Breathing air zero-emission cold storage system for liquid air energy storage power station

Abstract

The present invention relates to the field of energy storage technology, and in particular to a cold storage system of a liquid air energy storage power station and a liquid air energy storage power station. The cold storage system of the liquid air energy storage power station includes a buffer device, a buffer storage tank, a medium-temperature cold storage working fluid storage tank and a low-temperature cold storage working fluid storage tank. The vent of the medium-temperature cold storage working fluid storage tank is connected to the vent of the low-temperature cold storage working fluid storage tank. The exhaust port of the medium-temperature cold storage working fluid storage tank, the buffer device and the air inlet of the buffer storage tank are connected in sequence to form a first gas passage. The exhaust port of the buffer storage tank, the buffer device and the air inlet of the medium-temperature cold storage working fluid storage tank are connected in sequence to form a second gas passage. Zero emission of breathing gas of the cold storage system is achieved, which can completely avoid the safety hazards caused by the emission of harmful gases, and avoid the effect of potential economic losses caused by the long-term use of a nitrogen generator to supplement high-purity nitrogen.

Description

Technical Field

[0001] The present invention relates to the field of energy storage technology, and in particular to a breathing gas zero-emission cold storage system of a liquid air energy storage power station and a liquid air energy storage power station. Background Art

[0002] As a large-scale energy storage technology, liquid air energy storage technology has the advantages of high energy storage density, no geographical restrictions, and high safety factor. It is a large-scale energy storage technology that is very suitable for promotion. As the key technical equipment of the liquid air energy storage system, the cold box is of great importance in terms of whether the cold storage medium can be properly utilized.

[0003] As the key technical key of the liquid air energy storage system, the operating performance of the cold storage system directly affects the overall performance of the system. During the operation of the atmospheric pressure cold storage unit tank, as the liquid phase enters and exits the tank, the pressure of the gas phase space at the top will also change. The design pressure of the atmospheric pressure storage tank is a slight positive pressure. When the pressure reaches the design upper limit, it is necessary to open the breathing valve to release the top gas. The top gas components are nitrogen and a small amount of cold storage medium evaporation gas. In order to recover the evaporated gas and avoid safety hazards caused by the leakage of dangerous gases, the BOG gas needs to be recycled and reused.

[0004] Limited by the conditions such as the selection of tank materials and manufacturing process, the design of normal pressure tanks generally allows a narrow range of pressure fluctuations, such as 20kPa.G ~ 25kPa.G. In this case, if the breathing gas generated during the operation of the tank is not discharged, it may cause overpressure or negative pressure, posing a hidden danger to the safety of the tank. Therefore, it is necessary to process the breathing gas of the cold storage system composed of nitrogen and a trace amount of evaporative gas of the cold storage working fluid.

[0005] Because the saturated vapor pressure of propane in a cryogenic state is extremely low, at -178°C it is only about 6*10 -3 Pa, accounts for a very low proportion in the breathing gas, so common liquid air energy storage equipment usually does not perform special treatment on BOG gas, or directly discharges it into the flare system. In this case, if the nitrogen in the exhaled gas is not recycled and reused, an additional long-term nitrogen generator unit will be required, and the lost deep-cold liquid propane will need to be regularly replenished over time. In the long run, the overall economic efficiency of the system is worrying; and the trace propane in the exhaled gas also poses certain risks in terms of environmental protection and safety. Summary of the invention

[0006] The present invention provides a zero-emission cold storage system for breathing gas of a liquid air energy storage power station and a liquid air energy storage power station, which are used to solve one of the defects in the prior art and achieve zero emission of breathing gas in the cold storage system, which can completely avoid the safety hazards caused by the emission of harmful gases and the potential economic losses caused by the long-term use of a nitrogen generator to supplement high-purity nitrogen.

[0007] The present invention provides a breathing air zero-emission cold storage system for a liquid air energy storage power station, comprising a buffer device, a buffer storage tank, a medium-temperature cold storage working fluid storage tank and a low-temperature cold storage working fluid storage tank, the air vent of the medium-temperature cold storage working fluid storage tank is connected with the air vent of the low-temperature cold storage working fluid storage tank, the exhaust port of the medium-temperature cold storage working fluid storage tank, the buffer device and the air inlet of the buffer storage tank are connected in sequence to form a first gas passage, the exhaust port of the buffer storage tank, the buffer device and the air inlet of the medium-temperature cold storage working fluid storage tank are connected in sequence to form a second gas passage.

[0008] According to a zero-emission cold storage system for breathing air of a liquid air energy storage power station provided by the present invention, the buffer device includes a first heat exchange component and a second heat exchange component, the exhaust port of the medium-temperature cold storage working fluid storage tank, the heat release passage of the first heat exchange component and the air inlet of the buffer storage tank are connected in sequence to form the first gas passage; the exhaust port of the buffer storage tank, the heat release passage of the second heat exchange component and the air inlet of the medium-temperature cold storage working fluid storage tank are connected in sequence to form the second gas passage.

