Liquid air energy storage power station precooling system and energy storage power station

Abstract

The present invention relates to the field of liquid air energy storage, and provides a precooling system for a liquid air energy storage power station and an energy storage power station, wherein a precooling system for a liquid air energy storage power station comprises: a cold storage device, the cold storage device has a cold storage medium, the cold storage medium releases cold in the energy storage stage, and the cold storage medium releases heat in the energy release stage; a supplementary cooling circuit, the supplementary cooling circuit is connected to the cold storage device, and the supplementary cooling circuit exchanges heat with the cold storage medium. In order to solve the defect that the cold loss of the cold storage device in the prior art affects the working efficiency and even causes equipment damage, the precooling system for a liquid air energy storage power station provided by the present invention supplements the cold storage medium in the cold storage device by setting a supplementary cooling circuit connected to the cold storage device, so as to ensure that the liquid air energy storage power station can be supplemented with cold in time when it is running for a period of time or stopping for a period of time, and avoid the temperature change caused by the cold loss of the cold storage device, which leads to the loss of the cold storage medium steam and affects the performance of the device.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid air energy storage, and in particular to a liquid air energy storage power station precooling system and an energy storage power station. Background Art

[0002] Liquid air energy storage system (LAES) is based on low-temperature air liquefaction and cold storage technology, storing electrical energy in the form of low-temperature, low-pressure, high-density liquid air. Liquid air energy storage system is a new energy storage method that can achieve deep grid absorption and grid connection of new energy sources such as wind and light, reasonably absorb off-peak electricity and various forms of waste heat resources of the grid, and stably output various forms of energy such as cold, heat, electricity and industrial gas when needed.

[0003] Due to the large temperature difference between the low-temperature working fluid stored in the cold storage device of the liquid air energy storage system and the ambient temperature, although cold preservation measures have been taken, cold loss is still inevitable during the normal operation of the system. In addition, intermittent parking, especially long-term parking, will also cause cold loss, causing the system operating conditions to deviate significantly from the design conditions, and in severe cases, causing equipment damage. Summary of the invention

[0004] The present invention provides a liquid air energy storage power station precooling system and an energy storage power station, which are used to solve the defects in the prior art that the loss of cold capacity of the cold storage device affects the working efficiency, the loss of cold storage medium, the performance reduction, and even causes equipment damage. A supplementary cooling circuit is provided to provide supplementary cooling to the cold storage device to ensure the cold capacity and the safe operation of the equipment.

[0005] The present invention provides a liquid air energy storage power station precooling system, comprising:

[0006] A cold storage device, wherein the cold storage device has a cold storage medium, wherein the cold storage medium releases cold energy during the energy storage phase and releases heat during the energy release phase;

[0007] A supplementary cooling circuit is connected to the cold storage device, and the supplementary cooling circuit exchanges heat with the cold storage medium.

[0008] According to the precooling system of the liquid air energy storage power station provided by the present invention, the supplementary cooling circuit comprises:

[0009] A supplementary cooling pump, the supplementary cooling pump is connected to the cold storage device and is used to pump out the cold storage medium;

[0010] A first heat exchanger, wherein an inlet of a heat exchange side of the first heat exchanger is connected to the supplementary cooling pump, and an outlet of a heat exchange side of the first heat exchanger is connected to the cold storage device;

[0011] A liquid nitrogen storage tank is connected to the other heat exchange side of the first heat exchange side, so that the liquid nitrogen in the liquid nitrogen storage tank precools the cold storage medium.

[0012] The liquid air energy storage power station precooling system provided by the present invention further includes a first precooling circuit, which connects the liquid nitrogen storage tank and the cold storage device.

[0013] The liquid air energy storage power station precooling system provided by the present invention further includes a second precooling circuit, which connects the liquid nitrogen storage tank and the liquid expander of the energy storage circuit.

[0014] The liquid air energy storage power station precooling system provided by the present invention further includes a third precooling circuit, wherein the third precooling circuit connects the liquid nitrogen storage tank and the liquid air storage tank of the energy storage circuit.

[0015] The liquid air energy storage power station precooling system provided by the present invention further includes an impurity removal circuit, which is connected to the cold storage device and is used to precipitate insoluble impurities with a high freezing point in the cold storage medium entering the cold storage device.

