JP2004346945A - Steam temperature control method and device of combined cycle plant - Google Patents

Steam temperature control method and device of combined cycle plant Download PDF

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JP2004346945A
JP2004346945A JP2004233119A JP2004233119A JP2004346945A JP 2004346945 A JP2004346945 A JP 2004346945A JP 2004233119 A JP2004233119 A JP 2004233119A JP 2004233119 A JP2004233119 A JP 2004233119A JP 2004346945 A JP2004346945 A JP 2004346945A
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steam temperature
temperature
steam
superheater
reheater
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Takayuki Nagashima
嶋 孝 幸 長
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Toshiba Corp
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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
    • Y02E20/14—Combined heat and power generation [CHP]
    • 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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Abstract

<P>PROBLEM TO BE SOLVED: To reduce thermal stress generated in a steam turbine, by minimizing a difference between the superheater outlet steam temperature and the reheater outlet steam temperature, when starting a combined cycle plant. <P>SOLUTION: This control method of a uniaxial combined cycle plant, respectively controls the superheated steam temperature and the reheated steam temperature, by injecting spray water into desuperheaters 26 and 28. Opening of an inlet guide vane 1 of a gas turbine is adjusted by a deviation between the reheater inlet gas temperature and the superheater outlet steam temperature of an exhaust heat recovery boiler 8, to reduce a deviation of the outlet steam temperature between a reheater 10 and an superheater 9. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、ガスタービン、排熱回収ボイラ及び蒸気タービンから構成されるコンバインドサイクルプラントの蒸気温度制御方法及び制御装置に係り、特に過熱器、再熱器出口の蒸気温度の制御方法及び制御装置に関する。   The present invention relates to a method and a control device for controlling a steam temperature of a combined cycle plant including a gas turbine, an exhaust heat recovery boiler, and a steam turbine, and more particularly to a method and a control device for controlling a steam temperature at an outlet of a superheater and a reheater. .

近年発電設備の高効率化が要求されるとともに、環境対策の面でも優れているガスタービン・蒸気タービンコンバインドサイクルプラントが多く建設されるようになってきている。   In recent years, high efficiency of power generation equipment has been required, and many gas turbine / steam turbine combined cycle plants that are also excellent in environmental measures have been constructed.

上記ガスタービン・蒸気タービンコンバインドサイクルプラントは、ガスタービンの出力と蒸気タービンの出力によって発電機を駆動するようにしたものであって、ガスタービンの排ガスを排熱回収ボイラに導入し、そこで発生した蒸気を蒸気タービンに駆動用蒸気として導入するようにしてある。   The above-mentioned gas turbine / steam turbine combined cycle plant drives the generator by the output of the gas turbine and the output of the steam turbine, and introduces the exhaust gas of the gas turbine into the exhaust heat recovery boiler, which is generated there. The steam is introduced into the steam turbine as drive steam.

図４は、上記コンバインドサイクルプラントの概略構成を示す図であり、入口案内翼１を経て空気圧縮機２に吸入されて加圧された空気が燃焼器３に導入され、そこで燃料調節弁４を介して供給された燃料と混合・燃焼され１３００℃程度の高温高圧のガスが発生される。この高温高圧のガスはガスタービン５に流入し、そのガスタービン５を駆動し出力を発生し、このガスタービン５に後述する蒸気タービンとともに直結された発電機６を駆動し電力が発生される。   FIG. 4 is a diagram showing a schematic configuration of the combined cycle plant, in which air that is sucked into the air compressor 2 through the inlet guide vanes 1 and pressurized is introduced into the combustor 3, where the fuel control valve 4 is turned on. The fuel is mixed and burned with the fuel supplied through the fuel cell to generate a high-temperature and high-pressure gas of about 1300 ° C. The high-temperature, high-pressure gas flows into the gas turbine 5 and drives the gas turbine 5 to generate an output. The generator 6 directly connected to the gas turbine 5 together with a steam turbine described later generates electric power.

