CN114837810B - Method and system for improving wide-load operation control efficiency of gas-steam combined cycle peak shaver set - Google Patents
Method and system for improving wide-load operation control efficiency of gas-steam combined cycle peak shaver set Download PDFInfo
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- CN114837810B CN114837810B CN202210578513.5A CN202210578513A CN114837810B CN 114837810 B CN114837810 B CN 114837810B CN 202210578513 A CN202210578513 A CN 202210578513A CN 114837810 B CN114837810 B CN 114837810B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
- F02C6/00—Plural gas-turbine plants; Combinations of gas-turbine plants with other apparatus; Adaptations of gas-turbine plants for special use
- F02C6/18—Plural gas-turbine plants; Combinations of gas-turbine plants with other apparatus; Adaptations of gas-turbine plants for special use using the waste heat of gas-turbine plants outside the plants themselves, e.g. gas-turbine power heat plants
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
- F02C6/00—Plural gas-turbine plants; Combinations of gas-turbine plants with other apparatus; Adaptations of gas-turbine plants for special use
- F02C6/14—Gas-turbine plants having means for storing energy, e.g. for meeting peak loads
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
- F02C9/00—Controlling gas-turbine plants; Controlling fuel supply in air- breathing jet-propulsion plants
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
- F22B33/00—Steam-generation plants, e.g. comprising steam boilers of different types in mutual association
- F22B33/18—Combinations of steam boilers with other apparatus
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22G—SUPERHEATING OF STEAM
- F22G3/00—Steam superheaters characterised by constructional features; Details or component parts thereof
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22G—SUPERHEATING OF STEAM
- F22G5/00—Controlling superheat temperature
- F22G5/12—Controlling superheat temperature by attemperating the superheated steam, e.g. by injected water sprays
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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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Abstract
The invention discloses a method and a system for improving the efficiency of wide-load operation control of a gas-steam combined cycle peak shaver set, wherein the method comprises the following steps: the final-stage reheater is arranged on the first-stage heating surface and is nearest to the outlet of the combustion engine, so that the final-stage reheater directly bears the scouring of high-temperature flue gas; upgrading the final reheater material of the waste heat boiler to adapt to higher outlet steam temperature of the waste heat boiler; the high-pressure superheater de-superheated water is extracted from the outlet of the high-pressure feed pump and is extracted from the interstage of the high-pressure economizer, so that the parameters of the high-pressure main steam outlet are improved; operating the gas-steam combined cycle unit by utilizing the air with the temperature increased; the invention utilizes the characteristic of high partial load exhaust temperature of the gas turbine, can improve the outlet steam parameter of the waste heat boiler (equivalent to the improvement of the primary parameter of the inlet of the steam turbine) by adjusting the arrangement of the heating surface of the waste heat boiler, is beneficial to improving the efficiency of a unit, and can obtain larger system efficiency improvement by improving the reheat steam temperature ratio and the high-pressure main steam temperature.
Description
Technical Field
The invention relates to the technical field of power generation of a gas-steam combined cycle unit, in particular to a method and a system for improving the efficiency of wide-load operation control of a gas-steam combined cycle peak shaver unit.
