Air dehydration decarbonization purification method and system, liquid air energy storage power station

Abstract

The present application relates to the technical field of energy storage, and particularly relates to an air dehydration and decarburization purification method and system and a liquid air energy storage power station. The air purification unit of the system is suitable for being connected with an air compressor set of a liquid air energy storage system; in at least two-stage cold storage medium circulation loops, the air compressor set is connected with an LNG cold energy utilization unit through a first-stage cold storage medium loop, and the air purification unit is connected with the LNG cold energy utilization unit through a second-stage cold storage medium loop; in the air purification unit, a spray tower is connected with the air compressor set through a decarburization set; the spray tower is connected with the second-stage cold storage medium loop, and the spray tower is used for directly contacting air with the second-stage cold storage medium to dehydrate and cool the air flowing through. The system can fully utilize cold energy provided by the LNG cold energy utilization unit, and is applied to air spray dehydration. Compared with a traditional scheme, the system has the advantages of simple structure, small pressure loss in the air dehydration and decarburization process, low cost, and more suitable for large-scale application.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage, in particular to an air dehydration and decarburization purification method and system for coupling LNG cold energy utilization and a liquid air energy storage power station. BACKGROUND

[0002] Liquefied natural gas (LNG) is one of the important components of the clean energy supply system. LNG has extremely low temperature (minus 162 degrees Celsius), and contains huge cold energy. In the process of gasifying LNG for external delivery of natural gas, the LNG receiving terminal usually uses environmental heat (sea water, air) to heat LNG, and the valuable cold energy is discharged to the environment, which not only causes energy waste, but also causes "cold pollution" to the environment.

[0003] The commonly used cold energy utilization technology route of the LNG receiving station includes air separation, cold energy power generation, cold storage, etc. Due to the limitation of local industry demand for gas and cold energy, and the influence of LNG gasification quantity fluctuation of downstream users, the air separation, cold energy power generation and cold storage technologies are difficult to realize large-scale application in the LNG cold energy utilization scene.

[0004] As a new type of large-scale energy storage technology, liquid air energy storage is not limited by geographical conditions, and has the advantages of high energy storage density, green and environmentally friendly, and no pollution. In the process of preparing liquid air in the energy storage system, a compressor set is needed to compress air to high pressure, which consumes a large amount of electric energy. Therefore, how to greatly reduce the energy consumption of the air compression process and efficiently improve the efficiency of the energy storage system has been a technical problem to be solved in the energy storage field.

[0005] At present, in the field of energy storage, how to efficiently and reasonably utilize LNG cold energy in the liquid air energy storage system is still a technical problem to be solved. If a liquid air energy storage power station coupled with LNG cold energy utilization is considered to be built near the LNG receiving terminal, the first major problem is that the water content in the air is too high on the sea. In order to prevent the freezing of the heat exchanger pipe, the LNG cold energy cannot be used to cool the air to low temperature before air dehydration and decarburization, the power consumption of the first-stage compressor is high, and the efficiency of the energy storage system is improved little. The existing dehydration and decarburization methods mainly adopt adsorption method and freezing method. The adsorption method uses adsorbent to adsorb water in the air, and the molecular sieve purification system has high cost. The freezing method uses counterflow gas to freeze air in the switching heat exchanger, and the energy consumption of the self-cleaning process is large. SUMMARY

[0006] This invention provides an air dehydration, decarbonization, and purification method and system, as well as a liquid air energy storage power station, to address the technical problem of how to efficiently and rationally couple LNG cold energy into a liquid air energy storage system, which remains an urgent issue. By utilizing the abundant cold energy available at the LNG site to cool the air to a low temperature, the invention simultaneously achieves the functions of dehydration and decarbonization of the air. Compared with traditional air dehydration and decarbonization processes, this invention has advantages such as a simple system, low process pressure loss, and low cost.

[0007] This invention provides an air dehydration, decarbonization, and purification system, comprising an air purification unit and at least two stages of cold storage medium circulation loops. The air purification unit is adapted to connect to an air compressor unit of a liquid air energy storage system. The at least two stages of cold storage medium circulation loops include a primary cold storage medium loop and a secondary cold storage medium loop connected in parallel. The air compressor unit is connected to an LNG cold energy utilization unit through the primary cold storage medium loop, and the air purification unit is connected to the LNG cold energy utilization unit through the secondary cold storage medium loop. The air purification unit includes a spray tower and a decarbonization unit. The spray tower is connected to the air compressor unit through the decarbonization unit. The spray tower is connected to the secondary cold storage medium loop and is used to utilize the secondary cold storage medium to directly contact the air, thereby dehydrating and cooling the flowing air.

[0008] According to the present invention, an air dehydration and decarbonization purification system is provided, wherein the decarbonization unit includes at least one of at least two switching heat exchangers and a molecular sieve purifier.

[0009] The decarbonization unit includes at least two switching heat exchangers, each set of which is connected in parallel between the spray tower and the air compressor unit; each switching heat exchanger is connected to the primary cold storage medium circuit, and the primary cold storage medium circuits are connected in parallel with each other.

[0010] The decarbonization unit includes a molecular sieve purifier, the air compressor unit includes several connected stages of cryogenic air compressors, the spray tower is connected to the inlet of the first stage cryogenic air compressor, and the molecular sieve purifier is connected between any two stages of the cryogenic air compressors.

[0011] According to an air dehydration and decarbonization purification system provided by the present invention, the primary cold storage medium circuit includes a primary cold storage medium cold tank and a primary cold storage medium hot tank. A primary heat absorption pipeline and a primary heat release pipeline are respectively connected between the primary cold storage medium cold tank and the primary cold storage medium hot tank. Each of the switching heat exchangers is connected to the primary heat absorption pipeline, and the primary heat release pipeline is connected to the LNG vaporizer of the LNG cold energy utilization unit.

[0012] According to the air dehumidification and decarburization purification system provided by the application, the decarburization unit further comprises a heat pump air blowing and ice removing module connected to each of the switchable heat exchangers, and the heat pump air blowing and ice removing module is used for blowing air into the switchable heat exchanger to remove ice.

[0013] According to the air dehumidification and decarburization purification system provided by the application, the secondary cold storage medium loop comprises a secondary cold storage medium cold tank and a secondary cold storage medium hot tank, and a secondary heat absorption pipeline and a secondary heat release pipeline are respectively connected between the secondary cold storage medium cold tank and the secondary cold storage medium hot tank, the spray tower is connected to the secondary heat absorption pipeline, and the secondary heat release pipeline is connected with the natural gas superheater of the LNG cold energy utilization unit.

