Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
  • F01K3/00—Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein
  • F01K3/18—Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein having heaters
  • F01K3/20—Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein having heaters with heating by combustion gases of main boiler
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
  • F01K23/00—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
  • F01K23/02—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled
  • F01K23/06—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle
  • F01K23/10—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle with exhaust fluid of one cycle heating the fluid in another cycle
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
  • F01K3/00—Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein
  • F01K3/18—Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein having heaters
  • F01K3/26—Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein having heaters with heating by steam
  • F01K3/262—Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein having heaters with heating by steam by means of heat exchangers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F22—STEAM GENERATION
  • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
  • F22B1/00—Methods of steam generation characterised by form of heating method
  • F22B1/02—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers
  • F22B1/021—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers with heating tubes in which flows a non-specified heating fluid
• • 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]

Definitions

• the invention relates to a method for operating a power plant, in which a guided in a closed steam cycle working medium during the passage of three immediately downstream in the flow direction in a waste heat boiler units preheater, evaporator and superheater at constant pressure over a heating gas heat is supplied to the first liquid
• Heat storage is initiated, removed from the heat time lag and fed to the working medium.
• the invention relates to a power plant, which can be operated by the method according to the invention.
• Power grid would come.
• the demand for electricity is not constant over time. For example, during the day it is about three times as large as at night. It is also higher on weekdays than on weekends and is higher in winter than in summer. By switching on and off or the up and
• Frequency fluctuations or even leads to a failure of the power grid it is supplied to power storage such as pumped and compressed air storage power plants, which can be controlled very quickly and within minutes between power consumption and
• Gu D power plants Through an increased use of "simple" constructed gas and steam power plants (hereinafter referred to as Gu D power plants), the problem described can be mitigated because they have a relatively high electrical efficiency of more than 50% and relatively short start times and a high one
• Gas turbine be used in the waste heat boiler of a downstream steam generator for generating superheated steam, which is expanded in a single-stage steam turbine work, are able to compensate for short-term fluctuations in the public grid.
• CCGTs of the most modern design are designed with a multi-stage steam turbine and have reheaters, which are also located in the waste heat boiler, and in which the relaxed in a pressure stage of the turbine steam is reheated prior to its introduction into the following pressure stage.
• This makes it possible to approximate the cooling curve of the gas turbine exhaust gases and the heating curve of water or steam and thus to minimize exergy losses.
• power plants achieve electrical efficiencies of more than 60%, but because of their highly complex structure, they have only a very low load flexibility and are therefore less suitable to compensate for rapid network fluctuations.
• the patent application DE10260992 proposes a heat accumulator arranged parallel to the steam generator into which a subset of the hot gas turbine exhaust gas can be introduced in order to deliver heat to a storage mass.
• Stored heat is removed from the heat storage tank with a time delay via a gas flow and used for steam generation, including the gas stream heated in the heat steamer is added to the gas turbine exhaust gas before entering the waste heat boiler of the steam generator.
• the patent application provides, during the heat storage to operate the gas turbine with a higher and / or the steam turbine with a lower than the rated power.
• the gas turbine works with a lower and / or the steam turbine with a higher than the rated power when heat is removed from the heat storage. Inevitably occur in this mode losses, which reduce the electrical efficiency of the Gu D power plant sensitive.
• the object of the invention is therefore to provide a method of the generic type and a power plant to be operated according to this method by which the disadvantages of the prior art are overcome.
• This object is achieved procedurally according to the invention that the majority of the heat removed from the heat storage for
• the predominant part of the heat removed from the heat accumulator is to be understood as a fraction which is greater than 50% and preferably greater than 70% of the total heat removed from the heat accumulator. Particularly preferred is the entire heat removed from the heat storage
• the steam turbine of a generic power plant can be operated either in the normal, in the on or in the Aus Grandemodus.
• the amount of the working medium supplied during normal mode of the steam turbine and hereinafter referred to as the normal amount is - apart from the characteristics of the system - determined solely by the thermodynamic parameters of the fuel gas.
