Working fluid energy compensation device, carbon dioxide energy storage system and control method thereof

Abstract

The present invention discloses a working fluid energy compensation device, a carbon dioxide energy storage system and a control method thereof. The working fluid energy compensation device includes a gas compression mechanism and a state parameter acquisition unit, the input end of the gas compression mechanism is connected to the gas storage unit, the output end of the gas compression mechanism is connected to the input pipeline of the turbine, and the state parameter acquisition unit is connected to the input pipeline; the state parameter acquisition unit is configured to: detect and obtain the state parameters of the carbon dioxide gas in the input pipeline and calculate and determine the input working fluid energy value input to the inlet of the turbine; the gas compression mechanism is configured to: when the input working fluid energy value fails to reach the preset working fluid energy value, the carbon dioxide gas in the gas storage unit is compressed and input into the input pipeline to supplement the working fluid energy, so that the input working fluid energy value reaches the preset working fluid energy value. The scheme of the present invention can ensure that the operating efficiency of the turbine can reach the efficiency design value and improve the overall efficiency and stability of the operation of the carbon dioxide energy storage system.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide energy storage, and in particular to a working fluid energy compensation device, a carbon dioxide energy storage system and a control method thereof. Background Art

[0002] Using clean energy such as solar energy and wind energy to slow down the consumption of non-renewable traditional energy such as coal and oil has become an inevitable choice. Due to the intermittent, volatile, and peak-shifting characteristics of clean energy, energy storage technology has become one of the key technologies for the development of clean energy. At present, energy storage technology based on the gas-liquid phase change cycle of carbon dioxide uses excess electricity or clean energy to compress and condense gaseous carbon dioxide at room temperature and pressure in the gas storage tank into liquid carbon dioxide and store it in a storage tank during the off-peak period of electricity consumption, and stores the heat energy generated during the compression process. During the peak period of electricity consumption, the stored heat energy is used to heat the liquid carbon dioxide to gaseous state. The gaseous carbon dioxide drives the turbine to drive the generator to generate electricity, and the gaseous carbon dioxide after work returns to the gas storage for recycling. It has the advantages of simple structure, flexible layout, and high energy storage efficiency, and has gradually attracted widespread attention.

[0003] In the energy release component of the carbon dioxide energy storage system, the gas pipeline connecting the outlet of the energy release heat exchanger to the inlet of the turbine is relatively long. The temperature and pressure of the carbon dioxide gas heated by the energy release heat exchanger are reduced to varying degrees when it is transported to the inlet of the turbine, and the working fluid energy is lost. It often happens that the input working fluid energy input to the inlet of the turbine cannot reach the system set value, resulting in the turbine operating efficiency failing to reach the design value, affecting the stability of the system operation. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a working fluid energy compensation device, a carbon dioxide energy storage system and a control method thereof, so as to solve the problem of how to compensate the working fluid energy of the carbon dioxide gas input to the inlet of the turbine, thereby improving the stability of the operation of the carbon dioxide energy storage system.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The first aspect of the present invention is to provide a working fluid energy compensation device, which is applied to a carbon dioxide energy storage system. The carbon dioxide energy storage system includes a gas storage unit, an energy storage component, a liquid storage unit and an energy release component which are sequentially connected in a closed loop. The working fluid energy compensation device includes a gas compression mechanism and a state parameter acquisition unit. The energy release component includes a turbine. The input end of the gas compression mechanism is connected to the gas storage unit, and the output end of the gas compression mechanism is connected to the input pipeline of the turbine. The state parameter acquisition unit is connected to the input pipeline; wherein,

[0007] The state parameter acquisition unit is configured to: detect and obtain the state parameter of the carbon dioxide gas in the input pipeline, and calculate and determine the input working fluid energy value input to the inlet of the turbine based on the state parameter;

[0008] The gas compression mechanism is configured to: when the input working fluid energy value fails to reach the preset working fluid energy value, compress the carbon dioxide gas in the gas storage unit and input it into the input pipeline to supplement the working fluid energy, so that the input working fluid energy value reaches the preset working fluid energy value;

[0009] The preset working fluid energy value is the input working fluid energy value set by the system so that the operating efficiency of the turbine can reach the efficiency design value.