[0014] According to the air dehumidification and decarburization purification system provided by the application, the air purification unit further comprises a water solution concentration module installed on the secondary heat absorption pipeline and connected between the spray tower and the secondary cold storage medium hot tank.

[0015] According to the air dehumidification and decarburization purification system provided by the application, the air purification unit further comprises an air filter, the spray tower is connected to an air source through the air filter, and the air filter is used for pre-filtering air entering the spray tower.

[0016] According to the air dehumidification and decarburization purification system provided by the application, the air purification unit further comprises a water cooling tower connected between the air filter and the spray tower, and / or the spray tower is a multi-stage spray tower, each stage of the spray tower is connected in series between the air filter and the decarburization unit through an air inlet pipeline, each stage of the spray tower is connected to the secondary cold storage medium loop, and a medium return pipeline is connected between adjacent spray towers.

[0017] The application further provides a liquid air energy storage power station, which comprises an LNG cold energy utilization unit, an air dehumidification and decarburization purification system as described above connected to the LNG cold energy utilization unit, an energy storage module comprising a multi-stage compressor unit, a liquid expander, an air heat release side of a cold box, a liquid expander, a throttle valve, a gas-liquid separator and a liquid air storage tank connected in sequence, an inlet end of the multi-stage compressor unit being connected to an air purification unit of the air dehumidification and decarburization purification system, the multi-stage compressor unit being connected to the LNG cold energy utilization unit, and an energy release module comprising a multi-stage air expander unit, the liquid air storage tank being connected to the multi-stage air expander unit through an air heat absorption side of the cold box.

[0018] The application further provides an air dehumidification and decarburization purification method executed by the air dehumidification and decarburization purification system as described above, and the air dehumidification and decarburization purification method comprises the following steps.

[0019] The cold energy in the LNG cold energy utilization unit is sequentially absorbed by the cold storage medium in the at least two-stage cold storage medium circulation loop.

[0020] Both air and secondary cold storage medium are introduced into the spray tower to dehydrate and cool the air by directly contacting the air with the secondary cold storage medium, and the dehydrated air enters the decarbonization unit to realize decarbonization.

[0021] The air after decarbonization can be used to prepare compressed air, and the cold energy is transferred to the preparation process of the compressed air by using the primary cold storage medium.

[0022] The air dehydrating and decarbonizing purification system provided by the present application comprises an air purification unit and at least two-stage cold storage medium circulation loop. The air purification unit is suitable for connecting the air compressor unit of the liquid air energy storage system; the at least two-stage cold storage medium circulation loop comprises a primary cold storage medium loop and a secondary cold storage medium loop connected in parallel, the air compressor unit is connected to the LNG cold energy utilization unit through the primary cold storage medium loop, and the air purification unit is connected to the LNG cold energy utilization unit through the secondary cold storage medium loop; the air purification unit comprises a spray tower and a decarbonization unit, and the spray tower is connected to the air compressor unit through the decarbonization unit; the spray tower is connected to the secondary cold storage medium loop, and the spray tower is used to directly contact the air with the secondary cold storage medium to dehydrate and cool the air flowing through. The air dehydrating and decarbonizing purification system provided by the present application can fully utilize the cold energy provided by the LNG cold energy utilization unit, realize air spray dehydration in the spray tower, and has the advantages of simple structure, small pressure loss in the air dehydrating and decarbonizing purification process, low cost, and more suitable for large-scale application compared with the scheme of realizing air dehydrating and decarbonizing by using the adsorption method and the freezing method in the prior art.

[0023] Specifically, the air dehydrating and decarbonizing purification system provided by the present application can fully utilize the abundant cold energy resources in the LNG cold energy scene, use a medium such as alcohol-water solution as the secondary cold storage medium, so that it can directly contact and exchange heat with the air in the spray tower, thereby greatly improving the cooling effect of the air; and compared with the traditional air dehydrating and decarbonizing process, the process can greatly improve the air cooling effect, greatly improve the air dehydration amount and dehydration efficiency, and greatly reduce the pressure loss of the air purification process, which is more conducive to the improvement of the electric power conversion efficiency of the liquid air energy storage power station. At the same time, the system can greatly reduce the use amount of adsorbents such as molecular sieves, greatly reduce the switching frequency of the switching heat exchanger, and reduce the energy consumption of the air purification process, so as to replace the potential economic loss caused by long-term operation investment with one-time investment. The system has the advantages of high efficiency, environmental protection, safety, economy, etc.

[0024] The application further provides a liquid air energy storage power station, comprising an LNG cold energy utilization unit; the air dehydration and decarburization purification system; an energy storage module comprising a multi-stage compressor set, a liquid expander, an air heat release side of a cold box, the liquid expander, a throttle valve, a gas-liquid separator and a liquid air storage tank connected in sequence, an inlet end of the multi-stage compressor set being connected to the air purification unit, and the multi-stage compressor set being connected to the LNG cold energy utilization unit; and an energy release module comprising a multi-stage air expander set connected in sequence, the liquid air storage tank being connected to the multi-stage air expander set through an air heat absorption side of the cold box. The liquid air energy storage power station has all the advantages of the air dehydration and decarburization purification system, and details are not described herein again.

[0025] The application further provides an air dehydration and decarburization purification method, which is executed by the air dehydration and decarburization purification system, so that the air dehydration and decarburization purification method has all the advantages of the air dehydration and decarburization purification system, and details are not described herein again. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the present application or prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort.

[0027] Figure 1 is a structural schematic diagram of a liquid air energy storage power station provided by the application and adopting an air dehydration and decarburization purification system.

[0028] Figure 2 is one of structural schematic diagrams of an air dehydration and decarburization purification system provided by the application.

[0029] Figure 3 is another of structural schematic diagrams of an air dehydration and decarburization purification system provided by the application.

[0030] Figure 4 is a third of structural schematic diagrams of an air dehydration and decarburization purification system provided by the application.

[0031] Figure 5 is a fourth of structural schematic diagrams of an air dehydration and decarburization purification system provided by the application.

