A multi-phase-state high-efficiency solid-state carbon dioxide energy storage system and a control method thereof

Abstract

The application discloses a multi-phase state efficient solid carbon dioxide energy storage system and a control method thereof. The application realizes energy storage and release through the expansion of liquid carbon dioxide in the energy storage stage to be converted into solid carbon dioxide for storage, and the conversion of solid carbon dioxide in the energy release stage into high-pressure liquid carbon dioxide to drive a gaseous drive generator. The application solves the disadvantages of low energy storage density and high energy loss of traditional energy storage, and provides a forward-looking solution for carbon capture, energy storage and multi-scene application. The application provides strong support for the efficient development of the global energy industry. After the energy release, the carbon dioxide is liquefied through recovery and compression, and returns to the energy release stage entrance of the liquid storage tank, realizing the closed-loop circulation of carbon dioxide between liquid, solid and liquid states, and achieving efficient operation. The application uses solid carbon dioxide as an energy storage medium, realizes efficient conversion and circulation of energy, and has the advantages of simple system structure, low operation cost and high energy utilization rate.

Description

TECHNICAL FIELD

[0001] The present application relates to energy storage technology, in particular to a multi-phase state efficient solid carbon dioxide energy storage system and its control method. BACKGROUND

[0002] Solid carbon dioxide energy storage technology provides a new way of thinking for the energy storage industry: improving energy storage density and safety through physical phase change. This technological breakthrough is expected to break the current over-reliance on lithium-ion batteries in the energy storage market and promote the development of a more diversified and sustainable energy storage industry. Compatible with renewable energy storage needs. The present application is suitable for the storage and release of intermittent renewable energy such as wind and solar energy. Through the long-term stable storage characteristics of solid carbon dioxide, the volatility of renewable energy generation can be effectively balanced. The existing technology for carbon dioxide energy storage also focuses on the conversion between gaseous and liquid states, and has not fully utilized the high energy density and stable storage characteristics of solid carbon dioxide, so there are still deficiencies in energy storage density, system stability and energy efficiency. In particular, in the control of phase change and the utilization of multiple phases, the traditional technology lacks precise control mechanisms, which easily leads to energy loss and system efficiency reduction. SUMMARY

[0003] To solve the problems of low energy utilization efficiency, poor system stability and limited energy storage density in the prior art, the present application proposes a multi-phase state efficient solid carbon dioxide energy storage system and its control method, aiming to realize efficient phase change of liquid carbon dioxide into solid state to improve energy storage density, and to improve the overall energy efficiency and stability of the system through multi-stage heat exchange control, phase change regulation and closed-loop recovery path.

[0004] One object of the present application is to provide a multi-phase state efficient solid carbon dioxide energy storage system.

[0005] The multi-phase state efficient solid carbon dioxide energy storage system of the present application comprises: a liquid storage tank, a first hydraulic pump, a second hydraulic pump, a throttling expansion valve, a solid storage tank, a first heating heat exchanger, a second heating heat exchanger, a compressor, a first cooling heat exchanger, a second cooling heat exchanger, a gaseous drive generator, a first high-temperature liquid storage tank, a second high-temperature liquid storage tank, a first low-temperature liquid storage tank and a second low-temperature liquid storage tank; wherein,

[0006] The energy storage stage outlet of the liquid storage tank is connected to the first hydraulic pump through a pipeline, the first hydraulic pump is connected to the energy storage stage inlet of the solid storage tank through a pipeline, and a throttling expansion valve is arranged at the energy storage stage inlet of the solid storage tank; a first switch valve is arranged at the energy storage stage outlet of the solid storage tank, the energy storage stage outlet of the solid storage tank is connected to the carbon dioxide inlet of the first temperature-increasing heat exchanger through a pipeline, the carbon dioxide inlet and the carbon dioxide outlet of the first temperature-increasing heat exchanger are connected through a carbon dioxide connecting pipeline; the carbon dioxide outlet of the first temperature-increasing heat exchanger is connected to the inlet of the compressor through a pipeline; the outlet of the compressor is connected to the carbon dioxide inlet of the first temperature-decreasing heat exchanger through a pipeline, the carbon dioxide inlet and the carbon dioxide outlet of the first temperature-decreasing heat exchanger are connected through a carbon dioxide connecting pipeline; the carbon dioxide outlet of the first temperature-decreasing heat exchanger is connected to the energy storage stage inlet of the liquid storage tank through a pipeline, thereby forming an energy storage circulating pipeline, and the working medium in the energy storage circulating pipeline is carbon dioxide;

[0007] The energy storage stage outlet of the liquid storage tank is connected to the first hydraulic pump through a pipeline, the first hydraulic pump is connected to the energy storage stage inlet of the solid storage tank through a pipeline, and a throttling expansion valve is arranged at the energy storage stage inlet of the solid storage tank; a first switch valve is arranged at the energy storage stage outlet of the solid storage tank, the energy storage stage outlet of the solid storage tank is connected to the carbon dioxide inlet of the first temperature-increasing heat exchanger through a pipeline, the carbon dioxide inlet and the carbon dioxide outlet of the first temperature-increasing heat exchanger are connected through a carbon dioxide connecting pipeline; the carbon dioxide outlet of the first temperature-increasing heat exchanger is connected to the gas inlet of the gaseous drive generator through a pipeline; the gas outlet of the gaseous drive generator is connected to the carbon dioxide inlet of the second temperature-decreasing heat exchanger through a pipeline, the carbon dioxide inlet and the carbon dioxide outlet of the second temperature-decreasing heat exchanger are connected through a carbon dioxide connecting pipeline; the carbon dioxide outlet of the second temperature-decreasing heat exchanger is connected to the energy storage stage inlet of the liquid storage tank through a pipeline, thereby forming an energy storage circulating pipeline, and the working medium in the energy storage circulating pipeline is carbon dioxide;

