A device system and method for regenerative extraction steam energy storage to assist frequency regulation and peak shaving power generation

Abstract

The present invention provides a device system and method for regenerative extraction steam energy storage assisted frequency modulation and peak shaving power generation. By coupling a heat storage material charging device system to the regenerative extraction steam device system, the sensible heat of the extraction steam is absorbed and stored. When the unit performs frequency modulation and increases the load, the extraction steam frequency modulation valve of the heat storage system for storing heat can quickly participate in the load increase frequency modulation response of the unit, which is more direct and faster in response speed than the feed water frequency modulation scheme. At the same time, the thermal inertia of the heat storage material charging device system is used to maintain the stability of the feed water temperature, improving the operation safety of the regenerative system and the boiler. The device system of the present invention stores the excess heat during the normal operation of the unit and releases it concentratedly during the peak period, which can support the unit to obtain additional peak shaving operation capacity and is suitable for large-scale popularization and application in thermal power units.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal power generation, and in particular to a device system and method for regenerative extraction steam energy storage assisted frequency modulation and peak power generation. Background Art

[0002] Currently, advanced ultra-supercritical coal-fired thermal power units are constantly pursuing higher thermoelectric conversion efficiency, and mostly operate in a full-arc admission and full sliding pressure mode. In this mode, the main steam valve of the steam turbine is fully open. Although the throttling loss of the working medium is reduced, the function of actively participating in the grid system load increase frequency modulation by further opening the main steam valve is lost. The load of the turbogenerator is adjusted following the load of the boiler. Due to the large thermal inertia of the coal-fired boiler, the frequency modulation response ability of the actual grid-connected large units in sliding pressure regulation is seriously insufficient, increasing the operating burden of the power plant and bringing technical risks to the grid to maintain power and frequency stability.

[0003] In order to improve the frequency modulation ability of large thermal power units, a lithium iron phosphate electrochemical energy storage system can be configured, and the frequency modulation performance of the unit can be significantly improved. However, due to its high cost, short cycle service life, and a series of environmental protection derivative problems in the recycling of waste batteries, and there is also a certain risk of explosion and combustion for lithium batteries, and its inherent safety has not been fundamentally solved. How to obtain a more safe, effective and economical energy storage frequency modulation solution is an urgent problem for those skilled in the art.

[0004] From the perspective of the thermal system, in practice, frequency modulation technologies such as feedwater frequency modulation and condensate water frequency modulation for rapid load increase of the unit have emerged. These frequency modulation technologies indirectly affect the extraction steam volume by using the water side parameters of the regenerative system, and indirectly realize the intervention and regulation of the unit load, with certain effects. However, the system does not receive the dynamic support of an additional energy storage device, and the frequent fluctuation of the feedwater temperature will affect the operation regulation and safety reliability of the boiler, or damage the service life of the equipment in the regenerative system. Large thermal power units designed in a pure condensing mode mostly implement heat supply transformation during the operation period for energy conservation and consumption reduction. In the heat extraction steam condition, the peak power generation ability is prone to be weak, and it is even difficult to reach the rated power generation output, resulting in a certain loss of reliable standby capacity for the grid. How to use thermal energy storage means to support the peak operation function of the retrofitted cogeneration units is also an important direction for the evolution and development of thermal power in the future new power system.

[0005] CN112855293A discloses an industrial steam supply combined heat and power peak shaving and frequency modulation system with integrated heat storage and its operation method. The system consists of a coal-fired power generation system, a steam supply system, and a heat storage material heat storage system. The coal-fired power generation system includes a boiler, a steam turbine, a condenser, a condensate pump, high and low pressure heaters, a deaerator, and a feed water pump. The steam supply system includes a cold and hot reheat extraction steam regulating valve, an industrial steam supply header, a steam generator, a water tank feed pump, and a steam supply make-up water tank. The heat storage material heat storage system includes a heating selection valve, a heat storage material thermal heater, a heat storage material electric heater, a heat storage material regulating valve, high and low temperature heat storage material tanks, and high and low temperature heat storage material pumps. The heating steam includes cold and hot reheat extraction steam and the steam generated in the steam generator, and the three cooperate with each other to meet the requirements of the steam heat network. By adjusting the opening of the cold and hot reheat extraction steam regulating valves and the speed of the water tank feed pump, the heat storage of the heat storage material is used to assist the coal-fired power generation system to quickly increase and decrease the load, improving the operating flexibility of the unit.

[0006] CN114216108A discloses a heat storage peak shaving system for hybrid heating heat storage materials, including a superheater, a reheater, a main steam control valve, a high-pressure cylinder, a reheated steam control valve, a medium-pressure cylinder, a low-pressure steam control valve, a low-pressure cylinder, a generator, an electrical switch, a regenerative heater, a deaerator, a feed water pump, a condenser, a condensate pump, a steam-pressure water heat exchanger, a pressure water pump, an atmospheric water tank, a pressure water tank, a high-temperature heat storage material pump, a steam-heat storage material heat exchanger, an electric heater, a low-temperature heat storage material pump, a low-temperature heat storage material storage tank, a high-temperature heat storage material storage tank, a heat storage material-pressure water heat exchanger, a wind power generation set, and valves. The excess heat and electricity during the unit's load reduction for peak shaving, as well as the excess electricity from wind power generation and photovoltaic power generation, are stored in the high-temperature heat storage materials; during the unit's load increase process, the high-temperature heat storage materials are used to heat the pressure water to generate high-temperature pressure water or high-temperature high-pressure steam, which enters the original unit's thermal system to increase the unit's power generation capacity; in this way, the flexible deep peak shaving of thermal power plants is achieved with a relatively high thermal efficiency.