[0032] Reference signs:

[0033] 1, air filter; 2, air purification unit; 3, primary air cryogenic compressor; 4, pre-cooler before secondary compressor stage; 5, secondary air cryogenic compressor; 6, pre-cooler before tertiary compressor stage; 7, tertiary air cryogenic compressor; 8, cold box; 9, liquid expander; 10, throttle valve; 11, gas-liquid separator; 12, liquid air storage tank; 13, liquid air pump; 14, pre-heater before primary expander stage; 15, primary air turbine; 16, pre-heater before secondary expander stage; 17, secondary air turbine; 18, pre-heater before tertiary expander stage; 19, tertiary expander; 20, pre-heater before fourth expander stage; 21, fourth expander; 22, LNG vaporizer; 23, natural gas superheater; 24, primary cold storage medium circuit; 25, secondary cold storage medium circuit; 201, spray tower; 202, decarbonization unit; 203, secondary cold storage medium cold tank; 204, water solution concentration module; 205, secondary cold storage medium hot tank; 206, molecular sieve purifier; 207, water cooling tower; 208, primary spray tower; 209, secondary spray tower; 210, air inlet pipeline; 211, medium return pipeline; 221, switchable heat exchanger; 222, primary cold storage medium cold tank; 223, primary cold storage medium hot tank; 224, heat pump air blowing and deicing module. DETAILED DESCRIPTION

[0034] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be described clearly and completely below with reference to the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0035] The present application will be described below with reference to the drawings. Figures 1 to 5 The air dehydrating and decarbonizing purification system (hereinafter referred to as “air purification system” or “system”) of the present application, the liquid air energy storage power station (hereinafter referred to as “power station”) adopting the system, and the air dehydrating and decarbonizing purification method (hereinafter referred to as “air purification method” or “method”) based on the above system and power station will be described in detail.

[0036] Figure 1This document illustrates the specific equipment and piping connection structure of the air dehydration and decarbonization purification system described in this invention within a liquid air energy storage power station. The liquid air energy storage power station includes an LNG cold energy utilization unit, an air dehydration and decarbonization purification system, an energy storage module, and an energy release module. The air dehydration and decarbonization purification system is connected to the LNG cold energy utilization unit, thereby collecting and utilizing the cold energy from the LNG vaporization process in the air dehydration and decarbonization purification process, achieving efficient coupling between LNG cold energy and liquid air energy storage. The air dehydration and decarbonization purification system and the LNG cold energy utilization unit are described in detail below and will not be repeated here.

[0037] The energy storage module and the energy release module of this liquid air energy storage power station are connected. For example... Figure 1 As shown, the energy storage module includes a multi-stage compressor unit, a liquid expander 9, the air heat release side of the cold box 8, a throttle valve 10, a gas-liquid separator 11, and a liquid air storage tank 12. During the energy storage phase, the multi-stage compressor unit compresses the dehydrated and decarbonized clean air in multiple stages. The compressed air enters the cold box 8 for air liquefaction, and the liquefied liquid air is stored in the liquid air storage tank 12. The inlet of the multi-stage compressor unit is connected to the air purification unit 2 of the air dehydration and decarbonization purification system, thereby using the air purification unit 2 to purify the air entering the energy storage module, improving air cleanliness. The multi-stage compressor unit is connected to the LNG cold energy utilization unit, allowing the cold energy from the LNG vaporization process to be extracted using a cold storage medium and utilized in the pre-cooling process before air compression, significantly reducing compression power consumption and improving the system's electro-electric conversion efficiency. Furthermore, the energy storage module also utilizes the air heat release side of the cold box 8 to cool the compressed high-pressure air to a low temperature; the low-temperature high-pressure air is depressurized and expanded by the liquid expander 9 and the throttle valve 10, and enters the gas-liquid separator 11 in the form of a gas-liquid two-phase flow. The separated liquid air enters the liquid air storage tank 12 for storage, thereby completing the energy storage process of the energy storage module.

[0038] In some embodiments, such as Figure 1 As shown, the gas outlet of the gas-liquid separator 11 is connected to the inlet of the air dehydration and decarbonization purification system, allowing the backflowing air to mix with the air source energy entering the liquid air energy storage power station and re-participate in the energy storage process. The liquid outlet of the gas-liquid separator 11 is connected to the liquid air storage tank 12, allowing the separated liquid air to enter and be stored in the liquid air storage tank 12. Furthermore, the pipeline connecting the gas outlet of the gas-liquid separator 11 to the inlet of the air dehydration and decarbonization purification system can be connected to one of the air heat release sides of the cold box 8, enabling the recovery of cold energy carried in the backflowing air during the process of preparing liquid air from compressed air. This improves the air liquefaction rate and increases the operating efficiency of the liquid air energy storage power station.

[0039] In the liquid air energy storage power station described in this embodiment, such asFigure 1 As shown, the energy releasing module includes a plurality of air expanders connected in series. The liquid air storage tank 12 is connected to the plurality of air expanders through the air heat absorption side of the cold box 8, so that the liquid air can be preheated by absorbing heat in the cold box 8 before entering the air turbine or expander. In the energy releasing stage, the air heat absorption side inlet end of the cold box 8 is preferably connected to the liquid air storage tank 12 through the liquid air pump 13. The low-temperature and normal-pressure liquid air flowing out of the liquid air storage tank 12 is pressurized to high pressure by the liquid air pump 13, and then enters the cold box 8 to absorb heat and vaporize and superheat to normal temperature. The superheating is achieved by absorbing the environmental heat outside the liquid air energy storage power station or the surrounding low-grade heat source. The high-pressure gas after being heated enters the plurality of air expanders, realizes the step-by-step expansion of air and outputs shaft power to the outside, thereby completing the energy releasing process of the liquid air energy storage device.

[0040] As can be understood, in the liquid air energy storage power station described in the embodiments of the present application, the energy releasing module is preferably connected to the power grid through the generator, so that the shaft power output by the air expansion in the energy releasing stage drives the generator to generate electricity, thereby delivering electricity to the power grid, and realizing the reliable application of the liquid air energy storage power station. The generation of electricity by the liquid air energy storage power station is only one application mode. As can be understood, the power station can also be applied to other applications.

[0041] As can be understood, in the above-mentioned liquid air energy storage power station, the plurality of air compressors preferably includes a plurality of air low-temperature compressors connected in series, and for each added air low-temperature compressor 3, a pre-cooler before the compressor stage is connected in series before the air low-temperature compressor, so as to realize the step-by-step compression and multi-stage pre-cooling of air. For example Figure 1 As shown, the plurality of air compressors includes a first air low-temperature compressor 3, a second air low-temperature compressor 5 and a third air low-temperature compressor 7 connected in series through air pipes, and a second pre-cooler before the compressor stage is connected in series through an air pipe between the first air low-temperature compressor 3 and the second air low-temperature compressor 5, and a third pre-cooler before the compressor stage is connected in series through an air pipe between the second air low-temperature compressor 5 and the third air low-temperature compressor 7.