[0010] In a specific solution, the energy release assembly includes a first-stage turbine to an N-stage turbine connected in sequence, the output end of the air compression mechanism is interconnected with the input pipelines of the turbines at each stage, and the state parameter acquisition unit is interconnected with the input pipelines of the turbines at each stage;

[0011] The state parameter acquisition unit is configured to: detect and obtain the state parameters of the carbon dioxide gas in the input pipeline of each stage of the turbine, and calculate and determine the energy value of the input working fluid input to the inlet of each stage of the turbine based on the state parameters;

[0012] The gas compression mechanism is configured to: when the input working fluid energy value input to the inlet of the n-th stage turbine fails to reach the preset working fluid energy value of the n-th stage turbine, the carbon dioxide gas in the gas storage unit is compressed and input to the input pipeline corresponding to the n-th stage turbine to supplement the working fluid energy, so that the input working fluid energy value input to the inlet of the n-th stage turbine reaches the preset working fluid energy value of the n-th stage turbine;

[0013] Here, N is an integer greater than or equal to 2, n=1, 2, …, N.

[0014] In a specific solution, the output end of the air compression mechanism is connected to an output main pipeline, the output main pipeline is connected to N output branches, and the output main pipeline is connected to the input pipeline corresponding to the nth stage turbine through the nth output branch.

[0015] In a specific solution, each of the output branches is provided with a control valve and a check valve.

[0016] In a specific scheme, the working fluid energy compensation device also includes a control unit, the air compression mechanism and the state parameter acquisition unit are respectively connected to the control unit by electrical signals, the state parameter acquisition unit feeds back the detected state parameters to the control unit, and the control unit calculates and determines the input working fluid energy value input to the inlet of the turbine based on the state parameters and determines whether it reaches the preset working fluid energy value; when the input working fluid energy value fails to reach the preset working fluid energy value, the control unit controls the air compression mechanism to compress the carbon dioxide gas in the gas storage unit and input it into the input pipeline to supplement the working fluid energy.

[0017] In a specific embodiment, the state parameters include the pressure, temperature and flow rate of the carbon dioxide gas, and the gas compression mechanism controls the working fluid energy added to the input pipeline by adjusting the pressure and / or temperature and / or flow rate of the output compressed carbon dioxide gas.

[0018] In a specific solution, the driving power of the air compression mechanism comes from a photovoltaic power generation system or a wind power generation system.

[0019] The second aspect of the present invention is to provide a carbon dioxide energy storage system, comprising a gas storage unit, an energy storage assembly, a liquid storage unit and an energy release assembly connected in a closed loop in sequence, and the carbon dioxide energy storage system also includes the working fluid energy compensation device as described above.

[0020] A third aspect of the present invention is to provide a control method for the carbon dioxide energy storage system as described above, comprising:

[0021] The state parameter acquisition unit monitors and acquires the state parameters of the carbon dioxide gas in the input pipeline in real time, and calculates and determines the energy value of the input working fluid input to the inlet of the turbine based on the state parameters;

[0022] When the input working fluid energy value fails to reach the preset working fluid energy value, the gas compression mechanism is controlled to compress the carbon dioxide gas in the gas storage unit and input it into the input pipeline to supplement the working fluid energy, so that the input working fluid energy value reaches the preset working fluid energy value.

[0023] In a specific solution, the working fluid energy compensation device further includes a control unit, and the control method includes:

[0024] The state parameter acquisition unit monitors and obtains the state parameters of the carbon dioxide gas in the input pipeline in real time and feeds back the state parameters to the control unit;

[0025] The control unit calculates and determines the input working fluid energy value input to the inlet of the turbine based on the state parameter and determines whether it reaches the preset working fluid energy value;

[0026] When the input working fluid energy value fails to reach the preset working fluid energy value, the control unit calculates and determines the working fluid energy that needs to be supplemented and issues a control instruction to the air compression mechanism;

[0027] According to the control instruction, the gas compression mechanism compresses the carbon dioxide gas in the gas storage unit and inputs it into the input pipeline to supplement the working fluid energy, so that the input working fluid energy value reaches the preset working fluid energy value.

