluidized bed boiler for generating steam, a steam turbine driven by steam generated by the pressurized fluidized bed boiler, and a gas turbine driven by combustion exhaust gas from the pressurized fluidized bed boiler. When, and a water system for supplying water to the PFBC boiler from the condenser of the steam turbine, the water supply system, and the exhaust gas heat exchanger for heating the feed water subjected to gas turbine exhaust gas heat exchanger, the exhaust gas In a pressurized fluidized bed combined cycle power plant provided with a deaerator for deaeration of feedwater supplied from a heat exchanger, the feedwater is supplied to an outlet side of the exhaust gas heat exchanger to the condenser. A supply water circulation system is provided.
[0010]
In this case, the water supply circulation system is provided with a control valve, a flow meter, and a thermometer for controlling the replacement water from the exhaust gas heat exchanger outlet to the condenser to a specified amount at the time of emergency stop and start-up stop. It is.
[0011]
The present invention also provides a pressurized fluidized bed boiler for generating steam, a steam turbine driven by steam generated by the pressurized fluidized bed boiler, and a gas turbine driven by exhaust gas from the pressurized fluidized bed boiler. A water supply system for supplying water from the condenser of the steam turbine to the pressurized fluidized bed boiler, wherein the water supply system is provided with an exhaust gas heat exchanger, a feedwater heater, and a deaerator for heating the feedwater. In the combined pressure and fluidized bed power plant, supply water to the exhaust gas heat exchanger via the deaerator level control valve according to a signal from the water level control device of the deaerator at the time of emergency stop or start-up stop in the water supply system. And a control valve for controlling the supply replacement water amount to a specified amount is provided in the replacement water supply system.
[0012]
The present invention also provides a pressurized fluidized bed boiler for generating steam, a steam turbine driven by steam generated by the pressurized fluidized bed boiler, and a gas turbine driven by combustion exhaust gas from the pressurized fluidized bed boiler. And a water supply system for supplying water from the condenser of the steam turbine to the pressurized fluidized bed boiler, wherein the water supply system is provided with an exhaust gas heat exchanger, a feedwater heater, and a deaerator for heating feedwater. In the pressurized fluidized bed combined cycle power plant, the water supply system is provided with a replacement water supply system for supplying replacement water from the exhaust gas / ash cooler outlet to the exhaust gas heat exchanger at the time of emergency stop and start-up stop. A control valve and a flow meter are provided in the replacement water supply system to control the supply replacement water amount to a specified amount.
The present invention also provides a boiler for generating steam, a steam turbine driven by the steam generated by the boiler, a gas turbine driven by combustion gas, and a condensate for condensing the steam worked by the steam turbine. And a water supply system for supplying water from the condenser to the boiler. The water supply system heats the water by exchanging heat between the water supplied from the condenser and the exhaust gas of the gas turbine. In a power plant having an exhaust gas heat exchanger and a deaerator that deaerates feedwater supplied from the exhaust gas heat exchanger, the feedwater system is provided with the deaerator or the deaerator outlet side feedwater. A water supply system for supplying to the exhaust gas heat exchanger is provided.
[0013]
That is, in the pressurized fluidized bed combined cycle power plant formed in this manner, the supply of water from the deaerator to the exhaust gas heat exchanger from the deaerator outlet to replace the water supply in the exhaust gas heat exchanger. Since the system is provided, even if the deaerator water level control valve is fully closed at the time of emergency stop and start-up stop, water supply to the deaerator is supplied from the deaerator to the exhaust gas heat exchanger inlet pipe. Therefore, the temperature rise around the exhaust gas heat exchanger due to heat input from the gas side and the ash side can be reduced, and a stable operation state can be secured.
[0014]
Also, in order to replace the water supply to the exhaust gas heat exchanger, a system is provided to supply the water at the exhaust gas / ash cooler outlet from the exhaust gas / ash cooler outlet pipe to the exhaust gas heat exchanger. Even when the deaerator water level control valve is fully closed at the time of starting and stopping, the water supply at the exhaust gas / ash cooler outlet can be supplied to the exhaust gas heat exchanger from the exhaust gas / ash cooler outlet pipe. As a result, the temperature rise around the exhaust gas heat exchanger due to the heat input can be reduced, and a stable operation state can be secured.
