Carbon dioxide energy storage system and lubricating oil supply device and control method thereof

Abstract

The present invention discloses a carbon dioxide energy storage system and its lubricating oil supply device and control method. The lubricating oil supply device comprises a first oil supply unit and a second oil supply unit respectively connected between the lubricating oil tank and the energy storage component and the energy release component. The first oil supply unit is configured to be able to provide a first amount of lubricating oil to the energy storage component and the energy release component, and the second oil supply unit is configured to be able to provide a second amount of lubricating oil to the energy storage component and the energy release component; wherein the second oil supply unit is connected to a liquid storage unit in the carbon dioxide energy storage system, and the high-pressure carbon dioxide gas in the liquid storage unit is used as a power source to drive the second oil supply unit to supply oil. The scheme of the present invention can make the drive control structure and drive control process of the second oil supply unit for providing accident lubricating oil simpler and faster in response, and effectively improve the reliability of accident lubricating oil supply.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide energy storage, and in particular to a carbon dioxide energy storage system and a lubricating oil supply device 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] The carbon dioxide energy storage system contains high-speed rotating mechanical equipment, mainly including compressors on the energy storage side and turbines on the energy release side. These high-speed rotating mechanical equipment need to be equipped with corresponding lubricating oil supply devices. At present, the lubricating oil supply device in the carbon dioxide energy storage system adopts a supply device similar to that in the generator set in the traditional thermal power generation system, which mainly includes 1 or 2 (one for use and one for backup) main working oil pumps driven by AC asynchronous motors + 1 emergency oil pump driven by a DC motor. When the unit is operating normally, the AC power provided by the plant power system drives the main working oil pump for oil supply; in emergency situations, such as power failure in the plant power system, the independent DC battery and the corresponding electronic control system quickly start the emergency oil pump to ensure the emergency shutdown of the unit. At present, the electronic control system of the emergency oil pump is relatively complex. For example, the technical solution disclosed in patent CN216767491U requires many nodes to be controlled, resulting in a high failure rate. In addition, the emergency oil pump relies on a power source set outside the energy storage system, and the response speed is slow. If the emergency oil pump cannot be started in an emergency, it will cause a safety accident and huge economic losses. Therefore, how to improve the reliability of emergency lubricating oil supply in the carbon dioxide energy storage system is a problem that needs to be solved. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a carbon dioxide energy storage system and a lubricating oil supply device and a control method thereof, so as to solve the problem of how to improve the reliability of accidental lubricating oil supply in the carbon dioxide energy storage system.

[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 lubricating oil supply device for a carbon dioxide energy storage system, the carbon dioxide energy storage system comprising an energy storage component, an energy release component and a liquid storage unit, the liquid storage unit being used to store liquid carbon dioxide and also containing high-pressure carbon dioxide gas, the lubricating oil supply device comprising a first oil supply unit and a second oil supply unit respectively connected between a lubricating oil tank and the energy storage component and the energy release component, the first oil supply unit being configured to be able to provide a first amount of lubricating oil to the energy storage component and the energy release component, and the second oil supply unit being configured to be able to provide a second amount of lubricating oil to the energy storage component and the energy release component;

[0007] The second oil supply unit is connected to the liquid storage unit, and the high-pressure carbon dioxide gas in the liquid storage unit is used as a power source to drive the second oil supply unit to supply oil.

[0008] In a specific embodiment, the second oil supply unit includes a second oil pump, a second pipeline and a second driving mechanism. The second oil pump is arranged in the lubricating oil tank. The second oil pump is connected to the energy storage component and the energy release component through the second pipeline. The second driving mechanism is a pneumatic rotary driving mechanism. The second driving mechanism is connected to the liquid storage unit. The second driving mechanism is configured to be driven to rotate by the high-pressure carbon dioxide gas in the liquid storage unit, thereby driving the second oil pump to supply oil.

[0009] In a specific embodiment, the second driving mechanism includes:

[0010] a vane type rotary cylinder, connected to the second oil pump, and used for rotationally driving the second oil pump;

[0011] A gas transmission pipeline, connected between the liquid storage unit and the blade type rotary cylinder, for transmitting the high-pressure carbon dioxide gas in the liquid storage unit to the blade type rotary cylinder to drive the blade type rotary cylinder to rotate;

[0012] The energized normally closed solenoid valve is connected to the gas transmission pipeline.

