A gas supplement heat storage power generation system

Abstract

A gas heat supplement and heat storage power generation system comprises a low-temperature energy storage system, a high-temperature energy storage system, a molten salt energy storage device, a counterflow heat exchanger, a compressor, an expander, a generator, a boiler combustion heating system and connecting pipelines therebetween; the boiler combustion heating system comprises a combustion chamber and a boiler heating system in communication with the combustion chamber; the boiler heating system mainly comprises a heating module, and a heat absorption pipeline is arranged in the heating module; the expander and the heat absorption pipeline are connected in series and are connected in parallel with the compressor branch between one end of a steam passage of the counterflow heat exchanger and a port A of the low-temperature energy storage system; the other end of the steam passage of the counterflow heat exchanger is in communication with a port B of the high-temperature energy storage system; and both ends of a molten salt passage of the counterflow heat exchanger are in communication with the molten salt energy storage device. The design of the boiler heating system is added, the power generation efficiency is improved, and the commercial implementation is easy.

Description

Technical Field

[0001] This invention belongs to the field of energy storage and power generation technology in new energy, and specifically relates to a gas-fired thermal storage and power generation system. Background Technology

[0002] Energy storage technology is a key technology for solving the problems of large-scale integration of renewable energy and curtailment of wind and solar power; it is an essential technology for the development of distributed energy, smart grids, and the energy internet; and it is also an important supporting technology for solving peak shaving and valley filling of conventional power, improving the efficiency, security, and economy of conventional energy generation and transmission. As green energy begins to gradually replace global electricity supply, large-scale energy storage will be needed all over the world, and new technologies such as carbon dioxide energy storage, compressed air energy storage, and hydrogen energy storage are emerging one after another.

[0003] Compressed air energy storage boasts a large capacity, with single-unit capacities exceeding hundreds of megawatts, second only to pumped hydro storage. However, the compressed air used for energy storage is heated, leading to energy loss during the conversion process and low energy utilization efficiency. It has not yet been commercialized and is heavily limited by geographical conditions. To address the technical and application bottlenecks of compressed air energy storage systems, carbon dioxide energy storage is proposed. Compared to air, carbon dioxide offers unique advantages as a medium; however, its cost is high, and the main equipment is still in the research stage, requiring extensive research and development to make it more feasible. Hydrogen energy storage faces challenges due to high hydrogen costs, high power plant construction costs, low energy conversion efficiency, low technological maturity, and a long process from hydrogen production to storage, transportation, and power generation. These factors pose significant challenges to the widespread application of hydrogen energy storage power generation. Therefore, finding a new energy storage power generation technology solution is essential. Summary of the Invention

[0004] To achieve low-cost, high-efficiency energy storage, this invention provides a gas-fired thermal energy storage power generation system. Compared to existing technologies, it uses steam as the working medium and molten salt as the thermal storage medium. Through the design of high and low temperature energy storage systems, it achieves phase change thermal energy storage and extraction, improving energy storage power generation efficiency. In particular, the design of adding a boiler heating system before the expander further improves power generation efficiency and is easy to commercially implement. The specific description is as follows:

[0005] A gas-fired thermal energy storage and power generation system includes a cryogenic energy storage system, a high-temperature energy storage system, a molten salt energy storage device, a countercurrent heat exchanger, a compressor, an expander, a generator, a boiler combustion heating system, and connecting pipelines between them. The compressor inlet and the expander outlet are both connected to port A of the cryogenic energy storage system. The boiler combustion heating system includes a combustion chamber and a boiler heating system connected to the combustion chamber. The boiler heating system mainly includes a heating module, which contains a heat absorption pipe. Port C of the heat absorption pipe is connected to the expander inlet. Port D of the heat absorption pipe is connected to one end of the steam passage of the countercurrent heat exchanger, and the compressor outlet is also connected to this end of the steam passage of the countercurrent heat exchanger. The other end of the steam passage of the countercurrent heat exchanger is connected to port B of the high-temperature energy storage system. Both ends of the molten salt passage of the countercurrent heat exchanger are connected to the molten salt energy storage device. The expander is connected to the generator.

[0006] Furthermore, the gas-fired thermal energy storage power generation system also includes a heat dissipation device, which is installed between the outlet of the expander and port A of the cryogenic energy storage system.

[0007] Furthermore, the cryogenic energy storage system mainly includes a cryogenic hot water tank and two solenoid valves; a diverter is provided near the bottom of the cryogenic hot water tank, and a diversion port is provided on the top of the diverter; the outlet of the cryogenic hot water tank is connected to port A of the cryogenic energy storage system through a first solenoid valve; the diverter of the cryogenic hot water tank is connected to port A of the cryogenic energy storage system through a second solenoid valve; port A of the cryogenic energy storage system is connected to the compressor inlet and the expander outlet respectively.

