A coupling scheme of a combined heat and power unit and a molten salt heat storage system

Abstract

The present application mainly relates to the field of coal-fired power generation technology, and discloses a cogeneration unit and molten salt heat storage system coupling scheme, which comprises a boiler, a molten salt tank assembly, a molten salt heater and a drain heater. The molten salt tank assembly comprises a first molten salt tank, a second molten salt tank and a third molten salt tank. The outlet of a third pipeline is in communication with the boiler, the inlet of a fourth pipeline is in communication with the second molten salt tank, and the outlet of the fourth pipeline is in communication with the first molten salt tank or the third molten salt tank. The drain heater defines a containing space, and parts of the third pipeline and the fourth pipeline are arranged in the containing space. The drain enters the containing space through a first port, exchanges heat with the third pipeline or the fourth pipeline, and then flows to a heating steam user or an industrial steam user through a second port. According to the cogeneration unit and molten salt heat storage system coupling scheme, the energy of the heat source steam and the high-temperature molten salt can be fully utilized, and the waste of electric power resources can be avoided.

Description

Technical Field

[0001] This invention relates to the field of coal-fired power generation technology, and in particular to a coupling scheme between a combined heat and power unit and a molten salt thermal storage system. Background Technology

[0002] In recent years, my country's renewable energy power generation technology has developed rapidly. However, constrained by weather and climate conditions, wind power, solar thermal power, and photovoltaic power generation methods generally exhibit strong intermittency and large fluctuations. To compensate for the reduced grid stability caused by the integration of renewable energy, thermal power units need to undertake a heavier peak-shaving task. Furthermore, the centralized heating system in northern my country, primarily based on combined heat and power (CHP) units in winter, easily leads to a "heat-driven power generation" phenomenon, resulting in a waste of electricity resources. Moreover, CHP units may supply industrial steam to nearby industrial parks while generating electricity and providing heating. Therefore, when operating under heating conditions, to ensure that the parameters of the supplied industrial steam meet requirements, the unit's power generation load remains consistently high, which reduces the peak-shaving performance of CHP units under heating conditions.

[0003] Molten salt thermal energy storage technology, as a commonly used medium-to-high temperature thermal energy storage technology, exhibits good adaptability to the steam and water temperatures of thermal power units. Therefore, coupling molten salt thermal energy storage systems with thermal power units can improve their peak-shaving performance. Existing technologies for coupling molten salt thermal energy storage systems with thermal power units primarily focus on storing heat under low load and releasing heat under high load during pure condensing operation, thereby enhancing the unit's peak-shaving performance. However, when the unit operates under heating conditions, it needs to maintain a higher load. Therefore, a coupling scheme between a combined heat and power (CHP) unit and a molten salt thermal energy storage system under heating conditions is needed to improve the CHP unit's peak-shaving performance and avoid wasting electrical resources. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a coupling scheme between a combined heat and power (CHP) unit and a molten salt thermal energy storage system. This coupling scheme allows for the full utilization of the energy from the heat source steam and the high-temperature molten salt, avoiding the waste of electrical resources.

[0005] According to an embodiment of the present invention, a coupling scheme between a combined heat and power unit and a molten salt thermal storage system includes a boiler, a molten salt tank assembly, a molten salt heater, and a condensate heater. The molten salt tank assembly includes a first molten salt tank, a second molten salt tank, and a third molten salt tank. The molten salt heater is provided with a first pipeline and a second pipeline. The first pipeline is used to circulate heat source steam, and the inlet of the second pipeline is connected to the first molten salt tank, and the outlet of the second pipeline is connected to the second molten salt tank. The condensate heater is provided with a third pipeline and a fourth pipeline, and the outlet of the first pipeline is connected to the inlet of the third pipeline. The third pipeline is connected to the boiler at its outlet, the fourth pipeline is connected to the second molten salt tank at its inlet, and the fourth pipeline is connected to either the first or third molten salt tank at its outlet. The condensate heater defines a containment space with a first and a second outlet. Parts of the third and fourth pipelines are located within the containment space but are not connected to it. Drainage enters the containment space through the first outlet, exchanges heat with the third or fourth pipeline, and then flows through the second outlet to the heating steam user or industrial steam user.