[0013] In a specific scheme, the carbon dioxide energy storage system also includes a shaft sealing gas storage container, which is used to store shaft sealing gas; the second driving mechanism also includes an exhaust pipeline, which is connected between the blade type rotary cylinder and the shaft sealing gas storage container, and is used to transport the carbon dioxide gas discharged from the blade type rotary cylinder to the shaft sealing gas storage container; a gas pressure regulating valve is provided on the gas transmission pipeline.

[0014] In a specific embodiment, the second oil amount is less than the first oil amount.

[0015] In a specific embodiment, the first oil amount is 2 to 3 times the second oil amount.

[0016] In a specific solution, the first oil supply unit includes a first oil pump, a first pipeline and a first driving mechanism, the first oil pump is arranged in the lubricating oil tank, the first oil pump is connected to the energy storage component and the energy release component through the first pipeline, and the first driving mechanism is used to drive the first oil pump;

[0017] The first pipeline includes a first oil supply main pipeline, a first oil supply branch pipeline and a second oil supply branch pipeline, wherein a first end of the first oil supply main pipeline is connected to an output end of the first oil pump, a first end of the first oil supply branch pipeline and a first end of the second oil supply branch pipeline are respectively connected to a second end of the first oil supply main pipeline, a second end of the first oil supply branch pipeline is connected to the energy storage component, and a second end of the second oil supply branch pipeline is connected to the energy release component, a first oil supply valve is provided on the first oil supply branch pipeline, and a second oil supply valve is provided on the second oil supply branch pipeline;

[0018] The second pipeline includes a second oil supply main line, a third oil supply branch line and a fourth oil supply branch line. The first end of the second oil supply main line is connected to the output end of the second oil pump. The first end of the third oil supply branch line and the first end of the fourth oil supply branch line are respectively connected to the second end of the second oil supply main line. The second end of the third oil supply branch line is connected to the energy storage component. The second end of the fourth oil supply branch line is connected to the energy release component. The third oil supply branch line is provided with a third oil supply valve, and the fourth oil supply branch line is provided with a fourth oil supply valve.

[0019] The second aspect of the present invention is to provide a carbon dioxide energy storage system, which includes 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 also includes the lubricating oil supply 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, the control method comprising:

[0021] When the carbon dioxide energy storage system operates normally, controlling the first oil supply unit to simultaneously supply lubricating oil to the energy storage component and the energy release component;

[0022] When the carbon dioxide energy storage system fails and the first oil supply unit is unable to supply oil, the second oil supply unit is started to supply lubricating oil to the energy storage component and the energy release component at the same time.

[0023] In a specific embodiment, the second oil amount is less than the first oil amount, and the control method includes:

[0024] When the carbon dioxide energy storage system operates normally, and the energy storage component is in an energy storage operating condition and the energy release component is in a cranking operating condition, controlling the first oil supply unit to supply lubricating oil to the energy storage component, and controlling the second oil supply unit to supply lubricating oil to the energy release component;

[0025] When the carbon dioxide energy storage system operates normally, and the energy release component is in an energy release operating condition and the energy storage component is in a cranking operating condition, controlling the first oil supply unit to supply lubricating oil to the energy release component, and controlling the second oil supply unit to supply lubricating oil to the energy storage component;

[0026] When the carbon dioxide energy storage system fails and the first oil supply unit is unable to supply oil, the second oil supply unit is controlled to supply lubricating oil to the energy storage component and the energy release component at the same time.

[0027] The carbon dioxide energy storage system and its lubricating oil supply device and control method provided by the embodiment of the present invention, the second oil supply unit for providing emergency lubricating oil in the lubricating oil supply device is driven by a power source unique to the carbon dioxide energy storage system, and the power source is specifically the high-pressure carbon dioxide gas in the liquid storage unit, thereby making the drive control structure and drive control process of the second oil supply unit simpler, faster and more reliable, effectively improving the reliability of emergency lubricating oil supply and improving the safety performance of the operation of the carbon dioxide energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a structural schematic diagram of a carbon dioxide energy storage system in an embodiment of the present invention;

[0029] Figure 2 Schematic diagram of the structure of the lubricating oil supply device in the embodiment of the present invention. DETAILED DESCRIPTION

[0030] 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.

[0031] 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.

[0032] 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.