[0016] According to the liquid air energy storage power station precooling system provided by the present invention, the impurity removal circuit includes:

[0017] A second heat exchanger, wherein the liquid nitrogen storage tank is connected to one heat exchange side of the second heat exchanger, and the cold storage medium is connected to an inlet of another heat exchange side of the second heat exchanger;

[0018] A filter device, wherein the outlet of the other heat exchange side of the second heat exchanger is connected to the filter device, and the filter device is connected to the cold storage device.

[0019] According to the precooling system of the liquid air energy storage power station provided by the present invention, the impurity removal circuit further includes:

[0020] A nitrogen storage tank connected to the filtering device and used for heating insoluble impurities in the filtering device;

[0021] A third heat exchanger, wherein one heat exchange side of the third heat exchanger is connected to the liquid nitrogen storage tank, and an inlet of another heat exchange side of the third heat exchanger is connected to the filtering device;

[0022] An impurity storage tank is connected to an outlet of another heat exchange side of the third heat exchanger.

[0023] According to the liquid air energy storage power station precooling system provided by the present invention, the impurity removal circuit also includes a first compressor, and the first compressor is connected between the filtering device and the third heat exchanger.

[0024] The present invention also provides a liquid air energy storage power station, comprising an energy storage circuit, an energy release circuit and the above-mentioned liquid air energy storage power station precooling system, wherein the energy storage circuit and the energy release circuit are both connected to the cold storage device.

[0025] The liquid air energy storage power station precooling system provided by the present invention provides a cooling circuit connected to the cold storage device to supplement the cold storage medium in the cold storage device, thereby ensuring that cold can be supplemented in time when the liquid air energy storage power station is running for a period of time or stopped for a period of time, thereby avoiding the temperature change caused by the cold loss of the cold storage device, resulting in the loss of cold storage medium steam and the impact on the performance of the device.

[0026] Furthermore, in the liquid air energy storage power station provided by the present invention, since it is provided with the liquid air energy storage power station precooling system as described above, it also has the various advantages as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are 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.

[0028] Figure 1 It is a connection diagram of the liquid air energy storage power station provided by the present invention;

[0029] Figure 2 It is a connection diagram of the internal structure of the cold storage device provided by the present invention.

[0030] Reference numerals:

[0031] 100: cold storage device; 110: supplementary cold circuit; 111: liquid nitrogen storage tank; 112: supplementary cold pump; 113: first heat exchanger; 101: first valve; 102: second valve; 103: third valve; 104: fourth valve; 105: fifth valve; 106: sixth valve; 107: seventh valve;

[0032] 120: liquefaction cold box; 130: gasification cold box; 140: cold storage medium cold tank; 141: cold pump; 150: cold storage medium hot tank; 151: heat pump; 121: first cold storage valve; 122: second cold storage valve; 131: third cold storage valve; 142: fourth cold storage valve; 143: fifth cold storage valve; 144: sixth cold storage valve; 152: seventh cold storage valve;

[0033] 200: impurity removal circuit; 201: working fluid pump; 202: second heat exchanger; 203: filtering device; 204: nitrogen storage tank; 205: first compressor; 206: third heat exchanger; 207: impurity storage tank; 210: eighth valve; 211: ninth valve;

[0034] 301: second compressor; 302: fourth heat exchanger; 303: air purification device; 304: liquid expander; 305: liquid air storage tank; 306: return gas loop; 307: gas phase loop; 308: heat storage device; 310: first precooling loop; 320: second precooling loop; 330: third precooling loop;

[0035] 400: liquid air pump; 401: fifth heat exchanger; 402: gas expander; 403: tenth valve; 404: eleventh valve. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] In the description of the embodiments of the present invention, it should be noted that the terms "upper", "lower", "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 limiting 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.

[0038] 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.

[0039] 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.

[0040] Liquid air energy storage technology is still in the transition stage from demonstration to commercial application. Since the air liquefaction part of the liquid air energy storage system is similar to the air separation unit, the air separation unit is generally equipped with a low-temperature gas expander to produce the required cooling capacity during the initial start-up process, and the cooling capacity production time is relatively long.

