Carbon dioxide power generation system based on fused salt heat storage

Abstract

The utility model provides a carbon dioxide power generation system based on fused salt heat storage. The carbon dioxide power generation system comprises a carbon dioxide compressor (1), a high-temperature fused salt tank (8) and a medium-temperature fused salt tank (7). The first heat exchanger (6) is communicated with a carbon dioxide outlet of the carbon dioxide compressor (1), is communicated with a high-temperature molten salt tank (8) and a medium-temperature molten salt tank (7), and is used for increasing the temperature of the boosted supercritical carbon dioxide by utilizing heat of high-temperature molten salt; the high-speed turbine (2) is used for driving the generator (3) to generate electricity by utilizing supercritical carbon dioxide; and the heat regenerator (5) is used for increasing the temperature of the supercritical carbon dioxide upstream of the first heat exchanger (6) by utilizing the heat of the backflow carbon dioxide of the high-speed turbine (2). The temperature of the supercritical carbon dioxide is increased in a gradient mode, heat of the carbon dioxide is efficiently utilized, and the requirement for expansion acting of the high-speed turbine (2) is met.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of carbon dioxide power generation, and particularly relates to a carbon dioxide power generation system based on molten salt heat storage. BACKGROUND

[0002] As a new clean energy power generation technology, carbon dioxide power generation involves a Brayton cycle, and the process is that carbon dioxide gas is compressed, a heat source is heated, an expansion drive high-speed turbine is driven to generate power, and then the cycle is cooled, that is, supercritical carbon dioxide is used as a power generation working medium, the heat of the heat source is converted into mechanical energy to drive a generator to generate power, and efficient heat exchange is the basis for engineering application of the supercritical power generation system, which can reduce carbon emissions and promote new energy (external heat source) consumption.

[0003] How to efficiently utilize the heat of carbon dioxide in the cycle has become a technical problem that technicians are concerned about. CONTENT OF THE UTILITY MODEL

[0004] The application provides a carbon dioxide power generation system based on molten salt heat storage, characterized by comprising:

[0005] A carbon dioxide compressor is configured to increase the pressure of supercritical carbon dioxide.

[0006] A high-temperature molten salt tank is configured to store high-temperature molten salt.

[0007] A medium-temperature molten salt tank is configured to store medium-temperature molten salt.

[0008] A first heat exchanger is in communication with the carbon dioxide outlet of the carbon dioxide compressor, and in communication with the high-temperature molten salt tank and the medium-temperature molten salt tank, and is configured to utilize the heat of the high-temperature molten salt to increase the temperature of the supercritical carbon dioxide after pressure increase, and the high-temperature molten salt in the high-temperature molten salt tank is stored in the medium-temperature molten salt tank after heat release in the first heat exchanger.

[0009] A high-speed turbine is in communication with the first heat exchanger through a carbon dioxide inlet, and is configured to utilize the supercritical carbon dioxide to drive a generator to generate power, and a backflow carbon dioxide outlet of the high-speed turbine is in communication with the carbon dioxide inlet of the carbon dioxide compressor.

[0010] A regenerator is configured to utilize the heat of the backflow carbon dioxide of the high-speed turbine to increase the temperature of the supercritical carbon dioxide upstream of the first heat exchanger.

[0011] Further, the heat absorption end inlet of the first heat exchanger is in communication with the carbon dioxide outlet of the carbon dioxide compressor, and the heat absorption end outlet of the first heat exchanger is in communication with the carbon dioxide inlet of the high-speed turbine.

[0012] The heat-releasing end inlet of the first heat exchanger is communicated with the high-temperature molten salt tank, and the heat-releasing end outlet of the first heat exchanger is communicated with the medium-temperature molten salt tank.

[0013] Further, the heat-absorbing end inlet of the first heat exchanger is on the same side as the heat-releasing end outlet, and the heat-absorbing end outlet of the first heat exchanger is on the same side as the heat-releasing end inlet.

