Control method of circulating water system of liquid air energy storage power station

Abstract

The present invention relates to the field of energy storage technology, and in particular to a control method for a circulating water system of a liquid air energy storage power station and a liquid air energy storage power station. The control method for the circulating water system of the liquid air energy storage power station includes: determining that the actual pressure in the second storage tank reaches a first set pressure, and controlling the gas in the second storage tank to be discharged into the first storage tank, wherein the first set pressure is the maximum operating pressure of the second storage tank. While the air in the second storage tank is emptied to meet the pressure requirement, the condensed water contained in the high-pressure breathing gas in the second storage tank is recovered in the first storage tank, reducing the waste of water resources, while ensuring the operating efficiency of the heat storage device, avoiding problems such as insufficient reheating of the high-pressure air and a decrease in power generation during the energy release stage, thereby improving the overall efficiency of the energy storage power station.

Description

Technical Field

[0001] The present invention relates to the field of energy storage technology, and in particular to a control method for a circulating water system of a liquid air energy storage power station and a liquid air energy storage power station. Background Art

[0002] In the liquid air energy storage system, whether the compression heat can be fully utilized determines the round-trip efficiency of the system. The heat storage unit is a technical key that directly affects the compression heat utilization effect, and its operating performance is directly related to the overall performance of the system. By adjusting the appropriate construction method and operation strategy of the heat storage unit, the round-trip efficiency of the liquid air energy storage power station can be improved, the economy of the energy storage device can be effectively improved, and the waste of water resources in dry and water-scarce areas can be avoided. It has a high environmental affinity and has extremely high social and economic benefits.

[0003] As an important component of the liquid air energy storage power station, the operating performance of the heat storage device directly affects the reheating performance and the operating efficiency of the turbine equipment during the energy release stage. When high-pressure hot water enters and leaves the hot water tank, it may be accompanied by phase change processes such as liquefaction and flash evaporation, which in turn has a significant impact on parameters such as the temperature and pressure inside the tank, causing problems such as insufficient reheating of high-pressure air and reduced power generation during the energy release stage, which in turn affects the overall efficiency of the energy storage system. Summary of the invention

[0004] The present invention provides a control method for the circulating water system of a liquid air energy storage power station and a liquid air energy storage power station, which are used to solve one of the defects in the prior art. At the same time, the air in the second storage tank is emptied to meet the pressure requirement, and the condensed water of the water vapor contained in the high-pressure breathing gas in the second storage tank is recovered in the first storage tank, thereby reducing the waste of water resources and ensuring the operating efficiency of the heat storage device. It avoids the problems of insufficient reheating of the high-pressure air and reduced power generation in the energy release stage, thereby improving the overall efficiency of the energy storage power station.

[0005] The present invention provides a control method for a circulating water system of a liquid air energy storage power station. The liquid air energy storage power station includes a circulating water system, an energy storage device and an energy release device. The circulating water system includes a first storage tank and a second storage tank. The first storage tank, a heat absorption path of the energy storage device, the second storage tank and a heat release path of the energy release device are sequentially connected to form a loop suitable for circulating water. The exhaust port of the second storage tank is connected to the air inlet of the first storage tank, including:

[0006] Determine that the actual pressure in the second storage tank reaches a first set pressure, and control the gas in the second storage tank to be discharged into the first storage tank, wherein the first set pressure is the maximum operating pressure of the second storage tank.

[0007] A control method for a circulating water system of a liquid air energy storage power station provided by the present invention further includes:

[0008] It is determined that the operating time of the energy release device reaches a set time, and the second storage tank is controlled to increase the temperature, wherein the set time is 3 / 5 to 2 / 3 of the total time of the energy release stage.

[0009] A control method for a circulating water system of a liquid air energy storage power station provided by the present invention further includes:

[0010] Determine that during the energy release stage, the actual stock of circulating water in the second storage tank reaches the set stock, and control the second storage tank to increase the temperature, wherein the set stock is 2 / 5 to 1 / 3 of the circulating water stock of the second storage tank after the energy storage stage.

[0011] According to a control method for a circulating water system of a liquid air energy storage power station provided by the present invention, controlling the temperature of the second storage tank to rise includes electrically heating the second storage tank, or increasing the circulating water inventory in the second storage tank.

[0012] A control method for a circulating water system of a liquid air energy storage power station provided by the present invention further includes:

[0013] When the energy storage device is turned on, increasing the actual pressure in the second storage tank;

[0014] Determine that the actual pressure in the second storage tank reaches a second set pressure, and control the heat absorption passage of the energy storage device to deliver circulating water to the second storage tank, wherein the second set pressure is the saturated steam pressure corresponding to the high-temperature circulating water.

[0015] According to a control method for a circulating water system of a liquid air energy storage power station provided by the present invention, the circulating water system further includes an air cooling device, the first storage tank, the heat release path of the air cooling device and the heat absorption path of the energy storage device are connected in sequence, and further includes:

[0016] Determine that the average temperature of the external environment is greater than the first set temperature and less than or equal to the second set temperature, and control the air cooling device to operate at the set power; or,

[0017] Determine that the average temperature of the external environment is greater than the second set temperature, and control the air cooling device to operate when the actual temperature of the external environment is less than the second set temperature; or,

[0018] Determine that the average temperature of the external environment is less than or equal to the first set temperature, and control the air cooling device to operate when the actual temperature of the external environment is greater than the first set temperature;

[0019] The first set temperature has a value range of 0 to 2°C, and the second set temperature has a value range of 18 to 20°C.

[0020] According to a control method for a circulating water system of a liquid air energy storage power station provided by the present invention, it is determined that the average temperature of the external environment is greater than the second set temperature, and the air cooling device is controlled to perform wet operation when the actual temperature of the external environment is less than the second set temperature.

[0021] According to a control method for a circulating water system of a liquid air energy storage power station provided by the present invention, it is determined that the average temperature of the external environment is less than or equal to the first set temperature, and the air cooling device is controlled to perform dry operation when the actual temperature of the external environment is greater than the first set temperature.

[0022] The present invention also provides a liquid air energy storage power station, which implements the control method of the circulating water system of the liquid air energy storage power station as described above, and the pipeline connecting the exhaust port of the second storage tank and the air inlet of the first storage tank is provided with a valve body.

[0023] According to a liquid air energy storage power station provided by the present invention, the first storage tank is provided with a cooling component suitable for condensing steam.

[0024] In the control method of the circulating water system of the liquid air energy storage power station of the embodiment of the present invention, in the energy storage stage, the circulating water in the first storage tank enters the heat absorption channel of the energy storage device to absorb the heat of the compressed air, and enters the second storage tank after the temperature is increased from low-temperature circulating water to high-temperature circulating water. After the energy storage device is initially started, the interior of the second storage tank, which is a high-temperature circulating water storage tank, is at normal temperature and pressure. In the process of the high-temperature and high-pressure circulating water entering the second storage tank, the pressure in the tank will continue to rise, and the actual pressure in the second storage tank is obtained by real-time detection. When the pressure of the second storage tank rises to the first set pressure, that is, the actual pressure reaches the maximum operating pressure designed for the second storage tank, the mixed gas of air and water vapor in the second storage tank is discharged to the first storage tank, which is a normal temperature circulating water storage tank, and the water vapor in the mixed gas is recovered in the first storage tank, and the air is directly discharged.

