High-temperature steam thermal energy cascade utilization external steam supply system and method

Abstract

The application relates to the technical field of power generation, in particular to a high-temperature steam heat energy cascade utilization external steam supply system and method. The high-temperature steam heat energy cascade utilization external steam supply system comprises at least one heat storage unit, a first pipeline, a first heat exchange assembly arranged between the first pipeline and the at least one heat storage unit and used for exchanging heat between high-temperature steam in the first pipeline and medium in the at least one heat storage unit, a second pipeline, a second heat exchange assembly arranged between the second pipeline and the at least one heat storage unit and used for exchanging heat between water / low-temperature steam in the second pipeline and the medium in the at least one heat storage unit, and the second pipeline is connected to a steam supply main pipe; the at least one heat storage unit comprises an electric heater used for heating the medium in the at least one heat storage unit; and the first pipeline is provided with a first branch pipe connected to the steam supply main pipe. According to the above scheme, the number of times of changing loads during unit operation can be reduced, and the safety of unit operation can be improved.

Description

Technical Field

[0001] This application relates to the field of power generation technology, and more specifically, to a system and method for the cascade utilization of high-temperature steam thermal energy for external steam supply. Background Technology

[0002] Currently, thermal power units are the main participants in peak power regulation. However, thermal power units that participate in external heating have poor heating regulation capabilities when dealing with the cyclical fluctuations in the heating demand of heat users (such as different heating demands between day and night, and frequent fluctuations in industrial steam demand of enterprise users at different times), which often results in the waste of heat.

[0003] This invention addresses the problem of thermal power unit heating load being closely coupled with the unit body and frequent load changes. It makes full use of steam molten salt heat storage and release system, molten salt electric heat storage system, hot water storage tank, and electrode steam boiler to achieve cascade utilization of external steam heat, effective recovery and utilization of heating margin, reduce the number of load changes during unit operation, and improve unit operation safety. Summary of the Invention

[0004] This application provides at least one high-temperature steam thermal energy cascade utilization external steam supply system and method, which can reduce the number of unit operation load changes and improve unit operation safety.

[0005] In a first aspect, embodiments of this application provide a high-temperature steam thermal energy cascade utilization and external steam supply system, comprising:

[0006] At least one thermal storage unit;

[0007] A first pipeline is provided between the first pipeline and the at least one thermal storage unit, and the first heat exchange component is used to exchange heat between the high-temperature steam in the first pipeline and the medium in the at least one thermal storage unit.

[0008] A second pipeline is provided between the second pipeline and the at least one thermal storage unit, and a second heat exchange component is provided between the second pipeline and the at least one thermal storage unit. The second heat exchange component is used to exchange heat between the water / low-temperature steam in the second pipeline and the medium in the at least one thermal storage unit. The second pipeline is connected to the steam supply header.

[0009] Wherein, the at least one thermal storage unit includes an electric heater, which is used to heat the medium in the at least one thermal storage unit;

[0010] The first pipeline is provided with a first branch, which is connected to the steam supply main pipeline.

[0011] According to the above scheme, the system can supply steam to the user end through branch lines of the first pipeline. This configuration allows for the simultaneous supply of steam and the storage (segmented) heat of the high-temperature steam in the thermal storage unit. Furthermore, the system can use the medium in the thermal storage unit to heat water / low-temperature steam in the second pipeline to generate the steam required by the user. Since the medium in the thermal storage unit can be heated by high-temperature steam or an electric heater, the system can use an electric heater to compensate for insufficient heat storage in the thermal storage unit, thus reducing the number of load changes during unit operation and improving unit operational safety.

[0012] In one optional implementation, the at least one thermal storage unit includes a first thermal storage unit, a second thermal storage unit, and a third thermal storage unit.

[0013] In one optional embodiment, the first heat exchange assembly includes a first heat exchanger, a third heat exchanger, and a fifth heat exchanger. The first heat exchanger is disposed between the first pipeline and the first heat storage unit, the third heat exchanger is disposed between the first pipeline and the second heat storage unit, and the fifth heat exchanger is disposed between the first pipeline and the third heat storage unit.

[0014] The second heat exchange assembly includes a second heat exchanger, a fourth heat exchanger, and a sixth heat exchanger. The second heat exchanger is disposed between the second pipeline and the first heat storage unit, the fourth heat exchanger is disposed between the second pipeline and the second heat storage unit, and the sixth heat exchanger is disposed between the second pipeline and the third heat storage unit.