[0014] Further, the heat-releasing end inlet of the regenerator is communicated with the backflow carbon dioxide outlet of the high-speed turbine, and the heat-releasing end outlet of the regenerator is communicated with the backflow carbon dioxide inlet of the carbon dioxide compressor.

[0015] The heat-absorbing end inlet of the regenerator is communicated with the carbon dioxide outlet of the carbon dioxide compressor, and the heat-absorbing end outlet of the regenerator is communicated with the heat-absorbing end inlet of the first heat exchanger.

[0016] Further, a high-temperature molten salt pump is arranged between the high-temperature molten salt tank and the heat-releasing end inlet of the first heat exchanger.

[0017] Further, a cooler is arranged between the heat-releasing end outlet of the regenerator and the backflow carbon dioxide inlet of the carbon dioxide compressor.

[0018] Further, a first heater is arranged, which is connected with the medium-temperature molten salt tank and the high-temperature molten salt tank respectively, for heating the medium-temperature molten salt in the medium-temperature molten salt tank into high-temperature molten salt and storing the high-temperature molten salt into the high-temperature molten salt tank.

[0019] The heat of the first heater is from electric heating, high-temperature flue gas, steam, or waste heat recovery.

[0020] Further, the system further comprises a second heat exchanger and a low-temperature molten salt tank.

[0021] The heat-releasing end inlet of the second heat exchanger is communicated with the medium-temperature molten salt tank, and the heat-releasing end outlet of the second heat exchanger is communicated with the low-temperature molten salt tank.

[0022] The heat-absorbing end inlet of the second heat exchanger is communicated with the carbon dioxide outlet of the carbon dioxide compressor, and the heat-absorbing end outlet of the second heat exchanger is communicated with the carbon dioxide inlet of the high-speed turbine, for heating part of the critical carbon dioxide produced by the carbon dioxide compressor by using the heat of the molten salt in the medium-temperature molten salt tank and providing the part of the critical carbon dioxide to the high-speed turbine.

[0023] Further, a medium-temperature molten salt pump is arranged between the medium-temperature molten salt tank and the heat-releasing end inlet of the second heat exchanger.

[0024] Further, the system further comprises a second heater, one end of which is connected to the low-temperature molten salt tank, and the other end of which is connected to the medium-temperature molten salt tank and the high-temperature molten salt tank respectively, for storing the low-temperature molten salt heated from the low-temperature molten salt tank to the medium-temperature molten salt tank or the high-temperature molten salt tank.

[0025] The heat of the second heater is from electric heating, high-temperature flue gas, steam, or waste heat recovery.

[0026] The above technical solution of the utility model has at least the following beneficial technical effects:

[0027] In the application, the temperature of supercritical carbon dioxide is raised by using the heat of high-temperature molten salt, the heat of backflow carbon dioxide of a high-speed turbine is used by a regenerator to raise the temperature of supercritical carbon dioxide upstream of a first heat exchanger, the temperature of supercritical carbon dioxide is raised in a gradient, the heat of carbon dioxide is efficiently used, and the demand of high-speed turbine expansion work is met. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0029] Figure 1 is a structure diagram of a carbon dioxide power generation system based on molten salt heat storage in an embodiment of the application.

[0030] Figure 2 is a structure diagram of a carbon dioxide power generation system based on molten salt heat storage in another embodiment of the application.

[0031] wherein, Figure 1 The correspondence between the reference signs in and the component names is as follows:

[0032] 1, carbon dioxide compressor; 2, high-speed turbine; 3, generator; 4, cooler; 5, regenerator; 6, first heat exchanger; 7, medium-temperature molten salt tank; 8, high-temperature molten salt tank; 9, high-temperature molten salt pump; 10, second heat exchanger; 11, low-temperature molten salt tank; 12, medium-temperature molten salt pump. DETAILED DESCRIPTION

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the various embodiments of this application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the various embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments. The division of the various embodiments below is for ease of description and should not constitute any limitation on the specific implementation of this application. The various embodiments can be combined with and referenced by each other without contradiction.

