Thermal power generating unit peak regulation system and peak regulation method based on steam energy storage

Abstract

The invention relates to a thermal power generating unit peak shaving system and method based on steam energy storage, the thermal power generating unit peak shaving system comprises a steam turbine, a boiler and a water supply assembly, and the boiler comprises a main steam pipe and a reheat steam pipe; the water supply assembly comprises a water conveying assembly and a heating assembly; the thermal power generating unit peak shaving system further comprises a steam heat storage system. The steam heat storage system comprises a steam input assembly, a high-pressure steam heat accumulator and a low-pressure steam heat accumulator. The input end of the steam input assembly is at least connected with the output end of the main steam pipe, one output end of the steam input assembly is connected with the input end of the high-pressure steam heat accumulator, and the other output end of the steam input assembly is connected with the output end of the low-pressure steam heat accumulator; the output end of the high-pressure steam heat accumulator is connected with the heating assembly, the output end of the low-pressure steam heat accumulator is at least connected with the steam input end of the low-pressure cylinder, and the system has the advantages of being low in improvement cost, rapid in peak regulation response and wide in peak regulation range.

Description

Technical Field

[0001] The present invention relates to the technical field of peak regulation of power systems, and in particular to a peak regulation system and a peak regulation method for thermal power units based on steam energy storage. Background Art

[0002] The existing new energy power system, due to the randomness and volatility of new energy (wind energy, solar energy, etc.), has a series of problems in supply and demand balance, system regulation, stability characteristics, etc., which further leads to a low proportion of flexible power sources in the power grid.

[0003] In order to achieve load balance of new energy power systems, existing power systems are usually modified on the basis of the original systems. For example, molten salt energy storage systems, electrochemical energy storage systems, steam energy storage systems, etc. are added to the original power systems to achieve peak load regulation of the entire power system through energy storage and release of molten salt energy storage systems, electrochemical energy storage systems, and steam energy storage systems.

[0004] However, existing transformation plans usually find it difficult to meet the needs of rapid peak regulation and wide load peak regulation of the power system, and transformation plans represented by molten salt heat storage and electrochemical energy storage have high transformation costs. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the defects in the prior art, thereby providing a peak-shaving system and a peak-shaving method for a thermal power unit based on steam energy storage.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A peak-shaving system for a thermal power unit based on steam energy storage, comprising a steam turbine, a boiler for delivering steam to the steam turbine, and a water supply assembly for delivering water to the boiler, wherein the steam turbine comprises a high-pressure cylinder, an intermediate-pressure cylinder and a low-pressure cylinder; the boiler comprises a main steam pipe and a reheat steam pipe; the water supply assembly comprises a water supply assembly and a heating assembly, wherein the heating assembly is used to heat the water transported in the water supply assembly by using the extraction steam of the steam turbine; the peak-shaving system for a thermal power unit also comprises a steam heat storage system, wherein the steam heat storage system comprises a steam input assembly, a high-pressure steam accumulator and a low-pressure steam accumulator; the input end of the steam input assembly is at least connected to the output end of the main steam pipe, one of the output ends of the steam input assembly is connected to the input end of the high-pressure steam accumulator, and the other output end is connected to the input end of the low-pressure steam accumulator; the output end of the high-pressure steam accumulator is connected to the heating assembly, and the output end of the low-pressure steam accumulator is at least connected to the steam input end of the low-pressure cylinder.

[0008] Preferably, the steam input component includes a first check valve, a first regulating valve, a first temperature reducing and pressure reducing device, and a second temperature reducing and pressure reducing device; the output end of the main steam pipe, the first check valve, the first regulating valve, one of the output ends of the first temperature reducing and pressure reducing device, and the input end of the high-pressure steam accumulator are connected in sequence; the output end of the main steam pipe, the first check valve, the first regulating valve, the other output end of the first temperature reducing and pressure reducing device, the output end of the second temperature reducing and pressure reducing device, and the input end of the low-pressure steam accumulator are connected in sequence.

[0009] Preferably, the steam input component includes a first check valve, a first regulating valve, a first temperature and pressure reducing device and a pressure matcher; the output end of the main steam pipe, the first check valve, the first regulating valve, the first temperature and pressure reducing device, and the input end of the high-pressure steam accumulator are connected in sequence; the output end of the main steam pipe, the first check valve, the first regulating valve, the pressure matcher, and the input end of the low-pressure steam accumulator are connected in sequence; the steam input component also includes a second check valve and a second regulating valve, and the exhaust end of the high-pressure cylinder, the second check valve, the second regulating valve, the pressure matcher, and the input end of the low-pressure steam accumulator are connected in sequence.

[0010] Preferably, the steam heat storage system also includes a first pipe assembly; the output end of the high-pressure steam heat accumulator is connected to the heating assembly through the first pipe assembly; the first pipe assembly includes a third check valve and a third regulating valve, and the high-pressure steam heat accumulator, the third check valve, the third regulating valve and the heating assembly are connected in sequence; the heating assembly includes a plurality of high-pressure heaters, and the third regulating valve is arranged in a one-to-one correspondence with the high-pressure heaters.

[0011] Preferably, the steam heat storage system also includes a second pipe assembly; the output end of the low-pressure steam accumulator is connected to the steam input end of the low-pressure cylinder through the second pipe assembly; the second pipe assembly includes a fourth check valve, a fourth regulating valve and a pressure reducing valve; the output end of the low-pressure steam accumulator, the fourth check valve, the fourth regulating valve, the pressure reducing valve and the steam input end of the low-pressure cylinder are connected in sequence.

