Carbon dioxide circulating energy storage system

Abstract

The invention belongs to the technical field of carbon dioxide energy storage, and discloses a carbon dioxide circulating energy storage system. According to the carbon dioxide circulation energy storage system, the energy release pipeline and the energy storage pipeline are communicated or cut off through an arranged control valve. A first ejector, a first generator and a second generator are arranged on the energy release pipeline; the energy release pipeline comprises a direct pipeline, a secondary flow pipeline and a connecting pipeline; the high-pressure liquid CO2 storage tank is connected with an inlet of the first ejector through a direct pipeline, and the high-pressure liquid CO2 storage tank is connected with a secondary flow inlet of the first ejector through a secondary flow pipeline; one end of the connecting pipeline is connected with an outlet of the first ejector, and the high-pressure liquid CO2 storage tank is connected with an inlet of the low-pressure liquid CO2 storage tank through the connecting pipeline; the first generator is arranged on the secondary flow pipeline; and the second generator is arranged on the connecting pipeline. According to the invention, a composite cascade energy release operation mode is adopted, so that the efficiency of converting energy into electric energy is effectively improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of carbon dioxide energy storage, in particular to a carbon dioxide circulating energy storage system. BACKGROUND

[0003] Although the liquid CO2 energy storage system can improve the energy storage density and enhance the system flexibility, the system performance still needs to be improved and perfected. In the energy storage and release process, the energy conversion, utilization and transmission path are not optimized, resulting in meaningless loss of part of the energy, which affects the actual benefit of the whole system.

[0004] Therefore, it is urgent to provide a carbon dioxide circulating energy storage system with higher energy conversion efficiency and more flexible energy storage and release process regulation to solve the above problems.

[0005] In view of this, the present application is proposed. SUMMARY

[0006] The technical problem to be solved by the present application is to overcome the low conversion efficiency and low flexibility of the existing technology in the energy storage and release process. The purpose is to provide a carbon dioxide circulating energy storage system with higher energy conversion efficiency and more flexible energy storage and release process regulation.

[0007] To solve the above technical problems, the basic idea of the technical scheme adopted by the present application is as follows: a carbon dioxide circulating energy storage system, comprising an energy storage pipeline for converting low-pressure liquid CO2 into high-pressure liquid CO2 and storing it in a high-pressure liquid CO2 storage tank, and an energy release pipeline for converting high-pressure liquid CO2 into low-pressure liquid CO2 and storing it in a low-pressure liquid CO2 storage tank;

[0008] The energy release pipeline and the energy storage pipeline are connected or cut off by the control valve provided therebetween;

[0009] The energy release pipeline is provided with a first ejector, a first generator and a second generator;

[0010] The energy release pipeline comprises a direct pipeline, a secondary flow pipeline and a connecting pipeline; the high-pressure liquid CO2 storage tank is connected with the inlet of the first ejector through the direct pipeline, and the high-pressure liquid CO2 storage tank is connected with the secondary flow inlet of the first ejector through the secondary flow pipeline; one end of the connecting pipeline is connected with the outlet of the first ejector, and the high-pressure liquid CO2 storage tank is connected with the inlet of the low-pressure liquid CO2 storage tank through the connecting pipeline;

[0011] The first generator is arranged on the secondary flow pipeline;

[0012] The second generator is arranged on the connecting pipeline.

[0013] According to an embodiment of the present application, the energy storage pipeline is provided with a first methanol heat exchanger, a first compressor, a first heat exchanger, a second compressor, a second heat exchanger, a third compressor, a third heat exchanger and a condenser connected in sequence.

[0014] The inlet of the outer pipe of the first methanol heat exchanger is connected with the outlet of the low-pressure liquid CO2 storage tank, and the outlet of the outer pipe of the first methanol heat exchanger is communicated with the inlet of the first compressor.

[0015] The outlet of the first compressor is connected with the inlet of the outer pipe of the first heat exchanger, and the outlet of the outer pipe of the third heat exchanger is connected with the inlet of the condenser.

[0016] The first compressor, the second compressor and the third compressor are driven by the same motor.

[0017] According to an embodiment of the present application, one end of the energy release pipeline is communicated with the outlet of the high-pressure liquid CO2 storage tank, and the other end is communicated with the inlet of the low-pressure liquid CO2 storage tank.

[0018] The one end of the direct pipeline and the secondary flow pipeline close to the high-pressure liquid CO2 storage tank is connected with the outlet of the high-pressure liquid CO2 storage tank, and the outlet end of the high-pressure liquid CO2 storage tank is provided with a first pump for controlling the delivery of high-pressure liquid CO2 in the high-pressure liquid CO2 storage tank to the direct pipeline and / or the indirect pipeline.

[0019] The connecting pipeline is provided with a fourth heat exchanger, a third expander, a fifth heat exchanger, a fourth expander, a sixth heat exchanger, a fifth expander and a third ejector communicated in sequence, the outlet of the first ejector is connected with the inlet of the outer pipe of the fourth heat exchanger, and the outlet of the fifth expander is communicated with the inlet of the third ejector.

[0020] The direct pipeline is provided with a first preheater, and the one end of the direct pipeline away from the outlet of the high-pressure liquid CO2 storage tank is provided with a first branch pipe and a second branch pipe.

[0021] The first branch pipe is provided with a first valve, and the first branch pipe is connected with the inlet of the first ejector; the second branch pipe is provided with a second valve, and the second branch pipe is connected with the inlet of the outer pipe of the fourth heat exchanger.

[0022] According to an embodiment of the present application, the third expander, the fourth expander and the fifth expander jointly drive the second generator.

[0023] According to an embodiment of the present application, the connecting pipeline is further provided with a second methanol heat exchanger, a second throttle valve and a second gas-liquid separator which are sequentially connected in communication.

[0024] The outlet of the third ejector is connected with the inlet of the outer pipe of the second methanol heat exchanger.

[0025] The outlet of the outer pipe of the second methanol heat exchanger is connected with the second throttle valve.

[0026] The liquid outlet of the second gas-liquid separator is communicated with the inlet of the low-pressure liquid CO2 storage tank, and the gas outlet of the second gas-liquid separator is connected with the secondary flow inlet of the third ejector.

