Steam medium phase change heat storage power generation system

Abstract

A steam medium phase change heat storage power generation system comprises a low-temperature phase change heat storage and heat transfer device, a fused salt energy storage device, a high-temperature phase change heat storage and heat transfer device, a compressor, an expansion machine, a power generator and connecting pipelines among the low-temperature phase change heat storage and heat transfer device, the fused salt energy storage device, the high-temperature phase change heat storage and heat transfer device, the compressor, the expansion machine and the power generator. The fused salt energy storage device is communicated with an outlet of the compressor and an inlet of the expansion machine, and the high-temperature phase change heat storage and transfer device is communicated with the fused salt energy storage device. Water vapor is adopted as a working medium, the phase change material and the liquid molten salt are adopted as heat storage media, phase change heat storage and phase change heat transfer are organically combined, and isothermal heat storage and isothermal heat energy storage and taking are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage and power generation of new energy, and in particular relates to a steam medium phase change heat storage and power generation system. Background Art

[0002] Energy storage technology is a key technology to solve the problems of large-scale access to renewable energy and wind and solar power abandonment; it is an essential technology for the development of distributed energy, smart grids, and energy Internet; it is also an important supporting technology to solve the problem of peak load shaving and valley filling of conventional electricity and improve the efficiency, safety, and economy of conventional energy generation and transmission. As green energy begins to gradually replace the global electricity supply, large-scale energy storage will be needed all over the world, and new technologies such as new carbon dioxide energy storage, compressed air energy storage, and hydrogen energy storage are emerging in an endless stream.

[0003] Among the new energy storage technologies, compressed air has a large energy storage capacity, and the capacity of a single unit can reach more than 100 megawatts, second only to pumped storage. However, the compressed air in the energy storage will be heated, resulting in energy loss in the conversion process. The energy utilization efficiency is low, and it has not been commercialized so far. At the same time, it is greatly restricted by geographical conditions. In view of the technical and application bottlenecks of the compressed air energy storage system, the carbon dioxide energy storage method is proposed. Compared with air, carbon dioxide has some unique advantages as a medium; however, its cost is relatively high, and the main equipment is still in the research stage. A lot of research and development is needed to make it more feasible. The pain points of hydrogen energy storage are high hydrogen cost, high power station cost, low energy conversion efficiency, low technology maturity, and a long process of hydrogen production-hydrogen storage-hydrogen transportation-power generation. Many factors have brought great challenges to the promotion of hydrogen energy storage power generation applications. Therefore, it is necessary to find a new energy storage technology solution. Summary of the invention

[0004] In order to achieve low-cost and high-efficiency energy storage, the present invention provides a steam medium phase change heat storage power generation system. Compared with the prior art, it combines phase change heat storage and phase change heat transfer to achieve isothermal heat storage and isothermal storage and access of heat energy, improves the efficiency of energy storage and power generation, and is easy to commercially implement. The specific description is as follows: A steam medium phase change heat storage power generation system, comprising a low-temperature phase change heat storage heat transfer device, a molten salt energy storage device, a high-temperature phase change heat storage heat transfer device, a compressor, an expander, a generator and connecting pipelines therebetween, wherein the expander is connected to the generator; The low-temperature phase-change heat storage and heat transfer device comprises a low-temperature hot water tank and a low-temperature phase-change heat storage tank; the low-temperature phase-change heat storage tank is filled with a low-temperature phase-change material, and a heat transfer pipe is arranged around the low-temperature phase-change material; one end of the heat transfer pipe of the low-temperature phase-change heat storage tank is connected to the low-temperature hot water tank; the other end of the heat transfer pipe of the low-temperature phase-change heat storage tank is respectively connected to the inlet of the compressor and the outlet of the expander; The molten salt energy storage device comprises a countercurrent heat exchanger, a high-temperature molten salt tank, a low-temperature molten salt tank and connecting pipelines therebetween; the steam channel of the countercurrent heat exchanger is connected to the outlet of the compressor and the inlet of the expander; the two ends of the molten salt channel of the countercurrent heat exchanger are connected to the high-temperature molten salt tank and the low-temperature molten salt tank respectively; The high-temperature phase-change heat storage and heat transfer device comprises a high-temperature hot water tank, a high-temperature phase-change heat storage tank and connecting pipes therebetween; the high-temperature phase-change heat storage tank is filled with a high-temperature phase-change material, and a heat transfer pipe is arranged around the high-temperature phase-change material; the high-temperature hot water tank is connected to the heat transfer pipe inside the high-temperature phase-change heat storage tank; the other end of the heat transfer pipe inside the high-temperature phase-change heat storage tank is connected to the steam channel of the countercurrent heat exchanger.