Background
The natural gas peak regulation power station has the characteristics of partial load operation in most of time and lower annual utilization hours of a unit. In order to make the peak shaving power station benefit higher, it is obvious that the efficiency of the host machine needs to be improved, and the efficiency is the efficiency under the partial load working condition. Some improvement schemes are proposed by existing host manufacturers, such as air compressor air intake heating, namely low-grade hot water of a waste heat boiler is utilized, a heat exchange coil for heating air is arranged in an air intake chamber of an air intake system, the temperature of air entering the air compressor is heated through heat exchange with air intake, hot water from a low-pressure economizer and condensed water from a condenser are mixed according to a certain proportion, the mixed water reaches the required temperature and flow, the mixed water enters a coil heat exchanger, air exchanges heat, the air temperature is increased, and outlet water flows back into the condensed water. The temperature and pressure of hot water from a low-pressure economizer, condensed water from a condenser, mixed coil water inlet and coil water outlet are monitored, and the water inlet flow is controlled through the temperature end difference of the water side, so that the following defects exist in the above technology:
1. Additional heat exchangers (coil heat exchangers), water pumps and the like are needed to be added to realize water side circulation, so that initial investment is increased, and resistance of an air inlet system is increased;
2. The heat exchange amount of the low-pressure economizer is increased, the heat exchange area of the low-pressure economizer is also required to be increased, and the initial investment of the waste heat boiler body is increased;
3. in order to control the flow of the condensed water and the hot water of the low-pressure economizer, two sets of regulating valve groups are required to be respectively arranged on two systems, so that initial investment is increased, the system control is complex, and the reliability is reduced;
4. As the intake air temperature increases, the amount of water drawn from the low-pressure economizer increases, and the exhaust temperature of the exhaust-heat boiler gradually decreases. Considering the safety of the heating surface at the tail of the boiler, the inlet air temperature is not suitable to be heated too high, so that the benefit of the method is very little;
5. The application range is small, the lower the unit load is, the improvement of efficiency after the air inlet heating operation is obvious, so that the prior art has defects and needs to be improved.
Disclosure of Invention
Aiming at the defects existing in the prior art, the invention aims to provide a method and a system for improving the efficiency of the wide-load operation control of a gas-steam combined cycle peak shaver set, so as to solve the problems in the background art. In order to achieve the above purpose, the present invention adopts the following technical scheme: a method and a system for improving the efficiency of the wide-load operation control of a gas-steam combined cycle peak shaver set are provided, wherein the method comprises the following steps:
acquiring a real power value and a target power value of the gas-steam combined cycle unit;
Raising the temperature of air entering an air inlet of an air inlet module of the gas-steam combined cycle unit;
According to the deviation between the actual power value and the target load value, controlling the load of the gas turbine to enable the actual power value to be consistent with the target load value;
The final-stage reheater is arranged on the first-stage heating surface and is nearest to the outlet of the combustion engine, so that the final-stage reheater directly bears the scouring of high-temperature flue gas;
Upgrading the final reheater material of the waste heat boiler to adapt to higher outlet steam temperature of the waste heat boiler;
The high-pressure superheater de-superheated water is extracted from the outlet of the high-pressure feed pump and is extracted from the interstage of the high-pressure economizer, so that the parameters of the high-pressure main steam outlet are improved;
and operating the gas-steam combined cycle unit by utilizing the air after the temperature is raised.
Preferably, the method further comprises:
According to the actual running condition of the gas-steam combined cycle unit, correcting the load proportion of the gas turbine, the waste heat boiler and the steam turbine;
And automatically calculating the load change rate of the gas-steam combined cycle unit according to the load change rate upper limit, the load change rate lower limit, the exhaust temperature and the steam turbine cylinder temperature change rate of the gas turbine, and controlling synchronous load lifting of the gas turbine and the steam turbine according to the load change rate.
Preferably, the method further comprises:
And controlling cold start, warm start, hot start and sequential control start and stop with breakpoint confirmation under normal stop working conditions of the steam turbine, and controlling diffusion combustion, mixed combustion and load rising rate of the gas turbine under premixed combustion working conditions.
Preferably, the method further comprises: and calculating the maximum load capacity values which can be born by the gas-steam combined cycle unit under different operation conditions, and improving the steam parameters of the reheating system of the gas-steam combined cycle unit under different operation conditions.
Preferably, the method further comprises: and controlling the output temperature of the final-stage reheater of the waste heat boiler to be matched with the load capacity value of the gas-steam combined cycle unit.