[0025] In this embodiment, based on the circulating water loop coordinated with the high-pressure heat storage loop, a control strategy for the second storage tank and the first storage tank during the initial startup and normal operation period is provided, so that the air in the second storage tank is emptied to meet the pressure requirement, and the condensed water contained in the high-pressure breathing gas in the second storage tank is recovered in the first storage tank, reducing the waste of water resources. At the same time, the operating efficiency of the heat storage device is ensured, avoiding problems such as insufficient reheating of high-pressure air and reduced power generation during the energy release stage, thereby improving the overall efficiency of the energy storage power station.

[0026] In addition to the technical problems solved by the present invention, the technical features of the technical solutions constituted, and the advantages brought about by the technical features of these technical solutions described above, other technical features of the present invention and the advantages brought about by these technical features will be further explained in conjunction with the accompanying drawings or will be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 This is one of the structural schematic diagrams of the liquid air energy storage power station provided by the present invention;

[0029] Figure 2 It is a schematic diagram of the pressure change of the second storage tank when the energy storage stage of the liquid air energy storage power station provided by the present invention is first started;

[0030] Figure 3 It is a schematic diagram of the pressure change of the second storage tank during normal operation of the liquid air energy storage power station provided by the present invention during the energy storage stage;

[0031] Figure 4 It is a schematic diagram of the pressure change of the second storage tank in the energy release stage of the liquid air energy storage power station provided by the present invention;

[0032] Figure 5 It is a schematic diagram of the water temperature change of the remaining circulating water in the second storage tank during the energy release stage of the liquid air energy storage power station provided by the present invention;

[0033] Figure 6 This is the second structural schematic diagram of the liquid air energy storage power station provided by the present invention

[0034] Figure 7 This is the third structural schematic diagram of the liquid air energy storage power station provided by the present invention.

[0035] Reference numerals:

[0036] 100, energy storage device; 110, air compressor; 120, cooling unit; 121, first cooler; 122, second cooler; 130, cooler; 140, preheater;

[0037] 200, first air cooler; 210, air cooling device; 220, valve body; 230, high temperature water pump; 240, normal temperature water pump;

[0038] 300, energy release device; 310, gas expander; 320, heater;

[0039] 400, second air cooler; 500, cold storage tank; 510, first storage tank; 600, hot storage tank; 610, second storage tank; 700, air purifier; 800, cold box; 900, air filter; 1000, circulating water system. DETAILED DESCRIPTION

[0040] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0041] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0042] 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.

[0043] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0044] In addition, in the description of the embodiments of the present invention, unless otherwise specified, "multiple", "multiple roots", and "multiple groups" mean two or more, and "several", "several roots", and "several groups" mean one or more.

[0045] 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.

[0046] like Figure 1 , Figure 6 and Figure 7 As shown, the control method of the circulating water system of the liquid air energy storage power station provided in the embodiment of the present invention is based on the circulating water control of the liquid air energy storage power station of this embodiment. The liquid air energy storage power station includes a cold box 800, a circulating water system 1000, an energy storage device 100 and an energy release device 300. The circulating water system 1000 includes a first storage tank 510, a second storage tank 610 and an air cooling device 210. The first storage tank 510, the heat release path of the air cooling device 210, the heat absorption path of the energy storage device 100, the heat release path of the energy release device 300 and the second storage tank 610 are connected in sequence to form a loop suitable for circulating water circulation; the exhaust port of the second storage tank 610 is connected to the air inlet of the first storage tank 510; a valve body 220 is provided on the pipeline connecting the exhaust port of the second storage tank 610 and the air inlet of the first storage tank 510.

[0047] The air cooling device 210 includes multiple air coolers, and the energy storage device 100 includes a preheater 140, an air compressor 110 and a cooler 130. The heat absorption channel of the preheater 140 and the heat release channel of the air compressor 110 and the cooler 130 are connected in sequence, and the first storage tank 510 is connected to the heat release channel of the preheater 140.

[0048] The liquid air energy storage power station of the embodiment of the present invention is mainly composed of an energy storage device 100, a circulating water system 1000, an energy release device 300 and a cold box 800. Liquid air energy storage is a normal pressure low temperature liquid energy storage. The energy storage device 100 is composed of an air compressor unit, an air compressor unit stage aftercooler group and connecting pipelines; the circulating water system 1000 is composed of a second storage tank 610 as a high temperature circulating water heat storage spherical tank, a water vapor recovery pipeline with a breathing valve, a first storage tank 510 as a medium temperature circulating water storage tank, a normal temperature water pump 240, a high temperature water pump 230, an air cooling device 210 composed of multiple air coolers and connecting pipelines; the energy release device 300 is composed of a gas expansion unit, a heater before the expansion machine stage and connecting pipelines.

[0049] For the air side, in the energy storage stage, air at normal temperature and pressure enters the air compressor 110 and is pressurized to a specified pressure of about 7MPa. Then, the high-pressure air enters the air cooler, releases heat, and enters the cold box 800 in the form of compressed air at normal temperature and high pressure. After multi-stage cooling and expansion throttling, the air is stored in the form of liquid air at low temperature and normal pressure. In the energy release stage, the liquid air is pressurized and reheated in the cold box 800, and becomes air at normal temperature and high pressure. It enters the heater 320, absorbs the compression heat stored by the circulating water system 1000, and then enters the gas expander 310 to expand and generate electricity, and finally is discharged at normal pressure to complete the energy release and power generation process.

[0050] For the circulating water side, in the energy storage stage, the medium-temperature hot water, about 80°C, is pumped out from the first storage tank 510 by the medium-temperature water pump, enters the air cooler for rapid cooling, and then absorbs heat through the cooler 130, and enters the second storage tank 610 in the form of high-temperature and high-pressure hot water. In the energy release stage, the high-temperature and high-pressure hot water is pumped out from the second storage tank 610 by the high-temperature water pump 230, releases heat through the heater 320, and returns to the first storage tank 510 in the form of medium-temperature and normal-pressure water, about 80°C after cooling, completing the closed cooling water heat storage cycle.

[0051] In one embodiment, the number of air compressors 110 and coolers 130 is not fixed. In practice, multi-stage air compressors 110 and multi-stage coolers 130 should be alternately connected in series, and the number of series stages is determined according to the designed compressed air energy storage pressure. The air compressor 110 can be a piston type, screw type or centrifugal type structure, and the final exhaust pressure range of the air compressor 110 can be 5MPa to 10MPa; the cooler 130 can be a plate heat exchanger or a shell and tube heat exchanger in the low-pressure section, and a shell and tube heat exchanger in the high-pressure section.

[0052] In one embodiment, the number of gas expanders 310 and heaters 320 is not fixed, and should actually be composed of multiple stages of gas expanders 310 and multiple stages of heaters 320 alternately connected in series, and the number of series stages is determined according to the designed compressed air pressure. The heater 320 can be one or a combination of shell and tube structure, plate-fin structure, winding tube structure, etc.; the gas expander 310 can be a radial flow type, axial flow type, or radial-axial flow type.

[0053] In one embodiment, the second storage tank 610 may be a steel welded spherical storage tank. The high temperature water pump 230 and the normal temperature water pump 240 may be piston type or centrifugal type. The air cooler in dry areas may be a blast type dry air cooling tower with multiple fans, the tube bundle is placed horizontally, and each air cooler may be arranged in parallel or in series.