[0005] Furthermore, the molten salt energy storage device also includes a first molten salt pump, a second molten salt pump, a second one-way valve, a third one-way valve and connecting pipelines therebetween; the first molten salt pump and the second 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 third one-way valve are connected in parallel between the low-temperature molten salt tank and the molten salt channel of the countercurrent heat exchanger.

[0006] Furthermore, a first water pump and a first one-way valve are provided between the low-temperature hot water tank and the low-temperature phase change heat storage tank; the inlet of the first water pump is communicated with the low-temperature hot water tank, and the outlet of the first water pump is communicated with the heat transfer pipe inside the low-temperature phase change heat storage tank; the inlet of the first one-way valve is communicated with the heat transfer pipe inside the low-temperature phase change heat storage tank, and the outlet of the first one-way valve is communicated with the low-temperature hot water tank.

[0007] Furthermore, a second water pump and a fourth one-way valve are provided between the high-temperature hot water tank and the high-temperature phase-change heat storage tank; the inlet of the second water pump is communicated with the high-temperature hot water tank, and the outlet of the second water pump is communicated with the heat transfer pipe inside the high-temperature phase-change heat storage tank; the outlet of the fourth one-way valve is communicated with the high-temperature hot water tank, and the inlet of the fourth one-way valve is communicated with the heat transfer pipe inside the high-temperature phase-change heat storage tank; the other end of the heat transfer pipe inside the high-temperature phase-change heat storage tank is communicated with the steam channel of the countercurrent heat exchanger.

[0008] Furthermore, the molten salt energy storage device includes a countercurrent heat exchanger, a high-temperature molten salt tank, a low-temperature molten salt tank, a four-way valve, a second molten salt pump and connecting pipes therebetween; 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.

[0009] Furthermore, the phase change material in the low-temperature phase change heat storage tank is a low-temperature solid-liquid phase change material; and the phase change material in the high-temperature phase change heat storage tank is a high-temperature solid-liquid phase change material.

[0010] Furthermore, the low-temperature hot water tank is composed of a plurality of parallel low-temperature hot water tank groups, each of which is connected to a solenoid valve, and the start and stop of the corresponding low-temperature water storage tank is controlled by the solenoid valve; the high-temperature hot water tank is composed of a plurality of parallel high-temperature hot water tank groups, each of which is connected to a solenoid valve, and the start and stop of the corresponding high-temperature water storage tank is controlled by the solenoid valve;.

[0011] Furthermore, the low-temperature phase-change heat storage tank is composed of a plurality of groups of low-temperature phase-change heat storage tanks connected in parallel, and each low-temperature phase-change heat storage tank inlet and outlet are connected to a solenoid valve, and the start and stop of the corresponding low-temperature phase-change heat storage tank are controlled by the solenoid valve; the high-temperature phase-change heat storage tank is composed of a plurality of groups of high-temperature phase-change heat storage tanks connected in parallel, and each high-temperature phase-change heat storage tank inlet and outlet are connected to a solenoid valve, and the start and stop of the corresponding high-temperature phase-change heat storage tank are controlled by the solenoid valve.