[0008] Furthermore, the high-temperature energy storage system includes a high-temperature hot water tank and two solenoid valves; a diverter is provided at the bottom of the high-temperature hot water tank, and a diversion port is provided on the top of the diverter; the outlet of the high-temperature hot water tank is connected to port B of the high-temperature energy storage system through a third solenoid valve, the diverter inside the high-temperature hot water tank is connected to port B of the high-temperature energy storage system through a fourth solenoid valve, and port B of the high-temperature energy storage system is connected to the steam channel of the counter-current heat exchanger.

[0009] Furthermore, the cryogenic energy storage system includes a cryogenic hot water tank, a cryogenic phase change heat storage tank, a first water pump, a third check valve, and connecting pipelines between them; the cryogenic phase change heat storage tank contains cryogenic phase change material, and heat transfer pipes are arranged around the cryogenic phase change material; one end of the heat transfer pipe inside the cryogenic phase change heat storage tank is connected to port A of the cryogenic energy storage system, and port A of the cryogenic energy storage system is connected to the inlet of the compressor and the outlet of the expander respectively; the first water pump and the third check valve are connected in parallel between the heat transfer pipe of the cryogenic phase change heat storage tank and the cryogenic hot water tank.

[0010] Furthermore, the high-temperature energy storage system includes a high-temperature hot water tank, a high-temperature phase change heat storage tank, a second water pump, a fourth check valve, and connecting pipelines between them; the high-temperature phase change heat storage tank contains high-temperature phase change material, and heat transfer pipes are arranged around the high-temperature phase change material; one end of the heat transfer pipe inside the high-temperature phase change heat storage tank is connected to port B of the high-temperature energy storage system, and port B of the high-temperature energy storage system is connected to the steam channel of the countercurrent heat exchanger; the outlets of the second water pump and the fourth check valve are connected to the high-temperature hot water tank 2, and the fourth check valve is connected in parallel between the heat transfer pipe of the high-temperature phase change heat storage tank and the high-temperature hot water tank.

[0011] Furthermore, the molten salt energy storage device includes a high-temperature molten salt tank, a low-temperature molten salt tank, a first molten salt pump, a second molten salt pump, a first one-way valve, a second one-way valve, and connecting pipelines between them; the first molten salt pump and the first one-way valve are connected in parallel between the high-temperature molten salt tank and the molten salt channel of the countercurrent heat exchanger; the second molten salt pump and the second one-way valve are connected in parallel between the low-temperature molten salt tank and the molten salt channel of the countercurrent heat exchanger.

[0012] Furthermore, the molten salt energy storage device includes a high-temperature molten salt tank, a low-temperature molten salt tank, a four-way valve, a second molten salt pump, and connecting pipelines between them; the high-temperature molten salt tank is directly connected to the molten salt channel in the countercurrent heat exchanger, and the four-way valve and the second molten salt pump are installed between the low-temperature molten salt tank and the countercurrent heat exchanger.

[0013] Furthermore, the compressor is a variable frequency compressor; the expander is a variable frequency expander.

[0014] Furthermore, the combustion chamber of the boiler, which is used for combustion heating, burns natural gas or coal.

[0015] Furthermore, one or more of the first check valve, the second check valve, the third check valve, and the fourth check valve can be replaced by an electric valve or a solenoid valve.

[0016] The gas-fired thermal energy storage power generation system of the present invention uses steam as the working medium and liquid molten salt as the thermal storage medium. By designing high and low temperature energy storage systems, and adding variable frequency compressors and variable frequency expanders to operate under different conditions according to working needs, phase change thermal energy storage and extraction are realized. In particular, the design of adding a boiler heating system in front of the expander further improves the power generation efficiency. This system not only improves working efficiency, but is also easy to implement commercially. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Appendix Figure 1 This is a schematic diagram of the first structure of the gas-fired thermal storage power generation system of the present invention.

[0019] Appendix Figure 2 This is a schematic diagram of the second structure of the gas-fired thermal storage power generation system of the present invention.

[0020] Appendix Figure 3 This is a schematic diagram of the third structure of the gas-fired thermal storage power generation system of the present invention.

[0021] Appendix Figure 4 This is a schematic diagram of the fourth structure of the gas-fired thermal storage power generation system of the present invention.

[0022] In the diagram: 100, Low-temperature energy storage system; 1, Low-temperature hot water tank; 200, High-temperature energy storage system; 2, High-temperature hot water tank; 3, High-temperature molten salt tank; 4, Low-temperature molten salt tank; 5, Countercurrent heat exchanger; 6, Compressor; 7, Expander; 8, Generator; 91, First molten salt pump; 92, Second molten salt pump; 101-104, One-way valve; 105, Four-way valve; 111-114, Solenoid valve; 12, Heat release valve; 131-132, Flow divider; 14, Boiler heating system; 141, Heating module; 142, Heat absorption pipe; 151, Low-temperature phase change thermal storage tank; 152, High-temperature phase change thermal storage tank; 161, First water pump; 162, Second water pump; 17, Heat dissipation equipment. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below.