[0034] Currently, existing technologies face the challenge of efficiently utilizing the heat generated by carbon dioxide within a cycle.

[0035] To solve the above problems, such as Figure 1 As shown in the schematic diagram of a carbon dioxide power generation system based on molten salt thermal storage, an embodiment of this application provides a power generation system specifically comprising:

[0036] The carbon dioxide compressor 1 is used to increase the pressure of supercritical carbon dioxide. The high-pressure supercritical carbon dioxide releases pressure and expands in the high-speed turbine 2 to do work and rotate, and drives the generator 3 connected to the high-speed turbine 2 to generate electricity.

[0037] High-temperature molten salt tank 8 stores high-temperature molten salt; medium-temperature molten salt tank 7 stores medium-temperature molten salt. The molten salt can be of various types, such as binary nitro molten salt (60% NaNO3 + 40% KNO3) and ternary nitro molten salt (NaNO3-KNO3-NaNO2), to suit different application scenarios and temperature ranges. For example, binary nitro molten salt can reach a high temperature of 565℃, while a low temperature range of 220-290℃ is suitable. The shape and structure of the high-temperature molten salt tank 8 and the medium-temperature molten salt tank 7 are not specifically limited, but are designed for suitable piping and valve flow control.

[0038] The heat-absorbing end of the first heat exchanger 6 is connected to the carbon dioxide outlet of the carbon dioxide compressor 1, and the heat-releasing end of the first heat exchanger 6 is connected to the high-temperature molten salt tank 8 and the medium-temperature molten salt tank 7. The first heat exchanger 6 uses the heat of the high-temperature molten salt to increase the temperature of the supercritical carbon dioxide after pressurization. The high-temperature molten salt in the high-temperature molten salt tank 8 releases heat in the first heat exchanger 6 and flows into the medium-temperature molten salt tank 7. Downstream of the first heat exchanger 6, the carbon dioxide, after its pressure and temperature have increased, enters the high-speed turbine 2 to perform work. The carbon dioxide inlet of the high-speed turbine 2 is connected to the heat-absorbing end outlet of the first heat exchanger 6, and its return carbon dioxide outlet is connected to the carbon dioxide inlet of the carbon dioxide compressor 1. The high-speed turbine 2 uses the expansion of supercritical carbon dioxide to drive the generator 3 to generate electricity. The carbon dioxide after expansion and work flows back to the carbon dioxide compressor 1 to be compressed and pressurized again for recycling.

[0039] The temperature of the supercritical carbon dioxide entering the high-speed turbine 2 affects the power generation efficiency, and the temperature of the carbon dioxide after compression by the carbon dioxide compressor 1 is generally 100-150°C, so in the present application, the heat of the high-temperature molten salt is used to raise the temperature of the supercritical carbon dioxide to meet the parameter requirements of the operating efficiency of the high-speed turbine 2 on the working carbon dioxide (generally 400-800°C, and the system in the present application is reconfigured to about 550°C). The critical temperature of CO2 is 31.1°C, and the critical pressure is 7.38 MPa. In the supercritical state, CO2 has the characteristics of low viscosity of gas and high density of liquid, and the heat transfer efficiency is higher than that of the traditional steam turbine power generation. In the present application, the initial supercritical carbon dioxide comes from external equipment or is purchased, and is recycled after entering the system.

[0040] The supercritical carbon dioxide expands and works in the high-speed turbine 2, and after the pressure is released, it is transported back to the carbon dioxide compressor 1 through the backflow carbon dioxide pipeline and is compressed again to participate in the cycle. In the system, a regenerator 5 is provided on the backflow carbon dioxide pipeline, which uses the heat of the backflow carbon dioxide (200-300°C) of the high-speed turbine 2 to raise the temperature of the supercritical carbon dioxide upstream of the first heat exchanger 6, and at the same time, the temperature of the backflow carbon dioxide is lowered to adapt to the inlet temperature of the backflow carbon dioxide (30-50°C) of the carbon dioxide compressor 1.