[0012] Furthermore, the low-temperature molten salt tank is composed of a plurality of groups of low-temperature molten salt tanks connected in parallel, each of which is connected to a solenoid valve, and the start and stop of the corresponding low-temperature molten salt tank is controlled by the solenoid valve; the high-temperature molten salt tank is composed of a plurality of groups of high-temperature molten salt tanks connected in parallel, each of which is connected to a solenoid valve, and the start and stop of the corresponding high-temperature molten salt tank is controlled by the solenoid valve.

[0013] The steam medium phase change heat storage power generation system of the present invention uses water vapor as the working medium, phase change materials and liquid molten salt as the heat storage medium, organically combines phase change heat storage and phase change heat transfer, and realizes isothermal heat storage and isothermal storage and access of thermal energy. The capacity cost of the system is 300 yuan / kWh, the power cost is 1,800 yuan / kW, and the efficiency reaches more than 80%. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Attached Figure 1 It is a schematic diagram of the first structure of the steam medium phase change heat storage power generation system of the present invention.

[0016] Attached Figure 2 It is a second structural schematic diagram of the steam medium phase change heat storage power generation system of the present invention.

[0017] Attached Figure 3 It is a third structural schematic diagram of the steam medium phase change heat storage power generation system of the present invention.

[0018] Attached Figure 4 This is a fourth structural schematic diagram of the steam medium phase change heat storage power generation system of the present invention.

[0019] In the figure: 1. low-temperature hot water tank; 2. high-temperature hot water tank; 3. high-temperature molten salt tank; 4. low-temperature molten salt tank; 5. low-temperature phase-change heat storage tank; 6. high-temperature phase-change heat storage tank; 7. expander; 8. compressor; 9. generator; 10. countercurrent heat exchanger; 11. first water pump; 12. first molten salt pump; 13. second molten salt pump; 14. second water pump; 15. first one-way valve; 16. second one-way valve; 17. third one-way valve; 18. fourth one-way valve; 19. exothermic valve; 20. solenoid valve; 21. four-way valve. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below.

[0021] Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments.

[0022] Based on the embodiments of the present invention, all other implementations obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. To make the embodiments easier to understand, the following provides a variety of embodiments or implementation methods to illustrate the relevant devices, modules, and functions of the present invention. Specific implementation method 1

[0024] As attached Figure 1 As shown, the steam medium phase change heat storage power generation system includes a low-temperature phase change heat storage and heat transfer device, a molten salt energy storage device, a high-temperature phase change heat storage and heat transfer device, a compressor 8, an expander 7, a generator 9 and connecting pipelines therebetween, and the expander 7 is connected to the generator 9.

[0025] The low-temperature phase-change heat storage and heat transfer device comprises a low-temperature hot water tank 1, a low-temperature phase-change heat storage tank 5, a first water pump 11, a first one-way valve 15 and connecting pipes therebetween. The low-temperature phase-change heat storage tank 5 is filled with a low-temperature phase-change material, and a heat transfer pipe is arranged around the low-temperature phase-change material; the inlet of the first water pump 11 is connected to the low-temperature hot water tank 1, and the outlet of the first water pump 11 is connected to the heat transfer pipe inside the low-temperature phase-change heat storage tank 5; the inlet of the first one-way valve 15 is connected to the heat transfer pipe inside the low-temperature phase-change heat storage tank 5, and the outlet of the first one-way valve 15 is connected to the low-temperature hot water tank 1; the other end of the heat transfer pipe inside the low-temperature phase-change heat storage tank 5 is connected to the inlet of the compressor 8 and the outlet of the expander 7 respectively.

