A full-operation-condition coupled molten salt heat storage thermal power unit peak regulation system and operation method

Abstract

The present invention relates to a full-operation-condition coupled molten salt heat storage peak-shaving system for a thermal power unit and an operating method thereof, comprising a unit thermal system and a molten salt heat storage and release system; the unit thermal system comprises a boiler, a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder, a condenser, a low-temperature steam heater group, a deaerator, a high-temperature steam heater group, and a generator; the boiler is connected to a main steam pipeline and a reheat hot section pipeline, the main steam pipeline is connected to the high-pressure cylinder inlet, and the reheat hot section pipeline outlet is connected to the intermediate-pressure cylinder; the salt storage and release system comprises a low-temperature molten salt tank, an intermediate-temperature molten salt tank, a high-temperature molten salt tank, a first high-temperature molten salt steam heat exchanger, a first intermediate-temperature molten salt steam heat exchanger, a second high-temperature molten salt steam heat exchanger, a second intermediate-temperature molten salt steam heat exchanger, and an electric heater. By providing a bypass molten salt heat storage and release system, the system can flexibly switch the heat storage and release process according to the characteristics of the external heat load and electrical load, resulting in a faster unit peak-shaving response speed and better full-operation-condition peak-shaving flexibility.

Description

Technical Field

[0001] The present invention relates to the field of peak regulation of thermal power generation units, and in particular to a full-operating-condition coupled molten salt heat storage thermal power generation unit peak regulation system and an operating method. Background Art

[0002] With the rapid transformation of my country's energy structure, the installed capacity and proportion of new energy such as wind power and photovoltaics have increased rapidly. The large-scale construction and commissioning of new energy have put forward higher requirements on the peak-shaving and flexibility capabilities of thermal power generating units.

[0003] Currently, my country's coal-fired power generation thermal power decoupling and flexibility improvement technologies primarily fall into two categories: unit-level modifications and energy storage modifications. Unit-level modifications primarily employ turbine bypass heating, low-pressure cylinder zero-output heating, and high-back-pressure circulating water heating. These modifications increase the unit's heating capacity while reducing boiler output while meeting the heating load. However, these unit-level modifications have limited adaptability to the power system, and steam heat is lost during the heating process, limiting the system's peak-shaving flexibility. Summary of the Invention

[0004] The present invention provides a full-operating-condition coupled molten salt heat storage peak-shaving system for thermal power units and an operating method. By setting up a bypass molten salt heat storage and release system and flexibly switching the heat storage and release processes according to the characteristics of the external heat load and electric load, the unit's peak-shaving response speed is faster and the full-operating-condition peak-shaving flexibility is better.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A full-operation-condition coupled molten salt heat storage peak-shaving system for thermal power units, comprising a unit thermal system and a molten salt heat storage and release system;

[0007] The thermal system of the unit includes a boiler, a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder, a condenser, a low-temperature steam heater group, a deaerator, a high-temperature steam heater group and a generator; the high-pressure cylinder, the intermediate-pressure cylinder, the low-pressure cylinder and the generator are coaxially arranged for power generation; the boiler is connected with a main steam pipeline and a reheat hot section pipeline, the main steam pipeline is connected with the high-pressure cylinder inlet, the steam outlet of the high-pressure cylinder is divided into two paths, one path is connected with the high-temperature steam heater group, and the other path is connected with the boiler; the outlet of the reheat hot section pipeline is connected with the intermediate-pressure cylinder, and the outlet of the intermediate-pressure cylinder is divided into two paths, one path is connected with the low-pressure cylinder, and the other path is connected with the deaerator; the outlet of the low-pressure cylinder is divided into two paths, one path is connected with the low-temperature steam heater group, and the other path is connected with the condenser, the low-temperature steam heater group, the deaerator, the high-temperature steam heater group and the boiler in sequence;

[0008] The above-mentioned molten salt heat storage and release system includes a low-temperature molten salt tank, a medium-temperature molten salt tank, a high-temperature molten salt tank, a first high-temperature molten salt steam heat exchanger, a first medium-temperature molten salt steam heat exchanger, a second high-temperature molten salt steam heat exchanger, a second medium-temperature molten salt steam heat exchanger and an electric heater; the outlet of the above-mentioned low-temperature molten salt tank is divided into three paths, the first path is connected to the molten salt inlet of the above-mentioned first high-temperature molten salt steam heat exchanger, the molten salt outlet of the above-mentioned first high-temperature molten salt steam heat exchanger is connected to the inlet of the above-mentioned high-temperature molten salt tank, and the steam inlet of the above-mentioned first high-temperature molten salt steam heat exchanger is connected to the above-mentioned main steam pipeline, The steam outlet is connected to a first steam supply pipeline; the second road is connected to the molten salt inlet of the above-mentioned first medium-temperature molten salt steam heat exchanger, the molten salt outlet of the above-mentioned first medium-temperature molten salt steam heat exchanger is connected to the inlet of the above-mentioned medium-temperature molten salt tank, the steam inlet of the above-mentioned first medium-temperature molten salt steam heat exchanger is connected to the above-mentioned reheat hot section pipeline, and the steam outlet is connected to the second steam supply pipeline; the third road is connected to the molten salt inlet of the above-mentioned electric heater, and the molten salt outlet of the above-mentioned electric heater is respectively divided into two roads, one is connected to the inlet of the above-mentioned high-temperature molten salt tank, and the other is connected to the inlet of the above-mentioned medium-temperature molten salt tank;

[0009] The outlet of the above-mentioned high-temperature molten salt tank is connected with the molten salt inlet of the above-mentioned second high-temperature molten salt steam heat exchanger, the molten salt outlet of the above-mentioned second high-temperature molten salt steam heat exchanger is connected with the inlet of the above-mentioned low-temperature molten salt tank, the water inlet of the above-mentioned second high-temperature molten salt steam heat exchanger is connected with the first water supply pipeline, and the steam outlet is divided into two paths, one path is connected with the above-mentioned high-temperature steam heater group, and the other path is connected with the third steam supply pipeline; the outlet of the above-mentioned medium-temperature molten salt tank is connected with the molten salt inlet of the above-mentioned second medium-temperature molten salt steam heat exchanger, the molten salt outlet of the above-mentioned second medium-temperature molten salt steam heat exchanger is connected with the inlet of the above-mentioned low-temperature molten salt tank, the water inlet of the above-mentioned second medium-temperature molten salt steam heat exchanger is connected with the second water supply pipeline, the steam outlet is divided into two paths, one path is connected with the above-mentioned low-temperature steam heater group, and the other path is connected with the fourth steam supply pipeline.

[0010] Preferably, a low-pressure steam supply pipeline is connected between the above-mentioned medium-pressure cylinder outlet and the above-mentioned low-pressure cylinder outlet, the above-mentioned low-pressure steam supply pipeline is connected to the reheat steam inlet of the above-mentioned second high-temperature molten salt steam heat exchanger, and the reheat steam outlet is connected to the above-mentioned low-pressure cylinder inlet.