[0007] CN114151777A discloses a heat storage material heat storage peak shaving and alternative start-up boiler system, including a traditional thermal power generation system and a heat storage material heat storage peak shaving and alternative start-up boiler system. When the unit operation meets the grid load requirements, the traditional thermal power generation system operates normally, and the heat storage material heat storage peak shaving and alternative start-up boiler system exits the operation; when the load is reduced, the heat storage material heat storage peak shaving operation mode is turned on, and the excess power is converted into the heat energy of the heat storage material for storage; during the load increase process, the heat storage material heat storage peak shaving operation mode is turned on, and the heat energy stored in the heat storage material heats the demineralized water to generate superheated steam and enters the low-pressure cylinder of the steam turbine; when the unit is started for the first time after shutdown, the alternative start-up boiler operation mode is turned on, and the heat storage material is used to heat the demineralized water to generate steam. The heat storage technology of the heat storage material can not only perform peak shaving on thermal power generation but also play the role of replacing the start-up boiler, reducing the impact of the need for long-term maintenance of the original start-up boiler and non-compliance with environmental protection parameters, and improving the flexibility and safety of the operation of coal-fired units.

[0008] However, the peak operation ability of the above device system still needs to be further improved.

[0009] Therefore, it is of great significance to develop a device system and method for using regenerative extraction steam energy storage to assist thermal power units in frequency modulation and peak power generation. Summary of the Invention

[0010] In view of the problems existing in the prior art, the present invention provides a device system and method for regenerative extraction steam energy storage-assisted frequency modulation and peak power generation, which couples a heat storage material charging device system to the regenerative extraction steam device system, absorbs the sensible heat of the extraction steam and stores it, realizes extraction steam energy storage, assists the unit in frequency modulation and improves the peak power generation operation ability of the unit.

[0011] To achieve this purpose, the present invention adopts the following technical solutions:

[0012] In the first aspect, the present invention provides a device system for regenerative extraction steam energy storage-assisted frequency modulation and peak power generation. The device system includes a boiler, a high-pressure cylinder of a steam turbine, an intermediate-pressure cylinder of a steam turbine, a low-pressure cylinder of a steam turbine, a condenser, a low-pressure heating device module, a deaerator, and a high-pressure heating device module that are connected in a cycle;

[0013] The high-pressure cylinder of the steam turbine is connected to the heat storage material charging device through a first extraction steam pipeline, or the intermediate-pressure cylinder of the steam turbine is connected to the heat storage material charging device through a second extraction steam pipeline;

[0014] The heat storage material charging device is connected in a cycle with a first heat storage material storage device, a heat storage material heat release device, and a second heat storage material storage device.

[0015] In the device system for regenerative extraction steam energy storage for auxiliary frequency modulation and peak shaving power generation according to the present invention, a regenerative extraction steam device system is composed of a boiler, a high-pressure cylinder of a steam turbine, an intermediate-pressure cylinder of the steam turbine, a low-pressure cylinder of the steam turbine, a condenser, a low-pressure heating device module, a deaerator, and a high-pressure heating device module that are connected in a cycle. A heat storage material charging device is connected in a cycle with a first heat storage material storage device, a heat storage material heat release device, and a second heat storage material storage device to form a heat storage material charging device system. The high-temperature gas sensible heat of the high-pressure cylinder of the steam turbine or the intermediate-pressure cylinder of the steam turbine is stored between the two through a first extraction steam pipeline or a second extraction steam pipeline. The stored heat can participate in the rapid response of the unit load increase for frequency modulation, which is more direct and has a faster response speed than the feed water frequency modulation scheme. Moreover, by utilizing the thermal inertia of the heat storage material, the stability of the main feed water temperature during frequency modulation operation is maintained, and the operation safety of the regenerative extraction steam device system and the boiler is improved. When the device system is operating normally, the excess heat is stored in the first heat storage material storage device, and during the peak period, the heat is released through the heat storage material heat release device, and the original extraction steam returns to the unit to continue doing work, increasing the peak operation capacity of the unit.

[0016] The heat storage material described in the present invention can be molten salt or other phase change heat storage materials, which can support relatively independent time-sharing adjustment operations for the heat charging and heat release processes.

[0017] Preferably, the device system further includes an ultra-high-pressure cylinder of the steam turbine.

[0018] The ultra-high-pressure cylinder of the steam turbine described in the present invention is applicable to a double reheat unit.