[0012] Preferably, the heating assembly includes a low-pressure heater; the steam heat storage system also includes a third pipe assembly; the third pipe assembly includes a fifth check valve and a fifth regulating valve; the output end of the low-pressure steam heat accumulator, the fifth check valve, the fifth regulating valve, and the steam input end of the low-pressure heater are connected in sequence.

[0013] A peak-shaving method based on the above-mentioned steam energy storage-based peak-shaving system of a thermal power unit comprises the following steps: when the unit reduces load, the main steam of the unit is transported to a steam input component for processing and then stored in a high-pressure steam accumulator and a low-pressure steam accumulator; when the unit increases load, the steam generated by the high-pressure steam accumulator is supplied to a heating component of a water supply component to replace at least part of the steam extracted from the high-pressure cylinder and the intermediate-pressure cylinder of the steam turbine by the heating component; when the unit increases load, the steam generated by the low-pressure steam accumulator and the exhaust steam of the intermediate-pressure cylinder are supplied to the low-pressure cylinder for use in the low-pressure cylinder to perform work.

[0014] Preferably, the method further comprises the following steps: when the unit increases load, the steam generated by the low-pressure steam accumulator is supplied to the heating component of the low-pressure cylinder supply water supply component to replace at least part of the steam extracted from the low-pressure cylinder of the steam turbine by the heating component.

[0015] Preferably, the steam generated by the high-pressure steam accumulator is supplied to the heating component of the water component to replace at least part of the steam extracted by the heating component from the high-pressure cylinder and the intermediate-pressure cylinder of the steam turbine; comprising the following steps: first, the steam generated by the high-pressure steam accumulator replaces the steam extracted by the heating component from the high-pressure cylinder; and then, the steam generated by the high-pressure steam accumulator replaces the steam extracted by the heating component from the intermediate-pressure cylinder.

[0016] Preferably, the method further comprises the following steps:

[0017] When the unit is de-loaded, the total flow of main steam delivered and stored in the high-pressure steam accumulator and / or the low-pressure steam accumulator is adjusted to adjust the load reduction rate of the unit;

[0018] When the unit increases its load, the steam flow rate delivered from the high-pressure steam accumulator to the heating component is adjusted, and / or the steam flow rate delivered from the low-pressure steam accumulator to the low-pressure cylinder and / or the heating component is adjusted to adjust the load increase rate of the unit.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The above technical solution provides a peak-shaving system for thermal power units based on steam energy storage, which connects the input end of the steam input component to the output end of the main steam pipe, connects one of the output ends of the steam input component to the input end of the high-pressure steam accumulator, and connects the other output end to the output end of the low-pressure steam accumulator. At the same time, the output end of the high-pressure steam accumulator is connected to the heating component, and the output end of the low-pressure steam accumulator is connected to the steam input end of the low-pressure cylinder. When the unit has a rapid load reduction demand, the high-temperature and high-pressure steam output from the main steam pipe can be stored in multiple stages, that is, after being processed by the steam input component, it is stored in the high-pressure steam accumulator and the low-pressure steam accumulator respectively, which can not only quickly reduce the amount of steam supplied to the high-pressure cylinder of the turbine, thereby quickly reducing the output power of the turbine, but also store the energy of the high-temperature and high-pressure steam output from the main steam pipe to avoid energy waste. When the unit has a rapid load increase demand, the high-pressure water in the high-pressure steam accumulator is converted into steam to supply the heating component, replacing at least part of the steam extraction of the turbine to preheat the water sent to the boiler, which can not only meet the water preheating demand, but also reduce the steam extraction amount of the turbine, thereby quickly increasing the turbine output power. In addition, the high-pressure water stored in the low-pressure steam accumulator can be converted into steam to supply the low-pressure cylinder. At the same time, the exhaust steam of the medium-pressure cylinder is also supplied to the low-pressure cylinder, thereby increasing the steam intake of the low-pressure cylinder, and further cooperating with the high-pressure steam accumulator to quickly increase the output power of the turbine. In addition, in this scheme, the peak-shaving range of the entire unit can be effectively increased through the mutual cooperation of the turbine, the water supply component, the main steam pipe, the high-pressure steam accumulator, and the low-pressure steam accumulator. Correspondingly, the peak-shaving method of the peak-shaving system of the thermal power unit based on the above-mentioned steam energy storage has the advantages of low transformation cost, fast peak-shaving response and wide peak-shaving range. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a schematic diagram of a first embodiment of the present invention.

[0023] Figure 2 It is a schematic diagram of a second embodiment of the present invention.

[0024] Figure 3 It is a schematic diagram of a third embodiment of the present invention.

[0025] Figure 4It is the output power of the steam thermal storage system during the unit load increase period provided by the embodiment of the present invention.

[0026] Figure 5 It is a schematic diagram of the steam generation and power generation distribution of the steam thermal storage system under different system operating conditions provided by an embodiment of the present invention.