[0042] Similarly, in the above-mentioned liquid air energy storage power station, the plurality of air expanders preferably includes a plurality of air turbines or expanders connected in series, and a pre-heater before the expander stage is connected in series before each air turbine or expander, so as to realize the multi-stage heating and step-by-step expansion of air. For example Figure 1As shown, the multi-stage air expander set comprises a first-stage air turbine 15, a second-stage air turbine 17, a third-stage expander 19 and a fourth-stage expander 21 connected in series by air pipelines, and a first-stage expander pre-heater 14 is connected in series before the first-stage air turbine 15, a second-stage expander pre-heater 16 is connected in series by an air pipeline between the first-stage air turbine 15 and the second-stage air turbine 17, a third-stage expander pre-heater 18 is connected in series by an air pipeline between the second-stage air turbine 17 and the third-stage expander 19, and a fourth-stage expander pre-heater 20 is connected in series by an air pipeline between the third-stage expander 19 and the fourth-stage expander 21.

[0043] In some embodiments, preferably in the energy storage stage, the ambient temperature and pressure air is dehydrated and decarbonated by the air pre-treatment unit 2 of the air purification system and is pre-cooled to a low temperature. The purified air is compressed to high pressure by the multi-stage air compressor set. The cold energy generated in the LNG gasification process is introduced between the air low-temperature compressors of the multi-stage air compressor set to cool the air to a lower temperature. In the above process, the electricity for the air low-temperature compressors is renewable energy or off-peak electricity. Since the LNG gasification process is carried out 24 hours a day, and the gasification amount is determined by the gas load of the downstream user, the cold storage medium circulation of the air purification system needs to be correspondingly arranged with cold tanks and hot tanks to recover the LNG cold energy in stages and stably output. The specific connection structure of the cold storage medium circulation of each stage is described in detail below.

[0044] The following references are cited Figures 1 to 5 The specific structure of the air dehydration and decarbonation purification system described above is described in detail.

[0045] As Figure 1 As shown, the air purification system described in the embodiments of the present application comprises an air purification unit 2 and at least two-stage cold storage medium circulation loops. The air purification unit 2 is adapted to be connected to the air compressor set of the liquid air energy storage system, that is, the air purification unit 2 is connected between the inlet end of the air compressor set of the liquid air energy storage power station and the air source, for carrying out purification operations such as dehydration and decarbonation on the air entering the liquid air energy storage power station before compression, to improve the cleanliness of the air entering the liquid air energy storage power station.

[0046] The at least two-stage cold storage medium circulation loops comprise a first-stage cold storage medium loop 24 and a second-stage cold storage medium loop 25 connected in parallel. The air compressor set is connected to the LNG cold energy utilization unit through the first-stage cold storage medium loop 24, so that the cold energy from the LNG cold energy utilization unit is introduced through the first-stage cold storage medium loop 24 to pre-cool the air compressor. The air purification unit 2 is connected to the LNG cold energy utilization unit through the second-stage cold storage medium loop 25, so that the cold energy from the LNG cold energy utilization unit is introduced through the second-stage cold storage medium loop 25 to be applied to the air purification unit 2.

[0047] It can be understood that in the embodiment of the present application, the primary cold storage medium circuit 24 can also be connected to the LNG cold energy utilization unit and the air purification unit 2, so that the cold energy extracted from the LNG cold energy utilization unit by the primary cold storage medium circuit 24 is applied to the air purification unit 2. The cold storage medium circulating in the primary cold storage medium circuit 24 and the secondary cold storage medium circuit 25 is different, and thus is connected to different modules in the air purification unit 2. The specific connection mode is described in detail below.

[0048] It can be understood that the primary cold storage medium circuit 24 preferably includes a plurality of first sub-circuits and a plurality of second sub-circuits connected in parallel. The LNG cold energy utilization unit is connected to the air purification unit 2 through the first sub-circuits. The LNG cold energy utilization unit is connected to the energy storage modules of the power station through the plurality of second sub-circuits, and preferably is connected to the pre-coolers before each compression stage of the multi-stage air compressor set through the plurality of second sub-circuits. The parallel connection of the first sub-circuits and the second sub-circuits can ensure that the cold energy extracted from the LNG gasification process reaches each corresponding unit or module, avoiding heat loss during cold energy utilization and improving the cold energy utilization efficiency.

[0049] The embodiment of the present application takes into account that the LNG receiving terminal is located on the sea, and the average relative humidity of the air throughout the year is above 50%, and the air carries a large amount of water. If the liquid air energy storage power station coupled with the LNG cold energy utilization is to significantly improve the efficiency, the inlet air temperature of each stage of compressor needs to be low temperature, for example, below minus 50 degrees Celsius. Therefore, it is preferred to connect the air dehydration and decarburization purification system described in the embodiment of the present application before the multi-stage air compressor set of the energy storage module, and then use the LNG cold energy to cool the air to low temperature.

[0050] As shown in Figure 2 The air purification unit 2 described in the embodiment of the present application includes a spray tower 201 and a decarburization set 202. The spray tower 201 is connected to the air compressor set through the decarburization set 202. The decarburization set 202 is at least used for further removing carbon dioxide from the dehydrated air. The spray tower 201 is connected to the secondary cold storage medium circuit 25, that is, the secondary cold storage medium circuit 25 can directly introduce the secondary cold storage medium into the spray tower 201 to directly contact with the air. The spray tower 201 is at least used for directly contacting the air with the secondary cold storage medium to dehydrate and cool the air flowing therethrough. The air dehydration and decarburization purification system described in the present application can fully utilize the cold energy provided by the LNG cold energy utilization unit to realize air spray dehydration in the spray tower 201. Compared with the scheme of realizing air dehydration and decarburization by using adsorption method and freezing method in the prior art, the system has the advantages of simple structure, small pressure loss in the air dehydration and decarburization purification process, low cost, and is more suitable for large-scale application.

[0051] Specifically, the air dehydration and decarburization purification system described in the present application can make full use of the rich cold energy resources under the LNG cold energy scenario, use, for example, an alcohol aqueous solution as a secondary cold storage medium, so that it can be in direct contact with air in the spray tower 201 for heat exchange, thereby greatly improving the cooling effect of the air; and compared with the traditional air dehydration and decarburization process, the process can greatly improve the air cooling effect, greatly improve the air dehydration amount and dehydration efficiency, and greatly reduce the pressure loss of the air purification process in the process, which will be more conducive to the application of the processed air in various types of liquid air energy storage power stations, such as liquid air energy storage power stations, and will be more conducive to improving the electric power conversion efficiency. At the same time, the system can greatly reduce the use amount of adsorbents such as molecular sieves, greatly reduce the switching frequency of the switching heat exchanger 221, and reduce the energy consumption of the air purification process, so as to replace the economic potential loss brought by long-term operation investment with one-time investment. It has the advantages of high efficiency, environmental protection, safety, economy and the like.