[0041] In addition, the core of the current liquid air energy storage system is the low-temperature cold storage device, which is generally divided into solid-phase cold storage, liquid-phase cold storage, and phase change cold storage according to the selected cold storage medium. Among them, the cost of using solid-phase cold storage medium is low, but the cold storage efficiency is low; phase change cold storage is still in the theoretical research stage; compared with solid-phase cold storage, liquid-phase cold storage technology is relatively mature and has a higher cold storage efficiency, but the cost of cold storage medium is higher, and the cold storage system has higher requirements for the purity and freezing point temperature of the medium during operation. In order to ensure the safe operation of the cold storage device, it is necessary to remove impurities with higher boiling points. Often, the higher the purity of the liquid phase medium and the fewer impurities, the higher its market price, and it is more difficult to purchase.

[0042] Combine the following Figure 1 and Figure 2 It should be understood that the following description is only an illustrative embodiment of the present invention and does not constitute a limitation on the present invention.

[0043] like Figure 1 As shown, the present invention provides a precooling system for a liquid air energy storage power station, comprising: a cold storage device 100 and a cold supplement circuit 110, the cold storage device 100 has a cold storage medium, the cold storage medium releases cold in the energy storage stage, and the cold storage medium releases heat in the energy release stage; the cold supplement circuit 110 is connected to the cold storage device 100, and the cold supplement circuit 110 exchanges heat with the cold storage medium.

[0044] In other words, the cold storage device 100 uses the cold storage medium to perform heat exchange between the energy storage stage and the energy release stage of the liquid air energy storage power station. When the cold capacity of the cold storage medium is insufficient, such as after a period of normal operation or long-term parking, the temperature of the cold storage medium in the cold storage device 100 will slowly increase. The cold storage medium is cooled by the supplementary cooling circuit 110 to ensure the temperature of the cold storage medium and reduce the impact of temperature changes on the loss of the cold storage medium, performance degradation, and equipment fatigue.

[0045] Specifically, the supplementary cooling circuit 110 includes a working medium circulation pipeline and a heat exchange pipeline. The working medium circulation pipeline circulates the cold storage working medium in the cold storage device 100 outside the cold storage device 100, and the heat exchange pipeline exchanges heat with the cold storage working medium in the working medium circulation pipeline through a cooling medium to cool down the cold storage working medium. After the cooling is completed, the cold storage working medium returns to the cold storage working medium through the working medium circulation loop to work.

[0046] Furthermore, in one embodiment of the present invention, the supplementary cooling circuit 110 includes: a supplementary cooling pump 112, a first heat exchanger 113 and a liquid nitrogen storage tank 111, the supplementary cooling pump 112 is connected to the cold storage device 100, and is used to pump out the cold storage working medium 201; the inlet of one heat exchange side of the first heat exchanger 113 is connected to the supplementary cooling pump 112, and the outlet of one heat exchange side of the first heat exchanger 113 is connected to the cold storage device 100; the liquid nitrogen storage tank 111 is connected to the other heat exchange side of the first heat exchanger 113, so that the liquid nitrogen in the liquid nitrogen storage tank 111 pre-cools the cold storage working medium.

[0047] That is to say, the supplementary cooling pump 112 forms a working medium circulation loop with one side of the first heat exchanger 113, and the liquid nitrogen storage tank 111 forms a heat exchange loop with the other side of the first heat exchanger 113. Specifically, the inlet of the supplementary cooling pump 112 is connected to the outlet of the cold storage working medium pipeline inside the cold storage device 100, the outlet of the supplementary cooling pump 112 is connected to one heat exchange side of the first heat exchanger 113, and one heat exchange side of the first heat exchanger 113 is connected to the inlet of the cold storage working medium pipeline inside the cold storage device 100. The outlet of the liquid nitrogen storage tank 111 is connected to the other heat exchange side of the first heat exchanger 113, and the nitrogen after heat exchange is discharged and recovered. Among them, a first valve 101 is set between the liquid nitrogen storage tank 111 and the first heat exchanger 113, which is used to switch the supplementary cooling loop 110. The first valve 101 can be a pneumatic or electric regulating valve to adjust the introduction rate of liquid nitrogen.

[0048] Continue to refer Figure 1In an optional embodiment of the present invention, the precooling system of the liquid air energy storage power station further includes a first precooling loop 310, and the first precooling loop 310 connects the liquid nitrogen storage tank 111 and the cold storage device 100. In the first start-up preparation stage, the first precooling loop 310 is opened, and low-temperature liquid nitrogen is introduced into the cold storage device 100 to precool the cold storage device 100 in advance. The introduced liquid nitrogen cools the cold storage device 100 and then is discharged from the cold storage device 100. For example, a third valve 103 is provided on the first precooling loop 310, and the third valve 103 is used to control the switch of the first precooling loop 310. The third valve 103 can be a pneumatic or electric regulating valve to adjust the liquid nitrogen introduction rate. Precooling the cold storage device 100 in advance can enable the cold storage device 100 to have the conditions for rapid startup, improve the working efficiency of the liquid air energy storage power station and shorten the startup time.