[0011] Preferably, the high-pressure cylinder outlet is connected to a re-cooling section pipeline, the re-cooling section pipeline is connected to the reheater in the boiler, and the steam inlet of the first high-temperature molten salt steam heat exchanger is connected to a return steam pipe.

[0012] Preferably, the steam return pipe is connected to a water supply pipe.

[0013] Preferably, a first high-temperature molten salt pump is provided between the low-temperature molten salt tank and the first high-temperature molten salt steam heat exchanger, and a second high-temperature molten salt pump is provided between the high-temperature molten salt tank and the second high-temperature molten salt steam heat exchanger;

[0014] A first medium-temperature molten salt pump is provided between the low-temperature molten salt tank and the first medium-temperature molten salt steam heat exchanger, and a second medium-temperature molten salt pump is provided between the medium-temperature molten salt tank and the second medium-temperature molten salt steam heat exchanger.

[0015] Preferably, the high-temperature steam heater group includes a plurality of high-temperature steam heaters connected in sequence, and the steam outlet of the second high-temperature molten salt steam heat exchanger is connected to the steam inlet of the high-temperature steam heater connected to the boiler.

[0016] Preferably, a bypass steam pipe is connected between the reheat hot section pipeline and the condenser inlet.

[0017] An operating method for a full-operation-condition coupled molten salt heat storage thermal power unit peak regulation system, comprising a heat storage stage and a heat release stage;

[0018] The heat storage stage occurs when the unit is reducing the power generation load, including: when the external heat load demand increases, the steam extracted from the main steam pipeline is increased to enter the first high-temperature molten salt steam heat exchanger, and the heat is exchanged with the low-temperature molten salt in the low-temperature molten salt tank. The molten salt after heat exchange enters the high-temperature molten salt tank for storage, and the steam after heat exchange enters the first steam supply pipeline. At the same time, the steam in the reheating hot section pipeline is increased to enter the first medium-temperature molten salt steam heat exchanger, and the heat is exchanged with the low-temperature molten salt in the low-temperature molten salt tank. The molten salt after heat exchange enters the medium-temperature molten salt tank for storage, and the steam after heat exchange enters the second supply Steam pipeline; when the external heat load demand decreases, the steam extraction of the main steam pipeline and the steam extraction of the reheating hot section pipeline are reduced. When the reduced power generation load demand of the unit cannot be met, the low-temperature molten salt in the low-temperature molten salt tank is heated by an electric heater to form medium-temperature molten salt and high-temperature molten salt, which are respectively stored in the medium-temperature molten salt tank and the high-temperature molten salt tank; when there is no external heat load demand, the steam extraction of the main steam pipeline and the steam extraction of the reheating hot section pipeline are stopped, and the low-temperature molten salt in the low-temperature molten salt tank is heated by an electric heater to form medium-temperature molten salt and high-temperature molten salt, which are respectively stored in the medium-temperature molten salt tank and the high-temperature molten salt tank;

[0019] The heat release stage occurs when the unit increases its power generation load, including: when the external heat load demand increases, the molten salt in the high-temperature molten salt tank exchanges heat with water through the second high-temperature molten salt steam heat exchanger, and the low-temperature molten salt after heat exchange enters the low-temperature molten salt tank, and the formed high-temperature steam is supplied to the outside through the third steam supply pipeline; at the same time, the molten salt in the medium-temperature molten salt tank exchanges heat with water through the second medium-temperature molten salt steam heat exchanger, and the low-temperature molten salt after heat exchange enters the low-temperature molten salt tank, and the formed medium-temperature steam is supplied to the outside through the fourth steam supply pipeline; when the external heat load demand decreases, the above-mentioned The high-temperature steam formed by the second high-temperature molten salt steam heat exchanger is divided into two paths, one path is supplied to the outside through the third steam supply pipeline, and the other path is supplied to the high-temperature steam heater group. At the same time, the medium-temperature steam formed by the above-mentioned second medium-temperature molten salt steam heat exchanger is divided into two paths, one path is supplied to the outside through the fourth steam supply pipeline, and the other path is supplied to the low-temperature steam heater group; when there is no heat load demand from the outside, the high-temperature steam formed by the above-mentioned second high-temperature molten salt steam heat exchanger is supplied to the high-temperature steam heater group, and at the same time, the medium-temperature steam formed by the second medium-temperature molten salt steam heat exchanger is supplied to the low-temperature steam heater group.

[0020] Preferably, the outlet of the high-pressure cylinder is connected to a re-cooling section pipeline, the re-cooling section pipeline is connected to the inlet of the reheater in the boiler, the steam inlet of the first high-temperature molten salt steam heat exchanger is connected to a return steam pipe, and the return steam pipe is connected to a water supply pipe; further comprising:

[0021] When the unit load is reduced and the steam in the re-cooling section pipeline cannot meet the minimum flow requirement, when the outside world needs heat load, the steam after heat exchange in the first high-temperature molten salt steam heat exchanger is divided into two paths, one enters the first steam supply pipeline, and the other enters the re-cooling section pipeline through the return steam pipe. At the same time, the water supply pipe replenishes water into the return steam pipe.

[0022] Preferably, a low-pressure steam supply pipeline is connected between the intermediate-pressure cylinder outlet and the low-pressure cylinder outlet, the low-pressure steam supply pipeline is connected to the low-pressure cylinder reheat steam inlet of the second high-temperature molten salt steam heat exchanger, and the low-pressure cylinder reheat steam outlet is connected to the low-pressure cylinder; further comprising:

[0023] When the unit increases its power generation load and there is no external heat load demand, the high-temperature steam generated by the second high-temperature molten salt steam heat exchanger is supplied to the high-temperature steam heater group, and the medium-temperature steam generated by the second medium-temperature molten salt steam heat exchanger is supplied to the low-temperature steam heater group; at the same time, the steam in the low-pressure steam supply pipeline passes through the second high-temperature molten salt steam heat exchanger to exchange heat with the high-temperature molten salt, and the steam after heat exchange enters the low-pressure cylinder to perform work.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The traditional technology extracts steam from the main steam pipeline and the reheat hot section pipeline and supplies steam to the outside by cooling and reducing the pressure through water spray. The present invention arranges a molten salt heat storage system in the high-pressure bypass. Three heat storage loops are formed in the system to recover the heat lost due to cooling and reducing the pressure, thereby improving energy utilization. In the process of reducing the power generation load of the unit, the operation of the three loops is controlled according to the external heat load demand, thereby completing the peak regulation of the process of reducing the power generation load of the unit; at the same time, three heat release loops are formed to release the heat stored in the molten salt. In the process of increasing the power generation load of the unit, the operation of the three loops is controlled according to the external heat load demand, thereby completing the peak regulation of the process of increasing the power generation load of the unit, thereby improving the peak regulation range and adjustment flexibility of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 Schematic diagram of the overall system of an embodiment of the present invention;