[0019] The ultra-high-pressure cylinder of the steam turbine, the high-pressure cylinder of the steam turbine, the intermediate-pressure cylinder of the steam turbine, and the low-pressure cylinder of the steam turbine described in the present invention are well-known device names in the art.

[0020] The low-pressure heating device module described in the present invention includes a plurality of low-pressure heaters arranged in series in sequence; the high-pressure heating device module includes a plurality of high-pressure heaters arranged in series in sequence.

[0021] Preferably, the ultra-high-pressure cylinder of the steam turbine is respectively connected to the boiler and the high-pressure cylinder of the steam turbine.

[0022] Preferably, the ultra-high-pressure cylinder of the steam turbine is connected to the high-pressure heating device module.

[0023] Preferably, the device system further includes a steam cooling device.

[0024] Preferably, the steam cooling device is arranged between the high-pressure heating device module and the boiler.

[0025] Preferably, the steam cooling device is connected to the intermediate-pressure cylinder of the steam turbine.

[0026] Preferably, the heat storage material charging device is connected to the high-pressure heating device module.

[0027] The heat storage material charging device of the present invention can be connected to any one of the high-pressure heaters in the high-pressure heating device module to heat it.

[0028] Preferably, the heat storage material heat release device is respectively connected to the boiler and the high-pressure heating device module.

[0029] An exhaust pipeline can also be provided in the heat storage material heat release device of the present invention to heat the working medium at other positions.

[0030] Preferably, the number of low-pressure cylinders of the steam turbine is at least 1, for example, it can be 1, 2, or 3.

[0031] Preferably, the number of low-pressure heaters in the low-pressure heating device module is 4 or 5.

[0032] Preferably, the number of high-pressure heaters in the high-pressure heating device module is 3 or 4.

[0033] Preferably, the number of heat storage material heat release devices is at least 1, for example, it can be 1, 2, 3, or 4.

[0034] When the number of heat storage material heat release devices of the present invention is more than 2, each heat storage material heat release device is connected in parallel or in series.

[0035] Preferably, the high-pressure cylinder of the steam turbine is respectively connected to the boiler and the high-pressure heating device module.

[0036] Preferably, the intermediate-pressure cylinder of the steam turbine is respectively connected to the deaerator and the low-pressure heating device module.

[0037] Preferably, the low-pressure cylinder of the steam turbine is connected to the low-pressure heating device module.

[0038] Preferably, a condensate water conveying device is provided between the condenser and the low-pressure heating device module.

[0039] Preferably, a feed water conveying device is provided between the deaerator and the high-pressure heating device module.

[0040] Preferably, a first extraction frequency modulation valve is provided on the first extraction pipeline.

[0041] Preferably, a second extraction frequency modulation valve is provided on the second extraction pipeline.

[0042] The first extraction frequency modulation valve and the second extraction frequency modulation valve of the present invention change the extraction operation mode of the regenerative extraction device system to adjustable extraction, and utilize extraction energy storage to directly participate in the unit frequency modulation. When the unit needs to increase load for frequency modulation, the regenerative extraction regulating valve can be quickly throttled, enabling the extraction steam to return to the steam turbine for work and directly participating in the unit's load increase frequency modulation, which is more direct and has a faster response speed than the feed water frequency modulation scheme.

[0043] Preferably, a first heat storage material conveying device is arranged between the first heat storage material storage device and the heat storage material heat release device.

[0044] Preferably, a second heat storage material conveying device is arranged between the second heat storage material storage device and the heat storage material heat charging device.

[0045] The first heat storage material conveying device and the second heat storage material conveying device of the present invention include variable frequency conveying pumps. When ordinary conveying pumps are used, regulating valves also need to be arranged.

[0046] Preferably, a bypass feed water pipeline is arranged between the heat storage material heat release device and the high-pressure heating device module.

[0047] In the device system of the present invention, the layout form of the feed water bypass pipeline is flexible and can be led out and returned from various positions before and after each stage of high-pressure heaters of the high-pressure heating device module.

[0048] Preferably, a bypass feed water regulating valve is arranged on the bypass feed water pipeline.

[0049] Preferably, the device system further includes a power generation device.

[0050] Preferably, the power generation device is connected to the low-pressure cylinder of the steam turbine.

[0051] In a second aspect, the present invention also provides a method for regenerative extraction energy storage assisted frequency modulation and peak shaving power generation. The method is carried out by using the device system for regenerative extraction energy storage assisted frequency modulation and peak shaving power generation described in the first aspect, and the method includes a frequency modulation operation method and a peak shaving operation method.

[0052] Preferably, the frequency modulation operation method includes:

[0053] After the grid frequency drops to a first value and triggers the unit load increase command, the control system adjusts to reduce the opening of the first extraction frequency modulation valve, and the regenerative extraction returns to the high-pressure cylinder of the steam turbine for work, or reduces the opening of the second extraction frequency modulation valve, and the regenerative extraction returns to the intermediate-pressure cylinder of the steam turbine for work; at the same time, the flow rate of the first heat storage material conveying device is increased to maintain the stability of the feed water temperature of the boiler.