[0049] In addition, in another optional embodiment of the present invention, the precooling system of the liquid air energy storage power station also includes a second precooling loop 320, and the second precooling loop 320 connects the liquid nitrogen storage tank 111 and the liquid expander 304 of the energy storage loop. In the first start-up preparation stage, the second precooling loop 320 is opened, and the low-temperature liquid nitrogen is passed into the liquid expander 304 to precool the liquid expander 304 in advance. The introduced liquid nitrogen cools the liquid expander 304 and then discharges the liquid expander 304. For example, a fourth valve 104 is provided on the second precooling loop 320, and the fourth valve 104 is used to control the switch of the second precooling loop 320. The fourth valve 104 can be a pneumatic or electric regulating valve to adjust the liquid nitrogen introduction rate. Precooling the liquid expander 304 in advance can avoid damage to the operation of the equipment caused by vaporization due to temperature, and shorten the time of the energy storage process.

[0050] Continue to refer Figure 1 In other optional embodiments of the present invention, the precooling system of the liquid air energy storage power station also includes a third precooling loop 330, and the third precooling loop 330 connects the liquid nitrogen storage tank 111 and the liquid air storage tank 305 of the energy storage loop. In the first start-up preparation stage, the third precooling loop 330 is opened, and low-temperature liquid nitrogen is passed into the liquid air storage tank 305 to precool the liquid air storage tank 305 in advance. The introduced liquid nitrogen cools the liquid air storage tank 305 and then is discharged from the liquid air storage tank 305. For example, a fifth valve 105 is provided on the third precooling loop 330, and the fifth valve 105 is used to control the switch of the third precooling loop 330. The fifth valve 105 can be a pneumatic or electric regulating valve to adjust the liquid nitrogen introduction rate. The liquid air storage tank 305 is precooled in advance to make the liquid air storage tank ready for use.

[0051] Furthermore, in some embodiments of the present invention, the precooling system of the liquid air energy storage power station further includes a removal circuit 200, which is connected to the cold storage device 100 and is used to precipitate insoluble impurities with a high freezing point in the cold storage medium entering the cold storage device 100. In other words, the cold storage medium before entering the cold storage device 100 is filtered to precipitate insoluble impurities with a high freezing point, such as water and carbon dioxide. The purity of the cold storage medium is improved to ensure the safe operation of the cold storage device 100.

[0052] Furthermore, in an optional embodiment of the present invention, the impurity removal circuit 200 includes: a second heat exchanger 202 and a filter device 203, the liquid nitrogen storage tank 111 is connected to one heat exchange side of the second heat exchanger 202, and the cold storage medium is connected to the inlet of the other heat exchange side of the second heat exchanger 202; the outlet of the other heat exchange side of the second heat exchanger 202 is connected to the filter device 203, and the filter device 203 is connected to the cold storage device 100.

[0053] That is to say, the second heat exchanger 202 exchanges heat with the low-temperature liquid nitrogen in the liquid nitrogen storage tank 111 and the room-temperature cold storage working fluid containing impurities to reduce the temperature of the cold storage working fluid, and the insoluble impurities with a higher freezing point temperature in the cold storage working fluid form solid crystals, and the insoluble impurities of the solid crystals are filtered through the filter device 203 to complete the impurity removal. The cold storage working fluid after impurity removal is passed into the cold storage device 100 for operation. Of course, the impurity removal circuit 200 can also include a working fluid pump 201, which is arranged before the second heat exchanger 202 and is used to deliver the cold storage working fluid containing impurities into the second heat exchanger 202. Among them, a ninth valve 211 is arranged between the second heat exchanger 202 and the liquid nitrogen storage tank 111, and the ninth valve 211 is opened during the cold storage working fluid impurity removal process.