Preferably, the system comprises:
the load value acquisition unit is used for acquiring the real power value and the target power value of the gas-steam combined cycle unit;
A load control unit for controlling the load of the gas turbine according to the deviation between the actual power value and the target load value, so that the actual power value is consistent with the target load value;
preferably, the system further comprises:
the load distribution unit is used for correcting the load proportion of the gas turbine, the waste heat boiler and the steam turbine according to the actual running condition of the gas-steam combined cycle unit;
A load change rate calculation unit for automatically calculating the load change rate of the gas-steam combined cycle unit according to the load change rate upper limit, the load change rate lower limit, the exhaust temperature and the steam turbine cylinder temperature change rate of the gas turbine,
Wherein the load control unit controls synchronous load rise of the gas turbine and the steam turbine according to the load change rate.
Preferably, the system further comprises: the two-stage high-pressure and high-temperature reheating system is divided into an interstage temperature reduction system and a final-stage temperature reduction system respectively, and the interstage temperature reduction system is used for controlling the temperature of steam entering the final-stage superheater and the reheater inlet, but because the difference between the exhaust temperature of the fuel engine and the temperature of high-pressure main steam and the temperature of the high-temperature reheating is too large, and meanwhile, in order to ensure the superheat degree of the steam entering the final-stage high-pressure superheater and the reheater, the interstage temperature reduction is often unable to reach the steam inlet temperature required by the steam engine during starting, so the high-pressure superheater and the reheater final-stage temperature reduction system are arranged.
Preferably, the system further comprises: the desuperheating water of the reheater stage and the final-stage desuperheating system is pumped by an outlet pipeline of the medium-pressure water supply pump, and enters the desuperheater pipeline through a desuperheater regulating valve and a desuperheater nozzle, the desuperheating water of the high-pressure stage and the final-stage desuperheating system is pumped by a traditional outlet pipeline of the high-pressure water supply pump, and is controlled to be pumped from an outlet of the high-pressure economizer 2, and enters the desuperheater pipeline through the desuperheater regulating valve and the desuperheater nozzle.
And the final control unit of the waste heat boiler is used for controlling the output temperature of the final reheater of the waste heat boiler and is matched with the load capacity value of the gas-steam combined cycle unit.
Preferably, the system further comprises: and the sequential control start-stop unit is used for controlling the sequential control start-stop with breakpoint confirmation under the working conditions of cold start, warm start, hot start and normal stop of the steam turbine and controlling the diffusion combustion, the mixed combustion and the load rising rate of the gas turbine under the working conditions of premixed combustion.
Preferably, the system further comprises: the unit load capacity calculation unit is used for calculating each maximum load capacity value which can be born by the gas-steam combined cycle unit under different operation conditions, and limiting the load of the gas-steam combined cycle unit under different operation conditions to the corresponding maximum load capacity value.
Preferably, the system further comprises: the method realizes the improvement of the reheat steam temperature through the combustion adjustment of the gas turbine, the optimization of the arrangement mode and the temperature reduction mode of the heating surface of the waste heat boiler, the upgrading of the materials of the heat parts of the gas turbine, the application of new materials of related thermodynamic systems and the optimization of an intelligent control system, thereby improving the power generation efficiency of a unit.
Compared with the prior art, the invention has the beneficial effects that by adopting the scheme, the final-stage reheater can be arranged on the first-stage heating surface by adjusting the arrangement of the heating surface of the waste heat boiler by utilizing the characteristic that the gas turbine has higher partial load smoke discharging temperature; steam parameters of the reheating system are improved under the partial load working condition, so that the efficiency of the combined cycle unit is improved; material upgrading is performed to adapt to steam parameters of a reheating system with higher parameters; the design of the temperature reducing water system is improved to adapt to a high-parameter thermodynamic system.
Drawings
FIG. 1 is a flow chart of a control method according to an embodiment of the present invention;
FIG. 2 is a flow chart of a method for controlling the load of a gas turbine to match the actual power value with the target load value according to the deviation between the actual power value and the target load value in the control method of the embodiment of FIG. 1 according to the present invention;
FIG. 3 is a schematic flow chart of a method for upgrading the final reheater material of a waste heat boiler to accommodate a higher outlet steam temperature step of the waste heat boiler of the embodiment of FIG. 1;
Fig. 4 is a schematic block diagram of a control system according to the embodiment of fig. 1.