[0015]
In addition, since a system is provided to supply the feedwater at the outlet of the exhaust gas heat exchanger to the condenser, even when a small amount of feedwater is supplied to the pressurized fluidized bed boiler at the time of emergency stop and start-up stop, By supplying the water supply at the outlet of the exchanger to the condenser, the flow rate of the deaerator water level control valve is increased, so that the deaerator water level control valve can be continuously controlled. For this reason, the water supply amount of the exhaust gas heat exchanger increases, and the temperature rise around the exhaust gas heat exchanger due to heat input from the gas side and the ash side can be reduced, and a stable operation state can be secured. .
[0016]
Another invention is an exhaust gas heat exchanger in which the control of the deaerator water level control valve is controlled in advance by a signal from a deaerator water level device (water supply flow rate, water supply dump flow rate, deaerator water level and emergency stop mode). Water is supplied from the condensate pump outlet, and even if a small amount of water is supplied to the boiler at the time of emergency stop and start-up stop, the water at the condensate pump outlet is discharged through the deaerator level control valve. Since water can be supplied to the heat exchanger, a temperature increase around the exhaust gas heat exchanger due to heat input from the gas side and the ash side can be reduced, and a stable operation state can be secured.
[0017]
Further, the present invention provides a water supply circulation pump outlet flow meter for adjusting the water supply amount and a water supply circulation pump outlet flow rate control valve in the piping section of the water supply circulation pump outlet, so that emergency stop and start-up stop are performed. The amount of water supplied from the deaerator to the exhaust gas heat exchanger at the time can be adjusted to the specified value, and the temperature rise around the exhaust gas heat exchanger due to heat input from the gas side and the ash side can be moderated and stable It is possible to secure the operation state.
[0018]
In addition, a feed water dump flow meter, a feed water dump flow control valve, a deaerator pressure gauge, a condensate dump flow meter, and an exhaust gas heat exchanger thermometer for adjusting the amount of water supplied from the exhaust gas heat exchanger outlet to the condenser Therefore, even when a small amount of water is supplied to the boiler at the time of emergency stop and start-up stop, the water at the outlet of the exhaust gas heat exchanger is supplied to the condenser, so that the deaerator water level control valve can be connected. Since the amount of water increases, continuous control of the deaerator water level control valve becomes possible. For this reason, the amount of water supplied to the exhaust gas heat exchanger increases, and the temperature rise around the exhaust gas heat exchanger due to heat input from the gas side and the ash side can be reduced, and a stable operation state can be secured. is there.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. FIG. 1 shows a system of the combined pressurized fluidized bed power generation plant. In the figure, 4 is a gas turbine, 1 is a gas turbine compressor, 2 is a pressurized fluidized bed boiler, 8 is a high pressure steam turbine, and 9 is a reheat steam turbine. 5 is a gas turbine generator, 10 is a steam turbine generator, and 7 is a chimney for exhaust gas.
[0020]
First, as shown in this figure, the air introduced into the gas turbine compressor 1 is introduced into the pressurized fluidized bed boiler 2 as high-pressure air. The introduced high-pressure air burns together with the fuel supplied from the fuel supply system 3 in the pressurized fluidized-bed boiler, becomes high-temperature and high-pressure fuel gas, and expands and performs work in the gas turbine 4. The gas turbine 4 rotates a gas turbine generator 5 to obtain an electric output. After that, the gas turbine exhaust gas that has completed this work exchanges heat with feed water in the exhaust gas heat exchanger 6 and is eventually released from the chimney 7 to the atmosphere.
[0021]
On the other hand, the high-temperature feed water supplied to the pressurized fluidized-bed boiler 2 is heated by the pressurized fluidized-bed boiler 2 to become high-temperature high-pressure steam, sent to the high-pressure steam turbine 8, and drives the high-pressure steam turbine 8 to rotate. Further, the expanded low-pressure steam is subjected to heat recovery in the pressurized fluidized-bed boiler 2 again, becomes high-temperature steam, and is sent to the reheat steam turbine 9 to rotate the reheat steam turbine 9. These steam turbines 8 and 9 drive a steam turbine generator 10 to obtain an electric output.