[0054] In addition, in some other embodiments of the present invention, the impurity removal circuit 200 also includes: a nitrogen storage tank 204, a third heat exchanger 206 and an impurity storage tank 207, the nitrogen storage tank 204 is connected to the filter device 203, and is used to heat the insoluble impurities in the filter device 203; one heat exchange side of the third heat exchanger 206 is connected to the liquid nitrogen storage tank 111, and the inlet of the other heat exchange side of the third heat exchanger 206 is connected to the filter device 203; the impurity storage tank 207 is connected to the outlet of the other heat exchange side of the third heat exchanger 206.

[0055] After the cold storage medium is impurity-free in the above embodiment, the medium pump 201 is turned off, and then the ninth valve 211 is closed to stop filtering the cold storage medium containing impurities. Nitrogen is used to discharge the insoluble impurities in the filter device 203. Specifically, nitrogen at room temperature is introduced into the nitrogen storage tank 204 and the filter device 203 to heat the insoluble impurities crystallized in the filter device 203, and the impurities are purged into the third heat exchanger 206. Liquid nitrogen is introduced into the third heat exchanger 206, and the liquid nitrogen cools and condenses the insoluble impurities into liquid, and stores them in the impurity storage tank 207, wherein the nitrogen is discharged from the impurity storage tank 207 for recovery.

[0056] Specifically, in the embodiment of the present invention, the impurity removal circuit 200 further includes a first compressor 205, which is connected between the filter device 203 and the third heat exchanger 206 to increase the pressure of the liquid impurities.

[0057] refer to Figure 1 The present invention provides a liquid air energy storage power station, including an energy storage circuit, an energy release circuit and the liquid air energy storage power station precooling system of the above embodiment, and the energy storage circuit and the energy release circuit are both connected to the cold storage device 100.

[0058] Specifically, the energy storage circuit includes a second compressor 301, a fourth heat exchanger 302, a heat storage device 308, an air purification device 303, a liquid expander 304 and a liquid-air storage tank 305, wherein the second compressor 301 is connected to the fourth heat exchanger 302, the fourth heat exchanger 302 is connected to the air purification device 303, the air purification device 303 is connected to the cold storage device 100, the cold storage device 100 is connected to the liquid expansion machine 304, and the liquid expansion machine 304 is connected to the liquid-air storage tank 305; wherein the heat storage device 308 is connected to the fourth heat exchanger 302.

[0059] In the preparation stage for the first start-up of the entire liquid air energy storage power station, it is necessary to open the third valve 103, the fourth valve 104 and the fifth valve 105 first, so that the low-temperature liquid nitrogen in the liquid nitrogen storage tank 111 can pre-cool the cold storage device 100, the liquid expander 304 and the liquid air storage tank 305.

[0060] Before the energy storage stage begins, the ninth valve 211 is opened, and the cold storage medium containing impurities is removed through the impurity removal circuit 200, and then introduced into the cold storage device 100 after the impurities are removed.

[0061] The working process of the energy storage stage is as follows: close the third valve 103, the fourth valve 104, the fifth valve 105 and the ninth valve 211, open the second valve 102, the seventh valve 107 and the sixth valve 106, the second compressor 301 compresses the external air at normal temperature and pressure and the return gas of the cold storage device 100 to medium temperature and high pressure, exchanges heat through the fourth heat exchanger 302, stores the heat in the heat storage device 308, and then passes the cooled compressed gas through the air purification device 303 to remove impurities with high freezing point temperatures such as water and carbon dioxide. Then it enters the cold storage device 100 to be cooled to a low temperature, and the cold storage medium in the cold storage device 100 absorbs heat and the temperature gradually increases. After the low-temperature and high-pressure air leaves the cold storage device 100, it is reduced in pressure and expanded by the liquid air expander, and then further expanded by the seventh valve 107 to generate low-temperature and low-pressure liquid air stored in the low-temperature liquid air storage tank 305. The low-temperature gaseous air in the liquid air storage tank 305 flows back to the cold storage device 100 through the gas phase loop 307 to provide cooling, and enters the second compressor 301 from the reflux gas loop 306 to complete the energy storage process of the liquid air energy storage power station.

[0062] The compressor can be driven by renewable energy electricity or off-peak electricity from the power grid.

[0063] The energy release circuit includes a liquid air pump 400, a fifth heat exchanger 401 and a gas expander 402. The inlet of the liquid air pump 400 is connected to the liquid air storage tank 305, and the outlet of the liquid air pump 400 is connected to the cold storage device 100. The cold storage device 100 is connected to the fifth heat exchanger 401, and the fifth heat exchanger 401 is connected to the gas expander 402. Among them, the fifth heat exchanger 401 is connected to the heat storage device 308.