[0054] During the frequency modulation operation of the present invention, the regenerative extraction steam is returned to the high-pressure cylinder of the steam turbine to do work or returned to the intermediate-pressure cylinder of the steam turbine to do work, which can short-term increase the power generation capacity of the unit by about 2-5% of the rated power. When the heat storage material charging device loses the heat source for a short time, the temperature of the heat storage material flowing to the first heat storage material storage device slightly decreases. However, due to the large heat storage capacity of the first heat storage material storage device, its macroscopic temperature does not change significantly.

[0055] Preferably, after the frequency modulation operation ends, the first extraction steam frequency modulation valve or the second extraction steam frequency modulation valve is fully opened, and the charging effect of the extraction steam on the heat storage material charging device is restored.

[0056] Preferably, the peak load operation method includes:

[0057] During the peak load operation period, the first extraction steam frequency modulation valve and the high-pressure heater supplied by the extraction steam are shut down, so that the extraction steam does work in the high-pressure cylinder of the steam turbine, or the second extraction steam frequency modulation valve and the high-pressure heater supplied by the extraction steam are shut down, so that the extraction steam does work in the intermediate-pressure cylinder of the steam turbine to support the peak load operation of the unit; increase the flow rate of the bypass feed water regulating valve and synchronously increase the flow rate of the first heat storage material conveying device to increase the peak load operation ability of the unit.

[0058] As a preferred technical solution of the present invention, the method includes a frequency modulation operation method and a peak load operation method; the frequency modulation operation method includes:

[0059] When the grid frequency drops to the first value of 49.967 Hz and triggers the unit load increase command, the control system adjusts and reduces the opening of the first extraction steam frequency modulation valve, and the regenerative extraction steam returns to the high-pressure cylinder of the steam turbine to do work, or reduces the opening of the second extraction steam frequency modulation valve, and the regenerative extraction steam returns to the intermediate-pressure cylinder of the steam turbine to do work; at the same time, increase the flow rate of the first heat storage material conveying device to maintain the stability of the feed water temperature of the boiler;

[0060] After the frequency modulation operation ends, the first extraction steam frequency modulation valve or the second extraction steam frequency modulation valve is fully opened, and the charging effect of the extraction steam on the heat storage material charging device is restored;

[0061] The peak load operation method includes: during the peak load operation period, the first extraction steam frequency modulation valve and the high-pressure heater supplied by the extraction steam are shut down, so that the extraction steam does work in the high-pressure cylinder of the steam turbine, or the second extraction steam frequency modulation valve and the high-pressure heater supplied by the extraction steam are shut down, so that the extraction steam does work in the intermediate-pressure cylinder of the steam turbine to support the peak load operation of the unit; increase the flow rate of the bypass feed water regulating valve and synchronously increase the flow rate of the first heat storage material conveying device to increase the peak load operation ability of the unit.

[0062] Compared with the prior art, the present invention has at least the following beneficial effects:

[0063] (1) Without affecting the efficiency of the thermal system, the device system for regenerative extraction steam energy storage for auxiliary frequency regulation and peak shaving power generation provided by the present invention stores energy through regenerative extraction steam, enabling the thermal power unit to obtain a more direct and rapid means of frequency regulation and load increase, and the load increase value reaches 2-5% of the rated output of the steam turbine.

[0064] (2) The device system for regenerative extraction steam energy storage for auxiliary frequency regulation and peak shaving power generation provided by the present invention can store the sensible heat energy of the extraction steam during normal operation in the heat storage material and release it concentratedly during the peak period, enabling the unit to obtain additional peak operation capacity.

[0065] (3) The method for regenerative extraction steam energy storage for auxiliary frequency regulation and peak shaving power generation provided by the present invention is buffered by a safe and reliable heat storage material charging device system, avoiding the risk of life damage of equipment components caused by frequent temperature fluctuations during conventional feedwater frequency regulation, and is beneficial for the power plant to reduce the risk of unplanned shutdown and maintenance costs. Description of the Drawings

[0066] Figure 1 is a schematic structural diagram of the device system for regenerative extraction steam energy storage for auxiliary frequency regulation and peak shaving power generation provided in Embodiment 1.

[0067] Figure 2 is a schematic structural diagram of the device system for regenerative extraction steam energy storage for auxiliary frequency regulation and peak shaving power generation provided in Embodiment 2.

[0068] Figure 3 is a schematic structural diagram of the device system for regenerative extraction steam energy storage for auxiliary frequency regulation and peak shaving power generation provided in Embodiment 3.

[0069] Figure 4 is a schematic structural diagram of the device system for regenerative extraction steam energy storage for auxiliary frequency regulation and peak shaving power generation provided in Embodiment 4.

[0070] Figure 5 is a schematic structural diagram of the device system for regenerative extraction steam energy storage for auxiliary frequency regulation and peak shaving power generation provided in Embodiment 5.