[0054] The control method of the circulating water system 1000 of the liquid air energy storage power station provided in the embodiment of the present invention includes:

[0055] It is determined that the actual pressure in the second storage tank 610 reaches the first set pressure, and the gas in the second storage tank 610 is controlled to be discharged into the first storage tank 510, wherein the first set pressure is the maximum operating pressure of the second storage tank 610.

[0056] According to the control method of the circulating water system 1000 of the liquid air energy storage power station of the embodiment of the present invention, in the energy storage stage, the circulating water in the first storage tank 510 enters the heat absorption channel of the energy storage device 100 to absorb the heat of the compressed air, and enters the second storage tank 610 after the temperature is increased from low-temperature circulating water to high-temperature circulating water. After the energy storage device 100 is initially started, the interior of the second storage tank 610, which is a high-temperature circulating water storage tank, is at normal temperature and pressure. In the process of high-temperature and high-pressure circulating water entering the second storage tank 610, the pressure in the tank will continue to rise. The actual pressure in the second storage tank 610 is detected and obtained in real time. When the pressure of the second storage tank 610 rises to the first set pressure, that is, the actual pressure reaches the designed maximum operating pressure of the second storage tank 610, the mixed gas of air and water vapor in the second storage tank 610 is discharged to the first storage tank 510, which is a normal temperature circulating water storage tank. The water vapor in the mixed gas is recovered in the first storage tank 510, and the air is directly discharged.

[0057] In this embodiment, based on the circulating water loop coordinated with the high-pressure heat storage loop, a control strategy for the second storage tank 610 and the first storage tank 510 is provided during the initial startup and normal operation period, so that the air in the second storage tank 610 is emptied to meet the pressure requirement, and the condensed water contained in the high-pressure breathing gas in the second storage tank 610 is recovered in the first storage tank 510, thereby reducing the waste of water resources. At the same time, the operating efficiency of the heat storage device is ensured, and the problems such as insufficient reheating of high-pressure air and reduced power generation during the energy release stage are avoided, thereby improving the overall efficiency of the energy storage power station.

[0058] According to one embodiment of the present invention, the control method of the circulating water system of the liquid air energy storage power station further includes:

[0059] It is determined that the operating time of the energy release device 300 reaches the set time, and the second storage tank 610 is controlled to increase the temperature, wherein the set time is 3 / 5 to 2 / 3 of the total time of the energy release stage.

[0060] In the energy release stage, the normal temperature and high pressure air on the air side enters the heat exchanger from the cold box 800 to absorb heat, then enters the gas expander 310 to expand and generate electricity, and finally is discharged at normal pressure to complete the energy release and power generation. On the circulating water side, the high temperature and high pressure circulating water is pumped out from the second storage tank 610 by the high temperature water pump 230, releases heat through the heat exchanger, and enters the first storage tank 510 in the form of normal temperature and pressure water after cooling. In this process, the first startup and normal operation are not distinguished.

[0061] When the high-temperature circulating water leaves the second storage tank 610, the volume of the gas phase space in the second storage tank 610 increases and the pressure decreases. When the pressure in the second storage tank 610 drops to the saturated vapor pressure corresponding to the temperature of the high-temperature circulating water, the remaining high-temperature circulating water in the second storage tank 610 begins to partially flash evaporate to resist the pressure reduction trend. At the same time, the flash evaporation process absorbs heat, causing the temperature of the remaining high-temperature circulating water in the second storage tank 610 to slightly decrease. The decrease is more obvious when there is less high-temperature circulating water remaining in the second storage tank 610.

[0062] The pressure variation trend in the second storage tank 610 is as follows Figure 4 As shown, since the volume flow rate of the stream out of the second storage tank 610 is fixed, the rate of increase of the volume of the top gas phase space is also constant. In the first period of the energy release stage, since the initial gas phase space volume is small, the pressure reduction factor caused by the increase in the gas phase space volume per unit time accounts for a large proportion, and as the gas phase space volume increases, the influence gradually decreases, which is reflected in the trend diagram as the slope of the curve gradually becomes flat. After the middle time period of the energy release stage, because the amount of circulating water remaining in the second storage tank 610 gradually decreases, the temperature drop caused by flash evaporation is gradually reflected in the temperature change of the remaining water. Because the saturated vapor pressure decreases due to the temperature decrease, the water vapor partial pressure in the top gas phase space gradually decreases, which is comprehensively manifested as the gradual increase in the pressure reduction amplitude of the top gas phase space, which is reflected in the trend diagram as the gradual increase in the slope of the curve.

[0063] The temperature variation trend in the second storage tank 610 is as follows Figure 5 As shown, in the initial period of the energy release stage, the amount of remaining circulating water is large, and the temperature drop caused by flash evaporation is small. As the amount of remaining circulating water decreases, the temperature drop caused by flash evaporation endothermic absorption gradually increases, which is reflected in the change trend diagram as the slope of the curve gradually increases.

[0064] In order to ensure the energy release efficiency and ensure that the high-pressure air has sufficient heat when it is reheated through the heat exchanger during the energy release stage, and to reduce the impact of flash evaporation heat absorption on the high-temperature circulating water, the temperature of the second storage tank 610 can be increased in the last 1 / 3 to 2 / 5 time period of the energy release stage, that is, the remaining circulating water in the second storage tank 610 is heated and heated, thereby ensuring that the temperature of the circulating water in the second storage tank 610 drops less after flash evaporation, and the impact on other equipment in the energy release stage is as small as possible.

[0065] In this embodiment, the operating time of the energy release device 300 is detected in real time. When the operating time of the energy release device 300 reaches 3 / 5 to 2 / 3 of the total duration of the energy release stage, that is, the remaining duration of the energy release stage is 1 / 3 to 2 / 5, the second storage tank 610 is controlled to heat up, and the set duration can be 2 / 3 of the total duration of the energy release stage.

[0066] In the energy release stage, this embodiment analyzes the changing trends of temperature and pressure in the process of discharging high-temperature circulating water from the second storage tank 610, including flash evaporation, to solve the problem of insufficient reheating in the energy release process due to the decrease in circulating water temperature, to avoid the decrease in circulating water temperature as much as possible, and to propose corresponding adjustment measures, so as to achieve the goal that the temperature of the high-temperature and high-pressure circulating water flowing out of the second storage tank 610 in the energy release stage does not decrease almost, and the impact on other equipment in the energy release stage is minimized, thereby maintaining the round-trip efficiency of the system at a high level at all times.

[0067] According to one embodiment of the present invention, the control method of the circulating water system of the liquid air energy storage power station further includes:

[0068] Determine that during the energy release phase, the actual stock of circulating water in the second storage tank 610 reaches the set stock, and control the second storage tank 610 to increase the temperature, wherein the set stock is 1 / 3 to 2 / 5 of the circulating water stock of the second storage tank 610 after the energy storage phase.

[0069] To ensure the energy release efficiency and ensure that the high-pressure air has sufficient heat when it is reheated through the heat exchanger during the energy release stage, and to reduce the impact of flash evaporation heat absorption on the high-temperature circulating water, the temperature of the second storage tank 610 can be increased when the amount of high-temperature circulating water discharged from the second storage tank 610 during the energy release stage only accounts for 2 / 3 of the total amount of water stored in the second storage tank 610. This ensures that the temperature of the circulating water in the second storage tank 610 drops less after flash evaporation, and the impact on other equipment during the energy release stage is as small as possible.