[0008] A first high-temperature liquid storage tank outlet valve is arranged at the outlet of the first high-temperature liquid storage tank, the outlet of the first high-temperature liquid storage tank is connected to the heat exchange working medium inlet of the first temperature-increasing heat exchanger through a pipeline, the heat exchange working medium inlet and the heat exchange working medium outlet of the first temperature-increasing heat exchanger are connected through a heat exchange working medium connecting pipeline; the heat exchange working medium outlet of the first temperature-increasing heat exchanger is connected to the inlet of the first low-temperature liquid storage tank through a pipeline; the outlet of the first low-temperature liquid storage tank is connected to the heat exchange working medium inlet of the first temperature-decreasing heat exchanger through a pipeline, the heat exchange working medium inlet and the heat exchange working medium outlet of the first temperature-decreasing heat exchanger are connected through a heat exchange working medium connecting pipeline; the heat exchange working medium outlet of the first temperature-decreasing heat exchanger is connected to the inlet of the first high-temperature liquid storage tank through a pipeline, thereby forming a first auxiliary heat exchange circulating pipeline; the heat exchange working medium connecting pipeline and the carbon dioxide connecting pipeline of the first temperature-increasing heat exchanger are not connected; the heat exchange working medium connecting pipeline and the carbon dioxide connecting pipeline of the first temperature-decreasing heat exchanger are not connected;

[0009] A second high-temperature liquid storage tank outlet valve is arranged at the outlet of the second high-temperature liquid storage tank, the outlet of the second high-temperature liquid storage tank is connected to the heat exchange working medium inlet of the second temperature-increasing heat exchanger through a pipeline, the heat exchange working medium inlet and the heat exchange working medium outlet of the second temperature-increasing heat exchanger are communicated through a heat exchange working medium connecting pipe; the heat exchange working medium outlet of the second temperature-increasing heat exchanger is connected to the inlet of the second low-temperature liquid storage tank through a pipeline; the outlet of the second low-temperature liquid storage tank is connected to the heat exchange working medium inlet of the second temperature-decreasing heat exchanger through a pipeline, the heat exchange working medium inlet and the heat exchange working medium outlet of the second temperature-decreasing heat exchanger are communicated through a heat exchange working medium connecting pipe; the heat exchange working medium outlet of the second temperature-decreasing heat exchanger is connected to the inlet of the second high-temperature liquid storage tank through a pipeline, forming a second auxiliary heat exchange circulation pipeline; the heat exchange working medium connecting pipe of the second temperature-increasing heat exchanger and the carbon dioxide connecting pipe are not communicated; the heat exchange working medium connecting pipe of the second temperature-decreasing heat exchanger and the carbon dioxide connecting pipe are not communicated.

[0010] The first switch valve at the outlet of the energy storage stage of the solid-state storage tank adopts a gas valve. The second switch valve at the outlet of the energy release stage of the solid-state storage tank adopts a liquid valve.

[0011] The first and second temperature-increasing heat exchangers adopt heat exchangers for heat exchange between liquid and gas or liquid. The first and second temperature-decreasing heat exchangers adopt heat exchangers for heat exchange between liquid and gas or liquid.

[0012] The first and second temperature-decreasing heat exchangers adopt multi-stage serial heat exchangers for step-by-step temperature decrease, ensuring that the energy loss of the carbon dioxide after energy release in the cooling process is less than 5%. The first and second temperature-increasing heat exchangers adopt multi-stage serial heat exchangers for step-by-step temperature increase.

[0013] The working medium in the first and second auxiliary heat exchange circulation pipelines is liquid working medium, which is water, salt solution or organic solvent that always remains in liquid state without phase change in the temperature range of work.

[0014] The outlet nozzle of the throttling expansion valve is located on the inner wall of the solid-state storage tank, and the diameter of the outlet nozzle of the throttling expansion valve ranges from 0.1 to 70 mm; the actual needs are adjusted to adapt to different flow requirements, and the expansion efficiency is above 70%.

[0015] The solid-state storage tank adopts a double-layer heat insulation design, the inner layer is a low-temperature resistant material, and the outer layer is a vacuum insulation layer, the pressure range is 0.1-12 MPa, and a multi-point temperature and pressure monitoring device is provided.

[0016] The gaseous drive generator is a turbine. The inlet of the gaseous drive generator is provided with a heat exchange device, and the high-pressure carbon dioxide is heated to 100-200℃ by using industrial waste heat or solar energy to improve the power generation efficiency.

[0017] A modular design is adopted, and the size of the storage tank, the injection expansion device and the turbine power generation device can be adjusted according to the application requirements to adapt to 1-100 m 3Volume range.

[0018] Further, the application also includes temperature sensors and force sensors arranged on the first and second switch valves to monitor the temperature and pressure of the closed high-pressure storage tank during the energy storage and energy release stages, respectively. The application further includes a gas-liquid separation device arranged on the inner wall of the solid-state storage tank at the energy storage stage outlet, which retains the solid-state carbon dioxide in the solid-state storage tank, and the gaseous carbon dioxide is discharged from the energy storage stage outlet through the gas-liquid separation device. The gas-liquid separation device uses a filter.

[0019] It also includes an energy storage stage inlet switch valve and an energy release stage inlet switch valve arranged before entering the energy storage stage inlet and the energy release stage inlet, respectively. The energy storage stage opens the energy storage stage inlet switch valve and closes the energy release stage inlet switch valve, and the energy release stage opens the energy release stage inlet switch valve and closes the energy storage stage inlet switch valve.

[0020] The pipeline uses high-pressure temperature-resistant materials to ensure the safe transmission of liquid and gaseous carbon dioxide. Multiple sets of control valves and flow regulating devices are arranged in the pipeline to accurately control the flow and phase change process of carbon dioxide, ensuring the stable operation of the system.