[0071] In the figure: 10 - boiler; 11 - ultra-high pressure cylinder of steam turbine; 12 - high pressure cylinder of steam turbine; 13 - intermediate pressure cylinder of steam turbine; 14 - first low pressure cylinder of steam turbine; 15 - second low pressure cylinder of steam turbine; 16 - generator; 17 - condenser;

[0072] 20 - first extraction frequency regulation valve; 21 - molten salt heater; 22 - second extraction frequency regulation valve;

[0073] 30 - second molten salt tank; 31 - second molten salt pump; 32 - second molten salt regulating valve;

[0074] 40 - First molten salt tank; 41 - First molten salt pump; 42 - First molten salt regulating valve; 43 - First molten salt heat releaser; 44 - Second molten salt heat releaser;

[0075] 50 - Steam cooler; 51 - First high - pressure heater; 52 - Second high - pressure heater; 53 - Third high - pressure heater; 54 - Fourth high - pressure heater; 55 - Deaerator; 56 - First low - pressure heater; 57 - Second low - pressure heater; 58 - Third low - pressure heater; 59 - Fourth low - pressure heater;

[0076] 60 - Fifth low - pressure heater; 61 - Condensate pump;

[0077] 71 - Feed water pump; 72 - Bypass feed water regulating valve. Detailed implementation mode

[0078] The technical solution of the present invention will be further described below in conjunction with the accompanying drawings and through specific implementation modes.

[0079] The present invention will be described in further detail below. However, the following examples are only simple examples of the present invention and do not represent or limit the scope of the protection of the rights of the present invention. The scope of protection of the present invention is subject to the claims.

[0080] It should be understood that in the description of the present invention, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features.

[0081] It should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "set", "connected", "connected to" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

[0082] Those skilled in the art should understand that the present invention necessarily includes the necessary pipelines, conventional valves and general pump equipment for realizing the complete process. However, the above contents do not belong to the main inventive points of the present invention. Those skilled in the art can add and arrange them by themselves based on the process flow and equipment structure selection, and the present invention has no special requirements and specific limitations on this.

[0083] Example 1

[0084] This embodiment provides a device system for regenerative extraction steam energy storage assisted frequency modulation and peak shaving power generation, and its structural schematic diagram is as shown in Figure 1 shown.

[0085] The device system is based on the thermal system of a secondary reheat unit, and includes a boiler 10, a steam turbine ultra-high pressure cylinder 11 (rated pressure range 30 - 32 MPa), a steam turbine high pressure cylinder 12 (rated pressure range 10 - 13 MPa), a steam turbine intermediate pressure cylinder 13 (rated pressure 3 - 4 MPa), a steam turbine first low pressure cylinder 14 (rated pressure 0.3 - 0.5 MPa), a steam turbine second low pressure cylinder 15 (rated pressure 0.3 - 0.5 MPa), a condenser 17, a low-pressure heating device module, a deaerator 55, and a high-pressure heating device module, which are connected in a cycle.

[0086] A condensate pump 61 is arranged between the condenser 17 and the low-pressure heating device module; the low-pressure heating device module includes a fifth low-pressure heater 60, a fourth low-pressure heater 59, a third low-pressure heater 58, a second low-pressure heater 57, and a first low-pressure heater 56, which are sequentially connected to the condensate pump 61.

[0087] A feed water pump 71 is arranged between the deaerator 55 and the high-pressure heating device module; the high-pressure heating device module includes a fourth high-pressure heater 54, a third high-pressure heater 53, a second high-pressure heater 52, and a first high-pressure heater 51, which are sequentially connected to the feed water pump 71.

[0088] The steam turbine high pressure cylinder 12 is connected to a molten salt charger 21 through a first extraction steam pipeline; the molten salt charger 21 is connected in a cycle with a first molten salt tank 40, a first molten salt releaser 43, and a second molten salt tank 30.

[0089] The device system further includes a steam cooler 50;

[0090] The steam cooler 50 is arranged between the first high-pressure heater 51 in the high-pressure heating device module and the boiler 10; the steam cooler 50 is connected to the steam turbine intermediate pressure cylinder 13.

[0091] The steam cooler 50 is connected to the fourth high-pressure heater 54.

[0092] The molten salt charger 21 is connected to the second high-pressure heater 52 in the high-pressure heating device module; the molten salt releaser 43 is respectively connected to the boiler 10 and the high-pressure heating device module.

[0093] The steam turbine ultra-high pressure cylinder 11 is respectively connected to the boiler 10 and the first high-pressure heater 51 in the high-pressure heating device module;

[0094] The steam turbine high pressure cylinder 12 is respectively connected to the boiler 10 and the third high-pressure heater 53 in the high-pressure heating device module;

[0095] The intermediate-pressure cylinder 13 of the steam turbine is respectively connected to the deaerator 55 and the first low-pressure heater 56 in the low-pressure heating device module;

[0096] The first low-pressure cylinder 14 of the steam turbine is connected to the second low-pressure heater 57; the second low-pressure cylinder 15 of the steam turbine is respectively connected to the fifth low-pressure heater 60, the fourth low-pressure heater 59 and the third low-pressure heater 58.

[0097] A first extraction frequency modulation valve 20 is provided on the first extraction steam pipeline.