上記ガスタービン５の排ガスは排ガスダクト７によって排熱回収ボイラ８に導入され、上記排熱回収ボイラ８内に設けられている二次過熱器９、二次再熱器１０、一次再熱器１１、一次過熱器１２及び蒸発器１３を通り、さらに図示しない節炭器を経て約１００℃のガスとなって煙突から大気中に排出される。   The exhaust gas from the gas turbine 5 is introduced into an exhaust heat recovery boiler 8 by an exhaust gas duct 7, and a secondary superheater 9, a secondary reheater 10, and a primary reheater 11 provided in the exhaust heat recovery boiler 8 are provided. The gas passes through the primary superheater 12 and the evaporator 13 and further passes through a not-shown economizer to be converted into a gas at about 100 ° C. and discharged from the chimney into the atmosphere.

排熱回収ボイラ８では、上記ガスタービン５から導入された高温の大量の排ガスの熱によって蒸気が発生され、この蒸気が前記ガスタービン５と同軸的に連結されている蒸気タービン１４に供給される。すなわち、上記蒸発器１３で発生した蒸気がドラム１５で気水分離された後、一次過熱器１２で過熱され、この一次過熱器１２を出た蒸気は過熱器減温器１６でスプレー水と混合され二次過熱器出口蒸気温度が設定温度となるように減温調節された後、二次過熱器９を通り主蒸気管１７を経て高圧タービン１４ａに供給される。   In the exhaust heat recovery boiler 8, steam is generated by heat of a large amount of high-temperature exhaust gas introduced from the gas turbine 5, and the steam is supplied to a steam turbine 14 coaxially connected to the gas turbine 5. . That is, after the steam generated in the evaporator 13 is separated into steam and water by the drum 15, the steam is superheated by the primary superheater 12, and the steam exiting the primary superheater 12 is mixed with the spray water by the superheater desuperheater 16. Then, the temperature of the steam at the outlet of the secondary superheater is adjusted so as to be the set temperature, and then supplied to the high-pressure turbine 14 a through the secondary superheater 9 and the main steam pipe 17.

高圧タービン１４ａで膨張した蒸気は、低温再熱管１８を通り、一次再熱器１１に流入し、そこで再熱された蒸気は再熱器減温器１９でスプレー水と混合し再熱器出口蒸気温度が設定値となるように減温された後、二次再熱器１０に供給され再熱された後、さらに高温再熱管２０を経て中圧タービン１４ｂに供給される。   The steam expanded in the high-pressure turbine 14 a passes through the low-temperature reheat pipe 18 and flows into the primary reheater 11, where the reheated steam is mixed with spray water in the reheater desuperheater 19, and the reheater outlet steam After the temperature is reduced to the set value, it is supplied to the secondary reheater 10 and reheated, and further supplied to the intermediate pressure turbine 14b through the high temperature reheat pipe 20.

また主蒸気管１７には、蒸気温度が所定温度以上に上昇するまで、その蒸気を直接復水器２１に流入させるためのタービンバイパス導管２２が接続してあり、そのタービンバイパス導管２２にはタービンバイパス弁２３が設けられている。   The main steam pipe 17 is connected to a turbine bypass pipe 22 for allowing the steam to flow directly into the condenser 21 until the steam temperature rises to a predetermined temperature or higher. A bypass valve 23 is provided.