[0027] According to an embodiment of the present application, the carbon dioxide cycle energy storage system further comprises a high-temperature methanol tank and a low-temperature methanol tank, the outlet end of the high-temperature methanol tank is connected with the inlet of the heat exchange pipe of the first methanol heat exchanger, and the inlet end of the high-temperature methanol tank is connected with the outlet end of the heat exchange pipe of the second methanol heat exchanger.

[0028] The inlet end of the low-temperature methanol tank is connected with the outlet end of the heat exchange pipe of the first methanol heat exchanger, and the outlet end of the low-temperature methanol tank is connected with the inlet end of the heat exchange pipe of the second methanol heat exchanger.

[0029] According to an embodiment of the present application, the carbon dioxide cycle energy storage system further comprises a third pump and a cascade refrigeration unit, and the cascade refrigeration unit controls the temperature of the low-temperature methanol tank.

[0030] The heat exchange medium in the cascade refrigeration unit is heat exchange oil.

[0031] According to an embodiment of the present application, the indirect pipeline is provided with a third valve, a second preheater, a heater, a first expander, a second expander, a second pre-cooler, a high-temperature regenerator, a low-temperature regenerator, a re-compressor, a first pre-cooler and a main compressor.

[0032] The outer pipe of the second preheater is communicated with one pipe of the heater.

[0033] The outlet of the first expander is communicated with the inlet of the second pipe of the heater, and the outlet of the second pipe of the heater is connected with the inlet of the second expander.

[0034] The second expander comprises a first outlet and a second outlet, the first outlet of the second expander is connected with the inlet of the outer pipe of the second pre-cooler, and the second outlet of the second expander is connected with the high-temperature regenerator.

[0035] The heat exchange pipe of the second preheater is communicated with the heat exchange pipe of the second pre-cooler, and the heat exchange medium in the heat exchange pipe is methanol.

[0036] The outlet of the outer tube of the second pre-cooler is connected with the secondary flow inlet of the first ejector;

[0037] The high-temperature regenerator comprises a first outlet and a second outlet, the first outlet of the high-temperature regenerator is connected with a tube of the heater, and the second outlet of the high-temperature regenerator is in communication with the inlet of the low-temperature regenerator;

[0038] The low-temperature regenerator comprises a first outlet, a second outlet and a third outlet, the first outlet of the low-temperature regenerator is connected with the high-temperature regenerator, the second outlet of the low-temperature regenerator is connected with the re-compressor, and the third outlet of the low-temperature regenerator is connected with the inlet of the outer tube of the first pre-cooler;

[0039] The outlet of the outer tube of the first pre-cooler is connected with the main compressor;

[0040] The re-compressor is connected with the high-temperature regenerator;

[0041] The main compressor is connected with the low-temperature regenerator;

[0042] The heat exchange tube of the first pre-cooler is connected with the heat exchange tube of the second pre-heater, and the heat exchange medium in the heat exchange tube is methanol.

[0043] According to an embodiment of the present application, the carbon dioxide cycle energy storage system further comprises an air cooler, a heat storage oil tank, a fifth pump and a cold storage oil tank;

[0044] The cold storage oil tank is used for adjusting the temperature of the air cooler, and the heat exchange medium in the cold storage oil tank is heat exchange oil;

[0045] The outlet end of the heat exchange tube of the fourth heat exchanger, the outlet end of the heat exchange tube of the fifth heat exchanger and the outlet end of the heat exchange tube of the sixth heat exchanger are in communication with the inlet end of the cold storage oil tank, and the outlet end of the cold storage oil tank is in communication with the inlet end of the heat storage oil tank;

[0046] The outlet end of the heat storage oil tank is connected with the inlet end of the heat exchange tube of the fourth heat exchanger, the inlet end of the heat exchange tube of the fifth heat exchanger and the inlet end of the heat exchange tube of the sixth heat exchanger.

[0047] According to an embodiment of the present application, the carbon dioxide cycle energy storage system further comprises a fourth pump, a cold storage water tank, an evaporator, a first throttling valve, a second ejector, a first gas-liquid separator and a fourth compressor;

[0048] The cold storage water tank is connected with the inlet end of the heat exchange tube of the first heat exchanger, the inlet end of the heat exchange tube of the second heat exchanger and the inlet end of the heat exchange tube of the third heat exchanger through the fourth pump, and the heat exchange medium is water.

[0049] The evaporator comprises a first inner pipe and a second inner pipe; the outlet of the heat exchange pipe of the first heat exchanger, the outlet of the heat exchange pipe of the third heat exchanger and the outlet of the heat exchange pipe of the third heat exchanger are all communicated with the inlet of the first inner pipe of the evaporator; the outlet of the first inner pipe of the evaporator is connected with the inlet of the cold water storage tank; one end of the second inner pipe of the evaporator is connected with the secondary flow inlet of the second ejector, and the other end is connected with the liquid outlet of the first gas-liquid separator through a first throttling valve;

[0050] The outlet of the second ejector is connected with the inlet of the first gas-liquid separator.

[0051] The gas outlet of the first gas-liquid separator is connected with the inlet of the fourth compressor, the outlet of the fourth compressor is connected with the inlet of the air cooler, and the outlet of the condenser is connected with the inlet of the second ejector.

[0052] Compared with the prior art, the technical scheme has the following beneficial effects:

[0053] In the application, the generators are arranged on different pipelines, so that the energy change of CO2 in the system can be fully utilized for power generation under different working conditions. The first generator and the second generator can work under suitable conditions respectively, thereby improving the adaptability of the system to different working conditions, and the system can be efficiently and stably operated in the case of energy storage capacity change or external power demand fluctuation.

[0054] The specific embodiments of the application will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0055] The accompanying drawings, which are part of the present application, serve to provide a further understanding of the application, and the illustrative embodiments of the application and their descriptions serve to explain the application, but do not constitute an improper limitation on the application. Obviously, the accompanying drawings described below are only some embodiments, and other drawings can be obtained by those skilled in the art without creative labor. In the drawings:

[0056] Figure 1 The accompanying drawings are schematic diagrams of the relative connection relationship of the components of the carbon dioxide cycle energy storage system in the embodiments of the application.

