Gas storage unit pressure relief device, carbon dioxide energy storage system and control method thereof

Abstract

The present invention discloses a gas storage unit pressure relief 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 gas storage unit pressure relief device includes a gas compression mechanism and a shaft sealing gas storage container. 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 shaft sealing gas storage container and / or the energy release component; wherein the gas compression mechanism is configured to: when overpressure occurs in the gas storage unit, the gas in the overpressure part of the gas storage unit is compressed and then input into the shaft sealing gas storage container and / or the energy release component. The present invention also discloses a carbon dioxide energy storage system and a control method thereof including the gas storage unit pressure relief device as described above. The scheme of the present invention can avoid the loss of energy storage medium due to pressure relief on the basis of being able to effectively relieve the pressure of the gas storage unit.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide energy storage, and in particular to a gas storage unit pressure relief 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 unit into liquid carbon dioxide and store it in the liquid storage unit 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 unit 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 carbon dioxide energy storage system, the gas storage unit is its core component, and the safety of the gas storage unit is particularly important. There are some safety hazards in the actual operation of the gas storage unit. For example, when the gas storage unit is over-pressurized, how to quickly release the pressure at this time becomes the key to whether the gas storage unit can operate safely. In the prior art, when the gas storage unit is over-pressurized, the carbon dioxide in the gas storage unit is usually discharged into the atmosphere through a pressure relief valve to reduce the volume of carbon dioxide in the gas storage unit, thereby achieving the purpose of pressure relief. However, the carbon dioxide in the gas storage unit is directly discharged into the atmosphere. Since carbon dioxide is the energy storage medium of the carbon dioxide energy storage system, directly discharging it into the atmosphere will cause the loss of energy storage medium, and then cause the loss of operating costs. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a gas storage unit pressure relief device, a carbon dioxide energy storage system and a control method thereof, so as to solve the problem of how to relieve pressure and avoid the loss of carbon dioxide energy storage medium when overpressure occurs in the gas storage unit.

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

[0006] A first aspect of the present invention is to provide a gas storage unit pressure relief device, which is applied to a carbon dioxide energy storage system, wherein 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, wherein the gas storage unit pressure relief device includes an air compression mechanism and a shaft sealing gas storage container, wherein the input end of the air compression mechanism is connected to the gas storage unit, and the output end of the air compression mechanism is connected to the shaft sealing gas storage container and / or the energy release component; wherein the air compression mechanism is configured to: when overpressure occurs in the gas storage unit, compress the gas in the overpressure part of the gas storage unit and input it into the shaft sealing gas storage container and / or the energy release component.

[0007] In a specific embodiment, the energy release assembly includes a high-pressure turbine and a low-pressure turbine connected in sequence;

[0008] The output end of the air compression mechanism is connected to the energy release assembly, including: the output end of the air compression mechanism is connected to the input end of the high-pressure turbine and / or the input end of the low-pressure turbine;

[0009] The gas compression mechanism compresses the gas in the overpressure portion and then inputs it into the energy release component, including: the gas compression mechanism compresses the gas in the overpressure portion and then inputs it into the input end of the high-pressure turbine and / or the input end of the low-pressure turbine.

[0010] In a specific embodiment, the output end of the air compression mechanism is connected to an output main line, and the output main line is connected to the shaft sealing gas storage container and / or the input end of the high-pressure turbine and / or the input end of the low-pressure turbine through corresponding output branches.

[0011] In a specific scheme, the output main line is connected to the input end of the shaft sealing gas storage container through a first output branch, and a first control valve and a first check valve are provided on the first output branch; the output main line is connected to the input end of the low-pressure turbine through a second output branch, and a second control valve and a second check valve are provided on the second output branch; the output main line is connected to the input end of the high-pressure turbine through a third output branch, and a third control valve and a third check valve are provided on the third output branch.

[0012] In a specific solution, the shaft sealing gas storage container is provided with a first output end, the first output end is connected to the output main line through a fourth output branch, and a fourth control valve is provided on the fourth output branch.

[0013] In a specific embodiment, the sealing gas storage container is provided with a second output end and a third output end, the second output end is connected to the energy storage component and the energy release component through a sealing gas supply pipeline, and the third output end is connected to an exhaust component.

[0014] 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.

[0015] 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 gas storage unit pressure relief device as described above.

