A carbon dioxide energy storage and power generation system

Abstract

The present invention relates to the field of energy storage technology, and in particular to a carbon dioxide energy storage and power generation system, comprising: a cryogenic liquid carbon dioxide storage tank; a gas-liquid separation pressure-stabilizing tank connected to the cryogenic liquid carbon dioxide storage tank through a booster pump; a carbon dioxide generator connected to the gas-liquid separation pressure-stabilizing tank; a heating subsystem heating the carbon dioxide in the carbon dioxide generator; a first turbine connected to the carbon dioxide generator; a carbon dioxide liquefier connected to the first turbine; a carbon dioxide supercooler connected to the carbon dioxide liquefier and to an input end of the cryogenic liquid carbon dioxide storage tank; the carbon dioxide supercooler continues to reduce the temperature of the carbon dioxide to form cryogenic liquid carbon dioxide; in the present application, the carbon dioxide on the high-pressure side is already in a liquid state, and the carbon dioxide liquefier and the carbon dioxide supercooler are used on the low-pressure side to gradually reduce the temperature of the carbon dioxide to make it in a liquid state, so as to make full use of the excellent power performance of carbon dioxide and significantly improve the work output capacity per unit carbon dioxide working fluid.

Description

Technical Field

[0001] The present invention relates to the field of energy storage technology, and in particular to a carbon dioxide energy storage and power generation system. Background Art

[0002] In the field of energy storage technology, compressed gas energy storage can be used, and carbon dioxide energy storage is an important branch of compressed gas energy storage. The critical point parameters of carbon dioxide energy storage are 7.38MPa, 31.3℃; if carbon dioxide is maintained in the liquid phase, the carbon dioxide needs to be reduced to below room temperature. When carbon dioxide is liquefied on the high-pressure side, the upper limit of the carbon dioxide work pressure is limited; when carbon dioxide is liquefied on the low-pressure side, the temperature factor limits the lower limit of the work pressure. How to improve the work output capacity of unit carbon dioxide working fluid is a technical problem that needs to be solved urgently. Summary of the invention

[0003] Therefore, the technical problem to be solved by the present invention is how to improve the work output capacity per unit of carbon dioxide working fluid when using carbon dioxide for energy storage.

[0004] In order to solve the above technical problems, the present invention provides a carbon dioxide energy storage and power generation system, comprising: a low-temperature liquid carbon dioxide storage tank, a gas-liquid separation pressure stabilizing tank, a carbon dioxide generator, a heating subsystem, a first turbine, a carbon dioxide liquefier and a carbon dioxide supercooler;

[0005] The cryogenic liquid carbon dioxide storage tank is suitable for storing cryogenic liquid carbon dioxide;

[0006] The gas-liquid separation pressure-stabilizing tank is connected to the output end of the cryogenic liquid carbon dioxide storage tank via a booster pump;

[0007] The carbon dioxide input end of the carbon dioxide generator is connected to the gas output end of the gas-liquid separation pressure-stabilizing tank;

[0008] One end of the heating subsystem is connected to the heat exchange medium inlet of the carbon dioxide generator, and the other end of the heating subsystem is connected to the heat exchange medium outlet of the carbon dioxide generator; the heating subsystem is suitable for heating the carbon dioxide in the carbon dioxide generator;

[0009] The first turbine is connected to a carbon dioxide output terminal of the carbon dioxide generator; the first turbine is suitable for utilizing the heated gaseous carbon dioxide to expand and generate electricity;

[0010] The carbon dioxide liquefier is connected to the first turbine, and the carbon dioxide liquefier is suitable for liquefying the utilized gaseous carbon dioxide;

[0011] The input end of the carbon dioxide supercooler is connected to the carbon dioxide liquefier, and the output end of the carbon dioxide supercooler is connected to the input end of the cryogenic liquid carbon dioxide storage tank; the carbon dioxide supercooler is suitable for further reducing the temperature of liquid carbon dioxide or supercritical carbon dioxide to form cryogenic liquid carbon dioxide, and transporting it to the cryogenic liquid carbon dioxide storage tank.

[0012] Optionally, it also includes: a cooler;

[0013] The input end of the cooler is connected to the liquid output end of the gas-liquid separation pressure-stabilizing tank; the output end of the cooler is connected to the input end of the carbon dioxide generator; the cooler is suitable for taking cold through the refrigerant carrier provided inside to discharge the cold of liquid carbon dioxide; the carbon dioxide generator heats the liquid carbon dioxide and converts it into gaseous carbon dioxide under the action of the heating subsystem.

[0014] Optionally, the refrigerant output end of the cooling device is connected to the input cold end of the carbon dioxide liquefier, and the refrigerant return end of the cooling device is connected to the output cold end of the carbon dioxide liquefier; and the carbon dioxide liquefier is suitable for releasing the cold in the refrigerant.

[0015] Optionally, a cold storage device is provided on the pipeline connecting the refrigerant output end of the cold extraction device and the cold input end of the carbon dioxide liquefier; the cold storage device is suitable for temporarily storing the refrigerant after cold extraction.

[0016] Optionally, the heating subsystem comprises: a low-temperature heat storage tank, a heating unit and a high-temperature heat storage tank connected in sequence;

[0017] The heating unit is suitable for heating the heat exchange medium transmitted by the low-temperature heat storage tank and transmitting it to the input end of the high-temperature heat storage tank; the output end of the high-temperature heat storage tank and the input end of the low-temperature heat storage tank are both connected to the carbon dioxide generator; the heat exchange medium output by the high-temperature heat storage tank is suitable for heating the carbon dioxide in the carbon dioxide generator.