[0057] It should be noted that these drawings and written descriptions are not intended to limit the scope of the concept of the application in any way, but to illustrate the concept of the application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0058] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments with reference to the drawings in the embodiments of the present application. The following embodiments are used to explain the present application, but are not used to limit the scope of the present application.

[0059] In the description of the present application, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0060] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0061] As shown in Figure 1 The carbon dioxide circulating energy storage system comprises an energy storage pipeline for converting low-pressure liquid CO2 into high-pressure liquid CO2 and storing the high-pressure liquid CO2 in a high-pressure liquid CO2 storage tank, and an energy release pipeline for converting high-pressure liquid CO2 into low-pressure liquid CO2 and storing the low-pressure liquid CO2 in a low-pressure liquid CO2 storage tank. The energy release pipeline and the energy storage pipeline are connected or cut off by the control valves (first valve, second valve and third valve) arranged thereon.

[0062] In a specific embodiment of the present embodiment, a first ejector, a first generator and a second generator are arranged on the energy release pipeline.

[0063] The energy release pipeline comprises a direct pipeline, a secondary flow pipeline and a connecting pipeline. The high-pressure liquid CO2 storage tank is connected with the inlet of the first ejector through the direct pipeline, and the high-pressure liquid CO2 storage tank is connected with the secondary flow inlet of the first ejector through the secondary flow pipeline. One end of the connecting pipeline is connected with the outlet of the first ejector, and the high-pressure liquid CO2 storage tank is connected with the inlet of the low-pressure liquid CO2 storage tank through the connecting pipeline (i.e., the direct pipeline, the secondary flow pipeline and the connecting pipeline are connected with the inlet, the secondary flow inlet and the outlet of the first ejector, respectively).

[0064] The first generator is arranged on the secondary flow pipeline.

[0065] The second generator is arranged on the connecting pipeline.

[0066] The carbon dioxide circulating energy storage system has the following characteristics:

[0067] 1) High energy conversion efficiency: The carbon dioxide circulating energy storage system has a unique energy release pipeline design, with a first ejector, a first generator and a second generator. In the energy release process, high-pressure liquid CO2 is discharged from the high-pressure liquid CO2 storage tank, part of which enters the first ejector inlet through the direct pipeline, and the other part enters the secondary flow inlet of the first ejector through the secondary flow pipeline. This dual-path design enables the first ejector to more efficiently utilize the energy of CO2, thereby driving the first generator arranged on the secondary flow pipeline and the second generator arranged on the connecting pipeline to work, achieving multi-stage utilization of energy and effectively improving the efficiency of energy conversion to electrical energy.

[0068] 2) Flexible energy storage and release control: The energy release pipeline and the energy storage pipeline are connected or cut off by control valves. This design enables the system to flexibly open or close the energy storage and release process according to actual power demand and energy storage status. During the low power demand period, the energy release pipeline is closed, and the low-pressure liquid CO2 is converted into high-pressure liquid CO2 and stored in the high-pressure liquid CO2 storage tank for energy storage. During the peak power demand period, the control valve is opened, and the high-pressure liquid CO2 is released for power generation through the energy release pipeline, providing a flexible adjustment means for power supply and better adapting to the peak and valley changes of the power grid, ensuring the stability and reliability of power supply.

[0069] 3) Optimized system structure: By setting the ejector element, the energy release pipeline structure is combined with the direct pipeline, secondary flow pipeline and connecting pipeline, which optimizes the flow and energy distribution of CO2 compared with the single pipeline structure. Different pipelines have their own functions, respectively responsible for transporting high-pressure liquid CO2 to different parts of the first ejector, and transporting CO2 from the first ejector outlet to the low-pressure liquid CO2 storage tank, making the energy transmission path of the entire system more reasonable, reducing energy loss in the transmission process, and also reducing the pressure requirement of the system on the equipment, prolonging the service life of the equipment, and improving the overall stability and reliability of the system.

[0070] 4) Improve system adaptability: by setting generators on different pipelines, the system can fully utilize the energy changes of CO2 in different working conditions. For example, when the high-pressure liquid CO2 flow and pressure change, the first ejector can dynamically adjust the working state according to the input of CO2 in the secondary flow pipeline and the direct pipeline, so that the first generator and the second generator can work under their respective appropriate conditions, thereby improving the adaptability of the system to different working conditions. Whether the energy storage capacity changes or the external power demand fluctuates, the system can run efficiently and stably.

[0071] Please refer to the attached Figure 1 In the figure, the black pipeline represents the carbon dioxide circulation path, the red pipeline represents the methanol circulation path, the blue pipeline represents the water circulation path, and the green pipeline represents the oil circulation path.

[0072] In a specific embodiment of the present embodiment, a first methanol heat exchanger, a first compressor, a first heat exchanger, a second compressor, a second heat exchanger, a third compressor, a third heat exchanger and a condenser are sequentially connected on the energy storage pipeline.

[0073] The inlet of the outer pipe of the first methanol heat exchanger is connected with the outlet of the low-pressure liquid CO2 storage tank, and the outlet of the outer pipe of the first methanol heat exchanger is communicated with the inlet of the first compressor.

[0074] The outlet of the first compressor is connected with the inlet of the outer pipe of the first heat exchanger.

[0075] The outlet of the outer pipe of the first heat exchanger is connected with the inlet of the first compressor.

[0076] The outlet of the second compressor is connected with the inlet of the outer pipe of the second heat exchanger.

[0077] The outlet of the outer pipe of the second heat exchanger is connected with the inlet of the third compressor.

[0078] The outlet of the third compressor is connected with the inlet of the outer pipe of the third heat exchanger.

[0079] The outlet of the outer pipe of the third heat exchanger is connected with the inlet of the condenser.

[0080] The outlet of the condenser is connected with the inlet of the high-pressure liquid CO2 storage tank.

[0081] In a specific embodiment of the present embodiment, the first compressor, the second compressor and the third compressor are driven by the same motor.