Detailed Description
In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings.
In the description of the present specification, the descriptions of the terms "embodiment," "one embodiment," and the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or embodiment is included in at least one embodiment or illustrated embodiment of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same examples or implementations. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or implementations.
As shown in fig. 1-3, one embodiment of the present invention is,
1. The method and the system for improving the wide-load operation control efficiency of the gas-steam combined cycle peak shaver set are characterized by comprising the following steps:
S1, acquiring a real power value and a target power value of the gas-steam combined cycle unit;
s2, raising the temperature of air entering an air inlet of an air inlet module of the gas-steam combined cycle unit;
S3, controlling the load of the gas turbine according to the deviation of the actual power value and the target load value, so that the actual power value is consistent with the target load value;
s4, upgrading the final-stage reheater material of the waste heat boiler to adapt to the higher outlet steam temperature of the waste heat boiler;
S5, operating the gas-steam combined cycle unit by utilizing the air with the temperature increased.
The step S3 further includes:
s31, correcting the load proportion of the gas turbine, the waste heat boiler and the steam turbine according to the actual running condition of the gas-steam combined cycle unit;
S32, automatically calculating the load change rate of the gas-steam combined cycle unit according to the load change rate upper limit, the load change rate lower limit, the exhaust temperature and the steam turbine cylinder temperature change rate of the gas turbine, and controlling synchronous load lifting of the gas turbine and the steam turbine according to the load change rate.
S33, controlling the cold start, the warm start, the hot start and the sequential control start and stop with breakpoint confirmation under normal stop working conditions of the steam turbine, and controlling the diffusion combustion, the mixed combustion and the load rising rate of the gas turbine under premixed combustion working conditions.
The step S32 further includes:
S321, calculating the maximum load capacity values which can be borne by the gas-steam combined cycle unit under different operation conditions, and improving the steam parameters of the reheating system of the gas-steam combined cycle unit under different operation conditions.
The step S4 further includes:
S41, controlling the output temperature of the final reheater of the waste heat boiler to be matched with the load capacity value of the gas-steam combined cycle unit.
As shown in fig. 4, the gas-steam combined cycle unit control system includes:
the load value acquisition unit is used for acquiring the real power value and the target power value of the gas-steam combined cycle unit;
A load control unit for controlling the load of the gas turbine according to the deviation between the actual power value and the target load value, so that the actual power value is consistent with the target load value;
The system further comprises:
the load distribution unit is used for correcting the load proportion of the gas turbine, the waste heat boiler and the steam turbine according to the actual running condition of the gas-steam combined cycle unit;
A load change rate calculation unit for automatically calculating the load change rate of the gas-steam combined cycle unit according to the load change rate upper limit, the load change rate lower limit, the exhaust temperature and the steam turbine cylinder temperature change rate of the gas turbine,
Wherein the load control unit controls synchronous load rise of the gas turbine and the steam turbine according to the load change rate.
The system further comprises:
And the final control unit of the waste heat boiler is used for controlling the output temperature of the final reheater of the waste heat boiler and is matched with the load capacity value of the gas-steam combined cycle unit.
The system further comprises: and the sequential control start-stop unit is used for controlling the sequential control start-stop with breakpoint confirmation under the working conditions of cold start, warm start, hot start and normal stop of the steam turbine and controlling the diffusion combustion, the mixed combustion and the load rising rate of the gas turbine under the working conditions of premixed combustion.
The system further comprises: the unit load capacity calculation unit is used for calculating each maximum load capacity value which can be born by the gas-steam combined cycle unit under different operation conditions, and limiting the load of the gas-steam combined cycle unit under different operation conditions to the corresponding maximum load capacity value.