[0006] According to the coupling scheme of the cogeneration unit and the molten salt thermal storage system of the present invention, by setting up a molten salt tank assembly, a molten salt heater and a condensate heater, the flow direction of the outlet of the third and fourth pipes in the condensate heater can be changed according to the type of molten salt to supply industrial steam or heating steam, so that the energy of the heat source steam and the high-temperature molten salt can be fully utilized and the waste of electrical resources can be avoided.

[0007] In some embodiments of the present invention, the coupling scheme between the cogeneration unit and the molten salt thermal storage system further includes a deaerator, and the outlet of the third pipeline is connected to the boiler or the deaerator.

[0008] In some embodiments of the present invention, the coupling scheme between the cogeneration unit and the molten salt thermal storage system further includes a first control valve, which is used to control the connection between the outlet of the third pipeline and the boiler; and a second control valve, which is used to control the connection between the outlet of the third pipeline and the deaerator.

[0009] In some embodiments of the present invention, the coupling scheme between the cogeneration unit and the molten salt thermal storage system further includes a third control valve, which is used to control the connection between the outlet of the fourth pipeline and the first molten salt tank; and a fourth control valve, which is used to control the connection between the outlet of the fourth pipeline and the third molten salt tank.

[0010] In some embodiments of the present invention, the coupling scheme between the cogeneration unit and the molten salt thermal storage system further includes: a high-pressure cylinder, the high-pressure cylinder being connected to the outlet of the boiler; a medium-pressure cylinder, the inlet of the medium-pressure cylinder being connected to the outlet of the boiler, and the outlet of the medium-pressure cylinder being connected to the deaerator and the heating steam user respectively; and a low-pressure cylinder, the outlet of the medium-pressure cylinder being connected to the inlet of the low-pressure cylinder.

[0011] In some embodiments of the present invention, the coupling scheme between the cogeneration unit and the molten salt thermal storage system further includes a low-pressure heater, which is connected to the low-pressure cylinder.

[0012] In some embodiments of the present invention, there are multiple low-pressure heaters connected in series, and each low-pressure heater is provided with a first condensate extraction position for extracting condensate, which enters the containment space through the first port.

[0013] In some embodiments of the present invention, the coupling scheme of the cogeneration unit and the molten salt thermal storage system further includes a condensate preheater, which is connected in parallel with the low-pressure heater. The condensate preheater is provided with a fifth pipeline, the inlet of which is connected to the third molten salt tank, and the outlet of which is connected to the first molten salt tank.

[0014] In some embodiments of the present invention, the coupling scheme between the cogeneration unit and the molten salt thermal storage system further includes a high-pressure heater. There are multiple high-pressure heaters, some of which are connected to the high-pressure cylinder, and the remaining high-pressure heaters are connected to the intermediate-pressure cylinder. The multiple high-pressure heaters are connected in series.

[0015] In some embodiments of the present invention, each of the high-pressure heaters is provided with a second condensate extraction position for extracting condensate, which enters the containment space from the first port.

[0016] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0018] Figure 1 This is a schematic diagram of the thermal storage process of a coupling scheme between a cogeneration unit and a molten salt thermal storage system according to an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of the solar salt heat release process of the coupling scheme between the cogeneration unit and the molten salt thermal storage system according to an embodiment of the present invention.

[0020] Figure 3 This is a schematic diagram of the Hitec salt exothermic process of the coupling scheme between a cogeneration unit and a molten salt thermal storage system according to an embodiment of the present invention.