[0026] The molten salt energy storage device includes a countercurrent heat exchanger 10, a high-temperature molten salt tank 3, a low-temperature molten salt tank 4, a first molten salt pump 12, a second molten salt pump 13, a second one-way valve 16, a third one-way valve 17, and connecting pipes therebetween. The steam channel of the countercurrent heat exchanger 10 is connected to the outlet of the compressor 8 and the inlet of the expander 7; the two ends of the molten salt channel of the countercurrent heat exchanger 10 are connected to the high-temperature molten salt tank 3 and the low-temperature molten salt tank 4 respectively; the first molten salt pump 12 and the second one-way valve 16 are connected in parallel between the high-temperature molten salt tank 3 and the molten salt channel of the countercurrent heat exchanger 10; the second molten salt pump 13 and the third one-way valve 17 are connected in parallel between the low-temperature molten salt tank 4 and the molten salt channel of the countercurrent heat exchanger 10. The installation positions of the high-temperature molten salt tank 3 and the low-temperature molten salt tank 4 are located below the countercurrent heat exchanger 10, forming a certain height difference. When the molten salt energy storage device stores heat, the second molten salt pump 13 extracts the molten salt in the low-temperature molten salt tank 4, and then sends it into the molten salt channel of the countercurrent heat exchanger 10. The low-temperature molten salt absorbs the heat of the heat transfer medium in another channel of the countercurrent heat exchanger 10 to become high-temperature molten salt, and then the high-temperature molten salt returns to the high-temperature molten salt tank 3 through the second one-way valve 16 by gravity. When the molten salt energy storage device releases heat, the first molten salt pump 12 extracts the molten salt in the high-temperature molten salt tank 3, and the high-temperature molten salt is sent into the molten salt channel of the countercurrent heat exchanger 10. The high-temperature molten salt exchanges heat with the heat transfer medium in another channel of the countercurrent heat exchanger 10 to become low-temperature molten salt, and then the low-temperature molten salt returns to the low-temperature molten salt tank 4 through the third one-way valve 17 by gravity.

[0027] The high-temperature phase-change heat storage and heat transfer device comprises a high-temperature hot water tank 2, a high-temperature phase-change heat storage tank 6, a second water pump 14, a fourth one-way valve 18 and connecting pipes therebetween. The high-temperature phase-change heat storage tank 5 is filled with a high-temperature phase-change material, and a heat transfer pipe is arranged around the high-temperature phase-change material; the inlet of the second water pump 14 is connected to the high-temperature hot water tank 2, and the outlet of the second water pump 14 is connected to the heat transfer pipe inside the high-temperature phase-change heat storage tank 6; the outlet of the fourth one-way valve 18 is connected to the high-temperature hot water tank 2, and the inlet of the fourth one-way valve 18 is connected to the heat transfer pipe inside the high-temperature phase-change heat storage tank 6; the other end of the heat transfer pipe inside the high-temperature phase-change heat storage tank 6 is connected to the steam channel of the countercurrent heat exchanger 10.

[0028] The steam medium phase change heat storage power generation system of the present invention has two working modes, namely a heat storage working mode and a power generation working mode.

[0029] In the heat storage working mode: the first water pump 11, the compressor 8 and the second molten salt pump 13 are turned on, and the second water pump 14, the expander 7 and the first molten salt pump 12 are in the off state; the specific working principle is that the first water pump 11 extracts low-temperature hot water from the low-temperature hot water tank 1 and sends it to the low-temperature phase change heat storage tank 5, and the low-temperature hot water performs isothermal heat exchange with the low-temperature phase change material in the low-temperature phase change heat storage tank 5. The low-temperature hot water absorbs the heat in the low-temperature phase change material and becomes low-temperature and low-pressure saturated steam. The low-temperature and low-pressure saturated steam enters the compressor 8 and is compressed into high-temperature and high-pressure superheated steam. The high-temperature and high-pressure superheated steam enters the steam channel of the countercurrent heat exchanger 10. At the same time, the second molten salt pump 13 extracts the low-temperature molten salt in the low-temperature molten salt tank 4 and sends it to the countercurrent heat exchanger 10. In the molten salt channel of the exchanger 10, the low-temperature molten salt absorbs the heat of the high-temperature and high-pressure superheated steam in the steam channel of the countercurrent heat exchanger 10 to become high-temperature molten salt, and then the high-temperature molten salt returns to the high-temperature molten salt tank 3 through the second one-way valve 16 by gravity; and the high-temperature and high-pressure superheated steam in the steam channel of the countercurrent heat exchanger 10 becomes high-temperature and high-pressure saturated steam after quantitative heat release, and then the high-temperature and high-pressure saturated steam enters the high-temperature phase change heat storage tank 6, and undergoes isothermal phase change with the high-temperature phase change material in the high-temperature phase change heat storage tank 6, and the high-temperature and high-pressure saturated steam undergoes isothermal phase change and becomes high-temperature and high-pressure hot water, and the high-temperature and high-pressure hot water is finally sent to the high-temperature hot water tank 2 through the fourth one-way valve 18 to store heat, thereby completing the heat storage working mode.