[0027] Description of reference numerals:

[0028] 1. Steam turbine; 11. High-pressure cylinder; 12. Intermediate-pressure cylinder; 13. Low-pressure cylinder; 2. Boiler; 21. Main steam pipe; 22. Reheat steam pipe; 3. Feedwater assembly; 31. Water delivery assembly; 311. Delivery pipe; 312. Condenser; 313. Condensate pump; 314. Deaerator; 315. Feedwater pump; 32. Heating assembly; 321. First high-pressure heater; 322. Second high-pressure heater; 323. Third high-pressure heater; 324. Low-pressure heater; 4. Steam thermal storage system; 41. Steam input assembly; 411. First check valve; 412. First regulating valve; 41 3. First temperature reducing and pressure reducing device; 414. Second temperature reducing and pressure reducing device; 415. Second check valve; 416. Second regulating valve; 417. Pressure matching device; 42. High-pressure steam accumulator; 43. Low-pressure steam accumulator; 44. First pipe assembly; 441. Third check valve; 442. Third regulating valve; 45. Second pipe assembly; 451. Fourth check valve; 452. Fourth regulating valve; 453. Pressure reducing valve; 46. Third pipe assembly; 461. Fifth check valve; 462. Fifth regulating valve; 5. Pipe fitting; 51. Sixth check valve; 6. First steam extraction valve; 7. Second steam extraction valve. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] Embodiment 1

[0033] See also Figure 1 An embodiment of the present invention provides a peak-shaving system for a thermal power unit based on steam energy storage, comprising a steam turbine 1, a boiler 2 and a water supply component 3; wherein the boiler 2 is used to transport steam to the steam turbine 1 to drive the steam turbine 1 to generate power, and the water supply component 3 is used to transport water to the boiler 2 to form steam.

[0034] Specifically, the steam turbine 1 includes a high-pressure cylinder 11, an intermediate-pressure cylinder 12 and a low-pressure cylinder 13, and the boiler 2 includes a main steam pipe 21 and a reheat steam pipe 22. Among them, the main steam pipe 21 provides high-temperature and high-pressure hot steam, which is mainly used for the high-pressure cylinder 11 of the steam turbine 1; the reheat steam pipe 22 provides high-temperature and high-pressure hot steam that is heated for the second time, which is mainly used to supply the intermediate-pressure cylinder 12. The input end of the reheat steam pipe 22 is connected to the exhaust end of the high-pressure cylinder 11, so that the exhaust steam of the high-pressure cylinder 11 is heated by the reheat steam pipe 22 of the boiler 2 and then supplied to the intermediate-pressure cylinder 12. The water supply component 3 includes a water supply component 31 and a heating component 32. The heating component 32 is used to heat the water transported in the water supply component 31 using the extraction steam of the steam turbine 1, which can not only realize the peak load regulation of the unit, but also preheat the water entering the boiler 2.

[0035] In order to meet the demand for rapid peak load regulation, in this embodiment, the peak load regulation system of the thermal power unit further includes a steam heat storage system 4 .

[0036] Specifically, the steam heat storage system 4 includes a steam input component 41, a high-pressure steam accumulator 42 and a low-pressure steam accumulator 43; the input end of the steam input component 41 is connected to at least the output end of the main steam pipe 21, one of the output ends of the steam input component 41 is connected to the input end of the high-pressure steam accumulator 42, and the other output end is connected to the output end of the low-pressure steam accumulator 43; the output end of the high-pressure steam accumulator 42 is connected to the heating component 32, and the output end of the low-pressure steam accumulator 43 is connected to at least the steam input end of the low-pressure cylinder 13.

[0037] By connecting the input end of the steam input component 41 to the output end of the main steam pipe 21, connecting one of the output ends of the steam input component 41 to the input end of the high-pressure steam accumulator 42, and connecting the other output end to the output end of the low-pressure steam accumulator 43, at the same time, connecting the output end of the high-pressure steam accumulator 42 to the heating component 32, and connecting the output end of the low-pressure steam accumulator 43 to the steam input end of the low-pressure cylinder 13; when the unit has a rapid load reduction demand, the high-temperature and high-pressure steam output from the main steam pipe 21 can be stored in multiple stages, that is, after being processed by the steam input component 41, it is stored in the high-pressure steam accumulator 42 and the low-pressure steam accumulator 43 respectively, which can not only quickly reduce the amount of steam supplied to the high-pressure cylinder 11 of the steam turbine 1, thereby quickly reducing the output power of the steam turbine 1, but also can store the energy of the high-temperature and high-pressure steam output from the main steam pipe 21 to avoid energy waste. When the unit has a demand for rapid load increase, the high-pressure water in the high-pressure steam accumulator 42 is converted into steam and supplied to the heating component 32, so as to replace at least part of the steam extraction of the steam turbine 1 to preheat the water sent to the boiler 2, which can not only meet the demand for preheating the water sent to the boiler 2, but also reduce the steam extraction amount of the steam turbine 1, thereby quickly increasing the output power of the steam turbine 1. In addition, the high-pressure water stored in the low-pressure steam accumulator 43 can also be converted into steam and supplied to the low-pressure cylinder 13. At the same time, the exhaust steam of the medium-pressure cylinder 12 is also supplied to the low-pressure cylinder 13, thereby increasing the steam intake of the low-pressure cylinder 13, and further cooperating with the high-pressure steam accumulator 42 to quickly increase the output power of the steam turbine 1.

[0038] As can be seen from the above, in this solution, the peak load regulation range of the entire unit can be effectively increased through the cooperation of the steam turbine 1, the water supply assembly 3, the main steam pipe 21, the high-pressure steam accumulator 42, and the low-pressure steam accumulator 43. In addition, the entire steam heat storage system 4 has a simple structure, and when it is modified based on the original power system, the modification cost is lower.