一方主蒸気管１７には主蒸気温度計２４及び主蒸気流量計２５が設けられており、図５に示すように、二次過熱器９の出口温度すなわち主蒸気温度計２４で検出された主蒸気温度と設定温度８０とを偏差器４０に入力し、この偏差器４０から偏差信号が出力される。この偏差信号と主蒸気流量計２５の入力値によって所定の信号が出力される信号発生器３６からの信号が加算器８１に入力されて加算される。この加算信号はＰＩＤ駆動装置３８、増幅器３９を介してスプレー水流量調節弁２６の制御部に入力される。そしてこの制御信号によって過熱器減温器１６に供給するスプレー水流量調節弁２６が制御されるようにしてある。また、図４に示すように高温再熱管２０には再熱蒸気温度計２７が設けられており、この再熱蒸気温度計２７で検出された再熱蒸気温度と設定温度との偏差によって再熱器減温器１９に供給するスプレー水流量調節弁２８が制御されるようにしてある。そして、各減温器に蒸気が流れていないときにスプレー水が注入されてしまうことを防止するため、主蒸気流量計２５で検出される主蒸気流量が或程度の量になったときに、調節弁２６、調節弁２８が制御されるようにしてある。   On the other hand, the main steam pipe 17 is provided with a main steam thermometer 24 and a main steam flow meter 25. As shown in FIG. 5, the main steam thermometer 24 detects the outlet temperature of the secondary superheater 9, that is, the main steam thermometer 24. The steam temperature and the set temperature 80 are input to the deviation device 40, and a deviation signal is output from the deviation device 40. A signal from the signal generator 36 that outputs a predetermined signal based on the deviation signal and the input value of the main steam flow meter 25 is input to the adder 81 and added. This addition signal is input to the control unit of the spray water flow control valve 26 via the PID drive device 38 and the amplifier 39. The control signal controls the spray water flow control valve 26 supplied to the superheater / temperature reducer 16. As shown in FIG. 4, a reheat steam thermometer 27 is provided in the high-temperature reheat pipe 20. The reheat steam is measured by a deviation between the reheat steam temperature detected by the reheat steam thermometer 27 and the set temperature. The spray water flow rate control valve 28 to be supplied to the heat reducing device 19 is controlled. Then, in order to prevent the spray water from being injected when steam is not flowing to each desuperheater, when the main steam flow rate detected by the main steam flow meter 25 becomes a certain amount, The control valves 26 and 28 are controlled.

ところで、近年の大容量、高温のガスタービンでは排ガス中に含まれるＮＯｘを低減するため、ガスタービンの排ガスを空気圧縮機の入口に再循環させる方法をとっているものが多い。また、コンバインドサイクルプラントの起動特性を最大限に発揮できるように、起動後ガスタービンの負荷を急速に上昇させる起動方法がとられるようになってきた。このため、図６に示すように、ガスタービンから排熱回収ボイラ（ＨＲＳＧ）に供給される排ガスの温度上昇率、流量上昇率も非常に大きくなり、二次過熱器の出口蒸気温度が急速に上昇するようになってきた。   In recent years, many large-capacity, high-temperature gas turbines adopt a method of recirculating exhaust gas from a gas turbine to an inlet of an air compressor in order to reduce NOx contained in the exhaust gas. Further, in order to maximize the startup characteristics of the combined cycle plant, a startup method for rapidly increasing the load on the gas turbine after startup has been adopted. For this reason, as shown in FIG. 6, the temperature rise rate and the flow rate rise rate of the exhaust gas supplied from the gas turbine to the exhaust heat recovery boiler (HRSG) become very large, and the outlet steam temperature of the secondary superheater rapidly increases. It is starting to rise.

また、ＮＯｘの排出を低減する燃焼方式を採用していることから、定格点での運転よりも、負荷が低い起動時の方がガスタービン出口ガス温度、つまり排熱回収ボイラの入口ガス温度が高いという排ガス特性をもつようになってきた。そこで、起動時はガス温度が常温から排ガスの最高温度６５０℃まで一気に上昇し、その後負荷上昇によって排ガス温度が低下してくるという運用がされるようになった。   In addition, since the combustion method that reduces NOx emissions is adopted, the gas turbine outlet gas temperature, that is, the inlet gas temperature of the exhaust heat recovery boiler, is lower at startup with a lower load than at the rated point. It has a high exhaust gas characteristic. Therefore, at the time of startup, the gas temperature rises from room temperature to the maximum temperature of the exhaust gas at 650 ° C. at a stretch, and thereafter, the exhaust gas temperature is decreased by the load increase.