[0015] In one optional embodiment, the first thermal storage unit includes a first circulation pipeline, a first low-temperature salt tank, and a first high-temperature salt tank, wherein the first low-temperature salt tank and the first high-temperature salt tank are connected in series on the first circulation pipeline.

[0016] The electric heater is installed on the first circulation pipeline and is used to heat the molten salt output from the first low-temperature salt tank.

[0017] In one alternative embodiment, the first heat exchanger is disposed on the first circulation pipeline and located between the salt outlet of the first low-temperature salt tank and the salt inlet of the first high-temperature salt tank.

[0018] The first circulation pipeline is provided with a medium bypass, and the two ends of the medium bypass are respectively connected to the two ends of the first heat exchanger.

[0019] In one optional embodiment, the second pipeline is provided with a first bypass and a second bypass, the two ends of the first bypass being connected to the two ends of the fourth heat exchanger, and the two ends of the second bypass being connected to the two ends of the sixth heat exchanger.

[0020] In one optional embodiment, the second pipeline is provided with a second branch and a seventh heat exchanger. The steam inlet of the second branch is connected to the steam outlet of the second heat exchanger. The seventh heat exchanger is disposed between the second branch and the second pipeline and is used to exchange heat between the medium in the second branch and the medium in the second pipeline.

[0021] In one alternative embodiment, the second pipeline is provided with a third bypass, the two ends of which are respectively connected to the two ends of the seventh heat exchanger.

[0022] In one optional embodiment, the second pipeline is provided with a third branch and a deoxygenation device, wherein the steam inlet of the third branch is connected to the steam outlet of the second heat exchanger, and the steam outlet of the third branch is connected to the steam inlet of the deoxygenation device.

[0023] Secondly, embodiments of this application also provide a method for external steam supply through the cascade utilization of high-temperature steam thermal energy, applicable to the external steam supply system for the cascade utilization of high-temperature steam thermal energy as described in any of the first aspects, the method comprising: a thermal storage operation mode, a thermal release operation mode, and a direct heating operation mode;

[0024] In the thermal storage operation mode, the second pipeline is closed, and the first pipeline and the first branch are opened, so that the first branch diverts the high-temperature steam in the first pipeline to supply steam to the steam supply main pipeline.

[0025] In the heat release operation mode, the first branch is closed and the second pipeline is opened. The water / low-temperature steam in the second pipeline is heat-exchanged with the medium in the at least one heat storage unit through the second heat exchange component to form high-temperature steam and supply steam to the steam supply header.

[0026] In the direct heating operation mode, the first branch is closed, the second pipeline and the electric heater are turned on, the medium in the at least one heat storage unit is heated by the electric heater, and the water / low-temperature steam in the second pipeline is exchanged with the medium in the at least one heat storage unit by the second heat exchange component to form high-temperature steam and supply steam to the steam supply header.

[0027] According to the above scheme, the system can supply steam to the user end through branch lines of the first pipeline. This configuration allows for the simultaneous supply of steam and the storage (segmented) heat of the high-temperature steam in the thermal storage unit. Furthermore, the system can use the medium in the thermal storage unit to heat water / low-temperature steam in the second pipeline to generate the steam required by the user. Since the medium in the thermal storage unit can be heated by high-temperature steam or an electric heater, the system can use an electric heater to compensate for insufficient heat storage in the thermal storage unit, thus reducing the number of load changes during unit operation and improving unit operational safety.

[0028] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. These drawings are incorporated in and constitute a part of this specification. They illustrate embodiments conforming to this application and, together with the specification, serve to explain the technical solutions of this application. It should be understood that the following drawings only show some embodiments of this application and should not be considered as limiting the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This paper shows a schematic diagram of a high-temperature steam thermal energy cascade utilization external steam supply system provided in an embodiment of this application;

[0031] Figure 2 A schematic diagram of the thermal storage operation mode provided in the embodiments of this application is shown;

[0032] Figure 3 A schematic diagram of the heat release operation mode provided in the embodiments of this application is shown;

[0033] Figure 4 A schematic diagram of the direct heating operation mode provided in the embodiments of this application is shown;

[0034] Figure label:

[0035] 10. First pipeline; 11. First branch pipeline;