[0021] Figure label:

[0022] 100. Combined heat and power units and molten salt thermal storage systems;

[0023] 1. Boiler;

[0024] 201. First molten salt vessel; 202. Second molten salt vessel; 203. Third molten salt vessel;

[0025] 3. Molten salt heater; 301. First pipeline; 302. Second pipeline;

[0026] 4. Water-absorbing heater; 401. Third pipe; 402. Fourth pipe; 403. Containing space; 4031. First inlet; 4032. Second inlet;

[0027] 5. Deaerator; 6. High-pressure cylinder; 7. Medium-pressure cylinder; 8. Low-pressure cylinder; 9. Low-pressure heater; 901. First condensate extraction point; 10. Condensate preheater; 1001. Fifth pipeline; 11. High-pressure heater; 1101. Second condensate extraction point; 12. Condenser; 13. Condensate pump; 14. Heating steam user; 15. Industrial steam user. Detailed Implementation

[0028] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown 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 the present invention, and should not be construed as limiting the present invention.

[0029] In the description of this invention, 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," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention 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 the invention. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly 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 of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] The following is for reference. Figures 1-3 The coupling scheme between the cogeneration unit and the molten salt thermal storage system 100 according to an embodiment of the present invention is described.

[0032] like Figures 1-3 As shown, the coupling scheme of the cogeneration unit and the molten salt thermal storage system 100 according to an embodiment of the present invention includes a boiler 1, a molten salt tank assembly, a molten salt heater 3, and a condensate heater 4.

[0033] Specifically, the molten salt tank assembly includes a first molten salt tank 201, a second molten salt tank 202, and a third molten salt tank 203. The first molten salt tank 201 is used to contain low-temperature molten salt, the second molten salt tank 202 is used to contain high-temperature molten salt, and the third molten salt tank 203 is used to contain medium-temperature molten salt.

[0034] The molten salt heater 3 is equipped with a first pipe 301 and a second pipe 302. The first pipe 301 is used to circulate heat source steam. The inlet of the second pipe 302 is connected to the first molten salt tank 201, and the outlet of the second pipe 302 is connected to the second molten salt tank 202. When the molten salt heater 3 is working, heat source steam flows through the first pipe 301. The low-temperature molten salt in the first molten salt tank 201 enters the molten salt heater 3, exchanges heat with the heat source steam, and then the high-temperature molten salt flows to the second molten salt tank 202, thus heating the low-temperature molten salt.

[0035] The condensate heater 4 is equipped with a third pipe 401 and a fourth pipe 402. The outlet of the first pipe 301 is connected to the inlet of the third pipe 401, and the outlet of the third pipe 401 is connected to the boiler 1. The inlet of the fourth pipe 402 is connected to the second molten salt tank 202, and the outlet of the fourth pipe 402 is connected to the first molten salt tank 201 or the third molten salt tank 203. The condensate heater 4 defines a receiving space 403. The receiving space 403 is provided with a first port 4031 and a second port 4032. Parts of the third pipe 401 and the fourth pipe 402 are located in the receiving space 403 and are not connected to the receiving space 403. Drainage enters the receiving space 403 through the first port 4031, exchanges heat with the third pipe 401 or the fourth pipe 402, and then flows to the heating steam user 14 or the industrial steam user 15 through the second port 4032.

[0036] Specifically, when the molten salt material is solar salt, during the heat storage process, heat source steam enters the molten salt heater 3 and releases heat to the low-temperature molten salt. The low-temperature molten salt in the first molten salt tank 201 enters the molten salt heater 3 to absorb heat, becoming high-temperature molten salt after absorbing heat, and finally flows into the second molten salt tank 202. The heat source steam after releasing heat enters the condensate heater 4 through the third pipe 401, exchanging heat with the condensate. After releasing heat, the heat source steam condenses and finally enters the boiler 1 through the outlet of the third pipe 401. The condensate enters the containment space 403 through the first port 4031, becoming high-temperature steam after absorbing heat, and finally enters the industrial steam user 15. During the heat release process, the high-temperature molten salt in the second molten salt tank 202 enters the condensate heater 4 through the fourth pipe 402 to release heat, becoming low-temperature molten salt and entering the first molten salt tank 201 through the outlet of the fourth pipe 402. The condensate enters the containment space 403 through the first inlet 4031, absorbs heat and becomes high-temperature steam, which eventually enters the industrial steam user 15, allowing more main steam and reheat steam to enter the turbine to do work and increase the unit's power generation capacity.