[0030] In the power generation working mode: the first water pump 11, the compressor 8 and the second molten salt pump 13 are turned off, and the second water pump 14, the expander 7 and the first molten salt pump 12 are turned on; the specific working principle is that the second water pump 14 extracts the high-temperature and high-pressure hot water in the high-temperature hot water tank 2 and sends it to the high-temperature phase change heat storage tank 6, and the high-temperature and high-pressure hot water absorbs the heat of the high-temperature phase change material in the high-temperature phase change heat storage tank 6 to become high-temperature and high-pressure saturated steam, and the high-temperature and high-pressure saturated steam enters the steam channel in the countercurrent heat exchanger 10, and at the same time, the first molten salt pump 12 extracts the high-temperature molten salt in the high-temperature molten salt tank 3 and sends it to the molten salt channel of the countercurrent heat exchanger 10, and the high-temperature and high-pressure saturated steam and the high-temperature molten salt are heat exchanged in the countercurrent heat exchanger 10. In the heat exchanger 10, the high-temperature molten salt releases heat to become low-temperature molten salt, which returns to the low-temperature molten salt tank 4 through the third one-way valve 17 by gravity in the countercurrent heat exchanger 10; at the same time, the high-temperature and high-pressure saturated steam absorbs the heat of the high-temperature molten salt to become high-temperature and high-pressure superheated steam, which enters the expander 7 to do work, and the expander 7 converts thermal energy into mechanical energy to drive the generator 9 to generate electricity, and finally realizes the conversion of thermal energy into electrical energy output; the high-temperature and high-pressure superheated steam after doing work is discharged through the expander as low-pressure water vapor, which enters the low-temperature phase change heat storage tank 5 to exchange heat with the low-temperature phase change material, and the low-pressure water vapor isothermally releases heat to become low-temperature hot water, which is stored in the low-temperature hot water tank 1 through the first one-way valve 15.

[0031] The phase change material in the low-temperature phase change heat storage tank 5 is a low-temperature solid-liquid phase change material. In the heat 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.

[0032] The phase change material in the high-temperature phase change heat storage tank 5 is a high-temperature solid-liquid phase change material. In the heat 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.

[0033] All processes in the heat storage working mode and the power generation working mode are reversible.

[0034] The low-temperature hot water tank 1 is also connected to a heat release valve 19, which is connected to a place requiring low-quality heat, so that the hot water in the low-temperature hot water tank 1 can be used in different places such as low-temperature and low-pressure power generation, winter heating or industrial hot water. Specific implementation method 2