[0036] 20. Second pipeline; 21. First bypass; 22. Second bypass; 23. Second branch; 24. Third bypass; 25. First deaerator; 26. Second deaerator; 27. Third branch; 28. Steam unit;

[0037] 31. First circulation pipeline; 32. First low-temperature brine tank; 33. First high-temperature brine tank; 34. Medium bypass; 35. Electric heater;

[0038] 41. Second circulation pipeline; 42. Second low-temperature brine tank; 43. Second high-temperature brine tank;

[0039] 51. Third circulation pipeline; 52. Fourth circulation pipeline; 53. Hot water storage tank;

[0040] 61. First heat exchanger; 62. Third heat exchanger; 63. Fifth heat exchanger;

[0041] 71. Second heat exchanger; 72. Fourth heat exchanger; 73. Sixth heat exchanger;

[0042] 81. The seventh heat exchanger. Detailed Implementation

[0043] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0044] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0045] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0046] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0047] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0048] refer to Figure 1 The high-temperature steam thermal energy cascade utilization external steam supply system provided in this application embodiment includes:

[0049] At least one thermal storage unit.

[0050] A first pipeline 10 is provided between the first pipeline 10 and at least one thermal storage unit, and a first heat exchange component is provided between the first pipeline 10 and at least one thermal storage unit. The first heat exchange component is used to exchange heat between the high-temperature steam in the first pipeline 10 and the medium in the at least one thermal storage unit.

[0051] A second heat exchange assembly is provided between the second pipeline 20 and at least one thermal storage unit. The second heat exchange assembly is used to exchange heat between the water / low-temperature steam in the second pipeline 20 and the medium in at least one thermal storage unit. The second pipeline 20 is connected to the steam supply header.

[0052] At least one heat storage unit includes an electric heater 35 for heating the medium in the at least one heat storage unit. The first pipeline 10 is provided with a first branch 11, which is connected to the steam supply main pipe. Specifically, the steam inlet of the first branch 11 is connected to the portion of the first pipeline 10 located between the first heat exchanger 61 and the third heat exchanger 62, and the steam outlet of the first branch 11 is connected to the steam supply main pipe.

[0053] The high-temperature steam thermal energy cascade utilization external steam supply system provided in this application embodiment can supply steam in different operating modes according to different usage scenarios.

[0054] When the heating demand from external heat users is significantly low, the system can activate the thermal storage operation mode. The specific operating piping (solid lines) and components for this mode are as follows: Figure 2 As shown. Specifically, in the thermal storage operation mode, the second pipeline 20 is closed, and the first pipeline 10 and the first branch 11 are opened, so that the high-temperature steam in the first pipeline 10 is diverted to the steam supply main pipeline by the first branch 11.

[0055] When heating demand surges and the original unit's heating capacity is insufficient, the system can activate the heat release operation mode. The specific operating pipelines (solid lines) and components for this mode are as follows: Figure 3 As shown. Specifically, in the heat release operation mode, the first branch 11 is closed and the second pipeline 20 is opened. The water / low-temperature steam in the second pipeline 20 exchanges heat with the medium in at least one heat storage unit through the second heat exchange component to form high-temperature steam and supply steam to the steam supply header.

[0056] In extreme cases where the unit's thermal storage is completely depleted and cannot meet the unit's external heating needs, to ensure the stability of the system's external heating supply, the system can activate a direct heating operation mode. This mode relies solely on electricity and existing system equipment to achieve continuous and stable external heating. The specific operating pipelines (solid lines) and components for this mode are as follows: Figure 4 As shown. Specifically, in the direct heating operation mode, the first branch 11 is closed, and the second pipeline 20, electric heater 35 (and steam device 28) are opened. The medium in at least one heat storage unit is heated by the electric heater 35, and the water / low-temperature steam in the second pipeline 20 is exchanged with the medium in at least one heat storage unit by the second heat exchange component to form high-temperature steam and supply steam to the steam supply header.

[0057] According to the above scheme, the system can supply steam to the user end through a branch of the first pipeline 10. This configuration allows for the simultaneous supply of steam and the storage (segmented) of the heat from the high-temperature steam in the thermal storage unit. Furthermore, the system can use the medium in the thermal storage unit to heat the water / low-temperature steam in the second pipeline 20 to generate the steam required by the user. Since the medium in the thermal storage unit can be heated by high-temperature steam or by the electric heater 35, the system can use the electric heater 35 to compensate for insufficient heat storage in the thermal storage unit, thus reducing the number of load changes during unit operation and improving unit operational safety.