[0028] Figure 2 Schematic diagram of the heat storage stage system in an embodiment of the present invention (schematic diagram of system operation when the unit reduces power generation load and external heat load demand decreases);

[0029] Figure 3 This is a schematic diagram of system operation when the generator set in an embodiment of the present invention reduces power generation load and external heat load demand increases;

[0030] Figure 4 This is a schematic diagram of the system operation when the generator set in the embodiment of the present invention reduces the power generation load and there is no external load demand;

[0031] Figure 5 This is a schematic diagram of a heat release system according to an embodiment of the present invention;

[0032] Figure 6 This is a schematic diagram of system operation when the power generation load of the unit in the embodiment of the present invention is increased and the external heat load demand increases;

[0033] Figure 7 This is a schematic diagram of system operation when the power generation load of the unit in an embodiment of the present invention is increased and the external heat load demand is reduced;

[0034] Figure 8 This is a schematic diagram of system operation when the unit in an embodiment of the present invention increases the power generation load and there is no external heat load demand.

[0035] Description of reference numerals:

[0036] 1. Boiler; 2. High-pressure cylinder; 3. Medium-pressure cylinder; 4. Low-pressure cylinder; 5. Condenser; 6. Low-temperature steam heater group; 61. First low-temperature steam heater; 62. Second low-temperature steam heater; 63. Third low-temperature steam heater; 7. Deaerator; 8. High-temperature steam heater group; 81. First high-temperature steam heater; 82. Second high-temperature steam heater; 83. Third high-temperature steam heater; 9. Generator; 10. Main steam pipeline; 11. Reheating hot section pipeline; 12. Recooling cold section pipeline; 13. Low-temperature molten salt tank; 14. Medium-temperature molten salt tank; 15. High-temperature molten salt tank; 16. First high-temperature molten salt steam heat exchanger; 17. First pipe; 18. First high-temperature molten salt pump; 19. Second pipe; 20. Third pipe; 21. First steam supply pipeline; 22. First Medium-temperature molten salt steam heat exchanger; 23. Fourth pipe; 24. First medium-temperature molten salt pump; 25. Fifth pipe; 26. Sixth pipe; 27. Second steam supply pipeline; 28. Seventh pipe; 29. ​​Third molten salt pump; 30. Electric heater; 31. Eighth pipe; 32. Ninth pipe; 33. Second high-temperature molten salt steam heat exchanger; 34. Tenth pipe; 35. Second high-temperature molten salt pump; 36. First feed water pipeline; 37. First supplementary steam pipeline; 38. Third steam supply pipeline; 39. Second medium-temperature molten salt steam heat exchanger; 40. Eleventh pipe; 41. Second medium-temperature molten salt pump; 42. Second feed water pipeline; 43. Second supplementary steam pipeline; 44. Fourth steam supply pipeline; 45. Twelfth pipe; 46. Thirteenth pipe; 47. Return steam pipe; 48. Supplementary water pipe; 49. Bypass steam pipe. DETAILED DESCRIPTION

[0037] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0038] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0039] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0040] like Figure 1 As shown, an embodiment of the present invention provides a full-operating-condition coupled molten salt heat storage peak-shaving system for thermal power units, comprising a unit thermal system and a molten salt heat storage and release system, wherein the unit thermal system is used for power generation, and the molten salt heat storage and release system is used for storing heat wasted by the unit thermal system when the power generation load is reduced to supply heat, and at the same time, releases heat when the unit thermal system increases the power generation load and supplies heat to the outside world, thereby increasing the unit's heating capacity and power generation capacity.

[0041] Specifically, the thermal system of the unit includes a boiler 1, a high-pressure cylinder 2, an intermediate-pressure cylinder 3, a low-pressure cylinder 4, a condenser 5, a low-temperature steam heater group 6, a deaerator 7, a high-temperature steam heater group 8 and a generator 9; wherein the high-pressure cylinder 2, the intermediate-pressure cylinder 3, the low-pressure cylinder 4 and the generator 9 are coaxially arranged for power generation; the steam outlet of the boiler 1 is connected with a main steam pipeline 10, and the outlet of the reheater in the boiler 1 is connected with a reheat hot section pipeline 11, wherein the main steam pipeline 10 is connected with the inlet of the high-pressure cylinder 2 for supplying steam to the high-pressure cylinder 2, and the steam outlet of the high-pressure cylinder 2 is divided into two routes, one of which is connected with the high-temperature steam heater group 8 for providing the steam required for the high-temperature steam heater group 8 to heat the circulating water, and the other outlet is connected with a re-cooling section pipeline 12, and the re-cooling section pipeline 12 is connected with the inlet of the reheater in the boiler 1, so that the work done in the high-pressure cylinder 2 is completed. A portion of the steam returns to the reheater in the boiler 1 through the recooling cold section pipeline 12 for reheating; then the reheated steam re-enters the reheating hot section pipeline 11, and the outlet of the reheating hot section pipeline 11 is connected with the intermediate pressure cylinder 3, so that the reheated steam enters the intermediate pressure cylinder 3. After the steam is processed in the intermediate pressure cylinder 3, it is divided into two pipelines, one of which is connected with the low pressure cylinder 4, and the steam enters the low pressure cylinder 4 for further processing, and the other enters and is connected with the deaerator 7 to provide the heat required for the operation of the deaerator 7; the steam coming out of the low pressure cylinder 4 after processing is divided into two paths, one of which enters the low temperature steam heater group 6 to provide the heater therein with the steam required to heat the circulating water, and the other path is connected with the condenser 5, the low temperature steam heater group 6, the deaerator 7, the high temperature steam heater group 8 and the boiler 1 in sequence to form a circulating water subsystem to supply water to the boiler 1.

[0042] When the unit is under external heating load, steam is generally extracted from the reheat hot section pipeline 11 for external supply. However, the quality of the externally supplied steam is generally high, and it needs to be reduced in pressure and cooled. This part of the heat will be lost. Moreover, since steam is extracted from the reheat hot section pipeline 11, the amount of steam entering the intermediate pressure cylinder 3 will be reduced. In order to balance the output balance between the high-pressure cylinder 2 and the intermediate pressure cylinder 3, a part of the steam in the main steam pipeline 10 will be extracted for reduced pressure and cooling operations, and then returned to the furnace for heating, so that the amount of steam entering the high-pressure cylinder 2 is reduced, and the output balance between the high-pressure cylinder 2 and the intermediate pressure cylinder 3 is achieved. However, the heat of these two parts of cooling and pressure reduction will be lost. The molten salt heat storage and release system in this embodiment utilizes this part of heat, and uses this part of heat and combines it with the changes in the unit load and the changes in the external heat load demand to make real-time adjustments, thereby improving the system peak regulation range and adjustment flexibility.