[0036] like Figure 2 As shown, the same as in Example 1 Figure 1 In comparison, the molten salt energy storage device in the steam medium phase change heat storage power generation system of the present invention includes a countercurrent heat exchanger 10, a high-temperature molten salt tank 3, a low-temperature molten salt tank 4, a four-way valve 21, a second molten salt pump 13, and connecting pipes therebetween. The high-temperature molten salt tank 3 is directly connected to the molten salt channel in the countercurrent heat exchanger 10, and a four-way valve 21 and a second molten salt pump 13 are connected between the low-temperature molten salt tank 4 and the countercurrent heat exchanger 10. The connections of other components are the same as in Example 1. When the molten salt energy storage device stores heat, under the action of the second molten salt pump 13, the molten salt in the low-temperature molten salt tank 4 enters the second molten salt pump 13 through the four-way valve 21, and then is sent to the molten salt channel of the countercurrent heat exchanger 10 again through the four-way valve 21. The low-temperature molten salt absorbs the heat of the high-temperature and high-pressure superheated steam in the countercurrent heat exchanger 10 to become high-temperature molten salt, and 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 13, the high-temperature molten salt in the high-temperature molten salt tank 3 is sent into the molten salt channel of the countercurrent heat exchanger 10, and the high-temperature molten salt exchanges heat with the high-temperature and high-pressure saturated steam of the countercurrent heat exchanger 10 to become low-temperature molten salt, and then the low-temperature molten salt returns to the low-temperature molten salt tank 4 through the four-way valve 21 and the second molten salt pump 13 respectively. Figure 2 The working principles of the components in the steam medium phase change thermal storage power generation system shown are the same as those in the first embodiment except for the molten salt energy storage device. Specific implementation method three

[0038] As attached Figure 3Compared with the first embodiment, the steam medium phase change heat storage power generation system of the present invention is shown in that the low-temperature hot water tank 1 is composed of multiple groups of low-temperature hot water tanks connected in parallel, and each low-temperature hot water tank 1 is connected to a solenoid valve 20. When working, when a low-temperature hot water tank 1 is fully loaded, it is directly switched to another low-temperature water storage tank. The high-temperature hot water tank 2 is composed of multiple groups of high-temperature hot water tanks connected in parallel, and each high-temperature hot water tank 2 is connected to a solenoid valve 20. When working, when a high-temperature hot water tank 2 is fully loaded, it is directly switched to another high-temperature water storage tank.

[0039] The low-temperature phase-change heat storage tank 5 is composed of a plurality of low-temperature phase-change heat storage tank groups connected in parallel, and each low-temperature phase-change heat storage tank 5 is connected to an electromagnetic valve 20 at its inlet and outlet. When working, if one low-temperature phase-change heat storage tank 5 is fully loaded, it is directly switched to another low-temperature phase-change heat storage tank. The high-temperature phase-change heat storage tank 6 is composed of a plurality of high-temperature phase-change heat storage tank groups connected in parallel, and each high-temperature phase-change heat storage tank 6 is connected to an electromagnetic valve 20 at its inlet and outlet. When working, if one high-temperature phase-change heat storage tank 6 is fully loaded, it is directly switched to another high-temperature phase-change heat storage tank.

[0040] The low-temperature molten salt tank 4 is composed of a plurality of low-temperature molten salt tank groups connected in parallel, and each low-temperature molten salt tank 4 is connected to a solenoid valve 20. When working, when a low-temperature molten salt tank 4 is fully loaded, it is directly switched to another low-temperature molten salt tank. The high-temperature molten salt tank 3 is composed of a plurality of high-temperature molten salt tank groups connected in parallel, and each high-temperature molten salt tank 3 is connected to a solenoid valve 20. When working, when a high-temperature molten salt tank 3 is fully loaded, it is directly switched to another high-temperature molten salt tank.

[0041] The steam medium phase change heat storage power generation system described above realizes one-to-many, and is suitable for large-scale heat storage power generation sites. Its working principle is the same as that of the first embodiment. Specific implementation method four

[0043] As attached Figure 4 Compared with the second embodiment, the steam medium phase change heat storage power generation system of the present invention is shown in that the low-temperature hot water tank 1 is composed of multiple groups of low-temperature hot water tanks connected in parallel, and each low-temperature hot water tank 1 is connected to a solenoid valve 20. When working, when a low-temperature hot water tank 1 is fully loaded, it is directly switched to another low-temperature water storage tank. The high-temperature hot water tank 2 is composed of multiple groups of high-temperature hot water tanks connected in parallel, and each high-temperature hot water tank 2 is connected to a solenoid valve 20. When working, when a high-temperature hot water tank 2 is fully loaded, it is directly switched to another high-temperature water storage tank.