[0022]
The steam that has worked in the reheat steam turbine 9 becomes low-temperature and low-pressure steam, is heat-exchanged with seawater in the condenser 11, condenses and becomes condensed water, and is stored in the condenser 11. The condensate stored in the condenser 11 is boosted in pressure by a condensate pump 12 installed at the outlet of the condenser 11 and supplied to the low-pressure feed water heater 14 and the exhaust gas heat exchanger 6, and the steam turbine bleed 43 And heat exchange with the exhaust gas from the gas turbine.
[0023]
Thereafter, this water supply is guided to the deaerator 17 and deaerated. The degassed feed water is further pressurized by a feed pump 20 and supplied to a high pressure feed water heater 22, and then supplied to the pressurized fluidized bed boiler 2 as high temperature feed water.
[0024]
In this system, in the event of an emergency stop, it is necessary to supply a small amount of water and supply cooling steam to the heating pipe in order to protect the heating pipe in the pressurized fluidized-bed boiler 2 from high-temperature and high-pressure gas. The water level of the deaerator 17 is adjusted by the deaerator water level control valve 13 at the outlet of the water pump 12, and the number of revolutions of the water supply pump 20 or the water supply flow rate is controlled by the water supply flow rate control valve 21.
[0025]
Further, even when the start-up is stopped, a small amount of water is supplied to the pressurized fluidized-bed boiler 2 by controlling the water level of the deaerator 17 with the deaerator water level control valve 13 at the outlet of the condensing pump 12, and the rotation speed of the water supply pump 20. Alternatively, the water supply flow rate is controlled by the water supply flow rate control valve 21.
[0026]
In the pressurized fluidized-flow combined cycle power plant, the present invention is to supply water from the deaerator 17 from the deaerator 17 to the inlet pipe of the exhaust gas heat exchanger 6 to replace the water supply in the exhaust gas heat exchanger 6. That is, a replacement water supply system, that is, a pump 24 and a piping valve 26 are provided.
[0027]
As a result, when the water supply amount is rapidly reduced during an emergency stop, the response of the deaerator water level control valve 13 is delayed, and the vapor level in the deaerator 17 and the water supply in the deaerator 17 cause the water level of the deaerator 17 to drop. Even when the deaerator water level control valve 13 rises and is completely closed by a signal from the deaerator water level gauge 18 and the supply of water to the deaerator 17 is stopped, the water supply of the deaerator 17 is supplied from the outlet of the deaerator 17. After being supplied to the circulation pump 24 and pressurized, it can be circulated to the water supply circulation pump outlet flow meter 25, the water supply circulation pump outlet flow control valve 26, the exhaust gas heat exchanger 6 inlet pipe, the exhaust gas heat exchanger 6, and the deaerator 17. This makes it possible to alleviate a temperature rise around the exhaust gas heat exchanger 6 due to heat input from the gas side and the ash side.
[0028]
In particular, since the feed water circulation pump outlet flow rate control valve 26 can be controlled by a signal from the feed water circulation pump outlet flow meter 25, a stable operation state can be ensured.
[0029]
Also, when starting and stopping, it is necessary to supply a small amount of water to the pressurized fluidized-bed boiler 2, and it is considered that a signal from the deaerator water level gauge 18 causes the deaerator water level control valve 13 to be turned ON / OFF. By performing the above-described operation, it is possible to reduce a temperature rise around the exhaust gas heat exchanger 6 due to heat input from the gas side and the ash side.
[0030]
FIG. 2 shows another embodiment of the present invention, in which a replacement water supply system for supplying water of the deaerator 17 from the exhaust gas / ash cooler 30 to the inlet pipe of the exhaust gas heat exchanger 6 is provided. Things. That is, the supply water in the deaerator 17 is supplied to the high-temperature cooling water tank 28 via the high-temperature cooling water tank water level control valve 27, and the supply water (high-temperature cooling water) supplied to the high-temperature cooling water tank 28 is The pressure is raised by the water pump 29, heat exchange is performed by the exhaust gas / ash cooler 30, and the heat is returned to the high temperature cooling water tank 28 via the cooling water pressure control valve 31. And is recovered to the low-pressure feed water heater 14 via the high-temperature cooling water tank pressure control valve 32.