[0098] A first molten salt pump 41 and a first molten salt regulating valve 42 are sequentially arranged between the first molten salt tank 40 and the first molten salt heat releaser 43;

[0099] A second molten salt pump 31 and a second molten salt regulating valve 32 are sequentially arranged between the second molten salt tank 30 and the molten salt heater 21.

[0100] A bypass feed water pipeline is provided between the third high-pressure heater 53 and the second high-pressure heater 52 and is connected to the first molten salt heat releaser 43; a bypass feed water regulating valve 72 is provided on the bypass feed water pipeline.

[0101] The device system further includes a generator 16; the generator 16 is connected to the second low-pressure cylinder 15 of the steam turbine.

[0102] This embodiment further provides a method for regenerative extraction steam energy storage assisted frequency modulation and peak power generation. The method includes a frequency modulation operation method and a peak operation method; the frequency modulation operation method includes:

[0103] After the grid frequency drops to the first value of 49.967 Hz and triggers the unit load increase command, the control system adjusts and reduces the opening of the first extraction frequency modulation valve 20, and the regenerative extraction steam at a temperature of 540 °C returns to the high-pressure cylinder of the steam turbine to do work; at the same time, the flow rate of the first molten salt pump 41 is increased to maintain the stability of the feed water temperature of the boiler 10;

[0104] After the frequency modulation operation is completed, the first extraction frequency modulation valve 20 is fully opened, and the heat charging effect of the extraction steam on the molten salt heater 21 is restored again;

[0105] The peak operation method includes: during the peak operation period, the first extraction frequency modulation valve 20 and the second high-pressure heater 52 supplied with extraction steam are shut down, so that the extraction steam does work in the high-pressure cylinder 12 of the steam turbine to support the peak operation of the unit load; the flow rate of the bypass feed water regulating valve 72 is increased, and the flow rate of the first molten salt pump 41 is increased synchronously to increase the peak operation ability of the unit.

[0106] Embodiment 2

[0107] This embodiment provides a device system for regenerative extraction steam energy storage assisted frequency modulation and peak shaving power generation, and its structural schematic diagram is as Figure 2 shown.

[0108] The device system is based on the thermal system of a secondary reheat unit. Except that the intermediate pressure cylinder 13 of the steam turbine is connected to the molten salt heater 21 through the second extraction steam pipeline, a second extraction steam frequency modulation valve 22 is provided on the second extraction steam pipeline, the molten salt heater 21 is connected to the fourth high-pressure heater 54 in the high-pressure heating device module, the high-pressure cylinder 12 of the steam turbine is connected to the steam cooler 50, and the steam cooler 50 is connected to the second high-pressure heater 52, the rest are the same as those in Embodiment 1.

[0109] This embodiment also provides a method for regenerative extraction steam energy storage assisted frequency modulation and peak shaving power generation. The method includes a frequency modulation operation method and a peak shaving operation method; except that the control system adjusts and reduces the opening of the second extraction steam frequency modulation valve 22, and the regenerative extraction steam at a temperature of 560 °C returns to the intermediate pressure cylinder 13 of the steam turbine to do work, the rest are the same as those in Embodiment 1;

[0110] Except that the second extraction steam frequency modulation valve 22 and the fourth high-pressure heater 54 supplied with extraction steam are shut down, and the extraction steam does work in the intermediate pressure cylinder 13 of the steam turbine, the rest of the peak shaving operation method are the same as those in Embodiment 1.

[0111] Embodiment 3

[0112] This embodiment provides a device system for regenerative extraction steam energy storage assisted frequency modulation and peak shaving power generation, and its structural schematic diagram is as Figure 3 shown.

[0113] The device system is based on the thermal system of a single reheat unit, and includes a boiler 10, a high-pressure cylinder 12 of a steam turbine (rated pressure range 16 - 28 MPa), an intermediate pressure cylinder 13 of a steam turbine (rated pressure range 2 - 6 MPa), a first low-pressure cylinder 14 of a steam turbine (rated pressure range 0.5 - 1.2 MPa), a second low-pressure cylinder 15 of a steam turbine (rated pressure range 0.5 - 1.2 MPa), a condenser 17, a low-pressure heating device module, a deaerator 55, and a high-pressure heating device module that are connected in a cycle.

[0114] A condensate pump 61 is provided between the condenser 17 and the low-pressure heating device module; the low-pressure heating device module includes a fourth low-pressure heater 59, a third low-pressure heater 58, a second low-pressure heater 57, and a first low-pressure heater 56 that are sequentially connected to the condensate pump 61.

[0115] A feed water pump 71 is provided between the deaerator 55 and the high-pressure heating device module; the high-pressure heating device module includes a third high-pressure heater 53, a second high-pressure heater 52, and a first high-pressure heater 51 that are sequentially connected to the feed water pump 71.

[0116] The molten salt heater 21 is connected to the third high-pressure heater 53 in the high-pressure heating device module; the molten salt cooler 43 is respectively connected to the boiler 10 and the high-pressure heating device module.