[0070] In this embodiment, the circulating water inventory in the second storage tank 610 is detected in real time. When the actual inventory of the circulating water in the second storage tank 610 reaches 1 / 3 to 2 / 5 of the circulating water inventory of the second storage tank 610 after the energy storage stage, that is, the actual inventory of the circulating water is 1 / 3 to 2 / 5 of the total amount, the second storage tank 610 is controlled to increase the temperature, and the set inventory can be 1 / 3 of the total amount.

[0071] According to one embodiment of the present invention, controlling the temperature of the second storage tank 610 includes electrically heating the second storage tank 610, or increasing the amount of circulating water in the second storage tank 610. In this embodiment, the heating of the second storage tank 610 can be achieved by electrically heating the second storage tank 610, or by conveying high-temperature circulating water into the second storage tank 610 to increase the amount of circulating water.

[0072] According to one embodiment of the present invention, the control method of the circulating water system of the liquid air energy storage power station further includes:

[0073] When the energy storage device 100 is turned on, the actual pressure in the second storage tank 610 is increased;

[0074] Determine that the actual pressure in the second storage tank 610 reaches the second set pressure, and control the heat absorption passage of the energy storage device 100 to deliver circulating water to the second storage tank 610, wherein the second set pressure is the saturated steam pressure corresponding to the high-temperature circulating water.

[0075] In this embodiment, when the energy storage device 100 is started for the first time, the interior of the second storage tank 610 is at normal temperature and pressure. In the process of high-temperature and high-pressure circulating water entering the second storage tank 610, it will enter in the form of steam during the initial period of the energy storage stage, causing the pressure in the second storage tank 610 to continue to rise. When the pressure in the second storage tank 610 meets the saturated vapor pressure corresponding to the temperature of the high-temperature and high-pressure circulating water, the circulating water begins to enter the second storage tank 610 in the form of high-temperature and high-pressure liquid water. After the circulating water enters the second storage tank 610, the pressure in the second storage tank 610 will continue to rise. When the pressure in the second storage tank 610 rises to the maximum operating pressure designed for the second storage tank 610, the valve body 220 is opened to discharge the mixed gas of air and water vapor in the second storage tank 610 into the first storage tank 510, and the water vapor in the mixed gas is condensed and recovered, and the air is directly discharged.

[0076] According to one embodiment of the present invention, a condensation component is provided in the first storage tank 510. In this embodiment, the condensation component can be provided at the bottom of the first storage tank 510, and the normal temperature circulating water entering the first storage tank 510 can be cooled in the form of a coil, the water vapor in the mixed gas is condensed and recovered, and the air is directly discharged.

[0077] The present invention proposes two different control strategies for the operation of the second storage tank 610 in the energy storage stage under the two conditions of the first startup and normal operation of the high-temperature and high-pressure energy storage device 100, and proposes a solution to pass the high-temperature external water vapor into the first storage tank 510 during the first startup process, condense it in the first storage tank 510, and recover the condensed water. The energy storage device 100 of the liquid-air energy storage system solves the problem that when the high-pressure and high-temperature circulating water enters and exits the second storage tank 610, its phase state will change, and the temperature and pressure changes caused by liquefaction and flash evaporation will cause insufficient reheating of the high-pressure air in the energy release stage, a decrease in power generation, and other problems, thereby improving the overall efficiency of the energy storage power station.

[0078] During this process, the pressure variation trend inside the second storage tank 610 is as follows: Figure 2 As shown. The first inflection point of the solid line segment represents that the pressure in the second storage tank 610 reaches the saturated steam pressure corresponding to the hot water temperature. After this point, the incoming stream is high-temperature and high-pressure circulating water, and before this point, it is high-pressure steam; the second inflection point represents that the pressure in the second storage tank 610 reaches the maximum operating pressure set for the second storage tank 610, and the breathing valve is opened. After this point, the pressure in the second storage tank 610 maintains a constant value. The dotted line segment represents the change trend of the pressure in the second storage tank 610 if the breathing valve is not opened and the upper limit of the pressure of the second storage tank 610 is not limited.

[0079] In particular, when the unit operates normally, the pressure change trend in the second storage tank 610 is similar to the above process. The main difference is that the initial pressure at the first startup is normal pressure, while the initial pressure during normal operation is the pressure in the tank at the end of the previous energy release stage. The changes in the tank pressure during the energy release process are described in detail later.

[0080] During this process, the pressure variation trend inside the second storage tank 610 is as follows: Figure 3 As shown. The first inflection point of the solid line segment represents that the pressure in the second storage tank 610 reaches the saturated steam pressure corresponding to the hot water temperature. After this point, the incoming stream is high-temperature and high-pressure circulating water, and before this point, it is high-pressure steam. There is no overpressure in this process, so there is no need to open the breathing valve for external discharge.

[0081] According to one embodiment of the present invention, the circulating water system 1000 further includes an air cooling device 210, the first storage tank 510, the heat release path of the air cooling device 210 and the heat absorption path of the energy storage device 100 are sequentially connected, and the control method of the circulating water system of the liquid air energy storage power station further includes:

[0082] Determine that the average temperature of the external environment is greater than the first set temperature and less than or equal to the second set temperature, and control the air cooling device 210 to operate at the set power; or,

[0083] Determine that the average temperature of the external environment is greater than the second set temperature, and control the air cooling device 210 to operate when the actual temperature of the external environment is less than the second set temperature; or,

[0084] Determine that the average temperature of the external environment is less than or equal to the first set temperature, and control the air cooling device 210 to operate when the actual temperature of the external environment is greater than the first set temperature;

[0085] The first set temperature has a value range of 0 to 2°C, and the second set temperature has a value range of 18 to 20°C.

[0086] The control method of the circulating water system of the liquid air energy storage power station of the embodiment of the present invention is a control method of the circulating water system 1000 of the liquid air energy storage power station in arid climate areas. In arid climate areas, there is usually insufficient water supply, and the use of open water cooling is prone to waste of water resources and many other problems, while the use of air cooling alone cannot meet the large-scale heat storage needs. Therefore, when large-scale liquid air energy storage is carried out in such areas, the setting and control method of the circulating water system 1000 should be specially set and planned.

[0087] The embodiment of the present invention is aimed at liquid air energy storage power stations in dry climate areas, uses a combined heat storage method of closed cooling water circulation + air cooling, and proposes corresponding control and adjustment methods under different environmental temperature, humidity and other conditions in different seasons.

[0088] In this embodiment, an air cooler is arranged between the first storage tank 510 and the cooler 130, which is greatly affected by the ambient temperature. When the value range of the first set temperature is 0-2°C and the value range of the second set temperature is 18-20°C, when the average temperature of the external environment is greater than the first set temperature and less than or equal to the second set temperature, that is, in spring and autumn, the air cooler is turned on and operated at the set power; when the average temperature of the external environment is greater than the second set temperature, that is, in a relatively high temperature condition or in summer, the air cooler should be controlled to operate when the actual temperature of the external environment is less than the second set temperature, that is, the air cooler is air-cooled at night and not during the day, and it is avoided to turn on the air cooler during the day or at a relatively high temperature, which will cause a relatively adverse effect on the compression heat recovery of the energy storage device 100 and the operation of the cold box 800; when the average temperature of the external environment is less than or equal to the first set temperature, that is, in a relatively low temperature condition or in winter, the air cooler should be controlled to operate when the actual temperature of the external environment is greater than the first set temperature, that is, the air cooler is air-cooled during the day and not at night.