[0031]
In this case, a pipe valve for supplying the water of the deaerator 17 from the outlet (or inlet) of the exhaust gas / ash cooler 30 to the inlet pipe of the exhaust gas heat exchanger 6 to replace the water supply in the exhaust gas heat exchanger 6 is provided. Therefore, if the amount of water supply is rapidly reduced during an emergency stop, the response time of the deaerator water level control valve 13 is delayed, the steam is condensed in the deaerator 17, and the supply water in the deaerator 17 is dropped. Even if the water level of the deaerator 17 rises and the deaerator water level control valve 13 is fully closed by a signal from the deaerator water level gauge 18 and the supply of water to the deaerator 17 is stopped, the exhaust water / ash cooler outlet water supply flow rate control valve 34 is operated. When activated, the water level in the high-temperature cooling water tank 28 drops, so that the water in the deaerator 17 is supplied with a signal from the high-temperature cooling water tank water level gauge 35 and the high-temperature cooling water tank water level control valve 27 is operated, and the inside of the deaerator 17 is operated. High-temperature cooling water tank 2 It is supplied to.
[0032]
The supply water (high-temperature cooling water) supplied to the high-temperature cooling water tank 28 is pressurized by the high-temperature cooling water pump 29 and is supplied from the exhaust gas / ash cooler 30 outlet to the exhaust gas / ash cooler outlet feed water flow meter 33, the exhaust gas / ash cooler outlet water supply. It is possible to circulate to the flow rate control valve 34, the exhaust gas heat exchanger 6 inlet pipe, the exhaust gas heat exchanger 6, and the deaerator 17, and the temperature rise around the exhaust gas heat exchanger 17 due to heat input from the gas side and the ash side. Can be alleviated. Particularly, since the exhaust gas / ash cooler outlet feedwater flow rate control valve 34 can be controlled by a signal from the exhaust gas / ash cooler outlet feedwater flow meter 33, a stable operation state can be ensured.
[0033]
Also, when starting and stopping, it is necessary to supply a small amount of water to the pressurized fluidized-bed boiler 2, and it is considered that a signal from the deaerator water level gauge 18 causes the deaerator water level control valve 13 to be turned ON / OFF. By performing the above-described operation, it is possible to reduce a temperature rise around the exhaust gas heat exchanger 6 due to heat input from the gas side and the ash side.
[0034]
FIG. 3 shows still another embodiment of the present invention. In this case, a pipe and a valve for supplying the feed water at the outlet of the exhaust gas heat exchanger 6 to the condenser 11 are provided. That is, the feedwater tamper flow control valve 39 is controlled by a signal from the water level gauge 18, the deaerator pressure gauge 19, the exhaust water heat exchanger outlet feedwater thermometer 16, and the feedwater tamper flow control device 41 constituted of an emergency stop mode. .
[0035]
Thus, during an emergency stop (fuel system stop, steam turbine stop, gas turbine stop, etc.), the feed water tamper flow control valve 39 is controlled by a signal from the feed water tamper flow control device 41 so that the outlet of the exhaust gas heat exchanger 6 is controlled. When the feed water is supplied to the condenser 11, the circulation amount from the condenser 11 to the exhaust gas heat exchanger 6 outlet increases, and the flow rate of the deaerator water level control valve 13 increases, so that the deaerator water level control valve 13 is continuously controlled. Becomes a possibility. For this reason, the amount of water supplied to the exhaust gas heat exchanger 6 increases, and the temperature rise around the exhaust gas heat exchanger 6 due to heat input from the gas side and the ash side can be mitigated, and a stable operation state can be secured. Become.
[0036]
Further, even when a small amount of water is supplied to the pressurized fluidized-bed boiler 2 at the time of starting and stopping, the supply water at the outlet of the exhaust gas heat exchanger 6 is supplied to the condenser 11 by controlling the water supply tamping flow control valve 39. Since the amount of circulation at the outlet of the exhaust gas heat exchanger 6 increases from 11 and water supplied at the outlet of the exhaust gas heat exchanger 6 is supplied to the condenser 11, the amount of water flowing through the deaerator water level control valve 13 increases, so that the deaerator Continuous control of the water level control valve 13 becomes possible. For this reason, the amount of water supplied to the exhaust gas heat exchanger 6 increases, and the temperature rise around the exhaust gas heat exchanger 6 due to heat input from the gas side and the ash side can be mitigated, and a stable operation state can be secured. Become.