[0024] Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0025] Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. To facilitate understanding of the embodiments, various embodiments or implementation methods are provided below to illustrate the relevant devices, modules, and functions of this invention.

[0026] As attached Figure 1As shown, a gas-fired thermal energy storage power generation system includes a low-temperature energy storage system 100, a high-temperature energy storage system 200, a molten salt energy storage device, a countercurrent heat exchanger 5, a compressor 6, an expander 7, a generator 8, a boiler combustion heating system, and connecting pipelines between them. The inlet of the compressor 6 and the outlet of the expander 7 are both connected to port A of the low-temperature energy storage system 100; the boiler combustion heating system includes a combustion chamber and a boiler heating system 14 connected to the combustion chamber; the boiler heating system 14 mainly includes a heating module 141, and the heating module 141 is provided with a heat absorption pipe 142; port C of the heat absorption pipe 142 is connected to the inlet of the expander 7; port D of the heat absorption pipe 142 is connected to one end of the steam passage of the countercurrent heat exchanger 5, and the outlet of the compressor 6 is also connected to this end of the steam passage of the countercurrent heat exchanger 5; the other end of the steam passage of the countercurrent heat exchanger 5 is connected to port B of the high-temperature energy storage system 200; both ends of the molten salt passage of the countercurrent heat exchanger 5 are connected to the molten salt energy storage device; the expander 7 is connected to the generator 8.

[0027] The gas-fired thermal energy storage power generation system described above also includes a heat dissipation device 17, which is installed between the outlet of the expander 7 and port A of the cryogenic energy storage system 100. The heat dissipation device is one of an air-cooled heat dissipation device, a cooling tower, or a plate heat exchanger for heat recovery. In this way, the medium-temperature steam after the expander 7 has done work is cooled by the heat dissipation device 17 and becomes low-temperature steam before entering the cryogenic energy storage system 100.

[0028] The heat dissipation device 17 described above is used in a heat recovery plate heat exchanger, where the recovered heat is used for heating, hot water supply, or industrial steam supply.

[0029] The compressor 6 is a variable frequency compressor; the expander 7 is a variable frequency expander.

[0030] The combustion chamber of the boiler, which is heated by combustion, burns either natural gas or coal. Specific Implementation Method 1

[0032] As attached Figure 1As shown, the cryogenic energy storage system 100 mainly includes a cryogenic hot water tank 1 and two solenoid valves 111-112. A distributor 131 is located near the bottom of the cryogenic hot water tank 1, with a diversion port on its top. The function of the distributor 131 is to divert the cryogenic steam medium entering the cryogenic hot water tank 1 through the distributor 131, and then allow it to enter the bottom of the cryogenic hot water tank 1 through the diversion port. The cryogenic steam medium rises from the bottom of the cryogenic hot water tank 1, exchanging heat with the hot water in the tank. During this heat exchange, the cryogenic steam medium undergoes a phase change, becoming cryogenic hot water. The hot water in the cryogenic hot water tank 1 absorbs the heat from the cryogenic steam medium, causing its temperature to rise. The outlet of the cryogenic hot water tank 1 is connected to port A of the cryogenic energy storage system 100 through the first solenoid valve 111; the distributor 131 of the cryogenic hot water tank 1 is connected to port A of the cryogenic energy storage system 100 through the second solenoid valve 112; and port A of the cryogenic energy storage system 100 is connected to the inlet of the compressor 6 and the outlet of the expander 7, respectively.

[0033] The molten salt energy storage device includes a high-temperature molten salt tank 3, a low-temperature molten salt tank 4, a first molten salt pump 91, a second molten salt pump 92, a first one-way valve 101, a second one-way valve 102, and connecting pipelines between them. The first molten salt pump 91 and the first one-way valve 101 are connected in parallel between the high-temperature molten salt tank 3 and the molten salt channel of the countercurrent heat exchanger 5. The second molten salt pump 92 and the second one-way valve 102 are connected in parallel between the low-temperature molten salt tank 4 and the molten salt channel of the countercurrent heat exchanger 5. The high-temperature molten salt tank 3 and the low-temperature molten salt tank 4 are installed below the countercurrent heat exchanger 5, forming a certain height difference. When the molten salt energy storage device stores heat, the second molten salt pump 92 draws molten salt from the low-temperature molten salt tank 4 and sends it into the molten salt channel of the countercurrent heat exchanger 5. The low-temperature molten salt absorbs heat from the heat transfer medium in another channel of the countercurrent heat exchanger 5 and becomes high-temperature molten salt. Then, the high-temperature molten salt returns to the high-temperature molten salt tank 3 by gravity through the first one-way valve 101. When the molten salt energy storage device releases heat, the first molten salt pump 91 draws molten salt from the high-temperature molten salt tank 3. The high-temperature molten salt is sent into the molten salt channel of the countercurrent heat exchanger 5. The high-temperature molten salt exchanges heat with the heat transfer medium in another channel of the countercurrent heat exchanger 5 and becomes low-temperature molten salt. Then, the low-temperature molten salt returns to the low-temperature molten salt tank 4 by gravity through the second one-way valve 102.