[0009] According to a zero-emission cold storage system for breathing air of a liquid air energy storage power station provided by the present invention, the exhaust port of the medium-temperature cold storage working fluid storage tank, the heat absorption passage of the second heat exchange component, the heat release passage of the first heat exchange component and the air inlet of the buffer storage tank are connected in sequence to form the first gas passage.

[0010] According to a zero-emission cold storage system for breathing air of a liquid air energy storage power station provided by the present invention, the first heat exchange component includes a first heat exchanger and a gas compressor, and the heat release path of the gas compressor and the first heat exchanger are connected in sequence along the airflow direction in the first gas path.

[0011] According to a zero-emission cold storage system for breathing air of a liquid air energy storage power station provided by the present invention, the second heat exchange component includes a second heat exchanger, a low-temperature storage tank and a medium-temperature storage tank, the outlet of the low-temperature storage tank, the heat exchange path of the second heat exchanger and the inlet of the medium-temperature storage tank are connected in sequence, and the outlet of the medium-temperature storage tank, the heat exchange path of the second heat exchanger and the inlet of the low-temperature storage tank are connected in sequence.

[0012] According to a zero-emission cold storage system for breathing air of a liquid air energy storage power station provided by the present invention, a pipeline connecting the outlet of the medium-temperature cold storage working fluid storage tank and the gas compressor is provided with a first valve body, and a pipeline connecting the first heat exchanger and the buffer storage tank is provided with a second valve body.

[0013] According to a zero-emission cold storage system for breathing air of a liquid air energy storage power station provided by the present invention, a pipeline connecting the buffer storage tank and the second heat exchanger is provided with a third valve body, and a pipeline connecting the second heat exchanger and the inlet of the medium-temperature cold storage working fluid storage tank is provided with a fourth valve body.

[0014] According to a zero-emission cold storage system for breathing air of a liquid air energy storage power station provided by the present invention, the pipeline connecting the outlet of the low-temperature storage tank and the second heat exchanger is provided with a fifth valve body, the pipeline connecting the second heat exchanger and the inlet of the medium-temperature storage tank is provided with a sixth valve body, the pipeline connecting the outlet of the medium-temperature storage tank and the second heat exchanger is provided with a seventh valve body, and the pipeline connecting the second heat exchanger and the inlet of the low-temperature storage tank is provided with an eighth valve body.

[0015] According to a breathing gas zero-emission cold storage system of a liquid air energy storage power station provided by the present invention, a ninth valve body is provided in a pipeline connecting the vent of the medium-temperature cold storage working fluid tank and the vent of the low-temperature cold storage working fluid tank.

[0016] The present invention also provides a liquid air energy storage power station, including the breathing air zero-emission cold storage system of the liquid air energy storage power station as described above.

[0017] The zero-emission cold storage system for breathing gas of the liquid air energy storage power station of the embodiment of the present invention provides a cold storage system for recovering breathing gas mainly composed of nitrogen and evaporated gas of cold storage working fluid generated during the operation of the large storage tank of the liquid phase cold storage system, that is, the first gas passage and the second gas passage are both circulation passages for the breathing gas.

[0018] When the top gas phase space of the low-temperature cold storage working medium storage tank and the medium-temperature cold storage working medium storage tank reaches the maximum design pressure during the energy release process, the slightly positive pressure breathing gas in the medium-temperature cold storage working medium storage tank and the low-temperature cold storage working medium storage tank is pressurized and cooled by the buffer device on the first gas passage, and then stored in the buffer storage tank as a normal temperature high-pressure cold storage working medium. When the pressure of the top gas phase space of the low-temperature cold storage working medium storage tank and the medium-temperature cold storage working medium storage tank no longer increases, the first gas passage is closed.

[0019] When the top gas phase space of the low-temperature cold storage tank and the medium-temperature cold storage tank reaches the minimum design pressure during the energy storage process, the normal temperature high-pressure breathing gas stored in the buffer tank is cooled and depressurized by the buffer device on the second gas passage, and then enters the medium-temperature cold storage tank and the low-temperature cold storage tank as breathing gas in a slightly positive pressure state to maintain the gas phase space pressure of the two tanks not less than the set minimum value. When the pressure of the top gas phase space of the low-temperature cold storage tank and the medium-temperature cold storage tank no longer decreases, the second gas passage is closed.

[0020] In this embodiment, when the design pressure fluctuation range of the atmospheric pressure storage tank is relatively narrow, a buffer device and a buffer storage tank storage and recovery design are used to avoid the overpressure and negative pressure of the storage tank caused by the method of relying solely on the connection of the top gas phase space. At the same time, zero emission of breathing gas in the cold storage system can be achieved, and the safety hazards caused by harmful gas emissions can be completely avoided, as well as the potential economic losses caused by the long-term use of nitrogen generators to supplement high-purity nitrogen, thereby realizing a liquid cold storage system that is efficient, environmentally friendly, safe, and economical.