したがって、このような運用がされた場合、排熱回収ボイラへ流入するガス温度の温度変化、流量の増大が大きいことから二次過熱器出口の蒸気温度も一気に上昇し、排熱回収ボイラ入口温度が定格点よりも上ってしまう状況では、図６の実線Ａに示すように、二次過熱器出口蒸気温度も定格点、最高使用温度をオーバーシュートしてしまうという問題がある。   Accordingly, when such an operation is performed, the temperature change of the gas flowing into the exhaust heat recovery boiler and the increase in the flow rate are large, so that the steam temperature at the outlet of the secondary superheater also rises at a stretch, and the exhaust heat recovery boiler inlet temperature When the temperature exceeds the rated point, as shown by the solid line A in FIG. 6, there is a problem that the secondary superheater outlet steam temperature also overshoots the rated point and the maximum operating temperature.

また、起動時にはガス温度が定格点よりも高くなるので、再熱器入口ガス温度もかなりの高温となる。しかも起動時に再熱器には蒸気が流されていないので、蒸気タービンの主蒸気加減弁が開き蒸気が再熱器に流入し、高温の再熱器で加熱される初期には、定格運転点よりもかなり高温の蒸気が中圧タービンに供給されることになる。したがって、互いに隣合った位置にある高圧蒸気の入口と中圧蒸気の入口との間に大きな温度差が発生する可能性があり、蒸気タービンの強度上の問題が発生する等の問題がある。   In addition, since the gas temperature becomes higher than the rated point at the time of starting, the gas temperature at the reheater inlet also becomes considerably high. In addition, since steam is not flowing to the reheater at startup, the main steam control valve of the steam turbine opens and the steam flows into the reheater, and in the initial period when the steam is heated by the high-temperature reheater, the rated operating point is reached. Steam much higher than that would be supplied to the medium pressure turbine. Therefore, there is a possibility that a large temperature difference may occur between the inlet of the high-pressure steam and the inlet of the medium-pressure steam which are located adjacent to each other, and there is a problem in that a problem in the strength of the steam turbine occurs.

本発明はこのような点に鑑み、コンバインドサイクルプラントの起動時における過熱器出口蒸気温度と再熱器出口蒸気温度の差を最小にして、蒸気タービンに発生する熱応力を低減するようにした蒸気温度制御方法及び装置を得ることを目的とする。   In view of the above, the present invention minimizes the difference between the superheater outlet steam temperature and the reheater outlet steam temperature during startup of a combined cycle plant, and reduces the thermal stress generated in the steam turbine. It is an object to obtain a temperature control method and device.

第１の発明は、過熱蒸気温度及び再熱蒸気温度をそれぞれ減温器にスプレー水を注入することにより制御するようにした一軸型コンバインドサイクルプラントの制御方法において、排熱回収ボイラの再熱器入口ガス温度と過熱器出口蒸気温度との偏差によってガスタービンの入口案内翼の開度を調整し、再熱器及び過熱器の出口蒸気温度の偏差を少なくするようにしたことを特徴とする。   A first invention provides a control method for a single-shaft combined cycle plant in which a superheated steam temperature and a reheated steam temperature are controlled by injecting spray water into a decooler, respectively. The opening degree of the inlet guide vanes of the gas turbine is adjusted based on the difference between the inlet gas temperature and the superheater outlet steam temperature, so that the deviation of the outlet steam temperature of the reheater and the superheater is reduced.

また、第２の発明は、過熱蒸気温度及び再熱蒸気温度をそれぞれ減温器にスプレー水を注入することにより制御するようにした一軸型コンバインドサイクルプラントの制御方法において、排熱回収ボイラの再熱器入口ガス温度と過熱器出口蒸気温度の偏差によって燃料弁を調節し、再熱器及び過熱器の出口蒸気温度の偏差を少なくするようにしたことを特徴とする。   Further, a second invention provides a control method of a single-shaft combined cycle plant in which a superheated steam temperature and a reheated steam temperature are controlled by injecting spray water into a desuperheater, respectively. The fuel valve is adjusted according to the difference between the gas temperature at the inlet of the heater and the steam temperature at the outlet of the superheater, so that the difference between the steam temperatures at the outlet of the reheater and the superheater is reduced.