Furthermore, due to the fact that the high-temperature reheat steam parameters are improved, the material selection of reheat steam, bypass steam, drainage and other systems is affected, and the design of a reheater temperature reduction water system in a water supply system is also affected.
The choice of pipe material depends primarily on the media parameters. In the conventional scheme, the design temperature of the high-temperature reheat steam, the intermediate-pressure bypass valve front steam and the related drain pipelines of the F-stage gas-steam combined cycle unit is generally 572 ℃, so that the pipeline made of P91 material (the recommended use limit temperature is 593 ℃) can be adopted. In the high-performance scheme, the temperature of the high-temperature reheat steam pipeline is increased to 605 ℃ under the partial load working condition, the design temperature reaches 610 ℃, and the pipeline made of the P91 material can be still used, but the wall thickness of the pipeline is greatly increased due to the fact that the allowable stress of the material is reduced due to the fact that the temperature is increased. For a unit with heavy peak shaving tasks, the excessive wall thickness of a steam-water pipeline influences the load changing rate of the unit, and fatigue failure of the pipe is also a big problem. Meanwhile, it was found in the early 1990 s that P91 steel could not meet the requirement of long-term safe operation when the use temperature exceeded 600 c on the basis of mass popularization of P91 steel. Therefore, the pipeline materials are needed to be reselected so as to adapt to the frequent start-stop working condition of the peak shaver set and ensure the safety of long-term operation of the set;
In order to control the outlet temperatures of the high-pressure main steam and the hot re-main steam to match the starting parameters of the steam turbine, the project is provided with two stages of high-pressure and reheating temperature reduction systems. The high-pressure and reheating two-stage temperature reducing system is divided into an interstage temperature reducing system and a final stage temperature reducing system respectively. The purpose of the interstage attemperation system is to control the temperature of the steam entering the final superheater, reheater inlet. However, because the exhaust temperature of the gas turbine and the difference between the high-pressure main steam and the hot re-temperature are too large, and meanwhile, in order to ensure the superheat degree of steam entering the final-stage high-pressure superheater and the reheater, the interstage temperature reduction often cannot reach the steam inlet temperature required by the gas turbine during starting, so that a final-stage temperature reduction system of the high-pressure superheater and the reheater is arranged;
in the project, the desuperheating water of the inter-stage and final-stage desuperheating systems of the reheater is pumped by an outlet pipeline of a medium-pressure water supply pump, and enters a desuperheater pipeline after passing through a desuperheater regulating valve and a desuperheater nozzle. The desuperheating water of the high-pressure interstage and final-stage desuperheating system is extracted from the outlet pipeline of the high-pressure water feeding pump by the traditional method, is regulated to be extracted from the outlet of the high-pressure economizer 2, and enters the desuperheater pipeline through a desuperheater regulating valve and a desuperheater spray head. Thus, not only the temperature reduction requirement is met, but also the high-pressure main steam flow is increased, so that the parameters of each system are matched with a thermal equilibrium diagram under the working conditions of 100% and 75% pure condensation of the performance of the boiler;
The reheating steam temperature is improved through comprehensive measures such as combustion adjustment of a gas turbine, optimization of a heating surface arrangement mode and a temperature reduction mode of a waste heat boiler, upgrading of materials of heat parts of the gas turbine, application of new materials of related thermodynamic systems, optimization of an intelligent control system and the like, so that the power generation efficiency of a unit is improved
The invention is applied to the gas-steam combined cycle unit, and reasonably compensates the difference of the load change speed of the gas turbine and the load change speed of the steam turbine by automatically adjusting the load distribution of the gas turbine and the steam turbine, thereby optimizing the running mode of the unit, ensuring the safe running of the unit, reducing the operation amount of operators, effectively reducing the unplanned shutdown times caused by misoperation of the operators, and indirectly creating certain economic benefit.