[0018] Optionally, it further comprises: a carbon dioxide reheater and a second turbine disposed between the first turbine and the carbon dioxide liquefier;

[0019] The carbon dioxide reheater is connected to the second turbine; the input end of the carbon dioxide reheater is connected to the output end of the first turbine, and the output end of the second turbine is connected to the carbon dioxide liquefier; the carbon dioxide reheater is suitable for receiving the carbon dioxide after being utilized by the first turbine;

[0020] The output end of the high-temperature heat storage tank and the input end of the low-temperature heat storage tank are both connected to the carbon dioxide reheater; the heat exchange medium output by the high-temperature heat storage tank is suitable for heating the carbon dioxide in the carbon dioxide reheater; the second turbine is suitable for expanding and generating electricity using the gaseous carbon dioxide transmitted by the carbon dioxide reheater.

[0021] Optionally, a second three-way valve is provided on the pipeline connecting the output end of the high-temperature heat storage tank and the carbon dioxide generator; a third three-way valve is provided on the pipeline connecting the input end of the low-temperature heat storage tank and the carbon dioxide reheater;

[0022] The first end of the second three-way valve is connected to the output end of the high-temperature heat storage tank, the second end of the second three-way valve is connected to the first end of the third three-way valve, and the third end of the second three-way valve is connected to the carbon dioxide generator; the second end of the third three-way valve is connected to the carbon dioxide reheater, and the third end of the third three-way valve is connected to the input end of the low-temperature heat storage tank;

[0023] The carbon dioxide energy storage and power generation system is suitable for heating the carbon dioxide in the carbon dioxide reheater and the carbon dioxide generator in sequence when the first end of the second three-way valve is closed, the second end of the second three-way valve is opened, the third end of the second three-way valve is opened, the first end of the third three-way valve is opened, the second end of the third three-way valve is opened, and the third end of the third three-way valve is closed.

[0024] Optionally, it further comprises: a carbon dioxide cooler disposed between the second turbine and the carbon dioxide liquefier;

[0025] The carbon dioxide cooler is connected to the first air cooling tower; the carbon dioxide cooler and the first air cooling tower are suitable for releasing heat to the environment from the carbon dioxide used by the second turbine.

[0026] Optionally, the heating unit is a photothermal conversion unit and / or an electric boiler; the electric boiler is powered by new energy electricity.

[0027] Optionally, the heat exchange medium is pressurized water, heat transfer oil or molten salt.

[0028] Optionally, it also includes: a direct drive battery pack;

[0029] The direct-drive battery pack is connected to a boost pump, and the direct-drive battery pack is powered by new energy electricity.

[0030] Optionally, an exhaust compressor is provided between the gas-liquid separation pressure stabilizing tank and the carbon dioxide generator; one end of the exhaust compressor is connected to the gas output end of the gas-liquid separation pressure stabilizing tank, and the other end of the exhaust compressor is connected to the carbon dioxide generator.

[0031] Optionally, it also includes: a heat pump compressor and a second air cooling tower;

[0032] One end of the heat pump compressor is connected to a carbon dioxide supercooler;

[0033] One end of the second air cooling tower is connected to the heat pump compressor, and the other end of the second air cooling tower is connected to the carbon dioxide supercooler; the heat pump compressor cooperates with the second air cooling tower to provide cooling capacity for the carbon dioxide supercooler.

[0034] Optionally, it also includes: a cold source;

[0035] One end of the cold source is connected to the pipeline between the second air cooling tower and the heat pump compressor; the other end of the cold source is connected to the pipeline between the second air cooling tower and the carbon dioxide supercooler.

[0036] Optionally, the cold source is a ground source or a water source.

[0037] The above technical solution of the present invention has the following advantages compared with the prior art:

[0038] 1. The carbon dioxide energy storage and power generation system provided by the present invention comprises: a cryogenic liquid carbon dioxide storage tank, a gas-liquid separation pressure-stabilizing tank, a carbon dioxide generator, a heating subsystem, a first turbine, a carbon dioxide liquefier and a carbon dioxide supercooler; the cryogenic liquid carbon dioxide storage tank is suitable for storing cryogenic liquid carbon dioxide; the gas-liquid separation pressure-stabilizing tank is connected to the output end of the cryogenic liquid carbon dioxide storage tank through a booster pump; the carbon dioxide input end of the carbon dioxide generator is connected to the gas output end of the gas-liquid separation pressure-stabilizing tank; one end of the heating subsystem is connected to the heat exchange medium inlet provided by the carbon dioxide generator, and the other end of the heating subsystem is connected to the heat exchange medium outlet provided by the carbon dioxide generator; the heating subsystem is suitable for heating the carbon dioxide in the carbon dioxide generator; the first turbine is connected to the carbon dioxide output end provided by the carbon dioxide generator; the first turbine is connected to the carbon dioxide output end provided by the carbon dioxide generator; A turbine is suitable for utilizing heated gaseous carbon dioxide for expansion and power generation; the carbon dioxide liquefier is connected to the first turbine, and the carbon dioxide liquefier is suitable for liquefying the utilized gaseous carbon dioxide; the input end of the carbon dioxide supercooler is connected to the carbon dioxide liquefier, and the output end of the carbon dioxide supercooler is connected to the input end of the cryogenic liquid carbon dioxide storage tank; the carbon dioxide supercooler is suitable for further reducing the temperature of liquid carbon dioxide or supercritical carbon dioxide to form cryogenic liquid carbon dioxide, and transporting it to the cryogenic liquid carbon dioxide storage tank; the present application adopts the above technical scheme, the carbon dioxide on the high-pressure side is already in liquid state, and the carbon dioxide liquefier and the carbon dioxide supercooler are used on the low-pressure side to gradually reduce the temperature of carbon dioxide to make it in liquid state, making full use of the excellent power performance of carbon dioxide, and significantly improving the output capacity of unit carbon dioxide working fluid. When the general compressed air process is used for energy storage, the storage volume of carbon dioxide is too large. The present application utilizes low-temperature carbon dioxide storage, utilizes the high-density characteristics of the carbon dioxide liquid phase, significantly reduces the storage volume, greatly reduces the number of carbon dioxide storage tanks, and greatly reduces the gas storage cost. In addition, carbon dioxide cannot be discharged, and a new growth point for carbon dioxide consumption can be formed by promoting the carbon dioxide working fluid cycle.