[0041] In the present application, the regenerator 5 uses the heat of the backflow carbon dioxide of the high-speed turbine 2 to raise the temperature of the supercritical carbon dioxide upstream of the first heat exchanger 6, and the first heat exchanger 6 uses the heat of the high-temperature molten salt to raise the temperature of the supercritical carbon dioxide for the second time, so that the temperature of the supercritical carbon dioxide is raised in stages, the heat of the carbon dioxide is used efficiently, and the parameter requirements of the operating efficiency of the high-speed turbine 2 on the working carbon dioxide are met.

[0042] The type of the carbon dioxide compressor 1 in the present application is not limited, as long as it can produce supercritical carbon dioxide. The structure of an existing carbon dioxide compressor 1 mainly includes a shell, an impeller, a main shaft, a diffuser and a volute in the shell, and a carbon dioxide inlet and outlet provided on the shell; wherein the low-pressure supercritical carbon dioxide enters from the carbon dioxide inlet, passes through single-stage or multi-stage impellers to raise the pressure; the diffuser is used to convert the kinetic energy of the high-speed carbon dioxide at the outlet of the impeller section into static pressure energy, and finally flows out from the carbon dioxide outlet. The pressure of the supercritical carbon dioxide after pressure increase is 20-30 MPa, and the temperature is 80-150°C.

[0043] In an embodiment of the present application, the high-temperature molten salt and the supercritical carbon dioxide exchange heat in the first heat exchanger 6. The heat exchange can be achieved by a heat exchange medium in the first heat exchanger 6 or by direct heat exchange in different pipes in the first heat exchanger 6. The first heat exchanger 6 can be a micro-channel heat exchanger (PCHE) or a printed circuit heat exchanger (PCHE). Alternatively, the regenerator 5, the second heat exchanger 10 and the first heat exchanger 6 in the present application have the same structure and principle.

[0044] Specifically, taking the direct heat exchange in different pipes as an example, the supercritical carbon dioxide flows through the heat-absorbing end of the first heat exchanger 6, i.e., the heat-absorbing end inlet of the first heat exchanger 6 is communicated with the carbon dioxide outlet of the carbon dioxide compressor 1 (after the regenerator 5 is arranged, the heat-absorbing end inlet of the first heat exchanger 6 is communicated with the heat-absorbing end outlet of the regenerator 5, and the carbon dioxide inlet of the heat-absorbing end of the regenerator 5 is communicated with the carbon dioxide outlet of the carbon dioxide compressor 1), and the heat-absorbing end outlet of the first heat exchanger 6 is communicated with the carbon dioxide inlet of the high-speed turbine 2. The molten salt flows through the heat-releasing end of the first heat exchanger 6, i.e., the heat-releasing end inlet of the first heat exchanger 6 is communicated with the high-temperature molten salt tank 8, the heat-releasing end outlet of the first heat exchanger 6 is communicated with the medium-temperature molten salt tank 7, and the high-temperature molten salt in the high-temperature molten salt tank 8 flows into the medium-temperature molten salt tank 7 after heat release in the first heat exchanger 6.

[0045] Preferably, the heat-absorbing end inlet of the first heat exchanger 6 is on the same side as the heat-releasing end outlet of the first heat exchanger 6, and the heat-absorbing end outlet of the first heat exchanger 6 is on the same side as the heat-releasing end inlet of the first heat exchanger 6, i.e., the flow directions of the supercritical carbon dioxide and the molten salt are opposite, so that the molten salt at a higher temperature exchanges heat with the carbon dioxide at a higher temperature, and the molten salt at a lower temperature exchanges heat with the carbon dioxide at a lower temperature.