[0033] See also Figure 1 and Figure 2 The embodiment of the present invention first provides a lubricating oil supply device 50 and a carbon dioxide energy storage system 100 including the lubricating oil supply device 50 .

[0034] Specifically, Figure 1 As shown, 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.

[0035] 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 the existing technology, such as the technical solutions disclosed in the existing documents CN116221616A, CN117628836A, and CN116857027A. The liquid storage unit 30 preferably uses a matrix self-balancing liquid storage unit as disclosed in the patent document CN222026765U.

[0036] As a specific example, in this embodiment, Figure 1 As shown, the energy storage assembly 20 mainly includes a compressor 21, an energy storage side heat exchanger 22 and a condenser 23 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 compressed by the compressor 21 and cooled by the energy storage side heat exchanger 22, and then liquefied by the condenser 23 to form liquid carbon dioxide and stored in the liquid storage unit 30.

[0037] As a specific example, in this embodiment, Figure 1 As shown, the energy release component 40 mainly includes an evaporator 41, an energy release side heat exchanger 42 and a turbine 43 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, is further heated and heated by the energy release side heat exchanger 42, and then releases energy by performing work (such as power generation) externally through the turbine 43, and is converted into gaseous carbon dioxide at normal pressure and stored in the gas storage unit 10.

[0038] Among them, the energy storage component 20 and the energy release component 40 both contain high-speed rotating mechanical equipment, mainly the compressor 21 in the energy storage component 20 and the turbine 43 in the energy release component 40. These high-speed rotating mechanical equipment need to be equipped with corresponding lubricating oil supply devices. In the existing related technologies, the lubricating oil supply device in the carbon dioxide energy storage system adopts a supply device similar to that in the generator set in the traditional thermal power generation system, which mainly includes 1 or 2 (one for use and one for backup) main working oil pumps driven by AC asynchronous motors + 1 emergency oil pump driven by DC motors. When the unit is operating normally, the AC power provided by the plant power system drives the main working oil pump for oil supply; in emergency situations, such as power failure in the plant power system, the emergency oil pump is quickly started by an independent DC battery and a corresponding electronic control system to ensure emergency shutdown of the unit. In the prior art, the electronic control system of the emergency oil pump is relatively complex, and there are many nodes that need to be controlled, resulting in a high failure rate. If the emergency oil pump cannot be started in an emergency, it will cause a safety accident and huge economic losses. Therefore, the safety performance of the lubricating oil supply device needs to be further improved. In the process of exploring solutions to this problem, the applicant of the present invention found that the reliability of the emergency oil pump can be improved by combining the unique power source of the carbon dioxide energy storage system 100 itself and changing the driving mode of the emergency oil pump. Specifically, in the current carbon dioxide energy storage system 100, the liquid storage container provided in the liquid storage unit 30 for storing liquid carbon dioxide has a large amount of high-pressure carbon dioxide gas in the pressure-maintaining pipeline at the top of the liquid storage container during the energy storage condition or the energy release condition. This part of the high-pressure carbon dioxide gas can be used as a power source to drive the emergency oil pump.

[0039] Based on the above concept, an embodiment of the present invention provides a lubricating oil supply device for a carbon dioxide energy storage system, specifically, as Figure 1 and Figure 2 As shown, the lubricating oil supply device 50 provided in this embodiment mainly includes a lubricating oil tank 53 and a first oil supply unit 51 and a second oil supply unit 52. The first oil supply unit 51 and the second oil supply unit 52 are respectively connected between the lubricating oil tank 53 and the energy storage component 20 and the energy release component 40. The first oil supply unit 51 is configured to be able to provide a first amount of lubricating oil to the energy storage component 20 and the energy release component 40. The second oil supply unit 52 is configured to be able to provide a second amount of lubricating oil to the energy storage component 20 and the energy release component 40. Among them, the second oil supply unit 52 is connected to the liquid storage unit 30, and uses the high-pressure carbon dioxide gas in the liquid storage unit 30 as a power source to drive the second oil supply unit 52 to supply oil.