[0016] A third aspect of the present invention is to provide a control method for the carbon dioxide energy storage system as described above, comprising:

[0017] Real-time monitoring and acquisition of air pressure status data in the air storage unit;

[0018] When overpressure occurs in the gas storage unit, the gas compression mechanism is controlled to compress the overpressure gas in the gas storage unit and then input it into the shaft sealing gas storage container and / or the energy release component.

[0019] In a specific solution, the output end of the gas compression mechanism is connected to the shaft sealing gas storage container and the energy release component, and the control method includes:

[0020] Real-time monitoring and acquisition of air pressure state data P1 in the air storage unit;

[0021] When P min <P1≤P th1 When the energy release component is in the startup operation stage, the gas compression mechanism is controlled to compress the gas in the overpressure part of the gas storage unit and then input it into the energy release component first;

[0022] When P min <P1≤P th1 When the energy release assembly is in a stable operation stage, the gas compression mechanism is controlled to compress the gas in the overpressure portion of the gas storage unit and then input it into the shaft sealing gas storage container in priority;

[0023] When P th1 <P1≤P th2 When the gas pressure mechanism is controlled to compress the gas in the overpressure portion of the gas in the gas storage unit and then input it into the shaft sealing gas storage container and the energy release component at the same time;

[0024] Among them, P min <P th1 <P th2 <P max , P min is the lower limit of the overpressure range allowed by the gas storage unit, P max is the upper limit of the overpressure range allowed by the gas storage unit, P th1 is the first overpressure threshold, Pth2 is the second overpressure threshold.

[0025] The gas storage unit pressure relief device, carbon dioxide energy storage system and control method thereof provided in the embodiments of the present invention, when the gas storage unit is over-pressured, the gas in the over-pressure part of the gas storage unit is compressed and then input into the shaft sealing gas storage container and / or the energy release component by controlling the gas compression mechanism, thereby effectively depressurizing the gas storage unit. Furthermore, the gas input into the shaft sealing gas storage container through the gas compression mechanism is used as the shaft sealing gas of the energy storage component and the energy release component, and can be returned to the circulation pipeline of the energy storage medium through the pipeline of the shaft sealing gas. The gas input into the energy release component through the gas compression mechanism is also returned to the circulation pipeline of the energy storage medium after releasing energy through the energy release component. Therefore, on the basis of being able to effectively depressurize the gas storage unit, the loss of the energy storage medium due to pressure relief can be avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a structural block diagram of a pressure relief device and a carbon dioxide energy storage system according to an embodiment of the present invention;

[0027] Figure 2 is a specific connection structure diagram of a pressure relief device and a carbon dioxide energy storage system according to an embodiment of the present invention;

[0028] Figure 3 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

[0029] 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.

[0030] 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.

[0031] 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.

[0032] See also Figure 1 and Figure 2 The embodiment of the present invention first provides a gas storage unit pressure relief device 50 and a carbon dioxide energy storage system 100 including the gas storage unit pressure relief device 50 .

[0033] 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.

[0034] 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.

[0035] As a specific example, in this embodiment, Figure 2 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.

[0036] As a specific example, in this embodiment, Figure 2As 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.

[0037] In the carbon dioxide energy storage system 100, the gas storage unit 10 is its core component, and its safety is particularly important. In this field, the gas storage unit 10 is usually a double-layer membrane structure and is built on the ground, including an inner membrane and an outer membrane. The outer membrane is used to resist wind and snow, and the inner membrane is used to store energy storage medium (gaseous carbon dioxide). An interlayer cavity is provided between the inner membrane and the outer membrane. The gas in the interlayer cavity props up the outer membrane to maintain its shape, so that the gas storage unit 10 is not easy to collapse. By flushing or extracting gas into the interlayer cavity, the air pressure inside and outside the interlayer cavity is maintained within a certain range, which satisfies the ability of the outer membrane to resist wind and snow. The span of the gas storage unit 10 is usually around 100 meters, and its floor area can be several thousand to tens of thousands of square meters, with a large volume. There may be some safety hazards in the actual operation of the gas storage unit 10. For example, if the gas storage unit 10 is over-pressurized, how to quickly release the pressure becomes the key to whether the gas storage unit 10 can operate safely. In addition, since the gas storage unit 10 stores energy storage fluid, how to avoid the loss of energy storage fluid during the pressure release process is also a problem that needs to be solved.