[0028] The working fluid energy compensation device, the carbon dioxide energy storage system and the control method thereof provided by the embodiments of the present invention, during the operation of the energy storage system, the state parameters of the carbon dioxide gas in the input pipeline are detected in real time by a state parameter acquisition unit, and the input working fluid energy value input to the inlet of the turbine is calculated and determined; when the input working fluid energy value fails to reach the preset working fluid energy value, the carbon dioxide gas in the gas storage unit is compressed by a gas compression mechanism and then input into the input pipeline to replenish the working fluid energy in time, so that the input working fluid energy value can reach the preset working fluid energy value, ensuring that the operating efficiency of the turbine can reach the efficiency design value, and improving the overall efficiency and stability of the operation of the carbon dioxide energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a specific connection structure diagram of the working fluid energy compensation device and the carbon dioxide energy storage system in an embodiment of the present invention;

[0030] Figure 2 4 is a flow chart of a method for controlling a carbon dioxide energy storage system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the present invention clearer, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Examples of these preferred embodiments are illustrated in the accompanying drawings. The embodiments of the present invention shown in the accompanying drawings and described according to the accompanying drawings are merely exemplary, and the present invention is not limited to these embodiments.

[0032] It should be noted that the same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the drawings, it is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limitations on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0033] It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the solutions according to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0034] See also Figure 1 The embodiment of the present invention first provides a working fluid energy compensation device 50 and a carbon dioxide energy storage system 100 including the working fluid energy compensation device 50 .

[0035] Specifically, the carbon dioxide energy storage system 100 mainly includes a gas storage unit 10, an energy storage component 20, a liquid storage unit 30 and an energy release component 40 which are connected in a closed loop in sequence. Among them, the gas storage unit 10 is used to store gaseous carbon dioxide at normal pressure, and the liquid storage unit 30 is used to store liquid carbon dioxide. The gaseous carbon dioxide flowing out of the gas storage unit 10 is converted into liquid carbon dioxide with a preset energy storage pressure through the energy storage component 20, and flows into the liquid storage unit 30, and energy storage is completed in this process. The liquid carbon dioxide output from the liquid storage unit 30 is converted into gaseous carbon dioxide at normal pressure by releasing energy through the energy release component 40, and flows into the gas storage unit 10, and energy release and application are completed in this process. Usually, the energy storage component 20 compresses and liquefies the gaseous carbon dioxide into liquid carbon dioxide during the off-peak period of electricity consumption or by utilizing wind and solar power abandonment, and stores it in the liquid storage unit 30, converting the energy into compression energy and heat energy storage; during the peak period of electricity consumption, the energy release component 40 gasifies and expands the liquid carbon dioxide to do work, and releases the stored energy and converts it into electrical energy for use.

[0036] Among them, the specific composition structures of the gas storage unit 10, the energy storage assembly 20, the liquid storage unit 30 and the energy release assembly 40 can be realized by referring to existing technologies, such as the technical solutions disclosed in existing patent documents CN116221616A, CN117628836A, and CN116857027A.

[0037] As a specific example, in this embodiment, Figure 1 As shown, the energy storage assembly 20 mainly includes a low-pressure compressor 21, an inter-stage heat exchanger 22, a high-pressure compressor 23, a post-stage heat exchanger 24 and a condenser 25 which are sequentially connected between the gas storage unit 10 and the liquid storage unit 30. In the compression heat release energy storage loop, the gaseous carbon dioxide is sequentially compressed by the low-pressure compressor 21 and the high-pressure compressor 23 in two stages, and then liquefied by the condenser 25 to form liquid carbon dioxide and stored in the liquid storage unit 30.

[0038] As a specific example, in this embodiment, Figure 1As shown, the energy release assembly 40 mainly includes an evaporator 41, a superheater 42, a high-pressure turbine 43, a reheater 44 and a low-pressure turbine 45 which are sequentially connected between the liquid storage unit 30 and the gas storage unit 10. In the heat absorption and expansion energy release circuit, the liquid carbon dioxide absorbs heat and vaporizes and expands in the evaporator 41, and then sequentially releases energy by performing work (such as power generation) to the outside through the high-pressure turbine 43 and the low-pressure turbine 45, and is converted into gaseous carbon dioxide at normal pressure and stored in the gas storage unit 10.