[0040] As described above, the lubricating oil supply device 50, when the carbon dioxide energy storage system 100 operates normally, the first oil supply unit 51 supplies lubricating oil to the energy storage component 20 and the energy release component 40. When the carbon dioxide energy storage system 100 fails and the first oil supply unit 51 cannot supply oil, the second oil supply unit 52 is controlled to simultaneously supply lubricating oil to the energy storage component 20 and the energy release component 40, that is, the second oil supply unit 52 is mainly used to provide accident lubricating oil. In the lubricating oil supply device 50, the second oil supply unit 52 for providing accident lubricating oil is driven by a power source unique to the carbon dioxide energy storage system 100, and the power source is specifically the high-pressure carbon dioxide gas in the liquid storage unit 30, thereby making the drive control structure and drive control process of the second oil supply unit 52 simpler, faster and more reliable in response, effectively improving the reliability of the accident lubricating oil supply, and improving the safety performance of the operation of the carbon dioxide energy storage system. Compared with the traditional method of using DC batteries and corresponding electronic control systems to control the emergency oil supply unit, the solution of the present application does not require the installation of additional DC batteries as a power source outside the energy storage system, which can optimize the overall architecture of the energy storage system and reduce costs, and can also save electricity.

[0041] It should be noted that providing lubricating oil to the energy storage component 20 and the energy release component 40 as described above refers to providing lubricating oil to the rotating mechanical equipment in the energy storage component 20 and the energy release component 40, specifically the compressor 21 in the energy storage component 20 and the turbine 43 in the energy release component 40.

[0042] In this embodiment, Figure 2As shown, the first oil supply unit 51 mainly includes a first oil pump 51a, a first pipeline 51b and a first driving mechanism 51c. The first oil pump 51a is disposed in the lubricating oil tank 53, and the first oil pump 51a is connected to the energy storage component 20 and the energy release component 40, specifically to the compressor 21 and the turbine 43, through the first pipeline 51b. The first driving mechanism 51c is used to drive the first oil pump 51a to provide the first oil volume of lubricating oil.

[0043] Specifically, the first pipeline 51b includes a first oil supply main pipeline 511, a first oil supply branch pipeline 512, and a second oil supply branch pipeline 513. The first end of the first oil supply main pipeline 511 is connected to the output end of the first oil pump 51a, and the first end of the first oil supply branch pipeline 512 and the first end of the second oil supply branch pipeline 513 are respectively connected to the second end of the first oil supply main pipeline 511. The second end of the first oil supply branch pipeline 512 is connected to the energy storage component 20, specifically to the compressor 21. The second end of the second oil supply branch pipeline 513 is connected to the energy release component 40, specifically to the turbine 43.

[0044] Furthermore, the first oil supply branch 512 is provided with a first oil supply valve 514, and the second oil supply branch 513 is provided with a second oil supply valve 515. By controlling the opening and closing states of the first oil supply valve 514 and the second oil supply valve 515, the first oil supply unit 51 can selectively supply oil to the energy storage assembly 20 and / or the energy release assembly 40.

[0045] The first driving mechanism 51c is selected as a driving motor, specifically an AC driving motor.

[0046] In this embodiment, Figure 2 As shown, the second oil supply unit 52 mainly includes a second oil pump 52a, a second pipeline 52b and a second driving mechanism 52c. The second oil pump 52a is arranged in the lubricating oil tank 53, and the second oil pump 52a is connected to the energy storage component 20 and the energy release component 40 through the second pipeline 52b, specifically connected to the compressor 21 and the turbine 43. The second driving mechanism 52c is a pneumatic rotary driving mechanism, and the second driving mechanism 52c is connected to the liquid storage unit 30. The second driving mechanism 52c is configured to be driven to rotate by the high-pressure carbon dioxide gas in the liquid storage unit 30, thereby driving the second oil pump 52a to supply oil and provide the second oil quantity of lubricating oil.

[0047] Specifically, the second pipeline 52b includes a second main oil supply line 520, a third oil supply branch line 521 and a fourth oil supply branch line 522. The first end of the second main oil supply line 520 is connected to the output end of the second oil pump 52a, and the first end of the third oil supply branch line 521 and the first end of the fourth oil supply branch line 522 are respectively connected to the second end of the second main oil supply line 520. The second end of the third oil supply branch line 521 is connected to the energy storage component 20, specifically to the compressor 21. The second end of the fourth oil supply branch line 522 is connected to the energy release component 40, specifically to the turbine 43.