[0034] The high-temperature energy storage system 200 includes a high-temperature hot water tank 2 and two solenoid valves 113-114. A diverter 132 is located at the bottom of the high-temperature hot water tank 2, with a diversion port on its top. The function of the diverter 132 is to divert the high-temperature steam medium entering the high-temperature hot water tank 2 through the diverter 132, and then allow it to enter the bottom of the tank through the diversion port on the diverter 131. The high-temperature steam medium rises from the bottom of the tank and exchanges heat with the medium-temperature hot water in the tank. During this heat exchange, the high-temperature steam medium undergoes a phase change, becoming high-temperature hot water. The medium-temperature hot water in the tank absorbs the heat from the high-temperature steam medium, also becoming high-temperature hot water. The outlet of the high-temperature hot water tank 2 is connected to port B of the high-temperature energy storage system 200 via a third solenoid valve 113. The diverter 132 inside the high-temperature hot water tank 2 is connected to port B of the high-temperature energy storage system 200 via a fourth solenoid valve 114. Port B of the high-temperature energy storage system 200 is connected to the steam channel of the counter-current heat exchanger 5.

[0035] The gas-fired thermal storage power generation system of this invention has two working modes: thermal storage working mode and power generation working mode.

[0036] In thermal storage mode: the first solenoid valve 111, the fourth solenoid valve 114, the compressor 6, and the second molten salt pump 92 are activated; the second solenoid valve 112, the third solenoid valve 113, the expander 7, and the first molten salt pump 91 are closed. Specifically, under the action of the compressor 6, the low-temperature hot water in the low-temperature hot water tank 1 is released through the first solenoid valve 111, undergoing a phase change to become low-temperature steam. This low-temperature steam then enters the compressor 6 and is compressed into high-temperature, high-pressure superheated steam. This high-temperature, high-pressure superheated steam enters the steam channel of the counter-current heat exchanger 5. Simultaneously, the second molten salt pump 92 draws low-temperature molten salt from the low-temperature molten salt tank 4 and sends it into the molten salt channel of the counter-current heat exchanger 5. The low-temperature molten salt absorbs the heat from the high-temperature, high-pressure superheated steam in the steam channel of the counter-current heat exchanger 5 and becomes high-temperature molten salt. Then, the high-temperature molten salt is subjected to heavy... The force acts on the first one-way valve 101 and returns to the high-temperature molten salt tank 3; while the high-temperature and high-pressure superheated steam in the steam channel of the counter-current heat exchanger 5 becomes high-temperature and high-pressure steam after quantitative heat release. Then, the high-temperature and high-pressure steam enters the high-temperature hot water tank 2 through the fourth solenoid valve 114 and enters the bottom of the high-temperature hot water tank 2 through the diversion port on the diversion device 131. The high-temperature and high-pressure steam medium moves upward from the bottom of the high-temperature hot water tank 2 and exchanges heat with the medium-temperature and high-pressure hot water in the high-temperature hot water tank 2. The high-temperature and high-pressure steam medium undergoes a phase change during the heat exchange and becomes high-temperature and high-pressure hot water. The medium-temperature and high-pressure hot water in the high-temperature hot water tank 2 absorbs the heat of the high-temperature and high-pressure steam medium and becomes high-temperature and high-pressure hot water. Finally, the heat is stored in the high-temperature hot water tank 2 in the form of high-temperature and high-pressure hot water, thus completing the heat storage working mode.