[0021] Moreover, the low-temperature cold storage working fluid storage tank and the medium-temperature cold storage working fluid storage tank are initially pressure-stabilized in the form of top connection. Affected by the liquid cold storage working fluid entering and exiting the tank, the top gas flows through the vent connecting pipeline of the two tanks, so as to minimize the pressure change of the gas phase space at the top of the tank during operation, greatly reduce the breathing gas volume, and also minimize the scale and cost of the breathing gas recovery device composed of the subsequent buffer device and the buffer storage tank.

[0022] In addition to the technical problems solved by the present invention, the technical features of the technical solutions constituted, and the advantages brought about by the technical features of these technical solutions described above, other technical features of the present invention and the advantages brought about by these technical features will be further explained in conjunction with the accompanying drawings or will be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 This is one of the structural schematic diagrams of the breathing gas zero-emission cold storage system of the liquid air energy storage power station provided by the present invention;

[0025] Figure 2 This is the second structural schematic diagram of the breathing air zero-emission cold storage system of the liquid air energy storage power station provided by the present invention.

[0026] Reference numerals:

[0027] 100, buffer device; 110, first heat exchange component; 111, first heat exchanger; 112, gas compressor; 120, second heat exchange component; 121, second heat exchanger; 122, low-temperature storage tank; 123, medium-temperature storage tank; 124, medium-temperature heat exchange medium pump; 125, low-temperature heat exchange medium pump;

[0028] 200, buffer storage tank; 300, medium temperature cold storage tank; 400, low temperature cold storage tank;

[0029] 510, a first valve body; 520, a second valve body; 530, a third valve body; 540, a fourth valve body; 550, a fifth valve body; 560, a sixth valve body; 570, a seventh valve body; 580, an eighth valve body; 590, a ninth valve body. DETAILED DESCRIPTION

[0030] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0031] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0032] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0033] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0034] In addition, in the description of the embodiments of the present invention, unless otherwise specified, "multiple", "multiple roots", and "multiple groups" mean two or more, and "several", "several roots", and "several groups" mean one or more.

[0035] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0036] The liquid air energy storage power station provided in the embodiment of the present invention includes a circulating water system, a cold storage system, an energy storage device and an energy release device. The energy storage device inputs normal temperature and high pressure air to the cold storage system, and the cold storage system inputs normal temperature and high pressure air to the energy release device.

[0037] In the energy storage stage, normal temperature and normal pressure air is compressed to high pressure by the multi-stage air compressor of the energy storage device, and cooled to normal temperature by the multi-stage cooler of the energy storage device. The electricity used in this process is driven by renewable energy or grid off-peak electricity, and the compression heat of the energy storage device is stored in a high-temperature circulating water heat storage spherical tank through the circulating water system. The normal temperature and high pressure liquid air output by the energy storage device enters the cold storage system, exchanges heat with the cold storage medium in the cooling device of the cold storage system, cools to low temperature, and enters the liquid air storage tank in the form of gas and liquid after decompression and expansion, that is, low temperature and normal pressure liquid air is stored in the liquid air storage tank. The low temperature gaseous air flows back to the cold storage system to provide cooling capacity, completing the energy storage process of the liquid air energy storage power station.

[0038] During the energy release stage, low-temperature, normal-pressure liquid air enters the cold storage system through a liquid air pump, exchanges heat with the cold storage medium in the heating device of the cold storage system, absorbs heat to increase temperature and pressurization, returns to normal temperature and high pressure, and enters the multi-stage air turbine of the energy release device. The circulating water system releases the stored compression heat to the normal-temperature, high-pressure air. The turbine rotates and does work, driving the generator to generate electricity and transmit it to the power grid, completing the energy release process of the liquid air energy storage power station.

[0039] In order to ensure that the low-temperature cold storage working fluid storage tank 400 and the medium-temperature cold storage working fluid storage tank 300 are as stable as possible during operation, the top gas phase spaces of the two tanks are connected through pipelines. During the energy storage process, the liquid cold storage working fluid in the low-temperature cold storage working fluid storage tank 400 flows out, and enters the medium-temperature cold storage working fluid storage tank 300 after releasing the cold through the cooling device of the cold storage system. At this time, the top gas of the medium-temperature cold storage working fluid storage tank 300 enters the low-temperature cold storage working fluid storage tank 400 through the vent, so that the tank top pressure of the two tanks is stabilized within a certain range. At the end of the energy storage stage, the amount of gas in the low-temperature cold storage working fluid storage tank 400 is large, and the volume is reduced by cooling, and the pressure of the top gas phase space of the two tanks reaches the minimum value. During the energy release process, the liquid cold storage medium in the medium-temperature cold storage medium storage tank 300 flows out, absorbs cold energy through the cooling device of the cold storage system, and then enters the low-temperature cold storage medium storage tank 400. At this time, the top gas of the low-temperature cold storage medium storage tank 400 enters the medium-temperature cold storage medium storage tank 300 through the vent, so that the tank top pressure of the two tanks is stabilized within a certain range. At the end of the energy release stage, the amount of gas in the medium-temperature cold storage medium storage tank 300 is large, and the volume expands due to heat, and the pressure of the gas phase space at the top of the two tanks reaches the maximum value.