[0037] When the molten salt material is Hitec salt, during the heat storage process, heat source steam enters the molten salt heater 3 and releases heat to the low-temperature molten salt. The low-temperature molten salt in the first molten salt tank 201 enters the molten salt heater 3 and absorbs heat, becoming high-temperature molten salt, which eventually flows into the second molten salt tank 202. The released heat source steam enters the condensate heater 4 through the third pipe 401, exchanging heat with the condensate. After releasing heat, the heat source steam condenses and eventually enters the boiler 1 through the outlet of the third pipe 401. The condensate enters the containment space 403 through the first port 4031, absorbs heat, and becomes high-temperature steam, which eventually enters the heating steam user 14. During the heat release process, the high-temperature molten salt in the second molten salt tank 202 enters the condensate heater 4 through the fourth pipe 402 and releases heat, becoming medium-temperature molten salt and entering the third molten salt tank 203 through the outlet of the fourth pipe 402. The condensate enters the containment space 403 through the first inlet 4031, absorbs heat, becomes high-temperature steam, and finally enters the heating steam user 14.

[0038] According to the coupling scheme of the cogeneration unit and the molten salt thermal storage system 100 of the present invention, by setting up a molten salt tank assembly, a molten salt heater 3 and a condensate heater 4, the flow direction of the outlet of the third pipe 401 and the fourth pipe 402 in the condensate heater 4 can be changed according to the type of molten salt to supply industrial steam or heating steam, so that the energy of the heat source steam and the high-temperature molten salt can be fully utilized and the waste of electrical resources can be avoided.

[0039] In some embodiments, the first molten salt tank 201, the second molten salt tank 202, and the third molten salt tank 203 together constitute a molten salt tank assembly.

[0040] In some embodiments of the present invention, such as Figures 1-3As shown, the coupling scheme between the cogeneration unit and the molten salt thermal storage system 100 also includes a deaerator 5, and the outlet of the third pipeline 401 is connected to either the boiler 1 or the deaerator 5. When the heat source steam is the main steam, the outlet of the third pipeline 401 is connected to the boiler 1; when the heat source steam is reheat steam, the outlet of the third pipeline 401 is connected to the deaerator 5. Different molten salt materials and heat source steam are provided, allowing the high-temperature steam formed after the condensate is heated to supply industrial steam and heating steam with different parameter requirements, thus meeting steam demand.

[0041] In some embodiments of the present invention, the coupling scheme between the cogeneration unit and the molten salt thermal storage system 100 further includes a first control valve and a second control valve. The first control valve is used to control the connection between the outlet of the third pipeline 401 and the boiler 1; the second control valve is used to control the connection between the outlet of the third pipeline 401 and the deaerator 5. It is understood that the outlet of the third pipeline 401 may be equipped with a tee pipe, which is connected to the third pipeline 401, the deaerator 5, and the boiler 1 respectively. By setting the first control valve and the second control valve, the connection between the third pipeline 401 and the deaerator 5 and the boiler 1 can be selectively switched to meet different usage requirements.