[0058] In some embodiments, the thermal storage unit includes a first thermal storage unit, a second thermal storage unit, and a third thermal storage unit.

[0059] A first heat exchanger 61 is provided between the first thermal storage unit and the first pipeline 10. The first heat exchanger 61 is used to exchange heat between the high-temperature steam in the first pipeline 10 and the medium in the first thermal storage unit, so as to store part of the heat of the high-temperature steam in the first thermal storage unit. A second heat exchanger 71 is provided between the first thermal storage unit and the second pipeline 20. The second heat exchanger 71 is used to exchange heat between the water / low-temperature steam in the second pipeline 20 and the medium in the first thermal storage unit, so as to heat the water / low-temperature steam.

[0060] In a specific configuration, the first heat storage unit can employ a high-temperature molten salt device, which may include a first circulation pipeline 31, a first low-temperature salt tank 32, and a first high-temperature salt tank 33. The first low-temperature salt tank 32 and the first high-temperature salt tank 33 are connected in series on the first circulation pipeline 31. Specifically, a first heat exchanger 61 is installed on the first circulation pipeline 31, located between the salt outlet of the first low-temperature salt tank 32 and the salt inlet of the first high-temperature salt tank 33. When the molten salt output from the first low-temperature salt tank 32 undergoes heat exchange through the first heat exchanger 61, it is stored in the first high-temperature salt tank 33, thus achieving heat storage. A second heat exchanger 71 is installed on the first circulation pipeline 31, located between the salt inlet of the first low-temperature salt tank 32 and the salt outlet of the first high-temperature salt tank 33. When the molten salt output from the first high-temperature salt tank 33 undergoes heat exchange through the second heat exchanger 71, it is stored in the first low-temperature salt tank 32, thus achieving heat release.

[0061] A third heat exchanger 62 is provided between the second thermal storage unit and the first pipeline 10. The third heat exchanger 62 is used to exchange heat between the high-temperature steam in the first pipeline 10 and the medium in the second thermal storage unit, so as to store part of the heat of the high-temperature steam in the second thermal storage unit. A fourth heat exchanger 72 is provided between the second thermal storage unit and the second pipeline 20. The fourth heat exchanger 72 is used to exchange heat between the water / low-temperature steam in the second pipeline 20 and the medium in the second thermal storage unit, so as to heat the water / low-temperature steam.

[0062] In a specific configuration, the second heat storage unit can employ a cryogenic molten salt device. This device includes a second circulation pipeline 41, a second cryogenic salt tank 42, and a second high-temperature salt tank 43, which are connected in series on the second circulation pipeline 41. Specifically, a third heat exchanger 62 is installed on the second circulation pipeline 41, located between the outlet of the second cryogenic salt tank 42 and the inlet of the second high-temperature salt tank 43. Molten salt output from the second cryogenic salt tank 42 is stored in the second high-temperature salt tank 43 after heat exchange with the third heat exchanger 62, thus achieving heat storage. A fourth heat exchanger 72 is installed on the second circulation pipeline 41, located between the inlet of the second cryogenic salt tank 42 and the outlet of the second high-temperature salt tank 43. Molten salt output from the second high-temperature salt tank 43 is stored in the second cryogenic salt tank 42 after heat exchange with the fourth heat exchanger 72, thus achieving heat release.

[0063] A fifth heat exchanger 63 is provided between the third thermal storage unit and the first pipeline 10. The fifth heat exchanger 63 is used to exchange heat between the high-temperature steam in the first pipeline 10 and the medium in the third thermal storage unit, so as to store part of the heat of the high-temperature steam in the third thermal storage unit. A sixth heat exchanger 73 is provided between the third thermal storage unit and the second pipeline 20. The sixth heat exchanger 73 is used to exchange heat between the water / low-temperature steam in the second pipeline 20 and the medium in the third thermal storage unit, so as to heat the water / low-temperature steam.