[0040] The above process can make low-temperature heat storage tanks and medium-temperature heat storage tanks achieve pressure stabilization and zero emission of breathing gas within a certain range. However, due to the conditions such as the manufacturing process of atmospheric pressure tanks, the allowable pressure fluctuation range of the tank is generally narrow, such as 20kPa.G~25kPa.G. At this time, the structure that only relies on the top gas phase space connection will cause overpressure and negative pressure in the tank.

[0041] like Figure 1 and Figure 2 As shown, the breathing gas zero-emission cold storage system of the liquid air energy storage power station provided by the embodiment of the present invention includes a buffer device 100, a buffer storage tank 200, a medium-temperature cold storage working fluid storage tank 300 and a low-temperature cold storage working fluid storage tank 400, the air vent of the medium-temperature cold storage working fluid storage tank 300 is connected to the air vent of the low-temperature cold storage working fluid storage tank 400, the exhaust port of the medium-temperature cold storage working fluid storage tank 300, the buffer device 100 and the air inlet of the buffer storage tank 200 are connected in sequence to form a first gas passage, and the exhaust port of the buffer storage tank 200, the buffer device 100 and the air inlet of the medium-temperature cold storage working fluid storage tank 300 are connected in sequence to form a second gas passage.

[0042] The zero-emission cold storage system for breathing gas of the liquid air energy storage power station of the embodiment of the present invention provides a cold storage system for recovering breathing gas mainly composed of nitrogen and evaporated gas of cold storage working fluid generated during the operation of the large storage tank of the liquid phase cold storage system, that is, the first gas passage and the second gas passage are both circulation passages for the breathing gas.

[0043] When the top gas phase space of the low-temperature cold storage working medium storage tank 400 and the medium-temperature cold storage working medium storage tank 300 reaches the maximum design pressure during the energy release process, the slightly positive pressure breathing gas in the medium-temperature cold storage working medium storage tank 300 and the low-temperature cold storage working medium storage tank 400 is pressurized and cooled by the buffer device 100 on the first gas passage, and then stored in the buffer storage tank 200 in the state of normal temperature high pressure cold storage working medium. When the pressure of the top gas phase space of the low-temperature cold storage working medium storage tank 400 and the medium-temperature cold storage working medium storage tank 300 no longer increases, the first gas passage is closed.

[0044] When the top gas phase space of the low-temperature cold storage working medium storage tank 400 and the medium-temperature cold storage working medium storage tank 300 reaches the minimum design pressure during the energy storage process, the normal temperature high-pressure breathing gas stored in the buffer storage tank 200 is cooled and depressurized by the buffer device 100 on the second gas passage, and then enters the medium-temperature cold storage working medium storage tank 300 and the low-temperature cold storage working medium storage tank 400 as breathing gas in a slightly positive pressure state to maintain the gas phase space pressure of the two not less than the set minimum value. When the top gas phase space pressure of the low-temperature cold storage working medium storage tank 400 and the medium-temperature cold storage working medium storage tank 300 no longer decreases, the second gas passage is closed.

[0045] In this embodiment, when the design pressure fluctuation range of the atmospheric pressure storage tank is relatively narrow, the buffer device 100 and the buffer storage tank 200 are used for storage and recovery design, thereby avoiding the overpressure and negative pressure of the storage tank caused by the method of relying solely on the connection of the top gas phase space. At the same time, the cold storage system can achieve zero emission of breathing gas, completely avoid the safety hazards caused by harmful gas emissions, and avoid the potential economic losses caused by the long-term use of nitrogen generators to supplement high-purity nitrogen, thereby realizing a liquid cold storage system that is efficient, environmentally friendly, safe, and economical.

[0046] Moreover, the low-temperature cold storage working fluid storage tank 400 and the medium-temperature cold storage working fluid storage tank 300 are initially pressure-stabilized in the form of top connection. Affected by the liquid cold storage working fluid entering and exiting the tanks, the top gas flows through the vent connecting pipeline of the two tanks, so as to reduce the pressure change of the gas phase space at the top of the tank during operation as much as possible, greatly reduce the breathing gas volume, and also reduce the scale and cost of the breathing gas recovery device composed of the subsequent buffer device 100 and the buffer storage tank 200 as much as possible.

[0047] In this embodiment, the buffer storage tank 200 can be in the form of a steel welded spherical storage tank or the like; the low-temperature cold storage working fluid storage tank 400 and the medium-temperature cold storage working fluid storage tank 300 can be in the form of a single-capacity tank, a double-capacity tank, a full-capacity tank or the like; the cold storage working fluid includes but is not limited to methanol, methanol-water solution, propane or the like.