再熱器入口ガス温度と過熱器出口蒸気温度との差によってガスタービンの入口案内翼或は燃料流量調節弁を制御するようにしたので、主蒸気加減弁の開時に主蒸気温度と再熱蒸気温度の温度差を最小にすることができ、蒸気タービンに発生する熱応力を最小に抑えることができる。   Since the inlet guide vanes of the gas turbine or the fuel flow control valve is controlled by the difference between the reheater inlet gas temperature and the superheater outlet steam temperature, the main steam temperature and the reheat steam are controlled when the main steam control valve is opened. The temperature difference between the temperatures can be minimized, and the thermal stress generated in the steam turbine can be minimized.

以下、添付図面を参照して本発明の実施の形態について説明する。
図４に示すようなプラントにおいて、ガスタービン５が起動されると高温の排ガスが排熱回収ボイラ８に流入し、排熱回収ボイラ入口ガス温度が急速に上昇し始める。これによって蒸発器１３で蒸気が発生し始める。そして、ここで発生した蒸気は一次過熱器１２及び二次過熱器９で過熱されるが、この時点では未だ蒸気タービンに通気するには温度が低いため、蒸気温度が一定に上昇するまでの間は主蒸気管１７及びタービンバイパス導管２２を介して蒸気タービン１４をバイパスして蒸気が直接復水器２１に排出される。 Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
In the plant as shown in FIG. 4, when the gas turbine 5 is started, high-temperature exhaust gas flows into the exhaust heat recovery boiler 8, and the gas temperature at the exhaust heat recovery boiler starts to rise rapidly. As a result, steam starts to be generated in the evaporator 13. Then, the steam generated here is superheated by the primary superheater 12 and the secondary superheater 9, but at this time, the temperature is still low to ventilate the steam turbine. The steam is directly discharged to the condenser 21 by bypassing the steam turbine 14 via the main steam pipe 17 and the turbine bypass conduit 22.

その後ガスタービン５が徐々に負荷をとってくると、排熱回収ボイラ入口ガス流量、ガス温度が更に急上昇を続ける。発生蒸気量が一定値に達すると蒸発器１３での蒸発が安定して行われるようになり、各部の弁の開度も安定してくる。そして、排熱回収ボイラ入口ガス温度の上昇によって過熱器出口蒸気温度も上昇し、蒸気タービンに蒸気を通気できる条件が整う。ここで、主蒸気加減弁２９が開き、蒸気タービン１４に蒸気が導入される。   Thereafter, when the gas turbine 5 gradually takes on the load, the gas flow rate at the inlet of the exhaust heat recovery boiler and the gas temperature continue to rise sharply. When the amount of generated steam reaches a certain value, the evaporation in the evaporator 13 is performed stably, and the opening of the valve of each part also becomes stable. Then, the temperature of the steam at the superheater outlet also rises due to the rise in the gas temperature at the exhaust heat recovery boiler inlet, and the conditions for ventilating the steam into the steam turbine are established. Here, the main steam control valve 29 is opened, and steam is introduced into the steam turbine 14.

ところで、排熱回収ボイラ８の二次過熱器９の入口側には、排熱回収ボイラ入口ガス温度計３０が設けられており、排熱回収ボイラ８に流入するガス温度が検出されている。また、図４に示すように排熱回収ボイラ８の二次再熱器１０の入口側には二次再熱器入口ガス温度計４１が設けられている。   By the way, on the inlet side of the secondary superheater 9 of the exhaust heat recovery boiler 8, an exhaust heat recovery boiler inlet gas thermometer 30 is provided, and the temperature of the gas flowing into the exhaust heat recovery boiler 8 is detected. As shown in FIG. 4, a secondary reheater inlet gas thermometer 41 is provided on the inlet side of the secondary reheater 10 of the exhaust heat recovery boiler 8.

そこで、前述のようにガスタービンが起動された後未だ蒸気タービンに蒸気を通気できない時点には、蒸気はタービンバイパス弁２３を介して復水器２１に排出されているので、二次再熱器１０及び一次再熱器１１には蒸気が全く流れていない。そして、この状態のときにガスタービンの負荷が徐々に上昇すると排ガス温度が上昇し排熱回収ボイラ入口ガス温度が二次過熱器出口蒸気温度の５４１℃を越えて６００℃程度まで上昇する。   Therefore, at the time when the steam cannot be passed through the steam turbine after the gas turbine is started as described above, the steam is discharged to the condenser 21 through the turbine bypass valve 23. No steam is flowing through 10 and primary reheater 11. In this state, when the load on the gas turbine gradually increases, the exhaust gas temperature rises, and the exhaust gas heat recovery boiler inlet gas temperature rises to about 600 ° C., exceeding the secondary superheater outlet steam temperature of 541 ° C.