• the amount of the steam generation process heat is removed and introduced into the heat accumulator, the amount of the steam
• the method according to the invention makes it possible to reduce the exergy losses which inevitably occur during heat transfer to the working medium in comparison to the prior art and thus to compensate for the losses occurring during the temporary storage of the heat. This will be explained in more detail with reference to the T-Q diagram of Figure 1, in which the Anürmkurve the working medium and the cooling curves of the fuel gas in normal and Aus shallmodus are shown schematically.
• the heating curve 1 of the working medium in the normal mode is composed of the three sub-curves 1A, 1 B and 1C.
• the liquid working medium is heated in the preheater according to the curve 1 A up to its vaporization temperature T v and evaporated in the evaporator at a constant temperature, as shown by the curve 1B.
• the steam formed is finally overheated by further energy supply according to curve 1C to the live steam temperature T F.
• the heating gas is cooled in accordance with the curve 2, which extends between the inlet temperature in the waste heat boiler T and the outlet temperature T of substantially constant gradient.
• the curve 5 shows the cooling of the fuel gas in the Ausssenmodus again, in which the amount of the working medium is increased compared to the normal amount.
• the heating gas therefore transfers both in the superheater, as well as in the preheater larger amounts of heat and is cooled more than in the normal mode, which by the greater slope of the cooling curve 5 with respect to the curve 2 and the flatter course of the partial curves 3C and 3A of the heating curve 3 with respect to the curves 1C and 1A is expressed. Since a portion of the working fluid is vaporized by heat removed from the heat accumulator, only a portion of the working fluid flows through the evaporator, which is smaller than the amount to be evaporated in the normal mode of the working medium.
• the amount of heat to be transferred in the evaporator is correspondingly lower, which leads to a shortening of the evaporation curve 3B in comparison to the corresponding curve 1 B of the normal mode.
• the amount of working medium passed through the evaporator is chosen so that a temperature difference to the heating curve 3B required for effective heat transfer is always maintained. Cooling curve 5 and heating curve 3 therefore run in the Ausatoriummodus with a shorter distance and close a much smaller area than the
• a partial amount can be diverted from the heating gas flow, which is subsequently removed heat for introduction into the heat accumulator.
• the part of the heating gas that has cooled down can then be discharged from the process.
• it is preferably introduced into the waste heat boiler, specifically at a point at which its temperature corresponds to the temperature of the hot gas flowing at the point of introduction or deviates from it by not more than 100 ° C.
• the cooled partial amount of the heating gas upstream of the evaporator and downstream of the superheater is introduced into the waste heat boiler.
• a further preferred variant of the method provides that heat is removed from the heating gas in the region of the superheater via a heat exchanger arranged in the waste heat boiler and through which a heat transfer medium flows.
• Heat transfer medium which may be, for example, a molten salt, and absorbs heat from the Schugasstrom at the passage of the heat exchanger, is subsequently introduced into a heat storage and / or heat by heat exchange to a heat storage, removed from the heat with a time delay and is supplied to the steam generating process.
• Another preferred method variant provides for a subset of the
• the gas phase of the cooled portion of the live steam is usefully returned to the steam generation process upstream of the superheater and downstream of the evaporator recycled, while the liquid phase is preferably introduced downstream of the preheater and upstream of the evaporator.
• FIG. 2 is to be explained in more detail, in which the Anürmkurve the working medium and the cooling curves of the fuel gas in normal and Ein agendamodus are shown schematically.
• the heat to be stored is in this case a partial flow of the
• the heating curve 1, which is divided into the three partial curves 1A, 1 B and 1 C, and the cooling curve 2 of the heating gas in the normal mode run as the corresponding curves in the TQ diagram of Figure 1.
• the curve 4 indicates the cooling of the heating gas in the waste heat boiler during the storage mode, where the amount of working fluid is less than the normal amount. Upstream of the waste heat boiler, a subset of the hot gas is diverted, the size of which is adjusted so that the remaining amount of hot gas is cooled at the superheater more than in the normal mode, which is expressed by the steep compared to the cooling curve 2 part curve 4C. Downstream of the superheater will be outside the
• Waste heat boiler cooled subset of the fuel gas introduced into the waste heat boiler and admixed to the superheater cooled heating gas flow the two Schugasteilströme at the point of introduction have substantially the same temperatures.
• the partial curves 4A and 4B of the cooling curve 4 are flatter than the Abkühlkurve 2. Since the cooling curve 4 has a much smaller distance to heating curve 1 and with this a clear Including smaller area, the exergy losses in the waste heat boiler are also lower in the storage mode than in the normal mode. In the storage mode, the fuel gas leaves the waste heat boiler at a much higher temperature than in the
• Aus modifies the cooled fuel gas in a subsequent process in which, for example, heat is provided for feeding into a district heating network.