[0048] According to an embodiment provided by the present invention, the buffer device 100 includes a first heat exchange component 110 and a second heat exchange component 120, and the exhaust port of the medium-temperature cold storage working fluid storage tank 300, the heat release passage of the first heat exchange component 110 and the air inlet of the buffer storage tank 200 are connected in sequence to form a first gas passage; the exhaust port of the buffer storage tank 200, the heat release passage of the second heat exchange component 120 and the air inlet of the medium-temperature cold storage working fluid storage tank 300 are connected in sequence to form a second gas passage.

[0049] In this embodiment, when the top gas phase space of the low-temperature cold storage working medium storage tank 400 and the medium-temperature cold storage working medium storage tank 300 reaches the maximum design pressure during the energy release process, the slightly positive pressure breathing gas in the medium-temperature cold storage working medium storage tank 300 and the low-temperature cold storage working medium storage tank 400 is pressurized and cooled by the first heat exchange component 110 on the first gas passage, and then stored in the buffer storage tank 200 as a normal temperature high-pressure cold storage working medium. When the pressure of the top gas phase space of the low-temperature cold storage working medium storage tank 400 and the medium-temperature cold storage working medium storage tank 300 no longer increases, the first gas passage is closed.

[0050] When the top gas phase space of the low-temperature cold storage working medium storage tank 400 and the medium-temperature cold storage working medium storage tank 300 reaches the minimum design pressure during the energy storage process, the normal temperature high-pressure breathing gas stored in the buffer storage tank 200 is cooled and depressurized by the second heat exchange component 120 on the second gas passage, and then enters the medium-temperature cold storage working medium storage tank 300 and the low-temperature cold storage working medium storage tank 400 as the breathing gas in a slightly positive pressure state to maintain the gas phase space pressure of the two tanks not less than the set minimum value. When the top gas phase space pressure of the low-temperature cold storage working medium storage tank 400 and the medium-temperature cold storage working medium storage tank 300 no longer decreases, the second gas passage is closed.

[0051] It can be seen that in this embodiment, the first heat exchange component 110 and the second heat exchange component 120 are used to construct the first gas passage and the second gas passage respectively. In the energy release stage and the energy storage stage, the breathing gas and the cold storage medium flow in two completely independent passages.

[0052] In one embodiment, the second heat exchange assembly 120 may be a liquid-to-air heat exchanger, and the normal temperature and high pressure cold storage medium stored in the buffer storage tank 200 passes through the heat release path of the liquid-to-air heat exchanger, exchanges heat with the liquid air in the heat absorption path of the liquid-to-air heat exchanger, and then enters the medium temperature cold storage medium storage tank 300 and the low temperature cold storage medium storage tank 400 after cooling. In this process, part of the cold capacity of the liquid-to-air product will be consumed, and the operation process may cause the efficiency of the cold storage system to decrease.

[0053] According to another embodiment provided by the present invention, the exhaust port of the medium-temperature cold storage medium storage tank 300, the heat absorption path of the second heat exchange component 120, the heat release path of the first heat exchange component 110 and the air inlet of the buffer storage tank 200 are sequentially connected to form a first gas path. In this embodiment, the first heat exchange component 110 and the second heat exchange component 120 are used together to construct the first gas path, and only the second heat exchange component 120 is used to construct the second gas path, that is, in the energy release stage and the energy storage stage, the flow paths of the breathing gas and the cold storage medium are not completely independent.

[0054] When the top gas phase space of the low-temperature cold storage working fluid storage tank 400 and the medium-temperature cold storage working fluid storage tank 300 reaches the maximum design pressure during the energy release process, the slightly positive pressure breathing gas in the medium-temperature cold storage working fluid storage tank 300 and the low-temperature cold storage working fluid storage tank 400 is heated through the second heat exchange component 120 on the first gas passage, and then enters the first heat exchange component 110 for cooling and pressurization, and is stored in the buffer storage tank 200 in the state of normal temperature and high-pressure cold storage working fluid.

[0055] When the top gas phase space of the low-temperature cold storage working fluid storage tank 400 and the medium-temperature cold storage working fluid storage tank 300 reaches the minimum design pressure during the energy storage process, the normal temperature and high-pressure cold storage working fluid stored in the buffer storage tank 200 is cooled and depressurized by the second heat exchange component 120 on the second gas passage, and then enters the medium-temperature cold storage working fluid storage tank 300 and the low-temperature cold storage working fluid storage tank 400 in a slightly positive pressure state to maintain the gas phase space pressure of the two tanks not lower than the set minimum value.

[0056] In this embodiment, the second heat exchange component 120 includes at least three heat exchange passages, one for absorbing heat, one for releasing heat, and one for circulating heat exchange medium, so as to exchange heat with the absorbing heat passage or the releasing heat passage during energy release and energy storage. Methanol can be used as the heat exchange medium to recover the cold of the cold storage medium, thereby avoiding the waste of cold of the liquid air product caused by using a liquid-to-air heat exchanger.