[0046] In an embodiment, the heat-releasing end inlet of the regenerator 5 is communicated with the backflow carbon dioxide outlet of the high-speed turbine 2, and the heat-releasing end outlet of the regenerator 5 is communicated with the backflow carbon dioxide inlet of the carbon dioxide compressor 1.

[0047] The heat-absorbing end inlet of the regenerator 5 is communicated with the carbon dioxide outlet of the carbon dioxide compressor 1, and the heat-absorbing end outlet of the regenerator 5 is communicated with the heat-absorbing end inlet of the first heat exchanger 6.

[0048] In an embodiment of the present application, a high-temperature molten salt pump 9 is arranged between the molten salt outlet of the high-temperature molten salt tank 8 and the heat-releasing end inlet of the first heat exchanger 6, for driving the molten salt to flow.

[0049] In an embodiment of the present application, a cooler 4 is arranged between the outlet of the heat-releasing end of the regenerator 5 and the inlet of the backflow carbon dioxide of the carbon dioxide compressor 1. The backflow carbon dioxide of the carbon dioxide compressor 1 is cooled by the regenerator 5 and then by the cooler 4, so that the backflow carbon dioxide reaches the required parameters before entering the carbon dioxide compressor 1, and then is compressed again to increase the pressure and form a cycle.

[0050] The system further comprises a first heater (not shown) connected to the intermediate-temperature molten salt tank 7 and the high-temperature molten salt tank 8 respectively, for heating the intermediate-temperature molten salt in the intermediate-temperature molten salt tank 7 to high-temperature molten salt and storing the high-temperature molten salt in the high-temperature molten salt tank 8. The heat of the first heater comes from electric heating, high-temperature flue gas, steam, or waste heat recovery. The electric heating can use surplus electricity generated by thermal power, nuclear power, wind power, or solar power to heat the molten salt. The high-temperature flue gas can be flue gas generated during the production of a thermal power plant, a chemical plant, or a steel plant. The steam and waste heat recovery can be industrial steam or industrial waste heat, as long as they can increase the temperature of the molten salt to an appropriate temperature (above 700°C). Taking the electric heating as an example, the main structure of the first heater comprises an outer shell having a heating cavity inside, and the molten salt is arranged in the heating cavity. An electrode is arranged on the heating cavity and connected to a spiral-shaped resistance wire arranged inside the heating cavity. The resistance wire is covered with a ceramic coating, which can be alumina, to prevent short circuit caused by contact between the resistance wire and the molten salt. The material of the heating cavity can be high-temperature stainless steel (such as 316L or 310S) or nickel-based alloy (Inconel 600). The resistance wire can be nickel-chromium alloy (such as Cr20Ni80) or iron-chromium-aluminum alloy.

[0051] In a specific embodiment of the present application, the supercritical carbon dioxide flows from the carbon dioxide compressor 1 to the high-speed turbine 2. Since the regenerator 5 is arranged upstream of the first heat exchanger 6 to increase the temperature of the carbon dioxide (200-300°C) in advance, the heat of the high-temperature molten salt cannot be fully utilized when the carbon dioxide passes through the first heat exchanger 6. The temperature of the intermediate-temperature molten salt after heat exchange is about 300°C. Therefore, as shown in the figure, the system is provided with a second heat exchanger 10 and a low-temperature molten salt tank 11, for heating a part of the critical carbon dioxide produced by the carbon dioxide compressor 1 using the heat of the molten salt in the intermediate-temperature molten salt tank 7 and supplying the critical carbon dioxide to the high-speed turbine 2. The critical carbon dioxide heated by the first heat exchanger 6 and the critical carbon dioxide heated by the second heat exchanger 10 are applied to different working conditions of the high-speed turbine 2. Figure 2