しかし、蒸気流量はまだ少なく、二次過熱器９でのガス温度の低下は少なく、この結果図２に示すように、二次再熱器入口の排ガス温度が過熱器出口蒸気温度の設定値の５４１℃を越えてしまうこととなる。そして、このとき再熱器には蒸気が全く流れていないので再熱器の伝熱管のメタル温度はほぼこの二次再熱器入口ガス温度と同一の温度となってしまう。   However, the steam flow rate is still small, and the gas temperature in the secondary superheater 9 does not decrease much. As a result, as shown in FIG. 2, the exhaust gas temperature at the secondary reheater inlet is lower than the set value of the superheater outlet steam temperature. It will exceed 541 ° C. Then, at this time, since no steam flows through the reheater, the metal temperature of the heat transfer tube of the reheater is almost the same as the gas temperature at the inlet of the secondary reheater.

しかして、この状態で主蒸気加減弁２９が開き、蒸気が高圧タービンを介して二次再熱器１０に流入すると、二次再熱器１０の出口の蒸気温度は一次的にこの時の二次再熱器入口ガス温度と同一の温度となって中圧タービン１４ｂ（再熱タービン）に流入する。ところが、この時主蒸気温度は前述のように５４１℃以下に制御されているので、主蒸気温度と再熱蒸気温度の間には４０〜５０℃程度の差が発生し、蒸気タービンに過大な熱応力が発生する。   In this state, when the main steam control valve 29 is opened and the steam flows into the secondary reheater 10 through the high-pressure turbine, the steam temperature at the outlet of the secondary reheater 10 is temporarily changed to the secondary temperature at this time. The temperature becomes the same as the gas temperature at the inlet of the next reheater and flows into the intermediate pressure turbine 14b (reheat turbine). However, at this time, since the main steam temperature is controlled to 541 ° C or lower as described above, a difference of about 40 to 50 ° C occurs between the main steam temperature and the reheat steam temperature, and an excessive Thermal stress occurs.

図１はその対策としての実施の形態の制御系統図であり、図４に示すように、排熱回収ボイラ８の二次再熱器１０の入口側には二次再熱器入口ガス温度計４１が設けられている。そこで、主蒸気温度計２４で検出された主蒸気温度すなわち二次過熱器出口蒸気温度と、二次再熱器入口ガス温度計４１で検出された二次再熱器入口ガス温度が偏差器４２に入力され、その偏差信号がＰＩＤ制御装置４３及び増幅器４４を経てガスタービンの入口案内翼アクチュエーター４５に入力され、そのアクチュエーター４５によって入口案内翼１の開度が制御されるようにしてある。   FIG. 1 is a control system diagram of an embodiment as a countermeasure, and as shown in FIG. 4, a secondary reheater inlet gas thermometer is provided on the inlet side of the secondary reheater 10 of the exhaust heat recovery boiler 8. 41 are provided. Therefore, the main steam temperature detected by the main steam thermometer 24, that is, the secondary superheater outlet steam temperature, and the secondary reheater inlet gas temperature detected by the secondary reheater inlet gas thermometer 41 are differentiator 42. The deviation signal is input to the inlet guide blade actuator 45 of the gas turbine via the PID controller 43 and the amplifier 44, and the actuator 45 controls the opening degree of the inlet guide blade 1.

入口案内翼１は空気圧縮機に流入する空気流量を調節する機能を有する案内翼であり、その入口案内翼を開くとガス流量が増加し、ガスタービン出口の排ガス温度が低下する。また、入口案内翼を閉じるとガス流量が減少して排ガス温度が上昇する特性を示す。   The inlet guide vanes 1 are guide vanes having a function of adjusting the flow rate of air flowing into the air compressor. When the inlet guide vanes are opened, the gas flow rate increases, and the exhaust gas temperature at the gas turbine outlet decreases. Further, when the inlet guide vane is closed, the gas flow rate decreases and the exhaust gas temperature increases.