[0082] More specifically, the first compressor, the second compressor and the third compressor are all rotary shaft compressors (containing rotary shafts); the rotary shaft of the first compressor, the rotary shaft of the second compressor and the rotary shaft of the third compressor are connected integrally through a shaft coupling and are driven by the driving shaft of the motor.

[0083] It should be noted that the components with heat exchange function in the present application (for example, the first methanol heat exchanger, the third heat exchanger, the first preheater, the second pre-cooler, etc.) all have outer pipes and heat exchange pipes, wherein the heat exchange pipes contain heat exchange medium.

[0084] It should also be noted that the rotational speed and power of the first compressor, the second compressor and the third compressor driven by the same motor can be different, and the transmission ratio and the model (specification) of the compressors can be selected as needed.

[0085] Of course, three compressors can be provided with different motors, and the model (specification) of the respective motors and the model (specification) of the respective compressors can be selected as needed.

[0086] In a specific embodiment of the present application, one end of the energy release pipeline is in communication with the outlet of the high-pressure liquid CO2 storage tank, and the other end is in communication with the inlet of the low-pressure liquid CO2 storage tank.

[0087] Please refer to the accompanying drawings Figure 1 In a specific embodiment of the present application, one end of the direct pipeline and the secondary flow pipeline is connected with the outlet of the high-pressure liquid CO2 storage tank; the outlet end of the high-pressure liquid CO2 storage tank is provided with a first pump, and the first pump controls the delivery of high-pressure liquid CO2 in the high-pressure liquid CO2 storage tank to the direct pipeline and / or the indirect pipeline.

[0088] The connecting pipeline is provided with a fourth heat exchanger, a third expander, a fifth heat exchanger, a fourth expander, a sixth heat exchanger, a fifth expander and a third ejector in sequence, and the outlet of the first ejector is connected with the inlet of the outer pipe of the fourth heat exchanger.

[0089] The outlet of the outer pipe of the fourth heat exchanger is connected with the inlet of the third expander.

[0090] The outlet of the third expander is connected with the inlet of the outer pipe of the fifth heat exchanger.

[0091] The outlet of the outer pipe of the fifth heat exchanger is connected with the inlet of the fourth expander.

[0092] The outlet of the fourth expander is connected with the inlet of the outer pipe of the sixth heat exchanger.

[0093] The outlet of the outer pipe of the sixth heat exchanger is connected with the inlet of the fifth expander;

[0094] The outlet of the fifth expander is communicated with the inlet of the third ejector.

[0095] The direct pipeline is provided with a first preheater, and a first branch pipe and a second branch pipe are arranged at one end of the direct pipeline away from the outlet of the high-pressure liquid CO2 storage tank;

[0096] The first branch pipe is provided with a first valve, and the first branch pipe is connected with the inlet of the first ejector; the second branch pipe is provided with a second valve, and the second branch pipe is connected with the inlet of the outer pipe of the fourth heat exchanger.

[0097] In the application, the multi-stage (the first and second expanders are the first stage, and the third, fourth and fifth expanders are the second stage) recovery expansion work is arranged to replace the traditional throttle valve, so that energy waste is avoided.

[0098] In a specific embodiment of the embodiment, the third expander, the fourth expander and the fifth expander jointly drive the second generator to generate power.

[0099] In a specific embodiment of the embodiment, the connecting pipeline is further provided with a second methanol heat exchanger, a second throttle valve and a second gas-liquid separator which are sequentially communicated;

[0100] The outlet of the third ejector is connected with the inlet of the outer pipe of the second methanol heat exchanger;

[0101] The outlet of the outer pipe of the second methanol heat exchanger is connected with the second gas-liquid separator through the second throttle valve;

[0102] The liquid outlet of the second gas-liquid separator is communicated with the inlet of the low-pressure liquid CO2 storage tank, and the gas outlet of the second gas-liquid separator is connected with the secondary flow inlet of the third ejector.

[0103] In the application, the third ejector is arranged to reduce the pressure and temperature of the carbon dioxide at the outlet of the expander, so that the gas is more likely to condense before entering the liquid CO2 storage tank, and the consumption of the phase change material is reduced.

[0104] In a specific embodiment of the embodiment, the carbon dioxide cycle energy storage system further comprises a high-temperature methanol tank and a low-temperature methanol tank, the outlet end of the high-temperature methanol tank is connected with the inlet of the heat exchange pipe of the first methanol heat exchanger, and the inlet end of the high-temperature methanol tank is connected with the outlet end of the heat exchange pipe of the second methanol heat exchanger;

[0105] The inlet end of the low-temperature methanol tank is connected with the outlet end of the heat exchange pipe of the first methanol heat exchanger, and the outlet end of the low-temperature methanol tank is connected with the inlet end of the heat exchange pipe of the second methanol heat exchanger.

[0106] Please refer to the accompanying drawings Figure 1 In a specific embodiment of the embodiment, the carbon dioxide cycle energy storage system further comprises a third pump and a cascade refrigeration unit, and the cascade refrigeration system controls the temperature of the low-temperature methanol tank.

[0107] The heat exchange medium in the cascade refrigeration unit is heat exchange oil.

[0108] In the present application, by arranging the cascade refrigeration unit, the compression energy consumption can be reduced and the system efficiency can be improved.

[0109] In a specific embodiment of the embodiment (not shown in the drawings), the cascade refrigeration unit is circulated and transported through a circulating pipe;

[0110] The third pump is arranged on the circulating pipe;

[0111] The circulating pipe is at least partially annular and spirally arranged on (or in) the low-temperature methanol tank, so as to reduce the temperature of the heat exchange medium (methanol) therein.

[0112] Please refer to the accompanying drawings Figure 1 In a specific embodiment of the embodiment, the indirect pipe is provided with a third valve, a second preheater, a heater, a first expander, a second expander, a second pre-cooler, a high-temperature regenerator, a low-temperature regenerator, a re-compressor, a first pre-cooler and a main compressor.