[0064] In a specific configuration, the third heat storage unit can be a water-based heat storage device. This device may include a third circulation pipe 51, a fourth circulation pipe 52, and a hot water storage tank 53. The hot water storage tank 53 has a first inlet, a second inlet, a first outlet, and a second outlet. The two ends of the third circulation pipe 51 are connected to the first inlet and the first outlet, respectively, and the two ends of the fourth circulation pipe 52 are connected to the second inlet and the second outlet, respectively. In a specific configuration, a fifth heat exchanger 63 is installed on the third circulation pipe 51. When the water tank and the third circulation pipe 51 form a water circulation, the water passing through the fifth heat exchanger 63 exchanges heat with high-temperature steam and then returns to the water tank, thus storing heat. A sixth heat exchanger 73 is installed on the fourth circulation pipe 52. When the water tank and the fourth circulation pipe 52 form a water circulation, the water passing through the sixth heat exchanger 73 exchanges heat with water / low-temperature steam and then returns to the water tank, thus releasing heat.

[0065] In practical applications, high-temperature steam can sequentially pass through the first heat exchanger 61 and the third heat exchanger 62 to become saturated water. The saturated water then passes through the fifth heat exchanger 63 to become subcooled water, thus storing the heat of the high-temperature working fluid in the first, second, and third heat storage units. Water / low-temperature steam can sequentially pass through the sixth heat exchanger 73, the fourth heat exchanger 72, and the second heat exchanger 71, and sequentially obtain heat from the third, second, and first heat storage units to obtain the steam required by the user.

[0066] It should be noted that, in order to achieve water circulation, water pumps can be installed in the third circulation pipe 51, the fourth circulation pipe 52, and the second pipe 20 respectively.

[0067] In some embodiments, an electric heater 35 is disposed in the first heat storage unit, specifically for heating the medium in the first heat storage unit. Specifically, the electric heater 35 is disposed on the first circulation pipeline 31 for heating the molten salt output from the first low-temperature salt tank 32.

[0068] Furthermore, the first circulation pipeline 31 is equipped with a medium bypass 34, with its two ends connected to the two ends of the first heat exchanger 61, respectively. In practical use, the molten salt output from the first low-temperature salt tank 32 can enter the first high-temperature salt tank 33 via the first heat exchanger 61, or it can enter the first high-temperature salt tank 33 via the medium bypass 34. This arrangement allows the molten salt to operate in direct heating mode without passing through the first heat exchanger 61, which helps reduce heat loss.

[0069] In some embodiments, the second pipeline 20 is provided with a steam device 28 for converting water in the second pipeline 20 into saturated steam.

[0070] In a specific configuration, the steam device 28 is specifically located in the section of the second pipeline 20 between the second heat exchanger 71 and the fourth heat exchanger 72.

[0071] In some embodiments, the second pipeline 20 is provided with a first bypass 21, the two ends of which are respectively connected to the two ends of the fourth heat exchanger 72. In actual use, the water / low-temperature steam in the second pipeline 20 can flow to the second heat exchanger 71 through the fourth heat exchanger 72, or it can flow to the second heat exchanger 71 through the first bypass 21. This arrangement allows the water / low-temperature steam to operate without passing through the fourth heat exchanger 72 in direct heating mode, which helps to reduce heat loss.

[0072] In some embodiments, the second pipeline 20 is provided with a second bypass 22, the two ends of which are respectively connected to the two ends of the sixth heat exchanger 73. In actual use, the water / low-temperature steam in the second pipeline 20 can flow to the fourth heat exchanger 72 through the sixth heat exchanger 73, or it can flow to the fourth heat exchanger 72 through the second bypass 22. This arrangement allows the water / low-temperature steam to operate without passing through the sixth heat exchanger 73 in direct heating mode, which helps to reduce heat loss.

[0073] In some embodiments, the second pipeline 20 is provided with a second branch 23 and a seventh heat exchanger 81. The steam inlet of the second branch 23 is connected to the steam outlet of the second heat exchanger 71, and the seventh heat exchanger 81 is disposed between the second branch 23 and the second pipeline 20. The seventh heat exchanger 81 is used to exchange heat between the medium in the second branch 23 and the medium in the second pipeline 20. This configuration enables preheating of water / low-temperature steam in direct heating operation mode, which helps to reduce the power consumption of the steam unit 28.

[0074] Yes, the second pipeline 20 splits into two branches after passing through the second heat exchanger 71. The first branch is connected to the steam supply main pipe, and the second branch flows to the seventh heat exchanger 81. That is, the second branch can be used as the second branch 23 of the second pipeline 20.