[0048] In this embodiment, Figure 2 As shown, the second driving mechanism 52c includes a vane-type rotary cylinder 523, an air supply pipeline 524 and an energized normally closed solenoid valve 525. The vane-type rotary cylinder 523 is connected to the second oil pump 52a, and is used to rotationally drive the second oil pump 52a. The air supply pipeline 524 is connected between the liquid storage unit 30 and the vane-type rotary cylinder 523, and is used to deliver the high-pressure carbon dioxide gas in the liquid storage unit 30 to the vane-type rotary cylinder 523, so as to drive the vane-type rotary cylinder 523 to rotate. The energized normally closed solenoid valve 525 is connected to the air supply pipeline 524, and is used to control the on and off of the air supply pipeline 524, and further control whether to start the second oil pump 52a. It should be noted that the energized normally closed solenoid valve 525 refers to a normally closed solenoid valve that is closed when powered on and opened when powered off.

[0049] The second drive mechanism 52c as described above only needs to control the energized normally closed solenoid valve 525 to be powered off and opened, so that the gas transmission pipeline 524 can be conducted, thereby inputting the high-pressure carbon dioxide gas in the liquid storage unit 30 into the blade-type rotary cylinder 523, driving the blade-type rotary cylinder 523 to rotate, and then driving the second oil pump 52a to provide the accident lubricating oil. The drive control structure and the drive control process are simpler, faster and more reliable, effectively improving the reliability of the second oil supply unit (accident oil supply unit) 52, and improving the safety performance of the operation of the carbon dioxide energy storage system. In particular, when the carbon dioxide energy storage system 100 loses power, the energized normally closed solenoid valve 525 automatically loses power and opens, thereby providing the accident lubricating oil in time, with a very high response speed.

[0050] Furthermore, a gas pressure regulating valve 526 is provided on the gas supply pipeline 524, and the pressure of the high-pressure carbon dioxide gas input to the blade-type rotary cylinder 523 is controlled by the gas pressure regulating valve 526, thereby adjusting the rotation speed of the blade-type rotary cylinder 523, thereby controlling the amount of oil provided by the second oil pump 52a.

[0051] Typically, see Figure 1 and Figure 2 The carbon dioxide energy storage system 100 further includes a shaft sealing gas storage container 60, which is used to store shaft sealing gas. The shaft sealing gas storage container 60 is mainly used to provide shaft sealing gas to the compressor 21 and the turbine 43. In this embodiment, Figure 2 As shown, the second driving mechanism 52c also includes an exhaust pipeline 527, which is connected between the blade-type rotary cylinder 523 and the shaft-sealed gas storage container 60, and is used to transport the carbon dioxide gas exhausted from the blade-type rotary cylinder 523 to the shaft-sealed gas storage container 60. Since the high-pressure carbon dioxide gas input from the liquid storage unit 30 to the blade-type rotary cylinder 523 is the circulating working fluid of the carbon dioxide energy storage system 100, this part of the high-pressure carbon dioxide gas drives the blade-type rotary cylinder 523 to rotate and is then recovered to the shaft-sealed gas storage container 60, and can subsequently be returned to the circulation pipeline of the energy storage system through the shaft-sealed gas pipeline, thereby avoiding the loss of the circulating working fluid.

[0052] The control method of the lubricating oil supply device 50 and the corresponding carbon dioxide energy storage system 100 as described above mainly includes:

[0053] (a1), when the carbon dioxide energy storage system 100 operates normally, the first oil supply unit 51 is controlled to simultaneously supply lubricating oil to the energy storage component 20 and the energy release component 40. By controlling the opening and closing states of the first oil supply valve 514 and the second oil supply valve 515, oil can be selectively supplied to the compressor 21 in the energy storage component 20 and / or the turbine 43 in the energy release component 40.

[0054] (b1) When the carbon dioxide energy storage system 100 fails and the first oil supply unit 51 fails to supply oil, the high-pressure carbon dioxide gas in the liquid storage unit 30 is controlled, and the second oil supply unit 52 is started to provide lubricating oil to the energy storage component 20 and the energy release component 40 at the same time.