[0039] 2. The carbon dioxide energy storage and power generation system provided by the present invention also includes: a cooler; the input end of the cooler is connected to the liquid output end of the gas-liquid separation pressure-stabilizing tank; the output end of the cooler is connected to the input end of the carbon dioxide generator; the cooler is suitable for taking cold through the refrigerant carrier provided inside to discharge the cold of liquid carbon dioxide; the carbon dioxide generator heats the liquid carbon dioxide and converts it into gaseous carbon dioxide under the action of the heating subsystem; the present application adopts the above-mentioned technical scheme to increase the temperature of the carbon dioxide on the high-pressure side through the cooler, reduce the subsequent heating input, improve the work capacity, and save energy.

[0040] 3. The refrigerant output end of the refrigerator described in the present invention is connected to the input cold end of the carbon dioxide liquefier, and the refrigerant return end of the refrigerator is connected to the output cold end of the carbon dioxide liquefier; the carbon dioxide liquefier is suitable for releasing the cold in the refrigerant; the present application adopts the above technical scheme to fully utilize the cold of the liquid carbon dioxide on the high-pressure side to liquefy the carbon dioxide on the low-pressure side, which not only increases the temperature of the carbon dioxide on the high-pressure side and improves the working capacity, but also reduces the temperature of the carbon dioxide on the low-pressure side, which is beneficial to liquefaction storage; using local materials, killing two birds with one stone, reducing costs and improving efficiency.

[0041] 4. The present invention provides a cold storage device on the pipeline connecting the refrigerant output end of the cold extraction device and the input cold end of the carbon dioxide liquefier; the cold storage device is suitable for temporarily storing the refrigerant after cooling; the present application adopts the above technical scheme, and temporarily stores the cold energy through the cold storage device, which can be used from the cold storage device at any time when needed, thereby increasing the flexibility of using the cold energy and improving the operating efficiency.

[0042] 5. The carbon dioxide energy storage and power generation system provided by the present invention also includes: a carbon dioxide reheater and a second turbine arranged between the first turbine and the carbon dioxide liquefier; the carbon dioxide reheater and the second turbine are connected; the input end of the carbon dioxide reheater is connected to the output end of the first turbine, and the output end of the second turbine is connected to the carbon dioxide liquefier; the carbon dioxide reheater is suitable for receiving the carbon dioxide after utilization by the first turbine; the output end of the high-temperature heat storage tank and the input end of the low-temperature heat storage tank are both connected to the carbon dioxide reheater; the heat exchange medium output by the high-temperature heat storage tank is suitable for heating the carbon dioxide in the carbon dioxide reheater; the second turbine is suitable for utilizing the gaseous carbon dioxide transmitted by the carbon dioxide reheater to expand and generate electricity; the present application adopts the above technical solution, and improves the utilization rate of the carbon dioxide working medium by utilizing the carbon dioxide working medium twice to generate electricity, thereby significantly improving the work output capacity per unit of carbon dioxide working medium.

[0043] 6. The present invention is provided with a second three-way valve on the pipeline connecting the output end of the high-temperature heat storage tank and the carbon dioxide generator; a third three-way valve is provided on the pipeline connecting the input end of the low-temperature heat storage tank and the carbon dioxide reheater; the first end of the second three-way valve is connected to the output end of the high-temperature heat storage tank, the second end of the second three-way valve is connected to the first end of the third three-way valve, and the third end of the second three-way valve is connected to the carbon dioxide generator; the second end of the third three-way valve is connected to the carbon dioxide reheater, and the third end of the third three-way valve is connected to the input end of the low-temperature heat storage tank; the carbon dioxide energy storage and power generation system is suitable for connecting the second three-way valve and the third three-way valve. When the first end of the three-way valve is closed, the second end of the second three-way valve is opened, the third end of the second three-way valve is opened, the first end of the third three-way valve is opened, the second end of the third three-way valve is opened, and the third end of the third three-way valve is closed, the heating subsystem heats the carbon dioxide in the carbon dioxide reheater and the carbon dioxide generator in sequence; the present application adopts the above technical solution, and by heating the carbon dioxide in the carbon dioxide reheater and the carbon dioxide generator in sequence, it makes full use of thermal energy, saves energy, and reduces costs; and through the on-off combination of different three-way valves, it is possible to easily achieve conversion between separate heating and sequential heating.

[0044] 7. The carbon dioxide energy storage and power generation system provided by the present invention also includes: a carbon dioxide cooler arranged between the second turbine and the carbon dioxide liquefier; the carbon dioxide cooler is connected to the first air-cooling tower; the carbon dioxide cooler and the first air-cooling tower are suitable for releasing heat to the environment from the carbon dioxide after utilization by the second turbine; the present application adopts the above technical solution to make full use of the ambient temperature, reduce the temperature of the carbon dioxide after utilization, save the energy consumption required for the subsequent liquefaction of carbon dioxide, and reduce costs.