[0038] In order to solve the above problems, the embodiment of the present invention provides a gas storage unit pressure relief device 50, which is mainly used in the carbon dioxide energy storage system 100, that is, Figure 1 and Figure 2 The carbon dioxide energy storage system 100 provided in the above embodiment of the present invention further includes a gas storage unit pressure relief device 50 .

[0039] Specifically, Figure 1 and Figure 2 As shown, the gas storage unit pressure relief device 50 mainly includes a gas compression mechanism 51 and a shaft sealing gas storage container 52. The input end of the gas compression mechanism 51 is connected to the gas storage unit 10, and the output end of the gas compression mechanism 51 is connected to the shaft sealing gas storage container 52 and / or the energy release component 40. The gas compression mechanism 51 is configured to: when the gas storage unit 10 is over-pressured, the gas in the over-pressure part of the gas storage unit 10 is compressed and then input into the shaft sealing gas storage container 52 and / or the energy release component 40.

[0040] Based on the gas storage unit pressure relief device 50 as described above, when overpressure occurs in the gas storage unit 10, the gas in the overpressure part of the gas storage unit 10 is compressed by controlling the gas compression mechanism 51 and then input into the shaft sealing gas storage container 52 and / or the energy release component 40, thereby effectively relieving the pressure of the gas storage unit 10. Furthermore, the shaft sealing gas storage container 52 is connected to the energy storage component 20 and the energy release component 40, and the gas input into the shaft sealing gas storage container 52 through the air compression mechanism 51 serves as the shaft sealing gas of the energy storage component 20 and the energy release component 40, and can be returned to the circulation pipeline of the energy storage medium through the shaft sealing gas pipeline. The gas input into the energy release component 40 through the air compression mechanism 51 is also returned to the circulation pipeline of the energy storage medium after releasing energy through the energy release component 40. Therefore, the gas storage unit pressure relief device 50 and its corresponding carbon dioxide energy storage system 100 can avoid the loss of energy storage medium due to pressure relief on the basis of being able to effectively relieve the pressure of the gas storage unit 10.

[0041] It should be noted that the output end of the gas compression mechanism 51 can be connected only to the shaft sealing gas storage container 52, and the shaft sealing gas storage container 52 receives the depressurized gas and stores it for use as shaft sealing gas. The output end of the gas compression mechanism 51 can also be connected only to the energy release component 40, and the energy release component 40 receives the depressurized gas and returns it to the gas storage unit 10 through the circulation pipeline after releasing the energy. In this embodiment, Figure 1 and Figure 2 As shown, the output end of the air compression mechanism 51 is simultaneously connected to the shaft sealing gas storage container 52 and the energy release assembly 40. When overpressure occurs in the gas storage unit 10, it is possible to choose to release pressure to the shaft sealing gas storage container 52 or to the energy release assembly 40 or to release pressure to both the shaft sealing gas storage container 52 and the energy release assembly 40 according to the volume and pressure of the overpressure gas, which not only improves the pressure relief capacity of the system, but also improves the flexibility of system control.

[0042] As described above, in this embodiment, the energy release component 40 includes a high-pressure turbine 43 and a low-pressure turbine 45 connected in sequence, and the output end of the air compression mechanism 51 is connected to the energy release component 40 including the following schemes: (a) the output end of the air compression mechanism 51 is only connected to the input end of the high-pressure turbine 43, and the air compression mechanism 51 compresses the gas of the overpressure part and inputs it to the input end of the high-pressure turbine 43; (b) the output end of the air compression mechanism 51 is only connected to the input end of the low-pressure turbine 45, and the air compression mechanism 51 compresses the gas of the overpressure part and inputs it to the input end of the low-pressure turbine 45; (c) the output end of the air compression mechanism 51 is simultaneously connected to the input end of the high-pressure turbine 43 and the input end of the low-pressure turbine 45, and the air compression mechanism 51 compresses the gas of the overpressure part and inputs it to the input end of the high-pressure turbine 43 and the input end of the low-pressure turbine 45. In this embodiment, as Figure 2 As shown, the connection between the air compression mechanism 51 and the energy release assembly 40 adopts scheme (c), and the high-pressure turbine 43 and the low-pressure turbine 45 can both receive the depressurized gas and release energy, thereby further improving the system's depressurization capacity and enhancing the flexibility of system control.