[0021] Another object of the application is to provide a control method for a multi-phase high-efficiency solid-state carbon dioxide energy storage system.

[0022] The control method for the multi-phase high-efficiency solid-state carbon dioxide energy storage system of the application includes the following steps:

[0023] 1) Energy storage stage:

[0024] a. Open the first hydraulic pump and close the second hydraulic pump; open the first switch valve and close the second switch valve;

[0025] b. Liquid carbon dioxide is stored in the liquid storage tank, and the energy storage stage outlet of the liquid storage tank outputs liquid carbon dioxide which is pressurized by the first hydraulic pump and delivered to the throttling expansion valve;

[0026] c. The liquid carbon dioxide is rapidly depressurized and cooled in the throttling expansion valve, and the liquid carbon dioxide is injected into the energy storage stage inlet of the solid-state storage tank through the throttling expansion valve, forming solid-state carbon dioxide and a small amount of gaseous carbon dioxide in the solid-state storage tank, and realizing phase change in the solid-state storage tank;

[0027] d. The solid-state carbon dioxide is directly collected and stored in the solid-state storage tank, and the gaseous carbon dioxide enters the carbon dioxide connection pipe of the first heating heat exchanger through the energy storage stage outlet, exchanges heat with the heat exchange medium in the heat exchange medium connection pipe, and the temperature rises, and is delivered to the compressor;

[0028] e. The gaseous carbon dioxide passing through the compressor is increased in pressure and temperature, and is delivered to the carbon dioxide connecting pipe of the first cooling device to exchange heat with the heat exchange medium in the heat exchange medium connecting pipe, and the temperature is reduced to the liquefaction condition;

[0029] f. The liquid carbon dioxide is returned to the liquid storage tank. Through the compression and cooling design, the compression energy consumption is effectively reduced, and the overall efficiency of the system is significantly improved;

[0030] The energy storage stage stores the liquid carbon dioxide in the solid state carbon dioxide storage tank by converting it into solid state carbon dioxide;

[0031] 2) Energy release and recovery stage:

[0032] a. Open the second hydraulic pump and close the first hydraulic pump; open the second switch valve and close the first switch valve;

[0033] b. The liquid carbon dioxide from the energy release stage outlet of the liquid storage tank is increased in pressure by the second hydraulic pump; the high-pressure liquid carbon dioxide is injected into the energy release stage inlet of the solid state storage tank, causing the solid state carbon dioxide to warm up and partially phase change, further providing conditions for the generation of high-pressure carbon dioxide; the mixed carbon dioxide in solid, liquid and gaseous states is ejected from the energy release stage outlet of the solid state storage tank to the carbon dioxide connecting pipe of the second heating heat exchanger;

[0034] c. The mixed carbon dioxide in solid, liquid and gaseous states exchanges heat with the heat exchange medium in the heat exchange medium connecting pipe in the carbon dioxide connecting pipe of the second heating heat exchanger, and is preheated or assisted to further increase its enthalpy value, and is converted into high-pressure gaseous carbon dioxide, and the generated high-pressure gaseous carbon dioxide provides sufficient energy for turbine power generation; d. The high-pressure gaseous carbon dioxide is delivered to the gaseous drive generator, and the gaseous carbon dioxide drives the turbine to rotate, converting the pressure energy and thermal energy of the gas into mechanical energy, and outputting electric energy through the gaseous drive generator;

[0035] e. The gaseous carbon dioxide passing through the gaseous drive generator is cooled by the second cooling heat exchanger to become liquid carbon dioxide and is returned to the energy release stage inlet of the liquid storage tank for recycling;

[0036] The energy release process converts the solid state carbon dioxide into high-pressure gaseous carbon dioxide to drive the gaseous drive generator to generate electricity, and completes the energy release;

[0037] 3) Auxiliary heat exchange:

[0038] a. Energy storage stage: open the first high-temperature liquid tank outlet valve; the heat transfer medium of the first high-temperature liquid tank is transported to the heat transfer medium connecting pipe of the first temperature-increasing heat exchanger to heat the gaseous carbon dioxide in the carbon dioxide connecting pipe, the temperature of the heat transfer medium in the heat transfer medium connecting pipe of the first temperature-increasing heat exchanger decreases, and is transported to the first low-temperature liquid tank; the heat transfer medium with reduced temperature is transported to the heat transfer medium connecting pipe of the first temperature-decreasing heat exchanger to cool the gaseous carbon dioxide in the carbon dioxide connecting pipe, and the temperature of the heat transfer medium increases to return to the first high-temperature liquid tank;

[0039] b. Energy release stage: open the second high-temperature liquid tank outlet valve; the heat transfer medium of the second high-temperature liquid tank is transported to the heat transfer medium connecting pipe of the second temperature-increasing heat exchanger to heat the gaseous carbon dioxide in the carbon dioxide connecting pipe, the temperature of the heat transfer medium in the heat transfer medium connecting pipe of the second temperature-increasing heat exchanger decreases, and is transported to the second low-temperature liquid tank; the heat transfer medium with reduced temperature is transported to the heat transfer medium connecting pipe of the second temperature-decreasing heat exchanger to cool the gaseous carbon dioxide in the carbon dioxide connecting pipe, and the temperature of the heat transfer medium increases to return to the second high-temperature liquid tank.

[0040] In a. of step 1), the working conditions of the liquid tank are low temperature and high pressure, which ensure that the liquid carbon dioxide is in a stable state. The pressure of the liquid carbon dioxide passing through the first hydraulic pump is 4-7 MPa.

[0041] In c. of step 1), the density of solid carbon dioxide is high, which has a significant energy storage advantage compared to liquid or gaseous forms. The liquid carbon dioxide is rapidly depressurized to an outlet pressure range of 0.4-0.6 MPa in the throttling expansion valve; the temperature is reduced to the triple point of carbon dioxide, -56.6°C.