[0057] According to an embodiment provided by the present invention, the second heat exchange component 120 includes a second heat exchanger 121, a low-temperature storage tank 122 and a medium-temperature storage tank 123, the outlet of the low-temperature storage tank 122, the heat exchange passage of the second heat exchanger 121 and the inlet of the medium-temperature storage tank 123 are connected in sequence, and the outlet of the medium-temperature storage tank 123, the heat exchange passage of the second heat exchanger 121 and the inlet of the low-temperature storage tank 122 are connected in sequence.

[0058] In this embodiment, when the top gas phase space of the low-temperature cold storage working medium storage tank 400 and the medium-temperature cold storage working medium storage tank 300 reaches the maximum design pressure during the energy release process, the slightly positive pressure breathing gas in the medium-temperature cold storage working medium storage tank 300 and the low-temperature cold storage working medium storage tank 400 enters the heat absorption path of the second heat exchanger 121, and performs heat exchange with the medium-temperature heat exchange medium in the heat exchange path of the second heat exchanger 121. The breathing gas releases cold energy to the medium-temperature heat exchange medium, and the breathing gas becomes normal-temperature breathing gas, which is pressurized and cooled by the first heat exchange component 110 and stored in the buffer storage tank 200 in a normal-temperature high-pressure state. In this process, the heat exchange path of the second heat exchanger 121 serves as a heat release path, so that the medium-temperature heat exchange medium is pumped out of the medium-temperature storage tank 123 by the medium-temperature heat exchange medium pump 124, absorbs the cold energy of the breathing gas through the second heat exchanger 121, and becomes a low-temperature heat exchange medium and enters the low-temperature storage tank 122, completing the cold energy recovery.

[0059] When the top gas phase space of the low-temperature cold storage working medium storage tank 400 and the medium-temperature cold storage working medium storage tank 300 reaches the minimum design pressure during the energy storage process, the normal temperature high-pressure breathing gas stored in the buffer storage tank 200 enters the heat release path of the first heat exchanger 111, and exchanges heat with the heat exchange medium in the heat exchange path. The breathing gas is cooled to a low temperature by the low-temperature heat exchange medium, and then reduced to a slightly positive pressure state, and then enters the medium-temperature cold storage working medium storage tank 300 to maintain the gas phase space pressure not lower than the set minimum value. In this process, the heat exchange path of the second heat exchanger 121 serves as a heat absorption path, so that the low-temperature heat exchange medium is pumped out of the low-temperature storage tank 122 by the low-temperature heat exchange medium pump 125, releases cold through the second heat exchanger 121, and enters the medium-temperature storage tank 123 in the state of medium-temperature heat exchange medium, completing the cycle.

[0060] In this embodiment, the heat exchange medium forms energy conversion storage of the heat exchange medium between the low-temperature storage tank 122 and the medium-temperature storage tank 123 through the second heat exchanger 121. The heat exchange medium absorbs the cold of the respiratory gas in the energy release stage and cools it down before entering the low-temperature storage tank 122. The heat exchange medium absorbs the heat of the respiratory gas in the energy storage stage and heats it up before entering the medium-temperature storage tank 123. The heat exchange between the respiratory gas and the heat exchange medium in the second heat exchanger 121 can ensure that there is no loss of heat exchange medium during the process of cooling the gas in the heat release path of the second heat exchanger 121 and heating the gas in the heat absorption path.

[0061] According to an embodiment provided by the present invention, the first heat exchange component 110 includes a first heat exchanger 111 and a gas compressor 112, and the heat release passage of the gas compressor 112 and the first heat exchanger 111 are sequentially connected along the airflow direction in the first gas passage. In this embodiment, when the first gas passage is constructed by the first heat exchange component 110 and the second heat exchange component 120, the slightly positive pressure breathing gas in the medium-temperature cold storage medium storage tank 300 and the low-temperature cold storage medium storage tank 400 first absorbs heat and heats up through the heat absorption passage of the second heat exchanger 121, enters the gas compressor 112 for pressurization, and then enters the heat release passage of the first heat exchanger 111 to absorb cold and cool down, and is stored in the buffer storage tank 200 in the state of normal temperature and high-pressure cold storage medium. When the first gas passage is constructed independently by the first heat exchange component 110, the slightly positive pressure breathing gas in the medium-temperature cold storage working fluid storage tank 300 and the low-temperature cold storage working fluid storage tank 400 is pressurized by the gas compressor 112, and then enters the heat release passage of the first heat exchanger 111 to absorb cold energy and cool down, and is then stored in the buffer storage tank 200 in the state of normal temperature and high-pressure cold storage working fluid.

[0062] In this embodiment, the gas compressor 112 can be a piston type, screw type or centrifugal type structure; the second heat exchanger 121 can adopt a water-cooled heat exchanger, which can be one or a combination of shell and tube structure, plate fin structure, winding tube structure, etc.

[0063] According to an embodiment provided by the present invention, the pipeline connecting the outlet of the medium-temperature cold storage medium storage tank 300 and the gas compressor 112 is provided with a first valve body 510, and the pipeline connecting the first heat exchanger 111 and the buffer storage tank 200 is provided with a second valve body 520. In this embodiment, the first valve body 510 and the second valve body 520 jointly control the opening and closing of the first gas passage.