しかして、二次再熱器１０の入口ガス温度が二次過熱器出口蒸気温度よりも高くなると、この偏差信号によって入口案内翼１が開方向に制御される。したがって、ガスタービンの排ガス温度が低下され、二次再熱器入口ガス温度が二次過熱器出口蒸気温度と同一の温度となるように制御される。そこで、主蒸気加減弁２９が開いて蒸気が蒸気タービンに流入し、二次再熱器にも蒸気が流入開始すると、二次再熱器からは二次過熱器出口蒸気とほぼ同一温度の蒸気が流出する。   Thus, when the inlet gas temperature of the secondary reheater 10 becomes higher than the secondary superheater outlet steam temperature, the deviation guide signal controls the inlet guide vane 1 in the opening direction. Therefore, the exhaust gas temperature of the gas turbine is reduced, and the secondary reheater inlet gas temperature is controlled to be the same as the secondary superheater outlet steam temperature. Then, when the main steam control valve 29 is opened and the steam flows into the steam turbine and the steam starts to flow into the secondary reheater, the steam having almost the same temperature as the steam at the outlet of the secondary superheater is output from the secondary reheater. Leaks out.

したがって、主蒸気加減弁の開動作時に主蒸気温度と再熱蒸気温度との温度差が最小にでき、蒸気タービンに発生する熱応力を最小に抑えることが可能となる。   Therefore, the temperature difference between the main steam temperature and the reheat steam temperature during the opening operation of the main steam control valve can be minimized, and the thermal stress generated in the steam turbine can be minimized.

また、上記実施の形態においてはガスタービンの入口案内翼１の開度を制御するものを示したが、図３に示すように、燃料調節弁４を制御して燃料の流量を絞ってガス温度を低下させることによっても同様の効果を奏させることができる。   Further, in the above-described embodiment, the opening degree of the inlet guide vane 1 of the gas turbine is controlled. However, as shown in FIG. A similar effect can also be achieved by reducing.

本発明の実施の形態を示す制御系統図。FIG. 1 is a control system diagram showing an embodiment of the present invention. 排ガス温度と蒸気温度の関係を示す図。The figure which shows the relationship between exhaust gas temperature and steam temperature. 本発明の他の実施の形態を示す制御系統図。The control system figure which shows other embodiment of this invention. コンバインドサイクルプラントの概略系統図。FIG. 1 is a schematic system diagram of a combined cycle plant. 従来のスプレー水流量制御装置の系統図。The system diagram of the conventional spray water flow control device. 起動時の排ガス温度と蒸気温度、スプレー水量を示す図。The figure which shows the exhaust gas temperature at the time of starting, a steam temperature, and a spray water amount.

符号の説明Explanation of reference numerals

１ 入口案内翼
２ 空気圧縮機
３ 燃焼器
４ 燃料調節弁
５ ガスタービン
６ 発電機
８ 排熱回収ボイラ
９ 二次過熱器
１０ 二次再熱器
１３ 蒸発器
１４ 蒸気タービン
１６ 過熱器減温器
１９ 再熱器減温器
２４ 主蒸気温度計
２５ 主蒸気流量計
２６、２８ スプレー水流量調節弁
４１ 二次再熱器入口ガス温度計
４５ ガスタービンの入口案内翼アクチュエーター DESCRIPTION OF SYMBOLS 1 Inlet guide blade 2 Air compressor 3 Combustor 4 Fuel control valve 5 Gas turbine 6 Generator 8 Waste heat recovery boiler 9 Secondary superheater 10 Secondary reheater 13 Evaporator 14 Steam turbine 16 Superheater desuperheater 19 Reheater desuperheater 24 Main steam thermometer 25 Main steam flow meter 26, 28 Spray water flow control valve 41 Secondary reheater inlet gas thermometer 45 Gas turbine inlet guide blade actuator

Claims (4)