[0042] The core of the energy storage stage is to achieve solid-state storage through the rapid expansion of liquid carbon dioxide, and the entire process does not require complex cooling equipment, significantly reducing the energy consumption and operating cost of the system. The solid-state tank can support long-term stable storage without additional energy input, significantly improving the safety and reliability of the energy storage system.

[0043] In a. of step 2), the pressure through the second hydraulic pump is 6-12 MPa.

[0044] In b. of step 2), the mixing ratio of liquid and solid carbon dioxide is dynamically adjusted by the second hydraulic pump to be 1:1-10:1, and the specific ratio is adjusted according to the real-time energy release demand.

[0045] In d. of step 2), a heat exchange device is arranged at the inlet of the gaseous drive generator, and the gaseous carbon dioxide is heated by using the low-grade heat source of industrial waste heat or solar energy to make the gas temperature reach the optimal power generation condition, thereby significantly improving the power generation efficiency of the gaseous drive generator. This process not only releases energy, but also ensures efficient use of carbon dioxide.

[0046] In e. of step 2), the liquefied carbon dioxide is stored in the liquid storage tank again for subsequent energy storage cycle; through compression and cooling design, the compression energy consumption is effectively reduced, and the overall system efficiency is significantly improved.

[0047] In step 3), the first and second high-temperature liquid storage tanks are heated by using the low-grade heat source of industrial waste heat or solar energy.

[0048] Advantages of the present application:

[0049] The present application stores and releases energy by expanding the liquid carbon dioxide into solid carbon dioxide in the energy storage stage, and converting the solid carbon dioxide into high-pressure gaseous carbon dioxide to drive the gaseous drive generator in the energy release stage. The present application uses solid carbon dioxide energy storage and liquid-solid mixed energy release technology control to solve the low energy storage density and high energy loss of traditional energy storage, and provides a forward-looking solution for carbon capture, energy storage and multi-scenario application. The breakthrough and practicality of this technology will provide strong support for the efficient development of global energy industry. The energy storage and release conversion efficiency is high, and the carbon dioxide is liquefied by recycling and compression after energy release and returned to the inlet of the energy release stage of the liquid storage tank, realizing the closed loop circulation of carbon dioxide between liquid, solid and liquid states, and making the system achieve efficient operation. The whole cycle process of the present application is designed to be efficient, safe and economical, and is an innovative solution to meet the future energy storage needs. The present application uses solid carbon dioxide as the energy storage medium to realize efficient conversion and circulation of energy, and has the advantages of simple system structure, low operation cost and high energy utilization rate. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 FIG. 1 is a schematic diagram of an embodiment of the multi-phase state efficient solid carbon dioxide energy storage system of the present application. DETAILED DESCRIPTION

[0051] The present application will be further described below in conjunction with the drawings and specific embodiments.

[0052] As Figure 1As shown, the multi-phase state high-efficiency solid-state carbon dioxide energy storage system of the embodiment includes a liquid storage tank, a first hydraulic pump, a second hydraulic pump, a throttling expansion valve, a solid-state storage tank, a first temperature-increasing heat exchanger, a second temperature-increasing heat exchanger, a compressor, a first temperature-decreasing heat exchanger, a second temperature-decreasing heat exchanger, a gaseous drive generator, a first high-temperature liquid storage tank, a second high-temperature liquid storage tank, a first low-temperature liquid storage tank, and a second low-temperature liquid storage tank; wherein,

[0053] The energy storage stage outlet of the liquid storage tank is connected to the first hydraulic pump through a pipeline, the first hydraulic pump is connected to the energy storage stage inlet of the solid-state storage tank through a pipeline, an energy storage stage inlet switch valve is arranged before the energy storage stage inlet, and a throttling expansion valve is arranged in the energy storage stage inlet; a first switch valve is arranged at the energy storage stage outlet of the solid-state storage tank, the energy storage stage outlet of the solid-state storage tank is connected to the carbon dioxide inlet of the first temperature-increasing heat exchanger through a pipeline, the carbon dioxide inlet and the carbon dioxide outlet of the first temperature-increasing heat exchanger are connected through a carbon dioxide connecting pipe; the carbon dioxide outlet of the first temperature-increasing heat exchanger is connected to the inlet of the compressor through a pipeline; the outlet of the compressor is connected to the carbon dioxide inlet of the first temperature-decreasing heat exchanger through a pipeline, the carbon dioxide inlet and the carbon dioxide outlet of the first temperature-decreasing heat exchanger are connected through a carbon dioxide connecting pipe; the carbon dioxide outlet of the first temperature-decreasing heat exchanger is connected to the energy storage stage inlet of the liquid storage tank through a pipeline, thereby forming an energy storage circulating pipeline, and the working medium in the energy storage circulating pipeline is carbon dioxide;

[0054] The energy storage stage outlet of the liquid storage tank is connected to the first hydraulic pump through a pipeline, the first hydraulic pump is connected to the energy storage stage inlet of the solid-state storage tank through a pipeline, an energy storage stage inlet switch valve is arranged before the energy storage stage inlet, and a throttling expansion valve is arranged in the energy storage stage inlet; a first switch valve is arranged at the energy storage stage outlet of the solid-state storage tank, the energy storage stage outlet of the solid-state storage tank is connected to the carbon dioxide inlet of the first temperature-increasing heat exchanger through a pipeline, the carbon dioxide inlet and the carbon dioxide outlet of the first temperature-increasing heat exchanger are connected through a carbon dioxide connecting pipe; the carbon dioxide outlet of the first temperature-increasing heat exchanger is connected to the gas inlet of the turbine through a pipeline; the gas outlet of the turbine is connected to the carbon dioxide inlet of the second temperature-decreasing heat exchanger through a pipeline, the carbon dioxide inlet and the carbon dioxide outlet of the second temperature-decreasing heat exchanger are connected through a carbon dioxide connecting pipe; the carbon dioxide outlet of the second temperature-decreasing heat exchanger is connected to the energy storage stage inlet of the liquid storage tank through a pipeline, thereby forming an energy storage circulating pipeline, and the working medium in the energy storage circulating pipeline is carbon dioxide;