[0064] When the gas phase space at the top of the medium-temperature cold storage working medium storage tank 300 and the low-temperature cold storage working medium storage tank 400 reaches the maximum design pressure during the energy release process, the first valve body 510 and the second valve body 520 are opened, and the slightly positive pressure gas passes through the gas compressor 112, the first heat exchanger 111 and the buffer storage tank 200 in the first gas passage in sequence, or the slightly positive pressure gas passes through the second heat exchanger 121, the gas compressor 112, the first heat exchanger 111 and the buffer storage tank 200 in the first gas passage in sequence. When the pressure of the gas phase space at the top of the medium-temperature cold storage working medium storage tank 300 and the low-temperature cold storage working medium storage tank 400 no longer increases, the first valve body 510 and the second valve body 520 are closed.

[0065] In this embodiment, the first valve body 510 and the second valve body 520 may be pneumatic or electric regulating valves.

[0066] According to an embodiment provided by the present invention, a pipeline connecting the buffer storage tank 200 and the second heat exchanger 121 is provided with a third valve body 530, and a pipeline connecting the second heat exchanger 121 and the inlet of the medium-temperature cold storage working medium storage tank 300 is provided with a fourth valve body 540. In this embodiment, the third valve body 530 can be used to control the on-off of the second gas passage, and the fourth valve body 540 can be a throttle valve.

[0067] When the gas phase space at the top of the medium-temperature cold storage medium storage tank 300 and the low-temperature cold storage medium storage tank 400 reaches the minimum design pressure during the energy storage process, the third valve body 530 and the fourth valve body 540 are opened, so that the normal temperature and high pressure cold storage medium stored in the buffer storage tank 200 passes through the second gas passage and passes through the second heat exchanger 121 for liquid-air cooling, and then passes through the fourth valve body 540 to throttle and reduce the pressure to a slightly positive pressure state, and then enters the medium-temperature cold storage medium storage tank 300 to maintain the gas phase space pressure not lower than the set minimum value. When the gas phase space pressure at the top of the medium-temperature cold storage medium storage tank 300 and the low-temperature cold storage medium storage tank 400 no longer decreases, the third valve body 530 and the fourth valve body 540 are closed.

[0068] In this embodiment, the third valve body 530 and the fourth valve body 540 may be pneumatic or electric regulating valves.

[0069] According to an embodiment provided by the present invention, the pipeline connecting the outlet of the low-temperature storage tank 122 and the second heat exchanger 121 is provided with a fifth valve body 550, the pipeline connecting the second heat exchanger 121 and the inlet of the medium-temperature storage tank 123 is provided with a sixth valve body 560, the pipeline connecting the outlet of the medium-temperature storage tank 123 and the second heat exchanger 121 is provided with a seventh valve body 570, and the pipeline connecting the second heat exchanger 121 and the inlet of the low-temperature storage tank 122 is provided with an eighth valve body 580.

[0070] In this embodiment, when the top gas phase space of the low-temperature cold storage working medium storage tank 400 and the medium-temperature cold storage working medium storage tank 300 reaches the maximum design pressure during the energy release process, the seventh valve body 570 and the eighth valve body 580 are opened, so that the medium-temperature heat exchange medium is pumped out from the medium-temperature storage tank 123 by the medium-temperature heat exchange medium pump 124, absorbs cold energy through the second heat exchanger 121, and enters the low-temperature storage tank 122 in a low-temperature state, completing the cold energy recovery. When the pressure of the top gas phase space of the low-temperature cold storage working medium storage tank 400 and the medium-temperature cold storage working medium storage tank 300 no longer increases, the seventh valve body 570 and the eighth valve body 580 are closed.

[0071] When the gas phase space at the top of the low-temperature cold storage tank 400 and the medium-temperature cold storage tank 300 reaches the minimum design pressure during the energy storage process, the fifth valve body 550 and the sixth valve body 560 are opened, so that the low-temperature heat exchange medium is pumped out of the low-temperature storage tank 122 by the low-temperature heat exchange medium pump 125, releases cold through the second heat exchanger 121, and enters the medium-temperature storage tank 123 in a medium-temperature state to complete the cycle. When the pressure of the gas phase space at the top of the low-temperature cold storage tank 400 and the medium-temperature cold storage tank 300 no longer decreases, the fifth valve body 550 and the sixth valve body 560 are closed.

[0072] In this embodiment, the fifth valve body 550 , the sixth valve body 560 , the seventh valve body 570 and the eighth valve body 580 may be pneumatic or electric regulating valves.