[0042] In some embodiments of the present invention, the coupling scheme between the cogeneration unit and the molten salt thermal storage system 100 further includes a third control valve and a fourth control valve. The third control valve is used to control the connection and disconnection between the outlet of the fourth pipeline 402 and the first molten salt tank 201; the fourth control valve is used to control the connection and disconnection between the outlet of the fourth pipeline 402 and the third molten salt tank 203. It is understood that the outlet of the fourth pipeline 402 may be equipped with a tee pipe, which is connected to the fourth pipeline 402, the first molten salt tank 201, and the third molten salt tank 203 respectively. By setting the third control valve and the fourth control valve, the connection and disconnection between the fourth pipeline 402 and the first molten salt tank 201 and the third molten salt tank 203 can be selectively established to meet different usage requirements.

[0043] In some embodiments of the present invention, such as Figures 1-3As shown, the coupling scheme of the cogeneration unit and the molten salt thermal storage system 100 also includes a high-pressure cylinder 6, an intermediate-pressure cylinder 7, and a low-pressure cylinder 8. The high-pressure cylinder 6 is connected to the outlet of the boiler 1, the inlet of the intermediate-pressure cylinder 7 is connected to the outlet of the boiler 1, the outlet of the intermediate-pressure cylinder 7 is connected to the deaerator 5 and the heating steam user 14, and the outlet of the intermediate-pressure cylinder 7 is connected to the inlet of the low-pressure cylinder 8. The boiler 1 converts chemical energy into thermal energy by burning fuel (coal, natural gas, etc.) and heats water into steam with extremely high energy (high temperature and high pressure). The high-pressure cylinder 6 receives the steam with the highest parameters from the boiler 1. The steam first expands and does work in the high-pressure cylinder 6, and the pressure and temperature of the steam decrease significantly. The intermediate-pressure cylinder 7 receives the steam discharged from the high-pressure cylinder 6 and returned to the reheater of the boiler 1 for reheating. The temperature of the reheated steam is usually close to the initial temperature, but the pressure is lower than the initial pressure. The high-temperature, intermediate-pressure steam continues to expand and do work in the intermediate-pressure cylinder 7, and the pressure and temperature decrease further. The low-pressure cylinder 8 receives the exhaust steam from the intermediate-pressure cylinder 7. The steam pressure after completing its work is lower than atmospheric pressure, and it becomes wet steam, which is then pumped back to the boiler 1 to start a new cycle.

[0044] In this embodiment, as Figures 1-3 As shown, the cogeneration unit also includes a condenser 12. The steam pressure in the low-pressure cylinder 8 after completing its work is lower than atmospheric pressure, and it becomes wet steam. It is eventually introduced into the condenser 12, condensed into water, and then pumped back to the boiler 1 to start a new cycle.

[0045] In some embodiments of the present invention, such as Figures 1-3 As shown, the coupling scheme between the cogeneration unit and the molten salt thermal storage system 100 also includes a low-pressure heater 9. The low-pressure heater 9 is connected to the low-pressure cylinder 8. The low-pressure heater 9 uses a portion of the steam that has already done work, extracted from the low-pressure cylinder 8, as a heat source to heat the low-temperature condensate that is about to be sent to the boiler 1. The portion of the steam that has already done work extracted from the low-pressure cylinder 8 condenses and releases heat in the low-pressure heater 9, which significantly increases the condensate temperature, recovers the steam heat that would otherwise be wasted, greatly improves the thermal efficiency of the power plant, and reduces the humidity of the final stage steam in the low-pressure cylinder 8 to protect the blades.

[0046] In some embodiments of the present invention, such as Figures 1-3 As shown, there are multiple low-pressure heaters 9 connected in series. Each low-pressure heater 9 is provided with a first condensate extraction position 901 for extracting low-pressure condensate. The condensate enters the receiving space 403 through the first port 4031, thereby providing condensate to the condensate heater 4. After being heated by the condensate heater 4, the condensate enters the heating steam user 14 to meet different steam needs.