Preferably, according to a large amount of design experience of the combined cycle power plant, the end difference between the exhaust gas temperature of the general gas turbine and the main steam temperature of the gas turbine is ensured to be 20-35 ℃, so that the thermodynamic conditions of boiler design and operation are met. When the exhaust gas temperature of the gas turbine is increased to 630 ℃, the exhaust gas temperature is optimized and increased simultaneously by matching with the parameters of the waste heat boiler, and the reheat steam temperature of the gas turbine can be increased to above 600 ℃. Thus, the steam turbine reheat steam parameter enhancement scheme is thermodynamically viable, with appropriate component materials generally selected to ensure performance during long term reliable operation of the turbine.
The unit operation mode is optimized, so that the automation level of the unit is greatly improved, manual operation is rarely needed in the whole starting process, once the unit is started after a command operation unit is received, the unit can be fully loaded in a short time, and the stability of the unit is enhanced.
The method has the advantages that the whole set of unit load control is designed and put into, the reasonable distribution of loads borne by the gas turbine and the steam turbine is completed, the monitoring and the control of the main steam pressure of the waste heat boiler are completed, the primary frequency modulation function of the unit is realized, and the method has practical value for realizing the safe and stable operation of the gas turbine and the steam turbine and optimizing the peak regulation capacity of the gas turbine and the steam turbine.
The control strategy of the gas-steam combined cycle unit provided by the invention aims at the control characteristics of a gas turbine, a waste heat boiler, a steam turbine and the like, meets the overall control function requirement of the combined cycle unit, ensures the requirement of the whole combined cycle unit on rapid load lifting and lowering, and meets the requirement of a power grid dispatching department. The control strategy has clear logic, strong controllability and strong universality and practicability.
Preferably, alloy steels with lower creep resistance requirements (e.g., 1% CrMoV, including G17CrMoV 5-10) can only be used at temperatures below 565 ℃ and cannot meet the higher steam temperature requirements. Accordingly, material development and qualification development projects over the past twenty years have focused on 9-11% Cr steel, also known as creep strength enhanced ferritic steel (CSEF) (e.g., ASTM tubing, grades P91, P92). The aim is to further improve the high temperature performance of the series of alloy steels by optimizing the alloy element composition and adding new alloy elements such as niobium (Nb) and nitrogen (N) on the basis of 12% CrMoV. Wherein, the casting material GX12 CrMoVNbN-1 still has good creep resistance performance when the application temperature is raised to 620 ℃ by virtue of tempering refining and 9-11% Cr alloy composition, and the casting material GX12 CrMoVNbN-1 has been applied to important parts such as valves, cylinders and the like for many years.
The closed-loop control of the total power of the combined cycle unit is realized, the power generation power of the whole plant is convenient to uniformly schedule, and a realization platform is provided for primary frequency modulation.
Furthermore, the exhaust-heat boiler is matched with a gas turbine, the exhaust temperature of the gas turbine is up to 630 ℃, and compared with a conventional F-level unit, the exhaust temperature of the gas turbine is greatly improved. In the research and development process of the waste heat boiler, the waste heat boiler is mainly suitable for higher exhaust temperature of the gas turbine through the following two-point design:
The final-stage reheater is arranged on the first-stage heating surface and is positioned on the nearest side of the outlet of the combustion engine, and directly bears the scouring of the high-temperature flue gas at 630 ℃ so that the temperature of the main steam outlet for reheating is as high as 605 ℃ and is about 40 ℃ higher than that of the conventional reheater.
The high-pressure superheater de-superheated water is pumped from the outlet of the high-pressure feed pump by the conventional method, is designed to be pumped from the stage of the high-pressure economizer, and improves the parameters of the high-pressure main steam outlet.
The reasonable distribution of load demands is realized, and the combined cycle effect is utilized to the maximum extent. Not only meets the requirement of the rapidity of lifting load, but also matches with the economic design of the combined cycle unit. Upgrading the final reheater material of the waste heat boiler to adapt to higher outlet steam temperature of the waste heat boiler; the air after the temperature is raised is utilized to operate the gas-steam combined cycle unit, so that the energy reuse rate is improved.