[0052] It can be understood that the LNG cold energy utilization unit described in the embodiment of the present application includes an LNG vaporizer 22 and a natural gas superheater 23. The LNG vaporizer 22 and the natural gas superheater 23 are connected in series between an LNG inlet source and an NG output end in the direction of LNG inlet, the LNG inlet source is connected to external LNG, and the NG output end is connected to external NG. LNG represents liquefied natural gas, and NG represents gaseous natural gas.

[0053] It can be understood that the primary cold storage medium circuit 24 is connected to the LNG vaporizer 22 and the multi-stage air compressor set; and in some specific embodiments, the primary cold storage medium circuit 24 is connected to the LNG vaporizer 22 and the decarburization unit 202. Therefore, in order to ensure reliable transfer of cold energy, avoid cold energy loss and reliably improve heat exchange efficiency, the primary cold storage medium flowing in the primary cold storage medium circuit 24 preferably uses propane as the main component of the cold storage medium.

[0054] It can be understood that the secondary cold storage medium circuit 25 is connected to the natural gas superheater 23 and the spray tower 201. And in order to safely realize the direct contact heat exchange between air and the secondary cold storage medium, the secondary cold storage medium flowing in the secondary cold storage medium circuit 25 preferably uses an alcohol aqueous solution prepared by mixing at least one of methanol, ethylene glycol and propylene glycol with water in different proportions. Salt water solution can also be used as a secondary cold storage medium, but because the salt water solution has a certain corrosiveness, it can easily affect the service life of stainless steel equipment, so the salt water solution is not the best choice.

[0055] In some embodiments, as Figure 2 and Figure 3As shown, the decarbonization unit 202 includes at least one of at least two switching heat exchangers 221 and a molecular sieve purifier 206. The specific selection of the equipment for the decarbonization unit 202 can be based on the material of the secondary cold storage medium introduced into the spray tower 201 during the air purification process. Details are as follows.

[0056] In some specific embodiments, an inorganic salt aqueous solution or a polyol aqueous solution as described above is selected corresponding to the secondary cold storage medium, such as... Figure 2 As shown, the preferred decarbonization unit 202 includes at least two switching heat exchangers 221. The air is further cooled using the parallel-connected switching heat exchangers 221, and carbon dioxide is removed during the cooling process. Each set of switching heat exchangers 221 is connected in parallel between the spray tower 201 and the air compressor unit. Each switching heat exchanger 221 is connected to a primary cold storage medium circuit 24, and the primary cold storage medium circuits 24 are connected in parallel. That is, each primary cold storage medium circuit 24 includes several parallel first sub-circuits, the number of which is the same as the number of switching heat exchangers 221. This allows each primary cold storage medium to be introduced into its corresponding switching heat exchanger 221. Under the cooling energy of the primary cold storage medium, the switching heat exchangers 221 rapidly cool the air and freeze the carbon dioxide contained in the air within the heat exchanger, achieving deep decarbonization of the air.

[0057] In some specific embodiments, such as Figure 2 As shown, the primary cold storage medium circuit 24 includes a primary cold storage medium cold tank 222 and a primary cold storage medium hot tank 223. The functions of the cold and hot tanks have been explained above and will not be repeated here. A primary heat absorption pipeline and a primary heat release pipeline are connected between the primary cold storage medium cold tank 222 and the primary cold storage medium hot tank 223, respectively. The flow direction of the primary heat absorption pipeline is that the primary cold storage medium flows from the primary cold storage medium cold tank 222 to the primary cold storage medium hot tank 223 and is heated; the flow direction of the primary heat release pipeline is that the primary cold storage medium flows from the primary cold storage medium hot tank 223 to the primary cold storage medium cold tank 222 and is cooled. Each switching heat exchanger 221 is connected to the primary heat absorption pipeline to cool the air through heat exchange between the air and the primary cold storage medium, corresponding to the primary cold storage medium absorbing heat and heating up. The primary heat release pipeline is connected to the LNG vaporizer 22 of the LNG cold energy utilization unit to use the primary cold storage medium to remove the cold energy in the LNG vaporization process, improve the LNG vaporization efficiency, and utilize the cold energy in the switching heat exchanger 221.

[0058] Similarly, the secondary cold storage medium loop 25 includes a secondary cold storage medium cold tank 203 and a secondary cold storage medium hot tank 205. The functions of the cold and hot tanks have been explained above and will not be repeated here. A secondary heat absorption pipeline and a secondary heat release pipeline are connected between the secondary cold storage medium cold tank 203 and the secondary cold storage medium hot tank 205, respectively. The flow direction of the secondary heat absorption pipeline is that the secondary cold storage medium flows from the primary cold storage medium cold tank 222 to the secondary cold storage medium hot tank 205 and is heated; the flow direction of the secondary heat release pipeline is that the secondary cold storage medium flows from the secondary cold storage medium hot tank 205 to the secondary cold storage medium cold tank 203 and is cooled. The spray tower 201 is connected to the secondary heat absorption pipeline to allow the secondary cold storage medium to be introduced into the spray tower 201, enabling direct heat exchange between the air and the secondary cold storage medium. The moisture and heat in the air are carried back to the secondary cold storage medium hot tank 205 by the secondary cold storage medium. The secondary heat release pipeline is connected to the natural gas superheater 23 of the LNG cold energy utilization unit to use the secondary cold storage medium to remove the cold energy in the LNG gasification process, improve the LNG gasification efficiency, and utilize the cold energy in the spray tower 201.

[0059] In some specific embodiments, such as Figure 2 As shown, the decarbonization unit 202 also includes a heat pump blowing de-icing module. The heat pump blowing de-icing module is connected to each switching heat exchanger 221. The heat pump blowing de-icing module is used to blow air into the switching heat exchanger 221 for de-icing, to prevent the temperature of the switching heat exchanger 221 from being too low and affecting the subsequent continuous decarbonization, thereby improving the system's working efficiency and quality.