[0037]
FIG. 4 is a schematic control explanatory diagram of this embodiment. FIG. 4 shows a deaerator pressure gauge 19, an exhaust gas heat exchanger outlet feedwater thermometer 16, a switching circuit for switching to a valve fixed value in an emergency stop mode, and a feedwater tamper flow control valve 39. The deviation of the deaerator 17 internal pressure (conversion of the deaerator internal pressure to the saturation temperature by a function) and the deviation of the feed water temperature at the outlet of the exhaust gas heat exchanger are made constant and proportional / integral is performed. Control. In the case of the emergency stop mode, the water supply tamping flow control valve 39 is controlled via the changeover switch so that the water tamping flow becomes a constant amount (an analog set value). For this reason, the start / stop is controlled so that the exhaust water heat exchanger outlet feedwater temperature becomes equal to or lower than the internal pressure of the deaerator 17 at the saturation temperature. Further, at the time of an emergency stop, it is possible to recover a fixed amount (water supply amount) of water from the exhaust gas heat exchanger outlet to the condenser 11 through the water supply tamping flow control valve 39.
[0038]
FIG. 5 is a block diagram showing another embodiment of the present invention, which combines the above embodiments (FIG. 2) and (FIG. 3), and further includes a condensate flow meter 15, a deaerator water level meter 18, and a feedwater dump flow meter. 38, a water supply flowmeter 23 and a deaerator water level control device 40 constituted by an emergency stop mode signal.
[0039]
Thus, during an emergency stop (fuel system stop, steam turbine stop, gas turbine stop, etc.), cooling steam is generated by controlling the deaerator water level control valve 13 with a signal from the deaerator water level control device 40. Can be supplied to the pressurized fluidized-bed boiler 2.
[0040]
Further, when the temperature of the exhaust gas heat exchanger outlet rises, the water supply at the outlet of the exhaust gas heat exchanger 6 is supplied to the condenser 11, and the circulation amount from the condenser 11 to the outlet of the exhaust gas heat exchanger 6 increases, and the deaerator water level is increased. Since the amount of water flowing through the control valve 13 increases, continuous control of the deaerator water level control valve 13 becomes possible. For this reason, the amount of water supplied to the exhaust gas heat exchanger 6 increases, and the temperature rise around the exhaust gas heat exchanger 6 due to heat input from the gas side and the ash side can be reduced, and a stable operation state can be secured. It becomes.
[0041]
Further, even when a small amount of water is supplied to the pressurized fluidized-bed boiler 2 at the time of starting and stopping, the supply water at the outlet of the exhaust gas heat exchanger 6 is supplied to the condenser 11 by controlling the water supply tamping flow control valve 39. Since the amount of circulation at the outlet of the exhaust gas heat exchanger 6 increases from 11 and water supplied at the outlet of the exhaust gas heat exchanger 6 is supplied to the condenser 11, the amount of water flowing through the deaerator water level control valve 13 increases, so that the deaerator Continuous control of the water level control valve 13 becomes possible. For this reason, the amount of water supplied to the exhaust gas heat exchanger 6 increases, and the temperature rise around the exhaust gas heat exchanger due to heat input from the gas side and the ash side can be reduced, and a stable operating state can be secured. Become.
[0042]
FIG. 6 is a schematic control explanatory diagram of the above-described embodiment (FIG. 5). In this embodiment, the condensate flow meter 15, the deaerator water level meter 18, the feed water dump flow meter 38, the feed water flow meter 23, and the flow rate limited to add an arbitrary flow rate set value to the feed water dump flow rate and secure the minimum flow rate. The deaerator 17 includes a switching circuit that switches to the setting circuit side by a setting circuit and a signal of the emergency stop mode to be a control set value signal to the deaerator water level control valve, and a deaerator water level control valve 13. The deaerator 17 water level is corrected by the outlet water supply amount (water supply flow rate) and the inlet water supply amount (water supply dump flow rate, condensate flow rate) of the deaerator 17, and the condensate flow rate is controlled by the deaerator water level control valve 13. Further, even in the case where the water level of the deaerator 17 is high and the emergency stop mode is set, it is possible to always secure a condensate flow rate equal to or higher than the feed water dump flow rate.