[0045] 8. The heating unit described in the present invention is a photothermal conversion unit and / or an electric boiler; the electric boiler is powered by renewable energy electricity; the present application adopts the above technical solution, which can be regarded as an adjustable equipment when storing energy through the form of storing potential energy and / or thermal energy separately. Compared with the compressor of compressed gas energy storage, on the one hand, it can completely decouple heat and mass, and realize the production on demand separately; on the other hand, its adjustability is much higher than that of the compressor. In addition, the photothermal conversion unit and / or electric boiler can push carbon dioxide to a high-parameter Brayton cycle with higher cycle efficiency. At the same time, the electric boiler can absorb unstable renewable energy electricity.

[0046] 9. The carbon dioxide energy storage and power generation system provided by the present invention also includes: a direct-drive battery pack; the direct-drive battery pack is connected to a boost pump, and the direct-drive battery pack is powered by new energy electricity; the present application adopts the above technical solution, and unstable new energy electricity can be stored through the direct-drive battery pack, and then consumed by the boost pump.

[0047] 10. The present invention provides an exhaust compressor between the gas-liquid separation pressure-stabilizing tank and the carbon dioxide generator; one end of the exhaust compressor is connected to the gas output end of the gas-liquid separation pressure-stabilizing tank, and the other end of the exhaust compressor is connected to the carbon dioxide generator; the present application adopts the above technical scheme, when the accumulated amount of gaseous carbon dioxide in the gas-liquid separation pressure-stabilizing tank is large, it can be pressurized by the exhaust compressor and incorporated into the carbon dioxide generator to ensure a good operating state.

[0048] 11. The carbon dioxide energy storage and power generation system provided by the present invention also includes: a heat pump compressor and a second air-cooling tower; one end of the heat pump compressor is connected to the carbon dioxide supercooler; one end of the second air-cooling tower is connected to the heat pump compressor, and the other end of the second air-cooling tower is connected to the carbon dioxide supercooler; the heat pump compressor cooperates with the second air-cooling tower to provide cooling for the carbon dioxide supercooler; the present application adopts the above technical solution to make full use of the ambient temperature to obtain cooling carbon dioxide, which is particularly suitable for low temperature seasonal conditions, has higher efficiency and significantly saves costs.

[0049] 12. The carbon dioxide energy storage and power generation system provided by the present invention also includes: a cold source; one end of the cold source is connected to the pipeline between the second air-cooling tower and the heat pump compressor; the other end of the cold source is connected to the pipeline between the second air-cooling tower and the carbon dioxide supercooler; the present application adopts the above technical solution, fully utilizes the cold source combined with the ambient temperature, obtains cold supercooled carbon dioxide, which is particularly suitable for high temperature seasonal conditions.

[0050] 13. The cold source described in the present invention is a ground source or a water source; this application adopts the above technical solution, and only a small amount of cold energy is needed to supplement the cold energy loss caused by storage heat loss through the above common cold source; the cost is lower. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0052] Figure 1 Schematic diagram of the connection structure of the carbon dioxide energy storage and power generation system provided in an embodiment of the present invention.

[0053] Description of reference numerals:

[0054] 1. Low temperature liquid carbon dioxide storage tank; 2. Cold storage device; 3. Low temperature heat storage tank; 4. High temperature heat storage tank; 5. Gas-liquid separation and stabilizing tank; 6. Cooling device; 7. Carbon dioxide generator; 8. Carbon dioxide reheater; 9. Carbon dioxide cooler; 10. Carbon dioxide liquefier; 11. Carbon dioxide supercooler; 12. Booster pump; 13. Air extraction compressor; 14. First turbine; 15. Second turbine; 16. Cold storage pump; 17. First drive pump; 18. Second drive pump; 19. Heat pump compressor; 20. Photothermal conversion unit; 21. Electric boiler; 22. First air-cooling tower; 23. Second air-cooling tower; 24. Cold source; 25. First three-way valve; 26. Second three-way valve; 27. Third three-way valve; 28. Fourth three-way valve; 29. ​​Fifth three-way valve; 30. Sixth three-way valve; 31. Seventh three-way valve; 32. Expansion valve; 33. Eighth three-way valve; 34. Ninth three-way valve; 35. Thirteenth three-way valve; 36. Eleventh three-way valve; 37. Twelfth three-way valve; 38. Direct-drive battery pack; 39. Third drive pump. DETAILED DESCRIPTION

[0055] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0057] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0058] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0059] like Figure 1 A specific embodiment of the carbon dioxide energy storage and power generation system shown includes: a low-temperature liquid carbon dioxide storage tank 1, a gas-liquid separation pressure-regulating tank 5, a carbon dioxide generator 7, a first turbine 14, a carbon dioxide reheater 8, a second turbine 15, a carbon dioxide cooler 9, a carbon dioxide liquefier 10 and a carbon dioxide supercooler 11 connected in sequence, a cold source 24, a second air-cooling tower 23 and a heat pump compressor 19 connected in sequence, a cooler 6 connected to the gas-liquid separation pressure-regulating tank 5, and a heating subsystem and a direct-drive battery pack 38.