[0055] As described above, when the carbon dioxide energy storage system 100 operates normally, the first oil supply unit 51 provides lubricating oil to the energy storage component 20 and the energy release component 40. However, during the operation of the carbon dioxide energy storage system 100, the energy storage process and the energy release process are usually not carried out at the same time. Its working principle requires the energy storage component 20 and the energy release component 40 to be started and stopped alternately and frequently (the so-called "cyclic load"), that is, whether it is the compressor 21 in the energy storage component 20 or the turbine 43 in the energy release component 40, it is necessary to alternately and frequently switch between the starting operation condition and the cranking operation condition. Therefore, the total time of the high-speed rotating mechanical equipment in the cranking operation condition is relatively long, and in the cranking operation condition, the equipment only needs a small amount of lubricating oil to meet the cranking requirements. Therefore, if in the cranking operation condition, the first oil supply unit 51 is also used to supply oil, and the power of the first oil pump 51a is relatively large, and the oil supply amount is much greater than the amount of lubricating oil required for the cranking, which not only increases the energy consumption of the system, but also increases the loss of lubricating oil.

[0056] It should be noted that the cranking operation condition refers to the following: because the rotating equipment often has a higher body temperature when it just enters the shutdown state from the high-speed operation state, in order to prevent the uneven temperature field distribution after the equipment is shut down and the thermal stress caused by the large temperature difference between the upper and lower cylinders, it is necessary to continuously turn the machine to eliminate the thermal stress caused by the temperature difference between the upper and lower cylinders until the equipment finally stops running completely.

[0057] In order to reduce system energy consumption and reduce lubricating oil loss, in this embodiment, as a preferred solution, the lubricating oil supply device 50 as described above is further improved, and the second oil supply unit 52 is also used to provide cranking lubricating oil, that is, the lubricating oil supply device 50 of this embodiment: when the compressor 21 in the energy storage component 20 and the turbine 43 in the energy release component 40 are in the starting operation condition, the first oil supply unit 51 provides the operating lubricating oil; when the compressor 21 in the energy storage component 20 and the turbine 43 in the energy release component 40 are in the cranking operation condition, the second oil supply unit 52 provides the cranking lubricating oil; when an accident occurs and an emergency shutdown is required, the second oil supply unit 52 provides the accident lubricating oil.

[0058] In order to achieve the above purpose, the lubricating oil supply device 50 of this embodiment first sets the second oil amount to be smaller than the first oil amount. That is, the second oil amount provided by the second oil supply unit 52 to the energy storage component 20 and the energy release component 40 is smaller than the first oil amount provided by the first oil supply unit 51 to the energy storage component 20 and the energy release component 40; secondly, in the second pipeline 52b of the second oil supply unit 52, as Figure 2As shown, the third oil supply branch 521 is provided with a third oil supply valve 528, and the fourth oil supply branch 522 is provided with a fourth oil supply valve 529. By controlling the opening and closing states of the third oil supply valve 528 and the fourth oil supply valve 529, the second oil supply unit 52 can selectively supply oil to the energy storage assembly 20 and / or the energy release assembly 40.

[0059] As described above, the lubricating oil supply device 50, the second oil supply unit 52 for providing emergency lubricating oil is also reused to provide turning gear lubricating oil, and shares the same oil supply pipeline. In some faults, such as the power outage of the factory power causing the carbon dioxide energy storage system 100 to lose power, the third oil supply branch 521 and the fourth oil supply branch 522 should be kept connected. Therefore, in this embodiment, the third oil supply valve 528 on the third oil supply branch 521 and the fourth oil supply valve 529 on the fourth oil supply branch 522 are selected as electromagnetic valves that are closed with power and opened when power is lost. When the energy storage system loses power and causes the third oil supply valve 528 and the fourth oil supply valve 529 to lose power, both are in the open state, and the third oil supply branch 521 and the fourth oil supply branch 522 are kept in a connected state.

[0060] As a preferred solution, in this embodiment, the first oil amount is 2 to 3 times the second oil amount.

[0061] Based on the above further improved lubricating oil supply device 50 and its corresponding carbon dioxide energy storage system 100, the control method thereof mainly includes:

[0062] (a2) When the carbon dioxide energy storage system 100 operates normally, and the energy storage component 20 is in the energy storage operating condition and the energy release component 40 is in the cranking operating condition, the first oil supply unit 51 is controlled to provide lubricating oil to the energy storage component 20, and the second oil supply unit 52 is controlled to provide lubricating oil to the energy release component 40.