[0052] ​Specifically, the heat releasing end inlet of the second heat exchanger 10 is communicated with one molten salt outlet of the medium temperature molten salt tank 7, and the heat releasing end outlet of the second heat exchanger 10 is communicated with a molten salt inlet of the low temperature molten salt tank 11; the heat absorbing end inlet of the second heat exchanger 10 is communicated with a carbon dioxide outlet of the carbon dioxide compressor 1, and the heat absorbing end outlet of the second heat exchanger 10 is communicated with a carbon dioxide inlet of the high speed turbine 2, so as to heat part of the critical carbon dioxide produced by the carbon dioxide compressor 1 by using the heat of the molten salt in the medium temperature molten salt tank 7 and supply the high speed turbine 2.

[0053] Further, a medium temperature molten salt pump 12 is arranged between the molten salt outlet of the medium temperature molten salt tank 7 and the heat releasing end inlet of the second heat exchanger 10.

[0054] Optionally, the system further comprises a second heater (not shown), one end of which is connected with the molten salt outlet of the low temperature molten salt tank 11, and the other end is connected with the molten salt inlet of the medium temperature molten salt tank 7 and the molten salt inlet of the high temperature molten salt tank 8 respectively, so as to heat the low temperature molten salt of the low temperature molten salt tank 11 and store it to the medium temperature molten salt tank 7 or the high temperature molten salt tank 8; and the molten salt outlet of the low temperature molten salt tank 11 is provided with a low temperature molten salt pump between the medium temperature molten salt tank 7 and the high temperature molten salt tank 8. The heat of the second heater comes from electric heating, high temperature flue gas, steam or waste heat recovery.

[0055] In any of the above technical solutions, the pressure, temperature and flow rate of the critical carbon dioxide and the temperature of the molten salt can be adjusted according to the specific application scene, the working condition of the power generation system and the power demand. Figure 1 As shown in the figure, the carbon dioxide compressor 1 and the high speed turbine 2 can also be directly communicated.

[0056] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "a specific embodiment" and the like means that the specific features, structures or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0057] It should be understood that the above specific embodiments of the present application are only used for illustrative or explanatory purposes of the principles of the present application, and do not constitute a limitation of the present application. Therefore, any modification, equivalent replacement, improvement and the like made without departing from the spirit and scope of the present application shall be included in the protection scope of the present application. In addition, the claims of the present application are intended to cover all changes and modifications falling within the scope and boundary of the appended claims, or the equivalent forms of such scope and boundary.

Claims

1. A carbon dioxide power generation system based on molten salt heat storage, characterized by, The application relates to a supercritical carbon dioxide power generation system, comprising: a carbon dioxide compressor (1) for boosting the pressure of supercritical carbon dioxide; a high-temperature molten salt tank (8) for storing high-temperature molten salt; a medium-temperature molten salt tank (7) for storing medium-temperature molten salt; a first heat exchanger (6) in communication with the carbon dioxide outlet of the carbon dioxide compressor (1) and in communication with the high-temperature molten salt tank (8) and the medium-temperature molten salt tank (7), for increasing the temperature of the supercritical carbon dioxide after pressure boosting by using the heat of the high-temperature molten salt, the high-temperature molten salt in the high-temperature molten salt tank (8) being stored in the medium-temperature molten salt tank (7) after heat release in the first heat exchanger (6); a high-speed turbine (2) in communication with the carbon dioxide inlet of the first heat exchanger (6), for driving a generator (3) to generate power by using the supercritical carbon dioxide, and in communication with the carbon dioxide outlet of the carbon dioxide compressor (1); a regenerator (5) for increasing the temperature of the supercritical carbon dioxide upstream of the first heat exchanger (6) by using the heat of the backflow carbon dioxide of the high-speed turbine (2).