[0043] In a specific solution, the output end of the air compressor 51 is connected to an output main line 53, and the output main line 53 is connected to the shaft seal gas storage container 52 and / or the input end of the high-pressure turbine 43 and / or the input end of the low-pressure turbine 45 through corresponding output branches. Figure 2 As shown, in this embodiment, the main output line 53 is connected to the input end of the shaft sealing gas storage container 52 through the first output branch 54, and the first output branch 54 is provided with a first control valve 61 and a first check valve 71; the main output line 53 is connected to the input end of the low-pressure turbine 45 through the second output branch 55, and the second output branch 55 is provided with a second control valve 62 and a second check valve 72; the main output line 53 is connected to the input end of the high-pressure turbine 43 through the third output branch 56, and the third output branch 56 is provided with a third control valve 63 and a third check valve 73. By controlling the first control valve 61, the second control valve 62 and the third control valve 63, the depressurized gas and its flow rate can be selectively input to the shaft sealing gas storage container 52 and / or the high-pressure turbine 43 and / or the low-pressure turbine 45.

[0044] Furthermore, in this embodiment, if Figure 2As shown, the shaft sealing gas storage container 52 is provided with a first output end, and the first output end is connected to the output main line 53 through a fourth output branch 57, and a fourth control valve 64 is provided on the fourth output branch 57. By providing the fourth output branch 57 and the fourth control valve 64, the depressurized gas stored in the shaft sealing gas storage container 52 can be input into the energy release component 40 and then returned to the gas storage unit 10.

[0045] Furthermore, in this embodiment, if Figure 2 As shown, the input end of the gas compression mechanism 51 is connected to the gas storage unit 10 through an input pipeline 80, and a fifth control valve 65 is provided on the input pipeline 80. When the gas storage unit 10 is over-pressured, the fifth control valve 65 is opened to input the over-pressure gas into the gas compression mechanism 51 for compression.

[0046] Furthermore, in this embodiment, if Figure 2 As shown, the shaft sealing gas storage container 52 is provided with a second output end and a third output end, the second output end is connected to the energy storage component 20 through a first shaft sealing gas supply pipeline 58a, the second output end is connected to the energy release component 40 through a second shaft sealing gas supply pipeline 58b, and the third output end is connected to an exhaust component 59.

[0047] Among them, the second output end is connected to the low-pressure compressor 21 and the high-pressure compressor 23 in the energy storage component 20 through the first shaft sealing gas supply pipeline 58a, and the second output end is connected to the high-pressure turbine 43 and the low-pressure turbine 45 in the energy release component 40 through the second shaft sealing gas supply pipeline 58b, thereby providing shaft sealing gas to the low-pressure compressor 21, the high-pressure compressor 23, the high-pressure turbine 43 and the low-pressure turbine 45, and the first shaft sealing gas supply pipeline 58a and the second shaft sealing gas supply pipeline 58b are respectively provided with a sixth control valve 66.

[0048] Wherein, the exhaust assembly 59 includes an exhaust tank 59a, the input end of the exhaust tank 59a is connected to the third output end through a connecting pipeline, the connecting pipeline is provided with a seventh control valve 67, and the output end of the exhaust tank 59a is connected to an eighth control valve 68. By providing the exhaust assembly 59, on the one hand, when the carbon dioxide energy storage medium in the energy storage system is mixed with air, the carbon dioxide working medium mixed with air can be stored in the shaft sealing gas storage container 52 and left to stand for a period of time. Since the density of carbon dioxide gas is greater than the density of air under this working condition, the air is placed in the upper part of the cavity of the shaft sealing gas storage container 52, and the air can be discharged into the atmosphere through the seventh control valve 67, the exhaust tank 59a, and the eighth control valve 68. On the other hand, in some extreme cases, when the pressure relief gas is input into the shaft sealing gas storage container 52 and the energy release assembly 40 at the same time and still cannot meet the pressure relief requirements, part of the gas in the shaft sealing gas storage container 52 can be discharged into the atmosphere through the exhaust assembly 59 to ensure the safety of the gas storage unit 10.

[0049] In this embodiment, the driving power of the air compressor 51 mainly comes from a photovoltaic power generation system or a wind power generation system, and in particular, can utilize wind and solar power abandonment. Of course, the power can also come from a power grid or other cheap power sources.

[0050] Based on the gas storage unit pressure relief device 50 and the 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 3 , the control method comprises the steps of:

[0051] S101, real-time monitoring to obtain air pressure status data in the air storage unit. Specifically, the data acquisition module provided in the air storage unit 10 can monitor and obtain corresponding air pressure status data.