[0060] The cryogenic liquid carbon dioxide storage tank 1 is suitable for storing cryogenic liquid carbon dioxide. The low-pressure point of carbon dioxide energy storage designed in this application is the liquid storage point of the energy storage cycle, -40-0°C, so that the subsequent turbine outlet is pressurized to below 3.5MPa, thereby improving the power output level of the low-pressure section of the turbine. The gas-liquid separation pressure-stabilizing tank 5 is connected to the output end of the cryogenic liquid carbon dioxide storage tank 1 through a booster pump 12. Specifically, the direct-drive battery pack 38 is connected to the booster pump 12, and the direct-drive battery pack 38 is powered by new energy electricity. The carbon dioxide input end of the carbon dioxide generator 7 is connected to the gas output end of the gas-liquid separation stabilizing tank 5; one end of the heating subsystem is connected to the heat exchange medium inlet provided by the carbon dioxide generator 7, and the other end of the heating subsystem is connected to the heat exchange medium outlet provided by the carbon dioxide generator 7; the heating subsystem is suitable for heating the carbon dioxide in the carbon dioxide generator 7; the first turbine 14 is connected to the carbon dioxide output end provided by the carbon dioxide generator 7; the first turbine 14 is suitable for expanding and generating electricity using the heated gaseous carbon dioxide; the carbon dioxide liquefier 10 is connected to the first turbine 14, and the carbon dioxide liquefier 10 is suitable for liquefying the gaseous carbon dioxide after use. The input end of the carbon dioxide supercooler 11 is connected to the carbon dioxide liquefier 10, and the output end of the carbon dioxide supercooler 11 is connected to the input end of the low-temperature liquid carbon dioxide storage tank 1; the carbon dioxide supercooler 11 is suitable for further reducing the temperature of the liquid carbon dioxide or supercritical carbon dioxide to form low-temperature liquid carbon dioxide, and transport it to the low-temperature liquid carbon dioxide storage tank 1. Furthermore, an exhaust compressor 13 is provided between the gas-liquid separation pressure stabilizing tank 5 and the carbon dioxide generator 7 ; one end of the exhaust compressor 13 is connected to the gas output end of the gas-liquid separation pressure stabilizing tank 5 , and the other end of the exhaust compressor 13 is connected to the carbon dioxide generator 7 .

[0061] The input end of the cooler 6 is connected to the liquid output end of the gas-liquid separation pressure-stabilizing tank 5; the output end of the cooler 6 is connected to the input end of the carbon dioxide generator 7; the cooler 6 is suitable for taking cold through the refrigerant carrier provided inside to discharge the coldness of liquid carbon dioxide; the carbon dioxide generator 7 heats the liquid carbon dioxide and converts it into gaseous carbon dioxide under the action of the heating subsystem. The refrigerant carrier output end of the cooler 6 is connected to the input cold end of the carbon dioxide liquefier 10, and the refrigerant carrier return end of the cooler 6 is connected to the output cold end of the carbon dioxide liquefier 10; the carbon dioxide liquefier 10 is suitable for releasing the coldness in the refrigerant carrier. Specifically, a ninth three-way valve 34, a cold storage pump 16 and a thirteenth three-way valve 35 can be sequentially arranged on the pipeline connecting the refrigerant output end of the cold taker 6 and the input cold end of the carbon dioxide liquefier 10; an eleventh three-way valve 36 is arranged on the pipeline connecting the refrigerant return end of the cold taker 6 and the output cold end of the carbon dioxide liquefier 10; the cold storage pump 16 is used to speed up the transmission of the refrigerant; and the flow direction of the refrigerant is controlled by the on-off of each three-way valve.

[0062] Furthermore, a cold storage device 2 is provided on the pipeline connecting the refrigerant output end of the cold taker 6 and the cold input end of the carbon dioxide liquefier 10; the cold storage device 2 is suitable for temporarily storing the refrigerant after cold taking. Specifically, the refrigerant can be an ethylene glycol solution. An eighth three-way valve 33 can be provided on the pipeline connecting the refrigerant output end of the cold taker 6 and the cold storage device 2, and a twelfth three-way valve 37 can be provided on the pipeline connecting the cold input end of the carbon dioxide liquefier 10 and the cold storage device 2. When temporary storage of cold is required, the cold storage device 2 is connected, and when temporary storage is not required, the cold taker 6 directly provides cold to the carbon dioxide liquefier 10 by controlling the on-off of the three-way valve. Of course, the cold storage device 2 storing cold can also directly provide cold to the carbon dioxide liquefier 10 by controlling the on-off of the three-way valve.

[0063] The heating subsystem includes: a low-temperature heat storage tank 3, a heating unit and a high-temperature heat storage tank 4 connected in sequence. Specifically, the heating unit is a photothermal conversion unit and / or an electric boiler; the electric boiler is powered by new energy electricity. The heating unit is suitable for heating the low-temperature heat exchange medium transmitted by the low-temperature heat storage tank 3 to form a high-temperature heat exchange medium, and transmit it to the input end of the high-temperature heat storage tank 4; the output end of the high-temperature heat storage tank 4 and the input end of the low-temperature heat storage tank 3 are both connected to the carbon dioxide generator 7; the high-temperature heat exchange medium output by the high-temperature heat storage tank 4 is suitable for heating the carbon dioxide in the carbon dioxide generator 7. The input end of the carbon dioxide reheater 8 is connected to the output end of the first turbine 14, and the output end of the second turbine 15 is connected to the carbon dioxide liquefier 10; the carbon dioxide reheater 8 is suitable for receiving the carbon dioxide after being used by the first turbine 14; the output end of the high-temperature heat storage tank 4 and the input end of the low-temperature heat storage tank 3 are both connected to the carbon dioxide reheater 8; the high-temperature heat exchange medium output by the high-temperature heat storage tank 4 is suitable for heating the carbon dioxide in the carbon dioxide reheater 8; the second turbine 15 is suitable for expanding and generating electricity using the gaseous carbon dioxide transmitted by the carbon dioxide reheater 8. Specifically, the heat exchange medium is pressurized water, heat transfer oil or molten salt, etc. The selection of the specific heat exchange medium depends on the heat storage parameters.