[0113] The heater has a pipe and a pipe;

[0114] The outer pipe of the second preheater is in communication with the pipe of the heater;

[0115] The outlet of the pipe of the heater is connected with the inlet of the first expander;

[0116] The outlet of the first expander is in communication with the inlet of the pipe of the heater, and the outlet of the pipe of the heater is connected with the inlet of the second expander;

[0117] The second expander comprises a first outlet and a second outlet, the first outlet of the second expander is connected with the inlet of the outer pipe of the second pre-cooler, and the second outlet of the second expander is connected with the high-temperature regenerator;

[0118] The heat exchange pipe of the second preheater is in communication with the heat exchange pipe of the second pre-cooler, and the heat exchange medium therein is methanol;

[0119] The outlet of the outer pipe of the second pre-cooler is connected with the secondary flow inlet of the first ejector;

[0120] The high-temperature regenerator comprises a first outlet and a second outlet, and the first outlet of the high-temperature regenerator is also connected with a pipe of the heater, and the second outlet of the high-temperature regenerator is in communication with the first inlet of the low-temperature regenerator;

[0121] The low-temperature regenerator comprises a first inlet, a second inlet, a first outlet, a second outlet and a third outlet, the first outlet of the low-temperature regenerator is connected with the high-temperature regenerator, the second outlet of the low-temperature regenerator is connected with the re-compressor, and the third outlet of the low-temperature regenerator is connected with the inlet of the outer pipe of the first pre-cooler;

[0122] The outlet of the outer pipe of the first pre-cooler is connected with the main compressor;

[0123] The re-compressor is connected with the high-temperature regenerator;

[0124] The main compressor is connected with the second inlet of the low-temperature regenerator;

[0125] The heat exchange pipe of the first pre-cooler is connected with the heat exchange pipe of the second pre-heater, and the heat exchange medium in the heat exchange pipe is methanol.

[0126] In the energy releasing process, the high-pressure liquid CO2 is preheated by the second pre-heater, enters the heater to absorb heat, and then enters the first expander to do work; the CO2 at the outlet of the first expander enters the heater to absorb heat again, and then enters the second expander to do work; then, the CO2 is divided into two streams, one part enters the second pre-cooler to exchange heat with the second pre-heater, and then enters the first ejector; the other part passes through the high-temperature regenerator and the low-temperature regenerator in sequence to release heat, and the CO2 at the outlet of the low-temperature regenerator is then divided into two parts, one part enters the re-compressor to be compressed, and the other part enters the main compressor to be compressed after being cooled by the first pre-cooler, and then enters the low-temperature regenerator to increase the temperature; then, the two parts of working medium are combined, enter the high-temperature regenerator to increase the temperature, and finally enter the heater to absorb heat again, so as to complete the whole cycle process.

[0127] In a specific embodiment of the embodiment, the first expander and the second expander jointly drive the first generator to generate electricity.

[0128] Please refer to the accompanying drawings Figure 1 In a specific embodiment of the embodiment, the carbon dioxide cycle energy storage system further comprises an air cooler, a heat storage oil tank, a fifth pump and a cold storage oil tank.

[0129] The cold storage oil tank is used for adjusting the temperature of the air cooler, and the heat exchange medium in the cold storage oil tank is heat exchange oil.

[0130] The outlet end of the heat exchange pipe of the fourth heat exchanger, the outlet end of the heat exchange pipe of the fifth heat exchanger, and the outlet end of the heat exchange pipe of the sixth heat exchanger are in communication with the inlet end of the cold storage oil tank; and the outlet end of the cold storage oil tank is in communication with the inlet end of the heat storage oil tank.

[0131] The outlet end of the heat storage oil tank is connected with the inlet end of the heat exchange pipe of the fourth heat exchanger, the inlet end of the heat exchange pipe of the fifth heat exchanger, and the inlet end of the heat exchange pipe of the sixth heat exchanger.

[0132] The pipeline between the cold storage oil tank and the heat storage oil tank is an oil pipeline, which is at least partially arranged on (or in) the air cooler, and is used for reducing the temperature of CO2 in the pipeline.

[0133] Please refer to the accompanying drawings Figure 1 In a specific embodiment of the embodiment, the carbon dioxide cycle energy storage system further comprises a fourth pump, a cold storage water tank, an evaporator, a first throttling valve, a second ejector, a first gas-liquid separator, and a fourth compressor.

[0134] The cold storage water tank is connected with the inlet end of the heat exchange pipe of the first heat exchanger, the inlet end of the heat exchange pipe of the second heat exchanger, and the inlet end of the heat exchange pipe of the third heat exchanger through the fourth pump, and the heat exchange medium thereof is water.

[0135] The evaporator comprises a first inner pipe and a second inner pipe.

[0136] The outlet of the heat exchange pipe of the first heat exchanger, the outlet of the heat exchange pipe of the third heat exchanger, and the outlet of the heat exchange pipe of the third heat exchanger are all in communication with the first inner pipe of the evaporator; the outlet of the first inner pipe of the evaporator is connected with the inlet of the cold storage water tank; one end of the second inner pipe of the evaporator is connected with the secondary flow inlet of the second ejector, and the other end is connected with the liquid outlet of the first gas-liquid separator through the first throttling valve.

[0137] The outlet of the second ejector is connected with the inlet of the first gas-liquid separator.

[0138] The gas outlet of the first gas-liquid separator is connected with the inlet of the fourth compressor, the outlet of the fourth compressor is connected with the inlet of the air cooler, and the outlet of the condenser is connected with the inlet of the second ejector.

[0139] In the application, the ejector (second ejector) is introduced into the heat pump system, the flow rate of the working medium in the evaporator is increased by the injection effect, the heat exchange coefficient is strengthened, the power consumption of the compressor is reduced, the entropy increase loss of the throttling process is converted into effective work, and the energy efficiency ceiling of the traditional heat pump is broken through.

[0140] In the energy storage process, the compression heat generated in the compression process of carbon dioxide is used to vaporize the low-pressure carbon dioxide at the outlet of the first throttle valve in the evaporator, and the cold energy generated by heat exchange is returned to the heat exchanger to reduce the temperature of the supercritical carbon dioxide at the outlet of each stage compressor; in the energy release process, the compression heat stored in the heat storage oil tank is used to increase the temperature of the high-pressure carbon dioxide entering the inlet of the expander, and the cold energy generated by the heat exchanger is stored in the cold storage oil tank for the cooling effect of the air cooler.