[0039] See also Figure 1 In this embodiment, the steam input component 41 includes a first check valve 411 , a first regulating valve 412 , a first temperature reducing and pressure reducing device 413 , and a second temperature reducing and pressure reducing device 414 .

[0040] Specifically, the output end of the main steam pipe 21, the first check valve 411, the first regulating valve 412, one of the output ends of the first temperature reducing and pressure reducing device 413, and the input end of the high-pressure steam accumulator 42 are connected in sequence. The output end of the main steam pipe 21, the first check valve 411, the first regulating valve 412, the other output end of the first temperature reducing and pressure reducing device 413, the second temperature reducing and pressure reducing device 414, and the low-pressure steam accumulator 43 are connected in sequence. It can be known that when the unit reduces the load, the first check valve 411 and the first regulating valve 412 are opened, and the high-parameter (such as high temperature and high pressure) steam output from the output end of the main steam pipe 21 passes through the first check valve 411, the first regulating valve 412, and the first temperature and pressure reducer 413 in sequence, and is divided into two paths after being cooled and reduced in pressure by the first temperature and pressure reducer 413. One path is input into the high-pressure steam accumulator 42 for storage through one of the output ends; the other path is input into the second temperature and pressure reducer 414 through another output end, and is stored in the low-pressure steam accumulator 43 after being cooled and reduced in pressure by the second temperature and pressure reducer 414.

[0041] See also Figure 1 There are many ways to connect the output end of the high-pressure steam accumulator 42 and the heating component 32. In this embodiment, the steam thermal storage system 4 also includes a first pipe assembly 44; the output end of the high-pressure steam accumulator 42 and the heating component 32 are connected through the first pipe assembly 44.

[0042] Specifically, the first pipe assembly 44 includes a third check valve 441 and a third regulating valve 442, and the high-pressure steam accumulator 42, the third check valve 441, the third regulating valve 442 and the heating assembly 32 are connected in sequence; the heating assembly 32 includes a plurality of high-pressure heaters, and the third regulating valve 442 is arranged one by one with the high-pressure heaters.

[0043] Furthermore, in this embodiment, the high-pressure heater includes a first high-pressure heater 321, a second high-pressure heater 322 and a third high-pressure heater 323 which are connected in sequence along the water supply direction of the water supply component 31, and three corresponding third regulating valves 442 are also provided, which are respectively connected to the first high-pressure heater 321, the second high-pressure heater 322 and the third high-pressure heater 323. When the unit increases its load, first, the third check valve 441 and the third regulating valve 442 correspondingly connected to the third high-pressure heater 323 are opened, and the steam generated by the high-pressure steam accumulator 42 is transported to the third high-pressure heater 323 after passing through the third check valve 441 and the third regulating valve 442 correspondingly connected to the third high-pressure heater 323 in sequence; then, when there is surplus steam generated by the high-pressure steam accumulator 42 (for example, there is surplus steam after the steam generated by the high-pressure steam accumulator 42 completely replaces the steam extracted from the high-pressure cylinder 11 by the third high-pressure heater 323), the third regulating valve 442 correspondingly connected to the second high-pressure heater 322 is opened; finally, similarly, if there is surplus steam generated by the high-pressure steam accumulator 42, the third regulating valve 442 correspondingly connected to the first high-pressure heater 321 is opened.

[0044] It is worth noting that, in this embodiment, three high-pressure heaters are used as an example. In other embodiments, multiple heaters may be provided, and priority is given to ensuring that the steam generated by the high-pressure steam accumulator 42 is supplied to the high-pressure heater downstream (i.e., downstream of the water supply direction of the water supply component 31). Correspondingly, it can be known that, in order to meet the steam extraction control, a first steam extraction valve 6 is also provided between the steam extraction end of the steam turbine 1 and the heating component 32. When the steam extracted from the steam turbine 1 by the heating component 32 can be completely replaced by the steam generated by the high-pressure steam accumulator 42, the first steam extraction valve 6 can remain closed to improve the output efficiency of the steam turbine 1.

[0045] See also Figure 1 There are many ways to connect the output end of the low-pressure steam accumulator 43 with the steam input end of the low-pressure cylinder 13. In this embodiment, the steam thermal storage system 4 also includes a second pipe assembly 45; the output end of the low-pressure steam accumulator 43 is connected to the steam input end of the low-pressure cylinder 13 through the second pipe assembly 45.

[0046] Specifically, the second pipe assembly 45 includes a fourth check valve 451, a fourth regulating valve 452, and a pressure reducing valve 453; the output end of the low-pressure steam accumulator 43, the fourth check valve 451, the fourth regulating valve 452, the pressure reducing valve 453 and the steam input end of the medium-pressure cylinder 12 are connected in sequence.

[0047] Furthermore, the pipe fitting 5 is provided between the medium-pressure cylinder 12 and the low-pressure cylinder 13 . The pipe fitting 5 is provided with a sixth check valve 51 . The downstream of the sixth check valve 51 is connected to the second pipe assembly 45 .

[0048] When the unit increases its load, the fourth check valve 451, the fourth regulating valve 452, the pressure reducing valve 453 and the sixth check valve 51 are all opened. At this time, the steam output from the output end of the low-pressure steam accumulator 43 is transported to the low-pressure cylinder 13 through the fourth check valve 451, the fourth regulating valve 452 and the pressure reducing valve 453. The fourth check valve 451 can prevent the steam from flowing back, and the sixth check valve 51 can prevent the steam from flowing back to the medium-pressure cylinder 12.