[0039] In the energy release component 40 of the carbon dioxide energy storage system 100, the energy release heat exchanger (eg Figure 1 The outlets of the superheater 42 and the reheater 44 in the turbine are connected to the turbine (e.g. Figure 1 The gas pipelines to the inlet of the high-pressure turbine 43 and the low-pressure turbine 45 in the energy release component 40 are relatively long. The temperature and pressure of the carbon dioxide gas heated by the energy release heat exchanger are reduced to varying degrees when it is transported to the inlet of the turbine, and the working fluid energy is lost. It often happens that the input working fluid energy value to the inlet of the turbine cannot reach the system setting value, resulting in the turbine operating efficiency failing to reach the design value, affecting the stability of the system operation. In particular, since the energy storage process and the energy release process are not carried out at the same time, the carbon dioxide energy storage system 100 is intermittently operated, and its operation process is mainly divided into three stages: energy storage stage, static stage and energy release stage. In the non-energy release stage, the relevant gas pipelines in the energy release component 40 are in a static state, and the temperature and pressure of the carbon dioxide gas in the gas pipeline are reduced to a greater extent, resulting in a greater loss of working fluid energy. Therefore, when starting and entering the energy release stage, the working fluid energy input from the gas pipeline to the turbine inlet cannot meet the turbine operating efficiency requirements, and the turbine start-up time is relatively long. This not only reduces the working efficiency of the carbon dioxide energy storage system, but also causes the carbon dioxide energy storage system to respond slowly to the upper-level control center (such as the upper-level power grid dispatching center).

[0040] In order to solve the above problems, the embodiment of the present invention provides a working fluid energy compensation device 50, which is mainly used in the carbon dioxide energy storage system 100, that is, Figure 1 The carbon dioxide energy storage system 100 provided in the above embodiment of the present invention further includes a working fluid energy compensation device 50 .

[0041] Specifically, Figure 1As shown, the working fluid energy compensation device 50 mainly includes a gas compression mechanism 51 and a state parameter acquisition unit 52. The input end of the gas compression mechanism 51 is connected to the gas storage unit 10, the output end of the gas compression mechanism 51 is connected to the input pipeline of the turbine, and the state parameter acquisition unit 52 is connected to the input pipeline. The state parameter acquisition unit 52 is configured to: detect and obtain the state parameters of the carbon dioxide gas in the input pipeline, and calculate and determine the input working fluid energy value input to the inlet of the turbine based on the state parameters. The gas compression mechanism 51 is configured to: when the input working fluid energy value fails to reach the preset working fluid energy value, the carbon dioxide gas in the gas storage unit 10 is compressed and input into the input pipeline to supplement the working fluid energy, so that the input working fluid energy value reaches the preset working fluid energy value. The preset working fluid energy value is the input working fluid energy value set by the system to enable the operating efficiency of the turbine to reach the efficiency design value.

[0042] Based on the working fluid energy compensation device 50 as described above, during the energy storage system operating in the energy release stage, the state parameters of the carbon dioxide gas in the input pipeline are detected and acquired in real time through the state parameter acquisition unit 52, and the input working fluid energy value input to the inlet of the turbine is calculated and determined; when the input working fluid energy value fails to reach the preset working fluid energy value, the carbon dioxide gas in the gas storage unit 10 is compressed by the gas compression mechanism 51 and input into the input pipeline to replenish the working fluid energy in time, so that the input working fluid energy value can reach the preset working fluid energy value, ensuring that the operating efficiency of the turbine can reach the efficiency design value, and improving the overall efficiency and stability of the operation of the carbon dioxide energy storage system. In particular, when the energy storage system starts from the non-energy release stage to the energy release stage, the carbon dioxide gas in the gas storage unit 10 can be compressed by the gas compression mechanism 51 and the working fluid energy including heat energy and pressure energy can be replenished in time, which greatly shortens the turbine startup time, thereby not only improving the working efficiency of the carbon dioxide energy storage system, but also improving the response speed of the carbon dioxide energy storage system to the upper control center (such as the upper power grid dispatching center).

[0043] As described above, in this embodiment, the energy release assembly 40 includes a superheater 42, a high-pressure turbine 43, a reheater 44, and a low-pressure turbine 45 connected in sequence. The high-pressure turbine 43 is connected to the superheater 42 via a first input pipeline 46, and the low-pressure turbine 45 is connected to the reheater 44 via a second input pipeline 47. Therefore, in this embodiment, Figure 1As shown, the output end of the gas compression mechanism 51 is interconnected with the first input pipeline 46 corresponding to the high-pressure turbine 43 and the second input pipeline 47 corresponding to the low-pressure turbine 45, and the state parameter acquisition unit 52 is also interconnected with the first input pipeline 46 and the second input pipeline 47. The state parameter acquisition unit 52 is configured to: detect and obtain the state parameters of the carbon dioxide gas in the first input pipeline 46 and the second input pipeline 47, and calculate and determine the input working fluid energy value input to the inlet of the high-pressure turbine 43 and the inlet of the low-pressure turbine 45 based on the state parameters. The gas compression mechanism 51 is configured as follows:

[0044] (1) When the energy value of the input working fluid input to the inlet of the high-pressure turbine 43 fails to reach the preset working fluid energy value of the high-pressure turbine 43, the carbon dioxide gas in the gas storage unit 10 is compressed and input to the first input pipeline 46 to supplement the working fluid energy, so that the energy value of the input working fluid input to the high-pressure turbine 43 reaches the preset working fluid energy value of the high-pressure turbine 43;

[0045] (2) When the energy value of the input working fluid input to the inlet of the low-pressure turbine 45 fails to reach the preset working fluid energy value of the low-pressure turbine 45, the carbon dioxide gas in the gas storage unit 10 is compressed and input to the second input pipeline 47 to supplement the working fluid energy, so that the energy value of the input working fluid input to the low-pressure turbine 45 reaches the preset working fluid energy value of the low-pressure turbine 45;

[0046] (3) When the energy values ​​of the working fluid input to the inlet of the high-pressure turbine 43 and the inlet of the low-pressure turbine 45 fail to reach the preset working fluid energy values ​​of the corresponding turbines, the carbon dioxide gas in the gas storage unit 10 is compressed and input to the input pipeline of the corresponding turbine to supplement the working fluid energy, so that the energy values ​​of the working fluid input to the high-pressure turbine 43 and the low-pressure turbine 45 can reach the preset working fluid energy values.

[0047] It should be noted that, in some other embodiments, the energy release component 40 may include a larger number of turbines connected in sequence. It can be understood as follows: the energy release component 40 includes a 1st stage turbine to an Nth stage turbine connected in sequence. At this time, the output end of the air compression mechanism 51 is interconnected with the input pipeline of each stage of the turbine, and the state parameter acquisition unit 52 is interconnected with the input pipeline of each stage of the turbine. Correspondingly, the state parameter acquisition unit 52 is configured to: detect and obtain the state parameters of the carbon dioxide gas in the input pipeline of each stage of the turbine, and calculate and determine the input working fluid energy value input to the inlet of each stage of the turbine based on the state parameters; the gas compression mechanism 51 is configured to: when the input working fluid energy value input to the inlet of the n-th stage turbine fails to reach the preset working fluid energy value of the n-th stage turbine, compress the carbon dioxide gas in the gas storage unit 10 and input it into the input pipeline corresponding to the n-th stage turbine to supplement the working fluid energy, so that the input working fluid energy value input to the n-th stage turbine reaches the preset working fluid energy value of the n-th stage turbine; wherein N is an integer greater than 2, n=1, 2, ..., N.

[0048] In this embodiment, the state parameters include the pressure, temperature and flow rate of the carbon dioxide gas, and the gas compression mechanism 51 controls the working fluid energy added to the input pipeline by adjusting the pressure and / or temperature and / or flow rate of the compressed carbon dioxide gas output. The state parameter acquisition unit 52 includes a parameter processing module and a pressure sensor, a temperature sensor and a flow meter (not shown in the drawings) connected to the input pipelines of each stage of the turbine. The pressure sensor, the temperature sensor and the flow meter detect and obtain the pressure, temperature and flow rate parameters of the carbon dioxide gas in the input pipelines of each stage in real time, and transmit them to the parameter processing module for data acquisition and processing.

[0049] The working fluid energy compensation device 50 in the above embodiment can respectively detect and obtain the input working fluid energy value of each of the turbine inlets in real time. When the input working fluid energy value of any turbine inlet fails to reach the preset working fluid energy value, the input pipeline of the turbine inlet can be targetedly supplemented with working fluid energy, thereby improving the accuracy of working fluid energy supplementation and further improving the efficiency of system operation.

[0050] In a specific solution, the output end of the air compression mechanism 51 is connected to an output main line 60, and the output main line 60 is connected to N output branches, and the output main line 60 is connected to the input pipeline corresponding to the n-th stage turbine through the n-th output branch. Furthermore, each of the output branches is respectively provided with a control valve 71 and a check valve 72. Figure 1As shown, in this embodiment, the output main line 60 is connected to the first input line 46 corresponding to the high-pressure turbine 43 through the first output branch 61, and the output main line 60 is connected to the second input line 47 corresponding to the low-pressure turbine 45 through the second output branch 62. The first output branch 61 and the second output branch 62 are respectively provided with a control valve 71 and a check valve 72. By controlling the control valve 71 on the corresponding output branch, the compressed carbon dioxide gas can be selectively added to the corresponding input line and its flow rate can be controlled.