[0043] Specifically, the molten salt heat storage and release system includes a low-temperature molten salt tank 13, a medium-temperature molten salt tank 14, a high-temperature molten salt tank 15, a first high-temperature molten salt steam heat exchanger 16, a first medium-temperature molten salt steam heat exchanger 22, a second high-temperature molten salt steam heat exchanger 33, a second medium-temperature molten salt steam heat exchanger 39 and an electric heater 30; the low-temperature molten salt tank 13 is used to store low-temperature molten salt, the medium-temperature molten salt tank 14 is used to store medium-temperature molten salt, and the high-temperature molten salt tank 15 is used to store high-temperature molten salt; through the unit thermal system and the low-temperature molten salt tank 13, the medium-temperature molten salt tank 14, the high-temperature molten salt tank 15, the first high-temperature molten salt steam heat exchanger 16, the first medium-temperature molten salt steam heat exchanger The mutual cooperation between the device 22 and the electric heater 30 realizes that when the load of the unit is reduced and heat is supplied to the outside, the heat generated by cooling and reducing pressure is stored through molten salt, thereby avoiding heat loss and realizing peak regulation when the unit reduces the power generation load; through the mutual cooperation between the unit thermal system and the low-temperature molten salt tank 13, the medium-temperature molten salt tank 14, the high-temperature molten salt tank 15, the second high-temperature molten salt steam heat exchanger 33, and the second medium-temperature molten salt steam heat exchanger 39, when the load of the unit increases and heat is supplied to the outside, the molten salt releases heat to supplement steam to the unit and supply heat to the outside, realizing peak regulation when the unit increases the power generation load, thereby improving the system peak regulation range and adjustment flexibility.

[0044] Specifically, the molten salt heat storage system has three heat storage circuits, circuit one: the outlet of the low-temperature molten salt tank 13 is connected to the molten salt inlet of the first high-temperature molten salt steam heat exchanger 16 by a first pipe 17, and the first pipe 17 is provided with a first high-temperature molten salt pump 18. The molten salt outlet of the first high-temperature molten salt steam heat exchanger 16 is connected to the inlet of the high-temperature molten salt tank 15 by a second pipe 19, the main steam pipeline 10 is connected to the steam inlet of the first high-temperature molten salt steam heat exchanger 16 by a third pipe 20, and the steam outlet of the first high-temperature molten salt steam heat exchanger 16 is connected to the first steam supply pipeline 21 for supplying steam to the outside; circuit two: the outlet of the low-temperature molten salt tank 13 is connected to the molten salt inlet of the first medium-temperature molten salt steam heat exchanger 22 by a fourth pipe 23, and the first pipe 17 is provided with a There is a first medium-temperature molten salt pump 24, the molten salt outlet of the first medium-temperature molten salt steam heat exchanger 22 is connected to the inlet of the medium-temperature molten salt tank 14 through a fifth pipe 25, the reheat hot section pipeline 11 is connected to the steam inlet of the first medium-temperature molten salt steam heat exchanger 22 through a sixth pipe 26, and the steam outlet of the first medium-temperature molten salt steam heat exchanger 22 is connected to the second steam supply pipeline 27 for supplying steam to the outside; loop three: the outlet of the low-temperature molten salt tank 13 is connected to the molten salt inlet of the electric heater 30 through a seventh pipe 28, and the third molten salt pump 29 is provided on the seventh pipe 28. The molten salt outlet of the electric heater 30 is respectively connected to the eighth pipe 31 and the ninth pipe 32, the eighth pipe 31 is connected to the inlet of the high-temperature molten salt tank 15, and the ninth pipe 32 is connected to the outlet of the medium-temperature molten salt tank 14.

[0045] Among them, loop one and loop two are used in the process of reducing the power generation load of the unit and supplying heat to the outside. Specifically, the low-temperature molten salt and the high-temperature steam in the main steam pipeline 10 are heat exchanged in the first high-temperature molten salt steam heat exchanger 16, and the low-temperature molten salt is converted into high-temperature molten salt and stored in the high-temperature molten salt tank 15. The steam after heat exchange is supplied to the outside through the first steam supply pipeline. At the same time, the low-temperature molten salt and the medium-temperature steam in the reheat hot section pipeline 11 are heat exchanged in the first medium-temperature molten salt steam heat exchanger 22, and the low-temperature molten salt is converted into medium-temperature molten salt and stored in the medium-temperature molten salt tank 14. The steam after heat exchange is supplied to the outside through the second steam supply pipeline; the above-mentioned loop one and loop two store the energy lost by cooling and reducing pressure through molten salt, and form high-temperature molten salt and medium-temperature molten salt through low-temperature molten salt respectively for storage, which can more fully recover the originally lost heat, and after heat exchange, two qualities of steam are formed and supplied to the outside, which can better meet the external steam demand. The electric heater 30 in loop three utilizes off-peak electricity, that is, electricity generated by the unit to reduce the power generation load. This electricity does not enter the grid and can be used directly by the electric heater 30. When there is little or no external heating demand, the corresponding steam extraction in the main steam pipeline 10 and the reheat hot section pipeline 11 will also be reduced. At this time, the electric heater 30 is needed to assist in peak regulation to reduce the power generation load. The electric heater 30 heats the low-temperature molten salt into medium-temperature molten salt and high-temperature molten salt respectively and stores them, converting the excess electrical energy into heat and storing it, indirectly helping the unit reduce the power generation load. Through the coordination and switching of the three loops, heat loss is avoided, and peak regulation is achieved when the unit reduces the power generation load.

[0046] Specifically, the molten salt heat storage system has three heat release circuits, circuit one: the outlet of the high-temperature molten salt tank 15 is connected to the molten salt inlet of the second high-temperature molten salt steam heat exchanger 33 by a tenth pipe 34, the tenth pipe 34 is provided with a second high-temperature molten salt pump 35, the molten salt outlet of the second high-temperature molten salt steam heat exchanger 33 is connected to the inlet of the low-temperature molten salt tank 13, the water inlet of the second high-temperature molten salt steam heat exchanger 33 is connected to the first water supply pipeline 36, the steam outlet is connected to the first steam supply pipeline 37 and the third steam supply pipeline 38, wherein the first steam supply pipeline 37 is connected to the high-temperature steam heater group 8 to supplement the steam required for heating the circulating water, and the third steam supply pipeline 38 is connected to the outside to supply steam to the outside; circuit two: the outlet of the medium-temperature molten salt tank 14 is connected to the molten salt inlet of the second medium-temperature molten salt steam heat exchanger 39 by an eleventh pipe 40, A second medium-temperature molten salt pump 41 is provided on the eleventh pipe 40, the molten salt outlet of the second medium-temperature molten salt steam heat exchanger 39 is connected to the inlet of the low-temperature molten salt tank 13, the water inlet of the second medium-temperature molten salt steam heat exchanger 39 is connected to the second water supply pipeline 42, and the steam outlet is connected to the second steam supplement pipeline 43 and the fourth steam supply pipeline 44, among which the second steam supplement pipeline 43 is connected to the low-temperature steam heater group 6 to supplement the steam required for heating the circulating water, and the third steam supply pipeline 38 is connected to the outside to supply steam to the outside; loop three: a low-pressure steam supply pipeline is connected between the outlet of the medium-pressure cylinder 3 and the outlet of the low-pressure cylinder 4, and the low-pressure steam supply pipeline is connected to the low-pressure cylinder reheat steam inlet of the second high-temperature molten salt steam heat exchanger 33 through the twelfth pipe 45, and the low-pressure cylinder reheat steam outlet is connected to the inlet of the low-pressure cylinder 4 through the thirteenth pipe 46 to reheat the steam entering the low-pressure cylinder 4.