[0049] The water supply assembly 3 can be set to a variety of structures, which can deliver water to the boiler 2 and preheat the water during the water delivery process.

[0050] See also Figure 1 In this embodiment, the heating assembly 32 includes a plurality of first high-pressure heaters 321, second high-pressure heaters 322, and third high-pressure heaters 323 connected in sequence along the water supply direction; wherein the steam input end of the first high-pressure heater 321 is connected to the steam extraction end of the intermediate pressure cylinder 12, so as to use the steam extraction of the intermediate pressure cylinder 12 to heat the water transported in the water supply assembly 31; the second high-pressure heater 322 is connected to the first steam extraction end of the high-pressure cylinder 11, and the third high-pressure heater 323 is connected to the second steam extraction end of the high-pressure cylinder 11, and the steam temperature of the first steam extraction end of the high-pressure cylinder 11 is lower than the steam temperature of the second steam extraction end of the high-pressure cylinder 11, so as to use the steam extraction of the high-pressure cylinder 11 to heat the water transported in the water supply assembly 31. It can be known that in the above embodiment, the steam temperatures input into the first high-pressure heater 321, the second high-pressure heater 322, and the third high-pressure heater 323 are increased in sequence, so as to realize the step heating of the water transported in the water supply assembly 31, so as to increase the heat exchange efficiency.

[0051] Furthermore, the heating assembly 32 also includes a low-pressure heater 324 located upstream of the first high-pressure heater 321 (i.e., upstream along the water delivery direction), and the steam input end of the low-pressure heater 324 is connected to the steam extraction end of the low-pressure cylinder 13 to utilize the steam in the low-pressure cylinder 13 to heat the water transported in the water delivery assembly 31.

[0052] Furthermore, in order to realize the reuse of the steam in the low-pressure cylinder 13, in this embodiment, the water delivery assembly 31 includes a delivery pipe 311, a condenser 312, a condensate pump 313, a deaerator 314 and a feed water pump 315. It can be known that there are multiple delivery pipes 311 for delivering water and various components.

[0053] Specifically, from the exhaust end of the low-pressure cylinder 13 to the direction of the boiler 2, a plurality of delivery pipes 311 sequentially connect the exhaust end of the low-pressure cylinder 13, the condenser 312, the condensate pump 313, the low-pressure heater 324, the deaerator 314, the feed water pump 315, the first high-pressure heater 321, the second high-pressure heater 322, the third high-pressure heater 323 and the boiler 2 to form a water supply path for the boiler 2.

[0054] Embodiment 2

[0055] See also Figure 2 Based on the above embodiment 1, in this embodiment, the steam thermal storage system 4 also includes a third pipe assembly 46; the third pipe assembly 46 includes a fifth check valve 461 and a fifth regulating valve 462; the output end of the low-pressure steam thermal accumulator 43, the fifth check valve 461, the fifth regulating valve 462, and the steam input end of the low-pressure heater 324 are connected in sequence.

[0056] When the unit increases its load, the fifth check valve 461 and the fifth regulating valve 462 are opened, and the steam output from the low-pressure steam accumulator 43 is transported to the steam input end of the low-pressure heater 324 through the fifth check valve 461 and the fifth regulating valve 462, replacing the low-pressure heater 324 to extract steam from the low-pressure cylinder 13, and heats the condensate (the water transported in the delivery pipe 311 of the water delivery component 31), which can increase the output power of the low-pressure cylinder 13 to a certain extent.

[0057] Correspondingly, it can be known that a second steam extraction valve 7 is provided between the connecting pipe between the low-pressure heater 324 and the low-pressure cylinder 13. When the steam output by the low-pressure steam accumulator 43 can replace the steam extracted from the low-pressure cylinder 13 by the low-pressure heater 324, the second steam extraction valve 7 is closed.

[0058] Embodiment 3

[0059] See also Figure 3 Based on the above-mentioned embodiment 2, the difference of this embodiment is that: the steam input component 41 includes a first check valve 411, a first regulating valve 412, a first temperature and pressure reducing device 413 and a pressure matching device 417; the output end of the main steam pipe 21, the first check valve 411, the first regulating valve 412, the first temperature and pressure reducing device 413, and the input end of the high-pressure steam accumulator 42 are connected in sequence; the output end of the main steam pipe 21, the first check valve 411, the first regulating valve 412, the pressure matching device 417, and the input end of the low-pressure steam accumulator 43 are connected in sequence; the steam input component 41 also includes a second check valve 415 and a second regulating valve 416, and the exhaust end of the high-pressure cylinder 11, the second check valve 415, the second regulating valve 416, the pressure matching device 417, and the input end of the low-pressure steam accumulator 43 are connected in sequence.