[0060] In some specific embodiments, such as Figure 2 As shown, the air purification unit 2 also includes an aqueous solution concentration module 204. The aqueous solution concentration module 204 is installed in the secondary heat absorption pipeline and connected between the spray tower 201 and the secondary cold storage medium heat tank 205. During the circulation of the secondary cold storage medium in the secondary cold storage medium loop 25, the solution composition of the secondary cold storage medium will change significantly after multiple energy storage stages of system operation. The aqueous solution concentration module 204 can concentrate the solution to its initial concentration, preventing the increase in water content from affecting the solution physical properties of the secondary cold storage medium, thus impacting the cold energy recovery efficiency and the overall system efficiency and quality.

[0061] In some specific embodiments, such as Figure 2 As shown, the air purification unit 2 also includes an air filter 1. The spray tower 201 is connected to the air source through the air filter 1; that is, the air filter 1 is installed at the gas inlet end of the spray tower 201. The air filter 1 is used to pre-filter the air entering the spray tower 201.

[0062] like Figure 2As shown, during the energy storage stage of the power station, the air is filtered by the air filter of the air purification system to remove some impurities in the air. The filtered air enters the spray tower 201, in which the secondary cold storage medium is sprayed, and the air exchanges heat with the cold storage medium directly. The dew point of the air at the gas outlet of the spray tower 201 is reduced to below -30°C, greatly reducing the water-carrying capacity of the air. Then the air enters the two sets of switching heat exchangers 221 to realize decarbonization and deep dehydration. The air flowing through the spray tower 201 has transferred most of the water to the secondary cold storage medium, so the secondary cold storage medium is preferably an inorganic salt solution or a polyhydric alcohol solution. After the operation of the power station in multiple energy storage stages, the secondary cold storage medium in the air purification system has a large change in the composition of water in the solution, so the water solution concentration module 204 is used to concentrate the water solution to the initial concentration to prevent the increase of the water component from causing the freezing point temperature of the solution to rise, thereby avoiding the freezing of the water solution during the cold storage process and affecting the recovery of LNG cold energy.

[0063] Since the system described in the embodiment is installed at the front of the stage of the multi-stage air compressor unit of the power station, the process pressure loss of the system is required to be low. Therefore, the switching heat exchanger 221 is preferably designed to be large in size. The primary cold storage medium in the switching heat exchanger 221 further cools the air and dehydrates and decarbonizes the air. The air after dehydration and decarbonization and pre-cooling by the system can enter the multi-stage air compressor unit to continue the energy storage stage of the liquid air energy storage system.

[0064] It should be noted that the water-carrying capacity of the air after dehydration by the spray tower 201 is very low, so the amount of ice in the switching heat exchanger 221 is small, thereby realizing a long air treatment time. Figure 2 As shown, there are two switching heat exchangers 221, and each heat exchanger processes air for half the time of the energy storage stage. During the air purification process, the carbon dioxide component in the air is also frozen in the switching heat exchanger 221. After the end of the energy storage stage, the ambient air is introduced and heated by the heat pump in the heat pump air blowing and ice removal module 224, and the hot air is blown back to the switching heat exchanger 221 by the air blower to perform the ice removal process.

[0065] As can be seen from the above, Figure 3 The air purification system shown not only realizes the dehydration and decarbonization of the air, but also greatly reduces the pressure loss in the above process, so that it has a small effect on the efficiency of the entire power station. Moreover, the system can fully utilize the rich cold energy of the LNG cold energy utilization unit to purify the air, thereby greatly reducing the investment cost and use cost of the air purification unit 2 in the traditional liquid air energy storage system. In addition, the air purification system can actually be constructed as an air pretreatment device with high efficiency, environmental protection, safety, and economy.

[0066] It can be understood that the above-mentioned switching heat exchanger 221 can be one or a combination of a shell-and-tube structure, a plate-fin structure, a spiral pipe structure, etc.

[0067] In some embodiments, based on the above-mentioned air purification system, corresponding to the case of using a methanol aqueous solution with a concentration of 62wt% (weight percent) to 75wt% as the secondary cold storage working medium, the freezing point temperature of such a solution is as low as minus 69 degrees Celsius, and the air dew point temperature in the spray tower 201 can be reduced to below the air admission dew point temperature of the cold box 8 by direct cooling, for example, below minus 65 degrees Celsius, so that the air after dehydration and cooling by the spray tower 201 meets the requirements of the liquid air energy storage power station for the water content of the purified air, and therefore there is no need to additionally arrange the switching heat exchanger 221 and the heat pump air blowing deicing system and related equipment. Moreover, since methanol is more volatile, and the separate spray tower 201 cannot completely freeze and remove carbon dioxide, a molecular sieve purifier 206 is added, as shown in Figure 4 That is, the above-mentioned decarburization unit 202 includes the molecular sieve purifier 206. The multi-stage air compressor unit includes a plurality of stages of air low-temperature compressors connected in series, the spray tower 201 is connected to the inlet end of the first stage of air low-temperature compressors 3, and the molecular sieve purifier 206 is connected between any two stages of air low-temperature compressors.

[0068] It can be understood that since methanol is more volatile, a small amount of methanol is inevitably carried out of the spray tower 201, and therefore a set of molecular sieve purifiers 206 is preferably connected to the rear end of the first stage of air low-temperature compressors 3. The molecular sieve purifier 206 is used to remove organic impurities and carbon dioxide contained in the air. Of course, the molecular sieve purifier 206 can be arranged at the rear of any stage of air low-temperature compressors 3, but it is not recommended to be arranged at the front of the first stage of air low-temperature compressors 3, because the methanol water can freeze the air to below minus 65 degrees Celsius, at which the air temperature is lower than the triple-point temperature of carbon dioxide, but since the carbon dioxide concentration is extremely low, the carbon dioxide molecules cannot form dry ice by clustering, and if the molecular sieve purifier 206 is connected at the front of the first stage of air low-temperature compressors 3, the carbon dioxide concentration in the pores of the molecular sieve increases during the process of the molecular sieve adsorbing air, which easily forms dry ice locally, damages the pores of the molecular sieve, affects the reuse of the molecular sieve purifier 206, and has a certain impact on the system efficiency.

[0069] In the above-mentioned arrangement of replacing the switching heat exchanger 221 with the molecular sieve purifier 206, the dehydration and decarburization process of the air is basically the same as the above-mentioned arrangement of using the switching heat exchanger 221 as the decarburization unit 202, and the only difference is that the air purification system does not need to additionally use the switching heat exchanger 221 for secondary freezing and cooling of the air. The pressure loss of the air purification system is smaller, which is more conducive to improving the efficiency of the liquid air energy storage system.