[0055] A first high-temperature liquid storage tank outlet valve is arranged at the outlet of the first high-temperature liquid storage tank, the outlet of the first high-temperature liquid storage tank is connected to the heat exchange working medium inlet of the first temperature-increasing heat exchanger through a pipeline, and the heat exchange working medium inlet and the heat exchange working medium outlet of the first temperature-increasing heat exchanger are communicated through a heat exchange working medium connecting pipe; the heat exchange working medium outlet of the first temperature-increasing heat exchanger is connected to the inlet of the first low-temperature liquid storage tank through a pipeline; the outlet of the first low-temperature liquid storage tank is connected to the heat exchange working medium inlet of the first temperature-decreasing heat exchanger through a pipeline, and the heat exchange working medium inlet and the heat exchange working medium outlet of the first temperature-decreasing heat exchanger are communicated through a heat exchange working medium connecting pipe; the heat exchange working medium outlet of the first temperature-decreasing heat exchanger is connected to the inlet of the first high-temperature liquid storage tank through a pipeline, thereby forming a first auxiliary heat exchange circulation pipeline; the heat exchange working medium connecting pipe of the first temperature-increasing heat exchanger is not communicated with the carbon dioxide connecting pipe; the heat exchange working medium connecting pipe of the first temperature-decreasing heat exchanger is not communicated with the carbon dioxide connecting pipe.

[0056] A second high-temperature liquid storage tank outlet valve is arranged at the outlet of the second high-temperature liquid storage tank, the outlet of the second high-temperature liquid storage tank is connected to the heat exchange working medium inlet of the second temperature-increasing heat exchanger through a pipeline, and the heat exchange working medium inlet and the heat exchange working medium outlet of the second temperature-increasing heat exchanger are communicated through a heat exchange working medium connecting pipe; the heat exchange working medium outlet of the second temperature-increasing heat exchanger is connected to the inlet of the second low-temperature liquid storage tank through a pipeline; the outlet of the second low-temperature liquid storage tank is connected to the heat exchange working medium inlet of the second temperature-decreasing heat exchanger through a pipeline, and the heat exchange working medium inlet and the heat exchange working medium outlet of the second temperature-decreasing heat exchanger are communicated through a heat exchange working medium connecting pipe; the heat exchange working medium outlet of the second temperature-decreasing heat exchanger is connected to the inlet of the second high-temperature liquid storage tank through a pipeline, thereby forming a second auxiliary heat exchange circulation pipeline; the heat exchange working medium connecting pipe of the second temperature-increasing heat exchanger is not communicated with the carbon dioxide connecting pipe; the heat exchange working medium connecting pipe of the second temperature-decreasing heat exchanger is not communicated with the carbon dioxide connecting pipe.

[0057] The first and second temperature-decreasing heat exchangers are multi-stage serial heat exchangers, and the first and second temperature-increasing heat exchangers are multi-stage serial heat exchangers; the working medium in the first and second auxiliary heat exchange circulation pipelines is water; and the diameter of the outlet nozzle of the throttling expansion valve ranges from 0.1 mm to 0.5 mm.

[0058] The control method of the multi-phase state high-efficiency solid-state carbon dioxide energy storage system comprises the following steps:

[0059] 1) Energy storage stage:

[0060] a. open the first hydraulic pump and close the second hydraulic pump; open the first switch valve at the energy storage stage outlet of the solid-state storage tank and close the second switch valve at the energy release outlet of the solid-state storage tank; open the energy storage stage inlet switch valve and close the energy release stage inlet switch valve;

[0061] b. Liquid carbon dioxide stored in liquid storage tank, liquid storage tank energy storage stage outlet output liquid carbon dioxide through the first hydraulic pump to improve the pressure to 5 MPa, delivered to the throttle expansion valve;

[0062] c. Liquid carbon dioxide in the throttle expansion valve rapid decompression to the export pressure range is 0.5 MPa, to pressure temperature, temperature drops to about-56.6 ℃, direct conversion into solid carbon dioxide; Liquid carbon dioxide is injected to the solid state storage tank energy storage stage inlet, to the solid state storage tank, close to the carbon dioxide triple point, in the solid state storage tank forms solid carbon dioxide and a small amount of gaseous carbon dioxide, in the solid state storage tank to achieve phase change; Solid carbon dioxide has high density, compared with liquid or gaseous form has significant energy storage advantage;

[0063] d. The converted solid carbon dioxide is directly collected and stored in the solid state storage tank, for high density energy storage; The pressure of the energy storage stage outlet is controlled to be 0.4Ma~0.7MPa by the first control valve; Gaseous carbon dioxide is then sent to the carbon dioxide connecting pipe of the first heating heat exchanger, exchanges heat with the heat exchange medium in the heat exchange medium connecting pipe, and is sent to the compressor;

[0064] e. The gaseous carbon dioxide after the compressor is increased in pressure and temperature, is sent to the carbon dioxide connecting pipe of the first cooling device, exchanges heat with the heat exchange medium in the heat exchange medium connecting pipe, and is reduced in temperature to liquefaction conditions;

[0065] f. Liquid carbon dioxide returns to the liquid storage tank;