[0117] The intermediate-pressure cylinder 13 of the steam turbine is connected to the molten salt heater 21 through a second extraction pipeline; the molten salt heater 21 is connected in a cycle with the first molten salt tank 40, the first molten salt cooler 43, and the second molten salt tank 30.

[0118] The high-pressure cylinder 12 of the steam turbine is respectively connected to the boiler 10 and the third high-pressure heater 51 in the high-pressure heating device module;

[0119] The intermediate-pressure cylinder 13 of the steam turbine is respectively connected to the deaerator 55 and the first low-pressure heater 56 in the low-pressure heating device module;

[0120] The first low-pressure cylinder 14 of the steam turbine is connected to the second low-pressure heater 57; the second low-pressure cylinder 15 of the steam turbine is respectively connected to the fourth low-pressure heater 59 and the third low-pressure heater 58.

[0121] A second extraction frequency modulation valve 22 is provided on the second extraction pipeline.

[0122] A first molten salt pump 41 and a first molten salt regulating valve 42 are sequentially arranged between the first molten salt tank 40 and the first molten salt cooler 43;

[0123] A second molten salt pump 31 and a second molten salt regulating valve 32 are sequentially arranged between the second molten salt tank 30 and the molten salt heater 21.

[0124] A bypass feed water pipeline is provided between the third high-pressure heater 53 and the second high-pressure heater 52 and is connected to the first molten salt cooler 43; a bypass feed water regulating valve 72 is provided on the bypass feed water pipeline.

[0125] The device system further includes a generator 16; the generator 16 is connected to the second low-pressure cylinder 15 of the steam turbine.

[0126] This embodiment further provides a method for auxiliary frequency modulation and peak power generation of regenerative extraction energy storage, the method includes a frequency modulation operation method and a peak operation method; the frequency modulation operation method is the same as that in Embodiment 2;

[0127] The peak operation method includes: during the peak operation period, the second extraction frequency modulation valve 22 and the third high-pressure heater 53 supplied with extraction steam are shut down, so that in addition to the extraction steam doing work in the intermediate-pressure cylinder 13 of the steam turbine, the rest are the same as those in Embodiment 2.

[0128] Embodiment 4

[0129] This embodiment provides a device system for regenerative extraction steam energy storage to assist frequency modulation and peak load power generation, and its structural schematic diagram is as Figure 4 shown.

[0130] Except for adding a second molten salt reheater 44, the second molten salt reheater 44 is arranged in parallel with the first molten salt reheater 43, connecting the high-pressure cylinder 12 of the steam turbine to the second molten salt reheater 44, and the second molten salt reheater 44 is provided with an exhaust pipe to supply heat in the form of high-temperature steam, the rest are the same as in Embodiment 3.

[0131] This embodiment also provides a method for regenerative extraction steam energy storage to assist frequency modulation and peak load power generation, the method includes a frequency modulation operation method and a peak load operation method; the frequency modulation operation method is the same as that in Embodiment 2;

[0132] The peak load operation method is the same as that in Embodiment 3.

[0133] Embodiment 5

[0134] This embodiment provides a device system for regenerative extraction steam energy storage to assist frequency modulation and peak load power generation, and its structural schematic diagram is as Figure 5 shown.

[0135] Except that the second molten salt reheater 44 is arranged in series with the first molten salt reheater 43, the rest are the same as in Embodiment 4.

[0136] This embodiment also provides a method for regenerative extraction steam energy storage to assist frequency modulation and peak load power generation, and the method is the same as that in Embodiment 4.

[0137] In summary, the device system for regenerative extraction steam energy storage to assist frequency modulation and peak load power generation provided by the present invention, without affecting the efficiency of the thermal system, through regenerative extraction steam energy storage, enables the thermal power unit to obtain a more direct and rapid means of frequency modulation and load increase, and the load increase value reaches 2-5% of the rated output value of the steam turbine; the device system can store the sensible heat energy of the extraction steam during normal operation in the heat storage material and release it concentratedly during the peak load period, which can support the unit to obtain additional peak load operation ability; through the buffer of a safe and reliable heat storage system, it avoids the risk of life damage of equipment components caused by frequent temperature fluctuations during conventional feedwater frequency modulation, which is beneficial for the power plant to reduce the risk of unplanned shutdown and maintenance costs.

[0138] The applicant declares that the present invention uses the above embodiments to illustrate the detailed structural features of the present invention, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent replacement of the components selected by the present invention, the addition of auxiliary components, and the selection of specific methods, etc., all fall within the protection scope and the disclosure scope of the present invention.

[0139] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0140] In addition, it should be noted that, in the various specific technical features described in the above specific embodiments, they can be combined in any suitable manner without conflict. To avoid unnecessary repetition, the present invention will not separately describe various possible combination manners.