[0044] The low-temperature phase-change heat storage tank 5 is composed of a plurality of low-temperature phase-change heat storage tank groups connected in parallel, and each low-temperature phase-change heat storage tank 5 is connected to an electromagnetic valve 20 at its inlet and outlet. When working, if one low-temperature phase-change heat storage tank 5 is fully loaded, it is directly switched to another low-temperature phase-change heat storage tank. The high-temperature phase-change heat storage tank 6 is composed of a plurality of high-temperature phase-change heat storage tank groups connected in parallel, and each high-temperature phase-change heat storage tank 6 is connected to an electromagnetic valve 20 at its inlet and outlet. When working, if one high-temperature phase-change heat storage tank 6 is fully loaded, it is directly switched to another high-temperature phase-change heat storage tank.

[0045] The low-temperature molten salt tank 4 is composed of a plurality of low-temperature molten salt tank groups connected in parallel, and each low-temperature molten salt tank 4 is connected to a solenoid valve 20. When working, when a low-temperature molten salt tank 4 is fully loaded, it is directly switched to another low-temperature molten salt tank. The high-temperature molten salt tank 3 is composed of a plurality of high-temperature molten salt tank groups connected in parallel, and each high-temperature molten salt tank 3 is connected to a solenoid valve 20. When working, when a high-temperature molten salt tank 3 is fully loaded, it is directly switched to another high-temperature molten salt tank.

[0046] The steam medium phase change thermal storage power generation system described above realizes one-to-many, and is suitable for large thermal storage power generation sites. Its working principle is the same as that of the second embodiment.

Claims

1. A steam medium phase change thermal storage power generation system, characterized in that: It includes a low-temperature phase-change heat storage and heat transfer device, a molten salt energy storage device, a high-temperature phase-change heat storage and heat transfer device, a compressor, an expander, a generator and connecting pipelines therebetween, wherein the expander is connected to the generator; The low-temperature phase-change heat storage and heat transfer device comprises a low-temperature hot water tank and a low-temperature phase-change heat storage tank; the low-temperature phase-change heat storage tank is filled with a low-temperature phase-change material, and a heat transfer pipe is arranged around the low-temperature phase-change material; one end of the heat transfer pipe of the low-temperature phase-change heat storage tank is connected to the low-temperature hot water tank; the other end of the heat transfer pipe of the low-temperature phase-change heat storage tank is respectively connected to the inlet of the compressor and the outlet of the expander; The molten salt energy storage device comprises a countercurrent heat exchanger, a high-temperature molten salt tank, a low-temperature molten salt tank and connecting pipelines therebetween; the steam channel of the countercurrent heat exchanger is connected to the outlet of the compressor and the inlet of the expander; the two ends of the molten salt channel of the countercurrent heat exchanger are respectively connected to the high-temperature molten salt tank and the low-temperature molten salt tank; The high-temperature phase-change heat storage and heat transfer device comprises a high-temperature hot water tank, a high-temperature phase-change heat storage tank and connecting pipes therebetween; the high-temperature phase-change heat storage tank is filled with a high-temperature phase-change material, and a heat transfer pipe is arranged around the high-temperature phase-change material; the high-temperature hot water tank is connected to the heat transfer pipe inside the high-temperature phase-change heat storage tank; the other end of the heat transfer pipe inside the high-temperature phase-change heat storage tank is connected to the steam channel of the countercurrent heat exchanger.

2. A steam medium phase change thermal storage power generation system as claimed in claim 1, characterized in that: The molten salt energy storage device also includes a first molten salt pump, a second molten salt pump, a second one-way valve, a third one-way valve and connecting pipelines therebetween; the first molten salt pump and the second 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 third one-way valve are connected in parallel between the low-temperature molten salt tank and the molten salt channel of the countercurrent heat exchanger.