[0037] In power generation mode: the first solenoid valve 111, the fourth solenoid valve 114, the compressor 6, and the second molten salt pump 92 are closed; the second solenoid valve 112, the third solenoid valve 113, the expander 7, and the first molten salt pump 91 are open. Specifically, when the fourth solenoid valve 114 is opened, the high-temperature, high-pressure hot water in the high-temperature hot water tank 2 undergoes a phase change, becoming high-temperature, high-pressure steam. This high-temperature, high-pressure steam enters the steam channel of the counter-current heat exchanger 5. Simultaneously, the first molten salt pump 91 draws high-temperature molten salt from the high-temperature molten salt tank 3 and sends it into the molten salt channel of the counter-current heat exchanger 5. The high-temperature, high-pressure steam and the high-temperature molten salt exchange heat in the counter-current heat exchanger 5, causing the high-temperature molten salt to release heat and become low-temperature molten salt. The low-temperature molten salt returns to the low-temperature molten salt tank 4 in the counter-current heat exchanger 5 by gravity through the second one-way valve 102. Simultaneously, the high-temperature, high-pressure steam absorbs heat from the high-temperature molten salt, undergoing a first temperature increase. The heated high-temperature, high-pressure steam then enters the boiler... The heat absorption pipe 142 of the thermal system 14 absorbs the heat released from the combustion chamber, raising its temperature again. Finally, it enters the expander 7 to do work, converting thermal energy into mechanical energy to drive the generator 8 to generate electricity, ultimately realizing the conversion of thermal energy into electrical energy output. The steam after doing work is discharged through the expander 7, becoming medium-temperature steam. Then, the medium-temperature steam enters the heat dissipation device 17 for cooling, becoming low-temperature steam. The low-temperature steam medium enters the distributor 131 inside the low-temperature hot water tank 1 through the second solenoid valve 112 for diversion, and then enters the bottom of the low-temperature hot water tank 1 through the diversion port on the distributor 131. The low-temperature steam medium moves upward from the bottom of the low-temperature hot water tank 1, exchanging heat with the hot water in the low-temperature hot water tank 1. The low-temperature steam medium undergoes a phase change during the heat exchange, becoming low-temperature hot water. The hot water in the low-temperature hot water tank 1 absorbs the heat of the low-temperature steam medium, and its temperature rises slightly. Finally, the low-temperature hot water is stored in the low-temperature hot water tank 1, thus completing the power generation working mode.

[0038] In the power generation operating modes described above, apart from a boiler heating system, all other processes that share pipelines and equipment with the thermal storage operating mode are reversible. Specific Implementation Method Two

[0040] like Figure 2 As shown, compared with Example 1 Figure 1In contrast, the molten salt energy storage device in the gas-fired thermal energy storage power generation system of the present invention includes a high-temperature molten salt tank 3, a low-temperature molten salt tank 4, a four-way valve 105, a second molten salt pump 92, and connecting pipelines between them. The high-temperature molten salt tank 3 is directly connected to the molten salt channel in the counter-current heat exchanger 5. The low-temperature molten salt tank 4 is connected to the counter-current heat exchanger 5 by the four-way valve 105 and the second molten salt pump 92. The connections of other components are the same as in Embodiment 1. When the molten salt energy storage device stores heat, under the action of the second molten salt pump 92, the molten salt in the low-temperature molten salt tank 4 enters the second molten salt pump 92 through the four-way valve 105, and then is sent to the molten salt channel of the counter-current heat exchanger 5 again through the four-way valve 105. The low-temperature molten salt absorbs the heat of the high-temperature and high-pressure superheated steam in the counter-current heat exchanger 5 and becomes high-temperature molten salt. Then the high-temperature molten salt directly returns to the high-temperature molten salt tank 3. When the molten salt energy storage device releases heat, under the action of the second molten salt pump 92, the high-temperature molten salt in the high-temperature molten salt tank 3 is sent into the molten salt channel of the counter-current heat exchanger 5. The high-temperature molten salt exchanges heat with the high-temperature and high-pressure steam of the counter-current heat exchanger 5. The high-temperature and high-pressure steam absorbs heat and becomes superheated steam, while the high-temperature molten salt releases heat and becomes low-temperature molten salt. Then, the low-temperature molten salt returns to the low-temperature molten salt tank 4 through the four-way valve 105 and the second molten salt pump 92. The installation positions of the high-temperature molten salt tank 3 and the low-temperature molten salt tank 4 are not restricted. Figure 2 The working principle of the other components in the gas-fired thermal energy storage power generation system shown is the same as that in Embodiment 1, except for the molten salt energy storage device. Specific Implementation Method 3

[0042] As attached Figure 3 As shown, compared with the appendix in Example 1 Figure 1 In comparison, apart from the different internal structures of the cryogenic energy storage system 100 and the high-temperature energy storage system 200, the installation and operation principles of other components are the same as in Example 1.

[0043] In the appendix Figure 3 The cryogenic energy storage system 100 includes a cryogenic hot water tank 1, a cryogenic phase change heat storage tank 151, a first water pump 161, a third one-way valve 103, and connecting pipelines between them. The cryogenic phase change heat storage tank 151 contains cryogenic phase change material, and heat transfer pipes are arranged around the cryogenic phase change material. The inlet of the first water pump 161 is connected to the cryogenic hot water tank 1, and the outlet of the first water pump 161 is connected to the heat transfer pipes inside the cryogenic phase change heat storage tank 151. The inlet of the third one-way valve 103 is connected to the heat transfer pipes inside the cryogenic phase change heat storage tank 151, and the outlet of the third one-way valve 103 is connected to the cryogenic hot water tank 1. The other end of the heat transfer pipes inside the cryogenic phase change heat storage tank 151 is connected to port A of the cryogenic energy storage system 100, and port A of the cryogenic energy storage system 100 is connected to the inlet of the compressor 6 and the outlet of the expander 7, respectively.