[0089] The circulating water system 1000 of this embodiment is a combination of closed water cooling and air cooling, wherein the temperature variation range of the closed water cooling of the cooler 130 is from medium temperature to high temperature, about 80°C to 200°C, and is cooled to room temperature, about 30°C, after being air-cooled by the air cooler. In dry areas, an air cooling device 210 is used as an air-cooled combined cooler 130, and the operating time period of the air cooling device 210 is adjusted according to seasonal temperature changes, thereby avoiding the waste of water resources caused by open water cooling in dry areas, having a high environmental affinity, and ensuring a high system round-trip efficiency. Combining the system requirements with the temperature changes caused by the changing seasons, a control method for the air cooling device 210 in the circulating water system 1000 under different seasonal conditions is specifically proposed, which can reduce the reduction in system round-trip efficiency caused by changes in natural conditions such as ambient temperature while basically meeting the heat storage requirements.

[0090] It is understandable that the first set temperature and the second set temperature can be accurate temperature values ​​or range values ​​within a certain interval. In this embodiment, the first set temperature is 0°C and the second set temperature is 18°C.

[0091] According to an embodiment provided by the present invention, it is determined that the average temperature of the external environment is greater than the second set temperature, and multiple air coolers are controlled to operate when the actual temperature of the external environment is less than the second set temperature. In this embodiment, the air cooling device 210 is a plurality of air coolers. When the average temperature of the external environment is greater than the second set temperature, that is, in a high temperature condition or in summer, the air coolers should be controlled to operate when the actual temperature of the external environment is less than the second set temperature, that is, the air coolers are air-cooled at night and not during the day, and the number of air coolers in operation is appropriately increased to ensure that the cooling efficiency and cooling temperature of the air coolers are not affected by the high temperature of the outside world.

[0092] In dry areas, the air cooling device 210 is used as the air cooling combined with the cooler 130, and the number of air coolers in operation is adjusted according to seasonal temperature changes, thereby avoiding the waste of water resources caused by open water cooling in dry areas, having a high environmental affinity, and ensuring a high system round-trip efficiency. Combining the system requirements with the temperature changes caused by the seasons, a control method for the air cooling device 210 in the circulating water system 1000 under different seasonal conditions is specifically proposed, which can reduce the reduction in system round-trip efficiency caused by changes in natural conditions such as ambient temperature while basically meeting the heat storage requirements.

[0093] According to an embodiment provided by the present invention, it is determined that the average temperature of the external environment is greater than the second set temperature, and the air cooler is controlled to perform wet operation when the actual temperature of the external environment is less than the second set temperature. In this embodiment, the air cooling device 210 is a plurality of air coolers. When the average temperature of the external environment is greater than the second set temperature, that is, in a high temperature condition or in summer, the air cooler should be controlled to operate when the actual temperature of the external environment is less than the second set temperature, that is, the air cooler performs air cooling at night and does not perform air cooling during the day, and the number of air coolers in operation is appropriately increased. The water spraying facilities of the air cooler can be turned on to switch the air cooler to wet operation. In a dry environment, when the average temperature of the external environment is high, water spraying can increase the cooling capacity of air cooling, thereby improving the working efficiency of the air cooler.

[0094] According to an embodiment provided by the present invention, it is determined that the average temperature of the external environment is less than or equal to the first set temperature, and the air cooler is controlled to perform dry operation when the actual temperature of the external environment is greater than the first set temperature. In this embodiment, when the average temperature of the external environment is less than or equal to the first set temperature, that is, in a relatively low temperature condition or in winter, the air cooler should be controlled to operate when the actual temperature of the external environment is greater than the first set temperature, that is, the air cooler performs air cooling during the day and not at night, and the water spraying facilities of the air cooler can be turned off to switch the air cooler to dry operation. When the average temperature of the external environment is relatively low, water spraying will cause air cooling to absorb heat in advance, and air cooling will lose cooling capacity, which is not conducive to the cooling efficiency of the air cooler.

[0095] According to an embodiment provided by the present invention, it is determined that the average temperature of the external environment is less than the third set temperature, and the number of operating air coolers is reduced; wherein the third set temperature is less than the first set temperature. In this embodiment, when the average temperature of the external environment is less than or equal to the first set temperature, that is, in a relatively low temperature condition or in winter, the air cooler should be controlled to operate when the actual temperature of the external environment is greater than the first set temperature, that is, the air cooler is air-cooled during the day and not at night, and the water spraying facilities of the air cooler can be turned off to convert the air cooler to dry operation. When the temperature is further reduced, that is, when the average temperature of the external environment is less than the third set temperature, some air coolers can be turned off and the high-temperature circulating water can be cooled by natural ventilation. When the average temperature of the external environment is relatively low, the low temperature of the outside world and natural wind are used to cool the circulating water, saving water and reducing energy consumption.

[0096] In one embodiment, for the circulating water system 1000 operating in a dry area, the water spraying facilities in the aforementioned air cooler will not be available. Under the corresponding season and climate conditions, the number of fans should be increased or decreased accordingly to reduce the temperature variation of the circulating cooling water caused by the ambient temperature change.

[0097] According to an embodiment provided by the present invention, it is determined that the pressure in the second storage tank 610 is greater than the set pressure, and the gas in the second storage tank 610 is controlled to be discharged into the first storage tank 510. In this embodiment, the liquid air energy storage power station also includes a second storage tank 610, and the first storage tank 510, the heat release path of the air cooling device 210, the heat absorption path of the energy storage device 100, the second storage tank 610, and the heat absorption path of the energy release device 300 are sequentially connected to form a loop suitable for circulating water circulation, and the exhaust port of the second storage tank 610 is connected to the air inlet of the first storage tank 510.

[0098] At the initial start-up stage of the circulating water system 1000, in order to empty the air, water vapor, nitrogen, etc. in the second storage tank 610 and make the high-temperature circulating water entering the second storage tank 610 reach the required temperature, that is, to discharge the circulating water that does not reach the required temperature, the top air inlet of the first storage tank 510 is connected with the top exhaust port of the second storage tank 610, so that the circulating water flows into the first storage tank 510 and is stored as medium-temperature circulating water. During the operation of the circulating water system 1000, the temperature in the second storage tank 610 is relatively high, which is prone to pressure increase. In order to ensure the pressure safety of the second storage tank 610, the gas in the second storage tank 610 can also be discharged into the first storage tank 510. At this time, the gas discharged is a mixture of air and water vapor, thereby realizing closed water cooling of the entire circulating water system 1000 and avoiding waste of water resources.

[0099] According to an embodiment provided by the present invention, a valve body 220 is provided on the pipeline connecting the exhaust port of the second storage tank 610 and the air inlet of the first storage tank 510. In this embodiment, the valve body 220 controls the on-off of the pipeline, and can also control the opening and closing size of the pipeline, thereby controlling the gas or liquid flow, and preventing the water vapor in the first storage tank 510 from flowing back to the second storage tank 610.

[0100] According to an embodiment provided by the present invention, it is determined that the actual outside temperature is less than the first set temperature, and the first storage tank 510 is controlled to deliver circulating water to the preheater 140. In this embodiment, the energy storage device 100 includes the preheater 140, the air compressor 110 and the cooler 130, the heat absorption channel of the preheater 140, the heat release channel of the air compressor 110 and the cooler 130 are connected in sequence, and the first storage tank 510 is connected to the heat release channel of the preheater 140.