[0066] The core of the energy storage stage is to realize solid state storage through the rapid expansion of liquid carbon dioxide, the whole process does not need complex cooling equipment, greatly reduces the energy consumption and operation cost of the system; The solid carbon dioxide storage tank design can support long time stable storage, without additional energy input, significantly improves the safety and reliability of the energy storage system; The energy storage stage stores the liquid carbon dioxide converted into solid carbon dioxide in the solid state storage tank;

[0067] 2) Energy release and recovery stage:

[0068] a. Open the second hydraulic pump, close the first hydraulic pump; Open the second switch valve at the energy release outlet of the solid state storage tank, close the first switch valve at the energy storage stage outlet of the solid state storage tank; Open the energy release stage inlet switch valve, close the energy storage stage inlet switch valve;

[0069] b. Liquid carbon dioxide is pressurized at the energy-release stage outlet of the liquid storage tank via a second hydraulic pump; the high-pressure liquid carbon dioxide is injected into the energy-release stage inlet of the solid storage tank, triggering a temperature increase and partial phase change of the solid carbon dioxide. The liquid and solid carbon dioxide mix within the solid storage tank at a ratio of 1:1 to 10:1, generating high-pressure carbon dioxide. The three-phase mixture of solid, liquid, and gaseous carbon dioxide is ejected from the energy-release stage outlet of the solid storage tank to the carbon dioxide connecting pipe of the second temperature-raising heat exchanger;

[0070] c. The three-phase mixed carbon dioxide exchanges heat with the heat exchange medium in the heat exchange medium connecting pipe of the second temperature-raising heat exchanger, is heated to 100°C to 200°C, and is converted into high-pressure gaseous carbon dioxide, which then passes through the second temperature-raising heat exchanger;

[0071] d. A second heating heat exchanger at the turbine inlet ensures that the gas temperature reaches the optimal power generation conditions, significantly improving the turbine's power generation efficiency. High-pressure gaseous carbon dioxide is delivered to the turbine, where it drives the turbine, converting the gas's pressure and thermal energy into mechanical energy, which is then output as electrical energy through the turbine. This not only releases energy but also ensures the efficient use of carbon dioxide.

[0072] e. The gaseous carbon dioxide that passes through the turbine has a low density. After being cooled by the second cooling heat exchanger, it is converted into liquid carbon dioxide and returned to the energy release stage entrance of the liquid storage tank for recycling. The energy release process converts solid carbon dioxide into high-pressure gaseous carbon dioxide, which drives the gaseous drive generator to generate electricity, completing energy release. The recovery and liquefaction process optimizes energy consumption through a multi-stage design, while also improving system operating efficiency. 3) Auxiliary heat exchange:

[0073] a. Energy storage phase: Open the outlet valve of the first high-temperature liquid storage tank at the outlet of the first high-temperature liquid storage tank; utilize low-grade heat sources such as industrial waste heat and solar energy to heat the heat exchange working fluid in the first high-temperature liquid storage tank. The heat exchange working fluid in the first high-temperature liquid storage tank is transported to the heat exchange working fluid connecting pipe of the first warming heat exchanger, heating the gaseous carbon dioxide in the carbon dioxide connecting pipe. The heat exchange working fluid in the heat exchange working fluid connecting pipe of the first warming heat exchanger is cooled, and then transported to the first low-temperature liquid storage tank. The cooled heat exchange working fluid is transported to the heat exchange working fluid connecting pipe of the first cooling heat exchanger, cooling the gaseous carbon dioxide in the carbon dioxide connecting pipe. The heat exchange working fluid is heated and returned to the first high-temperature liquid storage tank.

[0074] b. energy release stage: open the second high-temperature liquid storage tank outlet valve at the outlet of the second high-temperature liquid storage tank; heat the heat transfer working medium in the second high-temperature liquid storage tank by using low-grade heat sources such as industrial waste heat and solar energy, and the heat transfer working medium in the second high-temperature liquid storage tank is transported to the heat transfer working medium connecting pipe of the second temperature-increasing heat exchanger to heat the gaseous carbon dioxide in the carbon dioxide connecting pipe, the temperature of the heat transfer working medium in the heat transfer working medium connecting pipe of the second temperature-increasing heat exchanger decreases and is transported to the second low-temperature liquid storage tank; the heat transfer working medium with reduced temperature is transported to the heat transfer working medium connecting pipe of the second temperature-decreasing heat exchanger to cool the gaseous carbon dioxide in the carbon dioxide connecting pipe, and the temperature of the heat transfer working medium increases and returns to the second high-temperature liquid storage tank.

[0075] Finally, it should be noted that the purpose of the disclosed embodiments is to help further understand the present application, but those skilled in the art can understand that various replacements and modifications are possible without departing from the spirit and scope of the present application and the appended claims. Therefore, the present application should not be limited to the disclosed embodiments, and the scope of the present application is defined by the scope of the claims.