2. The molten salt-based thermal energy storage- based carbon dioxide power generation system according to claim 1, characterized by, The heat absorption end inlet of the first heat exchanger (6) is in communication with the carbon dioxide outlet of the carbon dioxide compressor (1), and the heat absorption end outlet of the first heat exchanger (6) is in communication with the carbon dioxide inlet of the high-speed turbine (2); The heat release end inlet of the first heat exchanger (6) is in communication with the high-temperature molten salt tank (8), and the heat release end outlet of the first heat exchanger (6) is in communication with the medium-temperature molten salt tank (7).

3. The molten salt-based thermal energy storage- based carbon dioxide power generation system according to claim 2, characterized by, The heat absorption end inlet and the heat release end outlet of the first heat exchanger (6) are on the same side, and the heat absorption end outlet and the heat release end inlet of the first heat exchanger (6) are on the same side.

4. The molten salt-based thermal energy storage- based carbon dioxide power generation system according to claim 2, characterized by, The heat release end inlet of the regenerator (5) is in communication with the backflow carbon dioxide outlet of the high-speed turbine (2), and the heat release end outlet of the regenerator (5) is in communication with the backflow carbon dioxide inlet of the carbon dioxide compressor (1); The heat absorption end inlet of the regenerator (5) is in communication with the carbon dioxide outlet of the carbon dioxide compressor (1), and the heat absorption end outlet of the regenerator (5) is in communication with the heat absorption end inlet of the first heat exchanger (6).

5. The molten salt-based thermal energy storage- based carbon dioxide power generation system according to claim 4, characterized by, A high-temperature molten salt pump (9) is arranged between the high-temperature molten salt tank (8) and the heat release end inlet of the first heat exchanger (6).

6. The molten salt-based thermal energy storage- based carbon dioxide power generation system according to claim 4, characterized by, A cooler (4) is arranged between the heat release end outlet of the regenerator (5) and the backflow carbon dioxide inlet of the carbon dioxide compressor (1).

7. The molten salt-based thermal energy storage- based carbon dioxide power generation system according to claim 1, characterized by, A first heater is further arranged and connected to the medium-temperature molten salt tank (7) and the high-temperature molten salt tank (8) respectively, for heating the medium-temperature molten salt in the medium-temperature molten salt tank (7) into high-temperature molten salt and storing the high-temperature molten salt in the high-temperature molten salt tank (8); The heat of the first heater is from electric heating, high-temperature flue gas, steam or waste heat recovery.

8. The molten salt-based thermal energy storage- based carbon dioxide power generation system of claim 1, wherein, A second heat exchanger (10) and a low-temperature molten salt tank (11) are further arranged; The heat release end inlet of the second heat exchanger (10) is in communication with the medium-temperature molten salt tank (7), and the heat release end outlet of the second heat exchanger (10) is in communication with the low-temperature molten salt tank (11). The heat-absorbing end inlet of the second heat exchanger (10) is communicated with the carbon dioxide outlet of the carbon dioxide compressor (1), and the heat-absorbing end outlet of the second heat exchanger (10) is communicated with the carbon dioxide inlet of the high-speed turbine (2), for heating a part of the critical carbon dioxide produced by the carbon dioxide compressor (1) by using the heat of the molten salt in the medium-temperature molten salt tank (7) and providing the high-speed turbine (2).

9. The molten salt-based thermal energy storage- based carbon dioxide power generation system according to claim 8, characterized by, A medium-temperature molten salt pump (12) is arranged between the medium-temperature molten salt tank (7) and the heat-releasing end inlet of the second heat exchanger (10).

10. The molten salt-based thermal energy storage- based carbon dioxide power generation system according to claim 9, characterized by, A second heater is further included, one end of which is connected with the low-temperature molten salt tank (11), and the other end of which is connected with the medium-temperature molten salt tank (7) and the high-temperature molten salt tank (8) respectively, for storing the low-temperature molten salt in the low-temperature molten salt tank (11) to the medium-temperature molten salt tank (7) or the high-temperature molten salt tank (8) after heating; The heat of the second heater comes from electric heating, high-temperature flue gas, steam or waste heat recovery.

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