[0070] It should be noted that in the air purification system described in the embodiments of the present application, the decarburization unit 202 can also be selected as a combination of the above two, that is, the spray tower 201, the switching heat exchanger 221 and the molecular sieve purifier 206 are combined and connected, depending on the allowable air vacuum degree of the primary air low-temperature compressor 3 of the liquid air energy storage power station and the allowable process pressure loss of the air purification system in the design scheme. Preferably, the spray tower 201 and the switching heat exchanger 221 are connected at the front of the primary air low-temperature compressor 3, and the molecular sieve purifier 206 is connected at the rear of the primary air low-temperature compressor 3, the spray tower 201 is used for deep dehydration of air, the switching heat exchanger 221 is used for secondary cooling and removal of carbon dioxide of air, and the molecular sieve purifier 206 is used for deep decarburization and dealcoholization of air, so as to achieve more efficient and more thorough air purification.

[0071] It can be understood that if the conventional adsorption method is directly used to pretreat air in front of the multi-stage air compressor unit, a large amount of adsorbent needs to be used due to the low air pressure, large volume and high water carrying capacity, and in the desorption process of the adsorbent, electric energy needs to be used to heat the regenerated air, thereby consuming more energy and materials, which is not conducive to the large-scale promotion and application of the liquid air energy storage power station coupled with LNG cold energy utilization. The air purification system described in the embodiments of the present application combines the spray tower 201 to realize direct heat exchange and dehydration of air and cold storage medium, which not only can cool the air to 2-5 degrees Celsius through low-grade cold energy, but also sets the gas-liquid separator 11 in the power station, so that the compressed air is used for air purification again after removing part of the condensed water through gas-liquid separation, which can effectively reduce the amount of adsorbent; and compared with the conventional adsorption method, the process pressure of the system described in the embodiments of the present application can be greatly reduced, which can effectively avoid the invalid increase of the total pressure ratio of the air compressor unit, thereby improving the overall efficiency of the liquid air energy storage power station.

[0072] It can be understood that if the heat exchanger is directly used to remove the moisture in the air by the traditional freezing method, the traditional air pretreatment link is earliest applied to the air separation device. In the running process, the moisture in the air is frozen in the heat exchanger, and after a period of work, the backflow gas is heated by the electric heater, and the heat exchanger is defrosted by backblowing. Since the air processing capacity of the power station is much higher than that of the air separation device, if the above-mentioned freezing method is used to remove the moisture in the air, more heat exchangers need to be arranged to realize the air dehydration and decarburization function, and the liquid air energy storage power station actually does not have a large amount of clean backflow gas, which needs to be additionally extracted from the rear of the compressor, which consumes a lot of resources and affects the overall efficiency of the system, and the control system is relatively complex, and the overall economic performance of the liquid air energy storage system is poor. The air purification system described in the embodiment of the present application combines the spray tower 201 to realize the direct heat exchange and dehydration of air and cold storage medium, so that the stage gas is not additionally extracted, the resource waste is reduced, the overall efficiency of the power station can be greatly improved, and the control logic of the whole power station is simple, which has high economic performance and practicality.

[0073] In some embodiments, some water solution concentration modules 204 (such as membrane separation technology) have cleanliness requirements for the aqueous solution of the secondary cold storage medium, in order to further improve the cleanliness of the sprayed aqueous solution, such as Figure 2 As shown, the air purification unit 2 also includes a water cooling tower. On the basis of the air purification unit 2 described in the above embodiments, the water cooling tower is connected between the air filter and the spray tower 201. The water cooling tower is connected with a cooling water circuit, and the cooling water circuit is connected with an external water source. The water cooling tower is used to wash the air with cooling water, so that pre-removal of impurities can be performed before air dehydration, thereby reducing impurities in the air, and further reducing impurities in the alcohol aqueous solution, and reducing the influence of impurities in the alcohol aqueous solution on the separation performance of the water solution concentration module 204.

[0074] It can be understood that the air purification system of the embodiment of the present application increases the cleanliness of the alcohol aqueous solution by using the water cooling tower, which can further reduce air impurities and make the water solution concentration module 204 more easily perform the concentration process. However, it should be noted that if the cooling water temperature is too high, it may increase the water carrying capacity of the air, and thus increase the power consumption of the water solution concentration module 204, therefore, the cooling water is preferably cooled to 5-10 degrees Celsius by using the residual cold energy of the LNG cold energy utilization unit, and then the spray cooling water is used. This setting can pre-cool the air and reduce the water carrying capacity of the air entering the later spray tower 201.

[0075] In some embodiments, if the cold energy provided by the LNG cold energy utilization unit is insufficient, preferably, on the basis of the air purification system described above, the spray tower 201 is set as a multi-stage spray tower 201. Each stage of the spray tower 201 is connected in series between the air filter and the decarbonization unit 202 through the air inlet pipeline 210. Each stage of the spray tower 201 is connected to the secondary cold storage medium loop 25, and the medium return pipeline 211 is connected between adjacent spray towers 201. For example, on the basis of the air purification system and the system structure formed by the combination thereof shown in Figure 3 、 Figure 4 and Figure 5 , a first-stage spray tower 208 is additionally arranged in front of the original spray tower 201, that is, as shown in ​ , the spray tower 201 includes a first-stage spray tower 208 and a second-stage spray tower 209. The alcohol aqueous solution is sprayed in the second-stage spray tower 209, and then part of the alcohol aqueous solution is returned to the first-stage spray tower 208. Through the segmented cooling, the setting avoids the absorption of more high-grade cold energy by the water in the air, so that more high-grade cold energy carried by the secondary cold storage medium is transmitted to the air, the outlet air temperature of the second-stage spray tower 209 is lower, the LNG cold energy utilization rate of the entire power plant is higher, and the effects of the heat exchange between the alcohol aqueous solution and the air and the pressure loss in the purification process on the system performance can be comprehensively considered.

[0076] It should be noted that the structure of the cold water tower and the multi-stage spray tower 201 described above can be applied to the air purification system provided with the two types of decarbonization units 202 described above.

[0077] It should be noted that at least one air purification system has all the related equipment described above, and in particular, the molecular sieve purifier 206 described above can be applied to all the air purification systems described above. The role of the molecular sieve purifier 206 does not lie in dehydrating the air, but in ensuring that the content of carbon dioxide and related organic matters in the air entering the power plant and the cold box 8 meets the standard.

[0078] The air dehydration and decarbonization purification method provided by the present application will be described below. The air dehydration and decarbonization purification method described below can be correspondingly referred to the air dehydration and decarbonization purification system described above.