[0075] Alternatively, the second pipeline 20 splits into two branches before passing through the second heat exchanger 71. The first branch, after heat exchange in the second heat exchanger 71, supplies steam to the main steam supply pipe. The second branch, after heat exchange in the second heat exchanger 71, flows to the seventh heat exchanger 81. This second branch can serve as the second branch 23 of the second pipeline 20. Figures 1-4 As shown.

[0076] In some embodiments, the second pipe 20 is provided with a third bypass 24, the two ends of which are respectively connected to the two ends of the seventh heat exchanger 81. In actual use, water in the second pipe 20 can flow to the second heat exchanger 71 through the seventh heat exchanger 81, or it can flow to the second heat exchanger 71 through the third bypass 24. This arrangement allows water to bypass the seventh heat exchanger 81 during heat release operation, which helps to reduce heat loss.

[0077] In some embodiments, the second pipeline 20 is provided with a deoxygenation device for deoxygenating the water in the second pipeline 20.

[0078] In a specific configuration, the deaerator can be connected to the steam outlet of the second branch 23, so that the steam can flow into the deaerator after heat exchange in the seventh heat exchanger 81. This helps to increase the water temperature, thereby facilitating the removal of oxygen from the water. It should be noted that increasing the water temperature can accelerate the reaction rate between oxygen and water, thus enabling faster removal of oxygen from the water vapor.

[0079] Furthermore, the deoxygenation device may include a first deoxygenation device 25 and a second deoxygenation device 26, which are connected in parallel. In the heat release operation mode, the second pipeline 20 can be deoxygenated through the first deoxygenation device 25; in the direct heating operation mode, the second pipeline 20 can be deoxygenated through the first deoxygenation device 25.

[0080] In some embodiments, the second pipeline 20 is provided with a third branch 27, the steam inlet of the third branch 27 being connected to the steam outlet of the second heat exchanger 71, and the steam outlet of the third branch 27 being connected to the steam inlet of the deaerator. This configuration can further increase the water temperature and achieve thermal deaeration of the feed water.

[0081] This application also provides a method for external steam supply through the cascade utilization of high-temperature steam thermal energy, applicable to the aforementioned high-temperature steam thermal energy cascade utilization and external steam supply system.

[0082] The high-temperature steam thermal energy cascade utilization method for external steam supply includes: thermal storage operation mode, thermal release operation mode, and direct heating operation mode.

[0083] In the thermal storage operation mode, the second pipeline 20 is closed, and the first pipeline 10 and the first branch 11 are opened, so that the high-temperature steam in the first pipeline 10 is diverted to the steam supply main pipeline via the first branch 11.

[0084] In the heat release operation mode, the first branch 11 is closed and the second pipeline 20 is opened. The water / low-temperature steam in the second pipeline 20 is heat-exchanged with the medium in at least one heat storage unit through the second heat exchange component to form high-temperature steam and supply steam to the steam supply header.

[0085] In direct heating operation mode, the first branch 11 is closed, the second pipeline 20 and the electric heater 35 are opened, the medium in at least one heat storage unit is heated by the electric heater 35, and the water / low-temperature steam in the second pipeline 20 is exchanged with the medium in at least one heat storage unit by the second heat exchange component to form high-temperature steam and supply steam to the steam supply header.

[0086] According to the above scheme, the system can supply steam to the user end through a branch of the first pipeline 10. This configuration allows for the simultaneous supply of steam and the storage (segmented) of the heat from the high-temperature steam in the thermal storage unit. Furthermore, the system can use the medium in the thermal storage unit to heat the water / low-temperature steam in the second pipeline 20 to generate the steam required by the user. Since the medium in the thermal storage unit can be heated by high-temperature steam or by the electric heater 35, the system can use the electric heater 35 to compensate for insufficient heat storage in the thermal storage unit, thus reducing the number of load changes during unit operation and improving unit operational safety.

[0087] One or more embodiments in this specification are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments in this specification should be included within the protection scope of this application.