[0044] The high-temperature energy storage system 200 includes a high-temperature hot water tank 2, a high-temperature phase change heat storage tank 152, a second water pump 162, a fourth one-way valve 104, and connecting pipelines between them. The high-temperature phase change heat storage tank 152 contains high-temperature phase change material, and heat transfer pipes are arranged around the high-temperature phase change material. The inlet of the second water pump 162 is connected to the high-temperature hot water tank 2, and the outlet of the second water pump 162 is connected to the heat transfer pipes inside the high-temperature phase change heat storage tank 152. The outlet of the fourth one-way valve 104 is connected to the high-temperature hot water tank 2, and the inlet of the fourth one-way valve 104 is connected to the heat transfer pipes inside the high-temperature phase change heat storage tank 152. The other end of the heat transfer pipes inside the high-temperature phase change heat storage tank 152 is connected to port B of the high-temperature energy storage system 200, and port B of the high-temperature energy storage system 200 is connected to the steam channel of the counter-current heat exchanger 5.

[0045] The gas-fired thermal storage power generation system of this invention has two working modes: thermal storage working mode and power generation working mode.

[0046] In thermal storage mode: the first water pump 161, compressor 6, and second molten salt pump 92 are activated, while the second water pump 162, expander 7, and first molten salt pump 91 are deactivated. Specifically, the first water pump 161 draws low-temperature hot water from the low-temperature hot water tank 1 and sends it to the low-temperature phase change thermal storage tank 151. The low-temperature hot water undergoes isothermal heat exchange with the low-temperature phase change material in the low-temperature phase change thermal storage tank 151. The low-temperature hot water absorbs heat from the low-temperature phase change material and becomes low-temperature, low-pressure steam. This low-temperature, low-pressure steam enters the compressor 6 and is compressed into high-temperature, high-pressure superheated steam. The high-temperature, high-pressure superheated steam enters the steam channel of the counter-current heat exchanger 5. Simultaneously, the second molten salt pump 92 draws low-temperature molten salt from the low-temperature molten salt tank 4. The molten salt is fed into the molten salt channel of the counter-current heat exchanger 5. The low-temperature molten salt absorbs the heat from the high-temperature and high-pressure superheated steam in the steam channel of the counter-current heat exchanger 5 and becomes high-temperature molten salt. Then, the high-temperature molten salt returns to the high-temperature molten salt tank 3 by gravity through the first one-way valve 101. Meanwhile, the high-temperature and high-pressure superheated steam in the steam channel of the counter-current heat exchanger 5 releases heat and becomes high-temperature and high-pressure steam. Then, the high-temperature and high-pressure steam enters the high-temperature phase change heat storage tank 152 and undergoes isothermal phase change with the high-temperature phase change material in the high-temperature phase change heat storage tank 152. The high-temperature and high-pressure steam undergoes isothermal phase change and becomes high-temperature and high-pressure hot water. Finally, the high-temperature and high-pressure hot water is sent to the high-temperature hot water tank 2 through the fourth one-way valve 104 to store the heat. This completes the heat storage working mode.

[0047] In power generation mode: the first water pump 161, compressor 6, and second molten salt pump 92 are shut down, while the second water pump 162, expander 7, and first molten salt pump 91 are turned on. Specifically, the second water pump 162 draws high-temperature, high-pressure hot water from the high-temperature hot water tank 2 and sends it to the high-temperature phase change heat storage tank 152. The high-temperature, high-pressure hot water absorbs heat from the high-temperature phase change material in the high-temperature phase change heat storage tank 152 and becomes high-temperature, high-pressure steam. This high-temperature, high-pressure steam enters the steam channel of the counter-current heat exchanger 5. Simultaneously, the first molten salt pump 91 draws high-temperature molten salt from the high-temperature molten salt tank 3 and sends it to the molten salt channel of the counter-current heat exchanger 5. The high-temperature, high-pressure steam and the high-temperature molten salt exchange heat in the counter-current heat exchanger 5, causing the high-temperature molten salt to release heat and become low-temperature molten salt. The low-temperature molten salt then passes through the counter-current heat exchanger 5 by gravity. The force acts on the steam, which returns to the low-temperature molten salt tank 4 via the second one-way valve 102. Simultaneously, the high-temperature and high-pressure steam absorbs the heat from the high-temperature molten salt, undergoing a first temperature increase. The heated high-temperature and high-pressure steam then enters the heat absorption pipe 142 of the boiler heating system 14 to absorb the heat released from the combustion chamber, raising the temperature again. Finally, it enters the expander 7 to perform work, converting thermal energy into mechanical energy to drive the generator 8 to generate electricity, ultimately achieving the conversion of thermal energy into electrical energy output. The steam after performing work is discharged through the expander 7, becoming medium-temperature steam. Subsequently, the medium-temperature steam enters the heat dissipation device 17 for cooling, becoming low-temperature steam. The low-temperature steam medium enters the low-temperature phase change heat storage tank 151 to exchange heat with the low-temperature phase change material. The low-pressure water vapor undergoes isothermal heat release, becoming low-temperature hot water, which is stored in the low-temperature hot water tank 1 via the third one-way valve 103.