[0064] The work flow of the energy release stage: the eleventh valve 404 and the tenth valve 403 are opened, the liquid air pump 400 pumps out low-temperature liquid air from the liquid air storage tank 305, and enters the cold storage device 100 to be heated to room temperature, and the cold storage medium in the cold storage device 100 absorbs the cold of the liquid air, completing the storage of the cold of the cold storage medium. The normal temperature and high pressure air passes through the fifth heat exchanger 401 to absorb the heat in the heat storage device 308 to heat up to medium temperature and high pressure air, and performs work in the gas expander 402, driving the generator to generate electricity and transmit it to the power grid, completing the energy release process of the liquid air energy storage device.

[0065] After a period of normal operation or long-term parking, the first valve 101 is opened, and the supplementary cooling circuit 110 of the precooling system begins to supplement the cooling of the cooling medium of the cooling device 100; liquid nitrogen is used to precool the cooling medium at a relatively high temperature to a low temperature and return it to the cooling device 100, and the vaporized nitrogen is recycled. Of course, the supplementary cooling circuit 110 can also be opened to supplement the cooling of the cooling device 100 during the energy storage stage and the energy release stage.

[0066] After the cold storage medium is free of impurities, the eighth valve 210 is opened to discharge the impurities in the filter device 203 into the impurity storage tank 207 .

[0067] For the cold storage device of the present invention, Figure 2 As shown, the cold storage device includes a liquefied cold box 120, a gasified cold box 130, a cold storage medium cold tank 140 and a cold storage medium hot tank 150. In the energy storage stage, the cold pump 141 pumps the cold storage medium in the cold storage medium cold tank 140 into the liquefied cold box 120, performs heat exchange with the incoming compressed air, and the cold storage medium after absorbing heat is stored in the cold storage medium hot tank 150; at the same time, the gas discharged from the gas phase loop 307 enters the cold storage medium cold tank 140 for cold release. In the energy release stage, the heat pump 151 pumps the cold storage medium in the cold storage medium hot tank 150 into the gasified cold box 130, performs heat exchange with the incoming liquid air, and the cold storage medium after losing heat is stored in the cold storage medium cold tank 140.

[0068] In the cold storage medium impurity removal stage, the cold storage medium after impurity removal comes out of the filtering device 203 and enters the cold storage medium cold tank 140 through the sixth cold storage valve 144 .

[0069] When the supplementary cooling circuit 110 is supplementing cooling, the supplementary cooling pump 141112 pumps the cold storage medium from the cold storage medium tank 140 or the cold storage medium hot tank 150 for supplementary cooling; that is, the supplementary cooling pump 141112 is connected to the cold storage medium tank 140 and the cold storage medium hot tank 150. Supplementary cooling is performed in the first heat exchanger, and the cold storage medium that has completed supplementary cooling returns to the cold storage medium tank 140 or the cold storage medium hot tank 150 through the fifth cold storage valve 143 or the seventh cold storage valve 152. That is, the first heat exchanger 113 is connected to the cold storage medium tank 140 and the cold storage medium hot tank 150;

[0070] In the first start-up precooling stage, the first cold storage valve 121, the second cold storage valve 122, the third cold storage valve 131 and the fourth cold storage valve 142 are opened, and the sixth cold storage valve 144 is closed, and liquid nitrogen flows through the third valve 103 into the counterflow air cold side and the cold side of the cold storage medium of the liquefied cold box 120, the cold pump 141, the cold storage medium cold tank 140 and the liquid air cold side of the gasification cold box 130 for precooling. In other words, the third valve 103 is connected to the liquefied cold box 120, the cold pump 141, the cold storage medium cold tank 140 and the gasification cold box 130 respectively.