[0047] Among them, loop one and loop two are used in the process of the unit increasing the power generation load and supplying heat to the outside. The water in the first water supply pipeline 36 and the high-temperature molten salt are heat exchanged in the second high-temperature molten salt steam heat exchanger 33. The low-temperature molten salt formed after the heat exchange enters the low-temperature molten salt tank 13 to form high-temperature steam, one path enters the high-temperature steam heater group 8 for steam supplement, and the other path is supplied to the outside through the third steam supply pipeline 38. At the same time, the water in the second water supply pipeline 42 and the medium-temperature molten salt are heat exchanged in the second medium-temperature molten salt steam heat exchanger 39. The low-temperature molten salt formed after the heat exchange enters the low-temperature molten salt tank 13 to form medium-temperature steam, one path enters the low-temperature steam heater group 6 for steam supplement, and the other path is supplied to the outside through the fourth steam supply pipeline 44. In this way, two qualities of steam can be formed in the molten salt heat release process to meet the steam demand of the outside world. Moreover, the above-mentioned steam is generated by heat exchange by utilizing the heat of the molten salt to satisfy the steam demand of the unit. While the thermal system is supplying steam, the heat load required by the outside world no longer needs to be supplied by extracting steam from the thermal system of the unit. Through these two aspects, the peak-shaving response speed of the unit when the power generation load is increased is faster; loop three is used when the unit is increasing the power generation load and there is no heat supply demand from the outside. A part of the steam entering the low-pressure cylinder 4 enters the second high-temperature molten salt steam heat exchanger 33 through the twelfth pipe 45, and exchanges heat with the high-temperature molten salt. The reheated steam formed after the heat exchange enters the low-pressure cylinder 4 again through the thirteenth pipe 46, thereby increasing the output of the low-pressure cylinder 4 and increasing the unit load. At the same time, the first steam supply pipeline 37 and the second steam supply pipeline 43 are still in operation, supplying steam to the high-temperature steam heater group 8 and the low-temperature steam heater group 6 respectively. The three cooperate to complete the regulation of the increased power generation load of the unit. By adding this loop, the peak-shaving response speed of the unit is made faster.

[0048] To sum up, the traditional technology extracts steam from the main steam pipeline 10 and the reheat hot section pipeline 11 and supplies steam to the outside by spraying water to reduce temperature and pressure. The present invention arranges a molten salt heat storage system in the high-pressure bypass, and three heat storage loops are formed in the system to recover the heat lost by cooling and reducing pressure, thereby improving energy utilization. In the process of reducing the power generation load of the unit, the operation of the three loops is controlled according to the external heat load demand, and the peak regulation of the process of reducing the power generation load of the unit is completed; at the same time, three heat release loops are formed to release the heat stored in the molten salt. In the process of increasing the power generation load of the unit, the operation of the three loops is controlled according to the external heat load demand, and the peak regulation of the process of increasing the power generation load of the unit is completed, thereby improving the peak regulation range and adjustment flexibility of the system.

[0049] Specifically, the high-temperature steam heater group 8 includes a plurality of high-temperature steam heaters connected in sequence, and the steam outlet of the second high-temperature molten salt steam heat exchanger 33 is connected to the steam inlet of the high-temperature steam heater connected to the boiler 1, so as to fully utilize the steam heat. In this embodiment, the high-temperature steam heater group 8 includes a first high-temperature steam heater 81, a second high-temperature steam heater 82, and a third high-temperature steam heater 83 in sequence, wherein the first high-temperature steam heater 81 is connected to the boiler 1, the third high-temperature steam heater 83 is connected to the water outlet of the deaerator 7, and one steam outlet of the high-pressure cylinder 2 is respectively connected to the steam inlet of the first high-temperature steam heater 81 and the second high-temperature steam heater 82, and the third high-temperature steam heater 83 is connected to the water outlet of the deaerator 7. 3 is connected to the steam outlet of the intermediate pressure cylinder 3, the low-temperature steam heater group 6 includes a first low-temperature steam heater 61, a second low-temperature steam heater 62, and a third low-temperature steam heater 63, wherein the first low-temperature steam heater 61 is connected to the deaerator 7, the third low-temperature steam heater 63 is connected to the condensate pump outlet, the condensate pump is connected to the condenser 5, one steam outlet of the intermediate pressure cylinder 3 is connected to the first low-temperature steam heater 61, the steam outlet of the low-pressure cylinder 4 is connected to the steam inlets of the second low-temperature steam heater 62 and the third low-temperature steam heater 63 respectively, and the outlet of the twelfth tube 45 can be connected to the steam inlet of the second low-temperature steam heater 62 or the third low-temperature steam heater 63.

[0050] Specifically, the re-cooling section pipeline 12 is connected to the inlet of the reheater in the boiler 1, and the steam inlet of the first high-temperature molten salt steam heat exchanger 16 is connected to the return steam pipe 47, and the return steam pipe 47 is connected to the water supply pipe 48. When the unit is deeply peak-shaving and the unit is in a lower load stage, that is, the unit is below 30% load, and the reflux steam in the re-cooling section pipeline 12 cannot meet the preset minimum flow requirement, a part of the steam after heat exchange from the first high-temperature molten salt steam heat exchanger 16 enters the re-cooling section pipeline 12 through the return steam pipe 47 for steam supply, and at the same time, the water supply pipe 48 supplies water to the return steam pipe 47 to meet the minimum flow requirement of the reflux steam in the re-cooling section pipeline 12, thereby avoiding pipeline burning.

[0051] In addition, a bypass steam pipe 49 is connected between the reheat hot section pipeline 11 and the inlet of the condenser 5. In order to prevent the intermediate pressure cylinder 3 from needing to be supplied with steam (for maintenance or startup reasons), the reheated steam is introduced into the condenser 5 through the bypass without passing through the intermediate pressure cylinder 3.