[0088] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A high temperature steam heat energy cascade utilization external steam supply system, characterized in that, The application relates to a heat storage system. The heat storage system comprises: at least one heat storage unit; a first pipeline, a first heat exchange assembly arranged between the first pipeline and the at least one heat storage unit, the first heat exchange assembly being used for heat exchange between high-temperature steam in the first pipeline and medium in the at least one heat storage unit; a second pipeline, a second heat exchange assembly arranged between the second pipeline and the at least one heat storage unit, the second heat exchange assembly being used for heat exchange between water / low-temperature steam in the second pipeline and medium in the at least one heat storage unit, the second pipeline being connected to a steam supply main pipe; wherein the at least one heat storage unit comprises an electric heater used for heating medium in the at least one heat storage unit; the at least one heat storage unit comprises a first heat storage unit, a second heat storage unit and a third heat storage unit; the first heat exchange assembly comprises a first heat exchanger, a third heat exchanger and a fifth heat exchanger, the first heat exchanger being arranged between the first pipeline and the first heat storage unit, the third heat exchanger being arranged between the first pipeline and the second heat storage unit, and the fifth heat exchanger being arranged between the first pipeline and the third heat storage unit; the second heat exchange assembly comprises a second heat exchanger, a fourth heat exchanger and a sixth heat exchanger, the second heat exchanger being arranged between the second pipeline and the first heat storage unit, the fourth heat exchanger being arranged between the second pipeline and the second heat storage unit, and the sixth heat exchanger being arranged between the second pipeline and the third heat storage unit; 2. The high temperature steam heat energy cascade utilization external steam supply system according to claim 1, characterized in that, the first pipeline is provided with a first branch, and the first branch is connected to the steam supply main pipe. the first heat storage unit comprises a first circulating pipeline, a first low-temperature salt tank and a first high-temperature salt tank, the first low-temperature salt tank and the first high-temperature salt tank being sequentially connected in series on the first circulating pipeline; 3. The high temperature steam heat energy cascade utilization external steam supply system according to claim 2, characterized in that, the electric heater is arranged on the first circulating pipeline and used for heating molten salt output by the first low-temperature salt tank. the first heat exchanger is arranged on the first circulating pipeline and located between a salt outlet of the first low-temperature salt tank and a salt inlet of the first high-temperature salt tank; 4. The high temperature steam heat energy cascade utilization external steam supply system according to claim 2, characterized in that, the first circulating pipeline is provided with a medium bypass, and two ends of the medium bypass are connected to two ends of the first heat exchanger respectively.

5. The high temperature steam heat energy cascade utilization external steam supply system according to claim 2, characterized in that, the second pipeline is provided with a first bypass and a second bypass, two ends of the first bypass are connected to two ends of the fourth heat exchanger respectively, and two ends of the second bypass are connected to two ends of the sixth heat exchanger respectively.

6. The high temperature steam heat energy cascade utilization external steam supply system according to claim 5, characterized in that, the second pipeline is provided with a second branch and a seventh heat exchanger, a steam inlet of the second branch is communicated with a steam outlet of the second heat exchanger, and the seventh heat exchanger is arranged between the second branch and the second pipeline and used for heat exchange between medium in the second branch and medium in the second pipeline.

7. The high temperature steam heat energy cascade utilization external steam supply system according to claim 1, characterized in that, the second pipeline is provided with a third bypass, and two ends of the third bypass are connected to two ends of the seventh heat exchanger respectively. the second pipeline is provided with a third branch and an oxygen removal device, a steam inlet of the third branch is communicated with a steam outlet of the second heat exchanger, and a steam outlet of the third branch is communicated with a steam inlet of the oxygen removal device.

8. A method for supplying steam to an external user in a high-temperature steam heat cascade utilization system, suitable for use in the high-temperature steam heat cascade utilization system of any one of claims 1-7, characterized in that, The method comprises a heat storage operation mode, a heat release operation mode and a direct heating operation mode In the heat storage operation mode, the second pipeline is closed, the first pipeline and the first branch are opened, and the first branch divides the high-temperature steam in the first pipeline to supply steam to a steam supply main pipe; In the heat release operation mode, the first branch is closed, the second pipeline is opened, and the water / low-temperature steam in the second pipeline exchanges heat with the medium in the at least one heat storage unit through the second heat exchange assembly to form high-temperature steam and supply steam to the steam supply main pipe; In the direct heating operation mode, the first branch is closed, the second pipeline and the electric heater are opened, the medium in the at least one heat storage unit is heated by the electric heater, and the water / low-temperature steam in the second pipeline exchanges heat with the medium in the at least one heat storage unit through the second heat exchange assembly to form high-temperature steam and supply steam to the steam supply main pipe.

Images