• any power plant in which superheated steam is generated in a waste heat boiler in order to operate in accordance with the method according to the invention becomes.
• the method is used to operate a combined cycle power plant, wherein the hot exhaust gas of one or more gas turbines serves as heating gas.
• an oxidizing agent and / or a fuel are added to the hot exhaust gas in order to increase the temperature and the energy content of the heating gas.
• the inventive method can significantly increase the flexibility, in particular, of "simple" combined cycle power plants with a single-stage steam turbine, which are thus particularly suitable for use in compensating for grid fluctuations in the save mode, increased in times
• the power plant is operated in all three modes with the same amount of fuel gas, so that only the amount of im
• Steam generator having a closed steam cycle with a preheater, an evaporator and a superheater and a waste heat boiler, in which the preheater, the evaporator and the superheater are arranged, through which a feasible through the waste heat boiler heating heat can be withdrawn, as well as a Exchange device, through which the steam generator heat withdrawn and can be introduced into a heat accumulator, from the heat with a time delay removed and the steam generator can be fed.
• the object is achieved device-side according to the invention that the exchange device is connected to the steam generator so that
• Heat accumulator removed heat evaporated and the steam generated while bypassing the evaporator can be introduced into the superheater.
• the exchange device is connected to the steam generator such that a subset of the fuel gas can be withdrawn heat before its introduction into the waste heat boiler and introduced into the heat storage.
• the exchange device with the waste heat boiler is connected so that the cooled in the heat transfer to the heat storage subset of
• Hot gas downstream of the superheater and upstream of the evaporator can be introduced into the waste heat boiler and returned to the heating gas stream.
• a heat exchanger is arranged through which a heat transfer medium can be performed to extract heat from the heating gas by indirect heat exchange and initiate into the heat storage.
• a further embodiment of the power plant according to the invention provides that the
• Exchange device is connected to the outlet side of the superheater, so that a subset of the emerging from the superheater working medium heat can be withdrawn and introduced into the heat accumulator.
• the exchange device is connected in this case with the steam generator so that the cooled in the heat transfer to the heat storage subset of
• Working medium at a downstream of the evaporator and located upstream of the superheater point can be returned to the steam cycle.
• a power plant according to the invention can have as heat storage device, which is known from the prior art for the storage of heat.
• it comprises a molten salt reservoir containing molten salt as the heat storage medium.
• a preferred embodiment of the invention provides that the power plant is a combined cycle power plant which has one or more gas turbines connected to the waste heat boiler such that the hot exhaust gas of the turbine or turbines can be introduced into the waste heat boiler as heating gas ,
• a further preferred embodiment of the invention provides that the steam turbine is designed as a single-stage steam turbine.
• FIG. 3 shows a power plant according to the invention which is operated in the withdrawal mode.
• FIG. 4 shows a power plant according to the invention which is operated in the storage mode.
• a working medium which is preferably water.
• a working medium which is preferably water.
• Waste heat boiler A are arranged, passed.
• a heating gas 3 which is preferably the exhaust gas of one or more gas turbines, out, which emits a portion of its thermal energy to the working fluid.
• the superheated, generated in the waste heat boiler A steam 2 is working expanded in the connected to the generator G steam turbine W, whereby electric power 4 is produced.
• the condenser E1 the expanded working medium 5 is liquefied and introduced into the tank T, from which it is removed by means of the pump P and fed back to the preheater B.
• the Aus Grande modus the full amount of the heating gas 3 is passed through the entire waste heat boiler A.
• a subset 6 of the working medium is diverted from the steam cycle D and passed to the evaporation via the heat exchanger E2, which is connected to the heat accumulator S.
• the energy required for the evaporation of the subset 6 is in this case taken from the heat storage S, while the remaining amount of the working medium in the evaporator V is evaporated by heat exchange with the heating gas 3.
• the steam 7 formed in the heat exchanger E2 is subsequently returned downstream of the evaporator V and upstream of the superheater U back into the steam cycle D, so that the entire amount of the working medium converted to superheated steam 2 and can be relaxed in the steam turbine W work.
• Waste heat boiler A initiated and cooled with the overheater U
• Heating gas stream 10 combined to 9 Bank of Water. It makes sense to have the two Schugasströme 9 and 10 at the admixing Z equal temperatures.
• the combined heating gas stream 1 1 is further cooled at the evaporator V and the preheater B, before he leaves the waste heat boiler A as the exhaust gas 12 and is released into the atmosphere.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Sustainable Development (AREA)
• Sustainable Energy (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Engine Equipment That Uses Special Cycles (AREA)

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Cited By (4)

Citations (6)

• 2013
  • 2013-06-11 WO PCT/EP2013/001711 patent/WO2013185909A1/fr not_active Ceased

Patent Citations (6)

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