Claims

1. A multi-phase state high efficiency solid state carbon dioxide energy storage system, characterized in that, The solid-state carbon dioxide energy storage system comprises a liquid storage tank, a first hydraulic pump, a second hydraulic pump, a throttling expansion valve, a solid-state storage tank, a first temperature-increasing heat exchanger, a second temperature-increasing heat exchanger, a compressor, a first temperature-decreasing heat exchanger, a second temperature-decreasing heat exchanger, a gaseous drive generator, a first high-temperature liquid storage tank, a second high-temperature liquid storage tank, a first low-temperature liquid storage tank and a second low-temperature liquid storage tank, wherein The energy storage stage outlet of the liquid storage tank is connected to the first hydraulic pump through a pipeline, the first hydraulic pump is connected to the energy storage stage inlet of the solid-state storage tank through a pipeline, and the throttling expansion valve is arranged at the energy storage stage inlet of the solid-state storage tank; the first switch valve is arranged at the energy storage stage outlet of the solid-state storage tank, the energy storage stage outlet of the solid-state storage tank is connected to the carbon dioxide inlet of the first temperature-increasing heat exchanger through a pipeline, and the carbon dioxide inlet and the carbon dioxide outlet of the first temperature-increasing heat exchanger are connected through a carbon dioxide connecting pipe; the carbon dioxide outlet of the first temperature-increasing heat exchanger is connected to the inlet of the compressor through a pipeline; the outlet of the compressor is connected to the carbon dioxide inlet of the first temperature-decreasing heat exchanger through a pipeline, the carbon dioxide inlet and the carbon dioxide outlet of the first temperature-decreasing heat exchanger are connected through a carbon dioxide connecting pipe, and the carbon dioxide outlet of the first temperature-decreasing heat exchanger is connected to the energy storage stage inlet of the liquid storage tank through a pipeline, so as to form an energy storage circulating pipeline, and the working medium in the energy storage circulating pipeline is carbon dioxide; The energy release stage outlet of the liquid storage tank is connected to the second hydraulic pump through a pipeline, the second hydraulic pump is connected to the energy release stage inlet of the solid-state storage tank through a pipeline, and the second switch valve is arranged at the energy release stage outlet of the solid-state storage tank; the energy release stage outlet of the solid-state storage tank is connected to the carbon dioxide inlet of the second temperature-increasing heat exchanger through a pipeline, the carbon dioxide inlet and the carbon dioxide outlet of the second temperature-increasing heat exchanger are connected through a carbon dioxide connecting pipe, the carbon dioxide outlet of the second temperature-increasing heat exchanger is connected to the gas inlet of the gaseous drive generator through a pipeline, the gas outlet of the gaseous drive generator is connected to the carbon dioxide inlet of the second temperature-decreasing heat exchanger through a pipeline, the carbon dioxide inlet and the carbon dioxide outlet of the second temperature-decreasing heat exchanger are connected through a carbon dioxide connecting pipe, and the carbon dioxide outlet of the second temperature-decreasing heat exchanger is connected to the energy release stage inlet of the liquid storage tank through a pipeline, so as to form an energy release circulating pipeline, and the working medium in the energy release circulating pipeline is carbon dioxide; A first high-temperature liquid storage tank outlet valve is arranged at the outlet of the first high-temperature liquid storage tank, the outlet of the first high-temperature liquid storage tank is connected to the heat exchange working medium inlet of the first temperature-increasing heat exchanger through a pipeline, and the heat exchange working medium inlet and the heat exchange working medium outlet of the first temperature-increasing heat exchanger are communicated through a heat exchange working medium connecting pipe; the heat exchange working medium outlet of the first temperature-increasing heat exchanger is connected to the inlet of the first low-temperature liquid storage tank through a pipeline; the outlet of the first low-temperature liquid storage tank is connected to the heat exchange working medium inlet of the first temperature-decreasing heat exchanger through a pipeline, and the heat exchange working medium inlet and the heat exchange working medium outlet of the first temperature-decreasing heat exchanger are communicated through a heat exchange working medium connecting pipe; the heat exchange working medium outlet of the first temperature-decreasing heat exchanger is connected to the inlet of the first high-temperature liquid storage tank through a pipeline, thereby forming a first auxiliary heat exchange circulation pipeline; the heat exchange working medium connecting pipe of the first temperature-increasing heat exchanger is not communicated with the carbon dioxide connecting pipe; the heat exchange working medium connecting pipe of the first temperature-decreasing heat exchanger is not communicated with the carbon dioxide connecting pipe; A second high-temperature liquid storage tank outlet valve is arranged at the outlet of the second high-temperature liquid storage tank, the outlet of the second high-temperature liquid storage tank is connected to the heat exchange working medium inlet of the second temperature-increasing heat exchanger through a pipeline, and the heat exchange working medium inlet and the heat exchange working medium outlet of the second temperature-increasing heat exchanger are communicated through a heat exchange working medium connecting pipe; the heat exchange working medium outlet of the second temperature-increasing heat exchanger is connected to the inlet of the second low-temperature liquid storage tank through a pipeline; the outlet of the second low-temperature liquid storage tank is connected to the heat exchange working medium inlet of the second temperature-decreasing heat exchanger through a pipeline, and the heat exchange working medium inlet and the heat exchange working medium outlet of the second temperature-decreasing heat exchanger are communicated through a heat exchange working medium connecting pipe; the heat exchange working medium outlet of the second temperature-decreasing heat exchanger is connected to the inlet of the second high-temperature liquid storage tank through a pipeline, thereby forming a second auxiliary heat exchange circulation pipeline; the heat exchange working medium connecting pipe of the second temperature-increasing heat exchanger is not communicated with the carbon dioxide connecting pipe; the heat exchange working medium connecting pipe of the second temperature-decreasing heat exchanger is not communicated with the carbon dioxide connecting pipe.

2. The solid state carbon dioxide energy storage system of claim 1, wherein, The first switch valve at the outlet of the energy storage stage of the solid-state storage tank adopts a gas valve; the second switch valve at the outlet of the energy release stage of the solid-state storage tank adopts a liquid valve.

3. The solid state carbon dioxide energy storage system of claim 1, wherein, The first and second temperature-increasing heat exchangers are heat exchangers that exchange heat between liquid and gas or liquid.

4. The solid state carbon dioxide energy storage system of claim 1, wherein, The working medium in the first and second auxiliary heat exchange circulation pipelines is a liquid working medium, which always remains in a liquid state without phase change in the temperature range.

5. The solid state carbon dioxide energy storage system of claim 1, wherein, The solid-state storage tank adopts a double-layer heat insulation layer, the inner layer is a low-temperature resistant material, and the outer layer is a vacuum insulation layer.