In this embodiment, the final reheater of the waste heat boiler is arranged on the first-stage heating surface, namely, on the side closest to the combustion engine, and the direct-fired combustion engine discharges smoke. Under the partial load working condition, the exhaust temperature of the combustion engine is higher than the rated load working condition, so that the high-temperature reheat steam can be lifted to 605 ℃ (reaching the level of the ultra-supercritical unit). On the turbine side, the combined cycle efficiency is improved finally by upgrading the materials such as an inner cylinder and a rotor of the medium-pressure turbine, a medium-pressure main steam valve, a high-temperature reheat steam pipeline, a valve and the like.
In the system design, the high-temperature reheat steam system (including a turbine bypass system and a corresponding drainage system) and the temperature reduction water system are also improved. The high-temperature reheat steam, the front steam of the medium-pressure bypass valve and the drain pipeline of the high-temperature reheat steam are made of P92 materials, and the inlet section of the medium-pressure bypass valve, the drain system valve of the high-temperature reheat steam pipeline and the like are made of F92 materials; the desuperheating water of the high-pressure interstage and final-stage desuperheating system is extracted from the outlet pipeline of the high-pressure water feeding pump, is regulated to be extracted from the outlet of the high-pressure economizer, and enters the desuperheater pipeline through a desuperheater regulating valve and a desuperheater spray head.
The technical scheme of the invention also has the following beneficial effects:
1. The revolutionary innovation is carried out based on the principle and the characteristics of the combined cycle, so that the wide load efficiency improvement of the combined cycle unit is realized;
2. through estimation, the initial investment is only increased by 250 ten thousand yuan (including the material upgrading cost of an inner cylinder and a rotor of a medium-pressure turbine, a medium-pressure main steam valve, a high-temperature reheat steam pipeline, a valve and the like), but the total output of the combined cycle is slightly increased, the thermal efficiency is improved by 0.16%, the generating income of a unit can be increased, and the fuel cost is reduced. The final annual revenue can be up to 150 ten thousand yuan. The static recovery period is less than 2 years.
3. No additional system is added, which is simpler and more reliable from a control point of view.
4. The application range is wide, working condition efficiency is improved from 50% -100%, and the 75% aging benefit is optimal. According to investigation, the annual average load rate of the combined cycle unit serving as a peak regulation function is about 75%. The scheme of the invention is fit for the actual operation of the current peak shaving power plant.
Although the present disclosure has been described above, the scope of the present disclosure is not limited thereto, and those skilled in the art can make various changes and modifications which fall within the scope of the present disclosure without departing from the spirit and scope of the present disclosure.
Claims (2)
1. The utility model provides a system that wide load operation control of gas steam combined cycle peak shaver set improves effect which characterized in that, the system includes:
The load value acquisition unit is used for acquiring the actual power value and the target load value of the gas-steam combined cycle unit;
A load control unit for controlling the load of the gas turbine according to the deviation between the actual power value and the target load value, so that the actual power value is consistent with the target load value;
the load distribution unit is used for correcting the load proportion of the gas turbine, the waste heat boiler and the steam turbine according to the actual running condition of the gas-steam combined cycle unit;
A load change rate calculation unit for automatically calculating the load change rate of the gas-steam combined cycle unit according to the load change rate upper limit, the load change rate lower limit, the exhaust temperature and the steam turbine cylinder temperature change rate of the gas turbine,
The waste heat boiler final-stage control unit is used for controlling the output temperature of a waste heat boiler final-stage reheater and is matched with the load capacity value of the gas-steam combined cycle unit;
wherein the load control unit controls synchronous load rise of the gas turbine and the steam turbine according to the load change rate;