[0101] When the actual outside temperature is low, in order to reduce the consumption of the air compressor 110, the outside low-temperature and normal-pressure air is first preheated by the preheater 140. After a certain heating and temperature increase, it enters the air compressor 110 for compression and temperature increase. Therefore, the preheater 140 is added in front of the air compressor 110. The circulating water in the first storage tank 510 can flow through the heat release passage of the preheater 140 and exchange heat with the outside air in the heat absorption passage of the preheater 140. Since the first storage tank 510 is located in front of the air cooler, the circulating water in the first storage tank 510 is of medium temperature and can heat and heat the outside low-temperature air. The circulating water flowing out of the preheater 140 can choose a destination according to its temperature. It can flow back to the first storage tank 510 or flow into the air cooler. While saving water resources, it can also save energy consumption.

[0102] According to one embodiment of the present invention, the energy storage device 100 further includes an air purifier 700, which is disposed between the cooler 130 and the air compressor 110 before the air is discharged from the energy storage device 100. In this embodiment, in order to ensure the purity of the compressed air and prevent the air from containing impurities that may cause ice formation in the cold box 800, the air is first filtered and separated by the air purifier 700 before being discharged from the last cooler 130.

[0103] like Figure 7 As shown, the liquid air energy storage power station provided in an embodiment of the present invention includes an energy storage device 100 and a first air cooler 200. The energy storage device 100 includes an air compressor 110 and a cooling unit 120. The cooling unit 120 includes a first cooler 121 and a second cooler 122. The outlet of the air compressor 110, the heat release path of the first cooler 121, and the heat release path of the second cooler 122 are connected in sequence. The heat absorption path of the first cooler 121 is connected to the heat release path of the first air cooler 200 to form a first cooling circuit, and the heat absorption path of the second cooler 122 is suitable for forming a second cooling circuit.

[0104] In the liquid air energy storage power station of the embodiment of the present invention, during the energy storage process, outside air enters the air compressor 110, and the outlet temperature of the compressed air at the air compressor 110 is about 220°C, that is, the high-temperature and low-pressure air enters the first cooler 121 of the cooling unit 120 from the air compressor 110, and the compressed air entering the heat release path of the first cooler 121 exchanges heat with the first cooling medium in the heat absorption path of the first cooler 121. The first cooling medium circulates in the first cooling circuit and is cooled to 60°C by the first air cooler 200 before entering the first cooler 121, that is, the inlet temperature of the first cooling medium in the heat absorption path of the first cooler 121 is 60°C. After heat exchange with the compressed air, the outlet temperature of the first cooling medium in the heat absorption path of the first cooler 121 is about 195°C. At this time, the outlet temperature of the air in the heat release path of the first cooler 121 is about 89°C, and then enters the second cooler 122 for further cooling. The compressed air entering the heat release path of the second cooler 122 exchanges heat with the second cooling medium in the heat absorption path of the second cooler 122. The second cooling medium circulates in the second cooling circuit and is cooled to 25°C before entering the second cooler 122. That is, the inlet temperature of the second cooling medium in the heat absorption path of the second cooler 122 is 25°C. After exchanging heat with the compressed air, the outlet temperature of the second cooling medium in the heat absorption path of the second cooler 122 is about 55°C. At this time, the outlet temperature of the air in the heat release path of the second cooler 122 is about 38°C.

[0105] After the air passes through the air compressor 110 and the cooling unit 120 in sequence, it becomes high-pressure normal temperature air and is sent out to the second cooler 122. The first cooler 121 is used as the first-stage heat exchanger after the air compressor 110. The recovered compression heat is stored in the first cooling medium to ensure that the first cooling medium is 195°C for the energy release process. The first cooling medium can pass through the first air cooler 200 to 60°C in the first cooling circuit, and then enter the heat absorption path of the first cooler 121 again to realize the cooling cycle. The second cooler 122 is used as the second-stage heat exchanger after the air compressor 110, and performs secondary cooling on the compressed air after the first-stage heat exchange to meet the requirement of reducing the air temperature to 38°C. After the second cooling medium is cooled from 55°C to 25°C in the second cooling circuit, it enters the heat absorption path of the second cooler 122 again to realize the cooling cycle.

[0106] The present invention changes the setting mode of the cooling unit 120 after the air compressor 110 of the existing liquid air energy storage technology, that is, the cooling unit 120 adopts a two-stage heat exchanger, wherein the compressed air flows in series in the two-stage heat exchanger, and the cooling medium flows in parallel in the two-stage heat exchanger, so that the first cooling medium and the second cooling medium form two independent circulating cooling circuits, and the cooling medium in the first cooler 121 and the second cooler 122 has different temperatures at the inlet and outlet. The purpose is to reduce the temperature of the first cooling medium flowing out of the outlet of the first air cooler 200 by increasing the heat exchange area of ​​the first air cooler 200, even if the temperature of the first cooling medium entering the inlet of the heat absorption path of the first cooler 121 is reduced, thereby increasing the cold end temperature difference of the cooling unit 120, and increase the flow rate of the second cooling medium at the outlet of the heat absorption path of the second cooler 122 by increasing the flow rate of the second cooling circuit, even if the temperature of the second cooling medium flowing out of the outlet of the heat absorption path of the second cooler 122 is reduced, thereby increasing the hot end temperature difference of the cooling unit 120.

[0107] In this way, the average logarithmic temperature difference of the cooling medium on both sides of the cooling unit 120 can be increased, thereby reducing the heat exchange area of ​​each cooler, especially significantly reducing the heat exchange area of ​​the coolers on the medium and low pressure sides, making the cooling unit 120 simpler to manufacture and reducing the cost of the cooling unit 120. In addition, since the inlet temperature of the first cooling medium in the heat absorption path of the first cooler 121 is reduced, while the outlet temperature of the heat absorption path of the first cooler 121 remains unchanged, the temperature rise degree and heat exchange efficiency of the first cooling medium are improved, and the flow rate of the first cooling medium can be reduced under the same heat load. The purpose of adjusting the cooler end difference is achieved without affecting the recovery of the high-temperature heat source.

[0108] In one embodiment, the cooling unit 120 includes not only the first cooler 121 and the second cooler 122, but also a plurality of heat exchangers may be arranged between the first cooler 121 and the second cooler 122 according to actual compression heat recovery requirements.

[0109] According to an embodiment provided by the present invention, the liquid air energy storage power station also includes an energy release device 300, which includes a gas expander 310 and a heater 320. The heat absorption path of the heater 320 is connected to the inlet of the gas expander 310, and the heat absorption path of the first cooler 121, the heat release path of the heater 320 and the heat release path of the first air cooler 200 are connected in sequence to form a first cooling circuit.

[0110] In this embodiment, the heater 320 is used as a preheater before the air enters the gas expander 310. During the energy release process, the high-pressure normal temperature air first enters the heat absorption path of the heater 320 to exchange heat with the first cooling medium of the heat release path of the heater 320. The first cooling medium circulates in the first cooling circuit, flows out of the first cooler 121, and enters the heat release path of the heater 320 at 195°C, preheating the air in the heat absorption path of the heater 320. The first cooling medium cools down and enters the first air cooler 200 to cool to 60°C. In the next energy storage process, the compressed air in the first cooler 121 is cooled again. The high-pressure air then enters the gas expander 310 from the heater 320, expands and works in the gas expander 310, and becomes low-pressure air and is discharged.