[0063] Specifically, when the carbon dioxide energy storage system 100 operates normally, and the energy storage assembly 20 is in the energy storage operation state and the energy release assembly 40 is in the cranking operation state: in the first oil supply unit 51, the first driving mechanism 51c drives the first oil pump 51a to start, controls the first oil supply valve 514 to open and controls the second oil supply valve 515 to close, and the first oil quantity of lubricating oil provided by the first oil pump 51a is delivered to the compressor 21 in the energy storage assembly 20 via the first oil supply main line 511 and the first oil supply branch line 512. In the second oil supply unit 52, the second driving mechanism 52c drives the second oil pump 52a to start, controls the third oil supply valve 528 to close and controls the fourth oil supply valve 529 to open, and the second oil quantity of lubricating oil provided by the second oil pump 52a is delivered to the turbine 43 in the energy release assembly 40 via the second oil supply main line 520 and the fourth oil supply branch line 522.

[0064] (b2) When the carbon dioxide energy storage system 100 operates normally, and the energy release component 40 is in the energy release operating condition and the energy storage component 20 is in the cranking operating condition, the first oil supply unit 51 is controlled to provide lubricating oil to the energy release component 40, and the second oil supply unit 52 is controlled to provide lubricating oil to the energy storage component 20.

[0065] Specifically, when the carbon dioxide energy storage system 100 operates normally, and the energy release component 40 is in the energy release operation state and the energy storage component 20 is in the cranking operation state: in the first oil supply unit 51, the first driving mechanism 51c drives the first oil pump 51a to start, controls the first oil supply valve 514 to be closed and controls the second oil supply valve 515 to be opened, and the first oil quantity of lubricating oil provided by the first oil pump 51a is delivered to the turbine 43 in the energy release component 40 via the first oil supply main line 511 and the second oil supply branch line 513. In the second oil supply unit 52, the second driving mechanism 52c drives the second oil pump 52a to start, controls the third oil supply valve 528 to be opened and controls the fourth oil supply valve 529 to be closed, and the second oil quantity of lubricating oil provided by the second oil pump 52a is delivered to the compressor 21 in the energy storage component 20 via the second oil supply main line 520 and the third oil supply branch line 521.

[0066] (c) When the energy storage assembly 20 and the energy release assembly 40 are both in the cranking operation state, the second oil supply unit 52 is controlled to supply lubricating oil to the energy storage assembly 20 and the energy release assembly 40 respectively.

[0067] Specifically, when the carbon dioxide energy storage system 100 operates normally, and the energy storage component 20 and the energy release component 40 are both in the cranking operation state, the first oil supply unit 51 is closed, and in the second oil supply unit 52, the second drive mechanism 52c drives the second oil pump 52a to start, and the third oil supply valve 528 and the fourth oil supply valve 529 are controlled to be opened, and the second oil quantity of lubricating oil provided by the second oil pump 52a is simultaneously delivered to the compressor 21 in the energy storage component 20 and the turbine 43 in the energy release component 40.

[0068] (d) When the carbon dioxide energy storage system 100 fails and the first oil supply unit 51 fails to supply oil, the second oil supply unit 52 is controlled to supply lubricating oil to the energy storage assembly 20 and the energy release assembly 40 at the same time.

[0069] As described above, the lubricating oil supply device 50 controls the second oil supply unit 52 to provide a smaller amount of lubricating oil required for the equipment's cranking operation condition when the energy storage component 20 or the energy release component 40 is in the cranking operation condition, thereby not only reducing the energy consumption of the system, but also reducing the loss of lubricating oil.

[0070] In summary, the carbon dioxide energy storage system and its lubricating oil supply device and control method provided by the embodiment of the present invention, the second oil supply unit in the lubricating oil supply device for providing emergency lubricating oil is driven by a power source unique to the carbon dioxide energy storage system, and the power source is specifically the high-pressure carbon dioxide gas in the liquid storage unit, thereby making the drive control structure and drive control process of the second oil supply unit simpler, faster in response speed and more reliable, effectively improving the reliability of emergency lubricating oil supply and improving the safety performance of the carbon dioxide energy storage system. In a further preferred scheme, the second oil supply unit is also reused to provide cranking lubricating oil. When the energy storage component or the energy release component is in the cranking operating condition, the second oil supply unit provides a smaller amount of lubricating oil required to meet the equipment cranking operating condition, thereby not only reducing the energy consumption of the system, but also reducing the loss of lubricating oil and reducing costs.