[0052] The present invention also discloses an operating method for a full-condition coupled molten salt heat storage thermal power unit peak regulation system, which includes a heat storage stage and a heat release stage. Three heat storage circuits are activated in the heat storage stage, and three heat release circuits are activated in the heat release stage.

[0053] Specifically, such as Figure 2As shown in Figure 2, the heat storage stage occurs when the unit is reducing the power generation load. The specific operating conditions include the following:

[0054] 1. When the external heat load demand increases, run heat storage loop 1 and loop 2 at the same time, such as Figure 3 As shown, a portion of the steam extracted from the main steam pipeline 10 is increased to enter the first high-temperature molten salt steam heat exchanger 16 from the third pipe 20, and heat exchange is performed with the low-temperature molten salt in the low-temperature molten salt tank 13. The molten salt after heat exchange enters the high-temperature molten salt tank 15 for storage, and the steam after heat exchange enters the first steam supply pipeline 21 to supply heat to the outside. At the same time, the steam in the reheat hot section pipeline 11 is increased to enter the first medium-temperature molten salt steam heat exchanger 22 through the sixth pipe 26 to exchange heat with the low-temperature molten salt in the low-temperature molten salt tank 13. The molten salt after heat exchange enters the medium-temperature molten salt tank 14 for storage, and the steam after heat exchange enters the second steam supply pipeline 27 to supply heat to the outside. In this operating condition, the heat lost by the high-temperature steam and the medium-temperature steam is respectively used to heat the low-temperature molten salt to high-temperature molten salt and medium-temperature molten salt for storage. The energy of the steam is utilized in a cascade manner, fully absorbed and stored, and finally two parameters of molten salt are formed for subsequent use, making peak regulation more flexible and forming two qualities of steam to meet the external steam demand first.

[0055] 2. When the external heat load demand decreases and cannot meet the reduced power generation load demand of the unit, the heat storage loop 1, loop 2 and loop 3 are operated at the same time, such as Figure 2 As shown, the steam extraction amount of the main steam pipeline 10 is reduced, and the steam enters the first high-temperature molten salt steam heat exchanger 16 from the third pipe 20, and exchanges heat with the low-temperature molten salt in the low-temperature molten salt tank 13. The molten salt after heat exchange enters the high-temperature molten salt tank 15 for storage, and the steam after heat exchange enters the first steam supply pipeline 21 and supplies heat to the outside. At the same time, the steam in the extraction reheating hot section pipeline 11 is increased and enters the first medium-temperature molten salt steam heat exchanger 22 through the sixth pipe 26, and exchanges heat with the low-temperature molten salt in the low-temperature molten salt tank 13. The molten salt after heat exchange enters the medium-temperature molten salt tank 14 Internal storage, the steam after heat exchange enters the second steam supply pipeline 27, and at the same time, off-peak electricity is used to make the electric heater 30 work, heating the low-temperature molten salt in the low-temperature molten salt tank 13 into medium-temperature molten salt and high-temperature molten salt, which enter the medium-temperature molten salt tank 14 and the high-temperature molten salt tank 15 for storage respectively; in this operating condition, the steam extraction amount of the main steam pipeline 10 and the reheat hot section pipeline 11 is reduced, which slows down the corresponding peak regulation speed of the unit, and the unit generates excess electricity, which is consumed by the electric heater 30 to generate electricity for the unit, and converted into heat stored in the molten salt, thereby storing more lost heat in disguise.

[0056] 3. When there is no external heat load demand, only loop 3 is operated, such as Figure 4As shown, the extraction of steam from the main steam pipeline 10 and the reheat hot section pipeline 11 is stopped, and the electric heater 30 is used to heat the low-temperature molten salt in the low-temperature molten salt tank 13 into medium-temperature molten salt and high-temperature molten salt, which are respectively stored in the medium-temperature molten salt tank 14 and the high-temperature molten salt tank 15; in this operating condition, the excess electricity generated by the unit is directly consumed by the electric heater 30 and converted into heat and stored in the molten salt, thereby storing more lost heat in disguise.

[0057] The heat release stage occurs when the unit increases the power generation load, such as Figure 5 The specific operating conditions include the following:

[0058] 1. When the external heat load demand increases, operate the inner sub-circuit of heat release circuit 1 and the inner sub-circuit of circuit 2, such as Figure 6 As shown, the molten salt in the high-temperature molten salt tank 15 enters the second high-temperature molten salt steam heat exchanger 33 through the tenth pipe 34 to exchange heat with water, and the low-temperature molten salt after heat exchange enters the low-temperature molten salt tank 13, and the formed high-temperature steam is supplied to the outside through the third steam supply pipeline 38. At the same time, the molten salt in the medium-temperature molten salt tank 14 exchanges heat with water through the second medium-temperature molten salt steam heat exchanger 39, and the low-temperature molten salt after heat exchange enters the low-temperature molten salt tank 13, and the formed medium-temperature steam is supplied to the outside through the fourth steam supply pipeline 44. In this operating condition, priority is given to meeting the heating demand of the outside world, so only the third steam supply pipeline 38 and the fourth steam supply pipeline 44 are operated to supply steam to the outside world, and there is no need to extract additional steam in the thermal system of the unit, which increases the output of the unit and increases the load of the unit.

[0059] 2. When the external heat load demand decreases, operate heat release loop 1 and loop 2, such as Figure 7 As shown, the molten salt in the high-temperature molten salt tank 15 enters the second high-temperature molten salt steam heat exchanger 33 through the tenth pipe 34 to exchange heat with water. The low-temperature molten salt after heat exchange enters the low-temperature molten salt tank 13. The high-temperature steam formed forms two paths: one path is supplied to the outside through the third steam supply line 38, and the other path is supplied to the first high-temperature steam heater 81 through the first supplementary steam line 37. At the same time, the molten salt in the medium-temperature molten salt tank 14 exchanges heat with water through the second medium-temperature molten salt steam heat exchanger 39. The low-temperature molten salt after heat exchange enters the low-temperature molten salt tank 13. The medium-temperature steam formed forms two paths: one path is supplied to the outside through the fourth steam supply line 44, and the other path is supplied to the third low-temperature steam heater 63 through the second supplementary steam line 43. In this operating condition, the external heating demand is reduced, and steam can be supplied to the unit thermal system, thereby reducing the steam extraction in the high-pressure cylinder 2, the intermediate-pressure cylinder 3, and the low-pressure cylinder 4, directly reducing the output of the high-pressure cylinder 2, the intermediate-pressure cylinder 3, and the low-pressure cylinder 4, and increasing the unit load.