[0064] Further, a second three-way valve 26 is provided on the pipeline connecting the output end of the high-temperature heat storage tank 4 and the carbon dioxide generator 7; a third three-way valve 27 is provided on the pipeline connecting the input end of the low-temperature heat storage tank 3 and the carbon dioxide reheater 8; a first end of the second three-way valve 26 is connected to the output end of the high-temperature heat storage tank 4, a second end of the second three-way valve 26 is connected to the first end of the third three-way valve 27, and a third end of the second three-way valve 26 is connected to the carbon dioxide generator 7; a second end of the third three-way valve 27 is connected to the carbon dioxide reheater 8, and a third end of the third three-way valve 27 is connected to the input end of the low-temperature heat storage tank 3; the carbon dioxide energy storage and power generation system is suitable for heating the carbon dioxide in the carbon dioxide reheater 8 and the carbon dioxide generator 7 in sequence when the first end of the second three-way valve 26 is closed, the second end of the second three-way valve 26 is opened, the third end of the second three-way valve 26 is opened, the first end of the third three-way valve 27 is opened, the second end of the third three-way valve 27 is opened, and the third end of the third three-way valve 27 is closed. Furthermore, a first driving pump 17 is provided on the pipeline connecting the heating unit and the high-temperature heat storage tank 4, and a second driving pump 18 is provided on the pipeline near the output end of the high-temperature heat storage tank 4 to speed up the transmission of the heat exchange medium. A fourth three-way valve 28 is provided on the pipeline connecting the first end of the second three-way valve 26 and the output end of the high-temperature heat storage tank 4, and the fourth three-way valve 28 is also connected to the carbon dioxide reheater 8. A first three-way valve 25 is provided on the pipeline near the input end of the low-temperature heat storage tank 3. By providing the above three-way valves, the on-off and direction of the heat exchange medium transmission can be better controlled.

[0065] The carbon dioxide cooler 9 is connected to the first air cooling tower 22; the carbon dioxide cooler 9 and the first air cooling tower 22 cooperate to release heat from the carbon dioxide used by the second turbine 15 to the environment.

[0066] One end of the heat pump compressor 19 is connected to the carbon dioxide supercooler 11; one end of the second air cooling tower 23 is connected to the heat pump compressor 19, and the other end of the second air cooling tower 23 is connected to the carbon dioxide supercooler 11; the heat pump compressor 19 cooperates with the second air cooling tower 23 to provide cooling capacity for the carbon dioxide supercooler 11. Specifically, a sixth three-way valve 30 is provided on the pipeline connecting one end of the second air cooling tower 23 to the heat pump compressor 19; a seventh three-way valve 31 and an expansion valve 32 are sequentially provided on the pipeline connecting the other end of the second air cooling tower 23 to the carbon dioxide supercooler 11.

[0067] One end of the cold source 24 is connected to the pipeline between the second air-cooling tower 23 and the heat pump compressor 19; the other end of the cold source 24 is connected to the pipeline between the second air-cooling tower 23 and the carbon dioxide supercooler 11. Specifically, the cold source 24 is a ground source or a water source. One end of the cold source 24 is connected to the sixth three-way valve 30, and the other end of the cold source 24 is connected to the seventh three-way valve 31. Through the opening and closing of the sixth three-way valve 30 and the seventh three-way valve 31, in high temperature seasonal conditions, the second air-cooling tower 23 first performs a heat dissipation, and the cold source 24 then performs a second heat dissipation; in low temperature seasonal conditions, only the second air-cooling tower 23 is used to completely dissipate heat.

[0068] Furthermore, a fifth three-way valve 29 is connected between the carbon dioxide supercooler 11, the carbon dioxide liquefier and the cryogenic liquid carbon dioxide storage tank 1; and a third driving pump 39 is provided on the pipeline connecting the fifth three-way valve 29 and the cryogenic liquid carbon dioxide storage tank 1. Through the above arrangement, the carbon dioxide supercooler 11 is used to maintain the supercooling degree of carbon dioxide in the cryogenic liquid carbon dioxide storage tank 1.

[0069] The main working process of the carbon dioxide energy storage and power generation system described in this application is briefly described as follows: During energy storage, the unstable electricity of new energy supplies power to the direct-drive battery pack 38, and the heat medium (i.e., heat exchange medium) starts from the low-temperature heat storage tank 3, and is heated by the photothermal conversion unit 20 and the electric boiler 21 (the two can be used in combination or separately), and enters the high-temperature heat storage tank 4 for storage; wherein, the electric boiler 21 also consumes the unstable electricity of new energy. The supercooling in the low-temperature liquid carbon dioxide storage tank 1 is constructed through the low-temperature liquid carbon dioxide storage tank 1, the carbon dioxide supercooler 11, the heat pump compressor 19, the second air cooling tower 23, the cold source 24, the sixth three-way valve 30, the seventh three-way valve 31 and the expansion valve 32 to form an independent cycle, which is also an energy storage process.

[0070] When releasing energy, low-temperature liquid carbon dioxide starts from the low-temperature liquid carbon dioxide storage tank 1, and the direct-drive battery pack 38 drives the booster pump 12 to pressurize the liquid carbon dioxide. The low-temperature and high-pressure liquid carbon dioxide enters the gas-liquid separation and pressure-stabilizing tank 5, and the gaseous carbon dioxide generated due to resistance and the like is retained in the gas-liquid separation and pressure-stabilizing tank 5 (when the accumulated amount of gaseous carbon dioxide is large, it can be pressurized by the exhaust compressor 13 and incorporated into the carbon dioxide generator 7). The low-temperature liquid carbon dioxide output by the gas-liquid separation and pressure-stabilizing tank 5 discharges the cold through the cooler 6, and the refrigerant can use ethylene glycol solution as the working medium.