3. A steam medium phase change thermal storage power generation system as claimed in claim 1, characterized in that: A first water pump and a first one-way valve are also provided between the low-temperature hot water tank and the low-temperature phase-change heat storage tank; the inlet of the first water pump is communicated with the low-temperature hot water tank, and the outlet of the first water pump is communicated with the heat transfer pipe inside the low-temperature phase-change heat storage tank; the inlet of the first one-way valve is communicated with the heat transfer pipe inside the low-temperature phase-change heat storage tank, and the outlet of the first one-way valve is communicated with the low-temperature hot water tank.

4. A steam medium phase change thermal storage power generation system as claimed in claim 1, characterized in that: A second water pump and a fourth one-way valve are further provided between the high-temperature hot water tank and the high-temperature phase-change heat storage tank; the inlet of the second water pump is communicated with the high-temperature hot water tank, and the outlet of the second water pump is communicated with the heat transfer pipe inside the high-temperature phase-change heat storage tank; the outlet of the fourth one-way valve is communicated with the high-temperature hot water tank, and the inlet of the fourth one-way valve is communicated with the heat transfer pipe inside the high-temperature phase-change heat storage tank; the other end of the heat transfer pipe inside the high-temperature phase-change heat storage tank is communicated with the steam channel of the countercurrent heat exchanger.

5. A steam medium phase change thermal storage power generation system as claimed in claim 1, characterized in that: The molten salt energy storage device includes a countercurrent heat exchanger, a high-temperature molten salt tank, a low-temperature molten salt tank, a four-way valve, a second molten salt pump and connecting pipelines therebetween; 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.

6. A steam medium phase change thermal storage power generation system as claimed in claim 1, characterized in that: The phase change material in the low-temperature phase change heat storage tank is a low-temperature solid-liquid phase change material; the phase change material in the high-temperature phase change heat storage tank is a high-temperature solid-liquid phase change material.

7. A steam medium phase change thermal storage power generation system as claimed in claim 1, characterized in that: The low-temperature hot water tank is composed of multiple groups of low-temperature hot water tanks connected in parallel, and each low-temperature hot water tank is connected to a solenoid valve, which controls the start and stop of the corresponding low-temperature water storage tank; the high-temperature hot water tank is composed of multiple groups of high-temperature hot water tanks connected in parallel, and each high-temperature hot water tank is connected to a solenoid valve, which controls the start and stop of the corresponding high-temperature water storage tank.

8. A steam medium phase change thermal storage power generation system as claimed in claim 1, characterized in that: The low-temperature phase-change heat storage tank is composed of a plurality of parallel low-temperature phase-change heat storage tank groups, and each low-temperature phase-change heat storage tank inlet and outlet are connected to a solenoid valve, and the start and stop of the corresponding low-temperature phase-change heat storage tank are controlled by the solenoid valve; the high-temperature phase-change heat storage tank is composed of a plurality of parallel high-temperature phase-change heat storage tank groups, and each high-temperature phase-change heat storage tank inlet and outlet are connected to a solenoid valve, and the start and stop of the corresponding high-temperature phase-change heat storage tank are controlled by the solenoid valve.

9. A steam medium phase change thermal storage power generation system as claimed in claim 1, characterized in that: The low-temperature molten salt tank is composed of multiple groups of low-temperature molten salt tanks connected in parallel, and each low-temperature molten salt tank is connected to a solenoid valve, and the start and stop of the corresponding low-temperature molten salt tank is controlled by the solenoid valve; the high-temperature molten salt tank is composed of multiple groups of high-temperature molten salt tanks connected in parallel, and each high-temperature molten salt tank is connected to a solenoid valve, and the start and stop of the corresponding high-temperature molten salt tank is controlled by the solenoid valve.

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