[0111] According to an embodiment of the present invention, the heat absorption path of the second cooler 122 is connected to the heat release path of the first air cooler 200 to form a second cooling circuit. In this embodiment, during the energy storage process and the energy release process, the energy storage device 100 and the energy release device 300 share an air cooler.

[0112] During the energy storage process, the heat release path of the first air cooler 200 is connected to the heat absorption path of the second cooler 122 to form a second cooling circuit. The second cooling medium is cooled to 25°C in the first air cooler 200 and then enters the second cooler 122. After heat exchange with the compressed air, it is heated to 55°C and then returns to the first air cooler 200, thereby realizing a cooling cycle.

[0113] During the energy release process, the heat release path of the first air cooler 200 is connected to the heat absorption path of the first cooler 121 and the heat release path of the heater 320 to form a first cooling circuit. The first cooling medium is heated to 195°C in the first cooler 121 and then enters the heater 320, cools down after heat exchange with the compressed air, and then enters the first air cooler 200 to cool to 60°C. In the next energy storage process, the compressed air in the first cooler 121 is cooled again to realize the cooling cycle.

[0114] According to an embodiment provided by the present invention, the liquid air energy storage power station further includes a second air cooler 400, and the heat absorption path of the second cooler 122 is connected to the heat release path of the second air cooler 400 to form a second cooling circuit. In this embodiment, during the energy storage process and the energy release process, the energy storage device 100 and the energy release device 300 use two air coolers respectively, that is, the second air cooler 400 is always connected to the second cooler 122, and the first air cooler 200 is always connected to the first cooler 121, and there is no need to switch between the energy storage process and the energy release process.

[0115] During the energy storage process, the heat release path of the second air cooler 400 is connected with the heat absorption path of the second cooler 122 to form a second cooling circuit. The second cooling medium is cooled to 25°C in the second air cooler 400 and then enters the second cooler 122. After heat exchange with the compressed air, the temperature is raised to 55°C and then returns to the first air cooler 200, thereby realizing a cooling cycle.

[0116] During the energy release process, the heat release path of the first air cooler 200, the heat absorption path of the first cooler 121 and the heat release path of the heater 320 are connected in sequence to form a first cooling circuit. The first cooling medium is heated to 195°C in the first cooler 121 and then enters the heater 320, cools down after heat exchange with the compressed air, and then enters the first air cooler 200 to cool to 60°C. In the next energy storage process, the compressed air in the first cooler 121 is cooled again to realize the cooling cycle.

[0117] According to an embodiment provided by the present invention, the liquid air energy storage power station further includes a cold storage tank 500, the inlet of the cold storage tank 500 is connected to the outlet of the heat release path of the first air cooler 200, and the outlet of the cold storage tank 500 is connected to the inlet of the heat absorption path of the first cooler 121. In this embodiment, since the energy storage process of the energy storage device 100 and the energy release process of the energy release device 300 are performed independently, the cold storage tank 500 is additionally provided between the first air cooler 200 and the first cooler 121.

[0118] During the energy release process, the 195°C first cooling medium passes through the heat release path of the heater 320 and exchanges heat with the compressed gas in the heat absorption path of the heater 320. After the first cooling medium is cooled, it enters the first air cooler 200 and continues to cool to 60°C. It is then sent to the cold storage tank 500 for storage. In the next energy storage process, the first cooling medium enters the heat absorption path of the first cooler 121 from the cold storage tank 500 to cool the compressed air in the heat release path of the first cooler 121.

[0119] During the energy storage process, the first cooling medium at 60° C. stored in the cold storage tank 500 enters the heat absorption passage of the first cooler 121 to cool the compressed air in the heat release passage of the first cooler 121 .

[0120] According to an embodiment provided by the present invention, the liquid air energy storage power station further includes a heat storage tank 600, the inlet of the heat storage tank 600 is connected to the outlet of the heat absorption path of the first cooler 121, and the outlet of the heat storage tank 600 is connected to the inlet of the heat release path of the heater 320. In this embodiment, since the energy storage process of the energy storage device 100 and the energy release process of the energy release device 300 are performed independently, a heat storage tank 600 is added between the second cooler 122 and the heater 320. Since the inlet temperature of the first cooling medium at the heat absorption path of the first cooler 121 is reduced, while the outlet temperature of the heat absorption path of the first cooler 121 remains unchanged, the temperature rise degree and heat exchange efficiency of the first cooling medium are improved, and the flow rate of the first cooling medium can be reduced under the same heat load, thereby reducing the volume of the heat storage tank 600.

[0121] During the energy storage process, the first cooling medium at 60°C stored in the cold storage tank 500 enters the heat absorption path of the first cooler 121, and performs heat exchange on the compressed air in the heat release path of the first cooler 121. After the first cooling medium is heated to 195°C, it enters the hot storage tank 600 for storage. In the next energy release process, the first cooling medium enters the heat release path of the heater 320 from the hot storage tank 600 to heat the compressed air in the heat absorption path of the heater 320.

[0122] During the energy release process, the 195°C first cooling medium passes through the heat release path of the heater 320 and exchanges heat with the compressed gas in the heat absorption path of the heater 320. After the first cooling medium is cooled, it enters the first air cooler 200 and continues to cool to 60°C. It is then sent to the cold storage tank 500 for storage. In the next energy storage process, the first cooling medium enters the heat absorption path of the first cooler 121 from the cold storage tank 500 to cool the compressed air in the heat release path of the first cooler 121.

[0123] According to an embodiment provided by the present invention, the energy release device 300 includes a plurality of gas expanders 310 and a plurality of heaters 320, and the plurality of heaters 320 and the plurality of gas expanders 310 are alternately arranged in series. In this embodiment, one heater 320 is arranged in conjunction with one gas expander 310, and the heater 320 and the gas expander 310 are combined and alternately connected in series on the air path to form a multi-stage energy release device 300. The multi-stage heaters 320 heat the high-pressure and normal-temperature air step by step, and the multi-stage gas expanders 310 release the pressure of the high-pressure and normal-temperature air step by step, and finally form low-pressure and high-temperature air for exhaust.

[0124] The heat release passages of each stage of the heaters 320 are connected in parallel and then in series to the first cooling circuit, that is, the inlet of the heat release passage of each heater 320 is connected in parallel to the outlet of the heat storage tank 600, and the outlet of the heat release passage of each heater 320 is connected in parallel to the inlet of the heat release channel of the first air cooler 200.

[0125] In this embodiment, the energy release device 300 includes a total of 4 heaters 320 and 4 gas expanders 310, which are connected in series along the air flow direction: high-pressure heater, high-pressure gas expander, medium-pressure heater, medium-pressure gas expander, low-pressure heater, low-pressure gas expander, low-low-pressure heater and low-low-pressure gas expander.

[0126] According to an embodiment provided by the present invention, the energy storage device 100 includes a plurality of air compressors 110 and a plurality of cooling units 120, and the plurality of air compressors 110 and the plurality of cooling units 120 are alternately arranged in series. In this embodiment, one air compressor 110 and one cooling unit 120 are arranged in coordination, and the air compressor 110 and the cooling unit 120 are combined and alternately connected in series on the air path to form a multi-stage energy storage device 100. The air compressors 110 at each stage pressurize and heat the outside air, and the cooling units 120 at each stage compress and recover the high-temperature and high-pressure air, and finally form high-pressure and normal-temperature air for discharge.