[0051] Furthermore, in this embodiment, if Figure 1 As shown, the input end of the air compression mechanism 51 is connected to the air storage unit 10 via a connecting pipeline 63 , and a control valve 71 is also provided on the connecting pipeline 63 .

[0052] In this embodiment, Figure 1 As shown, the working fluid energy compensation device 50 also includes a control unit 53, and the air compression mechanism 51 and the state parameter acquisition unit 52 are respectively connected to the control unit 53 by electrical signals. The state parameter acquisition unit 52 feeds back the state parameters detected and acquired to the control unit 53, and the control unit 53 calculates and determines the input working fluid energy value input to the inlet of the turbine based on the state parameters and determines whether it reaches the preset working fluid energy value. When the input working fluid energy value fails to reach the preset working fluid energy value, the control unit 53 controls the air compression mechanism 51 to compress the carbon dioxide gas in the gas storage unit 10 and input it into the input pipeline to supplement the working fluid energy.

[0053] As a preferred solution, in this embodiment, the driving power of the air compression mechanism 51 mainly comes from a photovoltaic power generation system or a wind power generation system, and in particular, it can utilize wind and solar power abandonment. Of course, the power can also come from a power grid or other cheap power sources.

[0054] Based on the working fluid energy compensation device 50 and its corresponding carbon dioxide energy storage system 100 provided in the above embodiment, the embodiment of the present invention also provides a control method of the carbon dioxide energy storage system 100. Figure 2 , the control method comprises the steps of:

[0055] S101 , the state parameter acquisition unit 52 monitors and acquires the state parameters of the carbon dioxide gas in the input pipeline in real time, and calculates and determines the energy value of the input working fluid input to the inlet of the turbine based on the state parameters.

[0056] S102. When the input working fluid energy value fails to reach the preset working fluid energy value, the gas compression mechanism 51 is controlled to compress the carbon dioxide gas in the gas storage unit 10 and input it into the input pipeline to supplement the working fluid energy, so that the input working fluid energy value reaches the preset working fluid energy value.

[0057] As mentioned above, in this embodiment, as a preferred solution, the working fluid energy compensation device 50 further includes a control unit 53, and the control method specifically includes the following steps:

[0058] S201 , the state parameter acquisition unit 52 monitors and acquires the state parameters of the carbon dioxide gas in the input pipeline in real time and feeds back the state parameters to the control unit 53 .

[0059] S202: The control unit 53 calculates and determines the input working fluid energy value input to the inlet of the turbine based on the state parameter and determines whether the input working fluid energy value reaches the preset working fluid energy value.

[0060] S203 , when the input working fluid energy value fails to reach the preset working fluid energy value, the control unit 53 calculates and determines the working fluid energy that needs to be supplemented and issues a control instruction to the air compression mechanism 51 .

[0061] S204, the gas compression mechanism 51 compresses the carbon dioxide gas in the gas storage unit 10 according to the control instruction and inputs it into the input pipeline to supplement the working fluid energy, so that the input working fluid energy value reaches the preset working fluid energy value.

[0062] It should be noted that the preset working fluid energy value needs to be set according to the actual needs of the energy storage system. Different preset working fluid energy values ​​can be set in different operating stages. For example, corresponding to the startup stage and stable operation stage of the energy release component 40, the corresponding preset working fluid energy values ​​can be set for control.

[0063] In summary, the working fluid energy compensation device, the carbon dioxide energy storage system and the control method thereof provided by the above embodiments of the present invention, during the operation of the energy storage system, the state parameters of the carbon dioxide gas in the input pipeline are detected in real time by the state parameter acquisition unit, and the input working fluid energy value input to the inlet of the turbine is calculated and determined; when the input working fluid energy value fails to reach the preset working fluid energy value, the carbon dioxide gas in the gas storage unit is compressed by the gas compression mechanism and input into the input pipeline to replenish the working fluid energy in time, so that the input working fluid energy value can reach the preset working fluid energy value, ensuring that the operating efficiency of the turbine can reach the efficiency design value, and improving the overall efficiency and stability of the operation of the carbon dioxide energy storage system.