Claims

1. A device system for regenerative extraction steam energy storage assisted frequency modulation and peak shaving power generation, characterized in that The device system includes a boiler, a high-pressure cylinder of a steam turbine, an intermediate-pressure cylinder of the steam turbine, a low-pressure cylinder of the steam turbine, a condenser, a low-pressure heating device module, a deaerator, and a high-pressure heating device module that are connected in a cycle; The high-pressure cylinder of the steam turbine is connected to the heat storage material charging device through a first extraction steam pipeline or the intermediate-pressure cylinder of the steam turbine is connected to the heat storage material charging device through a second extraction steam pipeline; A first extraction steam frequency modulation valve is provided on the first extraction steam pipeline; a second extraction steam frequency modulation valve is provided on the second extraction steam pipeline; The heat storage material charging device is connected in a cycle with a first heat storage material storage device, a heat storage material heat release device, and a second heat storage material storage device; the heat storage material heat release device is respectively connected to the boiler and the high-pressure heating device module; a bypass feed water pipeline is provided between the heat storage material heat release device and the high-pressure heating device module; The number of high-pressure heaters in the high-pressure heating device module is 3 or 4.

2. The device system according to claim 1, characterized in that, The device system further includes an ultra-high-pressure cylinder of the steam turbine.

3. The device system according to claim 2, wherein The ultra-high-pressure cylinder of the steam turbine is respectively connected to the boiler and the high-pressure cylinder of the steam turbine.

4. The device system according to claim 2, characterized in that, The ultra-high-pressure cylinder of the steam turbine is connected to the high-pressure heating device module.

5. The device system according to claim 1, wherein The device system further includes a steam cooling device.

6. The device system according to claim 5, characterized in that, The steam cooling device is arranged between the high-pressure heating device module and the boiler.

7. The device system according to claim 5, characterized in that The steam cooling device is connected to the intermediate-pressure cylinder of the steam turbine.

8. The device system according to claim 1, wherein The heat storage material charging device is connected to the high-pressure heating device module.

9. The device system according to claim 1, wherein, The number of low-pressure cylinders of the steam turbine is at least 1.

10. The device system according to claim 1, characterized in that, The number of low-pressure heaters in the low-pressure heating device module is 4 or 5.

11. The device system according to claim 1, characterized in that, The number of heat storage material heat release devices is at least 1.

12. The device system according to claim 1, wherein The high-pressure cylinder of the steam turbine is respectively connected to the boiler and the high-pressure heating device module.

13. The device system according to claim 1, characterized in that, The intermediate-pressure cylinder of the steam turbine is respectively connected to the deaerator and the low-pressure heating device module.

14. The device system according to claim 1, characterized in that, The low-pressure cylinder of the steam turbine is connected to the low-pressure heating device module.

15. The device system according to claim 1, wherein, A condensate water conveying device is provided between the condenser and the low-pressure heating device module.

16. The device system according to claim 1, characterized in that, A feed water conveying device is provided between the deaerator and the high-pressure heating device module.

17. The device system according to claim 1, characterized in that, A first heat storage material conveying device is provided between the first heat storage material storage device and the heat storage material heat release device.

18. The device system according to claim 1, characterized in that, A second heat storage material conveying device is provided between the second heat storage material storage device and the heat storage material charging device.

19. The device system according to claim 1, characterized in that, A bypass feed water regulating valve is provided on the bypass feed water pipeline.

20. The device system according to claim 1, wherein, The device system further includes a power generation device.

21. The device system according to claim 20, characterized in that, The power generation device is connected to the low-pressure cylinder of the steam turbine.

22. A method for regenerative extraction steam energy storage to assist frequency regulation and peak shaving power generation, characterized in that, The method is carried out by using the regenerative extraction steam energy storage auxiliary frequency modulation and peak shaving power generation device system according to any one of claims 1 to 21, and the method includes a frequency modulation operation method and a peak shaving operation method.

23. The method according to claim 22, wherein The frequency modulation operation method includes: When the grid frequency drops to a first value and triggers a unit load increase command, the control system adjusts to reduce the opening of the first extraction steam frequency modulation valve, and the regenerative extraction steam returns to the high-pressure cylinder of the steam turbine to do work or reduces the opening of the second extraction steam frequency modulation valve, and the regenerative extraction steam returns to the intermediate-pressure cylinder of the steam turbine to do work; at the same time, the flow rate of the first heat storage material conveying device is increased to maintain the stable feed water temperature of the boiler.

24. The method according to claim 23, wherein After the frequency modulation operation is completed, the first extraction steam frequency modulation valve or the second extraction steam frequency modulation valve is fully opened, and the heat charging effect of the extraction steam on the heat storage material charging device is restored again.

25. The method according to claim 22, wherein The peak shaving operation method includes: During the peak operation period, the first extraction frequency modulation valve and the high-pressure heater supplied with extraction steam are shut down, so that the extraction steam does work in the high-pressure cylinder of the steam turbine, or the second extraction frequency modulation valve and the high-pressure heater supplied with extraction steam are shut down, so that the extraction steam does work in the intermediate-pressure cylinder of the steam turbine to support the peak operation of the unit load; increase the flow rate of the bypass feed water regulating valve and synchronously increase the flow rate of the first heat storage material conveying device to increase the peak operation capacity of the unit.

26. The method according to claim 23, wherein The first value is 49.967 Hz.

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