[0060] 3. When the unit increases the power generation load and there is no external heat load demand, operate the inner part of the heat release circuit 1, the inner part of the circuit 2 and the circuit 3, such as Figure 8 As shown, the molten salt in the high-temperature molten salt tank 15 enters the second high-temperature molten salt steam heat exchanger 33 through the tenth pipe 34 to exchange heat with water. The low-temperature molten salt after heat exchange enters the low-temperature molten salt tank 13, and the high-temperature steam formed is supplied to the first high-temperature steam heater 81 through the first supplementary steam pipeline 37. The third steam supply pipe is closed. At the same time, the steam in the low-pressure steam supply pipeline passes through the second high-temperature molten salt steam heat exchanger 33 to exchange heat with the high-temperature molten salt. The steam after heat exchange enters the low-pressure cylinder 4 to perform work. At the same time, the molten salt in the medium-temperature molten salt tank 14 exchanges heat with water through the second medium-temperature molten salt steam heat exchanger 39. The low-temperature molten salt after heat exchange enters the low-temperature molten salt tank 13. The formed medium-temperature steam is supplied to the third low-temperature steam heater 63 through the second steam supply pipe 43, and the fourth steam supply pipe is closed. In this operating condition, since there is no external heat load demand, the steam coming out of the second high-temperature molten salt steam heat exchanger 33 and the second medium-temperature molten salt steam heat exchanger 39 all enters the unit's thermal system, thereby greatly reducing the steam extraction in the high-pressure cylinder 2, the intermediate-pressure cylinder 3 and the low-pressure cylinder 4, directly increasing the output of the high-pressure cylinder 2, the intermediate-pressure cylinder 3 and the low-pressure cylinder 4, and a part of the steam entering the low-pressure cylinder 4 is reheated and has higher quality. After entering the low-pressure cylinder 4, it can further increase the output of the low-pressure cylinder 4, directly increasing the unit load.

[0061] Moreover, in the stage of unit load reduction, if the unit is deeply peak-shaving, the unit is in a relatively low load stage, that is, the unit is below 30% load, and the reflux steam in the re-cooling section pipeline 12 cannot meet the preset minimum flow requirement, when the outside world needs heat load, the steam after heat exchange from the first high-temperature molten salt steam heat exchanger 16 will be divided into two paths, one path enters the first steam supply pipeline 21 to supply steam to the outside world, and the other part enters the re-cooling section pipeline 12 through the return steam pipe 47 for steam supplement. At the same time, the water supplement pipe 48 supplements water into the return steam pipe 47 to meet the minimum flow requirement of the reflux steam in the re-cooling section pipeline 12 to avoid pipeline burning.

[0062] The above-mentioned operation method has flexible heat storage and release processes. The heat storage and release processes can be flexibly switched according to the characteristics of the external heat load and electric load. The heat storage process utilizes the energy of steam in a cascade manner according to the external heat load demand. At the same time, when the external heat load is reduced or there is no external heat load, the heat storage peak regulation is completed with the assistance of electric heating. The heat release process can supply steam externally and make up steam for the unit according to the external heat load demand, quickly increase the unit load, and have a faster response speed, thereby having better peak regulation flexibility under all working conditions.

[0063] The above 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 replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. A full-operation-condition coupled molten salt heat storage thermal power unit peak regulation system, characterized in that: Including the unit thermal system and molten salt heat storage and release system; The thermal system of the unit includes a boiler, a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder, a condenser, a low-temperature steam heater group, a deaerator, a high-temperature steam heater group and a generator; the high-pressure cylinder, the intermediate-pressure cylinder, the low-pressure cylinder and the generator are coaxially arranged for power generation; the boiler is connected with a main steam pipeline and a reheat hot section pipeline, the main steam pipeline is connected with the high-pressure cylinder inlet, and the steam outlet of the high-pressure cylinder is divided into two paths, one path is connected with the high-temperature steam heater group, and the other path is connected with the boiler; the outlet of the reheat hot section pipeline is connected with the intermediate-pressure cylinder, and the intermediate-pressure cylinder outlet is divided into two paths, one path is connected with the low-pressure cylinder, and the other path is connected with the deaerator; the low-pressure cylinder outlet is divided into two paths, one path is connected with the low-temperature steam heater group, and the other path is connected with the condenser, the low-temperature steam heater group, the deaerator, the high-temperature steam heater group and the boiler in sequence; The molten salt heat storage and release system includes a low-temperature molten salt tank, a medium-temperature molten salt tank, a high-temperature molten salt tank, a first high-temperature molten salt steam heat exchanger, a first medium-temperature molten salt steam heat exchanger, a second high-temperature molten salt steam heat exchanger, a second medium-temperature molten salt steam heat exchanger and an electric heater; the outlet of the low-temperature molten salt tank is divided into three paths, the first path is connected to the molten salt inlet of the first high-temperature molten salt steam heat exchanger, the molten salt outlet of the first high-temperature molten salt steam heat exchanger is connected to the inlet of the high-temperature molten salt tank, and the steam inlet of the first high-temperature molten salt steam heat exchanger is connected to the main steam pipeline, The steam outlet is connected to a first steam supply pipeline; the second road is connected to the molten salt inlet of the first medium-temperature molten salt steam heat exchanger, the molten salt outlet of the first medium-temperature molten salt steam heat exchanger is connected to the inlet of the medium-temperature molten salt tank, the steam inlet of the first medium-temperature molten salt steam heat exchanger is connected to the reheat hot section pipeline, and the steam outlet is connected to the second steam supply pipeline; the third road is connected to the molten salt inlet of the electric heater, and the molten salt outlet of the electric heater is respectively two roads, one is connected to the inlet of the high-temperature molten salt tank, and the other is connected to the inlet of the medium-temperature molten salt tank; The outlet of the high-temperature molten salt tank is connected to the molten salt inlet of the second high-temperature molten salt steam heat exchanger, the molten salt outlet of the second high-temperature molten salt steam heat exchanger is connected to the inlet of the low-temperature molten salt tank, the water inlet of the second high-temperature molten salt steam heat exchanger is connected to the first water supply pipeline, and the steam outlet is divided into two paths, one path is connected to the high-temperature steam heater group, and the other path is connected to the third steam supply pipeline; the outlet of the medium-temperature molten salt tank is connected to the molten salt inlet of the second medium-temperature molten salt steam heat exchanger, the molten salt outlet of the second medium-temperature molten salt steam heat exchanger is connected to the inlet of the low-temperature molten salt tank, the water inlet of the second medium-temperature molten salt steam heat exchanger is connected to the second water supply pipeline, the steam outlet is divided into two paths, one path is connected to the low-temperature steam heater group, and the other path is connected to the fourth steam supply pipeline.

2. The full-operation-condition coupled molten salt heat storage thermal power generation unit peak-shaving system according to claim 1 is characterized in that: A low-pressure steam supply pipeline is connected between the intermediate-pressure cylinder outlet and the low-pressure cylinder outlet. The low-pressure steam supply pipeline is connected to the reheat steam inlet of the second high-temperature molten salt steam heat exchanger. The reheat steam outlet is connected to the low-pressure cylinder inlet.