[0127] The heat absorption paths of the first coolers 121 of each stage are connected in parallel and then connected in series to the first cooling circuit, that is, the inlet of the heat absorption path of each first cooler 121 is connected in parallel to the outlet of the cold storage tank 500, and the outlet of the heat absorption path of each first cooler 121 is connected in parallel to the inlet of the hot storage tank 600. The heat absorption paths of the second coolers 122 of each stage are connected in parallel and then connected in series to the second cooling circuit, that is, the inlet of the heat absorption path of each second cooler 122 is connected in parallel to the outlet of the second air cooler 400, and the outlet of the heat absorption path of each second cooler 122 is connected in parallel to the inlet of the second air cooler 400.

[0128] In this embodiment, the energy storage device 100 includes three air compressors 110, three first coolers 121 and three second coolers 122, which are connected in series along the air flow direction: a low-pressure air compressor, a low-pressure first cooler, a low-pressure second cooler, a medium-pressure air compressor, a medium-pressure first cooler, a medium-pressure second cooler, a high-pressure air compressor, a high-pressure first cooler and a high-pressure second cooler.

[0129] According to an embodiment provided by the present invention, the energy storage device 100 also includes an air purifier 700, which is arranged between two adjacent cooling units 120, and the inlet of the air purifier 700 is connected to the outlet of the heat release passage of the second cooler 122, and the outlet of the air purifier 700 is connected to the inlet of the air compressor 110.

[0130] In this embodiment, the air purifier 700 is arranged between two adjacent stages, that is, between the second cooler 122 of the previous stage and the air compressor 110 of the next stage. The air purifier 700 can purify the compressed air before entering the air compressor 110 to prevent impurities from mixing in. In this embodiment, the air purifier 700 is arranged between the medium-pressure second cooler and the high-pressure air compressor, and the air is purified before being discharged after the last stage of compression and cooling.

[0131] In one embodiment, the outside air passes through the air filter 900 to filter out impurities before entering the energy storage device 100 .

[0132] According to an embodiment provided by the present invention, the liquid air energy storage power station further includes a cold box 800, the inlet of the cold box 800 is connected to the outlet of the heat release path of the second cooler 122, and the outlet of the cold box 800 is connected to the inlet of the heat absorption path of the heater 320. In this embodiment, the cold box 800 connects the energy storage device 100 with the energy release device 300 on the air flow path, that is, the outlet of the heat release path of the second cooler 122 is connected to the inlet of the heat absorption path of the heater 320 through the cold box 800, and the cold box 800 can be used as a cold storage device to heat and reheat the incoming high-pressure and low-temperature air to form high-pressure and normal-temperature air.

[0133] During the energy storage process, the outside air passes through the subsequent air compressor 110 and the cooling unit 120 in sequence, becomes high-pressure normal-temperature air and enters the cold box 800 of the cold storage unit. During the energy release process, the high-pressure normal-temperature air reheated by the cold box 800 enters the heater 320 and the gas expander 310, expands and does work, and finally becomes low-pressure air and is discharged.

[0134] The type of each cooler is not limited, as long as it meets the working condition requirements and is economical and reasonable. Taking the shell and tube heat exchanger as the first cooler 121 and the second cooler 122 as an example, the first cooling medium and the second cooling medium are both water. The specific comparison values ​​are shown in the following table:

[0135]

[0136] In addition, the heat storage medium generated in the compression device can be reduced to a certain extent. Taking water as the cooling medium, the total amount of hot water in the compression stage of the prior art is 2,600 tons, and the total amount of hot water in the energy storage process of the present invention is 2,300 tons. According to the density of water at 195°C, the 600-volume heat storage tank can save about 350m 3 .

[0137] 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 control method for a circulating water system of a liquid air energy storage power station, characterized in that: The liquid air energy storage power station includes a circulating water system, an energy storage device and an energy release device. The circulating water system includes a first storage tank and a second storage tank. The first storage tank, the heat absorption path of the energy storage device, the second storage tank and the heat release path of the energy release device are sequentially connected to form a loop suitable for circulating water. The exhaust port of the second storage tank is connected to the air inlet of the first storage tank, including: Determine that the actual pressure in the second storage tank reaches the first set pressure, and control the gas in the second storage tank to be discharged into the first storage tank, wherein the first set pressure is the maximum operating pressure of the second storage tank, so that the mixed gas of air and water vapor in the second storage tank is discharged to the first storage tank as a normal temperature circulating water storage tank, the water vapor in the mixed gas is recovered in the first storage tank, and the air is directly discharged; The circulating water system further includes an air cooling device, wherein the first storage tank, the heat release path of the air cooling device and the heat absorption path of the energy storage device are connected in sequence, and further includes: Determine that the average temperature of the external environment is greater than the first set temperature and less than or equal to the second set temperature, and control the air cooling device to operate at the set power; or, Determine that the average temperature of the external environment is greater than the second set temperature, and control the air cooling device to operate when the actual temperature of the external environment is less than the second set temperature; or, Determine that the average temperature of the external environment is less than or equal to the first set temperature, and control the air cooling device to operate when the actual temperature of the external environment is greater than the first set temperature; The first set temperature has a value range of 0-2°C, and the second set temperature has a value range of 18-20°C.

2. The control method of the circulating water system of the liquid air energy storage power station according to claim 1, characterized in that: Also includes: Determine that the operating time of the energy release device reaches a set time, and control the second storage tank to increase the temperature, wherein the set time is 3 / 5 to 2 / 3 of the total time of the energy release stage.

3. The control method of the circulating water system of the liquid air energy storage power station according to claim 1, characterized in that: Also includes: Determine that in the energy release stage, the actual stock of circulating water in the second storage tank reaches the set stock, and control the second storage tank to increase the temperature, wherein the set stock is 2 / 5 to 1 / 3 of the circulating water stock of the second storage tank after the energy storage stage.

4. The control method of the circulating water system of the liquid air energy storage power station according to claim 2 or 3, characterized in that: The controlling the temperature of the second storage tank to increase includes electrically heating the second storage tank, or increasing the amount of circulating water in the second storage tank.

5. The control method of the circulating water system of the liquid air energy storage power station according to claim 1, characterized in that: Also includes: When the energy storage device is turned on, increasing the actual pressure in the second storage tank; Determine that the actual pressure in the second storage tank reaches a second set pressure, and control the heat absorption passage of the energy storage device to deliver circulating water to the second storage tank, wherein the second set pressure is the saturated steam pressure corresponding to the high-temperature circulating water.

6. The control method of the circulating water system of the liquid air energy storage power station according to claim 1, characterized in that: It is determined that the average temperature of the external environment is greater than the second set temperature, and the air cooling device is controlled to perform wet operation when the actual temperature of the external environment is less than the second set temperature.

7. The control method of the circulating water system of the liquid air energy storage power station according to claim 1, characterized in that: Determine that the average temperature of the external environment is less than or equal to the first set temperature, and control the air cooling device to perform dry operation when the actual temperature of the external environment is greater than the first set temperature.

8. A liquid air energy storage power station, characterized in that: A control method for a circulating water system of a liquid air energy storage power station according to any one of claims 1 to 7 is implemented, wherein a valve body is provided in a pipeline connecting the exhaust port of the second storage tank and the air inlet of the first storage tank.

9. The liquid air energy storage power station according to claim 8, characterized in that: The first tank is provided with cooling means suitable for condensing steam.

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