[0052] S102: When the gas storage unit is over-pressurized, the gas compression mechanism is controlled to compress the gas in the over-pressure portion of the gas storage unit and input it into the shaft sealing gas storage container and / or the energy release component. Specifically, the control center of the energy storage system 100 determines whether the gas storage unit 10 is over-pressurized based on the gas pressure state data obtained in step S101. If the gas storage unit 10 is over-pressurized, a control instruction is issued to control the gas compression mechanism 51 to compress the gas in the over-pressure portion and input it into the shaft sealing gas storage container 52 and / or the energy release component 40.

[0053] As mentioned above, in this embodiment, as a preferred solution, the output end of the air compression mechanism 51 is simultaneously connected to the shaft sealing gas storage container 52 and the energy release component 40. At this time, in the control method:

[0054] In step S101 as described above, the control center of the energy storage system 100 monitors and acquires the air pressure state data P1 in the air storage unit 10 in real time.

[0055] In step S102 as described above, the control center of the energy storage system 100 performs the following processing according to the magnitude of the air pressure state data P1 and the operating stage of the system:

[0056] (1) When P min <P1≤P th1 When the energy release component 40 is in the startup operation stage, the gas compression mechanism 51 is controlled to compress the gas in the overpressure part of the gas storage unit 10 and then input it into the energy release component 40 first;

[0057] (2) When P min <P1≤P th1 When the energy release assembly 40 is in a stable operation stage, the gas compression mechanism 51 is controlled to compress the gas in the overpressure portion of the gas storage unit 10 and then input it into the shaft sealing gas storage container 52 in priority;

[0058] (3) When P th1 <P1≤P th2 When the gas is compressed, the gas compression mechanism 51 is controlled to compress the gas in the overpressure portion of the gas storage unit 10 and then input it into the shaft sealing gas storage container 52 and the energy release component 40 at the same time.

[0059] Among them, P min <P th1 <P th2 <P max , P min is the lower limit of the overpressure range allowed by the gas storage unit 10, P max is the upper limit of the overpressure range allowed by the gas storage unit 10, P th1 is the first overpressure threshold, P th2 is the second overpressure threshold. th1 and P th2 All are data pre-set in the control center, P th1 It can be understood as a relatively safe overpressure threshold. min ~P th1 Within the range, although overpressure occurs, it is relatively safe and controllable; P th2 It can be understood as the overpressure threshold of a serious alarm. When the gas pressure in the gas storage unit 10 exceeds P th2 , indicating that the gas storage unit 10 is seriously over-pressurized and the pressure should be released quickly to ensure the safe operation of the system.

[0060] In the above processing method (1), when P min <P1≤P th1, indicating that the gas storage unit 10 is over-pressurized, but relatively safe and controllable. At this time, if the energy release component 40 is in the startup operation stage, the high and low pressure turbines in the energy release component 40 require higher pressure energy and heat energy to start, and the gas compression mechanism 51 has higher pressure and heat after compressing the gas in the over-pressure part. Therefore, the gas compression mechanism 51 is controlled to compress the gas in the over-pressure part of the gas storage unit 10 and input it to the energy release component 40 first. On the basis of being able to relieve the pressure of the gas storage unit 10, the startup time of the energy release component 40 can be shortened, thereby improving system efficiency.

[0061] In the above processing method (2), when P min <P1≤P th1 , indicating that the gas storage unit 10 is over-pressurized, but relatively safe and controllable. At this time, if the energy release component 40 is in a stable operation stage, the gas compression mechanism 51 is controlled to compress the gas in the over-pressure part of the gas storage unit 10 and then input it into the shaft sealing gas storage container 52 first, so as to avoid disturbance to the energy release component 40 in stable operation.

[0062] It should be noted that when P min <P1≤P th1 When the energy release component 40 is in a stable operation stage, if it is monitored that the carbon dioxide gas output through the superheater 42 and the reheater 44 fails to meet the high / low pressure turbine inlet temperature and pressure parameter requirements, the gas compression mechanism 51 can also be controlled to compress the overpressure gas in the gas storage unit 10 and input it into the energy release component 40 (high / low pressure turbine) to supplement the pressure energy and thermal energy, thereby ensuring that the system efficiency of the carbon dioxide energy storage reaches the design value.