[0047] When the molten salt material is Hitec salt, during the heat storage process, the heat source steam enters the molten salt heater 3 and releases heat to the low-temperature molten salt. The low-temperature molten salt in the first molten salt tank 201 enters the molten salt heater 3 and absorbs heat. After absorbing heat, the low-temperature molten salt becomes high-temperature molten salt and finally flows into the second molten salt tank 202. The heat source steam, after releasing heat, enters the condensate heater 4 through the third pipe 401, exchanges heat with the condensate, and condenses after releasing heat. Finally, it enters the boiler 1 through the outlet of the third pipe 401. The condensate enters the containment space 403 through the first port 4031, absorbs heat, becomes high-temperature steam, and finally enters the heating steam user 14. At this time, the condensate is extracted from the first condensate extraction position 901.

[0048] In some embodiments of the present invention, such as Figure 3 As shown, the coupling scheme between the cogeneration unit and the molten salt thermal storage system 100 also includes a condensate preheater 10, which is connected in parallel with the low-pressure heater 9. The condensate preheater 10 has a fifth pipeline 1001, the inlet of which is connected to the third molten salt tank 203, and the outlet of which is connected to the first molten salt tank 201. The cogeneration unit also includes a condensate pump 13, and the low-pressure cylinder 8, condenser 12, condensate pump 13, and low-pressure heater 9 are arranged sequentially.

[0049] When the molten salt material is Hitec salt, during the exothermic process, the high-temperature molten salt in the second molten salt tank 202 enters the condensate heater 4 through the fourth pipe 402 to release heat. After releasing heat, it becomes medium-temperature molten salt and enters the third molten salt tank 203 through the outlet of the fourth pipe 402. The medium-temperature molten salt enters the condensate preheater 10 to release heat, and finally enters the first molten salt tank 201. At the same time, part of the condensate from the outlet of the condensate pump 13 enters the condensate preheater 10 to absorb heat, and finally enters the deaerator 5.

[0050] In some embodiments of the present invention, such as Figures 1-3 As shown, the coupling scheme between the cogeneration unit and the molten salt thermal storage system 100 also includes a high-pressure heater 11. There are multiple high-pressure heaters 11. Some of the high-pressure heaters 11 are connected to the high-pressure cylinder 6, and the remaining high-pressure heaters 11 are connected to the intermediate-pressure cylinder 7. The multiple high-pressure heaters 11 are connected in series.

[0051] The high-pressure heater 11 uses high-grade steam extracted from the high-pressure cylinder 6 or the intermediate-pressure cylinder 7 to heat the feedwater that is about to be sent to the boiler 1 through the principle of heat exchange, which greatly increases the feedwater temperature, reduces the fuel consumption of the boiler 1, and significantly improves the thermal economy of the entire power plant by recovering the extracted steam energy, while reducing the thermal stress of the boiler 1 to ensure safe operation.

[0052] In some embodiments of the present invention, such as Figures 1-3As shown, each high-pressure heater 11 is provided with a second condensate extraction position 1101 for extracting high-pressure condensate. The condensate enters the receiving space 403 through the first port 4031. Thus, condensate can be supplied to the condensate heater 4. After being heated by the condensate heater 4, the condensate enters the industrial steam user 15 to meet different steam needs.

[0053] When the molten salt material is solar salt, during the heat storage process, heat source steam enters the molten salt heater 3 and releases heat to the low-temperature molten salt. The low-temperature molten salt in the first molten salt tank 201 enters the molten salt heater 3 and absorbs heat. After absorbing heat, the low-temperature molten salt becomes high-temperature molten salt and finally flows into the second molten salt tank 202. The heat source steam, after releasing heat, enters the condensate heater 4 through the third pipe 401, exchanges heat with the condensate, and condenses after releasing heat. Finally, it enters the boiler 1 through the outlet of the third pipe 401. The condensate enters the containment space 403 through the first port 4031, absorbs heat, becomes high-temperature steam, and finally enters the industrial steam user 15. At this time, the condensate is extracted by the second condensate extraction position 1101.