[0071] In the process of discontinuous energy release, the cold storage pump 16 can provide power, and then the eighth three-way valve 33, the ninth three-way valve 34, the thirteenth three-way valve 35 and the twelfth three-way valve 37 can be combined to establish a process to form a loop, and the cold energy can be first recovered to the cold storage device 2; and then the ninth three-way valve 34, the thirteenth three-way valve 35 and the twelfth three-way valve 37 can be used to establish a process to form a loop to release the cold energy to the carbon dioxide liquefier 10. In the process of continuous energy release, the cold storage pump 16 can provide power, and then the eighth three-way valve 33, the ninth three-way valve 34, the thirteenth three-way valve 35, the eleventh three-way valve 36 and the twelfth three-way valve 37 can be combined to establish a process to form a loop to discharge the cold energy directly to the carbon dioxide liquefier 10.

[0072] After the low-temperature gas phase carbon dioxide is discharged (preheated), it enters the carbon dioxide generator 7 for vaporization, expands and generates electricity through the first turbine 14, and then the carbon dioxide reheater 8 further heats the exhaust steam and expands and generates electricity through the second turbine 15. The two heating processes in the carbon dioxide generator 7 and the carbon dioxide reheater 8 are provided by the high-temperature heat storage tank 4 (the heat exchange medium can be selected from pressurized water, heat transfer oil or molten salt according to the design temperature range). The second driving pump 18 provides circulation power, and the hot end heating process of the carbon dioxide generator 7 and the carbon dioxide reheater 8 can be realized in series or in parallel through the combination of different on and off of the first three-way valve 25, the second three-way valve 26, the third three-way valve 27 and the fourth three-way valve 28. After the carbon dioxide working medium is expanded and generates electricity through the second turbine 15, it enters the carbon dioxide cooler 9 and releases heat to the environment side at the first air cooling tower 22. Then, the carbon dioxide in the room temperature section after heat release enters the carbon dioxide liquefier 10, absorbs the cold from the cooler 6 or the cold storage device 2 for liquefaction or pre-cooling, and the pre-cooled supercritical carbon dioxide or liquid carbon dioxide enters the carbon dioxide supercooler 11 for supercooling or complete liquefaction, and is sent to the low-temperature liquid carbon dioxide storage tank 1 for storage, completing the energy release and storage cycle.

[0073] The cold source in the carbon dioxide supercooler 11 comes from the compression refrigeration cycle constructed by the carbon dioxide supercooler 11, the heat pump compressor 19, the second air cooling tower 23, the cold source 24, the sixth ground (water) three-way valve 30, the seventh three-way valve 31 and the expansion valve 32. Through the regulation of the sixth three-way valve 30 and the seventh three-way valve 31, in the high temperature season, the second air cooling tower 23 first performs the primary heat removal and the cold source 24 then performs the secondary heat removal; in the low temperature season, only the second air cooling tower 23 is used to completely remove heat.

[0074] In addition, in order to ensure the supercooling degree in the cryogenic liquid carbon dioxide storage tank 1, an independent cycle is constructed through the cryogenic liquid carbon dioxide storage tank 1, the carbon dioxide supercooler 11, the heat pump compressor 19, the second air cooling tower 23, the cold source 24, the sixth three-way valve 30, the seventh three-way valve 31, the expansion valve 32 and the third drive pump 39, and when the supercooling degree needs to be maintained, it serves as an energy storage process.

[0075] Obviously, the above embodiments are merely examples for clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from them are still within the protection scope of the invention.

Claims

1. A carbon dioxide energy storage and power generation system, characterized in that: include: A low-temperature liquid carbon dioxide storage tank (1), a gas-liquid separation pressure-regulating tank (5), a carbon dioxide generator (7), a heating subsystem, a first turbine (14), a carbon dioxide liquefier (10) and a carbon dioxide subcooler (11); The cryogenic liquid carbon dioxide storage tank (1) is suitable for storing cryogenic liquid carbon dioxide; The gas-liquid separation pressure-stabilizing tank (5) is connected to the output end of the cryogenic liquid carbon dioxide storage tank (1) via a booster pump (12); The carbon dioxide input end of the carbon dioxide generator (7) is connected to the gas output end of the gas-liquid separation pressure-stabilizing tank (5); One end of the heating subsystem is connected to a heat exchange medium inlet provided in the carbon dioxide generator (7), and the other end of the heating subsystem is connected to a heat exchange medium outlet provided in the carbon dioxide generator (7); the heating subsystem is suitable for heating carbon dioxide in the carbon dioxide generator (7); The first turbine (14) is connected to a carbon dioxide output terminal provided in the carbon dioxide generator (7); the first turbine (14) is suitable for utilizing the heated gaseous carbon dioxide to expand and generate electricity; The carbon dioxide liquefier (10) is connected to the first turbine (14), and the carbon dioxide liquefier (10) is suitable for liquefying the utilized gaseous carbon dioxide; The input end of the carbon dioxide supercooler (11) is connected to the carbon dioxide liquefier (10), and the output end of the carbon dioxide supercooler (11) is connected to the input end of the cryogenic liquid carbon dioxide storage tank (1); the carbon dioxide supercooler (11) is suitable for further reducing the temperature of liquid carbon dioxide or supercritical carbon dioxide to form cryogenic liquid carbon dioxide, and transporting it to the cryogenic liquid carbon dioxide storage tank (1); The heating subsystem comprises: a low-temperature heat storage tank (3), a heating unit and a high-temperature heat storage tank (4) connected in sequence; The heating unit is suitable for heating the heat exchange medium transmitted by the low-temperature heat storage tank (3) and transmitting it to the input end of the high-temperature heat storage tank (4); the output end of the high-temperature heat storage tank (4) and the input end of the low-temperature heat storage tank (3) are both connected to the carbon dioxide generator (7); the heat exchange medium output by the high-temperature heat storage tank (4) is suitable for heating the carbon dioxide in the carbon dioxide generator (7); It also includes: a carbon dioxide reheater (8) and a second turbine (15) disposed between the first turbine (14) and the carbon dioxide liquefier (10); The carbon dioxide reheater (8) is connected to the second turbine (15); the input end of the carbon dioxide reheater (8) is connected to the output end of the first turbine (14), and the output end of the second turbine (15) is connected to the carbon dioxide liquefier (10); the carbon dioxide reheater (8) is suitable for receiving carbon dioxide after being utilized by the first turbine (14); The output end of the high-temperature heat storage tank (4) and the input end of the low-temperature heat storage tank (3) are both connected to the carbon dioxide reheater (8); the heat exchange medium output by the high-temperature heat storage tank (4) is suitable for heating the carbon dioxide in the carbon dioxide reheater (8); the second turbine (15) is suitable for expanding the gaseous carbon dioxide transmitted by the carbon dioxide reheater (8) to generate electricity; A second three-way valve (26) is provided on the pipeline connecting the output end of the high-temperature heat storage tank (4) and the carbon dioxide generator (7); and a third three-way valve (27) is provided on the pipeline connecting the input end of the low-temperature heat storage tank (3) and the carbon dioxide reheater (8); The first end of the second three-way valve (26) is connected to the output end of the high-temperature heat storage tank (4), the second end of the second three-way valve (26) is connected to the first end of the third three-way valve (27), and the third end of the second three-way valve (26) is connected to the carbon dioxide generator (7); the second end of the third three-way valve (27) is connected to the carbon dioxide reheater (8), and the third end of the third three-way valve (27) is connected to the input end of the low-temperature heat storage tank (3); The carbon dioxide energy storage and power generation system is suitable for, when the first end of the second three-way valve (26) is closed, the second end of the second three-way valve (26) is opened, the third end of the second three-way valve (26) is opened, the first end of the third three-way valve (27) is opened, the second end of the third three-way valve (27) is opened, and the third end of the third three-way valve (27) is closed, the heating subsystem heats the carbon dioxide in the carbon dioxide reheater (8) and the carbon dioxide generator (7) in sequence; The heating unit is a photothermal conversion unit and / or an electric boiler; the electric boiler is powered by new energy electricity; Also included: a direct drive battery pack (38); The direct-drive battery pack (38) is connected to the boost pump (12), and the direct-drive battery pack (38) is powered by new energy electricity.