[0079] The air dehydration and decarbonization purification method described in the embodiments of the present application is executed by the air dehydration and decarbonization purification system described above, which makes the air dehydration and decarbonization purification method have all the advantages of the air dehydration and decarbonization purification system described above, which will not be described here again.

[0080] The method at least includes the following steps.

[0081] Step one, using the cold storage medium in the at least two-stage cold storage medium circulation loop to sequentially absorb the cold energy in the LNG cold energy utilization unit.

[0082] Step two, air and secondary cold storage medium are both introduced into the spray tower 201 to dehydrate and cool the air by directly contacting the air with the secondary cold storage medium, and the dehydrated air enters the decarbonization unit 202 to realize decarbonization.

[0083] Step three, the decarbonized air can be used to prepare compressed air, and the cold energy is transferred to the preparation process of the compressed air by using the primary cold storage medium.

[0084] It can be understood that the specific process of each step of the above method has been described in detail in the specific operation process of the above system, and will not be repeated here.

[0085] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of each embodiment of the present application.

Claims

1. An air dehydration decarbonation purification system characterized by, The air purification unit (2) is connected with an air compressor set of a liquid air energy storage system, and at least two-stage cold storage medium circulation loops including a first-stage cold storage medium loop (24) and a second-stage cold storage medium loop (25) are connected in parallel, the air compressor set is connected with an LNG cold energy utilization unit through the first-stage cold storage medium loop (24), and the air purification unit (2) is connected with the LNG cold energy utilization unit through the second-stage cold storage medium loop (25). The air purification unit (2) comprises a spray tower (201) and a decarburization set (202), the spray tower (201) is connected with the air compressor set through the decarburization set (202), the spray tower (201) is connected with the second-stage cold storage medium loop (25), and the spray tower (201) is used for directly contacting air with second-stage cold storage medium to dehydrate and cool the air. The alcohol-water solution is used as the second-stage cold storage medium.

2. The air dehydration decarbonization purification system of claim 1, wherein, The decarburization set (202) comprises at least one of at least two switchable heat exchangers (221) and a molecular sieve purifier (206). The decarburization set (202) comprises at least two switchable heat exchangers (221), each group of the switchable heat exchangers (221) is connected in parallel between the spray tower (201) and the air compressor set, each switchable heat exchanger (221) is connected with the first-stage cold storage medium loop (24), and each first-stage cold storage medium loop (24) is connected in parallel with each other. The decarburization set (202) comprises a molecular sieve purifier (206), the air compressor set comprises a plurality of stages of air cryogenic compressors connected in sequence, the spray tower (201) is connected with an inlet end of a first-stage air cryogenic compressor (3), and the molecular sieve purifier (206) is connected between any two stages of the air cryogenic compressors.

3. The air dehydration decarbonization purification system of claim 2, wherein, The first-stage cold storage medium loop (24) comprises a first-stage cold storage medium cold tank (222) and a first-stage cold storage medium hot tank (223), a first-stage heat absorption pipeline and a first-stage heat release pipeline are respectively connected between the first-stage cold storage medium cold tank (222) and the first-stage cold storage medium hot tank (223), each switchable heat exchanger (221) is connected with the first-stage heat absorption pipeline, and the first-stage heat release pipeline is connected with an LNG vaporizer (22) of the LNG cold energy utilization unit.

4. The air dehydration decarbonization purification system of claim 2, wherein, The decarburization set (202) further comprises a heat pump air blowing and ice removing module, the heat pump air blowing and ice removing module is connected with each switchable heat exchanger (221), and the heat pump air blowing and ice removing module is used for blowing air into the switchable heat exchanger (221) to remove ice.

5. The air dehydration decarbonization purification system according to any one of claims 1-4, wherein, The secondary cold storage medium circuit (25) comprises a secondary cold storage medium cold tank (203) and a secondary cold storage medium hot tank (205), and a secondary heat absorption pipeline and a secondary heat release pipeline are connected between the secondary cold storage medium cold tank (203) and the secondary cold storage medium hot tank (205), respectively, the spray tower (201) is connected to the secondary heat absorption pipeline, and the secondary heat release pipeline is connected with a natural gas superheater (23) of the LNG cold energy utilization unit.

6. The air dehydration decarbonization purification system of claim 5, wherein, The air purification unit (2) further comprises a water solution concentration module (204) installed on the secondary heat absorption pipeline and connected between the spray tower (201) and the secondary cold storage medium hot tank (205).

7. The air dehydration decarbonization purification system according to any one of claims 1-4, wherein, The air purification unit (2) further comprises an air filter, and the spray tower (201) is connected to an air source through the air filter, and the air filter is used for pre-filtering air entering the spray tower (201).

8. The air dehydration decarbonization purification system of claim 7, wherein, The air purification unit (2) further comprises a water cooling tower connected between the air filter and the spray tower (201); and / or, The spray tower (201) is a multi-stage spray tower (201), and each stage of the spray tower (201) is connected in series between the air filter and the decarburization unit (202) through an air inlet pipeline (210); each stage of the spray tower (201) is connected to a secondary cold storage medium circuit (25), and a medium return pipeline (211) is connected between adjacent spray towers (201).

9. A liquid air energy storage power plant characterized in that, It comprises: An LNG cold energy utilization unit; The air dehydration and decarburization purification system according to any one of claims 1-8, connected to the LNG cold energy utilization unit; An energy storage module comprising a multi-stage compressor unit, an air heat release side of a cold box (8), a liquid expander (9), a throttle valve (10), a gas-liquid separator (11) and a liquid air storage tank (12) connected in sequence, an inlet end of the multi-stage compressor unit being connected to an air purification unit (2) of the air dehydration and decarburization purification system, the multi-stage compressor unit being connected to the LNG cold energy utilization unit; An energy release module comprising a multi-stage air expander unit, the liquid air storage tank (12) being connected to the multi-stage air expander unit through an air heat absorption side of the cold box (8).

10. A method of air dehydration decarbonation purification, characterized by, The air dehydration and decarburization purification method is performed by the air dehydration and decarburization purification system according to any one of claims 1-8, and comprises the following steps: The cold energy in the LNG cold energy utilization unit is sequentially absorbed by the cold storage medium in the at least two-stage cold storage medium circulation circuits; Air and secondary cold storage medium are both introduced into the spray tower (201) to directly contact the air with the secondary cold storage medium to dehydrate and cool the air, and the dehydrated air enters the decarburization unit (202) to realize decarburization; The decarburized air can be used to prepare compressed air, and the cold energy is transmitted to the preparation process of the compressed air by the primary cold storage medium.

Images