[0043]
FIG. 7 is a flow characteristic diagram (at the time of emergency stop mode) around the exhaust gas heat exchanger of another embodiment (FIG. 6). When the flow rate of the water supply tamper increases, the water supply amount at the deaerator inlet becomes constant, and the water flow amount of the exhaust gas heat exchanger 6 and the deaerator water level control valve 13 increases. Further, when the flow rate of the water supply tamper is exhausted, a small amount of water is supplied to the deaerator 17 via the deaerator water level control valve 13. The water supplied to the deaerator 17 is pressurized by the water supply pump 20 and supplied to the pressurized fluidized-bed boiler 2.
[0044]
As described above, in the pressurized fluidized bed combined cycle power plant formed as described above, the supply system for supplying the feedwater to the exhaust gas heat exchanger is provided. Even when the deaerator water level control valve is sometimes fully closed, water is supplied to the exhaust gas heat exchanger to mitigate the temperature rise around the exhaust gas heat exchanger due to heat input from the gas side and ash side. Therefore, a stable operation state can be ensured.
[0045]
【The invention's effect】
As described above, according to the present invention, it is possible to sufficiently prevent the flash generated around the exhaust gas heat exchanger at the time of start-up and emergency stop of the plant, to secure stable operation, protect equipment, and improve reliability. This type of pressurized fluidized bed combined cycle power plant capable of performing the above-mentioned steps can be obtained.
[Brief description of the drawings]
FIG. 1 is a system diagram showing one embodiment of a combined pressurized fluidized-bed power plant of the present invention.
FIG. 2 is a system diagram showing another embodiment of a combined pressurized fluidized-bed power plant of the present invention.
FIG. 3 is a main part system diagram showing another embodiment of the combined pressurized fluidized-bed power plant of the present invention.
FIG. 4 is a schematic control explanatory diagram of the combined pressurized fluidized-bed power plant of the present invention.
FIG. 5 is a main part system diagram showing another embodiment of the pressurized fluidized bed combined cycle power plant of the present invention.
FIG. 6 is a schematic control explanatory diagram of the combined pressurized fluidized-bed power plant of the present invention.
FIG. 7 is a flow rate characteristic diagram (emergency stop mode) in one embodiment of the combined pressurized fluidized-bed power plant of the present invention.
FIG. 8 is a main part system diagram of a conventional pressurized fluidized bed combined cycle power plant.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Gas turbine compressor, 2 ... Pressurized fluidized bed boiler, 3 ... Fuel supply system, 4 ... Gas turbine, 5 ... Gas turbine generator, 6 ... Exhaust gas heat exchanger, 7 ... Chimney, 8 ... High pressure steam turbine, 9: Reheat steam turbine, 10: Steam turbine generator, 11: Condenser, 12: Condenser pump, 13: Deaerator water level control valve, 14: Low pressure feed water heater, 15: Condenser flow meter, 16 ... Exhaust gas heat exchanger outlet thermometer, 17 ... Deaerator, 18 ... Deaerator water level gauge, 19 ... Deaerator pressure gauge, 20 ... Feed water pump, 21 ... Feed water flow control valve, 22 ... High pressure feed water heater 23: feed water flow meter, 24: feed water circulation pump, 25: feed water circulation pump outlet flow meter, 26: feed water circulation pump outlet flow control valve, 27: high temperature cooling water tank water level control valve, 28: high temperature cooling water tank, 29 ... High-temperature cooling water pump, 30 ... exhaust gas / ash cooler, 3 ... Cooling water pressure control valve, 32 ... High temperature cooling water tank pressure control valve, 33 ... Exhaust gas / ash cooler outlet feed water flow control valve, 34 ... Exhaust gas / ash cooler outlet feed water flow control valve, 35 ... High temperature cooling water tank water level gauge, 36 ... high-temperature cooling water tank pressure gauge, 37 ... high-temperature cooling water pressure gauge, 38 ... water supply tamping flow meter, 39 ... water supply tamping flow control valve, 40 ... deaerator water level control device, 41 ... water supply tamping flow control device, 42 ... Bleed pipe, 43 ... Bleed stop valve.