[0141] Specifically, the first ejector is used to realize split-flow composite energy release in the energy release process, and a part of the high-pressure CO2 in the tank is directly used for power generation, and the other part is used to inject the low-pressure CO2 at the outlet of the expander, thereby improving the power generation efficiency of the expander.

[0142] The second ejector is used to increase the temperature of the CO2 heat pump in the energy storage process, and the high-pressure CO2 at the outlet of the air cooler is used as the injection fluid to inject the low-pressure CO2 at the outlet of the evaporator, so that momentum exchange is realized in the mixing chamber of the ejector, the pressure on the evaporation side is increased, and the compression power consumption is reduced.

[0143] The third ejector is used to reduce the condensation temperature of CO2 in the energy release process, so that CO2 is more easily condensed and liquefied, the energy consumption is reduced, and the liquefaction efficiency is improved.

[0144] In a specific embodiment of the present embodiment, the expander is a steam turbine.

[0145] Specifically, please refer to the accompanying drawings Figure 1 In the energy storage stage, the low-pressure liquid CO2 stored in the low-pressure liquid CO2 storage tank is heated by the first methanol heat exchanger to become a critical state; then, after multi-stage compression and inter-stage cooling by the first compressor, the first heat exchanger, the second compressor, the second heat exchanger, the third compressor and the third heat exchanger, supercritical high-pressure CO2 is formed, and then after condensation by the condenser, the temperature is reduced and liquefied to form liquid CO2, which is stored in the high-pressure liquid CO2 storage tank.

[0146] In the energy storage stage, the cold energy generated in the CO2 vaporization process is stored in the low-temperature methanol tank, that is, the methanol in the high-temperature methanol tank is flowed into the low-temperature methanol tank after the heat contained therein is absorbed by CO2 when flowing through the first methanol heat exchanger; in the energy release stage, the cold energy stored in the low-temperature methanol tank is used to liquefy the CO2 at the outlet of the third ejector (during which the multi-stage cascade refrigeration unit provides cold energy to the methanol in the low-temperature methanol tank for temperature reduction).

[0147] In the energy storage process, the compression heat generated in the compression process of CO2 is used to vaporize the low-pressure CO2 at the outlet of the first throttle valve in the evaporator, and the cold generated by the heat exchange is returned to the heat exchanger (first to third heat exchangers) to reduce the temperature of the supercritical carbon dioxide at the outlet of each stage of compressor (first to third compressors); in the energy release process, the compression heat stored in the heat storage oil tank is used to increase the temperature of the high-pressure CO2 entering the inlet of the turbine, and the cold generated by the heat exchanger (fourth to sixth heat exchangers) is stored in the cold storage oil tank for the cooling effect of the air cooler.

[0148] In the energy storage process, the high-pressure CO2 enters the nozzle of the second ejector after passing through the air cooler, the speed is increased, and the pressure is reduced, so that the CO2 vapor in the evaporator enters the mixing chamber of the second ejector, the pressure rises, and the speed decreases, and then the CO2 enters the first gas-liquid separator, the liquid CO2 enters the evaporator by reducing the pressure through the first throttle valve, and the gaseous CO2 enters the compressor for recycling.

[0149] In the energy storage stage, the water in the cold storage water tank absorbs the heat of CO2 when passing through the first heat exchanger, the second heat exchanger and the third heat exchanger, and the temperature of the (heat exchange) water is increased. After being cooled by the evaporator (second ejector and other components), it flows back to the cold storage water tank.

[0150] Specifically, please refer to the accompanying drawings Figure 1 In the energy release stage, the high-pressure liquid CO2 stored in the high-pressure liquid CO2 storage tank is pumped by the first pump (pressurized) to raise the liquid CO2 to high-pressure liquid CO2 and divide it into two streams, which are injected into the first ejector from the inlet of the first ejector and the secondary flow inlet in the direct pipeline and secondary flow pipeline, respectively, through the connecting pipeline, and then injected and stored in the low-pressure liquid CO2 storage tank.

[0151] Specifically, a part (direct pipeline) is heated by the first preheater to vaporize the high-pressure liquid CO2 to a supercritical state and enter the first ejector, and then undergoes multi-stage expansion and inter-stage heating, and uses CO2 to drive the turbine to do work and generate electric energy; then the low-pressure CO2 enters the third ejector as the main flow of the ejector; the low-pressure CO2 in the second gas-liquid separator is injected into the third ejector as the secondary flow, and the two streams are mixed into low-pressure CO2 in the mixing chamber of the third ejector, and then the mixed low-pressure CO2 is liquefied by the second methanol heat exchanger, and then enters the second gas-liquid separator by reducing the pressure through the second throttle valve. The low-pressure liquid carbon dioxide is stored in the low-pressure liquid CO2 storage tank and waits for the next cycle.

[0152] In the energy release stage, the temperature is reduced by absorbing heat through the first pre-cooler and the second pre-cooler; the temperature is increased by absorbing heat through the first pre-heater and the second pre-heater;

[0153] In the energy release stage, the high-pressure liquid CO2 is preheated by the second preheater, enters the heater to absorb heat, and then enters the first expander to do work; the CO2 at the outlet of the first expander enters the heater to absorb heat again, and then enters the second expander to do work; then the CO2 is divided into two streams, one part enters the second pre-cooler (heat exchange with the second preheater), and then enters the first ejector; the other part is sequentially heated by the high-temperature regenerator and the low-temperature regenerator, and the CO2 at the outlet of the low-temperature regenerator is then divided into two parts, one part enters the re-compressor for compression, and the other part enters the main compressor for compression after being cooled by the first pre-cooler, and then enters the low-temperature regenerator to increase the temperature; then the two parts of working medium are combined and enter the high-temperature regenerator to increase the temperature, and finally enter the heater to absorb heat again, thereby completing the entire cycle process.