[0064] The above is only a specific implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A working fluid energy compensation device, applied to a carbon dioxide energy storage system, wherein the carbon dioxide energy storage system comprises a gas storage unit, an energy storage component, a liquid storage unit and an energy release component connected in a closed loop in sequence, characterized in that: The working fluid energy compensation device includes a gas compression mechanism and a state parameter acquisition unit, the energy release assembly includes a first-stage turbine to an N-stage turbine connected in sequence, the input end of the gas compression mechanism is connected to the gas storage unit, the output end of the gas compression mechanism is interconnected with the input pipelines of the turbines at each stage, and the state parameter acquisition unit is interconnected with the input pipelines of the turbines at each stage; The state parameter acquisition unit is configured to: detect and obtain the state parameters of the carbon dioxide gas in the input pipeline of each stage of the turbine, and calculate and determine the input working fluid energy value input to the inlet of each stage of the turbine based on the state parameters; The gas compression mechanism is configured to: when the energy value of the input working fluid input to the inlet of the n-th stage turbine fails to reach the preset working fluid energy value of the n-th stage turbine, the carbon dioxide gas in the gas storage unit is compressed and input to the input pipeline corresponding to the n-th stage turbine to supplement the working fluid energy, so that the energy value of the input working fluid input to the inlet of the n-th stage turbine reaches the preset working fluid energy value of the n-th stage turbine; The output end of the air compression mechanism is connected to an output main pipeline, the output main pipeline is connected to N output branches, the output main pipeline is connected to the input pipeline corresponding to the n-th stage turbine through the n-th output branch, and each of the output branches is respectively provided with a control valve and a check valve; Wherein, the state parameters include the pressure, temperature and flow rate of the carbon dioxide gas, and the gas compression mechanism controls the energy of the working fluid added to the input pipeline by adjusting the pressure and / or temperature and / or flow rate of the compressed carbon dioxide gas output; the preset working fluid energy value is the input working fluid energy value set by the system to enable the operating efficiency of the turbine to reach the efficiency design value; Here, N is an integer greater than or equal to 2, n=1, 2, …, N.

2. The working fluid energy compensation device according to claim 1, characterized in that: The working fluid energy compensation device also includes a control unit, the air compression mechanism and the state parameter acquisition unit are respectively connected to the control unit with electrical signals, the state parameter acquisition unit feeds back the detected state parameters to the control unit, and the control unit calculates and determines the input working fluid energy value input to the inlet of the turbine based on the state parameters and determines whether it reaches the preset working fluid energy value; when the input working fluid energy value fails to reach the preset working fluid energy value, the control unit controls the air compression mechanism to compress the carbon dioxide gas in the gas storage unit and input it into the input pipeline to supplement the working fluid energy.

3. The working fluid energy compensation device according to claim 1, characterized in that: The driving electric energy of the air compression mechanism comes from a photovoltaic power generation system or a wind power generation system.

4. A carbon dioxide energy storage system, comprising a gas storage unit, an energy storage component, a liquid storage unit and an energy release component connected in a closed loop, characterized in that: The carbon dioxide energy storage system also includes a working fluid energy compensation device as described in any one of claims 1-3.

5. A control method for a carbon dioxide energy storage system as claimed in claim 4, characterized in that: include: The state parameter acquisition unit monitors and acquires the state parameters of the carbon dioxide gas in the input pipeline in real time, and calculates and determines the energy value of the input working fluid input to the inlet of the turbine based on the state parameters; When the input working fluid energy value fails to reach the preset working fluid energy value, the gas compression mechanism is controlled to compress the carbon dioxide gas in the gas storage unit and input it into the input pipeline to supplement the working fluid energy, so that the input working fluid energy value reaches the preset working fluid energy value.

6. The control method according to claim 5, characterized in that: The working fluid energy compensation device further includes a control unit, and the control method includes: The state parameter acquisition unit monitors and obtains the state parameters of the carbon dioxide gas in the input pipeline in real time and feeds back the state parameters to the control unit; The control unit calculates and determines the input working fluid energy value input to the inlet of the turbine based on the state parameter and determines whether it reaches the preset working fluid energy value; When the input working fluid energy value fails to reach the preset working fluid energy value, the control unit calculates and determines the working fluid energy that needs to be supplemented and issues a control instruction to the air compression mechanism; According to the control instruction, the gas compression mechanism compresses the carbon dioxide gas in the gas storage unit and inputs it into the input pipeline to supplement the working fluid energy, so that the input working fluid energy value reaches the preset working fluid energy value.

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