過熱蒸気温度及び再熱蒸気温度をそれぞれ減温器にスプレー水を注入することにより制御するようにした一軸型コンバインドサイクルプラントの制御方法において、排熱回収ボイラの再熱器入口ガス温度と過熱器出口蒸気温度との偏差によってガスタービンの入口案内翼の開度を調整し、再熱器及び過熱器の出口蒸気温度の偏差を少なくするようにしたことを特徴とする、コンバインドサイクルプラントの蒸気温度制御方法。   In a control method for a single-shaft combined cycle plant in which a superheated steam temperature and a reheated steam temperature are controlled by injecting spray water into a desuperheater, respectively, a reheater inlet gas temperature of a waste heat recovery boiler and a superheater The steam temperature of a combined cycle plant, wherein the opening degree of the inlet guide vanes of the gas turbine is adjusted according to the deviation from the outlet steam temperature to reduce the deviation of the outlet steam temperature of the reheater and superheater. Control method. 過熱蒸気温度及び再熱蒸気温度をそれぞれ減温器にスプレー水を注入することにより制御するようにした一軸型コンバインドサイクルプラントの制御方法において、排熱回収ボイラの再熱器入口ガス温度と過熱器出口蒸気温度の偏差によって燃料弁を調節し、再熱器及び過熱器の出口蒸気温度の偏差を少なくするようにしたことを特徴とする、コンバインドサイクルプラントの蒸気温度制御方法。   In a control method for a single-shaft combined cycle plant in which a superheated steam temperature and a reheated steam temperature are controlled by injecting spray water into a desuperheater, respectively, a reheater inlet gas temperature of a waste heat recovery boiler and a superheater A steam temperature control method for a combined cycle plant, wherein a fuel valve is adjusted according to a difference in outlet steam temperature to reduce a difference in outlet steam temperature of a reheater and a superheater. 排熱回収ボイラ出口の過熱蒸気温度を過熱器減温器でスプレー水を注入することにより制御するようにした一軸型コンバインドサイクルプラントの蒸気温度制御装置において、再熱器入口ガス温度計と、過熱器出口蒸気温度計と、上記両温度計で検出された温度信号を比較し、その偏差信号をガスタービンの入口案内翼に制御信号として出力する偏差器とを有することを特徴とする、コンバインドサイクルプラントの蒸気温度制御装置。   In a single-shaft combined cycle plant steam temperature control device that controls the superheated steam temperature at the exhaust heat recovery boiler outlet by injecting spray water with a superheater desuperheater, a reheater inlet gas thermometer and superheater A combined cycle, comprising a steam outlet thermometer and a deviator for comparing temperature signals detected by the two thermometers and outputting a deviation signal as a control signal to an inlet guide vane of the gas turbine. Plant steam temperature controller. 排熱回収ボイラ出口の過熱蒸気温度を過熱器減温器でスプレー水を注入することにより制御するようにした一軸型コンバインドサイクルプラントの蒸気温度制御装置において、再熱器入口ガス温度計と、過熱器出口蒸気温度計と、上記両温度計で検出された温度を比較し、その信号をガスタービンの燃料調節弁に制御信号として出力する偏差器とを有することを特徴とする、コンバインドサイクルプラントの蒸気温度制御装置。   In a single-shaft combined cycle plant steam temperature control device that controls the superheated steam temperature at the exhaust heat recovery boiler outlet by injecting spray water with a superheater desuperheater, a reheater inlet gas thermometer and superheater A combined cycle plant having a steam outlet thermometer and a deviator for comparing the temperatures detected by the two thermometers and outputting the signal as a control signal to a fuel control valve of the gas turbine. Steam temperature control device.
JP2004233119A 2004-08-10 2004-08-10 Steam temperature control method and device of combined cycle plant Pending JP2004346945A (en)

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JPH01285608A (en) * 1988-05-11 1989-11-16 Hitachi Ltd Method and device of operating combined plant
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Publication number Priority date Publication date Assignee Title
JP2015227630A (en) * 2014-05-30 2015-12-17 株式会社東芝 Plant controller and plant activation method

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