[0054] Other configurations and operations of the coupling scheme between the cogeneration unit and the molten salt thermal storage system 100 according to embodiments of the present invention are known to those skilled in the art and will not be described in detail here.

[0055] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0056] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A coupling scheme of a combined heat and power unit and a molten salt thermal storage system, characterized in that, The application relates to a coupling scheme of a combined heat and power unit and a molten salt heat storage system. The application comprises: a boiler; a molten salt tank assembly, which comprises a first molten salt tank, a second molten salt tank and a third molten salt tank; a molten salt heater, which is internally provided with a first pipeline and a second pipeline, the first pipeline is used for circulating heat source steam, the inlet of the second pipeline is communicated with the first molten salt tank, and the outlet of the second pipeline is communicated with the second molten salt tank; a steam heater, which is internally provided with a third pipeline and a fourth pipeline, the outlet of the first pipeline is communicated with the inlet of the third pipeline, the outlet of the third pipeline is communicated with the boiler, the inlet of the fourth pipeline is communicated with the second molten salt tank, and the outlet of the fourth pipeline is communicated with the first molten salt tank or the third molten salt tank, the steam heater defines a containing space, the containing space is provided with a first opening and a second opening, and the third pipeline and the fourth pipeline are partially arranged in the containing space and are not communicated with the containing space; steam enters the containing space through the first opening, exchanges heat with the third pipeline or the fourth pipeline, and then flows to a heating steam user or an industrial steam user through the second opening; 2. The coupling scheme of claim 1, wherein, a condensate preheater, which is internally provided with a fifth pipeline, the inlet of the fifth pipeline is communicated with the third molten salt tank, and the outlet of the fifth pipeline is communicated with the first molten salt tank. The application further comprises:

3. The coupling scheme of claim 2, wherein, a deaerator, and the outlet of the third pipeline is communicated with the boiler or the deaerator. The application further comprises: a first control valve, which is used for controlling the opening and closing of the outlet of the third pipeline and the boiler; 4. The coupling scheme of claim 1, wherein, a second control valve, which is used for controlling the opening and closing of the outlet of the third pipeline and the deaerator. The application further comprises: a third control valve, which is used for controlling the opening and closing of the outlet of the fourth pipeline and the first molten salt tank; 5. The scheme of coupling a combined heat and power unit with a molten salt thermal storage system according to claim 2, characterized in that, a fourth control valve, which is used for controlling the opening and closing of the outlet of the fourth pipeline and the third molten salt tank. The application further comprises: a high-pressure cylinder, which is communicated with the outlet of the boiler; a medium-pressure cylinder, the inlet of the medium-pressure cylinder is communicated with the outlet of the boiler, the outlet of the medium-pressure cylinder is communicated with the deaerator and the heating steam user respectively; 6. The coupling scheme of claim 5, wherein, a low-pressure cylinder, the outlet of the medium-pressure cylinder is communicated with the inlet of the low-pressure cylinder. The application further comprises:

7. The coupling scheme of claim 6, wherein, a low-pressure heater, which is communicated with the low-pressure cylinder. The low-pressure heater is multiple, and the multiple low-pressure heaters are sequentially connected in series, each low-pressure heater is correspondingly provided with a first steam extraction position, which is used for extracting steam, and steam enters the containing space through the first opening.

9. The coupling scheme of claim 5, wherein, 8. The coupling scheme of the combined heat and power unit and the molten salt heat storage system according to claim 1, wherein the condensate preheater is connected in parallel with the low-pressure heater. The application further comprises:

10. The coupling scheme of claim 9, wherein, a high-pressure heater, which is multiple, part of the high-pressure heaters are communicated with the high-pressure cylinder, and the rest of the high-pressure heaters are communicated with the medium-pressure cylinder, and the multiple high-pressure heaters are sequentially connected in series. Each high-pressure heater is correspondingly provided with a second steam extraction position, which is used for extracting steam, and steam enters the containing space through the first opening.

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