[0060] It can be known that when the unit is under load reduction, the first check valve 411, the first regulating valve 412, the second check valve 415 and the second regulating valve 416 are all open, and the high-parameter (such as high temperature and high pressure) steam output from the output end of the main steam pipe 21 can be divided into two paths after passing through the first check valve 411 and the first regulating valve 412, one of which is transported to the high-pressure steam accumulator 42 for storage after being reduced in temperature and pressure by the first temperature and pressure reducing device 413, and the other is transported to the low-pressure steam accumulator 43 for storage through the pressure matching device 417. At the same time, the exhaust steam of the high-pressure cylinder 11 is transported to the pressure matching device 417 after passing through the second check valve 415 and the second regulating valve 416, and is transported to the low-pressure steam accumulator 43 through the pressure matching device 417. It can be known that the high-pressure steam delivered from the first check valve 411 and the first regulating valve 412, and the relatively low-pressure steam delivered from the second check valve 415 and the second regulating valve 416 are input into the low-pressure steam accumulator 43 after pressure matching by the pressure matcher 417. This method can reduce the amount of main steam supplied to the high-pressure cylinder 11, store the exhaust steam of the high-pressure cylinder 11, reduce the amount of steam supplied from the high-pressure cylinder 11 to the intermediate-pressure cylinder 12 through the reheat steam pipe 22, and thus quickly reduce the output power of the steam turbine 1.

[0061] In addition, by controlling the opening of the first regulating valve 412 and the second regulating valve 416, the steam supply to the high-pressure cylinder 11 and the steam supply to the medium-pressure cylinder 12 can be controlled, thereby meeting different load requirements of the unit and increasing the peak-shaving range of the unit.

[0062] It is worth noting that the above system structures are connected via pipelines, and the corresponding valve structures are arranged on the pipelines.

[0063] Embodiment 4

[0064] Based on the above embodiment, this embodiment further provides a peak shaving method comprising the following steps:

[0065] When the unit is deloaded, the main steam of the unit is transported to the steam input assembly 41 for processing and then stored in the high-pressure steam accumulator 42 and the low-pressure steam accumulator 43;

[0066] When the unit is loaded, the steam generated by the high-pressure steam accumulator 42 is supplied to the heating assembly 32 of the feedwater assembly 3 to replace at least part of the steam extracted by the heating assembly 32 from the high-pressure cylinder 11 and the intermediate-pressure cylinder 12 of the steam turbine 1;

[0067] When the unit is loaded, the steam generated by the low-pressure steam accumulator 43 and the exhaust steam of the intermediate-pressure cylinder 12 are supplied to the low-pressure cylinder 13 so that the low-pressure cylinder 13 can perform work.

[0068] Specifically, the steam generated by the high-pressure steam accumulator 42 is supplied to the heating component 32 of the feedwater component 3 to replace at least part of the steam extracted from the high-pressure cylinder 11 and the intermediate-pressure cylinder 12 of the steam turbine 1 by the heating component 32; the following steps are included:

[0069] First, the steam generated by the high-pressure steam accumulator 42 replaces the steam extracted from the high-pressure cylinder 11 by the heating component 32;

[0070] The steam generated by the high-pressure steam accumulator 42 is then used to replace the steam extracted from the intermediate-pressure cylinder 12 by the heating component 32 .

[0071] The peak-shaving method also includes the following steps: when the unit increases its load, the steam generated by the low-pressure steam accumulator 43 is supplied to the low-pressure cylinder 13 to supply the heating component 32 (specifically the low-pressure heater 324) of the water supply component 3, so as to replace at least part of the steam extraction of the heating component 32 from the low-pressure cylinder 13 of the turbine 1.

[0072] Furthermore, in order to meet the requirements for adjusting the load rate and range of the unit, in this embodiment, the method further includes the following steps:

[0073] When the unit is deloaded, the total flow of the main steam delivered and stored in the high-pressure steam accumulator 42 and the low-pressure steam accumulator 43 is adjusted to adjust the load reduction rate of the unit. Specifically, when the unit is deloaded, the total flow of the main steam delivered to the high-pressure steam accumulator 42 and the low-pressure steam accumulator 43 can be adjusted. When the total flow of the main steam in this part is relatively large (accounting for a large proportion of the main steam flow output by the boiler 2), the amount of main steam delivered to the intermediate pressure cylinder 12 by the boiler 2 is rapidly reduced, and the amount of steam reduced is relatively large, so that the load reduction rate can be quickly adjusted. When the total flow of the main steam in this part is relatively small (accounting for a small proportion of the main steam flow output by the boiler 2), the amount of main steam delivered to the intermediate pressure cylinder 12 by the boiler 2 is relatively small, and the load reduction rate of the unit is slow.

[0074] Furthermore, in order to meet the requirements for adjusting the load rate and range of the unit, in this embodiment, the method further includes the following steps:

[0075] When the unit is loaded, the steam flow rate delivered from the high-pressure steam accumulator 42 to the heating component 32 is adjusted to adjust the load increase rate of the component.

[0076] When the unit increases its load, the steam flow from the low-pressure steam accumulator 43 to the low-pressure cylinder 13 can be adjusted, and the steam flow from the low-pressure steam accumulator 43 to the heating component 32 can be adjusted to adjust the load increase rate of the unit.

[0077] It can be known that the specific flow rate adjustment method can be adjusted according to the actual needs of the corresponding valve opening. In addition, when the unit is loaded, the steam flow rate delivered to the heating component 32 by the high-pressure steam accumulator 42 can be adjusted to adjust the load rate of the unit. At the same time, the steam flow rate delivered to the low-pressure cylinder 13 and the heating component 32 by the low-pressure steam accumulator 43 can be adjusted to adjust the load rate of the unit, for example, when rapid adjustment is required. Of course, in other embodiments, only the steam flow rate delivered by the high-pressure steam accumulator 42 can be adjusted. It is also possible to first adjust the steam flow rate delivered by the high-pressure steam accumulator 42, and then adjust the steam flow rate delivered by the low-pressure steam accumulator 43. The steam of the low-pressure steam accumulator 43 can also be supplied only to the low-pressure cylinder 13, and can also be supplied only to the heating component 32. It can be selected according to actual needs to adjust the peak rate.