[0063] In the above processing method (3), when P th1 <P1≤P th2 , indicating that the gas storage unit 10 is overpressured and exceeds the relatively safe overpressure threshold P th1 At this time, the pressure needs to be quickly released to prevent the gas pressure of the gas storage unit 10 from reaching the overpressure threshold P of the serious alarm. th2 Therefore, the air compression mechanism 51 is controlled to compress the overpressure gas in the air storage unit 10 and input it into the shaft sealing gas storage container 52 and the energy release component 40 at the same time, so as to improve the pressure relief capacity for rapid pressure relief.

[0064] In summary, the gas storage unit pressure relief device, the carbon dioxide energy storage system and the control method thereof provided in the above embodiments of the present invention, when overpressure occurs in the gas storage unit, controls the gas compression mechanism to compress the overpressure gas in the gas storage unit and then input it into the shaft sealing gas storage container and / or the energy release component. In this way, on the basis of being able to effectively relieve the pressure of the gas storage unit, the loss of energy storage fluid due to pressure relief can be avoided.

[0065] 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 control method for 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, and further comprises a gas storage unit pressure relief device, characterized in that: The gas storage unit pressure relief device comprises a gas compression mechanism and a shaft sealing gas storage container, wherein 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 shaft sealing gas storage container and the energy release component; wherein the gas compression mechanism is configured to: when the gas storage unit is over-pressured, compress the gas in the over-pressure part of the gas storage unit and input it into the shaft sealing gas storage container and / or the energy release component; the control method comprises: Real-time monitoring and acquisition of air pressure state data P1 in the air storage unit; When P min <P1≤P th1 When the energy release component is in the startup operation stage, the gas compression mechanism is controlled to compress the gas in the overpressure part of the gas storage unit and then input it into the energy release component first; When P min <P1≤P th1 When the energy release assembly is in a stable operation stage, the gas compression mechanism is controlled to compress the gas in the overpressure portion of the gas storage unit and then input it into the shaft sealing gas storage container in priority; When P th1 <P1≤P th2 When the gas pressure mechanism is controlled to compress the gas in the overpressure portion of the gas in the gas storage unit and then input it into the shaft sealing gas storage container and the energy release component at the same time; Among them, P min <P th1 <P th2 <P max , P min is the lower limit of the overpressure range allowed by the gas storage unit, P max is the upper limit of the overpressure range allowed by the gas storage unit, P th1 is the first overpressure threshold, P th2 is the second overpressure threshold.

2. The control method of the carbon dioxide energy storage system according to claim 1, characterized in that: The energy release assembly includes a high-pressure turbine and a low-pressure turbine connected in sequence; The output end of the air compression mechanism is connected to the energy release assembly, including: the output end of the air compression mechanism is connected to the input end of the high-pressure turbine and / or the input end of the low-pressure turbine; The gas compression mechanism compresses the gas in the overpressure portion and then inputs it into the energy release component, including: the gas compression mechanism compresses the gas in the overpressure portion and then inputs it into the input end of the high-pressure turbine and / or the input end of the low-pressure turbine.

3. The control method of the carbon dioxide energy storage system according to claim 2, characterized in that: The output end of the air compression mechanism is connected to an output main line, and the output main line is respectively connected to the shaft sealing gas storage container, the input end of the high-pressure turbine and the input end of the low-pressure turbine through corresponding output branches.

4. The control method of the carbon dioxide energy storage system according to claim 3, characterized in that: The main output line is connected to the input end of the shaft sealing gas storage container through a first output branch, and a first control valve and a first check valve are arranged on the first output branch; the main output line is connected to the input end of the low-pressure turbine through a second output branch, and a second control valve and a second check valve are arranged on the second output branch; the main output line is connected to the input end of the high-pressure turbine through a third output branch, and a third control valve and a third check valve are arranged on the third output branch.

5. The control method of the carbon dioxide energy storage system according to claim 3, characterized in that: The shaft sealing gas storage container is provided with a first output end, the first output end is connected to the output main line through a fourth output branch, and a fourth control valve is provided on the fourth output branch.

6. The control method of the carbon dioxide energy storage system according to claim 5, characterized in that: The shaft sealing gas storage container is provided with a second output end and a third output end, the second output end is connected to the energy storage component and the energy release component through a shaft sealing gas supply pipeline, and the third output end is connected to an exhaust component.

7. The control method of the carbon dioxide energy storage system according to any one of claims 1 to 6, 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.

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