[0071] 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 also comprises a lubricating oil supply device, wherein the liquid storage unit is used to store liquid carbon dioxide and also contains high-pressure carbon dioxide gas, characterized in that: The lubricating oil supply device comprises a first oil supply unit and a second oil supply unit respectively connected between the lubricating oil tank and the energy storage component and the energy release component, wherein the first oil supply unit is configured to be able to provide a first amount of lubricating oil to the energy storage component and the energy release component, and the second oil supply unit is configured to be able to provide a second amount of lubricating oil to the energy storage component and the energy release component; wherein the second oil supply unit is connected to the liquid storage unit, and uses the high-pressure carbon dioxide gas in the liquid storage unit as a power source to drive the second oil supply unit to supply oil; Wherein, the second oil amount is less than the first oil amount, and the control method includes: When the carbon dioxide energy storage system operates normally, and the energy storage component is in an energy storage operating condition and the energy release component is in a cranking operating condition, controlling the first oil supply unit to supply lubricating oil to the energy storage component, and controlling the second oil supply unit to supply lubricating oil to the energy release component; When the carbon dioxide energy storage system operates normally, and the energy release component is in an energy release operating condition and the energy storage component is in a cranking operating condition, controlling the first oil supply unit to supply lubricating oil to the energy release component, and controlling the second oil supply unit to supply lubricating oil to the energy storage component; When the carbon dioxide energy storage system fails and the first oil supply unit is unable to supply oil, the second oil supply unit is controlled to supply lubricating oil to the energy storage component and the energy release component at the same time.

2. The control method according to claim 1, characterized in that: The second oil supply unit includes a second oil pump, a second pipeline and a second driving mechanism. The second oil pump is arranged in the lubricating oil tank. The second oil pump is connected to the energy storage component and the energy release component through the second pipeline. The second driving mechanism is a pneumatic rotary driving mechanism. The second driving mechanism is connected to the liquid storage unit. The second driving mechanism is configured to be driven to rotate by the high-pressure carbon dioxide gas in the liquid storage unit, thereby driving the second oil pump to supply oil.

3. The control method according to claim 2, characterized in that: The second driving mechanism comprises: a vane type rotary cylinder, connected to the second oil pump, and used for rotationally driving the second oil pump; A gas transmission pipeline, connected between the liquid storage unit and the blade type rotary cylinder, for transmitting the high-pressure carbon dioxide gas in the liquid storage unit to the blade type rotary cylinder to drive the blade type rotary cylinder to rotate; The energized normally closed solenoid valve is connected to the gas transmission pipeline.

4. The control method according to claim 3, characterized in that: The carbon dioxide energy storage system also includes a shaft sealing gas storage container, which is used to store shaft sealing gas; the second driving mechanism also includes an exhaust pipeline, which is connected between the blade-type rotary cylinder and the shaft sealing gas storage container, and is used to transport the carbon dioxide gas discharged from the blade-type rotary cylinder to the shaft sealing gas storage container; a gas pressure regulating valve is provided on the gas transmission pipeline.

5. The control method according to claim 2, characterized in that: The first oil amount is 2 to 3 times the second oil amount.

6. The control method according to any one of claims 2 to 5, characterized in that: The first oil supply unit includes a first oil pump, a first pipeline and a first driving mechanism, the first oil pump is arranged in the lubricating oil tank, the first oil pump is connected to the energy storage component and the energy release component through the first pipeline, and the first driving mechanism is used to drive the first oil pump; The first pipeline includes a first oil supply main pipeline, a first oil supply branch pipeline and a second oil supply branch pipeline, wherein a first end of the first oil supply main pipeline is connected to an output end of the first oil pump, a first end of the first oil supply branch pipeline and a first end of the second oil supply branch pipeline are respectively connected to a second end of the first oil supply main pipeline, a second end of the first oil supply branch pipeline is connected to the energy storage component, and a second end of the second oil supply branch pipeline is connected to the energy release component, a first oil supply valve is provided on the first oil supply branch pipeline, and a second oil supply valve is provided on the second oil supply branch pipeline; The second pipeline includes a second oil supply main line, a third oil supply branch line and a fourth oil supply branch line. The first end of the second oil supply main line is connected to the output end of the second oil pump. The first end of the third oil supply branch line and the first end of the fourth oil supply branch line are respectively connected to the second end of the second oil supply main line. The second end of the third oil supply branch line is connected to the energy storage component. The second end of the fourth oil supply branch line is connected to the energy release component. The third oil supply branch line is provided with a third oil supply valve, and the fourth oil supply branch line is provided with a fourth oil supply valve.

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