Claims (7)

蒸気を発生させる加圧流動床ボイラと、この加圧流動床ボイラで発生した蒸気により駆動される蒸気タービンと、前記加圧流動床ボイラからの燃焼排ガスにより駆動されるガスタービンと、前記蒸気タービンの復水器から前記加圧流動床ボイラへ給水する給水系統とを備え、前記給水系統に、ガスタービン排ガスと熱交換を行い給水を加熱する排ガス熱交換器と、該排ガス熱交換器から供給される給水を脱気する脱気器が設けられている加圧流動床複合発電プラントにおいて、
前記給水系統に、前記脱気器または脱気器出口側の給水を、前記排ガス熱交換器内の給水の置換水として該排ガス熱交換器に供給する置換水供給系統を設けたことを特徴とする加圧流動床複合発電プラント。A pressurized fluidized bed boiler for generating steam, a steam turbine driven by steam generated by the pressurized fluidized bed boiler, a gas turbine driven by combustion exhaust gas from the pressurized fluidized bed boiler, and the steam turbine A water supply system for supplying water from the condenser to the pressurized fluidized-bed boiler, wherein the water supply system exchanges heat with gas turbine exhaust gas to heat the feed water, and supplies the exhaust gas from the exhaust gas heat exchanger. In a pressurized fluidized bed combined cycle power plant provided with a deaerator for degassing the feedwater to be supplied ,
The water supply system is provided with a replacement water supply system that supplies the deaerator or deaerator outlet-side supply water to the exhaust gas heat exchanger as replacement water for the feed water in the exhaust gas heat exchanger. Pressurized fluidized bed combined cycle power plant. 置換水供給系統が、供給ポンプおよび供給流量を調整する調整弁を備えたものである請求項１記載の加圧流動床複合発電プラント。The pressurized fluidized bed combined cycle power plant according to claim 1, wherein the replacement water supply system includes a supply pump and a regulating valve for regulating a supply flow rate. 蒸気を発生させる加圧流動床ボイラと、この加圧流動床ボイラで発生した蒸気により駆動される蒸気タービンと、前記加圧流動床ボイラからの燃焼排ガスにより駆動されるガスタービンと、前記蒸気タービンの復水器から前記加圧流動床ボイラへ給水する給水系統とを備え、前記給水系統に、ガスタービン排ガスと熱交換を行い給水を加熱する排ガス熱交換器と、該排ガス熱交換器から供給される給水を脱気する脱気器が設けられている加圧流動床複合発電プラントにおいて、
前記給水系統に、前記排ガス熱交換器の出口側の給水を前記復水器へ供給する給水循環系統を設けたことを特徴とする加圧流動床複合発電プラント。A pressurized fluidized bed boiler for generating steam, a steam turbine driven by steam generated by the pressurized fluidized bed boiler, a gas turbine driven by combustion exhaust gas from the pressurized fluidized bed boiler, and the steam turbine A water supply system for supplying water from the condenser to the pressurized fluidized-bed boiler, wherein the water supply system exchanges heat with gas turbine exhaust gas to heat the feed water, and supplies the exhaust gas from the exhaust gas heat exchanger. In a pressurized fluidized bed combined cycle power plant provided with a deaerator for degassing the feedwater to be supplied ,
The combined pressurized fluidized-bed power plant further comprising a feedwater circulation system that supplies feedwater on the outlet side of the exhaust gas heat exchanger to the condenser in the feedwater system. 前記給水循環系統に、緊急停止時および起動停止時に排ガス熱交換器出口から復水器への置換水を規定量に制御する調節弁，流量計および温度計を設けてなる請求項３記載の加圧流動床複合発電プラント。4. The water supply circulation system according to claim 3, further comprising a control valve, a flow meter, and a thermometer for controlling the replacement water from the exhaust gas heat exchanger outlet to the condenser to a specified amount at the time of emergency stop and startup stop. Pressure fluidized bed combined cycle power plant. 蒸気を発生させる加圧流動床ボイラと、この加圧流動床ボイラで発生した蒸気により駆動される蒸気タービンと、前記加圧流動床ボイラからの燃焼排ガスにより駆動されるガスタービンと、前記蒸気タービンの復水器から前記加圧流動床ボイラへ給水する給水系統とを備え、前記給水系統に、給水を加熱する排ガス熱交換器，給水加熱器および脱気器が設けられている加圧流動床複合発電プラントにおいて、