6. The solid state carbon dioxide energy storage system of claim 1, wherein, Further comprising a gas-liquid separation device, the gas-liquid separation device is arranged on the inner wall of the solid-state storage tank and located at the outlet of the energy storage stage, the solid-state carbon dioxide is left in the solid-state storage tank, and the gaseous carbon dioxide is discharged from the outlet of the energy storage stage through the gas-liquid separation device.

7. A method of controlling a multi-phase state high efficiency solid state carbon dioxide energy storage system as claimed in claim 1, characterized by, The control method comprises the following steps: 1) Energy storage stage: a. open the first hydraulic pump and close the second hydraulic pump; open the first switch valve and close the second switch valve; b. liquid carbon dioxide is stored in the liquid storage tank, and the liquid carbon dioxide output from the energy storage stage outlet of the liquid storage tank is sent to the throttling expansion valve through the first hydraulic pump to increase the pressure; c. Liquid carbon dioxide is rapidly depressurized and cooled in the throttling expansion valve, and is injected into the solid-state storage tank through the throttling expansion valve. Solid-state carbon dioxide and a small amount of gaseous carbon dioxide are formed in the solid-state storage tank, and phase change is realized in the solid-state storage tank; d. Solid-state carbon dioxide is directly collected and stored in the solid-state storage tank, and gaseous carbon dioxide enters the carbon dioxide connecting pipe of the first warming heat exchanger through the energy storage stage outlet, exchanges heat with the heat exchange medium in the heat exchange medium connecting pipe, the temperature rises, and is transported to the compressor; e. The gaseous carbon dioxide passing through the compressor has increased pressure and temperature, is transported to the carbon dioxide connecting pipe of the first cooling device, exchanges heat with the heat exchange medium in the heat exchange medium connecting pipe, and the temperature is reduced to liquefaction condition; f. Liquid carbon dioxide returns to the liquid storage tank; through the compression and cooling design, the compression energy consumption is effectively reduced, and the overall efficiency of the system is significantly improved; The energy storage stage stores solid-state carbon dioxide in the solid-state storage tank by converting liquid carbon dioxide into solid-state carbon dioxide; 2) Energy release and recovery stage: a. Open the second hydraulic pump and close the first hydraulic pump; open the second switch valve and close the first switch valve; b. Liquid carbon dioxide from the energy release stage outlet of the liquid storage tank is pressurized by the second hydraulic pump; high-pressure liquid carbon dioxide is injected into the energy release stage inlet of the solid-state storage tank, causing the solid-state carbon dioxide to warm up and partially change phase, further providing conditions for the generation of high-pressure carbon dioxide; solid, liquid and gaseous three-phase mixed carbon dioxide is ejected from the energy release stage outlet of the solid-state storage tank to the carbon dioxide connecting pipe of the second warming heat exchanger; c. The three-phase mixed carbon dioxide exchanges heat with the heat exchange medium in the heat exchange medium connecting pipe in the carbon dioxide connecting pipe of the second warming heat exchanger, is preheated or assisted heating, further improves its heat enthalpy value, the temperature rises, and is converted into high-pressure gaseous carbon dioxide, which provides sufficient energy for turbine power generation; d. High-pressure gaseous carbon dioxide is transported to the gaseous drive generator, and the gaseous carbon dioxide drives the turbine to rotate, converting the pressure energy and heat energy of the gas into mechanical energy, and outputting electric energy through the gaseous drive generator; e. The gaseous carbon dioxide passing through the gaseous drive generator is cooled by the second cooling heat exchanger to become liquid carbon dioxide and returns to the energy release stage inlet of the liquid storage tank, realizing cyclic utilization; The energy release process drives the gaseous drive generator to generate electricity by converting solid-state carbon dioxide into high-pressure gaseous carbon dioxide, Completes energy release; 3) Auxiliary heat exchange: a. Energy storage stage: open the first high-temperature liquid storage tank outlet valve; the heat exchange medium of the first high-temperature liquid storage tank is transported to the heat exchange medium connecting pipe of the first warming heat exchanger to heat the gaseous carbon dioxide in the carbon dioxide connecting pipe, the temperature of the heat exchange medium in the heat exchange medium connecting pipe of the first warming heat exchanger decreases, and is transported to the first low-temperature liquid storage tank; the temperature of the heat exchange medium is reduced and transported to the heat exchange medium connecting pipe of the first cooling heat exchanger to cool the gaseous carbon dioxide in the carbon dioxide connecting pipe, and the temperature of the heat exchange medium is increased and returned to the first high-temperature liquid storage tank; b. Energy release stage: open the second high-temperature liquid tank outlet valve; the heat transfer medium of the second high-temperature liquid tank is transported to the heat transfer medium connecting pipe of the second temperature-increasing heat exchanger to heat the gaseous carbon dioxide in the carbon dioxide connecting pipe, the temperature of the heat transfer medium in the heat transfer medium connecting pipe of the second temperature-increasing heat exchanger is reduced, and the heat transfer medium is transported to the second low-temperature liquid tank; the heat transfer medium with reduced temperature is transported to the heat transfer medium connecting pipe of the second temperature-decreasing heat exchanger to cool the gaseous carbon dioxide in the carbon dioxide connecting pipe, and the temperature of the heat transfer medium is increased to return to the second high-temperature liquid tank.

8. The control method according to claim 7, characterized by, In b. of step 2), the mixing ratio of liquid carbon dioxide to solid carbon dioxide is dynamically adjusted to be 1:1-10:1 by the second hydraulic pump.

9. The control method according to claim 7, characterized by, In d. of step 2), a heat exchange device is arranged at the inlet of the gaseous driving generator, and the heat exchange device heats the gaseous carbon dioxide by using low-grade heat sources such as industrial waste heat or solar energy.

10. The control method according to claim 7, characterized by, In step 3), the first and second high-temperature liquid tanks are heated by using low-grade heat sources such as industrial waste heat or solar energy.

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