[0078] An example is given based on the actual application of the above-mentioned embodiment 1. When the existing thermal power unit is actually improved according to the embodiment 1, a typical 300MW subcritical unit is taken as an example. In order to achieve the variable load rate target of more than 5% / min, the boiler 2 side can achieve a variable load rate capacity of 2.5-3% / min after optimization, and the comprehensive heat storage regulation on the turbine 1 side can reach a variable load rate capacity of 0-0.5% / min. By adding a steam heat storage system 4, a variable load rate regulation of 2.5-3% / min can be achieved.

[0079] The overall design idea of ​​the steam thermal storage system 4 is to meet the main AGC instruction application scenarios and the variable load requirements of the steam turbine 1 side, determine the continuous operation time of the thermal power unit with rapid load changes, and then determine the amount of steam required to be provided by the steam thermal storage system 4 based on the work increment of the steam turbine 1, and finally determine the basic design parameters of the steam thermal storage system 4. Through AGC scenario analysis of the AGC instruction data of representative power plants, the steam capacity corresponding to 15% Pe is selected for the design of the steam thermal storage device to meet most application scenarios.

[0080] See also Figure 4 , Figure 4 The transient characteristics of steam supply and power generation of the 300MW subcritical unit coupled with the steam thermal storage system 4 during the process of the system increasing from 30% Pe to 45% Pe; the unit completed the load increase operation in 3 minutes, and the steam supply of the steam thermal storage system 4 gradually increased in the first 3 minutes, among which the steam production reached the peak at the 3rd minute, corresponding to the electric power of 27MW; after that, the steam thermal storage system 4 continued to supply steam to the outside, and the steam supply gradually decreased until the steam production of the boiler 2 reached the stable load level.

[0081] From the above example, it can be seen that the steam generated by the steam thermal storage system 4 can be used in the following ways:

[0082] The high-pressure heater feed water of the heating assembly 32 is used to heat the steam, thereby reducing or replacing the extraction of steam from the high-pressure cylinder 11 and the intermediate-pressure cylinder 12 of the steam turbine 1 by the heating assembly 32 .

[0083] The low-pressure cylinder 13 is directly supplied with power for generating work.

[0084] The low-pressure heater 324 of the heating assembly 32 is used to heat the feed water, thereby reducing or replacing the extraction of steam from the low-pressure cylinder 13 of the steam turbine 1 by the low-pressure heater 324 of the heating assembly 32 .

[0085] Through the coordination of various methods and the adjustment of steam volume, the steam accumulator steam production distribution ratio can be adjusted differently under different operating loads of the unit. Figure 5 , Figure 5 The above differences are quantitatively demonstrated. The instantaneous maximum steam production capacity of the steam thermal storage system 4 can reach 27MW corresponding to the steam flow rate. When the unit is under low load, the steam extraction amount of the high-pressure heater is relatively small, and the corresponding power generation amount cannot meet the load increase demand of the unit. Therefore, most of the steam produced by the steam thermal storage system 4 needs to be allocated to the low-pressure cylinder 13 for direct power generation; as the unit load increases, the demand for high-pressure steam increases, and the steam production of the steam thermal storage system 4 can be allocated more to the heating component 32 (prioritizing the high-pressure heater), and the amount of steam allocated to the low-pressure cylinder 13 gradually decreases.

[0086] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A peak load regulation system for a thermal power unit based on steam energy storage, comprising a steam turbine (1), a boiler (2) for delivering steam to the steam turbine (1), and a water supply assembly (3) for delivering water to the boiler (2), wherein the steam turbine (1) comprises a high-pressure cylinder (11), a medium-pressure cylinder (12), and a low-pressure cylinder (13); It is characterized in that The boiler (2) comprises a main steam pipe (21) and a reheat steam pipe (22); The water supply component (3) comprises a water supply component (31) and a heating component (32), wherein the heating component (32) is used to heat the water transported in the water supply component (31) by utilizing the extraction steam of the steam turbine (1); The thermal power unit peak load regulation system further comprises a steam heat storage system (4), wherein the steam heat storage system (4) comprises a steam input component (41), a high-pressure steam heat storage device (42) and a low-pressure steam heat storage device (43); The input end of the steam input component (41) is connected to at least the output end of the main steam pipe (21), one of the output ends of the steam input component (41) is connected to the input end of the high-pressure steam accumulator (42), and the other output end is connected to the input end of the low-pressure steam accumulator (43); The output end of the high-pressure steam accumulator (42) is connected to the heating component (32), and the output end of the low-pressure steam accumulator (43) is at least connected to the steam input end of the low-pressure cylinder (13).

2. A peak load regulation system for thermal power units based on steam energy storage according to claim 1, characterized in that: The steam input component (41) comprises a first check valve (411), a first regulating valve (412), a first temperature reducing and pressure reducing device (413) and a second temperature reducing and pressure reducing device (414); The output end of the main steam pipe (21), the first check valve (411), the first regulating valve (412), one of the output ends of the first temperature reducing and pressure reducing device (413), and the input end of the high-pressure steam accumulator (42) are connected in sequence; The output end of the main steam pipe (21), the first check valve (411), the first regulating valve (412), the other output end of the first temperature reducing and pressure reducing device (413), the output end of the second temperature reducing and pressure reducing device (414), and the input end of the low-pressure steam accumulator (43) are connected in sequence.