前記給水系統に、緊急停止または起動停止時に前記脱気器の水位制御装置からの信号により脱気器レベル調節弁を介して前記排ガス熱交換器へ置換水を供給する置換水供給系統を設けるとともに、この置換水供給系統に、供給置換水量を規定量に制御する調節弁を設けたことを特徴とする加圧流動床複合発電プラント。A pressurized fluidized bed boiler for generating steam, a steam turbine driven by steam generated by the pressurized fluidized bed boiler, a gas turbine driven by combustion exhaust gas from the pressurized fluidized bed boiler, and the steam turbine And a water supply system for supplying water from the condenser to the pressurized fluidized-bed boiler, wherein the water supply system is provided with an exhaust gas heat exchanger for heating feedwater, a feedwater heater, and a deaerator. In a combined cycle power plant,
The water supply system is provided with a replacement water supply system that supplies replacement water to the exhaust gas heat exchanger via a deaerator level control valve by a signal from the water level control device of the deaerator at the time of emergency stop or startup stop. A pressurized fluidized bed combined cycle power plant, wherein the replacement water supply system is provided with a control valve for controlling the supply replacement water amount to a specified amount. 蒸気を発生させる加圧流動床ボイラと、この加圧流動床ボイラで発生した蒸気により駆動される蒸気タービンと、前記加圧流動床ボイラからの燃焼排ガスにより駆動されるガスタービンと、前記蒸気タービンの復水器から前記加圧流動床ボイラへ給水する給水系統とを備え、前記給水系統に、給水を加熱する排ガス熱交換器，給水加熱器および脱気器が設けられている加圧流動床複合発電プラントにおいて、
前記給水系統に、緊急停止時および起動停止時に排ガス・灰ク−ラ出口から排ガス熱交換器への置換水を供給する置換水供給系統を設けるとともに、この置換水供給系統に、供給置換水量を規定量に制御するため調節弁および流量計を設けたことを特徴とする加圧流動床複合発電プラント。A pressurized fluidized bed boiler for generating steam, a steam turbine driven by steam generated by the pressurized fluidized bed boiler, a gas turbine driven by combustion exhaust gas from the pressurized fluidized bed boiler, and the steam turbine And a water supply system for supplying water from the condenser to the pressurized fluidized-bed boiler, wherein the water supply system is provided with an exhaust gas heat exchanger for heating feedwater, a feedwater heater, and a deaerator. In a combined cycle power plant,
The water supply system is provided with a replacement water supply system for supplying replacement water from the exhaust gas / ash cooler outlet to the exhaust gas heat exchanger at the time of emergency stop and start / stop, and the replacement water supply system is provided with a supply replacement water amount. A combined pressurized fluidized-bed power plant comprising a control valve and a flow meter for controlling to a specified amount. 蒸気を発生させるボイラと、該ボイラで発生した蒸気により駆動される蒸気タービンと、燃焼ガスにより駆動されるガスタービンと、前記蒸気タービンで仕事をした蒸気を復水する復水器と、該復水器から前記ボイラへ給水する給水系統とを備え、前記給水系統は、前記復水器から供給される給水と前記ガスタービンの排ガスとを熱交換して前記給水を加熱する排ガス熱交換器と、該排ガス熱交換器から供給される給水を脱気する脱気器とを有する発電プラントにおいて、A boiler for generating steam, a steam turbine driven by the steam generated by the boiler, a gas turbine driven by combustion gas, a condenser for condensing the steam worked by the steam turbine, A water supply system for supplying water to the boiler from a water heater, wherein the water supply system exchanges heat between the water supplied from the condenser and the exhaust gas of the gas turbine and heats the water supply with an exhaust gas heat exchanger. A degasser for degassing feedwater supplied from the exhaust gas heat exchanger,
前記給水系統に、前記脱気器または脱気器出口側の給水を、前記排ガス熱交換器へ供給する給水供給系統を設けたことを特徴とする発電プラント。  A power plant, wherein the water supply system is provided with a water supply system for supplying the deaerator or the water on the outlet side of the deaerator to the exhaust gas heat exchanger.
JP32262997A 1997-11-25 1997-11-25 Pressurized fluidized bed combined cycle power plant and power plant Expired - Fee Related JP3604886B2 (en)

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