[0048] The phase change material in the low-temperature phase change thermal storage tank 151 is a low-temperature solid-liquid phase change material. In the thermal storage working mode, the low-temperature phase change material releases heat isothermally and changes from liquid to solid. In the power generation working mode, the low-temperature phase change material absorbs heat isothermally and changes from solid to liquid.

[0049] The phase change material in the high-temperature phase change thermal storage tank 5 is a high-temperature solid-liquid phase change material. In the thermal storage working mode, the high-temperature phase change material absorbs heat isothermally and changes from solid to liquid. In the power generation working mode, the high-temperature phase change material releases heat isothermally and changes from liquid to solid. Specific Implementation Method Four

[0051] like Figure 4 As shown, compared with Example 3 Figure 3In contrast, the molten salt energy storage device in the gas-fired thermal energy storage power generation system of the present invention includes a high-temperature molten salt tank 3, a low-temperature molten salt tank 4, a four-way valve 105, a second molten salt pump 92, and connecting pipelines between them. The high-temperature molten salt tank 3 is directly connected to the molten salt channel in the counter-current heat exchanger 5. The low-temperature molten salt tank 4 is connected to the counter-current heat exchanger 5 by the four-way valve 105 and the second molten salt pump 92. The connections of other components are the same as in Embodiment 3. When the molten salt energy storage device stores heat, under the action of the second molten salt pump 92, the molten salt in the low-temperature molten salt tank 4 enters the second molten salt pump 92 through the four-way valve 105, and then is sent to the molten salt channel of the counter-current heat exchanger 5 again through the four-way valve 105. The low-temperature molten salt absorbs the heat of the high-temperature and high-pressure superheated steam in the counter-current heat exchanger 5 and becomes high-temperature molten salt. Then the high-temperature molten salt directly returns to the high-temperature molten salt tank 3. When the molten salt energy storage device releases heat, under the action of the second molten salt pump 92, the high-temperature molten salt in the high-temperature molten salt tank 3 is sent into the molten salt channel of the counter-current heat exchanger 5. The high-temperature molten salt exchanges heat with the high-temperature and high-pressure steam of the counter-current heat exchanger 5. The high-temperature and high-pressure steam absorbs heat and becomes superheated steam, while the high-temperature molten salt releases heat and becomes low-temperature molten salt. Then, the low-temperature molten salt returns to the low-temperature molten salt tank 4 through the four-way valve 105 and the second molten salt pump 92. The installation positions of the high-temperature molten salt tank 3 and the low-temperature molten salt tank 4 are not restricted. Figure 4 The working principle of the other components in the gas-fired thermal energy storage power generation system shown is the same as that in Embodiment 3, except for the molten salt energy storage device.

[0052] In the above four embodiments, apart from a boiler heating system, the processes that share pipelines and equipment with the thermal storage working mode in the power generation working mode are all reversible.

[0053] The first check valve 101, the second check valve 102, the third check valve 103 and the fourth check valve 104 can be replaced by solenoid valves.

[0054] The low-temperature hot water tank 1 is also connected to a heat release valve 12, which is connected to a place that requires low-quality heat. In this way, the hot water in the low-temperature hot water tank 1 can be used for different places such as low-temperature low-pressure power generation, winter heating or industrial hot water.