[0073] According to an embodiment provided by the present invention, a pipeline connecting the vent of the medium-temperature cold storage working fluid storage tank 300 and the vent of the low-temperature cold storage working fluid storage tank 400 is provided with a ninth valve body 590. In this embodiment, a ninth valve body 590 is provided on the pipeline connecting the medium-temperature cold storage working fluid storage tank 300 and the top of the low-temperature cold storage working fluid storage tank 400, and the ninth valve body 590 is in a normally open state, and can always balance the pressure at the top of the medium-temperature cold storage working fluid storage tank 300 and the top of the low-temperature cold storage working fluid storage tank 400, and the remaining valve bodies are all in a normally closed state, and are opened again according to the corresponding use requirements at different stages.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A zero-emission cold storage system for breathing air of a liquid air energy storage power station, characterized in that: It includes a buffer device, a buffer storage tank, a medium-temperature cold storage working fluid storage tank and a low-temperature cold storage working fluid storage tank, the air vent of the medium-temperature cold storage working fluid storage tank is connected with the air vent of the low-temperature cold storage working fluid storage tank, the exhaust port of the medium-temperature cold storage working fluid storage tank, the buffer device and the air inlet of the buffer storage tank are connected in sequence to form a first gas passage, the exhaust port of the buffer storage tank, the buffer device and the air inlet of the medium-temperature cold storage working fluid storage tank are connected in sequence to form a second gas passage; the slightly positive pressure breathing gas in the medium-temperature cold storage working fluid storage tank and the low-temperature cold storage working fluid storage tank is pressurized and cooled by the buffer device on the first gas passage, and then stored in the buffer tank in a state of normal temperature and high pressure; the normal temperature and high pressure breathing gas stored in the buffer tank is cooled and reduced in pressure by the buffer device on the second gas passage, and then enters the medium-temperature cold storage working fluid storage tank and the low-temperature cold storage working fluid storage tank as breathing gas in a slightly positive pressure state.

2. The zero-emission cold storage system for breathing air of a liquid air energy storage power station according to claim 1 is characterized in that: The buffer device includes a first heat exchange component and a second heat exchange component. The exhaust port of the medium-temperature cold storage working fluid storage tank, the heat release passage of the first heat exchange component and the air inlet of the buffer storage tank are connected in sequence to form the first gas passage; the exhaust port of the buffer storage tank, the heat release passage of the second heat exchange component and the air inlet of the medium-temperature cold storage working fluid storage tank are connected in sequence to form the second gas passage.

3. The zero-emission cold storage system for breathing air of the liquid air energy storage power station according to claim 2 is characterized in that: The exhaust port of the medium-temperature cold storage working medium storage tank, the heat absorption passage of the second heat exchange component, the heat release passage of the first heat exchange component and the air inlet of the buffer storage tank are connected in sequence to form the first gas passage.

4. The zero-emission cold storage system for breathing air of a liquid air energy storage power station according to claim 2 is characterized in that: The first heat exchange component includes a first heat exchanger and a gas compressor. The gas compressor and the heat release passage of the first heat exchanger are sequentially connected along the air flow direction in the first gas passage.

5. The zero-emission cold storage system for breathing air of a liquid air energy storage power station according to claim 3 is characterized in that: The second heat exchange component includes a second heat exchanger, a low-temperature storage tank and a medium-temperature storage tank. The outlet of the low-temperature storage tank, the heat exchange passage of the second heat exchanger and the inlet of the medium-temperature storage tank are connected in sequence, and the outlet of the medium-temperature storage tank, the heat exchange passage of the second heat exchanger and the inlet of the low-temperature storage tank are connected in sequence.

6. The zero-emission cold storage system for breathing air of a liquid air energy storage power station according to claim 4 is characterized in that: A first valve body is provided on the pipeline connecting the outlet of the medium-temperature cold storage working medium storage tank and the gas compressor, and a second valve body is provided on the pipeline connecting the first heat exchanger and the buffer storage tank.

7. The zero-emission cold storage system for breathing air of a liquid air energy storage power station according to claim 5, characterized in that: A pipeline connecting the buffer storage tank and the second heat exchanger is provided with a third valve body, and a pipeline connecting the second heat exchanger and the inlet of the medium-temperature cold storage working medium storage tank is provided with a fourth valve body.

8. The zero-emission cold storage system for breathing air of a liquid air energy storage power station according to claim 5, characterized in that: The pipeline connecting the outlet of the low-temperature storage tank and the second heat exchanger is provided with a fifth valve body, the pipeline connecting the second heat exchanger and the inlet of the medium-temperature storage tank is provided with a sixth valve body, the pipeline connecting the outlet of the medium-temperature storage tank and the second heat exchanger is provided with a seventh valve body, and the pipeline connecting the second heat exchanger and the inlet of the low-temperature storage tank is provided with an eighth valve body.

9. The zero-emission cold storage system for breathing air of a liquid air energy storage power station according to any one of claims 1 to 8, characterized in that: A ninth valve body is provided in the pipeline connecting the vent of the medium-temperature cold-storage working medium storage tank and the vent of the low-temperature cold-storage working medium storage tank.

10. A liquid air energy storage power station, characterized in that: A breathing gas zero-emission cold storage system for a liquid air energy storage power station comprising any one of claims 1 to 9.

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