3. A peak load regulation system for thermal power units based on steam energy storage according to claim 1, characterized in that: The steam input component (41) comprises a first check valve (411), a first regulating valve (412), a first temperature and pressure reducing device (413) and a pressure matching device (417); The output end of the main steam pipe (21), the first check valve (411), the first regulating valve (412), the first temperature and pressure reducing device (413), and the input end of the high-pressure steam accumulator (42) are connected in sequence; The output end of the main steam pipe (21), the first check valve (411), the first regulating valve (412), the pressure matching device (417), and the input end of the low-pressure steam accumulator (43) are connected in sequence; The steam input component (41) further comprises a second check valve (415) and a second regulating valve (416); the exhaust end of the high-pressure cylinder (11), the second check valve (415), the second regulating valve (416), the pressure matcher (417), and the input end of the low-pressure steam accumulator (43) are connected in sequence.

4. A peak load regulation system for thermal power units based on steam energy storage according to any one of claims 1 to 3, characterized in that: The steam thermal storage system (4) further comprises a first pipe assembly (44); The output end of the high-pressure steam accumulator (42) is connected to the heating component (32) via the first pipe component (44); The first pipe assembly (44) comprises a third check valve (441) and a third regulating valve (442), and the high-pressure steam accumulator (42), the third check valve (441), the third regulating valve (442) and the heating assembly (32) are connected in sequence; The heating assembly (32) includes a plurality of high-pressure heaters, and the third regulating valves (442) are arranged in a one-to-one correspondence with the high-pressure heaters.

5. A peak load regulation system for thermal power units based on steam energy storage according to any one of claims 1 to 3, characterized in that: The steam thermal storage system (4) further comprises a second pipe assembly (45); The output end of the low-pressure steam accumulator (43) is connected to the steam input end of the low-pressure cylinder (13) via the second pipe assembly (45); The second pipe assembly (45) includes a fourth check valve (451), a fourth regulating valve (452) and a pressure reducing valve (453); The output end of the low-pressure steam accumulator (43), the fourth check valve (451), the fourth regulating valve (452), the pressure reducing valve (453), and the steam input end of the low-pressure cylinder (13) are connected in sequence.

6. A peak load regulation system for thermal power units based on steam energy storage according to any one of claims 1 to 3, characterized in that: The heating assembly (32) includes a low-pressure heater (324); The steam thermal storage system (4) further comprises a third pipe assembly (46); The third pipe assembly (46) includes a fifth check valve (461) and a fifth regulating valve (462); The output end of the low-pressure steam accumulator (43), the fifth check valve (461), the fifth regulating valve (462), and the steam input end of the low-pressure heater (324) are connected in sequence.

7. A peak-shaving method for a peak-shaving system of a thermal power unit based on steam energy storage according to any one of claims 1 to 6, characterized in that: The following steps are involved: When the unit is de-loaded, the main steam of the unit is transported to the steam input component (41) for processing and then stored in the high-pressure steam accumulator (42) and the low-pressure steam accumulator (43); When the unit is loaded, the steam generated by the high-pressure steam accumulator (42) is supplied to the heating component (32) of the water supply component (3) to replace at least part of the steam extracted by the heating component (32) from the high-pressure cylinder (11) and the intermediate-pressure cylinder (12) of the steam turbine (1); When the unit is loaded, the steam generated by the low-pressure steam accumulator (43) and the exhaust steam of the intermediate-pressure cylinder (12) are supplied to the low-pressure cylinder (13) so as to enable the low-pressure cylinder (13) to perform work.

8. The peak load regulation method according to claim 7, characterized in that: The following steps are also included: When the unit is loaded, the steam generated by the low-pressure steam accumulator (43) is supplied to the heating component (32) of the water supply component (3) to replace at least part of the steam extracted by the heating component (32) from the low-pressure cylinder (13) of the steam turbine (1).

9. The peak load regulation method according to claim 7, characterized in that: The method of supplying the steam generated by the high-pressure steam accumulator (42) to the heating component (32) of the water supply component (3) to replace at least part of the steam extracted by the heating component (32) from the high-pressure cylinder (11) and the intermediate-pressure cylinder (12) of the steam turbine (1) comprises the following steps: First, the steam generated by the high-pressure steam accumulator (42) replaces the steam extracted from the high-pressure cylinder (11) by the heating component (32); The steam generated by the high-pressure steam accumulator (42) is then used to replace the steam extracted from the intermediate-pressure cylinder (12) by the heating component (32).

10. The peak load regulation method according to claim 8, characterized in that: The following steps are also included: When the unit is de-loaded, the total flow of main steam delivered and stored in the high-pressure steam accumulator (42) and / or the low-pressure steam accumulator (43) is adjusted to adjust the rate of de-load of the unit; When the load of the unit is increased, the steam flow rate delivered from the high-pressure steam accumulator (42) to the heating component (32) is adjusted, and / or the steam flow rate delivered from the low-pressure steam accumulator (43) to the low-pressure cylinder (13) and / or the heating component (32) is adjusted to adjust the load increase rate of the unit.

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