the system further comprises: the sequential control start-stop unit is used for controlling the sequential control start-stop with breakpoint confirmation under the working conditions of cold start, warm start, hot start and normal stop of the steam turbine and controlling the diffusion combustion, the mixed combustion and the load rising rate of the gas turbine under the working conditions of premixed combustion;
The unit load capacity calculation unit is used for calculating each maximum load capacity value which can be born by the gas-steam combined cycle unit under different operation conditions, and limiting the load of the gas-steam combined cycle unit under different operation conditions to the corresponding maximum load capacity value;
the method of controlling the system further comprises the steps of:
Acquiring a real power value and a target load value of the gas-steam combined cycle unit;
Raising the temperature of air entering an air inlet of an air inlet module of the gas-steam combined cycle unit;
According to the deviation between the actual power value and the target load value, controlling the load of the gas turbine to enable the actual power value to be consistent with the target load value;
The final-stage reheater is arranged on the first-stage heating surface and is nearest to the outlet of the combustion engine, so that the final-stage reheater directly bears the scouring of high-temperature flue gas;
Upgrading the final reheat material of the exhaust heat boiler to creep strength reinforced ferritic steel to accommodate higher exhaust heat boiler outlet steam temperatures;
The high-pressure superheater de-superheated water is extracted from the outlet of the high-pressure feed pump and is extracted from the interstage of the high-pressure economizer, so that the parameters of the high-pressure main steam outlet are improved;
Operating the gas-steam combined cycle unit by utilizing the air with the temperature increased;
the method further comprises the steps of:
according to the actual running condition of the gas-steam combined cycle unit, controlling the load proportion of the gas turbine, the waste heat boiler and the steam turbine;
automatically calculating the load change rate of the gas-steam combined cycle unit according to the load change rate upper limit, the load change rate lower limit, the exhaust temperature and the steam turbine cylinder temperature change rate of the gas turbine, and controlling synchronous load rising of the gas turbine and the steam turbine according to the load change rate;
the method further comprises the steps of:
Controlling cold start, warm start, hot start and sequential control start and stop with breakpoint confirmation under normal stop working conditions of the steam turbine, and controlling diffusion combustion, mixed combustion and load rising rate of the gas turbine under premixed combustion working conditions;
The method further comprises the steps of: calculating the maximum load capacity value of the gas-steam combined cycle unit under different operation conditions;
the method further comprises the steps of: and controlling the output temperature of the final-stage reheater of the waste heat boiler to be matched with the load capacity value of the gas-steam combined cycle unit.
2. The system for improving wide load operation control efficiency of a gas and steam combined cycle peak shaver set according to claim 1, wherein the system further comprises: the desuperheater water of the reheater interstage and final-stage desuperheater system is extracted by an outlet pipeline of the medium-pressure water supply pump, and a desuperheater spray head and a desuperheater regulating valve enter a desuperheater pipeline.
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| CN101769180A (en) * | 2009-01-05 | 2010-07-07 | 华北电力科学研究院有限责任公司 | Control method and system thereof for biaxial gas-steam combined cycle unit |
| CN206001429U (en) * | 2016-08-29 | 2017-03-08 | 哈尔滨锅炉厂有限责任公司 | A kind of double reheat π type boiler |
| CN113958413A (en) * | 2021-11-15 | 2022-01-21 | 西安热工研究院有限公司 | Gas-steam combined cycle intake fuel coupling heating system and method |
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| CN106989611B (en) * | 2017-05-18 | 2023-11-24 | 中冶华天南京工程技术有限公司 | Coke oven gas and dry quenching waste heat comprehensive power generation system |
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| CN101769180A (en) * | 2009-01-05 | 2010-07-07 | 华北电力科学研究院有限责任公司 | Control method and system thereof for biaxial gas-steam combined cycle unit |
| CN206001429U (en) * | 2016-08-29 | 2017-03-08 | 哈尔滨锅炉厂有限责任公司 | A kind of double reheat π type boiler |
| CN113958413A (en) * | 2021-11-15 | 2022-01-21 | 西安热工研究院有限公司 | Gas-steam combined cycle intake fuel coupling heating system and method |
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