[0071] The compressor can be of piston, screw or centrifugal structure, and the compressor includes one or more compressors, which are connected in series, in parallel or integrated into a compressor unit, and a cooler is arranged after each stage of the compressor; the heat exchanger of the present invention can be one or a combination of shell and tube structure, plate-fin structure, winding structure, etc.; the air purification device is filled with adsorbent, including but not limited to activated alumina, molecular sieve, etc.; the liquid expander can be single-stage or multi-stage; the liquid air storage tank can be a low-temperature atmospheric pressure storage tank, or a low-temperature pressure storage tank; the liquid air pump can be a piston or centrifugal The gas expander can be radial, axial or radial-axial, and the expander includes one or more expanders, which are connected in series, in parallel or integrated into an expansion unit. A compression heat utilization device is arranged in front of each stage of the expander. The liquid nitrogen storage tank can be a vertical or horizontal low-temperature storage tank. The working fluid pump can be a piston or centrifugal structure, and can be an in-tank submersible pump or an external pump. The nitrogen storage tank can be a vertical, horizontal storage tank or a spherical tank. The impurity storage tank can be a vertical or horizontal pressure storage tank or a normal pressure storage tank. The cold storage working fluid includes but is not limited to propane, methanol, methanol aqueous solution, etc.

[0072] The liquid air energy storage power station precooling system provided by the present invention provides a cooling circuit 110 connected to the cold storage device 100 to supplement the cold storage medium in the cold storage device 100, thereby ensuring that cold can be supplemented in time when the liquid air energy storage power station is running for a period of time or stopped for a period of time, thereby avoiding the temperature change caused by the cold loss of the cold storage device 100, resulting in the loss of cold storage medium steam and affecting the performance of the device.

[0073] Furthermore, in the liquid air energy storage power station provided by the present invention, since it is provided with the liquid air energy storage power station precooling system as described above, it also has the various advantages as described above.

[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 liquid air energy storage power station precooling system, characterized in that: include: A cold storage device, wherein the cold storage device has a cold storage medium, wherein the cold storage medium releases cold energy during the energy storage phase and releases heat during the energy release phase; A supplementary cooling circuit, the supplementary cooling circuit is connected to the cold storage device, and the supplementary cooling circuit exchanges heat with the cold storage medium; The supplementary cooling circuit comprises: A supplementary cooling pump, the supplementary cooling pump is connected to the cold storage device and is used to pump out the cold storage medium; A first heat exchanger, wherein an inlet of a heat exchange side of the first heat exchanger is connected to the supplementary cooling pump, and an outlet of a heat exchange side of the first heat exchanger is connected to the cold storage device; A liquid nitrogen storage tank, the liquid nitrogen storage tank being connected to the other heat exchange side of the first heat exchanger so that the liquid nitrogen in the liquid nitrogen storage tank precools the cold storage medium; It also includes a first pre-cooling circuit, wherein the first pre-cooling circuit connects the liquid nitrogen storage tank and the cold storage device; It also includes an impurity removal circuit, which is connected to the cold storage device and is used to precipitate insoluble impurities with a high freezing point in the cold storage medium entering the cold storage device.

2. The liquid air energy storage power station precooling system according to claim 1, characterized in that: It also includes a second pre-cooling circuit, which connects the liquid nitrogen storage tank and the liquid expander of the energy storage circuit.

3. The liquid air energy storage power station precooling system according to claim 1, characterized in that: It also includes a third pre-cooling circuit, which connects the liquid nitrogen storage tank and the liquid air storage tank of the energy storage circuit.

4. The liquid air energy storage power station precooling system according to claim 1, characterized in that: The impurity removal circuit comprises: A second heat exchanger, wherein the liquid nitrogen storage tank is connected to one heat exchange side of the second heat exchanger, and the cold storage medium is connected to an inlet of another heat exchange side of the second heat exchanger; A filter device, wherein an outlet of the other heat exchange side of the second heat exchanger is connected to the filter device, and the filter device is connected to the cold storage device.

5. The liquid air energy storage power station precooling system according to claim 4 is characterized in that: The impurity removal circuit also includes: A nitrogen storage tank connected to the filtering device and used for heating insoluble impurities in the filtering device; A third heat exchanger, wherein one heat exchange side of the third heat exchanger is connected to the liquid nitrogen storage tank, and an inlet of another heat exchange side of the third heat exchanger is connected to the filtering device; An impurity storage tank is connected to an outlet of another heat exchange side of the third heat exchanger.

6. The liquid air energy storage power station precooling system according to claim 5, characterized in that: The impurity removal circuit further includes a first compressor connected between the filtering device and the third heat exchanger.

7. A liquid air energy storage power station, characterized in that: It comprises an energy storage circuit, an energy release circuit and a liquid air energy storage power station precooling system according to any one of claims 1 to 6, wherein the energy storage circuit and the energy release circuit are both connected to the cold storage device.

Images