[0154] In the energy release stage, the high-pressure liquid CO2 is preheated by the second preheater, enters the heater to absorb heat, and then enters the first expander to do work; the CO2 at the outlet of the first expander enters the heater to absorb heat again, and then enters the second expander to do work; then the CO2 is divided into two streams, one part enters the second pre-cooler (heat exchange with the second preheater), and then enters the first ejector; the other part is sequentially heated by the high-temperature regenerator and the low-temperature regenerator, and the CO2 at the outlet of the low-temperature regenerator is then divided into two parts, one part enters the re-compressor for compression, and the other part enters the main compressor for compression after being cooled by the first pre-cooler, and then enters the low-temperature regenerator to increase the temperature; then the two parts of working medium are combined and enter the high-temperature regenerator to increase the temperature, and finally enter the heater to absorb heat again, thereby completing the entire cycle process.

[0155] In the energy release stage, the high-pressure liquid CO2 is preheated by the second preheater, enters the heater to absorb heat, and then enters the first expander to do work; the CO2 at the outlet of the first expander enters the heater to absorb heat again, and then enters the second expander to do work; then the CO2 is divided into two streams, one part enters the second pre-cooler (heat exchange with the second preheater), and then enters the first ejector; the other part is sequentially heated by the high-temperature regenerator and the low-temperature regenerator, and the CO2 at the outlet of the low-temperature regenerator is then divided into two parts, one part enters the re-compressor for compression, and the other part enters the main compressor for compression after being cooled by the first pre-cooler, and then enters the low-temperature regenerator to increase the temperature; then the two parts of working medium are combined and enter the high-temperature regenerator to increase the temperature, and finally enter the heater to absorb heat again, thereby completing the entire cycle process.

[0156] In the energy release stage, the high-pressure liquid CO2 is preheated by the second preheater, enters the heater to absorb heat, and then enters the first expander to do work; the CO2 at the outlet of the first expander enters the heater to absorb heat again, and then enters the second expander to do work; then the CO2 is divided into two streams, one part enters the second pre-cooler (heat exchange with the second preheater), and then enters the first ejector; the other part is sequentially heated by the high-temperature regenerator and the low-temperature regenerator, and the CO2 at the outlet of the low-temperature regenerator is then divided into two parts, one part enters the re-compressor for compression, and the other part enters the main compressor for compression after being cooled by the first pre-cooler, and then enters the low-temperature regenerator to increase the temperature; then the two parts of working medium are combined and enter the high-temperature regenerator to increase the temperature, and finally enter the heater to absorb heat again, thereby completing the entire cycle process.

[0157] The above only describes the preferred embodiments of the present application, and is not intended to limit the present application in any form. Although the present application has been disclosed as above, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above-mentioned technical content without departing from the technical solution of the present application, and the equivalent embodiments of the equivalent changes are equivalent. The embodiments in the above examples can be further combined or replaced, but as long as it does not deviate from the technical solution of the present application, any simple modification, equivalent change and modification of the above examples according to the technical essence of the present application are still within the scope of the present application.

Claims

1. A carbon dioxide cycle energy storage system comprising an energy storage circuit that converts low-pressure liquid CO2 into high-pressure liquid CO2 and stores it in a high-pressure liquid CO2 storage tank, and an energy release circuit that converts high-pressure liquid CO2 into low-pressure liquid CO2 and stores it in a low-pressure liquid CO2 storage tank, characterized in that: The energy releasing pipeline and the energy storing pipeline are communicated or cut off by the control valve; The energy releasing pipeline is provided with a first ejector, a first generator and a second generator; The energy releasing pipeline comprises a direct pipeline, a secondary flow pipeline and a connecting pipeline; the high-pressure liquid CO2 storage tank is connected with the inlet of the first ejector through the direct pipeline, and is connected with the secondary flow inlet of the first ejector through the secondary flow pipeline; one end of the connecting pipeline is connected with the outlet of the first ejector, and the high-pressure liquid CO2 storage tank is connected with the inlet of the low-pressure liquid CO2 storage tank through the connecting pipeline; The first generator is arranged on the secondary flow pipeline; The second generator is arranged on the connecting pipeline.

2. A carbon dioxide cycle energy storage system according to claim 1, wherein, The energy storing pipeline is provided with a first methanol heat exchanger, a first compressor, a first heat exchanger, a second compressor, a second heat exchanger, a third compressor, a third heat exchanger and a condenser which are connected in sequence; The inlet of the outer pipe of the first methanol heat exchanger is connected with the outlet of the low-pressure liquid CO2 storage tank, and the outlet of the outer pipe of the first methanol heat exchanger is communicated with the inlet of the first compressor; The outlet of the first compressor is connected with the inlet of the outer pipe of the first heat exchanger, and the outlet of the outer pipe of the third heat exchanger is connected with the inlet of the condenser; The first compressor, the second compressor and the third compressor are driven by the same motor.

3. A carbon dioxide cycle energy storage system according to claim 1 or 2, wherein, One end of the energy releasing pipeline is communicated with the outlet of the high-pressure liquid CO2 storage tank, and the other end is communicated with the inlet of the low-pressure liquid CO2 storage tank; The direct pipeline and the secondary flow pipeline are connected with the outlet of the high-pressure liquid CO2 storage tank at one end close to the high-pressure liquid CO2 storage tank; the outlet end of the high-pressure liquid CO2 storage tank is provided with a first pump which controls the delivery of high-pressure liquid CO2 in the high-pressure liquid CO2 storage tank to the direct pipeline and / or the indirect pipeline; The connecting pipeline is provided with a fourth heat exchanger, a third expander, a fifth heat exchanger, a fourth expander, a sixth heat exchanger, a fifth expander and a third ejector which are communicated in sequence; the outlet of the first ejector is connected with the inlet of the outer pipe of the fourth heat exchanger, and the outlet of the fifth expander is communicated with the inlet of the third ejector; The direct pipeline is provided with a first preheater, and one end of the direct pipeline away from the outlet of the high-pressure liquid CO2 storage tank is provided with a first branch pipe and a second branch pipe; The first branch pipe is provided with a first valve, and the first branch pipe is connected with the inlet of the first ejector; the second branch pipe is provided with a second valve, and the second branch pipe is connected with the inlet of the outer pipe of the fourth heat exchanger.