2. The carbon dioxide energy storage and power generation system according to claim 1, characterized in that: Also includes: Cooler (6); The input end of the refrigeration device (6) is connected to the liquid output end of the gas-liquid separation pressure-stabilizing tank (5); the output end of the refrigeration device (6) is connected to the input end of the carbon dioxide generator (7); the refrigeration device (6) is suitable for taking cold through the refrigerant provided inside to discharge the cold of liquid carbon dioxide; the carbon dioxide generator (7) heats the liquid carbon dioxide and converts it into gaseous carbon dioxide under the action of the heating subsystem.

3. The carbon dioxide energy storage and power generation system according to claim 2, characterized in that: The refrigerant output end of the refrigeration device (6) is connected to the input cold end of the carbon dioxide liquefier (10), and the refrigerant return end of the refrigeration device (6) is connected to the output cold end of the carbon dioxide liquefier (10); the carbon dioxide liquefier (10) is suitable for releasing the cold in the refrigerant.

4. The carbon dioxide energy storage and power generation system according to claim 3, characterized in that: A cold storage device (2) is provided on the pipeline connecting the refrigerant output end of the cold extraction device (6) and the cold input end of the carbon dioxide liquefier (10); the cold storage device (2) is suitable for temporarily storing the refrigerant after cold extraction.

5. The carbon dioxide energy storage and power generation system according to claim 1, characterized in that: Also includes: a carbon dioxide cooler (9) disposed between the second turbine (15) and the carbon dioxide liquefier (10); The carbon dioxide cooler (9) is connected to the first air cooling tower (22); the carbon dioxide cooler (9) and the first air cooling tower (22) cooperate to release heat from the carbon dioxide used by the second turbine (15) to the environment.

6. The carbon dioxide energy storage and power generation system according to claim 1, characterized in that: The heat exchange medium is pressurized water, heat transfer oil or molten salt.

7. The carbon dioxide energy storage and power generation system according to any one of claims 1 to 4, characterized in that: An air extraction compressor (13) is provided between the gas-liquid separation pressure stabilizing tank (5) and the carbon dioxide generator (7); one end of the air extraction compressor (13) is connected to the gas output end of the gas-liquid separation pressure stabilizing tank (5), and the other end of the air extraction compressor (13) is connected to the carbon dioxide generator (7).

8. The carbon dioxide energy storage and power generation system according to any one of claims 1 to 4, characterized in that: Also includes: A heat pump compressor (19) and a second air cooling tower (23); One end of the heat pump compressor (19) is connected to the carbon dioxide supercooler (11); One end of the second air cooling tower (23) is connected to the heat pump compressor (19), and the other end of the second air cooling tower (23) is connected to the carbon dioxide supercooler (11); the heat pump compressor (19) and the second air cooling tower (23) cooperate to provide cooling capacity for the carbon dioxide supercooler (11).

9. The carbon dioxide energy storage and power generation system according to claim 8, characterized in that: Also includes: Cold source (24); One end of the cold source (24) is connected to the pipeline between the second air cooling tower (23) and the heat pump compressor (19); the other end of the cold source (24) is connected to the pipeline between the second air cooling tower (23) and the carbon dioxide supercooler (11).

10. The carbon dioxide energy storage and power generation system according to claim 9, characterized in that: The cold source (24) is a ground source or a water source.

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