Claims

1. A gas-fired thermal energy storage power generation system, characterized in that, The system includes a cryogenic energy storage system, a high-temperature energy storage system, a molten salt energy storage device, a counter-current heat exchanger, a compressor, an expander, a generator, a boiler combustion heating system, and connecting pipelines between them. The cryogenic energy storage system includes a cryogenic hot water tank, a cryogenic phase change heat storage tank, and connecting pipelines between them. The cryogenic phase change heat storage tank contains cryogenic phase change material, and heat transfer pipes are arranged around the cryogenic phase change material. One end of the heat transfer pipe inside the cryogenic phase change heat storage tank is connected to port A of the cryogenic energy storage system, and the other end of the heat transfer pipe inside the cryogenic phase change heat storage tank is connected to the cryogenic hot water tank. Port A of the cryogenic energy storage system is connected to the inlet of the compressor and the outlet of the expander. The boiler combustion heating system includes a combustion chamber and a boiler heating system connected to the combustion chamber. The boiler heating system mainly includes a heating module, and the heating module contains a heat absorption pipe. Port C of the heat absorption pipe is connected to the inlet of the expander. Port D of the heat absorption pipe... The compressor outlet is also connected to the same end of the steam passage of the counter-current heat exchanger. The high-temperature energy storage system includes a high-temperature hot water tank, a high-temperature phase change heat storage tank, and connecting pipes between them. The high-temperature phase change heat storage tank contains high-temperature phase change material, and heat transfer pipes are arranged around the high-temperature phase change material. One end of the heat transfer pipe inside the high-temperature phase change heat storage tank is connected to port B of the high-temperature energy storage system, and the other end of the heat transfer pipe inside the high-temperature phase change heat storage tank is connected to the high-temperature hot water tank. Port B of the high-temperature energy storage system is connected to the other end of the steam passage of the counter-current heat exchanger. Both ends of the molten salt passage of the counter-current heat exchanger are connected to the molten salt energy storage device. The molten salt energy storage device includes a high-temperature molten salt tank, a low-temperature molten salt tank, a first molten salt pump, a second molten salt pump, a first one-way valve, a second one-way valve, and connecting pipes between them. The first molten salt pump and the second one-way valve... A one-way valve is connected in parallel between the high-temperature molten salt tank and the molten salt channel of the countercurrent heat exchanger; the second molten salt pump and the second one-way valve are connected in parallel between the low-temperature molten salt tank and the molten salt channel of the countercurrent heat exchanger; the expander is connected to the generator.

2. The gas-fired thermal energy storage power generation system as described in claim 1, characterized in that, The gas-fired thermal energy storage power generation system also includes a heat dissipation device, which is installed between the outlet of the expander and port A of the cryogenic energy storage system.

3. The gas-fired thermal energy storage power generation system as described in claim 1, characterized in that, The cryogenic energy storage system mainly includes a cryogenic hot water tank and two solenoid valves; a diverter is provided near the bottom of the cryogenic hot water tank, and a diversion port is provided on the top of the diverter; the outlet of the cryogenic hot water tank is connected to port A of the cryogenic energy storage system through a first solenoid valve; the diverter of the cryogenic hot water tank is connected to port A of the cryogenic energy storage system through a second solenoid valve; port A of the cryogenic energy storage system is connected to the compressor inlet and the expander outlet respectively.

4. The gas-fired thermal energy storage power generation system as described in claim 1, characterized in that, The high-temperature energy storage system includes a high-temperature hot water tank and two solenoid valves; a diverter is provided at the bottom of the high-temperature hot water tank, and a diversion port is provided on the top of the diverter; the outlet of the high-temperature hot water tank is connected to port B of the high-temperature energy storage system through a third solenoid valve, the diverter inside the high-temperature hot water tank is connected to port B of the high-temperature energy storage system through a fourth solenoid valve, and port B of the high-temperature energy storage system is connected to the steam channel of the counter-current heat exchanger.

5. The gas-fired thermal energy storage power generation system as described in claim 1, characterized in that, The cryogenic energy storage system also includes a first water pump and a third check valve; the first water pump and the third check valve are connected in parallel between the heat transfer pipe of the cryogenic phase change thermal storage tank and the cryogenic hot water tank.

6. The gas-fired thermal energy storage power generation system as described in claim 1, characterized in that, The high-temperature energy storage system also includes a second water pump and a fourth check valve; the second water pump and the fourth check valve are connected in parallel between the heat transfer pipe of the high-temperature phase change heat storage tank and the high-temperature hot water tank.

7. The gas-fired thermal energy storage power generation system as described in claim 1, characterized in that, The molten salt energy storage device includes a high-temperature molten salt tank, a low-temperature molten salt tank, a four-way valve, a second molten salt pump, and connecting pipelines between them; the high-temperature molten salt tank is directly connected to the molten salt channel in the countercurrent heat exchanger, and the four-way valve and the second molten salt pump are installed between the low-temperature molten salt tank and the countercurrent heat exchanger.

8. A gas-fired thermal energy storage power generation system as described in claim 1, characterized in that, The compressor is a variable frequency compressor; the expander is a variable frequency expander.

9. A gas-fired thermal energy storage power generation system as described in claim 1, characterized in that, The combustion chamber of the boiler is heated by burning natural gas or coal.

10. A gas-fired thermal energy storage power generation system as described in claim 1, characterized in that, One or more of the first check valve, the second check valve, the third check valve, and the fourth check valve may be replaced by an electric valve or a solenoid valve.

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