3. The full-operation-condition coupled molten salt heat storage thermal power generation unit peak-shaving system according to claim 1 is characterized in that: The high-pressure cylinder outlet is connected to a re-cooling section pipeline, the re-cooling section pipeline is connected to the inlet of the reheater in the boiler, and the steam inlet of the first high-temperature molten salt steam heat exchanger is connected to a return steam pipe.

4. The full-operation-condition coupled molten salt heat storage thermal power generation unit peak-shaving system according to claim 3 is characterized in that: The steam return pipe is connected with a water supply pipe.

5. The full-operation-condition coupled molten salt heat storage thermal power generation unit peak-shaving system according to claim 1 is characterized in that: A first high-temperature molten salt pump is provided between the low-temperature molten salt tank and the first high-temperature molten salt steam heat exchanger, and a second high-temperature molten salt pump is provided between the high-temperature molten salt tank and the second high-temperature molten salt steam heat exchanger; A first medium-temperature molten salt pump is provided between the low-temperature molten salt tank and the first medium-temperature molten salt steam heat exchanger, and a second medium-temperature molten salt pump is provided between the medium-temperature molten salt tank and the second medium-temperature molten salt steam heat exchanger.

6. The full-operation-condition coupled molten salt heat storage thermal power generation unit peak-shaving system according to claim 1 is characterized in that: The high-temperature steam heater group includes a plurality of high-temperature steam heaters connected in sequence, and the steam outlet of the second high-temperature molten salt steam heat exchanger is connected to the steam inlet of the high-temperature steam heater connected to the boiler.

7. The full-operation-condition coupled molten salt heat storage thermal power generation unit peak-shaving system according to claim 1 is characterized in that: A bypass steam pipe is connected between the reheat hot section pipeline and the condenser inlet.

8. An operating method for a full-operation-condition coupled molten salt heat storage thermal power generation unit peak-shaving system according to any one of claims 1 to 7, characterized in that: It includes heat storage stage and heat release stage; The heat storage stage occurs when the unit is reducing the power generation load, including: when the external heat load demand increases, the steam extracted from the main steam pipeline is increased to enter the first high-temperature molten salt steam heat exchanger, and the heat is exchanged with the low-temperature molten salt in the low-temperature molten salt tank. The molten salt after heat exchange enters the high-temperature molten salt tank for storage, and the steam after heat exchange enters the first steam supply pipeline. At the same time, the steam in the reheating hot section pipeline is increased to enter the first medium-temperature molten salt steam heat exchanger, and the heat is exchanged with the low-temperature molten salt in the low-temperature molten salt tank. The molten salt after heat exchange enters the medium-temperature molten salt tank for storage, and the steam after heat exchange enters the second supply Steam pipeline; when the external heat load demand decreases, the steam extraction of the main steam pipeline and the steam extraction of the reheating hot section pipeline are reduced. When the reduced power generation load demand of the unit cannot be met, the low-temperature molten salt in the low-temperature molten salt tank is heated by an electric heater to form medium-temperature molten salt and high-temperature molten salt, which are respectively stored in the medium-temperature molten salt tank and the high-temperature molten salt tank; when there is no external heat load demand, the steam extraction of the main steam pipeline and the steam extraction of the reheating hot section pipeline are stopped, and the low-temperature molten salt in the low-temperature molten salt tank is heated by an electric heater to form medium-temperature molten salt and high-temperature molten salt, which are respectively stored in the medium-temperature molten salt tank and the high-temperature molten salt tank; The heat release stage occurs when the unit increases its power generation load, including: when the external heat load demand increases, the molten salt in the high-temperature molten salt tank exchanges heat with water through the second high-temperature molten salt steam heat exchanger, and the low-temperature molten salt after heat exchange enters the low-temperature molten salt tank, and the formed high-temperature steam is supplied to the outside through the third steam supply pipeline; at the same time, the molten salt in the medium-temperature molten salt tank exchanges heat with water through the second medium-temperature molten salt steam heat exchanger, and the low-temperature molten salt after heat exchange enters the low-temperature molten salt tank, and the formed medium-temperature steam is supplied to the outside through the fourth steam supply pipeline; when the external heat load demand decreases, the above-mentioned The high-temperature steam formed by the second high-temperature molten salt steam heat exchanger is divided into two paths, one path is supplied to the outside through the third steam supply pipeline, and the other path is supplied to the high-temperature steam heater group. At the same time, the medium-temperature steam formed by the above-mentioned second medium-temperature molten salt steam heat exchanger is divided into two paths, one path is supplied to the outside through the fourth steam supply pipeline, and the other path is supplied to the low-temperature steam heater group; when there is no heat load demand from the outside, the high-temperature steam formed by the above-mentioned second high-temperature molten salt steam heat exchanger is supplied to the high-temperature steam heater group, and at the same time, the medium-temperature steam formed by the second medium-temperature molten salt steam heat exchanger is supplied to the low-temperature steam heater group.

9. The method for operating the full-operation-condition coupled molten salt heat storage thermal power generation unit peak-shaving system according to claim 8, characterized in that: The high-pressure cylinder outlet is connected to a re-cooling section pipeline, the re-cooling section pipeline is connected to the reheater inlet of the boiler, the steam inlet of the first high-temperature molten salt steam heat exchanger is connected to a return steam pipe, and the return steam pipe is connected to a water supply pipe; further comprising: When the unit load is reduced and the steam in the re-cooling section pipeline cannot meet the minimum flow requirement, when the outside world needs heat load, the steam after heat exchange in the first high-temperature molten salt steam heat exchanger is divided into two paths, one enters the first steam supply pipeline, and the other enters the re-cooling section pipeline through the return steam pipe. At the same time, the water supply pipe replenishes water into the return steam pipe.

10. The method for operating the full-operation-condition coupled molten salt heat storage thermal power generation unit peak-shaving system according to claim 8, characterized in that: A low-pressure steam supply pipeline is connected between the outlet of the intermediate-pressure cylinder and the outlet of the low-pressure cylinder, the low-pressure steam supply pipeline is connected to the low-pressure cylinder reheat steam inlet of the second high-temperature molten salt steam heat exchanger, and the low-pressure cylinder reheat steam outlet is connected to the low-pressure cylinder; further comprising: When the unit increases its power generation load and there is no external heat load demand, the high-temperature steam generated by the second high-temperature molten salt steam heat exchanger is supplied to the high-temperature steam heater group, and the medium-temperature steam generated by the second medium-temperature molten salt steam heat exchanger is supplied to the low-temperature steam heater group; at the same time, the steam in the low-pressure steam supply pipeline passes through the second high-temperature molten salt steam heat exchanger to exchange heat with the high-temperature molten salt, and the steam after heat exchange enters the low-pressure cylinder to perform work.

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