4. A carbon dioxide cycle energy storage system according to claim 3, wherein, The third expander, the fourth expander and the fifth expander jointly drive the second generator.

5. A carbon dioxide cycle energy storage system according to claim 3, wherein, The connecting pipeline is further provided with a second methanol heat exchanger, a second throttling valve and a second gas-liquid separator which are communicated in sequence; The outlet of the third ejector is connected with the inlet of the outer pipe of the second methanol heat exchanger; The outlet of the third ejector is connected with the inlet of the outer pipe of the second methanol heat exchanger; An outlet of an outer pipe of the second methanol heat exchanger is connected with the second throttle valve; An outlet of an outer pipe of the second gas-liquid separator is communicated with an inlet of the low-pressure liquid CO2 storage tank, and an outlet of the second gas-liquid separator is connected with a secondary flow inlet of the third ejector.

6. A carbon dioxide cycle energy storage system according to claim 5, wherein, The carbon dioxide cycle energy storage system further comprises a high-temperature methanol tank and a low-temperature methanol tank, an outlet end of the high-temperature methanol tank is connected with an inlet of the heat exchange pipe of the first methanol heat exchanger, and an inlet end of the high-temperature methanol tank is connected with an outlet end of the heat exchange pipe of the second methanol heat exchanger; An inlet end of the low-temperature methanol tank is connected with an outlet end of the heat exchange pipe of the first methanol heat exchanger, and an outlet end of the low-temperature methanol tank is connected with an inlet end of the heat exchange pipe of the second methanol heat exchanger.

7. A carbon dioxide cycle energy storage system according to claim 6, wherein, The carbon dioxide cycle energy storage system further comprises a third pump and a cascade refrigeration unit, and the cascade refrigeration unit controls the temperature of the low-temperature methanol tank; A heat exchange medium in the cascade refrigeration unit is heat exchange oil.

8. A carbon dioxide cycle energy storage system according to claim 3, wherein, A third valve, a second preheater, a heater, a first expander, a second expander, a second pre-cooler, a high-temperature regenerator, a low-temperature regenerator, a re-compressor, a first pre-cooler and a main compressor are arranged on the indirect pipeline; An outer pipe of the second preheater is communicated with a pipe of the heater; An outlet of the first expander is communicated with an inlet of a second pipe of the heater, and an outlet of the second pipe of the heater is connected with an inlet of the second expander; The second expander comprises a first outlet and a second outlet, the first outlet of the second expander is connected with an inlet of an outer pipe of the second pre-cooler, and the second outlet of the second expander is connected with the high-temperature regenerator; A heat exchange pipe of the second preheater is communicated with a heat exchange pipe of the second pre-cooler, and a heat exchange medium in the heat exchange pipe is methanol; An outlet of an outer pipe of the second pre-cooler is connected with a secondary flow inlet of the first ejector; The high-temperature regenerator comprises a first outlet and a second outlet, the first outlet of the high-temperature regenerator is connected with a pipe of the heater, and the second outlet of the high-temperature regenerator is communicated with an inlet of the low-temperature regenerator; The low-temperature regenerator comprises a first outlet, a second outlet and a third outlet, the first outlet of the low-temperature regenerator is connected with the high-temperature regenerator, the second outlet of the low-temperature regenerator is connected with the re-compressor, and the third outlet of the low-temperature regenerator is connected with an inlet of an outer pipe of the first pre-cooler; An outlet of an outer pipe of the first pre-cooler is connected with the main compressor; The re-compressor is connected with the high-temperature regenerator; The main compressor is connected with the low-temperature regenerator; A heat exchange pipe of the first pre-cooler is connected with a heat exchange pipe of the second preheater, and a heat exchange medium in the heat exchange pipe is methanol.

9. The carbon dioxide cycle energy storage system of claim 1, wherein, The carbon dioxide cycle energy storage system further comprises an air cooler, a heat storage oil tank, a fifth pump and a cold storage oil tank; The cold storage oil tank is used for adjusting the temperature of the air cooler, and a heat exchange medium in the cold storage oil tank is heat exchange oil; Outlet ends of heat exchange pipes of the fourth heat exchanger, the fifth heat exchanger and the sixth heat exchanger are communicated with an inlet end of the cold storage oil tank, and an outlet end of the cold storage oil tank is communicated with an inlet end of the heat storage oil tank. The outlet end of the heat storage oil tank is connected with the inlet end of the heat exchange pipe of the fourth heat exchanger, the inlet end of the heat exchange pipe of the fifth heat exchanger and the inlet end of the heat exchange pipe of the sixth heat exchanger.

10. A carbon dioxide cycle energy storage system according to claim 9, wherein, The carbon dioxide cycle energy storage system further comprises a fourth pump, a cold storage water tank, an evaporator, a first throttling valve, a second ejector, a first gas-liquid separator and a fourth compressor. The cold storage water tank is connected with the inlet end of the heat exchange pipe of the first heat exchanger, the inlet end of the heat exchange pipe of the second heat exchanger and the inlet end of the heat exchange pipe of the third heat exchanger through the fourth pump, and the heat exchange medium thereof is water. The evaporator comprises a first inner pipe and a second inner pipe; the outlet of the heat exchange pipe of the first heat exchanger, the outlet of the heat exchange pipe of the third heat exchanger and the outlet of the heat exchange pipe of the third heat exchanger are all communicated with the inlet of the first inner pipe of the evaporator; the outlet of the first inner pipe of the evaporator is connected with the inlet of the cold storage water tank; one end of the second inner pipe of the evaporator is connected with the secondary flow inlet of the second ejector, and the other end is connected with the liquid outlet of the first gas-liquid separator through the first throttling valve; The outlet of the second ejector is connected with the inlet of the first gas-liquid separator; The gas outlet of the first gas-liquid separator is connected with the inlet of the fourth compressor, the outlet of the fourth compressor is connected with the inlet of the gas cooler, and the outlet of the condenser is connected with the inlet of the second ejector.

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